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Powertrain Vibration Solution using Computational Modelling
Zubík, Martin ; Prokop, Aleš (referee) ; Novotný, Pavel (advisor)
The thesis solves vibration of simple combustion engine model as a basic step for evaluating the noise of engine. On the basis of computational model realized in software MBS ADAMS, which contains all significant input parameters, there are found normal velocities of the one cylinder four stroke engine block surfaces. The outputs are then processed into the integral characteristics that define the level of possible emissions for whole acoustic spectre. Two variants of the engine block were solved and in the end the summary of solution approach was made.
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Reological properties of cement pastes modified by amorphous SiO2
Zimmermann, Štěpán ; Rovnaník, Pavel (referee) ; Vyšvařil, Martin (advisor)
The subject of this thesis are the rheological properties of cement paste with the addition of amorphous silicon dioxide. The basic rheological parameters are that describe the behavior of cement pastes in the fresh state. The work also included rheological tests including measurement principle and method of evaluation. Effect of mineral admixtures with high content of amorphous SiO2 is summarized the available scientific articles. In the experimental part, the effects of impurities with a high content of amorphous SiO2 on the rheological properties of fresh cement paste. It was tested by substitution of up to 10 % by weight of cement in the cement pastes mineral admixtures of different chemical composition, particle size and pozzolanic activity. Flow measurement was measured yield value, viscosity, and flow index. The stability of cement pastes was investigated oscillatory measurements. To complement the behavior pastes in the fresh state was determined by calorimetry. Test results were compared with those determined by reference samples and compared the effect of various ingredients.
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Pendulum excitation
Vrána, Jiří ; Březina, Lukáš (referee) ; Hadaš, Zdeněk (advisor)
This thesis is focused on creating a model situation of excited pendulum with one degree of freedom that oscillates in both linear and nonlinear condition. The theoretical part describes several basic concepts of oscillation theory and states some examples of pendulum applicability. The practical part consists assembling of motion equations of model situations, based on which simulations programs are created. The thesis contains also concept of practical use of the nonlinear pendulum model.
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Principles and types of hydrodynamic valves
Havelka, Milan ; Himr, Daniel (referee) ; Pochylý, František (advisor)
This thesis deals with characteristics of the most commonly used valves in hydraulic systems. The aim was to create an overview of available features and define their brief characteristics. The emphasis was placed on their function and principles of task performance in a hydraulic circuit. The second part of the thesis is aimed at solving the issue of valves oscillation and subsequent optimization of constants that function as factor dampping.
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Oscillatory Power Generator Base on Mechanical Resonant Element
Mihalík, Vlastimil ; Houška, Pavel (referee) ; Hadaš, Zdeněk (advisor)
This work deals with the power supply of wireless sensors. When using a wireless sensor is desirable application of alternative energy sources, because the primary cells or batteries may reduce the extent or length of service of the sensor itself. Ambient energy can be used as a suitable alternative source. This energy must be in an appropriate form, which allows its conversion to electric energy. These appropriate, already used types include: solar en., temperature gradient en., en. of flowing liquids, vibration, etc. The advantage of vibrations is its presence in almost all mechanical systems. One of the possibilities for using the vibration of machine systems for power supply wireless sensors is using the vibration power generator with oscillating component. The generator must be designed so that its resonance frequency coincides with the frequency of vibration in the machine system. This method can be used only if the machinery system vibrations at least partially constant. Another option is to use the vibrations caused by, for example, transit transport, or different step acting factor. In this case, it is desirable that the generator is designed with variable resonant frequency, which can partly be achieved, for example, integrating several oscillating component in the body of generator. After the general analysis of the problem, graduation theses will be concerned with the possibility of use of energy from the short damped oscillation and step impulse. Focusing on a proposal of multi-element structures.
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Analysis of tuned mass damper
Jurečka, Martin ; Rubeš, Ondřej (referee) ; Kšica, Filip (advisor)
Complex mechanical structures are often exposed to external influences that can cause excessive vibrations, which can limit their ability to perform their function or affect operational safety. Tuned mass dampers, which are focus of this thesis are very often used to avoid such vibrations. The firts part of the thesis is focused on the research of the principle of tuned mass damper and its use in engineering practice. In the secound part obtained knowlage is used to create a mathematical model of the selected mechanical system and then to implement a suitably designed tuned mass damper to damp unwanted vibrations. Part of the work i also to build a real model of the tuned mass damper, which will demonstrate its function.
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Analysis of spontaneous synchronization of coupled mechanical oscillators
Nečesal, Filip ; Hadaš, Zdeněk (referee) ; Kšica, Filip (advisor)
The work explains and describes the behavior of synchronization of two mechanical oscillators. This phenomenon is demonstrated on a physical model and compared with a computational model in several experiments. My motivation was that it is a fascinating phenomenon, and the problem is close to me because of the field I study. It was based on the knowledge gained during my previous studies. The first part of the bachelor thesis deals with the research on the synchronization of mechanical oscillators, the mathematical expression of individual types of oscillations, and their properties. The second part consists of a physic model of two pendulums on one base plate and a measurement of the system. The third part of the thesis contains a mathematical model, which was compared with the physical model in last part of the work.
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Detector of optical beam position
Lukáč, Vladimír ; Barcík, Peter (referee) ; Kolka, Zdeněk (advisor)
The bachelor's thesis deals with the design of an optical beam position detector with the required parameters. The aim was to select a suitable photodetector that captures light rays and converts them into photocurrent, to design photocurrent processing into a voltage signal with linear properties and specified parameters, to convert the analog form of the voltage signal into digital information with which a microcomputer or microcontroller can work. The analog part of the work is simulated in the program OrCAD PSpice, in which the functionality and correctness of the designs is confirmed. The digital part processes the voltage signal to the information of the used channel, its level displays this data on the display.
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Radical Experience and Thinking of Poetic Inspiration. The Body (without Organs) in Maurice Blanchot's Space of Literature.
Poch, Martin ; Ševčík, Miloš (advisor) ; Jarošová, Helena (referee)
Radical Thinking and Experience of Poetic Inspiration → Abstract Blanchot's radical thinking of writer's experience poses, but do not answer a question of its physical dimension. According to Blanchot, it seems as if the writer's experience was completely unbodied, so that it excludes the possibility of writing and realization of essential speech in the world. Our interpretation of Blanchot's key concepts proceeds with an attempt to solve this problem and present its main consequences. In the last section we operate some of the terms of Deleuze and Guattari - namely becoming, the body without organs - in order to conceive writer's experience as inherently differentiated process in which the body is absent, because - deprived of its organs - it becomes an imperceptible part of assemblage which enters the space of literature.
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Effect of sensomotoric insoles on postural stability in children with cerebral palsy
Bartošová, Simona ; Hráský, Pavel (advisor) ; Gryc, Tomáš (referee)
Author: Bc. Simona Bartošová Title: Effect of sensomotoric insoles on postural stability in children with cerebral palsy Objectives: Objectively assess the effect of sensomotoric insoles on children with cerebral palsy (CP) via COP (Centre of Pressure) parameters recorded on Kistler force plate. Methods: This thesis is designed as an experimental study. Selected paramaters of static postural balance were recorded via force plate to assess the effect of sensomotoric insoles. Five subjects (average age 7.2 years) with diagnosis of cerebral palsy were enrolled into the study. Data collection was carried out in two separated sessions - first before therapy and second after using the insoles for one month. The validity of the data was supported by three repetitions for each modification - upright plain stand with open eyes, upright stand with feet together and upright plain stand with closed eyes. Monitored parameters were: total trajectory of COP, amplitude of mediolateral displacement of COP, amplitude of anteroposterior displacement of COP and mean velocity of movement of COP. The data were analyzed in MATLAB® version R2019b. The statistical analysis was performed including the outliers elimination. The normality of data was checked by Lilliefors' test. In the case of normality a two-sample Student's...
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