立式燃煤蒸汽锅炉炉胆鼓包典型事故分析

本文针对一起立式燃煤蒸汽锅炉炉胆鼓包变形事故,通过现场检验及材料金相,分析产生的原因,提出相应的预防措施。     

桥头深厚软基处理中低强度桩的应用分析

结合某桥头段桥头深厚软基处理的工程实例,探讨了低强度桩处理桥头软基的机理和设计思路。     

新兴矿煤层冲击倾向性测定及分析

本文对新兴矿六采区58层煤岩进行冲击倾向性和相关物理力学参数的测定,可综合评判该煤层的冲击危险性,同时在矿井开采过程中,可依据相关参数的测定,采取必要的卸压、防冲措施,对实现煤层的安全高效开采具有重要意义。     

关于公路桥头搭板的试验与检测

桥头搭板是一端简支在桥台上,另一端搁置在桥头引道路基或者路面结构材料上的钢筋混凝土板。拟对高速公路通道桥两端桥头搭板进行了试验与研究,其中静载试验荷载作用下搭板底面对路基产生压力大小,以便判断是否有脱空即脱空位置,动载试验内容动载试验是对通道桥头搭板的动力特性以及汽车荷载作用下的动力响应进行试验研究,并评价行车舒适性。本文通过对高速公路桥头搭板静载和动载试验进行研究,对桥头搭板的结构形式的合理性,以及试验桥头的行车舒适性进行分析。     

江苏省城市化区域差异发展研究

受区域社会经济发展水平不平衡的影响,江苏省的城市化出现了苏南、苏中及苏北之间较大的差异性,这种差异性表现在城市数量、城市规模、城市化水平、城市现代化、城市地域特征等诸方面。由于苏南、苏中、苏北的城市化发展环境不同,因此三地区在城市化过程中应采取不同的发展模式。沿江地区是江苏省最发达的地区,完善的交通通信网络、良好的互通基础、密集而等级分明的城镇、政府的大力支持等良好的内外部环境使沿江城市带的构建成为可能,沿江城市带的建设可发挥城市的集合规模效益,推动江苏省的城市化进程,增强城市的辐射能力。     

浅析高速公路桥台台背质量影响因素及桥头跳车现象

本文结合高速公路施工从高填路基、桥台台背沉降、施工方法、填筑材料和结构原理上对高速公路桥台台背质量影响因素及桥头跳车现象进行原因分析,并提出减少病害防治措施。     

A new millennium and a new Journal for Injury Control and Safety Promotion

Youth violence continues to be a serious and too prevalent problem in the United States. There is increasingly compelling evidence that the exceptionally high levels of mortality are linked to access to guns by youth. There is also evidence that youth violence occurs in multiple forms and that these differing forms call for different prevention strategies. Some youth violence is situational, some is best understood within its relationship context, some occurs as part of a predatory criminal activity, and some seems to be the result of serious psychopathology. This paper provides a review of the current understanding of the epidemiology of youth violence in the United States, applies a developmental-ecological perspective to risk, reviews the empirical support for differing prevention approaches, and suggests practice, research, and policy implications of this knowledge base.     

CFG桩+泡沫混凝土解决软基桥头跳车的联合应用研究

为了减小路桥过渡段的差异沉降,缓解软土地区的桥头跳车问题,提出了一种采用CFG桩复合地基联合换填泡沫混凝土加固软基的方案。依托实际工程案例,采用有限元软件MIDAS GTS/NX建立了CFG桩复合地基工况模型与原始工况模型,检验了CFG桩复合地基的有效性,然后建立了CFG 桩联合台后换填泡沫混凝土方案的模型进行固结沉降分析,并验证了两者联合应用的优越性。研究结果显示：1）CFG桩复合地基对于软基的加固效果显著,其工期沉降比原始工况减少了18.32 cm;2）CFG桩复合地基加固软基时,台后换填泡沫混凝土使桥台与路面的台阶型差异沉降相较于台后普通路基填土工况减小了0.72 cm,对于桥头跳车问题的治理效果良好;3）模拟结果与工程实测沉降数据对比误差极小,说明了有限元模拟的可靠性。研究结果有效解决了常见的桥头跳车问题,方案具有更安全、环保、可靠的特点,可为软土地区的路桥过渡段工程提供一定的理论参考与借鉴。     

Asymptotic and Bootstrap techniques for testing the expected value of a fuzzy random variable

In this paper we will consider hypothesis-tests for the (fuzzy-valued) mean value of a fuzzy random variable in a population. For this purpose, we will make use of a generalized metric for fuzzy numbers, and we will develop an approach for normal fuzzy random variables, and two different approaches for the case of fuzzy random variables taking on a finite number of different values. A real-life example illustrates the use of the last two approaches. Finally, a comparison between the introduced techniques is developed by means of simulation studies leading to close inferential conclusions.Acknowledgements.The research in this paper has been partially supported by MCYT Grants BFM2002-01057 and BFM2001-3494. Their financial support is gratefully acknowledged. The authors are sincerely grateful to their colleague Gil González-Rodríguez for all his comments and suggestions in connection with this paper; his scientific support has been very valuable. The authors want also thank the referees of the first version of the paper because of their useful hints to improve it.     

Backyard Hog Production Efficiency: Evidence from the Philippines*

This article investigates the economic efficiency and the factors associated with efficiency for a sample of 126 hog producers in the Philippines. The input‐oriented efficiency indices are computed and bootstrapped using data envelopment analysis. Econometric analysis of the factors influencing the efficiency indices are conducted using the Tobit model. Fixed capital does not influence the efficiency scores, whereas labor does negatively influence the efficiency indices. On average, technical efficiency is low, an indication that most households are not using the most efficient technology. Scale efficiency is fairly high but constrained by lack of operating capital and managerial skills. Technical efficiency is constrained by lack of access to credit and limited experience in hog production.