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1
Cabrera, Córdova César Raymundo. "Quantum liquid droplets in a mixture of Bose-Einstein condensates." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/663331.
Full textAbstract:
In this thesis, we report on the design and construction of a quantum simulator experiment using quantum gases in Spain. This experiment exploits mixtures of the three isotopes of potassium, which give access in an original approach to the study of Bose-Bose or Bose-Fermi mixtures using the same experimental setup.
We validate our experimental setup with the observation of a Bose-Einstein condensate (BEC) of 41K and 39K. Moreover we observe the dual Bose-Einstein condensation of 39K–41K. These results represents the first observation of BECs in Spain and give access to a novel quantum degenerate mixture in the field. Since the control of interactions in our experiment are crucial, we characterize the scattering properties of the 39K–41K mixture, and spin mixtures of 39K and 41K.
In addition, using a spin mixture of 39K BEC, we report on the observation of a novel state of matter: a composite quantum liquid droplet. This dilute quantum droplet is a liquid-like cluster of ultra-cold atoms self-trapped by attractive mean-field forces and stabilized against collapse by repulsive beyond mean-field many-body effects. This system follows the original proposal where D. Petrov predicted the formation of self-bound liquid droplets in mixtures of Bose-Einstein condensates.
In the first series of experiments, we have observed the formation of quantum droplets in a regime where the Bose-Bose mixture should collapse from the mean-field perspective.We directly measure the droplet size and ultra-low density via high-resolution in situ imaging, and experimentally confirm their self-bound nature.We demonstrate that the existence of these droplets is a striking manifestation of quantum fluctuations. These droplets do not exist in single-component condensates with described with contact interactions. Finally, we observe that for small atom numbers, quantum pressure dissociates the droplets and drives a liquid-to-gas transition, which we map out as a function of interaction strength.
These measurements open an intriguing point of investigation: the difference existing between droplets and bright solitons. In the second series of experiments, we address it by placing the mixture in an optical waveguide, realizing a system that contains both composite bright solitons and quantum liquid droplets. In analogy to non-linear optics, the former can be seen as one-dimensional matter-wave solitons stabilized by dispersion, whereas the latter corresponds to highdimensional solitons stabilized by a higher order non-linearity. We find that depending on atom number, interaction strength and confinement, solitons and droplets can be smoothly connected or remain distinct states coexisting only in a bi-stable region. We measure their spin composition, extract their density for a broad range of parameters, and map out the boundary of the region separating solitons from droplets.
Our experiments demonstrate a novel type of ultra-dilute quantum liquid, stabilized only by contact interactions. They provide an ideal platform for benchmarking complex quantum many-body theories beyond the mean-field approximation in a quantum simulation approach. Furthermore, they constitute a novel playground to explore experimentally self-bound states stabilized by unconventional higher order nonlinearities, relevant in non-linear optics.En este trabajo de tesis se reporta el diseño y la construcción de uno de los experimentos pioneros en España que permite realizar simulaciones cuánticas usando átomos ultra fríos. En este experimento se enfrían hasta alcanzar la degeneración cuántica los tres diferentes isotopos de potasio los cuales permiten, de manera particular y original, el estudio de mezclas cuánticas degeneradas de tipo Bose-Bose o Bose-Fermi. El funcionamiento del experimento es validado por medio de la producción de condensados de Bose-Einstein de 41K y 39K. Además, se reporta la condensación de la mezcla degenerada 41K - 39K, la cual no había sido previamente reportada en la literatura. Estos resultados son los primeros de su tipo en España y por lo tanto abren un amplio panorama en el estudio de fenómenos cuánticos en el país. La mezcla cuántica reportada en esta tesis permite acceder a sistemas cuánticos novedosos en el campo de átomos fríos. El control de las interacciones atómicas es una herramienta ampliamente usada en el campo, por lo cual se han caracterizado las propiedades de dispersión en esta nueva mezcla, así como en diferentes mezclas de espín entre los isotopos 41K y 39K. El resultado más importante de esta tesis reside en la creación de un nuevo estado de la materia: una gota liquida cuántica ultra-diluida. Esta gota cuántica se compone de una mezcla de dos estados diferentes de espín de 39K. Este líquido se encuentra ligado por sí mismo debido a la compensación de las fuerzas atractivas de campo con el carácter repulsivo de efectos cuánticos que van más allá de la aproximación de campo medio. Este sistema sigue la idea original de D. Petrov, esta propone la formación de líquidos cuánticos usando mezclas de condensados de Bose-Einstein. En la primera serie de experimentos, hemos observado la formación de gotas cuánticas en un régimen donde una mezcla de Bose debería de colapsar de acuerdo con teorías de campo medio. Se ha medido su tamaño y ultra-baja densidad por medio de imágenes in situ. De esta manera confirma cómo este líquido permanece ligado por si mismo en la ausencia de confinamiento externo. Hemos demostrado que la existencia de estas gotas cuánticas se debe a una manifestación sorprendente de las fluctuaciones cuánticas. Finalmente hemos observado cómo debido a la presencia de la presión cuántica, debajo de un numero critico de átomos el sistema se disocia en gas dando lugar a una transición cuántica liquido-gas. Esta transición se ha medido experimentalmente como función de las interacciones atómicas entre los átomos. Estas mediciones traen consigo una pregunta intrigante: ¿Cuál es la diferencia entre nuestras gotas cuánticas y los ya conocidos solitones de materia? En una segunda serie de experimentos, hemos dado respuesta a esta interrogante al estudiar las propiedades de una mezcla de Bose confinada en una guía óptica. En este tipo de geometría ambos estados pueden existir. En analogía a sistemas ópticos no-lineales, solitones son sistemas estabilizados por efectos de dispersión, mientras las gotas cuánticas corresponden a solitones de más alta dimensión estabilizadas por efectos no lineales de alto orden. Hemos encontrado que, dependiendo del número de átomos, fuerza de interacción y confinamiento, solitones y gotas cuánticas son dos estados cuánticos que pueden estar conectados, permanecer como dos estados distintos, o coexistir en una región de bi-estabilidad. Se ha medido su composición de espín, densidad del sistema y encontrado experimentalmente la frontera que separa ambos sistemas. En conclusión, los experimentos mostrados en esta tesis demuestran la existencia de un nuevo liquido cuántico ultra-diluido estabilizado únicamente por interacciones de contacto. Su existencia es puramente debida a las fluctuaciones cuánticas presentes en el sistema. Este sistema provee una plataforma ideal para el estudio y la comprensión de teorías cuánticas más complejas las cuales van más allá de la aproximación de campo medio.
2
Chakrabarti, Dwaipayan. "Slow Dynamics In Soft Condensed Matter : From Supercooled Liquids To Thermotropic Liquid Crystals." Thesis, Indian Institute of Science, 2006. https://etd.iisc.ac.in/handle/2005/292.
Full textAbstract:
This thesis, which contains fourteen chapters in two parts, presents theoretical and computer simulation studies of dynamics in supercooled liquids and thermotropic liquid crystals. These two apparently diverse physical systems are unified by a startling similarity in their complex slow dynamics. Part I consists of six chapters on supercooled liquids while Part II comprises seven chapters on thermotropic liquid crystals. The fourteenth chapter provides a concluding note.
Part I starts with an introduction to supercooled liquids given in chapter 1. This chapter discusses basic features of supercooled liquids and the glass transition and portrays some of the theoretical frameworks and formalisms that are widely recognized to have contributed to our present understanding.
Chapter 2 introduces a new model of binary mixture in order to study dynamics across the supercooled regime. The system consists of an equimolar mixture of the Lennard-Jones spheres and the Gay-Berne ellipsoids of revolution, and thus one of its components has orientational degrees of freedom (ODOF). A decoupling between trans-lational diffusion and rotational diffusion is found to occur below a temperature where the second rank orientational correlation time starts showing a steady deviation from the Arrhenius temperature behavior. At low temperatures, the optical Kerr effect (OKE) signal derived from the system shows a short-to-intermediate time power law decay with a very weak dependence on temperature, if at all, of the power law exponent as has been observed experimentally. At the lowest temperature investigated, jump motion is found to occur in both the translational and orientational degrees of freedom.
Chapter 3 studies how the binary mixture, introduced in the previous chapter, explores its underlying potential energy landscape. The study reveals correlations between the decoupling phenomena, observed almost universally in supercooled molecular liquids, and the manner of exploration of the energy landscape of the system. A significant deviation from the Debye model of rotational diffusion in the dynamics of ODOF is found to begin at a temperature at which the average inherent structure energy of the system starts falling as the temperature decreases. Further, the coupling between rotational diffusion and translational diffusion breaks down at a still lower temperature, where a change occurs in the temperature dependence of the average inherent structure energy.
Chapters 4-6 describe analytical and numerical approaches to solve kinetic models of glassy dynamics for various observables. The β process is modeled as a thermally activated event in a two-level system and the a process is described as a β relaxation mediated cooperative transition in a double-well. The model resembles a landscape picture, conceived by Stillinger [Science 267, 1935 (1995)], where the a process is assumed to involve a concerted series of the β processes, the latter being identified as elementary relaxations involving transitions between contiguous basins. For suitable choice of parameter values, the model could reproduce many of the experimentally observed features of anomalous heat capacity behavior during a temperature cycle through the glass transition as described in chapter 4. The overshoot of the heat capacity during the heating scan that marks the glass transition is found to be caused by a delayed energy relaxation. Chapter 5 shows that the model can also predict a frequency dependent heat capacity that reflects the two-step relaxation behavior. The high-frequency peak in the heat capacity spectra appears with considerably larger amplitude than the low-frequency peak, the latter being due to the a relaxation. The model, when simplified with a modified description of the a process that involves an irreversible escape from a metabasin, can be solved analytically for the relaxation time. This version of the model captures salient features of the structural relaxation in glassy systems as described in chapter 6.
In Part II, thermotropic liquid crystals are studied in molecular dynamics simulations using primarily the family of the Gay-Berne model systems. To start with, chapter 7 provides a brief introduction to thermotropic liquid crystals, especially from the perspective of the issues discussed in the following chapters. This chapter ends up with a detail description of the family of the Gay-Berne models.
Chapter 8 demonstrates that a model system for calamitic liquid crystal (comprising rod-like molecules) could capture the short-to-intermediate time power law decay in the OKE signal near the isotropic-nematic (I-N) phase transition as observed experimentally. The single-particle second rank orientational time correlation function (OTCF) for the model liquid crystalline system is also found to sustain a power law decay regime in the isotropic phase near the I-N transition. On transit across the I-N phase boundary, two power law decay regimes, separated by a plateau, emerge giving rise to a step-like feature in the single-particle second rank OTCF. When the time evolution of the rotational non-Gaussian parameter is monitored as a diagnostic of spatially heterogeneous dynamics, a dominant peak is found to appear following a shoulder at short times, signaling the growth of pseudonematic domains. These observations are compared with those relevant ones obtained for the supercooled binary mixture, as discussed in chapter 2, in the spirit of the analogy suggested recently by Fayer and coworkers [J. Chem. Phys. 118, 9303 (2003)].
In chapter 9, orientational dynamics across the I-N transition are investigated in a variety of model systems of thermotropic liquid crystals. A model discotic system that consists of disc-like molecules as well as a lattice system have been considered in the quest of a universal short-to-intermediate time power law decay in orientational relaxation, if any. A surprisingly general power law decay at short to intermediate times in orientational relaxation is observed in all these systems. While the power law decay of the OKE signal has been recently observed experimentally in calamitic systems near the I-N phase boundary and in the nematic phase by Fayer and coworkers [J. Chem. Phys. 116, 6339 (2002), J. Phys. Chem. B 109, 6514 (2005)], the prediction for the discotic system can be tested in experiments.
Chapter 10 presents the energy landscape view of phase transitions and slow dynamics in thermotropic liquid crystals by determining the inherent structures of a family of one-component Gay-Berne model systems. This study throws light on the interplay between the orientational order and the translational order in the mesophases the systems exhibit. The onset of the growth of the orientational order in the parent phase is found to induce a translational order, resulting in a smectic-like layer in the underlying inherent structures. The inherent structures, surprisingly, never seem to sustain orientational order alone if the parent nematic phase is sandwiched between the high-temperature isotropic phase and the low-temperature smectic phase. The Arrhenius temperature dependence of the orientational relaxation time breaks down near the I-N transition and this breakdown is found to occur at a temperature below which the system explores increasingly deeper potential energy minima. There exists a remarkable similarity in the manner of exploration of the potential energy landscape between the Gay-Berne systems studied here and the well known Kob-Andersen binary mixture reported previously [Nature, 393, 554 (1998)].
In search of a dynamical signature of the coupling between orientational order and translational order, anisotropic translational diffusion in the nematic phase has been investigated in the Gay-Berne model systems as described in chapter 11. The translational diffusion coefficient parallel to the director D// is found to first increase and then decrease as the temperature drops through the nematic phase. This reversal occurs where the smectic order parameter of the underlying inherent structures becomes significant for the first time. The non-monotonic temperature behavior of D// can thus be viewed from an energy landscape analysis as a dynamical signature of the coupling between orientational and translational order at the microscopic level. Such a view is likely to form the foundation of a theoretical framework to explain the anisotropic translation diffusion.
Chapter 12 investigates the validity of the Debye model of rotational diffusion near the I-N phase boundary with a molecular dynamics simulation study of a Gay-Berne model system for calamitic liquid crystals. The Debye model is found to break down near the I-N phase transition. The breakdown, unlike the one observed in supercooled molecular liquids where a jump diffusion model is often invoked, is attributed to the growth of orientational pair correlation. A mode-coupling theory analysis is provided in support of the explanation.
Chapter 13 presents a molecular dynamics study of a binary mixture of prolate ellipsoids of revolution with different aspect ratios interacting with each other through a generalized Gay-Berne potential. Such a study allows to investigate directly the aspect ratio dependence of the dynamical behavior.
In the concluding note, chapter 14 starts with a brief summary of the outcome of the thesis and ends up with suggestion of a few relevant problems that may prove worthwhile to be addressed in future.
3
Chakrabarti, Dwaipayan. "Slow Dynamics In Soft Condensed Matter : From Supercooled Liquids To Thermotropic Liquid Crystals." Thesis, Indian Institute of Science, 2006. http://hdl.handle.net/2005/292.
Full textAbstract:
This thesis, which contains fourteen chapters in two parts, presents theoretical and computer simulation studies of dynamics in supercooled liquids and thermotropic liquid crystals. These two apparently diverse physical systems are unified by a startling similarity in their complex slow dynamics. Part I consists of six chapters on supercooled liquids while Part II comprises seven chapters on thermotropic liquid crystals. The fourteenth chapter provides a concluding note.
Part I starts with an introduction to supercooled liquids given in chapter 1. This chapter discusses basic features of supercooled liquids and the glass transition and portrays some of the theoretical frameworks and formalisms that are widely recognized to have contributed to our present understanding.
Chapter 2 introduces a new model of binary mixture in order to study dynamics across the supercooled regime. The system consists of an equimolar mixture of the Lennard-Jones spheres and the Gay-Berne ellipsoids of revolution, and thus one of its components has orientational degrees of freedom (ODOF). A decoupling between trans-lational diffusion and rotational diffusion is found to occur below a temperature where the second rank orientational correlation time starts showing a steady deviation from the Arrhenius temperature behavior. At low temperatures, the optical Kerr effect (OKE) signal derived from the system shows a short-to-intermediate time power law decay with a very weak dependence on temperature, if at all, of the power law exponent as has been observed experimentally. At the lowest temperature investigated, jump motion is found to occur in both the translational and orientational degrees of freedom.
Chapter 3 studies how the binary mixture, introduced in the previous chapter, explores its underlying potential energy landscape. The study reveals correlations between the decoupling phenomena, observed almost universally in supercooled molecular liquids, and the manner of exploration of the energy landscape of the system. A significant deviation from the Debye model of rotational diffusion in the dynamics of ODOF is found to begin at a temperature at which the average inherent structure energy of the system starts falling as the temperature decreases. Further, the coupling between rotational diffusion and translational diffusion breaks down at a still lower temperature, where a change occurs in the temperature dependence of the average inherent structure energy.
Chapters 4-6 describe analytical and numerical approaches to solve kinetic models of glassy dynamics for various observables. The β process is modeled as a thermally activated event in a two-level system and the a process is described as a β relaxation mediated cooperative transition in a double-well. The model resembles a landscape picture, conceived by Stillinger [Science 267, 1935 (1995)], where the a process is assumed to involve a concerted series of the β processes, the latter being identified as elementary relaxations involving transitions between contiguous basins. For suitable choice of parameter values, the model could reproduce many of the experimentally observed features of anomalous heat capacity behavior during a temperature cycle through the glass transition as described in chapter 4. The overshoot of the heat capacity during the heating scan that marks the glass transition is found to be caused by a delayed energy relaxation. Chapter 5 shows that the model can also predict a frequency dependent heat capacity that reflects the two-step relaxation behavior. The high-frequency peak in the heat capacity spectra appears with considerably larger amplitude than the low-frequency peak, the latter being due to the a relaxation. The model, when simplified with a modified description of the a process that involves an irreversible escape from a metabasin, can be solved analytically for the relaxation time. This version of the model captures salient features of the structural relaxation in glassy systems as described in chapter 6.
In Part II, thermotropic liquid crystals are studied in molecular dynamics simulations using primarily the family of the Gay-Berne model systems. To start with, chapter 7 provides a brief introduction to thermotropic liquid crystals, especially from the perspective of the issues discussed in the following chapters. This chapter ends up with a detail description of the family of the Gay-Berne models.
Chapter 8 demonstrates that a model system for calamitic liquid crystal (comprising rod-like molecules) could capture the short-to-intermediate time power law decay in the OKE signal near the isotropic-nematic (I-N) phase transition as observed experimentally. The single-particle second rank orientational time correlation function (OTCF) for the model liquid crystalline system is also found to sustain a power law decay regime in the isotropic phase near the I-N transition. On transit across the I-N phase boundary, two power law decay regimes, separated by a plateau, emerge giving rise to a step-like feature in the single-particle second rank OTCF. When the time evolution of the rotational non-Gaussian parameter is monitored as a diagnostic of spatially heterogeneous dynamics, a dominant peak is found to appear following a shoulder at short times, signaling the growth of pseudonematic domains. These observations are compared with those relevant ones obtained for the supercooled binary mixture, as discussed in chapter 2, in the spirit of the analogy suggested recently by Fayer and coworkers [J. Chem. Phys. 118, 9303 (2003)].
In chapter 9, orientational dynamics across the I-N transition are investigated in a variety of model systems of thermotropic liquid crystals. A model discotic system that consists of disc-like molecules as well as a lattice system have been considered in the quest of a universal short-to-intermediate time power law decay in orientational relaxation, if any. A surprisingly general power law decay at short to intermediate times in orientational relaxation is observed in all these systems. While the power law decay of the OKE signal has been recently observed experimentally in calamitic systems near the I-N phase boundary and in the nematic phase by Fayer and coworkers [J. Chem. Phys. 116, 6339 (2002), J. Phys. Chem. B 109, 6514 (2005)], the prediction for the discotic system can be tested in experiments.
Chapter 10 presents the energy landscape view of phase transitions and slow dynamics in thermotropic liquid crystals by determining the inherent structures of a family of one-component Gay-Berne model systems. This study throws light on the interplay between the orientational order and the translational order in the mesophases the systems exhibit. The onset of the growth of the orientational order in the parent phase is found to induce a translational order, resulting in a smectic-like layer in the underlying inherent structures. The inherent structures, surprisingly, never seem to sustain orientational order alone if the parent nematic phase is sandwiched between the high-temperature isotropic phase and the low-temperature smectic phase. The Arrhenius temperature dependence of the orientational relaxation time breaks down near the I-N transition and this breakdown is found to occur at a temperature below which the system explores increasingly deeper potential energy minima. There exists a remarkable similarity in the manner of exploration of the potential energy landscape between the Gay-Berne systems studied here and the well known Kob-Andersen binary mixture reported previously [Nature, 393, 554 (1998)].
In search of a dynamical signature of the coupling between orientational order and translational order, anisotropic translational diffusion in the nematic phase has been investigated in the Gay-Berne model systems as described in chapter 11. The translational diffusion coefficient parallel to the director D// is found to first increase and then decrease as the temperature drops through the nematic phase. This reversal occurs where the smectic order parameter of the underlying inherent structures becomes significant for the first time. The non-monotonic temperature behavior of D// can thus be viewed from an energy landscape analysis as a dynamical signature of the coupling between orientational and translational order at the microscopic level. Such a view is likely to form the foundation of a theoretical framework to explain the anisotropic translation diffusion.
Chapter 12 investigates the validity of the Debye model of rotational diffusion near the I-N phase boundary with a molecular dynamics simulation study of a Gay-Berne model system for calamitic liquid crystals. The Debye model is found to break down near the I-N phase transition. The breakdown, unlike the one observed in supercooled molecular liquids where a jump diffusion model is often invoked, is attributed to the growth of orientational pair correlation. A mode-coupling theory analysis is provided in support of the explanation.
Chapter 13 presents a molecular dynamics study of a binary mixture of prolate ellipsoids of revolution with different aspect ratios interacting with each other through a generalized Gay-Berne potential. Such a study allows to investigate directly the aspect ratio dependence of the dynamical behavior.
In the concluding note, chapter 14 starts with a brief summary of the outcome of the thesis and ends up with suggestion of a few relevant problems that may prove worthwhile to be addressed in future.
4
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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Bastos, Pedro David Anastácio de. "Separation of azeotropic mixtures using high ionicity ionic liquids." Master's thesis, Faculdade de Ciências e Tecnologia, 2014. http://hdl.handle.net/10362/12208.
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Bribesh, Fathi. "Free surface films of binary liquid mixtures." Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/9810.
Full textAbstract:
Model-H is used to describe structures found in the phase separation in films of binary liquid mixture that have a surface that is free to deform and also may energetically prefer one of the components. The film rests on a solid smooth substrate that has no preference for any component. On the one hand the study focuses on static aspects by investigating steady states that are characterised by their concentration and film height profiles. A large variety of such states are systematically analysed by numerically constructing bifurcation diagrams in dependence of a number of control parameters. The numerical method used is based on minimising the free energy functional at given constraints within a finite element method for a variable domain shape. The structure of the bifurcation diagrams is related to the symmetry properties of the individual solutions on the various branches. On the other hand the full time dependent model-H is linearised about selected steady states, in particular, the laterally invariant, i.e.\ layered states. The resulting dispersion relations are discussed and related to the corresponding bifurcation points of the steady states. In general, the results do well agree and confirm each other. The described analysis is performed for a number of important cases whose comparison allows us to gain an advanced understanding of the system behaviour: We distinguish the critical and off-critical case that correspond to zero and non-zero mean concentration, respectively. In the critical case the investigation focuses on (i) flat films without surface bias, (ii) flat films with surface bias, (iii) height-modulated films without surface bias, and (iv) height-modulated films with surface bias. Each case is analysed for several mean film heights and (if applicable) energetic bias at the free surface using the lateral domain size as main control parameter. Linear stability analyses of layered films and symmetry considerations are used to understand the structures of the determined bifurcation diagrams. For off-critical mixtures our study is more restricted. There we consider height-modulated films without and with surface bias for several mean film heights and (if applicable) energetic bias employing the mean concentration as main control parameter.
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White, Garry. "A new adsorbent mixture for the collection of common ignitable liquid residue vapour." Thesis, Anglia Ruskin University, 2014. http://arro.anglia.ac.uk/700895/.
Full textAbstract:
United Kingdom fire investigators use ad hoc adsorbents to investigate the suspected use of ignitable liquids and their residues (ILR) at fire scenes. It was unknown whether these materials adsorb all ignitable liquid target compounds specified by ASTM methods, or if they interfered with such analysis and therefore prevented the positive identification of ignitable liquids. This research has ascertained that adsorbents such as clay based cat litter, montmorillonite, limestone, Tampax®, Tenalady®, talc; sand and the use of a squeegee tool cannot adsorb the full range of ASTM target compounds in common ignitable liquid residues by themselves. However, some can adsorb a limited range of target compounds. For example, cat litter can adsorb C3 and C4 alkylbenzenes and other molecules for the identification of petrol, but cannot adsorb heavy alkanes such as those found in diesel fuel. In contrast, limestone can adsorb heavy alkanes but not all aromatic target compounds present in petrol. This study has found that when limestone was mixed with Fuller’s Earth (10:1 w/w) that a range of common ignitable liquids and their associated target compounds could be adsorbed and identified. Furthermore, the instrumentation and separation methods used with an automated thermal desorption-gas chromatography-mass spectrometer (ATD-GC-MS) and Tenax TA® were improved and it is hoped that these would form a basis for a new standard method. Limestone and Fuller’s Earth as well as the limestone/Fuller’s Earth mixture were characterised with Fourier-Transform Infra-Red spectroscopy and X-ray Diffraction. The results showed that mixing the components together did not alter the chemical composition of the adsorbent mixture and that the major phases in the mixture were identified as calcite, quartz and palygorskite. The performance of the adsorbents was assessed using a combination of a standard ASTM method for analysis using GC-MS and an improved oven separation time of six to nine hours. The ATD method was improved for real fire debris samples by setting the split flow valves to 40 mL/min to minimise instrument overloading. The adsorbents were subjected to evaluation in the laboratory using blind tests and also a field blind test at a real fire scene. The laboratory analysis and fire scene evaluation revealed that the limestone/Fuller’s Earth mixture adsorbed all ignitable liquid target compounds from different ignitable liquids and as a result were identified from extracted ion chromatograms. This is the first reported use of this novel mixture as a universal adsorbent for common ignitable liquids.
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White, Garry. "A New Adsorbent Mixture for the Collection of Common Ignitable Liquid Residue Vapour." Thesis, Anglia Ruskin University, 2014. https://arro.anglia.ac.uk/id/eprint/700895/1/White_Thesis_2014.pdf.
Full textAbstract:
United Kingdom fire investigators use ad hoc adsorbents to investigate the suspected use of ignitable liquids and their residues (ILR) at fire scenes. It was unknown whether these materials adsorb all ignitable liquid target compounds specified by ASTM methods, or if they interfered with such analysis and therefore prevented the positive identification of ignitable liquids.
This research has ascertained that adsorbents such as clay based cat litter, montmorillonite, limestone, Tampax®, Tenalady®, talc; sand and the use of a squeegee tool cannot adsorb the full range of ASTM target compounds in common ignitable liquid residues by themselves. However, some can adsorb a limited range of target compounds. For example, cat litter can adsorb C3 and C4 alkylbenzenes and other molecules for the identification of petrol, but cannot adsorb heavy alkanes such as those found in diesel fuel. In contrast, limestone can adsorb heavy alkanes but not all aromatic target compounds present in petrol. This study has found that when limestone was mixed with Fuller’s Earth (10:1 w/w) that a range of common ignitable liquids and their associated target compounds could be adsorbed and identified. Furthermore, the instrumentation and separation methods used with an automated thermal desorption-gas chromatography-mass spectrometer (ATD-GC-MS) and Tenax TA® were improved and it is hoped that these would form a basis for a new standard method. Limestone and Fuller’s Earth as well as the limestone/Fuller’s Earth mixture were characterised with Fourier-Transform Infra-Red spectroscopy and X-ray Diffraction. The results showed that mixing the components together did not alter the chemical composition of the adsorbent mixture and that the major phases in the mixture were identified as calcite, quartz and palygorskite.
The performance of the adsorbents was assessed using a combination of a standard ASTM method for analysis using GC-MS and an improved oven separation time of six to nine hours. The ATD method was improved for real fire debris samples by setting the split flow valves to 40 mL/min to minimise instrument overloading. The adsorbents were subjected to evaluation in the laboratory using blind tests and also a field blind test at a real fire scene. The laboratory analysis and fire scene evaluation revealed that the limestone/Fuller’s Earth mixture adsorbed all ignitable liquid target compounds from different ignitable liquids and as a result were identified from extracted ion chromatograms. This is the first reported use of this novel mixture as a universal adsorbent for common ignitable liquids.
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Alahmad, Malik I. N. "Heat transfer in upward flowing two-phase gas-liquid mixtures : an experimental study of heat transfer in two-phase gas-liquid mixtures flowing upwards in a vertical tube with liquid phase being driven by a pump or air injection." Thesis, University of Bradford, 1987. http://hdl.handle.net/10454/3629.
Full textAbstract:
An experimental investigation has been carried out to study the heat transfer in a two-phase two-component mixture flowing upward inside a 1" double pipe heat exchanger. The heat transfer coefficient was measured using either air to lift the liquid (air-lift system) or a mechanical pump. The heat transfer coefficient results have been extensively studied and compared with other workers' results. An attempt was made to correlate the present heat transfer data in dimensionless correlations. Possible factors affecting the two-phase heat transfer coefficient have been studied with special attention being given to the fluid properties, particularly the liquid viscosity. Experiments were also carried out to investigate the effect of solid particles added to a liquid flow on the measured heat transfer coefficient. The present investigation was carried out using air as the gas-phase ranging from 2x 10-5 up to 80 x 10-5 m3/s. Liquids used were water and glycerol solutions with viscosity ranging from 0.75 up to 5.0 C. P. and flowrates between 4x 10-5 and 25 x 10-5 m3/s. Void fraction and pressure drop were also measured during the heat transfer process. Flow pattern in gas-liquid mixture was investigated in a perspex tube of identical dimensions to the heat exchanger tube.
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Turner, Robert Paul. "Pumping helium 3 in a helium mixture with a magnetic field : thermal boundary resistance between liquid helium mixtures and silver sinters." Thesis, Lancaster University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242945.
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Mohamed, Hmza Ashour. "Radiation Heat Transfer Analysis in Two-Phase Mixture Associated with Liquid Metal Reactor Accidents." University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1588950530150298.
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Zhang, Lin. "Photoelectrocatalytic CO2 conversion in ionic liquid/aqueous mixture solution studied by scanning electrochemical microscopy." Thesis, Sorbonne université, 2020. https://accesdistant.sorbonne-universite.fr/login?url=http://theses-intra.upmc.fr/modules/resources/download/theses/2020SORUS122.pdf.
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Cette thèse concerne l’étude de la réaction photoélectrochimique de réduction du CO2 (PEC CO2RR) sur le semi-conducteur de type p CuCo2O4 en abordant le rôle cocatalytique des RTIL à base d'imidazolium par microscopie photoélectrochimique à balayage (SPECM). Le CuCo2O4 a été étudié dans différents électrolytes supports, notamment une solution aqueuse, une solution de mélange binaire (25 vol.% [C2mim][BF4]/H2O et 25 vol.% [C4mim][BF4]/H2O) et des liquides ioniques pur pour explorer par SPECM le rôle des RTIL dans les performances des PEC. Un courant de photoréduction significativement amélioré sous l'éclairage UV-vis et visible est obtenu dans une solution à 25 vol.% [C2mim][BF4]/H2O. Seul le CO généré par la PEC CO2RR a été détecté sur une fibre optique à double sonde - ultra-microélectrode (OF-UME) développée au laboratoire et sur une électrolyse en volume sous illumination. La formation de CO à des potentiels plus positifs que la valeur thermodynamique est rapportée ici et il est clairement indiqué que la réduction directe du CO2 à la surface de l'électrode n'est pas le mécanisme. Un schéma de réaction possible pour la PEC CO2RR par l'intermédiaire de [C2mim]+ est proposé. Ainsi, nos résultats ont démontré pour la première fois le rôle cocatalytique de [C2mim]+ pour le PEC CO2RR. En outre, la CO2RR électrochimique a également été étudiée sur divers catalyseurs de métaux de transition, d'azote et de carbone (M–N–Cs). 25%Fe25%Co–N–C a montré la meilleure performance parmi les M–N–Cs étudiés. La présence de sites Co a fourni un effet synergique pour la génération de microcubes distribués riches en Fe, qui agissent comme des sites actifs dans la CO2RR électrochimiqueThis thesis studies photoelectrochemical CO2 reduction reaction (PEC CO2RR) on p-type semiconductor CuCo2O4 addressing the cocatalytic role of imidazolium based RTILs by scanning photoelectrochemical microscopy (SPECM). CuCo2O4 was studied in different solvent supporting electrolyte systems including: aqueous solution (0.1 M KHCO3 and 0.1 M Na2SO4), binary mixture solution (25 vol.% [C2mim][BF4]/H2O and 25 vol.% [C4mim][BF4]/H2O) and pure RTILs ([C2mim][BF4], [C4mim][BF4]) to explore by SPECM the role of RTILs in CuCo2O4 semiconductor PEC performance. Significantly enhanced photoreduction current under both UV-vis and visible light illumination is reported in 25 vol.% [C2mim][BF4]/H2O solution. Only CO generated from PEC CO2RR was detected using an in-situ detection method based on a home-made dual tip optical fiber-ultramicroelectrode (OF-UME) and from bulk electrolysis under illumination. The formation of CO at potentials more positive than the thermodynamic value clearly points out that direct CO2 reduction on the electrode surface is not the mechanism. A possible reaction scheme for the PEC CO2RR mediated by [C2mim]+ is proposed. Thus, our results have demonstrated for the first time the cocatalytic role of [C2mim]+ for the PEC CO2RR. In addition, electrochemical CO2RR has also been studied on various synthesized transition metal–nitrogen–carbon catalysts (M–N–Cs) by rotating disk electrode. 25%Fe25%Co–N–C exhibited the best performance among the studied M–N–Cs in this thesis. The presence of Co sites in that catalyst provided synergic effect for the generation of distributed Fe-rich microcubes, which act as active sites in electrochemical CO2RR
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Sans, Amanda Dzintra. "TRANSFERABLE STEP-POTENTIALS FOR HALOGENATED HYDROCARBONS AND MIXTURE PREDICTIONS FROM SPEADMD." University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1161032534.
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Guenoun, Patrick. "Instabilite des melanges de fluides : influence des forces de pesanteur et de mouillage." Paris 6, 1987. http://www.theses.fr/1987PA066127.
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Wang, Yunli. "Mass Spectrum Analysis of a Substance Sample Placed into Liquid Solution." Thesis, North Dakota State University, 2011. https://hdl.handle.net/10365/28881.
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Mass spectrometry is an analytical technique commonly used for determining elemental composition in a substance sample. For this purpose, the sample is placed into some liquid solution called liquid matrix. Unfortunately, the spectrum of the sample is not observable separate from that of the solution. Thus, it is desired to distinguish the sample spectrum. The analysis is usually based on the comparison of the mixed spectrum with the one of the sole solution. Introducing the missing information about the origin of observed spectrum peaks, the author obtains a classic set up for the Expectation-Maximization (EM) algorithm. The author proposed a mixture modeling the spectrum of the liquid solution as well as that of the sample. A bell-shaped probability mass function obtained by discretization of the univariate Gaussian probability density function was proposed or serving as a mixture component. The E- and M- steps were derived under the proposed model. The corresponding R program is written and tested on a small but challenging simulation example. Varying the number of mixture components for the liquid matrix and sample, the author found the correct model according to Bayesian Information Criterion. The initialization of the EM algorithm is a difficult standalone problem that was successfully resolved for this case. The author presents the findings and provides results from the simulation example as well as corresponding illustrations supporting the conclusions.
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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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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.
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.
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.
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.
Keywords:ternary mixture, falling film, diffusionequation, gas-phase control, liquid-phase control, selectivity,stability analysis, polymeric solution, evaporation, azeotrope,batch drying, continuous drying.
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Khalaf, Wadad Ghazi Dunia. "Effect of fluid viscosity and electrical conductivity on the ohmic heating rate of a solid-liquid mixture." The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1298902428.
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Moon, Go Young. "Synthesis and preparation of polysaccharide based membranes for the pervaporation separation of liquid mixture systems of industrial interest." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ60558.pdf.
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Shin, Younggy. "Liquid fuel behavior in the mixture preparation process during starting and warm-up in a spark ignition engine." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10919.
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Fujimoto, Hitoshi. "Flow fields of air-liquid droplet two-phase mixture and collision dynamics of a droplet on a surface." Kyoto University, 1995. http://hdl.handle.net/2433/160775.
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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものであるKyoto University (京都大学)
0048
新制・論文博士
博士(工学)
乙第8868号
論工博第2977号
新制||工||996(附属図書館)
UT51-95-D461
(主査)教授 八田 夏夫, 教授 鈴木 健二郎, 教授 赤松 映明
学位規則第4条第2項該当
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Lee, Joshua. "Experimental Analysis on the Effects of Superficial Liquid and Gas Velocities in the Removal of Hydrogen Sulfide From a Brine/Oil Mixture." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2137.
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Hydrogen Sulfide (H2S) is a harmful gas produced during petroleum extraction that leads to corrosion of drilling tools and pipelines. However, a H2S-scavenging liquid compound, when added to pipelines, interacts with liquids that absorbed H2S to create a non-corrosive bi-product. The interaction is associated with the mixing of gases and liquids. This thesis is a study on the effect of superficial gas and liquid velocities on the scavenger's efficiency. This study employs two experimental setups designed to simulate the mixing of gases and liquids within pipelines. A high pressure closed loop was designed and fabricated to determine the influence of gas, liquid velocities and liquid volume on the scavenger's efficiency. All experiments were conducted in this high pressure loop with a thousand feet of coiled tubing to simulate the horizontal section of the pipeline that runs along the ocean floor from the reservoir. This provided practical understanding to petroleum companies to make a better forecast of how the scavenger used in eliminating the H2S, is affected in the process of transporting the liquids and gases from the reservoir to the surface. For an adequate analysis, experiments on four liquid and four gas velocities ranging from 0.2m/s to 0.5m/s and 0.4m/s to 1.1m/s respectively were conducted. Results in this study indicated that increases in superficial gas velocity at low superficial liquid velocity decreases the scavenger efficiency while the opposite is seen at high superficial liquid velocity. In addition, the H2S mass absorption was not a function of liquid volume as would be seen in static reservoirs but more of a function of superficial liquid and gas velocities. With the scavenger interacting with the liquid absorbed H2S, it was expected that the efficiency would increase with the increase in volume but in this study this was not the case. The second experiment is a flow visualization loop which was designed to understand the flow regimes at high pressures. This was done by constructing four 25ft section hoses together with four foot long breaks for visualization. This provided a more fundamental study of the fluid's behavior inside the pipelines allowing for the creation of appropriate flow regime maps in air-water flow. A hundred experiments for two different pressures were conducted at the 25ft location. At high pressures, the flow regime map appeared to shift the transition zones.M.S.M.E.
Department of Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering MSME
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Khan, Nazmul. "Sparse Lagrangian MMC-LES Combustion Modelling of Liquid Sprays." Thesis, The University of Sydney, 2017. https://vuir.vu.edu.au/39312/.
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This thesis provides a detailed investigation of turbulent combustion modelling of liquid sprays. Modelling of liquid sprays is a challenging task due to the existence of a wide range of complexities in both liquid and gas phases and their interaction in the spray and combustion process. In such multiphase flow, there is a need to address all physical processes involved in each individual phase and jointly in the interaction of phases. In a multiphase flow, there are physical processes with respect to flow, energy, chemical reactions, and flame propagation. In the liquid phase, the physical processes include dispersion, evaporation, volatile formation and exchange of heat and mass transfer with the gas phase. In the gas phase, there is turbulent flow, mixing and chemical reactions. The model that is derived and validated in this thesis extends the existing capabilities of liquid spray modelling by introducing a novel model for heat and mass transfer in the liquid phase that is coupled with the gas phase simulation. The model is comprised of an Eulerian LES model for the gas phase mass, momentum, and reference mixture fraction, a Lagrangian fuel particle (LFP) model for the dispersion, evaporation, heat and mass transfer and volatile formation, and a second Lagrangian stochastic particle model based on a multiple mapping conditioning (MMC) to represent the turbulent reacting chemistry. This study simulates three experimental validation cases from the University of Sydney combustion lab: non-reacting kerosene, evaporating acetone and reacting acetone. The axial and radial profiles of droplets, gas velocity and gas phase temperature are in good agreement with experimental measurements. Importantly the results of the finite volume and Lagrangian stochastic particle schemes are shown to be consistent with each other.
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Pallewela, Gayani Nadeera. "Theory and simulation of liquids and liquid mixtures." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32495.
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Doctor of PhilosophyDepartment of Chemistry
Paul E. Smith
Kirkwood Buff (KB) theory is one of the most important theories of solutions. The theory can relate integrals over radial (pair) distribution functions (rdfs) in the grand canonical ensemble to common thermodynamic properties. An inversion of the KB theory has been proposed by Ben-Naim and this has led to the wide spread popularity of KB theory. The idea of the KB inversion procedure is to calculate KB integrals from available thermodynamic properties. The KB theory can be used to validate the force field (ff) parameters used in molecular dynamics simulations. We have tested a series of small molecule ff parameters using KB theory that consists of both atom centered partial atomic charges and extra charge sites. The results indicate that using extra charge sites, derived from QM calculations, does not necessarily provide a more accurate representation of condensed phase properties. A further study aimed at an ongoing project of deriving new biomolecular ff parameters based on KB theory, has developed ff parameters for esters in order to represent the ester conjugation of the phospholipid molecule. The models were further tested against experimental properties. Preferential solvation (PS) is an important concept of solution mixtures that can be described using KB theory. The difference between local composition and bulk composition in solution mixtures leads to the concept of PS. A generalized explanation based on local mole fractions was derived by Ben-Naim using KB theory. However, the original expressions have been modified over years. Here, we propose a new approach based on local volume fractions to explore PS in binary and ternary solution mixtures. Experimental and simulation data were used to examine different approaches to PS. A relationship between the rdf and the triplet distribution function can be obtained using the Kirkwood Superposition Approximation (KSA). A combination of Fluctuation Solution Theory and experimental rdfs are used to examine the KSA at a series of state points for pure water. The accuracy of several other approximate relationships between the pair and triplet correlation functions was also investigated and are in good agreement for regions of the phase diagram where the compressibility is small.
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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.QC 20110124
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Foster, Paul J. "Continuous Co-Separation by Liquid Absorption in Aqueous Cuprous Chloride (CuCl) and Magnesium Chloride (MgCl2) Solution." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1789.pdf.
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Liao, Chaqing. "Gas ejector modeling for design and analysis." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3206.
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Allan, Juliet N. McClatchey. "The prediction of the viscosity of liquids and liquid mixtures." Thesis, Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/11891.
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Paudel, Liladhar. "High Field 1H Nuclear Magnetic Resonance (NMR) Spectroscopy Based Metabolomics and Complex Mixture Analysis by Multidimensional NMR and Liquid Chromatography-Mass Spectrometry (LC-MS)." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1343403647.
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Kamonpatana, Pitiya. "MATHEMATICAL MODELING AND MICROBIOLOGICAL VERIFICATION OF OHMIC HEATING OF SOLID-LIQUID MIXURES IN CONTINUOUS FLOW OHMIC HEATER SYSTEMS." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1343490087.
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Himpsl, Andreas [Verfasser], Andreas [Akademischer Betreuer] Ulrich, Andreas [Gutachter] Ulrich, and Lothar [Gutachter] Oberauer. "Particle & Energy Dependence of the Near-Infrared to Vacuum-Ultraviolet Scintillation Ratio of a Liquid Argon-Xenon Mixture / Andreas Himpsl ; Gutachter: Andreas Ulrich, Lothar Oberauer ; Betreuer: Andreas Ulrich." München : Universitätsbibliothek der TU München, 2018. http://d-nb.info/116372873X/34.
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Waisberg, Jonatan Alexandre Hertel. "Elaboração de regra de mistura para estimativa de viscosidade dinâmica de mistura binária homogênea líquida." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-12122016-143336/.
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Neste trabalho, aplica-se uma regra de mistura desenvolvida pelo autor desta dissertação para estimar a viscosidade da mistura de duas substâncias líquidas a partir das viscosidades dessas puras, o que é usual a outros métodos. O aspecto de maior interesse é o caráter preditivo, ou seja, não requer a avaliação experimental de qualquer parâmetro da mistura para obtenção de estimativa da viscosidade da mesma. A formulação dessa regra é feita a partir de uma analogia e generalização da regra aplicada para misturas ideais, na qual a propriedade da mistura é uma ponderação das propriedades dos componentes puros, introduzindo um fator de ponderação alternativo à fração molar (ou mássica), que seria avaliado como função da composição da mistura. As constantes do modelo são obtidas a partir da ideia de uma composição local característica com considerações simplificadas de volume e área superficial das moléculas dos compostos na mistura. Os resultados obtidos apresentam desvios menores que os modelos preditivos mais conhecidos (UNIFAC-VISCO, ASOG-VISCO) para casos de mais de 30 misturas binárias verificados na literatura e ainda pode ser usado, de forma diferenciada, para tratar misturas aquosas e outras com comportamento análogo a estas.In this work, a mixing rule to estimate the viscosity of a mixture of two liquids from the viscosities of the pure liquids is presented. The most important feature of this mixing rule is its predictive character, i.e., it does not depend on the experimental determination of the mixture viscosity. This mixing rule is developed from a generalized rule applied for ideal mixtures, in which the property is averaged from those of the pure compounds by introducing an alternative weighting factor to replace the molar or mass fractions. This weighing factor is derived from a local composition reasoning, with simplifying considerations on the volume and surface area of the molecules that constitute the mixture. The developed mixing rule was compared to other predictive models (UNIFAC-VISCO, ASOG-VISCO) to predict the viscosity of liquid mixtures. The developed mixing rule resulted in a best prediction of the mixture viscosity, and could be applied (with minor changes introduced) to aqueous mixtures, which could not be adequately treated by other models.
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Lopez, Diego Ruben Schmeda. "Separação de CO2 em gases de combustão : aplicação de membranas e criogenia." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/24150.
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Este trabalho tem por objetivo avaliar a viabilidade técnica de processos de separação de gás carbônico em correntes de gases de combustão. Neste sentido, a separação por meio de membranas e por criogenia são avaliadas por meio de simulação de sistemas. As propostas envolvendo membranas avaliam arranjos de membranas em série, os quais são otimizados para condições de maior fluxo permeado e maior beneficio econômico. A corrente de alimentação é de 5 kmol/s e as respectivas frações molares de CO2 e N2 que compõem esta corrente são 0,15 e 0,85. Os resultados obtidos da otimização, para um arranjo de três membranas em série de polyimida de 9000 m² de área superficial, foram uma corrente de permeado de 443,1 mol/s de CO2 a 41,6%, correspondendo a aproximadamente 59% do CO2 da corrente de alimentação. Já com um arranjo de 6 membranas de 9000 m², onde a função objetivo é o maior lucro, foi selecionado o material kapton e a quantidade de CO2 separada é 161,12 mol/s, cuja concentração na mistura é de 79%, e a função objetivo tem um valor de 24.405,30 €/ano. Na outra parte do trabalho, propõe-se e avalia-se um ciclo para o aproveitamento da disponibilidade térmica na regasificação do gás natural líquido, para liquefação de CO2. Obtém-se como resultando em CO2 líquido com fração molar igual a 94%. Este processo consta de uma corrente proveniente da combustão completa de 1 mol/s de metano, contendo 1 mol/s de CO2 e 7,52 mol/s de N2. Esta corrente é comprimida e resfriada até atingir a pressão de 4000 kPa e 25 °C, posteriormente uma membrana enriquece a corrente de gases de combustão, que novamente é comprimida e resfriada até se obter a condensação e separação do CO2. Realiza-se o cálculo de equilíbrio líquido-vapor da mistura utilizando as equações de Peng-Robinson e a regra de mistura de Van der Waals no software VRTherm. A vazão molar do CO2 líquido obtida é de 0,3207 mol/s na concentração declarada. A intensidade energética do processo é de 1,135 kWh/kg de CO2 liquefeito.The objective of this work is to evaluate the technical feasibility of carbon dioxide separation processes of flue gases streams. In this way, separation processes due membrane and cryogenics are evaluated by system simulation. The systems using membranes evaluates setup of those membranes in series, these setups are optimized for the largest permeate molar flow and the largest economic profit. The feed stream is a 5 kmol/s CO2 – N2 mixture, with molar fraction of 0.15 and 0.85 respectively. The result obtained from the optimization for a setup of three polyimide membranes of 9000 m² is a permeate stream of 443.1 mol/s with CO2 at 41.6%, corresponding to aproximadely 59% of the CO2 contained in the feed stream. When a setup of six 9000 m² membranes is analyzed using an objective function that results in the largest profit, kapton was selected as the material for the membranes. The quantity of CO2 captured is 161.12 mol/s, at 79% of concentration in the mixture, and the objective function has a value of 24,405.30 €/year. The second part of this work, proposes and evaluates a cycle that takes the thermal availability of the regasification of liquid natural gas in advantage for CO2 liquefaction. The product of the cycle is liquid CO2, with a molar fraction of 0.94. The process is fed with a stream that comes from the stoichiometric combustion of 1 mol/s of methane, that stream is composed by 1 mol/s of CO2 and 7.52 mol/s of N2. The stream is then compressed up to the pressure of 4000 kPa and cooled down to 25 °C. After that a membrane concentrates the CO2 in one stream, which is again compressed and cooled down until the condensation of CO2 is achieved. Calculations of liquid – vapor are performed with the Peng- Robinson’s equations and the Van der Waals mixture rule using the software VRTherm. The molar flow rate of liquid CO2 obtained is of 0.3207 mol/s in the concentration mentioned before. The energy intensity of the process is of 1.135 kWh/kg of liquid CO2.
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Mensah-Brown, Henry. "Thermal conductivity of liquid mixtures." Thesis, Imperial College London, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362870.
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DI, LEO SIMONE. "SELECTIVE ASSEMBLY, PHASE TRANSITIONS AND MOLECULAR KINETICS OF DNA OLIGOMERS." Doctoral thesis, Università degli Studi di Milano, 2022. http://hdl.handle.net/2434/923222.
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In the last few years it has been shown that the spontaneous self-assembly process of short DNA and RNA duplexes into liquid crystal ordering is a likely potential route that led to the formation of first nucleic acids able to support biological activities. In particular, it has been experimentally demonstrated that liquid crystal domains behave as suitable micro-reactors to trigger polymerization between the stacked and not initially chemically linked short nucleic acids. Even paired mononucleotides at high enough concentration exhibit liquid crystal ordering, unveiling the crucial role of Watson-Crick selectivity and stacking attractive interactions among base pairs. In such a possible prebiotic context, DNA sequences with both random nucleobases sequence and length are likely to be formed. Surprisingly, it has been shown that even random DNA sequence of fixed length can support liquid crystal ordering at high concentration.
The aim of this PhD thesis is to extend the knowledge of DNA liquid crystals self-assembly in the following four directions.
First, I explored the selectivity of interaction in nucleic acids solutions of random-sequence DNA oligomers of different length L. The combination of experimental results and a suitable developed theoretical model revealed a not negligible percentage of perfect duplexes.
Second, I investigated the process that leads to the onset of the nematic liquid crystal phase in aqueous solutions of DNA duplexes. The combination of static light scattering experiments and computer simulations made possible the study of both aggregation and local ordering of DNA duplexes in the isotropic phase, where no positional order is developed, and in proximity of the isotropic-nematic phase boundary. This study gives an insight of the role on the development of local orientational order among DNA duplexes both far and in proximity of the isotropic-nematic phase boundary.
Third, I studied the diffusion of short DNA duplexes with attractive and repulsive interactions in the isotropic phase as a function of temperature. I found that the temperature dependence of diffusion coefficients reflects via an Arrhenius law the interduplex attractive interactions, whereas diffusion of repulsive duplexes is partially well described in terms of repulsive hard spheres.
Fourth, I investigated phase diagrams of mixtures of DNA single strands and duplexes with various polycations that show liquid-liquid phase separations. This phenomena leads to the onset of a concentrated but still liquid phase of polyelectrolytes, called coacervate, in a bulk phase where polyelectrolytes are diluted. The most surprising result I found, it is the insurgence of liquid crystals in coacervates with 12 nucleobases long random DNA oligomers and polylysine at different ionic strengths.
I believe that this PhD thesis adds important pieces to the self-assembly of nucleic acids puzzle, and in particular it shows how randomness of nucleic acids is not an impasse to both hybridization of defectless duplexes and liquid crystal ordering.
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Pascual, Marc. "Etude hydrodynamique des mélanges binaires thermosensibles." Thesis, Université Paris sciences et lettres, 2020. http://www.theses.fr/2020UPSLS009.
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La nanofluidique marque l'émergence de nouvelles technologies prometteuses pour la production d'énergies bleues. Ces énergies renouvelables à faible impact environnemental exploitent l'entropie de mélange de l'eau douce et l'eau salée, par exemple à l'estuaire d'un fleuve, pour générer de l'électricité. La diffusio-osmose (écoulement associé au déplacement diffusiophorétique) est un candidat sérieux pour la génération de courants électriques. Ce phénomène prend naissance à l'intérieur même des nanopores d’une membrane, et son intensité est directement liée à la charge de surface du matériau. Les mélanges binaires thermosensibles eau-liquide ionique sont une alternative aux fleuves et océans pour générer un gradient salin. L'état monophasique ou biphasique du mélange est contrôlé par la température; dans le cas présent la nature LCST du fluide induit une démixtion par chauffage.Nos travaux se concentrent sur la séparation de phase du mélange en cavité microfluidique, où nous montrons qu'un gradient de confinement ou de température sont une aide précieuse pour isoler sélectivement les deux phases. Nous mesurons également l'intensité des courants diffusio-osmotiques avec ces solutions de liquides ioniques dans des nanopores uniques et des membranes multiporesNanofluidics marks the emergence of promising new technologies for the production of blue energies. These renewable energies with low environmental impact harness the entropy of mixing of fresh and salt water, for example at the estuary of a river, to generate electricity. Diffusio-osmosis (which flow is associated with diffusiophoretic displacement) is a serious candidate for the generation of electric currents. This phenomenon stems from osmotic effects inside the nanopores of the membrane and its intensity is directly linked to the surface charge of the material. Waterionic liquid thermoresponsive binary mixtures are an alternative to rivers and oceans to generate a salt gradient. The monophasic or biphasic state of the mixture is controlled by temperature; in the present case the LCST nature of the fluid induces a demixing by heating. Our work focuses on the phase separation of the mixture in a microfluidic cavity, where we show that a confinement or temperature gradient is a precious help to selectively isolate the two phases. We also measure the intensity of diffusio-osmotic currents with these solutions of ionic liquids in single nanopores and multi-pore membranes
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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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Belghazi, Mourad. "Condensation d'un fluide pur et de mélanges zéotropes à l'extérieur d'un faisceau de tubes à surface améliorée." Université Joseph Fourier (Grenoble), 2001. http://www.theses.fr/2001GRE10055.
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Stevar, M. S. P. "Dissolution dynamics of liquid/liquid binary mixtures in porous media." Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/349974/.
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In this project has been undertaken an experimental study aimed at understanding the dissolution dynamics of binary mixtures within porous media. The porous medium can be roughly represented as a network of capillary tubes. This allowed for the initial research to be focused on understanding the dissolution dynamics of binary mixtures (i.e. glycerol/water, soybean oil/hexane, and isobutyric acid/water) within single capillary tubes. Further, the dissolution process was investigated within a 2D micromodel built as a network of capillary tubes. In the experiments with the capillary tubes, the dissolution (i.e. the interfacial mass transfer) could be isolated from the hydrodynamic motion while using glycerol/water and soybean oil/hexane binary mixtures. Despite the fact that these are fully miscible liquids, the interface could be observed for rather long time periods. In particular, two phase boundaries were observed moving from the ends into the middle section of the capillary tube with the speeds v∼D^1/3t^-2/3d^2(D, t and d are the coefficient of diffusion, time and diameter of the capillary tube, respectively). The boundaries slowly smeared but their smearing occurred very slow in comparison to their motion. The motion of the phase boundaries cannot be explained by the dependency of the diffusion coefficient on concentration, and could possibly be explained by the effect of barodiffusion. In addition, these solute/solvent boundaries were endowed with non-zero interfacial tension. This experimental study also revealed that the solvent penetration into the micromodel is diffusion-dominated for completely miscible binary mixtures. This is however non-Fickian diffusion with the dissolution rate dV/dt∼D^1/3t^-0.4 for almost the entire duration of the experiment (V is the volume occupied by the solvent, D is the diffusion coefficient and t is time). For the IBA/water mixture the experiments performed at undercritical temperatures revealed that the diffusive mass transport was negligible despite the mixture being out of its thermodynamic equilibrium. Despite a seeming simplicity of the experiments, to the author’s best knowledge, there is no theory that could correctly describe the observed diffusional penetration of a solvent into a solute-filled capillary tube and hence, into a more complex porous volume.
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Al-Anzi, Hamdan. "Mass transfer characteristics of two-aqueous-phase liquid-liquid mixtures." Thesis, Aston University, 1998. http://publications.aston.ac.uk/9604/.
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Mass transfer rates were studied using the falling drop method. Cibacron Blue 3 GA dye was the transferring solute from the salt phase to the PEG phase. Measurements were undertaken for several concentrations of the dye and the phase-forming solutes and with a range of different drop sizes, e.g. 2.8, 3.0 and 3.7 mm. The dye was observed to be present in the salt phase as finely dispersed solids but a model confirmed that the mass transfer process could still be described by an equation based upon the Whitman two-film model. The overall mass transfer coefficient increased with increasing concentration of the dye. The apparent mass transfer coefficient ranged from 1 x 10-5 to 2 x 10 -4 m/s. Further experiments suggested that mass transfer was enhanced at high concentration by several mechanisms. The dye was found to change the equilibrium composition of the two phases, leading to transfer of salt between the drop and continuous phases. It also lowered the interfacial tension (i.e. from 1.43 x 10-4 N/m for 0.01% w/w dye concentration to 1.07 x 10-4 N/m for 0.2% w/w dye concentration) between the two phases, which could have caused interfacial instabilities (Marangoni effects). The largest drops were deformable, which resulted in a significant increase in the mass transfer rate. Drop size distribution and Sauter mean drop diameter were studied on-line in a 1 litre agitated vessel using a laser diffraction technique. The effects of phase concentration, dispersed phase hold-up and impeller speed were investigated for the salt-PEG system. An increase in agitation speed in the range 300 rpm to 1000 rpm caused a decrease in mean drop diameter, e.g. from 50 m to 15 m. A characteristic bimodal drop size distribution was established within a very short time. An increase in agitation rate caused a shift of the larger drop size peak to a smaller size.
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chang, Hsiu-Ying, and 張綉英. "A Study on Liquid-Liquid Equilibria of Acrylic Monomer + Sec-Alcohol + Water Mixture System." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/69961559858678768265.
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碩士明新科技大學
化學工程研究所
95
Liquid-liquid equilibrium (LLE) data for the systems water + 2-propanol + methyl methacrylate, butyl methacrylate or isobutyl methacrylate, water + 2-butanol + methyl methacrylate, butyl methacrylate or isobutyl methacrylate, and water + 2-pentanol + butyl methacrylate and isobutyl methacrylate were determined at atmospheric pressure over temperatures of 288.15 K and 318.15 K. The reliability of the experimental tie-line data was determined through the Othmer-Tobias and Bachman plots. The new LLE data were also compared with the values correlated by the NRTL and UNIQUAC models. Good quantitative agreement was obtained with these models. Overall average deviation values are below 0.0080.
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SHILPA. "AUTOMATED SYSTEM FOR BOTTLE FILLING OF LIQUID MIXTURE USING PLC." Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14757.
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ABSTRACT
Automating the routine tasks in the industries increases the productivity and reduces the
probability of error in the system. Traditional methods of bottle filling involved placing
bottles manually and filling it. This method is time consuming and expensive. This task
needs separate manpower and thus is prone to errors. To automate the control of liquids and
mixing two different liquids in defined proportion and finally filling the generated mixer in
the bottles automatically and also to reduce human intervention, a PLC based automated
bottle filling system is designed. In this bottle filling system, liquids kept in two different
reservoir tanks are mixed in a third tank (overhead tank) and mixed liquid is filled in
bottles, placed on the conveyor belt. In such process there is no need of labor so there is no
human error. Without human error, the quality of product is better and the cost of
production would definitely decrease. The implemented automated system has many
features such as high level and low level indicators, emergency alarm creations for warning
the operator etc. The ON/OFF controls of motors for controlling the liquid level, conveyor
belt motor, operation and control of solenoid valve for filling the bottles etc are carried out
by PLC programming through ladder logic.
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曾宗益. "A study on the Liquid-Liquid Equilibria of Acrylic Monomer + n-alkanol + Water Mixture Systems." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/11504831496278608419.
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碩士明新科技大學
化學工程研究所
96
Abstract Alcohols are widely used as co-emulsifiers in the emulsion polymerization of many acrylic resins. It is well known that the influences of the mutual solubility of co-emulsifiers and monomers in water on the results of emulsion polymerization are very large, including the critical micelle concentration (CMC) of emulsifiers, the emulsified nucleation mechanism, and the reaction kinetics, etc. In this thesis, we are interested in investigating the fundamental solubility properties of those co-emulsifiers and methacrylic monomers in water for the acrylic emulsion polymerization application. Liquid-liquid equilibrium (LLE) data for the systems water + (1-hexanol or 1-octanol) + methyl methacrylate, + butyl methacrylate, or + isobutyl methacrylate were determined at atmospheric pressure over temperatures of 288.15 K and 318.15 K. From these new LLE data, we can find that very small amounts of the organic compounds were found in the aqueous phase, while water dissolved appreciably in the organic-rich phase. The reliability of the experimental tie-line data was determined through the Othmer-Tobias and Bachman plots. The experimental data were also compared with the values correlated by the NRTL and UNIQUAC models. Good quantitative agreement was obtained with these models. In general, the average deviations from the UNIQUAC model are slightly smaller than those from the NRTL model.
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Lee, Tsai-Feng, and 李茞玢. "Study of Heat Capacity of Binary Liquid Mixture with Polymer." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/86266443702947417994.
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碩士國立東華大學
應用物理研究所
96
Our goal is to study the change of a binary mixture system within polymers. In experiments, we measure the heat capacity of 2,6-lutidine with water by TAM, and the critical exponent of heat capacity is found to be 0.09. When we put the PAA into the mixed solvent, and a becomes very small. In computer simulations, we find out that the critical exponent nu of Ising systems with polymers become 0.44, independent of the polymer concentration and polymer length. From the simulation results we find that in Ising systems with polymers is smaller than that in pure Ising system. We also find that the critical temperature increases linearly with polymer concentration.
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JIAN, ZHI-HONG, and 簡志宏. "Unsteady binary liquid mixture natural convection in a square enclosure." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/64895771807329440877.
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Lin, Ruo-Yu, and 林若彧. "Physical and Device Characteristics of a Binary Liquid-Crystal Mixture." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/24855481456611251197.
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碩士中原大學
物理研究所
98
This research focuses on physical properties of binary mixtures containing a major positive liquid crystal and a minor negative one. The physical characteristics investigated include the phase-transition temperature, birefringence, dielectric anisotropy, and the rotational viscosity. In addition, the response times of the devices made of various mixtures with distinct content ratios have also been studied. Many material and device properties of the binary mixture can be tunable by changing the compositional ratio of the two liquid-crystal components. The experimental results show that the phase-transition temperatures are altered when the major liquid crystal is blended with the negative liquid crystal. The changes include the decrease in the melting point, increase in the clearing point, and, in turn, the wider range of the mesophase. The birefringence of the binary liquid crystal decreases with increasing concentration of the negative-liquid-crystal component because the birefringence of the negative dielectric anisotropy is less than that of the positive one. The physical properties of the binary substance, such as the dielectric anisotropy and rotational viscosity, change at various temperatures. Furthermore, the response time of the blend rises exponentially with the increase in concentration of the liquid crystal with negative dielectric anisotropy.
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許敬揚. "A Study on Liquid-Liquid Equilibria of Acrylic Monomer + 2-Ethyl-1-hexanol + Water Mixture System." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/18118957468480591367.
Full textAbstract:
碩士明新科技大學
化學工程研究所
97
In this thesis, we have measured liquid-liquid equilibrium (LLE) data for the systems water + 2-ethyl-1-hexanol + methacrylic acid, + methyl methacrylate, + ethyl methacrylate, or + isobutyl methacrylate were determined at atmospheric pressure over temperatures of 288.15 K and 318.15 K. In the methacrylic acid mixture system, since water + 2-ethyl-1-hexanol is the only liquid pair that is partially miscible, the ternary system water + 2-ethyl-1-hexanol + methacrylic acid behaves as Type I of LLE. On the other hand, since 2-ethyl-1-hexanol + methacrylate is the only liquid pair that is completely miscible and the two liquid pairs (water + 2-ethyl-1-hexanol) and (water + methacrylate) are partially miscible. All the other investigated ternary systems behave as Type II of LLE. From these new LLE data, the reliability of the experimental tie-line data was determined through the Othmer-Tobia and Bachman plots. Finally, the experimental data were also compared with the values correlated by the NRTL and UNIQUAC models. Good quantitative agreement was obtained with these models.
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Lau, Cheuk-Wah, and 劉卓華. "Studies of Second Harmonic Generation in Polymer-Liquid Crystal Mixture Films." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/87451765569026382811.
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Wei-Yuan, Lai, and 賴威遠. "Rheological research of two phase mixture of liquid crystal and polymer." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/69386843490681416313.
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碩士東海大學
化學工程學系
87
The rheological behavior of the mixture of polymer, poly butyl acrylate (PBA) and cholesteric liquid crystal, cholesteryl oleyl carbonate (ChOC) was investigated. We used rotational rheometer RDAⅡ to do dynamic strain/frequency sweep tests, transient step rate tests, and steady rate sweep tests. In dynamic frequency sweep tests, dynamic storage modulus G'' increases with PBA concentration. But when PBA concentration is over 80%, G'' decreases. This tells us that suspensions have solid elastic behavior. Several theoretical equations predict that viscosity increase when phase volume increase. But in our steady rate sweep tests, it only established in low phase volume and low shear rate for ChOC/PBA mixtures in our case. And for PBA/ChOC mixtures, shear viscosity was overpredicted in certain concentration. We also got a conclusion that theoretical equations that predict viscosity can''t handle the case which droplets deformed.
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Chen, Feng min, and 陳逢民. "Physical properties of binary mixture of the ionic liquid in solvents." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/21380513182878653018.
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碩士明志科技大學
化學工程研究所
100
This study reports on the synthesis and the physical properties of ionic liquid of 1-isoalkyl-3-methylimidazolium bromide [i-Cnmim][Br], (n＝3,4,5)。The values of density, refractive index , viscosity and conductivity at temperature range from 298.15 to 338.15 K were measured and reported for the 1-isoalkyl-3-methylimidazolium bromide ionic liquid。Empirical correlations were proposed to represent the present experimental data。The density, refractive index and viscosity values decrease with increasing temperature。The density and refractive index values decrease with the increases in the length of the alkyl chain in the imidazolium cation。The viscosity value increase with increasing in the length of the alkyl chain in the imidazolium cation 。The conductivity values increase with increasing temperature。 In the study，densities , refractive index and viscosity of the 1-isoalkyl-3-methylimidazolium bromide, in water ,methanol , ethanol ,1-propanol and 1-butanol at a temperature range from 298.15 to 338.15 K and atmospheric pressure were measured over the whole composition range。Excess molar volumes , refractive index deviations and viscosity deviations for the binary systems were calculated 。These results were fitted to a Redlich-kister equation to determine the fitting parameters and the root mean square deviations。
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ZHANG, WEN-RUI, and 張文瑞. "Unsteady thermosolutal convection in a shallow enclosure of liquid water mixture." Thesis, 1991. http://ndltd.ncl.edu.tw/handle/72551896776120383232.
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