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An augmented reality sign-reading assistant for users with reduced vision
No full textPeople typically rely heavily on visual information when finding their way to unfamiliar locations. For individuals with reduced vision, there are a variety of navigational tools available to assist with this task if needed. However, for wayfinding in unfamiliar indoor environments the applicability of existing tools is limited. One potential approach to assist with this task is to enhance visual information about the location and content of existing signage in the environment. With this aim, we developed a prototype software application, which runs on a consumer head-mounted augmented reality (AR) device, to assist visually impaired users with sign-reading. The sign-reading assistant identifies real-world text (e.g., signs and room numbers) on command, highlights the text location, converts it to high contrast AR lettering, and optionally reads the content aloud via text-to-speech. We assessed the usability of this application in a behavioral experiment. Participants with simulated visual impairment were asked to locate a particular office within a hallway, either with or without AR assistance (referred to as the AR group and control group, respectively). Subjective assessments indicated that participants in the AR group found the application helpful for this task, and an analysis of walking paths indicated that these participants took more direct routes compared to the control group. However, participants in the AR group also walked more slowly and took more time to complete the task than the control group. The results point to several specific future goals for usability and system performance in AR-based assistive tools.Peer reviewed: YesNRC publication: Ye
Characterization of the protein fraction of the extracellular polymeric substances of three anaerobic granular sludges
No full textExtracellular polymeric substances (EPS) play major roles in the efficacy of biofilms such as anaerobic granules, ranging from structural stability to more specific functions. The EPS of three granular anaerobic sludges of different origins were studied and compared. Particularly, the peptides from the protein fraction were identified by mass spectrometry. Desulfoglaeba and Treponema bacterial genera and Methanosaeta and Methanobacterium archaeal genera were prominent in all three sludges. Methanosaeta concilii proteins were the most represented in EPS of all three sludges studied. Principally, four proteins found in the three sludges, the S-layer protein, the CO-methylating acetyl-CoA synthase, an ABC transporter substrate-binding protein and the methyl-coenzyme M reductase, were expressed by Methanosaeta concilii. Mainly catabolic enzymes were found from the 45 proteins identified in the protein fraction of EPS. This suggests that EPS may have a role in allowing extracellular catabolic reactions.Peer reviewed: YesNRC publication: Ye
Reaping the benefits of machine learning pattern recognition in nanophotonic component design
No full textIntegrated nanophotonic component design processes are often constrained by computational resources. Advances in simulation and optimization tools have allowed more efficient exploration of larger design spaces. These developments reduce the time-consuming and intuition-limited effort of encoding physical insights into the design structure. However, we argue that efficient optimization is only part of the solution to tackle larger multi-parameter design spaces. Finding patterns in such a space can be more valuable than identifying the individual optima alone. This is particularly true when transitioning from simulation to real device fabrication, where considerations such as tolerance to fabrication imperfections, bandwidth, etc. take an important role but are ignored at the optimization stage. The elucidation of patterns in a complex design space enables efficient identification of designs addressing these additional considerations. As an example, in this presentation we demonstrate how limited data collected from the optimization process of a multisegment vertical grating coupler can be used to identify such patterns through the application of machine learning techniques. The identified patterns, some more interpretable than others, can be used in multiple ways: from speeding up the remaining optimization process itself to gaining insight into the properties of an interesting subset of designs. Together those insights offer a significantly clearer picture of the design space and form the basis for making much more informed decisions on the final designs to be fabricated.Peer reviewed: YesNRC publication: Ye
Model of dehydration and assessment of moisture content on onion using EIS
No full textOnion is perishable and thereby subject to drying during unrefrigerated storage. Its moisture content is important to ensure optimum quality in storage. To track and analyze the dynamics of natural dehydration in onion and also to assess its moisture content, noninvasive and nondestructive methods are preferred. One of them is known as electrical impedance spectroscopy (or EIS in short). In the first phase of our experiment, we have used EIS, where we apply alternating current with multiple frequency to the object (onion in this case) and generate impedance spectrum which is used to characterize the object. We then develop an equivalent electrical circuit representing onion characteristics using a computer assisted optimization technique that allows us to monitor the response of onion undergoing natural drying for a duration of 3 weeks. The developed electrical model shows better congruence with the impedance data measured experimentally when compared to other conventional models for plant tissue with a mean absolute error of 0.42% and root mean squared error of 0.55%. In the second phase of our experiment, we attempted to find a correlation between the previous impedance data and the actual moisture content of the onions under test (measured by weighing) and developed a mathematical model. This model will provide an alternative tool for assessing the moisture content of onion nondestructively. Our model shows excellent correlation with the ground truth data with a deterministic coefficient of 0.9767, root mean square error of 0.02976 and sum of squared error of 0.01329. Therefore, our two models will offer plant scientists the ability to study the physiological status of onion both qualitatively and quantitatively.Peer reviewed: YesNRC publication: Ye
Nitrogen- and phosphorus-starved Triticum aestivum show distinct belowground microbiome profiles
No full textMany plants have natural partnerships with microbes that can boost their nitrogen (N) and/or phosphorus (P) acquisition. To assess whether wheat may have undiscovered associations of these types, we tested if N/P-starved Triticum aestivum show microbiome profiles that are simultaneously different from those of N/P-amended plants and those of their own bulk soils. The bacterial and fungal communities of root, rhizosphere, and bulk soil samples from the Historical Dryland Plots (Lethbridge, Canada), which hold T. aestivum that is grown both under N/P fertilization and in conditions of extreme N/P-starvation, were taxonomically described and compared (bacterial 16S rRNA genes and fungal Internal Transcribed Spacers\u2014ITS). As the list may include novel N- and/or P-providing wheat partners, we then identified all the operational taxonomic units (OTUs) that were proportionally enriched in one or more of the nutrient starvation- and plant-specific communities. These analyses revealed: a) distinct N-starvation root and rhizosphere bacterial communities that were proportionally enriched, among others, in OTUs belonging to families Enterobacteriaceae, Chitinophagaceae, Comamonadaceae, Caulobacteraceae, Cytophagaceae, Streptomycetaceae, b) distinct N-starvation root fungal communities that were proportionally enriched in OTUs belonging to taxa Lulworthia, Sordariomycetes, Apodus, Conocybe, Ascomycota, Crocicreas, c) a distinct P-starvation rhizosphere bacterial community that was proportionally enriched in an OTU belonging to genus Agrobacterium, and d) a distinct P-starvation root fungal community that was proportionally enriched in OTUs belonging to genera Parastagonospora and Phaeosphaeriopsis. Our study might have exposed wheat-microbe connections that can form the basis of novel complementary yield-boosting tools.Peer reviewed: YesNRC publication: Ye
Porous nanophotonic optomechanical beams for enhanced mass adsorption
No full textWe have developed a porous silicon nanocantilever for a nano-optomechanical system (NOMS) with a universal sensing surface for enhanced sensitivity. Using electron beam lithography, we selectively applied a V2O5/HF stain etch to the mechanical elements while protecting the silicon-on-insulator photonic ring resonators. This simple, rapid, and electrodeless approach generates tunable device porosity simultaneously with the mechanical release step. By controlling the porous etchant concentration and etch time, the porous etch depth, resonant frequency, and the adsorption surface area could be precisely manipulated. Using this control, cantilever sensors ranging from nonporous to fully porous were fabricated and tested as gas-phase mass sensors of volatile organic compounds coming from a gas chromatography stream. The fully porous cantilever produced a dramatic 10-fold increase in sensing signal and a 6-fold improvement in limit of detection (LOD) compared to an otherwise identical nonporous cantilever. This signal improvement could be separated into mass responsivity increase and adsorption increase components. Allan deviation measurements indicate that a further 4-fold improvement in LOD could be expected upon speeding up characteristic peak response time from 1 s to 50 ms. These results show promise for performance enhancement in nanomechanical sensors for applications in gas sensing, gas chromatography, and mass spectrometry.Peer reviewed: YesNRC publication: Ye
A method to conduct longitudinal studies on indoor environmental quality and perceived occupant comfort
No full textBuildings with transient occupancy such as malls and sport facilities pose a particular challenge for evaluating the effect of indoor environmental quality (IEQ) on occupant comfort due to 1) the difficulties in communicating with their occupants and 2) significant daily variations in their occupancy profiles. To this end, this research presents a method to conduct longitudinal studies in which IEQ and occupant comfort are continuously and simultaneously evaluated. The proposed method relies on using electronic occupant survey devices to enable data collection on a large scale and over longer durations. To validate the proposed method, it was implemented in a gymnastics center in eastern Ontario, Canada between September 2017 and February 2018. Over 1000 survey responses were collected and analyzed relative to prevailing IEQ conditions in the hour preceding each survey response. Analyses showed a stronger correlation between measured temperature and occupants' thermal comfort in comparison to the relationship between carbon dioxide concentrations and occupants\u2019 perception of the indoor air quality. The case study demonstrated the feasibility of the proposed research method which can be replicated on a wider scale in different building types, especially those with transient occupancy, to further investigate the effect of IEQ on occupant comfort.Peer reviewed: YesNRC publication: Ye
A practical ELISA for Azaspiracids in shellfish via development of a new plate-coating antigen
No full textAzaspiracids (AZAs) are a group of biotoxins that appear periodically in shellfish and can cause food poisoning in humans. Current methods for quantifying the regulated AZAs are restricted to LC-MS but are not well suited to detecting novel and unregulated AZAs. An ELISA method for total AZAs in shellfish was reported recently, but unfortunately, it used relatively large amounts of the AZA-1-containing plate-coating conjugate, consuming significant amounts of pure AZA-1 per assay. Therefore, a new plate-coater, OVA\u2013cdiAZA1 was produced, resulting in an ELISA with a working range of 0.30\u20134.1 ng/mL and a limit of quantification of 37 \u3bcg/kg for AZA-1 in shellfish. This ELISA was nearly twice as sensitive as the previous ELISA while using 5-fold less plate-coater. The new ELISA displayed broad cross-reactivity toward AZAs, detecting all available quantitative AZA reference materials as well as the precursors to AZA-3 and AZA-6, and results from shellfish analyzed with the new ELISA showed excellent correlation (R2 = 0.99) with total AZA-1\u201310 by LC-MS. The results suggest that the new ELISA is suitable for screening samples for total AZAs, even in cases where novel AZAs are present and regulated AZAs are absent, such as was reported recently from Puget Sound and the Bay of Naples.Peer reviewed: YesNRC publication: Ye
Comparison of xenon triple point realizations
No full textIt is widely recognized that the Mercury triple point (MTP) being situated very close to the Water triple point (WTP) constitutes a weakness in the International Temperature Scale of 1990 (ITS-90), in addition to safety concerns related to the use and transportation of Mercury. As such, a substitution for a safer, high-quality fixed point about half way between the Argon and Water triple points would be highly desirable. Now, a direct comparison is described of a Xenon cell filled in 2005 by the National Research Council Canada (NRC) and a more recently produced cell of the Istituto Nazionale di Ricerca Metrologica (INRIM). The present paper discusses the INRiM 2017 measurements on both the INRiM and NRC cells, with a follow-up measurement at NRC, and presents the difference between the two cells, (0.17\u2009\u2009\ub1\u2009\u20090.08) mK with the uncertainties of each cell's realization of the Xenon triple point (XeTP), 0.11 mK for the INRiM cell and 0.07 mK for the NRC cell (k\u2009\u2009=\u2009\u20091). In addition, the effect of substituting Mercury with Xenon on Type 1 non-uniqueness ('SRI', subrange inconsistency), Type 3 non-uniqueness ('NU3', cSPRT variability) and propagation of fixed point realization uncertainty is shown and discussed.Peer reviewed: YesNRC publication: Ye
Galvanic corrosion risk of using galvanized A325 bolts in corrosion-resistant steel bridges
No full textThis experimental study was the first to evaluate the galvanic corrosion risk of using galvanized ASTM A325 Type I bolts with ASTM A1010 steel girders in the construction of A1010 steel bridges. The emerging construction of A1010 steel bridges is intended to extend the service life of bridges and reduce the need for maintenance under atmospheric corrosion attack, particularly in regions subject to severe saline exposure. However, combining high-corrosion-resistant A1010 steel with connection bolts that have a lower corrosion-resistance rating can lead to galvanic corrosion that accelerates the metal dissolution of bolts after installation and while in service. The results of this study indicate that under light saline exposure, the galvanic corrosion rate of galvanized ASTM A325 bolts used with A1010 steel was similar to the corrosion rate of A325 bolts used with ASTM A588 weathering steel. Under heavy saline exposure, however, the galvanic corrosion rate of A325 bolts was significantly higher when used with A1010 steel than when used with A588 weathering steel. Reducing the galvanic corrosion rate can be achieved by painting the joints of the steel girders, thereby reducing the cathode-to-anode area ratio. The results of this study suggest that the corrosion compatibility of the bolt and steel materials must be considered when designing corrosion-resistant A1010 steel bridges, and that the compatibility must be confirmed with an experimental validation.Peer reviewed: YesNRC publication: Ye