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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.
1

Stanovení polybromovaných difenyléterů v matricích z požářišť / Determination of polybrominated diphenylethers in matrices from fireplaces

Čechová, Eliška January 2010 (has links)
Polybrominated diphenyl ethers belong among the persistent compounds, which have been classified as priority organic pollutants. In environmental compartments are observed in the past decade. Polybrominated diphenyl ethers are detected in abiotic and biotic matrices. For this dissertation were chosen the matrixes from seats of fire, taken in various localities of the Czech Republic and Slovakia. Their analysis should demonstrate whether they in these specific matrices remain. There were examined following polybrominated diphenyl ether congeners: BDE- 28, 47, 99, 100, 153, 154, 183. For their isolation from the matrix were used three different extraction techniques, namely ultrasonic extraction, microwave extraction and pressurized solvent extraction. For the determination was chosen method of GC / ECD. In this dissertation are also described basic chemical, physical and environmental properties of BDE, including other analytical methods that can be used to determine polybrominated diphenyl ethers in environmental compartments.
2

Mass Spectrometry of Biologically Active Small Molecules : Focusing on polyphenols, alkaloids and amino acids

Spáčil, Zdeněk January 2010 (has links)
The foci of this dissertation are on advanced liquid chromatography (LC) separation and mass spectrometry (MS) techniques for the analysis of small bioactive molecules. In addition to discussing general aspects of such techniques the results from analyses of polyphenols (PPs), alkaloids and amino acids published in five appended studies are presented and discussed. High efficiency and well understood principles make LC the method of choice for separating analytes in many kinds of scientific investigations. Moreover, when LC is coupled to an MS instrument, analytes are separated in two stages: firstly they are separated and pre-concentrated in narrow bands using LC and then separated according to their mass-to-charge (m/z) ratios in the MS instrument. Some MS instruments can provide highly accurate molecular weight measurements and mass resolution allowing identification of unknown compounds based purely on MS data, thus making prior separation unnecessary. However, prior separation is essential for analyzing substances in most complex matrices – especially useful is the ultra-high performance LC (UHPLC). The advantages of using UHPLC rather than HPLC for the analysis of PPs in tea and wine were evaluated in one of the studies this thesis is based upon. The phenolic composition of red wine was also examined, using a novel LDI technique, following solid phase extraction (SPE). A class of small aromatic molecules (medicinally important alkaloids) also proved to be amenable to straightforward analysis, by thin layer chromatography (TLC) work-up followed by LDI-MS. Finally, a LC-MS method for monitoring neurotoxins (β-N-methyl-amino-L-alanine and 2,3-diaminobutyric acid) in complex biological matrices was developed and applied. Overall, the studies show that careful attention to the physicochemical properties of analytes can provide insights that can greatly facilitate the development of alternative methods to analyze them, e.g. by LDI. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: In press. Paper 5: Manuscript.</p>
3

Organohalogenové sloučeniny - kontaminanty životního prostředí / Organohalogenic compounds - contaminants of environment

Kociánová, Veronika January 2013 (has links)
Polybrominated diphenyl ethers belong to group of brominated flame retardants. Important property of these substances is their ability to reduce flammability or to prevent ignition of many products of daily use, such us televisions, carpets, mattresses and many others. Polybrominated diphenyl ethers however are characterized by high persistence and lipophility, leading to their accumulation in the environment. In recent years, concerns about the effects of organic halogen compounds on human health, suggesting their inclusion in the list of persistent organic pollutants in 2009. These contaminants are capable of long-range transport and accumulation in the environment. Therefore, the presence of polybrominated diphenyl ethers is systematically observed in the abiotic and biotic components of the environment worldwide. Their presence has been demonstrated in areas that are clearly very distant from sources of contamination. This thesis is focused on the use of gas chromatography to assess the level of contamination of selected components of the environment, especially of soil. For these purposes was used method of gas chromatography with electron capture detection mass spectrometry.
4

Méthodes de traitement du signal pour l'analyse quantitative de gaz respiratoires à partir d’un unique capteur MOX / Signal processing for quantitative analysis of exhaled breath using a single MOX sensor

Madrolle, Stéphanie 27 September 2018 (has links)
Prélevés de manière non invasive, les gaz respiratoires sont constitués de nombreux composés organiques volatils (VOCs) dont la quantité dépend de l’état de santé du sujet. L’analyse quantitative de l’air expiré présente alors un fort intérêt médical, que ce soit pour le diagnostic ou le suivi de traitement. Dans le cadre de ma thèse, nous proposons d’étudier un dispositif d’analyse des gaz respiratoires, et notamment de ces VOCs. Cette thèse multidisciplinaire aborde différents aspects, tels que le choix des capteurs, du matériel et des modes d’acquisition, l’acquisition des données à l’aide d’un banc gaz, et ensuite le traitement des signaux obtenus de manière à quantifier un mélange de gaz. Nous étudions la réponse d’un capteur à oxyde métallique (MOX) à des mélanges de deux gaz (acétone et éthanol) dilués dans de l’air synthétique (oxygène et azote). Ensuite, nous utilisons des méthodes de séparation de sources de manière à distinguer les deux gaz, et déterminer leur concentration. Pour donner des résultats satisfaisants, ces méthodes nécessitent d’utiliser plusieurs capteurs dont on connait la forme mathématique du modèle décrivant l’interaction du mélange avec le capteur, et qui présentent une diversité suffisante dans les mesures d’étalonnage pour estimer les coefficients de ce modèle. Dans cette thèse, nous montrons que les capteurs MOX peuvent être décrits par un modèle de mélange linéaire quadratique, et qu’un mode d’acquisition fonctionnant en double température permet de générer deux capteurs virtuels à partir d’un unique capteur physique. Pour quantifier précisément les composants du mélange à partir des mesures sur ces capteurs (virtuels), nous avons conçu des méthodes de séparation de sources, supervisées et non supervisées appliquées à ce modèle non-linéaire : l’analyse en composantes indépendantes, des méthodes de moindres carrés (algorithme de Levenberg-Marquardt), et une méthode bayésienne ont été étudiées. Les résultats expérimentaux montrent que ces méthodes permettent d’estimer les concentrations de VOCs contenus dans un mélange de gaz, de façon précise, en ne nécessitant que très peu de points de calibration. / Non-invasively taken, exhaled breath contains many volatile organic compounds (VOCs) whose amount depends on the health of the subject. Quantitative analysis of exhaled air is of great medical interest, whether for diagnosis or for a treatment follow-up. As part of my thesis, we propose to study a device to analyze exhaled breath, including these VOCs. This multidisciplinary thesis addresses various aspects, such as the choice of sensors, materials and acquisition modes, the acquisition of data using a gas bench, and then the processing of the signals obtained to quantify a gas mixture. We study the response of a metal oxide sensor (MOX) to mixtures of two gases (acetone and ethanol) diluted in synthetic air (oxygen and nitrogen). Then, we use source separation methods in order to distinguish the two gases, and to determine their concentration. To give satisfactory results, these methods require first to use several sensors for which we know the mathematical model describing the interaction of the mixture with the sensor, and which present a sufficient diversity in the calibration measurements to estimate the model coefficients. In this thesis, we show that MOX sensors can be described by a linear-quadratic mixing model, and that a dual temperature acquisition mode can generate two virtual sensors from a single physical sensor. To quantify the components of the mixture from measurements on these (virtual) sensors, we have develop supervised and unsupervised source separation methods, applied to this nonlinear model: independent component analysis, least squares methods (Levenberg Marquardt algorithm), and a Bayesian method were studied. The experimental results show that these methods make it possible to estimate the VOC concentrations of a gas mixture, accurately, while requiring only a few calibration points.
5

Återvinning av blandmaterial : Polyamid och Polyester

Ljungholm, Hanna, Johansson, Amanda January 2015 (has links)
Om människor fortsätter med det konsumtionsbeteende som råder idag kommer jor-den resurser ta slut. Den fossila råvaran petroleum används vanligtvis vid framställ-ning av polyester och polyamid. Petroleum har en 100 000 årlig process, vilket är en ofantlig skillnad i förhållande till den takt som det förbrukas. Därför har eventuella möjligheter att återskapa en ny filament av återvunnet syntetiskt blandmaterial un-dersökts i detta arbete. Det finns befintliga metoder för att återvinna polyester och polyamid som homogena material. Dock vid återvinning i en gemensam process av materialen får den slutliga produkten en försämrad kvalité. Mekanisk och kemisk återvinning fungerar för att framställa syntetiska filament men i dagsläget kan endast den kemiska ge likvärdig kvalité på det återvunna filamentet i förhållande till den jungfruliga. Det har hittats ett flertal separationsmetoder som antas kunna tillämpas till bland-materialet. Olika egenskaper såsom densitet, polaritet och laddningsmöjligheter kan utnyttjas för att separera polymererna. Polyester och polyamid antas kunna separe-ras, dock görs inte detta på industriell basis troligtvis på grund av kvantitet, resurser och pris. / If people continue with the present consumption behaviour, the earth´s resources will run out. The fossil raw material petroleum is normally used in the manufacture of polyester and polyamide. Petroleum has a 100 000 annual process, which is a huge difference compared to the rate at which it is consumed. Therefore, any opportunities to recreate a new fibre from recycled synthetic bland materials are studied in this work. There are existing methods to recycle polyester and polyamide as homogeneous ma-terials. However, the recovery in a joint process get the final product a degraded quality. Mechanical and chemical recycling makes it possible to produce new syn-thetic filaments, but in the current situation, the chemical will provide comparable quality of the recycled filament in relation to the virgin. Several separation methods can be applied to the blend material. Various properties such as density, polarity and charging possibilities can be used to separate polymers. Polyester and polyamide are assumed to be separated, however, is not done on an industrial basis, probably because of the quantity, resources and money.
6

Necílený screening organických polutantů ve vodách a sedimentech / Non-target screening of organic pollutants in waters and sediments

Hamalčíková, Veronika January 2011 (has links)
This master thesis deals with the potential influence of the waste dump Hrádek u Pacova and the wastewater treatment plant Brno – Modřice on surroundings using the optimized non-target screening method of organic pollutants in water and sediments. The experimental part is focused on the identification of organic compounds in samples of ground water from monitoring wells, the surface water from stream and pond and in sediment samples collected from streams in the vicinity of municipal waste dump. Organic compounds were also identified in water and sediment samples from the river Svratka near the municipal waste water treatment plant Modřice. The sequential liquid – liquid extraction was used for the isolation of organic compounds in water samples. Organic compounds in sediment samples were isolated by pressurized solvent extraction (PSE) with subsequent fractionation of the extract using column chromatography. Final analysis determination was performed using comprehensive orthogonal two-dimensional gas chromatography with mass spectrometric detection (GCxGC-TOF MS).
7

Analýza proteinů a jejich změn v biologických tkáních / Analysis of proteins and their changes in biological tissues

Kulhavá, Lucie January 2020 (has links)
(EN) Proteins are the important biologically active substances for the organism, their qualitative and quantitative composition determines thein function in the organism. Protein analysis in biological material is an important part of biological and medical research. This dissertation is focused on the optimalization of sample preparation - the biological materials - namely the pre-analytical phase of sample processing and their preparation for their own analases and also introducing new procedures in theie praparation. The conditions of individual analysis approaches were always optimized by means of one- dimensional and two-dimensional gel electrophoresis and mass spectrometry. The obtained results were statistically evaluated and other possible approaches to futher research were outlined. The main biological material studied was human saliva with regard to oral health. Comparative study of human saliva was performed (human saliva obtained from caries-free and caries-susceptible people). The saliva composition of individual fractions was investigated with regard to oral health. The study was carried out to compare differences in the abundances of proteins in the saliva of caries-free and caries-susceptible persons, based on label-free mass spectrometry quantification, and to perform a gender...
8

Kostnadseffektivisering och kvalitetsförbättring gällande hantering av skärvätska

Brosgård, Philip, Fahlman, Anna January 2015 (has links)
Projektet bestod i att ge underlag för lämpliga och användbara lösningar för effektivisering av Kockums Maskins skärvätskehantering och kostnadsrelaterade faktorer gällande företagets skärvätska. En grundlig undersökning av lämpligt material inom projektets huvudsakliga område gjordes till en början för att därefter resultera i en vidare analys av företagets nuvarande system och hantering av skärvätskor. Utifrån denna analys påbörjades en vidare undersökning om möjliga förslag om förbättring gällande de berörda problemen. Genom direktkontakt med flertalet företag och personer inom hantering/inköp samt befintlig dokumentation gällande skärvätska, erhölls ett flertal lösningar och förbättringsförslag som senare utvärderades och användes vid framtagning av det sökta projektresultatet. Problematiken gällande valet av lösningar har att göra med det faktum att det krävs omfattande kompetens inom varje typ av lösningsgrupp för att uppfylla de krav och förhållanden som finns hos Kockums Maskin. Därmed har avgränsningar gjorts gällande direkta val av lösningar för att istället ge förslag på lämpliga lösningar gällande förbättring av kvalitet, som indirekt bör sänka den årliga kostnaden av skärvätska, utifrån Kockums Maskins egentliga behov. / The project was to provide the basis for appropriate and useful solutions for any eventually streamlining of Kockums Maskin's cutting fluid management. Cost-related factors regarding the company's cutting fluid are also included in this part. A detailed examination of suitable material within the project's main area were initially and subsequently result in a further analysis of the company's existing systems and management, regarding cutting fluids. Based on this analysis a further investigation on possible proposals was started for improvement regarding the issues involved with the solutions and the cutting fluids. Through direct contact with many companies and individuals in management/purchasing and existing documentation regarding cutting fluid, obtained a several solutions and suggestions for improvement regarding the searched area. This result was then later evaluated and used in the development of the project results. The problem regarding the choice of solutions has to do with the fact that it requires extensive expertise in every type of area to meet the requirements and conditions that Kockums Maskin demands. Thus, the boundaries claimed the election of solutions to instead provide suggestions for suitable solutions regarding the improvement of quality, which indirectly should lower the annual cost of cutting fluid, based on Kockums Maskin's actual needs.
9

Porovnání vybraných metod výpočtu základního odtoku na malém povodí a zhodnocení vlivu základního odtoku na koncentrace dusíku v celkovém odtoku / Comparison of selected methods of calculating of the basic runoff in a small watershed and evaluation of the basic runoff effect to the concentrations of nitrogen in total runoff

MAIEROVÁ, Monika January 2013 (has links)
This thesis is focused on the selected methods of calculating basic runoff on a small catchment basin known as the P6, which belongs to the basin Kopaninsky flow and assess the impact on the basic runoff concentration of nitrate nitrogen in the total runoff. The thesis also analyzes the total, surface and subsurface runoff with its detailed division. There are also described in detail the chosen methods used for the separation of basic drainage. There is shown their mutual comparison too. We dealt with the nitrogen in groundwater. The methods for separation of basic runoff are described with regard to the content of nitrogen compounds, which are practically the most common type of pollution of groundwater used as drinking water sources.
10

Využití separačních metod pro studium biologicky aktivních látek ve vodách / The Usage of Separation Methods for Research of Biologically Active Substances in Waters

Vydrová, Lucie January 2011 (has links)
Pharmaceuticals are biological active compounds with different functional groups, physico-chemical and biological properties. These chemical compounds are called as “new contaminants” which cumulate in various environmental components. These contaminants input to environment from industrial processes, hospitals and health care institutions or household sources and these pollutants can to negatively interact with environmental components. Pharmaceuticals are separated according to structure and their effects to live organisms. On the basis of drug consumption in Czech Republic the non-steroidal anti-inflammatory drugs are the most using pharmaceuticals, because these drugs can be obtain without prescriptions. The choosing analgesics for study were monitored in waste water from waste waters treatment plant (WWTP Brno – Modřice) and in surface water from two sampling sites of river Kretinka. Pharmaceuticals were monitored in surface waters in Czech Republic, in Scotland (river Thurso) and in Taiwan (river Erren, Agongdian, Yanshuei and canal of Tainan) Solid phase extraction (SPE) is used for extraction of study pharmaceutical from water system. The high performance liquid chromatography (HPLC) with diode array detection or mass spectrometry was used for determination of drugs in surface waters from Czech Republic. The water samples from Scotland and Taiwan were analysed and the high performance liquid chromatography with mass spectrometry (HPLC/MS) was used for determination of pharmaceuticals. The method of HPLC/MS enables the determination of study compounds in the very low range of concentrations (ng ? l-1). All monitored pharmaceuticals were identified and quantified in water samples from river Kretinka in Czech Republic, river Thurso (Scotland) and rivers Erren, Agongdian, Yanshuei and canal of Tainan in Taiwan and the obtained data were compared.

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