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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.
191

Trhání vodního sloupce pod OK vodní turbíny při nestacionárních stavech. / Water column separation under hydraulic turbine runner during unsteady operating regimes.

Vašek, Lubomír January 2012 (has links)
In this diploma thesis called Water column separation under the hydraulic turbine runner during unsteady operating regimes are solved the pressure pulsations of the reverse water hamer. In the thesis is deduced a mathematical relationship of elaboration the numerice model which is based on equations of continuity and equations of forces equilibrium. Numerical model is created in MS Excel uses for computation the numerical method Lax-Wendrof that allows consideration of variable sound speed as function of static pressure and allows variable lenght step in computation domain. Reverse water hammer is in the thesis solved with consideration of rotating flow behind shut-off valve, where we expect forming of vortex rope. This situation can be applied on the closing water turbine which has vertex rope under turbine runner. Specifically for this thesis was carried out the experiment of the reverse water hammer. Constants going into numerical solution are optimalized with using experiment and pressure pulsation are compared between numerical solution and experiment.
192

Úcpávky turbodmychadel / Turbocharger seals

Holík, Petr January 2012 (has links)
This master’s thesis deals with theme of turbocharger seals. The aims of a thesis are to compare a turbocharger seals used in PBS Turbo turbochargers and to describe a testing of a seals. Principle of turbocharging and types of turbocharger are described in fist part. Next point of the thesis is describing of a face seals and non-contacting seals. The main part of the thesis describes kinds and reasons of seals testing; also contains comparison between labyrinth seals and piston ring, comparison of seals of PBS Turbo’s turbochargers and assesses the impact of turbocharger angle on the tightness of the seal.
193

Využití metody konečných prvků pro modelování šíření hlasu vokálním traktem a okolo hlavy člověka / Finite element modelling of voice propagation through the vocal tract and around the human head

Tomeček, Vojtěch January 2013 (has links)
This diploma thesis deals with creating of finite element model for the analysis of acustic waves radiation through human vocal tract and through the head surrounding space. The thesis contains a short overview of the anatomy of relevant parts and a short overview of formerly published models relevant to the topic. Then the process of creating the 3D model of human head, including the vocal tract, based on CT scans, and the mesh itself follows. This is succeeded by the computational solution taking in the acount the acoustic absorption of the vocal tract walls and radiation into the open space. The results gained are compared to relevant literature on this topic. The changes in frequency spectra in specific nodes of the mesh are reviewed and compared to relevant literature on the topic. The results could be used as basis of eventual frequention corrections of microphones used for voice diagnosis or registration in general, eg of speach or singing.
194

Měření napjatosti ve spirále vodní turbíny pomocí tenzometrů / Measurements of the stress in the turbine spiral casing using the strain gauges

Dokoupil, Pavel January 2014 (has links)
The Master‘s thesis is focused on measuring of the stress in the spiral case of water turbine using the strain gauges measurement. It contains the theoretical and the practical part. The theoretical part includes a description of theoretical background (basic mechanics, measurement and evaluation, strain gauges, pressure measurement, uncertainty of measurement). One of the chapters describes Water Power Plant Lipno nad Vltavou (history of power plant, issues and the history of measurement). The practical part contains a theoretical calculation of measurement uncertainty and measuring of stress on spiral case Francis turbine at Water Power Plant Lipno I (Unit TG2). Measurement was made before and after overhaul. There are described technical data of spiral cases, description of measurement, results of measuring of strain and stress including comparison with the pressure in spiral case and calculation of uncertainties of measurement.
195

Modelová studie účinků ultrazvuku na vývoj plodu / Model Study of Ultrasound Effects on Fetal Development

Jaroš, Josef January 2009 (has links)
The progress in ultrasound techniques goes hand in hand with increasing of diagnostic machine acoustic outputs. Ultrasound biological effects can adversely influence the development of human fetus. Recent studies of thermal effect on biological tissues are usually based on simulation of simple ultrasound transducers. The aim of this work is to build a flexible model of diagnostic system to simulate temperature increase during fetal development. Different types of ultrasound probes were used for generation of acoustic field with simulated piezoelectric element properties. Optimized linear and phased arrays were modeled with dynamic beam steering and focus. Computer simulations were concentrated on extreme conditions in obstetric ultrasonography and 3D tissue model was compared with real ultrasound probes measurements. To detect temperature increase, the bone tissue phantom was used. Results point out potential risks for fetus with diagnostic ultrasound probes. Based on the results of this work, practical recommendations increasing safety of obstetric examinations were drawn.
196

Vliv venkovní teploty na vlastnosti výztužné vrstvy při realizaci ETICS / The influence of the outdoor temperature on the properties of the reinforced layer in the implementation of ETICS

Novotný, Michal Unknown Date (has links)
The trend in today's civil engineering are growing demands for quality and comfort constructed buildings and spaces in them. This trend causes a change in the approach to designing buildings and building new buildings. One of the main directions great importance is attached dedicated reconstruction of buildings and their technical adjustments to meet the ever increasing demands being norms and laws. One of the most monitored parameters are thermal-technical characteristics of objects - i.e. better quality means saving on heating costs. In this connection there is a big trend of the modern construction industry and building insulation, mainly ETICS systems. Dissertation focuses on the basic (reinforced) layer of the ETICS and examines the effect of low temperatures, acting on the matter in the implementation of the system, the properties of this layer. This coating is one of the key elements of the system, which more or less determines the quality and durability of the system. The first part deals with the current state of the problem and generally insulation systems, basic types and the advantages and disadvantages of these systems. In the main part of the work is solution focused work, its objectives and methodology for testing materials using laboratory tests and are mentioned outputs of experiments in terms of results. The final section addresses the evaluation of the data and results and output for construction practice. The theme of work was also addressed in the specific research. The works are also numerical and graphical attachments to records of experiments and calculations.
197

Vysokofrekvenční pulsace při provozu vodní turbíny / High Frequency Pulsation of Water Turbine in Operation

Kubálek, Jiří January 2013 (has links)
This thesis is concentrated on mathematical modeling of high frequency pulsations in pump turbines, which are the source of high-cycle continuous stress of the spiral casing cover, wicket gates and runner. There are proposed the solutions using the transfer matrix for the tube with a constant and conical cross-section. The paper compares variations of cylindrical and conical tubes, changes in boundary conditions. There are the models of PSPP Dlouhé Stráně made only of cylindrical tubes comparing to the model with cylindrical and conical tubes
198

Mechanické a elektrické vlastnosti tenkých kovových vrstev nanášených vakuovým napařováním / Mechanical and Electrical Properties of Thin Metal Films Deposited by Vacuum Evaporation

W. F. Yahya, Doaa January 2015 (has links)
Thin layers are widely used in many fields of technology and today we can say that they are found in all modern technologies. Thin layers can be created in two ways, namely by chemical or physical means. This work focuses on the latter method, more particularly a technology of thermal evaporation of thin layers in a vacuum. The work focuses on the process principles during and after the evaporation. Much of the work focuses on the development and design of experiments. These experiments illustrate some of the phenomena that take place on thin films produced by the aforementioned technology. Work helps to better understand processes during formation of thin layers and properties that influence the quality and stability of thin films. In conclusion we describe results of experiments and new developments in the field of thin films deposition using evaporation under vakuum are summarized.
199

Energetický audit vodovodů / Energy Audit od Water Supply Systems

Krupa, Filip January 2016 (has links)
This Disertation deals with energetical audit of aqueduct. First part is dedicated to the current status in Czech Republic, but expecially abroad. Other part processes structure of energetical audit according to the knowledge gained and also from academic articles and set up an example, where this audit is made. Firts variant is energetically intensive water line and other variant is nergetically economical. Last part id dedicated to perform an energetical audit on real water line in Kateřinice village, Vsetín district.
200

Posouzení železobetonové konstrukce bytového domu / The Design of RC Structure of Residential House

Hrvolová, Markéta January 2016 (has links)
The aim of the diploma thesis is static solution of selected parts of the residental house with formwork drawings and reinforcement drawings of designed structures included. Project describes the design and assessment of the monolitic slab structure, precast stair flights, basement loadbearing wall and retaining wall. For calculation of the internal forces was used software Scia Engineer.

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