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Description: Evidence is presented which points to (at least) two bound forms of bacteriochlorophyll present in chromatophores of Rhodospirillum rubrum, both of them readily converted to unbound bacteriochlorophyll (abs. max. 770 mu) when the chromatophores are extracted with acetone or ethanol. Controlled oxidation of the chromatophores with Ir(IV) or with Zn(II) and ferricyanide preferentially destroys the more strongly absorbing pigment (abs. max. 880 mu) but brings about only a slight decrease in the magnitude of the photoinduced absorption changes at 810 and 792 mu. Such oxidations yield a new pigment, absorbing at 715 mu in the aqueous preparation and, more strongly, at 680-684 mu when the pigment is extracted into organic solvents. This pigment is formed irreversibly and is therefore different from the material formed by photooxidation of chromatophores. Its visible spectrum and the spectrum of the material formed from it by acidification suggest that it is a chlorophyll-like substance, possibly derived from bacteriochlorophyll by (two-electron) oxidation of one of the dihydropyrrole rings to a pyrrole ring. Directions are given for separation of this pigment from other colored compounds present in the oxidation mixtures.
Date: October 1, 1964
Creator: Gould, Edwin S.; Kuntz Jr., Irwin D. & Calvin, Melvin
Partner: UNT Libraries Government Documents Department

Degradation of Isotopic Lactate and Acetate

Description: A scheme of glucose degradation has been validated by the use of intermediates of known isotopic composition. In this scheme: glucose {yields} lactic acid {yields} CO{sub 2} (C-3,4) + acetic acid {yields} CO{sub 2} (C-2,5) + acetone {yields} iodoform (C-1,6) + acetate (C-1,6; 2,5), it was found that (a) in the oxidation of lactic acid, approximately 4.7% of the acetic acid was oxidized to CO{sub 2}; and (b) under the conditions prescribed, BaCO{sub 3} from the degradation of Ba acetate contained approximately 1.5% of the activity of the methyl group.
Date: February 24, 1948
Creator: Aronoff, S.; Haas, V.A. & Fries, B.A.
Partner: UNT Libraries Government Documents Department

Control of Electronic Conduction at an Oxide Heterointerface using Surface Polar Adsorbates

Description: We study the effect of the surface adsorption of a variety of common laboratory solvents on the conductivity at the interface between LaAlO{sub 3} and SrTiO{sub 3}. This interface possesses a range of intriguing physics, notably a proposed connection between the surface state of the LaAlO{sub 3} and the conductivity buried in the SrTiO{sub 3}. We show that the application of chemicals such as acetone, ethanol, and water can induce a large change (factor of three) in the conductivity. This phenomenon is observed only for polar solvents. These data provide experimental evidence for a general polarization-facilitated electronic transfer mechanism.
Date: August 19, 2011
Creator: Bell, Christopher
Partner: UNT Libraries Government Documents Department

Biogenic and biomass burning sources of acetone to the troposphere

Description: Acetone may be an important source of reactive odd hydrogen in the upper troposphere and lower stratosphere. This source of odd hydrogen may affect the concentration of a number of species, including ozone, nitrogen oxides, methane, and others. Traditional, acetone had been considered a by-product of the photochemical oxidation of other species, and had not entered models as a primary emission. However, recent work estimates a global source term of 40-60 Tg acetone/year. Of this, 25% is directly emitted during biomass burning, and 20% is directly emitted by evergreens and other plants. Only 3% is due to anthropogenic/industrial emissions. The bulk of the remainder, 51% of the acetone source, is a secondary product from the oxidation of propane, isobutane, and isobutene. Also, while it is speculated that the oxidation of pinene (a biogenic emission) may also contribute about 6 Tg/year, this term is highly uncertain. Thus, the two largest primary sources of acetone are biogenic emission and biomass burning, with industrial/anthropogenic emissions very small in comparison.
Date: April 1, 1997
Creator: Atherton, C. S.
Partner: UNT Libraries Government Documents Department

Rapid, automated gas chromatographic detection of organic compounds in ultra-pure water

Description: An automated gas chromatography was used to analyze water samples contaminated with trace (parts-per-billion) concentrations of organic analytes. A custom interface introduced the liquid sample to the chromatography. This was followed by rapid chromatographic analysis. Characteristics of the analysis include response times less than one minute and automated data processing. Analytes were chosen based on their known presence in the recycle water streams of semiconductor manufacturers and their potential to reduce process yield. These include acetone, isopropanol, butyl acetate, ethyl benzene, p-xylene, methyl ethyl ketone and 2-ethoxy ethyl acetate. Detection limits below 20 ppb were demonstrated for all analytes and quantitative analysis with limited speciation was shown for multianalyte mixtures. Results are discussed with respect to the potential for on-line liquid process monitoring by this method.
Date: February 15, 2000
Partner: UNT Libraries Government Documents Department

Stability of Tl-Ba-Ca-Cu-O Superconducting Thin Films

Description: We report the stability of TlBa{sub 2}CaCu{sub 2}O{sub 7} (Tl-1212) and Tl{sub 2}Ba{sub 2}CaCu{sub 2}O{sub 8} (T1-2212) thin films and by inference, the stability of TlBa{sub 2}Ca{sub 2}Cu{sub 3}O{sub 9} (Tl-1223) and Tl{sub 2}Ba{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} (Tl-2223) thin films, under a variety of conditions. In general, we observe that the stability behavior of the single Tl-O layer materials (Tl-1212 and Tl-1223)are similar and the double Tl-O layer materials (Tl-2212 and Tl-2223) are similar. All films are stable with repeated thermal cycling to cryogenic temperatures. Films are also stable in acetone and methanol. Moisture degrades film quality rapidly, especially in the form of vapor. Tl-1212 is more sensitive to vapor than Tl-2212. These materials are stable to high temperatures in either N{sub 2}, similar to vacuum for the cuprates, and O{sub 2} ambients. While total degradation of properties (superconducting and structural) occur at the same temperatures for all phases, 600 C in N{sub 2} and 700 C in O{sub 2}, the onset of degradation occurs at somewhat lower temperatures for Tl-1212 than for Tl-2212 films. In all cases, sample degradation is associated with Tl depletion from the films.
Date: August 23, 1999
Creator: Siegal, M.P.; Overmyer, D.L.; Venturini, E.L.; Padilla, R.R. & Provencio, P.N.
Partner: UNT Libraries Government Documents Department

Solvent Extraction of Chemical Attribution Signature Compounds from Painted Wall Board: Final Report

Description: This report summarizes work that developed a robust solvent extraction procedure for recovery of chemical attribution signature (CAS) compound dimethyl methyl phosphonate (DMMP) (as well as diethyl methyl phosphonate (DEMP), diethyl methyl phosphonothioate (DEMPT), and diisopropyl methyl phosphonate (DIMP)) from painted wall board (PWB), which was selected previously as the exposed media by the chemical attribution scientific working group (CASWG). An accelerated solvent extraction approach was examined to determine the most effective method of extraction from PWB. Three different solvent systems were examined, which varied in solvent strength and polarity (i.e., 1:1 dichloromethane : acetone,100% methanol, and 1% isopropanol in pentane) with a 1:1 methylene chloride : acetone mixture having the most robust and consistent extraction for four original target organophosphorus compounds. The optimum extraction solvent was determined based on the extraction efficiency of the target analytes from spiked painted wallboard as determined by gas chromatography x gas chromatography mass spectrometry (GCxGC-MS) analysis of the extract. An average extraction efficiency of approximately 60% was obtained for these four compounds. The extraction approach was further demonstrated by extracting and detecting the chemical impurities present in neat DMMP that was vapor-deposited onto painted wallboard tickets.
Date: October 29, 2009
Creator: Wahl, Jon H. & Colburn, Heather A.
Partner: UNT Libraries Government Documents Department

Indoor Secondary Pollutants from Household Product Emissions inthe Presence of Ozone: A Bench-Scale Chamber Study

Description: Ozone-driven chemistry is a major source of indoor secondary pollutants of health concern. This study investigates secondary air pollutants formed from reactions between constituents of household products and ozone. Gas-phase product emissions were introduced along with ozone at constant rates into a 198-L Teflon-lined reaction chamber. Gas-phase concentrations of reactive terpenoids and oxidation products were measured. Formaldehyde was a predominant oxidation byproduct for the three studied products, with yields under most conditions of 20-30% with respect to ozone consumed. Acetaldehyde, acetone, glycolaldehyde, formic acid and acetic acid were each also detected for two or three of the products. Immediately upon mixing of reactants, a scanning mobility particle sizer detected particle nucleation events that were followed by a significant degree of ultrafine particle growth. The production of secondary gaseous pollutants and particles depended primarily on the ozone level and was influenced by other parameters such as the air-exchange rate. Hydroxyl radical concentrations in the range 0.04-200 x 10{sup 5} molecules cm{sup -3} were measured. OH concentrations were observed to vary strongly with residual ozone level in the chamber, which was in the range 1-25 ppb, as is consistent with expectations from a simplified kinetic model. In a separate test, we exposed the dry residue of two products to ozone in the chamber and observed the formation of gas-phase and particle-phase secondary oxidation products.
Date: October 1, 2005
Creator: Destaillats, Hugo; Lunden, Melissa M.; Singer, Brett C.; Coleman,Beverly K.; Hodgson, Alfred T.; Weschler, Charles J. et al.
Partner: UNT Libraries Government Documents Department

Highly Selective Synthesis of Catalytically Active Monodisperse Rhodium Nanocubes

Description: Synthesis of monodisperse and shape-controlled colloidal inorganic nanocrystals (NCs) is of increasing scientific interest and technological significance. Recently, shape control of Pt, Pd, Ag, Au, and Rh NCs has been obtained by tuning growth kinetics in various solution-phase approaches, including modified polyol methods, seeded growth by polyol reduction, thermolysis of organometallics, and micelle techniques. Control of reduction kinetics of the noble metal precursors and regulation of the relative growth rates of low-index planes (i.e. {l_brace}100{r_brace} and {l_brace}111{r_brace}) via selective adsorption of selected chemical species are two keys for achieving shape modification of noble metal NCs. One application for noble metal NCs of well-defined shape is in understanding how NC faceting (determines which crystallographic planes are exposed) affects catalytic performance. Rh NCs are used in many catalytic reactions, including hydrogenation, hydroformylation, hydrocarbonylation, and combustion reactions. Shape manipulation of Rh NCs may be important in understanding how faceting on the nanoscale affects catalytic properties, but such control is challenging and there are fewer reports on the shape control of Rh NCs compared to other noble metals. Xia and coworkers obtained Rh multipods exhibiting interesting surface plasmonic properties by a polyol approach. The Somorjai and Tilley groups synthesized crystalline Rh multipods, cubes, horns and cuboctahedra, via polyol seeded growth. Son and colleagues prepared catalytically active monodisperse oleylamine-capped tetrahedral Rh NCs for the hydrogenation of arenes via an organometallic route. More recently, the Somorjai group synthesized sizetunable monodisperse Rh NCs using a one-step polyol technique. In this Communication, we report the highly selective synthesis of catalytically active, monodisperse Rh nanocubes of < 10 nm by a seedless polyol method. In this approach, Br{sup -} ions from trimethyl(tetradecyl)ammonium bromide (TTAB) effectively stabilize the {l_brace}100{r_brace} faces of Rh NCs, and induce the evolution of nanocubes (Scheme 1). For a typical synthesis, 0.2 mmol RhCl{sub 3} hydrate, ...
Date: February 21, 2009
Creator: Zhang, Y.; Grass, M.E.; Kuhn, J.N.; Tao, F.; Habas, S.E.; Huang, W. et al.
Partner: UNT Libraries Government Documents Department

Metagenomic insights into evolution of heavy metal-contaminated groundwater microbial community

Description: Understanding adaptation of biological communities to environmental change is a central issue in ecology and evolution. Metagenomic analysis of a stressed groundwater microbial community reveals that prolonged exposure to high concentrations of heavy metals, nitric acid and organic solvents ({approx}50 years) has resulted in a massive decrease in species and allelic diversity as well as a significant loss of metabolic diversity. Although the surviving microbial community possesses all metabolic pathways necessary for survival and growth in such an extreme environment, its structure is very simple, primarily composed of clonal denitrifying {gamma}- and {beta}-proteobacterial populations. The resulting community is overabundant in key genes conferring resistance to specific stresses including nitrate, heavy metals and acetone. Evolutionary analysis indicates that lateral gene transfer could have a key function in rapid response and adaptation to environmental contamination. The results presented in this study have important implications in understanding, assessing and predicting the impacts of human-induced activities on microbial communities ranging from human health to agriculture to environmental management, and their responses to environmental changes.
Date: July 1, 2010
Creator: Hemme, C.L.; Deng, Y.; Gentry, T.J.; Fields, M.W.; Wu, L.; Barua, S. et al.
Partner: UNT Libraries Government Documents Department

Life-cycle assessment of corn-based butanol as a potential transportation fuel.

Description: Butanol produced from bio-sources (such as corn) could have attractive properties as a transportation fuel. Production of butanol through a fermentation process called acetone-butanol-ethanol (ABE) has been the focus of increasing research and development efforts. Advances in ABE process development in recent years have led to drastic increases in ABE productivity and yields, making butanol production worthy of evaluation for use in motor vehicles. Consequently, chemical/fuel industries have announced their intention to produce butanol from bio-based materials. The purpose of this study is to estimate the potential life-cycle energy and emission effects associated with using bio-butanol as a transportation fuel. The study employs a well-to-wheels analysis tool--the Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET) model developed at Argonne National Laboratory--and the Aspen Plus{reg_sign} model developed by AspenTech. The study describes the butanol production from corn, including grain processing, fermentation, gas stripping, distillation, and adsorption for products separation. The Aspen{reg_sign} results that we obtained for the corn-to-butanol production process provide the basis for GREET modeling to estimate life-cycle energy use and greenhouse gas emissions. The GREET model was expanded to simulate the bio-butanol life cycle, from agricultural chemical production to butanol use in motor vehicles. We then compared the results for bio-butanol with those of conventional gasoline. We also analyzed the bio-acetone that is coproduced with bio-butanol as an alternative to petroleum-based acetone. Our study shows that, while the use of corn-based butanol achieves energy benefits and reduces greenhouse gas emissions, the results are affected by the methods used to treat the acetone that is co-produced in butanol plants.
Date: December 31, 2007
Creator: Wu, M.; Wang, M.; Liu, J.; Huo, H. & Systems, Energy
Partner: UNT Libraries Government Documents Department

Development and evaluation of on-line detection techniques for polar organics in ultrapure water

Description: An on-line monitor that can perform rapid, trace detection of polar organics such as acetone and isopropanol in ultrapure water (UPW) is necessary to efficiently recycle water in semiconductor manufacturing facilities. The detection of these analytes is problematic due to their high solubility in water, resulting in low partitioning into sensor coatings for direct water analysis or into the vapor phase for detection by vapor phase analyzers. After considering various options, we have evaluated two conventional laboratory techniques: gas chromatography and ion mobility spectroscopy. In addition, optimizations of sensor coating materials and sample preconditioning systems were performed with the goal of a low cost, chemical sensor system for this application. Results from these evaluations, including recommendations for meeting the needs of this application, are reported.
Date: March 1, 1996
Creator: Frye, G.C.; Blair, D.S.; Schneider, T.W.; Mowry, C.D.; Colburn, C.W. & Donovan, R.P.
Partner: UNT Libraries Government Documents Department

Photo-oxidation of organic compounds in liquid low-level mixed wastes at the INEL

Description: A bench-scale oxidation apparatus is implemented to study the effectiveness of using an artificial ultraviolet source, a 175-watt medium pressure mercury vapor lamp, to enhance the destruction of organic contaminants in water with chemical oxidants. The waste streams used in this study are samples or surrogates of mixed wastes at the Idaho National Engineering Laboratory. The contaminants that are investigated include methylene chloride, 1,1,1-trichlorethane, 1, 1-dichlororethane, acetone, 2-propanol, and ethylenediamine tetraacetic acid. We focus on H{sub 2}O{sub 2}-based oxidizers for our treatment scheme, which include the UV/H{sub 2}O{sub 2} system, the dark Fenton system (H{sub 2}O{sub 2}/Fe{sup 2+}), and the photo- assisted Fenton system (UV/H{sub 2}O{sub 2}/Fe{sup 3+}) is used in particular. Variables include concentration of the chemical oxidizer, concentration of the organic contaminant, and the elapsed reaction time. Results indicate that the photo-assisted Fenton system provides the best overall performance of the oxidizing systems listed above, where decreases in concentrations of methylene chloride, 1,1,1- trichloroethane, 1,1-dichlororethane, 2-propanol, and ethylenediamine tetraacetic acid were seen. However, UV-oxidation treatment provided no measurable benefit for a mixed waste containing acetone in the presence of 2-propanol.
Date: August 1, 1996
Creator: Gering, K.L. & Schwendiman, G.L.
Partner: UNT Libraries Government Documents Department

Adapting the Bruel and Kjaer Multi-gas Monitor Type 1302 to measure selected volatile organic chemicals (VOCs) in soil

Description: The Bruel and Kjaer Multi-gas Monitor Type 1302 can simultaneously measure up to five different volatile organic chemicals (VOCS) in a single air sample by using optical filters combined with a photo acoustic detection method. The monitor has previously been validated to measure VOCs in water, by purging aqueous samples into Tedlar{trademark} bags. The method used to measure VOCs in water has been adapted for use with soil. Soil samples are diluted with water and VOCs are purged with air from the resulting slurry into a Tedlar{trademark} bag. The contents of the Tedlar{trademark} bag are then analyzed with the multi-gas monitor. Data have been generated for the measurement of chloroform, trichloroethylene, tetrachloroethylene, carbon tetrachloride, and acetone. The method is linear for these VOCs from approximately 1 to at least 128 {mu}g/g of soil (ppM). There is no measurable cross interference of these VOCs with each other when more than one is present in a single soil sample. Contaminants other than those being measured may interfere with detection of these VOCS, so some prior site characterization is required. The method is easy to perform, rapid, reproducible, and sensitive enough for field screening applications.
Date: April 1, 1995
Creator: Palausky, M.A.; Waters, L.C.; Counts, R.W. & Jenkins, R.A.
Partner: UNT Libraries Government Documents Department


Description: Hydroxyacetone (HA) is mainly produced in the atmosphere from oxidation of hydrocarbons of the type, CH{sub 3}(R)C=CH{sub 2}. Tuazon and Atkinson (1990) reported HA yield of 41% from the OH-initiated oxidation of methacrolein in the presence of NO{sub x}. Since methacrolein is a major product of isoprene oxidation (Carter and Atkinson, 1996), isoprene, a key biogenic hydrocarbon, is therefore expected to be an important source for HA. Consequently, knowledge of ambient concentration of HA would provide information needed to examine the applicability of isoprene reaction mechanisms developed in laboratory and to assess the contribution of isoprene to photooxidant production. The commonly used GC-FID technique involving cryo-focusing is unsuitable for HA owing to HA's thermal instability. When subjected to a temperature of 100 C for only a few seconds, HA was found to disappear completely. Since HA is highly soluble in water (it's Henry's law constant being {approx}2 x 10{sup 4} M atm{sup -1} at 20 C, Zhou and Lee, unpublished data), we developed a wet chemical technique similar in principle to the one we reported earlier (Lee and Zhou, 1993), namely, based on derivatization following liquid scrubbing. To increase the sensitivity, we adopted a fluorescence detection scheme based on o-phthaldialdehyde (OPA) chemistry. The technique was deployed in the field during two measurement periods at a NARSTO site located on Long Island (LI), New York. We report the principle and the operation of this technique and the results obtained from these field studies.
Date: October 4, 1999
Creator: KLOTZ,P.J.
Partner: UNT Libraries Government Documents Department

Vapor space characterization of waste Tank 241-C-111 (in situ): Results from samples collected on 6/20/94

Description: This report describes inorganic and organic analyses results from in situ samples obtained from the headspace of the Hanford waste storage Tank 241-C-111 (referred to as Tank C-111). The results described here were obtained to support safety and toxicological evaluations. A summary of the results for inorganic and organic analytes is listed in Summary Table 1. Detailed descriptions of the results appear in the text. Quantitative results were obtained for the inorganic compounds ammonia (NH{sub 3}), nitrogen dioxide (NO{sub 2}), nitric oxide (NO), hydrogen cyanide (HCN), and water vapor (H{sub 2}O). Sampling for sulfur oxides was not requested. Organic compounds were quantitatively determined. Five organic tentatively identified compounds (TICs) were observed above the detection limit of (ca.) 10 ppbv, but standards for most of these were not available at the time of analysis, and the reported concentrations are semiquantitative estimates. In addition, the authors looked for the 40 standard TO-14 analytes and observed 39. None of these compounds were above the 2-ppbv calibrated instrumental detection limit. However, it is believed that the detection of dichlorodifluoromethane and methyl benzene are real at these low concentrations. The five organic analytes with the highest estimated concentrations are listed in Summary Table 1. The five analytes account for approximately 100% of the total organic components in Tank C-111.
Date: October 1, 1995
Creator: Ligotke, M.W.; Pool, K.H.; Lucke, R.B.; McVeety, B.D.; Clauss, T.W.; McCulloch, M. et al.
Partner: UNT Libraries Government Documents Department

Emissions of non-methane organic compounds from a grassland site

Description: A mixture of oxygenated hydrocarbons (OxHCs), isoprene, and monoterpenes was detected in the emissions from a grassland site in the Midwestern United States. A plot dominated by crown vetch (Coronilla varia) and bluegrass (Poa spp.), exhibited a constant decrease in emissions of total non-methane organic compounds (NMOCs) from 580 {mu}g m{sup -2} hr{sup -1} in June 1992 to 150 {mu}g m{sup - 2} hr{sup -1} in October 1992, except for a slight increase in August. Oxygenated hydrocarbons (methanol, acetaldehyde, and acetone) and terpenes (isoprene, limonene, myrcene, {alpha}-pinene, and {beta}- pinene) composed about 90% and 10% of the identified NMOC emissions, respectively. Isoprene represented about 10% of the terpene emissions. Total NMOC emission rates based on vegetative biomass averaged 2.3 {mu}g g{sup -1} hr{sup -1}, with 10% of the identified NMOCs attributed to monoterpenes and the remainder mainly OxHCs. Over the course of the investigation, the relationship between the monoterpene emission rate and the temperature for a single plot was logarithmic and similar to the one between compound vapor pressure and temperature. However, emission rates normalized to temperature decreased throughout the summer and fall, indicating that parameterizations of emission rates from herbaceous plants must include a factor to compensate for environmental conditions such as soil moisture and nutrient deposition, which affect plant phenology and the seasonal pattern of species dominance.
Date: March 1996
Creator: Fukui, Yoshiko & Doskey, P. V.
Partner: UNT Libraries Government Documents Department


Description: A simplified procedure is described for the preparation of crystalline bacteriochlorophyll from R. rubrum. The chemical dehydrogenation of bacteriochlorophyll with quinones is shown to give high yields of 2-desvinyl-2acetyl-chlorophyll a, whereas the photo-oxidation of bacteriochlorophyll results in a mixture of products of which 2-desvinyl-2acetyl-chlorophyll a is only a minor constituent. A number of interesting results have been observed spectrophotometrically during these oxidations under different reaction conditions. These observations are discussed and possible reaction mechanisms are outlined. The proton magnetic resonance spectrum of 2-desvinyl-2acetyl-chlorophyll a in deuteroacetone and the visible absorption spectra of this pigment and its magnesium-free derivative in acetone are reported. As expected, these spectra exhibit a marked resemblance to chlorophyll a and pheophytin a.
Date: June 1, 1966
Creator: Smith, John R. Lindsay & Calvin, Melvin
Partner: UNT Libraries Government Documents Department

Electronic Surface Structures of Coal and Mineral Particles

Description: Surface science studies related to tribocharging and charge separation studies were performed on electrostatic beneficiation of coal. In contrast to other cleaning methods, electrostatic beneficiation is a dry cleaning process requiring no water or subsequent drying. Despite these advantages, there is still uncertainty in implementing large scale commercial electrostatic beneficiation of coal. The electronic surface states of coal macerals and minerals are difficult to describe due to their chemical complexity and variability [1]. The efficiency in separation of mineral particles from organic macerals depends upon these surface states. Therefore, to further understand and determine a reason for the bipolar charging observed in coal separation, surface analysis studies using Ultra-violet Photoelectron Spectroscopy (UPS) and X-ray Photoelectron Spectroscopy (XPS) were performed on coal samples and several materials that are used or considered for use in tribocharging. Electrostatic charging is a surface phenomenon, so the electronic surface states of the particles, which are influenced by the environmental conditions, determine both polarity and magnitude of tribocharging. UPS was used to measure the work function of the materials as typically used in ambient air. XPS was used to determine the surface chemistry in the form of contamination and degree of oxidation under the same environmental conditions. Mineral bearing coals are those amenable to electrostatic beneficiation. Three types of coal, Illinois No. 6, Pittsburgh No. 8, and Kentucky No. 9 were investigated in this study. Pulverized coal powder was tribocharged against copper. Pyritic and other ashes forming minerals in coal powders should charge with a negative polarity from triboelectrification, and organic macerals should acquire positive charge, according to the relative differences in the surface work functions between the material being charged and the charging medium. Different types of minerals exhibit different magnitudes of negative charge and some may also charge positively against copper [2]. Only the ...
Date: April 1, 2001
Creator: Mazumder, M.K.; Lindquist, D.A.; Tennal, K.B.; Trigwell, Steve; Farmer, Steve; Nutsukpul, Albert et al.
Partner: UNT Libraries Government Documents Department