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Design of audio power amplifier with Bluetooth connectivity
Bartoň, Jan ; Šotner, Roman (referee) ; Brančík, Lubomír (advisor)
This bachelor‘s thesis deals with the task of designing an audio amplifier, operating in class D, with a nominal output power of 2 x 80 W with Bluetooth connectivity, supplemented by an equalizer and a state display. A power supply and a user interface are designed as well. At first, research regarding audio amplifiers is made, followed by a more thorough description of class D operating principles. Afterwards the actual synthesis of the desired amplifier is presented, followed by the power supply design procedure. The correctness of the synthesis is later verified by simulations in PSpice and LTSpice. Theoretical design is then practically built, and its parameters are confronted with expected values by measurements.
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Prediction of Protein Stability upon Mutations Using Evolution Strategy
Pavlík, David ; Martínek, Tomáš (referee) ; Bendl, Jaroslav (advisor)
This master's thesis deals with the matter of predicting the effects of aminoacid substitutions on protein stability. The main aim is to design meta-classifier that combines the results of the selected prediction tools. An evolution strategy was used to find the best weights for each of the selected tools with the aim of achieving better prediction performance compared to that achieved by using these tools separately. Five different and obtainable prediction tools were selected and their prediction outputs were weighted. Two different approaches of evolution strategy are investigated and compared: evolution strategy with the 1/5-rule and evolution strategy with the type 2 of control parameters self-adaptation. Two independent datasets of mutations were created for training and evaluating the performance of designed meta-classifier. The performed experiments and obtained results suggest that the evolution strategy could be considered as a~beneficial approach for prediction of protein stability changes. However, the special attention must be paid to careful selection of tools for integration and compilation of training and testing datasets.
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VD Vlachovice - concrete gravity dam
Juriga, Jan ; Šulc, Jan (referee) ; Zachoval, Zbyněk (advisor)
As a part of this bachelor thesis an alternative design of the concrete gravity dam VD Vlachovice was made, to the already design of the earth-fill dam. The design of the outlet works, intake and spillway were also carried out as a part of the study. The introduction of the thesis includes a description of the site and an evaluation of local conditions. The next part deals with the stability of the dam and the load-bearing capacity of the subsoil. Furthermore, the design of the outlet works, intake and spillway were made. A part of the thesis also deals with the transformation of flood by the water reservoir. Finally, drawings and simplified 3D model of the dam were created. The documents necessary for the creation of the work were provided by company AQUATIS a.s. with the permission of Povodí Morava, s.p.
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Stability of humic complexes
Vlašicová, Silvie ; Smilek, Jiří (referee) ; Klučáková, Martina (advisor)
This bachelor thesis is focused on humic acids as an active ingredient of organic soil substance and their interaction with the selected drug, Ibuprofen. The aim of this work was to optimize the methods of drug determination in solutions containing humic acids. Subsequently, adsorption experiments were performer to provide information about the adsorption efficiency depending on the concentration of Ibuprofen. Desorption experiments were then used to determine the stability of humic substance complexes with Ibuprofen, or, more precisely, the proportion of the mobile and bound Ibuprofen fraction in the prepared complexes.
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Mathematical modeling of population problems in biology
Čampulová, Martina ; Opluštil, Zdeněk (referee) ; Čermák, Jan (advisor)
This bachelor´s thesis deals with the modeling of population problems in biology. The aim of this thesis is to mention some basic models describing dynamics of the evolution of one or two populations. Models mentioned in this thesis are described by first-order ordinary differential equations. Exploring the evolution of the population brings the main question - searching for singular points (and verifying their stability) of differential equations describing the evolution of the population. Therefore the thesis also deals with these problems.
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System analysis of braking truck - trailer combination
Haring, Andrej ; Kubjatko,, Tibor (referee) ; Řehák,, Miloslav (referee) ; Semela, Marek (advisor)
The dissertation deals with the issue of braking of articulated vehicles, especially articulated vehicles consisting of a tractor and a semi-trailer. This configuration was chosen with regard to the number of accidents and their consequences, and often also does not suit the technical condition of the tractor and semi-trailer, which is closely related to the safety of operation of these combinations. In the case of road accidents, the consequences are often very serious, whether it is personal injury or material damage. Investigating these accidents is a relatively demanding process, requiring a high degree of expertise as well as the necessary technical equipment. In contrast to these requirements, the availability of sources from which the necessary information can be drawn is relatively low. The available resources are mostly in a foreign language and are usually solutions to partial problems, not systemically comprehensive literature. Therefore, it is possible to say a "constant demand" for the available professional literature dealing with issues related to the solution of traffic accidents not only of combinations of vehicles, but of commercial vehicles as a whole. From the point of view of the importance, or topicality of needs arising from expert practice, the dissertation is thematically focused on braking of combinations of vehicles. There are several key reasons to focus on articulated vehicles. First of all, this is due to the specific character of the vehicle itself, which consists of two communication-linked brake systems. Other reasons are that the information contained in the dissertation, whether it is descriptive information, assessment of the technical condition of the systems, or the measurement results themselves, can be partially or even fully used for stand-alone towing vehicles or trailers. However, not all problems related to this issue can be solved within the dissertation. Therefore, in the dissertation, significant influences are selected, the solution of which, given the frequency and severity, the author considers essential. From the title of the dissertation it follows that this is a system analysis of the braking of combinations of vehicles. The system concept of solving a problem situation and selected problems are a guarantee that really essential parameters are selected within the content possibilities and scope of the dissertation and the system approach to their solution allows a "general" application in solving similar problems. The aim of the dissertation is a system analysis of the influence of selected parameters on the overall braking effect and stability of commercial vehicle combinations, analysis of input parameters on the decision logic of electronic brake system control unit, where procedures but also conclusions can be applied in similar cases with similar input parameters and decision criteria. Another partial goal is to develop a framework methodology for determining the technical condition of individual components of brake systems of commercial vehicles, which will be possible to apply especially in trucks, where electronically controlled systems are installed. Here, too, a systemic concept is applied, which will enable a wider use of this methodology.
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Preparation and application of nanoparticles and nanofibres with natural UV filters
Plachá, Monika ; Skoumalová, Petra (referee) ; Márová, Ivana (advisor)
The presented diploma thesis is focused on preparation of nanoparticles and nanofibres with natural UV filters. Liposomes with encapsulated aqueous, ethanol and lipid extracts were prepared. Nanofibers from PHB containing lipid extract were prepared too. As a part of this work, an overview of natural sources with potential effects as UV filters were introduced. Moreover, nanoparticles and nanofibers and methods of their characterization were described. Size, polydisperse index and colloid stability of prepared nanoparticles were characterized via DLS. In experimental part aqueous, ethanol and lipid extracts were prepared from roasted coffee, green coffee and cascara. These extracts were spectrophotometrically characterized for the content of polyphenols, flavonoids, antioxidant activity, tannins and their SPF. Liposomes and liposomes containing PHB with these extracts were prepared and the encapsulation effectivity, short–term and long–term stability as well as SPF of nanoparticles were determined. Nanofibers from PHB containing lipid extracts were prepared via electrospinning and forcespinning methods. Prepared nanofibers were examined via FTIR–ATR. Antioxidant activity, short–term and long–term stability were determined spectrophotometrically. From selected nanoparticles, emulsions and gels were prepared and their SPF was also determined. Three types of emulsions with the best SPF were selected and tested on volunteers. Sedimentation stability of emulsions was tested by analytical centrifuge. Finally, cytotoxicity of selected nanoparticles and nanofibers was tested via MTT assay using human keratinocytes.
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Stability problems study of framed structures
Piják, Jiří ; Vlk, Zbyněk (referee) ; Zídek, Rostislav (advisor)
In the first chapter the problem of ideal member, member with initial curvature and meaning of Euler’s critical force is regarded. Parameters of stability, mainly calculation of critical loading and buckling lengths, are studied in the second part. The same part contains comparison of results of computational programs and mechanical approach. Next attention is paid to imperfections, to possibilities of determination and comparison of results on a simple member. Comparison of possible judgements of buckling on a simple beam and on frames according to ČSN EN 1993-1-1 is performed on the final part.
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Analysis of Logistic Maps
Adeleke, Joshua Owolabi ; Šremr, Jiří (referee) ; Řehák, Pavel (advisor)
Logistická mapa souvisí s diskrétní logistickou rovnicí. Na rozdíl od svého kontinuálního protějšku vykazuje logistická diferenční rovnice velmi komplikovanou dynamiku včetně chaotiky chování. Tato práce tak zkoumala kvalitativní chování logistické mapy podle pomocí některých matematických nástrojů. Tato dynamika byla studována systematicky, a to tak, aby její povaha byla čistá forma až do bodu, kdy bylo komplikované se s ní vypořádat, byly pečlivě studovány. dále pojem konjugace byl zaměstnán v okamžiku, kdy jeho analytický výpočet představoval být komplikovaný, s čímž byly dále odhaleny jeho vlastnosti. Byly učiněny pozoruhodné závěry, mezi nimiž je popis chaotického chování logistická mapa, jak ji odhaluje její spojení se stanovou mapou. V průběhu této studie tedy existuje další nástroj pro vyšetřování chaotického chování byla poznamenána logistická mapa, která je symbolickou dynamikou, se kterou se bude v budoucnu studovat logistická mapa může zabrat.
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