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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.
351

Prefabricerade kontra platsgjutna betongstomväggar: : En utredning ur miljö- och ekonomiskt perspektiv / Prefabricated versus cast-in-situ concrete structures walls : An investigation from an environmental and economic perspective

Fatah Laso, Salar, Omer, Haure January 2023 (has links)
År efter år byggs det allt fler byggnader och med tanke på efterfrågan och behoven kommer det att fortsätta göra det framöver. Kommande åtta åren kommer Sverige att behöva bygga ca 600 000 nya bostäder för att möta hushållstillväxten. Trots medvetenheten om byggbranschens utsläpp och miljöpåverkan samt dess kostnader vid framtagning/tillverkning av nya byggnadsmaterial och fortsatt byggande, fortsätter det byggas på grund av bostadsbristen. Parallellt med byggandet pågår en världsomfattande klimatförändring, vilket lett till varmare temperaturer som orsakat naturkatastrofer etc. Sveriges bygg- och fastighetssektorn stod 2019 för hela 21,1% av Sveriges totala koldioxidutsläpp (CO2) som motsvarar 19,3 miljoner ton koldioxidekvivalenter, vilket motsvarar en femtedel av Sveriges totala utsläpp. Ett av de vanligaste byggnadsmaterialen att bygga stommen för ett flerbostadshus med är betong, där den domineras av två stommetoder, prefabricerad- och platsgjutenbetongstomme. 2020 tillverkades 80 procent av Sveriges flerbostadshus med en stomme av betong.Syftet med denna fallstudie är att jämföra skillnaden mellan betongstommetoderna platsgjuten betongstomvägg mot Prefab stomvägg med avseende på koldioxidutsläppen och ur kostnadsaspekten under byggskede A1-A5, detta för att underlätta valet för entreprenören att välja en lönsam stommetod som släpper ut mindre koldioxidekvivalenter.Denna studie har använt olika undersökningsstrategier för att stärka underlaget för empirin, det vill säga litteraturstudier och fallstudier, dokumentanalys, Livscykelanalys och kalkylering. För att besvara frågeställningarna och uppnå målet med fallstudien har sex olika projekt erhållna från Peab Bostad Syd undersökts med avseende på tillverkningsmetoderna massiva Prefab-, Semi-Prefab- och platsgjutna metoden. Livscykelanalys har undersökts med Byggsektorns Miljöberäkningsverktyg och där kostnadskalkylerna undersöktes med Excel med hjälp av MAP kalkyleringsunderlaget.Resultatet indikerar att den platsgjutna stomväggen ger upphov till utsläpp som är 53,5% respektive 75,3% mindre CO2e/m2 Bruttoarea än skalväggarna respektive massiva Prefabväggen. Resultatet indikerar också att den platsgjutna metoden släpper ut 60,4% CO2e/m3 betong mindre än skalväggarna och 84% CO2e/m3 betong mindre än den massiva Prefabmetoden. Den platsgjutna väggen blir 5,6% billigare än skalväggarna och 21,4% billigare än den massiva prefabricerade väggen per m2 bruttoarea. Den platsgjutna väggen blir 10,4% billigare än skalväggarna och 33,6% billigare per m3 betong för den massiva prefabricerade väggen.Slutsatserna ur studien är att den platsgjutna metoden medför mindre CO2 utsläpp och är ett billigare alternativ jämfört med de prefabricerade metoderna. Denna fallstudie iakttar produkt skedet (A1-A3) och byggproduktionsskedet (A4 och A5) för stomväggar av betong enbart. Denna fallstudie har undersökts med avseende på sex byggnader som har en geografiskplacering i södra Sverige, vilket inte tar hänsyn till norra Sverige som har en kallare temperatur. / Sweden's construction and property sector accounted for 21,1% of Sweden's total carbon dioxide emissions (CO2) in 2019, which corresponds to 19,3 million tons of CO2e. One of the most common building materials to build the structure of an apartment building with is concrete, which is dominated by two structural methods, prefabricated and cast-in-place concrete structures. In 2020, 80% of Sweden's apartment buildings were manufactured with concrete structures. The purpose of this study is to compare the difference between the concrete structure methods, cast-in-place concrete structure walls versus Prefab structure walls about CO2 emissions and from the economic aspect during the construction phase, the production phase, and the construction production phase A1-A5, to facilitate the choice for the contractor to choose a profitable structure method that emits less CO2e.The result indicates that the cast-in-place structure wall emits 53,5% and 75,3% less CO2e/m2 gross area than the semi-prefab and solid Prefab wall. The result indicates that the cast-in-place method emits 60,4% CO2e/m3 less concrete than semi-precast and 84% CO2e/m3 less concrete than the massive Prefab method. The cast-in-place wall will be 5,6% cheaper than the semi-prefabricated- and 21,4% cheaper than the massive prefabricated wall m2 gross area. The cast-in-place wall will be 10,4% cheaper than the semi-prefabricated- and 33,6% cheaper SEK/m3 concrete for the massive Prefab walls. The conclusions from the study are that the cast-in-place method entails fewer CO2 emissions and is a cheaper alternative compared to the prefabricated methods. This study observes the LCA stages A1-A5 for concrete structure walls only. This study has investigated about six buildings that have a geographical location in southern Sweden, which does not take into account northern Sweden, which has a colder temperature.
352

Dimensioning and Life Cycle Costing of Battery Storage System in residential housing- A case study of Local System Operator Concept

Mehdijev, Shamil January 2017 (has links)
growing concern on achieving environmental sustainability and at the same time making economical savings has become a necessity in our society. The prices of different battery energy storage technologies together with PV cells are declining all around the globe which has led to the fact that there is an increased interest in investing and using these technologies to be able to reach environmental sustainability. The combined system however, must be accurately calculated both when it comes to the sizing and the different costs related to the combined system to be able to make an economical saving. This thesis addresses both of those aspects in Sweden where a residential building with roof-top installed PV system is assessed with a battery energy storage system. An investigation is necessary to be able to assess the different battery storage technologies available in the market today with their specific technical and economical specifications. The electricity market in Sweden, the role of the Distribution System Operator on the electricity pricing with different time tariffs and fuse size subscription, PV generation and battery specifications are investigated and modeled in this study. Sizing of the different battery technologies for the given system is accomplished through a methodology that is developed in this project for the Swedish system. The calculated size of the battery is then used in the Life Cycle Cost analysis, using Monte Carlo simulations for a chosen period of 25 years.Calculations shows that the most appropriate size for the battery system with the given parameters is 6 kWh for all the battery types investigated in this study. The size of the batteries is also shown to be mainly dependent on the charging/discharging time together with the set fuse size margin. Profitability of the Battery Energy Storage system is proven to be mainly dependent on the fuse size downgrade. Sulphur-Sodium battery result in the greatest savings while Vanadium Redox batteries in the least when sizing the batteries. Lithium-Ion battery technology however is most likely to result in the lowest Levelized Cost of Electricity, total- and cycle costs while the highest Net Present Value with 90 % probability in the Monte Carlo simulations. Lithium-Ion battery technology is also found to have the highest probability of having a positive NPV compared to the lowest probability for Sulphur-Sodium battery technology. Lead-Acid battery technology is however shown to have the least uncertainties compared to other Battery Energy Storage technologies due to its maturity. It is additionally shown that government subsidy plays a crucial role when investing in the battery storage system. However, even with the case of removed government subsidy, Lithium-Ion battery technology still results in the largest probability of having a positive NPV while Sulphur-Sodium battery technology results in the lowest probability of having a positive NPV. / Den växande oron för att uppnå miljömässig hållbarhet och samtidigt göra ekonomiska besparingar har blivit en nödvändighet i vårt samhälle. Priserna på olika energilagrings teknologier så som batterier tillsammans med PV-celler minskar runt om i världen vilket har lett till att det finns ett ökat intresse när det gäller att investera och använda dessa teknologier för att kunna nå miljömässig hållbarhet. Det kombinerade systemet måste dock noggrant beräknas både när det gäller storleken och de olika kostnaderna för det kombinerade systemet för att kunna göra en ekonomisk besparing. Denna avhandling behandlar båda dessa aspekter i Sverige där en bostadsbyggnad med takmonterat PV system utvärderas med ett batteri system. En undersökning är nödvändig för att kunna bedöma de olika batteri teknologier som finns tillgängliga på marknaden idag med sina specifika tekniska och ekonomiska specifikationer. Elmarknaden i Sverige, Distribution System Operatörs roll för elprissättning med olika tidstariffer och säkringsabonnemang, PV-generation och batterispecifikationer undersöks och modelleras i denna studie. Dimensionering av olika batteri teknologier för det givna systemet uppnås genom en metod som utvecklats i detta projekt för det svenska systemet. Den beräknade storleken på batteriet används sedan i livscykelkostnadsanalysen, med Monte Carlo-simuleringar under en vald period på 25 år. Beräkningar visar att den optimala storleken för batterisystemet med de angivna parametrarna är 6 kWh för alla batterityper som undersöktes i denna studie. Batteriets storlek visar sig också vara huvudsakligen beroende av laddning / urladdningstiden tillsammans med den inställda säkrings storleken. Lönsamheten hos batterilagringssystemet visar sig vara huvudsakligen beroende av säkringens nedgradering. Svavel-Natriumbatteriet resulterar i de största besparingarna medan Vanadium Redox batteriet i de minsta när dimensionering av batteriet äger rum. Litium-Ion batteriet är emellertid sannolikt att leda till den lägsta nivån av elkostnader, total- och cykelkostnader, medan det högsta nettoförsäljningsvärdet med 90% sannolikhet i Monte Carlo-simuleringarna. Litium-Ion batteriet befanns också ha den högsta sannolikheten att ha en positiv NPV jämfört med Svavel-Natriumbatteriet som resulterar i den lägsta sannolikheten. Lead-Acid batteriet visar sig ha den minsta osäkerheten i jämförelse med andra batterilagrings teknologier på grund av dess mognad. Det framgår dessutom att statlig subvention spelar en avgörande roll när man investerar i ett batteri lagrings system. Dock även med borttagna statliga subventioner, resulterar Litium-Ion batteriet fortfarande största sannolikheten för att ha en positiv NPV, medan Svavel-Natriumbatteriet resulterar den lägsta sannolikheten för att ha en positiv NPV.
353

RELIABILITY-BASED DESIGN OPTIMIZATION OF CORROSION MANAGEMENT STRATEGIES FOR REINFORCED CONCRETE STRUCTURES

Sajedi, Siavash January 2017 (has links)
No description available.
354

Financial Analysis and Global Supply Chain Design : A Case Study of Blood Sugar Monitoring Industry

Younes Sinaki, Roohollah January 2017 (has links)
No description available.
355

Life-cycle Cost Analysis of Nutrient Reduction Technologies Employed in Municipal Wastewater Treatment

Brown, Colin Barrett 09 June 2016 (has links)
No description available.
356

Value-added Conversion of Waste Cooking Oil, Post-consumer PET Bottles and Soybean Meal into Biodiesel and Polyurethane Products

Dang, Yu 20 December 2016 (has links)
No description available.
357

Three studies on the economics of food safety

Cho, Bo-Hyun 29 September 2004 (has links)
No description available.
358

Economic evaluation of preventive methods used in dentistry – a systematic review

Westerlund, Louise, Simonsson, Anna January 2016 (has links)
Syfte: Syftet med studien var att undersöka ekonomiska utvärderingar av preventiva metoder som används inom tandvården genom att göra en systematisk litteraturöversikt och besvara frågor om vilka preventiva metoder som analyserats avseende kostnad och effekt samt vilka typer av ekonomiska utvärderingar som analyserats. Material och metod: En sökningsstrategi genomfördes och PubMed, The Cochrane Library och Web of Science utgjorde databaser för litteratursökningen. Inklusions- och exklusionskriterier fastställdes och ett protokoll utgjorde grunden för läsningen av de inkluderade studierna i fulltext. En kritisk granskning av de inkluderade studierna genomfördes genom att använda ett andra protokoll. Resultat: Totalt 38 publikationer om ekonomiska utvärderingar av preventiva metoder som används inom tandvården inkluderades. Studier om kariespreventiva metoder var av övervägande majoritet (n=35) och endast ett fåtal studier utvärderade preventiva metoder för andra sjukdomar (n=3). Den vanligaste preventiva metoden som utvärderades var fissurförsegling (n=8) följt av fluorlackning (n=6) och vattenfluoridering (n=3). Många studier utvärderade kombinerade preventiva metoder (n=12). Typerna av ekonomiska utvärderingar var CEA (n=16) följt av CA/Cost-minimization analysis (n=10), CBA (n=3), en kombination av CEA och CBA (n=5), CUA (n=1) och en kombination av CEA och CA (n=1). Konklusion: Även om studierna om ekonomiska utvärderingar av preventiva metoder som används inom tandvården är betydligt fler än när SBU-rapporterna publicerades så kan ingen generell slutsats beträffande kostnadseffektiviteten dras på grund heterogenitet i design och sätt att analysera. Fler välgjorda studier rekommenderas. / Aims: The aim of this study was to examine economic evaluations of preventive methods used in dentistry by using a systematic review approach and answering questions about which preventive methods used in dentistry that have been analysed regarding costs and effects and what types of economic evaluations that have been conducted. Material and method: A search strategy were conducted and PubMed, The Cochrane Library and Web of Science formed the basis of the literature search. Inclusion- and exclusion criteria were defined and a protocol was made for full-text reading of the included publications. A critical appraisal of the included publications was made using a second protocol. Results: A total of 38 publications on economic evaluations of preventive methods used in dentistry were included. Publications on caries preventive methods were of overwhelming majority (n=35) and only a few publications evaluated preventive methods for other diseases (n=3). The most common evaluated preventive method was pit and fissure sealant (n=8) followed by fluoride varnish (n=6) and water fluoridation (n=3). Most publications evaluated combined preventive methods (n=11). Types of economic evaluations were CEA (n=16) followed by CA/Cost-minimization analysis (n=10), CBA (n=3), a combination of CEA and CBA (n=5), CUA (n=1) and a combination of CEA and CA (n=1). Conclusions: Publications on economic evaluations of preventive methods used in dentistry were considerably more than when the SBU reports were published. Yet, no general conclusions could be drawn regarding cost-effectiveness due to heterogeneity in design and way of analyses. Future well-designed studies are recommended.
359

Sustainability evaluation of proposal for a decentralized office space. : Case study, Växjö, Sweden

Frenliden, Carl, Ljungman, Martin January 2022 (has links)
As the COVID-19 pandemic became widespread around the world, the need to be able to work from home became clear to help reduce the spread of the virus, while at the same time showing that working from home could be successful in the future. While working from home can be positive, it also has drawback as reduce social interactions, hard to set working boundaries and more. This paper examines the viability to introduce a decentralized office space trough environmental sustainability, economic sustainability and social sustainability for a reference apartment building and an energy renovated one compared to a centralized office space. This study shows that working from a decentralized office space will reduce emissions with better utilization of the apartment building, saving the companies money and having a reasonable payback period for investors, while giving employees better personaleconomic and more free time without compromising on the social sustainability from not meeting people and having a hard time to different on working hours and non-working hours.
360

An evaluation of biodiesel policies : The case of palm oil agro-industry in Indonesia

Harahap, Fumi January 2018 (has links)
Oil palm has flourished as an economically vital crop in Indonesia given its use in both food and non-food products (including biodiesel) for domestic and export markets. However, the expansion of oil palm plantations in Indonesia is controversial. While the crop generates fiscal earnings for the country, and regular income streams for farmers and companies, oil palm plantation expansion is claimed to cause deforestation, environmental degradation and biodiversity losses. At the same time, there is a national target to reduce GHG emissions from land use change and the production of palm oil. Climate change mitigation goals also include ambitious targets to blend biodiesel with fossil diesel in various economic sectors. This thesis looks at the palm oil agro-industry, from oil palm plantation to crude palm oil (CPO) production, and CPO based biodiesel production. It proposes a policy evaluation to verify policy implications in relation to the issue of land use allocation, and the poor profitability in palm oil biodiesel production. The overarching objective is to evaluate the effectiveness of prevailing policies used to promote the palm oil agro-industry for biodiesel production in Indonesia. The thesis is framed by policy research and ex-post policy evaluation. The focus is on the process of policy formulation and implementation, rather than outcome evaluation. Two specific analytical frameworks are used to answer the research questions while addressing the criteria of effectiveness in policy evaluation: (i) policy coherence analysis and (ii) life cycle cost analysis. Qualitative indicators are used to measure the coherence of biofuel policy with other sectoral policies (agriculture, climate and forestry) in relation to land allocation. Quantitative economic indicators are used to compare the costs and benefits of conventional palm oil biodiesel production with a biorefinery conceptual plant. There are valuable lessons to be learnt from this policy evaluation. The results indicate areas in which policy effectiveness can be improved. For land allocation, adjustments and improvements in policy formulation and implementation are crucial. Uncertainties when it comes to the allocation of land to meet multi sectoral policy goals are to be addressed by clarifying land use definitions and categories, which should be backed up by consistent land use definitions in various policy documents. The dual land classification presently applied should move towards a single land classification, linking actual landscape coverage and the legal status of the land. Policy information and guidance across sectoral policies should be compiled in a single database. Such a publicly available database would help enhance the efficiency of land allocation for multiple policy purposes. More importantly, the formulation of biodiesel policy has to engage various sectoral policies that compete for the same resources. The biorefinery conceptual plant allows the reduction of government subsidies, while also providing a pathway to enhance the use of renewable energy and reduce GHG emissions. Policies have been designed to enhance plant profits through the improved utilisation of biomass residues in the palm oil mill for energy generation and composting. However, the low implementation rate of policies indicates the need to improve the effectiveness of policy implementation, and therefore the need for better monitoring processes, and possibly more stringent consequences for non-compliance. / <p>QC 20180223</p>

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