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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. 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.

  3. Thermodynamic and kinetic study of phenol degradation by a non-catalytic wet air oxidation process.

    PubMed

    Lefèvre, Sébastien; Boutin, Olivier; Ferrasse, Jean-Henry; Malleret, Laure; Faucherand, Rémy; Viand, Alain

    2011-08-01

    This work is dedicated to an accurate evaluation of thermodynamic and kinetics aspects of phenol degradation using wet air oxidation process. Phenol is a well known polluting molecule and therefore it is important having data of its behaviour during this process. A view cell is used for the experimental study, with an internal volume of 150 mL, able to reach pressures up to 30 MPa and temperatures up to 350°C. Concerning the thermodynamic phase equilibria, experimental and modelling results are obtained for different binary systems (water/nitrogen, water/air) and ternary system (water/nitrogen/phenol). The best model is the Predictive Soave Redlich Kwong one. This information is necessary to predict the composition of the gas phase during the process. It is also important for an implementation in a process simulation. The second part is dedicated to kinetics evaluation of the degradation of phenol. Different compounds have been detected using GC coupled with a MS. A kinetic scheme is deduced, taking into account the evolution of phenol, hydroquinones, catechol, resorcinol and acetic acid. The kinetic parameters are calculated for this scheme. These data are important to evaluate the evolution of the concentration of the different polluting molecules during the process. A simplified kinetic scheme, which can be easily implemented in a process simulation, is also determined for the direct degradation of phenol into H(2)O and CO(2). The Arrhenius law data obtained for the phenol disappearance are the following: k=1.8×10(6)±3.9×10(5)M(-1)s(-1) (pre-exponential factor) and E(a)=77±8 kJ mol(-1) (activation energy). PMID:21700312

  4. 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%.

  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%. PMID:26457966

  6. 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.

  7. 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. PMID:26164636

  8. 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.

  9. 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

    2016-05-01

    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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. DESTRUCTION OF AIR EMISSIONS USING CATALYTIC OXIDATION

    EPA Science Inventory

    The paper discusses key emission stream characteristics and hazardous air pollutant (HAP) characteristics that affect the applicability of catalytic oxidation as an air pollution control technique in which volatile organic compounds (VOCs) and vapor-phase air toxics in an air emi...

  18. 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.

  19. 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.

  20. ADVANCED OXIDATION PROCESS

    SciTech Connect

    Colin P. Horwitz; Terrence J. Collins

    2003-10-22

    The design of new, high efficiency and cleaner burning engines is strongly coupled with the removal of recalcitrant sulfur species, dibenzothiophene and its derivatives, from fuels. Oxidative desulfurization (ODS) wherein these dibenzothiophene derivatives are oxidized to their corresponding sulfoxides and sulfones is an approach that has gained significant attention. Fe-TAML{reg_sign} activators of hydrogen peroxide (TAML is Tetra-Amido-Macrocyclic-Ligand) convert in a catalytic process dibenzothiophene and its derivatives to the corresponding sulfoxides and sulfones rapidly at moderate temperatures (60 C) and ambient pressure. The reaction can be performed in both an aqueous system containing an alcohol (methanol, ethanol, or t-butanol) to solubilize the DBT and in a two-phase hydrocarbon/aqueous system where the alcohol is present in both phases and facilitates the oxidation. Under a consistent set of conditions using the FeBF{sub 2} TAML activator, the degree of conversion was found to be t-butanol > methanol > ethanol. In the cases of methanol and ethanol, both the sulfoxide and sulfone were observed while for t-butanol only the sulfone was detected. In the two-phase system, the alcohol may function as an inverse phase transfer agent. The oxidation was carried out using two different TAML activators. In homogeneous solution, approximately 90% oxidation of the DBT could be achieved using the prototype TAML activator, FeB*, by sonicating the solution at near room temperature. In bi-phasic systems conversions as high as 50% were achieved using the FeB* TAML activator and hydrogen peroxide at 100 C. The sonication method yielded only {approx}6% conversion but this may have been due to mixing.

  1. 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...

  2. 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...

  3. 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

  4. 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.

  5. Catalytic oxidative desulfurization of liquid hydrocarbon fuels using air

    NASA Astrophysics Data System (ADS)

    Sundararaman, Ramanathan

    Conventional approaches to oxidative desulfurization of liquid hydrocarbons involve use of high-purity, expensive water soluble peroxide for oxidation of sulfur compounds followed by post-treatment for removal of oxidized sulfones by extraction. Both are associated with higher cost due to handling, storage of oxidants and yield loss with extraction and water separation, making the whole process more expensive. This thesis explores an oxidative desulfurization process using air as an oxidant followed by catalytic decomposition of sulfones thereby eliminating the aforementioned issues. Oxidation of sulfur compounds was realized by a two step process in which peroxides were first generated in-situ by catalytic air oxidation, followed by catalytic oxidation of S compounds using the peroxides generated in-situ completing the two step approach. By this technique it was feasible to oxidize over 90% of sulfur compounds present in real jet (520 ppmw S) and diesel (41 ppmw S) fuels. Screening of bulk and supported CuO based catalysts for peroxide generation using model aromatic compound representing diesel fuel showed that bulk CuO catalyst was more effective in producing peroxides with high yield and selectivity. Testing of three real diesel fuels obtained from different sources for air oxidation over bulk CuO catalyst showed different level of effectiveness for generating peroxides in-situ which was consistent with air oxidation of representative model aromatic compounds. Peroxides generated in-situ was then used as an oxidant to oxidize sulfur compounds present in the fuel over MoO3/SiO2 catalyst. 81% selectivity of peroxides for oxidation of sulfur compounds was observed on MoO3/SiO2 catalyst at 40 °C and under similar conditions MoO3/Al2O3 gave only 41% selectivity. This difference in selectivity might be related to the difference in the nature of active sites of MoO3 on SiO2 and Al2O 3 supports as suggested by H2-TPR and XRD analyses. Testing of supported and bulk Mg

  6. Nitric oxide flow tagging in unseeded air.

    PubMed

    Dam, N; Klein-Douwel, R J; Sijtsema, N M; Meulen, J J

    2001-01-01

    A scheme for molecular tagging velocimetry is presented that can be used in air flows without any kind of seeding. The method is based on the local and instantaneous creation of nitric oxide (NO) molecules from N(2) and O(2) in the waist region of a focused ArF excimer laser beam. This NO distribution is advected by the flow and can be visualized any time later by laser-induced fluorescence in the gamma bands. The creation of NO is confirmed by use of an excitation spectrum. Two examples of the application of the new scheme for air-flow velocimetry are given in which single laser pulses are used for creation and visualization of NO. PMID:18033499

  7. Oxidation and Volatilization from Tantalum Alloy During Air Exposure

    SciTech Connect

    Smolik, Galen Richard; Petti, David Andrew; Schuetz, Stanley Thomas

    2000-10-01

    Tantalum alloys are one of the refractory metals with renewed consideration for high temperatures in fusion reactor applications. Tantalum alloys perform well in protective environments but are oxidized readily in gases containing higher oxygen levels. In addition, the radioactive isotope Ta-182 would be produced in tantalum and could be a significant contributor to dose if mobilized. Other isotopes of importance are produced from tungsten and hafnium. Mobilization of activated products during an accident with air ingress is therefore a safety issue. In this study, we measured the extent of oxidation and mobilization from tantalum alloy T-222 oxidized in flowing air between 500 and 1200 degrees C. This alloy nominally contains 10 wt% tungsten, 2.5 wt% hafnium and 0.01 wt% carbon. We found that the mobilization of Ta and Hf was closely linked to the occurrence of oxide spalling. These elements showed no migration from the test chamber. Some W was mobilized by volatilization as evidenced by transport from the chamber. Tungsten volatilization could occur primarily during initial stages of oxidation before the formation of an oxide scale impedes the process. The mobilization of Ta and W are presented in terms of the mass flux (g/m2-h) as a function of test temperature. These measurements along with specific designs, activation calculations, and accident scenarios provide information useful for dose calculations of future fusion devices.

  8. 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.

  9. Cutting Tool Wear After Pulsed Laser Processing in Air

    NASA Astrophysics Data System (ADS)

    Yares'ko, S. I.

    2014-01-01

    We have ascertained the influence of the oxide film formed on the surface of the laser-processed zone of tool steels by irradiation in air on the wear of the cutting tool. It has been shown that laser pulsed processing makes it possible to influence actively the process of its wear. The presence of the oxide film increases the wear stability of the tool in a wide range of cutting speeds, widens the range of cutting regimes in which its least wear is achieved, and minimizes the wear rate. Cutting regimes, in which the highest efficiency of the irradiated tool is achieved, have been established.

  10. ANALYSIS OF MODIFIED WET-AIR OXIDATION FOR SOIL DETOXIFICATION

    EPA Science Inventory

    The report presents the results of research on wet-air oxidation as a method for the destruction of hazardous wastes. For organics in the presence of large amounts of water, the water need not be vaporized during wet-air oxidation, an attractive characteristic for energy conserva...

  11. 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...

  12. 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.

  13. 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.

  14. Air pollution and circulating biomarkers of oxidative stress

    PubMed Central

    Staimer, Norbert; Vaziri, Nosratola D.

    2013-01-01

    Chemical components of air pollutant exposures that induce oxidative stress and subsequent inflammation may be partly responsible for associations of cardiovascular morbidity and mortality with airborne particulate matter and combustion-related pollutant gasses. However, epidemiologic evidence regarding this is limited. An exposure-assessment approach is to measure the oxidative potential of particle mixtures because it is likely that hundreds of correlated chemicals are involved in overall effects of air pollution on health. Oxidative potential likely depends on particle composition and size distribution, especially ultrafine particle concentration, and on transition metals and certain semivolatile and volatile organic chemicals. For health effects, measuring systemic oxidative stress in the blood is one feasible approach, but there is no universal biomarker of oxidative stress and there are many potential target molecules (lipids, proteins, DNA, nitric oxide, etc.), which may be more or less suitable for specific study goals. Concurrent with the measurement of oxidative stress, it is important to measure gene and/or protein expression of endogenous antioxidant enzymes because they can modify relations between oxidative stress biomarkers and air pollutants. Conversely, the expression and activities of these enzymes are modified by oxidative stress. This interplay will likely determine the observed effects of air pollutants on systemic inflammatory and thrombotic mediators and related clinical outcomes. Studies are needed to assess the reliability and validity of oxidative stress biomarkers, evaluate differences in associations between oxidative stress biomarkers and various pollutant measurements (mass, chemical components, and oxidative potential), and evaluate impacts of antioxidant responses on these relations. PMID:23626660

  15. 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.

  16. 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.

  17. 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.

  18. NEXAFS Study of Air Oxidation for Mg Nanoparticle Thin Film

    NASA Astrophysics Data System (ADS)

    Ogawa, S.; Murakami, S.; Shirai, K.; Nakanishi, K.; Ohta, T.; Yagi, S.

    2013-03-01

    The air oxidation reaction of Mg nanoparticle thin film has been investigated by Mg K-edge NEXAFS technique. It is revealed that MgO is formed on the Mg nanoparticle surfaces at the early stage of the air oxidation for Mg nanoparticle thin film. The simulation of NEXAFS spectrum using standard spectra indicates the existence of complex magnesium carbonates (x(MgCO3).yMg(OH2).z(H2O)) in addition to MgO at the early stage of the air oxidation.

  19. 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

  20. 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;…

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. OXIDANT AIR POLLUTION AND WORK PERFORMANCE OF CITRUS HARVEST LABOR

    EPA Science Inventory

    The project assesses the effect of photochemical oxidants on the work performance of twelve individual citrus pickers in the South Coast Air Basin of southern California. A model of the picker's decision problem is constructed in which oxidants influence the individual's picking ...

  9. 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…

  10. 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...

  11. Air Force electrochemical impregnation process results

    NASA Technical Reports Server (NTRS)

    Miller, L. E.

    1978-01-01

    The status of the Air Force Electrochemical program was reviewed. The performance characteristics of the system was attributed to the use of an electrochemical impregnation process. The electrode improvements, the prototype equipment designs, and the actual construction of a production facility are discussed.

  12. 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. PMID:24457302

  13. 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.

  14. 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.

  15. 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.

  16. Lithium oxides precipitation in nonaqueous Li-air batteries.

    PubMed

    Hou, Junbo; Yang, Min; Ellis, Michael W; Moore, Robert B; Yi, Baolian

    2012-10-21

    Lithium-air/oxygen battery is a rising star in the field of electrochemical energy storage as a promising alternative to lithium ion batteries. Nevertheless, this alluring system is still at its infant stage, and the breakthrough of lithium-air batteries into the energy market is currently constrained by a combination of scientific and technical challenges. Targeting at the air electrode in nonaqueous lithium-air batteries, this review attempts to summarize the knowledge about the fundamentals related to lithium oxides precipitation, which has been one of the vital and attractive aspects of the research communities of science and technology. PMID:22968061

  17. 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.

  18. Practical Aspects for Characterizing Air Oxidation of Graphite

    SciTech Connect

    Contescu, Cristian I; Azad, Samina; Miller, Doug; Lance, Michael J; Baker, Frederick S; Burchell, Timothy D

    2008-01-01

    The efforts for designing of a meaningful and acceptable standard test method for characterization of kinetic parameters of air oxidation of graphite helped identify several practical issues that must be considered for the development of such a test. Using standard size (and shape) specimens, large enough in size to accommodate the inherent local microstructure differences between graphite samples, resulted in non-uniform oxidation profiles and preferential binder oxidation; this was not expected based on the linearity of Arrhenius plots and the (large) values of activation energy. It was found that the transition between the regimes 1 and 2 of graphite oxidation occurs gradually, depending both on the oxidation temperature and rate of oxygen supply. Nevertheless, measuring oxidation rates obtained on standard size samples provides a basis for a meaningful comparison among materials, which may serve as much needed information for predictive models.

  19. Oxidation of oleic acid monolayers at air/liquid interfaces

    NASA Astrophysics Data System (ADS)

    Voss, L. F.; Bazerbashi, M. F.; Beekman, C. P.; Hadad, C. M.; Allen, H. C.

    2006-12-01

    Field studies of marine and continental aerosols find that fatty acid films form on aqueous tropospheric aerosols. Oxidation of the acyl chains is thought to be key to aerosol growth. Oxidation of oleic acid monolayers by ozone was studied to understand the fate of fat-coated aerosols from both fresh and salt water sources. Using vibrational sum frequency generation spectroscopy and reflection absorption infrared spectroscopy, we present a molecular-level investigation of fatty acid monolayers at the air-water and air- sodium chloride solution interface and explore reactions with atmospheric oxidants by these model systems. Using sum frequency generation spectroscopy coupled with a Langmuir trough, concurrent spectroscopic and thermodynamic data were collected to obtain a molecular picture of the monolayers. No substantial difference was observed between oxidation of monolayers spread on water and on 0.6 molar sodium chloride solutions. Results indicate that depending on the size of the aerosol and the extent of oxidation, the subsequent oxidation products may not remain at the surface of these films, but instead be dissolved in the aqueous sub-phase of the aerosol particle. Results also indicate that oxidation of oleic acid could produce monolayers containing species that have no oxidized acyl chains.

  20. 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

  1. Oxidation of oleic acid at air/liquid interfaces

    NASA Astrophysics Data System (ADS)

    Voss, Laura F.; Bazerbashi, Mohamad F.; Beekman, Christopher P.; Hadad, Christopher M.; Allen, Heather C.

    2007-03-01

    Oxidation of oleic acid monolayers by ozone was studied to understand the fate of fat-coated aerosols from both freshwater and saltwater sources. Oleic acid monolayers at the air/water interface and at the air/sodium chloride solution interface were investigated using surface-specific, broad-bandwidth, sum frequency generation spectroscopy. Complementary techniques of infrared reflection adsorption spectroscopy and surface pressure measurements taken during monolayer oxidation confirmed the sum frequency results. Using this nonlinear optical technique coupled with a Langmuir trough, concurrent spectroscopic and thermodynamic data were collected to obtain a molecular picture of the monolayers. No substantial difference was observed between oxidation of monolayers spread on water and on 0.6 M sodium chloride solutions. Results indicate that depending on the size of the aerosol and the extent of oxidation, the subsequent oxidation products may not remain at the surface of these films, but instead be dissolved in the aqueous subphase of the aerosol particle. Results also indicate that oxidation of oleic acid could produce monolayers containing species that have no oxidized acyl chains.

  2. Oxidation of oleic acid monolayers at air/liquid interfaces

    NASA Astrophysics Data System (ADS)

    Voss, Laura

    2008-03-01

    Field studies of marine and continental aerosols find that fatty acid films form on aqueous tropospheric aerosols. Oxidation of oleic acid monolayers by ozone was studied to understand the fate of fat-coated aerosols from both fresh and salt water sources. Using vibrational sum frequency generation spectroscopy and reflection absorption infrared spectroscopy, we present a molecular-level investigation of fatty acid monolayers at the air-water and air-sodium chloride solution interface and explore reactions with atmospheric oxidants by these model systems. Coupling sum frequency generation spectroscopy with a Langmuir trough, concurrent spectroscopic and thermodynamic data were collected to obtain a molecular picture of the monolayers. No substantial difference was observed between oxidation of monolayers spread on water and on 0.6 molar sodium chloride solutions. Results indicate that depending on the size of the aerosol and the extent of oxidation, the subsequent oxidation products may not remain at the surface of these films, but instead be dissolved in the aqueous sub-phase of the aerosol particle. Results also indicate that oxidation of oleic acid could produce monolayers containing species that have no oxidized acyl chains.

  3. 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...

  4. AIR QUALITY CRITERIA FOR OXIDES OF NITROGEN (Final, 1982)

    EPA Science Inventory

    This document is an evaluation and assessment of scientific information relative to determining the health and welfare effects associated with exposure to various concentrations of nitrogen oxides in ambient air. The document is not intended as a complete, detailed literature rev...

  5. 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...

  6. 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.

  7. 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.

  8. 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...

  9. 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.

  10. 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.

  11. 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. PMID:26393523

  12. 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

  13. Initial oxidation of brass induced by humidified air.

    PubMed

    Qiu, Ping; Leygraf, Christofer

    2011-11-15

    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/cm(2), 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

  14. 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.

  15. Surface-catalyzed air oxidation of hydrazines: Environmental chamber 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 fuel hydrazines were studied in a 6500-liter fluorocarbon-film chamber at 80 to 100 ppm concentrations. First-order rate constants for the reactions catalyzed by aluminum, water-damaged aluminum (Al/Al2O3), stainless steel 304L, galvanized steel and titanium plates with surface areas of 2 to 24 sq m were determined. With 23.8 sq m of Al/Al2O3 the surface-catalyzed air oxidation of hydrazine had a half-life of 2 hours, diimide (N2H2) was observed as an intermediate and traces of ammonia were present in the final product mixture. The Al/Al2O3 catalyzed oxidation of monomethylhydrazine yielded methyldiazine (HN = NCH3) as an intermediate and traces of methanol. Unsymmetrical dimethylhydrazine gave no detectable products. The relative reactivities of hydrazine, MMH and UDMH were 130 : 7.3 : 1.0, respectively. The rate constants for Al/Al2O3-catalyzed oxidation of hydrazine and MMH were proportional to the square of the surface area of the plates. Mechanisms for the surface-catalyzed oxidation of hydrazine and diimide and the formation of ammonia are proposed.

  16. Biodegradation of air-oxidized Illinois No. 6 coal

    SciTech Connect

    Linehan, J.C.; Fredrickson, J.K.; Wilson, B.W.; Bean, R.M.; Stewart, D.L.; Thomas, B.L.; Campbell, J.A.; Franz, J.A.

    1988-09-01

    We have found that Illinois No. 6 coal, after an air-oxidation pretreatment, can be substantially biodegraded by Penicillium sp. to a product largely soluble in dilute base. It is the purpose of this paper to describe the chemical nature of the biotreated Illinois No. 6 coal and to compare it with the corresponding material from leonardite biosolubilization. 12 refs., 7 figs., 3 tabs.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Prototypical experiments relating to air oxidation of Zircaloy-4 at high temperatures

    NASA Astrophysics Data System (ADS)

    Steinbrück, Martin

    2009-08-01

    The mechanism of the reaction between Zircaloy-4 and air at temperatures from 800 to 1500 °C was studied. Air attack under prototypical conditions with air ingress during a hypothetic severe nuclear reactor accident was investigated. Oxidation in air and in air and nitrogen-containing atmospheres leads to a major degradation of the cladding material. The main mechanism is the formation of zirconium nitride and its re-oxidation. Pre-oxidation in steam prevents air attack as long as the oxide scale is intact. Under steam/oxygen starvation conditions, the oxide scale is reduced and significant external nitride formation takes place. When modeling air ingress in severe accident computer codes, parabolic correlations for oxidation in air may be applied only for high temperatures (>1400 °C) and for pre-oxidized cladding (⩾1100 °C). Under all other conditions, faster, rather linear reaction kinetics should be applied.

  3. 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.

  4. 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.

  5. 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

  6. 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...

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. Oxidation and Volatilization from Tantalum Alloy T-222 During Air Exposure

    SciTech Connect

    Smolik, G.R.; Petti, D.A.; Sharpe, J.P.; Schuetz, S.T.

    2000-10-31

    Tantalum alloys are one of the refractory metals with renewed consideration for high temperatures in fusion reactor applications. Tantalum alloys perform well in protective environments but oxidized readily in gases containing higher oxygen levels. In addition, the radioactive isotope Ta-182 would be produced in tantalum and could be a significant contributor to dose if mobilized. Other isotopes of importance are produced from tungsten and hafnium. Mobilization of activated products during an accident with air ingress is therefore a safety issue. In this study, we measured the extent of oxidation and mobilization from tantalum alloy T-222 oxidized in flowing air between 500 and 1200 C. This alloy nominally contains 10 wt% tungsten, 2.5 wt% hafnium and 0.01 wt% carbon. We found that the mobilization of Ta and Hf was closely linked to the occurrence of oxide spalling. These elements showed no migration from the test chamber. Some W was mobilized by volatilization as evidenced by transport from the chamber. Tungsten volatilization could occur primarily during initial stages of oxidation before an oxide scale forms and impedes the process. The mobilization of Ta and W are presented in terms of the mass flux (g/m 2 -h) as a function of test temperature. These measurements along with specific designs, activation calculations, and accident scenarios provide information useful for dose calculations of future fusion devices.

  13. Oxidation and Volatilization from Tantalum Alloy T-222 During Air Exposure

    SciTech Connect

    Smolik, Galen Richard; Petti, David Andrew; Sharpe, John Phillip; Schuetz, Stanley Thomas

    2000-10-01

    Tantalum alloys are one of the refractory metals with renewed consideration for high temperatures in fusion reactor applications. Tantalum alloys perform well in protective environments but oxidized readily in gases containing higher oxygen levels. In addition, the radioactive isotope Ta-182 would be produced in tantalum and could be a significant contributor to dose if mobilized. Other isotopes of importance are produced from tungsten and hafnium. Mobilization of activated products during an accident with air ingress is therefore a safety issue. In this study, we measured the extent of oxidation and mobilization from tantalum alloy T-222 oxidized in flowing air between 500 and 1200°C. This alloy nominally contains 10 wt% tungsten, 2.5 wt% hafnium and 0.01 wt% carbon. We found that the mobilization of Ta and Hf was closely linked to the occurrence of oxide spalling. These elements showed no migration from the test chamber. Some W was mobilized by volatilization as evidenced by transport from the chamber. Tungsten volatilization could occur primarily during initial stages of oxidation before an oxide scale forms and impedes the process. The mobilization of Ta and W are presented in terms of the mass flux (g/m 2 -h) as a function of test temperature. These measurements along with specific designs, activation calculations, and accident scenarios provide information useful for dose calculations of future fusion devices

  14. 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).

  15. 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)

  16. 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

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  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, 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...

  7. 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...

  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 50.4 - 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...

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Alveolar macrophage cytokine response to air pollution particles: oxidant mechanisms

    PubMed Central

    Imrich, Amy; Ning, YaoYu; Lawrence, Joy; Coull, Brent; Gitin, Elena; Knutson, Mitchell; Kobzik, Lester

    2007-01-01

    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 cysteine (20mM), dimethyl thiourea (20 mM) and catalase (5 uM) 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 (H2O2 generated by glucose oxidase, 10 uM/hr), 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 H2O2. The metal chelator deferoxamine (DFO) strongly inhibited the interaction of the soluble fraction with H2O2 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 H2O2-dependent (catalase-sensitive) yet independent of iron (DFO-insensitive). In the presence of exogenous H2O2 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. PMID:17222881

  15. Complex utilization of snf processing wastes in air plasma of high-frequency torch discharge

    NASA Astrophysics Data System (ADS)

    Karengin, A. G.; Karengin, A. A.; Podgornaya, O. D.; Shlotgauer, E. E.

    2014-10-01

    We present results of complex spent nuclear fuel wastes utilization process in air plasma of high-frequency torch discharge in form of dispersed water-organic compositions. We demonstrate the possibility to apply magnetic separation for effective extraction of obtained dispersed solid products including magnetic iron oxide from water suspension.

  16. 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

  17. 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.

  18. 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...

  19. 40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 2 2010-07-01 2010-07-01 false National primary ambient air quality... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.4 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). Link to...

  20. AIR QUALITY CRITERIA FOR PARTICULATE MATTER AND SULFUR OXIDES (Final, 1982)

    EPA Science Inventory

    Particulate matter and sulfur oxides are two 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 the scienti...

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. Air trichloroethylene oxidation in a corona plasma-catalytic reactor

    NASA Astrophysics Data System (ADS)

    Masoomi-Godarzi, S.; Ranji-Burachaloo, H.; Khodadadi, A. A.; Vesali-Naseh, M.; Mortazavi, Y.

    2014-08-01

    The oxidative decomposition of trichloroethylene (TCE; 300 ppm) by non-thermal corona plasma was investigated in dry air at atmospheric pressure and room temperature, both in the absence and presence of catalysts including MnOx, CoOx. The catalysts were synthesized by a co-precipitation method. The morphology and structure of the catalysts were characterized by BET surface area measurement and Fourier Transform Infrared (FTIR) methods. Decomposition of TCE and distribution of products were evaluated by a gas chromatograph (GC) and an FTIR. In the absence of the catalyst, TCE removal is increased with increases in the applied voltage and current intensity. Higher TCE removal and CO2 selectivity is observed in presence of the corona and catalysts, as compared to those with the plasma alone. The results show that MnOx and CoOx catalysts can dissociate the in-plasma produced ozone to oxygen radicals, which enhances the TCE decomposition.

  6. Wet air oxidation of solid waste made of polymers

    SciTech Connect

    Krisner, E.; Ambrosio, M.; Massiani, C.

    2000-03-01

    Wet air oxidation was attempted on synthetic (mixture of plastics of various compositions) and natural (cellulose substances) solid polymers. The temperature was maintained at 270 C and the oxygen pressure varied from 0 to 2 MPa (from understoichiometric conditions to oxygen excess). No valorizable compounds were found, even in runs carried out under an oxygen deficit. Suitable conditions for the total destruction of the initial polymers were temperatures above 270 C, an excess of oxygen, and a residence time of less than 1 h. Only such degradable compounds as acetic and benzoic acids are found at low concentrations. Formation of chlorine and gaseous hydrochloric acid can be limited by adding CaCO{sub 3} as a neutralizing agent.

  7. 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.

  8. In-flight oxidation of aluminum in the twin-wire electric arc process

    NASA Astrophysics Data System (ADS)

    Guillen, Donna Post; Williams, Brian G.

    2006-03-01

    This paper examines the in-flight oxidation of aluminum sprayed in air using the twin-wire electric arc (TWEA) thermal spray process. Aerodynamic shear at the droplet surface increases the amount of in-flight oxidation by promoting entrainment of the surface oxides within the molten droplet and continually exposing fresh fluid available for oxidation. Mathematical predictions herein confirm experimental measurements that reveal an elevated, nearly constant surface temperature (˜2273 K) of the droplets during flight. The calculated oxide volume fraction of a “typical” droplet with internal circulation compares favorably to the experimentally determined oxide content (3.3 12.7%) for a typical TWEA-sprayed aluminum coating sprayed onto a room temperature substrate. It is concluded that internal circulation within the molten aluminum droplet is a significant source of oxidation. This effect produces an oxide content nearly two orders of magnitude larger than that of a droplet without continual oxidation.

  9. 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.

  10. Air contamination with nitric oxide: effect on exhaled nitric oxide response.

    PubMed

    Therminarias, A; Flore, P; Favre-Juvin, A; Oddou, M F; Delaire, M; Grimbert, F

    1998-03-01

    This study examines the response of exhaled nitric oxide (NO) concentration (ECNO) and quantity of exhaled NO over time (EVNO) in 10 healthy subjects breathing into five polyethylene bags, one in which synthetic air was free of NO and four in which NO was diluted to concentrations of 20 +/- 0.6, 49 +/- 0.8, 98 +/- 2, and 148 +/- 2 ppb, respectively. Each subject was connected to each bag for 10 min at random. Minute ventilation and ECNO were measured continuously, and EVNO was calculated continuously. ECNO and EVNO values were significantly higher for an inhaled NO concentration of 20 ppb than for NO-free air. Above 20 ppb, ECNO and EVNO increased linearly with inhaled NO concentration. It is reasonable to assume that a share of the quantity of inspired NO over time (InspVNO) because of air contamination by pollution is rejected by the ventilatory pathway. Insofar as InspVNO does not affect endogenous production or the metabolic fate of NO in the airway, this share may be estimated as being approximately one third of InspVNO, the remainder being taken by the endogenous pathway. Thus, air contamination by the NO resulting from pollution greatly increases the NO response in exhaled air. PMID:9517592

  11. 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.

  12. Increased amount of nitric oxide in exhaled air of asthmatics.

    PubMed

    Alving, K; Weitzberg, E; Lundberg, J M

    1993-10-01

    The presence of nitric oxide (NO) in the exhaled air of humans has recently been described. We wanted to assess at what level exhaled NO originates in normal airways, and to determine whether airway inflammation induces changes in the levels of exhaled NO. Exhaled NO was continuously measured by chemiluminescence technique during normal tidal breathing through the nose or mouth, with a detection limit of 1 part per billion (ppb). Twelve control subjects were compared to eight patients with mild atopic asthma and rhinitis caused by occupational allergen. In control subjects, the major part of NO in exhaled air (up to 30 ppb) seemed to originate in the nasal airways, with only minor contribution from the lower airways and the oral cavity. However, in mild asthmatics, the level of exhaled NO during oral breathing, indicating the involvement of the lower airways, was increased 2-3 fold. Since increased production of NO in the lower airways may involve activated macrophages or neutrophils, we suggest that exhaled NO may be used to instantly monitor ongoing bronchial inflammation, at least when involving inducible NO synthase. PMID:7507065

  13. 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.

  14. 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

  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. Hybrid process for nitrogen oxides reduction

    SciTech Connect

    Epperly, W.R.; Sprague, B.N.

    1991-09-10

    This patent describes a process for reducing the nitrogen oxide concentration in the effluent from the combustion of a carbonaceous fuel. It comprises introducing into the effluent a first treatment agent comprising a nitrogenous composition selected from the group consisting of urea, ammonia, hexamethylenetetramine, ammonium salts of organic acids, 5- or 6-membered heterocyclic hydrocarbons having at least one cyclic nitrogen, hydroxy amino hydrocarbons, NH{sub 4}-lignosulfonate, fur-furylamine, tetrahydrofurylamine, hexamethylenediamine, barbituric acid, guanidine, guanidine carbonate, biguanidine, guanylurea sulfate, melamine, dicyandiamide, biuret, 1.1{prime}-azobisformamide, methylol urea, methylol urea-urea condensation product, dimethylol urea, methyl urea, dimethyl urea, calcium cyanamide, and mixtures thereof under conditions effective to reduce the nitrogen oxides concentration and ensure the presence of ammonia in the effluent; introducing into the effluent a second treatment agent comprising an oxygenated hydrocarbon at an effluent temperature of about 500{degrees} F. to about 1600{degrees} F. under conditions effective to oxidize nitric oxide in the effluent to nitrogen dioxide and ensure the presence of ammonia at a weight ratio of ammonia to nitrogen dioxide of about 1:5 to about 5:1; and contacting the effluent with an aqueous scrubbing solution having a pH of 12 or lower under conditions effective to cause nitrogen dioxide to be absorbed therein.

  17. Alternative materials for solid oxide fuel cells: Factors affecting air-sintering of chromite interconnections

    SciTech Connect

    Chick, L.A.; Bates, J.L.

    1992-07-01

    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. Another objective is to develop synthesis and fabrication processes for these materials whereby they can be consolidated in air into SOFCs. The approach is to (1) develop modifications of the current, state-of-the-art materials used in SOFCs, (2) minimize the number of cations used in the SOFC materials to reduce potential deleterious interactions, (3) improve thermal, electrical, and electrochemical properties, (4) develop methods to synthesize both state-of-the-art and alternative materials for the simultaneous fabrication and consolidation in air of the interconnections and electrodes with the solid electrolyte, and (5) understand electrochemical reactions at materials interfaces and the effects of component compositions and processing on those reactions.

  18. 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.

  19. 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.

  20. Highly enantioselective oxidative couplings of 2-naphthols catalyzed by chiral bimetallic oxovanadium complexes with either oxygen or air as oxidant.

    PubMed

    Guo, Qi-Xiang; Wu, Zhi-Jun; Luo, Zhi-Bin; Liu, Quan-Zhong; Ye, Jian-Liang; Luo, Shi-Wei; Cun, Lin-Feng; Gong, Liu-Zhu

    2007-11-14

    The chiral bimetallic oxovanadium complexes have been designed for the enantioselective oxidative coupling of 2-naphthols bearing various substituents at C6 and/or C7. The chirality transferring from the amino acid to the axis of the biphenyl in oxovanadium complexes 2 was found to occur with the use of UV and CD spectra and DFT calculation. The homo-coupling reaction with oxygen as the oxidant was promoted by 5 mol % of an oxovanadium complex derived from L-isoleucine and achiral biphenol to afford binaphthols in nearly quantitative yields with high enantioselectivities of up to 98% ee. An oxovanadium complex derived from L-isoleucine and H8-binaphthol is highly efficient at catalyzing the air-oxidized coupling of 2-naphthols with excellent enantioselectivities of up to 97% ee. 51V NMR study shows that the oxovanadium complexes have two vanadium(V) species. Kinetic studies, the cross-coupling reaction, and HRMS spectral studies on the reaction have been carried out and illustrate that two vanadium(V) species are both involved in catalysis and that the coupling reaction undergoes a radical-radical mechanism in an intramolecular manner. Quantum mechanical calculations rationalize the importance of the cooperative effects of the axial chirality matching S-amino acids on the stereocontrol of the oxidative coupling reaction. The application of the transformation in the preparation of chiral ligands and conjugated polymers confirms the importance of the current process in organic synthesis. PMID:17956093

  1. 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.

  2. 76 FR 46083 - Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Sulfur

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-01

    ...This proposed rule is being issued as required by a consent decree governing the schedule for completion of this review of the air quality criteria and the secondary national ambient air quality standards (NAAQS) for oxides of nitrogen and oxides of sulfur. Based on its review, EPA proposes to retain the current nitrogen dioxide (NO2) and sulfur dioxide (SO2) secondary......

  3. Laser processing of polytetrafluoroethylene (Teflon) in air

    NASA Astrophysics Data System (ADS)

    Wang, Z. B.; Hong, Ming Hui; Lu, Yong Feng; Chong, Tow Chong

    2003-02-01

    Teflon, polytetrafluorethylene (PTFE), is an important material in bioscience and medical application due to its special characteristics (non-flammable, anti-adhesive, heat-resistant and bio-compatible). The advantages of ultrashort laser processing of Teflon include a minimal thermal penetration region and low processing temperatures, precision removal of material, and good-quality feature definition. In this paper, laser processing of Teflon by Ti:Sapphire femtosecond laser (780 nm, 110 fs), Nd:YAG laser (532 nm, 7 ns) and CO2 laser (10.6 μm, 10 μs) has been investigated. For femtosecond laser processing, clear ablation takes place and provides high-quality groove on Teflon surface. Both the groove depth and the width increase as the laser fluence increase, and decrease almost linearly as the scanning speed increase for laser fluence below 5.0 J/cm2. For Nd:YAG processing, Teflon surface roughness is improved but no clean ablation is accessible, which makes it difficult to micromachine Teflon by Nd:YAG laser. For CO2 laser processing, laser-induced bumps were formed on Teflon surface with controlled laser parameters. The physics mechanisms for different pulse duration laser processing of Teflon are also discussed.

  4. 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. PMID:26273851

  5. 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.

  6. Air separation by the Moltox process. Interim final report

    SciTech Connect

    Erickson, D.C.

    1981-04-01

    Results are described of a development program on a new and energy-saving process for air separation. The Moltox process involves reversibly reacting oxygen in air with a recirculating salt solution, such that oxygen is extracted without depressurizing the remaining nitrogen. Energy savings of approximately 50% are indicated for this process compared to conventional cryogenic air separation. The development program consisted of design, construction, and operation of a 6 liter/minute pilot plant; optimization of the process flowsheet through computer modelling; investigation of engineering aspects of the process including corrosion, safety, and NO/sub x/ generation; and an economic comparison to conventional cryogenic practice. All objectives were satisfactorily achieved except for continuous operation of the pilot plant, and the modifications necessary to achieve that have been identified. Economically the Moltox process shows a substantial advantage over large scale cryogenic plants which are powered by fuel vice electricity.

  7. 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.

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

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 2 2010-07-01 2010-07-01 false National secondary ambient air quality standard for sulfur oxides (sulfur dioxide). 50.5 Section 50.5 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS §...

  9. 78 FR 54813 - Approval and Promulgation of Air Quality Implementation Plans; Maine; Oxides of Nitrogen...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-06

    ... AGENCY 40 CFR Parts 52 Approval and Promulgation of Air Quality Implementation Plans; Maine; Oxides of... comment period on our proposed Approval and Promulgation of Air Quality Implementation Plans; Maine... materials are available either electronically in www.regulations.gov or in hard copy at Air Quality...

  10. 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

  11. 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.

  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. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Nitrogen and carbon oxides chemistry in the HRS retorting process

    SciTech Connect

    Reynolds, J.G.

    1993-11-12

    The HRS Oil Shale Retort process consists of a pyrolysis section which converts kerogen of the shale to liquid and gaseous products, and a combustion section which burns residual carbon on the shale to heat the process. Average gas concentrations of selected gas phase species were determined from data measured at several placed on the combustion system of the Lawrence Livermore National Laboratory Hot-Recycled-Solids Retort Pilot Plant for representative rich and lean shale runs. The data was measured on-line and in real time by on-line meters (CO{sub 2}, CO, O{sub 2}), mass spectrometry (CO{sub 2}, O{sub 2}, H{sub 2}O, NO, CH{sub 4}, SO{sub 2}, N{sub 2} and Ar), and Fourier transform infrared spectroscopy (CO{sub 2}, CO, H{sub 2}O, NO, N{sub 2}O, NO{sub 2}, CH{sub 4}, SO{sub 2}, NH{sub 3}, and HCN). For both the rich and leans shale runs, the Lift-Pipe Combustor (LFT) exhibited gas concentrations (sampled at the exit of the LFT) indicative of incomplete combustion and oxidation; the Delayed-Fall Combustor (DFC) exhibited gas concentrations (sampled at the annulus and the exit of the DFC) indicative of much more complete combustion and oxidation. The Fluidized-Bed Combustor exhibited gas concentrations which were controlled to a large extent by the injection atmosphere of the FBC. High levels of nitrogen oxides and low levels of CO were detected when full air injection was used, while high levels of CO and low levels of nitrogen-oxides were detected with partial N{sub 2} injection. Sequential sampling limitations and nitrogen balances are also discussed.

  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, 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...

  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, 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...

  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, 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...

  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. 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.

  4. 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.

  5. 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.

  6. Reducing phosphine after the smoking process using an oxidative treatment.

    PubMed

    Nota, G; Naviglio, D; Romano, R; Ugliano, M; Sabia, V

    2000-02-01

    This article gives a description of the setup in a laboratory of a pilot system to reduce phosphine following the smoking process of foodstuffs. At present, this fumigant is released into the atmosphere and causes serious damage to the environment due to its transformation into aggressive compounds. However, phosphine may prove a good alternative to methyl bromide, which will legally be used as a fumigant until the year 2002, provided it is made inert after the smoking process and transformed into nontoxic and easily disposable substances. Oxidant solutions containing potassium permanganate or potassium bichromate in suitable concentrations proved moderately effective in reducing phosphine. The addition of traces of silver nitrate as a catalyst to the oxidant solutions increased the efficiency in reducing the fumigant, although not completely. Thus it was necessary to use a recycling system to decontaminate air from phosphine, as such an apparatus ensures the complete reduction of phosphine. The mathematical function describing how the concentration of phosphine varies in the smoking chamber also makes it possible to estimate the time necessary to reduce a phosphine concentration from any initial value to a fixed final value. PMID:10691669

  7. 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.

  8. 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.

  9. 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.

  10. PHOTOCHEMICAL OXIDANT AIR POLLUTION EFFECTS ON A MIXED CONIFER FOREST FOREST ECOSYSTEM - A PROGRESS REPORT

    EPA Science Inventory

    Since 1972, twelve scientists representing several research disciplines have collaborated in integrated studies to determine the chronic effects of photochemical oxidant air pollutants on a western mixed conifer forest ecosystem. An enormous amount of data has been collected, des...

  11. 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.

  12. 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.

  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. PMID:27482771

  14. 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…

  15. 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

  16. 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...

  17. AIR QUALITY CRITERIA FOR OXIDES OF NITROGEN (External Review Draft, 1991)

    EPA Science Inventory

    The revised air quality criteria document for oxides of nitrogen (NOx) reviews and evaluates the scientific information on the health and welfare effects associated with exposure to concentrations of NO2 found in ambient air. Although the document is not intended to be an exhaust...

  18. 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.

  19. DEVELOPMENT OF TRANSITION METAL OXIDE-ZEOLITE CATALYSTS TO CONTROL CHLORINATED VOC AIR EMISSIONS

    EPA Science Inventory

    The paper discusses the development of transition metal oxide (TMO)-zeolite oxidation catalysts to control chlorinated volatile organic compound (CVOC) air emissions. esearch has been initiated to enhance the utility of these catalysts by the development of a sorption-catalyst sy...

  20. Heterogeneous photochemical reactions of a propylene-nitrogen dioxide-metal oxide-dry air system

    NASA Astrophysics Data System (ADS)

    Takeuchi, Koji; Ibusuki, Takashi

    Photochemical reactions of a C 3H 6-NO 2-air system in the presence of metal oxide were investigated. The metal oxides showing strong photooxidation activity were found to be n-type semiconductor oxides with the energy band gap around 3 eV. Formation of cyano-compounds (HCN and CH 3CN) was also observed and the activity can be explained in terms of the adsorptivity of NO onto metal oxides. Coalfired fly ash as a model of mixed metal oxides was also examined and their photocatalytic action was discussed.

  1. AIR QUALITY CRITERIA FOR OXIDES OF NITROGEN (Final, 1993)

    EPA Science Inventory

    This criteria document focuses on a review and assessment of the effects on human health and welfare of the nitrogen oxides, nitric oxide (NO) and nitrogen dioxide (NO2), and the related compounds, nitrites, nitrates, nitrogenous acids, and nitrosamines. Although the emphasis is ...

  2. 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...

  3. Removal of estrogens by electrochemical oxidation process.

    PubMed

    Cong, Vo Huu; Iwaya, Sota; Sakakibara, Yutaka

    2014-06-01

    Treatments of estrogens such as Estrone (E1), Estradiol (E2) and Ethinylestradiol (EE2) were conducted using an electrolytic reactor equipped with multi-packed granular glassy carbon electrodes. Experimental results showed that E1, E2 and EE2 were oxidized in the range of 0.45-0.85 V and were removed through electro-polymerization. Observed data from continuous experiments were in good agreement with calculated results by a mathematical model constructed based on mass transfer limitation. In continuous treatment of trace estrogens (1 μg/L), 98% of E1, E2 and EE2 were stably removed. At high loading rate (100 μg/L), removal efficiency of E1 was kept around 74%-88% for 21 days, but removal efficiency reduced due to passivation of electrodes. However, removal efficiency was recovered after electrochemical regeneration of electrodes in presence of ozone. Electric energy consumption was observed in the range of 1-2 Wh/m(3). From these results, we concluded that the present electrochemical process would be an alternative removal of estrogens. PMID:25079848

  4. 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…

  5. Review of solution-processed oxide thin-film transistors

    NASA Astrophysics Data System (ADS)

    Kim, Si Joon; Yoon, Seokhyun; Kim, Hyun Jae

    2014-02-01

    In this review, we summarize solution-processed oxide thin-film transistors (TFTs) researches based on our fulfillments. We describe the fundamental studies of precursor composition effects at the beginning in order to figure out the role of each component in oxide semiconductors, and then present low temperature process for the adoption of flexible devices. Moreover, channel engineering for high performance and reliability of solution-processed oxide TFTs and various coating methods: spin-coating, inkjet printing, and gravure printing are also presented. The last topic of this review is an overview of multi-functional solution-processed oxide TFTs for various applications such as photodetector, biosensor, and memory.

  6. Nanoscale metal oxide and supported metal catalysts for Li-air battery

    NASA Astrophysics Data System (ADS)

    Huang, Kan

    The dissertation work focuses on research and development of durable nanoscale catalysts and supports for rechargeable Li-air batteries that use aqueous catholytes. Transition metal oxides, TiO2 and Nb2 O5 in particular, were prepared from a sol-gel process in the form of nanocoatings (5˜50 nm) on carbon nanotubes (CNTs) and studied as catalyst supports. Carbon doping in the oxides and post annealing significantly increased their electronic conductivity. Pt catalyst on the support with TiO 2 (Pt/c-TiO2/CNTs) showed a much better oxygen reduction reaction (ORR) activity than a commercial Pt on carbon black (Pt/C). Negligible loss (< 3%) in ORR activity was found in Pt/c-TiO2/CNTs as compared to more than 50% loss in Pt/C, demonstrating a significantly improved durability in the developed catalysts. However, Pt/c-Nb2O5/CNTs was found to be worse in ORR activity and durability, suggesting that c-Nb 2O5/CNTs may not be a good support. CNTs have fibrous shape and would provide a unique porous structure as electrode. Their buckypapers were made and used to support catalysts of Pt and IrO2 in the cathodes of Li-air batteries with sulfuric acid catholyte. At low Pt loading (5 wt.%) without IrO2 on the buckypaper cathode, the Li-air cell achieved a discharging capacity of 306 mAh/g and a specific energy of 1067 Wh/kg at 0.2 mA/cm2. A significant charge overpotential reduction (˜ 0.3 V) was achieved when IrO2 was also used to form a bifunctional catalyst with Pt on the buckypapers. The round trip efficiency was increased from 72% to 81% with the bifunctional cathode, demonstrating a higher energy conversion efficiency.

  7. Materials, design and processing of air encapsulated MEMS packaging

    NASA Astrophysics Data System (ADS)

    Fritz, Nathan T.

    This work uses a three-dimensional air cavity technology to improve the fabrication, and functionality of microelectronics devices, performance of on-board transmission lines, and packaging of micro-electromechanical systems (MEMS). The air cavity process makes use of the decomposition of a patterned sacrificial polymer followed by the diffusion of its by-products through a curing polymer overcoat to obtain the embedded air structure. Applications and research of air cavities have focused on simple designs that concentrate on the size and functionality of the particular device. However, a lack of guidelines for fabrication, materials used, and structural design has led to mechanical stability issues and processing refinements. This work investigates improved air gap cavities for use in MEMS packaging processes, resulting in fewer fabrication flaws and lower cost. The identification of new materials, such as novel photo-definable organic/inorganic hybrid polymers, was studied for increased strength and rigidity due to their glass-like structure. A novel epoxy polyhedral oligomeric silsesquioxane (POSS) material was investigated and characterized for use as a photodefineable, permanent dielectrics with improved mechanical properties. The POSS material improved the air gap fabrication because it served as a high-selectivity etch mask for patterning sacrificial materials as well as a cavity overcoat material with improved rigidity. An investigation of overcoat thickness and decomposition kinetics provided a fundamental understanding of the properties that impart mechanical stability to cavities of different shape and volume. Metallization of the cavities was investigated so as to provide hermetic sealing and improved cavity strength. The improved air cavity, wafer-level packages were tested using resonator-type devices and chip-level lead frame packaging. The air cavity package was molded under traditional lead frame molding pressures and tested for mechanical

  8. 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.

  9. Effect of Process Variables During the Head-End Treatment of Spent Oxide Fuel

    SciTech Connect

    K.J. Bateman; C.D. Morgan; J.F. Berg; D.J. Brough; P.J. Crane; D.G. Cummings; J.J. Giglio; M.W. Huntley; M.J. Rodriquez; J.D. Sommers; R.P. Lind; D.A. Sell

    2006-08-01

    The development of a head-end processing step for spent oxide fuel that applies to both aqueous and pyrometallurgical technologies is being performed by the Idaho National Laboratory, the Oak Ridge National Laboratory, and the Korean Atomic Energy Research Institute through a joint International Nuclear Energy Research Initiative. The processing step employs high temperatures and oxidative gases to promote the oxidation of UO2 to U3O8. Potential benefits of the head-end step include the removal or reduction of fission products as well as separation of the fuel from cladding. The effects of temperature, pressure, oxidative gas, and cladding have been studied with irradiated spent oxide fuel to determine the optimum conditions for process control. Experiments with temperatures ranging from 500oC to 1250oC have been performed on spent fuel using either air or oxygen gas for the oxidative reaction. Various flowrates and applications have been tested with the oxidative gases to discern the effects on the process. Tests have also been performed under vacuum conditions, following the oxidation cycle, at high temperatures to improve the removal of fission products. The effects of cladding on fission product removal have also been investigated with released fuel under vacuum and high temperature conditions. Results from these experiments will be presented as well as operating conditions based on particle size and decladding characteristics.

  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, 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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.

  16. 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.

  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 %. PMID:27115288

  18. 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. PMID:26970442

  19. Make phthalic anhydride with low air ratio process

    SciTech Connect

    Verde, L.; Nari, A.

    1984-11-01

    A new process for the production of phthalic anhydride from o-xylene has been developed by Alusuisse Italia S.p.A. and is now being implemented in one of the two large reactors (15,500 tubes each) of Ftalital, Division of Alusuisse Italia. The main advantages of the new technology in comparison with the best current technology (the low energy process are essentially the following: An increase of the catalyst productivity by more than 40% A reduction of weight air/o-xylene ratio from 20:1 to 9.5:1 (corresponding to an increase in o-xylene concentration in air from 65 g/Nm/sup 3/ to 134 g/Nm/sup 3/); A consequent reduction of both capital investment and energy consumption, which contribute to reducing the transfer price of production of phthalic anhydride by more than US$40 per metric ton, at the present prevailing raw material and utilities costs. The new technology at low air ratio (LAR Process) was predicted upon the development of a new catalyst formulation specifically adapted to the purpose. This required about two years of research work in laboratories and pilot facilities of Alusuisse Italia.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Influence of fission products on ruthenium oxidation and transport in air ingress nuclear accidents

    NASA Astrophysics Data System (ADS)

    Vér, N.; Matus, L.; Kunstár, M.; Osán, J.; Hózer, Z.; Pintér, A.

    2010-01-01

    In separate effect tests at 1000-1200 °C Ru oxidation rate and content of Ru in escaping air flow have been studied with special emphasis on effects of other fission product elements on the Ru oxidation and transport. The results showed that in the decreasing temperature section (1100-600 °C) most of the RuO3 and RuO4 (≈95%) decomposed and formed RuO2 crystals; while the partial pressure of RuO4 in the escaping air was in the range of 10-6 bar. The re-evaporation of deposited RuO2 resulted in about 10-6 bar partial pressure in the outlet gas as well. Measurements demonstrated the importance of surface quality in the decreasing temperature area on the heterogeneous phase decomposition of ruthenium oxides to RuO2. On the other hand water or molybdenum oxide vapour in air appears to decrease the surface catalyzed decomposition of RuOx to RuO2 and increases RuO4 concentration in the escaping air. High temperature reaction with caesium changed the form of the released ruthenium and caused a time delay in appearance of maximum concentration of ruthenium oxides in the ambient temperature escaping gas, while reaction with barium and rare earth oxides extended Ru escape from the high temperature area.

  5. 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.

  6. Catalyst and process for oxidizing hydrogen sulfide

    SciTech Connect

    Hass, R.H.; Fullerton; Ward, J.W.; Yorba, L.

    1984-04-24

    Catalysts comprising bismuth and vanadium components are highly active and stable, especially in the presence of water vapor, for oxidizing hydrogen sulfide to sulfur or SO/sub 2/. Such catalysts have been found to be especially active for the conversion of hydrogen sulfide to sulfur by reaction with oxygen or SO/sub 2/.

  7. 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.

  8. 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.

  9. 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 ...

  10. Conversion of Sulfur by Wet Oxidation in the Bayer Process

    NASA Astrophysics Data System (ADS)

    Liu, Zhanwei; Li, Wangxing; Ma, Wenhui; Yin, Zhonglin; Wu, Guobao

    2015-08-01

    In this paper, the effects of temperature, oxidation time, and oxygen concentration on the conversion of sulfur by wet oxidation in the Bayer process were investigated at length. The results show that active sulfur S2- and S2O3 2- in sodium aluminate solution can be converted completely by wet oxidation during the digestion process, thus the effects of S2- and S2O3 2- on alumina product quality are eliminated; increased temperature, oxidation time, and oxygen concentration are conducive to conversion of S2- and S2O3 2-. At the same time, part of the organic carbon in the sodium aluminate solution is also oxidized by wet oxidation, and the color of the sodium aluminate solution noticeably fades.

  11. Nano-textured copper oxide nanofibers for efficient air cooling

    NASA Astrophysics Data System (ADS)

    An, Seongpil; Jo, Hong Seok; Al-Deyab, Salem S.; Yarin, Alexander L.; Yoon, Sam S.

    2016-02-01

    Ever decreasing of microelectronics devices is challenged by overheating and demands an increase in heat removal rate. Herein, we fabricated highly efficient heat-removal coatings comprised of copper oxide-plated polymer nanofiber layers (thorny devil nanofibers) with high surface-to-volume ratio, which facilitate heat removal from the underlying hot surfaces. The electroplating time and voltage were optimized to form fiber layers with maximal heat removal rate. The copper oxide nanofibers with the thorny devil morphology yielded a superior cooling rate compared to the pure copper nanofibers with the smooth surface morphology. This superior cooling performance is attributed to the enhanced surface area of the thorny devil nanofibers. These nanofibers were characterized with scanning electron microscopy, X-ray diffraction, atomic force microscopy, and a thermographic camera.

  12. Effect of Gadolinium Doping on the Air Oxidation of Uranium Dioxide

    SciTech Connect

    Scheele, Randall D.; Hanson, Brady D.; Cumblidge, Stephen E.; Jenson, Evan D.; Kozelisky, Anne E.; Sell, Rachel L.; MacFarlan, Paul J.; Snow, Lanee A.

    2004-12-04

    Researchers at the Pacific Northwest National Laboratory (PNNL) investigated the effects of gadolinia concentration on the air oxidization of gadolinia-doped uranium dioxide using thermogravimetry and differential scanning calorimetry to determine if such doping could improve uranium dioxide's stability as a nuclear fuel during potential accident scenarios in a nuclear reactor or during long-term disposal. We undertook this study to determine whether the resistance of the uranium dioxide to oxidation to the orthorhombic U3O8 with its attendant crystal expansion could be prevented by addition of gadolinia. Our studies found that gadolinium has little effect on the thermal initiation of the first step of the reported two-step air oxidation of UO2; however, increasing gadolinia content does stabilize the initial tetragonal or cubic product allowing significant oxidation before the second expansive step to U3O8 begins.

  13. 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-Chen (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 percursor. 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.

  14. 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.

  15. Air oxidation of d-limonene (the citrus solvent) creates potent allergens.

    PubMed

    Karlberg, A T; Magnusson, K; Nilsson, U

    1992-05-01

    Products containing as much as 95% of d-limonene are used for, e.g., degreasing metal before industrial painting and for cleaning assemblies. Experimental studies on the sensitizing potential of limonene show diverging results. In a previous study, we found that the sensitizing potential of d-limonene increased with prolonged air exposure. The aim of this study was to make further chemical analyses, to identify compounds formed by air exposure of d-limonene and to study their allergenic potential. d-limonene was found to be a sensitizer after prolonged exposure to air according to 2 Freund's complete adjuvant test (FCAT) experiments and 1 guinea pig maximization test (GPMT) study. No significant response was obtained to d-limonene not air exposed, even if the animals were sensitized to oxidized d-limonene. 5 main oxidation products of d-limonene were identified. (R)-(-)-carvone and a mixture of cis and trans isomers of (+)-limonene oxide were found to be potent sensitizers, while no significant reactions were obtained in the animals induced with a mixture of cis and trans isomers of (-)-carveol. It can be concluded that air oxidation of d-limonene is essential for its sensitizing potential, and that potent allergens are created. PMID:1395597

  16. Mild and selective vanadium-catalyzed oxidation of benzylic, allylic, and propargylic alcohols using air.

    PubMed

    Hanson, Susan K; Wu, Ruilian; Silks, L A Pete

    2011-04-15

    Transition metal-catalyzed aerobic alcohol oxidation is an attractive method for the synthesis of carbonyl compounds, but most catalytic systems feature precious metals and require pure oxygen. The vanadium complex (HQ)(2)V(V)(O)(O(i)Pr) (2 mol %, HQ = 8-quinolinate) and NEt(3) (10 mol %) catalyze the oxidation of benzylic, allylic, and propargylic alcohols with air. The catalyst can be easily prepared under air using commercially available reagents and is effective for a wide range of primary and secondary alcohols. PMID:21434606

  17. 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.

  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. 32 CFR 806.29 - Administrative processing of Air Force FOIA requests.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Administrative processing of Air Force FOIA requests. 806.29 Section 806.29 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE ADMINISTRATION AIR FORCE FREEDOM OF INFORMATION ACT PROGRAM § 806.29 Administrative processing of Air Force FOIA requests. (a) This section...

  20. 32 CFR 806.27 - Samples of Air Force FOIA processing documents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Samples of Air Force FOIA processing documents. 806.27 Section 806.27 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE ADMINISTRATION AIR FORCE FREEDOM OF INFORMATION ACT PROGRAM § 806.27 Samples of Air Force FOIA processing documents. (a) This section...

  1. 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

  2. A solar-driven UV/Chlorine advanced oxidation process.

    PubMed

    Chan, Po Yee; Gamal El-Din, Mohamed; Bolton, James R

    2012-11-01

    An overlap of the absorption spectrum of the hypochlorite ion (OCl(-)) and the ultraviolet (UV) end of the solar emission spectrum implies that solar photons can probably initiate the UV/chlorine advanced oxidation process (AOP). The application of this solar process to water and wastewater treatment has been investigated in this study. At the bench-scale, the OCl(-) photolysis quantum yield at 303 nm (representative of the lower end of the solar UV region) and at concentrations from 0 to 4.23 mM was 0.87 ± 0.01. Also the hydroxyl radical yield factor (for an OCl(-) concentration of 1.13 mM) was 0.70 ± 0.02. Application of this process, at the bench-scale and under actual sunlight, led to methylene blue (MB) photobleaching and cyclohexanoic acid (CHA) photodegradation. For MB photobleaching, the OCl(-) concentration was the key factor causing an increase in the pseudo first-order rate constants. The MB photobleaching quantum yield was affected by the MB concentration, but not much by the OCl(-) concentration. For CHA photodegradation, an optimal OCl(-) concentration of 1.55 mM was obtained for a 0.23 mM CHA concentration, and a scavenger effect was observed when higher OCl(-) concentrations were applied. Quantum yields of 0.09 ± 0.01 and 0.89 ± 0.06 were found for CHA photodegradation and OCl(-) photolysis, respectively. In addition, based on the Air Mass 1.5 reference solar spectrum and experimental quantum yields, a theoretical calculation method was developed to estimate the initial rate for photoreactions under sunlight. The theoretical initial rates agreed well with the experimental rates for both MB photobleaching and CHA photodegradation. PMID:22939221

  3. 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.

  4. Process to manufacture effervescent tablets: air forced oven melt granulation.

    PubMed

    Yanze, F M; Duru, C; Jacob, M

    2000-12-01

    In the present study we apply melt granulation in an air forced oven, called "are forced oven melt granulation" to the single-stage manufacture of effervescent granules consisting of anhydrous citric acid (43.2%) and sodium bicarbonate (56.8%) in order to make tablets. This study established that process parameters such as concentration of PEG 6000, residence time in the air forced oven, fineness of PEG 6000, fineness of the initial effervescent mix and efficiency of two lubricants markedly influenced several granule and tablet characteristics. The granules ready to be compressed into tablets were stable for 7 days at 60% RH/18 degrees C. It is a dry, simple, rapid, effective, economical, reproducible process particularly well suited to the manufacture of effervescent granules which are easily compressed into effervescent tablets. Of all the formulations tested, only formulations B2 and E2 melt granulated for 30 minutes gave tablets which had optimum compression characteristics without processing problems during compression. PMID:11189868

  5. Ozone Generation in Air during Electron Beam Processing

    NASA Astrophysics Data System (ADS)

    Cleland, Marshall R.; Galloway, Richard A.

    Ozone, the triatomic form of oxygen, can be generated by exposing normal diatomic oxygen gas to energetic electrons, X-rays, nuclear gamma rays, short-wavelength ultraviolet radiation (UV) and electrical discharges. Ozone is toxic to all forms of life, and governmental regulations have been established to protect people from excessive exposures to this gas. The human threshold limit values (TLV) vary from 60 to 100 parts per billion (ppb) in air, depending on the agency or country involved. Much higher concentrations can be produced inside industrial electron beam (EB) facilities, so methods for ozone removal must be provided. Equations for calculating the ozone yield vs absorbed energy, the production rate vs absorbed power, and the concentration in the air of an EB facility are presented in this paper. Since the production rate and concentration are proportional to the EB power dissipated in air, they are dependent on the design and application of the irradiation facility. Examples of these calculations are given for a typical EB process to cross-link insulated electrical wire or plastic tubing. The electron energy and beam power are assumed to be 1.5 MeV and 75 kW.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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

  12. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    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.

  14. 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

  15. 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

  16. 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.

  17. Oxidation chemistry of chloric acid in NOx/SOx and air toxic metal removal from gas streams

    SciTech Connect

    Kaczur, J.J.

    1996-12-31

    Chloric acid, HClO{sub 3}, is a new oxidizer which has recently been shown to be an effective agent in the simultaneous removal of NOx and/or SOx from combustion flue gases and various chemical processes, including nitrations and metal pickling. Aqueous chloric acid readily reacts with NO and SO{sub 2} even in dilute solutions at ambient temperatures. Chlorine dioxide, ClO{sub 2}, is formed as a chemical intermediate in the solution phase oxidation reactions. The oxidation by-products of NO include NO{sub 2} and nitric acid. The ClO{sub 2} generated from the solution phase reactions also participates in gas phase oxidation reactions with NO and NO{sub 2}. The combined solution phase and fast gas phase reaction chemistries provide the means for creating a new type of high performance NOx/SOx removal process. Wet scrubber based pilot plant tests have demonstrated up to 99% removal of NO. Additional recent research work has shown that chloric acid is an effective reagent for the removal of air toxic metals, such as elemental mercury, which are present in the waste gas output streams from incinerators, hydrogen from mercury cell chlor-alkali plants, and flue gases of coal-fired power plants. Work in this area is being conducted by Argonne National Laboratories and Olin. This paper discusses the oxidation chemistry of chloric acid and its unique solution and gas phase reactions with NO, SO{sub 2}, and air toxics in wet scrubber type process equipment. 32 refs., 16 figs., 5 tabs.

  18. ADVANCED OXIDATION PROCESSES (AOP'S FOR THE TREATMENT OF CCL CHEMICALS

    EPA Science Inventory

    Research on treatment of Contaminant Candidate List (CCL) chemicals is being conducted. Specific groups of contaminants on the CCL will be evaluated using numerous advanced oxidation processes (AOPs). Initially, these CCL contaminants will be evaluated in groups based on chemical...

  19. Isothermal and cyclic oxidation of an air plasma-sprayed thermal barrier coating system

    SciTech Connect

    Haynes, J.A.; Ferber, M.K.; Porter, W.D.; Rigney, E.D.

    1996-08-01

    Thermogravimetric methods for evaluating bond coat oxidation in plasma-sprayed thermal barrier coating (TBC) systems were assessed by high-temperature testing of TBC systems with air plasma-sprayed (APS) Ni-22Cr-10Al-1Y bond coatings and yttria-stabilized zirconia top coatings. High-mass thermogravimetric analysis (at 1150{sup degrees}C) was used to measure bond coat oxidation kinetics. Furnace cycling was used to evaluate APS TBC durability. This paper describes the experimental methods and relative oxidation kinetics of the various specimen types. Characterization of the APS TBCs and their reaction products is discussed.

  20. 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

  1. 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.

  2. Process for the reduction of nitrogen oxides in an effluent

    SciTech Connect

    Epperly, W.R.; Sullivan, J.C.; Sprague, B.N.

    1989-09-05

    This patent describes a process for the reduction of the concentration of nitrogen oxides in the effluent from the combustion of a carbonaceous fuel. The process comprises introducing a heterocyclic hydrocarbon selected from the group consisting of piperazine, piperidine, pyrazine, pyrazole, imidazole, oxazolidone, pyrrole and pyrrolidine into the effluent having an effluent temperature of greater than about 1200{sup 0}F. under conditions effective to reduce the concentration of nitrogen oxides in the effluent.

  3. 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

  4. The 17O Excess of Stratospheric Nitrous Oxide in Mid-latitude Air

    NASA Astrophysics Data System (ADS)

    Ridley, A.; Kaiser, J.; Laube, J. C.

    2015-12-01

    Tropospheric nitrous oxide (N2O) has a 17O excess of (0.9±0.1) ‰ relative to Vienna Standard Mean Ocean Water (VSMOW). The origin of this 17O excess is under debate: tropospheric and stratospheric in-situ sources as well as isotope fractionation and isotope exchange during biological N2O production are all considered to make a contribution, as might the stratospheric photolysis sink. To constrain the relative contributions of the different processes and to improve our understanding of the underlying atmospheric chemical and microbial processes, more measurements are required. We have measured the 17O excess of stratospheric samples from mid-latitudes, from altitudes between 8 and 26 km. N2O was extracted cryogenically, separated from CO2 and CHF3 by a PoraPlotQ pre-column and then thermally decomposed in a gold furnace at 900 ºC. The precision for the 17O excess of a single 5 nmol N2O aliquot was ±0.3 ‰. This dataset significantly enhances the limited range of oxygen triple isotope measurements in mostly lower stratospheric samples reported by Cliff et al. (1999). The average 17O excess of the stratospheric samples analysed was (-0.19 ±0.46) ‰ relative to tropospheric N2O. Since the 17O excess of the first measurements of stratospheric air is not significantly different to that in tropospheric air, this data suggests that the 17O excess is not of stratospheric origin. This confirms the idea that the origin of the 17O excess is not due to either stratospheric photolysis or reaction with electronically excited oxygen atoms. It suggests that the origin of the 17O excess may therefore be related to tropospheric in situ sources, e.g. NH2+NO2 as proposed by Röckmann et al., 2001, or to microbial nitrogen conversion reactions as suggested by Kaiser and Röckmann, 2005.

  5. Release of air toxics during coating operations -- Understanding the process

    SciTech Connect

    Brush, P.A.; Fultz, B.S.

    1997-12-31

    Air toxics emissions, specifically volatile organic compounds (VOC), occur during the mixing, application, and drying of coatings. However, the means by which these emissions are quantified are generally a gross exaggeration. Many times this over-estimation results in the placement of permit emission limits on facilities that restrict operations unnecessarily. This paper will present and discuss the coating application process giving special attention to the points in the process and time periods over which VOCs may be released to the atmosphere. Finally, the highly conservative nature of emission estimation techniques and the methods by which permit limits are developed will be discussed and an alternative approach suggested that more closely represents VOC releases that occur during coating operations; thereby, allowing facilities to realize their operational potential without compromising the potential health impacts to offsite receptors.

  6. 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...

  7. 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...

  8. PHOTOCHEMICAL OXIDANT AIR POLLUTION EFFECTS ON A MIXED CONIFER FOREST ECOSYSTEM

    EPA Science Inventory

    EPA contract 68-03-2442 provided support for three years of the studies to determine the chronic effects of photochemical oxidant air pollutants on a western mixed conifer forest ecosystem. This report deals with the year 1976-77 and is the final publication on EPA contract 68-03...

  9. 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...

  10. 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...

  11. Spectroscopic Studies On Powdered CeNi5 Oxidized In Air

    SciTech Connect

    Coldea, M.; Pacurariu, R.; Pascut, L. G.; Rednic, V.; Neumann, M.

    2007-04-23

    The synthesis, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy. X-ray diffraction (XRD) and transmission electron microscopy (TEM) of Ni isolated single domain particles, obtained from powdered CeNi5 oxidized in air at different temperatures up to 800 deg. C, are reported.

  12. LEAF PHOTOSYNTHETIC AND WATER RELATIONS RESPONSES FOR "VALENCIA" ORANGE TREES EXPOSED TO OXIDANT AIR POLLUTION

    EPA Science Inventory

    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 exposed to ambient oxidant air pollution. xposures were continuous for four years to three le...

  13. OXIDANT AIR POLLUTANT EFFECTS ON A WESTERN CONIFEROUS FOREST ECOSYSTEM: TASK A, PLANNING CONFERENCE

    EPA Science Inventory

    This is a report on a planning conference to develop a protocol for a study on the impact of oxidant air pollution from an urban area on a forest ecosystem and recreational area. The conference was held July 21-23, 1971 at the Arrowhead Conference Center in California to discuss ...

  14. THE EFFECTS OF OXIDANT AIR POLLUTANTS ON SOYBEANS, SNAP BEANS AND POTATOES

    EPA Science Inventory

    During the past 5 years the impact of photochemical oxidants on soybeans and snap beans in Maryland and on potatoes in Virginia and Delaware was assessed with open-top chambers. The mean yields of four selected soybean varieties grown in open-top chambers with carbon-filtered air...

  15. 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...

  16. Surface activation of air oxidation of hydrazine on kaolinite. 2. Consideration of oxidizing/reducing entities in relationship to other compositional, structural, and energetic factors

    NASA Technical Reports Server (NTRS)

    Coyne, L. M.; Summers, D. P.

    1991-01-01

    The rates (previously reported) for the air oxidation of hydrazine on kaolinite and substituent oxides of kaolinite showed a complex dependence on the relative amounts of several structural oxidizing/reducing entities within the reaction-promoting solids. The rates indicated an important role of the clay but no dominant role of any one of the oxidizing/reducing entities. In this paper we review (a) the reaction-promoting activity of these centers as studied in other systems, (b) various spectroscopic results showing interaction between these entities in clays, and (c) reported spectroscopic studies of the complexation between hydrazine and aluminosilicate surfaces as a whole, in an effort to propose a mechanism for the reaction. Whereas some uncertainties remain, the present synthesis concludes that a mechanism operating through single electron/hole transfers and hydrogen atom transfers by discrete centers is adequate to explain the observed rate behaviors including the observed second order dependence of the oxidation rate on catalyst amount. The effects of these operations on the catalyst can result in no alteration of, or complete or partial electronic relaxation of its contingent of trapped separated charge pairs. The degree to which surface complexation as a whole, intercalation, or luminescent processes may also be associated with the reaction cannot be adequately assessed with the information in hand.

  17. Effects of air oxidation on the dissolution rate of LWR spent fuel

    SciTech Connect

    Gray, W.J.; Thomas, L.E.; Einziger, R.E.

    1993-12-31

    Dissolution rates for air-oxidized spent fuel were measured in flowthrough tests where U concentrations were kept well below the solubility limit. Results from two types of specimens, separated grains and coarse particles, both in oxidized (U{sub 4}O{sub 9+x}) and unoxidized (UO{sub 2}) conditions indicated only minor effects of oxidation on the surface-area-normalized rates. Similar results were obtained for unirradiated specimens in three different oxidation states (UO{sub 2}, U{sub 3}O{sub 7}, and U{sub 3}O{sub 8}). These observations have important practical implications for disposal of spent fuel in a geologic repository as well as implications regarding the oxidative dissolution mechanism of UO{sub 2} fuel.

  18. 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, S.; Williams, R. W.; Mukerjee, S.; Neas, L. M.

    2013-12-01

    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 a large mobile monitoring dataset collected on a roadway network in central North Carolina to explore common data processing strategies including time-alignment, short-term emissions event detection, background estimation, and averaging techniques. One-second time resolution measurements of ultrafine particles ≤ 100 nm in diameter (UFPs), black carbon (BC), particulate matter (PM), carbon monoxide (CO), carbon dioxide (CO2), and nitrogen dioxide (NO2) were collected on twelve unique driving routes that were repeatedly sampled. Analyses demonstrate that the multiple emissions event detection strategies reported produce generally similar results and that utilizing a median (as opposed to a mean) as a summary statistic may be sufficient to avoid bias in near-source spatial trends. Background levels of the pollutants are shown to vary with time, and the estimated contributions of the background to the mean pollutant concentrations were: BC (6%), PM2.5-10 (12%), UFPs (19%), CO (38%), PM10 (45%), NO2 (51%), PM2.5 (56%), and CO2 (86%). Lastly, while temporal smoothing (e.g., 5 s averages) results in weak pair-wise correlation and the blurring of spatial trends, spatial averaging (e.g., 10 m) is demonstrated to increase correlation and refine spatial trends.

  19. OXIDANT AIR POLLUTION IN REMOTE FORESTED AREAS OF SOUTHWESTERN VIRGINIA. OXIDANT EFFECT ON EASTERN WHITE PINE

    EPA Science Inventory

    Total oxidants and associated oxidant injury to white pine were determined at three rural sites in Virginia: (1) Salt Pond Mountain, Giles County; (2) Rocky Knob Mountain, Floyd County; and, (3) Shenandoah Valley, Rockingham County, at 945 m, 945 m, and 426 m elevation, respectiv...

  20. 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.

  1. 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.

  2. Wet air oxidation for the treatment of industrial wastes. Chemical aspects, reactor design and industrial applications in Europe

    SciTech Connect

    Debellefontaine, H.; Foussard, J.N.

    2000-07-01

    Aqueous wastes containing organic pollutants can be efficiently treated by wet air oxidation (WAO), i.e., oxidation (or combustion) by molecular oxygen in the liquid phase, at high temperature (200--325 C) and pressure (up to 175 bar). This method is suited to the elimination of special aqueous wastes from the chemical industry as well as to the treatment of domestic sludge. It is an enclosed process, with a limited interaction with the environment, as opposed to incineration. Usually, the operating cost is lower than 95 Euro M{sup {minus}3} and the preferred COD load ranges from 10 to 80 kg m{sup {minus}3}. Only a handful of industrial reactors are in operation world-wide, mainly because of the high capital investment they require. This paper reviews the major results obtained with the WAO process and assess its field of possible application to industrial wastes. In addition, as only a very few studies have been devoted to the scientific design of such reactors (bubble columns), what needs to be known for this scientific design is discussed. At present, a computer program aimed at determining the performance of a wet air oxidation reactor depending on the various operating parameters has been implemented at the laboratory. Some typical results are presented, pointing out the most important parameters and the specific behavior of these units.

  3. 32 CFR 806.29 - Administrative processing of Air Force FOIA requests.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 6 2014-07-01 2014-07-01 false Administrative processing of Air Force FOIA... FORCE ADMINISTRATION AIR FORCE FREEDOM OF INFORMATION ACT PROGRAM § 806.29 Administrative processing of Air Force FOIA requests. (a) This section is a checklist format of processing steps and...

  4. 32 CFR 806.29 - Administrative processing of Air Force FOIA requests.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Administrative processing of Air Force FOIA... FORCE ADMINISTRATION AIR FORCE FREEDOM OF INFORMATION ACT PROGRAM § 806.29 Administrative processing of Air Force FOIA requests. (a) This section is a checklist format of processing steps and...

  5. 32 CFR 806.29 - Administrative processing of Air Force FOIA requests.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Administrative processing of Air Force FOIA... FORCE ADMINISTRATION AIR FORCE FREEDOM OF INFORMATION ACT PROGRAM § 806.29 Administrative processing of Air Force FOIA requests. (a) This section is a checklist format of processing steps and...

  6. 32 CFR 806.29 - Administrative processing of Air Force FOIA requests.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 6 2013-07-01 2013-07-01 false Administrative processing of Air Force FOIA... FORCE ADMINISTRATION AIR FORCE FREEDOM OF INFORMATION ACT PROGRAM § 806.29 Administrative processing of Air Force FOIA requests. (a) This section is a checklist format of processing steps and...

  7. CAVITATIONAL HYDROTHERMAL OXIDATION: A NEW REMEDIATION PROCESS

    EPA Science Inventory

    This research will explore the emerging science of sonochemistry and its technological applications for organic waste remediation, particularly for water and soil purification. Ultrasound can induce unusual high-energy chemistry through the process of acoustic cavitation: the for...

  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. 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.

  10. 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.

  11. Treatment of linear alkylbenzene sulfonate (LAS) wastewater by internal electrolysis--biological contact oxidation process.

    PubMed

    Cao, X Z; Li, Y M

    2011-01-01

    Surfactant wastewater is usually difficult to treat due to its toxicity and poor biodegradability. A separate physico-chemical or biochemical treatment method achieves a satisfactory effect with difficulty. In this study, treatment of the wastewater collected from a daily chemical plant by the combination processes of Fe/C internal electrolysis and biological contact oxidation was investigated. For the internal electrolysis process, the optimal conditions were: pH = 4-5, Fe/C = (10-15):1, air-water ratio = (10-20):1 and hydraulic retention time (HRT)= 2 h. For the biological contact oxidation process, the optimal conditions were: HRT = 12 h, DO = 4.0-5.0 mg/L. Treated by the above combined processes, the effluent could meet the I-grade criteria specified in Integrated Wastewater Discharge Standard of China (GB 8978-1996). The results provide valuable information for full-scale linear alkylbenzene sulfonate wastewater treatment. PMID:22053469

  12. Laser Processing of Metal Oxides for Plasmonic Applications

    NASA Astrophysics Data System (ADS)

    Kim, Heungsoo; Breckenfeld, Eric; Charipar, Nicholas; Pique, Alberto

    Noble metals such as Au and Ag have been used traditionally for plasmonic devices. However, conventional metals are not suitable for near infrared (IR) plasmonic applications due to their relatively large optical losses at these wavelengths. Metal oxides, on the other hand, have been considered for low loss metallic components in the near IR because they can provide a tunable carrier density by doping. The zero-cross-over permittivity values of these metal oxides, for example, can easily be tuned from 1.0 µm to 3 µm by adjusting doping levels. Optical losses in devices made from these metal oxide materials are generally found to be much lower than those obtained with conventional metals. We have investigated various laser processing techniques for synthesizing several types of metal oxides. First, pulsed laser deposition was used to grow metal oxide thin films such as, Al-doped ZnO, Sn-doped In2O3 and VO2. Second, a laser sintering technique was used to improve the properties of solution-processed VO2 coatings. Third, a laser printing technique was used to produce metal oxide films. We will present details on the use of laser processing techniques for synthesizing these metal oxides along with their electrical, optical, and structural properties. This work was funded by the Office of Naval Research (ONR) through the Naval Research Laboratory Basic Research Program.

  13. 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.

  14. 32 CFR 806.27 - Samples of Air Force FOIA processing documents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Samples of Air Force FOIA processing documents. 806.27 Section 806.27 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE ADMINISTRATION AIR FORCE FREEDOM OF INFORMATION ACT PROGRAM § 806.27 Samples of Air Force FOIA...

  15. 32 CFR 806.27 - Samples of Air Force FOIA processing documents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 6 2013-07-01 2013-07-01 false Samples of Air Force FOIA processing documents. 806.27 Section 806.27 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE ADMINISTRATION AIR FORCE FREEDOM OF INFORMATION ACT PROGRAM § 806.27 Samples of Air Force FOIA...

  16. 32 CFR 806.27 - Samples of Air Force FOIA processing documents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Samples of Air Force FOIA processing documents. 806.27 Section 806.27 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE ADMINISTRATION AIR FORCE FREEDOM OF INFORMATION ACT PROGRAM § 806.27 Samples of Air Force FOIA...

  17. 32 CFR 806.27 - Samples of Air Force FOIA processing documents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 6 2014-07-01 2014-07-01 false Samples of Air Force FOIA processing documents. 806.27 Section 806.27 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE ADMINISTRATION AIR FORCE FREEDOM OF INFORMATION ACT PROGRAM § 806.27 Samples of Air Force FOIA...

  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. 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.

  20. Oxidation kinetics of some nickel-based superalloy foils and electronic resistance of the oxide scale formed in air. Part 1

    SciTech Connect

    England, D.M.; Virkar, A.V.

    1999-09-01

    Haynes 230, Inconel 625, Inconel 718, and Hastelloy X foil specimens were oxidized in air for several thousand hours in the temperature range of 800--1,100 C. The oxidation kinetics of alloys studied obeyed the parabolic rate law. Haynes 230 exhibited the slowest oxidation kinetics of the alloys studied. X-ray diffraction, scanning electron microscopy, and electron probe microanalysis (EPMA) were the principal characterization tools employed. Chromium oxide, Cr{sub 2}O{sub 3}, was the predominant oxide phase in the oxide scale of all alloys studied. Manganese chromate was also detected in the oxide scales of Haynes 230, Hastelloy X, and Inconel 625. EPMA showed that the concentration of Mn in the oxide scale was much higher than in the alloy, indicating selective oxidation of Mn. The electronic resistance of the oxide scale was measured in air at temperatures up to 800 C on samples oxidized in air for up to several thousand hours. The oxide scale on Haynes 230 exhibited the lowest area-specific resistance, consistent with its slower oxidation kinetics.

  1. 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

    ... 40 Protection of Environment 2 2010-07-01 2010-07-01 false National primary and secondary ambient... PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.11 National primary and secondary ambient air... national primary annual ambient air quality standard for oxides of nitrogen is 53 parts per billion...

  2. 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... SECONDARY AMBIENT AIR QUALITY STANDARDS Pt. 50, App. S Appendix S to Part 50—Interpretation of the Primary... be submitted to EPA's Air Quality System (AQS), or otherwise available to EPA, meeting...

  3. Costs of the electrochemical oxidation of wastewaters: a comparison with ozonation and Fenton oxidation processes.

    PubMed

    Cañizares, Pablo; Paz, Rubén; Sáez, Cristina; Rodrigo, Manuel A

    2009-01-01

    In the work described here the technical and economic feasibilities of three Advanced Oxidation Processes (AOPs) have been studied: Conductive-Diamond Electrochemical Oxidation (CDEO), Ozonation and Fenton oxidation. The comparison was made by assessing the three technologies with synthetic wastewaters polluted with different types of organic compounds and also with actual wastes (from olive oil mills and from a fine-chemical manufacturing plant). All three technologies were able to treat the wastes, but very different results were obtained in terms of efficiency and mineralization. Only CDEO could achieve complete mineralization of the pollutants for all the wastes. However, the efficiencies were found to depend on the concentration of pollutant (mass transfer control of the oxidation rate). Results obtained in the oxidation with ozone (at pH 12) or by Fenton's reagent were found to depend on the nature of the pollutants, and significant concentrations of oxidation-refractory compounds were usually accumulated during the treatment. Within the discharge limits that all of the technologies can reach, the economic analysis shows that the operating cost of Fenton oxidation is lower than either CDEO or ozonation, although CD\\EO can compete satisfactorily with the Fenton process in the treatment of several kinds of wastes. Likewise, the investment cost for the ozonation process seems to be higher than either CDEO or Fenton oxidation, regardless of the pollutant treated. PMID:18082930

  4. [Effect of flue gas conditions on NO oxidation process by DC corona radical shower].

    PubMed

    Wu, Zu-liang; Gao, Xiang; Li, Ming-bo; Zhang, Yuan-shang; Wu, Zu-cheng; Luo, Zhong-yang; Ni, Ming-jiang; Cen, Ke-fa

    2005-05-01

    Using an air-H2O DC corona radical shower system, the influences of reside time of flue gas in the reactor, velocity of flue gas and NO concentration on NO oxidation process were studied. The results show that the increasing velocity of flue gas can restrain corona development and the increasing NO concentration can make discharge more easy. The reside time of flue gas in the reactor has less effect on the NO oxidation. The NO oxidation rate increased only from 54.5% to 57.6% at 2 W input power when the reside time of flue gas in the reactor increased from 8.5 s to 34.2 s. However, the velocity of flue gas has important effect on the NO oxidation. At 1.7 W x h/m3 energy density, when the velocity of flue gas increased from 1.4 cm/s to 6.3 cm/s, the NO oxidation rate dropped from 60.0% to 38.6% and the energy yield also falled from 20.8 g/(kW x h) to 13.3 g/(kW x h). Under the certain flux of humid air, NO initial concentration has a best value, which was about 100 x 10(-6) in this experiment. PMID:16124460

  5. 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.

  6. 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

  7. Mechanism of the Initial Oxidation of Hydrogen andHalogen Terminated Ge(111) Surfaces in Air

    SciTech Connect

    Sun, Shiyu; Sun, Yun; Liu, Zhi; Lee, Dong-Ick; Pianetta, Piero; /SLAC, SSRL

    2006-08-23

    The initial stage of the oxidation of Ge(111) surfaces etched by HF, HCl and HBr solutions is systematically studied using synchrotron radiation photoelectron spectroscopy (SR-PES). We perform controlled experiments to differentiate the effects of different oxidation factors. SR-PES results show that both moisture and oxygen contribute to the oxidation of the surfaces; however, they play different roles in the oxidation process. Moisture effectively replaces the hydrogen and halogen termination layers with hydroxyl (OH), but hardly oxidizes the surfaces further. On the other hand, dry oxygen does not replace the termination layers, but breaks the Ge-Ge back bonds and oxidizes the substrates with the aid of moisture. In addition, room light enhances the oxidation rate significantly.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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. PMID:24804662

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Effects of different surfaces on the transport and deposition of ruthenium oxides in high temperature air

    NASA Astrophysics Data System (ADS)

    Vér, N.; Matus, L.; Pintér, A.; Osán, J.; Hózer, Z.

    2012-01-01

    In order to understand the behaviour of ruthenium oxides in the reactor coolant system during an air ingress accident, new tests were performed in the frame of the RUSET (RUthenium Separate Effect Test) experimental program. These aimed to ascertain the effects of different surfaces (quartz, stainless steel (SS), zirconium alloy, alumina, oxidised metal, and surfaces with Mo or Cs deposits) on the transport and decomposition of ruthenium oxides in air stream along the temperature gradient zone (1100-100 °C). The results demonstrated that the heterogeneous phase decomposition of RuO 3 and RuO 4 to RuO 2 is catalysed more efficiently by the quartz surface than by the SS or alumina surfaces. The presence of MoO 3 layers decreased the RuO x precipitation extent on all investigated surfaces. The trapping effect of Cs deposit on Ru in the temperature gradient zone was proved in the case of the SS surface. On the contrary, presence of Cs precipitate on alumina and especially on quartz surfaces was found to decrease their catalytic effect on the decomposition of ruthenium oxides, and thus increased the RuO 4 concentration in the outlet air. Similarly to the effect observed for Cs deposition, the presence of other fission products in the evaporation area (at 1100 °C) decreased the partial pressure of RuO 4 in the outlet air at the SS surface and increased it at quartz and alumina surfaces. When zirconium (E110) cladding material was placed in the temperature gradient zone, no Ru transmittance occurred until the high temperature end of the zirconium tube was completely oxidised. After the intense oxidation of E110, Ru release occurred only in the presence of other fission product species. Pre-oxidation of SS surfaces in steam had no significant effect on the Ru passage.

  1. [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

  2. 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.

  3. 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

  4. 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...

  5. Development Studies for a Novel Wet Oxidation Process

    SciTech Connect

    Delphi Research

    1999-09-30

    DETOX is a catalyzed wet oxidation process that 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 III effort for this project is fabrication, assembly, and installation of the DETOX demonstration unit, preparation of documentation and training to meet site requirements for operation, followed by system run-in and shakedown testing of the unit prior to demonstration testing. The Title III design was completed and the unit was fabricated according to standards set forth by OSHA, EPA, the American Petroleum Institute (i.e., chemical and petroleum industry standards), and the ASME B-313 Piping Code requirements as agreed to in preliminary design meetings with primary stakeholders. The unit was assembled in three modules and two trailers and then shipped to the TNX facility at the Savannah River Site in September and october of 1996. On-going site integration tasks were address while delays in installation arose due to funding sources and costs. In March of 1997, Delphi was authorized to proceed with the installation of the unit, making electrical and mechanical connections necessary to operate the unit. All installation tasks were completed in August of 1997. Results of an Operational Readiness Review conducted in August 1997 verified that Delphi's procedures and documentation met the necessary requirements to operate the unit at SRS. Completion of the final checklist of WSRC requirements was then addressed including the Owner's Independent Inspection Report, verifying all components of the unit met B-31.3 standards. Final hydraulic and pneumatic tests were completed in November to satisfy the B-31

  6. 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.

  7. Mechanical and tribological properties of oxide layers obtained on titanium in the thermal oxidation process

    NASA Astrophysics Data System (ADS)

    Aniołek, K.; Kupka, M.; Barylski, A.; Dercz, G.

    2015-12-01

    The paper presents the results of tests concerning a modification to the surface of titanium Grade 2 in the thermal oxidation process. It describes the oxidation kinetics of the tested material in the temperature range of 600-800 °C, with a duration from 20 min to 72 h. The greatest increase in mass was found in specimens oxidised at a temperature of 800 °C. The morphology of the obtained oxide layers was determined. The particles of oxides formed were noticeably larger after oxidation at a temperature of 600 °C. Raising temperature resulted in the formation of fine compact particles in the oxide layer. A phase analysis of oxidation products showed that TiO2 in the crystallographic form of rutile and Ti3O are the prevalent types of oxide at a temperature of 600 and 700 °C. On the other hand, only rutile formed at a temperature of 800 °C. Tribological tests showed that the presence of an oxide layer on the surface of titanium significantly improved resistance to abrasive wear. It was found that volumetric wear had decreased by 48% for a specimen oxidised at a temperature of 600 °C and by more than 60% for a specimen subjected to isothermal soaking at a temperature of 700 °C.

  8. 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.

  9. Reactive nanophase oxide additions to melt-processed high-{Tc} superconductors

    SciTech Connect

    Goretta, K.C.; Brandel, B.P.; Lanagan, M.T.; Hu, J.; Miller, D.J.; Sengupta, S.; Parker, J.C.; Ali, M.N.; Chen, Nan

    1994-10-01

    Nanophase TiO{sub 2} and Al{sub 2}O{sub 3} powders were synthesized by a vapor-phase process and mechanically mixed with stoichiometric YBa{sub 2}Cu{sub 3}O{sub x} and TlBa{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} powders in 20 mole % concentrations. Pellets produced from powders with and without nanophase oxides were heated in air or O{sub 2} above the peritectic melt temperature and slow-cooled. At 4.2 K, the intragranular critical current density (J{sub c}) increased dramatically with the oxide additions. At 35--50 K, effects of the oxide additions were positive, but less pronounced. At 77 K, the additions decreased J{sub c}, probably because of inducing a depresion of the transition temperature.

  10. Reactive nanophase oxide additions to melt-processed high-T(sub c) superconductors

    NASA Astrophysics Data System (ADS)

    Goretta, K. C.; Brandel, B. P.; Lanagan, M. T.; Hu, J.; Miller, D. J.; Sengupta, S.; Parker, J. C.; Ali, M. N.; Chen, Nan

    1994-10-01

    Nanophase TiO2 and Al2O3 powders were synthesized by a vapor-phase process and mechanically mixed with stoichiometric YBa2Cu3O(x) and TlBa2Ca2Cu3O(x) powders in 20 mole % concentrations. Pellets produced from powders with and without nanophase oxides were heated in air or O2 above the peritectic melt temperature and slow-cooled. At 4.2 K, the intragranular critical current density J(sub c)) increased dramatically with the oxide additions. At 35-50 K, effects of the oxide additions were positive, but less pronounced. At 77 K, the additions decreased J(sub c), probably because of inducing a depression of the transition temperature.

  11. Second-harmonic generation in metal oxide/ormosils nanocomposites derived from sol-gel processing

    NASA Astrophysics Data System (ADS)

    Cheng, Chih-Hsing; Xu, Yuhuan; Mackenzie, John D.; Chee, Joseph K.; Liu, Jia-ming

    1992-12-01

    Nanocomposites of Ormosis containing metal oxides, such as niobates, titanates and zirconates, were prepared by sol-gel processing. The materials were hydrolyzed partially and were dried in air atmosphere for appropriate periods. Afterwards, the materials were heat- treated between 200 degree(s) and 450 degree(s)C for 2 days in pure oxygen. The final bulk samples are transparent in infrared and visible ranges. X-ray diffraction patterns showed that these samples did not have any crystalline phases after heating up to 200 degree(s)C. Using a Nd:YAG laser of 1.064 micrometers wavelength, second harmonic generation, of green light (0.532 micrometers ), was observed in these metal oxides/Ormosils nanocomposites. The refractive index and other optical properties of the metal oxides/Ormosils were also measured. The microstructures of these samples were examined by transmission electron microscopy.

  12. 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.

  13. 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.

  14. 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.

  15. Simulation of Triple Oxidation Ditch Wastewater Treatment Process

    NASA Astrophysics Data System (ADS)

    Yang, Yue; Zhang, Jinsong; Liu, Lixiang; Hu, Yongfeng; Xu, Ziming

    2010-11-01

    This paper presented the modeling mechanism and method of a sewage treatment system. A triple oxidation ditch process of a WWTP was simulated based on activated sludge model ASM2D with GPS-X software. In order to identify the adequate model structure to be implemented into the GPS-X environment, the oxidation ditch was divided into several completely stirred tank reactors depended on the distribution of aeration devices and dissolved oxygen concentration. The removal efficiency of COD, ammonia nitrogen, total nitrogen, total phosphorus and SS were simulated by GPS-X software with influent quality data of this WWTP from June to August 2009, to investigate the differences between the simulated results and the actual results. The results showed that, the simulated values could well reflect the actual condition of the triple oxidation ditch process. Mathematical modeling method was appropriate in effluent quality predicting and process optimizing.

  16. In situ characterization of Zircaloy-4 oxidation at 500 °C in dry air

    NASA Astrophysics Data System (ADS)

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

    2001-10-01

    The in situ oxidation of Zircaloy-4 at 500 °C in dry air was investigated by thermogravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS). The coating of the alloy by a platinum film as electrode material was observed as not to modify the oxidation kinetic properties. After an initial cubic rate law, a transition to a quasi-linear curve occurs. The independence of the oxidation behavior to the Pt coupling is compatible with oxygen diffusion as the rate-determining step. During the pre-transition step, the rest potential of the cell Pt/oxide/Zy-4, the color of the oxide and the modulus of the single EIS signature indicate the high non-stoichiometry of the oxide. The kinetic transition was proposed to be correlated to the degradation of the film into a partially porous layer. This alteration of the oxide is associated to the appearance of a 1.2 V constant rest potential and the modification of the impedance diagrams in two high modulus contributions. The Cole-Cole representation has been used to demonstrate that the time variation of impedance spectra is related to the oxide growth. An equivalent circuit including two RC loops in series, whose capacitances are frequency dispersed, was proposed to be related to the film structure. Fitted data show that the thickness of the assumed protective layer of the film, close to the metal-oxide interface, is time independent in agreement with a constant oxidation rate. Finally, electrical properties of this inner layer were found to be quite different in pre- and post-transition stage.

  17. 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.

  18. 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).

  19. Developing Oxidized Nitrogen Atmospheric Deposition Source Attribution from CMAQ for Air-Water Trading for Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Dennis, R. L.; Napelenok, S. L.; Linker, L. C.; Dudek, M.

    2012-12-01

    Estuaries are adversely impacted by excess reactive nitrogen, Nr, from many point and nonpoint sources, including atmospheric deposition to the watershed and the estuary itself as a nonpoint source. For effective mitigation, trading among sources of Nr is being considered. The Chesapeake Bay Program is working to bring air into its trading scheme, which requires some special air computations. Airsheds are much larger than watersheds; thus, wide-spread or national emissions controls are put in place to achieve major reductions in atmospheric Nr deposition. The tributary nitrogen load reductions allocated to the states to meet the TMDL target for Chesapeake Bay are large and not easy to attain via controls on water point and nonpoint sources. It would help the TMDL process to take advantage of air emissions reductions that would occur with State Implementation Plans that go beyond the national air rules put in place to help meet national ambient air quality standards. There are still incremental benefits from these local or state-level controls on atmospheric emissions. The additional air deposition reductions could then be used to offset water quality controls (air-water trading). What is needed is a source to receptor transfer function that connects air emissions from a state to deposition to a tributary. There is a special source attribution version of the Community Multiscale Air Quality model, CMAQ, (termed DDM-3D) that can estimate the fraction of deposition contributed by labeled emissions (labeled by source or region) to the total deposition across space. We use the CMAQ DDM-3D to estimate simplified state-level delta-emissions to delta-atmospheric-deposition transfer coefficients for each major emission source sector within a state, since local air regulations are promulgated at the state level. The CMAQ 4.7.1 calculations are performed at a 12 km grid size over the airshed domain covering Chesapeake Bay for 2020 CAIR emissions. For results, we first present

  20. 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.

  1. 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

    2016-04-01

    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.

  2. Air oxidation behavior of fuel for the High Temperature Engineering Test Reactor (HTTR)

    NASA Astrophysics Data System (ADS)

    Kikuchi, Hironobu; Hayashi, Kimio; Fukuda, Kousaku

    1992-08-01

    The oxidation behavior of the HTTR fuel was studied with respect to the scenario of an air ingress accident which had been assessed in the HTTR safety analysis. The coated fuel particles were heated under a sufficient air flow in the temperature range of 900-1400 C for maximum duration of 600 h (at 1300 C). Failure fractions of the SiC coating layer after the heat treatments remained within the fraction at the fuel production. And the failure behavior of the SiC layer did not depend on such heating conditions as the temperature and the duration in the present experiment. It was confirmed by scanning electron microscopy (SEM), X-ray diffraction, and laser Raman spectroscopy that a thin oxide film was formed on the SiC layer by the heat treatments.

  3. 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.

  4. 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

  5. 40 CFR Appendix T to Part 50 - Interpretation of the Primary National Ambient Air Quality Standards for Oxides of Sulfur (Sulfur...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Ambient Air Quality Standards for Oxides of Sulfur (Sulfur Dioxide) T Appendix T to Part 50 Protection of... Ambient Air Quality Standards for Oxides of Sulfur (Sulfur Dioxide) 1. General (a) This appendix explains... ambient air quality standards for Oxides of Sulfur as measured by Sulfur Dioxide (“SO2 NAAQS”)...

  6. 40 CFR Appendix T to Part 50 - Interpretation of the Primary National Ambient Air Quality Standards for Oxides of Sulfur (Sulfur...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Ambient Air Quality Standards for Oxides of Sulfur (Sulfur Dioxide) T Appendix T to Part 50 Protection of... Ambient Air Quality Standards for Oxides of Sulfur (Sulfur Dioxide) 1. General (a) This appendix explains... ambient air quality standards for Oxides of Sulfur as measured by Sulfur Dioxide (“SO2 NAAQS”)...

  7. 40 CFR Appendix T to Part 50 - Interpretation of the Primary National Ambient Air Quality Standards for Oxides of Sulfur (Sulfur...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Ambient Air Quality Standards for Oxides of Sulfur (Sulfur Dioxide) T Appendix T to Part 50 Protection of... Ambient Air Quality Standards for Oxides of Sulfur (Sulfur Dioxide) 1. General (a) This appendix explains... ambient air quality standards for Oxides of Sulfur as measured by Sulfur Dioxide (“SO2 NAAQS”)...

  8. 40 CFR Appendix T to Part 50 - Interpretation of the Primary National Ambient Air Quality Standards for Oxides of Sulfur (Sulfur...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Ambient Air Quality Standards for Oxides of Sulfur (Sulfur Dioxide) T Appendix T to Part 50 Protection of... Ambient Air Quality Standards for Oxides of Sulfur (Sulfur Dioxide) 1. General (a) This appendix explains... ambient air quality standards for Oxides of Sulfur as measured by Sulfur Dioxide (“SO2 NAAQS”)...

  9. Process Design for Preventing the Gate Oxide Thinning in the Integration of Dual Gate Oxide Transistor

    NASA Astrophysics Data System (ADS)

    Kim, Seong-Ho; Kim, Sung-Hoan; Kim, Sung-Eun; Kim, Myung-Soo; Park, Joo-Han; Kim, Eun-Soo; Kim, Jin-Tae

    2002-04-01

    In this study, a method is proposed to alleviate a gate oxide (GOX) thinning problem at the edge of shallow trench isolation (STI), when STI is adopted in the dual gate oxide process (DGOX). It is well known that the DGOX process is usually used for realizing both low and high voltage operating parts in one chip. However, it is found that severe GOX thinning occurs from 320 Å (in active area) to 79 Å (at STI top edge) and a dent profile exists at the top edge of STI, when conventional DGOX and STI processes are adopted. In order to solve these problems, a new DGOX process is used in this study. The GOX thinning is prevented mainly by a combination of a thick sidewall oxide with SiN pullback. Therefore, good subthreshold characteristics without a so-called double hump are obtained by the prevention of GOX thinning and a deep dent profile.

  10. 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.

  11. 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.

  12. 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. PMID:24812662

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Effect of processing on structural features of anodic aluminum oxides

    NASA Astrophysics Data System (ADS)

    Erdogan, Pembe; Birol, Yucel

    2012-09-01

    Morphological features of the anodic aluminum oxide (AAO) templates fabricated by electrochemical oxidation under different processing conditions were investigated. The selection of the polishing parameters does not appear to be critical as long as the aluminum substrate is polished adequately prior to the anodization process. AAO layers with a highly ordered pore distribution are obtained after anodizing in 0.6 M oxalic acid at 20 °C under 40 V for 5 minutes suggesting that the desired pore features are attained once an oxide layer develops on the surface. While the pore features are not affected much, the thickness of the AAO template increases with increasing anodization treatment time. Pore features are better and the AAO growth rate is higher at 20 °C than at 5 °C; higher under 45 V than under 40 V; higher with 0.6 M than with 0.3 M oxalic acid.

  2. Atherosclerotic process in taxi drivers occupationally exposed to air pollution and co-morbidities.

    PubMed

    Brucker, Natália; Charão, Mariele F; Moro, Angela M; Ferrari, Pedro; Bubols, Guilherme; Sauer, Elisa; Fracasso, Rafael; Durgante, Juliano; Thiesen, Flávia V; Duarte, Marta M; Gioda, Adriana; Castro, Iran; Saldiva, Paulo H; Garcia, Solange C

    2014-05-01

    Consistent evidence has indicated that the exposure to environmental air pollution increases the risk of cardiovascular disease. This study aimed to evaluate the possible effects of occupational exposure to air pollution, especially to polycyclic aromatic hydrocarbons (PAHs), and the influence of co-morbidities on the atherosclerotic process and inflammation. For that, biomarkers of exposure such as 1-hydroxypyrene urinary, oxidative damage and markers of cardiovascular risk were determined in plasma, serum and blood. In addition, inflammation models such as carotid intima-media thickness and serum inflammatory cytokines were analyzed in 58 taxi drivers with and without co-morbidity. The results demonstrated that considering only taxi drivers without co-morbidities, 15% presented carotid intima-media thickness above reference values. For the first time it has been demonstrated that urinary 1-hydroxypyrene levels were associated with carotid intima-media thickness and with serum homocysteine levels. The multiple linear regression analysis showed that several factors may contribute to the increased carotid intima-media thickness, among which age, interleukin-6, fibrinogen and exposure to PAHs stand out. In summary, our results suggest that chronic occupational exposure to atmospheric pollution could be an additional contributor to the atherogenesis process, leading to impaired vascular health. Moreover, carotid intima-media thickness, serum homocysteine levels, fibrinogen and the total cholesterol/HDL-c ratio could be suggested as preventive measures to monitor drivers' health. PMID:24637182

  3. Development and Application of a Process Analysis Method for Photochemical Oxidant Models

    NASA Astrophysics Data System (ADS)

    Tonnesen, Shawn

    1995-01-01

    The U.S. Environmental Protection Agency's ozone control strategy requires that numerical air quality models be used to simulate photochemical and physical processes effecting ozone concentrations and to predict the level of control of hydrocarbons or nitrogen oxides required to attain the ozone standard. Large uncertainties exist, however, in the application of air quality models. The failure to attain ozone standards may in part be attributed to uncertainties and errors in ozone modeling. The goal of this work has been to develop an analysis method that can be used to understand and explain model predictions, thereby reducing errors and uncertainty in air quality modeling. I have developed a process analysis method which explains model predictions by performing a mass balance on the individual photochemical reactions and other physical processes which effect trace species concentrations. This method first requires minor modifications to existing air quality models to produce output files containing the integrated rates, or mass throughputs, of each reaction and each of the other physical processes. I have written a post-processing program which reads the integrated rate files and produces a series of tables which explain the model predictions. These tables summarize the production, propagation and termination of radical species, the mass of hydrocarbons and nitrogen oxides reacted, yields of ozone and odd oxygen per hydrocarbon reacted, and complete mass balances on important species. The process analysis method is summarized below and described in a series of four published papers and one submitted manuscript which apply the method to current issues in air quality modeling. These issues include: comparisons of photochemical reaction mechanisms; a study of the contribution of carbon monoxide, methane and biogenic hydrocarbons to ozone production; an analysis of hydrocarbon incremental reactivity; and applications to photochemical grid models. The papers

  4. Patterning process and actuation in open air of micro-beam actuator based on conducting IPNs

    NASA Astrophysics Data System (ADS)

    Khaldi, Alexandre; Plesse, Cédric; Soyer, Caroline; Chevrot, Claude; Teyssié, Dominique; Vidal, Frédéric; Cattan, Eric

    2012-04-01

    We report on new method to obtain micrometric electroactive polymer actuators operating in air. High speed conducting Interpenetrating Polymer Network (IPN) microactuators are synthesized and fully characterized. The IPN architecture used in this work allows solving the interface and adhesion problems, which have been reported in the design of classical conducting polymer-based actuators. We demonstrated that it is possible to reduce the thickness of these actuators by a specific synthetic pathway. IPN host matrixes based on polyethylene oxide / polytetrahydrofurane have been shaped by hot pressing. Then, the resulting thin host matrixes (below 10 μm) are compatible with the microfabrication technologies. After interpenetration of poly(3,4-ethylenedioxythiophene) (PEDOT), these electroactive materials are micro-sized using dry etching process. Frequency responses and displacement have been characterized by scanning electronic microscopy. These conducting IPN microactuators can be considered as potential candidates in numerous low frequency applications, including micro-valves, micro-optical instrumentation and micro-robotics.

  5. 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. PMID:24816462

  6. 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. PMID:18497162

  7. 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

  8. 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...

  9. Investigation of Room Temperature Oxidation of Cu in Air by Yoneda-XAFS

    SciTech Connect

    Keil, P.; Luetzenkirchen-Hecht, D.; Frahm, R.

    2007-02-02

    The structure of thin copper oxide layers which are formed on metallic Cu due to the exposure to air are investigated with Yoneda-XAFS and ReflEXAFS. The measured Yoneda-XAFS data were compared to quantitative model calculations in the framework of the distorted wave Born approximation (DWBA) assuming different model structures for the oxide layer. Yoneda-XAFS fine structure spectra measured for various different grazing angles show that the experimental data are best described by a model structure consisting of a duplex type oxide layer with an outer layer of CuO (tenorite) in direct contact with the gas atmosphere and an inner Cu2O (cuprite) layer at the interface to the underlying Cu metal.

  10. 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.

  11. 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

  12. Laboratory validation and field verification of a new passive air monitoring badge for sampling ethylene oxide in air.

    PubMed

    Kring, E V; Damrell, D J; Basilio, A N; McGibney, P D; Douglas, J J; Henry, T J; Ansul, G R

    1984-10-01

    A new diffusion colorimetric air monitoring badge for sampling ethylene oxide is described. The Du Pont Pro-Tek C-70 badge has been laboratory validated over the range of 4-375 ppm-hours (0.5-47 ppm on an 8-hour TWA) using standard spectrophotometer readout in 1 centimeter (10 mm) cells. The lower range can be extended to 2 ppm-hours (0.25 ppm) by using 4 cm (40 mm) cells. The badge has an overall sampling and analytical method accuracy of +/- 13.5%. It meets NIOSH accuracy criteria and has a mean coefficient of variation CVT = 0.059. The badge has no temperature, pressure, relative humidity or face velocity effects over practical ranges. The response time is adequate to sample peak concentrations over short time periods. The badge may be used to determine ambient formaldehyde levels if suspected to be present along with ethylene oxide. Badges are shown to agree very well with the industry accepted and proposed ASTM pump/charcoal tube method in three extensive plant field tests. Badges were more precise than the charcoal tube/pump method in all field tests conducted. PMID:6496316

  13. 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...

  14. 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.

  15. FINAL REPORT. FUNDAMENTAL CHEMISTRY AND THERMODYNAMICS OF HYDROTHERMAL OXIDATION PROCESSES

    EPA Science Inventory

    The goal of this project was to address issues of fundamental chemistry and thermodynamic properties that currently limit the applicability of hydrothermal oxidation processes to the treatment of hazardous and radioactive DOE wastes. The primary issues are related to corrosion, i...

  16. 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.

  17. 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.

  18. Direct reduction processes for titanium oxide in molten salt

    NASA Astrophysics Data System (ADS)

    Suzuki, Ryosuke O.

    2007-02-01

    Molten salt electrolysis using CaCl2 is employed to produce pure titanium and its alloys directly from TiO2 and a mixture of elemental oxides, respectively, as an alternate to the Kroll process. This is because CaO, which is a reduction by-product, is highly soluble in CaCl2. Good-quality titanium containing only a small amount of residual oxygen has been successfully produced and scaled to industrial levels. Thermochemical and electrochemical bases are reviewed to optimize the process conditions. Several processes using molten salt are being examined for future progress in titanium processing.

  19. Development studies of a novel wet oxidation process

    SciTech Connect

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

    1995-12-01

    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. There is a need for non-combustion processes with a wide application range to treat the large majority of these waste forms. The non-combustion process should also be safe, effective, cost-competitive, permit-able, and preferrably mobile. This paper describes the DETOX process of organic waste oxidation.

  20. 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.

  1. Squaraine based solution processed inverted bulk heterojunction solar cells processed in air.

    PubMed

    Varma, P C Reshmi; Namboothiry, Manoj A G

    2016-02-01

    Inverted bulk heterojunction solar cells based on low temperature solution processed squaraine (SQ) and [6,6]-phenyl C71 butyric acid methyl-ester (PC71BM) with varying blend ratios were made in air. An optimized bulk heterojunction device of SQ and PC71BM (with a blend ratio of 1 : 6) showed a power conversion efficiency (PCE) of 2.45% with an incident photon to current conversion efficiency of 65% at 680 nm and a spectral window extending to the NIR region. The devices also showed an enhanced PCE value of 4.12% upon continuous illumination from an AM1.5G light source of intensity 1 Sun. The intensity dependent photocurrent studies showed a monomolecular recombination mechanism in the photovoltaic device performance. The device stored in air showed reasonable stability for a period of one month. PMID:26426261

  2. 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.

  3. 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...

  4. Thermal Behavior Study of the MoVTeNb Oxide Catalyst for Selective Oxidation Process

    NASA Astrophysics Data System (ADS)

    Idris, R.; Hamid, S. B. Abd.

    2009-06-01

    Several parameters involved in preparing the multi metal oxide (MMO) catalysts (Mo1V0.3Te0.23Nb0.12Ox) 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, TeMo5O16, V0.95Mo0.97O5 and Mo5O14 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.

  5. 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.

  6. 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.

  7. Determination of hexavalent chromium in ambient air: A story of method induced Cr(III) oxidation

    NASA Astrophysics Data System (ADS)

    Tirez, Kristof; Silversmit, Geert; Bleux, Nico; Adriaensens, Elke; Roekens, Edward; Servaes, Kelly; Vanhoof, Chris; Vincze, Laszlo; Berghmans, Patrick

    2011-09-01

    The accuracy of the determination of Cr(VI) in ambient particulate matter remains a challenge from the point of view of minimal Cr species interconversion. Knowledge of this method induced oxidation and reduction is particularly relevant for the determination of Cr(VI) in ambient particulate matter, as the level of observed Cr(III) oxidation (average of 1.7% in this study) can contribute significantly to the monitored range of measured Cr(VI) in PM 10. For Cr concentrations in PM 10 > 10 ng Cr m -3, this method induced oxidation could lead to false positive exceeding of an air quality guideline value of 0.2 ng Cr(VI) m -3 in PM 10. The median daily Cr(VI) concentration in PM 10 measured over a monitoring period of more than 2 months at two locations close to a stainless steel factory amounted to 0.9 ng Cr(VI) m -3 and 0.27 ng Cr(VI) m -3. Average daily Cr(VI)/Cr ratios in PM 10 of 3.5% and 2.6% were measured at these locations. The described monitoring for the determination of Cr(VI) in ambient air via alkaline impregnated filters is sensitive (method detection limit of 0.015 ng Cr(VI) m -3) and reproducible (precision of the method ˜25%). The average Cr(VI) recovery of 75% strongly indicates the effects of ambient sampling conditions and ambient particles on the Cr(VI) recoveries. The stability of the Cr(VI) and the Cr(III) spike on 0.12 M NaHCO 3 impregnated filters observed with XANES, indicates that the alkaline extraction of the filter in combination with the sampled air matrix is likely to induce the Cr conversions. The XANES spectra shows further that a Cr-spinel is the predominant component of Cr in ambient air PM 10 at the monitored locations.

  8. Studies on the regeneration of sulfided iron oxide sorbent with steam-air mixtures. Final technical report

    SciTech Connect

    Tamhankar, S.S.

    1982-10-01

    The work reported here was performed as a continuation of studies conducted previously at West Virginia University (WVU), Department of Chemical Engineering on a hot-fuel-gas desulfurization process using a regenerable iron oxide-silica sorbent. The overall process consists of two stages: the absorption or the H/sub 2/S removal stage and the sorbent regeneration stage. In the absorption stage the iron oxide reacts with H/sub 2/S to form iron sulfide. For regeneration of the sulfided sorbent, various schemes have been proposed. Studies at WVU have been aimed at identifying the important reactions involved in absorption and regeneration stages, elucidating their mechanisms and investigating detailed kinetics. In the first two phases of the study, reactions in H/sub 2/S absorption and in sorbent regeneration by air/SO/sub 2/ were investigated. This report addresses regeneration of the sulfided sorbent using steam-air mixtures. Experiments were conducted in a thermo-gravimetric analyzer (TGA) apparatus. The weight changes were recorded as a function of time during the reactions of iron sulfide (in the presulfided sorbent) with nitrogen-stream and air-steam mixtures. In addition, several solid samples at different conversion levels were anlayzed by LECO sulfur anlaysis technique and by Mossbauer spectroscopy. Based on these results, a reaction mechanism has been postulated. Additional work is necessary to investigate the gas-phase reactions which may be taking place simultaneously in a fixed - or a fluidized-bed reactor, and to formulate the overall reaction scheme. 14 figures, 3 tables.

  9. 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

  10. 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.

  11. A comparison of single oxidants versus advanced oxidation processes as chlorine-alternatives for wild blueberry processing (Vaccinium angustifolium).

    PubMed

    Crowe, Kristi M; Bushway, Alfred A; Bushway, Rodney J; Davis-Dentici, Katherine; Hazen, Russell A

    2007-05-01

    Advanced oxidation processes and single chemical oxidants were evaluated for their antimicrobial efficacy against common spoilage bacteria isolated from lowbush blueberries. Predominant bacterial flora were identified using biochemical testing with the assessment of relative abundance using non-selective and differential media. Single chemical oxidants evaluated for postharvest processing of lowbush blueberries included 1% hydrogen peroxide, 100 ppm chlorine, and 1 ppm aqueous ozone while advanced oxidation processes (AOPs) included combinations of 1% hydrogen peroxide/UV, 100 ppm chlorine/UV, and 1 ppm ozone/1% hydrogen peroxide/UV. Enterobacter agglomerans and Pseudomonas fluorescens were found to comprise 90-95% of the bacterial flora on lowbush blueberries. Results of inoculation studies reveal significant log reductions (p< or 5) in populations of E. agglomerans and P. fluorescens on all samples receiving treatment with 1% hydrogen peroxide, 1% hydrogen peroxide/UV, 1 ppm ozone, or a combined ozone/hydrogen peroxide/UV treatment as compared to chlorine treatments and unwashed control berries. Although population reductions approached 2.5 log CFU/g, microbial reductions among these treatments were not found to be significantly different (p< or 5) from each other despite the synergistic potential that should result from AOPs; furthermore, as a single oxidant, UV inactivation of inoculated bacteria was minimal and did not prove effective as a non-aqueous bactericidal process for fresh pack blueberries. Overall, results indicate that hydrogen peroxide and ozone, as single chemical oxidants, are as effective as AOPs and could be considered as chlorine-alternatives in improving the microbiological quality of lowbush blueberries. PMID:17350128

  12. 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

  13. 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.

  14. 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.

  15. Final report on international comparison CCQM-K68: Nitrous oxide in synthetic air

    NASA Astrophysics Data System (ADS)

    Lee, Jinbok; Lee, Jeongsoon; Moon, Dongmin; Seog Kim, Jin; Wessel, Rob; Aoki, Nobuyuki; Kato, Kenji; Guenther, Frank; Rhoderick, George; Konopelko, L. A.; Han, Qiao; Hall, Brad

    2011-01-01

    Nitrous oxide (N2O) is one of six greenhouse gases that are regulated by the Kyoto Protocol and has a Global Warming Potential (GWP) that is 296 times that of carbon dioxide. Global levels of nitrous oxide have increased at a rate of 0.25%/yr (0.8 ppb/yr) during the last ten years. In order to monitor levels of nitrous oxide in the atmosphere, it is necessary to use measurement standards with demonstrated equivalence at the highest level of accuracy. This report describes the results of a key comparison of standard gas mixtures of nitrous oxide in synthetic air at an amount fraction of 320 nmol/mol. This key comparison is part of the programme of the Gas Analysis Working Group (GAWG) of the CCQM to demonstrate the equivalence of the standards and measurement capabilities of the NMIs for greenhouse gases. It will support the development of measurement capability at the NMIs for nitrous oxide with uncertainties within the target set by the Global Atmospheric Watch (GAW) programme of the WMO for its global monitoring networks. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  16. Catalytic and non-catalytic wet air oxidation of sodium dodecylbenzene sulfonate: kinetics and biodegradability enhancement.

    PubMed

    Suárez-Ojeda, María Eugenia; Kim, Jungkwon; Carrera, Julián; Metcalfe, Ian S; Font, Josep

    2007-06-18

    Wet air oxidation (WAO) and catalytic wet air oxidation (CWAO) were investigated as suitable precursors for the biological treatment of industrial wastewater containing sodium dodecylbenzene sulfonate (DBS). Two hours WAO semi-batch experiments were conducted at 15 bar of oxygen partial pressure (P(O2)) and at 180, 200 and 220 degrees C. It was found that the highest temperature provides appreciable total organic carbon (TOC) and chemical oxygen demand (COD) abatement of about 42 and 47%, correspondingly. Based on the main identified intermediates (acetic acid and sulfobenzoic acid) a reaction pathway for DBS and a kinetic model in WAO were proposed. In the case of CWAO experiments, seventy-two hours tests were done in a fixed bed reactor in continuous trickle flow regime, using a commercial activated carbon (AC) as catalyst. The temperature and P(O2) were 140-160 degrees C and 2-9 bar, respectively. The influence of the operating conditions on the DBS oxidation, the occurrence of oxidative coupling reactions over the AC, and the catalytic activity (in terms of substrate removal) were established. The results show that the AC without any supported active metal behaves bi-functional as adsorbent and catalyst, giving TOC conversions up to 52% at 160 degrees C and 2 bar of P(O2), which were comparable to those obtained in WAO experiments. Respirometric tests were completed before and after CWAO and to the main intermediates identified through the WAO and CWAO oxidation route. Then, the readily biodegradable COD (COD(RB)) of the CWAO and WAO effluents were found. Taking into account these results it was possible to compare whether or not the CWAO or WAO effluents were suitable for a conventional activated sludge plant inoculated with non adapted culture. PMID:17363148

  17. Exposure to Ultrafine Particles from Ambient Air and Oxidative Stress–Induced DNA Damage

    PubMed Central

    Bräuner, Elvira Vaclavik; Forchhammer, Lykke; Møller, Peter; Simonsen, Jacob; Glasius, Marianne; Wåhlin, Peter; Raaschou-Nielsen, Ole; Loft, Steffen

    2007-01-01

    Background Particulate matter, especially ultrafine particles (UFPs), may cause health effects through generation of oxidative stress, with resulting damage to DNA and other macromolecules. Objective We investigated oxidative damage to DNA and related repair capacity in peripheral blood mononuclear cells (PBMCs) during controlled exposure to urban air particles with assignment of number concentration (NC) to four size modes with average diameters of 12, 23, 57, and 212 nm. Design Twenty-nine healthy adults participated in a randomized, two-factor cross-over study with or without biking exercise for 180 min and with exposure to particles (NC 6169-15362/cm3) or filtered air (NC 91-542/cm3) for 24 hr. Methods The levels of DNA strand breaks (SBs), oxidized purines as formamidopyrimidine DNA glycolase (FPG) sites, and activity of 7,8-dihydro-8-oxoguanine-DNA glycosylase (OGG1) in PBMCs were measured by the Comet assay. mRNA levels of OGG1, nucleoside diphosphate linked moiety X-type motif 1 (NUDT1), and heme oxygenase-1 (HO1) were determined by real-time reverse transcriptase–polymerase chain reaction. Results Exposure to UFPs for 6 and 24 hr significantly increased the levels of SBs and FPG sites, with a further insignificant increase after physical exercise. The OGG1 activity and expression of OGG1, NUDT1, and HO1 were unaltered. There was a significant dose–response relationship between NC and DNA damage, with the 57-nm mode as the major contributor to effects. Concomitant exposure to ozone, nitrogen oxides, and carbon monoxide had no influence. Conclusion Our results indicate that UFPs, especially the 57-nm soot fraction from vehicle emissions, causes systemic oxidative stress with damage to DNA and no apparent compensatory up-regulation of DNA repair within 24 hr. PMID:17687444

  18. 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. PMID:27321041

  19. Decolorization and mineralization of Allura Red AC aqueous solutions by electrochemical advanced oxidation processes.

    PubMed

    Thiam, Abdoulaye; Sirés, Ignasi; Garrido, José A; Rodríguez, Rosa M; Brillas, Enric

    2015-06-15

    The decolorization and mineralization of solutions containing 230 mg L(-1) of the food azo dye Allura Red AC at pH 3.0 have been studied upon treatment by electrochemical oxidation with electrogenerated H2O2 (EO-H2O2), electro-Fenton (EF) and photoelectro-Fenton (PEF). Experiments were performed with a stirred tank reactor containing a boron-doped diamond (BDD) or Pt anode and an air-diffusion cathode to generate H2O2. The main oxidants were hydroxyl radicals formed at the anode surface from water oxidation and in the bulk from Fenton's reaction between H2O2 and added Fe(2+). The oxidation ability increased in the sequence EO-H2O2 < EF < PEF and faster degradation was always obtained using BDD. PEF process with BDD yielded almost total mineralization following similar trends in SO4(2-), ClO4(-) and NO3(-) media, whereas in Cl(-) medium, mineralization was inhibited by the formation of recalcitrant chloroderivatives. GC-MS analysis confirmed the cleavage of the −N=N− bond with formation of two main aromatics in SO4(2-) medium and three chloroaromatics in Cl(-) solutions. The effective oxidation of final oxalic and oxamic acids by BDD along with the photolysis of Fe(III)-oxalate species by UVA light accounted for the superiority of PEF with BDD. NH4(+), NO3(-) and SO4(2-) ions were released during the mineralization. PMID:25734532

  20. 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

  1. Gas chromatograph analysis on closed air and nitrogen oxide storage atmospheres of recalcitrant seeds of Quercus Alba

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Storage of recalcitrant seeds remains an unsolved problem. This study investigated the quantitative gas analysis of nitrous oxide (N2O) and air atmospheres on the recalcitrant seeds of Quercus alba by using gas chromatograph. Ten seeds were placed in each sealed atmospheric system of air and 98/2% N...

  2. 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... panel membership include: (a) Scientific and/or technical expertise, knowledge, and experience...

  3. Vapor-gel processing and applications in oxide film depositions

    SciTech Connect

    Chour, K.W.; Xu, R.; Takada, T.

    1995-12-31

    The Vapor-gel processing of oxide films is discussed for the prototypic system of LiTa(OBut{sup n}){sub 6}-LiTaO{sub 3}. It is found that the hydrolysis-polycondensation reaction scheme, commonly used in Sol-gel processing, can be used in a vapor deposition environment. High quality films can be deposited at low temperatures. We present some initial results regarding this deposition method and discuss its advantages and disadvantages as compared with Sol-gel processing and typical MOCVD.

  4. 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.

  5. Ruthenium-based electrocatalysts supported on reduced graphene oxide for lithium-air batteries.

    PubMed

    Jung, Hun-Gi; Jeong, Yo Sub; Park, Jin-Bum; Sun, Yang-Kook; Scrosati, Bruno; Lee, Yun Jung

    2013-04-23

    Ruthenium-based nanomaterials supported on reduced graphene oxide (rGO) have been investigated as air cathodes in non-aqueous electrolyte Li-air cells using a TEGDME-LiCF3SO3 electrolyte. Homogeneously distributed metallic ruthenium and hydrated ruthenium oxide (RuO2·0.64H2O), deposited exclusively on rGO, have been synthesized with average size below 2.5 nm. The synthesized hybrid materials of Ru-based nanoparticles supported on rGO efficiently functioned as electrocatalysts for Li2O2 oxidation reactions, maintaining cycling stability for 30 cycles without sign of TEGDME-LiCF3SO3 electrolyte decomposition. Specifically, RuO2·0.64H2O-rGO hybrids were superior to Ru-rGO hybrids in catalyzing the OER reaction, significantly reducing the average charge potential to ∼3.7 V at the high current density of 500 mA g(-1) and high specific capacity of 5000 mAh g(-1). PMID:23540570

  6. 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

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

    DOE PAGESBeta

    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 small

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

    DOE PAGESBeta

    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

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

    SciTech Connect

    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.

    2016-01-01

    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

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Thin porous indium tin oxide nanoparticle films: effects of annealing in vacuum and air

    NASA Astrophysics Data System (ADS)

    Ederth, J.; Hultåker, A.; Niklasson, G. A.; Heszler, P.; van Doorn, A. R.; Jongerius, M. J.; Burgard, D.; Granqvist, C. G.

    2005-11-01

    Electrical and optical properties were investigated in porous thin films consisting of In2O3:Sn (indium tin oxide; ITO) nanoparticles. The temperature-dependent resistivity was successfully described by a fluctuation-induced tunneling model, indicating a sample morphology dominated by clusters of ITO nanoparticles separated by insulating barriers. An effective-medium model, including the effect of ionized impurity scattering, was successfully fitted to measured reflectance and transmittance. Post-deposition treatments were carried out at 773 K for 2 h in both air and vacuum. It is shown that vacuum annealing increases either the barrier width or the area between two conducting clusters in the samples and, furthermore, an extra optical absorption occurs close to the band gap. A subsequent air annealing then reduces the effect of the barriers on the electrical properties and diminishes the absorption close to the band gap.

  15. Microleakage on Class V glass ionomer restorations after cavity preparation with aluminum oxide air abrasion.

    PubMed

    Corona, Silmara Aparecida Milori; Borsatto, Maria Cristina; Rocha, Renata Andréa Salvitti de Sá; Palma-Dibb, Regina Guenka

    2005-01-01

    This in vitro study assessed the marginal microleakage on class V cavities prepared with aluminum oxide air abrasion and restored with different glass ionomer cements. The cavities were prepared on the buccal and lingual surfaces of 15 sound third molars with an air- abrasion device (Kreativ Mach 4.1; New Image) using a 27.5-microm aluminum oxide particle stream, and were assigned to 3 groups of 10 cavities each. The restorative materials were: group I, a conventional glass ionomer cement (Ketac-Fil); groups II and III, resin-modified glass ionomer cements (Vitremer R and Fuji II LC, respectively). After placement of the restorations, the teeth were stored in distilled water at 37 degrees C for 24 h, polished and then submitted to a thermocycling regimen of 500 cycles, isolated, immersed in 0.2% Rhodamine B solution for 24 h, included and serially sectioned. Microleakage was assessed by viewing the specimens under an optical microscope connected to a color video camera and a computer. The images obtained were digitized and analyzed for microleakage using software that allows for a standard quantitative assessment of dye penetration in millimeters. Statistical analysis was done using the Kruskall-Wallis and Wilcoxon tests. Means of dye penetration (%) were: occlusal - I: 25.76 +/- 34.35, II: 20.00 +/- 42.16, III: 28.25 +/- 41.67; cervical - I: 23.72 +/- 41.84; II: 44.22 +/- 49.69, III: 39.27 +/- 50.74. No statistically significant differences (p>0.05) were observed among either the glass ionomer cements or the margins. In conclusion, class V cavities restored with either conventional or resin-modified glass ionomer cements after preparation with aluminum oxide air abrasion did not show complete sealing at the enamel and dentin/cementum margins. PMID:16113931

  16. 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.

  17. 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.

  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. Process for the reduction of nitrogen oxides in an effluent

    SciTech Connect

    Epperly, W.R.; Sullivan, J.C.

    1988-09-13

    A process is described for reducing the concentration of nitrogen oxides in an effluent from the combustion of a carbonaceous fuel, which process comprises injecting into the effluent ammonia and an enhancer selected from the group consisting of hexamethylenetetramine, a lower carbon alcohol, a hydroxyl amino hydrocarbon, sugar, furfural, furfural derivatives, an amino acid, a protein-containing composition, mixtures of ortho-, meta-, and para-methyl phenols, guanidine, guanidine carbonate, biguanidine, guanylurea sulfate, melamine, dicyandiamide, calcium cyanamide, biuret, 1,1'-azobisformamide, methylol urea, methylol urea-urea condensation product, dimethylol urea, methyl urea, dimethyl urea, and mixtures thereof, at an effluent temperature above about 1300/sup 0/F and a molar ratio of nitrogen in the ammonia and enhancer to the baseline nitrogen oxides level of about 1:5 to about 6:1 wherein the excess of oxygen in the effluent is no greater than about 6%.

  20. Removal of residual pharmaceuticals from aqueous systems by advanced oxidation processes.

    PubMed

    Klavarioti, Maria; Mantzavinos, Dionissios; Kassinos, Despo

    2009-02-01

    Over the past few years, pharmaceuticals are considered as an emerging environmental problem due to their continuous input and persistence to the aquatic ecosystem even at low concentrations. Advanced oxidation processes (AOPs) are technologies based on the intermediacy of hydroxyl and other radicals to oxidize recalcitrant, toxic and non-biodegradable compounds to various by-products and eventually to inert end-products. The environmental applications of AOPs are numerous, including water and wastewater treatment (i.e. removal of organic and inorganic pollutants and pathogens), air pollution abatement and soil remediation. AOPs are applied for the abatement of pollution caused by the presence of residual pharmaceuticals in waters for the last decade. In this light, this paper reviews and assesses the effectiveness of various AOPs for pharmaceutical removal from aqueous systems. PMID:18760478

  1. Incipient oxidation kinetics of alloy 617 and residual stress of the oxide scale formed in air at temperatures between 850 and 1000 °C

    NASA Astrophysics Data System (ADS)

    Tung, Hsiao-Ming; Stubbins, James F.

    2012-05-01

    The purpose of this study was to investigate incipient oxidation of alloy 617 in air in the temperature range of 850-1000 °C. Alloy 617 exhibited a two-stage oxidation kinetics and followed Wagner's parabolic law. The activation energy for the first stage and the second stage are 271.2 and 318 kJ/mol, respectively. The transition time between the two stages decreased as the oxidation temperature increased. X-ray diffraction (XRD) revealed that the oxide phase is chromium oxide, Cr2O3, over the entire temperature range. The results of residual stress measurements showed that the grown-in stresses of the scale are tensile in nature. This may be due to the crystallite coalescence during the growth of the oxide. The measured residual stress of the substrate decreases with increasing oxidation temperature which may be attributed to the formation of pores or voids within the substrate after exposure to high temperatures.

  2. 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).

  3. 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).

  4. Osteoconductivity and Hydrophilicity of TiO2 Coatings on Ti Substrates Prepared by Different Oxidizing Processes

    PubMed Central

    Yamamoto, Dai; Kawai, Ikki; Kuroda, Kensuke; Ichino, Ryoichi; Okido, Masazumi; Seki, Azusa

    2012-01-01

    Various techniques for forming TiO2 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, TiO2 coatings were prepared using the following three processes: anodizing in 0.1 M H3PO4 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 TiO2 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 RB-I value) after 14 d implantation in rats' tibias. Anatase was formed by anodizing and rutile by thermal oxidation, but the difference in the TiO2 crystal structure did not influence the osteoconductivity. Anodized TiO2 coatings were hydrophilic, but thermally oxidized TiO2 coatings were less hydrophilic than anodized TiO2 coatings because they lacked in surface OH groups. The TiO2 coating process using anodizing without thermal oxidation gave effective improvement of the osteoconductivity of Ti samples. PMID:23316128

  5. Oxidative Nitration of Styrenes for the Recycling of Low-Concentrated Nitrogen Dioxide in Air.

    PubMed

    Hofmann, Dagmar; de Salas, Cristina; Heinrich, Markus R

    2015-09-21

    The oxidative nitration of styrenes in ethyl acetate represents a metal-free, environmentally friendly, and sustainable technique to recover even low concentrations of NO2 in air. Favorable features are that the product mixture comprising nitroalcohols, nitroketones, and nitro nitrates simplifies at lower concentrations of NO2 . Experiments in a miniplant-type 10 L wet scrubber demonstrated that the recycling technique is well applicable on larger scales at which initial NO2 concentrations of >10 000 ppm were reliably reduced to less than 40 ppm. PMID:26284827

  6. ELECTROCHEMICAL ADVANCED OXIDATION PROCESS UTILIZING NB-DOPED TIO2 ELECTRODES

    EPA Science Inventory

    An electrochemical advanced oxidation process has been developed utilizing electrodes which generate hydroxyl free radical (HO) by oxidizing water. All substrates tested are oxidized, mostly with reaction rates proportional to the corresponding rate constants for reaction with hy...

  7. ELECTROCHEMICAL ADVANCED OXIDATION PROCESS UTILIZING NB-DOPED TIO2 ELECTRODES

    EPA Science Inventory

    An electrochemical advanced oxidation process has been developed, utilizing electrodes which generate hydroxyl free radical (HO) by oxidizing water. All substrates tested are oxidized, mostly with reaction rates proportional to the corresponding rate constants for reaction with h...

  8. 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}.

  9. 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.

  10. Lipid oxidation volatiles absent in milk after selected ultrasound processing.

    PubMed

    Juliano, Pablo; Torkamani, Amir Ehsan; Leong, Thomas; Kolb, Veronika; Watkins, Peter; Ajlouni, Said; Singh, Tanoj Kumar

    2014-11-01

    Ultrasonic processing can suit a number of potential applications in the dairy industry. However, the impact of ultrasound treatment on milk stability during storage has not been fully explored under wider ranges of frequencies, specific energies and temperature applications. The effect of ultrasonication on lipid oxidation was investigated in various types of milk. Four batches of raw milk (up to 2L) were sonicated at various frequencies (20, 400, 1000, 1600 and 2000kHz), using different temperatures (4, 20, 45 and 63°C), sonication times and ultrasound energy inputs up to 409kJ/kg. Pasteurized skim milk was also sonicated at low and high frequency for comparison. In selected experiments, non-sonicated and sonicated samples were stored at 4°C and were drawn periodically up to 14days for SPME-GCMS analysis. The cavitational yield, characterized in all systems in water, was highest between 400kHz and 1000kHz. Volatile compounds from milk lipid oxidation were detected and exceeded their odor threshold values at 400kHz and 1000kHz at specific energies greater than 271kJ/kg in raw milk. However, no oxidative volatile compounds were detected below 230kJ/kg in batch systems at the tested frequencies under refrigerated conditions. Skim milk showed a lower energy threshold for oxidative volatile formation. The same oxidative volatiles were detected after various passes of milk through a 0.3L flow cell enclosing a 20kHz horn and operating above 90kJ/kg. This study showed that lipid oxidation in milk can be controlled by decreasing the sonication time and the temperature in the system depending on the fat content in the sample among other factors. PMID:24704065

  11. 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

  12. Application of an adsorptive-thermocatalytic process for BTX removal from polluted air flow

    PubMed Central

    2014-01-01

    Background Zero valent iron and copper oxide nanoparticles (30-60 nm) were coated on a bed of natural zeolite (Clinoptilolite) with 1-2 mm grains and arranged as a dual filter in a stainless steel cylindrical reactor (I.D 4.5 cm and L = 30 cm) to investigating the coated bed removal efficiency for BTX. The experiments were conducted in three steps. First, with an air flow of 1.5 L/min and temperature range of 38 (ambient temperature) to 600°C the BTX removal and mineralization was surveyed. Then, in an optimized temperature the effect of flow rate and pollution loading rate were surveyed on BTX removal. Results The BTX removal at 300 and 400°C were respectively up to 87.47% and 94.03%. Also in these temperatures respectively 37.21% and 90.42% of BTX mineralization were achieved. In the retention times of 14.1 s and 7.05 s, respectively 96.18% and 78.42% of BTX was removed. Conclusions According to the results, this adsorptive-thermocatalytic process with using Clinoptilolite as an adsorbent bed and combined Fe0 and Cu2O nanoparticles as catalysts can be an efficient and competitive process in the condition of high flow rate and high pollution loading rate with an adequate process temperature of 350°C. PMID:24955244

  13. Budgets for nocturnal VOC oxidation by nitrate radicals aloft during the 2006 Texas Air Quality Study

    NASA Astrophysics Data System (ADS)

    Brown, Steven S.; Dubé, William P.; Peischl, Jeff; Ryerson, Thomas B.; Atlas, Elliot; Warneke, Carsten; de Gouw, Joost A.; Te Lintel Hekkert, Sacco; Brock, Charles A.; Flocke, Frank; Trainer, Michael; Parrish, David D.; Feshenfeld, Frederick C.; Ravishankara, A. R.

    2011-12-01

    Industrial emissions in Houston, Texas, and along the U.S. Gulf Coast are a large source of highly reactive anthropogenic volatile organic compounds (VOCs), principally alkenes, that affect air quality in that region. Nighttime oxidation by either O3 or NO3 removes these VOCs. This paper presents a regional analysis of nighttime P-3 flights during the 2006 Texas Air Quality Study (TexAQS) to quantify the loss rates and budgets for both NO3 and highly reactive VOC. Mixing ratios and production rates of NO3 were large, up to 400 parts per trillion by volume (pptv) and 1-2 parts per billion by volume (ppbv) per hour, respectively. Budgets for NO3 show that it was lost primarily to reaction with VOCs, with the sum of anthropogenic VOCs (30-54%) and isoprene (10-50%) being the largest contributors. Indirect loss of NO3 to N2O5 hydrolysis was of lesser importance (14-28%) but was the least certain due to uncertainty in the aerosol uptake coefficient for N2O5. Reaction of NO3 with peroxy radicals was a small but nonzero contribution to NO3 loss but was also uncertain because there were no direct measurements of peroxy radicals. Net VOC oxidation rates were rapid (up to 2 ppbv VOC h-1 in industrial plumes) and were dominated by NO3, which was 3-5 times more important as an oxidant than O3. Plumes of high NO3 reactivity (i.e., short steady state lifetimes, on the order of 1 min) identified the presence of concentrated emissions of highly reactive VOCs from the Houston Ship Channel (HSC), which, depending on the particular VOC, may be efficiently oxidized during overnight transport.

  14. Air oxidation of Zircaloy-4 in the 600-1000 °C temperature range: Modeling for ASTEC code application

    NASA Astrophysics Data System (ADS)

    Coindreau, O.; Duriez, C.; Ederli, S.

    2010-10-01

    Progress in the treatment of air oxidation of zirconium in severe accident (SA) codes are required for a reliable analysis of severe accidents involving air ingress. Air oxidation of zirconium can actually lead to accelerated core degradation and increased fission product release, especially for the highly-radiotoxic ruthenium. This paper presents a model to simulate air oxidation kinetics of Zircaloy-4 in the 600-1000 °C temperature range. It is based on available experimental data, including separate-effect experiments performed at IRSN and at Forschungszentrum Karlsruhe. The kinetic transition, named "breakaway", from a diffusion-controlled regime to an accelerated oxidation is taken into account in the modeling via a critical mass gain parameter. The progressive propagation of the locally initiated breakaway is modeled by a linear increase in oxidation rate with time. Finally, when breakaway propagation is completed, the oxidation rate stabilizes and the kinetics is modeled by a linear law. This new modeling is integrated in the severe accident code ASTEC, jointly developed by IRSN and GRS. Model predictions and experimental data from thermogravimetric results show good agreement for different air flow rates and for slow temperature transient conditions.

  15. 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.

  16. 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

  17. 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

  18. 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.

  19. A comparison between conductive-diamond electrochemical oxidation and other advanced oxidation processes for the treatment of synthetic melanoidins.

    PubMed

    Cañizares, P; Hernández-Ortega, M; Rodrigo, M A; Barrera-Díaz, C E; Roa-Morales, G; Sáez, C

    2009-05-15

    In this study, three technologies classified as Advanced Oxidation Processes (Conductive-Diamond Electrochemical Oxidation (CDEO), ozonation and Fenton oxidation) have been compared to treat wastes produced in fermentation processes, and characterized by a significant color and a high organic load. Results of CDEO seem to strongly depend on the addition of an electrolyte salt, not only to decrease the energy cost but also to improve efficiency. The addition of sodium chloride as supporting electrolyte improves the removal percentages of organic load, indicating the important role of mediated oxidation processes carried out by the electrogenerated oxidants (hypochlorite). Fenton oxidation and ozonation seem to be less efficient, and mainly Fenton oxidation favors the accumulation of refractory compounds. The differences observed can be explained in terms of the contribution of hydroxyl radicals and other specific oxidation mechanisms involved in each technology. PMID:18789836

  20. Process for the reduction of nitrogen oxides in an effluent

    SciTech Connect

    Epperly, W.R.; Sullivan, J.C.; Sprague, B.N.

    1989-07-04

    This patent describes a process for the reduction of the concentration of nitrogen oxides in the effluent from the combustion of a carbonaceous fuel. The process comprises introducing a treatment agent which comprises a composition selected from the group consisting of NH/sub 4/-lignosulfonate, calcium lignosulfonate, 2-furoic acid, 1,3 dioxolane, tetrahydrofuran, furfurylamine, furfurylalcohol, gluconic acid, citric acid, n-butyl acetate, 1,3 butylene glycol, methylal, tetrahydrofuryl alcohol, furan, fish oil, coumalic acid, furfuryl acetate, tetrahydrofuran 2,3,4,5-tetracarboxylic acid, tetrahydrofurylamine, furylacrylic acid, tetrahydropyran, 2,5-furandimethanol, mannitol, hexamethylenediamine, barbituric acid, acetic anhydride, oxalic acid, mucic acid and d-galactose.

  1. 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. PMID:24873706

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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

    2016-06-01

    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.

  10. 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.

  11. Clean-air legislation will buoy U. S. gas processing

    SciTech Connect

    Haun, R.R.; Ellington, E.E.; Otto, K.W. )

    1991-07-22

    This paper reports on the effects of recent U.S. clean-air legislation on NGL demand and pricing. Demand for all NGL products will be firm throughout the 1990s. Increased requirements for butane as methyl tertiary butyl ether (MTBE) feedstock will strengthen butane prices. Higher base-load requirements for propane in new NGL-based olefin plants will also have a positive impact on propane prices.

  12. Traffic-related air pollution and alveolar nitric oxide in southern California children.

    PubMed

    Eckel, Sandrah P; Zhang, Zilu; Habre, Rima; Rappaport, Edward B; Linn, William S; Berhane, Kiros; Zhang, Yue; Bastain, Theresa M; Gilliland, Frank D

    2016-05-01

    Mechanisms for the adverse respiratory effects of traffic-related air pollution (TRAP) have yet to be established. We evaluated the acute effects of TRAP exposure on proximal and distal airway inflammation by relating indoor nitric oxide (NO), a marker of TRAP exposure in the indoor microenvironment, to airway and alveolar sources of exhaled nitric oxide (FeNO).FeNO was collected online at four flow rates in 1635 schoolchildren (aged 12-15 years) in southern California (USA) breathing NO-free air. Indoor NO was sampled hourly and linearly interpolated to the time of the FeNO test. Estimated parameters quantifying airway wall diffusivity (DawNO) and flux (J'awNO) and alveolar concentration (CANO) sources of FeNO were related to exposure using linear regression to adjust for potential confounders.We found that TRAP exposure indoors was associated with elevated alveolar NO. A 10 ppb higher indoor NO concentration at the time of the FeNO test was associated with 0.10 ppb higher average CANO (95% CI 0.04-0.16) (equivalent to a 7.1% increase from the mean), 4.0% higher J'awNO (95% CI -2.8-11.3) and 0.2% lower DawNO (95% CI -4.8-4.6).These findings are consistent with an airway response to TRAP exposure that was most marked in the distal airways. PMID:26797034

  13. Oxidation, volatilization, and redistribution of molybdenum from TZM alloy in air

    SciTech Connect

    Smolik, G.R.; Petti, D.A.; McCarthy, K.A.; Schuetz, S.T.

    2000-01-01

    The excellent high temperature strength and thermal conductivity of molybdenum-base alloys provide attractive features for components in advanced magnetic and inertial fusion devices. Refractory metal alloys react readily with oxygen and other gases. Oxidized molybdenum in turn is susceptible to losses from volatile molybdenum trioxide species, MoO{sub 3}(m), in air and the hydroxide, MoO{sub 2}(OH){sub 2}, formed from water vapor. Transport of radioactivity by the volatilization, migration, and re-deposition of these volatile species during a potential accident involving a loss of vacuum or inert environment represents a safety issue. In this report the authors present experimental results on the oxidation, volatilization and re-deposition of molybdenum from TZM in flowing air between 400 and 800 C. These results are compared with calculations obtained from a vaporization mass transfer model using chemical thermodynamic data for vapor pressures of MoO{sub 3}(g) over pure solid MoO{sub 3} and an expression for the vapor pressures of MoO{sub 2}(OH){sub 2} from the literature. Calculations correlate well with experimental data.

  14. Oxidation, Volatilization, and Redistribution of Molybdenum from TZM Alloy in Air

    SciTech Connect

    Smolik, Galen Richard; Petti, David Andrew; Mccarthy, Kathryn Ann; Schuetz, Stanley Thomas

    2000-01-01

    The excellent high temperature strength and thermal conductivity of molybdenum-base alloys provide attractive features for components in advanced magnetic and inertial fusion devices. Refractory metal alloys react readily with oxygen and other gases. Oxidized molybdenum in turn is susceptible to losses from volatile molybdenum trioxide species, (MoO3)m, in air and the hydroxide, MoO2(OH)2, formed from water vapor. Transport of radioactivity by the volatilization, migration, and re-deposition of these volatile species during a potential accident involving a loss of vacuum or inert environment represents a safety issue. In this report we present experimental results on the oxidation, volatilization and re-deposition of molybdenum from TZM in flowing air between 400 and 800°C. These results are compared with calculations obtained from a vaporization mass transfer model using chemical thermodynamic data for vapor pressures of MoO3(g) over pure solid MoO3 and an expression for the vapor pressures of MoO2(OH)2 from the literature. Calculations correlate well with experimental data.

  15. Optimization of the development process for air sampling filter standards

    NASA Astrophysics Data System (ADS)

    Mena, RaJah Marie

    Air monitoring is an important analysis technique in health physics. However, creating standards which can be used to calibrate detectors used in the analysis of the filters deployed for air monitoring can be challenging. The activity of a standard should be well understood, this includes understanding how the location within the filter affects the final surface emission rate. The purpose of this research is to determine the parameters which most affect uncertainty in an air filter standard and optimize these parameters such that calibrations made with them most accurately reflect the true activity contained inside. A deposition pattern was chosen from literature to provide the best approximation of uniform deposition of material across the filter. Samples sets were created varying the type of radionuclide, amount of activity (high activity at 6.4 -- 306 Bq/filter and one low activity 0.05 -- 6.2 Bq/filter, and filter type. For samples analyzed for gamma or beta contaminants, the standards created with this procedure were deemed sufficient. Additional work is needed to reduce errors to ensure this is a viable procedure especially for alpha contaminants.

  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. 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.

  18. 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.

  19. Free Radical Reactions in Aqueous Solutions: Examples from Advanced Oxidation Processes for Wastewater from the Chemistry in Airborne Water Droplets

    NASA Astrophysics Data System (ADS)

    Baird, N. Colin

    1997-07-01

    Inorganic chemistry involving free radicals in aqueous solutions can be important in environmental processes. A common free radical reaction in aqueous solution is electron transfer, especially to the hydroxyl radical and to ozone. Hydrogen peroxide and free radicals related to it act as weak acids, so both their neutral and deprotonated forms must be considered in reactions. In Advanced Oxidation Processes, the hydroxyl radical concentration in water is greatly increased by reactions involving ozone and/or ultraviolet light. Irradiation of solid titanium dioxide can also be used to generate the radicals. The hydroxyl radicals are used in the Processes to initiate the oxidation of dissolved organic pollutants. Free radical reactions also play an important role in the chemistry of water droplets suspended in air in clouds and fogs. The radicals arise indirectly from the photoionization of dissolved organic compounds such as aldehydes and from the iron-catalyzed decomposition of dissolved hydrogen peroxide. They oxidize dissolved sulfur dioxide and certain organic compounds.

  20. Elemental composition and oxidative properties of PM(2.5) in Estonia in relation to origin of air masses - results from the ECRHS II in Tartu.

    PubMed

    Orru, Hans; Kimmel, Veljo; Kikas, Ulle; Soon, Argo; Künzli, Nino; Schins, Roel P F; Borm, Paul J A; Forsberg, Bertil

    2010-03-01

    Fine particulate matter (PM(2.5)) was sampled at an urban background site in Tartu, Estonia over one-year period during the ECRHS II study. The elemental composition of 71 PM(2.5) samples was analyzed for different chemical elements using energy-dispersive X-ray fluorescence spectrometry (ED-XRF). The oxidative activity of 36 samples was assessed by measuring their ability to generate hydroxyl radicals in the presence of hydrogen peroxide. The origin of air masses was determined by computing 96-hour back trajectories of air masses with the HYSPLIT Model. The trajectories of air masses were divided into four sectors according to geographical patterns: "Russia," "Eastern Europe," "Western Europe," and "Scandinavia." During the study period, approximately 30% of air masses originated from "Scandinavia." The other three sectors had slightly lower values (between 18 and 22%). In spring, summer, and winter, higher total PM levels originated from air masses from continental areas, namely "Russia" and "Eastern Europe" (18.51+/-7.33 and 19.96+/-9.23microg m(-3), respectively). In autumn, the PM levels were highest in "Western Europe". High levels of Fe, Ti, and AlCaSi (Al, Ca, and Si) were also detected in air masses from the Eurasian continent. The oxidative properties were correlated to the origin of air masses. The OH values were approximately 1.5 times higher when air masses originated from the direction of "Eastern Europe" or "Russia." The origin of measured particles was evaluated using principal component factor analysis. When comparing the PM(2.5) elemental composition with seasonal variation, factor scores, and other studies, the factors represent: (1) combustion of biomass; (2) crustal dust; (3) traffic; and (4) power plants and industrial processes associated with oil burning. The total PM(2.5) is driven mainly by biomass and industrial combustion (63%) and other unidentified sources (23%). Other sources of PM, such as crustal dust and traffic, contribute a total

  1. 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.

  2. Rate-ratio asymptotic analysis of methane-air diffusion-flame structure for predicting production of oxides of nitrogen

    SciTech Connect

    Hewson, J.C.; Williams, F.A.

    1999-05-01

    Production rates of oxides of nitrogen in laminar methane-air diffusion flames are addressed, with thermal, prompt, and nitrous oxide mechanisms taken into account, as well as consumption processes collectively termed reburn. For this purpose, it is necessary to extend the well-known four-step flame-chemistry description to six steps, with acetylene taken out of steady-state and one-step production of nitric oxide included. Emission indices are calculated as functions of the rate of scalar dissipation at the stoichiometric mixture fraction for near-atmospheric pressures and shown to be in reasonable agreement with results obtained from numerical integrations. The various mechanisms of NO{sub x} production and consumption are verified to be strongly dependent on the flame temperature and on superequilibrium concentrations of radicals, both fuel-derived and from hydrogen-oxygen chemistry; the flame-structure analysis was extended to provide sufficient accuracy in the prediction of these quantities. It was found that for flames in near-normal ambient atmospheres, the prompt mechanism usually is most important. For longer residence times, and especially for ambient pressures and temperatures above standard, the thermal mechanism was found to increase in importance, but this increase was calculated to be offset almost entirely by NO consumption through reburn reactions. Conditions that favor reburn were observed to be those where the ratio of radical concentrations to NO concentrations is small. Longer residence times and higher pressures were demonstrated to lead both to more complete heat release and to smaller superequilibrium radical concentrations whence the correspondence between thermal production and reburn. The nitrous oxide mechanism was found to be generally less important for the conditions considered here.

  3. 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).

  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. ZnO/MoO 3 mixed oxide nanotube: A highly efficient and stable catalyst for degradation of dye by air under room conditions

    NASA Astrophysics Data System (ADS)

    Huang, Jiguo; Wang, Xiaohong; Li, Sen; Wang, Yu

    2010-10-01

    As a continuation of our work to develop catalysts with high activity for catalytic air wet oxidation process under mild conditions, degradation of wastewater containing 0.3 g/L Safranin-T (ST) by air oxidation over ZnO/MoO 3 nanotube catalyst was studied. It was found the decolorization efficiency and the chemical oxygen demand (COD) removal of ST reached above 98% and 95%, respectively, within 18 min at room temperature and atmospheric pressure. And the organic pollutants were totally mineralized to simple inorganic species such as HCO 3-, Cl - and NO 3-, while the total organic carbon (TOC) decreased 99.3%. The structure and morphology of the catalyst after ten cycling runs showed that the catalyst was stable under such operating condition and the leaching test showed negligible leaching effect. This ZnO/MoO 3 nanotube is proved to be an active and stable heterogeneous catalyst in CWAO of ST under extremely mild conditions.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Nitric Oxide Regulation of Mitochondrial Processes: Commonality in Medical Disorders.

    PubMed

    Stefano, George B; Kream, Richard M

    2015-01-01

    The vital status of diverse classes of eukaryotic mitochondria is reflected by the high degree of evolutionary modification functionally linked to ongoing multifaceted organelle development. From this teleological perspective, a logistical enhancement of eukaryotic cellular energy requirements indicates a convergence of metabolic processes within the mitochondrial matrix for optimal synthesis of ATP from ADP and inorganic phosphate and necessitates an evolutionarily driven retrofit of the primordial endosymbiont bacterial plasma membrane into the inner mitochondrial membrane. The biochemical complexity of eukaryotic inner membrane electron transport complexes linked to temporally-defined, state-dependent, fluctuations in mitochondrial oxygen utilization is capable of generating deleterious reactive oxygen species. Within this functional context, an extensive neurochemical literature supports the role of the free radical gas nitric oxide (NO) as a key signaling molecule involved in the regulation of multiple aspects of mitochondrial respiration/oxidative phosphorylation. Importantly, the unique chemical properties of NO underlie its rapid metabolism in vivo within a mechanistic spectrum of small oxidative molecules, free and protein-bound thiol adducts, and reversible binding to ferrous heme iron centers. Recent compelling work has identified a medically relevant dual regulation pathway for mitochondrial NO expression mediated by traditionally characterized NO synthases (NOS) and by enzymatic reduction of available cellular nitrite pools by a diverse class of cytosolic and mitochondrial nitrite reductases. Accordingly, our short review presents selected medically-based discussion topics relating to multi-faceted NO regulation of mitochondrial functions in human health and disease states. PMID:26177568

  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. 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

  13. 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.

  14. 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. PMID:22339480

  15. Asphaltene Erosion Process in Air Plasma: Emission Spectroscopy and Surface Analysis for Air-Plasma Reactions

    NASA Astrophysics Data System (ADS)

    Martinez, H.; Flores, O.; C. Poveda, J.; Campillo, B.

    2012-04-01

    Optical emission spectroscopy (OES) was applied for plasma characterization during the erosion of asphaltene substrates. An amount of 100 mg of asphaltene was carefully applied to an electrode and exposed to air-plasma glow discharge at a pressure of 1.0 Torr. The plasma was generated in a stainless steel discharge chamber by an ac generator at a frequency of 60 Hz, output power of 50 W and a gas flow rate of 1.8 L/min. The electron temperature and ion density were estimated to be 2.15±0.11 eV and (1.24±0.05) × 1016 m-3, respectively, using a double Langmuir probe. OES was employed to observe the emission from the asphaltene exposed to air plasma. Both molecular band emission from N2, N+2, OH, CH, NH, O2 as well as CN, and atomic light emission from V and Hγ were observed and used to monitor the evolution of asphaltene erosion. The asphaltene erosion was analyzed with the aid of a scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX) detector. The EDX analysis showed that the time evolution of elements C, O, S and V were similar; and the chemical composition of the exposed asphaltenes remained constant. Particle size evolution was measured, showing a maximum size of 2307 μm after 60 min. This behavior is most likely related to particle agglomeration as a function of time.

  16. 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

  17. High temperature silver-palladium-copper oxide air braze filler metal

    NASA Astrophysics Data System (ADS)

    Darsell, Jens Tommy

    The Ag-CuO system is currently being investigated as the basis for an air braze filler metal alloy to be used in SOFC components. The system is of interest because unlike most braze alloys, it is capable of wetting a variety of ceramic materials while being applied in an air. This thesis work examined modification of Ag-CuO filler metal system by alloying with palladium to increase the use temperature of the resulting air braze alloy. Thermal analysis was performed to track changes in the solidus and liquidus temperatures for these alloys and determine equilibrium phase present as a function of temperature and composition. Sessile drop experiments were performed to investigate the effect of palladium addition on braze wetability. The influence of copper-oxide and palladium contents on brazed joint strength was characterized by a combination of four-point bend testing and fractography. From combined thermal analysis and quenched data it was found that both the liquidus and solidus increase with increasing palladium content, and the silver-rich miscibility gap boundary could be shifted by the addition of palladium. This was employed as a tool to study the effects of two-liquid phase formation on wetting behavior. In addition, a mass loss likely attributable to silver volatilization is observed in the Pd-modified filler metals when heated over ˜1100°C. As volatilization should be avoided, the ternary alloys should be limited to 15mol% Pd. It was found by sessile drop wetting experiments that there is a definitive change in wetting behavior that corresponds directly to the miscibility gap boundary for the Pd-Ag-CuO system. The first order transition tracks with changes in the miscibility gap boundary that can be induced by increasing palladium content. This is the first experimental evidence of critical point wetting behavior reported for a metal-oxide system and further confirms that critical point wetting theory is universal. Four-point bend testing and

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. VITRIFICATION OF MUNICIPAL SOLID WASTE COMBUSTION AIR POLLUTION CONTROL RESIDUES USING CORNING, INC. PROCESS

    EPA Science Inventory

    A demonstration was conducted to vitrify municipal solid waste (MSW) combustor air pollution control residue (APC) under the USEPA Municipal Waste Innovative Technology Evaluation Program. uplicate demonstration was conducted using a process developed by Corning Inc. in a cold cr...

  5. 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.

  6. 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.

  7. 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.

  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. PMID:25105268

  9. 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.

  10. 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.

  11. 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.

  12. Effects of the Fabrication Process and Thermal Cycling on the Oxidation of Zirconium-Niobium Pressure Tubes

    NASA Astrophysics Data System (ADS)

    Nam, Cheol

    2009-12-01

    Pressure tubes made of Zr-2.5%Nb alloy are used to contain fuels and coolant in CANDU nuclear power reactors The pressure tube oxidizes during reactor operation and hydrogen ingress through the oxide grown on the tube limits its lifetime. Little attention was paid to the intermediate tube manufacturing processes in enhancing the oxidation resistance. In addition, the oxide grown on the tube experiences various thermal cycles depending on the reactor shutdown and startup cycles. To address these two aspects and to better understand the oxidation process of the Zr-2.5Nb tube, research was conducted in two parts: (i) effects of tube fabrication on oxidation behavior, and (ii) thermal cycling behaviors of oxides grown on a pressure tube. In the first part, the optimum manufacturing process was pursued to improve the corrosion resistance of Zr-2.5Nb tubes. Experimental micro-tubes were fabricated with various manufacturing routes in the stages of billet preparation, hot extrusion and cold drawing. These were oxidized in air at 400°C and 500°C, and in an autoclave at 360°C lithiated water. Microstructure and texture of the tubes and oxides were characterized with X-ray diffraction, scanning electron microscope and optical microscope. Special emphasis was given to examinations of the metal/oxide interface structures. A correlation between the manufacturing process and oxidation resistance was investigated in terms of tube microstructure and the metal/oxide interface structure. As a result, it was consistently observed that uniform interface structures were formed on the tubes which had a fine distribution of secondary phases. These microstructures were found to be beneficial in enhancing the oxidation resistance as opposed to the tubes that had coarse and continuous beta-Zr phases. Based on these observations, a schematic model of the oxidation process was proposed with respect to the oxidation resistance under oxidizing temperatures of 360°C, 400°C and 500°C. In

  13. Nitrous oxide supersaturation at the liquid/air interface of animal waste.

    PubMed

    Makris, Konstantinos C; Andra, Syam S; Hardy, Michael; Sarkar, Dibyendu; Datta, Rupali; Bach, Stephan B H; Mullens, Conor P

    2009-12-01

    Concentrated animal feeding operations around the globe generate large amounts of nitrous oxide (N(2)O) in the surrounding atmosphere. Liquid animal waste systems have received little attention with respect to N(2)O emissions. We hypothesized that the solution chemistry of animal waste aqueous suspensions would promote conditions that lead to N(2)O supersaturation at the liquid/air interface. The concentration of dissolved N(2)O in poultry litter (PL) aqueous suspensions at 25 degrees C was 0.36 microg N(2)O mL(-1), at least an order of magnitude greater than that measured in water in equilibrium with ambient air, suggesting N(2)O supersaturation. There was a nonlinear increase in the N(2)O Henry constants of PL from 2810 atm/mole fraction at 35 degrees C to 17 300 atm/mole fraction at 41 degrees C. The extremely high N(2)O Henry constants were partially ascribed to N(2)O complexation with aromatic moieties. Complexed N(2)O structures were unstable at temperatures > 35 degrees C, supplying the headspace with additional free N(2)O concentrations. PMID:19573962

  14. 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

  15. 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. PMID:26259164

  16. 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

  17. 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

  18. Study of the effect of plasma-striking atmosphere on Fe-oxidation in thermal dc arc-plasma processing

    SciTech Connect

    Banerjee, I.; Khollam, Y. B.; Mahapatra, S. K.; Das, A. K.; Bhoraskar, S. V.

    2010-11-15

    The effect of plasma-striking atmosphere: air and air+Ar-gas on the crystallization of Fe-oxide phases was studied using dc thermal arc-plasma processing route. The powders were characterized by x-ray diffraction, vibrating sample magnetometry, transmission electron microscopy, and Moessbauer spectroscopy techniques. At room temperature and O{sub 2} rich atmosphere, arc-evaporated Fe{sup 2+} ions oxidize into either {gamma}-Fe{sub 2}O{sub 3} or Fe{sub 3}O{sub 4} depending upon the combining ratio of Fe with molecular O{sub 2}. Fe/O ratio could be adjusted using proper flow rate of Ar gas to crystallize the pure {gamma}-Fe{sub 2}O{sub 3}.

  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. 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

  1. 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.

  2. 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

  3. Applications of advanced oxidation processes: present and future.

    PubMed

    Suty, H; De Traversay, C; Cost, M

    2004-01-01

    The use of advanced oxidation processes (AOPs) to remove pollutants in various water treatment applications has been the subject of study for around 30 years. Most of the available processes (Fenton reagent, O3 under basic conditions, O3/H2O2, O3/UV, O3/solid catalyst, H2O2/M(n+), H2O2/UV, photo-assisted Fenton, H2O2/solid catalyst, H2O2/NaClO, TiO2/UV etc.) have been investigated in depth and a considerable body of knowledge has been built up about the reactivity of many pollutants. Various industrial applications have been developed, including ones for ground remediation (TCE, PCE), the removal of pesticides from drinking water, the removal of formaldehyde and phenol from industrial waste water and a reduction in COD from industrial waste water. The development of such AOP applications has been stimulated by increasingly stringent regulations, the pollution of water resources through agricultural and industrial activities and the requirement that industry meet effluent discharge standards. Nevertheless, it is difficult to obtain an accurate picture of the use of AOPs and its exact position in the range of water treatment processes has not been determined to date. The purpose of this overview is to discuss those processes and provide an indication of future trends. PMID:15077976

  4. 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%).

  5. 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.

  6. 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.

  7. Biomarkers of occupational exposure to air pollution, inflammation and oxidative damage in taxi drivers.

    PubMed

    Brucker, Natália; Moro, Angela M; Charão, Mariele F; Durgante, Juliano; Freitas, Fernando; Baierle, Marília; Nascimento, Sabrina; Gauer, Bruna; Bulcão, Rachel P; Bubols, Guilherme B; Ferrari, Pedro D; Thiesen, Flávia V; Gioda, Adriana; Duarte, Marta M M F; de Castro, Iran; Saldiva, Paulo H; Garcia, Solange C

    2013-10-01

    Exposure to environmental pollutants has been recognised as a risk factor for cardiovascular events. 1-hydroxypyrene (1-OHP) is a biomarker of exposure to polycyclic aromatic hydrocarbons (PAHs) from traffic-related air pollution. Experimental studies indicate that PAH exposure could be associated with inflammation and atherogenesis. Thus, the purpose of this study was to evaluate whether the biomarker of PAH exposure is associated with biomarkers of inflammation and oxidative stress and if these effects modulate the risk of developing cardiovascular diseases in workers exposed to air pollution. This study included 60 subjects, comprising 39 taxi drivers and 21 non-occupationally exposed persons. Environmental PM2.5 and benzo[a]pyrene (BaP) levels, in addition to biomarkers of exposure and oxidative damage, were determined. Inflammatory cytokines (IL-1β, IL-6, IL-10, TNF-α, IFN-γ and hs-CRP) and serum levels of oxidised LDL (ox-LDL), auto-antibodies (ox-LDL-Ab) and homocysteine (Hcy) were also evaluated. PM2.5 and BaP exhibited averages of 12.4±6.9 μg m(-3) and 1.0±0.6 ng m(-3), respectively. Urinary 1-OHP levels were increased in taxi drivers compared to the non-occupationally exposed subjects (p<0.05) and were positively correlated with pro-inflammatory cytokines and negatively correlated with antioxidants. Furthermore, taxi drivers had elevated pro-inflammatory cytokines, biomarkers of oxidative damage, and ox-LDL, ox-LDL-Ab and Hcy levels, although antioxidant enzymes were decreased compared to the non-occupationally exposed subjects (p<0.05). In summary, our findings indicate that taxi drivers showed major exposure to pollutants, such as PAHs, in relation to non-occupationally exposed subjects. This finding was associated with higher inflammatory biomarkers and Hcy, which represent important predictors for cardiovascular events. These data suggest a contribution of PAHs to cardiovascular diseases upon occupational exposure. PMID:23872245

  8. 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

  9. 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

  10. 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

  11. Long-Term Oxidation of Candidate Cast Iron and Advanced Austenitic Stainless Steel Exhaust System Alloys from 650-800 C in Air with Water Vapor

    DOE PAGESBeta

    Brady, Michael P; Muralidharan, Govindarajan; Leonard, Donovan N; Haynes, James A

    2014-01-01

    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 adherentmore » 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

  12. 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.

  13. Long-term oxidation of candidate cast iron and stainless steel exhaust system alloys from 650 to 800 °C in air with water vapor

    DOE PAGESBeta

    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

  14. 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.

  15. 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

  16. 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...

  17. 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…

  18. Poisoning and reactivation processes in oxide-type cathodes: Part I. Polycrystalline mixed oxides

    NASA Astrophysics Data System (ADS)

    Shih, A.; Haas, G. A.

    A study has been made of the poisoning and reactivation characteristics of alkaline earth oxide-type cathodes after extended periods of shelf storage. Both emitted and incident electrons were used to measure changes in the electronics properties, i.e. work function. The variations in work function over the surface were obtained in both distribution form as well as topographic presentation using a scanning low energy electron probe (SLEEP). These measurements were correlated with simultaneously occurring compositional changes using Auger, gas desorption and ion scattering techniques. Measurements were made on realistic cathodes in actual vacuum tube ambients. The results showed that oxide-type cathodes poison within a few hours after shut-down by the adsorption of residual gases contained in the vacuum ambient. (The effects of CO 2 were specifically demonstrated.) These adsorbates are, however, desorbed upon heating and in combination with other reactivation processes (such as formation of surface Ba layers when using reducing substrates), the cathode can reach full activation again by the time the temperature reaches the normal operating temperature. The poisoning and reactivation phenomena are a combination of a number of simultaneous processes, and studies to separate and identify these is the objective of part II of this paper.

  19. 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... an atmospheric chemistry perspective as well as from an environmental effects perspective,...

  20. 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.