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1
Ash, Dean Christopher. "The liquid droplet quartz crystal microbalance micro viscometer." Thesis, Lancaster University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423557.
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Presented here is a novel use of the Quartz Crystal Microbalance QCM as a droplet micro-viscometer. The droplet micro-viscometer is so named as it requires only a micro litre of liquid in the form of a droplet in order to determine the liquid viscosity. The crystal operates using the inverse piezoelectric effect and the droplet is applied to one electrode of the freely oscillating crystal. Loading the crystal surface this way produces a frequency change .11 in the oscillating frequency of the crystal, as a function of the liquid viscosity. Monitoring of this frequency allows for determination of the liquid viscosity. Jointly sponsored by the EPSRC and British Nuclear Fuels plc, this research was proposed by BNFL as a way of maintaining tighter control on an important parameter of a solvent extraction nuclear fuel reprocessing process. Research in this area started with the assessment of the QCM to give meaningful results for viscosity from a single droplet of liquid, initially, alcohols whose physical parameters were well documented. Encouraging results prompted further experimentation with tri-n-butyl phosphate or TBP, diluted with odourless kerosene, OK. Wider potential was realised and motor oils and fuel oils were targeted as a potential use for this technology. Motor oil as viscosity is a first indicator of the oil condition/quality and fuel oils specifically in the identification of red diesel when diluted in white diesel.As this technology was intended for use as a sensor it was important, for financial reasons, that the sensor element in contact with the liquid could be cleaned thoroughly enough to allow re-use without degradation of the results produced. A cleaning regime is covered in this work showing that cleaning is feasible but has limits in the amount of times this can successfully be performed before a replacement QCM is required. Some simple experiments on samples of whisky were performed in pursuit of a use in the foodstuffs industry with the institute of food research. These show a possible method of identification but no further work was done on this as other research demanded the time. Results show that the QCM results clearly demonstrate the use of a liquid droplet on one face does produce meaningful results with relation to the viscosity of the liquid. Various diJutions ofTBP and OK are distinguishable from each other as are various dilutions of red diesel in white diesel and oils of varying viscosity. The droplet QCM micro viscometer has the advantage over most other methods of viscometry not in its accuracy of absolute viscosity measurement but in the very small amount of sample liquid needed for test. This is a very desirable factor in situations where repeat sampling of a fixed volume of liquid is required as the samples taken need not significantly reduce the sample volume.
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Ronaldson, Kelly Anne. "Mathematical modelling of MEMS viscometers and densitometers." Thesis, University of Southampton, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440421.
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Abid, Saeid. "Evaluation of a falling body-type viscometer at high pressure." Thesis, University of Strathclyde, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.510719.
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Xu, Z. "Development of a process control rheometer." Thesis, University of Strathclyde, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382481.
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Lee-Yow, Niko. "Optically Clear Biomicroviscometer with Modular Geometry Using Disposable PDMS Chips." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37091.
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We have designed and fabricated a biomicroviscometer platform for measurement of microflows of biological fluids. The biomicroviscometer combines an optically clear biocompatible polydimethylsiloxane (PDMS) channel with on-chip integrated microfluidic differential pressure sensors and capabilities of modular channel geometries. This setup allows for a direct measurement of the change in pressure and flow rate, increasing the overall accuracy of the measurement of viscosity and optical observation. We present an introduction of this combined method of measurement with different channel dimensions, using Newtonian and non Newtonian fluids, and the corresponding calculations. This measurement technique has potential applications in measuring rheological properties at the micro level to further blood disease analysis, and lab-on-a-chip fabrication and analysis.
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Chan, Paul Wing Hung. "In-situ viscosity measurement." Thesis, University of Bristol, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341507.
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SANTOS, WALTER M. "Aplicacao da viscosimetria na deteccao de especiarias irradiadas." reponame:Repositório Institucional do IPEN, 1994. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10358.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
8
Alanazi, Hamdan Noman. "Characterization of Elastin-Like Polypeptides Using Viscometry." Cleveland State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=csu1311026986.
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Persson, Sylvi. "Erythrocyte deformability studies by viscometry and filtrometry." Lund : Dept. of Medicine, University Hospital of Lund, Lund University, 1994. http://catalog.hathitrust.org/api/volumes/oclc/39207611.html.
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Slatter, Paul Thomas. "The rheological characterisation of non- Newtonian slurries using a novel balanced beam tube viscometer." Master's thesis, University of Cape Town, 1986. http://hdl.handle.net/11427/19914.
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The novel Balanced Beam Tube Viscometer (BBTV), developed at the University of Cape Town, has been further developed and refined. Extensive work has been done in the following areas: (i) The effective length of the BBTV tubes. (ii) Interpretation of the data obtained using the BBTV in both the laminar and turbulent flow regimes. (iii) Comparison with the rotary type viscometer. Kaolin clay and uranium tailings slimes slurries of different particle size range and concentration have been successfully characterised by yield- pseudoplastic rheologies using the BBTV. The BBTV is in fact a miniature pipeline and it has been shown that it is capable of producing valid turbulent flow data and indicating the laminar/turbulent transition region in the two tube sizes .
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DuMond, Todd O. (Todd Oliver) 1977. "The feasibility of using viscometers and flowmeters in an oilwell environment." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/88890.
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Hird, Lee D. "Analysis of the flow field between two eccentric rotating cylinders in the presence of a slotted sleeve." Curtin University of Technology, School of Mathematics and Statistics, 1997. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=11104.
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Overend et al [68] designed a viscometer to measure the viscosity of slurries that have a tendency to settle. This viscometer consists of a rotating ribbed rotor surrounded by a stationary slotted sleeve; this system is then placed eccentrically within an inclined rotating bowl. It, is claimed that this overcomes most of the difficulties encountered when attempting to obtain accurate measurements for these types of mixtures. If the mixture being sheared within the annulus does not represent the true composition of the slurry being, tested then the results are expected to be inaccurate. The presence of sediment at the bottom of the rotor or the formation of large masses of particles within the flow domain will affect the accuracy of the measurements obtained. This dissertation studies the amount of flow through the slotted sleeve and the region, or regions, of low shear rate within the flow domain. Assuming that end-effects are unimportant and that the slurries can be replaced by a single-phase fluid, three two-dimensional models are proposed. These models are designed to capture the large-slot construction of the sleeve and the, approximate, non-Newtonian behaviour of the slurries. The first two models solve analytically (using a regular perturbation scheme) and numerically (using a finite volume method) the moderate-and large-Reynolds-number flow, and the third model uses a finite volume method to study the flow patterns developed by pseudoplastic fluids. The results show that the mixing of the slurry is expected to be enhanced by moving the concentric system (i.e., the rotor and the slotted sleeve) close to the rotating bowl and using low to moderate speeds for the rotor and bowl. In addition, when the cylinders rotate in the same directions, two (counter-rotating) eddies are present within the flow domain; whereas, only one eddy (rotating counter-clockwise) is ++present when the cylinders rotate in opposite directions. The presence of eddies in the former situation inhibits the flow through the sleeve; while, for moderate rotorspeeds, the flow through the sleeve is enhanced in the latter. When the slurry assumed pseudoplastic, we observe a region of low shear rate located near the dividing streamline present within the flow field. The distribution of shear rate within the flow field is shown to be affected by factors such as the rate of diffusion of the apparent viscosity and the value of the power law index. Therefore, this study suggests that for certain types of slurries, concentrations of particles exist within the domain and that the mixing of slurries can be impeded by the presence of eddies within the main flow field.
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Kambow, Sumit H. "Characterization of Elastin-like Polypeptide Micelles Using Capillary Viscometry." Cleveland State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=csu1337605892.
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Scott, Matthew. "The modeling of blood rheology in small vessels." Thesis, University of Waterloo, 2005. http://hdl.handle.net/10012/1149.
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Blood is a dense suspension of flexible red blood cells. In response to a background flow, these cells distribute themselves non-uniformly throughout the vessel. As a result, material properties that are well defined in homogeneous fluids, such as viscosity, are no longer so, and depend upon the flow geometry along with the particle properties. Using a simple model that accounts for the steady-state particle distribution in vessel flow, we derive an expression for the effective viscosity of blood and the suspension flow velocity field in a pressure-driven tube flow. We derive the steady-state particle distribution from a conservation equation with convective flux arising from particle deformation in the flow. We then relate the particle microstructure to the overall flow through a generalized Newtonian stress-tensor, with the particle volume fraction appearing in the expression for the local viscosity. Comparing with experimental data, we show that the model quantitatively reproduces the observed rheology of blood in tube flow.
We reconsider the problem in an alternate geometry corresponding to the flow between two concentric cylinders. The steady-state particle distribution, suspension velocity field and the measured effective viscosity are all very different from their counterparts in tube flow, casting serious doubt upon the practice of using data from a Couette viscometer to parameterize constitutive models applied to vascular blood flow.
Finally, we calculate the effect of random fluctuations in the particle velocity on the averaged behaviour of the particle conservation equation. Using a smoothing method for linear stochastic differential equations, we derive a correction to the free Einstein-Stokes diffusion coeffcient that is due to the interaction of the particles with their neighbours.
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Ritwik. "Measuring the viscous flow behaviour of molten metals under shear." Thesis, Brunel University, 2012. http://bura.brunel.ac.uk/handle/2438/6686.
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The flow behaviour of liquid metals (Sn, Pb and Sn-Pb eutectic) under different shearing conditions is investigated. Experiments were performed with two designs of concentric cylinder viscometers: rotating the inner cylinder (Searle) and rotating the outer cylinder (Couette). The latter technique is uncommon and the equipment was optimised with standard oils. The flow behaviour for the metals differs in the two systems. The curves of 'apparent' viscosity versus shear rate may be divided into two regimes: I. At lower shear rates (<200 s-1): a reduction of 'apparent' viscosity with shear was observed with both viscometers. It is suggested that the high density and high surface tension of the metals and eccentricity between the cylinders at low shear rates, leads to instabilities. Results at low shear rates were therefore discarded and further detailed analysis would be required for a fuller understanding of this behaviour. II. At higher shear rates: a steady, shear-independent behaviour of 'apparent' viscosity with shear rate is observed in the Couette system (upto 600 s-1) whereas in the Searle system the 'apparent' viscosity increases with shear rate (upto 2600 s-1). From hydrodynamic theory about Newtonian fluids, it is suggested that in the Searle type viscometer, the fluid is unstable and Taylor vortices are expected at low shear rates (~80 s-1). This gives rise to an increase in the 'apparent' viscosity with shear rate. Whereas, in the Couette type, the flow is more stable, resulting in a steady 'apparent' viscosity. This interpretation is consistent with liquid metals behaving as Newtonian fluids, but further research is required to confirm this. The author suggests further experiments, with the prime one being the investigation of the fluid with counter and co-rotation of the cylinders in order to observe more complex flows. The results are expected to have implications in the modelling of flow for liquid metal processes, especially the initiation of Taylor vortices under the unstable flow conditions produced by rotating the inner cylinder.
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Bhatia, Rupesh. "Effect of molecular mass, concentration and temperature on the rheological properties of non-newtonian aqueous polymeric solutions." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1313765879.
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Wichchukit, Sukanya. "Rheological property studies of confectionary products using conventional viscometries and tomographic viscometry /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
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Newkirk, Matthew Stanton. "Design and Development of a High-Temperature High-Pressure Rolling Ball Viscometer/Densimeter and Evaluation of Star Polymer-Solvent Mixtures." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4654.
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Modern automotive applications such as transmission clutch plates, combustion chambers, diesel fuel injector tips, and axle gears and friction plates operate at temperatures that can exceed 250°C and pressures of 40,000 psia. Industrial practice is to add homopolymers and copolymers to base oils to modify bulk fluid viscosity and frictional properties for these demanding applications. However, designing polymeric additives for lubricants and predicting their performance is limited by the lack of available high-temperature high-pressure (HTHP) viscosity and density data needed to test contemporary lubricity models. Thus, a major objective of this thesis is the design, development, and commissioning of a rolling ball viscometer/densitometer (RBVD) capable of simultaneously determining fluid densities and viscosities at temperatures in excess of 250°C and pressures of 40,000 psia. Resulting data may then be generated to directly address the fundamental need for lubricant property data at these HTHP conditions. The design and development of the RBVD is described in detail to highlight the design iterations and modifications utilized to ensure robust operation at extreme conditions. Three significant and novel features of this RBVD apparatus that distinguish and differentiate it from other apparatus of this type are: (1) specially designed metal-to-metal and sapphire-to-metal seated surfaces capable of eliminating temperature- and chemically-sensitive elastomeric seals; (2) use of a bellows piston to eliminate significant temperature and operational constraints; and (3) incorporation of a linear variable differential transducer (LVDT) to simultaneously permit determination of solution density and viscosity. A detailed analysis of initial accumulated uncertainty for the experimental viscosity and density techniques revealed the need for key RBVD modifications. Final data are presented showing that the RBVD is capable of measuring viscosities with an accuracy of ± 2 to 3 percent and densities to ± 0.7 percent, including at the extreme operating conditions targeted.
A second objective of this thesis is the measurement of HTHP viscosities of star polymer-solvent mixtures to determine the impact of star polymer architecture on solution viscosity at extreme conditions similar to those that might be experienced in automotive applications. This objective is motivated by current challenges facing industry to identify polymeric additives that can be added to base oils to improve fuel economy and allow for the implementation of novel hardware technology that relies on enhanced lubricant properties. Relative to linear polymers, the unique architecture of star polymers enhances polymer solubility in base oils while having a more favorable impact on viscosity and density properties over a wide range of temperatures and pressures. Data are presented for an industrially-relevant star polymer in octane to assess the impact of the star configuration on solvent viscosity at extreme conditions. The star polymer used in this instance consists of an ethylene glycol dimethacrylate (EGDMA) core with poly(lauryl methacrylate-co-methyl methacrylate) (LMA-MMA) arms. The star polymer has a total weight averaged molecular weight (Mw) and Mw of each arm of 575,000, and 45,000, respectively. The copolymer arms of the star polymer have an LMA-to-MMA mole ratio of 0.6.
The results of further viscosity studies are presented for a model system of well-characterized commercially available narrow polydispersity index (PDI) star polystyrenes (PS) in toluene. Each PS is evaluated at a two percent by weight concentration in toluene to evaluate the effect of arm molecular weigh on viscosity. Each three-arm star polymer has arm and total molecular weights ([arm Mw] total star Mw) of ([15,400] 41,200), ([36,000] 97,600), and ([108,000] 305,000). In this instance, the viscosity of toluene increased by more than a factor of three for the star with the highest Mw arms.
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Eren, Tuna. "Foam Chacrization Effects Of Bubble Size And Texture." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605373/index.pdf.
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Foam is one of the most frequently used multiphase fluids in underbalanced drilling operations because of its high carrying capacity of cuttings, compressibility property, formation fluid influx handling, etc. Foam rheology has been studied for many years. Researchers tried to explain foam behaviour by using conventional methods, i.e., determining rheological parameters of pre-defined rheological models like Power law, Bingham Plastic etc., as a function of gas ratio. However, it is known that bubble size and texture of the foam is also effective on foam behaviour. When foam is generated by using different foaming agents, even if the gas ratio is constant, different rheological parameters are observed. Therefore a more general foam characterization method that uses the bubble size and texture of foam is required. Improvements on image analysis, and computer technology allow monitoring the bubble size and texture of foam bubbles.
A more comprehensive model of foam rheology definition in which the bubble size, and texture effects of the foam body is developed. Three different analysis methodologies are introducedi) Generalized volume equalized approach, ii) Generalized volume equalized approach and image processing data, and iii) Image processing data only. The necessary information including the rheological information and image data is acquired from the experimental set-up developed for this study. It has been observed that, the pressure losses could be predicted as a function of bubble size, circularity and general rheological parameters, in &
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20 % certainty limit. It is also observed that using only the image information is possible to characterize the foam in an accurate and fast manner.
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Santos, Fabrício Bassani dos. "Influência do C3A em pastas de cimento portland = avaliação das propriedade reológicas." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/258504.
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Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e UrbanismoMade available in DSpace on 2018-08-17T11:28:28Z (GMT). No. of bitstreams: 1 Santos_FabricioBassanidos_M.pdf: 870223 bytes, checksum: 8af2408dfd741b81353a11d68bfe345e (MD5) Previous issue date: 2004
Resumo: A produção de concretos com elevado desempenho quanto a fluidez, propriedades reológicas e durabilidade, demanda o conhecimento das características físico-quimicas dos cimentos, intervenientes no desempenho dos mesmos. O presente trabalho estuda a influência do teor do C3A, tendo por objetivo contribuir para a compreensão dos fatores que deteiroinam o comportamento reológico das pastas de cimento. Foram selecionados três cimentos nacionais com diferentes teores de C3A e com mínimos teores de adições presentes. Efetuou-se a composição de um cimento e uma escória de alto-forao, obtendo-se também três diferentes teores de C3A. Estes materiais foram moídos em laboratório para equalização das suas áreas específicas. A avaliação do comportamento reológico embasou-se na determinação da viscosidade das pastas através de ensaios com um viscosímetro rotativo e, indiretamente, correlacionando à área de espalhamento obtida pelo ensaio do abatimento do mini-tronco de cone. O método do abatimento do mini-tronco de cone não se mostrou satisfatório para a avaliação do comportamento reológico dos materiais estudados. Através dos resultados obtidos com o viscosímetro rotativo foi possível determinar a viscosidade aparente, em função do tempo - as quais indicaram um comportamento reológico característico para as diferentes amostras e misturas avaliadas.
Abstract: The production of high performance concrete with special rheologic properties, fluidity and durability, demands the knowledge of physical and chemical characteristics of the used cement. The herein research studies the C3A influence on cement pastes, in order to add knowledge to all the aspects that can contribute to its rheologic behavior and, consequently, to mortars and concretes. It was select three Brazilian cements with different amounts of C3A and minimum additions to the clinker. It was made a composition of the cement and blast furnace granulated slag in order to obtain three different amounts of C3A. These materials were grind to have the same specific surface. The Theological behavior was studied through determination of the viscosity of the cement pastes, and correlating it with the spread surface obtained by the Kantro test. This test method was not efficient in showing the real rheologic behavior of the studied materials. It was possible to determinate the apparent viscosity with time through the use of a viscometer device, which has shown a peculiar rheological behavior to the different specimens and mixtures studied.
Mestrado
Edificações
Mestre em Engenharia Civil
21
Bailey, Christopher Allen. "Structure and Rheology of Some Bent Core Liquid Crystals." Kent State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=kent1216229977.
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Dickmann, James Scott. "Volumetric Properties and Viscosity of Fluid Mixtures at High Pressures: Lubricants and Ionic Liquids." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/90219.
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The present thesis explores the volumetric and transport properties of complex fluid mixtures under pressure in order to develop a better, more holistic understanding of the relationship between the volumetric properties, derived thermodynamic properties, and viscosity. To accomplish this broad objective, two different categories of fluid mixtures were examined using a combination of experimental data and models. These included base oils and their mixtures with polymeric additives, used in lubricants and ionic liquids, with cosolvent addition, for use in biomass and polymer processing. Experimental density data were collected using a variable-volume view-cell at pressures up to 40 MPa and temperatures up to 398 K. A unique high pressure rotational viscometer was developed to study the effect of pressure, temperature, and shear rate on viscosity while also allowing for the simultaneous examination of phase behavior. Viscosity data were collected at pressures up to 40 MPa, temperatures up to 373 K, and shear rates up to 1270 s-1. Experimental density and viscosity data were fit to a pair of coupled model equations, the Sanchez-Lacombe equation of state and the free volume theory respectively. From density, derived thermodynamic properties, namely isothermal compressibility, isobaric thermal expansion coefficient, and internal pressure, were calculated. By generating these models, viscosity could be viewed in terms of density, allowing for a direct link with thermodynamic properties.
In the first part of the study, the effect of composition on density, thermodynamic properties, and viscosity was examined for base oils used in automotive lubricants. Six different base oils, four mineral oils and two synthetic oils, were studied to develop a better understanding on how the thermodynamic properties, particularly isothermal compressibility and internal pressure, vary with the concentration of cyclic molecules in the oil stock. Isothermal compressibility was found to decrease with cycloalkane content, while internal pressure increased. Additionally, the effect of two different polymeric additives on the volumetric properties and viscosity of a base oil composed of poly(α olefins) was examined. Both additives are polymethacrylate based, one with amine functionality, and are used as viscosity index modifiers in engine oils and automatic transmission fluids. The polymer with amine functionality was found to have a significant effect on internal pressure, seen as a large drop at high polymer concentration (7 mass percent), due to the addition of repulsive intermolecular interactions.
In the second part of the study, six ionic liquids with the 1-alkyl-3-methylimidazolium cation and their mixtures with ethanol were examined. Two anions were used, chloride and acetate. The effect of ethanol addition on the derived thermodynamic properties and viscosity was studied in terms of chain length of the alkyl group on the cation. In addition, a method of estimating Hildebrand solubility parameter was employed, allowing for solubility parameter to be put in terms of pressure, temperature, and composition. The effect of cosolvent addition on the thermodynamic properties was changed by the length of the alkyl group on the cation. As the cation became bulkier, anion-cation interactions weakened, allowing for an increase in the anion-cosolvent interactions.Doctor of Philosophy
The present thesis aims to understand both the density and viscosity of various fluid mixtures at high pressures and temperatures through both experiments and modeling. By studying these properties simultaneously, a more holistic view of a fluid can be developed to predict its usefulness for a specific application. This is especially important in the case of fluid mixtures, where, in addition to temperature and pressure, composition needs to be taken into account. To accomplish the experimental portion of this work, a new high pressure rotational viscometer was developed to measure viscosity as a function of temperature and pressure in conjunction with a preexisting technique for measuring density. This experimental data was used to create models, allowing for a better understanding of the effect of temperature, pressure, and composition on both density and viscosity along with certain thermodynamic properties. In the first part of the study, oils and additives used to make lubricants with automotive applications, such as engine oils and automatic transmission fluids, were studied. By studying the properties of these mixtures under pressure, a better understanding of how properties key to lubricant effectiveness are related to temperature, pressure, and composition can be developed. In the second part of the study, ionic liquids, salts with melting points below 100oC, and their mixtures with ethanol were studied. Ionic liquids have unique properties and have been studied for use in batteries, polymer processing, biomass processing, and gas capture. Due to the wide range of potential ionic liquids with various properties that can be made, these salts have been described as tailorable solvents. By adding an additional solvent, the resulting mixture can be tuned through temperature, pressure, and composition. Using the set of tools employed in the present work, important properties for process design were calculated. In particular, the Hildebrand solubility parameter was estimated as a function of temperature, pressure, and composition. The solubility parameter is a useful tool in predicting whether or not a material will dissolve in the solvent of choice.
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黃柏林 and Pat-lam Patrick Wong. "An investigation of the rheological behaviour of lubricants using the optical impact viscometry technique." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1990. http://hub.hku.hk/bib/B31232036.
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Wong, Pat-lam Patrick. "An investigation of the rheological behaviour of lubricants using the optical impact viscometry technique /." [Hong Kong] : University of Hong Kong, 1990. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12742107.
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Williams, R. H. "A laboratory viscometry system for the measurement of the rheological properties of silicate melts." Thesis, Lancaster University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371951.
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Lohmander, Sven. "The influence of particle shape of coating pigments on their packing ability and on the flow properties of coating colours." Doctoral thesis, KTH, Pulp and Paper Technology, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3044.
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The influence of particle shape of coating pigments on theirpacking ability and on the flow properties of coating colourshas been investigated. The particle shapes considered werespherical, flaky and acicular (needle-shaped). In the case ofsuspensions containing monodisperse spherical polystyreneparticles, a concentration gradient appeared in the filter cakeforming during filtration under static conditions. Such agradient, monitoredby non-destructive magnetic resonanceimaging (MRI), is not accounted for in the traditionalfiltration theory used in coating technology. Good agreementwas found between a literature model describing filtrationthrough a compressible filter cake and the concentrationgradients measured by MRI. According to this model, the scaledconcentration gradient was the same at all times.
For flaky (mainly kaolin) and acicular (aragonite)particles, a rapid method was evaluated to estimate a shapefactor of the pigment particle. Generalised mathematical modelsof oblate and prolate spheroids were applied to reduce thethree geometrical dimensions of the particle to two, the majoraxis and the minor axis. The shape factor, which is mass-based,was derived from a comparison between the results obtained bytwo different size-assessment instruments, viz. the Sedigraphand an instrument using light scattering. This yields a shapefactor distribution as a function of equivalent sphericalparticle size, but the results are uncertain for small particlediameters, below 0.2 µm. Good agreement was obtainedbetween the shape factor and a mass-based aspect ratio obtainedby image analysis, but the rapid method is generally moreaccurate for flaky than for acicular particles.
Results obtained by capillary viscometry showed that therewas a relationship between the viscosity at high shear rates(>105s-1) and the shape factor, but that it was notsufficient to use the median value of the shape factor toachieve proper information. A more complete evaluation requiresknowledge of the shape factor distribution, which is also givenin part by the method mentioned above. However, a large medianshape factor was related to a high high-shear viscosity.Non-Newtonian entrance pressure losses were sometimessignificant in capillary viscometry, indicating that it wasinappropriate to measure the shear viscosity with only onecapillary. Such effects were however relatively much morepronounced in slit die viscometry, especially in the case ofacicular particles, where the aspect ratio was a crucialparameter. The influence of the shape factor of kaolinparticles on the non-Newtonian entrance pressure losses over aslit die was surprisingly small. The high-shear viscosity ofcoating suspensions based on different pigments correlated withthe median pore size of the corresponding coating layer ratherthan with the porosity.
Keywords: Aspect ratio, capillary viscometry, coatingcolour, filtration, particle packing, pigment, pore structure,rheology, shape factor, slit die viscometry, spheroid.
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Schäfer, Michael [Verfasser], Roland [Akademischer Betreuer] Span, and Markus [Akademischer Betreuer] Richter. "Improvements to two viscometers based on a magnetic suspension coupling and measurements on carbon dioxide / Michael Schäfer. Gutachter: Roland Span ; Markus Richter." Bochum : Ruhr-Universität Bochum, 2016. http://d-nb.info/1082425451/34.
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Mazzotta, Francesco. "Studio reologico avanzato di bitumi modificati ed additivati:proposta di una nuova procedura di aging." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/4257/.
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Le problematiche ambientali e socio – economiche legate alla costruzione di nuove infrastrutture viarie, impongono la progettazione e costruzione di strade che combinino ad elevati standard prestazionali, la riduzione dell’impatto ambientale in fase realizzativa e manutentiva. Quanto detto avvalora il crescente utilizzo di materiali bituminosi modificati con polimeri ed additivati con cere. I primi conferiscono alla miscela maggiore elastoplasticità, incrementandone la durabilità e la resistenza a fatica. Nei secondi la presenza del materiale paraffinico contribuisce a ridurre la viscosità del bitume, il che consente il notevole abbassamento della temperatura di produzione e stesa della miscela. Numerosi studi inoltre hanno dimostrato che le caratteristiche meccaniche della pavimentazione sono fortemente influenzate dal grado di ossidazione delle componenti organiche del bitume, ovvero dal fenomeno dell’invecchiamento o aging. Risulta pertanto fondamentale affiancare allo studio reologico del bitume, prove di simulazione dell’ invecchiamento nel breve e lungo termine. Nel corso della seguente ricerca si provvederà pertanto ad analizzare leganti modificati ed additivati secondo la teoria della viscoelasticità, simulando le reali condizioni di carico ed invecchiamento alle quali il bitume è sottoposto. Tutte le prove di caratterizzazione reologica avanzata prevederanno l’utilizzo del DSR (Dynamic Shear Rheometer) in varie configurazioni di prova e si simulerà l’invecchiamento a breve termine mediante RTFOT (Rolling thin film oven test). Si proporrà inoltre una nuova procedura di aging invecchiando il bitume alla temperatura di equiviscosità o Twork , ovvero a quel valore della temperatura tale per cui, in fase di messa in opera, si avrà una distribuzione molecolare omogenea del modificante all’interno del bitume. Verranno quindi effettuate ulteriori prove reologiche sui leganti invecchiati a tale temperatura. Si darà infine supporto ai risultati della ricerca effettuando prove chimiche con la tecnica analitica FTIR (Fourier Transform Infrared Spectroscopy), analizzando i cambiamenti molecolari avvenuti nel bitume a seguito dell’aggiunta del modificante e dell’invecchiamento.
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Rowane, Aaron J. "High-Temperature, High-Pressure Viscosities and Densities of Toluene." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4188.
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High-temperature, high-pressure (HTHP) conditions are exemplified in ultra-deep petroleum reservoirs and can be exhibited within diesel engines. Accurate pure component hydrocarbon data is essential in understanding the overall behavior of petroleum and diesel fuel at these conditions. The present study focuses on the HTHP properties of toluene since this hydrocarbon is frequently used to increase the octane rating of gasoline and toluene occurs naturally in crude oil. In this thesis experimental densities and viscosity are presented to 535 K and 300 MPa extending the database of toluene viscosity data to higher temperature than previous studies. The data is correlated to a Tait-like equation and a Padѐ approximate in conjunction with a single mapping of the isotherms. Free-volume theory and a superposition of the viscosity in relation to the Leonnard-Jones repulsive force are both used to model the toluene viscosity data. It was found that the data are in good agreement with the available literature data.
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Billberg, Peter. "Form pressure generated by self-compacting concrete : influence of thixotropy and structural behaviour at rest." Doctoral thesis, Stockholm : Division of Concrete Structures, Royal Institute of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4144.
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Kandil, Mohamed E. "The development of a vibrating wire viscometer and a microwave cavity resonator for the measurement of viscosity, dew points, density, and liquid volume fraction at high temperature and pressure." Thesis, University of Canterbury. Chemical and Process Engineering, 2005. http://hdl.handle.net/10092/1070.
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This thesis describes the development and testing of two apparatuses; a vibrating wire viscometer to measure the viscosity of fluids over a wide range of temperature and pressure; and a microwave cavity resonator to measure dew points, gas phase densities, and liquid drop out volumes. Viscosity and density of downhole fluids are very important properties as their values can determine the economic viability of a petroleum reservoir. A vibrating wire viscometer has been developed with an electrically insulating tensioning mechanism. It has been used with two wires, of diameters (0.05 and 0.150) mm, to measure the viscosity of methylbenzene and two reference fluids with viscosities of (10 and 100) mPa·s at T = 298 K and p = 0.1 MPa, at temperatures in the range (298 to 373) K and pressures up to 40 MPa, where the viscosity covers the range (0.3 to 100) mPa·s, with a standard uncertainty < 0.6 %. The results differ from literature values by < ±1 %. The results demonstrate that increasing the wire diameter increases the upper operating viscosity range of the vibrating wire viscometer, a result anticipated from the working equations. For the microwave cavity resonator, the method is based on the measurements of the resonance frequency of the lowest order inductive-capacitance mode. The apparatus is capable of operating at temperatures up to 473 K and pressures below 20 MPa. This instrument has been used to measure the dew pressures of {0.4026CH4 + 0.5974C3H8} at a temperature range from 315 K up to the cricondentherm ˜ 340 K. The measured dew pressures differ by less than 0.5 % from values obtained by interpolation of those reported in the literature, which were determined from measurements with experimental techniques that have quite different potential sources of systematic error than the radio-frequency resonator used here. Dew pressures estimated from both NIST 14 and the Peng-Robinson equation of state lie within < ±1 % of the present results at temperature between (315 and 337) K while predictions obtained from the Soave-Redlich-Kwong cubic equation of state deviate from our results by 0.4 % at T = 315 K and these differences increase smoothly with increasing temperature to be -2.4 % at T = 337 K. Densities derived from dielectric permittivity measurements in the gas phase lie within < 0.6 % of the values calculated from the Soave-Redlich-Kwong cubic equation of state and about 1 % from values obtained with the Harvey and Prausnitz correlation based on a mixture reduced density. The calculations with Kiselev and Ely parametric crossover equation of state (based on Patel-Teja EOS) gave deviations < 0.7 %. Liquid volume fractions, in the 2-phase region, were measured from (0.5 to 7) cm3 in a total volume of about 50 cm3 at different isochors. The measured liquid volume fractions differ from values obtained with the Soave-Redlich-Kwong cubic equation of state by between 0 and 3 % at T < 326 K and about 8 % on approach to the critical region. The large deviations observed in the critical region were anticipated because of the known poor performance of the cubic equations of state with regard to the calculation of the liquid density in the vicinity of the critical temperature.
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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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Badiane, Doudou. "Simulation numérique et étude expérimentale d'un viscosimètre à principe vibrant." Thesis, Orléans, 2012. http://www.theses.fr/2012ORLE2057/document.
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La connaissance de la viscosité est un défi majeur dans les technologies de pointe (biomédical, pétrochimie, imprimerie, cosmétique, agroalimentaire, etc). Cette étude présente un capteur de viscosité qui exploite la vibration transversale forcée d’une poutre mince. L’amortissement induit par le fluide permet d’évaluer sa viscosité et sa masse volumique par la seule connaissance des caractéristiques à la résonance de la poutre (amplitude et fréquence). Cette mesure est réalisée par un circuit électromagnétique. Dans ce travail, la simulation numérique et l’étude expérimentale du viscosimètre sont réalisées en vue de mieux cerner les paramètres influençant le fonctionnement du capteur. Les différentes investigations menées dans ce travail sont d’une grande importance pour l’optimisation du viscosimètre d’une part. D’autre part, c’est une contribution à l’ensemble des études qui traitent de l’aspect du couplage fluide-structure-électromagnétismeKnowing the viscosity becomes increasingly a major challenge in leading-edge technologies (biomedical, petrochemical, printing, cosmetic, food industry, etc). This study presents a viscosity sensor based on a thin beam immersed in a newtonian fluid and subjected to transverse vibrations due to an electromechanical excitation system. The damped vibration can be used to evaluate the fluid viscosity and density by measuring the beam’s resonance characteristics (amplitude, frequency). This measurement is done by an electromagnetic feedback circuit. In this work, numerical model and experimental studies of the vibrating viscometer are conducted to better understand the influencing factors of the sensor’s operation. The different investigations carried out in this work are of great importance for the viscometer optimization on one hand. On the other hand, it’s a contribution to all studies dealing with the aspect of fluid-structure-electromagnetism coupling
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Glombová, Pavla. "Stanovení viskozity pro různé typy splaškových vod." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227747.
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The aim of this diploma thesis is a description of viscosity as a physical characteristic of liquids, next a description of projecting different types of sewer systems (pressure sewer system, vacuum sewer system and gravity sewer system). There was a range of density and viscosity of wastewater experimentally determined. These values were compared with ordinary values used in practice. The practical part of this work consists of sampling wastewater from different types of sewer systems and various localities. Chemical-biological analysis was realized on those samples with defined density, then dynamic viscosity was measured by the rotary viscometer for various temperatures. Measured data are evaluated. Finally, a calculation related to the design of sewers was made.
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Macijauskas, Mindaugas. "Cemento atmainos ir cheminių įmaišų įtaka tešlos reologinėms savybėms." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140609_140245-06973.
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Baigiamojo magistro darbo tikslas – ištirti cheminių įmaišų poveikį reologinėms portlandcemenčio tešlos savybėms, panaudojant skirtingų tipų cementus. Darbe išnagrinėta lietuvių, užsienio mokslinė literatūra, aprašytos naudotos žaliavos, parinktos skirtingos cementinės tešlos sudėtys, kurios skiriasi cemento ir plastifikuojančios įmaišos tipu. Tyrimams naudotos šios medžiagos: AB „Akmenės cementas“ gamyklos portlandcementis CEM I 42,5 (N ir R ankstyvojo stiprumo), klinties portlandcementis CEM II/A-LL 42,5 N, plastiklis Centrament N3, naujausios kartos superplastiklis MC-PowerFlow 3140 ir vanduo. Ištirtas plastiklio ir superplastiklio poveikis portlandcemenčio tešlos vandens ir cemento (V/C) santykio pokyčiams ir sklidumui naudojant Sutardo viskozimetrą. Buvo tiriamos vienodo vandens ir cemento santykio portlandcemenčio tešlos su cheminėmis įmaišomis ir be jų. Tyrimai atlikti naudojant rotacinį viskozimetrą Rheotest NH 4.1 su bendraašiais cilindrais. Nustatytas cheminių įmaišų portlandcemenčio tešloje veiksmingumas, esant skirtingo tipo cementui. Pastebėta, kad portlandcemenčio tešlos dinaminis klampis gali būti reguliuojamas cheminėmis įmaišomis viso indukcinio hidratacijos periodo metu. Sukurta metodika portlandcemenčio tešlos reologinėms savybėms nustatyti bei parinktas reologinis modelis, kuris geriausiai apibūdina gautus tyrimų duomenis. Atlikus portlandcemenčio tešlos su cheminėmis įmaišomis ir be jų tyrimų rezultatų regresinę analizę, gautos klampio, tekėjimo lygtys... [toliau žr. visą tekstą]The purpose of this thesis is to analyse the influence of chemical admixtures on the rheological properties of Portland cement paste, which differ depending on the type of cement used. In addition to the literature analysis, different cement paste compositions (differing in type of cement and plasticizers) were tested. Testing materials: Portland cement CEM I 42.5 (N and R early strength), limestone Portland cement CEM II/A-LL 42.5 N, plasticizer Centrament N3, the latest generation superplasticizer MC-PowerFlow 3140 and water. Research focused on effects of plasticizer and superplasticizer on water and cement (W/C) ratio and Portland cement paste slump-flow characteristics. Portland cement pastes with the same water-cement ratio with and without chemical admixtures were tested. Tests were carried out using a Suttard viscometer and rotation viscometer Rheotest NH 4.1 with coaxial cylinders. It was observed that viscosity of Portland cement paste can be controlled by chemical admixtures during the hydration induction period. The work provides analysis of the effectiveness of the chemical admixtures on the rheological properties of the Portland cement pastes, comparing it with a control composition of the Portland cement paste. Diagrams demonstrate changes in viscosity of the Portland cement pastes depending on the type and amount of the chemical admixtures. Obtained results were compared with the same consistence paste without admixtures. We created a new methodology of... [to full text]
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Mendlik, Matthew T. "Syntheses and investigations of 2,6-dideoxysugars contained in diverse bioactive compounds." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1120673161.
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Thesis (Ph. D.)--Ohio State University, 2005.Title from second page of PDF file. Document formatted into pages; contains xix, 347 p.; also includes graphics. Includes bibliographical references (p. 183-192). Available online via OhioLINK's ETD Center
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Flimelová, Miroslava. "Stanovení stárnutí bavlny pomocí změny polymeračního stupně celulózy." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2010. http://www.nusl.cz/ntk/nusl-216661.
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The degree of polymerization (DP) is the main factor which plays a role in cellulose aging. The adverse consequence of cellulose fibers aging is the deterioration of mechanical and optical properties. Viscometry is a technique which is frequently used for determination of degree of polymerization of cellulose fibers. The aim of the work was to determine the degree of polymerization of cotton fabrics and to investigate the dependence of DP on number of washing and dying. Next task was to investigate if there exists a corellation between DP and results from thermal and thermo-oxidative degradation studied by methods of thermal analysis. First, the traditional viscometry was employed to determine DP of cellulose fibers. It has been demonstrated that number of washing and dying decreases the DP. In the second part the differential scanning calorimetry (DSC) and thermogravimetry (TG) were used. DSC provided values of combustion heat and TG allowed the detail evaluation of degradation steps; obtained results were further used for correlation with DP. Methods of thermal analysis revealed differences between cotton wool and treated fabrics. Combustion heat did not show any correlation with DP. In contrast, results from TG suggested some promising correlations which could be used for the prediction of cotton fabrics DP using thermal analysis in the future.
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Bernardoni, Fausto. "Caratterizzazione delle proprietà reologiche dei bitumi tiepidi fluidificati ed identificazione di una procedura ottimale di invecchiamento." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amslaurea.unibo.it/2857/.
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Denison, Tracy Adam. "The effect of fluid shear stress on growth plate." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29603.
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Thesis (Ph.D)--Biomedical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Boyan, Barbara; Committee Co-Chair: Schwartz, Zvi; Committee Member: Bonewald, Lynda; Committee Member: Jo, Hanjoong; Committee Member: Sambanis, Athanassios. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Skalický, Lukáš. "Vysokotlaký viskozimetr." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230574.
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The master´s thesis describes design of falling ball high pressure viscometer for measurements of rheological properties of liquids under high pressure and in the wide temperature range. The design is based on similar apparatuses, which are described in literature. The speed of falling sinker is measured by two optical senzors. Apparatus allows measuring of viscosity, density and optical observing structure of liquid. There was developed extensive program for the evaluation of measurement in Matlab. Apparatus is placed in the laboratory of the Institute of Machine and Industrial Design FME BUT and is used for research and creative activities.
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Wang, Xi. "Drop-on-demand inkjet deposition of complex fluid on textiles." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26624.
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Thesis (Ph.D)--Polymer, Textile and Fiber Engineering, Georgia Institute of Technology, 2009.Committee Chair: Wallace W. Carr; Committee Member: Anselm Griffin; Committee Member: Carson J. Meredith; Committee Member: David G. Bucknall; Committee Member: Jeffrey F. Morris. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Spelling, Victor, Mathias Axelsson, Lovisa Ringström, af Rosenschöld Johanna Munck, and Anton Lindblad. "Mapping the intrinsic viscosityof hyaluronic acid at high concentrations of OH-." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-325348.
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Hyaluronic acid is commonly used in dermatological fillers in the form of gels. It is established how these gels' firmness is affected by the amount of cross linker and hyaluronic acid respectively. However, the effect of hydroxide ions in solution is rather unknown. This thesis examines how the alkalinity of the solvent affects the intrinsic viscosity of 3 MDa hyaluronic acid by using the method of Ubbelohde capillary viscometry. Sodium hydroxide solutions between 2 and 10 wt% were prepared to study the variation in intrinsic viscosity at concentrations relevant for cross linking (1<wt%). From these respective solutions, four solutions of different mass concentrations of hyaluronic acid were made. The flow time of respective samples were measured between two points in the capillary viscometer in a controlled temperature of 25 °C with an SI Viscoclock to ensure a high accuracy.From the resulting flow times, the intrinsic viscosity was calculated. The intrinsic viscosity varied between 0,55 and 0,70. The relation between intrinsic viscosity and hydroxide ion concentration had a correlation coefficient r < 0,001. No trend could be ensured as the confidence interval for the intrinsic viscosity at the different concentrations was too large.
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Gromeš, Vít. "Studium reologických vlastností betonů s přídavkem polymerních vláken upravených nízkoteplotním plasmatem." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-225912.
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Polypropylene fibers are used in concrete mixtures to avoid early cracks during shrinkage. Low thickness of each fiber and low density are reasons, why these fibers are effective in small dosage. Their disadvantages are smooth surface and hydrophobic character of polypropylene, thus it is necessary to improve their surface for better spread during mixing and to reach needed adhesion between fibers and cement paste. In present time are using chemical solutions applied on surface of the fibers to provide better water absorption, but the trend is reducing of using chemicals in industry and this situation demands new technology. There is possible solution, polypropylene fibers treated by low-temperature plasma. This method was developer by cooperation Masaryk University in Brno with company KrampeHarex and Brno Universiry of Technology. The goal of this thesis is to bring comparison, of influence on rheology properties of fresh concrete, between admixed the fibers with applied chemical layer and low-temperature plasma treated polypropylene fibers.
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Sadinski, Robert J. "The High Pressure Rheological Response of SAE AS 5780 HPC, MIL-PRF-23699 HTS, and DOD-PRF-85734 Lubricants." University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron1627035576924735.
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Sousa, Kenia Garrido Marques de. "Estudo Viscosimétrico de Soluções de Pré-Polímeros Uretânicos à Base de Poli(Glicol Propilênico) e Diisocianato de Isoforona." Universidade do Estado do Rio de Janeiro, 2006. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=104.
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Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de JaneiroNeste estudo, o comportamento em solução diluída de pré-polímeros uretânicos à base de poli(glicol propilênico) (PPG) e diisocianato de isoforona (IPDI) foi avaliado por medidas viscosimétricas a 30 C em dois tipos de solventes, com diferentes polaridades: isopropanol e tolueno. Os pré-polímeros foram sintetizados em massa, ou seja, na ausência de qualquer solvente, e nas formulações foram variadas as razões entre o número de equivalentes-grama de grupamentos isocianato e hidroxila [NCO/OH] e a massa molar do PPG. Os pré-polímeros foram caracterizados por espectrometria na região do infravermelho. No tratamento matemático dos dados viscosimétricos, foram empregadas cinco diferentes equações para determinar os valores de viscosidade intrínseca: Huggins; Kraemer e Schulz-Blaschke, por extrapolação gráfica; e Solomon-Ciuta; Deb-Chanterjee e; novamente, Schulz-Blaschke, para determinações por um único ponto. Os valores de viscosidade intrínseca obtidos pelos dois métodos (extrapolação gráfica e por um único ponto) foram comparados a fim de se verificar a validade da determinação por um único ponto para os sistemas analisados, bem como determinar qual equação seria a mais adequada para esse tipo de cálculo. Foram calculadas as constantes viscosimétricas de Huggins, Kraemer e Schulz-Blaschke, e foi feita uma análise da qualidade do solvente.
In this study the behavior of urethanes prepolymers based on poly(propylene glycol) (PPG) and isophorone diisocyanate (IPDI), in diluted solutions, were studied by viscosimetric measurements, at 30 C, in two types of solvents with different polarities: isopropyl alcohol and toluene. The prepolymers were synthesized in bulk, i.e, in the absence of solvent. In the formulations were varied the ratio between the equivalent-grams number of isocyanate functional groups and hydroxyl group [NCO/OH] and PPG molecular mass. The prepolymers were characterized by infrared spectrometry (FTIR). Five different equations were used to determine intrinsic viscosities values: Huggins; Kraemer and Schulz-Blaschke, by graphic extrapolation; and Solomon-Ciuta; Deb-Chanterjee and; again, Schulz-Blaschke, by a single point determination. The intrinsic viscosities values obtained by two methods (graphic extrapolations and through a single point determination) were compared in order to verify the validity of the single point determination for the systems studied, as well as the more accurate equation for this type of calculation. Viscometric constants from Huggins; Kraemer and Schulz-Blaschke equations were also determined to verify solvent quality.
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Ridell, Annika. "Characterisation of Aqueous Solutions, Liquid Crystals and Solid State of Non-ionic Polymers in Association with Amphiphiles and Drugs." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ-bibl. [distributör], 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3607.
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Gholami, Mohammad. "Shear Induced Migration of Particles in a Yield Stress Fluid." Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1502793185991791.
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Bezzaoucha, Fatiha. "Nouveaux polyamphiphiles cationiques : synthèse et étude de leur organisation en milieu aqueux et aux interfaces en relation avec leur structure." Thesis, Vandoeuvre-les-Nancy, INPL, 2008. http://www.theses.fr/2008INPL026N/document.
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Dans le but d’approfondir les connaissances fondamentales entre la structure des polymères associatifs intramoléculaires (polysavons) et leurs propriétés physico-chimiques en milieux aqueux, trois nouvelles familles de polymères amphiphiles cationiques ont été synthétisées par deux méthodes complémentaires permettant une grande variabilité de structure. Les polymères obtenus sont des poly(méth)acrylamides en peigne avec des groupes latéraux de type ammonium quaternaire portant une chaîne alkyle de taille variable. Une étude du comportement physico-chimique de ces polymères en solution, par viscosimétrie et spectroscopie de fluorescence avec deux sondes aux caractéristiques complémentaires, montre qu’ils présentent des propriétés de polysavons qui varient progressivement avec la structure des polymères amphiphiles étudiés, notamment la longueur de la chaîne alkyle latérale, la taille de l’espaceur entre les deux sites polaires amide et ammonium quaternaire et la masse molaire moyenne en nombre. En parallèle, la tensiométrie a montré que ces polyamphiphiles ont une très faible activité à l’interface eau/air confirmant la prédominance de l’effet hydrophobe, alors que les modèles moléculaires correspondants présentent d’excellentes propriétés tensio-actives. Des films de Langmuir ont ensuite été réalisés dans le cadre de la première étude de cette importance sur des polyamphiphiles cationiques. Dans ce domaine également, la grande variabilité de structure des polymères a permis des observations originales et de dégager de nouvelles relations entre la structure du polymère et les caractéristiques des isothermes de compression obtenuesIn order to improve the fundamental knowledge of the relationships between the chemical structure of intramolecular associative polymers (polysoaps) and their physical chemical properties in aqueous media, three new families of cationic amphiphilic polymers were obtained by complementary methods offering great structure variability. The corresponding polymers were comb poly(meth)acrylamides with pendant ammonium groups with alkyl side chains of variable lengths. A first investigation of their physical chemical behaviour in aqueous solutions, by viscometry and fluorescence spectrometry with two complementary fluorescent probes, showed that they displayed polysoap properties which varied progressively with their chemical features, in particular the length of the alkyl side chain, the size of the spacer between the two polar amide and ammonium groups and the polymer molecular weight. Tensiometry confirmed the prevailing of the hydrophobic effect by showing that these polymers displayed a very weak activity at the water/air interface although the corresponding molecular models showed excellent tensio-active properties. Langmuir’s films were eventually obtained in the first study of this importance on cationic amphiphilic polymers. Here again, the great structural variability enabled original observations and new structure/properties relationships were obtained for the corresponding compression isotherms
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Bronsch, Arne. "Viscosity of slags." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2017. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-229196.
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Slags plays a significant role at high temperature processes. The estimation of the slag viscosity is vital for the safe run of e.g. entrained flow gasifiers. One opportunity of determination is rotational viscometry. This technique is disadvantageous in view of elevated temperatures, applied materials and the necessary time. Additionally, the viscosity can be predicted by the help of viscosity models, where viscosity is a function of slag composition and temperature. Due to changing slag properties within the technical processes, the calculated viscosities can hugely differ from measured ones.
In this work, the viscosities of 42 slags where measured up to 100 Pa s and temperatures up to 1700 °C. Oxidizing and reducing conditions were applied. Additionally, selected slag samples were quenched at defined temperatures to qualitatively and quantitatively determine the formed minerals by X-ray diffraction (XRD). Differential temperature analysis (DTA) was applied to find the onset of crystallization for the complementation of investigations.
The Einstein-Roscoe equation was chosen to improve the classic viscosity models. Reducing atmosphere decreased viscosity and the number of formed minerals was increased. Slags show a shear-thinning behavior above ca. 10 vol.-% of solid mineral matter. Also, Newtonian behavior was observed up to 60 vol.-%. To overcome problems with the kinetic cooling behavior of the slags, a viscosity approximation method was applied afterwards. This can result in optimized viscosity predictions when several preconditions are fulfilled.
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Le, Tuan. "Investigation of physical mechanisms during deconstruction of pretreated lignocellulosic matrix and its ability to liberate a fermentable carbon substrate in a bio-process." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30133/document.
Full textAbstract:
La biomasse lignocellulosique comprend les sous-produits agricoles et industriels pouvant être utilisés comme matière première dans des bioprocédés variés destinés à produire des molécules d'intérêt énergétique ou chimique. Ces ressources lignocellulosiques, peuvent notamment être fournies par l'industrie papetière qui est particulièrement adaptée pour les bio-raffineries modernes car elle est en capacité de produire en grande quantité un substrat ayant une faible teneur en lignine et sans composés inhibiteurs. La bagasse de canne à sucre est également un substrat prometteur par sa composition chimique simple et son abondance dans les pays tropicaux. Lors de l'utilisation de ces substrats, l'hydrolyse enzymatique constitue une étape cruciale permettant la transformation des fibres de cellulose en une source de carbone fermentescible. Si les aspects biochimiques de cette étape d'hydrolyse font l'objet de nombreuses recherches et de développements, les réactions sous haute teneur en matière sèche font apparaître des limitations physiques qui sont beaucoup moins étudiées et analysées mais constituent des verrous scientifiques et technologiques qui freinent actuellement l'utilisation de cette ressource abondante et durable. Ce travail s'inscrit dans ce contexte et propose l'étude de cette étape d'hydrolyse enzymatique de la lignocellulose en s'intéressant conjointement aux aspects biochimiques et physiques de façon à aller vers une compréhension et une maîtrise des transferts (de masse, de chaleur) dans les réactions à forte concentration en substrat. La stratégie adoptée a consisté à réaliser et analyser des réactions d'hydrolyse sous différentes conditions opératoires en travaillant dans un premier temps sur des concentrations intermédiaires (suspension semi-diluée), c'est-à-dire en introduisant, mais de façon limitée, les complexités dues aux interactions entre particules/fibres de lignocellulose. Les résultats obtenus sont ensuite utilisés pour élaborer une stratégie adaptée aux fortes concentrations. Les aspects physiques analysés sont essentiellement le comportement rhéologique du milieu réactionnel ainsi que la morpho-granulométrie des objets en suspension. Différentes métrologies, tant in-situ que ex-situ, ont été mises en œuvre et apportent des résultats complémentaires. Les études ont été menées sur un substrat de référence, le papier Whatman, et deux substrats à vocation industrielle: la pâte à papier et la bagasse de canne à sucre. La stratégie d'étude porte sur les aspects suivants: (i) le suivi de l'évolution des comportements rhéologiques et des propriétés morphologiques des suspensions au cours de l'hydrolyse, (ii) l'étude des mécanismes d'hydrolyse lors de la dégradation des substrats, (iii) l'étude de l'impact de la composition et de la structure des substrats sur les cinétiques de solubilisation et d'hydrolyse, (iv) la quantification de la contribution des différentes activités enzymatiques, seules ou en mélange par une approche physique multi-échelle et (v) le contrôle et l'optimisation des conditions d'alimentation dans un procédé discontinu alimenté (fed-batch) afin d'atteindre des conditions de milieu concentré. Les chapitres 1 et 2 de ce document sont consacrés à une étude bibliographique du sujet et à la présentation des matériels et méthodes mis en œuvre. Le troisième chapitre présente les résultats obtenus et leur analyse. Il est constitué de trois sections: tout d'abord une étude des propriétés des différents enzymes ou cocktail d'enzymes utilisés, des substrats retenus et des suspensions avec, notamment, la détermination des régimes semi-dilués et concentrés. Ensuite sont présentées et analysées les hydrolyses effectuées en milieu semi-dilué. Les mécanismes d'hydrolyse (fragmentation, solubilisation, hydratation et séparation des agglomérats) sont étudiés pour diverses concentrations et divers enzymes/cocktails. Enfin les résultats en milieu concentré sont présentés dans une dernière sectionLignocellulosic biomass consists of several agriculture and industrial by-products that can be used as raw material for several bioprocesses to obtain range of products. Among lignocellulosic sources, the pulp & paper industry is appropriated for modern bio-refining thank to pulp with low lignin content and free of inhibitory compounds. Besides, sugarcane bagasse is a very promising feedstock because of its simple chemical composition and its abundancy especially in tropical countries. In the bioconversion of lignocellulose, enzymatic hydrolysis is a crucial step that allows the transformation of cellulosic and hemicellulosic fibers into fermentable carbon sources. The lack of knowledge about physical limitations and hydrolysis mechanisms, especially at high dry matter content, stands as the main barrier which forbids the scale-up of bio-refinery processes. Thus, the efficient and sustainable use of lignocellulosic resources is currently a major challenge and need to be investigated. In this context, this PhD focused on the enzymatic hydrolysis of lignocellulose by both physical and biochemical approaches. The strategy consisted in carrying out and in analyzing the hydrolysis reactions under different operating conditions with semi-dilute suspensions. Then, obtained results were used to develop a hydrolysis strategy for concentrated suspensions. Different methodologies, in- and ex-situ analyses, were implemented and provided complementary results. From physical approach, analyses consisted in rheological behavior of suspensions as well as the morpho-granulometry of particles. The study was carried out on a reference substrate, Whatman paper, and on two industrial substrates, paper pulp and sugarcane bagasse. The strategy aimed to investigate different stakes: (i) evolution of rheological behaviors and the morphological properties of suspensions, (ii) hydrolysis mechanisms during the degradation of substrates, (iii) impact of substrate composition and structure on solubilization and hydrolysis kinetics, (iv) quantification of the contribution of single enzyme and enzyme mixture activities by multi-scale physical approaches and (v) control and optimization of feeding parameters for fed-batch process in order to access to concentrated suspension. Chapters 1 and 2 of this document are devoted to a research bibliographic and presentation of materials and methods. The third chapter presents obtained results and discussion in three sections. The first one is a study of the properties of different enzymes and substrates, in particular, the determination of semi-dilute and concentrated regime. Subsequently the enzymatic hydrolysis at semi-dilute regime is presented to highlight the hydrolysis mechanisms (fragmentation, solubilization, solvation and agglomerate separation) in relationship with enzyme mixtures and dosages. Finally, results in concentrated regime are discussed in the final section