软岩隧道Ⅳ～Ⅵ级围岩相似材料正交试验研究

基于正交试验设计方法,将铁路隧道规范中围岩的重度、黏聚力和内摩擦角作为相似材料研究的目标参数,用黄土、石英砂、水泥、石膏和自来水为组料,较好地模拟了Ⅳ级、Ⅴ级和Ⅵ级围岩.此种相似材料具有容重低、性能稳定、易于购买、价格便宜和无毒等特点,是一种比较理想的地质力学模型相似材料.并通过试验确定了相似材料物理参数的主要影响因素并进行了敏感性分析,最终确定了不同级别围岩材料的合理配比.为软岩地区,特别是黄土地区的隧道工程中实验室模型试验研究奠定了基础.     

基于C#的船舶焊接物量定额系统研究

造船企业目前焊接物量统计和计划主要凭借经验来估计,导致焊材管理混乱,浪费严重,造船成本增加,针对这种情况研究出焊接物量定额系统,系统运用C#为开发工具,My SQL为后台数据库管理工具,实现了焊接物量定额的动态公式设定的功能,该动态公式针对不同船厂的焊接实际消耗情况来修正理论焊接物量,提高了系统的灵活性及实用性,为今后船厂的焊接管理和计划安排奠定基础,节约造船成本,从而达到精益造船的目标。     

SOM网络在铁路危险货物专用线风险评价中的应用

为合理确定铁路危险货物专用线的风险水平,提出了一种基于神经网络技术的风险评价模型.根据铁路危险货物专用线运营的特点及国家相关标准的要求,比较全面、系统地构建了铁路危险货物专用线及附属设施风险评价指标体系.为了弥补现有铁路危险货物专用线定量风险评价方法的不足,提出了基于自组织特征映射(SOM)网络的铁路危险货物专用线风险评价模型,并将训练后的模型应用于中石油某线路的风险评价,确定了该线路的风险等级.实例计算表明,该模型假设合理,计算结果符合实际情况.     

A Value-at-Risk (VAR) approach to routing rail hazmat shipments

Hazardous materials (hazmat) accidents are rare though the consequences could be disastrous. Given the possibility of low probability – high consequence event, a risk-averse routing hazmat shipment is necessary. We propose a value-at-risk (VaR) approach to route rail hazmat shipments, using the best train configuration, over a given railroad network with limited number of train services such that the transport risk as measured by VaR is minimized. Freight train derailment reports of the Federal Railroad Administration were analyzed to develop expressions that would incorporate characteristics of railroad accidents, and then to estimate the different inputs. The proposed methodology was used to study several problem instances generated using the realistic network of a railroad operator, and to demonstrate that it is possible to develop different routes for shipments depending on the risk preference of the decision maker.     

Computer simulation of impacts of a chlorine tanker truck accident

The aim of the study was to present the author’s original modelling programs of pollution dispersion in an urban environment. The programs outlined herein are based on a diagnostic model of air velocity field and Langrangian particle model. In both modelling programs author’s elements of mathematical modelling were applied. The models have been validated and verified. Geographic Information System (GIS) Idrisi Andes was applied in the pre-processing stage.The development of author’s original computer program and stages of hazardous material propagation modelling were discussed.The results of computations and analysis of pollution dispersion caused by a chlorine tanker truck collision and chlorine release into atmosphere were presented. It was simulated that the accident took place in the city of Bielsko-Biała, on a bypass in a built-up area causing leakage of 10 t of chlorine. The computer simulations conducted for two wind direction scenarios allow to conclude that the total area affected by the pollutant cloud with concentrations above threshold levels could be over 2 km², with 5000 lethally exposed people.     

公路工程建设领域改性沥青材料的运用

文章介绍了沥青的主要物理性质及具备的工程性能,阐述了几种常用聚合物改性沥青的组成成分、相容条件、功能和应用范围,并探讨了直接混溶法、胶乳法、母料法等改性沥青生产工法的优劣性及相关注意事项。     

人大复印转载高职院校教育类论文统计分析

以2007—2011年5年间人大复印资料高等教育所刊载的高职院校发表的文章为研究对象，对论文数量、作者地区分布、文献来源、高职院校文章排名和论文类别等信息进行了定量统计分析。     

高性能混凝土在京津城际轨道交通工程中的应用

通过高性能混凝土在京津城际轨道工程中的应用,介绍了高性能混凝土原材料的选择、配制、施工与检测过程,可为高性能混凝土在客运专线的应用提供参考。     

静水压力下功能梯度圆柱壳稳定性研究

文章研究了静水压力下功能梯度圆柱壳的稳定性特性.该文在Flügge理论的基础上,通过变换轴向波数,先后采用波动法和牛顿迭代法得到不同边界条件下FG圆柱壳的固有频率值.最后利用线性拟合方法得到水下FG圆柱壳的临界压力.在经过与各向同性圆柱壳的分析结果进行对比,验证了文中研究的有效性和正确性的基础上,讨论了水下FG圆柱壳的临界压力.通过算例,分析了材料组分、体积分数、边界条件、壳体尺寸等因素对水下FG圆柱壳临界压力的影响.     

水润滑材料研究进展

材料服役于水环境中,其摩擦磨损行为不仅与摩擦副材料本身的性质有关,还与载荷、速度、温度等因素相关,同时也与所处的环境有很大关系。本文重点阐述水环境对材料摩擦磨损性能的影响机制。在此基础上,进一步讨论材料在水溶液中的摩擦磨损行为。