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Trace Elemental Analysis of Ashes in the Combustion of the Binder Enhanced d-RDF by Inductively Coupled Plasma Atomic Emission Spectroscopy (open access)

Trace Elemental Analysis of Ashes in the Combustion of the Binder Enhanced d-RDF by Inductively Coupled Plasma Atomic Emission Spectroscopy

Incineration is an attractive solution to the problems of disposing of municipal solid wastes and supplying energy. Because up to 25 percent of the waste in refuse-derived-fuel systems is ash, the physical and chemical characteristics of ash become more and more important for its potential impacts and methods suitable for their disposal. Trace elements concentration in ash is of great interest because of its relationship to regulatory criteria under the Resource Conservation and Recovery Act (RCRA) regarding toxicity and hazards. The applications of a microwave oven sample dissolution method has been tested on a variety of standard reference materials, with reproducible and accurate results. Fourteen trace elements, As, Ba, Be, Cd, Cr, Cu, Hg, Ni, Pb, Sb, Se, Tl, V, and Zn, from the dissolved ash samples were determined by inductively coupled plasma atomic emission spectrometry.
Date: November 1988
Creator: Tai, Chia-Hui
System: The UNT Digital Library
Ion Chromatography of Soluble Cr(III) and Cr(VI) (open access)

Ion Chromatography of Soluble Cr(III) and Cr(VI)

Ion chromatography coupled with a conductivity detector was used to investigate the analysis of Cr(III) and Cr(VI) in aqueous samples. An IC methodology for Cr(III) was developed using a cation column and an eluent containing tartaric acid, ethylenediamine, and acetonitrile at pH 2.9. The detection limit of this method can reach 0.1 ppm level with good precision. Several operational parameters were evaluated during the regular use of the method. Comparison of the IC method with AA method showed good agreement between the two methods. The anion exchange column was used for Cr(VI) determination. The best results were obtained with an eluent containing sodium gluconate, borate buffer, glycerin, and acetonitrile. The retention time for the Cr207 2 - sample was 11 min. and the calibration curve was linear between 1.0 and 100 ppm.
Date: August 1988
Creator: Huang, Julie Shiong-Jiun
System: The UNT Digital Library
Elemental Analysis of Brainstem in Victims of Sudden Infant Death Syndrome (open access)

Elemental Analysis of Brainstem in Victims of Sudden Infant Death Syndrome

A brainstem-related abnormality in respiratory control appears to be one of the most compelling mechanisms for sudden infant death syndrome (SIDS). The elements calcium, copper, iron, potassium, magnesium, sodium, phosphorus, sulfur, and zinc were analyzed by inductively coupled plasma atomic emission spectroscopy in the brainstem of 30 infants who died from SIDS and 10 infants who died from other causes (control). No differences were found between SIDS and control for any element except for more calcium in the SIDS group. A multivariate analysis of the data failed to group the majority of SIDS and control subjects in different clusters. Further research is required to determine the biological significance of the higher calcium found in the SIDS group.,
Date: December 1988
Creator: Oquendo, Javier
System: The UNT Digital Library
Detector Comparison for Simultaneous Determination of Organic Acids and Inorganic Anions (open access)

Detector Comparison for Simultaneous Determination of Organic Acids and Inorganic Anions

The research reported here is a study of detector systems to determine those most suited for simultaneous organic acid, inorganic anion determination. Comparisons are made on the basis of detection limits and sensitivities for conductivity, UV/Vis, photoconductivity, and derivative conductivity detection systems. The investigation was made using a constant chromatographic system with the only variable component being the detector system. Eluant optimization conditions for each detector are reported along with tables reporting detection limits and sensitivities for each detector system. Various chromatograms are also shown to provide a visual comparison between detector results.
Date: August 1988
Creator: Pannell, Daniel K. (Daniel Kirk)
System: The UNT Digital Library
A Reinvestigation of the Kinetics and Mechanism of Ligand Exchange in Mu-(2,2,8,8-Tetramethyl-3, 7-Dithianonane)-Decacarbonylditungsten(0) (open access)

A Reinvestigation of the Kinetics and Mechanism of Ligand Exchange in Mu-(2,2,8,8-Tetramethyl-3, 7-Dithianonane)-Decacarbonylditungsten(0)

This student is interested in reinvestigating the kinetics and mechanism of the bridged compound in l,2-dichloroethane with triisopropyl phosphite and in finding the reasons why the values of competition ratio k₋₂ /k₃ in this reaction are so large.
Date: August 1988
Creator: Liao, Jing-Piin
System: The UNT Digital Library