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AN INTERPLAY BETWEEN HEAT TREATMENT CONDITIONS AND B2 <-> B19 ' TRANSFORMATION IN Ni-Ti SHAPE MEMORY ALLOYS
Kuběnová, Monika ; Zálešák, Jakub ; Čermák, Jiří ; Dlouhý, Antonín
This study investigates the influence of a heat treatment atmosphere on multistage martensitic transformations in a Ti-50.9at% Ni shape memory alloy. Evacuated quartz tubes were filled with hydrogen while the hydrogen partial pressure was carefully controlled in each experiment. The encapsulated specimens were subjected to heat treatments consisting of annealing and aging. After the heat treatment, the path of martensitic transformation was investigated using differential scanning calorimetry (DSC). On cooling, martensite initial temperatures decrease with the increasing partial pressure of hydrogen applied during the heat treatment. Moreover, the formation of martensite phase may not take place for partial pressures that exceed a certain limit. On the other hand, two-and multiple-step B2/R/B19' martensitic transformations are observed in specimens heat treated at lower hydrogen pressures. Results obtained using transmission electron microscopy (TEM) clearly show that the size of Ni4Ti3 precipitates becomes smaller in alloys that were heat treated at higher hydrogen pressures. The results are discussed in terms of a chain of events. It is suggested that diffusion of hydrogen into the specimen during the annealing step first influences the nucleation of the Ni4Ti3 phase. The sizes and distribution of the Ni4Ti3 precipitates than control the characteristics of B2/B19' transformation.
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HYDROGENATION OF CHOSEN MgMXN INTERMETALLICS (X=Al, Ga, In, Si, Sn)
Čermák, Jiří ; Král, Lubomír ; Roupcová, Pavla
Hydrogen sorption in chosen intermetallics MgmXn (Mg17Al12 , Mg2Ga, mixture of beta-Mg-In phases, Mg2Si and Mg2Sn) formed by magnesium and elements from the 13 th (X: Al, Ga, In) and 14 th (X: Si, Sn) groups was studied between the room temperature and T = 350 °C. Hydrogen pressure p varied from 10-3 MPa to 6 MPa.\nHydrogen solubility in alpha phase (solid solution of hydrogen in MgmXn before the hydride phase was nucleated) was close to hydrogen solubility in pure Mg. Concentration cH of hydrogen solved in Mg m X n depended linearly on pressure p , dependence of cH on temperature T was relatively weak. MgH2 was the main hydrogen storage phase in all the compounds MgmXn . Nucleation of MgH2 at 350 °C was observed at pressure above approximately 1 MPa in Mg17Al12 and above 2 Ma in other compounds. Maximum values of c H in hydride-containing compounds MgmXn detected at T = 350 °C depended on the stability of MgmXn .
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HYDROGENATION PROPERTIES OF Mg-Al-Ti-Zr-C COMPOSITE
Král, Lubomír ; Čermák, Jiří ; Roupcová, Pavla
The improvement of hydrogen storage properties of ball-milled Mg-Al-Ti-Zr-C composite was studied in this\npaper. It has been previously shown, that the addition of Ti, Zr, Al and C improves storage properties of Mg.\nThis beneficial effect of additives upon hydrogen storage properties can be explained by catalysis by the\nnanoparticles rich in Ti, Zr or Al located on the surface of Mg grains. They provide effective pathways for the\nhydrogen diffusion into the MgH2. The morphological and microstructural characteristics were investigated by\nscanning electron microscope Tescan Lyra 3 and by X-ray diffraction. The hydrogen sorption was measured\nby Sieverts method using Setaram PCT-Pro device.\nStudied experimental composite absorbed 4.2 wt.% H 2 at 573 K and 3 wt.% H 2 at 523K within 10 min. The\nhydrogen storage capacity of the composite was about 4.6% wt.% H 2 and 4.2% wt.% H 2 at 573K and 523K,\nrespectively.
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Bioinformatics Tool for Prediction of Protein Solubility
Čermák, Jiří ; Hon, Jiří (referee) ; Martínek, Tomáš (advisor)
To achieve cheaper and more efficient protein production, we must be able to predict protein solubility. In this thesis, we describe creation of bioinformatic data sets based on Target Track and eSol databases, we test the features used in existing protein solubility prediction tools and create a new predictor. Even though we fail to create an effective prediction tool we find out that in most cases the old features tested on the new data do not correlate with protein solubility as strongly as others repot in older and smaller datasets.
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Security and safety at Football Stadiums
Pail, Čestmír ; Janák, Vladimír (advisor) ; Čermák, Jiří (referee)
SECURITY AND SAFETY ON FOOTBALL STADIUMS This thesis deals with the safety of the Czech firstleague stadiums. The theoretical part describes how security was ensured in the history of Czech Football League and also defines main manifestations o hooliganism during matches in this league. It also includes faces of agression of football fan. The main purpose of this thesis is to describe the organization of safety and security in Czech football today. Especially it tries to determine a suitable model according to which one could achieve sufficient security of football matches in the most effective and appropriate manner. Keywords: Security, Football, Stadium, Violence and Agression, Audience
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Baltic States: Lessons from the Crisis
Čermák, Jiří ; Holub, Tomáš (advisor) ; Herrmannová, Lenka (referee)
Between 2000 -2007 Baltic countries were among the fastest growing economies in Europe, but in 2008 they were struck by very deep recession. Unlike the other Central and Eastern European countries, the Baltics maintained fixed exchange rate regimes and it raised the question about their effects on the economies. This work focuses on the external imbalances of the Baltic economies. It analyzes the compositions and sources of the current account deficits and discusses other influential factors. Detailed discussion is devoted to the capital inflows and their determinants. The thesis also contains empirical study which analyzes the relationship between the exchange rate regime and current account balance. We find that the current account deficits were not sustainable not only because of their sizes but also for their structure. The empirical analysis of the relationship between exchange rate regimes and current account deficits did not bring clear - cut results which would prove the hypothesis that the fixed exchange regimes negatively affect the current account balances. 1
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Proposal of electrical equipment for soaking and drying cores for making castings
Čermák, Jiří ; Hájek, Vítězslav (referee) ; Veselka, František (advisor)
This diploma thesis deals with proposal of electrical equipment for soaking and drying cores for making castings at foundry in a Great Britain. It brings look at system of technical norms ČSN and it compares it with british system of technical norms British standards. The second part of this thesis contains detailed proposal of this equipment, including specification of control system, specification of power supply cables and control cables and particular technological units. The whole project documentation is enclosed as an inseparable attachment of this diploma thesis.
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Offer of sport services in health resorts of Czech Republic
Pail, Čestmír ; Voráček, Josef (advisor) ; Čermák, Jiří (referee)
OFFER OF SPORT SERVICES IN HEALTH RESORTS OF CZECH REPUBLIC This work is describing spas and spa services in the Czech Republic. It is describing emergence of spa industry in our country as same as in the rest of the world. It is explaining the process of spa healthcare, which services are, and which are not included in donated care in the Czech Republic. It is mainly focusing on sports services and the offer of sports in spa resorts Poděbrady and Mariánské Lázně. Using SWOT Analysis, it is trying to find strengths, weaknesses, opportunities and threats in relation to these resorts. This work is trying to find importance of sport and the proportion of sport services in compare to all spa services. It is also trying to point on possibilities of development of sport services in spa resorts Poděbrady and Mariánské Lázně. Finally it is recommending that the offer of sport activities in spa resorts Poděbrady and Mariánské Lázně should expand to reach higher level of quality of Czech spa industry at all. Keywords: Balneology, services, wellness, sport
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