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Hydrothermal Organic Reduction and DeoxygenationJanuary 2018 (has links)
abstract: Organic reactions in natural hydrothermal settings have relevance toward the deep carbon cycle, petroleum formation, the ecology of deep microbial communities, and potentially the origin of life. Many reaction pathways involving organic compounds under geochemically relevant hydrothermal conditions have now been characterized, but their mechanisms, in particular those involving mineral surface catalysis, are largely unknown. The overall goal of this work is to describe these mechanisms so that predictive models of reactivity can be developed and so that applications of these reactions beyond geochemistry can be explored. The focus of this dissertation is the mechanisms of hydrothermal dehydration and catalytic hydrogenation reactions. Kinetic and structure/activity relationships show that elimination occurs mainly by the E1 mechanism for simple alcohols via homogeneous catalysis. Stereochemical probes show that hydrogenation on nickel occurs on the metal surface. By combining dehydration with and catalytic reduction, effective deoxygenation of organic structures with various functional groups such as alkenes, polyols, ketones, and carboxylic acids can be accomplished under hydrothermal conditions, using either nickel or copper-zinc alloy. These geomimetic reactions can potentially be used in biomass reduction to generate useful fuels and other high value chemicals. Through the use of earth-abundant metal catalysts, and water as the solvent, the reactions presented in this dissertation are a green alternative to current biomass deoxygenation/reduction methods, which often use exotic, rare-metal catalysts, and organic solvents. / Dissertation/Thesis / Doctoral Dissertation Chemistry 2018
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Viabilidade energética e econômica da incineração de resíduo sólido urbano considerando a segregação para reciclagem /Poletto Filho, José Antonio. January 2008 (has links)
Orientador: Celso Luiz da Silva / Banca: Geraldo Luiz Palma / Banca: Antonio Moreira dos Santos / Resumo: A exploração abusiva da energia originada de fontes não renováveis traz danos irreversíveis ao ambiente. O Brasil é dependente dos derivados do petróleo e das hidroelétrica. Diante desse contexto é necessário um estudo sobre outras fontes alternativas. Conciliar a geração de energia com possibilidade também de mitigar o impacto da geração de lixo seria resolver dois problemas de uma só vez. O objetivo do presente trabalho é analisar a recuperação de energia do Resíduo Sólido Urbano (RSU) através do processo de incineração. Leva em consideração a tendência atual de segregação (separação) de plásticos, papel e papelão, vidro e metais, e sua influência nos fluxos de massa e energia no sistema de incineração de RSU. Para o seu desenvolvimento foram utilizadas informações relativas à geração do RSU da cidade de Bauru e o software Combust. Os resultados obtidos permitiram estimar o poder calorífero teórico do RSU típico e também deste resíduo quando se considera a separação de papel/papelão e plásticos para fins de reciclagem. / Abstract: The abusive exploration of the originated energy of no-renewable sources brings irreversible damages to the environment. In Brazil, it is dependent mainly of the derived or petroleum and of the hydroelectric ones. With base in that fact, the subject of the sources of energy is subject on the agenda globally. On the other hand, the wastes generation and the consequent environmental contamination, comes increased in an alarming way. Conciliate the generation of energy with possibility of mitigating the impact of the wastes generation it would be to solve two problems of only one time. The objective of the present work is to analyze the recovery of energy of the Municipal Solid Wastes (MSW) through of the incineration process. It considers the actual tendency of segregation of plastics, paper and cardboard, glass and metals, and your influences in the mass and energy flows in the incineration system of MSW. For the development of thiw work were used relative information to the MSW generation of Bauru city and the Combust software. The obtained results allowed esteeming the Theoretical Calorific Power of MSW typical and also of this residue when it is considered the paper / cardboard and plastics separation for recycling. / Mestre
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Investigation of Heat-driven Polygeneration and Adsorption Cooling SystemsJanuary 2018 (has links)
abstract: Just for a moment! Imagine you live in Arizona without air-conditioning systems!
Air-conditioning and refrigeration systems are one of the most crucial systems in anyone’s house and car these days. Energy resources are becoming more scarce and expensive. Most of the currently used refrigerants have brought an international concern about global warming. The search for more efficient cooling/refrigeration systems with environmental friendly refrigerants has become more and more important so as to reduce greenhouse gas emissions and ensure sustainable and affordable energy systems. The most widely used air-conditioning and refrigeration system, based on the vapor compression cycle, is driven by converting electricity into mechanical work which is a high quality type of energy. However, these systems can instead be possibly driven by heat, be made solid-state (i.e., thermoelectric cooling), consist entirely of a gaseous working fluid (i.e., reverse Brayton cycle), etc. This research explores several thermally driven cooling systems in order to understand and further overcome some of the major drawbacks associated with their performance as well as their high capital costs. In the second chapter, we investigate the opportunities for integrating single- and double-stage ammonia-water (NH3–H2O) absorption refrigeration systems with multi-effect distillation (MED) via cascade of rejected heat for large-scale plants. Similarly, in the third chapter, we explore a new polygeneration cooling-power cycle’s performance based on Rankine, reverse Brayton, ejector, and liquid desiccant cycles to produce power, cooling, and possibly fresh water for various configurations. Different configurations are considered from an energy perspective and are compared to stand-alone systems. In the last chapter, a new simple, inexpensive, scalable, environmentally friendly cooling system based on an adsorption heat pump system and evacuated tube solar collector is experimentally and theoretically studied. The system is destined as a small-scale system to harness solar radiation to provide a cooling effect directly in one system. / Dissertation/Thesis / Doctoral Dissertation Mechanical Engineering 2018
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A Comparative Study of Quasi-solid Nanoclay Gel Electrolyte and Liquid Electrolyte Dye Sensitized Solar CellsJanuary 2012 (has links)
abstract: Dye sensitized solar cells (DSSCs) are currently being explored as a cheaper alternative to the more common silicon (Si) solar cell technology. In addition to the cost advantages, DSSCs show good performance in low light conditions and are not sensitive to varying angles of incident light like traditional Si cells. One of the major challenges facing DSSCs is loss of the liquid electrolyte, through evaporation or leakage, which lowers stability and leads to increased degradation. Current research with solid-state and quasi-solid DSSCs has shown success regarding a reduction of electrolyte loss, but at a cost of lower conversion efficiency output. The research work presented in this paper focuses on the effects of using nanoclay material as a gelator in the electrolyte of the DSSC. The data showed that the quasi-solid cells are more stable than their liquid electrolyte counterparts, and achieved equal or better I-V characteristics. The quasi-solid cells were fabricated with a gel electrolyte that was prepared by adding 7 wt% of Nanoclay, Nanomer® (1.31PS, montmorillonite clay surface modified with 15-35% octadecylamine and 0.5-5 wt% aminopropyltriethoxysilane, Aldrich) to the iodide/triiodide liquid electrolyte, (Iodolyte AN-50, Solaronix). Various gel concentrations were tested in order to find the optimal ratio of nanoclay to liquid. The gel electrolyte made with 7 wt% nanoclay was more viscous, but still thin enough to allow injection with a standard syringe. Batches of cells were fabricated with both liquid and gel electrolyte and were evaluated at STC conditions (25°C, 100 mW/cm2) over time. The gel cells achieved efficiencies as high as 9.18% compared to 9.65% achieved by the liquid cells. After 10 days, the liquid cell decreased to 1.75%, less than 20% of its maximum efficiency. By contrast, the gel cell's efficiency increased for two weeks, and did not decrease to 20% of maximum efficiency until 45 days. After several measurements, the liquid cells showed visible signs of leakage through the sealant, whereas the gel cells did not. This resistance to leakage likely contributed to the improved performance of the quasi-solid cells over time, and is a significant advantage over liquid electrolyte DSSCs. / Dissertation/Thesis / M.S.Tech Engineering 2012
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Angle of Incidence and Non-Intrusive Cell Quantum Efficiency Measurements of Commercial Photovoltaic ModulesJanuary 2013 (has links)
abstract: This is a two-part thesis: Part 1 of this thesis tests and validates the methodology and mathematical models of the International Electrotechnical Commission (IEC) 61853-2 standard for the measurement of angle of incidence (AOI) effects on photovoltaic modules. Flat-plate photovoltaic modules in the field operate under a wide range of environmental conditions. The purpose of IEC 61853-2 is to characterize photovoltaic modules' performance under specific environmental conditions. Part 1 of this report focuses specifically on AOI. To accurately test and validate IEC 61853-2 standard for measuring AOI, meticulous experimental setup and test procedures were followed. Modules of five different photovoltaic technology types with glass superstrates were tested. Test results show practically identical relative light transmission plots for all five test modules. The experimental results were compared to theoretical and empirical models for relative light transmission of air-glass interface. IEC 61853-2 states "for the flat glass superstrate modules, the AOI test does not need to be performed; rather, the data of a flat glass air interface can be used." The results obtained in this thesis validate this statement. This work was performed in collaboration with another Master of Science student (Surynarayana Janakeeraman) and the test results are presented in two masters theses. Part 2 of this thesis is to develop non-intrusive techniques to accurately measure the quantum efficiency (QE) of a single-junction crystalline silicon cell within a commercial module. This thesis will describe in detail all the equipment and conditions necessary to measure QE and discuss the factors which may influence this measurement. The ability to utilize a non-intrusive test to measure quantum efficiency of a cell within a module is extremely beneficial for reliability testing of commercial modules. Detailed methodologies for this innovative test procedure are not widely available in industry because equipment and measurement techniques have not been explored extensively. This paper will provide a literature review describing relevant theories and measurement techniques related to measuring the QE of a cell within a module. The testing methodology and necessary equipment will be described in detail. Results and conclusions provide the overall accuracy of the measurements and discuss the parameters affecting these measurements. / Dissertation/Thesis / M.S.Tech Technology 2013
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Optimal Capacity and Location Assessment of Natural Gas Fired Distributed Generation in Residential AreasJanuary 2014 (has links)
abstract: With ever increasing use of natural gas to generate electricity, installed natural gas fired microturbines are found in residential areas to generate electricity locally. This research work discusses a generalized methodology for assessing optimal capacity and locations for installing natural gas fired microturbines in a distribution residential network. The overall objective is to place microturbines to minimize the system power loss occurring in the electrical distribution network; in such a way that the electric feeder does not need any up-gradation. The IEEE 123 Node Test Feeder is selected as the test bed for validating the developed methodology. Three-phase unbalanced electric power flow is run in OpenDSS through COM server, and the gas distribution network is analyzed using GASWorkS. The continual sensitivity analysis methodology is developed to select multiple DG locations and annual simulation is run to minimize annual average losses. The proposed placement of microturbines must be feasible in the gas distribution network and should not result into gas pipeline reinforcement. The corresponding gas distribution network is developed in GASWorkS software, and nodal pressures of the gas system are checked for various cases to investigate if the existing gas distribution network can accommodate the penetration of selected microturbines. The results indicate the optimal locations suitable to place microturbines and capacity that can be accommodated by the system, based on the consideration of overall minimum annual average losses as well as the guarantee of nodal pressure provided by the gas distribution network. The proposed method is generalized and can be used for any IEEE test feeder or an actual residential distribution network. / Dissertation/Thesis / M.S. Electrical Engineering 2014
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Mutational analysis of geopilin function in Geobacter sulfurreducensRichter, Lubna V 01 January 2011 (has links)
Geobacter sulfurreducens possesses type IV pili that are considered to be conductive nanowires and a crucial structural element in biofilm formation, enabling electron transfer to insoluble metal oxides in anaerobic sediments and to graphite anodes in microbial fuel cells. The molecular mechanism by which electrons are transferred through the nanowires to the electron acceptor is not fully understood. Prior to the work described in this thesis, the gene (pilA) encoding the structural pilus subunit had been identified, but little was known about the functional translation start codon, the length of the mature secreted protein, or what renders the pili conductive. Using mass spectrometry, I found that a tyrosine residue (Y32) near the carboxyl terminus of the mature PilA protein is posttranslationally modified by attachment of glycerophosphate. I studied the significance of Y32 for biofilm formation on various surfaces and for growth of G. sulfurreducens with insoluble electron acceptors. A mutant in which Y32 was replaced by phenylalanine lacked the glycerophosphate; biofilm formation on graphite surfaces was severely diminished and current production in microbial fuel cells was initiated only after a long lag phase. Moreover, cells with Y32F mutation in the pilA gene exhibited growth deficiency when Fe(III) oxide was the sole electron acceptor. My data confirm the role of G. sulfurreducens pili in biofilm formation and electron transfer to Fe(III) oxide and identify an amino acid in the PilA protein that is essential for these two processes. I also confirmed the existence of two functional translation start codons for the pilA gene and identified two isoforms (short and long) of the PilA preprotein by series of genetic complementation experiments. The short PilA isoform is found predominantly in an intracellular fraction, and seems to stabilize the long isoform and influence the secretion of several outer surface c-type cytochromes. The long PilA isoform, on the other hand, is required for secretion of PilA to the outer surface of the cell, a process that requires co-expression of pilA and the nine genes on its 3' side. The long isoform is essential for biofilm formation on various surfaces, for optimum current production in microbial fuel cells, and for growth on insoluble Fe(III) oxide. This study provides new insight concerning the function and biogenesis of Geobacter type IV PilA, as well as a foundation for further research that will be conducted on microbial nanowires.
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Supporting energy transitions and miscanthus program development at the University of IowaLain, Kayley Christina 01 May 2017 (has links)
Miscanthus is a highly productive, low-input biofuel crop that supports agricultural diversification with improved performance for climate commitment, energy security, and water quality over first generation biofuels. Despite its high performance, no local or regional markets for the feedstock have formed in North America, and current climate-based productivity assessment methods lack the information farmers and decision-makers need to establish commercial scale bioenergy markets, programs, and thermal co-firing plans. This study develops a Miscanthus Suitability Rating and a transferable field-scale siting method, applied at 10 m resolution across the State of Iowa to assess miscanthus production potential and identify individual farms that are highly suitable for large-scale miscanthus cultivation while maintaining a majority of existing row cropping acreage. Results show that highly suitable fields within 50 miles (84 km) of each of Iowa’s coal-fired electrical generating units (EGUs) can displace up to 43% of current coal consumption. Every EGU in Iowa has land resource to produce local miscanthus to co-fire with other solid fuels at industry-leading levels without significantly impacting local row crop production. Seven of the state’s smaller facilities could even operate exclusively on local miscanthus with advancements in densification technology. The energy evaluation tool developed in this work estimates the energy return on investment (EROI) of Iowa miscanthus for existing thermal generation facilities between 37 and 59, depending on transportation requirements and chemical field applications. This transition would diversify local agribusiness and energy feedstocks, reduce greenhouse gas emissions and provide a sustainable, dispatchable, in-state fuel source to complement wind and solar energy.
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DEVELOPING A METHOD FOR THE ELECTROCEHMICAL CHARACTERIZATION OF NOVELNITROGEN-DOPED CARBONACEOUS CATALYSTS FOR CARBON DIOXIDE REDUCTIONKaplan, Samuel 01 September 2021 (has links)
No description available.
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Positive Energy: Investigating Alternative Energy Use in Middle SchoolsPrice, Jamie H., Abel, Maranda O., Varney, Amanda, Wexler, David 01 January 2018 (has links)
This chapter introduces a project-based learning lesson that integrates science, English language arts (ELA), and math through a study related to energy sources. Throughout the lesson, students are engaged in a real-world problem of determining the impact of a population on energy resources and discovering ways to build greener, more energy-efficient schools for students of the future. Within this chapter, the authors present a proposed project timeline that teachers can use for implementation within their own classrooms, including an entry event to engage students in the mission of the project. A connection between science, ELA, and math practices is addressed in order to provide students with an opportunity to understand the correlation between all three subject areas. Suggested teaching and learning tasks focused on the driving question of the project and related to all three subject areas are presented along with suggestions for a culminating product and assessment of student learning.
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