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Specifications of the Ansys Fluent Solution Solver for low pressures in EREM
Šimík, Marcel ; Bílek, Michal (referee) ; Maxa, Jiří (advisor)
This thesis is focused on electron microscopy which issue is discussed at the beginning of work. The main attention is dedicated to the Environmental electron microscope, especially the differentially pumped chamber, which the thesis deals with. There is a production of an experimental chamber for analysis of shock waves on going therefore main goal of this thesis was to analyze the flow pattern in this chamber. Using the Ansys Fluent program, simulations of the characteristic flow that arises from the pumping of the vacuum chambers namely the ultrasonic flow at low pressures on which the most suitable turbulent module was applied as well as the degree of discretization was performed. The final analysis of this flow pattern is primarily focused on the localization of the shock wave which experimental evidence is to be lodged by shadow optical method as a part of the new concept of the chamber. The basis for the simulation of the chamber was taken over by Dr. Danilatos, with which the results were compared.
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Stress-strain analysis of the thin wall structure subjected to impact load
Tatalák, Adam ; Peč, Michal (referee) ; Návrat, Tomáš (advisor)
This master thesis deals with stress-strain analysis of simplified model of the thin wall transformer case subjected to impact load of electrical blast. Electrical blast is replaced by chemical blast (detonation of high explosive). The problem is solved using computational modeling utilizing the Finite Element Method (FEM) and LS-DYNA solver. After the introduction where detonation and shock wave propagation is explained the analytical approach is presented. This approach serves to results verification. In the next chapter is conducted research of applicable methods from which ALE method is chosen. In preliminary study is performed the mesh size analysis that is focused on finding the size of element which is both computational effective and gives accurate results. Next the infulence of input conditions (shape, location and parametres of high explosive, location of detonation point, boundary conditions) on distribution and time progress of pressure is investigated. Then influence of the opening on upper side of the case on overall pressure redistribution and strain and stress of the case is analysed. The stress-strain analysis of the case´s door which are connected to case by various types of contact models is performed as well as stiffness analysis of these types of contact.
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Launching and Operating Issues of Supersonic Business Jet
Kincová, Daniela ; Veselý, Petr (referee) ; Šošovička, Róbert (advisor)
Tato práce se zabývá problematikou zavedení a provozu nadzvukových business jetů. V dnešní době se v civilní letecké přepravě, po ukončení provozu Concordu, žádná nadzvuková letadla nevyskytují. V dnešní době existuje mnoho projektů a organizací, které se zabývají znovuzavedením nadzvukových letounů do civilního letectví a soustředí se převážně na business jety. Hlavní otázkou je, zda je vůbec vhodné, či rozumné se k tomu typu dopravy znovu vracet. Existuje hodně problémů, které toto komplikují. Tyto letouny způsobují příliš velký hluk, mají obrovskou spotřebu paliva a musí řešit nadměrné emise, létají ve vysokých výškách ve kterých může docházet k problémům s přetlakováním kabiny, navigací, radioaktivním zářením apod. Navíc zákaz supersonických letů nad pevninou letové cesty omezuje a prodlužuje. Současně vznikající projekty navíc nedosahují tak velkého doletu jako klasické moderní bussjety, což způsobuje, že se nadzvukové business jety se na delších tratích stávají neefektivní. I přes tyto problémy, je víceméně jisté, že k zavedení nadzvukových business jetů dojde během následujících 10 - 15 let, i kdyby to měla být jen otázka jisté prestiže velmi bohatých lidí.
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Analysis of the supersonic flow of gas in the differentially pumped chamber EREM
Matloch, Roman ; Vyroubal, Petr (referee) ; Maxa, Jiří (advisor)
This work describes briefly electron microscopy issue and physical model of fluid flow. Then presented diploma thesis will be describing analysis and evaluation of the impact of supersonic flow on the pressure and density in the path of the primary electron beam in the differential pumping chamber. For analysis, evaluation and examination of the issue will be used CAD and CAE (Computer Aided Engineering) programs. At the same time it will be developed a methodology of calculation applicable to supersonic flow in the low pressure system at ANSYS CFX.
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Blast syndrome from the perspective of paramedic
JAVORSKÁ, Andrea
The topic of this bachelor thesis is: "Blast Syndrome from the Perspective of a Paramedic". The thesis consists of a theoretical and practical part. In the theoretical part of the thesis, I focus on the description of the term blast syndrome and the terms of its origin. I also describe the procedures connected to the blast syndrome in not only pre-hospital medical care but also hospital care. I believe that the first aid is equally important and therefore I mention its most crucial elements in the theoretical part of the thesis. The theoretical part also contains a description of the connection between the surroundings and the spreading of a shock wave and the impact of the shock wave on particular body organs. The goal of the bachelor thesis is to examine the knowledge of paramedics concerning blast syndrome. To achieve this goal, three research questions were set down. The research section was elaborated with the use of qualitative inquiry based on semi-structured interviews consisting of fifteen questions. The inquiry assemblage consisted of twelve paramedics. The results of the inquiry show that the paramedics have a basic knowledge of blast syndrome. The respondents were able to explain what a blast syndrome is and how it originates. They also know what injuries they may expect when responding to the patient with blast syndrome and which procedures they have to perform. The data analysis also showed an insufficient theoretical and practical training of paramedics concerning the blast syndrome provided by the employer. This bachelor thesis may serve as study material for students of the paramedic study programme; and also for paramedics already in the field, as a source of information about blast syndrome.
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Comparison of the effects of manual techniques and radial shock wave in the area of the myofascial trigger point.
Bohatý, Pavel ; Malá, Jitka (advisor) ; Vomáčková, Helena (referee)
Author: Bc. Pavel Bohatý Title: Comparison of the effects of manual techniques and radial shock waves in the area of the myofascial trigger point. Objectives: The main focus of this thesis is to compare the effect of treatment using radial shock wave and selected manual techniques. Methods: In this diploma thesis, the Wagner FDIX Force digital pressure algometer was first used to evaluate the effectiveness of both experimental methods to examine the pressure pain threshold, then a Visual Analogue Scale for pain and a two-arm goniometer to examine range of motion to the lateroflexion of cervical spine to opposite side from the occurring MTrp. The outcome data was stored in Microsoft Excel 365. Basic descriptive statistic was used for data analysis using mean values, medians, standard deviations, etc. Due to the heterogeneity of input values in both groups, a regression model and nonparametric Mann-Whitney U-test was used. The significance level for statistical tests was set at α = 0.05. Results: A total of 31 probands were involved in the research, of which 16 underwent radial shock wave therapy and 15 using manual techniques. A statistically significant improvement was measured in the group undergoing radial shock wave therapy in the examination of the pressure pain threshold at the 1st session (by...
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Phosphine and nitrous oxide as false-positive biosignature gases in planetary spectra
Kaiserová, Tereza ; Ferus, Martin (advisor) ; Kopecký, Vladimír (referee)
5 Abstract This study is dedicated to evaluating the potential for a novel pathway of abiotic synthesis of phosphine (PH3) from phosphorus trioxide (P4O6) by a photocatalytic mechanism on aerosols. The mechanism might explain the recent possible detection of phosphine on Venus. This scenario has recently been suggested theoretically by our team based on an analogy with methane production form carbon dioxide on acidic photochemically-active surfaces of materials, which may account for a possible source of methane on Mars. Methane, just like phosphine, was suggested as an indicator of life on terrestrial planets, including Mars. The theoretical testing of photochemical phosphine generation suggests that even if this gas is present in the atmosphere of Venus it cannot be considered as an indicator of life until the suggested mechanism is excluded theoretically, or by experimental results, or direct evidence of life on Venus. This thesis will be followed by preparation of sophisticated experiments and intensive laboratory research addressing this. Furthermore, the role of nitrous oxide as another false positive biosignature was evaluated in this study. The presence of nitrous oxide can also be explained by processes other than biological, particularly on early planets. This study specifically demonstrates the...
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Shock waves in ducts
Luxa, Martin
The report deals with shock waves in ducts, which originate as a consequence of sudden closing of quick acting valve. Three methods of solving are described. Selected actual problems of czech power plants are solved.
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The Imaging Of A Schock Wave Within A Supersoniclow-Pressure Gas Flow Using Opticalmethods
Bayer, Robert
Using Environmental Scanning Electron Microscope (ESEM), which uses high gas pressure within the specimen chamber instead of vacuum, allows us to study samples containing water, samples with high capacity and live biological samples. It is because of the lack of the need to freeze the sample to sublimate the water from it. However, the behavior of the pumped gas in low pressures is not well mapped to be the low-pressure gas flow simulations considered adequately precise for applying on ESEM. To increase the precision of simulations, it is possible to use optical methods for imaging the shock wave within the differentially pumped chamber because of its uniqueness.
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The Impact Of Critical Flow In Differentially Pumped Chamber
Hlavatá, Pavla
Environmentální rastrovací elektronový mikroskop (EREM), který je konstruován pro vysoký tlak plynů v komoře vzorku namísto vakua, umožňuje studovat vzorky obsahující vodu nebo živé biologické vzorky bez nutnosti jejich speciální úpravy. To z důvodu, že mezi komoru vzorku a tubus je vložena diferenciálně čerpaná komora. Vzhledem k velkým tlakovým spádům u této konstrukce dochází při čerpání plynu k nadzvukovému proudění za clonou oddělující komoru vzorku od diferenciálně čerpané komory. To se projevuje specifickým jevem kritického proudění ve cloně a poklesem tlaku v proudu v nadzvukové oblasti. Vhodnou konstrukční úpravou je možné využít daný jev a docílit snížení průměrného tlaku plynu ve dráze primárního svazku. To má za následek snížení rozptylu primárního svazku a zvýšení ostrosti výsledného obrazu.
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