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Research on Effective Methods of Exhausting
Pech, Ondřej ; Kratochvíl, Zdeněk (referee) ; Černecký,, Jozef (referee) ; Pavelek, Milan (advisor)
Many production technologies generate a variety of gas pollutants, which are unhealthy. The aim is therefore to minimize the content of such gas pollutants in the work environment. The highest capture efficiency of gas pollutants offers the local exhausting. Its disadvantage is the necessity to surround the source of pollutants, or to be as close as possible which is usually not technically or technologically possible. A possible alternative is to use a reinforced exhaust system that achieves greater capture distances. In the initial stage of the solution of the dissertation, a review of reinforced exhaust systems was carried out. Further, an existing measurement system was modified for measurements with the partition above the exhaust slot and the measurement system was partially automated. In order to investigate the case with pollutants having a lower density than the air, the workbench - the partition was moved above the exhaust slot. Based on of the literature review, a modification of the reinforced slot exhaust system was proposed. The modification consisted in the adjustment of the air inlet adjustment where a set of holes and a tube assembly were used instead of the slot. Such setup allowed for higher flow turbulence and thus for an increased exhaust efficiency. Subsequently, the inlet streams from the slot, holes and tubes were visualized by the smoke method. Further measurements were carried out by the tracer gas method for the determination of the exhaust efficiency. Measurements of velocity fields in front of the proposed configurations of the reinforced slot exhaust hood were also carried out. In conclusion, an energy performance assessment was carried out by means of the measurement of the electric power input to the fans with the determination of the electric loss power.
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The Study of Biopolymers Stability Using Light Scattering Techniques
Kratochvíl, Zdeněk ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
The stability of chosen biopolymers (or simple carbohydrates and amino acids) was in-vestigated using light scattering methods. Samples were prepared by dissolving the sub-stance in deionised water or in diluted acetic acid. Firstly, the effect of increasing concen-tration on zeta potential was observed and the optimal concentration for the next measure-ments was determined. Afterwards, the stability and the molecular weight of used sub-stances were studied during long-time storage in different time intervals. It was found out that chitosan, CMC, hyaluronate and sodium alginate were subjected to degradation whereas increase of the molecular weight and the zeta potential was observed in case of BSA. In the end, the samples were exposed to several different external effects, namely the influence of different temperatures, UV radiation and increasing ionic strength. The results showed that rather higher temperature has a significant impact on biopolymers stability. However, used biopolymers were hardly affected by UV radiation except BSA whose molecular weight increased considerably. Decrease of the zeta potential absolute values and the molecular size usually occurred with increasing ionic strength. The change of molecular weight was not detected.
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Data Backup and Data Storrages
Šulc, Ondřej ; Kratochvíl, Zdeněk (referee) ; Kříž, Jiří (advisor)
This thesis focuses on the design of the backup system for elementary school Humpolec, Hradská 894. Introduction deals with the theoretical knowledge of the subject. The following section analyzes the current status of the backup system, including the information about the network system. The third section contains my own solutions, suitable for this school, based on findings in the analytical part.
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Transport and Deposition of Aerosol in Human Respiratory Tract
Elcner, Jakub ; Kratochvíl, Zdeněk (referee) ; Volavý, Jaroslav (referee) ; Jícha, Miroslav (advisor)
One of approaches in treatment of respiratory system diseases is the use of drug particles suspended in air in the form of aerosol. It is a fast and non-invasive method for the delivery of medicine into tracheobronchial tree or bloodstream. Although the method of the medication dosage by means of inhalers or nebulizers is well known, the effectiveness of that approach is still an actual issue. A significant amount of drugs delivered with the use of the medication dosage never reaches its primary destination and the drugs deposit in antecendent areas of respiratory tract where their presence is not required. This thesis deals with a problem of the passage of monodisperse homogenous aerosol with micron-size particles through the upper parts of the respiratory tract. This work was created with the use of numerical simulations carried out by means of the finite volume method in the commercial code based on computational fluid dynamics. Turbulence was modelled using the Reynolds averaged Navier–Stokes equations with the two-equation eddy viscosity k-omega SST model. The main output of the thesis is the analysis of airflow in two respiratory regimes. Stationary and cyclic cases of the flow behaviour were considered and the validation of simulated results with experiments performed on similar geometries was carried out. Furthermore, the review of simplified lung models and their geometries was made and the acquired results were used for the calculation of air distribution in the respiratory tract. The last part of the thesis deals with the calculation of particle deposition and with the analysis of the results.
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Change in the Production of oversize Components of the Pump
Kratochvíl, Zdeněk ; Prokop, Jaroslav (referee) ; Kalivoda, Milan (advisor)
The thesis proposes a method for implementing structural changes on the compression flange of the main circulation pump, at the time of its overhaul during the unit outage. This structural modification consists in Annular groove of the groove to a diameter of about 850 mm. It is necessary to choose a suitably radius of maximum made possible smoothly rounded grooves without notches to reduce the stress of the concentration at the corners of the groove. Possibilities for making this adjustment are considered in this thesis and then the technology is selected with control torque calculations. The selected technology consists in the sizing of grooves with the mobile numerically controlled machining lathe EFCO TDF-2 NC, which is documented in the Annular groove of the axial grooves. In conclusion there are described other possibilities of using of this mobile machine in the primary circuit of a nuclear power plant.
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Coupling of the Models of Human Physiology and Thermal Comfort
Pokorný, Jan ; Masaryk, Michal (referee) ; Kratochvíl, Zdeněk (referee) ; Jícha, Miroslav (advisor)
The thesis deals with car cabin environment and thermal comfort inside. A car cabin heat load model was developed in Dymola/Modelica to investigate influence of ambient environmental parameters. The model was validated on the data set of eight test cases measured in a climatic chamber and in a real traffic. The main objective of the thesis was to develop a human thermal comfort model suitable for non-homogenous environments and for a car cabin environment especially. The Coupled model of human physiology and thermal comfort was developed in Dymola/Modelica. The model allows predicting an overall human thermal comfort from local boundary conditions representing ambient and personal factors. The model was validated by 16 test cases taken from experiments in literature. Moreover three test cases were created in Theseus-FE to consider an asymmetrical heat load from Sun rays inside a car cabin. Prediction of the Coupled model was compared with Fiala model and experimental data. The Coupled model predicted mean skin temperature for moderate activities in neutral and warm environment well. In cold environment a predicted core temperature was very affected by ambient temperature and during high activity exercises, the predicted mean skin temperature was too high.
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Renewal of hermetic pipe penetrations
Kratochvíl, Zdeněk ; Chladil, Josef (referee) ; Kalivoda, Milan (advisor)
The topic of this work is the renewal of hermetic pipe penetrations within the primary loop of a nuclear power station. A description of the Dukovany nuclear power plant is included at the beginning, ranging from basic description to details of the renewed component and the reasoning for its replacement. Following is a description of the technologies, which are applied in order to restore the hermetic pipes, the choice of the placement of the heterogeneous weld and the compilation of a workflow for the renewal in the environment of the primary loop while maintaining the quality standards and the strict safety conditions. The conclusion includes a calculation of the expenses tied with the chosen variant the reasoning behind the renewal regarding the length of the outage.
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Ground Heat Exchangers - Operating States and their Influence on Microbiological Hazards
Kolbábek, Antonín ; Klánová, Kateřina (referee) ; Kratochvíl, Zdeněk (referee) ; Jaroš, Michal (advisor)
This thesis deals with the Air to Ground Heat Exchangers (AGHEx) and their effects on the hygienic quality of the supplied air and the microbial microclimate in the interior of buildings. The theoretical part focuses on current findings and knowledge in the field of warm air heating, ventilation of the low-energy and energy passive houses and ground heat exchanger for the ventilation systems to family houses. The next chapter deals with the quality of the indoor environment and the influence on HVAC systems on the building microclimate. The experimental part of the thesis presents the results of energy simulations of operation of air to ground heat exchanger, obtained using the simplified model, and the data from long-term monitoring of experimental AGHEx built at FME BUT. Furthermore, the results of microbiological research of several already operating air to ground heat exchangers are evaluated. The research was carried out using two different sampling methods: the method using swabs taken from the pipe wall, and the sedimentation (gravimetric) method. The conclusion part mentions the practical experiences of users and knowledge of the author relating to the design, operation and use of air to ground heat exchangers.
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