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Verification of the Exploitation Possibility of Tensile Strain during the Hopkinson´s Test
Dohnal, Ivo ; Spišák,, Emil (referee) ; Buchar, Jaroslav (referee) ; Forejt, Milan (advisor)
The PhD thesis deals with the possibility of performing dynamic tensile tests. For this purpose, Split Hopkinson Pressure Bar Test (hereinafter SHPBT) is used. The basic construction of SHPBT device is designed to perform dynamic compression tests on materials (metals, plastics, and ceramics). The obtained results are deformation stress – strain and strain rate – strain dependences. SHPBT is capable of testing materials at high strain rates up to 10^2 – 10^3 s-1. It was created a special device for dynamic tensile tests of materials at high strain rates. The created device uses the basic construction of SHPBT. The special device is used for testing flat specimens with 2 mm thickness. It was recognized by the Industrial Property Office of the Czech Republic as a utility model with number 23703. The specimens used for dynamic tensile testing were made of austenitic stainless steel (WNr. 1.4301) with 2 mm thickness. The verification of created device was carried out by numerical simulation. The numerical simulation was performed by ANSYS LS – Dyna software.
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The Project Selected Leisure Time Activities for Children
Křivánková, Renata ; Buchar, Jaroslav (referee) ; Kysel, Jiří (advisor)
Aim of the thesis was to design leisure time activities for 6-14 years old children under Centre for Sport Activities, Brno University of Technology (CESA VUT). Three sport courses – tennis, athletics and ball games were suggested and thein content as well as propagation outlined. Membership fee was calculated using cost analysis together with analysis of competive environment in similar sport activities in Brno.
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Determination of stress wave pulse attenuation in chocolate with different sample thickness
Buchar, Jaroslav ; Trnka, Jan ; Kober, Jan
The report presents the results of an analysis of the attenuation of a mechanical pulse in samples of five types of chocolate, where each type had five different thicknesses. These are data established on the basis of an economic contract between the Institute of Thermomechanics of the Academy of Sciences of the Czech Republic and the Mendel University in Brno. The chocolate samples were loaded using both the Split Hopkinson Pressure Bar (SHPB) and the Hopkinson measuring split bar direct loading method. The measurement results are processed in the time and frequency domains.
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Determination of mechanical properties of chocolate under impact loading
Buchar, Jaroslav ; Trnka, Jan ; Kober, Jan
The report based on the Economic Contract No. 5/2021 with the MU in Brno and contains the results of research of the deformation behavior of five types of chocolate when loaded with high strain rates of the order 103 s-1. Two methods were used in the research, the Split Hopkinson Pressure Bar method (SHPB) and the modified Hopkinson bar method, where higher deformation rates can be achieved. Attention is also focused to the fracture behavior of chocolate under dynamic tensile loading. This method of loading is based on the SHPB method using the arrangement of the so-called Brazilian test. In this research, high-speed cinematography was also used to study the formation and development of the fracture of the chocolate sample. The measurement results are processed in the time and frequency domains.
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Flatworms (Platyhelmintes: Tricladida) in the Czech Republik
Reslová, Marie ; Juřičková, Lucie (advisor) ; Buchar, Jan (referee)
This work focuses on the freshwater triclads and summarizes information about species occurring in the Czech Republic. Particular chapters concerned generally with taxonomy, anatomy and ecology of triclads; morphology, ecology and occurrence of each species is discussed in detail. 17 triclad species were recorded in the Czech Republic before now, some of them are considered as endemics. The majority of common triclads is determinable according to the head shape, but determination of Dugesia lugubris, D. polychroa a Polycelis nigra, P. tenuis is possible only based on the penis morphology. Some species can be regard as bioindicators, because of their narrow ecological requirements: cold water with high content of O2 - Dugesia gonocephala, Crenobia alpina, Polycelis felina; higher concentration of Ca2+ - D. gonocephala, Phagocata vitta, Planaria torva; oligotrophic standing waters - Polycelis nigra; eutrophic standing waters - Dugesia polychroa, Polycelis tenuis. Species of underground waters and springs are interesting and still unexplored ecological group of triclads.
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Load Balancing in Evaluation Systems for Programming Assignments
Buchar, Jan ; Kruliš, Martin (advisor) ; Tůma, Petr (referee)
Systems for automated evaluation of assignments are a valuable aid for both teachers of programming courses and their students. The objective of this thesis is to examine the possibilities of deploying such systems in a large-scale distributed environment and the challenges of such endeavors. A sizable part of the requirements comes from experience with ReCodEx - an assignment evaluation system developed at the department of the supervisor. Modern server multi-core processors provide considerable computing power that can be used for assignment evaluation. However, parallel measurements can interfere with each other. This causes unstable results, which detriments the fairness of grading. Isolation (sandboxing) technologies can cause similar effects. We measure both of these influences and use the results to determine to what degree can multi-core processors be exploited. The problem of efficient distribution of work between multiple evaluation workers is complementary to that of utilizing multi-core machines. We survey scheduling algorithms and design an experiment to compare their performance. Additionally, we examine the possibility of leveraging container technologies to simplify the deployment of software required for evaluation. This leads to both a smaller administration overhead and a less complex...
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HelenOS packet filter
Buchar, Jan ; Děcký, Martin (advisor) ; Horký, Vojtěch (referee)
Packet filtering is an essential feature of any operating system that aims to function as a network router or gateway. This thesis aims to extend the HelenOS operating system to support this functionality. We analyze packet filters present in modern operating systems and implement a HelenOS service that provides a configurable and extendable packet filter. We also modify the HelenOS networking stack so that it allows an arbitrary service to function as a packet filter. We demonstrate the extendability of our implementation on a basic variant of the NAT mechanism. Powered by TCPDF (www.tcpdf.org)
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Usufructuary right of building and other ways of erecting house on the land of another
Buchar, Jan ; Hendrychová, Michaela (advisor) ; Šustek, Petr (referee)
Usufructuary right of building and other ways of erecting house on the land of another The purpose of this thesis is to analyse comprehensively the institute of usufructuary right of building and other ways of erecting house on the land of another. Other legal institutes that can be used to set up home on a foreign land are easements, lease, usufructuary lease, precarious loan and loan for use. The Civil Code, after more than sixty years, is returning to the superficial principle, with which is the usufructuary right of building inherently connected and which represents an exception from that principle. Thesis is divided into four parts. The largest is the first part, which deals with the usufructuary right of building. The second part is devoted to other institutes, which enable the establishment of a house on a foreign land. The third part is the comparison of the usufructuary right of building with other institutes. The fourth part focuses on the usufructuary right of building legislation abroad. The focus of this thesis is in the first part, which consists of nine chapters. The first chapter defines the basic concepts and institutes related to the usufructuary right of building. The second chapter describes the history of the usufructuary right of building. The third to the seventh chapter...
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Modernization of Russian army 2008-2014: consequences for post-Soviet area security.
Buchar, Jan ; Svoboda, Karel (advisor) ; Šír, Jan (referee)
Until 2008, almost two decades since the end of the cold war, Russia still retained old Soviet military structures. Steady opposition by the Russian generals against military modernization and reforms was finally broken in relation with the poor performance of Russian forces during the Russia-Georgian war in 2008. The process of modernization commenced in the following years has important security implications for post-Soviet countries. We could observe the new abilities of the Russian military during the seizure of the Crimean peninsula in 2014. Russian forces had been considered an ineffective institution with outdated military technology where corrupt practices were the rule rather than the exception. As we could see in 2008 Georgia Russian forces depended on numerical superiority and blunt military force. On the other hand during the Crimean events of 2014 the Russian military conducted the whole operation with high level of professionalism, without any bloodshed, and with modern weaponry. This research is based on the theory of neorealism which defines key parameters for performing a military modernization analysis. These include numbers, effectivity and strategy of military forces that help us to determine the current strength and power of each state. Therefore this research focuses on the...
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Sino-Russian Military Cooperation in 2000 - 2008: Limits of Mutual Convergence
Buchar, Jan ; Svoboda, Karel (advisor) ; Horák, Slavomír (referee)
The subject of my bachelor thesis is an analytical study which identifies the limit of Sino-Russian military cooperation in 2000 - 2008. In the following thesis I focus on three forms of military cooperation between these two states which are a) Russian military sales to China, b) a possibility of a Sino-Russian military alliance emergence, and c) cooperation in space-related technologies. Within these three categories I analyse the aims of Sino-Russian cooperation and its limits in 2000 - 2008. In case of Russian military sales to China the thesis are concerned with sales of significant amounts of aerial and maritime products. Denied Chinese demands for the advanced Russian military hardware is the main limitation. In case of a military coalition emergence the Shanghai Cooperation Organisation (SCO) played the crucial role. Under aegis of the SCO several joint military exercises took place. Western observers perceived that as evidence of an emerging military alliance. Both states claimed that neither the SCO nor the military exercises were directed against any third country. The main obstacle in the military alliance creation is that Russia and China consider their relationship with Western states higher than with each other. In case of space-related technologies, that have direct military...
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