Failure Analysis of Fuel System Assemblies

Fuel system assemblies used on recreational watercraft failed after a short time in service in a seawater environment. Examination of the assemblies revealed significant degradation of the polyacetal connectors of the wire subassemblies. Optical and microscopic evaluations indicated the complete loss of connector material implying decomposition of the resin, along with mud-cracking and a rough surface morphology signifying chemical attack. An elemental analysis performed on both an intact connector and degraded connector suggested a potential chemical agent in the form of zinc chloride. At elevated temperatures, concentrated zinc chloride solutions are known to decompose polyacetal resins. The source of the zinc chloride was established as corrosion products that resulted during the dezincification of the internal brass connector through exposure to saltwater in the application.     

浅埋地下建筑风冷热泵空调系统传热模型与试验研究

本文在浅埋地下建筑风冷热泵空调系统围护结构传热动态模拟的基础上，通过对南京市太园地下旅社围护结构传热的实时测试，验证动态传热模型及计算机模拟方法的可行性和正确性，为浅埋地下建筑风冷热泵空调系统的装机容量、节能指标和设计计算提供一定的理论依据。     

炼钢厂成本分析信息系统的开发设计

文章介绍了包钢炼钢厂生产管理信息系统中成本分析子系统的可行性分析以及具体的数据归集流程,详细介绍了该系统的开发环境以及该系统的模块和数据库的结构、功能及其具体的设计思想;简要介绍了Oraele Develop数据库开发应用的一些特点.     

漫谈钢铁企业用空分装置的流程选择

钢铁企业的氧气厂要深入了解本企业的用氧情况及周边市场的需要，据此确定拟新增空分装置的设计参数，选定最适宜的空分流程。探讨了空分流程选择时要考虑的几个方面。介绍了一种对空分装置的投资和长期运行费用之间进行经济性分析的定量计算公式，并得出了四点结论。     

Case Study of an Aerosol Explosion and a Method to Determine Explosion Temperatures

A failure analysis case study is presented for a two-piece aerosol containing tetrafluoroethane, commonly referred to as Refrigerant 134a. A gentleman was preparing to recharge the air conditioning system of an automobile when the bottom exploded off the aerosol container, propelling the body of the aerosol container like a rocket, which hit the man in the eye and blinded him in that eye. The aerosol was never connected to the air conditioner, therefore backpressure from the air conditioner (AC) compressor was ruled out as a cause for the explosion. The objective of the study was to determine why the aerosol exploded. Several recently developed test methods were used, including two types of heat-to-burst tests and a puncture chamber to measure the pressure-versus-temperature behavior of aerosols. More common test methods were also used, such as water bath pressure tests, hydro pressure burst tests, pneumatic pressure burst tests, hardness measurements, weight measurements, metallography, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and an accident scenario recreation. A semi-empirical correlation between the hardness and weights of the container bottoms was used to determine the explosion temperature and/or pressure. This semi-empirical correlation agrees in principle with an analysis of the explosion pressures using finite-element analysis (FEA). The root cause for the explosion was determined to be a lack of strength of the bottom of the two-piece aerosol coupled with heating the aerosol to temperatures significantly above room temperature.     

一些两段式煤气发生炉运行情况分析

两段式发生炉具有产生煤气热值较高，生产能力较大，稳定性较好等优点，目前在一些大中型企业运行良好。本文总结了一些两段炉操作运行情况，也指出了存在的一些问题，诸如煤气脱硫处理不当、停炉停产检修需调整以及应用计算机自动控制方面等问题有待于解决，最后提出一些建议。     

An investigation of the relation between the temperature dependences of the initial unbalance and the output signal of resistance strain sensor bridge circuits

The relation between the initial unbalance and the output signal of bridge circuits when acted upon simultaneously by the physical factor being measured and the temperature of the surroundings when the bridge is supplied from a voltage or current source is investigated. Analytic relations are obtained which explain the temperature dependence of the useful output voltage under external physical action. __________ Translated from Izmeritel’naya Tekhnika, No. 1, pp. 48–49, 2007.     

Extensions of LDA by PCA mixture model and class-wise features

Linear discriminant analysis (LDA) is a data discrimination technique that seeks transformation to maximize the ratio of the between-class scatter and the within-class scatter. While it has been successfully applied to several applications, it has two limitations, both concerning the underfitting problem. First, it fails to discriminate data with complex distributions since all data in each class are assumed to be distributed in the Gaussian manner. Second, it can lose class-wise information, since it produces only one transformation over the entire range of classes. We propose three extensions of LDA to overcome the above problems. The first extension overcomes the first problem by modelling the within-class scatter using a PCA mixture model that can represent more complex distribution. The second extension overcomes the second problem by taking different transformation for each class in order to provide class-wise features. The third extension combines these two modifications by representing each class in terms of the PCA mixture model and taking different transformation for each mixture component. It is shown that all our proposed extensions of LDA outperform LDA concerning classification errors for synthetic data classification, hand-written digit recognition, and alphabet recognition.     

65 Mn热轧带钢表面裂纹分析

分析了热轧带钢表面裂纹产生的原因，介绍了采取的工艺措施及其效果。