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Calibration of indirect methods for maesurement of properties of alkali activated concretes
Vrba, Pavel ; Kocáb, Dalibor (referee) ; Bílek, Vlastimil (advisor)
This work solves creation of calibration relations to determine cube compressive strength, dynamic and static elastic modulus of alkali-activated concrete by non-destructive methods. Alkali-activated concrete is spoken of as a new material used in civil engineering. It shows different properties than normal concrete based on Portland cement. That's why the modification of common calibration relation seems necessary. Fresh concrete was made in the concrete plan ŽPSV a.s., Uherský Ostroh in three mixtures and always in the number of 18 cubes and 3 prisms. The samples were tested by impact hammer Schmidt type L, type N, SilverSchmidt PC-N and by ultrasound in 6 time periods of three specimens. After that, the cube compressive strength was determined. Status of static elastic modulus was determined in a time period of 28 days. The results are calibration relations to determine the progress of compressive strength and modulus of elasticity for each method and their combination.
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Mesophilous grassland butterflies of European interest under climate changes (Lycaena dispar, Lycaena helle, Phengaris nausithous, Phengaris teleius, Euphydryas aurinia)
Vrba, Pavel ; Faltýnek Fric, Zdeněk ; Rindoš, Michal ; Hájková, K. ; Konvička, Martin
Methodological material summarizing variants of the habitat conservation principles for butterflies inhabitting mesophilic and humid grasslands under various scenarios of climate change. The species of interest, protected by the EU Habitats Directive, are Euphydryas aurinia, Phengaris nausithous, Phengaris teleius, Lycaena dispar and Lycaena helle. It includes the predictions of suitable locations for spontaneous or assisted colonization.
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Dry grassland butterflies of European interest under climate changes (Colias myrmidone, Parnassius apollo, Phengaris arion)
Faltýnek Fric, Zdeněk ; Konvička, Martin ; Rindoš, Michal ; Sucháčková Bartoňová, Alena ; Spitzer, Lukáš ; Vrba, Pavel
The methodology summarizes the principles of the habitat conservation of several butterflies - Phengaris arion, Parnassius apollo and Colias myrmidone, species specialized to dry grasslands, rock screes and similar habitats, under different scenarios of climate change. Maps of future climatically suitable habitats are included, together with an analysis of the possibilities of assisted colonization.
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Endangered butterflies of lowland forests under climate change
Konvička, Martin ; Beneš, Jiří ; Číp, D. ; Sobík, D. ; Spitzer, L. ; Faltýnek Fric, Zdeněk ; Rindoš, Michal ; Vrba, Pavel
The material compiles conservation measures and methods for the care of endangered butterflies of open forests, protected by the EU Habitat Directive in the Czech Republic and under climate changes. These species are Euphydryas maturna, Lopinga achine, Parnassius mnemosyne, Coenonympha hero, and partially also Zerynthia polyxena. It results from predictions of vegetational and climatic changes of forest habitats, and outlooks of forest and water management conditions.
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Abundance and habitat use of reintroduced populations of the Hermit (Chazara briseis) in the Czech Republic
Pešová, Lucie ; Sedláček, Ondřej (advisor) ; Vrba, Pavel (referee)
The Hermit (Chazara briseis) belongs to the critically endangered species in the Czech Republic. Its last population survived until recently in the NPR Raná in the České středohoří Protected Landscape Area, but it has gradually declined. The specie's habitat is short-stemmed grasslands, which are maintained mainly by extensive grazing and management. Currently, these sites are declining, traditional management has changed and the sites are gradually becoming overgrown. Therefore, the reconstruction of the butterfly's habitats has been undertaken in selected localities that the butterfly used to inhabit in the past, in the České středohoří Protected Landscape Area (PR Číčov, Dlouhá hora, PP Radobýl) and in the Český kras Protected Landscape Area (Třesina, Radotín). Reintroduction of eggs and caterpillars took place in these sites in 2020-2021. The aim of the thesis was to evaluate the population abundance and habitat use of the Chazara briseis at these sites immediately after reintroduction. I estimated the size of the populations using the mark-capture-recapture method in 2020 and 2021. The size of the populations in the Lonské středohoří (Dlouhá hora and Číčov) was around 400-500 individuals with a fairly balanced sex ratio. Overflights were also recorded between these sites, which may indicate...
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XUV Spectra from High Current Nitrogen Z-Pinch Capillary Discharge.
Vrba, Pavel ; Vrbová, M.
We have performed computer modeling of the pinching plasma of capillary discharge using the 1d NPINCH code, that considers ablation of the capillary wall. At high currents we have observed that, the ablation has significant effect on the plasma electron temperature evolution and on the rate of pinch decay. To estimate the emitted spectra in XUV range, the FLYCHK code was used as a post processor. The capillary wall ablation represents the principal obstacles of recombination pumping during pinch decay.\n
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Sub-Nanosecond Laser Induced Plasma as Water Window Radiation Source.
Vrbová, M. ; Vrba, Pavel
Laser plasma created in a krypton gas puff target is studied as a source of radiation in the water window spectral range (lambda= 2.3 - 4.4 nm). The spatial development of the plasma induced by a sub-nanosecond Nd:YAG laser pulse focused on the gas puff target is modeled using 2d RMHD code Z*. Space-time distributions of plasma quantities, namely electron temperature, electron density, mass density and plasma expansion velocity were evaluated. Instantaneous spectra during the laser pulse and during plasma decay period are also calculated. Temporal evolutions of the krypton ions relative populations prove that ions from Kr21+ and Kr22+ are responsible for dominant spectral intensity emitted at a wavelength around lambda= 3 nm. Evaluated time resolved spectra are compared with time integrated spectra obtained experimentally.
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Effectivity and utilisation of different methods of moths research
Palivcová, Lucie ; Tropek, Robert (advisor) ; Vrba, Pavel (referee)
Sampling of data on moth communities is essential for our better understanding of their biology. This thesis is focused on different moth sampling methods, with a special aim to light catching as the most effective way how to attract them. Various sampling methods are described together with review of published knowledge of their effectivity, as well as advantages and disadvantages. Individual sampling is suitable for studying of preselected particular species. Interception traps are used for studying of flying corridors. Selected groups of moth can be attracted by various baits or caught by colored pan traps, bait traps and pheromone traps. Common and highly useful is attracting of moths using light. Light source can significantly affect sampling efficiency. The most species and individuals are attracted by shortwave light, but particular preferences are species and sexes specific. Understanding of methodology and moth behavior can improve study of them and should bring new knowledge of their conservation or management of moth pests.
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Calibration of indirect methods for maesurement of properties of alkali activated concretes
Vrba, Pavel ; Kocáb, Dalibor (referee) ; Bílek, Vlastimil (advisor)
This work solves creation of calibration relations to determine cube compressive strength, dynamic and static elastic modulus of alkali-activated concrete by non-destructive methods. Alkali-activated concrete is spoken of as a new material used in civil engineering. It shows different properties than normal concrete based on Portland cement. That's why the modification of common calibration relation seems necessary. Fresh concrete was made in the concrete plan ŽPSV a.s., Uherský Ostroh in three mixtures and always in the number of 18 cubes and 3 prisms. The samples were tested by impact hammer Schmidt type L, type N, SilverSchmidt PC-N and by ultrasound in 6 time periods of three specimens. After that, the cube compressive strength was determined. Status of static elastic modulus was determined in a time period of 28 days. The results are calibration relations to determine the progress of compressive strength and modulus of elasticity for each method and their combination.
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Cold tolerance of mountain and lowland butterflies
VRBA, Pavel
The thesis deals with ecophysiology of overwintering larvae of two butterfly genera, Colias and Erebia. It focuses on identification of supercooling point, survival of various low temperature regimes and composition of cryoprotective substances. Results are presented in the context of distributional limits of individual species, their habitat requirements and their potential endangerment due to environmental and habitat changes.
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