Direct probing of chromatography columns by laser-induced fluorescence (open access)

Direct probing of chromatography columns by laser-induced fluorescence

This report summarizes the progress and accomplishments of this research project from September 1, 1989 to February 28, 1993. During this period, we have accomplished all of the primary scientific objectives of the research proposal: (1) constructed and evaluated a laser-induced fluorescence detection system that allows direct examination of the chromatographic column, (2) examined nonequilibrium processes that occur upon solute injection and elution, (3) examined solute retention in liquid chromatography as a function of temperature and pressure, (4) examined solute zone dispersion in liquid chromatography as a function of temperature and pressure, and (5) developed appropriate theoretical models to describe these phenomena. In each of these studies, substantial knowledge has been gained of the fundamental processes that are responsible for chromatographic separations. In addition to these primary research objectives, we have made significant progress in three related areas: (1) examined pyrene as a fluorescent polarity probe insupercritical fluids and liquids as a function of temperature and pressure, (2) developed methods for the class-selective identification of polynuclear aromatic hydrocarbons in coal-derived fluids by microcolumn liquid chromatography with fluorescence quenching detection, and (3) developed methods for the determination of saturated and unsaturated (including omega-3) fatty acids in fish oil extracts by microcolumn …
Date: December 7, 1992
Creator: McGuffin, V.L.
Object Type: Report
System: The UNT Digital Library
Direct probing of chromatography columns by laser-induced fluorescence. Technical progress report, September 1, 1989--February 28, 1993 (open access)

Direct probing of chromatography columns by laser-induced fluorescence. Technical progress report, September 1, 1989--February 28, 1993

This report summarizes the progress and accomplishments of this research project from September 1, 1989 to February 28, 1993. During this period, we have accomplished all of the primary scientific objectives of the research proposal: (1) constructed and evaluated a laser-induced fluorescence detection system that allows direct examination of the chromatographic column, (2) examined nonequilibrium processes that occur upon solute injection and elution, (3) examined solute retention in liquid chromatography as a function of temperature and pressure, (4) examined solute zone dispersion in liquid chromatography as a function of temperature and pressure, and (5) developed appropriate theoretical models to describe these phenomena. In each of these studies, substantial knowledge has been gained of the fundamental processes that are responsible for chromatographic separations. In addition to these primary research objectives, we have made significant progress in three related areas: (1) examined pyrene as a fluorescent polarity probe insupercritical fluids and liquids as a function of temperature and pressure, (2) developed methods for the class-selective identification of polynuclear aromatic hydrocarbons in coal-derived fluids by microcolumn liquid chromatography with fluorescence quenching detection, and (3) developed methods for the determination of saturated and unsaturated (including omega-3) fatty acids in fish oil extracts by microcolumn …
Date: December 7, 1992
Creator: McGuffin, V. L.
Object Type: Report
System: The UNT Digital Library
Solid state, surface and catalytic studies of oxides (open access)

Solid state, surface and catalytic studies of oxides

The properties of oxide catalysts that determine selectivity in oxidation of alkanes were investigated. Upon examining the product distribution in the oxidation of ethane, propane, butane, pentane, and cyclohexane over Mg orthovanadate, Mg pyrovanadate, and vanadyl pyrophosphate, it was found that whether dehydrogenation, formation of oxygen-containing organic products, or combustion was the predominant reaction depended on the catalyst and alkane. The product distribution could be explained by considering whether the active sites contained easily removable lattice oxygen ions, and whether the size of the alkane molecule was sufficiently large to be bonded to two adjacent vanadium ions in the active site to enhance the probability of reaction between the adsorbed hydrocarbon intermediate and reactive lattice oxygen. Selectivity for oxidative dehydrogenation of butane on silica-supported vanadium oxide depended on the vanadia loading. The selectivity was much higher on a 1 wt.% than on a 10 Wt-% V[sub 2]O[sub 5]/SiO[sub 2] sample. It was also found that on the 10 wt.% sample, agglomeration of vanadia into V[sub 2]O[sub 5] crystallites occurred during reaction. Results suggested that isolated VO[sub 4] units were more selective for dehydrogenation of butane, consistent with the idea that the selectivity depended on the availability of reactive oxygen in …
Date: December 7, 1992
Creator: Kung, H. H.
Object Type: Report
System: The UNT Digital Library
Texas Attorney General Opinion: DM-185 (open access)

Texas Attorney General Opinion: DM-185

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Dan Morales, regarding a legal question submitted for clarification; Whether a municipality may establish a program for economic development pursuant to section 380.001 of the Local Governement Code, and related questions (RQ-464)
Date: December 7, 1992
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Electrochemical processing of nitrate waste solutions (open access)

Electrochemical processing of nitrate waste solutions

The second phase of research performed at The Electrosynthesis Co., Inc. has demonstrated the successful removal of nitrite and nitrate from a synthetic effluent stream via a direct electrochemical reduction at a cathode. It was shown that direct reduction occurs at good current efficiencies in 1,000 hour studies. The membrane separation process is not readily achievable for the removal of nitrites and nitrates due to poor current efficiencies and membrane stability problems. A direct reduction process was studied at various cathode materials in a flow cell using the complete synthetic mix. Lead was found to be the cathode material of choice, displaying good current efficiencies and stability in short and long term tests under conditions of high temperature and high current density. Several anode materials were studied in both undivided and divided cell configurations. A divided cell configuration was preferable because it would prevent re-oxidation of nitrite by the anode. The technical objective of eliminating electrode fouling and solids formation was achieved although anode materials which had demonstrated good stability in short term divided cell tests corroded in 1,000 hour experiments. The cause for corrosion is thought to be F[sup [minus]] ions from the synthetic mix migrating across the cation …
Date: October 7, 1992
Creator: Genders, D.; Weinberg, N. & Hartsough, D. (Electrosynthesis Co., Inc., Cheektowaga, NY (United States))
Object Type: Report
System: The UNT Digital Library
Electrochemical processing of nitrate waste solutions. Phase 2, Final report (open access)

Electrochemical processing of nitrate waste solutions. Phase 2, Final report

The second phase of research performed at The Electrosynthesis Co., Inc. has demonstrated the successful removal of nitrite and nitrate from a synthetic effluent stream via a direct electrochemical reduction at a cathode. It was shown that direct reduction occurs at good current efficiencies in 1,000 hour studies. The membrane separation process is not readily achievable for the removal of nitrites and nitrates due to poor current efficiencies and membrane stability problems. A direct reduction process was studied at various cathode materials in a flow cell using the complete synthetic mix. Lead was found to be the cathode material of choice, displaying good current efficiencies and stability in short and long term tests under conditions of high temperature and high current density. Several anode materials were studied in both undivided and divided cell configurations. A divided cell configuration was preferable because it would prevent re-oxidation of nitrite by the anode. The technical objective of eliminating electrode fouling and solids formation was achieved although anode materials which had demonstrated good stability in short term divided cell tests corroded in 1,000 hour experiments. The cause for corrosion is thought to be F{sup {minus}} ions from the synthetic mix migrating across the cation …
Date: October 7, 1992
Creator: Genders, D.; Weinberg, N. & Hartsough, D.
Object Type: Report
System: The UNT Digital Library
The Savannah River Site`s Groundwater Monitoring Program: Second quarter 1992 (open access)

The Savannah River Site`s Groundwater Monitoring Program: Second quarter 1992

The Environmental Protection Department/Environmental Monitoring Section (EPD/EMS) administers the Savannah River Site`s (SRS) Groundwater Monitoring Program. During second quarter 1992, EPD/EMS conducted extensive sampling of monitoring wells. EPD/EMS established two sets of criteria to assist in the management of sample results. The flagging criteria do not define contamination levels; instead, they aid personnel in sample scheduling, interpretation of data, and trend identification. Since 1991, the flagging criteria have been based on the federal Environmental Protection Agency (EPA) drinking water standards and on method detection limits. A detailed explanation of the current flagging criteria is presented in the Flagging Criteria section of this document. Analytical results from second quarter 1992 are listed in this report.
Date: October 7, 1992
Creator: Rogers, C. D.
Object Type: Report
System: The UNT Digital Library
The Savannah River Site's Groundwater Monitoring Program: Second quarter 1992 (open access)

The Savannah River Site's Groundwater Monitoring Program: Second quarter 1992

The Environmental Protection Department/Environmental Monitoring Section (EPD/EMS) administers the Savannah River Site's (SRS) Groundwater Monitoring Program. During second quarter 1992, EPD/EMS conducted extensive sampling of monitoring wells. EPD/EMS established two sets of criteria to assist in the management of sample results. The flagging criteria do not define contamination levels; instead, they aid personnel in sample scheduling, interpretation of data, and trend identification. Since 1991, the flagging criteria have been based on the federal Environmental Protection Agency (EPA) drinking water standards and on method detection limits. A detailed explanation of the current flagging criteria is presented in the Flagging Criteria section of this document. Analytical results from second quarter 1992 are listed in this report.
Date: October 7, 1992
Creator: Rogers, C. D.
Object Type: Report
System: The UNT Digital Library
Texas Attorney General Opinion: LO92-062 (open access)

Texas Attorney General Opinion: LO92-062

Letter opinion issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Dan Morales, regarding a legal question submitted for clarification: Kinds of evidence a notary public may accept for the purpose of acknowledging a written instrument (ID# 16743)
Date: October 7, 1992
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: LO92-063 (open access)

Texas Attorney General Opinion: LO92-063

Letter opinion issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Dan Morales, regarding a legal question submitted for clarification: Whether a physician who monitors the treatment of a patient in an ambulance by telemetry “attends” that patient for purposes of section 6 of article 49.25 of the Code of Criminal Procedure (ID# 16514)
Date: October 7, 1992
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
A high intensity solar cell invention: The edge-illuminated vertical multi-junction (VNJ) solar cell (open access)

A high intensity solar cell invention: The edge-illuminated vertical multi-junction (VNJ) solar cell

This report contains a summary of a High Intensity Solar Cell (HI Cell) development carried out under the NIST/DOE Energy-Related Invention Program. The HI Cell, or Edge-Illuminated vertical Multi-junction Solar Cell, eliminates most major problems encountered with other concentrator solar cell designs. Its high voltage and low series resistance features make it ideally suited for efficient operation at high intensities. Computer modeling shows efficiencies near 30% at 500 suns intensity are possible with state-of-art processing. Development of a working model was largely successful before encountering an unexpected problem during the last fabrication step with the anti-reflection coating. Unfortunately, funding was exhausted before its resolution. Recommendations are made to resolve the AR coating problem and to integrate all the knowledge gained during this development into a viable prototype model. The invention will provide the technical and economic performance needed to make photovoltaic systems cost-effective for wide use.
Date: August 7, 1992
Creator: Sater, B. L.
Object Type: Report
System: The UNT Digital Library
A high intensity solar cell invention: The edge-illuminated vertical multi-junction (VNJ) solar cell. Final report (open access)

A high intensity solar cell invention: The edge-illuminated vertical multi-junction (VNJ) solar cell. Final report

This report contains a summary of a High Intensity Solar Cell (HI Cell) development carried out under the NIST/DOE Energy-Related Invention Program. The HI Cell, or Edge-Illuminated vertical Multi-junction Solar Cell, eliminates most major problems encountered with other concentrator solar cell designs. Its high voltage and low series resistance features make it ideally suited for efficient operation at high intensities. Computer modeling shows efficiencies near 30% at 500 suns intensity are possible with state-of-art processing. Development of a working model was largely successful before encountering an unexpected problem during the last fabrication step with the anti-reflection coating. Unfortunately, funding was exhausted before its resolution. Recommendations are made to resolve the AR coating problem and to integrate all the knowledge gained during this development into a viable prototype model. The invention will provide the technical and economic performance needed to make photovoltaic systems cost-effective for wide use.
Date: August 7, 1992
Creator: Sater, B. L.
Object Type: Report
System: The UNT Digital Library
Texas Parks & Wildlife News, August 7, 1992 (open access)

Texas Parks & Wildlife News, August 7, 1992

Weekly newsletter discussing natural resources, parks, hunting and fishing, and other information related to the outdoors in Texas.
Date: August 7, 1992
Creator: Texas. Parks and Wildlife Department.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Texas Register, Volume 17, Number 59, Pages 5481-5575, August 7, 1992 (open access)

Texas Register, Volume 17, Number 59, Pages 5481-5575, August 7, 1992

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.
Date: August 7, 1992
Creator: Texas. Secretary of State.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
In-Home Demonstration of the Reduction of Woodstove Emissions from the Use of Densified Logs. (open access)

In-Home Demonstration of the Reduction of Woodstove Emissions from the Use of Densified Logs.

There is a need to reduce emissions from conventional wood stoves in the short-term while stove replacement takes place over the longer term. One possible is to use fuels that would burn cleaner than cordwood. Densified fuels have been commercially available for years and offer such a possibility. The objective of this project was to evaluate the emissions and efficiency performance of two commercially available densified log types in homes and compare their performance with cordwood. Researchers measured particulate matter (PM), carbon monoxide (CO), and volatile organic matter (VOC) emissions. Both total VOC and methane values are presented. Each home used an Automated Woodstove Emissions Sampler system, developed for the EPA and Bonneville Power Administration, in a series of four week-long tests for each stove. The sequence of tests in each stove was cordwood, Pres-to-Logs, Eco-Logs, and a second, confirming test using Pres-to-Logs. Results show an average reduction of 52% in PM grams per hour emissions overall for the nine stoves using Pres-to-Logs. All nine stoves displayed a reduction in PM emissions. CO emissions were more modestly reduced by 27%, and VOCs were reduced 39%. The emissions reduction percentage was similar for both types of stoves.
Date: July 7, 1992
Creator: Barnett, Stockton G. & Bidhouse, Roger D.
Object Type: Report
System: The UNT Digital Library
In-home demonstration of the reduction of woodstove emissions from the use of densified logs (open access)

In-home demonstration of the reduction of woodstove emissions from the use of densified logs

There is a need to reduce emissions from conventional wood stoves in the short-term while stove replacement takes place over the longer term. One possible is to use fuels that would burn cleaner than cordwood. Densified fuels have been commercially available for years and offer such a possibility. The objective of this project was to evaluate the emissions and efficiency performance of two commercially available densified log types in homes and compare their performance with cordwood. Researchers measured particulate matter (PM), carbon monoxide (CO), and volatile organic matter (VOC) emissions. Both total VOC and methane values are presented. Each home used an Automated Woodstove Emissions Sampler system, developed for the EPA and Bonneville Power Administration, in a series of four week-long tests for each stove. The sequence of tests in each stove was cordwood, Pres-to-Logs, Eco-Logs, and a second, confirming test using Pres-to-Logs. Results show an average reduction of 52% in PM grams per hour emissions overall for the nine stoves using Pres-to-Logs. All nine stoves displayed a reduction in PM emissions. CO emissions were more modestly reduced by 27%, and VOCs were reduced 39%. The emissions reduction percentage was similar for both types of stoves.
Date: July 7, 1992
Creator: Barnett, S. G. & Bighouse, R. D.
Object Type: Report
System: The UNT Digital Library
Oxygen electrode reaction in molten carbonate fuel cells (open access)

Oxygen electrode reaction in molten carbonate fuel cells

Molten carbonate fuel cell system is a leading candidate for the utility power generation because of its high efficiency for fuel to AC power conversion, capability for an internal reforming, and a very low environmental impact. However, the performance of the molten carbonate fuel cell is limited by the oxygen reduction reaction and the cell life time is limited by the stability of the cathode material. An elucidation of oxygen reduction reaction in molten alkali carbonate is essential because overpotential losses in the molten carbonate fuel cell are considerably greater at the oxygen cathode than at the fuel anode. Oxygen reduction on a fully-immersed gold electrode in a lithium carbonate melt was investigated by electrochemical impedance spectroscopy and cyclic voltammetry to determine electrode kinetic and mass transfer parameters. The dependences of electrode kinetic and mass transfer parameters on gas composition and temperature were examined to determine the reaction orders and the activation energies. The results showed that oxygen reduction in a pure lithium carbonate melt occurs via the peroxide mechanism. A mass transfer parameter, D{sub O}{sup 1/2}C{sub O}, estimated by the cyclic voltammetry concurred with that calculated by the EIS technique. The temperature dependence of the exchange current density and …
Date: July 7, 1992
Creator: Appleby, A. J. & White, R. E.
Object Type: Report
System: The UNT Digital Library
Oxygen electrode reaction in molten carbonate fuel cells. Final report, September 15, 1987--September 14, 1990 (open access)

Oxygen electrode reaction in molten carbonate fuel cells. Final report, September 15, 1987--September 14, 1990

Molten carbonate fuel cell system is a leading candidate for the utility power generation because of its high efficiency for fuel to AC power conversion, capability for an internal reforming, and a very low environmental impact. However, the performance of the molten carbonate fuel cell is limited by the oxygen reduction reaction and the cell life time is limited by the stability of the cathode material. An elucidation of oxygen reduction reaction in molten alkali carbonate is essential because overpotential losses in the molten carbonate fuel cell are considerably greater at the oxygen cathode than at the fuel anode. Oxygen reduction on a fully-immersed gold electrode in a lithium carbonate melt was investigated by electrochemical impedance spectroscopy and cyclic voltammetry to determine electrode kinetic and mass transfer parameters. The dependences of electrode kinetic and mass transfer parameters on gas composition and temperature were examined to determine the reaction orders and the activation energies. The results showed that oxygen reduction in a pure lithium carbonate melt occurs via the peroxide mechanism. A mass transfer parameter, D{sub O}{sup 1/2}C{sub O}, estimated by the cyclic voltammetry concurred with that calculated by the EIS technique. The temperature dependence of the exchange current density and …
Date: July 7, 1992
Creator: Appleby, A. J. & White, R. E.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Texas Register, Volume 17, Number 51, Pages 4833-4909, July 7, 1992 (open access)

Texas Register, Volume 17, Number 51, Pages 4833-4909, July 7, 1992

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.
Date: July 7, 1992
Creator: Texas. Secretary of State.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Second annual progress report of the Millimeter Wave Cloud Profiling Radar System (CPRS) (open access)

Second annual progress report of the Millimeter Wave Cloud Profiling Radar System (CPRS)

The Cloud Profiling Radar System (CPRS) is a single antenna, two frequency (33 GHz and 95 GHz) polarimetric radar which is currently under the development at the University of Massachusetts (UMASS). This system will be capable of making four dimensional Doppler and polarimetric measurements of clouds. This report gives details about the status of the various subsystems under development and discusses current research activities.
Date: June 7, 1992
Creator: Pazmany, A. L.; Sekelsky, S. M. & McIntosh, R. E.
Object Type: Report
System: The UNT Digital Library
Second annual progress report of the Millimeter Wave Cloud Profiling Radar System (CPRS) (open access)

Second annual progress report of the Millimeter Wave Cloud Profiling Radar System (CPRS)

The Cloud Profiling Radar System (CPRS) is a single antenna, two frequency (33 GHz and 95 GHz) polarimetric radar which is currently under the development at the University of Massachusetts (UMASS). This system will be capable of making four dimensional Doppler and polarimetric measurements of clouds. This report gives details about the status of the various subsystems under development and discusses current research activities.
Date: June 7, 1992
Creator: Pazmany, A. L.; Sekelsky, S. M. & McIntosh, R. E.
Object Type: Report
System: The UNT Digital Library
Clean gasoline reforming with superacid catalysts (open access)

Clean gasoline reforming with superacid catalysts

Tasks reported on this term include optimization of chlorided Pt- alumina catalysts, testing of the optimum Pt/Cl alumina catalysts, preparation and testing of zirconia superacid catalyst. (VC)
Date: May 7, 1992
Creator: Davis, B. H.
Object Type: Report
System: The UNT Digital Library
Clean gasoline reforming with superacid catalysts. Quarterly progress report, January--March 1992 (open access)

Clean gasoline reforming with superacid catalysts. Quarterly progress report, January--March 1992

Tasks reported on this term include optimization of chlorided Pt- alumina catalysts, testing of the optimum Pt/Cl alumina catalysts, preparation and testing of zirconia superacid catalyst. (VC)
Date: May 7, 1992
Creator: Davis, B. H.
Object Type: Report
System: The UNT Digital Library
Gaseous phase coal surface modification (open access)

Gaseous phase coal surface modification

In this report, we present an improved, feasible and potentially cost effective method of cleaning and beneficiating ultrafine coal. Increased mechanization of mining methods and the need towards depyritization, and demineralization have led to an increase in the quantity of coal fines generated in recent times. For example, the amount of {minus}100 mesh coal occurring in coal preparation plant feeds now typically varies from 5 to 25% of the total feed. Environmental constraints coupled with the greatly increased cost of coal have made it increasingly important to recover more of these fines. Our method chemically modifies the surface of such coals by a series of gaseous phase treatments employing Friedel-Crafts reactions. By using olefins (ethene, propene and butene) and hydrogen chloride catalyst at elevated temperature, the surface hydrophobicity of coal is enhanced. This increased hydrophobicity is manifest in surface phenomena which reflect conditions at the solid/liquid interphase (zeta potential) and those which reflect conditions at the solid/liquid/gas interphases (contact angle, wettability and floatability).
Date: May 7, 1992
Creator: Okoh, J.M.; Pinion, J. & Thiensatit, S.
Object Type: Report
System: The UNT Digital Library