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Airborne and impact sound insulation data for cold-formed steel-framed walls and floors
No full textThis report presents the results of an extensive series of direct sound insulation tests of cold-formed steel-framed walls and floors. The direct airborne sound insulation of 30 walls with cold-formed steel framing was measured in accordance with ASTM E90-09. The walls had steel studs with a depth of 92 mm (3-5/8\u201d) or 152 mm (6\u201d), and with a steel thickness of 1.09 mm (0.043\u201d) or 1.37 mm (0.054\u201d). Other parameters that were investigated included the number of layers and thickness of gypsum board, the cavity insulation, the stud spacing, and the use of resilient channels. The test results for some non-standard wall configurations that were tested for research purposes (e.g. for walls with gypsum board on one side only) are also included in this report. The direct airborne and impact sound insulation of 17 floors with cold-formed steel framing was measured in accordance with ASTM E90-09 and ASTM E492-09, respectively. The floors had steel joists with a depth of 254 mm (10\u201d) or 317 mm (12.5\u201d), and with a steel thickness of 1.37 mm (0.054\u201d). The top surface of the floor/ceiling assemblies was composed of a corrugated steel deck with poured gypsum concrete, while the bottom surface was composed of a gypsum board ceiling on resilient channels. The influence of the joist depth and the number of layers and thickness of the ceiling gypsum board was investigated, as well as the influence of several floor coverings (e.g. laminate or carpet). The report presents the detailed specimen descriptions and specimen properties and the results from the standardized tests according to ASTM E90-09 and ASTM E492-09. Brief analyses of the parameters affecting the sound insulation of the steel-framed assemblies are provided. The tests presented in this report were part of a large research study that also included an investigation into the flanking sound transmission in cold-formed steel-framed buildings. The results of that study are described in the NRC Research Report RR-337, \u201cApparent Sound Insulation in Cold-Formed Steel-Framed Buildings\u201d [1]. The NRC Research Report RR-337 also includes some of the airborne sound insulation results presented here, albeit without listing the detailed specimen descriptions and specimen properties that are provided in this report.Peer reviewed: NoNRC publication: Ye
Reply to the \u2018Comment on \u201cMethanol dimer formation drastically enhances hydrogen abstraction from methanol by OH at low temperature\u201d\u2019 by W. Siebrand, Z. Smedarchina, E. Mart\uednez-N\ufa\uf1ez and A. Fern\ue1ndez-Ramos, Phys. Chem. Chem. Phys., 2016, 18, 22712
No full textPeer reviewed: YesNRC publication: Ye
Analysis of the pharmacological properties of JWH-122 isomers and THJ-2201, RCS-4 and AB-CHMINACA in HEK293T cells and hippocampal neurons
No full textSynthetic cannabinoids are marketed as legal alternatives to \u3949-THC, and are a growing worldwide concern as these drugs are associated with severe adverse effects. Unfortunately, insufficient information regarding the physiological and pharmacological effects of emerging synthetic cannabinoids (ESCs) makes their regulation by government authorities difficult. One strategy used to evade regulation is to distribute isomers of regulated synthetic cannabinoids. This study characterized the pharmacological properties of a panel of ESCs in comparison to \u3949-THC, as well as six JWH-122 isomers relative to its parent compound (JWH-122-4). Two cell-based assays were used to determine the potency and efficacy of ESCs and a panel of reference cannabinoids. HEK293T cells were transfected with human cannabinoid receptor 1 (CB1) and pGloSensor-22F, and the inhibition of forskolin-stimulated cyclic adenosine monophosphate (cAMP) levels was monitored in live cells. All ESCs examined were classified as agonists, with the following rank order of potency: Win 55,212-2 > CP 55,940 > JWH-122-4 > \u3949-THC 48 RCS-4 48 THJ-2201 > JWH-122-5 > JWH-122-7 > JWH-122-2 48 AB-CHMINACA > JWH-122-8 > JWH-122-6 > JWH-122-3. Evaluation of ESC-stimulated Ca2+ transients in cultured rat primary hippocampal neurons confirmed the efficacy of four of the most potent ESCs (JWH-122-4, JWH-122-5, JWH-122-7 and AB-CHMINACA). This work helps regulatory agencies make informed decisions concerning these poorly characterized recreational drugs.Peer reviewed: YesNRC publication: Ye
A virgo environmental survey tracing ionised gas emission (VESTIGE).I. introduction to the survey
No full textThe Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE) is a blind narrow-band Halpha+[NII] imaging survey carried out with MegaCam at the Canada-France-Hawaii Telescope. The survey covers the whole Virgo cluster region from its core to one virial radius (104 deg^2). The sensitivity of the survey is of f(Halpha) ~ 4 x 10^-17 erg sec-1 cm^-2 (5 sigma detection limit) for point sources and Sigma (Halpha) ~ 2 x 10^-18 erg sec^-1 cm^-2 arcsec^-2 (1 sigma detection limit at 3 arcsec resolution) for extended sources, making VESTIGE the deepest and largest blind narrow-band survey of a nearby cluster. This paper presents the survey in all its technical aspects, including the survey design, the observing strategy, the achieved sensitivity in both the narrow-band Halpha+[NII] and in the broad-band r filter used for the stellar continuum subtraction, the data reduction, calibration, and products, as well as its status after the first observing semester. We briefly describe the Halpha properties of galaxies located in a 4x1 deg^2 strip in the core of the cluster north of M87, where several extended tails of ionised gas are detected. This paper also lists the main scientific motivations of VESTIGE, which include the study of the effects of the environment on galaxy evolution, the fate of the stripped gas in cluster objects, the star formation process in nearby galaxies of different type and stellar mass, the determination of the Halpha luminosity function and of the Halpha scaling relations down to ~ 10^6 Mo stellar mass objects, and the reconstruction of the dynamical structure of the Virgo cluster. This unique set of data will also be used to study the HII luminosity function in hundreds of galaxies, the diffuse Halpha+[NII] emission of the Milky Way at high Galactic latitude, and the properties of emission line galaxies at high redshift.Peer reviewed: YesNRC publication: Ye
Design and synthesis of new fullerene derivatives for organic solar cells
No full textBulk heterojunction (BHJ) organic solar cells based on p-type polymers and n-type fullerene derivatives have attracted increasing attention due to their promising potential for providing low\u2013cost solar electricity. In this paper, we will introduce our recent work on the development of new fullerene derivatives. Through Rh complex catalyzed coupling reactions and cycloaddition reactions, we attached several organic functional groups to the fullerene skeleton. It was found that the organic substituents had little impact on the fullerene energy levels. Instead, the organic substituents have huge impact on the other physical properties of the resulting fullerene derivatives, such as solubility, crystallinity, and electron mobility. We designed and synthesized a novel series of alkoxy substituted indene derivatives as solubilizing groups for fullerenes. Preliminary experimental results demonstrated that these 5-alkoxyindene modified C70 derivatives are superior to widely used PC71BM when blended with poly[N-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'- benzothiadiazole)](PCDTBT) in BHJ solar cells. The device series resistance decreased from 10 cm2 for the PC71BM based device to 4 cm2 for the 5-methoxyindene-C70 monoadduct based device. As a result, the device fill factor increased from 0.60 to 0.69, and the overall EQE-calibrated power conversion efficiency was enhanced from 5.6% to 6.2%.Peer reviewed: YesNRC publication: Ye
Experimental and numerical investigations of soot formation in laminar coflow ethylene flames burning in O2/N2 and O2/CO2 atmospheres at different O2 mole fractions
No full textThis paper presents an experimental and numerical study of the distributions of the temperature and soot volume fraction in laminar coflow ethylene diffusion flames burning in O2/N2 and O2/CO2 atmospheres with the O2 mole fraction varying from 21 to 50% in both atmospheres. The fuel flow rate was maintained constant in all of the experiments and simulations. The two-color flame emission method based on the response spectrum of R and G bands of a three-color charge-coupled device camera was applied to measure the temperature and soot volume fraction. Numerical calculations were conducted using the C2 chemistry model [Appel\u2013Bockhorn\u2013Frenklach (ABF), Appel, J.; Bockhorn, H.; Frenklach, M. Kinetic modeling of soot formation with detailed chemistry and physics: Laminar premixed flames of C2 hydrocarbons. Combust. Flame 2000, 121 (1\u20132), 122\u2013136, DOI: 10.1016/S0010-2180(99)00135-2] with formation of polycyclic aromatic hydrocarbons (PAHs) up to pyrene and a soot model incorporating the dimerization of two pyrene molecules as the soot inception step and hydrogen-abstraction acetylene addition mechanism and PAH condensation as the surface growth processes. Numerical results are in qualitative agreement with the experimental measurements when the oxidizer stream is air. The numerical model predicts the temperature well but overpredicts the soot volume fraction in oxygen-enriched flames in both O2/N2 and O2/CO2 atmospheres. With the increase of the oxygen mole fraction in the oxidizer stream, the flame becomes brighter and shorter, the peak temperature zone shifts from the flame wing to the upper part, and the peak soot volume fraction moves from the flame wing to the flame center. The soot loading grows rapidly with increasing the oxygen mole fraction in the oxidizer stream. Under the same oxygen mole fraction, the temperature and soot volume fraction in the O2/N2 atmosphere are always higher than those in the O2/CO2 atmosphere as a result of the higher heat capacity of CO2 and soot formation suppression by CO2. The chemical effect of CO2 may promote O and OH, which enhance the oxidation of the critical soot formation species, including H, C2H2, C6H6, and C16H10. The primary pathway for the chemical effect of CO2 is its competition for the H radical to form CO and OH, i.e., CO2 + H \u21c4 CO + OH. Soot formation in these flames is affected by two primary reactions: CO2 + H \u21c4 CO + OH and H + O2 \u21c4 O + OH.Peer reviewed: YesNRC publication: Ye
Extracting nonradiative parameters in III\u2013V semiconductors using double heterostructures on active p-n junctions
No full textA novel method of extracting the nonradiative lifetime of Ga 0.51 In 0.49 P lattice matched to GaAs by exploiting luminescence coupling is discussed. The method requires a GaInP double heterostructure monolithically grown on a GaAs photodetector for quantum efficiency measurements. The method then extracts the nonradiative lifetime by modeling the luminescence coupling between the GaInP and the GaAs active region. The bulk nonradiative lifetime of disordered GaInP doped to 10 17 cm -3 under low-level injection (~4
7 10 12 cm -3 ) is determined to be 47 ns for GaInP layer thicknesses ranging from 200 to 1500 nm, with a surface recombination velocity of 660 cm/s. The results are in agreement with nonradiative lifetimes extracted using power-dependent relative photoluminescence measurements, whereby the lifetimes increase as a function of injection level to 0.5 \u3bcs. Surface recombination velocities are also reported as a function of injection level using this technique, decreasing from 1800 cm/s under low injection to 50 cm/s under high injection (~10 17 cm -3 ). Lastly, the effective radiative lifetimes (accounting for photon recycling) are also reported for the studied GaInP samples.Peer reviewed: YesNRC publication: N
Femtosecond laser-inscribed fiber bragg gratings for sensing applications
No full textThis chapter presents the state of the art of femtosecond laser\u2013induced fiber Bragg gratings for sensing applications. It summarizes the laser-material processing mechanisms for dielectric modification with femtosecond pulse duration sources, techniques for grating inscription with said sources, and applications of femtosecond laser\u2013induced gratings in waveguides for strain, temperature, and chemical sensing in harsh environments.Peer reviewed: YesNRC publication: Ye