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Peter M. Millman Astrophysics Division finding aid
No full textPeter Mackenzie Millman was employed at the NRC from 1955 to 1986. He continued to work at a professional capacity until 1989, and dies in 1990. He was an astrophysicist and worked in the Radio and Electrical Engineering Division, Upper Atmosphere Research Division and the Herzberg Institute of Astrophysics during his tenure at the NRC. His main are of research was that of comets, meteors, meteoroids and meteorites.The "Peter M. Millman Astrophysics Division" collection is stored in the NRC Archives.La collection "Peter M. Millman Astrophysics Division" est conserv\ue9e dans les Archives du CNRC.Peer reviewed: NoNRC publication: Ye
Addendum to RR-335: sound transmission through Nail-Laminated Timber (NLT) assemblies
No full textThis report is published as an addendum to NRC Research Report RR-335 \u201cApparent Sound Insulation in Cross-Laminated Timber Buildings." It is intended that this addendum will be merged with RR-335 in the future as a report for predicting the sound insulation in buildings using mass-timber constructions including NLT assemblies. This report presents the results from experimental studies of airborne sound transmission through assemblies of nail-laminated timber (NLT) with various linings. To put the data presented in this report in the proper context, this report begins with a brief explanation of calculation procedures to predict the apparent sound transmission class (ASTC) between adjacent spaces in a building whose structure is a combination of mass-timber assemblies such as nail-laminated timber (NLT) or cross-laminated timber (CLT) panels.Peer reviewed: NoNRC publication: Ye
Real-time monitoring for structural health, public safety, and risk management of mine tailings dams
No full textPublic awareness of tailings dam failures is increasing in the wake of incidents in Canada and abroad. The present work establishes the current state of practice in mine tailings dam monitoring and provides a summary of the current technical and operational gaps identified through industry and stakeholder engagement. These gaps may be addressed with currently available technologies supplied by commercial instrumentation manufacturers; however, the assumed costs and lack of regulatory demand may serve as barriers to adoption. An integrated approach and diverse suite of technologies is needed to address issues of dam stability, worker and public safety, and environmental protection. Technological applications and limitations are described and design requirements are proposed for an integrated, real-time monitoring system. Socio-economic impacts and loss reduction benefits are considered and the need for industry and regulator participation is emphasized.La sensibilisation du grand public aux ruptures de digues \ue0 st\ue9riles augmente dans la foul\ue9e d\u2019incidents au Canada et \ue0 l\u2019\ue9tranger. L\u2019article d\ue9crit l\u2019\ue9tat actuel des pratiques de surveillance des digues \ue0 st\ue9riles et pr\ue9sente un r\ue9sum\ue9 des lacunes techniques et op\ue9rationnelles actuelles cern\ue9es en consultation avec l\u2019industrie et les parties prenantes. Si ces lacunes peuvent \ueatre combl\ue9es avec les technologies actuellement fournies par des fabricants d\u2019instruments commerciaux, les co\ufbts pr\ue9sum\ue9s et l\u2019absence d\u2019exigences r\ue9glementaires pourraient constituer des obstacles \ue0 l\u2019adoption de ces technologies. Une approche int\ue9gr\ue9e et un ensemble diversifi\ue9 de technologies sont n\ue9cessaires pour r\ue9gler les probl\ue8mes associ\ue9s \ue0 la stabilit\ue9 des digues, \ue0 la s\ue9curit\ue9 des travailleurs et du public et \ue0 la protection de l\u2019environnement. Des applications techniques et leurs limites sont d\ue9crites, et des exigences de conception sont propos\ue9es pour un syst\ue8me int\ue9gr\ue9 de surveillance en temps r\ue9el. Les impacts socio\ue9conomiques et les avantages d\ue9coulant de la r\ue9duction des pertes sont abord\ue9s, tout en insistant sur l\u2019importance de la participation de l\u2019industrie et des organismes de r\ue9glementation.Peer reviewed: YesNRC publication: Ye
Stereochemical definition of the natural product (6R,10R,13R, 14R,16R,17R,19S,20S,21R,24S,25S,28S,30S,32R,33R,34R,36S,37S,39R)\u2010azaspiracid\u20103 by total synthesis and comparative analyses
No full textThe previously accepted structure of the marine toxin azaspiracid\u20103 is revised based upon an original convergent and stereoselective total synthesis of the natural product. The development of a structural revision hypothesis, its testing, and corroboration are reported. Synthetic (6R,10R,13R,14R,16R,17R,19S,20S,21R,24S,25S,28S,30S,32R, 33R,34R,36S,37S,39R)\u2010azaspiracid\u20103 chromatographically and spectroscopically matched naturally occurring azaspiracid\u20103, whereas the previously assigned 20R epimer did not.Peer reviewed: YesNRC publication: Ye
Steroids limit myocardial edema during Ex\ua0vivo perfusion of hearts donated after circulatory death
No full textBackground: Normothermic ex vivo heart perfusion (EVHP) has been shown to improve the preservation of hearts donated after circulatory arrest and to facilitate clinical successful transplantation. Steroids are added to the perfusate solution in current clinical EVHP protocols; however, the impact of this approach on donor heart preservation has not been previously investigated. We sought to determine the impact of steroids on the inflammatory response and development of myocardial edema during EVHP. Methods: Thirteen pigs were anesthetized, mechanical ventilation was discontinued, and a hypoxemic cardiac arrest ensued. A 15-minute warm-ischemic standoff period was observed, and then hearts were resuscitated with a cardioplegic solution. Donor hearts were then perfused ex vivo in a normothermic beating state for 6 hours with 500 mg of methylprednisolone (steroid: n = 5) or without (control: n = 8). Results: The addition of steroids to the perfusate solution reduced the generation of proinflammatory cytokines (interleukin-6, -8, -1\u3b2, and tumor necrosis factor-\u3b1) and the development of myocardial edema during EVHP (percentage of weight gain: control = 26% \ub1 7% versus steroid = 16% \ub1 10%, p = 0.049). Electron microscopy suggested less endothelial cell edema in the steroid group (injury score: control = 1.8 \ub1 0.2 versus steroid = 1.2 \ub1 0.2, p = 0.06), whereas perfusate troponin-I (control = 11.9 \ub1 1.9 ng/mL versus steroid = 9.5 \ub1 2.4 ng/mL, p = 0.448) and myocardial function were comparable between the groups. Conclusions: The addition of methylprednisolone to the perfusion solution minimizes the generation of proinflammatory cytokines and development of myocardial edema during normothermic ex vivo perfusion of hearts donated after circulatory arrest.Peer reviewed: YesNRC publication: Ye
Analysis of the uptake, metabolism, and behavioral effects of cannabinoids on zebrafish larvae
No full textThe Cannabis sativa plant contains numerous phytocannabinoids and terpenes with known or potential biological activity. For decades, plant breeders have been breeding the Cannabis plant to control for a desired ratio of the major cannabinoids. A high-throughput in vivo model to understand the relationship between the chemical composition of different strains and their therapeutic potential then becomes of value. Measuring changes in the behavioral patterns of zebrafish larvae is an established model with which to test the biological activity of neuroactive compounds. However, there is currently little information regarding the uptake kinetics and metabolism of compounds by larvae. In this study, we chose to compare the uptake kinetics and metabolism of \u394\u2079-tetrahydrocannabinol (THC) and cannabidiol (CBD) alone or in combination with their effects on larval behavior. We have shown that both compounds have distinct behavioral patterns and concentration response profiles. Additionally, the uptake kinetics observed for each compound appears to correlate with the change in behavior observed in the behavioral assays. When combinations of THC and CBD were tested there were shifts in both the behavioral activity and the uptake kinetics of each compound compared with when they were tested alone. Finally, the THC/CBD-derived metabolites detected in the larvae are similar to those found in mammalian systems. This study thus provides a model for further testing of additional cannabinoids and potentially plant extracts.Peer reviewed: YesNRC publication: Ye
A synchronized current-comparator-based power bridge for calibrating analog merging units
No full textA synchronized current-comparator-based power bridge for calibrating analog merging units at power frequencies of 60 Hz and 50 Hz is described. Analog merging units take analog signals from instrument transformers, convert them into digital form, pack the sampled values into Ethernet frames conforming to the IEC 61850-9-2 LE specification and stream the frames to other equipment in a digital substation for further processing. Since the sampled values are used for protection and metering, the merging units need to be calibrated. The expanded uncertainties (k=2) of the described calibration system are estimated to be better than 30 11A/A for magnitude and 60 \ub5rad for phase.Peer reviewed: YesNRC publication: Ye
The JILA (Parks-Falier) 2010 determination of the Newtonian constant
No full textWe present here an update of the JILA (Parks\uad Faller) 2010 determination of the Newtonian Constant of gravitation (big G). Due to an A bbe error that was unaccounted for in the initial analysis, we adjust our value of the gravitational constant G from (6.672 34 \ub1 0.000 14) x 10-11 m3 kg-1 s-2 to (6.672 96 \ub1 0.000 22) x 10-11 m3 kg-1 s-2. We discuss the source of the error and how it can be avoided in future iterations of this experiment.Peer reviewed: YesNRC publication: Ye
The stellar populations of two ultra-diffuse galaxies from optical and near-infrared photometry
No full textWe present observational constraints on the stellar populations of two ultra-diffuse galaxies (UDGs) using optical through near-infrared (NIR) spectral energy distribution (SED) fitting. Our analysis is enabled by new Spitzer-IRAC 3.6 and 4.5 \u3bcm imaging, archival optical imaging, and the prospector fully Bayesian SED fitting framework. Our sample contains one field UDG (DGSAT I), one Virgo cluster UDG (VCC 1287), and one Virgo cluster dwarf elliptical for comparison (VCC 1122). We find that the optical\u2013NIR colors of the three galaxies are significantly different from each other...Peer reviewed: YesNRC publication: Ye
Thermophysical property measurements of tetrabutylphosphonium acetate (TBPAce) ionic semiclathrate hydrate as thermal energy storage medium for general air conditioning systems
No full textThis paper reports the experimental study on measuring the phase equilibrium temperatures and the dissociation heats of ionic semiclathrate hydrate formed with tetrabutylphosphonium acetate (TBPAce) under atmospheric pressure. The phase equilibrium temperature and the dissociation heat measurements were performed in the range of the mass fraction of TBPAce aqueous solution from 0.10 to 0.42. The highest phase equilibrium temperature was 11.0\ub0C at the mass fraction range from 0.35 to 0.39. The largest dissociation heat of pure TBPAce hydrate was 192.0\u202fkJ kg\u20131 at the mass fraction 0.36. The obtained results indicate that TBPAce hydrate would be suitable for a new thermal energy storage medium for general air conditioning systems.Peer reviewed: YesNRC publication: Ye