Rozprawy doktorskie: „COEFFICIENTS FOR INTERACTION”

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Yilmazok, Ozgun. "An Investigation Of Accuracy Of Inertial Interaction Analyses With Frequency-independent Impedance Coefficients". Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12609030/index.pdf.

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AN INVESTIGATION OF ACCURACY OF INERTIAL INTERACTION ANALYSES WITH FREQUENCY-INDEPENDENT IMPEDANCE COEFFICIENTS Yilmazok, Ö
zgü
n M.S., Department of Civil Engineering Supervisor: Assoc. Prof. Dr. B. Sadik Bakir November 2007, 79 pages The inertial interaction between the soil and structure alters dynamic response characteristics of a structure due to foundation deformability, such that the flexibility and energy dissipation capability of surrounding soil may lead to a significant increase in period and damping of structural oscillations. The inertial interaction analyses can be accomplished through utilisation of frequency dependent foundation impedance coefficients that are reported in literature for various soil conditions and foundation types. However, such analyses should be performed in frequency domain, and applicable to only cases that linear structural response is considered. Alternatively, equivalent frequencyindependent foundation impedance coefficients can be employed, such that a constant excitation frequency is assumed in calculation of these coefficients. In this study, it is assumed that the fundamental frequency of a fixed-base structure, which can be obtained through employing available empirical relationships or a modal analysis, can be substituted for excitation terms in impedance expressions. The error induced in calculation of peak structural distortions is investigated through comparisons of structural response due to frequency-dependent and frequency-independent foundation impedance coefficients. For analyses, a linear single-degree of freedom oscillator is considered for modeling the structure. The frequency-dependent impedance of a rigid disk foundation resting on elastic halfspace is simulated by a limited number of discrete elements. The response calculations are performed in frequency domain, through employing 72 acceleration records. It is concluded that, the natural frequency of fixed-base building can be considered as effective excitation frequency for calculation of foundation impedance coefficients, when the effect of inertial interaction on structural response is moderate. Through employing equivalent-linear approximation for the structural response, it is shown that the conclusion is also valid in cases that nonlinear structural response is considered. However, when the inertial interaction has more profound effects on the structural response, the use of natural frequency of flexible-base structure, which is calculated iteratively due to its dependence on foundation-impedance factors is recommended.

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Ticona, A. M., M. A. Rosales i J. D. Orihuela. "Correction coefficients of distortion and vibration period for buildings due to soil-structure interaction". OP Publishing Ltd, 2020. http://hdl.handle.net/10757/656571.

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The present research analyzed the influence of the soil structure interaction (SSI) in buildings, varying geotechnical parameters and height, considering 3 international codes. The responses obtained from the structures taking into account the SSI, were compared with the responses of fixed-base buildings, being the main control variables: the period and the drift. It was determined that the estimated range in which the period of the structure increases is from 30 to 98%, demonstrating the influence of considering soil flexibility. Due to the variability of the responses obtained, an adjustment factor is proposed to predict said amplification of the control variables, depending on the height of the building and the ground.

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Randall, Richard John. "Fluid-structure interaction of submerged shells". Thesis, Brunel University, 1990. http://bura.brunel.ac.uk/handle/2438/5446.

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A general three-dimensional hydroelasticity theory for the evaluation of responses has been adapted to formulate hydrodynamic coefficients for submerged shell-type structures. The derivation of the theory has been presented and is placed in context with other methods of analysis. The ability of this form of analysis to offer an insight into the physical behaviour of practical systems is demonstrated. The influence of external boundaries and fluid viscosity was considered separately using a flexible cylinder as the model. When the surrounding fluid is water, viscosity was assessed to be significant for slender structural members and flexible pipes and in situations where the clearance to an outer casing was slight. To validate the three-dimensional hydroelasticity theory, predictions of resonance frequencies and mode shapes were compared, with measured data from trials undertaken in enclosed tanks. These data exhibited differences due to the position of the test structures in relation to free and fixed boundaries. The rationale of the testing programme and practical considerations of instrumentation, capture and storage of data are described in detail. At first sight a relatively unsophisticated analytical method appeared to offer better correlation with the measured data than the hydroelastic solution. This impression was mistaken, the agreement was merely fortuitous as only the hydroelastic approach is capable of reproducing-the trends recorded in the experiments. The significance of an accurate dynamic analysis using finite elements and the influence of physical factors such as buoyancy on the predicted results are also examined.

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Nordanstorm, Nika. "Evaluation of distribution coefficients (KOC and Kd) for per- and polyfluoroalkyl substances". Thesis, Linnéuniversitetet, Institutionen för biologi och miljö (BOM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-101693.

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The dominating factors affecting sorption of per- and polyfluoroalkyl substances (PFAS) remain subject of research and debate. Traditionally, distribution coefficients (e.g., Kd and KOC) are used to calculate the fractionation of the contaminant between soil and water, to estimate leaching and subsequently the risks it imposes reaching water reservoirs. Research has aimed to establish the sorption mechanisms for PFAS but, due to the complexity of interactions between the substance specific physiochemical properties and geochemical sorbent characteristics, it has shown to be a complicated task. For PFOS, one of the most commonly encountered PFAS, the Swedish Geotechnical Institute (SGI) recommends using the 10th percentile of a small data set for the organic carbon-water distribution coefficient KOC (500 L/kg) and multiply this with the organic content of the in-situ soil to obtain the soil-water distribution coefficient (Kd). The result of this study shows that this method is insufficient to obtain a good approximation of the mobility of PFOS at a contaminated site. With a review of recent research on PFAS sorption and a case study performed at Stockholm Arlanda Airport, this study concludes that as of today, and due to PFAS potent mobility, well measured field coefficients for each soil type present in the soil profile and an elaborate geohydrological model is necessary to estimate PFAS environmental transport, fate and associated risks. It also concludes that parameters such as anionic exchange capacity and soil protein content may be highly relevant to estimate PFAS sorption.

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Stamos, Dimitrios Georgios. "Experimental Analysis of the Interaction of Water Waves With Flexible Structures". Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/27567.

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An experimental investigation of the interaction of water waves with flexible structures acting as breakwaters was carried out. Wave profiles, mapped out by water level measuring transducers, were studied to provide information on the performance of different breakwater models. A new signal analysis procedure for determining reflection coefficients based on wavelet theory was developed and compared to a conventional method. The reliability of using wavelet analysis to separate a partial standing wave into incident and reflected wave components was verified with a numerical example. It was also verified by the small variance in the estimates of the incident wave height from independent experimental measurements. Different geometries of rigid and flexible structures were constructed and examined. Reflection, transmission and energy loss coefficients were obtained over them. The influence of various properties of the models, such as the width and the internal pressure, on the effectiveness in reflecting or absorbing the incident wave energy was determined. Various factors which affect the performance of the breakwater, including the water depth, the wave length and the wave amplitude, were measured and documented. Suspended and bottom-mounted models were considered. The flow field over and near a hemi-cylindrical breakwater model was also examined using a flow visualization technique. An overall comparison among the models has also been provided. The results showed that the rectangular models, rigid and flexible, are the most effective structures to dissipate wave energy. The flow visualization technique indicated that the flow conforms with the circular geometry of a hemi-cylindrical breakwater model, yielding no flow separation.
Ph. D.

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Crofoot, Robert F. "Investigations of scalar transfer coefficients in fog during the Coupled Boundary Layers and Air Sea Transfer Experiment : a case study". Thesis, Monterey, California. Naval Postgraduate School, 2004. http://hdl.handle.net/10945/1202.

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The uncertainty in the determination of the momentum and scalar fluxes remains one of the main obstacles to accurate numerical forecasts in low to moderate wind conditions. For example, latent heat fluxes computed from data using direct covariance and bulk aerodynamic methods show that there is good agreement in unstable conditions when the latent heat flux values are generally positive. However, the agreement is relatively poor in stable conditions, particularly when the moisture flux is directed downward. If the direct covariance measurements are indeed accurate, then they clearly indicate that the bulk aerodynamic formula overestimate the downward moisture flux in stable conditions. As a result, comparisons of the Dalton number for unstable and stable conditions indicate a marked difference in value between the two stability regimes. Investigations done for this thesis used data taken primarily at the Air-Sea Interaction Tower (ASIT) during the Coupled Boundary Layers and Air-Sea Transfer (CBLAST) Experiment 2003 from the 20-27 August 2003. Other data from the shore based Martha's Vineyard Coastal Observatory (MVCO) and moored buoys in the vicinity of the ASIT were also incorporated. During this eight day period, the boundary layer was often characterized by light winds, a stably stratified surface layer and a swell dominated wave field. Additionally, the advection of warm moist air over cooler water resulted in fog formation and a downward flux of moisture on at least three occasions. Therefore, a primary objective of this thesis is to present a case study to investigate the cause of this shortcoming in the bulk formula under these conditions by examining the physical processes that are unique to these boundary layers. Particular attention will be paid to the behavior of the Dalton number in a stable marine atmospheric boundary layer under foggy conditions using insights derived from the study of fog formation and current flux parameterization methods.

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BOULANGER, DANIEL. "Theorie du champ de ligandes des coefficients de couplage orbite-reseau et spin-reseau des ions d**(5) dans les composes ii-vi". Paris 6, 1988. http://www.theses.fr/1988PA066098.

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Developpement d'un modele moleculaire semi-empirique pour les ions d**(5). L'application aux calculs des coefficients de couplage orbite-reseau et des coefficients de couplage spin-reseau a donne de tres bons resultats

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8

Mahfouf, Ali. "Calcul des coefficients de transport dans des plasmas hors de l'équilibre". Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22719/document.

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Les propriétés de transport à haute température dans les gaz et/ou dans les plasmas ont une importance capitale dans différents domaines, à savoir dans le domaine de technologie de coupure à arc, plasmas de coupure, de soudure ou de gravure. La connaissance des coefficients de transport est nécessaire pour toute modélisation faisant intervenir les équations hydrodynamiques. Dans le cadre de la théorie cinétique des gaz dilués, une solution approchée de l’équation intégro-différentielle de Boltzmann régissant les fonctions de distribution a été proposée par Chapman-Enskog. Les coefficients de transport sont calculés classiquement par la méthode de Chapman-Enskog via les intégrales de collision. Dans le cadre de notre étude nous avons développé, dans un premier temps, un code numérique permettant l’obtention de ces intégrales de collision en tenant compte des singularités qui peuvent apparaître dans le calcul des sections efficaces relatives aux interactions entre les particules constituant les gaz et/ou les plasmas. Dans un second temps nous avons étudié l’influence du choix des paramètres des potentiels d’interaction sur les coefficients de transport. Par la suite, nous avons utilisé le code numérique ainsi développé pour évaluer les coefficients de transport du plasma d’hélium en étudiant l’influence du choix de la méthode de calcul de composition chimique sur ces coefficients. Enfin, un modèle simplifié d’une interaction entre une onde électromagnétique et un plasma d’hélium a été proposé comme une application directe des coefficients de transport
Transport properties at high temperature in gases and/or in plasmas are of very importance in various fields, namely in the field of breaking technology in arc, cutting plasma, welding or burning. Knowledge of transport coefficients is necessary for any modeling involving hydrodynamic equations. As part of the kinetic theory of diluted gas, an approximate solution of the integro-differential Boltzmann equation governing distribution functions was proposed by Chapman-Enskog. Transport coefficients are classically computed using the method of Chapman-Enskog through the collision integrals. In our study we have developed, initially, a numerical code to obtain these collision integral taking into account the singularities that may occur in the calculation of the cross sections relating to interactions between particles forming the gas and/or plasmas. Secondly, we have studied the influence of the choice of parameters of interaction potentials on transport coefficients. Subsequently, we have used the numerical code developed for evaluating and helium plasma transport coefficients by studying the influence of the choice of method for calculating chemical composition on these coefficients. Finally, a simplified model of an interaction between an electromagnetic wave and a helium plasma has been proposed as a direct application of the transport coefficients

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Crofoot, Robert Farrington. "Investigations of scalar transfer coefficients in fog during the Coupled Boundary Layers and Air Sea Transfer experiment : a case study". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/39165.

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Thesis (S.M.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Ocean Engineering; and the Woods Hole Oceanographic Institution), 2005.
Includes bibliographical references (leaves 70-72).
The uncertainty in the determination of the momentum and scalar fluxes remains one of the main obstacles to accurate numerical forecasts in low to moderate wind conditions. For example, latent heat fluxes computed from data using direct covariance and bulk aerodynamic methods show that there is good agreement in unstable conditions when the latent heat flux values are generally positive. However, the agreement is relatively poor in stable conditions, particularly when the moisture flux is directed downward. If the direct covariance measurements are indeed accurate, then they clearly indicate that the bulk aerodynamic formula overestimate the downward moisture flux in stable conditions. As a result, comparisons of the Dalton number for unstable and stable conditions indicate a marked difference in value between the two stability regimes. Investigations done for this thesis used data taken primarily at the Air-Sea Interaction Tower (ASIT) during the Coupled Boundary Layers and Air-Sea Transfer (CBLAST) Experiment 2003 from the 20-27 August 2003. Other data from the shore based Martha's Vineyard Coastal Observatory (MVCO) and moored buoys in the vicinity of the ASIT were also incorporated.
(cont.) During this eight day period, the boundary layer was often characterized by light winds, a stably stratified surface layer and a swell dominated wave field. Additionally, the advection of warm moist air over cooler water resulted in fog formation and a downward flux of moisture on at least three occasions. Therefore, a primary objective of this thesis is to present a case study to investigate the cause of this shortcoming in the bulk formula under these conditions by examining the physical processes that are unique to these boundary layers. Particular attention will be paid to the behavior of the Dalton number in a stable marine atmospheric boundary layer under foggy conditions using insights derived from the study of fog formation and current flux parameterization methods.
by Robert Farrington Crofoot.
S.M.

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Ullberg, Malin. "Effects of pH and Cation Composition on Sorption of Per- and Polyfluoroalkyl Substances (PFASs) to Soil Particles". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-256415.

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Per- and polyfluoroalkyl substances (PFASs) have drawn great attention recently, due to their environmental persistence, potential toxicity and global distribution. PFAS is a large family of substances, characterized by a perflourinated carbon chain and a functional group. All PFASs are synthetic and have been widely used since the 1950s due to their unique properties of being both hydrophobic and oleophobic, making them useful for many industries. To be able to predict the fate of PFASs in the environment and to obtain detailed understanding of the transport processes, their partitioning behavior between soil particles and water depending on a range of parameters must be investigated. The aims of this study was to investigate the effects of pH, cation composition, functional group and perfluorocarbon chain length on sorption of PFASs to soil particles, by batch sorption experiment in laboratory scale. The laboratory-scale experiments were combined with modelling of the net charge to evaluate if net charge is a good predictor for sorption of PFASs to soil particles. 14 PFASs of varying length and functional groups were studied (PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFTeDA, PFBS, PFHxS, PFOS and FOSA). The effect on sorption of Na+, Ca2+ (two different concentrations) and Al3+ were investigated at pH-range 3-6. Modelling of net charge was carried out in the geochemical model Visual MINTEQ. The soil had 45% organic carbon content. The adsorption of PFASs was strongly correlated with perfluorocarbon chain length, showing a stronger adsorption to particles with increasing perfluorocarbon chain length (i.e. more hydrophobic). The relation between sorption (represented by the distribution coefficient log Kd) and perfluorocarbon chain length was linear for all PFSAs and C3 to C10 PFCAs. The PFSAs (sulfonate functional group) sorbed stronger to soil particles than the PFCAs (carboxylic functional group), and FOSA (sulfonamide functional group) sorbed the strongest. For most PFCAs, (C5-C13) there was a trend of decreasing log Kd (i.e. decreased sorption) with increasing pH, due to pH-dependent changes of the soil particle surfaces. For short and intermediate perfluorocarbon chain length PFCAs (C5-C8) and for PFHxS among the PFSAs, cations had a clear effect on sorption. Aluminium ions (trivalent, Al(NO3)3) had the largest effect, followed by calcium (divalent, Ca(NO3)2) where higher concentration resulted in stronger sorption. Sodium (univalent, NaNO3) had the least influence on sorption. The net charge modelled with Visual MINTEQ takes into account many parameters (including pH) that affect the surface charge and sorption of PFASs to soil particles. When comparing log Kd for the different PFASs with pH and net negative charge, net charge was a better predictor of sorption of PFASs to soil particles than solution pH alone.
Per- och polyfluoroalkylsubstanser (PFAS:er) har dragit stor uppmärksamhet till sig på senare tid, på grund av deras persistenta egenskaper, potentiella toxicitet och globala utbredning. PFAS är en stor grupp ämnen, kännetecknad av en perflourinerad kolkedja och en funktionell grupp. Alla PFAS är syntetiska och har använts i stor utsträckning sedan 1950-talet på grund av deras unika egenskaper av att vara både vatten- och fettavstötande, vilket gör dem användbara för många industriella tillämpningar. För att kunna förutsäga var dessa föroreningars hamnar i miljön och få mer detaljerad förstående för transportprocesserna, måste deras fördelningbeteende mellan jordpartiklar och vattenundersökas för en rad olika parametrar. Syftet med denna studie var att undersöka effekterna av förändrat pH, katjonsammansättning, funktionell grupp och perfluorkolkedjelängd på sorption av PFAS:er till jordpartiklar. Detta gjordes med sorptionsexperiment i laboratorieskala. Laboratorieexperimentet kompletterades med modellering av nettoladdning, för att se huruvida detta väl kunde förklara sorptionen till jordpartiklar. 14 PFAS:er av varierande längd och med tre olika funktionella grupper studerades (PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFTeDA, PFBS, PFHxS, PFOS och FOSA). Effekten på sorption av Na+, Ca2+ (två olika koncentrationer) och Al3+ undersöktes vid pH-intervallet 3-6. Modellering av nettoladdning utfördes i den geokemiska modellen Visual MINTEQ. Jorden som användes hade en halt av organiskt kol på 45%. Adsorptionen av PFAS:er var starkt positivt korrelerad med kedjelängden på de perfluorinerade kolkedjan. Ju längre kolkedja (dvs. mer hydrofob), desto starkare adsorption till partiklar. Relationen mellan sorptionen (här uttryckt som partitioneringskofficienten log Kd) och kedjelängd var linjär för alla PFSA och för C3 till C10 för PFCA. PFSA (sulfonat) adsorberade starkare än PFCA (karboxyl), och FOSA (sulfonamid) adsorberades starkast. För de flesta PFCA, (C5-C13) fanns en allmän trend där log Kd (dvs. sorption) minskade med ökande pH, på grund av pH-beroende förändringar på jordpartiklarna. För korta och medellånga PFCA (C5-C8) och för PFHxS hade katjonsammansättningen en tydlig effekt på sorptionen. Aluminiumjoner (trevärd, Al(NO3)3) hade den största effekten, följt av kalcium (tvåvärd, Ca(NO3)2) där den högre koncentrationen resulterade i starkare sorption. Natrium (envärd, NaNO3) hade minst påverkan på sorptionen till jordpartiklar. Visual MINTEQ tar hänsyn till många parametrar (inklusive pH), när nettoladdningen på jordpartiklarnas yta räknas ut. När log Kd för olika PFAS:er jämfördes med endera pH eller negativ nettoladdning, drogs slutsatsen att nettoladdning korrelerade bättre med sorption än pH.

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Wiranata, Anton. "Transport Coefficients of Interacting Hadrons". Ohio University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1314733650.

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Jacob, Xavier. "Applications de l' interaction d' ondes élastiques à la mesure des propriétés non linéaires des matériaux et à la caractérisation de champs de pression". Paris 7, 2005. http://www.theses.fr/2005PA077030.

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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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Milesi, Paul. "Interactions between waves and new generations of brakewaters with small footprint". Thesis, Ecole centrale de Marseille, 2019. http://www.theses.fr/2019ECDM0003/document.

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De nos jours, le respect de l'environnement est une obligation dans le cadre de travaux maritimes. Les caissons en béton verticaux à plaques poreuses sont souvent la solution technique privilégiée pour agrandir les ports existants et / ou améliorer l'agitation des bassins. L'empreinte au sol est réduite et la demande en matériaux de carrière est moins importante par rapport aux digues en enrochement classiques. Récemment, des systèmes alternatifs aux caissons en béton verticaux ont été conçus. Les structures amortisseuses de la houle à enrochements verticalisés sont constituées d'une structure métallique entourant des blocs. Ce type de structure offre des avantages environnementaux, une perméabilité aux courants et une bonne performance hydrodynamique. Ce travail de thèse visait à développer un nouveau code 3D-BEM facile à utiliser et intégrant les écoulements en milieux poreux. Des géométries innovantes sont testées comme des gabions espacés avec une chambre d’expansion ou un mélange de plaques poreuses et de milieux poreux.La description des écoulements dans un milieu poreux est une question complexe. Navier-Stokes moyenné au sens de Reynolds (RANS) est le processus mathématique communément utilisé pour modéliser les écoulements en milieux poreux. Ce dernier est considéré comme un milieu continu homogène. L'équation bien connue de Forchheimer étendue décrit les forces volumiques appliquées à l'écoulement par un milieu poreux à travers des coefficients de résistance et d'inertie. Ces recherches ont été l’occasion d’examiner ces coefficients, notamment celui d'inertie mal connu dans le cas d’un milieu poreux. Il joue un rôle majeur pour les écoulements à très faible KC se produisant dans les couches internes des digues poreuses. Une analyse de la littérature sur les écoulements de milieux poreux a été entreprise. Le code numérique appelé Diffra3D a été développé. Il a ensuite été utilisé pour rechercher des coefficients de résistance de milieux poreux à l'aide de données provenant de trois campagnes expérimentales : un test de sloshing sur hexapode et deux études classiques de transmission/réflexion en canal à houle. Celles-ci ont également été l'occasion de tester et de calibrer le code. De nouvelles géométries de structures poreuses ont ensuite été testées expérimentalement et numériquement.Deux nouvelles valeurs de coefficients de résistance d'un milieu poreux sont proposées pour les écoulements à très faibles KC. Certaines caractéristiques intéressantes concernant le coefficient d'inertie CM d'un milieu poreux sont également développées. Ce sujet de recherche mériterait encore d’être approfondi pour tenter de trouver une ou plusieurs loi(s) empirique(s) décrivant l’évolution du coefficient d'inertie dans ce régime spécifique d’écoulement. Le code Diffra3D fonctionne de façon satisfaisante pour modéliser les écoulements en milieu poreux. Il est cependant limité aux vagues à faibles cambrures. Tout l'enjeu est de bien caractériser le milieu poreux étudié. L'utilisation de Diffra3D a permis de montrer que les structures poreuses verticales innovantes, telles que les gabions espacés, ont entièrement leur place en tant que digues amortisseuses de la houle respectueuses de l'environnement. Elles pourraient être couramment utilisées dans le futur
Nowadays the respect of the environment is an obligation in maritime works. Vertical concrete caissons with porous plates are often the number one technical solution to enlarge existing ports and/or to improve the agitation of the basins. The footprint is reduced and the demand in quarry materials is less important compared to classical riprap breakwaters. Recently, alternative systems to vertical concrete caissons have been designed. Vertical riprap breakwaters are made of a metal framework enclosing blocks. This kind of structure offers environmental benefits, permeability for currents and a good hydrodynamic performance. This thesis work looks at developing a new 3D-BEM code that is easy to use and integrates porous media. Innovative geometries are tested like spaced gabions with damping chamber or a mix of porous plates and porous media.Describing flows in porous media is an complex issue. Volume averaging method is the common mathematical process used to model porous media flows without drawing every grain of a porous medium. The well-known extended Forchheimer equation describes the volumetric forces applied to the flow by a porous medium through resistance and inertial coefficients. These researches were the occasion to look into this coefficients, especially the one of poorly understood inertia in the case of a porous medium. It plays a major role in very low-KC flows currently occurring in porous breakwaters apart from armour layer.First, a literature review on porous media flows was undertaken. In parallel, the numerical code called Diffra3D was produced. It was then used to look for resistance coefficients of porous media through data coming from three experimental campaigns : one sloshing test on hexapode and two classical reflection-transmission studies in a wave tank. These campaigns were also the occasion to test and calibrate the code. New geometries of porous structures were then tested experimentally and numerically. Two new values of resistance coefficients of a porous medium are proposed. Some interesting features concerning the inertia coefficient CM of a porous medium are also developed. In simulations, we observe that the hydrodynamic behaviour of porous structures in low-KC flows is very sensitive to the coefficient of inertia. This research topic would still deserve further studies in order to find empirical law(s) for the inertia coefficient of a porous medium. The code Diffra3D performs well to model porous media flows. However, it is limited to waves with low steepness. The challenge is to properly characterise the porous medium. This research has shown that innovative porous structures like spaced gabions have proven their place as environmentally-friendly damping breakwaters. They may be commonly used in the future

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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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Mokeddem, Abdelhammid. "Modélisation géomécanique et probabiliste des rideaux de palplanches : prise en compte de l’interaction sol-structure et de la variabilité spatiale du sol". Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0057/document.

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Le comportement géomécanique des ouvrages géotechniques à l’exemple des rideaux de palplanches est entaché d’incertitudes épistémiques liées aux hypothèses régissant le modèle géomécanique de calcul, mais aussi d’incertitudes aléatoires liées à la variabilité spatiale du sol. L’objectif principal de cette thèse est de mieux appréhender l’effet de ces incertitudes sur le comportement d’un rideau de palplanches. Pour cela le présent mémoire s’articule autour de quatre points principaux : Le premier point est relatif d’une part à l’analyse des hypothèses utilisées pour la modélisation géomécanique d’un rideau de palplanches et d’autre part à l’extension de la méthode des coefficients de réaction d’un système unidimensionnel basé sur une poutre et des appuis élastoplastiques à un système bidimensionnel de plaque orthotrope sur le même type d’appuis (MISS-CR-PLQ). Le deuxième point concerne la modélisation de la variabilité spatiale du sol. Après une comparaison entre deux méthodes de génération de champs aléatoires nous avons retenu la méthode Circulant Embedding pour son efficience. Plusieurs études paramétriques ont été menées pour analyser les effets des hypothèses prises lors de la génération des champs aléatoires. Le troisième point concerne la mise en place d’une démarche mécano-fiabiliste permettant d’intégrer la variabilité spatiale du sol pour le cas des rideaux de palplanches. Le quatrième point est consacré à l’application de la démarche développée pour un cas d’étude à travers des analyses probabilistes et fiabilistes. L’influence des paramètres statistiques (e.g. les longueurs de corrélations, la corrélation croisée, …), mécanique et géométrique a été étudiée
The geomechanical behaviour of geotechnical structures such as sheet pile walls is subjected to epistemic uncertainties due to geomechanical models’ assumptions and also the aleatory uncertainties which could be related to the soil spatial variability. The main objective of this thesis is to gain more insight into the effect of these uncertainties on the sheet pile behaviour. To this end, this thesis focuses on four main issues: The first one is related on the one hand to the analysis of the used geomechanical hypotheses for modelling of retaining walls. On the other hand, to extend the one-dimensional subgrade reaction method which is based on a beam relying on elastoplastic supports to a two-dimensional system that call to an orthotropic plate relying on the same supports (MISS-CR-PLQ). The second issue concerns the soil spatial variability modelling. After a key comparison between two random field generation methods, we selected the Circulating Embedding method for its efficiency. Several parametric studies have been conducted to analyse the effects of different assumptions of random field generation. The third issue is related to the implementation of the proposed mechanical-reliability approach taking into account the soil spatial variability. The last issue is devoted to the application of the developed approach to a case study through probabilistic and reliability analyses. The influence of statistical parameters (e.g. correlation lengths, cross-correlation,...), mechanical and geometrical has been examined

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Mansoori, Behzad. "Tannin/protein interactions : effects on digestibility coefficients and endogenous losses in broilers". Thesis, University of Aberdeen, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301201.

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Tannic acid was shown to increase weight loss, and total excretion of endogenous dry matter, nitrogen, uric acid, amino acids, energy and minerals (calcium, magnesium and phosphorus) in broilers. There was a positive linear correlation between the amount of tannic acid dosed, and the weight and endogenous losses. A variation in the excretion of individual amino acids and minerals in response to dosed tannic acid was also noted. The mechanisms of increased endogenous losses of the birds as influenced by tannic acid were investigated and discussed. Feeding gelatin and casein significantly reduced the adverse effects of tannic acid on weight and endogenous losses. There were also significant improvements in digestibility coefficients and metabolisable energy values of protein in tannic acid dosed birds when the amount of the protein increased. Although in birds not dosed with tannic acid, casein had a higher digestibility and metabolisable energy compared to gelatin, tannic acid dosed birds showed greater improvements in digestibility coefficients when receiving gelatin. The above contrast was possible because of the higher affinity of gelatin for tannic acid compared to the casein. Polyethylene glycol (PEG) was shown to alleviate the weight and endogenous losses of tannic acid dosed birds not receiving protein. Polyethlene glycol also reduce the endogenous losses as well as improved the digestibility coefficients and metabolisable energy values of tannic acid dosed birds when receiving the lower amounts of gelatin (6g) or casein (6 and 12g). However, the effect of PEG was less apparent in tannic acid dosed birds receiving the higher amounts of gelatin (12 and 18g) and casein (18g). In conclusion, the presence of tannins in poultry diets are likely to increase the endogenous losses of organic materials as well as minerals, but this is likely to depend on the type and amount of diet ingredients such as proteins and additives (eg. PEG).

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18

Jeong, Dahai. "Laboratory Measurements of the Moist Enthalpy Transfer Coefficient". Scholarly Repository, 2008. http://scholarlyrepository.miami.edu/oa_theses/145.

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The enthalpy (sensible and latent heat) exchange processes within the surface layers at an air-water interface have been examined in 15-m wind-wave tunnel at the University of Miami. Measurements yielded 72 mean values of fluxes and bulk variables in the wind speed (referred to 10 m) range form 0.6 to 39 m/s, covering a full range of aerodynamic conditions from smooth to fully rough. Meteorological variables and bulk enthalpy transfer coefficients, measured at 0.2-m height, were adjusted to neutral stratification and 10-m height following the Monin-Obukhov similarity approach. The ratio of the bulk coefficients of enthalpy and momentum was estimated to evaluate Emanuel's (1995) hypothesis. Indirect "Calorimetric" measurements gave reliable estimates of enthalpy flux from the air-water interface, but the moisture gained in the lower air from evaporation of spray over the rough water remained uncertain, stressing the need for flux measurements along with simultaneous spray data to quantify spray's contribution to the turbulent air-water enthalpy fluxes.

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19

MacCuaig, Neil. "Precision measurements of gamma-ray attenuation coefficients in the energy range 15-1500 keV". Thesis, University of Surrey, 1986. http://epubs.surrey.ac.uk/847664/.

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The interactions of gamma-rays with matter have been studied for many years and there are accurate mathematical representations of the physical processes involved. Tabulations of the total interaction cross-section and of the major constituent processes have been produced which have an uncertainty of a few percent. In recent years the development of the tomographic scanner, first at EMI and then worldwide, has lead to the measurement of material interaction cross-sections with a precision of less than one percent, which is much less than the available tabulations. The form of the tabulations has also meant that data points must be interpolated from standard energy values, and so a large data base must be maintained if the values are stored on a computer. This is a time consuming and fairly inefficient process, especially if a micro-computer is used for the data base. In 1981 a compact, portable computer program was developed for the calculation of total interaction cross-sections (Jackson and Hawkes (1981)), which reproduced the tabulated data with a high precision (typically better than 0.5%) over a wide range of atomic number (1 < Z < 54) and energy (15 < E < 1500 keV). Although the computer code reproduces the theoretical data with high precision, the uncertainty in the original data is relatively large, this has prompted this experimental study to determine the agreement of the theoretical data values with experimental measurements. The precision desired from the experiments at the outset was 1%, which has been achieved in some, although not all, of the results presented here. The range of atomic number and gamma-ray energies of the materials tested in this study are from carbon (Z=6) to lead (Z=82) and from 15 to 1500 keV. This range has been determined largely by the sources and samples that have been available within the department, but it also represents the range of materials and energies that have been used in the industrial tomography group within this department. Isotopic sources and high resolution solid state detectors have been used to measure total cross-sections for the twelve elements used and up to 25 energies per sample (depending on the range of thicknesses available for the material). Many repeat runs have been done on each sample to increase the precision of the measurements presented here. The use of total interaction cross-sections for materials analysis has also been investigated for several situations and these are discussed and it is shown which methodsare possible and which are not with the precision used in these experiments. This study has to be seen as part of an ongoing process of experimentally producing total interaction cross-sections of higher and higher precision for comparison with theoretical formulations so that a deeper understanding of the underlying processes can be obtained. Within that framework some directions for future work have been outlined which will benefit from further study and a more detailed exploration.

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20

Byars, Beverly J. "Variation of the drag coefficient with wind and wave state". Thesis, Monterey, Calif. : Naval Postgraduate School, 1985. http://catalog.hathitrust.org/api/volumes/oclc/52763691.html.

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Heckmann, Klaus Verfasser], Jochen [Akademischer Betreuer] [Wambach i Michael [Akademischer Betreuer] Buballa. "Transport coefficients of strongly interacting matter / Klaus Heckmann. Betreuer: Jochen Wambach ; Michael Buballa". Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2011. http://d-nb.info/1105562417/34.

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Heckmann, Klaus [Verfasser], Jochen [Akademischer Betreuer] Wambach i Michael [Akademischer Betreuer] Buballa. "Transport coefficients of strongly interacting matter / Klaus Heckmann. Betreuer: Jochen Wambach ; Michael Buballa". Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2011. http://nbn-resolving.de/urn:nbn:de:tuda-tuprints-25889.

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Van, de Steen Cyril. "Modélisation des propriétés de transport des ions moléculaires de krypton et xénon pour l'optimisation des générateurs de plasma froids utilisant les gaz rares". Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30264/document.

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L'utilisation de plasmas froids à base de gaz rares (Rg) dans des applications biomédicales ainsi que dans la propulsion spatiale est en nette évolution. Pour optimiser ces réacteurs plasmas, une compréhension fine des processus ayant lieu dans ces réacteurs est nécessaire. Ce travail de thèse a pour objectif de fournir les données manquantes dans la littérature (coefficients de transport et réaction) en passant par des données mésoscopiques (sections efficaces) obtenues à partir de données microscopiques (potentiels d'interaction) pour le xénon et krypton dans leur gaz parent. Seul des plasmas froids composés d'un seul type d'atome sont considérés. Comme le krypton et le xénon sont des gaz rares, et ont donc, à l'état de neutralité peu/pas d'interaction entre eux. Par conséquent, seules les collisions ion - atome seront considérées. Du fait des faibles énergies des ions dans le plasma froid, seul les 6 premiers états excités du couple Rg2+ seront pris en compte. Ces 6 états seront classés en deux groupes, 2P1/2 et 2P3/2. Lors de ce travail, deux potentiels d'interaction différents disponibles dans la littérature sont utilisés et comparés pour les systèmes collisionnels Kr+/Kr et Xe+/Xe dans le calcul des sections efficaces. Pour les collisions impliquant des dimères ioniques (Kr2+/Kr et Xe2+/Xe), les potentiels d'interaction sont calculés à partir du modèle DIM (Diatomics In Molecules) qui est une combinaison des potentiels atomiques d'interaction neutre - neutre et ion - neutre. Les sections efficaces, requises pour obtenir les données mésoscopiques manquantes, sont calculées à partir de trois méthodes différentes. La première méthode est la méthode quantique qui permet, par une résolution de l'équation de Schrödinger, d'obtenir de manière exacte les sections efficaces à partir des potentiels d'interaction. Cette méthode exacte, étant grande consommatrice de temps de calcul, est utilisée en tant que référence pour valider les deux autres méthodes approchées. La seconde méthode, nommée semi-classique, est basée sur la même expression que la section efficace quantique mais utilise un déphasage approché (approximation JWKB), induit par le potentiel d'interaction, entre l'onde diffusée et l'onde incidente. [...]
The use of cold plasmas based on rare gases (Rg) in biomedical applications as well as in space propulsion is clearly evolving. To optimize these plasma reactors, a fine understanding of the processes taking place in these reactors is necessary. This thesis aims to provide the missing data in the literature (transport coefficients and reaction rates) through mesoscopic data (cross-sections) obtained from microscopic data (interaction potentials) for xenon and krypton in their parent gas. Only cold plasmas composed of a single type of atom are considered. As krypton and xenon are rare gases, and so have, in the neutral state little / no interaction between them. Therefore, only ion - atom collisions will be considered. Due to the low ion energies in the cold plasma, only the first 6 excited states of the Rg2+ pair will be taken into account. These 6 states will be classified in two groups, 2P1/2 and 2P3/2. In this work, two different interaction potentials available in the literature are used and compared for the Kr+/Kr and Xe+/Xe collision systems in the calculation of cross-sections. For collisions involving ionic dimers (Kr2+/Kr and Xe2+/Xe), the interaction potentials are calculated from the DIM model (Diatomics In Molecules) which is a combination of the atomic potentials of neutral - neutral and ionic - neutral interactions. The cross-sections required to obtain the missing mesoscopic data are calculated from three different methods. The first method is the quantum method which allows, by a resolution of the Schrödinger equation, to obtain exactly the cross-sections from the interaction potentials. This exact method, which consumes a lot of computation time, is used as a reference to validate the two other approximate methods. The second method, called semi-classical, is based on the same expression as the quantum cross section but uses an approximate phase shift (JWKB approximation), induced by the interaction potential, between the scattered wave and the incident wave. [...]

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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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Jacob, Xavier. "Applications de l'interaction d'ondes élastiques à la mesure des propriétés non-linéaires des matériaux et à la caractérisation de champs de pression". Phd thesis, Université Paris-Diderot - Paris VII, 2005. http://pastel.archives-ouvertes.fr/pastel-00001301.

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Ce manuscrit présente une étude de l'interaction non-linéaire d'ondes élastiques et de différentes techniques dédiées à la mesure des propriétés non-linéaires des matériaux et des champs de pression. Nous développons l'analogie entre fluides et solides pour les ondes longitudinales dans l'approximation quadratique. L'interaction de deux ondes (30 et 2,5 MHz), analogue à une modulation de phase, permet de mesurer les coefficients de non-linéarité de différents matériaux, sur des échantillons d'environ 10 mm d'épaisseur. Les résultats obtenus dans les fluides, les gels et les solides, notamment grâce aux améliorations de l'électronique, montrent la souplesse de cette technique. L'élasticité spécifique des solides mous rend possible des expériences de génération d'harmonique et d'interaction d'onde de cisaillement, qui illustrent les caractéristiques de la non-linéarité cubique et confirment l'influence des effets de diffraction. Ces derniers sont responsables de l'apparition d'harmoniques paires. Le palpeur d'élastographie 1D constitue une configuration expérimentale qui nous rapproche des applications. L'interférométrie optique a été appliquée à la mesure de fortes pressions dans l'eau (à la focale de transducteurs de forte puissance) et de très faibles déplacements (induit par la contrainte de radiation à la surface des solides). Les améliorations de l'optique, de l'électronique et du traitement du signal rendent possible l'étude des phénomènes d'acoustique non-linéaire.

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Yang, Xin. "Study of the hydrogen-tungsten interaction for fusion : measurement of the atomic reflection coefficient by laser spectroscopy". Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0232.

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Les interactions plasma surface (PSI) sont considérées comme l'un des défis scientifiques majeurs de la fusion nucléaire magnétique contrôlée. L'interaction entre les isotopes d'hydrogène et les matériaux de l’enceinte à plasma tels que le tungstène revêt une importance particulière. Le coefficient de perte en surface des isotopes atomiques (γ) est un point clé dans les études PSI. Il peut donner des informations sur le recyclage de l'hydrogène atomique à la paroi et constitue ainsi un paramètre clé dans les modélisations des interactions plasma surface. Le but de ce projet est de déterminer les coefficients de perte de surface de l'hydrogène atomique et du deutérium sur échantillons de tungstène (W) et de nitrure de tungstène (WN) en utilisant une technique de fluorescence induite par plasma (PIF) et une technique de fluorescence induite par laser à deux photons (TALIF). Ce projet s'effectue dans le réacteur CAMITER qui est un réacteur plasma radiofréquence à basse pression au laboratoire PIIM de l'Université Aix-Marseille
Plasma surface interaction (PSI) is considered to be one of the key scientific challenges in nuclear fusion. The interaction between hydrogen isotopes and plasma-facing materials such as tungsten is of particular importance. The atomic hydrogen isotope surface loss coefficient (γ) is a key point in PSI studies. It can give information on hydrogen isotope inventory and is an important input for modeling and theoretical work. The aim of this project is to determine atomic hydrogen and deuterium surface loss coefficients on tungsten (W) sample by using two-photon-absorption laser induced fluorescence (TALIF) and pulsed induced fluorescence (PIF) technique. This project is carried out in CAMITER reactor which is a low-pressure radio-frequency ICP reactor at PIIM laboratory in Aix-Marseille University

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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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Carlstedt, Emelie. "Soil‐structure interaction for bridges with backwalls : FE‐analysis using PLAXIS". Thesis, KTH, Bro- och stålbyggnad, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-36798.

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Bro 2004, BV Bro and the Eurocodes give guidelines for how to consider earth pressure induced by change in temperature and braking forces when designing backwalls. In this thesis those demands are investigated using PLAXIS for evaluation of the earth pressure. The results show that the model in PLAXIS corresponds quite well with the conventions in Bro 2004 and that modelling in PLAXIS gives reliable results. The demand in Bro 2004 that backwalls always shall be designed for passive earth pressure has been found to be pessimistic. In case of long bridges and short backwalls passive earth pressure is most often reached but for shorter bridge lengths in combination with longer backwalls this is almost never the case. It was also found that PLAXIS is sensitive and that the structure of the model and the choice of input are essential. A model in PLAXIS doesn’t make the design more effective but it may be a good tool for analysing the effect of the earth pressure combined with other effects such as the patterns for displacement as well as moment- and force distributions.
Bro 2004, BV Bro och Eurocode ger råd för hur jordtryck som uppkommer på grund av temperaturändring och bromskraft skall tas hänsyn till vid dimensionering av ändskärmar. I detta examensarbete undersöks dessa dimensioneringskrav med hjälp av PLAXIS för att göra en bedömning av jordtrycket. Resultaten visar att modellen i PLAXIS överensstämmer ganska väl med de konventioner som ges i Bro 2004 och att PLAXIS ger tillförlitliga resultat. Kravet att ändskärmar alltid ska dimensioneras för passivt jordtryck visade sig vara pessimistiskt. I fall med långa broar och korta ändskärmar nås ofta passivt jordtryck men för kortare broar med djupare ändskärmar är detta nästan aldrig fallet. PLAXIS visade sig vara känsligt för hur modellen byggs upp och vilka indata som ändvänds, varför dessa bör väljas försiktigt. En modell i PLAXIS medför inte en mer effektiv dimensionering men kan vara ett bra verktyg för analys av jordtryck i kombination med andra effekter så som förskjutningsmönster samt moment- och kraftdiagram.

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Trapp, Jamie Vincent. "Imaging and radiation interactions of polymer gel dosimeters". Thesis, Queensland University of Technology, 2003. https://eprints.qut.edu.au/15904/1/Jamie_Trapp_Thesis.pdf.

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Aim: The past two decades have seen a large body of work dedicated to the development of a three dimensional gel dosimetry system for the recording of radiation dose distributions in radiation therapy. The purpose of much of the work to date has been to improve methods by which the absorbed dose information is extracted. Current techniques include magnetic resonance imaging (MRI), optical tomography, Raman spectroscopy, x-ray computed tomography (CT) and ultrasound. This work examines CT imaging as a method of evaluating polymer gel dosimeters. Apart from publications resulting from this work, there has been only two other journal articles to date reporting results of CT gel dosimetry. This indicates that there is still much work required to develop the technique. Therefore, the aim of this document is to develop CT gel dosimetry to the extent that it is of use to clinical and research physicists. Scope: Each chapter in this document describes an aspect of CT gel dosimetry which was examined; with Chapters 2 to 7 containing brief technical backgrounds for each aspect. Chapter 1 contains a brief review of gel dosimetry. The first step in the development of any method for reading a signal is to determine whether the signal can actually be obtained. However, before polymer gel dosimeters can be imaged using a CT scanner, imaging techniques are required which are employable to obtain reliable readings. Chapter 2 examines the various artifacts inherent in CT which interfere with the quantitative analysis of gel dosimeters and a method for their removal is developed. The method for artifact reduction is based on a subtraction technique employed previously in a feasibility study and a system is designed to greatly simplify the process. The simplification of the technique removes the requirement for accurate realignment of the phantom within the scanner and the imaging of calibration vials is enabled. Having established a method by which readings of polymer gel dosimeters can be obtained with CT, Chapter 3 examines the CT dose response. A number of formulations of polymer gel dosimeter are studied by varying the constituent chemicals and their concentrations. The results from this chapter can be employed to determine the concentration of chemicals when manufacturing a polymer gel dosimeter with a desired CT dose response. With the CT dose response characterised in Chapter 3, the macroscopic cause of the CT signal is examined in Chapter 4. To this end direct measurement of the linear attenuation coefficient is obtained with a collimated radiation source and detector. Density is measured by Archimedes' principle. Comparison of the two results shows that the cause of the CT signal is a density change and the implications for polymer gel dosimetry are discussed. The CT scanner is revisited in Chapter 5 to examine the CT imaging techniques required for optimal performance. The main limitation of the use of CT in gel dosimetry to date has been image noise. In Chapter 5 stochastic noise is investigated and reduced. The main source of non-stochastic noise in CT is found and imaging techniques are examined which can greatly reduce this residual noise. Predictions of computer simulations are verified experimentally. Although techniques for the reduction of noise are developed in Chapter 5, there may be situations where the noise must be further reduced. An image processing algorithm is designed in Chapter 6 which employs a combination of commonly available image filters. The algorithm and the filters are tested for their suitability in gel dosimetry through the use of a simulated dose distribution and by performing a pilot study on an irradiated polymer gel phantom. Having developed CT gel dosimetry to the point where a suitable image can be obtained, the final step is to investigate the uncertainty in the dose calibration. Methods used for calibration uncertainty in MRI gel dosimetry to date have either assumed a linear response up to a certain dose, or have removed the requirement for linearity but incorrectly ignored the reliability of the data and fit of the calibration function. In Chapter 7 a method for treatment of calibration data in CT gel dosimetry is proposed which allows for non-linearity of the calibration function, as well as the goodness of its fit to the data. Alternatively, it allows for the reversion to MRI techniques if linearity is assumed in a limited dose range. Conclusion: The combination of the techniques developed in this project and the newly formulated normoxic gels (not extensively studied here) means that gel dosimetry is close to becoming viable for use in the clinic. The only capital purchase required for a typical clinic is a suitable water tank, which is easily and inexpensively producible if the clinic has access to a workshop.

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Trapp, Jamie Vincent. "Imaging And Radiation Interactions Of Polymer Gel Dosimeters". Queensland University of Technology, 2003. http://eprints.qut.edu.au/15904/.

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Aim: The past two decades have seen a large body of work dedicated to the development of a three dimensional gel dosimetry system for the recording of radiation dose distributions in radiation therapy. The purpose of much of the work to date has been to improve methods by which the absorbed dose information is extracted. Current techniques include magnetic resonance imaging (MRI), optical tomography, Raman spectroscopy, x-ray computed tomography (CT) and ultrasound. This work examines CT imaging as a method of evaluating polymer gel dosimeters. Apart from publications resulting from this work, there has been only two other journal articles to date reporting results of CT gel dosimetry. This indicates that there is still much work required to develop the technique. Therefore, the aim of this document is to develop CT gel dosimetry to the extent that it is of use to clinical and research physicists. Scope: Each chapter in this document describes an aspect of CT gel dosimetry which was examined; with Chapters 2 to 7 containing brief technical backgrounds for each aspect. Chapter 1 contains a brief review of gel dosimetry. The first step in the development of any method for reading a signal is to determine whether the signal can actually be obtained. However, before polymer gel dosimeters can be imaged using a CT scanner, imaging techniques are required which are employable to obtain reliable readings. Chapter 2 examines the various artifacts inherent in CT which interfere with the quantitative analysis of gel dosimeters and a method for their removal is developed. The method for artifact reduction is based on a subtraction technique employed previously in a feasibility study and a system is designed to greatly simplify the process. The simplification of the technique removes the requirement for accurate realignment of the phantom within the scanner and the imaging of calibration vials is enabled. Having established a method by which readings of polymer gel dosimeters can be obtained with CT, Chapter 3 examines the CT dose response. A number of formulations of polymer gel dosimeter are studied by varying the constituent chemicals and their concentrations. The results from this chapter can be employed to determine the concentration of chemicals when manufacturing a polymer gel dosimeter with a desired CT dose response. With the CT dose response characterised in Chapter 3, the macroscopic cause of the CT signal is examined in Chapter 4. To this end direct measurement of the linear attenuation coefficient is obtained with a collimated radiation source and detector. Density is measured by Archimedes' principle. Comparison of the two results shows that the cause of the CT signal is a density change and the implications for polymer gel dosimetry are discussed. The CT scanner is revisited in Chapter 5 to examine the CT imaging techniques required for optimal performance. The main limitation of the use of CT in gel dosimetry to date has been image noise. In Chapter 5 stochastic noise is investigated and reduced. The main source of non-stochastic noise in CT is found and imaging techniques are examined which can greatly reduce this residual noise. Predictions of computer simulations are verified experimentally. Although techniques for the reduction of noise are developed in Chapter 5, there may be situations where the noise must be further reduced. An image processing algorithm is designed in Chapter 6 which employs a combination of commonly available image filters. The algorithm and the filters are tested for their suitability in gel dosimetry through the use of a simulated dose distribution and by performing a pilot study on an irradiated polymer gel phantom. Having developed CT gel dosimetry to the point where a suitable image can be obtained, the final step is to investigate the uncertainty in the dose calibration. Methods used for calibration uncertainty in MRI gel dosimetry to date have either assumed a linear response up to a certain dose, or have removed the requirement for linearity but incorrectly ignored the reliability of the data and fit of the calibration function. In Chapter 7 a method for treatment of calibration data in CT gel dosimetry is proposed which allows for non-linearity of the calibration function, as well as the goodness of its fit to the data. Alternatively, it allows for the reversion to MRI techniques if linearity is assumed in a limited dose range. Conclusion: The combination of the techniques developed in this project and the newly formulated normoxic gels (not extensively studied here) means that gel dosimetry is close to becoming viable for use in the clinic. The only capital purchase required for a typical clinic is a suitable water tank, which is easily and inexpensively producible if the clinic has access to a workshop.

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Patil, Deepak C. "Particle Interactions in Industrial Granular Systems: Experiments, Theory, and Simulations". Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/915.

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Granular media continue to be among the most manipulated materials found in various industries. Particle interactions in granular flow has fundamental importance in analyzing the performance of a wide range of key engineering applications such as hoppers, tumblers, and mixers etc. In spite of such ubiquitous presence, till date, our understanding of the granular flow is very limited. This restricts our ability to design efficient and optimal granular processing equipment. Additionally, the existing design abilities are also constrained by the number of particles to be analyzed, where, a typical industrial application involves millions of particles. This motivated the current research where investigations on the above limitations are pursued from three different angles: experimental, theoretical, and simulation. More specifically, this work aims to study particle-wall interaction and developing a computationally efficient cellular automata simulation framework for industrial granular applications. Towards this end, the current research is divided into two part: (I) energy dissipation during particle-wall interaction (II) cellular automata modeling. In part I, detailed experiments are performed on various sphere-thin plate combinations to measure the coefficient of restitution (COR) which is a measure of energy dissipation and it is one of the most important input parameters in any granular simulation. Alternatively, the energy dissipation measure also used to evaluate the elastic impact performance of superelastic Nitinol 60 material. Explicit finite element simulations are performed to gain detail understanding of the contact process and underlying parameters such as contact forces, stress-strain fields, and energy dissipation modes. A parametric study reveals a critical value of plate thickness above which the effect of plate thickness on the energy dissipation can be eliminated in the equipment design. It is found that the existing analytical expressions has limited applicability in predicting the above experimental and numerical results. Therefore, a new theoretical model for the coefficient of restitution is proposed which combines the effect of plastic deformation and plate thickness (i.e. flexural vibrations). In part II, in order to advance the existing granular flow modeling capabilities for the industry (dry and slurry flows) a cellular automata (CA) modeling framework is developed which can supplement the physically rigorous but computationally demanding discrete element method (DEM). These include a three-dimensional model which takes into account particle friction and spin during collision processing, which provides the ability to handle flows beyond solely the kinetic regime, and a multiphase framework which combines computational fluid dynamics (CFD) with CA to model multi-million particle count applications such as particle-laden flows and slurry flows.

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Qureshi, Tabussom. "Studying Transmembrane Helix Interactions in SDS micelles". Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34417.

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The importance of interactions between transmembrane domains of integral membrane proteins has been well-established in a range of essential cellular functions. Most integral membrane proteins also possess regions that lie on the exterior of the membrane that may influence the ability of these transmembrane domains to interact. We sought to test this hypothesis by quantifying the energetics of transmembrane helix self-association in the absence and presence of an amphipathic helix that can bind to the membrane surface. The model chosen for this study was the major coat protein (MCP) of M13 bacteriophage, which has an N-terminal amphipathic helix linked to its single transmembrane segment via a flexible linker. Dimerization of both full-length MCP and a peptide containing only the transmembrane domain (MCPTM) was studied by solution NMR in SDS micelles. We found that there was an increase in the apparent dimerization affinity in the absence of the N-terminal helix. However, this increase in apparent affinity could be attributed to differences in detergent-binding properties of the two polypeptides in monomeric versus dimeric states when the empty micelle was considered to be a participant in the dimer dissociation. Preliminary results from the integral membrane protein, p7 of the hepatitis C virus are also presented in this thesis. It has been demonstrated that p7 enhances viral infectivity and accumulation, and that this function may require oligomerization in the membrane. While we encountered limitations due to challenges in the generation of sufficient quantities of pure p7 samples, we were able to perform circular dichroism spectroscopy under conditions that may favor different oligomeric states. These studies suggest that there is a change in the degree of helicity upon oligomerization, and suggest that SDS could be a suitable system to characterize the interactions of the p7 oligomer in the future.

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Jouenne, Eric. "Etude des interactions entre la bêta-lactoglobuline et les composés d'arôme". Montpellier 2, 1997. http://www.theses.fr/1997MON20066.

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Ce travail s'inscrit dans le cadre global de l'etude des interactions entre les composes d'arome et les proteines. Pour notre part, nous avons choisi d'etudier la proteine majoritaire du lactoserum : la -lactoglobuline. Cette proteine globulaire presente une structure tridimensionnelle parfaitement caracterisee delimitant en son sein une poche hydrophobe susceptible de fixer de nombreux ligands apolaires. Les structures tertiaire et quaternaire de la -lactoglobuline etant tres sensibles a la composition du milieu, nous avons etudie l'effet de la concentration en proteine, du ph, de la force ionique et de l'uree sur les interactions avec les composes d'arome. L'utilisation de techniques d'analyses en espace de tete en mode statique et dynamique (dilution exponentielle) nous a permis de mettre en evidence et de mesurer les interactions entre la -lactoglobuline et quelques composes d'arome appartenant a differentes classes chimiques. La technique de chromatographie liquide dynamique a colonnes couplees qui permet de mesurer la solubilite d'un compose d'arome dans l'eau et dans une solution de -lactoglobuline, a conduit a la determination de quelques constantes d'affinite. Les resultats que nous avons obtenus montrent que les interactions sont principalement de nature hydrophobe. Les variations de la retention des composes d'arome par la -lactoglobuline en fonction du ph (2 a 11), de la force ionique et de la concentration en uree mettent en evidence le role fondamental de la structure tertiaire et suggerent la presence de deux sites de fixation potentiels. L'association des monomeres n'a que peu d'influence sur la retention des composes d'arome alors qu'une denaturation moderee de la proteine semble favorable a la fixation des ligands. L'exercice de phenomenes competitifs simples entre ligands pour le ou les sites de fixations sur la -lactoglobuline etaye l'hypothese de la presence d'une zone de fixation unique probablement formee par la poche hydrophobe.

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Kumar, Pawan. "Studies of wire-matrix interaction in some tungsten wire reinforced stainless steels". Thesis, University of Canterbury. Mechanical Engineering, 2013. http://hdl.handle.net/10092/8980.

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There is potential for improving creep properties of stainless steels by reinforcing them with tungsten (W) wires. Past studies have shown that a detrimental factor that impairs the mechanical properties of tungsten wire reinforced superalloy composites is the formation of brittle intermetallic phases due to the interaction between W wire and constituents of the alloy matrices. Formation and growth of the intermetallic phases strongly depends on the matrix chemistry and for the retention of creep strength, matrix compositions that do not form intermetallic phases with tungsten are desirable for fabricating W wire reinforced composites for high temperature applications. This research investigated the formation and growth of reaction phases in W wire reinforced 316L (W/316L) stainless steel and HP alloy steel (W/HP) that were fabricated by casting method. Additionally, the effect of composition on the evolution and kinetics of reaction phases was studied in some W wire reinforced experimental alloys based on Fe-Ni-Cr only (W/Fe-Ni-Cr). The fabricated composites were diffusion annealed in the temperature range 1000-1200°C for 25-500 hours. Microstructure and chemistry of the reaction phases in the as-cast and diffusion annealed composites were studied using scanning electron microscopy, energy dispersive spectroscopy and electron backscattered diffraction techniques. Growth kinetics of the reaction layers and average effective interdiffusion coefficients in the layers were determined for the composites. Results showed that an intermetallic phase isostructural with µ-phase formed in the as-cast W/316L and W/Fe-Ni-Cr composites with 1 and 2 Fe:Ni matrix ratios. In W/HP a phase M12C with crystal structure similar to η-carbide was formed. These phases developed and formed brittle reaction layers around the W wires during diffusion annealing. A parabolic relationship between the µ-phase and η-carbide growth and diffusion annealing time indicated that the growth of reaction layers was diffusion controlled. In the W/Fe-Ni-Cr composites, formation of intermetallic phases did not occur in the matrices with 0.5Fe:Ni ratio, instead some isolated tungsten particles were observed in the matrix adjacent to the wires after diffusion annealing. In W/Fe-Ni-Cr composites with 1 and 2 Fe:Ni matrix ratio, the growth of µ-phase reaction layers during annealing was observed to be dependent on the matrix composition. It was found that with an increase in the Ni content in the matrix, growth of µ-phase reaction layer decreased. The study presented in this thesis gives first-hand information on phase formation and growth kinetics of the reaction layers in W/316L and W/HP composites. It revealed that the interaction of W with 316L and HP alloy matrices leads to formation of cracked intermetallic and carbide reaction layers which are not desirable in the composites designed for high temperature applications. It has also been shown in this study that in W/Fe-Ni-Cr composites, intermetallic phase formation can be suppressed by increasing Ni content in the matrix. In the composite with high Ni contents in the matrix (0.5Fe:Ni ratio) intermetallic phases do not form even after diffusion annealing at 1200°C. This intermetallic free W/Fe-Ni-Cr composite can further be studied for its creep strength.

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Barbosa, Christophe. "Experimental and numerical study of the interaction of a bubble with an inclined wall". Thesis, Toulouse, INPT, 2016. http://www.theses.fr/2016INPT0122.

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Cette thèse a pour objet l’étude de l’interaction d’une bulle à grand nombre de Reynolds et nombre de Weber moyen avec une paroi inclinée. Pour une combinaison bulle-liquide donnée, une augmentation de l’angle d’inclinaison de la paroi entraîne une transition de régime de mouvement de la bulle qui passe d’un régime de glissement à la paroi à un régime de rebonds périodiques. Un dispositif expérimental a été conçu et construit afin de produire la collision entre une bulle en condition d’ascension terminale et une paroi inclinée, l’angle d’inclinaison variant entre 5 et 80. Des campagnes de mesures ont été menées en utilisant de nombreux liquides et diamètres de bulles. La forme de la bulle de même que sa position ont été enregistrées, durant chaque expérience, avec une caméra rapide alors que le comportement du sillage a été observé grâce à la technique de Particule Image Vélocimétrie (PIV) à haute fréquence. En outre, le processus d’interaction a également été reproduit par simulation numérique. En utilisant l’équilibre des forces qui caractérise le mouvement de glissement à la paroi de la bulle, prenant en compte la nature visqueuse ou inertielle de la force de frottement, les mouvements de glissement à la paroi et de rebonds périodiques sont bien décrits et sont validés par les résultats expérimentaux. Le régime de glissement inertiel ainsi que le régime de rebond à la paroi sont associés à un nombre de Froude tangentiel constant. En ce qui concerne le régime de glissement visqueux, l’évolution du coefficient de frottement est reproduit de manière satisfaisante en prenant en compte les effets additifs de la présence d’un mur sur les écoulements potentiels et de la production de vorticité au niveau de la paroi. À partir de ce même équilibre des forces mais projeté suivant l’axe normal à la paroi, un ensemble de relations a été établi pour représenter la transition du régime de glissement à la paroi au régime de rebonds. La force de portance induite par les effets du sillage demeure d’importance majeure pour le critère de transition. Les différentes phases qui caractérisent la collision entre la bulle et la paroi inclinée sont analysées. Des modèles pour le coefficient de restitution normal et le coefficient de restitution tangentiel sont proposés et validés numériquement. Les simulations numériques reproduisent, entre autres, les différents aspects de la physique de l’interaction
The objective of the thesis is to study the interaction of a high Reynolds moderate Weber numberbubble with an inclined wall. For a given bubble-liquid combination, an increase of the inclinationangle results in a transition from a steady sliding motion to periodic bounces. An experimentaldevice was designed and built to generate the collision of bubbles in terminal state conditions withan inclined wall, with inclination angles ranging from 5 to 80. Experiments were conductedconsidering different liquid and bubble diameters. The bubble shape and position was recordedusing a high speed camera whereas the wake behavior was captured using a time resolved Particle Image Velocimetry technique. In addition, the interaction process was also studied using anumerical code. Considering a force balance on the sliding bubble, that takes into account theviscous or inertial nature of the drag force, the sliding and bouncing motions were wellcharacterized and validated by the experimental results. The inertial sliding and bouncing motionswere associated to a constant tangential Froude number. As for the viscous sliding motion, the corresponding drag coefficient was satisfactorily modelled through the additive effects of thepotential-flow wall effect and the vorticity production at the wall. Through the same force balance projected along the normal axis, a set of relations were obtained for the transition from sliding tobouncing motions. The wake induced lift force results to be of major importance for the transitioncriteria. The different phases that characterize the oblique collision were analyzed. Accordingly,the initial and final times for the process were chosen. On this basis, models for the normal and tangential coefficient of restitutions were proposed and numerically supported. The numericalsimulations reproduced the different aspect of the bubble inclined wall interaction

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Mouawad, Charbel. "Transfert de matière dans un système solide/liquide "ions/eau/pectine" : interactions, partage ionique et simulation par dynamique moléculaire". Thesis, Vandoeuvre-les-Nancy, INPL, 2007. http://www.theses.fr/2007INPL072N/document.

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Mass transfer intervening during the process of immersion influences the final composition of the product. These transfers primarily depend on the size of the immersed products, as well as temperature, the concentration and the nature of the solution of immersion. The main objective of this work is to study the mass transfer phenomena (water loss and solid gain) in solid/liquid system constituted of vegetable product (eggplant) immerged in salt solution. We determined the kinetic studies of eggplant in different salts solutions with two concentrations (saturation and 20%) at 3°C. The physicochemical properties of solution and salt such as molar concentration, molecular weight and ionic type affected the mechanism of water loss and solid gain. Knowledge about interaction ions/vegetable pectin is important for new product formulation. Determination of partition coefficient of ion in equilibrium system showed that the main physicochemical properties of ions and solution are ionic radius, electronegativity, ionic force and molar concentration. Mathematical predictive model was developed to predict the partition coefficient of ions in food/ solution system. Molecular dynamics simulations using a dynamic force field have been carried out to investigate the absorption of ions (K+, Na+, Ca2+, Mg2+, Cl-) in pectin/water/ion/aqueous solution system. Four systems were used. The results showed that the ionic type (cation and anion) influence the type and number of interactions between pectin-ion and water-ion and then offered an explicit description transfer phenomena and distribution of ions in the system solid/liquid
Les transferts de matière intervenant au cours du procédé d’immersion dépendent essentiellement de la taille des produits immergés, la température, la concentration et la nature de la solution d'immersion. L’objectif principal de ce travail porte sur l’étude des transferts dans un système solide/liquide constitué d’un produit végétal (aubergine) et d’une solution saline. Afin de parvenir à une bonne maîtrise de ces paramètres, les études cinétiques ont été conduites à 3°C sur des aubergines immergées dans des solutions salines avec deux concentrations. Les propriétés des solutions et des sels telles que la concentration molaire, la masse molaire et surtout la nature ionique influencent le mécanisme de perte et de gain. Les connaissances sur les interactions ions/pectines végétaux sont importants pour la formulation de nouveaux produits La détermination du coefficient de partage des ions à l’équilibre dans le système aubergine/solution ont montré que les principales propriétés des ions et des solutions influençant le coefficient de partage sont le rayon ionique, l’électronégativité, la force ionique et la concentration molaire. Un modèle mathématique a permis de prédire le coefficient de partage des ions dans ce système. Dans le but d’expliquer l’absorption des ions par la phase solide, une simulation par dynamique moléculaire a été menée sur un système pectine-eau-sels. Quatre systèmes ont été utilisés. Les résultats obtenus ont montré que la nature ionique influencent la nature et le nombre d’interaction entre pectine-ion et eau-ion et donc offrent une description explicite des phénomènes de transferts et distribution des ions dans le système solide/liquide

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Ozvenchuk, Vitalii [Verfasser], Elena [Akademischer Betreuer] Bratkovskaya i Marcus [Akademischer Betreuer] Bleicher. "Dynamical equilibration and transport coefficients of strongly interacting matter / Vitalii Ozvenchuk. Gutachter: Elena Bratkovskaya ; Marcus Bleicher. Betreuer: Elena Bratkovskaya". Frankfurt am Main : Univ.-Bibliothek Frankfurt am Main, 2013. http://d-nb.info/1043978216/34.

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Miller, Mark Stephen. "Use of osmotic coefficient measurements to validate and to correct the interaction thermodynamics of amino acids in molecular dynamics simulations". Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6476.

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Molecular dynamics simulations are an increasingly valuable tool to biochemical researchers: advances in computational power have expanded the range of biomolecules that can be simulated, and parameters describing these interactions are increasingly accurate. Despite substantial progress in force field parameterization, recent simulations of protein molecules using state-of-the-art, fixed-charge force fields revealed that the interactions among and within protein molecules can be too favorable, resulting in unrealistic aggregation or structural collapse of the proteins being simulated. To understand why these protein-protein interactions are so over-stabilized, I first assessed the ability of simulation force fields to represent accurately the interactions of individual amino acids, employing an osmotic pressure simulation apparatus that enabled direct comparison with experiment. Surprisingly, simulations of most of the amino acids resulted in behavior that was in strong agreement with experiment. A number of amino acids, however—notably those that contain hydroxyl groups and those that carry a formal charge—interacted in ways that were clearly inaccurate. Additionally, some commonly-used force fields failed to accurately represent the interactions of amino acids in a consistent manner. By further investigating the interactions of the functional groups of these amino acids, I was able not only to determine some of the root causes of individual amino acid inaccuracies, but also to implement simple modifications that brought the interactions of these small molecules and amino acids in stronger accord with experiment. These studies have highlighted some of the shortcomings in popular simulation force fields, and have proposed useful modifications to address them. Still, there is additional work that must be—and is being—conducted in order to correctly model the interaction behavior of proteins in simulation.

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Wang, Xianjie. "Interactions of ozone and acetic acid with natural Gobi dust". Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS412.

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Cette thèse de doctorat porte sur l’étude des interactions de l'ozone et de l'acide acétique avec des poussières minérales naturelles du désert de Gobi en Chine, à température ambiante, pression atmosphérique ainsi que dans des conditions sèches et humides. Les espèces en phase gazeuse et en phase adsorbée sont caractérisées par des techniques post-situ et in-situ. La capture de l’ozone par les poussières de Gobi est étudiée sur une large gamme de concentrations (20 ppb – 10 ppm) afin de clarifier les processus hétérogènes impliquant l'ozone et évaluer leurs implications en chimie atmosphérique et dans les procédés. Les poussières de Gobi présentent des propriétés catalytiques de décomposition de l'ozone avec un coefficient de capture stationnaire variant entre 2.6  10-9 et 6.2  10-8 selon la concentration d’ozone. Les molécules d'eau rivalisent avec l'ozone pour l’accès aux sites de surface, tandis que le traitement thermique à 150 °C peut régénérer de manière significative certains sites de surface après une exposition à l'ozone. Les modes d'interaction physisorptifs et chimisorptifs de l'acide acétique sur les poussières de Gobi sont ensuite étudiés: l’acide acétique s’adsorbe sous forme de monomère et dimère, ainsi que d'acétate bidentate. La quantité ainsi que la répartition des fractions réversibles et irréversibles d'acide acétique absorbées présentent des comportements différents entre conditions sèches et humides. Enfin, l'ozonation de l'acide acétique adsorbé sur les poussières de Gobi est étudiée pour évaluer l'aptitude de ce géo-matériau à être utilisé comme catalyseur d'intérêt
This PhD thesis investigates the interactions of ozone and acetic acid with a natural mineral dust from Gobi Desert in China, under room temperature, atmospheric pressure, dry and wet conditions, using post-situ and in-situ characterization techniques to address gas phase and adsorbed phase species. First, ozone uptake at the surface of Gobi dust is investigated over a large ozone concentration range (20 ppb – 10 ppm) to provide new insights on the heterogeneous processes of ozone with potential interest for both atmospheric chemistry and industrial frameworks. Gobi dust exhibits catalytic properties regarding ozone decomposition with a steady-state uptake coefficient ranging from 2.6  10-9 to 6.2  10-8 depending on ozone concentration. Water molecules compete with ozone for the same surface sites while thermal treatment at 150˚C can significantly regenerate the surface sites after surface exposure to ozone. Second, the physisorptive and chemisorptive interaction modes of acetic acid on Gobi dust have been studied evidencing the formation of molecularly adsorbed acetic acid in monomer and dimer forms as well as bidentate chelating acetate. The amount and the partition of reversibly and irreversibly adsorbed fractions of acetic acid taken up on Gobi dust exhibit contrasted behaviors under dry and 20% RH conditions. Finally, the oxidation of adsorbed acetic acid by ozone at the surface of Gobi dust is investigated to typify the ability of that geo-material to act as a catalyst of interest

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Pujol, Céline. "Hydrodynamique et brisure de symétrie chirale : application au gaz de pions et calcul de coefficients de transport". Phd thesis, Université Claude Bernard - Lyon I, 2003. http://tel.archives-ouvertes.fr/tel-00006288.

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Le cadre général dans lequel se situe cette thèse est l'étude des propriétés de la matière hadronique chaude et dense produite lors des collisions d'ions lourds ultrarelativistes. Cette matière chaude et dense est majoritairement constituée de pions, les particules les plus légères du monde hadronique. Leur faible masse provient de leur nature même : ce sont les bosons de Goldstone de la symétrie chirale. L'évolution du gaz de pions peut se faire, dès les premiers instants suivant sa formation, dans le cadre de l'hydrodynamique relativiste. Dans une première partie nous présentons l'hydrodynamique en présence de symétrie brisée en insistant particulièrement sur le fait que les modes de Goldstone sont à mettre sur un pied d'égalité avec les grandeurs conservées : à tous deux correspondent des modes hydrodynamiques. Nous montrons également comment ces nouveaux modes, caractéristiques de la brisure d'une symétrie, modifient les équations d'évolution. Partant de l'exemple d'un système superfluide, c'est-à-dire d'un système présentant une brisure de la symétrie U(1), nous présentons, dans la deuxième partie, les équations hydrodynamiques d'un fluide au sein duquel la symétrie chirale SU(2)$_L \times$ SU(2)$_R$ est brisée. Nous appliquons ensuite ces équations, d'une part aux collisions d'ions lourds ultrarelativistes dans le cadre du modèle de Bjorken, et d'autre part à la détermination des coefficients de transport. Enfin, la troisième partie est consacrée au calcul de la viscosité de cisaillement dans le cadre de modèles microscopiques de théorie des champs, à savoir les modèles $\lambda\phi^4$ et $\sigma$-non linéaire.

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Ghendrih, Philippe. "Effet du champ magnétique sur les interactions coulombienes dans un plasma chaud modification de l'équation cinétique et des coefficients de transport /". Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37605405d.

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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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Mery, Alain. "Mesure du coefficient de corrélation angulaire béta-neutrino dans la décroissance de l’6He à l’aide d’un piège de Paul". Caen, 2007. http://www.theses.fr/2007CAEN2018.

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Le thème central de ce travail est la mise en place et la caractérisation d’un piège de Paul utilisé pour la mesure du coefficient de corrélation angulaire électron-neutrino dans la décroissance de l’6He. Ce coefficient est sensible aux types d’interactions mis en jeu dans l’interaction faible. La valeur de ce coefficient peut être obtenue grâce à la distribution cinématique des évènements de décroissance. Un piège électromagnétique est utilisé pour confiner les ions 6He+ dans un petit volume de l’espace des phases. Sa géométrie ouverte permet la détection en coïncidence de l’électron et de l’ion de recul émis lors de la désintégration béta. Un dispositif de détection adapté est utilisé pour mesurer l’énergie de l’électron, le temps de vol de l’ion de recul et la position des deux particules pour chaque évènement. Une description globale de l’installation LPCTrap ainsi que de ses performances est présentée et montre que ce dispositif est apte à réaliser la mesure envisagée. En particulier, les caractéristiques du nuage d’ions piégés ont été obtenues par des simulations de type Monte Carlo et confrontées aux mesures expérimentales avec un bon accord. La première expérience a permis d’accumuler plus de 100 000 évènements en coïncidence. Une analyse préliminaire de ces résultats est exposée. Elle présente notamment une description des différentes observables accessibles ainsi qu’une comparaison entre le spectre de temps de vol expérimental et le spectre issu des simulations. Ces données vont permettre une mesure du coefficient de corrélation angulaire avec une erreur statistique inférieure à 2 %
The central topic of this work is the study of the properties and the implementation of a Paul trap used for the measurement of the beta-neutrino angular correlation parameter in the decay of 6He. This coefficient provides a signature of the nature of the interactions involved in the weak interaction. The value of this coefficient can be deduced from the kinematical distribution of the decay events. An electromagnetic trap is used for the trapping of 6He+ ions in a small volume. This trap has an open geometry that enables the detection in coincidence of the electron and the recoil ion emitted in the beta decay. A dedicated detection set up is used for the measurement of the electron energy, the ion time of flight and the position of the two particles for each event. A general description of the LPCTrap facility and of its performances is presented and shows that this set up is able to fulfill the proposed measurement. Especially, a comparison is made between the characteristics of the ion cloud obtained from Monte Carlo simulations and the experimental measurements with a good agreement. More than 100 000 coincident events have been recorded during the first experiment. A preliminary analysis of these results is shown. It includes a description of the different observables as well as a comparison between the experimental time of flight spectrum and the simulated spectrum. These data will allow a measurement of the angular correlation parameter with a statistical error smaller than 2 %

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Jiemchooroj, Auayporn. "First-principles calculations of long-range intermolecular dispersion forces". Licentiate thesis, Linköping : Dept. of Electrical Engineering, Linköping University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7512.

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Mouawad, Charbel Desobry Stéphane. "Transfert de matière dans un système solide/liquide "ions/eau/pectine" interactions, partage ionique et simulation par dynamique moléculaire /". S. l. : S. n, 2007. http://www.scd.inpl-nancy.fr/theses/2007_MOUAWAD_C.pdf.

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Salhani, Chloé. "Exploring thermoelectricity and electronic transport of molecular layers". Thesis, Université de Paris (2019-....), 2020. http://www.theses.fr/2020UNIP7013.

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Les progrès de la science des matériaux depuis les années 70 se sont engagés dans une course constante à la miniaturisation. Aux échelles où les effets quantiques dominent la physique en jeu, l'électronique moléculaire a été considérée comme un domaine d'étude prometteur, proposant d'exploiter la physique quantique pour atteindre la fonctionnalité souhaitée d'un dispositif moléculaire. Dans cette thèse, j'étudie les propriétés électroniques et thermoélectriques des jonctions moléculaires à l'état solide à grande surface, des dispositifs composés de couches moléculaires robustes et greffées par covalence formées de plusieurs chaînes moléculaires contenant plusieurs unités moléculaires en série, contactées par des électrodes métalliques. Une première partie de cette thèse consiste en l'étude des interactions inélastiques el-ph dans des couches d'anthraquinone (AQ). La molécule AQ présente des effets d'interférence quantique (QI), provoquant une extinction de la fonction de transmission (et donc de la conductance) près du point de polarisation nulle et améliorant ainsi la visibilité des effets inélastiques (interactions el-ph). La spectroscopie IETS est réalisée sur ces couches et permet d'identifier les modes vibratoires connus de la molécule AQ. Une deuxième partie de ces travaux concerne les propriétés thermoélectriques de couches moléculaires similaires (composés de couches moléculaires d’AQ, de BTB et de NB). Les défis d'ingénierie sont relevés avec le développement d'une nouvelle géométrie d'échantillon utilisant un alliage à couche mince AuGe comme élément chauffant thermomètre, pour permettre d'établir un gradient de température contrôlé à travers l'épaisseur de la couche moléculaire (~ 15 nm). Enfin, j'explore la présence d'un potentiel thermoélectrique développé à travers la couche moléculaire. Une troisième et dernière partie de cette thèse explore une nouvelle géométrie pour les jonctions moléculaires de grande surface. Au lieu d'une approche ascendante, des nanotrenches sont utilisées pour fabriquer des jonctions moléculaires dans le plan dans une géométrie conçue pour permettre l'intégration de la porte à un stade ultérieur. Je présente la fabrication de ces nanotranches en utilisant une méthode de masque de bord d'ombre, et leur caractérisation avant et après greffe moléculaire. Les nanotranches greffées AQ révèlent des signatures de transport typiques des jonctions moléculaires qui sont comparées au comportement de la fabrication planaire plus standard
Progress in material science over the past half-century has been engaged in a constant race towards miniaturization. At the scales where quantum effects dominate the physics at play, molecular electronics has been considered a promising field of study, proposing to exploit quantum physics to achieve the desired functionality of a molecular device. In this thesis, I investigate electronic and thermoelectric properties of large-area solid-state molecular junctions, devices constructed of robust and covalently-grafted molecular layers formed by multiple molecular chains containing several molecular units in series contacted between metallic electrodes. A first part of this thesis concerns the investigation of inelastic el-ph interactions in layers of anthraquinone (AQ). The AQ molecule exhibits quantum interference (QI) effects, causing an extinction of the transmission function (and thus the conductance) near the zero-bias point and thus enhancing the visibility of inelastic effects (el-ph interactions). IETS spectroscopy is performed on these layers and allows to identify known vibrational modes of the AQ molecule. A second part of this work investigates the thermoelectric properties of similar molecular layers (using AQ, BTB and NB molecules). Engineering challenges are met with the development of a new sample geometry using an AuGe thin-film alloy as a heater-thermometer element, to enable establishing a controlled temperature gradient across the thickness of the molecular layer (~15nm). Finally, I explore the presence of a thermoelectric potential developed across the molecular layer. A third and final part of this thesis explores a new geometry for large area molecular junctions. Instead of a bottom-up approach, nanotrenches are used to fabricate in-plane molecular junctions in a geometry designed to allow gate integration at a later stage. I present the fabrication of these nanotrenches using a shadow-edge mask method, and their characterization before and after molecular grafting. AQ-grafted nanotrenches reveal typical transport signatures of molecular junctions that are compared to the behavior of the more standard planar fabrication

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Lindgren, Kristina. "The Behaviour of the Latent Heat Exchange Coefficient in the Stable Marine Boundary Layer". Thesis, Uppsala University, Department of Earth Sciences, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-9140.

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Knowledge of the turbulent fluxes at the sea surface is important for understanding the interaction between atmosphere and ocean. With better knowledge, improvements in the estimation of the heat exchange coefficients can be made and hence models are able to predict the weather and future climate with higher accuracy.

The exchange coefficients of latent and sensible heat during stable stratification vary in the literature. Therefore it is necessary to investigate the processes influencing the air-sea exchange of water vapour and heat in order to estimate these values. With measurements from a tower and a directional waverider buoy at the site Östergarnsholm in the Baltic Sea, data used in this study have been sampled from the years 2005-2007. This site represents open-ocean conditions during most situations when the wind comes from the south-east sector. The neutral exchange coefficients, CEN and CHN, have been calculated along with the non-dimensional profile functions for temperature and wind to study the dependence of stability and other parameters of relevance.

It was found that CEN increased slightly with wind speed and reached a mean value of approximately 1.45×10-3. The highest values of CEN were observed during near neutral conditions and low wave ages. CHN attained a mean value of approximately 0.77×10-3 and did not show any relation to wind speed or to wave age. No significant dependence with wind or wave direction could be shown for either CEN or CHN in the sector 80-220°. The stability correction, performed to reduce the dependence on stratification for CEN and CHN, was well performed for stabilities higher than 0.15. The stability is represented by a relationship between the height and the Obukhov-length (z/L).

Validity of the non-dimensional profile functions for temperature and wind showed that, for smaller stabilities, these functions gave higher values than the corresponding functions recommended by Högström (1996). The profile funtions for temperature was shown to have a larger scatter while the profile functions for wind was less scattered and deviated more from the functions given by Högström

Kunskap om turbulenta flöden i det marina gränsskiktet är viktigt för att förstå växelverkan mellan atmosfär och hav. Med bättre kunskap kan förbättringar i bestämningen av utbyteskoefficienterna för latent och sensibelt värme erhållas. Det medför att modeller kan prognostisera väder och framtida klimat med högre noggrannhet.

Utbyteskoefficienterna för latent och sensibelt värme har för stabil skiktning olika värden i litteraturen. Detta gör det nödvändigt att undersöka de processer som påverkar utbytet av vattenånga och värme mellan luft och hav för att kunna bestämma dessa värden. Data som har använts i den här studien insamlades mellan år 2005 och 2007 från en boj och ett torn vid mätplatsen Östergarnsholm i Baltiska havet. För det flesta situationer, när vinden blåser från syd-ost, representerar mätplatsen ett förhållande likvärdigt det över öppet hav. De neutrala utbyteskoefficienterna, CEN och CHN, och de dimensionslösa profilfunktionera för temperatur och vind, och , har beräknats för att studera beroendet av stabilitet samt andra relevanta parametrar.

Beräkningarna visade att CEN ökade något med vindhastighet och hamnade på ett medelvärde av ungefär 1.45×10-3. De högsta värdena på CEN observerades vid nära neutrala förhållanden och låga vågåldrar. CHN uppmättes till att ha ett medelvärde på ungefär 0.77×10-3 och uppvisade inget beroende med vindhastighet eller vågålder. Inget märkbart beroende med vind- eller vågriktning kunde visas för CEN eller CHN i sektorn 80-220°. Stabilitetskorrektionen, utförd för att reducera beroendet av atmosfärens skiktning för CEN och CHN, var bra för stabiliteter högre än 0.15. Stabiliteten representeras av förhållandet mellan höjden och Obukhov-längden (z/L).

Utvärdering av de dimensionslösa funktionerna för temperatur och vind visade att dessa funktioner, för små stabiliteter, gav högre värden än motsvarande funktioner som rekommenderas av Högström (1996). Värdena på profilfunktionerna för temperatur hade större spridning än värdena på profilfunktionerna för vind och avvek mer från funktionerna givna av Högström.

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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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Shaghaghi, Tahereh. "FEM and XFEM approaches to Investigate the Hydromechanical Interactions within a jointed soft-rock slope". Thesis, Federation University Australia, 2020. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/177426.

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One of the most significant challenges of open-cut mining is to provide stability for the excavated slopes. Unrealistic predictions of the slopes’ behaviour during and after mining operations can lead to the failure of slopes, and this may pose a threat to human lives, the economy, and the environment. By excavating soft rock masses in open-cut mines, pre-existing joints can open and new joints can form behind excavated slopes. This phenomenon is due to the geotechnical character of the materials and stress relief movements of the excavated slopes. The stability of slopes in the rock masses is significantly influenced by the existence of discontinuities such as joints. The water flows in the opened joints can change the pore water pressure distribution in the slopes. The interaction between the joints and the water may impose different loading scenarios on the open-cut mines and put the safety of mining operations at risk. The analysis of slope stability can become more complicated because of the presence of water, discontinuities, and their interaction within the slopes in open-cut mines. This study investigates the hydromechanical interactions in the saturated jointed slopes due to pore water pressure changes. The second-largest open-cut mine in Australia, the Yallourn brown coal open-cut mine located in Victoria, was chosen as the case study for this research. In this study, several coupled pore fluid diffusion and stress-strain analyses are conducted using the extended finite element method (XFEM) in conjunction with the finite element method (FEM). This study firstly examines a joint aperture and pore water pressure changes of the excavated jointed slope due to installing a drainage system and backfilling in front of the slope. Secondly, a series of sensitivity analyses are carried out on the pore water pressure distribution changes to the variation of the permeability magnitude of the material and leakage properties of the joint surfaces. Finally, to control the pore water pressure of the saturated jointed slope, a series of drainage systems is designed. The arrangement and length of the drains are optimised by conducting a series of sensitivity analyses on the leakage properties of the joint and the permeability of the soft rock.
Doctor of Philosophy

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