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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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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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Influence of Inert Atmosphere on Surface Wetting in Lead Free Soldering
Nestrojil, Michal ; Špinka, Jiří (referee) ; Starý, Jiří (advisor)
This master´s thesis dealing with study of influence of inert atmosphere on the wettability of soldered surfaces. The theoretical part is discussed the issue of the soldering, solder joint, oxidation, and inert atmosphere. The glass cover with internal inert gas preheating for the wetting balance testing was prepared in the practical part. With this adjustment were realised tests, in which was examined the effect of the inert gases on the wettability of different materials combination. Further experiments were focused on plasma surface cleaning as possible flux substitution. The evaluation of these experiments were discussed in the end of this master´s thesis. Some of topics were designed for further experiments.
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Wetting Balance Method Modification for SMD Wettability Measuring
Drab, Tomáš ; Kahle, Petr (referee) ; Starý, Jiří (advisor)
Project presents main influence on wettability of SMD and PCB using solder SAC 305 and testing possibilities. We have designed modificaton of wettability balance method leading to the solder globule method. We were testing thermal profile difference and then we determined thermal difference compensation. We were testing few types of SMD packages terminations and PCB´s surface protections, with two solders and two fluxes. We were comparing their wetting forces, wetting speed, and wetting stability. We have proposed other possibilities to optimisation of the method and testing.
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Evaluation of wood surface treatments by non-destructive methods
Plšek, Matěj ; Brožovský, Jiří (referee) ; Vaněrek, Jan (advisor)
This bachelor thesis will be describing the basic technologies of timber processing and macroscopic signs according to which the visual strength grading is performed. Imaging methods will be described to identify the roughness of wood surface. In the experimental part, the surface roughness parameters for various surface treatment methods will be determined and the dependence of the surface roughness on wetting and penetration depth of the adhesive will be monitored.
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Behaviour of varnish composite in various environmental condtions
Kadlec, Michal ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
The diploma thesis is focused on the preparation of test samples of paint-filled micronized mica and analysis of electrical properties of insulating material values in different environmental conditions. For this purpose, it was created five sets of composite paint primers with different ratio of mica. Samples were gradually exposed to the environment relative humidity of 0%, 33%, 55%, 65% and 75%. For each environment with a defined moisture characteristics were observed in samples exposed to the temperature of 20 to 50 ° C. The diploma paper analyzed the influence of the mass implementation of mica in each set of samples and placed on the surface structure of samples.
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Evaluation of wood surface treatments by non-destructive methods
Plšek, Matěj ; Brožovský, Jiří (referee) ; Vaněrek, Jan (advisor)
This bachelor thesis will be describing the basic technologies of timber processing and macroscopic signs according to which the visual strength grading is performed. Imaging methods will be described to identify the roughness of wood surface. In the experimental part, the surface roughness parameters for various surface treatment methods will be determined and the dependence of the surface roughness on wetting and penetration depth of the adhesive will be monitored.
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Microbial activity of deep subsurphace miocen sediments near Soklov
Galertová, Renata ; Frouz, Jan (advisor) ; Kryštůfek, Václav (referee)
In my diploma thesis I observed microbial activity in Miocene sediments collected at two different depths - 30 and 150 meters - in the "Družba" open-mine pit, which is located in Sokolov Brown Coal Basin. There were three different types of sediment: lamellar, amorphous and transitional. Samples were obtained under sterile conditions and following treatments were applied to the transitional sediment: addition of glucose, wetting and freezing. The aim of my study was to observe the activity of the original microflora at various depths and the impact of environmental factors that can affect the quarried claystones after being put on heaps. Microbial activity was evaluated by measuring released CO2 (titration). Obtained values of microbial activity did not show any differences between the respiration of sediments of different ages (depths), but differences between different types of sediments were significant, the highest values were found in lamellar sediment. Affection of samples then showed biota activity response suggesting that microbial communities at lower depths are limited by nutrients. Because the application of glucose did not show any noteworthy effect, we can assume that these communities are specialize on present fossil organic matter they are able to decompose, which is important especially in...
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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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