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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

Deposit Formation of Deoxygenated JP-8 Fuel with Added Hydroperoxides

Kerr, Kristen Rita January 2013 (has links)
No description available.
12

Effect of Fuel Chemical Composition on Pyrolytic Reactivity and Deposition Propensity under Supercritical Conditions

McMasters, Brian Philip 05 June 2014 (has links)
No description available.
13

Study of Hydrocarbon and Carbonyl Compound Emissions from Combustion of Biodiesel Blends using Plasma and Swirl Stabilized Combustors

Sinha, Amit 20 October 2016 (has links)
No description available.
14

The Future of Advanced Bio-Jet Fuel

Blochel, Amanda January 2017 (has links)
The aviation industry is growing rapidly and the carbon dioxide emissions from the industry are following in the same manner. Biofuels made from edible feedstock have had an impact on lowering the emissions but at the same time an impact on increasing food prices. There are a few alternative fuels on the market today (TF-SPK, HEFA-SPK) which work in a blend with the petroleum based fuels, reducing the emissions from the aircrafts. Biofuels from next generation biomass, also called advanced biomass, such as algae and lignin, seem likely to be a good substitute for the first generation biofuels. The advanced biofuels are relatively costly to produce. This is due to the many steps in the production process, which restricts the usage of these sorts of fuels in the aviation industry. There are some problems associated with a jet fuel produced from 100% biomass. This is because the jet fuel produced from biomass differs from the jet fuels used today, making it unsafe to use in modern day airplane engines. That is why it is important to find an alternative jet fuel based on biomass that has the same characteristics as the conventional jet fuel, to be able to use the same transportation and engines that are in use today. Otherwise the high cost of advanced bio-jet fuels will make them unusable.
15

Jet Fuel Hedging and Modern Financial Theory in the U.S. Airline Industry

Schweitzer, Brandon Lee 01 January 2017 (has links)
To counter the problem of the volatility of jet fuel prices within the United States, many financial managers of U.S. airlines use hedging as a financial tool to mitigate the risk of exposure to market price volatility. However, their efforts often lead to financial distress for their airlines. The purpose of this qualitative grounded theory study was to explore U.S. airline managers' use of financial hedging to reduce the risk of exposure from the volatility of jet fuel prices. The conceptual framework was Simkowitz's theory of modern finance, which concerns debt policy, dividend policy, and investment policy as they relate to financial decision making by upper management. The research questions addressed when, why, and how U.S. airline financial managers would consider the use of hedging as a financial tool to mitigate the risk in the purchase of jet fuel at times of lower jet fuel prices. Interviews with a purposive sample of 20 U.S. airline financial managers provided data for analysis and theory development of jet fuel hedging utilization in the U.S. airline industry. Data analysis using the constant comparative method enabled the development of a theory of jet fuel hedging utilization. Participants reported using over-the-counter derivatives purchasing strategies as a form of hedging to protect their airlines against spikes in jet fuel prices on the open market. Using study findings, managers may be able to reduce jet fuel operating costs in the U.S. airline industry. Implications for positive social change include potentially higher profits and more jobs as well as lower consumer prices.
16

Biojetbränslen; Förutsättningar, möjligheter ochutmaningar med framtida flyg / Bio jet fuel; Prerequisites, possibilities andchallenges for future aviation

Henningsson, Jesper, Brewitz, Magnus January 2019 (has links)
Idag pågår en omfattande omställning till förnyelsebara energikällor för att minska negativa effekter orsakade av växthusgaser. Sverige har som mål att vara fossilfritt 2045. Biojetbränsle, jetbränsle framställt från biomassa, är det enda rimliga förnyelsebara alternativet för flyget meddagens teknik. Sverige har goda tillgångar till potentiellt råmaterial för framställning av biojetbränsle från skogsbruket. Fem certifierade framställningsmetoder kartlades och analyserades genom litteraturstudier och intervjuer med experter inom såväl flyg som bränsle för att fastställa deras lämplighet för svensk biojetbränsleproduktion. Förutsättningar, möjligheter, utmaningar och drivkrafter kopplade till framställning av biojetbränsle identifierades. Framställningsmetoderna analyserades med hjälp aven Pugh-matris där framställningsmetoderna jämfördes mot varandra utifrån faktorer som bedömdes relevanta. Analysen indikerade att framställningsmetoderna Alcohol to Jet och Fischer-Tropsch var bäst lämpade för svenska förhållanden, mycket tack vare möjligheten att användaskogsråvara som råmaterial. Certifieringsprocesser och certifierade bränslen identifierades. Nya biojetbränslen måste genomgå en rigorös certifieringsprocess och uppfylla hårda krav för att kunna certifieras enligt standarden ASTM D7566. Certifieringsprocessen för biojetbränslen visade sig vara en internationellt gemensam process, som en koalition av motortillverkare, flygbolag, myndigheter med flera, beslutat skall vara standard för framtagandet av framtida biojetbränslen. Återstående arbete för att kvalificera försvarsmaktens flygplattformar för drift med biojetbränsle därav utreddes. Det konstaterades att tillverkarna av flygfarkoster och motorer avgör huruvida de är godkända för drift med biojetbränsle. Till följd av högre kostnader för framställning av jetbränsle från biomassa än från råolja är tydliga policys och långsiktiga styrmedel en grundläggande förutsättning för att framställning av biojetbränsle ska lyckas. Tillgång till tillräckliga mängder hållbart råmaterial samt effektiva försörjningskedjor är exempel på utmaningar. Möjligheterna för biojetbränsle visade sig exempelvis vara tillvaratagandet av skadad skog. / There is an ongoing, extensive move towards renewable energy sources in order to reduce negative effects caused by greenhouse gases. Sweden aims to be completely fossil free by 2045. Bio jet fuel, jet fuel produced from biomass, is the only plausible renewable alternative for aviation with today's technology. Sweden has a good supply of potential feedstock for production of bio jet fuel from its forest industry. Five certified production routes were charted and analysed through literature studies and interviews with experts from the aviation and fuel field. Prerequisites, opportunities, challenges and drivers associated with bio jet fuel production were identified. The production routes were analysed with the help of a Pugh-matrix, they were compared to each other by factors that were deemed relevant. The analysis indicated that the routes Alcohol to Jet and Fischer Tropsch were most suitable for Swedish conditions, in large part due to the possibility of using forest products as feedstock. Certification processes and certified bio jet fuel were identified. New bio jet fuels have go through arigouros certification process and meet high set standards in order to be certified by the standard ASTM D7566. The certification process for bio jet fuels turned out to be an internationally agreed upon process that a coalition of OEM (Original Equipment Manufactures), airlines, authorities etc. agreed upon to be the standard for certification of future bio jet fuel. Which steps are required to approve aircraft in Sweden's armed forces for use with bio jet fuel were investigated. It was found that it is up to the OEM to decide if an aircraft is approved to run on bio jet fuel. Due to higher costs associated with production of jet fuel from biomass than from crude oil, clear policies and long term legislation are fundamental for success. Access too sufficient sustainable feedstock and effective supply chains are example of challenges that need to be addressed. The possibility of using damaged forest that would otherwise go to waste is one opportunity with bio jet fuel production.
17

Commodity Risk Management in The Airline Industry : A study from Europe

Havik, Jonathan, Stendahl, Emil, Soteriou, Andreas January 2016 (has links)
The airline industry is a major user of jet fuel and this constitutes a large component of the operating costs and is a risk coefficient for airlines. Several studies have been conducted on how oil price volatility affect stock prices and cash flows as well as how, in general, firms that uses derivatives experience lower stock returns volatility and stock s .The impact of oil price volatility on airline stock s and the impact of hedging on airline stock s have not been adequately examined, this paper fills this gap. By gathering daily frequency of oil spot prices to access the quarterly oil price volatility and stock s from 16 European airlines, we correlate quarterly oil price volatility to quarterly airline stock s as well as stock s and hedging percentages between 2010-2015, we reject the hypothesis that oil price volatility has an impact on airline stock s and that hedging reduces stock s. These findings therefore suggest that oil price volatility do not have a large impact on systematic risks or that hedging offset systematic risks. The findings are of interest to investors who want to make well informed investment decisions based on non-diversifiable equity risk since it has become popular for management recently to implement hedging policies to signal competency in risk management in order to attract investments.
18

Caracterização do mercado de combustível de aviação: um estudo de Organização Industrial / The aviation fuel market characterization: a study of Industrial Organization

Palauro, Gustavo Rodolfo 25 February 2015 (has links)
Esse trabalho faz da indústria de combustível de aviação no Brasil, especificamente o querosene de aviação - QAV, o seu objeto de pesquisa, uma vez que a mesma, do ponto de vista da estrutura de mercado, se caracteriza pela presença de poucas empresas atuantes desde a produção do bem até a sua distribuição, possibilitando o exercício de poder de mercado, levando à perda de bem estar social e alocação ineficiente de recursos. Ademais, busca analisar o ambiente institucional e como são formados os preços desse combustível no Brasil, tanto a nível de produtor quanto a nível do distribuidor, visto que os preços nacionais do querosene de aviação ao consumidor são elevados em relação aos preços praticados no mercado internacional. Devido a isso, esse estudo visa identificar também a existência de poder de mercado no segmento de distribuição desse combustível. O que tem se verificado no período de análise desta pesquisa é o Estado intervindo na política de preços de alguns combustíveis, por exemplo a gasolina, através da Petrobras, empresa aberta de capital misto sendo o governo nacional o maior acionista, e que é líder no mercado de refino e distribuição de derivados no país, apesar da desregulamentação nacional do setor do petróleo e seus derivados iniciada na década de 1990 e finalizada em 2001. A indústria nacional de querosene de aviação tem apresentado consideráveis índices de consumo e produção no período recente, devido principalmente ao aumento na demanda pelo transporte aéreo no país na última década. Por fim, a lacuna existente na literatura sobre a indústria referida motivou a realização da pesquisa, almejando contribuir para o entendimento da estrutura de mercado e formação de preços, bem como apresentar o ambiente institucional em que tal sistema produtivo está inserido. Para tanto, são utilizadas vertentes teóricas da Organização Industrial, especificamente o paradigma Estrutura-Conduta-Desempenho (ECD), a Nova Economia das Instituições (NEI) e a NEIO (New Empirical Industrial Organization). / This paper has the Brazilian aviation fuel industry (specifically the jet fuel) as object of research since that, from the point of structural view, is characterized by the presence of few firms operating in the production and in the distribution segment, which ones may exert market power, leading to loss of social welfare and inefficient allocation of resources in the economy. Moreover, aims to analyze the institutional environment of that industry and how the jet fuel prices are formed in national market, both at the producer and distributor level, since domestic prices of aviation fuel to consumers are high in comparison to that in the international market. Because of this aspect, the study also aims to identify the existence, or not, of market power in the Brazilian jet fuel distribution segment. Currently, what has been verified during the analysis period of this research is the Union intervening in pricing policy of some fuel, e.g. gasoline, through Petrobras, a mixed capital company, being the national government the largest shareholder, leader in the refining and distribution of oil products in the Brazilian market, despite the national deregulation oil and its derivatives, which started in the 1990s and was completed in 2001. Beyond these issues, the potential of the jet fuel industry is remarkable, showing considerable rates of consumption and production in the recent period, due to an increase in the national demand by air transportation in the last decade. Finally, the gap in the literature about the Brazil\'s industry of jet fuel is a notable fact to accomplish this study witch will contribute to the structural and institutional understanding of it. Therefore, to support this paper, theoretical stands of Industrial Organization are used, specifically the paradigm Structure-Conduct-Performance (SCP), the New Institutional Economics (NIE) and the New Empirical Industrial Organization (NEIO).
19

Desulfurization and Autothermal Reforming of Jet-A Fuel to Produce Syngas for Onboard Solid Oxide Fuel Cell Applications

Xu, Xinhai January 2014 (has links)
Fuel cell is one of the most promising clean energy and alternative energy technologies due to its advantages of low emissions and high efficiency. One application of the fuel cell technology is onboard auxiliary power units (APUs) for power generation in aircrafts, ships, and automobiles. In order to supply hydrogen or syngas for the fuel cell APUs, onboard fuel processing technology was proposed to convert hydrocarbon fuels into syngas through reforming reactions. Two major tasks need to be completed in onboard fuel processing technology. Firstly sulfur compounds have to be removed from hydrocarbon fuels because sulfur can cause reforming catalyst deactivation and fuel cell electrodes poisoning problems. Secondly hydrogen and carbon monoxide shall be produced by reforming of hydrocarbon fuels at a high energy conversion efficiency. This dissertation focused on onboard fuel processing of Jet-A fuel to produce hydrogen and syngas for solid oxide fuel cell (SOFC) APUs. Jet-A fuel was studied because it is the logistic fuel commonly used for civilian airplanes and military heavy duty trucks. Ultra-deep adsorptive desulfurization of Jet-A fuel from over 1,000 ppmw to below 50 ppmw, and autothermal reforming of n-dodecane as a Jet-A fuel surrogate as well as the real desulfurized Jet-A fuel to produce syngas have been systematically investigated in the present study. For the adsorptive desulfurization of Jet-A fuel, a novel NiO-CeO₂/A1₂O₃-SiO₂ adsorbent was proposed and prepared in-house for experimental tests. The sulfur adsorption kinetic characteristic and isotherm at equilibrium were studied in batch tests, and the dynamic desulfurization performance of the adsorbent was investigated in fixed bed tests. Fixed bed tests operation conditions including liquid hourly space velocity (LHSV), adsorbent particle size, and fixed bed dimensions were optimized to achieve the highest adsorbent sulfur adsorption capacity. For the reforming of Jet-A fuel, autothermal reforming (ATR) method was employed and a bimetallic NiO-Rh catalyst was synthesized for the ATR reactions. A lab-scale 2.5 kWt autothermal reforming system including the reformer and balance-of-plant was designed, fabricated, integrated and tested. The reforming system performances at various operation conditions were compared. Reformer operation temperature, steam to carbon ratio and oxygen to carbon ratio, as well as pre-heating temperatures for fuel, air and steam were optimized based on system energy conversion efficiency, H₂ selectivity and COₓ selectivity.
20

Ageing of HDPE Geomembranes Used to Contain Landfill Leachate or Hydrocarbon Spills

Rimal, SANTOSH 14 January 2009 (has links)
The ageing of high density polyethylene geomembrane (GM) liners used to minimize advection and diffusion of contaminants in municipal solid waste landfill leachate and in hydrocarbon spills to the environment is examined. The evaluation of the ageing of GMs used in landfills involved four components. First, a laboratory-accelerated ageing investigation of a GM exposed to air, water and leachate at elevated temperatures. Service life of a GM (Stage I: Antioxidant depletion, Stage II: Induction, and Stage III: Polymer degradation) is examined. The results demonstrate the critical role of antioxidants in protecting against oxidative degradation. The service life of the GM is predicted. Second, a study was conducted to provide an estimate of Stage I for a GM in a composite liner. The results indicated that immersion tests are too severe and the service life is substantially greater for a GM in composite liner than implied by leachate immersion tests. Third, a comparison of ageing with three different “protection” layers between the GM and overlying gravel and leachate is reported. A slower antioxidant depletion rate is observed when geotextile-geosynthetic clay liner and geotextile-sand-geotextile are applied than with a typical geotextile alone. This could be partially attributed to the attenuation of leachate constituents by the protection layer as well as the buildup of antioxidant concentration on either side of GM thereby reducing the concentration gradient and outward diffusive flux of antioxidants. Fourth, diffusion modelling is used to evaluate the results from immersion and composite liner simulation tests. Diffusion modelling provided a means for predicting the performance of the GMs in conditions other than the typical test conditions. The evaluation of the ageing of GM used in barrier system for hydrocarbon involved two components. First, untreated and fluorinated GMs immersed in jet fuel were tested. Results show that antioxidants depleted at slower rate from fluorinated GM than untreated GM. This suggested a significant beneficial effect of fluorination. Antioxidant depletion time is predicted at field temperatures. Second, the time dependant change in GM samples used at jet fuel containment site constructed in 2001 is reported. The GM is shown to be performing very well. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2009-01-14 10:46:31.089

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