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Transmutation of spent nuclear fuel with using accelerator driven systems
Máca, Pavel ; Král, Dušan (referee) ; Zeman, Miroslav (advisor)
This bachelor thesis deals with the analysis of neutron spectra in the reactors with liquid salts. The teoretical part contains a brief description of the nuclear fuel cycles. In the theoretical are further described the reactors of IV. generations. Here are the reactors on the basis of liquid salts described in detail. The practical part of the bachelor thesis is focused on the analysis of neutron spectra in set-ups performer from solid salt. Concretly, the salts NaCl and KCl were analysed by means of the computational codes TALYS and MCNP.
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Methodology for rapid, comprehensive, independent decision-making on the need, effectiveness and interaction of adaptation measures in river basins under climate change
Fischer, Milan ; Zeman, Evžen ; Vizina, A. ; Hanel, M. ; Bernsteinová, Jana ; Tachecí, P. ; Štěpánek, Petr ; Pavlík, P. ; Máca, P. ; Ghisi, Tomáš ; Rapantová, N. ; Bláhová, Monika ; Janál, P. ; Trnka, Miroslav
The aim of the methodology is to present methods for quantifying the impacts of projected climate change on the water balance when applying adaptation measures in the Czech Republic for the next few decades. Adaptation measures should contribute to the sustainability of the water balance in all major user segments of water use and management in the basin. The main principle is the use of hydrological models to transform climate change scenarios into time series of hydrological conditions and to quantify the overall water balance of the basin using different types of adaptation measures and their implementation over time. Special emphasis is placed on the evaluation of combinations of adaptation measures that cannot be analysed by simplified methods. The methodology is designed to search for the optimal combination of adaptation measures in the assessed catchment. The proposed approach eliminates the shortcomings of effectiveness assessment from the perspective of the exclusive user of the water resource, as the evaluation of the effectiveness of adaptation measures is carried out in the form of a multi-criteria analysis of the evaluation of the outputs of the simulation model for predicting the water balance in the whole basin. This methodology can be used to assess different adaptation measures in all basic segments of water users: agriculture, forestry, energy, water management and others.
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Methodology for determining the main disturbances in the water management balance and optimizing adaptation measures in the conditions climate change
Fischer, Milan ; Zeman, Evžen ; Vizina, A. ; Hanel, M. ; Bernsteinová, Jana ; Tachecí, P. ; Štěpánek, Petr ; Pavlík, P. ; Máca, P. ; Ghisi, Tomáš ; Rapantová, N. ; Bláhová, Monika ; Janál, P. ; Trnka, Miroslav
Ongoing climate change is causing a global increase in air temperature. While this is leading to an acceleration of the global hydrological cycle, and therefore a global increase in precipitation, the spatiotemporal variability in precipitation is much more complicated. While temperature in the Czech Republic shows a consistently increasing trend similar to that of surrounding countries and the planet as a whole, precipitation can be simplified that long-term averages of annual totals remain and are likely to remain very similar in the coming decades. Rising air temperatures inherently bring increased evaporative demand of the atmosphere and, for the same precipitation, a lower ratio of precipitation to evaporation, i.e. the climatic water balance shows a negative trend.
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Computation analysis of the VVER-440 nuclear power reactor core
Máca, Pavel ; Šnajdárek, Ladislav (referee) ; Katovský, Karel (advisor)
This thesis is focused on effect of fuel assembly rotation on the reactor core optimization in VVER-440 reactor. In the first part of this thesis, a brief description and main parameters of VVER-440 reactor are introduced. Next chapter is focused on the Dukovany NPP reactor core design, where these reactors are in operation, together with evolution of used fuel assemblies and reactor core design optimization. The practical part of this thesis includes a comparison of reactor core design optimization with and without fuel assemblies‘ rotation. Furthermore, a so-called multiple rotation method is investigated, which could be more suitable compared to the currently used one.
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Transmutation of spent nuclear fuel with using accelerator driven systems
Máca, Pavel ; Král, Dušan (referee) ; Zeman, Miroslav (advisor)
This bachelor thesis deals with the analysis of neutron spectra in the reactors with liquid salts. The teoretical part contains a brief description of the nuclear fuel cycles. In the theoretical are further described the reactors of IV. generations. Here are the reactors on the basis of liquid salts described in detail. The practical part of the bachelor thesis is focused on the analysis of neutron spectra in set-ups performer from solid salt. Concretly, the salts NaCl and KCl were analysed by means of the computational codes TALYS and MCNP.
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SDK v PHP pro API v otevřeném bankovnictví
MÁCA, Pavel
This bachelor's thesis focuses on the creation of a library in PHP language for the API specified by czech standard for the Open banking. First part is targeted to analyse the czech standard in conjunction with the european Payment Service Directive, known as the PSD2. Next part describe requirements of the libraly for consuming REST API. Practical part contains creation of the library and it's usage. This library is designed for use in a financial application and managing user financial informataion and payments.
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Analysis of runoff in selected urban watershed
Kučera, Vít ; Máca, Petr (advisor) ; Petr, Petr (referee)
The work deals with schematization area with sewage networks in the Rainfalls-runoff model urbanized watershed modeling and changes in the Manning roughness coefficient of the pipe to the main sewer, which drains most of the wastewater. The comparison was made on two schematization basin Bohnice collector the main sewer F in the city. Prague. For the simulation program was used Mike URBAN DHI Inc.
The main variable was observed outflow hydrograph on the selected sealing profile watershed and its development depending on schematization and change the Manning roughness coefficient.
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Effect of snowpack on runoff generation during rain on snow event.
Juras, Roman ; Máca, Petr (advisor) ; Ladislav , Ladislav (referee)
During a winter season, when snow covers the watershed, the frequency of rain-on-snow (ROS) events is still raising. ROS can cause severe natural hazards like floods or wet avalanches. Prediction of ROS effects is linked to better understanding of snowpack runoff dynamics and its composition. Deploying rainfall simulation together with hydrological tracers was tested as a convenient tool for this purpose. Overall 18 sprinkling experiments were conducted on snow featuring different initial conditions in mountainous regions over middle and western Europe.
Dye tracer brilliant blue (FCF) was used for flow regime determination, because it enables to visualise preferential paths and layers interface. Snowpack runoff composition was assessed by hydrograph separation method, which provided appropriate results with acceptable uncertainty. It was not possible to use concurrently these two techniques because of technical reasons, however it would extend our gained knowledge. Snowmelt water amount in the snowpack runoff was estimated by energy balance (EB) equation, which is very efficient but quality inputs demanding. This was also the reason, why EB was deployed within only single experiment.
Timing of snowpack runoff onset decrease mainly with the rain intensity. Initial snowpack properties like bulk density or wetness are less important for time of runoff generation compared to the rain intensity. On the other het when same rain intensity was applied, non-ripe snowpack featuring less bulk density created runoff faster than the ripe snowpack featuring higher bulk density. Snowpack runoff magnitude mainly depends on the snowpack initial saturation. Ripe snowpack with higher saturation enabled to generate higher cumulative runoff where contributed by max 50 %. In contrary, rainwater travelled through the non-ripe snowpack relatively fast and contributed runoff by approx. 80 %.
Runoff prediction was tested by deploying Richards equation included in SNOWPACK model. The model was modified using a dual-domain approach to better simulate snowpack runoff under preferential flow conditions. Presented approach demonstrated an improvement in all simulated aspects compared to the more traditional method when only matrix flow is considered.
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Application of optimization methods in hydrological modeling
Jakubcová, Michala ; Máca, Petr (advisor) ; Hanel, Martin (referee)
Finding the optimal state of reality is the main purpose of the optimization process. The best variant from many possibilities is selected, and the effectiveness of the given system increases. Optimization has been applied in many real life engineering problems as in hydrological modelling. Within the hydrological case studies, the optimization process serves to estimate the best set of model parameters, or to train model weights in artificial neural networks.
Particle swarm optimization (PSO) is relatively recent optimization technique, which has only a few parameters to adjust, and is easy to implement to the selected problem. The original algorithm was modified by many authors. They
focused on changing the initialization of particles in the swarm, updating the population topology, adding new parameters into the equation, or incorporating shuffling mechanism into the algorithm.
The modifications of PSO algorithm improve the performance of the optimization, prevent the premature convergence, and decrease computation time. Therefore, the main aims of the presented doctoral thesis consist of proposal of a new PSO modification with its implementation in C++ programming language. More PSO variants were compared and analysed, and the best methods based on benchmark problems were applied in two hydrological case studies.
The first case study focused on utilization of PSO algorithms in inverse problem related to estimation of parameters of rainfall-runoff model Bilan. In the second case study, combination of artificial neural networks with PSO methods was introduced for forecasting the Standardized precipitation evapotranspiration drought index.
It was found out, that particle swarm optimization is a suitable tool for solving problems in hydrological modelling. The most effective PSO modifications are the one with adaptive version of parameter of inertia weight, which updates the velocity of particles during searching through the multidimensional space via feedback information. The shuffling mechanism and redistribution of particles into complexes, at which the PSO runs separately, also significantly improve the performance.
The contribution of this doctoral thesis lies in creation of new PSO modification, which was tested on benchmark problems, and was successfully applied in two hydrological case studies. The results of this thesis also extended the utilization of PSO methods in real life engineering optimization problems. All analysed PSO algorithms are available for later use within other research projects.
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Using Weather Generators for the Assessment of the Impact of Climate Change in Catchments
Martínková, Marta ; Hanel, Martin (advisor) ; Máca, Petr (referee)
The main objective of this dissertation is to provide a novel approach to downscaling of outputs from regional climate models and to simulation of future climate. The resulting method consists of rain generator that operates in 6-hour time step. The generator performs well for the observational data.
It consists of following steps: disaggregation of 6-hour cumulative precipitation into convective and stratiform types, fitting of first order 3-state discrete time Markov chain to the data and simulation of long time series of precipitation. Then the mixture of log-normal and Generalized Pareto distribution is fitted to stratiform events and the Generalized extreme value distribution is fitted to convective events.
The impact of climate change on precipitation is evaluated by using change factors that are identified for precipitation occurrence (by comparing the transition matrices for the future and control period) and for precipitation amount (by comparing the scale and location parameters of distributions fitted for the future and control period). The observational data are then altered with obtained change factors.
From evaluation of observational data it stems that the average volume of an convective event is higher for the western region than for eastern region of the Czech Republic. Additionally, statistically significant trends in number and volume of convective events were identified for the region.
The relative portion of convective precipitation is the highest in summer for observational data.
From analysis of RCMs simulations, it stems that even though the overall precipitation is projected to be lower in future, the proportion of convective events (versus stratiform ones) would be higher. The number of convective events is projected to be lower in the future, while the volume of a convective event to be bigger.
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