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Wave Soldering Fluxes Comparison
Stoklásek, Lukáš ; Martinec, Petr (referee) ; Starý, Jiří (advisor)
Semestral thesis introduces the problematics of wave soldering fluxes, flux residues and problems of electromigration. Practical part describes measuring of ionic contamination by using conductometric method, measuring the wettability by the wetting balance method and amount of failures on wave soldered printed circuit boards with these fluxes. The main object is to compare quality of the fluxes.
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QFN Packages Soldering and Technology Procedures
Jakub, Miroslav ; Brno, Petr Martinec, HONEYWELL (referee) ; Starý, Jiří (advisor)
This master´s thesis deals with QFN packages soldering and technology procedures optimization. The aim of theoretical part is description of QFN packages, their assembly and reflow soldering on PCB in HONEYWELL. The aim of the practical part is to propose a method of measuring temperature and optimizing the thermal profiles of selected PCB with QFN packages by using convection (HONEYWELL) and infrared (BUT) reflow ovens. Comparison and evaluation of thermal profiles for 3 production PCBś with QFN packages using solder paste AIM NC257-2 were realised. The main part of master´s thesis are appearance evaluation of solder joints, preparing microsection and measuring intermetallic layers thickness by using the optical and the scanning electron microscopes, analysation and study of QFN defects created during soldering proces. These tests were performed with 2 production PCB´s. Optimization of SPI and soldering technology procedures where were analyzed QFN packages were processed on one type of PCB. Interesting part of this diplomma thesis is creating of the 3D heat transfer model of QFN package during the reflow soldering in SolidWorks.
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Preparation of Tobermorite
Dlabajová, Lucie ; Palou, Martin (referee) ; Martinec, Petr (referee) ; Ptáček, Petr (advisor)
This doctoral thesis is focused on the study of reactions in the CaO–SiO2–H2O complex system, primarily to the synthesis of crystalline tobermorite. Hydrothermal conditions are necessary for the formation of crystalline tobermorite, whereas the course of the reaction is influenced by several factors. The main studied factor was the choice of the silica sources differing in means of solubility, crystallinity, particle size distribution, specific surface area, and purity. The water-to-solid ratio turned to be also an important factor as the length of the hydrothermal reaction. The influence of the mechanochemical pretreatment of starting materials to the final phase composition of samples was studied as well. The obtained results show that the crystallinity of the silica source is the main factor influencing the reaction rate and the purity of the synthesized tobermorite. While using the crystalline silica source the shorter silicate chains are formed and the formation of tobermorite structure is easier. Using the amorphous silica sources and the mechanochemical pretreatement of starting materials prolong the hydrothermal reaction. The prepared samples are always the mixture of crystalline or semicrystalline calcium hydrosilicates instead of the phase pure tobermorite.
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Turbochargers for internal combustion engines.
Holík, Petr ; Martinec, Jiří (referee) ; Škorpík, Jiří (advisor)
This bachelor thesis deals with theme of turbochargers for internal combustion engines and shows basic systematic view of this theme. The work is divided into three main chapters. The first chapter deals with historical development and usage of turbochargers. The second chapter attends to working principle and energy transformation in the turbochargers. In the third chapter there are mentioned main types of turbochargers and their parameters and worldwide producers.
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The Use of Artificial Intelligence for Optimization of Production
Svoboda, Radovan ; Martinec, Petr (referee) ; Dostál, Petr (advisor)
This paper deals with the problem of optimization of a production plan by using genetic algorithms. It contains a brief overview of the principles behind genetic algorithms in scope of evolutionary algorithms and artificial intelligence in general. It also takes a closer look on the challenge of production planning and control and all activities connected to it. This is followed by description of the modification of genetic algorithms that needed to be done in order to implement it into a computer program, which is used to create and optimize the production plan, and is a result to the issue that this paper deals with. Incorporated is detailed escription of principles and functions of the program, that it offers to its users.
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Effectiveness Evaluation of Waste-to-energy process
Klimek, Petr ; Martinec, Jiří (referee) ; Pavlas, Martin (advisor)
This diploma thesis is focused on the evaluation of the effectiveness of using municipal waste to produce energy. On the basis of legislation applicable in the EU methodology is summarized evaluation of the facility as an energy recovery of waste. In the thesis is also created a consecution to determine decisive coefficients of legislatively-based criteria. The consecution is applied to the case study. Thesis serves as the basis for a software application.
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Stress analysis in parametric FEM programs
Martinec, Roman ; Vlach, Radek (referee) ; Krejčí, Petr (advisor)
The bachelor thesis focuses on familiarizing with Autodesk Inventor Professional 2012 program and ANSYS Workbench program. It was necessary to get familiarized with working environment of these programs and their mutual cooperation. The interconnection between the two programs is described on a demonstrative case. Next article of the thesis deals with a model conversion into MKP software which was described in detail within both programs. The final part of the thesis compares the results of a stress analysis within Autodesk Inventor Professional 2012 program and also within ANSYS Workbench.
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Experiments critical heat flux
Štaffa, Petr ; Martinec, Jiří (referee) ; Suk, Ladislav (advisor)
The Bachelor’s thesis deals with phenomenon of critical heat flux in a core of nuclear reactor. The first part is dedicated to describe physical nature of critical heat flux and basic thermo mechanical and hydrodynamics terms. The second part is dedicated to summarize experimental investigations on critical heat flux and their process.
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Intermediate heat exchanger natrium - natrium
Kupčík, Petr ; Martinec, Jiří (referee) ; Šen, Hugo (advisor)
This paper deals with intermediate heat exchangers in nuclear power plants. First section of this paper is devoted to analysis and divide of construction designs of intermediate heat exchangers in commercial and experimental power plants. There is a description of thermal, hydraulic and strength calculations during projection of IHX in the second chapter. There has been made a blueprint of loop type IHX in the final chapter of this paper.
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