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Tesi sul tema "Thermodynamics"
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1
Popovic, Marko. "Application of the Entropy Concept to Thermodynamics and Life Sciences: Evolution Parallels Thermodynamics, Cellulose Hydrolysis Thermodynamics, and Ordered and Disordered Vacancies Thermodynamics". BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/6996.
Testo completoAbstract (sommario):
Entropy, first introduced in thermodynamics, is used in a wide range of fields. Chapter 1 discusses some important theoretical and practical aspects of entropy: what is entropy, is it subjective or objective, and how to properly apply it to living organisms. Chapter 2 presents applications of entropy to evolution. Chapter 3 shows how cellulosic biofuel production can be improved. Chapter 4 shows how lattice vacancies influence the thermodynamic properties of materials. To determine the nature of thermodynamic entropy, Chapters 1 and 2 describe the roots, the conceptual history of entropy, as well as its path of development and application. From the viewpoint of physics, thermal entropy is a measure of useless energy stored in a system resulting from thermal motion of particles. Thermal entropy is a non-negative objective property. The negentropy concept, while mathematically correct, is physically misleading. This dissertation hypothesizes that concepts from thermodynamics and statistical mechanics can be used to define statistical measurements, similar to thermodynamic entropy, to summarize the convergence of processes driven by random inputs subject to deterministic constraints. A primary example discussed here is evolution in biological systems. As discussed in this dissertation, the first and second laws of thermodynamics do not translate directly into parallel laws for the biome. But, the fundamental principles on which thermodynamic entropy is based are also true for information. Based on these principles, it is shown that adaptation and evolution are stochastically deterministic. Chapter 3 discusses the hydrolysis of cellulose to glucose, which is a key reaction in renewable energy from biomass and in mineralization of soil organic matter to CO2. Conditional thermodynamic parameters, ΔhydG', ΔhydH', and ΔhydS', and equilibrium glucose concentrations are reported for the reaction C6H10O5(cellulose) + H2O(l) ⇄ C6H12O6(aq) as functions of temperature from 0 to 100°C. Activity coefficients of aqueous glucose solution were determined as a function of temperature. The results suggest that producing cellulosic biofuels at higher temperatures will result in higher conversion. Chapter 4 presents the data and a theory relating the linear term in the low temperature heat capacity to lattice vacancy concentration. The theory gives a quantitative result for disordered vacancies, but overestimates the contribution from ordered vacancies because ordering leads to a decreased influence of vacancies on heat capacity.
2
De, Lucca Brenno Jason Sanzio Peter. "Linear irreversible thermodynamics". Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20975/.
Testo completoAbstract (sommario):
In questa tesi tratteremo il problema di costruire una teoria termodinamica per trasformazioni su un sistema passante per stati di non-equilibrio. Cercando di generalizzare a sistemi che non sono all’equilibrio, rilasseremo la richiesta che siano in equilibrio globalmente. Lo stato termodinamico sarà univocamente determinato da un insieme di parametri termodinamici definiti localmente, della stessa natura e significato fisico dei parametri usati nella termodinamica classica. Le molteplici assunzioni necessarie al fine di avere una teoria mesoscopica comunque predittiva verranno giustificate a posteriori, quando possibile, in base alle predizioni che da tale modello nasceranno. In particolare ci concentreremo sugli effetti termoelettrici di Thompson, Seebeck e Peltier, esempi storici di grande rilevanza nel campo della termodinamica del non-equilibrio.
3
Langbein, Rollo Foster. "Thermodynamics and inflation". Thesis, Durham University, 1992. http://etheses.dur.ac.uk/5622/.
Testo completoAbstract (sommario):
The standard model of particle physics is introduced, and extensions of it, which may be of cosmological relevance, are considered. The inflationary paradigm is reviewed as an extension of the standard cosmological model. In particular, the natural inflation mechanism resulting from a thermal phase change in a field theory with a spontaneous symmetry breaking potential, is examined. The question of when thermal equilibrium is likely to be a valid assumption in the early universe is considered in some detail. For inflation models, this question is answered by a self-consistency argument involving the total number of interactions per inflaton particle. In order to describe thermal-phase-change inflation models further, the temperature-dependent effective potential resulting from finite-temperature field theory is reviewed. The self-consistency test is developed into a numerical procedure which may be used to discuss the likelihood of thermal state generation in specific inflation models in a quantitative way. Alternatively, the method can be used to provide bounds on the parameters in the inflation potential from the requirement that a thermal state should occur. This procedure is applied to several example potentials and in particular it is easily verified that the "new inflation" model (relying on a phase change) is not viable. The method is quite general and can be applied to any inflation model for which a finite temperature effective potential can be defined. The procedure is generalised to the recently proposed extended inflation. Bounds on the extra free parameters which must be introduced in extended inflation are discussed. It is concluded that despite these extra free parameters the difficulties of generating a thermal state are just as great as they are in conventional inflation.
4
Matschei, Thomas. "Thermodynamics of cement hydration". Thesis, University of Aberdeen, 2007. http://library.eawag-empa.ch/empa_publications_2007_open_access/EMPA20070485.pdf.
Testo completo
5
Perarnau, Llobet Martí. "Thermodynamics and quantum correlations". Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/404732.
Testo completoAbstract (sommario):
Thermodynamics traditionally deals with macroscopic systems at thermal equilibrium. However, since the very beginning of the theory, its range of applicability has only increased, nowadays being applied to virtually every field of science, and to systems of extremely different size.
This thesis is devoted to the study of thermodynamics in the quantum regime. It contains original results on topics that include: Work extraction from quantum systems, fluctuations of work, the energetic value of correlations and entanglement, and the thermodynamics of closed quantum many body systems.
First, we study work extraction from thermally isolated systems. Here the notion of passive states naturally arises, as those quantum states from which no work can be extracted. We start by characterising the set of passive states, and find the most energetic passive states, a dual family to the well known Gibbs (or thermal) states. Remarkably, passive states have the property of activation: When considered as a whole, several copies of passive states can become nonpassive. We study the dynamics of activation processes, and find a relation between the entanglement generated and the speed of the process.
Next, we consider the possibility of extracting work from a system using an auxiliary thermal bath. In this case, according to the second law of thermodynamics, the amount of work is bounded by the free energy difference.
We develop corrections to this law which arise from the finite size and the structure of the bath.
We go on by studying the fluctuations of work. Fluctuations are particularly relevant for small systems, where their relative size is comparable to the average value itself. However, characterising the fluctuations in the quantum regime is particularly difficult, as measurements generically disturb the state. In fact, we derive a no go result, showing that it is not possible to exactly measure the fluctuations of work in quantum coherent processes. Despite this result, we develop a new scheme that allows for their approximate measurement.
An important part of this thesis is devoted to the relation between quantum correlations and work. We start by considering a set of correlated states which are thermal at the local level, in which case the extractable work can only come from the correlations. We compute the amount of work that can be stored in entangled, separable and correlated states with a fixed entropy, by finding the corresponding optimal states and protocols. These results provide fundamental bounds on the potential of different type of correlations for work storage and extraction. Next, we consider the converse scenario, and study the creation of correlations from thermal states. We find thresholds on the maximal temperature for the generation of entanglement. We also work out the minimal work cost of creating different types of correlations, including total correlations, entanglement, and genuine multipartite entanglement.
Finally, we study the thermodynamics of closed quantum systems. Here we use one of the most important recent insights from the study of equilibration in quantum systems: Closed many body systems do not equilibrate, but can be effectively described as if they had equilibrated when looking at a restricted, physically relevant, class of observables. Importantly, the corresponding equilibrium state is not necessarily a Gibbs state, but may be very well given by a Generalized Gibbs ensemble state. With this in mind, we develop a framework for studying entropy production and work extraction in closed quantum systems.La termodinàmica va néixer com una teoria dedicada a l'estudi de cossos macroscòpics en equilibri tèrmic. A partir d'aquell moment, l'abast de la teoria no ha deixat d'augmentar, aplicant-se en l'actualitat a gran part de les disciplines científiques, així com a objectes de mides extremadament diferents. La present tesis està dedicada a l'estudi de la termodinàmica de sistemes quàntics. Conté resultats originals en diferents temes, que inclouen l'extracció de treball de sistemes quàntics, les fluctuacions de treball, la relació entre l'energia i les correlacions quàntiques, i la termodinàmica de sistemes de molts cossos. La primera part de la tesis està dedicada a l'estudi de l'extracció de treball de sistemes quàntics. En aquest context la noció d'estat passiu (un estat del qual no es pot extreure treball) és fonamental. Primer de tot, caracteritzem el conjunt d'estats passius, i en particular trobem els més energètics, que es troben a l'altre extrem dels estats tèrmics (o de Gibbs). Notablement, els estats passius poden ser activats, en el sentit que es pot extreure treball d'un conjunt suficientment gran de còpies d'un estat passiu. Estudiant en detall l'esmentat procés d'activació, trobem una relació entre la velocitat del procés i l'entrellaçament generat. Seguidament, considerem la possibilitat d'extreure treball d'un sistema utilitzant un bany tèrmic. En aquest cas, d'acord amb la segona llei de la termodinàmica, la quantitat de treball està limitada per l'energia lliure. Per sistemes quàntics, en molts casos no és possible extreure tota l'energia lliure, i desenvolupem correccions de la segona llei que depenen només de la mida del bany i de la seva estructura. A continuació estudiem les fluctuacions termodinàmiques (en particular del treball), que són especialment rellevants per sistemes microscòpics. La seva descripció en el règim quàntic és especialment difícil, donat que les mesures tenen un efecte invasiu en l'estat. De fet, mostrem que és impossible mesurar exactament les fluctuacions d'energia en processos que involucren coherència quàntica. Malgrat aquest resultat, també desenvolupem un sistema per mesurar les fluctuacions del treball de forma aproximada. Una part important d'aquesta tesis està dedicada a la relació entre les correlacions (quàntiques) i el treball. Comencem considerant un conjunt d'estats correlacionats, que individualment es troben en un estat tèrmic. La motivació és que en aquest cas el treball contingut en els estats prové únicament de les correlacions. En aquest escenari, calculem la quantitat de treball que es pot extreure d'estats entrellaçats, estats separables i estats correlacionats amb una determinada entropia. És a dir, calculem el treball màxim que es pot extreure de les correlacions, tan clàssiques com quàntiques. A continuació, considerem el procés invers, és a dir, la creació de correlacions en estats tèrmics. En aquest cas derivem límits en la temperatura màxima per poder crear diferents tipus entrellaçament, i el corresponent cost energètic. Finalment, estudiem la termodinàmica de sistemes de molts cossos. Aquí fem servir un dels resultats més importants relacionats amb l'equilibració en sistemes quàntics: sistemes quàntics tancats que involucren moltes partícules no arriben a l'equilibri, però es comporten com si hi haguessin arribat per la majoria d'observables (incloent observables rellevants des d'un punt de vista físic com l'energia). Tanmateix, el corresponent estat d'equilibri no és sempre tèrmic, i a vegades només es pot descriure mitjançant un estat generalitzat de Gibbs (GGE). La nostra contribució consisteix en desenvolupar un formalisme que permet estudiar la producció d'entropia i l'extracció del treball en estats GGE, el qual apliquem a sistemes de fermions.
6
Bakk, Audun. "Statistical Thermodynamics of Proteins". Doctoral thesis, Norwegian University of Science and Technology, Department of Physics, 2002. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-494.
Testo completoAbstract (sommario):
The subject of this thesis is to formulate effective energy expressions (Hamiltonians) of proteins and protein related systems. By use of equilibrium statistical mechanics we calculate thermodynamical functions, whereupon we compare the results from theory with experimental data. Papers 1-7 and 10-12 concern this problem. In addition, Paper 8 (P8) and Paper 9 (P9) are attached. Both these papers were finalized during the Ph.D. study. However, they are not related to proteins.
Papers II, III, V, VII, VIII, XI and XII are reprinted with kind permission of Elsevier, sciencedirect.com Papers VI and IX are reprinted with kind permission of the American Physical Society.
7
Erickson, Kristy M., e University of Lethbridge Faculty of Arts and Science. "Thermodynamics of aqueous solutions". Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2007. http://hdl.handle.net/10133/529.
Testo completoAbstract (sommario):
Relative densities and relative massic heat capacities have been measured for aqueous solutions of triflic acid (CF3SO3H), sodium triflate (NaCF3SO3), gadolinium triflate (Gd(CF3SO3)3), dysprosium triflate (Dy(CF3SO3)3), neodymium triflate (Nd(CF3SO3)3), erbium triflate (Er(CF3SO3)3), ytterbium triflate (Yb(CF3SO3)3), and yttrium triflate (Y(CF3SO3)3) at T = (288.15, 298.15, 313.15, and 328.15) K and
p = 0.1 MPa. The resulting densities and massic heat capacities have been used to calculate out apparent molar volume and apparent molar heat capacity data for each of the investigated aqueous systems. The concentration dependencies of the apparent molar volumes and apparent molar heat capacities have been modeled using Pitzer-ion interaction equations. Single ion volumes and heat capacities have been calculated using estimates of the apparent molar properties at infinite dilution obtained from the Pitzer-ion interaction equations. These single ion values have, where possible, been compared with those previously reported in the literature.
Also, relative densities have been measured for aqueous solutions of CF3SO3H, Gd(CF3SO3)3, Nd(CF3SO3)3, and Yb(CF3SO3)3 at T = (323.15, 348.15, 373.15, and 423.15) K and p = (5.00, 10.00, and 15.00) MPa. The resulting densities have been used to calculate apparent molar volumes. The concentration dependences of these properties have also been modeled using Pitzer-ion interaction equations. The apparent molar volumes have been used to calculate single ion volumes which, in turn, have been compared with those previously reported in the literature.
This thesis also attempts to model the temperature, pressure, and concentration dependencies of the reported apparent molar properties of each system investigated using an equation of state commonly referred to as the density model. Where possible, the results of this model have been compared with those results from models previously reported in the literature.xiv, 148 leaves ; 29 cm.
8
Manda, Dimitra. "Thermodynamics of polymer blends". Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300415.
Testo completo
9
Guedens, Raf Maurice Elvire. "Thermodynamics of gravitating systems". Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619992.
Testo completo
10
Weiguo, Shen. "Thermodynamics of alkane solutions". Thesis, University of Canterbury. Chemical and Process Engineering, 1988. http://hdl.handle.net/10092/7727.
Testo completoAbstract (sommario):
An apparatus for static vapour pressure measurements on pure liquids and on binary and ternary mixtures containing one involatile component has been designed and constructed. The apparatus and corresponding experimental techniques have been tested and experimental errors have been discussed.
Measurements have been made of the vapour pressures of binary mixtures of n-hexane + n-hexadecane at 298.15 K and 303.15 K and of binary mixtures of n-hexane + n-octane, n-octane + n-hexadecane, and ternary mixtures of n-hexane + n-octane + n-hexadecane at 298.15 K.
The experimental measurements of pressures (P) vs mole fractions (x) have been fitted to the Redlich-Kister equation by Barker's method to obtain activity coefficients of each component in the liquid phase, the excess Gibbs functions, and the mole fractions in the vapour phase.
The results for n-hexane + n-hexadecane at 303.15 K have been compared with those of previous work (Williamson, 1957) and the agreement is reasonably good.
The excess volumes of n-hexane +benzene, n-dodecane + 2-methylpentane and pseudo n-dodecane prepared from equimolar numbers of n-decane + n-tetradecane + each of four branched hexane isomers at 298.15 K have been obtained from measurements of the densities of pure compounds and mixtures with a vibrating tube densimeter. Two methods for preparation of mixtures of which densities are required to be accurately measured have been designed and compared with each other.
The excess enthalpies of 2-methylpentane with n-dodecane and with each of three pseudo n-dodecanes prepared from equimolar mixtures of n-decane + n-tetradecane, n-undecane + n-tridecane, and n-octane + n-hexadecane, and the excess enthalpies of equimolar decane + tetradecane mixture with each of the other three branched hexane isomers at 298.15 K have been measured with an isothermal displacement calorimeter.
The experimental results of binary mixtures have been discussed in term of the principle of congruence with Hijmans' graphical method and Bellemans and Mat's analytical formula. New graphical tests of the principle of congruence and a modified Bellemans and Mat equation for ternary mixtures have been developed and applied to the experimental p-x data of ternary systems. The agreement between the experimental values and those predicted by the principle are excellent. The modified Bellemans and Mat equation seems to be more powerful than and preferable to the Redlich-Kister equation for the systems investigated in this work.
11
MacDonald, Robin John. "Thermodynamics of polymer mixtures". Thesis, Durham University, 1991. http://etheses.dur.ac.uk/6096/.
Testo completoAbstract (sommario):
Research into the thermodynamic behaviour of copolymer blends has been stimulated by the increasing number of applications in which these materials can be used. In this work, it was intended to characterise the thermodynamics of mixtures of two industrial copolymers and to review the experimental techniques and theoretical analyses currently used in this field. The copolymers used were poly(ethylene - co-vinyl acetate), with Mn = 3290, and poly(tetradecyl fumarate - co - vinyl acetate), with Mn = 10400. The thermodynamics of these mixtures was studied using Differential Scanning Calorimetry, Inverse Phase Gas Chromatography. Solvent Vapour Sorption, Heats of Mixing Calorimetry and Phase Contrast Optical Microscopy. The results of these experiments were interpreted using Flory-Huggins Lattice fluid theory and Flory-Prigogine equation of state theory. Additionally, the results of the calorimetry and chromatography experiments were used to predict the theoretical phase boundary with the intention of comparing the phase boundaries determined experimentally with those predicted theoretically. Unfortunately this comparison could not be made because none of the techniques listed above located a miscibility limit between 303 and 393K. Although some of the experimental results are in conflict, it has been concluded that these materials are immiscible in all proportions in this temperature range. The theoretically simulated spinodal condition occurs between 5 and 50K and is of little practical use in the absence of its experimental equivalent and its extreme temperature. The free energy change which occurs on mixing these copolymers is dominated by the entropic contribution and the equation of state was concluded to be inadequate to interpret this type of behaviour. It is believed that this is the first work which uses experimental data and a partition function to calculate directly a phase boundary without the inclusion of a fixing parameter.
12
Driver, Gordon William. "Thermodynamics of ionic liquids". Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.479423.
Testo completo
13
Peppin, Stephen Stuart Lyman. "Thermodynamics of multiphase systems". Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614891.
Testo completo
14
Mascie-Taylor, Jonathan Hugo. "The thermodynamics of risk". Thesis, University of Warwick, 2014. http://wrap.warwick.ac.uk/66910/.
Testo completoAbstract (sommario):
It is now routine to consider the full probability distribution of downturns in many sectors. In the financial services sector regulators (both internal and external) require corporations not only to measure their risk, but also to hold a sufficient amount of capital to cover potential losses given that risk. Another example is in emergency service vehicle routing, where one needs to be able to reliably get to a destination within a fixed limit of time, rather than taking a route which may have a shorter expected travel time but could, under certain travel conditions, take significantly longer [Samaranayake et al., 2012]. Further examples can be found in food hygiene [Pouillot et al., 2007] and technology infrastructure [Buyya et al., 2009]. In the first part of the thesis we consider the implications of risk in portfolio optimisation. We construct an algorithm which allows for the efficient optimisation of a portfolio at various risk points. During this work we assume that the value at risk can only be estimated via sampling; this is because it would be near impossible to analytically capture the probability distribution of a large portfolio. We focus initially on optimising a single risk point but later expand the work to the optimisation of multiple risk points. We study the ensemble defined by the algorithm, and also various approximations of it are then used to both improve the algorithm but also to question exactly what we should be optimising when we wish to minimise risk. The key challenge in constructing such an algorithm is to consider how much the optimisation method biases the samples used to estimate the value at risk. We wish to select genuinely better solutions; not just solutions which were somehow lucky, and hence treated more favourably, during the optimisation process. In the second part of the thesis we switch our focus to considering how we can understand when large losses will occur. In the financial services sector this translates to asking the question: under what market conditions will I make a (very) significant loss, or even go bankrupt? We consider various methods of answering this question. The initial algorithm relies heavily on an understanding of how our portfolio is modelled but we work to extend this algorithm so that no prior knowledge of the system is required. In the final chapter we discuss some further implications and possible future directions of this work.
15
Lopez-Monsalvo, Cesar Simon. "Covariant thermodynamics & relativity". Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/197299/.
Testo completoAbstract (sommario):
This thesis deals with the dynamics of irreversible processes within the context of the general theory of relativity. In particular, we address the problem of the `infinite' speed of propagation of thermal disturbances in a dissipative fluid. Although this problem is not new, its best known solution - the Israel and Stewart second order expansion - has an effective, rather than fundamental, character. The present work builds on the multi-fluid variational approach to relativistic dissipation, pioneered by Carter, and provides a dynamical theory of heat conduction. The novel property of such approach is the thermodynamic interpretation associated with a two-fluid system whose constituents are matter and entropy. The dynamics of this model leads to a relativistic generalisation of the Cattaneo equation; the constitutive relation for causal heat transport. A comparison with the Israel and Stewart model is presented and its equivalence is shown. This discussion provides new insights into the not-well understood definition of a non-equilibrium temperature. A crucial feature of the multi-fluid approach is the interaction between its constituents. It is a well known fact that when two, or more, fluids interact, instabilities may occur. Within this work, the two-stream instability analysis is extended to the relativistic domain. As far as the author is aware, such extension has not been discussed in the literature. The analysis allows to assess the stability and causality of relativistic models of matter and their linear deviations from thermodynamic equilibrium directly from their equations of state or, equivalently, their Lagrangian densities. For completeness, a brief digression on a consistent (stable and causal) `first-order' model is also included. Finally, the road to follow is laid by posing some physical applications together with some future perspectives and closing remarks. To sum up, the variational approach to heat conduction presented in this thesis constitutes a mathematically promising formalism to explore the relativistic evolution towards equilibrium of dissipative fluids in a dynamical manner and to get a deeper conceptual understanding of non-equilibrium thermodynamic quantities. Moreover, it might also be useful to explore the more fundamental issues of the irreversible dynamics of relativity and its connections with the time asymmetry of nature
16
Khadse, Anil N. "Thermodynamics of polyelectrolyte solutions". Thesis, IIT Bombay, Mumbai, 2003. http://hdl.handle.net/10919/71547.
Testo completoAbstract (sommario):
Polymers having many ionizable groups in their molecular structure are called Polyelectrolytes. They are extensively used in industries like papermaking, food processing, medicine and pharmaceuticals, water purification, oil field exploration, cosmetic formulation etc. In spite of wide applicability its current status of knowledge is precursory due complexity of their behavior in solution as well as at interface. Solution properties of polyelectrolytes are extensively studied in last 40 years to understand their behavior. The activity is important thermodynamic property. From activity we can get most of thermodynamic properties like interaction parameter, free energy of dilution of the polyelectrolyte, degree of dissociation of polyelectrolytes etc.Several models of Polyelectrolytes thermodynamics have been proposed. Two general approaches have been used to model Polyelectrolytes thermodynamics, spherical and cylindrical (chain) models. Two of the successful models to explain and predict commonly measured properties of polyelectrolytes such as osmotic coefficient and counterion activity coefficients have been proposed by Manning and Oosawa. Most of these models are applicable at infinite dilution only may be due to weak inter chain interactions. An Excess Gibb’s free energy model can predict properties at finite concentrations of polyelectrolytes, which is combination of Manning model and Local composition model.Vapor pressure osmometry and isothermal Titration Microcalorimetry are experimental methods to determine the thermodynamic properties of polymer solvent system. Osmometry helps to understand the thermodynamics of polymer solutions as it determines the value of osmotic pressure, which in turn gives the value of thermodynamic parameters. Isothermal Titration Microcalorimetry gives the heat of dilution directly from which we can calculate activity of the solution.The osmotic coefficient and activity of water in aqueous NaPSS solution are found out using Vapor pressure osmometry and Isothermal titration calorimeter at different temperatures. The results are compared with result obtained by an excess Gibb’s free energy model. Measured data show good agreement with available literature data at that temperature.
17
Steele-MacInnis, Matthew. "Thermodynamics of geologic fluids". Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/22026.
Testo completoAbstract (sommario):
Fluids play a vital role in essentially all geologic environments and processes, and are the principal media of heat and mass transfer in the Earth. The properties of geologic fluids can be diverse, as fluids occur at conditions ranging from ambient temperatures and pressures at Earth's surface, to extreme temperatures and pressures in Earth's deep interior. Regardless the wide ranges of conditions at which geologic fluids occur, fluid properties are described and governed by the same fundamental thermodynamic relationships. Thus, application of thermodynamic principles and methods allows us to decipher the properties and roles of geologic fluids, to help understand geologic processes.
Fluid inclusions in minerals provide one of the best available tools to study the compositions of geological fluids. Compositions of fluid inclusions can be determined from microthermometric measurements, based on the vapor-saturated liquidus conditions of model chemical systems, or by various microanalytical techniques. The vaporsaturated liquidus relations of the system H2O-NaCl-CaCl2 have been modeled to allow estimation of fluid inclusion compositions by either microthermometric or microanalytical methods.
Carbon capture and storage (CCS) in deep saline formations represents one option for reducing anthropogenic CO2 emissions into Earth's atmosphere. Availability of storage volume in deep saline formations is a significant component of injection and storage planning. Investigation of the volumetric properties of CO2, brine and CO2-saturated brine reveals that storage volume requirements are minimized when CO2 dissolves into brine. These results suggest that a protocol involving brine extraction, CO2 dissolution and re-injection may optimize CCS in deep saline formations.
Numerical modeling of quartz dissolution and precipitation in a sub-seafloor hydrothermal system was used to understand the role of fluid-phase immiscibility ("boiling") on quartz-fluid interactions, and to predict where in the system quartz could deposit and trap fluid inclusions. The spatial distribution of zones of quartz dissolution and precipitation is complex, owing to the many inter-related factors controlling quartz solubility. Immiscibility exerts a strong control over the occurrence of quartz precipitation in the deeper regions of fluid circulation.Ph. D.
18
Solis, Jose S. "Thermodynamics of cyanide complexes". Thesis, Solis, Jose S. (1995) Thermodynamics of cyanide complexes. PhD thesis, Murdoch University, 1995. https://researchrepository.murdoch.edu.au/id/eprint/52731/.
Testo completoAbstract (sommario):
The work described in this thesis was to study the thermodynamics of the binding of cyanide to metal ions of relevance to the hydrometallurgical processing of gold. In particular, to produce reliable and accurate thermodynamic data needed to develop reliable chemical speciation models for the gold-refining industry, especially with regard to the high saline conditions of many Australian operations.
The stability constants of binary and ternary Cu(I) systems were studied using potentiometric glass electrode titration and evaluation of results by the ESTA suite of computer programs. In particular, the study of the Cu(I)-CN- system produced four major binary species in the conditions studied. The stability constants for the three species, Cu(CN)2-, Cu(CN)32-, and Cu(CN)43- are reported. The Cu(I)-NH3 system was attempted but oxidation of Cu(I) in the presence of ammonia was observed to be fast even in the absence of air. The presence of a high Cl" concentration stabilizes Cu(I) and since it also complexes with the metal the ternary system of Cu(I)-NH3-Cl- was considered. This study has established the existence of three ternary species, Cu(NH3)Cl°, CuNH3Cl2- and Cu(NH3)2Cl° together with the binary Cu(NH3)+ in the conditions of the present study. The other ternary system, Cu(I)-NH3-CN-, was studied but no analysis could be made with the present evaluation method. Failure of these experiments may be due to the closeness of the protonation constants of cyanide and ammonia in this medium, thus making it difficult to detect the minor effects in the experimental data which may arise from the ternary complex formation. Also, the experiment is restricted from the variation of the free cyanide and ammonia concentration because of the oxidation of Cu(I), volatility of NH3 at high p[H] and the volatility of HCN at low p[H].
Measurements of heat of reactions of common metal-cyanide systems were calorimetrically determined by the isoperibol continuous titration calorimeter. Enthalpies of metal-cyanide complexation were determined from these calorimetric measurements. Included in this study was the measurement of the heat of ionization of water and HCN as they were relevant to the metal-cyanide heats of reaction studies. These two systems were studied at variable ionic strength.
The solubility of AgCN and CuCN in HCN aqueous solution was studied. Another method of deriving equilibrium constants is from solubility measurements. The apparent solubility product constant of both AgCN and CuCN were sucessfully measured using the pH variation method.
Heat capacity measurements were conducted with cyanide solution using the Picker-flow calorimeter. Measurement of the volumetric heat capacities required densities which were measured accurately using a Vibrating Tube densimeter, thus the apparent molar volumes were also reported for these cyanide solutions. From these heat capacity measurements and other relevant literature data the change in heat capacity in association to the ionization of HCN was derived. For the first time, such data were determined calorimetrically and reported. The present values were obtained from NaCN and KCN respectively, and are, -228.5 and -222.8 J K-1mo-1. The results are in very good agreement and provides a most reliable estimate of ∆Cp° for the ionization of HCN.
By establishing reliable equilibrium constants in this way, a better and accurate description of the chemistry of a given aqueous cyanide solution is achieved. These thermodynamic information obtained at high saline medium serve to develop more realistic models of such hydrometallurgical solutions in local processing industries.
19
Marais, Charles Guillaume. "Thermodynamics and kinetics of sorption /". Link to the online version, 2008. http://hdl.handle.net/10019/1944.
Testo completo
20
Squadrani, Lorenzo. "Deep neural networks and thermodynamics". Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Cerca il testo completoAbstract (sommario):
Deep learning is the most effective and used approach to artificial intelligence, and yet it is far from being properly understood. The understanding of it is the way to go to further improve its effectiveness and in the best case to gain some understanding of the "natural" intelligence. We attempt a step in this direction with the aim of physics. We describe a convolutional neural network for image classification (trained on CIFAR-10) within the descriptive framework of Thermodynamics. In particular we define and study the temperature of each component of the network. Our results provides a new point of view on deep learning models, which may be a starting point towards a better understanding of artificial intelligence.
21
Schwarz, Thomas M. "Thermodynamics of the chiral condensate". [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=967122120.
Testo completo
22
Lee, Se Il. "Statistical thermodynamics of virus assembly". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33900.
Testo completoAbstract (sommario):
Experiments show that MgSO4 salt has a non-monotonic effect as a function of MgSO4 concentration
on the ejection of DNA from bacteriophage lambda.
There is a concentration, N0, at which the minimum amount of DNA is ejected.
At lower or higher concentrations, more DNA is ejected. We propose that this non-monotonic behavior
is due to the overcharging of DNA at high concentration of Mg⁺² counterions.
As the Mg⁺² concentration increases from zero, the net charge of ejected DNA changes its sign from negative to positive.
N0 corresponds to the concentration at which DNA is neutral.
Our theory fits experimental data well.
The DNA-DNA electrostatic attraction is found to be -0.004 kBT/nucleotide.
Simulations of DNA-DNA interaction of a hexagonal DNA bundle support our theory.
They also show the non-monotonic DNA-DNA interaction and reentrant behavior of DNA condensation by divalent counterions.
Three problems in understanding the capsid assembly for a retrovirus are studied:
First, the way in which the viral membrane affects the structure of in vivo assembled HIV-1 capsid is studied.
We show that conical and cylindrical capsids have similar energy at high surface tension of the viral membrane,
which leads to the various shapes of HIV-1 capsids. Secondly, the problem of RNA genome packaging inside spherical viruses
is studied using RNA condensation theory. For weak adsorption strength of capsid protein, most RNA genomes are located at the center
of the capsid. For strong adsorption strength, RNA genomes peak near the capsid surface and the amount of RNA packaged is proportional to the capsid area instead its volume. Theory fits experimental data reasonably well.
Thirdly, the condensation of RNA molecules by nucleocapsid (NC) protein is studied.
The interaction between RNA molecules and NC proteins is important for the reverse transcription of viral RNA which relates to the viral infectivity.
For strong adsorption strength of the NC protein, there is a screening effect by RNA molecules around a single NC protein.
23
Peppin, Stephen Stuart Lyman. "Nonequilibrium thermodynamics of concentration polarization". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0019/MQ47081.pdf.
Testo completo
24
Michel, Mathias. "Nonequilibrium aspects of quantum thermodynamics". Stuttgart M. Michel, 2006. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-28031.
Testo completo
25
Willman, Bert. "Continuous thermodynamics of fluid mixtures". Diss., Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/20176.
Testo completo
26
Haghtalab, Ali. "Thermodynamics of aqueous electrolyte solutions". Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74540.
Testo completoAbstract (sommario):
The focus of this work is the thermodynamics of aqueous solutions of strong electrolytes for both binary and multicomponent systems.A new excess Gibbs energy function to represent the deviations from ideality of binary electrolyte solutions was derived. The function consists of two contributions, one due to long-range forces, represented by the Debye-Huckel theory, and the other due to short-range forces represented by the local composition concept. The model is valid for the whole range of electrolyte concentrations, from dilute solutions up to saturation. The model consistently produces better results particularly at the higher concentration regions in which the other models deteriorate.
An electrochemical cell apparatus using Ion-Selective Electrodes (ISE) was constructed to measure the electromotive force (emf) of ions in the aqueous electrolyte mixtures. For the NaCl-NaNO$ sb3$-H$ sb2$O system, the data for the mean ionic activity coefficient of NaCl was obtained in order to show the reproducibility of literature data and to test the validity of the experimental procedure. The data for mean ionic activity coefficient of the following systems were also collected: (1) NaBr-NaNO$ sb3$-H$ sb2$O (a system with common ion); (2) NaBr-Ca(NO$ sb3$)$ sb2$-H$ sb2$O (a system with no-common-ion).
A novel mixing rule was proposed for the mean activity coefficients of electrolytes in mixtures in terms of the mean ionic activity coefficients of electrolytes in the binary solutions. The rule is applicable to multicomponent systems which obey Harned's Rule. Predictions are in excellent agreement with experimental data for ternary systems which follow the Bronsted specific ionic theory.
27
Pollard, David Michael. "Some problems in statistical thermodynamics". Thesis, University of Hull, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295938.
Testo completo
28
Avlonitis, Dimitrios Anastassios. "Thermodynamics of gas hydrate equilibria". Thesis, Heriot-Watt University, 1992. http://hdl.handle.net/10399/803.
Testo completoAbstract (sommario):
Reservoir fluids are usually saturated with water at reservoir conditions and may form gas hydrates in transfer lines, which potentially may plug the system. For long subsea pipelines, methanol injection is the practical means for preventing hydrate formation and for decomposing blockages. For efficient and economical pipeline design and operation, phase boundaries, phase fractions and distribution of water and methanol among the equilibrium phases of the system must be accurately known. The system comprising reservoir fluids, water and methanol demonstrates a complex multiphase behaviour and currently no quantitatively adequate description for it has been detailed in the open literature. The problem is addressed in this thesis by a consistent application of classical equilibrium thermodynamics. At ordinary operating conditions any combination of as many as six phases can be potentially present. For the description of the vapour and all liquid phases, we use one cubic equation of state with nonconventional mixing rules developed as part of this work. Classical thermodynamics together with the cell theory of van der Waals and Platteeuw were employed for the development of a general model for the calculation of heat capacities of gas hydrates. A consistent methodology has also been developed for obtaining the potential parameters of the cell model. Thereafter, application of the model demonstrates that for nearly spherical guest molecules the classical cell theory is a strictly valid description of gas hydrates. However, complex guest molecules distort the hydrate lattice, resulting in variation of the numerical values of certain parameters of the model. This work presents an efficient algorithm for the solution of the problem of the identity of the equilibrium phases in multiphase systems where gas hydrates are potentially present. The algorithm is based on the alternative use of two equivalent forms of the Gibbs tangent plane criterion and it is believed to be more appropriate for systems involving gas hydrate equilibria than previous methods. Application of the proposed algorithm in several regions of the phase diagram of both binary and multicomponent systems shows that it can be used reliably to solve any phase equilibria problem, including the location of phase boundaries. In summary this work presents a consistent, efficient and reliable scheme for multiphase equilibrium calculations of systems containing reservoir fluids, water and methanol. Favourable results have been obtained by comparison with diverse experimental data reported in the open literature and it is believed that the proposed correlation can be used reliably for pipeline design and operation.
29
Appels, Michael John. "Thermodynamics of accelerating black holes". Thesis, Durham University, 2018. http://etheses.dur.ac.uk/12737/.
Testo completoAbstract (sommario):
We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermo- dynamics, with the usual identification of entropy proportional to the area of the event horizon — even though the event horizon contains a conical singularity. We show how to generalise this result, formulating thermodynamics for black holes with varying conical deficits. We derive a new potential for the varying tension defects: the thermodynamic length, both for accelerating and static black holes. We discuss possible physical processes in which the tension of a string ending on a black hole might vary, and also map out the thermodynamic phase space of accelerating black holes and explore their critical phenomena. We then revisit the critical limit in which asymptotically-AdS black holes develop maximal conical deficits, first for a stationary rotating black hole, and then for an accelerated black hole, by taking various upper bounds for the parameters in the spacetimes presented. We explore the thermodynamics of these geometries and evaluate the reverse isoperimetric inequal- ity, and argue that the ultra-spinning black hole only violates this condition when it is nonaccelerating. Finally, we return to some of our earlier findings and adjust them in light of new results; a new expression for the mass is obtained by computing the dual stress-energy tensor for the spacetime and finding that it corresponds to a relativistic fluid with a nontrivial viscous shear tensor. We compare the holographic computation with the method of conformal completion showing it yields the same result for the mass.
30
Marais, Charl Guillaume. "Thermodynamics and kinetics of sorption". Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/1810.
Testo completo
31
Korzekwa, Kamil. "Coherence, thermodynamics and uncertainty relations". Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/43343.
Testo completoAbstract (sommario):
The principle of superposition is one of the main building blocks of quantum physics and has tremendous consequences both for our fundamental understanding of nature and for technological applications. In particular, the existence of coherent superposition leads to the concept of unavoidable quantum uncertainty. The role played by this "coherent" uncertainty within thermodynamics, as well as its relationship to classical lack of knowledge, is the main subject of this thesis. In Part I we study thermodynamic limitations of processing quantum coherence within a resource-theoretic framework. Using the time-translation symmetry that arises from the first law of thermodynamics, we find constraints on possible manipulations of coherence and prove their irreversibility due to the second law. We also generalise to the quantum domain Szilard's concept of converting information into work. Namely, we show how, in the presence of a heat bath, coherence of a system can be exploited to perform mechanical work. Finally, we analyse the effect that coherence has on the structure of the thermodynamic arrow of time, i.e., on the set of states into which a given state can freely evolve under thermodynamic constraints. In Part II we focus on the interplay between quantum and classical uncertainty manifested in uncertainty relations. We show that separating the total uncertainty into these two distinct components leads to a new type of "fixed-entropy" uncertainty relation. We also analyse how classical ignorance affects the structure of states that minimise the unavoidable uncertainty arising from the noncommutativity of two observables. Finally, we study error-disturbance trade-off relations and, by proving that quantum uncertainty can be simultaneously maximised for any two observables, we clarify the unphysical nature of state-dependent relations.
32
Soltanpour, Morteza [Verfasser]. "Thermodynamics of Neurotransmission / Morteza Soltanpour". Tübingen : Universitätsbibliothek Tübingen, 2021. http://d-nb.info/1236994256/34.
Testo completo
33
Silva, Ralph Francisco. "Entanglement, nonlocality, postselection and thermodynamics". Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.686187.
Testo completoAbstract (sommario):
In this second part of the thesis, we turn to the study of thermodynamics at the quantum scale, with a special focus on small thermal machines. To begin with, in Chapter 4, we look at the concept of a virtual temperature, as introduced in [43]. This is a temperature calculated for any pair of energy levels in a diagonal state by matching the ratio of its populations to the Gibbs state. The small quantum fridge introduced in Chapter 5, as well as all of the other small quantum thermal machines may be understood in terms of the virtual temperatures that they are able to generate within a system. We use the concept of virtual temperatures to construct an elegant and illuminating proof of the notion of complete passivity. A passive state [44] is one from which no work may be extracted from a unitary, while complete passivity refers to the property that no work can be extracted from multiple copies of a state.
34
Gemmer, Jochen. "A quantum approach to thermodynamics". [S.l. : s.n.], 2003. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10447209.
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35
Fontana, Weslei Bernardino. "S-AdS Black Hole Thermodynamics". Universidade Estadual de Londrina. Centro de Ciências Exatas. Programa de Pós-Graduação em Física, 2018. http://www.bibliotecadigital.uel.br/document/?code=vtls000217827.
Testo completoAbstract (sommario):
Durante os últimos 50 anos, a pesquisa acerca da teoria de buracos negros em relatividade geral trouxe luz para a existência de uma forte relação entre gravitação, termodinâmica e teoria de campos. Uma das partes mais importantes dessa conexão entre as teorias é a termodinâmica de buracos negros, que nos diz que algumas das leis que regem a mecânica de buracos negros são simplesmente as leis usuais da termodinâmica aplicada à um sistema com um buraco negro. O intuito deste trabalho é fazer uma revisão sobre o que se conhece atualmente acerca do assunto. Em especial, aplicado à teoria de buracos negros em espaços-tempo assintóticamente Anti de-Sitter. Daremos um enfoque especial ao formalismo Hamiltoniano da termodinâmica, o qual nos permite estender a descrição termodinâmica de buracos negros, ao se introduzir a constante cosmológica como um parâmetro no espaço de fase da teoria termodinâmica. O que nos fornece uma nova teoria termodinâmica com um grau de liberdade extra.For the last 50 years, the research around the theory of black holes in general relativity brought to light the existence of a strong relationship between gravitation, thermodynamics and field theory. One of the most important parts of this relationship between the theories, is the thermodynamics of black holes, which tell us that some of the laws that dictates the behavior of black holes are, in fact, the usual thermodynamical laws applied to a system containing a black hole. The goal of this work is to make a review about what is known in the present days about the subject, in special, applied to black holes in asymptotically Anti de-Sitter spacetimes. We shall focus on the Hamiltonian formalism to thermodynamics, which allow us to find a consistent way of extending the thermodynamic description for the black hole, by introducing the cosmological constant as a parameter in the phase space of the thermodynamical theory, giving birth to a new description with a new degree of freedom.
36
Ghosh, Sourav. "Thermodynamics of Margulis Space Time". Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112137/document.
Testo completoAbstract (sommario):
Dans ma thèse, je décris les feuilles stables et instables pour le flot géodésique sur l’espace des géodésiques non-errant de type espace d’un espace-temps de Margulis et je démontre des propriétés de contraction des feuilles sous le flot. Je montre aussi que la monodromie d’un espace-temps de Margulis est une représentation Anosov dans un groupe de Lie non semisimple. En outre, je montre que les applications limites et reparamétrisation varient analytiquement. Enfin, à l’aide de la propriété métrique Anosov, nous définissons la métrique de pression sur l’espace modulaire des espaces-temps de Margulis sans pointes et je démontre qu’elle est définie positive sur les sections d’entropie constanteIn my thesis I describe the stable and unstable leaves for the geodesic flow on the space of non-wandering spacelike geodesics of a Margulis Space Time and prove contraction properties of the leaves under the flow. I also show that monodromy of Margulis Space Times are “Anosov representations in non semi-simple Lie groups”. Moreover, I show that the limit maps and reparametrizations vary analytically. Finally using the metric Ansosov property we define the Pressure metric on the Moduli Space of Margulis Space Times without “cusps” and show that it is positive definite on the constant entropy sections
37
CARRISI, MARIA CRISTINA. "New results in extended thermodynamics". Doctoral thesis, Università degli Studi di Cagliari, 2008. http://hdl.handle.net/11584/265973.
Testo completoAbstract (sommario):
The subject of this thesis lays in the context of Extended Thermodynamics.
The classical methodology to solve the system of balance equations, in E.T., leads to difficult calculations. Recently a new methodology has been proposed to overcome these difficulties and to have more elegant equations, easier to solve. During my PhD, I worked in the direction of proving that the new methodology can be applied to the many moments case, to materials different from ideal gases and also in the relativistic case and not only in the classical one; furthermore I have been able to find the exact solutions for many of these problems.
After a brief introduction on Extended Thermodynamics, the new methodology will be shown, applied to the 5, the 13 and the 14 moments case for ideal gases. The last of these is a model obtained by Pennisi and myself. Afterwards I will show how we have applied the new methodology to dense gases and macromolecular fluids for the 13 and 14 moments case. After that I will present the results of my publications regarding the cases with an arbitrary but fixed number of moments for ideal gases, in the classical and in the relativistic context, and I will also show what happens when we consider their subsystems. Finally it will be considered a new kind of system of balance equations that is suggested from the non relativistic limit of the relativistic case.
38
DeSimone, Anthony Joseph Jr Gilmore Robert. "Symmetries and relaxations in non-equilibrium thermodynamics /". Philadelphia, Pa. : Drexel University, 2005. http://dspace.library.drexel.edu/handle/1860/483.
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39
Aschwanden, Andreas. "Mechanics and thermodynamics of polythermal glaciers /". Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17874.
Testo completo
40
Matthews, Jermey N. A. "Thermodynamics and relaxation during actin polymerization". College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2346.
Testo completoAbstract (sommario):
Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Chemical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
41
Voldsund, Mari. "Modelling distillation with non-equilibrium thermodynamics". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for kjemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-6864.
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42
Karatrantos, Argyrios. "Structure and thermodynamics of polyelectrolyte solutions". Thesis, University of Manchester, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.525184.
Testo completo
43
Chattopadhyay, Subrata. "Thermodynamics of hydrogen in electroslag remelting". Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/27041.
Testo completoAbstract (sommario):
Oxide ion activities in binary CaF₂ - CaO and ternary, CaF₂ -CaO - Al₂O₃ and CaF₂ - CaO -SiO₂, slags were determined by CO₂-slag
equilibrium experiments at 1400°C. The carbonate capacity of these slags
was computed and compared with the sulfide1 capacity data available in the
literature. The similarity in their trends suggests the possibility of
characterizing carbonate capacity as an alternative basicity index for
fluoride-based slags. The optical basicity of these slags is difficult to
define, and with the assumption of CaF₂ as an inert diluent, this parameter
did not show any distinct relationship with carbonate capacity. Slag-D20
equilibrium experiments were performed at 1400°C with binary ( CaF₂ -
CaO ) and ternary ( CaF₂ - CaO - Al₂O₃ and CaF₂ - CaO -SiO₂) slags to
determine water solubility at two different partial pressures of D₂O. A new
technique of slag sampling was employed using a quartz tube. A new and
reliable method of water analysis in ESR slags was developed. The new
water solubility data were higher than the previous data by an order of
magnitude, however, the solubility data showed a linear relationship with the
square root of water vapour partial pressure. Also, the solubility was at a
maximum in binary slags and a minimum in ternary slags containing SiO₂
with N[sub CaO]/N[sub SiO₂]≤2.
These experimental findings were used along with literature data to generate a new equilibrium ratio for hydrogen distributed between the slag and the metal during an ESR process. This information was further extended to compute the maximum permissible water content in an initial ESR slag for the production of an ESR ingot with an acceptable level of hydrogen.Applied Science, Faculty of
Materials Engineering, Department of
Graduate
44
Andrieux, David. "Nonequilibrium statistical thermodynamics at the nanoscale". Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210532.
Testo completoAbstract (sommario):
Motivés par les développements récents dans le domaine des nanosciences, nous étudions les propriétés statistiques et thermodynamiques des systèmes mésoscopiques. En particulier, nous nous concentrons sur les résultats connus sous le nom de théorèmes de fluctuation. Ces relations donnent des prédictions sur le comportement de différents quantités dynamiques dans des situations loin de l'équilibre, tout en tenant compte des fluctuations de l'évolution temporelle.\
Doctorat en sciences, Spécialisation physique
info:eu-repo/semantics/nonPublished
45
Cerrito, Stefano. "Thermodynamics of the BCS-BEC crossover". kostenfrei, 2007. http://mediatum2.ub.tum.de/doc/623023/document.pdf.
Testo completo
46
Alberti, Mathias V. "Thermodynamics of the Henon-Heiles oscillators". Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/13056.
Testo completo
47
Firoozi, Sadegh. "Thermodynamics and mechanisms of lead softening". Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100362.
Testo completoAbstract (sommario):
Visualization and quantitative oxidation kinetic experiments on 100 g samples of Pb-As at 600°C; thermal analysis and phase-equilibrium measurements of Pb-PbO-As2O3 samples under argon over the temperature range of 420°C to 875°C; computational thermodynamic solution modeling; and phase diagram and equilibrium calculations using FACTSage(TM) were performed to elaborate the poorly documented thermodynamics of the slags in the lead softening stage in the pyrometallurgical refining of lead. In the softening stage, the minor element impurities: arsenic, antimony and tin are removed from lead bullion by oxidation and are transferred to a skimmable oxide slag phase.It was found that optimizing an ionic molten oxide solution model that was conceptualized to contain Pb2+ and O2- with AsO3-4 and AsO3-3 ions, or with SbO3-4 and SbO3-3 ions in the respective PbO rich regions of the Pb-As-O and the Pb-Sb-O systems, was able to accurately reproduce the measured and published thermodynamic data. It was also found that the subsystems in the PbO-As2O 3-As2O5 and PbO-Sb2O3-Sb 2O5 systems showed small deviation from the ideal ionic solution model and small magnitude excess Gibbs energy parameters were sufficient to fit the predicted liquidus curves to the experimental measurements.
Arsenic in the +3 and +5 oxidation states was measured in the PbO rich region of the Pb-As-O liquid solution in the temperature range of 420°C to 875°C. The variability in the ratio of trivalent arsenic to the total arsenic content, as well as the complex variation of arsenic distribution between metal and oxide phases found strong interaction between the lead, arsenic and oxygen atoms at the 3PbO to 1AS2O3 molar ratio thus suggesting a short range ordering corresponding to the formation of AsO3-3 groupings, and indicating that the Pb3(AsO3) 2(l) species was likely to be present in the PbO rich region of the Pb-As-O system and contributing to an understanding of the Pb-As-O liquid oxide structure. Also, two new compounds (Pb3(AsO3) 2(s), Pb2AsO4(s)) were identified in the Pb-PbO-As 2O3 quenched samples via wavelength-dispersive spectrometry using the electron microprobe. The present work has application in commercial oxygen partial lead softening (OPLS), as uniquely practiced at Teck Cominco Ltd., British Columbia. There, pure oxygen gas is injected into the bath of impure bullion through a number of submerged lances in order to oxidize only part of the arsenic, antimony and tin into a slag phase. For such an operating practice, it was concluded from the visualization and quantitative oxidation experiments that the formation of solid oxides as the product of oxidation produced a physical barrier to the progress of oxidation and resulted in the commercially observed, highly-problematic, process initiation issues. When the product was liquid, there was much less of a barrier to rapid oxygen mass transfer to the minor element impurities and the softening reactions were easy to initiate. Such a change in the physical state of the products of oxidation was correlated to the optimized ternary Pb-As-O and Pb-Sb-O phase diagrams.
A current point of interest in partial lead softening is to increase the arsenic content of the slag phase. Arsenic distribution between lead bullion and slag calculated by the optimized solution model of the Pb-As-O system suggests that this can be achieved in a counter-current contacting of the slag and bullion.
48
Maruyama, Koji. "Information in quantum physics and thermodynamics". Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416077.
Testo completo
49
Hajdusek, Michal. "Thermodynamics, quantum computation and cluster states". Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531532.
Testo completo
50
Skrzypczyk, Paul Alan. "Aspects of nonlocality and quantum thermodynamics". Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.550302.
Testo completoAbstract (sommario):
This thesis is a tale of two stories. The first half of this thesis is dedicated to the study of nonlocality. We know that nature is inherently nonlocal, however, the nonlocal correlations allowed by quantum mechanics are limited; we could conceivably have correlations which are 'more' nonlocal and still cause no conflict with relativity. In this thesis I explore this limita- tion by studying nonlocality beyond quantum mechanics from a number of directions, relating mostly to dynamics and transformations. I show that the analogue of entanglement swapping and teleportation can in fact be implemented in a maximally nonlocal theory, as well as in theories with arbitrary limits on their nonlocality, Furthermore I show that nonlocality can be distilled, similarly to entanglement. This leads on to the study of when a nonlocal theory is dosed under a natural set of operations. Finally I make a tentative attempt at studying measures of nonlocality, by introducing notions of nonlocal cost and distillable nonlocality. The second half of this thesis is dedicated to the study of quantum thermodynamics. I explore the question of what are the absolute limits on the size of thermal machines? I present simple models of both quantum refrigerators as well as work-producing quantum heat engines, the smallest consisting of only a single qutrit coupled to two thermal baths. I show that both machines can reach the Carnot efficiency, and also that the refrigerator is able to cool towards absolute zero.