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Das, Jitesh Chandra. "Correlations of certain physico - chemical properties of some ternary liquid mixtures with selected parameters of corresponding pure components." Thesis, University of North Bengal, 1989. http://hdl.handle.net/123456789/714.
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Lutsyk, V. I., and A. E. Zelenaya. "Ternary Systems for the Liquid Immiscibility Gap Technology." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35368.
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The computer models for T-x-y diagrams with the mono- and invariant monotectic equilibrium, and monovariant syntectic equilibrium by means of kinematical simulation of phase regions boundaries are considered. The effect of syntectic equilibrium changing for monotectic one is investigated with the material balances visualization.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35368
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Siddons, Daniel James. "Synthetic routes to binary and ternary nitrides." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363637.
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Kurosawa, Izumi. "Solid-Liquid Equilibrium in Multi Solute Systems." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4993.
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Solid-liquid equilibrium in isomorphous amino acid systems has been investigated as a model for systems that form solid solutions. Solid- and liquid-phase compositions in L-valine + L-leucine, L-valine + L-isoleucine, and L-isoleucine + L-valine in water were measured over the entire range of solid composition, and it was shown (from mass balance and phase rule considerations) that these systems form solid solutions. The solid- phases resulting from isothermal and cooling crystallization experiments were also investigated using powder x-ray diffractometry which showed that homogeneous solid solutions could only be obtained in cooling crystallization experiments, whereas isothermal experiments generally produced inhomogeneous solids. This suggests that data reported in the literature from isothermal experiments may not represent true equilibrium values. Solid-phase activity coefficients were estimated using binary and ternary equilibrium data and the UNIFAC-Kuramochi model for liquid-phase nonidealities. The solid phases in the three systems investigated exhibited significant nonidealities that were correlated using the Margules model. The model parameters exhibited a linear relationship with the ratio of binary solubilities of the two solutes. Such simple relationship may be advantageous when solid-liquid equilibrium of thermally unstable solutes or components with unknown physical properties are crystallized.
5
Galand, Quentin. "Experimental investigation of the diffusive properties of ternary liquid systems." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209626.
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A fundamental step in the further developments of comprehensive modelling of the diffusive processes in liquids requires the possibility of obtaining reliable and accurate experimental data of the diffusion and thermodiffusion coefficients of multicomponent liquid systems. In the present work, we perform an experimental investigation of the diffusive properties of binary and ternary liquid systems. Two experimental techniques, the ‘Open Ended Capillary’ technique and the ‘Transient Interferometric Technique’ have been developed. Those techniques have been used for the experimental characterization of several systems composed of 1,2, 3,4-Tetrahydrnaphtalene, Isobutylbenzene and Dodecane at ambient temperature. Those particular species were selected as a simplified multicomponent system modelling the fluids contained in natural crude oils reservoirs. <p>For each of these techniques, experimental set-ups were designed, implemented and calibrated. The procedures for identifying the ternary diffusion coefficients from the measured compositions fields were studied in details. <p>The Open Ended Capillary Technique was applied under gravity condition to study isothermal diffusion binary and ternary systems. Difficulties related to a new procedure for interpreting the data collected at short times of the experiments are highlighted and its implication in the generalization of the technique for the study of multicomponent systems is discussed.<p>The Transient Interferometric Technique was used to perform an experimental study of three binary systems under gravity conditions. It was also applied for the investigation of ternary systems under microgravity condition in the frame of the DSC on SODI experiment, which took place aboard the International Space Station in 2011. The experimental results are reported and the analysis of the accuracy of the technique is presented. The TIT is the first technique ever providing accurate experimental measurements of the complete set of diffusion and thermodiffusion coefficients for ternary liquid systems.<p><br>Doctorat en Sciences de l'ingénieur<br>info:eu-repo/semantics/nonPublished
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Swisher, Mathew M. "Representing liquid-vapor equilibria of Ternary systems using neural networks." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/97856.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 77-78).<br>We develop a method based on neural networks for efficiently interpolating equations of state (EOS) for liquid-vapor equilibria of ternary mixtures. We investigate the performance of neural networks both when experimental data are available and when only simulation data are available. Simulation data are obtained from Gibbs Ensemble Monte Carlo simulations, using the TraPPE-EH molecular model. Our investigation uses the mixture of carbon dioxide, methane, and ethane as a validation example, for which experimental data exist. Analysis of the error in a neural-network-generated liquid-vapor coexistence curve shows that the resulting interpolation is robust and accurate, even in the case where the network is trained on a few data points. We use this observation to construct a methodology for accurately locating liquid-vapor equilibria of ternary mixures wihout using any experimetnal data.<br>by Mathew M. Swisher.<br>S.M.
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Ivanov, Dimitry A. "Investigation of a ternary liquid mixture by the light scattering technique." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=98015216X.
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Taylor, Donald Fulton. "Measurement of binary phase equilibria and ternary/quaternary gas antisolvent (GAS) system measurement and analysis." Thesis, Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-07112004-194307/unrestricted/taylor%5Fonald%5Ff%5F200407%5FMS.pdf.
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Thesis (M.S.)--School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2005. Directed by Charles Eckert.<br>Charles Eckert, Committee Chair ; Amyn Teja, Committee Member ; Pete Ludovice, Committee Member. Includes bibliographical references.
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Luna, Fabio. "Drying of Multicomponent Liquid Films." Doctoral thesis, KTH, Chemical Engineering and Technology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3778.
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<p>The convective drying of thin layers of multicomponentliquid mixtures into an inert gas, and the influence ofdifferent process controlling mechanisms on drying selectivityis studied. Drying experiments under gas-phase-controlledconditions are performed by low intensity evaporation, fromfree liquid surfaces, of ternary mixtures without non-volatilesolutes. Liquid-side-controlled experiments are carried out bydrying a multicomponent polymeric solution containing twovolatile components, one non-volatile polymer and an optionalnonvolatile softening substance.</p><p>Mathematical models to describe gas- andliquid-side-controlled drying based on interactive diffusion inboth liquid and gas phases as the main mechanisms for masstransfer are developed. For gas-phase-controlled drying, astability analysis of the ordinary differential equations thatdescribes the evaporation process is performed. Isothermal andnon-isothermal drying processes are considered in batch andcontinuous modes. The mathematical model to describe thecomposition profiles during batch drying of the polymeric film,considering liquid resistance, is solved numerically. Due tothe lack of experimental data, properties for this polymericsystem are estimated by using established methods. Ananalytical solution of the diffusion equation, by assuming anisothermal drying process and a constant matrix ofmulticomponent diffusion coefficients is developed. For thecontinuous case, liquid-side resistance is studied by modellingevaporation of a multicomponent falling liquid film into aninert gas including indirect heating.</p><p>The results of the gas-phase-controlled model are in goodagreement with experimental results. For the polymeric film,the agreement is only qualitative since the model does notaccount for a membrane that develops on the film surface. Thestability analysis permits the prediction of trajectories andfinal state of a liquid mixture in a gas-phase-controlleddrying process. For isothermal evaporation of ternary mixturesinto pure gas, the solutions are trajectories in the phaseplane represented by a triangular diagram of compositions. Thepredicted ternary dynamic azeotropic points are unstable orsaddle. On the other hand, binary azeotropes are stable whenthe combination of the selectivities of the correspondingcomponents is negative. In addition, pure component singularpoints are stable when they are contained within theirrespective isolated negative selectivity zones. Undernon-isothermal conditions, maximum temperature valuescharacterise stable azeotropes. Incremental loading of the gaswith one or more of the components leads to a node-saddlebifurcation, where a saddle azeotrope and a stable azeotropecoalesce and disappear. For continuous drying, the singularpoints are infinite and represent dynamic equilibrium pointswhose stability is mainly dependent on the ratio of inletgas-to-liquid flow rates. As long as the process isgas-phasecontrolled, these results also apply to a porous solidcontaining a liquid mixture.</p><p>In general, liquid-side control makes the drying processless selective but it is difficult to maintain this conditionduring the whole process. Under the influence of its owndynamics, a process starting as liquid-side-controlled tendstowards a gas-phase-controlled process. The presence ofnon-volatile components and indirect heating may delay thisdevelopment. Considering the evolution of the processcontrolling steps and its influence on selectivity, a modelaimed at describing the complete trajectory of a drying orevaporation process must include the coexistence of allrelevant mechanisms.</p><p><b>Keywords:</b>ternary mixture, falling film, diffusionequation, gas-phase control, liquid-phase control, selectivity,stability analysis, polymeric solution, evaporation, azeotrope,batch drying, continuous drying.</p>
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Clements, Patricia J. "Critical point behaviour in binary and ternary liquid mixtures with particular reference to rheological and interfacial properties in model mixtures for microemulsions." Thesis, University of Sheffield, 1997. http://etheses.whiterose.ac.uk/10187/.
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The phase behaviour, rheological effects and interfacial properties of binary and ternary liquid mixtures have been studied near critical points. In particular, measurements have been made of the viscosity-at the bulk macroscopic level by capillary viscometry and at the microscopic level by fluorescence depolarisatiorr-and of critical-point wetting and adsorptiorr-at the solid-liquid interface using evanescent-wave-generated fluorescence spectroscopy and at the liquid-vapour interface using specular neutron reflection. The systems investigated have been mostly alkane + perfluoroalkane mixtures or 2-butoxyethanol + H20 or D20 mixtures, although in some cases hexamethyldisiloxane, propanenitrile and perfluorooctyloctane have also been the components of mixtures. The main outcomes of this study are: • Macroscopic viscosity: The divergence to infinity in the shear viscosity of hexane + perfluorohexane at the critical endpoint for approach along the path of constant critical composition both from the single phase and along both limbs of the coexistence curve is described well using the Renormalisation Group Theory critical exponent y = 0.04. The correlation length amplitude obtained by fitting the sheargradient dependence of the viscosity is ~o = (S.S±l.S) A. • Microscopic viscosity: The product of the rotational correlation time and the temperature 'tR"T, often taken as a measure of the microscopic viscosity, exhibits an anomaly as the critical point is approached as a function of temperature. This anomaly mirrors that in the macroscopic viscosity for some fluorescent dye probes, but for others the anomaly is in the opposite sense indicating that other effects such as solvent structure must playa part in the near-critical behaviour of'tR·T. • Critical-point wetting at the solid-liquid interface: The wetting transition temperature has been identified for heptane + perfluorohexane at the quartz-liquid interface from fluorescence lifetime measurements of a probe. The wetting layer is of the same composition as the bulk heptane-rich phase and the transition is tentatively identified as first-order. • Adsorption and wetting at the liquid-vapour interface: The surface structure of several mixtures has been determined by neutron reflection. The results are in general agreement with the expectations of critical-point wetting and adsorption. The surface is complex and in some mixtures an oscillatory scattering length density profile through the interface is required to model the reflectivity data. • Ternary mixtures: The phase behaviour of three mixtures exhibiting tunnel phase behaviour has been studied experimentally and various characteristics of the shape of the twmel identified. A theoretical study on one of the mixtures predicts the drop in temperature for the locus of maximum phase separation temperatures which is observed experimentally.
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Henriques, Eduardo Fontes. "Um modelo para o estudo do efeito da polidispersividade sobre as fases nemáticas em sistemas micelares." Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/43/43133/tde-19062015-154820/.
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Consideramos um modelo de interações quadrupolares entre micelas capaz de explicar a ocorrência de fases nemáticas biaxiais. Micelas uniaxiais de formatos variáveis, representando a polidispersividade do sistema, são incluídas. O modelo apresenta uma fase nemática calamítica separada de uma fase discótica por uma fase biaxial, segundo resultados de campo médio e de simulações de Monte Carlo.<br>We consider a model of quadrupole interactions between micelles which is able to explain the occurrence of biaxial phases. Uniaxial micelles of variable shape, representing system polydispersity, are included. The model displays a calamitic nematic phase separated from a discotic phase by a biaxial phase, according to mean-field and Monte Carlo simulation results.
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Watari, Raku. "Electrochemical behavior of a liquid tin electrode in molten ternary salt electrolyte containing sodium chloride, aluminum chloride, and tin chloride." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104316.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2016.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 33-34).<br>One of the key limitations in the wide-scale adoption of mature renewable energy technologies is the lack of grid-level energy storage solutions. One important figure of merit in these battery systems is a high rate capability to match fluctuating demands for electricity. Molten salt batteries are an attractive option for stationary storage due to fast kinetics and good cycling capability, but high temperatures (>300 °C) limit available materials. In this thesis, the molten NaCl-AlCl3-SnCl2 electrolyte and liquid Sn electrode couple at 250 °C is investigated as part of the potential cell Na I NaCl-AlCl 3-SnCl2 I Sn for a lower temperature molten salt battery. An electrochemical study of the kinetics in the molten salt electrolyte and at the liquid Sn electrode-electrolyte interface is conducted using cyclic voltammetry and the galvanostatic pulse method. The liquid metal electrode is found to have suitably fast kinetics with an exchange current density of 92 mA/cm2. Parameters for a new Na+ conducting membrane are proposed, requiring an ionic conductivity of 0.056 S/cm, which would allow for a hypothetical Na I NaCl-AlC 3-SnCl2 I Sn battery to operate with an energy efficiency of 70%.<br>by Raku Watari.<br>S.B.
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Grunert, Tommy [Verfasser], Sabine [Akademischer Betreuer] Enders, and Hans-Jörg [Akademischer Betreuer] Bart. "Theoretical and experimental studies on interfacial properties of ternary liquid mixtures / Tommy Grunert. Gutachter: Sabine Enders ; Hans-Jörg Bart. Betreuer: Sabine Enders." Berlin : Technische Universität Berlin, 2014. http://d-nb.info/1067386556/34.
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Kipruto, Eric Wekesa. "APPLICATION OF POLARITY MODELS TO CHARACTERIZING THE REVERSED-PHASE LIQUID CHROMATOGRAPHY SEPARATION OF CHIRAL STEROID ISOMER PAIRS EMPLOYING VARIOUS TERNARY MOBILE PHASES." Cleveland State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=csu1631533233544729.
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González, Segredo Nélido Jesús. "Lattice-Boltzmann and lattice-gas simulations of binary immiscible and ternary amphiphilic fluids in two and three dimensions." Doctoral thesis, Universitat Autònoma de Barcelona, 2004. http://hdl.handle.net/10803/3368.
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Passos, Helena Isabel Sousa. "Development and characterization of new extraction platforms using ionic-liquid-based aqueous biphasic systems." Doctoral thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/22448.
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Doutoramento em Engenharia Química - Bioengenharia<br>Devido às suas propriedades únicas, sendo a sua capacidade de tailoring uma
das mais importantes, os líquidos iónicos são atualmente considerados
potenciais substitutos dos solventes orgânicos voláteis comumente utilizados
pela indústria, o que levou a uma investigação crescente da sua aplicação em
diversas áreas. Contudo, para além da utilização de líquidos iónicos
hidrofóbicos na formação de sistemas bifásicos com água e/ou em meios
aquosos, na última década, introduziram-se os líquidos iónicos hidrofílicos
como constituintes de sistemas aquosos bifásicos – sistemas do tipo líquidolíquido
compostos por duas fases aquosas e mais benignos – conduzindo a
uma melhor performance de extração e seletividade para um vasto número de
compostos. Tendo em conta todas estas vantagens, esta tese tem como
objetivo o estudo científico e tecnológico de sistemas aquosos bifásicos
constituídos por líquidos iónicos, envolvendo o desenvolvimento de novos
processos de separação mais eficientes.
Com o intuito de desenvolver plataformas de extração/separação mais
eficientes, este trabalho inicia-se com o estudo de novos compostos e suas
misturas na formação de sistemas aquosos bifásicos. A caracterização das
propriedades das fases em equilíbrio e a descrição dos mecanismos que
regem a formação destes sistemas, bem como a partição de diversos solutos
entre as fases, são temas abordados no segundo capítulo. Por último, e como
um exemplo de possível aplicação destes novos sistemas, estudou-se a sua
utilização na extração e pré-concentração de compostos que apresentam
riscos para a saúde humana e ambiente.
A elevada versatilidade dos sistemas aquosos bifásicos constituídos por
líquidos iónicos, bem como a sua elevada performance na extração dos mais
diversos compostos, foram aqui demonstrados, confirmando o potencial destes
sistemas como processos de separação alternativos. No entanto, e como
comprovado neste trabalho, ainda é necessário prosseguir com a investigação
em sistemas aquosos bifásicos constituídos por líquidos iónicos,
principalmente visando o seu scale-up e utilização final pela indústria.<br>Due to their unique properties, being one of the most important their tailoring
ability, ionic liquids (ILs) have been investigated in several fields and proposed
as alternatives to hazardous volatile organic compounds commonly used by
industries. In addition to the use of hydrophobic ILs in the formation of biphasic
systems with water and/or in aqueous media, in the past decade, hydrophilic
ILs were introduced as phase-forming components of aqueous biphasic
systems (ABS) – more benign liquid-liquid systems composed of two aqueousrich
phases – able to provide improved extraction performance with increased
selectivity for a large range of compounds. Based on these advantages, this
thesis aims to gather a deeper scientific and technological knowledge on ILbased
ABS, through the development and characterization of novel and more
efficient separation processes.
Aiming at developing ABS with tailored and better extraction performance, this
work starts with a comprehensive investigation on the use of new phaseforming
components and their mixtures, and their impact on the formation of
liquid-liquid systems. The characterization of the properties of the coexisting
phases and the description of the mechanisms which rule the formation of ILbased
ABS, as well as the partition behavior of several solutes between the
phases, are addressed in the second chapter. Finally, the use of these novel
IL-based systems in the extraction and pre-concentration of compounds of
human and environmental concern is addressed as a main example of these
systems applications.
The high versatility of IL-based ABS, as well as their high extraction
performance and selectivity, were here demonstrated, confirming their potential
within separation processes. Nevertheless, and as proved in this work,
additional research on IL-based ABS is still required so that these systems can
be finally scaled-up and used by industries.
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Kuntz, Michael. "Quantifying Isothermal Solidification Kinetics during Transient Liquid Phase Bonding using Differential Scanning Calorimetry." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/890.
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The problem of inaccurate measurement techniques for quantifying isothermal solidification kinetics during transient liquid phase (TLP) bonding in binary and ternary systems; and resulting uncertainty in the accuracy of analytical and numerical models has been addressed by the development of a new technique using differential scanning calorimetry (DSC). This has enabled characterization of the process kinetics in binary and ternary solid/liquid diffusion couples resulting in advancement of the fundamental theoretical understanding of the mechanics of isothermal solidification. The progress of isothermal solidification was determined by measuring the fraction of liquid remaining after an isothermal hold period of varying length. A 'TLP half sample', or a solid/liquid diffusion couple was setup in the sample crucible of a DSC enabling measurement of the heat flow relative to a reference crucible containing a mass of base metal. A comparison of the endotherm from melting of an interlayer with the exotherm from solidification of the residual liquid gives the fraction of liquid remaining. The Ag-Cu and Ag-Au-Cu systems were employed in this study. Metallurgical techniques were used to compliment the DSC results. The effects of sample geometry on the DSC trace have been characterized. The initial interlayer composition, the heating rate, the reference crucible contents, and the base metal coating must be considered in development of the experimental parameters. Furthermore, the effects of heat conduction into the base metal, baseline shift across the initial melting endotherm, and the exclusion of primary solidification upon cooling combine to systematically reduce the measured fraction of liquid remaining. These effects have been quantified using a modified temperature program, and corrected using a universal factor. A comparison of the experimental results with the predictions of various analytical solutions for isothermal solidification reveals that the moving interface solution can accurately predict the interface kinetics given accurate diffusion data. The DSC method has been used to quantify the process kinetics of isothermal solidification in a ternary alloy system, with results compared to a finite difference model for interface motion. The DSC results show a linear relationship between the interface position and the square root of the isothermal hold time. While the numerical simulations do not agree well with the experimental interface kinetics due to a lack of accurate thermodynamic data, the model does help develop an understanding of the isothermal solidification mechanics. Compositional shift at the solid/liquid interface has been measured experimentally and compared with predictions. The results show that the direction of tie-line shift can be predicted using numerical techniques. Furthermore, tie-line shift has been observed in the DSC results. This study has shown that DSC is an accurate and valuable tool in the development of parameters for processes employing isothermal solidification, such as TLP bonding.
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Ribeiro, Valeria Santana. "Predição de equilibrio liquido-vapor de sistemas multicomponentes atraves de redes neurais." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267336.
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Orientadores: Roger Josef Zemp, Ana Maria Frattini Fileti<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica<br>Made available in DSpace on 2018-08-04T03:59:01Z (GMT). No. of bitstreams: 1
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Previous issue date: 2005<br>Resumo: Na literatura são apresentados vários modelos termodinâmicos para o ajuste de dados de equilíbrio líquido-vapor (ELV) multicomponentes. Entretanto, devido à complexidade destes modelos termodinâmicos para interpolar dados para pressões onde dados experimentais não são disponíveis, foi proposto o uso das Redes Neurais Artificiais. Inicialmente a resolução de equações de equilíbrio líquido-vapor foi feita através de cálculos do ponto de Bolha T para o sistema ternário 2-buranol 2-butanona- água a fin de se obter uma grande quantidade de dados para serem usados nos treinamentos das redes. O modelo termodinâmico usado na representação da fase líquida foi NRTL (Non-Random-Two-Liquid). Estes dados foram então usados para treinar e testar os modelos de redes neurais, e nós verificamos que as redes neurais foram capazes de descrever o comportamento de equilíbrio com pequenos desvios nas composições preditas para o vapor em sistemas isobáricos. Um modelo neural foi então desenvolvido no MATLAB para fazer predição das propriedades termodinâmicas para o sistema 2-butanol-2-btanona-água, usando dados em diferentes pressões para treinas a rede, e predizer a composição de vapor e temperaturas em pressões na usadas no treinamento das redes. Como esperado, resultados muito pobres foram obtidos quando dois conjuntos de dados isobáricos usados para predizer o comportamento de ELV em uma pressão intermediária... Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital<br>Abstract: Many thermodynamic models for the data correlation of multicomponent liquid-vapor equilibrium (LVE) can be found in the literature. However, due the difficulty of these thermodynamic models to interpolate data at pressures where experimental data is not available, the use of Artificial Neural Networks was considered. Initially the resolution of liquid-vapour equilibrium equations was made through calculations of the bubble-point T for the ternary system 2-butanol / 2-butanone / water in order to get a reasonable amount of data to be used in the training of the networks. The thermodynamic model used in the representation of the liquid phase was NRTL (Non-Random-Two-Liquid). These data were then used to train and test neural network models, and we verified that the neural nerworks were capable of describing the equilibrium behavior with small deviations in predicted vapor composition, for isobaric systems. A neural model was then developed in MATLAB to make predictions of thermodynamic properties for the 2-butanol / 2-butanone / water system, using data at different pressures to train the network, and predict vapor composition and temperature at pressures nor used to train the network. As expected, a very poor result was obtained when two isobaric sets of data were used to predict LVE behavior at an intermediate pressure... Note: The complete abstract is available with the full electronic digital thesis or dissertations<br>Mestrado<br>Sistemas de Processos Quimicos e Informatica<br>Mestre em Engenharia Química
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NUNES, Juliana Cordeiro. "Estudo experimental e modelagem para o equilíbrio líquido-líquido em sistemas ternários e pseudo-quaternários de biodiesel etílico e metílico de girassol (Helianthus annus l.)." Universidade Federal de Campina Grande, 2017. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1470.
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Previous issue date: 2017-09-15<br>A pesquisa por fontes alternativas de energia tem sido cada vez mais intensa. Nesse contexto, surge o biodiesel, biocombustível que apresenta as seguintes características: emite menos poluente que o diesel de petróleo, biodegradável, renovável, não tóxico, dentre outras. O biodiesel é produzido através da reação de transesterificação, onde o óleo vegetal ou a gordura animal reage com álcool de cadeia curta na presença de um catalisador. O óleo de girassol é uma oleaginosa com potencial utilização para a produção do biodiesel, visto que pode ser plantada no Nordeste brasileiro no período chuvoso. Após a reação de transesterificação, o produto reacional contém impurezas que precisam ser retiradas e, para isso, devem ser realizadas a lavagem e a purificação do produto reacional. Para realizar a lavagem e a purificação é necessário conhecer o equilíbrio líquido-líquido de misturas formadas por água, glicerina, biodiesel e álcool. E, para isso, pode ser preciso ter posse dos dados termodinâmicos. O objetivo deste trabalho é realizar o estudo termodinâmico sobre o equilíbrio de fases de sistemas ternários (biodiesel de girassol – álcool – glicerina) e pseudoquaternários (biodiesel de girassol – álcool – glicerina – água/ácido diluído). Para isso, foi utilizado o método da minimização da energia de Gibbs, à temperatura e pressão constantes. Para representar as fases formadas em cada sistema, foi empregado o modelo UNIQUAC. Os parâmetros de interação binária entre os compostos foram estimados através do método dos mínimos quadrados. O sistema ternário formado por biodiesel metílico de girassol – metanol – glicerina, foi analisado à 25ºC, 35ºC e 45ºC e foi observado que o efeito da temperatura foi pouco expressivo, havendo uma pequena redução da região de imiscibilidade à 45ºC. Foram estudados os sistemas pseudo-quaternários formados por biodiesel metílico de girassol – metanol – glicerina – água destilada/ácido sulfúrico diluído, o sistema ternário de biodiesel etílico de girassol – etanol – glicerina e também os sistemas pseudo-quaternários formados por biodiesel etílico de girassol – etanol – glicerina – água destilada/ácido sulfúrico diluído. Em todos os sistemas pseudo- quaternários foi observado que a presença de água/ácido diluído: aumenta a região de separação de fases, não havendo alteração expressiva no comportamento da curva ao aumentar a quantidade de água destilada/ácido diluído de 50% para 75% em relação à massa da glicerina; e diminui a solubilidade do biodiesel na fase rica em glicerina+água destilada/ácido diluído. Na modelagem termodinâmica do ELL, os dados experimentais foram comparados com os valores calculados pelo modelo UNIQUAC, onde obteve-se uma boa concordância entre os dados experimentais e os valores calculados, uma vez que o maior desvio apresentado foi de 0,27%. Isso mostra que, no estudo no ELL dos
sistemas analisados, podem ser utilizados os parâmetros calculados. Observou-se que é
satisfatório o uso do modelo UNIQUAC para tais sistemas.<br>The search for alternative sources of energy has been increasingly intense. In this context, it appears the biodiesel, biofuel that has the following characteristics: it emits less pollutant than petroleum diesel, biodegradable, renewable, non-toxic, among others. biodiesel is produced through the transesterification reaction, where vegetable oil or animal fat reacts with short chain alcohol in the presence of a catalyst. Sunflower oil is an oleaginous with potential use for the production of biodiesel, since it can be planted in the Brazilian Northeast during the rainy season. After the transesterification reaction, the reaction product contains impurities that need to be removed and, for this, the wash and purification of the reaction product must be carried out. To carry out the washing and the purification it is necessary to know the liquid-liquid equilibrium of mixtures formed by water, glycerine, biodiesel and alcohol. And for that, it may be necessary to have possession of the thermodynamic data. The objective of this work is to perform the thermodynamic study on the phase equilibrium of ternary systems (sunflower biodiesel - alcohol - glycerin) and pseudo - quaternaries (sunflower biodiesel - glycerine - water / diluted acid). The Gibbs energy minimization method was used at constants temperature and pressure. To represent the phases formed in each system, the UNIQUAC model was used. The parameters of binary interaction between the compounds were estimated using the least squares method. The ternary system formed by sunflower methyl biodiesel - methanol - glycerin was analyzed at 25ºC, 35ºC and 45ºC and it was observed that the effect of the temperature was not very expressive, with a small reduction of the region of immiscibility at 45ºC. We studied the pseudo quaternary systems formed by sunflower methyl biodiesel - methanol - glycerol - distilled water / diluted sulfuric acid, the ternary l system of ethyl biodiesel of sunflower - ethanol – glycerin and also the pseudo - quaternary systems formed by sunflower ethyl biodiesel - ethanol - glycerin - distilled water / diluted sulfuric acid. In all pseudo-quaternary systems it was observed that the presence of diluted water / diluted acid: increases the region of phase separation, with no significant change in the behavior of the curve by increasing the amount of distilled water / diluted acid from 50% to 75% relative to the glycerol mass; and decreases the solubility of biodiesel in the rich phase at glycerin + distilled water / dilute acid. In the thermodynamic modeling of the LLE, the experimental data were compared with the values calculated by the UNIQUAC model, where a good agreement was obtained between the experimental data and the calculated values, since the largest deviation was 0.27%. This shows that, in the LLE study of the analyzed systems, the calculated parameters can be used. It was observed that the use of the UNIQUAC model for such systems is satisfactory.
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Lopreato, Luiz Guilherme Roquette. "Desenvolvimento de modelo neural a partir de sistemas binarios para predição de equilibrio liquido-vapor de sistemas ternarios." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267023.
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Orientador: Ana Maria Frattini Fileti<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica<br>Made available in DSpace on 2018-08-13T14:31:54Z (GMT). No. of bitstreams: 1
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Previous issue date: 2009<br>Resumo: A aplicação de redes neurais artificiais (RNA) na solução de problemas de equilíbrio líquido-vapor de misturas multicomponentes apresenta resultados consistentes com valores experimentais observados. Sua principal vantagem, frente às abordagens tradicionais, reside na capacidade de modelar o sistema em equilíbrio sem a necessidade da definição prévia de um modelo específico, tarefa muitas vezes árdua. No presente trabalho utilizam-se dados de três sistemas binários para o treinamento de modelo neural com o objetivo de predizer o equilíbrio de sistema ternário em condições isobáricas. O algoritmo de treinamento utilizado foi o de Levenberg-Marquardt com Regularização Bayesiana, implementado por meio do software MATLAB. A estrutura de rede que apresentou os melhores resultados contém as frações molares dos três componentes na fase líquida, como parâmetros de entrada, e as frações molares dos três componentes na fase vapor e a temperatura como parâmetros de saída. O escalonamento dos dados foi realizado entre 0 e 1, sendo utilizada a função de ativação sigmoidal na camada oculta da rede e a função linear na camada de saída. O desempenho dos modelos foi analisado a partir dos coeficientes de correlação, coeficientes regressão linear, resíduos entre os valores experimentais e preditos, além da raiz dos desvios quadráticos médios (RMSD). O principal sistema estudado foi Acetona-Metanol-Água, sendo os conceitos desenvolvidos extrapolados para os sistemas polares Metanol-Etanol-Água, Metanol-2-Propanol-Água e para o sistema apolar Benzeno-Ciclohexano-Hexano. Os resultados obtidos indicam que a predição de equilíbrio através do modelo neural se mostra consistente com os dados experimentais e as predições realizadas via modelo UNIQUAC. Destaca-se que a construção do modelo neural baseia-se no uso de dados de sistemas binários para a predição de sistemas ternários, enquanto que o modelo UNIQUAC utiliza parâmetros regredidos a partir de dados experimentais para o equilíbrio ternário. Dessa forma, os conceitos utilizados nas duas modelagens são bastante distinto sendo, à priori, favoráveis ao modelo termodinâmico, fato não condizente com os resultados obtidos no presente estudo.<br>Abstract: Modeling multicomponent vapor-liquid equilibrium (VLE) by means of Artificial Neural Networks (ANN) showed to be able to successfully reproduce observed experimental points. The main advantage of this approach, regards to the traditional approaches, resides in the capacity to modeling the equilibrium condition without the necessity of the prior
definition of a specific model, which is a task very often strenuous. In the present work data of three binary systems were used to training a neural network model with the objective to predict the equilibrium of a ternary system at isobaric conditions. The training algorithm used was Levenberg-Marquardt with Bayesian Regularization, implemented through the software MATLAB. The best network structure contains the molar fractions of three components in the liquid phase, as input parameters, and the molar fractions of three components at vapor phase besides the temperature as the output parameters. The data normalization was carried out in the interval between 0 and 1. The sigmoid activation function was used in the hidden layer and linear function was used in the calculations of the exit layer. The performance of the models was analyzed from the coefficients of correlation, linear regression coefficients, residues between the experimental and predicted values, besides the root of the quadratic middle diversions (RMSD). The principal system studied was Methanol-Acetone-Water, being the developed concepts extrapolated to the
polar systems Ethanol-Methanol-Water, Methanol-2-propanol-Water and to the nonpolar system Benzene-Cyclohexane-Hexane. Results presented indicate that vapor-liquid equilibrium prediction through neural network is consistent with experimental data and UNIQUAC model predictions. Moreover, when comparing the ANN model with the thermodynamic model it is important to notice that the first model uses binary systems to
predict ternary system equilibrium, whereas the thermodynamic model uses parameters obtained from experimental ternary data regressions. Thus, the concepts used in both models are quite different, being favorable to the thermodynamic model. Even so the ANN model showed to be very reliable, in the present study.<br>Mestrado<br>Sistemas de Processos Quimicos e Informatica<br>Mestre em Engenharia Química
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Moghaddam, Amir. "Dynamics of transformation and fragmentation of composite liquid nano-particles." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/31776/1/Amir_Moghaddam_Thesis.pdf.
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Recent research on particle size distributions and particle concentrations near a busy road cannot be explained by the conventional mechanisms for particle evolution of combustion aerosols. Specifically they appear to be inadequate to explain the experimental observations of particle transformation and the evolution of the total number concentration. This resulted in the development of a new mechanism based on their thermal fragmentation, for the evolution of combustion aerosol nano-particles. A complex and comprehensive pattern of evolution of combustion aerosols, involving particle fragmentation, was then proposed and justified. In that model it was suggested that thermal fragmentation occurs in aggregates of primary particles each of which contains a solid graphite/carbon core surrounded by volatile molecules bonded to the core by strong covalent bonds. Due to the presence of strong covalent bonds between the core and the volatile (frill) molecules, such primary composite particles can be regarded as solid, despite the presence of significant (possibly, dominant) volatile component. Fragmentation occurs when weak van der Waals forces between such primary particles are overcome by their thermal (Brownian) motion. In this work, the accepted concept of thermal fragmentation is advanced to determine whether fragmentation is likely in liquid composite nano-particles. It has been demonstrated that at least at some stages of evolution, combustion aerosols contain a large number of composite liquid particles containing presumably several components such as water, oil, volatile compounds, and minerals. It is possible that such composite liquid particles may also experience thermal fragmentation and thus contribute to, for example, the evolution of the total number concentration as a function of distance from the source. Therefore, the aim of this project is to examine theoretically the possibility of thermal fragmentation of composite liquid nano-particles consisting of immiscible liquid v components. The specific focus is on ternary systems which include two immiscible liquid droplets surrounded by another medium (e.g., air). The analysis shows that three different structures are possible, the complete encapsulation of one liquid by the other, partial encapsulation of the two liquids in a composite particle, and the two droplets separated from each other. The probability of thermal fragmentation of two coagulated liquid droplets is discussed and examined for different volumes of the immiscible fluids in a composite liquid particle and their surface and interfacial tensions through the determination of the Gibbs free energy difference between the coagulated and fragmented states, and comparison of this energy difference with the typical thermal energy kT. The analysis reveals that fragmentation was found to be much more likely for a partially encapsulated particle than a completely encapsulated particle. In particular, it was found that thermal fragmentation was much more likely when the volume ratio of the two liquid droplets that constitute the composite particle are very different. Conversely, when the two liquid droplets are of similar volumes, the probability of thermal fragmentation is small. It is also demonstrated that the Gibbs free energy difference between the coagulated and fragmented states is not the only important factor determining the probability of thermal fragmentation of composite liquid particles. The second essential factor is the actual structure of the composite particle. It is shown that the probability of thermal fragmentation is also strongly dependent on the distance that each of the liquid droplets should travel to reach the fragmented state. In particular, if this distance is larger than the mean free path for the considered droplets in the air, the probability of thermal fragmentation should be negligible. In particular, it follows form here that fragmentation of the composite particle in the state with complete encapsulation is highly unlikely because of the larger distance that the two droplets must travel in order to separate. The analysis of composite liquid particles with the interfacial parameters that are expected in combustion aerosols demonstrates that thermal fragmentation of these vi particles may occur, and this mechanism may play a role in the evolution of combustion aerosols. Conditions for thermal fragmentation to play a significant role (for aerosol particles other than those from motor vehicle exhaust) are determined and examined theoretically. Conditions for spontaneous transformation between the states of composite particles with complete and partial encapsulation are also examined, demonstrating the possibility of such transformation in combustion aerosols. Indeed it was shown that for some typical components found in aerosols that transformation could take place on time scales less than 20 s. The analysis showed that factors that influenced surface and interfacial tension played an important role in this transformation process. It is suggested that such transformation may, for example, result in a delayed evaporation of composite particles with significant water component, leading to observable effects in evolution of combustion aerosols (including possible local humidity maximums near a source, such as a busy road). The obtained results will be important for further development and understanding of aerosol physics and technologies, including combustion aerosols and their evolution near a source.
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Hund-Huart, Muriel. "Etude des transferts interfaciaux en extraction liquide-liquide sous champ électrique." Paris, ENMP, 1988. http://tel.archives-ouvertes.fr/tel-00845221.
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L'étude expérimentale du transfert de matière est réalisée pour 3 systèmes ternaires mettant en jeu principalement des molécules plutôt que des ions. Deux phénomènes sont observés: un effet électrostatique (orientation des molécules) et un effet électrodynamique (modification de la tension interfaciale). Un contacteur à électrode externe, soumis à des oscillations forcées est utilisé pour l'extraction de l'acide acétique. Lorsque la fréquence des oscillations est égale à la fréquence de résonance naturelle des gouttes on observe une diminution de la vitesse de chute et une augmentation du coefficient de transfert. La taille des gouttes a aussi une influence.
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SOLASTIOUK, GALIVEL FRANCINE. "Equilibres liquide-vapeur des systemes propane-methanol et propane-methanol-dioxyde de carbone : mesures et representations." Paris, ENMP, 1988. http://www.theses.fr/1988ENMP0103.
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Gamero, Rafael. "Transport Coefficients during Drying of Solids containing Multicomponent Mixtures." Doctoral thesis, KTH, Teknisk strömningslära, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-28897.
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This study investigated the transport coefficients involved in mass and heat transfer during the drying of a porous solid partially saturated with multicomponent mixtures. It included the coefficients governing liquid transport through the solid, the matrix of multicomponent diffusion coefficients in the liquid phase, and the effective thermal conductivity. As it is not possible to determine these coefficients by theoretical considerations alone and considerable experimental work is required to determine them in a broad range of process conditions, the principle of this study has been the use of mathematical models complemented with some empirical parameters. These empirical parameters were determined by comparison between measurements in specially designed experiments and the results of mathematical models that describe the process. In addition, the application of the multicomponent diffusion coefficients is described in two cases where liquid diffusion is important: convective evaporation of a multicomponent stationary liquid film and a falling film. To study liquid transport through the solid, isothermal drying experiments were performed to determine the transient composition profiles and total liquid content of sand samples wetted with ternary liquid mixtures with different initial compositions and temperatures. A mathematical model including mass transfer by capillary movement of the liquid and interactive diffusion in both the gas and liquid phases was developed. To simulate the capillary movement of liquid mixtures, parameters experimentally determined for single liquids were weighed according to liquid composition. A fairly good agreement between theoretical and experimental liquid composition profiles was obtained considering that axial dispersion was included in the model. To study the matrix of multicomponent diffusion coefficients in the liquid phase, the redistribution of liquid composition in a partially filled tube exposed to a longitudinal temperature gradient was analysed. Experimental work was carried out using two main ternary mixtures with different initial compositions and temperature gradients. Experimental data were compared with the results of a theoretical model that describes the steady-state liquid composition distribution in a partially filled non-isothermal tube to find the empirical exponent that modifies the matrix of thermodynamic factors. Correlations for the exponents as a function of temperature were determined for each particular multicomponent mixture. The effective thermal conductivity of a porous solid containing multicomponent liquid mixtures was studied by measuring the liquid composition, liquid content and temperature distributions in a cylindrical sample dried by convection from the open upper side and heated by contact with a hot source at the bottom side. Simulations performed at a quasi steady state were compared with experiments to estimate the adjusting geometric parameter of Krischer’s model for effective thermal conductivity, which includes the contribution of the evaporation-diffusion-condensation mechanism. The results revealed that a resistance corresponding to a parallel arrangement between the phases seems to dominate in this case. In the study of the convective drying of a multicomponent stationary liquid film, the equations describing interactive mass transfer were decoupled by a similarity transformation and solved simultaneously with a conduction equation by the method of variable separation. Variations of physical properties along the process trajectory were taken into account by a stepwise application of the solution in time intervals with averaged coefficients from previous time steps. Despite simplifications, the analytical solution gives a good insight into the selectivity of the drying process and is computationally fast. On the other hand, numerical simulations of the convective evaporation of the multicomponent falling liquid film into an inert gas with a co-current flow arrangement of the phases almost always revealed a transition from liquid-phase-controlled conditions to a process in which neither the gas nor the liquid completely controls the evaporation. The results obtained in this work would be useful in implementing models to improve the design, process exploration and optimisation of dryers by incorporating the solid-side effects to describe the drying of liquid mixtures along the whole process.<br>QC 20110124
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Yang, Huaiyu. "Investigations intothe crystallization of butyl paraben." Licentiate thesis, KTH, Teknisk strömningslära, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-34051.
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In thisproject, solubility of butyl paraben in 7 puresolvents and 5 ethanol aqueous solvents has been determined at from 1 ℃to 50 ℃. Thermodynamic properties of butyl paraben have been measured by DifferentialScanning Calorimetey. Relationship between molar solubility of butyl paraben in6 pure solvents and thermodynamic properties has been analyzed. Thisrelationship suggests a method of estimating activity of solute at equilibrium fromcombining solubility data with DSC measurements. Then, activity coefficient accordingto the solubility at different temperatures can be estimated. Duringthe solubility measurements in ethanol aqueous solvents, it is found that whenbutyl paraben is added into aqueous solutions with certain proportion ethanol,solutions separates into two immiscible liquid layers in equilibrium. Water andethanol are primary in top layer, while the butyl paraben is primary in bottomlayer, but the solution turns to cloudy when two layers of solution are mixed. Theaim of this work was to present the phase behaviour of liquid-liquid-phaseseparation for (butyl paraben + water + ethanol) ternary system from 1 ℃ to 50 ℃at atmospheric pressure. Thearea of liquid-liquid-phase separation region in the ternary phase diagram increaseswith the increasing temperature from 10 ℃to 50 ℃. In thisstudy, more than several hundreds of nucleation experiments of butyl paraben havebeen investigated in ethyl acetate, propanol, acetone and 90% ethanol aqueoussolution. Induction time of butyl paraben has been determined at 3 differentsupersaturation levels in these solvents, respectively. Free energy ofnucleation, solid-liquid interfacial energy, and nuclei critical radius havebeen determined according to the classical nucleation theory. Statistical analysis ofinduction time reveals that the nucleation is a stochastic process with widevariation even at the same experiment condition. Butyl paraben nucleates most difficultlyin 90 % ethanol than in other 3 solvents, and most easily in acetone. The interfacialenergy of butyl paraben in these solvents tends to increasing with decreasemole fraction solubility in these solvents. Coolingcrystallizations with different proportions of butyl paraben, water and ethanolhave been observed by Focused Beam Reflectance Method, Parallel VirtualMachine, and On-line Infrared. The FBRM, IR curves and the PVM photos show someof the solutions appeared liquid-liquid phase separation during coolingcrystallization process. The results suggest that if solutions went throughliquid-liquid phase separation region during the cooling crystallizationprocess the distribution of crystals crystal was poor. Droplets from solutions withsame proportion butyl paraben but different proportions of water and ethanolhave been observed under microscope. Induction time of the droplets has been determinedunder the room temperature. Droplets from top layer or bottom layer of solutionwith liquid-liquid phase separation on small glass or plastic plates were alsoobserved under microscope. The microscope photos show that the opposite flows ofcloudy solution on the glass and the plastic plate before nucleation. The resultsof the cooling and evaporation crystallization experiments both revealed thatnucleation would be prevented by the liquid-liquid phase separation.<br>QC 20110630
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Neyt, Jean-Claude. "Calcul de la tension interfaciale de mélanges gaz / eau, gaz / huile et huile / eau par simulation moléculaire." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2013. http://tel.archives-ouvertes.fr/tel-00962483.
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La prédiction de valeurs de tension interfaciale des fluides est capitale dans de nombreuses applications industrielles. Les techniques de simulation moléculaire et l'évolution rapide des moyens de calcul intensif permettent depuis quelques années de prédire des valeurs de tension interfaciale pour des systèmes complexes. Des travaux concernant des équilibres liquide / vapeur des corps purs SO2, O2, N2 et Ar montrent que les modèles choisi pour chaque molécule peuvent influencer la qualité des prédictions de tension interfaciale. Des simulations d'équilibres gaz acide / alcane de type CO2 / n-butane, CO2 / n-décane et H2S / n-pentane ont ensuite été réalisées. Elles ont mis en évidence l'efficacité des méthodes de simulation de type Monte Carlo pour la prédiction des tensions interfaciales pour de tels systèmes. L'étude de systèmes ternaires H2O / N2+CH4 et H2O / CO2+H2S a par ailleurs montré que le recourt à la dynamique moléculaire pouvait faciliter l'équilibration des systèmes simulés, rendant plus efficace la prédiction des tensions interfaciales. L'étude d'équilibres liquide / vapeur de saumures de chlorure de sodium a permis de mettre en évidence l'efficacité de certains potentiels non-polarisables pour la prédiction de l'évolution de la tension interfaciale avec la molarité de sel. Les modèles polarisables de type core-shell choisis ne permettent de prédire ni les masses volumiques, ni les tensions interfaciales. Enfin, l'étude d'équilibres eau / alcane en présence de sel ou de méthanol a montré que les méthodes de dynamique moléculaire permettaient de prédire quantitativement des valeurs de tension interfaciale pour ce type d'interface. L'effet de l'alcool abaissant la tension interfaciale a bien été observé, tout comme son placement préférentiel à l'interface.
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Dablé, Pierre Jean-Marie Richard. "Etude thermodynamique de la solubilité du platine et du rhodium dans les oxydes liquides." Grenoble INPG, 1996. http://www.theses.fr/1996INPG0137.
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Les platinoides dont sont issus le platine et le rhodium presentent des caracteres particuliers qui font d'eux, des indicateurs geochimiques. Ces elements par leur presence dans des roches, peuvent fournir des indications sur les conditions de leur mise en place au cours du processus magmatique. C'est sur cette base, que de nombreuses etudes sont entreprises pour etablir les parametres susceptibles de controler ce phenomene. Dans le but d'obtenir des informations d'ordre general, nous avons etudie dans le cas de bains d'oxydes simples cao-al#2o#3-sio#2, l'influence de la composition du bain, et de la phase metallique sur la solubilite de ces metaux en fonction de la pression partielle d'oxygene. Deux techniques ont ete utilisees dans cette etude, a savoir: l'equilibre triphasique, metal/bain d'oxydes/gaz et la chronopotentiometrie. De cette etude, nous avons pu mettre en evidence la passivation des phases metalliques, etablir la speciation des elements etudies ainsi que les diagrammes de predominance. Les speciations en fonction du potentiel croissant d'oxygene etablies sont pour le platine, pt/pt#2#+/pt#4#+/pt#6#+ et pour le rhodium, rh/rh#2#+/rh#3#+ et rh#4#+. La phase metallique de platine se passive par la formation a l'interface des oxydes pto et pto#2 selon les pressions partielles d'oxygene et par rho dans le cas du rhodium. La formation d'un spinelle pt#2o#3rho a la surface de l'alliage de pt/rh a de meme ete mise en evidence
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Kotchi, Kouadio Pierre. "Contribution à l'étude thermodynamique des liquides métalliques à fortes interactions." Aix-Marseille 1, 1986. http://www.theses.fr/1986AIX11056.
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Mesures, par calorimetrie de reaction directe, des enthalpies integrales et partielles de formation des systemes pb-se, sn-se et pb-se-sn. Determination des diagrammes de phases, des enthalpies de formation et de fusion des composes intermetalliques. Analyse du comportement thermodynamique de formation des liquides ternaires pb-se-sn a partir des parametres d'interactions binaires
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PELENC, DENIS. "Elaboration par epitaxie en phase liquide et caracterisation de couches monocristallines de yag dope : realisation de lasers guide d'onde neodyme et ytterbium a faibles seuils." Grenoble 1, 1993. http://www.theses.fr/1993GRE10171.
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Dans le cadre des recherches sur des dispositifs laser compacts pouvant etre pompes par diodes, ce memoire decrit le developpement d'une nouvelle technique d'elaboration de lasers guides d'onde, l'epitaxie en phase liquide. Cette technique a ete appliquee a la croissance de couches minces monocristallines de yag dope neodyme et ytterbium sur des substrats de yag non dope. Afin d'obtenir des guides de bonne qualite, nous avons defini les conditions de croissance des couches et montre l'interet de la croissance d'une surcouche de confinement. Deux co-dopages ont ete etudies en supplement a l'ion actif: gallium pour controler l'indice optique des couches, lutetium pour controler leur parametre cristallin. La determination du coefficient de segregation des divers dopants a requis le developpement d'un modele qui prend en compte l'evolution des bains au cours du temps. Nous avons mesure l'augmentation d'indice due a chaque dopant et propose un mecanisme expliquant cette augmentation. La caracterisation spectroscopique des couches a indique que les ions actifs ont les memes proprietes que le materiau massif de meme composition. La caracterisation laser a montre des pertes par propagation tres faibles (environ 0,1 db/cm), comparables a celles du materiau massif. Pour la transition laser a 1064 nm du neodyme, nous avons demontre l'effet laser pour une puissance absorbee au seuil de 700 w et mesure un rendement differentiel de 40% en pompage par diode, pour un seuil de 14 mw. Pour des transitions laser quasi-3 niveaux, une diminution significative du seuil par rapport a une configuration non guidee a ete obtenue: a 946 nm dans un guide dope neodyme, a 1029 nm dans un guide dope ytterbium en pompage par barrette de diode 1w. Un rendement differentiel de 80% a egalement ete mesure dans un guide dope ytterbium emettant a 1048 nm
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Huaiyu, Yang. "Crystallization of Parabens : Thermodynamics, Nucleation and Processing." Doctoral thesis, KTH, Teknisk strömningslära, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-122228.
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In this work, the solubility of butyl paraben in 7 pure solvents and in 5 different ethanol-water mixtures has been determined from 1 ˚C to 50 ˚C. The solubility of ethyl paraben and propyl paraben in various solvents has been determined at 10 ˚C. The molar solubility of butyl paraben in pure solvents and its thermodynamic properties, measured by Differential Scanning Calorimetry, have been used to estimate the activity of the pure solid phase, and solution activity coefficients. More than 5000 nucleation experiments of ethyl paraben, propyl paraben and butyl paraben in ethyl acetate, acetone, methanol, ethanol, propanol and 70%, 90% ethanol aqueous solution have been performed. The induction time of each paraben has been determined at three different supersaturation levels in various solvents. The wide variation in induction time reveals the stochastic nature of nucleation. The solid-liquid interfacial energy, free energy of nucleation, nuclei critical radius and pre-exponential factor of parabens in these solvents have been determined according to the classical nucleation theory, and different methods of evaluation are compared. The interfacial energy of parabens in these solvents tends to increase with decreasing mole fraction solubility but the correlation is not very strong. The influence of solvent on nucleation of each paraben and nucleation behavior of parabens in each solvent is discussed. There is a trend in the data that the higher the boiling point of the solvent and the higher the melting point of the solute, the more difficult is the nucleation. This observation is paralleled by the fact that a metastable polymorph has a lower interfacial energy than the stable form, and that a solid compound with a higher melting point appears to have a higher solid-melt and solid-aqueous solution interfacial energy. It has been found that when a paraben is added to aqueous solutions with a certain proportion of ethanol, the solution separates into two immiscible liquid phases in equilibrium. The top layer is water-rich and the bottom layer is paraben-rich. The area in the ternary phase diagram of the liquid-liquid-phase separation region increases with increasing temperature. The area of the liquid-liquid-phase separation region decreases from butyl paraben, propyl paraben to ethyl paraben at the constant temperature. Cooling crystallization of solutions of different proportions of butyl paraben, water and ethanol have been carried out and recorded using the Focused Beam Reflectance Method, Particle Vision and Measurement, and in-situ Infrared Spectroscopy. The FBRM and IR curves and the PVM photos track the appearance of liquid-liquid phase separation and crystallization. The results suggest that the liquid-liquid phase separation has a negative influence on the crystal size distribution. The work illustrates how Process Analytical Technology (PAT) can be used to increase the understanding of complex crystallizations. By cooling crystallization of butyl paraben under conditions of liquid-liquid-phase separation, crystals consisting of a porous layer in between two solid layers have been produced. The outer layers are transparent and compact while the middle layer is full of pores. The thickness of the porous layer can reach more than half of the whole crystal. These sandwich crystals contain only one polymorph as determined by Confocal Raman Microscopy and single crystal X-Ray Diffraction. However, the middle layer material melts at lower temperature than outer layer material.<br><p>QC 20130515</p><br>investigate nucleation and crystallization of drug-like organic molecules
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Nasri, Ridha. "Conception et réalisation d'un adaptateur haute impédance programmable : epplication à la caractérisation de liquides magnétiques." Saint-Etienne, 1994. http://www.theses.fr/1994STET4014.
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Ce travail s'inscrit dans le cadre de la recherche sur les ferrofluides ou liquides magnétiques. Les évolutions, qui peuvent être rapides, des propriétés diélectriques de ces matériaux telles que les changements de phase du liquide porteur, la perte d'homogénéité par formation d'agrégats ou de multicouches nécessitent l'automatisation complète de l'acquisition des mesures. Pour cela, nous avons développé autour d'un analyseur vectoriel, un adaptateur haute impédance programmable en mode shunt fonctionnant dans la gamme 1mhz-10khz. Cette réalisation fait appel à l'électronique haute impédance : résistances de fortes valeurs allant jusqu'à iteraohm et condensateurs à faibles fuites ; ces composants sont commutés par des relais de résistance d'isolement supérieure à 1000teraohms commandes par le bus VXI. Ce spectromètre automatique nous a permis de caractériser, entre 50c et -200c, un ferrofluide ionique composé de particules nanométriques de ferrite de manganèse (Fe2Mno4) dispersées dans le tétrachlorure de carbone (CCL4) utilisé comme liquide porteur. Nous avons ainsi mis en évidence les différentes phases du tétrachlorure de carbone pur à pression atmosphérique (liquide, plastique, solide). Les résultats obtenus sur le ferrofluide, à plusieurs concentrations, ont été analysés selon diverses lois de mélanges théoriques utilisant les constantes diélectriques des deux constituants. Nous avons pu montrer, dans nos conditions expérimentales, la perte de stabilité de ce ferrofluide à basse température et forte concentration
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Silva, Luciana Yumi Akisawa. "Determinação experimental e modelagem termodinamica de dados de equilíbrio de fases de misturas binarias e ternaria contendo acetona, agua e cumeno." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266953.
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Orientador: Maria Alvina Krahenbuhl<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica<br>Made available in DSpace on 2018-08-08T18:45:17Z (GMT). No. of bitstreams: 1
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Previous issue date: 2007<br>Resumo: No projeto de processos de separação é essencial o conhecimento do comportamento das fases que estão em equilíbrio. O presente trabalho consistiu no estudo do equilíbrio de fases de misturas contendo acetona, água e cumeno. Estes componentes são de grande importância para a indústria do fenol. Os componentes água e cumeno são parcialmente miscíveis e na destilação da mistura de acetona, água e cumeno ocorre a formação de três fases (líquido-líquido-vapor), por isso é muito importante a determinação de um único conjunto de parâmetros dos modelos de GE que possa representar adequadamente o equilíbrio líquido-líquido simultaneamente. Determinou-se dados de equilíbrio líquido-vapor dos sistemas acetona + água,acetona + cumeno e acetona + água+ cumeno e dados de equilíbrio líquido-líquido do sistema água + cumeno a 760 mmHg. O Princípio da Máxima Verossimilhança foi utilizado no ajuste dos parâmetros de interação binária dos modelos NRTL e UNIQUAC.Os parâmetros obtidos neste trabalho foram comparados em trabalho anterior,Mafra (2005,) no qual se procedeu ao ajuste de dados ternários de equilíbrio líquido-líquido a 50 °C, e buscou-se o conjunto de parâmetros que melhor representa o equilíbrio líquido-vapor e líquido-líquido simultaneamente. Os resultados obtidos revelaram que o modelo NRTL com parâmetros determinados a partir de dados binários representa satisfatoriamente os equilíbrios líquido-vapor e líquido-líquido de sistemas binários e ternário envolvendo acetona, água e cumeno<br>Abstract: On projecting separation processes it is essential the knowledge of the behavior of the phases in equilibrium. The present work involved the study of the phase equilibrium of mixtures containing acetone, water and cumene, which are very important in the phenol industry. The components water and cumene are partially miscible, and in the distillation of the mixture of acetone, water and cumene occurs the simultaneous formation of three phases, two liquids and one vapor. In such a way this it is important the determination of only one set of parameters for GE models that can represent appropriately the vapor-liquid and liquid-liquid equilibrium. It has been determined vapor-liquid equilibrium data of acetone + water, acetone + cumene and acetone + water -"o cumene systems and liquid-liquid equilibrium data of water + cumene system at 760 mmHg. The Maximum Likelihood Principle was used for the estimation of the interaction parameters for the NRTL and UNIQUAC models. The parameters obtained in this work were compared with the parameters found by Mafra (2005). who realized the reduction of ternary liquid-liquid equilibrium data at 50°C. and it has been analyzed which set of parameters gives the best representation of the vapor-liquid and the liquid-liquid equilibrium simultaneously. The results have shown that the NRTL model with parameters determined by binary data represents properly the vapor-liquid and liquid-liquid equilibrium of binary and ternary systems containing acetone, water and cumene<br>Mestrado<br>Desenvolvimento de Processos Químicos<br>Mestre em Engenharia Química
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Rahal, Naim. "Contribution à l'étude des propriétés d'une solution liquide ternaire au voisinage de la démixtion." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209464.
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Le système ternaire eau-acide butyrique- pentan-2-ol est utilisé comme système modèle pour l’étude de système plus complexe. Ce système est utilisé pour étudier les couplages diffusifs quand les constituants sont distribués sur plusieurs phases. Ses molécules simples permettent de ne pas mettre en avant les effets stériques dus à de longues chaines carbonées ou entropiques dus à des importantes différences de masse moléculaire. <p>Les couplages de la diffusion avec la solubilité permettent d’observer toute une gamme de phénomènes allant de présence de turbidité ou de gouttelettes au sein de la phase aqueuse jusqu’au maintien de gradient de concentration bien au-delà du temps caractéristique de diffusion. Ces différents phénomènes ont été observés grâce à une expérience où l’on superpose deux phases de liquide, l’une de pentan-2-ol pur et l’autre d’un mélange d’eau et d’acide butyrique.<p>La solubilité du système est déterminée par une méthode RMN. Cette technique permet également d’obtenir les variations de l’environnement intermoléculaire avec la composition de la solution et de mettre en évidence des structures au sein du liquide. <p>Enfin les coefficients de self diffusion a été mesuré par méthode DOSY pour les liquides purs, les mélanges binaires et ternaires.<p><br>Doctorat en Sciences de l'ingénieur<br>info:eu-repo/semantics/nonPublished
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Klein, Holger. "Ordre local dans des phases quasicristallines, approximantes et liquides Al-Pd-Mn." Grenoble INPG, 1997. http://www.theses.fr/1997INPG0138.
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Il existe, dans le systeme al-pd-mn, deux phases quasicristallines stables de structures icosaedrique et decagonale ainsi que deux familles de phases approximantes orthorhombiques. Par une etude de ce diagramme de phases nous avons precise les conditions de fabrication de monocristaux de phases approximantes ou quasicristallines. Les domaines d'equilibres entre les differentes phases solides et le liquide ont ete determines. Des structures atomiques de deux phases approximantes ont ete resolues par diffraction de rayons x sur monocristaux. Des clusters icosaedriques centres sur un mn definissent presque entierement leurs structures et jouent un role important dans la deformation plastique de ces phases. Cette derniere a lieu par migration de defauts lineaires qui ne sont pas des dislocations mais des defauts de phasons. La structure de liquides al-(pd)-mn en equilibre avec des phases icosaedrique ou approximantes a ete etudiee par diffusion de neutrons. Des simulations de facteurs de structure a partir de clusters icosaedriques montrent un bon accord avec les resultats experimentaux. Un modele de liquide de spheres dures n'est pas adapte dans ce cas. Les clusters utilises pour ces simulations sont les memes que ceux identifies dans les structures des phases icosaedrique et approximantes. Les distances interatomiques a l'interieur des clusters sont identiques a celles trouvees dans les phases solides. Les alliages al-(pd)-mn presentent une transition diamagnetique - paramagnetique lors de la fusion. La susceptibilite continue d'augmenter en fonction de la temperature dans le liquide. Des comparaisons de mesures de susceptibilite magnetique et de diffusion de neutrons sur differents alliages ont montre que dans le liquide une partie des mn portent un spin. Une interpretation de la correlation entre ordre local icosaedrique et magnetisme est proposee.
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Bellajrou, Raddoine. "Equilibres liquide-vapeur, application au système ternaire NH3-CH3NH2-H2O : tensions de vapeur et cinétiques de décomposition de N2H4, (CH3)2NNH2 et UH25." Lyon 1, 1992. http://www.theses.fr/1992LYO10030.
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Ces travaux ont pour objet l'etude de problemes lies a la synthese et a l'utilisation d'ergols liquides, monomethylhydrazine (mmh) et dimethylhydrazine asymetrique (udmh), utilises dans les moteurs du lanceur ariane. Ils ont necessite la mise au point et la construction d'un dispositif experimental adapte a la determination. * des equations liquide-vapeur dans le systeme ternaire nh#3-ch#3nh#2-h#2o, sous differentes pressions comprises entre 6 et 20 bars, * des tensions de vapeur et des cinetiques de decomposition du n#2h#4. H#2o, de (ch#3)#2nnh#2 et du melange 25/75 (uh25). La caracterisation de l'uh25 est completee par la mesure de la capacite thermique entre 273 et 298 k et de l'enthalpie d'exces a 298 k
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Al-Brasi, Enteisar. "The growth and characterization of films of noble metal nanocrystals and inorganic semiconductors at the interface of two immiscible liquids." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/the-growth-and-characterization-of-films-of-noble-metal-nanocrystals-and-inorganic-semiconductors-at-the-interface-of-two-immiscible-liquids(5652496a-6e6d-4e91-a21b-6ae1b3f36a87).html.
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Deposition of noble metal and semiconductor nanocrystalline thin films has received much attention. CdS and CdSe are important semiconductors used in optical devices. A wet chemical route which uses the interface of two immiscible liquids to control the growth and deposition of nanocrystalline thin films forms the basis of the current study. In this method, a metal precursor dissolved in toluene or decane is held in contact with a water layer containing a reducing or sulphiding agent. The reaction proceeds at the interface of the liquids and results in deposits adhering to the interfacial region. The products of such reactions typically consist of nanocrystals forming a thin film. Stable sols of Au, Ag were found to metathesize on contact with alkylamine in oil to form monolayer films that spread across large areas at the water/oil interface. The nature and properties of interfacial thin films depend on the alkylamine. Nanocrystalline thin films consisting of CdS adhering to the interface starting with a polydispersed aqueous sol of crystallites and alkylamine were obtained. The optical band gaps of the films formed are dependent on the alkylamine chain length, with the shortest chain yielding the largest gap. A systematic increase in particle diameters following adsorption is responsible for changes in the electronic structure of films. The formation of nanocrystalline films of CdS adhering at the interface using a toluene solution of cadmium diethyldithiocarbamate and aqueous Na2S solution, in the presence of tetraoctylammonium bromide (TOAB) in the aqueous phase, was investigated under various reaction parameters, while CdSe was obtained using Na2SeSO3 solution and the influences of deposition temperature and solution concentration were studied. A ternary water/decane/2-butoxyethanol /salt system was used to grow deposits of CdSe and CdS. Nanostructured thin films were obtained at the upper interface of the ternary system, between the emulsive middle layer and oil rich top phase. The influence of deposition conditions such as precursor concentrations and temperature, as well as the nature of the medium on the properties of the deposits was studied. Deposits grown using the ternary system were compared with those obtained using water/decane and water/toluene systems. Reaction parameters such as temperature, solution concentration and the size of CdS and CdSe were controlled. A thin film of CdS and CdSe nanocrystals was formed at the interface. The grain size was found to be dependent on reaction temperature and solution concentration, with higher temperatures and solution concentration resulting in larger grains. The nature of thin films obtained at the interface of two immiscible liquids and of a water/decane/2-butoxyethanol/salt ternary system were studied using Scanning and Transmission electron microscopy, X-ray diffraction and UV-visible spectroscopy.
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Gauthier-Fournier, François. "Structures d'un système ternaire tensioactif zwitterionique/alcool/eau : cas de la N-dodécyl-bétai͏̈ne." Montpellier 2, 1986. http://www.theses.fr/1986MON20093.
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Elaboration du diagramme de phases du systeme ternaire n-dodecylbetaine/pentanol/eau. Etude des structures des phases micellaires et lamellaires par diffusion de lumiere et des mesures de viscosite et de nombre d'agregation
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Wang, Yana. "Self-incompatible solvents with ionic groups." Doctoral thesis, Universitätsbibliothek Chemnitz, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-107041.
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The concept of a self-incompatible solvent is introduced as a molecule composed of two parts (compound 1 and 2) with unfavourable interactions. A third compound will be readily dissolved in this solvent to diminish this unfavourable interaction by dilution. The more incompatible compounds 1 and 2 are, the stronger this behaviour is expected to be. In this work, ionic liquids comprising non-polar carbon chain and polar ionic group are chosen to serve as a model of self-incompatible solvent. The interactions parameters k of the ionic liquids with active ingredients are investigated to examine the effect of self-incompatibility of the ionic liquid molecule.
On the other hand, phase separation between compounds 1 and 2 will reduce the positive effect of self-incompatibility. The tendency of phase separation is increasing with increasing size of the two compounds. Thus, if compounds 1 and 2 are blocks tied together into a block copolymer, one expects a decreasing ability of the block copolymer to dissolve an active ingredient with increasing block length. In this work the ability of polybutadiene-block-poly(2-vinylpyridine) (PB-b-P2VP) block copolymers to dissolve the model compound anthracene is investigated. As expected, the solubility indeed decreases with increasing block length.
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Peraudeau, Gilles. "Contribution à l'étude de la dissolution de la vapeur d'eau dans les silicates liquides : (Système ternaire SiO₂-Al2O₃-CaO)." Bordeaux 1, 1985. http://www.theses.fr/1985BOR10567.
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LA DISSOLUTION DE LA VAPEUR D'EAU DANS LES LIQUIDES DU SYSTEME TERNAIRE SiO₂-Al2O₃-CaO A ETE MESUREE. LES PARAMETRES PRESSION DE VAPEUR D'EAU ET TEMPERATURE DE SATURATION ONT ETE ETUDIES DANS LES DOMAINES 105 < P(H2O) < 5 108 PA ET 1450 < T < 1850 K. L'EFFET DE LA COMPOSITION A ETE EXAMINE LE LONG DES DROITES CORRESPONDANT A CaO/Al2O₃ = 1 ; SiO₂/CaO = 2 ET SiO₂/Al2O₃ = 1,16. LA CARACTERISATION STRUCTURALE DES LIQUIDES ANHYDRES A ETE EFFECTUEE SUR DES VERRES OBTENUS PAR TREMPE PAR SPECTROMETRIE RAMAN, LEURS PROPRIETES THERMODYNAMIQUES ONT ETE ABORDEES PAR CALORIMETRIE DE DISSOLUTION. L'ETAT DE L'EAU DANS LES ALUMINO SILICATES LIQUIDES A ETE ETUDIE PAR SPECTROMETRIE INFRAROUGE, SPECTROMETRIE RAMAN ET SPECTROMETRIE DES PHOTOELECTRONS X
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Wan, Chuangeng. "Étude de la liaison métal-alumine élaborée par voies liquide et solide : mouillage, thermocompression." Grenoble INPG, 1992. http://www.theses.fr/1992INPG0023.
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La premiere partie de cette etude a ete consacree a la conception de deux nouveaux alliages de brasure de l'alumine en visant des caracteristiques optimales pour l'utilisateur. L'essentiel du travail a consiste en une etude des proprietes de mouillage, realisee par la methode de la goutte posee sous vide pousse, avec les deux alliages cupdti et nifecrsiti sur substrats mono et polycristallins d'alumine. Les interfaces et les produits de reaction ont ete caracterises par rugosimetrie, microscopie electronique a balayage et micro-analyse, et les resultats discutes a l'aide d'arguments thermodynamiques. La deuxieme partie a ete consacree a des aspects fondamentaux de la realisation par thermocompression d'une liaison entre monocristaux d'alumine et de nickel. Le travail a montre que l'on pouvait transposer a un couple metal-ceramique un modele de cinetique de soudage developpe pour des couples metalliques. Un calcul de reseau de coincidence a permis de confirmer que l'une des orientations cristallographiques relatives frequemment mentionnee dans la litterature, etait tres certainement energetiquement favorable. Avec cette orientation relative, nous avons pu effectivement synthetiser une serie d'echantillons bicristallins par thermocompression sous vide secondaire. La caracterisation de l'interface a ete faite par microscopie optique, microscopie electronique a balayage et en transmission.
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Albourine, Abdallah. "Deux acides aminés constituants des graines de soja et de luzerne : la l-arginine et son analogue structural toxique la l-canavanine : identification par chromatographie liquide à haute performance : complexations binaire et ternaire avec Cu (II), Ni (II) et Zn (II)." Lyon 1, 1990. http://www.theses.fr/1990LYO10260.
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Au nombre des sources de proteines vegetales, on peut citer les graines de soja (alimentation humaine) et les graines de luzerne (alimentation animale) dont l'une des caracteristiques est de contenir a l'etat libre la 1-canavanine, analogue structural de la 1-arginine. Ces deux acides amines sont extraits directement sous leur forme non-proteinique. L'identification des produits et leur dosage son assures par chromatographie liquide a haute performance (clhp) et nous pouvons etablir un rapport de concentration 1-canavanine/1-arginine considere comme un critere de toxicite. Dans le but d'etablir une comparaison raisonnee entre ces deux acides amines, nous effectuons un examen des ligands et des complexes binaires et ternaires avec des metaux essentiels a la vie: cu(ii), ni(ii) et zn(ii). Les differentes constantes de stabilite ont ete determinees a 25#oc et a force ionique 0,1(nano#3). Cette technique est completee par des mesures spectrophotometriques, de dichroisme circulaire et de pouvoir rotatoire qui conduisent aux facteurs intensifs molaires correspondants. Pour cu#2#+ et zn#2#+, ces differentes mesures mettent en evidence deux complexes ml et ml#2, la 1-canavanine se comportant comme un ligand tridente et la 1-arginine comme un ligand bidente. Pour ni#2#+, nous sommes en presence de trois complexes nil, nil#2 et nil#3. La 1-canavanine prend un caractere bidente lors de la formation du complexe ni(can)#3. Afin de mieux cerner les groupemens chelatants, une approche theorique quantique des molecules a l'etat isole est engagee
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Merrachi, El Houssine. "Propriétés physico-chimiques de quelques trioxalato-métallates alcalins : étude du système ternaire H²O -(NH4)3[Cr(C2O4)3]-(NH4)3 [Fe(C2O4)3] : cristallochimie des trihydrates MI3[MIII(C2O4)3],3H2O (MI=NH4, Rb et MIII=Cr, Fe)." Lyon 1, 1988. http://www.theses.fr/1988LYO10014.
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Synthese et caracterisation des solutions solides possibles entre (nh::(4))::(3)(cr(c::(2)o::(4))::(3))3h::(2)o et (nh::(4))::(3)(fe(c::(2)o::(4))::(3))3h::(2)o en vue d'obtenir des oxydesmixtes fe-cr. Etude des diagrammes des solutions ternaires et binaires h::(2)o-(nh::(4))::(3)(cr(c::(2)o::(4))::(3))-(nh::(4))::(3)(fe(c::(2)o::(4))::(3)). Structures cristallines de (nh::(4))::(3)(m(c::(2)o::(4))::(3))3h::(2)o avec m=cr, fe et de rb::(3)(cr(c::(2)o::(4))::(3))3h::(2)o. Etude des systemes binaires h::(2)o-(nh::(4))::(3)(cr(c::(2)o::(4))::(3)) et h::(2)o-(nh::(4))::(3)(fe(c::(2)o::(4))::(3)) entre -10 et 150**(o)c. Structures des complexes (nh::(4))::(3)(cr(c::(2)o::(4))::(3))3h::(2)o (triclinique), (nh::(4))::(3)(fe(c::(2)o::(4))::(3))3h::(2)o et rb::(3)(cr(c::(2)o::(4))::(3))3h::(2)o (monocliniques). L'ensemble des resultats permet d'aborder le diagramme ternaire h::(2)o-(nh::(4))::(3)(cr(c::(2)o::(4))::(3))-(nh::(4))::(3)(fe(c::(2)o::(4))::(3))
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Azzaoui, Mouhsine. "Modélisation des liquides métalliques ternaires pour le calcul des diagrammes d'équilibre à partir des mesures thermodynamiques ciblées : systèmes tests : (Pb, Sn, Sb), (Pb, Sn, Bi), (Pb, Sn, Ca)." Nancy 1, 1995. http://www.theses.fr/1995NAN10032.
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Le calcul des diagrammes d'équilibre ternaires nécessite une bonne représentation analytique des grandeurs thermodynamiques d'excès des phases étendues. L’établissement de ces fonctions doit s'appuyer sur un nombre minimum, mais suffisant, d'informations expérimentales. Le formalisme quadratique de Darken, dans le cas des systèmes ternaires, permet de lisser les grandeurs d'excès dans les domaines des solutions moyennement diluées (xi 0,333). En divisant un système ternaire en trois quadrilatères adjacents, le formalisme de Darken nécessite 12 paramètres d'interaction binaires et seulement 3 paramètres d'interaction ternaires pour accéder à trois représentations distinctes, mais complémentaires, chacune valable dans l'un des trois quadrilatères. Un nombre très restreint de mesures ternaires est donc requis. Les fonctions d'excès représentées par le formalisme de Darken présentent des discontinuités sur les isoplèthes de raccordement des 3 quadrilatères. Un développement aux 5eme degré des polynômes de Redlich-Kister permet d'accéder à une représentation continue des fonctions d'excès. La validité de nos deux méthodes d'ajustement a été testée avec succès dans le cas des solutions liquides ternaires (Pb, Sn, Sb), (Pb, Sn, Bi) tt (Pb Sn, Ca). Enfin, pour le calcul des diagrammes d'équilibre, qui reste l'objectif final de ce travail, nous avons tenté avec succès une optimisation des paramètres ajustables décrivant les phases binaires et ternaires du système (Pb, Sn, Sb) en utilisant les deux logiciels Thermo-Calc et Nancyun
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Alibrahim, Moussa. "Systèmes à base de tensio-actifs non ioniques : Influence de co-tensio-actifs ioniques et structure des phases mésomorphes." Nancy 1, 1988. http://www.theses.fr/1988NAN10061.
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Détermination des diagrammes de phase de systèmes à base de poly(oxyethylène) ether dodécyle et de faibre quantité de décane, à l'aide de la méthode isotherme et par balayage automatique en température. Étude structurale des zones cristallines par diffraction des rayons X
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Jonquières, Anne. "Influence de la structure des matériaux et perméants sur les propriétés de sorption et de transfert dans des systèmes polymère / liquides organiques : application à la séparation par pervoration de mélanges alcool-éther à l'aide de polyuréthaneimides (PUI) et modélisation du transfert dans le cas d'un système ternaire." Vandoeuvre-les-Nancy, INPL, 1994. http://www.theses.fr/1994INPL095N.
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Ce mémoire résume les résultats d'une étude systématique concernant les propriétés d'une importante série de polyuréthaneimides (PUI) copolymères à blocs à structure évolutive lors de la pervaporation de mélanges exclusivement organiques avec un intérêt particulier pour la séparation du mélange azéotropique EtOH/ETBE. Environ 40 polyuréthaneimides ont été synthétisés par une méthode permettant le contrôle de la structure du matériau. Les résultats obtenus en pervaporation ont montré une nette tendance de relations propriétés-structure très utile pour la recherche d'une membrane d'intérêt industriel. Restreinte à des PUI ne différant que par leur segment flexible, cette étude permet d'établir une corrélation quantitative entre la sélectivité en pervaporation et un paramètre de sélectivité d'interaction, défini à partir du paramètre de solubilité du segment flexible calculé à partir de méthodes par contribution de groupes. Une approche nouvelle permet ensuite de corréler les propriétés en pervaporation et en sorption à l'aide de paramètres de polarité. Les corrélations quantitatives sont établies pour de nombreux systèmes ternaires différant par les matériaux ou les perméants impliqués. L'étude de nombreuses données publiées sur la sorption d'un liquide pur dans un polymère montre par ailleurs la généralité de ce type de corrélation qui s'applique à des systèmes très variés. La dernière partie concerne la modélisation du transfert dans le cas d'un véritable système ternaire selon une loi de FICK thermodynamique qui considère la forte non-idéalité du système. Les lois décrivant l'équilibre thermodynamique de sorption sont particulièrement simples et mettent en évidence la saturation préliminaire des groupes uréthane par l'éthanol. La comparaison des différents paramètres calculés (modèle ou perméation différentielle) conduit à remettre en question la validité de la loi de FICK adoptée pour décrire le transfert en pervaporation
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Bayuadri, Cosmas. "Stability of sodium sulfate dicarbonate (~2Na₂CO₃• Na₂SO₄) crystals." Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11507.
Full textAbstract:
Research on salts species formed by evaporation of aqueous solution of Na2 in the early 1930s. The thermodynamic, crystallographic and many other physical and chemical properties of most of the species formed from this solution has been known for decades. However, there was no complete information or reliable data to confirm the existence of a unique double salt that is rich in sodium carbonate, up until five years ago when a research identified the double salt (~2Na ₂ CO ₃ • Na ₂ SO ₄) from the ternary system Na₂CO ₃Na₂SO ₄ H₂O. Crystallization of this double salt so called sodium sulfate dicarbonate (~2Na ₂ CO ₃ • Na ₂ SO ₄) is known to be a primary contributor to fouling heat transfer equipment in spent-liquor concentrators used in the pulp and paper industry. Therefore, understanding the conditions leading to formation of this double salt is crucial to the elimination or reduction of an industrial scaling problem. In this work, double salts were generated in a batch crystallizer at close to industrial process conditions. X-ray diffraction, calorimetry, and microscopic observation were used to investigate the stability of the salts to in-process aging, isolation and storage, and exposure to high temperature. The results show that care must be taken during sampling on evaporative crystallization. Two apparent crystal habits were detected in the formation of sodium sulfate dicarbonate; the favored habit may be determined by calcium ion impurities in the system. The results also verify that sodium sulfate dicarbonate exists as a unique phase in this system and that remains stable at process conditions of 115-200℃
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De, Muer Albin. "Etude du point critique magnétique quantique des fermions lourds sous pression hydrostatiques." Université Joseph Fourier (Grenoble), 2000. http://www.theses.fr/2000GRE10104.
Full textAbstract:
Ce travail repose sur le developpement de mesures physiques sous la pression la plus hydrostatique possible, condition essentielle pour etudier les phenomenes critiques quantiques survenant notamment au voisinage de l'instabilite magnetique des systemes a fermions lourds. Les techniques de resistivite electrique et de calorimetrie alternative ont ete adaptees a des cellules a enclumes diamant utilisant l'excellent milieu transmetteur de pression helium. Un recent dispositif de generation de force a basse temperature permet une variation controlee de la pression in-situ. Trois composes, ceal 2, ceru 2ge 2 et cepd 2si 2, sont etudies. Pour ceal 2, des mesures de resistivite sous pression suggerent une pression critique p c a laquelle la temperature de neel chute a zero, voisine de 30 kbar. Au voisinage de p c, des deviations par rapport au comportement du liquide de fermi sont observees et ce, en accord qualitatif avec les predictions des modeles de fluctuations de spin. L'etude de ceru 2ge 2 a permis de tester l'aptitude de la calorimetrie alternative a detecter des transitions magnetiques. Nous discutons l'apparition de phenomenes irreversibles dans la transition antiferromagnetique a l'approche de la pression critique p c 80 kbar. Cepd 2si 2 est etudie par les deux techniques jusqu'a 33 kbar. Une phase supraconductrice est mise en evidence de part et d'autre de p c 28 kbar. L'evolution des largeurs de transition magnetique et supraconductrice est discutee en comparant les longueurs de coherence correspondantes a une distance caracteristique relative aux defauts de l'echantillon. La dependance en temperature de la resistivite est egalement en accord avec une description en termes de fluctuations de spin. Aux basses temperatures, un exposant de loi de puissance inferieur a 2 est obtenu pour les pressions proches de p c tandis que le comportement en t 2 du liquide de fermi reapparait aux pressions superieures.
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Huang, Chou Cheng, and 周正晃. "Liquid Liquid Equilibrium of Ternary System." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/43433199334269233648.
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LIN, BO-JIUN, and 林伯俊. "Liquid-Liquid Equilibrium Measurements of Ternary Systems of The Type." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/79071616397473106393.
Full textAbstract:
碩士<br>國立臺灣大學<br>化學工程學研究所<br>89<br>ABSTRACT
In this study; The liquid-liquid equilibrium measurements of two ternary system: water/ dodecane/ C4E1 and water/ tertradecane/ C4E1 at 25~45℃ were performed. Then doing the experimental data were numberically regressed with UNIQUAC MODEL. The nonionic surfactant CiEj is the abbreviation of CH3 (CH2)i-1 (OCH2CH2 )jOH, where "i" means the number of nonpolar hydrocarbon chains of hydrophobic groups and "j" is the number of hydrophilic groups.
Gas chromatography method was applied to determine the composition of these liquid-liquid equilibrium systems, and the calibration error is within 0.5. The UNUQUAC interaction parameters were numerically regressed by minimizing the error ofcomposition. For the system with three- liquid- phase- coexisting, all the six interaction parameters can be solved directly from the compositions of three-liquid phase. The detail of regression procedure is discussed.
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Hu, Ho-Hsun, and 胡賀勛. "Liquid-liquid equilibrium measurements of ternary systems of the type water+oil+surfactant." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/00405175103915944234.
Full textAbstract:
碩士<br>國立臺灣大學<br>化學工程學系<br>86<br>Surfactants play an important role in chemical
engineering industry. Besides the use of
emulsification and detergent, they are espe
cially effectively used in the tertiary oil recovery.
The liquid-liquid extraction technology requires
the liquid-liquid equilibrium composition data of
the ternary system of water-oil-surfactant. This
study offers experimental data of equilibrium for
two ternary systems.
We measure the two ternary system:H2O~n-
dodecane~diethylene glycol monohexyl ether
(C6E2) and H2O~n-tetradecane~C6E2 at two dif
ferent temperatures 20℃ and 30℃. In addition
to the traditional gas chromatography, we use
the Karl-Fisher moisture titrator to determine
the water content as well. One three-phase re
gion and three two-phase regions are found for
these two systems. With rising the temperature,
the surfactant-rich phase composition gets
closer to the oil-rich phase composition. That
means the surfactant moves from the water-rich
phase toward the oil-rich phase as the tempera
ture is increased. We also find that the tempera
ture has stronger effect on the system containing
n-dodecane than on the system containing n-
tetradecane.
At last we correlate the experimental results by
the UNIQUAC model. Although the correlated results
are not good enough, the existence of the three phase
region are successfully calculated. Due to the diffi
culty of numerical analysis, it is believed that the
calculated result we get only coincides with the local
minimum, not the global minimum in this highly
nonlinear regression calculations. Therefore, the bet
ter interaction parameters should be resolved by
designing a more efficient regression technique.