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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.
11

De-Isolate: The Water-Food-Shelter Nexus

Lohani, Pratik 12 June 2020 (has links)
Climate change is a natural cyclical phenomenon and throughout our planet's existence there have been sustained periods of heating and cooling. These periods are often referred to as "ice ages" and "interglacials" respectively. Scientists attributed warms oceans and carbon dioxide released from the oceans as the reason for global warming in the past. However, human activities of the recent past, mainly the burning of fossil fuel has seen an amplification of global temperature at a scale never seen before. This unprecedented change in our environment, as per scientists will have adverse side effects and have a long-term impact in our world. The most likely effects of climate change will be; heatwave, drought, glacier melts, sea level rise, erratic precipitation and erosions depending on a particular geographical location. The socio-economic impact of climate change could be a severe one too. Heat and drought could have major impact on agriculture, food and forests. United Nations data released in 2016 suggests that by the year 2050, more than 50 percent of the world's population will face a dearth of fresh water sources. It is also predicted that water scarcity will most likely result in diseases, unemployment and poverty. Energy use is also likely to increase with the greater need for air conditioning in the summer and heating in the winters. In cases where a region can't cope with these consequences, mass migration in search of better conditions is also likely. Physical and economic infrastructure will be tested by severe weather, flooding, wildfires and other phenomena. Data published by the United Nations in 2014 estimated that more than 50% of the world's total population lives in the urban areas and soon that number is likely to increase to 60%. In conjunction with climate change, this will mean more strain on already stretched resources in urban ecosystems. Also, with data suggesting that many people will migrate due to unemployment and poverty because of climate change, it is highly likely urban regions will have to accommodate that population too. The intertwined nexus of freshwater shortage, food, water and energy security is an issue we are already grappling with today, which is likely to be exacerbated in the future. These issues cannot be reviewed and analyzed as separate phenomena, but rather as a single intertwined phenomenon. The solution of the problem, hence, should be treated as the same. / Master of Architecture / This thesis, initially, investigates the phenomenon of climate change, and the likely challenges that it might pose in the future. Sustained periods of heating and cooling is a natural cyclical process, but human activities of the recent past has amplified global warning. This, according to scientists, will impact earth in the long run, and will have climatological and socio economic consequences. Water scarcity, droughts, sea level rise, mass migration are identified as problems that could intensify in the future. At various regions across the world, we are already facing these issues at different scales. This thesis, hence identifies the most pertinent future challenges and simulates those with existing societal challenges. The aim of the thesis is to provide an integrated and holistic plan to address the issues at hand with a view that the approach would also adapt to and mitigate issues in the future. Natural cycles and resources are used as a model to develop a mechanism to create a built environment for a small, self sustaining community. The proposed design is a prototype for a particular climatic scheme, but could be altered to fit other climatic criteria. The scheme through, research, addresses contemporary societal needs and tries to provide a solution contingencies of climate change.
12

Triple Nexus – Assessing the HDP view of its functionality and implementation / Trippel Nexus - Bedömning av synen på dess funktionalitet och implementering från Humanitär-Utvecklings- och Fredsperspektivet

Gleisner, Daniel January 2021 (has links)
What are appropriate and relevant ways for collaboration and coordination between the three sections of aid work, humanitarian, development, and peace? This question has been topical for the aid community for decades when working in places where all three entities are present (Guinote, 2019). It is sometimes rejected, neglected but some times it is also considered and pursued (Hövelmann, 2020). This study aims to assess and analyze the arguments and breeding grounds for the triple nexus approached work in the DRC, the dynamics of promoting and receiving directions in a headquarters-field office relation exploring the challenges and opportunities between the three sections of HDP. Assessments have been done through conducting interviews remotely with people working on-site in the DRC at national or local offices and headquarters in Sweden and Central Europe. By interviewing eleven people with experience from all three HDP sectors, where a few people come from the donor sector, the goal has been to provide a broad picture of the aid community's perspective. This study's findings and inferences are related to funding structures where a more flexible funding system is requested. There are local involvement findings where signs through this study indicate local initiatives have been implementing the nexus approach for years. In environments such as presented in this study, of interrelating groups of people with differences in working culture, there are also challenges of clashing organizational principles, hegemonic approaches, and the ever topical issue of clear and relevant communication presented in the thesis. Through this assessment, power structures are pertinent to analyze to understand how the triple nexus approach can be further implemented. The agency theory will, in this study, be used as an eyeglass to assess these power relations.
13

Mitigating the impacts of droughts and heat waves at thermoelectric power plants in the United States

Cook, Margaret Allison 16 January 2015 (has links)
Recent droughts and heat waves have revealed the vulnerability of some power plants to effects from higher temperature intake water for cooling. Climate projections estimate higher air temperatures in future years, indicating that these problems could increase. This research seeks to understand the magnitude of influence that higher temperatures will have on power plant effluent water temperatures to quantify a power plant's exposure to risk of de-rating induced by low or warm cooling water availability. The objective of this analysis is to help policymakers and plant operators plan for future electricity supplies without damaging the natural environment of the cooling reservoirs and rivers. This objective is met via assessment of water constraints associated with current technology, policy, and environmental conditions in two river basins, the Gulf Coast Basin in Texas and the Upper Mississippi River Basin in the Midwestern United States. Risk of reduced operations at these power plants associated with thermal discharge limits is then assessed by estimating intake and effluent water temperatures and comparing these estimates to current restrictions. Of the thirty-three plants analyzed, none are estimated to exceed effluent temperature limits within the study period of 2015 to 2035. However, twelve power plants could face increasing intake temperatures, leading to potential issues with cooling efficiency. Fourteen plants could discharge slightly higher effluent temperatures, possibly influencing the ecosystem of the return water body upon discharge beyond today's impacts. To help with planning for future issues, this analysis also identifies many of the ways by which power plants mitigate issues with low water levels and high temperatures. Designing plants for potentially scarce water resources and making policies that protect water supplies and support energy resources could be beneficial in coming years. This research is intended to inform that objective. / text
14

Understanding the water-energy nexus: A case study of Ningxia

Li, Xinyue January 2014 (has links)
Using Ningxia Hui Autonomous Region in China as a case study, the thesis addresses the interconnectedness between water and energy and investigates the regional water-energy nexus to assess the coherence of relevant policies and to explore opportunities to achieve sustainable development. Ningxia is extremely scarce in water but abundant in coal. On one hand, the government sets stringent targets to conserve water; on the other hand, the region has ambitious plans to develop the water intensive coal and relevant industries. Based on current development status and policies, the water and energy systems are modeled by WEAP and LEAP, respectively. The regional water-energy nexus is mapped to reveal the interactions between water and energy sectors. From the water policies, it is estimated that the water demand would decrease slightly in 2015; from the energy policies, the energy demand and production would increase greatly. Through the nexus approach, it is found that while energy is abundant to satisfy the increasing demand by the water sector for production and supply, water, however, cannot support the aggressive energy development. The huge water deficit indicates the potential incoherence of current policies and the unsustainable development mode. Nevertheless, there are opportunities to secure resources sustainability. This thesis highlights the viability of the water-energy nexus approach for comprehensive cross-sectorial assessment in policy making and resource management.
15

Water-Energy Nexus Insight: Optimization of Source Waters for DBP Control

January 2011 (has links)
abstract: Local municipalities in the Phoenix Metropolitan Area have voiced an interest in purchasing alternate source water with lower DBP precursors. Along the primary source is a hydroelectric dam in which water will be diverted from. This project is an assessment of optimizing the potential blends of source water to a water treatment plant in an effort to enable them to more readily meet DBP regulations. To perform this analysis existing water treatment models were used in conjunction with historic water quality sampling data to predict chemical usage necessary to meet DBP regulations. A retrospective analysis was performed for the summer months of 2007 regarding potential for the WTP to reduce cost through optimizing the source water by an average of 30% over the four-month period, accumulating to overall treatment savings of $154 per MG ($82 per AF). / Dissertation/Thesis / M.S. Civil and Environmental Engineering 2011
16

Evaluating and Avoiding Risk Tradeoffs in Water Treatment

Gingerich, Daniel Beryl 01 August 2017 (has links)
Treating water in order to reduce human and environmental risks requires the use of electricity and chemicals, the generation of which creates emissions of air pollutants such as NOx, SO2, PM2.5, and CO2. Emissions of air pollutants establishes a health and environmental risk tradeoff between air and water pollution. Addressing air-water tradeoffs by adopting a one environment framework requires new methods for quantifying these tradeoffs, new technologies to minimize air-water tradeoffs, and new tools for decision makers to incorporate these tradeoffs into compliance decisions. In my thesis, I develop methods for quantifying damages from air emissions associated with water treatment; assess the feasibility of forward osmosis (FO), a technology which holds the promise to avoid air-water tradeoffs; and create a tool to holistically assess compliance with air and water emission standards for coal-fired power plants (CFPPs). I start my thesis by creating a method to quantify the damages caused by the air emissions that resulting from the treatment of drinking water (Chapter 2), municipal wastewater (Chapter 3), and flue gas desulfurization (FGD) wastewater (Chapter 4). These studies use life-cycle models of energy and chemical consumption for individual water treatment unit processes in order to estimate embedded emissions of criteria air pollutants and greenhouse gasses per cubic meter of treated water. Damages from these additional air emissions are assessed and incorporated into benefit-cost analyses. I find that for drinking water rules, the net benefit of currently implemented rules remains positive but the promises of net benefits for some proposed rules are conditional on the compliance technology that is selected. For municipal wastewater, I find that while there are ~$240 million (in 2012 USD) benefits in air emission reduction from installing biogas-fueled electricity generation nationwide, there are several states where biogas-fueled electricity creates more air emissions than it displaces. For FGD wastewater treatment, I find that complying with the effluent limitation guidelines has an expected ratio of benefits to cost of1.7-1.8, with damages concentrated in regions with large chemical manufacturing industries or electricity grids that are heavily reliant on coal. In the next part of the thesis, I assess the techno-economic feasibility of power plant waste heat driven FO to reduce the air emissions associated with FGD wastewater treatment. In Chapter 5, I assess the quantity, quality and the spatial and temporal availability of waste heat from US coal, nuclear, and natural gas power plants. I find that while 18.9 billion GJ of potentially recoverable waste heat is discharged into the environment, only 900 million GJ of that heat is from the flue gas and is at a temperature high enough to drive water purification using forward osmosis (FO). In Chapter 6, I build a model of FO to assess its thermal energy consumption and find that the 900 million GJ of waste heat produced at coal and natural gas power plants is sufficient to meet their boiler feedwater and FGD wastewater treatment needs. In Chapter 7, I incorporate cost into the energy consumption model of FO, and conclude that treatment of FGD and gasification wastewater using waste heat driven FO is economically competitive with mechanical vapor recompression. In Chapter 8, I create an energy-balance model of a CFPP and nine environmental control technologies for compliance with FGD wastewater and carbon capture regulations. I use this model to maximize plant revenue at the National Energy Technology Laboratory’s 550 MW model CFPP without carbon capture. I find that revenue is maximized by using residual heat for water treatment or carbon capture. If both carbon capture and zero liquid discharge water treatment regulatory standards are in place, I conclude that the plant maximizes revenue by allocating residual heat and steam to amine-based carbon capture and electricity to mechanical vapor recompression for FGD wastewater treatment.
17

The Design and Fabrication of the Multistage-Membrane Distillation Device Integrated with Solar Cell for Simultaneous Water and Electricity Production via Sunlight

Wang, Wenbin 11 1900 (has links)
Freshwater scarcity and clean energy shortage are two grand challenges to global sustainable development. The inextricably interconnected water-energy nexus is being increasingly felt globally owing to the massive water used for electricity generation and huge amount of energy consumed in water desalination. This dissertation investigated the utilization of the waste heat of the solar cell to produce fresh water. This is achieved by constructing a multistage membrane distillation device (MSMD) at the backside of the solar cell to efficiently utilize its heat and it is capable of recycling the latent heat of the vapor condensation in each distillation stage. The first generation photovoltaic-membrane distillation (PV-MD) device exhibits a clean water production rate of 1.64 kg/m2 h with the solar cell temperature of 58 oC in a 3-stage device under one-sun radiation. However, some concentrated seawater can be produced from the PV-MD owing to its cross-flow design. To this end, an evaporative crystallizer is designed beneath the PV-MD, which can reuse the low-grade latent heat of vapor condensation in the last stage of the MSMD to evaporate the produced concentrated seawater, realizing zero liquid discharge. In addition, a theoretical model was also established to enhance the clean water production rate and reduce the solar cell temperature, which guides us to select a hydrophobic membrane with a thickness of 0.1 mm and porosity of 0.86 to fabricate the second generation photovoltaic-membrane distillation-evaporative crystallizer (PV-MD-EC) device. We experimentally demonstrate that a 5-stage PV-MD-EC device can desalinate seawater at a rate of ~2.45 kg m-2 h-1 with a lower solar cell temperature of ~48oC. The electricity generation efficiency of the solar cell is also enhanced by ~8% owing to its reduced temperature. A trade-off exists between the clean water production performance and material cost of the MSMD because a higher energy efficiency is at the expense of more stages applied. A low-cost and highly flexible 8-stage paper-based MSMD (P-MSMD) is further designed and fabricated and it showed a clean water production rate of 3.61 kg/m2 h for seawater desalination. This work sheds light on the design and fabrication of a composite system capable of achieving the simultaneous production of electricity and clean water with solar energy as an only energy source. Owing to their low barrier of entry, the devices reported in this dissertation are well suited to provide off-grid electricity and freshwater in a decentralized manner for point of consumption locations especially off-grid communities and communities with small- to medium-sized population even with challenging economic conditions.
18

Developing a citizen science framework for water resources Protection to facilitate operationalization of resource Directed measures at catchment level, South Africa

Nzama, Stanley Mvuselelo January 2021 (has links)
Philosophiae Doctor - PhD / Maintenance of water resources protection practice for water availability, uninterrupted water utilization, and for ecosystem integrity is critical for sustainable achievement of resource security for all. Therefore, operationalization of water resource protection strategies such as resource directed measures, especially at catchment level where water resources utilization takes place is critical. The main aim of the current study was to develop a citizen science framework for operationalization of resource directed measures at catchment level. Such a framework used a nexus approach, and its development was guided by the principles of socio-ecological model from a systems thinking perspective. This demonstrated importance of resource directed measures which are accepted as relevant policy implementation strategies towards improved and integrated water resources management practice at catchment level, where local citizens become part of such practice. Local operationalization of resource directed measures provides a basis for practical policy implementation at catchment level, thereby informing decisions taken on water resources protection and sustainable water use for several purposes. It provides an understanding of how policies which are formulated for water resources protection purposes influence land use activities and other non-land use activities to ensure water availability for current and future generations. Furthermore, localized operationalization of resource directed measures facilitates ecological ecosystems protection such that goods and services derived from such ecosystems are sustained. The research problem of the current study was a lack of available and feasible plan for resource directed measures practice at catchment level which has a direct influence on the continued water quality deterioration and unsustainable utilization of water resources. This study argued that a citizen science framework needed to be developed and such a plan must be informed by science-policy interface that is practical, reflective and must consider the nexus approach using the concept of citizen science in order to improve the practice of resource directed measures at local level in an acceptable manner by practitioners.
19

Economy of Scale of Energy Intensity in Aquifer Storage and Recovery (ASR)

Rapp, Alyson Haley 07 December 2023 (has links) (PDF)
More water utilities are adopting Aquifer Storage and Recovery (ASR) to balance long-term water supply and demand. Due to large implementation and operation costs, ASR projects need to be optimized, particularly for energy use, which is a major operating expense. This study examines the relationships among energy use, recharge, and recovery at two ASR projects in the western United States. The major finding is an economy of scale for recovery processes, but not for gravity-fed recharge processes. The economy of scale found is as follows: the energy intensity recovered decreases with volume. This suggests it is more energy-efficient to recover large volumes of water in one interval instead of recovering smaller volumes at more frequent intervals. The H2Oaks recovery process experienced a 78% decrease in energy intensity from 0 to 50,000 m^3 recovered, while the Sand Hollow site experienced a 43% decrease in energy intensity from 0 to 50,000 m^3 recovered. Statistical analyses of the recovery process showed p values lower than 0.0001, R^2 values between 0.43 and 0.57, and a RMSE value between 0.55 and 2.1, indicating the presence of a moderate correlation between energy and volume. This economy of scale has been observed in multiple instances in water and wastewater treatment. This finding not only has applications to ASR but also all recovery or recharge wells, whether or not they are paired with each other. Furthermore, this study confirms the need for more reliable and accessible energy data to fully understand the implications of the energy–water nexus.
20

Minskar spinal rörelsebegränsning tiden på olycksplats? : En jämförelsestudie mellan spinal rörelsebegränsning och spinal immobilisering

Stridsberg, Daniel, Asplid, Matilda January 2023 (has links)
Fem miljoner människor dör varje år relaterat till trauma. Detta gör trauma till den sjunde vanligaste dödsorsaken där främst yngre drabbas. Den trubbiga skademekanismen utgör 90% av fallen, exempelvis genom trafikolyckor och fall. Av dessa drabbas 2–4% av spinala ryggskador, vilket är en fraktur på nacke- eller ryggkotpelaren. Av de som drabbas av lider årligen cirka 400 patienter innan de anländer till sjukhus. Innan 2019 immobiliserades samtliga patienter enligt standardiserat omhändertagande. Det nya vårdsystemet med spinal rörelsebegränsning tillåter ett personcentrerat omhändertagande. Studiens primära hypotes är att tid på skadeplats har minskat efter införandet av spinal rörelsebegränsning. Sekundära hypoteser är att 1) Det är färre patienter som spinaltrörelse begränsas år 2021 än patienter som spinalt immobiliserades år 2018; 2) de patienter som spinaltrörelse begränsades hade en lägre puls och blodtryck samt en högre syremättnad än de som immobiliserades. Metoden är retrospektiv och görs via journalgranskning med en kvantitativ ansats. Resultatet visar att det inte finns någon signifikant skillnad i tiden som ambulansen spenderar på olycksplatsen mellan de båda åren. Det finns inte heller någon signifikant skillnad på påverkan av patientens vitalparametrar. Däremot begränsades andelen patienter som erhöll spinal rörelsebegränsning 2021 jämfört med andelen som immobiliserades 2018. Med hjälp av det nya bedömningssystemet frias fler patienter från misstanke om spinal skada på olycksplatsen jämfört med det standardiserade omhändertagande som tidigare användes. Bedömningsverktyget NEXUS som används vid misstanke om spinal skada utgår från sjuksköterskans bedömning men det behövs tydliga riktlinjer, vana och mer träning för att på bästa sätt tillämpa åtgärder för eventuell spinal rörelsebegränsning.

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