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Universal CNC machine extensions for additional functions
Pavelka, Ondřej ; Mačák, Martin (referee) ; Jaššo, Kamil (advisor)
Technology of 3D printers, which are regarded as a representative of a CNC machines, are the central point of this diploma thesis. Apart from the history and theory of 3D printers with the emphasis at their functioning principles, firmware, different methods of 3D printing and their respective kinematics, there are chapters concerned with typical CNC machines as well. There is insight into programming of CNC machines and different types of CNC machines regarding their utilization in many industries. The practical part of this diploma thesis is covering conversion of the real VUT FDM 3D printer to a universal modular machine. This conversion was preceded by identification and elimination of a faults, which this 3D printer had and therefore haven’t been capable of becoming functional modular machine. With the aim of increasing the actual value and its utilization there were two switching modules created. One for 3D printing and second for extruding paste like materials.
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Load tests of non-IT parts of data centers
Víteček, Aleš ; Mačák, Martin (referee) ; Vyroubal, Petr (advisor)
The thesis "Load testing of non-IT parts data centers" deals with the theoretical analysis of data centers with a focus on non-IT part and theoretical preparation for measuring stress tests focused mainly on cooling. The theory is followed by a practical part of the PEC measurement by CATEGORY a.s .. This sample measurement carried out at the company premises clearly outlines the importance of performing similar tests. The measurement is thoroughly evaluated and suggestions are made to improve the operation. The next part of the practical part contains simulation of sample measurement. This simulation serves as a convenient addition and comparison. Also this simulation, the importance of similar stress tests can be justified.
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Analysis of the fluid mixing in the circulation reactor
Mačák, Martin ; Vyroubal, Petr (referee) ; Maxa, Jiří (advisor)
This work deals with an analysis of the fluid mixing in pilot plant loop reactor. Multiphase flow was simulated with calculation of velocity of flow and volume fraction of individual immiscible phases in hydrogenation reactor for aniline production. Parameters of flow were reviewed in individual parts of the device. Separate attention was paid to heat transfer through wall of the device with usage of external cooling. Designed model is applicable for optimalization and design of bubble loop reactors.
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Electro-Magneto-Hydrodynamic Model for Electron Microscopy
Mačák, Martin ; Horák, Vladimír (referee) ; Uruba, Václav (referee) ; Vyroubal, Petr (advisor)
This dissertation thesis deals with the description and development of an electromagneto-hydrodynamic model intended for electron microscopy. The basis of the work lies in the description of characteristic phenomena taking place in electron microscopes with a focus on environmental electron microscopy. The work dealt with a description of the electromagnetic field, supersonic flow of rarefied gas and a motion of relativistic charged particles in a gaseous environment. An electromagnetic model based on the definition of electric and magnetic vector potential was presented and was used for a simulation of an electromagnetic coil. The supersonic flow of a rarefied gas was defined by Navier-Stokes equations. In order to extend their application to low pressures, the boundary conditions for velocity and temperature were modified. Viscosity and thermal conductivity were subsequently introduced as functions of gas pressure. These adjustments were able to describe the effects of lower collision frequency of gas particles. The presented model was used for the analysis of a flow through a separate aperture and a differentially pumped chamber. Furthermore, the model and necessary adjustments for the description of relativistically moving particles were presented. The model was used for the simulation of electron optics. Separate attention was paid to the interaction of charged particles with a gaseous environment. These interactions had a stochastic character and the presented model described both elastic and inelastic collisions. The presented multiphysics model enables the simultaneous simulation of different physical areas and the interactions between them, which leads to a possibility of a more detailed description of processes and to the improvement of environmental electron microscope design.
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Numerical Modelling of Hypersonic Flow of Spacecrafts
Mačák, Martin ; Vyroubal, Petr
Numerical simulations of rarefied gas flows are an important area in the design of aerospace vehicles. They can provide a suitable alternative to experiments, which can be often too complicated due to extreme conditions. Navier-Stokes equations, which describe continuum fluid flow, generally lose their applicability in low pressures. As a result, it is necessary to adjust these equations or use alternative models. This article studies the possibility of using a continuum numerical model for a simulation of a hypersonic flow of a reentry module. Based on the Knudsen number, it was shown that it is still possible to use Navier-Stokes equations either without any adjustments or with the addition of a slip flow boundary condition.
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Numerical modelling of Li-S batteries
Mezera, Petr ; Jaššo, Kamil (referee) ; Mačák, Martin (advisor)
This work deals with modeling and simulation of Li-S batteries in Matlab. The work describes the properties of these batteries, their construction and the problems associated with their development. Furthermore, experimental techniques and their importance for numerical modeling of batteries are discussed. Different types of battery modeling are described in the work, then numerical models for simulations are analyzed in more detail. The procedure for making the Li-S battery is described and the measurements made on it are described. The measured data has been adapted for use in several different ECMs. Finally, models of a replacement circuit for the Li-S battery were built. One model accounted for the polynomial equations and the other the resulting circuit. The latter used linear interpolation and was more accurate.
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Precise drug targeting using electromagnetic fields
Matějka, Alexandr ; Vyroubal, Petr (referee) ; Mačák, Martin (advisor)
The present bachelor thesis deals with the study of electromagnetic fields used for precise drug targeting from the point of view of numerical simulations. This area is very interesting from different points of view. The use of numerical simulations is currently a very attractive, but not widely used solution. In this bachelor thesis, a numerical model is developed to model the phenomena under investigation. Furthermore, the effect of the proximity of the magnetic field source on the targeting efficiency of drug carriers was analyzed in this thesis. The use of simulations of the presented issue can help to streamline and accelerate the application of the stated methods in practical applications.
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Calibration and evaluation of data from strain gauges
Dubina, Jozef ; Mačák, Martin (referee) ; Vyroubal, Petr (advisor)
This thesis describes calibration and evaluation of data measured from tensometric sensors. The labour describes tensometers in general, their functions, aplications and principle of operation. Loading data from tensometric sensors is next part of this labour, where are information how to convert analog to digital signal output, which is ready for processing and shows real values. After signal is converted to digital signal, is needed to calibrate tensometers to receive high precission values of weight according to reference load. Thesis describes choices of electronic and mechanical components for building digital scale. Software developing for this electronic equipment is described in next part of thesis.
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Universal CNC machine extensions for additional functions
Pavelka, Ondřej ; Mačák, Martin (referee) ; Jaššo, Kamil (advisor)
Technology of 3D printers, which are regarded as a representative of a CNC machines, are the central point of this diploma thesis. Apart from the history and theory of 3D printers with the emphasis at their functioning principles, firmware, different methods of 3D printing and their respective kinematics, there are chapters concerned with typical CNC machines as well. There is insight into programming of CNC machines and different types of CNC machines regarding their utilization in many industries. The practical part of this diploma thesis is covering conversion of the real VUT FDM 3D printer to a universal modular machine. This conversion was preceded by identification and elimination of a faults, which this 3D printer had and therefore haven’t been capable of becoming functional modular machine. With the aim of increasing the actual value and its utilization there were two switching modules created. One for 3D printing and second for extruding paste like materials.
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Design and construction of a magnetorquer
Sedlařík, Marek ; Mačák, Martin (referee) ; Vyroubal, Petr (advisor)
This diploma thesis deals with the issue of satellite control using a magnetic field. Describes the physical principle of the magnetorquer and its interaction with the Earth's magnetic field. It contains a summary of advantages and disadvantages of individual solutions and their comparison with alternative control systems. Includes a search of currently available devices. It introduces the standardized CubeSat nanosatellites, their subsystems and ECSS standards, which define the parameters of equipment for space applications. It deals with the issue of the geomagnetic field, its fluctuations and describes selected orbits of the planet Earth. The main part of the work contains a description and implementation of the test system, which consists in the design of the printed circuit board, the program part of the test board and the user interface. This part also includes a detailed design and implementation of a two-axis magnetorquer, including simulations.
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