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Contamination of soils with selected metals due to the railway transport
VONDRUŠKA, Jan
This work deals with the determination of metals in soils taken close to the railway. Copper, zinc, nickel and chromium were selected as indicators of the environment contamination. Samples were taken from three localities in South Bohemia. These localities were chosen on the basis of different types of railway tracks (electrified and nonelectrified) and different frequency of train connection. Atomic absorption spectrometry was used for the determination of the metals. An AAS Thermo Scientific iCE 3500 spectrometer served to determine individual analytes. The highest level of copper pollution was detected for samples taken close to the railway with electrified track and with high frequency of train connection. The highest Cu concentration (66.30 mg/kg) was determined in the soil sample from 20cm depth. The highest level of zinc pollution was detected for samples taken in the distance of 3 m from the railway with electrified track and with high frequency of train connection. The highest Zn concentration (641.77 mg/kg) was determined in the soil sample from 30cm depth. The highest concentrations of other metals (Ni and Cr) were detected for the railway with nonelectrified track and with low frequency of train connection. The highest concentrations of Ni and Cr were 21.89 and 54.89 mg/kg, respectively. These concentrations were obtained for samples taken close to the railway.
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OS Google Chrome - theory and practice
Plecháč, David ; Halbich, Čestmír (advisor) ; Tomáš, Tomáš (referee)
The thesis is focused on the characteristics of the key features of the operating system Google Chrome OS and on the evaluation of deployment of this operating system in practise. The theoretical part describes the purpose and philosophy of the commercial operating system Google Chrome OS and its relation with Chrome web browser. The connection with open-source projects Chromium and Chromium OS is explained. Details of application development and deployment options, in the form of virtualization and domain administration, are analysed. The practical part applies theoretical knowledge from the development of applications for Chrome OS to create thin client application for remote control of hardware sensor over the internet. This sensor is designed and built on the platform Arduino. The sensor measures the temperature and humidity of the ambient air and remote controls high-voltage switching relays. Communication over TCP/IP uses modern MQTT protocol, for which the server is configured with MQTT Broker Mosquitto.
The next section demonstrates the procedure for building a customized build of Chromium OS from the publicly provided Google source codes. Based on the evaluation of the acquired theoretical and practical knowledge, I assess the possibility of deploying the Chrome OS in private and commercial areas.
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Speciation analysis of chromium in particulate matter of urban dust
Rybínová, Marcela ; Hraníček, Jakub (referee) ; Rychlovský, Petr (advisor)
Anion-exchange chromatography with inductively coupled plasma - atomic emission spectrometry (ICP-AES) has been used for the speciation of chromium (Cr). Chromium speciation has attracted attention because of the different toxicity, Cr(III) is relatively non-toxic and Cr(VI) has been classified as a human carcinogen. The aim of the present study was to develop simple method for the speciation analysis of Cr (Cr(III) and Cr(VI)) in particulate matter of urban dust. A combination of 2% KOH + 3% Na2CO3 has been chosen as the optimal reagent for the extraction of chromium from particular matter. It was found that there was no conversion of Cr(VI) into Cr(III). The effect of separation parameters such as acidity of mobile phase was also studied. The detection limit for Cr(VI) was about 12 ng.ml-1 . Results for the determination of Cr(VI) were confirmed by the analysis of standard reference material (BCR CRM 545, Cr(VI) in welding dust loaded on a filter) with good agreement between certified (40,16 ± 0,60 μg.g-1 ) and found (37,83 ± 1,14 μg.g-1 ) values.
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OS Chrome and the Chromium project
Pelcová, Lenka ; Vaněk, Jiří (advisor) ; Masner, Jan (referee)
The topic of this bachelor thesis is Google Chrome web-based operating system and open source Chromium project. In theoretical part of the thesis, general problematics of operating systems is shortly described, followed by the development of OS Chrome, description of the system architecture, and introduction of special hardware for usage of Chrome OS
The practical part is focused on the market analysis both in the Czech Republic and globally, including future prognoses, and comparison to Windows operating systems. Through a survey, knowledge of OS Chrome among people and most frequent usage in computers and laptops is found out. A comparison between OS Chrome and Windows 8.1 is made in these tasks.
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Google Chrome OS - theory and practice
Pavelka, Martin ; Halbich, Čestmír (advisor) ; Radomír, Radomír (referee)
In my thesis, I focus on the operating system Google Chrome OS, determination of its characteristics, definition of target group of the operating system's users and comparison of available applications with those available for other operating systems. In the theoretical part, historical development of Google is analysed first, followed by the issue of Google Chrome web browser and analyse of the operating system Google Chrome OS. The practical part starts with evaluation of survey on the operating system Google Chrome OS and is followed by multi-criteria analysis of variants comparing various categories of applications available for the operating system Google Chrome OS and other operating systems, in this case represented by the operating system Microsoft Windows 8.1 and distribution of Linux operating system Ubuntu 14.04 LTS.
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OS Google Chrome - theory and practice
Dorn, Michal ; Halbich, Čestmír (advisor) ; Radomír, Radomír (referee)
Thesis deals with the operating system Google Chrome. First, the system is described (how it works, its user interface). Next there is a characteristic of applications that can be downloaded to the system and how they work. Another part is devoted to security, which consists of several elements. The end of the theoretical part is focused on Chromebooks - devices in which the operating system is sold on the market.
The practical part is firstly characterized Dart programming language, which is then used for an application. This application shows not only work with the language, but also the benefits of Google Apps. It also shows compatibility with Windows and compares these two systems.
In conclusion are described advantages and disadvantages of Chrome system and summarizes all knowledge arising from this work.
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Spectrophotometric determination of Chromium(III) with organic reagents
Nevrlá, Jana ; Komendová, Renata (referee) ; Sommer, Lumír (advisor)
The theoretical part of this master’s thesis is mainly focused on the physical and chemical properties of chromium, its toxicity and possibility of entering of various forms of chromium into the environment. There are also described the most common analytical methods for determination of chromium in water, including ways of modification and preconcentration water samples. The aim of experimental part is the optimalization and assessing the conditions spectrophotometric determination of Cr(III) by selected organic reagents (chromazurol S, eriochromcyanine R, 4-(2-thiazolylazo)resorcinol) and their comparison with the determination of total chromium, as Cr(III), using atomic absorption spectrometry with electrothermic atomization. The analytical procedure for spectrophotometric determination of chromium with chromazurol S, which was found to be most suitable and ET-AAS, were applied to real water samples.
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Chromium and chromium species cycle in environment
Nevrlá, Jana ; Sommer, Lumír (referee) ; Dočekalová, Hana (advisor)
This work focuses in the first theoretical part mainly on the possibility of entering various forms of chromium into the environment, their accumulation and transformation in environmental compartments. There are also described methods of sampling for analytical determination of chromium, the type of treatment of these samples and the most analytical methodologies for the determination of chromium in the oxidation stage III and VI. The experimental part is focused on the quantitative determination of Cr(III) and Cr(VI) in waste water, taken from the neutralizatoin station of the Chemical faculty of Brno University of Technology, by using selected spectrophotometric methods and the obtained results are compared with the results of analytical determination of total chromium by atomic absorption spectrometry.
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