Depletion of Antioxidants from a HDPE Geomembrane in a Composite Liner

The results of two series of accelerated aging tests are reported. Both series of tests were conducted at temperatures of 85, 70, 55, and 26°C over a period of about 3?years. In the simulated liner series, the top of the geomembrane was covered with a geotextile (protection) layer that was exposed to simulated municipal solid waste (MSW) landfill leachate while the bottom of the geomembrane was in contact with a hydrated geosynthetic clay liner. In the immersion series, the geomembrane was immersed in the simulated MSW leachate, and hence, both sides were exposed to leachate. The results from oxidative induction time tests indicate that the antioxidant depletion is about 2.2–4.8 times faster for the leachate immersed geomembrane than for geomembrane in a composite liner. The higher rates are attributed to the higher extraction of antioxidants from two sides of the geomembrane immersed in leachate. The measured antioxidant depletion rates are extrapolated to a range of temperatures (0–60°C) using Arrhenius modeling. At a liner temperature of 35°C, the calculated time for the depletion of antioxidants is about 40?years for a geomembrane in a composite liner compared to 10?years if it is simply immersed in leachate. These tests suggest that to obtain realistic estimates of geomembrane service life one needs data from tests that simulate the expected field conditions and that prediction based on immersion tests may underestimate the service life.     

FPGA推动多用户信息娱乐功能

汽车的信息娱乐特性和功能随着每一代车辆而发展。对于汽车的信息娱乐，几乎每个人都关注经典的4门轿车。那么乘载不同偏爱的8个或更多人员的车辆又会怎样呢？同时向每一位乘客发送唯一的媒体流是可能的，就像飞机上的乘客有广泛的视频、音频甚至游戏选择。汽车的信息娱乐功能迅速地成为在航空市场找得到的东西的扩展。一些具有通信系统的汽车的多媒体功能能够访问Internet，     

Aging of HDPE Geomembrane in Three Composite Landfill Liner Configurations

Laboratory-accelerated aging experiments conducted to examine the depletion of antioxidant from a geomembrane (GM) underlain by a geosynthetic clay liner (GCL) are described. Three different “protection” layers between the GM and overlying gravel and leachate are examined: (1) A traditional nonwoven geotextile (GT); (2) a GT-GCL; and (3) a GT-sand-GT layer. The GT-GCL protection layer gives an antioxidant depletion rate 0.59 to 0.66 times slower than the GT layer alone. The GT-sand-GT layer gives depletion rates 0.72–0.75 times that of the conventional GT alone. Based on Arrhenius modeling, the time required for depletion of antioxidants at 35°C is estimated to be 65 years for a GM with a GT-GCL protection layer, 50 years for a GT-sand-GT layer, and 40 years for a conventional GT protection layer. These times are all significantly greater than the depletion time for GM immersed in leachate (10 years) for the geomembrane tested.     

Using full matching to estimate causal effects in nonexperimental studies: Examining the relationship between adolescent marijuana use and adult outcomes.

Matching methods such as nearest neighbor propensity score matching are increasingly popular techniques for controlling confounding in nonexperimental studies. However, simple k:1 matching methods, which select k well-matched comparison individuals for each treated individual, are sometimes criticized for being overly restrictive and discarding data (the unmatched comparison individuals). The authors illustrate the use of a more flexible method called full matching. Full matching makes use of all individuals in the data by forming a series of matched sets in which each set has either 1 treated individual and multiple comparison individuals or 1 comparison individual and multiple treated individuals. Full matching has been shown to be particularly effective at reducing bias due to observed confounding variables. The authors illustrate this approach using data from the Woodlawn Study, examining the relationship between adolescent marijuana use and adult outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intermediate temperature oxidation in silicon nitride yttria ceramics

Silicon nitride billets with both 4% and 8% Y₂O₃ additives have been subjected to oxidation treatments for up to 300 h, in air, in the temperature range 700 to 1000° C. Flexure strength and weight gain measurements together with both scanning and transmission electron microscopy and X-ray diffraction studies were conducted on these billets in an effort to understand the oxidation process. It appears that the degradation phenomena is associated with both the formation of phases outside the Si₃N₄-Si₂ON₂-Y₂Si₂O₇ compatibility triangle of the system Si₃N₄-SiO₂-Y₂O₃ and with the decomposition of W-containing phases at and near the grain boundaries.     

Evaluation of surimi, fat and water content in a low/no added pork sausage formulation using response surface methodology

Response surface methodology (RSM) was employed for simultaneous analysis of the effects of added surimi (0-40%), fat (5-30%) and water (10-35%), on the physical, textural and sensory characteristics of fresh breakfast pork sausages. Experimental design allowed for evaluation of potential interactive effects between these ingredients. Sausages were evaluated for texture, colour, water holding capacity (WHC) and sensory attributes. Three optimum recipes, R1 (25.3% surimi, 22.2% fat, 12.7% water, 25.3% pork), R2 (12.2% surimi, 5.5% fat, 38.7% water, 33.2% pork) and R3 (25.3% surimi, 6.3% fat, 28.5% water, 25.3% pork), were determined and these were evaluated against a full-fat commercial control (R4). Force values of R1 were not significantly different to R4, however, force values for R2 and R3 were lower (P<0.001). No significant differences were observed between R1, R3 and R4 for visual colour or sensory acceptability scores throughout the study, whereas scores for R2 were lower. Sensory analysis indicated that R2 had lower scores for texture (P<0.01), chewiness (P<0.01), acceptability (P<0.01), flavour (P<0.05) and preference (P<0.01). Results from this study suggest that it is possible to successfully replace pork meat with functional fish proteins in the manufacture of sausage type products.     

Bioaccumulation, biotransformation, and biochemical effects of brominated diphenyl ethers in juvenile lake trout (Salvelinus namaycush)

Juvenile lake trout (Salvelinus namaycush) were exposed to three dietary concentrations (0, approximately 2.5, and approximately 25 ng/g per BDE congener) of 13 BDE congeners (3-10 Br atoms) in the laboratory for 56 days, followed by 112 days of clean food, to examine bioaccumulation parameters and potential biochemical effects. The bioaccumulation of BDEs by the trout was highly influenced by biotransformation, via debromination, which resulted in bioaccumulation parameters that were much different than would be expected based on studies of chlorinated organic compounds (e.g., PCBs). Half-lives (t1/2's) for some BDE congeners (e.g., BDE-85 and -190) were much lower than expected based on their Kow, which was likely due to biotransformation, whereas t1/2's of other BDE congeners (e.g., BDE-66, -77, -153, and -154) were much longer than anticipated based on Kow. This was likely because the metabolites of BDE formed via debromination had the same chemical structure of these BDE congeners, which supplemented measured concentrations. The detection of three BDE congeners (an unknown penta, BDE-140, and an unknown hexa) in the fish that were not present in the food or in the control fish provide further evidence forthe debromination of BDEs. Half-lives of BDEs ranged from 38 +/- 9 to 346 +/- 173 days and biomagnification factors ranged from 1.6 (BDE-190) to 45.9 (BDE-100), but these bioaccumulation parameters need to be viewed with caution because they were highly influenced by debromination and relative abundance of individual BDEs that the fish were exposed to. CYP1A enzyme activity, measured as EROD, and free tri-iodothyronine (T3) concentrations in the plasma of lake trout varied significantly throughout the experiment but were not related to BDE exposure. In contrast, plasma levels of thyroxine levels (T4) were lower in both groups of PBDE-exposed fish compared with control fish after 56 days of exposure, and after 168 days in the high dose, suggesting that PBDEs may influence thyroid homeostasis at levels that are higher than what is normally found in the environment.     

Application and assessment of extruded edible casings manufactured from pectin and gelatin/sodium alginate blends for use with breakfast pork sausage

Casings formed from pectin (PN) containing 2.5% and 5% corn oil (CO) and olive oil (OO) and gelatine/sodium alginate blends (GSAB) containing 2.5% CO and OO respectively were used for sausage manufacture. Mechanical properties and water content of casings were assessed prior to application. Following sausage manufacture, product quality and shelf-life evaluation were assessed in terms of sensory attributes, instrumental colour, moisture loss and lipid oxidation. All manufactured casings were of good quality and initially produced intact and stable sausage products. However, with time, shrinkage of products occurred where GSAB casings were used. Sensory analysis of sausages showed that PN casings were more preferred to GSAB casings for sausage manufacture. CIE colour analysis supported sensory evaluation. Water losses from sausages using GSAB casings were lower compared to sausages using PN casings due to GSAB casings having higher ability to trap and absorb water compared to PN casings. Lipid oxidation developed over time for all sausage products, however, sausages manufactured using GSAB casings containing both CO and OO at 2.5% had better oxygen barrier properties compared to sausages manufactured using PN containing the same concentration of emulsified oils. Sausages manufactured using casings containing OO were more prone to lipid oxidation than those using CO. Importantly, sausages manufactured using PN casings containing 5.0% CO were extremely stable to lipid oxidation over a six day storage period and significantly, were <1 on the TBARS numbers scale.     

Higher-order model of resilience in the Canadian forces.

Psychological resilience is an important construct for those who work in high-stress, potentially traumatic occupations. Using data collected as part of the Canadian Forces (CF) Recruit Health Questionnaire (RHQ), structural equation modelling analyses were performed to test the fit of a model of resilience comprised of several intrapersonal resilience factors (i.e., Big Five personality traits, dispositional affect, dispositional optimism, hardiness, mastery, self-esteem) and one interpersonal resilience factor (i.e., social support). An initial model showed that all lower-order intrapersonal variables loaded significantly onto a higher-order intrapersonal resilience latent factor, and that this factor was significantly correlated with social support. However, the strong intercorrelations between a few of the intrapersonal variables pointed to some redundancy. Based on empirical data and on a conceptual analysis, an alternative, more parsimonious model of resilience was developed. This model consisted of the Big Five personality traits, positive affect, and mastery as lower-order factors of dispositional resilience, which was hypothesised to be correlated with social support. This analysis is an important first step to developing an approach to conceptualise and measure resilience. One benefit of being able to assess resilience is that doing so can inform the development of programs to enhance mental health, readiness and recovery. However, more research is needed to understand the processes through which these psychological factors influence occupational as well as health outcomes before relevant policies may be developed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)