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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.
301

Different approaches to determine the composition of the ultra-high energy cosmic rays in the Pierre Auger Observatory / Différentes approches de la détermination de la masse des rayons cosmiques d'ultra haute énergie faite à l'Observatoire Pierre Auger

Blanco Otano, Miguel 12 December 2014 (has links)
L’objectif de cette thèse est d’améliorer la détermination de la masse des rayons cosmiques d’ultra haute énergie faite à l’Observatoire Pierre Auger. Aujourd’hui cette mesure est faite à travers l’utilisation de télescopes à fluorescence qui nécessitent des conditions de luminosité spéciales réduisantle cycle utile à environ 10%. Trois approches différentes sont proposées:La première approche est une nouvelle analyse. Les muons issus des gerbes horizontales sont déviés par le champ magnétique terrestre. Cette déviation modifie l’empreinte au sol des gerbes atmosphériques et est fonction de la longueur de parcours des muons. Un estimateur de Xμmax, leur point de productionmaximum, qui dépend de la masse du primaire peut être construit.La deuxième approche explore la détection du rayonnement radio émis par les gerbes atmosphériques, une technique similaire à la fluorescence mais sans limitation du cycle utile. La détection du rayonnement de Bremsstrahlung moléculaire est revue et explorée de différentes manières.La troisième approche propose un nouveau type de détecteur pour le réseau de surface, ces détecteurs ayant une réponse distincte aux différentes composantes des gerbes atmosphériques : électromagnétique et muonique. La mesure de la composante muonique est aussi un moyen d’accéder à la nature du primaire.La nouvelle analyse semble un outil prometteur qui peut s’appliquer à tout lot de données. La radio-détection en revanche n’apparaît pas comme une alternative compétitive face aux techniques traditionnelles. Le nouveau détecteur offre de belles perspectives et devrait être considéré pour l'équipementdes futurs observatoires. / The motivation of this PhD thesis is to improve the capabilities to determine the mass composition of the ultra-high energy cosmic rays in the Pierre Auger Observatory. The measure of their mass composition is done with the fluorescence technique, that needs special luminosity conditions that reduce the exposure time to about 10% of the time. Three different approaches are proposed.The first approach is a new analysis. Muons in the horizontal showers are deviated by the magnetic field of the Earth. This deflection is related with different characteristics of the extensive air shower that allow the construction of an estimator to obtain an alternative measure of Xμmax, an observable sensitive to the mass of the primary.The second approach is to explore the detection of the radio emission produced in the extensive air showers, a technique similar to the fluorescente one, but without the limitations in the duty cycle. The detection of the Molecular Bremsstrahlung Radiation emission is revised and investigated from different points of view.The third approach is to propose a new surface detector that obtains different responses to the different components of the extensive air shower: electromagnetic and muonic. The access to the muonic component is another way to access to the composition of the primary particle.The new method of analysis proposed appears as a promising tool to be applied in any data set. The technique of the radio detection did not show clear indications of being an alternative to traditional techniques. The new detector represents a promising alternative to be considered in any future ultra-high energy cosmic rays experiment.
302

Ekonomika rychle rostoucích dřevin / Economy of fast-growing woody species

Levý, Lukáš January 2011 (has links)
The thesis is focused on analyzing and evaluation of importance and potential of fast-growing woody species for specifics of Czech economy and local conditions. Thesis will inquire into applicability of each fast-growing species for Czech natural conditions. Further I will investigate opportunities of subvention from public authorities. Next part of thesis will be focused on all activities and processes during cultivation of fast-growing species from acquiring land to processing of wooden mass. For each activity will quantify costs of labor and physical capital during cultivation of fast-growing woody species for different subjects in Czech economy, like household owning a soil or company with unused outside areas. Thesis will be comparing possible energetic savings of profits for a number of alternatives with different energy prices development in ongoing years. Practical output of this thesis should not be only the compilation of all these information into one text, but above all also a complex formula which everyone can use for the calculation of his opportunities for cultivating of fast-growing woody species.
303

Energetická závislost center světové ekonomiky / The world economic centers energy dependence

Bognárová, Eliška January 2011 (has links)
Today's world needs increasing amounts of energy for satisfaction of all human needs and wants. The fundamental problem is enormous disproportion among the areas with the largest energy consumption and places with the greatest energy reserves. This thesis set out to analyze the economic vulnerability of the biggest players in the world in terms of energy self-(in)sufficiency. The main focus of this thesis is to evaluate the status and future potential on the issue of fossil fuels, especially oil, natural gas and coal in the three world centers, the U.S., the EU and China. The thesis contains information about the alternative "clean" energy sources as well. Future energy development in these countries will affect their position in the world economy and mutual relations and also impact the current balance of power of these players.
304

Vliv tepelně izolační vlastnosti obálky budovy na její energetickou náročnost / Influence of thermal insulation properties of building envelope on its energy consumption

Eliáš, Filip January 2018 (has links)
This diploma thesis describes possibilities of thermal insulation of a detached house and choice optimization of insulating materials especially based on economic and ecologic factors. The thesis describes basic physical effects that are associated with heat transfer and that should be respected in insulation design. These effects influence the choice of suitable insulating materials based on their properties.
305

Napájecí zdroj Power-Over-Fiber / Power-Over-Fiber power supply

Kos, David January 2018 (has links)
This thesis deals with the possibilities of energy transmission by optical fiber for the purpose of powering of electronic systems. It comprises issues of electrical energy conversion to optical energy, coupling the power into the optical fiber, coupling between fiber and opto-electric transducer, conversion of optical energy to electrical energy, and transformation on required voltage levels. The principles of such Power-Over-Fiber are discussed in the first part of the work. Various technologies for the implementation of key system parts and their effectivity are discussed. In the next part, several Power-Over-Fiber commercial devices are compared. Subsequently, systems for Power-Over-Fiber experimental implementations are proposed. They are based on the utilization of semiconductor laser, multimode fiber, photovoltaic cell and related electronic circuits. The final part of the thesis deals with the construction of experimental systems and measurement of parameters of transmitted power and efficiency.
306

Úpravy čerpadla pro provoz v turbinovém režimu / Modification of pump for turbine regime

Jahn, Jan January 2019 (has links)
Hydraulic design of a hydrodynamic machine is designed to achieve a high value of energy transformation efficiency. Pumps and turbines have some different typical features in hydraulic design. With the aid of computational fluid dynamics, adjustments of the hydraulic parts of a standard centrifugal pump are assessed with the aim to increase hydraulic efficiency of the pump running as turbine. The impeller, volute casing and added draft tube are discussed.
307

Analýza nákladů rodinných domů / Household cost analysis

Havránková, Denisa January 2020 (has links)
The diploma thesis deals with the analysis of the cost of a house in the area of peripheral constructions and the effect of thermal insulation on energy consumption for heating and hot water. The theoretical part generally defines renewable energy sources, heat sources, thermal transmissions and structural losses, basics of valuation of construction works and supplies and overview of state subsidies. In the practical part are proposed composition of peripheral constructions, calculation of heat transfer coefficient of all designed perimeter structures and their subsequent evaluation. Furthermore, there is an estimated annual energy demand for heating and hot water and annual electricity consumption in the household. At the end of diploma thesis is a proposal of suitable energy sources and calculation of the return on investment in these sources.
308

Akumulace elektrické energie z obnovitelných zdrojů / Accumulation of electricity from renewable sources

Plíšek, Petr January 2021 (has links)
This diploma thesis deals with the issue of accumulation of electricity produced by renewable sources. The first part focuses on the description of possible ways of accumulation, especially with focus on those methods, that are suitable for renewable energy sources. The next part deals with the design of the accumulation energy in the compressed air for the selected photovoltaic power plant. The necessity of designing a particular method of energy storage, is also its technical and economic analysis, which is the content of the last part of the thesis.
309

Měřič kvality elektrické energie / Meter of powerline quality

Samek, Martin January 2011 (has links)
The subject of graduation thesis is a design of line analyser according to standard EN61000-4-30 class A. The analyser is determine to be used for quality control of supplied electric power which is, during electric power transmission, affected by several disturbances. Power line analyser should measure single-phase and three-phase network parameters in LV and HV systems. Measured parameters can be shown on the full colour TFT display, stored in the device memory or sent to other devices such as PC. For communication between the device and PC the USB, Ethernet or RS485 interface are used.
310

Elektrická vozidla jako akumulační prvek pro obnovitelné zdroje energie / Electric vehicles as energy storage element with renewable energy sources

Janečka, Jaromír January 2014 (has links)
This master thesis summarizes history of electric vehicles from its inception to present. Vehicles are divided into three groups according to the type of drive, special attention is paid to electric vehicles. Furthermore, typical ways of electric energy storage are presented, especially in the form of electrochemical cells, which are used in electric vehicles. The thesis also describes the situation of electromobility in the Czech Republic, namely government support, distribution companies tariffs, charging infrastructure and available electric vehicles. Finally, the concept of connecting electric vehicles to renewable energy source is described, with financial calculations for three profiled drivers.

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