Performance improvement potential of sensor embedded products in environmental supply chains

Environmental supply chain is a desirable alternative to traditional supply chain due to new and stricter environmental regulations by local governments and increasing consumer awareness towards environmental issues. The two most common types of environmental supply chains are reverse supply chains and closed-loop supply chains. In reverse or closed-loop supply chains, collected used products are subjected to one of four recovery options, viz., reuse, recycling, remanufacturing or disposal. Regardless of the chosen recovery option, all products are disassembled up to some level. However, there is a high level of uncertainty associated with the disassembly yield due to non-functional and/or missing components. Sensor embedded products (SEPs) is a viable approach to cope with this uncertainty since they involve sensors which can detect non-functional and/or missing components prior to disassembly. This study presents a quantitative assessment of the impact of SEPs on the various performance measures of a kanban-controlled disassembly line. First, separate design of experiments studies based on Orthogonal Arrays are carried out for conventional products and SEPs. Then, the results of paired t-tests comparing the two cases based on different performance measures are presented.     

Reverse logistics in Malaysia: Investigating the effect of green product design and resource commitment

Reverse logistics and green product design are green supply chain management practices that are being implemented to demonstrate firm's commitment to environmental sustainability. The generation of waste from electrical and electronic equipments prompts the viability of product recovery to salvage invested material and energy. Selection of various reverse logistics product disposition options relies on products’ residual value and the accessibility of reusable content for re-entry in forward supply chain. This study explores the effect of green product design and resource commitment on reverse logistics product disposition by employing empirical analysis on 89 returned mail survey received from ISO14001 certified electrical and electronic manufacturing firms in Malaysia. The results indicated that design for disassembly is necessary to harvest valuable inventories from every product disposition options except of disposal whereas design for environment and commitment of resources have slight influence on repair and disposal activities. As the evidences show that green product design and reverse logistics product disposition are interrelated, firms ought to undertake environmentally proactive approaches to generate benefits from resources that are undeservingly discarded as landfill waste.     

An optimization model for product returns using genetic algorithms and artificial immune system

Current environmental issues emerging in the world are reflected in the environmental legislation of several countries. Because environmental issues are important, industries actively seek ways in which to reduce their environmental footprint. One effective method is through the use of reverse logistics. Reverse logistics is the concept of reusing used products in order to reduce wastes and to increase an industry's environmental performance and resulting profits. Stock selection, transportation, centralized collection, data collection, refurbishing, and remanufacturing are some of the more commonly utilized reverse logistic operations. An effective reverse logistics network is essential for increasing the flow of goods from customers to producers. The objective of this paper is to develop a multi-echelon reverse logistics network for product returns to minimize the total reverse logistics cost, which consists of renting, inventory carrying, material handling, setup, and shipping costs. Industries need to give more attention to the task of collecting used products from customers and establishing collection facilities. In this study, a mixed integer non-linear programming (MINLP) model is developed to find out the number and location of initial collection points and centralized return centers required for an effective return and collection system, and also the maximum holding time (collection frequency) for aggregation of small volumes of returned products into large shipments. Two solution approaches, namely genetic algorithm and artificial immune system, are implemented and compared. The usefulness of the proposed model and algorithm are demonstrated via an illustrative example.     

基于生态足迹模型的重庆市可持续性动态测度与分析

重庆市作为长江流域上游唯一的直辖市,在促进城乡统筹改革和区域协调发展大局中具有重要战略地位,其可持续发展任重道远。运用生态足迹方法分析了重庆市2005年~2012年生态足迹的动态变化,并利用生态足迹和生态足迹强度指数等指标对其进行可持续性评估。结果表明:重庆市人均生态足迹由2005年的1.4527 hm2/cap增至2012年的1.9105 hm2/cap,人均生态赤字由0.9887hm2/cap上升至2012年的1.4224hm2/cap;人均生物资源足迹与人均能源生态足迹所占百分比平均为62.78%,37.22%;万元GDP生态足迹由2005年的1.33 hm2/万元降至2012年的0.56hm2/万元;生态足迹强度指数由2005年的3.13上升为2012年的3.91。结合重庆市加快5大功能区建设基础上提出人口控制、优化能源结构和提高环境保护标准、划定重庆市长江上游生态文明区生态红线、调整农业结构布局等方面政策建议。     

基于生态足迹的甘孜州生态安全动态研究

利用生态足迹评价模型计算甘孜州1995~2007年生态足迹,并分析甘孜州的生态安全状况。甘孜州人均生态足迹从1995年的1.480467hm2增加到2007年的1.766288 hm2,以耕地与草地为主;人均生态承载力从1995年的5.646667 hm2减少到2007年的5.328501 hm2,减幅较小,生态承载力结构具有不对称性,以林地与草地为主;人均生态盈余从1995年的4.1662hm2减少到2007年的3.562213hm2,林地人均生态盈余基本稳定在5.0 hm2左右,是甘孜州人均生态盈余的主要贡献者;生态压力指数在0.280852~0.350215波动,生态占用指数在0.528738~0.718585波动,生态协调性指数在1.875003~2.327831波动。结果表明甘孜州生态环境处于安全状态,社会经济发展与生态环境的协调性较差。     

Energy and carbon balances of wood cascade chains

In this study we analyze the energy and carbon balances of various cascade chains for recovered wood lumber. Post-recovery options include reuse as lumber, reprocessing as particleboard, pulping to form paper products, and burning for energy recovery. We compare energy and carbon balances of chains of cascaded products to the balances of products obtained from virgin wood fiber or from non-wood material. We describe and quantify several mechanisms through which cascading can affect the energy and carbon balances: direct cascade effects due to different properties and logistics of virgin and recovered materials, substitution effects due to the reduced demand for non-wood materials when wood is cascaded, and land use effects due to alternative possible land uses when less timber harvest is needed because of wood cascading. In some analyses we assume the forest is a limiting resource, and in others we include a fixed amount of forest land from which biomass can be harvested for use as material or biofuel. Energy and carbon balances take into account manufacturing processes, recovery and transportation energy, material recovery losses, and forest processes. We find that land use effects have the greatest impact on energy and carbon balances, followed by substitution effects, while direct cascade effects are relatively minor.     

Reverse logistics in the Brazilian construction industry

In Brazil most Construction and Demolition Waste (C&D waste) is not recycled. This situation is expected to change significantly, since new federal regulations oblige municipalities to create and implement sustainable C&D waste management plans which assign an important role to recycling activities. The recycling organizational network and its flows and components are fundamental to C&D waste recycling feasibility. Organizational networks, flows and components involve reverse logistics. The aim of this work is to introduce the concepts of reverse logistics and reverse distribution channel networks and to study the Brazilian C&D waste case.     

IDENTIFICATION OF AN OPTIMAL GROUNDWATER MANAGEMENT STRATEGY IN A CONTAMINATED AQUIFER1

A groundwater hydraulic management model is used to identify the optimal strategy for allocating limited fresh-water supplies and containing wastes in a hypothetical aquifer affected by brine contamination from surface disposal ponds. The present cost of pumping from a network of potential supply and interception wells is minimized over a five-year planning period, subject to a set of hydraulic, institutional, and legal constraints. Hydraulic constraints are formulated using linear systems theory to describe drawdown and velocity variables as linear functions of supply and interception well discharge decision variables. Successful validation of the optimal management strategy suggests that the model formulation can feasibly be applied to define management options for locally contaminated aquifer systems which are used to fulfill fresh-water demands.     

Electricity price and Southern California’s water supply options

This paper evaluates the impact of fluctuating electricity prices on the cost of five options to increase the water supply to urban areas in Southern California—new surface storage, water purchases, desalination, wastewater recycling, and conservation.We show that the price of electricity required to produce and transport water influences the cost of water supply options and may alter the decision makers economic ranking of these options. When electricity prices are low, water purchase is the cost effective option. When prices exceed US$ 86/MWh, conservation of electricity and water through installation of high efficiency clothes washers is the most effective option.     

流域比较视角的钱塘江与黑河流域水资源问题及对策研究——基于水足迹核算分析

产品贸易及水权交易使得水资源问题"跨流域化",不再单纯是流域内部管理问题。本文从流域比较视角出发,在区分蓝、绿、灰三种水足迹的基础上,应用水足迹模型,测算了两流域典型地区的水足迹,进行流域水资源问题对比分析,并分析了经济发展模式对流域水资源可持续性的影响。结果发现,杭州市经济用水中灰色水足迹占总量的90%,而张掖市经济用水中绿色水足迹占总量的60.8%,说明钱塘江流域水资源问题在于质,而黑河流域水资源问题在于量;经济发展模式中的产业结构、水资源开发效率、工业化路径等影响流域水资源可持续利用,同时基于GDP导向的流域间的水资源逆向配置,更加剧了流域水资源矛盾。最后根据流域对比结果提出治理措施,从而形成流域间协作的良性循环。     

皖南丘陵山区可持续发展的生态足迹分析——以池州市为例

生态足迹理论是一种定量测度区域可持续发展状态的有效方法。以皖南丘陵山区池州市为例，对其1996-2004年生态足迹和生态承载力进行了计算和分析。结果显示，池州市历年的人均生态足迹不断增加，9年时间增加了37．85％，而人均生态承载力却减少了5．49％。该地区历年人均生态足迹均出现赤字，而且呈增长的趋势；自然资源的利用效率不高以及自然资源供需的非均衡性增长导致生态赤字的出现和持续增长；目前池州市的发展模式已超出了自然生态系统的承载能力，处在不可持续的发展状态，并提出了相应的对策和措施。     

Urban channel adjustments in a management context: an Australian example

The impact of urbanization on stream channels has been investigated in a range of areas; the degree and extent of the channel adjustments have been demonstrated; and for a few areas these characteristics have recently been placed into a spatial context. A method of rapid field survey for depicting the channel network of urban areas in terms of near natural, adjusted, and channelized systems is illustrated for the urban area of Armidale NSW, for which Armidale Dumaresq Council had prepared a stormwater management plan. Such a survey could enable channel characteristics and adjustments, as well as water quantity and quality, to be included in the management plan. Possible options for management to address are suggested for each of the channel categories. A channel classification system of the kind suggested can provide a basic complement for the further development of the stormwater management plan, can afford a basis for specifying management alternatives, and can be helpful in demonstrating the options offered for community consultation.     

General equilibrium effects of a supply side GHG mitigation option under the Clean Development Mechanism

The Clean Development Mechanism (CDM) under the Kyoto Protocol to the United Nations Framework Convention on Climate Change is considered a key instrument to encourage developing countries' participation in the mitigation of global climate change. Reduction of greenhouse gas (GHG) emissions through the energy supply and demand side activities are the main options to be implemented under the CDM. This paper analyses the general equilibrium effects of a supply side GHG mitigation option-the substitution of thermal power with hydropower--in Thailand under the CDM. A static multi-sector general equilibrium model has been developed for the purpose of this study. The key finding of the study is that the substitution of electricity generation from thermal power plants with that from hydropower plants would increase economic welfare in Thailand. The supply side option would, however, adversely affect the gross domestic product (GDP) and the trade balance. The percentage changes in economic welfare, GDP and trade balance increase with the level of substitution and the price of certified emission reduction (CER) units.     

Siting and Routing Assessment for Solid Waste Management Under Uncertainty Using the Grey Mini-Max Regret Criterion

Solid waste management (SWM) is at the forefront of environmental concerns in the Lower Rio Grande Valley (LRGV), South Texas. The complexity in SWM drives area decision makers to look for innovative and forward-looking solutions to address various waste management options. In decision analysis, it is not uncommon for decision makers to go by an option that may minimize the maximum regret when some determinant factors are vague, ambiguous, or unclear. This article presents an innovative optimization model using the grey mini-max regret (GMMR) integer programming algorithm to outline an optimal regional coordination of solid waste routing and possible landfill/incinerator construction under an uncertain environment. The LRGV is an ideal location to apply the GMMR model for SWM planning because of its constant urban expansion, dwindling landfill space, and insufficient data availability signifying the planning uncertainty combined with vagueness in decision-making. The results give local decision makers hedged sets of options that consider various forms of systematic and event-based uncertainty. By extending the dimension of decision-making, this may lead to identifying a variety of beneficial solutions with efficient waste routing and facility siting for the time frame of 2005 through 2010 in LRGV. The results show the ability of the GMMR model to open insightful scenario planning that can handle situational and data-driven uncertainty in a way that was previously unavailable. Research findings also indicate that the large capital investment of incineration facilities makes such an option less competitive among municipal options for landfills. It is evident that the investment from a municipal standpoint is out of the question, but possible public–private partnerships may alleviate this obstacle.     

Modelling of the location of vehicle recycling facilities: A case study in Poland

The technical progress causes that increasing number of used devices presents a threat for environment, particularly in the rural areas. It can be prevented by organizing a proper system of waste disposal. Currently, the most important problem to solve is recycling of vehicles. The key element for the improvement of the functioning of the recycling network in Poland is to redesign the system so that it will allow for a reduction of the total cost related to the vehicle recycling. This paper presents a modelling approach that could be used to establish one important part of the reverse logistics (RL) network for end-of-life vehicles (ELVs) by defining the optimum locations for dismantling facilities. The proposed modelling approach is illustrated using Mazovia province in Poland as an example. The optimization criteria for the location of the elements of the recycling network are the components of the total cost of the ELV's recycling. Due to high complexity of the model a genetic algorithm has been adapted for solving the model and getting a good solution in a reasonable run time. The criteria of optimization was cost of the following processes: transportation, storage, and dismantling of ELVs. The results of simulation proved that the transportation costs of parts and materials may amount to about 70%, and that the cost of dismantling may exceed 25% of the total cost of recycling. The obtained results confirmed that genetic algorithm method can be used effectively to location the ELV's dismantling facilities. The effect of changing the location of processing facilities on the location of dismantling stations was also studied. The developed model is universal and may be used to determine the locations of different kinds of facilities organized in a reverse recycling network.     

Environmentally conscious manufacturing and product recovery (ECMPRO): A review of the state of the art

Gungor and Gupta [1999, Issues in environmentally conscious manufacturing and product recovery: a survey. Computers and Industrial Engineering, 36(4), 811–853] presented an important review of the development of research in Environmentally Conscious Manufacturing and Product Recovery (ECMPRO) and provided a state of the art survey of published work. However, that survey covered most papers published through 1998. Since then, a lot of activity has taken place in EMCPRO and several areas have become richer. Many new areas also have emerged. In this paper we primarily discuss the evolution of ECMPRO that has taken place in the last decade and discuss the new areas that have come into focus during this time. After presenting some background information, the paper systematically investigates the literature by classifying over 540 published references into four major categories, viz., environmentally conscious product design, reverse and closed-loop supply chains, remanufacturing, and disassembly. Finally, we conclude by summarizing the evolution of ECMPRO over the past decade together with the avenues for future research.     

WATER SUPPLY DILEMMAS OF GEOTHERMAL DEVELOPMENT IN THE IMPERIAL VALLEY OF CALIFORNIA1

Abstract: There are four known geothermal resource areas in the Imperial Valley that have a combined potential of over 4,000 megawatts of electrical energy for 25 years. Water resources available to support geothermal enerfy development are imprted Colorado River water, agricultural waste waters, Salton Sea water, and groundwater. In addtion, geothermal power plants can produce their own cooling water from steam condensate. Nevertheless, the relatively high water requirements of geothermal facilities along with a series of real and potential constraints may cause water supply dilemmas involving both the acquistion and use of cooling water. Important constraints are institutional policies, water supply costs, technical problems, and impacts upon the Salton Sea. These constranits and related dilemmas are examined in light of relevanty information on the valley's water resources, geothermal resources and energy technologies, cooling water requrements, and water supply options.     

US strategic minerals: Policy options

The USA is becoming increasingly dependent on key strategic metals (such as chrome, cobalt, manganese and platinum-group metals) from politically unstable regions of the world. This dependence is the result of an inconsistent and fragmented US non-fuel minerals policy. Neglect of the US minerals industry has led to a decline in US mineral production and processing capabilities. Options for a comprehensive US non-fuel minerals policy include increased domestic production; increased substitution and recycling; a domestic stockpiling programme; and diversification of, and ensured access to, foreign sources of supply. These four options are examined and recommendations are made for increased mineral surveys of public lands, a regulatory review, domestic production of strategic minerals, tax incentives, conservation, stockpiling, and a foreign policy that will ensure security of supply.     

Alternative energy balances for Bulgaria to mitigate climate change

Alternative energy balances aimed to mitigate greenhouse gas (GHG) emissions are developed as alternatives to the baseline energy balance. The section of mitigation options is based on the results of the GHG emission inventory for the 1987–1992 period. The energy sector is the main contributor to the total CO₂ emissions of Bulgaria. Stationary combustion for heat and electricity production as well as direct end-use combustion amounts to 80% of the total emissions. The parts of the energy network that could have the biggest influence on GHG emission reduction are identified. The potential effects of the following mitigation measures are discussed: rehabilitation of the combustion facilities currently in operation; repowering to natural gas; reduction of losses in thermal and electrical transmission and distribution networks; penetration of new combustion technologies; tariff structure improvement; renewable sources for electricity and heat production; wasteheat utilization; and supply of households with natural gas to substitute for electricity in space heating and cooking. The total available and the achievable potentials are estimated and the implementation barriers are discussed.

     

A MUNICIPAL WATER SUPPLY INVESTMENT PROBLEM IN RHODE ISLAND1

ABSTRACT: The traditional “requirements” approach to water system planning presumes perfectly inelastic demand and arbitrarily selects a fixed water requirement per capita per day as a planning target. Economists have often pointed out that such a policy leads to over-investment in water supply facilities; a superior approach would maximize some measure of net benefits incorporating price-sensitive demand. Using a dynamic programming model to depict an investment problem in Rhode Island, we find that ambiguities about how to incorporate price-sensitive demand into a decision framework may make such an approach as arbitrary as the requirements approach. Water conservation responses may be a function of other social parameters than water price; if so, variations in these social parameters should be regarded as economic alternatives to water supply investments.