Dissertations / Theses on the topic 'Equilibrium Data'

Cyber attacks against companies are becoming more common as technology advances and digitalization is increasing exponentially. All Swedish insurance companies that sell cyber insurance encounter the same problem, there is not enough data to do good actuarial work. In order for the pricing procedure to improve and general knowledge of cyber insurance to increase, it has been proposed that insurance companies should share their data with each other. The goal of the thesis is to do mathematical calculations to explore data quality consequences of such a sharing regime. This thesis is based on some important assumptions and three scenarios. The most important assumptions are that there are two insurance companies forced to share all their data with each other and that they can reduce the uncertainty about their own product by investing in better data quality. In the first scenario, we assume a game between two players where they can choose how much to invest in reducing the uncertainty. In the second scenario, we assume that there is not a game, but the two insurance companies are forced to equal investments and thus have the same knowledge of their products. In the third scenario, we assume that the players are risk averse, that is, they are not willing to take high risk. The results will show how much, if any, the insurance companies should invest in the different scenarios to maximize their profits (if risk neutral) or utility (if risk averse). The results of this thesis show that in the first and second scenario, the optimal profit is reached when the insurance companies do not invest anything. In the third scenario though, the optimal investment is greater than zero, given that the companies are enough risk averse.

<p>The use of flux-splitting techniques on the Euler equations is considered for high Mach number, high temperature flows in which the fluid is assumed to be inviscid air in equilibrium. Three different versions of real gas extensions to the Stegerâ Warming and Van Leer flux-vector splitting, and four different versions of real gas extensions to the Roe flux-difference splitting, are compared with regard to general applicability and ease of implementation in existing perfect gas g algorithms. Test computations are performed for the M = 5, high temperature flow over a 10-degree wedge and the M = 24.5 flow over a blunt body. Although there were minor differences between the computed results for the three types of flux-splitting algorithms considered, little variation is observed between different versions of the same algorithm. </p><br>Master of Science

Thesis (MEng)--Stellenbosch University, 2014.<br>ENGLISH ABSTRACT: Thermodynamic models have been investigated extensively since Johannes van der Waals first devised a mathematical relation capable of predicting both vapour and liquid phases for a mixture at equilibrium. With the advent of modern computing power, these equations of state have gone from their humble empirical beginnings to the comprehensive and fundamentally derived models we have today. One such physically sound model is the Statistical Associating Fluid Theory (SAFT) family of equations, derived from the molecular perturbation theories of the 1980’s. The relative youth of this thermodynamic framework has meant that much work has gone into modification and optimisation of the model recently. The variants of particular interest to this work are the simplified perturbed chain SAFT equations with the Jog & Chapman (sPC-SAFTJC) and Gross & Vrabec (sPC-SAFTGV) polar terms. Each of the polar terms supports one adjustable polar parameter that relates to the quantity of polar segments in the reference fluid but not necessarily its position in the carbon chain. The strength of polar interactions is known to decrease as the functional group moves away from the terminal methyl group and the effects of steric hindrance increase. Thus, in question here is whether the models can account for the change in polar interactions associated with the changing position of the polar group, by only adjusting the values of the existing pure component parameters; that is, in lieu of a position specific parameter. The carbonyl group in ketone molecules is one such polar group, and it is this homologous series that is the focus of this study. The decrease in polar interactions as the carbonyl group in a ketone molecule shifts centrally is apparent from the lower boiling points of the isomers where the polar group is central as compared to those where the functional group is nearer the terminal methyl group. The effect of this functional group shift on binary phase behaviour has not previously been assessed for any system however, as the lack of experimental data attests. Thus, experiments had to be conducted to generate phase equilibrium data for systems comprising each structural isomer of a mid-length ketone with a common second component with no functionality. This limitation was imposed to isolate the cause of experimentally observed phenomena to the shifting polar group alone. The generated data could then be appropriately modelled using the polar sPC-SAFT variants and the capabilities of each model, as outlined above, assessed. To this end, isobaric binary vapour-liquid equilibrium data were measured for 2-, 3- & 4-heptanone with three separate normal alkanes of similar length (n-octane, n-nonane & n-decane) at 40kPa. The apparatus used was a dynamic Gillespie VLE still with temperature and pressure accuracies of 0.03°C and 1.6mbar respectively. Equipment verification was achieved through the reproduction of experimental data for the ethanol/1-butanol system at 1.013bar. The vapour and liquid samples for all nine systems were analysed by gas chromatography with a maximum compositional error of ±0.022 mole fraction. All reported data were found to be thermodynamically consistent using both the L/W and McDermott-Ellis consistency tests. When paired with a common n-alkane, all three structural heptanone isomers displayed similar qualitative trends in phase behaviour. Minimum boiling azeotropes were measured in all nine systems; in the high alkane region for n-octane systems (~98 mole%), the equal concentration region for n-nonane systems (34 mole% to 53 mole%) and in the very dilute n-alkane region for n-decane systems (~3 mole%). The n-nonane systems in particular highlighted the effect of shifting functional group, with completely separate phase envelopes away from the pure alkane composition space evident in a particularly small temperature range. Modelling was performed using in-house developed software, with pure component parameters generated for each system using five different regression procedures. The first was traditional fitting of the segment diameter (σ), segment number (m), segment energy (є/k) and the respective polar parameter (xp, np) to DIPPR correlations of pure component saturated vapour pressure, liquid density and the heat of vaporisation. The latter four procedures included the fixing of the polar parameter according to functional group correlations and the three instances of including the binary VLE data set for each of the three alkanes considered in this work. When applied to the nine binary ketone-alkane systems measured in this work, excellent predictions of the experimental data were in evidence in most cases and only small binary interaction parameters were necessary to correlate the data where pure predictions were poor. The performance of the parameter sets based on the fixing of the polar parameter and the inclusion of VLE data were consistent and of a high quality for both models, with near identical parameters generated in all four cases for each of the nine systems. The parameter sets generated in this fashion were shown to be applicable not only to the systems measured in this work, but also successfully predicted the independently measured experimental data of the n-hexane/4-heptanone system. It was thus concluded that either of these regression alternatives are viable for the generation of accurate component parameters, and the choice of VLE data set included is trivial. The pure predictions of the sPC-SAFTGV model were generally better than its sPC-SAFTJC counterpart, particularly in the case of the traditionally regressed parameter sets. sPC-SAFTGV displayed constant qualitative agreement with the experimental data for each of the heptanone isomers with a given n-alkane. The quality of the predictions of sPC-SAFTJC, however, worsened significantly as the polar interactions diminished from 2- to 4-heptanone, with no predictions even possible for the least polar isomer. This was attributed to the different perturbation theories used in the development of these terms, but a more detailed study would be necessary to confirm this. This work thus shows an apparent inability of the sPC-SAFTJC equation of state to account for the decreasing polar interactions associated with the carbonyl group in a ketone molecule shifting centrally, while sPC-SAFTGV produces qualitatively good fits for all three isomers. These flaws can be overcome through the incorporation of VLE data in the regression procedure if such data is available, or otherwise through the use of group specific correlations for fixing the polar parameter value.<br>AFRIKAANSE OPSOMMING: Sedert Johannes van der Waals die eerste wiskundige verhouding ontwikkel het wat beide die damp- en vloeibare fases van 'n mengsel by ewewig kon voorspel, is die veld van termodinamiese modellering al deeglik ondersoek. Na die koms van die moderne rekenaars het hierdie vergelykings van hul nederige empiriese wortels gegroei tot die omvattende, fundamentele modelle wat ons vandag het. Een so 'n fundamenteel gebaseerde familie van vergelykings is die ‘Statistical Associating Fluid Theory’ (SAFT) modelle, wat afgelei is vanaf molekulêre versteuringsteorieë, ontwikkel in die 1980s. Hierdie relatiewe jong modelle het in die afgelope ruk aansienlike aanpassing en optimering ondervind. Modelvariante van besondere belang tot hierdie werk, is die vereenvoudigde versteurde ketting of ‘simplified perturbed chain’ SAFT vergelykings, met Jog & Chapman (sPC- SAFTJC) en Gross & Vrabec (sPC- SAFTGV) polêre terme. In die sPC-SAFT toestandsvergelyking word elkeen van die polêre terme ondersteun deur een polêre veranderlike. Hierdie veranderlike is afhanklik van die aantal polêre segmente in die verwysingsvloeistof, maar nie noodwendig hul posisie in die koolstofketting nie. Daarteen is dit bekend dat die polêre interaksies tussen molekules swakker word soos die polêre groep wegbeweeg van die terminale metielgroep, en steriese hindernis ʼn groter rol begin speel. Dus is die vraag of die model die verandering in die polêre interaksie, as gevolg van veranderende posisie van die polêre groep, kan voorspel deur in plek van ʼn posisie afhanklike parameter, slegs ʼn aanpassing van die polêre waardes van die suiwer komponente te maak. Die karbonielgroep in ketoon molekules is een so 'n polêre groep, en ʼn homoloë reeks ketone word in hierdie studie ondersoek. Die afname in die polêre interaksie soos wat die karbonielgroep in 'n ketoon molekule weg skuif vanaf die terminale metiel groep is sigbaar deur die afname in kookpunt van die verskillende isomere. Hierdie effek van die funksionele groepsposisie op binêre fasegedrag is nog nie voorheen vir enige stelsels geëvalueer nie en geen eksperimentele data is vrylik beskikbaar nie. Om hierdie tekortkoming in die literatuur aan te spreek, is eksperimentele fase ewewig data gemeet. ʼn Reeks stelsels is ondersoek wat elk bestaan uit ʼn struktuurisomeer van ʼn mid-lengte ketoon en ʼn tweede komponent met geen funksionele bydrae. Eksperimente is so opgestel om die effek van die skuiwende polêre groep op die fasegedrag te isoleer en kwalitatief te ondersoek. Die gegenereerde data is dan gemodelleer met behulp van die polêre sPC- SAFT variante, soos hierbo gespesifiseer, en die vermoëns van elke model is beoordeel. Isobariese binêre fase ewewig data is by 40kPa gemeet vir damp-vloeistof stelsels bestaande uit 2, 3 & 4 heptanoon, gemeng met drie verskillende normaal alkane van vergelykbare kettinglengte (n-oktaan, n-nonaan & n-dekaan). Die apparaat wat gebruik was is 'n dinamiese Gillespie VLE eenheid met temperatuur- en drukakkuraatheid van 0,03°C en 1.6mbar, onderskeidelik. Die akkuraatheid van die toerusting is bevestig deur eksperimentele data vir ʼn etanol/1-butanol stelsel by 1.013bar te reproduseer. Die damp en vloeibare monsters vir al nege stelsels is ontleed deur gaschromatografie met 'n maksimum komposisionele fout van ± 0,022 (molfraksie). Alle data is as termodinamies konsekwent gevind deur van beide die L/W en McDermott-Ellis konsekwentheidstoetse gebruik te maak. Mengsels van die drie strukturele isomere van heptanoon met ʼn gemene n-alkaan het tydens eksperimente soortgelyke kwalitatiewe tendense in fasegedrag getoon. Gedurende eksperimente is die lae kookpunt asiotrope gemeet vir al nege stelsels. Die asiotrope verskyn in die hoë alkaan konsentrasies (~98 mol%) vir n-oktaan stelsels, medium konsentrasies (34 mol% tot 53 mol%) vir n-nonaan stelsels en baie verdunde konsentrasies (~ 3 mol%) vir n-dekaan stelsels. Die n-nonaan stelsels beeld veral die effek van die verskuiwing van die funksionele groep uit, met diskrete fasegrense wat duidelik apart staan van die suiwer alkaan ruimte, binne ʼn klein temperatuurverskil. Modellering van die stelsels is uitgevoer met behulp van sagteware wat in-huis ontwikkel is. Suiwer komponent data is gegenereer vir elke stelsel deur van vyf verskillende regressie prosedures gebruik te maak. Die eerste is die tradisionele passing van die segment deursnee (σ), segment nommer (m), segment energie (є/k) en die onderskeie polêre parameters (xp, np) op DIPPR korrelasies van die suiwer komponent versadigde dampdruk, vloeistof digtheid en die hitte van verdamping. Die oorblywende vier prosedures sluit in die bepaling van die polêre parameter deur funksionelegroep korrelasies, en drie gevalle waar die binêre VLE data vir elk van die drie alkane ingesluit is. Deur hierdie prosedures op die modellering van die nege binêre ketoon/alkaan stelsels toe te pas, is uitstekende passings van die eksperimentele data verkry met slegs baie klein binêre interaksie parameters nodig waar voorspellings minder akkuraat was. Die prestasie van die parameter stelle, gebaseer op die bepaling van die polêre parameter en die insluiting van VLE data, is konsekwent en van 'n hoë gehalte vir albei modelle, met 'n byna identiese parameters gegenereer in al vier gevalle vir elk van die nege stelsels. Die parameter stelle wat op hierdie metode gegenereer is, is nie net toepaslik gevind op eksperimentele data gemeet in hierdie werk nie, maar ook op onafhanklike data vir die n-heksaan/4-heptanoon stelsel. Daar is tot die gevolgtrekking gekom dat beide van die regressie alternatiewe lewensvatbaar is vir die generasie van akkurate suiwer komponent parameters, en dat die insluiting van die VLE data triviaal is. Die suiwer sPC - SAFTGV voorspelling was oor die algemeen beter as die suiwer sPC- SAFTJC model met die voorspelling van data, veral in die geval van passings gedoen met parameters verkry vanaf tradisionele regressie metodes. sPC- SAFTGV het ʼn voortdurende, kwalitatiewe ooreenkoms met eksperimentele data getoon vir elk van die nege stelsels. Daarteen het voorspellings deur sPC- SAFTJC beduidend verswak soos die polêre interaksies afgeneem het vanaf 2- na 4- heptanoon, met geen akkurate voorspelling moontlik vir die minste polêre isomeer nie. Die verskynsel kan toegeskryf word aan die verskil in versteuringsteorieë wat gebruik word in die ontwikkeling van die onderskeie toestandsvergelykings, maar ʼn meer in-diepte ondersoek is nodig om hierdie teorie te bevestig. Hierdie werk toon dus 'n skynbare onvermoë van die sPC - SAFTJC toestandsvergelyking om die verandering in polêre interaksie, as gevolg van die veranderende posisie van die polêre groep, vir die karbonielgroep in ʼn ketoon te voorspel, terwyl die sPC-SAFTGV toestandsvergelyking goeie kwalitatiewe passings vir al drie isomere bied. Hierdie tekortkominge kan oorkom word deur VLE data, indien beskikbaar, in die regressie prosedure in te sluit, of deur die gebruik van groep spesifieke korrelasies vir die aanpassing van die polêre parameter.

In this thesis, we study the kinetic disordering of systems interacting with an agent or a walker. Our studies divide naturally into two classes: for the first, the dynamics of the walker conserves the total magnetization of the system, for the second, it does not. These distinct dynamics are investigated in part I and II respectively. In part I, we investigate the disordering of an initially phase-segregated binary alloy due to a highly mobile vacancy which exchanges with the alloy atoms. This dynamics clearly conserves the total magnetization. We distinguish three versions of dynamic rules for the vacancy motion, namely a pure random walk , an ``active' and a biased walk. For the random walk case, we review and reproduce earlier work by Z. Toroczkai et. al.,~cite{TKSZ} which will serve as our base-line. To test the robustness of these findings and to make our model more accessible to experimental studies, we investigated the effects of finite temperatures (``active walks') as well as external fields (biased walks). To monitor the disordering process, we define a suitable disorder parameter, namely the number of broken bonds, which we study as a function of time, system size and vacancy number. Using Monte Carlo simulations and a coarse-grained field theory, we observe that the disordering process exhibits three well separated temporal regimes. We show that the later stages exhibit dynamic scaling, characterized by a set of exponents and scaling functions. For the random and the biased case, these exponents and scaling functions are computed analytically in excellent agreement with the simulation results. The exponents are remarkably universal. We conclude this part with some comments on the early stage, the interfacial roughness and other related features. In part II, we introduce a model of binary data corruption induced by a Brownian agent or random walker. Here, the magnetization is not conserved, being related to the density of corrupted bits }$ ho ${small .} {small Using both continuum theory and computer simulations, we study the average density of corrupted bits, and the associated density-density correlation function, as well as several other related quantities. In the second half, we extend our investigations in three main directions which allow us to make closer contact with real binary systems. These are i) a detailed analysis of two dimensions, ii) the case of competing agents, and iii) the cases of asymmetric and quenched random couplings. Our analytic results are in good agreement with simulation results. The remarkable finding of this study is the robustness of the phenomenological model which provides us with the tool, continuum theory, to understand the nature of such a simple model.<br>Ph. D.

Chapter 1 introduces some of the issues which are addressed in the other chapters of this dissertation. These topics include: (1) the general equilibrium incentives in the provision of public education, (2) human capital production functions in economic modeling, (3) how public education spending may impact income inequality -- both positively and negatively, (4) the effect on public education spending of changes in the college wage premium, and (5) the overall efficiency of government-supplied capital. Chapter 2 develops a public education system in which voters face general equilibrium incentives to pay taxes for education. Middle-aged voters can increase their returns to saving by increasing the aggregate amount of human capital in the economy. I find that if students differ by their ability to increase their human capital levels through schooling, then the public education policy will invest more education funds in more productive students; this perpetuates income inequality. Also, the greater the discount rate for consumption and the elasticity of education funds in the human capital production function, the more likely it is that a public system provides greater growth in the steady state than a private system. Chapter 3 studies the allocation of government spending between general tuition subsidies for college students and need-based aid which is directed solely towards students from low-income households. The way to maximize the number of students may be to provide some need-based aid. I find that government provides more aid directed to low-income students if need-based tuition subsidies are provided rather than student loan subsidies. I also look at the effects of changes in parameters, such as the cost of education and the college wage premium, on the policies. Chapter 4 investigates the returns to aggregate factors of production when labor is disaggregated by education level. I find that a model in which the error term is assumed to be state-wise heteroscedastic and autocorrelated does a better job of approximating the pattern of wages for the different education groups than other models (pooled OLS or random and fixed effects). In addition, this model suggests a significant positive elasticity for public capital.<br>Ph. D.

Thesis: S.M. in Technology and Policy, Massachusetts Institute of Technology, School of Engineering, Institute for Data, Systems, and Society, Technology and Policy Program, 2017.<br>Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 128-134).<br>The use of methanol as a transportation fuel is not a new phenomenon. However, factors such as price fluctuations, resistance to widespread introduction by special interest groups, and governmental policies have stood in the way of the widespread use of methanol in covering transportation demand. In this thesis, a computable general equilibrium energy-economy model of the world, the Economic Projection and Policy Analysis (EPPA) model, is used to evaluate the potential for methanol vehicle penetration in the private passenger vehicle market in China depending on the cost competitiveness of the technology combination compared to electric and conventional vehicles, the relative prices of methanol and gasoline, and the application of various policies. The use of methanol in light duty passenger vehicles has risen heavily in China due to the abundance of coal in the country and the ability to use it as the feedstock for methanol production in China, thereby reducing China's reliance on foreign oil imports. Additionally, the lower price of methanol fuel compared to gasoline has led it to be an attractive fuel choice from the customer perspective due its favorable economics, with a growing number of individuals converting their conventional vehicles to be able to run on methanol. Since China is not a country abundant with natural gas, the two leading options for obtaining methanol are obtaining it through the use of coal as the feedstock locally or importing it from other countries which are producing methanol using natural gas. Methanol fuel production pathways and the vehicle technology are introduced in EPPA as a substitute for conventional Internal Combustion Engine (ICE) vehicles. Engineering cost estimates as well as existing transportation expenditure trends in China are used for obtaining the input shares and elasticities of substitution as inputs to the model. Simulations are then run until 2050 to understand the rate at which the methanol vehicle technology penetrates the market when competing with electric vehicles and conventional vehicles in the base case scenario. Accordingly, changes in greenhouse gas emissions and particulate emissions are calculated. On the policy side, various sets of policies are tested: instituting a gasoline tax, banning methanol imports for use in passenger private vehicles, applying various combinations of vehicle subsidies for methanol and electric vehicles, and instituting a carbon cap at a national level. Various conclusions emerge from this thesis. First, the penetration of methanol and electric vehicles are slow, achieving market shares of 4% and 1%, respectively. Despite the lower methanol cost compared to gasoline, the penetration of the technology is slowed down by the higher cost of methanol vehicles compared to conventional vehicles as well as the delays associated with introducing new fuels, new vehicles, and new refueling infrastructure, none of which are completely compatible with the incumbent technology. This shift also results in an increase in greenhouse gas emissions compared to the business as usual scenario but a decrease in emissions of nitrogen oxides, carbon monoxide, and hydrocarbons. Instituting a gasoline tax has a greater impact than existing Chinese vehicle subsidy policies on methanol and electric vehicle penetration. However, the gasoline tax still results in modest methanol and electric vehicle penetration, achieving a market share of 6% each by 2050. Setting a carbon cap under an accelerated effort scenario impacts the vehicle trends most dramatically, completely driving down the use of methanol vehicles and allowing electric vehicles to achieve an 11.47% market share. Finally, these results are used to present various policy recommendations depending on China's existing provincial policy structures, its national objectives, and future goals.<br>by Mahsa Nami.<br>S.M. in Technology and Policy<br>S.M.

This thesis develops a one-dimensional version of a new data driven model of turbulence that uses the KL expansion to provide a spectral solution of the turbulent flow field based on analysis of Particle Image Velocimetry (PIV) turbulent data. The analysis derives a 2nd order random field over the whole flow domain that gives better turbulence properties in areas of non-uniform flow and where flow separates than the present models that are based on the Navier-Stokes Equations. These latter models need assumptions to decrease the number of calculations to enable them to run on present day computers or super-computers. These assumptions reduce the accuracy of these models. The improved flow field is gained at the expense of the model not being generic. Therefore the new data driven model can only be used for the flow situation of the data as the analysis shows that the kernel of the turbulent flow field of undular hydraulic jump could not be related to the surface waves, a key feature of the jump. The kernel developed has two parts, called the outer and inner parts. A comparison shows that the ratio of outer kernel to inner kernel primarily reflects the ratio of turbulent production to turbulent dissipation. The outer part, with a larger correlation length, reflects the larger structures of the flow that contain most of the turbulent energy production. The inner part reflects the smaller structures that contain most turbulent energy dissipation. The new data driven model can use a kernel with changing variance and/or regression coefficient over the domain, necessitating the use of both numerical and analytical methods. The model allows the use of a two-part regression coefficient kernel, the solution being the addition of the result from each part of the kernel. This research highlighted the need to assess the size of the structures calculated by the models based on the Navier-Stokes equations to validate these models. At present most studies use mean velocities and the turbulent fluctuations to validate a models performance. As the new data driven model gives better turbulence properties, it could be used in complicated flow situations, such as a rock groyne to give better assessment of the forces and pressures in the water flow resulting from turbulence fluctuations for the design of such structures. Further development to make the model usable includes; solving the numerical problem associated with the double kernel, reducing the number of modes required, obtaining a solution for the kernel of two-dimensional and three-dimensional flows, including the change in correlation length with time as presently the model gives instant realisations of the flow field and finally including third and fourth order statistics to improve the data driven model velocity field from having Gaussian distribution properties. As the third and fourth order statistics are Reynolds Number dependent this will enable the model to be applied to PIV data from physical scale models. In summary, this new data driven model is complementary to models based on the Navier-Stokes equations by providing better results in complicated design situations. Further research to develop the new model is viewed as an important step forward in the analysis of river control structures such as rock groynes that are prevalent on New Zealand Rivers protecting large cities.

Orientadores: Eduardo Augusto Caldas Batista, José Vladimir de Oliveira<br>Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos<br>Made available in DSpace on 2018-08-22T05:44:32Z (GMT). No. of bitstreams: 1 Dalmolin_IredeAngelaLucini_D.pdf: 9550332 bytes, checksum: 061256cf12d61dd7b97065d987efd625 (MD5) Previous issue date: 2013<br>Resumo: A utilização de resíduos e o emprego de tecnologias ambientalmente seguras são tendências gerais de pesquisa da comunidade científica, impulsionadas pelas exigências governamentais e apelo do mercado consumidor, que buscam cada vez mais produtos naturais de alta qualidade. Neste contexto, o objetivo deste trabalho foi obter o extrato de sementes de uva através de extração por fluido supercrítico, caracterizá-lo química e fisicamente, e aplicá-lo ao encapsulamento em poli-(hidroxibutirato-cohidroxivalerato) utilizando tecnologia de antissolvente supercrítico. Para tanto, o estudo do ponto de vista termodinâmico, através de dados de equilíbrio de fases e modelagem, fez-se necessário para obtenção de informações dos sistemas de interesse à extração bem como ao encapsulamento. A caracterização desse extrato aponta uma importante fonte natural de ácido linoléico, como componente majoritário, e também de ácidos oléico, palmítico e esteárico, e de antioxidantes e fitoesteróis. Através de separadores dispostos em série foi possível fracionar por meio de despressurização e obter extratos com diferentes composições desejadas. Na determinação de dados de equilíbrio de fases do sistema Extrato de Sementes de Uva (ESU) + Dióxido de Carbono (CO2) + Etanol, verificou-se que a quantidade de água no extrato, remanescente da matéria-prima, prejudicava a obtenção de dados de equilíbrio com porcentagens de (CO2 + Etanol) inferiores a 70 %. Observaram-se transições bifásicas do tipo Líquido-Vapor Ponto de Bolha (LV-PB), Líquido-Vapor Ponto de Orvalho (LV-PO) e Líquido-Líquido (LL), e trifásicas do tipo Líquido-Líquido-Vapor (LLV). Com a redução de água no ESU foi possível descrever o comportamento do equilíbrio de fases, porém para ambas as temperaturas estudadas ocultaram-se as transições LV-PO. Para o mesmo sistema, a modelagem foi feita utilizando a equação de Peng-Robinson, que foi capaz de correlacionar os dados com a utilização de dois parâmetros de interação binária ajustados. Dados de equilíbrio de fases do sistema ESU + CO2 +Diclorometano (DCM) foram determinados onde transições bifásicas do tipo LV-PB e LVPO foram observadas. Verificou-se que a adição de ESU em solução de DCM, em concentrações de até 15 kg·m-3, não influenciou nas pressões de transição do sistema binário CO2 + DCM. O encapsulamento foi realizado com percentual de encapsulamento de até 72 % de ESU<br>Abstract: The use of residues and environmentally safe and benign technologies comprise a general research trend of scientific community, stimulated by government requirements and appeal to the consumer market which increasingly seek natural products of high quality. In this context, the aim of this work was to obtain grape seed extract by supercritical fluid extraction, characterize it chemically and physically, and apply it to the encapsulation in polymer poly-(hydroxybutyrate-co-hydroxyvalerate) using supercritical anti-solvent technology. Thus, the study from the thermodynamic point of view, by phase equilibrium data and modeling, was necessary to obtain information of the interest system for the extraction and for encapsulation. According to the characterization, grape seed extract is an important natural source of linoleic acid, as major component, and also by oleic, palmitic and stearic acids, and antioxidants and phytosterols. Through separators displayed in series was possible to fractionate the depressurization and to obtain extracts with different desired compositions. In the determination of phase equilibrium data of the system Grape Seed Extract (GSE) + Carbon Dioxide (CO2) + Ethanol, it was found that the amount of water in the extract, remaining in the raw materials, limited obtaining equilibrium data with percentages of (CO2 + ethanol) lower than 70 %. Two-phase transitions were observed, Vapor-Liquid Bubble Point (VL-BP), Vapor-Liquid Dew Point (VL-DP), and Liquid-Liquid (LL), and three-phase transitions Vapor-Liquid-Liquid (VLL). With the reduction of water in the GSE was possible to describe phase equilibrium behavior, but for both temperatures studied were put out transitions VL-DP. For the same system, the modeling was performed using Peng-Robinson equation which was able to correlate data with the use of two adjusted binary interaction parameters. Phase equilibrium data of GSE + CO2 +dichloromethane (DCM) system were determined where two-phase transitions VL-BP and VL-DP were observed. It was verified that the addition of GSE to the DCM solution in concentration up to 15 kg·m-3 did not affect the transition pressure of the binary system CO2 + DCM. The encapsulation was realized with percentage of encapsulation up to 72 % of GSE<br>Doutorado<br>Engenharia de Alimentos<br>Doutora em Engenharia de Alimentos

A utilização de modelos de equilíbrio-geral estocásticos e dinâmicos (DSGE) para o estudo detalhado das relações entre variáveis econômicas reais e nominais tem crescido substancialmente nos últimos anos. Avanços computacionais recentes contribuíram significativamente para este movimento, permitindo que a modelagem DSGE se torne cada vez mais precisa, superando técnicas menos restritivas de modelagem macroeconômica. Contudo, a estimação destes modelos, usualmente realizada através de métodos Bayesianos, apresenta problemas, como a alta dependência da distribuição a priori. A principal inovação desta tese é propor uma solução para estes problemas, ao apresentar e utilizar o método de datacloning para estimar uma versão simplificada do modelo DSGE de Gali e Monacelli (2005), com o objetivo de avaliar a condução da política monetária pelo Banco Central do Brasil (BCB). Os principais resultados encontrados indicam que o BCB segue uma política anti-inflacionária, reage ao produto e a variações cambiais, além de gerar uma trajetória suave para a taxa de juros ao longo do tempo. Foram encontrados indícios de que a alteração de estratégia do BCB a partir de 2010, com a introdução de uma série de medidas macroprudenciais, não configurou quebra na condução da política monetária.<br>The use of dynamic stochastic general equilibrium (DSGE) models for the detailed study of the relationship between real and nominal economic variables has grown substantially in recent years. Computational advances have contributed significantly to this movement, allowing DSGE modelling to become increasingly precise, surpassing less restrictive macroeconomic modelling techniques. However, the estimation of these models, usually performed with Bayesian methods, presents problems, such as high dependence on the prior distribution. The main innovation of this thesis is to propose a solution to these problems, presenting and using the data cloning method to estimate a simplified version of Gali and Monacelli (2005)’s DSGE model, in order to assess the conduct of monetary policy by the Central Bank of Brazil (BCB). The main findings of this thesis indicate that the BCB follows an anti-inflationary policy, responds to GDP and exchange rate changes, and chooses a smooth interest rate path over time. Evidence suggests that the change in BCB’s strategy from 2010 onwards, with the introduction of a series of macroprudential measures, is not a conclusive indication of a parameter break in its reaction function.

Orientadores: Maria Alvina Krahenbuhl, Antonio Jose de Almeida Meirelles<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica<br>Made available in DSpace on 2018-08-04T19:22:03Z (GMT). No. of bitstreams: 1 Boros_LasloAndreDjevi_M.pdf: 2305152 bytes, checksum: 3c079eaeca07d356820561decab9dffe (MD5) Previous issue date: 2005<br>Resumo: O objetivo deste trabalho foi realizar a modelagem matemática e termodinâmica do equilíbrio sólido-líquido de sistemas constituídos pelos ácidos graxos e triglicerídeos. A importância deste estudo está relacionada ao fato destas substâncias serem os principais constituintes dos óleos e gordura, que possuem grande aplicação em diversas áreas das industrias alimentícias, farmacêutica e química. A principal característica do equilíbrio sólido-líquido dos sistemas graxos é a possibilidade de formação de um composto na fase sólida, identificado pela presença do ponto peritético na curva de equilíbrio. De posse desta informação foram empregados modelos que permitissem representar a formação deste composto. Para os sistemas graxos em que não há formação de compostos na fase sólida foram empregados os modelos derivados da abordagem tradicional do equilíbrio sólido-líquido e também a metodologia de COUTINHO e RUFFIER-MERAY (1998), que permite a obtenção do diagrama de fases a partir de poucas medidas experimentais obtidas através do DSC. Já para os casos em que há formação de composto na fase sólida foi aplicada a metodologia de SLAUGHTER e DOHERTY (1995), que trata a formação de composto como uma reação química, e também foi desenvolvido um novo modelo que representa a formação do composto como uma transição sofrida por um dos componentes presentes na mistura... Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital<br>Abstract: The propose of this work was to carry through the mathematical and thermodynamical modeling of the solid-Iiquid equilibrium of systems consisting of fatty acids and triglycerides. The importance of this study is related to the fact that substances are the main constituent of oils and fats, which possess great application in several areas of the food, pharmaceutical and chemical industries. The main characteristic of solid-liquid equilibrium of the fatty systems is the possibility of formation of a compound in the solid phase, identified for the presence of the peritetic point in the equilibrium curve. Of ownership of this information models had been used that allowed to represent the formation of this compound. For the fatty systems where it does not have formation of compound in the solid phase had been used the models derived from the traditional treatment of the solid-liquid equilibrium and also the methodology of COUTINHO and RUFFIER-MERAY (1998), which allows the attainment of phases diagrams from few gotten experimental measures through the DSC. Already for the cases where it has formation of composition in the solid phase was applied the SLAUGHTER and DOHERTY (1995) methodology, which deals with the formation composition as a chemical reaction, and also was developed a new model that represents the formation of the composition as a polymorphic transition suffered for one from the components in the mixture... Note: The complete abstract is available with the full electronic digital thesis or dissertations<br>Mestrado<br>Desenvolvimento de Processos Químicos<br>Mestre em Engenharia Química

The pervasive availability of streaming data from various sources is driving todays’ enterprises to acquire low-latency big data streaming applications (BDSAs) for extracting useful information. In parallel, recent advances in technology have made it easier to collect, process and store these data streams in the cloud. For most enterprises, gaining insights from big data is immensely important for maintaining competitive advantage. However, majority of enterprises have difficulty managing the multitude of BDSAs and the complex issues cloud technologies present, giving rise to the incorporation of cloud service brokers (CSBs). Generally, the main objective of the CSB is to maintain the heterogeneous quality of service (QoS) of BDSAs while minimizing costs. To achieve this goal, the cloud, although with many desirable features, exhibits major challenges — resource prediction and resource allocation — for CSBs. First, most stream processing systems allocate a fixed amount of resources at runtime, which can lead to under- or over-provisioning as BDSA demands vary over time. Thus, obtaining optimal trade-off between QoS violation and cost requires accurate demand prediction methodology to prevent waste, degradation or shutdown of processing. Second, coordinating resource allocation and pricing decisions for self-interested BDSAs to achieve fairness and efficiency can be complex. This complexity is exacerbated with the recent introduction of containers. This dissertation addresses the cloud resource elasticity management issues for CSBs as follows: First, we provide two contributions to the resource prediction challenge; we propose a novel layered multi-dimensional hidden Markov model (LMD-HMM) framework for managing time-bounded BDSAs and a layered multi-dimensional hidden semi-Markov model (LMD-HSMM) to address unbounded BDSAs. Second, we present a container resource allocation mechanism (CRAM) for optimal workload distribution to meet the real-time demands of competing containerized BDSAs. We formulate the problem as an n-player non-cooperative game among a set of heterogeneous containerized BDSAs. Finally, we incorporate a dynamic incentive-compatible pricing scheme that coordinates the decisions of self-interested BDSAs to maximize the CSB’s surplus. Experimental results demonstrate the effectiveness of our approaches.

Orientadores: Maria Alvina Krahenbuhl, Antonio Jose de Almeida Meirelles<br>Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica<br>Made available in DSpace on 2018-08-11T21:21:37Z (GMT). No. of bitstreams: 1 Costa_MarianaConceicaoda_D.pdf: 10674816 bytes, checksum: 76cfbb726dcbf23a7bdf88f2ccf727bd (MD5) Previous issue date: 2008<br>Resumo: Os ácidos graxos são importantes não só por serem os principais constituintes dos óleos e gorduras de origem vegetal, mas também por terem grande importância no funcionamento de alguns sistemas lipídicos e porque podem ser usados como matéria prima na fabricação de emulsões, plásticos e produtos de limpeza entre outros. Além da grande influência que causam nas características finais de alguns produtos da indústria alimentícia, recentemente pesquisas também os apontam como bons materiais para o armazenamento de energia (phase change materials ¿ PCMs). Nesse trabalho são apresentados diagramas T-x do Equilíbrio Sólido-Líquido de sistemas binários de ácidos graxos saturados através de uma reinterpretação das curvas térmicas obtidas pela calorimetria exploratória diferencial. Esses diagramas de fase apresentam os pontos peritético e eutético além de transições na fase sólida. Esse trabalho investiga detalhadamente a fase sólida das misturas de ácidos graxos saturados, com a intenção de compreender a existência do ponto peritético e das transições na fase sólida que aparecem nos diagramas de equilíbrio. Para esse estudo foram usadas as técnicas de difração de Raios-X, de espalhamento Raman, a microscopia óptica convencional, a microscopia óptica a altas pressões e a calorimetria exploratória diferencial, através da qual foram determinados os diagramas de fase estudados. Através desse estudo foi possível apresentar um diagrama de fases muito mais complexo do que até agora foi encontrado na literatura. Essa complexidade se deve, além da reação peritética e da reação eutética, já conhecidas desses sistemas, a uma reação metatética que ocorre logo acima da temperatura peritética. Também há a formação de solução sólida nos extremos do diagrama de fases, comprovada através do diagrama de Tamman e a uma região de completa miscibilidade, devido à formação de um composto com ponto de fusão incongruente.<br>Abstract: Fatty acids are important not just to be the main constituent of oils and fats but also because of the important behavior of lipids systems and that can be used as row materials in the manufacture of emulsions, plastics and products for cleaning and others. Besides of the big influenced that causes in the final characteristics of some products for food industries recent research points that they are excellent phase change materials (PCMs). This work presents T-x diagrams of solid-liquid equilibrium of binary systems of saturated fatty acids through the reinterpretation of the differential thermal curves obtained by differential scanning calorimetry. These phase diagrams presents the peritectic and eutectic points besides the transitions on the solid phase. This work studies the solid phase of saturated fatty acids mixtures looking forward to verify the occurrence of the peritectic point and the transitions on the solid phase. For this study it was used the following techniques: X-ray diffratometry, FT-Raman spectroscopy, conventional optical microscopy, optical microscopy under high pressure and differential scanning calorimetry. The phase diagrams studied were determined by differential scanning calorimetry. The results obtained through these techniques shows a phase diagram more complex than previously reported in the literature. This complexity is due to a peritectic and eutectic, and to a metatectic reaction that occurs closer to the peritectic temperature. Besides these reactions there is formation of solid solution on the extremes of the phase diagram proven by the Tamman plot and the existence of a region with complete miscibility, close to the peritectic point, due the formation of a compound with incongruently melting point.<br>Doutorado<br>Desenvolvimento de Processos Químicos<br>Doutor em Engenharia Química

Utilizando o modelo gravitacional, estimado através da Pseudo Máxima Verossimilhança de Poisson com a inclusão de efeitos fixos, esta tese de doutorado fornece evidências de que a OMC teve um profundo impacto sobre o comércio internacional. Entretanto, esse impacto ocorreu de forma assimétrica entre os setores, países desenvolvidos e em desenvolvimento, membros e não membros. Considerando as importações agregadas, os países em desenvolvimento foram os mais favorecidos pela atuação da OMC, porém com dados desagregados de produtos primários, têxteis e industrializados, os países desenvolvidos foram os que mais se beneficiaram do aumento do comércio mundial promovido pela OMC. Muito embora as nações desenvolvidas também tiveram seus fluxos de comércio ampliados pela OMC nos setores têxtil e industrial, o maior crescimento ocorreu no setor primário. Além disso, esses países não discriminaram os não membros da instituição. Diferentemente, a abertura comercial dos países em desenvolvimento foi discriminatória e o crescimento do comércio foi observado apenas em produtos primários e industriais, mas em menor magnitude que as nações desenvolvidas. Alternativamente, utilizando o Modelo de Equilíbrio Geral Computável do GTAP, foram avaliados os impactos de uma hipotética conclusão da Rodada de Doha sobre os países desenvolvidos e em desenvolvimento, membros e não membros da OMC. Os resultados sugerem que, ao incorporar a redução de barreiras não tarifárias nas reformas, além das tarifas de importação e subsídios à exportação, os ganhos, em termos de PIB e bem-estar, ampliam-se para os seus membros, sugerindo que seus efeitos são claramente dominantes em relação às tarifas de importação e aos subsídios à exportação. Considerando o cenário de maior liberalização comercial, os países desenvolvidos teriam um crescimento de bem-estar de aproximadamente US$ 572 bilhões, enquanto os em desenvolvimento aumentariam US$ 441 bilhões. O custo de não ser membro da OMC, em termos de bem-estar, pode chegar até US$ 34 bilhões.<br>Using the gravitational model, estimated through the Pseudo Maximum Likelihood of Poisson with the inclusion of fixed effects, this doctoral thesis provides evidence that the WTO had a profound impact on international trade. However, this impact occurred asymmetrically between the developed and developing countries, members and non-members. Considering aggregate imports, developing countries were the ones most benefited by the WTO, but with disaggregated data on primary, textile and industrialized products, developed countries benefited most from the increase in world trade promoted by the WTO. Although developed nations also had their trade flows expanded by the WTO in the textile and industrial sectors, the largest growth occurred in the primary sector. In addition, these countries did not discriminate against non-members of the institution. In contrast, trade liberalization in developing countries was discriminatory and trade growth was observed only in primary and industrial products, but to a lesser extent than developed nations. Also, using the GTAP General Computable Equilibrium Model, the impacts of a hypothetical conclusion of the Doha Round on the developed and developing countries, members and non-members of the WTO, were evaluated. The results suggest that, by incorporating the reduction of non-tariff barriers in the reforms, in addition to import tariffs and export subsidies, gains in terms of GDP and welfare increase for its members, suggesting that its effects Are clearly dominant in relation to import tariffs and export subsidies. Considering the scenario of increased trade liberalization, developed countries would have a welfare growth of approximately US$ 572 billion while developing countries would increase US$ 441 billion. The cost of not being a member of the WTO in terms of welfare can reach up to US$ 34 billion.

In this study cost-benefits problems concerning the knapsack problem of limited resources is studied and how this relates to an attacker perspective when choosing defense strategies. This is accomplished by adopting a cost-benefit method and merging it with game theory. The cost-benefit method chosen for this study is the Analytical Hierarchy Process and from the field of game theory the Bayesian Nash Equilibrium is used. The Analytical Hierarchy Process allows the user to determine internally comparable weights between elements, and to bring in a security dimension to the Analytical Hierarchy Process a sub category consisting of confidentiality, integrity and availability is used. To determine the attacker strategy and, in effect, determine the best defense strategy the Bayesian Nash Equilibrium is used.

The aim of this article is to give a pedagogical introduction to the exact equilibrium and nonequilibrium properties of free fermionic quantum spin chains. In a first part we present in full details the canonical diagonalisation procedure and review quickly the equilibrium dynamical properties. The phase diagram is analysed and possible phase transitions are discussed. The two next chapters are concerned with the effect of aperiodicity and quenched disorder on the critical properties of the quantum chain. The remaining part is devoted to the nonequilibrium dynamical behaviour of such quantum chains relaxing from a nonequilibrium pure initial state. In particular, a special attention is made on the relaxation of transverse magnetization. Two-time linear response functions and correlation functions are also considered, giving insights on the nature of the final nonequilibrium stationnary state. The possibility of aging is also discussed.

Cette thèse s’attache à apporter un éclairage nouveau sur le lien âprement discuté et contesté entre fluctuations de change et croissance économique. Nous avons cherché à rendre compte, sous divers exercices empiriques de l'impact des mésalignements sur la croissance économique d'un grand nombre de pays développés, émergents et en voie de développement depuis les années 1980 jusqu'à la période la plus récente. Les quatre applications empiriques de cette thèse ont ainsi toutes vocation à répondre à cette question, mais sous divers angles de vue.Trois principales contributions émanent de notre thèse. La première réside dans l'identification l'impact des mésalignements de change sur la croissance économique, et de son évolution au cours du temps. Cette thématique a fait l'objet des premier et quatrième chapitres. Nous avons montré que les mésalignements sont néfastes pour la croissance sur l'ensemble de la période étudiée (1980-2010) et que la résorption progressive de leur ampleur s'accompagne d'une réduction de leur impact sur la croissance économique pour les principales économies du G7. Ces deux applications, ont mis en lumière la nécessité de rendre compte de la dynamique des mésalignements au cours du temps et de ne pas se cantonner à une approche statique lorsque l'on étudie le lien mésalignement-croissance. La deuxième contribution de notre thèse réside dans la recherche d'une éventuelle non-linéarité dans le lien mésalignement-croissance. Ainsi, nous avons retenu dans le deuxième chapitre un cadre dans lequel les mésalignements peuvent avoir un impact différencié sur la croissance selon que l'on atteint un certain seuil, c'est-à-dire un certain niveau de sur ou de sous-évaluation. A l'aide d'un modèle à seuil, nous avons mis en lumière l'existence de non linéarités dans la relation entre mésalignement et croissance. Plus spécifiquement, nous avons montré qu'une monnaie sous-évaluée a un impact positif sur la croissance, et ce, jusqu'à un certain seuil. Conformément aux attentes, ce seuil est plus élevé pour notre échantillon de pays asiatiques, mais est en outre de moindre ampleur pour notre échantillon de pays émergents. Nous relions ce résultat au concept de péché originel, qui empêche ces pays d'emprunter dans leur propre monnaie. Bien que l'analyse non-linéaire souligne les effets bénéfiques d'une monnaie mésalignée jusqu'à un certain seuil de sous-évaluation, il convient de souligner que la modélisation retenue n'autorise pas des seuils propres à chaque individu du panel. La troisième contribution de notre thèse réside dans l'analyse de la transmission internationale des mésalignements des devises sur la croissance économique de l’ensemble des pays, développés et émergents. Ainsi, à l’aide d’un modèle GVAR autorisant les interdépendances et, par conséquent, les phénomènes de spillover entre pays, nous étudions les effets de la surévaluation et de la sous-évaluation du dollar, de l’euro et du renminbi sur leur propre croissance mais également celle de leurs partenaires. Les résultats font ressortir le leadership de l’économie américaine dans la croissance mondiale, mais il apparait également que la réduction des déséquilibres mondiaux ne passe pas par un ajustement du dollar<br>This thesis attempts to shed new light on the link hotly debated and contested between exchange rates fluctuations and economic growth. We sought to report under various empirical exercises the impact of misalignments on economic growth in many developed, emerging and developing countries since the 1980s until the most recent period. The four empirical applications of this thesis and all intended to answer this question, but from different angles of view. Three main contributions come from our thesis. The first on is to identify the impact of exchange rate misalignments on economic growth, and its evolution accross time. We have shown that misalignments are harmful for growth throughout the following period (1980-2010) and the gradual reduction of their magnitude is accompanied by a reduction of their impact on economic growth in the major economies G7. The second contribution of this thesis lies in the search for a possible non-linearity in the misalignment-growth nexus. Using a threshold model, we have highlighted the existence of non-linearities in the relationship between misalignments and growth. The third contribution of this thesis lies in the analysis of the international transmission of currency misalignments on economic growth for both developed and emerging markets. Thus, using a GVAR model, we investigate the effects of overvaluation and undervaluation of the dollar, the euro and the renminbi on their own growth, but also that of their partners. The results highlight the leadership of the U.S. economy in global growth, but it also appears that the reduction of global imbalances is not linked to an adjustment of the dollar

A absorção é a etapa determinante da recuperação de acetona no Filter Tow, por reduzir a emissão de acetona e trazer melhorias à economia. Por isso, ela constitui o objeto deste estudo, que inclui desde a revisão dos conceitos fenomenológicos, considerando a escolha do melhor modelo de equilíbrio líquido-vapor, passando pela execução dos balanços coerentes de massa e o estabelecimento da Fotografia da situação original, relatando um caso complexo de transposição de pratos para recheios. Contudo, a operação das colunas de absorção é influenciada por outras variáveis de caráter desconhecido, ruídos em relação à fenomenologia, o que se pretende avaliar, justificando-se desenvolver estudo para avaliar seus efeitos. Com o objetivo geral de otimizar absorção, uma análise estatística foi executada a partir do levantamento de dados operacionais, utilizando todas suas variáveis, sejam as fenomenológicas, como os ruídos, com o objetivo específico de obter modelos empíricos que complementem as simulações fenomenológicas, aumentando sua abrangência. Para a execução da análise estatística, os conjuntos de dados históricos foram levantados e validados pelos balanços coerentes de massa e pela Fotografia, o que tornou possível sua evolução, desde a seleção das variáveis, até estabelecer os modelos de regressão, com os quais pode-se obter um novo modo de controle, que estabiliza a operação, possibilitando a otimização. Em termos ambientais, a utilização destes modelos resulta em redução de até 15% das perdas de acetona para o ambiente, como também de consumo energético, com uma economia da ordem de 1 milhão de reais por ano, sem quaisquer custos adicionais.<br>Absorption is the key step of the acetone recovery at Filter Tow production, for reducing the acetone emission and improving economics. For this reason it is the subject of this study, including the revision of phenomenological concepts, considering the choice of the best vapor liquid equilibrium model, passing by the improvement of coherent mass balances and establishing the Photography of the original situation, detailing a complex case of transposition of sieve trays to structured packing. However, the operation of the absorption columns is influenced by other variables, with unknown impacts, noises in relation to the phenomenology, justifying the development of this study, for evaluating them. With the general objective of optimizing the absorption, a statistical analysis is performed from collecting operating data, considering all variables, phenomenological and noises, with the specific objective of getting empirical models complementing the phenomenological simulations, increasing their comprising. For performing the statistical analysis sets of historical data have been collected and validated by coherent mass balances and the Photography, making possible its evolution, from the selection of the variables till establishing the regression models, and with them getting a new control way, which stabilizes the operation, allowing the optimization. In environmental terms, the use of these models results in up to 15% decrease in acetone losses to the environment, as well as power consumption with a saving of approximately 1 million reais per year, without any additional costs.

La methode proposee consiste a combiner la methode de la surface potentiometrique de bye-lefebvre, une methode de regression non lineaire et une methode de simulation statistique. Etude des equilibres de formation des isopolyanions molybdiques. On propose un mecanisme de type sn2 pour les reactions de decondensation et d'hydrolyse des ions trimolybdiques et tetramolybdiques

Ce travail de thèse présente un dispositif expérimental original permettant la mesure, dans des conditions comparables, des fluctuations de l'aimantation d'un échantillon et de sa réponse à un champ magnétique. Une comparaison quantitative permet, via le théorème de fluctuation-dissipation, une mesure absolue de la température lorsque l'échantillon est à l'équilibre thermodynamique. Pour des systèmes vitreux, la "température effective" ---une extension conservant le formalisme du théorème de fluctuation-dissipation de la température pour les système à faible production d'entropie--- est rendue accessible. Un échantillon "verre de spin" ($CdCr_{1,7}In_{0,3}S_4$) aux propriétés vitreuses étudiées depuis de nombreuses années a permis cette mesure. Le régime fortement vieillissant, non-stationnaire, est étudié; la mesure nécessaire des fluctuations thermiques est très délicates (l'amplitude de ces fluctuations correspond à la réponse de l'échantillon à des variations de l'ordre du millionième du champ magnétique terrestre). <br> Les résultats obtenus montrent en premier lieu une dynamique de quasi-équilibre, confirmant des résultats précédents. Le régime fortement vieillissant est maintenant également atteint. Toutefois, les mesures ne peuvent pas être traduites directement en terme de température effective, car expérimentalement, on observe systématiquement la coexistence d'une dynamique stationnaire et de la dynamique de vieillissement. Une analyse par scaling est proposée pour séparer ces deux contributions. Sous réserve de validité de cette analyse, les mesures confirment alors les principales caractéristiques attendues pour la température effective, et notamment son indépendance en fonction de l'âge du système. <br> Les différents modèles connus ne permettent cependant pas d'expliquer complètement toutes les caractéristiques de la température effective mesurée, certaines d'entre elles paraissant encore antinomiques...

Cette thèse vise à étudier de façon approfondie la dynamique et les déterminants du taux de change. Elle examine également le lien entre déséquilibres internes et externes. Le premier chapitre s'intéresse à l'effet du passage à l'euro sur la vulnérabilité du compte courant à des chocs de demande et de mésalignements de change. Nos résultats montrent qu'avec l'adoption de la monnaie unique, la vulnérabilité du compte courant aux chocs de demande et de mésalignements de change augmente considérablement. Le deuxième chapitre de la thèse analyse la robustesse de l'effet Balassa Samuelson (BS) pour un panel de 38 économies en développement et émergentes sur la période 1980-2016. Nous examinons les versions interne et externe de l'hypothèse BS en nous basant sur cinq mesures différentes de l'effet BS. Nous montrons que la version interne de l'effet BS n'est vérifiée que si le différentiel de productivité du travail entre les secteurs échangeables et non échangeables est utilisé. Nous trouvons également un effet robuste du prix relatif des biens non échangés par rapport aux biens échangés sur le taux de change effectif réel (TCER). Le troisième chapitre étudie les effets non linéaires des infrastructures sur le TCER en estimant un modèle Panel Smooth Transition Regression (PSTR), visant à mettre en avant un impact différencié des infrastructures sur le TCER selon la valeur prise par la variable de transition. Nous considérons trois variables de transition différentes : le stock de télécommunications pour 1000 travailleurs, la Capacité de Production d'Electricité (CPE) pour 1000 travailleurs et la qualité du réseau électrique. Lorsque le réseau n'est pas achevé ou que le stock d'infrastructures est faible, une augmentation des CPE et du stock de télécommunications déprécie le TCER, tandis que la dépréciation supplémentaire est plus faible ou inexistante une fois le réseau établi. Les résultats obtenus sont discutés à la lumière de plusieurs canaux de transmission<br>This thesis aims to study the dynamics and determinants of the exchange rate, paying particular attention to the link between internal and external imbalances. The first chapter examines the effect of the euro adoption on the vulnerability of the current account to demand and exchange rate misalignments shocks. Our results show that, with the adoption of the single currency, the vulnerability of the current account to demand shocks and exchange rate misalignments increases considerably. The second chapter of the thesis provides an in-depth analysis of the robustness of the Balassa Samuelson (BS) effect for a panel of 38 developing and emerging economies over the period 1980-2016. We examine the internal and external versions of the BS hypothesis based on five different measures. We show that the internal version of the BS effect is validated only if the labour productivity differential between tradable and non-tradable sectors is used. We also find a robust effect of the relative price of non-traded to traded goods on the real effective exchange rate (REER). The third chapter studies the non-linear effects of infrastructure on the REER by estimating a Panel Smooth Transition Regression (PSTR) model, aiming to highlight a differentiated impact of infrastructure on the REER depending on the value taken by a transition variable. We consider three different transition variables: the telecommunications stock per 1000 workers, the Electricity Generating Capacity (EGC) per 1000 workers and the quality of the electricity network. When the network is not completed or the infrastructure stock is low, an increase in EGC and telecommunications stock depreciates the REER, while the additional depreciation is lower or non-existent once the network is established. The results obtained are discussed in the light of several transmission channels

Cette étude considère des systèmes où non seulement la structure moléculaire, mais les conditions expérimentales sont impliquées. Les structures chimiques ont été codées par des descripteurs locaux ISIDA MA ou ISIDA CGR, ciblant spécifiquement les centres actifs et leur environnement le plus proche. Les descripteurs locaux ont été combinés avec les paramètres spécifiques des conditions expérimentales, codant ainsi un objet chimique particulier. La méthodologie a été appliquée avec succès pour la modélisation QSPR des paramètres thermodynamiques et cinétiques des interactions intermoléculaires (liaisons halogène et hydrogène), des équilibres tautomères et des réactions chimiques (cycloaddition et SN1). La méthode GTM a été appliquée pour la première fois pour la modélisation et la visualisation de données chimiques mixtes. La méthode sépare avec succès les groupes de données à la fois en raison des structures et des conditions<br>This work describes original approaches for predictive chemoinformatics modeling of molecular interactions and reactions as a function of the structures of interacting partners and of the chemical environment (experimental conditions). Chemical structures have been encoded by local ISIDA MA-based or CGR-based descriptors, specifically targeting the active centers and their closest environment. The local descriptors have been combined with the specific parameters of experimental conditions, thereby encoding a particular chemical object. The methodology has been successfully applied for QSPR modeling of thermodynamic and kinetic parameters of intermolecular interactions (halogen and hydrogen bonds), tautomeric equilibria and chemical reactions (cycloaddition and SN1). GTM method has been applied for the first time for QSPR modeling and visualization of mixed chemical data. This method successfully separates data clusters on account of both chemical structures and experimental conditions

Il riconoscimento facciale è una tecnica di identificazione di una persona tramite l’immagine (fotografica o video) del suo viso, confrontata con un’altra immagine della stessa persona, precedentemente memorizzata e identificata. Il riconoscimento facciale si avvale della biometria e di tecnologie basate su algoritmi complessi e sull’Intelligenza Artificiale (IA). Negli ultimi decenni, grazie alla diffusione della digitalizzazione, è stato possibile raccogliere e incrociare sempre più informazioni (dati e immagini), portando il concetto e l’attività di sorveglianza a livelli inimmaginabili, fino a quando non sono arrivati all’opinione pubblica casi eclatanti, che hanno portato alla luce il livello di sorveglianza digitale praticato dai governi, ma anche da imprese private, rendendo evidente quanto ognuno di noi sia ogni giorno soggetto a una pluralità di sorveglianti. In ambito europeo, soltanto da pochi anni si è cominciato a porre l'attenzione al problema del riconoscimento facciale e alle conseguenze sui diritti delle persone (FRA - European Union Agency for Fundamental Rights, “Facial recognition technology: fundamental rights conside-rations in the context of law enforcement” del 21 novembre 2019). Nella tesi saranno affrontati: i rischi a cui sono sottoposti i diritti delle persone nell’applicazione di questa tecnologia, in rapporto ai potenziali benefici e alla loro legittimità; i vantaggi e i difetti (compresi i bias) dei sistemi di riconoscimento facciale; quali sono gli strumenti a disposizione per produrre normative esaustive e che possano tenere il passo con l’evoluzione intrinseca della tecnologia, anche nel rispetto dei principi che già definiscono il rispetto della privacy e dei dati sensibili.

Il fenomeno dell’apprendimento può essere studiato attraverso metodiche di Meccanica Statistica. A partire dalle Neural Networks è possibile descrivere il problema dell'apprendimento mediante un sistema di spin interagenti. Usando una descrizione all’equilibrio del sistema e sotto opportune condizioni, tale problema si dimostra computazionalmente complesso. Tuttavia, esistono algoritmi euristici in grado di risolvere lo stesso problema efficacemente. Si dimostra che questa apparente inconsistenza è dovuta al fatto che lo spazio delle soluzioni degli algoritmi euristici non coincida con quello atteso all’equilibrio. Utilizzando una distribuzione fuori dall’equilibrio è possibile realizzare l’algoritmo replicated focusing Belief Propagation (rfBP), i cui risultati in termini di performance computazionali e di natura delle soluzioni sono in linea con i risultati degli algoritmi euristici. Questo lavoro evidenzia come l’utilizzo integrato di modelli a Spin-Glass, grafi e Neural Networks siano in grado di creare una base teorica solida per lo sviluppo di algoritmi di machine learning originali e innovativi. Questo lavoro, inoltre, introduce una nuova libreria di C++ ottimizzata per il calcolo parallelo dell’algoritmo rfBP e applica tale algoritmo su dati di Genome Wide Association. Sono stati considerati campioni di genomi del batterio Salmonella, ospitati in diversi animali, ed è stato effettutato il training dell’algoritmo rfBP sull’insorgenza di mutazioni (Single Nucleotide Polymorphism, SNP), nel tentativo di determinare l’animale da cui essi sono stati ospitati. L’obiettivo di questa applicazione è capire come i genomi dei batteri siano influenzati dal proprio ospite animale e se è possibile evidenziare delle caratteristiche che permettano di risalire dalla sequenza di SNPs all’ospite. Questo lavoro mostra che l’algoritmo rfBP produce, su tali sequenze di SNPs, performance comparabili e superiori a quelli ricavati con le più comuni tecniche di Machine Learning.

This thesis concerns the study of complex conformational surfaces and tautomeric equilibria of molecules and molecular complexes by quantum chemical methods and rotational spectroscopy techniques. In particular, the focus of this research is on the effects of substitution and noncovalent interactions in determining the energies and geometries of different conformers, tautomers or molecular complexes. The Free-Jet Absorption Millimeter Wave spectroscopy and the Pulsed-Jet Fourier Transform Microwave spectroscopy have been applied to perform these studies and the obtained results showcase the suitability of these techniques for the study of conformational surfaces and intermolecular interactions. The series of investigations of selected medium-size molecules and complexes have shown how different instrumental setups can be used to obtain a variety of results on molecular properties. The systems studied, include molecules of biological interest such as anethole and molecules of astrophysical interest such as N-methylaminoethanol. Moreover halogenation effects have been investigated on halogen substituted tautomeric systems (5-chlorohydroxypyridine and 6-chlorohydroxypyridine), where it has shown that the position of the inserted halogen atom affects the prototropic equilibrium. As for fluorination effects, interesting results have been achieved investigating some small complexes where a molecule of water is used as a probe to reveal the changes on the electrostatic potential of different fluorinated compounds: 2-fluoropyridine, 3-fluoropyridine and penta-fluoropyridine. While in the case of the molecular complex between water and 2-fluoropyridine and 3-fluoropyridine the geometry of the complex with one water molecule is analogous to that of pyridine with the water molecule linked to the pyridine nitrogen, the case of pentafluoropyridine reveals the effect of perfluorination and the water oxygen points towards the positive center of the pyridine ring. Additional molecular adducts with a molecule of water have been analyzed (benzylamine-water and acrylic acid-water) in order to reveal the stabilizing driving forces that characterize these complexes.

This thesis concerns the study of complex conformational surfaces and tautomeric equilibria of molecules and molecular complexes by quantum chemical methods and rotational spectroscopy techniques. In particular, the focus of this research is on the effects of substitution and noncovalent interactions in determining the energies and geometries of different conformers, tautomers or molecular complexes. The Free-Jet Absorption Millimeter Wave spectroscopy and the Pulsed-Jet Fourier Transform Microwave spectroscopy have been applied to perform these studies and the obtained results showcase the suitability of these techniques for the study of conformational surfaces and intermolecular interactions. The series of investigations of selected medium-size molecules and complexes have shown how different instrumental setups can be used to obtain a variety of results on molecular properties. The systems studied, include molecules of biological interest such as anethole and molecules of astrophysical interest such as N-methylaminoethanol. Moreover halogenation effects have been investigated on halogen substituted tautomeric systems (5-chlorohydroxypyridine and 6-chlorohydroxypyridine), where it has shown that the position of the inserted halogen atom affects the prototropic equilibrium. As for fluorination effects, interesting results have been achieved investigating some small complexes where a molecule of water is used as a probe to reveal the changes on the electrostatic potential of different fluorinated compounds: 2-fluoropyridine, 3-fluoropyridine and penta-fluoropyridine. While in the case of the molecular complex between water and 2-fluoropyridine and 3-fluoropyridine the geometry of the complex with one water molecule is analogous to that of pyridine with the water molecule linked to the pyridine nitrogen, the case of pentafluoropyridine reveals the effect of perfluorination and the water oxygen points towards the positive center of the pyridine ring. Additional molecular adducts with a molecule of water have been analyzed (benzylamine-water and acrylic acid-water) in order to reveal the stabilizing driving forces that characterize these complexes.

Every day we share our personal information through digital systems which are constantly exposed to threats. For this reason, security-oriented disciplines of signal processing have received increasing attention in the last decades: multimedia forensics, digital watermarking, biometrics, network monitoring, steganography and steganalysis are just a few examples. Even though each of these fields has its own peculiarities, they all have to deal with a common problem: the presence of one or more adversaries aiming at making the system fail. Adversarial Signal Processing lays the basis of a general theory that takes into account the impact that the presence of an adversary has on the design of effective signal processing tools. By focusing on the application side of Adversarial Signal Processing, namely adversarial information fusion in distributed sensor networks, and adopting a game-theoretic approach, this thesis contributes to the above mission by addressing four issues. First, we address decision fusion in distributed sensor networks by developing a novel soft isolation defense scheme that protects the network from adversaries, specifically, Byzantines. Second, we develop an optimum decision fusion strategy in the presence of Byzantines. In the next step, we propose a technique to reduce the complexity of the optimum fusion by relying on a novel nearly-optimum message passing algorithm based on factor graphs. Finally, we introduce a defense mechanism to protect decentralized networks running consensus algorithm against data falsification attacks.

The knowledge of phase equilibrium is essential for the planning and realisation of separation processes in chemical engineering. In this work an equipment for measurement of precise isothermal vapour–liquid equilibria (VLE) using the dynamic method was developed. The pool of experimental data for cyclohexylamine was extended significantly. Isothermal VLE were measured in 3 binary and 4 ternary systems, liquid-liquid equilibria (LLE) were measured in 4 ternary systems and in one quarternary system, in each case for two temperatures, whereas in 2 ternary systems and in the quarternary system even liquid-liquid-liquid equilibria (LLLE) occur. Furthermore, activity coefficients at infinite dilution in 4 binary systems and excess molar volumes in 7 binary systems have been estimated. Binary VLE and LLE data of the components water, octane, cyclohexylamine and aniline of this work and data from literature were fitted with the activity coefficient models NRTL and UNIQUAC, as well as with the equations of state Elliott-Suresh-Donohue (ESD) and Perturbed-Chain-Statistical Associating Fluid Theory (PC-SAFT) which contain both a term to consider explicit hydrogen bonds. In addition, the predictive capabilities of the equations of state (EoS) were investigated. With parameters obtained by simultaneous fitting of VLE and, if available, LLE data similar results with the models NRTL and UNIQUAC could be obtained. Each time the deviations for the vapour pressure were lower than 3 % and lower than 2 % in vapour phase composition. The deviations, in three out of the six systems for vapour pressure and vapour phase composition, were larger with the ESD-EoS than with the activity coefficient models. NRTL, UNIQUAC and ESD delivered similar results with the simultaneously fitted parameters for the LLE, whereas the deviations were lower than 5 %. Comparable results were delivered by the ESD-EoS and PC-SAFT for the fitting and the prediction in the investigated binary systems. Also a fitting for NRTL, UNIQUAC and ESD was carried out, but only to one data set. The intention was to show the effect of parameterization on prediction in ternary systems. Predictions were made for VLE and LLE in ternary systems of the above mentioned components, solely with interaction parameters fitted to binary data. For the models NRTL, UNIQUAC und ESD predictions of simultaneously and separately fitted parameters are presented. It is shown that with parameters simultaneously fitted to several data sets significantly better results could be obtained compared to the parameters separately fitted to a single data set. Additionally, for the equations of state ESD and PC-SAFT predictions for the LL(L)E in ternary systems are compared, but here only with separately fitted parameters. For three out of the four investigated ternary systems a too large miscibility gap is calculated with the models NRTL, UNIQUAC and ESD. In the system water+octane+aniline good results could be obtained for the prediction of the LLLE. In summary the equations of state deliver similar results. In the systems water+octane+CHA and octane+CHA+aniline also too large two phase regions were delivered. Better predictions could be obtained in the systems water+octane+aniline and water+CHA+aniline. The forecasts of the VLE in the ternary systems are good with the simultaneously fitted parameters. The deviations for the vapour phase compositions are as for the vapour pressures under 6 %. Larger deviations occur for the system water+octane+aniline only. As evaluation result for the thermodynamic models can be mentioned that the activity coefficient models NRTL and UNIQUAC deliver somewhat better results for the fitting of the binary data than the equations of state ESD and PC-SAFT however, with a larger number of adjustable parameters. The prediction of the VLE is satisfactorily in the ternary systems and with similar quality of all considered models. Larger deviations occur for the prediction of the LL(L)E in the ternary systems. The results of the ESD-EoS were, with one exception, each time better than those of the activity coefficient models. There is no significant difference between the prediction of the ternary systems for the ESD-EoS and the PC-SAFT.

This thesis examines the measurement, applications and properties of consumer inflation expectations in the context of eight European Union countries: France, Germany, the UK, Spain, Italy, Belgium, the Netherlands and Sweden. The data proceed mainly from the European Commission's Consumer Survey and are qualitative in nature, therefore requiring quantification prior to use. This study first seeks to determine the optimal quantification methodology among a set of approaches spanning three traditions, associated with Carlson-Parkin (1975), Pesaran (1984) and Seitz (1988). The success of a quantification methodology is assessed on the basis of its ability to match quantitative expectations data and on its behaviour in an important economic application, namely the modelling of wages for our sample countries. The wage equation developed here draws on the theoretical background of the staggered contracts and the wage bargaining literature, and controls carefully for inflation expectations and institutional variables. The Carlson-Parkin variation proposed in Curto Millet (2004) was found to be the most satisfactory. This being established, the wage equations are used to test the hypothesis that the advent of EMU generated an increase in labour market flexibility, which would be reflected in structural breaks. The hypothesis is essentially rejected. Finally, the properties of inflation expectations and perceptions themselves are examined, especially in the context of EMU. Both the rational expectations and rational perceptions hypotheses are rejected. Popular expectations mechanisms, such as the "rule-of-thumb" model or Akerlof et al.'s (2000) "near-rationality hypothesis" are similarly unsupported. On the other hand, evidence is found for the transmission of expert forecasts to consumer expectations in the case of the UK, as in Carroll's (2003) model. The distribution of consumer expectations and perceptions is also considered, showing a tendency for gradual (as in Mankiw and Reis, 2002) but non-rational adjustment. Expectations formation is further shown to have important qualitative features.

This thesis explores various economic environments where the structure of social interactions across individuals determines outcomes. In the first chapter, I study mutual insurance arrangements restricted on a social network. I test the network-based sharing rules on data from Bolivian communities, and I argue that this framework provides a reinterpretation of the standard risk sharing results, predicting household heterogeneity in response to income shocks. In the second paper, I study individual and collective behavior in coordination games where information is dispersed through a network. I show how changes in the distribution of connectivities in the population affect the types of coordination in equilibrium as well as the probability of success. In the third chapter, I explore a framework of learning and turnover in the labor market. I show that positive assortative matching (PAM) extends beyond the stable environment of Eeckhout & Weng (2010) to a situation of residual uncertainty that exhibits periods of unlearning. I also extend this setting to allow for career concerns and I show that PAM can only be sustained under strong assumptions.<br>Esta tesis explora diversos entornos económicos en los que la estructura de las interacciones sociales entre los individuos determina los distintos resultados. En el primer capítulo, se estudia acuerdos de seguro mutuo restringidos en una red social. Utilizo datos de comunidades bolivianas para medir las predicciones teóricas y encuentro que los intercambios observados entre los hogares coinciden con la regla de reparto basada en la red obtenida por la teoría. Sostengo que este marco ofrece una reinterpretación de los resultados estándar de distribución de riesgos, prediciendo heterogeneidad entre los hogares en respuesta a los shocks de ingresos. En el segundo artículo, estudio el comportamiento individual y colectivo en juegos de coordinación, donde la información se dispersa a través de una red. Demuestro cómo los cambios en la distribución de las conectividades de la población afectan a los tipos de coordinación en equilibrio, así como la probabilidad de éxito. En el tercer capítulo, analizo un marco de aprendizaje y cambio de personal en el mercado de trabajo. Muestro que emparejamiento selectivo positivo (PAM) se extiende más allá del entorno estable de Eeckhout y Weng (2010) a una situación de incertidumbre residual que exhibe períodos de des-aprendizaje. También extiendo esta configuración para permitir elementos de career concerns y muestro que el equilibrio de PAM sólo puede sostenerse bajo fuertes supuestos.

La qualité des eaux-de-vie est un paramètre associé à la composition en composés volatils d’arôme. Cette composition résulte de la combinaison de différents facteurs dont la nature et le traitement des matières premières, mais surtout des transformations ayant lieu lors des phases de fermentation, distillation et, dans la plupart de cas, vieillissement.La distillation est une opération de séparation pratiquée depuis des millénaires, avec une technologie assez mature. Cependant, dans le domaine des eaux-de-vie, elle s’appuie essentiellement sur des connaissances empiriques. L’objectif de ce doctorat fut de contribuer à une meilleure compréhension du comportement des composés volatils d’arôme au cours de différents modes de distillation et de fournir des bases scientifiques à la conduite des unités par le biais de modules de simulation. L’attention a été portée sur la distillation d’Armagnac et de Calvados dans des colonnes multiétagées en régime stationnaire.Les modules de simulation ont été construits avec le logiciel ProSimPlus®. La première partie des travaux a été consacrée à l’acquisition de données d’équilibre liquide-vapeur des composés volatils d’arôme en milieu hydroalcoolique pour l’identification du modèle NRTL, en suivant trois approches complémentaires : recherche dans la littérature, détermination expérimentale et prédiction théorique avec les modèles UNIFAC et COSMO. Grâce à la connaissance acquise sur les volatilités relatives par rapport à l’éthanol et à l’eau, les composés volatils d’arôme ont pu être classés en trois groupes : composés légers, composés intermédiaires et composés lourds. La deuxième partie des travaux a porté sur la construction et la validation des modules de simulation, après réconciliation des données issues de la caractérisation expérimentale des unités de distillation. Cette investigation démontre que la simulation est un outil d’ingénierie performant dans le domaine des eaux-de-vie. Les résultats de la simulation ont permis d’affiner la classification des composés intermédiaires en trois catégories supplémentaires selon leur profil de concentration dans la colonne et leur taux de récupération dans le distillat. Enfin, cet outil a mis en évidence que certains paramètres opératoires, notamment l’augmentation de la teneur en éthanol du distillat ainsi que l’extraction de queues, favorisent la séparation préférentielle de certaines espèces de volatilité faible ou intermédiaire par rapport à l’éthanol<br>The quality of spirits is a parameter related to the composition of volatile aroma compounds. This composition results from the combined production process of raw material extraction, subsequent fermentation, distillation and, in many cases, ageing.Distillation is a very old and the most important industrial separation technology. However, in spirits production, this operation relies essentially on empirical knowledge. The aim of this PhD was to contribute to a better understanding of the volatile aroma compounds behaviour in spirits distillation and to provide a scientific basis for the process through computer simulation. The study was focused on Armagnac and Calvados production by continuous multistage distillation.The simulation modules were built using the software ProSimPlus®. The first part of this research was dedicated to the acquisition of vapor-liquid equilibrium data of the volatile aroma compounds in ethanol-water solutions, in order to estimate the binary interaction parameters of the NRTL model.Three complementary approaches of data acquisition were used: literature compilation, experimental measurements and predictions with UNIFAC and COSMO models.According to their relative volatilities with respect to ethanol and water, the volatile aroma compounds can be classified in three groups: light compounds, intermediary compounds and heavy compounds. The second part of this research dealt with the creation and validation of simulation modules, by using reconciled experimental data from the distillation units. The results prove that simulation is a powerful tool in spirits distillation. The simulation data enables a more precise classification of the intermediary compounds in three categories, by considering their composition profiles in the distillation column and their recovery ratios from feed to distillate. Finally, the analysis of some operating parameters, including ethanol concentration in the distillate as well as tails extractions, demonstrates that the distillate composition can be modified by virtue of a selective separation of intermediary and heavy compounds with respect to ethanol

Lors de l'extraction de l'uranium par lixiviation acide, AREVA fait face à des phénomènes transitoires de précipitation de phases mal cristallisées entrainant un colmatage des installations. Les analyses de ces précipités ont mis en évidence la formation d'un solide jaune minoritaire et d'un blanc majoritaire composé de sulfate de calcium et d'hydroxysulfate d'aluminium. Afin de comprendre les phénomènes menant à la précipitation et pour prévoir, éviter ou limiter leur apparition, les travaux de thèse ont consisté en l'étude expérimentale des équilibres solides-liquide du système complexe Al–Fe–K–P–S–H2O (± Ca et Mg) en milieu acide à 25°C, avec pour objectif l'identification des solides susceptibles d'apparaître en conditions industrielles. Les résultats permettront ainsi de compléter les bases de données thermodynamiques utilisées pour modéliser le comportement global du milieu lors des opérations. Après la mise au point de techniques analytiques appropriées, le travail s'est porté sur la délimitation des équilibres liquide-solides du système relatif au précipité blanc et particulièrement sur l'analyse des ternaires impliquant les hydroxysulfates d'aluminium. Le colmatage se produisant durant la phase d'acidification, l'évolution de la précipitation de ces hydroxysulfates en fonction du pH a été étudiée, afin de caractériser les solides formés en présence de cations minoritaires (Na+, K+, Mg2+, Ca2+) et de définir leurs constantes de solubilités à partir d'un modèle de calcul des coefficients d'activités des ions en solution. Des tests dynamiques sur colonne à partir de minerai naturel ont également été effectués et comparés aux résultats statiques<br>During the uranium extraction by acid leaching, AREVA observed the precipitation of not well crystallized solid phases, leading to the clogging of various equipment. The analyses of these precipitates highlighted the formation of a minor yellow precipitate and a major white precipitate containing calcium sulphate and aluminium hydroxisulphate. To understand the phenomena leading to the precipitation and to predict, prevent or at least limit their formation, this thesis work consisted of the solid-liquid equilibria experimental study of the Al–Fe–K–P–S–H2O (± Ca and Mg) system in an acidic environment at 25°C, with the identification of solid phases which may appear in natural ore as the major goal. The results could complete the thermodynamic database used to model global behaviour of the environment during acid mining. Based on the observed precipitates, two quaternary systems were defined, such as the H2O-Al3+, Ca2+ // O2-, SO42- system. After the development of appropriate analytical techniques, the work focused on the delimitation of the liquid-solid equilibria of the system based on the white precipitate and particularly on the analysis of the ternaries involving aluminium hydroxisulphates. As clogging occurs during acidification, the hydroxisulphate precipitation depending on the pH was studied in the presence of minority cations (Na+, K+, Mg2+, Ca2+), in order to characterise the solid phases which were formed, and to define their solubility constants. For the solubility constant determination, a calculation model of the ion activity coefficients in solution was used. A dynamic survey on a column containing natural ore was done and compared to static results

Research Doctorate - Doctor of Philosophy (PhD)<br>This work presents a new development in the analysis of equilibrium investigations using spectrophotometric titrations to now allow the analysis of a number of titrations simultaneously. We describe this as the 'second order globalisation of the analysis'. The background of equilibrium analysis, particularly spectrophotometric analysis, leading up to second order global analysis is traced in Chapter 1. Spectrophotometric analysis was first used for very simple systems measured at one wavelength; this we have termed 'zeroth order analysis'. 'First order global analysis', the analysis of single titrations measured at many wavelengths, is the present standard of spectrophotometric analysis, proving more robust and useful for complex systems. Second order global analysis is shown here to allow the analysis of even more complicated equilibria and to overcome many of the difficulties found in first order global analysis. A computer program, EQUISPEC, was written to perform second order globalisation. The theory behind and characteristics of this program are described in Chapter 2 and its success on real equilibria is demonstrated in Chapter 3. It is shown to overcome the linear dependence of individual titrations (Zn²⁺-phen), to allow improved definition of minor species (Eu³⁺-phen, Eu³⁺-FNAC, and Eu³⁺-PDA), and to result in reduced uncertainties in the refined equilibrium constants (Cu²⁺-dien, Cu²⁺-N₃phenol, and nitr). Further 2^nd order global analysis proved invaluable in the investigation of the interaction of DTPA with In³⁺. This equilibrium was quantified in a series of competition experiments using HBED as an auxiliary coloured ligand. EQUISPEC can also perform first order global analysis in the usual way and this is done in Chapter 4 to examine the equilibria of SM³⁺ and DTPA versus a bifunctional DTPA analogue of relevance to nuclear medicine. It was also adapted and applied to the investigation of the high spin - low spin equilibrium for an Fe(III) complex. The instrumentation used for acquisition of the spectrophotometric data is described in Chapter 5. This Chapter also contains the description of some synthetic work, as well as the crystal structure of [Eu(FNAC)₂(TOPO)₂(NO₃)]. Fluroescence titrations are described and discussed in the context of seeking a greater understanding of the complexation of Eu³⁺ by ligands of relevance to fluroimmunoassay procedures.

Two new apparati have been developed to measure solid-liquid and liquid-liquid equilibria via a synthetic visual method by determination of thermal signatures. One apparatus adopts a technique of using Peltier modules for cooling, and the other is a well-known design that uses a cryogenic fluid in a thermostatted glass cell for cooling of the sample. The Peltier design is for small sample volumes, with a 10 cm3 aluminium equilibrium cell and has a minimum operating temperature of 253.15 K. The glass design is developed to complement the Peltier and has a larger volume of 140 cm3 and a minimum operating temperature of 223.15 K. Both apparati have been semi-automated in order to increase the accuracy and improve the efficiency of data measurements. Therefore the experimenter no longer has to wait for many hours for the determination of equilibrium. This was done by incorporating software, which was specially designed for the apparati using Labview8TM, for controlling the cooling and heating rates. The uncertainty of the temperature measurements was found to be ±0.03 K for the Peltier apparatus and ±0.02 K for the Glass apparatus. Liquid-liquid equilibria data has also been measured on the Peltier apparatus, to demonstrate its versatility. This was done using a digital camera, controlled through the Labview software to identify cloud points. The results have been found to be comparable with literature values. For solid-liquid equilibria new systems of n-alkyl carboxylic acid binary mixtures have also been measured: heptanoic acid + butyric acid and heptanoic acid + hexanoic acid. These systems were measured using both apparati and both systems exhibited eutectic behaviour. All eutectic temperatures were measured on the Glass apparatus. Experimental data for these systems was modelled using the local composition models: Wilson, NRTL and UNIQUAC models. The NRTL model was found to give the best results for both systems with root mean square deviations (RMSD) of 2.16 K and 1.27 K and absolute average deviations (AAD) of 0.61 K and 0.49 K, between temperature measurements of this work and those calculated from the models, for the heptanoic acid + butyric acid and heptanoic acid + hexanoic acid systems, respectively.<br>Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.