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Calculation of electrodynamic forces in 630 A circuit breaker
Staněk, Pavel ; Bušov, Bohuslav (referee) ; Valenta, Jiří (advisor)
The aim of this thesis is to simulate the action of electrodynamic forces on current carrying path and a movable contact of the circuit breaker OEZ Modeion BH 630NE. For the calculation there is used the simulation program Ansys Maxwell. The first part is devoted to theoretical analysis of electromagnetic forces on a conductor in a magnetic field. Further I discuss the constructional design of the circuit breaker itself, especially the current path and the contact mechanism. In the next part there is (with using program Autodesk Inventor) created a simplified 3D model of the current path including an arc chamber. With program Ansys Maxwell then there is performed simulation of the acting of forces in each mode. This is magnetostatic and transient analysis for symmetrical and asymmetrical flow of the fault current. In conclusion the results obtained are evaluated and processed in the tabular way.
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Electromagnetic field mapping in biological tissues
Bereznanin, Martin ; Dlouhý, Jiří (referee) ; Rozman, Jiří (advisor)
The main objective of this study is to learn about the theory of electromagnetic field and to create a model of propagation of ultra short waves in a biological tissue. Next point of this paper is to determine a specific absorption rate (SAR) using a valid sanitary standard. A particular model solution was realized in a model environment of the program Comsol Multiphysics 3.5. A human head and a cellular phone with an intern antenna were successfully created in this model environment. First of all were entered appropriate parameters which led to a successful representation of the distribution of electric field intensity. A value of specific absorption rate taken by a biological tissue was determined in the next step. This value was compared to the value listed in a valid sanitary standard to prevent its overrun. A development of a temperature in a biological tissue was determined as well, according to a six minutes long interval stated in a valid sanitary standard.
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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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Mechanical Torque Analysis of Induction Machine Based on Magnetic Circuit Saturation
Skalka, Miroslav ; Bendl,, Jiří (referee) ; Voženílek, Petr (referee) ; Ondrůšek, Čestmír (advisor)
e main goal of this thesis is mechanical torque analysis of induction machine based on magnetic circuit saturation, oversaturated areas classification and the possibility of oversaturated areas reduction of their influence on machine properties. Whole problem is solved by finite element method in ANSYS program. Work is divided into the description and creating of electromagnetic model, a method of the induction machine equivalent circuit parameters determination, the electromagnetic field calculation by finite element method, experimental measurement using LabVIEW program with measurement accessories (PCIe card National Instruments), data processing program in DIAdem, results analysis of calculations in terms of magnetic circuit saturation, the influence of magnetic circuit material based on electromagnetic field distribution and the magnetic flux density along the air gap including spectral analysis using MATLAB and the electromagnetic torque and its parasitic torque components calculation.
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Magnetostriction vibration power generator
Šumpelová, Jana ; Singule, Vladislav (referee) ; Hadaš, Zdeněk (advisor)
This thesis deals with the idea of energy harvesting from mechanical vibration. It describes the magnetostrictive principle as a possibility to obtain an electrical energy. It is about a generator made of a beam with Terfenol-D material and a coil. The model of this device is created in Matlab/Simulink and FEMM application. For various values of measured vibration, these methods are then compared. In FEMM, you can improve energy gain by modeling of various environmental conditions and with using of another materials (e.g. by adding of permanent magnets). The outcome of the this thesis expresses the ability to harvest the energy with designed magnetostrictive generator compared to the already created models of the piezoelectric and electromagnetic generator. Based on these results, it is possible to determine which generator is more suitable for particular application.
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The role of fermions and bosons in magnetic resonance imaging
ADAMEC, Filip
Abstract Currently, there are only partial theories describing the role and application of fermions and bosons in magnetic resonance imaging, but there are no interdisciplinary theories. I believe, that by combining diverse disciplines (physics, mathematics and the medical nature of MR), an interdisciplinary theory may emerge, that can also be used as a material to deepen the knowledge of future or already active radiologists in radiological physics and magnetic resonance imaging. The following objectives have been set for this Bachelor thesis: Global target: Creation of an expert description of the role of fermions and bosons in magnetic resonance imaging using interdisciplinary communication. Sub-objectives: C1: Data processing - physics of elementary particles C2: Data processing - classical form of electromagnetic field theory C3: Data processing - structure of magnetic resonance imaging C4: Data processing - quantum mechanics of protons Due to the goals of this bachelor thesis, the following hypotheses were made: H1: The classical dimension of the physical nature of MR can be created by comparison of the structure of magnetic resonance and the classical form of electromagnetic field H2: The quantum dimension of the physical nature of MR can be created by comparison of the structure of magnetic resonance and the quantum mechanics of protons H3: The role of fermions and bosons in the description of the physical nature of magnetic resonance can be described by the comparative structure of magnetic resonance and the quantum dimension of the physical substance of magnetic with the standard model of elementary particles and their interactions In the introduction to the theoretical part of the work, I dealt with elementary particles, their physics and mutual interactions. Furthermore, these particles were divided into fermions and bosons, which were described in more detail. I devoted another part of the theory to the classical form of the electromagnetic field, where I discussed mainly Maxwell's equations. The next part was devoted to quantum mechanics of particles and at the end of the theoretical part I focused on the medical part of magnetic resonance. The practical part compares the knowledge gained in the theoretical part of this work. The results were divided into two sections, according to established hypotheses. The results of this bachelor thesis point to the relatively crucial role of fermions and bosons in magnetic resonance imaging, thus confirming all three established hypotheses. The results of this bachelor thesis point out the relatively crucial role of fermions (electrons, protons) and bosons (photons, Cooper pairs) based on verified and accepted hypotheses.
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STUDY OF CHANGES OF BIOLOGICAL MATERIAL CHARACTERISTICS IN ELECTROMAGNETIC FIELDS
Vlachová Hutová, Eliška ; Král, Bohumil (referee) ; Kolářová, Jana (referee) ; Bartušek, Karel (advisor)
Presented dissertation discusses the influence of electromagnetic fields on the weight of the particles, which are considered in this work as substances with the hub. Theoretical knowledge was practically tested on plant organisms (early somatic embryos, fungal pathogens), theoretically the influence of electromagnetic field on cell structure was modeled. It was subsequently confirmed by a practical experiment assumption about the influence of electromagnetic fields on the weight of the particles. These experiments were preceded by a theoretical study of the problem and the formulation of a solution using Maxwell's equations, from which other descriptive equations and formulas were derived. The results of the experiments were presented at several professional conferences and published in professional journals and proceedings.
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Influence of magnetic and electromagnetic fields on signals transmitted by optical fibres
Schneider, Tibor ; Vrba, Kamil (referee) ; Münster, Petr (advisor)
The diploma thesis deals with the influence of magnetic and electromagnetic fields on signals transmitted by optical fibers. Subsequently, the results of individual measured values are evaluated and analyzed, which were measured using an interferometer and a polarimeter. The first part deals with the theoretical analysis of the principles of interference and polarization of light. It further explains the basic operation of the above-mentioned devices as well as the immunity of the optical fiber to EMI. The second part of the work presents selected devices and technologies that were used as a source of electromagnetic or magnetic radiation. Subsequently, individual phenomena are plotted both in the course of time and with the help of a spectrogram or Poincaré sphere. From the measured results we can conclude that the commonly available technologies, which were selected for the diploma thesis, will not cause greater negative problems to the signal on measured frequencies in optical fibre, that could degrade the transmitted signal.
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Human Brain And It’S Modeling
Zelenka, Pavel
The project deals with the development of a computer model of human brain. The model is used in the simulation program CST STUDIO SUITE 2015 to show the distribution of electromagnetic waves. The outputs of simulations should help us with a better understanding of electromagnetic field behavior inside the brain. In real life, the model will be used for the verification of methods localizing source currents in the brain.
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Elektromagnetic field mapping in tissue
Port, Martin ; Čížek, Martin (referee) ; Rozman, Jiří (advisor)
This thesis is an introduction to the modeling of electromagnetic fields in the tissue and is focused on the knowledge of electromagnetic field theory. Maxwell's equations and their solutions are described the spread of plane waves in the environment. It also discusses the exposure limit values of specific absorbed power and hygienic limits based on the standards in force in the Czech Republic on health protection against nonionizing radiation in accordance with Government Regulation No. 106/2010 Coll. It also deals with the software interface in COMSOL Multiphysics 4.2 for solving physical modeling and simulation. There is mention of the RF module, which is used for modeling. Work mentions in detail about the menu of the program and the most important part - the Model Builder.
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