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Mpembe effect - reality or fiction? (Hysteresis by water freezing).
Böhm, Pavel ; Obdržálek, Jan (advisor) ; Rotter, Miloš (referee)
The aim of this thesis was to review theoretically and experimentally so-called Mpemba eect, where the initially hot water freezes sooner than the initially cold one. Based upon already published theoretical and experimental works, a list of circumstances possibly supporting this phenomenon was created and discussed. Some situations were veried experimentally. These experiments were carried out partly in laboratory using small amounts of distilled water (less than 1 ml), partly in "kitchen conditions" using the tap water (about 200 ml) and a commercial home refrigerator. The time of freezing dened by freezing of the entire body of water was measured using the inection points of cooling curves. Unlikely to the Mpemba eect (and likely to the usual expectations), usually the sample of cold water freezes sooner than the hot one. The Mpemba eect occured rarely, mostly when the cooler was covered by the layer of the snow and the hot vessel could melt through it to reach better thermal contact than the cold vessel. Other observed cases were mostly inconclusive.
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Volatility of Euro: Trends and Modelling
Böhm, Petr ; Hanousek, Jan (referee) ; Kočenda, Evžen (advisor)
The main objective of this work is to model volatility of Euro to Czech Koruna exchange rate between 1.1.1999 and 30.12.2005 and investigate changes in its behaviour. In order to achieve this we search for structural breaks in exchange rate time series. We model the conditional variance with ARCH model (autoregressive conditional heteroscedasticity) between particular break points. Our findings are that since year 2002 volatility of Euro to Koruna exchange rate has been decreasing. This conclusion is confirmed by measuring historic volatility by using month average and daily observations. This may has been caused by changing monetary policy, more precisely by adopting new regime of maintaining monetary stability - implicit inflation targeting.
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Use of brownfields as a part of potential in rural areas
BÖHM, Petr
This thesis deals with the definitions of rural development, rural areas, brownfields, greenfields. In the practical part compares two real locations in South County. Greenfield site is located in the village in the district Vidov Czech Budejovice and borwnfield site is located in the village in the district Želeč Tabor. Both locations are assessed according to the model of South Bohemia, which is based on studies němcekého Ministry of Environment. This model consists zetří criteria - potential sites in terms of community benefit in terms of potential investor and the change in the value space - public interest in the regeneration of brownfield sites. These three criteria are still my sub, under which then determines the significance of the site. Then, by calculating the preference index (PI) to determine which location is more suitable for implementation.
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Data Acquisition System and Data Processing for the New Thomson Scattering System on the COMPASS Tokamak
Aftanas, Milan ; Bílková, Petra ; Böhm, Petr ; Weinzettl, Vladimír ; Stöckel, Jan ; Hron, Martin ; Pánek, Radomír ; Scannell, R. ; Walsh, M.
The Thomson scattering (TS) will be one of crucial plasma diagnostics of the COMPASS tokamak. This newly build-up multi-point system consists of two Nd:YAG lasers (1.6J at 1064nm, 30Hz each) and cascade filter polychromators with avalanche photodiodes. It will enable measurements of both the electron temperature Te (20eV − 5000eV ) and density ne (1019 − 1020m−3) profiles with spatial resolution up to 3mm in the vertical direction in 56 spatial points. The uniquely designed complex data acquisition system based on fast analog digital convertors (1GS/s) reflects the need to retrieve/digitize the signal originated from scattering process of the laser pulse lasting less than 10ns. This paper presents a detailed review of the architecture of the control and the data acquisition (DAQ) system and its features. LabViewr will be used as a main layer for the TS data acquisition. Routines specifically written for controlling the DAQ of TS on COMPASS are presented.
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Measurement of the Laser Beam Position and Width for the Thomson Scattering Diagnostics on Tokamak COMPASS
Aftanas, Milan ; Bílková, Petra ; Böhm, Petr ; Weinzettl, Vladimír ; Stöckel, Jan ; Hron, Martin ; Pánek, Radomír
COMPASS tokamak is equipped with new key diagnostic—Thomson scattering system. This unique multi-point system has been designed with the main aim to investigate electron density and temperature profiles on the COMPASS tokamak (R = 0.56 m, a = 0.18 m, BT max = 2.1 T). The spatial resolution is optimized namely for the pedestal studies (radial spatial resolution a/100). This contribution describes particular steps of optical alignment of the important part of the Thomson scattering system, Nd:YAG lasers (1.6 J at 1064 nm, 30 Hz). Laser beam width has to be precisely measured and laser beam position has to be precisely set before the measurement and checked for all laser shots to be able of decrypting the information about the plasma density and also to improve precision of the measurement. New tool for automatic measurement of the laser beam misalignment is introduced.
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Blackout and Its Impact on the Emergency Medical Service
BÖHM, Pavel
At present, due to the use of different technologies, it is hard to think of any human activity that does not demand electric power. It is necessary to be prepared for of large-scale long-term blackouts. Possible scenarios of the occurrence of such a crisis situation must be analyzed and the crisis management must be prepared; primarily to minimize the impact on the lives and health of the population, their property and also natural environment. The objective of the thesis was to identify the operational readiness of regional centers of Emergency Medical Services in the Czech Republic for the possibility of blackouts and to create a survey of power supply possibilities to the operating center of the Emergency Medical Services. The questionnaire was focused on the analysis of operational readiness of regional centers for total blackout, on the framework of their technical support in alternative energy production and its time sustainability. The documents analysis included a pattern plan of the Ministry of Trade and Industry of the Czech Republic and an operational plan for the occurrence of a crisis situation - large-scale electric power supply disturbances, and other internal regional documents concerning the situation during a blackout. The outcomes of the thesis can be used as a background material for the comparison of emergency blackout preparedness in international environment. They can be used to achieve certain standards in the field of sustainable alternative energy supply of Emergency Medical Services centers.
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Ability of University Students to Administer First Aid
BÖHM, Pavel
Life is the most valuable possession of a man. Any of us can find himself in a situation, when we will have to provide first aid to an injured person. The objective of this paper was to survey what practical knowledge of administering not professional first aid the university students have. A qualitative research in the form of a case study was applied, with help of the observation method and polling method - an interview with open questions. The results of this paper were presented at a scientific conference called: "Rescue workers to each other, or let us do not preach at each other, but learn from each other", in Hrubá Voda, on 26th March, 2009. A crucial point of this research was to survey the abilities of not professionals to provide first aid some time after their training. These results might be used for making up and setting curricula and educational methods in the field of didactics of urgent medical assistance.
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Models and methods for network economies
BÖHM, Petr
The goal is to create a summary of models and methods for network economies including network structure, a dynamic and uncertain environment, factors more criteria in the network economy. Deeper deal with graph theory, networks and supply networks. Part of this work is the analytical part, where the patterns and using them I find the position of nodes in the network data from Lidé.cz and eBay. I demonstrate the models and calculations.
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The Progress of Muscular Dysbalances by University Students
BÖHM, Pavel
This bachelor work was aimed at the progress of muscular dysbalances by university students. The aim of the thesis was to survey a rough structured profile of weekly physical activities of a university student and determine the most critical motoric activities leading to the muscle imbalance development. To achieve the objectives quantitative research was used. The case study technique was applied when the person observed took a record of his physical activities during a twenty-four hour period on a work day.
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