Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 67 for “"SFE"”.
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Near-infrared imaging of artificial enamel caries lesions with a scanning fiber endoscope
… lesions. A miniature scanning fiber endoscope (SFE) operating at near-infrared (NIR) wavelengths was developed and used in this study to test whether the device could be used to discriminate demineralized enamel from sound enamel. Varying depths of artificial enamel caries lesions were prepared …
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Supercritical fluid extraction as a sample preparation technique for the isolation of polar pharmaceutical compounds
… polarity of the supercritical fluid extraction (SFE) solvent, CO₂, causes problems when applying this technique to polar compounds. The objective of this research was to expand the applicability of SFE to include polar compounds. The first phase of this research investigated "inverse SFE", which …
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Assessing technical inefficiency in private, not-for-profit, bachelor's and master's universities in the United States using stochastic frontier estimation
… using a stochastic frontier estimation (SFE) method and to evaluate the applicability of SFE to higher education. Categories of expenditures were utilized to create a production frontier against which the inefficiency of individual institutions to produce degreed students was measured. …
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Supercritical Fluid Extraction Directly Coupled with Reversed Phase Liquid Chromatography for Quantitative Analysis of Analytes in Complex Matrices
… coupling of Supercritical Fluid Extraction (SFE) with High Performance Reversed Phase Liquid Chromatography (HP-RPLC), and to explore its ability for quantitative analysis of analytes in different matrices. First, a simple interface was developed via a single one six-port injection valve to …
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Spectral finite element modelling and damage identification of beam-like structures using linear and nonlinear guided waves
… the efficient spectral finite element (SFE) method is used to simulate the guided wave propagation in beams for both isotropic and composite materials. An SFE crack element is developed to simulate crack-wave interaction and the guided wave mode-conversion effect resulted from an …
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Investigation of Liquid Trapping Following Supercritical Fluid Extraction
Supercritical fluid extraction (SFE) is an alternative to traditional extractions with organic solvents. SFE consists of removing the analyte(s) from the matrix, solubilizing them, moving the analyte(s) into the bulk fluid, and sweeping the fluid containing the analyte(s) out of the extraction …
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Supercritical fluid extraction/chromatography and Fourier transform infrared spectrometry: methods optimization and applications
… the use of supercritical fluid extraction (SFE)as a sample introduction technique for supercritical fluid chromatography (SFC) and Fourier transform infrared spectrometry (FT-IR). In order to study the effects of a supercritical mobile phase on the resulting IR spectra, carbon dioxide was …
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The extraction of analytes from aqueous solution using supercritical fluids
Supercritical fluid extraction (SFE) is becoming an attractive alternative to conventional solvent extraction for many reasons. These reasons include advantages of speed, the ability to be automated more easily than conventional solvent extractions and the lack of solvent disposal after the …
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Investigation of the supercritical fluid extraction and detection of metals in contaminated soils
In this work the Supercritical Fluid Extraction (SFE) and detection of sorbed metals in contaminated soils is explored. Iron containing samples were spiked onto sea sand and extracted with Supercritical Fluid CO₂. On-line detection was accomplished by decompressing the SF-CO₂ and analyte into a …
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The marine biogeochemistry of dissolved and colloidal Iron
… size partitioning of dFe (<0.2μm) into soluble (sFe<0.02μm) and colloidal (0.02μm<cFe<0.2μm) size fractions. This was accomplished through the measurement of the dFe distribution and size partitioning along basin-scale transects experiencing a range of biogeochemical influences. dFe provenance …
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The marine biogeochemistry of dissolved and colloidal iron
… size partitioning of dFe (<0.2 jm) into soluble (sFe<0.02 jm) and colloidal (0.02ptm<cFe<0.2 m) size fractions. This was accomplished through the measurement of the dFe distribution and size partitioning along basin-scale transects experiencing a range of biogeochemical influences. dFe provenance …
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Quantitative Analysis of Additives in Low Density Polyethylene Using On-line Supercritical Fluid Extraction /Supercritical Fluid Chromatography
… an on-line Supercritical Fluid Extraction (SFE)/Supercritical Fluid Chromatography (SFC) system was assembled to provide efficient extraction and separation of polymer additives with quantitative results. The effects of various SFE/SFC parameters, such as trapping temperature, injection …
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The Fractionation of Crude Petroleum using Chromatography, Extrography and Supercritical Fluid Extraction
… These studies have shown that under optimized SFE conditions (density 0.75 g.cm"3 and temperature 40 °C ) crude oil can be selectively fractionated into saturated and aromatic compounds.<br/> <br/>Comparatively, it was found that SFE provided an effective extraction within 56 minutes while the …
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Hyphenated fourier transform infrared spectrometry: techniques for separations and analysis
… involving supercritical fluid extraction (SFE), supercritical fluid chromatography (SFC), and liquid chromatography (LC). Three studies are presented. The first involves the application of SFE/FT-IR towards the extraction of finishes from textile fibers. SFE has previously been applied to …
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Analysis of Fats and Fat-Soluble Components in Foods Using Supercritical Fluid Extraction and Chromatographic Techniques
… the extraction of fats from common foods using SFE and to determine by chromatographic techniques the fat-soluble components that are extracted with the fats. In this study various food samples were examined including french fries from Wendy's, McDonald's and Burger King, as well as potato …
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Determination of Extractables from Cranberry Seeds Using Supercritical CO₂
… provided. The supercritical fluid extraction (SFE) operating conditions such as extraction temperature, pressure of CO2, extraction time, and CO2 flow rate were optimized to maximize the extraction yield. The amount and type of SF extractables (pure CO₂) have been compared with Soxhlet …
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Coupled solid phase extraction-supercritical fluid extraction on-line gas chromatography of explosives from water
… due to analyte break through, and not from poor SFE recoveries. This demonstrates that supercritical fluid extraction is a suitable elution technique for analytes trapped on solid phase extraction (SPE) cartridges. A method has also been developed and evaluated for the direct on-line coupling of …
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Mechanical and surface free energy characterization of asphalt concrete for moisture damage detection
… dynamic modulus tests. The surface free energy (SFE), direct adhesion test (DAT) and blister test (BT) represent the component-level types. Samples for the mixture-level tests were prepared at different aging and conditioning durations. Aging durations include one hour and four hours after mixing …
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Supercritical fluid extraction of non-traditional matrices
Supercritical extraction (SFE) has most often been linked to the use of modified or unmodified CO₂ for the recovery of relatively non-polar analytes from solid matrices. The objective of this research was to expand current supercritical fluid (SF) techniques to the recovery of analytes from …
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