Rok 2016
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- ItemVliv difúze na PECVD funkčních vrstev(Technická Univerzita v Liberci, 2015) Volfová, LenkaThis thesis deals with thin layers deposition on porous substrates by the PECVD method. Active particles diffusion is one of the most significant factors influencing the homogeneity of thin layers created on spatially complicated substrates during plasmatic process. One of the main purposes of this thesis was the research of the particles' penetration into the spaces shielded from the direct exposure to the plasma. The measurement methodology was designed and a model substrate was built to allow the measurements of fluidity of thin films within different shade areas. Another purpose of the test was study of the influence of the precursor molecules' size on the diffusion during the process of thin film deposition. Therefore two precursors with significantly different molecular weights acetylene and TTIP were used for the layer formation. The demonstrated effect was supported by the results of a mathematical model, based on the parameters of the process. Its very good conformity with the measured results indicates the possibility of prediction of behavior during PECVD process. Good compatibility with computer simulation has been demonstrated in the case of formation of a layer on the textile fabric of cotton, basalt and glass fibers. The layers formed on technical fabrics from basalt and glass fibers proved the photocatalytic activity. This confirmed the prospects of textile substrates for coating by TiO2 layeres due to the large surface area of textile materials.
- ItemZážehové motory při provozu na biobutanolová paliva(Technická Univerzita v Liberci, 2016) Pechout, Martin; Laurin, Josef
- ItemVliv parametrů předtvarování fólie na kvalitu tvarově složitých dílů u technologie IMD(Technická Univerzita v Liberci, 2016) Petera, PavelPresented dissertation is aimed on new technology IMD with pre-forming (transfer type), which allows highly productive decoration of injection-molded part directly in injection mold. IMD with pre-forming is an alternative to commonly used IML but when compared together IMD with pre-forming has a clear advantage in strong cost reduction according to IML. Additionally complexity of feasible shape is much higher in the case of IMD with pre-forming compared to standard IMD. This thesis is focused on evaluation of pre-forming parameters influence on foil deformation during IMD process but as well parts quality characterised by fault presence. Experiment has been done on large and complex IMD part by using hi gloss IMD foil and PC/ABS resin. For the purpose of deformation study was developed and verified new process which included a new way of geometric pattern printing on IMD foil which allowed to evaluate also deformation which happened by melt flow during injection molding process. For evaluation the influence of pre-forming parameters on parts quality was presented own approach of faults presence evaluation. The topic has been solved under the terms of solution of research program SGS 21122.
- ItemSystém pohonu maloprůměrového pletacího stroje(Technická Univerzita v Liberci, 2016) Skřivánek, JosefThe dissertation deals with the issue of the drive system of the small diameter knitting machines (hereinafter knitting machines) with regard to the targeted use of the needle cylinder, the dial a the cutting disc in the process of knitting. The main aim is to design a new drive system of knitting machines, based on an analysis of the current state referring to the state of current solutions of drive systems. The introduction is focused on the processing and presentation of the current state of the field and issues connected to this topic, there are presented and compared the different concepts of used or invented the drive systems here. In the response to the introductory part is designed and presented a new alternative of drive system that takes into account inclusion of selected working members i.e. the needle cylinder, the dial and the cutting disc. New drive system is compared to the current solution and is divided into three individually controlled parts where existing solutions with a single central drive is replaced by three controlled drives, which are electronically coupled. For a description and simulation of the drive systems are constructed mathematical models of the current and the new drive system, which includes a better draft stroke. The output of simulations are s-v-a diagrams and diagrams of active electrical current, pointing to the contribution of the new drive system. Based on the structure of the new drive system is designed and manufactured test equipment used to verify the functionality and reliability, where the main emphasis is on compliance with the required maximum positional deviation between the needle cylinder and the dial in a knitting mode called slinging. Measurement at this test equipment demonstrates the practical applicability of the proposed drive system and the estimated energy savings. In the final part was developed, manufactured and tested functional model of the individual drive system of the cutting disc, in which there is the possibility to implement into the existing machine concept. The work contributes to the development of issues of drive and drive systems of small diameter knitting machines, design of the new drive system with real application in this field.
- ItemAnalýza teplot v ozubení pastorku stálého převodu(Technická Univerzita v Liberci, 2016) Mazač, MartinThe thesis focuses on the measurement of pinion gear teeth temperature in an automobile gearbox. A test stand for gearbox loading and a gear teeth temperature measurement system were designed, constructed, and used for experimental investigations. The temperature inside multiple teeth of a rotating pinion gear is measured by embedded thermistors, and an optical method is used to transfer the signal from the shaft. Special software was written to facilitate operation, calibration and data processing. The setup was validated on a series of runs spanning different gears, rotating speeds, and power levels, the results of which are described and summarized.
- ItemVliv předehřevu zálisků na kvalitu hybridního spoje(Technická Univerzita v Liberci, 2016) Paclt, RomanThe dissertation thesis deals with problematic of insert technologies. It investigates temperature and pressure relation during over-molding of metal component with analitic way, numerical way with usage of computer simulations and by measurement. In this way are confronted theoretical preconditions to the real results of measurement. Next point of this thesis is analysing of influence of metal inserts temperature in combination with another factor which is a choice of plastic material on connection between metal and plastic. A special focus is aimed on the stiffness of connection and supermolecular structure of polymer. Polarization microscopy for observing of microtom cuts and method DSC is used for this proposal. The result is a description of relation of cristalinity of polymer in place of connection and away from this place, stiffness of the connection and various properties on technological parameters of injection moulding process.
- ItemNumerické simulační výpočty ve slévárenských procesech a materiálech(Technická Univerzita v Liberci, 2016) Horáček, Josef; Nová, Iva
- ItemAnalýza proudění u dvoudobých spalovacích motorů(Technická Univerzita v Liberci, 2016) Poucha, Vít; Moc, Lubomír
- ItemCharakteristika materiálu a rozvoj deformace hořčíkových plechů v oblasti mezních stavů(Technická Univerzita v Liberci, 2016) Bělková, Monika; Solfronk, Pavel
- ItemStrategie rozvrhování pracovníků na výrobní linky(Technická Univerzita v Liberci, 2016) Vavruška, Jan; Manlig, František
- ItemModelování globálních mechanických vlastností na základě experimentálního stanovení vlastností lokálních(Technická Univerzita v Liberci, 2016) Burik, Peter; Pešek, Ladislav
- ItemVýzkum technologie přípravy a zpracování kompozitů s PLA matricí a vlákny rostlinného původu(Technická Univerzita v Liberci, 2016) Habr, JiříThesis deals with the phenomenon of production and processing biocomposites having absolutely plant origin. The aim of this thesis is research of the technologies for preparation and processing biocomposites which are on the basis of the fully biodegradable PLA matrix with chosen plant fibers and to carry out measurements of their mechanical properties, melt mass-flow rate and evaluation of their processability. Subsequently (on the basis of such results) there is necessity to perform selection of the proper fiber type for production biocomposites without necessary to use any chemical additives for improving interphase adhesion on the matrix-fiber boundary. As a partial aim of this theses there is effort to test possibilities for utilization low-temperature plasma atmospheric dielectric barrier discharge (DBD) as well as fibers surface physical treatments to improve interphase adhesion. This treatment is maximally environmentally friendly treatment which perfectly matches with the philosophy of the fully biocomposite materials. As an integral part of this thesis there is also mapping of the technological complications accompanying compounding and injection of biocomposites having PLA matrix and plant fibers. Moreover, there i salso effort to determinate supposed causes and to propose possibilities for their elimination while keeping maximal quality of the biocomposite.
- ItemStruktura a vysokoteplotní mechanické vlastnosti aluminidů železa s karbidotvornými příměsemi niobem a zirkoniem(Technická Univerzita v Liberci, 2016) Švec, MartinThe dissertation deals with a study of structure and high-temperature mechanical properties of Fe3Al-type iron aluminides doped by carbide forming elements (Zr, Nb) and carbon. The influence of mutual Zr/C (event. Nb/C) ratio on type and amount of emerging secondary phases (Laves phase and carbides) were studied. The influence, which have these phases on high-temperature mechanical properties, was studied. It was also verified the influence of heat treatment and heat-mechanical treatment of alloys on phase structure and high-temperature mechanical properties. The structure of investigated materials was studied by light optical microscopy and scanning electron microscopy. The phase composition was verified by EDX, RTG diffraction and EBSD. Yield strength for individual types of alloys was measured in compression in temperature range 600 800°C. For alloys with niobium addition there was also measured (except yield strength in compression) yield strength in tension in the same temperature range, creep resistance and coefficient of thermal expansion in temperature range 400 1200°C.
- ItemZajištění kvality odporových bodových svarů na základě analýzy časových průběhů vybraných veličin svařovacího procesu(Technická Univerzita v Liberci, 2016) Pacák, Jiří; Neumann, Heinz
- ItemTermodynamické procesy při akumulaci tepla ve vodních zásobnících(Technická Univerzita v Liberci, 2016) Švarc, Petr; Dvořák, VáclavTato práce shrnuje výsledky studia termodynamických procesů objevujících se při nabíjení a vybíjení vodních akumulačních zásobníků tepla. Obsahuje popis a posouzení různých způsobů ukládání tepelné energie a procesů vyskytujících se při přívodu a odvodu tepla z akumulačních zásobníků. Vyšetřování a posuzování dějů doprovázejících provoz zařízení bylo provedeno pomocí teoretických, numerických, ale i experimentálních metod. K teoretické studii byly použity základní zákony přenosu tepla a hmoty a znalosti termodynamiky. Byla aplikována teorie podobnosti pro studium dějů, ke kterým dochází při nabíjení a vybíjení vodních akumulačních zásobníků tepla, a pro studium přestupu tepla z horizontálně uloženého válce ve vodním prostředí. Pro numerické vyšetřování byly použity shodné fyzikální modely, byly definovány materiálové vlastnosti, okrajové a počáteční podmínky analogické se současně prováděnými experimenty. Získané výsledky byly porovnávány s výsledky ostatních autorů zabývajících se obdobnou tématikou. Pomocí provedených rozborů byly zkoumané děje identifikovány a kvantitativně a kvalitativně zhodnoceny.$aThis work summarizes results of studies of thermodynamic processes, which occur during charging and discharging of the water thermal energy storages. It contains description and assessment of different ways to store thermal energy, and processes occurring during charging and discharging of storage tanks. Investigation and assessment of processes accompanying the operation were performed by using theoretical, numerical, and experimental methods. For the theoretical study were used basic laws of the heat and mass transfer, and knowledge of thermodynamics. The dimensional analysis was used for study of the processes which occur during charging and discharging of the water thermal energy storages and during heat transfer from surface of a horizontal cylinder in the water. Identical physical models of a fluid flow were used for numerical investigation of different material properties, which were defined, initial boundary conditions, and analogous conditions were implemented simultaneously to the experiments. The results obtained by the investigations were compared to the results of other authors dealing with similar issues. Consequently, all the studied processes were identified, and quantitatively and qualitatively evaluated on the bases of performed analyses.
- ItemMetodika pro experimentální dvojrozměrnou analýzu samobuzených kmitů(Technická Univerzita v Liberci, 2016) Petříková, MarkétaThis doctoral thesis is focused on the development of the measurement methodology for the detection of self-excited oscillations. Self-excited oscillations may be generated by the flow around bodies and by the flow during the cavity filling. In the framework of this work new measurement devices were developed. The methodology was verified on test cases repre-sented by the flow around various bodies and by the process of cavity filling with liquid. The hydrodynamic table was applied to identify the self-excited transient oscillations. Aluminum particles on the water surface were used for the flow visualization. The water surface and pulsation frequencies were measured by developed sensors. Experimental measurements were compared with numerical simulations. The obtained results were used in the develop-ment and verification of the experiment methodology.
- ItemVliv materiálů na velikost kritických deformací(Technická Univerzita v Liberci, 2016) Jíra, Tomáš; Solfronk, Pavel
- ItemVývoj zařízení ke stanovení odvozeného cetanového čísla paliv(Technická Univerzita v Liberci, 2016) Holubec, Radek; Laurin, JosefPráce se zabývá vývojem, stavbou a kalibrací zkušebního zařízení ke stanovení odvozeného cetanového čísla paliv pro vznětové motory. Ke stanovení OCČ se využívá dobré korelace průtahu vznícení a vznětlivosti paliva vstříknutého do ohřátého stlačeného vzduchu. Na rozdíl od obdobných zařízení založených na měření pouze jedné veličiny (průtahu vznícení) využívá zařízení vyvinuté na KVM za účelem zpřesnění stanovení OCČ hodnotu teploty náplně a gradient teploty stěny komory. Další zdokonalení spočívá v použití moderního palivového systému (common rail), který umožňuje vytvořit podmínky vstřiku podobné podmínkám u moderních vznětových motorů.$aThe disertation focuses on a developement, construction and calibration of the apparatus for the determination of derived cetane number of fuels for diesel engines. The determination is based on a good correlation between ignition delay and self ignition of fuel injected into a combustion chamber filled with compressed air heated to suitable pre-determined temperature. In contrast to the comparable devices which use for the determination DCN only one variable (ignition delay) uses the apparatus developed at the Department of Vehicles and Engines at the Technical University of Liberec in order to more precise the determination other variables like the charge temperature and the temperature gradient of the chambre wall. The fuel is injected using a Common Rail injection system which is used in the modern diesel engines.
- ItemVliv parametrů předtvarování fólie na kvalitu tvarově složitých dílů u technologie IMD(Technická Univerzita v Liberci, ) Petera, Pavel
- ItemVýzkum vlivu vstřikovacích parametrů (teplota taveniny, dotlak, rychlost) na lokální smrštění výstřiku(Technická Univerzita v Liberci, ) Záboj, Robert