Incorporated probability that a fleet meets a given permissible value for the hull girder section modulus loss

The paper presents a study on the incorporated probability that a tanker fleet meets a given permissible value of hull girder strength loss. The analysis was based on a database of hull girder section modulus (HGSM) for as-gauged girth belts of tankers. It was found that its mean value is below 5% over the entire life span of the analyzed tanker fleet. The Weibull probabilistic distribution was found to best represent the time-varying HGSM loss. A method was developed for calculating the incorporated safety of a fleet. As an example, the IMO requirement for a maximum HGSM reduction of 10% relative to its required value was analyzed, accounting for time-variant HGSM loss and including a probabilistic model for coating longevity. The views expressed in the paper are those of the authors and not necessary those of ABS.     

On-road emissions from urban buses with SCR + Urea and EGR + DPF systems using diesel and biodiesel

Due to growing concerns about NO_x and particulate matter (PM) emissions from diesel engines, stricter regulations are being introduced requiring advanced emission control technology. In response the diesel industry has begun testing various emission control technologies and applying them. To assess vehicle renewal policies of bus companies, two exhaust after-treatment technologies are compared: the combination of a diesel particulate filter and an exhaust gas re-circulation system and the combination of a selective catalytic reduction and urea. On-board emission measurements were conducted under real-world driving conditions on a specific bus route in the city of Madrid.     

校园无线局域网的安全性研究

介绍了校园无线局域网的优势和问题所在.分析了WLAN(Wireless Local Area Network)IEEE802.11系列安全协议的工作方式,和各自的缺陷.提出了利用Linux内核空间下的Neffilter框架,动态加载IPSec处理模块的方法,构建了一个IPSec VPN网关,以解决无线网络的安全问题,同时也能实现在线实时的信息交换和共享.     

生态女性主义法哲学范畴研究——基于环境保护法视角

生态女性主义这一有关环境保护和妇女解放的重要思潮包含丰厚的法哲学内容,探究其法哲学范畴,具有理论与实践的双重意义。本文主要从女性与自然、妇女权益与绿色正义、法律女性与环境保护三对范畴研究了生态女性主义内蕴的法哲学含义。基于女性与自然的天然亲缘,我们亟需将妇女权益保护与绿色正义维护统一起来,发挥法律女性在环境保护中的特殊作用,为人与自然的和谐发展寻找到一条新的法治路径。     

Numerical Analysis of Thermal Distortion and Residual Stresses in H13 Steel Due to Vacuum Gas Quenching

IntroductionVacuumgasquenchinginvolvinghighpressuregasasacoolingmedium,is.anincreasinglypoPularheattreatffienttechniquefor1argesteeldieblocks,forexamPleHl3die.ItisconsideredessefltialtounderstandthentheeofthegasflowandtheinfiuencethishasontemPeratureprofilesandresultaflresidualstresseswithintheheattTeatedcomPonent.SimulatingthisprocessinvolvesthesimulationofgasflowinthefurnaceaswellasthesimulationofthethermalbehaviourofthecomPoneni.However,thereisnosinglecomPatersoftwarepackageavailabletot…     

油价上涨对我国汽车行业的影响分析

现阶段油价上涨的速度很快，油价的上涨对我国汽车消费的影响显而易见，它增加了现有消费者的使用成本，影响了潜在消费者的购买欲望，因而会对我国汽车行业产生深远的影响。企业应结合自己的实际，采取有利对策以适应油价上涨的不利影响。     

Capitalization of BRT network expansions effects into prices of non-expansion areas

A before and after hedonic model is used to determine the property value impacts on properties already served by the transit system caused by extensions to Bogotá’s bus rapid transit system. Asking prices of residential properties belonging to an intervention area (N = 1407 before, 1570 after) or a control area (N = 267 before, 732 after) and offered for sale between 2001 and 2006 are used to determine capitalization of the enhanced regional access provided by the extension. Properties offered during the year the extension was inaugurated and in subsequent years have asking prices that are between 13% and 14% higher than prices for properties in the control area, after adjusting for structural, neighborhood and regional accessibility characteristics of each property. Furthermore, the appreciation is similar for properties within 500 m and properties between 500 m and 1 km of the BRT.     

浅析交货期的牛鞭效应

1传统的牛鞭效应企业从原材料和零部件采购、运输、加工制造、分销直至最终送到顾客手中的这一过程被看成是一个环环相扣的链条 ,这就是供应链。从拓扑结构来看 ,供应链是一个网络 ,即自主或半自主的企业实体构成的网络 ,这些企业实体共同负责与一类或多类产品相关的采购、生产     

A probabilistic damage tolerance concept for welded joints. Part 1: data base and stochastic modelling

The present paper presents the necessary crack growth statistics and suggests stochastic models for a reliability analysis of the fatigue fracture of welded steel plate joints. The reliability levels are derived from extensive testing with fillet-welded joints for which the entire crack growth history has been measured, not only the final fatigue life. The statistics for the time to reach given crack depths are determined. Fracture-mechanics-derived crack growth curves are fitted to the measured experimental curves and the best fit defines the growth parameters involved for each test specimen. The derived statistics and distribution function for these parameters are used as variables in a Monte Carlo simulation (MCS). In addition a Markov model is developed as an alternative stochastic model. It is a Markov chain for which the discrete damage states are related to chosen crack depths in the material. This model works directly with the experimental time statistics. It is a “stochastic bulk approach” not involving any random variables or fracture mechanics modeling. Both models are fitted to the data base and scaled to in-service conditions. Both methods are compared and discussed. The aim is to provide data for the variables used in a MCS and to develop a Markov chain for fast reliability calculation, especially when predicting the most likely influence of numerous future inspections.