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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.
161

Sustainability Assessment Of Wind Energy For Buildings

Noori, Mehdi 01 January 2013 (has links)
Due to increasing concerns for global climate change, onshore and offshore wind energy technologies have stimulated a tremendous interest worldwide, and are considered as a viable solution to mitigate the environmental impacts related to electricity generation. Although wind energy technologies have been considered as one of the cleanest energy sources, they have a wide range of direct and indirect environmental impacts when the whole supply chain is considered. This study aims to quantify the direct and indirect environmental impacts of onshore and offshore wind power technologies by tracing all of the economy-wide supply chain requirements. To accomplish this goal, we developed a comprehensive hybrid life cycle assessment (LCA) model in which process-based LCA model is combined with the economic input-output (EIO) analysis. The analysis results show that on average, concrete and steel and their supply chains are responsible for 37% and 24% of carbon footprint, consequently. On average, offshore wind turbines produce 48% less greenhouse gas emissions per kWh produced electricity than onshore wind turbines. For the onshore wind turbines, concrete, aggregates, and crushed stone approximately consume 95% of total water in this construction phase. On the other hand, concrete, lead, copper, and aggregate are responsible for around 90% of total water for the offshore wind turbines. It is also found that the more capacity the wind turbine has, the less environmental impact the wind turbine generates per kWh electricity. Moreover, based on the economic and environmental impacts of studied wind turbines and also three more nonrenewable energy sources, this study develops a decision making framework to understand the best energy source mix for a building in the state of Florida. This framework accounts for the uncertainty in the input material by deploying a Monte Carlo iii simulation approach. The results of decision making framework show that natural gas is a better option among nonrenewable sources. On the other hand, V90-3.0 MW offshore wind turbine is the best source of energy among renewable energy sources for a building. The findings of this research are critical for policy makers to understand the direct and indirect environmental impacts of different onshore and offshore wind energy systems. Also this study furnishes the decision maker with a range of possible energy mixes based on different economic and environmental weights.
162

Surface Modifications of Reverse Osmosis Membranes for Removal of Bromide and Reduction of Fouling

Seo, Joseph 01 June 2020 (has links) (PDF)
Reverse osmosis (RO) is widely used for water reuse and desalination. Although RO membranes are known for their high salt rejection and practical permeate flux, their performance can be impaired by fouling, and their removal of some disinfection byproducts and their precursors (e.g., bromide, N-Nitrosodimethylamine [NDMA]) does not meet drinking water standards. RO membrane modifications have been widely studied to overcome these limitations. In this research, RO membranes were grafted with cationic polymers to induce a positive charge on the RO membrane surface. This modification aimed at enhancing the rejection of negatively charged bromide ions by removing them from solution by binding them to the membrane surface. The results showed that the modified (positively charged) RO membranes achieved lower rejection (82% rejection) for bromide ions compared to the unmodified ones (94.5% rejection). This behavior was likely a result of increased concentration polarization of the bromide ions at the membrane surface and/or increase in porosity of the modified membranes. Calculations based on the film theory indicate that the concentration of bromide ions at the surface of the modified membrane was 1371 ppm compared to 1307 ppm at the surface of the unmodified membrane. Evidently, the polymer attraction energy was not sufficient to keep the bromide ions attached to the membrane surface and prevent their diffusion across the membrane. Although the goal of the modification in the current study (i.e., enhancing removal of bromide ions) was not met, the permeate flux of the modified membrane was improved compared to the unmodified one. The literature suggests that increasing flux after modification is likely a result of increase in membrane pore size and hydrophilicity. In addition to the experimental work conducted in this study, a multi-criteria decision analysis was performed to prioritize research on surface modifications of reverse osmosis membranes. It was found that surface modifications have been mainly focused on reducing membrane fouling and to a much lower extent on removal of disinfection byproducts and their precursors. The RO membrane modification alternatives for fouling reduction and N-Nitrosodimethylamine (NDMA) removal were ranked based on multiple criteria using the Analytical Hierarchy Process (AHP) and the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). This multi-criteria decision analysis process resulted in the identification of the top five promising modifications to reduce fouling and improve NDMA rejection. Grafting and coating the RO membranes with complex polymeric salts were the highest ranked modification approaches to reduce fouling. Heat-treatment of RO membranes achieved the highest NDMA rejection (98%); however, this technique was the second highest ranked modification approach for NDMA removal because it scored lower for other evaluation criteria.
163

Spatial vulnerability analysis and thematic mapping of urban floods: A case study of 100-year floodplain areas of Birmingham, Alabama

Hossain, Mohammad Khalid 25 November 2020 (has links)
The social and economic impact of urban flooding is becoming more severe in the United States over time. Urban areas are mostly vulnerable to flash floods because of the impervious surface, which increases the surface runoff. More than 80 percent of people live in urban areas in the United States, and they are at higher risk of urban flooding. Although many urban areas have a higher risk of urban flooding, there is still a significant knowledge gap of understanding between the minority's and nonminority's vulnerability to urban floods. Therefore, using Birmingham, Alabama, as a study area, this research designs a quantitative thematic mapping method to assess the flood risks of urban population and buildings. In this research, census data was used to assess urban residents' vulnerability to flooding using thematic mapping method – location quotient (LQ) and compare it with the widely used social vulnerability index. The findings suggest that the aggregation of White populations is much higher compared to minorities. This research also developed a flood risk model using integrated GIS and cartographic approach considering different environmental factors that influence the urban floods. This study found that the Valley Creek area is the highest flood risk zone in Birmingham, and has the highest percentage of residential (i.e., 56.14 %) and commercial (i.e., 75.34 %) buildings located in very high flood risk areas. The decennial census data from 1990 to 2015 was used to examine whether vulnerable population groups aggregated more in the flooding areas or moved away from Birmingham's flooding areas in the past thirty years. The findings of this research indicate that most minorities are aggregating more in the floodplain areas, whereas the non-minorities are moving away from the flooding regions.
164

Exploring the Nature of Benefits and Costs of Open Innovation for Universities by Using a Stochastic Multi-Criteria Clustering Approach: The Case of University-Industry Research Collaboration

Zare, Javid January 2022 (has links)
Open innovation that Henry Chesbrough introduced in 2003 promotes the usage of the input of outsiders to strengthen internal innovation processes and the search for outside commercialization opportunities for what is developed internally. Open innovation has enabled both academics and practitioners to design innovation strategies based on the reality of our connected world. Although the literature has identified and explored a variety of benefits and costs, to the best of our knowledge, no study has reviewed the benefits and costs of open innovation in terms of their importance for strategic performance. To conduct such a study, we need to take into account two main issues. First, the number of benefits and costs of open innovation are multifold; so, to have a comprehensive comparison, a large number of benefits and costs must be compared. Second, to have a fair comparison, benefits and costs must be compared in terms of different performance criteria, including financial and non-financial. Concerning the issues above, we will face a complex process of exploring benefits and costs. In this regard, we use multiple criterion decision-making (MCDM) methods that have shown promising solutions to complex exploratory problems. In particular, we present how using a stochastic multi-criteria clustering algorithm that is one of the recently introduced MCDM methods can bring promising results when it comes to exploring the strategic importance of benefits and costs of open innovation. Since there is no comprehensive understanding of the nature of the benefits and costs of open innovation, the proposed model aims to cluster them into hierarchical groups to help researchers identify the most crucial benefits and costs concerning different dimensions of performance. In addition, the model is able to deal with uncertainties related to technical parameters such as criteria weights and preference thresholds. We apply the model in the context of open innovation for universities concerning their research collaboration with industries. An online survey was conducted to collect experts' opinions on the open-innovation benefits and costs of university-industry research collaboration, given different performance dimensions. The results obtained through the cluster analysis specify that university researchers collaborate with industry mainly because of knowledge-related and research-related reasons rather than economic reasons. This research also indicates that the most important benefits of university-industry research collaboration for universities are implementing the learnings, increased know-how, accessing specialized infrastructures, accessing a greater idea and knowledge base, sensing and seizing new technological trends, and keeping the employees engaged. In addition, the results show that the most important costs are the lack of necessary resources to monitor activities between university and industry, an increased resistance to change among employees, conflict of interest (different missions), an increased employees' tendency to avoid using the knowledge that they do not create themselves, paying time costs associated with bureaucracy rules, and loss of focus. The research's findings enable researchers to analyze open innovation's related issues for universities more effectively and define their research projects on these issues in line with the priorities of universities.
165

Further Applications of Reactive In-Mold Coating (IMC): Effect of Inhibitor and Carbon Nano-Particles

BHUYAN, MOHAMMAD SHAHAJAHAN KABIR 25 October 2018 (has links)
No description available.
166

Limiting microplastic pollution from municipal wastewater treatment : A circular economic approach / Begränsning av mikroplastföroreningar från kommunal avloppsrening : En cirkulär ekonomisk strategi

van Osch, Jordy January 2020 (has links)
The increasing amount of microplastics found in the environment have underscored the urgency to identify, develop and deploy scenarios in which municipal wastewater treatment plants (MWWTPs) limit the release of urban microplastics into the environment. Simultaneously, the global trend towards a circular economy has defined the conditions for these scenarios in relation to the water-energy- nutrient nexus. This study has created a novel framework between studies into treatment technologies for microplastics removal in wastewater streams and circular economic objectives from policymakers with regard to the water-energy-nutrient nexus. The results of this study build on the existing evidence that MWWTPs release significant amounts of microplastics to both terrestrial and aquatic environments. This study has demonstrated how Multi-criteria Analysis (MCA) can be applied to analyse wastewater treatment scenarios for their ability to limit microplastic pollution from MWWTPs, whilst taking the water-energy- nutrient nexus into account. The MCA has identified MBR inci-eco as the best performing circular economic scenario for limiting microplastic pollution from MWWTPs in to be constructed plants. This scenario includes a Membrane Bioreactor (MBR) with Anaerobic Digestion, energy recovery through incineration and Phosphorus recovery through Ecophos. If already existing MWWTPs aim to upgrade their facility to limit microplastic pollution, CASPACUF with Pyreg as an energy-nutrient recovery is seen as the best performing scenario. The powder activated carbon with ultra filtration (PAC-UF) system would then be installed as an additional polishing step to an existing conventional activated sludge (CAS) system, significantly reducing upfront investment costs. Academia can build upon these results to initiate additional research into novel microplastic filtration specific technologies, business model innovation for wastewater treatment and microplastic pollution prevention at the source and in stormwaters. National and international policymakers should ban the distribution and sale of biosolids for direct land application to limit the pollution of microplastics from bio-solids. Furthermore, efforts should be put in place to limit microplastic pollution at the source by stimulating policies for a ban on the use of microbeads, limit tyre wear and improving design for e.q. washing machines. / Den ökande mängden mikroplast som finns i miljön har understrukit brådskan i att identifiera, utveckla och tillämpa strategier där kommunala avloppsreningsverk (MWWTP) begränsar utsläpp av urbana mikroplaster. Samtidigt har den globala trenden mot en cirkulär ekonomi definierat villkoren för dessa scenarier i förhållande till vatten-energi-näring-näxan. Denna studie har tagit fram ett nytt ramverk mellan studier om reningsteknologier för avlägsnande av mikroplast i avloppsvattenströmmar och cirkulära ekonomiska mål från beslutsfattare med avseende på water-energy-nutrient nexus. Resultaten av denna studie bygger på befintliga bevis på att kommunala avloppsreningsverk släpper ut betydande mängder mikroplast i både mark- och vattenmiljöer. Denna studie har visat hur Multi-Criteria Analysis (MCA) kan användas för att analysera avloppsreningsscenarier utifrån deras förmåga att begränsa mikroplastföroreningar från reningsverk, samtidigt som man tar hänsyn till vatten-energi-näring-näxan. MCA har identifierat MBR-inci-eco som det bäst presterande cirkulära ekonomiska scenariot för att begränsa mikroplastföroreningar från nya verk. Detta scenario inkluderar en Membrane Bioreactor (MBR) med anaerobisk nebrytning, energiåtervinning genom förbränning och fosforåtervinning genom Ecophos. Om redan befintliga verk ska uppgradera sin anläggning för att begränsa mikroplastföroreningar, ses CASPACUF med Pyreg som energi-näringsåtervinning som det bästa scenariot. Det pulveraktiverade kolet med ultrafiltreringssystemet (PAC-UF) skulle sedan installeras som ett ytterligare poleringssteg till ett befintligt konventionellt system för aktiverat slam (CAS), vilket avsevärt minskar investeringskostnaderna. Framtida forskning kan använda dessa resultat för att undersöka nya mikroplastfiltreringsspecifika tekniker, affärsmodellinnovation för avloppsrening och förebyggande av mikroplastförorening vid källan och i stormvatten. Nationella och internationella beslutsfattare bör förbjuda distribution och försäljning av biosolids för direkt markanvändning för att begränsa mikroplastföroreningar från biosolids. Vidare bör åtgärder vidtas för att begränsa mikroplastföroreningar vid källan genom att stimulera policyer för ett förbud mot användning av mikrokulor, begränsa däckslitage och förbättra designen för e.q. tvättmaskiner.
167

Prioritising biochar application to arable land in Sweden : A spatial multi-criteria analysis / Prioritering av biokolsapplikationer på åkermark i Sverige : En rumslig multikriterieanalys

Osslund, Fabian January 2020 (has links)
Biochar, the solid product of thermal conversion of biomass with little or no available air, is acknowledged as a carbon dioxide removal technique and soil enhancer among other applications. Its potential soil enhancing properties consists of increased water and nutrient holding capacities, liming effects and sorption of pollutants. However, not all soils benefit equally from biochar amendments. The thesis aims to investigate the suitability of biochar applications to agricultural soils in Sweden and communicate the results visually with a biochar indication map, illustrating where biochar could serve the highest benefits as a soil improver. A literature review was carried out to analyse the soil enhancing opportunities of biochar applications, which determined that the criteria soil texture, nitrogen leaching, ground moisture, soil pH and soil organic matter (SOM) were suitable for the analysis in a Swedish context. Then, a multi-criteria analysis was conducted in ArcGIS, based on spatial data of these criteria. Each arable land block was assigned a biochar class, varying from high indication to no indication. Arable land was considered highly recommended for biochar applications if the soil texture was sandy and at least one of the soil criteria was beyond a limiting agronomic threshold. At the national level, high indication for biochar application occupied 24.2% (528 thousand ha) of the arable land in Sweden, while the remaining land had either medium indication (13%), low indication (3.5%) or no indication (59.3%). Despite spatial variations, all Swedish counties (with data coverage above 84%) had at least 2% of high indication arable land. In particular, 66.1% of Halland’s arable land showed high indication. In turn, Skåne had the largest area (148 thousand ha, 35.7%) with high indication for biochar applications. The corresponding biochar volume potential, at the national level, suggested that between 0.5 and 26.4 million tonnes biochar can be applied to arable land with high indication for biochar applications, given application rates between 1 and 50 tonnes/ha over a 20 year timeframe. This means that arable land in Sweden can accommodate for a future production of 500 000 tonnes per year, which was suggested as an upper limit in an inquiry from the Swedish government, if application rates remain below 20 tonnes/ha. The multi-criteria analysis performed includes several subjective choices and uncertain parameters (criteria combination, data accuracy, agronomic thresholds, and classification scheme). Therefore, the biochar indication maps cannot yet be used for farm- or field-level recommendations for biochar applications. Nonetheless, despite uncertainties, the national- and county- level indication maps may still provide interesting order of magnitude. More field experiments are needed in Sweden as well as a more detailed analysis. To be able to make more precise recommendations, the present analysis can be refined by connecting all criteria to physical agricultural mechanisms and to the properties of biochar, and by using spatial data with higher resolution or even field-level data. This said, models need to be validated with experimental data, which is to date, non- existent: controlled biochar field experiments are therefore needed in Sweden. / Biokol, en solid produkt från termisk omvandling av biomassa med begränsat syre tillgängligt, är identifierad som en möjlig teknik för att minska halten av koldioxid i atmosfären och som jordförbättrare bland andra applikationer. Dess potentiella jordförbättrande egenskaper består av vattenhållning, näringsbindning, balansering av pH-värdet och minskad biotillgänglighet av föroreningar. Däremot så drar inte alla jordar samma nytta av biokolapplikationer. Arbetet syftar till att undersöka lämpligheten av biokolapplikationer på jordbruksmark i Sverige och kommunicera resultaten visuellt med en indikationskarta. En litteraturstudie genomfördes för att analysera jordförbättringsmöjligheterna till följd av biokolsapplikationer. Det fastställdes att kriterierna jordtyp, kväveläckage, markfuktighet, pH och organiskt material var lämpliga för analys i svensk kontext. En multikriterieanalys utfördes i ArcGIS, baserat på rumsliga data för dessa kriterier. Vardera jordbruksblock tilldelades en biokolklass, som varierade mellan hög indikation och ingen indikation. Jordbruksmark ansågs högt rekommenderad för biokolapplikationer om jordtypen var av sandig karaktär och minst ett av kriterierna översteg ett begränsande tröskelvärde. På nationell nivå ockuperade hög indikation för biokolapplikationer 24.2% (528 tusen hektar) av Sveriges jordbruksmark, medan den återstående marken hade antingen måttlig indikation (13%), låg indikation (3.5%) eller ingen indikation (59.3%). Trots rumsliga variationer, hade samtliga svenska län (med datatillgänglighet över 84%) minst 2% åkermark med hög indikation. I synnerhet, 66.1% av Hallands åkermark visade hög indikation. Vidare, Skåne hade den största arealen (148 tusen hektar, 35.7%) med hög indikation för biokolapplikationer. Den motsvarande potentialen för biokol, på nationell nivå, antyder att mellan 0.5 och 26.4 miljoner ton biokol kan appliceras på jordbruksmark med hög indikation för biokolapplikationer, givet appliceringsgrader mellan 1 och 50 ton/hektar över en 20-årsperiod. Detta innebär att svensk jordbruksmark kan rymma en framtida produktion på 500 000 ton per år, förslaget av en statlig utredning, ifall appliceringsgraden förblir under 20 ton/ha. Den utförda multikriterieanalysen inkluderar flertalet subjektiva val och osäkerheter (kriteriakombination, datans noggranhet, tröskelvärden, och klassificeringsmetod). Därmed kan indikationskartorna för biokol ännu inte användas för rekommendationer på jordbruksblocknivå. Resultaten kan emellertid, trots osäkerheter, antyda intressanta storleksordningar på nationell- och länsnivå. Fler svenska fältexperiment samt en mer detaljerad analys behövs. För att kunna ge mer exakta rekommendationer, kan den nuvarande analysen utvecklas genom att koppla samtliga kriterier till fysiska jordbruksmekanismer och biokolsegenskaper och genom att tillämpa rumsliga data av högre upplösning eller till och med fältnivådata. Modeller måste valideras med experimentella data, som hittills är obefintlig: kontrollerade fältförsök med biokol behövs därmed i Sverige.
168

Assessment and relative sustainability of common types of roadside noise barriers

Oltean-Dumbrava, Crina, Miah, Abdul H.S. 18 June 2016 (has links)
Yes / There is increasing legislative and public pressure for the design and build of road infrastructure schemes to achieve better sustainability performance. Roadside noise barriers (RNBs) form a major part of the growing road infrastructure system in mitigating undesirable road noise to impacted communities. However, the relative sustainability of common RNBs is little understood in the research and industry literature. This makes it difficult for stakeholders to make informed decisions with regards to the sustainable design and procurement of RNBs. This paper presents nowel research carried out to assess and rank the relative sustainability of 13 RNB types using three multi criteria analysis (MCA) techniques, i.e. Simple Additive Weighting (SAW), Preference Ranking Organisation MeTHod for Enrichment Evaluations (PROMETHEE), and Elimination et Choice Translating Reality (ELECTRE III). The paper concludes that the presented sustainability rankings of the main RNB types from least sustainable to most sustainable will support the relevant stakeholders, involved in the planning, design, and procurement stages, to evaluate the sustainability of RNB options as either part of a large highways scheme or standalone project. The presented results will save significant analysis time and costs in cases whereby it is unfeasible to conduct MCAs. The presented sustainability asssessment methodology may also provide the basis for an industry sustainability certification sceheme and in turn support advancing the sustainability transport agenda. / FP7 Quiesst research grant funded by the EU.
169

A Decision Support System for the Electrical Power Districting Problem

Bergey, Paul K. 28 April 2000 (has links)
Due to a variety of political, economic, and technological factors, many national electricity industries around the globe are transforming from non-competitive monopolies with centralized systems to decentralized operations with competitive business units. This process, commonly referred to as deregulation (or liberalization) is driven by the belief that a monopolistic industry fails to achieve economic efficiency for consumers over the long run. Deregulation has occurred in a number of industries such as: aviation, natural gas, transportation, and telecommunications. The most recent movement involving the deregulation of the electricity marketplace is expected to yield consumer benefit as well. To facilitate deregulation of the electricity marketplace, competitive business units must be established to manage various functions and services independently. In addition, these business units must be given physical property rights for certain parts of the transmission and distribution network in order to provide reliable service and make effective business decisions. However, partitioning a physical power grid into economically viable districts involves many considerations. We refer to this complex problem as the electrical power districting problem. This research is intended to identify the necessary and fundamental characteristics to appropriately model and solve an electrical power districting problem. Specifically, the objectives of this research are five-fold. First, to identify the issues relevant to electrical power districting problems. Second, to investigate the similarities and differences of electrical power districting problems with other districting problems published in the research literature. Third, to develop and recommend an appropriate solution methodology for electrical power districting problems. Fourth, to demonstrate the effectiveness of the proposed solution method for a specific case of electric power districting in the Republic of Ghana, with data provided by the World Bank. Finally, to develop a decision support system for the decision makers at the World Bank for solving Ghana's electrical power districting problem. / Ph. D.
170

Application of the Analytic Hierarchy Process Optimization Algorithm in Best Management Practice Selection

Young, Kevin D. 29 September 2006 (has links)
The efficiency of a best management practice (BMP) is defined simply as a measure of how well the practice or series of practices removes targeted pollutants. While this concept is relatively simple, mathematical attempts to quantify BMP efficiency are numerous and complex. Intuitively, the pollutant removal capability of a BMP should be fundamental to the BMP selection process. However, as evidenced by the absence of removal efficiency as an influential criterion in many BMP selection procedures, it is typically not at the forefront of the BMP selection and design process. Additionally, of particular interest to any developer or municipal agency is the financial impact of implementing a BMP. Not only does the implementation cost exist, but there are long-term maintenance costs associated with almost any BMP. Much like pollutant removal efficiency, implementation and maintenance costs seem as though they should be integral considerations in the BMP selection process. However, selection flow charts and matrices employed by many localities neglect these considerations. Among the categories of criteria to consider in selecting a BMP for a particular site or objective are site-specific characteristics; local, state, and federal ordinances; and implementation and long-term maintenance costs. A consideration such as long-term maintenance cost may manifest itself in a very subjective fashion during the selection process. For example, a BMPs cost may be of very limited interest to the reviewing locality, whereas cost may be the dominant selection criterion in the eyes of a developer. By contrast, the pollutant removal efficiency of a BMP may be necessarily prioritized in the selection process because of the required adherence to governing legislation. These are merely two possible criteria influencing selection. As more and more selection criteria are considered, the task of objectively and optimally selecting a BMP becomes increasingly complex. One mathematical approach for optimization in the face of multiple influential criteria is the Analytic Hierarchy Process. "The analytic hierarchy process (AHP) provides the objective mathematics to process the inescapably subjective and personal preferences of an individual or a group in making a decision" (Schmoldt, 2001, pg. 15). This paper details the development of two categories of comprehensive BMP selection matrices expressing long-term pollutant removal performance and annual maintenance and operations cost respectively. Additionally, the AHP is applied in multiple scenarios to demonstrate the optimized selection of a single BMP among multiple competing BMP alternatives. Pairwise rankings of competing BMP alternatives are founded on a detailed literature review of the most popular BMPs presently implemented throughout the United States. / Master of Science

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