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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

Návrh vírové turbiny pro konkrétní lokalitu ČEZ,a.s / The design of swirl turbine for the concrete locality for ČEZ

Šebela, Radek January 2014 (has links)
This thesis deals with the design of water turbine enabling optimal utilization of hydro-energetic potential of given location (barrage on Úpa river) chosen by ČEZ a.s. company. Moreover, the option of multi-unit layout is discussed. Because of the low-head profile of given location, the technology of swirl turbine in siphon configuration was chosen. Technology of swirl turbine presents new modification of Kaplan turbine with no need of guide vane. Swirl turbine is characterized by its high discharge and high speed. The main part of this thesis is focused on hydraulic design of the turbine.
12

Řízení proporcionálního hydraulického ventilu / Control of proportional directional control valves

Hoferek, Martin January 2017 (has links)
The thesis deals with design and implementation of proportional hydraulic valve, which will be integrated to hydraulic system of small hydro in Rájec - Jestřebí. This valve will be used to control one of the wicket gates of double Francis turbine. The thesis is processed for the company Mavel a.s., which is the owner of SH. The goal of this thesis is to create control of the valve according to the client's requirements, its implementation to the control system and commissioning.
13

Quantifying Localized Muscle Fatigue of the Forearm during Simulations of High Pressure Cleaning Lance Tasks

Quinones-Vientos, Sandra 30 January 2006 (has links)
Localized muscle fatigue (LMF) has been proposed as a surrogate measure to injury, since the onset of fatigue is rapid rather than months or years required to the onset of work related musculoskeletal disorders (WMSDs). The objectives of this study were to estimate LMF and quantify muscle activity of select forearm muscles during simulations of high pressure cleaning lance tasks common in the chemical production industry. Twenty participants, twelve males and eight females, with no musculoskeletal injuries and meeting criteria for upper extremity fitness, performed the simulated task. Independent variables studied include work height (shoulder, waist, and knuckle), lance orientation (parallel to the operator and parallel to the ground), and duty cycle (33, 50, and 67%) based on task analyses of actual work tasks. Dependent variables included mean RMS and rates of change in mean RMS, mean and median power frequency, MVE, and subjective ratings of fatigue. Repeated measures ANOVA was used to test the main effects of the independent variables and appropriate interactions. In general it was found that working at waist height, at higher duty cycles, and with the lance oriented parallel to the operator resulted in higher fatigue measures. Subjective ratings of fatigue were not well correlated with objective measures, similar to findings in previous studies. The simulated task was found to be extremely fatiguing and modifications to task design or job rotation schedules are required to reduce risk associated with injury development. / Master of Science
14

Entwicklung eines Modells dynamisch-muskulärer Arbeitsbeanspruchungen auf Basis digitaler Menschmodelle

Mühlstedt, Jens 07 March 2012 (has links)
Arbeitswissenschaftliche digitale Menschmodelle werden als Werkzeuge virtueller Ergonomie zur Gestaltung menschengerechter Produkte und Arbeitsplätze genutzt. Der bislang nur qualitativ beschriebene Praxiseinsatz wird durch theoretische Analysen und eine empirische Studie systematisiert und darauf aufbauend werden die Schwachstellen der Systeme erörtert. Ein wesentlicher Ansatzpunkt für Weiterentwicklungen ist die Erarbeitung ergonomischer Bewertungsverfahren bzw. -modelle, insbesondere für Belastungen aufgrund von Bewegungen. Digitale Menschmodelle bieten das Potenzial, aus simulierten Bewegungsdaten und den damit zusammenhängenden Belastungen eine Bewertung der Arbeitsvorgänge zu generieren. In dieser Arbeit wird daher ein neues arbeitswissenschaftliches Bewertungsmodell für muskuläre Beanspruchungen erforscht, d.h. methodisch hergeleitet und evaluiert. Dazu ist ein Versuchsstand zur Standardisierung und Belastungserzeugung notwendig. In der darauffolgenden Laborstudie werden die Belastungsparameter statischer Momentanteil, Winkelgeschwindigkeit und Momentrichtung variiert und die daraus entstehende Veränderung der muskulären Beanspruchung von Probanden erforscht. Ein dafür benötigtes, neues Verfahren zur Normalisierung wird vorgestellt. Die Laborstudie zeigt, dass der statische Momentanteil linear steigend mit der Arbeitsbeanspruchung zusammenhängt. Die durchschnittliche Winkelgeschwindigkeit beeinflusst die Arbeitsbeanspruchung je nach Muskeltyp entweder linear steigend oder ohne Zusammenhang. / Digital human models for human factors are used as tools for virtual ergonomics and the design of products and workplaces. In this work the use of the systems is analysed with theoretical models and an empirical study. Therefore, disadvantages of the systems are identified. A main idea for further developments is the research on ergonomic approaches and models, especially for movements and the strain caused by movements. Digital human models are capable to assess work processes based on data from simulations. In this work a new human factors orientated rating model for muscular strains is developed and evaluated. A test stand generates and standardizes the stress. In a laboratory survey the stress parameters are analysed. The variation of the static torque part, the angular velocity and the torque direction cause changes in the muscular strains. Hence, these muscular strains are measured electromyographically. A new normalisation method, the normalized standard movement, is introduced. The survey shows the existence of a correlation of static torque part and work strain. Depending on the muscle type, the angular velocity either affects the work strain linear increasing or does not affect it.
15

Evaluation Of Register Allocation And Instruction Scheduling Methods In Multiple Issue Processors

Valluri, Madhavi Gopal 01 1900 (has links) (PDF)
No description available.
16

Tvorba a estimace modelu malé vodní elektrárny v programu PSCAD / Creation and estimation of small hydro power plant model in PSCAD

Razyapova, Aygul January 2018 (has links)
This thesis focused on creating a model of a small hydropower plant model (SHPP) and a part of the electricity network in the simulation software "PSCAD" (basing on real sources). The model will be specified on the basis of the data obtained from the measurements to correspond with the real equipment.
17

變數轉換之離群值偵測 / Detection of Outliers with Data Transformation

吳秉勳, David Wu Unknown Date (has links)
在迴歸分析中,當資料中存在很多離群值時,偵測的工作變得非常不容易。 在此狀況下,我們無法使用傳統的殘差分析正確地偵測出其是否存在,此現象稱為遮蔽效應(The Masking Effect)。 而為了避免此效應的發生,我們利用最小中位數穩健迴歸估計值(Least Median Squares Estimator)正確地找出這些群集離群值,此估計值擁有最大即50﹪的容離值 (Breakdown point)。 在這篇論文中,用來求出最小中位數穩健迴歸估計值的演算法稱為步進搜尋演算法 (the Forward Search Algorithm)。 結果顯示,我們可以利用此演算法得到的穩健迴歸估計值,很快並有效率的找出資料中的群集離群值;另外,更進一步的結果顯示,我們只需從資料中隨機選取一百次子集,並進行步進搜尋,即可得到概似的穩健迴歸估計值並正確的找出那些群集離群值。 最後,我們利用鐘乳石圖(Stalactite Plot)列出所有被偵測到的離群值。 在多變量資料中,我們若使用Mahalanobis距離也會遭遇到同樣的屏蔽效應。 而此一問題,隨著另一高度穩健估計值的採用,亦可迎刃而解。 此估計值稱為最小體積橢圓體估計值 (Minimum Volume Ellipsoid),其亦擁有最大即50﹪的容離值。 在此,我們也利用步進搜尋法求出此估計值,並利用鐘乳石圖列出所有被偵測到的離群值。 這篇論文的第二部分則利用變數轉換的技巧將迴歸資料中的殘差項常態化並且加強其等變異的特性以利後續的資料分析。 在步進搜尋進行的過程中,我們觀察分數統計量(Score Statistic)和其他相關診斷統計量的變化。 結果顯示,這些統計量一起提供了有關轉換參數選取豐富的資訊,並且我們亦可從步進搜尋進行的過程中觀察出某些離群值對參數選取的影響。 / Detecting regression outliers is not trivial when there are many of them. The methods of using classical diagnostic plots sometimes fail to detect them. This phenomenon is known as the masking effect. To avoid this, we propose to find out those multiple outliers by using a highly robust regression estimator called the least median squares (LMS) estimator which has maximal breakdown point. The algorithm in search of the LMS estimator is called the forward search algorithm. The estimator found by the forward search is shown to lead to the rapid detection of multiple outliers. Furthermore, the result reveals that 100 repeats of a simple forward search from a random starting subset are shown to provide sufficiently robust parameter estimators to reveal multiple outliers. Finally, those detected outliers are exhibited by the stalactite plot that shows greatly stable pattern of them. Referring to multivariate data, the Mahalanobis distance also suffers from the masking effect that can be remedied by using a highly robust estimator called the minimum volume ellipsoid (MVE) estimator. It can also be found by using the forward search algorithm and it also has maximal breakdown point. The detected outliers are then displayed in the stalactite plot. The second part of this dissertation is the transformation of regression data so that the approximate normality and the homogeneity of the residuals can be achieved. During the process of the forward search, we monitor the quantity of interest called score statistic and some other diagnostic plots. They jointly provide a wealth of information about transformation along with the effect of individual observation on this statistic.
18

Alternativní řešení a pevnostní kontrola mechanických česlí / Alternative solution and strength check of mechanical screens

Sommer, Matěj January 2020 (has links)
This master’s thesis deals with a new design of bar screens. The goal was to come up with an alternative design to already existing device by INKOS a. s. In the first part, there is a summary of various machines working in similiar conditions. The insights gained by this research influenced the design of the new device. It utilizes well proven solutions from previous projects, but some of these were reworked and a few new functions were added. Second part of the thesis describes the analytical solutions, which were used to determine the forces in the assembly during the operation of the device. Based on the results of these calculations, a strength analysis of important components was performed using the finite element method. The result of this thesis is the design and optimization of new bar screens, including engineering drawings and tools for its further development.

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