A parametric study of strength reduction factors for elasto-plastic oscillators

Strength reduction factors (SRFs) continue to play a key role in obtaining design forces from elastic design spectra (via response modification factors) in ductility-based earthquake-resistant design. Despite several years of sustained research efforts, it has not been conclusively shown how SRF for a given singledegree-of-freedom structural system depends on various source and site parameters. A parametric study is carried out here for the explicit dependence of SRF spectrum (describing variation of SRF with system period for a given ductility demand) on strong motion duration, earthquake magnitude, geological site conditions, and epicentral distance in case of (non-degrading) elasto-plastic oscillators. For this, scaled response spectra are considered for different combinations of earthquake magnitude, site conditions and epicentral distance, and SRF spectra are generated from 1274 accelerograms recorded in western USA after making those compatible with each of these spectra. It is shown that there is no clear and significant dependence of SRF spectrum on strong motion duration. Further, the parametric dependence on earthquake magnitude, site conditions, and epicentral distance broadly conforms to the trends reported by earlier investigations. In particular, this study confirms that the dependence of SRF spectra on earthquake magnitude should not be ignored. This paper has been contributed in honour of Professor R N Iyengar, Indian Institute of Science, on the occasion of his formal retirement.     

沁水煤田瓦斯含量与地质因素的关系

为确实做好瓦斯的洲报工作，研究了沁水煤田地质因素与瓦斯含量的关系，辩证地分析了瓦斯的赋存规律。     

Estimation of errors of hydrogen standard time scale preservation taking account of systematic frequency changes

Metrological characteristics of active hydrogen frequency standards are investigated on the basis of internal and external comparisons. The stability of random changes and drift of hydrogen frequency standards and also the potential capabilities of time scale preservation with effective consideration of systematic changes in their frequency are demonstrated. __________ Translated from Izmeritel’naya Tekhnika, No. 3. pp. 42–45, March, 2007.     

Assumptions and Consequences of Treating Providers in Therapy Studies as Fixed Versus Random Effects: Reply to Crits-Christoph, Tu, and Gallop (2003) and Serlin, Wampold, and Levin (2003).

In their comments on the authors' article (see record 2003-10163-009), R. C. Serlin, B. E. Wampold, and J. R. Levin (see record 2003-10163-011) and P. Crits-Christoph, X. Tu, and R. Gallop (see record 2003-10163-010) took issue with the authors' suggestion to evaluate therapy studies with nested providers with a fixed model approach. In this rejoinder, the authors' comment on Serlin et al's critique by showing that their arguments do not apply, are based on misconceptions about the purpose and nature of statistical inference, or are based on flawed reasoning. The authors also comment on Crits-Christoph et al's critique by showing that the proposed approach is very similar to, but less inclusive than, their own suggestion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

USL和USK系列振动筛防噪技术分析

为了改善筛分机械的使用环境，降低筛分机械的噪声，从噪声源入手，从内因和外因两个方面分析了筛分机噪声的形成原因。论述了USL和USK系列振动筛在降低噪声方面所采取的先进技术措施。     

Virtual Teams: Guide to Successful Implementation

The successful initiation and execution of a virtual team is gaining increasing attention in the design and construction community. From opportunities to integrate international and multidisciplinary teams to the opportunity to leverage the best resources in an organization on a given project, virtual teams can transform the concept of project planning and execution. However, potential barriers exist in several areas to the successful implementation of virtual teams. The needs of increased management emphasis, social and cultural understanding, and emphasis on common goals are only a few of the nontechnical factors that can turn successful virtual teaming into virtual frustration. When combined with traditional technical challenges including compatibility of systems, security, and the selection of appropriate technologies, the line between leveraging virtual technologies for enhanced solutions and introducing additional complications into the project process is one that can be easily crossed. This paper presents the findings of research that addresses the opportunities and potential barriers to successful virtual teams in the engineering, procurement, and construction industry. Combining results from current research, industry practices, and early results from nonconstruction industries, the research findings provide an initial path to successful virtual team implementation.     

USB技术在飞机外场设备测试中的应用

通用串行总线（USB）是近年来流行的一种新的微机总线接口标准，它可以实现较传统方式更有效、更经济、更多点的数据采集，详细介绍了利用USB技术实现飞机外场快速测试的方法。     

镍基耐海水腐蚀材料的研究概况

综述了镍基耐海水腐蚀材料的研究概况,阐述了Ni-Cu,Ni-Cr,Ni-Mo和Ni-Cr-Mo合金的耐腐蚀性能及其影响因素,展望了该材料研究未来的发展方向。     

徐深气田兴城开发区火山岩储层发育控制因素分析

利用岩心、薄片、分析化验、测井等资料,对徐深气田兴城开发区营城组一段火山岩储层进行了研究,结果表明:天然气主要产自溢流相的气孔流纹岩和爆发相的流纹质火山碎屑岩中,储集空间以气孔、粒间孔、斑晶溶孔、基质溶孔和构造裂缝为主.综合分析认为,储层的发育状况与构造活动、岩性岩相变化及成岩作用等因素密切相关.构造作用产生构造裂缝,形成有效的疏导体系;岩性岩相决定了原生孔隙的发育;成岩作用对原生孔缝进行了改造,其中压实、压溶、熔浆胶结和热液充填作用降低了储层的储渗能力,而溶解作用形成了大量次生溶蚀孔隙,使储层物性得到改善.不同岩性,其储层发育的主要控制因素不同.认识清楚储层发育的控制因素,对储层预测及今后气田的有效开发具有重要意义.     

Evaluation of capital cost data. part 7: Liquid waste disposal with emphasis on physical treatment

Capital cost correlations are given for oil-water separators, equalization basins, primary clarifiers, clarifiers and clarifier mechanisms, reverse osmosis unit, ultrafiltration units, gravity filters and miroscreens. Data are included for raw sewage, intermediate and recirculation pumping stations and for preliminary treatment (or bar screens, grit removal, overflow and bypass chamber and Parshall flume), for grit removal, comminution and gas stripping. The correlations are accurate to ± 30%, expressed in Canadian dollars and adjusted to a Marshall and Swift value of 1000. Details as to what components are included in the cost are given. Data are given for the labour and material costs to create a working process module. For inflation indices, a critique of the Engineering News Record, EPA small city, Marshall and Swift, Chemical Engineering and Southam inflation indices suggested that the Marshall and Swift index is most appropriate for the construction and process equipment studied here. Concerning the currency exchange, for the equipment and processes in this study, equipment costs the same whether expressed directly in US or Canadian dollars. To put the current data into perspective, several hundred sources of cost data were analyzed. The major correlations are compared, on a consistent basis, with current data.