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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.
1

A Generalized Elastohydrodynamic Lubrication Model for Two-Dimensional Contacts

Chimanpure, Amit S. January 2020 (has links)
No description available.
2

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.
3

Investigation Of Productivity Of Heavy Oil Carbonate Reservoirs And Oil Shales Using Electrical Heating Methods

Hascakir, Berna 01 September 2008 (has links) (PDF)
The recovery characteristics of Bolu-Himmetoglu, Bolu-Hatildag, K&uuml / tahya- Seyit&ouml / mer, and Nigde-Ulukisla oil shale samples and Bati Raman, &Ccedil / amurlu, and Garzan crude oil samples were tested experimentally using retort and microwave heating techniques. Many parameters like heating time, porosity, water saturation were studied. To enhance the efficiency of the processes three different iron powders (i.e. / Fe, Fe2O3, and FeCl3) were added to the samples and the doses of the iron powders were optimized. While crude oil viscosities were measured to explain the fluid rheologies, since it is impossible to measure the shale oil viscosity at the laboratory conditions due to its very high viscosity, shale oil viscosities were obtained numerically by using the electrical heating option of a reservoir simulator (CMG, STARS 2007) by matching between the laboratory and numerical oil production and temperature distribution results. Then the field scale simulations for retorting of oil shale and crude oil fields were conducted. Since the microwave heating cannot be simulated by CMG, STARS, microwave heating was modeled analytically. In order to explain the feasibility of heating processes, an economic evaluation was carried out. The experimental, numerical, and analytical results show that field scale oil recovery from oil shales and heavy crude oils by electrical and electromagnetic heating could be economically viable. While microwave heating is advantageous from an operational point of view, retorting is advantageous if the technically feasibility of the study is considered.
4

Vliv vybraných aktivních látek na vlastnosti gelových a emulzních kosmetických základů / Influence of selected active compounds for properties of gel and emulsion cosmetics

Gardoňová, Lenka January 2009 (has links)
This master‘s thesis studies problems of chosen active substances in cosmetic emulsions and gels. There is their main characteristics – distribution and properties of cosmetic emulsions and gels, preparation of the active substances, effects on the skin and conditions, which could them influence. In experimental part, preparation of gels and emulsions bases was described which were than enriched by active substances - evening primrose oil, hemp oil, Salvia officinalis extract, Symphytum officinale extract and sea salt. Properties of these cosmetic gels and emulsions bases with the addition of active substances depend on temperature and method of storage, amount of light exposure, method of preparation and another conditions. Action of these factors can cause changes of the stability, thereby the cosmetics effects on the skin can be lost. On the bases of performed rheology measurements (oscillation and flow measurements), pH measurements and sensory analysis were determined, if the properties of examined samples were changed. The measurement was performed in the certain time intervals and the properties were evaluated like at laboratory temperature 23±2 °C, so after exposure to temperature regime 37 °C in thermoregulator. On the basis of performed measurements, there was determined, that gel base with addition of Symphytum officinale extract had the most stability properties.

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