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Vibration diagnostics of bearings
Navrátil, Pavel ; Mazal, Pavel (referee) ; Klapka, Milan (advisor)
This bachelor’s thesis introduces the basic principles of vibrodiagnostic methods and their importance for individual fase of bearing’s damage. The selected methods studied are: acoustic emission, SPM (shock pulse method), SEE (spectral emission energy), envelope method, High frequency emission, Crest factor, Kurtosis factor and special method for slow-motion machines Adash Compressed Time.
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Anti-noise Protective Agents in Tractors
Hudec, Miroslav ; Svída, David (referee) ; Dundálek, Radim (advisor)
The aim of my bachelor´s thesis is anti-noise protective agents in tractors. In this work I focused on influence of wanted and unwanted noise to humans and the results of it. In other part I concerned with simple calculation of noise, each sources´ vibration and sound transmission of solids. These calculations are very complicated and complex but for my purpose I simplified them and used only the basic ones. The next procedure is to clear out the noise by constructional alterations, which are much-used. At the end I mentioned the used materials and where they are used for clearing out the noise. In the conclusion Ispecified some tractors´ marks and their used constructions and materials in a different parts of a tractor.
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Redesign of Vibration Power Generator with Respect to Overall Volume and Weight
Vaněček, Michal ; Dušek, Daniel (referee) ; Hadaš, Zdeněk (advisor)
This work deals with improvement construction already of the vibration power generator design. The improvement his feature and search ideal construction with reference to material, proportions and power. Gain here mechanical properties, to come to what best tune up and development of new construction for improved check out characteristics as is achievement. Tuning up of correct parameters proceed by the simulation and modelling in ANSYS and MATLAB environment.
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Vibration damper development and innovation of a laboratory stand
Filipi, Jaroslav ; Mazůrek, Ivan (referee) ; Nevrlý, Josef (advisor)
Bachelor work deals with description and functionality of vibration dampers. Since the vibration dampers is a wealth of species, work is focusing on the dampers used in cars known as shock absorbers suspension. I have described conventional shock absorbers suspension and modern shock absorbers suspension. Furthermore, I described active chassis. High-quality equipment is very important for the future development of dampers. I propose possible ways of innovation existing laboratory stand.
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Analysis of dynamic effects acting on crossings
Vukušičová, Daniela ; Vukušič, Ivan (referee) ; Smutný, Jaroslav (advisor)
This thesis is focused on measurement and analysis of dynamic effects on railway turnouts. Two turnouts with different wear condition were chosen. My attention was focused mainly on the crossing part of the turnout, where the highest dynamic impacts occur. The point of the thesis is comparison of the crossing part of turnouts in term of dynamic behaviour and assessment of influence of the wearing depth on dynamic effects. A part of the thesis is proposal of methodology of the measurement and convenient mathematical apparatus for analysing of dynamic effects on crossings.
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MEASUREMENT OF DYNAMIC PARAMETERS OF TRACK GRID
Podolník, Adam ; Tomandl, Vladimír (referee) ; Smutný, Jaroslav (advisor)
Coupled with theory analyses, various static and dynamic tests carrying out in laboratory or directly on site serve as a basis for selection and comparison of particular rail superstructure parts. It should be noted that the theoretical analysis of the application of mathematical modeling is often based on highly idealized assumptions. The purpose of this bachelor thesis is the experimental analysis of dynamic effects of selected flexible fastening structures without baseplates. Forces induced by the passage of trains have been simulated on a specially prepared samples using inertial exciter. Additional measurements of the dynamic response of structures to shock induced by a modal hammer were also performed. Measurements were performed in the laboratory of ÚPKO and ÚŽKS and in situ.
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Použití speciálních kotoučů u rozmítacích pil
Železný, Antonín
Circular saw blades are the most common woodworking tools in wood practice. This thesis describes the mechanical instability of saw blades and consequently their noise. When modificating saw blades it is possible to avoid partially these problems and achieve the maximum cutting quality and productivity. The thesis also examines the impact of the noise on human body and proposes measures designed to reduce noise of the saw blades. In the experimental part of the study we are solving the impact of the speed, the type of gearing, feed speed and type of wood swept noise level and frequency of the disc wheels oscillation.
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Hygiene Factors Issues of Noise, Dust and Vibrations in the Workplace Grinding Castings
STODOLOVSKÁ, Květa
My diploma work is focusing on the health problems of selected factors in the working enviroment of grinding the metal castings. There are high-risk factors, which are harmful to worker´s health, especially physical stress, noise, dust and vibrations, which are passed on hands. The employer is under the obligation to take precautions to carry on worker´s health, in consideration of exceed the health limits. The aim of this diploma work was setting the efficiency of precautions to health protection in work enviroment. The situation had been monitoring in a company in the South Bohemia over ten years. There were used results of factor´s precautions (noise, dust, vibrations) in work enviroment, where workers grind the metal castings by hand grinders. The monitoring ensemble was created by employess in a company, which makes the metal castings by hand grinders in its work enviroment. To data collecting were used the following methods: non-aligned observation, conversation with the chief of the company, studying of positive law and technical literature incl. test codes of the health institute (department Ceske Budejovice). The data of the test codes were processed by the secundary analysis and summarized to tables and graphs. Within qualitative analysis I determinated four research questions, which were answered gradually in my work: 1)Which precautions are carry out by employers to particular factors of employee´s health protection? 2)What is the factor´ s efficiency? 3)What impact do the precautions have on results of factor´s measuring? 4)Which precautions can I recommend on the grounds of the evalutation of the work enviroment? Both means of collective and individual protection belong to the precautions of worker´s health protection today. The technical, technologiacal and organisational precautions are included to collective protections. The individual precautions are focusing especially on employees and offer the substitute solutions. All precautions are specific to individual factors. I found out, that all precautions, which are used by the employers in work enviroment of metal casting, are effective. Especially we can talk about the precautions to protection of employee´s health against excessive dust (instalation of air ventilation with strong effect), which caused the exceed of dust concetration in work enviroment of grinding. Finally I can say, that this branch of metal casting has been connecting with certain high-risk factors all the time. Although all the protective precautions has been realized, the health limits given for noise, vibrations passed on hands and dust are still exceed. For this reason it´s very important to regularly inform the workers of high-risk factors, which they could meet in their work enviroment of cast grinding.
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The Health Risks Analysis in the Workplace of Stone Quarries, Measure and Evaluation
STODOLOVSKÁ, Květa
The purpose of this thesis was to evaluate the work environment of quarries. Four research questions were asked: What factors can be determined in the working environment of quarries? Are hygienic limits of the monitored factors in the work environment of quarries respected? What measures to protect the health of workers in the quarries are applied by the employers? Are the proposed measures to protect employees' health effective? The bachelor thesis was conducted as qualitative research. Conditions in two quarries in the South Bohemian Region were studied. For data collection, the technique of direct, disinterested and obvious observation, the study of professional literature, legislation, trial protocols and the findings obtained from interviews with managers were used. The data were processed by content analysis. In the theoretical part, I focused on individual risk factors in the work environment of quarries and on health risk assessment. In the practical part, I compared the measurement results with the health limits set out in Government Regulation No. 361/2007 Coll. laying down the conditions of health protection in the workplace, as amended, and in Government Regulation No. 272/2011 Coll. that lays down hygienic limits of noise and vibration. Individual professions were categorized according to Decree No. 432/2003 Coll., as amended. The factors assessed in the work environment of quarries were quarry dust, total and hand-transmitted vibrations, noise and physical strain. The lowest rated factors include dust and total vibrations. Hygienic limits were not always observed, and thus the employer is obliged to take measures to protect the health of employees. The most important step in the development of quarries is the purchase of new, modern machines and the overall modernization of production, resulting in reduction of the workers´ exposure to risk factors.
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