Failure analysis of three reconditioned rail car couplers

Three reconditioned rail car couplers, arbitrarily identified as couplers, failed during service due to cracking of the front face. The three couplers were reportedly upgraded by quenching and tempering to enhance strength and toughness. The objective of this investigation was to determine the mode of crack propagation and the root cause of the observed failures. Verl E. (Bud) Kahle, P.E., was a professional failure analyst for more than forty years. After receiving his Bachelor of Science degree in physical metallurgy from Washington State University 1957, Bud was employed by the General Electric Company at a facility in Hanford, Washington. He later was employed by the Aerojet General Corporation and eventually was head of the Southern Pacific Materials Science Laboratory in Sacramento. After retirement from Southern Pacific he owned and operated his own firm, Kahle Metallurgical Consulting Services, for fifteen years. He came to be known as “the man with the answers” to clients in a variety of industries. Bud was a Life Member of ASM International. Many of Bud’s clients remarked on the high quality of his failure analysis case histories and encouraged him to have them published. After Bud passed away in 1999, his wife, Suzanne, approached ASM International to see if the society would be interested in publishing any of his work. Mrs. Kahle was able to supply a large number of reports, which Bud had carefully archived over the years. Journal of Failure Analysis and Prevention Associate Editor Michael Stevenson read through the collected case histories, selected the ones to be included in this issue, and edited them for journal publication. ASM International wishes to thank Mrs. Kahle for providing these case histories for publication.     

满堂扣件式钢管脚手架应力传递规律试验研究

满堂扣件式钢管脚手架在混凝土工程模板施工中有着广泛的应用,具有拆装方便、周转次数多、经济效益显著等诸多优点。本文通过3×3跨的满堂式扣件钢管脚手架加载实验,在施加不同荷载的情况下,研究脚手架某一立杆扣件处的应力传递规律。采用数值模拟和现场监测等分析方法,分析在不同的荷载作用下,架体内部钢管立柱的应力传递规律,其结论和研究方法可为研究类似架体的受力性能提供借鉴和参考,同时为现场关键点监控和远程安全预警系统开发提供相应的理论依据。     

Analysis of frequency‐selective impedance loading of transmission lines for dual‐band couplers

This article proposes an analytical design methodology for dual‐band hybrid couplers and baluns structures for any arbitrary frequency ratio using a stub‐loaded transmission line. An analysis of changing the impedance behavior of the stub, is carried out for the two bands of operation, which along with a dispersive analysis, emphasizes certain conditions where the existing methodology is not applicable. In addition, an extra degree of freedom has been included to increase the solutions for a given frequency ratio, thus providing greater flexibility and feasibility of the proposed structure. The design methodology is experimentally validated with the design and fabrication of dual‐band branch‐line and rat‐race couplers for various commercial frequency bands. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE , 2011.     

扣件式钢管高支撑模板架的设计和施工

目前扣件式钢管高支撑模板架的设计基本上采用PKPM施工现场设施安全计算软件,在实际操作中,应进行一些设计补充,以满足安全施工的要求和可操作性的要求。文章介绍了一实际工程中高支撑架的设计及施工过程。     

光纤CAN环形网络的研究

由于光纤优良的抗电磁干扰能力、低损耗等特点,使光纤CAN网络在微波加热等复杂工业环境中得到越来越广泛的应用。在分析了CAN总线通信协议和光纤媒介拓扑结构的基础上,提出了一种基于LPC2292微控制器的光纤CAN环形网络的设计方案。采用光收发一体模块和2X2光分路器相结合的方式,设计了相应的接口电路和CAN控制器软件,并根据信号衰减和延时计算出网络可容纳的最大节点数。通过3个节点的光纤CAN环网实验,验证了该网络设计方案的有效性。     

梁模板扣件式钢管承重架的设计计算

以《建筑施工扣件式钢管脚手架安全技术规范》JGJ130 2001为依据,对空间高、跨度大、荷载重的大梁模板承重架进行了分析计算,给出了模板面板、方木、钢管和扣件的计算方法,对立杆稳定性计算的几种方法进行了对比。     

硅片V型槽光纤-波导耦合器

本文从硅晶体的结构说明V型槽形成的机理,该槽具有结晶学的平直、光滑、定位可控制在光刻精度的优点,经合理的方法较成功地实现了V型槽的制备,为光纤-波导的耦合提供较理想、稳定、低耗的器件。     

宽频带光电隔离跟随器

本文给出了一种频带宽度为500kHz的光电隔离跟随器,分析了这种隔离跟随器的传递函数、频带宽度和温度漂移,以及电路设计和实验结果.分析和实验表明,本隔离跟随器具有频带宽、非线性失真小、体积小和成本低的特点,可用于仪表放大器的后置隔离跟随.     

黑白染料胶片的现状和前景

黑白染料胶片是继彩色胶片之后发展起来的一种新型黑白胶片品种。本文概述了黑白染料胶片的优点 ,并简介了黑白染料胶片的油乳组成及成像机理。     

浅谈扣件式钢管脚手架工程施工安全控制措施

针对扣件式钢管脚手架施工安全问题,结合具体案例分析了扣件式钢管脚手架伤亡事故原因,提出了扣件式脚手架施工安全控制措施并作了具体阐述,以期减少和避免结构施工中的安全事故。