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Design of an experiment to investigate the influence of mechanical vibrations and electric current during the soldering process
Nohel, David ; Jankovský, Jaroslav (referee) ; Otáhal, Alexandr (advisor)
This bachelor thesis focuses on the investigation of the effects of electrical current and mechanical vibrations on the process of forming a solder joint. The goal was to explore these effects together with the synergy of these two factors and their impact on the mechanical strength and microstructure of solder joints. An experiment was designed and conducted, involving the use of a mechanical vibration device and soldering apparatus with the capability of applying electrical current. The results demonstrated that mechanical vibrations can positively influence the strength of the solder joint, while electrical current significantly affects the structure of intermetallic layers. These findings could contribute to the further development of technologies and materials used in electronic soldering.
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Preparation and implementation of construction and technical survey of a building
Mezlík, Vojtěch ; Heřmánková, Věra (referee) ; Anton, Ondřej (advisor)
The subject of bachelor’s thesis is a structural-technical survey of a reinforced concrete frame structure. The theoretical part deals with the inspection of reinforced concrete structures, destructive and non-destructive diagnostic methods for the diagnosis of reinforced concrete structures, and the Czechoslovak architect Jaroslav Josef Polívka. The practical part conducts a structural-technical survey, focusing on the diagnosis of the reinforcement of selected structural elements and the determination of properties of the concrete. The reinforcement was determined using electromagnetic indicator Proceq Profometer 630 and the ground penetrating radar Hilti PS 1000 and verified by chiseled probes. The concrete strength class in the structure was estimated from core drills. In the conclusion, the condition of the structure is evaluated, and measures are proposed.
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Design of an experiment to investigate the influence of the frequency of mechanical vibrations on the structure of a solder joint
Podolák, Šimon ; Košelová, Zuzana (referee) ; Otáhal, Alexandr (advisor)
The main goal of this bachelor's thesis is to study the influence of vibrations on the structure of solder joints, specifically SAC305 solder paste droplets. The thesis consists of three parts: theoretical, practical, and evaluation of results. The theoretical part focuses primarily on solder joints and the phenomena surrounding them, such as diffusion, voids, crystal morphology, and others. It also describes vibrations and everything related to them, including ultrasound and its use in the field of soldering. The practical part deals with designing workstations for creating individual samples, specifically without vibrations, with 5 kHz vibrations, and with ultrasonic vibrations. This is followed by the process of preparing the samples and modifying them to a state suitable for microscopic examination. The final part involves evaluating the results obtained and comparing the samples with each other.
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Methods for instantaneous speed estimation in ultrasonic object detection
Šilar, Adam ; Pikula, Stanislav (referee) ; Havránek, Zdeněk (advisor)
The main goal of this master thesis is to explore suitable methods for estimating the instantaneous velocity of a moving object. The estimation of instantaneous velocity is based on the knowledge of the Doppler effect, which causes a shift in the frequency of ultrasound to another frequency depending on the velocity. Using the knowledge of the Doppler effect, a procedure is described for designing and programming a generator of simulated ultrasound data in the LabVIEW environment. The thesis theoretically describes methods for estimating instantaneous velocity, and selected methods are applied to test data to obtain information about the object's instantaneous velocity. The selected methods are tested for various parameters and compared with each other. The methods were subsequently practically tested on real measured data and compared with their simulated versions.
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New Areas of the Ultrasonic Application in Microelectronics Technology
Buršík, Martin ; Pietriková, Alena (referee) ; Králová,, Iva (referee) ; Szendiuch, Ivan (advisor)
Doctoral thesis deals with the deposition of special thixotropic materials for microelectronic technology. The aim of the work is the development of the new method optimizing the dosing process in order to achieve a print resolution of better than 100 microns. The work includes the development of a special dispensing head (UZD) using the influence of ultrasonic energy. These results demonstrate the possibility of a newly developed method that is able to print thixotropic materials with a resolution of 65 microns. Compared to other methods achieves these results with the commonly used materials for thick film technology with particle size up to 5 microns.
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Feature extraction from image data
Uher, Václav ; Beneš, Radek (referee) ; Burget, Radim (advisor)
Image processing is one area of signal analysis. This thesis is involved in feature extraction from image data and its implementation using Java programming language. The main contribution of this thesis lies in develop features extractors and their implementation in the program RapidMiner. The result is a robust tool for image analysis. The functionality of each operator is tested on mammogram images. A function model was developed for the removal of artifacts from the mammography images. The success rate of removal is comparable with other similar works. Furthermore, learning algorithms were compared on example detection of ventricle in ultrasound image.
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Measurement and evaluation of flows in sewer networks
Haška, Aleš ; Prax,, Petr (referee) ; Raclavský, Jaroslav (advisor)
Measuring flow rate, water surface and rainfall are the crucial inputs for the calibration of the hydraulic model. This bachelor’s thesis presents mathematical models and measuring devices for the sewer networks. This thesis summarises the measuring devices that are currently available and used on the sewer network. Furthermore, theory of random and systematic errors is discussed. In the second section, this theory is implemented in the chosen area for the sewer network in Znojmo. On the 9. 9. 2020, three ultrasonic measuring devices (type ISCO 2150 with AV sensor) and one device for measuring water surface (type IJINUS) were installed in this area. This thesis provides continuous measurements which are then applied for the calibration of the hydraulic model. On completion of this thesis it is necessary to continue to calibrate and verify the model in order to increase accuracy and be more precise.
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Ultrasonic eraser of tartar
Novotný, Jan ; Dlouhý, Jiří (referee) ; Rozman, Jiří (advisor)
The aim of this thesis is to provide insight into certain elementary methods of removing tooth stone. Also, the thesis aims to introduce different techniques of removing tooth stone. The first part of the work analyses the theory of rise tooth stone, his create and biologically effect. Further, the elementary methods of removing tooth stone by ultrasound are introduced. In the second part, the thesis analyses the concept of instrument to removing tooth stone by ultrasound. The aim of this thesis is for working frequency 27 kHz propose circuit diagram of exciter generator. For intensity ultrasound 6W/cm2 count parameters sandwich converter and waveguide.
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