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Modelling, parameter estimation, optimisation and control of transport and reaction processes in bioreactors.
ŠTUMBAUER, Václav
With the significant potential of microalgae as a major biofuel source of the future, a considerable scientific attention is attracted towards the field of biotechnology and bioprocess engineering. Nevertheless the current photobioreactor (PBR) design methods are still too empirical. With this work I would like to promote the idea of designing a production system, such as a PBR, completely \emph{in silico}, thus allowing for the in silico optimization and optimal control determination. The thesis deals with the PBR modeling and simulation. It addresses two crucial issues in the current state-of-the-art PBR modeling. The first issue relevant to the deficiency of the currently available models - the incorrect or insufficient treatment of either the transport process modeling, the reaction modeling or the coupling between these two models. A correct treatment of both the transport and the reaction phenomena is proposed in the thesis - in the form of a unified modeling framework consisting of three interconnected parts - (i) the state system, (ii) the fluid-dynamic model and (iii) optimal control determination. The proposed model structure allows prediction of the PBR performance with respect to the modelled PBR size, geometry, operating conditions or a particular microalgae strain. The proposed unified modeling approach is applied to the case of the Couette-Taylor photobioreactor (CTBR) where it is used for the optimal control solution. The PBR represents a complex multiscale problem and especially in the case of the production scale systems, the associated computational costs are paramount. This is the second crucial issue addressed in the thesis. With respect to the computational complexity, the fluid dynamics simulation is the most costly part of the PBR simulation. To model the fluid flow with the classical CFD (Computational Fluid Dynamics) methods inside a production scale PBR leads to an enormous grid size. This usually requires a parallel implementation of the solver but in the parallelization of the classical methods lies another relevant issue - that of the amount of data the individual nodes must interchange with each other. The thesis addresses the performance relevant issues by proposing and evaluation alternative approaches to the fluid flow simulation. These approaches are more suitable to the parallel implementation than the classical methods because of their rather local character in comparison to the classical methods - namely the Lattice Boltzmann Method (LBM) for fluid flow, which is the primary focus of the thesis in this regard and alternatively also the discrete random walk based method (DRW). As the outcome of the thesis I have developed and validated a new Lagrangian general modeling approach to the transport and reaction processes in PBR - a framework based on the Lattice Boltzmann method (LBM) and the model of the Photosynthetic Factory (PSF) that models correctly the transport and reaction processes and their coupling. Further I have implemented a software prototype based on the proposed modeling approach and validated this prototype on the case of the Coutte-Taylor PBR. I have also demonstrated that the modeling approach has a significant potential from the computational costs point of view by implementing and validating the software prototype on the parallel architecture of CUDA (Compute Unified Device Architecture). The current parallel implementation is approximately 20 times faster than the unparallized one and decreases thus significantly the iteration cycle of the PBR design process.
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Effect of water deficit on the energy content of individual plant organs in selected species of leafy vegetables
Šimůnková, Petra ; Hnilička, František (advisor) ; Česká, Jana (referee)
This work presents the impact of water deficit on dry mass production and photosynthetic accumulation of energy on every single plant´s organs of selected plant species. As a chosen experimental material were taken plants of Spinacea oleracea "Matador" sort and Tetragonia tetragonioides.
Spinacea oleracea and Tetragonia tetragonioides plants were grown in containers 11x11cm large in mixture of garden substrate A with silicon sand (2:1) in 2 variations placed in FAPPZ greenhouses. One variation was for control and second was exposed to stress reaction. Control variation had been watered for whole time of experiment with 50ml of water 2 times per week. Stressed one had been watered after puncturing and 6. taking until the end of experiment.
During the plant´s ontogenetic evolution had been monitored dry mass´s weight on singular plant´s organs. With usage of burnt calorimetry method had been monitored capacity of photosynteticaly accumulated energy in dry mass. Quantity of netto energy had been found out by dry burning adiabatic calorimeter LAGEST MS 10A.
From the gained results emerge, that plants of Tetragonia tetragonioides have 2 times higher weight growth apart from Spinacea oleracea. Control plants of Tetragonia tetragonioides have higher weight by 25,5% (123 mg) compared to the plants growing in water deficit. Likewise higher weight of roots had been observed on control plants (41 mg) compared to the stressed plants (40 g). Control spinach plants had higher weight of above-ground biomass by 19,5% compared to the stressed ones (43 mg). Roots of control plants had lower weight compared to stressed variant by 2960 mg.
From the results emerge, that plants of Tetragonia tetragonioides have higher weight of roots dry mass and above-ground biomass compared to the Spinacea oleracea plants.
Burning heat without ashes was on above-ground biomass of control plants Tetragonia tetragonioide on 15,96 kJ.g-1 level and on stressed plants 14,93 kJ.g-1 . In case of Spinacea oleracea plants was amount of control plants energy 14,98 kJ.g-1 and on stressed 14,21 kJ.g-1.
Burnt heat without root ashes of Tetragonia tetragonioides control plants was higher by 1.11 kJ.g-1 then on stressed ones (13,19 kJ.g-1). In case of Spinacea oleracea plants was amount of roots energy on control plants 11,90 kJ.g-1 and on stressed 11,72 kJ.g-1 .
Based on measurement were verified differences between species in reaction on water deficit and observed characteristic. From measuring emerged, that Spinacea oleracea plants are more sensitive on effect of water deficit compared to the Tetragonia tetragonioides
plants, which is more tolerant. Next thing observed is, that there are differences in amount of dry mass and rate of burnt heat in relation on effect of water deficit.
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Undeclared Employment in theTheory and Practise of The Labour Inspectorates
Kaufmanová, Renata ; Světlíková, Daniela (advisor) ; Klára, Klára (referee)
The thesis describes the issue of illegal employment, with emphasis on the analysis of illegal work in the Czech Republic and depending on the control activities carried out by labor inspectorates. Using the characteristics of the basic concepts (dependent work, illegal labor, labor inspectorates) with the help of current judgments given area, the current status and the possibility of the activities of labor inspectorates. The practical part deals, through interviews among the employees of labour inspectorates and experts, the specific situation of control activities and proposes solutions to streamline and harmonize the theory and practice of inspection activities in the illegal employment in the Czech Republic.
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Secure access to local area network
Kočiš, Jan ; Halbich, Čestmír (advisor) ; Radomír, Radomír (referee)
This master's thesis deals with the field of secure access to the local area computer network. The main aim of the thesis is to characterize theoretical background of controlled access to computer networks, which includes security principles, recommended practices, authentication methods, network protocols and related processes. This thesis also includes practical usage of acquired knowledge by implementing secure access to local area network in a real environment.
The first part characterize the theoretical principles underlying the design and implementation of the entire system.
The practical part deals with the implementation of specific secure access to the local area computer network solution in the engineering company. The first part introduces the company, its environment and requirements. The following section describes performed analysis of the original state and based on the obtained information summarizes the proposed solution. Implementation of the comprehensive system of the controlled access to the local area network is described in detail in the next section. Description of the system deployment into production operation process, the definition of acceptance tests and recommendations for solving of potential issues are part of this work as well. Conclusion chapter contains summary of the system's economic aspects and the potential impacts on information systems operation in the company.
Final evaluation summarizes the thesis, highlights the benefits of the implemented system and analyses its weak points, with recommendations for further development. It finds the designed secure access to the local network as a suitable, secure and practical way to control access to local network resources.
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Surface runoff generation and its erosion processes
Kalibová, Jana ; Kovář, Pavel (advisor) ; Štibinger, Jakub (referee)
Research of model simulations of hydrological data for water resources studies and field and laboratory experiments testing the effectiveness of erosion control geotextiles using rainfall simulators is summarized in this dissertation. The results of the research have been used to suggest a water regime optimisation in the catchment of a former mining pit Medard-Libík. Although agricultural and forestry reclamation measures have been applied, rill erosion still appears on some slopes within the catchment. The soil loss and sediment transport result in the deterioration of the crop yield, cause damage on the road and drainage systems and also influence the quality of water in the lake arising by flooding the former mining pit.
The first part of the dissertation provides a review on surface runoff and its erosion processes. Next, bio-technical erosion control measures on slopes are summarised. The third part of the dissertation is devoted to a simulation of surface runoff on a model slope in the Medard Catchment. The main aim was to test whether the KINFIL model is suitable for the simulation of the effectiveness of erosion control geotextiles and suggest an appropriate erosion control measures for the eroded slopes in the Medard Catchment.
The KINFIL model seems to be a useful tool to quantify the effectiveness of individual erosion control products and measures in order to find the most convenient option. The simulations carried out in the dissertation corresponded to the results of field and laboratory experiments testing the impact of geotextiles on surface runoff and soil erosion published earlier.
A well-balanced rainfall-runoff regime in the Medard Catchment would increase the stability of the landscape, reduce the cost of restoration of the damage caused by erosion to road and drainage systems and improve the water quality by elimination of the sediment transport. The results of this dissertation may be offered to the public administration or private stakeholders to control erosion within the reclamation of areas affected by mining activities.
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Impact of rainwater management on mitigation of hydrological extremes
Pešková, Jitka ; Štibinger, Jakub (advisor) ; Miroslav, Miroslav (referee)
This dissertation deals with the impact of rainwater harvesting on mitigation of hydrological extremes. Due to the fact that it is a very broad topic that cannot be completely elaborated, the work targets selected aspects of this issue. The work is divided into two parts. The first part is divided into the following five chapters: The water in the landscape, Water regime, Hydrological extremes, Water regime adjustment and Legislation. These chapters summarize available worldwide knowledge about rainwater harvesting both in the landscape and in urbanized areas with a focus on mitigation of extreme hydrological phenomena (floods - drought), including legislative security of water management on national and EU level.
The second part of the thesis is compiled in the form of an annotated set of four scientific studies, whose results were presented in articles published in scientific journals. The first study targets the efficiency of torrent control (hydro-technical point of view and migration of water fauna). The second study focuses on the territory of the Morava River floodplains, where negative impacts of floods and droughts appear repetitively. The study solves the hydrological balance of the area using the WBCM-7 model. The third study focuses on computation method of the retention drainage capacity in the agricultural area drained by subsurface pipe drainage system. The last paper describes a new application of the Fourier series for detailed simulation of the runoff on a catchment in the dry periods. Within the thesis, these studies have been interconnected by explanatory comments.
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Characteristics of rainfall in observed data and regional climate model simulations
Svoboda, Vojtěch ; Pech, Pavel (advisor) ; Josef, Josef (referee)
Precipitation in the form of heavy rainfall events is of significant societal concern, not only due to the potential for more frequent flash floods, after evidence of changes in rainfall characteristics has recently strengthened. Despite the importance of individual rainfall events with respect to many hydrological applications, only a few studies dealt with characteristics of individual rainfall events (in contrast with the other daily/sub-daily indices of rainfall depths/intensities). Dissertation thesis presents a comprehensive analysis of heavy rainfall event characteristics for the Czech Republic derived from observed data and large ensemble of regional climate model (RCM) simulations. In addition, spatial correlation structure of observed rainfall data at a mesoscale region of north-eastern Bohemia was analysed. Since an RCM grid box represents a spatial average rather than a point measurement, the effects from areal averaging of rainfall data on characteristics of events were investigated considering the observed data. Characteristics of rainfall events were evaluated according to several indices against the at-site and area-averaged observed data for the control period 1981-2000. The changes of rainfall event characteristics were assesed over two scenario periods (2020-2049 and 2070-2099) with respect to control period. We analysed also relations between changes in simulated rainfall event characteristics and changes in radiative forcing and temperature.
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Valve controls and their timing
Vajčner, Patrik ; Pexa, Martin (advisor) ; Kotek, Tomáš (referee)
Abstract: Comparison of different types of valve operating mechanisms is the main aim of the Bachelor thesis. This was done from the point of view of the construction manufacturing, with regard to the engine performance, user´s comfort and fuel consumption of a vehicle. There were two types of valve operating mechanisms chosen for the purpose of the Thesis. The first one is a typical classic system whereas the second one is a modern type with a possibility of timing, which allows different timing for valves opening and closing. This process is dependent on the current requirement of engine output. Achievement of the optimal engine output for every specific type of ride is not the main purpose of the correct timing of valves and engine run adjustment in a vehicle. It also allows for a reduction of the excessive engine load and gradual wearing of each part of the system. Of course another very significant reason is to lower the fuel consumption as much as possible with regard to reduction of harmful, environmental unfriendly gases and emissions.
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