Dissertations / Theses on the topic 'Liquids Measurement'
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Ge, R. "Measurement of Physicochemical Properties of Ionic Liquids." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527700.
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Combs, Roger J. "Gaseous diffusion in liquids." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/76484.
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Diffusivity of nonreactive gases in liquids provides a means of interpreting structure in the liquid state. Structural models of the liquid state include Hildebrand's condensed gas model and Eyring's pseudo-lattice model. The former model predicts a linear dependence of diffusivity with temperature while the latter model predicts linear dependence of log(D) versus 1/T. The limited temperature dependent diffusivity data to date with a typical precision of ± 5% do not permit distinguishing which temperature dependence is more linear. However, the present investigation shows that diffusivities of one gas solute in two nonpolar liquids indirectly supports a linear diffusivity temperature dependence by a Graham's law like relation. At a fixed temperature this relation equates relative diffusivities to the square root of the inverse molecular weights of the respective liquids.
Diffusion of gases into nonpolar liquids have previously been measured by two techniques: (1) a pseudo-steady state technique developed by Hildebrand with diffusion through multiple capillaries and (2) a method by Walkley with diffusion through an open tube. Each of these methods requires prior knowledge of solubility of the gas in the liquid. An apparatus is constructed which combines these methods into a single experiment. Simultaneous solution of the two equations which describe the combined experiment yields both the solubility and diffusion coefficient. Diffusivities and solubilities of nitrogen, argon and oxygen into liquids of carbon tetrachloride and benzene as well as oxygen into water have been studied. The results compare favorably with the Literature.
The diffusion cell for this technique consists of a capillary disk, which is flooded with liquid. Gas is admitted into the space over the open solvent. With temperature and pressure constant, volume uptake of the gas in the solvent is monitored. Time-volume uptake data is evaluated by the two diffusion equations. Although the experiment is conceptually easy, a small gas volume change over a prolonged period of time poses problems in data collection and experiment control. The data collection and control is simplified by dedicating a Microcomputer Interfaced Data Acquisition System (MIDAS) to the experiment.Ph. D.
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TRINDADE, IRIS DA SILVA. "PROPOSITION OF METROLOGICAL CONTROL FOR MEASUREMENT OF CRYOGENIC LIQUIDS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=4405@1.
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INSTITUTO NACIONAL DE METROLOGIA, QUALIDADE E TECNOLOGIALíquidos criogênicos são amplamente empregados em diversos segmentos da atuação humana, destacando-se a Medicina, Engenharia Genética, setor industrial e no desenvolvimento cientifico. Sendo assim, efetuar o controle metrológico sobre os dispositivos e sistemas utilizados na comercialização de tais materiais é fundamental. Nesta dissertação propomos a implementação do controle metrológico neste segmento como forma de estabelecer confiabilidade e garantir trocas cada vez mais justas, sem prejuízos as partes envolvidas. Para tal, a estrutura legal é amparada pela regulamentação vigente no âmbito brasileiro, a qual é abordada e confrontada com as diretrizes internacionais. Os diferentes sistemas de medição atualmente adotados são abordados, com o intuito de julgar a adequação dos mesmos e estabelecer requisitos mínimos. Diante da inexistência de uma regulamentação ampla, capaz de agregar aspectos não só inerentes às boas práticas, mas que contemplem a realidade do mercado nacional, são estabelecidas proposições e diretrizes a serem seguidas na implementação e efetivação do controle metrológico.
Cryogenic liquids are widely employed in several fields of human activity,such as in Medicine, Genetics Engineering, the industrial sector and for the scientific development. This way, applying the metrological controls in devices and systems used for the commercialization of cryogenic liquids is essential. In this dissertation we proposed the implementation of the metrological controls in this area, objectifying to establish the reliability and the guarantee of fair trade,without damages for the involved parts. Thus, the legal structure is supported by the valid regulamentation in the Brazilian case, that is mentioned and faced against international policies. The different measurement systems adopted nowadays are approached, for judging their adequacy and establishing minimum requests. Considering that there is not a broad regulamentaion, capable of aggregate aspects of the good practice and to heed the national reality, proposals and guidelines are presented for reaching the implementation of effective metrological controls.
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Taylor, Donald Fulton. "Measurement of binary phase equilibria and ternary/quaternary gas antisolvent (GAS) system measurement and analysis." Thesis, Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-07112004-194307/unrestricted/taylor%5Fonald%5Ff%5F200407%5FMS.pdf.
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Thesis (M.S.)--School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2005. Directed by Charles Eckert.Charles Eckert, Committee Chair ; Amyn Teja, Committee Member ; Pete Ludovice, Committee Member. Includes bibliographical references.
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Ogunlade, Olumide. "Measurement of the microwave dielectric properties of liquids using waveguide structures." Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556018.
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A variety of waveguide structures have been analysed for the measurement of the complex dielectric permittivity of liquids. Mode matching techniques are im- plemented to solve the forward problem of computing the scattering parameters for a sample of known permittivity filling a rectangular metal waveguide. Three different sample geometries are used. In the first, the liquid and the sample holder completely fill the waveguide cross section. As a result, only the dominant waveguide modes are matched across the discontinuity interface and an exact an- alytical relation between the S parameters and permittivity can be written. The second and third configurations are concentric cylinders and rectangles respec- tively, partially filling a metal waveguide, hence higher order modes are taken into account in the formulation. For the partially filled rectangular sample, a generalised scattering matrix method to obtain the overall scattering parameters due to the several discontinuity regions. Iterative methods are then introduced to solve the inverse problem of recover- ing the unknown permittivity from simulated or measured scattering parameters. For the partially filled waveguides, because an exact analytical relation does not exist, objective( error) functions are defined and minimized. The partially filled rectangular sample case is extended to obtain the resonant frequency and qual- ity factor of a dielectric loaded resonant cavity, and the results compared to the approximation normally used for the cavity perturbation technique. Finally, a rectangular dielectric waveguide method for liquid measurements was developed. This method has a treatment similar to the well known free space tech- niques. It has a distinct advantage of relaxing the strict requirements of sample dimension associated with metal waveguides, especially at higher frequencies.
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Chen, Zhuo. "Automated measurement of the kinetics of chemical reactions in ionic liquids." Thesis, University of Sheffield, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434490.
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Kim, Yoen Hee Scherz Julie. "Inconsistency in the line spread test as an objective measurement of thickened liquids." Diss., A link to full text of this thesis in SOAR, 2007. http://soar.wichita.edu/dspace/handle/10057/1142.
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Thesis (M.A.)--Wichita State University, College of Health Professions, Dept. of Communication Sciences and Disorders."May 2007." Title from PDF title page (viewed on Dec. 26, 2007). Thesis adviser: Julie Scherz. Includes bibliographical references (46-51 leaves).
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Barrow, M. "Rheometrical techniques for the measurement of the uniaxial extensional viscosity of mobile liquids." Thesis, Swansea University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636046.
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This thesis describes work involving the measurement of the uniaxial extensional viscosity of mobile elastic liquids using three methods namely: the falling mass technique of Matta and Tytus (1990), the rotating drum technique of Jones et al (1986) and the tube arrest (T-A) experiment of Chesterman (1952). The work assesses the application of each of these methods to liquids of varying shear viscosity and elasticity. The falling mass experiment is found to be insensitive to the stretching forces generated in low viscosity liquids, but adequate for highly elastic liquids. The development of elastic instabilities is observed to occur above critical values of strain and extension rate. Using video imaging the rotating drum technique has been revised and improved theory developed. The technique is found suited to highly elastic, high viscosity liquids but cannot repeatably produce Newtonian filaments: it is shown to produce perfect uniaxial extension at moderate extensional rates. Fibrillation is observed involving an instability restricted to a single contact point. A study of the origins of the stretching force reveals that the influence of the flow instability on the stress generated in the filament is markedly reduced. The modified T-A experiment is used to produce high velocity liquid filaments, formed from collapse of a bubble beneath a liquid's surface: it facilitates the study of low viscosity, low elasticity liquids, at high extensional rates, accompanied by large strains. Studies of aqueous solutions of high molecular weight polyacrylamide show that at high rates, a marked deceleration of the filament occurs due to a significant increase in resistance to extensional flow. The relative contributions of the inertial and extensional flow components are assessed by volumetric analysis procedures. For polymer enhanced multi-grade motor oils, it was shown that the filaments contain a significant extensional component, with an upper limit of extensional rate far in excess of that achievable in commercial rheometers.
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Figueroa, Anna Ajaro-Oyara. "Measurement of pressure-saturation hysteresis curves for three liquids in Vinton fine sand." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282816.
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Measurement of water is important in soil since this is the medium in which soil activity takes place. Pressure-saturation curves show the extent of liquid retention in the soil porous medium at different tensions during drainage and sorption (hysteresis). Measurement of soil moisture in the laboratory is time-consuming, labor-intensive and expensive. In this study, three methods for measuring pressure-saturation curves were employed, Hanging Water Column (HWC), Differential Pressure Transducer-Imbibition, and Differential Pressure Transducer-Natural. The standard HWC is compared to the other two methods which employ external manometer pressure and differential pressure transducers. Hysteresis pressure-saturation curves were determined for three liquids (water, 50% ethanol and 100% ethanol), in a homogeneous Vinton fine sand. Data was fit to the van Genuchten and Brooks Corey models and liquid capillary numbers are compared. Prediction of desorption pressure-saturation curves from water curves using relative surface tension ratios is discussed and prediction of sorption curves using relative A parameters for the drying and wetting curves. Scanning curves were scaled from the main drying and wetting curves. The capillary number-pore water velocity combination function could be another useful relationship for pressure-saturation curves. Overall, the differential pressure transducer methods were found superior to the HWC because time consumption was reduced by more than 50% yet the results obtained were of comparable accuracy. Pressure-saturation curves for other liquids may be predicted by scaling pressure and van Genuchten alpha parameter with relative surface tension ratios. Hence, hysteresis curves can be obtained faster and the main disadvantages of time-consumption, labor and cost are eliminated. In addition, handling of hazardous liquids in the laboratory is minimized which is important because understanding retention of hazardous chemicals in soil is a prerequisite to achieving remediation of residual contamination. Functional relationship between the residual nonwetting phase and the capillary number or viscosity to surface tension ratio is briefly discussed.
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Peters, Christine Jutta [Verfasser], André [Akademischer Betreuer] Bardow, and Jean-Babtiste [Akademischer Betreuer] Salmon. "Measurement of multicomponent diffusion in liquids using raman microspectroscopy and microfluidics / Christine Jutta Peters ; André Bardow, Jean-Babtiste Salmon." Aachen : Universitätsbibliothek der RWTH Aachen, 2020. http://d-nb.info/1221808613/34.
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Rharbaoui, Brahim. "Contribution à l'étude de la mesure simultanée de la conductivité et de la diffusivité thermiques par la méthode du fil chaud." Angers, 1994. http://www.theses.fr/1994ANGE0007.
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Nous avons mis au point un dispositif expérimental pour la mesure de la conductivité et de la diffusivité thermiques des fluides par la méthode du fil chaud. L'ensemble de l'appareillage comporte une cellule a fil chaud, un pont de mesure et des matériels électroniques de traitement du signal et d'enregistrement par micro-ordinateur. L'ensemble des tests effectués avec cet appareillage nous a permis d'obtenir des mesures de la conductivité et de la diffusivité thermiques en bon accord avec les données existantes. Le matériel électronique utilise permet d'obtenir aisément les courbes expérimentales avec une précision satisfaisante. Le traitement des données a été effectué par le logiciel le superscope. La seconde partie de cette étude porte sur l'analyse des divers phénomènes physiques qui ont lieu dans la cellule d'étude et qui peuvent engendrer des erreurs dans la détermination expérimentale de la conductivité et la diffusivité thermiques. Nous avons montre que les corrections les plus importantes sont celles dues à la capacité thermique du fil et a la détermination des caractéristiques géométriques de celui-ci, ainsi qu'à l'influence des dimensions de la cellule de mesure. Les corrections dues aux pertes radiatives, a l'effet Knudsen, a la dissipation visqueuse, sont relativement négligeables par rapport aux corrections précédentes.
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Januš, Petr. "Nejistoty měření dynamické viskozity." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219808.
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The thesis is deal with measuring the temperature dependence of dynamic viscosity and the calculation of measurement uncertainties. The thesis writes up the physical nature of viscosity and rheological properties. Next it is write up an overview of possible methods for measuring viscosity of liquids and overview of methods for measuring the density of liquids. An important chapter is the statistical evaluation of measured data represented mainly measurement uncertainties. In the practical part of the work is done workplace for measure the temperature dependence of dynamic viscosity. It is used two methods of measuring viscosity of liquids and two samples of liquids. Finally is done statistical evaluations of measurement. Based on the calculated measurement uncertainty measurement methods are compared.
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Scoppola, Ernesto. "Solvent extraction : a study of the liquid/liquid interface with ligands combining x-ray and neutron reflectivity measurements." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS203/document.
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Dans le cadre du retraitement des déchets nucléaires et du recyclage de métaux critiques, l'extraction par solvant est l'une des technologies les plus utilisées. L'interface liquide entre deux fluides non miscibles est considérée comme une région où de multiples phénomènes physiques et chimiques sont à prendre en compte et peuvent limiter ou favoriser le transfert d'espèces entre les deux fluides. La structure de ces interfaces doit être connue en fonction de plusieurs paramètres thermodynamiques pour pouvoir déterminer le paysage énergétique associée. La réflectivité de neutrons et de rayons est un des outils appropriés pour sonder ce genre d'interfaces enfouies et fluctuantes à l'échelle nanométrique et à l'équilibre. Pour cette étude, une nouvelle cellule a été construite et un programme spécifique d'analyse de données a été élaboré.Nous avons également porté notre étude sur deux différents systèmes bi-phasiques (eau / dodécane) contenant des sels de lanthanides et deux différents ligands non ioniques (ou extractants) : une diamide de type DMDBTDMA et de type DMDOHEMA, ces deux extractants étant connus pour avoir des comportements différents dans un processus d'extraction de cations métalliques en phase organique. Bien que la structure amphiphile des deux diamides soit bien connue, la structure de l'interface liquide / liquide semble être différente de celle que l'on pourrait s'attendre avec des tensioactifs classiques. L'organisation de ces ligands à l'interface est en effet plus complexe, varie en fonction de leurs concentrations dans la phase organique (seules des concentrations inférieures à la concentration d'agrégation critique ont été étudiées) et en fonction de la concentration d'acide et de sel dans la phase aqueuse. Une organisation de type monocouche n'est pas l'organisation principale de ces systèmes à l'équilibre mais on observe plutôt une couche épaisse de ligands.Plus précisément, dans le cas de la DMDBTDMA, cette région plus épaisse (environ trois à quatre fois la longueur du ligand) crée une région interfaciale où les molécules d'huile et d'eau peuvent se mélanger ainsi que les sels. Le système DMDOHEMA, présente une structuration différente avec également une épaisse couche de ligand (environ deux fois la longueur du ligand) mais située plus à l'intérieur de la phase huileuse et distinct de la distribution des sels à l'interface. Ces différentes structures interfaciales de DMDBTDMA et DMDOHEMA peuvent permettre d'expliquer les différents régimes de transfert ionique qualifiés soit de diffusionnel ou de cinétiqueIn the frame of the nuclear waste reprocessing and various kinds of critical metals recycling methods, solvent extraction is one of the most used technological processes. The liquid interface between two immiscible fluids is considered as a region where many physical and chemical phenomena take place and can limit or promote the transfer of species between both fluids. The structure of these interfaces has to be known as a function of several thermodynamical parameters to be able to determine the associated energy landscape. X-ray and neutron reflectivity are suitable techniques to probe such kind of fluctuating and buried interfaces at the nanometer scale and at equilibrium. For this study, a new cell has been built and a specific data analysis procedure was established.We have focused our study on two different biphasic systems (water/dodecane) containing lanthanides salts and two different nonionic ligands or extractant molecules: DMDBTDMA and DMDOHEMA diamides. These ligands are known to have different behaviour in the lanthanides extraction process. Although the amphiphilic chemical structure of both diamides is well known, the structure of the liquid/liquid interface appears to be different as those expected for a classical surfactant molecule. This structure looks more complex, varies as a function of the ligand concentration in the organic phase (below the critical aggregation concentration) and as a function of the proton and salt concentration of the aqueous phase. A monolayer organization does not appear as the main interfacial structuration and a thicker organic layer with an excess of salt has to be considered.In the case of the DMDBTDMA, this thicker region (approximatively three or four times the length of the ligand) creates an interfacial region where oil and water molecules as well as some salts can mix in. The DMDOHEMA system shows a different structuration where we can roughly observe also a thick layer of the ligand (approximatively two times the length of the ligand) but located more within the oil phase and forming a barrier to the salt distribution. These different interfacial structures made of DMDBTDMA and DMDOHEMA could allow to explain the diffusive or kinetic regime of ion transfer observed respectively in similar systems by others authors
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Lauterbach, Tim, Thomas Walther, Michael Grösel, Stephan Lenk, T. Gernandt, R. Moll, F. Seidel, et al. "Sens-o-Spheres – Mobile, miniaturisierte Sensorplattform für die ortsungebundene Prozessmessung in wässrigen Lösungen." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-236018.
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Zur Prozessmessung in Flüssigkeiten wird ein Konzept vorgestellt, das mittels miniaturisierter Sensorkugeln eine ortsveränderliche Aufnahme von Prozessmesssignalen – z. B. der Temperatur – ermöglicht und diese kontinuierlich aus dem Reaktionsvolumen an eine Basisstation überträgt. Das System beinhaltet nicht nur die Miniaturisierung der Messstelle auf einen Kugeldurchmesser von 7,8 mm sondern auch die Abstimmung der Gesamtdichte auf die Prozessbedingungen, um eine gleichmäßige Verteilung der Messpunkte auf das gesamte Reaktionsvolumen zu ermöglichen. Für die Verwendung im Bioprozess wurde eine bio-inerte Kapselung für die gesamte Messelektronik entwickelt und die Funktionstüchtigkeit in mehreren Bioreaktorsystemen demonstriert. Das Messsystem wird mit einer induktiv wieder aufladbaren Energiequelle betrieben und hat eine Reichweite von mehr als 30 cm durch die Flüssigkeitssäule.
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Garcia, Marlon Rodrigues [UNESP]. "Aplicação de sensor de deslocamento angular em fibra óptica para medição de concentração de líquidos via ondas acústicas guiadas." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/138009.
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Neste trabalho aborda-se a utilização de um sensor de deslocamento angular em fibra óptica para a caracterização de líquidos utilizando-se ondas de Lamb e o modo quase Scholte (QSCH) propagados em placa metálica. O sensor reflexivo compreende duas fibras ópticas, uma emissora e outra receptora, uma lente positiva, uma superfície reflexiva, um laser e um fotodetector. Primeiramente, realiza-se um breve estudo sobre a propagação de ondas mecânicas guiadas em placas metálicas imersas em fluidos. Nesse estudo, são obtidas as curvas de dispersão para a velocidade de fase e para a velocidade grupo em função do produto frequência-semiespessura da placa, tanto para as ondas de Lamb quanto para o modo QSCH, considerando diferentes fluidos. Posteriormente, aborda-se o modelamento matemático do sensor reflexivo, obtendo-se as curvas características estáticas para quatro diferentes configurações. Em seguida, descreve-se o processo de montagem do sensor reflexivo, com todos os seus detalhes construtivos. Já na parte experimental, aplicando-se um pulso senoidal de envoltória gaussiana em um transdutor, investiga-se primeiramente a excitação do modo fundamental simétrico da onda de Lamb, S0. Captando-se simultaneamente os sinais da onda propagada na placa pelo sensor reflexivo e por uma piezocerâmica em modo de recepção, obtêm-se os valores experimentais da velocidade de grupo. Comparando-se os valores experimentais com os valores teóricos previstos pelas curvas de dispersão, percebe-se que o sensor reflexivo pode ser utilizado para se medir modos simétricos da onda de Lamb.Visando-se a caracterização de líquidos, imerge-se parcialmente uma placa de alumínio em um fluido sob teste, e excita-se o modo fundamental antissimétrico da onda de Lamb, A0. O modo A0 converte-se em modo QSCH na interface ar-fluido, o qual sofre reflexão na borda da placa e se reconverte em modo A0 na interface fluido-ar. Utilizando-se o sensor reflexivo, pode-se medir a velocidade de propagação do modo QSCH. Sabendo-se que a velocidade do modo QSCH é diferente para diferentes fluido, verifica-se que o sensor pode ser utilizado para medir porcentagens de misturas de fluidos. Adicionalmente, medem-se também os deslocamentos lineares gerados pelo modo A0 na placa de alumínio na direção out-of-plane, comparando-se os resultados com as medições realizadas por um interferômetro de Michelson.
In this work one approaches the use of an angular displacement optical fiber sensor for characterization of liquids using Lamb waves and quasi-Scholte waves (QSCH) propagated in a metal plate. The reflective sensor comprises two optical fibers, one emitting and another receiving, a reflective surface, a laser and a photodetector. Firstly, one develops a brief study about the propagation of mechanical waves in metal plates imbibed in fluids. In this study, one obtains the dispersion curves for the phase velocity and the group velocity as a function of the frequency-halfwidth product for both Lamb waves and QSCH mode, considering different fluids. Subsequently, it one approaches the mathematical modeling of the reflective sensor, obtaining the static characteristic curves for four different configurations. Next, one describes the assembly process of the reflective sensor, with all the construction details. In the experimental part, one investigates the excitement of the symmetrical fundamental mode of the Lamb wave applying a sinusoidal pulse of gaussian envelope. Catching up simultaneously the wave propagated signals by the reflective sensor and by a piezoceramic, one obtains the experimental values of the group velocity. Comparing the experimental values with the values proposed by the dispersion curves, one notices that the reflective sensor can be used to measure the symmetric modes of the Lamb waves. Aimed at the characterization of liquids, one immerges partially an aluminum plate in a fliud under test, and one excites the fundamental antisymmetric mode of the Lamb wave, A0. The A0 mode becomes QSCH in the air-fluid interface, which reflects in the edge of the plate and is reconverted into A0 mode in the fluid-air interface. Using the reflective sensor, one can measure the QSCH mode propagation velocity. Knowing that the QSCH velocity is different for different fluids, one verifies that the sensor can be used to measure percentages of fluid mixtures. One measures also the linear displacements generated by the A0 mode in the aluminum plate in the out-of-plane direction, comparing the results with the measurements made by a Michelson interferometer.
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Garcia, Marlon Rodrigues. "Aplicação de sensor de deslocamento angular em fibra óptica para medição de concentração de líquidos via ondas acústicas guiadas /." Ilha Solteira, 2016. http://hdl.handle.net/11449/138009.
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Orientador: Cláudio KitanoResumo: Neste trabalho aborda-se a utilização de um sensor de deslocamento angular em fibra óptica para a caracterização de líquidos utilizando-se ondas de Lamb e o modo quase Scholte (QSCH) propagados em placa metálica. O sensor reflexivo compreende duas fibras ópticas, uma emissora e outra receptora, uma lente positiva, uma superfície reflexiva, um laser e um fotodetector. Primeiramente, realiza-se um breve estudo sobre a propagação de ondas mecânicas guiadas em placas metálicas imersas em fluidos. Nesse estudo, são obtidas as curvas de dispersão para a velocidade de fase e para a velocidade grupo em função do produto frequência-semiespessura da placa, tanto para as ondas de Lamb quanto para o modo QSCH, considerando diferentes fluidos. Posteriormente, aborda-se o modelamento matemático do sensor reflexivo, obtendo-se as curvas características estáticas para quatro diferentes configurações. Em seguida, descreve-se o processo de montagem do sensor reflexivo, com todos os seus detalhes construtivos. Já na parte experimental, aplicando-se um pulso senoidal de envoltória gaussiana em um transdutor, investiga-se primeiramente a excitação do modo fundamental simétrico da onda de Lamb, S0. Captando-se simultaneamente os sinais da onda propagada na placa pelo sensor reflexivo e por uma piezocerâmica em modo de recepção, obtêm-se os valores experimentais da velocidade de grupo. Comparando-se os valores experimentais com os valores teóricos previstos pelas curvas de dispersão, percebe-se que... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: In this work one approaches the use of an angular displacement optical fiber sensor for characterization of liquids using Lamb waves and quasi-Scholte waves (QSCH) propagated in a metal plate. The reflective sensor comprises two optical fibers, one emitting and another receiving, a reflective surface, a laser and a photodetector. Firstly, one develops a brief study about the propagation of mechanical waves in metal plates imbibed in fluids. In this study, one obtains the dispersion curves for the phase velocity and the group velocity as a function of the frequency-halfwidth product for both Lamb waves and QSCH mode, considering different fluids. Subsequently, it one approaches the mathematical modeling of the reflective sensor, obtaining the static characteristic curves for four different configurations. Next, one describes the assembly process of the reflective sensor, with all the construction details. In the experimental part, one investigates the excitement of the symmetrical fundamental mode of the Lamb wave applying a sinusoidal pulse of gaussian envelope. Catching up simultaneously the wave propagated signals by the reflective sensor and by a piezoceramic, one obtains the experimental values of the group velocity. Comparing the experimental values with the values proposed by the dispersion curves, one notices that the reflective sensor can be used to measure the symmetric modes of the Lamb waves. Aimed at the characterization of liquids, one immerges partially an alumi... (Complete abstract click electronic access below)
Mestre
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Alabdullah, Sahar Samir Mohammed. "pH measurements in ionic liquids." Thesis, University of Leicester, 2018. http://hdl.handle.net/2381/42877.
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Deep eutectic solvents (DESs) and ionic liquids (ILs) have been significantly used in a variety of applications and one of the challenges is to understand the behaviour of protons in these non-aqueous media. The aim of this study is to investigate pH scales in DESs and ILs and to use the values to understand processes which occur in these media. The first stage of the study involved the development of a spectroscopic analytical method for measuring effective proton activity in IL media. Its pKIn data for bromophenol blue as an indicator were obtained in DESs and ionic liquids and it was found that the pKIn was influenced by the amount of the salt in the system. The value of pKIn was lower in DESs and ILs than in water. pKIn values were used to obtain pKa values for different organic acid in variety of DESs and in two different imidazolium-based ILs containing different anions. The order of acidity is controlled by the element of the anion within it and it was found that F- > HSO4-> Cl-> Ac- suggesting some correlation with hydrogen bond strength. In the second stage of this study a glass membrane electrode was used for the first time in DESs and ILs. The investigation successfully measured the pH scales of different DESs. It was shown that the response of a glass electrode was almost Nernstian in a DES with minimal water incorporated. The Nernstian slope increased as more water was added to the DES. A new, non-aqueous glass electrode was also made using Ag/AgCl in Ethaline reference electrodes. It was shown that this also had a Nernstian response showing that the glass membrane could function with only the traces of water naturally incorporated in the DESs. In the final part of this study the pH values of DESs were used to investigate the solubility of metal oxides in different DESs and the solubility was found to correlate well with the pH of the liquid. The formation of polyaniline was invetgated in solutions of differing pH both with and without water. The data showed the effect of both pH and mass transport on the rate of film growth. It was found that pH was not directly related to polymer growth rate but it showed that polymer only grew when an emulsion of monomer formed in solution. This significant discovery was only enabled by quantification of solution pH.
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Gladish, James Campbell. "Revealing Structural Organization with Liquid Crystal-based Spectral Imaging Polarimetry." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2325.
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Structural organization refers to the particular ordering of scatterers. Probing structural organization by imaging polarized spectral scatter provides insight into the composition of a medium, and can aid in remote sensing, the identification of tissue pathologies, and material characterization and differentiation. The vector nature of polarized light enables it to interact with optical anisotropies within a medium, while the spectral aspect of polarization is sensitive to small-scale structure. However, many polarization studies have limitations, as they provide qualitative image analysis, incomplete anisotropy information, or both. The ability to image the effects of anisotropy and small-scale structure at multiple wavelengths is key for parameterizing structural organization. The Stokes/Mueller formalism is a framework that quantifies a medium's complete spectral polarization response, and allows for the parameterization of structural organization. Additionally, advances in liquid crystal (LC) technology have resulted in new polarimetric devices. These computer-controlled devices impart spectral polarization effects on the millisecond timescale with no mechanically moving hardware, providing the ability for making rapid polarimetric measurements. This dissertation describes a methodology for revealing structural organization by exploiting the Stokes/Mueller formalism and by utilizing measurements from a spectral imaging polarimeter constructed from variable retardance LC devices, such as liquid crystal variable retarders (LCVRs) and a liquid crystal tunable filter (LCTF). The methodology includes developing the system, the Stokes/Mueller model, and all of the procedures, calibrations, and data interpretation. Developing the system also consists of component and system calibration, a system sensitivity and performance analysis, and finally test measurements for system validation. The final validation measurement is made on a mineral sample for inferring structural organization.
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Male, John Christie. "Liquid surface measurement in stereolithography." Thesis, Brunel University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343290.
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Li, Yuet Wing. "Liquid crystal pretilt angle measurement /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202003%20LIY.
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Varanda, Fátima Rodrigues. "Measurement of liquid-liquid equilibrium of fluorous biphasic systems." Master's thesis, Universidade de Aveiro, 2007. http://hdl.handle.net/10773/2986.
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Mestrado em Engenharia QuímicaA catálise heterogénea é usada em 80% dos processos industriais catalíticos porque envolve uma fácil separação dos reagentes e produtos da reacção. A catálise homogénea, por sua vez, apresenta a grande vantagem de se poder usar diversos modelos capazes de descrever e prever as propriedades da mistura reaccional, embora apresente uma difícil separação e recuperação dos compostos envolvidos. A catálise bifásica consegue reunir as vantagens de ambos os tipos de catálise homogénea e heterogénea. Este método consiste em utilizar dois solventes imiscíveis a temperatura ambiente, onde o catalisador encontrase imobilizado em uma fase e os reagentes na outra. Através de um aumento da temperatura formase uma única fase onde ocorre a reacção. Ao arrefecer, as fases separamse permitindo a separação dos produtos e do catalizador, que pode ser reutilizado. Em particular, desde a primeira publicação, em 1994, que Horváth e Rábai demonstraram que os sistemas bifásicos fluorados podem ser altamente vantajosos em uma grande variedade de reacções químicas orgânicas, usando perfluorocarbonetos como meio de reacção. Este trabalho tem como principal objectivo o estudo do equilíbrio líquidolíquido de sete novos sistemas binários contendo compostos fluorados e solventes orgânicos, contribuindo com novos dados experimentais e teste de modelos nestes sistemas. O método utilizado foi a turbidimetria, usando um método dinâmico de detecção visual. Foram preparadas várias ampolas com composições diferentes para cada sistema. A mistura foi aquecida em um banho termostatizado a uma temperatura onde apenas uma fase era observada. Ao arrefecer lentamente essa mistura, observouse a separação das fases e a respectiva temperatura foi registada. Os resultados obtidos foram correlacionados coma dois modelos que usam diferentes abordagens. A equação de estado softSAFT foi utilizada para correlacionar os dados experimentais de forma satisfatória. O COSMORS, modelo baseado em cálculos de química quântica foi utilizado para prever o comportamento das solubilidades mútuas dos compostos envolvidos, tendose verificado uma ferramenta útil no caso de sistemas envolvendo tolueno e acetonitrilo.
Due to the easy separation of the reactants from reaction products, almost 80% of industrial catalytic reactions use heterogeneous catalysts. The homogeneous catalysis has the great advantage that models can be used to describe and predict the properties of the species involved in the catalytic reaction, but its main limitation is the separation and recovery of the products from the catalyst. The biphasic catalysis gather the advantages of both types of catalysis. This method consists on using two solvents which are immiscible at room temperature maintaining the catalytic system immobilized in one phase while the reactants and products remain in the other phase. By rising the temperature, the mixture becomes completely miscible allowing reactions to proceed homogeneously. On cooling, the phases separate allowing the facile catalyst/product separation. Since the first publication in 1994, by Horváth and Rábai, fluorous biphasic systems (FBS) have shown to have advantages in a wide variety of chemical organic reactions including catalytic reactions, using perfluorocarbons (PFC) as reaction media. The aim of this work is the study of liquidliquid equilibrium (LLE) of seven original binary systems containing highly fluorinated compounds and an organic solvent. This work contributes with new experimental LLE data of fluorous biphasic systems, measured using turbidimetry with naked eye visual detection. Several ampoules were prepared with different compositions for each system. The mixture was heated in a thermostatic bath until just one phase was observed. On slowly cooling, the phase separation temperature was registered. The obtained results were modeled using two different approaches. The softSAFT equation of state was used successfully to correlate the experimental data. COSMORS, a predictive method based on unimolecular quantum chemical calculations for individual molecules, was used to predict the phase behavior of the involved compounds and revealed to be a special useful tool in the case of toluene and acetonitrile mixtures.
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Younis, Ossied Adel Dourgham. "The measurement,correlation and prediction of multicomponent liquid-liquid and vapour-liquid-liquid equilibria." Thesis, Teesside University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425971.
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Hägerbrand, Jonathan. "Measurements of resistivity in transformer insulation liquids." Thesis, Uppsala universitet, Institutionen för elektroteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-413804.
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This thesis focuses on measuring techniques and results of resistivity in four commercially available insulating transformer oils: mineral oil, ester oil and two isoparaffin oils. Two measuring techniques, the industrially used diagnostic system for electrical insulation IDA and the Labview implemented Triangular Method, are used for resistivity measurements and the techniques are compared, a correction algorithm to the triangular method is suggested. Dielectric properties of mineral & ester and isoparaffin A&B mixtures are investigated, it is experimentally shown that the transformer oils that show high resistivity also show low loss factor. The effect moisture has on resistivity in mineral and ester oil are shown both in terms of relative humidity and actual water content in parts per million. A previous measurement cell is redesigned, the cell is manufactured in copper and gold. It is found that the material choice of the cell significantly affects the resistivity measurements. The electrical double layer and contact resistance between the oil and cell are investigated as a way to explain the difference in measured resistivity. These experiments are limited to the mineral oil and isoparaffin oil A, it is found that contact resistance is a plausible explanation. The electrical double layer is fairly constant for both oils and the Debye length of the double layer is negligible compared to the total distance between the electrodes of the cell. Lastly, the field of insulating transformer oils and its future is discussed, from data obtained regarding the dielectric properties and environmental aspects of the four transformer oils used in this study. A positive trend which combines the high insulating properties with good biodegradability qualities is found. Suggesting a positive future in the field of insulating transformer oils. The results found in this thesis can be used as a basis for future theses regarding transformer oils used for HVDC applications.
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Marasli, Necmettin. "The measurement of solid-liquid surface energy." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260154.
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Ortman, Jerker. "Improvement of conductivity measurement in liquid chromatography." Thesis, Uppsala universitet, Institutionen för elektroteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-448059.
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In liquid chromatography the ability to measure the conductivity is essential toreach a good result. This is done by applying a current through the electrolyte ofinterest and measuring the voltage drop over the electrolyte. The conductivity isthen calculated with the known current and the measured voltage. It is of highimportance that it is an AC-current to avoid polarization at the electrodes of thesensor. With the AC-current a frequency must be chosen to reach the most accurateresult. This is hypothetically done where the phase is as low as possible. An electricequivalent circuit and previous work was used as a starting point in the work offinding the best frequency algorithms that would give the lowest phase. Afterseveral measurements with different frequency algorithms it could be seen that thecurrent algorithm is plenty good and that at the moment it is not worth it to improveit further. The sensor in this thesis, chip LFS155 from IST AG, Switzerland, wassaid to have an linear cell constant between 0.1-200 mS/cm. So after multiplemeasurements on five different LFS155 sensors it could be seen that in the regions oflower conductivity as well as higher conductivity the cell constant could be adjustedfora better result. The adjustments were done by excels curve fitting function andimplemented witha good result. The demands on the accuracy for the sensor tomeasure conductivity could be improved. In the lower part of conductivity spectra(<0.1 mS/cm) the promised accuracy went from±0.02 mS/cm to±0.005 mS/cm.In the higher end of the conductivity spectra (>100 mS/cm) itwas changed from±4 % to±2 %
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Joakim, Eck. "Development of systematic measurement on liquid metal." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-75347.
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The most common way of producing steel worldwide is with the continuous casting process, where a strand of steel is continuously cast. Further optimization of this process requires data from measurements, measurements which must take place in a hostile high-temperature and corrosive environment such as liquid steel. At Swerim, a Continuous Casting Simulator has been constructed to replicate the flow conditions in the process. A eutectic bismuth-tin alloy with properties similar to steel is used instead to make measurements in liquid metal possible. In this report pressure, velocity and vibration measurements were made using multiple sensors under different flow conditions.
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Batey, G. J. "Thermal measurements in helium." Thesis, University of Nottingham, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376489.
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Diette, Christophe. "Measurement and analysis of forced convection phenomena in blade cooling channels." Valenciennes, 2003. http://ged.univ-valenciennes.fr/nuxeo/site/esupversions/c76547a4-820c-48f8-9717-ced740f0cb38.
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Dealing with gas turbine aircraft engines, the Turbine Entry Temperature (TET) is generally targeted as high as possible. Increasing this parameter leads to higher thermodynamic efficiency and power output and reduces the weight-to-thrust ratio and the Specific Fuel Consumption (SFC). Since the maximum permissible TET is determined by the temperature limitations of the turbine assembly, the choice of turbine material and the design of cooling systems applied to turbine blades are essential. This work reports both an experimental and numerical investigation on internal blade cooling cavities. Various cross sections are examined depending on the region of the blade to cool down. Numerous parameters regarding the promoters of turbulence and the flow conditions are varied to find an optimum solution in terms of both heat transfer and pressure losses. Numerical simulations are performed to support the analysis of the flow behaviour. A good agreement is found between the simulations and the aerodynamic measurements. Theoretical diagrams to interpret the flow field are finally proposed. This study provides a better understanding of flow features occuring in cooling channels together with a very detailed database. The later is useful for further numerical validations and the optimisation of cooling cavitiesEn matière de moteurs d'avion à turbine à gaz, une Température d'Entrée de Turbine (TET) aussi élevée que possible est souhaitée. Augmenter sa valeur permet en effet d'obtenir un rendement thermodynamique plus élevé tout en réduisant le rapport poids-poussée et la consommation spécifique (SFC). Parce que la TET maximum permise est liée aux limites de température supportées par les composants de la turbine, le choix des matériaux et la conception des circuits de refroidissement d'aubes sont cruciaux. Cette recherche rend compte d'une étude expérimentale et numérique sur les cavités internes de refroidissement d'aubes. Des sections de passage différentes sont examinées, en fonction de la région de l'aube à refroidir. Plusieurs paramètres en ce qui concerne les promoteurs de turbulence et les conditions de l'écoulement, sont variés pour définir une solution optimale en termes de transfert de chaleur et pertes de charges. Des simulations numériques sont réalisées pour appuyer l'analyse de l'écoulement. La comparaison de ces résultats avec les mesures aérodynamiques se révèle très satisfaisante. Enfin, des diagrammes sont proposés, pour décrire l'écoulement dans chaque cavité étudiée. De cette étude, il ressort une meilleure compréhension des phénomènes mis en jeu dans les cavités de refroidissement, ainsi qu'une base de données détaillée. Cette dernière est utile pour la validation de codes de calcul et l'optimisation des systèmes de refroidissement
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Koos, Erin Crystal Hunt Melany L. Hunt Melany L. "Rheological measurements in liquid-solid flows /." Diss., Pasadena, Calif. : Caltech, 2009. http://resolver.caltech.edu/CaltechETD:etd-03032009-092653.
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Carvalho, Pedro Jorge Marques de. "Measurements of thermophysical properties of perfluorocarbons and ionic liquids." Master's thesis, Universidade de Aveiro, 2008. http://hdl.handle.net/10773/2992.
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Mestrado em Engenharia QuímicaNo presente trabalho propõe-se estudar a tensão superficial de vários perfluorocarbonetos lineares, cíclicos, aromáticos e [alfa]-substituídos bem como líquidos iónicos com o catião imidazolium em comum. Apesar do seu interesse inerente, informação sobre esta propriedade para os compostos seleccionados é escassa e quando disponível apresenta discrepâncias consideráveis entre si. As medições foram realizadas no intervalo de temperaturas (283 to 353) K usando o método do anel de Du Noüy. Para os fluorocarbonetos, os dados experimentais demonstram que a estrutura molecular é o factor primordial no comportamento da superfície uma vez que os fluorocarbonetos aromáticos apresentam a tensão superficial mais elevada, seguida pelos fluorocarbonetos cíclicos e substituídos. Os perfluorocarbonetos lineares apresentam os menores valores de tensão superficial, aumentando ligeiramente com o aumento do número de carbonos. Os líquidos iónicos estudados foram seleccionados com o objectivo de fornecerem um estudo compreensivo sobre a influência do tamanho da cadeia alquílica do catião, o número de substituições no catião e a influência do anião. A influência do conteúdo de água na tensão superficial foi estudada em função da temperatura e da fracção molar de água para o liquido iónico mais hidrofóbico, [omim][PF6], e para o mais higroscópico, [bmim][PF6]. As funções termodinâmicas de superfície, como a entropia e entalpia de superfície, foram derivadas a partir da dependência da tensão superficial com a temperatura. Os dados obtidos para o fluorocarbonetos foram comparados com a correlação proposta por Faizullin, apresentando um desvio inferior a 4 % e demonstrando a sua aplicabilidade para com esta classe de compostos. A metodologia adoptada neste trabalho requer o conhecimento das densidades dos compostos de modo a aplicar a necessária correcção hidrostática. Contudo, para os líquidos iónicos esta informação é limitada ou mesmo inexistente. Por este motivo realizaram-se medições de densidade em função da pressão (0.10 < p/MPa < 10.0) e da temperatura (293.15 < T/K < 393.15). Desta dependência, as propriedades termodinâmicas, tais como compressibilidade isotérmica, expansividade isobárica, coeficiente térmico da pressão e dependência da capacidade calorífica com a pressão foram investigadas. A influência do teor de água na densidade foi também estudada para o líquido iónico mais hidrofóbico, [omim][PF6]. Um modelo simples de volume-ideal foi aplicado de forma preditiva para os volumes molares dos líquidos iónicos, em condições ambientais, descrevendo bem os dados experimentais. ABSTRACT: This work aims at studying the surface tension of some linear, cyclic, aromatic, [alfa]-substituted perfluorocarbons and imidazolium based ionic liquids. Despite its fundamental interest, information about this property for these compounds is scarce and the available data present strong discrepancies among each other. The measurements were carried out in the temperature range (283 to 353) K with the Du Noüy ring method. For the fluorocarbons, the analysis of the experimental data shows that the molecular structure is the main factor in the surface since the aromatic fluorocompounds present the highest surface tensions, followed by the cyclic and substituted fluorocompounds. The linear n-perfluoroalkanes exhibit the lowest surface tension values, slightly increasing with the carbon number. The set of selected ionic liquids was chosen to provide a comprehensive study of the influence of the cation alkyl chain length, the number of cation substitutions and the anion on the properties under study. The influence of water content in the surface tension was studied for several ILs as a function of the temperature as well as a function of water mole fraction, for the most hydrophobic IL investigated, [omim][PF6], and one hygroscopic IL, [bmim][PF6]. The surface thermodynamic functions such as surface entropy and enthalpy were derived from the temperature dependence of the surface tension values. The perfluorocarbons experimental data were compared against the Faizullin correlation, and it is shown that this correlation describes the measured surface tensions with deviations inferior to 4 %. The methodology adopted in this work requires the knowledge of the densities of the compounds under study in order to apply an hydrostatic correction. However, for ionic liquids these information is scarse and in some cases unavailable. Therefore, experimental measurements of the pressure (0.10 < p/MPa < 10.0) and temperature (293.15 < T/K < 393.15) dependence of the density and derived thermodynamic properties, such as the isothermal compressibility, the isobaric expansivity, the thermal pressure coefficient, and the pressure dependence of the heat capacity of several imidazolium-based ionic were determined. The influence of water content in the density was also studied for the most hydrophobic IL used, [omim][PF6]. A simple ideal-volume model was employed for the prediction of the imidazolium molar volumes at ambient conditions, which proved to agree well with the experimental results.
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Chang, Yao-Ting. "An investigation of liquid velocity measurement using PZT cylinders." Thesis, Cape Peninsula University of Technology, 2006. http://hdl.handle.net/20.500.11838/2209.
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Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2006.A novel ultrasonic velocimeter was developed in this study using a single element PZT cylinder encapsulated within an isothermal cavity. The rig was designed to hold a small sample volume of test liquid (typically less than 0.2ml), as a prerequisite for biological application. An admittance spectrum for the liquid filled cavity displayed sharp piezoelectric modes indicating strong coupling between the cylinder and liquid. This coupling was further improved by using liquid soap as a coupling agent. The phase velocity was measured, using the change in frequency associated with change in acoustic mode number. Early results indicated a change in frequency, with mode number decrease over the superimposed piezoelectric resonance providing a skewed value for phase velocity. This problem is evidenced in the literature precluding continuous wave interferometry as a realisable means of measuring phase velocity. This study examines the common problem of frequency pulling and resonant interaction between acoustic and piezoelectric modes. For the first time an alternative is shown to traditional "electro-acoustic" models, utilising an extension of Mason's transmission line model with the addition of a "mechanical-acoustic" transformer to represent energy coupling between the piezoelectric and surrounding liquid. It was found the transformer coupling coefficient could be described as the inner surface area of the cylinder. In an attempt to quantify the behaviour of this model it has been simplified into an "electro-acoustic" equivalent lumped circuit elements. Each liquid mode is represented as a series tuned LeR circuit. The solution to the frequency pulling was unravelled by implementing a stochastic optimiser (adaptive mutation breeder algorithm) to predict the coupling coefficient between mechanical and acoustic modes. It also predicts acoustic equivalent circuit parameters and further utilise it to extract the velocity of sound from the test liquid. Three test liquids were evaluated including water, FC43 and FC75 at a constant temperature of 30 °C±O.Ol "C. Initial results indicate a strong correlation between the model and experiment with accumulative admittance errors falling below 5%. Subsequently it was possible to achieve phase velocity measurements with a "worst case" standard deviation of less than 3.74. It has been the hypothesis of this study to show, in concept, that inline tube velocimeter is plausible using continuous wave cylindrical interferometry.
National Research Foundation
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Narasigadu, Caleb. "Design of a static micro-cell for phase equilibrium measurements : measurements and modelling." Paris, ENMP, 2011. https://pastel.hal.science/pastel-00679369.
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Cette étude couvre la conception d'un nouvel appareil qui permet la mesure fiable de pressions de vapeur d'équilibres à plusieurs phases à partir de petits volumes (un maximum de 18 cm3). Les mesures d'équilibres de phase concernant la présente étude incluent : des équilibres "liquide-vapeur" (ELV), "liquide-liquide" (ELL) et " liquide-liquide-vapeur" (ELLV). La température de fonctionnement de l'appareil s'étend de 253 à 473 K pour une pression de fonctionnement qui s'étend du vide absolu à 1600 kPa. Le prélèvement des phases est réalisé grâce au Rapid On line Sampling Injector (ROLSI™). Une technique originale est ajoutée en complément du ROLSI™ pour éviter des chutes de pressions lors du prélèvement. Cette technique utilise une tige métallique afin de compenser les changements de volume lors des prélèvements. Des mesures de tensions de vapeur et d'équilibres de phase ont été entreprises pour caractériser le fonctionnement de l'appareil conçu et développé. Ensuite de nouvelles mesures de tensions de vapeur et d'ELV ont été mesurées sur des systèmes intéressant les compagnies pétrochimiques. Les données expérimentales de pression de vapeur obtenues ont été régressées en utilisant les équations étendues d'Antoine et de Wagner. Les données expérimentales d'ELV mesurées ont été régressées avec des modèles thermodynamiques au moyen des méthodes directes et combinées. Pour la méthode directe les équations d'état de Soave-Redlich-Kwong et de Peng-Robinson ont été employées avec la fonction (α) de Mathias et Copeman (1983) dépendante de la température. Pour la méthode combinée, l'équation du viriel (deuxième coefficient du viriel de la corrélation de Tsonopoulos (1974)) a été employée associée à un modèle de solution (coefficient d'activité) pour la phase liquide: TK-Wilson, NRTL et UNIQUAC modifié. Des tests de cohérence thermodynamique ont été exécutés pour toutes les données expérimentales de VLE mesurées. Presque tous les systèmes mesurés ont déclarés thermodynamiquement cohérents (test de point de Van Ness et autres (1973) et test direct de Van Ness (1995)This study covers the design of a new apparatus that enables reliable vapour pressure and equilibria measurements for multiple liquid and vapour phases of small volumes (a maximum of 18 cm3). These phase equilibria measurements include: vapour-liquid equilibrium (VLE), liquid-liquid equilibrium (LLE) and vapour-liquid-liquid (VLLE). The operating temperature of the apparatus ranges from 253 to 473 K and the operating pressure ranges from absolute vacuum to 1600 kPa. The sampling of the phases is accomplished using a single Rapid-OnLine-Sampler-Injector (ROLSITM). A novel technique is used to achieve sampling for each phase. The technique made use of a metallic rod in an arrangement to compensate for volume changes during sampling. As part of this study, vapour pressure and phase equilibrium data were measured to test the operation of the newly developed apparatus. New experimental vapour pressure and VLE data were also measured for systems of interest to petrochemical companies. The experimental vapour pressure data obtained were regressed using the extended Antoine and Wagner equations. The experimental VLE data measured were regressed with thermodynamic models using the direct and combined methods. For the direct method the Soave-Redlich-Kwong and Peng-Robinson equations of state were used with the temperature dependent function (α) of Mathias and Copeman (1983). For the combined method, the virial equation of state with the second virial coefficient correlation of Tsonopoulos (1974) was used together with one of the following liquid-phase activity coefficient model: TK-Wilson, NRTL and modified UNIQUAC. Thermodynamic consistency testing was also performed for all the VLE experimental data measured where almost all the systems measured showed good thermodynamic consistency for the point test of Van Ness et al. (1973) and direct test of Van Ness (1995)
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Pink, Clive Desmond. "Liquid level measurement using a coplanar transmission line." Master's thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/8326.
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Bibliography: leaves 93-94.The coplanar line has been used very successfully as an element in microwave circuits. Small size, high Q-factor, and accurate reproduction, are some of its many advantages. The coplanar transmission lines discussed in this report, are targeted at liquid level measurement, and are typically 30 cm. long. Their operating frequencies are consequently much lower than those of microwave coplanar waveguides, but they have common advantages. The factor which separates the coplanar line from similar liquid level sensors, is that it makes use of the electrical component of the electromagnetic fringe field, setup between its inner conductor, and the surrounding ground plane. The line is effectively a sharply tuned resonator, incorporated as the frequency controlling element of an electronic oscillator. The output frequency falls as a dielectric material penetrates the fringe field. An impressive sensitivity is accomplished by using very thin conductors, thereby ensuring that the fringe field energy is maximised. The most important feature of this sensor is its ability to operate non-intrusively when used with non-conducting vessels, or if employed in a metal tank, the unit can be encased in a dielectric material where the line is non-contacting (the liquid does not penetrate the unit). This combined with its excellent mechanical and electrical stability, and an accuracy better than 1 percent, makes the coplanar line a strong competitor in the field of liquid level measurement. The research began with a theoretical approach, and used lines machined from an Aluminium plate for characteristic impedance measurement. An empirical relation between the gap width, the line thickness, and the characteristic impedance of the line is presented. To assist with the design of the sensor, a lumped capacitance model of the line was developed. Various geometries were tested, and modified until a near linear response to water level was achieved. An advanced engineering model of the level sensor has been developed, which incorporates a stable digital output display, user calibration from the line's end points, and temperature compensation. A T-shaped line, which concentrates the field around its open end, was used for other applications such as, evaporation monitoring, measurement of slurry settlement, and to observe the effect of acids, bases, and salts in water. Various applications of the different coplanar line designs are proposed.
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LI, LI. "NANOSCALE CHARGE DENSITY MEASUREMENT IN LIQUID WITH AFM." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1599744539112356.
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Taylor, R. M. "Optical sensing techniques for liquid level gauging." Thesis, University of Kent, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380619.
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Zhang, Xuewei. "Keer electro-optic measurements in liquid dielectrics." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/91035.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references.
Kerr electro-optic technique has been used to measure the electric field distribution in high voltage stressed dielectric liquids, where the difference between refractive indices for light polarized parallel and perpendicular to the local electric field is a function of the electric field intensity. For transformer oil, the most widely-used insulating liquids in power apparatus and high voltage technology, Kerr effect is very weak due to its low Kerr constant. Previous Kerr measurements have been using ac modulation technique, which is only applicable to dc steady-state electric field mapping while various instabilities develop in liquid under long-term high voltage application. The use of the high-sensitivity CCD camera as optical detector makes it possible to capture the weak Kerr effect in high voltage stressed transformer oil. The first part of this thesis is to demonstrate the reliability and evaluate the sensitivity of the measurements for various cases with identical electrodes under pulsed excitation with insignificant flow effects. After the validation and optimization of the experimental setup, measurements are taken to record the time evolution of electric field distributions in transformer oil stressed by high voltage pulses, from which the dynamics of space charge development can be obtained. Correlation between space charge distribution pattern and impulse breakdown voltage is examined. Hypothetically, bipolar homo-charge injection with reduced electric field at both electrodes may allow higher voltage operation without insulation failure, since electrical breakdown usually initiates at the electrode-dielectric interfaces. It is shown that the hypothesis is testable and correct only under specific circumstances. Besides, fractal-like kinetics for electrode charge injection is identified from the measurement data, which enriches the knowledge on ionic conduction in liquids by offering an experimentally-determined boundary condition to the numerical model. Physical mechanisms based on formative steps of adsorption-reaction-desorption reveal possible connections between geometrical characteristics of electrode surfaces and fractal-like kinetics of charge injection. The second part of this thesis focuses on the fluctuations in the detected light intensity in Kerr measurements. Up to now, within an experimentally-determined valid range of high voltage pulse duration, the strategy to reduce fluctuation has been taking multiple measurements and then averaging the results. For very short impulses, it is found that the light intensities near the rough surfaces of electrodes both fluctuate in repeated measurements and vary spatially in a single measurement. The major cause is electrostriction which brings disturbances into optical detection. The calculated spatial variation has a strong nonlinear dependence on the applied voltage, which generates a precursory indicator of the electrical breakdown initiation. This result may have potential applications in non-destructive breakdown test and inclusion detection in dielectric liquids. When the applied voltage is dc or ac, signatures of turbulent electroconvection in transformer oil are identified from the Kerr measurement data. It is found that when the applied dc voltage is high enough, compared with the results in the absence of high voltage, the optical scintillation index and image entropy exhibit substantial enhancement and reduction respectively, which are interpreted as temporal and spatial signatures of turbulence. Under low-frequency ac high voltages, spectral and correlation analyses also indicate that there exist interacting flow and charge processes in the gap. This also clarifies the meaning of dc steady state and the requirement on ac modulation frequency in Kerr measurements.
by Xuewei Zhang.
Ph. D.
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Morris, Stephen William. "Measurements of the elastic constants of a liquid crystal." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24869.
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The bend and splay elastic constants of the nematic liquid crystal octylcyanobiphenyl (8CB) are measured as a function of temperature using an electric-field-induced deformation.
The capacitance and birefringence of a sample cell, temperature controlled to 0.1mK, were simultaneously measured as a function of applied voltage. The splay constant is determined from the critical voltage at the onset of the deformation (the Freedericksz transition). The bend constant is found by fitting the data above the critical voltage to the theory of Deuling, which is derived in full. The data is also analysed in the high- and low-field limits of the theory.
The bend elastic constant displays a pretransitional divergence near the nematic-smectic A phase transition due to smectic fluctuation effects. The divergent part is fit by a power law with a critical exponent of 1.0±0.1.
The Deuling theory, which is based on the assumption of linear elasticity, shows systematic deviation from the data at high voltages at all temperatures, with the disagreement increasing rapidly as the smectic phase is approached.
This result suggests that the linear elastic theory of Dueling/ fails for large deformations and where smectic fluctuations contribute signifigantly to the bend elasticity. The failure near the smectic transition may be explainable by the quenching of smectic fluctuations by the deformation.Science, Faculty of
Physics and Astronomy, Department of
Graduate
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Chen, Pu. "The quadrilateral relation and line tension measurements in liquid-liquid-fluid systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0004/NQ41415.pdf.
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Hornsey, Richard Ian. "Factors affecting ion energy distributions in liquid metal ion sources." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236154.
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Abid, Kifah Hussain. "New modelling and measurement techniques for liquid-liquid hold-up distribution in agitated tanks." Thesis, University of Bradford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358832.
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Omer, Muhammad. "Impingement Cooling: Heat Transfer Measurement by Liquid Crystal Thermography." Thesis, Linköping University, Applied Thermodynamics and Fluid Mechanics, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-52859.
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In modern gas turbines parts of combustion chamber and turbine section are under heavy heat load, for example, the rotor inlet temperature is far higher than the melting point of the rotor blade material. These high temperatures causes thermal stresses in the material, therefore it is very important to cool the components for safe operation and to achieve desired component life. But on the other hand the cooling reduces the turbine efficiency, for that reason it is vital to understand and optimize the cooling technique.
In this project Thermochromic Liquid Crystals (TLCs) are used to measure distribution of heat transfer coefficient over a scaled up combustor liner section. TLCs change their color with the variation of temperature in a particular temperature range. The color-temperature change relation of a TLC is sharp and precise; therefore TLCs are used to measure surface temperature by painting the TLC over a test surface. This method is called Liquid Crystal Thermography (LCT). LCT is getting popular in industry due to its high-resolution results, repeatability and ease of use.
Test model in present study consists of two plates, target plate and impingement plate. Cooling of the target plate is achieved by impingement of air coming through holes in the impingement plate. The downstream surface of the impingement plate is then cooled by cross flow and re-impingement of the coolant air.
Heat transfer on the target plate is not uniform; areas under the jet which are called stagnation points have high heat transfer as compare to the areas away from the center of jet. It is almost the same situation for the impingement plate but the location of stagnation point is different. A transient technique is used to measure this non-uniform heat transfer distribution. It is assumed that the plates are semi-infinitely thick and there is no lateral heat transfer in the plates. To fulfill the assumptions a calculated time limit is followed and the test plates are made of Plexiglas which has very low thermal conductivity.
The transient technique requires a step-change in the mainstream temperature of the test section. However, in practical a delayed increase in mainstream temperature is attained. This issue is dealt by applying Duhamel’s theorem on the step-change heat transfer equation. MATLAB is used to get the Hue data of the recorded video frames and calculate the time taken for each pixel to reach a predefined surface temperature. Having all temperatures and time values the heat transfer equation is iteratively solved to get the value of heat transfer coefficient of each and every pixel of the test surface.
In total fifteen tests are conducted with different Reynolds number and different jet-to-target plate distances. It is concluded that for both the target and impingement plates, a high Reynolds number provides better overall heat transfer and increase in jet-to-target distance
decreases the overall heat transfer.
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Hanstead, Alison Rae. "Measurement of static liquid holdup at low Eotvos numbers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0034/MQ64222.pdf.
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Vayre, Sylvain. "Développement et caractérisation d’une cible active scintillante pour l’étude de la fission et étude des possibilités de calorimétrie de la fission avec le détecteur CARMEN." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112037/document.
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La désexcitation des fragments de fission reste mal comprise et les modèles théoriques ne permettent pas de prédire et d’expliquer toutes les corrélations observées dans le processus de fission. Il y a un besoin important de données simultanées sur les émissions de neutrons et de rayonnements gamma et sur l’énergie cinétique des fragments de fission. Dans ce contexte, l’utilisation d’un détecteur de fragments de fission avec le détecteur CARMEN permettrait de fournir des données contraignantes pour les modèles grâce à la mesure simultanée de la multiplicité neutronique, de l’énergie totale gamma rayonnée, de l’énergie cinétique totale des fragments et potentiellement de l’énergie totale neutron. L’objectif de ce travail de thèse a consisté à développer un détecteur de fragments de fission et à l’utiliser en association avec CARMEN pour réaliser des mesures calorimétriques de la fission. Dans un premier temps, nous avons développé un nouveau détecteur pour l’étude de la fission dont le principe est de mettre un actinide en solution dans un scintillateur organique. Des simulations Monte Carlo et différentes expériences sous faisceau de neutrons ont permis de caractériser et d’optimiser les performances de ce détecteur qui peut être utilisé comme trigger fission pour différentes mesures de sections efficaces de fission, de taux de fission spontanée ou encore comme veto fission. Dans un second temps, nous avons étudié les possibilités de mesure de l’énergie totale gamma et neutron rayonnée dans la fission avec CARMEN grâce à la caractérisation expérimentale de ses performances et à la simulation Monte Carlo et l’analyse de sa réponse « prompte » aux neutrons et aux rayonnements gammaStill, the nuclear fission process and the de-excitation of the fission fragments is not fully understood. Current theoretical models can not predict and explain correctly every experimentally observed correlations, and new correlated data upon neutron emission, gamma-ray emission and kinetic energy of the fission fragments are needed. In this context, coincident use of a fission fragment detector and the CARMEN detector would provide compelling data for these models by measuring both neutron multiplicity, total gamma-ray energy, total kinetic energy and possibly total neutron energy. The work presented here consists in developing a fission fragment detector and using it together with CARMEN in order to perform fission calorimetry measurements. Initially, we developed a new detector for fission studies whose principle is dissolving the actinide of choice into an organic liquid scintillator. Monte Carlo simulations and neutron induced experiments were used to fully characterize its performances and shown it can be used as a fission trigger for various measurements, such as fission cross section or spontaneous fission rate measurements, and used as a fission veto. The second part of this work was dedicated to the study of CARMEN’s ability to measure the total gamma-ray energy and total neutron energy released in fission. For this purpose, lab characterization of the detector’s performances and Monte Carlo simulation and analysis of its “prompt” response to neutrons and gamma-rays were performed
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Cheng, Hsiu-Wei [Verfasser], Martin [Gutachter] Stratmann, and Markus [Gutachter] Valtiner. "Probing the solid/liquid interfacial structure of ionic liquids and battery fluids by surface force measurements / Hsiu-Wei Cheng ; Gutachter: Martin Stratmann, Markus Valtiner." Bochum : Ruhr-Universität Bochum, 2017. http://d-nb.info/1133361757/34.
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Gulliksson, Robert, Filip Johansson, and Jonas Karlsson. "Vätskemätare för glas." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-298821.
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The problem we are attempting to solve is the situation that is created when the waiting staff does not know when a guest is in need of service. Our solution to this problem is to design a coaster that wirelessly communicates with a base unit. The base unit is used by the staff to track the liquid level in all of the guests’ glasses in real time. The result of the project is a prototype that is capable of demonstrating the most basic functionality of the specified system. Even though the system is technically working, there are many areas for improvement and further development in order for the prototype to be able to be released as a complete product.Det problem som vi har uppmarksammat är den situation som skapas när serveringspersonal inte vet att kunder önskar påfyllning. Vår lösning på detta är ett dryckesunderlägg som trådlöst kommunicerar med en basenhet där personalen kan läsa av samtliga underläggs status. Projektet resulterade i en prototyp som kan demonstrera den mest grundläggande funktionaliteten hos det tänka systemet. Även om systemet fungerar finns det många utvecklingsomraden och fler problem som måste lösas innan det är redo att lanseras som en färdig produkt.
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Fabritius, T. (Tapio). "Optical method for liquid sorption measurements in paper." Doctoral thesis, University of Oulu, 2007. http://urn.fi/urn:isbn:9789514284045.
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Abstract
This thesis presents an effective optical method for measuring liquid sorption into paper. From the two tested methods, based on a streak-camera and optical coherence tomography (OCT), the last-mentioned proved very promising for investigating dynamical paper-liquid interactions as spatially and temporally dependent processes.
The streak-camera measurements were performed to explore the relationship between paper properties and light migration in dry and refractive index matched paper in general. Based on streak-camera measurements, a novel procedure for determining the average refractive index of cellulose fibre tissue was also presented here. In addition, the streak camera method lent itself to paper porosity determination.
Results of the performed OCT measurements proved that liquids cannot penetrate into paper before filling the pores and pits of the paper surface. As a liquid penetrated into paper, the border between the wetted and dry area could be investigated in the depth direction. The liquid penetration velocity seemed to be slower at the beginning and end of the process. Liquid absorption into paper fibres could be investigated concurrently. For the first time, the location and moment of structural changes in paper could be determined during wetting, and the effect of three different coexistent subprocesses related to paper wetting could be detected. OCT only fell short of detecting the effect of liquid migration along fibres.
Despite the limitations of the utilized method (resolution, probing depth and depth scanning rate), the obtained OCT measurement results are very promising for the development of an effective paper wetting measurement device for industrial applications. Even if this thesis focused on paper wetting, it is reasonable to assert that the presented ideas and obtained results have more general value in terms of explaining liquid penetration into porous structures and offer an alternative method of evaluating that process.
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Papavassiliou, John. "Measurements of cellular structure in liquid aerosol detonation." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60571.
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Detonations in decane aerosol-oxygen mixtures were studied with the aim being to contribute to the understanding of the mechanisms of propagation of the detonation front. The decane aerosol, of about 5 $ mu$m droplet size, is generated by an ultrasonic nebulizer and remains in the liquid phase prior to ignition. A vertical detonation tube 64 mm in diameter and 3 m long was used. Ignition of the mixtures was attained using an exploding wire (120 Joules stored energy) or a solid explosive detonator. Comparison of the experimentally measured detonation velocity and pressure to the theoretical Chapman-Jouguet velocity and pressure indicates the existence of a self-sustained heterogeneous detonation. Cellular structure was recorded on soot covered metallic foils, indicating a three-dimensional detonation structure similar to gas phase detonations. The physical processes of breakup, heat transfer, evaporation, and mixing present in the heterogeneous medium were eliminated by heating of the mixtures to the vapor phase. Comparison of cell size for the same mixtures in the heterogeneous liquid phase and in the homogeneous vapor phase reveals that aerosol detonations possess physical processes that increase the length scale of the detonation. Furthermore, the measurements of cellular structure obtained experimentally are compared with the computed results determined using a chemical kinetic detonation model and the length scales of the mixtures in the vapor phase are found to be in good agreement with the computed results.
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Sidney, John Kenneth. "Cross-correlation flow measurements in liquid-gas mixtures." Thesis, Teesside University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328785.
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Hughes-Davies, T. T. "An X-ray reflectometer for the study of liquid surfaces." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234985.
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Wilson, David James. "Diffraction measurements of crystalline morphology in thermotropic random copolyesters." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241169.
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