Thèses sur le sujet « Various pressure and temperature conditions »
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Song, Chenlu. « Long-term observation of rock fracture permeability and structure under various pressure and temperature conditions ». Doctoral thesis, Kyoto University, 2020. http://hdl.handle.net/2433/253256.
Texte intégral0048
新制・課程博士
博士(工学)
甲第22420号
工博第4681号
新制||工||1731(附属図書館)
京都大学大学院工学研究科都市社会工学専攻
(主査)教授 岸田 潔, 教授 三村 衛, 准教授 肥後 陽介
学位規則第4条第1項該当
Doctor of Philosophy (Engineering)
Kyoto University
DFAM
Szilágyi, Robert. « Study of partial discharge and gas breakdown phenomena at a triple junction under various pressure and temperature conditions ». Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPAST007.
Texte intégralTriple junctions (between a gas, a solid insulator, and a conductor), which are present in numerous industrial applications, constitute a critical zone for the triggering of electrical discharges due to local reinforcement of the electric field. In addition, these triple points can be exposed to harsh environmental conditions. The aim of this study was therefore to come to a better understanding of the phenomena of partial discharge (PD) and gas breakdown from a triple junction under different pressure and temperature conditions. In particular, the Partial Discharge Inception Voltage (PDIV), the Partial Discharge Extinction Voltage (PDEV), and the Flashover Voltage (FOV) of surface breakdown of the solid insulator were examined.In this context, an experimental set-up was designed and operated in a nitrogen atmosphere ranging from 50 mbar to atmospheric pressure, for imposed temperatures varying from ambient to 400 °C. Particular attention was paid to aluminium oxide, a solid insulator material that can be used in this temperature range. The influence of temperature on PDIV (and PDEV) on the one hand, and FOV on the other, was characterised, analysed and interpreted by means of dielectric measurements, high-speed imagery and numerical simulations. Finally, under high temperature conditions and despite the precautions taken, an oxidation of the high voltage electrode was observed whose influence on the PDIV was analysed
Larsen, Håvard. « Behaviour of polymer muds under high pressure – high temperature conditions ». Thesis, Norwegian University of Science and Technology, Department of Petroleum Engineering and Applied Geophysics, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1534.
Texte intégralA well is classified as a HPHT (High Pressure High Temperature) well if the static bottomhole temperatures are greater than 350 °C and when the formation pressures exceed 1800 kg/m3 ECD. Mud weights as high as 2400 kg/m3 may be required to maintain a proper well control. The temperature of the drilling fluid when circulating in the well may range from 0 °C to 150 °C and it is important that the drilling fluid maintain acceptable rheological properties within the whole range. The rheological properties of the mud will strongly depend on the temperature and the pressure variations. The problems regarding HPHT wells are mostly due to ECD and cuttings transport.
In order to control and measure the viscosity for deep HPHT wells we have conducted laboratory experiments that deal with aging at different temperatures on a polymer mud, as well as pressure and temperature effects on a field mud. We have also calculated the annular pressure using Landmark Wellplan software. To calibrate the instruments, i.e. the Physica HPHT viscometer and a Fann viscometer, we used ubelohde, known to give an exact value of the viscosity of a fluid. The calibration liquid was a 2-stroke motor oil with different amounts of Exxsol-D60 added.
The aging experiments were conducted in a mixture of water and HEC that were put in three different incubators at 20 °C, 60 °C and 90 °C for 1, 3, 8, 11, 15 and 20 days. The results showed that the viscosity decreased rapidly in the solutions that were aged at the highest temperatures and that most of the decrease took place during the first day of aging.
In the experiments on real (field) mud exposed to high pressures and temperatures the Physica viscometer was used. The results showed that the pressure effects were negligible compared to the temperature effects. During the measurements we experienced that the viscosity decreased as the temperature increased and that the decrease in the viscosity was more significant from 20 to 60 °C than from 60 to 90 °C.
Based on the results obtained in the laboratory and an evaluation of fluid implication on well pressure, we were able to draw the following main conclusions:
• Laboratory experiments are very educational. To learn that reality is not straight forward to measure was enlightening.
• The viscosity is very dependant on the temperature.
• The combined effect of pressure on the viscosity of a field mud is negligible.
• The annular pressure differences calculated in Landmark Wellplan did not show any significant differences for the different well temperatures.
Bagdanavicius, Audrius. « Premixed combustion of alternative fuels under varying conditions of temperature and pressure ». Thesis, Cardiff University, 2010. http://orca.cf.ac.uk/54231/.
Texte intégralPoloni, Roberta. « Heavy alkali metal-intercalated fullerenes under high pressure and high temperature conditions ». Lyon 1, 2007. http://tel.archives-ouvertes.fr/docs/00/19/46/10/PDF/THESIS.pdf.
Texte intégralIn this thesis, we explore the phase diagram of the heavy alkali metal intercalated fullerenes, Rb6C60 and Cs6C60, under high pressure (<50 GPa) and high temperature conditions (from ambient to 1500 K). The work includes a series of X-ray absorption spectroscopy, X-ray diffraction and Raman spectroscopy measurements as well as ab initio DFT calculations under pressure. By coupling both experiments and calculations, we observed that the presence of strong ionic interactions between each molecule and the alkali metal ions, prevents fullerene polymerization under pressure. In the case of Cs6C60, this allows to extend the pressure stability of the C60 molecules more than twice with respect to pristine solid C60. In the case of Rb6C60 a phase transition, is observed at 35 GPa. A pressure induced enhanced deformation of the fullerene molecule in the studied systems has been evidenced. The compressibility of the both crystals has been measured and calculated
Schaffer, Joseph F. « Verification and Adaptation of an Infiltration Model for Water at Various Isothermal Temperature Conditions ». Digital WPI, 1999. https://digitalcommons.wpi.edu/etd-theses/1061.
Texte intégralSeto, Kelsey C. « Hydrogen production from aluminum-water reactions subject to high pressure and temperature conditions ». Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111936.
Texte intégralCataloged from PDF version of thesis.
Includes bibliographical references (pages 75-77).
Aluminum fuel has become an attractive form of energy storage in recent years as it is both a highly abundant and extremely energy dense material. Research has discovered methods of treating aluminum with liquid metal, enabling the aluminum to produce large amounts of hydrogen when oxidized by liquid water. When this fuel reacts with water, it produces hydrogen, heat, and aluminum hydroxide (Al(OH) 3 ). Although this aluminum fuel has already been integrated into an effective mobile hydrogen production source for hydrogen fuel cells, the system size and weight is restricted by the amount of water that is required to react the aluminum. The less water that needs to be carried on board, the better, and the only way to decrease the amount of water that is required to produce hydrogen through aluminum-water reactions is to alter the chemistry of the reaction. This thesis investigates the possibility of manipulating the chemistry of these reactions at high pressures and temperatures to produce aluminum oxyhydroxide (AlOOH) or aluminum oxide (Al203 ), both of which are byproducts of aluminum-water reactions which consume less water than the Al(OH) 3 reaction for the amount of hydrogen produced. A MATLAB simulation was constructed to predict the favorability of each byproduct by analyzing the Gibbs free energy of the reactions as a function of pressure and temperature. This simulation revealed that A100H becomes favorable over Al(OH) 3 at 142.38°C and 387kPa and A120 3 becomes favorable over A100H at 174.21°C and 889kPa in a system with a 200ml volume in which 5g of fuel is reacted. Pressurized tests were also carried out and the experiment results showed that A1OOH was produced from these aluminum-water reactions at 181°C and 1035kPa, proving that it is possible to manipulate these reactions to improve the performance of aluminum fuel as a hydrogen source.
by Kelsey Carolyn Seto.
S.M.
Holmberg, Johanna. « Pressure Temperature Conditions of the Otrøy Opmhacite-Garnet Gneiss, Western Gneiss Region, Skandinavian Caledonides ». Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-256283.
Texte intégralGranat-omphacitförande gnejser från ön Otrøy i Western Gneiss Region (WGR), Norge, Skandinaviska Kaledoniderna, har undersöks i den här studien. WGR är ett av världens mest studerade område för ultrahögtryckmetamorfa bergarter. I den här typen av gnejser förekommer linser av ultrahögtrycksbergarter så som granat-peridotiter och eklogiter. I den studerade Otrøygnejsen förekommer bland annat phengit och omphacit med inneslutningar av sannolika pseudomorfer efter coesit. Detta visar på att Otrøygnejsen troligen har bildats under metamorfos vid ultrahöga tryck. Geotermobarometriundersökningen, baserat på granat + clinopyroxen + phengitsystemet, visar att tryck- och temperaturförhållandena var ca.880 ˚C och 2.2 GPa. Det innebär att gnejsen metamorfoserats inom intervallet karaktäristiskt för högtrycksmetamorfos. Likväl, kan det fastställas att Otrøygnejsen bildats till följd av en djup subduktion under kontinent-kontinentkollision. Den här studien bidrar till en ökad förståelse av processerna som påverkar den kontinentala skorpan vid djup subduktion och vidgar våra kunskaper om den komplexa metamorfa och tektoniska utvecklingen i WGR och de Skandinaviska Kaledoniderna.
Barboza, Felipe Moreira. « STUDY OF VIBRATIONAL PROPERTIES OF THYMIDINE CRYSTAL IN EXTREME CONDITIONS OF PRESSURE AND TEMPERATURE ». Universidade Federal do CearÃ, 2017. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=18956.
Texte intégralThe unit of sugar and base connected by a N-β-glycosyl linkage is named a nucleoside. In the present work the nucleoside thymidine, whose molecular formula is C10N2O5H14, was studied by Raman spectroscopy, subjecting it extreme conditions of pressure and temperature, as well as X ray diffraction measurements. An auxiliary analysis of normal crystal vibration modes was performed using first principles calculations using the B3LYP functional together with the Gaussian bases 6-31G+(d) and potential energy distribution analysis (PED). These results, together with literature data and Raman spectroscopy measurements in several thymidine scattering geometries, allowed the identification of the various normal modes of crystal vibration. X-ray diffraction experiments were performed in the temperature range between 83 and 413 K. Experiments of Raman spectroscopy under extreme temperature conditions (20 to 380 K) were performed in the spectral range of 20 to 3400 cm-1. From the analysis of the results, it is possible to draw some conclusions. (i) The thymidine crystal remained stable throughout the investigated temperature range, indicating that the temperature effect is not sufficient to modify the hydrogen bonds present between the molecules in such a way as to modify the symmetry of the crystal. (ii) The material studied showed some slight changes in the vibrational spectra in the experiment performed at low temperatures, suggesting, if not a structural phase transition, at least some conformational modification of the thymidine molecules. Raman spectra of thymidine crystal were obtained for pressures up to 5.0 GPa in a diamond anvil cell. The results show the presence of anomaly in the Raman spectrum at pressures close to 3.0 GPa. This anomaly is characterized by disappearance of lattice modes, appearance of some internal modes, splitting of high wavenumbers modes, downshift of modes associated with hydrogen bonds, changes in the intensity of internal modes and discontinuities of the slopes of the wavenumbers versus pressure for several Raman modes. This set of modifications was interpreted as consequence of a phase transition undergone by thymidine close to 3.0 GPa. Further, decompression to atmospheric pressure generates the original Raman spectrum, showing that the pressure-induced phase transition undergone by thymidine crystals is reversible. A comparison with results on other nucleosides submitted to high pressure is also furnished.
Quando a pentose (glicose) e uma base nitrogenada unem-se por meio de uma ligaÃÃo N-β glicosÃdica forma-se uma molÃcula denominada de nucleosÃdeo. No presente trabalho o nucleosÃdeo timidina, cuja fÃrmula molecular à C10N2O5H14, foi estudado atravÃs de espectroscopia Raman, submetendo-o a condiÃÃes extremas de pressÃo e de temperatura, alÃm de medidas de difraÃÃo de raios X. Uma anÃlise auxiliar a respeito dos modos normais de vibraÃÃo do cristal foi realizada atravÃs de cÃlculos de primeiros princÃpios utilizando-se o funcional B3LYP em conjunto com as bases gaussianas 6-31G+(d) e anÃlise de distribuiÃÃo de energia potencial (PED). Esses resultados, juntamente com dados da literatura e medidas de espectrocopia Raman em diversas geometrias de esplalhamento na timidina permitiram uma identificaÃÃo dos vÃrios modos normais de vibraÃÃo do cristal. Os experimentos por difraÃÃo de raios X foram realizados no intervalo de temperatura entre 83 e 413 K. Experimentos de espectroscopia Raman sob condiÃÃes extremas de temperatura (20 a 380 K) foram realizados no intervalo espectral compreendido entre 20 e 3400 cm-1. Da anÃlise dos resultados, à possÃvel tirar algumas conclusÃes. (i) O cristal de timidina manteve-se estÃvel em todo o intervalo de temperatura investigado, indicando que o efeito de temperatura nÃo à suficiente para modificar as ligaÃÃes de hidrogÃnio presentes entre as molÃculas de tal forma que haja modificaÃÃo da simetria do cristal. (ii) O material estudado apresentou algumas leves mudanÃas nos espectros vibracionais no experimento realizado a baixas temperaturas, sugerindo, se nÃo uma transiÃÃo de fase estrutural, pelo menos alguma modificaÃÃo conformacional das molÃculas da timidina. Experimentos submetendo o cristal a pressÃes de atà 5 GPa foram realizados utilizando-se uma cÃlula de pressÃo a extremos de diamantes. Os resultados mostraram anomalias nos espectros Raman por volta de 3.0 GPa. Essas anomalias foram caracterizadas pelo desaparecimento de alguns modos de rede, surgimento de alguns modos internos, deslocamento para menores nÃmeros de onda de modos associados a ligaÃÃes de hidrogÃnio e descontinuidades dos coeficientes lineares de vÃrios modos nos grÃficos de nÃmero de onda em funÃÃo da pressÃo. Essa sÃrie de modificaÃÃes foram interpretadas como consequÃncia de uma transiÃÃo de fase sofrida pela timidina por volta de 3.0 GPa. AlÃm disso, a descompressÃo da amostra atà a pressÃo atmosfÃrica mostrou que a transiÃÃo de fase à reversÃvel. TambÃm fornecemos uma comparaÃÃo com resultados de outros nucleosÃdeos submetidos a altas pressÃes.
Bamgbade, Babatunde A. « MEASUREMENTS AND MODELING OF HYDROCARBON MIXTURE FLUID PROPERTIES UNDER EXTREME TEMPERATURE AND PRESSURE CONDITIONS ». VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/3967.
Texte intégralHernandez, Jean-Alexis. « Ab initio modeling of dense water ices at extreme conditions of pressure and temperature ». Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEN028/document.
Texte intégralIn this thesis we study the stability and the properties of pure and NaCl-bearing dense water ices at high pressure (between 5 and 300 GPa) and high temperature (between 300 and 2000 K). To reach these conditions that correspond to the interiors of ocean exoplanets, we employ a theoretical approach based on ab initio molecular dynamics simulations. We show that a detailed analysis of the hydrogen bond dynamics allows to distinguish all the different ice phases presenting a body-centered cubic sub-lattice of oxygen atoms. In particular, we present the first ab initio description of the plastic phase of water ice. We also reveal the multiple transitions that occur in the superionic domain. Next, we show that ice VII' can incorporate up to 5.9 wt% NaCl in its structure at 1600 K. The inclusion of Na+ and Cl- ions enhances the orientation disorder of the water molecules in comparison to the pure ice. From 2.5 wt% NaCl, superionic conduction expands over the entire pressure range studied, and the hydrogen symmetrisation is shifted towards higher pressures. Last, we describe the <110> and <111> screw dislocation core structures of ice X at 80 GPa. This constitutes a first step towards the construction rheological laws for high-pressure cubic ices
Turnbull, Robin William. « Simple molecular systems at extreme conditions ». Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31324.
Texte intégralDionicio, Gabriel Alejandro. « Electrical resistivity of YbRh2Si2 and EuT2Ge2 (T = Co, Cu) at extreme conditions of pressure and temperature ». Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2007. http://nbn-resolving.de/urn:nbn:de:swb:14-1170255664129-64812.
Texte intégralGlazyrin, Konstantin [Verfasser], et Leonid [Akademischer Betreuer] Dubrovinsky. « Iron in oxides, silicates and alloys under extreme pressure-temperature conditions / Konstantin Glazyrin. Betreuer : Leonid Dubrovinsky ». Bayreuth : Universitätsbibliothek Bayreuth, 2011. http://d-nb.info/1018017755/34.
Texte intégralZahoor, Mudasar. « Non-Local Damage Modeling of Rocks under the conditions of High Pressure and High Temperature (HPHT) ». Research Showcase @ CMU, 2011. http://repository.cmu.edu/dissertations/555.
Texte intégralDionicio, Gabriel Alejandro. « Electrical resistivity of YbRh2Si2 and EuT2Ge2 (T = Co, Cu) at extreme conditions of pressure and temperature ». Doctoral thesis, Technische Universität Dresden, 2006. https://tud.qucosa.de/id/qucosa%3A25011.
Texte intégralNauyoks, Stephen Edwin. « Microstructure of nano and micron size diamond-SIC composites sintered under high pressure high temperature conditions ». [Fort Worth, Tex.] : Texas Christian University, 2009. http://etd.tcu.edu/etdfiles/available/etd-10152009-102152/unrestricted/Nauyoks.pdf.
Texte intégralHammer, Jeremiah Thomas. « Plastic Deformation and Ductile Fracture of Ti-6Al-4V under Various Loading Conditions ». The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354700435.
Texte intégralLaing, Norman. « The performance and mechanisms of selected barium sulphate scale inhibitors under various conditions of brine composition and temperature ». Thesis, Heriot-Watt University, 2006. http://hdl.handle.net/10399/191.
Texte intégralCastillo, Rodrigo. « Synthesis of silicon- and germanium-rich phases at high-pressure conditions ». Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-207708.
Texte intégralGoncharov, Aleksey. « Redox - pressure - temperature conditions in the continental upper mantle in relation to C-O-H fluid speciation ». Phd thesis, Université Jean Monnet - Saint-Etienne, 2012. http://tel.archives-ouvertes.fr/tel-00974462.
Texte intégralGaida, Nico Alexander [Verfasser]. « Nanocrystalline ceramics synthesized of highly abundant raw materials under extreme pressure and temperature conditions / Nico Alexander Gaida ». Kiel : Universitätsbibliothek Kiel, 2018. http://d-nb.info/1160938989/34.
Texte intégralAllcock, David. « Investigating the molecular basis of cold temperature and high pressure adapted growth in Photobacterium profundum SS9 ». Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/3859.
Texte intégralCrosby, Jared M. « Particle Size, Gas Temperature, and Impingement Cooling Effects on High Pressure Turbine Deposition in Land Based Gas Turbines from Various Synfuels ». Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1774.pdf.
Texte intégralPeraza, Ávila Jesús Enrique. « Experimental study of the diesel spray behavior during the jet-wall interaction at high pressure and high temperature conditions ». Doctoral thesis, Universitat Politècnica de València, 2020. http://hdl.handle.net/10251/149389.
Texte intégral[ES] El potencial de los motores diesel en términos de robustez, eficiencia y la densidad de energía los ha hecho ser ampliamente usados como generadores de energía y sistemas propulsivos. Específicamente, la atomización de combustible, vaporización y mezcla de aire y combustible tienen un efecto fundamental en el proceso de combustión y, en consecuencia, un impacto directo en la formación de emisiones contaminantes, consumo de combustible y generación de ruido. Dado que la cámara de combustión tiene un espacio limitado con respecto la capacidad de penetración del chorro, el impacto de la pared se considera bastante común en motores de inyección directa diésel, que tienen una influencia relevante en la evolución del chorro y su interacción con el aire circundante y las paredes sólidas. Esto hace de interacción chorro-pared, un factor importante para el proceso de combustión que aún es dificilmente comprendido. En condiciones de arranque en frío, las bajas presiones y temperaturas en la cámara promueven la deposición de combustible en la pared del pistón, lo que conduce a un aumento en los niveles de formación de hidrocarburos no quemados. Además, las tendencias modernas de diseño como el incremento de las presiones de rail en los sistemas de inyección y la progresiva reducción en la cilindrada de los motores, favorecen la aparición de colisiones entre chorro y pared. A pesar de la evidente importancia en la comprensión de este fenómeno y los esfuerzos de los investigadores para alcanzarla, la transitoria naturaleza del proceso de inyección, sus pequeñas escalas de temporales y la complejidad de los fenómenos físicos que tienen lugar en las proximidades de la pared, hacen que la observación directa de esta interacción chorro-pared sea un desafío. Aunque las herramientas computacionales han demostrado ser invaluables en este campo de estudio, la necesidad de datos experimentales confiables para el desarrollo de esos modelos predictivos está muy presente. Esta tesis tiene como objetivo arrojar luz sobre las características fundamentales de la interacción chorro-pared (SWI por sus siglas en inglés) en condiciones de cámara similares a las de un motor diesel. Se colocó una pared plana a diferentes distancias de impacto y ángulos con respecto al jet. De esta manera, dos tipos diferentes de investigaciones experimentales sobre chorros en colisión se llevaron a cabo: se empleó una pared de cuarzo transparente en la cámara para, de forma aislada, analizar las características macroscópicas del chorro en condiciones evaporativas inertes y reactivas, que pueden observarse lateralmente y a través de la pared, gracias al uso de una instalación de alta presión y alta temperatura ópticamente accesible. Esta misma instalación se utilizó en el segundo tipo de experimentos en los que se introdujo una pared de acero inoxidable para capturar adicionalmente el efecto de las condiciones de operación en el flujo de calor entre ésta y el chorro durante los eventos de inyección y combustión y para determinar cómo la evolución del chorro y la llama son afectadas por una situación realista de transferencia de calor. Esta pared fue instrumentada para controlar la temperatura inicial de su superficie expuesta a la cámara y medir su variación con el tiempo, utilizando termopares de alta velocidad. Ensayos en condiciones de chorro libre también se realizaron para proporcionar una base comparativa sólida para esos experimentos.
[CA] El potencial dels motors dièsel en termes de robustesa, eficiència i la densitat d'energia els ha fet ser àmpliament usats com a generadors d'energia i sistemes propulsius. Específicament, l'atomització de combustible, vaporització i barreja d'aire i combustible tenen un efecte fonamental en el procés de combustió i, en conseqüència, un impacte directe en la formació d'emissions contaminants, consum de combustible i generació de soroll. Atès que la cambra de combustió té un espai limitat pel que fa la capacitat de penetració de l'raig, l'impacte de la paret es considera bastant comú en motors d'injecció directa dièsel, que tenen una influència rellevant en l'evolució del doll i la seva interacció amb el aire circumdant i les parets sòlides. Això fa d'interacció doll-paret, un factor important per al procés de combustió que encara és difícilment comprès. En condicions d'arrencada en fred, les baixes pressions i temperatures a la cambra promouen la deposició de combustible a la paret del pistó, el que condueix a un augment en els nivells de formació d'hidrocarburs no cremats. A més, les tendències modernes de disseny com l'increment de les pressions de rail en els sistemes d'injecció i la progressiva reducció en la cilindrada dels motors, afavoreixen l'aparició de col·lisions entre el doll i la paret. Tot i l'evident importància en la comprensió d'aquest fenomen i els esforços dels investigadors per aconseguir-la, la transitòria naturalesa de l'procés d'injecció, les seves petites escales de temporals i la complexitat dels fenòmens físics que tenen lloc en les proximitats de la paret , fan que l'observació directa d'aquesta interacció doll-paret siga un desafiament. Tot i que les eines computacionals han demostrat ser invaluables en aquest camp d'estudi, la necessitat de dades experimentals fiables per al desenvolupament d'aquests models predictius està molt present. Aquesta tesi té com a objectiu donar llum sobre les característiques fonamentals de la interacció doll-paret (SWI per les seues sigles en anglès) en condicions de cambra similars a les d'un motor dièsel. Es va col·locar una paret plana a diferents distàncies d'impacte i angles pel que fa al jet. D'aquesta manera, dos tipus diferents d'investigacions experimentals sobre dolls en col·lisió es van dur a terme: es va emprar una paret de quars transparent a la cambra per, de forma aïllada, analitzar les característiques macroscòpiques del doll en condicions evaporació inerts i reactives, que poden observar lateralment i a través de la paret, gràcies a l'ús d'una instal·lació d'alta pressió i alta temperatura òpticament accessible. Aquesta mateixa instal·lació es va utilitzar en el segon tipus d'experiments en els quals es va introduir una paret d'acer inoxidable per capturar addicionalment l'efecte de les condicions d'operació en el flux de calor entre aquesta i el dull durant els esdeveniments d'injecció i combustió i per determinar com l'evolució del doll i la flama són afectades per una situació realista de transferència de calor. Aquesta paret va ser instrumentada per controlar la temperatura inicial de la seua superfície exposada a la càmera i mesurar la seua variació amb el temps, utilitzant termoparells d'alta velocitat. Assajos en condicions de doll lliure també es van realitzar per proporcionar una base comparativa sòlida per a aquests experiments.
Peraza Ávila, JE. (2020). Experimental study of the diesel spray behavior during the jet-wall interaction at high pressure and high temperature conditions [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/149389
TESIS
Ali, Hatim F. A. « Assessment of lime-treated clays under different environmental conditions ». Thesis, University of Bradford, 2019. http://hdl.handle.net/10454/18313.
Texte intégralGrosjean, Rémi. « Nanomatériaux à base de bore sous conditions extrêmes ». Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066393/document.
Texte intégralIn this PhD work, we develop a way to prepare new nanostructured materials under extreme pressure and temperature conditions (P > 5 GPa et T > 1000 °C). The studied materials are based on a specific element: boron. Indeed, these materials have unique properties. On the one hand, boron allotropes exhibit high hardness and chemical inertness. On the other hand, metal-boron alloys (metal borides) span a wide range of properties, from thermoelectricity (HfB2) to superconductivity (TiB2). We use the synthesis in molten salts to reach nanostructured systems with two components: crystalline boride nanoparticles (ca. 10 nm) embedded in an amorphous boron matrix. High pressure high temperature treatments on these systems enable crystallisation of the amorphous component into unique phases, thus yielding new nanomaterials: boride/borate (HfB2/HfB2O5 or CaB6/CaB2O4) or boride/boron (HfB2/β-B or CaB6/β-B) nanocomposites, representing the first members of new nanomaterials families. In a final step, a specific nanostructured amorphous boron precursor is synthesised in molten salts. It is crystallised under high pressure and temperature. In addition to the first nanostructured occurrence of the epsilon-boron phase, we report two new boron-rich phases, which structure is under resolution. All in all, a new synthetic route is developed at the frontier of nanomaterials chemistry and high pressure and temperature physics, leading to new nanomaterials and structures
Briggs, R. J. « In situ study of polymorphism and melting of metals and compounds under extreme conditions of high pressure and high temperature ». Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1389060/.
Texte intégralEngström, Adam. « Investigation of the metamorphic environment conditions of Persholmen, NE Utö, with SEM generated data ». Thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-92298.
Texte intégralWu, Yi. « Experimental investigation of laminar flame speeds of kerosene fuel and second generation biofuels in elevated conditions of pressure and preheat temperature ». Thesis, Rouen, INSA, 2016. http://www.theses.fr/2016ISAM0011/document.
Texte intégralLaminar flame speed is one of the key parameters for understanding reactivity, diffusivity and exothermicity of fuels. It is also useful to validate both the kinetic chemical mechanisms as well as turbulent models. Although laminar flame speeds of many types of fuels have been investigated over many decades using various combustion methodologies, accurate measurements of laminar flame speeds of multicomponent liquid fuels in high-pressure and high-temperature conditions similar to the operating conditions encountered in aircraft/automobile combustion engines are still required. In this current study, a high-pressure combustion chamber was specifically developed to measure the laminar flame speed of multicomponent liquid fuels such as kerosene and second generation of biofuels. The architecture of the burner is based on a preheated premixed Bunsen flame burner operated in elevated pressure and temperature conditions. The optical diagnostics used to measure the laminar flame speed are based on the detection of the flame contour by using OH* chemiluminescence, OH- and acetone/aromatic- Planar laser induced fluorescence (PLIF). The laminar flame speed of gaseous CH4/air and acetone/air premixed laminar flames were first measured for validating the experimental setup and the measurement methodologies. Then, the laminar flame speeds of kerosene or surrogate fuels (neat kerosene compounds, LUCHE surrogate kerosene and Jet A-1) were investigated and compared with simulation results using detailed kinetic mechanisms over a large range of conditions including pressure, temperature and equivalence ratio. The last part of the thesis was devoted to study the effect of oxygenated compounds contained in the second generation of biofuels on the laminar flame speeds. After measuring the laminar flame speeds of various oxygenated components present in partially hydro-processed lignocellulosic biomass pyrolysis oils, the effect of these oxygenates on the flame speeds of these fuels were quantitatively investigated
Philippe, Julien. « Développement d'une presse portative pour les études in et ex situ sous conditions extrêmes de pression, température et déformation ». Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066008.
Texte intégralHigh pressures are essential in several scientific field. This will be the case in this thesis with the development of a new device enabling new possibilities tomography and deformation under high pressure and high temperature. It brings the possibility of further scientific studies in the various disciplines that are Earth science, mechanical chemistry, physics of materials and liquids physics
Zhang, Haiwa. « Experimental investigation of the phase diagram of ammonia monohydrate at high pressure and temperature ». Electronic Thesis or Diss., Sorbonne université, 2019. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2019SORUS410.pdf.
Texte intégralThis thesis in experimental physics investigates the phase diagram of ammonia monohydrate (AMH) at high pressure (0
Grosjean, Rémi. « Nanomatériaux à base de bore sous conditions extrêmes ». Electronic Thesis or Diss., Paris 6, 2016. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2016PA066393.pdf.
Texte intégralIn this PhD work, we develop a way to prepare new nanostructured materials under extreme pressure and temperature conditions (P > 5 GPa et T > 1000 °C). The studied materials are based on a specific element: boron. Indeed, these materials have unique properties. On the one hand, boron allotropes exhibit high hardness and chemical inertness. On the other hand, metal-boron alloys (metal borides) span a wide range of properties, from thermoelectricity (HfB2) to superconductivity (TiB2). We use the synthesis in molten salts to reach nanostructured systems with two components: crystalline boride nanoparticles (ca. 10 nm) embedded in an amorphous boron matrix. High pressure high temperature treatments on these systems enable crystallisation of the amorphous component into unique phases, thus yielding new nanomaterials: boride/borate (HfB2/HfB2O5 or CaB6/CaB2O4) or boride/boron (HfB2/β-B or CaB6/β-B) nanocomposites, representing the first members of new nanomaterials families. In a final step, a specific nanostructured amorphous boron precursor is synthesised in molten salts. It is crystallised under high pressure and temperature. In addition to the first nanostructured occurrence of the epsilon-boron phase, we report two new boron-rich phases, which structure is under resolution. All in all, a new synthetic route is developed at the frontier of nanomaterials chemistry and high pressure and temperature physics, leading to new nanomaterials and structures
Ngeleka, Tholakele Prisca. « Sulphur dioxide capture under fluidized bed combustion conditions / Tholakele Prisca Ngeleka ». Thesis, North-West University, 2005. http://hdl.handle.net/10394/1416.
Texte intégralThesis (M.Sc. (Chemical Engineering))--North-West University, Potchefstroom Campus, 2006.
Biggs, Timothy James. « Studies of crystalline organic molecular materials under extreme conditions ». Thesis, University of Oxford, 2006. http://ora.ox.ac.uk/objects/uuid:51dae806-2954-4ea7-a3cb-1980ecb53e98.
Texte intégralNilaphai, Ob. « Vaporization and Combustion Processes of Alcohols and Acetone-Butanol-Ethanol (ABE) blended in n-Dodecane for High Pressure-High Temperature Conditions : Application to Compression Ignition Engine ». Thesis, Orléans, 2018. http://www.theses.fr/2018ORLE2020/document.
Texte intégralThe growing concern in recent decades, linked to the depletion of oil resources and global warming by greenhouse gases has increased the interest of butanol as an alternative fuel in the transport sector. However, the low yield of production and separation processes still prevents its commercialization as a fuel. Therefore, the intermediate fermentation mixture of butanol production, Acetone-Butanol-Ethanol (ABE), is increasingly considered as a potential alternative fuel because of its similar properties to butanol and its advantages in terms of the energy and cost in the separation process.The context of this work aims to study the impact of fuel properties on the spray and combustion processes of ABE mixture and alcohol fuels, blended with the diesel surrogate fuel, n-dodecane, in different volume ratio from 20% to 50%. A new combustion chamber called "New One Shot Engine," was designed and developed to reach the high-pressure and high temperatureconditions of "Spray-A" (60 bar, 800-900 K and 22.8 kg/m³) defined by the Engine Combustion Network (ECN).The macroscopic spray and combustion parameters were characterized by using the several optical techniques (extinction,Schlieren, chemiluminescence of OH*) under non-reactive (pure Nitrogen) and reactive (15% of oxygen) conditions. These experimental results not only made it possible to study the molecular oxygen impact and provide a new accurate database,but also to affirm the possibility of using ABE up to 20% by volume in compression-ignition engines, as its spray and combustion characteristics similar to conventional diesel fuel
Mathison, Randall Melson. « Experimental and Computational Investigation of Inlet Temperature Profile and Cooling Effects on a One and One-Half Stage High-Pressure Turbine Operating at Design-Corrected Conditions ». The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1250281163.
Texte intégralGross-Lorgouillux, Marion. « Zéolithisation de cendres volantes de charbon dans des conditions douces de température et de pression ». Mulhouse, 2007. https://www.learning-center.uha.fr/opac/resource/zeolithisation-de-cendres-volantes-de-charbon-dans-des-conditions-douces-de-temperature-et-de-pressi/BUS4101683.
Texte intégralThe amount of fly ashes (FAs) produced by the coal combustion in thermal power stations is huge, and even if part of these FAs is reused, their applications have a low-added-value. As the FAs are rich in Si and Al, they can be seen as potential sources for the synthesis of zeolites. These aluminosilicate materials are microporous and display a high added value. Recently, many studies have been devoted to the conversion of FAs into various zeolites. Generally, the FA transformation is performed by a hydrothermal synthesis close or above 100 °C and at autogeneous pressure. The originality of this study is the development of a cost-saving process allowing the FA transformation into zeolite by a hydrothermal reaction at low temperature (below 50 °C) and at atmospheric pressure. The FAs were first characterised by different techniques, the most important objective being the determination of their mineralogical composition (quartz, mullite and amorphous phase) but also of their reactivity. Then, the synthesis consists simply in the addition of a NaOH solution to the FAs. The needed NaOH and water amounts were optimised in order to form an X-type faujasite, the Al2O3/SiO2 ratio (x) of the synthesis medium being fixed by the chemical composition of the FAs. Using this composition (1SiO2: xAl2O3: 3,8NaOH: 73,5H2O), the transformation kinetics of the FAs were studied at 30 and 50 °C by different methods (XRD, nitrogen adsorption, solid state NMR, atomic absorption spectroscopy, and SEM), and a transformation mechanism is proposed. Whatever the temperature and the synthesis time, the solid obtained is a mixture of faujasite, and residual quartz, mullite and amorphous phase from the FAs, but it contains also traces of two other zeolites, namely NaP1 zeolite and chabazite. The temperature increase from 30 to 50 °C speeds up the reaction, but finally, the maximal conversion rates reached at both temperatures are close: about 25 to 30 %. Other experiments were performed in order to increase the conversion yield, i. E. The addition of silica to the synthesis medium or an indirect synthesis method consisting in an acid treatment (HCl) of the FAs prior to the classic hydrothermal reaction. These experiments allowed increasing the conversion rate which is, in the most favourable case, above 50 % offaujasite in the final dried product of the synthesis
Hrubiak, Rostislav. « Exploring Thermal and Mechanical Properties of Selected Transition Elements under Extreme Conditions : Experiments at High Pressures and High Temperatures ». FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/696.
Texte intégralAhuja, Nandita. « Impact of operating conditions on thermal hydrolysis pre-treated digestion return liquor ». Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/56647.
Texte intégralMaster of Science
Lotti, P. « CANCRINITE-GROUP MINERALS AT NON-AMBIENT CONDITIONS : A MODEL OF THE ELASTIC BEHAVIOR AND STRUCTURE EVOLUTION ». Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/231573.
Texte intégralParakala, Shilpha R. « EIS Investigation of Carbon Dioxide and Hydrogen Sulfide Corrosion Under Film Forming Conditions ». Ohio University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1125871582.
Texte intégralKrstulovic, Marija [Verfasser], Max [Akademischer Betreuer] Wilke, Sakura [Akademischer Betreuer] Pascarelli, Jörg [Gutachter] Erzinger, Sakura [Gutachter] Pascarelli et Guillaume [Gutachter] Morard. « Local structure of network formers and network modifiers in silicate melts at high pressure and temperature conditions / Marija Krstulovic ; Gutachter : Jörg Erzinger, Sakura Pascarelli, Guillaume Morard ; Max Wilke, Sakura Pascarelli ». Potsdam : Universität Potsdam, 2021. http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-516415.
Texte intégralKolesnikov, Anton. « Experimental investigation of hydrocarbon formation and transformation under Earth´s upper mantle conditions ». Doctoral thesis, KTH, Kraft- och värmeteknologi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-27017.
Texte intégralQC 20101203
Lührs, Hanna [Verfasser], R. X. [Akademischer Betreuer] Fischer et Thorsten M. [Akademischer Betreuer] Gesing. « The influence of boron on the crystal structure and properties of mullite : Investigations at Ambient, High-Pressure, and High-Temperature Conditions / Hanna Lührs. Gutachter : Reinhard X. Fischer ; Thorsten M. Gesing. Betreuer : Reinhard X. Fischer ». Bremen : Staats- und Universitätsbibliothek Bremen, 2013. http://d-nb.info/1072078511/34.
Texte intégralTello, Oquendo Fernando Mauricio. « Study of scroll compressors with vapor-injection for heat pumps operating in cold climates or in high-temperature water heating applications ». Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/120473.
Texte intégral[CA] Aquesta tesi doctoral presenta un estudi de compressors scroll amb injecció de vapor (SCVI) per a bombes de calor que operen en climes freds o per a aplicacions d'escalfament d'aigua a alta temperatura. Per a això, es va comparar experimentalment un SCVI amb un compressor de dues etapes de pistons (TSRC) treballant amb R-407C en condicions extremes. La comparació es va realitzar en termes d'eficiències del compressor, capacitat, COP i rendiments estacionals tant per al mode calefacció com per al mode refrigeració. Els resultats proporcionen una idea general sobre el rang d'aplicació dels compressors estudiats i sobre les diferències en els rendiments dels compressors. No obstant això, es van identificar diverses limitacions en la caracterització dels compressors i en l'anàlisi del cicle. Això va motivar a aprofundir en l'estudi del cicle de compressió de dues etapes i els seus components. El següent pas va ser realitzar una anàlisi teòrica dels cicles de compressió de dues etapes per a aplicacions de calefacció, on es va identificar la pressió intermèdia i la relació d'injecció com els paràmetres del sistema més influents sobre el COP. La pressió intermèdia es va optimitzar per a dues configuracions d'injecció (tanc de separació i economitzador) utilitzant diversos refrigerants. Basant-se en els resultats de l'optimització, es va proposar una correlació que permet obtindre la pressió intermèdia òptima del cicle, considerant la influència del subrefredament a l'eixida del condensador. A més, es va analitzar la influència del disseny dels components del sistema sobre el COP del cicle. Posteriorment, l'estudi es va aprofundir a nivell de components. El factor més crític en el sistema és el rendiment del compressor. Per tant, el següent pas va ser avaluar la influència de diversos sistemes de compressió amb injecció de vapor sobre el COP. Es van prendre en compte tres tecnologies de compressors, un SCVI, un TSRC i un compressor scroll de dues etapes (TSSC). Aquestes tecnologies de compressors van ser caracteritzades i modelades per a estudiar el seu rendiment. Per a això, es va proposar una nova metodologia per a caracteritzar compressors scroll amb injecció de vapor. Aquesta metodologia permet avaluar el rendiment del compressor independentment del mecanisme d'injecció que s'utilitza en el cicle. Es va identificar una correlació lineal entre la relació d'injecció de refrigerant i la relació de compressió intermèdia. Aquesta correlació s'utilitza per a determinar el flux màssic d'injecció en funció de la pressió intermèdia. Posteriorment, es va proposar un model semi-empíric de compressors scroll i una metodologia per a estendre aquest model per a compressors scroll amb injecció de vapor. Els models van ser ajustats i validats utilitzant dades experimentals de quatre compressors scroll treballant amb R-290 i un SCVI treballant amb R-407C. Finalment, es va comparar un SCVI amb dos compressors de dues etapes, un TSSC i un TSRC, treballant en condicions extremes. Es va optimitzar la relació de volums dels compressors de dues etapes. Els resultats mostren que, en les condicions nominals de funcionament (Te=-15 °C, Tc=50 °C), la relació de volums òptima del TSSC és 0.58, i del TSRC és 0.57. El TSSC aconsegueix un COP 6% major que el SCVI i un COP 11.7% major que el TSRC. Sota un ampli rang de condicions d'operació, el SCVI presenta una millor eficiència i COP per a relacions de pressió inferiors a 5. Per a relacions de pressió més altes, el TSSC presenta millor rendiment i aconsegueix una temperatura de descàrrega més baixa. Es conclou que el SCVI és una solució fàcil d'implementar, des del punt de vista del mecanitzat, i que permet estendre el mapa de treball dels compressors d'una etapa. No obstant això, els resultats mostren que la compressió en dues etapes aconsegueix millorar en major mesura el COP del cicle i la capacitat, amb una major reducció de la
[EN] This Ph.D. thesis presents a study of scroll compressors with vapor-injection (SCVI) for heat pumps operating in cold climates or in high-temperature water heating applications. To do so, firstly, an SCVI was experimentally compared with a two-stage reciprocating compressor (TSRC) working with R-407C under extreme conditions. The comparison was made in terms of compressor efficiencies, capacity, COP, and seasonal COP, both for heating and cooling modes. The results give a general idea about the application range of the studied compressors and the differences in the compressors' performance. Nevertheless, several restrictions in the compressors' characterization and the cycle analysis were identified. This motivated us to deepen in the study of the two-stage compression cycle and its components. The next step was performing a theoretical analysis of two-stage compression cycles for heating applications, where the intermediate pressure and the injection ratio were identified as the most influential system parameters on the COP. The intermediate pressure was optimized for two vapor-injection configurations (flash tank and economizer) using several refrigerants. Based on the optimization results, a correlation was proposed that allows obtaining the optimal intermediate pressure of the cycle, considering the influence of the subcooling at the condenser outlet. In addition, a theoretical analysis of the influence of the design of the system components on the COP of the cycle was performed. Once the thermodynamic analysis of the two-stage cycle was carried out, the study was deepened at the component level. The most critical factor in the system is the compressor performance. Hence, the next step was evaluating the influence of several compression systems with vapor-injection on the COP. Three compressor technologies were taken into account, an SCVI, a TSRC and a two-stage scroll compressor (TSSC). These compressor technologies were characterized and modeled in order to study their performance. To do so, a new methodology to characterize SCVI was proposed. This methodology allows evaluating the compressor performance independently of the injection mechanism used in the cycle. A linear correlation was identified between the refrigerant injection ratio and the intermediate compression ratio. This correlation is used to determine the injection mass flow as a function of the intermediate pressure. Then, a semi-empirical model of scroll compressors and a methodology to extend the model for scroll compressors with vapor-injection was proposed. The models were adjusted and validated using experimental data from four scroll compressors working with R-290 and an SCVI compressor working with R-407C. Finally, an SCVI was compared with two two-stage compressors, a TSSC, and a TSRC, working in extreme conditions. The displacement ratio of the two-stage compressors was optimized. Results show that, at the nominal operating conditions (Te=-15 °C, Tc=50 °C), the optimal displacement ratio of the TSSC is 0.58, and of the TSRC is 0.57. The TSSC achieves 6% larger COP than the SCVI and 11.7% larger COP than the TSRC. Under a wide range of operating conditions, the SCVI presents a better efficiency and COP for pressure ratios below 5. For higher-pressure ratios, the TSSC presents better performance and achieves lower discharge temperature. It is concluded that the SCVI is an easy solution to implement from the point of view of machining, which allows extending the working map of the single-stage compressors. However, the results show that the two-stage compression technology gets further improve the COP of the cycle and the capacity, with a greater reduction of the discharge temperature operating under extreme conditions.
I thank the financial support provided by the Secretaría de Educación Superior, Ciencia, Tecnología e Innovación (SENESCYT) of Ecuador, through the international scholarship program for postgraduate studies “Convocatoria Abierta 2013 Segunda Fase, Grant No 2015-AR37665”.
Tello Oquendo, FM. (2019). Study of scroll compressors with vapor-injection for heat pumps operating in cold climates or in high-temperature water heating applications [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/120473
TESIS
Plennevaux, Cécile. « Etude des risques de corrosion et de rupture différée des aciers en présence d'H2S dans les conditions d'exploration de pétrole et de gaz à haute pression et haute température ». Thesis, Lyon, INSA, 2012. http://www.theses.fr/2012ISAL0101.
Texte intégralThe production of high pressure (HP) and high temperature (HT) wells has considerably increased in the last decade. It is therefore needed to reassess the risks of corrosion in always more severe environments. This work was three fold to better assess the risk of Sulfide Stress Cracking (SSC) in these environments. Firstly, there was a need to improve prediction methods for the evaluation of HP/HT environments severity, especially the in situ pH calculation. A model was which taking into account the non-ideal behaviour of gas and liquid phases in equilibrium. The determination of the in situ pH and the acid gas fugacity at high pressure and high temperature is more accurate. In a second part of the work, the impact of CO2 partial pressure (PCO2) on surface reactions and hence on the risk of SSC was examined. Electrochemical and hydrogen permeation measurements in the absence of an iron sulphide film showed that CO2 induces an increase of both cathodic reactions kinetics and hydrogen charging in the steel, especially at low H2S partial pressure (PH2S). In the last part of this work, SSC tests were performed at constant pH and constant PH2S, with various PCO2 from 0 to 100 bar. The objective was to experimentally confirm that increasing PCO2 increases the SSC risk, as inferred from the electrochemical study. Unfortunately, experimental artefacts linked with autoclave test conditions did not lead to clear conclusions on this point. However, this work shows that conventional tools might lead to underestimate SSC risks at high PCO2 and low PH2S. In these specific conditions, the new results presented in this report may contribute to improve materials selection criteria for high pressure and high temperature conditions
Plennevaux, Cécile. « Etude des risques de corrosion et de rupture différée des aciers en présence d'H2S dans les conditions d'exploration de pétrole et de gaz à haute pression et haute température ». Electronic Thesis or Diss., Lyon, INSA, 2012. http://www.theses.fr/2012ISAL0101.
Texte intégralThe production of high pressure (HP) and high temperature (HT) wells has considerably increased in the last decade. It is therefore needed to reassess the risks of corrosion in always more severe environments. This work was three fold to better assess the risk of Sulfide Stress Cracking (SSC) in these environments. Firstly, there was a need to improve prediction methods for the evaluation of HP/HT environments severity, especially the in situ pH calculation. A model was which taking into account the non-ideal behaviour of gas and liquid phases in equilibrium. The determination of the in situ pH and the acid gas fugacity at high pressure and high temperature is more accurate. In a second part of the work, the impact of CO2 partial pressure (PCO2) on surface reactions and hence on the risk of SSC was examined. Electrochemical and hydrogen permeation measurements in the absence of an iron sulphide film showed that CO2 induces an increase of both cathodic reactions kinetics and hydrogen charging in the steel, especially at low H2S partial pressure (PH2S). In the last part of this work, SSC tests were performed at constant pH and constant PH2S, with various PCO2 from 0 to 100 bar. The objective was to experimentally confirm that increasing PCO2 increases the SSC risk, as inferred from the electrochemical study. Unfortunately, experimental artefacts linked with autoclave test conditions did not lead to clear conclusions on this point. However, this work shows that conventional tools might lead to underestimate SSC risks at high PCO2 and low PH2S. In these specific conditions, the new results presented in this report may contribute to improve materials selection criteria for high pressure and high temperature conditions
Cheng, Yu-Cheng, et 鄭羽成. « The Kinetic Analysis of Brownian Motors Suffered Periodic Force in Periodic Various Temperature Conditions ». Thesis, 2008. http://ndltd.ncl.edu.tw/handle/58695612198722236155.
Texte intégral國立成功大學
工程科學系碩博士班
96
The concept of Brownian motors may use for to explain how molecular motors take mechanochemistry coupling of the motion to achieve the directive movement when it subjects to thermal fluctuation. The conformation of molecular motors is changed by the mechanochemistry coupling of the motion with hydrolysis of ATP and the binding of ATP. It means that molecular motors generate the change of potential energy and mechanical motion. In order to Brownian motors produce motion in one direction, and increasing the average velocity effectively. This paper uses the coupling model of Rocking ratchet and Diffusion ratchet to simulate the movement situation of Brownian motors. The Fokker-Planck equation is the governing equation in this paper, it can be used to solve the probability and the probability flux in different temperature conditions and it also used to calculate working model with potential energy switches between an on and an off state by Robust numerical algorithm in the reference[11]. In the algorithm a continuous Markov process is discretized as a jump process and the jump rates are derived from local solution of the continuous systems which contain the property of detailed balance. This paper used MATLAB 7.0 to calculate the equations and the numerical algorithm to analyze what kinds of different temperature conditions influences the average velocities of Brownian motors to achieve the maximum value, and to discuss the average velocities, the effective diffusion coefficients of Brownian motors with increasing the amplitude of potential energy under external force.
Lee, I.-Jung, et 李宜容. « Application of High Temperature and High Pressure with Metallic Catalysts for Producing Various Carbon Nanomaterials ». Thesis, 2010. http://ndltd.ncl.edu.tw/handle/08328519270275741986.
Texte intégral高苑科技大學
化工與生化工程研究所
98
Nano-structured materials have been synthesized by a self-heating detonation process using explosives (TNT, HMX) for providing the need of high temperatures and high shock waves in the presence of metallic-containing catalysts. These results show that catalyzed-blast process is possible for a cheaper process and it is aiso an alternative compared to these high energy and hardware intensive processes to assemble nano-sized carbon nanomaterials. The products of carbon nanoparticles, nanotubes and nanocaosules are characterized by XRD, TEM, HR-TEM, FEG-TEM, EDS and Raman techniques. This research presents the use of this special system to study the catalytic detonation process and the effect of reaction conditions on conditions and the catalytic convevsion of energetic explosives into nano materials. The experimental results show that TNT explosive over the CeO2 and TiO2 metal compounds can be converted into metallic nanoparticles due to the fast decomposition with a reduction reaction after detonation which plays an important role for the growth of different size of carbon nanocapsules. The morphology of carbon nanostructures varied with the reaction conditions such as catalyst type, explosive structure, recipes of reactant composition with the use of different carbon cource. The results carried out using an HMX explosive show no tubular structures but with a lot of disordered amorphous carbon with only little spherical carbon nanoparticles. In the case of Ce-catalyzed detonation, clusters of carbon capsules with some nanocarbon tubes. For Ti-catalyzed system it is interesting that such a detonation process can produce it can be used to feasible operation to synthesis hollow carbon nanocapsules. In this research, a laboratory self-heating process has been successfully designed and a more effective synthesis of carbon nano-materials using TNT and HMX energetic materials in relation to the catalysis-assisted detonation. This approach involving bottom-up nanotechnology is universal and low-cost, and especially it has the potential ability to convert waste energetic explosives to form highly valuable materials, as well as providing the suitable alternatives to reuse the energetic explosive further.