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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

Effect of oil prices on returns to alternative energy investments

Schmitz, Anthony. January 2009 (has links)
Thesis (M. S.)--Economics, Georgia Institute of Technology, 2010. / Committee Chair: Vivek Ghosal; Committee Member: Byung-Cheol Kim; Committee Member: Chun-Yu Ho; Committee Member: Tibor Besedes. Part of the SMARTech Electronic Thesis and Dissertation Collection.
12

The legal regimes governing marine renewable energy in England and Wales

Hamlyn, Victoria Jane January 2015 (has links)
This thesis involves an examination of the main international, regional and national legal regimes regulating marine renewable energy in England and Wales. Deriving from a complex patchwork of law and policy, developments have ensued in the absence of a distinct governing ‘legal regime’ and within a number of competing paradigms. This original synthesis attempts to identify lacunae, conflicts and connections within and between the span of legal genres that MRE evokes. Against a backdrop of climate change mitigation, the key findings show that despite the presence of political will for offshore renewable energies, MRE development faces a number of legal obstacles, all of which seek to protect other important public and private interests. Although predominantly satisfactory at the international level (international law of the sea), national private property rights, environmental protection laws and regulatory development controls each encompass particular legal incongruities that have the potential to act as barricades to development. This thesis discusses these issues and reaches conclusions as to potential areas for reform.
13

Infectivity and Physiological Effects of White Spot Syndrome Virus (WSSV) in Farmed Louisiana Red Swamp Crayfish (Procambarus clarkii)

Pace, Barcley Talon 20 April 2016 (has links)
The red swamp crayfish, Procambarus clarkii, represents an important aquaculture species responsible for over half of all commercial aquaculture profits in Louisiana. White spot syndrome virus (WSSV) is highly pathogenic and induces mass mortality in crustacean aquaculture operations worldwide. Crayfish lack the adaptive ability of the vertebrate immune system, and must depend on primitive, innate immune responses to combat viral infections. This study aims to investigate the dose-response of WSSV in P. clarkii and to examine viral-host interactions by examining the biochemical and immunological changes induced by WSSV infection in this species. Viable viral particles were isolated from naturally infected P. clarkii gill tissue, quantified using a novel digital PCR approach, and inoculated into P. clarkii to determine a median lethal dose (LD50) value of WSSV particles. After estimating an LD50 value, crayfish were inoculated at this nominal concentration of viral particles, and biological tissues were sampled across time to observe physiological and immunological changes throughout the course of WSSV infection. Antioxidant activity increased over time, while immunological gene expression was downregulated in the gill tissue of WSSV-infected crayfish. Knowledge of the infectivity of WSSV in native crayfish is of critical importance to the management of the commercial aquaculture industry in Louisiana. Examination of the viral-host interactions in crayfish can be used to facilitate future investigations towards WSSV prevention and management, and serve to develop the use of P. clarkii to model innate immune responses to WSSV infection in other decapod crustaceans. This is the first study to investigate dose-response and immunological changes induced by the Louisiana strain of WSSV in native crayfish.
14

A thermal charge system for variable electrical supplies from renewable sources

Macbeth, John Noel January 2013 (has links)
In a time of a fast growing renewable electricity generation sector, there are challenges regarding the integration of such generation with current transmission infrastructure. Such challenges include problems associated with the intermittent power output of renewable energy sources and the inability to control there output to meet varying electrical demand. Using part of this available energy for the provision of domestic heating loads may help bridge the gap between supply and demand. The use of intermittent electrical energy sources for charging water based thermal energy stores was identified as a research gap. This research project studies the use of intermittent electrical supplies from wind turbines for the provision of space heating and hot water in domestic buildings. It also addresses how solar water heating may be incorporated into the same thermal energy storage unit to create a hybrid system. This thesis outlines and analyses two charge strategies that may be used to promote stratification in water based thermal energy stores when adding intermittent electrical energy. The first makes use of multiple heating elements switched on in sequence (direct system) while the second uses buoyancy forces to take cool water from the bottom of the tank, pass it through the heating element and then place it back in at the top of the tank at a higher temperature (side-arm). The research method includes; 1) a simplified theoretical simulation of direct and side-arm configurations in the transient system simulation software (TRNSYS) to identify system performance when charged from wind and solar energy; 2) a detailed theoretical representation of the side-arm charge mechanism with a modulating valve for TRNSYS; 3) an empirical validation of the detailed theoretical model of the side-arm charge cycle. Outcomes from the simplified theoretical model indicate that the side-arm configuration may have benefits over the direct configuration due to reduced heat loss from the tank, reduced auxiliary energy consumption and increased solar collector performance. The detailed theoretical representation of the side-arm was calibrated using the empirical data gathered. From this, important parameters affecting the performance of the side-arm charge cycle are evaluated. These include the effects of tank height, operating temperature and the power range from the intermittent electrical supply. It is identified that the assumptions made in the simple model are not possible to reproduce in real life and that an analysis using the complex model must be made in order to evaluate any potential benefits of the side-arm over a direct configuration.
15

Biomass Gasification for Electricity Generation: An Integrated Approach for Development of Forest Residue-Based Projects in Rural India

Mishra, Anand 09 May 2016 (has links)
Biomass gasification is generally regarded as a promising technology for various advanced application in energy production. Biomass is the only carbon-based sustainable option among the renewable energy sources. This study is focused on fostering biomass gasification for electricity generation sector in India. The study addresses four broad aspects of biomass gasification for electricity generation - feedstock properties and gasification technology, policy and regulatory framework governing the sector, financial evaluation of electricity generation from biomass gasification, and feedstock supply. The study is divided in four chapters, each of which addresses one aspect of electricity generation through biomass gasification. Based on literature, first chapter presents a brief review of various properties of biomass feedstocks that are critical for gasification. It reviews the thermochemical conversion processes and the major issues related with biomass gasification with reference to some promising gasifier technology systems. Based on literature, second chapter examines the importance of national and sub-national policies supporting the development of bioenergy industry (including gasification for electricity generation) in various countries. The policies and instruments deployed globally are compared with those deployed in India. Third chapter posits a framework for conducting financial evaluation of a gasification power project. A case study of pine needle gasification power project in a remote rural area of Northern India is considered. In absence of historical data related with similar projects, a probability distribution for the Net Present Value (NPV) for the project is generated with the help of Monte Carlo Simulation. The simulation for NPV uses estimates of input variables from the data gathered from an existing pine needle based gasifier operating in the study area. Continuing with the case study, fourth chapter studies the villagers perspective on supplying pine needles to the gasification project. . A survey was administered to estimate villagers willingness to collect pine needles from the forests and supply it at a price to the gasification project. The willingness is modeled on demographic, livelihood, and latent factors, that are used in a Multinomial Logistic Regression Model to estimate the probability of households willingness to collect and supply pine needles to the project.
16

Vegetation Influences Microbial Community Structure and Methane Emissions in Southeastern Louisiana Wetlands

Rietl, Anthony Jason 11 May 2016 (has links)
Methane has a warming potential 28 times that of carbon dioxide and has been increasing in the Earths atmosphere since 1750. An understanding of the dynamics of methane emissions from natural sources is becoming increasingly important as we may need to mitigate emissions from these sources in the future to help reduce the effects of climate change. Wetlands are the single largest natural source of methane; however, little attention has been given to how plant species, biota, and interactions between above and belowground communities and microbial communities may affect methane emissions. First, microbial community structure and function was assessed for two salt marsh plant species, Spartina alterniflora and Juncus romerianus via bacterial, archaeal, and fungal gene fragments, and extracellular enzyme assays to determine whether wetland microbial communities were structured by vegetation, and whether communities were functionally different. Bacterial communities were differentiated by plant species in two of three sites, suggesting while vegetation likely plays a role in structuring these communities, specific site characteristics are likely of equal importance. Fungal communities were influenced more by site than vegetation, and archaeal communities appeared to be structured by vegetation. Second, four freshwater wetland plants (Sagittaria lancifolia, Panicum hemitomon, Eleocharis macrostachya, Echinochloa walteri) were transplanted and grown in large mesocosms, and clipped to differing heights under different nutrient treatments to detect changes in methane emissions, methanogen, and methanotroph communities. Methane emission rates were plant species specific, and a three way interaction indicated that species, nutrient level, and clipping level altered methane emission. Methanogen and methanotroph communities were not altered by the treatments. Lastly, densities of marsh periwinkle snails and southern ribbed mussels were manipulated inside fenced enclosures within a S. alterniflora salt marsh, and methane emissions and extracellular enzyme activities were measured over the course of a year. Southern ribbed mussels increased the emission of methane when present, but marsh periwinkle snail density had no effect. The data collected show that microbial community structure in wetlands are influenced by vegetation, that methane emission rates are plant species specific, and that southern ribbed mussels have the potential to increase methane emissions from S. alterniflora marshes.
17

Living on the Edge: An Assessment of the Habitat Use of Waterbirds in Estuarine Wetlands of Barataria Basin, LA

Patton, Brett Ashley 13 July 2016 (has links)
The wetlands of Louisiana are losing area at the rapid rate of 42.9 km2 yr-1 and the trend is expected to continue. This combined with expected sea-level rise will likely cause large shifts in vegetation and salinity regimes that will affect the wildlife species reliant on these ecosystems. Waterbirds serve as indicator species of ecosystem health in estuarine wetland habitats; therefore, these species are often the targets of wetland management goals in Louisiana. However, many proposed wetland restoration projects are focused primarily on social impacts with only a few specific waterbird species designated for management. The majority of these waterbird habitat-use studies in Louisiana wetlands have focused on waterfowl species and their abundance in wetland habitats during migration and winter. My overall objective was to compare habitat use of all waterbird taxa in fresh and saline estuarine wetland habitats. Additionally, I examined habitat use at finer spatial scales to assess a possible preference for marsh edge microhabitats when compared to open water and interior emergent vegetation. I also investigated waterbird associations with the environmental parameters of emergent and aquatic species composition, percentage of open water, and salinity. From July 2014 to December 2015, I compared waterbird density and species richness both spatially and temporally to assess habitat use. I found that species richness differed between fresh and saline habitats depending on the month, with the month of April having the greatest species richness. Waterbird density was greatest among edge microhabitat regardless of salinity type, and birds utilized this habitat up to 15 m from the edge. Density did not vary in open water plots in relation to salinity type. The relationships between environmental variables and species were significant (p=0.002) as well as relationships between guilds and environmental variables (p=0.002). These data will be useful in attempts to simulate the effects of wetland loss and salinity changes on habitat quality for waterbirds in coastal Louisiana, and will inform habitat restoration and management decisions for optimal waterbird use.
18

Developing a legal framework for promoting investment in renewable energy in the Nigerian power sector : an analysis of the design and implementation challenges

Oniemola, Peter Kayode January 2014 (has links)
This thesis investigates the role of support schemes to promote investment in renewable energy in the Nigerian power sector. The current situation does not favour investment in renewable energy. The argument developed by this thesis shows that the feed-in tariff (FIT) scheme is most suitable for encouraging investment in renewable energy in Nigeria. Drawing from legal analysis of international best practice and established FIT schemes in Germany and China, the research puts forward assertions that the FIT, with a design structure containing a fixed tariff for a guaranteed duration, tariff differentiation and degression, purchase obligation, guaranteed priority and guaranteed access to the grid, review measures and effective administration and implementation can encourage investment in renewable electricity in Nigeria. The thesis goes on to discuss how typical models of the FIT schemes used in the developed world need to be adapted to meet the existing challenges in the Nigerian electricity market if the FIT scheme is to be effective. The principal challenge is that consumers are unable to bear the cost of subsidies to investment in renewable energy. There are the concerns that purchasers of renewable electricity are not creditworthy. There are also general rule of law challenges which may lead to regulatory uncertainties and changes in support offered to investors. These require departures in design from the typical FIT models including those employed by Germany and China. The thesis proposes solutions to the particular difficulties in using an FIT scheme in Nigeria and concludes by providing a legal framework that includes suggested responses. It proposes that the FIT should be financed by the Nigerian state, by establishing a fund from the oil revenue account under the constitution. The risks of non-payment by the purchasers should be removed by establishing government guarantees backed by international financial institutions. Measures such as saving provisions in the law, stabilisation clauses in investment contracts and reliance on the provisions of bilateral investment treaties are important mechanisms that are proposed to check regulatory and investment uncertainties. The thesis presents a proposal for a legal framework for promoting renewable energy in the Nigerian power sector that incorporates these solutions.
19

Relative Resistance to Breaking of Pinus taeda L. and Pinus palustris

Garms, Cory Glenn 23 June 2016 (has links)
Patterns from hurricane damage give an indication that longleaf pine (Pinus palustris) is more windfirm than loblolly pine (Pinus taeda). Tree windfirmess has been attributed to many factors including species and material properties like wood strength and stiffness. Because longleaf pine wood is stronger and stiffer than loblolly pine wood, this study used static winching methodology to see if these properties account for differences in windfirmness by measuring bending force required to break stems (MMAX). Stress-strain diagrams were constructed for pulled trees to explore how they behave under increasing loads. Based on these diagrams, it appears that living trees can act as linear elastic materials as they experience increasing static lateral stress. As expected, longleaf pine stems were stiffer than loblolly pine wood in situ based on Youngs modulus of elasticity derived from these diagrams. Tree basal area was the best predictor of MMAX for both species, however, species had no effect on the maximum bending moment required to break tree stems of a given basal area for these trees under these conditions. The stiffness of the stems was higher for longleaf than loblolly as indicated by the modulus of elasticity, but the strength of the stems as indicated by the modulus of rupture was not significantly different between the species.
20

Efficacy and Feasibility of Alginate Bait for the Louisiana Commercial Blue Crab (Callinectes sapidus) Fishery

Clowes, ElizaBeth Lorraine 05 May 2016 (has links)
Louisiana leads all U.S. states in blue crab (Callinectes sapidus) landings, but high fuel and bait costs have hindered commercial fishing productivity of Louisiana in recent years. The primary baitfish, Atlantic menhaden (Brevoortia tyrannus), has steadily increased in price and decreased in availability, while crab prices remain low. To reduce costs for fishermen, an alternative bait was developed that incorporates shrimp waste into a semi-rigid alginate matrix. Lab testing and preliminary field tests show that shrimp-alginate bait may be a suitable alternative to menhaden for Louisiana crab fishermen. I evaluated bait performance by conducting field sampling to compare catch rates and longevity of standard baitfish and shrimp-alginate bait. I performed seasonal fishery-independent testing at three sites across Southern Louisiana from summer 2014 to spring 2015, and tested the bait on commercial crabbing boats throughout coastal Louisiana during peak crab season in 2015. Catch rates of shrimp-alginate were less than menhaden overall, however, bait performance changed with site and season, and did not significantly differ when I evaluated commercially relevant crab classes. Analysis of remaining bait quantity after fishing showed that shrimp-alginate remains intact as long, or longer, than standard baitfish during peak crab fishing from June through August. After testing shrimp-alginate bait in the field, I evaluated the economic feasibility of producing the bait with a partial budget supply line. With its current formulation, shrimp-alginate can only be produced at a cost lower than menhaden (currently $0.50/lb.) under optimal production scenarios, however, slight modifications that improve shelf life could dramatically decrease the cost of bait production. Findings from both field work and feasibility analysis show promise in the alternative shrimp-alginate bait with given improvements to catch rate efficacy and product storage.

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