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Practical verification of EMAT transducer parameters
Zlámal, Michal ; Havránek, Zdeněk (referee) ; Beneš, Petr (advisor)
The challenge is familiar with EMAT transducers, their basic characteristics and principles of operation. Inclusion of the theoretical knowledge acquired in Semester work 1 is based on the practical measurement of the frequency characteristics of transmitting and receiving part of laboratory made EMAT transducers. Based on the measured results should be followed by an improved design of sensor to achieve higher sensitivity with the appropriate shape of frequency response. For generating of exciting signal is expected to use LabVIEW programme environment. For credible results of the measurements in a broad range is needed to make broadband power amplifier for the transmitting and low-noise broadband amplifier for receiving part of EMAT transducer.
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Use of acoustic methods for assessing the influence of the composition of cement composites on the course of degradation caused by high temperature
Dvořák, Richard ; Medveď,, Igor (referee) ; Bílek,, Vlastimil (referee) ; Bodnárová, Lenka (referee) ; Chobola, Zdeněk (advisor)
The aim of this work is to optimize the acoustic nondestructive method (NDT) Impact-Echo (IE) as a complementary diagnostic tool for the assessment of concrete structures exposed to high temperatures. Commonly used diagnostic procedures for concrete structures affected by fire are most often limited to in-situ core drilling and subsequent testing of the drilled holes by destructive testing. The Impact-Echo method allows non-destructive testing of variously degraded test specimens and concrete structures, but its use for the assessment of temperature-degraded cementitious composites is hardly ever used in practice. Many studies suggest that Impact-Echo is one of the most suitable non-destructive methods for assessing the rate of degradation by elevated temperature. The dissertation work consists of three main stages, where the first stage is devoted to the production of test specimens of different mixtures and their subsequent degradation by elevated temperature and testing by the IE method and by reference destructive and non-destructive methods. The second stage consists of manufacturing a reinforced concrete element with built-in thermocouples and its subsequent inhomogeneous degradation by a local source of elevated temperature. The controlled degraded element thus prepared contains all grades of thermally degraded concrete tested in the first stage. Subsequent testing consists of verification of standard procedures in the field of acoustic NDT with simultaneous use of experimental modal analysis. In the third stage, the objective is to interpret the measured data from both previous parts, to verify whether within the closed element temperature-degraded areas can be distinguished from one another, or the degree of thermal degradation of concrete. Based on these results, the optimal testing procedure was determined and the basic assumptions for the creation of degrees of damage of the concrete by increased temperature were determined.
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Current Status of Nuclear Fuel Assemblies Inspections at Nuclear Power Plants World-Wide
Fendrychová, Michaela ; Temelín, Elektrárna (referee) ; Katovský, Karel (advisor)
This bachelor thesis deals with post irradiation examination (PIE) of spent nuclear fuel. The document briefly introduces basic light water reactor types (BWR, PWR, VVER) and construction of nuclear fuel for these reactors. Typical fuel failure types are described as well as methods for detection of such defects or failures. Consequently inspection methods suitable for commercial nuclear power plants are described. The primary goal of this thesis was to analyze existing inspection methods and to propose improvement of existing PIE at Temelín nuclear power plant. Therefore part of this thesis is devoted to description of fuel used at Temelín power plant, inspection methods currently applied at Temelín power plant and discussion of possible improvements of PIE.
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Modern trends in radiographic procedures and methods in defectoscopy
Skřivánková, Vendula ; Vlašic, František (referee) ; Juliš, Martin (advisor)
Presented thesis deals with modern trends and techniques in radiographic methods of crack detection which are recently used in engineering practice. In the first part, conventional (analogue) radiography principles based on creating a visible image of tested object to radiographic film are discussed. The next part is aimed to the digital radiography and radioscopy. To digitize existing X-ray film images, application of storage phosphor plates (CR), flat panels (DR) and computed tomography (CT).
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Modern methods in nondestructive testing of materials using ultrasound
Šimeček, Radek ; Stránský, Lubomír (referee) ; Juliš, Martin (advisor)
Theme of this bachelor thesis is nondestructive testing of materials by modern ultrasound methods. In the first part are mentioned defects of mechanical components, which can be detected by ultrasound. This is followed by a description of conventional ultrasound technique, including a list of the major disadvantages and limits. In the second part are analyzed the modern ultrasonic methods TOFD and Phased Array. It describes not only the principle of these techniques, but there are also provided practical examples of their application.
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Evaluation of Cyclic Damage in Aluminum and Magnesium Alloys Using Acoustic Emission Technique
Vlašic, František ; Samek,, Jiří (referee) ; Fiala, Jaroslav (referee) ; Pazdera, Luboš (referee) ; Mazal, Pavel (advisor)
The thesis deals with the application of nondestructive testing methods (acoustic emission, electron microscopy, X-ray diffraction topography) to description and identification of stages in the fatigue process in aluminium alloys. The main contribution of this dissertation thesis consists of the approach and evaluation methodology of cyclic damage in the materials. It dealt especially with the verification of measured data by using data obtained using other nondestructive methods. The experimental results show that the field of nondestructive testing materials can fundamentally uncover the process of fatigue damage and improve current knowledge in this area. Combination of used methods has become a powerful tool for the identification and monitoring of the whole fatigue degradation process of materials.
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Measurement of Acoustic Parameters of Building Materials by Pseudorandom Sequence
Carbol, Ladislav ; Semerák,, Petr (referee) ; Koktavý, Bohumil (referee) ; Vydra,, Vítězslav (referee) ; Martinek, Jan (advisor)
The thesis deals with research of pulse compression of the acoustic signal in terms of applications in civil engineering. Based on the study and analysis of these methods, automated measuring equipment for non-destructive testing with pseudorandom sequence of maximum length and automated signal analysis, have been designed and implemented. In a single test cycle are obtained three parameters that characterize the linear and nonlinear behavior of the sample. A nonlinear parameter, Time of Flight of ultrasonic wave in the sample is further in the work compared with the conventional pulse measuring, and spectral analysis is compared with the method impact-echo. Functionality and optimization of the testing method was performed on a total of three sets of test pieces made of various building materials. The experiments proved simple result interpretation, and high sensitivity to structural damage associated with temperature loading. The results were correlated with conventional nondestructive methods and by destructive testing was measured change in compressive strength and flexural strength. This work also includes continual measurement of fundamental frequency influenced by moisture on a mortar sample. Use of pulse compression signal is in the civil engineering quite unusual. Only in recent years this topic is discussed in scientific articles with increasing frequency. Great potential lies in the association of three test methods into a single. Beneficial is high test speed and measurement reproducibility, but also theoretical possibility of testing massive test elements.
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V5: Report on further collaboration with R6 Panel
Joch, Jaroslav ; Štefan, Jan
This report presents obligatory output V5 of project TAČR TK01030108: Innovative methods for nuclear plant safety evaluation based on SHM technologies and related procedures - NEMENUS (NEw MEthods for NUclear Safety). The report presents program of further collaboration with R6 Panel and other foreign partners established during the project.
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V7: Summary report NEMENUS for SÚJB
Štefan, Jan ; Joch, Jaroslav ; Převorovský, Zdeněk ; Gabriel, Dušan ; Krofta, Josef ; Chlada, Milan ; Kober, Jan ; Masák, Jan ; Kunz, J. ; Ashhab, B.
This is the final report of project TAČR TK01030108: Innovative methods for nuclear plant safety evaluation based on SHM technologies and related procedures - NEMENUS (NEw MEthods for NUclear Safety). In this report, the most important project results and outputs are presented, as well as a summary of its contributions with respect to long-term technological horizons.
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