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31.
为研究外包钢-混凝土组合梁与钢管混凝土柱连接节点的抗震性能,基于外包钢-混凝土组合梁与钢管混凝土柱连接节点低周反复荷载作用下的试验结果和有限元的模拟,分析了两类试验节点的滞回特性,提出外包钢-混凝土组合梁与钢管混凝土柱连接节点的三折线恢复力模型及其特征参数的取值范围,并给出恢复力模型表达式。结果表明,试件具有良好的耗能能力,建立的恢复力模型骨架曲线与试验值接近;有限元与试验所得的滞回曲线及骨架曲线在弹性阶段吻合较好,随着荷载的反复,两者之间的差异逐渐增大。 相似文献
32.
为简化防屈曲支撑的加工工艺,提高防屈曲支撑的初始刚度和在小变形下的耗能能力,基于现有防屈曲支撑在截面形式与构造方式上的特点,提出了一种新型钢铅组合防屈曲支撑并进行了构造设计。通过有限元数值模拟,分析了钢铅组合防屈曲支撑的耗能特性与效果,建立了恢复力简化模型,并根据理想弹塑性材料本构关系推导出滞回规则。通过对不同设计参数的理论分析和数值模拟,分析了钢铅屈服力比、铅剪切面长宽比、核心段宽厚比和耗能段长度等参数对防屈曲支撑滞回性能的影响。研究结果表明,钢铅组合防屈曲支撑能够提供较大的抗侧刚度,耗能效果良好,加工工艺简单,适合工程应用。 相似文献
33.
郑勇 《城市环境与城市生态》1998,(4)
本研究应用生命周期分析(lifecycleanalysis)的方法,对瑞典某金属表面处理工厂采用闭路循环工艺后的环境影响进行了分析。分析证明:闭路循环确可降低重金属对空气和水的污染,但增加了对不可再生能源的消耗,因而在采用该工艺时应特别关注能源问题.以期得到最好的环境效益。 相似文献
34.
废纸制浆造纸废水封闭循环处理工艺 总被引:1,自引:0,他引:1
本文介绍了废纸造纸制浆废水的特点、在零排放和废水封闭循环中遇到的问题以及解决措施,介绍了几种目前比较常用的废纸制浆连纸循环水处理工艺及其发展状况。 相似文献
35.
为了研究个体死亡引发反馈环断裂对安全知识积累和扩散的影响,采用元胞自动机方法,构建了多层次、多状态、多行为的安全知识积累和扩散演化模型。然后运用交替变量控制法进行仿真实验,获取605组数据,并对所得数据进行层次回归分析。研究结果表明:个体死亡会阻碍安全知识积累且会加剧个体间知识差异,同时事故率的增加会提高知识积累机会和个体死亡机会,产生复杂的双向对冲效应;替代者知识水平能够对安全知识积累和扩散产生较大的正向影响,并能削弱个体死亡的负向影响;事故见证者的增加也能够产生一定的正向影响。据此提出“数量型死亡悖论”,并指出促进安全知识积累和扩散的重点方向。 相似文献
36.
《International Journal of Sustainable Engineering》2013,6(4):323-329
The life cycle of electronic and electrical equipment has been ruthlessly shortened due to the rapid promotion of new products. Such a phenomenon has thereby resulted in serious environmental pollution and damages to the natural ecology. In order to reduce electronic wastes and increase recycling products, a manufacturing/remanufacturing simulation model was constructed through a series of inventory management policies. The model included the use of the traditional supply chain structures for the forward movement of goods to consumers, as well as a number of specialised operations required to perform reverse supply chain activities. Such a model took into account all the supply chain members such as the suppliers, manufacturers, logistics centres and customers at the same time. Finally, a case study on the application of the model was conducted. 相似文献
37.
The aim of this paper is to understand the temporal changes in planktonic populations and to highlight some important factors that control the biological functioning and evolution of a recently flooded reservoir, the Sep reservoir (Massif Central, France). To achieve this objective, a 1D vertical coupled physical–biological model was used and developed. It couples relevant physical processes (dispersion, advection and convection) with biological processes taking into account the complexity of interactions within the microbial food web, including the conventional grazing food chain with a microbial loop. 相似文献
38.
Tsiliyannis CA 《Waste management (New York, N.Y.)》2012,32(1):177-193
Dynamic annual flow models incorporating consumer discard and usage loss and featuring deterministic and stochastic end-of-cycle (EOC) return by the consumer are developed for reused or remanufactured products (multiple cycle products, MCPs), including fast and slow cycling, short and long-lived products. It is shown that internal flows (reuse and overall consumption) increase proportionally to the dimensionless internal cycle factor (ICF) which is related to environmental impact reduction factors. The combined reuse/recycle (or cycle) rate is shown capable for shortcut, albeit effective, monitoring of environmental performance in terms of waste production, virgin material extraction and manufacturing impacts of all MCPs, a task, which physical variables (lifetime, cycling frequency, mean or total number of return trips) and conventional rates, via which environmental policy has been officially implemented (e.g. recycling rate) cannot accomplish. The cycle rate is shown to be an increasing (hyperbolic) function of ICF. The impact of the stochastic EOC return characteristics on total reuse and consumption flows, as well as on eco-performance, is assessed: symmetric EOC return has a small, positive effect on performance compared to deterministic, while early shifted EOC return is more beneficial. In order to be efficient, environmental policy should set higher minimum reuse targets for higher trippage MCPs. The results may serve for monitoring, flow accounting and comparative eco-assessment of MCPs. They may be useful in identifying reachable and efficient reuse/recycle targets for consumer products and in planning return via appropriate labelling and digital coding for enhancing environmental performance, while satisfying consumer demand. 相似文献
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