(Non) Linear Regression Modeling

We will study causal relationships of a known form between random variables. Given a model, we distinguish one or more dependent (endogenous) variables Y = (Y1, . . . , Yl), l ∈ N, which are explained by a model, and independent (exogenous, explanatory) variables X = (X1, . . . ,Xp), p ∈ N, which explain or predict the dependent variables by means of the model. Such relationships and models are commonly referred to as regression models. --

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

The Gargoyle

Apropriace gotiky do současného umění, formou dočasné site-specific instalace ve sklepním prostoru. Instalace se skládá ze čtyř samostatných děl, které spojuje společná tématika, která se opírá o vlastní zkušenosti a vytváří tak vlastní chrámové prostředí.Appropriation Gothic to contemporary art , in the form of temporary site-specific installations in the cellar. Installation consists of four separate pieces, which combines a common theme , which is based on his own experience and creates its own temple environment .

MIXED CORE SUBCHANNEL MODEL FOR SUBCAL AND COUPLING WITH ANDREA

This paper presents the results of an analysis of flow distribution in VVER-1000 mixed core consisting of fuel assemblies with non-identical spacing grids. The calculation was carried out using the modified subchannel code SUBCAL-AZ which allows to calculate 3D thermal-hydraulic characteristics of the coolant flow in the full core subchannel model coupled with the neutron-physical code ANDREA. This full core subchannel model was created in three variants depending on the ANDREA calculations. The first variant (homogeneous core) consisted of 163 hydraulically identical fuel assemblies TVSA-T mod.2, whereas the other variants (mixed cores) consisted of fuel assemblies TVSA-T mod.0, mod.1 and mod.2. These fuel assemblies mainly differ in types, number and axial coordinate of spacing grids and also in diameter of guide tubes. The influence of mixed core to flow distribution was obtained by comparing these variants

LATERAL COOLANT FLOW BETWEEN FUEL ASSEMBLIES IN MIXED CORES

This paper presents the results of an analysis of lateral coolant flow between adjacent fuel assemblies with non-identical spacing grids in a mixed core consisting of TVSA-T mod.1 and TVSA-T mod.2 fuel assemblies. The calculation was carried out using modified subchannel code SUBCAL which allows to calculate 3D thermo-hydraulic characteristics of the coolant flow in the full three fuel assemblies model. This full three fuel assemblies model was created in two variants. The first variant consisted of three hydraulically identical fuel assemblies TVSA-T mod.1, whereas the second variant consisted of two fuel assemblies TVSA-T mod.1 and one fuel assembly TVSA-T mod.2 which mainly differ in types, number and axial coordinate of spacing grids and also in diameter of guide tubes. The influence of mixed core to lateral coolant flow and hence coolant temperature was obtained by comparing these two variants. The power distribution was taken from presumed mixed core fuel reload calculated by macro-code ANDREA. Finally there were also provided a comparison of results achieved by subchannel analysis approach with calculation of similar problem using CFD code ANSYS CFX by TVEL, the fuel supplier

Microstructure and mechanical properties of sintered and heat-treated HfNbTaTiZr high entropy alloy

High entropy alloys (HEAs) have attracted researchers' interest in recent years. The aim of this work was to prepare the HfNbTaTiZr high entropy alloy via the powder metallurgy process and characterize its properties. The powder metallurgy process is a prospective solution for the synthesis of various alloys and has several advantages over arc melting (e.g., no dendritic structure, near net-shape, etc.). Cold isostatic pressing of blended elemental powders and subsequent sintering at 1400 degrees C for various time periods up to 64 h was used. Certain residual porosity, as well as bcc2 (Nb- and Ta-rich) and hcp (Zr- and Hf-rich) phases, remained in the bcc microstructure after sintering. The bcc2 phase was completely eliminated during annealing (1200 degrees C/1h) and subsequent water quenching. The hardness values of the sintered specimens ranged from 300 to 400 HV10. The grain coarsening during sintering was significantly limited and the maximum average grain diameter after 64 h of sintering was approximately 60 mu m. The compression strength at 800 degrees C was 370 MPa and decreased to 47 MPa at 1200 degrees C. Porosity can be removed during the hot deformation process, leading to an increase in hardness to similar to 450 HV10.Web of Science912art. no. 132

Electron scattering in HCl: An improved nonlocal resonance model

We present an improved nonlocal resonance model for electron-HCl collisions. The short-range part of the model is fitted to ab initio electron-scattering eigenphase sums calculated using the Schwinger multichannel method, while the long-range part is based on the ab initio potential-energy curve of the bound anion HCl-. This model significantly improves the agreement of nonlocal resonance calculations with recent absolute experimental data on dissociative electron attachment cross sections for HCl and DCl. It also partly resolves an inconsistency in the temperature effect in dissociative electron attachment to HCl present in the literature. Finally, the present model reproduces all qualitative structures observed previously in elastic scattering and vibrational-excitation cross sections