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Comparison of Dry and Wet Oxidation Process during Low Pressure Boron Diffusion with BBR3 in Solar Cell Production
Mojrová, B.
This paper deals with replacing a dry oxidation with a wet oxidation process during low pressure diffusion using boron tribromide (BBr3) in solar cell production. Because the liquid boron trioxide (B2O3), a product of a chemical reaction during diffusion, condenses apart from wafers on walls of quartz tube, it is essential to clean the tube after diffusion. This could be done by evaporation of water into the tube after unload or, in order to make the production time shorter, by replacing the dry oxidation with wet oxidation process. In this paper a comparison of the wet and dry oxidation is given with regard to the solar cell production.
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Balance-related exercise as a preparation to cross-country skiing practice in visually impaired children
Chmelíčková, Hana ; Daďová, Klára (advisor) ; Levitová, Andrea (referee)
Title: Balance-related excercise as a preparation to cross-country skiing practice in visually impaired children. Objectives of the Thesis: The goal of this thesis is to test the possibilitiy of implementation of selected balance- related excercise in visually impaired children. Method: The testing pool consisted of six pupils attending the Special school for Visually Impaired Children between 14 and 15 years of age. Over the period of ten weeks, selected exercise geared towards the cross-country skiing was practiced with these students. The research method applied to measure students' indicators of balance before and after the excercise was an assessment of standing stability at the Footscan pressure table, as well as a walking test in terrain with blinded eyes. Results and Conclusions: This research has indicated the possibility of physical intervention in form of balance- related practice as part of the preparation before the cross-country skiing season begins. It has proven that selected balance-related excercise can be applied with no limitations during the physical education classes for visually impaired pupils. After the physical intervention, the majority of tested individuals showed improvements in their indicators of dynamic balance, as proved by the walking test in terrain with blinded...
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Two-step sintering of advanced ceramic materials with various crystal structures
Žalud, Pavel ; Trunec, Martin (referee) ; Maca, Karel (advisor)
The influence of Two-Step Sintering (TSS) process on the final microstructure of oxide ceramics materials with two different crystal structures was studied. Tetragonal zirconia (stabilized with 3mol%Y2O3, particle size 90nm and 140nm ) and cubic zirconia (8mol%Y2O3, 70nm) powders were cold isostatically pressed and pressure less sintered with different heating schedules. The microstructures achieved with TSS method were compared with microstructures achieved with conventional Single-Step Sintering schedule (SSS). The results showed that the efficiency of the TSS of these oxide ceramics was more dependent on their crystal structure than on their particle size and green body microstructure. The method of TSS brought only negligible improvement of the microstructure of tetragonal zirconia ceramics. On the other hand, TSS was successful in the sintering of cubic zirconia ceramics; it led to a decrease in grain size by a factor of 2.
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Treatment of pulmonary hypertension affect the metabolism of cyclic guanosine monophosphate
Al-Hiti, Hikmet ; Kettner, Jiří (advisor) ; Ošťádal, Petr (referee) ; Goncalvesová, Eva (referee)
Chronic damage to pulmonary vessels leads to pulmonary hypertension (PH). Different forms of PH are quite frequent and are associated with significant morbidity and mortality. The treatment of PH is most successful, if its cause can be identified and removed before irreversible damage to the pulmonary vascular bed occurs. For patients, in whom the elimination of the underlying cause is not possible or where the cause is unknown, the treatment is aimed at reduction of pulmonary vascular resistance and improvement of cardiac and circulatory response to pressure overload of the right ventricle. One option for the PH treatment is modification of metabolism of cyclic guanosine monophosphate (GMP), which is the second messenger of nitric oxide and induces vascular vasodilation. Cyclic GMP is degraded by phosphodiesterases (PDE 5). In the clinical part, we tested the hypothesis that acute inhibition of PDE5 by sildenafil provides more selective pulmonary vasodilation than high doses of prostaglandin E1 (PGE1). The study showed that the vasodilator effects of sildenafil on pulmonary circulation is more pronounced than in the systemic circulation and that sildenafil had a greater ability to detect reversible component precapillary PH due to advanced chronic heart failure than PGE1. The aim of our...
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Decompressive craniotomy in craniocerebral injury - evaluation of outcome one year after trauma
Navrátil, Luděk ; Choc, Milan (advisor) ; Náhlovský, Jiří (referee) ; Haninec, Pavel (referee)
The study presents analysis of group of 110 patients treated for craniocerebral trauma by means of decompressive craniotomy between January 1999 and December 2003. The influence of different factors to the outcome of patient one year after injury was evaluated. Among the factors in view we included age, clinical status and its worsenig after admission, accompanying injuries, time period between injury and operation, finding during operation, intracranial pressure and postoparative complications. In addition to evaluation of particular factors to the outcome of patients we followed the correlation between various factors. Results: perimesencephalic cisterns and thickness of subdural hematoma were evaluated. In the subgroup of patients with subdural hematoma (n=63) it was found, that worsening of the outcome correlated with the thickness of subdural hematoma (p = 0.,025) and with the shift in the CT (p = 0.0001). Correlation between shift or width of cinsterns to the outcome of all patinets (n = 110) was not found. The perioperative measurement of dural gap before the duroplasty is the speciality of this work. In all patients (n = 110) the correlation between dural gap and the outcome was not found. In older patients the dural gap was lesser (p = 0.021). But in older patients the subdural hematoma was...
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Polymeric Hollow Fiber Heat Exchanger Design
Astrouski, Ilya ; Dohnal, Mirko (referee) ; Horák, Aleš (referee) ; Raudenský, Miroslav (advisor)
This Ph.D. thesis is focused on theory and experimental investigations developing of new knowledge about polymeric hollow fiber heat exchanger (PHFHE). The state-of-the-art study of plastic heat exchangers shows that their usage is limited by several niches where their advantages significantly dominates, or where the use of non-plastic competitors is not impossible. On the other hand, plastic heat exchangers (and PHFHEs in particular) are devices of increasing interest. It is shown that use of small tubes (fibers) allows PHFHEs to be more competitive than conventional plastic heat exchangers. Small hydraulic diameter of a fiber causes high heat transfer coefficients, reduces thermal resistance of plastic wall and allows it to create light and compact design. Detailed study of fluid flow and heat transfer inside the hollow fiber showed that conventional approaches for single-phase laminar flow can be utilized. Poiseuille number equal to 64 and Nussel number about 4 are recommended to be used to predict pressure drops and heat transfer coefficient, respectively. Additional attention should be paid to careful determination of fiber diameter and liquid properties (viscosity). Scaling effects, such as axial heat conduction, thermal entrance region and viscous dissipation can be neglected. The study of outside heat transfer showed that heat transfer on fiber bunches are intense and are competitive to contemporary compact finned-tube heat exchangers. The Grimson approach showed clear correlation with experimental results and, thus is recommended to predict heat transfer coefficients on fiber bunches. Two types of fouling (particulate- and biofouling) of outer fiber surface were experimentally studied. It was found that particulate fouling by titanium oxide particles is not intense and deposits can be removed relatively easy. However, fouling is much more intense when it is associated with biofouling caused by wastewater. In this case, smooth and low-adhesive surface of plastic is not sufficient precaution to prevent deposit formation.
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Analysis of the imaging of the movement of the diaphragm using magnetic resonance in combination with spirometry investigation
Kolář, Pavel ; Kučera, Miroslav (advisor) ; Musil, Jaromír (referee) ; Herget, Jan (referee) ; Pafko, Pavel (referee)
The thesis evaluates respiratory and postural function of the diaphragm, studying how the two diaphragmatic functions are interrelated. Th e author of the thesis is interested in the postural function of the diaphragm because of its stabilization role on the spine. Th e diaphragm helps to regulate (increase) intraabdominal and intrathoracic pressure, thus bracing the spine while the external forces act on the spine. Disturbed postural activity of the diaphragm is considered to be one of the most frequent etiopathogenetic factors in vertebrogenic syndromes. In this research function of the diaphragm was analyzed during respiration and during postural function of the diaphragm, i.e. independently on respiration, by means of dynamic magnetic resonance (MR). Diaphragmatic dynamic magnetic resonance studies were synchronized with spirographic records. In the probands spirometric studies were also carried out, including force analysis of the respiratory muscles, as well as EMG diaphragmatic activity. 30 healthy individuals of mean age 29,3 years (ranging from 22,2 to 56,2 years) were involved in the study. Diaphragmatic activity was studied during primary breathing and in the course of upper and lower extremities' fl exion against resistance, under two circumstances, while breathing and while holding the breath....
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Study of Constructed Treatment Wetland Reconstruction for Dražovice Village
Roupec, Ladislav ; Pumprlová Němcová, Miroslava (referee) ; Kriška-Dunajský, Michal (advisor)
The constructed wetlands, which have been being created in the Czech Republic since early 90s, are designed so they do not allow successful removal of ammonia nitrogen. Almost all of these 300 registered constructed wetlands suffer from the colmatage which leads to the lowest effectiveness of treatment in nearly all parameters. The main effort of the Institute of landscape water management is to get rid of bad reputation and to clarify the reason that leads to unsatisfactory conditions of constructed wetlands. The diploma thesis focuses on the selected constructed wetland in Dražovice (850 EO), which removes ammonia nitrogen with the effect just below the limit values in the long term. The pressure of the Morava river basin and Department of environment (Building Authority in Bučovice) has led to the necessity of taking measures leading to the increase of treatment efficiency especially ammonia nitrogen. The diploma thesis includes both, actual project documentation concentrating on the adjustment of watercourse to nitrify ammonia nitrogen, and effective choice of suitable filtration material supported by testing method in situ. The practical part of the thesis deals with the implementation of the technical solution according to the project documentation. The adjustment of the constructed wetland is now nearly before completion. Last adjustments will be taking place during the spring 2017, the final inspection as well as the evaluation of the reconstruction will take place at the end of this year.
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