Thermo-economic investigation on the hydrogen production through the stored solar energy in a salinity gradient solar pond: A comparative study by employing APC and ORC with zeotropic mixture

In this paper, a salinity gradient solar pond (SGSP) is used to harness the solar energy for hydrogen production through two cycles. The first cycle includes an absorption power cycle (APC), a proton exchange membrane (PEM) electrolyzer, and a thermoelectric generator (TEG) unit; in the second one, an organic Rankine cycle (ORC) with the zeotropic mixture is used instead of APC. The cycles are analyzed through the thermoeconomic vantage point to discover the effect of key decision variables on the cycles’ performance. Finally, NSGA-II is used to optimize both cycles. The results indicate that employing ORC with zeotropic mixture leads to a better performance in comparison to utilizing APC. For the base mode, unit cost product (UCP), exergy, and energy efficiency when APC is employed are 59.9 $/GJ, 23.73%, and 3.84%, respectively. These amounts are 47.27 $/GJ, 29.48%, and 5.86% if ORC with the zeotropic mixture is utilized. The APC and ORC generators have the highest exergy destruction rate which is equal to 6.18 and 10.91 kW. In both cycles, the highest investment cost is related to the turbine and is 0.8275 $/h and 0.976 $/h for the first and second cycles, respectively. In the optimum state the energy efficiency, exergy efficiency, UCP, and H₂ production rate of the system enhances 42.44%, 27.54%,15.95%, and 38.24% when ORC with the zeotropic mixture is used. The maximum H₂ production is 0.47 kg/h, and is obtained when the mass fraction of R142b, LCZ temperature, pumps pressure ratio, generator bubble point temperature are 0.603, 364.35 K, 2.12, 337.67 K, respectively.     

莲心中可溶性成分的有效提取

采用不同的原料处理,改变提取的流程和提取时间，测定不同条件下所得提取液的可见吸收光谱，以此反映各提取液的组分和浓度是否发生变化，并比较在最大吸收波长下各提取液的吸光度大小，从而确定将莲心捣碎后，加热回流时间为60min的提取方法效果最佳。     

高密度澄清池在邯钢第二污水处理厂的应用

高密度澄清池是一种新型高效的澄清池。介绍了高密度澄清池的工艺原理、运行条件和主要参数及在邯钢第二污水处理厂的应用情况。     

Big-Fish--Little-Pond effect on academic self-concept: A cross-cultural (26-country) test of the negative effects of academically selective schools.

Academically selective schools are intended to affect academic self-concept positively, but theoretical and empirical research demonstrates that the effects are negative. The big-fish--little-pond effect (BFLPE), an application of social comparison theory to educational settings, posits that a student will have a lower academic self-concept in an academically selective school than in a nonselective school. This study, the largest cross-cultural study of the BFLPE ever undertaken, tested theoretical predictions for nationally representative samples of approximately 4,000 15-year-olds from each of 26 countries (N=103,558) who completed the same self-concept instrument and achievement tests. Consistent with the BFLPE, the effects of school-average achievement were negative in all 26 countries (M beta=-.20, SD=.08), demonstrating the BFLPE's cross-cultural generalizability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Solar ponds in alkaline lake and oil well regions

Solar ponds are probably the simplest technology available for the useful conversion of solar energy. The basic technology is proven. Solar ponds have been shown to be technically feasible and economically viable for many applications, particularly for thermal use. The electrical conversion and use of solar energy via solar ponds is still questionable, in general, for economic viability. By putting the untapped sources together in the South Plains region, it looks promising economically both for thermal and electrical conversions and applications. There are a number of alkaline lake basins randomly scattered in the South Plains region of the U.S.A. In that area, there are thousands of crude oil producing wells that produce brine in abundance. The selection of suitable alkaline lake basins as a solar pond site and as depository sites of brine from oil wells and the using of this brine and salty water from alkaline lakes makes the solar pond economically viable for both thermal and electrical demands in the area.     

气浮池──稳定塘处理造纸废水

叙述了用气浮地→厌氧塘→兼性塘处理造纸废水的试验与设计。经运行后测定，出水达到了天津市水污染物排放标准的要求。气浮池采用３０％的回流比，提高了处理效率，每天可回收纸板原料８．４～１０．８ｔ。     

基于SPOT-5多光谱影像的矿区塌塘水体提取方法研究

针对基于遥感影像的水体提取方法存在水体提取不完整和误提的现象,提出了一种基于SPOT-5多光谱影像的矿区塌塘水体提取方法。在利用波段合成增加一个可用波段的基础上对已有的水体提取方法进行适当的改进,并基于决策树分类器和改进后的方法进行矿区水体的四级提取,保证了水体提取的完整性,同时减少了误提率;最后利用实测数据对水体提取的精度进行了评定。试验结果表明,基于决策树分类器的水体提取方法具有较高的精度,能满足矿区实际应用的需要。     

天然藕丝的纤维特征

藕丝是一种天然纤维,扫描电镜显示其外型具有与藕的外型相同的节状特征,其单丝直径在微米尺寸范围内,平均强度约为1.3 cN,最大延伸率约为1.1%。DSC分析发现藕丝的玻璃化转变温度在43℃左右,而红外光谱则显示藕纤维主要含多糖物质。     

生态稳定塘系统在城市污水处理中的应用

介绍了生态稳定塘系统在德州市城市污水处理中的应用情况，对工程设计参数及其设计特色作了重点介绍，以资同行借鉴。     

自清洁外墙涂料的研究与应用

如何提高外墙涂料的自清洁能力,并使之保持较长的装饰效果一直是涂料界关注的热点。本文综述了微粉化技术、荷叶效应、气球陶瓷理论、自分层技术以及光催化效应的原理,及其在改善外墙涂料自清洁性方面的应用。