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Crystal growth from low-temperature solutions - theory and experiments
Novotný, Jan
Growth of crystals from low-temperature solutions belong to extended methods to acquire of high quality single crystals. Presented work reports the basic theories of crystal growth from solutions and shows their applications to optimization of crystal qrowth conditions where goal is preparation of high quality of single crystals. Next are shown experimental results of preparation of optical non-linear crystals for optoelectronics obtained at crystal growth laboratory of IREE AS CR.
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Sustainable tourism development of Vysocina Region
Veselá, Markéta ; Macháček, Jaroslav (advisor) ; Vondráková, Zuzana (referee)
The diploma thesis deals with the topic of sustainable tourism development at the regional level. This phenomenon is elaborated on the example of Vysocina Region. To evaluate sustainability of its development, the potential of this touristic destination is researched regarding various areas, including key products. These are subjected to comparisons with recommendations of significant tourism organization for the purpose of assessing the sustainability of tourism. The diploma thesis also includes a comparison with other Czech regions experience as a touristic destination. Vysocina Region has favourable initial conditions for its sustainable development, especially regarding supply of key products, which include both environmentally friendly goods and cultural attractiveness contributing to the personal development of individuals and promoting intercultural tolerance. The main issue appears to be the spatial imbalance of its development in the region, caused mainly by the concentration of tourist activities to certain areas and low local initiative in the less attractive areas. The diploma thesis proposes a number of solutions, such as utilization of geocaching and products of gastroturism, supporting the foundation of local destination management organisations, promoting cycling tourism and the foundation of highly visited tourist destinations.
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Internal Migration in PRC: function, role and impact on Chinese economy
Čermáková, Zuzana ; Stuchlíková, Zuzana (advisor) ; Procházková Ilinitchi, Cristina (referee)
The purpose of this thesis is to analyze the process of internal migration in Peoples' Republic of China. It focuses on low-skilled rural migrant workers, their overall characteristics, role in the economy and their status within Chinese society. This analysis aims to prove that despite the fact that rural migrants represent an essential element of Chinese economy, and have contributed by a great deal to China's economic take-off, they are still a very discriminated group of Chinese society and are constantly facing violations of their rights.
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Impact of low oil and natural gas prices on the economy of Qatar since 2014
Šamánek, Ondřej ; Stuchlíková, Zuzana (advisor) ; Hasík, Gabriel (referee)
The bachelor thesis examines the impact of the oil and gas prices slump, which befell the world in 2014, on the economy of Qatar. The main objective of the thesis is to evaluate if and to what extend the price collapse influenced the relevant economic indicators and behaviour of the state and companies active in the affected field. The selected objective is examined using the method of data comparison, namely before and after the price slump, and with the help of the case study, in which the qatari company operating in the oil and gas is examined. From the conducted analysis it is possible to conclude that Qatar was directly influenced by the oil and gas prices collapse: its GDP slumped, fiscal deficit increased. The analysed company also experienced troubles caused by low prices: one year after the price slump, total amount of assigned tenders to company decreased substantially and historically high number of tenders was cancelled. Conclusions deriving from the thesis might be applied to other oil and gas export economies in the Persian Gulf, for fundamental traits of such economies are shared with the economy of Qatar.
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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
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Lifelong Education as a Part of the Social System
Neckařová, Jana ; Šrédl, Karel (advisor) ; Hana, Hana (referee)
The diploma thesis discusses about education of adult population, while pointing out necessity of education in any age. This thesis explain importance of education of the adult population, mention forms and possible methods which are used in this type of education the most. Besides the theoretical outcome there is practical aspect included as well in form of questionnaires. Investigation in form of research was focused directly on employees, who as well as on employers whose employees attended the program. In summary both parties consider adulthood gained knowledge as a great benefit to employee as well as employer. In any case, people with higher level of education have better chances of getting a possible job than those with no or low level of education.
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Freezing technology of bull sperm in relation to its survivability and fertilization ability
Doležalová, Martina ; Stádník, Luděk (advisor) ; Jiří, Jiří (referee)
The aim of optimalization the insemination doses production is to provide the highest fertilization ability of spermatozoa during the demanding proces of processing fresh semen and its subsequent cryopreservation. Temperature changes causes spermatozoa damage during the cooling and freezing. Spermatozoa is exposed to cold shock and many others limiting factors, which leads to cell death and therefore to decline of fertilization ability of thawed insemination doses. For increasing spermatozoa resistance, exactly the plasma membrane resistance against cold shock was fraction of egg yolk LDL cholesterol (low density lipoprotein) at various concentrations into the comercially produced diluents added. It is believed that LDL acts possitively to plasma membrane and helps to maintain the fertilization ability of spermatozoa after thawing. Following step in the proces of insemination doses production is slow cooling of diluted semen and equilibration, when the straws are store at cooling box for 30 minutes to 240 hours. This period is necessary to penetrate of certain diluent components into the spermatazoa also maintain the balance between their intracellular and extracellular concentration. Also important is subsequent freezing temperature gradient of insemination doses. The most suitable freezing method is based on computer controlled temperature decline in freezing chamber which allows the precise control of ice crystals formation that could tear and kill the cell.
During 2012 to 2016 was repeatedly collected semen from the group of breeding bulls (n = 27, Holstein and Czech Fleckvieh breed) at AI centre. Semen which fulfill the standard entrance conditions in first step was evenly into several parts divided. For dilution the three types of comercially diluents AndroMed, Bioxcell and Triladyl with and without LDL addition were used. Into the diluents AndroMed and Bioxcell the concentration of LDL 4 %, 6 % and 8% into the dilent Triladyl 6 %, 8 % and 10 % was added. Diluted semen was filled into the glass capillares with volume 0,1 ml and temperature +4 °C. Subsequently the sample was placed to cold bath (0°C) for 10 minutes. Then the volume of capillare with physiological solution (37 °C) was mixed and for next 120 minutes was incubate. The effect of cold shock to proportion of live spermatozoa was evaluated by using Eosin and Nigrosine staining technique during heat test of spermatozoa survivability after spermatozoa heating and after 120 minutes of incubation.
The more suitable semen diluents which provide the higher spermatozoa resistance against cold shock were AndroMed and Bioxcell. Together the possitive effect of LDL addition into the diluents to lower decrease of proportion of live spermatozoa during heat test was found (P<0.05). The most suitable LDL concentration which had a favorable influence at spermatozoa resistance against cold shock was 6 % in diluent Bioxcell. Values of the proportion of live sperm were higher at the beginning of the heat test (+1.31% to + 3.2%) and after 120 minute incubation (+5.82% to +8.41%) compared to other diluents with and without addition of LDL.
In the next step the process of equilibration was optimized, is an important part of insemination doses production. The effect of the length of equilibration for subsequent fertilization ability of spermatozoa was evaluated using spermatozoa motility based of CASA and proportion of live spermatozoa after thawing and during heat survival test lasting 120 minutes (37 ° C). Suitable semen was diluted by comercially used diluent AndroMed based on soya lecithin, filled into the straws (0.25 ml), cooled and equilibrated in cooling box for 30, 120 and 240 minutes and freezed in programmable freezing box applying four types of freezing curves differing in temperature rate decline. There was used standard and by producer recommended 3. phase freezing curve, then 2. phase freezing curve, and 3. phase freezing curve with slower as well as rapid decline of temperature rate in freezing chamber, compared with standard freezing curve. The highest spermatozoa motility was found using 240 minutes of equilibration by +2.72% and +4.58% compared to other lengths of equilibration (P <0.05 to 0.01). The highest proportion of live spermatozoa was found using 120 minutes of equilibration (+6.87 % and +8.68 %). The highest average spermatozoa motility during heat test after thawing was achieved by using 2. phase freezing curve (from +2.97% to +10.37%, P <0.05), also in the proportion of live spermatozoa (from + 4.37% to +8.82%, P <0.01). When evaluating interaction between the length of equilibration and freezing curve (standard 3. phase and 2 . phase freezing curve), the highest average spermatozoa motility and proportion of live spermatozoa using 240 minutes of equilibration by both freezing curves was reached, there was no statistically significant differences. As well as, in all evaluated parts of this study the individual differences between ejaculate of bulls and within semen from one bull (P <0.05) as secondary effect were found.
To maintain good fertilization ability of semen during cryopreservation is necessary to increase the spermatozoa resistance against cold shock using addition of correct concentration of LDL into the commercially used diluents AndroMed and Bioxcell. Subsequently the fertilization ability of insemination dose is influenced by cooling, the length of equilibration and freezing. The length of equilibration 120 minutes and more as well as gentle way of freezing according to freezing curve, which ensures a gradual decrease of temperature in freezing chamber provided the higher average spermatozoa motility and proportion of live spermatozoa.
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Total contents and speciation of arsenic and selenium in plants growing in soils with different physico-chemical properties
Tremlová, Jana ; Száková, Jiřina (advisor) ; Vymazal, Jan (referee)
This dissertation thesis deals with uptake, accumulation and transformation of arsenic and selenium in plants growing on soils with different chemico-physical soil properties. The contents of arsenic were investigated in 99 wild plant species, coming from 27 different families and 6 different vegetables growing in arsenic contaminated soils. The results suggest that there are species-specific mechanisms which protects certain plants from the excessive uptake of arsenic from the soil. On the other hand, there are plants using a strategy of accumulation, which theoretically may increase the risk of arsenic entry into the food chain, whether through grazing cattle and wildlife or through consumption of vegetables growing on arsenic contaminated soils. The most prevalent arsenic compounds are AsV and AsIII. Other arsenic compounds occure as minor species. An important finding was detection of arsenobetaine in Plantago lanceolata L. and Carex praecox Schreb ..
The contents of selenium were examined in 73 species of wild plants, coming from 29 different families. The results suggest that naturally low levels of selenium in the soil of selected locations along with a low capability of selenium uptake via collected plant species lead to the low content of selenium in plant biomass which may contribute to selenium deficient throughout the food chain. Foliar application of selenate on wild plant communities and on some types of vegetables in our case Brassica oleracea var. italica can have a positive impact on increasing the selenium content in the aboveground biomass of these plants and by extension, increase the selenium content in the human diet. Dominant selenium compounds in the aboveground biomass of the analyzed plants were SeVI and selenomethionine, with variable proportion of other commonly occurring organic selenium compounds, which is mainly affected by plant species.
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Confidence Cycles and Liquidity Hoarding
Audzei, Volha
Market confidence has proved to be an important factor during past crises. However, many existing general equilibrium models do not account for agents’ expectations, market volatility, or overly pessimistic investor forecasts. In this paper, we incorporate a model of the interbank market into a DSGE model, with the interbank market rate and the volume of lending depending on market confidence and the perception of counterparty risk. In our model, a credit crunch occurs if the perception of counterparty risk increases. Our results suggest that changes in market confidence can generate credit crunches and contribute to the depth of recessions. We then conduct an exercise to mimic some central bank policies: targeted and untargeted liquidity provision, and reduction of the policy rate. Our results indicate that policy actions have a limited effect on the supply of credit if they fail to influence agents’ expectations. Interestingly, a policy of a low policy rate worsens recessions due to its negative impact on banks’ revenues. Liquidity provision stimulates credit slightly, but its efficiency is undermined by liquidity hoarding.
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Automatic system for gauge blocks calibration optimized for legal length metrology
Buchta, Zdeněk ; Šarbort, Martin ; Čížek, Martin ; Hucl, Václav ; Řeřucha, Šimon ; Pikálek, Tomáš ; Dvořáčková, Š. ; Dvořáček, F. ; Kůr, J. ; Konečný, P. ; Lazar, Josef ; Číp, Ondřej
This paper presents a contactless system for automatic and contactless gauge blocks calibration based on combination of laser interferometry and low-coherence interferometry. In the presented system, the contactless measurement of the absolute gauge block length is done as a single-step operation without any change in optical setup during the measurement. The optical setup is combined with compact gauge block changer with capacity 126 gauge blocks, which makes the resulting system fully automatic. \nThe paper also presents in detail a set of optimization steps which have been done in order to transform the original experimental setup into the automatic system which meets legal length metrology requirements. To prove the measurement traceability, we conducted a set of gauge block length measurement comparing data from the optimized system and the established reference system and TESA–UPC operated in Czech Metrology Institute laboratory.
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