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Support of Mapping by Image Processing
Jaroš, Ján ; Herman, David (referee) ; Váňa, Jan (advisor)
This bachelor's thesis deals with methods of detection of selected objects in video and with importing these objects into OpenStreetMap central database based on their geographic location. It focuses mainly on recognition of road signs. First section briefly describes some of the most widely used methods and OpenStreetMap project itself. In the following chapters is given a more detailed overview of used methods of proposed system, its implementation and testing. The conclusion contains evaluation of whole work and the possible improvements are listed here.
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Development of 3D metal printing process parameters for producing of the lattice structure
Jaroš, Jan ; Koutný, Daniel (referee) ; Vrána, Radek (advisor)
Selective laser melting (SLM) in additive technology, which allows production of lattice structures. Lattice structures are very difficult to produce using conventional methods. The main use of lattice structures is in aerospace industry and medicine for bone implants production. In this work influence of processing parameters (laser power, scanning speed) on properties (diameter, surface roughness, porosity) of struts is investigated. The processing parameters selection was based on single tracks test. In the first test, ImageJ was used to determine porosity of struts. In the second test porosity was analyzed with more accurate µCT technology. Both tests used 3D scanning technology to determine dimension accuracy and surface roughness of samples. The measurement results led to the detection of processing parameter „window“ where samles had the best combination of surface roughness and porosity. The best results were achieved with 225-275 W laser power and scanning speed of 1400-2000 mm·s-1.
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The developement of SLM laser strategy for lattice structure fabrication
Jaroš, Jan ; Dočekalová, Kateřina (referee) ; Vrána, Radek (advisor)
Additive technology (AT) is increasingly used to design unique parts, mainly due to the ability to produce complex structures such as lattice structures. However, this also includes the need to modify the process parameters or the production strategy of the AT, which is usually set to produce volume geometry. Using samples corresponding to the geometries of the lattice structures, the exact input values were measured, which were used to design the SLM (Selective laser melting) production process using a contour strategy. Thanks to this, vertical and angled (35.26°) struts with low porosity (up to 0.2 %), low surface roughness and high dimensional accuracy were produced. Porosity was measured on µCT, surface roughness and dimensional accuracy were measured on STL data. The results show that if the parameters of the SLM process are set correctly, it is possible to produce struts with low porosity and surface roughness using different combinations of laser power and scanning speed. The above findings were used in the creation of script that allow the selection of suitable process parameters to produce lattice structures.
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Experimental investigation of mechanical properties of structures made by metal 3D print
Porubský, Radek ; Jaroš, Jan (referee) ; Vaverka, Ondřej (advisor)
This bachelor thesis deals with shear testing of lattice structures produced by the Selective laser melting technology. The testing method was based on the ASTM D7078 standard, which deals with the testing of composites. BCC and FCC lattice structures with different strut diameters were selected for the experiment. The work describes the course and results of shear test. These real results are compared with results of finite element analysis. The results compare the properties of structures depending on the diameter of the strut, the type of structure or the direction of loading. The influence of Selective laser melting production technology on the properties of structures under shear loading is also discussed. For example, the results showed that the FCC structure has better mechanical properties under shear loading than the BCC structure. For both structures, it was also confirmed that structures with a larger strut diameter have significantly better properties than those with a smaller strut diameter.
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Mediation in the Czech Republic
Jaroš, Jan ; Macková, Alena (advisor) ; Zahradníková, Radka (referee) ; Dörfl, Luboš (referee)
NÁZEV DISERTAČNÍ PRÁCE V ANGLICKÉM JAZYCE, ABSTRAKT V ANGLICKÉM JAZYCE A 3 KLÍČOVÁ SLOVA V ANGLICKÉM JAZYCE Mediation in the Czech Republic A doctoral thesis represents an evaluation of the fulfillment of the legislator's predicted objectives and expectations placed into the adopted legislation of mediation after ten years of its effectiveness in the legal system of the Czech Republic. The text is divided into two main sections. The first section deals with topics related to the Act on Mediation and the Decree on Examination and Mediator's Remuneration. The second part is concerned with the consequences and connections that are not explicitly regulated by such legislation. In the specific chapters, the expectations of the legislator and subsequent opinions arising from ten years of expert discussion are presented. The author's own conclusions formed using appropriate methodological procedures, especially analytical, normative and empirical approach follows. If possible, available statistical data and partly also foreign examples were used in the thesis. In the first part, the addressed topics are (i) the duplex legal regulation of mediation, (ii) the consequences of such duplexity, i.e. advantages and disadvantages for the mediator and participants, (iii) the performance of mediation according to the Trade...
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Impact loading of lattice structures produced by Selective Laser Melting technology from magnesium alloy WE43
Foltán, Tomáš ; Červinek, Ondřej (referee) ; Jaroš, Jan (advisor)
Strut-based lattice structures manufactured with magnesium alloy WE43, due to their high strength-to-weight ratio, seem like an ideal solution for biomedical and aerospace industries. Previous research has focused mainly on the behaviour of these structures under quasi-static stress conditions. Dynamic stressing of these structures has not been deeply researched. Therefore, this work deals with impact testing of strut-based lattice structures manufactured by SLM. Low-velocity impact tests were performed on a set of cell topologies with different strut diameters. Absorbed energy, stress-strain curve, and deformation mechanism of each sample were studied. Clear effect of cell topology on the amount of absorbed energy was observed, where structures of similar relative densities displayed considerably different values. Highest specific absorbed energy was achieved with the FCCZ cell. In comparison with other materials (e.g., steel) magnesium proved to be far less efficient. This was most probably caused by its brittle fracture failure mode. Conducted tests give insight into mechanical behaviour of magnesium alloy structures under dynamic compression and their ability to absorb energy. Collected data may prove useful for biomedical applications e.g., in designing bone implants.
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Effect of contour laser strategy on the production of gradient lattice structures by SLM technology
Juránek, Štěpán ; Vaverka, Ondřej (referee) ; Jaroš, Jan (advisor)
In this work, the effect of using the contour strategy in the fabrication of gradient micro-lattice structures is investigated. By an experimental method using metallurgical grinding and 3D scanning, the contour strategy is compared with the meander strategy and various phenomena that affect the porosity and dimensional accuracy of the structures are observed. Although the results of both strategies were very similar, the contour strategy proved to be more promising for the fabrication of gradient structures, as is the case for the fabrication of structures with constant diameter.
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Surface roughness of lattice structures produced by SLM technology
Bóssi, Adam ; Malý, Martin (referee) ; Jaroš, Jan (advisor)
Selective laser melting (SLM) is an additive manufacturing technique (AM), that allows production of complex geometries that can be found in lattice structures. Processing of magnesium-based materials with this technology is difficult because of their high reactivity. This bachelor’s thesis clarifies the effects of processing parameters (laser power and laser scan speed) on surface roughness of lattice structures. The theoretical part of this thesis deals with the issue of magnesium alloys and manufacturing of lattice structures. The practical part of this thesis contains the design of the experiment and evaluation of the given experiment. Based on the results of the experiment, the dependencies of process parameters were made on surface roughness and incline angle of struts. The main takeaway of this thesis for the reader is in familiarization with the issue of process parameters and their effect on surface roughness in lattice structures.
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Micro-lattice structures with variable strut diameter
Brulík, Karel ; Jaroš, Jan (referee) ; Červinek, Ondřej (advisor)
Due to their specific properties, micro-lattice structures have a great potential for use in energy absorption applications. It turns out that conventional micro-lattice structures with constant volume fraction can be designed for a known amount of absorbed energy. In real applications, however, we often do not know it in advance. Therefore, the use of functionally graded micro-lattice structures, which can be designed for a wider range of applied energies, appears to be more promising. The aim of this work is to compare micro-lattice structures with variable strut diameter made from 316L stainless steel by Selective Laser Melting technology in terms of energy absorption capability. For this purpose, two types of structures, F2BCC and F2BCC_45, were fabricated, both in configuration with constant, continuously variable and stepwise variable strut diameter. The structures were subsequently dynamically loaded using a drop-weight test, the results of which were described by the time history of deformation and forces. The greater amount of absorbed energy was measured for structures of type F2BCC_45, up to 73 % depending on the configuration of the structures. The results revealed that the variable strut diameter does not have a large effect on the amount of absorbed energy, but it significantly reduces the shock generated, up to 54 % depending on the type and configuration of the structure. This thesis provides a comprehensive view of the deformation and stress characteristics of both types of structures, and in particular a comparison of the effect of variable strut diameter.
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Design of a mechanism for cleaning magnesium welding wire
Seidler, Filip ; Jaroš, Jan (referee) ; Slavíček, Jakub (advisor)
The bachelor's thesis dealt with the design of the mechanism for cleaning magnesium welding wire. In the first part of the work, a research was made for possible solutions and commercially available devices for cleaning wires. The applicability of the individual solutions was subsequently evaluated and, based on the evaluation, a custom solution meeting the specified conditions was proposed. The actual design used the principles resulting from the research of existing and unconventional solutions, which it further develops, thus managing to fulfill the requirements of the main and secondary objectives of the assignment. The design made it possible to remove impurities and corrosion from the surface of the magnesium welding wire meeting the specific conditions of the assignment.
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