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Measurement of nanoparticles in 3D printing using FFF/FDM technology
Klouda, Karel ; Kubátová, Hana ; Nechvátal, Marek ; Bátrlová, Kateřina ; Roupcová, Petra
For additive manufacturing, where the material is prepared by depositing thin layers, the simplified term 3D printing is used. This process releases volatile organic compounds and ultrafine particles into the air. A number of measurements have been published on this topic for a given type of printer with a specific type of thermoplastic. The procedure for the measurement of nanoparticle concentrations (10-700 nm) and their mean diameters can be called "field" because it was carried out in a real environment with mass deployment of FFF/FDM 3D printing, with the measuring equipment moving between printers in different areas and activities: in the production of parts to be assembled in the printers; in the production of components for shields during the lockout associated with the covid-19 pandemic; in the creative workshops and laboratories of Průsa Research. The aim of these measurements in real situations was to find measures to reduce the concentration of nanoparticles. The evaluation of the results was carried out in accordance with ISO/TR 27 628 and provided for the design of technological and organisational measures to reduce the concentrations.
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Emission of nanoparticles in the nanotextile industry
Nechvátal, Marek ; Klouda, Karel ; Kubátová, Hana ; Roupcová, Petra ; Bátrlová, Kateřina
We encounter smoke quite regularly in our lives. Smoke consists of gaseous, liquid and solid components that are produced by the combustion/oxidation of fuel. The chemical composition of smoke depends not only on the fuel used but also on a number of other parameters (operation, technology, atmospheric effects). The chemical composition of smoke is therefore variable and cannot be easily characterised. The combustion of wood releases into the atmosphere not only unconsumed air but also wood particles, CO2, methane, volatile organic compounds, trace elements and ultrafine particles. Measurements are published on this topic for a given type of combustion technology with a specific fuel type. The procedure for measuring the concentration of nanoparticles (10-700 nm) in wood smoke and their mean diameters can be called "field". The aim of these measurements in real situations was to find and describe sources of elevated nanoparticle concentrations. Substantial quantitative information on the occurrence of nanoparticles in wood combustion in different types of wood burners was obtained in the field under real climatic conditions, typical of the winter season in Central Europe, when most domestic heating takes place. Thus, wood burning in households in predominantly agricultural areas of the Czech Republic can be considered as a major source of outdoor air pollution, but can also have a significant impact on the deterioration of indoor air quality. At the same time, it can be assumed that the negative impact of nanoparticles on human health in areas polluted by wood smoke is weaker than the impact elsewhere - in industrial, more polluted areas.
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Toxicity of nanotextiles as respirators waste to Daphnia Magna
Slaný, Jan ; Roupcová, Petra ; Pavlovský, Jiří ; Klouda, Karel
In recent years, the prevalence of nanotubes has increased due to the covid-19 disease situation worldwide. Nanotextiles are used in the form of face masks and respirators, which are a source of environmental pollution by nanoparticles. The aim of this paper is to perform ecotoxicological tests according to European standards and Czech legislation. First, non-woven fabrics are briefly described and a small planktonic crustacean (Daphnia magna S.) is introduced. The second part focuses on the experiments themselves and their results. In all cases, the nanotextiles tested did not have a toxic effect on the organisms, but a reaction could be observed. Further tests will be carried out to explain and clarify the effects.
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Diagnostics of lexical and semantic level of language in preschool age
Malechová, Veronika ; Šulová, Lenka (advisor) ; Morávková Krejčová, Lenka (referee)
This theses deals with diagnostic of speech development of pre-school children. Its focus is on lexical-semantic language level. The goal of my work is to trace and map diagnostic possibilities in the lexical- semantic area of of pre-school children and to introduce the international PPVT test , considering its adaptation into czech language environment. Theses consists of two parts - the theoretical and empiric. Theoretical part is concern with the most important theories and personalities in the speech development and the process of experiencing language, characteristics of pre-school period, ontogenesis of speech and the ways to evaluate vocabulary and semantics in Czech and overseas. The empiric part examines the usages of PPVT in czech environment. The survey was realised by quantitative research, using datas from 236 tested individuals. The PPVT was adapted into czech language and given to preschool children, whose results were compared with the results of american children. The outcomes of the empiric part could be a solution for future research in the area, with the purpose of adapting a testing- language instrument into czech language and widening the limited possibilities in the field of language and speech development evaluation. Keywords: ontogenesis of speech, pre-school period,...
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Maternal investment and reproductive strategy in domestic horses
Komárková, Martina ; Bartošová, Jitka (advisor) ; Šumbera, Radim (referee) ; Vlček, Kamil (referee)
The aim of my doctoral thesis is the detailed study of the behavioural and sociobiological principles associated with the period of lactation. Suckling data covering almost 80 foals of domestic horse (Equus caballus) was obtained within four years of observation in the National Stud in Kladruby nad Labem, Czech Republic. The data were evaluated together with the reproductive history of the mothers, their agonistic interactions and following analysis of the dominance position of subadult foals. The first study describes longer suckling (greater maternal care) in dominant mares compared to submissive ones. Dominant mares are also less disturbed during nursing, whereas they terminated the nursing of submissive mares more often. A possible competitive advantage for the offspring of dominant mares may arise from such behaviour. The second paper enlightens the reproductive strategy of mares facing double maternal investment; suckling of the foal and pregnancy at the same time. I found out, contrary to the expectations, that the pregnant mares neither suckled their foals less nor terminated more suckling compared to non-pregnant herdmates. They may try to compensate their suckling foal with the perspective of its early weaning due to ongoing pregnancy. In the third and fourth manuscript I studied, how...
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Biology of the soldier caste in the termite genus Prorhinoterme (Isoptera: Rhinotermitidae)
Hanus, Robert ; Štys, Pavel (advisor) ; Žďárek, Jan (referee) ; Korb, Judith (referee)
Ontogeny of soldiers in Prorhinotermes simplex The soldiers were found to develop from larvae of the second up to the eighth instar, via a short (13-17 days) presoldier stage. The early soldier instars were found exclusively in incipient colonies while the mature colony contained late instar soldiers only. The first soldiers occur early in the incipient colonies; as soon as one year a er the establishment of these colonies a high proportion of soldiers was observed, which is comparable to that in mature colonies. The abrupt change in the external anatomy occurs in two steps. During the larva-presoldier moult, the head increases in length but only slightly in width. During the presoldier-soldier moult, both the length and width of the head increase markedly and the typical cordate shape is attained; the relative size of the pronotum increases considerably. The long falcate mandibles develop mainly during the larva-presoldier moult. One antennal segment is added during these two moults. With increasing instar age of soldiers a relative increase of the pronotum and the head size in its posterior region was observed. No functional differences in external anatomy were found among the six soldier instars. The composition of the frontal gland secretion is similar in the six soldier instars, an...
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Taxation of income from employment: Real Impact of Legislative Changes - case study
Marková, Diana ; Kemény, Irena (advisor) ; Hollmannová, Monika (referee)
This paper discusses the development of income tax of employees. The aim of this work is to model the real impact of legislative changes in the Czech Republic on the actual tax burden of employees with different incomes and propose optimal solution of tax calculation. The modelling is based on data containing gross salary, applicable tax allowances and tax reliefs for each employee of concrete production company in 2012. For the other years, the data are modelled from the given set using inflation. For comparison of the actual tax burden I use the effective tax rate, implicit tax rate and net implicit tax rate. The results of the calculations show that the tax deductions and the minimum and maximum base for social and health security contributions have the biggest effect on the tax rate. In the absence of tax deductions, the real tax burden for most employees according to the effective tax rate would have been almost constant over time. In fact, in terms of the effective tax rate the tax burden has declined slightly thanks to an increase in tax deductions. The results also show that the biggest differences in tax burden among employees are due to the (non) application of tax deductions.
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Palaeoecology of selected localities of the Whetstone Horizon
Libertín, Milan ; Kvaček, Jiří (advisor) ; Teodoridis, Vasilis (referee) ; Cleal, Christopher J. (referee)
Palaeoecology of selected localities of the Whetstone Horizon In frames of the present thesis taphonomical and paleoecological processed were described in selected localities of whetstone horizon. Fossil plant assemblage known from the locality Štilec represents plant community buried in situ by volcanic ash after volcanic explosion (Pennsylvanian, Bolsov). Plant community exhibits relatively low diversity assemblage of herbaceous and subarborescent plants. This unique taphocoenose was interpreted as pioneer assemblage growing in partly drained lake. In the locality Ovčín the peat bog of Lower Radnice Seam was buried during the same volcanic eruption by volcanic ash. Up to now 5 excavations were recovered of the area of seats over 150 m 2 on two sites which are approximately 40 m distant from each other. In this area 27 morphotaxa of fossil plant was recorded. They represent 20 whole plants. Fossil plant remains represent fossil plant assemblage dominated by lycopod plants of planar (rheotrophic) swamp situated in narrow palaeovalley with active fluvial system. Second part of the thesis is focused on systematic descriptions of fossil plant taxa from localities of the Whetstone horizon. A monotypic genus Huttonia and species Huttonia spicata from Class Sphenopsids was emended. Further there were described...
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Contaminant mobility and toxicity in soil profiles in the Mufulira smelting area (Copperbelt, Zambia)
Konečný, Ladislav ; Ettler, Vojtěch (advisor) ; Frouz, Jan (referee)
ii SUMMARY The smelter in Mufulira is one of the several active copper smelters in Copperbelt area in Zambia. It had operated for almost 70 years and during that period all offgas and dust were released into the atmosphere. Six profiles, three of them beneath trees, were sampled in the distances of 3.6, 8 and 24 km from the smelter. Each profile consisted of 9-10 layers collected continuously from the topsoil till depth of 60-70 cm. Following parameters were measured for each layer: pH, TC, TS a CEC, then total concentration of Ag, As, Al, Fe, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sb, Se, Sn, V a Zn and extractability by EDTA. The total concentrations of metals/metalloids were measured by ICP-OES and quadrupole- based ICP-MS. TC and TS were determined by thermal analysis and mobility of metals was assessed according to their extractability by EDTA. The aim of this work was to compare vertical distribution and mobility especially of these metals Co, Cr, Cu, Pb, V and Zn among profiles. Finally a standardized toxicity test was performed with ten selected layers (include all top soils) from all profiles. This reproductive test with Enchytraeus crypticus reflected how tested soil samples were suitable for living and reproducing this specimen of invertebrates. Generally the total concentrations of metals decreased in...
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Taxonomy of species of the genus Lachnum s.I. in Central Europe
Chlebická, Markéta ; Holec, Jan (advisor) ; Pažoutová, Sylva (referee) ; Baral, Hans-Otto (referee)
Aims of the thesis The generalobjectiveof thethesisv/asto taxonomically evaluatethe rich materialof Lachnurn s.l. depositedin Czech herbaria,as well as the personal ťreldcollections. In the case of taxonomic or nomenclatural problems, the problematic groups were studied in detail. Various methods were used to solve the taxonomic problems and important collections from other herbariawere also studied. Outline of the thesis Problematic groups in Lachnum. I paid attentionto lignicolous and herbicolous species of Lachnum and to the group of Lachnum pygmaeum (Article III, VII) from the taxonomicpoint of view. Field collections of the whole spectrumoťLachnum specieswere included to the check-list (Article I). Species concept in Capitotricha. Central European species of Capitotricha with asci arising from simple septa were sequenced and a larger set of data supplementingthe previously known sequencewas obtained and analysed. Interesting data on Capitotricha species from Nothofagus from southern hemisphere were obtained. Long-spored lignicolous species of the genus Erioscyphella Kirschst. close to Lachnum and Capitotricha from the tropics and subtropics were also studiedanddiscussed. Taxonomy of Trichopeziza. Tbere was a lot of confusion connected with the name Peziza sulphurea Pers. At first, it was used for a...
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