Dissertations / Theses on the topic 'Thermodynamics studies'
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Kjellqvist, Lina. "Studies of Steel/Slag Equilibria using Computational Thermodynamics." Licentiate thesis, Stockholm Stockholm : Materialvetenskap, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3914.
Full textWillson, Richard James. "Isothermal microcalorimetry : theoretical development and experimental studies." Thesis, University of Kent, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283265.
Full textZanchetta, Marcantony. "Kinetic heating and transition studies at hypersonic speeds." Thesis, Imperial College London, 1996. http://hdl.handle.net/10044/1/37124.
Full textBurgess, Sarah Elisabeth. "Membrane transport studies : novel methods, model systems and thermodynamics." Thesis, University of Greenwich, 2005. http://gala.gre.ac.uk/6121/.
Full textFletcher, P. "Studies on the thermodynamics of association of drug molecules." Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375062.
Full textTindall, A. T. R. "Experimental and theoretical studies of convective heat transfer from fin arrays." Thesis, University of Lincoln, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354881.
Full textAllan, William D. E. "Heat transfer and instrumentation studies on rotating turbine blades in a transient facility." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257952.
Full textOlsen, Katherine Anna. "NMR studies reveal the kinetics and thermodynamics of hairpin formation /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/8611.
Full textWilliamson, Mark Allen. "Thermodynamic and kinetic studies of sulfur geochemistry." Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/38485.
Full textRennie, Timothy J. "Numerical and experimental studies of a double-pipe helical heat exchanger." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85642.
Full textResults from the numerical trials show that the inner Nusselt numbers in the heat exchanger were similar to literature data, despite the different boundary conditions. Nusselt numbers in the annulus were correlated to a modified Dean number. It was shown that the thermal resistance in the annulus to be the greatest limiting factor for the heat transfer, and heat transfer rates could be increased by increasing the inner tube diameter.
The Prandtl number was shown to affect the inner Nusselt number; however the effects were much greater at low Dean numbers. These differences were attributed to the difference in the developing thermal and hydrodynamic boundary layers. The studies with the thermally dependent thermal conductivities showed that the Nusselt number correlated well with a modified Graetz number.
Thermally dependent viscosity had little effect on the heat transfer; however it affected the pressure drop. Furthermore, it was shown that by keeping the flow rate in the inner tube or the annulus constant, the pressure drop in that section can be affected by changes in the flow rate in the opposite section, due to the change in the heat transfer rate and hence the average temperature and viscosity of the fluid. Non-Newtonian fluids showed little effect on the heat transfer rates, though they significantly affected the pressure drop relations.
The uniformity of the residence time and the temperature distribution were both increased in the inner tube with increasing flow rates. It was shown that a smaller gap size in the annulus resulted in more uniform residence times. Temperature distributions in the inner tube and the annulus were affected by changes in the flow velocity in the opposite section, with lower flow rates resulting in more uniform temperature distributions. Implications of using parallel flow versus counterflow, heating versus cooling, and flow rate are discussed.
Overall heat transfer coefficients and Nusselt numbers were calculated for the experimental data. The inner and annulus heat transfer coefficients were determined using Wilson plots. The results were compared to the numerical data and literature values and showed reasonable agreement. (Abstract shortened by UMI.)
Frederiksen, Joorgen Segerlund. "Theoretical studies in high energy physics and atmospheric dynamics /." Title page, introduction and contents only, 1987. http://web4.library.adelaide.edu.au/theses/09SD/09sdf852.pdf.
Full textBhuiyan, Golam Mohammed. "Theoretical studies of the liquid structure and thermodynamics of transition metals." Thesis, University of East Anglia, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357163.
Full textMokdad, Audrey. "Time-resolved thermodynamics studies of heme signaling proteins and model systems." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003063.
Full textDavidson, James Prentice. "Calorimetric and structural studies of 1,2,3-trisubstituted cyclopropanes as conformationally constrained peptide mimics /." Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3008309.
Full textLewis, Amanda. "Fundamental studies of the chemical vapour deposition of graphene on copper." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/fundamental-studies-of-the-chemical-vapour-deposition-of-graphene-on-copper(f85feb54-5994-4201-b400-c622f4d7b216).html.
Full textSmit, Reneé. "The nature of engineering and science knowledge in curriculum: a case study in thermodynamics." Doctoral thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/25532.
Full textMonga, Zinki. "THERMODYNAMIC STUDIES ON THE SYNTHESIS OF NITRIDES AND EPITAXIAL GROWTH OF INGAN." Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3881.
Full textM.S.M.S.E.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Materials Science & Engr MSMSE
Skorobogatiy, Maksim. "Theoretical studies of the thermodynamics and kinetics of proteins : application to protein folding." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ44280.pdf.
Full textAbyzov, Anton. "Nuclear Magnetic Resonance Studies of the Dynamics and Thermodynamics of Intrinsically Disordered Proteins." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAY026/document.
Full textIntrinsically disordered proteins (IDPs) are highly flexible heteropolymers, implicated in important cellular activities (signal transduction, molecular recognition, transcription, translation, etc.) and representing potential drug targets against cancer and neurodegenerative diseases, whose dynamic modes define their biological function. Although the conformational states sampled by IDPs are relatively well understood, essentially nothing is known about the associated dynamic timescales. In this study we investigate the conformational behavior of the intrinsically disordered C-terminal domain of the nucleoprotein of Sendai virus (NTAIL), which interacts with the PX domain of the phosphoprotein. The interaction site has been shown to sample an equilibrium of discrete helices in the free state, which forms an encounter complex implicating the stabilization of one of the helical conformers upon interaction with PX, prior to diffusing on the surface of PX and engaging in the actual binding site. However, very little is known about the timescales of chain motions, which surely play a role in the interaction kinetics, in particular in terms of the on-rate of the interaction. This 124 amino acid protein also provides a good model system, containing long unfolded domains with chain-like dynamics and regions with residual structure. The measurement of extensive set of coherent relaxation rates at multiple magnetic fields, multiple temperatures and in three different length constructs of the same IDP has allowed us to characterize the dynamic nature of NTAIL in unprecedented detail. By analyzing the relaxation data using extended model-free approach, we show that fast (≤ 50 ps) components of the correlation function report on librational motions. A dominant mode occurs on timescales around one nanosecond, apparently reporting on backbone sampling within Ramachandran sub-states, while a slower component (5-25 ns) reports on segmental dynamics dominated by the chain-like nature of the protein. The ability to delineate intrinsic modes and timescales will improve our understanding of the behavior and function of IDPs
Abdel, Aziz May. "Kinetic and Thermodynamic Studies of Thrombin Inhibitors." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/2956.
Full textPackwood, Daniel Miles. "Theoretical and Experimental Studies of the Gas-Liquid Interface." Thesis, University of Canterbury. Department of Chemistry, 2010. http://hdl.handle.net/10092/4618.
Full textSmall, Meagan. "Photothermal Studies of Carboxymyoglobin." Scholar Commons, 2010. https://scholarcommons.usf.edu/etd/1775.
Full textBhagan, Salome. "REACTIVITY AND EQUILIBRIUM THERMODYNAMIC STUDIES OF IRIDIUM PORPHYRINS IN WATER AND ALCOHOL." Diss., Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/213129.
Full textPh.D.
Environmental and energy issues have stimulated renewed interest in utilizing both water and methanol as reagents and reaction mediums. Our current interest is to evaluate the scope of group nine organometallics and establish thermodynamic parameters for their reactivity in aqueous solvent. A comprehensive thermodynamic database for a wide scope of organo-rhodium transformations in a range of reaction media including benzene, water, and methanol has been well established by our group. Aqueous solutions of rhodium porphyrin have been determined to manifest an exceptional range of substrate reactions with carbon monoxide, dihydrogen, olefins, methanol and aldehydes. This study will focus on expansion of the thermodynamic database to all the group nine metals, particularly the iridium porphyrin systems in both water and methanol. Substrate reactivity and development of new mechanistic strategies for the conversion of carbon monoxide, alkanes, and alkenes to organic oxygenates are central objectives. Water/Methanol soluble porphyrin iridium complexes including iridium tetrakis(p-sulfonatophenyl)porphyrin ((TSPP)Ir) and iridium tetrakis(3,5-sulfonatomesityl)porphyrin ((TMPS)Ir) derivatives can be prepared by sulfonation of tetra phenyl porphyrin (H2TPP) and tetra mesityl porphyrin (H2TMP). The reactivity of dihydrogen with aqueous solutions of iridium(III) tetrakis(p-sulfonatophenyl)porphyrin ((TSPP)Ir(III)) complexes produce equilibrium distributions between six iridium species including iridium hydride ([(TSPP)Ir-D(D2O)]-4), iridium(I) ([(TSPP)IrI(D2O)]-5), and iridium (II) dimer ([(TSPP)IrII(D2O)]2-8) complexes. Each of these types of iridium porphyrin species including Ir(I), Ir(II), Ir(III), Ir-H, and Ir-OH function as precursors for a range of organometallic substrate reactions. A primary objective is to define the quantitative relationships pertaining to the distribution of species in aqueous solution as a function of the dihydrogen and hydrogen ion concentrations through direct measurement of five equilibrium constants along with free energy changes of coordinated water and free energy changes of reactions of dihydrogen in water. Reactivity, kinetics and evaluation of equilibrium thermodynamics, including the reactions of iridium hydroxide and methoxide with olefins to produce beta-hydroxyalkyl and beta-methoxyalkyl complexes, reactions of iridium hydride and olefins to produce iridium alkyl complexes, and reactions of iridium hydride with carbon monoxide to produce iridium formyl [Ir-CHO] complexes are also objectives of this research. Another research goal is the design and synthesis of diporphyrin ligands that form dimetal complexes capable of preorganizing transition states for substrate reactions that involve two metal centers. Dirhodium dimetalloradical complexes are observed to manifest large rate increases over mono-metalloradical activation reactions of hydrogen, methane, and other small molecule substrates. In this study, synthesis of diporphyrin (bisporphyrin) ligands and other ligands which will permit dimetallo complexes like anti-aromatic [14]annulene and low steric porphine ligands will be also be examined.
Temple University--Theses
Shough, Anne Marie. "Quantum chemistry studies of catalytic and photocatalytic materials transition metal substitution, active sites, thermodynamics and reaction mechanisms /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 260 p, 2008. http://proquest.umi.com/pqdweb?did=1597619031&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Full textImler, Gregory H. "Reactivity, Characterization, Equilibrium Thermodynamics and Hetero-bimetallic Studies of Tridentate and Tetradentate Complexes Relevant to Syngas Catalysis." Diss., Temple University Libraries, 2014. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/302256.
Full textPh.D.
The unifying objective of this work is the study of model systems that will assist in the development of new metal catalysts capable of converting carbon monoxide and hydrogen (syngas) into organic oxygenates at mild temperature and pressure. The selective catalytic transformation of carbon monoxide and hydrogen to liquid fuels and chemical feedstocks represents a major "Grand Challenge" of catalysis science. A core objective is the study of a macrocycle that is related to a porphyrin ligand in order to circumvent some of the disadvantages of utilizing porphyrins in catalysis. The rhodium complex of the macrocycle dibenzotetramethylaza[14]annulene ([(tmtaa)Rh]2]) was reacted with a series of small molecules relevant to CO reduction and hydrogenation. Several complexes were formed that demonstrated the ability to partially reduce and hydrogenate carbon monoxide, including the dirhodium ketone (Rh-C(O)-Rh) and an example of a thermodynamically favorable metal formyl complex ((tmtaa)Rh-C(O)H). An important feature of this work is the measurement of thermodynamic data to provide experimental benchmarks for obtaining key species in CO reduction and hydrogenation. A thorough study of the (tmtaa)Rh system will help in identifying structural features that assist or hinder CO hydrogenation. All reactions are monitored by 1H NMR which permits determination of solution thermodynamics from equilibrium constants obtained by NMR peak integrations. DFT calculations have supplemented experimental results by providing estimates to compare with the experimentally determined thermodynamic data. These computations also provide insight into the structures and thermodynamics of species that cannot be observed directly such as short lived intermediates and thermodynamically unfavorable products. Heterobimetallic complexes of (tmtaa)Rh* with a second metal radical have been utilized to attempt to convert CO to organic products. Reactivity with CO and H2 has been accomplished, with most of these metal systems providing (tmtaa)Rh-C(O)H and M-H as final products. These systems are now ideally set up for catalysis in which M-H can deliver hydrogen to reduce and hydrogenate the rhodium formyl unit. Performing these reactions at high pressures of CO/H2 or with a more sterically hindered analog of tmtaa may provide the conditions necessary for catalysis. Reactivity, thermodynamic and computational studies have been used to analyze and compare bond energies in this current work with previous studies accomplished in the Wayland group. These comparisons permit further understanding into the factors that control bond strength, guiding future studies and allowing tuning of bond strengths based on choice of conditions for a catalytic process. This research has resulted in a more complete understanding of the factors that control the favorability of various intermediates in CO reduction and hydrogenation and the application of these results can be used to guide the next generation of metal ligand systems that will yield organic oxygenates at mild conditions.
Temple University--Theses
Deegan, Brian J. "Biophysical Studies of the Binding of ERα Nuclear Receptor to DNA." Scholarly Repository, 2011. http://scholarlyrepository.miami.edu/oa_dissertations/579.
Full textGUPTA, VINEET K. "EXPERIMENTAL AND THEORETICAL STUDIES IN REVERSE OSMOSIS AND NANOFILTRATION." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1061233200.
Full textFabbri, Marco. "Neutronics analysis and thermodynamics studies of several DEMO breeding blankets for the development of the AINA safety code." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/552957.
Full textEn el año 2050 la producción de energía podría estar distribuida principalmente entre fuentes renovables lideradas por la fusión nuclear que potencialmente puede proveer grande cantidades de energías para largos tiempos, sin afectar considerablemente el ambiente. Desafortunadamente, la fusión nuclear requiere aun numerosos desarrollos para demostrar entre otros la validez del diseño y la seguridad nuclear, argumentos que son tratados en esta tesis doctoral. Durante los últimos diez años, el Nuclear Engineering Research Group (NERG-UPC) ha estado desarrollando un código de seguridad nuclear denominado AINA (Analyses of IN-vessel Accidents) para evaluar los transitorios de plasma-pared en los TOKAMAK, reactores de fusión nuclear a confinamiento magnético, en caso LOCA ex-vessel y accidentes de combustible. El programa determina las consecuencias en componentes in-vessel como la temperatura de los mismos y su integridad. Teniendo en cuenta la ewlución de las tecnologías, un plan de renovación para AINA ha sido puesto en marcha incluyendo dos tareas específicas en esta tesis.(i) La definición, estandarización y validación de una metodología para el desarrollo de nuevas versiones de AINA para obtener modelos simplificados y fiables que puedan estimar de manera precisa el comportamiento de los componentes estudiados. (ii) El rediseño, generalización y optimización de las rutinas termo-hidráulicas para la determinación de los perfiles de temperatura evaluados por AINA, en caso estacionario o transitorios con el fin de remplazar las anteriores. Así mismo, dichas funciones han sido evaluadas y verificadas a través de comparaciones directas a software comerciales como ANSYS Fluent. De esta manera, AINA ha sido casi completamente replanteado, mejorado y consolidado con especial atención a la documentación, comentarios y verificación en línea con los estándares de software actuales. Novedosas técnicas han sido introducidas para añadir la capacidad de modelación y su capacidad.
Wang, Zhengrong Burnett Donald S. "Oxygen isotope studies of the petrogenesis of Hawaiian lavas and a theoretical study on equilibrium thermodynamics of multiply-substituted isotopologues /." Diss., Pasadena, Calif. : California Institute of Technology, 2005. http://resolver.caltech.edu/CaltechETD:etd-05192005-000025.
Full textFredriksson, Patrik. "Thermodynamic Studies of the Fe-Pt System and “FeO”-Containing Slags for Application Towards Ladle Refining." Doctoral thesis, KTH, Materials Science and Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3630.
Full textIn the present work, the thermodynamic activites of ironoxide, denoted as "FeO" in the slag systems Al2O3-"FeO", CaO-"FeO", "FeO"-SiO2, Al2O3-"FeO"-SiO2, CaO-"FeO"-SiO2and "FeO"-MgO-SiO2were investigated by employing the gasequilibration technique at steelmaking temperatures. Thestrategy was to expose the molten slag mixtures kept inplatinum crucibles for an oxygen potential, determined by aCO/CO2-ratio. A part of the iron reduced from the "FeO"in the slag phase was dissolved into the Pt crucible.
In order to obtain the activites of "FeO", chemical analysisof the quenched slag samples together with thermodynamicinformation of the binary metallic system Fe-Pt is required.Careful experimental work was carried out by employing asolid-state galvanic cell technique as well as calorimetricmeasurements in the temperature ranges of 1073-1273 K and300-1988 K respectively. The outcome of these experiments wasincorporated along with previous studies into a CALPHAD-type ofthermodynamic assessment performed with the Thermo-Calcsoftware. The proposed equilibrium diagram enabledextrapolation to higher temperatures.
The experimentally obtained activites of "FeO" in thepresent work, along with earlier investigations were assessedwith the KTH slag model, THERMOSLAG©. New binaryparameters were evolved and incorporated in THERMOSLAG©.The present model calculations are compared with othercommercially available software such as F*A*C*TandThermo-Calc. The validity of the modified model wasinvestigated by measurements carried out in case of Al2O3-"FeO"-SiO2, CaO-"FeO"-SiO2and "FeO"-MgO-SiO2ternary slags. The potential of the model tocompute the activities in the case of multicomponent slags wasdemonstrated.
A correlation between the activity of a metallic oxide in aternary slag system and the sulphide capacity of the slag wasinvestigated by using the solubility of sulphur in the binarysystems CaO-SiO2and Al2O3-CaO along with the sulphide capacity of the Al2O3-CaO-SiO2system. The estimated values of the activitieswere found to be in good agreement with the measured values.This correlation also gives the possibility to elucidate theapplicability of Henry's law to the activity of a metallicsulphide and to determine the order in the affinity of a cationto sulphur between two metallic oxides in a slag.
Model calculations were performed with THERMOSLAG©, by using plant data from the ladle refiningprocess at OVAKO Steel, Hofors, Sweden. It was found thatoxygen estimations in the metal from the "FeO" analyses ofslags, obtained by conventional sampling and analysis methodwere less reliable. Reliable estimation of the oxygen levelsutilising the sulphur partition between the slag and the metalwere carried out using THERMOSLAG© software.
Keywords:Thermodynamics, Activity, Galvanic cell,Calorimetry, Gas equilibration technique, Iron-platinum alloys,FeO, Slags, Modelling, Ladle
Isaksson, Johan. "Studies on Nucleic Acids – Structure and Dynamics." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5867.
Full textChen, Yiqiang. "High-resolution microstructural and microanalysis studies to better understand the thermodynamics and diffusion kinetics in an advanced Ni-based superalloy RR1000." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/highresolution-microstructural-and-microanalysis-studies-to-better-understand-the-thermodynamics-and-diffusion-kinetics-in-an-advanced-nibased-superalloy-rr1000(1d4e96e0-b362-484e-82cb-bec18cab850b).html.
Full textMishima, Hirokazu. "Studies Based on Statistical Mechanics for Mechanism of Multidrug Efflux of AcrA/AcrB/TolC." Kyoto University, 2015. http://hdl.handle.net/2433/199416.
Full textWicky, Basile Isidore Martin. "Biophysical studies of protein assemblies." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/288004.
Full textMaximo, Guilherme José 1982. "Lipid thermodynamics = new perspectives on phase studies for applications in engineering = Termodinâmica de lipídios: novas perspectivas em estudos de fases para aplicações em engenharia." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255144.
Full textTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-24T10:06:55Z (GMT). No. of bitstreams: 1 Maximo_GuilhermeJose_D.pdf: 6364914 bytes, checksum: 716122d30b63141c35ee3d3c3305de17 (MD5) Previous issue date: 2014
Resumo: Para o desenvolvimento de chocolates, manteigas, molhos para salada, cremes cosméticos, medicamentos ou biocombustíveis, assim como na otimização de processos de extração, refino, fracionamento, cristalização e produção de energia, os fenômenos de transição de fases dos sistemas lipídicos são temas, há muito tempo, de diversos trabalhos na literatura. O objetivo desses trabalhos tem sido avaliar como a composição dos produtos altera as suas propriedades físico-químicas e em especial aquelas relacionadas aos processos de fusão. De fato, alterações na temperatura exercem um grande impacto na estrutura cristalina da fase sólida dos sistemas graxos e, consequentemente, nas propriedades sensoriais e reológicas dos produtos. Essas alterações produzem comportamentos termodinâmicos tão variados que a determinação do equilíbrio de fases sólido-líquido desses sistemas representa um grande desafio. Não obstante, quanto maior a complexidade do sistema, menor é a compreensão do seu comportamento. Ou seja, apesar do grande número de trabalhos presentes na literatura envolvidos na investigação dos fenômenos de fusão de sistemas lipídicos, novos dados experimentais e abordagens teóricas para a modelagem dos diagramas são necessários para sua compreensão. Neste contexto, este trabalho teve dois objetivos principais. O primeiro relacionado à determinação e análise de diagramas de fases sólido-líquido de sistemas lipídicos binários de interesse para a indústria. O segundo foi desenvolver alternativas teóricas para aprimorar a representação dos diagramas de fases baseado em abordagens termodinâmicas clássicas. Portanto, onze sistemas binários compostos por triacilgliceróis, ácidos graxos e álcoois graxos foram avaliados. Esses sistemas são potenciais agentes de estruturação, formação de organogéis, produção e armazenamento de energia na indústria de alimentos, farmacêutica e de materiais. Os diagramas de equilíbrio sólido-líquido dessas misturas apresentaram comportamentos distintos, dependentes da formação de fases sólidas miscíveis ou imiscíveis e da não-idealidade do sistema. Além disso, foram estudados quatro sistemas formados a partir da reação ácido-base de Brønsted entre ácidos graxos e etanolaminas. Neste caso, a formação de líquidos iônicos próticos cristalinos com grande habilidade para auto-organização e comportamento não-Newtoniano singular podem atuar como auxiliares em diversas aplicações químicas e farmacêuticas. O problema imposto pela miscibilidade da fase sólida na construção dos diagramas de fases foi superado pela implementação de um algoritmo para a resolução de um sistema de equações não-lineares baseado nas equações fundamentais do equilíbrio sólido-líquido. O objetivo do algoritmo "Crystal-T" foi determinar a temperatura em que o primeiro e o último cristal se fundem durante o aquecimento do sistema. Para isso, a não-idealidade de ambas as fases líquida e sólida foi avaliada utilizando equações baseadas na energia de Gibbs em excesso, incluindo o método de contribuição de grupos UNIFAC, para o cálculo dos coeficientes de atividade. Considerando o aumento da produção mundial e do consumo de óleos e gorduras, este trabalho, a partir de demandas emergentes da indústria e da pesquisa científica, contribuiu na superação de alguns obstáculos relacionados à compreensão do equilíbrio de fases sólido-líquido de sistemas lipídicos para a engenharia de produtos e processos
Abstract: The phase transition phenomena of lipidic systems have long since been evaluated by several works in literature for developing chocolate, butters, dressings, spreads, cosmetic creams, medicines or biofuels as well as for optimizing processes such as extraction, refining, fractionation, crystallization or energy production. The aim of such works has been to answer how the products¿ composition can affect their physicochemical characteristics especially that related to the melting processes. In fact, changes in temperature highly impact the crystalline structure of fatty systems¿ solid phase and, consequently, in the sensorial and rheological properties of the products. These changes led to so many thermodynamic behaviors that the determination of the solid-liquid equilibrium of these systems can configure a particular challenge. However, the greater the complexity of the system the lower the understanding of its behavior. In other words, despite the number of works in literature involved in the investigation of the melting phenomena of lipidic systems, there is still a lack of experimental data and modeling approaches for their understanding. In this context, this work was conducted with two main goals. The first was focused on the measurement and comprehension of the solid-liquid equilibrium phase diagrams of lipidic binary systems of industrial interest. The second was aimed at the development of theoretical alternatives to improve the phase diagram description based on classical thermodynamic approaches. Thus, eleven binary systems composed by triacylglycerols, fatty alcohols and fatty acids were evaluated. Such mixtures are potential structuring, organogelating and energy storing agents for food, pharmaceutical and materials industry. The solid-liquid phase diagrams of these mixtures presented distinct behaviors depending on the formation of immiscible or miscible solid phases and the non-ideality of the system. Also, four systems built through a Brønsted acid-base reaction between fatty acids and ethanolamines were also evaluated. In this case, the formation of protic ionic liquid crystals with high self-assembling ability and marked non-Newtonian behavior are promising for pharmaceutical and chemical applications. The problem imposed by the partial miscibility of the solid phase in the construction of the phase diagrams was overtaken by the implementation of an algorithm based on the resolution of a non-linear equations system built by the solid-liquid equilibrium fundamental equations. The "Crystal-T" algorithm was aimed at the determination of the temperature at which the first and last crystal melts during the heating process. For this, the non-ideality of both liquid and solid phases was evaluated using excess Gibbs energy equations, including the group-contribution UNIFAC model, for the calculation of the activity coefficients. Taking into account the growing increase of the world production and consumption of fat and oils, this work, from industrial and academic emerging demands, contributed to overtake some barriers on the understanding of the solid-liquid phase equilibrium of lipidic mixtures for products and process engineering
Doutorado
Engenharia de Alimentos
Doutor em Engenharia de Alimentos
Farooqi, Mohammed Junaid. "METHODS FOR IN SITU PIEZOPHYSIOLOGICAL STUDIES: OPTICAL SECTIONING VIA STRUCTURED ILLUMINATION AND FLUORESCENCE BASED CHARACTERIZATION OF NADH CONFORMATION." Oxford, Ohio : Miami University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1249225952.
Full textLorenzo, Ros Sara de. "Single molecule studies in a temperature-jump optical trap." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/286174.
Full textEn el campo de la biofísica, el estudio de las características termodinámicas de las biomoléculas, como ADN, ARN o proteínas, permite conocer más sobre los componentes básicos de la vida. La caracterización termodinámica de las biomoléculas nos proporciona pistas sobre sus funciones y capacidades dentro de un organismo vivo. La caracterización termodinámica de los ácidos nucleicos describe como la temperatura afecta la estabilidad y la estructura de la doble cadena de ADN. La temperatura de melting del ADN (TM) se define como la temperatura a la cual la mitad de las moléculas de ADN disueltas en una solución se encuentran en configuración de doble cadena (dsDNA) y la otra mitad se encuentra en la configuración de cadena individual (ssDNA). Conociendo el valor de la TM es posible determinar experimentalmente los parámetros termodinámicos: Delta-G, Delta-H y Delta-S. Viceversa, cuando los parámetros termodinámicos de la secuencia de un ácido nucleico es conocido, la TM puede ser predecida. Este efecto tiene importantes aplicaciones en técnicas de biología molecular como PCR (en inglés Polymerase chain reaction) o secuenciación. Tradicionalmente las propiedades termodinámicas del ADN han sido medidas utilizando técnicas de volumen como calorimetría o absorbancia de UV. En ambos casos la TM ha sido calculada modificando la temperatura o el pH de toda la muestra. En las pasadas dos décadas, las técnicas de espectroscopía de fuerzas sobre moléculas individuales, han sido reconocidas como técnicas de un gran valor y precisión cuyos resultados en el estudio de la caracterización termodinámica pueden ser considerados perfectamente complementarios a los medidos en técnicas de volumen. La técnica de atrapamiento óptico es una técnica experimental la cual permite ejercer fuerza sobre una partícula micrométrica utilizando la presión de radiación de la luz. Las minipinzas (en inglés minitweezers) es una nueva generación a los instrumentos de pinzas ópticas. Este instrumento puede ser usado para ejercer y medir fuerzas en un rango de entre 1-200pN y con una resolución en fuerza y distancia sin precedentes. El atrapamiento óptico es muy útil en el campo de la biología molecular permitiendo ejercer fuerzas sobre biomoléculas individuales enganchadas. Esta técnica es usada para llevar a cabo experimentos de estiramiento sobre moléculas individuales permitiendo el estudio de las propiedades mecánicas, termodinámicas y cinéticas de la molécula bajo estudio. El experimento de unzipping o melting mecánico es un proceso que consiste en separar las dos hebras de la dsDNA hasta que los enlaces entre los pares de bases complementarios son deshechos y la molécula se convierte en ssDNA. En este caso la fuerza es usada como medio para abrir la molécula, en vez de la temperatura o el pH como en otras técnicas. Pasados experimentos han mostrado que podemos obtener mejor resolución utilizando técnicas de moléculas individuales que utilizando técnicas en volumen. Aunque la fuerza de unzipping nos proporciona una estimación directa de Delta-G a temperatura ambiente, para poder extraer el valor de TM requiere conocer las contribuciones de Delta-H y Delta-S y hasta ahora no ha sido posible. Para llevar a cabo una completa caracterización termodinámica de ácidos nucleicos es importante conocer ambas magnitudes (Fuerza y Temperatura). El mejor camino para hacer este análisis es llevar a cabo experimentos de unzipping sobre moléculas individuales de ADN a diferentes temperaturas. Por ello hemos desarrollado un novedoso instrumento de pinzas ópticas con un controlador de temperatura que nos permite modificar y cambiar la temperatura de manera local y rápida. Se ha usado un específico láser calentador con una longitud de onda con una alta absorción en agua que permite cubrir un amplio rango de temperaturas. Este instrumento nos permite grabar diversas curvas de fuerza/extensión para una molécula individual a varias temperaturas con una buena estabilidad térmica y mecánica. Este diseño tiene ciertas mejoras para reducir la convección, el cual ha sido un grave problema en previos equipos calentados a través de un láser. Este equipo ha sido usado para hacer experimentos de ADN, lo que nos ha permitido hacer un análisis promediado de Delta-G, Delta-S y Delta-H entre pares de bases en un rango de temperatura entre 5ºC y 50ºC.
Strach, Michal. "In situ studies of uranium-plutonium mixed oxides : Influence of composition on phase equilibria and thermodynamic properties." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4044.
Full textDue to their physical and chemical properties, mixed uranium-plutonium oxides are considered for fuel in 4th generation nuclear reactors. In this frame, complementary experimental studies are necessary to develop a better understanding of the phenomena that take place during fabrication and operation in the reactor. The focus of this work was to study the U Pu–O phase diagram in a wide range of compositions and temperatures to ameliorate our knowledge of the phase equilibria in this system. Most of experiments were done using in situ X-ray diffraction at elevated temperatures. The control of the oxygen partial pressure during the treatments made it possible to change the oxygen stoichiometry of the sample, which gave us an opportunity to study rapidly different compositions and the processes involved. The experimental approach was coupled with thermodynamic modeling using the CALPHAD method, to precisely plan the experiments and interpret the obtained results. This approach enabled us to enhance the knowledge of phase equilibria in the U–Pu–O system
Choudhury, Pabitra. "Theoretical and experimental study of solid state complex borohydride hydrogen storage materials." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003164.
Full textPrilliman, Gerald Stephen. "Synchrotron X-ray diffraction studies of phase transitions and mechanical properties of nanocrystalline materials at high pressure." Berkeley, Calif. : Oak Ridge, Tenn. : Lawrence Berkeley National Laboratory ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2003. http://www.osti.gov/servlets/purl/825137-DcNEaM/native/.
Full textPublished through the Information Bridge: DOE Scientific and Technical Information. "LBNL--55022" Prilliman, Gerald Stephen. USDOE Director. Office of Science. Office of Basic Energy Sciences (US) 09/01/2003. Report is also available in paper and microfiche from NTIS.
Shelton, John. "Thermophysical Characterization of Nanofluids Through Molecular Dynamic Simulations." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3343.
Full textRendell, Benjamin William Spiby. "Thermodynamic studies of glass refining." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619563.
Full textButt, Michael David. "Macromolecular thermodynamics studied by titration calorimetry." Thesis, University of Leicester, 1994. http://hdl.handle.net/2381/34042.
Full textConn, Graeme Leslie. "Structural and thermodynamic studies of RNA." Thesis, University of Edinburgh, 1996. http://hdl.handle.net/1842/12169.
Full textAmezawa, Koji. "Irreversible Thermodynamic Studies on Electrochemical Systems." Kyoto University, 1998. http://hdl.handle.net/2433/77878.
Full textWhiteway, Clare Ann. "Structural and thermodynamic studies on retinal proteins." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240487.
Full textJackson, Philip R. "Thermodynamic studies of binary mixtures involving aromatic fluorocarbons." Thesis, University of Leicester, 1986. http://hdl.handle.net/2381/33750.
Full textDing, Shu. "Thermodynamic studies on iron-sulfur cluster assembly proteins." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1316472363.
Full textBoclair, Joseph W. (Joseph Walter). "Thermodynamic and Structural Studies of Layered Double Hydroxides." Thesis, University of North Texas, 1998. https://digital.library.unt.edu/ark:/67531/metadc278144/.
Full textMassis, Sameer. "Biophysical studies and thermodynamic analysis of cathepsin B interactions." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0026/MQ50833.pdf.
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