Solar assisted cooling with sorption systems: status of the research in Mexico and Latin America

Solar refrigeration projects both national and international with sorption and other refrigeration systems have been developed in Mexico and other Latin American countries in the last 15 years. A review of the main projects, both for solar cooling and refrigeration and the results obtained are presented in this paper. A methodology where 19 solar technologies for cooling were identified is also presented. Although solar cooling is still not an economically viable technology, the advances made and the experience gained in the projects described and the improved systems envisaged, will make solar refrigeration systems play an important role in the future.     

Information systems effectiveness: research designs for causal inference

Abstract. This paper examines the capacity of the research designs of 37 empirical studies of information systems (IS) effectiveness to provide a basis for the development of theories about behaviour related to IS effectiveness. The power of each study to support causal inference was evaluated in terms of (a) its handling of the time dimension, (b) its ability to weigh differences and (c) its resistance to internal validity threats that pose alternative explanations for its reported findings. Of the reviewed studies, 29.7% could account for the time dimension, 32.4% employed a comparison group and 16.2% were not susceptible to any internal validity threats. Only 13.5% of the studies combined an accounting for the time dimension with the use of a comparison group. Of these, however, only 5.4% were also invulnerable to internal validity threats. The research designs of nearly 95% of these published studies were deficient in supporting causal inference. In those studies, suggestions that one variable was causally related to another variable could not be substantiated. Encouragement for the future capacity of IS effectiveness research to support causal inference was found in a trend towards the use of quasiexperimental designs. Recommendations are made regarding ways to increase the inferential capacity of research designs employed in the study of IS effectiveness.     

水泥膨胀珍珠岩砂浆的保温试验研究与应用

荆江分洪北闸加固工程２号护坦（斜面）混凝土的保温层采用了水泥膨胀珍珠岩砂浆，并对这种材料的保温效果进行了试验研究。试验表明：水泥膨胀珍珠岩砂浆降低最高温差，减小内表温差，缩小表温变幅和防止混凝土表面裂缝效果显著。在北闸２号护坦混凝土表面铺设１万平方米保温层，获得良好效果。     

信集闭系统进路数学模型及进路连锁表生成判据的研究

本文对信集闻系统中的长进路，进路及进路间的敌对关系等重要概念作了精确定义，并提出了进路的数学模型以及进路连锁表的生成判据。     

齿轮磨前滚刀的齿形研究

本文介绍了磨前滚刀滚切齿轮的最大根切量和磨后的渐开线长度计算,并建立了数学模型。为更加直观起见,还建立了模拟滚齿的数学模型。并在实验的基础上提出了参考标准。     

多级脉冲深穿透射孔技术

目前国内较先进的射孔工艺是增效射孔和三相流射孔,这2种射孔工艺均存在射孔深度和造缝深度浅的问题,尤其是对低渗油藏和纵向渗透率远大于横向渗透率的油藏,此造缝深度并不能满足油田生产的需要.介绍了一种新型的射孔技术,它是一种能进行深度射孔造缝的多级射孔技术,利用三级推进剂燃爆时产生峰值不连续的高温、高压气流,形成多级脉冲,多次冲击射孔孔眼前沿的裂缝,使其有效延伸至地层深处,从而较单独的射孔更能有效地增加油气产量.通过地面水泥靶的试验,证明了该射孔器的延缝功能和安全性;通过塘32等井的现场试验,证明该射孔技术对污染地层解堵有显著效果,可明显地降低地层破裂压力.     

引黄五座泵站火灾自动报警及联动控制系统

介绍了引黄工程五座泵站的火灾自动报警系统的组成及功能，对泵站的火灾探测系统、报警系统、联动控制系统、灭火系统、控制台等原理进行了详细说明，供同行参考借鉴。     

超径大块石二次爆破简便引爆装置的研究与应用

岩石爆破工程中,不可避免的会产生一些超径大块石,这些大块石一般质量都非常好,能满足砼对骨料质量的要求,但一般情况下都要进行二次爆破才能满足粒径要求。本文介绍了白石水库工程超径大块石二次爆破过程中工程技术人员经过技术研究和实验,利用废弃的导爆管与价格低廉的火雷管组合制成了技术上可行,操作上简单的新的引爆装置的成功经验。     

通过室内实验及同位素测井技术评价高分子聚合物驱油效果

2500万超高分聚合物室内驱油实验研究了聚合物分子量、浓度、粘度、聚用量、段塞组合等各项性能指标对驱油效果的影响。本文根据室内实验结果,在北一区断西注聚后期开展矿场试验,取得了较好的开发效果。试验前后对比,注入粘度明显增大,月含水上升速度得到有效控制,吸入剖面有了新的动用,有63.1%的油井出现了明显的二次受效特征,取得了显著的经济效益。同时对驱油效果进行系统分析。驱油效果表明:应用2500万超高分聚合物是进一步提高聚驱采收率的有效途径。