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The pump with a diffuser with stochastic blades (runner and diffuser)
Dobšáková, Lenka ; Haluza, Miloslav (advisor)
This doctoral thesis studies the non-uniform blade cascade for centrifugal pumps. Influence of non-uniform blade cascade is investigated on the impeller and diffuser. A non-uniform blading impeller of pumps in this doctoral thesis was examined in terms of influence on efficiency characteristic. The idea of using non-uniform blading is to obtain a flat efficiency characteristic. Then the centrifugal pump could be used on larger scale of power with achieving a sufficiently high efficiency. The work is based on experimental measurements and numerical simulations of non-uniform hydraulic pump components. Non-uniform impeller and the diffuser were newly designed for this research. A new measuring track of small submersible pumps was needed to design and build for measurements. Different pump combinations with conventional hydraulics on one working point and hydraulics with non-uniform were measured. All measurements were evaluated and characteristics of efficiency, head and power were obtained for each measured combination. Some of pump combinations (which were measured in experiment) were numerically simulated by program Ansys Fluent. Data needed to evaluate the characteristic of efficiency and specific energy were collected from each numerical simulation. A theoretical consideration concerns the influence of non-uniform blade cascade applied on diffuser. The suggestion how to decrease hydraulic losses in canals was done. The theoretical consideration how to make a flat efficiency characteristic was made.
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Assesment of the Environmental Impact in the Design of Production Machines in Terms of Greenhouse Gas Emissions of Selected
Krbalová, Maria ; Pačaiová,, Hana (referee) ; Demeč, Peter (referee) ; Blecha, Petr (advisor)
The presented doctoral thesis is focused on environmental impact assessment of basic engineering materials used in a production machine construction. Ecological profile of the machine itself develops already in the phase of its design. It is not only about the choice of future machine parameters and materials that it is built from, but also about technologies used for its manufacture and operation conditions of the finished machine (consumption of energy and service fluids). The thesis occupies in detail with environmental impact analysis of the production machine design from the viewpoint of material production that mentioned machine consists of. The output from the performed analysis is methodology for evaluating of machine design from the viewpoint of greenhouse gas emissions. Created methodology enables evaluating of machine ecological profile and its possible adjustments even during pre-production stage. In the first part of the thesis the analysis of current legislation in the field of fighting against climate changes, reducing of products energy consumption and increasing of production machines energy efficiency is presented. Also in this part of the thesis description of methods that were used to achieve thesis goals is stated. Furthermore analysis of production machine as a system of structural components that fulfil the certain functions and description of used basic engineering materials are presented. The second part of the thesis is devoted to environmental impact analysis of the production machine design process. There the design process and environmental impact of machine design are described. This is followed by description of production machine life cycle and detailed analysis of undesirable substances emissions emitted during pre-production phases of machine life cycle (i.e. during the raw materials extraction and materials production). From this analysis the particular constituents’ pre-production phases which are sources of undesirable substances emissions (e.g. greenhouse gas emissions) were derived. The thesis also includes analysis of these constituents’ life cycles and description of electric power generation as a basic constituent of any phase of product life cycle. In this part of the thesis calculations of particular fuel type’s amounts that is required to produce 1 MWh of electric power and carbon dioxide amount produced during electric power generation are presented. The third part of the thesis contains created models of manufacturing processes of basic engineering materials and calculations of related emissions of selected greenhouse gases. The practical output from this part of the thesis is methodology that enables environmental impact assessment of machine design from the viewpoint of engineering materials used in its construction.
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Testing of Cutting Tools for Multi-Axis Machining at Machining Centres
Dvořáček, Jan ; Mrkvica, Ivan (referee) ; Janáč, Alexander (referee) ; Píška, Miroslav (advisor)
The thesis is focused on testing of the cutting tools for machining on five axis machine tools and possibility of implementation of designed experiments in this area. The theoretical section focuses attention on analysis of specific features during five axis machining, including chip cross section and particularity of tool testing under high speed cutting conditions with consideration of dynamic stability of cutting tools. In the thesis force loading of the tool is discussed as well as its measurement process, considering force development caused by tool wear and data analysis. Description of designed experiment and its application to the area of tool testing is included as well. All theoretical predictions are followed by experimental verifying by extensive number of experimental tests, including evaluation of cutting tool condition, influence of hard coatings on cutting power of the tools, etc. For each of testing conditions are designed specific methods of processing of gathered data as well as evaluation of power of the cutting tools. Gathered data were processed by means of statistical evaluation and by statistical methods of designed experiments. The thesis contains also the extensive number of records and analysis, documented by means of light microscopy as well as electron microscopy.
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Testing of cutting tools for multi-axis machining at machining centres
Dvořáček, Jan ; Píška, Miroslav (advisor)
The thesis is focused on testing of the cutting tools for machining on five axis machine tools and possibility of implementation of designed experiments in this area. The theoretical section focuses attention on analysis of specific features during five axis machining, including chip cross section and particularity of tool testing under high speed cutting conditions with consideration of dynamic stability of cutting tools. In the thesis force loading of the tool is discussed as well as its measurement process, considering force development caused by tool wear and data analysis. Description of designed experiment and its application to the area of tool testing is included as well. All theoretical predictions are followed by experimental verifying by extensive number of experimental tests, including evaluation of cutting tool condition, influence of hard coatings on cutting power of the tools, etc. For each of testing conditions are designed specific methods of processing of gathered data as well as evaluation of power of the cutting tools. Gathered data were processed by means of statistical evaluation and by statistical methods of designed experiments. The thesis contains also the extensive number of records and analysis, documented by means of light microscopy as well as electron microscopy.
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Multi-Conductor Model of Communication over Outdoor Power Lines
Franek, Lešek ; Steinbauer, Miloslav (referee) ; Vozňák, Miroslav (referee) ; Fiedler, Petr (advisor)
PLC - power line communication is not new. It has been known for many years. But It never be used in massive scale. There were only sporadic applications, for example ripple control system HDO used in the Czechoslovakia. PLC currently experiencing a renaissance thanks to the advent of Smart Grid. PLC offering relatively low bit rates and relatively unreliable transmission, but these disadvantages compensates very low costs to build a communication infrastructure and it offers specific functionalities for Smart Grid. The question is whether the declared parameters will be met in the real world. This thesis tries to find an answer.
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Models of territorial self-government funding from the view of delegated powers
Jirouchová, Michaela ; Matula, Miloš (advisor) ; Topinka, Lukáš (referee)
This diploma thesis evaluates models of territorial self-government funding from the view of delegated powers in the Czech republic. To reach this goal, thesis is divided into four separated chapters. First chapter defines the function of local government, its position in present system of public administration, explains terms like own powers, extended powers and delegated powers. Second chapter of the work introduces valid legal framework about territorial self-government funding and each particular type of municipal government financing as well. It contains analysis of revenues and expenditures of municipalities and regions in last ten years particulary from 2002 to 2011. It clarifies historical development and gives more information about possible future process of municipal budgets. Third chapter deals with specific fund so called "contribution of execution of state administration". The last fourth part introduces budgetary allocation of municipality taxes and revenues - all according to valid legislation. It includes various suggestions of legal amendments of the budgetary allocation of taxes and their positive and negative effects as well.
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Social Media as a New Instrument to Influence Brand Value
Sizikova, Evelina ; Král, Petr (advisor) ; Jurek, Martin (referee)
With the rising power of Internet and especially social media which includes different communities, blogs, portals(1) , etc., nowadays brand value, - its creation and control, is not in the hands of the companies anymore, but is shifted to the consumers. One aim of this paper is to investigate and try to prove the existence of social media influence on brand value. Another goal is to introduce a different vision of brand value in connection with Internet and the rise of social media's influence on consumer's minds. For the purpose of this research the terms brand value and brand equity would bear equal meanings. My theory, which I would like to introduce, was borrowed from biology and physics, namely from I.P. Pavlov's studies and his conditioned reflex theory(2) and the physics part is based on the dispersion of light theory which was first introduced, as we know, by Isaak Newton(3). I dare to say, that nowadays creation of brand value in consumer minds works the same way. When someone, man or woman, hears a brand name, a picture and a feeling, either positive or negative is immediately formed in the person's mind from personal experience with this brand. If not, then the brand is an unfamiliar one, thus we have to rely on a provided opinion, which was previously usually conveyed to us by family, relatives and close friends while recently, also by our growing virtual community. At the beginning of the thesis, I will present the theoretical background and data on World Wide Web and social media, followed by a concise description of some of the existing brand equity models, afterwards introducing my own vision on significant brand value components, elaborating on this theory with the help of relevant case studies and researches. Brand equity has generally been defined as "a brand's power derived from the goodwill and name recognition that it has earned over time, which translates into higher sales volume and higher profit margins against competing brands"(4). Further on in the second chapter I will bring together more definitions on brand equity/value to be able to propose a modified one, components of which will be discussed thoroughly in the same chapter. The main goal of my Master Thesis is to analyze the existence of a dependency between social media and brand value. A second goal is to assess whether the impact is a positive or a negative one or is a mixture of both.
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Assesment of the Environmental Impact in the Design of Production Machines in Terms of Greenhouse Gas Emissions of Selected
Krbalová, Maria ; Blecha, Petr (advisor)
The presented doctoral thesis is focused on environmental impact assessment of basic engineering materials used in a production machine construction. Ecological profile of the machine itself develops already in the phase of its design. It is not only about the choice of future machine parameters and materials that it is built from, but also about technologies used for its manufacture and operation conditions of the finished machine (consumption of energy and service fluids). The thesis occupies in detail with environmental impact analysis of the production machine design from the viewpoint of material production that mentioned machine consists of. The output from the performed analysis is methodology for evaluating of machine design from the viewpoint of greenhouse gas emissions. Created methodology enables evaluating of machine ecological profile and its possible adjustments even during pre-production stage. In the first part of the thesis the analysis of current legislation in the field of fighting against climate changes, reducing of products energy consumption and increasing of production machines energy efficiency is presented. Also in this part of the thesis description of methods that were used to achieve thesis goals is stated. Furthermore analysis of production machine as a system of structural components that fulfil the certain functions and description of used basic engineering materials are presented. The second part of the thesis is devoted to environmental impact analysis of the production machine design process. There the design process and environmental impact of machine design are described. This is followed by description of production machine life cycle and detailed analysis of undesirable substances emissions emitted during pre-production phases of machine life cycle (i.e. during the raw materials extraction and materials production). From this analysis the particular constituents’ pre-production phases which are sources of undesirable substances emissions (e.g. greenhouse gas emissions) were derived. The thesis also includes analysis of these constituents’ life cycles and description of electric power generation as a basic constituent of any phase of product life cycle. In this part of the thesis calculations of particular fuel type’s amounts that is required to produce 1 MWh of electric power and carbon dioxide amount produced during electric power generation are presented. The third part of the thesis contains created models of manufacturing processes of basic engineering materials and calculations of related emissions of selected greenhouse gases. The practical output from this part of the thesis is methodology that enables environmental impact assessment of machine design from the viewpoint of engineering materials used in its construction.
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Electronic Representation of Line Reflex
Yousifová, Hanen ; Šátek, Václav (referee) ; Kunovský, Jiří (advisor)
It would be difficult to imagine a world without communication systems . In order to optimise guided communication systems , it is necessary to determine or project power and signal losses in the system, since all systems have such losses . To determine these losses and eventually ensure a maximum output, it is necessary to formulate some kind of equation with which to calculate these losses . A mathematical derivation for the telegraph equation in terms of voltage and current for a section of a transmission line will be investigated .
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Comparison of selected classification methods for multivariate data
Stecenková, Marina ; Řezanková, Hana (advisor) ; Berka, Petr (referee)
The aim of this thesis is comparison of selected classification methods which are logistic regression (binary and multinominal), multilayer perceptron and classification trees, CHAID and CRT. The first part is reminiscent of the theoretical basis of these methods and explains the nature of parameters of the models. The next section applies the above classification methods to the six data sets and then compares the outputs of these methods. Particular emphasis is placed on the discriminatory power rating models, which a separate chapter is devoted to. Rating discriminatory power of the model is based on the overall accuracy, F-measure and size of the area under the ROC curve. The benefit of this work is not only a comparison of selected classification methods based on statistical models evaluating discriminatory power, but also an overview of the strengths and weaknesses of each method.
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