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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.
1

Aerodynamický návrh posledního stupně parní turbíny / Aerodynamic design of the last stage of a steam turbine

Jeřábek, Lukáš January 2018 (has links)
Diploma thesis deals with calculations of a steam turbine with two uncontrolled extraction points according to the assignment, aerodynamics of the last two stages and operating range with respect to ventilation, range of performance and straining of the last blading under the large condensation pressure deviations. For the first three stages the calculation of prismatic action blades is executed. The fourth and the fifth stages are designed with inconstant reaction over the blades length and their calculation is executed with constant circulation method. For these stages, aerofoil design with respect to their aerodynamic qualities is carried out using Bézier curves. During the whole time verification process of aerofoils qualities, their energy losses and isoentropic Mach number distribution is executed in MISES program in cooperation with Doosan Škoda Power.
2

Automatická kontrola správnosti sestavení výrobku / Automatic Verification of Product Assembling Correctness

Doležal, Petr January 2010 (has links)
This diploma evaluates methods for verification of key characteristics of a product using digital image processing techniques. At first, reasons why this work has been done are described followed by a list of all methods that were used in this diploma such as Hough Circle Transform and Flood Fill (Seed Fill) algorithm. Also, a new approach how to compensate non regularly illuminated scene, which is based on surface modeling with Bézier Surfaces, was developed. Moreover, the algorithm was implemented in the C++ programming language and some of the parts were also simulated using the MATLAB environment. The algorithm was evaluated based on the percentage level of recognition of the required parameters. Efficiency of the implementation is also important for the author.
3

Extrakce a modifikace vlastností číslicových zvukových signálů v dynamické rovině / Digital Audio Signal Feature Extraction and Modification in Dynamic Plane

Kramoliš, Ondřej January 2010 (has links)
This thesis deals with basic methods of root mean square and peak value measurement of a digital acoustic signal, algotithms to measure audio programme loudness and true-peak audio level according to recommendation ITU-R BS.1770-1 and digital systems for control of signal dynamic range. It shows achieved results of root mean square and peak value measurement and results of implementation of dynamic processor with general piecewise linear non-decreasing static curve and algorithms according to recommendation ITU-R BS.1770-1.
4

Modifikace Navier-Stokesových rovnic za předpokladu kvazipotenciálního proudění / Modification of Navier_Stokes equations asuming the quasi-potential flow

Navrátil, Dušan January 2019 (has links)
The master's thesis deals with Navier-Stokes equations in curvilinear coordinates and their solution for quasi-potential flow. The emphasis is on detailed description of curvilinear space and its expression using Bézier curves, Bézier surfaces and Bézier bodies. Further, fundamental concepts of hydromechanics are defined, including potential and quasi-potential flow. Cauchy equations are derived as a result of the law of momentum conservation and continuity equation is derived as a result of principle of mass conservation. Navier-Stokes equations are then derived as a special case of Cauchy equations using Cauchy stress tensor of Newtonian compressible fluid. Further transformation into curvilinear coordinates is accomplished through differential operators in curvilinear coordinates and by using curvature vector of space curve. In the last section we use results from previous chapters to solve boundary value problem of quasi-potential flow, which was solved by finite difference method using Matlab environment.
5

Návrh odstředivého čerpadla metodami diferenciální geometrie / Design of Centrifugal Pump Using Differential Geometry Methods

Sloupenský, Zdeněk January 2011 (has links)
This thesis deals with a new approach to the design of impeller, blade and spiral of centrifugal pump. The mathematic model of flow inside meridional section of impeller and spiral is based on the instruments of differential geometry applied to Bezier surfaces. This formerly introduced theory is more deeply developed in this thesis and the conclusions are applied to the design of centrifugal pump parts working with fluid. The main thesis output is the mathematic model and on its principles created software determined for the design of impeller, blade and spiral. The received results are exportable into one of the commonly used 3D modeling programs.
6

Tutoriál Blenderu / Blender Tutorial

Tomšík, Filip Unknown Date (has links)
This thesis focuses on the increasingly popular shareware Blender which has growing application possibilities in various branches. The thesis aims at a general description of basic modelling techniques working with mesh objects as well as curves used for creating models and computer graphics. Part of the thesis is dedicated to a description of animation abilities of the programme, an outline of dierent methods and a more detailed description of correspondent modules. The central point of the thesis is to introduce the reader to the basic and advanced modelling techniques and their use in Blender, in the form of a tutorial.
7

Modelování NURBS křivek a ploch v projektivním prostoru / Modelling of NURBS curves and surfaces in the projective space

Ondroušková, Jana January 2009 (has links)
In the first part I discuss ancestors of NURBS curves and surfaces, rather Ferguson, Beziere, Coons and B-spline curves and surfaces and furthermore B-spline functions. In the second part I devote to NURBS curves and surfaces, their description as a linear combination of B-spline functions in the projective space. I specify conical arcs more detailed, their submit in the projective space and NURBS surfasec given as tensor product of NURBS curves. Last part is devote to describtion programs for modeling conicals and NURBS surface.
8

Tenkostěnné přesypané konstrukce / Flexible buried structures

Houšť, Vladimír January 2015 (has links)
The thesis is devoted to analysing of flexible buried arch structures. Modelling of the flexible concrete arch is carried out via a nonlinear finite element model that accounts for soil constitutive relations, soil-structure interactions, sequential construction stages and soil compaction. Advanced FE-model was verified by measurement obtained by full-scale field testing of two buried arches. Mathematical optimization methods of genetic algorithms and Levenberg-Marquardt method are applied to already calibrated complex computational models in order to reduce bending and associated flexural stresses in the concrete section of buried arch. Centre line of the arch is parameterized by cubic Bezier curve to reach interpolation of thrust line. Optimization technique is applied with extensive parametrical study which shows the optimal shapes for buried arches of various span/rise ratios, backfill depths and foundation soil types. For practical application are given coordinates of Bézier curve control polygons of particular resulting shape. Subsequently is applied optimization method for a theoretical reduction of tensile stresses obtained by shape optimization of previously verified numerical model of buried arch. Comparisons of earth pressure, bending moment axial force and deflection of flexible structure during sequential construction of different span/raise ratios of buried arches are presented. The behaviour of flexible buried arch with effect of local traffic load model LM1 has been analysed via 3D finite elements model with respect to different depth of backfill above crown.

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