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Measurement of the Magnetic Field
Šimberský, Michal ; Uher, Miroslav (referee) ; Fialka, Jiří (advisor)
This bachelor thesis deals with the measurement of the magnetic field and sensors, which can scan the magnetic field. In this work is explained the principle of Hall probes and three types of magnetic field sensors based on magnetoresistive principles namely AMR, GMR and TMR sensors. The thesis also deals with the generation of a homogeneous magnetic field with Helmholtz coils and design of such a coil.
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Image processing of MRI
Němcová, Simona ; Jiřík, Radovan (referee) ; Krátká, Lucie (advisor)
This thesis deals with the cartilage imaging using magnetic resonance. At first, there is mentioned physical principle of the magnetic resonance phenomenon and the most commonly used excitation sequences, followed by the description of the 9.4 T MR imaging system Bruker BioSpec 94/30 USR, which was used for measurement in the practical part. The next part is dedicated to the composition of cartilages and describes the temporomandibular joint, due to its suitability as an object for cartilage imaging. The series of MR scans of temporomandibular joint were taken with different acquisition parameters and evaluated by program designed through the MATLAB software. The program can be used for viewing scanned images, evaluating their contrast and determining the T1 relaxation time of the tissues by creating T1 maps.
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The effect of magnetic field and other selected stressors on physiology of bacterial cells
Mrázová, Kateřina ; Mravec, Filip (referee) ; Obruča, Stanislav (advisor)
This thesis deals with the effect of magnetic field and organic substances, namely benzene and p-nitrophenol, on cell of PHA producing bacteria Cupriavidus necator H16 and mutant strain Cupriavidus necator PHB4, which does not produce polyhydroxyalkanoates. Static magnetic field was generated by both permanent magnet and electromagnet. The effect of magnetic field on the growth of bacterial cells was studied using growth curves. It was found that cultivation in magnetic field and mineral medium mostly inhibits bacterial growth. Also the amount of polyhydroxyalkanoates was observed using FT-IR, flow cytometry and microscopy with fluorescent dye. Growth curves and flow cytometry were also used to study the influence of organic substances on bacterial cells. It was found that while benzene does not affect either C. necator H16 or C. necator PHB4, p-nitrophenol acts as the inhibitor of bacterial growth for both cultures. Finally the impact of p-nitrophenol on the accumulation of PHA was studied using gas chromatography.
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Mapping and homogenity correction of basic magnetic field in tomograph
Žůrek, Dalibor ; Kubásek, Radek (referee) ; Hadinec, Michal (advisor)
This work focuses on a search of available literature in the field of mapping the magnetic field and the degradation of the field gradients. Initially on introduction to basic concepts in the field of magnetic resonance imaging, which are important for understanding the problems and become familiar with the principles of measurement of magnetic fields on the selected surface. Furthermore, there are described two basic measurement techniques, magnetic resonance imaging. The work is analyzed the degradation patterns of magnetic field gradients using the Taylor series and spherical functions. The second part describes how to obtain readings in the tomograph, which together with the previous decomposition of the field then used to describe a numerical calculation of magnetic induction on the surface of a sphere. Values measured and calculated values are compared at the end.
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Calculation and optimization of synchronous servomotor reluctance torque.
Kroupa, Martin ; Hájek, Vítězslav (referee) ; Ondrůšek, Čestmír (advisor)
This work is mainly focused on construction and design simulation of synchronous servomotor. This motor is built by 30 permanent magnets which are attached to rotor and solved in Ansoft Maxwell 14 software. The main purpose was to calculate reluctance torque, which is significant during the motor operational mode and its optimization. Ansoft Maxwell 14 can analyze in 2D mode as well as in 3D mode, for analysis it uses method of finite elements. Subjects can be analyzed in static conditions, or in any way of transient movement. Optimization in 2D, where we will change the shape in the area of air gap, will only be used as revision that the reluctance torque is bounded with this factor. The main simulations were supposed to be done in 3D model, where the role of rotation should have been taken in account to the final result. These simulations were replaced by alternative calculation. On behalf of achieved results, the optional rotation is stated in the end of my work.
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Magnetic field analysis with finite element method and magnetic sensor
Volf, Tomáš ; Kurfűrst, Jiří (referee) ; Skalka, Miroslav (advisor)
The magnetic field analysis by MKP and magnetic probe project deals with magnetic field analysis of asynchronous machine cross section. This analysis is written in detail along with the necessary theory of asynchronous machine and the ANSYS program. The magnetic field of selected machine is measured by magnetic probe and results are compared with calculation. The next part of thesis is draft of device for the magnetic field analysis.
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Stray losses calculation of induction machine
Jirásek, Tomáš ; Hájek, Vítězslav (referee) ; Ondrůšek, Čestmír (advisor)
The main goal of this thesis is a determination of an idle stray losses in induction machine and creation calculation program in MATLAB. The stray losses are caused especially by the eddy currents on the surface of stator and rotor, further by a pulsation of these currents owing to the periodical change of air-gap permeance, magnetic induction in stator and rotor teeth and a differential leakage. Value of stray losses are different of engine construction especially by it are scoring insulated, uninsulated, straight or slant.
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Application for magnetic field mapping using F.W.BELL 9950
Kohnheiser, Jan ; Kubásek, Radek (referee) ; Hadinec, Michal (advisor)
The aim of this project is to acquaint the reader with the possibilities of controlling gaussmeter FW Bell 9950 by computer. The thesis analyzes the problems of measurement of magnetic flux density and the measuring instrument itself and its ability to communicate with the PC will be introduced. Next part of the thesis deals with the description and control of the application designed for communication and mapping magnetic field with F.W. Bell 9950.
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