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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Měření a analýza vibrací systémem OCTAVIS / Measurement and analysis of vibration with OCTAVIS system

Pařík, Zdeněk January 2011 (has links)
This thesis is focus at diagnostics of processing machines by diagnostics of vibration with the OCTAVIS system. There is mentioned a view of the present vibration monitoring methods, description of developed diagnosis bench, measuring in this bench and measuring of the chosen production machine.
12

Ohybové vibrace hnacího ústrojí nákladního vozidla 8x8 / Bending Vibrations of 8x8 Heavy Duty Truck

Knotek, Jiří January 2013 (has links)
The aim of this thesis is an analysis of bending vibrations of the heavy duty truck transmission and a design of construction modifications. The next target is to evaluate the contribution of the construction modification. In the thesis is also performed analysis of shaft support stiffness.
13

Detekce reologických změn axiálního systému gravidních žen pomocí metody TVS / Detection of rheological changes in the axial system of pregnant women using the TVS method.

Plačková, Veronika January 2014 (has links)
Title: Detection of rheological changes in the axial system of pregnant women using the TVS method. Objectives: The aim of this thesis is to evaluace the effect of pregnancy on the biomechanical properties of the spine. Methods: TVS vibration diagnostic methods were applied to six pregnant women twice during pregnancy. It was investigated ability of axial system to dampen vibration spreading through out the spine. The ability of every single segment to damp vibrations were compared with each other at the beginning and during pregnancy. Results: TVS method used for purpose of this paper has been proved adequate to provide information about the resonant frequencies and the total attenuation of the spine with sufficient accuracy, so that the biomechanice changes of axial system during pregnancy could be decidly identified. Comparison of the frequency dependency and total attenuation of spine indicated increase of total attenuation of the spine and also increase of flexibility of the spine in all investigated probands. Keywords: gravidity, pregnancy, axial system, vibrations, TVS, spine
14

Vliv vibrační terapie na posturální stabilitu u pacientů se syndromem Charcot-Marie-Tooth / Effect of whole body vibration therapy on postural stability in Charcote-Marie-Tooth.

Jindrová, Barbora January 2016 (has links)
Objective: Charcot-Marie-Tooth disease (CMT) is the most common hereditary motor and sensory neuropathy. Genetic mutation causes neurological disorder of peripheral nervous system. Diseases most common signs and symptoms are distal muscle weakness, foot deformities and somatosensory defect. One of the most notable consequences of the disease is balance disorder. The goal of this study was to ascertain impact of one-off application of vibration therapy on postural stability in CMT and referential group. Method: There were 16 patients diagnosed with CMT that participated in the research, 15 of which finished all procedures (average age 44.3 years, age ranges from 25 to 57 years, 12 woman and 3 men). Referential group was composed of healthy people of similar sex and age. All probands underwent measuring on Balance Master before vibration therapy, immediately after and 30 minutes later. The therapy take place in standing position in the Power Plate, therapy lasted for 5 minutes. Results: A significant improvement of Endpoint Excursion, Maximum Excursion, Movement Velocity and Sway velocity parameters was established after applying one-off vibration therapy in group of patients diagnosed with CMT. This effect endured 30 min after vibration therapy. Also we discovered that vibration therapy has stronger...
15

Elektromyografická analýza vlivu vibrační čínky na vybrané svaly horní končetiny / Electromyographic analysis of the influence of vibrating dumbbell on upper extremity muscles

Loučková, Zuzana January 2012 (has links)
Title: Electromyographic analysis of the influence of vibrating dumbbell on upper extremity muscles Objective: The main purpose of this study was to compare the electric activity of m. biceps and triceps brachii, and upper and lower part of m. trapezius, during exercises both with a vibrating dumbbell, and a dumbbell without vibrations. Furthermore, our objective was to compare the muscle activity during static stress (dumbbell kept in one position), and dynamic stress with the vibrating dumbbell (moving in the elbow joint). Methods: Surface electromyography was chosen as an objectification method. Nine healthy women of age between 23 and 26 years participated in this study. A dumbbell of 1, 5 kg weight, 36 Hz vibrating frequency and 1,3 mm amplitude was used. Results: An increase of electrical activity can be observed in all assessed muscles when stimulated with vibrations. However, this increase can be considered as statistically significant only in case of static stress of the m. biceps and triceps brachii. Results also indicate high activity of the upper part of m. trapezius during exercise with activated vibrations. Key words: vibrations, vibrating dumbbell, vibration training, electromyographic analysis
16

Identifikátory hypokinetické zátěže při řízení automobilu / Identificators hypokinetic load by driving

Tluchořová, Terezie January 2013 (has links)
Title: Hypokinetic load Identificators by driving vehicle Objectives: Development and testing of methods for determining changes in the mechanical parameters of the axial system of professional long-distance drivers. Design and testing procedure for clinical and physical examination sensitive to changes, that occur due to vibration and static load when driving the truck. Methods: TVS method, morphology of the spine, measurement of vibration exposure Results: TVS method that was used in the thesis has proved to provide information on the resonant frequency of the resonant frequency and the total attenuation of the spine with sufficient precision to ride their influence was clearly identifiable. Used accelerometer measurement of oscillations vibrational excitation spine has also proved applicable and provides objective parameters. Keywords: TVS method, vibration, hypokinesia, acceleration, driving, LBP
17

Pilový kotouč v procesu podélného řezání materiálů na bázi dřeva

Veselý, Přemysl January 2014 (has links)
In this dissertation thesis there is listed characteristics of circular saw blades, their distribution, influence of construction adjustments on final behavior of blade in the process of machining, problematic of oscillation of blades a mutual interaction among quality of machined surface, noise and dust. The thesis covers the problems of oscillation of circular saw blades as when idling and operating - the cutting process; and by the use of three circular saw blades with different construction modifications. These aforementioned construction measures are also compared to each other due to the implementation of standard construction saw blades not only from the perspective of oscillation, but also from the perspective of the roughness of the machined surface and the analysis of wood waste generated during cutting and noise. In the theoretical part there is an analysis of available literature and scientific theses. It outlines the particular publications devoted to methods of determining the shapes of oscillation, determining critical, resonant and recommended speed, blade constructions, including possible modifications, the theory of cutting saw blades including determining the size and shape of the splints and the effects of noise on the work environment. An important part of this work is methodology involving direct measurements for detection of unstable states of discs (resonance and critical speed. In this section it is further evaluated measuring of the oscillation of the test saw blade and verification of the proposed methodology with a different and practiced, commonly known method, so called cold shapes: The author also seeks to explore and determine the effect of different tooth pitch and method of execution of slots along with soundproofing grooves on noise levels, the resulting quality of the machined surface of various wood. The generated waste is then analyzed for splitting wood particles in particular size group with the percentage of each chip. The results of the experiment are in discussion confronted with the available scientific theses, taking into account with normal operating conditions, of which the conclusion is drawn.
18

Design pracovního stroje pro zhutňování krajnic / Design of the Machine for a Roadside Compacting

Šoltysová, Michaela January 2018 (has links)
Subject of this master thesis deals with the concept of the machine for a roadside compacting. After analysing of current market situation the aim of this work is not only to replace the vibration plate by new machine with a cab and vibration rollers but also mainly the design of the machine. The reason is easier work and it fulfils all constructional and ergonomic requirements and puts emphasis on aesthetic. So it fills a gap in the market.
19

Sběr energie pomocí MEMS / MEMS based energy harvesting

Klempa, Jaroslav January 2019 (has links)
This work is dedicated to principles of energy harvesting or scavenging from free energy around us. Energy harvesting principles are described in the first part. Following chapter is devoted to description of piezoelectricity and piezoelectric materials. Next part researches already reported results on piezoelectric energy harvesters. Following chapter shows simulations on designed structures in ANSYS® Workbench. Next the fabrication of the structures is described. Measurement are made regarding to maximum generated power.
20

Analýza kompozitního sendvičového panelu za podmínek simulujících umístění na raketovém nosiči / Analysis of composite sandwich panel under conditions simulating placement on a rocket carrier

Král, Martin January 2020 (has links)
This work deals with composite sandwich panels, which are currently used as supporting structures for satellites. This type of panel contains an aluminum honeycomb core and two thin laminate coatings, reinforced with carbon fibers. Laminate sandwich panel coatings offer an alternative to conventional aluminum coatings, which is advantageous mainly due to the reduction of weight and increase of the flexural stiffness of the panels. The work is a parametric study of mechanical properties for several variants of the coating of sandwich panels. These are laminate coatings, differing in the orientation of the fibers in the individual layers, as well as an aluminum alloy coating. The study is divided into two parts. The first part examines the deformation-stress response of a sandwich panel, which is simply supported at the edges and loaded with pressure. The response calculation is performed using FEM and verified by the method of sum of an infinite series. The second part investigates the deformation-stress response of the joint, (node) of two sandwich panels, which is loaded by random vibrations, aimed at simulating the mechanical environment of the rocket carrier during the takeoff of the launch vehicle. The response is calculated using FEM and verified by an experiment on a vibrating stool for a selected variant of the laminate coating of sandwich panels. The results of the work can be used for the design of baffle of the X-ray imaging device (SXI), which is part of the equipment of the space satellite of the SMILE project.

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