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Sample records for air oxidation process

  1. The study of leachate treatment by using three advanced oxidation process based wet air oxidation

    PubMed Central

    2013-01-01

    Wet air oxidation is regarded as appropriate options for wastewater treatment with average organic compounds. The general purpose of this research is to determine the efficiency of three wet air oxidation methods, wet oxidation with hydrogen peroxide and absorption with activated carbon in removing organic matter and nitrogenous compounds from Isfahan's urban leachate. A leachate sample with the volume of 1.5 liters entered into a steel reactor with the volume of three liters and was put under a 10-bar pressure, at temperatures of 100, 200, and 300° as well as three retention times of 30, 60, and 90 minutes. The sample was placed at 18 stages of leachate storage ponds in Isfahan Compost Plant with the volume of 20 liters, using three WPO, WAO methods and a combination of WAO/GAC for leachate pre-treatment. Thirty percent of pure oxygen and hydrogen peroxide were applied as oxidation agents. The COD removal efficiency in WAO method is 7.8-33.3%, in BOD is 14.7-50.6%, the maximum removal percentage (efficiency) for NH4-N is 53.3% and for NO3-N is 56.4-73.9%. The removal efficiency of COD and BOD5 is 4.6%-34 and 24%-50 respectively in WPO method. Adding GAC to the reactor, the removal efficiency of all parameters was improved. The maximum removal efficiency was increased 48% for COD, 31%-43.6 for BOD5 by a combinational method, and the ratio of BOD5/COD was also increased to 90%. In this paper, WAO and WPO process was used for Leachate pre-treatment and WAO/GAC combinational process was applied for improving the organic matter removal and leachate treatment; it was also determined that the recent process is much more efficient in removing resistant organic matter. PMID:23369258

  2. Uranium Metal to Oxide Conversion by Air Oxidation –Process Development

    SciTech Connect

    Duncan, A

    2001-12-31

    Published technical information for the process of metal-to-oxide conversion of uranium components has been reviewed and summarized for the purpose of supporting critical decisions for new processes and facilities for the Y-12 National Security Complex. The science of uranium oxidation under low, intermediate, and high temperature conditions is reviewed. A process and system concept is outlined and process parameters identified for uranium oxide production rates. Recommendations for additional investigations to support a conceptual design of a new facility are outlined.

  3. Influence of annealing atmospheres and synthetic air treatment on solution processed zinc oxide thin film transistors

    NASA Astrophysics Data System (ADS)

    Busch, C.; Schierning, G.; Theissmann, R.; Schmechel, R.

    2012-08-01

    Thin film transistors (TFTs) based on active layers of zinc oxide prepared from a solution process were fabricated under different annealing conditions. The influence of the annealing gas as well as the influence of a subsequent exposure to synthetic air to the device properties is considered. Annealing under N2 or H2 atmosphere leads to a strong negative threshold voltage shift. With respect to known defect states in ZnO, two different donor states are suggested to be responsible for the negative threshold voltage. A subsequent synthetic air treatment causes in general a positive threshold voltage shift. However, transistors annealed under H2 degrade very fast under synthetic air in contrast to transistors annealed under N2. In order to obtain more information about the density of states (DOS) distribution, a transistor model for thin film transistors in the hopping transport regime (Vissenberg model) was utilized. For positive threshold voltages, the DOS distribution is independent from the gas treatment and the threshold voltage within the experimental accuracy. This indicates a shift of the Fermi-level within an exponentially decaying DOS. The change in the charge carrier density is either due to shallow donors or due to a charge transfer with acceptors at the surface. In contrast, for negative threshold voltages, the DOS distribution parameter rises, indicating a flatter DOS distribution. We suggest that the difference is due to the change from accumulation mode to the depletion mode of the device.

  4. Treatment of biomass gasification wastewater using a combined wet air oxidation/activated sludge process

    SciTech Connect

    English, C.J.; Petty, S.E.; Sklarew, D.S.

    1983-02-01

    A lab-scale treatability study for using thermal and biological oxidation to treat a biomass gasification wastewater (BGW) having a chemical oxygen demand (COD) of 46,000 mg/l is described. Wet air oxidation (WA0) at 300/sup 0/C and 13.8 MPa (2000 psi) was used to initially treat the BGW and resulted in a COD reduction of 74%. This was followed by conventional activated sludge treatment using operating conditions typical of municipal sewage treatment plants. This resulted in an additional 95% COD removal. Overall COD reduction for the combined process was 99%. A detailed chemical analysis of the raw BGW and thermal and biological effluents was performed using gas chromatography/mass spectrometry (GC/MS). These results showed a 97% decrease in total extractable organics with WA0 and a 99.6% decrease for combined WA0 and activated sludge treatment. Components of the treated waters tended to be fewer in number and more highly oxidized. An experiment was conducted to determine the amount of COD reduction caused by volatilization during biological treatment. Unfortunately, this did not yield conclusive results. Treatment of BGW using WA0 followed by activated sludge appears to be very effective and investigations at a larger scale are recommended.

  5. Improved air stability of perovskite solar cells via solution-processed metal oxide transport layers.

    PubMed

    You, Jingbi; Meng, Lei; Song, Tze-Bin; Guo, Tzung-Fang; Yang, Yang Michael; Chang, Wei-Hsuan; Hong, Ziruo; Chen, Huajun; Zhou, Huanping; Chen, Qi; Liu, Yongsheng; De Marco, Nicholas; Yang, Yang

    2016-01-01

    Lead halide perovskite solar cells have recently attracted tremendous attention because of their excellent photovoltaic efficiencies. However, the poor stability of both the perovskite material and the charge transport layers has so far prevented the fabrication of devices that can withstand sustained operation under normal conditions. Here, we report a solution-processed lead halide perovskite solar cell that has p-type NiO(x) and n-type ZnO nanoparticles as hole and electron transport layers, respectively, and shows improved stability against water and oxygen degradation when compared with devices with organic charge transport layers. Our cells have a p-i-n structure (glass/indium tin oxide/NiO(x)/perovskite/ZnO/Al), in which the ZnO layer isolates the perovskite and Al layers, thus preventing degradation. After 60 days storage in air at room temperature, our all-metal-oxide devices retain about 90% of their original efficiency, unlike control devices made with organic transport layers, which undergo a complete degradation after just 5 days. The initial power conversion efficiency of our devices is 14.6 ± 1.5%, with an uncertified maximum value of 16.1%.

  6. Improved air stability of perovskite solar cells via solution-processed metal oxide transport layers

    NASA Astrophysics Data System (ADS)

    You, Jingbi; Meng, Lei; Song, Tze-Bin; Guo, Tzung-Fang; Yang, Yang (Michael); Chang, Wei-Hsuan; Hong, Ziruo; Chen, Huajun; Zhou, Huanping; Chen, Qi; Liu, Yongsheng; De Marco, Nicholas; Yang, Yang

    2016-01-01

    Lead halide perovskite solar cells have recently attracted tremendous attention because of their excellent photovoltaic efficiencies. However, the poor stability of both the perovskite material and the charge transport layers has so far prevented the fabrication of devices that can withstand sustained operation under normal conditions. Here, we report a solution-processed lead halide perovskite solar cell that has p-type NiOx and n-type ZnO nanoparticles as hole and electron transport layers, respectively, and shows improved stability against water and oxygen degradation when compared with devices with organic charge transport layers. Our cells have a p-i-n structure (glass/indium tin oxide/NiOx/perovskite/ZnO/Al), in which the ZnO layer isolates the perovskite and Al layers, thus preventing degradation. After 60 days storage in air at room temperature, our all-metal-oxide devices retain about 90% of their original efficiency, unlike control devices made with organic transport layers, which undergo a complete degradation after just 5 days. The initial power conversion efficiency of our devices is 14.6 ± 1.5%, with an uncertified maximum value of 16.1%.

  7. Fast oxidation processes from emission to ambient air introduction of aerosol emitted by residential log wood stoves

    NASA Astrophysics Data System (ADS)

    Nalin, Federica; Golly, Benjamin; Besombes, Jean-Luc; Pelletier, Charles; Aujay-Plouzeau, Robin; Verlhac, Stéphane; Dermigny, Adrien; Fievet, Amandine; Karoski, Nicolas; Dubois, Pascal; Collet, Serge; Favez, Olivier; Albinet, Alexandre

    2016-10-01

    Little is known about the impact of post-combustion processes, condensation and dilution, on the aerosol concentration and chemical composition from residential wood combustion. The evolution of aerosol emitted by two different residential log wood stoves (old and modern technologies) from emission until it is introduced into ambient air was studied under controlled "real" conditions. The first objective of this research was to evaluate the emission factors (EF) of polycyclic aromatic hydrocarbons (PAH) and their nitrated and oxygenated derivatives from wood combustion. These toxic substances are poorly documented in the literature. A second objective was to evaluate the oxidation state of the wood combustion effluent by studying these primary/secondary compounds. EFs of Σ37PAHs and Σ27Oxy-PAHs were in the same range and similar to those reported in literature (4-240 mg kg-1). Σ31Nitro-PAH EFs were 2-4 orders of magnitude lower (3.10-2-8.10-2 mg kg-1) due to the low temperature and low emission of NO2 from wood combustion processes. An increase of equivalent EF of PAH derivatives was observed suggesting that the oxidation state of the wood combustion effluent from the emission point until its introduction in ambient air changed in a few seconds. These results were confirmed by the study of both, typical compounds of SOA formation from PAH oxidation and, PAH ratio-ratio plots commonly used for source evaluation.

  8. New kinetic insight into the spontaneous oxidation process of lithium in air by EPMA

    NASA Astrophysics Data System (ADS)

    Otero, Manuel; Lener, German; Trincavelli, Jorge; Barraco, Daniel; Nazzarro, Marcelo Sandro; Furlong, Octavio; Leiva, Ezequiel Pedro Marcos

    2016-10-01

    The exposure of metallic lithium to ambient air produces a fast corrosion reaction of the surface that continues to the bulk of the material. This spontaneous process was explored by means of X-ray Photoelectron Spectroscopy (XPS) and Electron Probe Micro-Analysis (EPMA). The combination of these techniques and Monte Carlo simulations allowed observing the formation of a film of lithium hydroxide (LiOH) and studying the growth within the material during the first 300 s. The corrosion is mainly due to the reaction of lithium with water and the diffusion of water through the growing LiOH film is the rate determining step. On the basis of a kinetic analysis we studied the mechanism of reaction and inferred a diffusion coefficient of D = (5.1 ± 0.4) × 10-12 cm2/s in agreement with results from the literature obtained using different techniques.

  9. Catalytic process for formaldehyde oxidation

    NASA Technical Reports Server (NTRS)

    Kielin, Erik J. (Inventor); Brown, Kenneth G. (Inventor); D'Ambrosia, Christine M. (Inventor)

    1996-01-01

    Disclosed is a process for oxidizing formaldehyde to carbon dioxide and water without the addition of energy. A mixture of formaldehyde and an oxidizing agent (e.g., ambient air containing formaldehyde) is exposed to a catalyst which includes a noble metal dispersed on a metal oxide which possesses more than one oxidation state. Especially good results are obtained when the noble metal is platinum, and the metal oxide which possesses more than one oxidation state is tin oxide. A promoter (i.e., a small amount of an oxide of a transition series metal) may be used in association with the tin oxide to provide very beneficial results.

  10. Wafer scale integration of reduced graphene oxide by novel laser processing at room temperature in air

    NASA Astrophysics Data System (ADS)

    Bhaumik, Anagh; Narayan, Jagdish

    2016-09-01

    Physical properties of reduced graphene oxide (rGO) strongly depend on the ratio of sp2 to sp3 hybridized carbon atoms, the presence of different functional groups, and the characteristics of the substrates. This research for the very first time illustrates successful wafer scale integration of 2D rGO with Cu/TiN/Si, employing pulsed laser deposition followed by laser annealing of carbon-doped copper layers using nanosecond excimer lasers. The XRD, SEM, and Raman spectroscopy measurements indicate the presence of large area rGO onto Si having Raman active vibrational modes: D, G, and 2D. A high resolution SEM depicts the morphology and formation of rGO from zone-refined carbon formed after nanosecond laser annealing. Temperature-dependent resistance data of rGO thin films follow the Efros-Shklovskii variable range hopping (VRH) model in the low-temperature region and Arrhenius conduction in the high-temperature regime. The photoluminescence spectra also reveal a less intense and broader blue fluorescence spectra, indicating the presence of miniature sized sp2 domains in the near vicinity of π* electronic states which favor the VRH transport phenomena. This wafer scale integration of rGO with Si employing a laser annealing technique will be useful for multifunctional integrated electronic devices and will open a new frontier for further extensive research in these functionalized 2D materials.

  11. Wet air oxidation of resorcinol as a model treatment for refractory organics in wastewaters from the wood processing industry.

    PubMed

    Weber, Bernd; Chavez, Alma; Morales-Mejia, Julio; Eichenauer, Sabrina; Stadlbauer, Ernst A; Almanza, Rafael

    2015-09-15

    Wastewater treatment systems are important tools to enhance sustainability in terms of reducing environmental impact and complying with sanitary requirements. This work addresses the wet air oxidation (WAO) process for pre-treatment of phenolic wastewater effluents. The aim was to increase biodegradability prior to a subsequent anaerobic stage. In WAO laboratory experiments using a micro-autoclave, the model compound resorcinol was degraded under different oxygen availability regims within the temperature range 150 °C-270 °C. The activation energy was determined to be 51.5 kJ/mol. Analysis of the products revealed that after 3 h of reaction at 230 °C, 97.5% degradation of resorcinol was achieved. At 250 °C and the same reaction time complete removal of resorcinol was observed. In this case the total organic carbon content was reduced down to 29%, from 118.0 mg/L down to 34.4 mg/L. Under these process conditions, the pollutant was only partially mineralized and the ratio of the biological oxygen demand relative to the chemical oxygen demand, which is 0.07 for resorcinol, was increased to a value exceeding 0.5. The main by-product acetic acid, which is a preferred compound for methanogenic bacteria, was found to account for 33% of the total organic carbon.

  12. Influences of Different Components on Agglomeration Behavior of MoS2 During Oxidation Roasting Process in Air

    NASA Astrophysics Data System (ADS)

    Wang, Lu; Zhang, Guo-Hua; Wang, Jing-Song; Chou, Kuo-Chih

    2016-08-01

    An agglomeration of the furnace charge always takes place during the oxidation roasting process of molybdenite concentrate (with the main component of MoS2) in multiple hearth furnaces, which greatly affects the production process and furnace service life. In the present work, a preliminary study about the influence of various components on the agglomeration phenomenon of pure MoS2 have been carried out. The results show that reaction temperature, impurity content, and air flow rate have significant effects on the agglomeration extent. Meanwhile, the impurity type added into the pure MoS2 plays a crucial role. It was found that CaO and MgO have a stronger sulfur-fixing effect and that the desulphurization of the roasted product was uncompleted. It was also concluded that the agglomeration is due to the formation of low-melting-point eutectics, including that between MoO3 and impurities and that between MoO3 and Mo4O11. It is suggested that decreasing the impurities contents, especially K, Cu, Pb, and Fe, is an effective method for reducing the extent of agglomeration.

  13. Process air quality data

    NASA Technical Reports Server (NTRS)

    Butler, C. M.; Hogge, J. E.

    1978-01-01

    Air quality sampling was conducted. Data for air quality parameters, recorded on written forms, punched cards or magnetic tape, are available for 1972 through 1975. Computer software was developed to (1) calculate several daily statistical measures of location, (2) plot time histories of data or the calculated daily statistics, (3) calculate simple correlation coefficients, and (4) plot scatter diagrams. Computer software was developed for processing air quality data to include time series analysis and goodness of fit tests. Computer software was developed to (1) calculate a larger number of daily statistical measures of location, and a number of daily monthly and yearly measures of location, dispersion, skewness and kurtosis, (2) decompose the extended time series model and (3) perform some goodness of fit tests. The computer program is described, documented and illustrated by examples. Recommendations are made for continuation of the development of research on processing air quality data.

  14. Tailoring indium oxide nanocrystal synthesis conditions for air-stable high-performance solution-processed thin-film transistors.

    PubMed

    Swisher, Sarah L; Volkman, Steven K; Subramanian, Vivek

    2015-05-20

    Semiconducting metal oxides (ZnO, SnO2, In2O3, and combinations thereof) are a uniquely interesting family of materials because of their high carrier mobilities in the amorphous and generally disordered states, and solution-processed routes to these materials are of particular interest to the printed electronics community. Colloidal nanocrystal routes to these materials are particularly interesting, because nanocrystals may be formulated with tunable surface properties into stable inks, and printed to form devices in an additive manner. We report our investigation of an In2O3 nanocrystal synthesis for high-performance solution-deposited semiconductor layers for thin-film transistors (TFTs). We studied the effects of various synthesis parameters on the nanocrystals themselves, and how those changes ultimately impacted the performance of TFTs. Using a sintered film of solution-deposited In2O3 nanocrystals as the TFT channel material, we fabricated devices that exhibit field effect mobility of 10 cm(2)/(V s) and an on/off current ratio greater than 1 × 10(6). These results outperform previous air-stable nanocrystal TFTs, and demonstrate the suitability of colloidal nanocrystal inks for high-performance printed electronics.

  15. Tailoring indium oxide nanocrystal synthesis conditions for air-stable high-performance solution-processed thin-film transistors.

    PubMed

    Swisher, Sarah L; Volkman, Steven K; Subramanian, Vivek

    2015-05-20

    Semiconducting metal oxides (ZnO, SnO2, In2O3, and combinations thereof) are a uniquely interesting family of materials because of their high carrier mobilities in the amorphous and generally disordered states, and solution-processed routes to these materials are of particular interest to the printed electronics community. Colloidal nanocrystal routes to these materials are particularly interesting, because nanocrystals may be formulated with tunable surface properties into stable inks, and printed to form devices in an additive manner. We report our investigation of an In2O3 nanocrystal synthesis for high-performance solution-deposited semiconductor layers for thin-film transistors (TFTs). We studied the effects of various synthesis parameters on the nanocrystals themselves, and how those changes ultimately impacted the performance of TFTs. Using a sintered film of solution-deposited In2O3 nanocrystals as the TFT channel material, we fabricated devices that exhibit field effect mobility of 10 cm(2)/(V s) and an on/off current ratio greater than 1 × 10(6). These results outperform previous air-stable nanocrystal TFTs, and demonstrate the suitability of colloidal nanocrystal inks for high-performance printed electronics. PMID:25915094

  16. Specific features of aluminum nanoparticle water and wet air oxidation

    SciTech Connect

    Lozhkomoev, Aleksandr S. Glazkova, Elena A. Svarovskaya, Natalia V. Bakina, Olga V. Kazantsev, Sergey O. Lerner, Marat I.

    2015-10-27

    The oxidation processes of the electrically exploded aluminum nanopowders in water and in wet air are examined in the paper. The morphology of the intermediate reaction products of aluminum oxidation has been studied using the transmission electron microscopy. It was shown that the aluminum nanopowder water oxidation causes the formation of the hollow spheres with mesoporous boehmite nanosheets coating. The wedge-like bayerite particles are formed during aluminum nanopowder wet air oxidation.

  17. Specific features of aluminum nanoparticle water and wet air oxidation

    NASA Astrophysics Data System (ADS)

    Lozhkomoev, Aleksandr S.; Glazkova, Elena A.; Svarovskaya, Natalia V.; Bakina, Olga V.; Kazantsev, Sergey O.; Lerner, Marat I.

    2015-10-01

    The oxidation processes of the electrically exploded aluminum nanopowders in water and in wet air are examined in the paper. The morphology of the intermediate reaction products of aluminum oxidation has been studied using the transmission electron microscopy. It was shown that the aluminum nanopowder water oxidation causes the formation of the hollow spheres with mesoporous boehmite nanosheets coating. The wedge-like bayerite particles are formed during aluminum nanopowder wet air oxidation.

  18. Wet-air oxidation cleans up black wastewater

    SciTech Connect

    Not Available

    1993-09-01

    Sterling Organics produces the analgesic paracetamol (acetaminophen) at its Dudley, England, plant. The wastewater from the batch process contains intermediates such as para-aminophenol (PAP) and byproducts such as thiosulfates, sulfites and sulfides. To stay ahead of increasingly strict environmental legislation, Sterling Organics installed a wet-air oxidation system at the Dudley facility in August 1992. The system is made by Zimpro Environmental Inc. (Rothschild, Wis.). Zimpro's wet-air oxidation system finds a way around the limitations of purely chemical or physical processes. In the process, compressed air at elevated temperature and pressure oxidizes the process intermediates and byproducts and removes the color from the wastewater.

  19. Application of sludge-based carbonaceous materials in a hybrid water treatment process based on adsorption and catalytic wet air oxidation.

    PubMed

    Julcour Lebigue, Carine; Andriantsiferana, Caroline; N'Guessan Krou; Ayral, Catherine; Mohamed, Elham; Wilhelm, Anne-Marie; Delmas, Henri; Le Coq, Laurence; Gerente, Claire; Smith, Karl M; Pullket, Suangusa; Fowler, Geoffrey D; Graham, Nigel J D

    2010-12-01

    This paper describes a preliminary evaluation of the performance of carbonaceous materials prepared from sewage sludges (SBCMs) in a hybrid water treatment process based on adsorption and catalytic wet air oxidation; phenol was used as the model pollutant. Three different sewage sludges were treated by either carbonisation or steam activation, and the physico-chemical properties of the resultant carbonaceous materials (e.g. hardness, BET surface area, ash and elemental content, surface chemistry) were evaluated and compared with a commercial reference activated carbon (PICA F22). The adsorption capacity for phenol of the SBCMs was greater than suggested by their BET surface area, but less than F22; a steam activated, dewatered raw sludge (SA_DRAW) had the greatest adsorption capacity of the SBCMs in the investigated range of concentrations (<0.05 mol L(-1)). In batch oxidation tests, the SBCMs demonstrated catalytic behaviour arising from their substrate adsorptivity and metal content. Recycling of SA_DRAW in successive oxidations led to significant structural attrition and a hardened SA_DRAW was evaluated, but found to be unsatisfactory during the oxidation step. In a combined adsorption-oxidation sequence, both the PICA carbon and a selected SBCM showed deterioration in phenol adsorption after oxidative regeneration, but a steady state performance was reached after 2 or 3 cycles.

  20. Assessment of the impact of oxidation processes on indoor air pollution using the new time-resolved INCA-Indoor model

    NASA Astrophysics Data System (ADS)

    Mendez, Maxence; Blond, Nadège; Blondeau, Patrice; Schoemaecker, Coralie; Hauglustaine, Didier A.

    2015-12-01

    INCA-Indoor, a new indoor air quality (IAQ) model, has been developed to simulate the concentrations of volatile organic compounds (VOC) and oxidants considering indoor air specific processes such as: emission, ventilation, surface interactions (sorption, deposition, uptake). Based on the detailed version of SAPRC-07 chemical mechanism, INCA-Indoor is able to analyze the contribution of the production and loss pathways of key chemical species (VOCs, oxidants, radical species). The potential of this model has been tested through three complementary analyses: a comparison with the most detailed IAQ model found in the literature, focusing on oxidant species; realistic scenarios covering a large range of conditions, involving variable OH sources like HONO; and the investigation of alkenes ozonolysis under a large range of indoor conditions that can increase OH and HO2 concentrations. Simulations have been run changing nitrous acid (HONO) concentrations, NOx levels, photolysis rates and ventilation rates, showing that HONO can be the main source of indoor OH. Cleaning events using products containing D-limonene have been simulated at different periods of the day. These scenarios show that HOX concentrations can significantly increase in specific conditions. An assessment of the impact of indoor chemistry on the potential formation of secondary species such as formaldehyde (HCHO) and acetaldehyde (CH3CHO) has been carried out under various room configuration scenarios and a study of the HOx budget for different realistic scenarios has been performed. It has been shown that, under the simulation conditions, formaldehyde can be affected by oxidant concentrations via chemical production which can account for more than 10% of the total production, representing 6.5 ppb/h. On the other hand, acetaldehyde production is affected more by oxidation processes. When the photolysis rates are high, chemical processes are responsible for about 50% of the total production of

  1. Oxidative Stress and Air Pollution Exposure

    PubMed Central

    Lodovici, Maura; Bigagli, Elisabetta

    2011-01-01

    Air pollution is associated with increased cardiovascular and pulmonary morbidity and mortality. The mechanisms of air pollution-induced health effects involve oxidative stress and inflammation. As a matter of fact, particulate matter (PM), especially fine (PM2.5, PM < 2.5 μm) and ultrafine (PM0.1, PM < 0.1 μm) particles, ozone, nitrogen oxides, and transition metals, are potent oxidants or able to generate reactive oxygen species (ROS). Oxidative stress can trigger redox-sensitive pathways that lead to different biological processes such as inflammation and cell death. However, it does appear that the susceptibility of target organ to oxidative injury also depends upon its ability to upregulate protective scavenging systems. As vehicular traffic is known to importantly contribute to PM exposure, its intensity and quality must be strongly relevant determinants of the qualitative characteristics of PM spread in the atmosphere. Change in the composition of this PM is likely to modify its health impact. PMID:21860622

  2. NEPTUNIUM OXIDE PROCESSING

    SciTech Connect

    Jordan, J; Watkins, R; Hensel, S

    2009-05-27

    The Savannah River Site's HB-Line Facility completed a campaign in which fifty nine cans of neptunium oxide were produced and shipped to the Idaho National Laboratory in the 9975 shipping container. The neptunium campaign was divided into two parts: Part 1 which consisted of oxide made from H-Canyon neptunium solution which did not require any processing prior to conversion into an oxide, and Part 2 which consisted of oxide made from additional H-Canyon neptunium solutions which required processing to purify the solution prior to conversion into an oxide. The neptunium was received as a nitrate solution and converted to oxide through ion-exchange column extraction, precipitation, and calcination. Numerous processing challenges were encountered in order make a final neptunium oxide product that could be shipped in a 9975 shipping container. Among the challenges overcome was the issue of scale: translating lab scale production into full facility production. The balance between processing efficiency and product quality assurance was addressed during this campaign. Lessons learned from these challenges are applicable to other processing projects.

  3. ADVANCED OXIDATION PROCESS

    SciTech Connect

    Dr. Colin P. Horwitz; Dr. Terrence J. Collins

    2003-11-04

    The removal of recalcitrant sulfur species, dibenzothiophene and its derivatives, from automotive fuels is an integral component in the development of cleaner burning and more efficient automobile engines. Oxidative desulfurization (ODS) wherein the dibenzothiophene derivative is converted to its corresponding sulfoxide and sulfone is an attractive approach to sulfur removal because the oxidized species are easily extracted or precipitated and filtered from the hydrocarbon phase. Fe-TAML{reg_sign} activators of hydrogen peroxide (TAML is Tetra-Amido-Macrocyclic-Ligand) catalytically convert dibenzothiophene and its derivatives rapidly and effectively at moderate temperatures (50-60 C) and ambient pressure to the corresponding sulfoxides and sulfones. The oxidation process can be performed in both aqueous systems containing alcohols such as methanol, ethanol, or t-butanol, and in a two-phase hydrocarbon/aqueous system containing tert-butanol or acetonitrile. In the biphasic system, essentially complete conversion of the DBT to its oxidized products can be achieved using slightly longer reaction times than in homogeneous solution. Among the key features of the technology are the mild reaction conditions, the very high selectivity where no over oxidation of the sulfur compounds occurs, the near stoichiometric use of hydrogen peroxide, the apparent lack of degradation of sensitive fuel components, and the ease of separation of oxidized products.

  4. Thermal and sonochemical synthesis of porous (Ce,Zr)O2 mixed oxides from metal β-diketonate precursors and their catalytic activity in wet air oxidation process of formic acid.

    PubMed

    Cau, Camille; Guari, Yannick; Chave, Tony; Larionova, Joulia; Nikitenko, Sergey I

    2014-07-01

    Porous (Ce0.5Zr0.5)O2 solid solutions were prepared by thermolysis (T=285 °C) or sonolysis (20 kHz, I=32 W cm(-2), Pac=0.46 W mL(-1), T=200 °C) of Ce(III) and Zr(IV) acetylacetonates in oleylamine or hexadecylamine under argon followed by heat treatment of the precipitates obtained in air at 450 °C. Transmission Electron Microscopy images of the samples show nanoparticles of ca. 4-6 nm for the two synthetic approaches. The powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray and μ-Raman spectroscopy of solids obtained after heat treatment indicate the formation of (Ce0.5Zr0.5)O2 solid solutions with a metastable tetragonal crystal structure for the two synthetic routes. The specific surface area of the samples varies between 78 and 149 m(2) g(-1) depending on synthesis conditions. The use of Barrett-Joyner-Halenda and t-plot methods reveal the formation of mixed oxides with a hybrid morphology that combines mesoporosity and microporosity regardless of the method of preparation. Platinum nanoparticles were deposited on the surface of the mixed oxides by sonochemical reduction of Pt(IV). It was found that the materials prepared by sonochemistry exhibit better resistance to dissolution during the deposition process of platinum. X-ray photoelectron spectroscopy analysis shows the presence of Pt(0) and Pt(II) on the surface of mixed oxides. Porous (Ce0.5Zr0.5)O2 mixed oxides loaded with 1.5%wt. platinum exhibit high activity in catalytic wet air oxidation of formic acid at 40 °C.

  5. Wet air oxidation of propellant wastewaters

    SciTech Connect

    Randall, T.L.; Copa, W.M.; Deitrich, M.J.

    1985-01-01

    Wet Air Oxidation studies have been conducted on a number of propellant wastewaters, to assess destruction levels of specific propellant components. OTTO fuel, used as a torpedo propellant, and hydrazine based rocket fuels were propellants of interest. OTTO fuel wastewaters contain substantial amounts of propylene glycol dinitrate. Hydrazine based rocket fuel wastewaters contain hydrazine and unsymmetrical dimethyl hydrazine. Laboratory Wet Air Oxidation studies on OTTO fuel wastewaters indicated that a 99+ percent destruction of propylene glycol dinitrate can be achieved at an oxidation temperature of 280/sup 0/C.

  6. Sulfide-oxidizing bacteria: Their role during air-stripping

    SciTech Connect

    Dell`Orco, M.J.; Chadik, P.A.; Bitton, G.; Neumann, R.P.

    1998-10-01

    Air-stripping, used to remove hydrogen sulfide naturally present in many groundwater supplies, commonly causes sulfide-oxidizing bacteria to proliferate. The role of sulfide-oxidizing bacteria during air-stripping was investigated in a diffused-air pilot reactor modeled after an existing treatment facility. Visible bacterial filaments and biofilm developed within a few days and increased both the sulfide removed from and turbidity in the effluent. Total sulfide, dissolved oxygen, pH, and electrode potential were monitored at eight locations in the reactor to characterize the process.

  7. Colour, lipid and protein stability of Rhea americana meat during air- and vacuum-packaged storage: influence of muscle on oxidative processes.

    PubMed

    Filgueras, R S; Gatellier, P; Aubry, L; Thomas, A; Bauchart, D; Durand, D; Zambiazi, R C; Santé-Lhoutellier, V

    2010-11-01

    Physicochemical characteristics and oxidative stability during storage were determined in Gastrocnemius pars interna (GN) and Iliofiburalis (IF) muscles of Rhea americana. Glycolytic potential (GP) and pH decline of muscles were measured within the first 24 h post mortem. Colour, lipid and protein stability were determined during storage of meat, i.e. 5 days under air-packaging at 4°C, or 28 days under vacuum-packaging at 4°C. In parallel, anti-oxidant status of muscles was estimated by measuring α-tocopherol content and anti-oxidant enzyme activities (superoxide dismutase and catalase), while pro-oxidant status was evaluated by determining haeminic iron and long chain fatty acids (especially polyunsaturated fatty acids). The ultimate pH was similar in both muscles, but the GP value was significantly higher in IF than in GN muscle. Haeminic iron and alpha-tocopherol content differed between muscles, with 30% more haeminic iron (p<0.05) and 134% more alpha-tocopherol (p<0.001) in IF than GN muscle. The IF muscle presented higher lipid content and lower PUFA/SFA ratio (polyunsaturated fatty acids/saturated fatty acids) than GN muscle. With storage under air-packaging, lipid and protein oxidation of rhea muscles increased up to 275% and 30%, respectively. This increase was more rapidly and marked in IF muscle. The IF also showed high level of metmyoglobin accumulation after 3 days of storage (47%) and was rejected by 1 consumer out of 2 in sensorial analysis. Under vacuum-packaging, both muscles showed a high stability of colour and no oxidation of lipids and proteins.

  8. HANDBOOK ON ADVANCED PHOTOCHEMICAL OXIDATION PROCESSES

    EPA Science Inventory

    This handbook summarizes commercial-scale system performance and cost data for advanced photochemical oxidation (APO) treatment of contaminated water, air, and solids. Similar information from pilot- and bench-scale evaluations of APO processes is also included to supplement the...

  9. HANDBOOK ON ADVANCED NONPHOTOCHEMICAL OXIDATION PROCESSES

    EPA Science Inventory

    The purpose of this handbook is to summarize commercial-scale system performance and cost data for advanced nonphotochemical oxidation (ANPO) treatment of contaminated water, air, and soil. Similar information from pilot-and bench-scale evaluations of ANPO processes is also inclu...

  10. Degradation process analysis of the azo dyes by catalytic wet air oxidation with catalyst CuO/γ-Al2O3.

    PubMed

    Hua, Li; Ma, Hongrui; Zhang, Lei

    2013-01-01

    Three azo dyes (Methyl Orange, Direct Brown and Direct Green) were treated by catalytic wet air oxidation (CWAO) with the catalysts CuO/γ-Al(2)O(3) prepared by consecutive impregnation. The relationship of decolorization extent, chemical oxygen demand (COD) removal extent and total organic carbon (TOC) in dye solution were investigated. The results indicated that the CuO/γ-Al(2)O(3) catalyst had excellent catalytic activity in treating azo dyes. Almost 99% of color and 70% of TOC were removed in 2h. The high removal extent of color and TOC indicated that the CWAO obtained perfect decomposition for pollutants. The degradation pathway of azo dyes was analyzed by UV-Vis, FTIR and MS. According to the examined results, the hydroxyl ((·)OH) radicals induced strong oxidizing effects in the target solution and destroyed the chromophoric groups of azo-benzene conjugated of the molecular structure. Considering characteristics of the dye structure, the azo bond (-N=N-) would first be attacked by the hydroxyl radical and other free radicals. With the continuous oxidization and the long reaction time at high temperature, these intermediates could be oxidized to the final oxidation products, such as water and carbon dioxide. PMID:22795071

  11. PROCESS OF OXIDIZING PLUTONIUM

    DOEpatents

    Coryell, C.D.

    1959-08-25

    The oxidation of plutonium to the plus six valence state is described. The oxidation is accomplished by treating the plutonium in aqueous solution with a solution above 0.01 molar in argentic ion, above 1.1 molar in nitric acid, and above 0.02 molar in argentous ion.

  12. Catalytic oxidative dehydrogenation process

    DOEpatents

    Schmidt, Lanny D.; Huff, Marylin

    2002-01-01

    A process for the production of a mono-olefin from a gaseous paraffinic hydrocarbon having at least two carbon atoms or mixtures thereof comprising reacting said hydrocarbons and molecular oxygen in the presence of a platinum catalyst. The catalyst consist essentially of platinum supported on alumina or zirconia monolith, preferably zirconia and more preferably in the absence of palladium, rhodium and gold.

  13. AIR QUALITY CRITERIA FOR OZONE AND RELATED PHOTOCHEMICAL OXIDANTS

    EPA Science Inventory

    The Clean Air Act requires periodic (5-year) update revision of criteria and National Ambient Air Quality Standards (NAAQS) for Ozone. The previous revision of the criteria contained in the Air Quality Criteria Document (AQCD) for Ozone and Related Photochemical Oxidants was co...

  14. Simulation of a hydraulic air ingestion process

    SciTech Connect

    Chen, F.C.; Golshani, A.

    1981-01-01

    A hydraulic air ingestion process which requires no mechanical moving parts to accomplish air compression but a downward flow of water and operates at nearly isothermal compression mode can be a viable alternative for the noncondensibles disposal of an OTEC open-cycle power system. A computer simulation of the process is presented based on one-dimensional lumped parameter analysis. Results of laboratory-scale experiments were obtained which compared favorably with the analytical results. A sensitivity study which depicts the effects of various parameters upon the applied head of the hydraulic air ingestion process is also presented.

  15. Oxide modified air electrode surface for high temperature electrochemical cells

    DOEpatents

    Singh, Prabhakar; Ruka, Roswell J.

    1992-01-01

    An electrochemical cell is made having a porous cermet electrode (16) and a porous lanthanum manganite electrode (14), with solid oxide electrolyte (15) between them, where the lanthanum manganite surface next to the electrolyte contains a thin discontinuous layer of high surface area cerium oxide and/or praseodymium oxide, preferably as discrete particles (30) in contact with the air electrode and electrolyte.

  16. USING WET AIR OXIDATION TECHNOLOGY TO DESTROY TETRAPHENYLBORATE

    SciTech Connect

    Adu-Wusu, K; Daniel McCabe, D; Bill Wilmarth, B

    2007-04-04

    A bench-scale feasibility study on the use of a Wet Air Oxidation (WAO) process to destroy a slurry laden with tetraphenylborate (TPB) compounds has been undertaken. WAO is an aqueous phase process in which soluble and/or insoluble waste constituents are oxidized using oxygen or oxygen in air at elevated temperatures and pressures ranging from 150 C and 1 MPa to 320 C and 22 MPa. The products of the reaction are CO{sub 2}, H{sub 2}O, and low molecular weight oxygenated organics (e.g. acetate, oxalate). Test results indicate WAO is a feasible process for destroying TPB, its primary daughter products [triphenylborane (3PB), diphenylborinic acid (2PB), and phenylboronic acid (1PB)], phenol, and most of the biphenyl byproduct. The required conditions are a temperature of 300 C, a reaction time of 3 hours, 1:1 feed slurry dilution with 2M NaOH solution, the addition of CuSO{sub 4}.5H{sub 2}O solution (500 mg/L Cu) as catalyst, and the addition of 2000 mL/L of antifoam. However, for the destruction of TPB, its daughter compounds (3PB, 2PB, and 1PB), and phenol without consideration for biphenyl destruction, less severe conditions (280 C and 1-hour reaction time with similar remaining above conditions) are adequate.

  17. Processing AIRS Scientific Data Through Level 3

    NASA Technical Reports Server (NTRS)

    Granger, Stephanie; Oliphant, Robert; Manning, Evan

    2010-01-01

    The Atmospheric Infra-Red Sounder (AIRS) Science Processing System (SPS) is a collection of computer programs, known as product generation executives (PGEs). The AIRS SPS PGEs are used for processing measurements received from the AIRS suite of infrared and microwave instruments orbiting the Earth onboard NASA's Aqua spacecraft. Early stages of the AIRS SPS development were described in a prior NASA Tech Briefs article: Initial Processing of Infrared Spectral Data (NPO-35243), Vol. 28, No. 11 (November 2004), page 39. In summary: Starting from Level 0 (representing raw AIRS data), the AIRS SPS PGEs and the data products they produce are identified by alphanumeric labels (1A, 1B, 2, and 3) representing successive stages or levels of processing. The previous NASA Tech Briefs article described processing through Level 2, the output of which comprises geo-located atmospheric data products such as temperature and humidity profiles among others. The AIRS Level 3 PGE samples selected information from the Level 2 standard products to produce a single global gridded product. One Level 3 product is generated for each day s collection of Level 2 data. In addition, daily Level 3 products are aggregated into two multiday products: an eight-day (half the orbital repeat cycle) product and monthly (calendar month) product.

  18. Exergy parametric study of carbon monoxide oxidation in moist air

    NASA Astrophysics Data System (ADS)

    Souidi, Ferhat; Benmalek, Toufik; Yesaad, Billel; Baik, Mouloud

    2015-12-01

    This study aims to analyze the oxidation of carbon monoxide in moist air from the second thermodynamic law aspect. A mathematical model of laminar premixed flame in a stagnation point flow has been achieved by numerical solution of the boundary layer equation using a self-made code. The chemical kinetic mechanism for flameless combustion of fuel, which is a mixture of carbon monoxide, oxygen, and water vapor, is modeled by 34 elementary reactions that incorporate (09) nine chemical species: CO, O, CO2, O2, H2O, H, H2, HO2, and OH. The salient point is that for all the parameters we considered, the exergy of the process is completely destroyed by irreversibilities. From the chemical viewpoint, the OH radical plays an essential role in CO oxidation. This latter point has already been mentioned by previous investigators.

  19. Catalytic wet air oxidation of high concentration pharmaceutical wastewater.

    PubMed

    Zhan, Wei; Wang, Xiaocong; Li, Daosheng; Ren, Yongzheng; Liu, Dongqi; Kang, Jianxiong

    2013-01-01

    In this study, we investigated the pretreatment of a high concentration pharmaceutical wastewater by catalytic wet air oxidation (CWAO) process. Different experiments were conducted to investigate the effects of the catalyst type, operating temperature, initial system pH, and oxygen partial pressure on the oxidation of the wastewater. Results show that the catalysts prepared by the co-precipitation method have better catalytic activity compared to others. Chemical oxygen demand (COD) conversion increased with the increase in temperature from 160 to 220 °C and decreased with the increase in pH. Moreover, the effect of the oxygen partial pressure on the COD conversion was significant only during the first 20 min of the reaction. Furthermore, the biodegradability of the wastewater improved greatly after CWAO, the ratio of BOD5/COD increased less than 0.1-0.75 when treated at 220 °C (BOD: biochemical oxygen demand). PMID:23676399

  20. Catalytic wet air oxidation of high concentration pharmaceutical wastewater.

    PubMed

    Zhan, Wei; Wang, Xiaocong; Li, Daosheng; Ren, Yongzheng; Liu, Dongqi; Kang, Jianxiong

    2013-01-01

    In this study, we investigated the pretreatment of a high concentration pharmaceutical wastewater by catalytic wet air oxidation (CWAO) process. Different experiments were conducted to investigate the effects of the catalyst type, operating temperature, initial system pH, and oxygen partial pressure on the oxidation of the wastewater. Results show that the catalysts prepared by the co-precipitation method have better catalytic activity compared to others. Chemical oxygen demand (COD) conversion increased with the increase in temperature from 160 to 220 °C and decreased with the increase in pH. Moreover, the effect of the oxygen partial pressure on the COD conversion was significant only during the first 20 min of the reaction. Furthermore, the biodegradability of the wastewater improved greatly after CWAO, the ratio of BOD5/COD increased less than 0.1-0.75 when treated at 220 °C (BOD: biochemical oxygen demand).

  1. Catalytic wet air oxidation for the treatment of emulsifying wastewater.

    PubMed

    Zhao, Jian-Fu; Chen, Ling; Lu, Yi-Cheng; Tang, Wen-Wei

    2005-01-01

    The wet air oxidation (WAO) and catalytic WAO (CWAO) of the high strength emulsifying wastewater containing nonionic surfactants have been investigated in terms of COD and TOC removal. The WAO and homogeneous CWAO processes were carried out at the temperature from 433 K to 513 K, with initial oxygen pressure 1.2 MPa. It was found that homogeneous catalyst copper(Cu(NO3)2) had an fairly good catalytic activity for the WAO process, and the oxidation was catalyzed when the temperature was higher than 473 K. Moreover, several heterogeneous catalysts were proved to be effective for the WAO process. At the temperature 473 K, after 2 h reaction, WAO process could achieve about 75% COD removal and 66% TOC removal, while catalysts Cu/Al2O3 and Mn-Ce/Al2O3 elevated the COD removal up to 86%--89% and that of TOC up to 82%. However, complete elimination of COD and TOC was proved to be difficult even the best non-noble catalyst was used. Therefore, the effluent from WAO or CWAO process need to be further disposed. The bioassay proved that the effluent from WAO process was amenable to the biochemical method. PMID:16158582

  2. Air Flow and Pressure Drop Measurements Across Porous Oxides

    NASA Technical Reports Server (NTRS)

    Fox, Dennis S.; Cuy, Michael D.; Werner, Roger A.

    2008-01-01

    This report summarizes the results of air flow tests across eight porous, open cell ceramic oxide samples. During ceramic specimen processing, the porosity was formed using the sacrificial template technique, with two different sizes of polystyrene beads used for the template. The samples were initially supplied with thicknesses ranging from 0.14 to 0.20 in. (0.35 to 0.50 cm) and nonuniform backside morphology (some areas dense, some porous). Samples were therefore ground to a thickness of 0.12 to 0.14 in. (0.30 to 0.35 cm) using dry 120 grit SiC paper. Pressure drop versus air flow is reported. Comparisons of samples with thickness variations are made, as are pressure drop estimates. As the density of the ceramic material increases the maximum corrected flow decreases rapidly. Future sample sets should be supplied with samples of similar thickness and having uniform surface morphology. This would allow a more consistent determination of air flow versus processing parameters and the resulting porosity size and distribution.

  3. Air Quality Criteria for Sulfur Oxides.

    ERIC Educational Resources Information Center

    National Air Pollution Control Administration (DHEW), Washington, DC.

    Included is a literature review which comprehensively discusses knowledge of the sulfur oxides commonly found in the atmosphere. The subject content is represented by the 10 chapter titles: Physical and Chemical Properties and the Atmospheric Reactions of the Oxides of Sulfur; Sources and Methods of Measurements of Sulfur Oxides in the Atmosphere;…

  4. AIRS Maps from Space Processing Software

    NASA Technical Reports Server (NTRS)

    Thompson, Charles K.; Licata, Stephen J.

    2012-01-01

    This software package processes Atmospheric Infrared Sounder (AIRS) Level 2 swath standard product geophysical parameters, and generates global, colorized, annotated maps. It automatically generates daily and multi-day averaged colorized and annotated maps of various AIRS Level 2 swath geophysical parameters. It also generates AIRS input data sets for Eyes on Earth, Puffer-sphere, and Magic Planet. This program is tailored to AIRS Level 2 data products. It re-projects data into 1/4-degree grids that can be combined and averaged for any number of days. The software scales and colorizes global grids utilizing AIRS-specific color tables, and annotates images with title and color bar. This software can be tailored for use with other swath data products for the purposes of visualization.

  5. Low Temperature Processed Complementary Metal Oxide Semiconductor (CMOS) Device by Oxidation Effect from Capping Layer

    PubMed Central

    Wang, Zhenwei; Al-Jawhari, Hala A.; Nayak, Pradipta K.; Caraveo-Frescas, J. A.; Wei, Nini; Hedhili, M. N.; Alshareef, H. N.

    2015-01-01

    In this report, both p- and n-type tin oxide thin-film transistors (TFTs) were simultaneously achieved using single-step deposition of the tin oxide channel layer. The tuning of charge carrier polarity in the tin oxide channel is achieved by selectively depositing a copper oxide capping layer on top of tin oxide, which serves as an oxygen source, providing additional oxygen to form an n-type tin dioxide phase. The oxidation process can be realized by annealing at temperature as low as 190°C in air, which is significantly lower than the temperature generally required to form tin dioxide. Based on this approach, CMOS inverters based entirely on tin oxide TFTs were fabricated. Our method provides a solution to lower the process temperature for tin dioxide phase, which facilitates the application of this transparent oxide semiconductor in emerging electronic devices field. PMID:25892711

  6. Low temperature processed complementary metal oxide semiconductor (CMOS) device by oxidation effect from capping layer.

    PubMed

    Wang, Zhenwei; Al-Jawhari, Hala A; Nayak, Pradipta K; Caraveo-Frescas, J A; Wei, Nini; Hedhili, M N; Alshareef, H N

    2015-04-20

    In this report, both p- and n-type tin oxide thin-film transistors (TFTs) were simultaneously achieved using single-step deposition of the tin oxide channel layer. The tuning of charge carrier polarity in the tin oxide channel is achieved by selectively depositing a copper oxide capping layer on top of tin oxide, which serves as an oxygen source, providing additional oxygen to form an n-type tin dioxide phase. The oxidation process can be realized by annealing at temperature as low as 190 °C in air, which is significantly lower than the temperature generally required to form tin dioxide. Based on this approach, CMOS inverters based entirely on tin oxide TFTs were fabricated. Our method provides a solution to lower the process temperature for tin dioxide phase, which facilitates the application of this transparent oxide semiconductor in emerging electronic devices field.

  7. Surface oxidation under ambient air--not only a fast and economical method to identify double bond positions in unsaturated lipids but also a reminder of proper lipid processing.

    PubMed

    Zhou, Ying; Park, Hyejung; Kim, Philseok; Jiang, Yan; Costello, Catherine E

    2014-06-17

    A simple, fast approach elucidated carbon-carbon double bond positions in unsaturated lipids. Lipids were deposited onto various surfaces and the products from their oxidation in ambient air were observed by electrospray ionization (ESI) mass spectrometry (MS). The most common oxidative products, aldehydes, were detected as transformations at the cleaved double bond positions. Ozonides and carboxylic acids were generated in certain lipids. Investigations of the conditions controlling the appearance of these products indicated that the surface oxidation depends on light and ambient air. Since the lipid oxidation was slower in a high concentration of ozone, singlet oxygen appeared to be a parallel oxidant for unsaturated lipids. The 3-hydroxyl group in the sphingoid base of sulfatides offered some protection from oxidation for the Δ4,5-double bond, slowing its oxidation rate relative to that of the isolated double bond in the N-linked fatty acyl chain. Direct sampling by thin-layer chromatography (TLC)-ESI-MS provides a powerful approach to elucidate detailed structural information on biological samples. Co-localization of the starting lipids and their oxidation products after TLC separation allowed assignment of the native unsaturation sites. Phosphatidylserine and N,N-dimethyl phosphatidylethanolamine isomers in a bovine brain total lipid extract were distinguished on the basis of their oxidation products. Meanwhile, the findings reported herein reveal a potential pitfall in the assignment of structures to lipids extracted from TLC plates because of artifactual oxidation after the plate development.

  8. Processing AIRS Scientific Data Through Level 2

    NASA Technical Reports Server (NTRS)

    Oliphant, Robert; Lee, Sung-Yung; Chahine, Moustafa; Susskind, Joel; arnet, Christopher; McMillin, Larry; Goldberg, Mitchell; Blaisdell, John; Rosenkranz, Philip; Strow, Larrabee

    2007-01-01

    The Atmospheric Infrared Spectrometer (AIRS) Science Processing System (SPS) is a collection of computer programs, denoted product generation executives (PGEs), for processing the readings of the AIRS suite of infrared and microwave instruments orbiting the Earth aboard NASA s Aqua spacecraft. AIRS SPS at an earlier stage of development was described in "Initial Processing of Infrared Spectral Data' (NPO-35243), NASA Tech Briefs, Vol. 28, No. 11 (November 2004), page 39. To recapitulate: Starting from level 0 (representing raw AIRS data), the PGEs and their data products are denoted by alphanumeric labels (1A, 1B, and 2) that signify the successive stages of processing. The cited prior article described processing through level 1B (the level-2 PGEs were not yet operational). The level-2 PGEs, which are now operational, receive packages of level-1B geolocated radiance data products and produce such geolocated geophysical atmospheric data products such as temperature and humidity profiles. The process of computing these geophysical data products is denoted "retrieval" and is quite complex. The main steps of the process are denoted microwave-only retrieval, cloud detection and cloud clearing, regression, full retrieval, and rapid transmittance algorithm.

  9. Reaction rate constant for dry air oxidation of K Basin fuel

    SciTech Connect

    Trimble, D.J.

    1998-04-29

    The rate of oxidation of spent nuclear fuel stored in the K Basin water is an important parameter when assessing the processes and accident scenarios for preparing the fuel for dry storage. The literature provides data and rate laws for the oxidation of unirradiated uranium in various environments. Measurement data for the dry air oxidation of K Basin fuel is compared to the literature data for linear oxidation in dry air. Equations for the correlations and statistical bounds to the K Basin fuel data and the literature data are selected for predicting nominal and bounding rates for the dry air oxidation of the K Basin fuel. These rate equations are intended for use in the Spent Nuclear Fuel Project Technical Data book.

  10. Microgravity Processing of Oxide Superconductors

    NASA Technical Reports Server (NTRS)

    Olive, James R.; Hofmeister, William H.; Bayuzick, Robert J.; Vlasse, Marcus

    1999-01-01

    Considerable effort has been concentrated on the synthesis and characterization of high T(sub c) oxide superconducting materials. The YBaCuO system has received the most intense study, as this material has shown promise for the application of both thin film and bulk materials. There are many problems with the application of bulk materials- weak links, poor connectivity, small coherence length, oxygen content and control, environmental reactivity, phase stability, incongruent melting behavior, grain boundary contamination, brittle mechanical behavior, and flux creep. The extent to which these problems are intrinsic or associated with processing is the subject of controversy. This study seeks to understand solidification processing of these materials, and to use this knowledge for alternative processing strategies, which, at the very least, will improve the understanding of bulk material properties and deficiencies. In general, the phase diagram studies of the YBaCuO system have concentrated on solid state reactions and on the Y2BaCuO(x) + liquid yields YBa2Cu3O(7-delta) peritectic reaction. Little information is available on the complete melting relations, undercooling, and solidification behavior of these materials. In addition, rare earth substitutions such as Nd and Gd affect the liquidus and phase relations. These materials have promising applications, but lack of information on the high temperature phase relations has hampered research. In general, the understanding of undercooling and solidification of high temperature oxide systems lags behind the science of these phenomena in metallic systems. Therefore, this research investigates the fundamental melting relations, undercooling, and solidification behavior of oxide superconductors with an emphasis on improving ground based synthesis of these materials.

  11. Microgravity Processing of Oxide Superconductors

    NASA Technical Reports Server (NTRS)

    Hofmeister, William H.; Bayuzick, Robert J.; Vlasse, Marcus; McCallum, William; Peters, Palmer (Technical Monitor)

    2000-01-01

    The primary goal is to understand the microstructures which develop under the nonequilibrium solidification conditions achieved by melt processing in copper oxide superconductor systems. More specifically, to define the liquidus at the Y- 1:2:3 composition, the Nd-1:2:3 composition, and several intermediate partial substitution points between pure Y-1:2:3 and Nd-1:2:3. A secondary goal has been to understand resultant solidification morphologies and pathways under a variety of experimental conditions and to use this knowledge to better characterize solidification phenomena in these systems.

  12. 75 FR 57463 - Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Oxides...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-21

    ... AGENCY Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Oxides... Ambient Air Quality Standards for Oxides of Nitrogen and Oxides of Sulfur: Second External Review Draft... for oxides of nitrogen (NO X ) and oxides of sulfur (SO X ). Because NO X , SO X , and...

  13. 75 FR 11877 - Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Oxides...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-12

    ... AGENCY Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Oxides... Ambient Air Quality Standards for Oxides of Nitrogen and Oxides of Sulfur: First External Review Draft... (welfare-based) NAAQS for oxides of nitrogen (NO X ) and oxides of sulfur (SO X ). Because NO X , SO...

  14. Melatonin involvement in oxidative processes.

    PubMed

    Ianăş, O; Olinescu, R; Bădescu, I

    1991-01-01

    The fact that the pineal gland, by its melatonin (MT) production, responds to environmental light variations (the day-night cycle), being also a modulator of the body adaptation to these conditions, may lead to the assumption of its involvement in the body oxidative processes. The redox capacity of melatonin was followed-up in vitro by the chemiluminescence phenomenon. The system generating chemiluminescence as well as free radicals was made up of luminol and H2O2. Incubation of melatonin in doses of 0.08-0.5 microM/ml with the generating system showed that in doses under 0.25 microM/ml melatonin has a pro-oxidative effect while in doses above this value it has an antioxidative effect. The diagram of the results shows the answer specific to a modulator. The study of the correlation between the dose of melatonin with highest pro-oxidative properties and the various peroxide concentrations in the generating system showed that melatonin gets antioxidative properties with the increase in peroxide concentrations (less than 8 mM/ml). In the presence of a hypothalamic homogenate, which is a stimulant of the chemiluminescence-generating system (PXI = 16), melatonin has a dose-dependent antioxidative effect. Similar results were also obtained by adding tryptophan--a free radicals acceptor (PXI = 0.1) and the substrate in melatonin synthesis to the reaction medium. Melatonin in low concentrations (greater than 0.1 microM/ml) has an antioxidative effect while in higher doses it has a dose-dependent pro-oxidative effect.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1821072

  15. The Oxides of Nitrogen in Air Pollution.

    ERIC Educational Resources Information Center

    California State Air Resources Board, Sacramento.

    Research on the health effects of oxides of nitrogen and on the role of oxides of nitrogen in producing photochemical smog effects is presented in this report. Prepared by the California State Department of Public Health at the request of the State Legislature, it gives a comprehensive review of available information, as well as the need for air…

  16. AIR POLLUTION, OXIDATIVE STRESS AND NEUROTOXICITY.

    EPA Science Inventory

    Increased incidents of classic and variant forms of neurodegenerative diseases suggest that environmental chemicals and susceptibility factors (e.g., genetics, diseased states, obesity, etc.) may be contributory. Particulate matter (PM) is a type of air pollution that is associat...

  17. Air side contamination in Solid Oxide Fuel Cell stack testing

    NASA Astrophysics Data System (ADS)

    Schuler, J. Andreas; Gehrig, Christian; Wuillemin, Zacharie; Schuler, Albert J.; Wochele, Joerg; Ludwig, Christian; Hessler-Wyser, Aïcha; Van herle, Jan

    This work aimed to quantify air side contaminants during Solid Oxide Fuel Cell (SOFC) testing in stack configuration. Post-analyses of a long-term test have shown that performance degradation was mainly due to cathode pollutants originated upstream of the cell, therefore their source identification is crucial. The compressed air system, feeding the airflow to the cathode, was investigated by filtering and subsequent chemical analysis of the filters. Hot-air-sampling was redone in situ at the cathode air entry during a new test run to assess the contaminant concentrations in air in SOFC test conditions. In addition, the behavior of SOFC proximal system components, i.e. alloy oxidation, was characterized separately. Besides the investigation of silicon and sulfur contamination, the present work focused on chromium from high-temperature alloys used in Balance-of-Plant (BoP) components in direct contact with the airflow. Concentrations of volatile Cr-species under SOFC testing conditions were compared to Cr-accumulation on the tested cell as well as to Cr-evaporation rates from BoP alloys, which were individually characterized regarding oxidation behavior. Evaporated Cr quantities were found to saturate the air with Cr-vapors at the cathode air-inlet, as confirmed by the in-situ measurement of volatile species in the hot airflow, and correlate well to accumulated Cr in the cell after long term testing. The results of this study suggest guidelines to reduce air side contamination from exogenous sources in SOFC stacks.

  18. Degradation of paracetamol by catalytic wet air oxidation and sequential adsorption - Catalytic wet air oxidation on activated carbons.

    PubMed

    Quesada-Peñate, I; Julcour-Lebigue, C; Jáuregui-Haza, U J; Wilhelm, A M; Delmas, H

    2012-06-30

    The concern about the fate of pharmaceutical products has raised owing to the increasing contamination of rivers, lakes and groundwater. The aim of this paper is to evaluate two different processes for paracetamol removal. The catalytic wet air oxidation (CWAO) of paracetamol on activated carbon was investigated both as a water treatment technique using an autoclave reactor and as a regenerative treatment of the carbon after adsorption in a sequential fixed bed process. Three activated carbons (ACs) from different source materials were used as catalysts: two microporous basic ACs (S23 and C1) and a meso- and micro-porous acidic one (L27). During the first CWAO experiment the adsorption capacity and catalytic performance of fresh S23 and C1 were higher than those of fresh L27 despite its higher surface area. This situation changed after AC reuse, as finally L27 gave the best results after five CWAO cycles. Respirometry tests with activated sludge revealed that in the studied conditions the use of CWAO enhanced the aerobic biodegradability of the effluent. In the ADOX process L27 also showed better oxidation performances and regeneration efficiency. This different ageing was examined through AC physico-chemical properties.

  19. A review of wet air oxidation and Thermal Hydrolysis technologies in sludge treatment.

    PubMed

    Hii, Kevin; Baroutian, Saeid; Parthasarathy, Raj; Gapes, Daniel J; Eshtiaghi, Nicky

    2014-03-01

    With rapid world population growth and strict environmental regulations, increasingly large volumes of sludge are being produced in today's wastewater treatment plants (WWTP) with limited disposal routes. Sludge treatment has become an essential process in WWTP, representing 50% of operational costs. Sludge destruction and resource recovery technologies are therefore of great ongoing interest. Hydrothermal processing uses unique characteristics of water at elevated temperatures and pressures to deconstruct organic and inorganic components of sludge. It can be broadly categorized into wet oxidation (oxidative) and thermal hydrolysis (non-oxidative). While wet air oxidation (WAO) can be used for the final sludge destruction and also potentially producing industrially useful by-products such as acetic acid, thermal hydrolysis (TH) is mainly used as a pre-treatment method to improve the efficiency of anaerobic digestion. This paper reviews current hydrothermal technologies, roles of wet air oxidation and thermal hydrolysis in sludge treatment, and challenges faced by these technologies.

  20. Process for Producing Metal Compounds From Graphite Oxide

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh (Inventor)

    2000-01-01

    A process for providing elemental metals or metal oxides distributed on a carbon substrate or self-supported utilizing graphite oxide as a precursor. The graphite oxide is exposed to one or more metal chlorides to form an intermediary product comprising carbon, metal, chloride, and oxygen. This intermediary product can be fiber processed by direct exposure to carbonate solutions to form a second intermediary product comprising carbon. metal carbonate. and oxygen. Either intermediary product may be further processed: a) in air to produce metal oxide b) in an inert environment to produce metal oxide on carbon substrate; c) in a reducing environment to produce elemental metal distributed on carbon substrate. The product generally takes the shape of the carbon precursor.

  1. Process for producing metal compounds from graphite oxide

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh (Inventor)

    2000-01-01

    A process for providing elemental metals or metal oxides distributed on a carbon substrate or self-supported utilizing graphite oxide as a precursor. The graphite oxide is exposed to one or more metal chlorides to form an intermediary product comprising carbon, metal, chloride, and oxygen This intermediary product can be flier processed by direct exposure to carbonate solutions to form a second intermediary product comprising carbon, metal carbonate, and oxygen. Either intermediary product may be further processed: a) in air to produce metal oxide; b) in an inert environment to produce metal oxide on carbon substrate; c) in a reducing environment to produce elemental metal distributed on carbon substrate. The product generally takes the shape of the carbon precursor.

  2. Process for Producing Metal Compounds from Graphite Oxide

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh (Inventor)

    2000-01-01

    A process for providing elemental metals or metal oxides distributed on a carbon substrate or self-supported utilizing graphite oxide as a precursor. The graphite oxide is exposed to one or more metal chlorides to form an intermediary product comprising carbon. metal. chloride. and oxygen This intermediary product can be flier processed by direct exposure to carbonate solutions to form a second intermediary product comprising carbon. metal carbonate. and oxygen. Either intermediary product may be further processed: a) in air to produce metal oxide: b) in an inert environment to produce metal oxide on carbon substrate: c) in a reducing environment. to produce elemental metal distributed on carbon substrate. The product generally takes the shape of the carbon precursor.

  3. Protein oxidation at the air-lung interface.

    PubMed

    Kelly, F J; Mudway, I S

    2003-12-01

    Whilst performing its normal functions the lung is required to deal with a range of toxic insults. Whether these are infectious agents, allergens or air pollutants they subject the lung to a range of direct and indirect oxidative stresses. In many instances these challenges lead to oxidative alterations of peptides and proteins within the lung. Measurement of protein oxidation products permits the degree of oxidative stress to be assessed and indicates that endogenous antioxidant defences are overwhelmed. The range of protein oxidation products observed is diverse and the nature and extent of specific oxidation products may inform us about the nature of the damaging ROS and NOS. Recently, there has been a significant shift away from the measurement of these oxidation products simply to establish the presence of oxidative stress, to a focus on identifying specific proteins sensitive to oxidation and establishing the functional consequences of these modifications. In addition the identification of specific enzyme systems to repair these oxidative modifications has lead to the belief that protein function may be regulated through these oxidation reactions. In this review we focus primarily on the soluble protein components of within the surface liquid layer in the lung and the consequence of their undue oxidation.

  4. Effect of microstructure on air oxidation resistance of nuclear graphite

    SciTech Connect

    Contescu, Cristian I; Guldan, Tyler R; Wang, Peng; Burchell, Timothy D

    2012-01-01

    Oxidation resistance in air of three grades of nuclear graphite with different structures was compared using a standard thermogravimetric method. Differences in the oxidation behavior have been identified with respect to both (i) the rate of oxidation in identical conditions and the derived apparent activation energy and pre-exponential factor and (ii) the penetration depth of the oxidant and the development of the oxidized layer. These differences were ascribed to structural differences between the three graphite grades, in particular the grain size and shape of the graphite filler, and the associated textural properties, such as total BET surface area and porosity distribution in the un-oxidized material. It was also found that the amount of strongly bonded surface oxygen complexes measured by thermodesorption significantly exceeds the amount afforded by the low BET surface area, and therefore low temperature oxygen chemisorption is not a reliable method for determining the amount of surface sites (re)active during air oxidation. The relationship between nuclear graphite microstructure and its oxidation resistance demonstrated in this work underlines the importance of performing comprehensive oxidation characterization studies of the new grades of nuclear graphite considered as candidates for very high temperature gas-cooled reactors.

  5. Thermal Stabilization of Polycubes by Air Oxidation Results of Testing Unirradiated Polystyrene

    SciTech Connect

    BARNEY, G.S.

    2000-05-01

    Polystyrene samples were tested to determine if the polycubes stored at the Plutonium Finishing Plant could be stabilized safely by a thermal air oxidation process using existing production furnaces. Polycubes are compression-molded mixtures of plutonium oxide and/or uranium oxide in a polystyrene matrix. The irradiated polystyrene that forms the matrix of the polycubes will be high and crosslinked because of radiolysis. The behavior of the crosslinked polystyrene used in most of the tests reported here (polystyrene--8% divinyl benzene) appears to imitate polystyrene crosslinked by radiation. This material is more stable toward pyrolysis, is more reactive with oxygen, and produces more carbonaceous char and less flammable gas during oxidation than non-crosslinked polystyrene. The testing showed that air oxidation of polystyrene begins when it is heated to about 200 C in air. The more highly crosslinked polystyrene is oxidized more complete, and at lower temperatures. Pyrolysis is first observed at about 350 C in air and both oxidation and pyrolysis reactions occur simultaneously until about 420 C is reached, where the remaining carbonaceous chnr begins to oxidize. Oxidation is essentially complete in air at about 550 C. The gases evolved in the early stages of heating are mainly oxidation products (water, carbon dioxide, and benzaldehyde). When pyrolysis begins, a mixture of these oxidation products and hydrocarbon pyrolysis products (styrene, benzene, toluene, and indane) are evolved. The char oxidation step yields only carbon dioxide and water. The overall yields of gas were about 87% by weight oxidation products and 13% pyrolysis products. Concentrations of flammable hydrocarbon pyrolysis gases under normal operating conditions are estimated to be less than 5% of the lower Flammability limit. Benzaldehyde concentrations could be as high as 46% of the lower flammability limit, depending on the heating rate and the number of polycubes being processed. These

  6. Effect of fuel/air nonuniformity on nitric oxide emissions

    NASA Technical Reports Server (NTRS)

    Lyons, V. J.

    1979-01-01

    A flame tube combustor holding jet A fuel was used in experiments performed at a pressure of .3 Mpa and a reference velocity of 25 meters/second for three inlet air temperatures of 600, 700, and 800 K. The gas sample measurements were taken at locations 18 cm and 48 cm downstream of the perforated plate flameholder. Nonuniform fuel/air profiles were produced using a fuel injector by separately fueling the inner five fuel tubes and the outer ring of twelve fuel tubes. Six fuel/air profiles were produced for nominal overall equivalence ratios of .5 and .6. An example of three of three of these profiles and their resultant nitric oxide NOx emissions are presented. The uniform fuel/air profile cases produced uniform and relatively low profile levels. When the profiles were either center-peaked or edge-peaked, the overall mass-weighted nitric oxide levels increased.

  7. Treatment of trichlorophenol by catalytic oxidation process.

    PubMed

    Chu, W; Law, C K

    2003-05-01

    The oxidation of 2,4,6-trichlorophenol (TCP) by ferrous-catalyzed hydrogen peroxide was quantified and modeled in the study. TCP was effectively degraded by hydroxyl radicals that were generated by Fe(II)/H(2)O(2) in the oxidation process. The oxidation capacity (OC) of the process depends on the concentrations of oxidant (hydrogen peroxide) and oxidative catalyst (ferrous ion). Up to 99.6% of TCP removal can be achieved in the process, provided the doses of Fe(II) and H(2)O(2) are selected correctly. The OC of the process was successfully predicted through a kinetic approach in a two-stage model with some simple and measurable parameters, which makes the model useful for predicting, controlling and optimizing the catalyzed oxidation process in the degradation of TCP. PMID:12727243

  8. INTEGRATION OF PHOTOCATALYTIC OXIDATION WITH AIR STRIPPING OF CONTAMINATED AQUIFERS

    EPA Science Inventory

    Bench scale laboratory studies and pilot scale studies in a simulated field-test situation were performed to evaluate the integration of gas-solid ultaviolet (UV) photocatalytic oxidation (PCO) downstream if an air stripper unit as a technology for cost-effectively treating water...

  9. HOMOGENEOUS AIR OXIDATION OF HYDROCARBONS UTILIZING MN AND CO CATALYSTS

    EPA Science Inventory

    Homogeneous Air Oxidation of Hydrocarbons Utilizing Mn and Co Catalysts

    Thomas M. Becker and Michael A. Gonzalez*, Sustainable Technology Division, Office of Research and Development; United States Environmental Protection Agency, 26 West Martin Luther King Drive, Mail Sto...

  10. 75 FR 20595 - Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Oxides...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-20

    ... for Oxides of Nitrogen and Oxides of Sulfur: First External Review Draft (75 FR 11877; March 12, 2010... AGENCY Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Oxides... a proposal addressing the nitrogen oxides (NO X ) and sulfur oxides (SO X ) secondary...

  11. PROCESSES OF CHLORINATION OF URANIUM OXIDES

    DOEpatents

    Rosenfeld, S.

    1958-09-16

    An improvement is described in the process fur making UCl/sub 4/ from uranium oxide and carbon tetrachloride. In that process, oxides of uranium are contacted with carbon tetrachloride vapor at an elevated temperature. It has been fuund that the reaction product and yield are improved if the uranlum oxide charge is disposed in flat trays in the reaction zone, to a depth of not more than 1/2 centimeter.

  12. Accelerated oxidation processes is biodiesel

    SciTech Connect

    Canakci, M.; Monyem, A.; Van Gerpen, J.

    1999-12-01

    Biodiesel is an alternative fuel for diesel engines that can be produced from renewable feedstocks such as vegetable oil and animal fats. These feedstocks are reacted with an alcohol to produce alkyl monoesters that can be used in conventional diesel engines with little or no modification. Biodiesel, especially if produced from highly unsaturated oils, oxidizes more rapidly than diesel fuel. This article reports the results of experiments to track the chemical and physical changes that occur in biodiesel as it oxidizes. These results show the impact of time, oxygen flow rate, temperature, metals, and feedstock type on the rate of oxidation. Blending with diesel fuel and the addition of antioxidants are explored also. The data indicate that without antioxidants, biodiesel will oxidize very quickly at temperatures typical of diesel engines. This oxidation results in increases in peroxide value, acid value, and viscosity. While the peroxide value generally reaches a plateau of about 350 meq/kg ester, the acid value and viscosity increase monotonically as oxidation proceeds.

  13. Plutonium Oxide Process Capability Work Plan

    SciTech Connect

    Meier, David E.; Tingey, Joel M.

    2014-02-28

    Pacific Northwest National Laboratory (PNNL) has been tasked to develop a Pilot-scale Plutonium-oxide Processing Unit (P3U) providing a flexible capability to produce 200g (Pu basis) samples of plutonium oxide using different chemical processes for use in identifying and validating nuclear forensics signatures associated with plutonium production. Materials produced can also be used as exercise and reference materials.

  14. Process for recovering organic vapors from air

    DOEpatents

    Baker, Richard W.

    1985-01-01

    A process for recovering and concentrating organic vapor from a feed stream of air having an organic vapor content of no more than 20,000 ppm by volume. A thin semipermeable membrane is provided which has a feed side and a permeate side, a selectivity for organic vapor over air of at least 50, as measured by the ratio of organic vapor permeability to nitrogen permeability, and a permeability of organic vapor of at least 3.times.10.sup.-7 cm.sup.3 (STP) cm/cm.sup.2 sec.cm Hg. The feed stream is passed across the feed side of the thin semipermeable membrane while providing a pressure on the permeate side which is lower than the feed side by creating a partial vacuum on the permeate side so that organic vapor passes preferentially through the membrane to form an organic vapor depleted air stream on the feed side and an organic vapor enriched stream on the permeate side. The organic vapor which has passed through the membrane is compressed and condensed to recover the vapor as a liquid.

  15. Air-Impregnated Nanoporous Anodic Aluminum Oxide Layers for Enhancing the Corrosion Resistance of Aluminum.

    PubMed

    Jeong, Chanyoung; Lee, Junghoon; Sheppard, Keith; Choi, Chang-Hwan

    2015-10-13

    Nanoporous anodic aluminum oxide layers were fabricated on aluminum substrates with systematically varied pore diameters (20-80 nm) and oxide thicknesses (150-500 nm) by controlling the anodizing voltage and time and subsequent pore-widening process conditions. The porous nanostructures were then coated with a thin (only a couple of nanometers thick) Teflon film to make the surface hydrophobic and trap air in the pores. The corrosion resistance of the aluminum substrate was evaluated by a potentiodynamic polarization measurement in 3.5 wt % NaCl solution (saltwater). Results showed that the hydrophobic nanoporous anodic aluminum oxide layer significantly enhanced the corrosion resistance of the aluminum substrate compared to a hydrophilic oxide layer of the same nanostructures, to bare (nonanodized) aluminum with only a natural oxide layer on top, and to the latter coated with a thin Teflon film. The hydrophobic nanoporous anodic aluminum oxide layer with the largest pore diameter and the thickest oxide layer (i.e., the maximized air fraction) resulted in the best corrosion resistance with a corrosion inhibition efficiency of up to 99% for up to 7 days. The results demonstrate that the air impregnating the hydrophobic nanopores can effectively inhibit the penetration of corrosive media into the pores, leading to a significant improvement in corrosion resistance.

  16. Initial oxidation of brass induced by humidified air

    PubMed Central

    Qiu, Ping; Leygraf, Christofer

    2011-01-01

    Complementary surface and near-surface analytical techniques have been used to explore a brass (Cu–20Zn) surface before, during, and after exposure in air at 90% relative humidity. Volta potential variations along the unexposed surface are attributed to variations in surface composition and resulted in an accelerated localized growth of ZnO and a retarded more uniform growth of an amorphous Cu2O-like oxide. After 3 days the duplex oxide has a total mass of 1.3 μg/cm2, with improved corrosion protective properties compared to the oxides grown on pure Cu or Zn. A schematic model for the duplex oxide growth on brass is presented. PMID:23471205

  17. Initial oxidation of brass induced by humidified air

    NASA Astrophysics Data System (ADS)

    Qiu, Ping; Leygraf, Christofer

    2011-11-01

    Complementary surface and near-surface analytical techniques have been used to explore a brass (Cu-20Zn) surface before, during, and after exposure in air at 90% relative humidity. Volta potential variations along the unexposed surface are attributed to variations in surface composition and resulted in an accelerated localized growth of ZnO and a retarded more uniform growth of an amorphous Cu2O-like oxide. After 3 days the duplex oxide has a total mass of 1.3 μg/cm2, with improved corrosion protective properties compared to the oxides grown on pure Cu or Zn. A schematic model for the duplex oxide growth on brass is presented.

  18. Oxidation of delta-phase plutonium alloy: Corrosion kinetics in dry and humid air at 35 {degree}C

    SciTech Connect

    Haschke, J.M.

    1997-06-01

    Kinetic data for oxidation of delta-phase plutonium alloy are evaluated to provide a technical basis for assessing the merit of an existing time limitation on air exposure of components during process operations. Data describing the effects of humidity and oxygen pressure on the oxidation rate of the Pu-1.0 wt% Ga alloy at elevated temperatures are obtained from literature sources and used to predict the oxidation behavior of the alloy in air at 35 C and 0 to 100% relative humidity. A mandated six-hour limit on air exposure is inconsistent with a predicted thirty-day period required for formation of a 1-{micro}m-thick oxide layer in moisture-saturated air at 35 C. Relationships are defined for predicting kinetic behavior of the alloy at other conditions, and recommendations for addressing oxidation-related concerns in production are presented.

  19. Thermally grown oxide and diffusions for automatic processing of integrated circuits

    NASA Technical Reports Server (NTRS)

    Kennedy, B. W.

    1979-01-01

    A totally automated facility for semiconductor oxidation and diffusion was developed using a state-of-the-art diffusion furnace and high temperature grown oxides. Major innovations include: (1) a process controller specifically for semiconductor processing; (2) an automatic loading system to accept wafers from an air track, insert them into a quartz carrier and then place the carrier on a paddle for insertion into the furnace; (3) automatic unloading of the wafers back onto the air track, and (4) boron diffusion using diborane with plus or minus 5 percent uniformity. Processes demonstrated include Wet and dry oxidation for general use and for gate oxide, boron diffusion, phosphorous diffusion, and sintering.

  20. Nitric oxide density measurements in air and air/fuel nanosecond pulse discharges by laser induced fluorescence

    NASA Astrophysics Data System (ADS)

    Uddi, M.; Jiang, N.; Adamovich, I. V.; Lempert, W. R.

    2009-04-01

    Laser induced fluorescence is used to measure absolute nitric oxide concentrations in air, methane-air and ethylene-air non-equilibrium plasmas, as a function of time after initiation of a single pulse, 20 kV peak voltage, 25 ns pulse duration discharge. A mixture of NO and nitrogen with known composition (4.18 ppm NO) is used for calibration. Peak NO density in air at 60 Torr, after a single pulse, is ~8 × 1012 cm-3 (~4.14 ppm) occurring at ~250 µs after the pulse, with decay time of ~16.5 ms. Peak NO atom mole fraction in a methane-air mixture with equivalence ratio of phiv = 0.5 is found to be approximately equal to that in air, with approximately the same rise and decay rate. In an ethylene-air mixture (also with equivalence ratio of phiv = 0.5), the rise and decay times are comparable to air and methane-air, but the peak NO concentration is reduced by a factor of approximately 2.5. Spontaneous emission measurements show that excited electronic states N2(C 3Π) and NO(A 2Σ) in air at P = 60 Torr decay within ~20 ns and ~1 µs, respectively. Kinetic modelling calculations incorporating air plasma kinetics complemented with the GRI Mech 3.0 hydrocarbon oxidation mechanism are compared with the experimental data using three different NO production mechanisms. It is found that NO concentration rise after the discharge pulse is much faster than predicted by Zel'dovich mechanism reactions, by two orders of magnitude, but much slower compared with reactions of electronically excited nitrogen atoms and molecules, also by two orders of magnitude. It is concluded that processes involving long lifetime (~100 µs) metastable states, such as N2(X 1Σ,v) and O2(b 1Σ), formed by quenching of the metastable N2(A 3Σ) state by ground electronic state O2, may play a dominant role in NO formation. NO decay, in all cases, is found to be dominated by the reverse Zel'dovich reaction, NO + O → N + O2, as well as by conversion into NO2 in a reaction of NO with ozone.

  1. Cyclic Oxidation of High-Temperature Alloy Wires in Air

    NASA Technical Reports Server (NTRS)

    Reigel, Marissa M.

    2004-01-01

    High-temperature alloy wires are proposed for use in seal applications for future re-useable space vehicles. These alloys offer the potential for improved wear resistance of the seals. The wires must withstand the high temperature environments the seals are subjected to as well as maintain their oxidation resistance during the heating and cooling cycles of vehicle re-entry. To model this, the wires were subjected to cyclic oxidation in stagnant air. of this layer formation is dependent on temperature. Slow growing oxides such as chromia and alumina are desirable. Once the oxide is formed it can prevent the metal from further reacting with its environment. Cyclic oxidation models the changes in temperature these wires will undergo in application. Cycling the temperature introduces thermal stresses which can cause the oxide layer to break off. Re-growth of the oxide layer consumes more metal and therefore reduces the properties and durability of the material. were used for cyclic oxidation testing. The baseline material, Haynes 188, has a Co base and is a chromia former while the other two alloys, Kanthal A1 and PM2000, both have a Fe base and are alumina formers. Haynes 188 and Kanthal A1 wires are 250 pm in diameter and PM2000 wires are 150 pm in diameter. The coiled wire has a total surface area of 3 to 5 sq cm. The wires were oxidized for 11 cycles at 1204 C, each cycle containing a 1 hour heating time and a minimum 20 minute cooling time. Weights were taken between cycles. After 11 cycles, one wire of each composition was removed for analysis. The other wire continued testing for 70 cycles. Post-test analysis includes X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) for phase identification and morphology.

  2. Air electrode composition for solid oxide fuel cell

    DOEpatents

    Kuo, Lewis; Ruka, Roswell J.; Singhal, Subhash C.

    1999-01-01

    An air electrode composition for a solid oxide fuel cell is disclosed. The air electrode material is based on lanthanum manganite having a perovskite-like crystal structure ABO.sub.3. The A-site of the air electrode composition comprises a mixed lanthanide in combination with rare earth and alkaline earth dopants. The B-site of the composition comprises Mn in combination with dopants such as Mg, Al, Cr and Ni. The mixed lanthanide comprises La, Ce, Pr and, optionally, Nd. The rare earth A-site dopants preferably comprise La, Nd or a combination thereof, while the alkaline earth A-site dopant preferably comprises Ca. The use of a mixed lanthanide substantially reduces raw material costs in comparison with compositions made from high purity lanthanum starting materials. The amount of the A-site and B-site dopants is controlled in order to provide an air electrode composition having a coefficient of thermal expansion which closely matches that of the other components of the solid oxide fuel cell.

  3. Air electrode composition for solid oxide fuel cell

    DOEpatents

    Kuo, L.; Ruka, R.J.; Singhal, S.C.

    1999-08-03

    An air electrode composition for a solid oxide fuel cell is disclosed. The air electrode material is based on lanthanum manganite having a perovskite-like crystal structure ABO{sub 3}. The A-site of the air electrode composition comprises a mixed lanthanide in combination with rare earth and alkaline earth dopants. The B-site of the composition comprises Mn in combination with dopants such as Mg, Al, Cr and Ni. The mixed lanthanide comprises La, Ce, Pr and, optionally, Nd. The rare earth A-site dopants preferably comprise La, Nd or a combination thereof, while the alkaline earth A-site dopant preferably comprises Ca. The use of a mixed lanthanide substantially reduces raw material costs in comparison with compositions made from high purity lanthanum starting materials. The amount of the A-site and B-site dopants is controlled in order to provide an air electrode composition having a coefficient of thermal expansion which closely matches that of the other components of the solid oxide fuel cell. 3 figs.

  4. Evaluation of the TCE catalytic oxidation unit at Wurtsmith Air Force Base

    SciTech Connect

    Hylton, T.D. ); Marchand, E.G. )

    1991-01-01

    Remediation of VOC-contaminated groundwater is frequently performed by air stripping, a process that transfers the contaminants from the water phase to the air phase by contacting the phases countercurrently through a packed-bed column. Air stripping has proven to be effective and economic for removing volatile organic compounds (VOCs) from groundwater; in many cases, however, the states require the use of an emissions control device, such as a catalytic oxidation unit or a catalytic incinerator, in conjunction with the air stripping unit. Incineration is an attractive choice for emissions control since the contaminants are destroyed on site. Wurtsmith Air Force Base is the site of an air-stripping-with-emissions-control system to remove VOCs, chiefly trichloroethylene (TCE), from groundwater. A fluidized-bed catalytic oxidation unit treats the air stream to destroy the organic contaminants. The purpose of this study was to evaluate the performance of this unit and its catalyst for destroying halogenated organics with respect to catalyst bed temperature and operating time. The objectives included identification of any products of incomplete combustion formed and determination of the utility costs for the unit. Samples were collected over a period of {approximately}19 months with volatile organic sampling trains according to EPA Method 30. Samples were taken at catalyst bed temperatures of 315, 370, 425, and 480{degree}C. The results indicate that the incinerator was destroying the TCE with >97% efficiency when operated at 370{degree}C or greater. 6 refs., 9 figs., 2 tabs.

  5. Mechanism of Air Oxidation of the Fragrance Terpene Geraniol.

    PubMed

    Bäcktorp, Carina; Hagvall, Lina; Börje, Anna; Karlberg, Ann-Therese; Norrby, Per-Ola; Nyman, Gunnar

    2008-01-01

    The fragrance terpene geraniol autoxidizes upon air exposure and forms a mixture of oxidation products, some of which are skin sensitizers. Reactions of geraniol with O2 have been studied with DFT (B3LYP) and the computational results compared to experimentally observed product ratios. The oxidation is initiated by hydrogen abstraction, forming an allylic radical which combines with an O2 molecule to yield an intermediate peroxyl radical. In the subsequent step, geraniol differs from previously studied cases, in which the radical chain reaction is propagated through intermolecular hydrogen abstraction. The hydroxy-substituted allylic peroxyl radical prefers an intramolecular rearrangement, producing observable aldehydes and the hydroperoxyl radical, which in turn can propagate the radical reaction. Secondary oxidation products like epoxides and formates were also considered, and plausible reaction pathways for formation are proposed. PMID:26619983

  6. Process for catalytically oxidizing cycloolefins, particularly cyclohexene

    DOEpatents

    Mizuno, Noritaka; Lyon, David K.; Finke, Richard G.

    1993-01-01

    This invention is a process for catalytically oxidizing cycloolefins, particularly cyclohexenes, to form a variety of oxygenates. The catalyst used in the process is a covalently bonded iridium-heteropolyanion species. The process uses the catalyst in conjunction with a gaseous oxygen containing gas to form 2-cyclohexen-1-ol and also 2-cyclohexen-1-one.

  7. Microwave processing of ceramic oxide filaments

    SciTech Connect

    Vogt, G.J.; Katz, J.D.

    1995-05-01

    The objective of the microwave filament processing project is to develop microwave techniques at 2.45 GHZ to manufacture continuous ceramic oxide filaments. Microwave processing uses the volumetric absorption of microwave power in oxide filament tows to drive off process solvents, to burn out organic binders, and to sinter the dried fibers to produce flexible, high-strength ceramic filaments. The technical goal is to advance filament processing technology by microwave heating more rapidly with less energy and at a lower cost than conventional processing, but with the same quality as conventional processing. The manufacturing goal is to collaborate with the 3M Company, a US manufacturer of ceramic oxide filaments, to evaluate the technology using a prototype filament system and to transfer the microwave technology to the 3M Company.

  8. Treatment of high-strength industrial wastewater by wet air oxidation--A case study

    SciTech Connect

    Lin, S.H.; Ho, S.J.

    1997-12-31

    Treatment of high concentration chemical wastewater obtained from a petrochemical company by wet air oxidation (WAO) is studied. Experiments were conducted to investigate the effects of the mixer speed, operating pressure, initial pH of wastewater and temperature on the pollutant (chemical oxygen demand or COD) removal. Both air and oxygen were tested to determine their respective effect on the COD removal. Results showed that over 50% of COD removal can be easily realized in an hour of WAO treatment. Also considered in the present study was the catalytic WAO treatment of the high concentration wastewater. Copper sulfate (CuSO{sub 4}), cobalt oxide (Co{sub 2}O{sub 3}) and zinc oxide (ZnO) were employed as the catalysts. The COD removal efficiency of the catalytic WAO process was found to vary significantly with the catalyst utilized with CuSO{sub 4} being the most effective.

  9. Impact of Air Pollutants on Oxidative Stress in Common Autophagy-Mediated Aging Diseases

    PubMed Central

    Numan, Mohamed Saber; Brown, Jacques P.; Michou, Laëtitia

    2015-01-01

    Atmospheric pollution-induced cellular oxidative stress is probably one of the pathogenic mechanisms involved in most of the common autophagy-mediated aging diseases, including neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), Alzheimer’s, disease, as well as Paget’s disease of bone with or without frontotemporal dementia and inclusion body myopathy. Oxidative stress has serious damaging effects on the cellular contents: DNA, RNA, cellular proteins, and cellular organelles. Autophagy has a pivotal role in recycling these damaged non-functional organelles and misfolded or unfolded proteins. In this paper, we highlight, through a narrative review of the literature, that when autophagy processes are impaired during aging, in presence of cumulative air pollution-induced cellular oxidative stress and due to a direct effect on air pollutant, autophagy-mediated aging diseases may occur. PMID:25690002

  10. DESCRIPTION OF ATMOSPHERIC TRANSPORT PROCESSES IN EULERIAN AIR QUALITY MODELS

    EPA Science Inventory

    Key differences among many types of air quality models are the way atmospheric advection and turbulent diffusion processes are treated. Gaussian models use analytical solutions of the advection-diffusion equations. Lagrangian models use a hypothetical air parcel concept effecti...

  11. Dissolved air-flotation processes. Technical report

    SciTech Connect

    Krofta, M.; Wang, L.K.

    1986-11-05

    The theories and applications of various dissolved-air-flotation clarifiers (Supracell, Sandfloat, Floatpress, and Sedifloat) are presented. Supracell is a high-rate dissolved-air-flotation clarifier with only 3 to 5 minutes of detention time. Major application of Supracell is industrial-effluent treatment. Sandfloat is a package plant consisting of flocculation, dissolved-air floatation and automatic backwash filtration, and designed for either potable water treatment or tertiary wastewater-treatment. Sedifloat is a wastewater-treatment package plant consisting of both sedimentation and dissolved-air flotation. Floatpress consists of both dissolved air flotation and filter press and is specifically designed for sludge thickening. A Krofta Bargefloat is a floating lake-water clarification plant designed for acid-rain neutralization, phosphorus removal, algae removal and lake-water purification. Bargefloat has built-in chemical feeders, flocculator, dissolved-air-flotation clarifier and sand filter on a barge.

  12. Air-nitric acid destructive oxidation of organic wastes

    SciTech Connect

    Smith, J.R.

    1993-09-01

    Many organic materials have been completely oxidized to CO{sub 2}, CO, and inorganic acids in a 0.1M HNO{sub 3}/14.8M H{sub 3}PO{sub 4} solution with air sparging. Addition of 0.001M Pd{sub +2} reduces the CO to near 1% of the released carbon gases. To accomplish complete oxidation the solution temperature must be maintained above 130--150{degrees}C. Organic materials quantitatively destroyed include neoprene, cellulose, EDTA, TBP, tartaric acid, and nitromethane. The oxidation is usually complete in a few hours for soluble organic materials. The oxidation rate for non-aliphatic organic solids is moderately fast and surface area dependent. The rate for aliphatic organic compounds (polyethylene, PVC, and n-dodecane) is relatively very slow. This is due to the large energy required to abstract a hydrogen atom from these compounds, 99 kcal/mole. The combination of NO{sub 2}{center_dot} and H{center_dot} to produce HNO{sub 2} releases only 88 kcal/mole. Under conditions of high NO{sub 2}{center_dot} concentration it should be possible to oxidize these aliphatic compounds.

  13. Assessment of methanol electro-oxidation for direct methanol-air fuel cells

    SciTech Connect

    Fritts, S.D.; Sen, R.K.

    1988-07-01

    The Office of Energy Storage and Distribution of the US Department of Energy (DOE) supports the development of a methanol-air fuel cell for transportation application. The approach used at Los Alamos National Laboratory converts the methanol fuel to a hydrogen-rich gas in a reformer, then operates the fuel cell on hydrogen and air. The reformer tends to be bulky (raising vehicle packaging problems), has a long startup period, and is not well suited for the transient operation required in a vehicle. Methanol, however, can be oxidized electrochemically in the fuel cell. If this process can be conducted efficiently, a direct methanol-air fuel cell can be used, which does not require a reformer. The objective of this study is to assess the potential of developing a suitable catalyst for the direct electrochemical oxidation of methanol. The primary conclusion of this study is that no acceptable catalysts exist can efficiently oxidize methanol electrochemically and have the desired cost and lifetime for vehicle applications. However, recent progress in understanding the mechanism of methanol oxidation indicates that a predictive base can be developed to search for methanol oxidation catalysts and can be used to methodically develop improved catalysts. Such an approach is strongly recommended. The study also recommends that until further progress in developing high-performance catalysts is achieved, research in cell design and testing is not warranted. 43 refs., 12 figs., 1 tab.

  14. Processes regulating nitric oxide emissions from soils.

    PubMed

    Pilegaard, Kim

    2013-07-01

    Nitric oxide (NO) is a reactive gas that plays an important role in atmospheric chemistry by influencing the production and destruction of ozone and thereby the oxidizing capacity of the atmosphere. NO also contributes by its oxidation products to the formation of acid rain. The major sources of NO in the atmosphere are anthropogenic emissions (from combustion of fossil fuels) and biogenic emission from soils. NO is both produced and consumed in soils as a result of biotic and abiotic processes. The main processes involved are microbial nitrification and denitrification, and chemodenitrification. Thus, the net result is complex and dependent on several factors such as nitrogen availability, organic matter content, oxygen status, soil moisture, pH and temperature. This paper reviews recent knowledge on processes forming NO in soils and the factors controlling its emission to the atmosphere. Schemes for simulating these processes are described, and the results are discussed with the purpose of scaling up to global emission.

  15. Processes regulating nitric oxide emissions from soils.

    PubMed

    Pilegaard, Kim

    2013-07-01

    Nitric oxide (NO) is a reactive gas that plays an important role in atmospheric chemistry by influencing the production and destruction of ozone and thereby the oxidizing capacity of the atmosphere. NO also contributes by its oxidation products to the formation of acid rain. The major sources of NO in the atmosphere are anthropogenic emissions (from combustion of fossil fuels) and biogenic emission from soils. NO is both produced and consumed in soils as a result of biotic and abiotic processes. The main processes involved are microbial nitrification and denitrification, and chemodenitrification. Thus, the net result is complex and dependent on several factors such as nitrogen availability, organic matter content, oxygen status, soil moisture, pH and temperature. This paper reviews recent knowledge on processes forming NO in soils and the factors controlling its emission to the atmosphere. Schemes for simulating these processes are described, and the results are discussed with the purpose of scaling up to global emission. PMID:23713124

  16. Processes regulating nitric oxide emissions from soils

    PubMed Central

    Pilegaard, Kim

    2013-01-01

    Nitric oxide (NO) is a reactive gas that plays an important role in atmospheric chemistry by influencing the production and destruction of ozone and thereby the oxidizing capacity of the atmosphere. NO also contributes by its oxidation products to the formation of acid rain. The major sources of NO in the atmosphere are anthropogenic emissions (from combustion of fossil fuels) and biogenic emission from soils. NO is both produced and consumed in soils as a result of biotic and abiotic processes. The main processes involved are microbial nitrification and denitrification, and chemodenitrification. Thus, the net result is complex and dependent on several factors such as nitrogen availability, organic matter content, oxygen status, soil moisture, pH and temperature. This paper reviews recent knowledge on processes forming NO in soils and the factors controlling its emission to the atmosphere. Schemes for simulating these processes are described, and the results are discussed with the purpose of scaling up to global emission. PMID:23713124

  17. Process for etching mixed metal oxides

    DOEpatents

    Ashby, C.I.H.; Ginley, D.S.

    1994-10-18

    An etching process is described using dicarboxylic and tricarboxylic acids as chelating etchants for mixed metal oxide films such as high temperature superconductors and ferroelectric materials. Undesirable differential etching rates between different metal oxides are avoided by selection of the proper acid or combination of acids. Feature sizes below one micron, excellent quality vertical edges, and film thicknesses in the 100 Angstrom range may be achieved by this method. 1 fig.

  18. Process for etching mixed metal oxides

    DOEpatents

    Ashby, Carol I. H.; Ginley, David S.

    1994-01-01

    An etching process using dicarboxylic and tricarboxylic acids as chelating etchants for mixed metal oxide films such as high temperature superconductors and ferroelectric materials. Undesirable differential etching rates between different metal oxides are avoided by selection of the proper acid or combination of acids. Feature sizes below one micron, excellent quality vertical edges, and film thicknesses in the 100 Angstom range may be achieved by this method.

  19. Reduction of metal oxides through mechanochemical processing

    DOEpatents

    Froes, Francis H.; Eranezhuth, Baburaj G.; Senkov, Oleg N.

    2000-01-01

    The low temperature reduction of a metal oxide using mechanochemical processing techniques. The reduction reactions are induced mechanically by milling the reactants. In one embodiment of the invention, titanium oxide TiO.sub.2 is milled with CaH.sub.2 to produce TiH.sub.2. Low temperature heat treating, in the range of 400.degree. C. to 700.degree. C., can be used to remove the hydrogen in the titanium hydride.

  20. Correlation between the microstructures of graphite oxides and their catalytic behaviors in air oxidation of benzyl alcohol.

    PubMed

    Geng, Longlong; Wu, Shujie; Zou, Yongcun; Jia, Mingjun; Zhang, Wenxiang; Yan, Wenfu; Liu, Gang

    2014-05-01

    A series of graphite oxide (GO) materials were obtained by thermal treatment of oxidized natural graphite powder at different temperatures (from 100 to 200 °C). The microstructure evolution (i.e., layer structure and surface functional groups) of the graphite oxide during the heating process is studied by various characterization means, including XRD, N2 adsorption, TG-DTA, in situ DRIFT, XPS, Raman, TEM and Boehm titration. The characterization results show that the structures of GO materials change gradually from multilayer sheets to a transparent ultrathin 2D structure of the carbon sheets. The concentration of surface COH and HOCO groups decrease significantly upon treating temperature increasing. Benzyl alcohol oxidation with air as oxidant source was carried out to detect the catalytic behaviors of different GO materials. The activities of GO materials decrease with the increase of treating temperatures. It shows that the structure properties, including ultrathin sheets and high specific surface area, are not crucial factors affecting the catalytic activity. The type and amount of surface oxygen-containing functional groups of GO materials tightly correlates with the catalytic performance. Carboxylic groups on the surface of GO should act as oxidative sites for benzyl alcohol and the reduced form could be reoxidized by molecular oxygen.

  1. Solid oxide electrochemical cell fabrication process

    DOEpatents

    Dollard, Walter J.; Folser, George R.; Pal, Uday B.; Singhal, Subhash C.

    1992-01-01

    A method to form an electrochemical cell (12) is characterized by the steps of thermal spraying stabilized zirconia over a doped lanthanum manganite air electrode tube (14) to provide an electrolyte layer (15), coating conductive particles over the electrolyte, pressurizing the outside of the electrolyte layer, feeding halide vapors of yttrium and zirconium to the outside of the electrolyte layer and feeding a source of oxygen to the inside of the electrolyte layer, heating to cause oxygen reaction with the halide vapors to close electrolyte pores if there are any and to form a metal oxide coating on and between the particles and provide a fuel electrode (16).

  2. 40 CFR 50.17 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... standards for sulfur oxides (sulfur dioxide). 50.17 Section 50.17 Protection of Environment ENVIRONMENTAL....17 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level of the national primary 1-hour annual ambient air quality standard for oxides of sulfur is 75...

  3. 40 CFR 50.17 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... standards for sulfur oxides (sulfur dioxide). 50.17 Section 50.17 Protection of Environment ENVIRONMENTAL....17 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level of the national primary 1-hour annual ambient air quality standard for oxides of sulfur is 75...

  4. 40 CFR 50.17 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... standards for sulfur oxides (sulfur dioxide). 50.17 Section 50.17 Protection of Environment ENVIRONMENTAL....17 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level of the national primary 1-hour annual ambient air quality standard for oxides of sulfur is 75...

  5. 40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... standard for sulfur oxides (sulfur dioxide). 50.5 Section 50.5 Protection of Environment ENVIRONMENTAL....5 National secondary ambient air quality standard for sulfur oxides (sulfur dioxide). (a) The level... than 0.05 ppm shall be rounded up). (b) Sulfur oxides shall be measured in the ambient air as...

  6. 40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... standards for sulfur oxides (sulfur dioxide). 50.4 Section 50.4 Protection of Environment ENVIRONMENTAL....4 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level...). (c) Sulfur oxides shall be measured in the ambient air as sulfur dioxide by the reference...

  7. 40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... standards for sulfur oxides (sulfur dioxide). 50.4 Section 50.4 Protection of Environment ENVIRONMENTAL....4 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level...). (c) Sulfur oxides shall be measured in the ambient air as sulfur dioxide by the reference...

  8. 40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... standard for sulfur oxides (sulfur dioxide). 50.5 Section 50.5 Protection of Environment ENVIRONMENTAL....5 National secondary ambient air quality standard for sulfur oxides (sulfur dioxide). (a) The level... than 0.05 ppm shall be rounded up). (b) Sulfur oxides shall be measured in the ambient air as...

  9. 40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... standard for sulfur oxides (sulfur dioxide). 50.5 Section 50.5 Protection of Environment ENVIRONMENTAL....5 National secondary ambient air quality standard for sulfur oxides (sulfur dioxide). (a) The level... than 0.05 ppm shall be rounded up). (b) Sulfur oxides shall be measured in the ambient air as...

  10. 40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... standard for sulfur oxides (sulfur dioxide). 50.5 Section 50.5 Protection of Environment ENVIRONMENTAL....5 National secondary ambient air quality standard for sulfur oxides (sulfur dioxide). (a) The level... than 0.05 ppm shall be rounded up). (b) Sulfur oxides shall be measured in the ambient air as...

  11. 40 CFR 50.17 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... standards for sulfur oxides (sulfur dioxide). 50.17 Section 50.17 Protection of Environment ENVIRONMENTAL....17 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level of the national primary 1-hour annual ambient air quality standard for oxides of sulfur is 75...

  12. 40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... standards for sulfur oxides (sulfur dioxide). 50.4 Section 50.4 Protection of Environment ENVIRONMENTAL....4 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level...). (c) Sulfur oxides shall be measured in the ambient air as sulfur dioxide by the reference...

  13. 40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... standard for sulfur oxides (sulfur dioxide). 50.5 Section 50.5 Protection of Environment ENVIRONMENTAL....5 National secondary ambient air quality standard for sulfur oxides (sulfur dioxide). (a) The level... than 0.05 ppm shall be rounded up). (b) Sulfur oxides shall be measured in the ambient air as...

  14. 40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... standards for sulfur oxides (sulfur dioxide). 50.4 Section 50.4 Protection of Environment ENVIRONMENTAL....4 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level...). (c) Sulfur oxides shall be measured in the ambient air as sulfur dioxide by the reference...

  15. 40 CFR 50.17 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... standards for sulfur oxides (sulfur dioxide). 50.17 Section 50.17 Protection of Environment ENVIRONMENTAL....17 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level of the national primary 1-hour annual ambient air quality standard for oxides of sulfur is 75...

  16. Integrated catalytic wet air oxidation and biological treatment of wastewater from Vitamin B 6 production

    NASA Astrophysics Data System (ADS)

    Kang, Jianxiong; Zhan, Wei; Li, Daosheng; Wang, Xiaocong; Song, Jing; Liu, Dongqi

    This study investigated the feasibility of coupling a catalytic wet air oxidation (CWAO), with CuO/Al 2O 3 as catalyst, and an anaerobic/aerobic biological process to treat wastewater from Vitamin B 6 production. Results showed that the CWAO enhanced the biodegradability (BOD 5/COD) from 0.10 to 0.80. The oxidized effluents with COD of 10,000 mg l -1 was subjected to subsequent continuous anaerobic/aerobic oxidation, and 99.3% of total COD removal was achieved. The quality of the effluent obtained met the discharge standards of water pollutants for pharmaceutical industry Chemical Synthesis Products Category (GB21904-2008), and thereby it implies that the integrated CWAO and anaerobic/aerobic biological treatment may offer a promising process to treat wastewater from Vitamin B 6 production.

  17. Thermal imaging of solid oxide fuel cell anode processes

    NASA Astrophysics Data System (ADS)

    Pomfret, Michael B.; Steinhurst, Daniel A.; Kidwell, David A.; Owrutsky, Jeffrey C.

    A Si-charge-coupled device (CCD), camera-based, near-infrared imaging system is demonstrated on Ni/yttria-stabilized zirconia (YSZ) fragments and the anodes of working solid oxide fuel cells (SOFCs). NiO reduction to Ni by H 2 and carbon deposition lead to the fragment cooling by 5 ± 2 °C and 16 ± 1 °C, respectively. When air is flowed over the fragments, the temperature rises 24 ± 1 °C as carbon and Ni are oxidized. In an operational SOFC, the decrease in temperature with carbon deposition is only 4.0 ± 0.1 °C as the process is moderated by the presence of oxides and water. Electrochemical oxidation of carbon deposits results in a Δ T of +2.2 ± 0.2 °C, demonstrating that electrochemical oxidation is less vigorous than atmospheric oxidation. While the high temperatures of SOFCs are challenging in many respects, they facilitate thermal imaging because their emission overlaps the spectral response of inexpensive Si-CCD cameras. Using Si-CCD cameras has advantages in terms of cost, resolution, and convenience compared to mid-infrared thermal cameras. High spatial (∼0.1 mm) and temperature (∼0.1 °C) resolutions are achieved in this system. This approach provides a convenient and effective analytical technique for investigating the effects of anode chemistry in operating SOFCs.

  18. Combining Advanced Oxidation Processes: Assessment Of Process Additivity, Synergism, And Antagonism

    SciTech Connect

    Peters, Robert W.; Sharma, M.P.; Gbadebo Adewuyi, Yusuf

    2007-07-01

    This paper addresses the process interactions from combining integrated processes (such as advanced oxidation processes (AOPs), biological operations, air stripping, etc.). AOPs considered include: Fenton's reagent, ultraviolet light, titanium dioxide, ozone (O{sub 3}), hydrogen peroxide (H{sub 2}O{sub 2}), sonication/acoustic cavitation, among others. A critical review of the technical literature has been performed, and the data has been analyzed in terms of the processes being additive, synergistic, or antagonistic. Predictions based on the individual unit operations are made and compared against the behavior of the combined unit operations. The data reported in this paper focus primarily on treatment of petroleum hydrocarbons and chlorinated solvents. (authors)

  19. Novel imazethapyr detoxification applying advanced oxidation processes.

    PubMed

    Stathis, Ioannis; Hela, Dimitra G; Scrano, Laura; Lelario, Filomena; Emanuele, Lucia; Bufo, Sabino A

    2011-01-01

    Different degradation methods have been applied to assess the suitability of advanced oxidation process (AOPs) to promote mineralization of imazethapyr [(RS)-5-ethyl-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid], a widely used imidazolinone class herbicide, the persistence of which has been demonstrated in surface and ground waters destined to human uses. Independent of the oxidation process assessed, the decomposition of imazethapyr always followed a pseudo-first order kinetic. The direct UV-irradiation (UV) of the herbicide as well as its oxidation with ozone (O₃), and hydrogen peroxide tied to UV-irradiation (H₂O₂/UV) were sufficiently slow to permit the identification of intermediate products, the formation pathway of which has been proposed. Ozonation joined to UV-irradiation (O₃/UV), ozonation joined to titanium dioxide photo-catalysis (TiO₂/UV+O₃), sole photo-catalysis (TiO₂/UV), and photo-catalysis reinforced with hydrogen peroxide-oxidation (TiO₂/UV+H₂O₂) were characterized by a faster degradation and rapid formation of a lot of small molecules, which were quickly degraded to complete mineralization. The most effective oxidation methods were those using titanium dioxide photo-catalysis enhanced either by ozonation or hydrogen peroxide. Most of all, these last processes were useful to avoid the development of dangerous by-products. PMID:21726140

  20. Oxidative Allylic Esterification of Alkenes by Cooperative Selenium-Catalysis Using Air as the Sole Oxidant.

    PubMed

    Ortgies, Stefan; Depken, Christian; Breder, Alexander

    2016-06-17

    A new metal-free catalysis protocol for the oxidative coupling of nonactivated alkenes with simple carboxylic acids has been established. This method is predicated on the cooperative interaction of a diselane and a photoredox catalyst, which allows for the use of ambient air or pure O2 as the terminal oxidant. Under the title conditions, a range of both functionalized and nonfunctionalized alkenes can be readily converted into the corresponding allylic ester products with good yields (up to 89%) and excellent regioselectivity as well as good functional group tolerance.

  1. Oxidative Allylic Esterification of Alkenes by Cooperative Selenium-Catalysis Using Air as the Sole Oxidant.

    PubMed

    Ortgies, Stefan; Depken, Christian; Breder, Alexander

    2016-06-17

    A new metal-free catalysis protocol for the oxidative coupling of nonactivated alkenes with simple carboxylic acids has been established. This method is predicated on the cooperative interaction of a diselane and a photoredox catalyst, which allows for the use of ambient air or pure O2 as the terminal oxidant. Under the title conditions, a range of both functionalized and nonfunctionalized alkenes can be readily converted into the corresponding allylic ester products with good yields (up to 89%) and excellent regioselectivity as well as good functional group tolerance. PMID:27257803

  2. Alveolar macrophage cytokine response to air pollution particles: Oxidant mechanisms

    SciTech Connect

    Imrich, Amy; Ning Yaoyu; Lawrence, Joy; Coull, Brent; Gitin, Elena; Knutson, Mitchell; Kobzik, Lester . E-mail: lkobzik@hsph.harvard.edu

    2007-02-01

    Alveolar macrophages (AMs) primed with LPS and treated with concentrated ambient air particles (CAPs) showed enhanced release of tumor necrosis factor (TNF) and provide an in vitro model for the amplified effects of air pollution particles seen in people with preexisting lung disease. To investigate the mechanism(s) by which CAPs mediate TNF release in primed rat AMs, we first tested the effect of a panel of antioxidants. N-Acetyl-L-cysteine (20 mM), dimethyl thiourea (20 mM) and catalase (5 {mu}M) significantly inhibited TNF release by primed AMs incubated with CAPs. Conversely, when LPS-primed AMs were treated with CAPs in the presence of exogenous oxidants (H{sub 2}O{sub 2} generated by glucose oxidase, 10 {mu}M/h), TNF release and cell toxicity was significantly increased. The soluble fraction of CAPs suspensions caused most of the increased bioactivity in the presence of exogenous H{sub 2}O{sub 2}. The metal chelator deferoxamine (DFO) strongly inhibited the interaction of the soluble fraction with H{sub 2}O{sub 2} but had no effect on the bioactivity of the insoluble CAPs fraction. We conclude that CAPs can mediate their effects in primed AMs by acting on oxidant-sensitive cytokine release in at least two distinct ways. In the primed cell, insoluble components of PM mediate enhanced TNF production that is H{sub 2}O{sub 2}-dependent (catalase-sensitive) yet independent of iron (DFO-insensitive). In the presence of exogenous H{sub 2}O{sub 2} released by AMs, PMNs, or other lung cells within an inflamed alveolar milieu, soluble iron released from air particles can also mediate cytokine release and cell toxicity.

  3. Amine-Oxide Hybrid Materials for CO2 Capture from Ambient Air.

    PubMed

    Didas, Stephanie A; Choi, Sunho; Chaikittisilp, Watcharop; Jones, Christopher W

    2015-10-20

    Oxide supports functionalized with amine moieties have been used for decades as catalysts and chromatographic media. Owing to the recognized impact of atmospheric CO2 on global climate change, the study of the use of amine-oxide hybrid materials as CO2 sorbents has exploded in the past decade. While the majority of the work has concerned separation of CO2 from dilute mixtures such as flue gas from coal-fired power plants, it has been recognized by us and others that such supported amine materials are also perhaps uniquely suited to extract CO2 from ultradilute gas mixtures, such as ambient air. As unique, low temperature chemisorbents, they can operate under ambient conditions, spontaneously extracting CO2 from ambient air, while being regenerated under mild conditions using heat or the combination of heat and vacuum. This Account describes the evolution of our activities on the design of amine-functionalized silica materials for catalysis to the design, characterization, and utilization of these materials in CO2 separations. New materials developed in our laboratory, such as hyperbranched aminosilica materials, and previously known amine-oxide hybrid compositions, have been extensively studied for CO2 extraction from simulated ambient air (400 ppm of CO2). The role of amine type and structure (molecular, polymeric), support type and structure, the stability of the various compositions under simulated operating conditions, and the nature of the adsorbed CO2 have been investigated in detail. The requirements for an effective, practical air capture process have been outlined and the ability of amine-oxide hybrid materials to meet these needs has been discussed. Ultimately, the practicality of such a "direct air capture" process is predicated not only on the physicochemical properties of the sorbent, but also how the sorbent operates in a practical process that offers a scalable gas-solid contacting strategy. In this regard, the utility of low pressure drop monolith

  4. Amine-Oxide Hybrid Materials for CO2 Capture from Ambient Air.

    PubMed

    Didas, Stephanie A; Choi, Sunho; Chaikittisilp, Watcharop; Jones, Christopher W

    2015-10-20

    Oxide supports functionalized with amine moieties have been used for decades as catalysts and chromatographic media. Owing to the recognized impact of atmospheric CO2 on global climate change, the study of the use of amine-oxide hybrid materials as CO2 sorbents has exploded in the past decade. While the majority of the work has concerned separation of CO2 from dilute mixtures such as flue gas from coal-fired power plants, it has been recognized by us and others that such supported amine materials are also perhaps uniquely suited to extract CO2 from ultradilute gas mixtures, such as ambient air. As unique, low temperature chemisorbents, they can operate under ambient conditions, spontaneously extracting CO2 from ambient air, while being regenerated under mild conditions using heat or the combination of heat and vacuum. This Account describes the evolution of our activities on the design of amine-functionalized silica materials for catalysis to the design, characterization, and utilization of these materials in CO2 separations. New materials developed in our laboratory, such as hyperbranched aminosilica materials, and previously known amine-oxide hybrid compositions, have been extensively studied for CO2 extraction from simulated ambient air (400 ppm of CO2). The role of amine type and structure (molecular, polymeric), support type and structure, the stability of the various compositions under simulated operating conditions, and the nature of the adsorbed CO2 have been investigated in detail. The requirements for an effective, practical air capture process have been outlined and the ability of amine-oxide hybrid materials to meet these needs has been discussed. Ultimately, the practicality of such a "direct air capture" process is predicated not only on the physicochemical properties of the sorbent, but also how the sorbent operates in a practical process that offers a scalable gas-solid contacting strategy. In this regard, the utility of low pressure drop monolith

  5. Processing of effluent salt from the direct oxide reduction process

    SciTech Connect

    Mishra, B.; Olson, D.L. . Kroll Inst. for Extractive Metallurgy); Averill, W.A. )

    1992-01-01

    The production of reactive metals by Direct Oxide Reduction (DOR) process using calcium in a molten calcium salt system generates significant amount of contaminated waste as calcium oxide saturated calcium chloride salt mix with calcium oxide content of up to 15 wt. pct. Fused salt electrolysis of a simulated salt mix has been carried out to electrowin calcium, which can be recycled to the DOR reactor along with the calcium chloride salt or may be used in-situ in a combined DOR and electrowinning process. Many reactive metal oxides could thus be reduced in a one-step process without generating a significant amount of waste. The process has been optimized in terms of the calcium solubility, cell temperature, current density and the cell design to maximize the current efficiency. Based on the information available regarding the solubility of calcium in calcium chloride salt in the presence of calcium oxide, and the back reactions occurring in-situ between the electrowon calcium and other components present in the cell, e.g. carbon, oxygen, carbon dioxide and calcium oxide, it is difficult to recover elemental calcium within the system. However, a liquid cathode or a rising cathode has been used in the past to recover calcium. The solubility has also been found to depend on the use of graphite as the anode material as evidenced by the presence of calcium carbonate in the final salt. The rate of recovery for metallic calcium has to be enhanced to levels that overcome the back reactions in a system where quick removal of anodic gases is achieved. Calcium has been detected by the hydrogen evolution technique and the amount of calcia has been determined by titration. A porous ceramic sheath has been used in the cell to prevent the chemical reaction of electrowon calcium to produce oxide or carbonate and to prevent the contamination of salt by the anodic carbon.

  6. Processing of effluent salt from the direct oxide reduction process

    SciTech Connect

    Mishra, B.; Olson, D.L.; Averill, W.A.

    1992-05-01

    The production of reactive metals by Direct Oxide Reduction (DOR) process using calcium in a molten calcium salt system generates significant amount of contaminated waste as calcium oxide saturated calcium chloride salt mix with calcium oxide content of up to 15 wt. pct. Fused salt electrolysis of a simulated salt mix has been carried out to electrowin calcium, which can be recycled to the DOR reactor along with the calcium chloride salt or may be used in-situ in a combined DOR and electrowinning process. Many reactive metal oxides could thus be reduced in a one-step process without generating a significant amount of waste. The process has been optimized in terms of the calcium solubility, cell temperature, current density and the cell design to maximize the current efficiency. Based on the information available regarding the solubility of calcium in calcium chloride salt in the presence of calcium oxide, and the back reactions occurring in-situ between the electrowon calcium and other components present in the cell, e.g. carbon, oxygen, carbon dioxide and calcium oxide, it is difficult to recover elemental calcium within the system. However, a liquid cathode or a rising cathode has been used in the past to recover calcium. The solubility has also been found to depend on the use of graphite as the anode material as evidenced by the presence of calcium carbonate in the final salt. The rate of recovery for metallic calcium has to be enhanced to levels that overcome the back reactions in a system where quick removal of anodic gases is achieved. Calcium has been detected by the hydrogen evolution technique and the amount of calcia has been determined by titration. A porous ceramic sheath has been used in the cell to prevent the chemical reaction of electrowon calcium to produce oxide or carbonate and to prevent the contamination of salt by the anodic carbon.

  7. Composition of air pollution particles modifies oxidative stress in cells, tissues, and living systems

    EPA Science Inventory

    Epidemiological studies demonstrate an association between increased levels of ambient air pollution particles and human morbidity and mortality. Production of oxidants, either directly by the air pollution particles or by the host response to the particles, appears to be fundame...

  8. Process for preparing active oxide powders

    DOEpatents

    Berard, Michael F.; Hunter, Jr., Orville; Shiers, Loren E.; Dole, Stephen L.; Scheidecker, Ralph W.

    1979-02-20

    An improved process for preparing active oxide powders in which cation hydroxide gels, prepared in the conventional manner are chemically dried by alternately washing the gels with a liquid organic compound having polar characteristics and a liquid organic compound having nonpolar characteristics until the mechanical water is removed from the gel. The water-free cation hydroxide is then contacted with a final liquid organic wash to remove the previous organic wash and speed drying. The dried hydroxide treated in the conventional manner will form a highly sinterable active oxide powder.

  9. SPONTANEOUS CATALYTIC WET AIR OXIDATION DURING PRE-TREATMENT OF HIGH-LEVEL RADIOACTIVE WASTE SLUDGE

    SciTech Connect

    Koopman, D.; Herman, C.; Pareizs, J.; Bannochie, C.; Best, D.; Bibler, N.; Fellinger, T.

    2009-10-01

    Savannah River Remediation, LLC (SRR) operates the Defense Waste Processing Facility for the U.S. Department of Energy at the Savannah River Site. This facility immobilizes high-level radioactive waste through vitrification following chemical pretreatment. Catalytic destruction of formate and oxalate ions to carbon dioxide has been observed during qualification testing of non-radioactive analog systems. Carbon dioxide production greatly exceeded hydrogen production, indicating the occurrence of a process other than the catalytic decomposition of formic acid. Statistical modeling was used to relate the new reaction chemistry to partial catalytic wet air oxidation of both formate and oxalate ions driven by the low concentrations of palladium, rhodium, and/or ruthenium in the waste. Variations in process conditions led to increases or decreases in the total oxidative destruction, as well as partially shifting the preferred species undergoing destruction from oxalate ion to formate ion.

  10. Using advanced oxidation treatment for biofilm inactivation by varying water vapor content in air plasma

    NASA Astrophysics Data System (ADS)

    Ryota, Suganuma; Koichi, Yasuoka

    2015-09-01

    Biofilms are caused by environmental degradation in food factories and medical facilities. The inactivation of biofilms involves making them react with chemicals including chlorine, hydrogen peroxide, and ozone, although inactivation using chemicals has a potential problem because of the hazardous properties of the residual substance and hydrogen peroxide, which have slow reaction velocity. We successfully performed an advanced oxidation process (AOP) using air plasma. Hydrogen peroxide and ozone, which were used for the formation of OH radicals in our experiment, were generated by varying the amount of water vapor supplied to the plasma. By varying the content of the water included in the air, the main product was changed from air plasma. When we increased the water content in the air, hydrogen peroxide was produced, while ozone peroxide was produced when we decreased the water content in the air. By varying the amount of water vapor, we realized a 99.9% reduction in the amount of bacteria in the biofilm when we discharged humidified air only. This work was supported by JSPS KAKENHI Grant Number 25630104.

  11. Photocatalyzed oxidation of ethanol and acetaldehyde in humidified air

    SciTech Connect

    Sauer, M.L.; Ollis, D.F.

    1996-02-01

    Photocatalysis is considered as a potential air treatment and purification technology. Photocatalyzed oxidation of ethanol and acetaldehyde in humidified air was carried out to establish a first complete kinetic model for a photocatalyzed multispecies network. Two photocatalysts were examined in a batch, recirculation reactor, near-UV illuminated TiO{sub 2} (anatase) coated (i) on the surface of a nonporous quartz glass plate and (ii) on a porous ceramic honeycomb monolith. The former contained only illuminated (active) surfaces, the latter consisted of substantial {open_quotes}dark{close_quotes} surfaces coated with a thin layer of illuminated (active) catalyst. Ethanol was photooxidized to acetaldehyde and formaldehyde intermediates, and eventually to carbon dioxide and water products. The catalyst and monolith surfaces adsorbed appreciable fractions of the trace ethanol, acetaldehyde, formaldehyde, carbon dioxide and water present. Ethanol, acetaldehyde, and carbon dioxide adsorption isotherms were measured on both catalysts; the formaldehyde adsorption isotherms were assumed identical to those of acetaldehyde. On the fully illuminated glass plate reactor, all four species were accounted for, and closure of a transient carbon mass balance was demonstrated. Completion of a transient carbon mass balance on the monolith reactor required inclusion of additional reaction intermediates (acetic and formic acids), which appear to reversibly accumulate on only the dark surfaces. The ethanol and acetaldehyde photocatalyzed oxidation kinetic networks were modeled using Langmuir-Hinshelwood rate forms combined with adsorption isotherms for reactant, intermediates, and product CO{sub 2}. For both the quartz plate and monolith catalysts, satisfactory kinetic models were developed to predict the entire time course of ethanol and acetaldehyde multicomponent batch conversions. 43 refs., 16 figs.

  12. Formation and growth of indoor air aerosol particles as a result of D-limonene oxidation

    NASA Astrophysics Data System (ADS)

    Vartiainen, E.; Kulmala, M.; Ruuskanen, T. M.; Taipale, R.; Rinne, J.; Vehkamäki, H.

    Oxidation of D-limonene, which is a common monoterpene, can lead to new aerosol particle formation in indoor environments. Thus, products containing D-limonene, such as citrus fruits, air refresheners, household cleaning agents, and waxes, can act as indoor air aerosol particle sources. We released D-limonene into the room air by peeling oranges and measured the concentration of aerosol particles of three different size ranges. In addition, we measured the concentration of D-limonene, the oxidant, and the concentration of ozone, the oxidizing gas. Based on the measurements we calculated the growth rate of the small aerosol particles, which were 3-10 nm in diameter, to be about 6300nmh-1, and the losses of the aerosol particles that were due to the coagulation and condensation processes. From these, we further approximated the concentration of the condensable vapour and its source rate and then calculated the formation rate of the small aerosol particles. For the final result, we calculated the nucleation rate and the maximum number of molecules in a critical cluster. The nucleation rate was in the order of 105cm-3s-1 and the number of molecules in a critical-sized cluster became 1.2. The results were in agreement with the activation theory.

  13. Induced effects of advanced oxidation processes

    NASA Astrophysics Data System (ADS)

    Liu, Peng; Li, Chaolin; Zhao, Zhuanjun; Lu, Gang; Cui, Haibo; Zhang, Wenfang

    2014-02-01

    Hazardous organic wastes from industrial, military, and commercial activities represent one of the greatest challenges to human beings. Advanced oxidation processes (AOPs) are alternatives to the degradation of those organic wastes. However, the knowledge about the exact mechanisms of AOPs is still incomplete. Here we report a phenomenon in the AOPs: induced effects, which is a common property of combustion reaction. Through analysis EDTA oxidation processes by Fenton and UV-Fenton system, the results indicate that, just like combustion, AOPs are typical induction reactions. One most compelling example is that pre-feeding easily oxidizable organic matter can promote the oxidation of refractory organic compound when it was treated by AOPs. Connecting AOPs to combustion, it is possible to achieve some helpful enlightenment from combustion to analyze, predict and understand AOPs. In addition, we assume that maybe other oxidation reactions also have induced effects, such as corrosion, aging and passivation. Muchmore research is necessary to reveal the possibilities of induced effects in those fields.

  14. Induced effects of advanced oxidation processes

    PubMed Central

    Liu, Peng; Li, Chaolin; Zhao, Zhuanjun; Lu, Gang; Cui, Haibo; Zhang, Wenfang

    2014-01-01

    Hazardous organic wastes from industrial, military, and commercial activities represent one of the greatest challenges to human beings. Advanced oxidation processes (AOPs) are alternatives to the degradation of those organic wastes. However, the knowledge about the exact mechanisms of AOPs is still incomplete. Here we report a phenomenon in the AOPs: induced effects, which is a common property of combustion reaction. Through analysis EDTA oxidation processes by Fenton and UV-Fenton system, the results indicate that, just like combustion, AOPs are typical induction reactions. One most compelling example is that pre-feeding easily oxidizable organic matter can promote the oxidation of refractory organic compound when it was treated by AOPs. Connecting AOPs to combustion, it is possible to achieve some helpful enlightenment from combustion to analyze, predict and understand AOPs. In addition, we assume that maybe other oxidation reactions also have induced effects, such as corrosion, aging and passivation. Muchmore research is necessary to reveal the possibilities of induced effects in those fields. PMID:24503715

  15. Treatment of hydraulic fracturing wastewater by wet air oxidation.

    PubMed

    Wang, Wei; Yan, Xiuyi; Zhou, Jinghui; Ma, Jiuli

    2016-01-01

    Wastewater produced by hydraulic fracturing for oil and gas production is characterized by high salinity and high chemical oxygen demand (COD). We applied a combination of flocculation and wet air oxidation technology to optimize the reduction of COD in the treatment of hydraulic fracturing wastewater. The experiments used different values of flocculant, coagulant, and oxidizing agent added to the wastewater, as well as different reaction times and treatment temperatures. The use of flocculants for the pretreatment of fracturing wastewater was shown to improve treatment efficiency. The addition of 500 mg/L of polyaluminum chloride (PAC) and 20 mg/L of anionic polyacrylamide (APAM) during pretreatment resulted in a COD removal ratio of 8.2% and reduced the suspended solid concentration of fracturing wastewater to 150 mg/L. For a solution of pretreated fracturing wastewater with 12 mL of added H2O2, the COD was reduced to 104 mg/L when reacted at 300 °C for 75 min, and reduced to 127 mg/L when reacted at the same temperature for 45 min while using a 1 L autoclave. An optimal combination of these parameters produced treated wastewater that met the GB 8978-1996 'Integrated Wastewater Discharge Standard' level I emission standard. PMID:26942530

  16. Air Force research in optical processing

    NASA Technical Reports Server (NTRS)

    Neff, J.

    1981-01-01

    Optical and optical electronic hybrid processing especially in the application area of image processing are emphasized. Real time pattern recognition processors for such airborne missions as target recognition, tracking, and terminal guidance are studied.

  17. Catalysis of propane oxidation and premixed propane-air flames

    NASA Astrophysics Data System (ADS)

    Wiswall, James T.

    Improvements in deriving energy from hydrocarbon fuels will have a large impact on our efforts to transition to sustainable and renewable energy resources. The hypothesis for this work is that catalysis can extend the useful operating conditions for hydrocarbon oxidation and combustion, improve device efficiencies, and reduce pollutants. Catalysis of propane oxidation and premixed propane-air flames are examined experimentally, using a stagnation-flow reactor to identify the important physical and chemical mechanisms over a range of flow catalyst, and temperature conditions. The propane oxidation studies consider five catalyst materials: platinum, palladium, SnO2, 90% SnO2 -- 10% Pt (by mass), and quartz. The volume fractions of CO2, O2, C 3H8, CO, NO and the electric power required to control the catalyst temperature quantify the activity of each catalyst for the equivalence ratios of φ = 0.67, 1.00, and 1.50, and over the catalyst temperature range 23-800°C. Quartz is used as a baseline and confirmed to be non-reactive at all conditions. 100% SnO2 has minimal reactivity. Platinum, palladium, and 90% SnO2 -- 10% Pt show similar trends and have the highest catalytic activity at φ = 1.50. Palladium and 90% SnO 2 -- 10% Pt show an increasing catalyst-activation temperature (Tsa) for decreasing φ, and platinum shows an approximately constant catalyst-activation temperature for decreasing φ (Tsa = 310°C). Of these the 90% SnO2 -- 10% Pt catalyst shows the lowest Tsa, occurring for the φ = 1.5 mixture (Tsa = 250°C). The studies of premixed propane-air flames consider platinum and quartz stagnation surfaces for fuel-mixture velocities from 0.6-1.6 m/s. Five flame structures are observed: cool core envelope, cone, envelope, disk and ring flames. The lean-extinction limit, disk-to-ring flame transition φ, and the disk-flame to stagnation-plane distance are reported. Platinum inhibits the ring flame structure. The lean-extinction limit and disk-flame to stagnation

  18. Advanced oxidation process sanitization of eggshell surfaces.

    PubMed

    Gottselig, Steven M; Dunn-Horrocks, Sadie L; Woodring, Kristy S; Coufal, Craig D; Duong, Tri

    2016-06-01

    The microbial quality of eggs entering the hatchery represents an important critical control point for biosecurity and pathogen reduction programs in integrated poultry production. The development of safe and effective interventions to reduce microbial contamination on the surface of eggs will be important to improve the overall productivity and microbial food safety of poultry and poultry products. The hydrogen peroxide (H2O2) and ultraviolet (UV) light advanced oxidation process is a potentially important alternative to traditional sanitizers and disinfectants for egg sanitation. The H2O2/UV advanced oxidation process was demonstrated previously to be effective in reducing surface microbial contamination on eggs. In this study, we evaluated treatment conditions affecting the efficacy of H2O2/UV advanced oxidation in order to identify operational parameters for the practical application of this technology in egg sanitation. The effect of the number of application cycles, UV intensity, duration of UV exposure, and egg rotation on the recovery of total aerobic bacteria from the surface of eggs was evaluated. Of the conditions evaluated, we determined that reduction of total aerobic bacteria from naturally contaminated eggs was optimized when eggs were sanitized using 2 repeated application cycles with 5 s exposure to 14 mW cm(-2) UV light, and that rotation of the eggs between application cycles was unnecessary. Additionally, using these optimized conditions, the H2O2/UV process reduced Salmonella by greater than 5 log10 cfu egg(-1) on the surface of experimentally contaminated eggs. This study demonstrates the potential for practical application of the H2O2/UV advanced oxidation process in egg sanitation and its effectiveness in reducing Salmonella on eggshell surfaces. PMID:27030693

  19. Air Stripping Designs and Reactive Water Purification Processes for the Lunar Surface

    NASA Technical Reports Server (NTRS)

    Boul, Peter J.; Lange, Kevin; Conger, Bruce; Anderson, Molly

    2010-01-01

    Air stripping designs are considered to reduce the presence of volatile organic compounds in the purified water. Components of the wastewater streams are ranked by Henry's Law Constant and the suitability of air stripping in the purification of wastewater in terms of component removal is evaluated. Distillation processes are modeled in tandem with air stripping to demonstrate the potential effectiveness and utility of these methods in recycling wastewater on the Moon. Scaling factors for distillation and air stripping columns are presented to account for the difference in the lunar gravitation environment. Commercially available distillation and air stripping units which are considered suitable for Exploration Life Support are presented. The advantages to the various designs are summarized with respect to water purity levels, power consumption, and processing rates. An evaluation of reactive distillation and air stripping is presented with regards to the reduction of volatile organic compounds in the contaminated water and air. Among the methods presented, an architecture is presented for the evaluation of the simultaneous oxidation of organics in air and water. These and other designs are presented in light of potential improvements in power consumptions and air and water purities for architectures which include catalytic activity integrated into the water processor. In particular, catalytic oxidation of organics may be useful as a tool to remove contaminants that more traditional distillation and/or air stripping columns may not remove. A review of the current leading edge at the commercial level and at the research frontier in catalytically active materials is presented. Themes and directions from the engineering developments in catalyst design are presented conceptually in light of developments in the nanoscale chemistry of a variety of catalyst materials.

  20. Evaluation of a Combined Ultraviolet Photocatalytic Oxidation(UVPCO)/Chemisorbent Air Cleaner for Indoor Air Applications

    SciTech Connect

    Hodgson, Alfred T.; Destaillats, Hugo; Hotchi, Toshifumi; Fisk,William J.

    2007-02-01

    We previously reported that gas-phase byproducts of incomplete oxidation were generated when a prototype ultraviolet photocatalytic oxidation (UVPCO) air cleaner was operated in the laboratory with indoor-relevant mixtures of VOCs at realistic concentrations. Under these conditions, there was net production of formaldehyde and acetaldehyde, two important indoor air toxicants. Here, we further explore the issue of byproduct generation. Using the same UVPCO air cleaner, we conducted experiments to identify common VOCs that lead to the production of formaldehyde and acetaldehyde and to quantify their production rates. We sought to reduce the production of formaldehyde and acetaldehyde to acceptable levels by employing different chemisorbent scrubbers downstream of the UVPCO device. Additionally, we made preliminary measurements to estimate the capacity and expected lifetime of the chemisorbent media. For most experiments, the system was operated at 680-780 m{sup 3}/h (400-460 cfm). A set of experiments was conducted with common VOCs introduced into the UVPCO device individually and in mixture. Compound conversion efficiencies and the production of formaldehyde and acetaldehyde were determined by comparison of compound concentrations upstream and downstream of the reactor. There was general agreement between compound conversions efficiencies determined individually and in the mixture. This suggests that competition among compounds for active sites on the photocatalyst surface will not limit the performance of the UVPCO device when the total VOC concentration is low. A possible exception was the very volatile alcohols, for which there were some indications of competitive adsorption. The results also showed that formaldehyde was produced from many commonly encountered VOCs, while acetaldehyde was generated by specific VOCs, particularly ethanol. The implication is that formaldehyde concentrations are likely to increase when an effective UVPCO air cleaner is used in

  1. Thermal Processing and Microwave Processing of Mixed-Oxide Thin Films

    NASA Astrophysics Data System (ADS)

    Gadre, Mandar

    2011-12-01

    Amorphous oxide semiconductors are promising new materials for various optoelectronic applications. In this study, improved electrical and optical properties upon thermal and microwave processing of mixed-oxide semiconductors are reported. First, arsenic-doped silicon was used as a model system to understand susceptor-assisted microwave annealing. Mixed oxide semiconductor films of indium zinc oxide (IZO) and indium gallium zinc oxide (IGZO) were deposited by room-temperature RF sputtering on flexible polymer substrates. Thermal annealing in different environments---air, vacuum and oxygen was done. Electrical and optical characterization was carried out before and after annealing. The degree of reversal in the degradation in electrical properties of the thin films upon annealing in oxygen was assessed by subjecting samples to subsequent vacuum anneals. To further increase the conductivity of the IGZO films, Ag layers of various thicknesses were embedded between two IGZO layers. Optical performance of the multilayer structures was improved by susceptor-assisted microwave annealing and furnace-annealing in oxygen environment without compromising on their electrical conductivity. The post-processing of the films in different environments was used to develop an understanding of mechanisms of carrier generation, transport and optical absorption. This study establishes IGZO as a viable transparent conductor, which can be deposited at room-temperature and processed by thermal and microwave annealing to improve electrical and optical performance for applications in flexible electronics and optoelectronics.

  2. Treatment of plutonium process residues by molten salt oxidation

    SciTech Connect

    Stimmel, J.; Wishau, R.; Ramsey, K.B.; Montoya, A.; Brock, J.; Heslop, M.; Wernly, K.

    1999-04-01

    Molten Salt Oxidation (MSO) is a thermal process that can remove more than 99.999% of the organic matrix from combustible {sup 238}Pu material. Plutonium processing residues are injected into a molten salt bed with an excess of air. The salt (sodium carbonate) functions as a catalyst for the conversion of the organic material to carbon dioxide and water. Reactive species such as fluorine, chlorine, bromine, iodine, sulfur, phosphorous and arsenic in the organic waste react with the molten salt to form the corresponding neutralized salts, NaF, NaCl, NaBr, NaI, Na{sub 2}SO{sub 4}, Na{sub 3}PO{sub 4} and NaAsO{sub 2} or Na{sub 3}AsO4. Plutonium and other metals react with the molten salt and air to form metal salts or oxides. Saturated salt will be recycled and aqueous chemical separation will be used to recover the {sup 238}Pu. The Los Alamos National Laboratory system, which is currently in the conceptual design stage, will be scaled down from current systems for use inside a glovebox.

  3. Characterization of process air emissions in automotive production plants.

    PubMed

    D'Arcy, J B; Dasch, J M; Gundrum, A B; Rivera, J L; Johnson, J H; Carlson, D H; Sutherland, J W

    2016-01-01

    During manufacturing, particles produced from industrial processes become airborne. These airborne emissions represent a challenge from an industrial hygiene and environmental standpoint. A study was undertaken to characterize the particles associated with a variety of manufacturing processes found in the auto industry. Air particulates were collected in five automotive plants covering ten manufacturing processes in the areas of casting, machining, heat treatment and assembly. Collection procedures provided information on air concentration, size distribution, and chemical composition of the airborne particulate matter for each process and insight into the physical and chemical processes that created those particles.

  4. Oxidation resistance of selected mechanical carbons at 650 deg C in dry flowing air

    NASA Technical Reports Server (NTRS)

    Allen, G. P.; Wisander, D. W.

    1973-01-01

    Oxidation experiments were conducted with several experimental mechanical carbons at 650 C in air flowing at 28 cu cm/sec (STP). Experiments indicate that boron carbide addition and zinc phosphate treatment definitely improved oxidation resistance. Impregnation with coal tar pitch before final graphitization had some beneficial effect on oxidation resistance and it markedly improved flexure strength and hardness. Graphitization temperature alone did not affect oxidation resistance, but with enough added boron carbide the oxidation resistance was increased although the hardness greatly decreased.

  5. Organic waste processing using molten salt oxidation

    SciTech Connect

    Adamson, M. G., LLNL

    1998-03-01

    Molten Salt Oxidation (MSO) is a thermal means of oxidizing (destroying) the organic constituents of mixed wastes, hazardous wastes, and energetic materials while retaining inorganic and radioactive constituents in the salt. For this reason, MSO is considered a promising alternative to incineration for the treatment of a variety of organic wastes. The U. S. Department of Energy`s Office of Environmental Management (DOE/EM) is currently funding research that will identify alternatives to incineration for the treatment of organic-based mixed wastes. (Mixed wastes are defined as waste streams which have both hazardous and radioactive properties.) One such project is Lawrence Livermore National Laboratory`s Expedited Technology Demonstration of Molten Salt Oxidation (MSO). The goal of this project is to conduct an integrated demonstration of MSO, including off-gas and spent salt treatment, and the preparation of robust solid final forms. Livermore National Laboratory (LLNL) has constructed an integrated pilot-scale MSO treatment system in which tests and demonstrations are presently being performed under carefully controlled (experimental) conditions. The system consists of a MSO process vessel with dedicated off-gas treatment, a salt recycle system, feed preparation equipment, and equipment for preparing ceramic final waste forms. In this paper we describe the integrated system and discuss its capabilities as well as preliminary process demonstration data. A primary purpose of these demonstrations is to identify the most suitable waste streams and waste types for MSO treatment.

  6. Catalytic air oxidation of biomass-derived carbohydrates to formic acid.

    PubMed

    Li, Jiang; Ding, Dao-Jun; Deng, Li; Guo, Qing-Xiang; Fu, Yao

    2012-07-01

    An efficient catalytic system for biomass oxidation to form formic acid was developed. The conversion of glucose to formic acid can reach up to 52% yield within 3 h when catalyzed by 5 mol% of H(5)PV(2)Mo(10)O(40) at only 373 K using air as the oxidant. Furthermore, the heteropolyacid can be used as a bifunctional catalyst in the conversion of cellulose to formic acid (yield=35%) with air as the oxidant. PMID:22499553

  7. Catalytic air oxidation of biomass-derived carbohydrates to formic acid.

    PubMed

    Li, Jiang; Ding, Dao-Jun; Deng, Li; Guo, Qing-Xiang; Fu, Yao

    2012-07-01

    An efficient catalytic system for biomass oxidation to form formic acid was developed. The conversion of glucose to formic acid can reach up to 52% yield within 3 h when catalyzed by 5 mol% of H(5)PV(2)Mo(10)O(40) at only 373 K using air as the oxidant. Furthermore, the heteropolyacid can be used as a bifunctional catalyst in the conversion of cellulose to formic acid (yield=35%) with air as the oxidant.

  8. Air feed tube support system for a solid oxide fuel cell generator

    DOEpatents

    Doshi, Vinod B.; Ruka, Roswell J.; Hager, Charles A.

    2002-01-01

    A solid oxide fuel cell generator (12), containing tubular fuel cells (36) with interior air electrodes (18), where a supporting member (82) containing a plurality of holes (26) supports oxidant feed tubes (51), which pass from an oxidant plenum (52") into the center of the fuel cells, through the holes (26) in the supporting member (82), where a compliant gasket (86) around the top of the oxidant feed tubes and on top (28) of the supporting member (82) helps support the oxidant feed tubes and center them within the fuel cells, and loosen the tolerance for centering the air feed tubes.

  9. Selective-oxidation catalyst improves Claus process

    SciTech Connect

    Lagas, J.A.; Borsboom, J. ); Berben, P.H. )

    1988-10-10

    Increased SO/sub 2/ emissions. On a worldwide scale, the exploitation and processing of crude oil and natural gas have increased significantly during the past 30 years. This expansion has caused severe pollution problems, especially from sulfur dioxide emissions to the atmosphere. A new development for the well-known Claus process improves production of elemental sulfur from H/sub 2/S. The ''SuperClaus'' process involves a modification of the process-control system and the use of a newly developed selective-oxidation catalyst in the third reactor with the objective of achieving a 99% or 99.5% overall sulfur recovery (two versions) without further tail-gas cleanup. The catalyst for the new process was developed and tested on laboratory bench scale for more than 3 years. Based on the results, it was decided to test the process directly in a commercial unit. A three-stage, 100-t/d Claus plant in a natural-gas plant in the Federal Republic of Germany has been retrofitted to SuperClause. Since Jan. 21, the process has been successfully operated.

  10. 40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... standards for sulfur oxides (sulfur dioxide). 50.4 Section 50.4 Protection of Environment ENVIRONMENTAL....4 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). Link to an... to or greater than 0.005 ppm shall be rounded up). (c) Sulfur oxides shall be measured in the...

  11. Catalytic wet air oxidation of chlorophenols over supported ruthenium catalysts.

    PubMed

    Li, Ning; Descorme, Claude; Besson, Michèle

    2007-07-31

    A series of noble metal (Pt, Pd, Ru) loaded zirconia catalysts were evaluated in the catalytic wet air oxidation (CWAO) of mono-chlorophenols (2-CP, 3-CP, 4-CP) under relatively mild reaction conditions. Among the investigated noble metals, Ru appeared to be the best to promote the CWAO of CPs as far as incipient-wetness impregnation was used to prepare all the catalysts. The position of the chlorine substitution on the aromatic ring was also shown to have a significant effect on the CP reactivity in the CWAO over 3wt.% Ru/ZrO(2). 2-CP was relatively easier to degradate compared to 3-CP and 4-CP. One reason could be the higher adsorption of 2-CP on the catalyst surface. Further investigations suggested that 3wt.% Ru/ZrO(2) is a very efficient catalyst in the CWAO of 2-CP as far as high 2-CP conversion and TOC abatement could still be reached at even lower temperature (393K) and lower total pressure (3MPa). Additionally, the conversion of 2-CP was demonstrated to increase with the initial pH of the 2-CP solution. The dechlorination reaction is promoted at higher pH. In all cases, the adsorption of the reactants and the reaction intermediates was shown to play a major role. All parameters that would control the molecule speciation in solution or the catalyst surface properties would have a key effect. PMID:17513043

  12. Cast Stone Oxidation Front Evaluation: Preliminary Results For Samples Exposed To Moist Air

    SciTech Connect

    Langton, C. A.; Almond, P. M.

    2013-11-26

    Cr oxidation front (depth to which soluble Cr was detected) for the Cast Stone sample exposed for 68 days to ambient outdoor temperatures and humid air (total age of sample was 131 days) was determined to be about 35 mm below the top sample surface exposed. The Tc oxidation front, depth at which Tc was insoluble, was not determined. Interpretation of the results indicates that the oxidation front is at least 38 mm below the exposed surface. The sample used for this measurement was exposed to ambient laboratory conditions and humid air for 50 days. The total age of the sample was 98 days. Technetium appears to be more easily oxidized than Cr in the Cast Stone matrix. The oxidized forms of Tc and Cr are soluble and therefore leachable. Longer exposure times are required for both the Cr and Tc spiked samples to better interpret the rate of oxidation. Tc spiked subsamples need to be taken further from the exposed surface to better define and interpret the leachable Tc profile. Finally Tc(VII) reduction to Tc(IV) appears to occur relatively fast. Results demonstrated that about 95 percent of the Tc(VII) was reduced to Tc(IV) during the setting and very early stage setting for a Cast Stone sample cured 10 days. Additional testing at longer curing times is required to determine whether additional time is required to reduce 100 % of the Tc(VII) in Cast Stone or whether the Tc loading exceeded the ability of the waste form to reduce 100 % of the Tc(VII). Additional testing is required for samples cured for longer times. Depth discrete subsampling in a nitrogen glove box is also required to determine whether the 5 percent Tc extracted from the subsamples was the result of the sampling process which took place in air. Reduction capacity measurements (per the Angus-Glasser method) performed on depth discrete samples could not be correlated with the amount of chromium or technetium leached from the depth discrete subsamples or with the oxidation front inferred from soluble

  13. 75 FR 70258 - Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Oxides...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-17

    ... Nitrogen and Oxides of Sulfur: Second External Review Draft (75 FR 57463, September 21, 2010). The EPA... a later date (75 FR 61486, October 5, 2010). The supplementary materials were: an errata sheet for... AGENCY Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and...

  14. Laboratory flammability studies of mixtures of hydrogen, nitrous oxide, and air

    SciTech Connect

    Cashdollar, K L; Hertzberg, M; Zlochower, I A; Lucci, C E; Green, G M; Thomas, R A

    1992-06-26

    At the request of the Department of Energy and the Westinghouse Hanford Company, the Bureau of Mines has investigated the flammability of mixtures of hydrogen, nitrous oxide, and air. This work is relevant to the possible hazards of flammable gas generation from nuclear waste tanks at Hanford, WA. The tests were performed in a 120-L spherical chamber under both quiescent and turbulent conditions using both electric spark and pyrotechnic ignition sources. The data reported here for binary mixtures of hydrogen in air generally confirm the data of previous investigators, but they are more comprehensive than those reported previously. The results clarify to a greater extent the complications associated with buoyancy, turbulence, and selective diffusion. The data reported here for ternary mixtures of hydrogen and nitrous oxide in air indicate that small additions of nitrous oxide (relative to the amount of air) have little effect, but that higher concentrations of nitrous oxide (relative to air) significantly increase the explosion hazard.

  15. Effect of nitrogen doping on wetting and photoactive properties of laser processed zinc oxide-graphene oxide nanocomposite layers

    SciTech Connect

    György, E.; Pérez del Pino, A.; Logofatu, C.; Duta, A.; Isac, L.

    2014-07-14

    Zinc oxide-graphene oxide nanocomposite layers were submitted to laser irradiation in air or controlled nitrogen atmosphere using a frequency quadrupled Nd:YAG (λ = 266 nm, τ{sub FWHM} ≅ 3 ns, ν = 10 Hz) laser source. The experiments were performed in air at atmospheric pressure or in nitrogen at a pressure of 2 × 10{sup 4} Pa. The effect of the irradiation conditions, incident laser fluence value, and number of subsequent laser pulses on the surface morphology of the composite material was systematically investigated. The obtained results reveal that nitrogen incorporation improves significantly the wetting and photoactive properties of the laser processed layers. The kinetics of water contact angle variation when the samples are submitted to laser irradiation in nitrogen are faster than that of the samples irradiated in air, the surfaces becoming super-hydrophilic under UV light irradiation.

  16. Air stripping & photocatalytic oxidation: A winning team for groundwater remediation

    SciTech Connect

    Kittrell, J.R.; Quinlan, C.W.

    1995-09-01

    The Dover AFB Groundwater Reclamation Project demonstrated advanced technologies to control groundwater contamination, including comparisons of traditional countercurrent air atrippers to a crossflow air stripping technology. Another demonstration involved an advanced photocatalytic VOC destruction technology, which operates on the effluent air from the stripper. The combination of air stripping and photocatalytic destruction was shown to be effective for remediation of groundwater contaminated with chlorinated organic compounds, both because of its low cost and its ability to prevent toxic air emissions. A detailed performance comparison of stripper designs shows that the crossflow air stripper design was comparable in effectiveness to the conventional countercurrent air stripper at high air-to-water ratios, but at a substantially lower pressure drop.

  17. 40 CFR Appendix S to Part 50 - Interpretation of the Primary National Ambient Air Quality Standards for Oxides of Nitrogen...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Ambient Air Quality Standards for Oxides of Nitrogen (Nitrogen Dioxide) S Appendix S to Part 50 Protection... National Ambient Air Quality Standards for Oxides of Nitrogen (Nitrogen Dioxide) 1. General (a) This... national ambient air quality standards for oxides of nitrogen as measured by nitrogen dioxide (“NO2...

  18. 40 CFR Appendix S to Part 50 - Interpretation of the Primary National Ambient Air Quality Standards for Oxides of Nitrogen...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Ambient Air Quality Standards for Oxides of Nitrogen (Nitrogen Dioxide) S Appendix S to Part 50 Protection... National Ambient Air Quality Standards for Oxides of Nitrogen (Nitrogen Dioxide) 1. General (a) This... national ambient air quality standards for oxides of nitrogen as measured by nitrogen dioxide (“NO2...

  19. 40 CFR Appendix S to Part 50 - Interpretation of the Primary National Ambient Air Quality Standards for Oxides of Nitrogen...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Ambient Air Quality Standards for Oxides of Nitrogen (Nitrogen Dioxide) S Appendix S to Part 50 Protection... National Ambient Air Quality Standards for Oxides of Nitrogen (Nitrogen Dioxide) 1. General (a) This... national ambient air quality standards for oxides of nitrogen as measured by nitrogen dioxide (“NO2...

  20. 40 CFR Appendix S to Part 50 - Interpretation of the Primary National Ambient Air Quality Standards for Oxides of Nitrogen...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Ambient Air Quality Standards for Oxides of Nitrogen (Nitrogen Dioxide) S Appendix S to Part 50 Protection... National Ambient Air Quality Standards for Oxides of Nitrogen (Nitrogen Dioxide) 1. General (a) This... national ambient air quality standards for oxides of nitrogen as measured by nitrogen dioxide (“NO2...

  1. 40 CFR Appendix S to Part 50 - Interpretation of the Primary National Ambient Air Quality Standards for Oxides of Nitrogen...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Ambient Air Quality Standards for Oxides of Nitrogen (Nitrogen Dioxide) S Appendix S to Part 50 Protection... National Ambient Air Quality Standards for Oxides of Nitrogen (Nitrogen Dioxide) 1. General (a) This... national ambient air quality standards for oxides of nitrogen as measured by nitrogen dioxide (“NO2...

  2. Leaf photosynthetic and water-relations responses for 'Valencia' orange trees exposed to oxidant air pollution

    SciTech Connect

    Olszyk, D.M.; Takemoto, B.K.; Poe, M.

    1991-01-01

    Leaf responses were measured to test a hypothesis that reduced photosynthetic capacity and/or altered water relations were associated with reductions in yield for 'Valencia' orange trees (Citrus sinensis (L.), Osbeck) exposed to ambient oxidant air pollution. Exposures were continuous for 4 years to three levels of oxidants (in charcoal-filtered, half-filtered, and non-filtered air). Oxidants had no effect on net leaf photosynthetic rates or on photosynthetic pigment concentrations. A single set of measurements indicated that oxidants increased leaf starch concentrations (24%) prior to flowering, suggesting a change in photosynthate allocation. Leaves exposed to oxidants had small, but consistent, changes in water relations over the summer growing season, compared to trees growing in filtered air. Other changes included decreased stomatal conductance (12%) and transpiration (9%) rates, and increased water pressure potentials (5%). While all responses were subtle, their cumulative impact over 4 years indicated that 'Valencia' orange trees were subject to increased ambient oxidant stress.

  3. Processing and Oxidation Behavior of Nb-Si-B Intermetallics

    SciTech Connect

    Y.LIU; A.J. Thom; M.J. Kramer; M. Akinc

    2004-09-30

    Single phase materials of {alpha}-Nb{sub 5}Si{sub 3}, Nb{sub 5}(Si,B){sub 3} (T2) and Nb{sub 5}Si{sub 3}B{sub x} (D8{sub 8}) in the Nb-Si-B system were prepared by powder metallurgy processing. T2 was almost fully dense, while {alpha}-Nb{sub 5}Si{sub 3} and D8{sub 8} were porous after sintering at 1900 C for 2 hours. The lattice parameters of T2 decreased linearly with the substitution of B for Si. Isothermal oxidation testing at 1000 C in flowing air indicated that the oxidation resistances of T2 and D8{sub 8} are much better than {alpha}-Nb{sub 5}Si{sub 3}, but still extremely poor compared to the boron-modified Mo{sub 5}Si{sub 3}. Extensive cracking in the oxide scale and matrix were observed and arose from the volume expansion associated with the formation of Nb{sub 2}O{sub 5} and boron-containing silica glass.

  4. Process for fabrication of metal oxide films

    SciTech Connect

    Tracy, C.E.; Benson, D.; Svensson, S.

    1990-07-17

    This invention is comprised of a method of fabricating metal oxide films from a plurality of reactants by inducing a reaction by plasma deposition among the reactants. The plasma reaction is effective for consolidating the reactants and producing thin films of metal oxides, e.g. electro-optically active transition metal oxides, at a high deposition rate. The presence of hydrogen during the plasma reaction enhances the deposition rate of the metal oxide. Various types of metal oxide films can be produced.

  5. [Degradation of beta-naphthol by catalytic wet air oxidation].

    PubMed

    Liu, Jie; Yu, Chao-Ying; Zhao, Pei-Qing; Chen, Ge-Xin

    2012-11-01

    A series of MnO(x)/nano-TiO2 catalysts were prepared and their application in degradation of beta-naphthol by catalytic wet air oxidation (CWAO) was investigated. The catalysts preparation conditions, reaction conditions and its stability were tested. The catalysts had been characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (TPR) measurements. The results showed that the decrease of the COD removal for the degradation of beta-naphthol at high Mn loading was due to the aggregation of the highly dispersed Mn species and the formation of the correlated crystals. The decline of the COD removal at high calcination temperature was probably attributed to the weak electron transfer between Mn2O3 and MnO2 and the formation of the inactive Mn2O3. The COD removal had been falling slightly when the catalyst was used 6 times, and this was likely related to the decrease of the diffraction peaks. The catalyst had a high activity when the Mn loading (mass fraction) was 4% and the calcination temperature was 450 degrees C. The COD removal was up to 96.4% at 110 degrees C and 0.5 MPa with this catalyst. The COD removal of 92.4% could be obtained with the MnO(x)/nano-TiO2 catalyst was recycled 6 times. The Mn leaching at 50, 80, 110 and 150 degrees C were all less than 9.3 mg x L(-1) by means of Atomic Absorption Spectroscopy (AAS). The probable degradation pathway was proposed according to some publications.

  6. Pressurized solid oxide fuel cell integral air accumular containment

    DOEpatents

    Gillett, James E.; Zafred, Paolo R.; Basel, Richard A.

    2004-02-10

    A fuel cell generator apparatus contains at least one fuel cell subassembly module in a module housing, where the housing is surrounded by a pressure vessel such that there is an air accumulator space, where the apparatus is associated with an air compressor of a turbine/generator/air compressor system, where pressurized air from the compressor passes into the space and occupies the space and then flows to the fuel cells in the subassembly module, where the air accumulation space provides an accumulator to control any unreacted fuel gas that might flow from the module.

  7. Oxidation Behavior of Germanium- and/or Silicon-Bearing Near-α Titanium Alloys in Air

    NASA Astrophysics Data System (ADS)

    Kitashima, Tomonori; Yamabe-Mitarai, Yoko

    2015-06-01

    The effect of germanium (Ge) and/or silicon (Si) addition on the oxidation behavior of the near-α alloy Ti-5Al-2Sn-4Zr-2Mo was investigated in air at 973 K (700 °C). Ge addition decreased the oxidation resistance because of the formation of a Ge-rich layer in the substrate at the TiO2/substrate interface, enhancing Sn segregation at the interface. In addition, a small amount of Ge dissolved in the external Al2O3 layer. These results reduced the aluminum activity at the interface, suppressed the formation of Al2O3, and increased the diffusivity of oxygen in the oxide scales. The addition of 0.2 and 0.9 wt pct Si was beneficial for improving oxidation resistance. The effect of germanide and silicide precipitates in the matrix on the oxide growth process was also discussed.

  8. Partial oxidation process with extractant purification

    SciTech Connect

    Stellaccio, R.J.

    1983-09-06

    A partial oxidation process is disclosed with an extractant purifier for removing the particulate carbon entrained in a vaporized stream of normally liquid organic extractant-carbon-water dispersion from a decanter and producing a clean vaporized mixture of liquid organic extractant and water and a separate liquid stream of liquid hydrocarbonaceous fuel-carbon dispersion. The extractant purifier comprises a closed, vertical, cylindrical, thermally insulated vessel with an unobstructed central passage. Supported in the upper section of the vessel is a gas-solids separator for separating the particulate carbon from the vaporized dispersion flowing up the vessel and discharging the particulate carbon into atomized liquid hydrocarbon fuel located within the lower section of the purifier.

  9. Process for selected gas oxide removal by radiofrequency catalysts

    DOEpatents

    Cha, Chang Y.

    1993-01-01

    This process to remove gas oxides from flue gas utilizes adsorption on a char bed subsequently followed by radiofrequency catalysis enhancing such removal through selected reactions. Common gas oxides include SO.sub.2 and NO.sub.x.

  10. Reactive nitrogen oxides in the southeast United States national parks: source identification, origin, and process budget

    NASA Astrophysics Data System (ADS)

    Tong, Daniel Quansong; Kang, Daiwen; Aneja, Viney P.; Ray, John D.

    2005-01-01

    We present in this study both measurement-based and modeling analyses for elucidation of source attribution, influence areas, and process budget of reactive nitrogen oxides at two rural southeast United States sites (Great Smoky Mountains national park (GRSM) and Mammoth Cave national park (MACA)). Availability of nitrogen oxides is considered as the limiting factor to ozone production in these areas and the relative source contribution of reactive nitrogen oxides from point or mobile sources is important in understanding why these areas have high ozone. Using two independent observation-based techniques, multiple linear regression analysis and emission inventory analysis, we demonstrate that point sources contribute a minimum of 23% of total NOy at GRSM and 27% at MACA. The influence areas for these two sites, or origins of nitrogen oxides, are investigated using trajectory-cluster analysis. The result shows that air masses from the West and Southwest sweep over GRSM most frequently, while pollutants transported from the eastern half (i.e., East, Northeast, and Southeast) have limited influence (<10% out of all air masses) on air quality at GRSM. The processes responsible for formation and removal of reactive nitrogen oxides are investigated using a comprehensive 3-D air quality model (Multiscale Air Quality SImulation Platform (MAQSIP)). The NOy contribution associated with chemical transformations to NOz and O3, based on process budget analysis, is as follows: 32% and 84% for NOz, and 26% and 80% for O3 at GRSM and MACA, respectively. The similarity between NOz and O3 process budgets suggests a close association between nitrogen oxides and effective O3 production at these rural locations.

  11. Development studies for a novel wet oxidation process. Phase 2

    SciTech Connect

    1994-07-01

    DETOX{sup SM} is a catalyzed wet oxidation process which destroys organic materials in an acidic water solution of iron at 373 to 473 K. The solution can be used repeatedly to destroy great amounts of organic materials. Since the process is conducted in a contained vessel, air emissions from the process can be well controlled. The solution is also capable of dissolving and concentrating many heavy and radioactive metals for eventual stabilization and disposal. The Phase 2 effort for this project is site selection and engineering design for a DETOX demonstration unit. Site selection was made using a set of site selection criteria and evaluation factors. A survey of mixed wastes at DOE sites was conducted using the Interim Mixed Waste Inventory Report. Sites with likely suitable waste types were identified. Potential demonstration sites were ranked based on waste types, interest, regulatory needs, scheduling, ability to provide support, and available facilities. Engineering design for the demonstration unit is in progress and is being performed by Jacobs Applied Technology. The engineering design proceeded through preliminary process flow diagrams (PFDs), calculation of mass and energy balances for representative waste types, process and instrumentation diagrams (P and IDs), preparation of component specifications, and a firm cost estimate for fabrication of the demonstration unit.

  12. Novel Molten Oxide Membrane for Ultrahigh Purity Oxygen Separation from Air.

    PubMed

    Belousov, Valery V; Kulbakin, Igor V; Fedorov, Sergey V; Klimashin, Anton A

    2016-08-31

    We present a novel solid/liquid Co3O4-36 wt % Bi2O3 composite that can be used as molten oxide membrane, MOM ( Belousov, V. V. Electrical and Mass Transport Processes in Molten Oxide Membranes. Ionics 22 , 2016 , 451 - 469 ), for ultrahigh purity oxygen separation from air. This membrane material consists of Co3O4 solid grains and intergranular liquid channels (mainly molten Bi2O3). The solid grains conduct electrons, and the intergranular liquid channels predominantly conduct oxygen ions. The liquid channels also provide the membrane material gas tightness and ductility. This last property allows us to deal successfully with the problem of thermal incompatibility. Oxygen and nitrogen permeation fluxes, oxygen ion transport number, and conductivity of the composite were measured by the gas flow, volumetric measurements of the faradaic efficiency, and four-probe dc techniques, accordingly. The membrane material showed the highest oxygen selectivity jO2/jN2 > 10(5) and sufficient oxygen permeability 2.5 × 10(-8) mol cm(-1) s(-1) at 850 °C. In the range of membrane thicknesses 1.5-3.3 mm, the oxygen permeation rate was controlled by chemical diffusion. The ease of the MOM fabrication, combined with superior oxygen selectivity and competitive oxygen permeability, shows the promise of the membrane material for ultrahigh purity oxygen separation from air. PMID:27482771

  13. Novel Molten Oxide Membrane for Ultrahigh Purity Oxygen Separation from Air.

    PubMed

    Belousov, Valery V; Kulbakin, Igor V; Fedorov, Sergey V; Klimashin, Anton A

    2016-08-31

    We present a novel solid/liquid Co3O4-36 wt % Bi2O3 composite that can be used as molten oxide membrane, MOM ( Belousov, V. V. Electrical and Mass Transport Processes in Molten Oxide Membranes. Ionics 22 , 2016 , 451 - 469 ), for ultrahigh purity oxygen separation from air. This membrane material consists of Co3O4 solid grains and intergranular liquid channels (mainly molten Bi2O3). The solid grains conduct electrons, and the intergranular liquid channels predominantly conduct oxygen ions. The liquid channels also provide the membrane material gas tightness and ductility. This last property allows us to deal successfully with the problem of thermal incompatibility. Oxygen and nitrogen permeation fluxes, oxygen ion transport number, and conductivity of the composite were measured by the gas flow, volumetric measurements of the faradaic efficiency, and four-probe dc techniques, accordingly. The membrane material showed the highest oxygen selectivity jO2/jN2 > 10(5) and sufficient oxygen permeability 2.5 × 10(-8) mol cm(-1) s(-1) at 850 °C. In the range of membrane thicknesses 1.5-3.3 mm, the oxygen permeation rate was controlled by chemical diffusion. The ease of the MOM fabrication, combined with superior oxygen selectivity and competitive oxygen permeability, shows the promise of the membrane material for ultrahigh purity oxygen separation from air.

  14. PROCESS OF PRODUCING REFRACTORY URANIUM OXIDE ARTICLES

    DOEpatents

    Hamilton, N.E.

    1957-12-01

    A method is presented for fabricating uranium oxide into a shaped refractory article by introducing a uranium halide fluxing reagent into the uranium oxide, and then mixing and compressing the materials into a shaped composite mass. The shaped mass of uranium oxide and uranium halide is then fired at an elevated temperature so as to form a refractory sintered article. It was found in the present invention that the introduction of a uraninm halide fluxing agent afforded a fluxing action with the uranium oxide particles and that excellent cohesion between these oxide particles was obtained. Approximately 90% of uranium dioxide and 10% of uranium tetrafluoride represent a preferred composition.

  15. Effects of oxides of nitrogen on California air quality. Final report

    SciTech Connect

    Not Available

    1986-03-01

    The report was written because of California Air Resources Board concerns about the multiple effects of oxides of nitrogen (NOx) emissions on California air quality. The deleterious effects are expected to increase because NOx emissions are expected to increase in 1990's. The report discusses six major products of nitrogen oxide (NOx) emissions: nitrogen dioxide, ozone, particulate nitrates, acid deposition, visibility impairment, other nitrogen compounds. For each product, the report describes health and welfare effects, atmospheric chemistry by which NOx emissions are transformed into various air pollutants, relevant ambient air quality standards, ambient concentrations measured in California, and status in attaining ambient air standards. Because ozone is California's most severe air pollution problem, the report discusses in depth the relationship of NOx and ozone. In most areas of California, ozone strategies have reduced hydrocarbon emissions while maintaining NOx emissions. Evidence is increasing that reduction of NOx emissions also reduces ozone.

  16. Experimental Air Pressure Tank Systems for Process Control Education

    ERIC Educational Resources Information Center

    Long, Christopher E.; Holland, Charles E.; Gatzke, Edward P.

    2006-01-01

    In process control education, particularly in the field of chemical engineering, there is an inherent need for industrially relevant hands-on apparatuses that enable one to bridge the gap between the theoretical content of coursework and real-world applications. At the University of South Carolina, two experimental air-pressure tank systems have…

  17. Process Heater Ultra-low Excess Air Control

    SciTech Connect

    David V. Thompson

    2006-06-30

    The objective of this project was to demonstrate automatic control of combustion within process heaters using flue gas carbon monoxide (CO) instead of flue gas oxygen (excess air) as the control point for the burner registers to continually achieve near stoichiometric conditions without operator adjustments.

  18. Thick film oxidation of copper in an electroplated MEMS process

    NASA Astrophysics Data System (ADS)

    Lazarus, N.; Meyer, C. D.; Bedair, S. S.; Song, X.; Boteler, L. M.; Kierzewski, I. M.

    2013-06-01

    Copper forms a porous oxide, allowing the formation of oxide layers up to tens of microns thick to be created at modest processing temperatures. In this work, the controlled oxidation of copper is employed within an all-metal electroplating process to create electrically insulating, structural posts and beams. This capability could eliminate the additional dielectric deposition and patterning steps that are often needed during the construction of sensors, waveguides, and other microfabricated devices. In this paper, copper oxidation rates for thermal and plasma-assisted growth methods are characterized. Time control of the oxide growth enables larger copper structures to remain conductive while smaller copper posts are fully oxidized. The concept is demonstrated using the controlled oxidation of a copper layer between two nickel layers to fabricate nickel inductors having both copper electrical vias and copper oxide support pillars. Nickel was utilized in this demonstration for its resistance against low temperature oxidation and interdiffusion with copper.

  19. Air Quality Criteria for Ozone and Related Photochemical Oxidants (Second External Review Draft)

    EPA Science Inventory

    This second external review draft of the Air Quality Criteria for Ozone and Related Photochemical Oxidants, Volumes I-III (Ozone Criteria Document) is being released for public comment and for review by EPA's Clean Air Scientific Advisory Committee (CASAC) r...

  20. Effect of fuel-air-ratio nonuniformity on emissions of nitrogen oxides

    NASA Technical Reports Server (NTRS)

    Lyons, V. J.

    1981-01-01

    The inlet fuel-air ratio nonuniformity is studied to deterine how nitrogen oxide (NOx) emissions are affected. An increase in NOx emissions with increased fuel-air ratio nonuniformity for average equivalence ratios less than 0.7 and a decrease in NOx emissions for average equivalence ratios near stoichiometric is predicted. The degree of uniformityy of fuel-air ratio profiles that is necessary to achieve NOx emissions goals for actual engines that use lean, premixed, prevaporized combustion systems is determined.

  1. Remediation of a winery wastewater combining aerobic biological oxidation and electrochemical advanced oxidation processes.

    PubMed

    Moreira, Francisca C; Boaventura, Rui A R; Brillas, Enric; Vilar, Vítor J P

    2015-05-15

    Apart from a high biodegradable fraction consisting of organic acids, sugars and alcohols, winery wastewaters exhibit a recalcitrant fraction containing high-molecular-weight compounds as polyphenols, tannins and lignins. In this context, a winery wastewater was firstly subjected to a biological oxidation to mineralize the biodegradable fraction and afterwards an electrochemical advanced oxidation process (EAOP) was applied in order to mineralize the refractory molecules or transform them into simpler ones that can be further biodegraded. The biological oxidation led to above 97% removals of dissolved organic carbon (DOC), chemical oxygen demand (COD) and 5-day biochemical oxygen demand (BOD5), but was inefficient on the degradation of a bioresistant fraction corresponding to 130 mg L(-1) of DOC, 380 mg O2 L(-1) of COD and 8.2 mg caffeic acid equivalent L(-1) of total dissolved polyphenols. Various EAOPs such as anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF), UVA photoelectro-Fenton (PEF) and solar PEF (SPEF) were then applied to the recalcitrant effluent fraction using a 2.2 L lab-scale flow plant containing an electrochemical cell equipped with a boron-doped diamond (BDD) anode and a carbon-PTFE air-diffusion cathode and coupled to a photoreactor with compound parabolic collectors (CPCs). The influence of initial Fe(2+) concentration and current density on the PEF process was evaluated. The relative oxidative ability of EAOPs increased in the order AO-H2O2 < EF < PEF ≤ SPEF. The SPEF process using an initial Fe(2+) concentration of 35 mg L(-1), current density of 25 mA cm(-2), pH of 2.8 and 25 °C reached removals of 86% on DOC and 68% on COD after 240 min, regarding the biologically treated effluent, along with energy consumptions of 45 kWh (kg DOC)(-1) and 5.1 kWh m(-3). After this coupled treatment, color, odor, COD, BOD5, NH4(+), NO3(-) and SO4(2-) parameters complied with the legislation targets and, in addition, a total

  2. Remediation of a winery wastewater combining aerobic biological oxidation and electrochemical advanced oxidation processes.

    PubMed

    Moreira, Francisca C; Boaventura, Rui A R; Brillas, Enric; Vilar, Vítor J P

    2015-05-15

    Apart from a high biodegradable fraction consisting of organic acids, sugars and alcohols, winery wastewaters exhibit a recalcitrant fraction containing high-molecular-weight compounds as polyphenols, tannins and lignins. In this context, a winery wastewater was firstly subjected to a biological oxidation to mineralize the biodegradable fraction and afterwards an electrochemical advanced oxidation process (EAOP) was applied in order to mineralize the refractory molecules or transform them into simpler ones that can be further biodegraded. The biological oxidation led to above 97% removals of dissolved organic carbon (DOC), chemical oxygen demand (COD) and 5-day biochemical oxygen demand (BOD5), but was inefficient on the degradation of a bioresistant fraction corresponding to 130 mg L(-1) of DOC, 380 mg O2 L(-1) of COD and 8.2 mg caffeic acid equivalent L(-1) of total dissolved polyphenols. Various EAOPs such as anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF), UVA photoelectro-Fenton (PEF) and solar PEF (SPEF) were then applied to the recalcitrant effluent fraction using a 2.2 L lab-scale flow plant containing an electrochemical cell equipped with a boron-doped diamond (BDD) anode and a carbon-PTFE air-diffusion cathode and coupled to a photoreactor with compound parabolic collectors (CPCs). The influence of initial Fe(2+) concentration and current density on the PEF process was evaluated. The relative oxidative ability of EAOPs increased in the order AO-H2O2 < EF < PEF ≤ SPEF. The SPEF process using an initial Fe(2+) concentration of 35 mg L(-1), current density of 25 mA cm(-2), pH of 2.8 and 25 °C reached removals of 86% on DOC and 68% on COD after 240 min, regarding the biologically treated effluent, along with energy consumptions of 45 kWh (kg DOC)(-1) and 5.1 kWh m(-3). After this coupled treatment, color, odor, COD, BOD5, NH4(+), NO3(-) and SO4(2-) parameters complied with the legislation targets and, in addition, a total

  3. CONCENTRATED AMBIENT AIR POLLUTION CREATES OXIDATIVE STRESS IN CNS MICROGLIA.

    EPA Science Inventory

    Nanometer size particles carry free radical activity on their surface and can produce oxidative stress (OS)-mediated damage upon impact to target cells. The initiating event of phage cell activation (i.e., the oxidative burst) is unknown, although many proximal events have been i...

  4. Air stripping VOCs from groundwater: Process design considerations

    SciTech Connect

    Ball, B.R.; Edwards, M.D. )

    1992-02-01

    Considerations for evaluating and designing the air stripping process are presented by case study. The case study involves the design of an air stripping process to remediate groundwater contaminated with volatile organic compounds (VOCs) at a National Priorities List site in Tacoma, WA. Design objectives included developing a tower with minimum volume and energy requirements while complying with discharge air and water quality standards. A two-phase resistance model using Onda Correlations to determine liquid- and gas-phase mass transfer coefficients was used to assist in the evaluation and design. Considerations for applying the two-phase resistance model to air stripping tower design are presented. The ability of the model to simulate process performance is demonstrated by comparison with actual data for 11 priority pollutant list VOCs evaluated during an onsite pilot study. Design procedures with which to develop a tower with minimum volume and energy requirements are described. Other considerations involving the evaluation of VOC emissions and the precipitation and buildup of inorganic constituents within the internal packing media are described.

  5. Generation and annihilation of traps in metal-oxide-semiconductor devices after negative air corona charging

    NASA Astrophysics Data System (ADS)

    Prasad, Ila; Srivastava, R. S.

    1993-07-01

    Surface and bulk traps along with positive oxide charge accumulation have been found to be generated in metal-oxide-semiconductor capacitors, when subjected to negative air corona discharge at slightly reduced pressure (≂10-1 Torr). The effects are neutralized and device quality improved when annealed at 200 °C in air. The bulk traps and a fraction of oxide charges were annealable when kept at room temperature for several months. The results have been analyzed by Nicollian-Goetzberger's conductance technique and a plausible explanation is given.

  6. Development of a Catalytic Wet Air Oxidation Method to Produce Feedstock Gases from Waste Polymers

    NASA Technical Reports Server (NTRS)

    Kulis, Michael J.; Guerrero-Medina, Karen J.; Hepp, Aloysius F.

    2012-01-01

    Given the high cost of space launch, the repurposing of biological and plastic wastes to reduce the need for logistical support during long distance and long duration space missions has long been recognized as a high priority. Described in this paper are the preliminary efforts to develop a wet air oxidation system in order to produce fuels from waste polymers. Preliminary results of partial oxidation in near supercritical water conditions are presented. Inherent corrosion and salt precipitation are discussed as system design issues for a thorough assessment of a second generation wet air oxidation system. This work is currently being supported by the In-Situ Resource Utilization Project.

  7. Oxidation Ditches. Student Manual. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Nelsen, David

    The textual material for a two-lesson unit on oxidation ditches is presented in this student manual. Topics discussed in the first lesson (introduction, theory, and components) include: history of the oxidation ditch process; various designs of the oxidation ditch; multi-trench systems; carrousel system; advantages and disadvantages of the…

  8. Heterogeneous photocatalytic effect of zinc oxide on photochemical smog formation reaction of C 4H 8-NO 2-air

    NASA Astrophysics Data System (ADS)

    Takeuchi, Koji; Yazawa, Takenori; Ibusuki, Takashi

    As a model of heterogeneous photochemical smog formation reaction, butene-NO 2-air systems in the presence of zinc oxide were experimentally studied using a flowing reaction system. Zinc oxide revealed a remarkable photocatalytic action which involved the production of hitherto unreported species such as cyano-compounds (HCN and CH 3CN) as well as a striking change in the distribution of the reaction products (aldehydes, ketones, epoxides, alkyl nitrates, HNO 3, CO, CO 2, etc.). It is confirmed that ZnO little affected the initial process of gas-phase photochemical reactions but interacted photocatalytically with the gas-phase reaction products.

  9. 77 FR 63827 - Request for Nominations of Experts for the Clean Air Scientific Advisory Committee (CASAC) Oxides...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-17

    ... of Nitrogen Primary National Ambient Air Quality Standards (NAAQS) Review Panel AGENCY: Environmental... the chartered CASAC on primary (human health-based) air quality standards for oxides of nitrogen (NO X... six ``criteria'' air pollutants, including oxides of nitrogen. As a Federal Advisory Committee,...

  10. Homogeneous catalytic wet-air oxidation for the treatment of textile wastewater

    SciTech Connect

    Lei, L. Chen, G.; Hu, X.; Yue, P.L.

    2000-04-01

    An extensive series of experiments was performed to identify suitable catalysts to increase the reaction rate of wet-air oxidation of textile wastewater t relatively mild temperatures an pressures. Wastewater types treated included natural-fiber desizing wastewater, synthetic-fiber desizing wastewater, and printing and dyeing wastewater. Experimental results indicated that all catalysts tested in this investigation significantly increased the chemical oxygen demand (COD) and total organic carbon (TOC) removal rates and total COD and TOC removals. Of all catalysts tested, copper salts were the most effective. Anions in the slat solutions played a role in the catalytic process. Nitrate ions were more effective than sulfate ions. Similarly, copper nitrates were more effective than copper sulfates. A mixture of salts containing different metals performed better than any single salt.

  11. 40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section... quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). (a) The level of the national primary annual ambient air quality standard for oxides of nitrogen is 53 parts per billion...

  12. 40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section... quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). (a) The level of the national primary annual ambient air quality standard for oxides of nitrogen is 53 parts per billion...

  13. 40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section... quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). (a) The level of the national primary annual ambient air quality standard for oxides of nitrogen is 53 parts per billion...

  14. 40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section... quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). (a) The level of the national primary annual ambient air quality standard for oxides of nitrogen is 53 parts per billion...

  15. 40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section... quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). (a) The level of the national primary annual ambient air quality standard for oxides of nitrogen is 53 parts per billion...

  16. Quantitative Analysis of Major Phytochemicals in Orthodox tea (Camellia sinensis), Oxidized under Compressed Air Environment.

    PubMed

    Panda, Brajesh Kumar; Datta, Ashis Kumar

    2016-04-01

    This study describes major changes in phytochemical composition of orthodox tea (Camellia sinensis var. Assamica) oxidized under compressed air (CA). The experiments for oxidation were conducted under air pressure (101, 202, and 303 kPa) for 150 min. Relative change in the concentrations of caffeine, catechins, theaflavins (TF), and thearubigins (TR) were analyzed. Effect of CA pressure was found to be nonsignificant in regulating caffeine concentration during oxidation. But degradation in different catechins as well as formation of different TF was significantly affected by CA pressure. At high CA pressure, TF showed highest peak value. TR was found to have slower rate of formation during initial phase of oxidation than TF. Even though the rate of TR formation was significantly influenced by CA, a portion of catechins remained unoxidized at end of oxidation. Except caffeine, the percent change in rate of formation or degradation were more prominent at 202 kPa.

  17. Air Oxidation of Activated Carbon to Synthesize a Biomimetic Catalyst for Hydrolysis of Cellulose.

    PubMed

    Shrotri, Abhijit; Kobayashi, Hirokazu; Fukuoka, Atsushi

    2016-06-01

    Oxygenated carbon catalyzes the hydrolysis of cellulose present in lignocellulosic biomass by utilizing the weakly acidic functional groups on its surface. Here we report the synthesis of a biomimetic carbon catalyst by simple and economical air-oxidation of a commercially available activated carbon. Air- oxidation at 450-500 °C introduced 2000-2400 μmol g(-1) of oxygenated functional groups on the material with minor changes in the textural properties. Selectivity towards the formation of carboxylic groups on the catalyst surface increased with the increase in oxidation temperature. The degree of oxidation on carbon catalyst was found to be proportional to its activity for hydrolysis of cellulose. The hydrolysis of eucalyptus in the presence of carbon oxidized at 475 °C afforded glucose yield of 77 % and xylose yield of 67 %.

  18. Oxidation Behaviors of Inconel 740H in Air and Dynamic Steam

    NASA Astrophysics Data System (ADS)

    Lu, Jintao; Yang, Zhen; Xu, Songqian; Zhao, Haiping; Gu, Y.

    2016-08-01

    Inconel 740H alloy is a candidate material for 700°C advanced ultra-supercritical (A-USC) coal-fired power plants application as superheater/reheater tube. In this work, oxidation behavior of Inconel 740H alloy was studied in static air at 750°C and 850°C, and in dynamic pure steam at 750°C, respectively. The alloy was oxidized approximately following a parabolic law in three test environment. In the static air, the oxidation rate at 850°C was about 50 times of that at the 750°C. More NiCrMn spinal and TiO2 were detected after oxidation at 850°C. Cr2O3, however, was the main oxidation product at 750°C. In the pure steam, Cr2O3 was still the main oxidation product. The oxidation rate was about 2.6 times of that in static air, but the surface roughness was much smaller and edges of oxide particles were more blurred. There was no evidence of cracks or spallation in three test environments.

  19. Synthesis and processing of monosized oxide powders

    DOEpatents

    Barringer, E.A.; Fegley, M.B. Jr.; Bowen, H.K.

    1985-09-24

    Uniform-size, high-purity, spherical oxide powders are formed by hydrolysis of alkoxide precursors in dilute alcoholic solutions. Under controlled conditions (concentrations of 0.03 to 0.2 M alkoxide and 0.2 to 1.5 M water, for example) oxide particles on the order of about 0.05 to 0.7 microns can be produced. Methods of doping such powders and forming sinterable compacts are also disclosed. 6 figs.

  20. Synthesis and processing of monosized oxide powders

    DOEpatents

    Barringer, Eric A.; Fegley, Jr., M. Bruce; Bowen, H. Kent

    1985-01-01

    Uniform-size, high-purity, spherical oxide powders are formed by hydrolysis of alkoxide precursors in dilute alcoholic solutions. Under controlled conditions (concentrations of 0.03 to 0.2 M alkoxide and 0.2 to 1.5 M water, for example) oxide particles on the order of about 0.05 to 0.7 micron can be produced. Methods of doping such powders and forming sinterable compacts are also disclosed.

  1. Investigating the air oxidation of V(II) ions in a vanadium redox flow battery

    NASA Astrophysics Data System (ADS)

    Ngamsai, Kittima; Arpornwichanop, Amornchai

    2015-11-01

    The air oxidation of vanadium (V(II)) ions in a negative electrolyte reservoir is a major side reaction in a vanadium redox flow battery (VRB), which leads to electrolyte imbalance and self-discharge of the system during long-term operation. In this study, an 80% charged negative electrolyte solution is employed to investigate the mechanism and influential factors of the reaction in a negative-electrolyte reservoir. The results show that the air oxidation of V(II) ions occurs at the air-electrolyte solution interface area and leads to a concentration gradient of vanadium ions in the electrolyte solution and to the diffusion of V(II) and V(III) ions. The effect of the ratio of the electrolyte volume to the air-electrolyte solution interface area and the concentrations of vanadium and sulfuric acid in an electrolyte solution is investigated. A higher ratio of electrolyte volume to the air-electrolyte solution interface area results in a slower oxidation reaction rate. The high concentrations of vanadium and sulfuric acid solution also retard the air oxidation of V(II) ions. This information can be utilized to design an appropriate electrolyte reservoir for the VRB system and to prepare suitable ingredients for the electrolyte solution.

  2. Processing and mechanical behavior of Nicalon{reg_sign}/SiC composites with sol-gel derived oxide interfacial coatings

    SciTech Connect

    Shanmugham, S.; Liaw, P.K.

    1996-10-01

    Recent analytical and finite element modeling studies have indicated that low modulus interface materials are desirable for obtaining Nicalon/SiC composites with good toughness. Two oxides, Al titanate and mullite, were chosen on this basis as interface materials. The oxide and C coatings were deposited by sol-gel and CVD, respectively. Nicalon/SiC composites with oxide/C and C/oxide/C interfaces were fabricated and evaluated for flexure strength in the as-processed and oxidized conditions. Composites with C/oxide/C interfaces retained considerable strength and damage-tolerant behavior even after 500 h oxidation at 1000 C in air. The C/oxide/C interface shows promise as a viable oxidation-resistant interface alternative to C or BN interfaces.

  3. Nitrogen oxide removal dynamic process through 15 Ns DBD technique

    NASA Astrophysics Data System (ADS)

    Wang, Xiaojun; Zhang, Lianshui; Lai, Weidong; Liu, Fengliang

    2015-05-01

    Nitrogen oxides exhaust gas assumes the important responsibility on air pollution by forming acid rain. This paper discusses the NO removal mechanism in 15 ns pulse dielectric barrier discharge (DBD) plasma through experimental and simulating method. Emission spectra collected from plasma are evaluated as sourced from N+ and O(3P). The corresponding zero-dimensional model is established and verified through comparing the simulated concentration evolution and the experimental time-resolved spectra of N+. The electron impact ionization plays major role on NO removal and the produced NO+ are further decomposed into N+ and O(3P) through electron impact dissociative excitation rather than the usual reported dissociative recombination process. Simulation also indicates that the removal process can be accelerated by NO inputted at lower initial concentration or electrons streamed at higher concentration, due to the heightened electron impact probability on NO molecules. The repetitive pulse discharge is a benefit for improving the NO removal efficiency by effectively utilizing the radicals generated from the previous pulse under the condition that the pulse period should be shorter enough to ignore the spatial diffusion of radicals. Finally, slight attenuation on NO removal has been experimentally and simulatively observed after N2 mixed, due to the competitive consumption of electrons.

  4. Process for the separation of sulfur oxides from a gaseous mixture containing sulfur oxides and oxygen

    SciTech Connect

    Derosset, A.J.; Ginger, E.A.

    1980-12-23

    An improved process for the separation of sulfur oxides from a gaseous mixture containing sulfur oxides and oxygen is disclosed. The gaseous mixture is contacted with a solid sulfur oxide acceptor comprising copper, copper oxide, or a mixture thereof dispersed on a carrier material in combination with a platinum group metal component and a component selected from the group consisting of rhenium, germanium and tin.

  5. Crossflow air stripping with catalytic oxidation. Final report, 1 October 1990-30 September 1994

    SciTech Connect

    Kim, B.C.; Gavaskar, A.R.; Ong, S.K.; Rosansky, S.H.; Cummings, C.A.

    1994-09-30

    A novel air stripping technique was tested on a pilot scale at Dover Air Force Base. Groundwater contaminated with 1,2-dichloroethane was subjected to air stripping in two towers: the novel crossflow tower and the conventional countercurrent tower. The crossflow tower was found to require higher airflow rates but much lower pressure drops to effect the same removal efficiency. The airstream from the towers was directed into bench-scale and pilot-scale commercial catalytic units. An innovative photocatalytic unit also was tested. Five of the six catalysts tested performed well. Air stripping in conjunction with catalytic oxidation was found to be a good technique for remediation of groundwater containing low levels of organics. However the crossflow air stripper did not offer any cost advantages over conventional counterflow air stripping.

  6. The fragrance chemical beta-caryophyllene-air oxidation and skin sensitization.

    PubMed

    Sköld, Maria; Karlberg, Ann-Therese; Matura, Mihaly; Börje, Anna

    2006-04-01

    Fragrances are common causes of allergic contact dermatitis. beta-Caryophyllene is a sesquiterpene that is used as a fragrance chemical. Analogous to the monoterpenes R-limonene and linalool, it can be expected to autoxidize when air exposed. The aim of the present study was to investigate the autoxidation of beta-caryophyllene and to evaluate the effect on the contact allergenic activity. beta-Caryophyllene started to oxidize immediately when air exposed and after 5 weeks almost 50% of the original compound was consumed. Caryophyllene oxide was found to be the major oxidation product. Hydroperoxides of beta-caryophyllene could not be detected in the oxidation mixture. Caryophyllene oxide was shown to be an allergen of moderate strength and beta-caryophyllene air exposed for 10 weeks showed a weak sensitizing capacity in the local lymph node assay. The study reveals that the allergenic activity of beta-caryophyllene is affected by autoxidation, but to a lesser extent when compared to R-limonene and linalool. The present findings support our results in clinical studies showing oxidized beta-caryophyllene to be a rather rare sensitizer compared to oxidized R-limonene and linalool.

  7. Continuous measurements of ammonia, nitrous oxide and methane from air scrubbers at pig housing facilities.

    PubMed

    Van der Heyden, C; Brusselman, E; Volcke, E I P; Demeyer, P

    2016-10-01

    Ammonia, largely emitted by agriculture, involves a great risk for eutrophication and acidification leading to biodiversity loss. Air scrubbers are widely applied to reduce ammonia emission from pig and poultry housing facilities, but it is not always clear whether their performance meets the requirements. Besides, there is a growing international concern for the livestock related greenhouse gases methane and nitrous oxide but hardly any data concerning their fate in air scrubbers are available. This contribution presents the results from measurement campaigns conducted at a chemical, a biological and a two-stage biological air scrubber installed at pig housing facilities in Flanders. Ammonia, nitrous oxide and methane at the inlet and outlet of the air scrubbers were monitored on-line during one week using a photoacoustic gas monitor, which allowed to investigate diurnal fluctuations in the removal performance of air scrubbers. Additionally, the homogeneity of the air scrubbers, normally checked by gas detection tubes, was investigated in more detail using the continuous data. The biological air scrubber with extra nitrification tank performed well in terms of ammonia removal (86 ± 6%), while the two-stage air scrubber suffered from nitrifying bacteria inhibition. In the chemical air scrubber the pH was not kept constant, lowering the ammonia removal efficiency. A lower ammonia removal efficiency was found during the day, when the ventilation rate was the highest. Nitrous oxide was produced inside the biological and two-stage scrubber, resulting in an increased outlet concentration of more than 200%. Methane could not be removed in the different air scrubbers because of its low water solubility. PMID:27341376

  8. Continuous measurements of ammonia, nitrous oxide and methane from air scrubbers at pig housing facilities.

    PubMed

    Van der Heyden, C; Brusselman, E; Volcke, E I P; Demeyer, P

    2016-10-01

    Ammonia, largely emitted by agriculture, involves a great risk for eutrophication and acidification leading to biodiversity loss. Air scrubbers are widely applied to reduce ammonia emission from pig and poultry housing facilities, but it is not always clear whether their performance meets the requirements. Besides, there is a growing international concern for the livestock related greenhouse gases methane and nitrous oxide but hardly any data concerning their fate in air scrubbers are available. This contribution presents the results from measurement campaigns conducted at a chemical, a biological and a two-stage biological air scrubber installed at pig housing facilities in Flanders. Ammonia, nitrous oxide and methane at the inlet and outlet of the air scrubbers were monitored on-line during one week using a photoacoustic gas monitor, which allowed to investigate diurnal fluctuations in the removal performance of air scrubbers. Additionally, the homogeneity of the air scrubbers, normally checked by gas detection tubes, was investigated in more detail using the continuous data. The biological air scrubber with extra nitrification tank performed well in terms of ammonia removal (86 ± 6%), while the two-stage air scrubber suffered from nitrifying bacteria inhibition. In the chemical air scrubber the pH was not kept constant, lowering the ammonia removal efficiency. A lower ammonia removal efficiency was found during the day, when the ventilation rate was the highest. Nitrous oxide was produced inside the biological and two-stage scrubber, resulting in an increased outlet concentration of more than 200%. Methane could not be removed in the different air scrubbers because of its low water solubility.

  9. Supporting the Future Air Traffic Control Projection Process

    NASA Technical Reports Server (NTRS)

    Davison, Hayley J.; Hansman, R. John, Jr.

    2002-01-01

    In air traffic control, projecting what the air traffic situation will be over the next 30 seconds to 30 minutes is a key process in identifying conflicts that may arise so that evasive action can be taken upon discovery of these conflicts. A series of field visits in the Boston and New York terminal radar approach control (TRACON) facilities and in the oceanic air traffic control facilities in New York and Reykjavik, Iceland were conducted to investigate the projection process in two different ATC domains. The results from the site visits suggest that two types of projection are currently used in ATC tasks, depending on the type of separation minima and/or traffic restriction and information display used by the controller. As technologies improve and procedures change, care should be taken by designers to support projection through displays, automation, and procedures. It is critical to prevent time/space mismatches between interfaces and restrictions. Existing structure in traffic dynamics could be utilized to provide controllers with useful behavioral models on which to build projections. Subtle structure that the controllers are unable to internalize could be incorporated into an ATC projection aid.

  10. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  11. Porosity control in nanoporous carbide-derived carbon by oxidation in air and carbon dioxide

    SciTech Connect

    Osswald, S.; Portet, C.; Gogotsi, Y.; Laudisio, G.; Singer, J.P.; Fischer, J.E.; Sokolov, V.V.; Kukushkina, J.A.; Kravchik, A.E.

    2009-07-15

    Carbide-derived carbons (CDC) allow a precise control over the pore size through the selection of the carbide precursor and varying of the synthesis conditions. However, their pore volume is limited by the carbide stoichiometry. While activation of carbons derived from various organic precursors has been widely studied, this process may similarly be able to increase the pore volume and specific surface area of CDC. Oxidation of carbide-derived carbon in air and CO{sub 2} at different temperatures and times allows for significant increase in pore volume and specific surface area as well as control over average pore size with subnanometer accuracy. The effect of activation and associated changes in the pore volume and surface area on the hydrogen uptake are also discussed. - Graphical abstract: Carbide-derived carbons (CDC) provide great potential for sorption of toxicants and gas storage applications. Activation of CDC in air and CO{sub 2} at different temperatures and times is applied in order to maximize pore volume and specific surface area, and control the average pore size with subnanometer accuracy.

  12. Effects of air flow directions on composting process temperature profile

    SciTech Connect

    Kulcu, Recep; Yaldiz, Osman

    2008-07-01

    In this study, chicken manure mixed with carnation wastes was composted by using three different air flow directions: R1-sucking (downward), R2-blowing (upward) and R3-mixed. The aim was to find out the most appropriate air flow direction type for composting to provide more homogenous temperature distribution in the reactors. The efficiency of each aeration method was evaluated by monitoring the evolution of parameters such as temperature, moisture content, CO{sub 2} and O{sub 2} ratio in the material and dry material losses. Aeration of the reactors was managed by radial fans. The results showed that R3 resulted in a more homogenous temperature distribution and high dry material loss throughout the composting process. The most heterogeneous temperature distribution and the lowest dry material loss were obtained in R2.

  13. Generation of low-temperature air plasma for food processing

    NASA Astrophysics Data System (ADS)

    Stepanova, Olga; Demidova, Maria; Astafiev, Alexander; Pinchuk, Mikhail; Balkir, Pinar; Turantas, Fulya

    2015-11-01

    The project is aimed at developing a physical and technical foundation of generating plasma with low gas temperature at atmospheric pressure for food industry needs. As known, plasma has an antimicrobial effect on the numerous types of microorganisms, including those that cause food spoilage. In this work an original experimental setup has been developed for the treatment of different foods. It is based on initiating corona or dielectric-barrier discharge in a chamber filled with ambient air in combination with a certain helium admixture. The experimental setup provides various conditions of discharge generation (including discharge gap geometry, supply voltage, velocity of gas flow, content of helium admixture in air and working pressure) and allows for the measurement of the electrical discharge parameters. Some recommendations on choosing optimal conditions of discharge generation for experiments on plasma food processing are developed.

  14. New approach to the air oxidation of alkenes employing metal nitro complexes as catalysts

    SciTech Connect

    Andrews, M.A.; Chang, T.C.T.; Cheng, C.W.F.; Kelley, K.P.

    1984-01-01

    Alkenes are stoichiometrically and, in the presence of air, catalytically oxidized by cis-bis(aceto-nitrile) chloronitropalladium(II). Oxidation of monosubstituted terminal alkenes and trans-cyclooctene yields the corresponding ketone, oxidation of cyclopentene and cyclohexene the corresponding allyl alcohol, and oxidation of bicyclic alkenes the corresponding epoxide, each with good selectivity for the respective product. Other alkenes give varying mixtures of the above products together with, in some cases, the ..cap alpha..,..beta..-unsaturated ketone. Vinyl ethers yield the corresponding ester while (trimethylsily)ethylene yields (trimethylsilyl)acetaldehyde. The selectivities are rationalized on the basis of ease of ..beta..-hydrogen elimination in observed intermediate heterometallacyclopentane complexes formed by nucleophilic attack of the nitro oxygen atom on the coordinated alkene in alkene nitro complexes. The general role of metallacycles in metal-mediated alkene oxidations and the advantages and disadvantages of intra-vs. intermolecular metal nitro catalyzed alkene oxidations are discussed. 50 references, 4 figures, 3 tables.

  15. Oxidation of artificial sweetener sucralose by advanced oxidation processes: a review.

    PubMed

    Sharma, Virender K; Oturan, Mehmet; Kim, Hyunook

    2014-01-01

    Sucralose, a chlorinated carbohydrate, has shown its increased use as an artificial sweetener and persistently exists in wastewater treatment plant effluents and aquatic environment. This paper aims to review possible degradation of sucralose and related carbohydrates by biological, electrochemical, chemical, and advanced oxidation processes. Biodegradation of sucralose in waterworks did not occur significantly. Electrochemical oxidation of carbohydrates may be applied to seek degradation of sucralose. The kinetics of the oxidation of sucralose and the related carbohydrates by different oxidative species is compared. Free chlorine, ozone, and ferrate did not show any potential to degrade sucralose in water. Advanced oxidation processes, generating highly strong oxidizing agent hydroxyl radicals ((•)OH), have demonstrated effectiveness in transforming sucralose in water. The mechanism of oxidation of sucralose by (•)OH is briefly discussed. PMID:24687789

  16. Oxidation of artificial sweetener sucralose by advanced oxidation processes: a review.

    PubMed

    Sharma, Virender K; Oturan, Mehmet; Kim, Hyunook

    2014-01-01

    Sucralose, a chlorinated carbohydrate, has shown its increased use as an artificial sweetener and persistently exists in wastewater treatment plant effluents and aquatic environment. This paper aims to review possible degradation of sucralose and related carbohydrates by biological, electrochemical, chemical, and advanced oxidation processes. Biodegradation of sucralose in waterworks did not occur significantly. Electrochemical oxidation of carbohydrates may be applied to seek degradation of sucralose. The kinetics of the oxidation of sucralose and the related carbohydrates by different oxidative species is compared. Free chlorine, ozone, and ferrate did not show any potential to degrade sucralose in water. Advanced oxidation processes, generating highly strong oxidizing agent hydroxyl radicals ((•)OH), have demonstrated effectiveness in transforming sucralose in water. The mechanism of oxidation of sucralose by (•)OH is briefly discussed.

  17. Oxidative stress and inflammation generated DNA damage by exposure to air pollution particles.

    PubMed

    Møller, Peter; Danielsen, Pernille Høgh; Karottki, Dorina Gabriela; Jantzen, Kim; Roursgaard, Martin; Klingberg, Henrik; Jensen, Ditte Marie; Christophersen, Daniel Vest; Hemmingsen, Jette Gjerke; Cao, Yi; Loft, Steffen

    2014-01-01

    Generation of oxidatively damaged DNA by particulate matter (PM) is hypothesized to occur via production of reactive oxygen species (ROS) and inflammation. We investigated this hypothesis by comparing ROS production, inflammation and oxidatively damaged DNA in different experimental systems investigating air pollution particles. There is substantial evidence indicating that exposure to air pollution particles was associated with elevated levels of oxidatively damaged nucleobases in circulating blood cells and urine from humans, which is supported by observations of elevated levels of genotoxicity in cultured cells exposed to similar PM. Inflammation is most pronounced in cultured cells and animal models, whereas an elevated level of oxidatively damaged DNA is more pronounced than inflammation in humans. There is non-congruent data showing corresponding variability in effect related to PM sampled at different locations (spatial variability), times (temporal variability) or particle size fraction across different experimental systems of acellular conditions, cultured cells, animals and humans. Nevertheless, there is substantial variation in the genotoxic, inflammation and oxidative stress potential of PM sampled at different locations or times. Small air pollution particles did not appear more hazardous than larger particles, which is consistent with the notion that constituents such as metals and organic compounds also are important determinants for PM-generated oxidative stress and inflammation. In addition, the results indicate that PM-mediated ROS production is involved in the generation of inflammation and activated inflammatory cells can increase their ROS production. The observations indicate that air pollution particles generate oxidatively damaged DNA by promoting a milieu of oxidative stress and inflammation.

  18. Process study and exergy analysis of a novel air separation process cooled by LNG cold energy

    NASA Astrophysics Data System (ADS)

    Xu, Wendong; Duan, Jiao; Mao, Wenjun

    2014-02-01

    In order to resolve the problems of the current air separation process such as the complex process, cumbersome operation and high operating costs, a novel air separation process cooled by LNG cold energy is proposed in this paper, which is based on high-efficiency heat exchanger network and chemical packing separation technology. The operating temperature range of LNG cold energy is widened from 133K-203K to 113K-283K by high-efficiency heat exchanger network and air separation pressure is declined from 0.5MPa to about 0.35MPa due to packing separation technology, thereby greatly improve the energy efficiency. Both the traditional and novel air separation processes are simulated with air handling capacity of 20t·h-1. Comparing with the traditional process, the LNG consumption is reduced by 44.2%, power consumption decrease is 211.5 kWh per hour, which means the annual benefit will be up to 1.218 million CNY. And the exergy efficiency is also improved by 42.5%.

  19. Elemental Metals or Oxides Distributed on a Carbon Substrate or Self-Supported and the Manufacturing Process Using Graphite Oxide as Template

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh (Inventor)

    1999-01-01

    A process for providing elemental metals or metal oxides distributed on a carbon substrate or self-supported utilizing graphite oxide as a precursor. The graphite oxide is exposed to one or more metal chlorides to form an intermediary product comprising carbon, metal, chloride, and oxygen. This intermediary product can be further processed by direct exposure to carbonate-solutions to form a second intermediary product comprising carbon, metal carbonate, and oxygen. Either intermediary product may be further processed: a) in air to produce metal oxide; b) in an inert environment to produce metal oxide on carbon substrate; c) in a reducing environment to produce elemental metal distributed on carbon substrate. The product generally takes the shape of the carbon precursor.

  20. The role of oxidation in the fretting wear process

    NASA Technical Reports Server (NTRS)

    Bill, R. C.

    1980-01-01

    Fretting experiments were conducted on titanium, a series of Ni-Cr-Al alloys and on some high temperature turbine alloys at room temperature and at elevated temperatures in air and in various inert environments. It was found that, depending on temperature and environment, the fretting behavior of the materials examined could be classified according to four general types of behavior. Briefly, these types of behavior were: (1) the complete absence of oxidation, as in inert environments, generally leading to low rates of fretting wear but high fretting friction; (2) gradual attrition of surface oxide with each fretting stroke, found in these experiments to operate in concert with other dominating mechanisms; (3) rapid oxidation at surface fatigue damage sites, resulting in undermining and rapid disintegration of the load bearing surface; and (4) the formation of coherent, protective oxide film, resulting in low rates of fretting wear. An analytical model predicting conditions favorable to the fourth type of behavior was outlined.

  1. Corrosion study in the chemical air separation (MOLTOX trademark ) process

    SciTech Connect

    Kang, Doohee; Wong, Kai P.; Archer, R.A.; Cassano, A.A.

    1988-12-01

    This report presents the results of studies aimed at solving the corrosion problems encountered during operation of the MOLTOX{trademark} pilot plant. These studies concentrated on the screening of commercial and developmental alloys under conditions simulating operation conditions in this high temperature molten salt process. Process economic studies were preformed in parallel with the laboratory testing to ensure that an economically feasible solution would be achieved. In addition to the above DOE co-funded studies, Air Products and Chemicals pursued proprietary studies aimed at developing a less corrosive salt mixture which would potentially allow the use of chemurgically available alloys such as stainless steels throughout the system. These studies will not be reported here; however, the results of corrosion tests in the new less corrosive salt mixtures are reported. Because our own studies on salt chemistry impacts heavily on the overall process and thereby has an influence on the experimental work conducted under this contract, some of the studies discussed here were impacted by our own proprietary data. Therefore, the reasons behind some of the experiments presented herein will not be explained because that information is proprietary to Air Products. 14 refs., 42 figs., 21 tabs.

  2. Effects of ambient oxidant air pollution in the San Joaquin Valley on Thompson seedless grapes

    SciTech Connect

    Brewer, R.F.; Ashcroft, R.

    1984-01-01

    Mature Thompson seedless grape vines were enclosed in specially constructed plastic covered chambers supplied with carbon filtered and non-filtered (ambient) air from time of bud break through leaf drop. Effects on vegetative growth and fruiting were determined for three seasons. No effects on fruit production were measured the first season after covering but vegetative growth increased 12% in chambers supplied with filtered air. By the third season fruit yields were 27.5% higher in the filtered as compared with ambient chambers. The only visible symptoms associated with exposure to the oxidants was accelerated senescence which appeared 3 weeks to 1 month earlier on vines receiving ambient or nonfiltered air.

  3. Fabrication and characterization of oxide-based thin film transistors, and process development for oxide heterostructures

    NASA Astrophysics Data System (ADS)

    Lim, Wantae

    2009-12-01

    This dissertation is focused on the development of thin film transistors (TFTs) using oxide materials composed of post-transitional cations with (n-1)d 10ns0 (n≥4). The goal is to achieve high performance oxide-based TFTs fabricated at low processing temperature on either glass or flexible substrates for next generation display applications. In addition, etching mechanism and Ohmic contact formation for oxide heterostructure (ZnO/CuCrO 2) system is demonstrated. The deposition and characterization of oxide semiconductors (In 2O3-ZnO, and InGaZnO4) using a RF-magnetron sputtering system are studied. The main influence on the resistivity of the films is found to be the oxygen partial pressure in the sputtering ambient. The films remained amorphous and transparent (> 70%) at all process conditions. These films showed good transmittance at suitable conductivity for transistor fabrication. The electrical characteristics of both top- and bottom-gate type Indium Zinc Oxide (InZnO) and Indium Gallium Zinc Oxide (InGaZnO4)-based TFTs are reported. The InZnO films were favorable for depletion-mode TFTs due to their tendency to form oxygen vacancies, while enhancement-mode devices were realized with InGaZnO4 films. The InGaZnO4-based TFTs fabricated on either glass or plastic substrates at low temperature (<100°C) exhibit good electrical properties: the saturation mobility of 5--12 cm2.V-1.s-1 and threshold voltage of 0.5--2.5V. The devices are also examined as a function of aging time in order to verify long-term stability in air. The effect of gate dielectric materials on electrical properties of InGaZnO 4-based TFTs was investigated. The use of SiNx film as a gate dielectric reduces the trap density and the roughness at the channel/gate dielectric interface compared to SiO2 gate dielectric, resulting in an improvement of device parameters by reducing scattering of trapped charges at the interface. The quality of interface is shown to have large effect on TFT performance

  4. Nitrous oxide emissions from wastewater treatment processes

    PubMed Central

    Law, Yingyu; Ye, Liu; Pan, Yuting; Yuan, Zhiguo

    2012-01-01

    Nitrous oxide (N2O) emissions from wastewater treatment plants vary substantially between plants, ranging from negligible to substantial (a few per cent of the total nitrogen load), probably because of different designs and operational conditions. In general, plants that achieve high levels of nitrogen removal emit less N2O, indicating that no compromise is required between high water quality and lower N2O emissions. N2O emissions primarily occur in aerated zones/compartments/periods owing to active stripping, and ammonia-oxidizing bacteria, rather than heterotrophic denitrifiers, are the main contributors. However, the detailed mechanisms remain to be fully elucidated, despite strong evidence suggesting that both nitrifier denitrification and the chemical breakdown of intermediates of hydroxylamine oxidation are probably involved. With increased understanding of the fundamental reactions responsible for N2O production in wastewater treatment systems and the conditions that stimulate their occurrence, reduction of N2O emissions from wastewater treatment systems through improved plant design and operation will be achieved in the near future. PMID:22451112

  5. Preparation, certification and interlaboratory analysis of workplace air filters spiked with high-fired beryllium oxide.

    PubMed

    Oatts, Thomas J; Hicks, Cheryl E; Adams, Amy R; Brisson, Michael J; Youmans-McDonald, Linda D; Hoover, Mark D; Ashley, Kevin

    2012-02-01

    Occupational sampling and analysis for multiple elements is generally approached using various approved methods from authoritative government sources such as the National Institute for Occupational Safety and Health (NIOSH), the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA), as well as consensus standards bodies such as ASTM International. The constituents of a sample can exist as unidentified compounds requiring sample preparation to be chosen appropriately, as in the case of beryllium in the form of beryllium oxide (BeO). An interlaboratory study was performed to collect analytical data from volunteer laboratories to examine the effectiveness of methods currently in use for preparation and analysis of samples containing calcined BeO powder. NIST SRM(®) 1877 high-fired BeO powder (1100 to 1200 °C calcining temperature; count median primary particle diameter 0.12 μm) was used to spike air filter media as a representative form of beryllium particulate matter present in workplace sampling that is known to be resistant to dissolution. The BeO powder standard reference material was gravimetrically prepared in a suspension and deposited onto 37 mm mixed cellulose ester air filters at five different levels between 0.5 μg and 25 μg of Be (as BeO). Sample sets consisting of five BeO-spiked filters (in duplicate) and two blank filters, for a total of twelve unique air filter samples per set, were submitted as blind samples to each of 27 participating laboratories. Participants were instructed to follow their current process for sample preparation and utilize their normal analytical methods for processing samples containing substances of this nature. Laboratories using more than one sample preparation and analysis method were provided with more than one sample set. Results from 34 data sets ultimately received from the 27 volunteer laboratories were subjected to applicable statistical analyses. The observed

  6. Preparation, certification and interlaboratory analysis of workplace air filters spiked with high-fired beryllium oxide.

    PubMed

    Oatts, Thomas J; Hicks, Cheryl E; Adams, Amy R; Brisson, Michael J; Youmans-McDonald, Linda D; Hoover, Mark D; Ashley, Kevin

    2012-02-01

    Occupational sampling and analysis for multiple elements is generally approached using various approved methods from authoritative government sources such as the National Institute for Occupational Safety and Health (NIOSH), the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA), as well as consensus standards bodies such as ASTM International. The constituents of a sample can exist as unidentified compounds requiring sample preparation to be chosen appropriately, as in the case of beryllium in the form of beryllium oxide (BeO). An interlaboratory study was performed to collect analytical data from volunteer laboratories to examine the effectiveness of methods currently in use for preparation and analysis of samples containing calcined BeO powder. NIST SRM(®) 1877 high-fired BeO powder (1100 to 1200 °C calcining temperature; count median primary particle diameter 0.12 μm) was used to spike air filter media as a representative form of beryllium particulate matter present in workplace sampling that is known to be resistant to dissolution. The BeO powder standard reference material was gravimetrically prepared in a suspension and deposited onto 37 mm mixed cellulose ester air filters at five different levels between 0.5 μg and 25 μg of Be (as BeO). Sample sets consisting of five BeO-spiked filters (in duplicate) and two blank filters, for a total of twelve unique air filter samples per set, were submitted as blind samples to each of 27 participating laboratories. Participants were instructed to follow their current process for sample preparation and utilize their normal analytical methods for processing samples containing substances of this nature. Laboratories using more than one sample preparation and analysis method were provided with more than one sample set. Results from 34 data sets ultimately received from the 27 volunteer laboratories were subjected to applicable statistical analyses. The observed

  7. Atomic structure and thermophysical properties of molten silver-copper oxide air braze alloys

    NASA Astrophysics Data System (ADS)

    Hardy, John Steven

    The Ag-CuOx materials system is the basis for a family of filler alloys used in a recently developed ceramic-metal joining technique referred to as air brazing, which is a brazing process that can be carried out in ambient air rather than under the vacuum or inert to reducing gas conditions required for conventional brazing methods. This research was conducted to elucidate the atomic coordination and selected thermophysical properties of these materials as a function of temperature when they are in the salient liquid state in air, since this is when the critical steps of wetting and spreading occur in the joining process. A series of alloys was selected spanning the entire length of the phase diagram including the pure end members, Ag and CuOx; alloys that form the two constituent single phase liquids; and alloys for which the two liquid phases coexist in the miscibility gap of the phase diagram. The oxygen content of the liquid alloys in air was measured using thermogravimetry. The oxidative weight gain of 99.999% pure metallic precursors was measured while simultaneously accounting for the concurrent silver volatility using a method that was developed in the course of the study. The surface tension and mass density were measured using the maximum bubble pressure method. The number density was calculated based on the information gained from the oxygen content and mass density measurements. For compositions that were amenable to laser heating, containerless high energy x-ray scattering measurements of the liquid atomic coordination were performed using a synchrotron beamline, an aerodynamic levitator, and laser heating. For the remaining compositions x-ray scattering measurements were performed in a beamline-compatible furnace. The two liquid phases that form in this materials system have distinct atomic coordinations characterized by an average of nearly two-fold coordinated ionic metal-oxygen pairs in the CuOx-rich liquid and nearly eight-fold coordinated atomic

  8. Evaluation of Foaming and Antifoam Effectiveness During the WTP Oxidative Leaching Process

    SciTech Connect

    Burket, P. R.; Jones, T. M.; White, T. L.; Crawford, C. L.; Calloway, T. B

    2005-10-11

    The River Protection Project-Waste Treatment Plant (RPP-WTP) requested Savannah River National Laboratory (SRNL) to conduct small-scale foaming and antifoam testing using a Hanford waste simulant subjected to air sparging during oxidative leaching. The foaminess of Hanford tank waste solutions was previously demonstrated by SRNL during WTP evaporator foaming studies and in small scale air sparger studies. The commercial antifoam, Dow Corning Q2-3183A was recommended to mitigate the foam in the evaporators and in vessel equipped with pulse jet mixers and air spargers. Currently, WTP is planning to use air spargers in the HLW Lag Storage Vessels (HLP-VSL-00027A/B), the Ultrafiltration Vessels (UFP-VSL-00002A&B), and the HLW Feed Blend Vessel (HLPVSL-00028) to assist the performance of the Pulse Jet Mixers (PJM). The previous air sparger antifoam studies conducted by SRNL researchers did not evaluate the hydrogen generation rate expected from antifoam additions or the effectiveness of the antifoam during caustic leaching or oxidative leaching. The fate of the various antifoam components and breakdown products in the WTP process under prototypic process conditions (temperature & radiation) was also not investigated. The effectiveness of the antifoam during caustic leaching, expected hydrogen generation rate associated with antifoam addition, and the fate of various antifoam components are being conducted under separate SRNL research tasks.

  9. Experimental Validation of Stratified Flow Phenomena, Graphite Oxidation, and Mitigation Strategies of Air Ingress Accidents

    SciTech Connect

    Chang Ho Oh; Eung Soo Kim; Hee Cheon No; Nam Zin Cho

    2008-12-01

    The US Department of Energy is performing research and development (R&D) that focuses on key phenomena that are important during challenging scenarios that may occur in the Next Generation Nuclear Plant (NGNP) Program / GEN-IV Very High Temperature Reactor (VHTR). Phenomena identification and ranking studies (PIRT) to date have identified the air ingress event, following on the heels of a VHTR depressurization, as very important (Schultz et al., 2006). Consequently, the development of advanced air ingress-related models and verification and validation (V&V) are very high priority for the NGNP program. Following a loss of coolant and system depressurization, air will enter the core through the break. Air ingress leads to oxidation of the in-core graphite structure and fuel. The oxidation will accelerate heat-up of the bottom reflector and the reactor core and will cause the release of fission products eventually. The potential collapse of the bottom reflector because of burn-off and the release of CO lead to serious safety problems. For estimation of the proper safety margin we need experimental data and tools, including accurate multi-dimensional thermal-hydraulic and reactor physics models, a burn-off model, and a fracture model. We also need to develop effective strategies to mitigate the effects of oxidation. The results from this research will provide crucial inputs to the INL NGNP/VHTR Methods R&D project. This project is focused on (a) analytical and experimental study of air ingress caused by density-driven, stratified, countercurrent flow, (b) advanced graphite oxidation experiments, (c) experimental study of burn-off in the bottom reflector, (d) structural tests of the burnt-off bottom reflector, (e) implementation of advanced models developed during the previous tasks into the GAMMA code, (f) full air ingress and oxidation mitigation analyses, (g) development of core neutronic models, (h) coupling of the core neutronic and thermal hydraulic models, and (i

  10. Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region

    PubMed Central

    Oikawa, P. Y.; Ge, C.; Wang, J.; Eberwein, J. R.; Liang, L. L.; Allsman, L. A.; Grantz, D. A.; Jenerette, G. D.

    2015-01-01

    Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality. PMID:26556236

  11. Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region.

    PubMed

    Oikawa, P Y; Ge, C; Wang, J; Eberwein, J R; Liang, L L; Allsman, L A; Grantz, D A; Jenerette, G D

    2015-01-01

    Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality. PMID:26556236

  12. Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region.

    PubMed

    Oikawa, P Y; Ge, C; Wang, J; Eberwein, J R; Liang, L L; Allsman, L A; Grantz, D A; Jenerette, G D

    2015-11-10

    Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality.

  13. Synthesis and characterization of carbon black/manganese oxide air cathodes for zinc-air batteries

    NASA Astrophysics Data System (ADS)

    Li, Po-Chieh; Hu, Chi-Chang; Lee, Tai-Chou; Chang, Wen-Sheng; Wang, Tsin Hai

    2014-12-01

    Due to the poor electric conductivity but the excellent catalytic ability for the oxygen reduction reaction (ORR), manganese dioxide in the α phase (denoted as α-MnO2) anchored onto carbon black powders (XC72) has been synthesized by the reflux method. The specific surface area and electric conductivity of the composites are generally enhanced by increasing the XC72 content while the high XC72 content will induce the formation of MnOOH which shows a worse ORR catalytic ability than α-MnO2. The ORR activity of such air cathodes have been optimized at the XC72/α-MnO2 ratio equal to 1 determined by the thermogravimetric analysis. By using this optimized cathode under the air atmosphere, the quasi-steady-state full-cell discharge voltages are equal to 1.353 and 1.178 V at 2 and 20 mA cm-2, respectively. Due to the usage of ambient air rather than pure oxygen, this Zn-air battery shows a modestly high discharge peak power density (67.51 mW cm-2) meanwhile the power density is equal to 47.22 mW cm-2 and the specific capacity is more than 750 mAh g-1 when this cell is operated at 1 V.

  14. Process for selected gas oxide removal by radiofrequency catalysts

    DOEpatents

    Cha, C.Y.

    1993-09-21

    This process to remove gas oxides from flue gas utilizes adsorption on a char bed subsequently followed by radiofrequency catalysis enhancing such removal through selected reactions. Common gas oxides include SO[sub 2] and NO[sub x]. 1 figure.

  15. Soot Surface Oxidation in Laminar Hydrocarbon/Air Diffusion Flames at Atmospheric Pressure. Appendix I

    NASA Technical Reports Server (NTRS)

    Xu, F.; El-Leathy, A. M.; Kim, C. H.; Faeth, G. M.; Yuan, Z.-G. (Technical Monitor); Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

    2003-01-01

    Soot surface oxidation was studied experimentally in laminar hydrocarbon/air diffusion flames at atmospheric pressure. Measurements were carried out along the axes of round fuel jets burning in coflowing dry air considering acetylene-nitrogen, ethylene, propyiene-nitrogen, propane and acetylene-benzene-nitrogen in the fuel stream. Measurements were limited to the initial stages of soot oxidation (carbon consumption less than 70%) where soot oxidation occurs at the surface of primary soot particles. The following properties were measured as a function of distance above the burner exit: soot concentrations by deconvoluted laser extinction, soot temperatures by deconvoluted multiline emission, soot structure by thermophoretic sampling and analysis using Transmission Electron Microscopy (TEM), concentrations of major stable gas species (N2, H2O, H2, O2, CO, CO2, CH4, C2H2, C2H6, C3H6, C3H8, and C6H6) by sampling and gas chromatography, concentrations of some radical species (H, OH, O) by deconvoluted Li/LiOH atomic absorption and flow velocities by laser velocimetry. For present test conditions, it was found that soot surface oxidation rates were not affected by fuel type, that direct rates of soot surface oxidation by O2 estimated from Nagle and Strickland-Constable (1962) were small compared to observed soot surface oxidation rates because soot surface oxidation was completed near the flame sheet where O2 concentrations were less than 3% by volume, and that soot surface oxidation rates were described by the OH soot surface oxidation mechanism with a collision efficiency of 0.14 and an uncertainty (95% confidence) of +/- 0.04 when allowing for direct soot surface oxidation by O2, which is in reasonably good agreement with earlier observations of soot surface oxidation rates in both premixed and diffusion flames at atmospheric pressure.

  16. Air-Driven Potassium Iodide-Mediated Oxidative Photocyclization of Stilbene Derivatives.

    PubMed

    Matsushima, Tomoya; Kobayashi, Sayaka; Watanabe, Soichiro

    2016-09-01

    A new method has been developed for the potassium iodide-mediated oxidative photocyclization of stilbene derivatives. Compared with conventional iodine-mediated oxidative photocyclization reactions, this new method requires shorter reaction times and affords cyclized products in yields of 45-97%. This reaction proceeds with a catalytic amount of potassium iodide and works in an air-driven manner without the addition of an external scavenger. The radical-mediated oxidative photocyclization of stilbene derivatives using TEMPO was also investigated. PMID:27508401

  17. Solid oxide fuel cell power plant having a fixed contact oxidation catalyzed section of a multi-section cathode air heat exchanger

    DOEpatents

    Saito, Kazuo; Lin, Yao

    2015-02-17

    The multi-section cathode air heat exchanger (102) includes at least a first heat exchanger section (104), and a fixed contact oxidation catalyzed section (126) secured adjacent each other in a stack association. Cool cathode inlet air flows through cool air channels (110) of the at least first (104) and oxidation catalyzed sections (126). Hot anode exhaust flows through hot air channels (124) of the oxidation catalyzed section (126) and is combusted therein. The combusted anode exhaust then flows through hot air channels (112) of the first section (104) of the cathode air heat exchanger (102). The cool and hot air channels (110, 112) are secured in direct heat exchange relationship with each other so that temperatures of the heat exchanger (102) do not exceed 800.degree. C. to minimize requirements for using expensive, high-temperature alloys.

  18. Catechol oxidation by ozone and hydroxyl radicals at the air-water interface.

    PubMed

    Pillar, Elizabeth A; Camm, Robert C; Guzman, Marcelo I

    2014-12-16

    Anthropogenic emissions of aromatic hydrocarbons promptly react with hydroxyl radicals undergoing oxidation to form phenols and polyphenols (e.g., catechol) typically identified in the complex mixture of humic-like substances (HULIS). Because further processing of polyphenols in secondary organic aerosols (SOA) can continue mediated by a mechanism of ozonolysis at interfaces, a better understanding about how these reactions proceed at the air-water interface is needed. This work shows how catechol, a molecular probe of the oxygenated aromatic hydrocarbons present in SOA, can contribute interfacial reactive species that enhance the production of HULIS under atmospheric conditions. Reactive semiquinone radicals are quickly produced upon the encounter of 40 ppbv-6.0 ppmv O3(g) with microdroplets containing [catechol] = 1-150 μM. While the previous pathway results in the instantaneous formation of mono- and polyhydroxylated aromatic rings (PHA) and chromophoric mono- and polyhydroxylated quinones (PHQ), a different channel produces oxo- and dicarboxylic acids of low molecular weight (LMW). The cleavage of catechol occurs at the 1,2 carbon-carbon bond at the air-water interface through the formation of (1) an ozonide intermediate, (2) a hydroperoxide, and (3) cis,cis-muconic acid. However, variable [catechol] and [O3(g)] can affect the ratio of the primary products (cis,cis-muconic acid and trihydroxybenzenes) and higher order products observed (PHA, PHQ, and LMW oxo- and dicarboxylic acids). Secondary processing is confirmed by mass spectrometry, showing the production of crotonic, maleinaldehydic, maleic, glyoxylic, and oxalic acids. The proposed pathway can contribute precursors to aqueous SOA (AqSOA) formation, converting aromatic hydrocarbons into polyfunctional species widely found in tropospheric aerosols with light-absorbing brown carbon.

  19. Catechol oxidation by ozone and hydroxyl radicals at the air-water interface.

    PubMed

    Pillar, Elizabeth A; Camm, Robert C; Guzman, Marcelo I

    2014-12-16

    Anthropogenic emissions of aromatic hydrocarbons promptly react with hydroxyl radicals undergoing oxidation to form phenols and polyphenols (e.g., catechol) typically identified in the complex mixture of humic-like substances (HULIS). Because further processing of polyphenols in secondary organic aerosols (SOA) can continue mediated by a mechanism of ozonolysis at interfaces, a better understanding about how these reactions proceed at the air-water interface is needed. This work shows how catechol, a molecular probe of the oxygenated aromatic hydrocarbons present in SOA, can contribute interfacial reactive species that enhance the production of HULIS under atmospheric conditions. Reactive semiquinone radicals are quickly produced upon the encounter of 40 ppbv-6.0 ppmv O3(g) with microdroplets containing [catechol] = 1-150 μM. While the previous pathway results in the instantaneous formation of mono- and polyhydroxylated aromatic rings (PHA) and chromophoric mono- and polyhydroxylated quinones (PHQ), a different channel produces oxo- and dicarboxylic acids of low molecular weight (LMW). The cleavage of catechol occurs at the 1,2 carbon-carbon bond at the air-water interface through the formation of (1) an ozonide intermediate, (2) a hydroperoxide, and (3) cis,cis-muconic acid. However, variable [catechol] and [O3(g)] can affect the ratio of the primary products (cis,cis-muconic acid and trihydroxybenzenes) and higher order products observed (PHA, PHQ, and LMW oxo- and dicarboxylic acids). Secondary processing is confirmed by mass spectrometry, showing the production of crotonic, maleinaldehydic, maleic, glyoxylic, and oxalic acids. The proposed pathway can contribute precursors to aqueous SOA (AqSOA) formation, converting aromatic hydrocarbons into polyfunctional species widely found in tropospheric aerosols with light-absorbing brown carbon. PMID:25423038

  20. AIR PARTICULATE POLLUTION EXPOSURE INDUCES SYSTEMIC OXIDATIVE STRESS IN HEALTHY MICE

    EPA Science Inventory

    Air particulate pollution exposure induces systemic oxidative stress in healthy mice

    Elizabeth S Roberts1 and Kevin L Dreher2. 1 College or Veterinary Medicine, NC State University, Raleigh, NC , 2US Environmental Protection Agency, NHEERL, RTP, NC

    Epidemiological s...

  1. COST ANALYSIS OF ACTIVATED CARBON VERSUS PHOTOCATALYTIC OXIDATION FOR REMOVING ORGANIC COMPOUNDS FROM INDOOR AIR

    EPA Science Inventory

    A cost comparison has been conducted of 1 m3/s indoor air cleaners using granular activated carbon (GAC) vs. photocatalytic oxidation (PCO) for treating a steady-state inlet volatile organic compound (VOC) concentration of 0.3 mg/m3. The commercial GAC unit was costed assuming t...

  2. Air Quality Criteria for Ozone and Related Photochemical Oxidants (First External Review Draft)

    EPA Science Inventory

    This first external review draft of the Air Quality Criteria for Ozone and Related Photochemical Oxidants (Ozone Criteria Document) is being released in January 2005 for public comment and for review by EPA's Clean A...

  3. IN VITRO CARDIOTOXICITY OF AIR POLLUTION PARTICLES: ROLE OF BIOAVAILABLE CONSTITUENTS, OXIDATIVE STRESS AND TYROSINE PHOSPHORYLATION

    EPA Science Inventory

    IN VITRO CARDIOTOXICITY OF AIR POLLUTION PARTICLES: ROLE OF BIOAVAILABLE CONSTITUENTS, OXIDATIVE STRESS AND TYROSINE PHOSPHORYLATION.

    T. L. Knuckles1 R. Jaskot2, J. Richards2, and K.Dreher2.
    1Department of Molecular and Biomedical Sciences, College of Veterinary Medicin...

  4. OXIDATION OF CYCLOHEXANE WITH AIR CATALYZED BY A STERICALLY HINDERED IRON (II) COMPLEX

    EPA Science Inventory

    Oxidation of Cyclohexane with Air Catalyzed by a Sterically Hindered Iron(II) Complex.


    Thomas M. Becker, Michael A. Gonzalez*

    United States Environmental Protection Agency; National Risk Management Research Laboratory; Sustainable Technology Division; Clean Pr...

  5. Enhanced reversibility and durability of a solid oxide Fe-air redox battery by carbothermic reaction derived energy storage materials.

    PubMed

    Zhao, Xuan; Li, Xue; Gong, Yunhui; Huang, Kevin

    2014-01-18

    The recently developed solid oxide metal-air redox battery is a new technology capable of high-rate chemistry. Here we report that the performance, reversibility and stability of a solid oxide iron-air redox battery can be significantly improved by nanostructuring energy storage materials from a carbothermic reaction.

  6. From particles to patients: oxidative stress and the cardiovascular effects of air pollution.

    PubMed

    Miller, Mark R; Shaw, Catherine A; Langrish, Jeremy P

    2012-07-01

    Air pollution, especially airborne particulate matter (PM), is associated with an increase in both morbidity and mortality from cardiovascular disease, although the underlying mechanisms remain incompletely established. The one consistent observation that links the pulmonary and cardiovascular effects of inhaled PM is oxidative stress. This article examines the evidence for the role of oxidative stress in the cardiovascular effects of air pollution, beginning with observations from epidemiological and controlled exposure studies and then exploring potential mechanistic pathways involving free radical generation from PM itself, to effects of PM on cell cultures, isolated organs, healthy animals and animal models of disease. Particular emphasis is placed on the vascular and atherosclerotic effects of urban air pollution and diesel exhaust emissions as rich sources of environmental ultrafine particles.

  7. Efficiencies for production of nitrogen oxides by proton impact in air

    NASA Astrophysics Data System (ADS)

    Rahman, Mahbubur; Cooray, Vernon; Possnert, Göran

    2013-03-01

    We present the first laboratory measurements of nitrogen oxides generated by proton impact in air. Experiments were conducted at the Tandem Laboratory of Uppsala University. A proton beam with known current and energy was injected into an air tight ionising chamber for a fixed time duration and the resulting nitrogen oxides were measured by the method of chemiluminescence. The data are presented in terms of number of produced NOX (NO+NO2) molecules for different proton energy, proton beam current and duration. The efficiency for NOX production by proton impact in air can on average be estimated to about 0.2 NOX molecules per ion-pair based on 1 cm diameter proton beam with energies from 2 to 4 MeV and varied currents from 0.1 to 10 nA.

  8. INVESTIGATION OF A NOVEL AIR BRAZING COMPOSITION FOR HIGH-TEMPERATURE, OXIDATION-RESISTANT CERAMIC JOINING

    SciTech Connect

    Weil, K. Scott; Hardy, John S.; Darsell, Jens T.

    2004-01-30

    One of the challenges in developing a useful ceramic joining technique is in producing a joint that offers good strength under high temperature and highly oxidizing operating conditions. Unfortunately many of the commercially available active metal ceramic brazing alloys exhibit oxidation behaviors which are unacceptable for use in a high temperature application. We have developed a new approach to ceramic brazing, referred to as air brazing, that employs an oxide wetting agent dissolved in a molten noble metal solvent, in this case CuO in Ag, such that acceptable wetting behavior occurs on a number of ceramic substrates. In an effort to explore how to increase the operating temperature of this type of braze, we have investigated the effect of ternary palladium additions on the wetting characteristics of our standard Ag-CuO air braze composition

  9. Effect of naturally occurring ozone air pollution episodes on pulmonary oxidative stress and inflammation.

    PubMed

    Pirozzi, Cheryl; Sturrock, Anne; Weng, Hsin-Yi; Greene, Tom; Scholand, Mary Beth; Kanner, Richard; Paine, Robert

    2015-05-12

    This study aimed to determine if naturally occurring episodes of ozone air pollution in the Salt Lake Valley in Utah, USA, during the summer are associated with increased pulmonary inflammation and oxidative stress, increased respiratory symptoms, and decreased lung function in individuals with chronic obstructive pulmonary disease (COPD) compared to controls. We measured biomarkers (nitrite/nitrate (NOx), 8-isoprostane) in exhaled breath condensate (EBC), spirometry, and respiratory symptoms in 11 former smokers with moderate-to-severe COPD and nine former smokers without airflow obstruction during periods of low and high ozone air pollution. High ozone levels were associated with increased NOx in EBC in both COPD (8.7 (±8.5) vs. 28.6 (±17.6) μmol/L on clean air vs. pollution days, respectively, p < 0.01) and control participants (7.6 (±16.5) vs. 28.5 (±15.6) μmol/L on clean air vs. pollution days, respectively, p = 0.02). There was no difference in pollution effect between COPD and control groups, and no difference in EBC 8-isoprostane, pulmonary function, or respiratory symptoms between clean air and pollution days in either group. Former smokers both with and without airflow obstruction developed airway oxidative stress and inflammation in association with ozone air pollution episodes.

  10. Contact allergens formed on air exposure of linalool. Identification and quantification of primary and secondary oxidation products and the effect on skin sensitization.

    PubMed

    Sköld, Maria; Börje, Anna; Harambasic, Elma; Karlberg, Ann-Therese

    2004-12-01

    Linalool (3,7-dimethyl-1,6-octadien-3-ol) is an important fragrance chemical, frequently used in scented products because of its fresh, flowery odor. Linalool is an unsaturated hydrocarbon and is therefore susceptible to oxidation in the presence of air. The primary oxidation products, that is, hydroperoxides, formed in the autoxidation process, are reactive compounds that can be suspected to act as sensitizers. In the present investigation, we studied the autoxidation of linalool with emphasis on the formation of hydroperoxides. The oxidation products were isolated using flash chromatography and preparative HPLC and were identified with NMR and GC/MS, using synthesized reference compounds. Two hydroperoxides and several different secondary oxidation products were identified, among which some contain structural features that make them potential allergens. The amounts of linalool and the major oxidation products were quantified over time, using GC and an HPLC-method, suitable for the analysis of thermolabile primary oxidation products. The hydroperoxide 7-hydroperoxy-3,7-dimethylocta-1,5-diene-3-ol was found to be present in 15% in an oxidized sample. The local lymph node assay (LLNA) was used to investigate the sensitizing potential of pure linalool, two samples of air-exposed linalool, and oxidation products of linalool (an alpha,beta-unsaturated aldehyde, a mixture of two hydroperoxides, and an alcohol). Pure linalool showed no sensitizing potential. The air-exposed samples of linalool produced clearly positive responses, and the hydroperoxides were the strongest allergens of the tested oxidation products. The study demonstrates the importance of autoxidation on the sensitizing potential of linalool. We also conclude that the sensitizing potential differs with the composition of the oxidation mixture and thus with the air exposure time.

  11. Solid oxide fuel cell process and apparatus

    DOEpatents

    Cooper, Matthew Ellis; Bayless, David J.; Trembly, Jason P.

    2011-11-15

    Conveying gas containing sulfur through a sulfur tolerant planar solid oxide fuel cell (PSOFC) stack for sulfur scrubbing, followed by conveying the gas through a non-sulfur tolerant PSOFC stack. The sulfur tolerant PSOFC stack utilizes anode materials, such as LSV, that selectively convert H.sub.2S present in the fuel stream to other non-poisoning sulfur compounds. The remaining balance of gases remaining in the completely or near H.sub.2S-free exhaust fuel stream is then used as the fuel for the conventional PSOFC stack that is downstream of the sulfur-tolerant PSOFC. A broad range of fuels such as gasified coal, natural gas and reformed hydrocarbons are used to produce electricity.

  12. Study of the formation process of titanium oxides containing micro arc oxidation film on Mg alloys

    NASA Astrophysics Data System (ADS)

    Song, Yingwei; Dong, Kaihui; Shan, Dayong; Han, En-Hou

    2014-09-01

    A novel micro arc oxidation (MAO) film is developed to protect Mg alloys from corrosion. This film contains plenty of titanium oxides, which exhibits higher chemical stability than traditional MAO films. Especially, the micropores on the surface of the film are in situ sealed during the film formation process instead of the sealing pores post treatment. The film formation process is investigated by the observation of surface and cross-section morphologies and analysis of chemical composition. It is found that the sizes of micropores increase but the quantities decrease with increasing oxidation voltages. The micropores are open in the initial stage of oxidation and then they are sealed gradually. The growth direction of the film takes place change at different oxidation voltages. The elements of F and Ti play a significant role in the film growth process.

  13. The role of oxidative processes in emphysema

    SciTech Connect

    Janoff, A.; Carp, H.; Laurent, P.; Raju, L.

    1983-02-01

    Elastase/elastase inhibitor imbalance in the lung has been implicated in the pathogenesis of pulmonary emphysema. In light of this, it may be significant that the activity of two major elastase inhibitors, alpha 1-proteinase inhibitor (alpha 1-antitrypsin, alpha 1Pi) and bronchial mucous proteinase inhibitor, can be decreased by oxidizing agents. The effect can be observed with ozone, substances present in cigarette smoke, and oxygen metabolites generated by lung macrophages as well as peroxidative systems released by other phagocytic cells. Thus alpha 1Pi recovered from lung washings of cigarette smokers has only half the predicted normal activity per mg inhibitor and contains 4 moles of methionine sulfoxide (oxidized methionine) per mole of inactive inhibitor. By contrast, alpha 1Pi purified from nonsmokers' lung washings is fully active and contains only native methionine. At the same time, lung washes from some smokers show significantly greater hydrolytic activity against a specific synthetic elastase substrate than do lung washes of nonsmokers. These findings suggest that some smokers may develop an acquired imbalance between elastase and elastase inhibitor in their lungs, favoring activity of the enzyme. In addition to the potential effect of cigarette smoking on lung elastase/elastase inhibitor balance, smoking also may interfere with elastin repair mechanisms. Specifically, acidic water-soluble gas phase components of cigarette smoke prevent synthesis of desmosine cross-links during elastinogenesis in vitro. This report will attempt to correlate the foregoing information on biochemical changes in the lung induced by cigarette smoking with the development of emphysema in the smoker.

  14. Interim results from UO/sub 2/ fuel oxidation tests in air

    SciTech Connect

    Campbell, T.K.; Gilbert, E.R.; Thornhill, C.K.; White, G.D.; Piepel, G.F.; Griffin, C.W.j

    1987-08-01

    An experimental program is being conducted at Pacific Northwest Laboratory (PNL) to extend the characterization of spent fuel oxidation in air. To characterize oxidation behavior of irradiated UO/sub 2/, fuel oxidation tests were performed on declad light-water reactor spent fuel and nonirradited UO/sub 2/ pellets in the temperature range of 135 to 250/sup 0/C. These tests were designed to determine the important independent variables that might affect spent fuel oxidation behavior. The data from this program, when combined with the test results from other programs, will be used to develop recommended spent fuel dry-storage temperature limits in air. This report describes interim test results. The initial PNL investigations of nonirradiated and spent fuels identified the important testing variables as temperature, fuel burnup, radiolysis of the air, fuel microstructure, and moisture in the air. Based on these initial results, a more extensive statistically designed test matrix was developed to study the effects of temperature, burnup, and moisture on the oxidation behavior of spent fuel. Oxidation tests were initiated using both boiling-water reactor and pressurized-water reactor fuels from several different reactors with burnups from 8 to 34 GWd/MTU. A 10/sup 5/ R/h gamma field was applied to the test ovens to simulate dry storage cask conditions. Nonirradiated fuel was included as a control. This report describes experimental results from the initial tests on both the spent and nonirradiated fuels and results to date on the tests in a 10/sup 5/ R/h gamma field. 33 refs., 51 figs., 6 tabs.

  15. Treatment of MTBE by air stripping, carbon adsorption, and advanced oxidation: technical and economic comparison for five groundwaters.

    PubMed

    Sutherland, J; Adams, C; Kekobad, J

    2004-01-01

    An investigation was made of the treatability of methyl tert-butyl ether (MTBE) in five groundwaters with highly varied water quality characteristics. Air stripping, granular activated carbon (GAC) adsorption, and the O(3)/H(2)O(2) and UV/H(2)O(2) advanced oxidation processes were compared in a mobile water treatment pilot plant under a variety of process conditions. Air stripping was shown to have the lower unit treatment costs for higher flowrates (i.e., 3800L/min), although relatively tall towers were required for greater treatment requirements. At low flowrates (i.e., 38L/min), advanced oxidation provided the lowest treatment costs for four of five waters (but was ineffective for a high chemical oxygen demand water). Both the O(3)/H(2)O(2) and UV/H(2)O(2) processes were more efficient at pH 7 versus 9 due in part to increased scavenging at higher pH. GAC was examined using rapid small-scale column tests (RSSCT). GAC was effective at most conditions, although it was also the most costly alternative for most waters. The results of this study can help to provide specific guidance into process selection for treating MTBE in contaminated groundwaters.

  16. Synthesis and characterization of carbon black/manganese oxide air cathodes for zinc-air batteries: Effects of the crystalline structure of manganese oxides

    NASA Astrophysics Data System (ADS)

    Li, Po-Chieh; Hu, Chi-Chang; Noda, Hiroyuki; Habazaki, Hiroki

    2015-12-01

    Manganese oxides (MnOx) in α-, β-, γ-, δ-MnO2 phases, Mn3O4, Mn2O3, and MnOOH are synthesized for systematically comparing their electrocatalytic activity of the oxygen reduction reaction (ORR) in the Zn-air battery application. The optimal MnOx/XC-72 mass ratio for the ORR is equal to 1 and the oxide crystalline structure effect on the ORR is compared. The order of composites with respect to decreasing the ORR activity is: α-MnO2/XC-72 > γ-MnO2/XC-72 > β-MnO2/XC-72 > δ-MnO2/XC-72 > Mn2O3/XC-72 > Mn3O4/XC-72 > MnOOH/XC-72. The textural properties of MnOx are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption/desorption isotherms with Brunauer-Emmett-Teller (BET) analysis, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Electrochemical studies include linear sweep voltammetry (LSV), rotating ring-disk electrode (RRDE) voltammetry, and the full-cell discharge test. The discharge peak power density of Zn-air batteries varies from 61.5 mW cm-2 (α-MnO2/XC-72) to 47.1 mW cm-2 (Mn3O4/XC-72). The maximum peak power density is 102 mW cm-2 for the Zn-air battery with an air cathode containing α-MnO2/XC-72 under an oxygen atmosphere when the carbon paper is 10AA. The specific capacity of all full-cell tests is higher than 750 mAh g-1 at all discharge current densities.

  17. Soot Oxidation in Hydrocarbon/Air Diffusion Flames at Atmospheric Pressure. Appendix K

    NASA Technical Reports Server (NTRS)

    Xu, F.; El-Leathy, A. M.; Faeth, G. M.; Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

    2001-01-01

    Soot oxidation was studied experimentally in laminar hydrocarbon/air diffusion flames at atmospheric pressure. Measurements were carried out along the axes of round jets burning in coflowing air considering acetylene, ethylene, propylene and propane as fuels. Measurements were limited to the initial stages of soot oxidation (carbon consumption less than 70%) where soot oxidation mainly occurs at the surface of primary soot particles. The following properties were measured as a function of distance above the burner exit: soot concentrations by deconvoluted laser extinction, soot temperatures by deconvoluted multiline emission, soot structure by thermophoretic sampling and analysis using Transmission Electron Microscopy (TEM), concentrations of stable major gas species (N2, H2O, H2, O2, CO, CO2, CH4, C2H2,C2H4, C2H6, C3H6, and C3H8) by sampling and gas chromatography, concentrations of some radical species (H, OH, O) by the deconvoluted Li/LiOH atomic absorption technique and flow velocities by laser velocimetry. It was found that soot surface oxidation rates are not particularly affected by fuel type for laminar diffusion flames and are described reasonably well by the OH surface oxidation mechanism with a collision efficiency of 0.10, (standard deviation of 0.07) with no significant effect of fuel type in this behavior; these findings are in good agreement with the classical laminar premixed flame measurements of Neoh et al. Finally, direct rates of surface oxidation by O2 were small compared to OH oxidation for present conditions, based on estimated O2 oxidation rates due to Nagle and Strickland-Constable (1962), because soot oxidation was completed near the flame sheet where O2 concentrations were less than 1.2% by volume.

  18. Soot Oxidation in Laminar Hydrocarbon/Air Diffusion Flames at Atmospheric Pressure. Appendix D

    NASA Technical Reports Server (NTRS)

    Xu, F.; El-Leathy, A. M.; Faeth, G. M.

    2000-01-01

    Soot oxidation was studied experimentally in laminar hydrocarbon/air diffusion flames at atmospheric pressure. Measurements were carried out along the axes of round jets burning in coflowing air considering acetylene, ethylene, proplyene and propane as fuels. Measurements were limited to the initial stages of soot oxidation (carbon consumption less than 70%) where soot oxidation mainly occurs at the surface of primary soot particles. The following properties were measured as a function of distance above the burner exit: soot concentrations by deconvoluted laser extinction, soot temperatures by deconvoluted multiline emission, soot structure by thermophoretic sampling and analysis using Transmission Electron Microscopy (TEM), concentrations of stable major gas species (N2, H2O, H2, 02, CO, CO2, CH4, C2H2, C2H4, C2H6, C3H6, and C3H8) by sampling and gas chromatography, concentrations of some radical species (H, OH, O) by the deconvoluted Li/LiOH atomic absorption technique and flow velocities by laser velocimetry. It was found that soot surface oxidation rates are not particularly affected by fuel type for laminar diffusion flames and are described reasonably well by the OH surface oxidation mechanism with a collision efficiency of 0.10, (standard deviation of 0.07) with no significant effect of fuel type in this behavior; these findings are in good agreement with the classical laminar premixed flame measurements of Neoh et al. Finally, direct rates of surface oxidation by O2 were small compared to OH oxidation for present conditions, based on estimated O2 oxidation rates due to Nagle and Strickland-Constable, because soot oxidation was completed near the flame sheet where O2 concentrations were less than 1.2% by volume.

  19. Literature review for oxalate oxidation processes and plutonium oxalate solubility

    SciTech Connect

    Nash, C. A.

    2015-10-01

    A literature review of oxalate oxidation processes finds that manganese(II)-catalyzed nitric acid oxidation of oxalate in precipitate filtrate is a viable and well-documented process. The process has been operated on the large scale at Savannah River in the past, including oxidation of 20 tons of oxalic acid in F-Canyon. Research data under a variety of conditions show the process to be robust. This process is recommended for oxalate destruction in H-Canyon in the upcoming program to produce feed for the MOX facility. Prevention of plutonium oxalate precipitation in filtrate can be achieved by concentrated nitric acid/ferric nitrate sequestration of oxalate. Organic complexants do not appear practical to sequester plutonium. Testing is proposed to confirm the literature and calculation findings of this review at projected operating conditions for the upcoming campaign.

  20. OH-Radical Oxidation of Surface-Active cis-Pinonic Acid at the Air-Water Interface.

    PubMed

    Enami, Shinichi; Sakamoto, Yosuke

    2016-05-26

    Gaseous biogenic volatile organic compounds (BVOCs) are immediately oxidized by gaseous oxidants to form BVOC-acids that rapidly condense onto aqueous aerosol phase and thus contribute to the growth of atmospheric particles. Because BVOC-acids are highly hydrophobic and hence surface-active in nature, it seems critical to study the oxidation by gaseous hydroxyl radical (·OH(g)) at the air-water interface. Here we report on the fast (≤10 μs) oxidation of aqueous cis-pinonic acid (C10H16O3, CPA, cis-pinonate anion's m/z = 183), a representative BVOC-acid, by ·OH(g) at the air-water interface for the first time. We find that cis-pinonate anion is more enriched at the air-water interface by ∼4 and ∼14 times than n-octanoate anion at 10 and 100 μM, respectively, as revealed by an interface-specific mass spectrometry of the equimolar mixture of microjets. Exposure of aqueous CPA microjets to ·OH(g) pulses from the 266 nm laser photolysis of O3(g)/O2(g)/H2O(g)/N2(g) mixtures yields pinonic peroxyl radicals (m/z = 214) that lead to the functionalization products carbonyls (m/z = 197), alcohols (m/z = 199), and pinonic hydroperoxides (m/z = 215) in addition to smaller-mass products including carbonyls (m/z = 155 and 157). We confirmed the formation of the corresponding alcohols, aldehydes, and hydroperoxides in experiments performed in D2O solvent. The analysis of total mass balance implies a significant amount (>70%) of products would be emitted into the gas-phase during the heterogeneous ·OH-oxidations. Our results suggest ·OH-oxidations of amphiphilic BVOC-acids at the air-water interface may play a far more significant role in photochemical aging process of aqueous aerosols than previously assumed. PMID:27098046

  1. Sliding durability of two carbide-oxide candidate high temperature fiber seal materials in air to 900 C

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Steinetz, Bruce M.

    1992-01-01

    A test program to determine the friction and wear properties of two complex carbide oxide ceramic fibers for high temperature sliding seal applications is described. The fibers are based on Si, C, O, and Ti or Si, C, N, and O ceramic systems. Pin on disk tests using ceramic fiber covered pins and Inconel 718 disks, were conducted in air from 25 to 900 C to evaluate potential seal materials. This testing procedure was used in a previous study of oxide ceramic fibers which were found to exhibit wear behavior based predominantly on their mechanical properties. Like the oxide fibers tested previously, these carbide oxide ceramic fibers, show an increase in friction and wear with increased test temperature. At room temperature, the wear behavior seems to be based upon mechanical properties, namely tensile strength. At 500 and especially 900 C, the fibers wear by both mechanical fracture and by oxidative type wear. Based upon post test microscopic and x ray analyses, interaction between the fiber constituents and elements transferred from the counterface, namely Ni and Cr, may have occurred enhancing the tribochemical wear process. These results are interpreted.

  2. Oxidant air pollution: estimated effects on US vegetation in 1969 and 1974

    SciTech Connect

    Moskowitz, P.D.; Medeiros, W.H.; Morris, S.C.; Coveney, E.A.

    1980-11-01

    In February 1979, the US Environmental Protection Agency (EPA) revised the primary and secondary ambient air quality standards for photochemical oxidants. This revision of the standards, based principally on critical review of health effects data, engendered considerable controversy. Several research efforts were subsequently initiated by EPA to develop data to support promulgation of future standards. Effects of air pollutants on vegetation are now being studied by the National Crop Loss Assessment Network (NCLAN) program. An initial element of the NCLAN effort was critical evaluation and preliminary quantitative economic estimation of oxidant effects on vegetation using the Benedict model. This report gives estimates of vegetation value and of loss caused by oxidants in 1969 and 1974 for 687 counties. Losses are estimated to be $1.3 x 10/sup 8/ and $2.9 x 10/sup 8/ in 1969 and 1974, respectively. These losses represent $1.5% of the total value of vegetation in the counties examined. Ornamentals in 1969 and Field Crops in 1974 dominated the total loss estimates. For agricultural crops, loss appeared to increase in the following order: Seed Crops, Citrus, Fruits and Nuts, Vegetables, and Field Crops. Geographic disaggregation of the estimates suggests that for both 1969 and 1974 oxidant loss was greatest in Federal Region IX, especially within the state of California. These estimates should be used with caution because they are based on subjective dose-response damage functions and on air quality measures that may be inaccurate.

  3. Process for preparing zinc oxide-based sorbents

    DOEpatents

    Gangwal, Santosh Kumar; Turk, Brian Scott; Gupta, Raghubir Prasad

    2011-06-07

    The disclosure relates to zinc oxide-based sorbents, and processes for preparing and using them. The sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents comprise an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, comprising a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

  4. [Mitochondria and oxidative stress participation in renal inflammatory process].

    PubMed

    Manucha, Walter

    2014-01-01

    The apoptosis and renal fibrosis are processes inherent to the chronic kidney disease, and consequently a clear deregulation of the mitochondrial respiratory mechanism has been described in patients with chronic renal disease associated to an increase of the oxidative stress. The injured tubular cells linked to the interstitial macrophages and myofibroblasts produce cytokines and growth factors that encourage an inflammatory condition, inducing the apoptosis of the tubular cells and enabling the accumulation of the extracellular matrix. The angiotensin II has a central role in the renal fibrogenesis leading to a rapid progression of the chronic kidney disease. The growing levels of the angiotensin II induce pro-inflammatory cytokines, the activation of NF-kB, adhesion molecules,chemokines, growth factors, and oxidative stress. The current evidence suggests that the angiotensin II increases the mitochondrial oxidative stress, regulates the induction of the apoptosis and conditions the inflammatory process. Therefore the mitochondria and the oxidative stress would play a determinant role in the renal inflammatory process. Finally, this review summarizes our present knowledge regarding the possible mechanisms that would contribute to the apoptosis conditioned by inflammation and/or oxidative stress during the chronic renal disease. Additionally, a new concept of the anti-inflammatory tools is proposed to regulate the mitochondrial oxidative stress that would directly affect the inflammatory process and apoptosis. This concept could have positive consequences on the treatment of renal inflammatory pathologies and related diseases.

  5. Lichen communities on conifers in Southern California mountains: an ecological survey relative to oxidant air pollution

    SciTech Connect

    Sigal, L.L.; Nash T.H. III

    1983-01-01

    In comparison with collections from the early 1900's when oxidant air pollution was essentially absent, 50% fewer lichen species were found on conifers during 3 yr (1976-1979) of collecting and sampling in the mountains of Southern California. Among the five mountain ranges studied, the San Bernardino Mountains, the region with the highest oxidant levels, had lower lichen frequency and cover values. Within the San Bernardino study sites, lichen cover was inversely related to estimated oxidant doses. Furthermore, at sites with high oxidant levels, marked morphological deterioration of the common species Hypogymnia enteromorpha was documented. Transplants of this species from the relatively unpolluted Cuyamaca Rancho State Park in the San Bernardino Mountains exhibited similar deterioration after a year's exposure.

  6. Lichen communities on conifers in Southern California mountains: an ecological survey relative to oxidant air pollution

    SciTech Connect

    Sigal, L.L.; Nash, T.H. III

    1983-01-01

    In comparison with collections from the early 1900's when oxidant air pollution was essentially absent, 50% fewer lichen species were found on conifers during 3 yr (1976-1979) of collecting and sampling in the mountains of Southern California. Among the five mountain ranges studied, the San Bernardino Mountains, the region with the highest oxidant levels, had lower lichen frequency and cover values. Within the San Bernardino study sites, lichen cover was inversely related to estimated oxidant doses. Furthermore, at sites with high oxidant levels, marked morphological deterioration of the common species Hypogymnia enteromorpha was documented. Transplants of this species from the relatively unpolluted Cuyamaca Rancho State Park into the San Bernardino Mountains exhibited similar deterioration after a year's exposure. 4 figures, 9 tables.

  7. Air Oxidation Behavior of Two Ti-Base Alloys Synthesized by HIP

    NASA Astrophysics Data System (ADS)

    Liu, S.; Guo, Q. Q.; Liu, L. L.; Xu, L.; Liu, Y. Y.

    2016-04-01

    The oxidation behavior of Ti-5Al-2.5Sn and Ti-6Al-4V produced by hot isostatic pressing (HIP) has been studied at 650-850°C in air for 24 h. The oxidation kinetics of both alloys followed the parabolic law with good approximation, except for Ti-5Al-2.5Sn oxidized at 850°C. Multi-layered scales formed on both alloys at 750°C and 850°C. Ternary additions of Sn and V accounted for the different morphology of the scales formed on these two alloys. In addition, the oxidation behavior of HIP alloys is compared with that of the corresponding cast alloys and the scaling mechanism is discussed.

  8. Surface-catalyzed air oxidation reactions of hydrazines: Tubular reactor studies

    NASA Technical Reports Server (NTRS)

    Kilduff, Jan E.; Davis, Dennis D.; Koontz, Steven L.

    1988-01-01

    The surface-catalyzed air oxidation reactions of hydrazine, monomethylhydrazine, unsymmetrical dimethylhydrazine, symmetrical dimethylhydrazine, trimethylhydrazine and tetramethylhydrazine were investigated in a metal-powder packed turbular flow reactor at 55 plus or minus 3 C. Hydrazine was completely reacted on all surfaces studied. The major products of monomethylhydrazine (MMH) oxidation were methanol, methane and methyldiazene. The di-, tri- and tetra-methyl hydrazines were essentially unreactive under these conditions. The relative catalytic reactivities toward MMH are: Fe greater than Al2O3 greater than Ti greater than Zn greater than 316 SS greater than Cr greater than Ni greater than Al greater than 304L SS. A kinetic scheme and mechanism involving adsorption, oxidative dehydrogenation and reductive elimination reactions on a metal oxide surface are proposed.

  9. The Measurement of Fuel-Air Ratio by Analysis for the Oxidized Exhaust Gas

    NASA Technical Reports Server (NTRS)

    Gerrish, Harold C.; Meem, J. Lawrence, Jr.

    1943-01-01

    An investigation was made to determine a method of measuring fuel-air ratio that could be used for test purposes in flight and for checking conventional equipment in the laboratory. Two single-cylinder test engines equipped with typical commercial engine cylinders were used. The fuel-air ratio of the mixture delivered to the engines was determined by direct measurement of the quantity of air and of fuel supplied and also by analysis of the oxidized exhaust gas and of the normal exhaust gas. Five fuels were used: gasoline that complied with Army-Navy fuel Specification No. AN-VV-F-781 and four mixtures of this gasoline with toluene, benzene, and xylene. The method of determining the fuel-air ratio described in this report involves the measurement of the carbon-dioxide content of the oxidized exhaust gas and the use of graphs for the presented equation. This method is considered useful in aircraft, in the field, or in the laboratory for a range of fuel-air ratios from 0.047 to 0.124.

  10. The Measurement of Fuel-air Ratio by Analysis of the Oxidized Exhaust Gas

    NASA Technical Reports Server (NTRS)

    Memm, J. Lawrence, Jr.

    1943-01-01

    An investigation was made to determine a method of measuring fuel-air ratio that could be used for test purposes in flight and for checking conventional equipment in the laboratory. Two single-cylinder test engines equipped with typical commercial engine cylinders were used. The fuel-air ratio of the mixture delivered to the engines was determined by direct measurement of the quantity of air and of fuel supplied and also by analysis of the oxidized exhaust gas and of the normal exhaust gas. Five fuels were used: gasoline that complied with Army-Navy Fuel Specification, No. AN-VV-F-781 and four mixtures of this gasoline with toluene, benzene, and xylene. The method of determining the fuel-air ratio described in this report involves the measurement of the carbon-dioxide content of the oxidized exhaust gas and the use of graphs or the presented equation. This method is considered useful in aircraft, in the field, or in the laboratory for a range of fuel-air ratios from 0.047 to 0.124

  11. Mobile air monitoring data-processing strategies and effects on spatial air pollution trends

    NASA Astrophysics Data System (ADS)

    Brantley, H. L.; Hagler, G. S. W.; Kimbrough, E. S.; Williams, R. W.; Mukerjee, S.; Neas, L. M.

    2014-07-01

    The collection of real-time air quality measurements while in motion (i.e., mobile monitoring) is currently conducted worldwide to evaluate in situ emissions, local air quality trends, and air pollutant exposure. This measurement strategy pushes the limits of traditional data analysis with complex second-by-second multipollutant data varying as a function of time and location. Data reduction and filtering techniques are often applied to deduce trends, such as pollutant spatial gradients downwind of a highway. However, rarely do mobile monitoring studies report the sensitivity of their results to the chosen data-processing approaches. The study being reported here utilized 40 h (> 140 000 observations) of mobile monitoring data collected on a roadway network in central North Carolina to explore common data-processing strategies including local emission plume detection, background estimation, and averaging techniques for spatial trend analyses. One-second time resolution measurements of ultrafine particles (UFPs), black carbon (BC), particulate matter (PM), carbon monoxide (CO), and nitrogen dioxide (NO2) were collected on 12 unique driving routes that were each sampled repeatedly. The route with the highest number of repetitions was used to compare local exhaust plume detection and averaging methods. Analyses demonstrate that the multiple local exhaust plume detection strategies reported produce generally similar results and that utilizing a median of measurements taken within a specified route segment (as opposed to a mean) may be sufficient to avoid bias in near-source spatial trends. A time-series-based method of estimating background concentrations was shown to produce similar but slightly lower estimates than a location-based method. For the complete data set the estimated contributions of the background to the mean pollutant concentrations were as follows: BC (15%), UFPs (26%), CO (41%), PM2.5-10 (45%), NO2 (57%), PM10 (60%), PM2.5 (68%). Lastly, while

  12. Catalytic wet air oxidation of carboxylic acids on TiO{sub 2}-supported ruthenium catalysts

    SciTech Connect

    Beziat, J.C.; Besson, M.; Gallezot, P.; Durecu, S.

    1999-02-15

    The total oxidation of aqueous solutions of carboxylic acids by air was studied in a slurry reactor over the temperature range 180--100 C and oxygen partial pressure of 0.3--1.8 MPa in the presence of a 2.8%Ru/TiO{sub 2} catalyst. The influence of various parameters is presented: the catalytic wet air oxidation of succinic acid is 0 order with respect to succinic acid; the order with respect to oxygen pressure is 0.4, and the activation energy is ca. 125 kJ/mol. It was found that acetic acid, which is one of the intermediates, and CO{sub 2} have no retarding effect on the total organic carbon abatement rate of succinic acid. Substitution of one hydrogen atom of the methyl group in acetic acid by Cl, OH, or NH{sub 2} gives an increase of the oxidation rate. However, it was proposed that the low activity of acetic acid oxidation is due not only to the difficulty to oxidize the methyl group, but also to the low adsorption coefficient of acetic acid on ruthenium surface. Inorganic salts, such as sodium chloride, only slightly decrease the oxidation rate of acetic acid. The absence of metal ions (Ru, Ti) in the effluents after reaction and the absence of particle sintering indicate also a high stability of the catalyst under the conditions employed. The catalyst can be recycled without loss of activity after the second run. The activity becomes stable after the attainment of a steady-state coverage of the Ru particles by oxygen. The study of the effect of reduction-oxidation treatments of the catalyst showed that the activity depends on the oxidation state of the surface.

  13. High-temperature processing of cuprate oxide superconductors

    NASA Technical Reports Server (NTRS)

    Wu, M. K.; Ashburn, J. R.; Higgins, C. A.; Fellows, C. W.; Loo, B. H.; Burns, D. H.; Ibrahim, A.; Rolin, T. D.; Peters, P. N.; Sisk, R. C.

    1988-01-01

    Superconducting Y1Ba2Cu3O7 ('123') films were fabricated on the Y2BaCuO5 ('211') phase substrate. The superconducting characteristics of these films, in terms of superconducting transition temperature (Tc) and width, are better than those using other oxide compounds as substrates. In addition, using high-temperature processing, the bulk 211 phase was converted into the 123 phase. A new high Tc copper oxide material with non-rare-earth elements (Bi-Sr-Cu-O) was prepared using similar high-temperature processing. High-temperature processing presents an alternative synthetic route in the search of new high Tc superconductors.

  14. Development studies of a novel wet oxidation process

    SciTech Connect

    Rogers, T.W.; Dhooge, P.M.

    1995-10-01

    Many DOE waste streams and remediates contain complex and variable mixtures of organic compounds, toxic metals, and radionuclides. These materials are often dispersed in organic or inorganic matrices, such as personal protective equipment, various sludges, soils, and water. Incineration and similar combustive processes do not appear to be viable options for treatment of these waste streams due to various considerations. The objective of this project is to develop a novel catalytic wet oxidation process for the treatment of multi-component wastes. The DETOX process uses a unique combination of metal catalysts to increase the rate of oxidation of organic materials.

  15. Oxidation processes in magneto-optic and related materials

    NASA Technical Reports Server (NTRS)

    Lee, Paul A.; Armstrong, Neal R.; Danzinger, James L.; England, Craig D.

    1992-01-01

    The surface oxidation processes of thin films of magneto-optic materials, such as the rare-earth transition metal alloys have been studied, starting in ultrahigh vacuum environments, using surface analysis techniques, as a way of modeling the oxidation processes which occur at the base of a defect in an overcoated material, at the instant of exposure to ambient environments. Materials examined have included FeTbCo alloys, as well as those same materials with low percentages of added elements, such a Ta, and their reactivities to both O2 and H2O compared with materials such as thin Fe films coated with ultrathin adlayers of Ti. The surface oxidation pathways for these materials is reviewed, and XPS data presented which indicates the type of oxides formed, and a critical region of Ta concentration which provides optimum protection.

  16. Mobile Air Monitoring Data Processing Strategies and Effects on Spatial Air Pollution Trends

    EPA Science Inventory

    The collection of real-time air quality measurements while in motion (i.e., mobile monitoring) is currently conducted worldwide to evaluate in situ emissions, local air quality trends, and air pollutant exposure. This measurement strategy pushes the limits of traditional data an...

  17. Scientists set to destroy VOCs with thermal oxidation process

    SciTech Connect

    Ray, K.A

    1989-12-01

    This paper reports on a thermal oxidation process that boasts a 99.99 percent destruction removal efficiency (DRE) and minimal formation of products of incomplete combustion (PICs). Together with a high reliability, corrosion resistant,non-catalytic design, these attributes make the technology ideal for processing chlorinated compounds, say company officials.

  18. Advanced oxidation processes with coke plant wastewater treatment.

    PubMed

    Krzywicka, A; Kwarciak-Kozłowska, A

    2014-01-01

    The aim of this study was to determine the most efficient method of coke wastewater treatment. This research examined two processes - advanced oxidation with Fenton and photo-Fenton reaction. It was observed that the use of ultraviolet radiation with Fenton process had a better result in removal of impurities.

  19. Development of techniques for processing metal-metal oxide systems

    NASA Technical Reports Server (NTRS)

    Johnson, P. C.

    1976-01-01

    Techniques for producing model metal-metal oxide systems for the purpose of evaluating the results of processing such systems in the low-gravity environment afforded by a drop tower facility are described. Because of the lack of success in producing suitable materials samples and techniques for processing in the 3.5 seconds available, the program was discontinued.

  20. Process of forming catalytic surfaces for wet oxidation reactions

    NASA Technical Reports Server (NTRS)

    Jagow, R. B. (Inventor)

    1977-01-01

    A wet oxidation process was developed for oxidizing waste materials, comprising dissolved ruthenium salt in a reactant feed stream containing the waste materials. The feed stream is introduced into a reactor, and the reactor contents are then raised to an elevated temperature to effect deposition of a catalytic surface of ruthenium black on the interior walls of the reactor. The feed stream is then maintained in the reactor for a period of time sufficient to effect at least partial oxidation of the waste materials.

  1. Review of research results for the photocatalytic oxidation of hazardous wastes in air

    SciTech Connect

    Nimlos, M R; Wolfrum, E J; Gratson, D A; Watt, A S; Jacoby, W A; Turchi, C

    1995-01-01

    Laboratory experiments of gas-phase photocatalytic oxidation (PCO) at NREL have focused on measurements that can help commercialize this technology for treating gaseous air streams. This effort proceeds earlier NREL work and studies conducted elsewhere which demonstrated the general applicability of PCO. The more recent work has concentrated on: (1) the kinetics of the PCO process; (2) the formation and destruction of intermediates; and (3) possible enhancements to improve the destruction rates. The results from these studies will be used to help design large scale PCO equipment and they will be used to evaluate the economics of the PCO process. For trichloroethylene and ethanol, extensive studies of the rates of destruction have yielded kinetic parameters for the destruction of intermediates as well as the substrate. The kinetics of intermediates is essential for sizing a large scale reactor, as complete conversion to carbon dioxide is often desired. The kinetic data from these laboratory studies has been used for analyzing IT`s pilot PCO reactor and has been used to suggest modifications to this unit. For compounds that are more difficult to destroy (such as the components of BTEX), rate enhancement experiments have been conducted. These compounds represent a very large market for this technology and improvement of the rate of the process should make it competitive. Towards this goal, the enhancement of the destruction of BTEX components have been studied. Experiments have demonstrated that there is a significant increase in the rates of destruction of BTEX with the addition of ozone. Preliminary economic assessments have shown that PCO with ozone may be cost competitive. Future laboratory experiments of PCO will focus on refinements of what has been learned. Rate measurements will also be expanded to include other compounds representing significant markets for the PCO technology.

  2. COLUMBIC OXIDE ADSORPTION PROCESS FOR SEPARATING URANIUM AND PLUTONIUM IONS

    DOEpatents

    Beaton, R.H.

    1959-07-14

    A process is described for separating plutonium ions from a solution of neutron irradiated uranium in which columbic oxide is used as an adsorbert. According to the invention the plutonium ion is selectively adsorbed by Passing a solution containing the plutonium in a valence state not higher than 4 through a porous bed or column of granules of hydrated columbic oxide. The adsorbed plutonium is then desorbed by elution with 3 N nitric acid.

  3. [Oxidative stress, antioxydants and the ageing process].

    PubMed

    Pincemail, J; Ricour, C; Defraigne, J O; Petermans, J

    2014-01-01

    Antioxidant supplementation in the form of pills is thought to slow down the aging process through the "free radical" scavenger activity of these compounds. The idea arose from the "Free Radical Theory of Ageing" (FRTA), initially developed by Harman in 1956. In the present paper, we present some arguments against this theory. One of the most pertinent is that "free radicals", more properly renamed as reactive oxygen species (ROS), play important biological roles in defense mechanisms of the organism as illustrated, in particular, by the hormesis phenomenon. Surprisingly, a moderate production of ROS has been shown to extend the life span in animals. PMID:25065231

  4. Contribution to the understanding of the ZrNb(l%)O(0.13%) oxidation mechanism at 500 °C in dry air

    NASA Astrophysics Data System (ADS)

    Vermoyal, J. J.; Frichet, A.; Dessemond, L.

    2004-06-01

    The oxidation of ZrNb(l%)O(0.13%) at 500 °C in dry air was investigated in situ by thermogravimetric analyses and electrochemical impedance spectroscopy. Sheets of the alloy were coated with different noble metals (Pt, Au, Ag) as electrode material. After an initial sub-parabolic rate law, the kinetics of ZrNb(l%)O(0.13%) oxidation are characterized by a transition to another decreasing rate law for different times and thicknesses. Noble metals were observed to clearly modify the oxidation rate, even when a pre-oxidized zirconia film was formed before the deposit and the increase in the oxidation rate was always monitored for thick oxides (30 μm). The kinetic transition is hypothesized to be associated with the microstructural degradation of the oxide film. Localized oxidation rate increases were revealed by scanning electron microscopy at the tip of radial cracks distributed on more than 2% of the total area of the sample. Catalytic effects observed on the oxidation rate after the noble metal deposition suggest that the mechanism controlling the oxidation rate is not a solely one of oxygen diffusion through the oxide layer. The reaction of oxygen reduction at the oxide/metal/gas interface partially controls the oxidation kinetics of ZrNb(l%)O(0.13%). Complex electrical signatures monitored during the oxide growth corroborate this assumption and hence indicate that oxygen reduction is still partially controlling the oxidation rate when noble metal are present on ZrNb(l%)O(0.13%) surface. Finally, a mixed process of interfacial-diffusion mechanism is proposed to be the rate determining step for ZrNb(l%)O(0.13%) oxidation in this environment.

  5. Oxidation of spent fuel in air at 175{degree} to 195{degree}C

    SciTech Connect

    Einziger, R.E.; Buchanan, H.C.; Thomas, L.E.; Stout, R.B.

    1992-04-01

    Oxidation tests in dry air were conducted on four LWR spent fuels at 175{degrees} and 195{degrees}C to determine the effect of the fuel characteristics on the oxidation state likely to exist at the time leaching occurs in a potential repository. Weight changes were measured and samples were examined by XRD, ceramography, TEM, and TGA. Despite local variations in the grain boundary susceptibility to oxidation, all four fuels progressed toward an apparent endpoint at an oxygen-to-metal (O/M) ratio of 2.4. The sole oxidation product was U{sub 4}O{sub 9+x,} a cubic phase structurally related to UO{sub 2} but with a slightly smaller lattice constant. The growth of the U{sub 4}O{sub 9+x} from the grain boundaries into the UO{sub 2} grains followed parabolic kinetics and had an activation energy of 26.6 kcal/mol. Based on the kinetics, the time required at 95{degrees}C to completely oxidize LWR spent fuel to U{sub 4}O{sub 9+x} would be at least 2000 yr. The next oxidation product to form after the U{sub 4}O{sub 9+x} phase may be U{sub 3}O{sub 8,} but no U{sub 3}O{sub 8} or other dilatational oxidation product has been detected in these accelerated tests conducted up to 25,000 h.

  6. Oxidation of spent fuel in air at 175 degree to 195 degree C

    SciTech Connect

    Einziger, R.E.; Buchanan, H.C.; Thomas, L.E. ); Stout, R.B. )

    1992-04-01

    Oxidation tests in dry air were conducted on four LWR spent fuels at 175{degrees} and 195{degrees}C to determine the effect of the fuel characteristics on the oxidation state likely to exist at the time leaching occurs in a potential repository. Weight changes were measured and samples were examined by XRD, ceramography, TEM, and TGA. Despite local variations in the grain boundary susceptibility to oxidation, all four fuels progressed toward an apparent endpoint at an oxygen-to-metal (O/M) ratio of 2.4. The sole oxidation product was U{sub 4}O{sub 9+x,} a cubic phase structurally related to UO{sub 2} but with a slightly smaller lattice constant. The growth of the U{sub 4}O{sub 9+x} from the grain boundaries into the UO{sub 2} grains followed parabolic kinetics and had an activation energy of 26.6 kcal/mol. Based on the kinetics, the time required at 95{degrees}C to completely oxidize LWR spent fuel to U{sub 4}O{sub 9+x} would be at least 2000 yr. The next oxidation product to form after the U{sub 4}O{sub 9+x} phase may be U{sub 3}O{sub 8,} but no U{sub 3}O{sub 8} or other dilatational oxidation product has been detected in these accelerated tests conducted up to 25,000 h.

  7. Oxidation Behavior and Mechanism of Pentlandite at 973 K (700 °C) in Air

    NASA Astrophysics Data System (ADS)

    Zhu, Huihui; Chen, Jun; Deng, Jinxia; Yu, Ranbo; Xing, Xianran

    2012-06-01

    The oxidation behavior of synthetic pentlandite at 973 K (700 °C) under isothermal conditions was investigated. The pentlandite sample (Ni,Fe)9S8 was synthesized from pure components and oxidized at 973 K (700 °C) in air in a muffle furnace. The phase identification and components analysis of the oxidation products were performed by using the Rietveld quantitative analysis method based on the powder X-ray diffraction (XRD) profiles and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX). The magnetic hysteresis loops were determined by a vibrating sample magnetometer. Fe2O3, Ni x Fe3- x O4, and NiO were dominant oxidation products, and their weight fractions changed in different ways along with the oxidation time. The nickel-rich phase and sulfur-rich phase were observed as intermediate phases in unreacted cores during oxidation, which led to the formation of gaps and holes. The oxidation reaction rate was rapid in the first 2 hours, and then it slowed down sharply.

  8. Laser Cladding to Improve Oxidation Behavior of Air Plasma-Sprayed Ni-20Cr Coating on Stainless Steel Substrate

    NASA Astrophysics Data System (ADS)

    Rauf, M. Mudassar; Shahid, Muhammad; Nusair Khan, A.; Mehmood, K.

    2015-09-01

    Air plasma-sprayed Ni-20Cr coating on stainless steel (AISI-304) substrate was re-melted using CO2 laser to remove the inherent defects, i.e., porosity, splat boundaries, and oxides of air plasma-sprayed coating. The (1) uncoated, (2) air plasma-sprayed, and (3) laser-re-melted specimens were exposed to cyclic oxidation at 900 °C for a hundred cycles run. The oxidation products were characterized using XRD and SEM. Weight changes were determined after every 4th cycle; Uncoated samples showed severe oxidation indicated by substantial weight loss, whereas air plasma-coated samples demonstrated noticeable weight gain. However, oxidation resistance of laser-cladded samples was found to be significantly improved as the samples showed negligible weight change; porosity within the coating was minimized with an improvement in interface quality causing reduction in delamination damage.

  9. Numerical Modeling of Oxidized 2D C/SiC Composites in Air Environments Below 900 °C: Microstructure and Elastic Properties

    NASA Astrophysics Data System (ADS)

    Sun, Zhigang; Chen, Xihui; Shao, Hongyan; Song, Yingdong

    2016-08-01

    A numerical model is presented for simulation of the oxidation-affected behaviors of two dimensional carbon fiber-reinforced silcon carbide matrix composite (2D C/SiC) exposed to air oxidizing environments below 900 °C, which incorporates the modeling of oxidized microstructure and computing of degraded elastic properties. This model is based upon the analysis of the representative volume cell (RVC) of the composite. The multi-scale model of 2D C/SiC composites is concerned in the present study. Analysis results of such a composite can provide a guideline for the real 2D C/SiC composite. The micro-structure during oxidation process is firstly modeled in the RVC. The elastic moduli of oxidized composite under non-stress oxidation environment is computed by finite element analysis. The elastic properties of 2D-C/SiC composites in air oxidizing environment are evaluated and validated in comparison to experimental data. The oxidation time, temperature and fiber volume fractions of C/SiC composite are investigated to show their influences upon the elastic properties of 2D C/SiC composites.

  10. Air-pressure tunable depletion width, rectification behavior, and charge conduction in oxide nanotubes.

    PubMed

    Alivov, Yahya; Funke, Hans H; Singh, Vivek; Nagpal, Prashant

    2015-02-01

    Metal-oxide nanotubes provide large surface areas and functionalizable surfaces for a variety of optical and electronic applications. Here we report air-tunable rectifying behavior, depletion width modulation, and two-dimensional (2D) charge conduction in hollow titanium-dioxide nanotubes. The metal contact forms a Schottky-diode in the nanotubes, and the rectification factor (on/off ratio) can be varied by more than 3 orders of magnitude (1-2 × 10(3)) as the air pressure is increased from 2 mTorr to atmospheric pressure. This behavior is explained using a change in depletion width of these thin nanotubes by adsorption of water vapor on both surfaces of a hollow nanotube, and the resulting formation of a metal-insulator-semiconductor (MIS) junction, which controls the 2D charge conduction properties in thin oxide nanotubes.

  11. A study of mercuric oxide and zinc-air battery life in hearing aids.

    PubMed

    Sparkes, C; Lacey, N K

    1997-09-01

    The requirement to phase out mercuric oxide (mercury) batteries on environmental grounds has led to the widespread introduction of zinc-air technology. The possibility arises that high drain hearing aids may not be adequately catered for by zinc-air cells, leading to poor performance. This study investigated the hearing aid user's ability to perceive differences between zinc-air and mercury cells in normal everyday usage. The data was collected for 100 experienced hearing aid users in field trials. Users report 50 per cent greater life for zinc-air cells in high power aids and 28 per cent in low power aids. The average life of the zinc-air cells range from 15 days in high power to 34 days in low power aids. Users are able to perceive a difference in sound quality in favour of zinc-air cells for low and medium power aids. The hearing aid population is not disadvantaged by phasing out mercury cells. PMID:9373545

  12. Resistance Measurements and Activation Energies Calculations of Pure and Platinum Doped Stannic Oxide Ceramics in Air

    SciTech Connect

    Ibrahim, Zuhairi; Othman, Zulkafli; Karim, Mohd Mustamam Abd; Holland, Diane

    2007-05-09

    Pure SnO2 and Pt-SnO2 ceramics were fabricated by the dry pressing method using a pressure of 40 Mpa and sintered at 1000 deg. C. Electrical resistance measurements were made using an impedance analyzer, in air and temperatures between 25 deg. C and 450 deg. C. The change in resistance in both pure and platinum-doped stannic oxide ceramics was discussed.

  13. Air, aqueous and thermal stabilities of Ce3+ ions in cerium oxide nanoparticle layers with substrates.

    PubMed

    Naganuma, Tamaki; Traversa, Enrico

    2014-06-21

    Abundant oxygen vacancies coexisting with Ce(3+) ions in fluorite cerium oxide nanoparticles (CNPs) have the potential to enhance catalytic ability, but the ratio of unstable Ce(3+) ions in CNPs is typically low. Our recent work, however, demonstrated that the abundant Ce(3+) ions created in cerium oxide nanoparticle layers (CNPLs) by Ar ion irradiation were stable in air at room temperature. Ce valence states in CNPs correlate with the catalytic ability that involves redox reactions between Ce(3+) and Ce(4+) ions in given application environments (e.g. high temperature in carbon monoxide gas conversion and immersion conditions in biomedical applications). To better understand the mechanism by which Ce(3+) ions achieve stability in CNPLs, we examined (i) extra-long air-stability, (ii) thermal stability up to 500 °C, and (iii) aqueous stability of Ce(3+) ions in water, buffer solution and cell culture medium. It is noteworthy that air-stability of Ce(3+) ions in CNPLs persisted for more than 1 year. Thermal stability results showed that oxidation of Ce(3+) to Ce(4+) occurred at 350 °C in air. Highly concentrated Ce(3+) ions in ultra-thin CNPLs slowly oxidized in water within 1 day, but stability was improved in the cell culture medium. Ce(3+) stability of CNPLs immersed in the medium was associated with phosphorus adsorption on the Ce(3+) sites. This study also illuminates the potential interaction mechanisms of stable Ce(3+) ions in CNPLs. These findings could be utilized to understand catalytic mechanisms of CNPs with abundant oxygen vacancies in their application environments.

  14. Pyrrhotite Oxidation as an Indicator of Air Entrainment into Eruption Columns

    NASA Astrophysics Data System (ADS)

    Matsumoto, K.; Nakamura, M.

    2015-12-01

    Fragmented magmas in eruption columns obtain buoyancy by entrainment and heating of cold air. Theoretically, the proportion of the entrained air and temperature change of the magma fragments can be calculated through rigorous fluid dynamics, but these factors have not been evaluated from natural pyroclasts. In this study, we developed a new method for quantifying the degree of air entrainment based on pyrrhotite (Po) oxidation reactions, whose time scale corresponds to the typical duration of (sub-) Plinian eruptions (i.e., tens of seconds to a few hours). We examined pumice clasts and lava flows from the 1914-15 eruption of Sakurajima. During this event, various types of eruption were observed: Plinian eruptions with intermittent generation of clastogenic lava flow, followed by voluminous effusive lava flow. The products of Po oxidation consisted of magnetite (Mt), hematite (Hm), and their composites. The occurrence of Po and the oxides were systematically correlated with the types of eruption. In Plinian pumices, unreacted Po ± porous Mt-Hm composite reaction rims were dominant, whereas in the clastogenic lava, porous Hm occurred predominantly with scarce unreacted Po and porous Mt. In the effusive lava, a variety of Po, Mt, and Hm assemblage was observed, but Po did not coexist with Hm-rims. The porous Mt crystals in the pumice clasts were found to be Ti-free, whereas those in the effusive lava had Ti-enriched rims. These correlations were explained by considering two factors: the achieved fO2, which was controlled by the extent of fragmentation (i.e., surface area exposed to air), and duration of the maintenance of a high-T and high-fO2 condition. This study has demonstrated that the cooling timescale of pumice clasts in eruption columns can be estimated through the rate of Po oxidation reactions Po→Mt and Mt→Hm. Lavas of clastogenic origin may also be recognized from the reaction.

  15. Microwave processing of ceramic oxide filaments. Annual report, FY1997

    SciTech Connect

    Vogt, G.J.

    1998-12-31

    The objective of the microwave filament processing project is to develop microwave techniques to manufacture continuous ceramic oxide filaments. Microwave processing uses the volumetric absorption of microwave power in oxide filament tows to drive off process solvents, to burn out organic binders, and to sinter the dried fibers to produce flexible, high-strength ceramic filaments. The technical goal is to advance filament processing technology by microwave heating more rapidly with less energy and at a lower cost than conventional processing, but with the same quality as conventional processing. The manufacturing goal is to collaborate with the 3M Company, a US manufacturer of ceramic oxide filaments, to evaluate the technology using a prototype filament system and to transfer the microwave technology to the 3M Company. Continuous ceramic filaments are a principal component in many advanced high temperature materials like continuous fiber ceramic composites (CFCC) and woven ceramic textiles. The use of continuous ceramic filaments in CFCC radiant burners, gas turbines, waste incineration, and hot gas filters in U.S. industry and power generation is estimated to save at least 2.16 quad/yr by year 2010 with energy cost savings of at least $8.1 billion. By year 2010, continuous ceramic filaments and CFCC`s have the potential to abate pollution emissions by 917,000 tons annually of nitrous oxide and 118 million tons annually of carbon dioxide (DOE Report OR-2002, February, 1994).

  16. Solid oxide fuel cells, and air electrode and electrical interconnection materials therefor

    DOEpatents

    Bates, J.L.

    1992-09-01

    In one aspect of the invention, an air electrode material for a solid oxide fuel cell comprises Y[sub 1[minus]a]Q[sub a]MnO[sub 3], where Q is selected from the group consisting of Ca and Sr or mixtures thereof and a' is from 0.1 to 0.8. Preferably, a' is from 0.4 to 0.7. In another aspect of the invention, an electrical interconnection material for a solid oxide fuel cell comprises Y[sub 1[minus]b]Ca[sub b]Cr[sub 1[minus]c]Al[sub c]O[sub 3], where b' is from 0.1 to 0.6 and c' is from 0 to 9.3. Preferably, b' is from 0.3 to 0.5 and c' is from 0.05 to 0.1. A composite solid oxide electrochemical fuel cell incorporating these materials comprises: a solid oxide air electrode and an adjacent solid oxide electrical interconnection which commonly include the cation Y, the air electrode comprising Y[sub 1[minus]a]Q[sub a]MnO[sub 3], where Q is selected from the group consisting of Ca and Sr or mixtures thereof and a' is from 0.1 to 0.8, the electrical interconnection comprising Y[sub 1[minus]b]Ca[sub b]Cr[sub 1[minus]c]Al[sub c]O[sub 3], where b' is from 0.1 to 0.6 and c' is from 0.0 to 0.3; a yttrium stabilized solid electrolyte comprising (1[minus]d)ZrO[sub 2]-(d)Y[sub 2]O[sub 3] where d' is from 0.06 to 0.5; and a solid fuel electrode comprising X-ZrO[sub 2], where X' is an elemental metal. 5 figs.

  17. Solid oxide fuel cells, and air electrode and electrical interconnection materials therefor

    DOEpatents

    Bates, J. Lambert

    1992-01-01

    In one aspect of the invention, an air electrode material for a solid oxide fuel cell comprises Y.sub.1-a Q.sub.a MnO.sub.3, where "Q" is selected from the group consisting of Ca and Sr or mixtures thereof and "a" is from 0.1 to 0.8. Preferably, "a" is from 0.4 to 0.7. In another aspect of the invention, an electrical interconnection material for a solid oxide fuel cell comprises Y.sub.1-b Ca.sub.b Cr.sub.1-c Al.sub.c O.sub.3, where "b" is from 0.1 to 0.6 and "c" is from 0 to 9.3. Preferably, "b" is from 0.3 to 0.5 and "c" is from 0.05 to 0.1. A composite solid oxide electrochemical fuel cell incorporating these materials comprises: a solid oxide air electrode and an adjacent solid oxide electrical interconnection which commonly include the cation Y, the air electrode comprising Y.sub.1-a Q.sub.a MnO.sub.3, where "Q" is selected from the group consisting of Ca and Sr or mixtures thereof and "a" is from 0.1 to 0.8, the electrical interconnection comprising Y.sub.1-b Ca.sub.b Cr.sub.1-c Al.sub.c O.sub.3, where "b" is from 0.1 to 0.6 and "c" is from 0.0 to 0.3; a yttrium stabilized solid electrolyte comprising (1-d)ZrO.sub.2 -(d)Y.sub.2 O.sub.3 where "d" is from 0.06 to 0.5; and a solid fuel electrode comprising X-ZrO.sub.2, where "X" is an elemental metal.

  18. LITERATURE REVIEW FOR OXALATE OXIDATION PROCESSES AND PLUTONIUM OXALATE SOLUBILITY

    SciTech Connect

    Nash, C.

    2012-02-03

    A literature review of oxalate oxidation processes finds that manganese(II)-catalyzed nitric acid oxidation of oxalate in precipitate filtrate is a viable and well-documented process. The process has been operated on the large scale at Savannah River in the past, including oxidation of 20 tons of oxalic acid in F-Canyon. Research data under a variety of conditions show the process to be robust. This process is recommended for oxalate destruction in H-Canyon in the upcoming program to produce feed for the MOX facility. Prevention of plutonium oxalate precipitation in filtrate can be achieved by concentrated nitric acid/ferric nitrate sequestration of oxalate. Organic complexants do not appear practical to sequester plutonium. Testing is proposed to confirm the literature and calculation findings of this review at projected operating conditions for the upcoming campaign. H Canyon plans to commence conversion of plutonium metal to low-fired plutonium oxide in 2012 for eventual use in the Mixed Oxide Fuel (MOX) Facility. The flowsheet includes sequential operations of metal dissolution, ion exchange, elution, oxalate precipitation, filtration, and calcination. All processes beyond dissolution will occur in HB-Line. The filtration step produces an aqueous filtrate that may have as much as 4 M nitric acid and 0.15 M oxalate. The oxalate needs to be removed from the stream to prevent possible downstream precipitation of residual plutonium when the solution is processed in H Canyon. In addition, sending the oxalate to the waste tank farm is undesirable. This report addresses the processing options for destroying the oxalate in existing H Canyon equipment.

  19. Mortality from asthma and chronic bronchitis associated with changes in sulfur oxides air pollution

    SciTech Connect

    Imai, M.; Yoshida, K.; Kitabatake, M.

    1986-01-01

    Death certificates issued in Yokkaichi, Japan, during the 21 yr from 1963 until 1983 were surveyed to determine the relationship between changes in air pollution and mortality due to bronchial asthma and chronic bronchitis. The following results were obtained. In response to worsening air pollution, mortality for bronchial asthma and chronic bronchitis began to increase. Mortality due to bronchial asthma decreased immediately in response to improvement of pollution, whereas mortality due to chronic bronchitis decreased to the level in the control area 4 to 5 yr after the concentration of sulfur dioxide (SO/sub 2/) began to satisfy the ambient air quality standard. In the polluted area, mortality due to bronchial asthma in subjects who were 20 yr of age was higher during the period in which higher concentrations of sulfur oxides were prevalent.

  20. Evaluation of Ultra-Violet Photocatalytic Oxidation for Indoor AirApplications

    SciTech Connect

    Hodgson, A.T.; Sullivan, D.P.; Fisk, W.J.

    2006-02-01

    Acceptable indoor air quality in office buildings may be achieved with less energy by combining effective air cleaning systems for volatile organic compounds (VOCs) with particle filtration then by relying solely on ventilation. For such applications, ultraviolet photocatalytic oxidation (UVPCO) systems are being developed for VOC destruction. An experimental evaluation of a UVPCO system is reported. The evaluation was unique in that it employed complex mixtures of VOCs commonly found in office buildings at realistically low concentrations. VOC conversion efficiencies varied over a broad range, usually exceeded 20%, and were as high as {approx}80%. Conversion efficiency generally diminished with increased air flow rate. Significant amounts of formaldehyde and acetaldehyde were produced due to incomplete mineralization. The results indicate that formaldehyde and acetaldehyde production rates may need to be reduced before such UVPCO systems can be deployed safely in occupied buildings.

  1. Process for combined control of mercury and nitric oxide.

    SciTech Connect

    Livengood, C. D.; Mendelsohn, M. H.

    1999-11-03

    Continuing concern about the effects of mercury in the environment may lead to requirements for the control of mercury emissions from coal-fired power plants. If such controls are mandated, the use of existing flue-gas cleanup systems, such as wet scrubbers currently employed for flue-gas desulfurization, would be desirable, Such scrubbers have been shown to be effective for capturing oxidized forms of mercury, but cannot capture the very insoluble elemental mercury (Hg{sup 0}) that can form a significant fraction of the total emissions. At Argonne National Laboratory, we have proposed and tested a concept for enhancing removal of Hg{sup 0}, as well as nitric oxide, through introduction of an oxidizing agent into the flue gas upstream of a scrubber, which readily absorbs the soluble reaction products. Recently, we developed a new method for introducing the oxidizing agent into the flue-gas stream that dramatically improved reactant utilization. The oxidizing agent employed was NOXSORB{trademark}, which is a commercial product containing chloric acid and sodium chlorate. When a dilute solution of this agent was introduced into a gas stream containing Hg{sup 0} and other typical flue-gas species at 300 F, we found that about 100% of the mercury was removed from the gas phase and recovered in process liquids. At the same time, approximately 80% of the nitric oxide was removed. The effect of sulfur dioxide on this process was also investigated and the results showed that it slightly decreased the amount of Hg{sup 0} oxidized while appearing to increase the removal of nitric oxide from the gas phase. We are currently testing the effects of variations in NOXSORB{trademark} concentration, sulfur dioxide concentration, nitric oxide concentration, and reaction time (residence time). Preliminary economic projections based on the results to date indicate that the chemical cost for nitric oxide oxidation could be less than $5,000/ton removed, while for Hg{sup 0} oxidation it

  2. Low cost stable air electrode material for high temperature solid oxide electrolyte electrochemical cells

    DOEpatents

    Kuo, Lewis J. H.; Singh, Prabhakar; Ruka, Roswell J.; Vasilow, Theodore R.; Bratton, Raymond J.

    1997-01-01

    A low cost, lanthanide-substituted, dimensionally and thermally stable, gas permeable, electrically conductive, porous ceramic air electrode composition of lanthanide-substituted doped lanthanum manganite is provided which is used as the cathode in high temperature, solid oxide electrolyte fuel cells and generators. The air electrode composition of this invention has a much lower fabrication cost as a result of using a lower cost lanthanide mixture, either a natural mixture or an unfinished lanthanide concentrate obtained from a natural mixture subjected to incomplete purification, as the raw material in place of part or all of the higher cost individual lanthanum. The mixed lanthanide primarily contains a mixture of at least La, Ce, Pr, and Nd, or at least La, Ce, Pr, Nd and Sm in its lanthanide content, but can also include minor amounts of other lanthanides and trace impurities. The use of lanthanides in place of some or all of the lanthanum also increases the dimensional stability of the air electrode. This low cost air electrode can be fabricated as a cathode for use in high temperature, solid oxide fuel cells and generators.

  3. Low cost stable air electrode material for high temperature solid oxide electrolyte electrochemical cells

    DOEpatents

    Kuo, L.J.H.; Singh, P.; Ruka, R.J.; Vasilow, T.R.; Bratton, R.J.

    1997-11-11

    A low cost, lanthanide-substituted, dimensionally and thermally stable, gas permeable, electrically conductive, porous ceramic air electrode composition of lanthanide-substituted doped lanthanum manganite is provided which is used as the cathode in high temperature, solid oxide electrolyte fuel cells and generators. The air electrode composition of this invention has a much lower fabrication cost as a result of using a lower cost lanthanide mixture, either a natural mixture or an unfinished lanthanide concentrate obtained from a natural mixture subjected to incomplete purification, as the raw material in place of part or all of the higher cost individual lanthanum. The mixed lanthanide primarily contains a mixture of at least La, Ce, Pr, and Nd, or at least La, Ce, Pr, Nd and Sm in its lanthanide content, but can also include minor amounts of other lanthanides and trace impurities. The use of lanthanides in place of some or all of the lanthanum also increases the dimensional stability of the air electrode. This low cost air electrode can be fabricated as a cathode for use in high temperature, solid oxide fuel cells and generators. 4 figs.

  4. Evaluation of the intrinsic photocatalytic oxidation kinetics of indoor air pollutants.

    PubMed

    Salvadó-Estivill, Ignasi; Hargreaves, David M; Puma, Gianluca Li

    2007-03-15

    This paper presents a methodology for the evaluation of the intrinsic photocatalytic oxidation (PCO) kinetics of indoor air pollutants. It combines computational fluid dynamics (CFD) modeling of the fluid flow in the reactor with radiation field modeling and photocatalytic reaction kinetics to yield a rigorous model of a flat-plate, single-pass, flow-through photocatalytic reactor for indoor air purification. This method was applied to model the PCO of trichloroethylene (TCE) in humidified air and to derive kinetic parameters directly from kinetic data in an integral flow reactor. Steady-state PCO experiments of TCE over irradiated TiO2 (Degussa P25) thin films immobilized on glass supports were carried out at different radiation intensities, flow rates, and inlet substrate concentrations. The oxidation rate of TCE was found to be first-order on the incident photon flux and to follow a Langmuir-Hinshelwood type reaction kinetics rate law. Mass transfer resistances were observed at Reynolds numbers less than 46. Apparent quantum yields were found to be up to 0.97 mol Einstein(-1). A comparison of the model prediction with the experimental results in an integral reactor yielded pollutant-specific kinetic rate parameters which were independent of reactor geometry, radiation field, and fluid-dynamics. The kinetic parameters would,therefore, be more universally applicable to the design and scale-up of photocatalytic reactors for indoor air purification.

  5. Physical characterization of a new composition of oxidized zirconium-2.5 wt% niobium produced using a two step process for biomedical applications

    NASA Astrophysics Data System (ADS)

    Pawar, V.; Weaver, C.; Jani, S.

    2011-05-01

    Zirconium and particularly Zr-2.5 wt%Nb (Zr2.5Nb) alloy are useful for engineering bearing applications because they can be oxidized in air to form a hard surface ceramic. Oxidized zirconium (OxZr) due to its abrasion resistant ceramic surface and biocompatible substrate alloy has been used as a bearing surface in total joint arthroplasty for several years. OxZr is characterized by hard zirconium oxide (oxide) formed on Zr2.5Nb using one step thermal oxidation carried out in air. Because the oxide is only at the surface, the bulk material behaves like a metal, with high toughness. The oxide, furthermore, exhibits high adhesion to the substrate because of an oxygen-rich diffusion hardened zone (DHZ) interposing between the oxide and the substrate. In this study, we demonstrate a two step process that forms a thicker DHZ and thus increased depth of hardening than that can be obtained using a one step oxidation process. The first step is thermal oxidation in air and the second step is a heat treatment in vacuum. The second step drives oxygen from the oxide formed in the first step deeper into the substrate to form a thicker DHZ. During the process only a portion of the oxide is dissolved. This new composition (DHOxZr) has approximately 4-6 μm oxide similar to that of OxZr. The nano-hardness of the oxide is similar but the DHZ is approximately 10 times thicker. The stoichiometry of the oxide is similar and a secondary phase rich in oxygen is present through the entire thickness. Due to the increased depth of hardening, the critical load required for the onset of oxide cracking is approximately 1.6 times more than that of the oxide of OxZr. This new composition has a potential to be used as a bearing surface in applications where greater depth of hardening is required.

  6. Oxidation of Black Carbon by Biotic and Abiotic Processes

    SciTech Connect

    Cheng, Chih-hsin; Lehmann, Johannes C.; Thies, Janice E.; Burton, Sarah D.; Engelhard, Mark H.

    2006-11-01

    The objectives of this study were to quantify the relative importance of either biotic or abiotic oxidation of biomass-derived black carbon (BC) and to characterize the surface properties and charge characteristics of oxidized particulate BC. We incubated BC and BC-soil mixtures at two different temperatures (30 C and 70 C) with and without microbial inoculation, nutrient additions, or manure amendments for four months. Abiotic processes were more important for oxidation of BC than biotic processes during this short-term incubation, as inoculation with microorganisms did not change any of the measured parameters. Black C incubated at both 30 C and 70 C without microbial activity showed dramatic decreases in pH (in water) from 5.4 to 5.2 and 3.4, as well as increases in cation exchange capacity (CEC at pH 7) by 53% and 538% and in oxygen (O) contents by 4% and 38%, respectively. Boehm titration and Fourier transform infrared (FTIR) spectroscopy suggested that the formation of carboxylic functional groups was the reason for the enhanced CEC during oxidation. The analyses of BC surface properties by X-ray photoelectron spectroscopy (XPS) indicated that the oxidation of BC particles initiated on the surface. Incubation at 30 C only enhanced oxidation on particle surfaces, while oxidation during incubation at 70 C penetrated into the interior of particles. Such short-term oxidation of BC has great significance for the stability of BC in soils as well as for its effects on soil fertility and biogeochemistry.

  7. Removal of ammonia from air on molybdenum and tungsten oxide modified activated carbons.

    PubMed

    Petit, Camille; Bandosz, Teresa J

    2008-04-15

    Microporous coconut-based activated carbon was impregnated with solutions of ammonium metatungstate or ammonium molybdate and then calcined in air in order to convert the salts into their corresponding oxides. The surface of those materials was characterized using adsorption of nitrogen, potentiometric titration, Fourier-transform infrared spectroscopy, X-ray diffraction, and thermal analysis. The results indicated a significant increase in surface acidity related to the presence of tungsten or molybdenum oxides. On the materials obtained, adsorption of ammonia from either dry or moist air was carried out. The oxides distributed on the surface provided Lewis and/or Brønsted centers for interactions with ammonia molecules or ammonium ions. Water on the surface of carbon or in the gas phase increased the amount of ammonia adsorbed via involvement of Brønsted-type interactions and/or by leading to the formation of molybdate or tungstate salts on the surface. Although the amount of ammonia adsorbed is closely related to the number of moles of oxides and their acidic centers, the carbon surface also contributes to the adsorption via providing small pores where ammonia can be dissolved in the water film.

  8. Impact of clay mineral on air oxidation of PAH-contaminated soils.

    PubMed

    Biache, Coralie; Kouadio, Olivier; Lorgeoux, Catherine; Faure, Pierre

    2014-09-01

    This work investigated the impact of a clay mineral (bentonite) on the air oxidation of the solvent extractable organic matters (EOMs) and the PAHs from contaminated soils. EOMs were isolated from two coking plant soils and mixed with silica sand or bentonite. These samples, as well as raw soils and bentonite/soil mixtures, were oxidized in air at 60 and 100 °C for 160 days. Mineralization was followed by measuring the CO2 produced over the experiments. EOM, polycyclic aromatic compound (PAC), including PAH, contents were also determined. Oxidation led to a decrease in EOM contents and PAH concentrations, these diminutions were enhanced by the presence of bentonite. Transfer of carbon from EOM to insoluble organic matter pointed out a condensation phenomenon leading to a stabilization of the contamination. Higher mineralization rates, observed during the oxidation of the soil/bentonite mixtures, seem to indicate that this clay mineral had a positive influence on the transformation of PAC into CO2.

  9. In situ secondary organic aerosol formation from ambient pine forest air using an oxidation flow reactor

    NASA Astrophysics Data System (ADS)

    Palm, B. B.; Campuzano-Jost, P.; Ortega, A. M.; Day, D. A.; Kaser, L.; Jud, W.; Karl, T.; Hansel, A.; Hunter, J. F.; Cross, E. S.; Kroll, J. H.; Peng, Z.; Brune, W. H.; Jimenez, J. L.

    2015-11-01

    Ambient air was oxidized by OH radicals in an oxidation flow reactor (OFR) located in a montane pine forest during the BEACHON-RoMBAS campaign to study biogenic secondary organic aerosol (SOA) formation and aging. High OH concentrations and short residence times allowed for semi-continuous cycling through a large range of OH exposures ranging from hours to weeks of equivalent (eq.) atmospheric aging. A simple model is derived and used to account for the relative time scales of condensation of low volatility organic compounds (LVOCs) onto particles, condensational loss to the walls, and further reaction to produce volatile, non-condensing fragmentation products. More SOA production was observed in the OFR at nighttime (average 4 μg m-3 when LVOC fate corrected) compared to daytime (average 1 μg m-3 when LVOC fate corrected), with maximum formation observed at 0.4-1.5 eq. days of photochemical aging. SOA formation followed a similar diurnal pattern to monoterpenes, sesquiterpenes, and toluene + p-cymene concentrations, including a substantial increase just after sunrise at 07:00 LT. Higher photochemical aging (> 10 eq. days) led to a decrease in new SOA formation and a loss of preexisting OA due to heterogeneous oxidation followed by fragmentation and volatilization. When comparing two different commonly used methods of OH production in OFRs (OFR185 and OFR254), similar amounts of SOA formation were observed. We recommend the OFR185 mode for future forest studies. Concurrent gas-phase measurements of air after OH oxidation illustrate the decay of primary VOCs, production of small oxidized organic compounds, and net production at lower ages followed by net consumption of terpenoid oxidation products as photochemical age increased. New particle formation was observed in the reactor after oxidation, especially during times when precursor gas concentrations and SOA formation were largest. Approximately 6 times more SOA was formed in the reactor from OH oxidation than

  10. Oxidation mechanisms of CF2Br2 and CH2Br2 induced by air nonthermal plasma.

    PubMed

    Schiorlin, Milko; Marotta, Ester; Dal Molin, Marta; Paradisi, Cristina

    2013-01-01

    Oxidation mechanisms in air nonthermal plasma (NTP) at room temperature and atmospheric pressure were investigated in a corona reactor energized by +dc, -dc, or +pulsed high voltage.. The two bromomethanes CF(2)Br(2) and CH(2)Br(2) were chosen as model organic pollutants because of their very different reactivities with OH radicals. Thus, they served as useful mechanistic probes: they respond differently to the presence of humidity in the air and give different products. By FT-IR analysis of the postdischarge gas the following products were detected and quantified: CO(2) and CO in the case of CH(2)Br(2), CO(2) and F(2)C ═ O in the case of CF(2)Br(2). F(2)C ═ O is a long-lived oxidation intermediate due to its low reactivity with atmospheric radicals. It is however removed from the NTP processed gas by passage through a water scrubber resulting in hydrolysis to CO(2) and HF. Other noncarbon containing products of the discharge were also monitored by FT-IR analysis, including HNO(3) and N(2)O. Ozone, an important product of air NTP, was never detected in experiments with CF(2)Br(2) and CH(2)Br(2) because of the highly efficient ozone depleting cycles catalyzed by BrOx species formed from the bromomethanes. It is concluded that, regardless of the type of corona applied, CF(2)Br(2) reacts in air NTP via a common intermediate, the CF(2)Br radical. The possible reactions leading to this radical are discussed, including, for -dc activation, charge exchange with O(2)(-), a species detected by APCI mass spectrometry. PMID:23190335

  11. Ellipsometric characterization of ethylene oxide-butylene oxide diblock copolymer adsorption at the air-water interface.

    PubMed

    Blomqvist, B Rippner; Benjamins, J-W; Nylander, T; Arnebrant, T

    2005-05-24

    Ellipsometry was used to determine the adsorbed layer thickness (d) and the surface excess (adsorbed amount, Gamma) of a nonionic diblock copolymer, E(106)B(16), of poly(ethylene oxide) (E) and poly(butylene oxide) (B) at the air-water interface. The results were obtained (i) by the conventional ellipsometric evaluation procedure using the change of both ellipsometric angles Psi and Delta and (ii) by using the change of Delta only and assuming values of the layer thickness. It was demonstrated that the calculated surface excesses from the different methods were in close agreement, independent of the evaluation procedure, with a plateau adsorption of about 2.5 mg/m(2) (400 A(2)/molecule). Furthermore, the amount of E(106)B(16) adsorbed at the air-water interface was found to be almost identical to that adsorbed from aqueous solution onto a hydrophobic solid surface. In addition, the possibility to use combined measurements with H(2)O or D(2)O as substrates to calculate values of d and Gamma was investigated and discussed. We also briefly discuss within which limits the Gibbs equation can be used to determine the surface excess of polydisperse block copolymers. PMID:15896051

  12. Air-stable superparamagnetic metal nanoparticles entrapped in graphene oxide matrix

    NASA Astrophysics Data System (ADS)

    Tuček, Jiří; Sofer, Zdeněk; Bouša, Daniel; Pumera, Martin; Holá, Kateřina; Malá, Aneta; Poláková, Kateřina; Havrdová, Markéta; Čépe, Klára; Tomanec, Ondřej; Zbořil, Radek

    2016-09-01

    Superparamagnetism is a phenomenon caused by quantum effects in magnetic nanomaterials. Zero-valent metals with diameters below 5 nm have been suggested as superior alternatives to superparamagnetic metal oxides, having greater superspin magnitudes and lower levels of magnetic disorder. However, synthesis of such nanometals has been hindered by their chemical instability. Here we present a method for preparing air-stable superparamagnetic iron nanoparticles trapped between thermally reduced graphene oxide nanosheets and exhibiting ring-like or core-shell morphologies depending on iron concentration. Importantly, these hybrids show superparamagnetism at room temperature and retain it even at 5 K. The corrected saturation magnetization of 185 Am2 kg-1 is among the highest values reported for iron-based superparamagnets. The synthetic concept is generalized exploiting functional groups of graphene oxide to stabilize and entrap cobalt, nickel and gold nanoparticles, potentially opening doors for targeted delivery, magnetic separation and imaging applications.

  13. Air-stable superparamagnetic metal nanoparticles entrapped in graphene oxide matrix

    PubMed Central

    Tuček, Jiří; Sofer, Zdeněk; Bouša, Daniel; Pumera, Martin; Holá, Kateřina; Malá, Aneta; Poláková, Kateřina; Havrdová, Markéta; Čépe, Klára; Tomanec, Ondřej; Zbořil, Radek

    2016-01-01

    Superparamagnetism is a phenomenon caused by quantum effects in magnetic nanomaterials. Zero-valent metals with diameters below 5 nm have been suggested as superior alternatives to superparamagnetic metal oxides, having greater superspin magnitudes and lower levels of magnetic disorder. However, synthesis of such nanometals has been hindered by their chemical instability. Here we present a method for preparing air-stable superparamagnetic iron nanoparticles trapped between thermally reduced graphene oxide nanosheets and exhibiting ring-like or core-shell morphologies depending on iron concentration. Importantly, these hybrids show superparamagnetism at room temperature and retain it even at 5 K. The corrected saturation magnetization of 185 Am2 kg–1 is among the highest values reported for iron-based superparamagnets. The synthetic concept is generalized exploiting functional groups of graphene oxide to stabilize and entrap cobalt, nickel and gold nanoparticles, potentially opening doors for targeted delivery, magnetic separation and imaging applications. PMID:27628898

  14. Air-stable superparamagnetic metal nanoparticles entrapped in graphene oxide matrix.

    PubMed

    Tuček, Jiří; Sofer, Zdeněk; Bouša, Daniel; Pumera, Martin; Holá, Kateřina; Malá, Aneta; Poláková, Kateřina; Havrdová, Markéta; Čépe, Klára; Tomanec, Ondřej; Zbořil, Radek

    2016-01-01

    Superparamagnetism is a phenomenon caused by quantum effects in magnetic nanomaterials. Zero-valent metals with diameters below 5 nm have been suggested as superior alternatives to superparamagnetic metal oxides, having greater superspin magnitudes and lower levels of magnetic disorder. However, synthesis of such nanometals has been hindered by their chemical instability. Here we present a method for preparing air-stable superparamagnetic iron nanoparticles trapped between thermally reduced graphene oxide nanosheets and exhibiting ring-like or core-shell morphologies depending on iron concentration. Importantly, these hybrids show superparamagnetism at room temperature and retain it even at 5 K. The corrected saturation magnetization of 185 Am(2) kg(-1) is among the highest values reported for iron-based superparamagnets. The synthetic concept is generalized exploiting functional groups of graphene oxide to stabilize and entrap cobalt, nickel and gold nanoparticles, potentially opening doors for targeted delivery, magnetic separation and imaging applications. PMID:27628898

  15. Air-stable superparamagnetic metal nanoparticles entrapped in graphene oxide matrix.

    PubMed

    Tuček, Jiří; Sofer, Zdeněk; Bouša, Daniel; Pumera, Martin; Holá, Kateřina; Malá, Aneta; Poláková, Kateřina; Havrdová, Markéta; Čépe, Klára; Tomanec, Ondřej; Zbořil, Radek

    2016-09-15

    Superparamagnetism is a phenomenon caused by quantum effects in magnetic nanomaterials. Zero-valent metals with diameters below 5 nm have been suggested as superior alternatives to superparamagnetic metal oxides, having greater superspin magnitudes and lower levels of magnetic disorder. However, synthesis of such nanometals has been hindered by their chemical instability. Here we present a method for preparing air-stable superparamagnetic iron nanoparticles trapped between thermally reduced graphene oxide nanosheets and exhibiting ring-like or core-shell morphologies depending on iron concentration. Importantly, these hybrids show superparamagnetism at room temperature and retain it even at 5 K. The corrected saturation magnetization of 185 Am(2) kg(-1) is among the highest values reported for iron-based superparamagnets. The synthetic concept is generalized exploiting functional groups of graphene oxide to stabilize and entrap cobalt, nickel and gold nanoparticles, potentially opening doors for targeted delivery, magnetic separation and imaging applications.

  16. Carbon catalysis in the aqueous oxidation of SO2 by NO2 and air

    NASA Technical Reports Server (NTRS)

    Schryer, D. R.; Schryer, J.; Cofer, W. R., III; Vay, S. A.

    1984-01-01

    Sulfur dioxide and an oxidant gas (air or NO2) were bubbled through aqueous suspensions of both washed and unwashed carbon black as well as through samples of wash water, which contained whatever soluble species were originally present on the carbon, and high-purity water. The sulfate yields obtained showed the washed and unwashed carbon to be equally catalytic for the oxidation of SO2 to sulfate by both oxidants, whereas little sulfate was generated in either the wash water or high-purity water in the absence of carbon. These results indicate that the sulfate yields produced in aqueous suspensions of the carbon studied are due to catalysis by the carbon particles rather than by soluble species dissolved from them.

  17. EMISSIONS PROCESSING FOR THE ETA/ CMAQ AIR QUALITY FORECAST SYSTEM

    EPA Science Inventory

    NOAA and EPA have created an Air Quality Forecast (AQF) system. This AQF system links an adaptation of the EPA's Community Multiscale Air Quality Model with the 12 kilometer ETA model running operationally at NOAA's National Center for Environmental Predication (NCEP). One of the...

  18. DETECTION AND MOLECULAR ANALYSIS OF PARTICULATE AIR POLLUTION INDUCED CARDIOPULMONARY OXIDATIVE STRESS USING A TRANSGENIC MOUSE MODEL AND EMERGING TECHNOLOGIES

    EPA Science Inventory


    Identification of particle characteristics and biological mechanism(s) responsible for the adverse pulmonary and cardiovascular responses associated with particulate air pollution exposure remains a critical research activity. We have employed an oxidative stress sensitive an...

  19. Flow mechanism for the long-range transport of air pollutants by the sea breeze causing inland nighttime high oxidants

    SciTech Connect

    Ueda, H.; Mitsumoto, S.; Kurita, H.

    1988-02-01

    Flow mechanism causing nightttime smog was investigated by analyzing 1) continuous records of meteorological data and concentration of oxidants (Ox) for 15 days and 2) aircraft data along the transportation route of a polluted air mass.

  20. Planar solid oxide fuel cell with staged indirect-internal air and fuel preheating and reformation

    DOEpatents

    Geisbrecht, Rodney A; Williams, Mark C

    2003-10-21

    A solid oxide fuel cell arrangement and method of use that provides internal preheating of both fuel and air in order to maintain the optimum operating temperature for the production of energy. The internal preheat passes are created by the addition of two plates, one on either side of the bipolar plate, such that these plates create additional passes through the fuel cell. This internal preheat fuel cell configuration and method reduce the requirements for external heat exchanger units and air compressors. Air or fuel may be added to the fuel cell as required to maintain the optimum operating temperature through a cathode control valve or an anode control valve, respectively. A control loop comprises a temperature sensing means within the preheat air and fuel passes, a means to compare the measured temperature to a set point temperature and a determination based on the comparison as to whether the control valves should allow additional air or fuel into the preheat or bypass manifolds of the fuel cell.

  1. Study on the process of Fe (III) oxide fluorination

    NASA Astrophysics Data System (ADS)

    Sophronov, V. L.; Kalaev, M. E.; Makaseev, Yu N.; Sachkov, V. I.; Verkhoturova, V. V.

    2016-02-01

    The article deals with a fundamentally new fluoride technology for obtaining fluoride materials, provides data on the kinetics of the process of fluorination of Fe oxide with fluorine, fluoride and ammonium bifluoride. The physical and chemical properties of obtained fluorides are shown: a study of the elemental composition, grain-size composition using the method of scanning electron microscopy and laser diffraction.

  2. Electrochemical advanced oxidation processes: today and tomorrow. A review.

    PubMed

    Sirés, Ignasi; Brillas, Enric; Oturan, Mehmet A; Rodrigo, Manuel A; Panizza, Marco

    2014-01-01

    In recent years, new advanced oxidation processes based on the electrochemical technology, the so-called electrochemical advanced oxidation processes (EAOPs), have been developed for the prevention and remediation of environmental pollution, especially focusing on water streams. These methods are based on the electrochemical generation of a very powerful oxidizing agent, such as the hydroxyl radical ((•)OH) in solution, which is then able to destroy organics up to their mineralization. EAOPs include heterogeneous processes like anodic oxidation and photoelectrocatalysis methods, in which (•)OH are generated at the anode surface either electrochemically or photochemically, and homogeneous processes like electro-Fenton, photoelectro-Fenton, and sonoelectrolysis, in which (•)OH are produced in the bulk solution. This paper presents a general overview of the application of EAOPs on the removal of aqueous organic pollutants, first reviewing the most recent works and then looking to the future. A global perspective on the fundamentals and experimental setups is offered, and laboratory-scale and pilot-scale experiments are examined and discussed.

  3. GREENING OF OXIDATION CATALYSIS THROUGH IMPROVED CATALYST AND PROCESS DESIGN

    EPA Science Inventory


    Greening of Oxidation Catalysis Through Improved Catalysts and Process Design
    Michael A. Gonzalez*, Thomas Becker, and Raymond Smith

    United State Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 W...

  4. Better End-Cap Processing for Oxidation-Resistant Polyimides

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.; Frimer, Aryeh A.

    2004-01-01

    A class of end-cap compounds that increase the thermo-oxidative stab ility of polyimides of the polymerization of monomeric reactants (PM R) type has been extended. In addition, an improved processing proto col for this class of end-cap compounds has been invented.

  5. Process and Equipment for Nitrogen Oxide Waste Conversion to Fertilizer

    NASA Technical Reports Server (NTRS)

    Lueck, Dale E. (Inventor); Parrish, Clyde F. (Inventor)

    2000-01-01

    The present invention describes a process for converting vapor streams from sources containing at least one nitrogen-containing oxidizing agent therein to a liquid fertilizer composition comprising the steps of: (1) directing a vapor stream containing at least nitrogen-containing oxidizing agent to a first contact zone; (2) contacting said vapor stream with water to form nitrogen oxide(s) from said at least one nitrogen- containing oxidizing agent; (3) directing said acid(s) as a second stream to a second contact zone; (4) exposing said second stream to hydrogen peroxide which is present within said second contact zone in a relative amount of at least 0.1% by weight of said second stream within said second contact zone to convert at least some of any nitrogen oxide species or ions other than in the nitrite form present within said second stream to nitrate ion; (5) sampling said stream within said second contact zone to determine the relative amount of hydrogen peroxide within said second contact zone; (6) adding hydrogen peroxide to said second contact zone when a level on hydrogen peroxide less than 0.1% by weight in said second stream is determined by said sampling; (7) adding a solution comprising potassium hydroxide to said second stream to maintain a pH between 6.0 and 11.0 within said second stream within said second contact zone to form a solution of potassium nitrate; and (8) removing sais solution of potassium nitrate from said second contact zone.

  6. Evaluation of advanced oxidation process for the treatment of groundwater

    SciTech Connect

    Garland, S.B. II ); Peyton, G.R. ); Rice, L.E. . Kansas City Div.)

    1990-01-01

    An advanced oxidation process utilizing ozone, ultraviolet radiation, and hydrogen peroxide was selected for the removal of chlorinated hydrocarbons, particularly trichlorethene and 1,2-dichlorethene, from groundwater underlying the US Department of Energy Kansas City Plant. Since the performance of this process for the removal of organics from groundwater is not well-documented, an evaluation was initiated to determine the performance of the treatment plant, document the operation and maintenance costs experience, and evaluate contaminant removal mechanisms. 11 refs., 3 figs.

  7. OXIDATION OF INCONEL 718 IN AIR AT TEMPERATURES FROM 973K TO 1620K.

    SciTech Connect

    GREENE,G.A.; FINFROCK,C.C.

    2000-10-01

    As part of the APT project, it was necessary to quantify the release of tungsten from the APT spallation target during postulated accident conditions in order to develop accident source terms for accident consequence characterization. Experiments with tungsten rods at high temperatures in a flowing steam environment characteristic of postulated accidents revealed that considerable vaporization of the tungsten occurred as a result of reactions with the steam and that the aerosols which formed were readily transported away from the tungsten surfaces, thus exposing fresh tungsten to react with more steam. The resulting tungsten release fractions and source terms were undesirable and it was decided to clad the tungsten target with Inconel 718 in order to protect it from contact with steam during an accident and mitigate the accident source term and the consequences. As part of the material selection criteria, experiments were conducted with Inconel 718 at high temperatures to evaluate the rate of oxidation of the proposed clad material over as wide a temperature range as possible, as well as to determine the high-temperature failure limit of the material. Samples of Inconel 718 were inserted into a preheated furnace at temperatures ranging from 973 K to 1620 K and oxidized in air for varying periods of time. After oxidizing in air at a constant temperature for the prescribed time and then being allowed to cool, the samples would be reweighed to determine their weight gain due to the uptake of oxygen. From these weight gain measurements, it was possible to identify three regimes of oxidation for Inconel 718: a low-temperature regime in which the samples became passivated after the initial oxidation, an intermediate-temperature regime in which the rate of oxidation was limited by diffusion and exhibited a constant parabolic rate dependence, and a high-temperature regime in which material deformation and damage accompanied an accelerated oxidation rate above the parabolic

  8. Processing, Structure and High Temperature Oxidation Properties of Polymer-Derived and Hafnium Oxide Based Ceramic Systems

    NASA Astrophysics Data System (ADS)

    Terauds, Kalvis

    Demands for hypersonic aircraft are driving the development of ultra-high temperature structural materials. These aircraft, envisioned to sustain Mach 5+, are expected to experience continuous temperatures of 1200--1800°C on the aircraft surface and temperatures as high as 2800°C in combustion zones. Breakthroughs in the development of fiber based ceramic matrix composites (CMCs) are opening the door to a new class of high-tech UHT structures for aerospace applications. One limitation with current carbon fiber or silicon carbide fiber based CMC technology is the inherent problem of material oxidation, requiring new approaches for protective environmental barrier coatings (EBC) in extreme environments. This thesis focuses on the development and characterization of SiCN-HfO2 based ceramic composite EBC systems to be used as a protective layer for silicon carbide fiber based CMCs. The presented work covers three main architectures for protection (i) multilayer films, (ii) polymer-derived HfSiCNO, and (iii) composite SiCN-HfO 2 infiltration. The scope of this thesis covers processing development, material characterization, and high temperature oxidation behavior of these three SiCN-HfO2 based systems. This work shows that the SiCN-HfO 2 composite materials react upon oxidation to form HfSiO4, offering a stable EBC in streaming air and water vapor at 1600°C.

  9. Treatment of oxide spent fuel using the lithium reduction process

    SciTech Connect

    Karell, E.J.; Pierce, R.D.; Mulcahey, T.P.

    1996-05-01

    The wide variety in the composition of DOE spent nuclear fuel complicates its long-term disposition because of the potential requirement to individually qualify each type of fuel for repository disposal. Argonne National Laboratory (ANL) has developed the electrometallurgical treatment technique to convert all of these spent fuel types into a single set of disposal forms, simplifying the qualification process. While metallic fuels can be directly processed using the electrometallurgical treatment technique, oxide fuels must first be reduced to the metallic form. The lithium reduction process accomplishes this pretreatment. In the lithium process the oxide components of the fuel are reduced using lithium at 650 C in the presence of molten LiCl, yielding the corresponding metals and Li{sub 2}O. The reduced metal components are then separated from the LiCl salt phase and become the feed material for electrometallurgical treatment. A demonstration test of the lithium reduction process was successfully conducted using a 10-kg batch of simulated oxide spent fuel and engineering-scale equipment specifically constructed for that purpose. This paper describes the lithium process, the equipment used in the demonstration test, and the results of the demonstration test.

  10. Effect of inlet-air humidity on the formation of oxides of nitrogen in a gas-turbine combustor

    NASA Technical Reports Server (NTRS)

    Marchionna, N. R.

    1973-01-01

    Tests were conducted to determine the effect of inlet-air humidity on the formation of oxides of nitrogen from a gas-turbine combustor. Combustor inlet-air temperature ranged from 450 F to 1050 F. The tests were run at a constant pressure of 6 atmospheres and reference Mach number of 0.065. The NO sub x emission index was found to decrease with increasing inlet-air humidity at a constant exponential rate of 19 percent per mass percent water vapor in the air. This decrease of NO sub x emission index with increasing humidity was found to be independent of inlet-air temperature.

  11. Oxidation Behavior of In-Flight Molten Aluminum Droplets in the Twin-Wire Electric Arc Thermal Spray Process

    SciTech Connect

    Donna Post Guillen; Brian G. Williams

    2005-05-01

    This paper examines the in-flight oxidation of molten aluminum sprayed in air using the twin-wire electric arc (TWEA) thermal spray process. The oxidation reaction of aluminum in air is highly exothermic and is represented by a heat generation term in the energy balance. Aerodynamic shear at the droplet surface enhances the amount of in-flight oxidation by: (1) promoting entrainment and mixing of the surface oxides within the droplet, and (2) causing a continuous heat generation effect that increases droplet temperature over that of a droplet without internal circulation. This continual source of heat input keeps the droplets in a liquid state during flight. A linear rate law based on the Mott-Cabrera theory was used to estimate the growth of the surface oxide layer formed during droplet flight. The calculated oxide volume fraction of an average droplet at impact agrees well with the experimentally determined oxide content for a typical TWEA-sprayed aluminum coating, which ranges from 3.3 to 12.7%. An explanation is provided for the elevated, nearly constant surface temperature (~ 2000 oC) of the droplets during flight to the substrate and shows that the majority of oxide content in the coating is produced during flight, rather than after deposition.

  12. Conceptual Design for the Pilot-Scale Plutonium Oxide Processing Unit in the Radiochemical Processing Laboratory

    SciTech Connect

    Lumetta, Gregg J.; Meier, David E.; Tingey, Joel M.; Casella, Amanda J.; Delegard, Calvin H.; Edwards, Matthew K.; Jones, Susan A.; Rapko, Brian M.

    2014-08-05

    This report describes a conceptual design for a pilot-scale capability to produce plutonium oxide for use as exercise and reference materials, and for use in identifying and validating nuclear forensics signatures associated with plutonium production. This capability is referred to as the Pilot-scale Plutonium oxide Processing Unit (P3U), and it will be located in the Radiochemical Processing Laboratory at the Pacific Northwest National Laboratory. The key unit operations are described, including plutonium dioxide (PuO2) dissolution, purification of the Pu by ion exchange, precipitation, and conversion to oxide by calcination.

  13. Benzene/nitrous oxide flammability in the precipitate hydrolysis process

    SciTech Connect

    Jacobs, R A

    1989-09-18

    The HAN (hydroxylamine nitrate) process for destruction of nitrite in precipitate hydrolysis produces nitrous oxide (N2O) gas as one of the products. N2O can form flammable mixtures with benzene which is also present due to radiolysis and hydrolysis of tetraphenylborate. Extensive flame modeling and explosion testing was undertaken to define the minimum oxidant for combustion of N2O/benzene using both nitrogen and carbon dioxide as diluents. The attached memorandum interprets and documents the results of the studies.

  14. Enzymatic oxidation of phenolic compounds in coffee processing wastewater.

    PubMed

    Torres, Juliana Arriel; Batista Chagas, Pricila Maria; Silva, Maria Cristina; dos Santos, Custódio Donizete; Duarte Corrêa, Angelita

    2016-01-01

    Peroxidases can be used in the treatment of wastewater containing phenolic compounds. The effluent from the wet processing of coffee fruits contains high content of these pollutants and although some studies propose treatments for this wastewater, none targets specifically the removal of these recalcitrant compounds. This study evaluates the potential use of different peroxidase sources in the oxidation of caffeic acid and of total phenolic compounds in coffee processing wastewater (CPW). The identification and quantification of phenolic compounds in CPW was performed and caffeic acid was found to be the major phenolic compound. Some factors, such as reaction time, pH, amount of H2O2 and enzyme were evaluated, in order to determine the optimum conditions for the enzyme performance for maximum oxidation of caffeic acid. The turnip peroxidase (TPE) proved efficient in the removal of caffeic acid, reaching an oxidation of 51.05% in just 15 minutes of reaction. However, in the bioremediation of the CPW, the horseradish peroxidase (HRP) was more efficient with 32.70%±0.16 of oxidation, followed by TPE with 18.25%±0.11. The treatment proposed in this work has potential as a complementary technology, since the efficiency of the existing process is intimately conditioned to the presence of these pollutants.

  15. Enzymatic oxidation of phenolic compounds in coffee processing wastewater.

    PubMed

    Torres, Juliana Arriel; Batista Chagas, Pricila Maria; Silva, Maria Cristina; dos Santos, Custódio Donizete; Duarte Corrêa, Angelita

    2016-01-01

    Peroxidases can be used in the treatment of wastewater containing phenolic compounds. The effluent from the wet processing of coffee fruits contains high content of these pollutants and although some studies propose treatments for this wastewater, none targets specifically the removal of these recalcitrant compounds. This study evaluates the potential use of different peroxidase sources in the oxidation of caffeic acid and of total phenolic compounds in coffee processing wastewater (CPW). The identification and quantification of phenolic compounds in CPW was performed and caffeic acid was found to be the major phenolic compound. Some factors, such as reaction time, pH, amount of H2O2 and enzyme were evaluated, in order to determine the optimum conditions for the enzyme performance for maximum oxidation of caffeic acid. The turnip peroxidase (TPE) proved efficient in the removal of caffeic acid, reaching an oxidation of 51.05% in just 15 minutes of reaction. However, in the bioremediation of the CPW, the horseradish peroxidase (HRP) was more efficient with 32.70%±0.16 of oxidation, followed by TPE with 18.25%±0.11. The treatment proposed in this work has potential as a complementary technology, since the efficiency of the existing process is intimately conditioned to the presence of these pollutants. PMID:26744933

  16. Impact of air pollution on oxidative DNA damage and lipid peroxidation in mothers and their newborns.

    PubMed

    Ambroz, Antonin; Vlkova, Veronika; Rossner, Pavel; Rossnerova, Andrea; Svecova, Vlasta; Milcova, Alena; Pulkrabova, Jana; Hajslova, Jana; Veleminsky, Milos; Solansky, Ivo; Sram, Radim J

    2016-08-01

    Ambient air particulate matter (PM) represents a class of heterogeneous substances that form one component of air pollution. Oxidative stress has been implicated as an important action mechanism for PM on the human organism. Oxidative damage induced by reactive oxygen species (ROS) may affect any cellular macromolecule. The aim of our study was to investigate the impact of air pollution on oxidative DNA damage [8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG)] and lipid peroxidation [15-F2t-isoprostane (15-F2t-IsoP)] in the urine and blood from mothers and newborns from two localities with different levels of air pollution: Ceske Budejovice (CB), a locality with a clean air, and Karvina, a locality with high air pollution. The samples from normal deliveries (38-41 week+) of nonsmoking mothers and their newborns were collected in the summer and winter seasons. Higher PM2.5 concentrations were found in Karvina than in CB in the summer 2013 (mean±SD: 20.41±6.28 vs. 9.45±3.62μg/m(3), P<0.001), and in the winter 2014 (mean±SD: 53.67±19.76 vs. 27.96±12.34μg/m(3), P<0.001). We observed significant differences in 15-F2t-IsoP levels between the summer and winter seasons in Karvina for newborns (mean±SD: 64.24±26.75 vs. 104.26±38.18pg/ml plasma, respectively) (P<0.001). Levels of 8-oxodG differed only in the winter season between localities, they were significantly higher (P<0.001) in newborns from Karvina in comparison with CB (mean±SD: 5.70±2.94 vs. 4.23±1.51 nmol/mmol creatinine, respectively). The results of multivariate regression analysis in newborns from Karvina showed PM2.5 concentrations to be a significant predictor for 8-oxodG excretion, PM2.5 and B[a]P (benzo[a]pyrene) concentrations to be a significant predictor for 15-F2t-IsoP levels. The results of multivariate regression analysis in mothers showed PM2.5 concentrations to be a significant predictor of 8-oxodG levels.

  17. Airway inflammation and oxidative potential of air pollutant particles in a pediatric asthma panel

    PubMed Central

    Delfino, Ralph J.; Staimer, Norbert; Tjoa, Thomas; Gillen, Daniel L.; Schauer, James J.; Shafer, Martin M.

    2014-01-01

    Airborne particulate matter (PM) components from fossil fuel combustion can induce oxidative stress initiated by reactive oxygen species (ROS). Reported associations between worsening asthma and PM2.5 mass could be related to PM oxidative potential to induce airway oxidative stress and inflammation (hallmarks of asthma pathology). We followed 45 schoolchildren with persistent asthma in their southern California homes daily over 10 days with offline fractional exhaled nitric oxide (FENO), a biomarker of airway inflammation. Ambient exposures included daily average PM2.5, PM2.5 elemental and organic carbon (EC, OC), NO2, O3, and endotoxin. We assessed PM2.5 oxidative potential using both an abiotic and an in vitro bioassay on aqueous extracts of daily particle filters: (1) dithiothreitol (DTT) assay (abiotic), representing chemically produced ROS; and (2) ROS generated intracellularly in a rat alveolar macrophage model using the fluorescent probe 2′7′-dicholorohidroflourescin diacetate. We analyzed relations of FENO to air pollutants in mixed linear regression models. FENO was significantly positively associated with lag 1-day and 2-day averages of traffic-related markers (EC, OC, and NO2), DTT and macrophage ROS, but not PM2.5 mass. DTT associations were nearly twice as strong as other exposures per interquartile range: median FENO increased 8.7–9.9% per 0.43 nmole/min/m3 DTT. Findings suggest that future research in oxidative stress-related illnesses such as asthma and PM exposure would benefit from assessments of PM oxidative potential and composition. PMID:23673461

  18. Integration between chemical oxidation and membrane thermophilic biological process.

    PubMed

    Bertanza, G; Collivignarelli, M C; Crotti, B M; Pedrazzani, R

    2010-01-01

    Full scale applications of activated sludge thermophilic aerobic process for treatment of liquid wastes are rare. This experimental work was carried out at a facility, where a thermophilic reactor (1,000 m(3) volume) is operated. In order to improve the global performance of the plant, it was decided to upgrade it, by means of two membrane filtration units (ultrafiltration -UF-, in place of the final sedimentation, and nanofiltration -NF-). Subsequently, the integration with chemical oxidation (O(3) and H(2)O(2)/UV processes) was taken into consideration. Studied solutions dealt with oxidation of both the NF effluents (permeate and concentrate). Based on experimental results and economic evaluation, an algorithm was proposed for defining limits of convenience of this process.

  19. In situ secondary organic aerosol formation from ambient pine forest air using an oxidation flow reactor

    DOE PAGES

    Palm, Brett B.; Campuzano-Jost, Pedro; Ortega, Amber M.; Day, Douglas A.; Kaser, Lisa; Jud, Werner; Karl, Thomas; Hansel, Armin; Hunter, James F.; Cross, Eben S.; et al

    2016-03-08

    An oxidation flow reactor (OFR) is a vessel inside which the concentration of a chosen oxidant can be increased for the purpose of studying SOA formation and aging by that oxidant. During the BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen–Rocky Mountain Biogenic Aerosol Study) field campaign, ambient pine forest air was oxidized by OH radicals in an OFR to measure the amount of SOA that could be formed from the real mix of ambient SOA precursor gases, and how that amount changed with time as precursors changed. High OH concentrations and short residence times allowed formore » semicontinuous cycling through a large range of OH exposures ranging from hours to weeks of equivalent (eq.) atmospheric aging. A simple model is derived and used to account for the relative timescales of condensation of low-volatility organic compounds (LVOCs) onto particles; condensational loss to the walls; and further reaction to produce volatile, non-condensing fragmentation products. More SOA production was observed in the OFR at nighttime (average 3 µg m−3 when LVOC fate corrected) compared to daytime (average 0.9 µg m−3 when LVOC fate corrected), with maximum formation observed at 0.4–1.5 eq. days of photochemical aging. SOA formation followed a similar diurnal pattern to monoterpenes, sesquiterpenes, and toluene+p-cymene concentrations, including a substantial increase just after sunrise at 07:00 local time. Higher photochemical aging (> 10 eq. days) led to a decrease in new SOA formation and a loss of preexisting OA due to heterogeneous oxidation followed by fragmentation and volatilization. When comparing two different commonly used methods of OH production in OFRs (OFR185 and OFR254-70), similar amounts of SOA formation were observed. We recommend the OFR185 mode for future forest studies. Concurrent gas-phase measurements of air after OH oxidation illustrate the decay of primary VOCs, production of

  20. In situ secondary organic aerosol formation from ambient pine forest air using an oxidation flow reactor

    NASA Astrophysics Data System (ADS)

    Palm, Brett B.; Campuzano-Jost, Pedro; Ortega, Amber M.; Day, Douglas A.; Kaser, Lisa; Jud, Werner; Karl, Thomas; Hansel, Armin; Hunter, James F.; Cross, Eben S.; Kroll, Jesse H.; Peng, Zhe; Brune, William H.; Jimenez, Jose L.

    2016-03-01

    An oxidation flow reactor (OFR) is a vessel inside which the concentration of a chosen oxidant can be increased for the purpose of studying SOA formation and aging by that oxidant. During the BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen-Rocky Mountain Biogenic Aerosol Study) field campaign, ambient pine forest air was oxidized by OH radicals in an OFR to measure the amount of SOA that could be formed from the real mix of ambient SOA precursor gases, and how that amount changed with time as precursors changed. High OH concentrations and short residence times allowed for semicontinuous cycling through a large range of OH exposures ranging from hours to weeks of equivalent (eq.) atmospheric aging. A simple model is derived and used to account for the relative timescales of condensation of low-volatility organic compounds (LVOCs) onto particles; condensational loss to the walls; and further reaction to produce volatile, non-condensing fragmentation products. More SOA production was observed in the OFR at nighttime (average 3 µg m-3 when LVOC fate corrected) compared to daytime (average 0.9 µg m-3 when LVOC fate corrected), with maximum formation observed at 0.4-1.5 eq. days of photochemical aging. SOA formation followed a similar diurnal pattern to monoterpenes, sesquiterpenes, and toluene+p-cymene concentrations, including a substantial increase just after sunrise at 07:00 local time. Higher photochemical aging (> 10 eq. days) led to a decrease in new SOA formation and a loss of preexisting OA due to heterogeneous oxidation followed by fragmentation and volatilization. When comparing two different commonly used methods of OH production in OFRs (OFR185 and OFR254-70), similar amounts of SOA formation were observed. We recommend the OFR185 mode for future forest studies. Concurrent gas-phase measurements of air after OH oxidation illustrate the decay of primary VOCs, production of small oxidized organic

  1. Oxidation resistance in LBE and air and tensile properties of ODS ferritic steels containing Al/Zr elements

    NASA Astrophysics Data System (ADS)

    Gao, R.; Xia, L. L.; Zhang, T.; Wang, X. P.; Fang, Q. F.; Liu, C. S.

    2014-12-01

    The effects of Al and Zr addition on improvement of oxidation resistance in lead-bismuth eutectic (LBE) and in air as well as the tensile properties were investigated for the oxide dispersion strengthened (ODS) steels. The 16Cr-4Al-0.8Zr-ODS steel samples were fabricated by a sol-gel method combining with spark plasma sintering technique. The tests in LBE at 600 °C for 1000 h indicate the good oxidation resistance comparing with the specimens without Zr/Al elements. The samples also exhibit superior oxidation resistance in air due to formation of dense and continuous aluminum oxide film. Minor Zr addition prevents the Al element induced coarsening of the oxide particles in ODS steels and significantly improves the ultimate tensile stress and total elongation of the samples.

  2. Development studies for a novel wet oxidation process

    SciTech Connect

    Dhooge, P.M.; Hakim, L.B.

    1994-01-01

    A catalytic wet oxidation process (DETOX), which uses an acidic iron solution to oxidize organic compounds to carbon dioxide, water, and other simple products, was investigated as a potential method for the treatment of multicomponent hazardous and mixed wastes. The organic compounds picric acid, poly(vinyl chloride), tetrachlorothiophene, pentachloropyridine, Aroclor 1260 (a polychlorinated biphenyl), and hexachlorobenzene were oxidized in 125 ml reaction vessels. The metals arsenic, barium, beryllium, cadmium, cerium (as a surrogate for plutonium), chromium, lead, mercury, neodymium (as a surrogate for uranium), nickel, and vanadium were tested in the DETOX solution. Barium, beryllium, cerium, chromium, mercury, neodymium, nickel, and vanadium were all found to be very soluble (>100 g/l) in the DETOX chloride-based solution. Arsenic, barium, cadmium, and lead solubilities were lower. Lead could be selectively precipitated from the DETOX solution. Chromium(VI) was reduced to relatively non-toxic chromium(III) by the solution. Six soils were contaminated with arsenic, barium, beryllium, chromium, lead, and neodymium oxides at approximately 0.1% by weight, and benzene, trichloroethene, mineral oil, and Aroclor 1260 at approximately 5% by weight total, and 5.g amounts treated with the DETOX solution in unstirred 125. ml reaction bombs. It is felt that soil treatment in a properly designed system is entirely possible despite incomplete oxidation of the less volatile organic materials in these unstirred tests.

  3. Impact of boron penetration on gate oxide reliability and device performance in a dual-gate oxide process

    NASA Astrophysics Data System (ADS)

    Zhang, Yunqiang; Gan, Chock H.; Li, Xi; Lee, James; Vigar, David; Sundaresan, Ravi

    2000-10-01

    The effect of boron penetration on device performance and gate oxide reliability of P+ polysilicon gate MOSFET of a dual oxide process with salicide block module was investigated. To get stable non-salicided poly sheet resistance, a capping oxide is required before source/drain RTA anneal. It is found that the transistor performance and gate oxide reliability were degraded with the capping oxide. The optimization scheme by replacing BF2 with Boron for P+ implant is demonstrated.

  4. Retrieval of the Nitrous Oxide Profiles using the AIRS Data in China

    NASA Astrophysics Data System (ADS)

    Chen, L.; Ma, P.; Tao, J.; Li, X.; Zhang, Y.; Wang, Z.; Li, S.; Xiong, X.

    2014-12-01

    As an important greenhouse gas and ozone-depleting substance, the 100-year global warming potential of Nitrous Oxide (N2O) is almost 300 times higher than that of carbon dioxide. However, there are still large uncertainties about the quantitative N2O emission and its feedback to climate change due to the coarse ground-based network. This approach attempts to retrieve the N2O profiles from the Atmospheric InfraRed Sounder (AIRS) data. First, the sensitivity of atmospheric temperature and humidity profiles and surface parameters between two spectral absorption bands were simulated by using the radiative transfer model. Second, the eigenvector regression algorithm is used to construct a priori state. Third, an optimal estimate method was developed based on the band selection of N2O. Finally, we compared our retrieved AIRS profiles with HIPPO data, and analyzed the seasonal and annual N2O distribution in China from 2004 to 2013.

  5. Crossflow air stripping and catalytic oxidation of chlorinated hydrocarbons from groundwater

    SciTech Connect

    Gavaskar, A.R.; Kim, B.C.; Rosansky, S.H.; Ong, S.K.; Marchand, E.G.

    1995-02-01

    This paper describes air stripping of chlorinated hydrocarbon contaminants from groundwater in a crossflow air stripping tower and destruction of the organic compounds by catalytic oxidation. Crossflow stripping has an advantage over conventional countercurrent stripping. In typical stripping operations, the mass transfer coefficient is insensitive to the velocity of the gas stream. The crossflow stripping tower is a geometry that increases the cross section of gas flow while making minimal disturbances to the liquid flow, allowing high gas-liquid ratios without flooding. By increasing the flow cross section for the gas stream, pressure drop (and thus fan power) can be reduced significantly. A field demonstration of the crossflow column was performed at a contaminated groundwater site. The groundwater was pumped out and sent to two 17-ft-high (5.2-m) towers in a parallel arrangement. One tower was a crossflow air stripper and the other a conventional countercurrent design. The performance of the two was compared. The key organic species targeted was dichloroethane, which has a low Henry`s law constant. Three different baffle configurations were tested in the crossflow tower. The results of this demonstration were used to develop design criteria for crossflow air strippers to be used for destruction of halogenated hydrocarbons. 4 refs., 15 figs., 2 tabs.

  6. Lanthanum manganite-based air electrode for solid oxide fuel cells

    DOEpatents

    Ruka, Roswell J.; Kuo, Lewis; Li, Baozhen

    1999-01-01

    An air electrode material for a solid oxide fuel cell is disclosed. The electrode material is based on lanthanum manganite having a perovskite-like crystal structure ABO.sub.3. The A-site of the air electrode material preferably comprises La, Ca, Ce and at least one lanthanide selected from Sm, Gd, Dy, Er, Y and Nd. The B-site of the electrode material comprises Mn with substantially no dopants. The ratio of A:B is preferably slightly above 1. A preferred air electrode composition is of the formula La.sub.w Ca.sub.x Ln.sub.y Ce.sub.z MnO.sub.3, wherein Ln comprises at least one lanthanide selected from Sm, Gd, Dy, Er, Y and Nd, w is from about 0.55 to about 0.56, x is from about 0.255 to about 0.265, y is from about 0.175 to about 0.185, and z is from about 0.005 to about 0.02. The air electrode material possesses advantageous chemical and electrical properties as well as favorable thermal expansion and thermal cycle shrinkage characteristics.

  7. Lanthanum manganite-based air electrode for solid oxide fuel cells

    DOEpatents

    Ruka, R.J.; Kuo, L.; Li, B.

    1999-06-29

    An air electrode material for a solid oxide fuel cell is disclosed. The electrode material is based on lanthanum manganite having a perovskite-like crystal structure ABO[sub 3]. The A-site of the air electrode material preferably comprises La, Ca, Ce and at least one lanthanide selected from Sm, Gd, Dy, Er, Y and Nd. The B-site of the electrode material comprises Mn with substantially no dopants. The ratio of A:B is preferably slightly above 1. A preferred air electrode composition is of the formula La[sub w]Ca[sub x]Ln[sub y]Ce[sub z]MnO[sub 3], wherein Ln comprises at least one lanthanide selected from Sm, Gd, Dy, Er, Y and Nd, w is from about 0.55 to about 0.56, x is from about 0.255 to about 0.265, y is from about 0.175 to about 0.185, and z is from about 0.005 to about 0.02. The air electrode material possesses advantageous chemical and electrical properties as well as favorable thermal expansion and thermal cycle shrinkage characteristics. 10 figs.

  8. Lewis acid catalysis and Green oxidations: sequential tandem oxidation processes induced by Mn-hyperaccumulating plants.

    PubMed

    Escande, Vincent; Renard, Brice-Loïc; Grison, Claude

    2015-04-01

    Among the phytotechnologies used for the reclamation of degraded mining sites, phytoextraction aims to diminish the concentration of polluting elements in contaminated soils. However, the biomass resulting from the phytoextraction processes (highly enriched in polluting elements) is too often considered as a problematic waste. The manganese-enriched biomass derived from native Mn-hyperaccumulating plants of New Caledonia was presented here as a valuable source of metallic elements of high interest in chemical catalysis. The preparation of the catalyst Eco-Mn1 and reagent Eco-Mn2 derived from Grevillea exul exul and Grevillea exul rubiginosa was investigated. Their unusual polymetallic compositions allowed to explore new reactivity of low oxidative state of manganese-Mn(II) for Eco-Mn1 and Mn(IV) for Eco-Mn2. Eco-Mn1 was used as a Lewis acid to catalyze the acetalization/elimination of aldehydes into enol ethers with high yields; a new green and stereoselective synthesis of (-)-isopulegol via the carbonyl-ene cyclization of (+)-citronellal was also performed with Eco-Mn1. Eco-Mn2 was used as a mild oxidative reagent and controlled the oxidation of aliphatic alcohols into aldehydes with quantitative yields. Oxidative cleavage was interestingly noticed when Eco-Mn2 was used in the presence of a polyol. Eco-Mn2 allowed direct oxidative iodination of ketones without using iodine, which is strongly discouraged by new environmental legislations. Finally, the combination of the properties in the Eco-Mn catalysts and reagents gave them an unprecedented potential to perform sequential tandem oxidation processes through new green syntheses of p-cymene from (-)-isopulegol and (+)-citronellal; and a new green synthesis of functionalized pyridines by in situ oxidation of 1,4-dihydropyridines.

  9. Lewis acid catalysis and Green oxidations: sequential tandem oxidation processes induced by Mn-hyperaccumulating plants.

    PubMed

    Escande, Vincent; Renard, Brice-Loïc; Grison, Claude

    2015-04-01

    Among the phytotechnologies used for the reclamation of degraded mining sites, phytoextraction aims to diminish the concentration of polluting elements in contaminated soils. However, the biomass resulting from the phytoextraction processes (highly enriched in polluting elements) is too often considered as a problematic waste. The manganese-enriched biomass derived from native Mn-hyperaccumulating plants of New Caledonia was presented here as a valuable source of metallic elements of high interest in chemical catalysis. The preparation of the catalyst Eco-Mn1 and reagent Eco-Mn2 derived from Grevillea exul exul and Grevillea exul rubiginosa was investigated. Their unusual polymetallic compositions allowed to explore new reactivity of low oxidative state of manganese-Mn(II) for Eco-Mn1 and Mn(IV) for Eco-Mn2. Eco-Mn1 was used as a Lewis acid to catalyze the acetalization/elimination of aldehydes into enol ethers with high yields; a new green and stereoselective synthesis of (-)-isopulegol via the carbonyl-ene cyclization of (+)-citronellal was also performed with Eco-Mn1. Eco-Mn2 was used as a mild oxidative reagent and controlled the oxidation of aliphatic alcohols into aldehydes with quantitative yields. Oxidative cleavage was interestingly noticed when Eco-Mn2 was used in the presence of a polyol. Eco-Mn2 allowed direct oxidative iodination of ketones without using iodine, which is strongly discouraged by new environmental legislations. Finally, the combination of the properties in the Eco-Mn catalysts and reagents gave them an unprecedented potential to perform sequential tandem oxidation processes through new green syntheses of p-cymene from (-)-isopulegol and (+)-citronellal; and a new green synthesis of functionalized pyridines by in situ oxidation of 1,4-dihydropyridines. PMID:25263417

  10. Formation of calcium in the products of iron oxide-aluminum thermite combustion in air

    NASA Astrophysics Data System (ADS)

    Gromov, A. A.; Gromov, A. M.; Popenko, E. M.; Sergienko, A. V.; Sabinskaya, O. G.; Raab, B.; Teipel, U.

    2016-10-01

    The composition of condensed products resulting from the combustion of thermite mixtures (Al + Fe2O3) in air is studied by precise methods. It is shown that during combustion, calcium is formed and stabilized in amounts of maximal 0.55 wt %, while is missing from reactants of 99.7 wt % purity. To explain this, it is hypothesized that a low-energy nuclear reaction takes place alongside the reactions of aluminum oxidation and nitridation, resulting in the formation of calcium (Kervran-Bolotov reaction).

  11. Carbon-catalyzed oxidation of SO2 by NO2 and air

    NASA Technical Reports Server (NTRS)

    Rogowski, R. S.; Schryer, D. R.; Cofer, W. R., III; Edahl, R. A., Jr.; Munavalli, S.

    1982-01-01

    A series of experiments was performed using carbon particles (commercial furnace black) as a surrogate for soot particles. Carbon particles were suspended in water, and gas mixtures were bubbled into the suspensions to observe the effect of carbon particles on the oxidation of SO2 by air and NO2. Identical gas mixtures were bubbled into a blank containing only pure water. After exposure each solution was analyzed for pH and sulfate. It was found that NO2 greatly enhances the oxidation of SO2 to sulfate in the presence of carbon particles. The amount of sulfate found in the blanks was significantly less. Under the conditions of these experiments no saturation of the reaction was observed and SO2 was converted to sulfate even in a highly acid medium (pH or = 1.5).

  12. Oxidation of SO2 by NO2 and air in an aqueous suspension of carbon

    NASA Technical Reports Server (NTRS)

    Rogowski, R. S.; Schryer, D. R.; Cofer, W. R., III; Edahl, R. A., Jr.; Munavalli, S.

    1982-01-01

    A series of experiments has been performed using carbon black as a surrogate for soot particles. Carbon black was suspended in water and gas mixtures were bubbled into the suspensions to observe the effect of carbon particles on the oxidation of SO2 by air and NO2. Identical gas mixtures were bubbled into a black containing only pure water. After exposure each solution was analyzed for pH and sulfate. It was found that NO2 greatly enhances the oxidation of SO2 to sulfate in the presence of carbon black. The amount of sulfate in the blanks was significantly less. Under the conditions of the experiments no saturation of the reaction was observed and SO2 was converted to sulfate even in a highly acid medium (pH not less than 1.5).

  13. Plasma Spray and Pack Cementation Process Optimization and Oxidation Behaviour of Novel Multilayered Coatings

    NASA Astrophysics Data System (ADS)

    Gao, Feng

    The hot section components in gas turbines are subjected to a harsh environment with the temperature being increased continuously. The higher temperature has directly resulted in severe oxidation of these components. Monolithic coatings such as MCrAIY and aluminide have been traditionally used to protect the components from oxidation; however, increased operating temperature quickly deteriorates the coatings due to accelerated diffusion of aluminum in the coatings. To improve the oxidation resistance a group of multilayered coatings are developed in this study. The multilayered coatings consist of a Cr-Si co-deposited layer as the diffusion barrier, a plasma sprayed NiCrA1Y coating as the middle layer and an aluminized top layer. The Cr-Si and aluminized layers are fabricated using pack cementation processes and the NiCrA1Y coatings are produced using the Mettech Axial III(TM) System. All of the coating processes are optimized using the methodology of Design of Experiments (DOE) and the results are analyzed using statistical method. The optimal processes are adopted to fabricate the multilayered coatings for oxidation tests. The coatings are exposed in air at 1050°C and 1150°C for 1000 hr. The results indicate that a Cr layer and a silicon-rich barrier layer have formed on the interface between the Cr-Si coating and the NiCrA1Y coating. This barrier layer not only prevents aluminum and chromium from diffusing into the substrate, but also impedes the diffusion of other elements from the substrate into the coating. The results also reveal that, for optimal oxidation resistance at 1050°C, the top layer in a multilayered coating should have at least Al/Ni ratio of one; whereas the multilayered coating with the All Ni ratio of two in the top layer exhibits the best oxidation resistance at 1150°C. The DOE methodology provides an excellent means for process optimization and the selection of oxidation test matrix, and also offers a more thorough understanding of the

  14. Process for growing a film epitaxially upon an oxide surface and structures formed with the process

    DOEpatents

    McKee, Rodney Allen; Walker, Frederick Joseph

    1998-01-01

    A process and structure wherein a film comprised of a perovskite or a spinel is built epitaxially upon a surface, such as an alkaline earth oxide surface, involves the epitaxial build up of alternating constituent metal oxide planes of the perovskite or spinel. The first layer of metal oxide built upon the surface includes a metal element which provides a small cation in the crystalline structure of the perovskite or spinel, and the second layer of metal oxide built upon the surface includes a metal element which provides a large cation in the crystalline structure of the perovskite or spinel. The layering sequence involved in the film build up reduces problems which would otherwise result from the interfacial electrostatics at the first atomic layers, and these oxides can be stabilized as commensurate thin films at a unit cell thickness or grown with high crystal quality to thicknesses of 0.5-0.7 .mu.m for optical device applications.

  15. Process for growing a film epitaxially upon an oxide surface and structures formed with the process

    DOEpatents

    McKee, Rodney A.; Walker, Frederick J.

    1995-01-01

    A process and structure wherein a film comprised of a perovskite or a spinel is built epitaxially upon a surface, such as an alkaline earth oxide surface, involves the epitaxial build up of alternating constituent metal oxide planes of the perovskite or spinel. The first layer of metal oxide built upon the surface includes a metal element which provides a small cation in the crystalline structure of the perovskite or spinel, and the second layer of metal oxide built upon the surface includes a metal element which provides a large cation in the crystalline structure of the perovskite or spinel. The layering sequence involved in the film build up reduces problems which would otherwise result from the interfacial electrostatics at the first atomic layers, and these oxides can be stabilized as commensurate thin films at a unit cell thickness or grown with high crystal quality to thicknesses of 0.5-0.7 .mu.m for optical device applications.

  16. Alternative materials for solid oxide fuel cells: Processing and interactions of materials

    SciTech Connect

    Bates, J.L.; Armstrong, T.R.; Chick, L.A.

    1993-11-01

    The purpose of this research is to develop alternative materials for solid oxide fuel cell (SOFC) interconnections and electrodes with improved electrical, thermal, and electrochemical properties. The overall approach for this research and development is to: minimize the number of cations in the electrode, electrolyte, and interconnection by developing yttrium compounds, such as Y(Ca)CrO{sub 3} as the interconnection, and Y(M{prime})MnO{sub 3} as the air electrode; develop advanced synthesis and fabrication processes for air sintering, below 1,500 C, of chromite interconnections through (1) the use of sintering aids; and (2) the synthesis of submicrometer powders; establish methods for the simultaneous processing and consolidation of air-sinterable powders; electrochemically evaluate interface reactions (in reproducible and controlled laboratory tests) for both the alternate and state-of-the-art materials and cell components developed under this program; and evaluate the chemical reactivity and interdiffusion effects that take place between the various fuel cell components: electrolyte/cathode, interconnect/cathode, and interconnect/anode. This paper describes a comprehensive study that assessed the processing of air-sinterable chromites, the sintering mechanism of chromites, and the chemical reactivity and interdiffusional effects between the interconnect, air, and fuel electrodes. Materials evaluated were La{sub 0.7}Ca{sub 0.31}CrO{sub 3}, La{sub 0.7}Ca{sub 0.29}CrO{sub 3}, (Y{sub 0.6}Ca{sub 0.4}){sub 1.05}Cr{sub 0.95}O{sub 3}, La{sub 1{minus}x}Sr{sub x}MnO{sub 3}, La{sub 1{minus}x}Ca{sub x}MnO{sub 3}, Y{sub 1{minus}x}Ca{sub x}MnO{sub 3}, and Y{sub 1{minus}x}Sr{sub x}MnO{sub 3}.

  17. Raman spectroscopy analysis of air grown oxide scale developed on pure zirconium substrate

    NASA Astrophysics Data System (ADS)

    Kurpaska, L.; Favergeon, J.; Lahoche, L.; El-Marssi, M.; Grosseau Poussard, J.-L.; Moulin, G.; Roelandt, J.-M.

    2015-11-01

    Using Raman spectroscopy technique, external and internal parts of zirconia oxide films developed at 500 °C and 600 °C on pure zirconium substrate under air at normal atmospheric pressure have been examined. Comparison of Raman peak positions of tetragonal and monoclinic zirconia phases, recorded during the oxide growth at elevated temperature, and after cooling at room temperature have been presented. Subsequently, Raman peak positions (or shifts) were interpreted in relation with the stress evolution in the growing zirconia scale, especially closed to the metal/oxide interface, where the influence of compressive stress in the oxide is the biggest. Reported results, for the first time show the presence of a continuous layer of tetragonal zirconia phase developed in the proximity of pure zirconium substrate. Based on the Raman peak positions we prove that this tetragonal layer is stabilized by the high compressive stress and sub-stoichiometry level. Presence of the tetragonal phase located in the outer part of the scale have been confirmed, yet its Raman characteristics suggest a stress-free tetragonal phase, therefore different type of stabilization mechanism. Presented study suggest that its stabilization could be related to the lattice defects introduced by highstoichiometry of zirconia or presence of heterovalent cations.

  18. ER Protein Processing Under Oxidative Stress: Implications and Prevention.

    PubMed

    Khalil, Mahmoud F; Valenzuela, Carlos; Sisniega, Daniella; Skouta, Rachid; Narayan, Mahesh

    2016-06-01

    Elevated levels of mitochondrial nitrosative stress have been associated with the pathogenesis of both Parkinson's and Alzheimer's diseases. The mechanism involves catalytic poisoning of the endoplasmic reticulum (ER)-resident oxidoreductase chaperone, protein disulfide isomerase (PDI), and the subsequent accumulation of ER-processed substrate proteins. Using a model system to mimic mitochondrial oxidative and nitrosative stress, we demonstrate a PDI-independent mechanism whereby reactive oxygen species (ROS) compromise regeneration rates of disulfide bond-containing ER-processed proteins. Under ROS-duress, the secretion-destined traffic adopts disulfide-exposed structures making the protein flux retrotranslocation biased. We also demonstrate that ROS-compromised protein maturation rates can be rescued by the polyphenol ellagic acid (EA). Our results are significant in that they reveal an additional mechanism which could promote neurodegenerative disorders. Furthermore, our data reveal that EA possesses therapeutic potential as a lead prophylactic agent against oxidative/nitrosative stress-related neurodegenerative diseases. PMID:26983927

  19. One-dimensional manganese-cobalt oxide nanofibres as bi-functional cathode catalysts for rechargeable metal-air batteries

    NASA Astrophysics Data System (ADS)

    Jung, Kyu-Nam; Hwang, Soo Min; Park, Min-Sik; Kim, Ki Jae; Kim, Jae-Geun; Dou, Shi Xue; Kim, Jung Ho; Lee, Jong-Won

    2015-01-01

    Rechargeable metal-air batteries are considered a promising energy storage solution owing to their high theoretical energy density. The major obstacles to realising this technology include the slow kinetics of oxygen reduction and evolution on the cathode (air electrode) upon battery discharging and charging, respectively. Here, we report non-precious metal oxide catalysts based on spinel-type manganese-cobalt oxide nanofibres fabricated by an electrospinning technique. The spinel oxide nanofibres exhibit high catalytic activity towards both oxygen reduction and evolution in an alkaline electrolyte. When incorporated as cathode catalysts in Zn-air batteries, the fibrous spinel oxides considerably reduce the discharge-charge voltage gaps (improve the round-trip efficiency) in comparison to the catalyst-free cathode. Moreover, the nanofibre catalysts remain stable over the course of repeated discharge-charge cycling; however, carbon corrosion in the catalyst/carbon composite cathode degrades the cycling performance of the batteries.

  20. One-dimensional manganese-cobalt oxide nanofibres as bi-functional cathode catalysts for rechargeable metal-air batteries.

    PubMed

    Jung, Kyu-Nam; Hwang, Soo Min; Park, Min-Sik; Kim, Ki Jae; Kim, Jae-Geun; Dou, Shi Xue; Kim, Jung Ho; Lee, Jong-Won

    2015-01-07

    Rechargeable metal-air batteries are considered a promising energy storage solution owing to their high theoretical energy density. The major obstacles to realising this technology include the slow kinetics of oxygen reduction and evolution on the cathode (air electrode) upon battery discharging and charging, respectively. Here, we report non-precious metal oxide catalysts based on spinel-type manganese-cobalt oxide nanofibres fabricated by an electrospinning technique. The spinel oxide nanofibres exhibit high catalytic activity towards both oxygen reduction and evolution in an alkaline electrolyte. When incorporated as cathode catalysts in Zn-air batteries, the fibrous spinel oxides considerably reduce the discharge-charge voltage gaps (improve the round-trip efficiency) in comparison to the catalyst-free cathode. Moreover, the nanofibre catalysts remain stable over the course of repeated discharge-charge cycling; however, carbon corrosion in the catalyst/carbon composite cathode degrades the cycling performance of the batteries.

  1. One-dimensional manganese-cobalt oxide nanofibres as bi-functional cathode catalysts for rechargeable metal-air batteries.

    PubMed

    Jung, Kyu-Nam; Hwang, Soo Min; Park, Min-Sik; Kim, Ki Jae; Kim, Jae-Geun; Dou, Shi Xue; Kim, Jung Ho; Lee, Jong-Won

    2015-01-01

    Rechargeable metal-air batteries are considered a promising energy storage solution owing to their high theoretical energy density. The major obstacles to realising this technology include the slow kinetics of oxygen reduction and evolution on the cathode (air electrode) upon battery discharging and charging, respectively. Here, we report non-precious metal oxide catalysts based on spinel-type manganese-cobalt oxide nanofibres fabricated by an electrospinning technique. The spinel oxide nanofibres exhibit high catalytic activity towards both oxygen reduction and evolution in an alkaline electrolyte. When incorporated as cathode catalysts in Zn-air batteries, the fibrous spinel oxides considerably reduce the discharge-charge voltage gaps (improve the round-trip efficiency) in comparison to the catalyst-free cathode. Moreover, the nanofibre catalysts remain stable over the course of repeated discharge-charge cycling; however, carbon corrosion in the catalyst/carbon composite cathode degrades the cycling performance of the batteries. PMID:25563733

  2. One-dimensional manganese-cobalt oxide nanofibres as bi-functional cathode catalysts for rechargeable metal-air batteries

    PubMed Central

    Jung, Kyu-Nam; Hwang, Soo Min; Park, Min-Sik; Kim, Ki Jae; Kim, Jae-Geun; Dou, Shi Xue; Kim, Jung Ho; Lee, Jong-Won

    2015-01-01

    Rechargeable metal-air batteries are considered a promising energy storage solution owing to their high theoretical energy density. The major obstacles to realising this technology include the slow kinetics of oxygen reduction and evolution on the cathode (air electrode) upon battery discharging and charging, respectively. Here, we report non-precious metal oxide catalysts based on spinel-type manganese-cobalt oxide nanofibres fabricated by an electrospinning technique. The spinel oxide nanofibres exhibit high catalytic activity towards both oxygen reduction and evolution in an alkaline electrolyte. When incorporated as cathode catalysts in Zn-air batteries, the fibrous spinel oxides considerably reduce the discharge-charge voltage gaps (improve the round-trip efficiency) in comparison to the catalyst-free cathode. Moreover, the nanofibre catalysts remain stable over the course of repeated discharge-charge cycling; however, carbon corrosion in the catalyst/carbon composite cathode degrades the cycling performance of the batteries. PMID:25563733

  3. Osteoconductivity and Hydrophilicity of TiO(2) Coatings on Ti Substrates Prepared by Different Oxidizing Processes.

    PubMed

    Yamamoto, Dai; Kawai, Ikki; Kuroda, Kensuke; Ichino, Ryoichi; Okido, Masazumi; Seki, Azusa

    2012-01-01

    Various techniques for forming TiO(2) coatings on Ti have been investigated for the improvement of the osteoconductivity of Ti implants. However, it is not clear how the oxidizing process affects this osteoconductivity. In this study, TiO(2) coatings were prepared using the following three processes: anodizing in 0.1 M H(3)PO(4) or 0.1 M NaOH aqueous solution; thermal oxidation at 673 K for 2 h in air; and a two-step process of anodizing followed by thermal oxidation. The oxide coatings were evaluated using SEM, XRD, and XPS. The water contact angle on the TiO(2) coatings was measured as a surface property. The osteoconductivity of these samples was evaluated by measuring the contact ratio of formed hard tissue on the implanted samples (defined as the R(B-I) value) after 14 d implantation in rats' tibias. Anatase was formed by anodizing and rutile by thermal oxidation, but the difference in the TiO(2) crystal structure did not influence the osteoconductivity. Anodized TiO(2) coatings were hydrophilic, but thermally oxidized TiO(2) coatings were less hydrophilic than anodized TiO(2) coatings because they lacked in surface OH groups. The TiO(2) coating process using anodizing without thermal oxidation gave effective improvement of the osteoconductivity of Ti samples.

  4. Process for Nitrogen Oxide Waste Conversion to Fertilizer

    NASA Technical Reports Server (NTRS)

    Lueck, Dale E. (Inventor); Parrish, Clyde F. (Inventor)

    2003-01-01

    The present invention describes a process for converting vapor streams from sources containing at least one nitrogen-containing oxidizing agent therein to a liquid fertilizer composition comprising the steps of: a) directing a vapor stream containing at least one nitrogen-containing oxidizing agent to a first contact zone; b) contacting said vapor stream with water to form nitrogen oxide(s) from said at least one nitrogen-containing oxidizing agent; c) directing said acid(s) as a second stream to a second contact zone; d) exposing said second stream to hydrogen peroxide which is present within said second contact zone in a relative amount of at least 0.1% by weight of said second stream within said second contact zone to convert at least some of any nitrogen oxide species or ions other than in the nitrate form present within said second stream to nitrate ion; e) sampling said stream within said second contact zone to determine the relative amount of hydrogen peroxide within said second contact zone; f) adding hydrogen peroxide to said second contact zone when a level of hydrogen peroxide less than 0.1 % by weight in said second stream is determined by said sampling; g) adding a solution comprising potassium hydroxide to said second stream to maintain a pH between 6.0 and 11.0 within said second stream within said second contact zone to form a solution of potassium nitrate; and h) removing said solution of potassium nitrate from said second contact zone.

  5. Laccase oxidation and removal of toxicants released during combustion processes.

    PubMed

    Prasetyo, Endry Nugroho; Semlitsch, Stefan; Nyanhongo, Gibson S; Lemmouchi, Yahia; Guebitz, Georg M

    2016-02-01

    This study reports for the first time the ability of laccases adsorbed on cellulose acetate to eliminate toxicants released during combustion processes. Laccases directly oxidized and eliminated more than 40% w/v of 14 mM of 1,4-dihydroxybenzene (hydroquinone); 2-methyl-1,4-benzenediol (methylhydroquinone); 1,4-dihydroxy-2,3,5-trimethylbenzene (trimethylhydroquinone); 3-methylphenol (m-cresol); 4-methylphenol (p-cresol); 2-methylphenol (o-cresol); 1,3-benzenediol (resorcinol); 1,2-dihydroxybenzene (catechol); 3,4-dihydroxytoluene (4-methylcatechol) and 2-naphthylamine. Further, laccase oxidized 2-naphthylamine, hydroquinone, catechol, methylhydroquinone and methylcatechol were also able to in turn mediate the elimination of >90% w/v of toxicants which are per-se non-laccase substrates such as 3-aminobiphenyl; 4-aminobiphenyl; benz[a]anthracene; 3-(1-nitrosopyrrolidin-2-yl) pyridine (NNN); formaldehyde; 4-(methyl-nitrosamino-1-(3-pyridyl)-1-butanone (NNK); 2-butenal (crotonaldehyde); nitric oxide and vinyl cyanide (acrylonitrile). These studies demonstrate the potential of laccase immobilized on solid supports to remove many structurally different toxicants released during combustion processes. This system has great potential application for in situ removal of toxicants in the manufacturing, food processing and food service industries. PMID:26408262

  6. Multiphase Processing of Isoprene Oxidation Products - Kinetic and Product Studies

    NASA Astrophysics Data System (ADS)

    Hoffmann, D.; Schoene, L.; Schindelka, J.; Herrmann, H.

    2010-12-01

    Isoprene represents a significant fraction of NMHC in the troposphere with recently estimated emission rates of 500-750 TgC yr-1 (1). Due to its enormous source strength, the fate of isoprene and its degradation products is important in atmospheric processes. Possible ascendancies of such oxidation processes are the regional ozone and secondary organic aerosol (SOA) formation. Some aspects of SOA formation from isoprene and its degradation products have already been studied by chamber studies (2,3). Aqueous phase oxidation processes which may occur after phase transfer of ‘early’ oxidation products are often neglected. But these processes provide a potentially important source for organic particle mass constituents such as carboxylic acids. The majority of existing aqueous phase modelling studies focus only on ‘later’ products such as methylglyoxal and oxalic acid. Yet, a recent field study reports much higher aqueous phase concentrations of some ‘earlier’ isoprene oxidation products including methacrolein (MACR) and methyl vinyl ketone (MVK) than expected (4). This indicates a possibly underestimated importance of multiphase chemical processes in the course of the isoprene oxidation as a source for the production of organic particle mass together with known ‘heterogeneous processes’ such as the direct condensation of low-volatility products from gas phase processes onto existing particle surfaces. In order to implement the isoprene multiphase chemistry in atmospheric models detailed kinetic and mechanistic studies are needed. Hence, the temperature dependence of MACR, MVK, methacrylic acid and acrylic acid exposed to NO3, SO4- and OH radicals in the aqueous phase was investigated. The measurements were performed using a laser-photolysis laser long path absorption technique. The analysis confirmed in all cases the much higher reactivity of the OH radical in comparison to SO4- and NO3 radicals. The temperature dependence is most distinct for NO3

  7. Empirical study of classification process for two-stage turbo air classifier in series

    NASA Astrophysics Data System (ADS)

    Yu, Yuan; Liu, Jiaxiang; Li, Gang

    2013-05-01

    The suitable process parameters for a two-stage turbo air classifier are important for obtaining the ultrafine powder that has a narrow particle-size distribution, however little has been published internationally on the classification process for the two-stage turbo air classifier in series. The influence of the process parameters of a two-stage turbo air classifier in series on classification performance is empirically studied by using aluminum oxide powders as the experimental material. The experimental results show the following: 1) When the rotor cage rotary speed of the first-stage classifier is increased from 2 300 r/min to 2 500 r/min with a constant rotor cage rotary speed of the second-stage classifier, classification precision is increased from 0.64 to 0.67. However, in this case, the final ultrafine powder yield is decreased from 79% to 74%, which means the classification precision and the final ultrafine powder yield can be regulated through adjusting the rotor cage rotary speed of the first-stage classifier. 2) When the rotor cage rotary speed of the second-stage classifier is increased from 2 500 r/min to 3 100 r/min with a constant rotor cage rotary speed of the first-stage classifier, the cut size is decreased from 13.16 μm to 8.76 μm, which means the cut size of the ultrafine powder can be regulated through adjusting the rotor cage rotary speed of the second-stage classifier. 3) When the feeding speed is increased from 35 kg/h to 50 kg/h, the "fish-hook" effect is strengthened, which makes the ultrafine powder yield decrease. 4) To weaken the "fish-hook" effect, the equalization of the two-stage wind speeds or the combination of a high first-stage wind speed with a low second-stage wind speed should be selected. This empirical study provides a criterion of process parameter configurations for a two-stage or multi-stage classifier in series, which offers a theoretical basis for practical production.

  8. Impact of Air Filter Material on Metal Oxide Semiconductor (MOS) Device Characteristics in HF Vapor Environment

    NASA Astrophysics Data System (ADS)

    Hsiao, Chih-Wen; Lou, Jen-Chung; Yeh, Ching-Fa; Hsieh, Chih-Ming; Lin, Shiuan-Jeng; Kusumi, Toshio

    2004-05-01

    Airborne molecular contamination (AMC) is becoming increasingly important as devices are scaled down to the nanometer generation. Optimum ultra low penetration air (ULPA) filter technology can eliminate AMC. In a cleanroom, however, the acid vapor generated from the cleaning process may degrade the ULPA filter, releasing AMC to the air and the surface of wafers, degrading the electrical characteristics of devices. This work proposes the new PTFE ULPA filter, which is resistant to acid vapor corrosion, to solve this problem. Experimental results demonstrate that the PTFE ULPA filter can effectively eliminate the AMC and provide a very clean cleanroom environment.

  9. Synthesis, characterization and formation process of transition metal oxide nanotubes using carbon nanofibers as templates

    SciTech Connect

    Ogihara, Hitoshi; Masahiro, Sadakane; Nodasaka, Yoshinobu; Ueda, Wataru

    2009-06-15

    Mono and binary transition metal oxide nanotubes could be synthesized by the immersion of carbon nanofiber templates into metal nitrate solutions and removal of the templates by heat treatment in air. The transition metal oxide nanotubes were composed of nano-crystallites of metal oxides. The functional groups on the carbon nanofiber templates were essential for the coating of these templates: they acted as adsorption sites for the metal nitrates, ensuring a uniform metal oxide coating. During the removal of the carbon nanofiber templates by calcination in air, the metal oxide coatings promoted the combustion reaction between the carbon nanofibers and oxygen. - Graphical abstract: Mono and binary transition metal-oxide nanotubes could be synthesized by the immersion of carbon nanofiber templates into metal nitrate solutions and removal of the templates by heat treatment in air.

  10. Thermal Behavior Study of the MoVTeNb Oxide Catalyst for Selective Oxidation Process

    SciTech Connect

    Idris, R.; Hamid, S. B. Abd.

    2009-06-01

    Several parameters involved in preparing the multi metal oxide (MMO) catalysts (Mo{sub 1}V{sub 0.3}Te{sub 0.23}Nb{sub 0.12}O{sub x}) for selective oxidation of propane to acrylic acid (AA) were investigated. These included the proper pre-calcined and calcinations atmosphere effect on the performance of the catalysts. It was found that each metal element plays a critical role to the performance of an effective catalyst and also the calcinations under a non-flow inert atmosphere. The characterization results from XRD, SEM, TG and DSC show the important differences depending on the activation procedures of the MoVTeNb oxide catalyst. The XRD analysis is used to identify the phase inventory of the MoVTeNb oxide catalysts. The structure of orthorhombic M1, M2, TeMo{sub 5}O{sub 16}, V{sub 0.95}Mo{sub 0.97}O{sub 5} and Mo{sub 5}O{sub 14} phase was investigated. The orthorhombic M1 phase is the most active and selective phase and is responsible for the major of the efficiently of the best catalyst for selective oxidation process. TGA and DTG allow the identification of the number and types, of reactions involving evaporation of small molecules from removal of ligands and water to condensation or drying processes. From all these analyses it was proven that the activation procedures would affect the performance of the MoVTeNb oxide catalyst.

  11. Application of electrochemical advanced oxidation processes to the mineralization of the herbicide diuron.

    PubMed

    Pipi, Angelo R F; Sirés, Ignasi; De Andrade, Adalgisa R; Brillas, Enric

    2014-08-01

    Here, solutions with 0.185mM of the herbicide diuron of pH 3.0 have been treated by electrochemical advanced oxidation processes (EAOPs) like electrochemical oxidation with electrogenerated H2O2 (EO-H2O2), electro-Fenton (EF) and UVA photoelectro-Fenton (PEF) or solar PEF (SPEF). Trials were performed in stirred tank reactors of 100mL and in a recirculation flow plant of 2.5L using a filter-press reactor with a Pt or boron-doped diamond (BDD) anode and an air-diffusion cathode for H2O2 electrogeneration. Oxidant hydroxyl radicals were formed from water oxidation at the anode and/or in the bulk from Fenton's reaction between added Fe(2+) and generated H2O2. In both systems, the relative oxidation ability of the EAOPs increased in the sequence EO-H2O2processes were more powerful due to the photolysis of intermediates by UV radiation. In the stirred tank reactor, the PEF treatment with BDD was the most potent method, yielding 93% mineralization after 360 min at 100 mA cm(-2). In the flow plant, the SPEF process attained a maximum mineralization of 70% at 100 mA cm(-2). Lower current densities slightly reduced the mineralization degree in SPEF, enhancing the current efficiency and dropping the energy consumption. The diuron decay always obeyed a pseudo-first-order kinetics, with a much greater apparent rate constant in EF and SPEF compared to EO-H2O2. Oxalic and oxamic acids were detected as final carboxylic acids. Ammonium and chloride ions were also released, the latter ion being partially converted into chlorate and perchlorate ions at the BDD surface.

  12. Using indium tin oxide material to implement the imaging of microwave plasma ignition process

    SciTech Connect

    Wang, Qiang; Hou, Lingyun; Zhang, Guixin Zhang, Boya; Liu, Cheng; Wang, Zhi; Huang, Jian

    2014-02-17

    In this paper, a method is introduced to get global observation of microwave plasma ignition process at high pressure. A microwave resonator was designed with an indium tin oxide coated glass at bottom. Microwave plasma ignition was implemented in methane and air mixture at 10 bars by a 2 ms-3 kW-2.45 GHz microwave pulse, and the high speed images of the ignition process were obtained. The images visually proved that microwave plasma ignition could lead to a multi-point ignition. The system may also be applied to obtain Schlieren images, which is commonly used to observe the development of flame kernel in an ignition process.

  13. Oxidation-reduction catalyst and its process of use

    NASA Technical Reports Server (NTRS)

    Jordan, Jeffrey D. (Inventor); Watkins, Anthony Neal (Inventor); Schryer, Jacqueline L. (Inventor); Oglesby, Donald M. (Inventor)

    2008-01-01

    This invention relates generally to a ruthenium stabilized oxidation-reduction catalyst useful for oxidizing carbon monoxide, and volatile organic compounds, and reducing nitrogen oxide species in oxidizing environments, substantially without the formation of toxic and volatile ruthenium oxide species upon said oxidizing environment being at high temperatures.

  14. Heat-transfer processes in air-cooled engine cylinders

    NASA Technical Reports Server (NTRS)

    Pinkel, Benjamin

    1938-01-01

    From a consideration of heat-transfer theory, semi-empirical expressions are set up for the transfer of heat from the combustion gases to the cylinder of an air-cooled engine and from the cylinder to the cooling air. Simple equations for the average head and barrel temperatures as functions of the important engine and cooling variables are obtained from these expressions. The expressions involve a few empirical constants, which may be readily determined from engine tests. Numerical values for these constants were obtained from single-cylinder engine tests for cylinders of the Pratt & Whitney 1535 and 1340-h engines. The equations provide a means of calculating the effect of the various engine and cooling variables on the cylinder temperatures and also of correlating the results of engine cooling tests. An example is given of the application of the equations to the correlation of cooling-test data obtained in flight.

  15. Modeling of membrane processes for air revitalization and water recovery

    NASA Technical Reports Server (NTRS)

    Lange, Kevin E.; Foerg, Sandra L.; Dall-Bauman, Liese A.

    1992-01-01

    Gas-separation and reverse-osmosis membrane models are being developed in conjunction with membrane testing at NASA JSC. The completed gas-separation membrane model extracts effective component permeabilities from multicomponent test data, and predicts the effects of flow configuration, operating conditions, and membrane dimensions on module performance. Variable feed- and permeate-side pressures are considered. The model has been applied to test data for hollow-fiber membrane modules with simulated cabin-air feeds. Results are presented for a membrane designed for air drying applications. Extracted permeabilities are used to predict the effect of operating conditions on water enrichment in the permeate. A first-order reverse-osmosis model has been applied to test data for spiral wound membrane modules with a simulated hygiene water feed. The model estimates an effective local component rejection coefficient under pseudosteady-state conditions. Results are used to define requirements for a detailed reverse-osmosis model.

  16. Increasing the Upper Temperature Oxidation Limit of Alumina Forming Austenitic Stainless Steels in Air with Water Vapor

    SciTech Connect

    Brady, Michael P; Unocic, Kinga A; Lance, Michael J; Santella, Michael L; Yamamoto, Yukinori; Walker, Larry R

    2011-01-01

    A family of alumina-forming austenitic (AFA) stainless steels is under development for use in aggressive oxidizing conditions from {approx}600-900 C. These alloys exhibit promising mechanical properties but oxidation resistance in air with water vapor environments is currently limited to {approx}800 C due to a transition from external protective alumina scale formation to internal oxidation of aluminum with increasing temperature. The oxidation behavior of a series of AFA alloys was systematically studied as a function of Cr, Si, Al, C, and B additions in an effort to provide a basis to increase the upper-temperature oxidation limit. Oxidation exposures were conducted in air with 10% water vapor environments from 800-1000 C, with post oxidation characterization of the 900 C exposed samples by electron probe microanalysis (EPMA), scanning and transmission electron microscopy, and photo-stimulated luminescence spectroscopy (PSLS). Increased levels of Al, C, and B additions were found to increase the upper-temperature oxidation limit in air with water vapor to between 950 and 1000 C. These findings are discussed in terms of alloy microstructure and possible gettering of hydrogen from water vapor at second phase carbide and boride precipitates.

  17. Solid oxide membrane (SOM) process for ytterbium and silicon production from their oxides

    NASA Astrophysics Data System (ADS)

    Jiang, Yihong

    The Solid oxide membrane (SOM) electrolysis is an innovative green technology that produces technologically important metals directly from their respective oxides. A yttria-stabilized zirconia (YSZ) tube, closed at one end is employed to separate the molten salt containing dissolved metal oxides from the anode inside the YSZ tube. When the applied electric potential between the cathode in the molten salt and the anode exceeds the dissociation potential of the desired metal oxides, oxygen ions in the molten salt migrate through the YSZ membrane and are oxidized at the anode while the dissolved metal cations in the flux are reduced to the desired metal at the cathode. Compared with existing metal production processes, the SOM process has many advantages such as one unit operation, less energy consumption, lower capital costs and zero carbon emission. Successful implementation of the SOM electrolysis process would provide a way to mitigate the negative environmental impact of the metal industry. Successful demonstration of producing ytterbium (Yb) and silicon (Si) directly from their respective oxides utilizing the SOM electrolysis process is presented in this dissertation. During the SOM electrolysis process, Yb2O3 was reduced to Yb metal on an inert cathode. The melting point of the supporting electrolyte (LiF-YbF3-Yb2O3) was determined by differential thermal analysis (DTA). Static stability testing confirmed that the YSZ tube was stable with the flux at operating temperature. Yb metal deposit on the cathode was confirmed by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). During the SOM electrolysis process for silicon production, a fluoride based flux based on BaF2, MgF2, and YF3 was engineered to serve as the liquid electrolyte for dissolving silicon dioxide. YSZ tube was used to separate the molten salt from an anode current collector in the liquid silver. Liquid tin was chosen as cathode to dissolve the reduced silicon during

  18. Vacuum-arc chromium-based coatings for protection of zirconium alloys from the high-temperature oxidation in air

    NASA Astrophysics Data System (ADS)

    Kuprin, A. S.; Belous, V. A.; Voyevodin, V. N.; Bryk, V. V.; Vasilenko, R. L.; Ovcharenko, V. D.; Reshetnyak, E. N.; Tolmachova, G. N.; V'yugov, P. N.

    2015-10-01

    Multilayer Cr-Zr/Cr/Cr-N coatings for protection of zirconium alloys from the high-temperature oxidation in air have been obtained by the vacuum-arc evaporation technique with application of filters for plasma cleaning from macroparticles. The effect of the coatings on the corrosion resistance of zirconium alloys at test temperatures between 660 and 1100 °C for 3600 s has been investigated. The thickness, structure, phase composition, mechanical properties of the coatings and oxide layers before and after oxidation tests were examined by scanning electron microscopy, X-ray diffraction analysis and nanoindentation technique. It is shown that the hard multilayer coating effectively protects zirconium from the oxidation in air for 1 h at test temperatures. As a result of the oxidation in the coating the CrO and Cr2O3 oxides are formed which reduce the oxygen penetration through the coating. At maximum test temperature of 1100 °C the oxide layer thickness in the coating is about 5 μm. The tube shape remains unchanged independent of alloy type. It has been found that uncoated zirconium oxidizes rapidly throughout the temperature range under study. At 1100 °C a porous monoclinic ZrO2 oxide layer of ≥120 μm is formed that leads to the deformation of the samples, cracking and spalling of the oxide layer.

  19. The first commercial supercritical water oxidation sludge processing plant.

    PubMed

    Griffith, James W; Raymond, Dennis H

    2002-01-01

    Final disposal of sludge continues to be one of the more pressing problems for the wastewater treatment industry. Present regulations for municipal sludge have favored beneficial use, primarily in land application. However, several agencies and entities have warned of potential health risks associated with these methods. Hydrothermal oxidation provides an alternative method that addresses the health concerns associated with sludge disposal by completely converting all organic matter in the sludge to carbon dioxide, water, and other innocuous materials. A hydrothermal oxidation system using HydroProcessing, L.L.C.'s HydroSolids process has been installed at Harlingen, Texas to process up to 9.8 dry tons per day of sludge. Based on a literature review, this system is the largest hydrothermal oxidation system in the world, and the only one built specifically to process a sludge. Start up of Unit 1 of two units of the HTO system began in April 2001. Early results have indicated COD conversion rates in excess of 99.9%. Harlingen Waterworks System estimates that the HydroSolids system will cost less than other alternatives such as autothermal thermophilic aerobic digestion and more traditional forms of digestion that still require dewatering and final disposal. The Waterworks intends to generate income from the sale of energy in the form of hot water and the use of carbon dioxide from the HydroSolids process for neutralization of high pH industrial effluent. The Waterworks also expects to generate income from the treatment of septage and grease trap wastes.

  20. Solution-Processed Indium Oxide Based Thin-Film Transistors

    NASA Astrophysics Data System (ADS)

    Xu, Wangying

    Oxide thin-film transistors (TFTs) have attracted considerable attention over the past decade due to their high carrier mobility and excellent uniformity. However, most of these oxide TFTs are usually fabricated using costly vacuum-based techniques. Recently, the solution processes have been developed due to the possibility of low-cost and large-area fabrication. In this thesis, we have carried out a detailed and systematic study of solution-processed oxide thin films and TFTs. At first, we demonstrated a passivation method to overcome the water susceptibility of solution-processed InZnO TFTs by utilizing octadecylphosphonic acid (ODPA) self-assembled monolayers (SAMs). The unpassivated InZnO TFTs exhibited large hysteresis in their electrical characteristics due to the adsorbed water at the semiconductor surface. Formation of a SAM of ODPA on the top of InZnO removed water molecules weakly absorbed at the back channel and prevented water diffusion from the surroundings. Therefore the passivated devices exhibited significantly reduced hysteretic characteristics. Secondly, we developed a simple spin-coating approach for high- k dielectrics (Al2O3, ZrO2, Y 2O3 and TiO2). These materials were used as gate dielectrics for solution-processed In2O3 or InZnO TFTs. Among the high-k dielectrics, the Al2O3-based devices showed the best performance, which is attributed to the smooth dielectric/semiconductor interface and the low interface trap density besides its good insulating property. Thirdly, the formation and properties of Al2O3 thin films under various annealing temperatures were intensively studied, revealing that the sol-gel-derived Al2O3 thin film undergoes the decomposition of organic residuals and nitrate groups, as well as conversion of aluminum hydroxides to form aluminum oxide. Besides, the Al2O 3 film was used as gate dielectric for solution-processed oxide TFTs, resulting in high mobility and low operating voltage. Finally, we proposed a green route for

  1. Final report on the oxidation of energetic materials in supercritical water. Final Air Force report

    SciTech Connect

    Buelow, S.J.; Allen, D.; Anderson, G.K.

    1995-04-03

    The objective of this project was to determine the suitability of oxidation in supercritical fluids (SCO), particularly water (SCWO), for disposal of propellants, explosives, and pyrotechnics (PEPs). The SCO studies of PEPs addressed the following issues: The efficiency of destruction of the substrate. The products of destruction contained in the effluents. Whether the process can be conducted safely on a large scale. Whether energy recovery from the process is economically practicable. The information essential for process development and equipment design was also investigated, including issues such as practical throughput of explosives through a SCWO reactor, reactor materials and corrosion, and models for process design and optimization.

  2. Processing, Microstructure, and Oxidation Behavior of Iron Foams

    NASA Astrophysics Data System (ADS)

    Park, Hyeji; Noh, Yoonsook; Choi, Hyelim; Hong, Kicheol; Kwon, Kyungjung; Choe, Heeman

    2016-09-01

    With its historically long popularity in major structural applications, the use of iron (Fe) has also recently begun to be explored as an advanced functional material. For this purpose, it is more advantageous to use Fe as a porous structure, simply because it can provide a greater surface area and a higher reaction rate. This study uses a freeze-casting method, which consists of simple and low-cost processing steps, to produce Fe foam with a mean pore size of 10 μm. We examine the influences of various parameters ( i.e., mold bottom temperature, powder content, and sintering time) on the processing of Fe foam, along with its oxidation kinetics at 823 K (550 °C) with various heat-treatment times. We confirm that Fe2O3 and Fe3O4 oxide layers are successfully formed on the surface of Fe foam. With the Fe oxide layers as an active anode material, the Fe foam can potentially be used as a three-dimensional anode current collector for an advanced lithium-ion battery.

  3. Oxidative potential and inflammatory impacts of source apportioned ambient air pollution in Beijing.

    PubMed

    Liu, Qingyang; Baumgartner, Jill; Zhang, Yuanxun; Liu, Yanju; Sun, Yongjun; Zhang, Meigen

    2014-11-01

    Air pollution exposure is associated with a range of adverse health impacts. Knowledge of the chemical components and sources of air pollution most responsible for these health effects could lead to an improved understanding of the mechanisms of such effects and more targeted risk reduction strategies. We measured daily ambient fine particulate matter (<2.5 μm in aerodynamic diameter; PM2.5) for 2 months in peri-urban and central Beijing, and assessed the contribution of its chemical components to the oxidative potential of ambient air pollution using the dithiothreitol (DTT) assay. The composition data were applied to a multivariate source apportionment model to determine the PM contributions of six sources or factors: a zinc factor, an aluminum factor, a lead point factor, a secondary source (e.g., SO4(2-), NO3(2-)), an iron source, and a soil dust source. Finally, we assessed the relationship between reactive oxygen species (ROS) activity-related PM sources and inflammatory responses in human bronchial epithelial cells. In peri-urban Beijing, the soil dust source accounted for the largest fraction (47%) of measured ROS variability. In central Beijing, a secondary source explained the greatest fraction (29%) of measured ROS variability. The ROS activities of PM collected in central Beijing were exponentially associated with in vivo inflammatory responses in epithelial cells (R2=0.65-0.89). We also observed a high correlation between three ROS-related PM sources (a lead point factor, a zinc factor, and a secondary source) and expression of an inflammatory marker (r=0.45-0.80). Our results suggest large differences in the contribution of different PM sources to ROS variability at the central versus peri-urban study sites in Beijing and that secondary sources may play an important role in PM2.5-related oxidative potential and inflammatory health impacts.

  4. Soil air carbon dioxide and nitrous oxide concentrations in profiles under tallgrass prairie and cultivation

    SciTech Connect

    Sotomayor, D.; Rice, C.W.

    1999-05-01

    Assessing the dynamics of gaseous production in soils is of interest because they are important sources and sinks of greenhouse gases. Changes in soil air carbon dioxide (CO{sub 2}) and nitrous oxide (N{sub 2}O) concentrations were studied in a Reading silt loam under prairie and cultivation. Concentrations were measured in situ over a 17-mo period to a depth of 3 m. Multilevel samples permitted collection of gases with subsequent measurement by gas chromatography in the laboratory. Soil air N{sub 2}O concentrations were near atmospheric levels for a majority of the study period in the prairie site but were significantly higher in the cultivated site. Annual mean N{sub 2}O concentrations were 0.403 and 1.09 {micro}L L{sup {minus}1} in the prairie and cultivated sites, respectively. Soil air CO{sub 2} annual mean concentrations were 1.56 {times} 10{sup 4} and 1.10 {times} 10{sup 4} {micro}L L{sup {minus}1} and ranged from 0.096 {times} 10{sup 4} to 6.45 {times} 10{sup 4} {micro}L L{sup {minus}1} and 0.087 {times} 10{sup 4} to 3.59 {times} 10{sup 4} {micro}L L{sup {minus}1} in the prairie and cultivated sites, respectively. Concentrations generally increased with depth, with maximum soil air N{sub 2}O and CO{sub 2} concentrations at 1.0 m in the prairie site and 0.5 m in the cultivated site. Nitrous oxide in the cultivated site and CO{sub 2} at both sites did not change markedly over winter months, but CO{sub 2} and N{sub 2}O concentrations reached maximums during the summer months and decreased as the year progressed. Although soil air concentrations peaked and decreased faster at shallower depths, deeper depths exhibited relative maximum concentrations for longer time periods.

  5. Interaction between graphene oxide and Pluronic F127 at the air-water interface.

    PubMed

    Li, Shanghao; Guo, Jingru; Patel, Ravi A; Dadlani, Anup L; Leblanc, Roger M

    2013-05-14

    Triblock copolymer Pluronic F127 (PF127) has previously been demonstrated to disperse graphene oxide (GO) in electrolyte solution and block the hydrophobic interaction between GO and l-tryptophan and l-tyrosine. However, the nature of this interaction between PF127 and GO remains to be characterized and elucidated. In the present study, we aimed to characterize and understand the interaction between GO and PF127 using a 2-dimensional Langmuir monolayer methodology at the air-water interface by surface pressure-area isotherm measurement, stability, adsorption, and atomic force microscopy (AFM) imaging. Based on the observation of surface pressure-area isotherms, adsorption, and stability of PF127 and PF127/GO mixture at the air-water interface, GO is suggested to change the conformation of PF127 at the air-water interface and also drag PF127 from the interface to the bulk subphase. Atomic force microscopy (AFM) image supports this assumption, as GO and PF127 can be observed by spreading the subphase solution outside the compressing barriers, as shown in the TOC graphic.

  6. The effect of various types of cement dust on sulphur dioxide oxidation in the air.

    PubMed

    Vadjić, V; Gentilizza, M; Halle, R

    1988-07-01

    The effect of various types of cement dust on the behaviour of sulphur dioxide in the air was investigated on model systems in different experimental conditions.Experiments were carried out with PC-15z-45s (Portland-blast furnace cement containing 15% blast furnace slag), PC-25p-35s (Portland-pozzolan cement containing 25% pozzolan) and EFD (electrofilter dust).EFD most effectively removed SO2 from the air stream. The next efficacious was PC-15z-45s, whereas PC-25p-35s was the least efficient. The efficacy of cement dusts for SO2 removal from the air stream depended on their chemical and granulometric composition and in particular on the size of specific surface.The rate of reaction was also influenced by experimental conditions-relative humidity, the length of contact, that is, the flow rate of gaseous mixture through the reactor, and the amount of cement dust.The experimental data show that in the contact between SO2 and cement dust catalytic oxidation of SO2 to sulphates takes place. Sulphates remain bound to the surface, from which they cannot be thermally desorbed, but can be released by extraction in the Soxhlet apparatus.

  7. Particulate matter air pollution causes oxidant-mediated increase in gut permeability in mice

    PubMed Central

    2011-01-01

    Background Exposure to particulate matter (PM) air pollution may be an important environmental factor leading to exacerbations of inflammatory illnesses in the GI tract. PM can gain access to the gastrointestinal (GI) tract via swallowing of air or secretions from the upper airways or mucociliary clearance of inhaled particles. Methods We measured PM-induced cell death and mitochondrial ROS generation in Caco-2 cells stably expressing oxidant sensitive GFP localized to mitochondria in the absence or presence of an antioxidant. C57BL/6 mice were exposed to a very high dose of urban PM from Washington, DC (200 μg/mouse) or saline via gastric gavage and small bowel and colonic tissue were harvested for histologic evaluation, and RNA isolation up to 48 hours. Permeability to 4kD dextran was measured at 48 hours. Results PM induced mitochondrial ROS generation and cell death in Caco-2 cells. PM also caused oxidant-dependent NF-κB activation, disruption of tight junctions and increased permeability of Caco-2 monolayers. Mice exposed to PM had increased intestinal permeability compared with PBS treated mice. In the small bowel, colocalization of the tight junction protein, ZO-1 was lower in the PM treated animals. In the small bowel and colon, PM exposed mice had higher levels of IL-6 mRNA and reduced levels of ZO-1 mRNA. Increased apoptosis was observed in the colon of PM exposed mice. Conclusions Exposure to high doses of urban PM causes oxidant dependent GI epithelial cell death, disruption of tight junction proteins, inflammation and increased permeability in the gut in vitro and in vivo. These PM-induced changes may contribute to exacerbations of inflammatory disorders of the gut. PMID:21658250

  8. PROCESS FOR PRODUCTION OF PLUTONIUM FROM ITS OXIDES

    DOEpatents

    Weissman, S.I.; Perlman, M.L.; Lipkin, D.

    1959-10-13

    A method is described for obtaining a carbide of plutonium and two methods for obtaining plutonium metal from its oxides. One of the latter involves heating the oxide, in particular PuO/sub 2/, to a temperature of 1200 to 1500 deg C with the stoichiometrical amount of carbon to fornn CO in a hard vacuum (3 to 10 microns Hg), the reduced and vaporized plutonium being collected on a condensing surface above the reaction crucible. When an excess of carbon is used with the PuO/sub 2/, a carbide of plutonium is formed at a crucible temperature of 1400 to 1500 deg C. The process may be halted and the carbide removed, or the reaction temperature can be increased to 1900 to 2100 deg C at the same low pressure to dissociate the carbide, in which case the plutonium is distilled out and collected on the same condensing surface.

  9. Treatment of desizing wastewater containing poly(vinyl alcohol) by wet air oxidation

    SciTech Connect

    Chen, G.; Lei, L.; Yue, P.L.; Cen, P.

    2000-05-01

    The effectiveness of wet air oxidation (WAO) is studied in a 2-L autoclave for the treatment of desizing wastewater from man-made fiber textile plants. At an oxygen pressure of less than 2 MPa, over 30-min, chemical oxygen demand (COD) removal was found to increase from 15 to 65% when the temperature was raised from 150 to 250 C. The biodegradability of the wastewater was also simultaneously increased. Up to 90% of the COD could be removed within 120 min. A simplified reaction mechanism is proposed which involves a direct mineralization step in parallel with a step in which an intermediate is formed prior to mineralization. A kinetic model for COD removal was developed based on this reaction mechanism. The model was tested with experimental COD results over the temperature range of the experiments. The dependence of the specific reaction rate constants was found to follow the Arrhenius type of equation. The direct oxidation of poly(vinyl alcohol) (PVA) to carbon dioxide and water is the dominant reaction step. The intermediates formed are not likely to be the acetic acid but may be short segments of PVA that are easily oxidized.

  10. Development studies of a novel wet oxidation process

    SciTech Connect

    Rogers, T.W.; Dooge, P.M.

    1996-12-31

    The objective of this study is to develop a novel catalytic chemical oxidation process that can be used to effectively treat multi-component wastes with a minimum of pretreatment characterization, thus providing a versatile, non-combustion method which will destroy hazardous organic compounds while simultaneously containing and concentrating toxic and radioactive metals for recovery or disposal in a readily stabilized matrix. Although the DETOX{sup SM} process had been tested to a limited extent for potential application to mixed wastes, there had not been sufficient experience with the process to determine its range of application to multicomponent waste forms. The potential applications of the process needed to be better identified. Then, the process needed to be demonstrated on wastes and remediate types on a practical scale in order that data could be obtained on application range, equipment size, capital and operating costs, effectiveness, safety, reliability, permittability, and potential commercial applications of the process. The approach for the project was, therefore, to identify the potential range of applications of the process (Phase I), to choose demonstration sites and design a demonstration prototype (Phase II), to fabricate and shakedown the demonstration unit (Phase III), then finally to demonstrate the process on surrogate hazardous and mixed wastes, and on actual mixed wastes (Phase IV).

  11. Oxidation Resistance of Materials Based on Ti3AlC2 Nanolaminate at 600 °C in Air

    NASA Astrophysics Data System (ADS)

    Ivasyshyn, Andrij; Ostash, Orest; Prikhna, Tatiana; Podhurska, Viktoriya; Basyuk, Tatiana

    2016-08-01

    The oxidation behavior of Ti3AlC2-based materials had been investigated at 600 °C in static air for 1000 h. It was shown that the intense increase of weight gain per unit surface area for sintered material with porosity of 22 % attributed to oxidation of the outer surface of the specimen and surfaces of pores in the bulk material. The oxidation kinetics of the hot-pressed Ti3AlC2-based material with 1 % porosity remarkably increased for the first 15 h and then slowly decreased. The weight gain per unit surface area for this material was 1.0 mg/cm2 after exposition for 1000 h. The intense initial oxidation of Ti3AlC2-based materials can be eliminated by pre-oxidation treatment at 1200 °C in air for 2 h. As a result, the weight gain per unit surface area for the pre-oxidized material did not exceed 0.11 mg/cm2 after 1000 h of exposition at 600 °C in air. It was demonstrated that the oxidation resistance of Ti3AlC2-based materials can be significantly improved by niobium addition.

  12. Evolution of chemically processed air parcels in the lower stratosphere

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.; Douglass, Anne R.; Schoeberl, Mark R.

    1994-01-01

    Aircraft, ground-based, and satellite measurements indicate large concentrations of ClO in the lower stratosphere in and near the polar vortex. The amount of local ozone depletion caused by these large ClO concentrations will depend on the relative rates of ozone loss and ClO recovery. ClO recovery occurs when NO(x), from HNO3 photolysis, reacts with ClO to form ClONO2. We show that air parcels with large amounts of ClO will experience a subsequent ozone depletion that depends on the solar zenith angle. When the solar zenith angle is large in the middle of winter, the recovery of the ClO concentration in the parcel is slow relative to ozone depletion. In the spring, when the solar zenith angle is smaller, the ClO recovery is much faster. After ClO recovery, the chlorine chemistry has not returned to normal. The ClO has been converted to ClONO2. ClO production from further encounters with PSCs will be limited by the heterogeneous reaction of ClONO2 with water. Large ozone depletions, of the type seen in the Antarctic, occur only if there is significant irreversible denitrification in the air parcel.

  13. Microstructure Sensitive Design and Processing in Solid Oxide Electrolyzer Cell

    SciTech Connect

    Dr. Hamid Garmestani; Dr. Stephen Herring

    2009-06-12

    The aim of this study was to develop and inexpensive manufacturing process for deposition of functionally graded thin films of LSM oxides with porosity graded microstructures for use as IT-SOFCs cathode. The spray pyrolysis method was chosen as a low-temperature processing technique for deposition of porous LSM films onto dense YXZ substrates. The effort was directed toward the optimization of the processing conditions for deposition of high quality LSM films with variety of morphologies in the range of dense to porous microstructures. Results of optimization studies of spray parameters revealed that the substrate surface temperature is the most critical parameter influencing the roughness and morphology, porosity, cracking and crystallinity of the film.

  14. Air plasma processing of poly(methyl methacrylate) micro-beads: Surface characterisations

    NASA Astrophysics Data System (ADS)

    Liu, Chaozong; Cui, Nai-Yi; Osbeck, Susan; Liang, He

    2012-10-01

    This paper reports the surface processing of poly(methyl methacrylate) (PMMA) micro-beads by using a rotary air plasma reactor, and its effects on surface properties. The surface properties, including surface wettability, surface chemistry and textures of the PMMA beads, were characterised. It was observed that the air plasma processing can improve the surface wettability of the PMMA microbeads significantly. A 15 min plasma processing can reduce the surface water contact angle of PMMA beads to about 50° from its original value of 80.3°. This was accompanied by about 8% increase in surface oxygen concentration as confirmed by XPS analysis. The optical profilometry examination revealed the air plasma processing resulted in a rougher surface that has a “delicate” surface texture. It is concluded that the surface chemistry and texture, induced by air plasma processing, co-contributed to the surface wettability improvement of PMMA micro-beads.

  15. Processing, Compatibility and Oxidation of Diboride - Oxide Matrix Composites for Ultrahigh-Temperature Applications.

    NASA Astrophysics Data System (ADS)

    Abada, Ahmed

    1990-01-01

    Promising results for the development of a ceramic/ceramic composite to be used for structural applications in the ultra high temperature range (1650-1850^ circC) have been obtained for alumina reinforced with titanium or zirconium diboribe coated with molybdenum disilicide. Prior to this achievement, several theoretical and experimental studies of particulate composites with (TiB_2 or ZrB_2) imbedded in (ZrO_2, Y_2 O_3 or Al_2 O_3) were conducted. Calculations of the compatibility and stability of oxide matrices with the diborides in vacuum showed positive energies of formation, indicating suitability of reinforcement of alumina under vacuum conditions. Also, since the sublimation of vapor species at ultra high temperatures is very critical to the stability of substances still existing in their condensed states, a detailed thermodynamic analysis of the metal -oxygen systems, was carried out using elemental data of the TiB_2, ZrB_2 , ZrO_2, Y_2 O_3, Al_2 O_3, MoSi_2 and their combinations (TiB_2 or ZrB_2)/(ZrO_2 , Y_2O_3 or Al_2O_3) for comparison, at 1650, 1850 and 2050^ circC. A comparison of the combination TiB _2 and ZrB_2 in MoSi_2/(Al_2O _3 or ZrO_2) at 1650^circC was also made. A stability analysis using equilibrium oxygen partial pressures for the TiB_2 and ZrB_2 decomposition at 1650, 1850 and 2050^ circC was carried out. A detailed characterization of the powders used for the oxide matrices, the diborides and the molybdenum disilicide are presented. The effects of the powder characteristics and the vacuum hot pressing parameters on the densification of the composites are discussed. Stability and chemical compatibility of the particulate and ternary composites in their as hot pressed states and following their vacuum and air oxidation treatments were characterized. Interdiffusion of elemental species across diboride/disilicide and oxide/disilicide interfaces was studies by EDS dot mapping. It is proposed that the growth of the Mo _5Si_3 is interface

  16. 32 CFR 806.27 - Samples of Air Force FOIA processing documents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... installation; (and/or) Processing this FOIA request will require us to collect and review a substantial number... documents might be responsive to your request. Please give us whatever additional details you may have on the Air Force records you want. Can you tell us when the records were created, and what Air...

  17. 32 CFR 806.27 - Samples of Air Force FOIA processing documents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... installation; (and/or) Processing this FOIA request will require us to collect and review a substantial number... documents might be responsive to your request. Please give us whatever additional details you may have on the Air Force records you want. Can you tell us when the records were created, and what Air...

  18. 32 CFR 806.27 - Samples of Air Force FOIA processing documents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... installation; (and/or) Processing this FOIA request will require us to collect and review a substantial number... documents might be responsive to your request. Please give us whatever additional details you may have on the Air Force records you want. Can you tell us when the records were created, and what Air...

  19. Polystyrene-poly(ethylene oxide) diblock copolymer: the effect of polystyrene and spreading concentration at the air/water interface.

    PubMed

    Glagola, Cameron P; Miceli, Lia M; Milchak, Marissa A; Halle, Emily H; Logan, Jennifer L

    2012-03-20

    Polystyrene-block-poly(ethylene oxide) (PS-PEO) is an amphiphilic diblock copolymer that undergoes microphase separation when spread at the air/water interface, forming nanosized domains. In this study, we investigate the impact of PS by examining a series of PS-PEO samples containing constant PEO (~17,000 g·mol(-1)) and variable PS (from 3600 to 200,000 g·mol(-1)) through isothermal characterization and atomic force microscopy (AFM). The polymers separated into two categories: predominantly hydrophobic and predominantly hydrophilic with a weight percent of PEO of ~20% providing the boundary between the two. AFM results indicated that predominantly hydrophilic PS-PEO forms dots while more hydrophobic samples yield a mixture of dots and spaghetti with continent-like structures appearing at ~7% PEO or less. These structures reflect a blend of polymer spreading, entanglement, and vitrification as the solvent evaporates. Changing the spreading concentration provides insight into this process with higher concentrations representing earlier kinetic stages and lower concentrations demonstrating later ones. Comparison of isothermal results and AFM analysis shows how polymer behavior at the air/water interface correlates with the observed nanostructures. Understanding the impact of polymer composition and spreading concentration is significant in leading to greater control over the nanostructures obtained through PS-PEO self-assembly and their eventual application as polymer templates.

  20. Secondary Organic Aerosol Formation from Ambient Air in an Oxidation Flow Reactor at GoAmazon2014/5

    NASA Astrophysics Data System (ADS)

    Palm, Brett B.; de Sa, Suzane S.; Campuzano-Jost, Pedro; Day, Douglas A.; Hu, Weiwei; Seco, Roger; Park, Jeong-Hoo; Guenther, Alex; Kim, Saewung; Brito, Joel; Wurm, Florian; Artaxo, Paulo; Yee, Lindsay; Isaacman-VanWertz, Gabrial; Goldstein, Allen; Newburn, Matt K.; Lizabeth Alexander, M.; Martin, Scot T.; Brune, William H.; Jimenez, Jose L.

    2016-04-01

    During GoAmazon2014/5, ambient air was exposed to controlled concentrations of OH or O3 in situ using an oxidation flow reactor (OFR). Oxidation ranged from hours-several weeks of aging. Oxidized air was sampled by several instruments (e.g., HR-AMS, ACSM, PTR-TOF-MS, SMPS, CCN) at both the T3 site (IOP1: Feb 1-Mar 31, 2014, and IOP2: Aug 15-Oct 15, 2014) and T2 site (between IOPs and into 2nd IOP). The oxidation of ambient air in the OFR led to substantial and variable secondary organic aerosol (SOA) formation from any SOA-precursor gases, known and unknown, that entered the OFR. In general, more SOA was produced during the nighttime than daytime, suggesting that SOA-precursor gases were found in relatively higher concentrations at night. Similarly, more SOA was formed in the dry season (IOP2) than wet season (IOP1). The maximum amount of SOA produced during nighttime from OH oxidation ranged from less than 1 μg/m3 on some nights to greater than 10 μg/m3 on other nights. O3 oxidation of ambient air also led to SOA formation, although several times less than from OH oxidation. The amount of SOA formation sometimes, but not always, correlated with measured gas-phase biogenic and/or anthropogenic SOA precursors (e.g., SV-TAG sesquiterpenes, PTR-TOFMS aromatics, isoprene, and monoterpenes). The SOA mass formed in the OFR from OH oxidation was up to an order of magnitude larger than could be explained from aerosol yields of measured primary VOCs. This along with measurements from previous campaigns suggests that most SOA was formed from intermediate S/IVOC sources (e.g., VOC oxidation products, evaporated POA, or direct emissions). To verify the SOA yields of VOCs under OFR experimental conditions, atmospherically-relevant concentrations of several VOCs were added individually into ambient air in the OFR and oxidized by OH or O3. SOA yields in the OFR were similar to published chamber yields. Preliminary PMF factor analysis showed production of secondary factors in

  1. Processing of Non-PFP Plutonium Oxide in Hanford Plants

    SciTech Connect

    Jones, Susan A.; Delegard, Calvin H.

    2011-03-10

    Processing of non-irradiated plutonium oxide, PuO2, scrap for recovery of plutonium values occurred routinely at Hanford’s Plutonium Finishing Plant (PFP) in glovebox line operations. Plutonium oxide is difficult to dissolve, particularly if it has been high-fired; i.e., calcined to temperatures above about 400°C and much of it was. Dissolution of the PuO2 in the scrap typically was performed in PFP’s Miscellaneous Treatment line using nitric acid (HNO3) containing some source of fluoride ion, F-, such as hydrofluoric acid (HF), sodium fluoride (NaF), or calcium fluoride (CaF2). The HNO3 concentration generally was 6 M or higher whereas the fluoride concentration was ~0.5 M or lower. At higher fluoride concentrations, plutonium fluoride (PuF4) would precipitate, thus limiting the plutonium dissolution. Some plutonium-bearing scrap also contained PuF4 and thus required no added fluoride. Once the plutonium scrap was dissolved, the excess fluoride was complexed with aluminum ion, Al3+, added as aluminum nitrate, Al(NO3)3•9H2O, to limit collateral damage to the process equipment by the corrosive fluoride. Aluminum nitrate also was added in low quantities in processing PuF4.

  2. FINAL REPORT on Experimental Validation of Stratified Flow Phenomena, Graphite Oxidation, and Mitigation Strategies of Air Ingress Accidents

    SciTech Connect

    Chang H. Oh; Eung S. Kim; Hee C. NO; Nam Z. Cho

    2011-01-01

    The U.S. Department of Energy is performing research and development that focuses on key phenomena that are important during challenging scenarios that may occur in the Next Generation Nuclear Plant (NGNP)/Generation IV very high temperature reactor (VHTR). Phenomena Identification and Ranking studies to date have identified the air ingress event, following on the heels of a VHTR depressurization, as very important. Consequently, the development of advanced air ingress-related models and verification & validation are of very high priority for the NGNP Project. Following a loss of coolant and system depressurization incident, air ingress will occur through the break, leading to oxidation of the in-core graphite structure and fuel. This study indicates that depending on the location and the size of the pipe break, the air ingress phenomena are different. In an effort to estimate the proper safety margin, experimental data and tools, including accurate multidimensional thermal-hydraulic and reactor physics models, a burn-off model, and a fracture model are required. It will also require effective strategies to mitigate the effects of oxidation, eventually. This 3-year project (FY 2008–FY 2010) is focused on various issues related to the VHTR air-ingress accident, including (a) analytical and experimental study of air ingress caused by density-driven, stratified, countercurrent flow, (b) advanced graphite oxidation experiments, (c) experimental study of burn-off in the core bottom structures, (d) structural tests of the oxidized core bottom structures, (e) implementation of advanced models developed during the previous tasks into the GAMMA code, (f) full air ingress and oxidation mitigation analyses, (g) development of core neutronic models, (h) coupling of the core neutronic and thermal hydraulic models, and (i) verification and validation of the coupled models.

  3. Unexpected toxicity to aquatic organisms of some aqueous bisphenol A samples treated by advanced oxidation processes.

    PubMed

    Tišler, Tatjana; Erjavec, Boštjan; Kaplan, Renata; Şenilă, Marin; Pintar, Albin

    2015-01-01

    In this study, photocatalytic and catalytic wet-air oxidation (CWAO) processes were used to examine removal efficiency of bisphenol A from aqueous samples over several titanate nanotube-based catalysts. Unexpected toxicity of bisphenol A (BPA) samples treated by means of the CWAO process to some tested species was determined. In addition, the CWAO effluent was recycled five- or 10-fold in order to increase the number of interactions between the liquid phase and catalyst. Consequently, the inductively coupled plasma mass spectrometry (ICP-MS) analysis indicated higher concentrations of some toxic metals like chromium, nickel, molybdenum, silver, and zinc in the recycled samples in comparison to both the single-pass sample and the photocatalytically treated solution. The highest toxicity of five- and 10-fold recycled solutions in the CWAO process was observed in water fleas, which could be correlated to high concentrations of chromium, nickel, and silver detected in tested samples. The obtained results clearly demonstrated that aqueous samples treated by means of advanced oxidation processes should always be analyzed using (i) chemical analyses to assess removal of BPA and total organic carbon from treated aqueous samples, as well as (ii) a battery of aquatic organisms from different taxonomic groups to determine possible toxicity. PMID:26114268

  4. Process for depositing epitaxial alkaline earth oxide onto a substrate and structures prepared with the process

    DOEpatents

    McKee, Rodney A.; Walker, Frederick J.

    1996-01-01

    A process and structure involving a silicon substrate utilize molecular beam epitaxy (MBE) and/or electron beam evaporation methods and an ultra-high vacuum facility to grow a layup of epitaxial alkaline earth oxide films upon the substrate surface. By selecting metal constituents for the oxides and in the appropriate proportions so that the lattice parameter of each oxide grown closely approximates that of the substrate or base layer upon which oxide is grown, lattice strain at the film/film or film/substrate interface of adjacent films is appreciably reduced or relieved. Moreover, by selecting constituents for the oxides so that the lattice parameters of the materials of adjacent oxide films either increase or decrease in size from one parameter to another parameter, a graded layup of films can be grown (with reduced strain levels therebetween) so that the outer film has a lattice parameter which closely approximates that of, and thus accomodates the epitaxial growth of, a pervoskite chosen to be grown upon the outer film.

  5. Decomposition of nitric oxide in a hot nitrogen stream to synthesize air for hypersonic wind tunnel combustion testing

    NASA Technical Reports Server (NTRS)

    Zumdieck, J. F.; Zlatarich, S. A.

    1974-01-01

    A clean source of high enthalpy air was obtained from the exothermic decomposition of nitric oxide in the presence of strongly heated nitrogen. A nitric oxide jet was introduced into a confined coaxial nitrogen stream. Measurements were made of the extent of mixing and reaction. Experimental results are compared with one- and two-dimensional chemical kinetics computations. Both analyses predict much lower reactivity than was observed experimentally. Inlet nitrogen temperatures above 2400 K were sufficient to produce experimentally a completely reacted gas stream of synthetic air.

  6. GENERATION, TRANSPORT AND DEPOSITION OF TUNGSTEN-OXIDE AEROSOLS AT 1000 C IN FLOWING AIR-STEAM MIXTURES.

    SciTech Connect

    GREENE,G.A.; FINFROCK,C.C.

    2001-10-01

    Experiments were conducted to measure the rates of oxidation and vaporization of pure tungsten rods in flowing air, steam and air-steam mixtures in laminar flow. Also measured were the downstream transport of tungsten-oxide condensation aerosols and their region of deposition, including plateout in the superheated flow tube, rainout in the condenser and ambient discharge which was collected on an array of sub-micron aerosol filters. The nominal conditions of the tests, with the exception of the first two tests, were tungsten temperatures of 1000 C, gas mixture temperatures of 200 C and wall temperatures of 150 C to 200 C. It was observed that the tungsten oxidation rates were greatest in all air and least in all steam, generally decreasing non-linearly with increasing steam mole fraction. The tungsten oxidation rates in all air were more than five times greater than the tungsten oxidation rates in all steam. The tungsten vaporization rate was zero in all air and increased with increasing steam mole fraction. The vaporization rate became maximum at a steam mole fraction of 0.85 and decreased thereafter as the steam mole fraction was increased to unity. The tungsten-oxide was transported downstream as condensation aerosols, initially flowing upwards from the tungsten rod through an 18-inch long, one-inch diameter quartz tube, around a 3.5-inch radius, 90{sup o} bend and laterally through a 24-inch horizontal run. The entire length of the quartz glass flow path was heated by electrical resistance clamshell heaters whose temperatures were individually controlled and measured. The tungsten-oxide plateout in the quartz tube was collected, nearly all of which was deposited at the end of the heated zone near the entrance to the condenser which was cold. The tungsten-oxide which rained out in the condenser as the steam condensed was collected with the condensate and weighed after being dried. The aerosol smoke which escaped the condenser was collected on the sub

  7. Oxidation rate of nuclear-grade graphite IG-110 in the kinetic regime for VHTR air ingress accident scenarios

    NASA Astrophysics Data System (ADS)

    Lee, Jo Jo; Ghosh, Tushar K.; Loyalka, Sudarshan K.

    2014-03-01

    The oxidation rates of nuclear-grade graphite IG-110 in the kinetically-controlled temperature regime of graphite oxidation were predicted and compared in Very High Temperature Reactor air ingress accident scenarios. The oxidative mass loss of graphite was measured thermogravimetrically from 873 to 1873 K in 100% air (21 mol%). The activation energy was found to be 222.07 kJ/mol, and the order of reaction with respect to oxygen concentration is 0.76. The surfaces of the samples were characterized by Scanning Electron Microscopy, Energy Dispersive Spectroscopy, Fourier Transform Infrared Spectroscopy and X-ray Photoelectron Spectroscopy before and after oxidation. These results are compared with those available in the literature, and our recently reported results for NBG-18 nuclear-grade graphite using the same technique.

  8. Combined hydrolysis acidification and bio-contact oxidation system with air-lift tubes and activated carbon bioreactor for oilfield wastewater treatment.

    PubMed

    Guo, Chunmei; Chen, Yi; Chen, Jinfu; Wang, Xiaojun; Zhang, Guangqing; Wang, Jingxiu; Cui, Wenfeng; Zhang, Zhongzhi

    2014-10-01

    This paper investigated the enhancement of the COD reduction of an oilfield wastewater treatment process by installing air-lift tubes and adding an activated carbon bioreactor (ACB) to form a combined hydrolysis acidification and bio-contact oxidation system with air-lift tubes (HA/air-lift BCO) and an ACB. Three heat-resistant bacterial strains were cultivated and subsequently applied in above pilot plant test. Installing air-lift tubes in aerobic tanks reduced the necessary air to water ratio from 20 to 5. Continuous operation of the HA/air-lift BCO system for 2 months with a hydraulic retention time of 36 h, a volumetric load of 0.14 kg COD/(m(3)d) (hydrolysis-acidification or anaerobic tank), and 0.06 kg COD/(m(3)d) (aerobic tanks) achieved an average reduction of COD by 60%, oil and grease by 62%, total suspended solids by 75%, and sulfides by 77%. With a COD load of 0.56 kg/(m(3)d), the average COD in the ACB effluent was 58 mg/L.

  9. Antioxidant and oxidative stress parameters in brain of Heteropneustes fossilis under air exposure condition; role of mitochondrial electron transport chain.

    PubMed

    Paital, Biswaranjan

    2013-09-01

    Many fishes are exposed to air in their natural habitat or during their commercial handling. In natural habitat or during commercial handling, the cat fish Heteropneustes fossilis is exposed to air for >24h. Data on its oxidative metabolism in the above condition are not available. Oxidative stress (OS) indices (lipid and protein oxidation), toxic reactive oxygen species (ROS: H2O2) generation, antioxidative status (levels of superoxide dismutase, catalase, glutathione peroxidase and reductase, ascorbic acid and non-protein sulfhydryl) and activities of electron transport chain (ETC) enzymes (complex I-IV) were investigated in brain tissue of H. fossilis under air exposure condition (0, 3, 6, 12 and 18 h at 25°C). Decreased activities of antioxidant (except catalase) and ETC enzymes (except complex II) with increased H2O2 and OS levels were observed in the tissue under water deprivation condition. Positive correlation was observed for complex II activity and non-protein thiol groups with time period of air exposure. The critical time period to induce OS and to reduce most of the studied antioxidant level in brain was found to be 3-6h air exposure. The data can be useful to minimize the stress generated during commercial handling of the live fishes those exposed to air in general and H. fossilis in particular.

  10. Evaluating Membrane Processes for Air Conditioning; Highlights in Research and Development, NREL (National Renewable Energy Laboratory)

    SciTech Connect

    2015-06-01

    This NREL Highlight discusses a recent state-of-the-art review of membrane processes for air conditioning that identifies future research opportunities. This highlight is being developed for the June 2015 S&T Alliance Board meeting.

  11. The NASA Lightning Nitrogen Oxides Model (LNOM): Application to Air Quality Modeling

    NASA Technical Reports Server (NTRS)

    Koshak, William; Peterson, Harold; Khan, Maudood; Biazar, Arastoo; Wang, Lihua

    2011-01-01

    Recent improvements to the NASA Marshall Space Flight Center Lightning Nitrogen Oxides Model (LNOM) and its application to the Community Multiscale Air Quality (CMAQ) modeling system are discussed. The LNOM analyzes Lightning Mapping Array (LMA) and National Lightning Detection Network(TradeMark)(NLDN) data to estimate the raw (i.e., unmixed and otherwise environmentally unmodified) vertical profile of lightning NO(x) (= NO + NO2). The latest LNOM estimates of lightning channel length distributions, lightning 1-m segment altitude distributions, and the vertical profile of lightning NO(x) are presented. The primary improvement to the LNOM is the inclusion of non-return stroke lightning NOx production due to: (1) hot core stepped and dart leaders, (2) stepped leader corona sheath, K-changes, continuing currents, and M-components. The impact of including LNOM-estimates of lightning NO(x) for an August 2006 run of CMAQ is discussed.

  12. Wear and friction of oxidation-resistant mechanical carbon graphites at 650 C in air

    NASA Technical Reports Server (NTRS)

    Allen, G. P.; Wisnader, D. W.

    1975-01-01

    Studies were conducted to determine the friction and wear properties of experimental carbon-graphites. Hemispherically tipped carbon-graphite rider specimens were tested in sliding contact with rotating Inconel X-750 disks in air. A surface speed of 1.33 m/sec, a load of 500 g, and a specimen temperature of 650 C were used. Results indicate: (1) hardness is not a major factor in determining friction and wear under the conditions of these studies. (2) Friction and wear as low as or lower than those observed for a good commercial seal material were attained with some of the experimental materials studied. (3) The inclusion of boron carbide (as an oxidation inhibitor) has a strong influence on wear rate. (4) Phosphate treatment reduces the friction coefficient when boron carbide is not present in the base material.

  13. Investigation of hydrogen-air ignition sensitized by nitric oxide and by nitrogen dioxide

    NASA Technical Reports Server (NTRS)

    Slack, M.; Grillo, A.

    1977-01-01

    The sensitization of stoichiometric hydrogen-air ignition by NO, NO2 and a mixture of NO and NO2 was investigated behind reflected shock waves in a shock tube. Induction times were measured in pressure range 0.27 to 2.0 atm, temperature range 800 to 1500 K, and for NO or NO2 mole percent between 0.0 and 4.5. Addition of both NO and NO2 reduced the measured induction times. The experimental data are interpreted in terms of H2-O2-NO(x) oxidation reaction mechanisms. The influence of NO(x) upon a supersonic combustion ramjet combustor test, conducted in an arc-heated facility, is assessed.

  14. Improved thermal oxidation stability of solution-processable silver nanowire transparent electrode by reduced graphene oxide.

    PubMed

    Ahn, Yumi; Jeong, Youngjun; Lee, Youngu

    2012-12-01

    Solution-processable silver nanowire-reduced graphene oxide (AgNW-rGO) hybrid transparent electrode was prepared in order to replace conventional ITO transparent electrode. AgNW-rGO hybrid transparent electrode exhibited high optical transmittance and low sheet resistance, which is comparable to ITO transparent electrode. In addition, it was found that AgNW-rGO hybrid transparent electrode exhibited highly enhanced thermal oxidation and chemical stabilities due to excellent gas-barrier property of rGO passivation layer onto AgNW film. Furthermore, the organic solar cells with AgNW-rGO hybrid transparent electrode showed good photovoltaic behavior as much as solar cells with AgNW transparent electrode. It is expected that AgNW-rGO hybrid transparent electrode can be used as a key component in various optoelectronic application such as display panels, touch screen panels, and solar cells.

  15. Improved thermal oxidation stability of solution-processable silver nanowire transparent electrode by reduced graphene oxide.

    PubMed

    Ahn, Yumi; Jeong, Youngjun; Lee, Youngu

    2012-12-01

    Solution-processable silver nanowire-reduced graphene oxide (AgNW-rGO) hybrid transparent electrode was prepared in order to replace conventional ITO transparent electrode. AgNW-rGO hybrid transparent electrode exhibited high optical transmittance and low sheet resistance, which is comparable to ITO transparent electrode. In addition, it was found that AgNW-rGO hybrid transparent electrode exhibited highly enhanced thermal oxidation and chemical stabilities due to excellent gas-barrier property of rGO passivation layer onto AgNW film. Furthermore, the organic solar cells with AgNW-rGO hybrid transparent electrode showed good photovoltaic behavior as much as solar cells with AgNW transparent electrode. It is expected that AgNW-rGO hybrid transparent electrode can be used as a key component in various optoelectronic application such as display panels, touch screen panels, and solar cells. PMID:23206541

  16. Reactive Distillation and Air Stripping Processes for Water Recycling and Trace Contaminant Control

    NASA Technical Reports Server (NTRS)

    Boul, Peter J.; Lange, Kevin E.; Conger, Bruce; Anderson, Molly

    2009-01-01

    Reactive distillation designs are considered to reduce the presence of volatile organic compounds in the purified water. Reactive distillation integrates a reactor with a distillation column. A review of the literature in this field has revealed a variety of functional reactive columns in industry. Wastewater may be purified by a combination of a reactor and a distiller (e.g., the EWRS or VPCAR concepts) or, in principle, through a design which integrates the reactor with the distiller. A review of the literature in reactive distillation has identified some different designs in such combinations of reactor and distiller. An evaluation of reactive distillation and reactive air stripping is presented with regards to the reduction of volatile organic compounds in the contaminated water and air. Among the methods presented, an architecture is presented for the evaluation of the simultaneous oxidation of organics in air and water. These and other designs are presented in light of potential improvements in power consumptions and air and water purities for architectures which include catalytic activity integrated into the water processor. In particular, catalytic oxidation of organics may be useful as a tool to remove contaminants that more traditional distillation and/or air stripping columns may not remove. A review of the current leading edge at the commercial level and at the research frontier in catalytically active materials is presented. Themes and directions from the engineering developments in catalyst design are presented conceptually in light of developments in the nanoscale chemistry of a variety of catalyst materials.

  17. Abiotic and biological mechanisms of nitric oxide removal from waste air in biotrickling filters.

    PubMed

    Chen, Jian-Meng; Ma, Jian-Feng

    2006-01-01

    Nitric oxide (NO) may participate in the ozone layer depletion and forming of nitric acid. Abiotic and biological mechanisms of NO removal from waste gases were studied in a biotrickling filter. The abiotic NO removal rate in the biotrickling filter was estimated by a review of the literature. The abiotic and biological removals were also verified in the biotrickling filter. The result has shown that chemical oxidation and bionitrification were both involved in the NO removal. It was found that the NO removal in high concentration (approximately 1000 ppm or higher) was in large measure the result of abiotic removal in both gas-phase and liquid-phase reactions. When NO concentration is low (less than approximately 100 ppm), bionitrification was the main process in the NO removal process in the biotrickling filter.

  18. 75 FR 61486 - Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Oxides...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-05

    ... Standards for Oxides of Nitrogen and Oxides of Sulfur: Second External Review Draft (75 FR 57463, September..., framing of key issues and conclusions regarding options for key elements of the standards. The four... (summary of options for elements of the nitrogen oxides (NO X ) and sulfur oxides (SO X ) standard)....

  19. Air/water oxidative desulfurization of coal and sulfur-containing compounds

    NASA Astrophysics Data System (ADS)

    Warzinski, R. P.; Freidman, S.; LaCount, R. B.

    1981-02-01

    Air/water Oxydesulfurization has been demonstrated in autoclave experiments at the Pittsburgh Energy Technology Center for various coals representative of the major U. S. coal basins. The applicability at present of this treatment for producing an environmentally acceptable coal has been restricted by recently proposed SO2 emission standards for utility boilers. The product would, however, be attractive to the many smaller industrial coal users who cannot afford to operate and maintain flue gas desulfurization systems. It is also possible that the utility industry could realize a benefit by using chemically cleaned coal with partial flue gas scrubbing. The higher cost of the cleaned coal would be offset by the reduction in capital and operating costs resulting from decreased FGD requirements. The susceptibility of sulfur in coal to oxidative removal varies with the nature of the sulfur-containing species. The inorganic sulfur compounds, primarily pyrite, marcasite, and iron sulfate, are more amenable to treatment than the organically bound sulfur which exhibits varying degrees of resistance depending on its chemical environment. Air/water Oxydesulfurization consistently removes in excess of 90 percent of the pyritic sulfur; the extent and efficiency of organic sulfur removal however, depends on the type of coal and severity of treatment used. In general, the organic sulfur of the higher rank coals exhibits more resistance to treatment than that of the lower rank coals; however, the accompanying heating value is greater for the latter. Similar treatment of sulfur-containing model compounds further illustrates the relative susceptibilities of different chemical species to oxidation. Application of these data to the understanding of the complex chemistry involved in the treatment of coal is a preliminary step toward improving the efficiency of Oxydesulfurization.

  20. Process for depositing an oxide epitaxially onto a silicon substrate and structures prepared with the process

    DOEpatents

    McKee, Rodney A.; Walker, Frederick J.

    1993-01-01

    A process and structure involving a silicon substrate utilizes an ultra high vacuum and molecular beam epitaxy (MBE) methods to grow an epitaxial oxide film upon a surface of the substrate. As the film is grown, the lattice of the compound formed at the silicon interface becomes stabilized, and a base layer comprised of an oxide having a sodium chloride-type lattice structure grows epitaxially upon the compound so as to cover the substrate surface. A perovskite may then be grown epitaxially upon the base layer to render a product which incorporates silicon, with its electronic capabilities, with a perovskite having technologically-significant properties of its own.

  1. Intrinsic catalytic properties of extruded clay honeycomb monolith toward complete oxidation of air pollutants.

    PubMed

    Assebban, Mhamed; El Kasmi, Achraf; Harti, Sanae; Chafik, Tarik

    2015-12-30

    The present work highlights the intrinsic catalytic properties of extruded clay honeycomb monolith toward complete oxidation of various air pollutants namely CO, methane, propane, acetylene, propene, n-butene, methanol, ethanol, n-propanol, n-butanol, acetone, dimethyl ether, benzene, toluene, o-xylene, monochlorobenzene and 1,2-dichlorobenzene. Total catalytic conversion was achieved for all tested compounds with different behaviors depending on pollutants' structural and chemical nature. The comparison of T50 values obtained from light-off curves allowed the establishment of the following reactivity sequence: ketone>alcohol>ether>CO>alkyne>aromatic>alkene>chlorinated aromatic>alkane. The intrinsic catalytic performances of the natural clay was ascribed to the implication of a quite complex mixture constituted by OH groups (Brønsted acids) and coordinately-unsaturated cations, such as Al(3+), Fe(3+) and Fe(2+) (Lewis acids). Hence, the combination of the clay's intrinsic catalytic performances and easier extrudability suggests a promissory potential for application in air pollution control.

  2. A new class of solid oxide metal-air redox batteries for advanced stationary energy storage

    NASA Astrophysics Data System (ADS)

    Zhao, Xuan

    Cost-effective and large-scale energy storage technologies are a key enabler of grid modernization. Among energy storage technologies currently being researched, developed and deployed, rechargeable batteries are unique and important that can offer a myriad of advantages over the conventional large scale siting- and geography- constrained pumped-hydro and compressed-air energy storage systems. However, current rechargeable batteries still need many breakthroughs in material optimization and system design to become commercially viable for stationary energy storage. This PhD research project investigates the energy storage characteristics of a new class of rechargeable solid oxide metal-air redox batteries (SOMARBs) that combines a regenerative solid oxide fuel cell (RSOFC) and hydrogen chemical-looping component. The RSOFC serves as the "electrical functioning unit", alternating between the fuel cell and electrolysis mode to realize discharge and charge cycles, respectively, while the hydrogen chemical-looping component functions as an energy storage unit (ESU), performing electrical-chemical energy conversion in situ via a H2/H2O-mediated metal/metal oxide redox reaction. One of the distinctive features of the new battery from conventional storage batteries is the ESU that is physically separated from the electrodes of RSOFC, allowing it to freely expand and contract without impacting the mechanical integrity of the entire battery structure. This feature also allows an easy switch in the chemistry of this battery. The materials selection for ESU is critical to energy capacity, round-trip efficiency and cost effectiveness of the new battery. Me-MeOx redox couples with favorable thermodynamics and kinetics are highly preferable. The preliminary theoretical analysis suggests that Fe-based redox couples can be a promising candidate for operating at both high and low temperatures. Therefore, the Fe-based redox-couple systems have been selected as the baseline for this

  3. Treatment of petroleum refinery sourwater by advanced oxidation processes.

    PubMed

    Coelho, Alessandra; Castro, Antonio V; Dezotti, Márcia; Sant'Anna, G L

    2006-09-01

    The performance of several oxidation processes to remove organic pollutants from sourwater was investigated. Sourwater is a specific stream of petroleum refineries, which contains slowly biodegradable compounds and toxic substances that impair the industrial biological wastewater treatment system. Preliminary experiments were conducted, using the following processes: H2O2, H2O2/UV, UV, photocatalysis, ozonation, Fenton and photo-Fenton. All processes, except Fenton and photo-Fenton, did not lead to satisfactory results, reducing at most 35% of the sourwater dissolved organic carbon (DOC). Thus, further experiments were performed with these two techniques to evaluate process conditions and organic matter removal kinetics. Batch experiments revealed that the Fenton reaction is very fast and reaches, in a few minutes, an ultimate DOC removal of 13-27%, due to the formation of iron complexes. Radiation for an additional period of 60 min can increase DOC removal up to 87%. Experiments were also conducted in a continuous mode, operating one 0.4L Fenton stirred reactor and one 1.6L photo-Fenton reactor in series. DOC removals above 75% were reached, when the reaction system was operated with hydraulic retention times (HRT) higher than 85 min. An empirical mathematical model was proposed to represent the DOC removal kinetics, allowing predicting process performance quite satisfactorily.

  4. Application of advanced oxidation processes for TNT removal: A review.

    PubMed

    Ayoub, Kaidar; van Hullebusch, Eric D; Cassir, Michel; Bermond, Alain

    2010-06-15

    Nowadays, there are increasingly stringent regulations requiring drastic treatment of 2,4,6-trinitrotoluene (TNT) contaminated waters to generate treated waters which could be easily reused or released into the environment without any harmful effects. TNT is among the most highly suspected explosive compounds that interfere with groundwater system due to its high toxicity and low biodegradability. The present work is an overview of the literature on TNT removal from polluted waters and soils and, more particularly, its treatability by advanced oxidation processes (AOPs). Among the remediation technologies, AOPs constitute a promising technology for the treatment of wastewaters containing non-easily biodegradable organic compounds. Data concerning the degradation of TNT reported during the period 1990-2009 are evaluated in this review. Among the AOPs, the following techniques are successively debated: processes based on hydrogen peroxide (H(2)O(2)+UV, Fenton, photo-Fenton and Fenton-like processes), photocatalysis, processes based on ozone (O(3), O(3)+UV) and electrochemical processes. Kinetic constants related to TNT degradation and the different mechanistic degradation pathways are discussed. Possible future treatment strategies, such as, coupling AOP with biological treatment is also considered as a mean to improve TNT remediation efficiency and kinetic.

  5. Producing nitric oxide by pulsed electrical discharge in air for portable inhalation therapy.

    PubMed

    Yu, Binglan; Muenster, Stefan; Blaesi, Aron H; Bloch, Donald B; Zapol, Warren M

    2015-07-01

    Inhalation of nitric oxide (NO) produces selective pulmonary vasodilation and is an effective therapy for treating pulmonary hypertension in adults and children. In the United States, the average cost of 5 days of inhaled NO for persistent pulmonary hypertension of the newborn is about $14,000. NO therapy involves gas cylinders and distribution, a complex delivery device, gas monitoring and calibration equipment, and a trained respiratory therapy staff. The objective of this study was to develop a lightweight, portable device to serve as a simple and economical method of producing pure NO from air for bedside or portable use. Two NO generators were designed and tested: an offline NO generator and an inline NO generator placed directly within the inspiratory line. Both generators use pulsed electrical discharges to produce therapeutic range NO (5 to 80 parts per million) at gas flow rates of 0.5 to 5 liters/min. NO was produced from air, as well as gas mixtures containing up to 90% O2 and 10% N2. Potentially toxic gases produced in the plasma, including nitrogen dioxide (NO2) and ozone (O3), were removed using a calcium hydroxide scavenger. An iridium spark electrode produced the lowest ratio of NO2/NO. In lambs with acute pulmonary hypertension, breathing electrically generated NO produced pulmonary vasodilation and reduced pulmonary arterial pressure and pulmonary vascular resistance index. In conclusion, electrical plasma NO generation produces therapeutic levels of NO from air. After scavenging to remove NO2 and O3 and filtration to remove particles, electrically produced NO can provide safe and effective treatment of pulmonary hypertension. PMID:26136478

  6. Producing nitric oxide by pulsed electrical discharge in air for portable inhalation therapy.

    PubMed

    Yu, Binglan; Muenster, Stefan; Blaesi, Aron H; Bloch, Donald B; Zapol, Warren M

    2015-07-01

    Inhalation of nitric oxide (NO) produces selective pulmonary vasodilation and is an effective therapy for treating pulmonary hypertension in adults and children. In the United States, the average cost of 5 days of inhaled NO for persistent pulmonary hypertension of the newborn is about $14,000. NO therapy involves gas cylinders and distribution, a complex delivery device, gas monitoring and calibration equipment, and a trained respiratory therapy staff. The objective of this study was to develop a lightweight, portable device to serve as a simple and economical method of producing pure NO from air for bedside or portable use. Two NO generators were designed and tested: an offline NO generator and an inline NO generator placed directly within the inspiratory line. Both generators use pulsed electrical discharges to produce therapeutic range NO (5 to 80 parts per million) at gas flow rates of 0.5 to 5 liters/min. NO was produced from air, as well as gas mixtures containing up to 90% O2 and 10% N2. Potentially toxic gases produced in the plasma, including nitrogen dioxide (NO2) and ozone (O3), were removed using a calcium hydroxide scavenger. An iridium spark electrode produced the lowest ratio of NO2/NO. In lambs with acute pulmonary hypertension, breathing electrically generated NO produced pulmonary vasodilation and reduced pulmonary arterial pressure and pulmonary vascular resistance index. In conclusion, electrical plasma NO generation produces therapeutic levels of NO from air. After scavenging to remove NO2 and O3 and filtration to remove particles, electrically produced NO can provide safe and effective treatment of pulmonary hypertension.

  7. Disrupted Nitric Oxide Metabolism from Type II Diabetes and Acute Exposure to Particulate Air Pollution

    PubMed Central

    Pettit, Ashley P.; Kipen, Howard; Laumbach, Robert; Ohman-Strickland, Pamela; Kelly-McNeill, Kathleen; Cepeda, Clarimel; Fan, Zhi-Hua; Amorosa, Louis; Lubitz, Sara; Schneider, Stephen; Gow, Andrew

    2015-01-01

    Type II diabetes is an established cause of vascular impairment. Particulate air pollution is known to exacerbate cardiovascular and respiratory conditions, particularly in susceptible populations. This study set out to determine the impact of exposure to traffic pollution, with and without particle filtration, on vascular endothelial function in Type II diabetes. Endothelial production of nitric oxide (NO) has previously been linked to vascular health. Reactive hyperemia induces a significant increase in plasma nitrite, the proximal metabolite of NO, in healthy subjects, while diabetics have a lower and more variable level of response. Twenty type II diabetics and 20 controls (ages 46–70 years) were taken on a 1.5hr roadway traffic air pollution exposure as passengers. We analyzed plasma nitrite, as a measure of vascular function, using forearm ischemia to elicit a reactive hyperemic response before and after exposure to one ride with and one without filtration of the particle components of pollution. Control subjects displayed a significant increase in plasma nitrite levels during reactive hyperemia. This response was no longer present following exposure to traffic air pollution, but did not vary with whether or not the particle phase was filtered out. Diabetics did not display an increase in nitrite levels following reactive hyperemia. This response was not altered following pollution exposure. These data suggest that components of acute traffic pollution exposure diminish vascular reactivity in non-diabetic individuals. It also confirms that type II diabetics have a preexisting diminished ability to appropriately respond to a vascular challenge, and that traffic pollution exposure does not cause a further measureable acute change in plasma nitrite levels in Type II diabetics. PMID:26656561

  8. Disrupted Nitric Oxide Metabolism from Type II Diabetes and Acute Exposure to Particulate Air Pollution.

    PubMed

    Pettit, Ashley P; Kipen, Howard; Laumbach, Robert; Ohman-Strickland, Pamela; Kelly-McNeill, Kathleen; Cepeda, Clarimel; Fan, Zhi-Hua; Amorosa, Louis; Lubitz, Sara; Schneider, Stephen; Gow, Andrew

    2015-01-01

    Type II diabetes is an established cause of vascular impairment. Particulate air pollution is known to exacerbate cardiovascular and respiratory conditions, particularly in susceptible populations. This study set out to determine the impact of exposure to traffic pollution, with and without particle filtration, on vascular endothelial function in Type II diabetes. Endothelial production of nitric oxide (NO) has previously been linked to vascular health. Reactive hyperemia induces a significant increase in plasma nitrite, the proximal metabolite of NO, in healthy subjects, while diabetics have a lower and more variable level of response. Twenty type II diabetics and 20 controls (ages 46-70 years) were taken on a 1.5 hr roadway traffic air pollution exposure as passengers. We analyzed plasma nitrite, as a measure of vascular function, using forearm ischemia to elicit a reactive hyperemic response before and after exposure to one ride with and one without filtration of the particle components of pollution. Control subjects displayed a significant increase in plasma nitrite levels during reactive hyperemia. This response was no longer present following exposure to traffic air pollution, but did not vary with whether or not the particle phase was filtered out. Diabetics did not display an increase in nitrite levels following reactive hyperemia. This response was not altered following pollution exposure. These data suggest that components of acute traffic pollution exposure diminish vascular reactivity in non-diabetic individuals. It also confirms that type II diabetics have a preexisting diminished ability to appropriately respond to a vascular challenge, and that traffic pollution exposure does not cause a further measureable acute change in plasma nitrite levels in Type II diabetics.

  9. Graphene oxide electrocatalyst on MnO2 air cathode as an efficient electron pump for enhanced oxygen reduction in alkaline solution

    NASA Astrophysics Data System (ADS)

    Basirun, Wan Jeffrey; Sookhakian, Mehran; Baradaran, Saeid; Endut, Zulkarnain; Mahmoudian, Mohammad Reza; Ebadi, Mehdi; Yousefi, Ramin; Ghadimi, Hanieh; Ahmed, Sohail

    2015-03-01

    Graphene oxide (GO) was deposited on the surface of a MnO2 air cathode by thermal evaporation at 50°C from a GO colloidal suspension. Fourier transformed infrared spectroscopy and field emission scanning electron microscopy confirmed the presence of GO on the MnO2 air cathode (GO-MnO2). Voltammetry and chrono-amperometry showed increased currents for the oxygen reduction reaction (ORR) in 6 M KOH solution for GO-MnO2 compared to the MnO2 cathode. The GO-MnO2 was used as an air cathode in an alkaline tin-air cell and produced a maximum power density of 13 mW cm-2, in contrast to MnO2, which produced a maximum power density of 9.2 mW cm-2. The electrochemical impedance spectroscopy results suggest that the chemical step for the ORR is the rate determining step, as proposed earlier by different researchers. It is suggested that the presence of GO and electrochemically reduced graphene oxide (ERGO) on the MnO2 surface are responsible for the increased rate of this step, whereby GO and ERGO accelerate the process of electron donation to the MnO2 and to adsorbed oxygen atoms.

  10. Graphene oxide electrocatalyst on MnO₂ air cathode as an efficient electron pump for enhanced oxygen reduction in alkaline solution.

    PubMed

    Basirun, Wan Jeffrey; Sookhakian, Mehran; Baradaran, Saeid; Endut, Zulkarnain; Mahmoudian, Mohammad Reza; Ebadi, Mehdi; Yousefi, Ramin; Ghadimi, Hanieh; Ahmed, Sohail

    2015-03-13

    Graphene oxide (GO) was deposited on the surface of a MnO2 air cathode by thermal evaporation at 50°C from a GO colloidal suspension. Fourier transformed infrared spectroscopy and field emission scanning electron microscopy confirmed the presence of GO on the MnO2 air cathode (GO-MnO2). Voltammetry and chrono-amperometry showed increased currents for the oxygen reduction reaction (ORR) in 6 M KOH solution for GO-MnO2 compared to the MnO2 cathode. The GO-MnO2 was used as an air cathode in an alkaline tin-air cell and produced a maximum power density of 13 mW cm(-2), in contrast to MnO2, which produced a maximum power density of 9.2 mW cm(-2). The electrochemical impedance spectroscopy results suggest that the chemical step for the ORR is the rate determining step, as proposed earlier by different researchers. It is suggested that the presence of GO and electrochemically reduced graphene oxide (ERGO) on the MnO2 surface are responsible for the increased rate of this step, whereby GO and ERGO accelerate the process of electron donation to the MnO2 and to adsorbed oxygen atoms.

  11. Graphene oxide electrocatalyst on MnO2 air cathode as an efficient electron pump for enhanced oxygen reduction in alkaline solution

    PubMed Central

    Basirun, Wan Jeffrey; Sookhakian, Mehran; Baradaran, Saeid; Endut, Zulkarnain; Mahmoudian, Mohammad Reza; Ebadi, Mehdi; Yousefi, Ramin; Ghadimi, Hanieh; Ahmed, Sohail

    2015-01-01

    Graphene oxide (GO) was deposited on the surface of a MnO2 air cathode by thermal evaporation at 50°C from a GO colloidal suspension. Fourier transformed infrared spectroscopy and field emission scanning electron microscopy confirmed the presence of GO on the MnO2 air cathode (GO-MnO2). Voltammetry and chrono-amperometry showed increased currents for the oxygen reduction reaction (ORR) in 6 M KOH solution for GO-MnO2 compared to the MnO2 cathode. The GO-MnO2 was used as an air cathode in an alkaline tin-air cell and produced a maximum power density of 13 mW cm−2, in contrast to MnO2, which produced a maximum power density of 9.2 mW cm−2. The electrochemical impedance spectroscopy results suggest that the chemical step for the ORR is the rate determining step, as proposed earlier by different researchers. It is suggested that the presence of GO and electrochemically reduced graphene oxide (ERGO) on the MnO2 surface are responsible for the increased rate of this step, whereby GO and ERGO accelerate the process of electron donation to the MnO2 and to adsorbed oxygen atoms. PMID:25765731

  12. The oxidation behavior of a model molybdenum/tungsten-containing alloy in air alone and in air with trace levels of NaCl(g)

    NASA Technical Reports Server (NTRS)

    Smeggil, J. G.; Bornstein, N. S.

    1983-01-01

    Thermogravimetric, metallographic, and X-ray studies of a model alloy, Ni-(17 a/o)Al-(10 a/o)Mo+W, oxidized in dry air at 600-1200 C and in air with 10 ppm NaCl gas at 900 C, are reported. The alloy was melted under Ar and pretreated in flowing H2 for 24 h at 1300 C. Polished 1.3 x 1.3 x 0.2-cm specimens were washed and degreased prior to oxidation in a quartz tube within a furnace for up to 120 hr. The oxidation activation energy of the alloy is determined to be about 30 kcal/mole. The specimens oxidized at 900 C and hotter exhibited oxidized and nitrided phases covered by complex NiMoO4, NiWO4, and NiAl2O4 scales and a porous, nonprotective outer layer of NiO. The oxidation behavior is found to be determined by the formation and growth of the scale, especially the (Mo,W)O2 component. Al2O3 scale layers were not formed, and further runs with pure O2 or Ar-(20 percent)O2 ruled out an explanation of this phenomenon based on aluminum nitride formation. The oxidation was accelerated by the addition of NaCl gas, a finding attributed to the reaction of NaCl with external locally protective Al2O3 scales and with the internal(Mo, W)O2 layers.

  13. Simultaneous constraint and phase conversion processing of oxide superconductors

    DOEpatents

    Li, Qi; Thompson, Elliott D.; Riley, Jr., Gilbert N.; Hellstrom, Eric E.; Larbalestier, David C.; DeMoranville, Kenneth L.; Parrell, Jeffrey A.; Reeves, Jodi L.

    2003-04-29

    A method of making an oxide superconductor article includes subjecting an oxide superconductor precursor to a texturing operation to orient grains of the oxide superconductor precursor to obtain a highly textured precursor; and converting the textured oxide superconducting precursor into an oxide superconductor, while simultaneously applying a force to the precursor which at least matches the expansion force experienced by the precursor during phase conversion to the oxide superconductor. The density and the degree of texture of the oxide superconductor precursor are retained during phase conversion. The constraining force may be applied isostatically.

  14. Processing of LaCrO{sub 3} for solid oxide fuel cell applications

    SciTech Connect

    Huebner, W.; Anderson, H.U.

    1994-09-01

    The University of Missouri-Rolla is performing a 5 year research program dedicated towards the development of LaCrO{sub 3}-based interconnect powders which densify when in contact with anode and cathode materials for solid oxide fuel cells (SOFC). During the course of this program the authors investigated compositions within the pseudo-ternary LaCrO{sub 3}-LaMnO{sub 3}-LaCoO{sub 3} system. Their expanded studies on the processing and sintering of LaCrO{sub 3} to make dense interconnects using LaCrO{sub 3}-based oxides at temperatures less than 1,500 C in an air atmosphere and in contact with both anode and cathode oxides. The specific objectives of this research program are to: Develop a novel technique which reproducibly yields LaCrO{sub 3}-based powders with the desired particle characteristics; Fully understand the liquid phase sintering mechanism; Clearly identify the reason why LaCrO{sub 3} does not densify in the presence of electrolyte and cathode materials; Systematically solve this problem through judicious control over the liquid phase; and Incorporate materials developed in this program into planar cells and measure their performance. Results are discussed on porosity and skrinkage, and sintering and melting behaviors.

  15. Air pollution from aircraft

    NASA Technical Reports Server (NTRS)

    Heywood, J. B.; Fay, J. A.; Chigier, N. A.

    1979-01-01

    A series of fundamental problems related to jet engine air pollution and combustion were examined. These include soot formation and oxidation, nitric oxide and carbon monoxide emissions mechanisms, pollutant dispension, flow and combustion characteristics of the NASA swirl can combustor, fuel atomization and fuel-air mixing processes, fuel spray drop velocity and size measurement, ignition and blowout. A summary of this work, and a bibliography of 41 theses and publications which describe this work, with abstracts, is included.

  16. Novel closed-loop air-stripping process for VOC removal from contaminated water. Final report

    SciTech Connect

    Bhowmick, M.; Sontag, T.K.; Semmens, M.J.

    1990-12-05

    The study presents an approach for the treatment of contaminated groundwater, which includes Volatile Organic Compounds (VOCs) stripped from the water using hollow fiber membranes or using conventional air stripping technology and then the VOCs are oxidized in the gas phase using UV oxidation or a combination of photooxidation and photo-catalysis with Titanium Dioxide (TiO2). The work on the photooxidation of VOCs is applicable to both water and soil treatment techniques, such as air stripping and in-situ vacuum extraction. The study is divided into five major segments: Each segment includes relevant sections on the experimental methods employed, the results from the tests conducted, the development of models, and the conclusions which were drawn from the work.

  17. Identification of transformation products during advanced oxidation of diatrizoate: Effect of water matrix and oxidation process.

    PubMed

    Azerrad, Sara P; Lütke Eversloh, Christian; Gilboa, Maayan; Schulz, Manoj; Ternes, Thomas; Dosoretz, Carlos G

    2016-10-15

    Removal of micropollutants from reverse osmosis (RO) brines of wastewater desalination by oxidation processes is influenced by the scavenging capacity of brines components, resulting in the accumulation of transformation products (TPs) rather than complete mineralization. In this work the iodinated contrast media diatrizoate (DTZ) was used as model compound due to its relative resistance to oxidation. Identification of TPs was performed in ultrapure water (UPW) and RO brines applying nonthermal plasma (NTP) and UVA-TiO2 as oxidation techniques. The influence of main RO brines components in the formation and accumulation of TPs, such as chloride, bicarbonate alkalinity and humic acid, was also studied during UVA-TiO2. DTZ oxidation pattern in UPW resulted similar in both UVA-TiO2 and NTP achieving 66 and 61% transformation, respectively. However, DTZ transformation in RO brines was markedly lower in UVA-TiO2 (9%) than in NTP (27%). These differences can be attributed to the synergic effect of RO brines components during NTP. Moreover, reactive species other than hydroxyl radical contributed to DTZ transformation, i.e., direct photolysis in UVA-TiO2 and direct photolysis + O3 in NTP accounted for 16 and 23%, respectively. DTZ transformation led to iodide formation in both oxidation techniques but it further oxidized to iodate by ozone in NTP. In total 14 transformation products were identified in UPW of which 3 were present only in UVA-TiO2 and 2 were present exclusively in NTP; 5 of the 14 TPs were absent in RO brines. Five of them were new and were denoted as TP-474A/B, TP-522, TP-586, TP-602, TP-628. TP-522 (mono-chlorinated) was elucidated only in presence of high chloride titer-synthetic water matrix in NTP, most probably formed by active chlorine species generated in situ. TPs accumulation in RO brines was markedly different in comparison to UPW. This denotes the influence of RO brines components in the formation of reactive species that could further attack

  18. Identification of transformation products during advanced oxidation of diatrizoate: Effect of water matrix and oxidation process.

    PubMed

    Azerrad, Sara P; Lütke Eversloh, Christian; Gilboa, Maayan; Schulz, Manoj; Ternes, Thomas; Dosoretz, Carlos G

    2016-10-15

    Removal of micropollutants from reverse osmosis (RO) brines of wastewater desalination by oxidation processes is influenced by the scavenging capacity of brines components, resulting in the accumulation of transformation products (TPs) rather than complete mineralization. In this work the iodinated contrast media diatrizoate (DTZ) was used as model compound due to its relative resistance to oxidation. Identification of TPs was performed in ultrapure water (UPW) and RO brines applying nonthermal plasma (NTP) and UVA-TiO2 as oxidation techniques. The influence of main RO brines components in the formation and accumulation of TPs, such as chloride, bicarbonate alkalinity and humic acid, was also studied during UVA-TiO2. DTZ oxidation pattern in UPW resulted similar in both UVA-TiO2 and NTP achieving 66 and 61% transformation, respectively. However, DTZ transformation in RO brines was markedly lower in UVA-TiO2 (9%) than in NTP (27%). These differences can be attributed to the synergic effect of RO brines components during NTP. Moreover, reactive species other than hydroxyl radical contributed to DTZ transformation, i.e., direct photolysis in UVA-TiO2 and direct photolysis + O3 in NTP accounted for 16 and 23%, respectively. DTZ transformation led to iodide formation in both oxidation techniques but it further oxidized to iodate by ozone in NTP. In total 14 transformation products were identified in UPW of which 3 were present only in UVA-TiO2 and 2 were present exclusively in NTP; 5 of the 14 TPs were absent in RO brines. Five of them were new and were denoted as TP-474A/B, TP-522, TP-586, TP-602, TP-628. TP-522 (mono-chlorinated) was elucidated only in presence of high chloride titer-synthetic water matrix in NTP, most probably formed by active chlorine species generated in situ. TPs accumulation in RO brines was markedly different in comparison to UPW. This denotes the influence of RO brines components in the formation of reactive species that could further attack

  19. Process for making surfactant capped metal oxide nanocrystals, and products produced by the process

    DOEpatents

    Alivisatos, A. Paul; Rockenberger, Joerg

    2006-01-10

    Disclosed is a process for making surfactant capped nanocrystals of metal oxides which are dispersable in organic solvents. The process comprises decomposing a metal cupferron complex of the formula MXCupX, wherein M is a metal, and Cup is a N-substituted N-Nitroso hydroxylamine, in the presence of a coordinating surfactant, the reaction being conducted at a temperature ranging from about 150 to about 400.degree. C., for a period of time sufficient to complete the reaction. Also disclosed are compounds made by the process.

  20. Long-term oxidation of candidate cast iron and stainless steel exhaust system alloys from 650 to 800 °C in air with water vapor

    SciTech Connect

    Brady, Michael P.; Muralidharan, Govindarajan; Leonard, Donovan .; Haynes, James A.; Weldon, R. G.; England, R. D.

    2014-08-29

    Here, the oxidation behavior of SiMo cast iron, Ni-resist D5S cast iron, cast chromia-forming austenitic stainless steels of varying Cr/Ni content based on CF8C plus, HK, and HP, and a developmental cast alumina-forming austenitic (AFA) stainless steel of interest for diesel exhaust system components were studied for up to 5000 h at 650-800 °C in air with 10% H2O. At 650 °C, the Ni-resist D5S exhibited moderately better oxidation resistance than did the SiMo cast iron. However, the D5S suffered from oxide scale spallation issues at 700 °C and higher, whereas the oxide scales formed on SiMo cast iron remained adherent from 700-800 °C despite oxide scales hundreds of microns thick. The oxidation of the SiMo cast iron exhibited unusual temperature dependence, with periods of slower oxidation kinetics at 750-800 °C compared to 650-700 °C due to continuous silica-rich scale formation at the higher temperatures. The oxidation of the cast chromia-forming austenitics trended with the level of Cr and Ni additions, with small mass losses consistent with Cr oxy-hydroxide volatilization processes for the higher 25Cr/25-35Ni HK and HP type alloys, and transition to rapid Fe-base oxide formation and scale spallation in the lower 19Cr/12Ni CF8C plus type alloy. In contrast, small positive mass changes consistent with protective alumina scale formation were observed for the cast AFA alloy under all conditions studied. Implications of these findings for diesel exhaust system components are discussed.

  1. Long-term oxidation of candidate cast iron and stainless steel exhaust system alloys from 650 to 800 °C in air with water vapor

    DOE PAGES

    Brady, Michael P.; Muralidharan, Govindarajan; Leonard, Donovan .; Haynes, James A.; Weldon, R. G.; England, R. D.

    2014-08-29

    Here, the oxidation behavior of SiMo cast iron, Ni-resist D5S cast iron, cast chromia-forming austenitic stainless steels of varying Cr/Ni content based on CF8C plus, HK, and HP, and a developmental cast alumina-forming austenitic (AFA) stainless steel of interest for diesel exhaust system components were studied for up to 5000 h at 650-800 °C in air with 10% H2O. At 650 °C, the Ni-resist D5S exhibited moderately better oxidation resistance than did the SiMo cast iron. However, the D5S suffered from oxide scale spallation issues at 700 °C and higher, whereas the oxide scales formed on SiMo cast iron remainedmore » adherent from 700-800 °C despite oxide scales hundreds of microns thick. The oxidation of the SiMo cast iron exhibited unusual temperature dependence, with periods of slower oxidation kinetics at 750-800 °C compared to 650-700 °C due to continuous silica-rich scale formation at the higher temperatures. The oxidation of the cast chromia-forming austenitics trended with the level of Cr and Ni additions, with small mass losses consistent with Cr oxy-hydroxide volatilization processes for the higher 25Cr/25-35Ni HK and HP type alloys, and transition to rapid Fe-base oxide formation and scale spallation in the lower 19Cr/12Ni CF8C plus type alloy. In contrast, small positive mass changes consistent with protective alumina scale formation were observed for the cast AFA alloy under all conditions studied. Implications of these findings for diesel exhaust system components are discussed.« less

  2. The influence of zinc chloride and zinc oxide nanoparticles on air-time survival in freshwater mussels.

    PubMed

    Gagné, François; Auclair, Joëlle; Peyrot, Caroline; Wilkinson, Kevin J

    2015-01-01

    The purpose of this study was to determine the cumulative effects of exposure to either dissolved zinc or nanozinc oxide (nanoZnO) and air-time survival in freshwater mussels. Mussels were exposed to each forms of zinc for 96h then placed in air to determine survival time. A sub-group of mussels before and after 7days of exposure to air were kept aside for the determination of the following biomarkers: arachidonate-dependent cyclooxygenase (COX) and peroxidase (inflammation and oxidative stress), lipid metabolism (total lipids, esterases activity, HO-glycerol, acetyl CoA and phospholipase A2) and lipid damage (lipid peroxidation [LPO]). The results showed that air-time survival was decreased from a mean value of 18.5days to a mean value of 12days in mussels exposed to 2.5mg/L of nanoZnO although it was not lethal based on shell opening at concentrations below 50mg/L after 96h. In mussels exposed to zinc only, the median lethal concentration was estimated at 16mg/L (10-25 95% CI). The air-time survival did not significantly change in mussels exposed to the same concentration of dissolved Zn. Significant weight losses were observed at 0.5mg/L of nanoZnO and at 2.5mg/L for dissolved zinc chloride, and were also significantly correlated with air-time survival (r=0.53; p<0.01). Air exposure significantly increased COX activity in control mussels and in mussels exposed to 0.5mg/L of nanoZnO and zinc chloride. The data also suggested fatty acid breakdown and β-oxidation. Mussels exposed to contaminants are more susceptible to prolonged exposure to air during low water levels.

  3. Microwave cavity spectrometer for process monitoring of ethylene oxide sterilization

    NASA Astrophysics Data System (ADS)

    Zhu, Z.; Gibson, C.; Samuel, A. H.; Matthews, I. P.

    1993-01-01

    This article reports a novel and simple cavity spectrometer for process monitoring of ethylene oxide sterilization, in which the source frequency, cavity resonant frequency, and gas absorption center frequency are asynchronous with respect to each other, thus, enabling sophisticated signal enhancement techniques to be employed without the need to engage the Stark effect. The operation of the device is such that the source frequency sweeps across a given range (F1 to F2) which contains one of the absorption peaks of the analyte gas (gases) of interest while the cavity resonant frequency Fr is oscillated within the profile of the absorption peak. Signal enhancement is achieved by adding a relatively small magnitude/high-frequency ``dither'' signal to the source frequency sweep pattern. The salient information of the gas absorption due to the oscillation of the resonant frequency of the cavity is carried by the ``dither'' signal and amplified and extracted by a series of tuned amplifiers and demodulators. Although the device is still at the initial design stage, a working prototype has been constructed in order to test the feasibility of the novel asynchronous modulation technique. This was achieved by successfully demonstrating that the device operates in an expected manner to within a standard error of 8.3%. It is believed that this error largely results from mechanical components. The significance of this error is greatly reduced when the spectrometer is operated in a large signal scanning mode as is the case when we apply the ``power saturation'' technique to measure the concentration of ethylene oxide in the resonant cavity. This measurement showed that there is a good linear correlation between the output signal and the concentration of ethylene oxide gas (to within a standard error of 4%).

  4. Air impacts of increased natural gas acquisition, processing, and use: a critical review.

    PubMed

    Moore, Christopher W; Zielinska, Barbara; Pétron, Gabrielle; Jackson, Robert B

    2014-01-01

    During the past decade, technological advancements in the United States and Canada have led to rapid and intensive development of many unconventional natural gas plays (e.g., shale gas, tight sand gas, coal-bed methane), raising concerns about environmental impacts. Here, we summarize the current understanding of local and regional air quality impacts of natural gas extraction, production, and use. Air emissions from the natural gas life cycle include greenhouse gases, ozone precursors (volatile organic compounds and nitrogen oxides), air toxics, and particulates. National and state regulators primarily use generic emission inventories to assess the climate, air quality, and health impacts of natural gas systems. These inventories rely on limited, incomplete, and sometimes outdated emission factors and activity data, based on few measurements. We discuss case studies for specific air impacts grouped by natural gas life cycle segment, summarize the potential benefits of using natural gas over other fossil fuels, and examine national and state emission regulations pertaining to natural gas systems. Finally, we highlight specific gaps in scientific knowledge and suggest that substantial additional measurements of air emissions from the natural gas life cycle are essential to understanding the impacts and benefits of this resource. PMID:24588259

  5. Air impacts of increased natural gas acquisition, processing, and use: a critical review.

    PubMed

    Moore, Christopher W; Zielinska, Barbara; Pétron, Gabrielle; Jackson, Robert B

    2014-01-01

    During the past decade, technological advancements in the United States and Canada have led to rapid and intensive development of many unconventional natural gas plays (e.g., shale gas, tight sand gas, coal-bed methane), raising concerns about environmental impacts. Here, we summarize the current understanding of local and regional air quality impacts of natural gas extraction, production, and use. Air emissions from the natural gas life cycle include greenhouse gases, ozone precursors (volatile organic compounds and nitrogen oxides), air toxics, and particulates. National and state regulators primarily use generic emission inventories to assess the climate, air quality, and health impacts of natural gas systems. These inventories rely on limited, incomplete, and sometimes outdated emission factors and activity data, based on few measurements. We discuss case studies for specific air impacts grouped by natural gas life cycle segment, summarize the potential benefits of using natural gas over other fossil fuels, and examine national and state emission regulations pertaining to natural gas systems. Finally, we highlight specific gaps in scientific knowledge and suggest that substantial additional measurements of air emissions from the natural gas life cycle are essential to understanding the impacts and benefits of this resource.

  6. Magnesium Recycling of Partially Oxidized, Mixed Magnesium-Aluminum Scrap through Combined Refining and Solid Oxide Membrane Electrolysis Processes

    SciTech Connect

    Xiaofei Guan; Peter A. Zink; Uday B. Pal; Adam C. Powell

    2012-01-01

    Pure magnesium (Mg) is recycled from 19g of partially oxidized 50.5wt.% Mg-Aluminum (Al) alloy. During the refining process, potentiodynamic scans (PDS) were performed to determine the electrorefining potential for magnesium. The PDS show that the electrorefining potential increases over time as the magnesium content inside the Mg-Al scrap decreases. Up to 100% percent of magnesium is refined from the Mg-Al scrap by a novel refining process of dissolving magnesium and its oxide into a flux followed by vapor phase removal of dissolved magnesium and subsequently condensing the magnesium vapor. The solid oxide membrane (SOM) electrolysis process is employed in the refining system to enable additional recycling of magnesium from magnesium oxide (MgO) in the partially oxidized Mg-Al scrap. The combination of the refining and SOM processes yields 7.4g of pure magnesium.

  7. Magnesium Recycling of Partially Oxidized, Mixed Magnesium-Aluminum Scrap Through Combined Refining and Solid Oxide Membrane (SOM) Electrolysis Processes

    SciTech Connect

    Guan, Xiaofei; Zink, Peter; Pal, Uday

    2012-03-11

    Pure magnesium (Mg) is recycled from 19g of partially oxidized 50.5wt.%Mg-Aluminum (Al) alloy. During the refining process, potentiodynamic scans (PDS) were performed to determine the electrorefining potential for magnesium. The PDS show that the electrorefining potential increases over time as the Mg content inside the Mg-Al scrap decreases. Up to 100% percent of magnesium is refined from the Mg-Al scrap by a novel refining process of dissolving magnesium and its oxide into a flux followed by vapor phase removal of dissolved magnesium and subsequently condensing the magnesium vapors in a separate condenser. The solid oxide membrane (SOM) electrolysis process is employed in the refining system to enable additional recycling of magnesium from magnesium oxide (MgO) in the partially oxidized Mg-Al scrap. The combination of the refining and SOM processes yields 7.4g of pure magnesium; could not collect and weigh all of the magnesium recovered.

  8. Workshop in Support of the Secondary National Ambient Air Quality Standards for Nitrogen (NOx) and Sulfur Oxides (SOx)

    EPA Science Inventory

    EPA is announcing a workshop to discuss policy-relevant science to Inform EPA’s "Review of the Secondary National Ambient Air Quality Standards (NAAQS) for Oxides of Nitrogen and Sulfur" report. The workshop is being organized by EPA’s Office of Research and Development’s, Nation...

  9. What Is Happening when the Blue Bottle Bleaches: An Investigation of the Methylene Blue-Catalyzed Air Oxidation of Glucose

    ERIC Educational Resources Information Center

    Anderson, Laurens; Wittkopp, Stacy M.; Painter, Christopher J.; Liegel, Jessica J.; Schreiner, Rodney; Bell, Jerry A.; Shakhashiri, Bassam Z.

    2012-01-01

    An investigation of the Blue Bottle Experiment, a well-known lecture demonstration reaction involving the dye-catalyzed air oxidation of a reducing sugar in alkaline solution, has delineated the sequence of reactions leading to the bleaching of the dye, the regeneration of color, and so forth. Enolization of the sugar is proposed as a key step in…

  10. Storage of LWR spent fuel in air: Volume 1: Design and operation of a spent fuel oxidation test facility

    SciTech Connect

    Thornhill, C.K.; Campbell, T.K.; Thornhill, R.E.

    1988-12-01

    This report describes the design and operation and technical accomplishments of a spent-fuel oxidation test facility at the Pacific Northwest Laboratory. The objective of the experiments conducted in this facility was to develop a data base for determining spent-fuel dry storage temperature limits by characterizing the oxidation behavior of light-water reactor (LWR) spent fuels in air. These data are needed to support licensing of dry storage in air as an alternative to spent-fuel storage in water pools. They are to be used to develop and validate predictive models of spent-fuel behavior during dry air storage in an Independent Spent Fuel Storage Installation (ISFSI). The present licensed alternative to pool storage of spent fuel is dry storage in an inert gas environment, which is called inerted dry storage (IDS). Licensed air storage, however, would not require monitoring for maintenance of an inert-gas environment (which IDS requires) but does require the development of allowable temperature limits below which UO/sub 2/ oxidation in breached fuel rods would not become a problem. Scoping tests at PNL with nonirradiated UO/sub 2/ pellets and spent-fuel fragment specimens identified the need for a statistically designed test matrix with test temperatures bounding anticipated maximum acceptable air-storage temperatures. This facility was designed and operated to satisfy that need. 7 refs.

  11. Oxidation Behavior of Mo-Si-B Alloys in Wet Air

    SciTech Connect

    M. Kramer; A. Thom; O. Degirmen; V. Behrani; M. Akinc

    2002-04-22

    Multiphase composite alloys based on the Mo-Si-B system are candidate materials for ultra-high temperature applications. In non load-bearing uses such as thermal barrier coatings or heat exchangers in fossil fuel burners, these materials may be ideally suited. The present work investigated the effect of water vapor on the oxidation behavior of Mo-Si-B phase assemblages. Three alloys were studied: Alloy 1 = Mo{sub 5}Si{sub 3}B{sub x} (T1)- MoSi{sub 2}- MoB, Alloy 2 = T1- Mo{sub 5}SiB{sub 2} (T2)- Mo{sub 3}Si, and Alloy 3 = Mo- T2- Mo{sub 3}Si. Tests were conducted at 1000 and 1100C in controlled atmospheres of dry air and wet air nominally containing 18, 55, and 150 Torr H{sub 2}O. The initial mass loss of each alloy was approximately independent of the test temperature and moisture content of the atmosphere. The magnitude of these initial losses varied according to the Mo content of the alloys. All alloys formed a continuous, external silica scale that protected against further mass change after volatilization of the initially formed MoO{sub 3}. All alloys experienced a small steady state mass change, but the calculated rates cannot be quantitatively compared due to statistical uncertainty in the individual mass measurements. Of particular interest is that Alloy 3, which contains a significant volume fraction of Mo metal, formed a protective scale. All alloys formed varying amounts of subscale Mo and MoO{sub 2}. This implies that oxygen transport through the external silica scale has been significantly reduced. For all alloys, water vapor accelerated the growth of a multiphase interlayer at the silica scale/unoxidized alloy interface. This interlayer is likely composed of fine Mo and MoO{sub 2} that is dispersed within a thin silica matrix. Alloy 3 was particularly sensitive to water accelerated growth of this interlayer. At 1100 C, the scale thickness after 300 hours increased from about 20 mm in dry air to nearly 100 mm in wet air.

  12. Single-Step Process toward Achieving Superhydrophobic Reduced Graphene Oxide.

    PubMed

    Li, Zhong; Tang, Xiu-Zhi; Zhu, Wenyu; Thompson, Brianna C; Huang, Mingyue; Yang, Jinglei; Hu, Xiao; Khor, Khiam Aik

    2016-05-01

    We report the first use of spark plasma sintering (SPS) as a single-step process to achieve superhydrophobic reduced graphene oxide (rGO). It was found that SPS was capable of converting smooth and electrically insulating graphene oxide (GO) sheets into highly electrically conductive rGO with minimum residual oxygen and hierarchical roughness which could be well retained after prolonged ultrasonication. At a temperature of 500 °C, which is lower than the conventional critical temperature for GO exfoliation, GO was successfully exfoliated, reduced, and hierarchically roughened. rGO fabricated by only 1 min of treatment at 1050 °C was superhydrophobic with a surface roughness (Ra) 10 times as large as that of GO as well as an extraordinarily high C:O ratio of 83.03 (atom %) and water contact angle of 153°. This demonstrates that SPS is a superior GO reduction technique, which enabled superhydrophobic rGO to be quickly and effectively achieved in one single step. Moreover, the superhydrophobic rGO fabricated by SPS showed an impressive bacterial antifouling and inactivation effect against Escherichia coli in both aqueous solution and the solid state. It is envisioned that the superhydrophobic rGO obtained in this study can be potentially used for a wide range of industrial and biomedical applications, such as the fabrication of self-cleaning and antibacterial surfaces.

  13. Stabilized leachates: sequential coagulation-flocculation + chemical oxidation process.

    PubMed

    Rivas, F Javier; Beltrán, Fernando; Carvalho, Fátima; Acedo, Benito; Gimeno, Olga

    2004-12-10

    The combined sedimentation-chemical oxidation treatment of medium-stabilized landfill leachates has been investigated. The sequence of stages implemented was: (a) coagulation-flocculation by pH decrease (pH 2) to acidic conditions (COD removal approximately 25% related to COD0 approximately 7500 ppm); (b) coagulation-flocculation by Fe(III) addition (0.01 M) at pH 3.5 (COD removal approximately 40% related to COD of supernatant after step (a); (c) Fenton (Fe(III) = 0.01 M; H2O2 = 1.0 M) oxidation (COD removal approximately 80% related to COD of supernatant after step (a); and (d) coagulation-flocculation of Fenton's effluent at pH 3.5 (COD removal approximately 90% related to COD of supernatant after step (a). The use of Kynch theory allows for the design of clarifiers based on the amount of solids fed. For a general example of 1000 m3 day(-1) of a feeding stream, clarifier area values of 286,111 and 231 m2 were calculated for compacting indices of 3.7, 2.67 and 2.83 corresponding to the first, second and third consecutive sedimentation processes, respectively, (steps (a), (b) and (d)).

  14. Single-Step Process toward Achieving Superhydrophobic Reduced Graphene Oxide.

    PubMed

    Li, Zhong; Tang, Xiu-Zhi; Zhu, Wenyu; Thompson, Brianna C; Huang, Mingyue; Yang, Jinglei; Hu, Xiao; Khor, Khiam Aik

    2016-05-01

    We report the first use of spark plasma sintering (SPS) as a single-step process to achieve superhydrophobic reduced graphene oxide (rGO). It was found that SPS was capable of converting smooth and electrically insulating graphene oxide (GO) sheets into highly electrically conductive rGO with minimum residual oxygen and hierarchical roughness which could be well retained after prolonged ultrasonication. At a temperature of 500 °C, which is lower than the conventional critical temperature for GO exfoliation, GO was successfully exfoliated, reduced, and hierarchically roughened. rGO fabricated by only 1 min of treatment at 1050 °C was superhydrophobic with a surface roughness (Ra) 10 times as large as that of GO as well as an extraordinarily high C:O ratio of 83.03 (atom %) and water contact angle of 153°. This demonstrates that SPS is a superior GO reduction technique, which enabled superhydrophobic rGO to be quickly and effectively achieved in one single step. Moreover, the superhydrophobic rGO fabricated by SPS showed an impressive bacterial antifouling and inactivation effect against Escherichia coli in both aqueous solution and the solid state. It is envisioned that the superhydrophobic rGO obtained in this study can be potentially used for a wide range of industrial and biomedical applications, such as the fabrication of self-cleaning and antibacterial surfaces. PMID:27064825

  15. Anaerobic oxidation of methane: an "active" microbial process.

    PubMed

    Cui, Mengmeng; Ma, Anzhou; Qi, Hongyan; Zhuang, Xuliang; Zhuang, Guoqiang

    2015-02-01

    The anaerobic oxidation of methane (AOM) is an important sink of methane that plays a significant role in global warming. AOM was first found to be coupled with sulfate reduction and mediated by anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB). ANME, often forming consortia with SRB, are phylogenetically related to methanogenic archaea. ANME-1 is even able to produce methane. Subsequently, it has been found that AOM can also be coupled with denitrification. The known microbes responsible for this process are Candidatus Methylomirabilis oxyfera (M. oxyfera) and Candidatus Methanoperedens nitroreducens (M. nitroreducens). Candidatus Methylomirabilis oxyfera belongs to the NC10 bacteria, can catalyze nitrite reduction through an "intra-aerobic" pathway, and may catalyze AOM through an aerobic methane oxidation pathway. However, M. nitroreducens, which is affiliated with ANME-2d archaea, may be able to catalyze AOM through the reverse methanogenesis pathway. Moreover, manganese (Mn(4+) ) and iron (Fe(3+) ) can also be used as electron acceptors of AOM. This review summarizes the mechanisms and associated microbes of AOM. It also discusses recent progress in some unclear key issues about AOM, including ANME-1 in hypersaline environments, the effect of oxygen on M. oxyfera, and the relationship of M. nitroreducens with ANME. PMID:25530008

  16. Anaerobic oxidation of methane: an “active” microbial process

    PubMed Central

    Cui, Mengmeng; Ma, Anzhou; Qi, Hongyan; Zhuang, Xuliang; Zhuang, Guoqiang

    2015-01-01

    The anaerobic oxidation of methane (AOM) is an important sink of methane that plays a significant role in global warming. AOM was first found to be coupled with sulfate reduction and mediated by anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB). ANME, often forming consortia with SRB, are phylogenetically related to methanogenic archaea. ANME-1 is even able to produce methane. Subsequently, it has been found that AOM can also be coupled with denitrification. The known microbes responsible for this process are Candidatus Methylomirabilis oxyfera (M. oxyfera) and Candidatus Methanoperedens nitroreducens (M. nitroreducens). Candidatus Methylomirabilis oxyfera belongs to the NC10 bacteria, can catalyze nitrite reduction through an “intra-aerobic” pathway, and may catalyze AOM through an aerobic methane oxidation pathway. However, M. nitroreducens, which is affiliated with ANME-2d archaea, may be able to catalyze AOM through the reverse methanogenesis pathway. Moreover, manganese (Mn4+) and iron (Fe3+) can also be used as electron acceptors of AOM. This review summarizes the mechanisms and associated microbes of AOM. It also discusses recent progress in some unclear key issues about AOM, including ANME-1 in hypersaline environments, the effect of oxygen on M. oxyfera, and the relationship of M. nitroreducens with ANME. PMID:25530008

  17. Change in endotracheal tube cuff pressure during nitrous oxide anaesthesia: a comparison between air and distilled water cuff inflation.

    PubMed

    Ahmad, N L; Norsidah, A M

    2001-10-01

    In this prospective, randomized controlled trial, changes in endotracheal tube cuff pressure were studied in 60 patients undergoing elective surgery under general anaesthesia with nitrous oxide and oxygen. The cuffs were inflated with either air or distilled water. The mean pressure in the air-filled cuffs increased steadily throughout the procedure, reaching 47.5 +/- 7.3 cmH2O at one hour compared with 31.6 +/- 2.4 cmH2O mean pressure in the water-filled cuffs. The pressure and the rate of rise in cuff pressure were significantly lower (P<0.05) in the water-filled cuffs throughout the hour of study. When an endotracheal tube cuff is distended with water, the rise in cuff pressure during nitrous oxide anaesthesia is lower than that of an air-filled cuff.

  18. Process for removal of hazardous air pollutants from coal

    DOEpatents

    Akers, David J.; Ekechukwu, Kenneth N.; Aluko, Mobolaji E.; Lebowitz, Howard E.

    2000-01-01

    An improved process for removing mercury and other trace elements from coal containing pyrite by forming a slurry of finely divided coal in a liquid solvent capable of forming ions or radicals having a tendency to react with constituents of pyrite or to attack the bond between pyrite and coal and/or to react with mercury to form mercury vapors, and heating the slurry in a closed container to a temperature of at least about 50.degree. C. to produce vapors of the solvent and withdrawing vapors including solvent and mercury-containing vapors from the closed container, then separating mercury from the vapors withdrawn.

  19. Process-Scale Modeling of Atmosphere-Snowpack Exchange of Nitrogen Oxides

    NASA Astrophysics Data System (ADS)

    Murray, K. A.; Doskey, P. V.; Ganzeveld, L.

    2013-12-01

    Snowpack over glacial ice is a reservoir for reactive nitrogen gases. Previous studies indicate nitrogen oxides (NOx) are generated in snowpack interstitial air through photolysis of nitrate (NO3-). Gradients in NOx mixing ratios between snowpack interstitial air and the overlying atmosphere regulate exchange of NOx with snowpack, which affects the Arctic ozone budget and climate. To better understand the dynamics of cryosphere-atmosphere exchange of NOx in the Arctic, we collected 2 years of meteorological and chemical data in and above the snowpack at Summit, Greenland. The comprehensive dataset indicates NOx emissions are episodic, with NOx enhancements in snowpack in early spring during high wind speed events (10-20 mph), which elevate NOx levels to ~500 pptv at depths of 2.5 m. Analysis of the observations will be based upon application of a 1-D process-scale model of atmosphere-snowpack exchange of NOx. The model will include representations of the snowpack chemistry in gas and aqueous phases, mass transfer of chemical species between phases, and physical transport by diffusion and wind pumping. The model will calculate the chemical and physical tendencies in three dimensions: depth, time, and intensity. Analysis of the tendencies will allow us to perform model sensitivity tests of pertinent snowpack physical and chemical processes. The end-goal of the project is to simplify the major tendencies into a parameterized model add-on for use in global models to determine the importance of properly representing snowpack in global model simulations.

  20. Oxidation enhancement of submicron organic aerosols by fog processing

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Ge, X.; Collier, S.; Setyan, A.; Xu, J.; Sun, Y.

    2011-12-01

    During 2010 wintertime, a measurement study was carried out at Fresno, California, using an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) combined with a Scanning Mobility Particle Sizer (SMPS). Four fog events occurred during the first week of the campaign. While ambient aerosol was sampled into the HR-ToF-AMS, fog water samples were collected, and were later aerosolized and analyzed via HR-TOF-AMS in the laboratory. We performed Positive Matrix Factorization (PMF) on the AMS ambient organic mass spectra, and identified four OA factors: hydrocarbon-like OA (HOA) likely from vehicle emissions, cooking influenced OA (COA), biomass burning OA (BBOA) representing residential wood combustion, and an oxygenated OA (OOA) that has an average O/C ratio of 0.42. The time series of the OOA factor correlates best with that of sulfate (R2 =0.54 ) during fog events, suggesting that aqueous phase processing may have strongly affected OOA production during wintertime in Fresno. We further investigate the OOA compositions and elemental ratios before, during, and after the fog events, as well as those of dissolved organic matter (DOM) in fog waters to study the influence of aqueous phase processing on OA compositions. Results of fog sample analysis shows an enhancement of oxidation of DOM in 11 separate fog samples. Further factor analysis of the fog DOM data will elucidate the possible mechanisms by which fog processing enhances oxidation of aerosol. In addition, in order to investigate the influence of aqueous processing on OA, we used the Extended Aerosol Inorganic Model (E-AIM) (http://www.aim.env.uea.ac.uk/aim/aim.php) to estimate aerosol phase water contents based on the AMS measured aerosol composition. The predicted water content has a good correlation with sulfate and OOA . We will further explore the correlations between particle phase water with organic aerosol characteristics to discuss the influence of aqueous phase processing on

  1. Chemiresistive gas sensors employing solution-processed metal oxide quantum dot films

    SciTech Connect

    Liu, Huan Xu, Songman; Li, Min; Shao, Gang; Zhang, Wenkai; Wei, Wendian; He, Mingze; Song, Huaibing; Gao, Liang; Song, Haisheng; Tang, Jiang

    2014-10-20

    We report low-temperature chemiresistive gas sensors based on tin oxide colloidal quantum dots (CQDs), in which the benefits of CQDs such as extremely small crystal size, solution-processability, and tunable surface activity are exploited to enhance the gas-sensing effect. The sensor fabrication is simply employing spin-coating followed by a solid-state ligand exchange treatment at room temperature in air ambient. The optimal gas sensor exhibited rapid and significant decrease in resistance upon H{sub 2}S gas exposure when operated at 70 °C, and it was fully recoverable upon gas release. We observed a power law correlation between the sensor response and H{sub 2}S gas concentration, and the sensing mechanism was discussed using the completely depletion model with a flat band diagram.

  2. Pro-oxidant and antioxidant processes in aquatic invertebrates.

    PubMed

    Canesi, Laura

    2015-03-01

    Most aquatic organisms behave as conformers with respect to environmental variables, including changes in O2 availability. Aquatic species that show tolerance to hypoxia/anoxia or hyperoxia can be excellent models for investigating physiological and biochemical adaptations that deal with changing O2 and consequent changes in metabolic rate and production of reactive oxygen species (ROS). Here, I summarize selected data on ROS production and antioxidant defenses in a model marine invertebrate, the bivalve Mytilus, under different environmental and physiological conditions. An example of other bivalves adapted to particular environments (the Antarctic Sea) is also reported. These studies contributed to the knowledge on pro-oxidant and antioxidant processes in aquatic invertebrates from comparative and environmental perspectives. A common role for metallothioneins in antioxidant protection in mammals and aquatic invertebrates is underlined in different conditions, from human disease to responses to environmental exposure to heavy metals.

  3. Secondary hospital wastewater detoxification and disinfection by advanced oxidation processes.

    PubMed

    Machado, E L; Kist, L T; Schmidt, R; Hoeltz, J M; Dalberto, D; Alcayaga, E L A

    2007-10-01

    Secondary hospital wastewater treatment was investigated as an alternative to detoxification and disinfection after anaerobic digestion in a hospital located in southern Brazil. Tertiary and secondary effluents were assessed by general parameters. The use of advanced oxidation processes (UV/O3 and UV/TiO2/O3) showed potential capacity for disinfection and detoxification of wastewater effluents. The UV/TiO2/O3 method yielded the best results, decreasing toxicity of EC50 = 65 to nontoxic levels, also reducing MPN/100ml of 1.1 x 10(6) to values less than 2 and increasing wastewater biodegradability. The low energetic consumption of the proposed UV/TiO2/O3 method can be considered operationally advantageous.

  4. Cobalt-based nanocatalysts for green oxidation and hydrogenation processes.

    PubMed

    Jagadeesh, Rajenahally V; Stemmler, Tobias; Surkus, Annette-Enrica; Bauer, Matthias; Pohl, Marga-Martina; Radnik, Jörg; Junge, Kathrin; Junge, Henrik; Brückner, Angelika; Beller, Matthias

    2015-06-01

    This protocol describes the preparation of cobalt-based nanocatalysts and their applications in environmentally benign redox processes for fine chemical synthesis. The catalytically active material consists of nanoscale Co3O4 particles surrounded by nitrogen-doped graphene layers (NGrs), which have been prepared by pyrolysis of phenanthroline-ligated cobalt acetate on carbon. The resulting materials have been found to be excellent catalysts for the activation of both molecular oxygen and hydrogen; in all tested reactions, water was the only by-product. By applying these catalysts, green oxidations of alcohols and hydrogenation of nitroarenes for the synthesis of nitriles, esters and amines are demonstrated. The overall time required for catalyst preparation and for redox reactions is 35 h and 10-30 h, respectively.

  5. Treatment of biomass-gasification wastewaters by wet-air oxidation

    SciTech Connect

    English, C.J.

    1981-09-01

    Production of synthetic natural gas from gasification of biomass results in the generation of a high-strength wastewater that is difficult to treat by conventional means. This study investigated the use of wet air oxidation (WAO) as a treatment method for these wastewaters. A literature review was conducted to identify the suitability of WAO for the treatment of high-strength industrial wastewaters and to determine typical operating conditions for such treatment. Data presented in the literature showed that WAO should be suitable for treatment. Data presented in the literature showed that WAO should be suitable for treatment of biomass gasification wastewaters (BGW), and a laboratory treatability study was designed. BGW, having an initial chemical oxygen demand (COD) of 30,800 mg/1 and initial color of 183,000 APHA units, was treated in a laboratory autoclave for 20, 40, 60, 120, and 180 min at temperatures and pressures of 150/sup 0/C, 5.1 MPa (750 psi); 200/sup 0/C, 6.9 MPa (1000 psi); 250/sup 0/C, 10.3 MPa (1500 psi); and 300/sup 0/C, 13.8 MPa (2000 psi). Maximum COD removals of 0% for the 150/sup 0/C, 5.2 MPa (750 psi) runs; 40% for the 200/sup 0/C, 6.9 MPa (1000 psi) runs, 55% for the 250/sup 0/C, 10.3 MPa (1500 psi) runs; and 85% for the 300/sup 0/C, 13.8 MPa (2000 psi) runs were measured. Maximum color removals for these respective runs were 56%, 82%, 97%, and 99%. Initial removal rates of COD and color were observed to increase with reaction temperature. The experimental results suggest that oxidation of BGW organics by WAO occurs in a stepwise fashion with large organic molecules first being hydrolyzed and then partially oxidized to low molecular weight intermediates. Complete oxidation of these intermediates is more difficult and most easily accomplished at high reaction temperatures. The best application of WAO to treatment of BGW appears to be as a pretreatment to biological treatment and it is recommended that this application be investigated.

  6. The Active Molybdenum Oxide Phase in the Methanol Oxidation to Formaldehyde (Formox Process): A DFT Study.

    PubMed

    Rellán-Piñeiro, Marcos; López, Núria

    2015-07-01

    Methanol is oxidised to formaldehyde by the Formox process, in which molybdenum oxides, usually doped with iron, are the catalyst. The active phase of the catalysts and the reasons for the selectivity observed are still unknown. We present a density functional theory based study that indicates the unique character of Mo(VI)¢Mo(IV) pairs as the most active and selective sites and indicates the active sites on the surface, the controlling factors of selectivity, and the role of the dopant. Iron reduces the energy requirements of the redox Mo(VI)¢Mo(IV) pair by acting as an electron reservoir that sets in if required. Our present study paves the way towards a better understanding of the process.

  7. Process to produce silicon carbide fibers using a controlled concentration of boron oxide vapor

    NASA Technical Reports Server (NTRS)

    Barnard, Thomas Duncan (Inventor); Lipowitz, Jonathan (Inventor); Nguyen, Kimmai Thi (Inventor)

    2000-01-01

    A process for producing polycrystalline silicon carbide includes heating an amorphous ceramic fiber that contains silicon and carbon in an environment containing boron oxide vapor. The boron oxide vapor is produced in situ by the reaction of a boron containing material such as boron carbide and an oxidizing agent such as carbon dioxide, and the amount of boron oxide vapor can be controlled by varying the amount and rate of addition of the oxidizing agent.

  8. Process to produce silicon carbide fibers using a controlled concentration of boron oxide vapor

    NASA Technical Reports Server (NTRS)

    Barnard, Thomas Duncan (Inventor); Lipowitz, Jonathan (Inventor); Nguyen, Kimmai Thi (Inventor)

    2001-01-01

    A process for producing polycrystalline silicon carbide by heating an amorphous ceramic fiber that contains silicon and carbon in an environment containing boron oxide vapor. The boron oxide vapor is produced in situ by the reaction of a boron containing material such as boron carbide and an oxidizing agent such as carbon dioxide, and the amount of boron oxide vapor can be controlled by varying the amount and rate of addition of the oxidizing agent.

  9. Short-term respiratory effects of polluted ambient air: a laboratory study of volunteers in a high-oxidant community.

    PubMed

    Linn, W S; Jones, M P; Bachmayer, E A; Spier, C E; Mazur, S F; Avol, E L; Hackney, J D

    1980-02-01

    To investigate short-term health effects of community air pollution directly, we developed a mobile laboratory allowing "blind" exposures of volunteers to polluted ambient air and to purified air at similar temperature and humidity. Subjects (30 asthmatic, 34 normal) from the surrounding area were studied at Duarte, California, a Los Angeles suburb subject to frequent photochemical oxidant pollution. Each was exposed to a close approximation of outdoor ambient air for 2 h with intermittent light exercise. Lung function and symptoms were evaluated pre- and post-exposure. A control (purified air) study took place several weeks later. Mean ambient air exposure concentrations were near 0.22 ppm for ozone and 200 micrograms/m3 for total suspended particulate. Ambient air exposures were associated with small significant losses in forced expiratory performance and total lung capacity. The responses of asthmatic and normal subjects were generally not significantly different, possibly because many normal subjects had a history of allergy and appeared atypically reactive to respiratory insults. In the normal subjects, a small significant increase in reported symptoms was seen with ambient air exposures compared with the control. In the asthmatics, the increase was not significant. Over-all, only slight effects attributable to exposure were found, even though a severely polluted area and a presumed high-risk population were chosen for study. PMID:7362133

  10. Distributed processing and fiber optic communications in air data measurement

    NASA Technical Reports Server (NTRS)

    Farry, K. A.; Stengel, R. F.

    1982-01-01

    This paper describes the application of distributed processing, fiber optics, and hardware redundancy to collecting airstream data in Princeton's digitally controlled Variable-Response Research Aircraft (VRA). Microprocessor-controlled instrumentation packages in each wingtip of the aircraft collect angle-of-attack and sideslip data in digital form; after scaling, filtering, and calibrating the data, they send it to the aircraft's microprocessor Digital Flight Control System (micro-DFCS) via digital fiber optic data links. Each wingtip's package is independent of the other; therefore, the system has dual hardware redundancy. The fiber optic link design is presented as well as a description of the calibration and communications software. Translation of the system's dual redundancy into fault tolerance is also covered. Results of preliminary flight tests are included.

  11. Air stripping and emissions control technologies: Field testing of countercurrent packings, rotary air stripping, catalytic oxidation, and adsorption materials. Final report, April 1987-June 1989

    SciTech Connect

    Wilson, J.H.; Counce, R.M.; Lucero, A.J.; Jennings, H.L.; Singh, S.P.

    1992-05-01

    The objective of this activity was to field test innovative air stripping with emissions control technologies. The scale of the various components used in these tests was selected such that results would be useful for better predicting the performance of application-scale equipment. The goal of this effort was to provide managers and engineers with necessary information so that decisions relating to the application of this technology can proceed on a rational basis. Conventional countercurrent air stripping (with 4 different packing materials) were compared to a centrifugal contactor, also known as a rotary air stripper. Emissions control tests showed that the activity of the noble metal catalyst was lost before any useful abatement results were obtained. This loss in activity was attributed to poisoning by sulfur stripped from the groundwater. Control of the emissions by activated carbon was achieved. Significant quantities of lighter hydrocarbons were noted in the stripper effluent that were not effectively adsorbed by the carbon. No generally useful results ere obtained for control of emissions by molecular sieves.... Air stripping, Rotary air stripper, VOCs, Fuel contamination, Catalytic oxidations, Carbon adsorption, Molecular sieves.

  12. DEVELOPMENT OF SULFATE RADICAL-BASED CHEMICAL OXIDATION PROCESSES FOR GROUNDWATER REMEDIATION

    EPA Science Inventory

    This study investigates the development of novel sulfate radical-based chemical oxidation processes for treatment of groundwater contaminants. Environmentally friendly transition metal (Fe (II), Fe (III)) has been evaluated for the activation of common oxidants (peroxymonosulfat...

  13. The role of sea spray in cleansing air pollution over ocean via cloud processes.

    PubMed

    Rosenfeld, Daniel; Lahav, Ronen; Khain, Alexander; Pinsky, Mark

    2002-09-01

    Particulate air pollution has been shown to strongly suppress precipitation from convective clouds over land. New observations show that precipitation from similar polluted clouds over oceans is much less affected, because large sea salt nuclei override the precipitation suppression effect of the large number of small pollution nuclei. Raindrops initiated by the sea salt grow by collecting small cloud droplets that form on the pollution particles, thereby cleansing the air. Therefore, sea salt helps cleanse the atmosphere of the air pollution via cloud processes. This implies that over oceans, the climatic aerosol indirect effects are significantly smaller than current estimates.

  14. Land Surface Process and Air Quality Research and Applications at MSFC

    NASA Technical Reports Server (NTRS)

    Quattrochi, Dale; Khan, Maudood

    2007-01-01

    This viewgraph presentation provides an overview of land surface process and air quality research at MSFC including atmospheric modeling and ongoing research whose objective is to undertake a comprehensive spatiotemporal analysis of the effects of accurate land surface characterization on atmospheric modeling results, and public health applications. Land use maps as well as 10 meter air temperature, surface wind, PBL mean difference heights, NOx, ozone, and O3+NO2 plots as well as spatial growth model outputs are included. Emissions and general air quality modeling are also discussed.

  15. Novel process to evaporate liquid fuels and its application to the catalytic partial oxidation of diesel

    NASA Astrophysics Data System (ADS)

    Aicher, T.; Griesser, L.

    A novel process for evaporation of liquid hydrocarbons, like gasoline, diesel or kerosene, has been developed and tested. It allows to directly transfer a liquid hydrocarbon mixture into the gaseous phase avoiding all problems related to residue and carbon formation due to contact of the fuel with hot heat exchanger surfaces. This process is especially advantageous when designing combustion or reforming systems for diesel, since this fuel can not be evaporated directly. By transferring diesel into the gaseous phase, thorough mixing of the hydrocarbons with steam and air is possible, reducing the risk of carbon formation in subsequent combustion or reforming processes. In Part I, this paper describes the evaporation process and presents first experimental results. A map will be given characterizing operating conditions where the evaporation is complete. Furthermore, the composition of the evaporator products were measured providing insight into the processes taking place in the evaporator. In Part II, the paper explains how the evaporator was connected to a catalytic partial oxidation reformer reactor and presents first experimental results with diesel which showed that at temperatures around 800 °C the thermodynamic equilibrium is reached and no carbon is formed in the evaporator nor in the CPOX reactor.

  16. Test of TDA's Direct Oxidation Process for Sulfur Recovery

    SciTech Connect

    Girish Srinivas; Steven C. Gebhard; Eugene Peeples; Sandra Huzyk; Randy Welch

    2005-01-01

    This project was a Phase III pilot plant test of TDA's gas sweetening process done under realistic conditions. TDA Research Inc successfully completed the test at Whiting Petroleum's Sable San Andreas Gas Plant. The feed was approximately 228,000 standard cubic feet per day (SCFD) of gas that contained approximately 60 vol% CO{sub 2}, 20 vol% CH{sub 4} and 10 vol% C{sub 3}+ and higher hydrocarbons. The feed was associated gas from CO{sub 2} flooding operations carried out on Whiting's oil wells. The gas is collected and piped to the Sable gas plant where it is normally flared. We sited our pilot plant in line with the flare so that we could remove the hydrogen sulfide (H{sub 2}S) prior to flaring. The average H{sub 2}S concentration in the gas during the field test was 7341 ppm. The selectivity of our process for converting H{sub 2}S into elemental sulfur was essentially 100% and the catalyst converted 90% of the H{sub 2}S into sulfur and water (the remaining 10% of the H{sub 2}S passed through unconverted). Importantly, no catalyst deactivation was observed for over the course of the 1000+ hour test. Minimal (ca. 10-15 ppm) of SO{sub 2} was formed during the test. Approximately 3.6 tons of elemental sulfur was recovered from a total inlet of 3.9 tons of sulfur (as H{sub 2}S). The total amount of SO{sub 2} released from the plant (taking into account flaring of the unconverted 10% H2S) was 0.86 tons. This amount of SO{sub 2} is much lower than the normal 8 tons that would have been emitted if all of the H{sub 2}S were flared over the time of the pilot plant test. The pilot plant was simple to operate and required much less operator intervention than is typical for a new unit being commissioned. Our operator (Mr. Eugene Peeples) has more than 30 years of experience operating commercial scale liquid redox sulfur recovery processes and in his opinion, TDA's Direct Oxidation pilot plant is easier to operate than liquid systems. The ease of use and low capital and

  17. Generic process for preparing a crystalline oxide upon a group IV semiconductor substrate

    DOEpatents

    McKee, Rodney A.; Walker, Frederick J.; Chisholm, Matthew F.

    2000-01-01

    A process for growing a crystalline oxide epitaxially upon the surface of a Group IV semiconductor, as well as a structure constructed by the process, is described. The semiconductor can be germanium or silicon, and the crystalline oxide can generally be represented by the formula (AO).sub.n (A'BO.sub.3).sub.m in which "n" and "m" are non-negative integer repeats of planes of the alkaline earth oxides or the alkaline earth-containing perovskite oxides. With atomic level control of interfacial thermodynamics in a multicomponent semiconductor/oxide system, a highly perfect interface between a semiconductor and a crystalline oxide can be obtained.

  18. Solution-Processed Ultraelastic and Strong Air-Bubbled Graphene Foams.

    PubMed

    Lv, Lingxiao; Zhang, Panpan; Cheng, Huhu; Zhao, Yang; Zhang, Zhipan; Shi, Gaoquan; Qu, Liangti

    2016-06-01

    Solution-processed ultraelastic graphene foams are prepared via a convenient air-bubble-promoted synthesis. These foams can dissipate external compression through the ordered interconnecting graphene network between the bubbles without causing a local fracture and thus reliably show compressive stress of 5.4 MPa at a very high strain of 99%, setting a new benchmark for solution-processed graphene foams.

  19. MEASUREMENT OF INDOOR AIR EMISSIONS FROM DRY-PROCESS PHOTOCOPY MACHINES

    EPA Science Inventory

    The article provides background information on indoor air emissions from office equipment, with emphasis on dry-process photocopy machines. The test method is described in detail along with results of a study to evaluate the test method using four dry-process photocopy machines. ...

  20. Sm-Ba-Cu-O bulk superconductors melt-processed in air

    NASA Astrophysics Data System (ADS)

    Fujimoto, Hiroyuki; Cai, Chuanbing; Ohtabara, Emi

    2002-08-01

    Recent development shows that melt-processed YBaCuO (Y123) and light rare-earth (LRE) BaCuO superconductors have a high Jc at 77 K and high magnetic field. Solidification processes for producing RE123 superconductors are effective for obtaining high Jc and are very promising for high field application as a superconducting permanent magnet with the liquid nitrogen refrigeration. LRE BaCuO bulk superconductors melt-processed in a reduced oxygen atmosphere, named oxygen-controlled-melt-growth process, have a high Tc and Jc. However, processing in air is preferable for practical applications. In this study, we discuss Sm123 bulks melt-processed in air, and their characteristic superconducting properties. Isothermal undercooling growth in air with oxygen annealing and Nd123/MgO thin film cold seeding technique were applied in Sm 1.8Ba 2.4Cu 3.4O y/Ag system to seek the high efficiency of process, homogeneity of composition, and feasibility of batch production. Single-domain growth was achieved using this technique. The result implies that melt-processed in air applying isothermal method and thin film seeding in Sm system is fit for producing larger bulks in large scale applications.

  1. Diagnostic significance of nitric oxide concentrations in exhaled air from the airways in allergic rhinitis patients

    PubMed Central

    Krzych-Fałta, Edyta; Samoliński, Bolesław K; Zalewska, Marta

    2016-01-01

    Introduction The effect of nitric oxide (NO) on the human body is very important due its physiological regulation of the following functions of airways: modulation of ciliary movement and maintenance of sterility in sinuses. Aim To evaluate the diagnostic significance of NO concentrations in exhaled air from the upper and lower airways in patients diagnosed with allergic rhinitis (AR). Material and methods The subjects included in the study were a group of 30 people diagnosed with sensitivity to environmental allergens and a control group consisting of 30 healthy subjects. The measurement of NO in the air exhaled from the lower and upper airways was performed using an on-line method by means of Restricted Exhaled Breath (REB), as well as using the measurement procedure (chemiluminescence) set out in the guidelines prepared in 2005 by the American Thoracic Society and the European Respiratory Society. Results In the late phase of the allergic reaction, higher values of the level of exhaled NO concentration from the lower airways were observed in the groups of subjects up to the threshold values of 25.17 ppb in the group of subjects with year-round allergic rhinitis and 21.78 ppb in the group with diagnosed seasonal allergic rhinitis. The difference in the concentration of NO exhaled from the lungs between the test group and the control group in the 4th h of the test was statistically significant (p = 0.045). Conclusions Exhaled NO should be considered as a marker of airway inflammation. It plays an important role in the differential diagnosis of allergy. PMID:27279816

  2. Temperature-modulated graphene oxide resistive humidity sensor for indoor air quality monitoring

    NASA Astrophysics Data System (ADS)

    de Luca, A.; Santra, S.; Ghosh, R.; Ali, S. Z.; Gardner, J. W.; Guha, P. K.; Udrea, F.

    2016-02-01

    In this paper we present a temperature-modulated graphene oxide (GO) resistive humidity sensor that employs complementary-metal-oxide-semiconductor (CMOS) micro-electro-mechanical-system (MEMS) micro-hotplate technology for the monitoring and control of indoor air quality (IAQ). GO powder is obtained by chemical exfoliation, dispersed in water and deposited via ink-jet printing onto a low power micro-hotplate. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) show the typical layered and wrinkled morphology of the GO. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Fourier transform infra-red (FTIR) spectroscopy indicate that the GO flakes possess a significant number of oxygen containing functional groups (epoxy, carbonyl, hydroxyl) extremely attractive for humidity detection. Electro-thermal characterisation of the micro-hotplates shows a thermal efficiency of 0.11 mW per °C, resulting in a sensor DC power consumption of only 2.75 mW at 50 °C. When operated in an isothermal mode, the sensor response is detrimentally affected by significant drift, hysteretic behaviour, slow response/recovery times and hence poor RH level discrimination. Conversely, a temperature modulation technique coupled with a differential readout methodology results in a significant reduction of the sensor drift, improved linear response with a sensitivity of 0.14 mV per %, resolution below 5%, and a maximum hysteresis of +/-5% response and recovery times equal to 189 +/- 49 s and 89 +/- 5 s, respectively. These performance parameters satisfy current IAQ monitoring requirements. We have thus demonstrated the effectiveness of integrating GO on a micro-hotplate CMOS-compatible platform enabling temperature modulation schemes to be easily applied in order to achieve compact, low power, low cost humidity IAQ monitoring.In this paper we present a temperature-modulated graphene oxide (GO) resistive humidity sensor that employs complementary-metal-oxide

  3. Nitric Oxide and Oxygen Air-Contamination Effects on Extinction Limits of Non-Premixed Hydrocarbon-Air Flames for a HIFiRE Scramjet

    NASA Technical Reports Server (NTRS)

    Pellett, Gerald L.; Dawson, Lucy C.; Vaden, Sarah N.; Wilson, Lloyd G.

    2009-01-01

    Unique nitric oxide (NO) and oxygen air-contamination effects on the extinction Flame Strength (FS) of non-premixed hydrocarbon (HC) vs. air flames are characterized for 7 gaseous HCs, using a new idealized 9.3 mm straight-tube Opposed Jet Burner (OJB) at 1 atm. FS represents a laminar strain-induced extinction limit based on cross-section-average air jet velocity, Uair, that sustains combustion of a counter jet of gaseous fuel just before extinction. Besides ethane, propane, butane, and propylene, the HCs include ethylene, methane, and a 64 mole-% ethylene / 36 % methane mixture, the writer s previously recommended gaseous surrogate fuel for HIFiRE scramjet tests. The HC vs. clean air part of the work is an extension of a May 2008 JANNAF paper that characterized surrogates for the HIFiRE project that should mimic the flameholding of reformed (thermally- or catalytically-cracked) endothermic JP-like fuels. The new FS data for 7 HCs vs. clean air are thus consolidated with the previously validated data, normalized to absolute (local) axial-input strain rates, and co-plotted on a dual kinetically dominated reactivity scale. Excellent agreement with the prior data is obtained for all 7 fuels. Detailed comparisons are also made with recently published (Univ. Va) numerical results for ethylene extinction. A 2009-revised ethylene kinetic model (Univ. Southern Cal) led to predicted limits within approx. 5 % (compared to 45 %, earlier) of this writer s 2008 (and present) ethylene FSs, and also with recent independent data (Univ. Va) obtained on a new OJB system. These +/- 5 % agreements, and a hoped-for "near-identically-performing" reduced kinetics model, would greatly enhance the capability for accurate numerical simulations of surrogate HC flameholding in scramjets. The measured air-contamination effects on normalized FS extinction limits are projected to assess ongoing Arc-Heater-induced "facility test effects" of NO production (e.g., 3 mole-%) and resultant oxygen

  4. Two kinds of composite films: Graphene oxide/carbon nanotube film and graphene oxide/activated carbon film via a self-assemble preparation process

    NASA Astrophysics Data System (ADS)

    Zou, Li-feng; Ma, Nan; Sun, Mei; Ji, Tian-hao

    2014-11-01

    Two kinds of free-standing composite films, including graphene oxide and activated carbon film as well as graphene oxide and carbon nanotube film, were fabricated through a simple suspension mixing and then natural deposition process. The films were characterized by various measurement techniques in detail. The results show that the composite films without any treatment almost still remain the original properties of the corresponding precursors, and exhibit loose structure, which can be easily broken in water; whereas after treated at 200 °C in air, the films become relatively more dense, and even if immersed into concentrated strong alkali or acid for five days, they still keep the film-morphologies, but regretfully, they show obvious brittleness and slight hydrophilicity. As soon as the treated films are performed in high concentrated strong alkali for about one day, their brittleness and wettability can be improved and became good flexibility and complete hydrophilicity.

  5. Temperature-modulated graphene oxide resistive humidity sensor for indoor air quality monitoring.

    PubMed

    De Luca, A; Santra, S; Ghosh, R; Ali, S Z; Gardner, J W; Guha, P K; Udrea, F

    2016-02-28

    In this paper we present a temperature-modulated graphene oxide (GO) resistive humidity sensor that employs complementary-metal-oxide-semiconductor (CMOS) micro-electro-mechanical-system (MEMS) micro-hotplate technology for the monitoring and control of indoor air quality (IAQ). GO powder is obtained by chemical exfoliation, dispersed in water and deposited via ink-jet printing onto a low power micro-hotplate. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) show the typical layered and wrinkled morphology of the GO. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Fourier transform infra-red (FTIR) spectroscopy indicate that the GO flakes possess a significant number of oxygen containing functional groups (epoxy, carbonyl, hydroxyl) extremely attractive for humidity detection. Electro-thermal characterisation of the micro-hotplates shows a thermal efficiency of 0.11 mW per °C, resulting in a sensor DC power consumption of only 2.75 mW at 50 °C. When operated in an isothermal mode, the sensor response is detrimentally affected by significant drift, hysteretic behaviour, slow response/recovery times and hence poor RH level discrimination. Conversely, a temperature modulation technique coupled with a differential readout methodology results in a significant reduction of the sensor drift, improved linear response with a sensitivity of 0.14 mV per %, resolution below 5%, and a maximum hysteresis of ±5%; response and recovery times equal to 189 ± 49 s and 89 ± 5 s, respectively. These performance parameters satisfy current IAQ monitoring requirements. We have thus demonstrated the effectiveness of integrating GO on a micro-hotplate CMOS-compatible platform enabling temperature modulation schemes to be easily applied in order to achieve compact, low power, low cost humidity IAQ monitoring. PMID:26842731

  6. Temperature-modulated graphene oxide resistive humidity sensor for indoor air quality monitoring.

    PubMed

    De Luca, A; Santra, S; Ghosh, R; Ali, S Z; Gardner, J W; Guha, P K; Udrea, F

    2016-02-28

    In this paper we present a temperature-modulated graphene oxide (GO) resistive humidity sensor that employs complementary-metal-oxide-semiconductor (CMOS) micro-electro-mechanical-system (MEMS) micro-hotplate technology for the monitoring and control of indoor air quality (IAQ). GO powder is obtained by chemical exfoliation, dispersed in water and deposited via ink-jet printing onto a low power micro-hotplate. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) show the typical layered and wrinkled morphology of the GO. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Fourier transform infra-red (FTIR) spectroscopy indicate that the GO flakes possess a significant number of oxygen containing functional groups (epoxy, carbonyl, hydroxyl) extremely attractive for humidity detection. Electro-thermal characterisation of the micro-hotplates shows a thermal efficiency of 0.11 mW per °C, resulting in a sensor DC power consumption of only 2.75 mW at 50 °C. When operated in an isothermal mode, the sensor response is detrimentally affected by significant drift, hysteretic behaviour, slow response/recovery times and hence poor RH level discrimination. Conversely, a temperature modulation technique coupled with a differential readout methodology results in a significant reduction of the sensor drift, improved linear response with a sensitivity of 0.14 mV per %, resolution below 5%, and a maximum hysteresis of ±5%; response and recovery times equal to 189 ± 49 s and 89 ± 5 s, respectively. These performance parameters satisfy current IAQ monitoring requirements. We have thus demonstrated the effectiveness of integrating GO on a micro-hotplate CMOS-compatible platform enabling temperature modulation schemes to be easily applied in order to achieve compact, low power, low cost humidity IAQ monitoring.

  7. Analysis of processes in DC arc plasma torches for spraying that use air as plasma forming gas

    NASA Astrophysics Data System (ADS)

    Frolov, V.; Ivanov, D.; Toropchin, A.

    2014-11-01

    Developed in Saint Petersburg State Polytechnical University technological processes of air-plasma spraying of wear-resistant, regenerating, hardening and decorative coatings used in number of industrial areas are described. The article contains examples of applications of air plasma spraying of coatings as well as results of mathematical modelling of processes in air plasma torches for spraying.

  8. From ketones to esters by a Cu-catalyzed highly selective C(CO)-C(alkyl) bond cleavage: aerobic oxidation and oxygenation with air.

    PubMed

    Huang, Xiaoqiang; Li, Xinyao; Zou, Miancheng; Song, Song; Tang, Conghui; Yuan, Yizhi; Jiao, Ning

    2014-10-22

    The Cu-catalyzed aerobic oxidative esterification of simple ketones via C-C bond cleavage has been developed. Varieties of common ketones, even inactive aryl long-chain alkyl ketones, are selectively converted into esters. The reaction tolerates a wide range of alcohols, including primary and secondary alcohols, chiral alcohols with retention of the configuration, electron-deficient phenols, as well as various natural alcohols. The usage of inexpensive copper catalyst, broad substrate scope, and neutral and open air conditions make this protocol very practical. (18)O labeling experiments reveal that oxygenation occurs during this transformation. Preliminary mechanism studies indicate that two novel pathways are mainly involved in this process. PMID:25251943

  9. Air Quality Criteria for Ozone and Related Photochemical Oxidants (2006 Final)

    EPA Science Inventory

    Tropospheric or surface-level ozone (O3) is one of six major air pollutants regulated by National Ambient Air Quality Standards (NAAQS) under the U.S. Clean Air Act. As mandated by the Clean Air Act, the U.S. Environmental Protection Agency (EPA) must periodically review t...

  10. Anaerobic oxidation of methane: progress with an unknown process.

    PubMed

    Knittel, Katrin; Boetius, Antje

    2009-01-01

    Methane is the most abundant hydrocarbon in the atmosphere, and it is an important greenhouse gas, which has so far contributed an estimated 20% of postindustrial global warming. A great deal of biogeochemical research has focused on the causes and effects of the variation in global fluxes of methane throughout earth's history, but the underlying microbial processes and their key agents remain poorly understood. This is a disturbing knowledge gap because 85% of the annual global methane production and about 60% of its consumption are based on microbial processes. Only three key functional groups of microorganisms of limited diversity regulate the fluxes of methane on earth, namely the aerobic methanotrophic bacteria, the methanogenic archaea, and their close relatives, the anaerobic methanotrophic archaea (ANME). The ANME represent special lines of descent within the Euryarchaeota and appear to gain energy exclusively from the anaerobic oxidation of methane (AOM), with sulfate as the final electron acceptor according to the net reaction: CH(4) + SO(42-) ---> HCO(3-) + HS(-) + H(2)O. This review summarizes what is known and unknown about AOM on earth and its key catalysts, the ANME clades and their bacterial partners.

  11. Investigation of solution-processed bismuth-niobium-oxide films

    SciTech Connect

    Inoue, Satoshi; Ariga, Tomoki; Matsumoto, Shin; Onoue, Masatoshi; Miyasako, Takaaki; Tokumitsu, Eisuke; Shimoda, Tatsuya; Chinone, Norimichi; Cho, Yasuo

    2014-10-21

    The characteristics of bismuth-niobium-oxide (BNO) films prepared using a solution process were investigated. The BNO film annealed at 550°C involving three phases: an amorphous phase, Bi₃NbO₇ fluorite microcrystals, and Nb-rich cubic pyrochlore microcrystals. The cubic pyrochlore structure, which was the main phase in this film, has not previously been reported in BNO films. The relative dielectric constant of the BNO film was approximately 140, which is much higher than that of a corresponding film prepared using a conventional vacuum sputtering process. Notably, the cubic pyrochlore microcrystals disappeared with increasing annealing temperature and were replaced with triclinic β-BiNbO₄ crystals at 590°C. The relative dielectric constant also decreased with increasing annealing temperature. Therefore, the high relative dielectric constant of the BNO film annealed at 550°C is thought to result from the BNO cubic pyrochlore structure. In addition, the BNO films annealed at 500°C contained approximately 6.5 atm.% carbon, which was lost at approximately 550°C. This result suggests that the carbon in the BNO film played an important role in the formation of the cubic pyrochlore structure.

  12. Problems in Catalytic Oxidation of Hydrocarbons and Detailed Simulation of Combustion Processes

    NASA Astrophysics Data System (ADS)

    Xin, Yuxuan

    This dissertation research consists of two parts, with Part I on the kinetics of catalytic oxidation of hydrocarbons and Part II on aspects on the detailed simulation of combustion processes. In Part I, the catalytic oxidation of C1--C3 hydrocarbons, namely methane, ethane, propane and ethylene, was investigated for lean hydrocarbon-air mixtures over an unsupported Pd-based catalyst, from 600 to 800 K and under atmospheric pressure. In Chapter 2, the experimental facility of wire microcalorimetry and simulation configuration were described in details. In Chapter 3 and 4, the oxidation rate of C1--C 3 hydrocarbons is demonstrated to be determined by the dissociative adsorption of hydrocarbons. A detailed surface kinetics model is proposed with deriving the rate coefficient of hydrocarbon dissociative adsorption from the wire microcalorimetry data. In Part II, four fundamental studies were conducted through detailed combustion simulations. In Chapter 5, self-accelerating hydrogen-air flames are studied via two-dimensional detailed numerical simulation (DNS). The increase in the global flame velocity is shown to be caused by the increase of flame surface area, and the fractal structure of the flame front is demonstrated by the box-counting method. In Chapter 6, skeletal reaction models for butane combustion are derived by using directed relation graph (DRG) and DRG-aided sensitivity analysis (DRGASA), and uncertainty minimization by polynomial chaos expansion (MUM-PCE) mothodes. The dependence of model uncertainty is subjected to the completeness of the model. In Chapter 7, a systematic strategy is proposed to reduce the cost of the multicomponent diffusion model by accurately accounting for the species whose diffusivity is important to the global responses of the combustion systems, and approximating those of less importance by the mixture-averaged model. The reduced model is validated in an n-heptane mechanism with 88 species. In Chapter 8, the influence of Soret

  13. Post-launch lessons learned from the AIRS science data processing system

    NASA Astrophysics Data System (ADS)

    Manning, Evan M.; Friedman, Steven Z.; Chang, Albert Y.

    2003-11-01

    The AIRS Science Data Processing System, responsible for processing data from the 4-instrument AIRS suite, includes 14 separate executable programs and produces dozens of products. These executable programs and products conform to ECS standards for processing and archival at Goddard Earth Sciences DAAC. These standards include format and metadata constraints, and the PGE paradigm. Before launch the AIRS team defined and implemented all PGEs, created simulated test data, verified PGE performance with simulated and ground test data, and verified PGE integration within the GES DAAC processing and archiving systems. To support validation and continued software development, Jet Propulsion Laboratory (JPL) developed a limited shadow production system, and received all instrument data after launch. This in-house system was not designed to process and serve all data, but rather to run experimental versions of our software and to run additional non-deliverable programs in support of validation. These pre-flight preparations paid off, and the first year after launch has been very active for the AIRS science data processing group. Still, lessons can be learned from our experiences during our first year of data processing and post-launch software development. These experiences and observations may be useful to science seams developing future Earth observing instruments.

  14. Ubiquitous anaerobic ammonium oxidation in inland waters of China: an overlooked nitrous oxide mitigation process.

    PubMed

    Zhu, Guibing; Wang, Shanyun; Zhou, Leiliu; Wang, Yu; Zhao, Siyan; Xia, Chao; Wang, Weidong; Zhou, Rong; Wang, Chaoxu; Jetten, Mike S M; Hefting, Mariet M; Yin, Chengqing; Qu, Jiuhui

    2015-01-01

    Denitrification has long been regarded as the only pathway for terrestrial nitrogen (N) loss to the atmosphere. Here we demonstrate that large-scale anaerobic ammonium oxidation (anammox), an overlooked N loss process alternative to denitrification which bypasses nitrous oxide (N2O), is ubiquitous in inland waters of China and contributes significantly to N loss. Anammox rates in aquatic systems show different levels (1.0-975.9 μmol N m(-2) h(-1), n = 256) with hotspots occurring at oxic-anoxic interfaces and harboring distinct biogeochemical and biogeographical features. Extrapolation of these results to the China-national level shows that anammox could contribute about 2.0 Tg N yr(-1), which equals averagely 11.4% of the total N loss from China's inland waters. Our results indicate that a significant amount of the nitrogen lost from inland waters bypasses denitrification, which is important for constructing more accurate climate models and may significantly reduce potential N2O emission risk at a large scale. PMID:26610807

  15. Ubiquitous anaerobic ammonium oxidation in inland waters of China: an overlooked nitrous oxide mitigation process

    PubMed Central

    Zhu, Guibing; Wang, Shanyun; Zhou, Leiliu; Wang, Yu; Zhao, Siyan; Xia, Chao; Wang, Weidong; Zhou, Rong; Wang, Chaoxu; Jetten, Mike S. M.; Hefting, Mariet M.; Yin, Chengqing; Qu, Jiuhui

    2015-01-01

    Denitrification has long been regarded as the only pathway for terrestrial nitrogen (N) loss to the atmosphere. Here we demonstrate that large-scale anaerobic ammonium oxidation (anammox), an overlooked N loss process alternative to denitrification which bypasses nitrous oxide (N2O), is ubiquitous in inland waters of China and contributes significantly to N loss. Anammox rates in aquatic systems show different levels (1.0–975.9 μmol N m−2 h−1, n = 256) with hotspots occurring at oxic-anoxic interfaces and harboring distinct biogeochemical and biogeographical features. Extrapolation of these results to the China-national level shows that anammox could contribute about 2.0 Tg N yr−1, which equals averagely 11.4% of the total N loss from China’s inland waters. Our results indicate that a significant amount of the nitrogen lost from inland waters bypasses denitrification, which is important for constructing more accurate climate models and may significantly reduce potential N2O emission risk at a large scale. PMID:26610807

  16. Ubiquitous anaerobic ammonium oxidation in inland waters of China: an overlooked nitrous oxide mitigation process

    NASA Astrophysics Data System (ADS)

    Zhu, Guibing; Wang, Shanyun; Zhou, Leiliu; Wang, Yu; Zhao, Siyan; Xia, Chao; Wang, Weidong; Zhou, Rong; Wang, Chaoxu; Jetten, Mike S. M.; Hefting, Mariet M.; Yin, Chengqing; Qu, Jiuhui

    2015-11-01

    Denitrification has long been regarded as the only pathway for terrestrial nitrogen (N) loss to the atmosphere. Here we demonstrate that large-scale anaerobic ammonium oxidation (anammox), an overlooked N loss process alternative to denitrification which bypasses nitrous oxide (N2O), is ubiquitous in inland waters of China and contributes significantly to N loss. Anammox rates in aquatic systems show different levels (1.0-975.9 μmol N m-2 h-1, n = 256) with hotspots occurring at oxic-anoxic interfaces and harboring distinct biogeochemical and biogeographical features. Extrapolation of these results to the China-national level shows that anammox could contribute about 2.0 Tg N yr-1, which equals averagely 11.4% of the total N loss from China’s inland waters. Our results indicate that a significant amount of the nitrogen lost from inland waters bypasses denitrification, which is important for constructing more accurate climate models and may significantly reduce potential N2O emission risk at a large scale.

  17. Effects of Post-Pyrolysis Air Oxidation of Biomass Chars on Adsorption of Neutral and Ionizable Compounds.

    PubMed

    Xiao, Feng; Pignatello, Joseph J

    2016-06-21

    This study was conducted to understand the effects of thermal air oxidation of biomass chars experienced during formation or production on their adsorptive properties toward various compounds, including five neutral nonpolar and polar compounds and seven weak acids and bases (pKa = 3-5.2) selected from among industrial chemicals and the triazine and phenoxyacetic acid herbicide classes. Post-pyrolysis air oxidation (PPAO) at 400 °C of anoxically prepared wood and pecan shell chars for up to 40 min enhanced the mass-normalized adsorption at pH ∼ 7.4 of all test compounds, especially the weak acids and bases, by up to 100-fold. Both general and specific effects were identified. The general effect results from "reaming" of pores by the oxidative removal of pore wall matter and/or tarry deposits generated during the pyrolysis step. Reaming creates new surface area and enlarges nanopores, which helps relieve steric hindrance to adsorption. The specific effect results from creation of new acidic functionality that provides sites for the formation of very strong, charge-assisted hydrogen bonds (CAHB) with solutes having comparable pKa. The CAHB hypothesis was supported by competition experiments and the finding that weak acid anion adsorption increased with surface carboxyl content, despite electrostatic repulsion from the growing negative charge. The results provide insight into the effects of air oxidation on pollutant retention. PMID:27152745

  18. Basic properties of GaAs oxide generated by scanning probe microscope tip-induced nano-oxidation process

    NASA Astrophysics Data System (ADS)

    Okada, Yoshitaka; Iuchi, Yoshimasa; Kawabe, Mitsuo; Harris, James S.

    2000-07-01

    The basic properties of GaAs oxide generated by atomic force microscope (AFM) tip-induced nano-oxidation process have been investigated. The chemical analysis of the AFM tip-generated GaAs oxide was performed by using scanning microprobe x-ray photoelectron spectroscopy, and the main constituents of GaAs anodic oxide were determined to be Ga2O3 and As2O3. The electrical characterization showed that the electron transport across a GaAs oxide nanodot of ˜5.7 nm thickness, from a doped n+-Si tip into the n+-GaAs substrate follows the Fowler-Nordheim tunneling mechanism over a range of applied bias. Further, the tip-generated GaAs oxide nanodots were found to withstand moderate thermal treatments, but some volume reduction was observed.

  19. Short-Term Oxidation Studies on Nicrofer- 6025HT in Air at Elevated Temperatures for Advanced Coal Based Power Plants

    SciTech Connect

    Joshi, Vineet V.; Meier, Alan; Darsell, Jens T.; Nachimuthu, Ponnusamy; Bowden, Mark E.; Weil, K. Scott

    2013-04-01

    Several advanced air separation unit (ASU) designs being considered for use in coal gasification rely on the use of solid state mixed ionic and electronic conductors. Nicrofer-6025HT, a nickel-based alloy, has been identified as a potential manifold material to transport the hot gases into the ASUs. In the current study, isothermal oxidation tests were conducted on Nicrofer-6025HT in the temperature range of 700–900 °C for up to 24 h. The evolution of oxide scale was evaluated using SEM, XRD, and XPS. The composite surface oxide layer that formed consisted of an outer chromia-rich scale and an inner alumina scale. For the longer times at the higher temperatures evaluated, a NiCr2O4 spinel phase was located at the interface between the alumina and chromia. Based on the experimental results a four-step oxidation model was proposed.

  20. Narcotic effects of nitrous oxide and compressed air on memory and auditory perception.

    PubMed

    Fowler, B; White, P L; Wright, G R; Ackles, K N

    1980-03-01

    Three experiments were conducted to examine the effects of 35% N2 O (nitrous oxide) on human memory and auditory perception. In Experiment I, dichotic listening performance was found to be impaired. Experiment II used the same technique but was controlled for attenuation of sound transmission in the middle ear. No impairment was found. The perceptual effect found in Experiment I was peripheral, not central, and N2O did not impair short-term memory (STM). Experiment III used one-trial free recall of a word list. The shapes of the serial position curves were interpreted as indicating that N2O impairs long-term memory (LTM) but not STM. Experiment III provided no evidence, using cued recall, that the LTM deficit was due to impaired retrieval. Comparing these results with those for compressed air led to the conclusion that both N2O and hyperbaric nitrogen display an identical pattern of effects. A reason for the decrement found in some N2O STM studies may have been confounding the measurement of STM with that of LTM.