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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.
311

Shale characterization using TGA, Py-GC-MS, and NMR

Gips, Jameson Parker 03 February 2015 (has links)
Many of the current analytical techniques originally developed to characterize conventional reservoir rocks and fluid cannot adequately measure shale and source rocks. An example of this is Retort, where it is not feasible to get sufficient fluid from source rock to make useful measurements. The primary interest of this thesis is the exploration of other analytical techniques, two of which are previously unused in the oil and gas industry. These are Thermal Gravimetric Analysis (TGA), Pyrolysis-Gas Chromatography-Mass Spectrometry (Py-GC-MS), and Nuclear Magnetic Resonance (NMR). The techniques proposed offer valuable insight into the properties of the rock. TGA gives accurate weight of a sample as temperature is increased, Py-GC-MS is useful for identifying exact molecules in vaporized fluid, and NMR can be used to characterize viscosity and hydrocarbon chain length. The methods using these techniques can be utilized to further confirm mineralogy of a sample, identify the fluid constituents and quantify their weight, analyze changes in a sample between two different states, and calculate the free fluid saturations of oil and gas in shales. Procedures and results for each of these are presented in this thesis to show methodology and give the reader an idea of its useful applications. / text
312

Integration of a micro-gas chromatography system for detection of volatile organic compounds

Navaei, Milad 21 September 2015 (has links)
The focus of this dissertation is on the design and micro-fabrication of an all silicon gas chromatography column with a novel two dimensional resistive heater and on its integration with an ultra-low power Thermal Conductivity Detector (TCD) for fast separation and detection of Volatile Organic Compounds (VOC). The major limitations of the current MEMS-GC column are: direct bonding of silicon to silicon, and peak band broadening due to slow temperature programming. As part of this thesis, a new gold eutectic-fusion bonding technique is developed to improve the sealing of the column. Separation of BETX, alkane mixture and VOCs were demonstrated with the MEMS GC column. The time and power required to ramp and sustain the column’s temperature are very high for the current GC columns. To reduce the time required to separate the compounds, a new temperature gradient programming heating method was developed to generate temperature gradients along the length of the column. This novel heating method refocuses eluding bands and counteracts some of the chromatographic band spreading due to diffusion resulting in an improved separation performance. A low power TCD was packaged and tested in a GC by comparison against FID for the detection of a mixture of VOCs. It demonstrated low power operation of a few milliwatts and a very fast response. The MEMS-GC was also demonstrated for rapid detection of the VOC gases released by pathogenic species of Armillaria fungus.
313

Development and Validation of a Novel Assay to Quantify D-Limonene in Human Adipose Biopsies

Miller, Jessica Anne January 2007 (has links)
d-Limonene is a lipid-soluble bioactive food component found in citrus peel. It has demonstrated strong chemopreventive effects in rodent mammary, gastric, skin, liver, and lung cancers and is correlated with a significantly reduced risk for human squamous cell skin carcinoma. Because d-limonene is fat-soluble, it may have enhanced chemopreventive activity in fatty tissues such as breast. No previous methodology to quantify d-limonene in the adipose had been developed which significantly limited d-limonene tissue distribution research. For this research, an assay to extract d-limonene from adipose tissue and quantify with GC/MS was developed and validated. Linear calibration curves were established over the range of 0.0-2,526 ng d-limonene. Extraction recovery was 80%. Satisfactory within day precision (RSD 6.75 to 9.56%) and accuracy (% difference of 2-4%) were achieved. This sensitive, accurate, and precise assay to quantify d-limonene in adipose can be used for future human or animal fatty tissue deposition studies.
314

DEVELOPMENT OF A RAPID IN SITU TRANSESTERIFICATION METHOD FOR FATTY ACID ANALYSIS IN MICROALGAE

Hall, Julie 20 April 2012 (has links)
The FAME yield from microalgae of two in situ transesterification methods were compared to a typical Folch et al. (1957) extraction followed by transesterification using the Hilditch et al. (1964) procedure. A method based on Park & Goins (1994), utilizing 0.5 N NaOH in methanol, then 14 % BCl3 in methanol, was found to be superior to a method based on Lepage & Roy (1986), utilizing acetyl chloride in methanol. The Park & Goins (1994) method was equivalent to the traditional method and was, therefore, selected for further study. In establishing the parameters of the method, water contents up to 0.55 mL were not found to inhibit the reaction within the maximum lipid load, conservatively assessed at ~1 mg. The reaction time and temperature required to produce a maximum FAME yield was 10 min at 90 °C for the BCl3-catalyzed reaction, while the NaOH-catalyzed reaction happened instantaneously at ambient temperature.
315

Development of a Method for GC/MS Analysis of PAHs and Alkylated PAHs for Use in Characterization and Source Identification of PAH Contaminated Sites

Vestlund, Hanne January 2014 (has links)
Polycyclic aromatic hydrocarbons (PAHs) are toxic and carcinogenic environmental contaminants originating from different sources; petrogenic, pyrogenic or biogenic. Depending on the source of contamination there will be different ratios of PAHs and the effects on the environment will differ. Petrogenic sources will be higher in concentration of alkyl substituted PAHs (APAHs) while pyrogenic sources will be higher in parent PAHs. In the present study a GC/MS method was developed to separate and calibrate PAHs, dibenzothiophenes and alkyl substituted PAHs in a mix containing 49 standards. The method was able to differentiate between PAHs and APAHs with the same mass number; up to six different compounds with the same mass number was separated. The developed method was used to analyse six different soil samples from various contamination sites. PAHs, APAHs and dibenzothiophenes were identified and quantified in all samples. In order to establish the source of contamination, the distribution pattern, the ratio between different PAHs, and the ratio between APAHs and parent PAHs were used. There was a higher ratio of APAHs/PAHs and a lower ratio between the parent PAHs in the soil samples from sites contaminated with oils compared to the other samples, indicating petrogenic source. / Polycykliska aromatiska kolväten (PAH) är giftiga och cancerframkallande miljögifter som härstammar från olika källor; petrogena, pyrogena eller biogena. Olika föroreningskällor kommer att ha olika förhållanden av PAH och effekterna på miljön kommer att skilja. Petrogena källor innehåller högre koncentrationer av alkylsubstituerade PAH (APAH) medan pyrogena källor kommer att ha högre koncentration av PAH. I denna studie har en GC/MS-metod utvecklats för att separera och kalibrera PAH, dibensotiofener och alkylsubstituerade PAH i en blandning innehållande 49 standarder. Metoden kunde skilja mellan PAH och alkylsubstituerade PAH med samma masstal; upp till sex olika föreningar med samma masstal särskildes. Den utvecklade metoden användes för att analysera sex olika jordprover från olika föroreningsplatser. PAH, APAH och dibensotiofener identifierades och kvantifieras i samtliga prover. För att fastställa föroreningskällan användes fördelningsmönstret för APAH och PAH, förhållandet mellan olika PAH och ration mellan APAH och PAH. Det fanns en högre kvot APAH/PAH i jordprover från områden som var förorenade med olja, vilket indikerar på petrogena föroreningskällor.
316

On-Site Sampling and Determination of Aliphatic Amines in Industrial Waste Water using SPME

Alghamdi, Talal January 2011 (has links)
In any oil production company, one of the problems that is faced on a daily basis and which sometimes hinders the operation is corrosion. In the presence of dissolved oxygen in the water inside any vessel, tank, or pipeline, the oxygen attacks the steel to form iron oxides, and this result in corrosion of the steel. To prevent this, corrosion inhibitors are added to the oil and gas streams. These chemicals are based on aliphatic amines, which are soluble in water, to form a film to coat the steel and prevent it from the oxygen attacks. As a chemist in the laboratory, filming amines residuals should be monitored and optimized in order to make sure the system is protected against corrosion and that no excess chemical remains. This is classically done by lengthy liquid-liquid extraction of filming amines followed by colorimetric determination using spectrophotometry of the extract. SPME is an easy, rapid, and solvent free extraction technique which can be easily coupled with GC for separation and quantification, and is a good candidate to be used for this job. In this thesis, an introduction about corrosion problems and how to control and monitor them in the oil and gas industry will be shared, as well as a literature review about various methods used to determine amines in different matrices, followed by a description of the SPME procedure, including its theory, modes, fibers, and method development procedures. A flow-through system was used to simulate the process of flowing streams in pipelines during oil production and to provide unlimited sample volumes, which contributes iv to simplifying the calculation of the distribution constant between fiber and solution. Two different agitation methods were compared, which are stirring and sonication, in order to optimize the extraction time profiles of analytes. A method was developed to determine amines, using a flow-through system at the lowest detection limit possible. Different parameters were examined such as variation of pH, salt addition, and sand addition. It was found that the pH of the solution has to be adjusted in order to get better sensitivity for the desired analytes. Finally, in-fiber kinetic calibration was used to calculate the concentration of solutions at a short extraction time. This was possible by applying the dominant desorption approach using the same analytes as standards in the fiber. The experiment was successful in shortening the extraction time from 3 hours to 20 minutes, with less than 20% variation in concentrations between the actual and the calculated.
317

Identifizierung und Quantifizierung von Verbindungen mit östrogener Wirkung im Abwasser

Spengler, Peter. January 2001 (has links)
Stuttgart, Univ., Diss., 2001.
318

Entwicklung und Anwendung von Methoden zur Erfassung von Pyrrolizidinalkaloiden in Honig und Pollen

Kempf, Michael January 2009 (has links)
Würzburg, Univ., Diss., 2009. / Zsfassung in engl. Sprache.
319

Amino acid analysis in biological fluids by GC-MS

Kaspar, Hannelore January 2009 (has links)
Regensburg, Univ, Diss., 2009.
320

Identifizierung und Quantifizierung von Verbindungen mit östrogener Wirkung im Abwasser

Spengler, Peter. Unknown Date (has links) (PDF)
Universiẗat, Diss., 2001--Stuttgart.

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