National Repository of Grey Literature 11 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Verification of the properties crimp joint
Horák, Ondřej ; Hruška, Ondřej (referee) ; Lidmila, Zdeněk (advisor)
The bachelor thesis deals with the description of mechanically unbreakable conections, called crimp connection. The most often used materials are copper, brass and bronze. The crimp connections are divided into joints with an open tube, closed tube and crimp isolation. The joint is formed by bending of the parties of the crimp, where a consequent plastic deformation results in a mechanically non-detachable joint. The post production control of the crimp consists of visual inspection, measure of the crimp height, supplementary tearing test and cutting the crimp. No visual defect in testing two types of crimp connections was detected. The measured crimp height corresponds to the values specified by the manufacturer. During the tear test, the desired values were not achieved by incorrectly attaching the wire to the clamping mechanism and no manufacturing defects were detected at the final check of the cut.
Media analysis of the coverage of the event by the Czech and Slovak main TV news: Shooting attack in Bratislava on 12 October 2022
Hruška, Ondřej ; Jirků, Jan (advisor) ; Schneiderová, Soňa (referee)
The master thesis entitled Media analysis of the coverage of the event by Czech and Slovak main news TV channels: Shooting attack in Bratislava on 12 October 2022 examines the media coverage of the terrorist attack that took place in October 2022 in Slovakia. The theoretical part defines concepts such as reality, objectivity and agenda setting. A large part consists of a discussion of the specifics of television news coverage, which is the subject of our work. The media coverage of the event that this thesis examines raises a number of ethical issues, which is why the theoretical part deals not least with journalistic ethics. The practical part initially introduces the shooting attack in Bratislava in more detail and the objectives of this media analysis. It then focuses on the methodology of each research question, introduces the media studied and then presents the results for each of the research questions. The main aim of the thesis is to find out how different the media coverage of this event was, both on individual TV stations and between countries. In doing so, the focus was on mapping the evolution of media discourse on the topic, analysing the frames offered of the event or the position of the topic in relation to other stories in the main news coverage. Special attention was paid to...
Smartphones in education
Hruška, Ondřej ; Vaňková, Petra (advisor) ; Leipert, Jiří (referee)
Modern technology has become an integral part of our life but its implementation into school education is not so fast. Most of the population own a smartphone. While some people say that smartphones should be used in the lessons, others would prefer a partial or complete ban on them in schools. This work summarizes strengths and weaknesses of smartphones in education based on the literature review and discusses some recommendations on their use. Use of smartphones in education was studied in an application which helped with the basics of Russian alphabet. It was shown that most of the users did not read license terms, preferred their own gender for application voice and tended to leave the application prematurely. The users from primary and secondary schools seemed to prefer to use the application more at weekends than on working days, and the application was willingly installed more by older users. A questionnaire survey at a school was used to grasp the whole topic. It was revealed that that touch devices would be welcome in education by students, and they were prepared to use their own smartphone for studying, but at school rather than in their free time. Mobile phone is the preferred device for games playing and internet browsing, but the most used applications include social networks,...
Classical limit of relativistic dynamical fields
Hruška, Ondřej ; Podolský, Jiří (advisor) ; Svítek, Otakar (referee)
In this work, we summarise existing results concerning the absence of "gravitational aberration" in Einstein's general theory of relativity, i.e., the fact that the gravitational "force" points towards the instantaneous position of objects with mass, although the field propagates at the speed of light. The electromagne- tic interaction behaves similarly. Thanks to that, the classical limit with infinite speed of propagation of electricity and gravitation is a good approximation of relativistic fields. We use the Liénard-Wiechert potentials to compute the corre- sponding electric field, and the Christoffel symbols calculated from the metric of so-called photon rocket to determine the gravitational acceleration. We analyse the magnitude and direction of the interaction in both cases. Our own contri- bution is an attempt to interpret the direction of gravitation interaction in the context of de Sitter universe with non-zero cosmological constant.
The study of exact spacetimes with a cosmological constant
Hruška, Ondřej ; Podolský, Jiří (advisor)
In this work we investigate an exact solution of Einstein's equations which is described by the Pleba'nski-Demia'nski metric. This metric represents type D space-times and contains seven free parameters, including electric and magnetic charges and a cosmological constant. We study geometrical and phy- sical properties of these space-times in the case when repeated principal null congruences have zero expansion. Therefore, first we study de Sitter universe and anti-de Sitter universe in the Pleba'nski-Demia'nski coordinates, and we care- fully analyze the corresponding parametrizations of (anti-)de Sitter hyperboloid in five-dimensional flat space-time, unknown so far, we draw the respective con- formal diagrams, and we find transformations to various known forms. After that, we investigate the more general case of the B metrics with a cosmological con- stant, and we do a basic analysis of its geometrical properties. We summarize the article by Gott from 1974, where he interprets the BI metric as a part of space-time with a tachyon singularity, and we generalize his results for the case of non-zero cosmological constant. Finally, we analyze even more general cases of the Pleba'nski-Demia'nski metric with more non-zero parameters. In particular, we study the electromagnetic field in the case of non-zero...
Smartphones in education
Hruška, Ondřej ; Neumajer, Ondřej (advisor) ; Jeřábek, Tomáš (referee)
Modern technology has become an integral part of our life. Schools are often conservative, so involvement of technology in education is delayed. Most of the population own a smartphone, and while some people say that smartphones should be used in the lessons, others would prefer a complete ban on them. This work sums up strengths and weaknesses of smartphones in education based on literature and discusses some recommendations on their use. Smartphones usage in education was studied in an application which helps with basics of Russian alphabet. It was shown that majority of the users did not read license terms, preferred the same sex for application voice and tended to leave the application prematurely. A questionnaire survey on a school was used to grasp the whole topic. It was revealed that that touch devices would be welcome in education by students, and they are prepared to use their own smartphone for studying although rather at school than in their free time. Mobile phone is the preferred device for games playing and internet browsing but the most commonly used applications include social networks, communication programs and video players. It seems that the worst school results are achieved by students who use the smartphones most, but best results are not achieved by students who use the phone the least.
Investigation of geometrical and physical properties of exact spacetimes
Hruška, Ondřej ; Podolský, Jiří (advisor) ; Pravda, Vojtěch (referee) ; Steinbauer, Roland (referee)
In this work, we study geometrical and physical properties of exact spacetimes that belong to non-expanding Pleba'nski-Demia'nski class. It is a family of solutions of type D that also belong to the Kundt class, and contain seven arbitrary parameters including a cosmological constant. We present here the results of three extensive articles, each focusing on a different aspect of the problem. In the first article, we investigate the meaning of individual parame- ters in the non-expanding Pleba'nski-Demia'nski metric. First, we set almost all parameters to zero and obtain Minkowski and (anti-)de Sitter backgrounds. Af- terwards, we allow other parameters to be non-zero and we study the B-metrics, non-singular "anti-NUT" solutions and conclude with the full electrovacuum Pleba'nski-Demia'nski metric. In the second article, we focus on the de Sitter and anti-de Sitter backgrounds where we present and analyse 11 new diagonal metric forms of (anti-)de Sitter spacetime. We find five-dimensional parametriza- tions, draw coordinate surfaces and conformal diagrams. In the third article, we show that the AII-metric together with the BI-metric describes gravitational field around a tachyon on both Minkowski and (anti-)de Sitter backgrounds. Fi- nally, in order to better understand the global structure and...
Verification of the properties crimp joint
Horák, Ondřej ; Hruška, Ondřej (referee) ; Lidmila, Zdeněk (advisor)
The bachelor thesis deals with the description of mechanically unbreakable conections, called crimp connection. The most often used materials are copper, brass and bronze. The crimp connections are divided into joints with an open tube, closed tube and crimp isolation. The joint is formed by bending of the parties of the crimp, where a consequent plastic deformation results in a mechanically non-detachable joint. The post production control of the crimp consists of visual inspection, measure of the crimp height, supplementary tearing test and cutting the crimp. No visual defect in testing two types of crimp connections was detected. The measured crimp height corresponds to the values specified by the manufacturer. During the tear test, the desired values were not achieved by incorrectly attaching the wire to the clamping mechanism and no manufacturing defects were detected at the final check of the cut.
The study of exact spacetimes with a cosmological constant
Hruška, Ondřej ; Podolský, Jiří (advisor)
In this work we investigate an exact solution of Einstein's equations which is described by the Pleba'nski-Demia'nski metric. This metric represents type D space-times and contains seven free parameters, including electric and magnetic charges and a cosmological constant. We study geometrical and phy- sical properties of these space-times in the case when repeated principal null congruences have zero expansion. Therefore, first we study de Sitter universe and anti-de Sitter universe in the Pleba'nski-Demia'nski coordinates, and we care- fully analyze the corresponding parametrizations of (anti-)de Sitter hyperboloid in five-dimensional flat space-time, unknown so far, we draw the respective con- formal diagrams, and we find transformations to various known forms. After that, we investigate the more general case of the B metrics with a cosmological con- stant, and we do a basic analysis of its geometrical properties. We summarize the article by Gott from 1974, where he interprets the BI metric as a part of space-time with a tachyon singularity, and we generalize his results for the case of non-zero cosmological constant. Finally, we analyze even more general cases of the Pleba'nski-Demia'nski metric with more non-zero parameters. In particular, we study the electromagnetic field in the case of non-zero...
The study of exact spacetimes with a cosmological constant
Hruška, Ondřej ; Podolský, Jiří (advisor) ; Krtouš, Pavel (referee)
In this work we investigate an exact solution of Einstein's equations which is described by the Pleba'nski-Demia'nski metric. This metric represents type D space-times and contains seven free parameters, including electric and magnetic charges and a cosmological constant. We study geometrical and phy- sical properties of these space-times in the case when repeated principal null congruences have zero expansion. Therefore, first we study de Sitter universe and anti-de Sitter universe in the Pleba'nski-Demia'nski coordinates, and we care- fully analyze the corresponding parametrizations of (anti-)de Sitter hyperboloid in five-dimensional flat space-time, unknown so far, we draw the respective con- formal diagrams, and we find transformations to various known forms. After that, we investigate the more general case of the B metrics with a cosmological con- stant, and we do a basic analysis of its geometrical properties. We summarize the article by Gott from 1974, where he interprets the BI metric as a part of space-time with a tachyon singularity, and we generalize his results for the case of non-zero cosmological constant. Finally, we analyze even more general cases of the Pleba'nski-Demia'nski metric with more non-zero parameters. In particular, we study the electromagnetic field in the case of non-zero...

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