|
|
Kinetics of benzo[a]pyrene destruction and identification of its products
Ryšavý, Jan ; Kolek, Emil (referee) ; Šimko, Peter (advisor)
This diploma thesis is focused on the study of conditions of benzo[a]pyrene, one of the major contaminant of foods, photodegradation under different conditions (solvents with different polarity, light sources, presence of antioxidants). In another part of the thesis, the degradation process of benzo[a]pyrene at various concentrations was studied, in order to characterise the kinetic aspects of photoinduced degradation. The attempt to identify the products of benzo[a]pyrene photodegradation was performed involving methods of gas chromatography and high performance liquid chromatography coupled with mass detectors, as well.
|
|
|
Study of AlSi protective coating after degradation
Vítková, Gabriela ; Řičánková, Veronika (referee) ; Hutařová, Simona (advisor)
Materials used for high temperature applications works in a very aggressive environment (oxidation, hot corrosion, erosion, fatigue, creep). Demands on these materials are very high. Nickel-based superalloys show the certain stability in this environment. Improved resistance to oxidation and hot corrosion can be achieved by using protective layers such as diffusion barriers. This thesis is focused on changes of microstructure and properties of AlSi layer applied by „slurry“ method on nickel-based superalloy Inconel 713 LC, due to long-term thermal exposition at 800, 900 a 1000 °C.
|
|
|
The problems of fenol sorption from waste water
Židek, Michal ; Pavlovský,, Jiří (referee) ; Doležalová Weissmannová, Helena (advisor)
The bachelor work deals of sorption of phenol from waste water. In theoretical part the basic characteristic of phenol, their effects and presence in environmental compounds are described. The possibility of removal phenol from waste water in waste water treatment is also described. The adsorption process of removal phenol introduced too. The analysis current adsorbents using in removal phenol from aqueous solutions and characteristic properties are also presented in relation to materials on the base of clay minerals. The experimental part is focused on the possibility of removal phenol from aqueous solution via adsorption mechanism under various pH conditions.
|
|
|
Testing of polymeric materials under climatic conditions of Antarctica
Mičkal, Petr ; Sluková, Michaela (referee) ; Krmíček, Lukáš (advisor)
The bachelor's thesis generally deals with polymer materials and evaluates the possibility of testing their resistance to extreme climates of Antarctica. Described herein are various polymer materials, their characteristics, structure, properties and more thorough and detailed descriptions of selected polymers. The next section describes the basic types of degradation these polymers are exposed to, when facing the extreme conditions of the Antarctic climate. The practical part contains evaluations of tests made on the degraded polymer materials that were collected in Antarctica during the southern Antarctic season of 2013-2014 by Ing. Bc. Pavel Kapler, Ph.D, who is a superintendent at the Czech scientific station JG Mendel.
|
|
|
Role kyslíku při výrobě červených vín
Stašová, Veronika
The bachelor thesis deals with the importance of oxygen at red wine production. The first chapter is focused on the importance of oxygen, its physically-chemical pro-perties and its importance in the field of viticulture. The second chapter describes ele-mentary compounds originated from grapes. The third chapter concentrates on possible occurrence of various types of oxidation and their influence on final organoleptic pro-perties of wine. The following part of the bachelor thesis describes modern technological procedures used at wine production. The final part is oriented on positive and negative effects of oxygen on wine during the aging process in different types of tanks and classification of wooden barrels.
|
|
|
System of evaluation of soil organic matter based on fractionation by level of hydrophilic characteristics and by characterisation of fractions with differential thermic analysis
STROSSER, Eduard
The contemporary methods of evaluation of the soil organic matter do not sufficiently characterize its stability. The aim of this study is to develop a method for soil organic matter stability evaluation. The four different methods were tested, two based on chemical principle a two on microbiology principle. The first method is based on sequential soil organic matter fractionation by a system of solvents with increasing polarity, the second method uses oxidizers with different oxidizing efficiency. In the third method micro-organisms decompose soil organic matter in anaerobic environment as well as in the four method, but this one makes use of up gas production measuring sensors. The method of sequential extraction is not suitable for practical use, the oxidation method is preferred. The oxidation method also both microbiology methods imply that the most important part of soil organic matter is decomposed rapidly or while using weak oxidizer. This fraction is the most important for evaluation decomposability and it is characteristic for particular soils. After decomposition of this part of SOM its remnant is decomposed steady and linear or micro-organisms are not able to decompose it.
|
|
|
Long-Time Oxidation of gammaFe and LH15 Steel at High Temperatures in Air
Kučera, Jaroslav ; Adamaszek, K. ; Jurasz, Z.
The results of surface oxidation and decarburizatin of (Fe, C, Mn, Si, Cr, Ni) steels are reported. The oxidation anneals were carried out at temperatures T = 940, 980, 1020, 1060, 1100 oC. The time course of Fe and of steels oxidation is expressed by parabolic law. The surface oxidation is accompanied by decarburization of surface steel layers. The evaluation of measured carbon concentration profiles N(C,x,t) yields diffusion coefficients D(C,T). Oxidation coefficients kp(T) are linearly proportional to D(C,T).
|
|
|
OXIDATION OF Fe AND STEELS AT HIGH TEMPERATURES
Kučera, Jaroslav ; Adamaszek, K. ; Hajduga, M.
The results of surface oxidation and decarburization of (Fe, C, Mn, Si, Cr, Ni) steels are reported. The oxidation anneals were carried out at temperatures T = 940, 980, 1020, 1060, 1100 °C. The time course of Fe and of steels oxidation is expressed by parabolic law l = kp . The surface oxidation is accompanied by decarburization of surface steel layers. The evaluation of measured carbon concentration profiles N(C,x,t) yields diffusion coefficients D(C,T). Oxidation coefficients kp(T) are linearly proportional to D(C,T).
|
|
|
LONG-TIME OXIDATION OF .gamma.Fe AND LH15 STEEL AT HIGH TEMPERATURES IN AIR
Kučera, Jaroslav ; Adamaszek, K. ; Jurasz, Z.
The investigation of long-time oxidation of gFe and of low alloyed steel LH15 in ambient air is reported. The specimens of gFe had the form of wires with diameter f = 3.0 mm. The relative weight gain Dw/w of these specimens grows in the course of oxidation anneal due to the oxides FeO, Fe3O4, Fe2O3 formation. The weight gain is stopped at very long time period t of oxidation anneals. This phenomenon is denoted as saturation effect. The same effect was observed in the case of oxidation of specimens made from low alloyed steel LH15. The specimens had the form of cylinders with diameter .fi. = 10 mm.
|
|
| |
guest ::
