This master's thesis deals with separation of metallurgical materials focused on cutting and other general methods of material separation. The aim of this thesis is to focus on cutting of rolled material by saw, specification of technological aspects of cutting of rolled materials, techno-economic analysis of the problem

En este trabajo, en primer lugar, se presenta una nueva técnica desarrollada en nuestro laboratorio para el estudio electroquímico de las capas catalíticas de las pilas de combustible en células de tres electrodos, centrándonos en el proceso de electroxidación de ácido fórmico como reacción de test. Gracias a esta técnica se han estudiado parámetros de construcción como % en peso del metal, relación Nafion / sólidos totales y recubrimiento catalítico comprobando como la adsorción irreversible de adátomos de Bi sobre Pt soportado sobre Vulcan XC-72 favorece este proceso y como puede caracterizarse la capa catalítica de una pila de combustible de ácido fórmico (DFAFC) de forma integral utilizando estudios de sistemas nanoparticulados de Pt-Pd soportados sobre Vulcan XC-72 en el seno de ésta. En segundo lugar se ha introducido el concepto de PEMER (Polymer Electrolyte Membrane Electrochemical Reactor). De esta forma, una configuración electródica propia de las pilas de combustible se utiliza en electrosíntesis orgánica. Como reacciones test se han testeado la formación de 1-feniletanol como producto mayoritario por hidrogenación electrocatalítica de la acetofenona sobre nanopartículas de Pd soportadas sobre Vulcan XC-72 como electrocatalizador y, utilizando Pb (catalizador no noble) soportado sobre Vulcan XC-72, se ha estudiado la ruptura del puente disulfuro de L-cistina y N,N-diacetil-L-cistina (NNDAC) para obtener L-cisteína y N-acetil- L-cisteína (NAC). En ambas reacciones, hidrogenación y ruptura del puente disulfuro, se han analizado tanto parámetros constructivos de la capa catalítica como parámetros de proceso tanto a escala laboratorio con el uso de un reactor comercial de 25 cm² como a escala pre-piloto con la construcción de un reactor de 100 cm².

El constante desarrollo industrial y tecnológico ha establecido un escenario dónde, la demanda energética, en especial la eléctrica, se incrementa rápidamente. En este sentido la creciente explotación de los combustibles fósiles, ha logrado en las últimas décadas una fuerte reducción de sus yacimientos y el incremento de la contaminación ambiental. Tomando conciencia de estos problemas surgió la necesidad de diversificar las fuentes primarias de energía, introduciendo fuentes alternativas sustentables y no contaminantes. Entre éstas, las de origen renovable presentan algunas características que las hacen atractivas: complementariedad, libre disponibilidad y capacidad de generación inagotable. En este contexto, como una alternativa a los tradicionales vectores energéticos basados en combustibles fósiles, aparece la posibilidad de emplear un nuevo vector: el hidrógeno, un recurso no contaminante y eficiente. Además, empleado conjuntamente con Pilas de Combustible, puede producir electricidad y calor, con agua pura como único residuo. En base a lo expuesto, en esta tesis se aborda el desarrollo de un Sistema Híbrido de Generación de Energía Eléctrica versátil, basado en una Pila de Combustible PEM y Supercapacitores. De las tecnologías desarrolladas, las Pilas de Combustible tipo PEM, han demostrado un excelente desempeño como fuentes de energía en diversas aplicaciones, gracias a su reducido tamaño, robustez y baja temperatura de operación. Los Supercapacitores, presentan una alta densidad de potencia y frente a otras tecnologías tradicionales actuales son mas compactos, robustos y poseen mayor vida útil. De esta manera, esta combinación permite obtener un sistema de generación de alta densidad energética (gracias al funcionamiento continuo de las primeras) y muy buen desempeño dinámico. El sistema desarrollado tiene por objetivo ser utilizado como fuente de alimentación flexible en múltiples aplicaciones o bien, como una potente herramienta para el desarrollo de avanzadas estrategias de gestión de energía, en ámbito de laboratorio.

El avance tecnológico más importante de las próximas décadas pasa por el uso del hidrógeno como combustible, sustituyendo el consumo masivo de los combustibles fósiles. De esta manera, utilizando tecnologías basadas en pilas de combustible, conseguiremos sistemas energéticos más eficientes que los actuales y, además respetuosos, con el medio ambiente. / The most important technological development in the coming decades will be the use of hydrogen as an alternative to the widely used fossil fuels. By the use of fuel cell based technologies, it will be feasible to produce energy systems that will be more efficient than the current ones and that will also be environmentally friendly.

This thesis deals with the proposal of production technologies for a band saw clamp plate. Introduction of thesis is focused on problematics about selected component. In the next section, there are described technologies, which were used in the thesis. Practical part is about proposals of conventional and unconventional production methods. Methods are evaluated in the conclusion of thesis.

This diploma thesis titled Proposal for Modernization of the Bojkovice Sawmill deals with the analysis of the Bojkovice sawmill operation and with the proposal for the increase of production capacity. The thesis summarizes basic information about the company DATO-FOREST s.r.o., i.e. the Bojkovice sawmill. It deals with the present state of the sawmill operation, with production downtime tracking, as well as with the analysis of these problems. The practical part offers three options of these problems, proposals for the increase of production capacity, drawing documentation, and calculation of payback period. Individual solutions were compared from both economic and production effectivity point of view. One of these three options was chosen and processed in detail.

<p><i>Francisella tularensis</i> is a Gram-negative intracellular pathogen causing the zoonotic disease tularemia. <i>F. tularensis</i> can be found almost all over the world and has been recovered from several animal species, even though the natural reservoir of the bacterium and parts of its life cycle are still unknown. Humans usually get infected after handling infected animals or from bites of blood-feeding arthropod vectors. There are four subspecies of <i>F. tularensis</i>: the highly virulent <i>tularensis</i> (Type A) that causes a very aggressive form of the disease, with mortality as high as 60% if untreated, the moderately virulent <i>holarctica</i> (Type B) and <i>mediasiatica</i>, and the essentially avirulent subspecies <i>F. novicida</i>. So far, our knowledge of the molecular mechanisms that would explain these differences in virulence among the subspecies is poor. However, recent developments of genetic tools and access to genomic sequences have laid the ground for progress in this research field. Analysis of genome sequences have identified several regions that differ between <i>F. tularensis</i> subspecies. One of these regions, RD19, encodes proteins postulated to be involved in assembly of type IV pili (Tfp), organelles that have been implicated in processes like twitching motility, biofilm formation and cell-to-cell communication in pathogenic bacteria. While there have been reports of pili-like structures on the surface of <i>F. tularensis</i>, these have not been linked to the Tfp encoding gene clusters until now. Herein, I present evidence that the <i>Francisella</i> pilin, PilA, can complement pilin-like characteristics and promote assembly of fibers in a heterologous system in <i>Neisseria gonorrhoeae. pilA</i> was demonstrated to be required for full virulence of both type A and type B strains in mice when infected via peripheral routes. A second region, RD18, encoding a protein unique to <i>F. tularensis</i> and without any known function, was verified to be essential for virulence in a type A strain. Interestingly, the non-licensed live vaccine strain, LVS (Type B), lacks both RD18 and RD19 (<i>pilA</i>) due to deletion events mediated by flanking direct repeats. The loss of RD18 and RD19 is responsible for the attenuation of LVS, since re-introducing them <i>in cis</i> could restore the virulence to a level similar to a virulent type B strain. Significantly, these deletion events are irreversible, preventing LVS to revert to a more virulent form. Therefore, this important finding could facilitate the licensing of LVS as a vaccine against tularemia.</p>

Francisella tularensis is a Gram-negative intracellular pathogen causing the zoonotic disease tularemia. F. tularensis can be found almost all over the world and has been recovered from several animal species, even though the natural reservoir of the bacterium and parts of its life cycle are still unknown. Humans usually get infected after handling infected animals or from bites of blood-feeding arthropod vectors. There are four subspecies of F. tularensis: the highly virulent tularensis (Type A) that causes a very aggressive form of the disease, with mortality as high as 60% if untreated, the moderately virulent holarctica (Type B) and mediasiatica, and the essentially avirulent subspecies F. novicida. So far, our knowledge of the molecular mechanisms that would explain these differences in virulence among the subspecies is poor. However, recent developments of genetic tools and access to genomic sequences have laid the ground for progress in this research field. Analysis of genome sequences have identified several regions that differ between F. tularensis subspecies. One of these regions, RD19, encodes proteins postulated to be involved in assembly of type IV pili (Tfp), organelles that have been implicated in processes like twitching motility, biofilm formation and cell-to-cell communication in pathogenic bacteria. While there have been reports of pili-like structures on the surface of F. tularensis, these have not been linked to the Tfp encoding gene clusters until now. Herein, I present evidence that the Francisella pilin, PilA, can complement pilin-like characteristics and promote assembly of fibers in a heterologous system in Neisseria gonorrhoeae. pilA was demonstrated to be required for full virulence of both type A and type B strains in mice when infected via peripheral routes. A second region, RD18, encoding a protein unique to F. tularensis and without any known function, was verified to be essential for virulence in a type A strain. Interestingly, the non-licensed live vaccine strain, LVS (Type B), lacks both RD18 and RD19 (pilA) due to deletion events mediated by flanking direct repeats. The loss of RD18 and RD19 is responsible for the attenuation of LVS, since re-introducing them in cis could restore the virulence to a level similar to a virulent type B strain. Significantly, these deletion events are irreversible, preventing LVS to revert to a more virulent form. Therefore, this important finding could facilitate the licensing of LVS as a vaccine against tularemia.

The intention of this thesis is to occupy with the influence of a chain to a vibration level of a chainsaw. The first part of this work occupies with a theoretical approach to a vibration problem of a chainsaw, the causes of the vibration and their results, especially from the literary and internet sources. The main concern in the second part is the practical verification of the influence of the construction of chain saw chain change for the vibration of a chain saw. The vibration measurement was made by the cutting different kinds of wooden planks with three different chainsaw chains (POWERsharp, half-chiselled and chiseled profile of woodworking plane tooth). In the last part of this work I evaluate and make a remark of registered values tested chainsaw chains. It was made during the practical exam in the workshops of the Institute of Forestry and Wood Technology in Brno under the expert's supervision.

The master thesis deals with the design and manufacture of tabbed joint in the profile with a square cross section using laser cutting. They examine their suitability and impact on the following MAG welding operation in terms of efficiency and accuracy. The theoretical part provides basic information about lasers used in industry and laser cutting methods. There is also a section dedicated to laser apparatus for tube cutting along with problematic about the laser cutting profiles. The experimental part describes the procedure of designing tabbed joint, making samples and measuring them. In the end, the individual samples are compared in terms of angular deflection after welding. The thesis also contains a technical-economic evaluation, where the costs of individual operations are quantified.