Numerical study of evaporation by mixed convection of a binary liquid film

This paper deals with a numerical analysis of the evaporation of binary liquid film. The film is falling down on one plate of a vertical channel under mixed convection channel. The first plate of a vertical channel is externally submitted to a uniform heated flux q₁ while the second one (y = d) is dry and isothermal. The liquid mixture consists of water (the more volatile component) and ethylene glycol while the gas mixture has three components: dry air, water vapour and ethylene-glycol vapour. The results concern the effects of the inlet parameters in the gas and in the liquid film on the interfacial pressure, temperature and concentration profiles. The evolutions of the heat fluxes and of the water and mixture evaporation rates have been analysed. Results obtained show, in particular, that it is possible to increase the accumulated evaporation rate of water and of the liquid mixture when the inlet liquid concentration of ethylene glycol (the less volatile component) is less than 40%. This result has been explained by the fact that an increase of the inlet liquid concentration of ethylene glycol has two antagonistic effects on the accumulated evaporation rates of water and of liquid mixture.     

Learned avoidance of flavors signaling reduction in a nutrient.

Food-deprived rats learned to avoid a flavor negatively correlated with access to a rich nutrient, 20% maltodextrin (20M) solution. This avoidance in two-bottle choice tests was produced by training consisting of either an unpaired condition where sessions of unflavored 20M were intermixed with sessions of 2 or 3% maltodextrin (2M or 3M) flavored with salt (Experiment 1) or almond (Experiments 3 and 4) or a differential conditioning procedure where one flavor was mixed with 20M and another with 2M (Experiment 2). Avoidance was counter-conditioned by mixing the target flavor with 20M (Experiment 1), generalized to a neutral context (Experiment 3), and displayed strong resistance to extinction (Experiment 4). The results demonstrated that food avoidance learning can occur in the absence of an aversive unconditioned stimulus and indicated that unpaired control groups and differential conditioning procedures may be misleading in flavor preference learning research when further control conditions are absent. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Integrated Framework for Quantifying and Predicting Weather-Related Highway Construction Delays

Constant exposure to the environment makes highway construction highly dependent on weather. However, highway construction contracts are often unclear about the potential influence of weather-related delays on highway construction project schedules. There is a need to discourage litigation arising from weather-related delays by including in contracts a reasonable number of nonwork days as a consequence of adverse weather and providing an equitable criteria for the course of action when the predictions in the contracts turn out to be inaccurate. To address this need, an integrated framework consisting of the following two key components is proposed: (1) identification of attributes of weather that cause construction delays and (2) generation of synthetic weather sequences using a stochastic weather generator to quantify and provide probabilistic forecasts of weather threshold values. The utility of this framework is demonstrated through its application to construction work on a project in Texas. The use of probabilistic forecast of construction delay attributes provided by a semiparametric weather generator in this research is an example of interdisciplinary study to help address this problem. The result of the research is better decision support for agencies who wish to author contracts that more equitably allow for the influence of weather during construction.     

Cu45Zr42.55Y3.45Al9非晶合金的热塑性

采用铜模铸造法制备Cu45Zr42.55Y3.45Al9块体非晶合金,利用三点压弯式粘度仪测定了合金在过冷液区附近的粘度,对合金进行热塑性性能的研究.通过计算得到Cu45Zr42.55Y3.45Al9非晶合金的脆性参数m为31,衡量非晶合金的热塑性加工性能参数m·△T*rx为3.1.在与已报道的有很好可塑性的Cu46Zr42Y5Al7非晶合金比较,可知Cu45Zr42.55Y3.45Al9非晶合金有更好的热塑性性能.此外少量Y元素的添加影响了非晶合金的热塑性.     

低碳经济时代的中国炼油工业

介绍了2010-2050年世界和中国石油消耗和利用的预测结果,分析了低碳经济时代的中国能源格局,即从一次能源到终端利用的格局,阐述了低碳经济时代中国能源产业面临的挑战和机遇,特别是中国炼油工业面临的挑战和机遇。只要能够跟上快速的科技进步的步伐,不断自主创新、集成创新,中国炼油工业就能充满信心地迎接各种转型的挑战,抓住低碳经济带来的一系列新的机遇,走向新的辉煌。     

Properties of InAs grown on misoriented GaAs substrates by atmospheric pressure metal–organic vapor phase epitaxy

InAs epilayers were grown by atmospheric pressure metal–organic vapor phase epitaxy on GaAs (1 0 0) exactly oriented substrates and misoriented by 2° and 10° toward [1 1 1]A. The layers had varying thicknesses and were deposited under the same growth conditions. Atomic force microscopy analysis show that surface morphology depends on surface misorientation and presents a low root mean square. High resolution X-ray diffraction analysis and Hall effect measurements were preformed to check the substrate misorientation effect on the crystalline quality and electrical properties respectively.     

Numerical simulation of heat and mass transfer in metal hydride hydrogen storage tanks for fuel cell vehicles

This paper presents a two-dimensional mathematical model to optimized heat and mass transfer in metal hydride storage tanks (hereinafter MHSTs) for fuel cell vehicles, equipped with finned spiral tube heat exchangers. This model which considers complex heat and mass transfer was numerically solved and validated by comparison with experimental data and a good agreement is obtained.     

Experimental studies on bubble pump operated diffusion absorption machine based on light hydrocarbons for solar cooling

An experimental investigation of an air-cooled diffusion absorption machine operating with a binary light hydrocarbon mixture (C₄H₁₀/C₉H₂₀) as working fluids and helium as pressure equalizing inert gas is presented in this paper. The machine, made of copper an available and very good heat conducting metal, is intended to be solar powered heat from flat plate or common evacuated tube collectors. The cooling capacity is 40–47 W respectively for 9 and 11°C chilled water temperature. Cold is produced at temperatures between −10 and +10 °C for a driving temperature in the range of 120–150 °C.     

基于多尺度匹配滤波和集成学习的眼底图像微脉瘤检测

针对微脉瘤的灰度分布特性,提出一种新的微脉瘤检测算法。首先通过多尺度匹配滤波筛选出候选微脉瘤病变点,并作为种子点利用区域生长技术分割出病变区域;然后提取病变区域特征向量;最终采用Adaboost神经网络集成分类器检测真实的微脉瘤病变。在公开的ROC数据集测试表明,所提方法检测的平均正确率达到40.92%,优于以往的双环滤波和形态学方法。     

基于FPGA的关键词识别系统实现

随着微电子技术的高速发展,基于片上系统SOC的关键词识别系统的研究已成为当前语音处理领域的研究热点和难点。运用Xilinx公司ViterxII Pro开发板作为硬件平台,结合ISE10.1集成开发环境,完成了语音帧输出、MFCC、VQ和HMM等子模块的设计;提出了一种语音帧压缩模块架构,有效实现了语音帧信息到VQ标号序列的压缩,实现了由语音帧压缩模块和HMM模块构建的FPGA关键词识别系统。仿真实验结果表明,该系统具有较高的识别率和实时性,为关键词识别系统的FPGA硬件电路的实现研究提供了实例。