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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Obsah vybraných kovů v půdě jako indikátor kontaminace v důsledku silniční dopravy / The content of selected metals in soil as an indicator of contamination due to the road traffic

VOLAVKA, Tomáš January 2017 (has links)
The soil, as a part of ecosystem, is permanently endangered by pollution and exposed to degradation. A large share on this pollution has a human. This problem is caused mainly by industrial production, agriculture and transport. Intensive chemical maintenance is necessary during winter. It is because of better driving on the roads. Chemicals gradually soak into the soil and contaminate it. This master thesis deals with the analysis of soil samples from close proximity of road from Veseli nad Luznici to Trebon. There was analyzed the concentration of copper, sodium and zinc. Samples were collected in two depths: from 0 to 15 cm (surface sample) and 15 to 30 cm (subsurface sample). The mentioned metals were analyzed by atomic spectrometry. The measured value concentration of copper was between 2.24 mg-kg-1 and 84.35 mg-kg-1, the sodium concentration was from 11 mg-kg-1 to 1 697 mg-kg-1 and the zinc concentration was in the range of 9 mg-kg-1 526 mg-kg-1. The highest concentration of copper (84.35 mg-kg-1) was found in the subsurface sample taken from the immediate proximity of the railway in February 2017. The highest concentration of sodium (1 697 mg-kg-1) was measured near the road in February 2016. The highest concentration of zinc (526 mg-kg-1) was measured near railway in October 2015.
32

Problematika stanovení cínu v environmentálních matricích / The issue of determination of tin in environmental matrices

Bušinová, Markéta January 2012 (has links)
This diploma thesis deals with the retrieval of the content of tin in environmental media, the circulation in them and possibilities of the determination of tin in the environment. Summarizes available information on the properties of tin and its compounds, the occurrence and circulation of tin in environmental and determination of tin in environmental media, attention is paid to the determination of total tin content using method of ET-AAS. The experimental part is focused on optimization methods of determination for the ET AAS and selection of a suitable extraction procedure for determination of total tin content in soils and sediments. The best procedure for the determination of tin in the ET-AAS was applied to samples of soil, sediment and water. As the optimum matrix modifier was chosen the solution of Pd (NO3)2 in 5% ascorbic acid, the optimum pyrolysis temperature was 1400 °C and atomization temperature 2400 ° C. Neither of extraction procedures examined were found to be an appropriate procedure for the determination of tin in environmental samples and further work is necessary to optimize the method of separation.
33

Aplikace prekoncentračních/separačních technik pro stanovení platiny v životním prostředí atomovou spektrometrií / Application of preconcentration/separation techniques for the determination of platinum in the environment by atomic spectrometry

Kosárová, Hedvika January 2013 (has links)
This thesis deals with optimization of conditions for the determination of platinum by electrothermal atomic absorption spectrometry. The theoretical part describes the occurrence of platinum in different part of the environment, its physical and chemical properties, transport and bioavailability. There is also evaluated appropriate method for determination and preconcentration of platinum. The experimental part describes advance of optimize the measurement conditions for ETA-AAS, further is describes optimization of condition for SPE and work with real samples on which are applied this conditions.
34

Studium orgánů myší z inhalačních pokusů / Study of organs of mice in inhalation experiments

Vrlíková, Lucie January 2014 (has links)
The diploma thesis is devoted to study potential risks for living organisms resulting from inhalation of nanoparticles of chosen heavy metals. The main aim of this work is the investigation of organs from experimental white mice after their guided inhalation of lead nanoparticles. The samples of liver and lungs from these animals are taken in time periods during the inhalation experiments and processed by specific methods for their evaluation. After pressurized microwave assisted decomposition of selected samples of mice organs in high purity concentrated nitric acid the content of lead is determined by atomic absorption spectrometry with electrothermal atomization. Furthermore, the changes are monitored using the microscopy of histological slides stained with hematoxylin-eosin. The results of both approaches are evaluated and compared within the frame of this work.
35

Stanovení platinových kovů v půdách na území města Brna / Determination of platinum group metals in soils the city of Brno

Pavlíčková, Ivana January 2015 (has links)
The diploma thesis focuses on identifying the presence of platinum in soil samples by absorption spectroscopy. The work is divided into two parts, the theoretical part is focused on the occurrence and behavior of platinum in the environment, the fundamental chemical and physical properties of platinum, its importance in catalytic converters in cars, on solid phase extraction method and the method for the determination of atomic absorption spectrometry. The second part is the practical part, focused on the determination of the platinum amount in the soil samples in the city of Brno.
36

Stanovení obsahu kadmia v rostlinném pletivu smrku ztepilého a buku lesního po aplikaci nanočástic oxidu kademnatého. / Determination of kadmium content in plant tissue of Norway Spruce and European Beech after application of cadmium oxide nanoparticles

Svozilová, Eva January 2017 (has links)
The aim of this thesis is to monitor cadmium content in needles of Norway spruce and European beech leaves after controlled exposure to cadmium oxide nanoparticles and evaluate the potential risks of such nanoparticles to plants. Needles and leaves were harvested after a one-week and two-week exposure and prior to analysis of cadmium content, they were modified using relevant procedures. Samples were mineralized in nitric acid using pressurized microwave mineralizer and subsequently analyzed by atomic absorption spectrometry (AAS) with electrothermal atomization of cadmium content. Based on the results AAS analysis the transport of nanoparticles into the plant tissue of studied species was evaluated, comparing the content of cadmium in one week and two weeks experiment in the washed and unwashed samples of needles and leaves.
37

Speciační analýza toxikologicky významných forem arsenu v polétavém prachu s detekcí QF-AAS / The Speciation Analysis of the Toxicological Important Forms of the Arsenic in Urban Particulate Matter Samples with the Detection QF-AAS

Jelínek, Petr January 2010 (has links)
The topic of this diploma thesis was the speciation analysis of the toxicological important forms of the arsenic in urban particulate matter samples. The detection technique used in this work was atomic absorption spectrometry with quartz atomizer. Acetic acid, ammonium acetate, hydroxylamine, potassium hydroxide and sodium carbonate are recommended leaching agents for extraction of metals from urban particulate matter samples. Results of the presenting work are following: Acidic extraction reagents can be not recommended for the speciation analysis of the arsenic, because these reagents lower sensitivity of the determination of As3+ and As5+ too and destroy the quartz atomizer. Alkaline extraction reagents don't lower sensitivity of the determination of As3+ and these reagents don't destroy the atomizer, but lower sensitivity of the determination of As5+ was obtained. Recommended reagents aren't useful for extraction of the metals from urban particulate matter samples for the speciation analysis.
38

Multielementární chemická analýza popílků ze zpracování druhotných surovin olova / Multielement analysis of flue gas residues from secondary lead smelting

Šebek, Ondřej January 2014 (has links)
Multielement analysis of flue gas residues from secondary lead smelting was tested using seven decomposition methods on four different flue gas residues and certified reference materials (CRM) CPB-2 (Pb concentrate, CCRMP). The studied samples contained both silicates and also high contents of phases with Pb, primarily Pb chlorides and sulphates. Solutions prepared by various decomposition methods were analysed using ICP OES (Al, As, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Sb, Se, Si, Sn, Sr, Ti, Tl, V, Zn). Greater yields were found for most of the elements by combined decomposition (with fusion) and decomposition by sintering. Nonetheless, both methods exhibited major losses of volatile elements (As, Bi, Sb, Tl). Thus, one of these methods must always be combined with a method of decomposition in a closed system. The work also demonstrates that, for investigation of untraditional waste geological materials (e.g. flue residues from high- temperature industrial processes), it will be necessary in the future to produce new certified reference materials with anomalous chemical and mineralogical compositions, which are not currently available on the market. Laboratory extraction tests were performed on two different types of flue residues - kinetic (30 days) with ratio L/S...
39

Nový atomizátor pro AAS na principu plazmového výboje typu dielectric barrier discharge / A novel AAS atomizer based on a dielectric barrier plasma discharge

Novák, Petr January 2015 (has links)
Atomization of arsine in a novel hydride atomizer for atomic absorption spectrometry (HG-AAS) was thoroughly optimized. This plasma atomizer is based on a dielectric barrier discharge (DBD). Sensitivity and detection limit reached 0.48 s ng-1 As and 0.16 ng ml-1 As, respectively, under optimum atomization conditions (Ar discharge using a flow rate of 60 ml min-1 Ar, DBD power 17 W). Analytical figures of merit reached in DBD are comparable to those found in an externally heated quartz tube multiatomizer (MMQTA) that was chosen as a model of conventional approach to hydride atomization in HG-AAS. An extent of interferences (Se, Sb, Bi) during As determination was investigated comparing both MMQTA and DBD atomizers. The later one was found to be more resistant towards interferences. A simple preconcentration of As in a DBD atomizer was reached after oxygen introduction into the Ar plasma in the DBD resulting in analyte retention in the atomizer followed by its volatilization once the oxygen flow is switched off. Preconcentration efficiency of 100 % was reached and detection limit improvement by a factor of ten was achieved (0.01 ng ml-1 As, preconcentration period 300 s).
40

Příprava zlatých nanočástic ve vodných a organických prostředích laserovou ablací femtosekundovými pulsy, jejich charakterizace a aplikace / Preparation of gold nanoparticles in aqueous and organic media by femtosecond laser ablation, their characterization and application

Hochmann, Lukáš January 2016 (has links)
No description available.

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