National Repository of Grey Literature 98 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Dielectric Elastomers
Fiala, Vojtěch ; Špinka, Jiří (referee) ; Starý, Jiří (advisor)
The thesis contains extensive theoretical information and consist of several parts, where in the first part of the text are specified mainly general knowledges about electroactive polymers (EAP) and their different types. In this part, the reader should get a basic view of the issues and realize sense of these materials. The following text is more specifically addressed on one group of electrical EAPs called dielectric elastomers (DE). Introduction to DE is conceived comprehensively, that means from general information and principles of function to specific and deeper information. For example in the text are included information about individual materials and differences between them, particular application areas, etc. Above all, the text focuses on the fields of sensorics and energy generation.
Manual Soldering Station - Evaluation of Selected Parameters
Němec, Ivo ; Špinka, Jiří (referee) ; Starý, Jiří (advisor)
This semestral work deals with the investigation of different principles of heating elements control in soldering stations and the influence of lead-free solder alloy on the life of soldering tips. The thesis summarizes the description of the sub-elements of the soldering stations and explains their functions. The defects of the soldering tips due to the use of lead-free solder alloys are also described. Last but not least, European directives governing the use of lead-free solder alloys in electronic and electrical products are mentioned.
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.
SnBi Solder Paste and Influence of Reactive Nanoparticles
Rychlý, Ivo ; Špinka, Jiří (referee) ; Starý, Jiří (advisor)
This work deals with effects of nanoparticles, mainly copper and silver, on properities of lead-free solder pastes. It describes basic tests done on solder pastes according to IPC-TM-650 standards. In practical section this work focuses on the preparation of Sn-Bi solder paste and the measuring of viscosity. After that different concentrations of silver copper alloy nanoparticles are added to the SnBi solder paste. These solder pastes are tested by the IPC standarts and mechanical and resistive tests are done on printed circuit boards where the effects of mixed in nanoparticles are observed.
Reactive Nanoparticles Application to SAC 305 Solder Paste
Matras, Jan ; Špinka, Jiří (referee) ; Starý, Jiří (advisor)
This work is a research on the topic of reactive nanoparticles and their agitation into the solder paste, which it also describes. It describes in detail the properties of each solder alloys. It explains the creation of intermetallic layers in the soldering process and examines their structure. It also focuses on the evaluation and methodology of testing the properties of solder pastes. In the practical part, individual tests are performed with PF606 and PF610 solder paste.
Wetting and Spreading of Solder on PCB Surface
Wiesner, Lukáš ; Špinka, Jiří (referee) ; Starý, Jiří (advisor)
This work deals with the metal surface wetting problems of molten lead-free solder and monitoring of ongoing processes at the inter-phase interface. This work also deals with flushing monitoring of spreading velocity on solder finishes Ni/Au and Immersion Sn deposited on copper plated base material FR4 using digital cameras. Measurement is performed at the improved workplace. After the reflow process is measured by length of spreading solder. It evaluates and compares the time dependence of velocity of spreading solder for Ni/Au and Immersion Sn finishes.
Mapinng and improving logistic flow in the firm ZEBR.
Kmeť, Lenka ; Vyroubal, Petr (referee) ; Špinka, Jiří (advisor)
The aim of the project is to chart the course of logistics and information flows of the selected company, to eveluate the entire process and to find improvements. In the first part there is mentioned an introduction into methods of lean manufacturing, value stream mapping and throughput time calculations. In the next section the flow of values is mapped and the map of current state is created. Futhermore, the throughput time of selected parts is computed and the mounting diagram of measured products is assembled. On to these materials are founded the sources of wasting and solutions are suggested. Afterwards on the basis of the obtained data are given solutions eveulated in terms of economic indicators.
Solder Joint Quality based on Heating Factor
Kučírek, Martin ; Špinka, Jiří (referee) ; Starý, Jiří (advisor)
Master’s thesis in the theoretical part analyses the heating factor (Q), which has significant share on quality of a solder joint. The practical part describes the design and production of test PCB and setting temperature profiles, SMD resistors soldering by using BiSn solder paste. Shear tests of SMD solder joints were realised and evaluated including isothermal ageing samples. At the end of master’s thesis solder joints visual aspects and defects were evaluated, measurement thickness of intermetallic compound by not only optical microscope but also SEM, discussion about results and Q was evaluated.
Reliability of LED Panels Solder Joints
Šimon, Vojtěch ; Špinka, Jiří (referee) ; Starý, Jiří (advisor)
Thesis is focused on the effect of heating factor on quality of solder joints. In theoretical part is solved reflow soldering technology, problematice of solder paste choice or criteria of soldering profile setting. The practical part is dedicated to demonstrating the impact of heating factor on solder joint quality. There are used X-Ray analysis, microsections and electron microscopy. In the final part of this thesis are summarized knowledge from theoretical part and experimental obtained results to defend of next steps in diploma thesis.
Diagnosis of high voltage capacitors for cascade voltage multiplier
Baev, Dmitriy ; Špinka, Jiří (referee) ; Krbal, Michal (advisor)
The main subject of the final thesis is to find a suitable method for measuring the partial discharge (PD) in the dielectric of high-voltage capacitor. In the theoretical part of my thesis contains from the mechanisms of origin and the harmful effects of partial discharge at high voltage insulation of capacitor. It describes the global galvanic method of partial discharge measurement, the principle of cascade voltage multiplier, its main components are high-voltage capacitor and diode, facilities quality measurement of capacitors for voltage multipliers, advantages and disadvantages and principles of HIPOTRONICS DDX-8003 with the pulse discrimination system. In the experimental part of the diploma thesis is familiar with the diagnostics of high – voltage capacitors by means of laboratory measurements on the electronic bridge and with the help of partial discharge measurement system. Design of suitable electrode arrangement is described which eliminates the influence of corona which makes it impossible to measure partial discharges and the dissipation factor (tg ). Analysis data from measurement and determination of quality level, eventual degradation of measured capacitors. The result of this project should be designed the methodology for finding of poor – quality capacitors in order to increase the reliability of the voltage multiplier.

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