Dissertationen zum Thema „Gases in“
Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an
Machen Sie sich mit Top-50 Dissertationen für die Forschung zum Thema "Gases in" bekannt.
Neben jedem Werk im Literaturverzeichnis ist die Option "Zur Bibliographie hinzufügen" verfügbar. Nutzen Sie sie, wird Ihre bibliographische Angabe des gewählten Werkes nach der nötigen Zitierweise (APA, MLA, Harvard, Chicago, Vancouver usw.) automatisch gestaltet.
Sie können auch den vollen Text der wissenschaftlichen Publikation im PDF-Format herunterladen und eine Online-Annotation der Arbeit lesen, wenn die relevanten Parameter in den Metadaten verfügbar sind.
Sehen Sie die Dissertationen für verschiedene Spezialgebieten durch und erstellen Sie Ihre Bibliographie auf korrekte Weise.
Ozturk, Bahtiyar. „Removal of acidic gases from flue gases using membrane contactors“. Thesis, University of Salford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265396.
Der volle Inhalt der QuelleMcGinley, Susan. „Measuring Soil Gases“. College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 1993. http://hdl.handle.net/10150/622349.
Der volle Inhalt der QuelleWhitehead, Thomas Michael. „Interacting Fermi gases“. Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/274548.
Der volle Inhalt der QuelleCunje, Alwin. „Noble gases and catalysis“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0012/NQ59125.pdf.
Der volle Inhalt der QuelleSadeghzadeh, Kayvan. „Spin polarised Fermi gases“. Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610744.
Der volle Inhalt der QuelleGiovanelli, Debora. „Electrochemical detection of gases“. Thesis, University of Oxford, 2004. http://ora.ox.ac.uk/objects/uuid:fd447153-b6dd-4be1-aae5-4ece5dc36856.
Der volle Inhalt der QuelleMadeira, Lucas 1991. „Many-body systems : heavy rare-gases adsorbed on graphene substrates and ultracold Fermi gases = Sistemas de muitos corpos: gases nobres pesados adsorvidos em substratos de grafeno e gases de Fermi ultrafrios“. [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/276942.
Der volle Inhalt der QuelleDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
Made available in DSpace on 2018-08-28T00:18:16Z (GMT). No. of bitstreams: 1 Madeira_Lucas_M.pdf: 4273856 bytes, checksum: 8543c0dd916e2ec3fc638a5d31b32787 (MD5) Previous issue date: 2015
Resumo: Nessa dissertação nós investigamos dois sistemas de muitos corpos. Na primeira parte nós escolhemos uma abordagem clássica para estudar a adsorção de gases nobres pesados, Ne, Ar, Kr, Xe e Rn, em substratos de grafeno. Nós apresentamos evidências de camadas adsorvidas comensuradas, as quais dependem fortemente da simetria do substrato, para duas estruturas: camadas de Ne na rede sqrt{7} X sqrt{7} e Kr na rede sqrt{3} X sqrt{3}. Para estudar o derretimento nós introduzimos um parâmetro de ordem e sua susceptibilidade. O calor específico e a susceptibilidade em função da temperatura foram calculados para os gases nobres pesados em diversas densidades. A posição e largura característica dos picos do calor específico e da susceptibilidade foram determinadas. Finalmente, nós investigamos a distância dos primeiros vizinhos e a distância entre a camada e o substrato, identificando contribuições relacionadas aos picos do calor específico e da susceptibilidade. A segunda parte da dissertação trata de uma linha de vórtice no gás unitário de Fermi. Gases fermiônicos ultrafrios são notáveis devido à possibilidade experimental de variar as interações interpartículas através de ressonâncias de Feshbach, o que possibilita a observação do crossover BCS-BEC. No meio do crossover encontra-se um estado fortemente interagente, o gás unitário de Fermi. Uma linha de vórtice corresponde a uma excitação desse sistema com unidades de circulação quantizadas. Nós construímos funções de onda, inspiradas na função BCS, para descrever o estado fundamental e também o sistema com uma linha de vórtice. Nossos resultados para o estado fundamental elucidam aspectos da geometria cilíndrica do problema. O perfil de densidade é constante no centro do cilindro e vai a zero suavemente na borda. Nós separamos a contribuição devido à parede da energia do estado fundamental e determinamos a energia por partícula do bulk, epsilon_0=(0.42 +- 0.01) E_{FG}. Nós também calculamos o gap superfluído para essa geometria, Delta=(0.76 +- 0.01) E_{FG}. Para o sistema com a linha de vórtice nós obtivemos o perfil de densidade, o qual corresponde a uma densidade não nula no centro do vórtice, e a energia de excitação por partícula, epsilon_{ex}=(0.0058 +- 0.0003) E_{FG}. Os métodos empregados nessa dissertação, Dinâmica Molecular, Monte Carlo Variacional e Monte Carlo de Difusão, nos dão uma base sólida para a investigação de sistemas relacionados, e outros sistemas, de muitos corpos no futuro
Abstract: In this dissertation we investigated two many-body systems. For the first part we chose a classical approach to study the adsorption of heavy rare-gases, Ne, Ar, Kr, Xe and Rn, on graphene substrates. We presented evidences of commensurate adlayers, which depend strongly on the symmetry of the substrate, for two structures: Ne adlayers in the sqrt{7} X sqrt{7} superlattice and Kr in the sqrt{3} X sqrt{3} lattice. In order to study the melting of the system we introduced an order parameter, and its susceptibility. The specific heat and susceptibility as a function of the temperature were calculated for the heavy noble gases at various densities. The position and characteristic width of the specific heat and susceptibility peaks of these systems were determined. Finally, we investigated the first neighbor distance and the distance between the adlayer and the substrate, identifying contributions related to specific heat and melting peaks. The second part of the dissertation deals with a vortex line in the unitary Fermi gas. Ultracold Fermi gases are remarkable due to the experimental possibility to tune interparticle interactions through Feshbach resonances, which allows the observation of the BCS-BEC crossover. Right in the middle of the crossover lies a strongly interacting state, the unitary Fermi gas. A vortex line corresponds to an excitation of this system with quantized units of circulation. We developed wavefunctions, inspired by the BCS wavefunction, to describe the ground state and also for a system with a vortex line. Our results for the ground state elucidate aspects of the cylindrical geometry of the problem. The density profile is flat in the center of the cylinder and vanishes smoothly at the wall. We were able to separate from the ground state of the system the wall contribution and we have determined the bulk energy as epsilon_0=(0.42 +- 0.01) E_{FG} per particle. We also calculated the superfluid pairing gap for this geometry, Delta=(0.76 +- 0.01) E_{FG}. For the system with a vortex line we obtained the density profile, which corresponds to a non-zero density at the core, and the excitation energy, epsilon_{ex}=(0.0058 +- 0.0003) E_{FG} per particle. The methods employed in this dissertation, Molecular Dynamics, Variational Monte Carlo and Diffusion Monte Carlo, give us a solid basis for the investigation of related and other many-body systems in the future
Mestrado
Física
Mestre em Física
2012/24195-2
FAPESP
Teague, Kenneth Grayson. „Predictive dynamic model of a small nonisothermal pressure swing air separation process /“. Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
Der volle Inhalt der QuelleKreslavskiy, Dmitry Michael. „Lorentz Lattice Gases on Graphs“. Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/6423.
Der volle Inhalt der QuelleAsatani, Haruki. „Solubility of gases in liquids“. Thesis, University of Ottawa (Canada), 1986. http://hdl.handle.net/10393/4643.
Der volle Inhalt der QuelleJawad, Shadwan Hamid. „Thermal conductivity of polyatomic gases“. Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367922.
Der volle Inhalt der QuelleClark, D. „Electrochemical sensors for medical gases“. Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382605.
Der volle Inhalt der QuelleLucas, A. K. „Electron loss process in gases“. Thesis, Swansea University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637958.
Der volle Inhalt der QuelleHart, J. „Separation of gases by adsorption“. Thesis, University of Bath, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234617.
Der volle Inhalt der QuelleMeehan, Nicola J. „Continuous reactions in compressed gases“. Thesis, University of Nottingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288085.
Der volle Inhalt der QuelleMcLaughlin, J. G. „Chemistry in liquid noble gases“. Thesis, University of Nottingham, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356030.
Der volle Inhalt der QuelleCarter, Daniel N. „Continuous reactions in dense gases“. Thesis, University of Nottingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416386.
Der volle Inhalt der QuelleAssafiri, T. I. „The electrochemical reduction of gases“. Thesis, University of Newcastle Upon Tyne, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370620.
Der volle Inhalt der QuelleChoi, Doowon. „Ultrasound propagation in various gases“. Thesis, University of Warwick, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250087.
Der volle Inhalt der QuelleBauer, Marianne Sigrid. „Ultracold gases in low dimensions“. Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708055.
Der volle Inhalt der QuelleOktel, Mehmet Özgür 1974. „Optical excitations in cold gases“. Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8276.
Der volle Inhalt der QuelleIncludes bibliographical references (leaves 93-96).
In this thesis, we study the effects of interparticle interactions on the optical spectrum of cold gases. We first consider homogenous gas in the weak excitation regime and find that the optical spectrum of a system of Bosons is highly sensitive to interactions. We find that optical excitations, at temperatures low enough for the thermal de Broglie wavelength to be larger than the scattering length, become collective modes. We study collective affects in the optical spectrum both above and below Bose-Einstein condensation, and show that the spectrum acquires a doublet structure when the condensate forms. We present a detailed theory of spectral shift and an estimate of some of the broadening effects. We derive a sum rule for the average frequency shift of an optical spectrum and investigate the basic conservation laws and symmetries of the system lying at the basis of this sum rule. We also compare the sum rule for the optical spectrum with the f-sum rule for the density-density correlation function. Finally we derive a transport equation for the optical modes in a dilute Bose system, which allows us to study the non-linear response to the excitation field. We map the problem onto the dynamics of two interacting anisotropic spins, and calculate the precession frequencies exactly both below and above Bose condensation. We demonstrate a relation between Rabi oscillations and internal Josephson oscillations, and find that an analogue of the internal Josephson effect exists in a non-condensed system.
(cont.) We also derive the transport equation for a dilute Fermi system and find that the dependence of the precession frequencies on interparticle interactions is very weak for fermions.
by Mehmet Özgür Oktel.
Ph.D.
Mokrani, Touhami. „Transport of gases across membranes“. Thesis, Peninsula Technikon, 2000. http://hdl.handle.net/20.500.11838/878.
Der volle Inhalt der QuelleOxygen transport across biofilms and membranes may be a limiting factor in the operation of a membrane bio-reactor. A Gradostat fungal membrane bio-reactor is one in which fungi are immobilized within the wall of a porous polysulphone capillary membrane. In this study the mass transfer rates of gases (oxygen and carbon dioxide) were investigated in a bare membrane (without a biofilm being present). The work provides a basis for further transport study in membranes where biomass is present. The diaphragm-cell method can be employed to study mass transfer of gases in flat-sheet membranes. The diaphragm-cell method employs two well-stirred compartments separated by the desired membrane to be tested. The membrane is maintained horizontally. -The gas (solute) concentration in the lower compartment is measured versus time, while the concentration in the upper liquid-containing compartment is maintained at a value near zero by a chemical reaction. The resistances-in-series model can be used to explain the transfer rate in the system. The two compartments are well stirred; this agitation reduces the resistances in the liquid boundary layers. Therefore it can be assumed that in this work the resistance in the membrane will be dominating. The method was evaluated using oxygen as a test. The following factors were found to influence mass transfer coefficient: i) the agitation in the two compartments; ii) the concentration of the reactive solution and iii) the thickness of the membrane.
Savikko, M. (Mikko). „Efimov states in ultracold gases“. Master's thesis, University of Oulu, 2014. http://urn.fi/URN:NBN:fi:oulu-201403111157.
Der volle Inhalt der QuelleShteynas, Boris. „Spin-orbit coupled Bose gases“. Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/127720.
Der volle Inhalt der QuelleCataloged from the official PDF of thesis.
Includes bibliographical references (pages 147-151).
Quantum simulation is a very active and growing field. Various quantum systems can be used to emulate existing materials in an accurate and controllable way, as well as to generate new states of matter that have not been found in the real world but the existence of which does not contradict the fundamental laws of physics. Ultracold atoms form a perfect system to realize idealized models and study physical mechanisms that stand out clearly in them. Recent efforts have been made to simulate artificial gauge fields with ultracold atoms, including spin-dependent gauge fields, such as spin-orbit coupling. Motivated by this goal our lab explored several approaches to generate a one-dimensional spinorbit coupling interaction, which has a rich phase diagram and plays an important role for topological insulators, the quantum spin Hall effect and spintronics.
The first method we developed allowed us to detect a stripe phase by dressing Bose-Einstein condensates with an optical superlattice and Raman beams. The observed density modulation in the ground state meets the definition of the long-awaited supersolid state of matter. The second approach we took was to generate spin-orbit coupling without use of lasers. The method is based on the idea of periodic driving of the quantum system and dressing its evolution with fast micromotion, often refered to as Floquet engineering. Our experiment provided an insightful pedagogical example of what Floquet engineering is capable of. In the experiment we endowed a low energy radio-frequency photon with tunable momentum. When dressed with recoil momentum, the interaction of a radio-frequency photon with an atom occurred in a Doppler-sensitive way. We also demonstrated how to tune the momentum and flip its direction. In this thesis, I first describe the experiments done in the optical superlattice.
Then I discuss the behavior of periodically driven classical and quantum systems and provide detailed analysis of how a radio-frequency photon can be magnetically dressed with tunable momentum. The experiments we carried out demonstrated novel methods of generation for spin-dependent gauge fields and showed pedagogical examples and interpretations of evolution of periodically driven systems. The scheme of periodically driven atoms inspired a theoretical study of heating in Floquet systems.
by Boris Shteynas.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Physics
Morren, Sybil Huang. „Transonic aerodynamics of dense gases“. Thesis, Virginia Tech, 1990. http://hdl.handle.net/10919/42210.
Der volle Inhalt der QuelleMaster of Science
Watt, Richard Comrie 1952. „Corona discharge in anesthetic gases“. Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/291711.
Der volle Inhalt der QuelleZiemniczak, Aline. „Geração de novas correlações da soma-ponderada-de-gases-cinzas para espécies individuais de gases participantes“. reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/103827.
Der volle Inhalt der QuelleProblems involving radiation heat transfer in participating media are in general very complex to be solved due to the dependence of the radiative properties with the wavenumber. However, thermal radiation cannot be neglected, especially in combustion processes due to the high temperatures that are involved, making radiation the main heat transfer mode. Calculating the heat transfer by radiation involves absorption properties which varies with the temperature and wavelength, therefore the use of spectral models are required to obtain good results with low computational time. In this dissertation, the weighted-sum-of-gray-gases (WSGG) model was applied to resolve the radiation heat transfer in a one-dimensional finite system formed by two parallel plates with black walls, for different temperature profiles and concentrations of the participating species. New WSGG correlations were obtained for mixtures of vapor water and carbon dioxide, besides correlations for the individual chemical species of vapor water, carbon monoxide, carbon dioxide and methane. From the HITEMP 2010 database correlations were generated for three, four and five gray gases. From the correlations obtained for the weighted-sum-of-gray-gases (WSGG) model, their results are compared with the benchmark solution obtained by integrating line-by-line (LBL). For all the proposed cases, in general, it is possible to observe a satisfactory agreement between the results of the weighted-sum-of-gray-gases with the line-by-line method.
Kam, Chung-hau Brian. „A comparison & contrast of Hong Kong and overseas practices in landfill gas management“. Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19945589.
Der volle Inhalt der QuelleArthur, Lia Frieda. „Silicate sorbents for flue gas cleaning /“. Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
Der volle Inhalt der QuelleTrefzger, Christian. „Ultracold dipolar gases in optical lattices“. Doctoral thesis, Universitat Politècnica de Catalunya, 2010. http://hdl.handle.net/10803/6596.
Der volle Inhalt der QuelleEn 1989, M. Fisher et. al. predecían que el modelo de Bose-Hubbard homogéneo (BH) presenta la transición de fase cuántica Superfluid-Mott insulator (SF-MI). En 2002, la transición entre éstas dos fases fue observada experimentalmente por primera vez en el grupo de T. Esslinger e I. Bloch. La realización experimental de un BEC dipolar de cromo en el grupo de T. Pfau, y los progresos recientes en las técnicas de enfriamiento y atrapamiento de moléculas dipolares en los grupos de D. Jin e J. Ye, han abierto el camino hacia los gases cuánticos ultra-fríos dominados por la interacción dipolar. La evolución natural, y el reto de hoy en día por parte experimental, es de cargar BEC dipolares en retículos ópticos y estudiar los gases dipolares fuertemente correlacionados.
Antes de éste trabajo de doctorado, estudios sobre modelos de BH con interacciones extendidas a los primeros vecinos mostraron la evidencia de nuevas fases cuánticas, como el supersólido (SS) y la fase checkerboard (CB). Debido al carácter de largo alcance de la interacción dipolo-dipolo, que decae con la potencia cúbica inversa de la distancia, es necesario incluir más de un primer vecino para obtener una descripción fiel y cuantitativa de los sistemas dipolares. De hecho, al incluir más vecinos se permiten y se estabilizan aún más nuevas fases.
En esta tesis estudiamos modelos de BH con interacciones dipolares, investigando más allá del estado fundamental. Estudiamos un retículo bidimensional (2D) donde los dipolos están polarizados en dirección perpendicular al plano 2D, dando lugar a una interacción dipolar repulsiva e isotrópica. Utilizamos aproximaciones de campo-medio y un ansatz Gutzwiller, que son suficientemente correctos y adecuados para describir este sistema. Encontramos que los gases dipolares en 2D presentan una multitud de estados metaestables de tipo MI, que compiten con el estado fundamental, de modo parecido a sistemas desordenados. Estudiamos en detalle el destino de estos estados metaestables: como pueden ser preparados de manera controlada, como pueden ser detectados, cual es su tiempo de vida debido al tunnelling, y cual es su rol en los procesos de enfriamiento. Además, encontramos que el estado fundamental está caracterizado por estados MI de tipo checkerboard con coeficiente de ocupación n fraccionario (numero medio de partículas por sitio) que depende del cut-off utilizado en el radio de alcance de la interacción. Confirmamos esta predicción estudiando el mismo sistema con métodos Quantum Monte Carlo (worm algorithm). En este caso no utilizamos ningún cut-off en el radio de alcance de la interacción, y encontramos pruebas de una "Devil's staircase" en el estado fundamental, i.e. donde las fases MI aparecen en todos los n racionales del retículo subyacente. Encontramos además, regiones de los parámetros donde el estado fundamental es supersólido, obtenido drogando los sólidos con partículas o con agujeros.
En este trabajo, investigamos también como cambia la estructura precedente en 3D. Nos focalizamos en el retículo 3D más sencillo compuesto de dos planos 2D, en el cual los dipolos están polarizados perpendicularmente a los planos; la interacción dipolar es entonces repulsiva por partículas del mismo plano, mientras es atractiva por partículas en el mismo sitio de dos planos diferentes. En cambio suprimimos el tunnelling entre los planos, lo cual hace el sistema equivalente a una mezcla bosónica en un retículo 2D. Nuestros cálculos muestran que las partículas se juntan en parejas, y demostramos la existencia de la nueva fase cuántica Pair Super Solid (PSS).
Actualmente estamos estudiando un retículo 2D donde los dipolos están libres de apuntar en ambas direcciones perpendicularmente al plano, lo cual resulta en una interacción a primeros vecinos repulsiva (atractiva) por dipolos alineados (anti-alineados). Encontramos regiones de parámetros donde el estado fundamental es ferromagnético u anti-ferromagnético, y encontramos pruebas de la existencia de la fase cuántica Counterflow Super Solid (CSS).
Las nuestras predicciones tienen directas consecuencias experimentales, y esperamos que vengan pronto controladas en experimentos con gases dipolares atómicos y moleculares ultra-fríos.
This thesis is a theoretical work, in which we study the physics of ultra-cold dipolar bosonic gases in optical lattices. Such gases consist of bosonic atoms or molecules, cooled below the quantum degeneracy temperature, typically in the nK range. In such conditions, in a three-dimensional (3D) harmonic trap, weakly interacting bosons condense and form a Bose-Einstein Condensate (BEC). When a BEC is loaded into an optical lattice produced by standing waves of laser light, new kinds of physical phenomena occur.
These systems realize then Hubbard-type models and can be brought to a strongly correlated regime. In 1989, M. Fisher et. al. predicted that the homogeneous Bose-Hubbard model (BH) exhibits the Superfluid-Mott insulator (SF-MI) quantum phase transition. In 2002 the transition between these two phases were observed experimentally for the first time in the group of T. Esslinger and I. Bloch. The experimental realisation of a dipolar BEC of Chromium by the group of T. Pfau, and the recent progresses in trapping and cooling of dipolar molecules by the groups of D. Jin and J. Ye, have opened the path towards ultra-cold quantum gases with dominant dipole interactions. A natural evolution and present challenge, on the experimental side is then to load dipolar BECs into optical lattices and study strongly correlated ultracold dipolar lattice gases.
Before this PhD work, studies of BH models with interactions extended to nearest neighbours had pointed out that novel quantum phases, like supersolid (SS) and checkerboard phases (CB) are expected. Due to the long-range character of the dipole-dipole interaction, which decays as the inverse cubic power of the distance, it is necessary to include more than one nearest neighbour to have a faithful quantitative description of dipolar systems. In fact, longer-range interactions tend to allow for and stabilize more novel phases.
In this thesis we study BH models with dipolar interactions, going beyond the ground state search. We consider a two-dimensional (2D) lattice where the dipoles are polarized perpendicularly to the 2D plane, resulting in an isotropic repulsive interaction. We use the mean-field approximations and a Gutzwiller ansatz which are quite accurate and suitable to describe this system. We find that dipolar bosonic gas in 2D exhibits a multitude of insulating metastable states, often competing with the ground state, similarly as in a disordered system. We study in detail the fate of these metastable states: how can they be prepared on demand, how they can be detected, what is their lifetime due to tunnelling, and what is their role in various cooling schemes. Moreover, we find that the ground state is characterized by insulating checkerboard-like states with fractional filling factors v(average number of particles per site) that depend on the cut-off used for the interaction range. We confirm this prediction by studying the same system with Quantum Monte Carlo methods (the worm algorithm). In this case no cut-off is used, and we find evidence for a Devil's staircase in the ground state, i.e. where insulating phases appear at all rational of the underlying lattice. We also find regions of parameters where the ground state is a supersolid, obtained by doping the solids either with particles or vacancies.
In this work, we also investigate how the previous scenario changes in 3D. We focus on the simplest 3D lattice composed of two 2D layers in which the dipoles are polarized perpendicularly to the planes; the dipolar interaction is then repulsive for particles laying on the same plane, while it is attractive for particles at the same lattice site on different layers. Instead we consider inter-layer tunnelling to be suppressed, which makes the system analogous to a bosonic mixture in a 2D lattice. Our calculations show that particles pair into composites, and demonstrate the existence of the novel Pair Super Solid (PSS) quantum phase.
Currently we are studying a 2D lattice where the dipoles are free to point in both directions perpendicularly to the plane, which results in a nearest neighbour repulsive (attractive) interaction for aligned (antialigned) dipoles. We find regions of parameters where the ground state is ferromagnetic or antiferromagnetic, and find evidences for the existence of a Counterflow Super Solid (CSS) quantum phase.
Our predictions have direct experimental consequences, and we hope that they will be soon checked in experiments with ultracold dipolar atomic and molecular gases.
Beyerle, Urs. „Groundwater dynamics, paleoclimate and noble gases /“. [S.l.] : [s.n.], 1999. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13078.
Der volle Inhalt der QuellePunk, Matthias. „Many-particle physics with ultracold gases“. kostenfrei, 2010. https://mediatum2.ub.tum.de/node?id=956951.
Der volle Inhalt der QuellePedri, Paolo. „Dynamical behavior of ultracold atomic gases“. [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=975830414.
Der volle Inhalt der QuelleLeray, Gary. „PEGASES: Plasma Propulsion with Electronegative Gases“. Phd thesis, Ecole Polytechnique X, 2009. http://pastel.archives-ouvertes.fr/pastel-00005935.
Der volle Inhalt der QuellePrice, Hannah. „Topological phenomena in ultracold atomic gases“. Thesis, University of Cambridge, 2013. https://www.repository.cam.ac.uk/handle/1810/245059.
Der volle Inhalt der QuelleFernandes, Christine. „Termodinamica estendida de gases completamente ionizados“. reponame:Repositório Institucional da UFPR, 1996. http://hdl.handle.net/1884/48849.
Der volle Inhalt der QuelleDissertação(mestrado) - Universidade Federal do Parana
Resumo: Desenvolve-se uma teoria baseada na termodinâmica estendida para uma mistura binária constituída de íons e elétrons, sujeitos à ação de um campo magnético externo B, caracterizando um gás completamente ionizado. Os campos básicos desta teoria são as densidades de massa parcial, velocidade parcial, tensor pressão parcial e fluxo de calor parcial, perfazendo um total de vinte e seis campos escalares, cujas equações de balanço são obtidas a partir da equação cinética de Boltzmann. Do princípio da indiferença ao referencial e princípio da entropia, restringese a generalidade das equações constitutivas, conduzindo-nos a um conjunto de equações de campo. Deste conjunto de vinte e seis equações, seis delas serão utilizadas na determinação das densidades de massa dos íons e dos elétrons, da velocidade da mistura e de sua temperatura. Considerando os constituintes da mistura a uma mesma temperatura T, restam dezenove equações que fornecerão os deviantes do tensor pressão dos íons e dos elétrons da mistura, os fluxos de calor dos íons é dos elétrons além do vetor corrente elétrica, a partir da inversão de tensores de segunda e quarta ordem. As leis fenomenológicas de Ohm, Fourier e Navier - Stokes são obtidas, identificando- se os coeficientes de transporte da mistura: os tensores de viscosidade de cisalhamento, condutividade térmica e condutividade elétrica e os tensores dos efeitos cruzados, associados à difusão-termo e termo-difusão, verificando-se as relações de reciprocidade de Onsager para estes coeficientes de transporte. Através de uma escolha adequada de forças e fluxos termodinâmicos, os efeitos termoelétricos, termomagnéticos e galvanomagnéticos são também obtidos e analisados.
Abstract: A theory based on extended thermodynamics is developed for a binary mixture in the presence of magnetic field B , which characterizes a. completely ionized gas. The basic fields of this theory are the twenty-six scalars fields of partial mass densities, partial velocities, partial pressure tensors and partial heat fluxes. The balance equations are obtained from the Boltzmann kinetic equation. From the material frame indifference principle and the entropy principle, the generality of the constitutive equations is restricted, leading to a system of field equations. From this system of twenty-six equations, six of them are used to the determination of mass density of the ions, the mass densitiy of the electrons, the velocity of the mixture and its temperature. We have considered the constituints of the mixture at the same temperature T so that the remaining equations will provide the pressure deviators of the ions and of the electrons of the mixture, the heat fluxes of the ions, the heat fluxes of the electrons and finally the electric current vector, through inversions of secondorder and fourth-order tensors. The phenomenological equations of Ohm, Fourier and Navier-Stokes are obtained, and we have identified the transport coefficients of the mixture: the shear viscosity tensor, the thermal conductivity tensor, the electric conductivity tensor and the tensors of cross effects, wich are associated with diffusion-thermo and thermo-diffusion. We have verified the Onsager reciprocity relations for these coefficients. With an appropriate choice of thermodynamic forces and fluxes the thermoeletric, thermomagnetic and galvanomagnetic effects are also obtained and analised.
Franco, Kleber Serrão. „Filtração de gases a altas pressões“. Universidade Federal de São Carlos, 2012. https://repositorio.ufscar.br/handle/ufscar/4106.
Der volle Inhalt der QuelleThe filtration of gases is an important industrial operation with the primary aim of removing unwanted solid particles contained in a gas. The filtration of gases at high pressures is an operation widely used in natural gas industry with the aim of separating impurities called black powder, from rust inside pipelines along the transportation. These residues can cause wear on equipment such as, for example, rotor pump, obstruction of gauges and pressure decrease in product quality. Despite being an operation widely used, few studies exist in the area to study what the best type of filter. Therefore this study is very useful to improve the steps of transportation, measurement and purity of the final product. To simulate this process, we used the dry compressed air, injecting a phosphate rock as particulate matter. The filters were tested RAD cellulose and acrylic. The surface speed of filtration was kept constant at 0.05 m / s, throughout the filtering operation. The flow of compressed air used were 14 l / min to the total pressure 1 bar, 42 l / min at a total pressure of 3 bar and 86 l / min at a total pressure of 6 bar. Total load losses were 5, 10, 20 and 30 mbar. The results showed that, initially, the curves of head loss versus deposited mass showed the same growth trend. However, when forming a layer of cake from about 0.03 kg/m2, the filtrations higher pressures had lower pressure loss. This is because the larger pressure forming pies more porous and less resistant to air flow. At the end of the study it was also observed that the acrylic filter performed better compared to the cellulose RAD, due to its greater mass of accumulated dust and low pressure drop.
A filtração de gases é uma importante operação industrial com o principal intuito de remover as partículas sólidas indesejadas contidas em um determinado gás. A filtração de gases a altas pressões é uma operação muito utilizada na indústria de gás natural com o objetivo de separar as impurezas denominadas pó preto, provenientes da oxidação no interior de gasodutos ao longo do seu transporte. Estes resíduos podem causar desgaste de equipamentos como, por exemplo, rotor de bombas, obstrução de aparelhos de medição de pressão e diminuição da qualidade do produto. Apesar de ser uma operação muito utilizada, poucas pesquisas existem na área a fim de estudar qual o melhor tipo de filtro. Por isso este estudo é muito útil no sentido de melhorar as etapas de transporte, medição e pureza do produto final. Para simular este processo, foi utilizado o ar comprimido seco, injetando-se a rocha fosfática como material particulado. Os filtros testados foram de celulose RAD+ e acrílico. A velocidade superficial de filtração foi mantida constante em 0,05 m/s, durante toda a operação de filtração. As vazões do ar comprimido utilizadas foram de 14 l/min para a pressão total de 1 bar, 42 l/min para a pressão total de 3 bar e 86 l/min para a pressão total de 6 bar. As perdas de carga totais foram de 5, 10, 20 e 30 mbar. Os principais resultados mostraram que, inicialmente, as curvas de perda de carga versus massa depositada apresentaram igual tendência de crescimento. Porém, no momento que forma uma camada de torta a partir de aproximadamente 0,03 kg/m2, as filtrações de maiores pressões apresentaram menor perda de carga. Isso porque as maiores pressões formam tortas mais porosas e menos resistentes ao escoamento de ar. Ao final do estudo observou-se também que o filtro de acrílico obteve melhor desempenho comparado com o de celulose RAD+, por apresentar maior massa de pó acumulada e menor perda de carga.
Malevanets, Anatoly. „Statistical mechanics of hydrodynamic lattice gases“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ27690.pdf.
Der volle Inhalt der QuelleSteinbacher, John James. „Positron annihilation in simple condensed gases“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0001/NQ35980.pdf.
Der volle Inhalt der QuelleGunawardena, Rohith. „Global distribution of organo-bromine gases /“. Full text open access at:, 1989. http://content.ohsu.edu/u?/etd,245.
Der volle Inhalt der QuelleAlam, M. „Computation of flow of rotating gases“. Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239352.
Der volle Inhalt der QuelleMurphy, A. K. „Satellite measurements of atmospheric trace gases“. Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371568.
Der volle Inhalt der QuelleBaker, S. J. „Piezoelectric crystal detection of noxious gases“. Thesis, University of Hull, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380775.
Der volle Inhalt der QuelleJackman, L. A. „Sprinkler spray interactions with fire gases“. Thesis, London South Bank University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.482025.
Der volle Inhalt der QuelleNunnenkamp, Andreas. „Strong correlations in ultracold atomic gases“. Thesis, University of Oxford, 2008. http://ora.ox.ac.uk/objects/uuid:6e09e9d3-f5cd-4580-a667-6599203162e2.
Der volle Inhalt der QuelleDouglas, James Stewart. „Light scattering from ultracold atomic gases“. Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:0aa4ede3-8b6e-45d4-a112-a2d18271307c.
Der volle Inhalt der QuelleHeaney, Libby. „Entanglement of non-interacting Bose gases“. Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491808.
Der volle Inhalt der QuelleNewell, Catherine A. „INELASTIC COLLISIONS IN COLD DIPOLAR GASES“. UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_diss/30.
Der volle Inhalt der QuelleIvings, Matthew J. „Wave propagation through gases and liquids“. Thesis, Manchester Metropolitan University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389611.
Der volle Inhalt der QuelleBlackwood, Jennifer Elizabeth. „Positronium scattering by the noble gases“. Thesis, Queen's University Belfast, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343099.
Der volle Inhalt der Quelle