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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Environmental issues with the remanufacturing industry

Lindahl, Mattias, Sundin, Erik, Östlin, Johan January 2006 (has links)
Researchers often regard remanufacturing as an environmentally beneficial end-of-life option. There have been, however, few environmental measurements performed in the area. The aim of this paper is to identify general environmental pros and cons with remanufacturing. This is done through the analysis of practical examples in remanufacturing industries. Life Cycle Assessment methodology has been used for the environmental validations. The first conclusion, based on the industrial cases and the literature review, is that remanufacturing is preferable from a material resource perspective when compared with manufacturing of new products. The second conclusion is that remanufacturing is preferable from a more overarching perspective for some of the investigated cases, but it is not possible to draw any general conclusions since the companies studied are few and benefits from remanufacturing are highly context-related.
32

Industrial Symbiosis in the Biofuel Industry : Quantification of the Environmental Performance and Identification of Synergies

Martin, Michael January 2013 (has links)
The production of biofuels has increased in recent years, to reduce the dependence on fossil fuels and mitigate climate change. However, current production practices are heavily criticized on their environmental sustainability. Life cycle assessments have therefore been used in policies and academic studies to assess the systems; with divergent results. In the coming years however, biofuel production practices must improve to meet strict environmental sustainability policies. The aims of the research presented in this thesis, are to explore and analyze concepts from industrial symbiosis (IS) to improve the efficiency and environmental performance of biofuel production and identify possible material and energy exchanges between biofuel producers and external industries. An exploration of potential material and energy exchanges resulted in a diverse set of possible exchanges. Many exchanges were identified between biofuel producers to make use of each other’s by-products. There is also large potential for exchanges with external industries, e.g. with the food, energy and chemical producing industries. As such, the biofuel industry and external industries have possibilities for potential collaboration and environmental performance improvements, though implementation of the exchanges may be influenced by many conditions. In order to analyze if concepts from IS can provide benefits to firms of an IS network, an approach was created which outlines how quantifications of IS networks can be produced using life cycle assessment literature for guidelines and methodological considerations. The approach offers methods for quantifying the environmental performance for firms of the IS network and an approach to distribute impacts and credits for the exchanges between firm, to test the assumed benefits for the firms of the IS network. Life cycle assessment, and the approach from this thesis, have been used to quantify the environmental performance of IS networks by building scenarios based on an example from an IS network of biofuel producers in Sweden. From the analyses, it has been found that exchanges of material and energy may offer environmental performance improvements for the IS network and for firms of the network. However, the results are dependent upon the methodological considerations of the assessments, including the reference system, functional unit and allocation methods, in addition to important processes such as the agricultural inputs for the system and energy systems employed. By using industrial symbiosis concepts, biofuel producers have possibilities to improve the environmental performance. This is done by making use of by-products and waste and diversifying their products, promoting a transition toward biorefinery systems and a bio-based economy for regional environmental sustainability. / Produktionen av biobränslen har ökat de senaste åren, vilket är ett steg mot klimateffektivare lösningar i transportsektorn, men biodrivmedlen har ifrågasatts med hänvisning till tveksamheter kring deras miljö- och energiprestanda. Lifecykelanalyser har därför använts inom akademiska studier och för policy för att utvärdera systemen, dock utan samstämmiga resultat. Under de kommande åren måste därför praxis för produktion av biobränslen förbättras för att kunna möta de strikta kraven i hållbarhetskriterier för biobränslen. Syftet med forskningen som presenteras i den här doktorsavhandlingen är att utforska och analysera koncept från området Industriell symbios (IS) och därigenom identifiera förbättringar för ökad effektivitet och miljöprestanda för biobränsleproduktion. Vidare är syftet att identifiera möjliga material- och energiutbyten mellan biobränsleproducenter och externa industrier. Potentiella material- och energiutbyten undersöktes, vilket resulterade förslag på flera olika typer av potentiella utbyten. Undersökningen visar på en potential för att använda biprodukter i en biobränsleprocess som råvara till en annan biobränsleframställning. Vidare identifierades en stor potential för utbyten med externa industrier, som till exempel matproducenter samt industrier för energi och kemikalier. Det är tydligt att det finns möjligheter för biobränsleproducenter och externa industrier att samarbeta och därmed ge möjlighet till förbättringar i miljöprestandan, dock kan en implementering av dessa utbyten påverkas av många olika förutsättningar. Avhandlingen presenterar även ett tillvägagångssätt för att visa hur kvantifiering av miljöprestanda inom ett nätverk för IS kan genomföras genom att använda riktlinjer och metodavvägningar från litteratur för livscykelanalys.  Detta tillvägagångssätt kan användas för att analysera om koncept från IS kan leda till fördelar för företagen i ett IS-nätverk. Tillvägsgångssättet ger möjlighet att kvantifiera miljöprestandan för företagen i IS-nätverket och ger dessutom vägledning för hur miljöpåverkan från utbytena kan distribueras mellan de olika företagen. Metoden utvecklades för att bland annat undersöka de förmodade fördelarna från IS för varje enskild aktör. Livscykelanalys i kombination med tillvägagångssättet ovan har använts för att kvantifiera miljöprestandan för IS-nätverk genom att konstruera scenarier. Scenarierna har baserats på ett exempel från ett IS-nätverk av biobränsleprocenter i Sverige. Analyserna visar att utbyten av material- och energi kan ge förbättringar i miljöprestanda. Resultaten är dock beroende av vilka metodavvägningar som gjorts, till exempel val av referenssystem, funktionell enhet och allokeringsmetoder. Vidare spelar viktiga processer som inputs från jordbruk och val av energisystem stor roll för resultatet. Metodavvägningar för utväderingen influerar även miljöpåverkan samt hur den fördelas mellan företagen i IS-nätverket. Dessutom kan den lokala miljöpåverkan öka medan den globala påverkan minskar. Sammanfattningsvis kan biobränsleproducenter, genom att använda koncept från industriell symbios, ges möjlighet att förbättra sin miljöprestanda. Detta kan ske genom att använda biprodukter och avfall samt genom att diversifiera sina produkter som ett första steg mot en övergång mot bioraffinaderier och en mer biobaserad ekonomi för regional hållbarhet.
33

Life Cycle Assessment : A Comparison Between a New Produced and a Remanufactured Rear Subframe

Holmberg, Pär, Argerich, Jennie January 2012 (has links)
Recycling is an important part of the automotive industry and this thesis was made to examine the environmental impact from the production of a new produced rear subframe compared to a remanufactured subframe. A life cycle assessment has been done to investigate the inputs and outputs of the processes surrounding the new production and remanufacturing. The emissions from the processes have been categorized into four environmental categories. Based on the categories a comparison have been made to evaluate the environmental impact and conclude the differences between the two processes.
34

Life Cycle Assessment Applied to 95 Representative U.S. Farms

Rutland, Christopher T. 2011 August 1900 (has links)
Since World War II, concern for the environmental impacts of human activities has grown. Agriculture plays a significant role in several impact categories including global warming. Governments, including the U.S., have recently begun or are considering the regulation of greenhouse gas (GHG) emission to mitigate the global warming effect. Because agriculture accounts for a large portion of anthropogenic greenhouse gas emissions, it is necessary to establish a baseline measure of the GHG emission of U.S. agriculture at the farm level. The objective of this research is to estimate the GHG emission levels for multicrop farms in the U.S. and identify the major sources of GHG emissions in their supply chains. To accomplish the objective, a partial life cycle assessment (LCA) methodology is used to establish a GHG baseline for the representative farms. LCA as defined by the International Organization for Standardization (ISO) includes four phases: goal and scope definition, inventory, impact assessment, and interpretation. It is a holistic approach that catalogues environmental impacts of all relevant processes at all stages of production, from raw material extraction to disposal. However, this study only catalogues impacts up to the farm gate. Partial LCAs are common in agriculture. Emissions of three GHGs, CO2, CH4, and N2O, are inventoried for 95 U.S. farms. The results are characterized using their 100-year global warming potentials into CO2 equivalents. The CO2 equivalents are then normalized over four functional units: enterprises, acres or head, harvest units, and pounds of production. The variation of GHG intensity between crops and farms is very large. However, it is clear that GHG intensity is affected by three characteristics: location, size, and irrigation practice. Crops grown in their associated regions tend to be more GHG efficient than those grown outside their associated regions. Also, crops grown on large farms tend to be more GHG efficient than the same crop grown on a small farm in the same area. Lastly, with the exceptions of cotton and soybeans, irrigated crops tend to be more GHG intensive than non-irrigated crops. These results combine to suggest that there may be a correlation between production efficiency and carbon efficiency.
35

Development of advanced mathematical programming methods for supply chain management

Kostin, Andrey 18 March 2013 (has links)
El objetivo es desarrollar una herramienta de apoyo a la toma de decisiones para la planificación estratégica de cadenas de suministro (CS). La tarea consiste en determinar el número, ubicación y capacidad de todos los nodos de la CS, su política de expansión, el transporte y la producción entre todos los nodos de la red. El problema se formula como un modelo de programación lineal entera mixta (MILP) que se resuelve utilizando diferentes herramientas. En primer lugar se desarrolló una estrategia de descomposición para acelerar el proceso de resolución En segundo, se utilizó el algoritmo de aproximación para resolver el problema MILP estocástico. Por último, el modelo multi-objetivo incorpora las soluciones de compromiso entre los aspectos económicos y ambientales. Todas las formulaciones se aplicaron al caso real de la industria de caña de azúcar en Argentina. El objetivo de las herramientas es ayudar a los responsables de planificación estratégica de las infraestructuras para la producción de productos químicos. / The aim of this thesis is to provide a decision-support tool for the strategic planning of supply chains (SCs). The task consists of determining the number, location and capacities of all SC facilities, their expansion policy, the transportation links that need to be established, and the production rates and flows of all materials involved in the network. The problem is formulated as a mixed-integer linear programming (MILP) model, which is solved using several mathematical programming tools. First, a decomposition strategy was developed to expedite the solving procedure. Second, the approximation algorithm was utilized to solve the stochastic version of the MILP. Finally, the multi-objective model was developed to incorporate the trade-off between economical and ecological issues. All formulations were applied to a real case based on the Argentinean sugarcane industry. The tools presented are intended to help policy-makers in the strategic planning of infrastructures for chemicals production.
36

Life Cycle Assessment of Electricity from Wave Power

Dahlsten, Hilda January 2009 (has links)
The use of ocean wave energy for electricity production has considerable potential, though it has proven to be difficult. A technology utilizing the heaving (up-and-down) motions of the waves was conceived at Uppsala University in the early 2000´s, and is being further developed for commercial use by Seabased Industry AB. The purpose of this master´s degree project was to increase the knowledge of the environmental performance of Seabased´s wave energy conversion concept and identifying possible areas of improvement. This was done by conducting a life cycle assessment (LCA) of a hypothetical prototype wave power plant. All flows of materials, energy, emissions and waste were calculated for all stages of a wave power plant´s life cycle. The potential environmental impact of these flows was then assessed, using the following impact categories: • Emission of greenhouse gases • Emission of ozone depleting gases • Emission of acidifying gases • Emission of gases that contribute to the forming of ground-level ozone • Emission of substances to water contributing to oxygen depletion (eutrophication) • Energy use (renewable and non-renewable) • Water use The methodology used was that prescribed by the ISO standard for Environmental Product Declarations (EPD) and further defined by the International EPD Programme.The potential environmental impact was calculated per kWh of wave power electricity delivered to the grid. The main result of the study is that the potential environmental impact of a wave power plant mainly stems from the manufacturing phase. In particular, the production of steel parts makes a large contribution to the overall results. Future wave power plant designs are expected to be considerably more material efficient, meaning that there are large possibilities to improve the environmental performance of this technology.
37

Engineering for sustainable development for bio-diesel production

Narayanan, Divya 15 May 2009 (has links)
Engineering for Sustainable Development (ESD) is an integrated systems approach, which aims at developing a balance between the requirements of the current stakeholders without compromising the ability of the future generations to meet their needs. This is a multi-criteria decision-making process that involves the identification of the most optimal sustainable process, which satisfies economic, ecological and social criteria as well as safety and health requirements. Certain difficulties are encountered when ESD is applied, such as ill-defined criteria, scarcity of information, lack of process-specific data, metrics, and the need to satisfy multiple decision makers. To overcome these difficulties, ESD can be broken down into three major steps, starting with the Life Cycle Assessment (LCA) of the process, followed by generation of non-dominating alternatives, and finally selecting the most sustainable process by employing an analytic hierarchical selection process. This methodology starts with the prioritization of the sustainability metrics (health and safety, economic, ecological and social components). The alternatives are then subjected to a pair-wise comparison with respect to each Sustainable Development (SD) indicator and prioritized depending on their performance. The SD indicator priority score and each individual alternative’s performance score together are used to determine the most sustainable alternative. The proposed methodology for ESD is applied for bio-diesel production in this thesis. The results obtained for bio-diesel production using the proposed methodology are similar to the alternatives that are considered to be economically and environmentally favorable by both researchers and commercial manufacturers; hence the proposed methodology can be considered to be accurate. The proposed methodology will also find wide range of application as it is flexible and can be used for the sustainable development of a number of systems similar to the bio-diesel production system; it is also user friendly and can be customized with ease. Due to these benefits, the proposed methodology can be considered to be a useful tool for decision making for sustainable development of chemical processes.
38

An Environmental and Policy Evaluation of Cellulosic Ethanol

Hurtado, Lisa Diane 2011 May 1900 (has links)
As the global demand for energy rises, there are significant efforts to find alternative energy sources. In the United States (US), these efforts are primarily motivated by a desire to increase energy security and reduce the potential impacts on climate change caused by carbon dioxide emissions from the burning of fossil fuels. Biofuels are considered a potential partial solution, which are being encouraged through public policy. Cellulosic ethanol is a biofuel that is required in increasing amounts over time as part of the Renewable Fuel Standards. Thus, researchers are exploring the environmental impacts of using this biofuel on a large scale. This dissertation research performed an environmental evaluation using the Life Cycle Assessment technique on Bioenergy Sorghum, a crop which was specifically produced as an energy crop, used in a conversion process (MixAlco version 1) that can produce cellulosic ethanol. Results indicate that the conversion process is highly optimized with minimal environmental concerns. Analysis of the crop production, however, demonstrate that further investigation is warranted regarding the depletion of natural resources and emissions from the fertilizers and pesticides/herbicides, due to large scale production of energy crops. A new policy is proposed to support the sustainable, environmentally responsible development of cellulosic ethanol in the US.
39

None

Lo, Wen-Cheng 25 July 2001 (has links)
Ecologist Tom Dale and Vernon Gill Carter Published a book ¡mTopsoil and Civilization¡n in 1955, There is a paragraph in the prolog¡G ¡uCivilized human always can temporarily control the environment mostly. Their main problem caused of the misconceiving that the temporary control can be forever. They misconceive that they are the ¡§dominator of the world¡¨, but don¡¦t realize the rule of the nature at all. Human no matter civilized or not, nevertheless, is the son not the master of nature. If they want to sustain and maintain the ecological environment, their behavior must follow the rule of nature. If they try to evade these rules, the consequence usually ruins the surrounding environment what nurture them. When the environment gets worst rapidly, their civilization declines too.¡v It seems to be a fate, like Morrie said in ¡mTuesday with Morrie¡n¡G¡uEvery one knows he will die, but nobody takes it as real.¡vHuman does not only treat his own life like this way, but also the environment what they survive and live in! From 1992, ¡¦Rome Club¡¦ published the book ¡mThe limit of growth¡n, the consciousness of environmental protection started to head up. Some issues like Ecology of commerce, Sustainable development, Land ethics, Deep ecology and Environmental economic came out one after one. Purely economic and efficient considering of design and production can¡¦t satisfy these kinds of demand. For this sake, International Standard Organization issued out the ISO-14000 series and accepted worldwide gradually. ISO-14040¡GLife Cycle Assessment¡Aevaluating the impact to the environment from material input, manufacturing, transportation, using, recycle, disposal, by other words--- ¡¥from the cradle to grave¡¦. LCA try to use quantitative concept to interpret the environmental impact or damage from human made product. It may provide environmental protection user a systematic thinking to distinguish which product is environmental amity product, which is not; also could be a stand for environment strategy. Applied on the production, it can be a good tool for ¡¥Green Design¡¦ thinking, to reduce the impact to the environment from every stage in production. This thesis is going to study the 6V4Ah Lead acid battery that used widely in the market. Quoting LCA¡¦s indications and SimaPro 4.0 software developed by Pre Consultants B.V. as the database and tools to evaluate the impact and damage to our environment. About the basic data bank, we adopt the local databank built by ITRI (Industrial Technology Research Institute) for years and the data included in SimaPro software. Those are Pre4, PreNL, BUWAL250 and IDEMAT96. Following the analysis procedures as Classification, Normalization, Evaluation by both impact orientation method --- Eco-indicator 95 method and damage orientation method --- Eco-indicator 99 method to evaluate this product¡¦s LCA study. Further more, look forward to provide a potential evaluation way to evaluate and compare to other various batteries.
40

Barriers for implementation of the Environmental Load Profile and other LCA-based tools

Brick, Karolina January 2008 (has links)
<p>The building sector is a vital part in the progress towards environmental sustainability, because of its high potential to decrease the environmental impact. However, the building industry remains one of the most critical industries for the adoption of environmental sustainability principles, because of several unique characteristics in terms of e.g. long-lived products and many stakeholders involved. Environmental assessment tools have an important role to play in implementing environmental sustainability in the building sector, as they provide a clear declaration of what are considered the key environmental considerations and also provide a way of communicating these issues. The Environmental Load Profile (ELP) is a Swedish Life Cycle Assessment (LCA) based tool for the built environment, originally developed as an instrument for evaluation of the environmental performance of Hammarby Sjöstad (HS), a new city district in Stockholm, Sweden. The ELP is facing implementation, aiming to be established as an instrument of common acceptance. Experiences and results from the ELP has revealed that it can be applied to give a comprehensive picture of the environmental performance of a city district, but also that the tool has a number of weaknesses and there is much to improve in the practical procedures for the use of the tool in environmental assessments.</p><p>This research project has the overall goal of making the ELP a stakeholder-accepted methodology for LCA-based assessment for the built environment. The overall goal includes two subgoals: (i) a research goal is to find an acceptable compromise in the design of the ELP tool between a natural science and technology based scientific accuracy and a social-science based acceptance of the tool and (ii) an implementation goal is to study and report experience from the use of the tool as developed today. The thesis consists of three papers: (i) the first is a study of two Swedish LCA-based tools for the built environment, which is based on comparative assessments using the ELP and EcoEffect (EE), (ii) the second is based on a questionnaire and interview study, in which we have investigated responses on LCA-based tools for the built environment among stakeholder representatives of Sweden’s building sector, with the purpose to identify barriers and opportunities for increased use of such tools and (iii) the third is based on case studies in HS using the ELP. We have identified the dominant environmental aspects in the ELP and also investigated the accuracy of the results. The study is completed with a development of a simplified version of the ELP, which also is applied in HS.</p><p>Findings show that despite applying the comparative parts of the ELP and EE on an equal basis (i.e. the object specific data), differences in results were found. The following factors give rise to the differences: (i) differences in material grouping and life expectancy for the construction materials used, (ii) diverse Life Cycle Inventory (LCI) data and (iii) different impact assessment. The required level of knowledge to compare, analyse and evaluate assessments made with the ELP and EE, is relatively high, which creates an educational barrier towards increased tool use. A number of other barriers that could mitigate a fruitful implementation of LCA-based tools in Sweden’s building sector have also been identified. We have found barriers between: (i) the current and the desired environmental work within the sector, (ii) the knowledge of and the use of LCA-based tools and (iii) the developers of the tools and the potential users. Other barriers further identified are especially connected to: (i) data (availability and credibility), (ii) costs, (iii) time, (iv) customer pressure, (v) knowledge and (vi) incentives. We have also identified the following opportunities for increased use of the tools: (i) different design of the tools for different actors and situations, (ii) combine LCA with LCC, (iii) involve environmental assessment in the implementation of the EU Directive on energy performance of buildings, (iv) develop reference values, (v) simplify input-data collection, (vi) improve environmental labelling and (vii) provide incentives. In the development of a simplified ELP we have noticed that the most important aspects contributing to the environmental load at a city district level (50 % of the total amount), covers 91-99 % of the total environmental load. The thesis shows that different simplifications of the ELP-tool are required for different purposes, actors and situations. A simplified version of the ELP, “ELP-light” was developed and applied in HS. In the development of ELP-light, we have used some of the identified opportunities and bridged some of the identified barriers.</p>

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