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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.
221

Evaluation of the level of the organic brewing industry in selected countries of the European union

Fidrová, Veronika January 2014 (has links)
This diploma thesis deals with the topic "Evaluation of the Level of Organic Brewing Industry in Selected Countries of the European Union". It is describing the current situation of organic hop growing industry and organic brewing industry in two selected countries that are the Czech Republic and the Federal Republic of Germany with the help of two analyses of the external environment (PESTEL analysis and the Porter's Diamond Model). On the basis of these two analyses the evaluation and comparison of both countries are done. And finally, as it is the main objective of this diploma thesis there are recommendations for Czech organic hop growers how to enter the German market and which export strategy is the most suitable for them.
222

Antibakteriální a antiadhezivní účinky uhlíkových nanomateriálů / Antibacterial and antiadhesive properties of carbon nanomaterials

Budil, Jakub January 2018 (has links)
Increasing interest in industrial and medical applications of carbon nanomaterial leads to the need to examine its interactions with living systems. Nanocrystalline diamond (NCD) films possess high mechanical and chemical stability which, together with its biocompatibility with human cells, enables applications in human body. Some of carbon nanoparticles possess strong antibacterial activity. In this work the effects of NCD with hydrogen, oxygen and fluorine termination deposited on glass and silicone on adhesion of gram-negative bacteria Escherichia coli K-12 in mineral medium is described and the impact of cultivation medium on effects of NCD films is compared. Prior the growth of the E. coli biofilm on NCD films, the method for quantification of biofilm using crystal violet staining and the method for biofilm cultivation in mineral medium were optimised. The properties of NCD film are independent on the base substrate. Hydrogen and fluorine terminated NCD films show antiadhesive properties only in mineral medium but not in complex medium. This is explained by formation of a conditioning film on the surface of the NCD film during cultivation in complex medium. On the other hand, O-NCD film supports bacterial adhesion in both cultivation media. Second part of this thesis is dedicated to carbon...
223

Élaboration de carbures cémentés à gradient de propriétés par procédé d’imbibition réactive : Application aux inserts WC-Co et aux taillants en diamant polycristallin pour le forage pétrolier en conditions sévères / Functionally graded cemented carbides elaboration by reactive imbibition process : Application for WC-Co inserts and PDC cutters for oil drilling in harsh conditions

Ther, Olivier 16 December 2014 (has links)
Dans l'industrie du forage pétrolier, les conditions de travail de plus en plus sévères requièrent sans cesse de nouveaux outils plus résistants à l'usure abrasive et à l'impact. Afin de répondre à ce défi, les travaux présentés ici, ont pour but l'élaboration de matériaux en carbure cémenté à gradient de composition par le procédé d'imbibition réactive. Ce procédé peut être décomposé en deux procédés de gradation, à savoir : l'imbibition et le revêtement réactif. L'imbibition a pour rôle d'enrichir graduellement, en phase liante, le coeur d'une pièce en carbure cémenté dense et repose sur le principe de migration de phase liquide dans un corps solide-liquide. Le revêtement réactif est un procédé qui s'applique également sur un carbure cémenté dense sur lequel est déposé un revêtement de nitrure de bore. Après avoir atteint le liquidus de la phase liante du carbure cémenté, une précipitation de borures ternaires prend place à la surface du matériau et s'étend graduellement sur des distances millimétriques. Dans le cas de pièces industrielles (inserts tricône et supports de taillants PDC (Polycrystalline Diamond Compact)), le traitement d'imbibition réactive permet de générer des gradients de dureté pouvant atteindre 450 HV sur 25 mm. L'élaboration de tels gradients a nécessité une meilleure compréhension des cinétiques ainsi que des phénomènes mis en jeu durant l'imbibition et le revêtement réactif. Dans le cas des taillants PDC, l'influence des paramètres du procédé HPHT de synthèse de la plaquette diamantée, sur le gradient de composition présent dans le support WC-Co après imbibition réactive, a été étudiée. Ces travaux se sont également intéressés à l'effet de ces gradients de composition sur les propriétés des plaquettes diamantées ainsi obtenues. A la suite d'essais mécaniques, les inserts WC-Co et taillants PDC gradués montrent une augmentation significative de leur résistance à l'abrasion (de 30 à 100%) et de leur tenue à l'impact (de 20 à 40%). / In oil drilling industry, harsher working conditions require ever new and more abrasive wear and impact resistant tools. To meet this challenge, the work presented here, is to develop graded cemented carbide materials by reactive imbibition process. This method can be divided into two gradation processes, namely, reactive coating and imbibition. Imbibition gradually enriches the core of dense cemented carbide with binder phase and is based on the principle of liquid phase migration in a solid-liquid body. Reactive coating also takes place in dense cemented carbide on which a boron nitride coating is deposited. After reaction with the WC-Co liquid binder, some ternary boride precipitations take place from surface to several millimeters deep. For industrial parts (inserts for roller cone bits and PDC (Polycrystalline Diamond Compact) cutters substrates), hardness gradients obtained can reach 450 HV on 25 mm. Such gradients development is passed through a better understanding of kinetics and phenomena occurring during imbibition and reactive coating. In case of PDC cutters, influence of HPHT process parameters, allowing diamond table synthesis, on the WC-Co substrate gradient, generated by reactive imbibition, was studied. This work was also interested in gradient effect on the obtained diamond tables properties. After mechanical tests, graded WC-Co inserts and graded PDC cutters show a significant increase of both wear resistance (from 30 to 100%) and impact resistance (from 20 to 40%).
224

Marketingový výzkum nového trhu pro společnost RYTMIK s.r.o. / Marketing Research on the New Market for Company RYTMIK s.r.o.

Geyerová, Vladimíra January 2012 (has links)
The master thesis is undertaking marketing research for company XXX, Ltd. which is providing hobby groups for children in kindergartens. This master thesis is specifically focused on marketing research of a new market Hodoninsko. This thesis is including analysis of external and internal environment, comparison of the plan with reality and proposals of how to improve the company operations.
225

Vliv úpravy povrchu borem dopovaných diamantových elektrod na elektrochemickou oxidaci fenolu a jeho derivátů / The influence of the surface pretreatment of boron doped diamond electrodes on electrochemical oxidation of phenol and its derivatives

Hnízdilová, Lucie January 2021 (has links)
The aim of this thesis is the study of electrochemical oxidation of para-substituted phenol derivates using cyclic voltammetry (CV) and ,,direct current" voltammetry (DCV) on boron-doped diamond electrode (BDD) and comparison with some analogous meta-substituted compounds. Among the studied substances were p-cresol, 4-methoxyphenol, 4-hydroxybenzoic acid, 3-(4-hydroxyphenyl)propionic acid, 4-nitrophenol, 4-chlorophenol and 3-(trifluoromethyl)phenol. The oxidation of the analytes was performed in an acidic (pH 2,0) and basic (pH 11,0) Britton-Robinson buffer on mechanically polished, oxidated and hydrogenated surfaces. Another subject of the thesis is to analyze the influence of different substituents, characterized by the Hammett constant, on the oxidation potential of selected phenols. They are oxidized at more positive redox potentials in acidic media, than in basic media, where they are dissociated. The oxidation on the polished and hydrogenated surfaces were similar, whereas were shifted to higher values on the oxidated surface. Further, the signal intensity decreased on the oxidated one, and the oxidation of phenols was not recognizable in basic media. The passivation of the electrode was less significant in pH 2,0 buffer. The best result of Hammett correlation was achieved on a polished and...
226

Návrh stopkové frézy s břity z PKD / Design of the PKD cutting edge cutter

Křehlík, Luboš January 2018 (has links)
The thesis deals with the design, construction, production and testing of cutters with polycrystalline diamond cutting edges. Polycrystalline diamond is a suitable cutting material for machining very abrasive materials such as aluminum alloys or composite materials. The design of the tool is focused on the application of the chip breaker on the front of the tool. The aim of the solution is to reduce the cutting force in the machining of the aluminum alloy used in the aerospace industry. The first part of the thesis deals with problems related to milling technology. The practical part describes the design and construction of prototype cutting tools. Three tools were designed for experimental measurement. The technology of cutting tools made from super hardened cutting materials with laser technology is presented. The experimental part of the thesis is a measurement of the cutting force according to cutting parameters and machined material.
227

Supertvrdé řezné materiály a jejich efektivní využití / Superhard cutting materials and theirs effective use

Martincová, Zdeňka January 2008 (has links)
Diploma thesis is intended on a polycrystalic diamond and a pocrystalic cubic boron nitride from the standpoint of their description, physical, mechanical and cutting properties, use and contemporary trends of development at renowned producers of tools and tool materials. The aim of the work was a complex working of conditions (type of cutting material, cutting conditions), which are recommended by choice producers for the effective turning applications their kind of superhard tool materials.
228

Supertvrdé řezné materiály a jejich efektivní využití / Superhard cutting materials and theirs effective use

Stradějová, Alena January 2009 (has links)
The master’s thesis is aimed at superhard cutting materials (polycrystalline diamond and polycrystalline cubic boron nitride) and their effective utilization. It describes the characteristics and production of these materials and evaluates product ranges of the most significant producers of tools and tool materials in given area. It further compares working conditions of selected world's producers which are related to the growing utilization of these materials in machining process. The thesis also deals with the cutting power of tools and provides a technical-economic assessment of the discussed issue.
229

Supertvrdé materiály a jejich efektivní využití / Superhard cutting materials and theirs effective use

Grausgruber, Jiří January 2010 (has links)
n the first part of this diploma thesis there are described basic findings about superhard cutting materials (sorts, notation, structure, physical-mechanical properties, usage, production) and evaluates this tool of material from the aspect of cutting ability. The second part focused on complex data processing about assortment of superhard cutting materials of significant tools materials producers and comparison of work conditions (kind of machined ma-terials, cutting conditions), which are recommend for effective turning applica-tions by producers.
230

Lokalizované povrchové plazmony: principy a aplikace / Localized Surface Plasmons: Principles and Application

Kvapil, Michal January 2010 (has links)
The diploma thesis deals with plasmonic nanostructures for visible eventually near-infrared region of electromagnetic spectrum. At first, there are discussed basic terms which are necessary for description of plasmonic nanostructures and their properties. Then the resonant properties of gold nanoantennas on a fused silica substrate and in proximity of nanocrystalline diamond are addressed. FDTD simulations are used for an assesment of resonant properties and local electric field enhancement of these nanostructures. Possible manufacturing methods of the antennas and techniques for the measurement of their properties are mentioned at the end of the thesis.

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