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Precision and dynamics of linear piezo motors
Ilichman, Ondřej ; Vaške, František (referee) ; Houška, Pavel (advisor)
The work deals with the design, control, precision and dynamics of linear piezoelectric motors from PiezoMotor Uppsala AB. The aim of this thesis is to evaluate the applicability of the loaned engine in a mass spectrometer. In introduction‘s section of this work is discussing the design principles of functionality, materials used, procedure and types of piezoelectric motors. It focuses the choice of hardware and design of mechanical assemblies, which could replace the current mechanism with electromagnetic motors. Then we designed and fabricated a test report with hired piezoelectric motor. In NI LabView development environment is created test application for control and measurement. The final section is devoted to a summary of the positive and negative features of the hired piezoelectric motor and evaluation of accuracy and dynamics.
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Numerical modeling of free ions movement
Sukup, Luboš ; Steinbauer, Miloslav (referee) ; Fiala, Pavel (advisor)
This work deals of movement free ions in environment, which is affected by acting of electric field, magnetic field and their interacting. In first part is work focused on numerical methods, which solve exemplars situations. Here is important to properly choose adequate numerical method. Second part of this work interprets influence of these fields on the ions and influence of environment on final motion. The last experimental part is focused on model of cylindrical capacitor as a sensor, which models nonuniform electric field.
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Dielectric properties of liquid insulators
Jahn, Michal ; Starý, Jiří (referee) ; Špinka, Jiří (advisor)
This master‘s thesis deals with measurement of liquid dielectric materials (insulators). Above all, it is the different kinds of clean and drinking water, but also transformer oils. There was done theoretical information retrieval about the given topic in this project and on the basis of theory there were realized the relevant measurements of selected properties of liquid dielectric, such as permittivity, capacitance, loss number, conductivity, but also temperature dependence of these parameters. The measurements were realized with the help of product manufactured at the faculty FEKT VUT and with the help of measuring system AGILENT 16452A. The measured results were evaluated, graphically processed and compared.
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Measurement of anechoic chambers
Švec, Marek ; Nováček, Zdeněk (referee) ; Dřínovský, Jiří (advisor)
This Master’s project deals with general aspects and possible solution of effective shielded cover and cell/chamber shielding measurement for needs of electromagnetic compatibility EMC on the basis of available norms and standards. Electromagnetic shielding is one of the most anticlutter means of EMC. Its main task is reduction of disturbing emission at the side of sources of disturbing signals as well as electromagnetic resistance increase at the side of disturbing signal receivers. Shielding is considered to be an important structural means to reduce electromagnetic field referring to a defined space part. Technical means for achieving the given goals are called shielded covers or shielded cells/chambers. Shielding is one of highly effective methods related to electromagnetic protection, for instance against power/output disturbance. To express the shielding quality so called shielding effectiveness SE is used. It represents logarithmic rate of shielding coefficient that is defined by the intensity ratios of electric and magnetic fields in a certain point of the shielded space to electric or magnetic field intensity incident/impinging on the shielded screen or wall.
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On behaviour of PVB solutions in electrospinning
Švrčinová, Petra ; Lubasová, D. ; Filip, Petr ; Martinová, L.
Electrospinning produces nanofibre sheets from polymer solutions under high electric field. Rheological properties of these solutions play a substantial role in a nanofibre formation simultaneously with properties of polymers and solvents applied. This contribution aims at a determination of dependence of shear viscosity of polyvinylbuthyral (PVB) on the intensity of electric field to which PVB solutions are exposed. PVB was dissolved consecutively in a series of solvents as 10% wt. solution. It was found that the viscosity ratio (viscosity of a solution in presence of electric field/viscosity of a solution in absence of electric field) depends on the polarity of solvent. This pre-determines the possibility of application of the individual solvents for the process of electrospinning.
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Pohyb nabitých částic v perturbovaných magnetických polích tokamaku
Papřok, R. ; Krlín, Ladislav ; Cahyna, Pavel ; Riccardo, V.
In this paper we present two Hamiltonian approaches–full and drift–for description of charged particles (e.g. electrons, D+) in magnetic field of a tokamak. We use a basic magnetic toroidal field configuration with shear plus overlapping island chains creating magnetic ergodic layer. We would like to use this apparatus for solving two physical problems. Firstly for an estimate of generation of electric field in edge plasma caused by addition of “ergodic coils”, which could serve as a mechanism for mitigation of ELMs and is will be studied on the COMPASS tokamak. Secondly we want to use the apparatus for tracing the influence on runaway electrons (energy 10 MeV) in the presence of magnetic field generated by Error Field Correction Coils (EFCCs) as are installed on JET Tokamak.
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Studie integrálního uspořádání magnetohydrodynamického čerpadla pro transport roztavených kovů či solí
Kotlan, V. ; Doležel, Ivo ; Ulrych, B.
The paper deals with one of the fundamental possibilities of improving magnetohydrodynamic (MHD) pumps based on the integration of effects of elementary MHD minipumps distributed along the pipe through which they transport the considered liquid. The crucial point of the work consists in computer modeling of this integral arrangement (system of minipumps) and presentation of the results that demonstrate their advantages–reduction of electric currents flowing through the minipumps and consequent reduction of the total ohmic losses in the system.
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Numerické modelování MHD jevu při čerpání tekutých kovů
Büllow, J. ; Doležel, Ivo ; Karban, P. ; Ulrych, B.
The paper deals with the numerical modeling of pumping molten metals based on the principle of the magnetohydrodynamic effect, i.e. force effect of an external stationary current field and magnetic field on an electrically conductive liquid. Described is the physical essence of the effect that represents the starting point for the formulation of its mathematical model. The theoretical analysis is illustrated on two examples. The first pump works with practically uniform electric field in a hydrodynamically less favorable channel of rectangular cross-section while the second one with nonuniform electric field in hydrodynamically more advantageous circular channel. The conclusion is devoted to the discussion about the possibilities of optimization of the device.
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Analýza relaxačních jevů v tokamaku CASTOR vyvolaných nabíjením okrajového plazmatu hluboce vnořenou elektrodou
Brotánková, Jana ; Stöckel, Jan ; Hron, Martin ; Štěpán, Michal ; Peterka, Matěj ; Horáček, Jan ; Ďuran, Ivan ; Spolaore, M. ; Peleman, P.
Transport of plasma to the walls is one of the crucial topics in magnetic confinement fusion research. In tokamak CASTOR, during special regimes with strong biasing of plasma, we can observe relaxation events, corresponding to increasing and collapsing of a transport barrier. High spatially and temporally resoluted arrays of probes enable us to describe these phenomena in details.
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Integral Solution of Electrostatic Fields in 3D Arrangements
Hamar, R. ; Doležel, Ivo ; Ulrych, B.
The paper deals with computation of 3D electrostatic fields (distribution of charges, electric potential and other derived quantities) by means of integral equations and their numerical solution. Selected are neither configurations that can be simplified to 2D problems and solved analytically, nor arrangements that might be processed by the FD or FE techniques. Analysed are fundamental mathematical aspects of the method, which is illustrated on a 3D field between two cubes in general position.
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