This diploma thesis is devoted to problems of crankshaft plain bearings at five-cylinder in-line engine. Document body describes behaviour of plain bearings under various working conditions. To needs of the hydrodynamic bearings simulations is created the cranktrain virtual model. Next part of hereof document deals with problems of bearing shell design. Is created survey of the bearing materials and shortly described technological processing of shell bearing. To understand complicated problems hydrodynamic lubrication is derived Reynolds differential equation and foreshadowed succession calculation dynamically loaded bearings. In final parts of this thesis are presented most interesting results obtained from computational analysis.

This master’s thesis focuses on hydrodynamic plain bearing drivetrain in-line sixcylinder diesel tractor engine. In the first part is used as reported in contemporary bearing materials and design solutions bearing basins. Furthermore, given the general Reynolds equation of hydrodynamic lubrication. The main part of the thesis is devoted to creating a virtual model of the crank mechanism in MBS system ADAMS/Engine. Rigid crankshaft in this model is replaced by the flexible crankshaft, which is prepared in the FEM software ANSYS and then exported. The final section presents the results of simulations and their evaluation.

Diploma thesis deals with problems of design a sludge pump with a vortex impeller. Clearly summarizes the basic information on hydrodynamic pumps with a significant focus on sludge pumps. It contains a design of a vortex impeller, which is supported by CFD (Computational Fluid Dynamic) calculation in software Fluent. The aim of the work is to design vortex impeller, which could replace the existing channel impeller while maintaining the operating parameters of the pump.

The diploma thesis is focused on a quantification of hydrodynamic load of overflowed bridge deck. Solution was pursued by using two–dimensional numerical simulation of open channel flow in vertical plane created in ANSYS 15.0 software (modules: Workbench, Design Modeler, Meshing, Fluent). Values of drag force, lift force, moment, drag coefficient, lift coefficient and moment coefficient is result of computation. Various types of bridge decks were tested in relation to the degree of inundation (inundation ratio) and flow velocity.The thesis provides comparison of numerical simulation with physical experimental testing and result published in accessible resources.

Title: The study of the association behaviour of the amphiphilic copolymers in solutions containing low molar compounds by means of computer simulations. Author: Mgr. Karel Šindelka Department: Faculty of Science, Charles University Supervisor: Doc. Ing. Zuzana Limpouchová, Csc. Abstract This doctoral thesis focuses on the study of electrostatic self- and co-assembly in complex polymer solutions containing polyelectrolyte (PE) block copolymers together with surfactants, neutral homopolymers, or oppositely charged PEs using the dissipative particle dynamics (DPD). It was shown that the electro- static self-assembly depends not only on the cooperative interactions of oppo- sitely charged PE chains, but also on the amphiphilicity of PE species or on the polymer block compatibility, among other properties. PEs with incompatible blocks create well-defined core-shell structures, while large ill-defined crew-cut aggregates form from PEs with compatible blocks In non-stoichiometric mixtures of PEs with incompatible blocks, co-assembled nanoparticles are smaller than in stoichiometric mixtures and are charged. The destabilization of larger aggregates depends on how the PE charge surplus is introduced: the effect is strongest when the density of the surplus PE charge on the PE chains is increased and weakest when the...

The subjekt of this diploma thesis is a quantification of hydrodynamic load of the overflow bridge deck using numerical simulations. The simulation was performe for eight different discharges, which correspond to different degrees of inundation of the bridge deck using different turbulent models in Flow-3D software. The result of the calculation are the values of the hydrodynamic load– the horizontal force, the vertical force and the moment acting on the bridge deck. Furthermore, drag coefficient, lift coefficient and moment coefficient were quantified. Finally, the results of turbulent models were compared with each other and with result of physical experimental testing.

The subject of this thesis is the evaluation of hydrodinamic load on a physical model of a bridge deck, especially to find the relation between the median and extreme quantiles of each hydrodanamic load part and to evaluate the influence, which has the shape of the bridge deck on the size of this load. Relations, that was found may be used to determine characteristic values of loads, caused by water flow, for example, when designing the bridge bearings.

The diploma thesis deals with experimental determination of hydrodynamic load on the overflowed bridge deck model. In the first part of the thesis the author describes the analysis of the problem together with the basic physical laws and principles that are used or assumed in the measurement itself. In the second part the author describes the measurements in the laboratory of the Faculty of Civil Engineering and its gradual processing. At the end of the work are described the results of measurement, their comparison with numerical modeling, other authors and their possible use in practice.

Capillary zone electrophoresis is frequently used in various analyses. In this diploma thesis a hydrodynamic sample introduction method controlled by pressure pulse has been proposed for short-capillary electrophoresis. The base electrolyte flushes sample from the loop of a six-way sampling valve and is carried to the injection end of the capillary. At the time when the sample zone reached the capillary, a short pressure impulse is generated in the electrolyte stream, which provides injection of the sample into the capillary. Then the electrolyte flow is stopped and the separation voltage is turned on. The amount of sample introduced to the capillary is controlled by the duration of the pressure pulse. This new sample introduction method was tested in the determination of ammonia, histidine, creatinine, uric acid and hippuric acid in human urine and for rapid screening of the contents of the inorganic ions in cerebrospinal fluid and blood plasma. The determination was performed in a capillary with an overall length of 10,5 cm and two base electrolytes was tested - 50 mM MES + 5 mM NaOH (pH 5,10) and 1 M acetic acid + 1,5 mM crown ether 18-crown-6 (pH 2,40). Using dual detection techniques contactless conductivity and UV spectrometric detection, anorganic and organic substances in the sample could...

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.