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Solder Joint Reliability Prediction
Stejskal, Petr ; Skočil, Vlastimil (referee) ; Hovorka, Ladislav (referee) ; Kazelle, Jiří (advisor)
The thesis deals issue of the solder joint reliability and diagnostics. The manufacturing technology of electronics currently features a very high level of perfection. A large number of electrical devices ends its functional life due to solder joint failure. The objective of presented research consists studies of processes taking place in the solder joint due to soldering and after soldering. To this end, I will employ several methods of diagnostics. Noise based methods of solder joint measurement was evaluated. Based on a detailed study and understanding of processes it can be solder joint reliability predicted.
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Application possibilities of refractometer for liquids diagnostics
Macháč, Milan ; Kazelle, Jiří (referee) ; Frk, Martin (advisor)
This bachelor thesis focuses on application possibilities of refractometer for liquids diagnostics. The first part of the thesis focuses on the theoretical basics propagation of electromagnetic waves. The next section focuses on the measurement of refractive index, refractometry, a description of each type refractometers and short introduction to interferometry. The penultimate chapter is devoted to an application using a refractometer and what can measure and calculate. The last chapter is a practical part, there is described a calibration process, the measured values of the refractive index of liquids and evaluate the results.
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Piezoelectricity in technical practice
Škarabelová, Lenka ; Frk, Martin (referee) ; Kazelle, Jiří (advisor)
Bachelor's thesis is dedicated to the study of the principle and possibilities of use of the piezoelectric effect. Since the use of piezoelectric effect in electrical engineering is very extensive, the main focus is placed on the ability to exploit this effect in the field of ultrasonic and piezoelectric resonators. Next aim of this work is practically and theoretically to get acquainted with the measurement of small changes in weight, using electrochemical quartz crystal microbalance (EQCM), also with an ultrasonic equipment from company Olympus and ultrasonic defectoscopy for detection of possible imperfections in the material and their evaluation.
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Study of Metal Oxides and Hydroxides in Aqueous Solutions
Špičák, Petr ; Trnková, Libuše (referee) ; Kadlec, Jaromír (referee) ; Kazelle, Jiří (advisor)
This dissertation work deals with analysis of nickel hydroxide phases, their oxidation compounds, their stability and degradation mechanisms of electrochemically more active alpha phase on standard beta phase. The active material was prepared by both methods, electrodeposition and chemical precipitation. Main analysis method was Electrochemical Quartz Crystal Microbalance in combination with common analytical methods (cyclic voltammetry, potenciometry) can resolute between alpha and beta phases and quantitatively describe differences in main reaction by monitoring mass changes in the active material. Poor stability of the ?-Ni(OH)2 were improved by adding cations with valence two three and four into the structure instead of Ni atoms. The most important role plays cobalt and its hydroxide. Totally new way is to use titanium in combination with other cations. In electrolyte the most significant addition is LiOH, which has beneficial influent on cycle ability, stability in strong alkaline medium and cycle life.
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High temperature conductivity measurements of ceramic materials
Grochal, Peter ; Kazelle, Jiří (referee) ; Novák, Vítězslav (advisor)
The aim of this work is to get acquainted with the detailed structure of yttrium-stabilized zirconia, focusing mainly on conductivity. Coating platinum electrodes by screen printing. Solution of complexity of conductivity segregation by electrode geometry. Measurement of the conductivity of macroscopic samples of ceramics by impedance spectroscopy to determine the electrical behavior of the system. Creating equivalent circuits to measured data. Detect system behavior when excited by different AC voltage and electrode geometry values.
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Additives effect on electrical properties of the epoxy resins
Šebesta, Petr ; Kazelle, Jiří (referee) ; Frk, Martin (advisor)
Work was carried out in collaboration with SYNPO, Inc. Pardubice, which provided samples resins with various additives for measurement. The work is divided into three theoretical and one practical chapters. The first chapter focuses on dielectrics in general. It deals with their properties and storyline running in them. The second chapter discusses epoxy resins, their formulation, production and application in manufacturing. The third chapter offers a view of the measurement methods used for diagnosing electrical dielectrics. The practical part describes the preparation of samples and their composition, and consequently their measurement with the evaluation of measurement data.
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Ultrasound in material diagnostics
Kristek, Michal ; Frk, Martin (referee) ; Kazelle, Jiří (advisor)
Objectives of the semestral project are to study the physical basis of ultra acoustic and comprehend the basics of ultrasound usage in diagnostic of materials. I should also become familiar with functions and usage of ultrasound device EPOCH LT made by OLYMPUS and perform measurement of thickness and speed of ultrasound spreading in selected materials.
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Dielectric properties of epoxy resins
Matoušová, Klára ; Novák, Vítězslav (referee) ; Kazelle, Jiří (advisor)
This diploma thesis deals with the fundamental properties of epoxide mixtures, as determining of these fundamental properties of epoxide mixtures could in the case of favorable results lead to diminishing the amount of defects in epoxide-embedded instrument transformers. As the influence of effects in the manufacturing process of transformers causing poor quality is very extensit, the biggest emphasis is laid capitally on the influence of the epoxide casting mixture composition. The thesis describes the manufacture technology including used methodics and materials. The compositions of epoxide resins and the mechanisms of their curing. Also, the definitions of fundamental properties of dielectric materials and the description of diagnostic methods used to relative permitivity, dissipation factor and inner resistivity are included. suitable casts of acquired samples were set and dried out within the experimental part, followed by measurement of fundamental electrical properties in temperature and frequency relations. Hereafter a comparison of individual samples and the evaluation of their electrical properties will be carried out.
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High temperature conductivity measurements of ceramic materials
Grochal, Peter ; Kazelle, Jiří (referee) ; Novák, Vítězslav (advisor)
The aim of this work is to get acquainted with the detailed structure of yttrium-stabilized zirconia, focusing mainly on conductivity. Coating platinum electrodes by screen printing. Solution of complexity of conductivity segregation by electrode geometry. Measurement of the conductivity of macroscopic samples of ceramics by impedance spectroscopy to determine the electrical behavior of the system. Creating equivalent circuits to measured data. Detect system behavior when excited by different AC voltage and electrode geometry values.
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