National Repository of Grey Literature 352 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
The objectivization of evaluation of the dynamics of self-defense instruments
Beránek, Václav ; Šťastný, Petr (advisor) ; Pavlů, Dagmar (referee) ; Reguli, Zdenko (referee)
Title: The objectivization of evaluation of the dynamics of self-defense instruments Introduction: Strikes by the upper limb are key tools for the self-defense system. So far, mechanical properties have not been evaluated for a wider group of strikes without protective equipment with applications in training, injury risk assessment, forensic biomechanics and medical law. Objectives: The aim of this work is to compile and objectify the evaluation of the dynamics of a wider group of strikes by the upper limb by specifying the size of the contact area and describing the damping properties of the foam of the detection apparatus. The aim is to evaluate the impact force, the probability of exceeding the bone tissue fracture threshold, the impulse, the size of the impact surfaces and the pressure for three impact techniques, both sexes and two experience levels. Methods: The work consists of three projects. Two quasi-experiments were completed by 169 probands, men and women, experience levels beginner, advanced (n = 169, height 177.8±9.0; weight 81.6±17.8; age 27.3±8.1) within one period. Probands were measured on two devices (Kistler, Podokam), where the time, impact force of the blow was recorded and three segments of the upper limb were photographed. Probands performed 3 striking techniques, a total of...
The Plant Experimental Models in Centuries - till 1918
Bršťáková, Hana ; Krtková, Jana (advisor) ; Lipavská, Helena (referee)
By 1918, many studies in plant organisms were performed. These laid fundamental building blocks for today's advanced research. To perform the experiments, many plant species were used. My thesis describes, first, which plant species were used in the experiments and second, what kind of discovery was made using them. I focus on plant processes and research fields that were of interest for the scientists then and this strucrure is also followed in my thesis. Each chapter describing individual process or research field is then written in chronological order. Specifically, the discovery of plant cell, selected plant movements such as nutation, phototropism, gravitropism, hydrotropism, plant nutrition and also the first scientific observation of Arabidopsis thaliana are discussed. The goal of this thesis is to introduce the history of selected discoveries in plants and to explain in which plant species the appropriate findings were achieved.
Goniometric functions in physical applications
Hanzlík, František ; Kvasz, Ladislav (advisor) ; Mošna, František (referee)
This Bachelor thesis gradually presents the properties of goniometric functions as part of physical phenomena which really exist and which people make use of. The phenomena are introduced in four separate chapters named after the experiments which are their central theme. The first chapter describes the movement of the body along the inclined plane. There is shown how we can use such movement to find separate points which lie on the tangent function. However, since all four basic goniometric functions can be expressed by just one function, for example the cosine function, of which the graph is a sinusoid, all next chapters deal with the sinusoid. For the first time it is plotted in the second chapter where are demonstrated some rules of the movement of the harmonic oscillator over time. In this thesis, important sinusoid transformations are also indicated. There is shown that the graphs of sinus and cosine functions differ only in their displacement. Thereby are those functions interlinked to each other. In the third part, when describing the effects of centrifugal acceleration on bodied located on Earth, some other features of the cosine functions are given, making use of the fact that the size of the centrifugal acceleration depends on the cosine of the angle which indicates the latitude. In that...
Bladeless fan cooling module
Šišpera, Adam ; Vacula, Jiří (referee) ; Bazala, Jiří (advisor)
Tato diplomová práce se zaměřuje na prozkoumání možností implementace bezlopatkového modulu ventilátoru založeného na Coanda efektu v chladícím systému osobního vozidla. Jejím cílem je prozkoumat proveditelnost takového řešení, jeho provozní charakteristiky a stanovit soubor doporučení pro návrh konkrétního designu. Vhodný chladící modul je navržen, následně hlouběji testován a jeho funkčnost je ověřena také reálným experimentem.
Flow Induced Vibration
Sázavský, Jakub ; Pochylý, František (referee) ; Habán, Vladimír (advisor)
When a fluid flows around a solid body, it interacts with each other. Flow-induced vibrations may occur. This is an undesirable phenomenon which is particularly dangerous due to the potential for resonance. Measurement of such induced vibrations is difficult. The aim of this paper is to design an expedient experiment, to evaluate the flow-excited vibrations and pulsations and to attempt to determine the uncertainties. Measurements are made in a special test section, the cavitation tunnel, on a hydraulic profile at different flow rates and rotation angles. The blade is measured by two laser vibrometers supplemented by a piezoelectric pressure gauge. The acquired data are processed using an own program in MATLAB software. The output is individual frequency spectra and summary graphs. The realized measurements are evaluated with orientation to the necessary signal processing to obtain relevant results.
Methodology for Determining the Dynamic characteristics of a Turbocharger Pneumatic Actuator
Hálek, Dominik ; Kocman, František (referee) ; Novotný, Pavel (advisor)
This diploma thesis is dealing with design of Methodology for Determining the Dynamic characteristics of a Turbocharger Pneumatic Actuator. Pneumatic Actuator is used as a control mechanism in turbocharged internal combustion engines, which affects the engine performance, efficiency and fuel consumption. Main aim of this thesis is to develop a systematic comprehensive procedure for collecting and analysing measured data of dynamic behaviour of this actuator. In the first part of the thesis, an experimental method is designed and implemented to measure the data required to analyse the dynamics of the actuator at different variations of pressure, displacement and frequency settings. A measurement chain with appropriate sensors is built and a software environment for data acquisition and storage is developed. In the second part of the thesis, the experimentally measured data are evaluated using mathematical model in Matlab software environment to extract stiffness and damping values from measured data and determine their dependence on frequency, pressure and displacement.
Boundary layer transition visualization in aerodynamic tunnel
Holík, Denis ; Trusík, Vojtěch (referee) ; Popela, Robert (advisor)
The purpose of the thesis was to propose and test an imaging method that allows visualization of the transition of a laminar boundary layer to a turbulent one and visualization of laminar boundary layer separation on the side mirror of a car. The beginning of the paper discusses the theoretical foundations associated with boundary layer formation and its evolution under various conditions. Afterwards, a survey of existing imaging methods that allow the display of flow on the surface of bodies was carried out. Of these methods, imaging using a thermal imaging camera was selected on the basis of the specified characteristics. The method using oil film (oilflow) was chosen as a control. Using both methods, experiments were conducted to confirm the suitability of the thermal imaging method for visualizing the transition of a laminar boundary layer to a turbulent boundary layer. The final test revealed the presence of laminar boundary layer separation on the upper cover of the car side mirror. At the end of the thesis, possible errors associated with the two chosen visualization methods were summarized, and ways to incorporate the thermal imaging method into automotive testing were proposed.
Technological Solution of the Rough Superstructure of the Municipal House U Muchů
Bystričan, Daniel ; Porwisz, Ondřej (referee) ; Mohapl, Martin (advisor)
The main goal of my bachelor's thesis is the construction-technological solution of the rough superstructure of the Municipal House U Muchů, which is located in the village of Dolní Město near the larger town of Humpolec in Vysočina. This work contains a technical report for the given technological stage, the situation of the construction with wider relations of transport routes, a statement of dimensions for the technological stage, a technological regulation including a balance of resources (item budget together with a graph of the deployment of workers). Furthermore, the content of this work is a drawing of the construction site equipment together with a technical report and construction organization solution for the rough superstructure, a timetable for the given stage, a design of the machine assembly including a comparison of two variants and the selection of the most suitable machine, control and test plans and ensuring work safety. In the last point of this work, I am dedicated to verifying the adhesion and load-bearing capacity of the connecting material, more specifically, it is a polyurethane adhesive for masonry.
Test dummy validation - differences in human mechanical response
Literová, Lucie ; Jelen, Karel (advisor) ; Šorfová, Monika (referee)
Title: Validation of the test dummy - differences in human mechanical response Objectives: The main goal of this thesis was to verify the usability of the Dummy Hybrid III for crash tests in the transport industry (the front and side directions). Methods: In the presented thesis, experimental methods were used to achieve the goal. The measurement of small impacts in laboratory conditions was carried out using the pendulum of the Department of Anatomy and Biomechanics of the UK FTVS. The measurement was performed on humans as well as on the Dummy Hybrid III. We monitored the reactions in the thoracic spine (thoracic vertebra Th5) and on the top of the head after impacts by a pendulum on certain areas on the human body/dummy. Impacts were delivered in four different intensities to the forehead, temporal bone, chest, shoulder and thigh. The measured impact quantity was the impact velocity. The observed magnitude of the response on the human body and dummy was the magnitude of the resulting acceleration in the area of the Th5 thoracic vertebra and the top of the head. Results: The results of this work have expanded the knowledge in the field of crash tests in the transport industry. Thanks to the obtained results, there was verified the suitability of the laboratory model of the pendulum for further...
Chemical experiments in the home environment and their didactic processing
Koběrská, Klára ; Teplá, Milada (advisor) ; Stratilová Urválková, Eva (referee)
Klára Koběrská: Chemical experiments in the home environment and their didactic processing. Bachelor thesis. Prague: Faculty of Science, Charles University, 2023. Abstract The bachelor's thesis focuses on home experiments in chemistry and their didactic processing. The theoretical part defines the concept of experimental teaching of chemistry, its function, and its concept in obligatory pedagogical documents. It also includes the involvement of chemical experiments in distance learning and the safety of practical chemistry teaching outside the laboratory environment. The thesis aims to conduct research and evaluate available didactic materials on the topic, thus evaluating the didactic processing, availability, safety, age of students, and relation to RVP, as well as the time demands of 16 materials. Based on the research findings, the practical part presents 5 worksheets for students supplemented with methodological instructions for teachers. These didactic materials were evaluated by 10 teachers and 69 students throughout the questionnaire, and their comments were considered in the final adjustment of the set of worksheets. Key words chemistry, experiment, didactic materials, homeschooling, elementary schools, high schools, set of experiments

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