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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.
81

Stavební průzkum a diagnostika železobetonové konstrukce / Survey and Diagnostics of Reinforced Concrete Structure

Haloun, Jan January 2020 (has links)
The first part of this diploma thesis is about late and current methods used in Engineering surveys. The theoretical part is focused on description of individual testing methods and their evaluation based on relevant standarts. Detailed description of diagnostic methods is dependent on methods used in a practical part. The practical part is focused on defining of material characteristics of used materials and way of reinforcing of reinforced concrete elements. Based on those defined pieces of information the static recalculation of girder and pile was made.
82

Charakterizace a aplikace mikrovlnného plazmatu pro hojení ran / Characterization and application of microwave plasma on wound healing

Smejkalová, Kateřina January 2020 (has links)
The aim of the Master thesis is the investigation of the influence of microwave discharge for skin wound healing. Microwave discharge used for this work was argon microwave plasma generated by the surface wave and direct vortex torch. The theoretical part is focused on basic information about plasma and processes that occur in plasma discharge under specific conditions. Plasma generates various active particles such as hydroxyl radicals, nitric oxide radicals, excited nitrogen molecules, atomic nitrogen, argon and oxygen. All of these particles together with plasma generated photons are usable in biomedical applications and summary of them is shown in the theoretical part. The experimental part is focused on the comparison of torch discharge and microwave plasma generated surface wave in skin wound healing. The model wounds on laboratory mousses were treated by plasma and wound healing was examined during 3 weeks after the plasma treatment. Both plasma systems showed healing acceleration. Application of torch discharge was proved to be the most effective method in the healing of skin defects. Additionally, determination of active particles was taken by optical emission spectroscopy. Based on these measurements, plasma parameters were determined: electron temparutare, rotational and vibrational temperatures. To determine role of different plasma active species, the treatment of indigo coloured artificial skin model was treated under various conditions by both plasma systems. Results show that the direct interaction between plasma particles is the main effect, role of radiation, only, is more or less negligible. Finally, the plasma vortex system was visualized using fast camera at selected powers and gas flows.
83

Vliv atmosféry na laserovou ablaci materiálů / Impact of the atmosphere on laser ablation of matters

Černá, Svatava January 2020 (has links)
This thesis deals with a general overview of laser-induced breakdown spectroscopy - ablation of material and plasma formation when a change of the surrounding environment occurs. The aim is to establish ideal conditions for improving detection, which is difficult for some elements when the measurement takes place in the ambient atmosphere. This is the reason why we change the ambient conditions, the gas (air, helium, argon) and its pressure. Buffer gases (helium, argon) influence the development of the material ablation and quality of generated plasma. That is why we inspect the changes in the signal according to particular atmospheres (signal change in buffer gases compared to the ambient atmosphere). The first part of the thesis presents the principle and physical nature of laser ablation with a brief search of experiments performed so far for similar purposes. Based on this search we determine conclusions about the influence of buffer gasses and pressure on the detection used gasses. In the second part of the work, the controlled experiment is presented, which consisted of the detection of spectral lines of fluorine and potassium, see chapter 5.6 and molecular transitions of calcium fluoride, see chapter 5.10. In a controlled experiment, we established two assumptions. The first assumption is the influence of the inert gas atmosphere, which should significantly improve the detection of fluorine and potassium compared to the air atmosphere. We confirmed this finding only for the argon atmosphere. In contrast, in the helium atmosphere, the detection of none of the elements improved. The second assumption is the effect of reducing the ambient pressure, which in combination with an inert gas should allow the detection of fluorine even at low concentrations in the sample. We consider the measured glass disk in chapter 5.7 to be such a sample. This assumption is not confirmed, as the increased intensity of the fluorine spectral line does not manifest itself in any way when the pressure in the vacuum chamber decreases. Finally, in chapter 7 from the results of individual parts of the experiment, the most suitable conditions for the future detection of the measured substances were proposed: fluorine, potassium and calcium fluoride molecules.
84

Regulace přítlaku lamelových spojek dvouspojkové převodovky / Engagement Force Control of Multi-plate Clutches of Dual Clutch Gearbox

Horák, Josef January 2020 (has links)
The master’s thesis deals with ways of controlling starting clutches of cars, especially of DQ200 gearbox, which contains dry disc clutches. The introduction describes basic principles of torque transfer and amount of clutch force. Then the description of construction of starting clutches and ways of controlling clutch types mentioned beforehand is given. In the next part of the thesis, wide spectrum of control methods is measured, from which a certain part is selected. This is followed by driving tests and based on driving data, one method of the clutch control is chosen. Then those control methods from narrow selection are tested for acoustic impact in the cabin of the car. In the end the best way of clutch control is selected. The selection based on driving data and acoustic measurement.
85

Stavební průzkum a diagnostika konstrukce / Survey and Diagnostics of Building Construction

Řezáč, David January 2021 (has links)
The diploma thesis deals with the construction and technical survey of a reinforced concrete structure. The theoretical part describes the tested properties of concrete and the methodology of their tests used in the practical part. The practical part is devoted to the diagnosis of the existing structure, which was determined the strength of concrete using core holes, concrete adhesion by tear tests, and reinforcement of reinforced concrete elements of the structure determined by ground-penetrating radar, electromagnetic indicators and additional chopped probes.
86

Vysokohodnotné betony na bázi druhotných surovin / High-performance concretes based on the secondary raw materials

Sáček, Josef January 2008 (has links)
This work is devoted to study of physical-mechanical properties and structure of high performance concretes (HPC) based on portland cement. The attention is focused on possibility of substitution of economic high-cost components of concrete with utilization of secondary raw materials or cheaper components. Properties of raw materials and their influence on whole quality of concrete were tracked by various methods. Mechanical properties of prepared HPC samples were tested especially (compression and flexural strength) with further microscopic study of structure. Isoperibolic calorimetry and X-ray powder diffraction method were also used for concrete characterisation. These methods allowed to determine the influence of raw materials on prepared HPC and to carry out a certain optimization among price and quality of this material.
87

Příměsi ovlivňující tuhnutí portlandského cementu / The admixtures which are influencing setting time of portland cement

Hlaváček, Jaroslav January 2012 (has links)
During the production of concrete is important the careful selection of raw materials. Nowadays, we are trying in the production to minimize the economic burden and to maximize the use of secondary raw materials. This work is focused on the use of secondary raw materials from the energy industry in construction for the preparation of hydraulic binders. As the main raw materials were used different power plant fly ash from fluidized combustion. The composition of these secondary materials is quite different from conventional high-temperature ash, due to mixing with water they solidify and harden. Experiments were performed with three lodge fly ash from electrostatic precipitators of the fluidized combustion and one high-temperature fly ash. This work is focused on the possibility of monitoring the use of these secondary materials in construction, especially when tests were evaluated characteristics of strength and speed of setting and hardening.
88

Meteorologická stanice se vzdáleným přístupem / Meteorological Station with Remote Access

Svoboda, Josef January 2010 (has links)
This thesis discusses design and realization of air temperature, pressure and relative humidity measuring device, transmission of measured data over internet and their presentation on a web site. First chapter introduces reader into principles of measuring air temperature, pressure and relative humidity and various types of sensors used for measuring . Next, the conception of designed system is described. Designed system must accomplish tasks from reading raw data from the sensor up to thein graphical presentation to the internet user. Second and third chapter describes hardware and software design of air temperature, pressure and relative humidity measuring unit. In next part one can find description of software used to transmit measured data over internet and software for generating web pages which are shown to users. The work is revieved in the final part of this thesis.
89

Vliv turbulentního modelu na simulace proudění vzduchu v okolí průtokoměru / Effect of the turbulence model for simulation of air flow around flowmeter

Vlček, Josef January 2014 (has links)
Purpose of this thesis is to check influence of turbulent model used for simulation of flow close to primary elementi inserted into piping. The goal is to check if results computed by these models are equal and how precise is their prediction.
90

Akustické mikroklima nevýrobních objektů / Acoustic microclimate non-manufacturing buildings

Jelínek, Ondřej January 2013 (has links)
This master´s thesis focuses on effect of acoustic microclimate in non-production buildings to human. Within elaboration this topic was made measurment acoustic power level and created protocols by valid technical standards and law. I dedicate to damping noise and aerodynamic noise in airconditioning in part topic analysis. The part aplication on real object deal with assessment current status and draft measure for improve acoustic ratio in laboratories in center of research located in Brno. That includes describe of air-cndition unit and development two variants and their rating.

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