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Okambawa, Richard. "Étude expérimentale des interactions moléculaires gaz-gaz et gaz-adsorbant à partir des coefficients du viriel thermophysiques et des coefficients du viriel de la constante diélectrique /". Thèse, Trois-Rivières : Université du Québec à Trois-Rivières, 1999. http://www.uqtr.ca/biblio/notice/resume/03-2208187R.html.
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Thèse (Ph.D.) - Université du Québec à Trois-Rivières - INRS, 1999.En-tête de titre : Université du Québec. Institut national de la recherche scientifique (Énergie et matériaux). "Cette thèse a été réalisée à l'Université du Québec à Trois-Rivières... dans le cadre du programme du doctorat en sciences de l'énergie et des matériaux de l'Institut national de recherche scientifique-Énergie et matériaux extensionné à l'Université du Québec à Trois-Rivières." CaQTU CaQTU Comprend des références bibliogr.
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Okambawa, Richard. "Étude expérimentale des interactions moléculaires gaz-gaz et gaz-adsorbant à partir des coefficients du viriel thermophysiques et des coefficients du viriel de la constante diélectrique". Thèse, Université du Québec à Trois-Rivières, 1999. http://depot-e.uqtr.ca/6713/1/000664973.pdf.
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Candau, Didier. "Caractérisation de polymères absorbant la lumière ultraviolette : étude des relations entre la conformation en solution et l'absorbance". Paris 12, 1989. http://www.theses.fr/1989PA120037.
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Etude d'un polymere absorbant dans l'ultraviolet a 297 nm. L'homopolymere presente une hypochromicite par rapport au chromophore. La synthese de copolymeres permet de reduire cette hypochromicite par l'espacement des chromophores. Pour une meme structure, l'homopolymere, l'etude de la conformation en solution en relation avec l'absorbance montre que l'expansion de la chaine obtenue dans des melanges de solvant-non solvant permet de reduire l'hypochromicite du polymere. L'etude de l'influence du poids moleculaire montre qu'il ne peut y avoir concordance entre les interactions intramoleculaires et intermoleculaires, et que les premieres diminuent plus rapidement que les secondes quand la masse diminue dans le thf. L'hypochromicite est donc diminuee quand la masse diminue; ceci est caracterise par un deuxieme coefficient du viriel et un coefficient d'expansion moleculaire qui augmentent quand la masse diminue
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Costenaro, Lionel. "Interactions faibles protéine – protéine en solution : La malate déshydrogénase halophile". Phd thesis, Université Joseph Fourier (Grenoble), 2001. http://tel.archives-ouvertes.fr/tel-00007698.
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La cellule est un milieu très concentré où les interactions entre macromolécules, même faibles, jouent un grand rôle dans leur solubilité et dans l'assemblage des complexes labiles assurant les fonctions biologiques. Les interactions faibles entre protéines déterminant la non-idéalité de leurs solutions vont aussi gouverner leur cristallisation.Dans quelle mesure les interactions protéine – solvant influencent-elles les interactions protéine – protéine ? Nous avons mis en relation ces deux types d'interactions pour la malate déshydrogénase (Hm MalDH) de Haloarcula marismortui, protéine halophile très acide qui a des solvatations variées et très riches en eau et en sel.
Nous avons développé une nouvelle méthode de détermination du second coefficient du viriel A2 par la modélisation des profils de vitesse de sédimentation en ultracentrifugation analytique, qui permet l'étude de solvants complexes.
Les interactions protéine – protéine de la Hm MalDH en divers sels ont été caractérisées par diffusion de neutrons ou de rayons X aux petits angles. Les A2 et les facteurs de structure en solution ont été modélisés par des potentiels d'interaction de type DLVO. Les interactions répulsives sont principalement dues au terme de volume exclu et dans une moindre mesure au terme électrostatique. Les interactions attractives sont qualitativement corrélées à des valeurs positives ou négatives des paramètres d'interaction préférentielle avec le sel. Ces résultats permettent d'expliquer l'adaptation moléculaire des protéines halophiles qui doivent ainsi avoir une solvatation riche en sel pour rester soluble à haut sel.
La cristallisation par dilution de la Hm MalDH dans des mélanges sel – MPD (méthyl-2-pentanediol-2,4) résulte d'une lente évolution des interactions protéine – protéine, de répulsives à modérément attractives. Le MPD modifie les interactions protéine – protéine en divers sels en ajoutant une attraction qui est liée à la répulsion du MPD par les charges de la protéine.
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Barret, Laurie-Anne. "Influence des tensioactifs dans la cristallisation du complexe photosynthétique RC-LH1-pufX de Rhodobacter blasticus". Phd thesis, Université d'Avignon, 2013. http://tel.archives-ouvertes.fr/tel-01017895.
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Ce projet vise à étudier, par une approche pluridisciplinaire, l'influence des la cristallisation des protéines membranaires (PM) en prenant pour protéine modèle le complexe photosynthétique RC-LH1-pufX de Rhodobacter blasticus. Des cristaux de ce complexe avaient été obtenus en présence de dodécyl-!-maltoside (DDM) et avaient diffractés à 8 Å de résolution. L'objectif final est de pouvoir améliorer, de façon rationnelle, la qualité des cristaux du complexe RC-LH1-pufX grâce à une meilleure compréhension des mécanismes mis en jeu. Dans un premier temps, trois tensioactifs dérivés du DDM ont été conçus et synthétisés. L'intérêt est d'augmenter la rigidité et le caractère lipophobe des parties hydrophobes des tensioactifs par rapport au DDM, pour les rendre moins déstabilisants envers la protéine: soit par l'incorporation d'un groupement bicyclohexyle (PCC-maltoside), soit par l'ajout d'un segment fluoré de longueur modulable (F4H5- et F2H9-maltoside). Nous avons inclus également le F8TAC, tensioactif fluoré utilisé depuis une vingtaine d'années pour le maintien en solution des PM, et les "tripodes", amphiphiles faciaux dont la géométrie particulière n'avaient jamais été testée. Nous avons ensuite réalisé la caractérisation physico-chimique, en solution, de ces tensioactifs et du DDM en terme de CMC (concentration micellaire critique), nombre d'agrégation, taille (par diffusion de la lumière dynamique, DLS), facteur de forme (par diffusion des rayons X aux petits angles, SAXS) et facteur de structure (par mesure du second coefficient du viriel, indicateur du potentiel des tensioactifs à initier la cristallisation)afin de déterminer les caractéristiques importantes au maintien en solution et à la cristallisation des PM. Le PCC-malt présentant le même comportement que le DDM,nous l'avons sélectionné pour réaliser une étude en présence de la protéine.Après avoir mis au point une méthode de dosage des tensioactifs par HPTLC (HighPerformance Thin Layer Chromatography) et identifier les lipides présents dans les de Rhodobacter blasticus, nous avons pu quantifier les quantités de lipides et de tensioactifs associés à la protéine en présence de DDM et de PCC-malt.Enfin, dans une dernière partie, nous avons réalisé des essais de cristallisation du complexe RC-LH1-pufX en présence des tensioactifs sélectionnés pour faire le lien entre les conditions de cristallisation et l'étude physico-chimique des micelles en solution.
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Shvets, Alexey. "Theory of colloidal stabilization by unattached polymers". Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAE025/document.
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Les dispersions colloïdales ont beaucoup d’applications technologiques importantes. A cause du mouvement brownien, les particules ont des collisions fréquentes entre elles. Les forces d’attraction de van der Waals,dérivant de potentiels à longue portés, conduisent à l’agrégation et à la précipitation des particules. Plusieurs méthodes ont été proposées pour diminuer ou contrebalancer l’effet d’attraction de van der Waals et augmenter la stabilité colloïdale. Par exemple, le choix du solvant possédant l’indice de réfraction le plus proche possible de celui des particules peut diminuer les forces de van der Waals. D'autres facteurs influencent la stabilité comme les interactions électrostatiques et les interactions spécifiques liées aux chaînes de polymères. Dans le cas des polymères, les chaînes peuvent être greffées à la surface des particules ou être dissoutes dans le solvant (chaînes libres). Dans ce travail de thèse, nous avons étudié l’effet de la stabilisation par déplétion dans le cas des chaînes de polymères libres (FPI, "free polymer induced interaction"). Des modèles théoriques précédents portent un caractère trop simplifié et utilisent des approximations sans vérification. De plus, l’influence des paramètres de la solution, c’est-à-dire, de la structure de polymères et de son interaction avec la surface de particule, n’a pas été étudiée.Les chaînes polymères libres ont été modélisées comme des marches aléatoires dans un champ moléculaire auto-cohérent qui satisfait à l'équation intégro-différentielle de diffusion. Pour le domaine moléculaire, nous avons utilisé un potentiel chimique qui, pour la solution de polymère semi-dilué, peut être représenté comme une expansion du viriel où nous n’avons pris en considération que les deuxième et troisième coefficients du viriel de la solution de polymère. En variant des paramètres tels que la rigidité du polymère, la longueur du polymère, la concentration en polymère et le régime du solvant (comme le solvant thêta), que ce soit pour une surface colloïdale purement répulsive, pour une surface adsorbée ou pour la surface d'une couche de polymère greffé, nous avons été en mesure d'améliorer la barrière répulsive due aux polymères libres entre les particules et donc nous avons trouvé des conditions de la stabilisation cinétique du systèmeStable colloidal dispersions with evenly distributed particles are important for many technological applications. Due to Brownian motion colloidal particles have constant collisions with each other which often lead to their aggregation driven by the long range van der Waals attraction. As a result the colloidal systems often tend to precipitate. A number of methods have been devised to minimize the effect of long-range van der Waals attraction between colloidal particles or to override the influence of the attraction in order to provide the colloidal stability.In the PhD thesis we investigated the colloidal stabilization in solutions of free polymers which is commonly referred to as depletion stabilization. Previous theoretical studies of free-polymer induced (FPI) stabilization were based on oversimplified models involving uncontrolled approximations. Even the most basic features of the depletion stabilization phenomenon were unknown. It was unclear how the PI repulsion depends on the solution parameters, polymer structure and monomer/surface interactions.The free polymer chains were modeled as random walks in a self-consistent molecular field that satisfied to diffusion-like integro-differential equation. As the molecular field we used the chemical potential that for semi-dilute polymer solution can be represented as a virial expansion where we took into account only second and third virial coefficients of the polymer solution. Varying the parameters like polymer stiffness, polymer length, polymer concentration and solvent regime (like theta solvent) whether it is for purely repulsive colloidal surface, adsorbed surface or surface with grafted polymer layer we were able to enhance the repulsive barrier due to the free polymers between the particles and therefore found conditions for kinetic stabilization of the system
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Soetens, Jean-Christophe. "Développement d'un programme de dynamique moléculaire incluant des modèles électrostatiques élaborés : application à l'étude de fluides polarisables et de solutions ioniques". Nancy 1, 1996. http://www.theses.fr/1996NAN10241.
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Le travail présenté dans cette thèse s'inscrit dans le cadre des simulations de dynamique moléculaire appliquées à l'étude de fluides polarisables et de solutions ioniques. Une attention particulière est portée à la description explicite de la polarisabilité dans les modèles d'interaction intermoléculaire. Nous présentons notamment des modèles électrostatiques comportant des multipôles et des polarisabilités distribués. Ce travail a nécessité l'écriture d'un nouveau code de dynamique moléculaire permettant de traiter les liquides purs et les solutions à l'aide de modèles électrostatiques de complexités très variables. Le premier chapitre décrit les principes de base des techniques de simulation ainsi qu'une description générale du programme dont une présentation plus technique est donnée en annexe. Le second chapitre est consacre à l'étude des propriétés de l'eau en phases gazeuse et liquide. Dans le troisième chapitre, un calcul de potentiel de force moyenne caractérisant l'approche de deux ions guanidinium dans l'eau est présenté. Le quatrième et dernier chapitre décrit les résultats de l'étude des propriétés de solutions ioniques d'intérêt électrochimique.
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Quigley, Amanda Leila. "Protein aggregation behaviour and the second virial coefficient". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/17935.
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One key barrier to the timely and efficient production of biopharmaceuticals is that they are prone to both chemical and physical instability including aggregation. Protein-protein molecular interactions are known to be a factor in protein solution aggregation behaviour; however their practical and elementary importance has not been fully established. The osmotic second virial coefficient (B22) is a fundamental physiochemical property that describes the molecular interactions between proteins in solution which could result in aggregation. This experimental study reports on the B22 of five different proteins (lysozyme, lactoferrin, catalase, concanavalin A and anti-TNFα dAb) using Self-Interaction Chromatography (SIC) over a wide range of solution conditions including the effects of pH, salt concentration, salt type as well as excipient stabilisers. It was established that current practise for SIC peak analysis was inadequate, and an improved method of SIC peak analysis was deployed which provided improved B22 data quality and robustness. Protein aggregation performance was evaluated under identical solution conditions to those used for the B22 determinations using a simple Dynamic Light Scattering based measurement of initial solution aggregate size. This data shows a direct and strong correlation between B22 values and protein aggregation performance for all systems studied here. Specifically, proteins solution systems with B22 values of ~ 1 x 10-4 mL mol g-2 or less, regardless of solution composition, all exhibited aggregation behaviour. This thesis establishes the decisive importance of B22 as a predictor of aggregation performance. Preliminary validation data is presented for a method which allows for B22 estimation from osmotic cross virial coefficients (B23), removing the need for immobilisation of the protein of interest and therefore allowing rapid B22 screening.
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Ma, Yingfang. "Long-range Interactions and Second Virial Coefficients of Biomolecular Materials". Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1416915622.
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Knutsen, Jeffrey Steven. "Membrane bioseparations: Cellulase recovery, particle deposition, and second osmotic virial coefficients". Diss., Connect to online resource, 2005. http://wwwlib.umi.com/dissertations/fullcit/3165833.
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Verma, Kusum S. "The osmotic second virial coefficient as a predictor of protein stability". Master's thesis, Mississippi State : Mississippi State University, 2006. http://sun.library.msstate.edu/ETD-db/ETD-browse/browse.
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White, M. P. "Direct measurement of the dielectric virial coefficients of helium from 3 to 17.67 K". Thesis, University of Bristol, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281845.
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Subramanian, Ramachandran. "Quantum virial coefficients via path integral Monte Carlo| Theory and development of novel algorithms". Thesis, State University of New York at Buffalo, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10127734.
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Virial coefficients are unique thermodynamic properties of a system owing to their link be- tween interactions at the molecular level to macroscopic quantities such as the pressure. In this work, we take advantage of this feature and compute virial coefficients of a variety of systems by performing simulation studies. The nature and quality of the interaction potential used in such studies highly affects the quality of the resulting virial coefficients. Therefore, we have employed ab initio based interaction potentials that are state-of-the-art and have been developed using high quality quantum chemistry calculations. Naturally, the complexity of such simulations is a strong motivator for the development of algorithms that are highly efficient and yield precise results. In this regard, we have developed two efficient and novel algorithms for use in Path Integral Monte Carlo (PIMC), a method used to incorporate nuclear quantum effects in virial coefficient calculations for diatomic molecules. We have successfully applied these algorithms to compute virial coefficients including quantum effects or, in short, quantum virial coefficients, for H2, N2 and O2 sys- tems. In addition to applying these algorithms to study diatomic molecules, we have also investigated other algorithms like PIMC using semi-classical beads and compared them to conventional PIMC, for He as well as N2 systems. Finally, we have also evaluated virial coefficients including quantum corrections, or, in short, semi-classical virial coefficients for a latest ab initio potential of water.
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Parupudi, Arun Kumar. "Demonstration of scale-down dynamic light scattering and determination of osmotic second virial coefficients for proteins". Master's thesis, Mississippi State : Mississippi State University, 2007. http://sun.library.msstate.edu/ETD-db/theses/available/etd-11092007-112135/.
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HASMONAY, CHAPUT DANIELE, i Monique Dupeyrat. "Etude theorique et experimentale du second coefficient du viriel de couches monomoleculaires d'acides carboxyliques solubles ou insolubles dans l'eau". Paris 6, 1990. http://www.theses.fr/1990PA066165.
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Les couches monomoleculaires diluees d'acides carboxyliques a l'interface air-eau sont etudiees sur le plan theorique et sur le plan experimental par l'analyse du second coefficient du viriel b(t) relatif a la tension interfaciale. L'expression theorique de b(t) est obtenue en utilisant la theorie de mac millan et mayer. L'interaction solute-solvant intervient explicitement dans l'expression de b(t) et privilegie certaines configurations du solute. Entre deux molecules de solute le potentiel d'interaction est remplace par le potentiel de la force moyenne qui exprime leur interaction en presence du solvant. Ce potentiel est considere comme le potentiel des molecules dans le vide auquel s'ajoute une correction liee au solvant, qui represente des effets a trois corps solte-solvant-solute. Pour les groupes polaires immerges, la correction est definie a partir de considerations sur les potentiels images. Pour les chaines situees dans l'air elle est determinee d'apres le modele de sinanuglu et pitzer. La comparaison entre les resultats theoriques et experimentaux correspondant a differents modeles nous permet de proposer une structure commune aux deux types de couches soluble ou insoluble etudiees
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Rambaks, Andris, Filipp Kratschun, Carsten Flake, Maren Messirek, Katharina Schmitz i Hubertus Murrenhoff. "Computational approach to the experimental determination of diffusion coefficients for oxygen and nitrogen in hydraulic fluids using the pressure-decay method". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71099.
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In the presented paper, the applicability of pressure-decay methods to determine the diffusivities of gases in hydraulic fluids is analysed. First, the method is described in detail and compared to other measurement methods. Secondly, the thermodynamics and the mass transfer process of the system are studied. This results in four different thermodynamic models of the gaseous phase in combination with two diffusion models. Thirdly, the influence of the models on the pressure-decay method is evaluated computationally by examining the diffusion process of air in water as all system parameters are available from literature. It is shown that ordinary pressure-decay methods are not applicable to gas mixtures like air and therefore a new method for calculating the diffusivities is suggested.
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Gandhi, Shikha. "Investigation Of The Effect Of Low Molecular Weight Peg On Lysozyme Interactions In Solution Using Composition Gradient Static Light Scattering". The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1204599050.
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Bartling, Karsten. "Apoferritin Crystallization in relation to Eye Cataract". Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14111.
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Protein crystallization is significant in both biotechnology and biomedical applications. In biotechnology, crystallization is essential for determining the structure of both native and synthesized therapeutically important proteins. It can also be used as a final purification step and as a stable form for protein storage. With regard to biomedical systems, protein crystallization appears to be involved in the development and manifestation of certain human diseases. In particular, there exists evidence that L-rich ferritin crystals are involved in Hereditary Hyperferritinemia Cataract Syndrome (HHCS).
In the current research a microbatch crystallization apparatus has been introduced that enables (1) multiple batch crystallization experiments at various temperatures and solution conditions in parallel and (2) quantitative monitoring of crystal growth without disturbing the progress of an experiment for observation. The primary application of the apparatus is, but not limited to, screening of protein crystallization conditions, although the system can also be used for other macromolecular and small-molecule crystallization experiments.
Multiwell microbatch experiments demonstrated the dependence of apoferritin crystal growth kinetics and final crystal size on temperature and cadmium concentration. Although the solubility of apoferritin might be independent of temperature, the results of this study show that the crystal growth kinetics are affected by temperature, profoundly under some conditions.
For apoferritin under near physiological conditions the solution thermodynamics in the form of the second virial coefficient have proofed to be a valuable predictor for the crystallization outcome. Furthermore, the significance of the elevated level of some divalent cations in cataractous lenses has been studied both in dilute solutions and under crystallization conditions and cadmium seems to be sole menace in apoferritin condensation.
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Vivares, Denis. "Interactions en solution et cristallisation de l'urate oxydase". Paris 6, 2003. http://www.theses.fr/2003PA066336.
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Guerrero, André de Oliveira. "Aplicação da termodinâmica dos meios homogêneos ao estudo de estados metaestáveis e instáveis". [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249917.
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Orientador: Adalberto Bono Maurizio Sacci BassiDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: A equação original de van der Waals é alterada de modo a aprimorar sua aderência a dados experimentais para o Argônio, desde as baixas densidades dos estados gasosos até as altas densidades dos líquidos e dos vidros. Isto permite a obtenção de uma curva spinodal (fronteira termodinâmica entre os estados não acessíveis pela matéria e os estados possíveis, estáveis ou não) mais precisa do que a atualmente disponível, além de fornecer subsídios para estudos de líquidos e gases não estáveis. A pressão repulsiva original é substituída pela pressão de um sistema de esferas rígidas, enquanto que a pressão atrativa original é substituída pela pressão de um campo médio isotrópico descrito por três parâmetros. A realização destas alterações propicia a discussão de diversos aspectos da interpretação física da equação de van der Waals. Como os estados considerados são homogêneos, mas não necessariamente estados de equilíbrio, a temporal termodinâmica dos meios homogêneos é uma teoria adequada à descrição dos estados representados pela equação alterada.
Abstract: The original van der Waals equation is altered to improve its quantitative description of argon experimental values, including those of low density gaseous states and high density liquids and glasses. A spinodal curve is obtained (the limit between thermodynamically forbidden and permitted states of matter, either stable or unstable) that is more precise than the one actually available and reveals more information for studying unstable gases and liquids. The pressure of a rigid spheres system substitutes the original repulsive pressure, while the pressure of an isotropic mean field defined by three parameters substitutes the original attractive pressure. Implementing these substitutions provokes the discussion of several aspects, related to the physical meaning of van der Waals equation. Since only homogeneous states are considered, although they are not necessarily equilibrium states, time dependent thermodynamics of homogeneous media is an adequate theory to describe the states represented by the altered equation.
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Físico-Química
Mestre em Química
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Florindo, Caio César Ferreira 1988. "Estudo de estados estáveis e não estáveis através da termodinâmica dos processos homogêneos em meios contínuos". [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249873.
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Orientador: Adalberto Bono Maurizio Sacchi BassiDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: O presente trabalho tem três metas principais: (1) usar as transformações de Levin para estimar coeficientes viriais e avaliar a qualidade das estimativas; (2) inserir adaptações, coerentes com as transformações de Levin, na equação original de van der Waals, de modo a aprimorar sua capacidade de se aproximar de dados experimentais para estados estáveis; (3) extrapolar a equação adaptada, para possibilitar o estudo de estados não estáveis. Os resultados indicam que as transformações de Levin podem ser usadas como uma forma aproximada de representar a série virial, porque os coeficientes viriais de alta ordem, por elas estimados, estão em boa concordância com os valores obtidos na literatura. A utilização das representações de Levin para a adaptação do termo repulsivo da equação de van der Waals, juntamente com uma alteração proposta para o termo atrativo, produz isotermas subcríticas e supercríticas em boa concordância com os dados experimentais e proporciona aprimoramento da previsão do comportamento do sistema. As novas equações podem ser aplicadas tanto em densidades referentes à região de fase gasosa, como de fase líquida. Devido às boas previsões de resultados produzidas pelas equações desenvolvidas neste trabalho, são obtidas curvas spinodais com um nível de exatidão muito superior àquele encontrado na literatura. Portanto, o presente trabalho descreve equações aprimoradas que representam estados estáveis tão bem que podem ser extrapoladas para estados não estáveis
Abstract: This work aims at three main goals: (1) to use Levin's sequence transformations for estimating virial coefficients, and to assess the quality of the estimates; (2) to insert in the van der Waals equation some modifications consistent with the Levin's sequence transformations, enhancing its ability to approximate experimental data for stable states; (3) to extrapolate the modified equation for studying unstable states. The results indicate that the Levin's sequence transformations can be used as an approximate way to represent the virial series, because the high order estimated virial coefficients are in good agreement with values reported in literature. The use of the Levin's sequence transformations for modifying the repulsive term of van der Waals equation, together with a proposed attractive term improvement, yields subcritical and supercritical isotherms in good agreement with experimental data and provides better predictions of the behavior of the system. The new equations can be applied both at densities corresponding to gaseous and liquid phases. According to the good predictions of experimental results produced by the equations developed in this work, spinodal curves which are much more accurate than those found in literature are obtained. Therefore, this work describes improved equations that represent stable states well enough to accept extrapolation to unstable states
Mestrado
Físico-Química
Mestre em Química
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Ould-Kaddour, Latifa. "Etude par diffusion de la lumiere des systemes ternaires : polymere-polymere-solvant". Strasbourg 1, 1988. http://www.theses.fr/1988STR13006.
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Etude experimentale de plusieurs systemes ternaires, comportant deux polymeres differents en solution par diffusion de la lumiere. L'analyse de l'intensite diffusee a vecteur d'onde nul a permis de caracteriser les proprietes thermodynamiques et plus particulierement le parametre d'interaction entre les deux polymeres
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Cuevas, Sergio Alejandro Poveda. "Coarse-grained modeling with constant pH of the protein complexation phenomena". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/95/95131/tde-09062017-123617/.
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Theoretical studies of the molecular mechanisms responsible for the formation and stability of protein complexes have gained importance due to their practical applications in the understanding of the molecular basis of several diseases, in protein engineering and biotechnology. The objective of this project is to critically analyze and refine a coarse-grained force field for protein-protein interactions based on experimental thermodynamic properties and to apply it to cancer-related S100A4 protein system. Our ultimate goal is to generate knowledge for a better understanding of the physical mechanisms responsible for the association of particular proteins in different environments. We studied the role of short and long-range interactions on the complexation of homo-associations. Furthermore, we analyzed the influence of the pH and its correlation with the charge regulation mechanism. We analyzed and refined the adjustable Lennard-Jones parameter for a mesoscopic model based on experimental second virial data for lysozyme, chymotrypsinogen, and ribonuclease A via Monte Carlo simulations. From of that, the S100A3 protein was used to test the new calibrated parameters. Finally, we evaluated the dimerization process of S100A4 proteins, observing the role of physical-chemistry variables involved in the thermodynamical stability of different oligomers.Estudos teóricos dos mecanismos moleculares responsáveis pela formação e estabilidade dos complexos de proteínas vêm ganhando importância devido às suas aplicações práticas no entendimento da base molecular de várias doenças, em engenharia de proteínas e biotecnologia. O objetivo deste projeto é analisar criticamente e aperfeiçoar um campo de força de granulidade grossa para interação proteína-proteína com base em propriedades termodinâmicas experimentais e aplicá-lo ao sistema proteico S100A4 relacionado com o câncer. Nosso objetivo final é gerar conhecimento para uma melhor compreensão dos mecanismos físicos responsáveis pelas associações de proteínas particulares em diferentes ambientes. Estudamos o papel das interações de curto e longo alcance na complexação de homo-associações. Além disso, analisamos a influência do pH e sua correlação com o mecanismo de regulação de cargas. Por meio de simulações Monte Carlo, analisamos e refinamos o parametro ajustável de Lennard-Jones para um modelo mesoscópico, usando dados experimentais do segundo virial para a lisozima, o quimotripsinogênio e a ribonuclease A. A partir disso, a proteína S100A3 foi usada para testar os novos parâmetros calibrados. Finalmente, foi avaliado o processo de dimerização das proteínas S100A4, observando o papel de algumas variáveis físico-químicas envolvidas na estabilidade termondinâmica de diferentes oligómeros.
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Nwanosike, Quinta M. "Effect of divalent cations and solubilizers in apoferritin and gamma D-crystallin solutions nucleation, crystallization and light scattering studies /". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31736.
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Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2010.Committee Chair: Ronald Rousseau; Committee Co-Chair: Athanassios Sambanis; Committee Member: Amyn Teja; Committee Member: Athanasios Nenes; Committee Member: Ingeborg Schmidt-Krey. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Calixto, Tulio Marcus Ribeiro. "Análises de propriedades eletrostáticas e estruturais de complexos de proteínas para o desenvolvimento de preditores de complexação em larga escala". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/60/60136/tde-17112010-093652/.
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Estudos teóricos dos mecanismos moleculares responsáveis pela formação e estabilidade de complexos moleculares vêm ganhando relevância pelas possibilidades práticas que oferecem, por exemplo, na compreensão de diversas doenças e no desenho racional de fármacos. Neste projeto, nossa ênfase está no estudo de complexos de proteínas, extraídos do banco de dados de proteínas (PDB), onde desenvolvemos ferramentas computacionais as quais permitem efetuar análises em duas direções: 1) efetuar previsões básicas, através do emprego de propriedades eletrostáticas de proteínas, em diferentes condições e níveis preditivos e 2) realização de um conjunto de análises estatísticas, como freqüência de contato, em busca de preditores de complexos de proteínas e identificar padrões de interação entre seus aminoácidos em função da distância de separação. Com base nos resultados obtidos por ambos os estudos, objetivamos quantificar as forças físicas envolvidas na formação dos complexos protéicos. O foco do projeto, a longo prazo, é prever o fenômeno da complexação através da fusão dessas duas linhas de estudos: preditor básico de complexos protéicos e análise do potencial estatístico entre os aminoácidos que formam o complexo. O presente projeto é concluído com a construção de portais web que disponibilizarão os resultados obtidos por nossos trabalhos bem como a possibilidade de qualquer usuário, efetuar consultas por propriedades de proteínas e/ou grupo de proteínas.Theoretical studies of the molecular mechanisms responsible for the formation and stability of molecular complexes are gaining relevance for the practical possibilities that they offer, for example, in the understanding of diverse diseases and rational drug design. In this project, our emphasis is on the study of protein complexes, extracted from protein data bank (PDB). We have developed computational tools which allow to perform analyses in two directions: 1) to make basic complexation forecasts, through the use of electrostatics properties of proteins, in different conditions and predictive levels, and 2) to carry out a set of statistical analyses, as contacts frequency, in order to build up predictor of protein complexes and to identify patters of interactions between the amino acids as a function of their separation distance. Based on the results obtained on both studies, we aim quantify the physical forces involved in the formation of protein complexes. The focus of the project, in the long run, is to foresee the phenomenon of the protein complexes through the fusing of these two study lines: a coarse-grained predictor of protein complexes and analysis of the statistical potentials between the amino acids that form the complex. The present project is concluded with the construction of web services where we make available the results obtained on our works. This server also has the possibility to be used by any computer user, that wishes to perform search on protein and/or protein group properties
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Lapp, Alain. "Synthese, conformation et interactions de molecules lineaires et ramifiees de polydimethylsiloxane : mise en evidence de lois d'universalite". Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13108.
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Synthese du polydimethylsiloxane etudie et etude de l'hydrosilation se produisant au cours de la reticulation en solution semidiluee, relation entre la longueur de correlation et la concentration. Interactions a trois corps dans le styrene, solvant theta du pdmsi
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Huang, Yu-chiang, i 黃俞強. "Second Virial Coefficient Measurements by Isothermal". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/07706843453535864591.
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碩士國立中央大學
化學工程與材料工程學系
102
Understanding the proteins self-interactions in solution system has great potential value due to its relevance in several research and applications fields, such as bio-separation、protein conformational disease and biopharmaceutical development. Particularly in several stages of biopharmaceutical process, protein aggregation has been observed frequently. Therefore, a priori prediction of protein pair potentials will provide crucial information for analyzing or screening suitable solution conditions. The second virial coefficient (B22), a thermodynamic parameter that characterizes the non-ideal solution behavior arising from two body solute-solute interactions, is a potential predictive tool. Determinations of B22 proteins have been extensively and mostly done by self-interaction chromatography (SIC). In this study, a novel platform, isothermal titration calorimetry (ITC), is established to describe the B22 of proteins with polarized surface charges distribution in aqueous solutions by means of measure the dilution enthalpy of protein solution. With the aim, B22 of Myoglobin and Ribonuclease A are measured by ITC in different solution conditions(pH、salt concentration、salt type), and compared to results obtained from self-interaction chromatography (SIC). Furthermore, size-exclusion chromatography and crystallization results offer the efficient way to let us verify whether or not proteins are stable in solution. Detailed discussion as following: in the research of Myoglobin, the protein-protein interactions are repulsive with increasing salt concentration in ITC and SIC system. Moreover, different kinds of salt in solution affect the proteins’ behavior, which are consistent with Hofmeister Series. On the other hand, the research of Ribonuclease A shows that protein-protein interactions change from repulsive to attractive with increasing NaCl concentration in ITC system. Furthermore, comparing the experimental results from ITC and SIC, we discover the adverse results as the pH value of solution is close to the pI value of protein and at lower salt concentration. Under this circumstance, the charge distribution on protein surface is anisotropic. Meanwhile, B22 measurement in SIC system is not convincing because the immobilized proteins can’t move freely. On the contrary, we can describe protein behaviors in solution precisely by ITC measurement, because of the degrees of freedom of protein are not restricted. Additionally, at the aforementioned conditions, the less aggregation of Ribonuclease A is detected from the size-exclusion chromatography measurements. Consequently, we successfully establish a platform to measure B22 of proteins with isotropic or anisotropic surface charges distribution in ITC system.
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林薛智. "Generalized Equations for Second Virial Coefficient of Non-polar Fluids and Cross Second Virial Coefficient of Non-polar Mixtures". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/03992921846950679532.
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Hohls, Jeanette. "Theories and computation of second virial coefficients of electromagnetic phenomena". Thesis, 1997. http://hdl.handle.net/10413/6050.
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Many bulk properties of gases depend linearly on the gas density at lower densities, but as the density increases departures from linearity are observed. The density dependence of a bulk property Q may often be discussed systematically by expanding Q as a power series in l/Vm, to yield: Q=Aq+Bq/Vm+Cq/V2m+..., where Bq is known as the second virial coefficient of the property Q. Aq is the ideal gas value of Q, and Bq describes the contribution of molecular pair interactions to Q. Theories of Q may be regarded as having two main components, one describing how the
presence of a neighbour of a given molecule can enhance or detract from its contribution to Q, and the other the molecular interaction energy which determines the average geometry of a pair encounter. The latter component is common to all theories, and the former requires detailed derivations for each specific bulk property Q. In this work we consider the second virial coefficients of five effects, namely the second pressure virial coefficient B(T), and also the second dielectric, refractivity, Kerr-effect and light-scattering virial coefficients, Be, Br, Bk, and Bp, respectively. Using a powerful computer algebraic manipulation package we have extended the existing dipole-induced-dipole (DID) theories of the second dielectric, refractivity and Kerr-effect virial coefficients to sufficiently high order to establish convergence in the treatment of both linear and non-linear gases. Together with the established linear theory of the second pressure virial coefficient, the extended theory of the second light- scattering virial coefficient developed by Couling and Graham, and their new non-linear theory of the second pressure and light-scattering virial coefficients, our new theories provide a comprehensive base from which to calculate
numerical values for the various effects for comparison with experiment. We have collected as much experimental data of the various second virial coefficients as possible, for a wide range of gases. The ten gases chosen for detailed study comprise a selection of polar and non-polar, linear and non-linear gases: the linear polar gases fluoromethane,
trifluoromethane, chloromethane and hydrogen chloride; the non-polar linear gases nitrogen, carbon dioxide and ethane; the non-linear polar gases sulphur dioxide and dimethyl ether; and the non-linear non-polar gas ethene. Using the best available measured or calculated molecular parameter data for these gases, together with the complete theories
for the second virial coefficients, we have attempted to find unique sets of molecular parameters for each gas which explain all the available experimental data. In general, reliable measured or calculated molecular properties are regarded as fixed, and only the Lennard-Jones and shape parameters in the molecular interaction energy are treated as best-fit parameters within the constraints of being physically reasonable.
Many of the apparent failures of second virial coefficient theories have been due to the lack of convergence in the series of terms evaluated. It is essential to work to sufficiently high orders in the polarizabilities and various multipole moments to ensure convergence for meaningful comparison with experiment. This often requires the manipulation of
extremely long and complicated expressions, not possible by the manual methods of our recent past. The advent of computer manipulation packages and fast processors for numerical integration have now enabled calculation to high orders, where the degree of convergence can be sensibly followed. Our efforts to describe all of the effects for which data is available met with mixed success. For four of the gases, fluoromethane, chloromethane, dimethyl ether and ethene, a unique parameter set was found for each which described all of the available effects reasonably well. For the three gases, trifluoromethane, nitrogen and sulphur dioxide, one interaction parameter set explained all but one of the effects for which data was available to within experimental uncertainty. For trifluoromethane the parameter set which yielded good agreement for B(T), Be, and Bk could not explain the observed values of Br, while for nitrogen one parameter set produced reasonable agreement for all of the effects except Bp and a different set, which yielded good agreement for Bp, did not explain the remaining four effects as well as the first set. The parameter set which
explained B(T), Bk and Bp very well for sulphur dioxide, yielded a value for Be, which was much larger than the experimental value, although of the correct sign and order of magnitude. Hydrogen chloride posed a special problem as data was only available for two of the effects, B(T) and Be. It was possible to find a set of interaction parameters in good agreement with the measured values of B(T), but the experimental data for Be was an order of magnitude larger than the largest calculated values. Since the remaining effects have not been measured for this gas it was not possible to test the theory more rigorously. For the remaining gases carbon dioxide and ethane, it was impossible, based on the existing measured values, to select a unique parameter set which explained all of the effects. In many of the cases where definite conclusions could not be drawn, it was not possible to decide whether the disagreement between theory and experiment was due to the large scatter and uncertainty of the experimental data or failure of the theory. However, there were very few instances of complete failure of the theory to explain experiment, and no one effect showed consistent disagreement, so that in general it may
be said that the mechanisms of the second virial coefficients under study are reasonably well understood. It would require more precise measurements of the various effects, as well as more measured or calculated molecular property tensor components, such as the
hyperpolarizability and the A- and C-tensors , to test the DID molecular interaction model more stringently.Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1997.
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Fang, Che-Ming, i 房哲名. "Osmotic pressure and virial coefficients of star polymer solutions : dissipative particle dynamics". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/28505596559777229958.
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碩士國立中央大學
化學工程與材料工程研究所
96
The osmotic pressure Π and virial coefficients ( B2 and B3 ) of linear and star polymers in good solvents are studied by dissipative particle dynamics simulations. The dependence of the osmotic pressure on the concentration c is directly caculated by considering two reservoirs separated by a semi- permeable, fictitious membrane. For linear polymers with chain length N, our simulation results confirm the scaling relations that B2 ~ N3ν in the dilute regime and Π ~ c2.70 in the semi-dilute regime. The exponent is greater than 9/4 due to the nature of soft beads. For star polymers, the scaling relations become B2 ~ Rg3 in dilute regime and Π λcα in semi-dilute regime. Both the prefactor λ and exponent α vary with the arm number but is independent of the arm length. As the arm number is increased, the exponent may rise from 2.7 to 3.07, which is qualitatively consistent with the experimental result.
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Couling, Vincent William. "Second light-scattering and Kerr-effect virial coefficients of molecules with linear and lower symmetry". Thesis, 1995. http://hdl.handle.net/10413/11278.
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Hryniewicki, Maciej Konrad. "Accurate and Efficient Evaluation of the Second Virial Coefficient Using Practical Intermolecular Potentials for Gases". Thesis, 2011. http://hdl.handle.net/1807/29559.
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The virial equation of state p = ρRT[
1 + B(T) ρ + C(T) ρ2 + · · ·] for high pressure and density gases is used for computing chemical equilibrium properties and mixture compositions of strong shock and detonation waves. The second and third temperature-dependent virial coefficients B(T) and C(T) are included in tabular form in computer codes, and they are evaluated by polynomial interpolation. A very accurate numerical integration method is presented for computing B(T) and its derivatives for tables, and a sophisticated method is introduced for interpolating B(T) more accurately and efficiently than previously possible. Tabulated B(T) values are non-uniformly distributed using an adaptive grid, to minimize the size and storage of the tables and to control the maximum relative error of interpolated values. The methods introduced for evaluating B(T) apply equally well to the intermolecular potentials of Lennard-Jones in 1924, Buckingham and Corner in 1947, and Rice and Hirschfelder in 1954.
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Prickett, Richelle Catherine. "The application of the multisolute osmotic virial equation to cryobiology". Phd thesis, 2009. http://hdl.handle.net/10048/849.
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Thesis (Ph. D.)--University of Alberta, 2010.Title from pdf file main screen (viewed on Jan. 15, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemical Engineering and Medical Sciences, Departments of Chemical and Materials Engineering and Medical Sciences - Laboratory Medicine and Pathology, University of Alberta. Includes bibliographical references.
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Pham, Van Tat [Verfasser]. "Ab initio calculation of intermolecular potentials, prediction of second virial coefficients for dimers H2-H2, H2-O2, F2-F2 and H2-F2, and Monte Carlo simulations of the vapor-liquid equilibria for hydrogen and fluorine / vorgelegt von Tat Pham Van". 2006. http://d-nb.info/982696396/34.
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Втулкина, Е. Д., i E. D. Vtulkina. "Математическое и компьютерное моделирование термодинамических свойств магнитных жидкостей : магистерская диссертация". Master's thesis, 2015. http://hdl.handle.net/10995/36219.
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Мы исследуем термодинамические свойства магнитных жидкостей с небольшими и умеренными значениями параметра диполь-дипольного взаимодействия в отсутствии внешнего магнитного поля. Магнитные жидкости моделируются монодисперсной системой дипольных твердых сфер. Построена теория, основанная на обратном кумулянтном преобразовании вириального разложения свободной энергии Гельмгольца в ряд по плотности. Методом компьютерного моделирования Mayer Sampling получены данные для пятого вириального коэффициента. По данным компьютерного моделирования получены аналитические выражения для четвертого и пятого вириальных коэффициентов. В работе были определены аналитические выражения для свободной энергии, давления, химического потенциала и коэффициента градиентной броуновской диффузии. Построенная теория хорошо согласуется с данными компьютерного моделирования в широкой области концентраций феррочастиц (φ≤4) и интенсивности межчастичного диполь-дипольного взаимодействия (λ≤4).We investigate thermodynamic properties of ferrofluids with low and intermediate dipolar coupling constant. The model of dipolar hard spheres is observed. In this work a new theory is constructed based on the transformation of the virial expansion for the Helmholtz free energy into a logarithmic form. Analytical expressions of the forth and the fifth virial coefficients are obtained on the basis of numerical results of Mayer-sampling calculation. In this work analytical expressions for free energy, chemical potential, pressure and gradient diffusion coefficient were obtained. The comparison between theory and computer simulation shows good agreement for dipolar coupling constant λ≤4 and for particle volume fraction φ≤4.