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The nature of highly permeable flowpaths in the Turonian aquifers in the eastern part of the Bohemian Cretaceous Basin
Starý, Jiří ; Bruthans, Jiří (advisor) ; Datel, Josef (referee) ; Tesař, Miroslav (referee)
The thesis deals with the study of highly permeable porosity and the potential for karstification in the area of the East Bohemian Cretaceous synclines, which are of great importance for water supply. The susceptibility of the rocks to karstification was studied by taking cores and determination of their calcite content and by leaching the cores in 10 % HCl and monitoring of rock disintegration after leaching. A scanning electron microscopy and elemental mapping by microprobe were used to understand the structure and composition of the rock. The nature of the inflow zones to the boreholes was studied by evaluating available well logging data, particularly acoustic well logging, inflow data to the boreholes and by leaching rock samples from cores taken from the depth intervals where inflows occurred. A total of 247 cores taken from both boreholes and surface outcrops were studied. Only 5 % of the samples from the Turonian B, Ca, Cb aquifers that disintegrate from more than 50 % after leaching will form karst conduits in tectonically intact rock. This representation is much lower than in the Jizera Formation in the western part of the Bohemian Cretaceous Basin. Only a small fraction of the samples disintegrate if calcite content is below 78 %, the majority show no or very little disintegration. Only...
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Solderability of PCBs Surface Treatments and Environmental Influences
Jičínský, Jiří ; Zatloukal, Miroslav (referee) ; Starý, Jiří (advisor)
This bachelor’s thesis deals with the properties of surface treatment of printed circuit boards. The main purpose of this work is to compare the OSP coating applied under laboratory conditions and the technological procedure established in the company ČEMEBO Blansko. Samples of ENIG, immersion tin and OSP compare due to their critical aspects. In the practical part, the samples au exposed to various elements of nature according to ČSN EN 60068-2. The surface wetting balance method will be used for better comparison and evaluation.
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Temperature Profile in Reflow Soldering and Influence of Different PCBś and ComponentsThermal Capacities
Procházka, Martin ; Špinka, Jiří (referee) ; Starý, Jiří (advisor)
This thesis mainly deals with the prediction of temperature on the components and the PCB during reflow soldering. The theoretical part describes the particular solder reflow process, types of heat transfer and temperature profiles. The practical part is divided into forecasting temperatures if the conveyor is stopped and the temperature predictions when the conveyor is in motion. In both parts of the measured temperature is compared with the predicted temperatures, which show the success rate of prediction. The last part of this work is part of the simulation, which helps in proper understanding of the issues discussed.
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Analyse and Optimise Production Process of Prototypes
Hamr, Tomáš ; Zatloukal, Miroslav (referee) ; Starý, Jiří (advisor)
This diploma thesis summarizes basic findings about issues of making development samples of PCB. The emphasis is especially on required quality which complies with mentioned norms. The theoretical section includes methodology for evaluating quality dismounted boards, assembling and soldering, parameters of components under different environmental circumstances. The practical part is carried out in cooperation with the department EEG in R&D Automotive Lighting Jihlava. It is dedicated to the design and the preparation of development samples where the quality is assessed according to given methodology from the theoretical part. PCB are analyzed by an X-ray, metallographic grinding and other methods. Recommendations are given and based on results for improvements.
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Test Equipment for Solder Joint Strength Measuring
Čechák, Ondřej ; Špinka, Jiří (referee) ; Starý, Jiří (advisor)
This master thesis introduces the problematics of the tensile strength of soldered joints and the correlative mathematical formulas and the use of mentioned problematics in the technology of die shear/pull machines designed for the solder joint tensile strength measurement. It explains the importance and reasons for the use of this technology. The emphasis is then laid on the design and construction innovations of the current laboratory manual shear/pull measuring machine, its semi-automation and the possibility of utilizing the innovated system in a laboratory class of a subject on FEEC BUT.
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Wettability of PCB Surface Finishes and Comparison of Methods
Vídeňský, Ondřej ; Přikryl, Tomáš (referee) ; Starý, Jiří (advisor)
This bachelor´s thesis deals with testing methods for surface finishe´s wettability PCB. For this tests has been designed and created testing board which contains testing coupons for testing methods. Boards have been created and covered by surface finishes by Gatema Boskovice. In this thesis electroless nickel with immersion gold (ENIG) and immersion tin have been tested. For simulation of reflow soldering have been used test methods solder indicator, solder spread test and dewetting test. Wetting balance test method has been used as simulation of wave soldering.
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