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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.
361

Implementace a aplikace metody párování obráběných materiálů a břitů při orbitálním vrtání / Implementation and application of the edge-material pair methodology at orbital drilling

Saillet, Alan January 2018 (has links)
This internship's objective is to implement modeling of uncut chip thicknesses and milling forces in 3-axis milling, and apply it to orbital drilling. The goal is to understand deeper the process, and develop a tool which permits to model a wide range of end-mill tool geometries, and most of 3-axis milling operations.In this report, the following axis will be developed: • The modeling of the complex tool geometry • The modeling of uncut chip thicknesses in slot milling, and for any 3-axis milling operation • The strategy which has been chosen to identify cutting forces coefficients, and their use. • The obtained results and prospects for development.
362

The Potential Effects of Exercise-Induced Cortisol Release on Executive Functioning in Preadolescents

Bettencourt, Kory Matthew 01 January 2018 (has links)
Purpose: Moderate-intensity aerobic exercise (MAE) has been shown to elicit improvements in cognition and subsequent academic performance among preadolescents. Aerobic exercise has also shown to increase cortisol release in response to increasing exercise intensity. However, it is unknown if increased cortisol levels following exercise are related to acute improvements in executive function following a bout of MAE in preadolescents. The purpose of this study was to examine the potential effects of increased cortisol release after acute MAE on attention and working memory among preadolescents. Methods: Eleven preadolescents [6 males, 5 females] volunteered to participate in this study (age=9.45±1.03). Participants were randomized in a counterbalanced fashion to 30 minutes of rest or 30 minutes of treadmill MAE (60-70% HR max). Immediately pre-post each condition, participants completed a cognitive battery consisting of tests of attention (Flanker Test) and working memory (List Sorting Working Memory Test), as well as salivary samples for the analysis of cortisol. Linear Regression models were used to assess significance of covariates. Generalized linear models were used to assess significance of changes in each dependent variable against time, condition, time*condition and change in cortisol. Tukey’s HSD post-hoc tests for multiple comparisons were used to assess the effect of condition on working memory, attention, and salivary cortisol. Results: There was a significant effect of condition on working memory (F=3.16, p =0.04), with no change from pre-post rest (p=0.93) and improving from pre-post exercise (p=0.04). There was no effect of condition on attention or salivary cortisol, most likely due to a small sample size. Multiple linear regression models showed a significant effect of age (p=0.03) and change in cortisol (p=0.007) on working memory. Conclusion: Exercise had a positive effect on working memory, however, we were unable to relate this improvement to changes in salivary cortisol due to a lack of statistical power. This study could provide insight into the physiological effects of increased cortisol release on cognition, specifically in regard to working memory. However, more data are needed to achieve sufficient statistical power to detect these relationships.
363

Řídicí systém jevištní divadelní techniky / Theatre Stage Technology Control System

Melo, Damián January 2013 (has links)
The topic of the diploma thesis is control of theatre stage devices. The basic types of control, methods for description and identification of systems and properties of regulators are discussed. Project includes description of theatre technogy and proposal for an appropriate control system. Also, a axis controller was implemented and tested on a real stage device.
364

Manipulátor pro manipulaci s vysokotlakovými láhvemi / Manipulator for manipulation with pressure bottles

Machovský, František January 2008 (has links)
Subject of this thesis is elaborating of complete documentation drawings which is preceded introductionary studies with analysis of possible variants. Thesis is underseting stress and control calculations. In conlusion is elaborating economical evaluation of project. Documentation drawings is in annex.
365

C osa u svislého soustruhu / C axis for vertical turning machine

Solař, Martin January 2008 (has links)
The subject of my thesis is a constructional proposal of C axis drive for vertically orientated machine. I have concerned the drive operates C axis of revolving slide. The thesis contains the cutting power study regarding the power being in effect during C axis machining, study of clearance adjustment in particular mechanisms, three constructive proposals of possible solutions, calculation of basic proposals’ demands as well as the best option selection which ideally fits to the all conditions requested by TOSHULIN, Inc.
366

Konstrukce multifunkčního obráběcího centra / Design of multi-functional machining centre

Gruník, Jan January 2011 (has links)
This work deals with the construction and describes a detailed calculation of a machine frame of the shaft-turning lathe and 2D axis passes including the underpass according to the chosen initial parameters. The information contained in this work is not only of theoretical knowledge, but it should also serve for the practical use as a guide for the frames construction. The work also contains a background research on the topic, the model frame, the frame strength analysis, optimization of the frame, 2D axis, calculation, design and implementation of the underpass and the whole assembly. A suggestion for the future procedure and optimizing of the existing structure is found in this work as well.
367

Konstrukce dvouosého solárního trackeru / The design of two axis solar tracker

Krejčí, David January 2011 (has links)
The purpose of this dissertation is to design the dual-axis solar tracker carrying the concentrator photovoltaic panels. The preamble of the dissertation shortly examines a photovoltaic cells development up to concentrators and the common support structures of solar power plants. The second part focuses on the engineering process itself. It includes the choice of the variant that suits best the requirements, the calculations of wind load and design of the various joints. The conclusion part is devoted to the evaluation, economy analysis of the construction and proposals for improvements.
368

Konstrukce horizontálního frézovacího a vyvrtávacího stroje / Design of horizontal milling and boring machine

Pavlíček, Alois January 2014 (has links)
This master thesis deals with the engineering design of a headstock floor type boring/milling machine. At first, background research of boring machines and accessories is performed. The type and parameters of the floor type boring machine are chosen according to the background research. In the next part the thesis deals with the individual structural units of the headstock. The thesis also contains a 3D model of the headstock and fine drawing documentation. The 3D model of the horizontal floor type boring machine has been converted into a virtual reality environment.
369

Aplikace víceosového frézování na obrábění tvarové součásti / Application of the multi-axis milling of a shaped part

Klíma, Jiří January 2015 (has links)
This diploma thesis focuses on the design and production technology of making pattern and core box by milling. The theoretical part summarizes the issue of production models, CAD / CAM technology and milling technology. The practical part is elaborates engineering design of machined parts focused on the specific requirements for application in the foundry. For designing of milling technology was used CAM system. This milling technology was programmed and optimized. Parts are finally produced on 3-axis milling machine. In the end there is technical-economic evaluation of production and discussion of results.
370

Využití parametrického programování pro obrábění obecných ploch / The use of parametrical programming for complex part machining

Skácel, Jan January 2015 (has links)
Thesis consists of theoretical introduction to programming in G-code, underlying mathematical principles and methods how to program general curves and surfaces. There are seven exam

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