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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.
41

Integrated Life Cycle Analysis Approach (ILCA2) for Transportation Project and Program Development

Hameed, Faisal 04 May 2013 (has links)
Ensuring sustainability is important for balancing economic viability, the environment and the social system. Because transportation infrastructure projects have direct and indirect impacts associated with this balance, it is important for transportation agencies to consider sustainability and environmental impacts in transportation investment decision making.  These decisions typically occur during the planning and programming phase. Life Cycle Assessment (LCA) is an accepted method for quantifying life cycle environmental impacts. Within the transportation sector, current LCA practices are primarily limited to roadway pavements and the determination of greenhouse gas (GHG) emissions or a carbon footprint.  An urban roadway facility consists of several additional elements including sidewalks, street lights, traffic signals, lane striping and drainage which also have environmental impacts. In addition to the carbon footprint, roadway life cycle impacts include waste materials and storm water runoff. These life cycle impacts have associated costs. Life Cycle Cost Analysis (LCCA) is a commonly used methodology which analyzes life cycle costs of projects. However, this methodology does not include costs associated with environmental impacts. When integrated with LCA, the quantification of life cycle environmental impacts and costs for an urban roadway that includes construction, resurfacing and reconstruction as well as impacts related with managing the facility provides important information for making decisions that support sustainability related to transportation infrastructure. By establishing a reasonable life cycle time frame, representative elements, mostly homogeneous transportation facility types with representative cross sections, and accepted construction, maintenance and rehabilitation practices, a life cycle analysis approach which integrates LCA and LCCA is developed called Integrated Life Cycle Analysis Approach (ILCA2). Because decisions are made during the planning and programming stage, the approach is designed to use a standard cross section with standard materials for a transportation facility -- an urban roadway -- and three readily available project-specific inputs: length of roadway, number of travel lanes, and number of bicycle lanes.  The methodology quantifies life cycle environmental impacts for carbon footprint of the materials in CO₂ eq, quantity of wasted materials, quantity of storm water runoff and then estimates the costs associated with these impacts. This research demonstrated the use of ILCA2 for a case study section of an urban roadway and for a sample transportation State Transportation Improvement Program (STIP).  Using this approach to evaluate transportation projects provides several opportunities to enhance information used for decision making.  Life cycle environmental impact costs can represent a quarter of the total integrated life cycle costs of a transportation program. The case studies showed that the initial costs represent approximately half of life cycle costs for a single project and nearly a twentieth for the sample STIP. Environmental impact costs were higher than direct operation costs, energy costs, and resurfacing costs of an urban roadway.  Approximately 90% of material used in construction and rehabilitation of a roadway are removed in the rehabilitation and disposed of in landfills. This shows the potential for recovering, reclaiming, reusing and recycling these materials, potentially resulting in reduced life cycle environmental impacts.  Storm water runoff over the life cycle from the roadway was also substantial and the associated cost represents a significant portion of life cycle costs. When used over the life cycle of a transportation program, Low Impact Development (LID) strategies for roadways can result in economic benefits with higher cost savings than traditional drainage practices. When ILCA2 is applied to an individual project, decision makers have a better understanding of the expected costs and impacts associated with that project.  Applying ILCA2 to a program enables decision makers to evaluate the larger impacts of the transportation investments as well as consideration of programmatic changes to practices that support sustainability. / Ph. D.
42

Global cycle of gallium production, use and potential recycling.

Yaramadi Dehnavi, Pouya January 2013 (has links)
Life cycle analysis is an appropriate way to clear obscure facts about an element. Gallium is a critical element which is used in many technologies these days and therefore quantification of main global cycles of gallium, production, consumption and end of life products, also investigation about recycled gallium content and potential recycling possibilities are investigated in this paper. First a qualitative substance flow for gallium is designed similar to other metal cycles with regards to exclusive characteristics of gallium flows itself. USGS and World Mining Data are mainly used to get information about gallium production, main gallium consumptions and end of life products. Subsequently a quantitative model in STAN should unlock many uncertainties. Substance flow analysis and material flow analysis give a better understanding of unknown gallium flows with their uncertainties and meanwhile major applications, concentration of gallium in different products, waste flows, landfills and present recycling technologies are detailed. Consequently STAN model asserts that main gallium flows are primary gallium production and refined gallium production in production process, Integrated Circuit board fabrication, Light Emitting Diodes, Photovoltaic and recycled new scrap flow in manufacturing process. A significant amount of gallium is collected as stock in consumption process. Also current gallium recycling facilities are limited as recycling is not economically justified. Moreover main part of recycled gallium content is collected from new scrap which is formed through manufacturing process. Finally gallium consumption in Photovoltaic and Light Emitting Diodes industry increases rapidly and sustainability demand cost efficient methods for gallium recycling from solar cells, diodes and other end of life products.
43

Toward Sustainable Development: Quantifying Environmental Impact via Embodied Energy and CO2 Emissions for Geotechnical Construction

Shillaber, Craig Michael 16 March 2016 (has links)
With rising awareness that future generations may not have access to the resources and quality of life that exist today, sustainable development has become a priority within civil engineering. One important component of sustainable development is environmental stewardship, which concerns both the resources taken from the environment, and the wastes and byproducts emitted to the environment. To facilitate more sustainable development, environmental accounting is necessary within civil and geotechnical engineering design and construction. Historically, geotechnical practice has focused on maximizing design performance while minimizing monetary costs, and well established methods exist for quantifying these factors. Quantitative consideration of environmental consequences has seldom played a large role in geotechnical design and construction, and clear guidelines and a methodology for such an assessment are not available within the geotechnical profession. Therefore, this research has focused on establishing a method for quantitative streamlined environmental Life Cycle Analysis of energy and carbon dioxide (CO2) emissions for geotechnical ground improvement works, known as the Streamlined Energy and Emissions Assessment Model (SEEAM). The boundaries for the SEEAM extend from raw material extraction through the completion of construction, including the energy and CO2 emissions associated with construction materials, construction site operations, and the transportation of construction materials and wastes. The methodology relies on energy and CO2 emissions coefficients, which represent typical industry average values and not necessarily the specific processes contributing to a project. Therefore, there is uncertainty in SEEAM analyses, which is addressed via a Monte Carlo simulation framework that assumes the energy and CO2 emissions coefficients each follow a lognormal distribution. Data sets of total energy and CO2 emissions generated by the Monte Carlo simulation framework with the SEEAM may be used to statistically compare the energy and CO2 emissions of different geotechnical design alternatives. Such comparisons can help facilitate designing for minimum environmental consequences, thus advancing sustainable development within geotechnical engineering. For clarity, the development and application of the SEEAM is illustrated using two different geotechnical case history projects, including rehabilitation of levee LPV 111 in New Orleans, LA, and the construction of foundations for a replacement dormitory on the Virginia Tech campus. / Ph. D.
44

Livscykelanalys av påläggssvetsning på räls / Lifecycle analysis of laser cladding on rail

Eldensjö, Eric, Westling, Karl, Egeman, Otto January 2020 (has links)
Detta arbete undersöker huruvida reparation genom påläggsvetsning kan användas på tågrälsar i Stockholms tunnelbana istället för tillverkning av nya. Olika metallpulver och slitageprofiler analyseras genom en livscykelanalys ur vilken energiförbrukning och CO2-utsläpp jämförs med konventionell tillverkning av tågrälsar. Utifrån olika rekommendationer gällande maximalt sido- och höjdslitage av en rälprofil, skapades en CAD-modell i Solid Edge ur vilken volymen av beläggningen togs fram. Beräkningen av livscykel gjordes sedan med hjälp av programmet CES EduPack och dess inbyggda verktyg Eco Audit tool. Resultatet som togs fram var att laserpåsvetsning minskar både CO2-utsläppen och energiåtgången markant under både transport, tillverkning och materialframtagning för alla material och slitagefall som testades. Som mest sänktes CO2-utsläppen med 95 % och som minst med 85 %. Energiåtgången minskade som mest med 95 % och som minst med 67 %. Materialet som ansågs vara mest lämplig för påläggssvetsning var Rockit 401, då denna bidrog till största minskningen av energiåtgång och koldioxidutsläpp samt hade bäst egenskaper gällande sprickbildning samt hårdhet. / This report investigates the method of laser cladding and its possibility to repair worn down subway tracks as an alternative to manufacturing new ones. Different types of metal powders and wear profiles were studied through a life cycle analysis from which the energy consumption and carbon dioxide emissions were compared to the conventional method of manufacturing rails. Based on data and recommendations for maximum wear a CAD-model in Solid Edge was constructed, from which the volume of the coating was calculated. The life cycle analysis were calculated using the program CES EduPack and its built-in application Eco Audit tool. The result is that laser cladding will lower both the carbon dioxide emission and the energy consumption significantly during both transport, manufacturing and production for every material and wear profiles that were tested. The biggest reduction for carbon dioxide emissions was 95 % and the lowest was 85 %. The biggest reduction of energy consumption was 95 % and the lowest was 67 %. The material that was considered the most suitable for our purpose was Rockit 401 since it contributed to the biggest reduction of both energy consumption and carbon dioxide emission. Rockit 401 also showed good properties regarding cracking and hardness.
45

Comparison of two different materials on frame systems with focus on life cycle analysis. / Jämförelse mellan två olika material på stomsystem med fokus på livscykelanalys.

Ibrahim, Josif, Kateesh, Ahmad January 2020 (has links)
The structural engineer should not only be able to perform design calculations but also findmore efficient solutions for building parts. The purpose of this thesis is to redesign a concreteframe for a house (an apartment building) into a light frame with steel columns andcompartment walls, as well as perform a life cycle analysis for materials on both frames anddetermine the frame with the lowest environmental impact.The result shows that the lightweight frame with steel columns and compartment walls is amuch better choice for the environment as it stands only for 60 000 kg CO2e compared toconcrete frame which stands for 163 000 kg / CO2e. The steel frame emits about 60% lessemissions than the concrete frame.By optimizing steel columns in the upper floors and choosing smaller columns led to ten tonsless mass of steel and less emissions by 15 000 kg / CO2e.The selected compartment wall has a thickness of 309 mm which is 6 mm thicker than theexisting wall which results in a reduction of the area of house by 6 square meters throughoutthe house which can be expensive depending on the location of the house.In conclusion, the material concrete is good when it is needed due to requirements on fire,noise, and durability but also less suitable when not needed. In this case, it is useless with thematerial concrete as the outer wall and can therefore be replaced by a steel columns andcompartment wall instead. / Konstruktören ska inte endast kunna utföra beräkningar utan även hitta effektivare lösningar till byggnadsdelar. Syftet med detta examensarbete är att dimensionera om en betongstomme för ett flerbostadshus till en lättstomme med stålpelare och utfackningsväggar samt även utföra en livscykelanalys för material på stommar och bestämma stommen med lägst miljöpåverkan.Resultatet visar att lättstomme med stålpelare och utfackningsvägg är ett mycket bättre val för miljön då står den för 60 000 kg/CO2e jämfört med betongstomme som står för 163 000 kg/CO2e. Stålstommen släpper ut ungefär 60 % mindre utsläpp än betongstommen.Optimering av stålpelare i övre plan och att välja mindre pelare ledde till tio ton mindre massa stål och även mindre utsläpp på 15 000 kg/CO2e.Den valda utfackningsväggen har tjocklek 309 mm vilket är 6 mm tjockare än den befintliga väggen som i sin tur resulterar i en areaförlust med 6 kvadratmeter i hela huset vilket kan vara dyrt beroende på husets läge.Som slutsats är att materialet betong är bra när det behövs på grund av till exempel brand, ljud och beständighet men även mindre lämpligt när det inte behövs. I detta fall är det mindre lämpligt med materialet betong som yttervägg och man kan därför använda utfackningsvägg med stålpelare istället.
46

A Petroleum Energy, Greenhouse Gas, and Economic Life Cycle Analysis of Several Automotive Fuel Options

Doude, Matthew Carter 17 May 2014 (has links)
A vehicle fuel’s life does not begin when that fuel is pumped into the tank or the battery is charged. Each kilowatt-hour of fuel that is used has a history traceable back to its original feedstock, be it crude oil, corn, solar energy, or others. In this thesis, a life cycle analysis is performed on E10, E85, B20, hydrogen, and electricity, with the well-to-pump fossil fuel energy use and greenhouse gas emissions compared. Results are presented in the form of either energy or mass per kilowatt of fuel at the plug or at the pump. An analysis of the economic viability of each fuel to the consumer is also demonstrated. E85 is found to have the best well-to-pump fossil fuel energy use at 722 Wh/kWh, while hydrogen demonstrates the best well-to-wheel greenhouse gas emissions with 123 g/km (CO2 equivalent) and electricity produces the lowest vehicle lifetime operating cost of $0.241/mile.
47

Techno-Economic and Life Cycle Analysis of Phosphorus Circularity schemes in Agriculture

Sen, Amrita 04 October 2021 (has links)
No description available.
48

Klimatpåverkan – en jämförelse mellan stagade och ostagade pelare

Jonsson, Fredrik January 2022 (has links)
Klimatförändringar till följd av ökade utsläpp av växthusgaser är en av dom största utmaningarna som dagens samhälle står inför. Byggsektorn står för en betydande del av alla utsläpp och dessa behöver minska för att skapa ett hållbart samhälle. Syftet med studien är att undersöka om stagning av pelare leder till minskad klimatpåverkan och om effekten skiljer sig mellan olika konstruktionsmaterial. Studien använder en hallbyggnad med VKR-pelare som referensobjekt. Byggnaden dimensioneras även med limträpelare och HEA-pelare med likvärdig utnyttjandegrad för jämförelse av konstruktionsmaterialen. Pelarna dimensioneras för två fall där dom antingen är stagade eller ostagade. Klimatpåverkan beräknas under hela byggnadens livscykel med indikatorn GWP. Resultatet visar att effekten av stagning skiljer sig åt mellan dom olika konstruktionsmaterialen. Stagning av limträpelare leder inte till någon minskad klimatpåverkan, medan stagning av stålpelare minskar påverkan för båda profilerna. VKR-pelarens klimatpåverkan minskar med 4,6 procent och HEA-pelarens med 14,2 procent. Även om stålpelarna stagas är det limträpelaren som har klart lägst klimatpåverkan, och är därmed det konstruktionsmaterial som är att föredra ur ett hållbarhetsperspektiv. HEA-pelaren som är den av stålpelarna med lägst klimatpåverkan har mer än sju gånger så hög klimatpåverkan som pelaren i limträ. VKR-pelaren har i sin tur mer än dubbelt så hög klimatpåverkan som HEA-pelaren vilket belyser att även valet av stålprofil har betydelse. / Climate changes as a result of increased greenhouse gas emissions is one of the biggest challenges facing todays’s society. The construction sector accounts for a significant part of all emissions and these need to be reduced in order to create a sustainable society. The purpose of the study is to investigate whether bracing of columns leads to reduced climate impact and whether the effect differs between different construction materials. The study uses a hall building with VKR-columns as a reference object. The building is also dimensioned with glulam columns and HEA-columns with an equivalent degree of utilization for comparison of the construction materials. The columns are dimensioned for two cases where they are either braced or not. Climate impact is calculated with the indicator GWP during the building's entire life cycle. The results show that the effect of bracing differs between the different construction materials. Bracing of glulam columns does not lead to any reduced climate impact, while bracing of steel columns reduces the impact on both profiles. The climate impact of the VKR-column decreases by 4.6 percent and the HEA-column decreases by 14.2 percent. Even if the steel columns are braced, it is the glulam column that has by far the lowest climate impact and thus it is the construction material that is preferable from a sustainability perspective. The HEA column, which is the steel column with the lowest climate impact, has a climate impact which is more than seven times as high as the glulam column. The VKR columns climate impact is twice as high as the HEA column, which highlights that the choice of steel profile is also important. / <p>2022-06-22</p>
49

Bioplastics Material Flow Analysis And Their Environmental Impacts / Bioplasters materialflödesanalys och deras miljöpåverkan

Qin, Xinyi January 2022 (has links)
This research is conducted to have a better understanding on the future develop- ment of bioplastics and their environmental impacts. This research first studies the future consumption and waste of bioplastics till 2050 by material flow analysis (MFA).  Life cycle assessment is used to assess the environment impacts of three plastics (bio-PET, PEF and petrol-PET).  The total consumption of bioplastics will be near 5 million tons in 2050 and the waste will be near 4 million tons.  The environment of PEF is the highest among the compared plastic types; Coal as the energy input has the would affect the environment more than other two energy inputs;  Sugarcane has the lowest environment impacts among three raw materials. / Denna forskning genomförs för att få en bättre förståelse för den framtida utvecklingen av bioplaster och deras miljöpåverkan. Först studeras den framtida förbrukningen och avfallet av bioplaster fram till 2050 med hjälp av materialflödesanalyser (MFA). Förbrukningen av bioplaster analyseras för olika tillämpningar. ODYM-modellen används för att beräkna MFA. Två parametrar används som indata i modellen. Den ena är den framtida bioplastförbrukningen som beräknas genom att världsbefolkningen multipliceras med den genomsnittliga produktionskapaciteten per capita, och den andra är livslängden per tillämpning. Tolv bioplasttyper har valts ut för denna analys. Dessa plaster är bio-PET, bio-PE, bio-PA, PTT, PEF, bio-PUR, bio-PP, PLA, PHA, PBAT, PBS och PCL. Den framtida konsumtionen av bioplaster och avfallsmängderna kommer att fortsätta att öka. Den totala förbrukningen av bioplaster kommer att vara nära 5 miljoner ton år 2050 och avfallet kommer att vara nära 4 miljoner ton. Den totala förbrukningen av biopur kommer att vara den högsta av alla elva bioplaster. Den tillämpning där förbrukningen av bio-PA är störst är konsumtionsvaror och beläggningar. Bio-PET kommer också att användas i stor utsträckning som förpackningsmaterial. Livscykelanalys används för att bedöma miljöpåverkan från tre plaster (bio-PET, PEF och petrol-PET). Bedömningen genomförs med hjälp av elva scenarier som är indelade i tre grupper: olika energitillgångar, inklusive kol, hy- dropower och naturgas, och global blandad energi; olika produkter, inklusive bio-PET, PEF och petrol-PET; olika råvaror: sockerrör från Brasilien, majs från USA och potatis från Schweiz. Denna bedömning kvantifieras i sex konsekvenskategorier: global uppvärmning, markanvändning, vattenförbrukning, människors hälsa, ekosystem och markanvändning. PEF:s miljöpåverkan är störst bland de jämförda plasttyperna, kol som energibärare påverkar miljön mer än de andra två energibärarna och sockerrör har den lägsta miljöpåverkan bland de tre råvarorna.
50

COMBINED LAND USE OF SOLAR INFRASTRUCTURE AND AGRICULTURE FOR SOCIOECONOMIC AND ENVIRONMENTAL CO-BENEFITS IN THE TROPICS

Choi, Chong Seok Seok January 2019 (has links)
Solar photovoltaic (PV) generation has been gaining popularity as low carbon energy technology in the face of the global climate change. However, conventional utility-scale PV requires large swaths of land to be occupied for decades which prevents the land from producing food or performing vital ecosystem services. Co-location of PV with crop cultivation is an emerging strategy for mitigating the land use of PV. In order to optimize this strategy, the impact of the plant growth-related soil properties need to be quantified. To this end, the first portion of the thesis investigated the impacts on the soil properties in a re-vegetated solar PV facility in Boulder, Colorado, which was the oldest vegetation-PV co-location site in the world. The second portion of the thesis uses a life cycle analysis (LCA) approach to test the feasibility of co-location of model crop cultivation and solar PV electricity generation in rural Indonesia, and it is the first study to use the LCA study of the co-located solar in the tropics. The first approach revealed that the soil hydrology, grain size distribution, and total carbon and nitrogen are significantly altered from their original state by the construction and presence of photovoltaic arrays, and that those properties had not been restored to their pre-construction levels despite the fact that ten years had passed since re-vegetation of the PV array. The persistence of the altered soil properties meant that the designs regarding re-vegetation or co-location of PV with crops would have to be considered at the beginning of the construction of the PV to minimize the impact on the soil and the existing vegetation. Furthermore, soil moisture was the highest in the soil underneath the western edge of the PV panels, where the western tilt of the PV panel had concentrated the rainfall. The heterogeneity in soil hydrology created by the panels could be manipulated to benefit the growth of vegetation within the PV array. The LCA approach revealed that a hectare of PV arrays with full module density would carbon offsets against diesel electricity generation and the grid, and that the annual supply of electricity from the PV could satisfy the demand of a typical rural Indonesian village several times over. However, the high capital expenditure of solar mean that co-location with full PV module density would not be economically feasible, even with the income stream from the co-located crop cultivation. In order to reduce the capital expenditure, the PV module density for co-location was reduced to half. The combination of reduced capital expenditure and the income stream from the crop made the co-located land use significantly less costly. Additionally, the rural electrification would be able to provide secondary socioeconomic benefits such as avoidance of health costs through operation of public health infrastructures, increased standard of living, and secondary income opportunities from processing of raw materials. However, better subsidies for renewables, specialized loan structures for small-scale renewable systems, and a culture of co-operation between small landholders would need to be implemented before the co-located system becomes affordable to the inhabitants in rural Indonesian villages. / Geology

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