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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.
231

Processamento do glicerol bruto em reatores anaeróbios de leito fluidificado, acidogênico e metanogênico, em temperatura mesofílica / Processing of crude glycerol in anaerobic fluidized bed reactors, acidogenic and methanogenic, at mesophilic temperature

Simões, Andreza Nataline 24 March 2017 (has links)
A utilização de combustíveis renováveis tem se destacado nos últimos anos, principalmente devido aos impactos ambientais gerados pelo uso de combustíveis fósseis e escassez dos mesmos. Dentre os combustíveis renováveis destaca-se o biodiesel, cujo processo produtivo apresenta como principal subproduto o glicerol bruto, que tem instigado nos últimos anos intensas discussões sobre a problemática de sua destinação e disposição final. Apesar de ser utilizado na indústria química, o seu teor de impurezas limita o seu processamento industrial. Buscando agregar valor a esse resíduo bruto e contribuir para a produção de bioenergia, este trabalho teve por intuito avaliar a produção dos biocombustíveis hidrogênio e metano, assim como de intermediários químicos a partir de glicerol bruto como substrato em reatores anaeróbios de leito fluidificado (RALF), mesofílicos (30°C), utilizando inóculo de cultura mista. O RALF-H2, com o objetivo de produzir hidrogênio e metabólitos solúveis, foi submetido à concentração de 10 g.L-1 de glicerol e variação do tempo de detenção hidráulica (TDH) de 8, 6, 4, 2, 1 e 0,5 h. Já o RALF-CH4, com intuito de produzir metano, operou sob TDH fixo de 24 h, submetido à variação da concentração de glicerol de 1, 2, 3, 4, 5 e 7 g.L-1, e portanto, da taxa de carregamento orgânico (TCO) de 1, 2, 3, 4, 5 e 7 kgDQO.m-3.d-1, respectivamente. No RALF-H2, os valores máximos de conteúdo de hidrogênio no biogás (69,2 %), produtividade volumétrica de hidrogênio (1,90 L.h-1.L-1) e rendimento de hidrogênio (0,28 molH2.mol-1glicerolconsumido) foram verificados no TDH de 0,5 h. O 1,3-propanodiol se destacou entre os metabólitos produzidos, com rendimento máximo de 0,57 mol1,3-PDO.mol-1glicerolconsumido, alcançado no TDH de 8 h. No RALF-CH4, o máximo conteúdo de metano no biogás (83,0%) foi verificado na TCO de 1 kgDQO.m-3.d-1, a maior produtividade volumétrica de metano (2,26 L.d-1.L-1) na TCO de 5 kgDQO.m-3.d-1 e o máximo rendimento (0,19 m3H4.kg-1DQOaplicada ou 0,77 molCH4.mol-1glicerolconsumido) na TCO de 4 kgDQO.m-3.d-1. Portanto, os resultados evidenciaram a possibilidade de produção de biocombustíveis e metabólitos de valor agregado utilizando glicerol bruto como substrato no processo da digestão anaeróbia. / The use of renewable fuels has been highlighted in recent years, mainly due to the environmental impacts generated by the use of fossil fuels and their scarcity. Among the renewable fuels highlights the biodiesel, whose production process displays as the main byproduct crude glycerol, which has instigated in recent years, intense debates about a problem of its destination and final disposal. Although it is used in the chemical industry, its impurities content limits its industrial processing. In order to add value to this crude residue and to contribute to the production of bioenergy, this work aimed to evaluate the production of biofuels hydrogen and methane, as well as chemical intermediates from crude glycerol as substrate in anaerobic fluidized bed reactors (AFBR), mesophilic (30°C), using mixed culture inoculum. The AFBR-H2, with the objective of producing hydrogen and soluble metabolites, was submitted to a concentration of 10 g.L-1 of glycerol and a variation of the hydraulic retention time (HRT) of 8, 6, 4, 2, 1 and 0.5 h. The AFBR-CH4, with the intention of producing methane, operated under fixed HRT of 24 h, subjected to the variation of the glycerol concentration of 1, 2, 3, 4, 5 and 7 g.L-1 and, therefore, of the organic loading rate (OLR) of 1, 2, 3, 4, 5 and 7 kgCOD.m-3d-1, respectively. In the AFBR-H2, the maximum values of hydrogen content in the biogas (69.2%), hydrogen volumetric productivity (1.90 L.h-1.L-1) and hydrogen yield (0.28 molH2.mol-1glycerolconsumed) were verified in the HRT of 0.5 h. The 1,3-propanediol was highlighted among the metabolites produced, with a maximum yield of 0.57 mol1,3-PDO.mol-1glycerolconsumed, reached in the TDH of 8 h. In the AFBR-CH4, the higher methane content in the biogas (83.0%) was detected in the OLR of 1 kgCOD.m-3.d-1, a higher volumetric productivity of methane (2.26 L.d-1.L-1) in the OLR of 5 kgCOD.m-3.d-1 and the maximum yield (0.19 m3CH4.kg-1CODapplied or 0.77 molCH4.mol-1glycerolconsumed) in the OLR of 4 kgCOD.m-3d-1. Therefore, the results evidenced the possibility of producing biofuels and value-added metabolites using crude glycerol as a substrate at the anaerobic digestion process.
232

Risks Related to the Maritime Transportation of Oil and Gas (mainly Crude oil, LPG, and LNG) -A Conceptual Study and Empirical Outlook on the Baltic Sea and UK Territorial Waters to Mitigate Risks

Razmjooee, Yarmohammad January 2012 (has links)
Transportation of oil and gas by the Sea characterizes challenges from a safety viewpoint. In this type of transportation, different sizes of special tankers carrying oil and gas. The marine transportation of these scarce natural riches is involved with risks and hazards, which may lead to many losses; for instance, wasting oil and gas, injuries of people, damaging ships and properties, and damaging environment. The main purpose of this thesis is to evaluate the risks, hazards, and accidents during transportation of oil and gas (mainly Crude Oil, liquefied petroleum gas, and Liquefied natural gas) by the Sea with concentrating on transport safety. Hence, a better understanding of these risks and hazards can contribute to decrease of addressed losses.This study is carried out on risks associated with maritime transportation of oil and gas starting with describing the general casual chain (dealing with causes, incidents, accidents and consequences/causalities), continuing with describing risk analysis techniques (including event tree analysis and fault tree analysis) and risk control measures/options, and finally implementing aforesaid investigations on real data from two areas; namely UK territorial waters and the Baltic Sea.In this study, the results of analyzing data from 1991 to 2010 in UK territorial waters revealed that collision and grounding were two most common accidents in terms of crude oil tankers, LPG and LNG carriers in which 44% of all accidents were equally divided between collision and grounding. In this case, investigation on data from 2004 to 2010 in the Baltic Sea regarding tankers with cargo types of crude oil, oil, oil product and gases also repeated the same findings in that collision and grounding shared the biggest proportion of accidents with 50% and 34% respectively. Analysis of data in UK territorial waters provided that human factor was the main reason behind accidents with 46% followed by technical factor with 39%. Human factor and technical factor recognized also as the main causes of accidents in the Baltic Sea with 33% and 25% respectively. Regarding this subject, human error recognized as the chief culprit and failures in part of design & construction was the second main initial causes of accidents in terms of both human and technical factors. The results of analyzing records from the Baltic Sea also provided that whilst human factor shared the biggest proportion of causes behind accidents, technical factor was the only cause of accidents contributing to all types of accidents. Findings are useful from safety outlook as if specifying accidents and causes of accidents during the Sea transportation of oil and gas. / Program: MSc in Industrial Engineering - Logistics Management
233

Etude de la précipitation d’asphaltènes dans des bruts petroliers induite par des gaz sous haute pression / Study of asphaltene precipitation in oils induced by gases at high pressures

Felipe Mauro, Rena Cardoso 18 December 2014 (has links)
Les activités de production des hydrocarbures sont fortement dépendantes du comportement thermodynamique des fluides produits. La précipitation d'asphaltènes, entités qui constituent les principaux composants de la fraction la plus lourde et la plus polaire du pétrole, peut conduire à la formation d'un dépôt solide. Nous avons mis en oeuvre et évalué plusieurs méthodologies expérimentales appliquées à la détermination des diagrammes de phase de fluides asphalténiques dans les conditions de haute pression et haute température. Nous avons mis au point une technique utilisant un résonateur à cristal de quartz (RCQ), capable d'identifier les conditions thermodynamiques de changement de phase, sous haute pression, dans des fluides avec une teneur faible en asphaltènes. Les données obtenues avec le RCQ ont été validées par filtration isobare et par microscopie haute pression (MHP). Les effets sur la floculation de l'ajout de gaz, des conditions thermodynamiques imposées au fluide et de la vitesse de dépressurisation ont été étudiés expérimentalement à l'aide des trois techniques susmentionnées. Les résultats obtenus par MHP sur différentes live oils suggèrent l'existence de quatre types de comportement de fluides lors d'une dépressurisation isotherme, avec dans certains cas l'apparition d'un équilibre liquide-liquide dans des conditions de températures et de pressions élevées. Enfin, nous avons établi, avec la caractérisation physico-chimique des asphaltènes obtenus (nC7) à partir des huiles mortes, que la différence d'aromaticité entre cette fraction et celle de son huile d'origine, pouvait être un indicateur utile afin d'anticiper un possible phénomène de précipitation. / Oil production activities are strongly dependent on the phase behavior of produced fluids. The flocculation of asphaltenes, the major components of the heaviest and most polar fraction of crude oil, can lead to solids formation in several steps of oil production. In this thesis, we evaluated several methodologies applied for asphaltenes phase behavior assessment under high-pressure conditions. Among the methodologies, we had developed an apparatus based on the quartz crystal resonator (QCR), able to identify thermodynamic conditions of phase changes in pressurized fluids containing low asphaltenes content. The data obtained with the QCR were validated by isobaric filtration and high pressure microscopy (HPM) tests. Applying the three aforementioned techniques, the influence of gas addition, kinetic factors, thermodynamic conditions and the influence of depressurization rate on the onset of asphaltenes flocculation were studied. Live oils were evaluated by the HPM technique. The results from HPM suggest the existence of four phase behavior patterns for isothermal depressurization experiments, highlighting the existence of a liquid-liquid equilibrium at elevated temperatures and pressures. The physico-chemical characterization of asphaltenes extracted with n-heptane from dead oil suggests that the difference of aromaticity between this fraction and its referred oils could be a parameter to indicate possible problems of asphaltenes flocculation during the oil production.
234

Desempenho agronômico e nutricional do capim "Mulato II" sob doses e fontes de nitrogênio / Agronomic and nutritional performance of "Mulato II" grass under doses and nitrogen sources

Jacovetti, Reginaldo 21 December 2016 (has links)
Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2017-01-27T09:26:39Z No. of bitstreams: 2 Tese - Reginaldo Jacovetti - 2016.pdf: 1575685 bytes, checksum: 7c74636241dd53c9dc6337a9b4fd0537 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-01-30T10:00:01Z (GMT) No. of bitstreams: 2 Tese - Reginaldo Jacovetti - 2016.pdf: 1575685 bytes, checksum: 7c74636241dd53c9dc6337a9b4fd0537 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-01-30T10:00:01Z (GMT). No. of bitstreams: 2 Tese - Reginaldo Jacovetti - 2016.pdf: 1575685 bytes, checksum: 7c74636241dd53c9dc6337a9b4fd0537 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-12-21 / Aiming a commercial competitiveness to the brazilian final product, in the current situation, the beef cattle industry shows itself as the largest herd in the world, but with low production by area. To Brazil improve zootechinical indexes, is necessary to product with knoledge, enviromental sustainability and first of all respecting the limits of all involved in the process like wather, soil, environment, plant, plant and man. Amomng this limits we need to respect all productive process of each regional structure and comerce for example large curlures, horticulture and livestock. If not respected this limits and regional structure is compromised the economical part of the system. To produce beef we need a lot o sources like wather "scarce resource" , agricultural area, and so cattle as feeded by grass, what kind of feed could be inserted in each region, and finaly we bring the knowledge that we need informations like local annual precipitation, maximun and minimum temperature, informations about phisical and chemical characteristics os the soil to be secure about your investiment. To animal production is required specific knowledge to produce without degradate the environment, making the zootechical indexes persist, respectiong the plant limit production, aminal limit production and environmental sustainability. There are many forrage cultivars to pasture, among them a recently released hybrid Brachiaria genotype "Convert HD 364" cv Mulato II, that requires research to identify the type of growth, production per area of dry matter and bromatological parameters to define the forrage production potencial. So was analysed the total area production, laboratory analyses to characterize the bromatological production, apparent nitrogen recover and total crude protein production of Mulato II. To qualitative analyse was made a in situ and in vitro gas production of Mulato II grass. / Visando a competitividade comercial para o produto final brasileiro, nas atuais conjunturas a pecuária de corte se mostra a frente com o maior rebanho comercial do planeta, com produções por área, a desejar. Para que produtivamente o Brasil melhore ainda mais seus índices zootécnicos faz se necessário produzir com conhecimento, sustentabilidade ambiental e principalmente respeitando os limites de todos os envolvidos no processo produtivo. Limites ambientais como água, solo, clima, planta, animal, homem. Produtivo, o que pode ser feito em determinada região, agricultura, hortifrutigranjeiro, pecuária, qual sistema pode ser incorporado em determinadas regiões do país. Sistema e o todo, tudo aquilo que faz parte do processo produtivo, não se produz economicamente não estando inserido em um sistema. Se produzimos boi necessita-se de terra, água "recurso escasso", área agricultável, afinal boi se alimenta de capim, que tipo de alimento pode ser inserido em determinada região, então chega-se ao conhecimento que necessita de informações do tipo, qual a precipitação anual de determinada localidade, qual a temperatura máxima e mínima no decorrer do ano, o solo é ácido, argiloso, arenoso, afinal quem vai fazer investimentos sem conhecimento de onde está empregando seu dinheiro. A produção animal necessita de conhecimentos específicos para que se possa produzir sem degradar o ambiente, fazendo com que o sistema perdure e seus índices zootécnicos sejam produtivo dentro dos limites de produção da planta, do animal, ambiente e do manejo do homem "conhecimento" Existem infinitas cultivares para pastagens, dentre elas o lançamento de um genótipo de Brachiaria híbrida "Convert HD364" cv Mulato II, que necessita de pesquisas para identificação de habito de crescimento, produção por área, quantitativamente quanto qualitativamente, para estimar qual será a produção do produto final por área empreendida dentro do sistema. Assim, foi analisado a produção por área, realizadas analises laboratoriais para caracterização da composição bromatológica, a recuperação aparente de nitrogênio, a eficiência de conversão de nitrogênio e a produção de proteína bruta por área do capim Mulato II. Para verificação qualitativa realizou-se a digestibilidade in sito e produção de gases in vitro do capim Mulato II.
235

Consumo e disgestibilidade de pastagem nativa do bioma pampa e inclusões de azevém

Rosa, Fabiane Quevedo da 26 August 2016 (has links)
Submitted by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2016-09-23T20:43:47Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) FABIANE QUEVEDO DA ROSA.pdf: 623070 bytes, checksum: d6e7ed987a04d5ad296d7f91b6123a7d (MD5) / Approved for entry into archive by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2016-09-23T20:44:00Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) FABIANE QUEVEDO DA ROSA.pdf: 623070 bytes, checksum: d6e7ed987a04d5ad296d7f91b6123a7d (MD5) / Made available in DSpace on 2016-09-23T20:44:00Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) FABIANE QUEVEDO DA ROSA.pdf: 623070 bytes, checksum: d6e7ed987a04d5ad296d7f91b6123a7d (MD5) Previous issue date: 2016-08-26 / Com o objetivo de avaliar a proteína bruta fecal como indicador de consumo e digestibilidade de bovinos alimentados com pastagem nativa situada no Bioma Pampa e inclusões de azevém e avaliar a qualidade nutricional dessas pastagens foram realizados dois experimentos em gaiolas de metabolismo. No experimento I, os animais recebiam diferentes níveis de oferta de pastagem nativa onde os tratamentos consistiam em níveis de1,5 e 2,25% do peso vivo de matéria seca e um nível ad libitum, com pelo menos 20% de sobras diárias onde foram realizados seis períodos experimentais, O experimento II consistia em diferentes níveis de inclusão de azevém na dieta de bovinos alimentados com campo nativo, os tratamentos eram 33%, 66% e 100% de azevém em substituição ao campo nativo, em dois períodos experimentias. Os experimentos foram realizados em delineamento inteiramente casualizado com 3 tratamentos e 2 repetições por tratamento em cada período. Os períodos experimentais consistiram de 10 dias de adaptação e 5 dias de coletas, durante o período de coletas foram amostradas as sobras do cocho, a forragem ofertada e ainda a produção total de fezes a cada 24 horas. Realizou-se as medidas de produção fecal, concentração de componentes fecais, consumo de nutrientes e digestibilidade dos componentes da dieta. No capítulo I foram traçadas relações entre digestibilidade e a concentração da proteína bruta fecal (PBf), sendo testados dois modelos não lineares, o exponencial e o hiperbólico gerando as equações de digestibilidade da matéria orgânica(DMO) = 0,709-9,506* exp(-0,041*PBf) com R2 0,61 e DMO = 0,942-38,619/PBf (R2 0,62), respectivamente. A relação de consumo de matéria orgânica (CMO) com a quantidade de PBf, possui comportamento linear, foi então realizada a análise de stepwise para saber quais outras variávies poderiam explicar melhor o modelo junto com a PBf gerando uma equação CMO = -6724,30 + 39*PBf + 2,55*FDNf + 11591,44*DMO com R2 0,95. Determinou-se a relação da proteína bruta (PB) da dieta (g/kg MO) x PBfecal (g/kg MO), PB dieta = 1,346x - 47,63 R² = 0,931 (modelo linear). No capítulo II, foram testados dois modelos para todas as relações traçadas no experimento II, um modelo linear e um modelo quadrático, as relações foram consumo de matéria orgânica (CMO (g/UTM)) x digestibilidade da fibra em detergente neutro (DFDN), DMO x CMO (g/UTM), DMO x CMO (g/dia), consumo de folhas (g/UTM) x DMO e CMO (g/UTM) x relação proteína/energia. As relações que não foram estatisticamente significativas para nenhum modelo foram CMO (g/UTM) x relação proteína/energia e consumo de folhas (g/UTM) x DMO. Após essas relações, verificou-se que a PBf tem um bom potencial para a estimativa de consumo e a digestibilidade por bovinos alimentados com pastagens nativas ou associadas a forragem cultivada como o azevém anual, mas estes parâmetros também são afetados por diferentes variáveis. / In order to evaluate the fecal crude protein as intake and digestibility marker of cattle fed with natural pasture from Pampa Biome and annual ryegrass inclusions and evaluate the nutritional quality of these pastures it was conducted two experiments in metabolic cages. In the first experiment, the animals received different native pasture offer levels where treatments consisted of 1.5 and 2.25% of the live weight of dry matter and ad libitum with at least 20% of daily leftovers which were carried out six experimental periods. The second experiment consisted of annual ryegrass inclusion levels in the diet of cattle fed with natural pasture, the treatments were 33%, 66% and 100% of ryegrass to replace the native pasture in two experimental periods. The experiments were carried out in a completely randomized design with 3 treatments and 2 replicates per treatment in each period. The experimental period consisted of 10 days of adaptation and 5 days of collection during the period of the trough collects the forage offered have been sampled, the leftovers and also the total fecal production in each 24 hours. It was measured the fecal productions, concentration of faecal components, nutrient intake and digestibility of diet components. In the Chapter I were study the relationship between digestibility and fecal concentration of crude protein (CPf), being tested exponential and hyperbolic equations generating the digestibility of organic matter (OMD) = 0.709 - 9.506 * exp (- 0.041 * CPf) with R2 = 0.61 and OMD =0.942 - 38.619 / CPf (R2 0.62), respectively. The ratio of organic matter intake (OMI) with the amount of CPf, has a linear relation, it was then carried out stepwise analysis to find out what other variables could explain better the model along with the CPf generating a equation OMI = -6724.30 + 0,998 * CPf + 2.55 * NDFf + 11591.44 * OMD with R2= 0.95. It was determined the ratio of crude protein (CP) of the diet (g/kg of OM) x CPf (g/kg of OM), CPdiet = 1,346*CPf - 47.63 R² = 0.931 (linear model). In the Chapter II were tested two models for all relationships outlined in experiment II, a linear model and a quadratic model, relations were organic matter intake (OMI) x digestibility of neutral detergent fiber (DNDF), OMD x OMI, leaves intake x OMD and OMI x protein/energy ratio. The relationships that were not statistically significant for either model were OMI x protein/energy and leaves intake x OMD. After these relationships, it was found that the CPf has a good potential to estimate intake and digestibility in cattle fed native pastures or associated with annual ryegrass, but these parameters are also affected by different variables.
236

Hyperspectral Remote Sensing of Temperate Pasture Quality

Thulin, Susanne Maria, smthulin@telia.com January 2009 (has links)
This thesis describes the research undertaken for the degree of Doctor of Philosophy, testing the hypothesis that spectrometer data can be used to establish usable relationships for prediction of pasture quality attributes. The research data consisted of reflectance measurements of various temperate pasture types recorded at four different times (years 2000 to 2002), recorded by three hyperspectral sensors, the in situ ASD, the airborne HyMap and the satellite-borne Hyperion. Corresponding ground-based pasture samples were analysed for content of chlorophyll, water, crude protein, digestibility, lignin and cellulose at three study sites in rural Victoria, Australia. This context was used to evaluate effects of sensor differences, data processing and enhancement, analytical methods and sample variability on the predictive capacity of derived prediction models. Although hyperspectral data analysis is being applied in many areas very few studies on temperate pastures have been conducted and hardly any encompass the variability and heterogeneity of these southern Australian examples. The research into the relationship between the spectrometer data and pasture quality attribute assays was designed using knowledge gained from assessment of other hyperspectral remote sensing and near-infrared spectroscopy research, including bio-chemical and physical properties of pastures, as well as practical issues of the grazing industries and carbon cycling/modelling. Processing and enhancement of the spectral data followed methods used by other hyperspectral researchers with modifications deemed essential to produce better relationships with pasture assay data. As many different methods are in use for the analysis of hyperspectral data several alternative approaches were investigated and evaluated to determine reliability, robustness and suitability for retrieval of temperate pasture quality attributes. The analyses employed included stepwise multiple linear regression (SMLR) and partial least squares regression (PLSR). The research showed that the spectral research data had a higher potential to be used for prediction of crude protein and digestibility than for the plant fibres lignin and cellulose. Spectral transformation such as continuum removal and derivatives enhanced the results. By using a modified approach based on sample subsets identified by a matrix of subjective bio-physical and ancillary data parameters, the performance of the models were enhanced. Prediction models from PLSR developed on ASD in situ spectral data, HyMap airborne imagery and Hyperion and corresponding pasture assays showed potential for predicting the two important pasture quality attributes crude protein and digestibility in hyperspectral imagery at a few quantised levels corresponding to levels currently used in commercial feed testing. It was concluded that imaging spectrometry has potential to offer synoptic, simultaneous and spatially continuous information valuable to feed based enterprises in temperate Victoria. The thesis provide a significant contribution to the field of hyperspectral remote sensing and good guidance for future hyperspectral researchers embarking on similar tasks. As the research is based on temperate pastures in Victoria, Australia, which are dominated by northern hemisphere species, the findings should be applicable to analysis of temperate pastures elsewhere, for example in Western Australia, New Zealand, South Africa, North America, Europe and northern Asia (China).
237

Financial forecasting using artificial neural networks

Prasad, Jayan Ganesh, Information Technology & Electrical Engineering, Australian Defence Force Academy, UNSW January 2008 (has links)
Despite the extent of a theoretical framework in financial market studies, a vast majority of the traders, investors and computer scientists have relied only on technical and timeseries data for predicting future prices. So far, the forecasting models have rarely incorporated macro-economic and market fundamentals successfully, especially with short-term predictions ranging less than a month. In this investigation on the predictability of certain financial markets, an attempt has been made to incorporate a un-exampled and encompassing set of parameters into an Artificial Neural Network prediction system. Experiments were carried out on three market instruments ??? namely currency exchange rates, share prices and oil prices. The choice of parameters for inclusion or exclusion, and the time frame adopted for the experimental sets were derived from the market literature. Good directional prediction accuracies were achieved for currency exchange rates and share prices with certain parameters as inputs, which consisted of predicting short-term movements based on past movements. These predictions were better than the results produced by a traditional least square prediction method. The trading strategy developed based on the predictions also achieved a higher percentage of winning trades. No significant predictions were observed for oil prices. These results open up questions in the microstructure of the markets and provide an insight into the inputs required for market forecasting in the corresponding time frame, for future investigation. The study concludes by advocating the use of trend based input parameters and suggests ways to improve neural network forecasting models.
238

An Experimental Study On Steam Distillation Of Heavy Oils During Thermal Recovery

Tavakkoli Osgouei, Yashar 01 March 2013 (has links) (PDF)
Thermal recovery methods are frequently used to enhance the production of heavy crude oils. Steam-based processes are the most economically popular and effective methods for heavy oil recovery for several decades. In general, there are various mechanisms over steam injection to enhance and have additional oil recovery. However, among these mechanisms, steam distillation plays pivotal role in the recovery of crude oil during thermal recovery process. In this study, an experimental investigation was carried out to investigate the role of various minerals present in both sandstone and carbonate formations as well as the effect of steam temperature on steam distillation process. Two different types of dead-heavy crude oils were tested in a batch autoclave reactor with 30 % water and the content of the reactor (crude oil, 10 % rock and mineral). The results were compared as the changes in the density, viscosity and chemical composition (SARA and TPH analyses) of heavy crude oil. Five different mineral types (bentonite, sepiolite, kaolinite, illite and zeolite) were added into the original crude oil and reservoir rocks to observe their effects on the rheological and compositional changes during steam distillation process. Analysis of the results of experiments with Camurlu and Bati Raman heavy crude oils in the presence of different minerals such as Bentonite, Zeolite, Illite, Sepiolite, and Kaolinite in both sandstone and limestone reservoir rocks indicate that steam distillation produces light end condensates which can be considered as solvent or condensate bank during steam flooding operation. It was also illustrated that minerals in reservoir formations perform the function of producing distilled light oil compounds, resulting in enhancement of heavy crude oils recovery in steam flooding. Measurements showed that the remaining oil after steam distillation has higher viscosity and density. On the other hand, the effect of steam distillation is more pronounced in limestone reservoirs compared to sandstone reservoirs for the given heavy crude oil and steam temperature. Among the five different minerals tested, kaolinite found to be the most effective mineral in terms of steam distillation.
239

Essays in Risk Management for Crude Oil Markets

Al Mansour, Abdullah 20 September 2012 (has links)
This thesis consists of three essays on risk management in crude oil markets. In the first essay, the valuation of an oil sands project is studied using real options approach. Oil sands production consumes substantial amount of natural gas during extracting and upgrading. Natural gas prices are known to be stochastic and highly volatile which introduces a risk factor that needs to be taken into account. The essay studies the impact of this risk factor on the value of an oil sands project and its optimal operation. The essay takes into account the co-movement between crude oil and natural gas markets and, accordingly, proposes two models: one incorporates a long-run link between the two markets while the other has no such link. The valuation problem is solved using the Least Square Monte Carlo (LSMC) method proposed by Longsta ff and Schwartz (2001) for valuing American options. The valuation results show that incorporating a long-run relationship between the two markets is a very crucial decision in the value of the project and in its optimal operation. The essay shows that ignoring this long-run relationship makes the optimal policy sensitive to the dynamics of natural gas prices. On the other hand, incorporating this long-run relationship makes the dynamics of natural gas price process have a very low impact on valuation and the optimal operating policy. In the second essay, the relationship between the slope of the futures term structure, or the forward curve, and volatility in the crude oil market is investigated using a measure of the slope based on principal component analysis (PCA). The essay begins by reviewing the main theories of the relation between spot and futures prices and considering the implication of each theory on the relation between the slope of the forward curve and volatility. The diagonal VECH model of Bollerslev et al. (1988) was used to analyse the relationship between of the forward curve slope and the variances of the spot and futures prices and the covariance between them. The results show that there is a significant quadratic relationship and that exploiting this relation improves the hedging performance using futures contracts. The third essay attempts to model the spot price process of crude oil using the notion of convenience yield in a regime switching framework. Unlike the existing studies, which assume the convenience yield to have either a constant value or to have a stochastic behaviour with mean reversion to one equilibrium level, the model of this essay extends the Brennan and Schwartz (1985) model to allows for regime switching in the convenience yield along with the other parameters. In the essay, a closed form solution for the futures price is derived. The parameters are estimated using an extension to the Kalman filter proposed by Kim (1994). The regime switching one-factor model of this study does a reasonable job and the transitional probabilities play an important role in shaping the futures term structure implied by the model.
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Forecasting The Prices Of Non-ferrous Metals With Garch Models &amp / Volatility Spillover From World Oil Market To Non-ferrous Metal Markets

Bulut, Burcak 01 August 2010 (has links) (PDF)
In the first part of this thesis the prices of six non-ferrous metals (aluminum, copper, lead, nickel, tin, and zinc) are used to assess the forecasting performance of GARCH models. We find that the forecasting performances of GARCH, EGARCH, and TGARCH models are similar. However, we suggest the use of the GARCH model because it is more parsimonious and has a slightly better statistical performance than the other two. In the second part, the prices of six non-ferrous metals and the price of crude oil are used to examine the dynamic links between oil and metal returns by using the BEKK specification of the multivariate GARCH model and the Granger causality-in-variance tests. Results of our study agree with the previous studies in that the crude oil market volatility leads all non-ferrous metal markets. In order to move as far away from the effects of 9/11, daily data for the period December 12, 2003 &ndash / December 15, 2008 is used for the data analysis part of the thesis.

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