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Coal and Coal Constituent Studies by Advanced EMR Techniques

Description: Advanced electronic magnetic resonance (EMR) methods are used to examine properties of coals, chars, and molecular species related to constituents of coal. We have achieved substantial progress on upgrading the high field (HF) EMR (W-band, 95 GHz) spectrometers that are especially advantageous for such studies. Particularly, we have built a new second W-band instrument (Mark II) in addition to our Mark I. Briefly, Mark II features: (i) an Oxford custom-built 7 T superconducting magnet which is scannable from 0 to 7 T at up to 0.5 T/min; (ii) water-cooled coaxial solenoid with up to ±550 G scan under digital (15 bits resolution) computer control; (iii) custom-engineered precision feed-back circuit, which is used to drive this solenoid, is based on an Ultrastab 860R sensor that has linearity better than 5 ppm and resolution of 0.05 ppm; (iv) an Oxford CF 1200 cryostat for variable temperature studies from 1.8 to 340 K. During this grant period we have completed several key upgrades of both Mark I and II, particularly microwave bridge, W-band probehead, and computer interfaces. We utilize these improved instruments for HF EMR studies of spin-spin interaction and existence of different paramagnetic species in carbonaceous solids.
Date: March 31, 1998
Creator: Smirnov, Alex I.; Nilges, Mark J.; Belford, R. Linn & Clarkson, Robert B.
Partner: UNT Libraries Government Documents Department

Pressure Gradient Passivation of Carbonaceous Material Normally Susceptible to Spontaneous Combustion

Description: This invention is a process for the passivation or deactivation with respect to oxygen of a carbonaceous material by the exposure of the carbonaceous material to an oxygenated gas in which the oxygenated gas pressure is increased from a first pressure to a second pressure and then the pressure is changed to a third pressure. Preferably a cyclic process which comprises exposing the carbonaceous material to the gas at low pressure and increasing the pressure to a second higher pressure and then returning the pressure to a lower pressure is used. The cycle is repeated at least twice wherein the higher pressure may be increased after a selected number of cycles.
Date: July 15, 1999
Creator: Ochs, Thomas L.; Sands, William D.; Schroeder, Karl; Summers, Cathy A. & Utz, Bruce R.
Partner: UNT Libraries Government Documents Department

Pressure gradient passivation of carbonaceous material normally susceptible to spontaneous combustion

Description: This invention is a process for the passivation or deactivation with respect to oxygen of a carbonaceous material by the exposure of the carbonaceous material to an oxygenated gas in which the oxygenated gas pressure is increased from a first pressure to a second pressure and then the pressure is changed to a third pressure. Preferably a cyclic process which comprises exposing the carbonaceous material to the gas at low pressure and increasing the pressure to a second higher pressure and then returning the pressure to a lower pressure is used. The cycle is repeated at least twice wherein the higher pressure may be increased after a selected number of cycles.
Date: January 29, 2002
Creator: Ochs, Thomas L.; Sands, William D.; Schroeder, Karl; Summers, Cathy A. & Utz, Bruce R.
Partner: UNT Libraries Government Documents Department

Phase reference materials for photoacoustic spectroscopy

Description: Interest in the phase of photoacoustic signals has increased greatly since the advent of phase modulation in FTIR spectroscopy. The photoacoustic phase provides information on the depth of the light-absorbing species within a solid sample. A spectroscopist needs data from a phase-reference material for standardizing phase measurements and for correcting the instrumental effects on the observed phase. Unfortunately, there is no universally accepted phase-reference material. The authors have studied the photoacoustic-signal phase and magnitude behavior for several potential phase-reference materials as a function of experimental parameters, such as beam modulation frequency, sample position in the photoacoustic cell, and cell purge gas. Theoretically, an ideal surface-absorbing material would have a photoacoustic phase that trails the phase of the excitation light by 90{degree}. They have found no material with this behavior, although some come close under a limited range of conditions. The three samples were separately sealed in the photoacoustic detector and illuminated by a red LED that was modulated at selected frequencies. The phases of the samples vary rapidly at very low frequencies because of the response of the cell microphone. Above that range, all three are within 10{degree} of the ideal 90{degree}, but each varies linearly with frequency with a different slope. The behaviors of these and other samples will be discussed in detail.
Date: June 1, 1999
Creator: Jones, R.; Bajic, S. & McClelland, J.
Partner: UNT Libraries Government Documents Department

A study of coal formation

Description: Coal is a solid, brittle, more or less distinctly stratified, combustible, carbonaceous rock. It is being rediscovered as a reliable energy source, which, historically provided the resource base for the industrialization of the United States economy. A firm understanding of growth in coal development is important to the national energy scene so that the implications of factors influencing coal growth upon the industry`s ability to realize national energy objectives may be determined. As a result, the future of coal development will be facilitated by compiling basic facts on coal reserves, production, and utilization. In view of this, a review and assessment of facts pertaining to the nature and origin of coal is presented. The various properties and uses of coal are then described, followed by a discussion of the process of coal formation.
Date: March 1, 1995
Creator: Jubert, K.; Stevens, G. & Masudi, H.
Partner: UNT Libraries Government Documents Department

The contribution of carbonaceous aerosols to climate change

Description: Contribution of aerosols to climate change results from two effects: clear-sky and cloudy-sky forcing. The clear-sky climate forcing by carbonaceous aerosols from biomass burning and fossil fuel burning depends on the relative contribution of scattering and absorption by the aerosols which in turn depends on the fraction of aerosol mass associated with black carbon and its size distribution. This paper reviews estimates for the emission of carbonaceous aerosols, placing these estimates in the context of estimates for the emissions of anthropogenic and natural sulfate aerosols and natural sources of organic particulate matter. The cloudy-sky forcing from carbonaceous aerosols is difficult to estimate because, among other factors, it depends on the amount of absorption by the aerosols in the cloud. It is also highly sensitive to the assumed pre-existing, natural aerosol abundance. An upper limit for this cloudy-sky forcing is -4.4 W/m{sup 2}, but may range as low as -2.4 W/m{sup 2}, depending on background aerosol concentrations. These estimates do not yet account for absorption of radiation by black carbon associated with cloud or the presence of pre-existing dust particles.
Date: April 1, 1996
Creator: Penner, J.E.; Chuang, C.C. & Liousse, C.
Partner: UNT Libraries Government Documents Department

Carbon nanotubes for hydrogen storage as being studied by the National Renewable Energy Laboratory. Technical evaluation report

Description: On June 17--18, the author met with Dr. Mike Heben of the National Renewable Energy Laboratory (NREL) to discuss his research on the development of carbon nanotubes to be used for the storage of hydrogen on-board a vehicle. Dr. Heben has been working for the past several years on a project that will develop single walled nanotubes (SWNTs) composed of carbon for storage of hydrogen. Dr. Heben has spent much time trying to develop a method by which he could produce SWNTs in sufficient quantity, and then demonstrate the adsorption and desorption of hydrogen from these nanotubes at room temperature. While Dr. Heben was able to show hydrogen adsorption levels of up to 10% on a SWNT basis, generation of SWNTs from an arc-discharge was only about 0.05% of the total soot formation. Therefore, increasing SWNT concentration was a key consideration. Findings from the meeting with Dr. Heben are presented.
Date: August 1, 1997
Creator: Skolnik, E.G.
Partner: UNT Libraries Government Documents Department

Irreversible gettering of thionyl chloride

Description: The authors have successfully demonstrated the irreversible gettering of SOCl{sub 2} by ZnO/ASZMTEDA carbon over a modest temperature range. While thionyl chloride decomposition was slow below {minus}20 C, lower temperatures are expected to be less of a problem than at higher temperatures. The approximately 30 cc of thionyl chloride in a typical D-cell would require 50 g of ZnO and 107 g of ASZMTEDA carbon. Fortunately, since it is unlikely to happen at all, it is common practice to assume only one cell will fail (leak) in a given battery pack. So, one charge of getter can protect the whole battery pack. In summary, ZnO/ASZMTEDA carbon fulfills all of the requirements of an ideal getter including: irreversible binding or reaction with SOCl{sub 2}, high volumetric uptake capacity, high efficiency, non-volatile, air stable, insensitive to poisoning, non-toxic, cheap, non-corrosive, and the gettering product is not a liquid or oil that could block further flow or accessibility. Future work in this area includes incorporation of the ZnO and carbon into a structural open-celled porous monolith, as well as, gettering for other types of batteries (e.g., Li/MnO{sub 2}).
Date: November 1, 1999
Creator: Whinnery, LeRoy; Goods, Steve; Buffleben, George & Sheppodd, Tim
Partner: UNT Libraries Government Documents Department

Carbonaceous materials as lithium intercalation anodes

Description: Commercial and polymer-derived carbonaceous materials were examined as lithium intercalation anodes in propylene carbonate (pyrolysis < 1350C, carbons) and ethylene carbonate/dimethyl carbonate (graphites) electrolytes. The reversible capacity (180--355 mAh/g) and the irreversible capacity loss (15--200 % based on reversible capacity) depend on the type of binder, carbon type, morphology, and phosphorus doping concentration. A carbon-based binder was chosen for electrode fabrication, producing mechanically and chemically stable electrodes and reproducible results. Several types of graphites had capacity approaching LiC{sub 6}. Petroleum fuel green cokes doped with phosphorous gave more than a 20 % increase in capacity compared to undoped samples. Electrochemical characteristics are related to SEM, TEM, XRD and BET measurements.
Date: October 1, 1994
Creator: Tran, T.D.; Feikert, J.H.; Mayer, S.T.; Song, X. & Kinoshita, K.
Partner: UNT Libraries Government Documents Department

A device for the determination of low concentrations of oxygen in carbonaceous materials

Description: Oxygen in carbonaceous materials is converted to carbon monoxide (CO) by pyrolyzing the material in a stream of oxygen-free helium. The CO is reacted with Ni{sup 63}, a radioactive isotope of nickel, to form nickel tetracarbanyl (Ni{sup 63}(CO){sub 4}) which is carried by the helium stream into a flow-through gas proportional counter. The quantity of Ni(CO){sub 4} is determined by the radioactivity of the gas as measured by the gas proportional counter. After exiting the flow through counter the Ni{sub 63}(CO){sub 4} is destroyed by exposing it to high temperatures. The Ni{sub 63} is retained within the apparatus while the CO is flushed from the system after being oxidized to carbon dioxide (CO{sub 2}). The detection limit is estimated to be less than 1 part per billion oxygen for a 10 mg sample.
Date: December 31, 1991
Creator: Schultz, H.
Partner: UNT Libraries Government Documents Department

Soft x-ray microanalysis and microscopy: A unique probe of the organic chemistry of heterogeneous solids

Description: STXM and C-NEXAFS (carbon near edge absorption micro-spectroscopy) microanalysis were used to analysis the microchemistry of cokes and highly carbonaceous materials. The issue of molecular orientation is addressed by using the intrinsic polarization of the x-ray beam at X1A beamline at NSLS.
Date: August 1, 1995
Creator: Cody, G.D.; Botto, R.E.; Ade, H.; Wirick, S.; Davis, A. & Mitchell, G.
Partner: UNT Libraries Government Documents Department

Small angle neutron scattering analysis of novel carbons for lithium secondary batteries.

Description: Small angle neutron scattering analyses of carbonaceous materials used as anodes in lithium ion cells have been performed. The carbons have been synthesized using pillared clays (PILCs) as inorganic templates. Pillared clays are layered silicates whose sheets have been permanently propped open by sets of thermally stable molecular props. The calcined PILC was loaded with five different organic precursors and heated at 700 C under nitrogen. When the inorganic pillars were removed by acid treatment, carbon sheets are produced with holes. The fitting of the data in the high q region suggested that the carbon sheets have voids with radii ranging from 4 to 8 {angstrom}. Similar radii were obtained for the PILC and PILC/organic precursor, which suggests that the carbon was well distributed in the clay prior to pyrolysis.
Date: January 14, 1998
Creator: Sandi, G.; Thiyagarajan, P.; Winans, R. & Carrado, K.
Partner: UNT Libraries Government Documents Department

A theoretical equation of state for detonation products

Description: A theoretical equation of state for detonation products is described that places particular emphasis on the characterization of small carbon clusters (20{angstrom}--50{angstrom} in diameter) in the products. Diamond clusters are modeled with the dangling bonds on the surface atoms (up to 30% of the cluster) capped by various radicals composed of C, H, N, and O from the background molecular fluid mixture. Free energy methods for the surface groups are used to determine the chemical equilibrium composition of the cluster surface as well as the surrounding molecular fluid mixture. The surface composition shows dramatic changes in composition over some regions and varies slowly in others. A perturbation theory approach is used for the mixture of molecular fluids that also includes features based on Monte Carlo simulations.
Date: December 31, 1998
Creator: Shaw, M.S.
Partner: UNT Libraries Government Documents Department

Novel carbonaceous materials used as anodes in lithium ion cells

Description: The objective of this work is to synthesize disordered carbons used as anodes in lithium ion batteries, where the porosity and surface area are controlled. Both parameters are critical since the irreversible capacity obtained in the first cycle seems to be associated with the surface area (an exfoliation mechanism occurs in which the exposed surface area continues to increase).
Date: September 1, 1997
Creator: Sandi, G.; Winans, R.E. & Carrado, K.A.
Partner: UNT Libraries Government Documents Department

Tribological performance of NFC coatings under oil lubrication[Near Frictionless Carbon]

Description: An increase in engine and vehicle efficiency usually requires an increase in the severity of contact at the interfaces of many critical components. Examples of such components include piston rings and cylinder liners in the engine, gears in the transmission and axle, bearings, etc. These components are oil-lubricated and require enhancement of their tribological performance. Argonne National Laboratory (ANL) recently developed a carbon-based coating with very low friction and wear properties. These near-frictionless-carbon (NFC) coatings have potential for application in various engine components for performance enhancement. This paper presents the study of the tribological performance of NFC-coated steel surfaces when lubricated with fully formulated and basestock synthetic oils. The NFC coatings reduced both the friction and wear of lubricated steel surfaces. The effect of the coating was much more pronounced in tests with basestock oil. This suggests that NFC-coated parts may not require heavily formulated lubricant oils to perform satisfactorily in terms of reliability and durability.
Date: January 20, 2000
Creator: Ajayi, O. O.; Alzoubi, M.; Erdemir, A.; Fenske, G. R.; Eryilmaz, O. L. & Zimmerman, S.
Partner: UNT Libraries Government Documents Department

Fundamental study of low-NOx combustion fly ash utilization. Semiannual report, May 1, 1998--October 31, 1998

Description: The objective of the current work was to investigate the oxidation reactivity of fly ash carbons, using thermogravimetric analysis techniques. Good measures of the oxidation reactivity of fly ash carbon were the critical temperature (T{sub cr}) and the late burnout temperature (T{sub late}). The lower the critical temperature of the fly ash carbon, the more reactive the sample. By contrast, the higher T{sub late}, the less reactive the fly ash carbon. The difference between T{sub cr} and T{sub late} provided information about the reactivity distribution and was mainly dependent on fly ash carbon content (Loss-On-Ignition (LOI)). Fly ash carbons having different origins, some from lower rank coals and some from higher rank coals had slightly different reactivities. Class C fly ash carbons from low rank coals were more reactive than the typical class F fly ash carbons from higher rank coals. The reactivity parameters did not, however, provide any additional ability to predict the suitability of a given ash for use in concrete.
Date: October 20, 1999
Creator: Hurt, R.H. & Suuberg, E.M.
Partner: UNT Libraries Government Documents Department

Tailored Porous Materials

Description: Tailoring of porous materials involves not only chemical synthetic techniques for tailoring microscopic properties such as pore size, pore shape, pore connectivity, and pore surface reactivity, but also materials processing techniques for tailoring the meso- and the macroscopic properties of bulk materials in the form of fibers, thin films and monoliths. These issues are addressed in the context of five specific classes of porous materials: oxide molecular sieves, porous coordination solids, porous carbons, sol-gel derived oxides, and porous heteropolyanion salts. Reviews of these specific areas are preceded by a presentation of background material and review of current theoretical approaches to adsorption phenomena. A concluding section outlines current research needs and opportunities.
Date: November 9, 1999
Creator: BARTON,THOMAS J.; BULL,LUCY M.; KLEMPERER,WALTER G.; LOY,DOUGLAS A.; MCENANEY,BRIAN; MISONO,MAKOTO et al.
Partner: UNT Libraries Government Documents Department

CONTRIBUTION OF SEMI-VOLATILE ORGANIC MATERIAL TO AMBIENT PM2.5

Description: Both annual 24-h average and seasonal diurnal samples collected at NETL during the research program have been analyzed. The fine particulate components determined include PM{sub 2.5} mass, ammonium sulfate, ammonium nitrate, elemental and organic carbonaceous material and trace elements. The analysis of the nitrate and organic material includes both the identification of nonvolatile material retained by the particle collection filter and semi-volatile material lost from the particles during sample collection. The results obtained in these analyses indicate that both the semivolatile and nonvolatile organic material in the fine particles sampled at the NETL site originate from mobile emissions in the local area. However, the majority of the nonvolatile material is associated with primary emissions and the majority of the semi-volatile material is secondary, being formed from photochemical processes in the atmosphere. In contrast, the fine particulate sulfate does not originate from the local area but is transported into the study region, mostly from sources in the Ohio River Valley. These observations have been supported by both detailed meteorological and apportionment analysis of the data.
Date: April 1, 2004
Creator: Eatough, Delbert J.; Modey, William K.; Sizemore, Rebecca & Simpson, Michael
Partner: UNT Libraries Government Documents Department

An Automatic Micromuffle for the Determination of Ash in Carbonaceous Material

Description: Abstract: An automatic micromuffle for the determination of the ash content of small samples of carbonaceous material is comprised of a furnace of the radiant-heating type with a direct reading pyrometer for temperature control. This furnace can be assembled with a minimum of labor using parts available from scientific laboratory apparatus companies.
Date: March 1954
Creator: Meyrowitz, Robert & Massoni, C. J.
Partner: UNT Libraries Government Documents Department