Modeling and analysis of automobile warranty data in presence of bias due to customer-rush near warranty expiration limit

Automobile users experiencing soft failures, often delay reporting of warranty claims till the coverage is about to expire. This results into a customer-rush near the warranty expiration limit leading to an occurrence of ‘spikes’ in warranty claims towards the end of warranty period and thereby introducing a bias into the dataset. At the same time, an occurrence of manufacturing/assembly defects in addition to the usage related failures, lead to ‘spikes’ in warranty claims near the beginning of the warranty period. When such data are used to capture the field failures for obtaining feedback on product quality/reliability, it may lead product or reliability engineers to potentially obtain a distorted picture of the reality. Although in reliability studies from automobile warranty data, several authors have addressed the well-recognized issues of incomplete and unclean nature of warranty data, the issue of ‘spikes’ has not received much attention. In this article, we address the issue of ‘spikes’ in the presence of the incomplete and unclean nature of warranty data and provide a methodology to arrive at component-level empirical hazard plots from such automobile warranty data.     

多回路输电线路上使用合成绝缘子有关问题的探讨

文章阐述了合成绝缘子耐雷性能的两面性;分析了在多雷区多回路输电线路上,杆塔比较高时,线路绝缘往往受大气过电压控制,由于合成绝缘子雷电冲击耐压水平较低,因此其使用受到限制,建议对有关规定提出修订。     

低合金含铬钢中稳定铬成分的工艺优化

针对低合金含铬钢中Cr成分不稳、回收率较低的状况，从温度制度、终点控制、助熔方法、转炉操作等方面采取了一系列措施进行工艺优化，使钢中铬的回收率从66．30％提高到90．65％，含铬钢的熔炼成分合格率达到98．49％，提高了钢板质量，使济钢生产的低合金含铬钢的各项性能等技术指标全部达到标准要求。     

降低供电系统线损提高电能利用率

本文通过对线损的概念、产生原因、如何计算进行阐述,从技术降损和管理线损两个方面提出了降低线损的措施,使线损率长期保持在4%以下,提高了电能利用率。     

2种NdFeB粉末的混炼研究

采用快淬法和雾化法制得的2种不同形貌的NdFeB磁粉,以尼龙12作粘结剂,研究了注射成形粘结磁体的混炼过程。分析了2种磁粉的形貌与粉末粒度及其分布,对混合料的粉末临界充填率、均匀度、流变特性的影响,以及混炼温度对磁性能的影响。     

淬火冷却速度对碳素钢显微组织的影响

在Gleeble2000热模拟实验机上对普通碳素钢Q235进行了不同温度的单道次变形实验，对变形后的试样采用三种不同的介质以不同冷却速度进行淬火，分别为水、-60℃的干冰酒精溶液和含50％NaCl的冰盐水。实验结果表明，不同冷却速度对淬火后的组织状态影响很大。在冰盐水中淬火，钢的淬透性较高，变形后原始奥氏体状态基本上得到保留。在干冰酒精中淬火钢的淬透性最差。     

Effect of Exogenous Rare Earths on Microbial Characteristics in Paddy Soil

Duetoincreasingcropyieldsandimprovingcropquality ,REammoniumhydrogencarbonatecomplexfertilizerwereappliedwidelyinsoils ,whichacceler atetheaccumulationofREinsoilsafteragriculturalapplication[1,2 ] .Previousstudieshavereportedaccu mulationofREsinsoilissignificantafter 3monthsofagriculturalapplication[3] ,andREhardlymigratedownward[4 ] .Itiscertaintythatagriculturalapplica tionofREcanresultREaccumulationinsoilandmayhaveaneffectonsoilmicrobialactivities .Soilmicro bialbiomassisamarkerofthemi…     

Identification and Validation of a Discrete Element Model for Concrete

The use of a three-dimensional discrete element method (DEM) is proposed to study concrete structures submitted to dynamic loading. The aim of this paper is to validate the model first in the quasistatic domain, and second in dynamic compression, at the sample scale. A particular growing technique is used to set a densely packed assembly of arbitrarily sized spherical particles interacting together, representing concrete. An important difference from classical DEMs where only contact interactions are considered, is the use of an interaction range. First, the correct identification of parameters of the DEM model to simulate elastic and nonlinear deformation including damage and rupture is made through quasistatic uniaxial compression and tension tests. The influence of the packing is shown. The model produces a quantitative match of strength and deformation characteristics of concrete in terms of Young’s modulus, Poisson’s coefficient, and compressive and tensile strengths. Then, its validity is extended through dynamic tests. The simulations exhibit complex macroscopic behaviors of concrete, such as strain softening, fractures that arise from extensive microcracking throughout the assembly, and strain rate dependency.     

Aging and the Detection of Contingency in Causal Learning.

Young and older participants' ability to detect negative, random, and positive response-outcome contingencies was evaluated using both contingency estimation and response rate adaptation tasks. Age differences in contingency estimation were consistently greater for negative than positive contingencies, and these differences, though still present, were smaller when response rate adaptation was used as the measure of contingency learning. Detecting causal contingency apparently becomes more difficult with age, especially when an oven numerical estimate of contingency must be provided and when the relationship between a causal event and an outcome is negative. A model that incorporates features of both associative and rule-based approaches to contingency learning (e.g., P. C. Price & J. F. Yates, 1995; D. R. Shanks, 1995) provides the best explanation for this pattern of findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

ТДГ3．15万kVA主变压器经济运行分析

根据电力变压器功率损耗的分析，找到ТДГ3．15万kVA2台主变压器的功率损耗与负荷率β的函数关系，并对该2台主变压器的经济运行进行了探讨，计算出了经济运行点。