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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.
101

Aplikace spektrální analýzy v 3D hodnocení povrchů / Application of Spectral Analysis in 3D Evaluation of Surfaces

Brillová, Kateřina January 2011 (has links)
Thesis deals with the spectral analysis of 3D surface topography. The surface is described by a random function. Theoretical starting points necessary for right introduction and understanding of basic notions used within the framework of the surface topography spectral analysis are exactly formulated. They lie in the theory of random functions, the theory of the Fourier transform and the theory of signal processing. The notions mentioned are: the areal power spectral density (APSD) of a surface, the radial power spectral density (RPSD) of a surface and the angular power spectrum density (AnPSD) of a surface. These notions are introduced in their discrete form and generalized for the two-dimensional case. The thorough discussion of possible mistakes and inaccuracies which can be done during the application of spectral analysis techniques in a surface topography evaluation is performed. The procedure of APSD estimation by means of the periodogram method combined with the Welch´s method is discussed. The principle and capabilities of the optical profilometer MicroProf?FRT used for the surface topography measurement are described. Our original computer program computing APSD, RPSD and AnPSD is described too. The 3D spectral analyses is applied to surfaces generated by AWJ cutting, plane grinding and casting. We have focused our attention to AWJ cut surfaces, 3D spectral analyses of which brings new still unpublished opportunities of the surfaces topography evaluation. The influence of technological parameters on these AWJ cut surfaces topography is studied. The conclusion of the study is that results of the spectral analyses of these surfaces topography strongly depend on the technological conditions of the surfaces generation. An original procedure of the ASPD shape evaluation within individual regions of its frequency domain is mentioned. This procedure brings new substantial knowledge concerning the topography of surfaces. Results obtained from surfaces generated by plane grinding and casting are presented like examples of results from non-isotropic and isotropic surfaces.
102

Analýza hustoty lesních porostů s využitím texturálních příznaků snímků vysokého prostorového rozlišení a dat leteckého laserového skenování / Analysis of forest canopy density based on textural features of hight resolution imagery and airborne laser scanning data

Bromová, Petra January 2012 (has links)
Analysis of forest canopy density based on textural features of high resolution imagery and airborne laser scanning data Abstract The objective of this thesis is to assess the forest canopy density in the Šumava Mountains, Czech Republic. The spruce forests in this area have been suffering from the bark beetle outbreak for almost 20 years resulting in a mixture of dead and young trees, mature forest stands and peat bogs. The canopy density was evaluated using a very high spatial resolution panchromatic imagery and low point density LiDAR, combined with an object oriented approach. The classification based on three GLCM texture measures (contrast, entropy and correlation), which were derived from the image objects, resulted in a kappa index of accuracy of 0.45. Adding the information from the LiDAR data, the accuracy of the classification improved up to 0.95.
103

Studium vlivu výpalu na vlastnosti vápna / The study of the effect of burning process on the properties of lime

Urban, Karel January 2016 (has links)
At the institute of technology of building materials and components at the fakulty of civil engineering in Brno was initiated research deal with study of the effect of limestone on the progress of decarbonization. This work is an introductory study into this problems. It focuses on describing the genesis and diagenesis of limestones, their crystallography, texture and requirements for burning. Further describes the extraction and treatment of limestones before burning. In very burning is focused on its mechanism and the used furnace systems. In the experimental part is focused on the analysis of samples of limestones of various world sites in terms of petrology, geological origin, chemical composition, the content of insoluble residues, density and porosity, and analysis of formed limes, burned at 900 °C in terms of density, CO2 content and crystal size.
104

Studium biologické aktivity konopí setého / Biological study of hemp activity

HELLEROVÁ, Šárka January 2015 (has links)
The aim of my study is to evaluate the impact of seed density on yields of hemp, which was cultivated in two areas, and subsequently to assess biological efficiency of infusion from hemp on fibroblastoidal line of mammalian cells L292. Afterthat in the case of above mentioned biological test we want to find out, if the density and different parts of plant will have an impact on efficiency of extract.
105

Influence of wood structure on wood properties of tropical species

Baar, Jan January 2014 (has links)
The presented thesis is focused on aesthetical and acoustic properties of tropical wood. The discussed tropical species are utilized in Europe mainly for their unusual appearance and colour in joinery and furniture production. The irreplacable acoustic properties like low internal friction predestine specific species for production of musical instruments. The colour of six selected tropical species - jatoba (Hymenea courbaril L.), massaranduba (Manilkara bidentata A. Chev.), muiracatiara (Astronium graveolens Jacq.), angelim amargoso (Vatairea spp.), angelim pedra (Hymenolobium spp.) and angelim vermelho (Dinizia excelsa Ducke) - were analyzed and expressed in CIEL*a*b* colour space. Subsequently the samples were exposed to artificial sunlight and the light-induced discolouration rate and progress was evaluated. The colour change was rapid in zhe first hours of exposure and all species showed a similar trend in lightness (L*) change - initial darkening replaced by gradual fading. The change in chromatic parameters (a* and b*) change was specific for individual species and probably related to the chemical composition of the extractives. The overall discolouration of lighter coloured wood samples is more distinctive. The extractive content of tropical species is usually high and determines wood colour. The wood of African Padauk (Pterocarpus soyauxii Taub) and Jatoba (Hymenaea courbaril L.) was extracted in a mixture of methanol, water and acetone. The total extractives and total phenolic content was measured. Extractive content was related to colour parameters and above all to lightness in both species. The increase in extractive content leads to a lighter and more yellow colouration of Jatoba wood while African Padauk was darker with a higher amount of extractives. In Jatoba, a positive correlation was found between extractive content and the rate of discolouration. The extractives are responsible for intensive discolouration of tropical woods in contrast to light coloured woods from the temperate zone, where the yellowing is primarily caused by lignin photodegradation. The sound velocity was measured by ultrasound and resonance longitudinal method in heartwood of doussie (Afzelia bipindensis), merbau (Intsia bijuga), wengé (Millettia stuhlmannii Taub.), muiracatiara (Astronium graveolens Jacq.) and zebrano (Microberlinia brazzavillensis). The sound velocity was not related to the density in any case. Although anatomical structural characteristics as fiber length or ray ratio positively influenced it. With longer fibers and slender rays the sound velocity increased. Other acoustic properties like dynamic young modulus of elasticity, specific modulus of elasticity, internal friction and acoustic conversion efficiency (ACE) were determined and were related to measured anatomical features. The differences in composition of wood tissue of individual species were the main source of departure between the assessed relationships. The wood with longer fibers and lower frequency of rays reached lower values of internal friction. The stiffness of wood characterized by the dynamic modulus of elasticity was correlated with fiber and ray tissue. A higher volume of fibers influenced the stiffness positively, while ray volume had the opposite effect on stiffness. Positive effects of fiber length and ray ratio were found for dynamic modulus of elasticity and for acoustic conversion efficiency as well. Both values increased with longer fibers and higher ray ratio. The sound velocity is the basis of some nondestructive techniques for determination of wood mechanical properties. The comparison of density and three dynamic moduli of elasticity (longitudinal and flexural resonance method and ultrasound method) in prediction of mechanical properties was carried out. The density was evaluated as a poor predictor when the samples are not straight-grained and defect free. The interlocked grain often occurred in tropical species and its presence influences the mechanical properties of wood but not wood density. The dynamic moduli of elasticity showed strong correlation with the static modulus of elasticity. Among nondestructive techniques, the weakest correlation was found for the ultrasound method, which is probably partially explained by different measuring mechanism. The prediction of the modulus of rupture is less accurate when the dynamic modulus of elasticity is compared with the static modulus of elasticity; however, it was still good in comparison with the density model.
106

Adaptace štiky obecné (Esox lucius L.) na umělé peletované krmivo v kontrolovaných podmínkách chovu / Adaptation of northern pike (Esox lucius L.) on artificial pelleted feed under controlled conditions

HAJÍČEK, Jiří January 2012 (has links)
The main objective of this thesis is to describe and experimentally evaluate the possibility of adaptation of pike (Esox lucius L.) in controlled housing conditions and income artificial pelleted feed. The thesis is mainly based on the effect of an initial larval density of pike for adaptation and survival and the growth of larvae reared in the rearing tanks. The experiment consisted of four different densities of larvae (10, 20, 40, 80 pc of the larvae l??, which were always repeated three times. Two experiments were performed (M, H), with a length of rearing of five days. Rearing itself was conducted in twelve circular tanks with a capacity of 180 l??, the recirculation system connected to the experimental rearing facility in Vodňany FROV JU. The temperature during rearing was constant. For the first experiment the temperature was 22.3 ? 03 °C. For the second one, the average temperature was 21.5 ? 0.6 °C. The frequency of feeding was continuous (24 h) with a combination of hand feeding and feeders with a timer (at night). The illumination of the aquarium tanks was provided by fluorescent lamps, for each tank individually. The light intensity was high (210 lux) and constant during the rearing. Both experiments showed the optimal density at the initial feeding from 20 to 40 units . l??. Also, we have implemented made out performed- the basic biometric analysis of W (g) and TL (mm), the body length, size of eyes, head, jaw length, prenatal length.
107

Dopravní infrastruktura v ČR, se zaměřením na silniční a železniční / Road and railway transport infrastructure in the Czech Republic

PAUR, Lukáš January 2014 (has links)
The thesis focuses on transport infrastructure in the Czech republic. Its aiming at road, railway and combined infrastucture.It analyzes its current situation and short historical development. There is analysis focused on the density of infrastructure in european conditions and national regions in Czech Rep. Further, it analyzes the transport overload on chosen roads. Sugested solution is to move the road freigth to railway through combined transportation. Cost savings coming from lower reconstruction costs are calculated as well. In the end, there is proposal about implementation of combined transport in the region as a regional logistic center.
108

Hodnocení dopravní dostupnosti ve Středočeském kraji / Assessment of Transport Accessibility in the Central Bohemia Region

ROUBÍČKOVÁ, Zuzana January 2010 (has links)
The goal of the thesis ``Assessment of Transport Accessibility in the Central Bohemia Region{\crq}q is to analyze the transport situation and transport accessibility.
109

Fotonové silové funkce v jádře 168Er z měření gamma kaskád detektorem DANCE / Photon strength functions in 168Er from multi-step gamma cascade measurement at DANCE

Knapová, Ingrid January 2017 (has links)
Subject of the thesis is study of photon strength functions describing the gamma decay of the nucleus. During last 50 years a number of theoretical models for these quantities were proposed, however, their accuracy is still de- batable and its verification has recently been a subject of intensive experimental and theoretical research. In this work measurement of multi-step gamma cas- cades following the radiative neutron capture on target nucleus 167 Er is used to analyse photon strength functions. The experiment was performed with DANCE calorimeter located in Los Alamos Neutron Scattering Center. The experimen- tal spectra are compared with Monte Carlo simulations of electromagnetic decay using the DICEBOX algorithm, based on assumptions of Extreme Statistical Model. Comparison of experimental and simulated spectra is a fundamental tool for studying correctness of theoretical models of photon strength functions. This study provides information mainly about E1 and M1 photon strength functions, especially properties of the so-called scissor mode are analysed.
110

Rozšíření a biotopové preference strnada zahradního v České republice / Distribution and habitat preference of the Ortolan Bunting in the Czech Republic

Zeman, Vít January 2017 (has links)
The Ortolan Bunting (Emberiza hortulana) is a farmland bird species, whose population size has declined very sharply in recent decades, especia ll y in Western and Central European countries. The aim of our study in 2015 was to record where the last populations of this critically endangered species in the Czech Republic are located and also what habitat the species associated with. We examined nine areas (925 km2 in total). Two main areas of occurrence (surface mines in northern Bohemia and farmland landscape of Silesia) and two small isolated populations in central Bohemia were registered for this species. In contrast, observations in some traditional areas of its occurence (České středohoří in northern Bohemia, Hovorany-Čejkovice region in southe r n Moravia and Javoricko region in Silesia) were negative. Altogether, we counted 75-79 singing males. Our estimation of the size of the Czech population in 2015 is 75-100 singing males, which indicates further population decline compared to the last mapping in 2001-2003. Furthermore, habitat associat io ns were investigated at two spatial scales and we made habitat compar is o n between farmland and post-mining landscape. Our research highlights a high degree of flexibility in habitat selection of Ortolan Bunting and also positive association with high...

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