Temperature cycling and its effect on mechanical behaviours of highporosity chalks

Temperature history can have a significant effect on the strength of water-saturated chalk.In this study,hydrostatic stress cycles are applied to understand the mechanical response of chalk samples exposed to temperature cycling between each stress cycle,compared to the samples tested at a constant temperature.The total accumulated strain during a stress cycle and the irreversible strain are reported.Chalk samples from Kansas(USA)and Mons(Belgium),with different degrees of induration(i.e.amount of contact cementation),were used.The samples were saturated with equilibrated water(polar)and nonpolar Isopar H oil to quantify water weakening.All samples tested during 10 stress cycles with varying temperature(i.e.temperature cycled in between each stress cycle)accumulated more strain than those tested at constant temperatures.All the stress cycles were performed at 30℃.The two chalk types behaved similarly when saturated with Isopar H oil,but differently when saturated with water.When saturated with water,the stronger Kansas chalk accumulated more total strain and more irreversible strain within each stress cycle than the weaker Mons chalk.     

提高检测数据准确性 促进选钼生产稳定高效

本文从6个方面对选钼2个作业段的取样方式进行了校验,通过对检测数据的比对分析,找出了选钼2个作业段数据存在矛盾的原因,并针对原因采取了有效的措施,保证了检测数据的准确性,促进了选钼生产的稳定高效。     

移动探针测试技术的运用及测试结果剖析

主要讨论印刷电路板(PCB)移动探针测试中软件及检测中遇到特殊情况的处理,并对造成通短路现象的原因进行了分析,以达到保证PCB产品质量的目的。     

彩电机壳结构CAD(Ⅳ) 第四讲 TV-HCCS的表示模型和数据处理

彩色电视机机壳结构CAD系统要处理的数据量是相当大的。本文首先将需要处理的数据分类,然后阐述TV-HCCS表示模型的选取,最后介绍TV-HCCS采用的数据处理方法和相应的数据文件系统。     

钢筋混凝土非正常裂缝的产生原因及应对措施

根据钢筋混凝土结构中非正常裂缝的种类，分析了各种裂缝的产生原因，并有针对性地提出了应对措施，以保证建筑物和构件安全和稳定地工作。     

高速公路工程水土流失预测与分析实践

为验证《生产建设项目土壤流失量测算导则》(简称《导则》)对高速公路工程的适用性,运用《导则》对西南地区某高速公路工程建设进行水土流失预测,并与类比法测算结果进行对比。测算结果表明,路基工程区、附属设施区和弃渣场区是该项目土壤流失最多的区域,大部分土壤流失发生在施工期;采用《导则》与类比法得到的土壤流失量测算结果差异主要表现在工程开挖面区域,其余土壤流失类型下的测算结果差异较小;《导则》在线型工程水土流失预测中的运用稍显繁杂,而对于点状工程具有更强的实用性。     

Report on a new OED project: A study of the history of new words in the new OED

The study of the history of new words in theNewOED described in this paper was undertaken in 1986-87, and is based on the material then available. Since then, theNewOED has been finished, and PAT, the inquiry system developed at the University of Waterloo for the investigation of theNewOED data base, has been much altered and improved. Nevertheless, this report should prove useful in indicating the potentiality for analyzing the computerizedNewOED and some of the problems. This project is a study of the ways in which new words are created in English at various periods of time. A chronological dictionary 's created listing words introduced into the language over 50 year increments. These words are then classified by the processes used in forming them to show, in proportional terms, if certain processes are more common at some times than at others.H. M. Logan, Associate Professor, Department of English, University of Waterloo, Waterloo, Ontario, Canada, has written The Dialect of the Middle English Life of St. Katherine (Mouton, 1973), making use of the computer in a study of medieval dialectology. He has also written articles on computer stylistics and literary analysis inCHum, ALLC Journal, Language and Style, College Literature, and on the dictionary inDictionaries.     

Investigation into the morphological and mechanical properties of date palm fiber-reinforced epoxy structural composites

This study aims to examine the morphology and mechanical properties (tensile, flexural, and compressive) of epoxy composites reinforced with epoxy date palm leaves (EDPL), epoxy date palm branch (EDPB), and epoxy/hardener date palm core shell (EDPC) fibers (particle size <1 μm depend on the date palm fibers). A three-step technique was used to obtain the composites. The EDPL composites showed a maximum tensile strength of 3.45 MPa, while the EDPB composites showed maximum compressive and flexural rigidity of 9.46 and 5.55 MPa, respectively, owing to the good compatibility of fiber-matrix bonding. In this work, epoxy composites reinforced with date palm fibers (DPF) leaves, branches, and core shell were recycled using a cost-effective and easily reproducible three-step technique. EDPC fibers fabricated with 64.65% weight carbon fibers content demonstrated improved tensile strengths and stiffness properties. The three samples of palm date composites revealed mechanical properties that could be used to trial these fibers for manufacturing purposes, and to exploit their extraordinary mechanical properties shown in current results.     

Single-machine parallel-batching scheduling with family jobs to minimize weighted number of tardy jobs

We consider the problem of scheduling n jobs in batches on a single parallel-batching machine, where the jobs are partitioned into jobs families and the jobs in each family have the same due date. The objective is to minimize the weighted number of tardy jobs. We first devise an efficient pseudo-polynomial time and a fully polynomial time approximation scheme for the weighted problem. Then we present $O(n^2)$-time and $O(n\log n)$-time algorithms for the case where the jobs have the same weight and for the case where the jobs have the same processing time, respectively.     

车辆远程监控系统的设计与实现

文章提出了一种具有实时安全预警功能的车辆远程监控系统,包括车载数据采集端、手机客户端以及监控中心.汽车车载数据采集终端可实时采集到车辆的位置信息、速度和加速度信息并通过3G无线通信网络将这些数据发送到监控中心数据服务器.监控中心接收到所有车辆传来的数据,并将信息发送到用户车的手机客户端上,手机客户端通过本车的数据和周边车辆的数据计算出本车是否处于安全状态,如不安全手机客户端则会预警,提醒驾驶员采取措施避免事故的发生.