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Flux Residues after Reflow Soldering
Uhlář, Vít ; Špinka, Jiří (referee) ; Starý, Jiří (advisor)
The aim of this bachelor thesis is to solve flux residue characteristics on PCBś after reflow soldering and compare different solder pastes. The first part deals with the issue of solder paste application and flux residues. The second part focuses on the process of reflow soldering. The third part is devoted to the measurement methodology of flux residues. Finally, project is a practical part, which is summarized in the production of test samples and contains measurement results.
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Photo-Contest on Facebook
Pololáník, Petr ; Kolář, Martin (referee) ; Beran, Vítězslav (advisor)
This bachelor's thesis deals with the theory of creating modern web applications, whose logic is solved predominantly on server. Various technologies that are commonly used are analyzed. Thesis mainly deals with creating specific application for managing photo-contests on Facebook site. These photo-contests are organized by companies to expose their brand. Requirements for the application are specified and a final draft is created. Then the implementation and application scalability are described.
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Hot dip galvanizing of the steel construction
Pometlo, Stanislav ; Vyplašil, Evžen (referee) ; Kubíček, Jaroslav (advisor)
This master´s thesis deals with hot dip galvanizing of steel constructions and their protection from corrosion. This work describes the origin of corrosion of steel and its corrosion in different areas and presents degreasing and pickling before hot dip galvanization. It describes possibilities of making zinc layer by the wet and draw method of hot dip galvanization. Furthermore, it puts forward reactions between zinc and iron, possible defects of the zinc layer and influence of the hot dip galvanizing on the steel constructions. The experimental part examines the influence of the hydrogen charging on the material and the time of the flux operation on the quality of layer. The work further analyses the changing of mechanical properties of steels Hardox 500 and Weldox 700 as a result of the hydrogen embrittlement during pickling by the hydrochloric acid.
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Optimization of Gases Flow in Exhaust System of Tractor Engine
Létal, Filip ; Svída, David (referee) ; Dundálek, Radim (advisor)
The subject of this thesis is to optimize the flow of exhaust gases in the particle filter using CFD simulations. The first part is focused on the emissions of diesel engines and emissions reduction systems with a focus on particulate filters. The next section is an analysis of the current state of the specified particle filter using CFD simulation and evaluation following with a proposal of new construction for better flow distribution. At last, the final evaluation is presented.
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Solder Wave Process Optimization
Procházka, Martin ; Brno, Martin Štěpánek HONEYWELL (referee) ; Starý, Jiří (advisor)
This work describes solder wave process and it‘s optimalization. It informs us about wave soldering and describes it’s fragments. Next it is described partition of fluxes and their properties. In practical part is described researching of defects on PCB’s and analysis of possible reason of defects, measurement of the weight of sprayed flux and measurement of solderable profile.
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Design systems used in the field of electrical apparatuses
Stejskal, Jiří ; Krejčí, Jan (referee) ; Valenta, Jiří (advisor)
Bachelor´s thesis is engaged on the base of submitter´s requests company OEZ, s.r.o. and is divided into two parts. The first part of work deals with the most often used 2D CAD systems that are used by designers according to their answers in the area of suggestion of electric switchboards low voltage. In the work are described main possibilities of these systems, then what kinds of data format are supported by them. In the second part of the work are described programs established on calculation of warming switchboards. It goes about programs, which supply concrete producer of switchboard case, and further programs based on method of final elements and method of final volume, which enable graphic representation of results.
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Solder Joint Reliability and Wetting Characteristics Influence
Labaj, Radek ; Stejskal, Petr (referee) ; Starý, Jiří (advisor)
This thesis deals with the methodology of testing the wetting characteristics for different material and process effects in the double-plated base material. Testing is performed by wetting balance method. There is designed procedure to calculate the angles on each side of the non-homogeneous material. The Design of Experiments method is used to interpret the results, by using this method are also interpreted electrical and mechanical properties of solder joints. The correlation with wetting characteristics is discussed.
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Effects Affecting BGA Soldering
Janíček, M.
This paper deals with effects, which can affect solder joints quality. It also evaluates experiments which were made. These experiments were connected with fluxes problematic. First there are mentioned effects connected with amount of flux, and then experiments were focused to ways of applying the flux. Next steps are mentioned at the end of the paper.
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Phosphorus release from sediments - a comparison of methods
Borovec, Jakub ; Brzáková, Martina
Phosphorus release rates from sediments were compared at two localities of Jordan Reservoir (Czech Republic) during the year. The release rates measured by incubation method were an order of magnitude higher comparing to the release rates calculated from phosphorus gradient in pore-water. A rapid decomposition of freshly settled seston at the sediment surface or just above the sediment was suggested to explain the differences.
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