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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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Buildings of the representative offices of Czechoslovakia during the interwar period; strategy of their selection and acquirement
Jaroš, Jan ; Čechurová, Jana (advisor) ; Kuklík jun., Jan (referee)
Czechoslovak Embassy and Consulate Buildings During the Inter-war Period: Selection and Acquisition Strategies In the Diplomatic Service of Austro-Hungarian empíre worked only few Czechs and Slovaks. For this reason the new established Czechoslovakia had to educate many diplomats and also to create its own network of embassies and consulates. This involved also the buildings. When choosing the right estates were above all important the following factors: representativness, security and costs. Own buildings provided better presentation opportunities and it was easier to adapt them for diplomatic function. Thanks to the stability of Czech currency in the interwar period were the costs for the buildings reasonable. For building, adaptations and equipping the buildings was used stable group of professionals. The critisism of purchase of some particular objects and its equipment was mostly sourcing from the relationships among some diplomats and political situation in Czechoslovakia. Czechoslovakia had its own buildings, which were used as embassies, consulates or official apartments of ambassadors or consuls, in this important cities or capitals of European states (in alphabetical order): Ankara, Belgrade, Berlín, Bern, Budapest, Bucharest, Galati, Hague, Hamburg, London, Paris, Rome, Sofia, Tirana ( only the...
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Unauthorized Disposal of Personal data
Jaroš, Ján ; Vokoun, Rudolf (advisor) ; Říha, Jiří (referee)
The submitted rigorous thesis deals with the unauthorized use of personal data in the Czech criminal law. The thesis particularly focuses on the interpretation of the concept of personal data, the processing of personal data, the criminal offense, the principle of subsidiarity criminal repression and further on the research of two conflicting rights too - the right to protection of information (personal data) and the right to information. The complexity and legal uncertainty is primarily caused by judicial practice, which is in the interpretation of individual terms inconsistent, although professional literature and the public point of view on the interpretation of so-called "borderline cases" is unified. Amendment to the Acts, the Criminal Code and related laws, do not always solve problem areas ideally" and therefore opinions issued by "bodies active in criminal proceedings" and administrative authorities contribute to the unification of procedures and interpretations. The rigorous thesis also focuses on the application of the "ultima ratio" which should be taken into account in decision making if a crime or an offense was committed. Unless the facts of the crime and the offense not met the rule of law offers a number of means, which the defective condition, that involves unauthorized processing...
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Funding of churches in the Czech lands in 20th century
Jaroš, Ján ; Tretera, Jiří Rajmund (advisor) ; Horák, Záboj (referee)
Financing of Churches in the Czech Lands in the 20th Century The main aim and purpose of this master degree thesis was to introduce individual institutes of the Church financing in the 20th century. Even nowadays, the funding issue is still an opened topic. The purpose of the historical hindsight is to approximate and put aside false hypothesis of Church financing. The prevailing views of the people on the church property and on the "justification" of states occupation of this property, during the last century, were based on rather "philosophical ideas" than on actual legal basis. The master degree thesis not only maps the 20th century, but also pays due attention to the developments of the late 19th century, which established grounds for certain financing institutes and prefigured further evolvement in the upcoming century. However, some institutes of church financing, such as religious fund, were established in the 18th century. The period of enlightened absolutism, the period of the reign of Joseph II, who brings his mothers reforms to the edge of that time, sells property (e.g. monasteries, religious buildings, etc.) and the obtained income deposits to newly created parish cash desk, which will serve to support the Catholic Church. Indeed, the income from the religious funds became one of the main and...
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Selected Psychological Aspects of Mediation
Jaroš, Jan ; Höschlová, Eva (advisor) ; Gillernová, Ilona (referee)
The bachelor thesis focuses on description and analysis of psychological aspects present in the mediation process which is recognized as a form of interpersonal conflict solution process. Mediation is described as one of the applied psychological disciplines and in this regard it is compared to some of traditional examples. The main part of the thesis consists of theoretical description and analysis of specific psychological aspects of mediation. The following part consists of a research project design, that proposes experimental verification of the psychological aspects influence on the mediation process. The objective of the thesis is to recognize mediation as an applied psychological discipline and to introduce the basic psychological aspects of the mediation process, that need to be acknowledged by the mediation professionals.
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Diagnostic methods of measuring empathy with focus on Czech adaptation of A Questionnare of Cognitive and Affective Empathy
Bartoš, Josef ; Höschlová, Eva (advisor) ; Jaroš, Jan (referee)
The ability to identify yourself with others, or to understand their emotional states, is one of the fundamental strategies of everyday life. This presented thesis is focused on the theme of empathy and psychodiagnostic potential for measuring it. For this purpose, the author presents an initial theoretical framework, the current notion of empathy based upon multidimensional model. He then shows existing inventories and discusses the Questionnaire of Cognitive and Affective Empathy in a greater detail. The aim of the empirical part is to translate this questionnaire, and to verify its psychometric qualities on the Czech population. The sample consisted of 260 participants (57,7% of women), average age was 30,73 years and standard deviation 9,6 years. To carry on the research, the inventory was parallelly translated by three professionals. The research then investigated the five-factor model through confirmatory factor analysis. The results show that the five-factor model fits the Czech data quite well. Nonetheless, five items had to be excluded due to poor factor loadings (3 from factor online simulation, 1 from factor proximal responsivity, 1 from factor peripheral responsivity); the original 31-item questionnaire has its Czech version with 26 items only. Reliability of internal consistency was...
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