Study of CVD Coatings Used for Cutting Tools

Import 26/06/2013Čížek, L. Studium CVD povlaků používaných v oblasti řezných nástrojů ze slinutého karbidu, jejich vlastnosti a aplikační oblasti: VSB – Technická univerzita Ostrava, Fakulta strojní, katedra mechanické technologie, 2013 Bakalářská práce, vedoucí: Doc. Ing. Jitka Podjuklová, CSc. Ve své bakalářské práci se zabývám jedním z typů tenkých povlaků, a to CVD povlaky (Chemical Vapor Deposition), v oblasti řezných nástrojů. Tyto nástroje jsou ve většině případů vyměnitelné břitové destičky ze slinutého karbidu, používané při soustružení a frézování. V úvodu se seznámíme s historií povlakování, dále pak se slinutým karbidem a poté se zaměříme na princip této metody, typy a popis jednotlivých povlaků, jejich vlastnosti a aplikační oblasti. V praktické části jsem porovnával vlastnosti tří vzorků destiček s CVD povlakem, bylo analyzováno složení, tloušťka jednotlivých vrstev, ad-heze povlaku a měřena jeho tvrdost. Na konec byly destičky podrobeny testu trvanlivos-ti při frézování. Nejlépe vyšel vzorek č. 3. Výsledky jsou uvedeny v závěru této práce.Cizek, L. Study of CVD coatings used for cutting tools carbide, properties and application areas: VSB – Technical University of Ostrava, Faculty of Mechanical, Department of Mechanical Technology, Thesis, leader: Doc. Ing. Jitka Podjuklova, CSc. In my thesis I focus on one type of thin coatings, CVD (Chemical Vapor Deposition), in the area of cutting tools. These tools are in most cases inserts from sintere carbide used in turning and milling. In the introduction, we get familiar with history of coating and sintered carbide, then we focus on principle of this method and description of coatings types, their properties and application areas. In the practical part, I compared properties of three samples with CVD. Composition and thickness of each layer, adhesion re-sistance of coating to thermal crakcs were analysed and its hardness was measured. At the end inserts were subjected to the durability test in milling. Description, documenta-tion and results are listed at the end of this work.345 - Katedra mechanické technologievelmi dobř

Economic Geography, Regional Policy of the European Union and its Potential for the Czech Republic

Proces ekonomické integrace vede k poklesu transakčních nákladů mezi regiony a následně ovlivňuje ekonomickou geografii celého území. Podle nové ekonomické geografie může tento proces způsobit nárůst regionálních disparit spolu s růstem specializace regionů a geografické koncentrace ekonomických odvětví. Opíraje se o závěry této větve ekonomické teorie nejdříve uvádíme empirické poznatky o vývoji ekonomické geografie evropských regionů. Posléze podrobněji analyzujeme vývoj ekonomické geografie českých regionů. Docházíme ke zjištění, že regionální disparity v ČR prudce a trvale narůstají, nicméně tento průběh je způsoben především dynamikou hlavního města. Dalším závěrem naší empirické analýzy je, že český zpracovatelský průmysl prodělal v 90.letech poměrně výrazný pokles geografické koncentrace, přičemž tento proces byl doprovázen snížením míry specializace regionálních ekonomik. V posledním období však jak specializace regionů, tak i koncentrace průmyslu souhrnně spíše stagnují. V poslední části potom vyvozujeme z našich zjištění implikace pro strategii uplatnění politiky soudržnosti v České republice.Deepening of economic integration leads to a fall of transaction costs between regions and consequently affects the economic geography of the whole territory. According to the new economic geography this process can bring alongside a rise in regional inequality, in specialization of regions and in geographic concentration of industries. Taking as a basis the theoretical foundations of this branch of economic theory we first review the empirical evidence on the changing pattern of the economic geography of the european regions. Afterwards we analyze in detail the evolution of the economic geography of Czech regions. First, we find that regional disparities are sharply rising but mainly due to the dynamics of the capital city. Second, we find that the Czech manufacturing sector underwent in the 90's a relatively strong deconcentration and this process was accompanied by a decrease in the specialization of the regional economies. Nowadays both regional specialization as well as concentration of industries are on the whole rather stagnating. We then discuss the implications of our findings for the design of the Cohesion policy in the Czech republic.Institut ekonomických studiíInstitute of Economic StudiesFaculty of Social SciencesFakulta sociálních vě

FPGA-based module for SURF extraction

We present a complete hardware and software solution of an FPGA-based computer vision embedded module capable of carrying out SURF image features extraction algorithm. Aside from image analysis, the module embeds a Linux distribution that allows to run programs specifically tailored for particular applications. The module is based on a Virtex-5 FXT FPGA which features powerful configurable logic and an embedded PowerPC processor. We describe the module hardware as well as the custom FPGA image processing cores that implement the algorithm's most computationally expensive process, the interest point detection. The module's overall performance is evaluated and compared to CPU and GPU based solutions. Results show that the embedded module achieves comparable disctinctiveness to the SURF software implementation running in a standard CPU while being faster and consuming significantly less power and space. Thus, it allows to use the SURF algorithm in applications with power and spatial constraints, such as autonomous navigation of small mobile robots

Economic Geography, Regional Policy of the European Union and its Potential for the Czech Republic

Deepening of economic integration leads to a fall of transaction costs between regions and consequently affects the economic geography of the whole territory. According to the new economic geography this process can bring alongside a rise in regional inequality, in specialization of regions and in geographic concentration of industries. Taking as a basis the theoretical foundations of this branch of economic theory we first review the empirical evidence on the changing pattern of the economic geography of the european regions. Afterwards we analyze in detail the evolution of the economic geography of Czech regions. First, we find that regional disparities are sharply rising but mainly due to the dynamics of the capital city. Second, we find that the Czech manufacturing sector underwent in the 90's a relatively strong deconcentration and this process was accompanied by a decrease in the specialization of the regional economies. Nowadays both regional specialization as well as concentration of industries are on the whole rather stagnating. We then discuss the implications of our findings for the design of the Cohesion policy in the Czech republic

Study of selected properties of magnesium alloy AZ91 after heat treatment and forming

Magnesium and magnesium alloys are primarily used in aeronautical and automobile industry in large variety of structural characteristics because of their favorable combination of tensile strength (160–365 MPa), elastic modulus (45 GPa), and low density (1740 kg/m3), which is two-thirds that of aluminum. Magnesium alloys have high strength-to-weight ratio (tensile strength/density), comparable to those of other structural metals. Application, structure and mechanical properties of selected magnesium alloys were investigated

Non-Destructive Evaluation of Steel Surfaces after Severe Plastic Deformation via the Barkhausen Noise Technique

This paper reports about the non-destructive evaluation of surfaces after severe shot peening via the Barkhausen noise technique. Residuals stresses and the corresponding Almen intensity, as well as microstructure alterations, are correlated with the Barkhausen noise signal and its extracted features. It was found that residual stresses as well as the Barkhausen noise exhibit a valuable anisotropy. For this reason, the relationship between the Barkhausen noise and stress state is more complicated. On the other hand, the near-the-surface layer exhibits a remarkable deformation induced softening, expressed in terms of the microhardness and the corresponding crystalline size. Such an effect explains the progressive increase of the Barkhausen noise emission along with the shot-peening time. Therefore, the Barkhausen noise can be considered as a promising technique capable of distinguishing between the variable regimes of severe shoot peening

Laboratory Simulation of the Positron–Dust Interaction and its Implication for Interstellar Dark Clouds

We report the first laboratory experiment dealing with the interaction of a cosmic dust simulant with positrons emitted from a ^22 Na radioisotope. Measurements of a charge of micrometer SiO _2 dust grains with an accuracy of one elementary charge e revealed +1 e steps due to positron annihilation inside the grain. The observed average rate of these charging events agrees well with prediction of a model based on the continuous slowing down approximation of energetic of positrons inside the grain. Less frequent charge steps larger than +1 e were attributed to emission of secondary electrons during positron slowing down. The determined coefficient of secondary electron emission is approximately inversely proportional to the grain radius. The experimental results led us to the formulation of a possible scenario of interstellar dark clouds charging

Long Term Archiving Implementation – Slovenian Experience with

Česká společnost uživatelů otevřených systémů EurOpen.C