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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Vliv inhalačních a intravenózních anestetik na odolnost srdečního svalu k nedostatku kyslíku / Cardiac tolerance to oxygen deprivation: the effects of inhalational and intravenous anesthetics

Říha, Hynek January 2012 (has links)
Background: Surgical procedures are invariably accompanied by the use of inhalational and intravenous anesthetics. Both groups have strong influence on cardiovascular system by the interaction with myocardial oxygen supply/demand ratio and cardiomyocyte functions at the level of cell membranes, ion channels and regulatory enzymes. Aims: 1. To examine the effects of different isoflurane concentrations on the left ventricular (LV) dimensions and systolic function in the rat. 2. To examine the effects of isoflurane-induced myocardial preconditioning (APC) on the cardiac tolerance to ischemia- reperfusion (I-R) injury. 3. To compare the influence of anesthesia, based on ketamine- dexmedetomidine (KET-DEX), on the release of biochemical markers of myocardial injury and the early postoperative course with the anesthesia, based on sevoflurane-sufentanil (SEVO), in the patients undergoing coronary artery bypass grafting (CABG). Methods: 1. We carried out transthoracic echocardiographic examination in the rats immobilized by 1.5-3% concentration of isoflurane. 2. After inducing APC by isoflurane (0.5 and 1 MAC), we evaluated ventricular arrhythmias during regional ischemia (45 min), induced by the occlusion of the left anterior descending artery, and subsequent reperfusion (60 min), using the model of...
102

Environmentálně-psychologická východiska výchovy v přírodě / The Basis of Environmental Psychology for Outdoor Education (The Influence of Nature on Mental and Social Well-Being)

VRBOVÁ, Zuzana January 2012 (has links)
The work deals with theoretical research of basis of Environmental Psychology for Outdoor Education. It answers two questions ? why in the conceptions of Outdoor Education is nature the preferred environment and what are the benefits of nature for physical, mental and social health. The answers to theses questions are in the work described through theories of environmental preference and restorative effects of nature. There are three major sections of the work. The first part discusses the basis, principles and contents of Environmental Psychology and Outdoor Education, the core terminology of the work, and the nodal points of Environmental Psyhcology and the theory of Outdoor Education. Second part describes those theories and concepts of Environmental Psychology which are related to the primary and subsidiary research questions. The third part evaluates the impacts and relevance of environmental-psychological knowledge on concepts of Outdoor Education.
103

Negativní aspekty nasazování ICT / Negative aspects of deploying of ICT

Weinsteinová, Adéla January 2013 (has links)
This diploma thesis exmines the negative aspects of using information and communication technologies. The main attention is fosused on virtual reality, especially 3D projection in order to decide wheather the using of it has negative impact on phycal and psychological state of the user or not, which exactly are these impacts and what probably cause them. This first part is dedicated to expain concept and history of ICT, explonation of the multidimensional princip and content of each dimension. The following is determination of which ICT areas are currently struggling in their use with negative effects. Detected list of these areas is reduced to six specific technologies which common user has opportunities to experience. These particular technologies were examined as a form of questionnaire, which resulted in a determination of the most used one, ie virtual reality. Shortly afterwards was conducted an experiment imparting undesirable effects caused by using virtual reality. The other five selected technologies are discussed for the most important negatives with which has to face today. The main finding of this study is the identification the side effects of virtual reality based on different types of technologies which are anaglyf 3D projection, passive 3D projection, active 3D projection and comparing if adverse effects depends on the type. It also includes determining the rate of uptake in virtual reality.
104

Železobetonová základová vana administrativní budovy / Reinforced concrete foundation tank of office building

Turek, Jan January 2020 (has links)
The master’s thesis deals with a design of a reinforced concrete foundation of multi-storey office building. The basement of the building is an underground watertight structure. The design of foundations is a combination of a concrete slab and piles. Internal forces were analysed in RFEM software based on finite element method. The structural assessment of underground construction was performed according to ultimate and serviceability limit states. Due to watertight function of construction, the reinforcement was also designed according to non-force effect in early stage.
105

Analýza účinků zkratového proudu v rozváděči / Analysis of effects of short-circuit current in switchgear cabinet

Prokop, Jan January 2015 (has links)
The work is focusing on dynamic effects of short-circuit currents, more precisely dynamic effects of short-circuit currents on switchgear cabinet (terminal box). The work was designated to a concrete construction type of two switchgear cabinets located on rotating machines via company Siemens Electric Machines Drásov s.r.o.. The switchgear cabinets are designed for non-explosive environment where the air is used as an insulating medium. The task was to determine how the device will behave during the three-phase short-circuit and three-phase short-circuit with earth/ground connection. The following programs were used for the calculations and simulations: Ansoft Maxwell 16.0, Ansoft Maxwell 2015 and ANSYS Workbench 16.0. By using these programs the effects of forces which acts on current paths in cabinet caused by the passage of short-circuit current were simulated, statically and also dynamically. Further the effects of pressure acting on cabinet frame during the arc short-circuit have been statically and dynamically simulated. All the results are summarized in the conclusion. Conclusion also contains the final evaluation of the functionality of both switchgear cabinets.
106

Analýza mechanického namáhání při zkratu ve vzduchem izolovaném rozváděči vn / Analysis of Mechanical Stress during Short Circuit in an Air-Insulated MV Switchgear

Bártů, Jan January 2017 (has links)
This Master thesis is based on problems of force effects of the magnetic field of short-circuit current. Firstly, I analysed the force action of the three phase busbars during the three-pole short circuit. The analysis was performed in the Ansys Maxwell program and I verified the correctness of the analysis by numerical calculation. The second practical part was executed for ABB company. The main task was to analyse the force effects of the short-circuit current in the HV switchgear with focusing on the arms and contact system of the circuit breaker. The simulations of the following configurations were performed in more details: three configurations of the simplified VD4 circuit breaker, two types of VD4 circuit-breaker contact systems and a linear circuit breaker configuration model. The objective was to calculate the forces acting on the current path of the arms and contact system of the VD4 circuit breaker during the three-phase short-circuit and to simulate the effects of forces on these current parts. For modelling of individual assemblies, calculations and simulations I used: SolidWorks 2014, Ansys Maxwell 16.0 and Ansys Workbench 14.5 programs. With SolidWorks 2014 3D CAD software were modelled simplified assemblies of circuit breakers and contact systems. These systems were imported into the Ansys Maxwell software, where the force effects of the magnetic field of the short-circuit current were calculated. In Ansys Workbench programme was simulated the effect of forces on the current circuit breakers. Moreover, the final deformations of the materials (with respect to the mechanical properties of the structure) were plotted. The analysis of force effects of the magnetic field was performed for the specified static short - circuit current value.
107

Fluid-Structure Interaction between Structural Components of Hydraulic Turbine and Fluid Flow / Fluid-Structure Interaction between Structural Components of Hydraulic Turbine and Fluid Flow

Havlásek, Michal January 2021 (has links)
Tato dizertační práce se zabývá dvěma případy interakce tělesa s tekutinou (FSI). První z nich se zabývá analýzou vzájemné interakce mezi rotorem čerpadla a kapalinou uvnitř těsnící spáry. Vliv těsnící spáry na dynamiku celého stoje je popsán pomocí dynamických parametrů, které jsou také označovaný jako přídavné účinky. V současnosti používané modely těsnících spár používají pro stanovení dynamických parametrů řadu zjednodušujících předpokladů. V této práci je prezentováno pět různých analýz dynamických parametrů těsnící spáry čerpadla na okysličovadlo. Každá z těchto pěti analýz používá jinou míru zjednodušení výpočetního modelu. V případě největšího zjednodušení je modelován pouze objem kapaliny uvnitř těsnící spáry. Nejkomplexnější analýza pro stanovení dynamických parametrů těsnící spáry používá pro výpočet model celého čerpadla s excentrickou polohou rotoru. Druhá část této dizertační práce definuje novou metodu pro řešení interakce kapaliny s pružným tělesem. Tato metoda využívá řešení inverzního problému kmitání. Přímý problém kmitání, který je také označován jako problém vlastních hodnot, používá jako vstupy pro řešení matice hmotnosti, tuhosti a tlumení, které jsou dohromady označovány jako koeficientové matice, na základě kterých je v nejobecnějším případě stanovena Jordanovská matice a také modální matice pravostranných a levostranných vlastních vektorů. Při řešení inverzního problému kmitání jsou stanoveny koeficientové matice na základě Jordanovské matice a modálních matic pravostranných a levostranných vlastních vektorů. Existují dva případy inverzního problému kmitání. V případě, že jsou známy všechny vstupní vlastní čísla a vlastní vektory, pak se jedná o tzv. plný problém. Naopak v případě, že alespoň 1 mód kmitání soustavy není znám, tak se jedná o tzv. částečný problém. V této práci je prezentováno 5 algoritmů pro řešení inverzního problému v kmitání. Nicméně pro každý typ inverzního problému kmitání je prezentován jeden univerzální algoritmus. Algoritmus pro řešení plných problémů byl poprvé prezentován v roce 1979 Otakarem Daňkem. Algoritmy pro řešení částečných problémů, které jsou prezentovány v této práci, jsou vůbec prvními algoritmy pro řešení tohoto typu inverzního problému kmitání. Univerzální algoritmus pro řešení částečných problémů je označován jako algoritmus pro řešení částečných problémů s volbou doplňkových vlastních hodnot. Aplikace těchto dvou univerzálních algoritmů pro řešení inverzního problému kmitání pro případ plných i částečných problémů je ukázána na řešení dvou případů interakce pružného tělesa s kapalinou.

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