|
|
High Temperature Processes in Silicon Solar Cells Production
Frantík, Ondřej ; Hudec, Lubomír (referee) ; Banský,, Juraj (referee) ; Szendiuch, Ivan (advisor)
The thesis is focused on high temperature processes in crystalline solar cells production. Main topic is diffusion of traditional dopants phosphorus and boron. Diffusion processes for creating solar cells are different from classical diffusion in semiconductor industrial. It is reason why the thesis describes crated layers in detail. Knowledge of diffusion processes is used for creating bifacial solar cells and development of a new phosphorus emitter for conventional solar cells. Bifacial cells are a new type of cells. Developed new emitter increases efficiency and decreases cost of solar cells production. Another part the thesis is devoted to the prediction of diffusion processes. New models of phosphorus and boron diffusion for photovoltaic industrial are created in software SILVACO. Models correspond with real results.
|
|
|
Issues of boron in water
Šípková, Helena ; Nevrlá, Jana (referee) ; Komendová, Renata (advisor)
This bachelor thesis is focused on boron and its compounds. It is dedicated to properties, sources and the use of these substances and their effects on living organisms. The emphasis is put on the issue of boron in water. In this work are possible forms of this element in water, legislative rules and regulations and methods of its determination described. The experimental part is focused on azomethine-H spectrophotometric analysis to identify the stability of boron samples and their possible preservation.
|
|
|
Fluoride coatings on magnesium prepared in melts
Drábiková, Juliána ; Richtera, Lukáš (referee) ; Zmrzlý, Martin (advisor)
This work deals with the corrosion protection of magnesium alloy AZ31, AZ61, AZ91 using fluoride conversion coating prepared from Na[BF4] melt. The theoretical part describes the properties of magnesium alloys, the recent results of fluoride conversion coatings preparation and analysis of the available literature about the properties of salt Na[BF4] and its decomposition products. The experimental part was devided into two main sections. The first deals with the corrosion resistance of the treated magnesium alloys (AZ31, AZ61, AZ91 and AZ91 annealed) in the Na[BF4] melt. Corrosion resistance was tested using potentiodynamic tests and tests in the corrosion chamber. In the second part, the mechanism has been studied for preparing fluoride conversion coating, where it was shown that in air-free atmosphere the oxidizing agent in the process is boron, which is reduced from BIII to B0, and thereby enables the fluoride conversion coating.
|
|
|
Nuclear Fuel in Operational Conditions
Konopová, Tamara ; Novotný, Filip (referee) ; Katovský, Karel (advisor)
This thesis deals with the issue of nuclear fuel. Firstly, the problem of nuclear fuel in the implementation for certain reactors is presented. Production of nuclear fuel is introduced, which includes the performance of companies engaged in the production of this fuel. Secondly, the phenomena in the fuel burnup are discussed. Lastly, the burnable absorbers are mentioned and the analysis of burnable absorbers is carried out.
|
|
|
The effect of production parameters on the plasticity of structural steel
Brabec, Martin ; Podaný, Kamil (referee) ; Peterková, Eva (advisor)
The master thesis deals with the influence of heat treatment and storage time on microstructure and mechanical properties of 26MnB5 steel, which is used in the production of tubular components in the quenched and tempered state. The objective was to increase the plasticity of the steel by the definition of new process parameters of the induction heat treatment line. New tempering diagrams of 26MnB5 steel for two various speeds of the heat treatment line were established and used to determine new tempering temperature and speed of the heat treatment line. Observation of the influence of storage time on mechanical properties of the steel did not reveal that it is liable to ageing.
|
|
|
Microdefects in Czochralski Silicon
Válek, Lukáš ; Fejfar, Antonín (referee) ; Mikulík, Petr (referee) ; Spousta, Jiří (advisor)
Disertační práce se zabývá studiem defektů v monokrystalech Czochralskiho křemíku legovaných bórem. Práce studuje vznik kruhových obrazců vrstevných chyb pozorovaných na povrchu křemíkových desek po oxidaci. Hlavním cílem práce je objasnit mechanismy vzniku pozorovaného rozložení vrstevných chyb na studovaných deskách a vyvinout metody pro řízení tohoto jevu. Na základě experimentálních analýz a rozborů obecných mechanismů vzniku defektů jsou objasňovány vazby mezi vznikem defektů různého typu. Tyto jsou pak diskutovány v souvislosti s parametry krystalu i procesu jeho růstu. Takto sestavený model je využit pro vývoj procesu růstu krystalů, kterým je potlačen nadměrný vznik defektů ve studovaných deskách. Za účelem studia defektů jsou zaváděny a vyvíjeny nové analytické metody. Disertační práce byla vytvořena za podpory ON Semiconductor Czech Republic, Rožnov pod Radhoštěm.
|
|
|
Využití humátů v kombinaci s bórem ve výživě řepky ozimé
Rzymanek, Jakub
The aim of the thesis was to assess the effect of foliar application of boron (B) together with humate on yield and oil content of rapeseed (Brassica napus L.). For this purpose, a one-year field trial was evaluated. In this trial two different fertilizers containing boron were used. These fertilizers were applied both without and in combination with humate. In each treatment, a total of 300 g of B/ha (in the form of borethanolamine) and humate in a dose of 2 l/ha were applied. In one variant, humate without boron was used, in a total dose of 2 l/ha. The average of two unfertilized control treatments was used for comparison. A significant effect of boron used with humate on the yield of winter rape was reached (highest gain by 7.93%) in comparison to the control. A positive effect on seed yield was also reached by application of boron without humate in B2 treatment (+ 6.83%), which was significant compared to the control and compared to the B1 treatment too. Significant yield effect (+ 2.55%) in comparison to the control was reached also by application of humate without boron. A very small effect of boron fertilization on oil content was found. The highest oil content was reached by the separate use of humate (+ 1.19%). The treatments were also evaluated in terms of economic efficiency. Based on the results of yield obtained and economic efficiency of treatments, the B1 + NF treatment was chosen as the best one.
|
|
|
Application of modern analytical methods for the study of selected boron coordination compounds
Hrušková, Helena ; Jelínek, Ivan (advisor) ; Dian, Juraj (referee)
This thesis is focused on the study of boron coordination compounds, specifically boron pyrogallol and 2,3-dihydroxynaphthalene ligand complexes. In the introductory part of the work are discussed the properties of boron compounds, their preparation, the possibility of separation by capillary electrophoresis and methods of structural characterization. In the first part of the thesis, the methods of preparation of complexes are discussed and for each complex the optimal yield response is chosen. The resulting products were studied by low resolution mass spectrometry. In the second part of the thesis, structures of complexes, including their modeling in the Gaussian program, were described more precisely. Furthermore, the complexes were characterized by high resolution mass spectrometry. The complexes were also studied by 11 B, 1 H and 1 H COSY NMR and IR spectroscopy. The third part was devoted to the separation of these substances from the mixture after the reaction. CE-UV and CE-MS techniques were used for this purpose. To convert the results, the separation method was developed in ammonium formate buffers that are compatible with both instruments. The equilibration between complexes and ligands was also monitored by CE-UV. A special chapter is the study of pyrogallol autooxidation by UV-VIS and...
|
|
|
Contamination of Peruvian drinking water by arsenic and boron - origin, properties and treatment
Sadloň, Matúš ; Stejskal, Vojtěch (advisor) ; Cencarová, Vendula (referee)
Excessive arsenic and boron concentrations determined in natural waters within the Department of Tacna in southern Peru are associated with active Andean volcanism, being further exacerbated by the ongoing mining activity in the area. Both arsenic and boron concentrations at five investigated sites significantly exceed the maximum permissible limits determined by the World Health Organisation and the Peruvian legislation for drinking water, thus affecting the health and wellbeing of the local population. Due to the remoteness of the area of interest, which lacks infrastructure, skilled human resources as well as capital, Photon Water Technology s.r.o. has come up with a solution based on the use of small water treatment plants operating on the principle of reverse osmosis in combination with a commercial remediation product Katalox Light® . This product enables the formation of alkaline conditions needed for proper complexation of boron into B(OH)4 - (aq), which is better remediated by the proposed technology. Reverse osmosis can remediate arsenic, although the efficiency of As removal depends on the chemical composition of natural waters at the investigated sites. Laboratory experiments have been focused to prove the viability of Katalox Light® for enhancing the rate of boron removal within the designed...
|
|
|
Působení aplikace hnojiv na bázi síranu amonného na výnos a olejnatost semen řepky ozimé
Vrtěl, Petr
This thesis follow up influence of fertilization on yield and oil content of oilseed rape (Brassica napus L.). There were used fertilizers based on ammonium sulfate in the regeneration (BBCH 26, spring) and production fertilization (BBCH 31) during vegetation phase of oilseed rape. The issue was solved as a two-year small-plot field experiment carried out in the vegetation seasons 2016/2017 and 2017/2018 at the Field Experimental Station in Žabčice. The following variants were included in the experiment: Control (CAN), Ammonium sulfate (AS), Ammonium sulfate with boron (AS + B), Ammonium sulfate with nitrification inhibitor (AS + IN). Each fertilization variant was applied either as regenerative fertilization (BBCH 26) or first production fertilization (BBCH 31). The yield of seeds and also their oil content was significantly influenced by the vegetation season. Yield in the vegetation season 2017/2018 were higher by 41 % than in the vegetation season 2016/2017 because of weather conditions. The oil content was higher by 4 % in the vegetation season 2017/2018. The yield of seeds and also their oil content were not significantly influenced by the fertilization variant or by the vegetation phase of application. The highest average yield 4,23 t/ha was variant Control. The Control also was the highest average oil content of 40,2 %. High temperatures during both years reduced the efficiency of nitrification inhibitor. Fertilization with a boron-containing fertilizer had no effect because of drought and pH.
|
guest ::
