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Manufacture of castings from electrical copper
Janský, Vojtěch ; Lána, Ivo (referee) ; Záděra, Antonín (advisor)
The goal of this thesis is to verify influence of conditions of metallurgical treatment, used foundry technology and conditions of solidification on electrical conductivity of pure copper castings. The experiment part observe differenec between alloy melting under normal pressure and in a vacuum and betwwen casting provided with chill, insulation and natural enviroment of mould.
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Properties of aprotic electrolytes for lithium-ion accumulators
Staněk, Vladimír ; Máca, Josef (referee) ; Frk, Martin (advisor)
The present work deals with the properties of suitable electrolytes for lithium-ion batteries. The first part described in the current issue of electrolytes for lithium-ion batteries, types of solvents and their properties and methods of measurement properties. The second part is devoted to the measurement of the properties of solvents and electrolytes such as relative permittivity, density and viscosity. Measurement of relative permittivity was focused on the measurement of the solvent mixture with varying the percentage of the solvent. Viscosity and density were measured on a solvent with a lithium salt added (final electrolyte).
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Dielectric properties of liquid insulators
Jahn, Michal ; Starý, Jiří (referee) ; Špinka, Jiří (advisor)
This master‘s thesis deals with measurement of liquid dielectric materials (insulators). Above all, it is the different kinds of clean and drinking water, but also transformer oils. There was done theoretical information retrieval about the given topic in this project and on the basis of theory there were realized the relevant measurements of selected properties of liquid dielectric, such as permittivity, capacitance, loss number, conductivity, but also temperature dependence of these parameters. The measurements were realized with the help of product manufactured at the faculty FEKT VUT and with the help of measuring system AGILENT 16452A. The measured results were evaluated, graphically processed and compared.
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Effects of soil management on soil quality near Šardičky village
Schneiderová, Šárka ; Doležal, Petr (referee) ; Kameníčková, Ivana (advisor)
This diploma thesis is focused on influence of reduced tillage technology of soil processing on it´s near-surface soil layer (0 to 10 cm). The research was carried out on agricultural land near Šardičky village, where company ZEMO spol. s r.o. provides long-term use of reduced tillage technology. In 2016 the soil quality in this site was evaluated by using physical and hydrophysical parameters, results are presented in the previous bachelor thesis "Selected hydrophysical parameters as indicators of soil quality.". In diploma thesis in addition chemical and other hydrophysical properties have been evaluated to provide a comprehensive assessment of soil quality. In 2016, poppy seed was grown on this site and spring barley was grown in 2017 and 2018. Grab samples and intact soil cores were taken during the vegetation period of the crop. After three years of experimental research, in which I participated, it is possible to assess the development of individual parameters and the influence of reduced tillage technology on near-surface soil layer. The theoretical part of the diploma thesis deals with the description of the reduced tillage technology and problematics of the determination of soil parameters, which are used for evaluation of the quality of the near-surface layer. The practical part deals with evaluation of these parameters according to various authors and describes the development of soil quality during years 2016, 2017 and 2018.
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Mechanical and Electrical Properties of Thin Metal Films Deposited by Vacuum Evaporation
W. F. Yahya, Doaa ; Kolařík, Vladimír (referee) ; Štencl,, Jiří (referee) ; Šandera, Josef (advisor)
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.
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Solder Joint Conductivity - Influence of Solder Volume and Isothermal Aging
Mach, Ladislav ; Schnederle, Petr (referee) ; Starý, Jiří (advisor)
The master thesis analyses electrical conductivity of lead-free solder joints. The test method design for monitoring the electrical conductivity of the soldered joint is described in the practical part. Simulated BGA package with four pin (BGA4) is used for experiments. Tested PCBs are subjected to isothermal aging and current load. During isothermal aging is measured electrical conductivity and optical microscope is used for intermetallic layer (IMC) growth observation. Two types of surface finish (OSP and ENIG) are used for tests and three diameters of solder terminal balls (solder alloy SAC405). The influence of the ratio area connection / solder volume (ratio S / V) on lead-free solder joints conductivity was evaluated.
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Methodology of Determination of Electroinsulating Properties
Čanigová, Veronika ; Nevřivová, Lenka (referee) ; Sokolář, Radomír (advisor)
The core of this bachelor thesis is porcelain and electrical porcelain property specification accompanied by definition and explanation of electric conductivity. The theoretical section provides insight into electrical porcelain production from initial raw material exploitation to final stages of body baking. The experimental part compiles a number of electrical porcelain test methods based on current European standards and draft test procedures, which are followed in order to specify properties of conventional electrical porcelain as well as emerging anorthite porcelain based on aluminate cement.
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Electrical conduction of alternative electroinsulating liquids
Reňák, Ladislav ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This labor deals with features of alternative electrical insulating liquids and also petroleum-base liquids. It examines their usage in the electrotechnical industry. The practical part of the thesis deals with measurement of absorption charakteristics of biodegradable electrical insulating liquid MIDEL 7131 and the petroleum - based transformer oil TRAFO N. The results of the measurement are examined by the help of substitutional math function.
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Mechanical properties of gel polymer electrolytes
Bárta, Vladimír ; Vondrák, Jiří (referee) ; Sedlaříková, Marie (advisor)
This work deals with the measurement of electrical conductivity and mechanical properties of gel polymer electrolyte containing Lithium ion. Their preparation and performance depends on the concentration of nanoparticles Al2O3 contained therein. The theoretical part deals with the development of gel polymer electrolyte, their use and methods of measurement of electrical conductivity and mechanical properties. In the experimental part describes the preparation of gel electrolyte, the measurement of electrical conductivity, temperature dependence and the measurement of mechanical properties.
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