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Growth of 3D Structures Induced by Electron Beam on Ceramic Substrates
Bukvišová, Kristýna ; Čechal, Jan (referee) ; Salamon, David (advisor)
Vystaví-li se vzorek působení elektronového svazku, dojde na jeho povrchu ke strukturním změnám. Jednou z těchto změn je vertikální růst 3D struktur na keramických materiálech. V práci jsou zkoumány podmínky nutné pro takový proces. Nárůst teploty často zapříčiní povrchové změny, proto je v práci proveden výpočet ohřevu materiálu elektronovým svazkem. Dále je zkoumán vliv různých parametrů svazku na růst 3D struktur, závislost objemu a rozměrů je analyzována pomocí AFM. Výsledný odhad nárůstu teploty se pohybuje v řádech jednotek, maximálně desítek K. Výrazný objemový růst je pozorován pro nízká urychlovací napětí a malé proudy. Výška vzniklých struktur dosahuje 100 nm za minutu a je nepřímo úměrná velikosti proudu.
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Decontamination of Persons at Medical Facilites during CBR Events
Magulová, Eva ; Urbánek, Pavel (referee) ; Rosická, Zdena (advisor)
The aim of this work is the effort to bring new insight into the possibility of decontamination in healthcare facilities. In the first part are briefly explained keywords. The second part is a brief preview of the sarin attack in the Tokyo metro and the cooperation of Japanese rescue system in this event. It is followed by estimated procedure of integrated rescue system of the Czech Republic at the same event in the Czech Republic. Then is a proposal of some problems arising from improvised decontamination in the unequipped hospital and a proposal for the possible course of decontamination in a medical device.
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The study of contamination of forested areas of the Czech Republic by mercury
Trávníčková, Gabriela ; Řezáčová, Veronika (referee) ; Komendová, Renata (advisor)
This bachelor thesis deals with the issue of mercury in the environment. It focuses on determining the concentration of total mercury in edible mushrooms and in the soil in 12 localities in the Jeseníky Mountains. A single-purpose absorption spectrometer AMA 254 was used to determine the mercury content. The sites where sampling took place were divided into 6 sites with spruce stand and 6 sites with beech stand. No relationship was found between the type of stand and the amount of accumulated mercury in the mushrooms. On a representative sample of yellow-boletus mushrooms found in each locality, it was found that the higher the amount of mercury in the mushroom, the lower the amount of mercury in the soil. The fungi are therefore able to accumulate mercury from the environment. Thus, they can become a potential source of intoxication when ingested. The mobility of heavy metals in the soils depends on many soil properties (pH, carbon and sulfur content). Metals form more soluble compounds in lower pH environments. The soil pH was very low and the lower the soil pH, the higher mercury concentration in the soil. This fact could be supported by acid fallout. The relationship between the mercury content and the carbon content of the soil confirmed that carbon has the ability to bind mercury. The higher the amount of carbon in the soil, the higher the amount of mercury.
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Drinking water contamination in water supply system
Černíková, Eva ; Třasoňová, Pavla (referee) ; Ručka, Jan (advisor)
The aim of this thesis is to consider the possible causes and consequences of contamination of drinking water in the water supply system. In the introduction are general information about the problems with water supply and some new approaches to water distribution system. In the next part there are described components of the water supply system and how they work. There are also described problems of drinking water contamination in water supply system. What are the mechanisms, what causes the turbidity and which microorganisms are the most common source of infections. In the final part there are described individual cases of drinking water contamination and what were the consequences. In the beginning there is a short form to every case which provides you a quick orientation in the problem.
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Assessment of soils and sediments contamination by heavy metals in the region Jihlava river
Marek, Milan ; Adamec, Vladimír (referee) ; Doležalová Weissmannová, Helena (advisor)
This diploma thesis deals with a potential contamination of hazardous metals of soil and sediments. The metals cadmium, copper, lead and mercury were chosen, their specification, limited concentration and methods of determination are also described in thesis. City Jihlava and its surroundings were chosen for evaluating pollution of the soil and sediments in this area. In collected samples of the soil and sediments presence of copper, cadmium, lead and mercury were detected via atomic absorption spectrometry (F-AAS, ET-AAS, AMA 254). The metal pollution of soils and sediments by hazardous elements in Jihlava River and in Jihlava region was evaluated.
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The influence of mechanical alloying on contamination of powder mixtures and bulk materials
Kubíček, Antonín ; Hadraba, Hynek (referee) ; Moravčík, Igor (advisor)
This thesis deals with the influence of process parameters on the contamination level of powder materials produced by mechanical alloying (MA) technology. For this purpose austenitic stainless steel 316 L and equiatomic CoCrFeNi high-entropy alloy (HEA) were prepared by high-energy ball milling. Both materials were milled in argon and nitrogen atmospheres from 5 to 30 hours. Spark plasma sintering method (SPS) was then used for consolidation of chosen powder samples. Chemical analysis of contamination within MA was carried out using combustion analysers for determination of carbon, oxygen, and nitrogen contents after different lengths of milling. Also differences in chemical composition of powder and corresponding bulk samples were measured. The microstructure analysis using scanning electron microscopy (SEM) of both powder and bulk materials was executed with focus on oxide and carbide presence and dispersion. Increasing content of carbon with increasing milling time was observed across all measured samples. This contamination is attributed to using milling vial made of tool steel AISI D2 (containing 1,55 wt. % of carbon). Increase of carbon content within consolidation using SPS was also observed. Milling of specimens using N2 as milling atmosphere caused higher contamination level in both AISI 316 L and HEA compared to milling in argon.
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Analysis of contaminants in wheel and rail contact
Straka, Tomáš ; Galas, Radovan (referee) ; Kvarda, Daniel (advisor)
Wheel/rail contact is significantly influenced by so called third body – contaminants. Aim of this bachelor’s thesis is to analyse those contaminants in the contact and to create a brief overview. Short introduction into problem of wheel/rail contact is included, followed by description of main contaminants occurring in the contact. This thesis may be used as introduction into contamination of wheel/rail contact problem.
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Assessment of the suitability of PET flakes produced by PETKA CZ, Inc. company for the manufacture of granulates for food purposes
Šudomová, Lucie ; Kučerík, Jiří (referee) ; Čáslavský, Josef (advisor)
This thesis deals with the recycling of polyethylene terephthalate and its subsequent processing into the form of a regranulate meeting the parameters required for food use. A brief description of recycling technology, PET flake quality rating and input material contamination is provided. Additionally, legislation regarding recycling for food purposes is discussed and regranulation technologies are described. The suitability of these technologies for processing specific flake samples has been confirmed. In the experimental part, differences in the regranulate samples are compared using DSC and FT-IR. It has been found that there are no major differences between food quality samples. Tests were carried out on 200 PET bottles (bottle, label), on which the input material was divided into 16 groups. Groups that are unsuitable for recycling with this technology was defined. In addition, contaminants of the final product were examined. Their approximate composition was determined and the relationship between the labels of the bottles at the inlet and the impurities at the outlet was found. Appropriate solutions have been proposed to reduce this contamination
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Presence of heavy metals near the way Rudná
Chovanec, Petr ; Pavlovský, Jiří (referee) ; Doležalová Weissmannová, Helena (advisor)
These diploma thesis is focused on assessment of hazardous metals in soils near the road Rudná in Ostrava. Seventeen sampling sites have been chosen along this road, samples from this sites were collected in three series. The amounts of mercury, lead, copper, cadmium, zinc, vanadium and manganese were determined. There was also assessed contamination of selected sites using contamination factor and degree of contamination.
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