National Repository of Grey Literature 25,432 records found  1 - 10nextend  jump to record: Search took 0.65 seconds. 

Conductivity of carbon materials for alternative energy sources
Tichý, J. ; Novák, V. ; Barath, Peter
Object of this work was prepared electrodes with carbon materials and investigate their electrical properties.

Evaluation and motivation in public administration
Vašíčková, Natálie ; Mitwallyová, Helena (advisor) ; Vláčil, Jan (referee)
The theme of the bachelor thesis is the evaluation and motivation of employees in public administration. The introductory part outlines the evaluation and motivation of employees on a general level, and then describes the specifics applicable for public administration. The practical part is focused on the evaluation and motivation systems used at selected institutions of public administration. It aims to assess these systems, suggest possible recommendations and find out whether the systems in use include modern management methods, such as evaluation interviews, competency models and regular system of employee evaluation as such. The research method consisted of interviews with human resources managers at selected institutions of public administration. Complementary information was obtained from materials created by these institutions themselves. All institutions of public administration are governed by Act No. 234/2014 Coll. on Civil Service, enshrining the evaluation of state employees. However, it depends on whether employees are evaluated formally, or if additional evaluation tools beyond the framework of the law are deployed, e.g. competency models. Officials of territorial authorities are subject to Act No. 312/2002 Coll., which does not explicitly define employee evaluation, yet employees are evaluated at many regional as well as local administration units. The results of the research survey confirmed that modern management methods are used in public administration and that the evaluation systems do not have any significant shortcomings.

Description of the older school age boys dental injuries in České Budějovice region and proposal of the health education materials.
TOBOLKOVÁ, Andrea
Thesis deals with the problem of the older school age boys dental injuries in České Budějovice region. The injury means: ?sudden damage of the health by effect of external factors which exceed adaptation options of the human body?. In the sphere of dental injuries the children is the most jeopardized group of population. The most often reason for the children injuries is their imperfect stability. In case of older children and young people there are injuries mostly caused by sport. Teoretical part of my thesis is focused on definition of older school age as well as on anatomy and teeth physiology. The part of thesis also is the enumeration of dental injuries and its treatment. I also mention prosthetic dentistry and the influence of accidents on individual physical and mental health. At the end of teoretical part there is mentioned process of the injured examination, posttraumatic dental hygiene and patient nutrition after teeth accident. Research part finds with the help of questionnaire survey the kinds of dental accidents, circumstances of injuries formation and the influence of accidents on individual physical and mental health in specific age category. The questionnaire survey was evaluated and processed in grafical part of thesis. The part of thesis also is health and educational material which helps to rise the quality of dental hygiene and also contributes to the prevention of dental accidents formation of second degree students at primary schools.


Multi-functional composites with integrated nanostructured carbon nanotubes based sensing films
Slobodian, P. ; Pertegás, S.L. ; Schledjewski, R. ; Matyáš, J. ; Olejník, R. ; Říha, Pavel
Carbon nanotubes are exceptional nano-objects with respect to their remarkable properties, holding great potential in new polymeric materials design with unique characteristics. To illustrate it, the conventional glass reinforced epoxy composite is combined with a layer of entangled network of carbon nanotubes deposited on polyurethane non-woven membrane. The prepared nano-composite is studied for their diverse mjulti-functional applications involving extension and compression strain sensing composite, remoulding by means of resistance Joule heating and radiating as a planar micro strip antenna operating at frequencies of 2MHz up to 4GHz.

HYDROGENATION PROPERTIES OF BALL-MILLED Mg-Ti-C-Zr COMPOSITE
Král, Lubomír ; Čermák, Jiří ; Roupcová, Pavla
The hydrogen storage properties of ball-milled Mg-Ti-Zr-C composite (1.8 wt.% Ti, 1.9 wt.% Zr and 0.2 wt.% C) were investigated. It has been previously shown, that the addition of Ti, Zr and C improved its storage properties. This beneficial effect of additives upon hydrogen storage properties can be explained by catalysis by the particles rich in Ti or Zr located on the surface of Mg grains. They provide effective pathways for the hydrogen diffusion into the MgH2. The morphological and microstructural characteristics were investigated by scanning electron microscopy and by X-ray diffraction. The hydrogen sorption was measured by Sieverts method using Setaram PCT-Pro device. In this paper, sorption behaviour of the composite after ball-milling and after aging on the air was compared. The ball-milled composite adsorbed 3.5 wt.% H2 within 10 min at 623 K. However, hydrogen storage capacity of the composite aged on the air for 7 months remarkably decreased: The aged composite adsorbed within 10 min only 2 wt.% H2 at 623 K and the sorption capacity decreased from 4.7 wt.% H2 to 2.1 wt.% H2.

INFLUENCE OF LASER CUTTING AND PUNCHING ON MAGNETIC PROPERTIES\nOF ELECTRICAL STEEL M470-50A
Bulín, Tomáš ; Švábenská, Eva ; Hapla, Miroslav ; Ondrůšek, Č. ; Schneeweiss, Oldřich
Electrical steel M470-50A belongs to the most often used materials in electrical machines. Due to this fact, it is desirable to know the magnetic parameters after processing raw sheets into the required shape. Basic parameters of mechanical, electrical, and magnetic properties of the sheets are usually obtained from the producer but the magnetic properties are changing in dependence on additional machining processes. The aim of this study is to describe changes in parameters of magnetic behavior after punching, laser and spark cutting of the original sheets. The basic information of structure was obtained by optical and scanning electron microscopy. The magnetic parameters were acquired from the measuring of magnetic hysteresis loops in dependence on saturation fields and frequencies. The results are discussed from the point of view of applied\ncutting technology with the aim to obtain the best magnetic parameters and consequently a higher efficiency of the final product. Results can be used as input parameters in simulation of the electrical machine.

Changes in structure and phase composition in the surface of tram rail
Švábenská, Eva ; Roupcová, Pavla ; Schneeweiss, Oldřich
We have investigated structure and phase composition of surface layer of tram rails after long time running and the results were compared with those obtained on the original part of material. Changes due to effects of severe plastic deformation together with thermal shocks by friction process were expected. The information about structure and phase composition was obtained by optical and scanning electron microscopy, X-Ray Powder Diffraction, Mössbauer Spectroscopy and Glow Discharge Emission Spectroscopy (GDOES) and this was completed by microhardness measurements. The results show that the surface layer in comparison with the original material exhibits important changes in grain structure, an increase in microhardness and high content of iron oxide and hydrooxides. According to the depth profile of the chemical composition measured by GDOES there is an increase in carbon content in the surface layer which can be effect of up-hill diffusion.

STRAIN ENGINEERING OF THE ELECTRONIC STRUCTURE OF 2D MATERIALS
del Corro, Elena ; Peňa-Alvarez, M. ; Morales-García, A. ; Bouša, Milan ; Řáhová, Jaroslava ; Kavan, Ladislav ; Kalbáč, Martin ; Frank, Otakar
The research on graphene has attracted much attention since its first successful preparation in 2004. It possesses many unique properties, such as an extreme stiffness and strength, high electron mobility, ballistic transport even at room temperature, superior thermal conductivity and many others. The affection for graphene was followed swiftly by a keen interest in other two dimensional materials like transition metal dichalcogenides. As has been predicted and in part proven experimentally, the electronic properties of these materials can be modified by various means. The most common ones include covalent or non-covalent chemistry, electrochemical, gate or atomic doping, or quantum confinement. None of these methods has proven universal enough in terms of the devices' characteristics or scalability. However, another approach is known mechanical strain/stress, but experiments in that direction are scarce, in spite of their high promises.\nThe primary challenge consists in the understanding of the mechanical properties of 2D materials and in the ability to quantify the lattice deformation. Several techniques can be then used to apply strain to the specimens and thus to induce changes in their electronic structure. We will review their basic concepts and some of the examples so far documented experimentally and/or theoretically.

ELECTRON BEAM REMELTING OF PLASMA SPRAYED ALUMINA COATINGS
Matějíček, Jiří ; Veverka, J. ; Čížek, J. ; Kouřil, J.
Plasma sprayed alumina coatings find numerous applications in various fields, where they enhance the properties of the base material. Examples include thermal barriers, wear resistance, electrical insulation, and diffusion and corrosion barriers. A typical structure of plasma sprayed coatings, containing a multitude of voids and imperfectly bonded interfaces, gives them unique properties - particularly low thermal conductivity, high strain tolerance, etc. However, for certain applications such as permeation barriers or wear resistance, these voids may be detrimental.\nThis paper reports on the first experiments with remelting of plasma sprayed alumina coatings by electron beam technology, with the purpose of densifying the coatings and thereby eliminating the voids. Throughout the study, several parameters of the e-beam device were varied - beam current, traverse velocity and number of passes. The treated coatings were observed by light and electron microscopy and the thickness, structure and surface morphology of the remelted layer were determined and correlated with the process parameters. Based on the first series of experiments, the e-beam settings leading to dense and smooth remelted layer of sufficient thickness were obtained. In this layer, a change of phase composition and a marked increase in hardness were observed.\n