Chemically modified electrodes and related solution studies (open access)

Chemically modified electrodes and related solution studies

This report is divided into 5 sections: Ru[sub 4]/Fe complexes of tetra(4[prime]-methyl-2,2[prime]-bipyridine)porphyrin--catalytic epoxidation of olefins; water oxidation catalysis by doubly linked [mu]-oxo ruthenium complexes; polymer films formed by oxidation of transition metal electrodes into solutions of bisbipyridinealkane ligands; polymer films containing [CpMo([mu]-S)][sub 2]S[sub 2]CHR dinuclear clusters;and conducting polymer films for catalyst incorporation.
Date: April 1, 1993
Creator: Elliott, C.M.
System: The UNT Digital Library
Chemically modified electrodes and related solution studies. Final technical report, January 15, 1991--January 14, 1992 (open access)

Chemically modified electrodes and related solution studies. Final technical report, January 15, 1991--January 14, 1992

This report is divided into 5 sections: Ru{sub 4}/Fe complexes of tetra(4{prime}-methyl-2,2{prime}-bipyridine)porphyrin--catalytic epoxidation of olefins; water oxidation catalysis by doubly linked {mu}-oxo ruthenium complexes; polymer films formed by oxidation of transition metal electrodes into solutions of bisbipyridinealkane ligands; polymer films containing [CpMo({mu}-S)]{sub 2}S{sub 2}CHR dinuclear clusters;and conducting polymer films for catalyst incorporation.
Date: April 1, 1993
Creator: Elliott, C. M.
System: The UNT Digital Library
Diosmacycloalkanes as models for the formation of hydrocarbons from surface methylenes (open access)

Diosmacycloalkanes as models for the formation of hydrocarbons from surface methylenes

The report is divided into: vibrational models for surface ethylidenes (on catalyst surfaces); alpha vs beta hydrogen elimination in formation of propene from an osmacyclobutane; mechanism of formation and fragmentation of diosmacyclobutanes; reaction of dienes and allenes with diosmacyclobutanes; structure of Os(CO)[sub 4](C[sub 2]H[sub 4]), an osmacyclopropane; and reaction of [mu]-oxobis [(trifluoromethanesulfanato) (phenyl)iodine(III)] with Group 14 propargyl derivatives and a propargyl ether. 16 refs, figs.
Date: May 1, 1993
Creator: Norton, J.R.
System: The UNT Digital Library
Diosmacycloalkanes as Models for the Formation of Hydrocarbons From Surface Methylenes. Progress Report, November 1, 1992--October 31, 1993 (open access)

Diosmacycloalkanes as Models for the Formation of Hydrocarbons From Surface Methylenes. Progress Report, November 1, 1992--October 31, 1993

The report is divided into: vibrational models for surface ethylidenes (on catalyst surfaces); alpha vs beta hydrogen elimination in formation of propene from an osmacyclobutane; mechanism of formation and fragmentation of diosmacyclobutanes; reaction of dienes and allenes with diosmacyclobutanes; structure of Os(CO){sub 4}(C{sub 2}H{sub 4}), an osmacyclopropane; and reaction of {mu}-oxobis [(trifluoromethanesulfanato) (phenyl)iodine(III)] with Group 14 propargyl derivatives and a propargyl ether. 16 refs, figs.
Date: May 1, 1993
Creator: Norton, J. R.
System: The UNT Digital Library
Photoinduced Charge Separation in Linked Donor-Chromophore-Acceptor Systems (open access)

Photoinduced Charge Separation in Linked Donor-Chromophore-Acceptor Systems

Focus has been mainly on preparation and characterization of triply bridged dinuclear complexes containing a tris-2-2'- bipyridineruthenium chromophore and a second tris-bipyridine metal complex which is to serve as electron donor or acceptor, and of linked RuL[sub 3]-containing D-C-A complexes where D is a phenothiazine donor and A is a diquat type acceptor. (DLC)
Date: June 1, 1993
Creator: Elliott, C.M.
System: The UNT Digital Library
Photoinduced Charge Separation in Linked Donor-Chromophore-Acceptor Systems. Progress Report, September 1, 1993--May 31, 1993 (open access)

Photoinduced Charge Separation in Linked Donor-Chromophore-Acceptor Systems. Progress Report, September 1, 1993--May 31, 1993

Focus has been mainly on preparation and characterization of triply bridged dinuclear complexes containing a tris-2-2`- bipyridineruthenium chromophore and a second tris-bipyridine metal complex which is to serve as electron donor or acceptor, and of linked RuL{sub 3}-containing D-C-A complexes where D is a phenothiazine donor and A is a diquat type acceptor. (DLC)
Date: June 1, 1993
Creator: Elliott, C. M.
System: The UNT Digital Library
Development of a gas-to-particle conversion model for use in three-dimensional global sulfur budget studies. Final report, 1 August 1991--30 June 1992 (open access)

Development of a gas-to-particle conversion model for use in three-dimensional global sulfur budget studies. Final report, 1 August 1991--30 June 1992

A fully-parameterized model for the formation and growth of aerosols via gas-to-particle conversion has been developed and tested. A particularly significant contribution is a new method for the prediction of numbers of particles nucleated using information on the vapor source rate, relative humidity, and preexisting aerosol alone, thus eliminating the need to solve a system of coupled ODEs. Preliminary tests indicate substantial reduction in computational costs, but it is recommended that the BIMODAM model be incorporated into a large-scale model of the sulfur cycle in order to more fully test its computational feasibility.
Date: August 1, 1993
Creator: Kreidenweis, S. M.
System: The UNT Digital Library
Chemically Assisted in Situ Recovery of Oil Shale. [Quarterly] Report, April 1, 1993--June 30, 1993 (open access)

Chemically Assisted in Situ Recovery of Oil Shale. [Quarterly] Report, April 1, 1993--June 30, 1993

The objective of this work is to investigate, in the laboratory, the parameters associated with a chemically assisted in situ recovery procedure, using hydrogen chloride (HCI), carbon dioxide (CO{sub 2}), and steam (H{sub 2}0), to obtain data useful to develop a process more economic than existing processes and to report all findings. The technical progress of the project is reported. The project status is that the progress is being made towards being able to run meaningful experiments.
Date: September 1, 1993
Creator: Ramirez, W. F.
System: The UNT Digital Library
Direct Methane Conversion to Methanol. Annual Report, October 1, 1992--September 30, 1993 (open access)

Direct Methane Conversion to Methanol. Annual Report, October 1, 1992--September 30, 1993

We proposed to demonstrate the effectiveness of a catalytic membrane reactor (a ceramic membrane combined with a catalyst) to selectively produce methanol by partial oxidation of methane. Methanol is used as a chemical feedstock, gasoline additive, and turbine fuel. Methane partial oxidation using a catalytic membrane reactor has been determined as one of the promising approaches for methanol synthesis from methane. In the original proposal, the membrane was used to selectively remove methanol from the reaction zone before carbon oxides form, thus increasing the methanol yield. Methanol synthesis and separation in one step would also make methane more valuable for producing chemicals and fuels. The cooling tube inserted inside the membrane reactor has created a low temperature zone that rapidly quenches the product stream. This system has proved effective for increasing methanol selectivity during CH{sub 4} oxidation. The membranes broke during experiments, however, apparently because of the large radial thermal gradient and axial thermal expansion difference. Our efforts concentrated on improving the membrane lifetime by modifying this non-isothermal membrane reactor.
Date: October 1, 1993
Creator: Noble, R. D. & Falconer, J. L.
System: The UNT Digital Library
Grassland/Atmosphere Response to Changing Climate: Coupling Regional and Local Scales. Final Report (open access)

Grassland/Atmosphere Response to Changing Climate: Coupling Regional and Local Scales. Final Report

The objectives of the study were: to evaluate the response of grassland ecosystems to atmospheric change at regional and site scales, and to develop multiscaled modeling systems to relate ecological and atmospheric models with different spatial and temporal resolutions. A menu-driven shell was developed to facilitate use of models at different temporal scales and to facilitate exchange information between models at different temporal scales. A detailed ecosystem model predicted that C{sub 3} temperate grasslands wig respond more strongly to elevated CO{sub 2} than temperate C{sub 4} grasslands in the short-term while a large positive N-PP response was predicted for a C{sub 4} Kenyan grassland. Long-term climate change scenarios produced either decreases or increases in Colorado plant productivity (NPP) depending on rainfall, but uniform increases in N-PP were predicted in Kenya. Elevated CO{sub 2} is likely to have little effect on ecosystem carbon storage in Colorado while it will increase carbon storage in Kenya. A synoptic climate classification processor (SCP) was developed to evaluate results of GCM climate sensitivity experiments. Roughly 80% agreement was achieved with manual classifications. Comparison of lx and 2xCO{sub 2} GCM Simulations revealed relatively small differences.
Date: October 1, 1993
Creator: Coughenour, M. B.; Kittel, T. G. F.; Pielke, R. A. & Eastman, J.
System: The UNT Digital Library
Baseline Risk Assessment of Groundwater Contamination at the Uranium Mill Tailings Site Near Gunnison, Colorado (open access)

Baseline Risk Assessment of Groundwater Contamination at the Uranium Mill Tailings Site Near Gunnison, Colorado

This Baseline Risk Assessment of Groundwater Contamination at the Uranium Mill Tailings Site Near Gunnison, Colorado evaluates potential impacts to public health or the environment resulting from groundwater contamination at the former uranium mill processing site. The tailings and other contaminated material at this site are being placed in an off-site disposal cell by the US Department of Energy`s (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating groundwater contamination. This is the second risk assessment of groundwater contamination at this site. The first risk assessment was performed primarily to evaluate existing domestic wells. This risk assessment evaluates the most contaminated monitor wells at the processing site. It will be used to assist in determining what remedial action is needed for contaminated groundwater at the site after the tailings are relocated. This risk assessment follows an approach outlined by the US Environmental Protection Agency (EPA). The first step is to evaluate groundwater data collected from monitor wells at the site. Evaluation of these data showed that the main contaminants in the groundwater are cadmium, cobalt, iron, manganese, sulfate, uranium, and some of the products of radioactive decay of uranium.
Date: December 1, 1993
Creator: unknown
System: The UNT Digital Library
Economic Impact Study of the Uranium Mill Tailings Remedial Action Project in Colorado: Colorado State Fiscal Year 1993 (open access)

Economic Impact Study of the Uranium Mill Tailings Remedial Action Project in Colorado: Colorado State Fiscal Year 1993

The Colorado economic impact study summarizes employment and economic benefits to the state from activities associated with the Uranium Mill Tailings Remedial Action (UMTRA) Project during Colorado state fiscal year 1993 (July 1, 1992, through June 30, 1993). To capture employment benefits, a questionnaire was distributed to subcontractor employees at the active UMTRA Project sites of Grand Junction, Rifle, and Gunnison, Colorado. An estimated 52 percent of the employees working on the UMTRA Project responded to this information request. Economic data were requested from each site prime subcontractor, as well as from the Remedial Action Contractor. The most significant benefits associated with the UMTRA Project in Colorado are summarized.
Date: December 1, 1993
Creator: unknown
System: The UNT Digital Library