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High Pressure Viscometer
Skalický, Lukáš ; Hartl, Martin (referee) ; Křupka, Ivan (advisor)
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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Study of the interphase region of wood bonds
Chlup, David ; Dufka, Amos (referee) ; Vaněrek, Jan (advisor)
This bachelor thesis deals with summarizing knowledge on issues related to the penetration depth of the adhesive into the wood structure. In the thesis they are described all adhesion theories. We focus on the effect of viscosity and durability bond line according to varying amounts of filler adhesive. Furthermore, it is described some microscopic techniques, which measure the penetration of the adhesive into the cell structure.
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Sludge Pumping on WWTP
Fadrný, Tomáš ; Medek, Jaroslav (referee) ; Boráň, Jaroslav (advisor)
This diploma thesis deals with the best solution design for a sludge fitting, especially focusing on the right choice of pumps for the waste water treatment plant in Prostějov. The pumps were selected for a circulation pipeline, which heats up the sludge. Several measurements were carried out in order to determine the statistical evaluation of the properties of the pumped medium. The figures gained were used to calculate pressure losses.The diploma thesis is divided into two parts. The first part provides a theoretical analysis of the problem and the second part presents the results and subsequently the reasoning for the new selection of pumps in order to change the WWTP technology from the mesophilic to the thermophilic sludge digestion. The test records describing the testing of the individual samples of the pumped sludge are attached.
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The influence of a pre-print thick layer paste viscosity on forming of layer
Ondráček, Michal ; Švecová, Olga (referee) ; Klíma, Martin (advisor)
This bachelor thesis deals with the theory of thick film technology and applying these layers. The work also includes basics of liquid rheology, methods of measurement viscosity and ways of mixing liquids. The main aim is to determine the influence of viscosity of thick film pastes for printing quality of the test structure using screen printing, in particular its flatness and sharpness. The aim is also measure the dependence of viscosity thick film pastes on mixing time.
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Computational modeling of radial hydrodynamic bearings for water machines
Pokorný, Jan ; Šimek,, Jiří (referee) ; Návrat, Tomáš (advisor)
The aim of this thesis is to calculate the stiffness and damping coefficients for radial hydrodynamic bearings. Cylindrical and lemon hydrodynamic bearings are considered. The solution to this problem mainly depends on the hydrodynamic pressure in the bearing. The numerical solution of the Reynolds equation is used to calculate the pressure. The effect of variable viscosity and density of the lubricant due to temperature changes is considered. The static equilibrium position of the journal centre is also solved. The stiffness and damping coefficients are determined using small amplitude journal motions about the equilibrium position. Three methods for determining these coefficients are presented. The outcome of this thesis is an algorithm for the calculation of stiffness and damping coefficients for cylindrical and lemon bearings. Results for lemon bearings are presented and comparison with the commercial software DynRot BR is made. The benefit of this thesis is the creation of an algorithm for the calculation of journal centre equilibrium position, a new way of incorporating the temperature changes in the viscosity and the density of the lubricant, and the modification of a method for calculating stiffness and damping coefficients based on experimental analogy.
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Properties of aprotic electrolytes for lithium-ion accumulators
Staněk, Vladimír ; Máca, Josef (referee) ; Frk, Martin (advisor)
The present work deals with the properties of suitable electrolytes for lithium-ion batteries. The first part described in the current issue of electrolytes for lithium-ion batteries, types of solvents and their properties and methods of measurement properties. The second part is devoted to the measurement of the properties of solvents and electrolytes such as relative permittivity, density and viscosity. Measurement of relative permittivity was focused on the measurement of the solvent mixture with varying the percentage of the solvent. Viscosity and density were measured on a solvent with a lithium salt added (final electrolyte).
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Hydrodynamic dampers on the principle of magnetic fluid
Přikryl, Matěj ; Himr, Daniel (referee) ; Pochylý, František (advisor)
This bachelor's thesis deals with damping vibrations emerging due to the movement of a vehicle. The first section provides an overview of contemporary types of dampers with thorough explanation of the principle of hydrodynamic damper. This section also contains simulation of vibrating vehicle equipped with passive damper. Literature research of magnetic fluids and description of magnetoviscous phenomenon is presented in the second part, which freely continues to the topic of magnetorheological (MR) dampers. The final chapter firstly describes current hydrodynamic dampers based on squeeze film (SF) mode of magnetorheological fluid and at the conclusion the author's concept of SF MR damper is submitted.
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Study of emulsion stability by means of physical-chemical and optical methods
Kuchyňová, Jitka ; Veselá, Mária (referee) ; Zmeškal, Oldřich (advisor)
The diploma thesis deals with the stability determination of model O/W (30/70) emulsions at 25°C. In fact, the time and emulsifier concentration (Tego Care PS) dependences of physical properties (aging) were monitored. In the second part of the work, the influence of conservant on emulsion stabilities were studied. In order to study physical properties of emusions rheometry, differential scanning calorimetry (DSC) and optical microscopy were employed. The rheological measurement provided information on viscosity and viscoelastic modulus. DSC experiments used the repeated freezing/thawing cycles which allowed monitoring of changes in crystallization temperature of water present in emulsions and melting enthalpy of ice formed during the cooling. The optical microscopy was used to examine the change in oil droplet size in the course of emulsion destabilization and phase separation. In this case the image analysis was carried out using program HarFA. The results showed that due to the emulsion creaming, the oil droplets diffuse and aggregate which causes phase separation. Those processes were quickest for the emulsion with lowest emulsifier concentration 0.1 % (destabilization during 51 days) The emulsions with emulsifier concentration about 1.5 and 1.3 % were stable at least for 4 months. The presence of the coemulsifiers increased the elastic modulus and descreased the phase difference due to the network formation. It was shown that for the stability determination is necessary to use conservant due to risk of microbial contamination. DSC experiments allowed to distingush samples prepared under different conditions. Lower rotational speed during emulsion preparation caused the appearance of two melting and crystalization peaks while for higher speed only one peak was observed.
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Accuracy of the determination of liquid viscosity
Zikmund, Ondřej ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This master thesis is focused on the rheological properties of liquids, especially on the viscosity and the standard uncertainty. It explains methods of the viscosity measurement and the calibration selected viscometers, the principle of the determination of standard uncertainty by indirect measurement of the viscosity and the density. The main object of this thesis was to create a specialized centre for viscosity measurement and to create a document which could be used by teaching of diagnostics.
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