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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.
181

Stanovení organických sloučenin v dehtu po spalování a zplyňování biomasy / Determination of organic substances in tar formed after biomass combustion and gasification

Hájek, Radek January 2015 (has links)
Biomass pyrolysis and gasification techniques count among basic technological procedures for its use as a source of energy. As a side-effect, production of tar can be considered. Tar is a complex mixture of various organic compounds and affects negatively both the environment and the facilities where biomass is processed. Within the scope of this master thesis the analysis of tar samples from different materials was performed. As an appropriate analytical method the gas chromatography combined with flame ionization detection (GC-FID) and time-of-flight mass spectrometry (GC-TOF-MS) was chosen. The concentrations of volatile organic compounds known as BTEX, polycyclic aromatic hydrocarbons (PAH) and phenolic compounds were assessed.
182

Stanovení léčiv v pitných vodách metodou HPLC / Determination of pharmaceuticals in drinking waters using HPLC

Králová, Radka January 2015 (has links)
The aim of the diploma thesis is the determination of macrolide antibiotics in drinking water by using of high performance liquid chromatography. Erythromycin and clarithromycin were selected such as representative macrolides due to frequently prescribed pharmaceuticals in this time. Solid phase extraction (SPE) by using of Oasis HLB cartridges was applied for pre concentration and purification of chosen analytes in real samples of drinking water. Optimalization of method and analysis were performed by using of high performance liquid chromatography with mass spectrometry detection (HPLC-MS). The suitable method was selected for determination of macrolides in real samples taken from two sources of drinking water, the interception of water in Litovel and Černovír Olomouc.
183

Stabilita aprotických elektrolytů v lithno-iontových akumulátorech / Stability of aprotic electrolytes in lithium-ion batteries

Krištofík, František January 2014 (has links)
The Master thesis describe basic electrochemical processes in lithium-ion batteries and characteristic organic polar solvents for these articles. It focuses primarily on the aprotic liquid electrolytes for lithium-ion batteries and the subsequent use of gas chromatography to analyze the collected gas sample from the test article. For this experiment is, in this Master thesis, designed and described experimental arrangement in the form of a glass cell, which allows collection from the space above the working electrode. Finally, the work evaluates the effect of electrode potential on the stability of electrolytes in strongly positive potentials.
184

Využití separačních technik na bázi plynové a kapalinové chromatografie s různým typem detektorů pro stanovení biologicky aktivních látek a vybraných xenobiotik / The Application of Separation Techniques Based on Gas and Liquid Chromatography with Different Types of Detectors for the Determination of Biologically Active Compounds and Selected Xenobiotics

Mravcová, Ludmila January 2011 (has links)
This work deals with the using and application of separation techniques for analysis of polymers degradation and polycyclic aromatic hydrocarbons. Thereby this work is separated to two special parts. In the first part, the degradation properties of synthetic biopolymers based on lactic acid, gylcolic acid and poly(ethyleneglycol) PLGA-PEG-PLGA and ITA-PLGA-PEG-PLGA-ITA (modified by itaconic acid) were studied. These copolymers (firstly their thermosensitive hydrogels) should be used for therapy of fractures in orthopedy (as adhesives). Therefore, the sol-gel and gel-sol phase diagrams were determinated for selected samples of copolymers. The samples forming gel at 37 C was used for other study. Polymer samples were depredated in phosphate buffer at 37°C. The degradation process of physical hydrogels was described by the decrease of molecular weight and the increase of concentration lactic acid and glycolic acid in phosphate buffer. The obtained results confirmed that the degradation of polymer modified by itaconic acid is faster process than no modified polymer and polymers with lower ratio PLGA/PEG degrade also faster than lower ration PLGA/PEG. The influence of pH it was also tested. The rate of degradation of polymers was follow pH 4,0
185

Studium vlivu požárů skládek komunálních a průmyslových odpadů na kontaminaci životního prostředí, produkty hoření pryže a halogenovaných polymerů / Study of the influence of fires of municipal and industrial waste landfills on the enviromental contamination, the combustion products of rubber and halogenated polymers

Sikora, Henryk January 2014 (has links)
This thesis deals with the issue of fires of municipal and industrial wastes, particularly of rubber and halogenated polymers. When these materials burn, significant amount of harmful substances liberate into environmental compartments. Analysis of samples subjected to thermal decomposition in laboratory conditions explored formation of characteristic compounds in dependence on conditions of combustion. Samples of air, water and soil taken from real fires that occurred between the years 2007 – 2011 in the region of Western Bohemia monitored spreading of these substances into the environment. Majority of these samples were analysed by the means of gas chromatography with mass spectrometric detection. Additionally the effect of extinguishing methods and use of fire extinguishers on formation and spreading of combustion products was studied, especially in soil and in water sources.
186

Alergenní vonné látky v potravinách a předmětech běžného užívání / Fragrance Allergens in Foods and Everyday Use Products

Divišová, Radka January 2014 (has links)
Fragrances are added to food, cosmetics and other products primarily for enhancement of their sensory quality (taste and/or aroma). However, the usage of these compounds is associated with the wide range of various adverse biological effects. Some fragrances widely used in cosmetics are proved to cause e.g. skin sensitization, rashes, dermatitis, headache, cough etc. To protect the health of consumers, European union approved the cosmetic directive (ES/1223/2009) that requires the labeling of 26 allergen fragrances on the final product label, if concentration exceeds the given level (0,01 % for rinse-off and 0,001 % for leave-on product). However, some producers hide the presence of allergens in the final product under the general term „aroma“. For this reason it is very important to monitor the content of these substances in cosmetic products. Fragrances are found not only in cosmetics, but the various types of food are also aromatized by them. Unlike cosmetics, the food producers are not obliged to label the presence of fragrance allergens on the packaging. Therefore, the monitoring of these fragrances is highly desirable because of the potential health risks they pose. The aim of this study was to develop a method for simultaneous determination of regulated fragrance allergens in food and everyday use products. The method based on extraction of analytes by solid phase microextraction coupled to gas chromatography with FID detection (HS-SPME-GC-FID) was chosen on the basis of the literature review. The fiber CAR/PDMS provided the highest extraction efficiency among the SPME fibers tested. Univariate and multivariate data analysis were used to optimize the main parameters affecting microextraction process. The final method validation was performed in terms of linearity, repeatability, reproducibility, recovery, limits of detection and quantification. The optimized and validated method was applied to a wide range of products including cosmetics, aromatized food and fragranced toys. These products were also subjected to sensory evaluation especially in terms of taste and/or aroma (i.e. flavour), which may be associated with the content of the monitored fragrances. The profile test (EN ISO 13299) and seven-point category ordinal scale (ISO 4121) were used for sensory evaluation.
187

Vliv technologických procesů na obsah prioritních kontaminantů v čistírnách odpadních vod / Influence of technological processes on the content of priority contaminants in wastewater treatment plants

Mikulíková, Iva January 2016 (has links)
Water is one of the most abundant substances on Earth and it is an essential part of our lives. Its pollution has an impact on the whole ecosystem. Polybrominated diphenyl ethersare synthetic persistent organic pollutants used as flame retardants in various commercial and household products. This thesis is focused on assesing the degree of elimination of PBDEs in wastewater treatment plants with different technological processes of purification. The samples were collected in the three wastewater treatment plants in the south-moravian region, that means WTP Brno – Modřice, WTP Mikulov and WTP in VFU Brno.
188

Stanovení makrolidů v odpadních vodách v průběhu technologií aplikovaných na čistírnách odpadních vod / Determination of macrolides in wastewater during the technology applied to wastewater treatment plants

Landová, Pavlína January 2016 (has links)
Diploma thesis is focused on determination of macrolide antibiotics in wastewater. Environmental contamination with drugs currently represents a major problem. To determine the level of contamination is necessary to develop the appropriate analytical techniques. From the group of macrolide antibiotics were selected four representatives: erythromycin, clarithromycin, azithromycin and roxithromycin due to their frequent use in Czech Republic. For their isolation from wastewater was selected solid phase extraction and for analysis high performance liquid chromatography with mass spectrometric detection was chosen. Under optimized conditions, the ten days analysis of wastewater from the WWTP Brno-Modřice, two days analysis of wastewater from the WWTP Mikulov and one day analysis of wastewater from WWTP of University of Veterinary and Pharmaceutical Sciences Brno was performed.
189

Charakterizace chemického složení dehtu po zplyňování biomasy / Characterization of the chemical composition of the tar produced in the gasification of biomass

Mahelová, Zora January 2016 (has links)
Biomass is a renewable source of energy and represents an acceptable alternative to fosil fuels. Usable methods of energetic use of biomass are combustion and gasification. Main interest is focused on gasification in last years. Gasification is based on conversion of organic material to usable gaseous product called syngas, which can be used as a fuel for energy production. Large amount of tar is formed as a by-product of incineration and gasification of biomass. Tar is composed by various mixture of organic substances, has a negative effect on operating conditions and is a potential threat to environment. Experimental part of this study was focused on analysis of tar obtained by gasification of various kind of biomass. Selected groups of hydrocarbons and oxygen compounds were identified in analysed samples. Individual biomass samples were compared regarding to determined relative content of selected substances. Analysis was done by complete twodimensional gas chromatography with mass spectrometric detection (GCxGC/TOF-MS).
190

Studium předúpravy a následné hydrolýzy vybraných lignocelulózových materiálů / Study on pretreatment and hydrolysis of selected lignocellulose materials

Kovářová, Markéta January 2017 (has links)
This diploma thesis is focused on study of chemical and enzymatical hydrolysis of raw wood material. The aim of this work was to find the suitable method for pretreatment of selected lignocellulose materials. The theoretical part deals with characterization of lignocellulosic material and its components. There are also subscribed various pretreatment methods and their effect on hydrolysis of sawdust. In experimental part of the work the most appropriate approach of pretreatment and hydrolysis of sawdust was studied. Criteria for the selection of suitable method was concentration of saccharides as desired product of hydrolysis and also concentration of the most important microbial inhibitors - polyphenols. Application of 96% ethanol or 5% H2O2 were identified as the most promising pretreatment methods which enhanced yields of fermentable sugars about 30 %. Further, we also performed cultivation of bacteria Burkholderia cepacia and bacteria Burkholderia sacchari using solution obtained by hydrolysis of lignocellulose material.

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