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.     

轧机主传动电机励磁控制分析

在技术资料短缺的情况下，结合实际经验，绘制出进口轧机主传动电机励磁控制电路图，并进行了较为详细的分析。     

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)     

焦炉装煤逸散物控制实践

分析了焦炉装煤过程烟尘产生的原因，介绍了焦炉装煤逸散物控制的新方法，以及实施后的效果。     

非金属夹杂物对硬线盘条拉拔性能的影响及其工艺控制

分析了非金属夹杂物对硬线盘条拉拔性能的影响及其来源 ,通过考察分析冶炼、浇注生产工艺针对非金属夹杂物含量的影响 ,提出了避免或减少非金属夹杂物含量的工艺控制方法。     

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.     

非标压力机箱形主梁全约束优化设计

根据非标设备结构优化问题的特点,给出满足《钢结构设计规范》(GBJ17 88)规定的箱形主梁全约束优化设计方 法。将编制的内罚函数法优化程序应用于主梁的设计,计算结果表明,该优化方法可应用于实际设计。     

生烃化学动力学在川东北普光气田的应用

普光气田是四川盆地近期发现的规模最大、埋藏最深、资源丰度最高的气田。通过认识普光气田各个烃源岩层的贡献量、生烃关键期与构造演化的关系、油气成藏具体模式等，建立生烃化学动力学模型、标定参数，结合地区烃源岩参数和地史、热史资料，定量描述该地区的生烃过程及油裂解成气过程。认为：普光地区的主力烃源岩为下志留统泥岩；主要干酪根生油期为早二叠世末到早三叠世末期（距今286Ma至240Ma）；主要干酪根生气期为中三叠世（距今240Ma至230Ma）；主要气源是原油后期热裂解气，原油裂解成气的时间比较晚，主要油裂解成气期为早白垩世（距今144Ma至97．5Ma），从而决定了普光气田的成藏模式为“多期成藏，油气转化，晚期定位”。图2表3参33     

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.     

新城金矿采场落矿控制爆破技术

新城金矿为蚀变岩型金矿床,由于受地质构造影响,顶板稳定性较差,局部和较大面积的顶板冒落现象时有发生,为了解决采场顶板安全问题和提高落矿主要技术经济指标而进行了“上向水平分层尾砂胶结充填法采场控制爆破技术”的试验研究工作,试验达到了预期效果。