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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.
31

The effects of crude oil on terrestrial vegetation

Brown, Si January 1974 (has links)
Note:
32

Perspektívy vývoja na trhu s ropou / Perpectives of crude oil market developement

Vosková, Michala January 2008 (has links)
Crude oil is an important commodity of world trade and it has become an essential part of everyday life. It is a necessary condition of economic growth, which in the current situation of economic boom of China, India and other developing countries entails an economically, ecologically, socially and geopolitically unsustainable problem. The turbulent sequence of past events on the crude oil market only foreshadows the future development that is going to occure after achieving the crude oil production peak. The following irreversible changes will be more revolutionary than evolutional. The era of cheap oil will parish and the 21st century is going to be distinguished by fights for energy and resources. This is one of the reasons why many renowned institutions and organisations are concerned with these questions, trying to predict future scenarios and find feasible solutions. The world needs secure, renewable and environmentally friendly energy sources, however crude oil is unfortunately none of them. Radical transition from crude oil economy to a clean alternative one, that is probably the most suitable solution to current situation, will require engagement of governments, organisations and individuals as well. It is an inevitable step of preserving the world for humanity and the coming generations. Crude oil market perspectives are quite well foreseeable for the coming decades, questionable remains only the proper solution of the rising problems and action of taking the correct steps in the right direction.
33

Odhad cenové elasticity poptávky po ropě / Estimation of price elasticity of crude oil demand

Jonák, Ondřej January 2009 (has links)
Objective of this diploma thesis is estimation of price elasticity of crude oil demand. In order to calculation of such elasticity crude oil demand is estimated with econometrical methods. The choice of suitable model, which sufficiently and accurately models crude oil demand, is initial position of analysis. Consequently, crude oil demand is estimated from market data obtainable from public sources. This estimated model is verified from economic, statistic and econometric point of view. Consequently, price elasticity of crude oil demand is calculated from such model.
34

Optical techniques for crude oil and asphaltene characterization

Matoug, Mohamed 29 January 2018 (has links)
In this work, different optical techniques have been explored to study and characterize crude oil and its asphaltene. Crude oil is extremely complex fluid used to produce fuel for a wide range of applications. The characterization of this fluid is key for optimum operations in the oil and gas industry. First, we demonstrate the application of gold nanorods in characterizing a different set of crude oils. We utilize the high sensitivity of the Localized Surface Plasmon Resonance (LSPR) of the nanorods to the surrounding environment to measure the crude oil refractive index. We immobilized the nanorods on a glass substrate and took the measurement in a reflection configuration. The setup and the nanorods were calibrated using different fluids with known refractive index, and a sensitivity of 247 nm/RIU and a resolution of 0.013 RIU have been achieved. In addition to the simplicity of this approach, it has eliminated the absorption issue and made it possible to measure high optical density crude oils with typical Visible-NIR wavelengths. Surface-Enhanced Raman Spectra (SERS) can also be measured. SERS can provide additional useful information, especially to some applications such as downhole fluid analysis, where confirmation of the hydrocarbons presence is necessary. In the second part of this work, we used Terahertz Time-Domain Spectroscopy (THz-TDS) to study the asphaltene in three different crude oils. THz-TDS has a feature of measuring the amplitude and time delay and consequently the refractive index and absorption coefficient spectra simultaneously. Our approach is based on measuring the THz signal from neat crude oil samples and comparing it with the THz signal after removing the asphaltene from the samples (maltene). The results show that the difference in the time delay and the peak amplitude between the neat oil and the maltene have a linear relation with the asphaltene content. The refractive index spectra of different asphaltenes show variation in the low THz frequencies and comparable spectra in the higher frequencies. The absorption of asphaltene was mild and no distinctive absorption feature was observed except for some narrow absorption peaks that we attributed to water molecules adsorbed on the asphaltene. / Graduate
35

Přeprava ropy pro potřeby ČR / Transport of crude oil for the czech needs

Hořejší, Simona January 2008 (has links)
This thesis is focused on crude oil pipeline transport for the Czech Republic. It is concentrated on the company MERO ČR, a.s., which owns and operates czech part of the Družba crude oil pipeline and whole IKL crude oil pipeline. Futher it is concentrated on operation of both pipilines and the Central Crude Oil Tank Farm in Nelahozeves. At the end of my thesis there are concidered some alternative ways of crude oil transport for czech needs.
36

Simulation and analysis of gas freeing of oil tanks

Chow, K. January 2010 (has links)
This thesis presents an in-depth study of the gas freeing of marine crude oil tanks using numerical simulation, beginning with a general summary of the problem, followed by an outline of the objectives of this work and the main difficulties involved. To outline essential background, a review of numerical methods, fluid flow, and related physical mechanisms has been undertaken, in addition to related ventilation fields, jet and jet impingement, and tanker-borne ventilation, in order to determine the state of the art and draw useful parallels between different ventilative fields, as well as identifying potential areas for model validation. A room-ventilation test case was studied in order to demonstrate the numerical method. It was found that assuming adiabatic walls and ignoring radiation resulted in highly idealised temperature predictions, and that radiation played a large part in enhancing vertical temperature prediction by redistributing thermal energy. For the gas-freeing analysis, the geometric models and solution procedures are introduced before simulation results presented and validated with analytical jet models and impingement penetration parameters. Analysis showed that the internal temperature of the tank was approximately homogeneous, allowing the tank to be considered isothermal. 2D simulations showed that after an initial period of time, the relative concentration distribution reaches steady state with decreasing average concentration as gas-freeing continues. Discussion of the results followed, examining aspects surrounding heat transfer and the choice of turbulence model, analysing the differences in the results between the first and secondmoment closure schemes and justification of assuming isothermal conditions. The variation in concentration was examined, and an analytical expression was derived which approximates the reduction in average gas concentration decay due to gas-freeing. It has been shown that double-hulled construction renders the internal temperature variation to around 10% of the temperature difference between the sea and deck. During the gasfreeing process proper, it was shown that after any stratified layer has been eroded and a stable flow field established, the relative concentration distribution remains constant. Gas freeing times were shown to be heavily dependent on the volume flux (and thus air change rate), and mathematical relations derived in order to provide approximately predict the time to gas free a crude oil tank (COT) given particular initial conditions.
37

F2:F3b Ratio and BOC-Adjusted PHC F3 Approach to Resolving False Detections of Crude Oil and Diesel Drilling Waste in Clean Soils and Manure Compost

Kelly-Hooper, Francine Teresa 17 July 2013 (has links)
The Canadian Council of Ministers of the Environment (CCME) endorsed the Reference Method for the Canada-Wide Standard (CWS) for Petroleum Hydrocarbons (PHC) in Soil – Tier 1 Method in 2001. The purpose of the CWS is to provide laboratories with analytical methods for producing accurate and reproducible PHC soil chemistry analysis results. CWS PHC concentrations are reported according to the following carbon ranges/fractions: F1 (C6-C10), F2 (C10-C16), F3 (C16-C34) and F4 (>C34). The Canada-wide Standards for Petroleum Hydrocarbons (PHC) in Soil provide generic soil quality guidelines for the each of the four PHC fractions. The CWS PHC extraction solvents inadvertently co-extract natural biogenic organic compounds (BOC) from organic soils. BOCs, such as waxes and fatty acids, are produced by living organisms such as plants, animals and microbes. PHC analysis of highly organic clean soils and manure compost can cause false exceedences of the F3 soil quality guidelines. This thesis presents a new mathematical Tier 2 approach to resolving biogenic interferences through the use of biogenic versus petrogenic Gas Chromatography - Flame Ionization Detector (GC-FID) chromatogram patterns produced by the CWS PHC Tier 1 method. This approach is based on the results of four studies: i) 300-day crude oil contaminated peat and sand microcosm experiment; ii) 300-day diesel drilling waste contaminated manure compost and sand microcosm experiment; iii) PHC analysis of 14 light to heavy crude oils and iv) Canadian background PHC soil field survey. These studies determined that the clean soils and compost had F3 ranges that were dominated by the F3b sub-fraction range (C22-C34). In contrast, the F3a (C16-C22) and F3b sub-fraction ranges were evenly distributed in the 14 fresh light to heavy crude oils. The diesel drilling waste was strongly dominated by the F3a sub-fraction range. The second important trend was that F2 concentrations were either non-detectable or slightly detectable in all of the clean soils and compost samples. In contrast, F2 concentrations were strongly prevalent in all of the crude oils and in the diesel drilling waste. F2 and F3b concentrations were applied to the F2:F3b ratio, which identified PHC absence in the clean materials (<0.10 ratio) and PHC presence (>0.10 ratio) in the contaminated materials. The %F3a:%F3b distributions were applied to the BOC-adjusted PHC F3 calculation, which estimated true PHC F3 concentrations in the clean and contaminated soils and manure compost. The combination of these two approaches provided an accurate and efficient solution to resolving false detections of crude oil and diesel PHCs and false exceedences of F3 soil toxicity guidelines by in clean soils and compost.
38

Metabolic Responses to Crude Oil during Very Early Development in the Zebrafish (Danio rerio)

Vazquez Roman, Karem Nathalie 08 1900 (has links)
The present study sought to determine some morphological and physiological critical windows during very early development in zebrafish exposed to crude oil. I hypothesized that exposed zebrafish would present a decrease in survival rate and body mass, and an increase in routine oxygen consumption (ṀO2), and critical oxygen tension (PCrit). To test these hypotheses, zebrafish were acutely exposed (24 h) during different days of development (1 to 6 days post-fertilization, dpf) to different concentrations of high-energy water-accommodated fractions (HEWAFs). The endpoints of survival, body mass, routine oxygen consumption, and critical oxygen partial pressure were measured at 7 dpf. Survival rate decreased based on the exposure concentration but not as a function of the day of crude oil exposure. No significant effects were found in PCrit. Body mass was reduced by the different concentrations of HEWAF, with the size of the effect varying with exposure day, with the effect strongest on when exposure occurred at 2 and 3 dpf. Oxygen consumption (ṀO2) differed significantly depending upon the day of exposure in fish exposed to crude oil. Specifically, HEWAF exposure significantly increased ṀO2 in larvae exposed at 3 dpf (9.081 µmol O2/g/h, ±0.559) versus 2 dpf (6.068 µmol O2/g/h, ±0.652) and 6 dpf (6.485 µmol O2/g/h, ±0.609). Overall, the main effects on body mass and ṀO2 occurred at crude oil exposures during 3 dpf. The presence of a critical window in fish is proposed at this developmental time, which coincides with the hatching period.
39

A Study on Burning of Crude Oil in Ice Cavities

Farmahini Farahani, Hamed 29 April 2014 (has links)
In situ burning (ISB) is a practical method of oil spill cleanup in icy conditions. This study investigates one example of a likely oil spill scenario; burning oil in an ice cavity. In this situation, unique and unexplored physical processes come into play compared with the classical problem of confined pool fires in vessels. The icy walls of the cavity create a significant heat sink causing notable lateral heat losses especially for small cavity sizes (5-10 cm). Melting of ice because of the heat from the flame causes the geometry of cavity to change. Specifically, the diameter of the pool fire increases as the burning advances. This widening causes the fuel to stretch laterally thereby reducing its thickness at a faster rate. The melted ice water causes the oil layer to rise which causes the ullage height to decrease. The decrease in ullage and increase in diameter counteract the reduction in thickness because of widening or stretching of the fuel layer. There thus exists a strong coupling between the burning rate and the geometry change of the pool and cavity. To explore the problem, experiments were performed in circular ice cavities of varying diameters (5 - 25 cm). The change in shape of the ice cavity and the oil layer thickness are recorded using a combination of visual images, mass loss, and temperature data along the centerline and edge of the cavity. The average burning rate of crude oil in a cavity is greater than the corresponding burning rate in a vessel of equal diameter, yet the burning efficiency (% of fuel consumed during combustion) is lower. For example, the average mass loss rate in a 10 cm ice cavity is 50% higher than a steel vessel of similar size. However, the burning efficiency is lower by 50%. Widening of cavity (170%) contributes to the increase in the average mass burning rate. At the same time heat losses through fuel layer increase because of decrease in fuel thickness by widening of the fuel layer. This coupling is analyzed using a mathematical model which can predict burning rate and efficiency of crude oil in an ice cavity for the range of cavity diameters examined. Extension of the model to larger sizes comparable to realistic situations in the Arctic is discussed.
40

Biodiesel Production from Mixed Culture Algae Via a Wet Lipid Extraction Procedure

Sathish, Ashik 01 December 2012 (has links)
With world crude oil reserves decreasing and energy prices continually increasing, interest in developing renewable alternatives to petroleum-based liquid fuels has increased. An alternative that has received consideration is the growth and harvest of microalgae for the production of biodiesel via extraction of the microalgal oil or lipids. However, costs related to the growth, harvesting and dewatering, and processing of algal biomass have limited commercial scale production of algal biodiesel. Coupling wastewater remediation to microalgal growth can lower costs associated with large scale growth of microalgae. Microalgae are capable of assimilating inorganic nitrogen and phosphorous from wastewater into the biomass. By harvesting the microalgal biomass these nutrients can be removed, thus remediating the wastewater. Standard methods of oil extraction require drying the harvested biomass, adding significant energetic cost to processing the algal biomass. Extracting algal lipids from wet microalgal biomass using traditional methods leads to drastic reductions in extraction efficiency, driving up processing costs. A wet lipid extraction procedure was developed that was capable of extracting 79% of the transesterifiable lipids from wet algal biomass (16% solids) without the use of organic solvents while using relatively mild conditions (90 °C and ambient pressures). Ultimately 77% of the extracted lipids were collected for biodiesel production. Furthermore, the procedure was capable of precipitating chlorophyll, allowing for the collection of algal lipids independently of chlorophyll. The capability of this procedure to extract lipids from wet algal biomass, to reduce chlorophyll contamination of the algal oil, and to generate feedstock material for the production of additional bio-products provides the basis for reducing scale-up costs associated with the production of algal biofuels and bioproducts.

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