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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.
21

Cost-benefit analysis of microgenerators : an integrated appraisal perspective

Harajli, Hassan A. January 2009 (has links)
The UK domestic building sector accounts for a substantial amount of the final energy demand and greenhouse gas (GHG) emissions. To this extent, the sector can play an important role in GHG abatement and energy demand reduction, essential objectives of a more ‘sustainable energy system’. Microgeneration, or production of electricity or heat from small-scale sources, have been advocated by some, including the Supergen ‘Highly Distributed Power Systems Consortium’ to which this thesis contributes, as important means towards achieving these objectives. In this thesis, three assessed microgenerators; specifically a 600W microwind system, 2.1 kWp photovoltaic (PV) and building-integrated photovoltaic (BIPV) systems, and a 2.8m2 solar hot water (SHW) system have been analysed through an ‘integrated appraisal toolkit’ in order to assess their respective economic and financial performance in current UK context. A cost-benefit analysis (CBA) is applied, based on outputs and results from energy analysis and life-cycle assessment (LCA), and other tools such as financial appraisal, cost-effective analysis (CEA), and simple multi-attribute ranking technique (SMART) are also performed in order to asses how these systems perform on an individual household level or when compared to other energy technologies. The CBA, which included environmental impacts quantified through the LCA, obtained negative net present values (NPVs) for all the assessed microgenerators with the exception of microwind in a high-wind resourced ‘open’ area with lower end capital costs. The NPVs in the financial appraisal, which excluded environmental impacts, yielded relatively poorer results still. Only with the proposed feed-in tariffs would the systems all achieve positive NPVs. Given that the CBA included a substantial qualitative part, alternative tools, such as CEA and multi-criteria evaluation were applied (in brief) in order to place the assessed systems in the context of other energy generating sources in the UK, and to enable a more confident decision with respect to whether these systems should be advocated or rejected.
22

Life cycle analysis of biomass derived hydrogen and methane as fuel vectors, and a critical analysis of their future development in the UK

Patterson, Tim January 2013 (has links)
Concerns over environmental impacts and long term availability of liquid fossil fuels means that sourcing alternative, renewable transport fuels has increased in importance. To date, implemented approaches have concentrated on the production of liquid biofuels biodiesel and bioethanol from crops. Even though technology for implementation is readily available in the form of biogas production and upgrading, gaseous fuels have been largely overlooked in the UK. Research completed showed that if produced from indigenous crops using currently viable technology, it is energetically more favourable to produce gaseous fuels rather than biodiesel or bioethanol with gaseous fuels also delivering some emission benefits at end use. To date, the subsidy system supporting biofuel production has not functioned well. Research showed that if the subsidies approached the maximum allowable value, and when produced from waste materials, the production of gaseous fuels can be economic compared to liquid biofuels. Life cycle assessment has showed that utilising biomethane as a vehicle fuel could be an environmentally appropriate approach if the conventional use for biogas of combusting in a combined heat and power plant cannot utilise the majority of the excess heat produced. A two stage process to produce a hydrogen / methane blend was shown to be energetically favourable when utilising wheat feed, although hydrogen production was low. The process was not energetically favourable when food waste was utilised, indicating the importance of optimising process according to feedstock characteristics. Life cycle assessment of electrolytic hydrogen production using a range of energy sources found that electrolysis driven by renewable energy was a valid option for future deployment. However, given current feedstock availability, indigenous biofuel production, regardless of the fuel produced, could only make minor contributions to overall fuel requirements. As such, a range of fuel vectors, or a significantly greater commitment of land resources to fuel production, will be required in the future.
23

Integrated environmental assessment of industrial products

Sun, Mingbo, Mechanical & Manufacturing Engineering, Faculty of Engineering, UNSW January 2004 (has links)
Life Cycle Assessment (LCA) has been successfully used as an environmental assessment tool for the development of ecologically sustainable products. The application of LCA in the early design stage has been constrained by the requirement of large amounts of data and time for carrying out the assessment. In addition, the complexity of LCA causes further difficulties for product developers. In order to integrate the environmental assessment into the process of product development, this research proposes an integrated decision model for sustainable product development and a simplified LCA approach for the application in the early stage of product design. The main advantage of the proposed model is that it incorporates the environmental aspects of product development into the existing product development framework. It enables designers to strike a balance between the product???s environmental performance and other traditional design objectives. The simplified LCA approach is based on the concept and application of Environmental Impact Drivers. Material-based environmental impacts and Energy-based environmental impacts are used to predict the total environmental impact of a product. Two sets of impact drivers were developed accordingly. The Material-based Impact Drivers were identified by classifying materials into 16 groups according to the nature of the materials and their environmental performance. Energy-based Impact Drivers were developed for various energy sources in major industrial regions. Product LCA cases were used to verify the proposed methods. The results computed by the application of the impact drivers were compared with the results of full LCA studies. It is concluded that with the proposed approach, the product???s environmental performance can be assessed in a very short time and with very basic data input requirements and acceptable accuracy.
24

Fehlerrechnung in Oekobilanzen

Straubing 20 December 2001 (has links) (PDF)
No description available.
25

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.
26

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.
27

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.
28

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.
29

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.
30

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.

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