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Study of competitiveness of spinach sorrel (\kur{Rumex tianshanicus x Rumex patientia}) against weeds
KOLLMANN, Milan
The sorrel, Rumex OK-2 is able to produce a large amount of biomass, suitable for feed and energy purposes as well. The possibility of the spread of this crop in the wild is the subject of frequent discussions. The aim of this work was to evaluate the competitiveness of Rumex OK-2 to weeds and its ability to spread to new locations in the field. For the field research was chosen 12 years old Rumex OK-2 stand, which is the oldest one in the Czech Republic. Determination of coverage and weed presence was done by the weight method. Rumex OK-2 was not able to spread to new places.
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The Study of hydration models on platinum complexes important in anticancer cure
Bradáč, Ondřej ; Burda, Jaroslav (advisor) ; Záliš, Stanislav (referee)
In this work, there are studied some biologically important platinum complexes, cisplatin analogues, with central platinum atom in state Pt(II), or Pt(IV). I concentrated on the hydration processes of the examined complexes. Thermodynamical and kinetical aspects of reactions were studied and NPA charge analyses were carried out, too. All computations were performed on DFT level with B3LYP functional. All reactions were considered in vacuum. Supermolecular approach was used for energy calculations.
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Small-Volume Reactive Metal Alloys Prepared by Electron Beam Melting
Zobač, Martin ; Vlček, Ivan ; Zobačová, Jitka ; Rek, Antonín
The paper deals with the preparation of small volumes of reactive metal alloys (particularly titanium), utilizing an electron beam as the heat source. The melting was performed in a vacuum environment in order to prevent the compounds from reacting with atmospheric components. The water-cooled crucible avoids any contamination of the alloy, which would have otherwise arisen during the heating of the materials. The composition of resulting alloys were then investigated by energy-dispersive X-ray spectroscopy
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Study of Influence of Segregated Impurities on Magnetism of Grain Boundaries and Free Surfaces in FCC Nickel and Cobalt
Všianská, Monika ; Vémolová, H. ; Šob, Mojmír
We present an ab initio study of segregation of 12 nonmagnetic sp impurities (Al, Si, P, S, Ga, Ge, As, Se, In, Sn, Sb and Te) at the Sigma5(210) grain boundary (GB) and (210) free surface (FS) in ferromagnetic fcc nickel and cobalt. We analyze their effect on structure, magnetic and mechanical properties. We determine the preferred segregation sites of the impurity atoms, their segregation enthalpies and strengthening/embrittling energies with their decomposition into the chemical and mechanical components. In this contribution, we focused on the influence of segregated impurities on the magnetic moments of neighbouring atoms, the changes in the density of states and why the magnetically dead layers may be present in nickel but not in the cobalt.
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Study of photon strength functions from thermal neutron capture
Bauer, Karel ; Krtička, Milan (advisor) ; Cejnar, Pavel (referee)
A subject of this thesis is to gain information on absolute photon strength function at gamma-ray energies around 4 - 8 MeV in two Gadolinium isotopes. This energy range is known as a ''low-energy'' tail region of E1 resonance. The absolute photon strength function is obtained from comparison of the sum of intensities of transitions and the number of transitions observed in thermal neutron capture on $^{155}$Gd and $^{157}$Gd with prediction from statistical model under various assumptions on photon strength functions and level densities. Powered by TCPDF (www.tcpdf.org)
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Unfolding of energies of fusion products measured by the activation probe at JET
Ficker, Ondřej ; Mlynář, Jan ; Bonheure, G. ; Murari, A. ; Popovichev, S.
Providing a detection method for diagnostic of charged fusion products in tokamaks presents a major challenge, while its absolute calibration with a sufficient accuracy and its capability to withstand harsh fusion reactor environment will be required. A novel type of detector that meets most of these requirements, based on an activation probe, was tested in JET and other European facilities. This probe proved to be extremely robust due to its simple construction. It is equipped with samples of well defined isotopic abundance. The amounts of activated nuclei due to the reactions in these materials could be measured via ultra-low-level gamma spectroscopy. The feasibility of the proton spectrum reconstruction from measured activities is examined in this contribution with the help of the algorithm based on the Tikhonov regularisation constrained by minimum Fisher information. The reliability of the method was previously illustrated using synthetic proton data.
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Multiple Sulfidation/Regeneration Cycle Tests for Advanced Fuel Conversion Process by 20 wt%Fe2O3/Al2O3 Sorbent
Huang, C.Y. ; Chyou, Y.P. ; Svoboda, Karel
In this study, 20 wt%Fe2O3/Al2O3 was used as a sorbent to perform multiple sulfidation/regeneration cycle tests in a fixed-bed reactor under simulated hot syngas conditions. The physical properties of sorbents were analyzed by X-ray diffraction (XRD), inductively coupled plasma atomic emission spectrometry (ICP-AES), BET, and SEM/EDS. ICP-AES results indicated that the composition of metal oxide was close to the theoretical value. Multiple sulfidation/regeneration cycle tests showed that the 20wt%Fe2O3/Al2O3 can be regenerated and thus reused after the oxidation process. Due to the sulfidation reaction, colour change of the 20 wt%Fe2O3/Al2O3 sorbent was observed, from the original red to black. After six sulfidation-regeneration cycles, the sulfur capacity of the sixth cycle remained approximately on a level of 68% of the sulfur capacity in the first cycle. The BET analysis showed that the surface area decreased as the cycle number increased. The sulfidation-regeneration cycles were coupled with endothermic-exothermic reactions, which probably caused sintering of the sorbent, decreasing its surface area and sulfur capacity.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22014082908321 - PDF
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Study of the impact of the new energy block Domoradice on local climate II
Sokol, Zbyněk ; Řezáčová, Daniela
The study stems from a previous work, where we used a mathematical model CT-PLUME / DOM. It is a basic model CT-PLUME adapted to assess the effect of mechanical cooling towers located in Domoradice on the model area. This study differs from the previous one in two respects: it processes 3-year period (2013, 2014 and 2015) and in addition to the basic climatic characteristics pays attention to icing. For this study, the basic module used before should be extended to model the conditions for the formation of ice in the vicinity. The final version of the model used in this study is referred to as CT-PLUME / DOM-2.
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Excited States of Carotenoids and Their Roles in Light Harvesting Systems
KEŞAN, Gürkan
Carotenoids are an extensive group of natural pigments employed by a majority of organisms on earth. They are present in most organisms, including humans, but can be synthesized only by plants and microorganisms. They perform two major roles in photosynthesis, often in partnership with the more prevalent chlorophylls (Chls) / bacteriochlorophylls (BChls): light-harvesting and photoprotection. Carotenoids absorb radiation in a spectral region inaccessible to Chls and BChls and transfer the absorbed energy to (B)Chls which, in turn, funnel it into the photosynthetic reaction center (RC). It is determined that the structures and dynamics of excited states of carotenoids found in photosynthetic proteins provide an explanation of their roles as light-harvesting and photoprotective agents. The conjugation length and the type of carotenoids play a big part in understanding the energy transfer from carotenoids to Chls and BChls, because excited-state properties of carotenoids are affected by number of conjugated C=C bonds and their structures. An accurate description of these states is, therefore, the crucial first step in explaining carotenoid photochemistry and understanding the interactions between carotenoids and other molecules in photobiological processes. The research in this thesis, femtosecond ultrafast transient absorption spectroscopy was used to study the light-harvesting function of carotenoids both in solvent and protein environment. The findings were supported with computational methods. Based on spectroscopic indications, the light-harvesting function of carotenoids has a bearing on their structures, and specific light-harvesting strategies are explicitly dependent with the structure of the light-harvesting complexes.
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Preparation of Magnesium Silicide from Recycled Materials for Energy Storage.
Bumba, Jakub ; Dytrych, Pavel ; Šolcová, Olga ; Koštejn, Martin ; Fajgar, Radek ; Maléterová, Ywetta ; Kaštánek, František
Recycling technologies help to save energy, materials and environment. This is the main reason of their popularity. The recovery of semiconductors and metals depends on recycling treatment. A new multi-step technology, which enables to obtain pure silicon and hydrogen from waste materials,is reported in this study. The only by-product is magnesium phosphate, which is a desired fertilizer. Magnesium silicide was successfully prepared from milled silicon photovoltaic (PV) panels and milled Mg obtained from the scrap. The formed magnesium silicide was then hydrolysed by phosphoric acid to form a mixture of silanes. Gaseous products (silanes) were separated by cooling below their boiling temperature by liquid nitrogen and then thermally decomposed by a hot wire, e.g. Pt.This treatment leads to pure silicon and hydrogen release. In this study a deep-in characterization by various methods spectroscopy, Scanning Electron Microscopy (SEM) with Energy Dispersive X- Ray spectroscopy (EDX), etc.) of prepared samples was also done to explain the individual influences, e.g. reaction temperature and atmosphere.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22016111814301 - PDF
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