Subspace clustering of DNA microarray data: theory, evaluation, and applications - Tchagang, Alain B.; Famili, Fazel; Pan, Youlian (International Journal of Computational Models and Algorithms in Medicine, 2014)
Identification of biological significant subspace clusters (biclusters and triclusters) of genes from microarray experimental data is a very daunting task that emerged, especially with the development of high throughput technologies. Several methods and applications of subspace clustering (biclustering and triclustering) in DNA microarray data analysis have been developed in recent years. Various computational and evaluation methods based on diverse principles were introduced to identify new similarities among genes. This review discusses and compares these methods, highlights their mathematical principles, and provides insight into the applications to solve biological problems.

Integrated planar waveguide devices for evanescent field sensing and spectroscopy - Cheben, P.; Janz, S.; Sabourin, N.; Xu, D.-X.; Ding, H.; Wang, S.; Schmid, J. H.; Delage, A.; Lapointe, J.; Sinclair, W.; Ma, P.; Logan, S.; et al. (ICTON 2014: 16th International Conference on Transparent Optical Networks: Graz, 6th-10th July, 2014, 2014)
The silicon photonic wire evanescent field (PWEF) sensor platform offers the advantages of small sensor size, high levels of function integration, and low cost manufacturing that comes with the use of established semiconductor fabrication processes. The technology should be fully compatible with existing infrastructure in molecular analysis and research and the manufactured sensor array chip cost should be low enough that the chips can be considered disposable. Furthermore, since many applications require simultaneous monitoring of many different simultaneous binding reactions, the possibility of integrating tens or even hundreds of independent molecular sensors on a single disposable sensor chip is very compelling. We present an overview of our multiplexed photonic wire sensor chip and a reader instrument that allows up to 128 independent binding reactions to be monitored simultaneously. A complete photonic wire molecular biosensor microarray chip architecture and supporting instrumentation is discussed. This microarray system is used to demonstrate a multiplexed assay for serotyping E. coli bacteria based on polyclonal antibody probe molecules. A coherent detection scheme that enables direct read-out of the optical phase and an order of magnitude enhancement of sensitivity compared to conventional detection is also discussed. Finally, we present advances in Fourier-transform interferometer arrays for spectroscopic sensing. A planar waveguide Fourier-transform spectrometer with densely arrayed Mach-Zehnder interferometers is presented. Subwavelength gratings are used to produce an optical path difference without waveguide bends. The fabricated device comprises of an array of 32 Mach-Zehnder interferometers, which produce a spatial interferogram without any moving parts, yielding a spectral resolution of 50 pm and a free-spectral range of 0.78 nm. As a result of similar propagation losses in subwavelength grating waveguides and conventional strip waveguides, loss imbalance is minimized and high interferometric extinction ratio of -25 to -30 dB is obtained. Furthermore, phase and amplitude errors arising from normal fabrication variation are compensated by the spectral retrieval process using calibration measurements.

The post-translational modification of the Clostridium difficile flagellin affects motility, cell surface properties and virulence - Faulds-Pain, Alexandra; Twine, Susan M.; Vinogradov, Evgeny; Strong, Philippa C. R.; Dell, Anne; Buckley, Anthony M.; Douce, Gillian R.; Valiente, Esmeralda; Logan, Susan M.; Wren, Brendan W. (Molecular Microbiology, 2014)
Clostridium difficile is a prominent nosocomial pathogen, proliferating and causing enteric disease in individuals with a compromised gut microflora. We characterized the post-translational modification of flagellin in C. difficile 630. The structure of the modification was solved by nuclear magnetic resonance and shown to contain an N-acetylglucosamine substituted with a phosphorylated N-methyl-l-threonine. A reverse genetics approach investigated the function of the putative four-gene modification locus. All mutants were found to have truncated glycan structures by LC-MS/MS, taking into account bioinformatic analysis, we propose that the open reading frame CD0241 encodes a kinase involved in the transfer of the phosphate to the threonine, the CD0242 protein catalyses the addition of the phosphothreonine to the N-acetylglucosamine moiety and CD0243 transfers the methyl group to the threonine. Some mutations affected motility and caused cells to aggregate to each other and abiotic surfaces. Altering the structure of the flagellin modification impacted on colonization and disease recurrence in a murine model of infection, showing that alterations in the surface architecture of C. difficile vegetative cells can play a significant role in disease. We show that motility is not a requirement for colonization, but that colonization was compromised when the glycan structure was incomplete.

J. Ignacio García Alonso and Pablo Rodríguez-González: isotope dilution mass spectrometry - Meija, Juris (Analytical and Bioanalytical Chemistry, 2014)

The last alchemist in Paris - Meija, Juris (Chemistry International, 2014)

Quantitative high-throughput analysis of domoic acid in mussel tissue homogenates using laser ablation electrospray ionization – MS/MS - Beach, Daniel; Walsh, Callee M.; McCarron, Pearse (2014)
We investigated the use of Laser Ablation Electrospray Ionization (LAESI) with MS/MS detection for Domoic Acid (DA) analysis directly from mussel tissue homogenates without sample extraction, cleanup or chromatographic separation. DA could be selectively detected directly from mussel tissue homogenates using LAESI-MS/MS in selected reaction monitoring scan mode. A matrix matched calibration curve was used to quantify mussel tissue reference materials and results were in good agreement with two established methods, LC-UV and LC-MS/MS, within the linear range. Most notable is the decrease in run time from about 20 minutes for a typical chromatographic method to about 10 seconds per sample for LAESI-MS/MS.

Isolation of minor and novel azaspiracids: structure elucidation and toxicology - Kilcoyne, Jane; Nulty, Ciara; McCarron, Pearse; Jauffrais, Thierry; Twiner, M.; Quilliam, Michael Arthur; Hess, Philipp; Miles, Christopher Owen (Toxicon, 2014)
Special issue of 21st Meeting of the French-Society-of-Toxicology (SFET) Azaspiracids (AZAs) were discovered following a poisoning event in the Netherlands in 1995 after people consumed contaminated shellfish harvested in Ireland. The symptoms included nausea, vomiting, diarrhea, and stomach cramps. AZA1, -2 and -3 were identified as the source of the illnesses. LC MS/MS is the EU reference method for detection of AZAs, with the regulatory limit set at 160 μg/kg AZA1 equivalents. Extensive research has revealed that more than 20 additional AZA analogues exist. The phytoplankton Azadinium spinosum produces AZA1 and -2 while AZA3 and many of the other analogues are metabolic products formed in the shellfish. To date AZA1-6 have been isolated, chemically characterized and assessed for their toxicological impact using both in vitro and in vivo assays. Cytotoxicity studies indicate that AZA1, -2, and -3 elicit a lethal response that is both concentration- and time- dependent, with EC50 values in the sub- to low nanomolar range. The availability of as many AZA analogues as possible, in sufficient quantity and purity, is imperative to highlight the analogues which are relevant for public health protection. Here we describe efforts made to identify hitherto unknown analogues of the AZA group in phytoplankton and shellfish as well as attempts to isolate some of the known minor AZA analogues using a series of partitioning and column chromatography steps. Samples were purified in sufficient quantities to enable full structural elucidation by LC-MS/MS and NMR and toxicological assessment using the Jurkat T lymphocyte cell assay. Some the purified compounds had significant differences in their structure from the main AZA analogues which enabled examination of structure-activity relationships.

NRC-Canada-2014: recent improvements in the sentiment analysis of tweets - Zhu, Xiaodan; Kiritchenko, Svetlana; Mohammad, Saif (Proceedings of the 8th International Workshop on Semantic Evaluation (SemEval 2014), 2014)
This paper describes state-of-the-art statistical systems for automatic sentiment analysis of tweets. In a Semeval-2014 shared task (Task 9), our submissions obtained highest scores in the term-level sentiment classification subtask on both the 2013 and 2014 tweets test sets. In the message-level sentiment classification task, our submissions obtained highest scores on the Live- Journal blog posts test set, sarcastic tweets test set, and the 2013 SMS test set. These systems build on our SemEval-2013 sentiment analysis systems (Mohammad et al., 2013) which ranked first in both the term- and message-level subtasks in 2013. Key improvements over the 2013 systems are in the handling of negation. We create separate tweet-specific sentiment lexicons for terms in affirmative contexts and in negated contexts.

NRC-Canada-2014: detecting aspects and sentiment in customer reviews - Kiritchenko, Svetlana; Zhu, Xiaodan; Cherry, Colin; Mohammad, Saif (Proceedings of the 8th International Workshop on Semantic Evaluation (SemEval 2014), 2014)
Reviews depict sentiments of customers towards various aspects of a product or service. Some of these aspects can be grouped into coarser aspect categories. SemEval-2014 had a shared task (Task 4) on aspect-level sentiment analysis, with over 30 teams participated. In this pa- per, we describe our submissions, which stood first in detecting aspect categories, first in detecting sentiment towards aspect categories, third in detecting aspect terms, and first and second in detecting sentiment towards aspect terms in the laptop and restaurant domains, respectively.

Thermal conductivity of nanotube assemblies and superfiber materials - Jakubinek, Michael B. (Nanotube Superfiber Materials, 2014)
Individual carbon nanotubes (CNTs) have been reported to have the highest thermal conductivities of any known material. However, significant variability exists both for the reported thermal conductivities of individual CNTs and the thermal conductivities measured for macroscopic CNT assemblies (e.g. CNT films, buckypapers, arrays, and fibers), which range from comparable to metals to aerogel-like. This chapter reviews the current status of the field, summarizing a wide selection of experimental results and drawing conclusions regarding present limitations of the thermal conductivity of CNT assemblies and opportunities for improvement of the performance of nanotube superfiber materials.

Water in star-forming regions with Herschel (WISH): V. the physical conditions in low-mass protostellar outflows revealed by multi-transition water observations - Mottram, J. C.; Kristensen, L. E.; Van Dishoeck, E. F.; Bruderer, S.; San José-García, I.; Karska, A.; Visser, R.; Santangelo, G.; Benz, A. O.; Bergin, E. A.; Caselli, P.; Herpin, F.; et al. (Astronomy & Astrophysics, 2014)
Context. Outflows are an important part of the star formation process as both the result of ongoing active accretion and one of the main sources of mechanical feedback on small scales. Water is the ideal tracer of these effects because it is present in high abundance for the conditions expected in various parts of the protostar, particularly the outflow. Aims. We constrain and quantify the physical conditions probed by water in the outflow-jet system for Class 0 and I sources. Methods. We present velocity-resolved Herschel HIFI spectra of multiple water-transitions observed towards 29 nearby Class 0/I protostars as part of the WISH guaranteed time key programme. The lines are decomposed into different Gaussian components, with each component related to one of three parts of the protostellar system; quiescent envelope, cavity shock and spot shocks in the jet and at the base of the outflow. We then use non-LTE radex models to constrain the excitation conditions present in the two outflow-related components. Results. Water emission at the source position is optically thick but effectively thin, with line ratios that do not vary with velocity, in contrast to CO. The physical conditions of the cavity and spot shocks are similar, with post-shock H2 densities of order 105 − 108 cm-3 and H2O column densities of order 1016 − 1018 cm-2. H2O emission originates in compact emitting regions: for the spot shocks these correspond to point sources with radii of order 10−200 AU, while for the cavity shocks these come from a thin layer along the outflow cavity wall with thickness of order 1−30 AU. Conclusions. Water emission at the source position traces two distinct kinematic components in the outflow; J shocks at the base of the outflow or in the jet, and C shocks in a thin layer in the cavity wall. The similarity of the physical conditions is in contrast to off-source determinations which show similar densities but lower column densities and larger filling factors. We propose that this is due to the differences in shock properties and geometry between these positions. Class I sources have similar excitation conditions to Class 0 sources, but generally smaller line-widths and emitting region sizes. We suggest that it is the velocity of the wind driving the outflow, rather than the decrease in envelope density or mass, that is the cause of the decrease in H2O intensity between Class 0 and I sources.
Keywords: stars: formation; ISM: jets and outflows; ISM: molecules; stars: protostars

Thermoreversible hydrogels based on triblock copolymers of poly(ethylene glycol) and carboxyl functionalized poly(ε-caprolactone): the effect of carboxyl group substitution on the transition temperature and biocompatibility in plasma - Safaei nikouei, Nazila; Vakili, Mohammad Reza; Bahniuk, Markian S.; Unsworth, Larry; Akbari, Ali; Wu, Jianping; Lavasanifar, Afsaneh (Acta Biomaterialia, 2014)
In this study we report on the development, characterization and plasma protein interaction of novel thermoresponsive in situ hydrogels based on triblock copolymers of poly(ethylene glycol) (PEG) and poly(α-carboxyl-co-benzyl carboxylate)-ε-caprolactone (PCBCL) having two different degrees of carboxyl group substitution on the PCBCL block. Block copolymers were synthesized through ring-opening polymerization of α-benzyl carboxylate-ε-caprolactone by dihydroxy PEG, leading to the production of poly(α-benzyl carboxylate-ε-caprolactone)–PEG–poly(α-benzyl carboxylate-ε-caprolactone) (PBCL–PEG–PBCL). This was followed by partial debenzylation of PBCL blocks under controlled conditions, leading to the preparation of PCBCL–PEG–PCBCL triblock copolymers with 30 and 54 mol.% carboxyl group substitution. Prepared PCBCL–PEG–PCBCL block copolymers have been shown to have a concentration-dependent sol to gel transition as a result of an increase in temperature above ∼29 °C, as evidenced by the inverse flow method, differential scanning calorimetry and dynamic mechanical analysis. The sol–gel transition temperature/concentration and dynamic mechanical properties of the gel were found to be dependent on the level of carboxyl group substitution. Both hydrogels (30 and 54 mol.% carboxyl group substitution) showed similar amounts of protein adsorption but striking differences in the profiles of the adsorbed proteome. Additionally, the two systems showed similarities in their clot formation kinetics but substantial differences in clot endpoints. The results show great promise for the above-mentioned thermoreversible in situ hydrogels as biocompatible materials for biomedical applications.
Keywords: in situ hydrogel; thermoresponsive; protein adsorption; biodegradable gel; biocompatibility

The Subaru high-z quasar survey: discovery of faint z ~ 6 quasars - Kashikawa, Nobunari; Ishizaki, Yoshifumi; Willott, Chris J.; Onoue, Masafusa; Im, Myungshin; Furusawa, Hisanori; Toshikawa, Jun; Ishikawa, Shogo; Niino, Yuu; Shimasaku, Kazuhiro; Ouchi, Masami; Hibon, Pascale (The Astrophysical Journal, 2014)
We present the discovery of one or two extremely faint z ~ 6 quasars in 6.5 deg2 utilizing a unique capability of the wide-field imaging of the Subaru/Suprime-Cam. The quasar selection was made in (i'-zB ) and (zB -zR ) colors, where zB and zR are bandpasses with central wavelengths of 8842 Å and 9841 Å, respectively. The color selection can effectively isolate quasars at z ~ 6 from M/L/T dwarfs without the J-band photometry down to zR < 24.0, which is 3.5 mag deeper than the Sloan Digital Sky Survey (SDSS). We have selected 17 promising quasar candidates. The follow-up spectroscopy for seven targets identified one apparent quasar at z = 6.156 with M 1450 = –23.10. We also identified one possible quasar at z = 6.041 with a faint continuum of M 1450 = –22.58 and a narrow Lyα emission with HWHM =427 km s–1, which cannot be distinguished from Lyman α emitters. We derive the quasar luminosity function at z ~ 6 by combining our faint quasar sample with the bright quasar samples by SDSS and CFHQS. Including our data points invokes a higher number density in the faintest bin of the quasar luminosity function than the previous estimate employed. This suggests a steeper faint-end slope than lower z, though it is yet uncertain based on a small number of spectroscopically identified faint quasars, and several quasar candidates still remain to be diagnosed. The steepening of the quasar luminosity function at the faint end does increase the expected emission rate of the ionizing photon; however, it only changes by a factor of approximately two to six. This was found to still be insufficient for the required photon budget of reionization at z ~ 6.

NOTeS: symbols of the elements - Meija, Juris (Chemistry International: Newsmagazine for IUPAC, 2014)
Four systems of notation have become so universal that they now surpass most linguistic barriers. These are mathematical signs and symbols, the International System of Units, the traditional musical notation, and the symbols for chemical elements.1 Imagine the world with different symbols for the plus sign in various lan- guages, or different symbols for hydrogen. Although chemists worldwide now enjoy the peace of univer-sally accepted symbols for all elements which are not subject to translation, it took a long time for such convention to root.

Social media in remote first nation communities - Molyneaux, Heather; O'donnell, Susan; Kakekaspan, Crystal; Walmark, Brian; Budka, Philipp; Gibson, Kerri (Canadian Journal of Communication, 2014)
Community resilience in First Nations includes ties to people both inside and outside the community, intergenerational communication, the sharing of stories, and family and community connectedness. This study, based on a survey of Internet users in the Sioux Lookout region of Northwestern Ontario, explores the link between social networking sites and community resilience. The region is home to some of the most isolated First Nation (indigenous)communities in Canada. Cultural and familial links between these communities are strong, yet until recent use of the Internet, maintaining regular communications to strengthen cultural ties was challenging. This study examines the links between travel and communication online, the ways in which social media are used to preserve culture and maintain communication, and the implications of social networking for community resilience.
Keywords: first nations; indigenous; social media; social networking; remote communities; rural; community resilience; internet

T3DB: the toxic exposome database - Wishart, D.; Arndt, D.; Pon, A.; Sajed, T.; Guo, A. C.; Djoumbou, Y.; Knox, C.; Wilson, M.; Liang, Y.; Grant, J.; Liu, Y.; Goldansaz, S. A.; et al. (Nucleic Acids Research, 2014)
The exposome is defined as the totality of all human environmental exposures from conception to death. It is often regarded as the complement to the genome, with the interaction between the exposome and the genome ultimately determining one's phenotype. The ‘toxic exposome’ is the complete collection of chronically or acutely toxic compounds to which humans can be exposed. Considerable interest in defining the toxic exposome has been spurred on by the realization that most human injuries, deaths and diseases are directly or indirectly caused by toxic substances found in the air, water, food, home or workplace. The Toxin-Toxin-Target Database (T3DB - www.t3db.ca) is a resource that was specifically designed to capture information about the toxic exposome. Originally released in 2010, the first version of T3DB contained data on nearly 2900 common toxic substances along with detailed information on their chemical properties, descriptions, targets, toxic effects, toxicity thresholds, sequences (for both targets and toxins), mechanisms and references. To more closely align itself with the needs of epidemiologists, toxicologists and exposome scientists, the latest release of T3DB has been substantially upgraded to include many more compounds (>3600), targets (>2000) and gene expression datasets (>15 000 genes). It now includes extensive data on ‘normal’ toxic compound concentrations in human biofluids as well as detailed chemical taxonomies, informative chemical ontologies and a large number of referential NMR, MS/MS and GC-MS spectra. This manuscript describes the most recent update to the T3DB, which was previously featured in the 2010 NAR Database Issue.

Supramolecular interactions in secondary plant cell walls: effect of lignin chemical composition revealed with the molecular theory of solvation - Silveira, Rodrigo L.; Stoyanov, Stanislav R.; Gusarov, Sergey; Skaf, Munir S.; Kovalenko, Andriy (The Journal of Physical Chemistry Letters, 2014)
Plant biomass recalcitrance, a major obstacle to achieving sustainable production of second generation biofuels, arises mainly from the amorphous cell-wall matrix containing lignin and hemicellulose assembled into a complex supramolecular network that coats the cellulose fibrils. We employed the statistical-mechanical, 3D reference interaction site model with the Kovalenko–Hirata closure approximation (or 3D-RISM-KH molecular theory of solvation) to reveal the supramolecular interactions in this network and provide molecular-level insight into the effective lignin–lignin and lignin–hemicellulose thermodynamic interactions. We found that such interactions are hydrophobic and entropy-driven, and arise from the expelling of water from the mutual interaction surfaces. The molecular origin of these interactions is carbohydrate−π and π–π stacking forces, whose strengths are dependent on the lignin chemical composition. Methoxy substituents in the phenyl groups of lignin promote substantial entropic stabilization of the ligno-hemicellulosic matrix. Our results provide a detailed molecular view of the fundamental interactions within the secondary plant cell walls that lead to recalcitrance.
Keywords: 3D-RISM-KH molecular theory of solvation; biofuel; hemicellulose; hydrophobic interactions; plant biomass recalcitrance; solvation free energy

Structure and composition of single Pt–Ru electrocatalyst nanoparticles supported on multiwall carbon nanotubes - Paraguay-delgado, Francisco; Malac, Marek; Alonso-nuñez, Gabriel (Materials Research Express, 2014)
Individual Pt-Ru nanoparticles (NPs) supported on multiwall carbon nanotubes (MWCNTs) synthesized by microemulsion method were characterized by nano beam diffraction (NBD) and high resolution imaging in transmission electron microscopy (TEM). Comparing the TEM images and NBD to simulations provided insight into particle composition, structure and morphology in three dimensions. In particular, the NBD allowed us to detect various components of the individual NPs that would be difficult to observe otherwise. We find that the NPs contain four different components: Pt–RuO2, Pt–Ru, RuO2 and metallic Pt. Often an individual NP is composed of more than one component. The most frequently encountered external morphology is close to a spherical shape and ~3.7 nm in diameter. The collective properties of NPs' assemblies were studied by thermogravimetry, differential thermal analysis and x-ray diffraction. The results allowed us to gain some insight into the relation of the NPs' structure and composition with their catalytic performance, and revealed the presence of components not detectable by bulk methods. The electrocatalytic properties were evaluated by CO stripping, methanol oxidation and oxygen reduction. Bulk characterization methods miss many properties and structures present in the sample due to low volume fraction and due to overlap of reflections. Single NPs should be analyzed to obtain reliable indication of sample composition.
Keywords: single Pt-Ru nanoparticle structure; electrocatalyst; nano-beam electron diffraction; microemulsion

Selection of chemotactic adipose-derived stem cells using a microfluidic gradient generator - Natarajan, Kanmani; Tian, Chantal; Xiang, Bo; Chi, Chao; Deng, Jixian; Zhang, Rundi; Freed, Darren H.; Arora, Rakesh C.; Tian, Ganghong; Lin, Francis (RSC Advances, 2014)
Stem cells hold great promise for treating various degenerative diseases and conditions. However, the outcomes of preclinical and clinical cell therapy studies are still not close to our expectation. We believe that the unsatisfactory outcomes of cell therapy are at least partially due to insufficient homing of implanted stem cells into target organs and the use of heterogeneous cell populations for cell therapy. Therefore, there is a need to develop an effective guiding technique for stem cells to migrate to the target organs and to isolate effective stem cell populations. Toward this direction, we have previously demonstrated chemotaxis of rat adipose-derived stem cells (ASCs) to a well-defined gradient of epidermal growth factor (EGF) using a microfluidic device. In the current study, we further developed a microfluidics-based method for selecting chemotactic ASCs to EGF. This method integrates cell patterning, chemotaxis and cell extraction on a single microfluidic gradient-generating device. Post-extraction analysis confirmed the higher chemotactic migration of the extracted cells to EGF. Consistently, the extracted chemotactic ASCs shows up-regulated surface expression of the EGF receptor and its downstream signaling event upon EGF stimulation. The results suggest that our method provides a new effective approach for the selection of specific stem cell populations. It is also expected that the use of the selectively extracted stem cells could enhance stem cell homing to target organs and consequently improve the outcome of cell therapy.

Propeller wake wash for ice management - Bastin, Tony; Zubayer, Abir; Veitch, Brian; Akinturk, Ayhan; Wang, Jungyong; Billard, Randy (2014 Oceans: St. John's, 2014)
Propeller wake wash has been used effectively for ice management operations for years. The main uses of propeller wake wash include clearing pack ice and broken ice from protected installations and shipping channels. A numerical model of a propeller wake has been developed to simulate the effects of the wake, or jet, on ice pieces floating on the water surface. The propeller wake is modeled using the theory of horizontal round jets as well as empirical equations derived from previous experiments. The modification of the propeller jet due to the free surface is modeled using experimental results for round jets. A dynamic model of ice piece motion is used to simulate the action of the jet on ice pieces. Model predictions are compared to experimental results of pack ice subjected to propeller wake wash. The analysis shows that the model can be used to simulate the clearing of pack ice. The model was subsequently incorporated in a real time simulator to assess its performance in 3D rendered virtual environments.
Keywords: numerical simulation; ice management; propeller wake wash

Impact of layup rate on the quality of fiber steering/cut-restart in automated fiber placement processes - Chen, Jihua; Chen-keat, Teresa; Hojjati, Mehdi; Vallee, A. J.; Octeau, Marc-andre; Yousefpour, Ali (Science and Engineering of Composite Materials, 2014)
Developing reliable processes is one of the key elements in producing high-quality composite components using an automated fiber placement (AFP) process. In this study, both simulation and experimental studies were carried out to investigate fiber steering and cut/restart under different processing parameters, such as layup rate and compaction pressure, during the AFP process. First, fiber paths were designed using curved fiber axes with different radii. Fiber placement trials were then conducted to investigate the quality of the steered fiber paths. Furthermore, a series of sinusoidal fiber paths were fiber placed and investigated. Moreover, a six-ply laminate with cut-outs in it was manufactured in the cut/restart trials. The accuracy of the fiber cut/restart was compared at different layup rates for both one- and bi-directional layups. Experimental results show that it was possible to layup steered fiber paths with small radii of curvature (minimum 114 mm) designed for this study when the proper process condition was used. It was observed from the cut/restart trials that the quality of tow cut was independent of layup speed; however, the accuracy of tow restart was related to the layup speed. The faster the layup speed, the less accurate was the tow restart.
Keywords: automated fiber placement; cut/restart; fiber steering

High resolution projector for 3D imaging - Drouin, Marc-Antoine; Blais, Francois; Godin, Guy (2014 2nd International Conference on 3D Vision, 2014)
This paper proposes a hybrid software-hardware high-resolution projection system for 3D imaging based on fringe projection. The proposed solution combines the advantages of a digital projection with those of an analogue one. It is programmable and allows a high projection rate by avoiding mechanical displacements in the projection system. Moreover, it does not suffer from the limitations of digital systems such as the presence of inter-pixel gaps and limited resolution. The proposed projection system is relatively inexpensive to build since it is composed of a simple arrangement off-the-shelf components. The system is a combination of a low-resolution digital device such as a DMD, LCoS or LCD, some optical components and software to generate the fringe patterns. A prototype of a 3D scanner based on the proposed projection system is used to asses the fitness of the proposed technology.
Keywords: structure light; 3D imaging; fringe projection

Azaspiracids: chemistry, biosynthesis, metabolism, and detection - Hess, Philipp; McCarron, Pearse; Krock, Bernd; Kilcoyne, Jane; Miles, Christopher O.; Botana, Luis M. (Seafood and Freshwater Toxins: Pharmacology, Physiology, and Detection, 2014)
This chapter describes the chemical characteristics of azaspiracids (AZAs) to complete the view on this toxin group, with two other chapters in this book dedicated to toxicological1 and ecological aspects.2 AZAs are a group of polyether toxins first reported to cause food poisoning in 1995.3,4 Since then, a small number of food poisoning incidents have occurred, and it is now accepted that this group of compounds requires regulation to protect public health.5–8 At least six risk assessments have been carried out over the last decade to determine appropriate levels for regulatory limits in order to protect public health,1 yet all these assessments are based on a single poisoning incident in 1997 and attempt to set levels based on the presence of just three analogues: AZA1, AZA2, and AZA3. Over the last 5 years, more than 30 additional analogues have been described, with both biotransformation in shellfish and chemical interconversion shown to contribute to the chemical diversity of this toxin group. In the following sections, we review AZAs to distinguish those analogues that are formed by the microalgae themselves from those that are formed by biotransformation or by chemical modification during extraction or sample treatment. Subsequently, chemical characteristics such as solubility and pH and thermal stability are reviewed. Methods for discovery of AZA analogues are discussed, including bioassays and chemical techniques. Finally, methodology for detection and quantitation is reviewed with consideration of quality control in routine analytical settings.

Relationship between helicopter rotor tuning and physiological stress - Wright-Beatty, Heather E.; Keillor, Jocelyn M.; Alexander, Marc D.; Craig, Gregory L.; Berezny, Nicholas; Wickramasinghe, Viresh (Proceedings of the SAFE Symposium, 2014)

Coarse “split and lump” bilingual language models for richer source information in SMT - Darlene, Stewart; Roland, Kuhn; Eric, Joanis; George, Forster (Proceedings of the Eleventh Conference of the Association for Machine Translation in the Americas (AMTA), 2014, 2014)
Recently, there has been interest in automatically generated word classes for improving sta- tistical machine translation (SMT) quality: e.g, (Wuebker et al, 2013). We create new mod- els by replacing words with word classes in features applied during decoding; we call these “coarse models”. We find that coarse versions of the bilingual language models (biLMs) of (Niehues et al, 2011) yield larger BLEU gains than the original biLMs. BiLMs provide phrase-based systems with rich contextual information from the source sentence; because they have a large number of types, they suffer from data sparsity. Niehues et al (2011) miti- gated this problem by replacing source or target words with parts of speech (POSs). We vary their approach in two ways: by clustering words on the source or target side over a range of granularities (word clustering), and by clustering the bilingual units that make up biLMs (bitoken clustering). We find that loglinear combinations of the resulting coarse biLMs with each other and with coarse LMs (LMs based on word classes) yield even higher scores than single coarse models. When we add an appealing “generic” coarse configuration chosen on English > French devtest data to four language pairs (keeping the structure fixed, but providing language-pair-specific models for each pair), BLEU gains on blind test data against strong baselines averaged over 5 runs are +0.80 for English > French, +0.35 for French > English, +1.0 for Arabic > English, and +0.6 for Chinese > English.
Keywords: Aluminum; Computational linguistics; Computer aided language translation; Speech transmission; Syntactics Automatically generated; Bilingual language model; Coarse models; Contextual information; Language pairs; Parts of speech; Statistical machine translation; Word clustering

Age-related differences in heat loss capacity occur under both dry and humid heat stress conditions - Larose, Joanie; Boulay, Pierre; Wright-Beatty, Heather E.; Sigal, Ronald J.; Hardcastle, Stephen; Kenny, Glen P. (Medicine and Science in Sports and Exercise, 2014)
Recent reports show reductions in evaporative heat loss during exercise in hot dry conditions in adults as young as 40, with differences being more pronounced with advanced age. It remains unclear how changes in ambient humidity, which can alter the evaporative efficiency of sweating, may influence the extent to which impairments in heat dissipation occur.PURPOSE: To compare evaporative heat loss in 60 healthy, unacclimated males, 20 to 70 years old, during intermittent exercise in a hot-dry (35°C, 20% relative humidity [RH]) and hot-humid (35°C, 60% RH) environment.METHODS: Participants performed four 15-min bouts of cycling at a rate of heat production equal to 400 W, interspersed with 15-min recovery periods in both environments. Direct calorimetry measured evaporative heat loss (HE) and dry heat exchange while indirect calorimetry measured metabolic heat production. The cumulative change in body heat content was measured as the temporal summation of heat production and total heat loss.RESULTS: HE was reduced by 17, 18, 21, 25 and 20% in males 20-30 (n=12), 40-44 (n=12), 45-49 (n=12), 50-54 (n=12) and 55-70 (n=12) years old (all P<0.001), respectively, during exercise in the hot-humid versus hot-dry environment. HE was also reduced between the hot-humid and hot-dry conditions in males 50-54 (-14%, P<0.001) and 55-70 years old (-11%, P=0.016) during recovery. During exercise in the humid heat stress condition, HE was greater in males 20-30 years old compared to males 45-49 (P=0.012), 50-54 (P=0.002) and 55-70 (P=0.002) years old. HE was also greater in males 40-44 years old compared to males 50-54 (P=0.029) and 55-70 years old (P=0.024) in the hot-humid condition. Body heat storage in the hot-humid condition was greater than in the hot-dry condition across age groups (P<0.001). Young males stored less heat in the hot-dry environment than males 40-70 years old (all P<0.005), and in the hot-humid condition compared to males 45-70 years old (all P<0.010).CONCLUSION: We show that middle-aged and older males have reduced evaporative cooling capacity, and therefore store more heat, than young males during exercise in both hot-dry and hot-humid environmental conditions. This Project was funded by research grants provided by the Workplace Safety and Insurance Board (Ontario) and the Canadian Institutes of Health Research.

Increased air velocity reduces young and older males’ thermal strain similarly despite humidity and clothing - Kenny, Glen P.; Hardcastle, Stephen G.; Larose, Joanie; Boulay, Pierre; Wright-Beatty, Heather (Medicine and Science in Sports and Exercise, 2014)
During exercise in dry heat, older adults have a lower evaporative heat loss capacity than younger adults when full evaporation is permitted, potentially putting older workers at greater risk for heat related injuries. However, it is unknown how increased air velocity alters the thermoregulatory responses when evaporative heat loss is restricted (i.e., high humidity, clothing insulation), and whether age-related differences in thermoregulation remain evident under such conditions.PURPOSE: To examine the heat stress responses of young and older males during intermittent exercise in humid heat under two levels of air velocity which modify the level of evaporative cooling.METHODS: Under 0.5 (Low) and 3.0 m/s (High) air velocity, 10 young (Mean±SE; Y: 24±1 yrs) and 10 older (O: 59±1 yrs) active males, matched for body surface area, cycled 4 x 15 min (15 min rest, 30 min final rest) at a fixed rate of heat production (400 W) wearing coveralls in humid heat (35°C, 60% relative humidity). Rectal (Tre) and visceral (Tvisc) temperatures, heart rate (HR), and local sweat rate (LSR) on the forearm were measured continuously.RESULTS: At the end of the 4th exercise bout, no age-related differences were observed between the low and high air velocity conditions for Tre (Low: Y = 38.28±0.11, O = 38.31±0.08; High: Y = 37.94±0.08, O = 37.87±0.08°C), Tvisc (Low: Y = 38.36±0.13, O = 38.26±0.07; High: Y = 37.93±0.10, O = 37.87±0.11°C), % of max HR (Low: Y = 79.9±2.8, O = 77.3±1.2; High: Y = 67.6±2.6, O = 72.4±2.2%), or LSR (Low: Y = 1.20±0.10, O = 1.17±0.10; High: Y = 1.15±0.11, O = 1.10±0.11 mg·min-1·cm-2). For both Young and Older males, Tre, Tvisc, HR, and LSR were reduced during the High compared to Low air velocity condition.CONCLUSION: Following moderate intensity intermittent exercise in humid heat wearing work coveralls, young and older males showed similar levels of thermal and cardiovascular strain under Low and High air velocity levels. Increased air velocity reduced the thermal and cardiovascular strain to a similar extent in both young and older males. This Project was funded by research grants provided by the Workplace Safety and Insurance Board (Ontario), Natural Sciences and Engineering Research Council of Canada, Canada Foundation for Innovation (all G.P. Kenny), MITACS Accelerate (H.E. Wright).

Similar thermal strain reductions and cognitive function with age and air velocity during heat stress - Wright-Beatty, Heather E.; Hardcastle, Stephen G.; Keillor, Jocelyn M.; Larose, Joanie; Boulay, Pierre; Kenny, Glen P. (Medicine and Science in Sports and Exercise, 2014)
Older adults may be at greater risk for occupational injuries given their reduced evaporative heat loss when full sweat evaporation is permitted, leading to greater thermal strain and potentially cognitive decrements. However, age-related differences in heat loss capacity may not be as evident under conditions which restrict evaporative heat loss (i.e., humidity, clothing), subsequently increasing the risk in all workers. Although industries increase air circulation in attempts to reduce thermal strain, the effectiveness in reducing physiological strain and cognitive function impairments are unknown.PURPOSE: To examine the effects of increased air velocity during exercise in humid heat on the capacity and rate of information processing and attention of young versus older adults.METHODS: Nine young (Mean±SE; Y: 24±1 yrs) and 9 older (O: 59±1 yrs) males, matched for body surface area and wearing coveralls, cycled 4 x 15 min (15 min rest) at a fixed rate of heat production (400 W) in humid heat (35°C, 60% relative humidity) under 0.5 (Low) and 3.0 m/s (High) air velocity. Rectal temperature (Tre) and heart rate (HR) were measured continuously. At baseline (PRE), immediately following exercise (POST), and the end of the 30 min final recovery (END), participants performed a Paced Auditory Serial Addition Task (PASAT, 2s).RESULTS: Tre and HR were similar between age groups in Low and High, however were greater in Low (Tre POST: Y = 38.30±0.12, O = 38.31±0.08°C) than High (Tre POST: Y = 37.96±0.09, O = 37.84±0.09°C) for both groups. PASAT # of correct responses was similar between Y (POST: Low = 49±3, High = 51±3) and O (POST: Low = 46±5, High = 47±4) and conditions. When scored relative to age norms, no differences were observed between groups or conditions for z-scores or percentile (Low: Y = 69.0±7.5, O = 69.8±9.7; High: Y = 72.7±6.3, O = 73.0±8.3%).CONCLUSION: Preliminary data indicate that while cognitive decrements in attention and working memory were not observed following intermittent exercise in humid heat or altered air velocity, increased air velocity reduced thermal strain equally in young and older males. This Project was funded by research grants provided by the Workplace Safety and Insurance Board (Ontario), Canada Foundation for Innovation-Leaders Opportunity Fund (G.P. Kenny), MITACS Accelerate (H.E. Wright).

Mismatch negativity and reorienting negativity demonstrated during EEG flight trials - Keillor, J.; Atluri, S.; Petley, L.; Kissmann, P.; Craig, G.; Araujo, J.; Wright-Beatty, Heather; Wolde, M. (Aviation, Space, and Environmental Medicine, 2014)
INTRODUCTION: A physiological monitoring capability was integrated into a National Research Council Canada Convair 580 research aircraft in order to investigate pilot workload and fatigue. The goal of the project was to develop an objective means of evaluating pilot workload and alertness that does not interfere with a pilot’s fl ight task. To this end, an electroencephalography (EEG) system was interfaced with the aircraft communication system to present auditory stimuli to the pilot’s headset so that the resultant event-related potentials (ERPs) could be analyzed. The result was a precisely-timed technique for evaluating the cognitive processing of an ignored auditory information stream in a fl ying pilot. METHODS: An auditory oddball task was used such that 100 ms standard (1000Hz) and deviant (1500Hz) tones were presented at a rate of one per second. Deviant tones represented 10% of the tone sequence, and were delivered at random, unpredictable times. RESULTS: Across a series of 15-minute fl ight segments, characteristic ERP sensory components (P1, N1, and P2) were observed in response to the standard tones. More importantly, when the event-related potentials to standard and deviant tones were compared, a signifi cant mismatch negativity (MMN) with a classic frontocentral distribution was observed. A statistically signifi cant reorienting negativity (RON) was also observed, suggesting a reorienting to the primary fl ight task following distraction by the deviant tones. DISCUSSION: Mismatch and reorienting negativity are small ERP components that can be diffi cult to detect in environments that are high in electromagnetic noise. The demonstration of reliable MMN and RON effects during actual fl ight represents an important step in the development of pilot alertness monitoring techniques.

Identification of microRNAs involved in Alzheimer's progression using a rabbit model of the disease - Liu, Qing Yan; Chang, Marilyn N Vera; Lei, Joy X.; Koukiekolo, Roger; Smith, Brandon; Zhang, Dongling; Ghribi, Othman (American Journal of Neurodegenerative Disease, 2014)
In a collaboration involving 11 groups with research interests in cerebral amyloid angiopathy (CAA), we used a two-stage process to develop and in turn validate a new consensus protocol and scoring scheme for the assessment of CAA and associated vasculopathic abnormalities in post-mortem brain tissue. Stage one used an iterative Delphi-style survey to develop the consensus protocol. The resultant scoring scheme was tested on a series of digital images and paraffin sections that were circulated blind to a number of scorers. The scoring scheme and choice of staining methods were refined by open-forum discussion. The agreed protocol scored parenchymal and meningeal CAA on a 0-3 scale, capillary CAA as present/absent and vasculopathy on 0-2 scale, in the 4 cortical lobes that were scored separately. A further assessment involving three centres was then undertaken. Neuropathologists in three centres (Bristol, Oxford and Sheffield) independently scored sections from 75 cases (25 from each centre) and high inter-rater reliability was demonstrated. Stage two used the results of the three-centre assessment to validate the protocol by investigating previously described associations between APOE genotype (previously determined), and both CAA and vasculopathy. Association of capillary CAA with or without arteriolar CAA with APOE ε4 was confirmed. However APOE ε2 was also found to be a strong risk factor for the development of CAA, not only in AD but also in elderly non-demented controls. Further validation of this protocol and scoring scheme is encouraged, to aid its wider adoption to facilitate collaborative and replication studies of CAA.
Keywords: angiopathy; amyloid; dementia; Delphi; validation; APOE; CAA; consensus; parenchymal; meningeal

Standardized assessment of static neck strength capacity for representative in-flight head postures of CAF helicopter aircrew - Gilchrist, I.; Wright-Beatty, H.; Keillor, J.; Pelland, L. (Canadian Institute for Military and Veteran Health Research, 2014)
Introduction: The capacity of the human neck to generate static moments of force is key in maintaining the stability of the cervical spine (c-spine) under various conditions of dynamic external load application. Compared to the lower cspine (T ₁), the upper c-spine (C ₀-C ₁) has a decreased capacity to generate moments, and is therefore more susceptible to injury, as forces that exceed this maximal capacity will be borne by passive tissues (ligaments and vertebrae). Deviations in head posture from neutral will modify the balance of muscle moments, increasing the risk of upper cspine injury. The aim of this study was to quantify the effects of seven postures, typically held by helicopter aircrew during in-flight, on the static strength capacity of the upper and lower cspine of Canadian Armed Forces (CAF) helicopter aircrew. Methods: Seven postures were identified by measuring head-neck-torso angles, relative to self-selected neutral, of a CAF helicopter pilot seated in a Bell-412 helicopter: 1) Left 20˚ rotation, 20˚ flexion, 2) 0˚ rotation, 0˚ flexion; 3 and 4) left and right 45˚ rotation, respectively, 0˚ flexion; 5) left 45˚ rotation, 20˚ flexion; 6) 0˚ rotation, 10˚ extension; 7) right 45˚ rotation, 10˚ extension. Two male CAF CH-146 helicopter pilots (36 and 49 years old) performed one maximal voluntary isometric muscle effort (MVIE) in the seven head-on-neck postures. MVIEs were measured using a custom-modified Multi-Cervical Unit (2048Hz; BTE Technologies). Absolute peak external force (N) was measured using a thin-beam strain gauge load cell. Anatomical landmarks were digitized to establish reference points at C ₀-C ₁ and T ₁; (30Hz; Optotrak). Resultant peak moments (Mpeak, Nm) were calculated as the cross product of the external force and the distance from the load cell to the anatomical reference points. Results: Normalized T ₁ Mpeak relative to neutral (posture 2) was 0.85, 1.00, 0.87, 0.92, 0.53, 0.63, and 0.40 (postures 1-7, respectively). Magnitude of Mpeak generated at C ₀-C ₁ was 41% compared to T ₁. Head postures 3 and 5 elicited differential C ₀-C ₁ vs. T ₁ Mpeak ratios of 47% vs. 34% and 44% vs. 26% (pilot 1 vs. 2, respectively). Conclusions: Head postures that combine sagittal head flexion or extension with axial rotation decrease the moment generating capacity and increase the vulnerability of the upper c-spine to injury. Static neck strength assessment in representative in-flight postures may help to identify pilots who may be at risk of developing flight-related neck pain, and identify postures that may increase the risk of injury

Development of a rapid multiplex PCR assay to genotype pasteurella multocida strains by use of the lipopolysaccharide outer core biosynthesis locus - Harper, Marina; John, Marietta; Turnic, Conny; Edmundsa, Mark; St. Michael, Frank; Adler, Ben; Blackall, P. J.; Cox, Andrew D.; Boyce, John D. (Journal of Clinical Microbiology, 2014)
Pasteurella multocida is a Gram-negative bacterial pathogen that is the causative agent of a wide range of diseases in many animal species, including humans. A widely used method for differentiation of P. multocida strains involves the Heddleston serotyping scheme. This scheme was developed in the early 1970s and classifies P. multocida strains into 16 somatic or lipopolysaccharide (LPS) serovars using an agar gel diffusion precipitin test. However, this gel diffusion assay is problematic, with difficulties reported in accuracy, reproducibility, and the sourcing of quality serovar-specific antisera. Using our knowledge of the genetics of LPS biosynthesis in P. multocida, we have developed a multiplex PCR (mPCR) that is able to differentiate strains based on the genetic organization of the LPS outer core biosynthesis loci. The accuracy of the LPS-mPCR was compared with classical Heddleston serotyping using LPS compositional data as the “gold standard.” The LPS-mPCR correctly typed 57 of 58 isolates; Heddleston serotyping was able to correctly and unambiguously type only 20 of the 58 isolates. We conclude that our LPS-mPCR is a highly accurate LPS genotyping method that should replace the Heddleston serotyping scheme for the classification of P. multocida strains.

Characterization of phospholipid-encapsulated gold nanoparticles: a versatile platform to study drug delivery and cellular uptake mechanisms - Wang, Meijing; Petersen, Nils O. (Canadian Journal of Chemistry, 2014)
The data presented in this work aim to provide a comprehensive characterization of lipid-coated gold nanoparticles. We show that it is possible to envelop gold nanoparticles with a coating of lipids during the formation of the gold nanoparticles, that the gold in these lipid-coated gold nanoparticles is crystalline and the size and shape can be controlled by the reaction conditions (within limits), that the lipid coating corresponds to a thickness consistent with the formation of a bilayer, that the bilayer can include fluorescent probes that, while quenched, can be used to trace the fate of the gold nanoparticles in cellular systems, that their surface charge, and hence their overall stability in solution, is influenced by the lipid coating, and that while some lipid dyes may exchange among the particles, they are sufficiently stable to exchange to permit their use as tracers in cell studies. We believe this is the most comprehensive characterization of these systems to date.
Keywords: gold nanoparticles, phospholipid, drug delivery

Cationic poly(2-aminoethylmethacrylate) and poly(N-(2-aminoethylmethacrylamide) modified cellulose nanocrystals: synthesis, characterization, and cytotoxicity - Hemraz, Usha D.; Campbell, Kendra A.; Burdick, James S.; Ckless, Karina; Boluk, Yaman; Sunasee, Rajesh (Biomacromolecules, 2014)
Cellulose nanocrystals (CNCs) continue to gain increasing attention in the materials community as sustainable nanoparticles with unique chemical and mechanical properties. Their nanoscale dimensions, biocompatibility, biodegradability, large surface area, and low toxicity make them promising materials for biomedical applications. Here, we disclose a facile synthesis of poly(2-aminoethylmethacrylate) (poly(AEM)) and poly(N-(2-aminoethylmethacrylamide) (poly(AEMA)) CNC brushes via the surface-initiated single-electron-transfer living radical polymerization technique. The resulting modified CNCs were characterized for their chemical and morphological features using a combination of analytical, spectroscopic, and microscopic techniques. Zeta potential measurements indicated a positive surface charge, and further proof of the cationic nature was confirmed by gold deposition as evidenced by electron microscopy. The cytotoxicity of these cationic modified CNCs was evaluated utilizing a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in two different cell lines, J774A1 (mouse monocyte cells) and MCF-7 (human breast adenocarcinoma cells). The results indicated that none of the cationic modified CNCs decreased cell viability at low concentrations, which could be suitable for biomedical applications.

Bimodal dwell-fatigue Weibull distribution of forged titanium IMI 834 - Toubal, Lofti; Bocher, Philippe; Moreau, André (International Journal of Damage Mechanics, 2014)
This study addresses cumulative damage and its evolution during the cold dwell fatigue of a near-α titanium alloy. An experimental study was undertaken to examine the evolution of life, strain, strength and damage of 13 titanium IMI 834 samples cut from a single disk forging. The samples were tested in the same dwell-fatigue loading conditions. In the dwell phase, the load is maintained at 80% of ultimate tensile strength (824 MPa, 90% of yield strength) for 30 s. The secant Young’s modulus and inelastic strain at minimum load were measured in order to document the evolution of the irreversible damage against the number of cycles for all specimens. Experimental observations show significant differences in dwell-fatigue life and damage behavior. This mechanical analysis and an analysis of the cumulative Weibull reliability distribution suggest a bimodal dwell-fatigue failure process. Some features of the mechanical behavior can be used to sort the samples according to each of the two failure modes and improve the reliability of the fatigue test campaign.

Articulated statistical shape models of the spine - Boisvert, Jonathan (Spinal Imaging and Image Analysis, 2014)
The spine is a complex assembly of rigid vertebrae surrounded by various soft tissues (ligaments, spinal cord, intervertebral discs, etc.). Its motion for a given individual and its shape variations across a population are greatly influenced by this fact. We show in this chapter how statistical shape models can be constructed, used, and analyzed while taking into account the articulated nature of the spine. We begin by defining what articulated models are and how they can be extracted from existing 3D reconstructions or segmented models. As an example, we use data from scoliotic patients that have been reconstructed in 3D using bi-planar radiographs. Articulated models naturally belong to a manifold where conventional statistical tools are not applicable. In this context, a few key concepts allowing the computation of statistical models on Riemannian manifolds are presented. When properly visualized, the resulting statistical models can be quite useful to analyze and compare the shape variations in different groups of patients. Two different approaches to visualization are demonstrated graphically. Finally, another important use of statistical models in medical imaging is to constrain the solution of inverse problems. Articulated models can readily be used in this context, we illustrate this in the context of 3D model reconstruction using partial data. More precisely, we will show the benefits of integrating a simple regularization term based on articulated statistical models to well known algorithms.
Keywords: Biomedical Engineering; Image Processing and Computer Vision; Imaging / Radiology

A general framework to generate sizing systems from 3D motion data applied to face mask design - Bolkart, Timo; Bose, Prosenjit; Shu, Chang; Wuhrer, Stefanie (2014 2nd International Conference on 3D Vision, 2014)
For the design of mass-produced wearable objects for a population it is important to find a small number of sizes, called a sizing system, that will fit well on a wide range of individuals in the population. To obtain a sizing system that incorporates the shape of an identity along with its motion, we introduce a general framework to generate a sizing system for dynamic 3D motion data. Based on a registered 3D motion database a sizing system is computed for task-specific anthropometric measurements and tolerances, specified by designers. We generate the sizing system by transforming the problem into a box stabbing problem, which aims to find the lowest number of points stabbing a set of boxes. We use a standard computational geometry technique to solve this, it recursively computes the stabbing of lower-dimensional boxes. We apply our framework to a database of facial motion data for anthropometric measurements related to the design of face masks. We show the generalization capabilities of this sizing system on unseen data, and compute, for each size, a representative 3D shape that can be used by designers to produce a prototype model.

Biocomposites and bioplastics for automotive PA and ABS based biocomposites - Mihai, Mihaela; Stoeffler, Karen; Bravo, Victor; Legros, Nathalie (2014)

Radio-continuum study of Large Magellanic Cloud supernova remnant J0509-6731 - Bozzetto, L. M.; Filipovi , M. D.; Urosevic, D.; Kothes, R.; Crawford, E. J. (Monthly Notices of the Royal Astronomical Society, 2014)
We present a detailed study of Australia Telescope Compact Array observations (λ = 20, 13, 6 and 3 cm) of supernova remnant (SNR) J0509−6731 in the Large Magellanic Cloud. The remnant has a ring morphology with brightened regions towards the south-western limb. We also find a second brightened inner ring which is only seen in the radio continuum. The SNR is almost circular, with a diameter ranging from 7 to 8 pc, and a steep radio spectral index between 36 and 3 cm of α = −0.73 ± 0.02, which is characteristic of younger SNRs. We also report detection of radially orientated polarization across the remnant at 6 cm, with a mean fractional polarization level of P ≅ (26 ± 13) per cent. We find the magnetic field (∼168 μG) and Σ–D (Σ = 1.1 × 10⁻¹⁹ W m⁻² Hz⁻¹ sr⁻¹, D = 7.35 pc) to be consistent with other young remnants.
Keywords: Polarization; Supernova remnants; Magellanic Clouds; Radio continuum

Initial experimental and theoretical investigation of solar molten media methane cracking for hydrogen production - Paxman, D.; Trottier, S.; Nikoo, M.; Secanell, M.; Ordorica-Garcia, G. (Energy Procedia, 2014)
Previous work assessed the fundamental technical and market risks associated with the development and deployment of solar fuels technology in Alberta. It identified methane cracking in solar-molten media as the hydrogen production technology featuring the best combination of technical risk, market acceptance, and breakthrough potential of all the techniques covered in the study. Alberta Innovates – Technology Futures (AITF) plans to advance the technology from a conceptual stage to a proof-of concept over a span of 4 years. The ultimate goal is to design, build and test a prototype solar receiver/reactor in a suitable solar simulator. The paper outlines the activities to date concerning the initial bench-scale testing of methane cracking in molten media at temperatures ranging from 1023 to 1373 K. The design and construction of an experimental apparatus used to establish the fundamental thermo-chemical performance of the process is presented, along with preliminary results and lessons from the first testing campaign. A transient, non-isothermal, preliminary mathematical model of a reacting bubble within the molten metal has been developed using MATLAB. The model accounts for the chemical reactions, diffusion of the gases in the bubble and heat transfer from the molten metal to the reacting gases. The model can be used to predict the minimum bubble residence time needed to achieve a given hydrogen yield. The simulation tool will be used to numerically estimate methane conversions in the reactor at various conditions.
Keywords: Methane cracking; Hydrogen production; Direct contact pyrolysis; Methane decomposition; Molten media; Liquid metals

DADAR: a new situational awareness platform for data analysis, detection and response - Carter, Dave; Martin, Joel D. (Online Journal of Public Health Informatics, 2014)
We introduce our new DADAR (Data Analysis, Detection, And Response) syndromic surveillance platform.
Keywords: surveillance; situational awareness; data fusion; outbreak detection; informatics

Diagnostics and prognostics algorithms for an aircraft accessory gearbox - Rezaei, Aida; Dadouche, Azzedine (5th World Tribology Congress, 2014)

Design of complex optical coatings - Verly, P. G. (Optical Thin Films and Coatings, 2014)
Thin film design is loosely subdivided in two categories: refinement and synthesis, where synthesis refers to different ways of generating potentially complex solutions virtually from scratch, without the need for special starting designs. This chapter first reviews several successful thin film synthesis approaches. It then discusses the desensitization of the solutions to manufacturing errors and gives several examples of hybrid situations outside the classical framework, where the interference in the coating is not the only concern or where the geometry of the problem significantly complicates the modeling.
Keywords: Thin film design; Thin film synthesis; Error desensitization; Waveguide facet coating; Resonant grating coating; Solar cell design

Analysis of the stress-free interplanar spacing during solution heat treatment of 319 Al alloy engine blocks via in-situ neutron diffraction - Lombardi, Anthony; Sediako, Dimitry; Ravindran, Comondore (Ravi); Mackay, Robert (Materials Science & Technology Conference and Exhibition 2013, 2014)
Aluminum alloy engine blocks have successfully replaced ferrous materials in order to maximize weight savings and improve vehicle fuel efficiency. However, the development of an optimal heat treatment process is required to improve engine block casting integrity and prevent potential problems such as in-service cylinder distortion. Optimization of heat treatment parameters requires an in-depth study to determine how residual stresses are relieved with time during solution heat treatment. In order to perform this analysis, however, in-situ neutron diffraction must first be carried out on stress-free samples of the same composition and processing history as the engine blocks to account for factors such as thermal expansion and changes in lattice parameter due to dissolution of secondary phases. The results from this study suggest that thermal expansion caused the largest change in d0 spacing, while prolonged exposure to solution temperatures of 470 and 500 °C did not cause significant changes in d0.
Keywords: Engine blocks; Heat treatment parameters; In-situ neutron diffraction; Interplanar spacings; Vehicle fuel efficiencies; Engine cylinders

A quantum mechanical approach to establishing the magnetic field orientation from a maser Zeeman profile - Green, J. A.; Gray, M. D.; Robishaw, T.; Caswell, J. L.; McClure-Griffiths, N. M. (Monthly Notices of the Royal Astronomical Society, 2014)
Recent comparisons of magnetic field directions derived from maser Zeeman splitting with those derived from continuum source rotation measures have prompted new analysis of the propagation of the Zeeman split components, and the inferred field orientation. In order to do this, we first review differing electric field polarization conventions used in past studies. With these clearly and consistently defined, we then show that for a given Zeeman splitting spectrum, the magnetic field direction is fully determined and predictable on theoretical grounds: when a magnetic field is oriented away from the observer, the left-hand circular polarization is observed at higher frequency and the right-hand polarization at lower frequency. This is consistent with classical Lorentzian derivations. The consequent interpretation of recent measurements then raises the possibility of a reversal between the large-scale field (traced by rotation measures) and the small-scale field (traced by maser Zeeman splitting).
Keywords: Magnetic fields; Masers; Polarization; Radiative transfer

Asymmetric mutations in the tetrameric R67 dihydrofolate reductase reveal high tolerance to active-site substitutions - Ebert, Maximilian C. C. J. C.; Morley, Krista L.; Volpato, Jordan P.; Schmitzer, Andreea R.; Pelletier, Joelle N. (Protein Science, 2014)
Type II R67 dihydrofolate reductase (DHFR) is a bacterial plasmid-encoded enzyme that is intrinsically resistant to the widely-administered antibiotic trimethoprim. R67 DHFR is genetically and structurally unrelated to E. coli chromosomal DHFR and has an unusual architecture, in that four identical protomers form a single symmetrical active site tunnel that allows only one substrate binding/catalytic event at any given time. As a result, substitution of an active-site residue has as many as four distinct consequences on catalysis, constituting an atypical model of enzyme evolution. Although we previously demonstrated that no single residue of the native active site is indispensable for function, library selection here revealed a strong bias toward maintenance of two native protomers per mutated tetramer. A variety of such “half-native” tetramers were shown to procure native-like catalytic activity, with similar KM values but kcat values 5- to 33-fold lower, illustrating a high tolerance for active-site substitutions. The selected variants showed a reduced thermal stability (Tm ∼12°C lower), which appears to result from looser association of the protomers, but generally showed a marked increase in resilience to heat denaturation, recovering activity to a significantly greater extent than the variant with no active-site substitutions. Our results suggest that the presence of two native protomers in the R67 DHFR tetramer is sufficient to provide native-like catalytic rate and thus ensure cellular proliferation.
Keywords: Trimethoprim resistance; Combinatorial mutations; Thermostability; Active site engineering; Homotetramer

The design of building elements for the sound insulation of mobile studio spaces - Mahn, J. (7th Forum Acusticum 2014, 2014)
The city of Christchurch, New Zealand currently lacks performance studios where performers can practice due to the widespread damage caused by the 2011 earthquake. However, there are large areas of vacant lots in the city center where buildings have been removed, but redevelopment work has yet to begin. To solve the problem of the lack of available studio spaces and to take advantage of the available open spaces, a mobile building known as project BeatBox was proposed to be built in one of the available, vacant lots. The mobile building includes three studio spaces as well as office spaces. A stipulation for the building design was that it needed to be possible to disassemble the entire building so that it can be transported to a new site and reconstructed when the original building site is ready to be redeveloped. Additional stipulations included stringent sound insulation requirements between the studios, between the studios and the offices and between the studios and the outside. A novel design for the space was proposed to meet the airborne and impact sound insulation requirements based on prediction models. The final design was a compromise between the acoustic, earthquake, fire and structural requirements. The building design is presented and the measured sound insulation values of the studios are compared versus the original, predicted values.

Analysis on structure-borne sound transmission at junctions of solid wood double walls with continuous floors - Schoenwald, Stefan; Zeitler, Berndt; Sabourin, Ivan (7th Forum Acusticum 2014, 2014)
Structure-borne sound transmission across a cross-junction of double solid timber walls with a solid timber floor was analyzed in a recent research project. Both, the double walls as well as floor slab, were of so-called Cross Laminated Timber (CLT). The floor slab was continuous across the junction for structural reasons and thus, formed a sound bridge between the elements of the double wall. To gain a better understanding of the contributions of sound transmission between the wall and floor elements from the different possible paths, a thorough analysis was conducted. Hereby, direct sound transmission through, and radiation efficiencies of, the CLT elements were measured in a direct sound transmission facility; as well as, structure-borne sound transmission between CLT elements was measured on a junction mock-up. The experimental data was used as in-put data and for validation of the engineering model of EN 12354/ISO 15712 for the prediction of flanking sound insulation in buildings. The test procedures, analysis and results of this research project are presented here.

Cross-lingual discourse relation analysis: a corpus study and a semi-supervised classification system - Li, Junyi Jessy; Carpuat, Marine; Nenkova, Ani (25th International Conference on Computational Linguistics, 2014)
We present a cross-lingual discourse relation analysis based on a parallel corpus with discourse information available only for one language. First, we conduct a corpus study to explore differences in discourse organization between Chinese and English, including differences in information packaging, implicit/explicit discourse expression divergence, and discourse connective ambiguities. Second, we introduce a novel approach to learning to recognize discourse relations, using the parallel corpus instead of discourse annotation in the language of interest. Our resulting semi-supervised system reaches state-of-art performance on the task of discourse relation detection, and outperforms a supervised system on discourse relation classification.

Compression moulding of stiffened brackets using randomly-oriented strands thermoplastic composites - Leblanc, D.; Levy, A.; Hubert, P.; Roy, S.; Yousefpour, A. (CAMX 2014, 2014)
Randomly-oriented strands (ROS) composites offer the possibility to mould complex parts with fast processing cycles. This material is ideal for small complex parts such as brackets and hinges where varying wall thickness, tight radii and rib features are common. In this paper, the manufacturing of a ROS composite bracket with a rib feature is presented. The bracket was designed to have similar stiffness to that of an aluminum angle bracket. A four-point bending test method (ASTM D6415) was used to quantify the stiffness of the ROS and aluminum parts. Per weight basis, the ROS composite part was 19% stiffer than the aluminum bracket. The main findings show the use of ROS as a good material candidate to mould complex parts which could inherently replace typical metallic brackets that are commonly used in aircrafts.

Simulation of shaped charge jet formation using ALE element formulation - Downes, D.; Bouamoul, A.; Ensan, M. N. (Proceedings : 28th International Symposium on Ballistics, 2014)
This paper describes recent progress on numerical simulation of shaped charges (SC) using an Arbitrary-Lagrangian-Eluerian (ALE) framework. The framework consists of simulating the formation, elongation and possible fragmentation of the liner. The aforementioned stages of SC development were modeled using the ALE element formulation in the LS-DYNA Finite Element Analysis software. The simulation incorporates features such as Arbitrary-Lagrangian-Eulerian-Multi-Material-Group, the High Explosive Burn, the Johnson-Cook constitutive material model, and the Jones Wilkins-Lee and Mei-Gruneisen Equations-of-State. The model provides a robust means of handling the large amount of deformation present in SC jet formation and elongation. Results for a shaped charge with a 80-mm cone diameter are resented.

Key advantages of high performance lubricants for the manufacturing of powder metallurgy parts - Paris, Vincent; St-Laurent, Sylvain; Thomas, Yannig (Advances in powder metallurgy & particulate materials - 2014 : proceedings of the PM2014 World Congress on Powder Metallurgy & Particulate Materials, 2014)
In powder metallurgy, the usage of an admixed lubricant to aid the compaction and to ease the ejection of the green parts is most of the time unavoidable. Over the past years, many lubricant formulations which were either developed by metal powder producers or independent lubricant manufacturers were introduced to the market. All the while, some common powder metallurgy lubricants are still widely used in the industry, mostly due to the fact that their behaviour is well known and are also cost competitive. Nevertheless, the actual offering of high performance lubricants offers many advantages over the traditional lubricants. This paper offers a review of the major advantages of high performance lubricants over traditional formulations. The lubricants were evaluated in FC-0208 and FD-0208 steel powder compositions. Apparent density, flow rate, compressibility, ejection behaviour, surface finish and sintered properties were evaluated. It is demonstrated that high performance lubricants, despite their slightly higher cost compared to conventional lubricants, can offer net benefits to parts manufacturers. The lubricants were tested at equal concentrations (0.7% w/w) in order to offer a fair comparison and ease the process of selecting a given lubricant when designing new parts. Although great care was taken to insure all lubricants were tested equally, it is understood that some lubricants may perform better than described herein in other compaction conditions or with different powder formulations.

Using DNA microarray technology to monitor the distribution of antimicrobial resistance genes in Escherichia coli isolated from animal colibacillosis outbreaks - Badagliacca, Pietro; Masson, Luke; Tonelli, Alfreda; Migliorati, Giacomo; Harel, Josée (Microarrays: Principles, Applications and Technologies, 2014)
A customized DNA microarray was designed to detect Escherichia coli virulence genes in addition to Gram-negative genes conferring resistance to antimicrobials belonging to the aminoglycoside, β-lactam, tetracycline, sulfonamide, phenicol, and quinolone families as well as to rifampin, erythromycin, trimethoprim, olaquindox, quaternary ammonium compound resistant determinant genes, and mobile genetic elements such as class 1, 2, 3 integrons and transposon Tn21. This microarray was applied in the genotyping of two collection strains coming from colibacillosis outbreaks in rabbit and cattle facilities located in Italy and Iran, respectively. For each collection, the positive gene distribution and frequency per encoded enzyme or protein involved in antimicrobial resistance was first determined. Thereafter, strains positive for integrons were matched with the presence of transposon Tn21 (tnpM gene) in order to highlight the genetic potential of resistance (multi-resistance) transferability in the examined strains. Fourteen of 26 strains in our rabbit E. coli collection were positive for a class 1 integron, six of which were associated with the tnpM gene and multidrug resistance-related genes to the aminoglycoside, tetracycline, and sulfonamide-trimethoprim antimicrobial families, prevalently. Class 1 and/or class 2 and 3 integrons were also detected in 23 out of 51 strains in our cattle E. coli collection, 13 of which were also positive for tnpM gene. The presence of multiple drug resistance involving the aminoglycoside, tetracycline, and sulfonamide antimicrobial families are positively associated with this tnpM gene group. Moreover, strains having positive genes for integrons and transposons were also carriers, to a lesser extent, of class A and/or class C β-lactamase (11 strains) and quinolone (9 strains) resistant genes. The DNA microarray used in this chapter has proven to be a powerful tool in determining the genetic profile of antimicrobial resistance in E. coli field strains. The DNA microarray technology may be an appropriate technology for inclusion in antimicrobial resistance monitoring programs because of its adaptability to and ease of data collection for any particular monitoring program. Furthermore, this technology could be used to assess the effectiveness of antimicrobial use-reduction plans or in comparative studies between traditional and antibiotic-free animal production systems.

Residual surface undulations in the OEB after the termination of wave generation in shallow water - Zaman, Hasanat; Mak, Lawrence; Millan, Jim; McKay, Shane (National Research Council Canada, 2014)
During the generation of any wave in the tank we get relevant primary wave component along with bounded wave components if the incident primary wave has more than one frequency. Inevitably we also get interacted wave components, natural frequency components of the tank and other free waves. In this report the natural frequency energy components in the OEB were investigated using several cases of mono- and bi-chromatic waves in the tank. These natural frequency components were compared with the total energy and bounded wave energy measured in the tank. The reason of this investigation is to understand the extent of the natural frequency energy components of the tank of different modes in the measured wave data and also the damping rate of the residual surface undulation components in the tank with time. Results are shown for both monoand bi-chromatic waves. It is found that the primary frequency components are interacting with each other in different forms and wave energies are transferred to the interacted frequency bands. Also from the data, we observed that the natural frequency components for both longitudinal and transverse directions of the tank were too small compare to the primary wave components at least in the cases that we considered here.
Keywords: Wave damping in OEB; natural frequency; shallow water

Chasing the magic wear rate - Magel, E.; Kalousek, J.; Sroba, P. (Proceedings of the Second International Conference on Railway Technology: Research, Development and Maintenance, 2014)
The magic wear rate (MWR) is the rate of wear at which any rolling contact fatigue cracks that are in initial stages of development are removed either by natural or a combination of natural and artificial wear. It is a simple concept which recognizes that when there is little or no wear, the rail will usually fail as a result of contact fatigue, but when there is excessive wear, the life is unnecessarily wasted. The concept has direct application to rail maintenance practices, in particular rail grinding. This paper details the basic theory of the magic wear rate and includes a discussion about the impact of various influencing factors including wheel load, friction, track curvature and metallurgy. Application is made chiefly to rail grinding, although it is acknowledged that the principle also extends to wheel wear. Examples of current practices are given and a new approach to rail grinding is presented that would better target the magic wear rate.
Keywords: magic wear rate; rolling contact fatigue; rail grinding

Robust silicon waveguide polarization rotator with an amorphous silicon overlayer - Xiong, Yule; Xu, Dan-Xia; Schmid, Jens H.; Cheben, Pavel; Janz, Siegfried; Ye, Winnie N. (IEEE Photonics Journal, 2014)
We propose a robust polarization rotator based on the mode-evolution mechanism. The polarization rotation in a silicon wire waveguide is achieved by forming an amorphous silicon (a-Si) overlayer and an SiO₂ spacer on top of the waveguide. A strip pattern of a constant width is designed to be etched through the overlayer at a specific angle with respect to the Si waveguide. The asymmetry in the a-Si overlayer affects the waveguide mode by rotating the modal axis. This polarization rotator design is amenable to comparatively simple fabrication compatible with standard silicon photonic processing for integration. The length of the rotation section is 17 μm, and the broadband operation is achieved with a rotation efficiency higher than 90% for a wavelength range exceeding 135 nm. A maximum polarization rotation efficiency of 99.5% is predicted by calculation.
Keywords: Silicon waveguide; Polarization rotation; Amorphous silicon

Characterization of the vaginal microbiota of healthy Canadian women through the menstrual cycle - Chaban, Bonnie; Links, Matthew G.; Jayaprakash, Teenus Paramel; Wagner, Emily C.; Bourque, Danielle K.; Lohn, Zoe; Albert, Arianne Y. K.; van Schalkwyk, Julie; Reid, Gregor; Hemmingsen, Sean M.; Hill, Janet E.; Money, Deborah M. (Microbiome, 2014)
BACKGROUND: The vaginal microbial community plays a vital role in maintaining women’s health. Understanding the precise bacterial composition is challenging because of the diverse and difficult-to-culture nature of many bacterial constituents, necessitating culture-independent methodology. During a natural menstrual cycle, physiological changes could have an impact on bacterial growth, colonization, and community structure. The objective of this study was to assess the stability of the vaginal microbiome of healthy Canadian women throughout a menstrual cycle by using cpn60-based microbiota analysis. Vaginal swabs from 27 naturally cycling reproductive-age women were collected weekly through a single menstrual cycle. Polymerase chain reaction (PCR) was performed to amplify the universal target region of the cpn60 gene and generate amplicons representative of the microbial community. Amplicons were pyrosequenced, assembled into operational taxonomic units, and analyzed. Samples were also assayed for total 16S rRNA gene content and Gardnerella vaginalis by quantitative PCR and screened for the presence of Mollicutes by using family and genus-specific PCR. RESULTS: Overall, the vaginal microbiome of most women remained relatively stable throughout the menstrual cycle, with little variation in diversity and only modest fluctuations in species richness. Microbiomes between women were more different than were those collected consecutively from individual women. Clustering of microbial profiles revealed the expected groupings dominated by Lactobacillus crispatus, Lactobacillus iners, and Lactobacillus jensenii. Interestingly, two additional clusters were dominated by either Bifidobacterium breve or a heterogeneous mixture of nonlactobacilli. Direct G. vaginalis quantification correlated strongly with its pyrosequencing-read abundance, and Mollicutes, including Mycoplasma hominis, Ureaplasma parvum, and Ureaplasma urealyticum, were detected in most samples. CONCLUSIONS: Our cpn60-based investigation of the vaginal microbiome demonstrated that in healthy women most vaginal microbiomes remained stable through their menstrual cycle. Of interest in these findings was the presence of Bifidobacteriales beyond just Gardnerella species. Bifidobacteriales are frequently underrepresented in 16S rRNA gene-based studies, and their detection by cpn60-based investigation suggests that their significance in the vaginal community may be underappreciated.
Keywords: Vaginal microbiome; cpn60; Menstrual cycle; Bifidobacteriales; Bifidobacterium; Lactobacillus; Mollicutes; Mycoplasma; Yreaplasma; Gardnerella; Vaginal bacteria

Non-flammable electrolyte mixtures of ringed ammonium-based ionic liquids and ethylene carbonate for high voltage Li-ion batteries - Salem, Nuhu; Abu-Lebdeh, Yaser (Journal of the Electrochemical Society, 2014)
Three ionic liquids based on ringed ammonium cations with different ring sizes [seven: azepanium; six: piperidinium; five: pyrrolidinium] and imide anion mixed with ethylene carbonate, EC, have been evaluated as electrolytes in high voltage lithium-ion batteries. It is found that mixing the ionic liquids with ethylene carbonate gives electrolyte mixtures with lower viscosities, increased conductivities and improved electrochemical cathodic stability than the neat ionic liquids. The flammability and thermal stability of the electrolytes have been studied by open-cup flash point measurements and thermogravimetric analysis combined with Infrared and Mass Spectroscopy. It is found that the neat ionic liquids have good thermal stability above 300°C and no flammability compared to carbonate-based electrolyte but upon mixing with EC the mixture decomposes at temperature below 130°C but stays non-flammable. The electrolyte mixtures have been evaluated in Li/LiMn₁.₅Ni₀.₅O₄ (LMNO) and graphite/Li half cells and in the presence of fluoroethylene carbonate additive. Discharge capacities reaching 112–117 mAh.g⁻¹ and 280–293 mAh.g⁻¹ with coulombic efficiencies of 95% and 99% were obtained for graphite and LMNO, respectively, over 100 cycles at C/12.

Fell-field soil microbiology - Yergeau, Etienne (Antarctic Terrestrial Microbiology, 2014)
Only 0.33 % of the Antarctic land surface area is free of ice, with much of this area representing fell-field environments. Antarctic fell-fields are a type of tundra ecosystem that are generally nutrient-limited (especially N) and have a sparse cover of vegetation that is dominated by lichen or bryophytes, although dense vegetative cover and even vascular plants can be present in moister fell-field habitats. Environmental conditions are generally unfavourable in fell-field Antarctic environments, but these soils are spectacular in terms of the diversity of conditions that they offer for microbial life. This is reflected in the variety of microbial taxa and functions that can be found in these environments. Several factors were identified as having strong influences on the microbial communities inhabiting Antarctic fell-field soils, including water, temperature, plants, birds and pH. This chapter reviews microbiological studies that have been carried out in Antarctic fell-field soils.
Keywords: Microbial ecology; Bacteriology; Microbial genetics; Microbial genomics; Geology

A THz-bandwidth molecular memory for light - Bustard, Philip J.; England, Duncan G.; Lausten, Rune; Sussman, Benjamin J. (Frontiers in Optics 2014, 2014)
We demonstrate a memory for light based on storing photons in the vibrations of hydrogen molecules. The THz-bandwidth memory is used to store 100-fs pulses for durations up to ∼1ns, enabling ∼10⁴ operational time bins.

Numerical nonlinear analysis of subcritical Rayleigh-Bénard convection in a horizontal confined enclosure filled with non-Newtonian fluids - Benouared, Ouahiba; Mamou, Mahmoud; Messaoudene, Noureddine Ait (Physics of Fluids, 2014)
Non-Newtonian subcritical convection in a Rayleigh-Bénard configuration was investigated numerically, using rigid boundary conditions. The flow configuration consisted of a finite aspect ratio enclosure subject to a vertical temperature gradient, which was established by heating and cooling the lower and the upper walls by either a constant heat flux or by applying constant temperatures. The non-Newtonian fluid viscosity was modeled using the Carreau-Yasuda model. The convective flow was governed by the conservation equations, which were solved numerically using a finite difference method with a time-accurate scheme. For a shallow enclosure, when the walls were subject to constant heat fluxes, an asymptotic solution was derived assuming a parallel flow behavior. A comparison between the numerical and asymptotic solutions was performed. The effects of the controlling parameters, namely, the Rayleigh and the Prandtl numbers, and the fluid rheological parameters on the onset of subcritical convective flow were investigated. The threshold for the onset of subcritical convection was found to be well below the threshold of stationary convection and decreased considerably (with the fluid rheological parameters variation) as the fluid became more and more shear thinning. Depending on the governing parameters, steady and unsteady-periodic flow solutions were possible. Within a square enclosure with slip or no-slip vertical walls, maintaining the active walls at a constant heat flux or at constant temperature, the rheological subcritical flow behavior remained qualitatively the same, but led to different subcritical convection thresholds.
Keywords: Thermal convection; Shear thinning; Viscosity; Shear rate dependent viscosity; Boundary value problems

Quantitative analysis on the depletion rate of β-NiAl phases in MCrAlY coating - Kim, Daejin; Shin, Inhwan; Koo, Jaemean; Kim, Sangyoung; Seo, Dongyi; Kim, Jeongmin; Seok, Changsung (Journal of Mechanical Science and Technology, 2014)
In this study, a disk-shaped thermal barrier coating system for a gas turbine blade was isothermally aged at 1100°C for various times up to 800 h. The microstructures of the bond coat were observed by using an optical microscope for each aging condition. Diffusion of primary elements consisting of the bond coat was characterized by using electron probe microanalyzer mapping. Semi-quantitative analysis by using scanning electron microscopy energy-dispersive X-ray was insufficient to sense variations in the Al content within the bond coat according to exposure time. An area fraction of β-NiAl phases within the bond coat was calculated by image analysis, and a reasonable approach to estimate time for complete depletion of the Al-rich β-NiAl phase within the bond coat was suggested.
Keywords: β-NiAl depletion; Image analysis; Isothermal aging; TBC(thermal barrier coating); TGO(thermally grown oxide)

Molecular mechanisms of geniposide and genipin against Alzheimer’s disease - Liu, Jianhui; Yin, Fei; Guo, Lixia; Zhang, Junzeng; Zidichouski, Jeffrey (Bioactive Nutraceuticals and Dietary Supplements in Neurological and Brain Disease, 2014)
Alzheimer’s disease (AD) is characterized clinically by a progressive and gradual decline in cognitive function and neuropathologically by the presence of neuropil threads and specific neuronal and synapse losses in addition to postmortem confirmation of the presence of significantly elevated levels of neurofibrillary tangles and senile plaques. Accumulating evidence suggests that β-amyloid (Aβ) plays a crucial role and is purported to be a key factor involved in triggering a complex pathological cascade of events involved in the development and progression of AD. However, there is also accumulating evidence that other factors may be important in AD, such as oxidative stress, endoplasmic reticulum stress, loss of cholinergic neurons, neuroinflammation, genetic factors, and yet to be discovered factors that play important roles in the development and likely the rate of progression of AD. Geniposide and its aglycone genipin are the main bioactive constitutes of traditional Chinese medicine Gardenia jasminoides Ellis, and increasing evidence links geniposide and genipin to improvements in learning and memory in studies performed on animal models of AD. Moreover, both compounds appear to exert an array of neuroprotective-related effects that may be in turn linked to functional improvements that were observed. This review will focus upon and probe into the biological actions of geniposide and genipin, concentrating particularly on molecular mechanisms as related to their neuroprotective effects and actions.
Keywords: Alzheimer’s disease; β-amyloid (Aβ); Geniposide; Molecular mechanisms; Neuroprotection

Climate change and microbial populations - Yergeau, Etienne (Antarctic Terrestrial Microbiology, 2014)
By 2100, the mean air temperature at the Earth’s surface is predicted to increase by 1.4 °C to 5.8 °C, with a disproportionate effect at high altitudes and latitudes. This chapter reviews the currently available information regarding the responses of key microbial parameters, including diversity, community composition, abundance and functions, to climate change in Antarctic soils. For microorganisms inhabiting Antarctic soils, some insight has been gained by comparing microbial communities across latitudinal gradients, or through short-term laboratory incubations and field studies. Rapid responses of mosses, nematodes, soil algae, cyanobacteria, fungi, and bacteria have been observed in some Antarctic soils. Despite these interesting findings, it is difficult to specifically predict the effects of warming on Antarctic soil microorganisms. One reason is the extreme heterogeneity of soil habitats in this region, as they vary from moist eutrophic ornithogenic soils to nutrient- and water-limited Dry Valley soils. Climate change might have rapid and direct effects on soil microbes that are not otherwise limited, but the release of other limitations (e.g., water, nutrients) could be more important in several environments.
Keywords: Microbial ecology; Bacteriology; Microbial genetic; Microbial genomics; Geology

REVIEW: The rumen microbiome: composition, abundance, diversity, and new investigative tools - Chaucheyras-Durand, Frédérique; Ossa, Faisury (The Professional Animal Scientist, 2014)
Ruminants are able to degrade and use fibrous feed as a source of energy and nutrients because of the presence of complex anaerobic microbiota in the rumen, composed mainly of bacteria, fungi, and ciliate protozoa. Ruminal microorganisms play different roles in feed digestion and act synergistically to ferment plant structural and nonstructural carbohydrates and proteins. This review reports the latest assessment of microbiota diversity in the rumen ecosystem and summarizes the molecular techniques and the newly available “omic” technologies, based on DNA and RNA sequence analysis, which allow for new insights into the structure and functions of these complex microbial communities.
Keywords: Rumen; Microbiota; Ruminant digestion; Diversity; DNA-based technique; RNA-based technique

Floating ice and ice pressure challenge to ships - Kubat, Ivana; Fowler, David; Sayed, Mohamed (Snow and Ice-Related Hazards, Risks and Disasters, 2014)
The presence of floating ice in northern regions bears significant economic, environmental, and social implications. Navigation is one of the areas where the influence of floating ice is particularly evident. The history of ice threats to navigation and hardships experienced by early mariners are well known. At present, even with all the new technologies, ice can pose serious challenges. A major threat arises when ice around a ship starts to converge. The compression or ice pressure builds up if wind and water currents drive the ice cover against a land boundary. The ice cover compresses and ice accumulates to form ridges. If a ship is caught in such a situation, pressures on the hull will be high. Additionally, the ridges can introduce serious impediments to ship progress. Consequently, ice resistance would dramatically increase, and the ship can become beset. In extreme cases, ships can be damaged, and smaller vessels can be completely lifted onto the ice. To understand how ice interacts with ships, we must start with ice properties and characteristics of ice covers. Ice ridges, for example, may represent formidable obstacles to ships. The way those ridges form and their properties determine the level of resistance that ships may encounter. Although the effects of ice pressure are important over all Arctic and northern waters, the focus of this discussion is on the Canadian experience. The particular conditions that lead to ice pressure build-up and the impact on shipping at various specific locations in Canada are surveyed. The discussions conclude with a description of a Captain's experience in dealing with ice pressure on the Great Lakes.
Keywords: Ice pressure; Ice compression; Ice ridging; Shipping in ice; Vessel besetting

Flame response analysis of syngas - Gorski, Jan; Chishty, Wajid Ali; Johnson, Matthew (ASME Turbo Expo 2014: Turbine Technical Conference and Expo, 2014)
The motivation for the work comes from the requirement to assess the feasibility of using alternative fuels in lean-premixed land-based stationary gas turbine combustion systems. Lean-premixed systems are prone to combustion instability issues and the need is to determine how the use of alternative fuels would affect such instabilities. The paper presents the results of an acoustically-forced laminar flat flame study that was conducted to measure the influence of flow velocity oscillations on the response of syngas flames under various operating conditions and in comparison to natural gas flames. The results indicate that syngas concentration in a methane-syngas-air mixture significantly affects the flame response. On the other hand, the ratio of hydrogen-to-carbon monoxide in the syngas was found to have a negligible effect on the flame response for a fuel blend made up of 50% methane and 50% syngas. Flame liftoff distance and flame speed were found to be important parameters that govern the flame transfer function magnitude and resonant frequency for a thermally stabilized flat flame. The paper also presents insights into flame transfer function scaling based on a refined Strouhal definition.
Keywords: syngas; flames

Clarifying values, risk perceptions, and attitudes to resolve or avoid social conflicts in invasive species management - Estévez, Rodrigo A.; Anderson, Christopher B.; Pizarro, J. Cristobal; Burgman, Mark A. (Conservation Biology, 2014)
Decision makers and researchers recognize the need to effectively confront the social dimensions and conflicts inherent to invasive species research and management. Yet, despite numerous contentious situations that have arisen, no systematic evaluation of the literature has examined the commonalities in the patterns and types of these emergent social issues. Using social and ecological keywords, we reviewed trends in the social dimensions of invasive species research and management and the sources and potential solutions to problems and conflicts that arise around invasive species. We integrated components of cognitive hierarchy theory and risk perceptions theory to provide a conceptual framework to identify, distinguish, and provide understanding of the driving factors underlying disputes associated with invasive species. In the ISI Web of Science database, we found 15,915 peer-reviewed publications on biological invasions, 124 of which included social dimensions of this phenomenon. Of these 124, 28 studies described specific contentious situations. Social approaches to biological invasions have emerged largely in the last decade and have focused on both environmental social sciences and resource management. Despite being distributed in a range of journals, these 124 articles were concentrated mostly in ecology and conservation-oriented outlets. We found that conflicts surrounding invasive species arose based largely on differences in value systems and to a lesser extent stakeholder and decision maker's risk perceptions. To confront or avoid such situations, we suggest integrating the plurality of environmental values into invasive species research and management via structured decision making techniques, which enhance effective risk communication that promotes trust and confidence between stakeholders and decision makers.
Keywords: biological invasions; cognitive hierarchy theory; non-native species; publication trends; risk analysis; science and society; social dimensions

Air distribution over a combustor liner - Jiang, Leiyong; Corber, P. Andrew (ASME Turbo Expo 2014: Turbine Technical Conference and Expo, 2014)
The splitting of the airflow that passes through the openings in the combustor liner is vital to its performance. Traditionally, numerical simulations of the gas turbine combustor have limited the computational domain to only the flow field inside the liner, while the airflow distribution over the liner is estimated based on semi-empirical correlations. In addition, the airflow rates are assumed to be the same through the identical open passages at each combustor axial cross-section. In the present study, the internal and external flow fields of a practical gas turbine combustor liner are directly coupled, so the air splitting is determined by comprehensive simulations. The predicted results for the air distribution are closely correlated to the dataset estimated from recently improved semi-empirical correlations for passage discharge-coefficients. The simulations also show that the effects of the combustion process on the air splitting can be neglected. Lastly, the results reveal that the airflow through identical passages at the same axial cross-section are not equal, and can vary by up to ±25% of the mean. In summary, the present study suggests that when performing computational models of gas turbine combustor flows, the simulations should couple the liner’s internal and external air splits whenever possible.

Climate change and microbial populations - Yergeau, Etienne (Antarctic Terrestrial Microbiology, 2014)
By 2100, the mean air temperature at the Earth’s surface is predicted to increase by 1.4 °C to 5.8 °C, with a disproportionate effect at high altitudes and latitudes. This chapter reviews the currently available information regarding the responses of key microbial parameters, including diversity, community composition, abundance and functions, to climate change in Antarctic soils. For microorganisms inhabiting Antarctic soils, some insight has been gained by comparing microbial communities across latitudinal gradients, or through short-term laboratory incubations and field studies. Rapid responses of mosses, nematodes, soil algae, cyanobacteria, fungi, and bacteria have been observed in some Antarctic soils. Despite these interesting findings, it is difficult to specifically predict the effects of warming on Antarctic soil microorganisms. One reason is the extreme heterogeneity of soil habitats in this region, as they vary from moist eutrophic ornithogenic soils to nutrient- and water-limited Dry Valley soils. Climate change might have rapid and direct effects on soil microbes that are not otherwise limited, but the release of other limitations (e.g., water, nutrients) could be more important in several environments.
Keywords: microbial ecology; bacteriology; microbial genetic; microbial genomics; geology

Predicting the origins of anti-blood group antibody specificity: a case study of the ABO A- and B-antigens - Makeneni, Spandana; Ji, Ye; Watson, David C.; Young, N. Martin; Woods, Robert J. (Frontiers in Immunology, 2014)
The ABO blood group system is the most important blood type system in human transfusion medicine. Here, we explore the specificity of antibody recognition toward ABO blood group antigens using computational modeling and biolayer interferometry. Automated docking and molecular dynamics simulations were used to explore the origin of the specificity of an anti-blood group A antibody variable fragment (Fv AC1001). The analysis predicts a number of Fv-antigen interactions that contribute to affinity, including a hydrogen bond between a HisL49 and the carbonyl moiety of the GalNAc in antigen A. This interaction was consistent with the dependence of affinity on pH, as measured experimentally; at lower pH there is an increase in binding affinity. Binding energy calculations provide unique insight into the origin of interaction energies at a per-residue level in both the scFv and the trisaccharide antigen. The calculations indicate that while the antibody can accommodate both blood group A and B antigens in its combining site, the A antigen is preferred by 4 kcal/mol, consistent with the lack of binding observed for the B antigen.
Keywords: Molecular docking; MD simulations; Blood group antigens; Antibody specificity; GLYCAM; AMBER

Light and behavior: a summary - Boyce, Peter R.; Veitch, Jennifer A. (Proceedings of IES Light + Behavior Symposium II, April 6-8, 2014, Cleveland, OH (LS-2-14), 2014)
In April 2014 the Illuminating Engineering Society held its second research symposium on the topic of “Light and Behavior”. Behavior is the output produced by people in response to physical and social stimulation. Lighting can certainly change the physical stimulation experienced by people so it is certainly one of the many factors that affect human behavior. Whereas the effects of lighting on visibility are well understood, how lighting changes human behavior is not; however, it is widely believed that different lighting conditions can influence work performance, individual comfort, safety, health and well-being and the overall quality of life. In an innovative format, speakers representing the design and research perspectives discussed their approaches to lighting for education, outdoor environment or healthcare applications. The designers presented examples of the issues they face in designing for the application and the researchers discussed the latest findings relevant to the application. This article is a summary of the symposium based on the authors' expertise, and includes research questions and new directions arising from the discussions over the two days of stimulating presentations and discussion.

Operability of lifeboats in pack ice: coxswains’ skill and design factors - Billard, Randy; Rahman, Md Samsur; Kennedy, Allison; Simões Ré, António; Veitch, Brian (Arctic Technology Conference: Proceedings; 10-12 Februray 2014, Houston Texas, 2014)
The paper describes an investigation into the operability of conventional lifeboats in pack ice conditions. The investigation was based on field trials of a small Totally Enclosed Motor Propelled Survival Craft (TEMPSC) lifeboat that was operated in a range of controlled pack ice conditions. The study focused on observing how operators with different levels of experience and backgrounds operated in ice, how their behaviors impacted their ability to maneuver through the ice field and the impact on the vessel and crew. Participants in the trials had different levels of experience operating in ice and in small crafts. The coxswains who participated in the investigation had a range of operational experience with vessels in ice, including operators who have worked aboard icebreaking vessels, but with limited experience operating in small vessels, and operators with experience operating small vessels, but with limited experience operating in ice. During the field trials, coxswains employed different tactics for advancing through ice. The outcomes of the study were used to analyze the impact of different driving techniques on the ability of the coxswain to successfully maneuver through ice and the impact of driving style on vessel integrity and crew comfort. The results of the study assess the tactics which can be employed by coxswains in different ice concentrations and the outcomes can be used to define learning objectives for training programs designed to prepare coxswains for emergency operations in ice covered waters.

Peak ice loads on a lifeboat in pack ice conditions - Kennedy, Allison; Simões Ré, António; Veitch, Brian (Arctic Technology Conference: Proceedings; 10-12 Februray 2014, Houston Texas, 2014)
Field testing of a modified Totally Enclosed Motor Propelled Survival Craft (TEMPSC) was conducted in March 2013 in managed level ice conditions. This testing was part of a multi-year trials program, conducted by the National Research Council (NRC), which aims to investigate design considerations for a conventional TEMPSC operating in ice. During the March 2013 testing campaign, the TEMPSC was equipped with a side impact panel and bow visor, both instrumented with load cells to measure local ice impact forces. The resulting local ice load measurements taken during this field trials campaign are presented and the operational performance is discussed. This was the first year during the trials campaign in which local loads on the stem were measured and recorded. The results of this set of field trials could be useful to support the implementation of new TEMPSC design considerations to allow for better performance in harsh, northern conditions. It could also provide operational insight to promote more effective and low stress navigation through ice conditions.

Land based multi-trophic aquaculture research at the wave energy research centre - Fiander, Leon; Graham, Mike; Murray, Harry; Boileau, Renee (2014 Oceans - St. John's, 2014)
The collapse of the Atlantic cod fishery in the 1990s devastated the economies of many coastal Newfoundland communities. While many have survived through a combination of a much reduced fishery, government funding, and off shore or out of province employment, none of these are sustainable longterm solutions. Sea-based aquaculture (“fish farming” in pens) has provided stable employment in some areas, but only where there are suitable sites with protected, deep inlets with significant tidal or river current flushing. These geographic characteristics are not usually compatible with prosecuting the inshore fishery. Sites that were close to the open fishing grounds with minimal near shore currents were prized by the small boat fishers, but wind and wave protection were a secondary concern. Thus there are many towns and villages that are significant distances from ideal sea-based aquaculture sites.
Keywords: aquaculture; wave energy integrated multi-trophic aquaculture; IMTA

Detailed ice ridge loading events on the Norströmsgrund lighthouse - Poirier, Louis; Sudom, Denise; Frederking, Robert (Proceedings of International Conference on Performance of Ships and Structures in Ice (ICETECH), 28-31 July, 2014, Banff, Alberta, 2014)
Three ridged ice loading events have been analyzed from the Norströmsgrund lighthouse, off the Swedish coast. Ice load data from 1999 and 2000 were collected as part of the LOLEIF project. The three events described in this paper occurred in March and April 2000. The ridges were relatively small, with maximum keels of less than 5 m depth and sails of less than 0.5 m height.
Keywords: Consolidated layer; ice load; keel; ridge

An overview of ice loads on structures - Frederking, Robert; Shkhinek, Karl; Barker, Anne (Proceedings of the 22nd IAHR International Symposium on Ice, 2014)
Ice of many forms grows annually on rivers, lakes and the sea, and as a consequence can interact with hydrotechnical or coastal structures, generating forces on them. These forces must be appropriately assessed and accounted for in the design of structures in water bodies affected by ice. Ice conditions such as thickness, strength, morphology and floe size influence ice forces and must be characterized and suitable extreme values of these features determined. The environmental driving forces of wind, current and temperature must also be understood. Information on ice conditions and environmental factors are combined to provide guidance on calculating the magnitude of ice forces that a structure might be expected to withstand over its lifetime. Various national and international standards and codes that provide guidance on ice forces have been introduced and a high level overview of determining ice loads provided. Areas that would benefit from further research include; investigation of compressive strength of ice for rates greater than 10-3 s-1, the relation between rate effects in laboratory tests and rate in ice loading of structures, and analytical work to implement ice constitutive relations into the nonuniform stress states of ice indentation.

Ice keel load distribution on cylindrical structures - Frederking, R.; Sand, B.; Sudom, D. (Proceedings of the 22nd IAHR International Symposium on Ice, 2014)
The ability to reliably predict ice forces generated by ridged ice features is very important for the design of offshore structures in many cold regions. Analytical models have been developed for predicting the loads on a structure due to interaction of an ice ridge keel or rubble, but few data exist for validating these models. In the present paper, the ice keel load distribution across the face of a vertical cylindrical structure is assessed. Ice load data collected in 2002 as part of the STRICE project at Norströmsgrund lighthouse were examined. Events for which the instrumented part of the lighthouse was responding only to ice keel loading were analysed to quantify horizontal ice keel pressures. The results have been compared with predictions of a numerical model. Numerical modeling is also used to predict the global ice forces and ice failure behavior for ridges of different size. From both full scale field data and numerical simulations of ridge interaction with the lighthouse, a trend of higher forces with increasing keel depths can be seen. In addition to generating larger global loads, larger ridges appear to create greater local loads around the waterline of the cylindrical structure. The load distribution across the lighthouse is not uniform. For some events, the forces on the load panels show a parabolic-type distribution while for others a different load distribution with two maxima is seen.

Re-analysis of load and pressure data acquired from ice impacts during the CCGS Louis St-Laurent 1994 Arctic voyage - Gagnon, Robert (Proceedings of the 22nd IAHR Internation Symposium on Ice, Singapore, August 2014, 2014)
Ice load and pressure data from the 1994 CCGS Louis St-Laurent trip through the Arctic were reanalyzed using a different method than was used for the original report. The impact events that were chosen for re-analysis spanned a variety of ship speeds, ice thicknesses and concentrations. For any given impact event all sub-panel segments (cells) of the strain-gauged hull panel for which a signal registered above the deemed noise level were considered to be subjected to ice load. Consequently all of the ice contact area, and associated ice load, was taken into account regardless of whether the ice contact consisted of a single area or multiple non-contiguous areas on the impacted panel. The data from a total of 51 randomly selected events covering a range of ice contact areas from 1.4 m2 to 16.8 m2 were initially analyzed to yield load and pressure distribution at the time of peak load for each event. Then further analysis was conducted to identify well-behaved events where the loaded areas were more contained on the panel and less concentrated at its edges. The effects of using this selection strategy are shown. For the data from the well-behaved events the pressure-area relationship was essentially flat with an average value 0.49 MPa over the stated range of contact area. Another set of 12 impact events were also analyzed, for which the full time-series of pressure on each of the 30 cells that comprise the panel were available from the original reduction of data. An analysis of load and contact area from these events demonstrated the effect of having oversized cells on ice impact panels, that leads to overestimates of ice contact area and underestimates of average pressure. The analysis suggested that the best estimates of actual ice contact area and average pressure, though still not fully accurate, are obtained when the contact area is the greatest, i.e. usually at peak load.

First lab tests of the blade runners concept for reducing ice induced vibration of structures - Gagnon, Robert (Proceedings of the 22nd IAHR Internation Symposium on Ice, Singapore, August 2014, 2014)
To test the Blade Runners concept for reducing ice induced vibration and loads on structures a simple configuration consisting of a single stationary blade on a rigid flat metal crushing plate was chosen for ice crushing tests in NRC-OCRE’s Large Cold Room facility. Five wedge-shaped columnar-grained freshwater ice samples were crushed against a thick plate with a low-profile blade on it and the results were compared with those from another five crushing experiments using a plate without a blade. The two crushing plates were made of aluminum and had identical characteristics other than that one of them had a blade on it. The blade had an isosceles right triangular section profile with a height of 1 mm and base of 2 mm. The blade spanned the length of the plate and was centered relative to the wedge-shaped ice samples and parallel with their long axes. Tests were conducted at -10oC and the nominal crushing plate displacement rate was 10 mm/s. High-speed imaging was used to observe the ice contact zone, by viewing through the ice samples, as it evolved and moved around somewhat during the tests. Load records from the tests using the bladeless crushing plate exhibited a high-amplitude sawtooth load pattern, resulting from fairly regular ice spalling events, that is typical of ice crushing in the brittle regime. This type of spalling behaviour, and associated sawtooth load pattern, is responsible for ice induced vibration of structures when ice sheets encroach on them. The average loads were roughly the same during either set of tests. However, for those tests where the plate with the blade on it was used it was observed that when the blade was in the hard zone region of the ice contact area the load pattern was dramatically affected. In those cases the blade effectively smoothed the sawtooth loading pattern by greatly increasing the spalling rate and reducing the spall size. Consequently the amplitudes of the load sawteeth were significantly reduced.

Solution to papal chemistry challenge - Meija, Juris (Analytical and Bioanalytical Chemistry, 2014)
The papal chemistry challenge sought to find a lesser-known connection between pontiffs and chemistry. The papal chemistry challenge has delved into the systematic nomenclature for naming newly discovered or not yet discovered elements. The element of the challenge is said to be Pope, as the symbol of the hypothetical chemical element with the atomic number 5859 is Pope.
Keywords: Atoms; Atomic numbers; Chemical elements

From physical chemistry to mass spectrometry to government lab manager in half a century - Boyd, Robert (Mass Spectrometry Reviews, 2014)
Robert Boyd pens down his journey and achievements from different stages of his career. In the initial days of his student life, he was attracted towards physical chemistry. He did his Ph.D work with Charles Horrex, and under his direction, managed to acquire some degree of skill in glass-blowing, Electronics, and machine shop, in order to construct his apparatus. His research project involved extension of an earlier student's work on a method of estimating carbon-iodine bond energies through study of pyrolysis of the organic iodides in excess HI. He had his first brush with mass spectrometry during his Ph.D. years. In 1964, he came to Ottawa to take up a job in the research laboratories of the British Electricity Board, then a publicly-owned utility located in Surrey in the south of England. He was involved in the open-cycle magnetohydrodynamics power generation project. His involvement with the journal Rapid Communications in Mass Spectrometry as an erstwhile Assistant Editor became much more intense in 1997 when he agreed to take over as Editor-in-Chief from John Beynon.
Keywords: Carbon; Chemical bonds; Glass manufacture; Machine shops; Magnetohydrodynamics; Mass spectrometry; Physical chemistry; Research laboratories; Spectrometry; Analytical applications; Carbon-iodine bonds; Different stages; Glass-blowing; Open cycles; Power generation projects; Rapid communication; Tandem mass spectrometry; Chemical analysis

Effect of freestream turbulence on airfoil limit-cycle oscillations at transitional reynolds numbers - Yuan, Weixing; Poirel, Dominique; Wang, Baoyuan; Benaissa, Azemi (Journal of Aircraft, 2014)
Numerical simulations are performed to study the effect of freestream turbulence on small-amplitude limit-cycle oscillations of an airfoil at transitionalReynolds numbers.Aone-degree-of-freedomaeroelastic modelwas coupledwith the National Research Council Canada in-house computational-fluid-dynamics code INSflow to perform unsteady Reynolds-averaged Navier-Stokes simulations for flows around a rigid NACA 0012 airfoil in free-to-rotate conditions. Without coupling a transitionmodel, unsteadyReynolds-averagedNavier-Stokes computations basedonthe commonly used shear-stress-transport turbulencemodel could not capture the limit-cycle oscillations. Thiswas expected because it had been previously shown that the limit-cycle oscillations were fed by negative aerodynamic damping due to laminar boundary-layer separation. A correlation-based transition model was then implemented in the code and applied to investigate the turbulence effects. The computed results confirmed qualitatively the experimental observations of the turbulence effects on the limit-cycle oscillations by varying the values of the turbulence intensity and length scale. It was observed that the limit-cycle oscillationsweremore sensitive to the turbulence intensity than to the latter. In general, the freestream turbulence suppressed the limit-cycle oscillations. The pitch amplitude became smaller when the freestream turbulence intensity was increased, which was qualitatively in good agreement with experimental results. The limit-cycle oscillations could not be sustainedwhen the input freestreamturbulence level reached around 1.25%.An examination of the unsteady flowfield revealed that the freestream turbulence affected the location of the separation points and suppressed the laminar-turbulent transition process.
Keywords: Airfoils; Boundary layer flow; Boundary layers; Computational fluid dynamics; Laminar boundary layer; Navier Stokes equations; Reynolds number; Shear stress; Turbulence; Boundary-layer separation; Computational Fluid Dynamics codes; Correlation-based transition models; Freestream turbulence intensity; Laminar turbulent transitions; Limit Cycle Oscillation (LCO); National Research Council; Unsteady reynolds-averaged navier-stokes; Atmospheric thermodynamics

Tissue composition, blood biochemistry and histology of digestive organs in Senegalese sole (Solea senegalensis) juveniles fed diets containing different plant protein ingredients - Rodiles, A.; Herrera, M.; Hachero-Cruzado, I.; Ruiz-Jarabo, I.; Mancera, J. M.; Cordero, M. L.; Lall, S. P.; Alarcón, F. J. (Aquaculture Nutrition, 2014)
The aim of this study was to determine the impact of diets with different plant protein ingredients on proximate composition, tissue metabolites and tissue fatty acid composition, as well as hepatic and intestinal histological modifications in Senegalese sole (Solea senegalensis). Fish (21.5 ± 2.8 g body weight) were fed six isonitrogenous and isoenergetic diets during 11 weeks. A control diet containing fish meal as the main protein source was compared with five experimental diets replacing 30% fish meal protein by different plant protein sources: soybean meal (SBM), soybean protein concentrate (SPC), soybean protein isolate (SPI), wheat gluten meal (WGM) or pea protein concentrate (PPC). The inclusion of different plant protein did not significantly affect growth and proximate composition of fish. The hepatosomatic index was not significantly different to the control group; however, utilization of WGM significantly increased hepatocyte size. Plasma protein values and muscle triglycerides were influenced by the inclusion of SBM and WGM in the diets respectively. Feeding fish on SBM, WGM and PPC diets significantly enhanced n-6 fatty acid levels in muscle, particularly linoleic acid. None of the plant protein ingredient used in the diets decreased arachidonic, eicosapentaenoic as well as docosahexaenoic acid values in liver and muscle. Overall, histological studies did not reveal the existence of any intestinal alterations induced by the inclusion of different plant proteins. Despite moderate changes produced by SBM, SPC and WGM, inclusion of dietary plant protein ingredients has no major impact on growth, tissue and blood biochemistry, fatty acid profile and gut integrity of Senegalese sole juveniles.

High and low cycle fatigue behavior of linear friction welded Ti-6Al-4V - Stinville, J. C.; Bridier, F.; Ponsen, D.; Wanjara, P.; Bocher, P. (International Journal of Fatigue, 2014)
Linear friction welded Ti-6Al-4V was investigated in fatigue at various stress amplitudes ranging from the high cycle fatigue (HCF) to the low cycle fatigue (LCF) regime. The base material was composed of hot-rolled Ti-6Al-4V plate that presented a strong crystallographic texture. The welds were characterized in terms of microstructure using electron backscatter diffraction and hardness measurements. The microstructural gradients across the weld zone and thermomechanically affected zone of the linear friction welds are discussed in terms of the crystallographic texture, grain shape and hardness levels, relative to the parent material. The location of crack nucleation under fatigue loading was analyzed relative to the local microstructural features and hardness gradients. Though crack nucleation was not observed within the weld or thermomechanically affected zones, its occurrence within the base material in LCF appears to be affected by the welding process. In particular, by performing high resolution digital image correlation during LCF, the crack nucleation site was related to the local accumulation of plastic deformation in the vicinity of the linear friction weld.
Keywords: Digital image correlations; Electron back scatter diffraction; Fatigue properties; High and low cycle fatigue; Linear friction; Ti alloys; Ti-6 Al-4 V; Friction welding

Symbols of the elements, part II - Meija, Juris (Chemistry International, 2014)
Typographical symbols of chemical elements were established in the early 19th century and they soon spread throughout the textbooks of chemistry. This spread, however, was not an exemplary adoption of international standards. Rather, a garden variety of individual notations soon emerged. This is a brief story of their eradication.
Keywords: element

Symbols of the elements, part III (concluded) - Meija, Juris (Chemistry International, 2014)
During the 20th century the IUPAC symbols for all known chemical elements gradually became the international standard. With the house all in order, the proposed symbols for all newly discovered elements were now scrutinized more than ever, and the nomenclature was set for elements which have not yet been discovered. This is the story of the 20th century.
Keywords: element

Updated temperature, salinity and strength distributions for old ice - Johnston, M.; Frederking, R. (IceTech '11, 2014)
This paper presents updated distributions of the temperatures, salinities and borehole strengths of old ice, as a function of time of year. Thousands of measurements are compiled from old ice floes across the Arctic. Probability of exceedance curves are used to show the more ‘extreme’ values that can occur at various depths in the ice, whereas properties over the full ice thickness are obtained from (i) the means of populations and (ii) by depth-averaging measurements from the same borehole.
Keywords: old ice; ice temperature; salinity; borehole strength; flexural strength; probability of exceedance

Role of skeletal muscle in mandible development - Rot, Irena; Mardesic-Brakus, Snjezana; Costain, Willard J.; Saraga-Babic, Mirna; Kablar, Boris (Histology and Histopathology, 2014)
As a continuation of the previous study on palate development (Rot and Kablar, 2013), here we explore the relationship between the secondary cartilage mandibular condyles (parts of the temporomandibular joint) and the contributions (mechanical and secretory) from the adjacent skeletal musculature. Previous analysis of Myf5-/-:MyoD-/- mouse fetuses lacking skeletal muscle demonstrated the importance of muscle contraction and static loading in mouse skeletogenesis. Among abnormal skeletal features, micrognathia (mandibular hypoplasia) was detected: small, bent and posteriorly displaced mandible. As an example of Waddingtonian epigenetics, we suggest that muscle, in addition to acting via mechanochemical signal transduction pathways, networks and promoters, also exerts secretory stimuli on skeleton. Our goal is to identify candidate molecules at that muscle-mandible interface. By employing Systematic Subtractive Microarray Analysis approach, we compared gene expression between mandibles of amyogenic and wild type mouse fetuses and we identified up- and down-regulated genes. This step was followed by a bioinformatics approach and consultation of web-accessible mouse databases. We searched for individual tissue-specific gene expression and distribution, and for the functional effects of mutations in a particular gene. The database search tools allowed us to generate a set of candidate genes with involvement in mandibular development: Cacna1s, Ckm, Des, Mir300, Myog and Tnnc1. We also performed mouse-to-human translational experiments and found analogies. In the light of our findings we discuss various players in mandibular morphogenesis and make an argument for the need to consider mandibular development as a consequence of reciprocal epigenetic interactions of both skeletal and non-skeletal compartments.
Keywords: Skeletal muscle; Mandible; Mouse; Development; Epigenetics

V363 And: a detached eclipsing binary - Nelson, Robert H. (Information Bulletin on Variable Stars, 2014)

Performance in fire of fibre reinforced polymer strengthened concrete beams and columns: recent research and implications for design - Green, Mark; Hollingshead, Kevin; Bénichou, Noureddine (Journal of Structural Fire Engineering, 2014)
This paper considers the fire performance of concrete beams and columns that have been strengthened with fibre reinforced polymers (FRPs). Results from four recent full-scale tests are presented. A newly developed type of insulation was employed and the thickness of the insulation (15 to 20 mm) was approximately half that provided in earlier tests. All of the members survived four hours of the fire exposure. A conceptual model for design to determine when insulation is required is also presented. Further research needed to fully develop the conceptual model to a more practical design tool is outlined.
Keywords: Fire; Fibre Reinforced Polymers; Concrete; Strengthening; Repair; Rehabilitation

Semi-classical methods in non-sequential double ionization - Johnson, Allan S.; Staudte, André; Villeneuve, D. M. (Chinese journal of physics, 2014)
Non-sequential double ionization of an atom in an intense lasereld is a prototypical problem in multi-body strong eld interactions. To examine non-sequential double ionization, an often used approach is the semi-classical method, by which initial conditions are set according to quantum expressions and the ensuing dynamics modelled classically. Here we present a comparative study of quantum and semi-classical methods in the single active electron approximation. We show that semi-classical methods over-estimate the kinetic energy of rescattered electrons by up to 150%. We further show that the return time of the recolliding electrons deviates between quantum and semi-classical methods at low intensities, and that the deviation is attributable to the choice of the initial tunnelling position.

Intense few-cycle infrared laser pulses at the advanced laser light source - Schmidt, B. E.; Shiner, A. D.; Giguère, M.; Trallero-Herrero, C.; Lassonde, P.; Thiré, N.; Villeneuve, D. M.; Corkum, P. B.; Légaré, F. (Chinese Journal of Physics, 2014)
To push the generation of isolated attosecond pulses towards shorter XUV wavelengths (0.3 to 1 keV), intense few-cycle driving pulses are required whose center frequency is significantly red shifted compared to established Ti-Sa technology. A simple route for generating these pulses is demonstrated using an optical parametric amplifier (OPA). Its infrared (IR) multi-cycle laser pulses with millijoule of energy are spectrally broadened by nonlinear propagation in a hollow-core fiber (HCF) filled with Argon. For the OPA Signal wavelength (λ = 1.4 micron), chirped mirrors were used for dispersion compensation with a resulting pulse duration of 13.1 fs. For the OPA Idler wavelength at 1.8 micron, a new compression scheme has been developed with which 11.2 fs laser pulses have been characterized (1 cycle= 6 fs). Here, pulse compression is achieved through the combined effects of self-steepening during nonlinear propagation in the HCF followed by anomalous dispersion during linear propagation in fused silica.

Control of femtosecond laser ablation of thin films from a dielectric surface by nonlinear interaction with the substrate - Mercadier, Laurent; Rayner, David M.; Corkum, Paul B. (Physical Review Applied, 2014)
Controlling the interaction of an ultrafast laser pulse with a thin film remains a difficult task, especially when aiming to confine material modifications to subwavelength scales. We introduce a method to achieve reproducible submicron ablation of thin films from a dielectric surface, in a back-irradiation geometry. First, the pulse of 45-fs duration and 800-nm central wavelength nonlinearly interacts with the dielectric and undergoes strong but reproducible modifications of its intensity profile. Then, the pulse ablates a thin polymer film [four bilayers of poly(allylamine hydrochloride) and poly(sodium 4-styrene-sulfonate), 8 nm thick] from the back surface. We measure the hole with atomic force microscopy and study the influence of laser energy and focal plane position. The radius of the resulting hole is determined by a threshold intensity for ablation. Therefore, we also demonstrate how measuring the radius as a function of focal plane position provides a new approach to profiling a tightly focused laser beam under nonlinear propagation conditions. We compare the beam profile with that predicted by a widely used propagation model and show that the latter can semiquantitatively be applied to estimate the size of achievable holes.

Photon momentum sharing between an electron and an ion in photoionization: from one-photon (photoelectric effect) to multiphoton absorption - Chelkowski, Szczepan; Bandrauk, André D.; Corkum, Paul B. (Physical Review Letters, 2014)
We investigate photon-momentum sharing between an electron and an ion following different photoionization regimes. We find very different partitioning of the photon momentum in one-photon ionization (the photoelectric effect) as compared to multiphoton processes. In the photoelectric effect, the electron acquires a momentum that is much greater than the single photon momentum ℏω/c [up to (8/5) ℏω/c] whereas in the strong-field ionization regime, the photoelectron only acquires the momentum corresponding to the photons absorbed above the field-free ionization threshold plus a momentum corresponding to a fraction (3/10) of the ionization potential Ip. In both cases, due to the smallness of the electron-ion mass ratio, the ion takes nearly the entire momentum of all absorbed N photons (via the electron-ion center of mass). Additionally, the ion takes, as a recoil, the photoelectron momentum resulting from mutual electron-ion interaction in the electromagnetic field. Consequently, the momentum partitioning of the photofragments is very different in both regimes. This suggests that there is a rich, unexplored physics to be studied between these two limits which can be generated with current ultrafast laser technology.

Applications of ultrafast wavefront rotation in highly nonlinear optics - Quéré, F.; Vincenti, H.; Borot, A.; Monchocé, S.; Hammond, T.J.; Kim, K.T.; Wheeler, J.A.; Zhang, C.; Ruchon, T.; Auguste, T.; Hergott, J.F.; Villeneuve, D.M.; et al. (Journal of Physics B: Atomic, Molecular and Optical Physics, 2014)
This paper provides an overview of ultrafast wavefront rotation of femtosecond laser pulses and its various applications in highly nonlinear optics, focusing on processes that lead to the generation of high-order harmonics and attosecond pulses. In this context, wavefront rotation can be exploited in different ways, to obtain new light sources for time-resolved studies, called 'attosecond lighthouses', to perform time-resolved measurements of nonlinear optical processes, using 'photonic streaking', or to track changes in the carrier-envelope relative phase of femtosecond laser pulses. The basic principles are explained qualitatively from different points of view, the experimental evidence obtained so far is summarized, and the perspectives opened by these effects are discussed. © 2014 IOP Publishing Ltd.
Keywords: Harmonic generation; Light sources; Nonlinear optics; Ultrafast lasers; Wavefronts; Attosecond pulse; Experimental evidence; High harmonic generation; Nonlinear optical process; Spatio-temporal; Time resolved measurement; Time resolved studies; Ultrafast measurements; Ultrashort pulses

Alignment dependent enhancement of the photoelectron cutoff for multiphoton ionization of molecules - Smeenk, C.T.L.; Arissian, L.; Sokolov, A.V.; Spanner, M.; Lee, K.F.; Staudte, A.; Villeneuve, D.M.; Corkum, P.B. (Physical Review Letters, 2014)
The multiphoton ionization rate of molecules depends on the alignment of the molecular axis with respect to the ionizing laser polarization. By studying molecular frame photoelectron angular distributions from N2, O2, and benzene, we illustrate how the angle-dependent ionization rate affects the photoelectron cutoff energy. We find alignment can enhance the high energy cutoff of the photoelectron spectrum when probing along a nodal plane or when ionization is otherwise suppressed. This is supported by calculations using a tunneling model with a single ion state. © 2014 American Physical Society.
Keywords: Alignment; Molecules; Photoelectrons; Photons; Angle-dependent; Cutoff energies; Ionization rates; Laser polarization; Multiphoton ionization; Photoelectron angular distributions; Photoelectron spectrum; Tunneling models; Photoionization

Manipulating quantum paths for novel attosecond measurement methods - Kim, K.T.; Villeneuve, D.M.; Corkum, P.B. (Nature Photonics, 2014)
Sources of attosecond-duration light pulses provide the fastest time resolutions available today for observing ultrafast phenomena in atoms, molecules and condensed matter. The measurement of such pulse durations is challenging because the spectrum lies in the vacuum ultraviolet or soft X-ray range. Two classes of pulse duration measurements now exist; they are classified according to whether the measurement is performed in the generating medium or in a second medium. The first measurement class is called 'in situ' and depends on gently perturbing the electron responsible for attosecond pulse formation. The second measurement class, which we refer to as 'ex situ', takes place in a second medium in which photoelectrons are produced by the attosecond pulses; a synchronized laser field perturbs the photoelectron spectrum. This Review compares and contrasts these two approaches for measuring attosecond pulses. © 2014 Macmillan Publishers Limited.
Keywords: Attosecond measurement; Attosecond pulse; Condensed matter; Photoelectron spectrum; Soft x-ray range; Synchronized laser; Time resolution; Vacuum ultraviolets; Photonics

Subcycle control of electron-electron correlation in double ionization - Zhang, L.; Xie, X.; Roither, S.; Zhou, Y.; Lu, P.; Kartashov, D.; Schöffler, M.; Shafir, D.; Corkum, P.B.; Baltuška, A.; Staudte, A.; Kitzler, M. (Physical Review Letters, 2014)
Double ionization of neon with orthogonally polarized two-color (OTC) laser fields is investigated using coincidence momentum imaging. We show that the two-electron emission dynamics in nonsequential double ionization can be controlled by tuning the subcycle shape of the electric field of the OTC pulses. We demonstrate experimentally switching from correlated to anticorrelated two-electron emission, and control over the directionality of the two-electron emission. Simulations based on a semiclassical trajectory model qualitatively explain the experimental results by a subcycle dependence of the electron recollision time on the OTC field shape. © 2014 American Physical Society.
Keywords: Computer simulation; Electric fields; Ionization of gases; Coincidence momentum imaging; Double ionization; Electron recollisions; Electron-electron correlation; Emission dynamics; Laser fields; Nonsequential double ionizations; Trajectory modeling; Electron emission

Creating high-harmonic beams with controlled orbital angular momentum - Gariepy, G.; Leach, J.; Kim, K.T.; Hammond, T.J.; Frumker, E.; Boyd, R.W.; Corkum, P.B. (Physical Review Letters, 2014)
A beam with an angular-dependant phase Φ=φ about the beam axis carries an orbital angular momentum of per photon. Such beams are exploited to provide superresolution in microscopy. Creating extreme ultraviolet or soft-x-ray beams with controllable orbital angular momentum is a critical step towards extending superresolution to much higher spatial resolution. We show that orbital angular momentum is conserved during high-harmonic generation. Experimentally, we use a fundamental beam with | =1 and interferometrically determine that the harmonics each have orbital angular momentum equal to their harmonic number. Theoretically, we show how any small value of orbital angular momentum can be coupled to any harmonic in a controlled manner. Our results open a route to microscopy on the molecular, or even submolecular, scale. © 2014 American Physical Society.
Keywords: Orbital angular momentum

Strong field processes inside gallium arsenide - Golin, S.M.; Kirkwood, S.E.; Klug, D.D.; Villeneuve, D.M.; Rayner, D.M.; Herrero, C.A.T.; Corkum, P.B. (Journal of Physics B: Atomic, Molecular and Optical Physics, 2014)
We demonstrated experimentally that the multiphoton ionization rate in gallium arsenide depends on the alignment of the laser polarization with respect to the crystal axis. We observed modulation in the ionization rate of a linearly-polarized 1900 nm laser beam directly by measuring its transmission while rotating the crystal, without Fourier analysis. We propose that the modulation in the ionization rate arises from periodic variation in the reduced carrier mass, as predicted by Keldysh theory. We show direct comparison of the experimental transmission modulation depth with Keldyshs non-resonant ionization theory for solids. This opens up a novel method for non-invasive crystallography of semiconductor materials. © 2014 IOP Publishing Ltd.
Keywords: Semiconductor materials; GaAs; Strong field; Ultra-fast; Ionization

Laser-sub-cycle two-dimensional electron-momentum mapping using orthogonal two-color fields - Zhang, L.; Xie, X.; Roither, S.; Kartashov, D.; Wang, Y.; Wang, C.; Schöffler, M.; Shafir, D.; Corkum, P.B.; Baltuška, A.; Ivanov, I.; Kheifets, A.; et al. (Physical Review A - Atomic, Molecular, and Optical Physics, 2014)
We study laser-sub-cycle control over electron trajectories concomitantly in space and time using orthogonally polarized two-color laser fields. We compare experimental photoelectron spectra of neon recorded by coincidence momentum imaging with photoelectron spectra obtained by semiclassical and numerical solutions of the time-dependent Schrödinger equation. We find that a resolution of a quarter optical cycle in the photoelectron trajectories can be achieved. It is shown that depending on their sub-cycle birth time the trajectories of photoelectrons are affected differently by the ion's Coulomb field. © 2014 American Physical Society.
Keywords: Photoelectrons; Photons; Trajectories; Coincidence momentum imaging; Dinger equation; Electron momentum; Electron trajectories; Numerical solution; Optical cycles; Photoelectron spectrum; Two-color laser fields; Photoelectron spectroscopy

Control of atomic single and double ionization dynamics using orthogonally polarized two-color laser pulses - Zhang, L.; Xie, X.; Roither, S.; Kartashov, D.; Schöffler, M.; Shafir, D.; Corkum, P.B.; Baltuka, A.; Staudte, A.; Kitzler, M. (Journal of Physics: Conference Series, 2014)
Single- and double-ionization of neon with orthogonally polarized two-color (OTC) laser fields is investigated using the COLTRIMS method. We study the influence of the long range Coulomb potential of the parent ion on the final momentum distribution of electrons emitted during single ionization. Furthermore, we investigate nonsequential double ionization in OTC fields and demonstrate that the electron-electron correlation is highly sensitive to the sub-cycle field shape of the OTC pulses, in agreement with recent theoretical predictions.
Keywords: Electric fields; Impact ionization; Ionization of gases; Atoms; Electric fields; Electron correlations; Impact ionization; Ionization; Ionization of gases; Coulomb potential; Double-ionization dynamics; Electron-electron correlation; Laser fields; Momentum distributions; Nonsequential double ionizations; Single ionization; Two-color laser pulse; Double ionization; Atoms; Ionization potential

Theoretical analysis of high-harmonic generation in solids - Vampa, G.; McDonald, C.R.; Orlando, G.; Klug, D.D.; Corkum, P.B.; Brabec, T. (Physical Review Letters, 2014)
We investigate theoretically high-harmonic generation (HHG) in bulk crystals exposed to intense midinfrared lasers with photon energies smaller than the band gap. The two main mechanisms, interband and intraband HHG, are explored. Our analysis indicates that the interband current neglected so far is the dominant mechanism for HHG. Saddle point analysis in the Keldysh limit yields an intuitive picture of interband HHG in solids similar to atomic HHG. Interband and intraband HHG exhibit a fundamentally different wavelength dependence. This signature can be used to experimentally distinguish between the two mechanisms in order to verify their importance. © 2014 American Physical Society.
Keywords: Atomic physics; Physics; Bulk crystals; Dominant mechanism; Exposed to; High harmonic generation; Midinfrared lasers; Photon energy; Saddle point; Wavelength dependence; Harmonic generation

Study of processing conditions on the forming of ribbed features using randomly-oriented strands thermoplastic composites - LeBlanc, Dominic; Landry, Benoit; Levy, Arthur; Roy, Steven; Yousefpour, Ali; Quinlan, Erin; Hubert, Pascal (AHS 70th Annual Forum, 2014)
Compression moulding of randomly-oriented strands composites offer the possibility to manufacture complex parts with fast processing cycle. In this paper, effects of pressure, strand size, temperature and material placement in the mould cavity on the quality of a T-shape part were studied experimentally. Low pressure results showed both strand size and temperature effects on the filling of a 25 mm rib deep cavity. Critical filling pressures for three strand sizes were obtained. A pressure of 10 bar was enough to fully consolidate parts with smaller strand (3.17 mm × 6.35 mm) at 400 °C. Parts processed at filling pressure showed a void content no greater than 1.2 %. Increasing pressure to 70 bar resulted in decreased void content between 0.44 % and 0.03 %. The lowest void content was obtained for parts processed at lower temperature. Short-beam shear (ASTM D2344) showed similar strength for ribs processed at filling pressure and high pressure (70 bar). This same trend was observed for component testing of the T-shape. At the component level, initial strand placement greatly affected mechanical performance as merging flow fronts caused a knit line and a reduction of at most 40 % in strength. The main findings show that processing a complex feature at filling pressure Pfill was sufficient to reach nominal mechanical properties. This suggested that moderate porosity was not detrimental to the mechanical performance for the given tests.
Keywords: Mechanical properties; Component testing; Filling pressures; Lower temperatures; McGill University; Mechanical performance; Montreal , Canada; Processing condition; Thermoplastic composite; Helicopters

Assessing the discourse factors that influence the quality of machine translation - Li, Junyi Jessy; Carpuat, Marine; Nenkova, Ani (52nd Annual Meeting of the Association for Computational Linguistics, ACL 2014, 2014)
We present a study of aspects of discourse structure - specifically discourse devices used to organize information in a sentence- that significantly impact the quality of machine translation. Our analysis is based on manual evaluations of translations of news from Chinese and Arabic to English. We find that there is a particularly strong mismatch in the notion of what constitutes a sentence in Chinese and English, which occurs often and is associated with significant degradation in translation quality. Also related to lower translation quality is the need to employ multiple explicit discourse connectives (because, but, etc.), as well as the presence of ambiguous discourse connectives in the English translation. Furthermore, the mismatches between discourse expressions across languages significantly impact translation quality.
Keywords: Computer aided language translation; Discourse structure; Machine translations; Translation quality; Computational linguistics

Expanded fatigue damage and load time signal estimation for dynamic helicopter components using computational intelligence techniques - Cheung, Catherine; Rocha, Bruno; Valdés, Julio J.; Kotwicz-Herniczek, Mark; Stefani, Anton (Forum 70: American Helicopter Association, 2014)
Load signal prediction and fatigue damage accumulation estimation results are presented for a wide range of flight conditions from the S-70A-9 Black Hawk flight loads survey performed in 2000. Results from twelve manoeuvres were included in this study, ranging from very specific steady state and transient manoeuvres to more general manoeuvres with varying speed, direction, and aircraft orientations. The load time signal predictions were obtained following a simplified methodology and then the resulting fatigue damage accumulation was calculated for each manoeuvre. These estimates were generated using developed computational models, consisting of a variety of computational intelligence techniques and statistical methods, coupled with online Rainflow counting, the material specific S-N curve, and Palmgren-Miner's linear damage rule
Keywords: artificial intelligence; military helicopters; signal filtering and prediction; computational intelligence techniques; computational model; estimation results; fatigue damage accumulation; flight conditions; linear damage rule; rainflow counting; steady state and transients; fatigue damage

A model of ice friction for skeleton sled runners - Lozowski, Edward; Szilder, Krzysztof; Maw, Sean; Morris, Alexis (24th International Ocean and Polar Engineering Conference, ISOPE 2014, 2014)
A numerical model of ice friction for the runners of a skeleton sled has been devised. The skeleton runner consists of a standard stainless steel rod of approximately 16 mm diameter. Two grooves are machined into the trailing half of the runner. The distance between the grooves is approximately 1mm, giving rise to a spine or blade at the centre of the runner. The skeleton sled has no apparent mechanism for steering. Hence, steering is accomplished by the athlete, using either lateral air drag forces (tilting the helmet), dragging a toe, or by attempting to make the spine of the runner “dig into” the ice more on one side than the other. Until now, the physics of the latter steering mechanism has been poorly understood. It has been assumed that when the spine “digs into” the ice, the ice friction increases. Our numerical model calculates the details of the contact footprint of the runner on the ice. It also considers frictional heating, heat conduction into the ice and lateral squeeze flow in order to calculate the ice friction coefficient, assuming fully lubricated friction conditions. The model suggests that skeleton sliding can occur in two regimes. The first is one where the sides of the spine do not contact the ice. The second occurs when the spine “digs into” the ice and the sides of the spine contact the ice. By exploring the second regime, we have shown that, as the contact area between the sides of the spine and the ice increases, the ploughing force increases, in accordance with the traditional explanation of steering. However, the shear stress force in the lubricating layer also increases, resulting in a significantly higher ice friction coefficient for the runner with the longer spine contact. This result provides scientific evidence to support the athlete’s experience, that by engaging more of the spine by torqueing the frame of the sled, it is possible to steer the sled, using the differential ice friction on the left and right runners.
Keywords: Friction; Ice; Model; Physics; Skeleton sled; Theory

Compression moulding of complex parts using randomly-oriented strands thermoplastic composites - LeBlanc, Dominic; Landry, Benoit; Levy, Arthur; Hubert, Pascal; Roy, Steven; Yousefpour, Ali (SAMPLE Seattle 2014, 2014)
Randomly-oriented strands composites offer the possibility to mould complex parts with fast processing cycle. In this paper, effects of pressure and strand size on the quality of a T-shape part were studied experimentally. Low pressure results showed strand size effects on the filling of a 25 mm rib cavity. Filling pressures for three strand sizes were obtained. 10 bar of pressure was enough to fully consolidate parts with smaller strands (3.17 mm × 6.35 mm). Analyzing parts processed at minimal filling pressure showed a void content in the rib feature no greater than 1.2 %. Processing at higher pressure reduced void content between 0.22 % and 0.44 %. Mechanical testing (ASTM D2344) showed similar strength for ribs processed at filling pressure and high pressure. This same trend was obtained for component testing of the T-shape. The main findings show that processing a complex feature at filling pressure Pfill was sufficient to reach nominal mechanical properties. This suggested that porosity was not detrimental to the mechanical performance for the given tests.
Keywords: Complex parts; Component testing; Fast Processing; Filling pressures; High pressure; Mechanical performance; Thermoplastic composite; Void contents

Conduction heating for adhesive bonding of rotorcraft primary structure - Hind, S.; Djokic, D.; Verdino, J.; Yousefpour, A. (70th American Helicopter Society International Annual Forum, 2014)
A final stage in the manufacturing of a rotorcraft structural article is presented. A single-part composite skin is stiffened with a series of pre-cured composite frames. Legacy designs feature either mechanically fastened metallic skin and frames, or longitudinally split composite skin bonded and fastened to composite frames. In the new design, all frames are simultaneously bonded using a high-performance, thermally-activated film adhesive. No fasteners are used. This approach improved the load transfer, damage tolerance, and part count. The success of this complex bonding operation is highly dependent on the control of the process parameters, mainly the bondline temperature. Required temperature uniformity across all bondlines was achieved by independently controlled conductive Heat Transfer Tiles (HTT's) dedicated to each frame. The National Research Council's HTT technology delivers nonuniform heat flux based on variable thermal boundary conditions which results in improved temperature uniformity compared to traditional heater blankets. Custom HTTs, control system and fixturing were evaluated and used to manufacture seven test articles. The success of the exercise was confirmed by process data, non-destructive, destructive, and full-scale testing.
Keywords: Flight control systems; Heat flux; Heat transfer; Helicopter rotors; Helicopters; Manufacture; Structural frames; Conductive heat transfer; Full-scale testing; National Research Council; Non-uniform heat fluxes; Primary structures; Process parameters; Temperature uniformity; Thermal boundary conditions; Rotors

Natural attenuation potential for oil in ice in the Canadian Arctic marine environment - Greer, Charles W.; Wyglinski, Joanne; Michel, Christine; Fortin, Nathalie; Sanschagrin, Sylvie; Niemi, Andrea; Whyte, Lyle G.; King, Thomas L.; Lee, Kenneth; Yergeau, Etienne (37th AMOP Technical Seminar on Environmental Contamination and Response, 2014)
The exploration and exploitation of oil and gas resources in Canada’s Arctic carries with it certain risks that include the potential for oil spills and their effects on this fragile, yet extreme ecosystem. To develop an effective response strategy for an oil spill in an Arctic environment that would consist of a mixture of seawater and sea ice, a survey was conducted in the area of Cornwallis Island to develop baseline data on the natural microbial community structures and to determine whether these indigenous species possess the capacity to degrade petroleum hydrocarbons. Metagenomics and high throughput sequencing are relatively new approaches using modern genomics techniques to directly study communities of microorganisms in their natural environments, avoiding the need for traditional isolation and culturing. This provides more relevant ecological data, since the results directly relate to the population structure of the microorganisms that are present as well as the functional potential of the community, such as, for example, its inherent capacity to degrade petroleum hydrocarbons. Based on high-throughput sequencing of total community 16S rRNA gene amplicons and metagenomic sequencing, the indigenous bacterial populations in sea water were significantly different from those associated with the underside of the sea ice. Both sea water and sea ice were dominated by Bacteroidetes (Flavobacteria) but seawater was also abundant in Proteobacteria, primarily Alpha- and Gammaproteobacteria. The bottom of the sea ice demonstrated selective enrichment for Gammaproteobacteria, which contains numerous genera of obligate hydrocarbon degrading bacteria, such as Alkanivorax and Oleispira. There were both spatial and physicochemical influences on the microbial population structures, indicating that variations in the local environment can shape the structure of the microbial community, findings that are supported by other studies on polar microbial communities. These results demonstrate that seawater and sea ice in the Canadian Arctic possess natural microbial communities with the inherent ability to degrade petroleum hydrocarbons.
Keywords: Bacteria; Ecosystems; Energy resources; Hydrocarbons; Oil shale; Oil spills; Petroleum chemistry; Petroleum deposits; Population statistics; RNA; Sea ice; Seawater effects; Throughput; Exploration and exploitation; High-throughput sequencing; Hydrocarbon degrading bacteria; Microbial community structures; Microbial populations; Petroleum hydrocarbons; Physicochemical influences; Population structures; Natural attenuation

Development of thermoplastic composite cones for helicopter tail boom application - Hoa, Suong V.; Shadmehri, Farjad; Cai, Xiao; Simpson, Jeff; Hubert, Pascal; Quinlan, Erin; Brulotte, Xavier; D’Arienzo, Vincent; Beaulieu, Peter; Dion, Michel; Hojjati, Mehdi; Chen, Jihua (AHS Forum 70, 2014)
Thermoplastic composites offer many attractive characteristics such as no shelf life, high fracture toughness, high temperature resistance, recyclability etc. The short coming of thermoplastic composites is their high viscosity, even at processing temperature. Due to the high viscosity, techniques for the manufacturing of thermoplastic composite have been limited to molding processes such as compression molding, high temperature stamping, where high temperature, high pressure and long duration are used. The advent of automated fiber placement machine brings forward possibilities to manufacture of large thermoplastic composite components. This is due to the fact that heating and compaction is done on the go directly on the surface of the substrate, and the flexibility of the feeding head to conform to the shape of the mold. It is in the spirit of exploration for new manufacturing possibilities that Bell Helicopter has supported an inter industry- university project for the development of thermoplastic composite cones aimed at helicopter tail boom applications. The cone represents a segment of the helicopter tail boom. It is made using carbon/PEEK material and automated fiber placement. The work consists of the Determination of the lay-up sequence to address the loads, the Development of the manufacturing processes, the Measurement of temperature variation during the making of a ring, the Checking of the quality of the cone, Development of tube bending test set up, Development of theoretical calculations to determine the buckling load of the cone subjected to bending, Testing the cone under bending load, and Comparing the experimental buckling with calculated buckling load.

Calcium-sensing receptors of human astrocyte-neuron teams : amyloid-β-driven mediators and therapeutic targets of Alzheimer’s disease - Pra, I.; Chiarini, A.; Pacchiana, R.; Gardenal, E.; Chakravarthy, B.; Whitfield, J.; Armato, U. (Current Neuropharmacology, 2014)
It is generally assumed that the neuropathology of sporadic (late-onset or nonfamilial) Alzheimer’s disease (AD) is driven by the overproduction and spreading of first Amyloid-βx-42 (Aβ42) and later hyperphosphorylated (hp)-Tau oligomeric “infectious seeds”. Hitherto, only neurons were held to make and spread both oligomer types; astrocytes would just remove debris. However, we have recently shown that exogenous fibrillar or soluble Aβ peptides specifically bind and activate the Ca2+-sensing receptors (CaSRs) of untransformed human cortical adult astrocytes and postnatal neurons cultured in vitro driving them to produce, accrue, and secrete surplus endogenous Aβ42. While the Aβ-exposed neurons start dying, astrocytes survive and keep oversecreting Aβ42, nitric oxide (NO), and vascular endothelial growth factor (VEGF)-A. Thus astrocytes help neurons’ demise. Moreover, we have found that a highly selective allosteric CaSR agonist (“calcimimetic”), NPS R-568, mimics the just mentioned neurotoxic actions triggered by Aβ●CaSR signaling. Contrariwise, and most important, NPS 2143, a highly selective allosteric CaSR antagonist (“calcilytic”), fully suppresses all the Aβ●CaSR signaling-driven noxious actions. Altogether our findings suggest that the progression of AD neuropathology is promoted by unceasingly repeating cycles of accruing exogenous Aβ42 oligomers interacting with the CaSRs of swelling numbers of astrocyte-neuron teams thereby recruiting them to overrelease additional Aβ42 oligomers, VEGF-A, and NO. Calcilytics would beneficially break such Aβ/CaSR-driven vicious cycles and hence halt or at least slow the otherwise unstoppable spreading of AD neuropathology
Keywords: Alzheimer’s disease; amyloid-beta oligomers; astrocyte-neuron teams; calcium-sensing receptor; calcilytics; calcimimetics.

Searching for patterns in imbalanced data : methods and alternatives with case studies in life sciences - Famili, A. Fazel (2014)
The prime motivation for pattern discovery and machine learning research has been the collection and warehousing of large amounts of data, in many domains such as life sciences and industrial processes. Examples of unique problems arisen are situations where the data is imbalanced. The class imbalance problem corresponds to situations where majority of cases belong to one class and a small minority belongs to the other, which in many cases is equally or even more important. To deal with this problem a number of approaches have been studied in the past. In this talk we provide an overview of some existing methods and present novel applications that are based on identifying the inherent characteristics of one class vs the other. We present the results of a number of studies focusing on real data from life science applications.
Keywords: Knowledge discovery; imbalanced data; gene expression data

Addressing the requirements for the practical implementation and ongoing maintenance of the redefined kilogram - Davidson, Stuart; Berry, James; Silvestri, Zaccari; Hogstrom, Richard; Green, Richard (IMEKO 22nd TC3, 12th TC5 and 3rd TC22 International Conferences, 2014)
The unit of mass, the kilogram, is the last of the seven base units of the International System of Units (SI) to be defined in terms of a material artefact rather than by relation to an invariant of nature. Progress is being made towards a redefinition in terms of the Planck constant (h), realised via the watt balance and Avogadro experiments. This paper describes the results of investigations to develop mass standards compatible with use in vacuum, and methods for the transfer, storage and cleaning of these standards in order to satisfactorily implement and disseminate the kilogram redefinition.
Keywords: Cleaning; Kilogram; Redefinition; Storage; Transfer; Vacuum

Hybrid fiber laser – arc welding of high strength low alloy steel - Cao, X.J.; Wanjara, P.; Bernard, A.; Pudo, D.; Munro, C.; Nolting, A.E. (Materials Science Forum, 2014)
High strength low alloy (HSLA) grade 80 (HSLA-80) steel with a thickness of 9.1-mm was successfully welded in a single pass using a 5-kW fiber laser combined with an arc welding process. It was found that the maximum gap size in the Y-groove butt joint configuration should remain below 0.2 mm for a 9.1-mm section thickness. Sound butt joints with no welding cracks but some minor microporosity were successfully obtained. However, an underfill defect was frequently observed on the top surface of the weldments. Underfilling could be mitigated through increasing the filler wire addition so as to exceed the groove volume; however, due to significant evaporation and expulsion of the molten pool at the high laser power density, the underfill defect would be difficult to fully eliminate. At slow cooling rates, slight softening in the heat affected zone (HAZ) was present in the mid-thickness region but its elimination is possible at high welding speeds.
Keywords: Butt Joint; HSLA-80 Steel; Hybrid Laser-Arc Welding; Weldability

Evaluation of algal biomass and biodiesel co-products for bioenergy applications - Nicol, R. W.; Lamers, A.; Lubitz, W. D.; Mcginn, P. J. (Journal of Biobased Materials and Bioenergy, 2014)
Several forms of energy, such as hydrogen gas, butanol, biogas, and ethanol can be produced from renewable, biological resources. However, many bioenergy technologies are currently at the lab scale and the list of commercial operations successfully producing bioenergy in Canada is much shorter. Currently, Canada's bioenergy production is dominated by biofuels such as ethanol and biodiesel, biomass for combustion and the use of anaerobic digesters for biogas production. Bioenergy production in Canada is relatively new, especially in comparison to other renewable energy technologies like hydroelectricity, and therefore opportunities exist to improve bioenergy's economic and environmental impact. One route for improvement is through the valorization of co-products, and our efforts to use fungi to convert biodiesel wastewater and biodiesel derived crude glycerol to the value-added product single cell oil is reviewed. Wastewater is generated during biodiesel production through water washing of the unfinished biodiesel, and COD values for biodiesel wastewater are reported to range from approximately 31,000 to 590,000 mg L-1 . Glycerol is generated in biodiesel production during the tranesterification reaction of intact triacylglycerol molecules with an alcohol and a strong base. This glycerol is a crude co-product, and can contain high levels of methanol, residual oils and water. Cultivation of the newly described oleaginous fungus Galactomyces geotrichum in 50 g L-1 crude glycerol, 10 g L-1 casein and 200 mL L-1 biodiesel wastewater yielded fungal biomass with an average single cell oil content of 51.1%. We also review our data on the use of microalga Nannochloropsis granulata as a feedstock for anaerobic digestion. This work was completed in a 2.2 m3 pilot anaerobic digester and is unique as it is much larger in scope than the vast majority of literature sources reporting on the use of algae in anaerobic digestion applications. The use of N. granulata as a co-digestion substrate with swine manure reduced the methane yield as compared to swine manure alone. Algal biomass added at 0.5 kg volatile solids per day, 1.1 kg volatile solids per day and 1.6 kg volatile solids per day reduced methane yield by 48.4%, 55.9% and 64.7% respectively. The observed reductions may have been due to inhibitory metabolites produced during algal digestion or because of recalcitrance of the algal cell wall. The digester inoculum was not pre-adapted to microalgae degradation and this may have also played a role. Use of algal biomass as a feedstock for anaerobic digestion is still in its infancy, and biomass pre-treatments, different algal strains or different digestion techniques could be needed for the successful utilization of algae. Microalgae have other positive attributes including the ability to remediate waste streams and recycle nutrients as well act as a single source for multiple products and more research is needed in order to successfully exploit this versatile feedstock.
Keywords: Anaerobic Digestion; Biodiesel Wastewater; Bioenergy in Canada; Biogas; Crude Glycerol; Galactomyces geotrichum; Nannochloropsis granulate

Impact of overlapping trajectories in laser micro-polishing - Chow, M. T. C.; Knopf, G.; Bordatchev, E. V. (Proceedings of the 2014 International Symposium on Optometchatronic Technologies, 2014)
The quality of a laser micro-polished (LμP) surface is dependent upon the part material, initial surface topography and roughness, and the energy density of the beam used to produce a thin molten layer on the finished part. Prior research has shown that the amount of energy delivered to the work piece can also be controlled by adjusting the “focal offset distance” (FOD) of the laser optics. In this paper, the impact of using multiple overlapping trajectories for laser polishing on the average surface roughness (Ra) is investigated. The analysis is performed on ball-end micromilled H13 tool steel specimens polished using a nanosecond Q-switched Nd:YAG laser. The initial surface roughness is dependent on the height and width of micromilled scallops. The trajectory overlap percentage (TO%) is an advanced machining parameter used to describe the ratio between the size of the polishing step and the molten LμP diameter. The average surface roughness of the “best” experimental specimen was reduced from a Ra of 746 nm to 205 nm (~73% improvement) using a short distance polishing regime (1.3 mm <; FOD <; 1.8 mm) with a TO% = 96.8% (or 2 μm step trajectory). Similar, but less dramatic, reductions in profile Ra were also observed for the longer polishing regime (FOD > 2.2 mm). The experiments also illustrate that the quality of the final surface finish can be further improved by combining continuous wave laser polishing (CW-LP) and LμP.

Biomodal dwell-fatigue Weibull distribution of forged titanium IMI 834 - Toubal, Lotfi; Bocher, Philippe; Moreau, André (International Journal of Damage Mechanics, 2014)
This study addresses cumulative damage and its evolution during the cold dwell fatigue of a near-alpha titanium alloy. An experimental study was undertaken to examine the evolution of life, strain, strength and damage of 13 titanium IMI 834 samples cut from a single disk forging. The samples were tested in the same dwell-fatigue loading conditions. In the dwell phase, the load is maintained at 80% of ultimate tensile strength (824 MPa, 90% of yield strength) for thirty seconds. The secant Young's modulus and inelastic strain at minimum load were measured in order to document the evolution of the irreversible damage against the number of cycles for all specimens. Experimental observations show significant differences in dwell-fatigue life and damage behavior. This mechanical analysis and an analysis of the cumulative Weibull reliability distribution suggest a bimodal dwell-fatigue failure process. Some features of the mechanical behavior can be used to sort the samples according to each of the two failure modes and improve the reliability of the fatigue test campaign.
Keywords: titanium alloy; dwell-fatigue; bimodal Weibull distribution; damage, strain

Exploring the chemical space for rare-earth additions to optimize aerospace alloys - Mercier, P. H. J.; Rodgers, J. R. (Materials Science and Technology 2013 Conference Proceedings, 2014)
We have embarked upon building a database of the calculated physical, electrical, optical and magnetic properties of known rare earth element (REE) alloys and compounds using computational methods. These methods, in materials research, offer powerful tools to provide fundamental understanding of the behaviors of materials and to support the selection and design of materials that meet application requirements. With advances in computational science and information technology in recent years, materials research and development are shifting from the empirical approaches to the design to achieve optimal functionality based on integrated computational-prediction and experimental-validation methods. REE additions to non-ferrous metal alloys improve their physical and mechanical properties, resulting in lightweight and high strength alloys with special application in the aerospace industry. Physical property results will be presented on (i) a number of binary REE-alloys families and (ii) on the use of rare-earths in improving the mechanical properties of lightweight alloys.
Keywords: materials informatics; rare earth elements; ab initio calculations; aerospace alloys

Bilingual sentiment consistency for statistical machine translation - Chen, Boxing; Zhu, Xiaodan (EACL 2014, 2014)
In this paper, we explore bilingual sentiment knowledge for statistical machine translation (SMT). We propose to explicitly model the consistency of sentiment between the source and target side with a lexicon-based approach. The experiments show that the proposed model significantly improves Chinese-to-English NIST translation over a competitive baseline. © 2014 Association for Computational Linguistics.
Keywords: Lexicon-based; Statistical machine translation; Computational linguistics

Monitoring strategy for characterization of airborne nanoparticles - Niu, J.; Rasmussen, P.; Magee, R.; Nilsson, G. (Nanotechnology 2014: Graphene, CNTs, Particles, Films and Composites, 2014)
A major challenge in monitoring indoor exposures to nanoparticles is the selection and effective use of suitable instrumentation. Comparability, portability, response time, and reliability are important selection criteria in addition to reasonable cost. Amongst these criteria, instrument comparability is especially critical due to the requirement for multiple instruments in a single exposure assessment and the lack of reference standards for instrument calibration. Testing and verifying instrument comparability, therefore, is essential to ensure the reliability of exposure assessment data. In this study, a variety of portable and non-portable direct-reading instruments, including scanning mobility particle sizers, condensation particle counters, aerodynamic particle sizers, diffusion charger and aerosol mass monitors, were deployed simultaneously. Instrument performance was evaluated in a room-sized environmentally-controlled chamber with the goal of recommending a suite of instruments to provide particle number, surface area, particle size distribution and mass measurements with an acceptable level of uncertainty. The instrumental strategy was then applied to monitoring background aerosols in a typical workplace setting, where laser printers provided a point source for monitoring response time and comparing peak-to-background signals. The study also explored filter-based methods for collecting nanoparticles for subsequent elemental analysis using inductively-coupled plasma mass spectroscopy (ICP-MS).
Keywords: Background characterization; CPC; ICP-MS; Instrument comparison; Nanoparticle exposures; Sampling; Size distribution; SMPS

Hybrid fiber laser-arc welding of 10-mm thick Ca6Nm stainless steel - Mirakhorli, Fatemeh; Cao, Xinjin; Pham, Xuan-Tan; Wanjara, Priti; Fihey, Jean-Luc (Materials Science and Technology Conference and Exhibition 2014, 2014)
Single pass butt welds were successfully manufactured using a 5.2 kW fiber laser in tandem with arc welding to join 10-mm thick plates of CA6NM, a low carbon martensitic stainless steel in cast form that is widely used for hydroelectric turbines. The joint integrity was evaluated in terms of the weld geometry, discontinuities, microstructure and mechanical properties (tensile and Charpy impact) in both the as-welded and post-weld tempered conditions. Though visible cracks were absent, some defects such as porosity and underfill were observed. The as-welded fusion zone consisted mainly of lath martensite and residual delta ferrite; the latter transformed to tempered lath martensite after post-weld tempering. Four distinct heat affected zones were identifiable through characterization of the microstructure and hardness evolution. Evaluation of the mechanical properties indicated acceptable tensile strength in both the as-welded and post-weld tempered conditions, though the latter was critical for attaining acceptable Charpy impact energy values.
Keywords: CA6NM cast stainless steel; Defects; Hybrid laser-arc welding (HLAW); Mcrostructure; Mechanical properties.; Post-weld heat treatment; Tempering

Sentiment analysis of short informal texts - Kiritchenko, Svetlana; Zhu, Xiaodan; Mohammad, Saif M. (Journal of Artifcial Intelligence Research, 2014)
We describe a state-of-the-art sentiment analysis system that detects (a) the sentiment of short informal textual messages such as tweets and SMS (message-level task) and (b) the sentiment of a word or a phrase within a message (term-level task). The system is based on a supervised statistical text classification approach leveraging a variety of surface-form, semantic, and sentiment features. The sentiment features are primarily derived from novel high-coverage tweet-specific sentiment lexicons. These lexicons are automatically generated from tweets with sentiment-word hashtags and from tweets with emoticons. To adequately capture the sentiment of words in negated contexts, a separate sentiment lexicon is generated for negated words. The system ranked first in the SemEval-2013 shared task `Sentiment Analysis in Twitter' (Task 2), obtaining an F-score of 69.02 in the message-level task and 88.93 in the term-level task. Post-competition improvements boost the performance to an F-score of 70.45 (message-level task) and 89.50 (term-level task). The system also obtains state-of-the-art performance on two additional datasets: the SemEval-2013 SMS test set and a corpus of movie review excerpts. The ablation experiments demonstrate that the use of the automatically generated lexicons results in performance gains of up to 6.5 absolute percentage points.
Keywords: Classification (of information); Semantics; Text processing; Ablation experiments; Automatically generated; Percentage points; Sentiment analysis; Sentiment features; Sentiment lexicons; State-of-the-art

High performance lubricants for demanding PM applications - St-Laurent, Sylvain; Thomas, Yannig; Azzi, Lhoucine (Fenmo Yejin Jishu/Powder Metallurgy Technology, 2014)
The achievement of high density at reasonable cost is without a doubt one of the major ques of the P/M industry. Hish density can be achieved through various processing mutes involving the shaping of the part and/or the sintering. In particular, single pressing methods such as warm compaction and die wall lubrication are known to give green density in the range of 7.2 to 7.5 g·cm-3 depening on the powder formulation. Nevertheless, these pressing techniques normally require tighter control, are costly and may reduce productivity compared to conventional pressing method. More recently, new high performance lubricants were developed to achieve higher green density than conventional lubricant by cold compaction or temperature-controlled die compaction. This paper presents the green and sintered characteristics of these newly developed high performance lubricants in a laboratory and production scale. In particular, the compaction and ejection characteristics of these new lubricants ale compared to that obtained with other conventional lubricants.
Keywords: Lubicants; PM parts

Vacuum-bag-only prepreg processing of honeycomb structures : from lab-scale experiments to an aircraft demonstrator - Kratz, J.; Genest, M.; Preau, M.; Hubert, P. (International SAMPE Technical Conference, 2014)
An aircraft demonstrator was manufactured using out-of-autoclave prepreg and vacuum-bag-only processing techniques. The demonstrator featured flat, double-curvature, joggles, abrupt geometry changes, and honeycomb inserts. The scientific literature was used to assess and mitigate the processing risks for this demonstrator. Low through-thickness gas permeability and ply-bridging in small radii corners were thought to be the most significant risks. The through-thickness permeability of the target material was undetectable, therefore spiking was used to increase gas evacuation. Unfortunately, the available mould had small radii that could not be increased, as a result ply bridging was observed in these corners. Miniature pressure sensors were successfully embedded in the demonstrator to monitor the honeycomb core pressure throughout the lay-up, including intermittent de-bulking, the pre-cure vacuum hold, and the elevated temperature cure. The sensors identified two insightful process phenomena: 1) gas evacuation increased with additional plies, and 2) non-uniform pressure response was observed in the part during cure. Visible part quality was acceptable, excluding small radii geometrical features. Internal part quality (voidage) was estimated using pulsed infrared thermography non-destructive-evaluation. While void contents are not exact, the thermography revealed local voidage can vary significantly over the part.
Keywords: Curing; Gas permeability; Risk assessment; Thermography (imaging); Elevated temperature; Geometrical features; Non-uniform pressures; Out of autoclaves; Processing technique; Scientific literature; Through-thickness; Through-thickness permeability

Identification of aeroelastic parameters for helicopter tail rotor limit cycle oscillation monitoring - Chen, Yong; Wickramasinghe, Viresh; Zimcik, David G. (International Conference on Adaptive Structures and Technologies, 2014)
The aeroelastic parameters of helicopter tail rotors are required in the monitoring and evaluation of rotor aeroservoelastic instability incidents such as limit cycle oscillations (LCO). However, in-situ measurement of these parameters on helicopters is generally difficult due to the need to transfer vibration data across a rotating interface. This paper presents a novel center frequency scaling factor relationship of the aeroelastic parameters between the rotating and stationary frames. Together with the stochastic parameter identification technique, this methodology enables real-time estimation and tracking of the critical aeroelastic parameters in the rotating frame during LCO events based on vibration information measured exclusively in the stationary frame. The methodology has been validated using flight vibration data measured from both the rotating and stationary frames of a helicopter tail rotor system during an LCO event. Moreover, this methodology has been applied to the analysis of vibration data measured from the teeter tail rotor system on the Canadian CH-149 Cormorant helicopters to derive the critical aeroelastic parameters during several LCO events.
Keywords: Aeroelasticity; Aeroservoelasticity; Fighter aircraft; Helicopter rotors; Helicopters; Identification (control systems); Stochastic systems; Vibration analysis; Center frequency; In-situ measurement; Limit Cycle Oscillation

Canadian photonics : the foundation for a quantum leap - Decker, Jennifer; Tennant, John; Sussman, Ben (Optics and Photonics News, 2014)
Stakeholders at the national and local levels are committed to advancing the field of quantum technologies in Canada. Canada is a world leader in photonics research and development, and continues that trend in the emerging field of quantum technologies. Deeply rooted in photonics, quantum technologies utilize unusual quantum features to build technologies and devices radically different than is possible with traditional physics. Canadian photonics “firsts” include the development of the fiber Bragg grating in 1978, high-speed data transport (10 Gbit), as well as the breakthrough invention of the quantum key distribution protocol in 1984.

Direct impact sound insulation of cross laminate timber floors with and without toppings - Zeitler, Berndt; Schoenwald, Stephan; Sabourin, Ivan (International Congress on Noise Control Engineering: Improving the World Through Noise Control, 2014)
Cross Laminated Timber (CLT), which is well suited for construction of tall buildings, is becoming a more popular construction material in North America. However, to ensure comfortable living conditions, sound insulation measures are necessary. The study presented here compares results of direct impact sound insulation of 5- and 7-ply CLT floors covered with different a concrete toppings on various interlayers. Improvements of up to 21dB in Weighted Normalized Impact Sound Pressure Level (Ln,w) were observed using a newly proposed reference floor for CLTs. Furthermore, the improvements of floor coverings on CLT floors are compared to those achieved on other types of construction, such as the reference concrete floor. The improvements of Ln,w tend to be higher on the concrete floors than on the CLT floors tested. These and other findings will be presented.
Keywords: Impact Sound; Insulation; CLT; reference curve

Modelling of mechanical properties of randomly oriented strands thermoplastic composites - Selezneva, M.; Meldrum, S.; Roy, S.; Lessard, L.; Yousefpour, A. (European Conference on Composite Materials, 2014)
Randomly oriented strands (ROS) thermoplastic composites have attractive properties, such as great formability and high modulus, but their properties are highly variable due to heterogeneous macrostructure. This paper proposes a stochastic finite element technique that predicts strength and modulus of ROS composites. It is based on the concept of random strands generation to model variability, and it utilizes Hashin's failure criteria and fracture energies to estimate strength. Overall, the model matches experimental results and shows that failure of ROS composites is matrix-dominated and follows the "weakest-link" principle.
Keywords: Mechanical properties; Randomly oriented strands; Thermoplastics

Numerical simulations of ice forces on moored and thruster-assisted drillships - Sayed, Mohamed; Kubat, Ivana; Wright, Brian; Millan, Jim (Offshore Technology Conference OTC 2014, 2014)
The present work examines the loads on moored/DP-assisted drillships and their responses in managed pack ice. Numerical simulations are used to determine deformations and stresses within the ice cover and the movements of the vessel. The results give ice forces and moments on the vessel, as well as its surge, sway and yaw responses. The drillship assumed in this simulation work has a length of 230 m, a beam of 42 m, and a mass of 100,000 Mt. Simulations examine a case representing a moored vessel in a managed ice field consisting of 50 m floes that are 1 m in thickness, moving at a constant speed of 0.3 m/s. For ice moving along the surge direction, the peak surge force was approximately 2 MN. The corresponding maximum surge was 1.5 m. A parametric study further examines several aspects of ice interaction with the vessel. The results quantify various effects of ice management (the role of floe size), ice thickness and drift speed, the direction of ice movement, and stiffness of the mooring system. A case of combined mooring and thruster-assisted mooring is also examined. The additional contribution of the thrusters (or control of the DP system) is shown to somewhat reduce the offsets of the vessel. The work presents a methodology for evaluating the stationkeeping performance of vessels in managed pack ice and quantifying the role of the mooring/DP system characteristics.

Compression molding of composite tailboom frames - Roy, Steven; Yousefpour, Ali; Bednar, Felix; Beaulieu, Pete (AHS 70th Annual Forum, 2014)
Composite helicopter tailboom frames were manufactured by compression molding using a carbon fiber thermoset bulk molding compound. A mold was designed for compression molding and installed in a hydraulic press. The mold features two shear edges, guide pins and an integrated part ejection system. A material preforming method was developed to improve consistency in material distribution, which improved process robustness. A number of parts were produced and inspected for void content and dimensional stability. No significant porosity or voids were found in the samples examined. Part thickness uniformity was studied and improved, in order to meet the required tolerances. Dimensional inspection before and after a free standing post cure showed no significant part distortion. This work showed that compression molded tailboom frames are a viable alternative to current tailboom frames using continuous pre-impregnated fabric materials and cured by autoclave. This alternate processing method has the potential to reduce touch time and manufacturing costs.
Keywords: Carbon fibers; Curing; Helicopters; Hydraulic machinery; Molds; Bulk molding compounds; Dimensional inspection; Improved process; Manufacturing cost; Material distribution; Pre-impregnated fabrics; Processing method; Thickness uniformity; Compression molding

Knowing the limits of a trend : examining the onset of asymptotic stable fracture behaviour in mode II fatigue delamination growth - Rans, C. D.; Atkinson, J.; Li, C. (European Conference on Composite Materials, 2014)
This study is motivated by the possibility that experimental data sets, particularly those obtained at high R-ratios, may unknowingly contain data points within the asymptotic stable fracture region that influence its perceived log-linear behaviour and the fit of various loglinear delamination growth models. Results from the experimental investigation indicate that the asymptotic stable fracture region can extend to GIImax values as low as 0.7GIIc.
Keywords: asymptotic behaviour; Delamination growth; Fatigue; Mode II

An empirical study on the effect of negation words on sentiment - Zhu, Xiaodan; Guo, Hongyn; Mohammad, Saif; Kiritchenko, Svetlana (Annual Meeting of the Association for Computational Linguistics, 2014)
Negation words, such as no and not, play a fundamental role in modifying sentiment of textual expressions. We will refer to a negation word as the negator and the text span within the scope of the negator as the argument. Commonly used heuristics to estimate the sentiment of negated expressions rely simply on the sentiment of argument (and not on the negator or the argument itself). We use a sentiment treebank to show that these existing heuristics are poor estimators of sentiment. We then modify these heuristics to be dependent on the negators and show that this improves prediction. Next, we evaluate a recently proposed composition model (Socher et al., 2013) that relies on both the negator and the argument. This model learns the syntax and semantics of the negator's argument with a recursive neural network. We show that this approach performs better than those mentioned above. In addition, we explicitly incorporate the prior sentiment of the argument and observe that this information can help reduce fitting errors.
Keywords: Neural networks; Semantics; Composition model; Empirical studies; Fitting error; Recursive neural networks; Treebanks; Computational linguistics

Enhanced transmission and beam confinement using bullseye plasmonic lenses at THz frequencies - Heggie, Tanner J.; Naylor, David A.; Gom, Brad G.; Bordatchev, Evgueni V. (Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications VII, 2014)
A major limitation in terahertz (THz) imaging applications is the relatively poor diffraction limited spatial resolution. A common approach to achieve subwavelength resolution is near-field imaging using a subwavelength aperture, but the low transmission efficiency through the aperture limits the sensitivity of this method. Bullseye structures, consisting of a single subwavelength circular aperture surrounded by concentric periodic corrugations, have been shown to enhance transmission through subwavelength apertures. At optical wavelengths, the fabrication of bullseye structures has been traditionally achieved by lithographic or chemical processes. Since the scale of plasmonic structures depends on the incident wavelength, precision micromilling techniques are well suited for THz applications. In this paper we describe a diamond micromilling process for the fabrication a plasmonic lenses operating at 325 GHz. Theoretical simulations are obtained using an FDTD solver and the performance of the lens is measured using a customized THz test bed.
Keywords: Plasmonics; bullseye lens; terahertz; micromilling; subwavelength imaging; surface plasmons

A new approach to building acoustics regulation in Canada - Zeitler, Berndt; Schoenwald, Stephan; Quirt, David (43rd International Congress on Noise Control Engineering: Improving the World through Noise Control, 2014)
A new approach to the control of sound transmission is among the proposed changes in the 2015 edition of the National Building Code of Canada. The design objective is changing from a minimum STC for the wall or floor/ceiling assembly separating adjacent units to a requirement for the Apparent Sound Transmission Class (ASTC) including flanking. The approach to design is based on combining the ASTM data from conventional laboratory measurement of direct transmission through wall or floor/ceiling assemblies with measurements of flanking transmission conforming to ISO 10848 and predictions using ISO 15712-1. To support the design and regulatory approval process, the National Research Council is preparing a series of reports detailing the design procedure for a broad range of heavy monolithic and lightweight framed constructions, and providing the supporting generic data in form of web-based tools and tables from two decades of research studies in flanking test laboratories.
Keywords: Sound; Insulation; Transmission; Flanking

AFP monocoque composite tailboom full scale fatigue testing - Beltempo, André; Rogers, John E.; Rutledge, Robert S.; Colle, Alain R.; Drouin, Pierre; Lapalme, Maxime (Forum 70 : Americam Helicopter Society, 2014)
This paper describes two phases of full scale testing performed on a Bell Helicopter Textron Canada Limited (BHTCL) composite monocoque tailboom manufactured using Automated Fiber Placement (AFP). This technical demonstrator tailboom was designed for use on a Bell 407 model as part of a collaboration program with Bombardier Inc., Composite Atlantic Ltd. and the National Research Council Canada (NRC). The tailboom cone consisted of a skin made from an AFP layup of carbon epoxy fiber tape combined to a hand layup made from fabric. The skin is then bonded to six hand layup frames. The fatigue test objectives were to validate the component to flaw tolerant safe life requirements and establish damage tolerance to light and medium caliber ballistic impacts. The test article, containing embedded flaws, impact damages, and representative repairs, was subjected to a full four lifetime fatigue test at NRC. All testing during this phase was conducted at 250 °F ‘hot-dry’ conditions to simulate operating temperatures seen in service. The test article successfully sustained four lifetimes of fatigue testing, followed by residual strength testing to both limit and ultimate loads. In the second phase of the full scale testing, the article was subjected to six ballistic impacts with deadweights replicating a critical load condition in the field, interspersed with short ‘go-home’ fatigue cycling in the laboratory. Regular inspections and near-real-time data analyses were performed throughout testing. No permanent deformation, new damage or existing damage growth was sustained by the tested composite components during the fatigue tests, subsequent residual strength tests, or fatigue loads following ballistic impact, thereby proving the flaw and damage tolerance capability of the structure.

Parametric study of direct airborne insulation of wood stud walls in midrise construction - Zeitler, Berndt; Schoenwald, Stefan; King, Frances (International Congress on Noise Control Engineering: Improving the World through Noise Control, 2014)
There has been a proposal in Canada to increase the maximum allowable height of wood framed construction in the National Building Code of Canada (NBCC) from 4 stories to 6 stories. Design of taller buildings will lead to a change in the details of the walls that have to withstand the higher axial and lateral loads. However, also requirements of other building physics disciplines, one of those being the sound insulation, still have to be met. In the study presented here various assemblies that meet the higher load requirements are compared for direct airborne sound insulation. Parameters that were modified include: sheathing membranes, stud arrangement, stud depth, and resilient channels. Some of the wall design variants that work well structurally have very poor sound insulation properties and most of them require the use of resilient channels to obtain somewhat acceptable sound insulation properties. These and more results will be presented here.
Keywords: sound, insulation, transmission

Manufacturing of composite helicopter tailboom using AFP process - Chen, Jihua; Octeau, Marc-Andre; Roy, Steven; Yousefpour, Ali; Gingras, Richard; Beaulieu, Pete; Morris, Kevin (Forum 70 : American Helicopter Society, 2014)
This paper briefly summarizes the manufacturing process of a composites helicopter tailboom prototype, with the focus on improving quality and productivity as well as reducing manufacturing cost. The ultimate goal of the project is to develop a stable and reliable automated fiber placement process for mass production of the composite tailboom. For this purpose, different fiber path generation scenarios were first explored in the early stage of the project. Information such as fiber angle deviations, gaps and overlaps were collected. Feedback was provided to the designers to further improve the tailboom design. Second, since fiber placement process is influenced by different variables, including layup speed, compaction force, heater temperature, humidity level, etc., the interactions of different process parameters were investigated. The optimum layup speed was identified under different conditions. Third, to achieve the quality requirements, methodologies were developed to reduce machine downtime and to track and repair manufacturing defects. As a result of the project, a one-piece, fiber placed composites tailboom was successfully manufactured.

Gene-based SNP discovery and genetic mapping in pea - Sindhu, Anoop; Ramsay, Larissa; Sanderson, Lacey-Anne; Stonehouse, Robert; Li, Rong; Condie, Janet; Shunmugam, Arun S.K.; Liu, Yong; Jha, Ambuj B.; Diapari, Marwan; Burstin, Judith; Aubert, Gregoire; et al. (Theoretical and Applied Genetics, 2014)
Pea (Pisum sativum L.) is one of the world’s oldest domesticated crops and has been a model system in plant biology and genetics since the work of Gregor Mendel. Pea is the second most widely grown pulse crop in the world following common bean. The importance of pea as a food crop is growing due to its combination of moderate protein concentration, slowly digestible starch, high dietary fiber concentration, and its richness in micronutrients; however, pea has lagged behind other major crops in harnessing recent advances in molecular biology, genomics and bioinformatics, partly due to its large genome size with a large proportion of repetitive sequence, and to the relatively limited investment in research in this crop globally. The objective of this research was the development of a genome-wide transcriptome-based pea single-nucleotide polymorphism (SNP) marker platform using next-generation sequencing technology. A total of 1,536 polymorphic SNP loci selected from over 20,000 non-redundant SNPs identified using deep transcriptome sequencing of eight diverse Pisum accessions were used for genotyping in five RIL populations using an Illumina GoldenGate assay. The first high-density pea SNP map defining all seven linkage groups was generated by integrating with previously published anchor markers. Syntenic relationships of this map with the model legume Medicago truncatula and lentil (Lens culinaris Medik.) maps were established. The genic SNP map establishes a foundation for future molecular breeding efforts by enabling both the identification and tracking of introgression of genomic regions harbouring QTLs related to agronomic and seed quality traits.
Keywords: Pisum sativum L.; genetic mapping

A preliminary ventilation rate study for residential buildings and offices based on VOC emission database - Ye, W.; Zhang, X.; Won, D. (International Conference on Indoor Air Quality and Climate, 2014)
Scenarios involving four standard rooms and different material loadings were analyzed to study adequate ventilation rates for residential buildings and offices. The study followed the IAQ procedure recommended by ASHRAE. The emission source data were from the National Research Council Canada (NRC) database. The building material emissions and VOC concentrations were predicted by using the concept of characteristic emission factor. The ventilation rate was calculated for seven scenarios to meet the thresholds given by six indoor air quality standards. The results show that the ventilation rate depends heavily on the selected standard and material loading ratio. The dominating chemical substance in determining ventilation rate in various cases is not unique. The time to take for the emission to complete was about to 3 to 7 years for all seven cases. The typical ventilation rate was about 1 h-1 for living room, bedroom and private room, and was 3.2 h-1 for open office.
Keywords: building material; characteristic emission rate; standard room; ventilation rate

Molecular dynamics simulations of hydrogen bonding in clathrate hydrates with ammonia and methanol guest molecules - Alavi, Saman; Shin, Kyuchul; Ripmeester, John A. (Journal of Chemical and Engineering Data, 2014)
We performed molecular dynamics simulations of the ammonia and methanol-based clathrate hydrates with the emphasis on characterizing hydrogen-bonding interactions of these guest molecules with the water lattice. Systems studied include structure II (sII) binary clathrate hydrates of tetrahydrofuran (THF) (large cage, L) + NH3 (small cage, S) and THF (L) + CH3OH (S), the structure I (sI) pure NH3 (L), pure CH3OH (L), the binary NH3 (L) + CH4 (S), and binary CH3OH (L) + CH4 (S) clathrate hydrates. We simulated these clathrate hydrates with the transferable intermolecular potential with four point changes (TIP4P) water potential and the TIP4P/ice water potential to determine the effect of the water potential on the predicted hydrogen bonding of the guest molecules. Simulations show that, despite strongly hydrogen bonding with the framework water molecules, clathrate hydrate phases with NH3 and CH3OH can be stable within temperatures ranges up to 240 K. Indeed, a limited number of thermodynamic integration free energy calculations show that both NH3 and CH3OH molecules give more stable guest-host configurations in the large sI clathrate hydrate cages than methane guests. Predictions of hydrogen bonding from simulations with the two different water potentials used can differ substantially. To study the effect of proton transfer from water to the basic NH3 guests, simulations were performed on a binary NH3 + CH4 sI clathrate hydrate where less than 10 % of the ammonia guests in the large cages were converted to NH4 + and a water molecule of the hydrate lattice in the same large cage was converted to OH-. The small percentage of proton transfer to ammonia guests in the large cages did not affect the stability of the resultant hydrate. The structural perturbations in the lattice that result from this proton transfer are characterized.
Keywords: Ammonia; Free energy; Gas hydrates; Hydration; Hydrogen; Methane; Methanol; Molecular dynamics; Molecules; Organic solvents; Proton transfer; Binary clathrate hydrates; Clathrate hydrate; Free-energy calculations; Hydrogen bonding interactions; Intermolecular potentials; Molecular dynamics simulations; Structural perturbation; Thermodynamic integration; Hydrogen bonds

A regenerating ultrasensitive electrochemical impedance immunosensor for the detection of adenovirus - Lin, Donghai; Tang, Thompson; Harrison, D. Jed; Lee, William E.; Jemere, Abebaw B. (Biosensors and Bioelectronics, 2014)
We report on the development of a regenerable sensitive immunosensor based on electrochemical impedance spectroscopy for the detection of type 5 adenovirus. The multi-layered immunosensor fabrication involved successive modification steps on gold electrodes: (i) modification with self-assembled layer of 1,6-hexanedithiol to which gold nanoparticles were attached via the distal thiol groups, (ii) formation of self-assembled monolayer of 11-mercaptoundecanoic acid onto the gold nanoparticles, (iii) covalent immobilization of monoclonal anti-adenovirus 5 antibody, with EDC/NHS coupling reaction on the nanoparticles, completing the immunosensor. The immunosensor displayed a very good detection limit of 30 virus particles/ml and a wide linear dynamic range of 105. An electrochemical reductive desorption technique was employed to completely desorb the components of the immunosensor surface, then re-assemble the sensing layer and reuse the sensor. On a single electrode, the multi-layered immunosensor could be assembled and disassembled at least 30 times with 87% of the original signal intact. The changes of electrode behavior after each assembly and desorption processes were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy techniques.
Keywords: Cyclic voltammetry; Desorption; Electrochemical electrodes; Fiber optic sensors; Gold; Metal nanoparticles; Nanoparticles; Self assembled monolayers; Spectroscopy; Viruses; X ray photoelectron spectroscopy; 11-mercaptoundecanoic acid; Adenovirus; Covalent immobilization; Electrochemical impedance; Linear dynamic ranges; Modified electrodes; Reductive desorption; Self-assembled layers; Electrochemical impedance spectroscopy; gold nanoparticle; undecanoic acid; virus antibody; chemical modification; chemical reaction; concentration (parameters); controlled study; cyclic potentiometry; electrochemical impedance spectroscopy; electrode; immobilization; immunosensor; limit of detection; virus detection; Human adenovirus type 5

Numerical modelling complements physical testing in staged design of ocean wave-driven pump - Boileau, Renee; Raman-Nair, Wayne; Graham, Michael (2014 Oceans - St. John's, OCEANS 2014, 2014)
National Research Council Canada (NRC) is collaborating with College of the North Atlantic (CNA) to develop an ocean wave-driven pump to supply the CNA shore-based aquaculture centre in Lord's Cove, Newfoundland. NRC provides a combination of physical model testing under controlled laboratory conditions and computer simulation using numerical modelling tools developed at NRC and commercial software. The CNA plans to demonstrate the sustainability of a shore-based aquaculture centre in the context of rural Newfoundland. The efficiency of the centre depends in part on its energy consumption, a major part of which is supplying seawater to a facility some distance from the ocean and above sea level. The development of a seawater supply pump driven by the power of ocean waves would reduce the electrical costs for the centre. The NRC is supporting a staged design program through numerical and physical model testing to select a robust design optimized for the local sea conditions at the Lord's Cove mooring site. The wave pump is inspired by designs for wave energy converters. But since wave energy converters have not converged on a single design, there are major risks and costs in designing a wave pump, from construction and testing of physical models for competing designs to mooring failure and potential loss of the device in the hurricane-force storms typical of southern Newfoundland. Using lessons learned in the energy sector, risks can be mitigated by systematically testing the behaviour and response of proposed concepts through a staged design program, starting from characterizing the hydrodynamic characteristics of a simplified model through progressively larger, more complex physical and numerical models used in functional tests. This approach systematically directs the design process toward a single prototype optimized for performance in specified wave conditions using scaled model tests in advance of the most costly stage of sea trials. The goals of the staged design program for the CNA wave-driven pump are to • evaluate various design concepts • select a design suited to the CNA mooring site • optimize the design for a typical sea state and • specify a mooring robust enough to keep the platform on station during the sometimes extreme sea states at Lord's Cove. The program began with characterization of the chosen mooring site outside Lord's Cove. Processed wave buoy data from this site informed the estimation of mooring line loads using numerical tools developed by NRC and typical sea states on which to focus design optimization. In the second stage, a numerical tool was developed to estimate pump output and validated against test results for a physical pump. In the third stage, various wave pump platform design concepts were evaluated based on estimation of hydrodynamic characteristics. The designs were characterized using a combination of physical model tests in the NRC 200-metre wave tank in St. John's and computer simulations using Ansys Aqwa and Matlab. A sample pump platform design is shown as a scale model and a numerical mesh in Fig. 1. In the fourth stage, which will precede a full-scale prototype deployment at sea, a design has been selected and an operational scale model wave pump platform has been tested in the NRC wave facilities. Numerical modelling is used to choose a mooring for the full-scale deployment. In this staged design program, the use of physical model tests and computer simulation are complementary methods used alternatively to solve potentially costly and time-consuming problems. A selection of the problems encountered in the design of the wave pump platform is presented along with a critique of the solutions applied by NRC to build confidence in a wave-driven pump design tailored for the CNA site.
Keywords: Aquaculture; Energy utilization; Fluid dynamics; Hydrodynamics; MATLAB; Mooring; Numerical models; Ocean currents; Oceanography; Sea level; Seawater; Site selection; Stages; Water waves; Wave power; Complementary methods; Controlled laboratories; Hurricane-force storm; Hydrodynamic characteristics; National Research Council; Numerical and physical modeling; Physical model testing; Wave energy converters; Wave energy conversion

Sensor dynamics in high dimensional phase spaces via nonlinear transformations: Application to helicopter loads monitoring - Valdes, Julio J.; Cheung, Catherine; Li, Matthew (IEEE SSCI 2014 - 2014 IEEE Symposium Series on Computational Intelligence - CIDM 2014: 2014 IEEE Symposium on Computational Intelligence and Data Mining, Proceedings, 2014)
Accurately determining component loads on a helicopter is an important goal in the helicopter structural integrity field, with repercussions on safety, component damage, maintenance schedules and other operations. Measuring dynamic component loads directly is possible, but these measurement methods are costly and are difficult to maintain. While the ultimate goal is to estimate the loads from flight state and control system parameters available in most helicopters, a necessary step is understanding the behavior of the loads under different flight conditions. This paper explores the behavior of the main rotor normal bending loads in level flight, steady turn and rolling pullout flight conditions, as well as the potential of computational intelligence methods in understanding the dynamics. Time delay methods, residual variance analysis (gamma test) using genetic algorithms, unsupervised non-linear mapping and recurrence plot and quantification analysis were used. The results from this initial work demonstrate that there are important differences in the load behavior of the main rotor blade under the different flight conditions which must be taken into account when working with machine learning methods for developing prediction models.
Keywords: Aircraft control; Data mining; Delay control systems; Genetic algorithms; Helicopter services; Helicopters; Mathematical transformations; Phase space methods; Time delay; Computational intelligence methods; High dimensional phase space; Machine learning methods; Maintenance schedules; Measurement methods; Non-linear transformations; Nonlinear mappings; Quantification analysis; Flight control systems

Numerical study of soot formation in laminar coflow diffusion flames of methane doped with primary reference fuels - Consalvi, Jean-Louis; Liu, Fengshan; Contreras, Jorge; Kashif, Muhammad; Legros, Guillaume; Shuai, Shijin; Wang, Jianxin (Combustion and Flame, 2014)
Laminar methane diffusion flames doped by vapors of different blends of n-heptane and iso-octane burning in a coflow of air diluted with CO2 were simulated numerically in this study. These laminar coflow diffusion flames have been experimentally investigated recently by Kashif et al. (2014). Numerical simulations were performed using a detailed reaction model containing 175 species and 1189 reactions together with a sectional soot model. The soot model consists of inception as a result of the collision of two pyrene molecules, heterogeneous surface growth and oxidation following the hydrogen abstraction acetylene addition (HACA) mechanism, soot particle coagulation, and PAH surface condensation. The numerical model provides prediction in fairly good quantitative agreement with the experimental data and reproduces successfully the influence of the fuel blend composition and CO2 dilution of air on the flame structure and soot production. The soot production increases and decreases linearly with the molar concentration of iso-octane in the fuel stream and CO2 content of the air stream, respectively. In addition, the efficiency of CO2 dilution to suppress soot is reduced as the concentration of iso-octane increases. This is likely due to the greater contributions of PAH condensation with increasing iso-octane concentration relative to soot surface growth through HACA. The increase in soot production with the molar concentration of iso-octane results primarily from an increase in the concentration of propargyl radical. The self-reaction of propargyl then produces higher concentrations of benzene and pyrene, leading to higher nucleation rates and consequently an increase the soot surface area. The higher surface area then results in higher surface growth and condensation rates. The enhanced pyrene concentration is another factor to prompt soot surface condensation. An analysis of the reaction rates shows that propargyl radicals are mainly produced from propylene. The decomposition and oxidation of iso-octane was found much more efficient to produce propylene than that of n-heptane.
Keywords: Atmospheric composition; Carbon dioxide; Condensation; Diffusion; Polycyclic aromatic hydrocarbons; Polyols; Reaction rates; Coflow diffusion flames; Detailed reaction model; Heterogeneous surface; Hydrogen abstraction; Primary reference fuels; Quantitative agreement; Surface condensation; Dust; fuel; heptane; methane; propylene; pyrene; chemical model; controlled study; decomposition; diffusion coefficient; dilution; environmental temperature; flame; flow rate; laminar coflow diffusion flame; laminar flow; oxidation; particle size; quantitative study; reaction analysis; refraction index; soot; soot formation; surface property; thermal diffusion

Spatial and temporal variability of incidental nanoparticles in indoor workplaces: Impact on the characterization of point source exposures - Niu, Jianjun; Rasmussen, Pat E.; Magee, Robert; Nilsson, Gregory (Environmental Sciences: Processes and Impacts, 2014)
This study deployed a suite of direct-reading instruments in six locations inside one building to characterize variability of the background aerosol, including incidental nanoparticles (NP), over a six month period. The instrument suite consisted of a portable Condensation Particle Counter (CPC) and a Scanning Mobility Particle Sizer (SMPS) for assessing particle number concentrations and size distributions in the nano-scale range; an Aerodynamic Particle Sizer (APS) for assessing micron-scale particle number concentrations and size distributions; plus a desktop Aerosol Monitor (DustTrak DRX) and a Diffusion Charger (DC2000CE) for assessing total particle mass and surface area concentrations respectively. In terms of number concentration, NPs (<100 nm) were the dominant particles observed in the background aerosol, contributing up to 53-93% of the total particle number concentrations. The particle size distributions were bimodal with maxima around 19-79 nm and 50-136 nm, respectively, depending on workplace locations. The average detected background particle number, surface area and total mass concentrations were below 7.1 × 103 # cm-3, 22.9 μm2 cm-3 and 33.5 μg m-3, respectively in spring samples and below 1.8 × 103 # cm-3, 10.1 μm2 cm-3 and 12.0 μg m-3, respectively in winter samples. A point source study using an older model laser printer as the emission source indicated that NPs emitted from the investigated printer were distinguishable from background. However, more recent low emitting printers are likely to be indistinguishable from background, and chemical characterization (e.g. VOCs, metals) would be required to help identify emission sources.
Keywords: nanoparticle; aerosol; air pollutant; air monitoring; ambient air; molecular weight; occupational exposure; particle size; seasonal variation; spring; surface property; winter; work environment; workplace; chemical model; environmental monitoring; exposure; indoor air pollution; Inhalation Exposure; Models, Chemical

An integrated creep-fatigue theory for material damage modeling - Wu, Xijia (Key Engineering Materials, 2014)
This paper presents an integrated creep-fatigue (ICF) theory to describe the non-linear creep-fatigue interaction during thermo-mechanical loading. The ICF theory recognizes the damage evolution as a holistic process consisting of nucleation and propagation of surface or subsurface cracks in coalescence with internally distributed damage, leading to final fracture. In a polycrystalline material under combined cyclic and dwell loading, crack nucleation and propagation occurs by fatigue or oxidation mechanisms, whereas internally distributed damage often occurs in the form of grain boundary cavities or microcracks due to creep or dwell effects, particularly at high temperatures. Based on the above mechanism, a damage evolution equation is mathematically derived, and the generality of the above physical mechanisms warrants the applicability of the ICF theory over a wide range of stresses and temperatures. This paper uses Mar-M 509, a cobalt base superalloy, as an example to illustrate how the ICF theory describes creep and low cycle fatigue (LCF).
Keywords: Algorithms; Cracks; Creep; Grain boundaries; Nucleation; Polycrystalline materials; Cobalt-base superalloys; Creep-fatigue interactions; Damage evolution equation; Life predictions; Material damage model; Oxidation mechanisms; Thermo-mechanical loading; Fatigue damage

Effect of wind and current on course control of a maneuvering vessel - Raman-Nair, Wayne; Gash, Robert; Sullivan, Michael (OCEANS 2014 MTS/IEEE, 2014)
The equations of motion of a maneuvering vessel under the action of wind, current, rudder and propulsion are solved by the MATLAB Runge-Kutta solver ode45. The hydrodynamic derivatives used are those presented by Clarke et al. (1982)[1]. Wind and current loads are applied to segments of the vessel via a relative velocity formulation and drag coefficients. Course control is achieved by autopilot gains derived from a first order Nomoto approximation. The intent is to provide a tool for assessing a vessel's maneuvering capabilities in terms of a simple single parameter (track deviation) under various environmental conditions. Results of simulations are presented for various wind and current scenarios.
Keywords: Electric currents; MATLAB; Runge Kutta methods; Wind; Current loads; Environmental conditions; Hydrodynamic derivatives; maneuvering; Maneuvering capability; Relative velocity; Single parameter; track deviation; Equations of motion

Preservation of cognitive performance with age during exertional heat stress under low and high air velocity - Wright Beatty, Heather E.; Keillor, Jocelyn M.; Hardcastle, Stephen G.; Boulay, Pierre; Kenny, Glen P. (BioMed Research International, 2014)
Older adults may be at greater risk for occupational injuries given their reduced capacity to dissipate heat, leading to greater thermal strain and potentially cognitive decrements. Purpose. To examine the effects of age and increased air velocity, during exercise in humid heat, on information processing and attention. Methods. Nine young (24 ± 1 years) and 9 older (59 ± 1 years) males cycled 4 × 15 min (separated by 15 min rest) at a fixed rate of heat production (400 W) in humid heat (35°C, 60% relative humidity) under 0.5 (low) and 3.0 (high) m · s-1 air velocity wearing coveralls. At rest, immediately following exercise (end exercise), and after the final recovery, participants performed an abbreviated paced auditory serial addition task (PASAT, 2 sec pace). Results. PASAT numbers of correct responses at end exercise were similar for young (low = 49 ± 3; high = 51 ± 3) and older (low = 46 ± 5; high = 47 ± 4) males and across air velocity conditions, and when scored relative to age norms. Psychological sweating, or an increased sweat rate with the administration of the PASAT, was observed in both age groups in the high condition. Conclusion. No significant decrements in attention and speeded information processing were observed, with age or altered air velocity, following intermittent exercise in humid heat.
Keywords: adult; age; cardiovascular response; cognition; controlled study; exercise; heat stress; humidity; male; normal human; sweating; task performance; thermogenesis

Heat release rate variations in a globally stoichiometric, stratified iso-octane/air turbulent V-flame - Vena, Patrizio C.; Deschamps, Béatrice; Guo, Hongsheng; Smallwood, Gregory J.; Johnson, Matthew R. (Combustion and Flame, 2014)
Combustion intensity variations along a globally stoichiometric, stratified iso-octane/air turbulent V-flame were measured in the presence of four different equivalence ratio gradients and compared to a reference fully-premixed case. Instantaneous heat release rate (HRR) images were obtained from the simultaneous acquisition of OH and CH2O Planar Laser Induced Fluorescence (PLIF) images, providing the first direct estimates of local heat release rate in a stratified, iso-octane/air turbulent flame. Detailed numerical simulations were conducted to validate the use of (OH LIF)(CH2O LIF) for measurements of HRR in iso-octane/air flames over a broad range of equivalence ratios. Flame images were analyzed for specific mean equivalence ratio gradient effects for near stoichiometric flame regions within a fixed mean equivalence ratio range of 0.95≤ϕ≤1.05. The location of the interrogation window, or region of interest (ROI), was obtained through 3-pentanone tracer PLIF of the reactants and ensured that any observed variation could be attributed specifically to mean equivalence ratio gradient effects, rather than simple mixture strength effects. Results showed small but measurable, decreases in the mean HRR for near stoichiometric flame regions within the ROI as the gradient was varied, and differences of up to 4.4% relative to the reference premixed case were directly attributable to the imposed mean ϕ gradient, separate from potential effects of local mixture strength. By contrast, general stratification effects were also considered for flames of comparable global equivalence ratios but with much broader ranges of mixture strength, and results showed offsetting effects of increased 2D flame length (up to ~17%) and decreased HRR per flame length (up to ~22%), resulting in small variations in the overall HRR of ~9%. The present analysis suggests that gradient effects on local flame properties may differ significantly from general stratification effects in which different ranges of mixture strengths are present, and separating these aspects of partially premixed combustion is critical to the proper interpretation of data, where both may be relevant in different applications.
Keywords: Equivalence classes; Fluorescence; Image segmentation; Laser optics; Laser produced plasmas; Polyols; Equivalence ratio gradient; Stratified combustion; Turbulent combustion; V flames; Combustion; 3 pentanone; alkanone; fluorescent dye; formaldehyde; hydroxide; isooctane; octane; combustion; fire and fire related phenomena; flame; flammability; fluorescence imaging; heat release rate; planar laser induced fluorescence; stoichiometry; temperature measurement; temperature sensitivity; turbulent flow; validation study

Dynamic feature modelling for closed-loop machining process control of complex parts - Liu, Changqing; Li, Yingguang; Shen, Weiming (International Journal of Computer Integrated Manufacturing, 2014)
Dynamically changing machining conditions and uncertain manufacturing resource availability are forcing manufacturing enterprises to implement advanced process planning and control systems with an adaptive machining information model in order to increase productivity and ensure product quality. This article proposes a dynamic feature modelling method for closed-loop machining process control of complex parts. A software platform is developed to include feature modelling software units with algorithms to represent and integrate geometric, machining, inspection and monitoring information and a service software unit with algorithms to update dynamic feature information and trigger online inspection. A multi-thread execution approach and a finite state machine method are adopted to support the execution and collaboration of multiple algorithms for dynamic feature modelling. A sharing memory approach is utilised for real-time communication between software units and the computer numerical control (CNC) kernel. The dynamic feature model is highly informative and can support autonomous decision-making and bidirectional information flow. By implementing the proposed dynamic feature modelling, a closed-loop process machining control including the integration of process planning, machining, inspection and monitoring for complex parts can be achieved.
Keywords: Adaptive control systems; Algorithms; Closed loop control systems; Computer control; Computer control systems; Inspection; Logic circuits; Machining; Machining centers; Monitoring; Quality control; Closed loops; Closed-loop machining; Computer numerical control; Dynamic features; Manufacturing enterprise; Manufacturing resource; Monitoring information; Real-time communication; Process control

Time-dependent mass transport for O2 reduction at the Pt | perfluorosulfonic acid ionomer interface - Novitski, David; Xie, Zhong; Holdcroft, Steven (ECS Electrochemistry Letters, 2014)
Chronoamperometric analysis of the oxygen reduction reaction (ORR) at Pt microelectrode | perfluorosulfonic acid (PFSA) ionomer interfaces in a solid state electrochemical cell reveals an increase in both the oxygen diffusion coefficient (Db) and oxygen permeability (Dbcb) upon consecutive potential step measurements. From a vapor-equilibrated, electrochemically unperturbed state under conditions of 70% RH and 50°C, Db and Dbcb increased by factors of 2 and 1.5, respectively. Db and Dbcb return to their initial values after resting the electrode at the open circuit potential. The electrochemical generation of water is believed responsible for the time-dependent mass transport parameters of ORR.
Keywords: Diffusion; Electrodes; Electrolytic reduction; Ionomers; Lanthanum compounds; Microelectrodes; Oxygen; Platinum; Reduction; Electrochemical Generation; Open circuit potential; Oxygen diffusion coefficients; Oxygen reduction reaction; Perfluorosulfonic acid; Perfluorosulfonic acid ionomers; Potential step measurements; Solid-state electrochemical cells; Interface states

Density functional theory study of the effects of substituents on the carbon-13 nuclear magnetic resonance chemical shifts of asphaltene model compounds - Oliveira, Jackeline S. C.; Da Costa, Leonardo M.; Stoyanov, Stanislav R.; Seidl, Peter R. (Energy and Fuels, 2014)
Petroleum asphaltenes are a complex mixture of organic molecules containing mainly fused polyaromatic and naphthenic systems and pendant chains, polar moieties with heteroatoms (S, N, and O), and transition metals. A variety of spectroscopic techniques has been employed to characterize asphaltenes, but their structures remain largely elusive because of the complexity, variety of samples, and assignment limitations. Carbon-13 nuclear magnetic resonance (13C NMR) spectroscopy has contributed extensively to asphaltene characterization. However, proper assignment of 13C NMR spectra is very challenging because spectra of natural asphaltenes feature a large number of peaks in unusual environments, which may be hard to assign and interpret. We employ the dispersion-corrected ωB97X-D density functional with 6-31G(d,p) basis set to rationalize common trends in the 13C NMR chemical shifts of asphaltene model compounds. The calculated 13C NMR chemical shifts for a calibration series of 14 aromatic and heterocyclic reference compounds containing C atoms of types similar to those in the asphaltene model compounds are found to correlate linearly with the respective experimental values. The linear fitting yields a correlation coefficient of R2 = 0.99 and absolute errors of less than 10 ppm. Moreover, we calculate and calibrate the 13C chemical shifts of asphaltenes extracted from Brazilian vacuum residues to analyze and correlate the C atom types with those of the reference compounds. It is found that the presence of heteroatoms as well as environments with a high aromatic condensation index can significantly affect the chemical shifts. The effect of heteroatoms on the chemical shift, a situation that has scarcely been addressed in the literature, is evaluated here in detail. The results are intended to help interpret 13C NMR spectra and allow for a more complete characterization of asphaltene molecules.
Keywords: Aromatic compounds; Asphaltenes; Carbon; Chemical analysis; Chemical compounds; Chemical shift; Density functional theory; Molecules; Nuclear magnetic resonance spectroscopy; Transition metals; Correlation coefficient; Experimental values; Nuclear magnetic resonance chemical shifts; Petroleum asphaltenes; Reference compounds; Spectroscopic technique; Nuclear magnetic resonance

Comparison of sample digestion techniques for the determination of trace and residual catalyst metal content in single-wall carbon nanotubes by inductively coupled plasma mass spectrometry - Grinberg, Patricia; Sturgeon, Ralph E.; Diehl, Liange de O.; Bizzi, Cezar A.; Flores, Erico M. M. (Spectrochimica Acta - Part B Atomic Spectroscopy, 2014)
A single-wall carbon nanotube material produced by laser ablation of renewable biochar in the presence of Ni and Co catalyst was characterized for residual catalyst (Co and Ni) as well as trace metal impurity content (Fe, Mo, Cr, Pb and Hg) by isotope dilution ICP-MS following sample digestion. Several matrix destruction procedures were evaluated, including a multi-step microwave-assisted acid digestion, dry ashing at 450 C and microwave-induced combustion with oxygen. Results were benchmarked against those derived from neutron activation analysis and also supported by solid sampling continuum source GF-AAS for several of the elements. Although laborious to execute, the multi-step microwave-assisted acid digestion proved to be most reliable for recovery of the majority of the analytes, although content of Cr remained biased low for each approach, likely due to its presence as refractory carbide.
Keywords: Activation analysis; Carbides; Carbon nanotubes; Catalysts; Inductively coupled plasma mass spectrometry; Isotopes; Laser ablation; Lead; Mass spectrometers; Mass spectrometry; Mercury (metal); Molybdenum; Neutron activation analysis; Nickel; Trace analysis; Trace elements; ICP-MS; Metal content determination; Microwave-assisted acid digestion; Microwave-induced combustion; Ni and co catalysts; SWCNT; Trace metal impurities; Single-walled carbon nanotubes (SWCN)

Peanut shell hybrid sodium ion capacitor with extreme energy-power rivals lithium ion capacitors - Ding, Jia; Wang, Huanlei; Li, Zhi; Cui, Kai; Karpuzov, Dimitre; Tan, Xuehai; Kohandehghan, Alireza; Mitlin, David (Energy and Environmental Science, 2014)
This is the first report of a hybrid sodium ion capacitor (NIC) with the active materials in both the anode and the cathode being derived entirely from a single precursor: peanut shells, which are a green and highly economical waste globally generated at over 6 million tons per year. The electrodes push the envelope of performance, delivering among the most promising sodiation capacity-rate capability-cycling retention combinations reported in the literature for each materials class. Hence the resultant NIC also offers a state-of-the-art cyclically stable combination of energy and power, not only in respect to previously but also as compared to Li ion capacitors (LICs). The ion adsorption cathode based on Peanut Shell Nanosheet Carbon (PSNC) displays a hierarchically porous architecture, a sheet-like morphology down to 15 nm in thickness, a surface area on par with graphene materials (up to 2396 m2 g-1) and high levels of oxygen doping (up to 13.51 wt%). Scanned from 1.5-4.2 V vs. Na/Na+ PSNC delivers a specific capacity of 161 mA h g-1 at 0.1 A g-1 and 73 mA h g-1 at 25.6 A g-1. A low surface area Peanut Shell Ordered Carbon (PSOC) is employed as an ion intercalation anode. PSOC delivers a total capacity of 315 mA h g-1 with a flat plateau of 181 mA h g-1 occurring below 0.1 V (tested at 0.1 A g-1), and is stable at 10000 cycles (tested at 3.2 A g-1). The assembled NIC operates within a wide temperature range (0-65 °C), yielding at room temperature (by active mass) 201, 76 and 50 W h kg-1 at 285, 8500 and 16500 W kg-1, respectively. At 1.5-3.5 V, the hybrid device achieved 72% capacity retention after 10000 cycles tested at 6.4 A g-1, and 88% after 100000 cycles at 51.2 A g-1.
Keywords: Capacitors; Carbon; Cathodes; Electrodes; Metal ions; Oilseeds; Shells (structures); Capacity retention; Hierarchically porous; Ion intercalation; Li-ion capacitors; Lithium-ion capacitors; Single precursors; adsorption; ion; lithium; power generation; sodium; surface area; Arachis hypogaea

CuPc:C60 nanocomposite: a pathway to control organic microstructure and phase transformation - Stock, Taylor J. Z.; Ogundimu, Tolu; Baribeau, Jean-Marc; Lu, Zheng-Hong; Nogami, Jun (Physica Status Solidi (B) Basic Research, 2014)
Growth and thermal behavior of copper-phthalocyanine (CuPc) and fullerene (C60) organic nanocomposite thin films, grown on SiO2 and Cu(111) surfaces, have been studied using scanning electron microscopy, X-ray diffraction (XRD) and scanning tunneling microscopy (STM). It is found that the growth of pure CuPc organic thin films follows an island-type growth mode. The island formation is found to be dramatically suppressed by the inclusion of C60 during deposition. XRD and STM studies reveal that the CuPc molecular packing is altered upon C60 inclusion, producing disordered CuPc-C60 interfaces. The ordered molecular stacking of CuPc is found to be disrupted completely when C60 concentration reaches 30wt.%. The thermal stability of the CuPc thin film has been significantly improved upon C60 inclusion. It is suggested that the molecular diffusion kinetics rather than thermodynamics are responsible for the improved stability.

Waveguide sub-wavelength structures: a review of principles and applications - Halir, Robert; Bock, Przemek J.; Cheben, Pavel; Ortega-Moñux, Alejandro; Alonso-Ramos, Carlos; Schmid, Jens H.; Lapointe, Jean; Xu, Dan-Xia; Wangüemert-Pérez, J. Gonzalo; Molina-Fernández, Íñigo; Janz, Siegfried (Laser and Photonics Reviews, 2014)
Periodic structures with a sub-wavelength pitch have been known since Hertz conducted his first experiments on the polarization of electromagnetic waves. While the use of these structures in waveguide optics was proposed in the 1990s, it has been with the more recent developments of silicon photonics and high-precision lithography techniques that sub-wavelength structures have found widespread application in the field of photonics. This review first provides an introduction to the physics of sub-wavelength structures. An overview of the applications of sub-wavelength structures is then given including: anti-reflective coatings, polarization rotators, high-efficiency fiber-chip couplers, spectrometers, high-reflectivity mirrors, athermal waveguides, multimode interference couplers, and dispersion engineered, ultra-broadband waveguide couplers among others. Particular attention is paid to providing insight into the design strategies for these devices. The concluding remarks provide an outlook on the future development of sub-wavelength structures and their impact in photonics.
Keywords: Anti reflective coatings; Athermal waveguides; Broadband waveguides; Dispersion engineering; Grating couplers; Sub-wavelength structures; Waveguide crossings; Wavelength demultiplexers

Intelligent thermal control of resistance welding of fiberglass laminates for automated manufacturing - Zammar, Imad Ali; Mantegh, Iraj; Huq, M. Saiful; Yousefpour, Ali; Ahmadi, Mojtaba (IEEE/ASME Transactions on Mechatronics, 2014)
A novel approach to automate large-scale resistance welding of thermoplastic composite materials, based on real-time temperature control, is presented in this paper. Resistance welding, a kind of fusion bonding, is a widespread alternative process to mechanical fastening and adhesive bonding in joining thermoplastic composites. A second-order linear observer was identified to estimate the online temperature at the weld interface. A fuzzy logic controller (FLC) was designed to control the weld temperature using both process voltage and linear weld speed as the control inputs and using the temperature estimate as the feedback signal. The FLC was implemented in real time with the experimental setup using an industrial robot - KUKA KR 210. The closed-loop controller was capable of successfully controlling the weld temperature within 10% of the desired temperature, resulting in superior weld quality when compared to open-loop results. The results thus affirm the suitability of the control strategy for large-scale automated welding.
Keywords: Automation; Composite materials; Controllers; Fuzzy control; Fuzzy logic; Intelligent control; Laser beam welding; Reinforced plastics; Resistance welding; Thermoplastics; Welding; Welds; Automated Manufacturing; Closed loop controllers; Fuzzy logic controllers; Intelligent Manufacturing; Intelligent thermal controls; Thermoplastic composite; Thermoplastic composite material; Welding automation

Geniposide protects pancreatic INS-1E β cells from hIAPP-induced cell damage: potential involvement of insulin degrading-enzyme - Zhang, Yonglan; Yin, Fei; Liu, Jianhui; Wang, Yanwen (Cell Biology International, 2014)
Islet amyloid deposition is increasingly seen as a pathogenic feature of type 2 diabetes mellitus (T2DM), with the deposits containing the unique amyloidogenic peptide islet amyloid polypeptide (IAPP, also known as amylin). The fibril precursors of IAPP contribute to its cytotoxicity on pancreatic β cells and be important in causing β-cell dysfunction in T2DM. However, the development of effective this study, inhibitors against the toxicity of IAPP has been extremely challenging. We have found that pre-incubation with geniposide dose-dependently prevented human IAPP (hIAPP)-induced cell damage in INS-1E cells, and bacitracin, an inhibitor of IDE activity, prevented significantly the protective effects of geniposide in pancreatic INS-1E cells significantly. Geniposide induced the expression of insulin-degrading enzyme (IDE), a key degrading protein of hIAPP, but had no significant effect on the aggregation of hIAPP. These findings indicate that geniposide prevents hIAPP-induced cytotoxicity in INS-1E cells involving upregulation of IDE expression.
Keywords: geniposide; insulinase; animal cell; cell damage; cell mediated cytotoxicity; cell protection; concentration response; controlled study; drug mechanism; enzyme activity; gene expression regulation; nonhuman; pancreas islet beta cell; protein aggregation; rat; upregulation

A computational study on the steric effects of naphthenic moieties on aggregation interactions of nonconventional petroleum constituents - Seidl, Peter R.; Oliveira, Jackeline S. C.; Da Costa, Leonardo M.; Stoyanov, Stanislav R. (Journal of Physical Organic Chemistry, 2014)
Nonconventional oil is usually heavy and extra heavy crude or light oil that is relatively unstable. This oil contains varying proportions of larger, more aromatic constituents rather than molecules that can be distilled directly into fuels and petrochemicals. We perform density functional theory (ωB97X-D/6-31G(d,p)) calculations to study the contributions of steric effects and dispersion interactions in a series of dimers and trimers of model hydrocarbons containing fused aromatic and cyclohexyl (referred to in the petroleum literature as naphthenic) rings. The aggregation behavior of these molecules is analyzed in terms of the optimized geometry, atomic charges, interaction enthalpy (ΔH), and Gibbs free energy (ΔG298). The ΔH and ΔG298 values show that all the dimerization and trimerization processes are exothermic, and only a few are spontaneous at 298 K. The naphthenic hydrogen atoms have a key role in the orientation of the monomers in dimer and trimer aggregates. The interaction among naphthenic hydrogen atoms belonging to adjacent monomers causes steric repulsion. The interaction of naphthenic hydrogen atoms with the π-electronic clouds of aromatic rings in adjacent molecules causes attraction. In both cases, the naphthenic hydrogen atoms cause deviation of the monomer from the initial parallel displaced configuration in dimers and trimers. These results reflect the importance of naphthenic rings and their steric interactions in determining the relationship between structures of nonconventional petroleum constituents and their tendency to aggregate and cause fouling.
Keywords: Aggregates; Aromatic compounds; Aromatic hydrocarbons; Aromatization; Atoms; Computation theory; Density functional theory; Free energy; Gibbs free energy; Hydrogen; Monomers; Oil shale; Oligomers; Aggregation behavior; Aromatic rings; Computational studies; DFT calculation; Dispersion interaction; Interaction enthalpies; Optimized geometries; Steric interactions; Dimers

The core and O-polysaccharide structure of the Caulobacter crescentus lipopolysaccharide - Jones, Michael D.; Vinogradov, Evgeny; Nomellini, John F.; Smit, John (Carbohydrate Research, 2014)
Here we describe the analysis of the structure of the lipopolysaccharide (LPS) from Caulobacter crescentus strain JS1025, a derivative of C. crescentus CB15 NA1000 with an engineered amber mutation in rsaA, leading to the loss of the protein S-layer and gene CCNA-00471 encoding a putative GDP-l-fucose synthase. LPS was isolated using an aqueous membrane disruption method. Polysaccharide and core oligosaccharide were produced by mild acid hydrolysis and analyzed by nuclear magnetic resonance spectroscopy and chemical methods. Spectra revealed the presence of two polysaccharides, one of them, a rhamnan, could be removed using periodate oxidation. Another polymer, built from 4-amino-4-deoxy-d-rhamnose (perosamine), mannose, and 3-O-methyl-glucose, should be the O-chain of the LPS according to genetic data. The attribution of the rhamnan as a part of LPS or a separate polymer was not possible.
Keywords: Chemical analysis; Gene encoding; Nuclear magnetic resonance; Chemical method; Core oligosaccharide; Extracellular polysaccharides; Lipopolysaccharides; Mild acid hydrolysis; O-polysaccharide structure; Periodate oxidation; 3 methylglucose; 4 amino 4 deoxy d rhamnose; guanosine diphosphate fucose; guanosine diphosphate fucose synthase; lipopolysaccharide; mannose; O antigen; oligosaccharide; periodate; polysaccharide; rhamnose; bacterial polysaccharide; bacterium lipopolysaccharide; perosamine; rhamnan; carbohydrate analysis; Caulobacter crescentus; hydrolysis; membrane damage; oxidation; proton nuclear magnetic resonance; carbohydrate synthesis; Caulobacter vibrioides

A 3D wave model to simulate the interaction of wave field in the presence of multi-structures - Zaman, M. Hasanat; Winsor, Fraser (2014 Oceans - St. John's, OCEANS 2014, 2014)
A 3D dispersive numerical model has been developed and utilized to study the interacted wave field in the Offshore Engineering Basin (OEB) of National Research Council Canada in the presence of array of structures. The basic physics of the numerical model follows the concept of the depth averaged velocity distribution along with an enhanced dispersion relation. The Alternating Direction Implicit (ADI) algorithm has been employed for the solution of the governing equations. As an application, the model has been used to study the wave propagation in the presence of different combinations of structures where the effects due to the reflection and diffraction are also incorporated. Relevant experiments are carried out in the OEB. Total 10 wave probes are deployed to measure the data at different locations in the Basin. Later the numerical results are compared with the experimental results in the OEB at different probe locations for different wave and structure conditions. The comparisons of the numerical results show great agreement with the experimental results. In this paper the results for regular waves will only be presented and discussed.
Keywords: Dispersions; Numerical models; Probes; Wave propagation; Alternating direction implicit; Combinations of structures; Depth-averaged velocity distributions; Dispersion relations; Interaction of waves; Offshore engineering basins; Structure conditions; Dispersion (waves)

Host fate is rapidly determined by innate effector-microbial interactions during acinetobacter baumannii bacteremia - Bruhn, Kevin W.; Pantapalangkoor, Paul; Nielsen, Travis; Tan, Brandon; Junus, Justin; Hujer, Kristine M.; Wright, Meredith S.; Bonomo, Robert A.; Adams, Mark D.; Chen, Wangxue; Spellberg, Brad (Journal of Infectious Diseases, 2014)
Acinetobacter baumannii is one of the most antibiotic-resistant pathogens. Defining mechanisms driving pathogenesis is critical to enable new therapeutic approaches. Methods. We studied virulence differences across a diverse panel of A. baumannii clinical isolates during murine bacteremia to elucidate host-microbe interactions that drive outcome. Results. We identified hypervirulent strains that were lethal at low intravenous inocula and achieved very high early, and persistent, blood bacterial densities. Virulent strains were nonlethal at low inocula but lethal at 2.5-fold higher inocula. Finally, relatively avirulent (hypovirulent) strains were nonlethal at 20-fold higher inocula and were efficiently cleared by early time points. In vivo virulence correlated with in vitro resistance to complement and macrophage uptake. Depletion of complement, macrophages, and neutrophils each independently increased bacterial density of the hypovirulent strain but insufficiently to change lethality. However, disruption of all 3 effector mechanisms enabled early bacterial densities similar to hypervirulent strains, rendering infection 100% fatal. Conclusions. The lethality of A. baumannii strains depends on distinct stages. Strains resistant to early innate effectors are able to establish very high early bacterial blood density, and subsequent sustained bacteremia leads to Toll-like receptor 4-mediated hyperinflammation and lethality. These results have important implications for translational efforts to develop therapies that modulate host-microbe interactions.
Keywords: Acinetobacter baumannii; bacteremia; bacterial clearance; bacterial strain; bacterial virulence; bacterium identification; bacterium isolate; cell transport; growth rate; host pathogen interaction; in vitro study; in vivo study; inoculation; molecular dynamics; Acinetobacter infection; C3H mouse; immunology; innate immunity; macrophage; microbiology; multidrug resistance; neutrophil; organismal interaction; virulence; antiinfective agent; virulence factor; Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Mice, Inbred C3H; Microbial Interactions

Assessment of life saving appliances regulatory requirements - Human factors knowledge gaps - Power, Jonathan; Ré, António Simões (2014 Oceans - St. John's, OCEANS 2014, 2014)
Life saving appliances are used throughout Canada and around the world every day by a large number of individuals who work or travel over open water. Personnel rely on these life saving appliances to help provide protection from harsh environments, and reduce the risk of injury or death in the event of a marine accident. Due to their importance in helping to save lives at sea, life saving appliances are built and tested according to specific standards and regulations to ensure that they provide the level of performance required. Unfortunately, life saving appliances do not always perform as expected which can lead to unexpected injuries or loss of life. Given that life saving appliances must meet specific performance goals as prescribed by standards and regulations, it is often these goals that fall short of what is actually needed during a marine accident. A knowledge gap is created when the testing conditions, as outlined in a standard or regulation, do not accurately reflect those conditions found during a marine accident. As a result, a life saving appliance will often meet performance goals that are below those required to prevent an injury or loss of life during an actual marine accident. The Canadian regulation: 'Life Saving Equipment Regulations' C.R.C., c. 1436 was reviewed and possible knowledge gaps with respect to human factors were identified. The goals and requirements for life saving appliances in the regulation were compared against existing work done in the area of marine safety to determine if what was prescribed adequately reflected what could be found during a marine accident. There were many gaps identified in the regulation, commonly caused by prescriptive wording specifying conditions not commonly found during a marine accident. These knowledge gaps will widen as conditions become more severe than what is prescribed in the regulations possibly leading to even further decrease in life saving appliance performance than what is already measured.
Keywords: Human engineering; Harsh environment; Knowledge gaps; Lifesaving appliances; Marine accidents; Marine safety; regulations; Regulatory requirements; Testing conditions; Accidents

Ship performance monitoring and analysis to improve fuel efficiency - Mak, Lawrence; Sullivan, Michael; Kuczora, Andrew; Millan, James (2014 Oceans - St. John's, OCEANS 2014, 2014)
A pilot project was launched to monitor vessel performance and to explore ways to reduce fuel consumption. A prototype Vessel Performance Monitoring and Analysis System (VPMAS) was used to collect information over a three week period. The project objective was to collect needed data, conduct preliminary analysis to establish trends, explore key performance indicators (KPI) to establish baseline, and explore data products for performance management. Performance management includes improving vessel performance and supporting efficient operation to reduce fuel consumption. For the pilot project, only a subset of vessel performance data was collected. Current key performance indicators (KPIs) include fuel consumption per trip, fuel consumption per distance travelled, fuel consumption per displacement distance and fuel consumption per payload distance. The dataset will expand in the future and will include the effect of environmental conditions. Preliminary analysis includes comparing the normal route for calm sea states and irregular routes taken probably to avoid heavy sea states; assessing the maneuvers in and out of harbors, computing key performance indicators, assessing the data trends and general statistics, and identifying data products to support performance management. Initial results show that automatic fuel measurement was in good agreement with manual tank sounding. A voyage on an irregular route consumed almost twice the amount of fuel consumed in a normal route. Fuel consumption would be reduced if constant speed is used in open water and if deviations from the desired routes could be minimized, for example, through optimized autopilot.
Keywords: Benchmarking; Ocean currents; Environmental conditions; General statistics; Key performance indicators; Performance management; Performance monitoring and analysis; Preliminary analysis; Project objectives; Prototype vessels; Fuels

Morphology of supported polymer electrolyte ultrathin films: a numerical study - Borges, Daiane Damasceno; Gebel, Gerard; Franco, Alejandro A.; Malek, Kourosh; Mossa, Stefano (The Journal of Physical Chemistry C, 2014)
Morphology of polymer electrolytes membranes (PEM), e.g., Nafion, inside PEM fuel cell catalyst layers has a significant impact on the electrochemical activity and transport phenomena that determine cell performance. In those regions, Nafion can be found as an ultrathin film, coating the catalyst and the catalyst support surfaces. The impact of the hydrophilic/hydrophobic character of these surfaces on the structural formation of the films has not been sufficiently explored yet. Here, we report an extensive molecular dynamics simulation investigation of the substrate effects on the ionomer ultrathin film morphology at different hydration levels. We use a mean-field-like model that we introduced in previous publications for the interaction of the hydrated Nafion ionomer with a substrate, characterized by a tunable degree of hydrophilicity. We show that the affinity of the substrate with water plays a crucial role in the molecular rearrangement of the ionomer film, resulting in completely different morphologies. Detailed structural description in different regions of the film shows evidence of strongly heterogeneous behavior. A qualitative discussion of the implications of our observations on the PEMFC catalyst layer performance is finally proposed.
Keywords: Catalyst supports; Catalysts; Electrolytes; Fuel cells; Hydration; Hydrophilicity; Ionomers; Molecular dynamics; Morphology; Polymer films; Proton exchange membrane fuel cells (PEMFC); Solid electrolytes; Ultrathin films; Electrochemical activities; Hydrophilic/hydrophobic; Molecular dynamics simulations; Molecular rearrangement; Polymer electrolyte; Structural descriptions; Structural formation; Transport phenomena; Polyelectrolytes

A multi-view two-level classification method for generalized multi-instance problems - Wang, Xiaoguang; Liu, Xuan; Matwin, Stan; Japkowicz, Nathalie; Guo, Hongyu (2014 IEEE International Conference on Big Data (Big Data), 2014)
Multi-instance (MI) learning is different than standard propositional classification, as it uses a set of bags containing many instances as input. While the instances in each bag are not labeled, the bags themselves are, as positive or negative. In this paper, we present a novel multi-view, two-level classification framework to address the generalized multi-instance problems. We first apply supervised and unsupervised learning methods to transform a MI dataset into a multi-view, single meta-instance dataset. Then we develop a multi-view learning approach that can integrate the information acquired by individual view learners on the meta-instance dataset from the previous step, and construct a final model. Our empirical studies show that the proposed method performs well compared to other popular MI learning methods.
Keywords: Big data; Unsupervised learning; Classification framework; Classification methods; Empirical studies; Learning methods; Multi-instance problems; Multi-view learning; Multi-views; Supervised and unsupervised learning; Learning systems

Multi-scale investigation of the performance of limestone in concrete - Bentz, Dale P.; Ardani, Ahmad; Barrett, Tim; Jones, Scott Z.; Lootens, Didier; Peltz, Max A.; Sato, Taijiro; Stutzman, Paul E.; Tanesi, Jussara; Weiss, W. Jason (Construction and Building Materials, 2014)
Limestone (calcium carbonate, CaCO3) has long been a critical component of concrete, whether as the primary raw material for cement production, a fine powder added to the binder component, or a source of fine and/or coarse aggregate. This paper focuses on the latter two of these examples, providing a multi-scale investigation of the influences of both fine limestone powder and conventional limestone aggregates on concrete performance. Fine limestone powder in the form of calcite provides a favorable surface for the nucleation and growth of calcium silicate hydrate gel at early ages, accelerating and amplifying silicate hydration, and a source of carbonate ions to participate in reactions with the aluminate phases present in the cement (and fly ash). Conversely, the aragonite polymorph of CaCO3 exhibits a different crystal (and surface) structure and therefore neither accelerates nor amplifies silicate hydration at a similar particle size/surface area. However, because these two forms of CaCO3 have similar solubilities in water, the aragonite does contribute to an enhancement in the reactivity of the aluminate phases in the investigated systems, chiefly via carboaluminate formation. In 100% ordinary Portland cement (OPC) concretes, 10% of the OPC by volume can be replaced with an equivalent volume of limestone powder, while maintaining acceptable performance. A comparison between limestone and siliceous aggregates indicates that the former often provide higher measured compressive strengths at equivalent levels of hydration, even when the two aggregate types exhibit similar elastic moduli. This suggests that the interfacial transition zone in the limestone-based concretes exhibits a higher degree of bonding, likely due to the favorable physical (texture) and chemical nature of the limestone surfaces. These observations reinforce the value of utilizing limestone to increase the performance and sustainability of 21st century concrete construction.
Keywords: Aggregates; Calcite; Calcium; Calcium carbonate; Calcium silicate; Carbonate minerals; Chemical bonds; Compressive strength; Concrete aggregates; Concretes; Crystal structure; Fly ash; Hydrates; Hydration; Particle size; Portland cement; Precipitation (chemical); Setting; Silicate minerals; Acceptable performance; Aragonite; Calcium silicate hydrate gel; Heat release; Interfacial transition zone; Ordinary Portland cement; Volume of limestone powders; Limestone

Thiophene mitigates high temperature fouling of metal surfaces in oil refining - Stephenson, Tyler; Hazelton, Mike; Kupsta, Martin; Lepore, Justin; Andreassen, Einar J.; Hoff, Anne; Newman, Bruce; Eaton, Paul; Gray, Murray; Mitlin, David (Fuel, 2014)
Inorganically driven fouling of metal heat-transfer surfaces employed in crude oil refining operations is not well understood. The object of this study is twofold: First, we systematically elucidate the time-dependent mechanism of the interrelated carbonaceous and sulfidic build up that occurs at high temperatures on a metal surface (540 °C metal temperature, 250°C oil bath temperature). Second, we demonstrate that additions of 0.5, 1.3 and 5.7 vol% thiophene (C4H4S) cause a 2×, 10×, and 20× reduction in the fouling factor after a 1400 min exposure. Analytical techniques including TEM, SEM-EDX, FIB, Auger electron spectroscopy and XRD were employed to detail the fouling phenomenology for a heated stainless steel wire immersed in atmospheric bottoms fraction crude oil, exposed for 1-1400 min. A key microstructural observation is the transformation of the wire's as-received near-surface textured austenitic grain structure into a micron scale (e.g. ∼10 μm at 1400 min) highly porous inner-sulfide/chromium oxide bilayer composite. Additionally, we observe significant localized sulfidic attack into the bulk of the metal. During testing, an iron sulfide (pyrrhotite Fe(1 - x )S) corrosion product forms almost instantaneously at the metal surface, followed by coke formation around its periphery at longer times. This temporal sequence, combined with the observation that the thicker regions of the foulant are clearly associated with detached plumes of the sulfide, leads us to argue that the sulfide is essential for promoting organic fouling. This is brought about by the sulfide's action as a potent dehydrogenation catalyst that drives the transformation of pitch to coke. We hypothesize that the tremendous fouling inhibition effect of the thiophene originates from its adsorption onto the sulfide surfaces, thereby blocking the dehydrogenation reactions.
Keywords: Fouling; Refining; Steel; High temperature; Metal surfaces; Oil; Oil refining; Organic; Corrosion

Present opto-mechanical design status of NFIRAOS - Byrnes, Peter W. G.; Atwood, Jenny; Boucher, Marc-Andre; Fitzsimmons, Joeleff; Hill, Alexis; Herriot, Glen; Spanò, Paolo; Szeto, Kei; Wevers, Ivan (SPIE - International Society for Optical Engineering. Proceedings, 2014)
This paper describes the current opto-mechanical design of NFIRAOS (Narrow Field InfraRed Adaptive Optics System) for the Thirty Meter Telescope (TMT). The preliminary design update review for NFIRAOS was successfully held in December 2011, and incremental design progress has since occurred on several fronts. The majority of NFIRAOS is housed within an insulated and cooled enclosure, and operates at -30 C to reduce background emissivity. The cold optomechanics are attached to a space-frame structure, kinematically supported by bipods that penetrate the insulated enclosure. The bipods are attached to an exo-structure at ambient temperature, which also supports up to three client science instruments and a science calibration unit.
Keywords: Optical telescopes; Structural frames; Adaptive optics systems; Incremental designs; NFIRAOS; Opto-mechanical design; Preliminary design; Space frame structure; Thirty Meter Telescope; TMT; Adaptive optics

Kinetics studies of rapid strain-promoted [3+2] cycloadditions of nitrones with bicyclo[6.1.0]nonyne - Mackenzie, Douglas A.; Pezacki, John Paul (Canadian Journal of Chemistry, 2014)
Strain-promoted alkyne-nitrone cycloaddition (SPANC) reactions represent a bioorthogonal labeling strategy that is both very rapid and at the same time efficient and selective. Nitrones provide increased reaction rates as well as greater susceptibility toward stereoelectronic modification when compared with organic azides. We find that strain-promoted cycloadditions of cyclic nitrones with bicyclo[6.1.0]nonyne react with second-order rate constants as large as 1.49 L mol-1 s-1 at 25 °C. These reactions display rate constants that are up to 37-fold greater than those of the analogous reactions of benzyl azide with bicyclo[6.1.0]nonyne. We observed that reactions of nitrones with bicyclo[6.1.0]nonyne showed a stronger dependence on substituent effect for the reaction, as evidenced by a larger Hammett Ï value, than that for biaryl-aza-cyclooctanone. We demonstrate the ability to stereoelectronically tune the reactivity of nitrones towards different cyclooctynes in SPANC reactions. This ability to introduce selectivity into different SPANC reactions through substituent provides the opportunity to perform multiple SPANC reactions in one reaction vessel and opens up potential applications in multiplex labeling.
Keywords: 1 ,3-dipolar cycloadditions; Bicyclo[6.1.0]nonyne; Click chemistry; Cycloadditions; Nitrones; Strain-promoted alkyne-nitrone cycloaddition (SPANC); Hydrocarbons; Rate constants; Cycloaddition

Polarization splitter and rotator with subwavelength grating for enhanced fabrication tolerance - Xiong, Yule; Wangüemert-Pérez, J.Gonzalo; Xu, Dan-Xia; Schmid, Jens H.; Cheben, Pavel; Ye, Winnie N. (Optics Letters, 2014)
We propose a novel method to implement a compact and fabrication-tolerant polarization splitter and rotator (PSR) on the silicon-on-insulator platform. The PSR consists of a silicon wire waveguide coupled to a subwavelength grating (SWG) waveguide in an asymmetrical directional coupler. The SWG effect allows an additional degree of design freedom to engineer the equivalent material refractive index. This is advantageously used to effectively compensate for fabrication inaccuracies in PSRs. Our simulation results show that the PSR has a low TM-to-TE polarization conversion loss of -0.13 dB (a conversion efficiency of 97%) at the wavelength of 1550 nm, and better than -0.4 dB conversion loss over the entire C-band wavelength range. Compared to the PSRs made of conventional wire waveguides, the use of SWG index engineering improves the waveguide width fabrication tolerance substantially, from ±3 nm to ±40 nm. A compact device size with a coupling length of 25 μm is achieved.
Keywords: Optical waveguides; Polarization; Refractive index; Silicon; Silicon on insulator technology; Waveguides; Fabrication tolerances; Polarization splitters; Silicon wire waveguides; Silicon-on-insulator platforms; Subwavelength grating; Waveguide widths; Wavelength ranges; Wire wave guides

Effect of tool kinematics on the drilling forces and temperature in low frequency high amplitude vibration assisted drilling - Sadek, A.; Meshreki, M.; Attia, M. H. (ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 2014)
1Defects associated with drilling of fiber reinforced polymers (FRPs) are of major economic and safety concerns for aerospace manufacturers. Delamination of layers and thermal damage of the matrix are the most critical defects associated with drilling of FRP laminates, which can be avoided by keeping the drilling forces and temperatures below some threshold levels. Vibration-assisted drilling (VAD) is an emerging drilling process that uses intermittent cutting to reduce the drilling forces and temperatures, and achieve easier chip removal compared to conventional drilling. In this paper an extensive experimental study has been conducted to provide insight into the effect of the tool kinematics corresponding to the VAD parameters (speed, feed, frequency and amplitude) on the geometry of the formed chip determined by the intersection of the trajectories of the cutting edges as well as on the drilling forces and temperature. The combinations of the VAD parameters used in this study were selected from ranges of speeds 6,000 rpm to 12,000 rpm, feeds 0.05 mm/rev to 0.15 mm/rev, frequencies 30 Hz and 60 Hz, and amplitudes 40 μm to 400 μm. The Amplitude and feed were found to have the most dominant effect on the VAD forces, while the feed and speed had the dominant effect on the VAD temperatures. The thermal performance of the VAD process was found to be enhanced by the formation of vortices in the air gap created by the separation between the tool and the machined surface, which is mainly controlled by the feed and the rotational speed of the tool.
Keywords: Fiber reinforced plastics; Kinematics; Laminates; Conventional drilling; Critical defects; Fiber reinforced polymers; High-amplitude vibrations; Intermittent cutting; Thermal Performance; Threshold levels; Vibration assisted drilling; Drilling

Real-time monitoring, diagnosis, and time-course analysis of microalgae Scenedesmus AMDD cultivation using dual excitation wavelength fluorometry - Karakach, Tobias K.; McGinn, Patrick J.; Choi, Jerome; MacQuarrie, Scott P.; Tartakovsky, Boris (Journal of Applied Phycology, 2014)
Dual excitation wavelength fluorometry was used for real-time monitoring and diagnosis of the growth of the microalgae Scenedesmus AMDD in a 300-L continuous photobioreactor (PBR). Emission spectra were acquired at 1-min intervals using excitation lights at 365 and 540 nm. Real-time dry weight estimations were achieved using linear regression with the chlorophyll peak, while protein estimations required a more complex Principal Component Regression model, which takes advantage of the full emission spectrum. The resulting regression coefficients were 0.95 and 0.80, respectively. Furthermore, the spectra were analyzed using multivariate curve resolution technique. The proposed approach for fluorescence-based, real-time measurements of key algae cultivation parameters and culture state diagnosis was successfully demonstrated in a 42-day PBR validation test.

Effects of area ratio and mean rise angle on the aerodynamics of inter-turbine ducts - Zhang, Yanfeng; Hu, Shuzhen; Mahallati, Ali; Zhang, Xue-Feng; Vlasic, Edward (Proceedings of the ASME Turbo Expo, 2014)
The present work, a continuation of a series of investigations on the aerodynamics of aggressive inter-turbine ducts (ITD), is aimed at providing detailed understanding of the flow physics and loss mechanisms in four different ITD geometries. A systematic experimental and computational study was carried out for varying duct mean rise angles and outlet-toinlet area ratio while keeping the duct length-to-inlet height ratio, Reynolds number and inlet swirl constant in all four geometries. The flow structures within the ITDs were found to be dominated by the counter-rotating vortices and boundary layer separation in both the casing and hub regions. The duct mean rise angle determined the severity of adverse pressure gradient in the casing's first bend whereas the duct area ratio mainly governed the second bend's static pressure rise. The combination of upstream wake flow and the first bend's adverse pressure gradient caused the boundary layer to separate and intensify the strength of counter-rotating vortices. At high mean rise angle, the separation became stronger at the casing's first bend and moved farther upstream. At high area ratios, a 2-D separation appeared on the casing. Pressure loss penalties increased significantly with increasing duct mean rise angle and area ratio.
Keywords: Aerodynamics; Boundary layer flow; Pressure gradient; Reynolds number; Turbines; Vortex flow; Adverse pressure gradient; Boundary-layer separation; Computational studies; Counter-rotating vortices; Pressure loss; Static pressure; Upstream wake; Ducts

Solid-state polymerization of poly(ethylene terephthalate): Effect of organoclay concentration - Dini, Maryam; Carreau, Pierre J.; Kamal, Musa R.; Ton-That, Minh-Tan; Esmaeili, Babak (Polymer Engineering and Science, 2014)
Poly(ethylene terephthalate) (PET)/Cloisite 30B (C30B) nanocomposites of different organoclay concentrations were prepared using a water-assisted extrusion process. The reduction of the molecular weight (Mw) of the PET matrix, caused by hydrolysis during water-assisted extrusion, was compensated by subsequent solid-state polymerization (SSP). Viscometry, titration, rheological, and dynamic scanning calorimetry measurements were used to analyze the samples from SSP. The weight-average molecular weight (Mw) of PET increased significantly through SSP. PET nanocomposites exhibited solid-like rheological behavior, and the complex viscosity at high frequencies was scaled with the Mw of PET. The Maron-Pierce model was used to evaluate the Mw of PET in the nanocomposites before and after SSP. It was found that the extent and the rate of the SSP reaction in nanocomposites were lower than those for the neat PETs, due to the barrier effect of clay platelets. Consequently, the SSP rate of PET increased with decreasing particle size for the neat PET and PET nanocomposites. The effect of the Mw of PET on the crystallization temperature, crystallinity, and the half-time, t1/2, of nonisothermal crystallization was also investigated. With increasing Mw of PET, t1/2 increased, whereas Tc and Xc decreased.

Introduction to special issue on post-editing - O’Brien, Sharon; Simard, Michel (Machine Translation, 2014)

Membrane order parameters for interdigitated lipid bilayers measured via polarized total-internal-reflection fluorescence microscopy - Ngo, An T.; Jakubek, Zygmunt J.; Lu, Zhengfang; Joós, Béla; Morris, Catherine E.; Johnston, Linda J. (Biochimica et Biophysica Acta - Biomembranes, 2014)
Incorporating ethanol in lipid membranes leads to changes in bilayer structure, including the formation of an interdigitated phase. We have used polarized total-internal-reflection fluorescence microscopy (pTIRFM) to measure the order parameter for Texas Red DHPE incorporated in the ethanol-induced interdigitated phase (LβI) formed from ternary lipid mixtures comprising dioleoylphosphatidylcholine, cholesterol and egg sphingomyelin or dipalmitoylphosphatidylcholine. These lipid mixtures have 3 co-existing phases in the presence of ethanol: liquid-ordered, liquid-disordered and LβI. pTIRFM using Texas Red DHPE shows a reversal in fluorescence contrast between the LβI phase and the surrounding disordered phase with changes in the polarization angle. The contrast reversal is due to changes in the orientation of the dye, and provides a rapid method to identify the LβI phase. The measured order parameters for the LβI phase are consistent with a highly ordered membrane environment, similar to a gel phase. An acyl-chain labeled BODIPY-FL-PC was also tested for pTIRFM studies of ethanol-treated bilayers; however, this probe is less useful since the order parameters of the interdigitated phase are consistent with orientations that are close to random, either due to local membrane disorder or to a mixture of extended and looping conformations in which the fluorophore is localized in the polar headgroup region of the bilayer. In summary, we demonstrate that order parameter measurements via pTIRFM using Texas Red-DHPE can rapidly identify the interdigitated phase in supported bilayers. We anticipate that this technique will aid further research in the effects of alcohols and other additives on membranes.

Ion transport and switching speed in redox-gated 3-terminal organic memory devices - Das, Bikas C.; Szeto, Bryan; James, David D.; Wu, Yiliang; McCreery, Richard L. (Journal of the Electrochemical Society, 2014)
The dynamics of redox gated organic memory devices based on dynamic doping of polythiophene were examined in detail in order to improve "write" and "erase" speed and determine ultimate performance. A 3-terminal geometry similar to a field effect transistor provided a source/gate circuit which reversibly oxidized a polythiophene polymer to cause a large increase in conductance between the source and drain electrodes. The devices were cycled for >1000 complete R/W/R/E cycles, and operated at relatively low voltage compared to commercial "flash" memory. The "write" and "erase" speeds were improved by a factor of >100 by using a spin-coated electrolyte layer and by small increases in device temperature. The influence of charging current and polaron propagation on response time were determined to be minor, with the rate limiting process being identified as the rate of conducting polaron generation. The main factor determining the W/E time was themobility of ions in the polyethylene oxide electrolyte layer, which resulted in resistance losses during the application of the S-G "write" pulse. Response time was strongly dependent on the atmosphere, with water or acetonitrile vapor significantly increasing the rate of polaron generation. The results are important for design of molecular memory devices based on dynamic doping, and indicate likely avenues for further performance improvements.
Keywords: Carrier transport; Electrolytes; Field effect transistors; Polarons; Polyethylene oxides; Charging current; Device temperature; Electrolyte layers; Molecular memory devices; Organic memory devices; Oxide electrolytes; Rate-limiting process; Source and drain electrodes; Flash memory

Measurement of the on-road turbulence environment experienced by heavy duty vehicles - McAuliffe, Brian R.; Belluz, Leanna; Belzile, Marc (SAE International Journal of Commercial Vehicles, 2014)
Terrestrial winds play an important role in affecting the aerodynamics of road vehicles. Of increasing importance is the effect of the unsteady turbulence structure of these winds and their influence on the process of optimizing aerodynamic performance to reduce fuel consumption. In an effort to predict better the aerodynamic performance of heavy-duty vehicles and various drag reduction technologies, a study was undertaken to measure the turbulent wind characteristics experienced by heavy-duty vehicles on the road.To measure the winds experienced on the road, a sport utility vehicle (SUV) was outfitted with an array of four fast-response pressure probes that could be arranged in vertical or horizontal rake configurations that provided measurements up to 4.0 m from the ground and spanning a width of 2.4 m. To characterize the influence of the proximity of the vehicle on the pressure signals of the probes, the SUV and its measurements system was calibrated in a large wind tunnel. On-road measurements of the turbulence intensities, turbulence length scales, wind spectra, and spatial correlations were performed. Eight days of testing over a two month period in late 2012 were conducted over roads in Eastern Ontario and Western Quebec, Canada. Dates and test routes were selected to provide a variety of conditions. The time-series of on-road turbulence data were segmented and classified based on differences in the terrain roughness, traffic density, and wind strength experienced during the measurements.Of the three classification categories, traffic density provided the greatest influence on the measured turbulence characteristics by modifying the strength of the high-frequency/small-scale turbulence structures in the wind. Conversely, the strength of the terrestrial winds provided a strong influence on the low-frequency/large-scale turbulence. In the near-ground region of the current study (0.5 to 4.0 m), which represents the vertical extent of typical heavy duty vehicles on the road, the turbulence length scales showed a much greater sensitivity to vertical distance than did the turbulence intensity, resulting from damping of the large-scale/low-frequency wind fluctuations near the ground.Based on the frequency of the various conditions experienced on the road, a target set of wind conditions, (intensities, length scales, spectra, correlation lengths) are recommended that differ from previously-published recommendations.
Keywords: Aerodynamic configurations; Aerodynamic drag; Aerodynamics; Roads and streets; Transportation; Vehicles; Wind; Wind tunnels; Aero-dynamic performance; Reduction technologies; Spatial correlations; Sport utility vehicles; Turbulence characteristics; Turbulence intensity; Turbulence structures; Unsteady turbulences; Turbulence

Gasification of bio-waste and biomass products through exposure to high density and low density supercritical water - Desnoo, Bob; Huang, Xiao; Ma, Weiguo; Yoo, Yeong (ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 2014)
Biomass as a sustainable and renewable energy source is starting to gain momentum, especially as more economical energy extraction methods prevail. Supercritical water biomass gasification (SCWBG) is one of the more promising methods to extract energy from biomass in a gaseous form due to its lower temperature and simpler setup. In this work, two biomass samples (considered livestock feed) and two biomass waste samples are gasified in supercritical water (SCW). To compare the gasification of the real biomass samples (beat skin and straw) to previous works on model biomass compounds, two temperature states (hence different water densities) were used during gasification. An increase in temperature and decrease in water density was found to have similar effects on real biomass compared to that of model compounds. As temperature increases and water density decreases, combustible gas yields tend to increase due to changes in reaction pathways and reaction rates. In this work an analytical comparison is also made between the four different types of biomass in terms of which produce the most combustible gases and of which will generate the most energy. As a result of this analysis beet skins produce the most methane and corn silage yields the most hydrogen. It is the two bio-waste products, however, that generated the largest higher heating values (HHV).
Keywords: Anaerobic digestion; Density of gases; Gasification; Methane; Renewable energy resources; Biomass Gasification; Energy from biomass; Higher heating value; Renewable energy source; Supercritical water; Biomass

Insulin resistance, neuroinflammation, and Alzheimer's disease - Najem, Dema; Bamji-Mirza, Michelle; Chang, Nina; Liu, Qing Yan; Zhang, Wandong (Reviews in the Neurosciences, 2014)
Alzheimer's disease (AD) is the most common form of dementia. Pathologically, it is characterized by degeneration of neurons and synapses, the deposition of extracellular plaques consisting of aggregated amyloid-â (Aâ) peptides, and intracellular neurofibrillary tangles made up of hyperphosphorylated tau protein. Recently, the spotlights have been centered on two characteristics of AD, neuroinflammation and insulin resistance. Because both of these pathways play roles in synaptic dysfunction and neurodegeneration, they become potential targets for therapeutic intervention that could impede the progression of the disease. Here, we present an overview of the traditional amyloid hypothesis, as well as emerging data on both inflammatory and impaired insulin signaling pathways in AD. It becomes evident that more than one concurrent treatment can be synergistic and various combinations should be discussed as a potential therapeutic strategy to correct the anomalies in AD. Insulin resistance, Aâ/tau pathologies, neuroinflammation, and dysregulation of central nervous system homeostasis are intertwined processes that together create the complex pathology of AD and should be considered as a whole picture.
Keywords: amyloid; insulin; tau protein; amyloid precursor protein; age; Alzheimer disease; autophosphorylation; central nervous system; degenerative disease; drug targeting; insulin resistance; nerve degeneration; nervous system inflammation; neurofibrillary tangle; neurotoxicity; risk factor; inflammation; metabolism; signal transduction; Inflammation

Testing magnetic field models for the class 0 protostar L1527 - Davidson, J. A.; Li, Z. -Y.; Hull, C. L. H.; Plambeck, R. L.; Kwon, W.; Crutcher, R. M.; Looney, L. W.; Novak, G.; Chapman, N. L.; Matthews, B. C.; Stephens, I. W.; Tobin, J. J.; et al. (The Astrophysical Journal, 2014)
For the Class 0 protostar L1527 we compare 131 polarization vectors from SCUPOL/JCMT, SHARP/CSO, and TADPOL/CARMA observations with the corresponding model polarization vectors of four ideal-MHD, nonturbulent, cloud core collapse models. These four models differ by their initial magnetic fields before collapse; two initially have aligned fields (strong and weak) and two initially have orthogonal fields (strong and weak) with respect to the rotation axis of the L1527 core. Only the initial weak orthogonal field model produces the observed circumstellar disk within L1527. This is a characteristic of nearly all ideal-MHD, nonturbulent, core collapse models. In this paper we test whether this weak orthogonal model also has the best agreement between its magnetic field structure and that inferred from the polarimetry observations of L1527. We found that this is not the case; based on the polarimetry observations, the most favored model of the four is the weak aligned model. However, this model does not produce a circumstellar disk, so our result implies that a nonturbulent, ideal-MHD global collapse model probably does not represent the core collapse that has occurred in L1527. Our study also illustrates the importance of using polarization vectors covering a large area of a cloud core to determine the initial magnetic field orientation before collapse; the inner core magnetic field structure can be highly altered by a collapse, and so measurements from this region alone can give unreliable estimates of the initial field configuration before collapse.

Polarization entangled photons from quantum dots embedded in nanowires - Huber, Tobias; Predojević, Ana; Khoshnegar, Milad; Dalacu, Dan; Poole, Philip J.; Majedi, Hamed; Weihs, Gregor (Nano Letters, 2014)
In this Letter, we present entanglement generated from a novel structure: a single InAsP quantum dot embedded in an InP nanowire. These structures can grow in a site-controlled way and exhibit high collection efficiency; we detect 0.5 million biexciton counts per second coupled into a single mode fiber with a standard commercial avalanche photo diode. If we correct for the known setup losses and detector efficiency, we get an extraction efficiency of 15(3) %. For the measured polarization entanglement, we observe a fidelity of 0.76(2) to a reference maximally entangled state as well as a concurrence of 0.57(6).
Keywords: Avalanche diodes; Light; Nanowires; Polarization; Quantum optics; Semiconductor quantum dots; Single mode fibers; Biexcitons; Detector efficiency; Extraction efficiencies; High collection efficiency; Maximally entangled state; Novel structures; Polarization entanglement; Polarization-entangled photons; Quantum entanglement

The 384-channel prototype of DM Electronics for ELT AO systems - Caputa, Kris; Atwood, Jenny; Herriot, Glen; Veran, Jean-Pierre; Spanò, Paolo; Zielinski, Adam (SPIE - International Society for Optical Engineering. Proceedings, 2014)
High order AO subsystems of the ELT require technological advancements in the Deformable Mirror (DM) construction and corresponding improvements in the drive electronics. Advanced prototyping is currently under way at NSI-Herzberg to reduce risks of deploying untried technology in the TMT AO subsystem NFIRAOS. We have developed a 96-channel output module and constructed a sub-scale DM Electronics prototype NDME384 with 384 output channels based on 4 such modules. French DM vendor Cilas has fabricated the NFIRAOS DM Breadoboard with 360 piezoelectric actuators in a 60×6 matrix, to demonstrate the DM technology to be deployed in NFIRAOS wavefront correctors. We present the results of testing our NDME384 prototype while driving the NFIRAOS DM Breadoboard.
Keywords: Actuators; Amplifiers (electronic); Deformation; Mirrors; Piezoelectric actuators; Piezoelectricity; Vision aids; Voltage regulators; Deformable mirrors; Drive electronics; ELT; High voltage amplifier; NFIRAOS; Output channels; Technological advancement; Wavefront corrector; Adaptive optics

ALMA band 10 (787-950 GHz) first astronomical fringes - Asayama, Shin’ichiro; Knee, Lewis B. G.; Calisse, Paolo G.; Colque, Juan P.; Lopez, Cristian M.; Nakos, Theodoros; Phillips, Neil M.; Plarre, Kurt H.; Radiszcz, Matias C.; Siringo, Giorgio; Whyborn, Nicholas D.; Yatagai, Hiroshi (SPIE - International Society for Optical Engineering. Proceedings, 2014)
The Atacama Large Millimeter/submillimeter Array (ALMA) Band 10 receiver covering 787 to 950 GHz is the highest frequency receiver of the ten bands envisioned for the ALMA Front End system. The Band 10 receivers have been undergoing installation and commissioning since 2012. After the Band 10 receiver tuning scripts (Josephson currents suppression, LO power optimization) and operation procedures had been developed and implemented, astronomical verification procedures (radio pointing, focus, beam squint, and end-to-end spectroscopic verification) were established in single dish mode at the ALMA Operations Support Facility (OSF; 2900 m elevation). Subsequently, the first Band 10 astronomical fringes were achieved at the Array Operations Site in October 2013 (AOS; 5000 m elevation). This is the highest frequency ever achieved by a radio interferometer and opens up a new window into submillimeter astrophysics.
Keywords: Astrophysics; Interferometers; Interferometry; Atacama Large Millimeter/sub-millimeter Array (ALMA); Frequency receivers; Power Optimization; Radio interferometers; SIS mixers; Submillimeter astrophysics; Submillimeters; Airborne telescopes

Results of the NFIRAOS RTC trade study - Véran, Jean-Pierre; Boyer, Corinne; Ellerbroek, Brent L.; Gilles, Luc; Herriot, Glen; Kerley, Daniel A.; Ljusic, Zoran; McVeigh, Eric A.; Prior, Robert; Smith, Malcolm; Wang, Lianqi (SPIE - International Society for Optical Engineering. Proceedings, 2014)
With two large deformable mirrors with a total of more than 7000 actuators that need to be driven from the measurements of six 60x60 LGS WFSs (total 1.23Mpixels) at 800Hz with a latency of less than one frame, NFIRAOS presents an interesting real-time computing challenge. This paper reports on a recent trade study to evaluate which current technology could meet this challenge, with the plan to select a baseline architecture by the beginning of NFIRAOS construction in 2014. We have evaluated a number of architectures, ranging from very specialized layouts with custom boards to more generic architectures made from commercial off-the-shelf units (CPUs with or without accelerator boards). For each architecture, we have found the most suitable algorithm, mapped it onto the hardware and evaluated the performance through benchmarking whenever possible. We have evaluated a large number of criteria, including cost, power consumption, reliability and flexibility, and proceeded with scoring each architecture based on these criteria. We have found that, with today's technology, the NFIRAOS requirements are well within reach of off-the-shelf commercial hardware running a parallel implementation of the straightforward matrix-vector multiply (MVM) algorithm for wave-front reconstruction. Even accelerators such as GPUs and Xeon Phis are no longer necessary. Indeed, we have found that the entire NFIRAOS RTC can be handled by seven 2U high-end PC-servers using 10GbE connectivity. Accelerators are only required for the off-line process of updating the matrix control matrix every ∼10s, as observing conditions change.
Keywords: Benchmarking; Computer hardware; Matrix algebra; Program processors; Real time control; Wavefronts; Base-line architecture; Commercial off the shelves; Generic architecture; Large deformable mirrors; Matrix vector multiply; Parallel implementations; Real time computing; Wave front reconstruction; Adaptive optics

Adaptive optics program at TMT - Boyer, C.; Adkins, Sean; Andersen, David R.; Atwood, Jenny; Bo, Yong; Byrnes, Peter; Caputa, Kris; Cavaco, Jeff; Ellerbroek, Brent; Gilles, Luc; Gregory, James; Herriot, Glen; et al. (SPIE - International Society for Optical Engineering. Proceedings, 2014)
The TMT first light Adaptive Optics (AO) facility consists of the Narrow Field Infra-Red AO System (NFIRAOS) and the associated Laser Guide Star Facility (LGSF). NFIRAOS is a 60 × 60 laser guide star (LGS) multi-conjugate AO (MCAO) system, which provides uniform, diffraction-limited performance in the J, H, and K bands over 17-30 arc sec diameter fields with 50 per cent sky coverage at the galactic pole, as required to support the TMT science cases. NFIRAOS includes two deformable mirrors, six laser guide star wavefront sensors, and three low-order, infrared, natural guide star wavefront sensors within each client instrument. The first light LGSF system includes six sodium lasers required to generate the NFIRAOS laser guide stars. In this paper, we will provide an update on the progress in designing, modeling and validating the TMT first light AO systems and their components over the last two years. This will include pre-final design and prototyping activities for NFIRAOS, preliminary design and prototyping activities for the LGSF, design and prototyping for the deformable mirrors, fabrication and tests for the visible detectors, benchmarking and comparison of different algorithms and processing architecture for the Real Time Controller (RTC) and development and tests of prototype candidate lasers. Comprehensive and detailed AO modeling is continuing to support the design and development of the first light AO facility. Main modeling topics studied during the last two years include further studies in the area of wavefront error budget, sky coverage, high precision astrometry for the galactic center and other observations, high contrast imaging with NFIRAOS and its first light instruments, Point Spread Function (PSF) reconstruction for LGS MCAO, LGS photon return and sophisticated low order mode temporal filtering.
Keywords: Astronomy; Deformation; Laser mirrors; Light; Mirrors; Optical testing; Optical transfer function; Stars; Wavefronts; Design and Development; Diffraction limited; Extremely Large Telescopes; High contrast imaging; Point spread function reconstruction; Processing architectures; Real time controllers; Wave front sensors; Adaptive optics

Gemini Planet Imager observational calibrations I: Overview of the GPI data reduction pipeline - Perrin, Marshall D.; Maire, Jerome; Ingraham, Patrick; Savransky, Dmitry; Millar-Blanchaer, Max; Wolff, Schuyler G.; Ruffio, Jean-Baptiste; Wang, Jason J.; Draper, Zachary H.; Sadakuni, Naru; Marois, Christian; Rajan, Abhijith; et al. (SPIE - International Society for Optical Engineering. Proceedings, 2014)
The Gemini Planet Imager (GPI) has as its science instrument an infrared integral field spectrograph/polarimeter (IFS). Integral field spectrographs are scientificially powerful but require sophisticated data reduction systems. For GPI to achieve its scientific goals of exoplanet and disk characterization, IFS data must be reconstructed into high quality astrometrically and photometrically accurate datacubes in both spectral and polarization modes, via flexible software that is usable by the broad Gemini community. The data reduction pipeline developed by the GPI instrument team to meet these needs is now publicly available following GPI's commissioning. This paper, the first of a series, provides a broad overview of GPI data reduction, summarizes key steps, and presents the overall software framework and implementation. Subsequent papers describe in more detail the algorithms necessary for calibrating GPI data. The GPI data reduction pipeline is open source, available from planetimager.org, and will continue to be enhanced throughout the life of the instrument. It implements an extensive suite of task primitives that can be assembled into reduction recipes to produce calibrated datasets ready for scientific analysis. Angular, spectral, and polarimetric differential imaging are supported. Graphical tools automate the production and editing of recipes, an integrated calibration database manages reference files, and an interactive data viewer customized for high contrast imaging allows for exploration and manipulation of data.
Keywords: Astronomy; Calibration; Data handling; Extrasolar planets; Open source software; Pipelines; Polarimeters; Spectrographs; Exo-planets; High contrast imaging; Integral field spectrograph; Integral Field Spectroscopy; Polarization modes; Reduction systems; Scientific analysis; Data reduction

Dynamic mechanical thermo-analysis of Portland cement paste hydrated for 45 years - Pourbeik, P.; Beaudoin, J. J.; Alizadeh, R.; Raki, L. (Materials and Structures, 2014)
The effect of prolonged hydration of Portland cement paste on engineering behavior was investigated using dynamic mechanical thermo-analysis (DMTA) methods. Specimens ranged in age from 3 days to 45 years. Compacts of hydrated cement powders and normally hydrated paste specimens were tested. Age dependent nanostructural characteristics of C–S–H were shown to influence the mechanical response of cement paste. Evidence was provided to support the use of compacts as structural models for hydrated cement paste. Details of ageing effects on the DMTA parameters (storage modulus and internal friction) as a function of temperature and porosity are reported.
Keywords: Dynamics; Hydration; Porosity; Portland cement; Powders; Ageing effects; Cement paste; Dynamic mechanical; Hydrated cement pastes; Mechanical response; Nanostructural characteristics; Portland cement paste; Structural models; Dynamic mechanical analysis

Guest-induced symmetry lowering of an ionic clathrate material for carbon capture - Muromachi, S.; Udachin, K. A.; Shin, K.; Alavi, S.; Moudrakovski, I. L.; Ohmura, R.; Ripmeester, J. A. (Chemical Communications, 2014)
We report a new lattice structure of the ionic clathrate hydrate of tetra-n-butylammonium bromide induced by guest CO2 molecules, which is found to provide high CO2 storage capacity. The structure was characterized by a set of methods, including single crystal X-ray diffraction, NMR, and MD simulations.
Keywords: carbon; ionic clathrate hydrate; tetrabutylammonium; unclassified drug; chemical structure; crystal structure; encapsulation; molecular docking; nuclear magnetic resonance; proton nuclear magnetic resonance; X ray diffraction

Speech-based interaction: Myths, challenges, and opportunities - Munteanu, Cosmin; Penn, Gerald (Conference on Human Factors in Computing Systems - Proceedings, 2014)
HCI research has for long been dedicated to better and more naturally facilitating information transfer between humans and machines. Unfortunately, humans' most natural form of communication, speech, is also one of the most difficult modalities to be understood by machines - despite, and perhaps, because it is the highest-bandwidth communication channel we possess. While significant research efforts, from engineering, to linguistic, and to cognitive sciences, have been spent on improving machines' ability to understand speech, the CHI community has been relatively timid in embracing this modality as a central focus of research. This can be attributed in part to the relatively discouraging levels of accuracy in understanding speech, in contrast with often-unfounded claims of success from industry, but also to the intrinsic difficulty of designing and especially evaluating speech and natural language interfaces. As such, the development of interactive speech-based systems is mostly driven by engineering efforts to improve such systems with respect to largely arbitrary performance metrics, often void of any user-centered design principles or consideration for usability or usefulness. The goal of this course is to inform the CHI community of the current state of speech and natural language research, to dispel some of the myths surrounding speech-based interaction, as well as to provide an opportunity for researchers and practitioners to learn more about how speech recognition and speech synthesis work, what are their limitations, and how they could be used to enhance current interaction paradigms. Through this, we hope that HCI researchers and practitioners will learn how to combine recent advances in speech processing with user-centred principles in designing more usable and useful speech-based interactive systems.
Keywords: Engineering research; Human computer interaction; Human engineering; Natural language processing systems; Speech processing; Speech recognition; Speech synthesis; Telecommunication systems; User interfaces; Automatic speech recognition; Current interactions; Information transfers; NAtural language processing; Natural user interfaces; Speech and natural language interface; Speech interaction; User centered designs; Speech communication

Lactone-bound structures of cyclohexanone monooxygenase provide insight into the stereochemistry of catalysis - Yachnin, Brahm J.; McEvoy, Michelle B.; Maccuish, Roderick J. D.; Morley, Krista L.; Lau, Peter C. K.; Berghuis, Albert M. (ACS Chemical Biology, 2014)
The Baeyer-Villiger monooxygenases (BVMOs) are microbial enzymes that catalyze the synthetically useful Baeyer-Villiger oxidation reaction. The available BVMO crystal structures all lack a substrate or product bound in a position that would determine the substrate specificity and stereospecificity of the enzyme. Here, we report two crystal structures of cyclohexanone monooxygenase (CHMO) with its product, ε-caprolactone, bound: the CHMOTight and CHMOLoose structures. The CHMOTight structure represents the enzyme state in which substrate acceptance and stereospecificity is determined, providing a foundation for engineering BVMOs with altered substrate spectra and/or stereospecificity. The CHMOLoose structure is the first structure where the product is solvent accessible. This structure represents the enzyme state upon binding and release of the substrate and product. In addition, the role of the invariant Arg329 in chaperoning the substrate/product during the catalytic cycle is highlighted. Overall, these data provide a structural framework for the engineering of BVMOs with altered substrate spectra and/or stereospecificity.
Keywords: cyclohexanone; enzyme; lactone; microbial enzyme; polycaprolactone; unspecific monooxygenase; binding site; catalysis; conformational transition; crystal structure; enzyme structure; oxidation; protein conformation; protein cross linking; stereochemistry; stereospecificity

Broadband two-mode multiplexer with taper-etched directional coupler on SOI platform - Xiong, Yule; Xu, Dan-Xia; Schmid, Jens H.; Cheben, Pavel; Janz, Siegfried; Ye, Winnie N. (IEEE International Conference on Group IV Photonics GFP, 2014)
We propose an original two-mode (TE0/TE1) division multiplexer using a taper-etched directional coupler. The multiplexer has a low insertion loss of -0.1 dB within C-band with a minimum loss of -0.05 dB, a modal crosstalk below -40 dB and a robust fabrication tolerance (>100 nm).

Tribological properties of boride based thermal diffusion coatings - Medvedovski, E.; Jiang, J. R.; Robertson, M. (Advances in Applied Ceramics, 2014)
Engineering components, e.g. tubing systems for the down-hole applications in the oil and gas industry (in particular, sucker rod pumps, progressing cavity pumps and some other components of the artificial lifting systems), as well as numerous valves and seats, bearings, gears and plungers, require protection against friction and sliding abrasion service conditions. The hard boride based coatings on steels and alloys obtained through the thermal diffusion process have a high potential for these severe application conditions over many other types of coatings as they can be obtained on the entire working surfaces of large size and complex shape products. Intensive tribological studies of the iron boride based coatings on carbon steel obtained at Endurance Technologies Inc. have been conducted using the Cameron-Plint testing unit (reciprocating sliding of the metallic rod under the load over a flat surface of the coated samples). The friction wear loss, friction coefficient and structural changes of the coatings have been studied in dry and lubricating (water-oil) friction conditions, which simulate actual application conditions. It was demonstrated that the obtained boride coatings have the friction loss significantly smaller than untreated steel (e.g. ∼10-30 times in the dry conditions and at least 5 times in the lubricating conditions) with no peeling and flaking-off. The friction coefficients of the boride coatings are steady over the test duration. The influence of the thickness on the boride coatings performance is demonstrated. The encouraging results are explained by the specific coating structure of the hard coating obtained through the thermal diffusion process and the thin 'tribofilm' formed during a friction mode.
Keywords: Friction; Thermal diffusion; Coefficient of frictions; Iron boride; Tribological properties; Coatings

Globular cluster systems in brightest cluster galaxies: A near-universal luminosity function? - Harris, William E.; Morningstar, Warren; Gnedin, Oleg Y.; O'Halloran, Heather; Blakeslee, John P.; Whitmore, Bradley C.; Côté, Patrick; Geisler, Douglas; Peng, Eric W.; Bailin, Jeremy; Rothberg, Barry; Cockcroft, Robert; et al. (The Astrophysical Journal, 2014)
We present the first results from our Hubble Space Telescope brightest cluster galaxy (BCG) survey of seven central supergiant cluster galaxies and their globular cluster (GC) systems. We measure a total of 48,000 GCs in all seven galaxies, representing the largest single GC database. We find that a log-normal shape accurately matches the observed the luminosity function (LF) of the GCs down to the globular cluster luminosity function turnover point, which is near our photometric limit. In addition, the LF has a virtually identical shape in all seven galaxies. Our data underscore the similarity in the formation mechanism of massive star clusters in diverse galactic environments. At the highest luminosities (L ≳ 107L⊙), we find small numbers of "superluminous" objects in five of the galaxies; their luminosity and color ranges are at least partly consistent with those of ultra-compact dwarfs. Last, we find preliminary evidence that in the outer halo (R ≳ 20 kpc), the LF turnover point shows a weak dependence on projected distance, scaling as L0 ∼ R-0.2, while the LF dispersion remains nearly constant.

The wetting behavior of TiO2 nanotube arrays with perfluorinated surface functionalization - Farsinezhad, Samira; Waghmare, Prashant; Wiltshire, Benjamin D.; Amiri, Saeid; Mitra, Sushanta K.; Shankar, Karthik (ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 2014)
A facile electrochemical anodization method was used for producing hierarchically textured surfaces based on TiO2 nanotubes in two different configurations. It was found that perfluoro-functionalized TiO2 nanotubes exhibit high static contact angles for a variety of liquids such as apolar, polar aprotic and polar protic solvents. Wenzel and Cassie-Baxter theories were applied for theoretical contact angle calculations for the present study. By using Cassie theories, it is shown that a drop of polar liquid was in a fakir or Cassie-Baxter (CB) state on perfluoro-functionalized nanotube surfaces. The fakir state prevents spreading of the liquid on the surface. On the other hand, the wetting of non-polar liquids such as hexane is characterized by either Wenzel states or transition states characterized by partial imbibition that lie in between the CB and Wenzel states.
Keywords: Contact angle; Liquids; Titanium dioxide; Wetting; Electro-chemical anodization; Functionalized nanotubes; Functionalized tio; Nonpolar liquids; Static contact angle; Surface Functionalization; Transition state; Wetting behavior; Nanotubes

Agrobacterium-mediated transformation of tarwi (Lupinus mutabilis Sweet), a potential platform for the production of plant-made proteins - Polowick, Patricia L.; Loukanina, Natalia N.; Doshi, Ketan M. (In Vitro Cellular & Developmental Biology - Plant, 2014)
A robust, reproducible method of Agrobacterium-mediated transformation was developed for Lupinus mutabilis Sweet (tarwi), a large-seeded Andean legume. Initially, a regeneration and transformation protocol was developed using a plasmid which contained a bifunctional fusion gene conferring both β-glucuronidase (gus) and neomycin phosphotransferase activities, under the control of a constitutive 35S35SAMV promoter. The tissue explants consisted of longitudinal slices from embryonic axes of imbibed, mature seed. Using a series of tissue culture media for cocultivation, shoot initiation, shoot elongation, and rooting, kanamycin-resistant transgenic plants were recovered from approximately 1% of the explants. This transformation protocol was further used with a construct that contained the human adenosine deaminase (hADA) gene under the control of a legumin seed-specific promoter, also with a kanamycin resistance cassette for chemical selection. Changes made during the course of this study, which included adjustments to the antibiotic concentration during the shoot elongation and rooting phases plus the incorporation of techniques to improve ventilation in the tissue culture system, resulted in major improvements in shoot quality and, most significantly, rooting. The outcome was an increased frequency of transgenic plant recovery (7.4%), with a low (9.6%) rate of plants that escaped selection. The inheritance of the hADA gene was documented and showed the expected Mendelian segregation pattern. The produced hADA protein was a fully functional enzyme and localized only in the seed, as expected. Thus, this legume species is an excellent candidate for a nonfood plant host platform for the production of plant-made proteins.

Spatially resolved imaging of the two-component η crv debris disk with herschel - Duchêne, G.; Arriaga, P.; Wyatt, M.; Kennedy, G.; Sibthorpe, B.; Lisse, C.; Holland, W.; Wisniewski, J.; Clampin, M.; Kalas, P.; Pinte, C.; Wilner, D.; et al. (The Astrophysical Journal, 2014)
We present far-infrared and submillimeter images of the η Crv debris disk system obtained with Herschel and SCUBA-2, as well as Hubble Space Telescope visible and near-infrared coronagraphic images. In the 70 μm Herschel image, we clearly separate the thermal emission from the warm and cold belts in the system, find no evidence for a putative dust population located between them, and precisely determine the geometry of the outer belt. We also find marginal evidence for azimuthal asymmetries and a global offset of the outer debris ring relative to the central star. Finally, we place stringent upper limits on the scattered light surface brightness of the outer ring. Using radiative transfer modeling, we find that it is impossible to account for all observed properties of the system under the assumption that both rings contain dust populations with the same properties. While the outer belt is in reasonable agreement with the expectations of steady-state collisional cascade models, albeit with a minimum grain size that is four times larger than the blow-out size, the inner belt appears to contain copious amounts of small dust grains, possibly below the blow-out size. This suggests that the inner belt cannot result from a simple transport of grains from the outer belt and rather supports a more violent phenomenon as its origin. We also find that the emission from the inner belt has not declined over three decades, a much longer timescale than its dynamical timescale, which indicates that the belt is efficiently replenished.