LED照明产品的全生命周期评价方法研究

生命周期评价(LCA)作为一种重要的环境管理工具,不仅能够对材料或产品全生命周期所涉及的环境问题进行评价,而且能为可持续发展决策提供依据,有利于促进产品、行业甚至整个产业链的行为更符合可持续发展的原则。但是目前国内还尚未有关于LED照明产品的生命周期评价。本文综述了生命周期评价方法在LED照明领域的应用,并提出我们的新思路,即将产品设计要素、经济成本要素及环境影响相结合的LED照明产品全生命周期评价方法。     

LED照明产品的全生命周期评价方法研究

生命周期评价（LCA）作为一种重要的环境管理工具,不仅能够对材料或产品全生命周期所涉及的环境问题进行评价,而且能为可持续发展决策提供依据,有利于促进产品、行业甚至整个产业链的行为更符合可持续发展的原则。但是目前国内还尚未有关于LED照明产品的生命周期评价。本文综述了生命周期评价方法在LED照明领域的应用,并提出我们的新思路,即将产品设计要素、经济成本要素及环境影响相结合的LED照明产品全生命周期评价方法。     

增材制造技术环境影响及其生命周期评价的研究进展

为了满足不同工业领域的需求,目前已有多种利用材料沉积方法进行增材制造(AM)的技术.其中,电弧增材制造(Wire and arc additivemanufacturing,WAAM)是一种发展迅速的增材制造技术,具有低能耗、低碳和低成本的优势,适合大型复杂金属零部件成型.虽然增材制造技术在材料、工艺、机械装置和系统集成方面发展快速,但对环境的影响仍未引起重视.由于不同的制造工艺所需的材料和能源差异较大,一般来讲,增材制造技术相对于传统工艺的总体优势不明显.因此,除了对增材制造技术本身以及工艺性能等方面进行研究外,还需要分析不同工艺方法对环境的影响.生命周期评价(LCA)是一种对产品、工艺或活动从原材料获取到最终处理全过程的重要环境管理评价工具,被越来越多地运用到不同材料制造工艺的分析与研究中.但LCA在增材制造领域中的应用和研究还较少,目前研究主要集中在粉末增材制造工艺的能源消耗和成本方面,在能源对环境影响以及生命周期数据清单方面还很少,尚未见到对电弧增材制造技术的环境影响及评价的报道.因此,有必要对这一领域进行更深入的研究.本文介绍了生命周期评价的定义和技术框架,并基于生命周期评价方法,从确定目标和范围、清单分析、环境评价和结果解释四个方面,评述了电弧增材制造部件在整个生命周期中所有物质和能量对环境影响的研究现状.同时将增材制造技术与不同的工艺方法进行了对比,分析了不同增材制造技术对环境影响的特点和进展.     

材料生命周期工程与材料生态设计的研究进展

材料生命周期工程以生态设计为主导,以满足性能需求、节约资源、保护环境为目标,将毒害组分替代、绿色工艺规划、清洁生产、资源循环等诸多技术与理论应用到产业链的各个环节,系统优化材料产品全生命周期的环境表现,是由材料科学、制造科学和环境科学深层次交叉而形成的国际重要科学研究前沿领域。回顾了国内外材料生命周期工程的发展与应用现状,通过分析其技术内涵,解释了生命周期工程与生态设计等关键技术要素的科学关联,并指明了生态设计是实现生命周期工程思想的关键技术问题。结合我国材料行业的发展现状,提出了适用于材料产品的生态设计理论框架与实施步骤,分别构建了基于性能-需求矩阵、资源耗竭模型、生命周期评价的材料性能、资源消耗与环境影响的量化分析方法,形成了可综合统筹不同设计指标、面向材料产品的生态设计评价方法,为生态环境材料的开发与应用提供了理论支撑。     

浅谈电子信息化产品环境评价的标准化

电子信息产业已经成为我国支柱产业,一般说来,电子信息产品是能耗产品,对环境影响很大,因此,对电子信息化产品环境评价的标准化研究显得尤为重要。本文基于国内外通用的电子信息化产品环境评价的相关概念和标准化研究现状,分别从产品所需原材料的筛选、产品生命周期的的延伸、能源节约等方面对电子信息化产品的环境评价标准进行陈述,希望能推动电子信息化产业的健康可持续发展。     

重质碳酸钙矿物填料的生命周期评价

无机非金属矿物填料降低成本在制品生产中具有重要的意义。生命周期评价方法已经成为对材料或产品进行环境表现分析的一种重要方法。本文选择了重质碳酸钙非金属矿物填料,介绍生产1t的重质碳酸钙的矿石开采、矿石运输和矿石加工阶段,采用生命周期方法,得到了重质碳酸钙的生命周期清单,并进行了评价。结果表明,石灰石开采过程对环境的影响最为严重。     

LED照明产品的生命周期评价方法及其清单分析方法的研究

生命周期评价(LCA)作为一种有效的环境管理工具,是实现人类社会可持续发展的重要手段,但是目前国内还尚未有关于LED照明产品的生命周期评价。本文综述了生命周期评价方法在LED照明领域的应用,并对其中的清单分析部分进行重点讨论。清单分析是LCA中继目标界定后的一步重要操作,工作量极大,数据的准确选择对LCA清单数据库的研究十分重要。     

产品包装生命周期分析与可持续发展探讨

论述了产品生命周期分析法(MET),是一种用于评估产品在其整个生命周期中,对环境影响的技术和方法.此方法以环境保护为核心,对包装进行环境影响的研究;它辅助设计实现其包装对环境的最小化影响,以促使人们生存的环境资源协调发展,最终实现社会、环境与生态的可持续发展.     

中国材料生命周期分析数据库开发及应用

生命周期分析作为广泛使用的环境管理工具,用于定量化评价产品系统整个生命周期内的潜在环境影响,其具体应用需要大量的不同层次、不同地区和不同技术水平的相关环境负荷数据和评价方法体系数据的支撑。在系列国家科技计划的支撑下,调研了典型材料生产的环境负荷数据,开展了中国材料环境数据库(SinoCenter)的研究,建立了中国材料生命周期分析数据库平台。数据库包含公用系统,典型材料(钢铁、建筑材料、有色金属、高分子材料、联接材料)等70多个数据集,近十万条环境负荷数据,并简要介绍了数据库的主要功能及数据库的技术和商业应用。     

生命周期评价在印刷与包装领域中的应用研究进展

阐述了生命周期评价基本涵义及其方法论,包括生命周期评价的定义、技术框架和实施方法等,并对印刷与包装领域产品或生产系统的生命周期评价典型案例进行分析与比较.最后对生命周期评价方法论的未来发展做出展望,并就印刷与包装产品与生产系统的生命周期评价方法的研究与推进提出建议.     

保税港区出口集运三级供应链博弈分析

基于随机需求,针对出口集运模型下一个国内供应商、一个国内分销商和一个国外零售商组成的三级供应链,运用博弈理论的逆向归纳法,定量比较分析有无保税港区情形下供应链上各成员的最优利润。结果表明：有保税港区后,供应链上成员达到了三方共赢;国外消费者的消费福利提高;供应商可获单位价值退税额与分销商可获单位价值利益的增加,有利于供应链三方利润的增加和消费者福利的提高。     

一类动力系统的稳定性及镇定

本文定义了一类新的动力系统-HCTD系统,利用矩阵迹的不等式理论研究了这类系统的稳定性,并给出了该系统稳定的充分必要条件。讨论了当Lyapunov方程的解P是HCTD阵时,动力系统稳定的充分条件。提出了用解矩阵迹的不等式设计动力系统镇定控制器的一种新方法。     

Diffraction Laser-Electronic Fourier Thickness Gage for Monitoring the Thickness of a Large Diameter Lens

The methodology of synthesizing a model for a diffraction laser-optical system for measuring the thickness of large diameter lenses within the framework of engineer-graph procedures for the design, manufacture, and study of a laser-electronic Fourier thickness gage is developed. Nine stages are identified for model synthesis based on successive-parallel sorting of models when considering statement of the problem in designing a laser-electronic Fourier thickness gage. The task of creating a fundamentally new method and provisions for measuring lens thickness is solved by means of an automatic diffraction-geometric-optical method for recording the space-frequency spectrum of the measuring aperture. Schematic analysis is performed and a functional optical scheme is constructed for a two-channel diffraction laser-optical system for measuring lens thickness. A measurement procedure is developed and the Fourier thickness gage developed is studied by experiment. __________ Translated from Izmeritel'naya Tekhnika, No. 10, pp. 30–35, October, 2005.     

Singularity-reduced integral equations for displacement discontinuities in three-dimensional linear elastic media

A systematic procedure is followed to develop singularity-reduced integral equations for displacement discontinuities in homogeneous linear elastic media. The procedure readily reproduces and generalizes, in a unified manner, various integral equations previously developed by other means, and it leads to a new stress relation from which a general weakly-singular, weak-form traction integral equation is established. An isolated discontinuity is treated first (including, as special cases, cracks and dislocations) after which singularity-reduced integral equations are obtained for cracks in a finite domain. The first step in the development is to regularize Somigliana's identity by utilizing a stress function for the stress fundamental solution to effect an integration by parts. The resulting integral equation is valid irrespective of the choice of stress function (as guaranteed by a certain ‘closure condition’ established for the integral operator), but certain particular forms of the stress function are introduced and discussed, including one which admits an interpretation as a ‘line discontinuity’. A singularity-reduced integral equation for the displacement gradients is then obtained by utilizing a relation between the stress function and the stress fundamental solution along with the closure condition. This construction does not rely upon a particular choice of stress function, and the final integral equation (which is a generalization of Mura's (1963) formula) has a kernel which is a simple function of the stress fundamental solution. From this relation, singularity-reduced integral equations for the stress and traction are easily obtained. The key step in the further development is the construction of an alternative stress integral equation for which a differential operator has been ‘factored out’ of the integral. This is accomplished by, in essence, establishing a stress function for the stress field induced by the discontinuity. A weak-form traction integral equation is then readily obtained and involves a kernel which is only weakly-singular. The nonuniqueness of this kernel is discussed in detail and it is shown that, at least in a certain sense, the kernel which is given is the simplest possible. The results for an isolated discontinuity are then adapted to treat cracks in a finite domain. In doing so, emphasis is given to the development of weakly-singular, weak-form displacement and traction integral equations since these form the basis of an effective numerical procedure for fracture analysis (Li et al., 1998), and such equations are presented for both elastostatics and elastodynamics. A noteworthy aspect of the development is that there is no need to introduce Cauchy principal value integrals much less Hadamard finite part integrals. Finally, the utility of the systematic procedure presented here for use in obtaining singularity-reduced integral equations for other unbounded media (viz. the half-space and bi-material) is indicated. This revised version was published online in July 2006 with corrections to the Cover Date.     

Bayesian calculation of cost optimal burn-in test durations for mixed exponential populations

The burn-in process is a part of the production process whereby manufactured products are operated for a short period of time before release. In this paper, a Bayesian method is developed for calculating the optimal burn-in duration for a batch of products whose life distribution is modeled as a mixture of two (denoted ‘strong’ and ‘weak’) exponential sub-populations. The criteria used is the minimization of a total expected cost function reflecting costs related to the burn-in process and to product failures throughout a warranty period. The expectation is taken with respect to the mixed exponential failure model and its parameters. The prior distribution for the parameters is constructed using a beta density for the mixture parameter and independent gamma densities for the failure rate parameters of the sub-populations. It is assumed that the optimal burn-in time is selected in advance and remains fixed throughout the burn-in process. When additional failure information is available prior to the burn-in process, the minimization of posterior total cost is used as the criteria for selecting the optimal burn-in time. Expressions for the joint posterior distribution and cost are provided for the case of both complete and truncated data. The method is illustrated with an example.     

An evolutionary algorithm for global optimization based on self-organizing maps

In this article, a new population-based algorithm for real-parameter global optimization is presented, which is denoted as self-organizing centroids optimization (SOC-opt). The proposed method uses a stochastic approach which is based on the sequential learning paradigm for self-organizing maps (SOMs). A modified version of the SOM is proposed where each cell contains an individual, which performs a search for a locally optimal solution and it is affected by the search for a global optimum. The movement of the individuals in the search space is based on a discrete-time dynamic filter, and various choices of this filter are possible to obtain different dynamics of the centroids. In this way, a general framework is defined where well-known algorithms represent a particular case. The proposed algorithm is validated through a set of problems, which include non-separable problems, and compared with state-of-the-art algorithms for global optimization.     

Permutation flow-shop scheduling problem to optimize a quadratic objective function

A flow-shop scheduling model enables appropriate sequencing for each job and for processing on a set of machines in compliance with identical processing orders. The objective is to achieve a feasible schedule for optimizing a given criterion. Permutation is a special setting of the model in which the processing order of the jobs on the machines is identical for each subsequent step of processing. This article addresses the permutation flow-shop scheduling problem to minimize the criterion of total weighted quadratic completion time. With a probability hypothesis, the asymptotic optimality of the weighted shortest processing time schedule under a consistency condition (WSPT-CC) is proven for sufficiently large-scale problems. However, the worst case performance ratio of the WSPT-CC schedule is the square of the number of machines in certain situations. A discrete differential evolution algorithm, where a new crossover method with multiple-point insertion is used to improve the final outcome, is presented to obtain high-quality solutions for moderate-scale problems. A sequence-independent lower bound is designed for pruning in a branch-and-bound algorithm for small-scale problems. A set of random experiments demonstrates the performance of the lower bound and the effectiveness of the proposed algorithms.     

Magneto stress analysis of a strip with a semi elliptical notch under uniform magnetic field

Two dimensional solutions of the magnetic field and magneto elastic stress are presented for a magnetic material of a thin strip with a semi-elliptical notch subjected to uniform magnetic field. The strip is a finite plate of a simply connected region. A linear constitutive equation is used for the stress analysis. According to the electro-magneto theory, only Maxwell stress is caused as a body force in a plate. Therefore, the magneto elastic stress is analyzed using Maxwell stress. In the present problem, as a result, the plane stress state does not arise, and the σ_z in the direction of the plate thickness and the shear deflection (anti-plane shear stress) arise for soft ferromagnetic material. The stress σ_z in the plate is strong compressive stress for a soft ferromagnetic material. A rational mapping function is used for the stress analysis, and the each solution is obtained as a closed form. No further assumption of the plane stress state that the plate is thin is made for the stress analysis, though Maxwell stress components are expressed by nonlinear terms. The rigorous boundary condition is completely satisfied without any linear assumptions on the boundary. The anti-plane shear stress causes Mode III stress intensity factor when the notch is a crack. Stress concentration values are investigated for a notch problem, of which expression is given. Figures of the anti-plane shear stress distribution, Mode III stress intensity factor, and stress concentration values are shown.     

Cubic equations of state for transport properties: An equation for the thermal conductivity of oxygen

A scheme for the development of equations for the transport properties in terms of pressure and temperature, so-called transport equations of state, is presented. The surfaces of transport properties and density as a function of pressure and temperature reveal similarities, which become even more evident when the residual transport property as a function of pressure and temperature is considered. Even the spinodals of transport and thermal properties coincide in the p, T plane, as can be shown mathematically and as was already empirically found for water and oxygen. Based on these similarities a cubic transport equation of state is evaluated for the residual thermal conductivity of oxygen. The new equation is only a little less accurate than the already established virial transport equation of state for oxygen. It is, however, much simpler and needs only a few parameters. The accuracy is still good enough for practical applications. The results demonstrate that cubic equations of state can describe transport properties and are a basis for generalized estimation methods for the transport properties of fluids.     

An application of the J-Q model for estimating cleavage stress in the brittle-to-ductile transition

A recent model was proposed by the authors to predict cleavage failure for steels based on a weak link mechanism and a crack tip stress field modified for planar constraint by the J – Q theory. The model uses the distribution of toughness results at a single temperature to predict a toughness distribution at a different temperature and/or geometry. In this model a material cleavage stress is needed to predict when the weak link fracture is triggered. This cleavage stress is a key input for the application of the model but it is not a property that is routinely measured and it is hence not available for most steel alloys. In this paper, a method to estimate the average value of the cleavage stress is presented, based on a characteristic of the model to predict cleavage failure. Examples of cleavage stress are given for several steels and these results are used to predict the toughness distributions for structural component models.