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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.
731

An Analysis of Fossil-free Alternatives for Swedish railway

Komuhendo, Martina, Zhai, Yuanjian January 2020 (has links)
The transport sector is a major contributor to the rise in global temperatures and emissions. The use of fossil fuel being one of the main drivers, most modes of transport are looking at alternatives to the limited and environmentally unsustainable fuels. Despite the railway sector being considered the more ‘green’ alternative mode of transport as compared to other modes like air, there exist more work that is required to make the railway sector as efficient and green as possible especially the significant percentage of the railway networks that are still non-electrified. These lines tend to be short, isolated and in some instances with seasonal traffic, hence there not being an urgent need to electrify. The cost of electrification is usually costly especially in terms of initial infrastructure development and alternatives are needed where the cost of electrification is not viable. The main objective of this report is to analyze the current fossil-free alternatives that are available or soon to be available on the market and determine which alternative is suitable for a specific non-electrified line considering factors such as cost, impact to the environment and the long-term strategy. As this is a complex analysis, the authors of this report will utilize the analytical hierarchical process (AHP) model to determine the most suitable choice for each line. The AHP model is one of the multicriteria methods developed to deconstruct complex situations into simple levels with the first level containing the goal: determining the viability of a fossil-free alternative that may be suitable for a particular railway line using the various criteria and sub-criteria. The results differed along the various railway lines with Fryksdalsbanan, Tjustbanan, HällnäsLycksele, Kinnekullebanan and Vaggerydsbanan having battery-operated trains as the optimal choice while the Mellerud-Bengtsfors, Stångådalsbanan, both Inlandsbanan (North and South), HalmstadNässjö, Bockabanan and Nässjö-Vetlanda favoring the hydrogen-fueled trains. In conclusion, both the battery-operated and hydrogen-fueled trains are viable options on the short, low-demand railway lines while the electric trains and diesel-fueled trains are expensive and environmentally unsuitable, respectively.
732

Evaluation of Overall Environmental Impacts of Alternatives for Emission Control Systems applied for Waste to Energy Process / Utvärdering av miljöpåverkan hos alternativa rökgas- och kondensatreningssystem för avfallsförbränning

Sundin, Camilla January 2017 (has links)
Vattenfall operates a cogeneration plant where household and industrial waste is incinerated to generate electricity and district heating. The waste incineration generates flue gases, and the energy in the hot flue gases is recovered by condensation. Both flue gases and the flue gas condensate are treated by emission control systems before being released into nature. The emission control system is planned to be updated with better technologies currently applied in Sweden. In this study, a comparison of the overall environmental impact of the current emission control system and the new system for emission control is performed. Vattenfall will perform a comparative life cycle assessment, LCA, of the two emission control systems. A part of the LCA is an inventory analysis. In this study, data required for the inventory analysis will be collected and quantified. The parameters considered are emissions to air and water, consumption of chemicals, produced solid residue, and water utilization. The objectives with the planned upgrade of the emission control system, which are evaluated in this study, are to obtain a cleaner condensate stream that can be reused in the system, to reach a higher tolerance of sulphur content in the fuel, and to reach a better reduction of emissions, for future stricter regulation. From the perspective of this study, the new system for emission control system seems to be the choice for emission control system with the least environmental impact. The results show that the reasons for upgrading the emission control system are met with the new system. The condensate is significantly cleaner with the new alternative emission control system than in the current one, the total amount of emissions decreases by 99,98 w%. The significantly smaller amount of emissions results in a condensate flow that can be reused in the system, which could save a considerable amount of raw water each year. The SO2 emissions are reduced by 99,5 w%, which show that a higher sulphur content in the fuel could be tolerated with the new emission control system. Furthermore, the total amount of emission content in the flue gas decreases with 61,9 w% with the new emission control system. The emission parameters that are deemed likely to be more strictly regulated in coming regulations, NOx and Hg, are both significantly reduced with the new emission control system. On the other hand, both the consumption of chemicals and the production of solid residue increases in the new emission control system, compared to the current one. These aspects are important drawbacks with the new system, and the environmental impact of these aspects needs to be further investigated in the planned LCA. / Vattenfall driver ett kraftvärmeverk där avfall från hushåll och industrier förbränns för att generera el och fjärrvärme. Avfallsförbränningen genererar rökgaser, och energin i rökgaserna utvinns genom kondensering. Rökgaserna och kondensatet renas från föroreningar innan de släpps ut i naturen. Systemet för rökgas- och kondensatrening ska uppdateras till nyare tekniker. I det här arbetet jämförs den totala miljöpåverkan av det nuvarande och det nya systemet för rökgas- och kondensatrening. Vattenfall kommer i framtiden att utföra en jämförande livscykelanalys av de två rökgas- och kondensatreningssystemen. En del i en livscykelanalys är en inventeringsanalys. Syftet med det här arbetet är att samla in och kvantifiera den data som behövs för inventeringsanalysen. Parametrarna som tas med i inventeringsanalysen är utsläpp till luft och vatten, kemikalieförbrukning, restprodukter samt vattenförbrukning. Målen med uppdateringen av rökgas- och kondensatreningssystemen är att erhålla ett renare kondensat som kan återanvändas i systemet, att kunna elda bränsle med en högre halt svavel och fortfarande hålla utsläppen under utsläppsgränserna, samt att få en bättre rening av föroreningar för att kunna möta framtida utsläppskrav. Målet med detta arbete är att utvärdera hur väl dessa aspekter möts i det nya systemet för rökgas- och kondensatrening. Utifrån de aspekter som utvärderats i denna studie verkar det nya systemet för rökgas- och kondensatrening ha en mindre miljöpåverkan än det nuvarande. Resultaten visar att alla målen med att uppdatera rökgas- och kondensatreningssystemet nås med det nya systemet. Kondensatet blir signifikant renare med det nya systemet jämfört med det nuvarande, den totala mängden föroreningar i kondensatet minskar med 99,98 vikts%. Det innebär att kondensatet kan återanvändas i systemet, och en betydande mängd råvatten kan sparas varje år. Utsläppen av SO2 minskar med 99,5 vikts%, vilket visar att en högre svavelhalt i bränslet skulle kunna tolereras. Vidare minskar den totala mängden föroreningar i rökgaserna med 61,9 vikts%. De föroreningsparametrar som bedöms bli mer strikt reglerade inom en snar framtid, NOx och Hg, reduceras signifikant med det nya systemet för rökgas- och kondensatrening. Däremot ökar både kemikalieförbrukningen och mängden producerad restprodukt. Ökningarna är betydande nackdelar för det nya systemet, och miljöpåverkan av detta bör undersökas vidare i den planerade livscykelanalysen.
733

Linking environmental impact assessment and green procurement in the construction sector : opportunities and perspectives

Uttam, Kedar January 2011 (has links)
The construction sector has been greatly responsible for environmental pollution and problems related to sustainability. Hence, there is a crucial need to improve the sector’s environmental performance. In terms of assessing the environmental impacts of the construction sector at project and strategic level, policy instruments such as project-based environmental impact assessment (EIA) and strategic environmental assessment (SEA) play an important role. Another policy instrument, namely, green procurement has started to gain attention in the construction sector. Green procurement is a process that involves the incorporation of environmental requirements during the procurement of services and products. However, discussions on green procurement are rarely seen during the impact assessment (EIA and SEA) phase. Moreover, the construction process is usually multi-tiered, involving several stakeholders with varied objectives, which often leads to challenges concerning the translation of information produced in the impact assessment phase into action (during the construction phase). Therefore, this thesis aimed at analysing the way through which EIA as well as green procurement can improve the coordination between planning and construction phases. The thesis is based on literature review and interviews. This study envisaged an inter-connected process for EIA and green procurement, and reviewed the state of the art to motivate the postulation of such an inter-connected process. In addition, this study also reviewed recent development within procurement contracts, and focused on partnering in the construction industry. The results indicated that it would be appropriate to introduce green procurement during the pre-decision phase of an EIA. Further, the thesis chose renewable energy as a parameter for green procurement, and explored the perspectives of various categories of stakeholders in the Swedish construction on the inter-link between impact assessment and green procurement. The perspectives of the interviewed stakeholders indicate that the inter-link is required. However, the interview results show that there is a tendency in the Swedish construction sector to adopt various commercially available environmental assessment and certification tools. Furthermore, the thesis has mapped directions for future research. Future study should focus on the establishment of mechanisms for inter-connecting impact assessment and green procurement. It should investigate how the inter-link could be facilitated by certification tools being adopted. The future research should also examine how the inter-link can be developed together with concerned stakeholders through partnering. / QC 20111207 / Improving the environmental performance of the construction sector through linking environmental impact assessment and green procurement
734

Prospective Life Cycle Assessment of an Electrochemical Hydrogenation Process Over a Nickel Foam Cathode / Prospektiv livscykelanalys av en elektrokemisk hydrogeneringsprocess över en nickelskumkatod

Appiah-Twum, Hanson January 2022 (has links)
The need for a safe and sustainable chemical industry has called for the development of emerging technologies with improved environmental performance. In this study, an emerging electrochemical hydrogenation process over Ni foam is being developed at the laboratory scale with an expectation of less environmental impacts than a conventional palladium on carbon hydrogenation process. To understand better the potential environmental performance of the process at the matured scale, a prospective life cycle assessment was conducted to identify environmental hotspots for early process improvement. There is no standardised method for prospective life cycle assessment, hence a methodological recommendation in conducting a prospective LCA was proposed through a literature review.  The proposed methodology consists of three steps which are a pre-inventory stage, an inventory stage, and a post-inventory stage. These steps have been connected to the ISO 14044 standard methodology for conducting an LCA where the pre-inventory stage relates to the goal and scope definition, the inventory stage to inventory analysis, and the post-inventory connected to both the inventory analysis, impact assessment, and interpretation stages of the ISO methodology. The proposed methodology was applied to the electrochemical hydrogenation process over nickel foam cathode where a three-case scenario (lab, worst- and best-case scenarios) was investigated to identify hotspots for early process improvement. The theoretical upscaled process had a better environmental performance compared to the lab process. The identified hotspots in the upscaled process (worst-case) include electricity process, evaporation process, and solvent recycling process for ecotoxicity (freshwater), human toxicity (cancer), human toxicity (non-cancer), climate change and resource use (minerals and metals) impact categories. The best-case scenario had its identified hotspots in the electricity process, solvent recycling process, and distillation process. This shows the importance of circularity, recycling, and lean manufacturing to the pillars of sustainability. Reducing resource consumption per unit product while increasing the recycling efficiency of process waste will be imperative towards ensuring a green chemical industry. Based on the results, a reduction of electricity demand for the process, utilisation of an alternative less energy-consuming processes, or cleaner energy sourcing could further improve the potential environmental performance of the process. Based on the quality of the data used, it is recommended that the outcome of the study be cautiously interpreted.
735

Assessing the environmental impacts of a tool rental service from Husqvarna using Life Cycle Assessment  Confirmation that the opposition is completed / Miljöpåverkansutredning av en verktygshyrningstjänst från Husqvarna med hjälp av livscykelanalys

Heiska, Mirjami January 2019 (has links)
To decouple ever-increasing production and the related environmental impacts, collaborative use of products and product-service-systems including rental services can help to intensify the use of products during their designed lifetimes. While these approaches present potential to decrease environmental impacts compared to traditional linear product sales, they need to be assessed with a holistic scope to avoid counterintuitive trade-offs. This study evaluates the potential environment impacts of Husqvarna’s tool rental service with a hypothetical case example from Stockholm, Sweden. The objectives are to analyse the potential environmental impacts of the rental service, to identify hotspots for improvement and to compare the potential impacts of the rental system to a sales alternative. The annual service of one electric chainsaw is analysed using Life Cycle Assessment (LCA) methodology with different user scenarios. The potential impacts are analysed for global warming potential, fossil and mineral resource scarcity, marine ecotoxicity and human carcinogenic and non-carcinogenic toxicity. The analysis for the rental system shows that user transport back-and-forth to the rental service is a key contributor to all the environmental impacts analysed, if done by private cars. The comparative results to sales business model indicate that while the rental service can help to reduce the potential impacts in mineral resource scarcity and toxicities due to the lower number of products needed, the user transport may outweigh the potential improvements in global warming potential and fossil resource scarcity, depending on the distances and modes of transport. Different scenarios illustrate that the results are however sensitive to the assumptions made. Based on the results, it can be recommended to optimally place the service close to the users and to take efforts to reduce user transports around the service, to reach the environmental potential of the service. The sensitivity analyses also indicate the importance for accounting detailed data for LCAs for product-service-systems and covering the service holistically in system boundaries. Further studies on user behaviour are suggested to reach more robust analyses on consumer services, to cover also potential rebound effects. / Gemensam konsumtion av produkter kan minska dess miljöpåverkan, sett över produktens livstid, genom intensifiering av produktanvändning och minskad nyproduktion. Även om detta koncept har potential att minska miljöpåverkan, jämfört med traditionell linjär produktförsäljning, måste det granskas på ett systematiskt sätt. Denna studie utvärderar den potentiella miljöpåverkan av ett verktygshyrningssystem av Husqvarna med ett hypotetiskt exempel från Stockholm, Sverige. Målen är att analysera den potentiella miljöpåverkan av hyrestjänsten, identifiera förbättringspunkter och jämföra de potentiella effekterna av hyressystemet med ett försäljningsalternativ. Miljöpåverkan av en motorsåg under ett år är analyserad genom livscykelanalysmetod med olika scenarier. Analysen för hyressystemet visar att den högsta miljöpåverkan kommer från transporten av användare fram och tillbaka till hyresdepån, om transporten är gjord med personbilar. Resultaten indikerar att hyrestjänsten kan bidra till att minska potentiella effekter av mineralresursbrist och toxicitet, jämfört med försäljningsmodellen, på grund av det lägre antal producerade produkter. Hyrestjänsten kan dock riskera att öka växthuseffekten och påverkan på fossilresursbrist, beroende på transportens längd och transportsätt. Olika scenarier illustrerar att resultaten är känsliga för andantagen. Resultaten visar att det kan rekommenderas att placera tjänsten optimalt nära användarna och att försöka minska användartransporten runt tjänsten för att nå tjänstens optimala miljöpotential. Känslighetsanalyserna indikerar också att detaljerade data och omfattande systemgränser är viktiga med LCA studier om produktrelaterade tjänster. Ytterligare studier om användarbeteende föreslås för att nå mer robusta analyser av konsumenttjänster, för att utvärdera även potentiella rekyl-effekter.
736

Life Cycle Assessment and comparison of the climate impact of structural members and floor systems constructed in concrete, steel and timber

Rask, Fredrik January 2019 (has links)
In this report the climate impact is determined for some basic structural elements made in steel,>mber and concrete. The aim is to compare the climate impact of these three building materials byquan>fying the emissions related to the produc>on and construc>on of some typical structures.The comparison comprise two parts, were one is the comparison of members in bending,compression and tension and the other part is the comparison of a couple of floor structures.The emissions are determined through a Life Cycle Assessment, LCA. The members are comparedwith respect to their load bearing resistance and the floor structures is compared per square meter.The mo>va>on for this inves>ga>on is that the construc>on industry is a large contributor to the totalamount of greenhouse gas emissions and in order to reduce these emissions new solu>ons andprac>ses must be adopted. A more thoughVul choice of the materials used in structures has thepoten>al of reducing the emissions.The method of determining the climate impact is based on first determining the material quan>>esfor all the inves>gated structures and then calcula>ng the amount of carbon dioxide equivalentsrelated to the produc>on of these materials with the help of a Life Cycle Assessment.The material quan>>es of the structural members is determined based on the load. The dimensionsof the cross sec>on is determined with respect to the required load resistance. The materialquan>>es of the floor structures is based on some exis>ng solu>ons from manufacturers.The study show that the >mber based design solu>ons almost always has a smaller climate impactand that the differences can be considerable. Members made in steel oZen result in very largeamount of greenhouse gas emissions but the sca[er in the results indicate that the origin of the steelhas great importance. Primary steel has a much larger impact as opposed to recycled steel.The comparison of the floor designs show that beyond the material choice itself, also the materialefficiency is important. The hollow core slab made in concrete is a very material efficient design andmay in some cases be on par with >mber based designs.The massive >mber floors made of Cross Laminated Timber, CLT, has a fairly large climate impactbecause of the sheer volume of material and may be on the same level as the floor made in concretefor some scenarios. There is however a wide range in the result based on whether the material istransported a long distance and depending on the choice of insula>on material. If these choices isop>mised, the emissions of the CLT floor is instead on a much lower level, closer to that of the otherlightweight floors inves>gated.The process of evalua>ng and comparing the material choices and structural designs form a lifecycleperspec>ve can be u>lised during the design in order to reduce the emissions. With a be[erknowledge of the climate impact of the design, be[er choices can be made in order to reduce theemissions.
737

Environmental assessment of municipal solid waste incinerator bottom ash in road constructions

Olsson, Susanna January 2005 (has links)
There are several incentives for using bottom ash from municipal solid waste incineration (MSWI bottom ash) as a construction material, such as for road construction. These incentives include decreased disposal of material on landfills and a reduced amount of raw material extracted for road building purposes. However, one of the main obstacles to utilising the material is uncertainties regarding its environmental properties. The overall objective of this thesis is to describe the potential environmental impacts of utilising MSWI bottom ash in constructions and to improve the tools for environmental assessments. An environmental systems analysis (ESA) approach based on a life cycle perspective was outlined and used in a case study, with the aim of describing the differences in resource use and emissions that can be expected if crushed rock in the sub-base of a road in the Stockholm region in Sweden were to be substituted by MSWI bottom ash. The whole life cycle of the road was taken into account and the alternative disposal of the bottom ash was included. It was found that the studied alternatives would cause different types of potential environmental impact; whereas the conventional alternative with only crushed rock in the road’s sub-base would lead to larger use of energy and natural resources, the alternative with MSWI bottom ash in the sub-base would lead to larger contaminant leaching. It was concluded that a life cycle approach is needed in order to include both resource use and emissions in the comparison between the two alternative scenarios. The leaching of metals turned out to be the most important environmental aspect for the comparison and in particular the difference in copper (Cu) leaching was shown to be large. However, a large amount of Cu may not pose an environmental threat if the Cu is strongly bound to dissolved organic carbon (DOC). In order to improve the basis for toxicity estimates and environmental risk assessments, and thereby provide better input values for ESAs, the speciation of Cu to DOC in MSWI bottom ash leachate was studied. It was found that Cu to a large extent was bound to DOC, which is consistent with previous research. The results also suggest that the hydrophilic fraction of the MSWI bottom ash DOC is important for Cu complexation and that the pH-dependence for Cu complexation to MSWI bottom ash DOC is smaller than for natural DOC. This implies that models calibrated for natural DOC may give inconsistent simulations of Cu-DOC complexation in MSWI bottom ash leachate. / QC 20101217
738

Strengthening Ecological Connectivity : An exploratory study on establishing ecologicalcorridors in Frösön, Sweden

Rhode, Sarah January 2022 (has links)
The growing demand for urban areas has been a driving force for extensive changes to landscape. Thisrequires more focus on finding a balance between promoting urban development, and conservingbiodiversity in urban areas. The Intergovernmental Science-Policy Platform on Biodiversity andEcosystem Services (“IPBES”) suggests encouraging sustainable urban planning, as well as“maintaining, and designing for, ecological connectivity in urban spaces”. Ecological connectivity canbe modelled based on circuit theory. Landscape can be depicted as a conductive surface and resistancecan be attributed to landscape types according to its permeability to the movement of a species.Frösön is a district in the growing municipality of Östersund, Sweden, where several developmentplans are intended. This study aimed to identify where structural ecological connectivity existed inFrösön. It also aimed to determine where connectivity was disturbed by urban development, andexplore the options available to strengthen connectivity through establishing new ecological corridors.Land cover data was analysed to identify the forest patches that were larger than 50 000m2, andresistance values were attributed per land cover type. Circuitscape was used to model the connectivitybetween the forest patches, revealing the connectivity across Frösön. The development plans wereassessed to determine where the developments overlapped existing corridors with high connectivityvalues between forest patches. New corridors (pathways connecting high connectivity valuesbetween forest patches) that could compensate for the impact by development plans on connectivityas well as strengthen connectivity throughout Frösön were proposed. The findings in this reportconcur with the IPBES that urban development can be sustainable while preserving biodiversity.Additionally, the inclusion of connectivity models in the environmental impact assessment (“EIA”)process for developments, enables proactive decision-making on the design and location ofdevelopments. Moreover, it encourages urban development and the preservation of landscapeconnectivity. This study will be valuable to environmentalists carrying out EIAs and specialists thatopine on environmental policy and/or legislation. / <p>2022-0604</p>
739

IMPACT OF PRECIPITATION CHARACTERISTICS IN NUTRIENT AND CARBON DELIVERY TO STREAMS IN ARTIFICIALLY DRAINED LANDSCAPES OF THE MIDWEST

Cuadra, Pilar E. 02 February 2010 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Although many studies have investigated the impact of tile drainage on nitrate and pesticide export from cropland to streams, little information is known about the primary hydrological controls of tile flow response to precipitation events and its impact on N, P and C transport in artificially drained landscapes of the US Midwest. This study investigated 1) the relationship between precipitation characteristics and tile flow response at a high temporal resolution during storms; 2) the relative importance of macropore and matrix flow in tile flow and in N, P and C transport to tile drains; and 3) the impact of storm characteristics in N, P and C fluxes/export rates. The study was conducted between April and June 2008, in an agricultural tile drained soybean field, representative of agro-ecosystems of the US Midwest near Indianapolis, IN. For the 8 storms analyzed, results showed that bulk precipitation amount was the best predictor of mean and maximum tile flow, time to peak and runoff ratio. The contribution of macropore flow to total flow increased with precipitation amount, representing between 11% and 50% of total drain flow, with peak contributions between 15% and 74% of flow. For large storms (> 6 cm rainfall), cations data indicated a dilution of groundwater with new water as discharge peaked. Although no clear indication of dilution was observed for smaller storms (< 4 cm rainfall), macropore flow still contributed between 11% and 17% of total flow. For large storms, the transport of dissolved organic carbon (DOC), total phosphorous (TP) and soluble reactive phosphorus (SRP) was found to be regulated mainly by macropore flow while nitrate transport was regulated mainly by matrix flow. For smaller storms, macropore flow dominated DOC and TP transport while SRP and nitrate transport was dominated by matrix flow. These results significantly increase our understanding of the hydrological functioning of tile drained fields and its interaction with N, P and C transport in spring, which is the time of the year during which most water and N losses from tile drains occur in the Midwest.
740

Ekoturismföretagens hantering av transportutmaningen : En kvalitativ studie om svenska ekoturismföretag och deras insatser för hållbar transport till och inom destinationer

Petkovic, Marko, Söderblom, Martin January 2021 (has links)
Syftet Syftet med denna studie är att ge en ökad förståelse försvenska ekoturismföretagens hantering av transportfrågor.Studien syftar vidare till att identifiera förändringsmönstergällande transport till och inom ekoturismdestinationer.  Frågeställningar ➢ På vilka sätt arbetar ekoturismföretag för att främja hållbartransport till och inom destinationerna? ➢ Vilka förändringar har skett inom ekoturismföretagenstransportplanering de senaste åren? Metod För att uppnå syftet och svara på frågeställningarna har vi valt attgenomföra empiriinsamlingen med hjälp av en kvalitativ metod. Detkvalitativa materialet utgörs av sex semistrukturerade intervjuer medsvenska ekoturismföretag.  Slutsatser Studiens resultat har visat att svenska ekoturismföretag intearrangerar transport för turisterna till destinationer, om detta inteefterfrågas. Turisterna uppmuntras att alltid välja de mestmiljövänliga transportalternativen till och inom destinationer. Lokalaaktörer är engagerade i arrangerandet av transport inomdestinationerna och efterfrågan på hållbara transporter har ökat.Svenska ekoturismdestinationers lokalisering orsakar attkollektivtrafiken har otillräckligt många åkturer till dessadestinationer, därtill blir kollektivtrafiken ett olämpligttransportalternativ för turisterna.

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