Helium dispersion following release in a 1/4-scale two-car residential garage

A series of experiments are described in which helium was released at a constant rate into a 1.5 m × 1.5 m × 0.75 m enclosure designed as a 1/4-scale model of a two-car garage. The purpose was to provide reference datasets for testing and validating computational fluid dynamics (CFD) models and to experimentally characterize the effects of a number of variables on the mixing behavior within an enclosure and the exchange of helium with the outside surroundings. Helium was used as a surrogate for hydrogen, and the total volume released was scaled as the amount that would be released by a typical hydrogen-fueled automobile with a full tank. Temporal profiles of helium were measured at seven vertical locations within the enclosure during and following 1-h and 4-h releases. Idealized vents in one wall sized to provide air exchange rates typical of actual garages were used. The effects of vent size, number, and location were investigated using three different vent combinations. The dependence on leak location was considered by releasing helium at three different points within the enclosure.     

Defining the infrared systems for ITER

The International Thermonuclear Experimental Reactor will have wide angle viewing systems and a divertor thermography diagnostic, which shall provide infrared coverage of the divertor and large parts of the first wall surfaces with spatial and temporal resolution adequate for operational purposes and higher resolved details of the divertor and other areas for physics investigations. We propose specifications for each system such that they jointly respond to the requirements. Risk analysis driven priorities for future work concern mirror degradation, interfaces with other diagnostics, radiation damage to refractive optics, reflections, and the development of calibration and measurement methods for varying optical and thermal target properties.     

Improving the Sensitivity of FAB Tandem Mass Spectrometry for PAH-DNA Adducts

Abstract

The mass spectrometric detection limits for guanine, adenine, and an adeninddimethylbenthracene adduct were greatly improved by converting the materials to pentafluorobenzyl derivatives, as well as by doing coaxial continuous flow-FAB (coaxial cf-Fast Atom Bombardment). The lowest detection limit (approximately 10 pg) was achieved when the derivatized sample was introduced by coaxial cf-FAB and the determination was by fill-scan mass spectrometry. The lowest detection limit achieved by tandem mass spectrometry was 50 pg obtained after derivatization, coaxial cf-FAB introduction and detection with an extended mass range array.     

La face cachée de l'effet protecteur du désengagement psychologique au travail: Le cas des policiers.

This study has two goals. The first is to provide more information on the asymmetrical and negative link between psychological disengagement mechanisms and self-esteem level. The second is to pursue the investigation of the protective effect of psychological disengagement via the evaluation of another facet of self-esteem that is, its stability. This study conducted amongst 152 policemen confirms that disengagement allows individuals to secure their self-esteem stability. Results militate in favour of the occupation's social status to explain the variable association between disengagement and self-esteem level. In the discussion, we raise the veil on the hidden face of the protective effect of disengagement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reactor Comparison for the Esterification of Fatty Acids from Waste Cooking Oil

Esterification of the fatty acids contained in waste cooking oil with glycerol, a reaction involving immiscible and viscous reactants, was achieved in two pilot‐scale continuous pulsed reactors: the oscillatory baffled reactor and the helix reactor. In both reactors, with or without baffles, the reaction reaches its thermodynamic equilibrium at lower temperatures, shorter residence times and with higher selectivities than those reported in the literature. This equilibrium is then shifted by an increase in the excess of glycerol, or by removing water from the reactive media by an intermediary decantation or by the use of dodecylbenzene sulfonic acid, a surfactant catalyst. Further investigations would be required to increase the conversions without decreasing the selectivities, by increasing the initial amount of free fatty acids.     

Opioids and rate of positively reinforced behavior: II. Antagonism by β-funaltrexamine.

Lever pressing by rats (Rattus norvegicus) was maintained under a fixed-ratio 20 schedule of food presentation. Response rate-decreasing effects of the opioid compounds fentanyl, U50,488, butorphanol, and nalorphine were examined alone and in combination with the irreversible, μ-selective opioid antagonist β-funaltrexamine (β-FNA) antagonized the rate-decreasingly effects of both fentanyl and butorphanol. β-FNA was more potent and the duration of antagonism was greater, against butorphanol than against fentanyl. β-FNA also antagonized the effects of the higher nalorphine doses: however, lower doses of nalorphine, which were without effect alone, decreased response rates in the presence of β-FNA. The dose–effect curve for U50,488 was shifted leftward in the presence of β-FNA. These data suggest that, β-FNA may be useful in assessing μ-receptor activity related to the effects of opioids on rate of operant behavior and the efficacy with which opioids produce these effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Teachers' coaching of learning and its relation to students' strategic learning.

This study examined types and frequency of coaching of learning at the middle school level and its relation to students' strategic learning. Teachers (n?=?11) were videotaped during daily instruction on 3 separate occasions, and students (n?=?235) responded to a self-report questionnaire about learning-strategy use. Consistent with previous research at the elementary level (E. B. Moely et al., 1992), average instances of teachers' coaching of learning (e.g., describing cognitive processes, suggesting strategy use) occurred in only 9% of the instruction segments. Teachers most frequently recommended use of learning aids, engagement in metacognitive activity, and use of elaboration strategies. Results from a multiple regression analysis indicate that students' strategic-learning activity was significantly related to teachers' coaching of learning (R2?=?.18). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cu diffusion in Ag-plated Cu leadframe packages

Cu diffusion onto an Ag-plated Cu leadframe surface was detected by Energy Dispersive X-ray (EDX) after de-capsulating the molded package. However, no Cu was detected by EDX on the Ag surfaces of bare leadframe, leadframe after die attachment including die attachment curing, or leadframe after wire bonding. Temperature simulation of molding and post-molding curing show that the temperature and its duration have some impact on the Cu diffusion, which is as expected. Interestingly, this study shows that the Cu diffusion onto the interface of the Ag-plated surface and mold compound is very much dependent on the type of mold compound used, which has never been reported in the literature so far. The Cu diffusion was detected by EDX only for certain types of mold compounds used. It is concluded that the mold compound is a major contributor to the Cu diffusion observed. This is possibly because S and O in the mold compound react with Cu and form copper sulfides and copper oxides, which accelerate the Cu diffusion from the Cu leadframe substrate onto the interface of the Ag surface and mold compound.