Vaporsaver杜绝油站油气污染——美国麦迪逊市成功推广OPW油气封存冷凝系统

美国麦迪逊市的司机在油站加油时将会发现他们的呼吸会变得比以往顺畅,因为可以避免以往付出高价加油也要闻到的浓烈油气味。能够避免难闻的油气味归功于该市目前正在推广的绿色清洁加油站项目,此项目由当地环保局资助$50,000的费用对加油站进行改造,加油站通过使用油气处理系统将油气回收到地下油罐中,以避免油气排放到空气中,此项举措不仅能为油站带来效益,同时也能减少因为油气排放导致的臭氧增加而引起的空气污染。地区及联邦政府官员是在麦迪逊的PDQ加油站举办的记者会上宣布正式推广油气封存冷凝系统。“这是一个真正的利于周边邻镇…     

Role of triglycerides and phospholipids on development of rancidity in model meat systems during frozen storage

The effect of triglycerides, phospholipids and total lipids on development of rancidity during frozen storage at ?18° C for 8 months was studied using lipid-free muscle fibres in combination with added triglycerides, phospholipids and total lipids. Results showed that added phospholipids greatly increased TBA values. Oxidation took place in two stages. Phospholipids were the first to oxidise, with their rate of oxidation decreasing with time. Oxidation of the triglycerides began only after a prolonged induction period. Results demonstrated that both triglycerides and phospholipids contribute to development of rancidity, although phospholipids make the greatest contribution. The influence of triglycerides on the development of rancidity was shown to depend upon the degree of unsaturation and the length of time in frozen storage. The relationship between oxidation of the polyunsaturated fatty acids (PUFAS) of the phospholipids and development of rancidity was confirmed.     

Effect of a proteolytic enzyme produced by Clostridium perfringens upon porcine muscle

Purified proteolytic enzyme preparations isolated from actively growing cultures of Clostridium perfringens (ATCC 13124—Type A) were added to aseptic porcine muscle and incubated at 37°C. Samples were removed after one, two and four days incubation. The sarcoplasmic and myofibrillar proteins were extracted and subjected to both conventional and SDS-polyacrylamide disc gel electrophoresis to assess the changes due to the enzyme treatment. The enzyme preparation caused little change in the sarcoplasmic protein fraction but caused some proteolysis in the myofibrillar extract. Comparison of the protein profile from muscle incubated with the purified enzyme preparation and that incubated with the actively growing organisms per se showed that the organisms caused more degradation, suggesting that they produced additional enzymes causing proteolysis of porcine muscle.     

Some “Reflections” on the Effects of Finite Gradient Pulse Lengths in PGSE NMR Experiments in Restricted Systems

It is generally difficult to analytically derive models describing the echo attenuation in pulsed gradient spin-echo (PGSE) experiments for even the simplest porous systems that are commonly studied—especially when the gradient pulse (δ) is of finite length compared to the timescale of the diffusion measurement (Δ). Consequently, various levels of approximation are used to evaluate PGSE experiments. In the present paper, a conceptual view of q-space is given and two of the most common approximations, the short gradient pulse (SGP) and Gaussian phase distribution (GPD) approximations, are compared in detail with a recent matrix method, which provides “analytically” exact results giving a visual representation of the limitations of these approximations. The simulations are performed for diffusion between a pair of reflecting planes separated by a distance a. A modification that is sometimes applied to the short gradient pulse approximation in attempting to extend it to finite gradient pulses is also compared. The simulations reveal that, except when the experimental conditions closely match the requirements of the SGP and GPD simulations, the matrix method must be used in order to correctly interpret the data.     

Explosive behavior of aluminized ammonium perchlorate

addition of aluminum to ammonium perchlorate (AP) increases its infinite diameter detonation velocity and decreases its critical diameter. For 7–9 μ AP and 7 μ Al, the maximum of these effects occurred at about 10% Al. Regular detonation behavior could be observed only in the range 55-40% (or lower) theretical maximu density (TMD). All mixtures tested in this range exhibited Group 2 behavior as does AP itself.     

Structure-activity relationships for chain-shortened analogs of (Z)-5-decenyl acetate,a pheromone component of the turnip moth,Agrotis segetum

Structure-activity relationships for chain-shortened analogs of (Z)-5-decenyl acetate, a pheromone component of the turnip moth,Agrotis segetum, have been studied by electrophysiological single-sensillum technique and interpreted in terms of a previously reported receptor-interaction model. The results indicate that the terminal methyl group, as well as the acetate group, interacts with highly complementary receptor sites. The terminal alkyl chain is suggested to interact with a hydrophobic pocket extending over the two methylene groups closest to the terminal methyl group. The amounts of stimulus actually released from the odor source have been studied. The results demonstrate the necessity to take differences of volatility into account in comparisons of electrophysiological data for compounds of different chain lengths. It is shown that relative vapor pressures may to a good approximation be employed to estimate correction factors.Schiff., Lepidoptera: Noctuidae.     

A causal model for turnover for nurses.

Longitudinal data on 1,091 registered nurses in seven hospitals were used to estimate a causal model of turnover in organizations. Total effects on turnover were found to be the greatest for four determinants: intent to stay, opportunity, general training, and job satisfaction. The relative importance of the determinants of turnover and the explanatory power of the model are presented and discussed.