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Characterization and applications of pH-responsive polyelectrolyte complex and multilayersSui, Zhijie. Schlenoff, Joseph B. January 2005 (has links)
Thesis (Ph. D.)--Florida State University, 2005. / Advisor: Joseph B. Schlenoff, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed Feb. 1, 2006). Document formatted into pages; contains xvii, 167 pages. Includes bibliographical references.
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Comparative in vitro analysis of a balanced electrolyte solution versus an unbalanced electrolyte solution, for processing of residual pump blood using cell saver for patients undergoing elective cardiac surgeryPillay, Krishnan January 2016 (has links)
Submitted in fulfillment for the degree of Master of Technology, Clinical Technology: Cardiovascular Perfusion, Durban University of Technology, Durban, South Africa, 2016. / Introduction:
A large volume of residual haemodilute blood remains in the cardiopulmonary bypass (CPB) circuit after termination of the bypass. It is common practice in many centres to process residual pump blood with an autologus cell salvage system (ACSS), thereby producing a re-suspended red blood cell (RBC) concentrate and attenuating the need for donor blood RBC concentrate. It has also become standard practice to wash donor pack red blood cells (PRBC) before adding it to neonate cardiopulmonary circuits (Swindell et al., 2007). Manufactures of ACSS recommend 0.9% sodium chloride (NaCl) as a wash solution for processing salvaged blood. Previous studies have demonstrated that washing PRBC with normal saline results in acid-base (Huber et al., 2013) and electrolyte derangements (Varghese et al., 2007). Infusion of normal saline in healthy volunteers also results in significant changes in osmolality (Williams et al., 1999). The use of normal saline as a wash solution in processing residual CPB blood requires investigation.
Aims and Objectives:
This was a prospective, quantitative in vitro investigation to analyze and compare the quality of residual pump blood post CPB that had been washed with either an unbalanced electrolyte solution (0.9% normal saline) or a balanced electrolyte solution (Balsol®). Both are crystalloid solutions. The primary objective of the present study was to measure and compare the pH, electrolytes, metabolites, osmolality and strong ion difference (SID) of residual pump blood to the pH, electrolytes, metabolites, osmolality and SID of processed cell saver blood, which was washed with either 0.9% normal saline or Balsol® solution. The secondary objective was to measure and compare protein levels (albumin and total protein) in residual pump blood to protein levels in processed cell saver blood, that is washed with either 0.9% normal saline or Balsol® solution. The final objective was to determine the volume, haematocrit and haemoglobin yield post cell saver processing, from the input volume of residual pump blood when washed with either 0.9% normal saline or Balsol® solution. This was the first study of this nature done in the South African population group.
Methodology:
In this investigation in a series of forty patients (n=40) undergoing elective cardiac surgery with CPB, the first twenty patients were allocated to the NaCl control group (n=20) and the second twenty patients were allocated to the Balsol® interventional group (n=20). The extracorporeal circuit consisted of a standard integral hollow fibre membrane oxygenator and tubing that was primed with 1500-1800 millilitres of balanced crystalloid solution (Balsol®), for both the control group and the interventional group, and addition of 5000 iu heparin. The balanced crystalloid solution (Balsol®) is the approved standard CPB priming solution for all cardiac procedures at Inkosi Albert Luthuli Central Hospital.
This setup was used with the Stockert S5 roller pump heart lung machine. The operations were performed as per protocol with standard non-pulsatile CPB and hypothermia was maintained at 28 – 32 ºC (core) and haemodilution (haematocrit 20 % to 30 %). A standard flow rate of 2.4 L/min/m² was used. Cardio protection consisted of either cold Blood Cardioplegia using the Buckberg 4:1 ratio, being four parts blood to one part cardioplegia (with the 35ml of 20 % Dextrose + 1 gram Magnesium Sulphate added per 500ml), or 20ml/kg cold St Thomas II cardioplegia (with addition of 10ml of 8.5% NaHCO3 + 100mg lignocain per litre). Topical cooling was achieved with ice cold 0.9 % saline. Maintenance fluid used during CPB was Balsol® for both the control and the interventional groups. Calcium, potassium and sodium bicarbonate was administered as required during CPB to correct deficits for both groups. Weaning of CPB was performed after re-warming to a rectal temperature of at least 35 ºC for both study groups.
Immediately on termination of CPB a blood sample was taken from the sampling manifold of the CPB circuit for pre wash analysis. Residual pump blood was then flushed out with one litre of Balsol® solution for both groups and collected into the Medtronic autolog cell saver reservoir to be processed. In the control study group 0.9% NaCl was used as the wash solution and in the interventional study group Balsol® solution was used as the wash solution. After processing of the salvaged blood is complete, a blood sample was taken for post wash analysis. Clinical data recorded for pre and post wash samples included: pH, pCO2, pO2, [K+], [Na+], [Cl-], [Ca2+], lactate, glucose, [HCO3-], TCO2, haematocrit, haemoglobin (GEM 4000® premier™ blood gas analyser) blood volume (Medtronic autolog) and SID (calculated as per equation). Inorganic phosphate, total magnesium, albumin, total protein (Siemens Advia 1800 blood gas analyser) and osmolality (Gonotech osmometer) were also measured.
Results:
There was a highly significant decrease (p < 0.05) within the NaCl group after washing with pCO2 (28.3 ± 2.9 vs. <6.0 ± 0.0), [K+] (4.5 ± 0.5 vs. 1.0 ± 0.7), total magnesium (1.7 ± 0.7 vs. 0.29 ± 0), ionized calcium (1.0 ± 0.09 vs. 0.1 ± 0.03), inorganic phosphate (0.9 ± 0.4 vs. 0.09 ± 0.04) and SID (27.1 ± 2.1 vs. 18.4 ± 2.2). There was a highly significant increase (p < 0.05) within the NaCl group after washing with pH (7.5 ± 0.1 vs. 7.7 ± 0.1), [Na+] (132.9 ± 3.2 vs. 146.3 ± 1.9), [Cl-] (107.8 ± 3.1 vs. 127.4 ± 2.1) and osmolaltity (256.9 ± 38.4 vs. 296.2 ± 57.5).
There were highly significant decrease (p < 0.05) within the Balsol® group after washing with pCO2 (30.15 ± 6.0 vs. 18.9 ± 4.9), [Na+] (134.7 ± 2.2 vs. 125.6 ± 1), [Cl-] (108.8 ± 2.7 vs. 100.2 ± 1.4), ionized calcium (0.9 ± 0.1 vs. 0.02 ± 0.04), inorganic phosphate (0.8 ± 0.2 vs. 0.1 ± 0.024) and osmolality (288.8 ± 20.6 vs. 272.8 ± 19.9). There were highly significant increase (p < 0.05) within the Balsol® group after washing with pH (7.5 ± 0.1 vs. 7.7 ± 0.1), [K+] (4.2 ± 0.4 vs 4.6 ± 0.3). Total magnesium and SID were similar after washing within the Balsol® group. Albumin and total protein revealed similar significant decreases within both groups after washing.
There was a highly significant difference (p < 0.05) in the change between groups after washing in all the variables measured, except for pH, inorganic phosphate, lactate, glucose, albumin, total protein, haematocrit, haemoglobin, and blood volume. Total carbon dioxide and [HCO3-] were not compared because they were incalculable by blood gas analyser in the NaCl group.
Conclusion:
This investigation concluded that the balanced electrolyte solution Balsol® used for washing residual CPB blood results in a re-suspended RBC concentrate, with an osmolality and electrolyte profile that is superior compared to washing residual CPB blood with 0.9% NaCl solution. / M
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Simulating Osmotic Equilibria by Molecular Dynamics - From Vapor-Liquid Interfaces to Thermodynamic Properties in Concentrated Solutions / Simulation des Équilibres Osmotiques par la Dynamique Moléculaire - Des Interfaces Vapeur-Liquide aux Propriétés Thermodynamiques dans les Solutions Concentrées.Bley, Michael 21 November 2018 (has links)
L’objectif de cette thèse de doctorat est le développement d’une nouvelle méthode théorique basée sur la simulation des équilibres liquide-gaz par simulations de dynamique moléculaire. Cette nouvelle m´méthode prédit les propriétés thermodynamiques telles que l’activité des solvants et les coefficients d’activité des solutés en phases aqueuses et organiques impliquées dans les systèmes d’extraction liquide-liquide. Ces propriétés thermodynamiques sont nécessaires pour les approches de modélisation thermodynamique mésoscopique permettant d’estimer l’efficacité et la s´électivité d’un système d’extraction par solvant jusqu’au une échelle industrielle. Les propriétés thermodynamiques et structurales des solutions électrolytiques aqueuses et des phases organiques, y compris les agrégats résultant des molécules d’extraction des amphiphiles, sont en bon accord avec les données expérimentales et théoriques disponibles. L’approche de dynamique moléculaire de l’équilibre osmotique fournit un nouvel outil puissant permettant d’accéder aux données thermodynamiques. / The aim of this PhD thesis is the development of a new theoretical method based on the simulation of vapor-liquid equilibria by means of molecular dynamics (MD) simulation. This new method predicts thermodynamic properties such as solvent activities and solute activity coefficients of aqueous and organic phases used in liquid-liquid extraction systems. These thermodynamic properties are required for mesoscopic thermodynamic modeling approaches estimating the efficiency and selectivity of a given solvent extraction system up to an industrial scale. Thermodynamic and structural properties of aqueous electrolyte solutions and organic solvent phase including aggregates resulting from amphiphilic extractant molecules are reproduced in very good agreement with previously available experimental and theoretical data. The osmotic equilibrium MD approach provides a new and powerful tool for accessing thermodynamic data
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Manejo da fertirrigação em ambiente protegido visando o controle da salinidade do solo para a cultura da berinjela / Fertigation management in a greenhouse for the soil salinity control in eggplant cropSilva, Everaldo Moreira da 28 January 2011 (has links)
Com o monitoramento periódico da solução do solo, pode-se determinar a condutividade elétrica e a concentração de íons específicos, essenciais à nutrição das plantas. Dentre as técnicas de extração da solução do solo, o extrator de cápsula porosa destaca-se pela praticidade em campo, baixo custo, fácil manejo e boa precisão. Com isso objetivou-se estudar os efeitos de diferentes níveis de salinidade do solo sobre as variáveis fenológicas e de produção da berinjela, cultivada em vasos e em ambiente protegido, e averiguar se a manutenção da condutividade elétrica em um determinado nível promove incremento da produção, quando contrastada com o manejo tradicional da fertirrigação. Conduziu-se um estudo em ambiente protegido na área experimental do Departamento de Engenharia de Biossistemas da ESALQ/USP, Piracicaba, SP. Os tratamentos foram compostos da combinação de dois fatores: 6 níveis de salinidade inicial do solo (S1 = 1,3; S2 = 2,4; S3 = 3,6; S4 = 4,5; S5 = 5,6 e S6 = 6,4 dS m-1) e dois manejos de fertirrigação: com controle da condutividade elétrica da solução do solo (M1), e o tradicional (M2), obedecendo a curva de absorção de nutrientes da cultura anteriormente estabelecida. O delineamento estatístico adotado foi o de blocos casualizados completos, com quatro repetições, ficando os fatores estudados arranjados no esquema fatorial 6 x 2. Os diferentes níveis de salinidade inicial do solo foram obtidos com solos de cultivos anteriores, no qual tinha-se como fonte de variação o nível de condutividade elétrica (CE), ocasionada pela adição de fertilizantes em ambiente protegido. A condutividade elétrica da solução foi medida após o término de cada evento de irrigação, utilizando-se extratores com cápsulas porosas. Os resultados revelaram que os níveis de salinidade do solo provenientes do acúmulo de sais fertilizantes afetou diretamente as variáveis consumo hídrico, produção de frutos, produção de matéria seca, índice de área foliar e o desenvolvimento vegetativo das plantas. O uso dos extratores de solução permitiu auxiliar o manejo da fertirrigação, mantendo os níveis desejados de salinidade da solução do solo ao longo do tempo. Verificou-se que a redução média na produção da cultura da berinjela, em estufa, foi da ordem de 8,65% para o incremento de 1 dS m-1 na salinidade do solo, acima da salinidade limiar, que foi de 1,71 dS m-1. / Periodic monitoring of soil solution allow to determine the electrical conductivity and concentration of specific ions essential to plant nutrition. Among the extraction techniques of soil solution, the porous cup extractors distinguished by their practicality in the field, low cost and good accuracy. This study has to aim to evaluate the effects of different levels of soil salinity on phenological and production of eggplant grown in pots in a greenhouse, and compare whether the control of the electrical conductivity in a certain level promotes increase the yield when compare to the traditional fertigation management . A study was conducted in a greenhouse in the Department of Biosystems Engineering, ESALQ / USP, Piracicaba, SP, Brazil. The treatments consisted of a combination of two factors: six levels of initial soil salinity (S1 = 1.3, S2 = 2.4, S3 = 3.6, S4 = 4.5, S5 = 5.6 and S6 = 6.4 dS m-1) and two fertigation management: electrical conductivity control of soil solution (M1) and traditional (M2) by following the absorption curve of nutrients from the crop previously established. The statistical design was a randomized complete block with four repetitions, the factors studied arranged in 6 x 2 factorial. The different levels of initial soil salinity were obtained with soils where previous crop had been cropped in a source of variation in the level of electrical conductivity (EC), caused by the addition of fertilizer in a pots. The solution electrical conductivity was measured after each irrigation event, using extractants with ceramic cups. The results showed that levels of soil salinity caused by the accumulation of fertilizer salts affected directly the variables: water use, fruit yield, dry matter production, leaf area index and plant growth. The use of extractors solution allowed to control the fertigation management, and maintain the desired levels of salinity in the soil solution during the evaluated period. It appears that the reduction in eggplant yield in greenhouse was approximately 8.65% for step of 1 dS m-1 in soil salinity, the threshold salinity was 1.71 dS m-1.
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Manejo da fertirrigação em ambiente protegido visando o controle da salinidade do solo para a cultura da berinjela / Fertigation management in a greenhouse for the soil salinity control in eggplant cropEveraldo Moreira da Silva 28 January 2011 (has links)
Com o monitoramento periódico da solução do solo, pode-se determinar a condutividade elétrica e a concentração de íons específicos, essenciais à nutrição das plantas. Dentre as técnicas de extração da solução do solo, o extrator de cápsula porosa destaca-se pela praticidade em campo, baixo custo, fácil manejo e boa precisão. Com isso objetivou-se estudar os efeitos de diferentes níveis de salinidade do solo sobre as variáveis fenológicas e de produção da berinjela, cultivada em vasos e em ambiente protegido, e averiguar se a manutenção da condutividade elétrica em um determinado nível promove incremento da produção, quando contrastada com o manejo tradicional da fertirrigação. Conduziu-se um estudo em ambiente protegido na área experimental do Departamento de Engenharia de Biossistemas da ESALQ/USP, Piracicaba, SP. Os tratamentos foram compostos da combinação de dois fatores: 6 níveis de salinidade inicial do solo (S1 = 1,3; S2 = 2,4; S3 = 3,6; S4 = 4,5; S5 = 5,6 e S6 = 6,4 dS m-1) e dois manejos de fertirrigação: com controle da condutividade elétrica da solução do solo (M1), e o tradicional (M2), obedecendo a curva de absorção de nutrientes da cultura anteriormente estabelecida. O delineamento estatístico adotado foi o de blocos casualizados completos, com quatro repetições, ficando os fatores estudados arranjados no esquema fatorial 6 x 2. Os diferentes níveis de salinidade inicial do solo foram obtidos com solos de cultivos anteriores, no qual tinha-se como fonte de variação o nível de condutividade elétrica (CE), ocasionada pela adição de fertilizantes em ambiente protegido. A condutividade elétrica da solução foi medida após o término de cada evento de irrigação, utilizando-se extratores com cápsulas porosas. Os resultados revelaram que os níveis de salinidade do solo provenientes do acúmulo de sais fertilizantes afetou diretamente as variáveis consumo hídrico, produção de frutos, produção de matéria seca, índice de área foliar e o desenvolvimento vegetativo das plantas. O uso dos extratores de solução permitiu auxiliar o manejo da fertirrigação, mantendo os níveis desejados de salinidade da solução do solo ao longo do tempo. Verificou-se que a redução média na produção da cultura da berinjela, em estufa, foi da ordem de 8,65% para o incremento de 1 dS m-1 na salinidade do solo, acima da salinidade limiar, que foi de 1,71 dS m-1. / Periodic monitoring of soil solution allow to determine the electrical conductivity and concentration of specific ions essential to plant nutrition. Among the extraction techniques of soil solution, the porous cup extractors distinguished by their practicality in the field, low cost and good accuracy. This study has to aim to evaluate the effects of different levels of soil salinity on phenological and production of eggplant grown in pots in a greenhouse, and compare whether the control of the electrical conductivity in a certain level promotes increase the yield when compare to the traditional fertigation management . A study was conducted in a greenhouse in the Department of Biosystems Engineering, ESALQ / USP, Piracicaba, SP, Brazil. The treatments consisted of a combination of two factors: six levels of initial soil salinity (S1 = 1.3, S2 = 2.4, S3 = 3.6, S4 = 4.5, S5 = 5.6 and S6 = 6.4 dS m-1) and two fertigation management: electrical conductivity control of soil solution (M1) and traditional (M2) by following the absorption curve of nutrients from the crop previously established. The statistical design was a randomized complete block with four repetitions, the factors studied arranged in 6 x 2 factorial. The different levels of initial soil salinity were obtained with soils where previous crop had been cropped in a source of variation in the level of electrical conductivity (EC), caused by the addition of fertilizer in a pots. The solution electrical conductivity was measured after each irrigation event, using extractants with ceramic cups. The results showed that levels of soil salinity caused by the accumulation of fertilizer salts affected directly the variables: water use, fruit yield, dry matter production, leaf area index and plant growth. The use of extractors solution allowed to control the fertigation management, and maintain the desired levels of salinity in the soil solution during the evaluated period. It appears that the reduction in eggplant yield in greenhouse was approximately 8.65% for step of 1 dS m-1 in soil salinity, the threshold salinity was 1.71 dS m-1.
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Aplicação do método da minimização da energia de Gibbs no cálculo de equilíbrio químico e de fases em sistemas eletrolíticos / Application method of the Gibbs energy minimization to calculation of phase and chemical equilibrium in electrolyte systemsTrindade Júnior, Valter Nunes 19 August 2018 (has links)
Orientadores: Reginaldo Guirardello, Edson Antonio da Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-19T12:35:11Z (GMT). No. of bitstreams: 1
TrindadeJunior_ValterNunes_M.pdf: 1919393 bytes, checksum: 3d6999675b8995d4420ac44773a78c43 (MD5)
Previous issue date: 2011 / Resumo: Em diversas aplicações industriais são utilizadas misturas contendo diferentes solutos, muitas vezes estes são solutos não voláteis, como por exemplo, os eletrólitos. O equilíbrio químico e de fases ocorrem nas diversas operações unitárias contidas nessas aplicações. As próprias etapas de produção, bem como as etapas de separação e purificação, são fundamentais para a qualidade dos produtos. Com isso, o cálculo do comportamento do equilíbrio de sais em solventes é de grande importância para o projeto e a otimização desses equipamentos. Desta forma, o objetivo principal deste trabalho foi o desenvolvimento de uma metodologia confiável e robusta para o cálculo do equilíbrio químico e de fases combinado, em soluções eletrolíticas. O estudo do comportamento do equilíbrio foi feito com a variação da pressão e/ou a temperatura nos sistemas estudados. Este trabalho propôs uma modelagem considerando uma fase vapor, n fases liquidas e uma fase sólida, por meio da metodologia de minimização da energia de Gibbs. A fase vapor foi considerada ideal e a fase solida foi considerada como sólido puro. Para representação da não idealidade da fase líquida foi utilizado o modelo NRTL eletrolítico, esta formulação matemática resulta em um problema que deve ser tratado como um problema de otimização não-linear. Os resultados obtidos foram comparados com dados experimentais extraídos da literatura em sistemas contendo um sal em solução com um solvente ou misturas de solventes no equilíbrio sólido-líquido e no equilíbrio líquido-vapor. A vantagem desta abordagem é não ter que estabelecer previamente quais fases se formarão, o processo de minimização da energia de Gibbs estabelece o número de fases formadas nos sistema automaticamente. Para a resolução do problema de otimização foi utilizado o software GAMS® (General Algebraic Modeling Systems), versão 23.2.1, com o solver CONOPT que utiliza o algoritmo do Gradiente Generalizado Reduzido / Abstract: In several industrial applications are used mixtures containing different solutes, often these solutes are non-volatile, such as electrolytes. The phase and chemical equilibrium in these processes occur in the various unit operations. The stages of production, as well as the separation and purification steps are critical to product quality. Thus, the calculation of the behavior of the equilibrium of salts in solvents is of great importance for the design and optimization of this type of equipment. The main objective of this work was to develop a methodology for calculation of the combined phase and chemical equilibrium in electrolytic solutions. In this study, the behavior of the equilibrium was done by varying the pressure and the temperature in the systems studied. In the model were made the following considerations: a vapor phase, n liquid phase and a solid phase, using the methodology of minimizing the Gibbs energy. The vapor phase was considered ideal and phase solida was considered as pure solid. To represent the nonideality of the liquid phase we used the electrolyte NRTL model (e-NRTL), in this way, the problem should be treated as a nonlinear optimization problem. The results were compared with literature data with solutions containing an electrolyte in solvent or solvents mixtures for Solid-Liquid and vapor-Liquid equilibrium. The modeling was written as a nonlinear programming. The advantage of this program is not having to know in advance what phases will be formed, the process of minimization of Gibbs energy determines the phases automatically. The program was solved in GAMS® software (General Algebraic Modeling System), version 23.2.1, with CONOPT solver that uses the Generalized Reduced Gradient algorithm / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química
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Description analytique des phénomènes acoustophorétiques, en solutions et suspensions / Analytical description of acoustophoretic phenomena, in solutions and in suspensionsGourdin, Simon 21 September 2015 (has links)
Cette thèse de doctorat porte sur la description analytique des phénomènes acoustophorétiques, en solutions et suspensions. L'acoustophorèse est la création d'un champ électrique par une onde acoustique.La première partie porte sur les solutions d'électrolytes, et est basée sur l'analyse critique de la littérature. A partir des différents articles, un modèle original, basé sur la résolution des équations de la dynamique pour les ions est trouvé, lequel permet la prédiction, sans paramètres ajustables, de l'acoustophorèse des sels simples pour des solutions allant de très diluées à assez concentrées. Ce modèle est ensuite étendu aux cas de solutions avec trois espèces ioniques différentes, et un programme informatique calculant l'acoustophorèse en fonction de la concentration est en annexe. Une seconde extension est faite pour les liquides ioniques, et permet de déduire le volume des ions. Des tentatives d'extension du modèle sont faites pour les micelles et les colloïdes, en précisant les écueils. Une deuxième approche, basée sur la thermodynamique irréversible et les relations de réciprocité d'Onsager, est faite dans le cas des suspensions colloïdales. Les principaux résultats sont la proportionnalité entre l'acoustophorèse et la mobilité électrique des colloïdes, et donc l'applicabilité de cette technique à la caractérisation des suspensions, y compris concentrées ; le lien rigoureux entre l'acoustophorèse et son corollaire, la création d'une onde acoustique et son champ électrique ; enfin une procédure pour séparer le signal des colloïdes du signal de l'électrolyte support dans l'acoustophorèse des suspensions réelles. / This Ph.D. thesis is on the analytical description of acoustophoretic phenomena, in solutions and suspensions. Acoustophoresis is the creation of an electric field by an acoustic wave.First part is on electrolytic solutions, and it begins by a critical review of literature, from Debye first paper to a recent Ph.D. thesis on the same subject. Hypotheses are carefully selected, and a new model is deduced. This model, using pressure, friction, electric, inertia and corrective force, allows the prediction of acoustophoresis up to 0,3 molar for a simple salt, without any fitting parameter. An extension to solutions with three ionic species is done, and a Fortran program to compute the acoustophoresis as a function of the concentration is given in annex. Extension of the model, in the case of ionic liquid, allows the measurement of the volume of ions. A brief point is done on micellar and colloidal suspensions. A second part is on the application of non-equilibrium thermodynamic, especially Onsager reciprocal relation, to the acoustophoresis of suspensions. Acoustophoresis is shown to be proportional to the electric mobility, which allows the measurement of the latter in dark and concentrated suspensions. A link between acoustophoresis and the creation of acoustic wave by an electric field is also found, and a process to isolate contributions of colloids in real suspensions, with a supporting electrolyte, is proposed.
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NMR-Untersuchungen zur kollektiven Diffusion von Wasser und gelösten Ionen: Die dynamische Hydratationszahl und der Einfluss poröser MaterialienBeckert, Steffen 25 June 2013 (has links)
Gegenstand der Arbeit ist die Untersuchung der kollektiven Diffusion von Wasser und Ionen in wässrigen Elektrolytlösungen. Dabei wird insbesondere die Dynamik der Wassermoleküle innerhalb der Hydratationshüllen der Ionen und der Einfluss poröser Materialien
untersucht. Nach einer Einführung zur Dynamik der Hydratationshülle folgen Grundlagen der NMR-Diffusometrie, welche genutzt wurde um die Selbstdiffusionskoefifizienten der Wassermoleküle und der Ionen der Lösungen zu messen. Daraus wurden die dynamischen Hydratationszahlen der Ionen bestimmt, welche die Anzahl an Wassermolekülen angeben, die durch die Diffusion des Ions in ihrer translatorischen Bewegung beeinflusst sind. Der Einfluss poröser Materialien auf die Dynamik wird am Beispiel nanoporöser Glasmonolithe und mikroporöser Li-LSX Kristalle untersucht.
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Synthesis of lithium manganese phosphate by controlled sol-gel method and design of all solid state lithium ion batteriesPenumaka, Rani Vijaya January 2015 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Due to the drastic increase in the cost of fossil fuels and other environmental issues, the demand for energy and its storage has risen globally. Rather than being dependent on intermittent energy sources like wind and solar energy, focus has been on alternative energy sources. To eliminate the need for fossil fuels, advances are being made to provide energy for hybrid electric vehicles (HEV), plug-in hybrid vehicles (PHEV) and pure electric vehicles (EV) thus providing scope for much greener environment. Hence, focus has been on development in lithium ion batteries to provide with materials that have high energy density and voltage.
Ortho olivine lithium transitional metals are known to be abundant and inexpensive; these compounds are less noxious than other cathode materials. Advancement in research is being done in finding iron and manganese compounds as cathode materials for advanced technologies. However, Lithium manganese phosphates are known to suffer with poor electrochemical performances due the manganese dissolution in the organic liquid electrolyte due to Jahn-Teller Lattice distortion. This problem was tried to endorse in this thesis. In the second chapter by synthesizing nano sized cathode particles with good electronic conductivity, good performance was achieved.
In the third chapter additive olivine cathode was synthesized my modified sol gel process. A wt. % of TMSP was added as an additive in the organic liquid electrolyte. By comparing the properties between the two kinds of electrolytes it was observed that by the addition of the additive in the organic electrolyte good electrochemical properties could be achieved hindering the Mn dissolution in the electrolyte.
In the final chapter, a composite solid electrolyte was fabricated by using NASICON-type glass ceramic of Lithium aluminum titanium phosphate (LATP) with organic binder of Polyethylene oxide. The flexible solid electrolyte exhibited good ionic conductivity. An all solid state cell was fabricated using the composite solid electrolyte using LiMn2O4 as the symmetric electrodes. At different pressures, the performance of the solid state cell was studied.
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