End-of-life flows of multiple cycle consumer products

Explicit expressions for the end-of-life flows (EOL) of single and multiple cycle products (MCPs) are presented, including deterministic and stochastic EOL exit. The expressions are given in terms of the physical parameters (maximum lifetime, T, annual cycling frequency, f, number of cycles, N, and early discard or usage loss). EOL flows are also obtained for hi-tech products, which are rapidly renewed and thus may not attain steady state (e.g. electronic products, passenger cars). A ten-step recursive procedure for obtaining the dynamic EOL flow evolution is proposed. Applications of the EOL expressions and the ten-step procedure are given for electric household appliances, industrial machinery, tyres, vehicles and buildings, both for deterministic and stochastic EOL exit, (normal, Weibull and uniform exit distributions). The effect of the physical parameters and the stochastic characteristics on the EOL flow is investigated in the examples: it is shown that the EOL flow profile is determined primarily by the early discard dynamics; it also depends strongly on longevity and cycling frequency: higher lifetime or early discard/loss imply lower dynamic and steady state EOL flows. The stochastic exit shapes the overall EOL dynamic profile: Under symmetric EOL exit distribution, as the variance of the distribution increases (uniform to normal to deterministic) the initial EOL flow rise becomes steeper but the steady state or maximum EOL flow level is lower. The steepest EOL flow profile, featuring the highest steady state or maximum level, as well, corresponds to skew, earlier shifted EOL exit (e.g. Weibull). Since the EOL flow of returned products consists the sink of the reuse/remanufacturing cycle (sink to recycle) the results may be used in closed loop product lifecycle management operations for scheduling and sizing reverse manufacturing and for planning recycle logistics. Decoupling and quantification of both the full age EOL and of the early discard flows is useful, the latter being the target of enacted legislation aiming at increasing reuse.     

Numerical simulation of the large-scale malignant environmental pollution incident

With the development of economy, the expansion in industrial production resulted in the increase in the number of malignant environmental pollution incidents. The dispersion of toxic gaseous materials was chosen for study in detail, which took the ‘12.23’ Kaixian blowout accident in Chongqing as an example. This paper firstly reviewed the ‘12.23’ Kaixian blowout accident. Then, the physical boundary conditions including initial conditions were outlined to form an integrated mathematical problem. Thirdly, the blowout accident was simulated for a period of 5 h. In term of criteria for acute poisoning, simulation results were analyzed using the concentration slices that can serve for the decision-making. Finally, based on the analysis of simulation result, four important conclusions were put forward that can be used for the design of emergency evacuation routes.     

“安全科学技术”一级学科修订

介绍《学科分类与代码》国家标准中"安全科学技术"一级学科经过5年完成了制定,简述颁布16年后的实施及实践活动。近3年,经过多方研讨、论证,于2009年5月完成了"安全科学技术"一级学科的修订工作。通过该学科重新修订,进一步理顺了下属学科的名称、层次和隶属关系,增设多个(包括公共安全)二级学科和三级学科,使学科内容更加丰富、系统和完整。《学科分类与代码》国家标准GB/T13745—2009(代替GB/T13745—1992)的颁布实施,使"安全科学技术"一级学科在我国科教界的地位进一步巩固、发展和完善。     

地震灾情短信编码的初步研究

为了充分发挥地震灾情短信的信息负载功能,更全面地获取震后灾情信息,在对现有地震灾情短信代码介绍和分析的基础上,探讨了基于地震灾情现象的短信代码的设计原则和方法。确定了采用线分类法对地震灾情现象进行分类分级,并制定了分类分级的判断标志,然后,根据分类分级结果采用层次编码方式进行了短信代码的编制,设计了应用于不同对象的专业人员代码和公众代码。最后,阐述了如何使用这些地震灾情短信代码进行灾情上报及其对于地震应急工作的意义。     

3D Voronoi等效晶质模型在岩石破坏细观研究中的应用

基于3D Voronoi图提出一种能够反映岩石矿物晶粒结构的三维精细化建模方法,分析了晶粒排列均匀化程度及大小等微观结构的变化对模型宏观力学性质的影响程度,并进行了晶粒结构优化设计。通过模拟粉砂质板岩单轴压缩和巴西劈裂的破坏过程,以及与室内试验对比验证了其适用性,并从细观角度揭示了岩石的破坏机理。研究结果表明:通过裂纹生长速率大致可以表征室内试验中弹性变形、非弹性变形和峰值后宏观破坏阶段;岩样在单轴压缩和巴西劈裂破坏过程中以拉伸断裂为主,在宏观上表现为脆性断裂;岩样宏观断裂呈现沿晶和穿晶断裂的组合形态,弹性变形阶段裂纹的萌生和扩展以沿晶断裂为主,而穿晶断裂的扩展和贯通往往导致局部失稳,表现为非弹性变形阶段。     

Supplier codes of conduct: Company authorization of subcontractors

Companies continue to build greater sustainability and transparency in their supply chains to increase their business value and to respond to greater stakeholder pressures and expectations to increase sustainability and transparency. As company supply chains have grown and expanded, which presents increased challenges for building greater transparency, it is possible that the use of subcontractors in supply chains has also increased. The amount and impact of subcontracting conducted in supply chains may be of greater concern to certain companies and/or sectors than others, and it may have an important impact on their sustainability efforts. This article assesses the extent to which supplier codes of conduct apply to the use of subcontractors and include a requirement for suppliers to obtain prior company approval or authorization before subcontractors conduct work. Based on a review of more than 50 supplier codes of conduct, the companies that are highlighted in this article for including this requirement are primarily in the apparel/footwear, food, pharmaceuticals, and/or retail sectors. The article asserts that supplier codes of conduct that include requirements for suppliers to protect and safeguard confidential business information could be strengthened to further protect the company's products, integrity, and reputation/brand and increase its competitiveness and resilience by also including a requirement of prior approval or authorization of a supplier's use of subcontractors.     

基于ICEM-CFD的中子学力学耦合程序研制

目的针对反应堆工程分析中面临的中子学力学耦合这一问题,在同一软件框架下实现中子学力学多物理场计算。方法利用商业CAD前处理软件ICEM-CFD对堆芯几何进行网格剖分,开发基于有限元方法的中子学力学耦合计算程序,对同一堆芯网格划分进行中子学和力学计算。结果初步实现了基于同一软件框架下网格层面的中子学力学耦合计算,得到了中子学力学初步耦合的计算结果。结论通过基准例题对程序进行计算校验,该耦合程序计算能力是可信的。     

青海湖沉积物重金属分布及其潜在生态风险分析

青海湖是我国最大的闭口咸水湖.近年来随着工农业及旅游业的迅速发展,湖泊受人为活动影响不断增加,引起广大学者关注.为了深入了解青海湖表层沉积物中的重金属分布情况,在调查Zn、 Cu、 Pb、 Co、 Ni、 As、 Cd和Cr这8种重金属含量的基础上,对其赋存形态进行了分析,并对其进行来源解析和生态风险评价.结果表明：（1）青海湖表层沉积物重金属除ω（As）(13.21 mg·kg^-1)和ω（Cd）(0.21 mg·kg^-1)超出环境背景值1.13倍和1.53倍,其余6种重金属均不同程度低于环境背景值,从空间分布来看,除As外其他7种重金属元素空间分布特征极为相似,高值主要分布在湖泊西北部及151码头附近;（2）除Cd外其他7种重金属的主要存在形态为残渣态,而Cd主要以生物有效态形式存在,对水生生物具有较高的潜在生物毒性;（3）结合相关性分析和主成分分析,沉积物中Zn、 Cu、 Pb、 Co、 Ni、 Cd和Cr的来源以自然源为主,As的来源则受到农业生产等人为因素影响;（4）根据潜在风险分析结果,青海湖沉积物重金属整体处于轻微生态危害水平,但...     

Furfural residues from straw become complex fertilizer by addition method

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Sequential fractionation of reactive phosphorus in the sediment of a shallow eutrophic lake——Donghu Lake, China

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