Optimum integration of solar technologies into an existing hydrothermal power system

A linear programming model is presented for optimizing the integration of solar-based generation technologies into an existing hydrothermal generation system in such a way as to avoid the storage costs usually associated with such technologies. The optimization model is applied to the particular problem of meeting the projected generation requirements in Washington State during the year 2000. Numerical calculations are performed to determine the optimum combination of five new technologies (wind, photovoltaics, small hydro, cogeneration, total energy systems) as additions to the existing hydrothermal system. Several scenarios are explored and required deployment rates are calculated. The results indicate that the extent and pattern of integration of these new technologies can be sharply affected by the management strategies applied to the existing hydrothermal system.     

National Institute of Mental Health goals for behavioral science.

Because all health conditions for which the National Institute of Mental Health (NIMH) is responsible manifest at the level of behavior, and all interventions must have an impact at the behavioral level, NIMH is firmly committed to the support of behavioral science. In an era in which research in areas that some view as reductionist—for example, genomics, genetics, functional genomics and proteomics, and molecular science—is especially promising, NIMH is striving to maintain a balance in its portfolio with studies that explore integrative aspects of biology, including behavior. Without this perspective, new information about fundamental processes will prove ultimately to be shallow. This commentary discusses how understanding of brain and behavior in mental illness and health calls for integrating bottom-up research that studies brain and behavior through genes and molecules, with top-down research that examines the impact of environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hydrolysis of tert-butyl methyl ether (MTBE) in dilute aqueous acid

tert-Butyl methyl ether (MTBE) is generally considered to be resistant to chemical transformation in aqueous solution. This lack of reactivity has led to concerns of the long-term impacts of MTBE in groundwater. Although hydrolysis in the presence of strong acids has been recognized as a mechanism for MTBE transformation, it has been discounted as a significant reaction under environmental conditions. In this study, we have examined the fate of MTBE and other ether oxygenates under moderately acidic conditions (> or=pH 1). The results demonstrate that MTBE is sensitive to acid-catalyzed hydrolysis reaction that generates tert-butyl alcohol (TBA) and methanol as products. The reaction is first-order with respect to the concentration of MTBE and hydronium ion with a second-order rate constant of about 0.9 x 10(-2) M(-1) h(-1) at 26 degrees C. Commercially available acidic ion-exchange resins were also shown to catalyze the hydrolysis of MTBE at near neutral pH. Pseudo-first-order rate constants were observed to be as high as 0.03 h(-1) at 25 degrees C and 0.12 h(-1) at 35 degrees C. These findings are discussed in terms of their possible implications for the treatment and environmental fate of MTBE and other gasoline oxygenates.     

ZnO 气敏材料的研究进展

本文着重介绍了粉末状 Zn O气敏材料的制备和掺杂的研究进展 ,并指出了存在的问题和今后发展的方向     

DIRECT CATALYTIC CONVERSION OF METHANE TO HIGHER HYDROCARBONS

Abstract

Using a plug-flow reactor we have been able to demonstrate the conversion of pure methane gas to liquid hydrocarbons via the intermediate formation of methanol. The reaction Was carried out at an intermediate pressure (about 20 atm) and moderate temperature (about 400°C). In the first stage of the reactor methane and oxygen react to produce methanol. In the second stage the methanol was converted by HZSM-5 catalyst to a mixture of hydrocarbons. Analysis of the reaction products showed that all of the oxygen Was used in the reaction. Apart from the unconverted methane the product was composed of oxides of carboy water and C₃+ hydrocarbons. Interestingly, among the liquid hydrocarbons, aromatics were found to be the major constituents.     

Tracking the impact of microenterprise programs: the experience of nongovernmental organizations

In September 1995, US AID funded a five-year project on Assessing the Impact of Microenterprise Services (AIMS). Initially AIMS supported a survey to determine existing practices among 41 members of the Small Enterprise Education and Promotion Network (SEEP) and several associated overseas programs. The most commonly perceived weaknesses of the NGOs' impact information systems were insufficient rigor and reliability of data, inability to collect the desired information, lack of standard indicators, and difficulties obtaining timely data. The main reported strengths were simplicity and low cost     

基于两分量法在中性点不接地系统应用研究

由对称分量导出了两分量法,分析了两分量法解电力系统故障方法及与对称分量间关系,得出中性点不接地系统相间故障用差量解相间故障的方法。分析了差量选相原理,提出了采用差量突变量单端测距理论基础,测距精度满足工程要求。提出了中性点不接地系统只有两相装设电流互感器求解差量处理方法。