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Sample records for air pure oxygen

  1. Aerobic and two-stage anaerobic-aerobic sludge digestion with pure oxygen and air aeration.

    PubMed

    Zupancic, Gregor D; Ros, Milenko

    2008-01-01

    The degradability of excess activated sludge from a wastewater treatment plant was studied. The objective was establishing the degree of degradation using either air or pure oxygen at different temperatures. Sludge treated with pure oxygen was degraded at temperatures from 22 degrees C to 50 degrees C while samples treated with air were degraded between 32 degrees C and 65 degrees C. Using air, sludge is efficiently degraded at 37 degrees C and at 50-55 degrees C. With oxygen, sludge was most effectively degraded at 38 degrees C or at 25-30 degrees C. Two-stage anaerobic-aerobic processes were studied. The first anaerobic stage was always operated for 5 days HRT, and the second stage involved aeration with pure oxygen and an HRT between 5 and 10 days. Under these conditions, there is 53.5% VSS removal and 55.4% COD degradation at 15 days HRT - 5 days anaerobic, 10 days aerobic. Sludge digested with pure oxygen at 25 degrees C in a batch reactor converted 48% of sludge total Kjeldahl nitrogen to nitrate. Addition of an aerobic stage with pure oxygen aeration to the anaerobic digestion enhances ammonium nitrogen removal. In a two-stage anaerobic-aerobic sludge digestion process within 8 days HRT of the aerobic stage, the removal of ammonium nitrogen was 85%. PMID:17251012

  2. Comparison of the macroscopic properties of field-accelerated electrons in dry air and in pure oxygen

    NASA Astrophysics Data System (ADS)

    Fournier, G.; Bonnet, J.; Pigache, D.

    1980-06-01

    The numerical solution of the Boltzmann equation for an ionized gas yields the macroscopic properties of electrons accelerated by an electric field in dry air and in pure oxygen. For the purpose of ozone generation, the stronger the field, the better the efficiency of oxygen dissociation. In air, the oxygen dissociation is found to be much less easy than that at the same amount of pure oxygen.

  3. Comparison of dissolved-organic-carbon residuals from air- and pure-oxygen-activated-sludge sequencing-batch reactors.

    PubMed

    Esparza-Soto, Mario; Fox, Peter; Westerhoff, Paul

    2006-03-01

    Literature shows that full-scale pure-oxygen activated sludge (O2-AS) wastewater treatment plants (WWTPs) generate effluents with higher dissolved-organic carbon (DOC) concentrations and larger high-molecular-weight fractions compared to air-activated-sludge (Air-AS) WWTP effluents. The purpose of this paper was to evaluate how gas supplied (air vs. pure oxygen) to sequencing-batch reactors affected DOC transformations. The main conclusions of this paper are (a) O2-AS effluent DOC is more refractory than air-AS effluent DOC; and (b) O2-AS systems may have higher five-day biochemical oxygen demand removals than air-AS systems; however, in terms of COD and DOC removal, air-AS systems are better than O2-AS systems. Analysis of a database from side-by-side O2- and air-AS pilot tests from literature supported these observations. PMID:16629273

  4. Scaling-up Fermentation of Pichia pastoris to demonstration-scale using new methanol-feeding strategy and increased air pressure instead of pure oxygen supplement

    PubMed Central

    Liu, Wan-Cang; Gong, Ting; Wang, Qing-Hua; Liang, Xiao; Chen, Jing-Jing; Zhu, Ping

    2016-01-01

    Scaling-up of high-cell-density fermentation (HCDF) of Pichia pastoris from the lab or pilot scale to the demonstration scale possesses great significance because the latter is the final technological hurdle in the decision to go commercial. However, related investigations have rarely been reported. In this paper, we study the scaling-up processes of a recombinant P. pastoris from the pilot (10 to 100-L) to the demonstration (1,000-L) scales, which can be used to convert 7-β-xylosyl-10-deacetyltaxol into 10-deacetyltaxol by the β-xylosidase for semi-synthesis of Taxol. We demonstrated that a pure oxygen supplement can be omitted from the HCDF if the super atmospheric pressure was increased from 0.05 to 0.10 ± 0.05 MPa, and we developed a new methanol feeding biomass-stat strategy (0.035 mL/g/h) with 1% dissolved oxygen and 100 g/L initial induction biomass (dry cell weight). The scaling-up was reproducible, and the best results were obtained from the 1,000-L scale, featuring a shorter induction time and the highest enzyme activities and productions, respectively. The specific growth and specific production rates were also determined. This study lays a solid foundation for the commercial preparation of 10-deacetyltaxol through the recombinant yeast. It also provides a successful paradigm for scaling-up HCDF of P. pastoris to the demonstration scale. PMID:26790977

  5. Laser ignition of bulk 1018 carbon steel in pure oxygen

    NASA Technical Reports Server (NTRS)

    Nguyen, K.; Branch, M. C.

    1986-01-01

    Experiments were undertaken to study the ignition characteristics of bulk 1018 carbon steel in a pure oxygen environment. Cylindrical 1018 carbon steel specimens 5 mm in diameter and 5 mm high were ignited by a focused CW CO2 laser beam in a cool, static, pure oxygen environment at oxygen pressures ranging from 0.103 to 6.895 MPa. A two-color pyrometer was designed and used to measure the ignition temperatures of the specimens. The temperature history of a spot approximately 0.5 mm in diameter located at the center of the specimen top surface was recorded with a maximum time resolution of 25 microsec, and with an accuracy of a few percent. Ignition temperature of bulk 1018 carbon steel was identified from the temperature history curve with the aid of the light intensity curve. Results show that 1018 carbon steel specimens ignite at temperatures between 1388 and 1450 K, which are below the melting range of the alloy (1662-1685 K). The ignition temperature of 1018 carbon steel is mildly dependent on oxygen pressure over the range of oxygen pressure investigated in this study.

  6. Pure Air`s Bailly scrubber: A four-year retrospective

    SciTech Connect

    Manavi, G.B.; Vymazal, D.C.; Sarkus, T.A.

    1997-12-31

    Pure Air`s Advanced Flue Gas Desulfurization (AFGD) Clean Coal Project has completed four highly successful years of operation at NIPSCO`s Bailly Station. As part of their program, Pure Air has concluded a six-part study of system performance. This paper summarizes the results of the demonstration program, including AFGD performance on coals ranging from 2.0--2.4% sulfur. The paper highlights novel aspects of the Bailly facility, including pulverized limestone injection, air rotary sparger for oxidation, wastewater evaporation system and the production of PowerChip{reg_sign} gypsum. Operations and maintenance which have led to the facility`s notable 99.47% availability record are also discussed. A project company, Pure Air on the Lake Limited Partnership, owns the AFGD facility. Pure Air was the turn key contractor and Air Products and Chemicals, Inc. is the operator of the AFGD system.

  7. Multiple pure tone elimination strut assembly. [air breathing engines

    NASA Technical Reports Server (NTRS)

    Burcham, F. W. (Inventor)

    1981-01-01

    An acoustic noise elimination assembly is disclosed which has a capability for disrupting the continuity of fields of sound pressures forwardly projected from fans or rotors of a type commonly found in the fan or compressor first stage for air-breathing engines, when operating at tip speeds in the supersonic range. The assembly includes a tubular cowl defining a duct for delivering an air stream axially into the intake for a jet engine. A sound barrier, defined by a number of intersecting flat plates or struts has a line of intersection coincident with a longitudinal axis of the tubular cowl, which serves to disrupt the continuity of rotating fields of multiple pure tonal components of noise.

  8. Water and Air Measures That Make 'PureSense'

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Each day, we read about mounting global concerns regarding the ability to sustain supplies of clean water and to reduce air contamination. With water and air serving as life s most vital elements, it is important to know when these environmental necessities may be contaminated, in order to eliminate exposure immediately. The ability to respond requires an understanding of the conditions impacting safety and quality, from source to tap for water, and from outdoor to indoor environments for air. Unfortunately, the "time-to-know" is not immediate with many current technologies, which is a major problem, given the greater likelihood of risky situations in today s world. Accelerating alert and response times requires new tools, methods, and technologies. New solutions are needed to engage in more rapid detection, analysis, and response. This is the focus of a company called PureSense Environmental, Inc., which evolved out of a unique relationship with NASA. The need for real-time management and operations over the quality of water and air, and the urgency to provide new solutions, were reinforced by the events of September 11, 2001. This, and subsequent events, exposed many of the vulnerabilities facing the multiple agencies tasked with working in tandem to protect communities from harmful disaster. Much has been done since September 11 to accelerate responses to environmental contamination. Partnerships were forged across the public and private sectors to explore, test, and use new tools. Methods and technologies were adopted to move more astutely from proof-of-concept to working solutions.

  9. A Cabin Air Separator for EVA Oxygen

    NASA Technical Reports Server (NTRS)

    Graf, John C.

    2011-01-01

    Presently, the Extra-Vehicular Activities (EVAs) conducted from the Quest Joint Airlock on the International Space Station use high pressure, high purity oxygen that is delivered to the Space Station by the Space Shuttle. When the Space Shuttle retires, a new method of delivering high pressure, high purity oxygen to the High Pressure Gas Tanks (HPGTs) is needed. One method is to use a cabin air separator to sweep oxygen from the cabin air, generate a low pressure/high purity oxygen stream, and compress the oxygen with a multistage mechanical compressor. A main advantage to this type of system is that the existing low pressure oxygen supply infrastructure can be used as the source of cabin oxygen. ISS has two water electrolysis systems that deliver low pressure oxygen to the cabin, as well as chlorate candles and compressed gas tanks on cargo vehicles. Each of these systems can feed low pressure oxygen into the cabin, and any low pressure oxygen source can be used as an on-board source of oxygen. Three different oxygen separator systems were evaluated, and a two stage Pressure Swing Adsorption system was selected for reasons of technical maturity. Two different compressor designs were subjected to long term testing, and the compressor with better life performance and more favorable oxygen safety characteristics was selected. These technologies have been used as the basis of a design for a flight system located in Equipment Lock, and taken to Preliminary Design Review level of maturity. This paper describes the Cabin Air Separator for EVA Oxygen (CASEO) concept, describes the separator and compressor technology trades, highlights key technology risks, and describes the flight hardware concept as presented at Preliminary Design Review (PDR)

  10. Pure-oxygen radiative shocks with electron thermal conduction

    NASA Technical Reports Server (NTRS)

    Borkowski, Kazimierz J.; Shull, J. Michael

    1990-01-01

    Steady state radiative shock models in gas composed entirely of oxygen are calculated with the purpose of explaining observations of fast-moving knots in Cas A and other oxygen-rich SNRs. Models with electron thermal conduction differ significantly from models in which conduction is neglected. Conduction reduces postshock electron temperatures by a factor of 7-10 and flattens temperature gradients. The O III ion, whose forbidden emission usually dominates the observed spectra, is present over a wide range of shock velocities, from 100 to 170 km/s. The electron temperature in the O III forbidden line formation region is 30,000 K, in agreement with the 20,000 K derived from observations. All models with conduction have extensive warm (T above 4000 K) photoionization zones, which provides better agreement with observed optical O I line strengths.

  11. Modelling of operation of a lithium-air battery with ambient air and oxygen-selective membrane

    NASA Astrophysics Data System (ADS)

    Sahapatsombut, Ukrit; Cheng, Hua; Scott, Keith

    2014-03-01

    A macro-homogeneous model has been developed to evaluate the impact of replacing pure oxygen with ambient air on the performance of a rechargeable non-aqueous Li-air battery. The model exhibits a significant reduction in discharge capacity, e.g. from 1240 to 226 mAh gcarbon-1 at 0.05 mA cm-2 when using ambient air rather than pure oxygen. The model correlates the relationship between the performance and electrolyte decomposition and formation of discharge products (such as Li2O2 and Li2CO3) under ambient air conditions. The model predicts a great benefit of using an oxygen-selective membrane on increasing capacity. The results indicate a good agreement between the experimental data and the model.

  12. Rechargeable aqueous lithium-air batteries with an auxiliary electrode for the oxygen evolution

    NASA Astrophysics Data System (ADS)

    Sunahiro, S.; Matsui, M.; Takeda, Y.; Yamamoto, O.; Imanishi, N.

    2014-09-01

    A rechargeable aqueous lithium-air cell with a third auxiliary electrode for the oxygen evolution reaction was developed. The cell consists of a lithium metal anode, a lithium conducting solid electrolyte of Li1+x+yAlx(Ti,Ge)2-xSiyP3-yO12, a carbon black oxygen reduction air electrode, a RuO2 oxygen evolution electrode, and a saturated aqueous solution of LiOH with 10 M LiCl. The cell was successfully operated for several cycles at 0.64 mA cm-2 and 25 °C under air, where the capacity of air electrode was 2000 mAh gcathod-1. The cell performance was degraded gradually by cycling under open air. The degradation was reduced under CO2-free air and pure oxygen. The specific energy density was calculated to be 810 Wh kg-1 from the weight of water, lithium, oxygen, and carbon in the air electrode.

  13. 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.

  14. Evaluation of the persistence of micropollutants through pure-oxygen activated sludge nitrification and denitrification

    USGS Publications Warehouse

    Levine, A.D.; Meyer, M.T.; Kish, G.

    2006-01-01

    The persistence of pharmaceuticals, hormones, and household and industrial chemicals through a pure-oxygen activated sludge, nitrification, denitrification wastewater treatment facility was evaluated. Of the 125 micropollutants that were tested in this study, 55 compounds were detected in the untreated wastewater, and 27 compounds were detected in the disinfected effluent. The persistent compounds included surfactants, fire-retardant chemicals, pesticides, fragrance compounds, hormones, and one pharmaceutical. Physical-chemical properties of micropollutants that affected partitioning onto wastewater solids included vapor pressure and octanol-water partition coefficients.

  15. PARALLEL EVALUATION OF AIR- AND OXYGEN-ACTIVATED SLUDGE

    EPA Science Inventory

    To provide data on the relative merits of air and oxygen in the activated sludge process, two 1900-cu m/day (0.5-mgd) activated sludge pilot plant, one air and one oxygen system, were operated side-by-side at the Joint Water Pollution Control Plant, Carson, California. Both of th...

  16. Oxygen separation from air using zirconia solid electrolyte membranes

    NASA Technical Reports Server (NTRS)

    Suitor, J. W.; Marner, W. J.; Schroeder, J. E.; Losey, R. W.; Ferrall, J. F.

    1988-01-01

    Air separation using a zirconia solid electrolyte membrane is a possible alternative source of oxygen. The process of zirconia oxygen separation is reviewed, and an oxygen plant concept using such separation is described. Potential cell designs, stack designs, and testing procedures are examined. Fabrication of the materials used in a zirconia module as well as distribution plate design and fabrication are examined.

  17. An oxygen enrichment attachment for use with humidified air

    PubMed Central

    Jebson, P.; Dewar, J.; White, J.

    1974-01-01

    Jebson, P., Dewar, J., and White, J. (1974).Thorax, 29, 371-376. An oxygen enrichment attachment for use with humidified air. An oxygen enrichment attachment is described which fulfils the basic requirements for intubated patients. Using values for tidal volume and inspiratory time found in the type of patients for whom the attachment is intended, a range of mean inspired oxygen concentration has been given for 2, 4, 6, 8, and 10 1/min oxygen flow. Images PMID:4850557

  18. Modification of pure oxygen absorption equipment for concurrent stripping of carbon dioxide

    USGS Publications Warehouse

    Watten, B.J.; Sibrell, P.L.; Montgomery, G.A.; Tsukuda, S.M.

    2004-01-01

    The high solubility of carbon dioxide precludes significant desorption within commercial oxygen absorption equipment. This operating characteristic of the equipment limits its application in recirculating water culture systems despite its ability to significantly increase allowable fish loading rates (kg/(L min)). Carbon dioxide (DC) is typically removed by air stripping. This process requires a significant energy input for forced air movement, air heating in cold climates and water pumping. We developed a modification for a spray tower that provides for carbon dioxide desorption as well as oxygen absorption. Elimination of the air-stripping step reduces pumping costs while allowing dissolved nitrogen to drop below saturation concentrations. This latter response provides for an improvement in oxygen absorption efficiency within the spray tower. DC desorption is achieved by directing head-space gases from the spray tower (O2, N2, CO2) through a sealed packed tower scrubber receiving a 2 N NaOH solution. Carbon dioxide is selectively removed from the gas stream, by chemical reaction, forming the product Na 2CO3. Scrubber off-gas, lean with regard to carbon dioxide but still rich with oxygen, is redirected through the spray tower for further stripping of DC and absorption of oxygen. Make-up NaOH is metered into the scrubbing solution sump on an as needed basis as directed by a feedback control loop programmed to maintain a scrubbing solution pH of 11.4-11.8. The spent NaOH solution is collected, then regenerated for reuse, in a batch process that requires relatively inexpensive hydrated lime (Ca(OH)2). A by-product of the regeneration step is an alkaline filter cake, which may have use in bio-solids stabilization. Given the enhanced gas transfer rates possible with chemical reaction, the required NaOH solution flow rate through the scrubber represents a fraction of the spray tower water flow rate. Further, isolation of the water being treated from the atmosphere (1

  19. Oxygen-enriched air for MHD power plants

    NASA Technical Reports Server (NTRS)

    Ebeling, R. W., Jr.; Cutting, J. C.; Burkhart, J. A.

    1979-01-01

    Cryogenic air-separation process cycle variations and compression schemes are examined. They are designed to minimize net system power required to supply pressurized, oxygen-enriched air to the combustor of an MHD power plant with a coal input of 2000 MWt. Power requirements and capital costs for oxygen production and enriched air compression for enrichment levels from 13 to 50% are determined. The results are presented as curves from which total compression power requirements can be estimated for any desired enrichment level at any delivery pressure. It is found that oxygen enrichment and recuperative heating of MHD combustor air to 1400 F yields near-term power plant efficiencies in excess of 45%. A minimum power compression system requires 167 MW to supply 330 lb of oxygen per second and costs roughly 100 million dollars. Preliminary studies show MHD/steam power plants to be competitive with plants using high-temperature air preheaters burning gas.

  20. Prediction of oxygen solubility in pure water and brines up to high temperatures and pressures

    NASA Astrophysics Data System (ADS)

    GENG, Ming; DUAN, Zhenhao

    2010-10-01

    A thermodynamic model is presented to calculate the oxygen solubility in pure water (273-600 K, 0-200 bar) and natural brines containing Na +, K +, Ca 2+, Mg 2+, Cl -, SO 42-, over a wide range of temperature, pressure and ionic strength with or close to experimental accuracy. This model is based on an accurate equation of state to calculate vapor phase chemical potential and a specific particle interaction model for liquid phase chemical potential. With this approach, the model can not only reproduce the existing experimental data, but also extrapolate beyond the data range from simple aqueous salt system to complicated brine systems including seawater. Compared with previous models, this model covers much wider temperature and pressure space in variable composition brine systems. A program for this model can be downloaded from the website: http://www.geochem-model.org.

  1. Voigt deconvolution method and its applications to pure oxygen absorption spectrum at 1270 nm band

    NASA Astrophysics Data System (ADS)

    AL-Jalali, Muhammad A.; Aljghami, Issam F.; Mahzia, Yahia M.

    2016-03-01

    Experimental spectral lines of pure oxygen at 1270 nm band were analyzed by Voigt deconvolution method. The method gave a total Voigt profile, which arises from two overlapping bands. Deconvolution of total Voigt profile leads to two Voigt profiles, the first as a result of O2 dimol at 1264 nm band envelope, and the second from O2 monomer at 1268 nm band envelope. In addition, Voigt profile itself is the convolution of Lorentzian and Gaussian distributions. Competition between thermal and collisional effects was clearly observed through competition between Gaussian and Lorentzian width for each band envelope. Voigt full width at half-maximum height (Voigt FWHM) for each line, and the width ratio between Lorentzian and Gaussian width (ΓLΓG- 1) have been investigated. The following applied pressures were at 1, 2, 3, 4, 5, and 8 bar, while the temperatures were at 298 K, 323 K, 348 K, and 373 K range.

  2. Voigt deconvolution method and its applications to pure oxygen absorption spectrum at 1270 nm band.

    PubMed

    Al-Jalali, Muhammad A; Aljghami, Issam F; Mahzia, Yahia M

    2016-03-15

    Experimental spectral lines of pure oxygen at 1270 nm band were analyzed by Voigt deconvolution method. The method gave a total Voigt profile, which arises from two overlapping bands. Deconvolution of total Voigt profile leads to two Voigt profiles, the first as a result of O2 dimol at 1264 nm band envelope, and the second from O2 monomer at 1268 nm band envelope. In addition, Voigt profile itself is the convolution of Lorentzian and Gaussian distributions. Competition between thermal and collisional effects was clearly observed through competition between Gaussian and Lorentzian width for each band envelope. Voigt full width at half-maximum height (Voigt FWHM) for each line, and the width ratio between Lorentzian and Gaussian width (ΓLΓG(-1)) have been investigated. The following applied pressures were at 1, 2, 3, 4, 5, and 8 bar, while the temperatures were at 298 K, 323 K, 348 K, and 373 K range. PMID:26709019

  3. The mechanism of oxygen isotopic fractionation during fungal denitrification - A pure culture study

    NASA Astrophysics Data System (ADS)

    Wrage-Moennig, Nicole; Rohe, Lena; Anderson, Traute-Heidi; Braker, Gesche; Flessa, Heinz; Giesemann, Annette; Lewicka-Szczebak, Dominika; Well, Reinhard

    2014-05-01

    Nitrous oxide (N2O) from soil denitrification originates from bacteria and - to an unknown extent - also from fungi. During fungal denitrification, oxygen (O) exchange takes place between H2O and intermediates of the denitrification process as in bacterial exchange[1,2]. However, information about enzymes involved in fungal O exchanges and the associated fractionation effects is lacking. The objectives of this study were to estimate the O fractionation and O exchange during the fungal denitrifying steps using a conceptual model[2] adapted from concepts for bacterial denitrification[3], implementing controls of O exchange proposed by Aerssens, et al.[4] and using fractionation models by Snider et al.[5] Six different pure fungal cultures (five Hypocreales, one Sordariales) known to be capable of denitrification were incubated under anaerobic conditions, either with nitrite or nitrate. Gas samples were analyzed for N2O concentration and its isotopic signatures (SP, average δ15N, δ18O). To investigate O exchange, both treatments were also established with 18O-labelled water as a tracer in the medium. The Hypocreales strains showed O exchange mainly at NO2- reductase (Nir) with NO2- as electron acceptor and no additional O exchange at NO3- reductase (Nar) with NO3- as electron acceptor. The only Hypocreales species having higher O exchange with NO3- than with NO2- also showed O exchange at Nar. The Sordariales species tested seems capable of O exchange at NO reductase (Nor) additionally to O exchange at Nir with NO2-. The data will help to better interpret stable isotope values of N2O from soils. .[1] D. M. Kool, N. Wrage, O. Oenema, J. Dolfing, J. W. Van Groenigen. Oxygen exchange between (de)nitrification intermediates and H2O and its implications for source determination of NO?3- and N2O: a review. Rapid Commun. Mass Spec. 2007, 21, 3569. [2] L. Rohe, T.-H. Anderson, B. Braker, H. Flessa, A. Giesemann, N. Wrage-Mönnig, R. Well. Fungal Oxygen Exchange between

  4. Oxygen Selective Membranes for Li-Air (O2) Batteries

    PubMed Central

    Crowther, Owen; Salomon, Mark

    2012-01-01

    Lithium-air (Li-air) batteries have a much higher theoretical energy density than conventional lithium batteries and other metal air batteries, so they are being developed for applications that require long life. Water vapor from air must be prevented from corroding the lithium (Li) metal negative electrode during discharge under ambient conditions, i.e., in humid air. One method of protecting the Li metal from corrosion is to use an oxygen selective membrane (OSM) that allows oxygen into the cell while stopping or slowing the ingress of water vapor. The desired properties and some potential materials for OSMs for Li-air batteries are discussed and the literature is reviewed. PMID:24958173

  5. Oxygen selective membranes for li-air (o2) batteries.

    PubMed

    Crowther, Owen; Salomon, Mark

    2012-01-01

    Lithium-air (Li-air) batteries have a much higher theoretical energy density than conventional lithium batteries and other metal air batteries, so they are being developed for applications that require long life. Water vapor from air must be prevented from corroding the lithium (Li) metal negative electrode during discharge under ambient conditions, i.e., in humid air. One method of protecting the Li metal from corrosion is to use an oxygen selective membrane (OSM) that allows oxygen into the cell while stopping or slowing the ingress of water vapor. The desired properties and some potential materials for OSMs for Li-air batteries are discussed and the literature is reviewed. PMID:24958173

  6. Performance and application of the Quantiflex air/oxygen mixer.

    PubMed

    Richardson, F J; Nunn, J F

    1976-11-01

    The Quantiflex air/oxygen mixer is designed to dispense mixtures of air and oxygen with separate controls for total gas flow rate and oxygen concentration of the mixture within the range 21-100%. A monitoring flowmeter is provided for the mixture and also, as a safety measure, for the oxygen component. This serves as an indicator that oxygen is flowing and also permits independent calculation of the oxygen concentration of the mixture. Delivered oxygen concentrations were found to be within +/- 2% of the indicated value at flow rates between 4 and 12 litre/min with the input pressures of either or both gases at 208-415 kPa (30-60 lbf/in2.) gauge, and with or without an output pressure of 20 kPa. At total flow rates of 1.5-2 litre/min there was a maximum discrepancy of 4% below and 8% above the indicated concentration in some delivered concentrations. Acceptability, ease, accuracy and quickness of use by nurses were compared with current methods using separate flowmeters for air and oxygen and calculating the required flow rates by means of arithmetic, graph and special-purpose slide-rule (Blease). The Quantiflex prototype was the most acceptable, the easiest, the most accurate and the fastest of the techniques investigated. PMID:136976

  7. Effects of fluoride and dissolved oxygen concentrations on the corrosion behavior of pure titanium and titanium alloys.

    PubMed

    Nakagawa, Masaharu; Matsuya, Shigeki; Udoh, Koichi

    2002-06-01

    The effects of dissolved-oxygen concentration and fluoride concentration on the corrosion behaviors of commercial pure titanium, Ti-6Al-4V and Ti-6Al-7Nb alloys and experimentally produced Ti-0.2Pd and Ti-0.5Pt alloys were examined using the corrosion potential measurements. The amount of dissolved Ti was analyzed by inductively coupled plasma mass spectroscopy. A decrease in the dissolved-oxygen concentration tended to reduce the corrosion resistance of Ti and Ti alloys. If there was no fluoride, however, corrosion did not occur. Under low dissolved-oxygen conditions, the corrosion of pure Ti and Ti-6Al-4V and Ti-6Al-7Nb alloys might easily take place in the presence of small amounts of fluoride. They were corroded by half or less of the fluoride concentrations in commercial dentifrices. The Ti-0.2Pd and Ti-0.5Pt alloys did not corrode more, even under the low dissolved-oxygen conditions and a fluoride-containing environment, than pure Ti and Ti-6Al-4V and Ti-6Al-7Nb alloys. These alloys are expected to be useful as new Ti alloys with high corrosion resistance in dental use. PMID:12238790

  8. Effect of combined recompression and air, oxygen, or heliox breathing on air bubbles in rat tissues.

    PubMed

    Hyldegaard, O; Kerem, D; Melamed, Y

    2001-05-01

    The fate of bubbles formed in tissues during the ascent from a real or simulated air dive and subjected to therapeutic recompression has only been indirectly inferred from theoretical modeling and clinical observations. We visually followed the resolution of micro air bubbles injected into adipose tissue, spinal white matter, muscle, and tendon of anesthetized rats recompressed to and held at 284 kPa while rats breathed air, oxygen, heliox 80:20, or heliox 50:50. The rats underwent a prolonged hyperbaric air exposure before bubble injection and recompression. In all tissues, bubbles disappeared faster during breathing of oxygen or heliox mixtures than during air breathing. In some of the experiments, oxygen breathing caused a transient growth of the bubbles. In spinal white matter, heliox 50:50 or oxygen breathing resulted in significantly faster bubble resolution than did heliox 80:20 breathing. In conclusion, air bubbles in lipid and aqueous tissues shrink and disappear faster during recompression during breathing of heliox mixtures or oxygen compared with air breathing. The clinical implication of these findings might be that heliox 50:50 is the mixture of choice for the treatment of decompression sickness. PMID:11299250

  9. Tracer study of oxygen and hydrogen uptake by Mg alloys in air with water vapor

    DOE PAGESBeta

    Brady, M. P.; Fayek, M.; Meyer, H. M.; Leonard, D. N.; Elsentriecy, H. H.; Unocic, K. A.; Anovitz, L. M.; Cakmak, E.; Keiser, J. R.; Song, G. L.; et al

    2015-05-15

    We studied the pure oxidation of Mg, Mg–3Al–1Zn (AZ31B), and Mg–1Zn–0.25Zr–<0.5Nd (ZE10A) at 85 °C in humid air using sequential exposures with H218O and D216O for water vapor. Incorporation of 18O in the hydroxide/oxide films indicated that oxygen from water vapor participated in the reaction. Moreover, penetration of hydrogen into the underlying metal was observed, particularly for the Zr- and Nd-containing ZE10A. Isotopic tracer profiles suggested a complex mixed inward/outward film growth mechanism.

  10. Hybrid membrane--PSA system for separating oxygen from air

    DOEpatents

    Staiger, Chad L.; Vaughn, Mark R.; Miller, A. Keith; Cornelius, Christopher J.

    2011-01-25

    A portable, non-cryogenic, oxygen generation system capable of delivering oxygen gas at purities greater than 98% and flow rates of 15 L/min or more is described. The system consists of two major components. The first component is a high efficiency membrane capable of separating argon and a portion of the nitrogen content from air, yielding an oxygen-enriched permeate flow. This is then fed to the second component, a pressure swing adsorption (PSA) unit utilizing a commercially available, but specifically formulated zeolite compound to remove the remainder of the nitrogen from the flow. The system is a unique gas separation system that can operate at ambient temperatures, for producing high purity oxygen for various applications (medical, refining, chemical production, enhanced combustion, fuel cells, etc . . . ) and represents a significant advance compared to current technologies.

  11. Fuel Cells Utilizing Oxygen From Air at Low Pressures

    NASA Technical Reports Server (NTRS)

    Cisar, Alan; Boyer, Chris; Greenwald, Charles

    2006-01-01

    A fuel cell stack has been developed to supply power for a high-altitude aircraft with a minimum of air handling. The fuel cell is capable of utilizing oxygen from ambient air at low pressure with no need for compression. For such an application, it is advantageous to take oxygen from the air (in contradistinction to carrying a supply of oxygen onboard), but it is a challenging problem to design a fuel-cell stack of reasonable weight that can generate sufficient power while operating at reduced pressures. The present fuel-cell design is a response to this challenge. The design features a novel bipolar plate structure in combination with a gas-diffusion structure based on a conductive metal core and a carbon gas-diffusion matrix. This combination makes it possible for the flow fields in the stack to have a large open fraction (ratio between open volume and total volume) to permit large volumes of air to flow through with exceptionally low backpressure. Operations at reduced pressure require a corresponding increase in the volume of air that must be handled to deliver the same number of moles of oxygen to the anodes. Moreover, the increase in the open fraction, relative to that of a comparable prior fuel-cell design, reduces the mass of the stack. The fuel cell has been demonstrated to operate at a power density as high as 105 W/cm2 at an air pressure as low as 2 psia (absolute pressure 14 kPa), which is the atmospheric pressure at an altitude of about 50,000 ft ( 15.2 km). The improvements in the design of this fuel cell could be incorporated into designs of other fuel cells to make them lighter in weight and effective at altitudes higher than those of prior designs. Potential commercial applications for these improvements include most applications now under consideration for fuel cells.

  12. Sooting Limits Of Diffusion Flames With Oxygen-Enriched Air And Diluted Fuel

    NASA Technical Reports Server (NTRS)

    Sunderland, P. B.; Urban, D. L.; Stocker, D. P.; Chao, B. H.; Axelbaum, R. L.

    2003-01-01

    Oxygen-enhanced combustion permits certain benefits and flexibility that are not otherwise available in the design of practical combustors, as discussed by Baukal. The cost of pure and enriched oxygen has declined to the point that oxygen-enhanced combustion is preferable to combustion in air for many applications. Carbon sequestration is greatly facilitated by oxygen enrichment because nitrogen can be eliminated from the product stream. For example, when natural gas (or natural gas diluted with CO2) is burned in pure oxygen, the only significant products are water and CO2. Oxygen-enhanced combustion also has important implications for soot formation, as explored in this work. We propose that soot inception in nonpremixed flames requires a region where C/O ratio, temperature, and residence time are above certain critical values. Soot does not form at low temperatures, with the threshold in nonpremixed flames ranging from about 1250-1650 K, a temperature referred to here as the critical temperature for soot inception, Tc. Soot inception also can be suppressed when residence time is short (equivalently, when the strain rate in counterflow flames is high). Soot induction times of 0.8-15 ms were reported by Tesner and Shurupov for acetylene/nitrogen mixtures at 1473 K. Burner stabilized spherical microgravity flames are employed in this work for two main reasons. First, this configuration offers unrestricted control over convection direction. Second, in steady state these flames are strain-free and thus can yield intrinsic sooting limits in diffusion flames, similar to the way past work in premixed flames has provided intrinsic values of C/O ratio associated with soot inception limits.

  13. Presence of organophosphorus pesticide oxygen analogs in air samples

    PubMed Central

    Armstrong, Jenna L.; Fenske, Richard A.; Yost, Michael G.; Galvin, Kit; Tchong-French, Maria; Yu, Jianbo

    2012-01-01

    A number of recent toxicity studies have highlighted the increased potency of oxygen analogs (oxons) of several organophosphorus (OP) pesticides. These findings were a major concern after environmental oxons were identified in environmental samples from air and surfaces following agricultural spray applications in California and Washington State. This paper reports on the validity of oxygen analog measurements in air samples for the OP pesticide, chlorpyrifos. Controlled environmental and laboratory experiments were used to examine artificial formation of chlorpyrifos-oxon using OSHA Versatile Sampling (OVS) tubes as recommended by NIOSH method 5600. Additionally, we compared expected chlorpyrifos-oxon attributable to artificial transformation to observed chlorpyrifos-oxon in field samples from a 2008 Washington State Department of Health air monitoring study using non-parametric statistical methods. The amount of artificially transformed oxon was then modeled to determine the amount of oxon present in the environment. Toxicity equivalency factors (TEFs) for chlorpyrifos-oxon were used to calculate chlorpyrifos-equivalent air concentrations. The results demonstrate that the NIOSH-recommended sampling matrix (OVS tubes with XAD-2 resin) was found to artificially transform up to 30% of chlorpyrifos to chlorpyrifos-oxon, with higher percentages at lower concentrations (< 30 ng/m3) typical of ambient or residential levels. Overall, the 2008 study data had significantly greater oxon than expected by artificial transformation, but the exact amount of environmental oxon in air remains difficult to quantify with the current sampling method. Failure to conduct laboratory analysis for chlorpyrifos-oxon may result in underestimation of total pesticide concentration when using XAD-2 resin matrices for occupational or residential sampling. Alternative methods that can accurately measure both OP pesticides and their oxygen analogs should be used for air sampling, and a toxicity

  14. Presence of organophosphorus pesticide oxygen analogs in air samples

    NASA Astrophysics Data System (ADS)

    Armstrong, Jenna L.; Fenske, Richard A.; Yost, Michael G.; Galvin, Kit; Tchong-French, Maria; Yu, Jianbo

    2013-02-01

    A number of recent toxicity studies have highlighted the increased potency of oxygen analogs (oxons) of several organophosphorus (OP) pesticides. These findings were a major concern after environmental oxons were identified in environmental samples from air and surfaces following agricultural spray applications in California and Washington State. This paper reports on the validity of oxygen analog measurements in air samples for the OP pesticide, chlorpyrifos. Controlled environmental and laboratory experiments were used to examine artificial formation of chlorpyrifos-oxon using OSHA Versatile Sampling (OVS) tubes as recommended by NIOSH method 5600. Additionally, we compared expected chlorpyrifos-oxon attributable to artificial transformation to observed chlorpyrifos-oxon in field samples from a 2008 Washington State Department of Health air monitoring study using non-parametric statistical methods. The amount of artificially transformed oxon was then modeled to determine the amount of oxon present in the environment. Toxicity equivalency factors (TEFs) for chlorpyrifos-oxon were used to calculate chlorpyrifos-equivalent air concentrations. The results demonstrate that the NIOSH-recommended sampling matrix (OVS tubes with XAD-2 resin) was found to artificially transform up to 30% of chlorpyrifos to chlorpyrifos-oxon, with higher percentages at lower concentrations (<30 ng m-3) typical of ambient or residential levels. Overall, the 2008 study data had significantly greater oxon than expected by artificial transformation, but the exact amount of environmental oxon in air remains difficult to quantify with the current sampling method. Failure to conduct laboratory analysis for chlorpyrifos-oxon may result in underestimation of total pesticide concentration when using XAD-2 resin matrices for occupational or residential sampling. Alternative methods that can accurately measure both OP pesticides and their oxygen analogs should be used for air sampling, and a toxicity

  15. Can an oxygenator design potentially contribute to air embolism in cardiopulmonary bypass? A novel method for the determination of the air removal capabilities of neonatal membrane oxygenators.

    PubMed

    De Somer, F; Dierickx, P; Dujardin, D; Verdonck, P; Van Nooten, G

    1998-05-01

    At present, air handling of a membrane oxygenator is generally studied by using an ultrasonic sound bubble counter. However, this is not a quantitative method and it does not give any information on where air was entrapped in the oxygenator and if it eventually was removed through the membrane for gas exchange. The study presented here gives a novel technique for the determination of the air-handling characteristics of a membrane oxygenator. The study aimed at defining not only the amount of air released by the oxygenator, but also the amount of air trapped within the oxygenator and/or removed through the gas exchange membrane. Two neonatal membrane oxygenators without the use of an arterial filter were investigated: the Polystan Microsafe and the Dideco Lilliput. Although the air trap function of both oxygenators when challenged with a bolus of air was similar, the Microsafe obtained this effect mainly by capturing the air in the heat exchanger compartment while the Lilliput did remove a large amount of air through the membrane. In conclusion, the difference in trap function was most striking during continuous infusion of air. Immediate contact with a microporous membrane, avoidance of high velocities within the oxygenator, pressure drop, transit time and construction of the fibre mat all contribute to the air-handling characteristics of a membrane oxygenator. PMID:9638712

  16. Structural and electrical properties of pure and Cu doped NiO films deposited at various oxygen partial pressures

    NASA Astrophysics Data System (ADS)

    Reddy, Y. Ashok Kumar; Reddy, A. Mallikarjuna; Reddy, A. Sivasankar; Reddy, P. Sreedhara

    2013-02-01

    Pure and Cu doped NiO thin films were successfully deposited by dc reactive magnetron sputtering technique at various oxygen partial pressures in the range 9 × 10-5 to 6 × 10-4 mbar. It was observed that oxygen partial pressure influence the structural and electrical properties. All the deposited films were polycrystalline and exhibited cubic structure with preferential growth along (220) plane for NiO films and (111) and (220) planes for Cu doped NiO films. All the deposited films exhibited p-type conductivity. The electrical resistivity decreased from 62.24 to 9.94 Ω cm and the mobility and carrier concentration were increased with oxygen partial pressure.

  17. Raman spectroscopy analysis of air grown oxide scale developed on pure zirconium substrate

    NASA Astrophysics Data System (ADS)

    Kurpaska, L.; Favergeon, J.; Lahoche, L.; El-Marssi, M.; Grosseau Poussard, J.-L.; Moulin, G.; Roelandt, J.-M.

    2015-11-01

    Using Raman spectroscopy technique, external and internal parts of zirconia oxide films developed at 500 °C and 600 °C on pure zirconium substrate under air at normal atmospheric pressure have been examined. Comparison of Raman peak positions of tetragonal and monoclinic zirconia phases, recorded during the oxide growth at elevated temperature, and after cooling at room temperature have been presented. Subsequently, Raman peak positions (or shifts) were interpreted in relation with the stress evolution in the growing zirconia scale, especially closed to the metal/oxide interface, where the influence of compressive stress in the oxide is the biggest. Reported results, for the first time show the presence of a continuous layer of tetragonal zirconia phase developed in the proximity of pure zirconium substrate. Based on the Raman peak positions we prove that this tetragonal layer is stabilized by the high compressive stress and sub-stoichiometry level. Presence of the tetragonal phase located in the outer part of the scale have been confirmed, yet its Raman characteristics suggest a stress-free tetragonal phase, therefore different type of stabilization mechanism. Presented study suggest that its stabilization could be related to the lattice defects introduced by highstoichiometry of zirconia or presence of heterovalent cations.

  18. Ab-initio study of oxygen defects in pure ThO2

    NASA Astrophysics Data System (ADS)

    Ghosh, Partha S.; Gupta, S. K.; Ali, K.; Arya, A.; Dey, G. K.

    2016-05-01

    First principles calculations using projector augmented wave potentials and generalized gradient approximations predicts the structural relaxations due to neutral and positively charged oxygen defects (+1 and +2) in bulk thoria leads to symmetric distortion around the vacancy site. Electronic Density of states (DOS) analysis shows presence of defects states mainly contributed by Th d and f states near the conduction band minima for the double positively charged oxygen vacancy which is having lowest energy of formation.

  19. Near-infrared spectroscopic assessment of oxygen delivery to free flaps on monkeys following vascular occlusions and inhalation of pure oxygen

    NASA Astrophysics Data System (ADS)

    Tian, Fenghua; Ding, Haishu; Cai, Zhigang; Wang, Guangzhi; Zhao, Fuyun

    2002-04-01

    In recent studies, near-infrared spectroscopy (NIRS) has been considered as a potentially ideal noninvasive technique for the postoperative monitoring of plastic surgery. In this study, free flaps were raised on rhesus monkeys' forearms and oxygen delivery to these flaps was monitored following vascular occlusions and inhalation of pure oxygen. Optical fibers were adopted in the probe of the oximeter so that the detection could be performed in reflectance mode. The distance between emitter and detector can be adjusted easily to achieve the best efficacy. Different and repeatable patterns of changes were measured following vascular occlusions (arterial occlusion, venous occlusion and total occlusion) on flaps. It is clear that the near-infrared spectroscopy is capable of postoperatively monitoring vascular problems in flaps. NIRS showed high sensitivity to detect the dynamic changes in flaps induced by inhalation of pure oxygen in this study. The experimental results indicated that it was potential to assess tissue viability utilizing the dynamic changes induced by a noninvasive stimulation. It may be a new assessing method that is rapid, little influenced by other factors and brings less discomfort to patients.

  20. The balance model of oxygen enrichment of atmospheric air

    NASA Astrophysics Data System (ADS)

    Popov, Alexander

    2013-04-01

    The study of turnover of carbon and oxygen is an important line of scientific investigation. This line takes on special significance in conditions of soil degradation, which leads to the excess content of carbon dioxide and, as result, decrease of oxygen in the atmosphere. The aim of this article is a statement the balance model of oxygen enrichment of atmospheric air (ratio O/C) depending on consumption and assimilation by plants of dissolved organic matter (DOM) and the value of the oxidation-reduction potential (Eh). Basis of model was the following: green vascular plants are facultative heterotrophic organisms with symbiotic digestion and nutrition. According to the trophology viewpoint, the plant consumption of organic compounds broadens greatly a notion about the plant nutrition and ways of its regulation. In particular, beside the main known cycle of carbon: plant - litter - humus - carbon dioxide - plant, there is the second carbon cycle (turnover of organic compounds): plant - litter - humus - DOM - plant. The biogeochemical meaning of consumption of organic compounds by plants is that plants build the structural and functional blocks of biological macromolecules in their bodies. It provides receiving of a certain "energy payoff" by plants, which leads to increase of plant biomass by both an inclusion of allochthonous organic molecules in plant tissues, and positive effect of organic compounds on plant metabolic processes. One more of powerful ecological consequence of a heterotrophic nutrition of green plants is oxygen enrichment of atmospheric air. As the organic molecules in the second biological cycle of carbon are built in plants without considerable chemical change, the atmospheric air is enriched on that amount of oxygen, which would be required on oxidation of the organic molecules absorbed by plants, in result. It was accepted that: plant-soil system was climax, the plant community was grassy, initial contents of carbon in phytomass was accepted

  1. Variable oxygen/nitrogen enriched intake air system for internal combustion engine applications

    DOEpatents

    Poola, Ramesh B.; Sekar, Ramanujam R.; Cole, Roger L.

    1997-01-01

    An air supply control system for selectively supplying ambient air, oxygen enriched air and nitrogen enriched air to an intake of an internal combustion engine includes an air mixing chamber that is in fluid communication with the air intake. At least a portion of the ambient air flowing to the mixing chamber is selectively diverted through a secondary path that includes a selectively permeable air separating membrane device due a differential pressure established across the air separating membrane. The permeable membrane device separates a portion of the nitrogen in the ambient air so that oxygen enriched air (permeate) and nitrogen enriched air (retentate) are produced. The oxygen enriched air and the nitrogen enriched air can be selectively supplied to the mixing chamber or expelled to atmosphere. Alternatively, a portion of the nitrogen enriched air can be supplied through another control valve to a monatomic-nitrogen plasma generator device so that atomic nitrogen produced from the nitrogen enriched air can be then injected into the exhaust of the engine. The oxygen enriched air or the nitrogen enriched air becomes mixed with the ambient air in the mixing chamber and then the mixed air is supplied to the intake of the engine. As a result, the air being supplied to the intake of the engine can be regulated with respect to the concentration of oxygen and/or nitrogen.

  2. Ambient air measurements of monoterpenes, oxygenated terpenes, and sesquiterpenes

    NASA Astrophysics Data System (ADS)

    Bouvier-Brown, N. C.; Goldstein, A. H.

    2007-12-01

    Chemical ozone loss within the forest canopy and the presence of biogenic VOC (BVOC) oxidation products in and above the canopy indirectly suggest the presence of very reactive BVOCs at Blodgett Forest. As a part of the 2007 BEARPEX campaign at this coniferous forest in the Sierra Nevada Mountains of California (1300 m elevation, 38.90° N, 120.63° W,), we quantified ambient concentrations of terpenes using a modified in-situ gas chromatograph with a mass spectrometer and a flame ionization detector (GC-MS-FID). The range of terpenes observed in ambient air matched enclosure based measurements of branch level emissions. To our knowledge, these observations represent the first quantification of the oxygenated monoterpene methyl chavicol and various sesquiterpenes in ambient air. Details of the instrument modifications, diurnal profiles of the terpenes, and comparison to branch level emissions will be presented.

  3. Potentiating Effect of Pure Oxygen on the Enhancement of Respiration by Ethylene in Plant Storage Organs: A Comparative Study 1

    PubMed Central

    Theologis, Athanasios; Laties, George G.

    1982-01-01

    A number of fruits and bulky storage organs were studied with respect to the effect of pure O2 on the extent and time-course of the respiratory rise induced by ethylene. In one group, of which potato (Solanum tuberosum var. Russet) and carrot (Daucus carota) are examples, the response to ethylene in O2 is much greater than in air. In a second group, of which avocado (Persea americana Mill. var. Hass) and banana (Musa cavendishii Lambert var. Valery) are examples, air and O2 are equally effective. When O2-responsive organs are peeled, air and O2 synergize the ethylene response to the same extent in parsnip (Pastinaca sativa), whereas O2 is more stimulatory than air in carrots. In the latter instance, carrot flesh is considered to contribute significantly to diffusion resistance. The release of CO2, an ethylene antagonist, is recognized as another element in the response to peeling. The potentiating effect of O2 is considered to be primarily on ethylene action in the development of the respiratory rise rather than on the respiration process per se. On the assumption that diffusion controls O2 movement into bulky organs and the peel represents the major diffusion barrier, simple calculations indicate that the O2 concentration in untreated organs in air readily sustains respiration. Furthermore, in ethylene-treated organs in pure O2, the internal O2 concentration is more than enough to maintain the high respiration rates. Skin conductivity to O2 is the fundamental parameter differentiating O2-responsive from O2-nonresponsive fruits and bulky storage organs. The large preceding the earliest response to ethylene, as well as the magnitude of the ethylene-induced respiratory rise, is also controlled by permeability characteristics of the peel. PMID:16662339

  4. Effect of air, heliox, and oxygen breathing on air bubbles in aqueous tissues in the rat.

    PubMed

    Hyldegaard, O; Madsen, J

    1994-12-01

    Our purpose was to examine the behavior of air bubbles in three non-lipid tissues (skeletal muscle, tendon, and the anterior chamber of the eye) during breathing of air, helium-oxygen (heliox, 80:20), or oxygen. Air bubbles were injected into skeletal muscle or tendon in rats after decompression from a 1-h air exposure at 3.5 atm abs (355 kPa) or into the anterior chamber of the rat eye without any previous pressure exposure. The bubbles were studied by photomicroscopy at 1 atm abs (101 kPa) during either air breathing or during air breathing followed by heliox or O2 breathing. Muscle: during air breathing, all bubbles initially increased in size for a period of 55-100 min after decompression and then started to shrink. Both heliox and O2 breathing increased the shrinking rate as compared to air. Bubble size decreased more rapidly during O2 than heliox breathing. Tendon: during air breathing, bubble size decreased at a constant rate; in one bubble the decrease was preceded by a small increase. During heliox breathing most bubbles decreased faster than during breathing of air. O2 breathing caused a short-term increase in bubble size in 4 out of 10 bubbles. Otherwise, the shrinkage rate was increased in six bubbles and uninfluenced in four bubbles during breathing of O2. Rat eye: during air breathing all bubbles shrank in the observation period. When heliox breathing was started, all bubbles transiently grew for 10-35 min, after which they began shrinking faster than during air breathing. When O2 breathing was started, five out of seven bubbles initially grew or stopped shrinking for 5-15 min, after which they decreased in size faster than during both air and heliox breathing. We conclude that breathing of either heliox or O2 will cause air bubbles in aqueous tissues to disappear faster than during breathing of air. Since heliox breathing promoted bubble shrinking in both muscle and tendon, gas exchange was probably not primarily limited by extravascular diffusion in

  5. Fire-air and dephlogistication. Revisionisms of oxygen's discovery.

    PubMed

    Severinghaus, John W

    2003-01-01

    Americans are taught that Joseph Priestley discovered oxygen in 1774 and promptly brought that news to Lavoisier. Lavoisier proved that air contained a new element, oxygen, which combined with hydrogen to make water. He disproved the phlogiston theory but Priestley called it dephlogisticated air until his death 30 years later. Scandanavians learn that a Swedish apothecary Carl Wilhelm Scheele beat Priestley by 2 years but was deprived of credit because Lavoisier denied receiving a letter Scheele later claimed to have sent in September 1774 describing his 1772 discovery of "fire air". His claim was unconfirmed because Scheele first published his work in 1777. However, Scheele's missing letter was made public in 1992 in Paris, 218 years late, and now resides at the French Academie de Sciences. Lavoisier received it on Oct 15, 1774. His guilt was kept secret in the effects of Madame Lavoisier. He failed on several occasions to credit either Priestley or Scheele for contributing to the most important discovery in the history of science. Priestley was a teacher, political philosopher, essayist, Unitarian minister and pioneer in chemical and electrical science. He discovered 9 gases including nitrous oxide. He invented soda water, refrigeration, and gum erasers for which he coined the term "rubber". He discovered photosynthesis. He was humorless, argumentative, brilliant and passionate, called a "furious free-thinker". While his liberal colleagues Josiah Wedgwood, Erasmus Darwin, James Watts, and others of the Lunar Society were celebrating the 2nd anniversary of the French revolution, a Birmingham mob, supported by the royalists and the established church, destroyed Priestley's home, laboratory and church. Driven from England, he emigrated to Pennsylvania where he built a home and laboratory and collected a 1600 volume library, then among the largest in America. He is regarded as a founder of liberal Unitarian thinking. He was friend and correspondent of Thomas

  6. Increase in whole-body peripheral vascular resistance during three hours of air or oxygen prebreathing

    NASA Technical Reports Server (NTRS)

    Waligora, J. M.; Horrigan, D. J., Jr.; Conkin, J.; Dierlam, J. J.; Stanford, J., Jr.; Riddle, J. R.

    1984-01-01

    Male and female subjects prebreathed air or 100% oxygen through a mask for 3.0 hours while comfortably reclined. Blood pressures, heart rate, and cardiac output were collected before and after the prebreathe. Peripheral vascular resistance (PVR) was calculated from these parameters and increased by 29% during oxygen prebreathing and 15% during air prebreathing. The oxygen contributed substantially to the increase in PVR. Diastolic blood pressure increased by 18% during the oxygen prebreathe while stystolic blood pressure showed no change under either procedure. The increase in PVR during air prebreathing was attributed to procedural stress common to air and oxygen prebreathing.

  7. Tracer study of oxygen and hydrogen uptake by Mg alloys in air with water vapor

    SciTech Connect

    Brady, M. P.; Fayek, M.; Meyer, H. M.; Leonard, D. N.; Elsentriecy, H. H.; Unocic, K. A.; Anovitz, L. M.; Cakmak, E.; Keiser, J. R.; Song, G. L.; Davis, B.

    2015-05-15

    We studied the pure oxidation of Mg, Mg–3Al–1Zn (AZ31B), and Mg–1Zn–0.25Zr–<0.5Nd (ZE10A) at 85 °C in humid air using sequential exposures with H218O and D216O for water vapor. Incorporation of 18O in the hydroxide/oxide films indicated that oxygen from water vapor participated in the reaction. Moreover, penetration of hydrogen into the underlying metal was observed, particularly for the Zr- and Nd-containing ZE10A. Isotopic tracer profiles suggested a complex mixed inward/outward film growth mechanism.

  8. Arteriolar oxygenation in tumour and subcutaneous arterioles: effects of inspired air oxygen content.

    PubMed Central

    Dewhirst, M. W.; Ong, E. T.; Rosner, G. L.; Rehmus, S. W.; Shan, S.; Braun, R. D.; Brizel, D. M.; Secomb, T. W.

    1996-01-01

    Carbogen is thought to be more effective than normobaric oxygen in reducing tumour hypoxia because it may reduce hyperoxic vasoconstriction. In this study, tumour and normal arteriolar diameters were measured simultaneously with perivascular pO2 during air breathing followed by either carbogen or 100% oxygen to determine whether the action of carbogen is the result of alterations in feeding vessel diameter. Fischer-344 rats bearing dorsal flap window chambers, with or without implanted R3230AC tumours, were the experimental subjects. Arteriolar diameters were measured using optical techniques and perivascular pO2 was measured using recessed-tip electrodes (3-6 microns tip diameter). Baseline arteriolar pO2 averaged 30-50% of blood gas pO2 (mean = 97 mmHg). Both hyperoxic gases increased blood gas pO2 by 4-to 5-fold, but relative improvements in arteriolar pO2 were < or = 2.5 for all arterioles studied. This means that these normobaric high O2 gases are not very efficient in increasing O2 delivery to tumours. In addition, improvements in tumour arteriolar pO2 were transient for both hyperoxic gases. Oxygen and carbogen caused no change and mild vasodilatory responses in tumour arterioles, respectively. Normal arterioles on the other hand, tended toward vasoconstriction by carbogen breathing. Peri-arteriolar pO2 in tumours increased within the first 5 min of breathing either hyperoxic gas, followed by a decline back toward values seen with air-breathing. These results suggest that temporal changes in tumour oxygenation after exposure to carbogen or O2 may not be due to changes in perfusion. Other factors, such as changes in O2 consumption rate may be involved. PMID:8763889

  9. Improving Settling Characteristics of Pure Oxygen Activated Sludge by Stripping of Carbon Dioxide.

    PubMed

    Kundral, Somshekhar; Mudragada, Ratnaji; Coro, Ernesto; Moncholi, Manny; Mora, Nelson; Laha, Shonali; Tansel, Berrin

    2015-06-01

    Increased microbial activity at high ambient temperatures can be problematic for secondary clarifiers and gravity concentrators due to carbon dioxide (CO2) production. Production of CO2 in gravity concentrators leads to septic conditions and poor solids separation. The CO2 production can also be corrosive for the concrete surfaces. Effectiveness of CO2 stripping to improve solids settling was investigated using the sludge volume index (SVI) as the indicator parameter. Carbon dioxide was stripped by aeration from the sludge samples. Results from the study show that aeration also increased the pH values in the mixed liquor while removing CO2 and improving sludge settling. After 10 minutes of aeration at a rate of 0.37 m3 air/m3 water/min, 90% CO2 stripping was achieved. Based on the 30 min settling tests, the SVI increased by 26±1% after CO2 stripping while the pH increased by 0.8±0.1 pH units. PMID:26459818

  10. The Pathway for Oxygen: Tutorial Modelling on Oxygen Transport from Air to Mitochondrion: The Pathway for Oxygen.

    PubMed

    Bassingthwaighte, James B; Raymond, Gary M; Dash, Ranjan K; Beard, Daniel A; Nolan, Margaret

    2016-01-01

    The 'Pathway for Oxygen' is captured in a set of models describing quantitative relationships between fluxes and driving forces for the flux of oxygen from the external air source to the mitochondrial sink at cytochrome oxidase. The intervening processes involve convection, membrane permeation, diffusion of free and heme-bound O2 and enzymatic reactions. While this system's basic elements are simple: ventilation, alveolar gas exchange with blood, circulation of the blood, perfusion of an organ, uptake by tissue, and consumption by chemical reaction, integration of these pieces quickly becomes complex. This complexity led us to construct a tutorial on the ideas and principles; these first PathwayO2 models are simple but quantitative and cover: (1) a 'one-alveolus lung' with airway resistance, lung volume compliance, (2) bidirectional transport of solute gasses like O2 and CO2, (3) gas exchange between alveolar air and lung capillary blood, (4) gas solubility in blood, and circulation of blood through the capillary syncytium and back to the lung, and (5) blood-tissue gas exchange in capillaries. These open-source models are at Physiome.org and provide background for the many respiratory models there. PMID:26782201

  11. Durability of Membrane Electrode Assemblies (MEAs) in PEM Fuel Cells Operated on Pure Hydrogen and Oxygen

    NASA Technical Reports Server (NTRS)

    Stanic, Vesna; Braun, James; Hoberecht, Mark

    2003-01-01

    Proton exchange membrane (PEM) fuel cells are energy sources that have the potential to replace alkaline fuel cells for space programs. Broad power ranges, high peak-to-nominal power capabilities, low maintenance costs, and the promise of increased life are the major advantages of PEM technology in comparison to alkaline technology. The probability of PEM fuel cells replacing alkaline fuel cells for space applications will increase if the promise of increased life is verified by achieving a minimum of 10,000 hours of operating life. Durability plays an important role in the process of evaluation and selection of MEAs for Teledyne s Phase I contract with the NASA Glenn Research Center entitled Proton Exchange Membrane Fuel cell (PEMFC) Power Plant Technology Development for 2nd Generation Reusable Launch Vehicles (RLVs). For this contract, MEAs that are typically used for H2/air operation were selected as potential candidates for H2/O2 PEM fuel cells because their catalysts have properties suitable for O2 operation. They were purchased from several well-established MEA manufacturers who are world leaders in the manufacturing of diverse products and have committed extensive resources in an attempt to develop and fully commercialize MEA technology. A total of twelve MEAs used in H2/air operation were initially identified from these manufacturers. Based on the manufacturers specifications, nine of these were selected for evaluation. Since 10,000 hours is almost equivalent to 14 months, it was not possible to perform continuous testing with each MEA selected during Phase I of the contract. Because of the lack of time, a screening test on each MEA was performed for 400 hours under accelerated test conditions. The major criterion for an MEA pass or fail of the screening test was the gas crossover rate. If the gas crossover rate was higher than the membrane intrinsic permeability after 400 hours of testing, it was considered that the MEA had failed the test. Three types of

  12. High-strength wastewater treatment in a pure oxygen thermophilic process: 11-year operation and monitoring of different plant configurations.

    PubMed

    Collivignarelli, M C; Bertanza, G; Sordi, M; Pedrazzani, R

    2015-01-01

    This research was carried out on a full-scale pure oxygen thermophilic plant, operated and monitored throughout a period of 11 years. The plant treats 60,000 t y⁻¹ (year 2013) of high-strength industrial wastewaters deriving mainly from pharmaceuticals and detergents production and landfill leachate. Three different plant configurations were consecutively adopted: (1) biological reactor + final clarifier and sludge recirculation (2002-2005); (2) biological reactor + ultrafiltration: membrane biological reactor (MBR) (2006); and (3) MBR + nanofiltration (since 2007). Progressive plant upgrading yielded a performance improvement chemical oxygen demand (COD) removal efficiency was enhanced by 17% and 12% after the first and second plant modification, respectively. Moreover, COD abatement efficiency exhibited a greater stability, notwithstanding high variability of the influent load. In addition, the following relevant outcomes appeared from the plant monitoring (present configuration): up to 96% removal of nitrate and nitrite, due to denitrification; low-specific biomass production (0.092 kgVSS kgCODremoved⁻¹), and biological treatability of residual COD under mesophilic conditions (BOD5/COD ratio = 0.25-0.50), thus showing the complementarity of the two biological processes. PMID:25746652

  13. Pure oxygen ventilation during general anaesthesia does not result in increased postoperative respiratory morbidity but decreases surgical site infection. An observational clinical study

    PubMed Central

    Suksompong, Sirilak; Weiler, Jürgen; Zander, Rolf

    2014-01-01

    Background. Pure oxygen ventilation during anaesthesia is debatable, as it may lead to development of atelectasis. Rationale of the study was to demonstrate the harmlessness of ventilation with pure oxygen. Methods. This is a single-centre, one-department observational trial. Prospectively collected routine-data of 76,784 patients undergoing general, gynaecological, orthopaedic, and vascular surgery during 1995–2009 were retrospectively analysed. Postoperative hypoxia, unplanned ICU-admission, surgical site infection (SSI), postoperative nausea and vomiting (PONV), and hospital mortality were continuously recorded. During 1996 the anaesthetic ventilation for all patients was changed from 30% oxygen plus 70% nitrous oxide to 100% oxygen in low-flow mode. Therefore, in order to minimize the potential of confounding due to a variety of treatments being used, we directly compared years 1995 (30% oxygen) and 1997 (100%), whereas the period 1998 to 2009 is simply described. Results. Comparing 1995 to 1997 pure oxygen ventilation led to a decreased incidence of postoperative hypoxic events (4.3 to 3.0%; p < 0.0001) and hospital mortality (2.1 to 1.6%; p = 0.088) as well as SSI (8.0 to 5.0%; p < 0.0001) and PONV (21.6 to 17.5%; p < 0.0001). There was no effect on unplanned ICU-admission (1.1 to 0.9; p = 0.18). Conclusions. The observed effects may be partly due to pure oxygen ventilation, abandonment of nitrous oxide, and application of low-flow anesthesia. Pure oxygen ventilation during general anaesthesia is harmless, as long as certain standards are adhered to. It makes anaesthesia simpler and safer and may reduce clinical morbidity, such as postoperative hypoxia and surgical site infection. PMID:25320681

  14. 42 CFR 84.80 - Interchangeability of oxygen and air prohibited.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Interchangeability of oxygen and air prohibited. 84...-Contained Breathing Apparatus § 84.80 Interchangeability of oxygen and air prohibited. Approvals shall not... or respirator component which is designed or constructed to permit the interchangeable use of...

  15. 42 CFR 84.80 - Interchangeability of oxygen and air prohibited.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Interchangeability of oxygen and air prohibited. 84...-Contained Breathing Apparatus § 84.80 Interchangeability of oxygen and air prohibited. Approvals shall not... or respirator component which is designed or constructed to permit the interchangeable use of...

  16. 42 CFR 84.80 - Interchangeability of oxygen and air prohibited.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Interchangeability of oxygen and air prohibited. 84...-Contained Breathing Apparatus § 84.80 Interchangeability of oxygen and air prohibited. Approvals shall not... or respirator component which is designed or constructed to permit the interchangeable use of...

  17. 42 CFR 84.80 - Interchangeability of oxygen and air prohibited.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Interchangeability of oxygen and air prohibited. 84...-Contained Breathing Apparatus § 84.80 Interchangeability of oxygen and air prohibited. Approvals shall not... or respirator component which is designed or constructed to permit the interchangeable use of...

  18. 42 CFR 84.80 - Interchangeability of oxygen and air prohibited.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Interchangeability of oxygen and air prohibited. 84...-Contained Breathing Apparatus § 84.80 Interchangeability of oxygen and air prohibited. Approvals shall not... or respirator component which is designed or constructed to permit the interchangeable use of...

  19. A Simple Experiment To Measure the Content of Oxygen in the Air Using Heated Steel Wool

    ERIC Educational Resources Information Center

    Vera, Francisco; Rivera, Rodrigo; Nunez, Cesar

    2011-01-01

    The typical experiment to measure the oxygen content in the atmosphere uses the rusting of steel wool inside a closed volume of air. Two key aspects of this experiment that make possible a successful measurement of the content of oxygen in the air are the use of a closed atmosphere and the use of a chemical reaction that involves the oxidation of…

  20. Current status of ceramic-based membranes for oxygen separation from air.

    PubMed

    Hashim, Salwa Meredith; Mohamed, Abdul Rahman; Bhatia, Subhash

    2010-10-15

    There has been tremendous progress in membrane technology for gas separation, in particular oxygen separation from air in the last 20 years. It provides an alternative route to the existing conventional separation processes such as cryogenic distillation and pressure swing adsorption as well as cheaper production of oxygen with high purity. This review presents the recent advances of ceramic membranes for the separation of oxygen from air at high temperature. It covers the issues and problems with respect to the selectivity and separation performance. The paper also presents different approaches applied to overcome these challenges. The future directions of ceramic-based membranes for oxygen separation from air are also presented. PMID:20813344

  1. The Pathway for Oxygen: Tutorial Modelling on Oxygen Transport from Air to Mitochondrion

    PubMed Central

    Bassingthwaighte, James B.; Raymond, Gary M.; Dash, Ranjan K.; Beard, Daniel A.; Nolan, Margaret

    2016-01-01

    The ‘Pathway for Oxygen’ is captured in a set of models describing quantitative relationships between fluxes and driving forces for the flux of oxygen from the external air source to the mitochondrial sink at cytochrome oxidase. The intervening processes involve convection, membrane permeation, diffusion of free and heme-bound O2 and enzymatic reactions. While this system’s basic elements are simple: ventilation, alveolar gas exchange with blood, circulation of the blood, perfusion of an organ, uptake by tissue, and consumption by chemical reaction, integration of these pieces quickly becomes complex. This complexity led us to construct a tutorial on the ideas and principles; these first PathwayO2 models are simple but quantitative and cover: 1) a ‘one-alveolus lung’ with airway resistance, lung volume compliance, 2) bidirectional transport of solute gasses like O2 and CO2, 3) gas exchange between alveolar air and lung capillary blood, 4) gas solubility in blood, and circulation of blood through the capillary syncytium and back to the lung, and 5) blood-tissue gas exchange in capillaries. These open-source models are at Physiome.org and provide background for the many respiratory models there. PMID:26782201

  2. Method and apparatus for reducing cold-phase emissions by utilizing oxygen-enriched intake air

    DOEpatents

    Poola, Ramesh B.; Sekar, Ramanujam R.; Stork, Kevin C.

    1997-01-01

    An oxygen-enriched air intake control system for an internal combustion engine includes air directing apparatus to control the air flow into the intake of the engine. During normal operation of the engine, ambient air flowing from an air filter of the engine flows through the air directing apparatus into the intake of the engine. In order to decrease the amount of carbon monoxide (CO) and hydrocarbon (HC) emissions that tend to be produced by the engine during a short period of time after the engine is started, the air directing apparatus diverts for a short period of time following the start up of the engine at least a portion of the ambient air from the air filter through a secondary path. The secondary path includes a selectively permeable membrane through which the diverted portion of the ambient air flows. The selectively permeable membrane separates nitrogen and oxygen from the diverted air so that oxygen enriched air containing from about 23% to 25% oxygen by volume is supplied to the intake of the engine.

  3. Utilization of oxygen-enriched air in diesel engines: Fundamental considerations

    SciTech Connect

    Lahiri, D.; Mehta, P.S.; Poola, R.B.; Sekar, R.

    1997-09-01

    Utilization of oxygen-enriched air in diesel engines holds potential for low exhaust smoke and particulate emissions. The majority of the oxygen-enriched-air combustion-related studies so far are experimental in nature, where the observed results are understood on an overall basis. This paper deals with the fundamental considerations associated with the oxygen-enriched air-fuel combustion process to enhance understanding of the concept. The increase in adiabatic flame temperature, the composition of exhaust gases at equilibrium, and also the changes in thermodynamic and transport properties due to oxygen-enrichment of standard intake air are computed. The effects of oxygen-enrichment on fuel evaporation rate, ignition delay, and premixed burnt fraction are also evaluated. Appropriate changes in the ignition delay correlation to reflect the effects of oxygen-enrichment are proposed. The notion of oxygen-enrichment of standard intake air as being akin to leaning of the fuel-air mixture is refuted on the basis of the fundamentally different requirements for the oxygen-enriched combustion process.

  4. Thermodynamic, transport, and flow properties of gaseous products resulting from combustion of methane-air-oxygen

    NASA Technical Reports Server (NTRS)

    Klich, G. F.

    1976-01-01

    Results of calculations to determine thermodynamic, transport, and flow properties of combustion product gases are presented. The product gases are those resulting from combustion of methane-air-oxygen and methane-oxygen mixtures. The oxygen content of products resulting from the combustion of methane-air-oxygen mixtures was similiar to that of air; however, the oxygen contained in products of methane-oxygen combustion ranged from 20 percent by volume to zero for stoichiometric combustion. Calculations were made for products of reactant mixtures with fuel percentages, by mass, of 7.5 to 20. Results are presented for specific mixtures for a range of pressures varying from 0.0001 to 1,000 atm and for temperatures ranging from 200 to 3,800 K.

  5. Effect of heliox, oxygen and air breathing on helium bubbles after heliox diving.

    PubMed

    Hyldegaard, O; Jensen, T

    2007-01-01

    In helium saturated rat abdominal adipose tissue, helium bubbles were studied at 101.3 kPa during breathing of either heliox(80:20), 100% oxygen or air after decompression from an exposure to heliox at 405 kPa for one hour. While breathing heliox bubbles initially grew for 15-115 minutes then shrank slowly; three out of 10 bubbles disappeared in the observation period. During oxygen breathing all bubbles initially grew for 10-80 minutes then shrank until they disappeared from view; in the growing phase, oxygen caused faster growth than heliox breathing, but bubbles disappeared sooner with oxygen breathing than with heliox or air breathing. In the shrinking phase, shrinkage is faster with heliox and oxygen breathing than with air breathing. Air breathing caused consistent growth of all bubbles. With heliox and oxygen breathing, most animals survived during the observation period but with air breathing, most animals died of decompression sickness regardless of whether the surrounding atmosphere was helium or air. If recompression beyond the maximum treatment pressure of oxygen is required, these results indicate that a breathing mixture of heliox may be better than air during the treatment of decompression sickness following heliox diving. PMID:17520862

  6. Method and apparatus for monitoring oxygen partial pressure in air masks

    NASA Technical Reports Server (NTRS)

    Kelly, Mark E. (Inventor); Pettit, Donald R. (Inventor)

    2006-01-01

    Method and apparatus are disclosed for monitoring an oxygen partial pressure in an air mask and providing a tactile warning to the user. The oxygen partial pressure in the air mask is detected using an electrochemical sensor, the output signal from which is provided to a comparator. The comparator compares the output signal with a preset reference value or range of values representing acceptable oxygen partial pressures. If the output signal is different than the reference value or outside the range of values, the air mask is vibrated by a vibrating motor to alert the user to a potentially hypoxic condition.

  7. Toward a lithium-"air" battery: the effect of CO2 on the chemistry of a lithium-oxygen cell.

    PubMed

    Lim, Hyung-Kyu; Lim, Hee-Dae; Park, Kyu-Young; Seo, Dong-Hwa; Gwon, Hyeokjo; Hong, Jihyun; Goddard, William A; Kim, Hyungjun; Kang, Kisuk

    2013-07-01

    Lithium-oxygen chemistry offers the highest energy density for a rechargeable system as a "lithium-air battery". Most studies of lithium-air batteries have focused on demonstrating battery operations in pure oxygen conditions; such a battery should technically be described as a "lithium-dioxygen battery". Consequently, the next step for the lithium-"air" battery is to understand how the reaction chemistry is affected by the constituents of ambient air. Among the components of air, CO2 is of particular interest because of its high solubility in organic solvents and it can react actively with O2(-•), which is the key intermediate species in Li-O2 battery reactions. In this work, we investigated the reaction mechanisms in the Li-O2/CO2 cell under various electrolyte conditions using quantum mechanical simulations combined with experimental verification. Our most important finding is that the subtle balance among various reaction pathways influencing the potential energy surfaces can be modified by the electrolyte solvation effect. Thus, a low dielectric electrolyte tends to primarily form Li2O2, while a high dielectric electrolyte is effective in electrochemically activating CO2, yielding only Li2CO3. Most surprisingly, we further discovered that a high dielectric medium such as DMSO can result in the reversible reaction of Li2CO3 over multiple cycles. We believe that the current mechanistic understanding of the chemistry of CO2 in a Li-air cell and the interplay of CO2 with electrolyte solvation will provide an important guideline for developing Li-air batteries. Furthermore, the possibility for a rechargeable Li-O2/CO2 battery based on Li2CO3 may have merits in enhancing cyclability by minimizing side reactions. PMID:23758262

  8. Method of Separating Oxygen From Spacecraft Cabin Air to Enable Extravehicular Activities

    NASA Technical Reports Server (NTRS)

    Graf, John C.

    2013-01-01

    Extravehicular activities (EVAs) require high-pressure, high-purity oxygen. Shuttle EVAs use oxygen that is stored and transported as a cryogenic fluid. EVAs on the International Space Station (ISS) presently use the Shuttle cryo O2, which is transported to the ISS using a transfer hose. The fluid is compressed to elevated pressures and stored as a high-pressure gas. With the retirement of the shuttle, NASA has been searching for ways to deliver oxygen to fill the highpressure oxygen tanks on the ISS. A method was developed using low-pressure oxygen generated onboard the ISS and released into ISS cabin air, filtering the oxygen from ISS cabin air using a pressure swing absorber to generate a low-pressure (high-purity) oxygen stream, compressing the oxygen with a mechanical compressor, and transferring the high-pressure, high-purity oxygen to ISS storage tanks. The pressure swing absorber (PSA) can be either a two-stage device, or a single-stage device, depending on the type of sorbent used. The key is to produce a stream with oxygen purity greater than 99.5 percent. The separator can be a PSA device, or a VPSA device (that uses both vacuum and pressure for the gas separation). The compressor is a multi-stage mechanical compressor. If the gas flow rates are on the order of 5 to 10 lb (.2.3 to 4.6 kg) per day, the compressor can be relatively small [3 16 16 in. (.8 41 41 cm)]. Any spacecraft system, or other remote location that has a supply of lowpressure oxygen, a method of separating oxygen from cabin air, and a method of compressing the enriched oxygen stream, has the possibility of having a regenerable supply of highpressure, high-purity oxygen that is compact, simple, and safe. If cabin air is modified so there is very little argon, the separator can be smaller, simpler, and use less power.

  9. Mixing of Pure Air Jets with a Reacting Fuel-Rich Crossflow

    NASA Technical Reports Server (NTRS)

    Leong, M. Y.; Samuelsen, G. S.; Holdeman, J. D.

    1997-01-01

    Jets in a crossflow play an integral role in practical combustion systems such as can and annular gas turbine combustors in conventional systems, and the Rich-burn/Quick-mix/Lean-burn (RQL) combustor utilized in stationary applications and proposed for advanced subsonic and supersonic transports. The success of the RQL combustor rests with the performance of the quick-mixing section that bridges the rich and lean zones. The mixing of jet air with a rich crossflow to bring the reaction to completion in the lean zone must be performed rapidly and thoroughly in order to decrease the extent of near-stoichiometric fluid pocket formation. Fluid pockets at near-stoichiometric equivalence ratios are undesirable because the high temperatures attained accelerate pollutant formation kinetics associated with nitric oxide (NO). The present study develops a model experiment designed to reveal the processes that occur when jet air is introduced into hot effluent emanating from a fuel-rich reaction zone.

  10. A strategy for oxygen conditioning at high altitude: comparison with air conditioning.

    PubMed

    West, John B

    2015-09-15

    Large numbers of people live or work at high altitude, and many visit to trek or ski. The inevitable hypoxia impairs physical working capacity, and at higher altitudes there is also cognitive impairment. Twenty years ago oxygen enrichment of room air was introduced to reduce the hypoxia, and this is now used in dormitories, hotels, mines, and telescopes. However, recent advances in technology now allow large amounts of oxygen to be obtained from air or cryogenic oxygen sources. As a result it is now feasible to oxygenate large buildings and even institutions such as hospitals. An analogy can be drawn between air conditioning that has improved the living and working conditions of millions of people who live in hot climates and oxygen conditioning that can do the same at high altitude. Oxygen conditioning is similar to air conditioning except that instead of cooling the air, the oxygen concentration is raised, thus reducing the equivalent altitude. Oxygen conditioning on a large scale could transform living and working conditions at high altitude, where it could be valuable in homes, hospitals, schools, dormitories, company headquarters, banks, and legislative settings. PMID:26139219

  11. Spectral dependence of purely-Kerr-driven filamentation in air and argon

    NASA Astrophysics Data System (ADS)

    Ettoumi, W.; Béjot, P.; Petit, Y.; Loriot, V.; Hertz, E.; Faucher, O.; Lavorel, B.; Kasparian, J.; Wolf, J.-P.

    2010-09-01

    Based on numerical simulations, we show that higher-order nonlinear indices (up to n8 and n10, respectively) of air and argon have a dominant contribution to both focusing and defocusing in the self-guiding of ultrashort laser pulses over most of the spectrum. Plasma generation and filamentation are therefore decoupled. As a consequence, ultraviolet wavelength may not be the optimal wavelength for applications requiring to maximize ionization.

  12. Spectral dependence of purely-Kerr-driven filamentation in air and argon

    SciTech Connect

    Ettoumi, W.; Petit, Y.; Kasparian, J.; Wolf, J.-P.; Bejot, P.; Hertz, E.; Faucher, O.; Lavorel, B.; Loriot, V.

    2010-09-15

    Based on numerical simulations, we show that higher-order nonlinear indices (up to n{sub 8} and n{sub 10}, respectively) of air and argon have a dominant contribution to both focusing and defocusing in the self-guiding of ultrashort laser pulses over most of the spectrum. Plasma generation and filamentation are therefore decoupled. As a consequence, ultraviolet wavelength may not be the optimal wavelength for applications requiring to maximize ionization.

  13. Opposed jet burner studies of hydrogen combustion with pure and N2, NO-contaminated air

    NASA Technical Reports Server (NTRS)

    Guerra, Rosemary; Pellett, Gerald L.; Northam, G. Burton; Wilson, Lloyd G.

    1987-01-01

    A counterflow diffusion flame formed by an argon-bathed tubular-opposed jet burner (OJB) was used to determine the 'blowoff' and 'restore' combustion characteristics for jets of various H2/N2 mixtures and for jets of air contaminated by NO (which normally occurs in high-enthalpy airflows supplied to hypersonic test facilities for scramjet combustors). Substantial divergence of 'blowoff' and 'restore' limits occurred as H2 mass flux, M(H)2, increased, the H2 jet became richer, and the M(air)/M(H2 + N2) ratio increased from 1 to 3 (molar H2/O2 from 1 to 16). Both OJB limits were sensitive to reactant composition. One to six percent NO in air led to significant N2-corrected decreases in the M(H2) values for 'blowoff' (2-8 percent) and 'restore' (6-12 percent) for mole fractions of H2 ranging from 0.5 to 0.95. However, when H2/O2 was held constant, all N2-corrected changes in M(H2) were negligible.

  14. Universal synthesis of air stable, phase pure, controllable FeSe₂ nanocrystals.

    PubMed

    Wei, Chengrong; Bai, Yongxiao; Deng, Aiying; Bao, Yan

    2016-04-22

    Iron diselenium (FeSe2) is a promising semiconductor for thin-film solar cells because it has a suitable band gap (E(g) = 1.0 eV) and high absorption coefficient. Despite these prospects, the controllable synthesis of FeSe2 nanostructures and the diversity of their geometries has hardly been studied previously. Here, we described a successful synthesis of phase-pure, high-quality, and stable orthorhombic FeSe2 nanocrystals (NCs) in aqueous solvents. A variety of morphologies of the FeSe2 NCs were achieved by adjusting synthetic methods. FeSe2 nanoparticles with diameters of 30-100 nm were synthesized in the presence of ethylenediamine (en). Moreover, the synthetic approach developed for nanoparticles proved to be quite universal and could be modified to produce nanowires and octahedrons, with which structure the material could display high crystallinity. The diameter of the FeSe2 nanowires was 300-500 nm with a length exceeding 2 μm. The octahedrons displayed lateral dimensions of 1 μm. Meanwhile, the probable growth mechanism and fabrication process of the NCs were proposed. Polycrystalline FeSe2 thin films were fabricated by modifying the sedimentation method. The obvious photoconductivity of FeSe2 has already been observed, and it was considered to be one candidate of solar cell for the very first time. PMID:26939750

  15. Universal synthesis of air stable, phase pure, controllable FeSe2 nanocrystals

    NASA Astrophysics Data System (ADS)

    Wei, Chengrong; Bai, Yongxiao; Deng, Aiying; Bao, Yan

    2016-04-01

    Iron diselenium (FeSe2) is a promising semiconductor for thin-film solar cells because it has a suitable band gap (E g = 1.0 eV) and high absorption coefficient. Despite these prospects, the controllable synthesis of FeSe2 nanostructures and the diversity of their geometries has hardly been studied previously. Here, we described a successful synthesis of phase-pure, high-quality, and stable orthorhombic FeSe2 nanocrystals (NCs) in aqueous solvents. A variety of morphologies of the FeSe2 NCs were achieved by adjusting synthetic methods. FeSe2 nanoparticles with diameters of 30-100 nm were synthesized in the presence of ethylenediamine (en). Moreover, the synthetic approach developed for nanoparticles proved to be quite universal and could be modified to produce nanowires and octahedrons, with which structure the material could display high crystallinity. The diameter of the FeSe2 nanowires was 300-500 nm with a length exceeding 2 μm. The octahedrons displayed lateral dimensions of 1 μm. Meanwhile, the probable growth mechanism and fabrication process of the NCs were proposed. Polycrystalline FeSe2 thin films were fabricated by modifying the sedimentation method. The obvious photoconductivity of FeSe2 has already been observed, and it was considered to be one candidate of solar cell for the very first time.

  16. [Oxygen metabolism in the body during substitution of nitrogen by helium in the air].

    PubMed

    Troshikhin, G V; Isaakian, L A; Bekirova, G G

    1975-01-01

    The total gas exchange, body temperature, content of free oxygen in the quadriceps muscle and its changes upon oxygen inhalation of a known dosage (oxygen test) were measured in the Wistar rats during their one-hour exposure to a helium-oxygen atmosphere (21%) at 25 degrees C. In this atmosphere the animals displayed a 1.8 degrees decline in the body temperature, a 20.5% increase in the gas exchange and a 26% decrease of oxygen in the muscular tissue as compared with the respective parameters in the air. After the experiment during the first 20 min exposure to the normal atmosphere oxygen tests were 10-15% lower than before the experiment. These findings give evidence for an increase of oxygen exchange in the muscles of animals exposed to the helium-oxygen atmosphere at a temperature below the comfortable level. PMID:1214483

  17. Evaluation of Pure Oxygen Systems at the Umatilla Hatchery: Task 1-Review and Evaluation of Supplemental O2 Systems, Final Report.

    SciTech Connect

    Fish Factory

    1991-03-01

    The Northwest Power Planning Council has established a goal of doubling the size of salmon runs in the Columbia River Basin. The achievement of this important goal is largely dependent upon expanding the production of hatchery fish. Pure oxygen has been commonly used to increase the carrying capacity of private sector salmonid hatcheries in the Pacific Northwest. The use of supplemental oxygen to increase hatchery production is significantly less expensive than the construction of new hatcheries and might save up to $500 million in construction costs.

  18. High cell density cultivation of Pseudomonas putida KT2440 using glucose without the need for oxygen enriched air supply.

    PubMed

    Davis, Reeta; Duane, Gearoid; Kenny, Shane T; Cerrone, Federico; Guzik, Maciej W; Babu, Ramesh P; Casey, Eoin; O'Connor, Kevin E

    2015-04-01

    High Cell Density (HCD) cultivation of bacteria is essential for the majority of industrial processes to achieve high volumetric productivity (g L(-1) h(-1) ) of a bioproduct of interest. This study developed a fed batch bioprocess using glucose as sole carbon and energy source for the HCD of the well described biocatalyst Pseudomonas putida KT2440 without the supply of oxygen enriched air. Growth kinetics data from batch fermentations were used for building a bioprocess model and designing feeding strategies. An exponential followed by linearly increasing feeding strategy of glucose was found to be effective in maintaining biomass productivity while also delaying the onset of dissolved oxygen (supplied via compressed air) limitation. A final cell dry weight (CDW) of 102 g L(-1) was achieved in 33 h with a biomass productivity of 3.1 g L(-1) h(-1) which are the highest ever reported values for P. putida strains using glucose without the supply of pure oxygen or oxygen enriched air. The usefulness of the biomass as a biocatalyst was demonstrated through the production of the biodegradable polymer polyhydroxyalkanoate (PHA). When nonanoic acid (NA) was supplied to the glucose grown cells of P. putida KT2440, it accumulated 32% of CDW as PHA in 11 h (2.85 g L(-1) h(-1) ) resulting in a total of 0.56 kg of PHA in 18 L with a yield of 0.56 g PHA g NA(-1) . PMID:25311981

  19. Treatment of real coal gasification wastewater using a novel integrated system of anoxic hybrid two stage aerobic processes: performance and the role of pure oxygen microbubble.

    PubMed

    Zhuang, Haifeng; Han, Hongjun; Shan, Shengdao

    2016-06-01

    A novel integrated system of anoxic-pure oxygen microbubble-activated sludge reactor-moving bed biofilm reactor was employed in treatment of real coal gasification wastewater. The results showed the integrated system had efficient performance of pollutants removal in short hydraulic retention time. While pure oxygen microbubble with the flow rate of 1.5 L/h and NaHCO3 dosage ratio of 2:1 (amount NaHCO3 to NH4 (+)-N ratio, mol: mol) were used, the removal efficiencies of COD, total phenols (TPh) and NH4 (+)-N reached 90, 95, and 95 %, respectively, with the influent loading rates of 3.4 kg COD/(m(3) d), 0.81 kg TPh/(m(3) d), and 0.28 kg NH4 (+)-N/(m(3) d). With the recycle ratio of 300 %, the concentrations of NO2 (-)-N and NO3 (-)-N in effluent decreased to 12 and 59 mg/L, respectively. Meanwhile, pure oxygen microbubble significantly improved the enzymatic activities and affected the effluent organic compositions and reduced the foam expansion. Thus, the novel integrated system with efficient, stable, and economical advantages was suitable for engineering application. PMID:26961523

  20. Diesel cogeneration plant using oxygen enriched air and emulsified fuels

    SciTech Connect

    Marciniak, T.J.; Cole, R.L.; Sekar, R.R.; Stodolsky, F. ); Eustis, J.N. )

    1990-01-01

    The investigation of oxygen-enriched combustion of alternative fuels in diesel engines at Argonne National Laboratory (ANL) is based on information gathered from two previous Department of Energy programs. The first was the slow-speed diesel engine program which used fuels such as coal-water slurry and coal derived liquid fuels in a slow speed diesel engine. The second was the development of membrane oxygen separation equipment. The results of these programs indicated that using the new membrane oxygen enrichment technology with medium- and high-speed diesel engines would do two things. First, oxygen enrichment could reduce some emissions from stationary diesel engines, particularly smoke, particulates and hydrocarbons while significantly increasing power output. The second, was that it might be possible to use less expensive liquid fuels such as No. 4, No. 6 and residual oil emulsified with water in medium- to high-speed diesel engines. The water would (1) help to eliminate the undesirable increase in nitrogen oxide production when enriched oxygen is used, and (2) by reducing the viscosity of the heavier liquid fuels, make them easier to use in smaller industrial cogeneration applications. This program consists of four steps: preliminary feasibility study, exploratory experiments, system development, and demonstration and commercialization of an industrial cogeneration system. 3 refs., 13 figs.

  1. Effect of air preheat temperature and oxygen concentration on flame structure and emission

    SciTech Connect

    Bolz, S.; Gupta, A.K.

    1998-07-01

    The structure of turbulent diffusion flames with highly preheated combustion air (air preheat temperature in excess of 1,150 C) has been obtained using a specially designed regenerative combustion furnace. Propane gas was used as the fuel. Data have been obtained on the global flame features, spectral emission characteristics, spatial distribution of OH, CH and C{sub 2} species, and pollutants emission from the flames. The results have been obtained for various degrees of air preheat temperatures and O{sub 2} concentration in the air. The color of the flame was found to change from yellow to blue to bluish-green to green over the range of conditions examined. In some cases a hybrid color flame was also observed. The recorded images of the flame photographs were analyzed using color-analyzing software. The results show that thermal and chemical flame behavior strongly depends on the air preheat temperature and oxygen content in the air. The flame color was found to be bluish-green or green at very high air preheat temperatures and low-oxygen concentration. However, at high oxygen concentration the flame color was yellow. The flame volume was found to increase with increase in air-preheat temperature and decrease in oxygen concentration. The flame length showed a similar behavior. The concentrations of OH, CH and C{sub 2} increased with an increase in air preheat temperatures. These species exhibited a two-stage combustion behavior at low oxygen concentration and single stage combustion behavior at high oxygen concentration in the air. Stable flames were obtained for remarkably low equivalence ratios, which would not be possible with normal combustion air. Pollutants emission, including CO{sub 2} and NO{sub x} , was much lower with highly preheated combustion air at low O{sub 2} concentration than the normal air. The results also suggest uniform flow and flame thermal characteristics with conditioned highly preheated air. Highly preheated air combustion provides much

  2. 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

  3. Studies on the oxygen reduction catalyst for zinc-air battery electrode

    NASA Astrophysics Data System (ADS)

    Wang, Xianyou; Sebastian, P. J.; Smit, Mascha A.; Yang, Hongping; Gamboa, S. A.

    In this paper, perovskite type La 0.6Ca 0.4CoO 3 as a catalyst of oxygen reduction was prepared, and the structure and performance of the catalysts was examined by means of IR, X-ray diffraction (XRD), and thermogravimetric (TG). Mixed catalysts doped, some metal oxides were put also used. The cathodic polarization curves for oxygen reduction on various catalytic electrodes were measured by linear sweep voltammetry (LSV). A Zn-air battery was made with various catalysts for oxygen reduction, and the performance of the battery was measured with a BS-9300SM rechargeable battery charge/discharge device. The results showed that the perovskite type catalyst (La 0.6Ca 0.4CoO 3) doped with metal oxide is an excellent catalyst for the zinc-air battery, and can effectively stimulate the reduction of oxygen and improve the properties of zinc-air batteries, such as discharge capacity, etc.

  4. Materials and methods for the separation of oxygen from air

    DOEpatents

    MacKay, Richard; Schwartz, Michael; Sammells, Anthony F.

    2003-07-15

    Metal oxides particularly useful for the manufacture of catalytic membranes for gas-phase oxygen separation processes having the formula: O.sub.5+z where: x and x' are greater than 0; y and y' are greater than 0; x+x' is equal to 2; y+y' is less than or equal to 2; z is a number that makes the metal oxide charge neutral; A is an element selected from the lanthanide elements; A' is an element selected from Be, Mg, Ca, Sr, Ba and Ra; A" is an element selected from the f block lanthanides, Be, Mg, Ca, Sr, Ba and Ra; B is an element selected from the group consisting of Al, Ga, In or mixtures thereof and B" is Co or Mg, with the exception that when B" is Mg, A' and A" are not Mg. The metal oxides are useful for preparation of dense membranes which may be formed from dense thin films of the mixed metal oxide on a porous metal oxide element. The invention also provides methods and catalytic reactors for oxygen separation and oxygen enrichment of oxygen deficient gases which employ mixed conducting metal oxides of the above formula.

  5. Comparison of killing of gram-negative and gram-positive bacteria by pure singlet oxygen. [Salmonella typhimurium; Escherichia coli; Sarcina lutea; Staphylococcus aureus; Streptococcus lactis; Streptococcus faecalis

    SciTech Connect

    Dahl, T.A.; Midden, W.R. ); Hartman, P.E. )

    1989-04-01

    Gram-negative and gram-positive bacteria were found to display different sensitivities to pure singlet oxygen generated outside of cells. Killing curves for Salmonella typhimurium and Escherichia coli strains were indicative of multihit killing, whereas curves for Sarcina lutea, Staphylococcus aureus, Streptococcus lactis, and Streptococcus faecalis exhibited single-hit kinetics. The S. typhimurium deep rough strain TA1975, which lacks nearly all of the cell wall lipopolysaccharide coat and manifests concomitant enhancement of penetration by some exogenous substances, responded to singlet oxygen with initially faster inactivation than did the S. typhimurium wild-type strain, although the maximum rates of killing appeared to be quite similar. The structure of the cell wall thus plays an important role in susceptibility to singlet oxygen. The outer membrane-lipopolysaccharide portion of the gram-negative cell wall initially protects the bacteria from extracellular singlet oxygen, although it may also serve as a source for secondary reaction products which accentuate the rates of cell killing. S. typhimurium and E. coli strains lacking the cellular antioxidant, glutathione, showed no difference from strains containing glutathione in response to the toxic effects of singlet oxygen. Strains of Sarcina lutea and Staphylococcus aureus that contained carotenoids, however, were far more resistant to singlet oxygen lethality than were both carotenoidless mutants of the same species and other gram-positive species lacking high levels of protective carotenoids.

  6. Nitric Oxide and Oxygen Air-Contamination Effects on Extinction Limits of Non-Premixed Hydrocarbon-Air Flames for a HIFiRE Scramjet

    NASA Technical Reports Server (NTRS)

    Pellett, Gerald L.; Dawson, Lucy C.; Vaden, Sarah N.; Wilson, Lloyd G.

    2009-01-01

    Unique nitric oxide (NO) and oxygen air-contamination effects on the extinction Flame Strength (FS) of non-premixed hydrocarbon (HC) vs. air flames are characterized for 7 gaseous HCs, using a new idealized 9.3 mm straight-tube Opposed Jet Burner (OJB) at 1 atm. FS represents a laminar strain-induced extinction limit based on cross-section-average air jet velocity, Uair, that sustains combustion of a counter jet of gaseous fuel just before extinction. Besides ethane, propane, butane, and propylene, the HCs include ethylene, methane, and a 64 mole-% ethylene / 36 % methane mixture, the writer s previously recommended gaseous surrogate fuel for HIFiRE scramjet tests. The HC vs. clean air part of the work is an extension of a May 2008 JANNAF paper that characterized surrogates for the HIFiRE project that should mimic the flameholding of reformed (thermally- or catalytically-cracked) endothermic JP-like fuels. The new FS data for 7 HCs vs. clean air are thus consolidated with the previously validated data, normalized to absolute (local) axial-input strain rates, and co-plotted on a dual kinetically dominated reactivity scale. Excellent agreement with the prior data is obtained for all 7 fuels. Detailed comparisons are also made with recently published (Univ. Va) numerical results for ethylene extinction. A 2009-revised ethylene kinetic model (Univ. Southern Cal) led to predicted limits within approx. 5 % (compared to 45 %, earlier) of this writer s 2008 (and present) ethylene FSs, and also with recent independent data (Univ. Va) obtained on a new OJB system. These +/- 5 % agreements, and a hoped-for "near-identically-performing" reduced kinetics model, would greatly enhance the capability for accurate numerical simulations of surrogate HC flameholding in scramjets. The measured air-contamination effects on normalized FS extinction limits are projected to assess ongoing Arc-Heater-induced "facility test effects" of NO production (e.g., 3 mole-%) and resultant oxygen

  7. Metal-air batteries: from oxygen reduction electrochemistry to cathode catalysts.

    PubMed

    Cheng, Fangyi; Chen, Jun

    2012-03-21

    Because of the remarkably high theoretical energy output, metal-air batteries represent one class of promising power sources for applications in next-generation electronics, electrified transportation and energy storage of smart grids. The most prominent feature of a metal-air battery is the combination of a metal anode with high energy density and an air electrode with open structure to draw cathode active materials (i.e., oxygen) from air. In this critical review, we present the fundamentals and recent advances related to the fields of metal-air batteries, with a focus on the electrochemistry and materials chemistry of air electrodes. The battery electrochemistry and catalytic mechanism of oxygen reduction reactions are discussed on the basis of aqueous and organic electrolytes. Four groups of extensively studied catalysts for the cathode oxygen reduction/evolution are selectively surveyed from materials chemistry to electrode properties and battery application: Pt and Pt-based alloys (e.g., PtAu nanoparticles), carbonaceous materials (e.g., graphene nanosheets), transition-metal oxides (e.g., Mn-based spinels and perovskites), and inorganic-organic composites (e.g., metal macrocycle derivatives). The design and optimization of air-electrode structure are also outlined. Furthermore, remarks on the challenges and perspectives of research directions are proposed for further development of metal-air batteries (219 references). PMID:22254234

  8. Substantial Oxygen Flux in Dual-Phase Membrane of Ceria and Pure Electronic Conductor by Tailoring the Surface.

    PubMed

    Joo, Jong Hoon; Yun, Kyong Sik; Kim, Jung-Hwa; Lee, Younki; Yoo, Chung-Yul; Yu, Ji Haeng

    2015-07-15

    The oxygen permeation flux of dual-phase membranes, Ce0.9Gd0.1O2-δ-La0.7Sr0.3MnO3±δ (GDC/LSM), has been systematically studied as a function of their LSM content, thickness, and coating material. The electronic percolation threshold of this GDC/LSM membrane occurs at about 20 vol % LSM. The coated LSM20 (80 vol % GDC, 20 vol % LSM) dual-phase membrane exhibits a maximum oxygen flux of 2.2 mL·cm(-2)·min(-1) at 850 °C, indicating that to enhance the oxygen permeation flux, the LSM content should be adjusted to the minimum value at which electronic percolation is maintained. The oxygen ion conductivity of the dual-phase membrane is reliably calculated from oxygen flux data by considering the effects of surface oxygen exchange. Thermal cycling tests confirm the mechanical stability of the membrane. Furthermore, a dual-phase membrane prepared here with a cobalt-free coating remains chemically stable in a CO2 atmosphere at a lower temperature (800 °C) than has previously been achieved. PMID:26083529

  9. Hyperbaric oxygen treatment for air or gas embolism.

    PubMed

    Moon, R E

    2014-01-01

    Gas can enter arteries (arterial gas embolism) due to alveolar-capillary disruption (caused by pulmonary overpressurization, e.g., breath-hold ascent by divers) or veins (venous gas embolism, VGE) as a result of tissue bubble formation due to decompression (diving, altitude exposure) or during certain surgical procedures where capillary hydrostatic pressure at the incision site is sub-atmospheric. Both AGE and VGE can be caused by iatrogenic gas injection. AGE usually produces strokelike manifestations, such as impaired consciousness, confusion, seizures and focal neurological deficits. Small amounts of VGE are often tolerated due to filtration by pulmonary capillaries. However, VGE can cause pulmonary edema, cardiac "vapor lock" and AGE due to transpulmonary passage or right-to-left shunt through a patent foramen ovale. Intravascular gas can cause arterial obstruction or endothelial damage and secondary vasospasm and capillary leak. Vascular gas is frequently not visible with radiographic imaging, which should not be used to exclude the diagnosis of AGE. Isolated VGE usually requires no treatment; AGE treatment is similar to decompression sickness (DCS), with first aid oxygen then hyperbaric oxygen. Although cerebral AGE (CAGE) often causes intracranial hypertension, animal studies have failed to demonstrate a benefit of induced hypocapnia. An evidence-based review of adjunctive therapies is presented. PMID:24851554

  10. The Research of Membrane-sorption System with Increased Pressure Stream for Enriching Air with Oxygen

    NASA Astrophysics Data System (ADS)

    Korolev, M. V.; Laguntsov, N. I.; Kurchatov, I. M.

    Numerical study of single-hybrid membrane-sorption air separation system for enriching the air with oxygen were conducted. The effectiveness of such a system was analyzed, depending on selective sorbents and membranes under specified pressure ratio. A comparison of various modes membrane sorption system was done. The conclusion regarding the choice of the membrane and a sorbent for the system with a pressurized product stream was drawn.

  11. Oxygen enrichment of room air to improve well-being and productivity at high altitude.

    PubMed

    West, J B

    1999-01-01

    Increasingly, commercial activities, such as mines, and scientific facilities, such as telescopes, are being placed at very high altitudes, up to 5,000 m. Frequently workers commute to these locations from much lower altitudes, or even from sea level. In addition, large numbers of people permanently live and work at high altitudes. The hypoxia of high altitude impairs sleep quality, mental performance, productivity, and general well-being. Recently it has become feasible to raise the oxygen concentration of room air by injecting oxygen into the air conditioning. This is remarkably effective at reducing the equivalent altitude. For example, increasing the oxygen concentration by 1% (e.g., from 21% to 22%) reduces the equivalent altitude by about 300 m. In other words, a room at an altitude of 4,500 m containing 26% oxygen is effectively at an altitude of 3,000 m. Oxygen enrichment has now been tested in several studies and shown to improve sleep quality and cognitive function. The fire hazard is less than in air at sea level. This innovative technique promises to improve productivity and well-being at high altitude. PMID:10441257

  12. Layered perovskite oxide: a reversible air electrode for oxygen evolution/reduction in rechargeable metal-air batteries.

    PubMed

    Takeguchi, Tatsuya; Yamanaka, Toshiro; Takahashi, Hiroki; Watanabe, Hiroshi; Kuroki, Tomohiro; Nakanishi, Haruyuki; Orikasa, Yuki; Uchimoto, Yoshiharu; Takano, Hiroshi; Ohguri, Nobuaki; Matsuda, Motofumi; Murota, Tadatoshi; Uosaki, Kohei; Ueda, Wataru

    2013-07-31

    For the development of a rechargeable metal-air battery, which is expected to become one of the most widely used batteries in the future, slow kinetics of discharging and charging reactions at the air electrode, i.e., oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), respectively, are the most critical problems. Here we report that Ruddlesden-Popper-type layered perovskite, RP-LaSr3Fe3O10 (n = 3), functions as a reversible air electrode catalyst for both ORR and OER at an equilibrium potential of 1.23 V with almost no overpotentials. The function of RP-LaSr3Fe3O10 as an ORR catalyst was confirmed by using an alkaline fuel cell composed of Pd/LaSr3Fe3O10-2x(OH)2x·H2O/RP-LaSr3Fe3O10 as an open circuit voltage (OCV) of 1.23 V was obtained. RP-LaSr3Fe3O10 also catalyzed OER at an equilibrium potential of 1.23 V with almost no overpotentials. Reversible ORR and OER are achieved because of the easily removable oxygen present in RP-LaSr3Fe3O10. Thus, RP-LaSr3Fe3O10 minimizes efficiency losses caused by reactions during charging and discharging at the air electrode and can be considered to be the ORR/OER electrocatalyst for rechargeable metal-air batteries. PMID:23802735

  13. The Determination of the Percent of Oxygen in Air Using a Gas Pressure Sensor

    ERIC Educational Resources Information Center

    Gordon, James; Chancey, Katherine

    2005-01-01

    The experiment of determination of the percent of oxygen in air is performed in a general chemistry laboratory in which students compare the results calculated from the pressure measurements obtained with the calculator-based systems to those obtained in a water-measurement method. This experiment allows students to explore a fundamental reaction…

  14. Growth of oxygen bubbles during recharge process in zinc-air battery

    NASA Astrophysics Data System (ADS)

    Wang, Keliang; Pei, Pucheng; Ma, Ze; Chen, Huicui; Xu, Huachi; Chen, Dongfang; Xing, Haoqiang

    2015-11-01

    Rechargeable zinc-air battery used for energy storage has a serious problem of charging capacity limited by oxygen bubble coalescence. Fast removal of oxygen bubbles adhered to the charging electrode surface is of great importance for improving the charging performance of the battery. Here we show that the law of oxygen bubble growth can be achieved by means of phase-field simulation, revealing two phenomena of bubble detachment and bubble coalescence located in the charging electrode on both sides. Hydrodynamic electrolyte and partial insulation structure of the charging electrode are investigated to solve the problem of oxygen bubble coalescence during charging. Two types of rechargeable zinc-air battery are developed on the basis of different tri-electrode configurations, demonstrating that the charging performance of the battery with electrolyte flow (Ⅰ) is better than that of the battery with the partially insulated electrode (Ⅱ), while the battery Ⅱ is superior to the battery Ⅰ in the discharging performance, cost and portability. The proposed solutions and results would be available for promoting commercial application of rechargeable zinc-air batteries or other metal-air batteries.

  15. Daily changes in oxygen saturation and pulse rate associated with particulate air pollution and barometric pressure.

    PubMed

    Dockery, D W; Pope, C A; Kanner, R E; Martin Villegas, G; Schwartz, J

    1999-01-01

    Epidemiologic studies have linked fine particulate air pollution with increases in morbidity and mortality rates from cardiopulmonary complications. Although the underlying biologic mechanisms responsible for this increase remain largely unknown, potential pathways include transient declines in blood oxygenation and changes in pulse rate following exposures to particulate air pollution episodes. This study evaluated potential associations between daily measures of respirable particulate matter (PM) with pulse rate and oxygen saturation of the blood. Pulse rate and oxygen saturation (Spo2) using pulse oximetry were measured daily in 90 elderly subjects living near air pollution monitors during the winter of 1995-96 in Utah Valley. We also evaluated potential associations of oxygen saturation and pulse rate with barometric pressure. Small but statistically significant positive associations between day-to-day changes in Spo2 and barometric pressure were observed. Pulse rate was inversely associated with barometric pressure. Exposure to particulate pollution was not significantly associated with Spo2 except in male participants 80 years of age or older. Increased daily pulse rate, as well as the odds of having a pulse rate 5 or 10 beats per minute (bpm) above normal (normal is defined as the individual's mean pulse rate throughout the study period), were significantly associated with exposure to particulate pollution on the previous 1 to 5 days. The medical or biologic relevance of these increases in pulse rate following exposure to particulate air pollution requires further study. PMID:10192116

  16. A model to predict the removal of oxygen from air using a zirconia solid electrolyte membrane

    NASA Technical Reports Server (NTRS)

    Marner, W. J.; Suitor, J. W.; Glazer, C. R.

    1988-01-01

    A finite difference mathematical model has been developed to predict the removal of oxygen from air using a zirconia separation cell. The model predicts the electrical and mass transfer processes in circular disk cells with either axial or radial current flow in the electrodes and in tubular cells with axial current flow in the electrodes. Representative results are presented and discussed.

  17. The Condensation Line of Air and the Heats of Vaporization of Oxygen and Nitrogen

    NASA Technical Reports Server (NTRS)

    Furukawa, George T; Mccoskey, Robert E

    1953-01-01

    The condensation pressure of air was determined over the range of temperature from 60 to 85 K. The experimental results were slightly higher than the calculated values based on the ideal solution law. Heat of vaporization of oxygen was determined at four temperatures ranging from about 68 to 91 K and of nitrogen similarly at four temperatures ranging from 62 to 78 K.

  18. Air-water oxygen exchange in a large whitewater river

    USGS Publications Warehouse

    Hall, Robert O.; Kennedy, Theodore A.; Rosi-Marshall, Emma J.

    2012-01-01

    Air-water gas exchange governs fluxes of gas into and out of aquatic ecosystems. Knowing this flux is necessary to calculate gas budgets (i.e., O2) to estimate whole-ecosystem metabolism and basin-scale carbon budgets. Empirical data on rates of gas exchange for streams, estuaries, and oceans are readily available. However, there are few data from large rivers and no data from whitewater rapids. We measured gas transfer velocity in the Colorado River, Grand Canyon, as decline in O2 saturation deficit, 7 times in a 28-km segment spanning 7 rapids. The O2 saturation deficit exists because of hypolimnetic discharge from Glen Canyon Dam, located 25 km upriver from Lees Ferry. Gas transfer velocity (k600) increased with slope of the immediate reach. k600 was -1 in flat reaches, while k600 for the steepest rapid ranged 3600-7700 cm h-1, an extremely high value of k600. Using the rate of gas exchange per unit length of water surface elevation (Kdrop, m-1), segment-integrated k600 varied between 74 and 101 cm h-1. Using Kdrop we scaled k600 to the remainder of the Colorado River in Grand Canyon. At the scale corresponding to the segment length where 80% of the O2 exchanged with the atmosphere (mean length = 26.1 km), k600 varied 4.5-fold between 56 and 272 cm h-1 with a mean of 113 cm h-1. Gas transfer velocity for the Colorado River was higher than those from other aquatic ecosystems because of large rapids. Our approach of scaling k600 based on Kdrop allows comparing gas transfer velocity across rivers with spatially heterogeneous morphology.

  19. The effects of oxygen-enriched intake air on FFV exhaust emissions using M85

    SciTech Connect

    Poola, R.B.; Sekar, R.; Ng, H.K.; Baudino, J.H.; Colucci, C.P.

    1996-05-01

    This paper presents results of emission tests of a flexible fuel vehicle (FFV) powered by an SI engine, fueled by M85 (methanol), and supplied with oxygen-enriched intake air containing 21, 23, and 25 vol% O2. Engine-out total hydrocarbons (THCs) and unburned methanol were considerably reduced in the entire FTP cycle when the O2 content of the intake air was either 23 or 25%. However, CO emissions did not vary much, and NOx emissions were higher. HCHO emissions were reduced by 53% in bag 1, 84% in bag 2, and 59% in bag 3 of the FTP cycle with 25% oxygen-enriched intake air. During cold-phase FTP,reductions of 42% in THCs, 40% in unburned methanol, 60% in nonmethane hydrocarbons, and 45% in nonmethane organic gases (NMOGs) were observed with 25% enriched air; NO{sub x} emissions increased by 78%. Converter-out emissions were also reduced with enriched air but to a lesser degree. FFVs operating on M85 that use 25% enriched air during only the initial 127 s of cold-phase FTP or that use 23 or 25% enriched air during only cold-phase FTP can meet the reactivity-adjusted NMOG, CO, NO{sub x}, and HCHO emission standards of the transitional low-emission vehicle.

  20. Anaerobic glycolysis and specific gravity of the red blood cells of rats exposed to pure oxygen at 600 torr.

    NASA Technical Reports Server (NTRS)

    Sabine, J. C.; Leon, H. A.

    1971-01-01

    Rats were exposed to 100% oxygen at 600 torr for up to 8 days. Highly significant increases in RBC anaerobic glycolysis occurred during the first 4 days of exposure and then subsided. Two significant peaks were found, one on days 1 and 2 and one on day 4. The first peak is attributed to reticulocytosis, which was maximal after 90 minutes and had disappeared by day 3. A second mechanism must account for the peak on day 4. An interpretation of the second peak is provided by existing evidence that selective removal of older RBCs occurs during the first few days of exposure to hypobaric oxygen, with maximum effect on day 4. Results in splenectomized, sham-operated and intact animals were indistinguishable from each other. A significant decrease in RBC specific gravity was found in exposed animals with spleens intact, but not in splenectomized animals. Theoretical aspects of age-related parameters as an aid to continuous detection and evaluation of changes in RBC populations are discussed.

  1. Air-activated chemical warming devices: effects of oxygen and pressure.

    PubMed

    Raleigh, G; Rivard, R; Fabus, S

    2005-01-01

    Air-activated chemical warming devices use an exothermic chemical reaction of rapidly oxidizing iron to generate heat for therapeutic purposes. Placing these products in a hyperbaric oxygen environment greatly increases the supply of oxidant and thus increases the rate of reaction and maximum temperature. Testing for auto-ignition and maximum temperatures attained by ThermaCare Heat Wraps, Playtex Heat Therapy, and Heat Factory disposable warm packs under ambient conditions and under conditions similar to those encountered during hyperbaric oxygen treatments in monoplace and multiplace hyperbaric chambers (3 atm abs and > 95% oxygen) revealed a maximum temperature of 269 degrees F (132 degrees C) with no spontaneous ignition. The risk of thermal burn injury to adjacent skin may be increased significantly if these devices are used under conditions of hyperbaric oxygen. PMID:16509287

  2. Air separation and oxygen storage properties of hexagonal rare-earth manganites

    NASA Astrophysics Data System (ADS)

    Abughayada, Castro

    This dissertation presents evaluation results of hexagonal Y1-x RxMnO3+delta (R = Er, Y, Dy, Pr, La, Tb and Ho) rare-earth manganites for prospective air separation applications. In these materials, oxygen content is sensitively dependent on the surrounding conditions of temperature and/or oxygen partial pressure, and therefore they exhibit the ability to selectively absorb, store, and release significant amounts of separated oxygen from air. This study presents a full characterization of their thermogravimetric characteristics and air separation capabilities. With the expected potential impact of oxygen content on the physical properties of these materials, the scope of this work is expanded to explore other relevant properties such as magnetic, transport, and dilatometric characteristics. Single-phase polycrystalline samples of these materials were achieved in the hexagonal P63cm phase through solid state reaction at elevated temperatures. Further annealings under reducing conditions were required for samples with large rare-earth cations in order to suppress the competing perovskite structure and form in the anticipated hexagonal phase. Thermogravimetric measurements in oxygen atmospheres demonstrated that samples with the larger R ionic radii show rapid and reversible incorporation of significant amounts of excess oxygen (0.41 > delta > 0) at an unusual low temperature range ~190-325 °C. The reversible oxygen storage characteristics of HoMnO3+delta and related materials shown by the fast incorporation and release of interstitial oxygen at easily accessible elevated temperatures of ~300 °C demonstrate the feasibility and potential for low-cost thermal swing adsorption TSA process for oxygen separation and enrichment from air. Neutron and X-ray powder diffraction measurements confirmed the presence of three line compounds RMnO3+delta, the oxygen stoichiometric P6 3cm (delta = 0 for all R), the intermediate oxygen content superstructure phase R3c (delta ~ 0

  3. EFFECTS OF OXYGEN AND AIR MIXING ON VOID FRACTIONS IN A LARGE SCALE SYSTEM

    SciTech Connect

    Leishear, R; Hector Guerrero, H; Michael Restivo, M

    2008-09-11

    Oxygen and air mixing with spargers was performed in a 30 foot tall by 30 inch diameter column, to investigate mass transfer as air sparged up through the column and removed saturated oxygen from solution. The mixing techniques required to support this research are the focus of this paper. The fluids tested included water, water with an antifoam agent (AFA), and a high, solids content, Bingham plastic, nuclear waste simulant with AFA, referred to as AZ01 simulant, which is non-radioactive. Mixing of fluids in the column was performed using a recirculation system and an air sparger. The re-circulation system consisted of the column, a re-circulating pump, and associated piping. The air sparger was fabricated from a two inch diameter pipe concentrically installed in the column and open near the bottom of the column. The column contents were slowly re-circulated while fluids were mixed with the air sparger. Samples were rheologically tested to ensure effective mixing, as required. Once the fluids were adequately mixed, oxygen was homogeneously added through the re-circulation loop using a sintered metal oxygen sparger followed by a static mixer. Then the air sparger was re-actuated to remove oxygen from solution as air bubbled up through solution. To monitor mixing effectiveness several variables were monitored, which included flow rates, oxygen concentration, differential pressures along the column height, fluid levels, and void fractions, which are defined as the percent of dissolved gas divided by the total volume of gas and liquid. Research showed that mixing was uniform for water and water with AFA, but mixing for the AZ101 fluid was far more complex. Although mixing of AZ101 was uniform throughout most of the column, gas entrapment and settling of solids significantly affected test results. The detailed test results presented here provide some insight into the complexities of mixing and void fractions for different fluids and how the mixing process itself

  4. Oxygen and Air Nanobubble Water Solution Promote the Growth of Plants, Fishes, and Mice

    PubMed Central

    Ebina, Kosuke; Shi, Kenrin; Hirao, Makoto; Hashimoto, Jun; Kawato, Yoshitaka; Kaneshiro, Shoichi; Morimoto, Tokimitsu; Koizumi, Kota; Yoshikawa, Hideki

    2013-01-01

    Nanobubbles (<200 nm in diameter) have several unique properties such as long lifetime in liquid owing to its negatively charged surface, and its high gas solubility into the liquid owing to its high internal pressure. They are used in variety of fields including diagnostic aids and drug delivery, while there are no reports assessing their effects on the growth of lives. Nanobubbles of air or oxygen gas were generated using a nanobubble aerator (BUVITAS; Ligaric Company Limited, Osaka, Japan). Brassica campestris were cultured hydroponically for 4 weeks within air-nanobubble water or within normal water. Sweetfish (for 3 weeks) and rainbow trout (for 6 weeks) were kept either within air-nanobubble water or within normal water. Finally, 5 week-old male DBA1/J mice were bred with normal free-chaw and free-drinking either of oxygen-nanobubble water or of normal water for 12 weeks. Oxygen-nanobubble significantly increased the dissolved oxygen concentration of water as well as concentration/size of nanobubbles which were relatively stable for 70 days. Air-nanobubble water significantly promoted the height (19.1 vs. 16.7 cm; P<0.05), length of leaves (24.4 vs. 22.4 cm; P<0.01), and aerial fresh weight (27.3 vs. 20.3 g; P<0.01) of Brassica campestris compared to normal water. Total weight of sweetfish increased from 3.0 to 6.4 kg in normal water, whereas it increased from 3.0 to 10.2 kg in air-nanobubble water. In addition, total weight of rainbow trout increased from 50.0 to 129.5 kg in normal water, whereas it increased from 50.0 to 148.0 kg in air-nanobubble water. Free oral intake of oxygen-nanobubble water significantly promoted the weight (23.5 vs. 21.8 g; P<0.01) and the length (17.0 vs. 16.1 cm; P<0.001) of mice compared to that of normal water. We have demonstrated for the first time that oxygen and air-nanobubble water may be potentially effective tools for the growth of lives. PMID:23755221

  5. Oxygen and air nanobubble water solution promote the growth of plants, fishes, and mice.

    PubMed

    Ebina, Kosuke; Shi, Kenrin; Hirao, Makoto; Hashimoto, Jun; Kawato, Yoshitaka; Kaneshiro, Shoichi; Morimoto, Tokimitsu; Koizumi, Kota; Yoshikawa, Hideki

    2013-01-01

    Nanobubbles (<200 nm in diameter) have several unique properties such as long lifetime in liquid owing to its negatively charged surface, and its high gas solubility into the liquid owing to its high internal pressure. They are used in variety of fields including diagnostic aids and drug delivery, while there are no reports assessing their effects on the growth of lives. Nanobubbles of air or oxygen gas were generated using a nanobubble aerator (BUVITAS; Ligaric Company Limited, Osaka, Japan). Brassica campestris were cultured hydroponically for 4 weeks within air-nanobubble water or within normal water. Sweetfish (for 3 weeks) and rainbow trout (for 6 weeks) were kept either within air-nanobubble water or within normal water. Finally, 5 week-old male DBA1/J mice were bred with normal free-chaw and free-drinking either of oxygen-nanobubble water or of normal water for 12 weeks. Oxygen-nanobubble significantly increased the dissolved oxygen concentration of water as well as concentration/size of nanobubbles which were relatively stable for 70 days. Air-nanobubble water significantly promoted the height (19.1 vs. 16.7 cm; P<0.05), length of leaves (24.4 vs. 22.4 cm; P<0.01), and aerial fresh weight (27.3 vs. 20.3 g; P<0.01) of Brassica campestris compared to normal water. Total weight of sweetfish increased from 3.0 to 6.4 kg in normal water, whereas it increased from 3.0 to 10.2 kg in air-nanobubble water. In addition, total weight of rainbow trout increased from 50.0 to 129.5 kg in normal water, whereas it increased from 50.0 to 148.0 kg in air-nanobubble water. Free oral intake of oxygen-nanobubble water significantly promoted the weight (23.5 vs. 21.8 g; P<0.01) and the length (17.0 vs. 16.1 cm; P<0.001) of mice compared to that of normal water. We have demonstrated for the first time that oxygen and air-nanobubble water may be potentially effective tools for the growth of lives. PMID:23755221

  6. Vitamin E alters alveolar type II cell phospholipid synthesis in oxygen and air

    SciTech Connect

    Kennedy, K.A.; Snyder, J.M.; Stenzel, W.; Saito, K.; Warshaw, J.B. )

    1990-11-01

    Newborn rats were injected with vitamin E or placebo daily until 6 days after birth. The effect of vitamin E pretreatment on in vitro surfactant phospholipid synthesis was examined in isolated type II cells exposed to oxygen or air form 24 h in vitro. Type II cells were also isolated from untreated 6-day-old rats and cultured for 24 h in oxygen or air with control medium or vitamin E supplemented medium. These cells were used to examine the effect of vitamin E exposure in vitro on type II cell phospholipid synthesis and ultrastructure. Phosphatidylcholine (PC) synthesis was reduced in cells cultured in oxygen as compared with air. This decrease was not prevented by in vivo pretreatment or in vitro supplementation with vitamin E. Vitamin E pretreatment increased the ratio of disaturated PC to total PC and increased phosphatidylglycerol synthesis. The volume density of lamellar bodies in type II cells was increased in cells maintained in oxygen. Vitamin E did not affect the volume density of lamellar bodies. We conclude that in vitro hyperoxia inhibits alveolar type II cell phosphatidylcholine synthesis without decreasing lamellar body volume density and that supplemental vitamin E does not prevent hyperoxia-induced decrease in phosphatidylcholine synthesis.

  7. Afterglow chemistry of atmospheric-pressure helium-oxygen plasmas with humid air impurity

    NASA Astrophysics Data System (ADS)

    Murakami, Tomoyuki; Niemi, Kari; Gans, Timo; O'Connell, Deborah; Graham, William G.

    2014-04-01

    The formation of reactive species in the afterglow of a radio-frequency-driven atmospheric-pressure plasma in a fixed helium-oxygen feed gas mixture (He+0.5%O2) with humid air impurity (a few hundred ppm) is investigated by means of an extensive global plasma chemical kinetics model. As an original objective, we explore the effects of humid air impurity on the biologically relevant reactive species in an oxygen-dependent system. After a few milliseconds in the afterglow environment, the densities of atomic oxygen (O) decreases from 1015 to 1013 cm-3 and singlet delta molecular oxygen (O2(1D)) of the order of 1015 cm-3 decreases by a factor of two, while the ozone (O3) density increases from 1014 to 1015 cm-3. Electrons and oxygen ionic species, initially of the order of 1011 cm-3, recombine much faster on the time scale of some microseconds. The formation of atomic hydrogen (H), hydroxyl radical (OH), hydroperoxyl (HO2), hydrogen peroxide (H2O2), nitric oxide (NO) and nitric acid (HNO3) resulting from the humid air impurity as well as the influence on the afterglow chemistry is clarified with particular emphasis on the formation of dominant reactive oxygen species (ROS). The model suggests that the reactive species predominantly formed in the afterglow are major ROS O2(1D) and O3 (of the order of 1015 cm-3) and rather minor hydrogen- and nitrogen-based reactive species OH, H2O2, HNO3 and NO2/NO3, of which densities are comparable to the O-atom density (of the order of 1013 cm-3). Furthermore, the model quantitatively reproduces the experimental results of independent O and O3 density measurements.

  8. Current legal framework and practical aspects of oxygen therapy during air travel.

    PubMed

    Cascante-Rodrigo, Jose Antonio; Iridoy-Zulet, Amaia Atenea; Alfonso-Imízcoz, María

    2015-01-01

    It is unusual for pulmonologists to be familiar with the European and US regulations governing the administration of oxygen during air travel and each airline's policy in this respect. This lack of knowledge is in large part due to the scarcity of articles addressing this matter in specialized journals and the noticeably limited information provided by airlines on their websites. In this article we examine the regulations, the policies of some airlines and practical aspects that must be taken into account, so that the questions of a patient who may need to use oxygen during a flight may be answered satisfactorily. PMID:25062830

  9. Interaction of Streamer Discharges in Air and Other Oxygen-Nitrogen Mixtures

    SciTech Connect

    Luque, A.; Hundsdorfer, W.; Ebert, U.

    2008-08-15

    The interaction of streamers in nitrogen-oxygen mixtures such as air is studied. First, an efficient method for fully three-dimensional streamer simulations in multiprocessor machines is introduced. With its help, we find two competing mechanisms how two adjacent streamers can interact: through electrostatic repulsion and through attraction due to nonlocal photoionization. The nonintuitive effects of pressure and of the nitrogen-oxygen ratio are discussed. As photoionization is experimentally difficult to access, we finally suggest to measure it indirectly through streamer interactions.

  10. Response of electrochemical oxygen sensors to inert gas-air and carbon dioxide-air mixtures: measurements and mathematical modelling.

    PubMed

    Walsh, P T; Gant, S E; Dowker, K P; Batt, R

    2011-02-15

    Electrochemical oxygen gas sensors are widely used for monitoring the state of inertisation of flammable atmospheres and to warn of asphyxiation risks. It is well established but not widely known by users of such oxygen sensors that the response of the sensor is affected by the nature of the diluent gas responsible for the decrease in ambient oxygen concentration. The present work investigates the response of electrochemical sensors, with either acid or alkaline electrolytes, to gas mixtures comprising air with enhanced levels of nitrogen, carbon dioxide, argon or helium. The measurements indicate that both types of sensors over-read the oxygen concentrations when atmospheres contain high levels of helium. Sensors with alkaline electrolytes are also shown to underestimate the severity of the hazard in atmospheres containing high levels of carbon dioxide. This deviation is greater for alkaline electrolyte sensors compared to acid electrolyte sensors. A Computational Fluid Dynamics (CFD) model is developed to predict the response of an alkaline electrolyte, electrochemical gas sensor. Differences between predicted and measured sensor responses are less than 10% in relative terms for nearly all of the gas mixtures tested, and in many cases less than 5%. Extending the model to simulate responses of sensors with acid electrolytes would be straightforward. PMID:21112151

  11. Cryogenic separation of oxygen-argon mixture in natural air samples for isotopic and molecular ratios

    NASA Astrophysics Data System (ADS)

    Habeeb Rahman, Keedakkadan; Abe, Osamu

    2014-05-01

    The discovery of mass independent isotope fractionation in oxygen during the formation of ozone in the stratosphere has initiated a wide application in isotope geochemistry field. Separation of oxygen-argon mixture has become the foundation of high precision analysis of Δ17O and δ(O2/Ar) for geochemical applications. Here we present precise and simplified cryogenic separation of argon oxygen mixture from the atmospheric and dissolved air using 30/60 mesh 5A molecular sieve zeolite. A pioneer study of this method was conducted by Thiemens and Meagher in 1984. The column which is made of glass tube contains about 1.1 grams of molecular sieve zeolite and both ends of column was filled with glass wools. The experimental set up was tested for different combination of molecular sieves and slurry temperatures. We found the most efficient condition for the separation was at a column temperature of -103°C. For complete transfer of O2 and Ar mixture usually takes in 15-20 minutes time. The isotopic ratios of oxygen were analyzed using mass spectrometer (Thermo Fischer Delta Plus) relative to reference oxygen-argon mixture at 3V of m/z 32 for both sample and reference side. The signals of m/z 28, 32, and 40 were measured by dynamically to determine oxygen -argon ratio and to check nitrogen contamination. Repeated measurements of atmospheric air yielded a reproducibility (SE n=80) of 0.006, 0.004 and 0.19‰ for δ17O, δ18O and δO2/Ar respectively. The isotopic and molecular fractionation of argon- oxygen mixture during gas adsorption and desorption while using molecular sieve under liquid nitrogen temperature was studied. We have established a linear relationship governing the effect of 13X and 5A molecular sieves on molecular fractionation. And suggested the use of single 1/8" pellet 13X molecular sieve provided a negligible fractionation.

  12. Reducing the oxygen concentration of gases delivered from anaesthetic machines unadapted for medical air

    PubMed Central

    Clutton, R. E.; Schoeffmann, G.; Chesnil, M.; Gregson, R.; Reed, F.; Lawson, H.; Eddleston, M.

    2014-01-01

    High fractional concentrations of inspired oxygen (FiO2) delivered over prolonged periods produce characteristic histological changes in the lungs and airway of exposed animals. Modern medical anaesthetic machines are adapted to deliver medical air (FiO2=0.21) for the purpose of reducing FiO2; anaesthetic machines designed for the veterinary market have not been so adapted. Two inexpensive modifications that allow medical air to be added to the gas flow from veterinary anaesthetic machines are described. The advantages and disadvantages of each modification are discussed. PMID:21862470

  13. A new test method for the assessment of the arc tracking properties of wire insulation in air, oxygen enriched atmospheres and vacuum

    NASA Technical Reports Server (NTRS)

    Koenig, Dieter

    1994-01-01

    Development of a new test method suitable for the assessment of the resistance of aerospace cables to arc tracking for different specific environmental and network conditions of spacecraft is given in view-graph format. The equipment can be easily adapted for tests at different realistic electrical network conditions incorporating circuit protection and the test system works equally well whatever the test atmosphere. Test results confirm that pure Kapton insulated wire has bad arcing characteristics and ETFE insulated wire is considerably better in air. For certain wires, arc tracking effects are increased at higher oxygen concentrations and significantly increased under vacuum. All tests on different cable insulation materials and in different environments, including enriched oxygen atmospheres, resulted in a more or less rapid extinguishing of all high temperature effects at the beginning of the post-test phase. In no case was a self-maintained fire initiated by the arc.

  14. Catalytic activity trends of oxygen reduction reaction for nonaqueous Li-air batteries.

    PubMed

    Lu, Yi-Chun; Gasteiger, Hubert A; Shao-Horn, Yang

    2011-11-30

    We report the intrinsic oxygen reduction reaction (ORR) activity of polycrystalline palladium, platinum, ruthenium, gold, and glassy carbon surfaces in 0.1 M LiClO(4) 1,2-dimethoxyethane via rotating disk electrode measurements. The nonaqueous Li(+)-ORR activity of these surfaces primarily correlates to oxygen adsorption energy, forming a "volcano-type" trend. The activity trend found on the polycrystalline surfaces was in good agreement with the trend in the discharge voltage of Li-O(2) cells catalyzed by nanoparticle catalysts. Our findings provide insights into Li(+)-ORR mechanisms in nonaqueous media and design of efficient air electrodes for Li-air battery applications. PMID:22044022

  15. The Decompression Sickness and Venous Gas Emboli Consequences of Air Breaks During 100% Oxygen Prebreathe

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Gernhardt, Michael L.; Powell, Michael R.

    2005-01-01

    Not enough is known about the increased risk of hypobaric decompression sickness (DCS) and production of venous (VGE) and arterial (AGE) gas emboli following an air break in an otherwise normal 100% resting oxygen (O2) prebreathe (PB), and certainly a break in PB when exercise is used to accelerate nitrogen (N2) elimination from the tissues. Current Aeromedical Flight Rules at the Johnson Space Center about additional PB payback times are untested, possibly too conservative, and therefore not optimized for operational use.

  16. Polymerized complex synthesis of a pure 93 K Y2Ba4Cu7O(15-d) superconductor without the need of high oxygen pressure and additive catalysts

    NASA Astrophysics Data System (ADS)

    Berastegui, Pedro; Kakihana, Masato; Yoshimura, Masahiro; Mazaki, Hiromasa; Yasuoka, Hiroshi; Johansson, Lars-Gunnar; Eriksson, Sten; Borjesson, Lars; Kall, Mikael

    1993-03-01

    High-purity ceramic material of the superconducting phase Y2Ba4Cu7O(14.82) (247) has been synthesized at 870 C by the polymerized complex method using neither high oxygen pressure nor additive catalysts. The method is based on the formation of a polymer-metal complex precursor which is prepared through polyesterification between metal citrate complexes and ethylene glycol. Apart from obviating high oxygen pressure, the present preparation technique offers easier fabrication of highly pure 247 material compared with other 'wet' chemical routes, since it eliminates many steps (centrifugation, filtration, aging, and pH control). XRD and Raman scattering analyses show that the material is single-phase without any indication of secondary phases. Zero-resistance has been achieved at 88.0 K with a transition width narrower than 4 K. Complex ac magnetic susceptibility measurements confirm the presence of a single bulk superconducting 247 phase with Tc (onset) = 93.0 K and Delta-Tc (10-90 percent) = 4.5 K.

  17. Characterization of refractory matters in dyeing wastewater during a full-scale Fenton process following pure-oxygen activated sludge treatment.

    PubMed

    Bae, Wookeun; Won, Hosik; Hwang, Byungho; de Toledo, Renata Alves; Chung, Jinwook; Kwon, Kiwook; Shim, Hojae

    2015-04-28

    Refractory pollutants in raw and treated dyeing wastewaters were characterized using fractional molecular weight cut-off, Ultraviolet-vis spectrophotometry, and high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI/MS). Significant organics and color compounds remained after biological (pure-oxygen activated sludge) and chemical (Fenton) treatments at a dyeing wastewater treatment plant (flow rate ∼100,000m(3)/d). HPLC-ESI/MS analysis revealed that some organic compounds disappeared after the biological treatment but reappeared after the chemical oxidation process, and some of that were originally absent in the raw dyeing wastewater was formed after the biological or chemical treatment. It appeared that the Fenton process merely impaired the color-imparting bonds in the dye materials instead of completely degrading them. Nevertheless, this process did significantly reduce the soluble chemical oxygen demand (SCOD, 66%) and color (73%) remaining after initial biological treatment which reduced SCOD by 53% and color by 13% in raw wastewater. Biological treatment decreased the degradable compounds substantially, in such a way that the following Fenton process could effectively remove recalcitrant compounds, making the overall hybrid system more economical. In addition, ferric ion inherent to the Fenton reaction effectively coagulated particulate matters not removed via biological and chemical oxidation. PMID:25682369

  18. Synthesis of silicalite-poly(furfuryl alcohol) composite membranes for oxygen enrichment from air

    PubMed Central

    2011-01-01

    Silicalite-poly(furfuryl alcohol) [PFA] composite membranes were prepared by solution casting of silicalite-furfuryl alcohol [FA] suspension on a porous polysulfone substrate and subsequent in situ polymerization of FA. X-ray diffraction, nitrogen sorption, thermogravimetric analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to characterize silicalite nanocrystals and silicalite-PFA composite membranes. The silicalite-PFA composite membrane with 20 wt.% silicalite loading exhibits good oxygen/nitrogen selectivity (4.15) and high oxygen permeability (1,132.6 Barrers) at 50°C. Silicalite-PFA composite membranes are promising for the production of oxygen-enriched air for various applications. PMID:22209012

  19. Portable Cathode-Air Vapor-Feed Electrochemical Medical Oxygen Concentrator (OC)

    NASA Technical Reports Server (NTRS)

    Balasubramanian, Ashwin

    2015-01-01

    Missions on the International Space Station and future space exploration will present significant challenges to crew health care capabilities, particularly in the efficient utilization of onboard oxygen resources. Exploration vehicles will require lightweight, compact, and portable oxygen concentrators that can provide medical-grade oxygen from the ambient cabin air. Current pressure-swing adsorption OCs are heavy and bulky, require significant start-up periods, operate in narrow temperature ranges, and require a liquid water feed. Lynntech, Inc., has developed an electrochemical OC that operates with a cathode-air vapor feed, eliminating the need for a bulky onboard water supply. Lynntech's OC is smaller and lighter than conventional pressure-swing OCs, is capable of instant start-up, and operates over a temperature range of 5-80 C. Accomplished through a unique nanocomposite proton exchange membrane and catalyst technology, the unit delivers 4 standard liters per minute of humidified oxygen at 60 percent concentration. The technology enables both ambient-pressure operating devices for portable applications and pressurized (up to 3,600 psi) OC devices for stationary applications.

  20. Experimental and kinetic modeling of oxygen-enriched air combustion of municipal solid waste.

    PubMed

    Liu, Guo Hui; Ma, Xiao Qian; Yu, Zhaosheng

    2009-02-01

    The characteristics of oxygen-enriched air combustion of raw municipal solid waste (MSW) were studied by thermogravimetric analysis. Experiments on oxidative pyrolysis of MSW were carried out under different atmospheres (N(2), N(2):O(2)=7:3, N(2):O(2)=5:5, N(2):O(2)=4:6, and N(2):O(2)=2:8) at 30 degrees C/min. Two distinct peaks of weight loss were obtained according to the derivative thermogravimetric curves; one of them is centered on 305 degrees C with about 40% weight loss, and the second is centered on 420 degrees C with about 20% weight loss. Effects of oxygen concentration on the decomposition process and char combustion were analyzed, and then the process of oxygen-enriched air combustion of MSW was divided into four steps. Kinetic parameters were observed by direct non-linear regressions. According to the obtained data, the apparent activation energy and reaction order decreases along with the combustion process, while that of char combustion increases as oxygen concentration increases. PMID:18691862

  1. Evolution of Air Breathing: Oxygen Homeostasis and the Transitions from Water to Land and Sky

    PubMed Central

    Hsia, Connie C. W.; Schmitz, Anke; Lambertz, Markus; Perry, Steven F.; Maina, John N.

    2014-01-01

    Life originated in anoxia, but many organisms came to depend upon oxygen for survival, independently evolving diverse respiratory systems for acquiring oxygen from the environment. Ambient oxygen tension (PO2) fluctuated through the ages in correlation with biodiversity and body size, enabling organisms to migrate from water to land and air and sometimes in the opposite direction. Habitat expansion compels the use of different gas exchangers, for example, skin, gills, tracheae, lungs, and their intermediate stages, that may coexist within the same species; coexistence may be temporally disjunct (e.g., larval gills vs. adult lungs) or simultaneous (e.g., skin, gills, and lungs in some salamanders). Disparate systems exhibit similar directions of adaptation: toward larger diffusion interfaces, thinner barriers, finer dynamic regulation, and reduced cost of breathing. Efficient respiratory gas exchange, coupled to downstream convective and diffusive resistances, comprise the “oxygen cascade”—step-down of PO2 that balances supply against toxicity. Here, we review the origin of oxygen homeostasis, a primal selection factor for all respiratory systems, which in turn function as gatekeepers of the cascade. Within an organism's lifespan, the respiratory apparatus adapts in various ways to upregulate oxygen uptake in hypoxia and restrict uptake in hyperoxia. In an evolutionary context, certain species also become adapted to environmental conditions or habitual organismic demands. We, therefore, survey the comparative anatomy and physiology of respiratory systems from invertebrates to vertebrates, water to air breathers, and terrestrial to aerial inhabitants. Through the evolutionary directions and variety of gas exchangers, their shared features and individual compromises may be appreciated. PMID:23720333

  2. Oxygen electrocatalysts in metal-air batteries: from aqueous to nonaqueous electrolytes.

    PubMed

    Wang, Zhong-Li; Xu, Dan; Xu, Ji-Jing; Zhang, Xin-Bo

    2014-11-21

    With the development of renewable energy and electrified transportation, electrochemical energy storage will be more important in the future than it has ever been in the past. Although lithium-ion batteries (LIBs) are traditionally considered to be the most likeliest candidate thanks to their relatively long cycle life and high energy efficiency, their limited energy density as well as cost are still causing a bottleneck for their long-term application. Alternatively, metal-air batteries have been proposed as a very promising large-scale electricity storage technology with the replacement of the intercalation reaction mechanism by the catalytic redox reaction of a light weight metal-oxygen couple. Generally, based on the electrolyte, these metal-air batteries can be divided into aqueous and nonaqueous systems, corresponding to two typical batteries of Zn-air and Li-air, respectively. The prominent feature of both batteries are their extremely high theoretical energy density, especially for nonaqueous Li-air batteries, which far exceeds the best that can be achieved with LIBs. In this review, we focus on the major obstacle of sluggish kinetics of the cathode in both batteries, and summarize the fundamentals and recent advances related to the oxygen catalyst materials. According to the electrolyte, the aqueous and nonaqueous electrocatalytic mechanisms of the oxygen reduction and evolution reactions are discussed. Subsequently, seven groups of oxygen catalysts, which have played catalytic roles in both systems, are selectively reviewed, including transition metal oxides (single-metal oxides and mixed-metal oxides), functional carbon materials (nanostructured carbons and doped carbons), metal oxide-nanocarbon hybrid materials, metal-nitrogen complexes (non-pyrolyzed and pyrolyzed), transition metal nitrides, conductive polymers, and precious metals (alloys). Nonaqueous systems have the advantages of energy density and rechargeability over aqueous systems and have

  3. Diffusion of gases in air and its affect on oxygen deficiency hazard abatement

    SciTech Connect

    Theilacker, J.C.; White, M.J.; /Fermilab

    2005-09-01

    Density differences between air and released gases of cryogenic systems have been used to either require special oxygen deficiency hazard (ODH) control measures, or as a means of abatement. For example, it is not uncommon to assume that helium spills will quickly collect at the ceiling of a building or enclosure and will efficiently exit at the nearest vertical penetration or vent. Oxygen concentration reduction was found to be detectable during a localized helium spill throughout the entire 6.3 km Tevatron tunnel. This prompted us to perform diffusion tests in air with common gases used at Fermilab. The tests showed that gases, more readily than expected, diffused through an air column in the direction opposing buoyancy. Test results for helium and sulfur hexafluoride are presented. A system of tests were performed to better understand how easily released gases would fully mix with air and whether they remained fully mixed. The test results have been applied to a new system at Fermilab for ODH abatement.

  4. Atomic oxygen dynamics in an air dielectric barrier discharge: a combined diagnostic and modeling approach

    NASA Astrophysics Data System (ADS)

    Baldus, Sabrina; Schröder, Daniel; Bibinov, Nikita; Schulz-von der Gathen, Volker; Awakowicz, Peter

    2015-06-01

    Cold atmospheric pressure plasmas are a promising alternative therapy for treatment of chronic wounds, as they have already shown in clinical trials. In this study an air dielectric barrier discharge (DBD) developed for therapeutic use in dermatology is characterized with respect to the plasma produced reactive oxygen species, namely atomic oxygen and ozone, which are known to be of great importance to wound healing. To understand the plasma chemistry of the applied DBD, xenon-calibrated two-photon laser-induced fluorescence spectroscopy and optical absorption spectroscopy are applied. The measured spatial distributions are shown and compared to each other. A model of the afterglow chemistry based on optical emission spectroscopy is developed to cross-check the measurement results and obtain insight into the dynamics of the considered reactive oxygen species. The atomic oxygen density is found to be located mostly between the electrodes with a maximum density of {{n}\\text{O}}=6× {{10}16} cm-3 . Time resolved measurements reveal a constant atomic oxygen density between two high voltage pulses. The ozone is measured up to 3 mm outside the active plasma volume, reaching a maximum value of {{n}{{\\text{O}3}}}=3× {{10}16} cm-3 between the electrodes.

  5. Effect of Oxygenator Size on Air Removal Characteristics: A Clinical Evaluation.

    PubMed

    Stehouwer, Marco C; de Vroege, Roel; Kelder, Johannes C; Hofman, Frederik N; de Mol, Bastian A; Bruins, Peter

    2016-01-01

    During cardiopulmonary bypass (CPB), gaseous microemboli (GME) are released into the patients' arterial bloodstream. Gaseous microemboli may contribute to the adverse outcome after cardiac surgery. Recently, two oxygenator models with or without integrated arterial filter (IAF) were designed and only differ in size, leading to a change of 20% in surface area of the hollow fibers and 25% in blood velocities. The aim of this study was to assess the air removal characteristics of the inspire oxygenators with or without IAF. Sixty-eight patients were randomly assigned to four different groups: optimized adult and full adult and an additional IAF. Gaseous microemboli reduction rates were measured with a bubble counter. The number of GME reduction rates showed no differences. However, both models reduced significantly less volume of GME (optimized adult: 40.6% and full adult: 50.3%) compared with both models with IAF (88.7% and 88.5%, respectively). No significant differences of reduction rates were found between both devices without IAF and also not between both models with IAF. In conclusion, the larger inspire oxygenator tends to remove more GME. No effect from size of oxygenator device with integrated screen filter on GME reduction was observed. The inspire oxygenators with IAF may be considered as an adequate GME filter. PMID:26919180

  6. An experimental study on high temperature and low oxygen air combustion

    NASA Astrophysics Data System (ADS)

    Kim, W. B.; Chung, D. H.; Yang, J. B.; Noh, D. S.

    2000-06-01

    High temperature preheated and diluted air combustion has been confirmed as the technology, mainly applied to industrial furnaces and kilns, to realize higher thermal efficiency and lower emissions. The purpose of this study was to investigate fundamental aspects of the above-mentioned combustion experimentally and to compare with those in ordinary hydrocarbon combustion with room temperature air. The test items were exhaust gas components of CO, NOx, flame shape and radical components of CH, OH and C2, which were measured with gas analyser, camera and ICCD(Intensified Charged - Coupled Device) camera. Many phenomena as results appeared in combustion with the oxidizer, low oxygen concentration and extremely high temperature air, such as expansion of the flammable limits, increased flame propagation speed, it looked so strange as compared with those in existing combustion technology. We confirmed that such extraordinary phenomena were believable through the hot-test experiment.

  7. Consider oxygen for hydrocarbon oxidations

    SciTech Connect

    Shahani, G.H.; Gunardson, H.H.; Easterbrook, N.C.

    1996-11-01

    A number of commodity petrochemicals are produced by the selective, catalytic oxidation of hydrocarbons in the liquid and gas phase. These chemicals are the basic building blocks for a host of chemical intermediates. Producing each of these chemicals requires large volumes of air or tonnage quantities of oxygen for oxidation. This oxidation can be carried out using air, oxygen-enriched air, or pure oxygen. Many oxidation processes, such as that for making ethylene oxide, originally were implemented using air but have switched to oxygen. Other processes, such as for vinyl acetate, were developed as oxygen-based processes directly. Over the years, using pure oxygen has become an accepted practice in a number of petrochemical processes, such as those for acetaldehyde, ethylene oxide, propylene oxide, vinyl acetate, and vinyl chloride. As the authors will discuss, using oxygen provides some significant advantages. So, the authors expect that the trend of existing air-based processes converting to oxygen will continue, while new processes based on oxygen will emerge.

  8. Air-Adapted Methanosarcina acetivorans Shows High Methane Production and Develops Resistance against Oxygen Stress

    PubMed Central

    Jasso-Chávez, Ricardo; Santiago-Martínez, M. Geovanni; Lira-Silva, Elizabeth; Pineda, Erika; Zepeda-Rodríguez, Armando; Belmont-Díaz, Javier; Encalada, Rusely; Saavedra, Emma; Moreno-Sánchez, Rafael

    2015-01-01

    Methanosarcina acetivorans, considered a strict anaerobic archaeon, was cultured in the presence of 0.4–1% O2 (atmospheric) for at least 6 months to generate air-adapted cells; further, the biochemical mechanisms developed to deal with O2 were characterized. Methane production and protein content, as indicators of cell growth, did not change in air-adapted cells respect to cells cultured under anoxia (control cells). In contrast, growth and methane production significantly decreased in control cells exposed for the first time to O2. Production of reactive oxygen species was 50 times lower in air-adapted cells versus control cells, suggesting enhanced anti-oxidant mechanisms that attenuated the O2 toxicity. In this regard, (i) the transcripts and activities of superoxide dismutase, catalase and peroxidase significantly increased; and (ii) the thiol-molecules (cysteine + coenzyme M-SH + sulfide) and polyphosphate contents were respectively 2 and 5 times higher in air-adapted cells versus anaerobic-control cells. Long-term cultures (18 days) of air-adapted cells exposed to 2% O2 exhibited the ability to form biofilms. These data indicate that M. acetivorans develops multiple mechanisms to contend with O2 and the associated oxidative stress, as also suggested by genome analyses for some methanogens. PMID:25706146

  9. Oxygen Therapy

    MedlinePlus

    Oxygen therapy is a treatment that provides you with extra oxygen. Oxygen is a gas that your body needs to function. Normally, your lungs absorb oxygen from the air you breathe. But some conditions ...

  10. Increased Efficiency in SI Engine with Air Replaced by Oxygen in Argon Mixture

    SciTech Connect

    Killingsworth, N J; Rapp, V H; Flowers, D L; Aceves, S M; Chen, J; Dibble, R

    2010-01-13

    Basic engine thermodynamics predicts that spark ignited engine efficiency is a function of both the compression ratio of the engine and the specific heat ratio of the working fluid. In practice the compression ratio of the engine is often limited due to knock. Both higher specific heat ratio and higher compression ratio lead to higher end gas temperatures and increase the likelihood of knock. In actual engine cycles, heat transfer losses increase at higher compression ratios and limit efficiency even when the knock limit is not reached. In this paper we investigate the role of both the compression ratio and the specific heat ratio on engine efficiency by conducting experiments comparing operation of a single-cylinder variable-compression-ratio engine with both hydrogen-air and hydrogen-oxygen-argon mixtures. For low load operation it is found that the hydrogen-oxygen-argon mixtures result in higher indicated thermal efficiencies. Peak efficiency for the hydrogen-oxygen-argon mixtures is found at compression ratio 5.5 whereas for the hydrogen-air mixture with an equivalence ratio of 0.24 the peak efficiency is found at compression ratio 13. We apply a three-zone model to help explain the effects of specific heat ratio and compression ratio on efficiency. Operation with hydrogen-oxygen-argon mixtures at low loads is more efficient because the lower compression ratio results in a substantially larger portion of the gas to reside in the adiabatic core rather than in the boundary layer and in the crevices, leading to less heat transfer and more complete combustion.

  11. Effect of humidity on fretting wear of several pure metals

    NASA Technical Reports Server (NTRS)

    Goto, H.; Buckley, D. H.

    1984-01-01

    Fretting wear experiments with several pure metals were conducted in air at various relative humidity levels. The materials used were iron, aluminum, copper, silver, chromium, titanium, and nickel. Each pure metal had a maximum fretting wear volume at a specific humidity level RH sub max that was not dependent on mechanical factors such as contact load, fretting amplitude, and frequency in the ranges studied. The weight loss due to fretting wear at RH sub max for each pure metal decreased with increasing heat of oxygen adsorption on the metal, indicating that adhesive wear dominated at RH sub max.

  12. Communications: Elementary oxygen electrode reactions in the aprotic Li-air battery.

    PubMed

    Hummelshøj, J S; Blomqvist, J; Datta, S; Vegge, T; Rossmeisl, J; Thygesen, K S; Luntz, A C; Jacobsen, K W; Nørskov, J K

    2010-02-21

    We discuss the electrochemical reactions at the oxygen electrode of an aprotic Li-air battery. Using density functional theory to estimate the free energy of intermediates during the discharge and charge of the battery, we introduce a reaction free energy diagram and identify possible origins of the overpotential for both processes. We also address the question of electron conductivity through the Li(2)O(2) electrode and show that in the presence of Li vacancies Li(2)O(2) becomes a conductor. PMID:20170208

  13. FAST TRACK COMMUNICATION: Contrasting characteristics of sub-microsecond pulsed atmospheric air and atmospheric pressure helium-oxygen glow discharges

    NASA Astrophysics Data System (ADS)

    Walsh, J. L.; Liu, D. X.; Iza, F.; Rong, M. Z.; Kong, M. G.

    2010-01-01

    Glow discharges in air are often considered to be the ultimate low-temperature atmospheric pressure plasmas for numerous chamber-free applications. This is due to the ubiquitous presence of air and the perceived abundance of reactive oxygen and nitrogen species in air plasmas. In this paper, sub-microsecond pulsed atmospheric air plasmas are shown to produce a low concentration of excited oxygen atoms but an abundance of excited nitrogen species, UV photons and ozone molecules. This contrasts sharply with the efficient production of excited oxygen atoms in comparable helium-oxygen discharges. Relevant reaction chemistry analysed with a global model suggests that collisional excitation of O2 by helium metastables is significantly more efficient than electron dissociative excitation of O2, electron excitation of O and ion-ion recombination. These results suggest different practical uses of the two oxygen-containing atmospheric discharges, with air plasmas being well suited for nitrogen and UV based chemistry and He-O2 plasmas for excited atomic oxygen based chemistry.

  14. Composition surveys of test gas produced by a hydrogen-oxygen-air burner. [for supersonic ramjet engine

    NASA Technical Reports Server (NTRS)

    Eggers, J. M.

    1974-01-01

    As a result of the need for a uniform hot gas test stream for fuel injector development for hydrogen fueled supersonic combustion ramjet engines, an experimental study of injector configuration effect on exit flow uniformity of a hydrogen fueled oxygen replenished, combustion burner was made. Measurements used to investigate the burner nozzle exit profiles were pitot and gas sample measurements. Gas composition and associated temperature profiles were reduced to an acceptable level by burner injector modifications. The effect of the injector modifications was to redistribute the hydrogen fuel, increase the air pressure drop, promote premixing of the oxygen and air, and establish a uniform flow pattern where the oxygen-air mixture comes into contact with the hydrogen fuel. The most sensitive phenomenon which affected the composition profiles was the uniformity of the air distribution supplied to the combustion chamber.

  15. Fundamentals, development and scaleup of the air=oxygen stratified downdraft gasifier

    SciTech Connect

    Reed, T.B.; Levie, B.; Graboski, M.S.

    1988-06-01

    In 1979 the US Department of Energy, Office of Alcohol Fuels, asked the Solar Energy Research Institute to develop a process for manufacturing methanol from biomass. This can be achieved by gasification of the biomass to a ''synthesis gas'' (syn-gas) (composed of primarily hydrogen and carbon monoxide) followed by catalytic conversion of the gas to methanol. The catalytic conversion of syn-gas is a well developed commercial process. There are a number of gasifiers for wood, but most of them make either a producer gas, high on nitrogen or a pyrolysis gas high in hydrocarbons. None were developed to make syn-gas. Thus the principal technical problem was to develop a gasifier to make synthesis gas from biomass. Work was performed at SERI from 1980--1985 which resulted in the development of a prototype 1 ton/day oxygen-biomass gasifier. In 1985 a program was undertaken for Congress by the US Department of Energy (DOE) to build a commercial scale (50--200 tons/day) medium energy gasifier, based on DOE or other research. A new company, Syn-Gas Inc. (SGI), research. A contract was awarded to SGI to modify the air gasifier for oxygen operation for this project. This modification allowed extended tests of the gasifier with oxygen to determine the possibility of scaling up the SERI-SGI gasifier to 50--200 tons/day.

  16. The Extended Oxygen Window Concept for Programming Saturation Decompressions Using Air and Nitrox

    PubMed Central

    Kot, Jacek; Sicko, Zdzislaw

    2015-01-01

    Saturation decompression is a physiological process of transition from one steady state, full saturation with inert gas at pressure, to another one: standard conditions at surface. It is defined by the borderline condition for time spent at a particular depth (pressure) and inert gas in the breathing mixture (nitrogen, helium). It is a delicate and long lasting process during which single milliliters of inert gas are eliminated every minute, and any disturbance can lead to the creation of gas bubbles leading to decompression sickness (DCS). Most operational procedures rely on experimentally found parameters describing a continuous slow decompression rate. In Poland, the system for programming of continuous decompression after saturation with compressed air and nitrox has been developed as based on the concept of the Extended Oxygen Window (EOW). EOW mainly depends on the physiology of the metabolic oxygen window—also called inherent unsaturation or partial pressure vacancy—but also on metabolism of carbon dioxide, the existence of water vapor, as well as tissue tension. Initially, ambient pressure can be reduced at a higher rate allowing the elimination of inert gas from faster compartments using the EOW concept, and maximum outflow of nitrogen. Then, keeping a driving force for long decompression not exceeding the EOW allows optimal elimination of nitrogen from the limiting compartment with half-time of 360 min. The model has been theoretically verified through its application for estimation of risk of decompression sickness in published systems of air and nitrox saturation decompressions, where DCS cases were observed. Clear dose-reaction relation exists, and this confirms that any supersaturation over the EOW creates a risk for DCS. Using the concept of the EOW, 76 man-decompressions were conducted after air and nitrox saturations in depth range between 18 and 45 meters with no single case of DCS. In summary, the EOW concept describes physiology of

  17. Enhanced reactive oxygen species metabolism of air space cells in hypersensitivity pneumonitis

    SciTech Connect

    Calhoun, W.J. )

    1991-06-01

    Reactive oxygen species (ROS) are produced by phagocytic cells as part of host defense mechanisms, but these same products released by air space cells have been shown to contribute to pulmonary inflammation in interstitial lung diseases and likely represent a general mechanism of lung injury. However, the possible contribution of these compounds to lung inflammation in hypersensitivity pneumonitis (HP) has yet to be reported. We performed 11 bronchoalveolar lavage (BAL) studies in six patients with HP and compared the results with results from studies in 21 healthy normal volunteers. In patients with HP, spontaneous and stimulated measures of ROS metabolism by air space cells were significantly higher than those seen in normal volunteers. When alveolar macrophages were purified by depleting neutrophils and eosinophils on density gradients of Percoll (specific gravity 1.075 gm/ml), ROS metabolism remained elevated when compared with that in cells obtained from healthy controls, confirming that alveolar macrophage ROS metabolism is enhanced in patients with HP. Further, we found significant elevations in BAL total protein, lymphocytes, eosinophils, and neutrophils in patients with HP when they were compared with normal volunteers, with an increased proportion of BAL T lymphocytes expressing CD8 and natural killer surface antigens, consistent with previous work. Lavage samples from patients with HP with clinically active disease had higher proportions of BAL eosinophils and concentrations of total protein, lower forced expiratory volume in 1 second, lower forced vital capacity, and lower arterial oxygen tensions, and higher indices of ROS metabolism than samples from patients with HP with inactive disease. HP is associated with evidence of air space inflammation, to which alveolar macrophage-derived ROS may contribute.

  18. The Extended Oxygen Window Concept for Programming Saturation Decompressions Using Air and Nitrox.

    PubMed

    Kot, Jacek; Sicko, Zdzislaw; Doboszynski, Tadeusz

    2015-01-01

    Saturation decompression is a physiological process of transition from one steady state, full saturation with inert gas at pressure, to another one: standard conditions at surface. It is defined by the borderline condition for time spent at a particular depth (pressure) and inert gas in the breathing mixture (nitrogen, helium). It is a delicate and long lasting process during which single milliliters of inert gas are eliminated every minute, and any disturbance can lead to the creation of gas bubbles leading to decompression sickness (DCS). Most operational procedures rely on experimentally found parameters describing a continuous slow decompression rate. In Poland, the system for programming of continuous decompression after saturation with compressed air and nitrox has been developed as based on the concept of the Extended Oxygen Window (EOW). EOW mainly depends on the physiology of the metabolic oxygen window--also called inherent unsaturation or partial pressure vacancy--but also on metabolism of carbon dioxide, the existence of water vapor, as well as tissue tension. Initially, ambient pressure can be reduced at a higher rate allowing the elimination of inert gas from faster compartments using the EOW concept, and maximum outflow of nitrogen. Then, keeping a driving force for long decompression not exceeding the EOW allows optimal elimination of nitrogen from the limiting compartment with half-time of 360 min. The model has been theoretically verified through its application for estimation of risk of decompression sickness in published systems of air and nitrox saturation decompressions, where DCS cases were observed. Clear dose-reaction relation exists, and this confirms that any supersaturation over the EOW creates a risk for DCS. Using the concept of the EOW, 76 man-decompressions were conducted after air and nitrox saturations in depth range between 18 and 45 meters with no single case of DCS. In summary, the EOW concept describes physiology of

  19. The Role of Oxygen in Determining Upper Thermal Limits in Lottia digitalis under Air Exposure and Submersion.

    PubMed

    Bjelde, Brittany E; Miller, Nathan A; Stillman, Jonathon H; Todgham, Anne E

    2015-01-01

    Oxygen limitation of aerobic metabolism is hypothesized to drive organismal thermal tolerance limits. Differences in oxygen availability in air and water may underlie observed differences in upper thermal tolerance of intertidal limpets if oxygen is limiting in submerged environments. We explored how cardiac performance (heart rate, breakpoint temperature [BPT], flat-line temperature [FLT], and temperature sensitivity) was affected by hyperoxia and hypoxia in the finger limpet, Lottia digitalis, under air exposure and submersion. Upper thermal tolerance limits were unchanged by increasing availability of oxygen, although air-exposed limpets were able to maintain cardiac function to higher temperatures than submerged limpets. Maximum heart rate did not increase with greater partial pressure of oxygen (Po2), suggesting that tissue Po2 levels are likely maximized during normoxia. Hypoxia reduced breakpoint BPTs and FLTs in air-exposed and submerged limpets and accentuated the difference in BPTs between the two groups through greater reductions in BPT in submerged limpets. Differences in respiratory structures and the degree to which thermal limits are already maximized may play significant roles in determining how oxygen availability influences upper temperature tolerance. PMID:26658246

  20. Oxygen Therapy

    MedlinePlus

    ... 85-95% pure oxygen. The concentrator runs on electricity or a battery. A concentrator for home usually ... systems deliver 100% oxygen, and do not require electricity. A small canister can be filled from the ...

  1. Detection and quantification of reactive oxygen species (ROS) in indoor air.

    PubMed

    Montesinos, V Nahuel; Sleiman, Mohamad; Cohn, Sebastian; Litter, Marta I; Destaillats, Hugo

    2015-06-01

    Reactive oxygen species (ROS), such as free radicals and peroxides, are environmental trace pollutants potentially associated with asthma and airways inflammation. These compounds are often not detected in indoor air due to sampling and analytical limitations. This study developed and validated an experimental method to sample, identify and quantify ROS in indoor air using fluorescent probes. Tests were carried out simultaneously using three different probes: 2',7'-dichlorofluorescin (DCFH) to detect a broad range of ROS, Amplex ultra Red® (AuR) to detect peroxides, and terephthalic acid (TPA) to detect hydroxyl radicals (HO(•)). For each test, air samples were collected using two impingers in series kept in an ice bath, containing each 10 mL of 50 mM phosphate buffer at pH 7.2. In tests with TPA, that probe was also added to the buffer prior to sampling; in the other two tests, probes and additional reactants were added immediately after sampling. The concentration of fluorescent byproducts was determined fluorometrically. Calibration curves were developed by reacting DCFH and AuR with known amounts of H2O2, and using known amounts of 2-hydroxyterephthalic acid (HTPA) for TPA. Low detection limits (9-13 nM) and quantification limits (18-22 nM) were determined for all three probes, which presented a linear response in the range 10-500 nM for AuR and TPA, and 100-2000 nM for DCFH. High collection efficiency (CE) and recovery efficiency (RE) were observed for DCFH (CE=RE=100%) and AuR (CE=100%; RE=73%) by sampling from a laboratory-developed gas phase H2O2 generator. Interference of co-occurring ozone was evaluated and quantified for the three probes by sampling from the outlet of an ozone generator. The method was demonstrated by sampling air emitted by two portable air cleaners: a strong ozone generator (AC1) and a plasma generator (AC2). High ozone levels emitted by AC1 did not allow for simultaneous determination of ROS levels due to high background levels

  2. Rotationally resolved water dimer spectra in atmospheric air and pure water vapour in the 188-258 GHz range.

    PubMed

    Serov, E A; Koshelev, M A; Odintsova, T A; Parshin, V V; Tretyakov, M Yu

    2014-12-21

    New experimental results regarding "warm" water dimer spectra under equilibrium conditions are presented. An almost equidistant series of six peaks corresponding to the merged individual lines of the bound dimer with consecutive rotational quantum numbers is studied in the 188-258 GHz frequency range in water vapour over a broad range of pressures and temperatures relevant to the Earth's atmosphere. The series is a continuation of the sequence detected earlier at lower frequencies at room temperature. The signal-to-noise ratio of the observed spectra allowed investigating their evolution, when water vapour was diluted by atmospheric air with partial pressure from 0 up to 540 Torr. Analysis of the obtained spectra permitted determining the dimerization constant as well as the hydrogen bond dissociation energy and the dimer spectral parameters, including the average coefficient of collisional broadening of individual lines by water vapour and air. The manifestation of metastable states of the dimer in the observed spectra is assessed. The contribution of three possible pair states of water molecules to the second virial coefficient is evaluated over the broad range of temperatures. The work supports the significant role of the water dimer in atmospheric absorption and related processes. PMID:25363156

  3. A Metal-Free, Free-Standing, Macroporous Graphene@g-C₃N₄ Composite Air Electrode for High-Energy Lithium Oxygen Batteries.

    PubMed

    Luo, Wen-Bin; Chou, Shu-Lei; Wang, Jia-Zhao; Zhai, Yu-Chun; Liu, Hua-Kun

    2015-06-01

    The nonaqueous lithium oxygen battery is a promising candidate as a next-generation energy storage system because of its potentially high energy density (up to 2-3 kW kg(-1)), exceeding that of any other existing energy storage system for storing sustainable and clean energy to reduce greenhouse gas emissions and the consumption of nonrenewable fossil fuels. To achieve high energy density, long cycling stability, and low cost, the air electrode structure and the electrocatalysts play important roles. Here, a metal-free, free-standing macroporous graphene@graphitic carbon nitride (g-C3N4) composite air cathode is first reported, in which the g-C3N4 nanosheets can act as efficient electrocatalysts, and the macroporous graphene nanosheets can provide space for Li2O2 to deposit and also promote the electron transfer. The electrochemical results on the graphene@g-C3N4 composite air electrode show a 0.48 V lower charging plateau and a 0.13 V higher discharging plateau than those of pure graphene air electrode, with a discharge capacity of nearly 17300 mA h g(-1)(composite) . Excellent cycling performance, with terminal voltage higher than 2.4 V after 105 cycles at 1000 mA h g(-1)(composite) capacity, can also be achieved. Therefore, this hybrid material is a promising candidate for use as a high energy, long-cycle-life, and low-cost cathode material for lithium oxygen batteries. PMID:25688745

  4. Combination air-blown and oxygen-blown underground coal gasification process

    SciTech Connect

    Puri, R.; Arri, L.E.; Gash, W.

    1987-05-05

    A method is described of underground coal gasification in a coal seam between linked injection and production wells comprising igniting coal located between the wells, injecting steam and oxygen into the coal seam through the injection well to maintain combustion between the wells thereby producing a medium-Btu gas. The Btu content of the gas is gradually decreased, switching to air injection into the coal seam through the injection well when the Btu content has reached a predetermined point thereby continuing combustion with the production of a low-Btu content gas suitable for consumption at facilities located on the surface in the vicinity of the seam for the production of utilities required at the seam.

  5. "Ene" Reactions of Singlet Oxygen at the Air-Water Interface.

    PubMed

    Malek, Belaid; Fang, William; Abramova, Inna; Walalawela, Niluksha; Ghogare, Ashwini A; Greer, Alexander

    2016-08-01

    Prenylsurfactants [(CH3)2C═CH(CH2)nSO3(-) Na(+) (n = 4, 6, or 8)] were designed to probe the "ene" reaction mechanism of singlet oxygen at the air-water interface. Increasing the number of carbon atoms in the hydrophobic chain caused an increase in the regioselectivity for a secondary rather than tertiary surfactant hydroperoxide, arguing for an orthogonal alkene on water. The use of water, deuterium oxide, and H2O/D2O mixtures helped to distinguish mechanistic alternatives to homogeneous solution conditions that include dewetting of the π bond and an unsymmetrical perepoxide transition state in the hydroperoxide-forming step. The prenylsurfactants and a photoreactor technique allowed a certain degree of interfacial control of the hydroperoxidation reaction on a liquid support, where the oxidant (airborne (1)O2) is delivered as a gas. PMID:27385423

  6. Effect of oxygen and heliox breathing on air bubbles in adipose tissue during 25-kPa altitude exposures.

    PubMed

    Randsøe, T; Kvist, T M; Hyldegaard, O

    2008-11-01

    At altitude, bubbles are known to form and grow in blood and tissues causing altitude decompression sickness. Previous reports indicate that treatment of decompression sickness by means of oxygen breathing at altitude may cause unwanted bubble growth. In this report we visually followed the in vivo changes of micro air bubbles injected into adipose tissue of anesthetized rats at 101.3 kPa (sea level) after which they were decompressed from 101.3 kPa to and held at 25 kPa (10,350 m), during breathing of oxygen or a heliox(34:66) mixture (34% helium and 66% oxygen). Furthermore, bubbles were studied during oxygen breathing preceded by a 3-h period of preoxygenation to eliminate tissue nitrogen before decompression. During oxygen breathing, bubbles grew from 11 to 198 min (mean: 121 min, +/-SD 53.4) after which they remained stable or began to shrink slowly. During heliox breathing bubbles grew from 30 to 130 min (mean: 67 min, +/-SD 31.0) from which point they stabilized or shrank slowly. No bubbles disappeared during either oxygen or heliox breathing. Preoxygenation followed by continuous oxygen breathing at altitude caused most bubbles to grow from 19 to 179 min (mean: 51 min, +/-SD 47.7) after which they started shrinking or remained stable throughout the observation period. Bubble growth time was significantly longer during oxygen breathing compared with heliox breathing and preoxygenated animals. Significantly more bubbles disappeared in preoxygenated animals compared with oxygen and heliox breathing. Preoxygenation enhanced bubble disappearance compared with oxygen and heliox breathing but did not prevent bubble growth. The results indicate that oxygen breathing at 25 kPa promotes air bubble growth in adipose tissue regardless of the tissue nitrogen pressure. PMID:18756005

  7. Measurements of Lorentz air-broadening coefficients and relative intensities in the H2O-16 pure rotational and nu2 bands from long horizontal path atmospheric spectra

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Smith, Mary Ann H.; Goldman, Aaron; Malathy Devi, V.

    1991-01-01

    Lorentz air-broadening coefficients and relative intensities have been measured for forty-three lines in the pure rotational band and twenty lines in the nu2 band of H2O-16 between 800 and 1150/cm. The results were derived from analysis of nine 0.017/cm-resolution atmospheric absorption spectra recorded over horizontal paths of 0.5-1.5 km with the McMath Fourier transform spectrometer and main solar telescope operated on Kitt Peak by the National Solar Observatory. A nonlinear least-squares spectral fitting technique was used in the spectral analysis. The results are compared with previous measurements and calculations. In most cases, the measured pressure-broadening coefficients and intensities are significantly different from the values in the 1986 HITRAN line parameters compilation.

  8. An Experimental Study of Unconfined Hydrogen/Oxygen and Hydrogen/Air Explosions

    NASA Technical Reports Server (NTRS)

    Richardson, Erin; Skinner, Troy; Blackwood, James; Hays, Michael; Bangham, Mike; Jackson, Austin

    2014-01-01

    Development tests are being conducted to characterize unconfined Hydrogen/air and Hydrogen/Oxygen blast characteristics. Most of the existing experiments for these types of explosions address contained explosions, like shock tubes. Therefore, the Hydrogen Unconfined Combustion Test Apparatus (HUCTA) has been developed as a gaseous combustion test device for determining the relationship between overpressure, impulse, and flame speed at various mixture ratios for unconfined reactions of hydrogen/oxygen and hydrogen/air. The system consists of a central platform plumbed to inject and mix component gasses into an attached translucent bag or balloon while monitoring hydrogen concentration. All tests are ignited with a spark with plans to introduce higher energy ignition sources in the future. Surrounding the platform are 9 blast pressure "Pencil" probes. Two high-speed cameras are used to observe flame speed within the combustion zone. The entire system is raised approx. 6 feet off the ground to remove any ground reflection from the measurements. As of this writing greater than 175 tests have been performed and include Design of Experiments test sets. Many of these early tests have used bags or balloons between approx. 340L and approx. 1850L to quantify the effect of gaseous mixture ratio on the properties of interest. All data acquisition is synchronized between the high-speed cameras, the probes, and the ignition system to observe flame and shock propagation. Successful attempts have been made to couple the pressure profile with the progress of the flame front within the combustion zone by placing a probe within the bag. Overpressure and impulse data obtained from these tests are used to anchor engineering analysis tools, CFD models and in the development of blast and fragment acceleration models.

  9. Oxygenated hydrocarbons in ambient air: Methods and measurements using solid-phase microextraction

    SciTech Connect

    Zhou, J.; McLaren, R.

    1999-07-01

    A method is described for the measurement of oxygenated and aromatic hydrocarbons in ambient air that combines the use of solid-phase microextraction with GC-MS. The method has proven to be sensitive enough to measure a range of species above the detection limit at urban and rural locations. Advantages and disadvantages of the method are discussed following the discussion of calibration and measurement methods. Measured mixing ratios are reported for oxygenated and aromatic hydrocarbons in the urban city of Toronto and at a rural forested site in Borden, Ontario. Correlations between different species are used to identify possible sources. At the Borden site, measurements at two levels on a tower through the forest canopy are used to discuss possible sources of species at that site. A unifying theme for both sites is the observation of similar and high median levels of methanol, acetone and acetaldehyde. The comparison of data from the urban and forested sites in this study do not provide evidence for a significant biogenic source of methanol as seen in the southern USA, although it is not discounted.

  10. Oxygen reduction and evolution reactions of air electrodes using a perovskite oxide as an electrocatalyst

    NASA Astrophysics Data System (ADS)

    Nishio, Koji; Molla, Sergio; Okugaki, Tomohiko; Nakanishi, Shinji; Nitta, Iwao; Kotani, Yukinari

    2015-03-01

    The oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) of air electrodes consisting of La0.5Sr0.5CoO3 and/or carbon in the electrocatalyst layer are studied by using two types of gas diffusion electrodes. Cyclic voltammetry and square wave voltammetry studies reveal very low ORR activity of carbon-free perovskite and remarkably enhanced ORR of perovskite-carbon composites. The ORR current density at -0.5 V vs. Hg/HgO is higher than 200 mA cm-2 in a wide range of perovskite-carbon composition, suggesting good peroxide reducing capability of the perovskite. The ORR mechanisms of perovskite-carbon composites are consistent with the 2+2-electron mechanisms. The ORR and OER properties of perovskite-carbon composite electrodes are significantly influenced by the carbon species. The electrode exhibits a higher ORR current density, but inferior cycling performances when a carbon material with a higher specific surface area is used, and vice versa. Under a current density of 20 mA cm-2 and ORR and OER durations of 30 min, a gas diffusion type electrode consists of La0.5Sr0.5CoO3 and a low surface area carbon are capable of more than 150 cycles.

  11. Mitigation of electron attachment to oxygen in high pressure air plasmas by vibrational excitation

    NASA Astrophysics Data System (ADS)

    Frederickson, K.; Lee, W.; Palm, P.; Adamovich, I. V.; Rich, J. W.; Lempert, W. R.

    2007-05-01

    A series of time resolved microwave attenuation measurements are performed of the electron number density of an electron beam generated, CO laser excited nonequilibrium O2/N2 plasma. Resonant absorption of infrared radiation from the CO laser produces the nonequilibrium state, in which the heavy species vibrational modes are disproportionately excited, compared to the rotational and translational modes (Tvib≈2000-3000K vs TR /T≈300K). It is shown that this results in an increase in the plasma free electron lifetime by two orders of magnitude compared to the unexcited cold gas, an effect which is ascribed to complete mitigation of rapid three-body electron attachment to molecular oxygen. A series of heavy species filtered pure rotational Raman scattering measurements are also presented, which exhibit minimal temperature change (+50K), indicating that the observed lifetime increase cannot be due to heavy-species thermal effects. Finally, computational modeling results infer an increase in the rate of O2- detachment by four to five orders of magnitude, compared to the equilibrium value.

  12. [Research on accurate measurement of oxygen content in coal using laser-induced breakdown spectroscopy in air environment].

    PubMed

    Yin, Wang-bao; Zhang, Lei; Wang, Le; Dong, Lei; Ma, Wei-guang; Jia, Suo-tang

    2012-01-01

    A technique about accurate measurement of oxygen content in coal in air environment using laser-induced breakdown spectroscopy (LIBS) is introduced in the present paper. Coal samples were excited by the laser, and plasma spectra were obtained. Combining internal standard method, temperature correction method and multi-line methods, the oxygen content of coal samples was precisely measured. The measurement precision is not less than 1.37% for oxygen content in coal analysis, so is satisfied for the requirement of coal-fired power plants in coal analysis. This method can be used in surveying, environmental protection, medicine, materials, archaeological and food safety, biochemical and metallurgy application. PMID:22497159

  13. Zinc/air battery R and D research and development of bifunctional oxygen electrode: Tasks I and II, Final report

    SciTech Connect

    Klein, M.; Viswanathan, S.

    1986-12-01

    Studies were conducted of the bifunctional oxygen electrode. The development of a rechargeable metal-oxygen (air) cell has been hampered to a great extent by the lack of a stable and cost effective oxygen electrode capable of use during both charge and discharge. The first type of bifunctional electrode consists of two distinct catalytifc layers. The oxygen reduction catalyst layer containing a supported gold catalyst is in contact with a hydrophilic nickel layer in which evolution of oxygen takes place. Loadings of gold from 0.5 to 1.0 mg/cm/sup 2/ were investigated; carbon, graphite, metal, and spinel oxides were evaluated as substrates. The second part of the research effort was centered on developing a reversible oxygen electrode containing only one catalytic layer for both reduction and evolution of oxygen. The work was directed specifically to the study of perovskite type of oxides with the composition AA/sup 1/BO/sub 3/ where A is an element of the lanthanide series, A/sup 1/ is an alkaline earth metal and B, a first row transition element. Initial polarization data obtained in unscrubbed air gave a value of approximately 200 millivolts vs Hg/HgO reference electrode at a current density of 50 ma/cm/sup 2/. Electrodes were made both by roll-bonding and by pelletizing techniques and tested for polarization and cycle life. This study also indicates the optimum process conditions for the manufacture of oxides and fabrication of electrodes.

  14. Effect of hypobaric air, oxygen, heliox (50:50), or heliox (80:20) breathing on air bubbles in adipose tissue.

    PubMed

    Hyldegaard, O; Madsen, J

    2007-09-01

    The fate of bubbles formed in tissues during decompression to altitude after diving or due to accidental loss of cabin pressure during flight has only been indirectly inferred from theoretical modeling and clinical observations with noninvasive bubble-measuring techniques of intravascular bubbles. In this report we visually followed the in vivo resolution of micro-air bubbles injected into adipose tissue of anesthetized rats decompressed from 101.3 kPa to and held at 71 kPa corresponding to approximately 2.750 m above sea level, while the rats breathed air, oxygen, heliox (50:50), or heliox (80:20). During air breathing, bubbles initially grew for 30-80 min, after which they remained stable or began to shrink slowly. Oxygen breathing caused an initial growth of all bubbles for 15-85 min, after which they shrank until they disappeared from view. Bubble growth was significantly greater during breathing of oxygen compared with air and heliox breathing mixtures. During heliox (50:50) breathing, bubbles initially grew for 5-30 min, from which point they shrank until they disappeared from view. After a shift to heliox (80:20) breathing, some bubbles grew slightly for 20-30 min, then shrank until they disappeared from view. Bubble disappearance was significantly faster during breathing of oxygen and heliox mixtures compared with air. In conclusion, the present results show that oxygen breathing at 71 kPa promotes bubble growth in lipid tissue, and it is possible that breathing of heliox may be beneficial in treating decompression sickness during flight. PMID:17600159

  15. The Decompression Sickness and Venous Gas Emboli Consequences of Air Breaks During 100% Oxygen Prebreathe

    NASA Technical Reports Server (NTRS)

    Conkin, J.; Gernhardt, M. L.; Powell, M. R.

    2004-01-01

    Not enough is known about the increased risk of hypobaric decompression sickness (DCS) and production of venous (VGE) and arterial (AGE) gas emboli following an air break in an otherwise normal 100% resting oxygen (O2) prebreathe (PB), and certainly a break in PB when exercise is used to accelerate nitrogen (N2) elimination from the tissues. Current Aeromedical Flight Rules at the Johnson Space Center about additional PB payback times are untested, possibly too conservative, and therefore not optimized for operational use. A 10 min air break at 90 min into a 120 min PB that includes initial dual-cycle ergometry for 10 min will show a measurable increase in the risk of DCS and VGE after ascent to 4.3 psia compared to a 10 min break at 15 min into the PB, or when there is no break in PB. Data collection with humans begins in 2005, but here we first evaluate the hypothesis using three models of tissue N2 kinetics: Model I is a simple single half-time compartment exponential model, Model II is a three compartment half-time exponential model, and Model III is a variable half-time compartment model where the percentage of maximum O2 consumption for the subject during dual-cycle ergometry exercise defines the half-time compartment. Model I with large rate constants to simulate an exercise effect always showed a late break in PB had the greatest consequence. Model II showed an early break had the greatest consequence. Model III showed there was no difference between early or late break in exercise PB. Only one of these outcomes will be observed when humans are tested. Our results will favor one of these models, and so advance our understanding of tissue N2 kinetics, and of altitude DCS after an air break in PB.

  16. Comparison of effects of ProSeal LMA™ laryngeal mask airway cuff inflation with air, oxygen, air:oxygen mixture and oxygen:nitrous oxide mixture in adults: A randomised, double-blind study

    PubMed Central

    Sharma, Mona; Sinha, Renu; Trikha, Anjan; Ramachandran, Rashmi; Chandralekha, C

    2016-01-01

    Background and Aims: Laryngeal mask airway (LMA) cuff pressure increases when the air is used for the cuff inflation during oxygen: nitrous oxide (O2:N2O) anaesthesia, which may lead to various problems. We compared the effects of different gases for ProSeal LMA™ (PLMA) cuff inflation in adult patients for various parameters. Methods: A total of 120 patients were randomly allocated to four groups, according to composition of gases used to inflate the PLMA cuff to achieve 40 cmH2 O cuff pressure, air (Group A), 50% O2 :air (Group OA), 50% O2:N2O (Group ON) and 100% O2 (Group O). Cuff pressure, cuff volume and ventilator parameters were monitored intraoperatively. Pharyngolaryngeal parameters were assessed at 1, 2 and 24 h postoperatively. Statistical analysis was performed using ANOVA, Fisher's exact test and step-wise logistic regression. Results: Cuff pressure significantly increased at 10, 15 and 30 min in Group A, OA and O from initial pressure. Cuff pressure decreased at 5 min in Group ON (36.6 ± 3.5 cmH2 O) (P = 0.42). PLMA cuff volume increased in Group A, OA, O, but decreased in Group ON (6.16 ± 2.8 ml [P < 0.001], 4.7 ± 3.8 ml [P < 0.001], 1.4 ± 3.19 ml [P = 0.023] and − 1.7 ± 4.9 ml [P = 0.064], respectively), from basal levels. Ventilatory parameters were comparable in all four groups. There was no significant association between sore throat and cuff pressure, with odds ratio 1.002. Conclusion: Cuff inflation with 50% O2:N2O mixture provided more stable cuff pressure in comparison to air, O2 :air, 100% O2 during O2:N2O anaesthesia. Ventilatory parameters did not change with variation in PLMA cuff pressure. Post-operative sore throat had no correlation with cuff pressure. PMID:27601739

  17. Investigations of oxygen reduction reactions in non-aqueous electrolytes and the lithium-air battery

    NASA Astrophysics Data System (ADS)

    O'Laoire, Cormac Micheal

    Unlocking the true energy capabilities of the lithium metal negative electrode in a lithium battery has until now been limited by the low capacity intercalation and conversion reactions at the positive electrodes. This is overcome by removing these electrodes and allowing lithium to react directly with oxygen in the atmosphere forming the Li-air battery. Chapter 2 discusses the intimate role of electrolyte, in particular the role of ion conducting salts on the mechanism and kinetics of oxygen reduction in non-aqueous electrolytes designed for such applications and in determining the reversibility of the electrode reactions. Such fundamental understanding of this high energy density battery is crucial to harnessing its full energy potential. The kinetics and mechanisms of O2 reduction in solutions of hexafluorophosphate salts of the general formula X+ PF6-, where, X = tetra butyl ammonium (TBA), K, Na and Li, in acetonitrile have been studied on glassy carbon electrodes using cyclic voltammetry (CV) and rotating disk electrode (RDE) techniques. Our results show that cation choice strongly influences the reduction mechanism of O2. Electrochemical data supports the view that alkali metal oxides formed via electrochemical and chemical reactions passivate the electrode surface inhibiting the kinetics and reversibility of the processes. The O2 reduction mechanisms in the presence of the different cations have been supplemented by kinetic parameters determined from detailed analyses of the CV and RDE data. The organic solvent present in the Li+-conducting electrolyte has a major role on the reversibility of each of the O2 reduction products as found from the work discussed in the next chapter. A fundamental study of the influence of solvents on the oxygen reduction reaction (ORR) in a variety of non-aqueous electrolytes was conducted in chapter 4. In this work special attention was paid to elucidate the mechanism of the oxygen electrode processes in the rechargeable Li-air

  18. Antioxidants Keep the Potentially Probiotic but Highly Oxygen-Sensitive Human Gut Bacterium Faecalibacterium prausnitzii Alive at Ambient Air

    PubMed Central

    Khan, M. Tanweer; van Dijl, Jan Maarten; Harmsen, Hermie J. M.

    2014-01-01

    The beneficial human gut microbe Faecalibacterium prausnitzii is a ‘probiotic of the future’ since it produces high amounts of butyrate and anti-inflammatory compounds. However, this bacterium is highly oxygen-senstive, making it notoriously difficult to cultivate and preserve. This has so far precluded its clinical application in the treatment of patients with inflammatory bowel diseases. The present studies were therefore aimed at developing a strategy to keep F. prausnitzii alive at ambient air. Our previous research showed that F. prausnitzii can survive in moderately oxygenized environments like the gut mucosa by transfer of electrons to oxygen. For this purpose, the bacterium exploits extracellular antioxidants, such as riboflavin and cysteine, that are abundantly present in the gut. We therefore tested to what extent these antioxidants can sustain the viability of F. prausnitzii at ambient air. The present results show that cysteine can facilitate the survival of F. prausnitzii upon exposure to air, and that this effect is significantly enhanced the by addition of riboflavin and the cryoprotectant inulin. The highly oxygen-sensitive gut bacterium F. prausnitzii can be kept alive at ambient air for 24 h when formulated with the antioxidants cysteine and riboflavin plus the cryoprotectant inulin. Improved formulations were obtained by addition of the bulking agents corn starch and wheat bran. Our present findings pave the way towards the biomedical exploitation of F. prausnitzii in redox-based therapeutics for treatment of dysbiosis-related inflammatory disorders of the human gut. PMID:24798051

  19. Formation of Nano-Bacteria-Like Flow Textures Formed at Oxygen-Rich Air Condition of Shock Wave Reaction

    NASA Astrophysics Data System (ADS)

    Miura, Y.; Tanosaki, T.

    2011-03-01

    Nano-flow textures with irregular shapes are obtained by shock impact on carbon-fibers with oxygen-rich air condition (not at vacuum condition), which are different with nano-bacteria texture of the martian meteorite with regular nano-flow textures.

  20. Two-photon absorption laser induced fluorescence measurement of atomic oxygen density in an atmospheric pressure air plasma jet

    NASA Astrophysics Data System (ADS)

    Conway, J.; Gogna, G. S.; Gaman, C.; Turner, M. M.; Daniels, S.

    2016-08-01

    Atomic oxygen number density [O] is measured in an air atmospheric pressure plasma jet (APPJ) using two-photon absorption laser induced fluorescence (TALIF). Gas flow is fixed at 8 slpm, the RF power coupled into the plasma jet varied between 5 W and 20 W, and the resulting changes in atomic oxygen density measured. Photolysis of molecular oxygen is employed to allow in situ calibration of the TALIF system. During calibration, O2 photo-dissociation and two-photon excitation of the resulting oxygen atoms are achieved within the same laser pulse. The atomic oxygen density produced by photolysis is time varying and spatially non-uniform which needs to be corrected for to calibrate the TALIF system for measurement of atomic oxygen density in plasma. Knowledge of the laser pulse intensity I 0(t), wavelength, and focal spot size allows correction factors to be determined using a rate equation model. Atomic oxygen is used for calibration and measurement, so the laser intensity can be increased outside the TALIF quadratic laser power dependence region without affecting the calibration reliability as the laser power dependence will still be the same for both. The atomic O density results obtained are not directly benchmarked against other known density measurement techniques. The results show that the plasma jet atomic oxygen content increases as the RF power coupled into the plasma increases.

  1. Massive Systemic Air Embolism during Extracorporeal Membrane Oxygenation Support of a Neonate with Acute Respiratory Distress Syndrome after Cardiac Surgery

    PubMed Central

    Timpa, Joseph G.; O’Meara, Carlisle; McILwain, R. Britt; Dabal, Robert J.; Alten, Jeffrey A.

    2011-01-01

    Abstract: Extracorporeal membrane oxygenation (ECMO) is universally accepted as a potential lifesaving therapy for neonates suffering severe cardiorespiratory failure, with survival reported as 81% weaning off ECMO and 69% to hospital discharge in this population. Although ECMO may reduce mortality in certain neonatal patients, it is associated with significant complications. Air in the circuit complicates 4.9% of neonatal ECMO runs, and it is crucial that all ECMO caregivers are trained in the prevention of air embolism and possess the knowledge necessary to efficiently identify and remove air from the ECMO circuit to prevent life threatening consequences. We present a fatal case of neonatal systemic air embolism leading to massive entrainment of air into the ECMO venous return cannula of a neonatal patient with acute respiratory distress syndrome following repair of obstructed total anomalous pulmonary venous connection. We describe the pathophysiology and presentation of this rare condition and the importance of early recognition, due to its high mortality rate. PMID:21848179

  2. Chemical exposure-response relationship between air pollutants and reactive oxygen species in the human respiratory tract.

    PubMed

    Lakey, Pascale S J; Berkemeier, Thomas; Tong, Haijie; Arangio, Andrea M; Lucas, Kurt; Pöschl, Ulrich; Shiraiwa, Manabu

    2016-01-01

    Air pollution can cause oxidative stress and adverse health effects such as asthma and other respiratory diseases, but the underlying chemical processes are not well characterized. Here we present chemical exposure-response relations between ambient concentrations of air pollutants and the production rates and concentrations of reactive oxygen species (ROS) in the epithelial lining fluid (ELF) of the human respiratory tract. In highly polluted environments, fine particulate matter (PM2.5) containing redox-active transition metals, quinones, and secondary organic aerosols can increase ROS concentrations in the ELF to levels characteristic for respiratory diseases. Ambient ozone readily saturates the ELF and can enhance oxidative stress by depleting antioxidants and surfactants. Chemical exposure-response relations provide a quantitative basis for assessing the relative importance of specific air pollutants in different regions of the world, showing that aerosol-induced epithelial ROS levels in polluted megacity air can be several orders of magnitude higher than in pristine rainforest air. PMID:27605301

  3. Chemical exposure-response relationship between air pollutants and reactive oxygen species in the human respiratory tract

    PubMed Central

    Lakey, Pascale S. J.; Berkemeier, Thomas; Tong, Haijie; Arangio, Andrea M.; Lucas, Kurt; Pöschl, Ulrich; Shiraiwa, Manabu

    2016-01-01

    Air pollution can cause oxidative stress and adverse health effects such as asthma and other respiratory diseases, but the underlying chemical processes are not well characterized. Here we present chemical exposure-response relations between ambient concentrations of air pollutants and the production rates and concentrations of reactive oxygen species (ROS) in the epithelial lining fluid (ELF) of the human respiratory tract. In highly polluted environments, fine particulate matter (PM2.5) containing redox-active transition metals, quinones, and secondary organic aerosols can increase ROS concentrations in the ELF to levels characteristic for respiratory diseases. Ambient ozone readily saturates the ELF and can enhance oxidative stress by depleting antioxidants and surfactants. Chemical exposure-response relations provide a quantitative basis for assessing the relative importance of specific air pollutants in different regions of the world, showing that aerosol-induced epithelial ROS levels in polluted megacity air can be several orders of magnitude higher than in pristine rainforest air. PMID:27605301

  4. Low temperature, atmospheric pressure, direct current microplasma jet operated in air, nitrogen and oxygen

    NASA Astrophysics Data System (ADS)

    Mohamed, A.-A. H.; Kolb, J. F.; Schoenbach, K. H.

    2010-12-01

    Micro-plasma jets in atmospheric pressure molecular gases (nitrogen, oxygen, air) were generated by blowing these gases through direct current microhollow cathode discharges (MHCDs). The tapered discharge channel, drilled through two 100 to 200 μm thick molybdenum electrodes separated by a 200 μm thick alumina layer, is 150 to 450 μm in diameter in the cathode and has an opening of 100 to 300 μm in diameter in the anode. Sustaining voltages are 400 to 600 V, the maximum current is 25 mA. The gas temperature of the microplasma inside the microhollow cathode varies between ~2000 K and ~1000 K depending on current, gas, and flow rate. Outside the discharge channel the temperature in the jet can be reduced by manipulating the discharge current and the gas flow to achieve values close to room temperature. This cold microplasma jet can be used for surface treatment of heat sensitive substances, and for sterilization of contaminated areas.

  5. Unique erosion features of hafnium cathode in atmospheric pressure arcs of air, nitrogen and oxygen

    NASA Astrophysics Data System (ADS)

    Ghorui, S.; Meher, K. C.; Kar, R.; Tiwari, N.; Sahasrabudhe, S. N.

    2016-07-01

    Experimental investigation of cathode erosion in atmospheric pressure hafnium-electrode plasma torches is reported under different plasma environments along with the results of numerical simulation. Air, nitrogen and oxygen are the plasma gases considered. Distinct differences in the erosion features in different plasmas are brought out. Cathode images exhibiting a degree of erosion and measured erosion rates are presented in detail as a function of time of arc operation and arc current. Physical erosion rates are determined using high precision balance. The changes in the surface microstructures are investigated through scanning electron microscopy (SEM). Evolution of cathode chemistry is determined using energy dispersive x-ray spectroscopy (EDX). Numerical simulation with proper consideration of the plasma effects is performed for all the plasma gases. The important role of electromagnetic body forces in shaping the flow field and the distribution of pressure in the region is explored. It is shown that the mutual interaction between fluid dynamic and electromagnetic body forces may self-consistently evolve a situation of an extremely low cathode erosion rate.

  6. Increased stability toward oxygen reduction products for lithium-air batteries with oligoether-functionalized silane electrolytes.

    SciTech Connect

    Zhang, Z.; Lu, J.; Assary, R. S.; Du, P.; Wang, H-H.; Sun, Y-K.; Qin, Y.; Lau, K. C.; Greeley, J.; Redfern, P. C.; Iddir, H.; Curtiss, L. A.; Amine, K.

    2011-01-01

    The successful development of Li-air batteries would significantly increase the possibility of extending the range of electric vehicles. There is much evidence that typical organic carbonate based electrolytes used in lithium ion batteries form lithium carbonates from reaction with oxygen reduction products during discharge in lithium-air cells so more stable electrolytes need to be found. This combined experimental and computational study of an electrolyte based on a tri(ethylene glycol)-substituted trimethylsilane (1NM3) provides evidence that the ethers are more stable toward oxygen reduction discharge species. X-ray photoelectron spectroscopy (XPS) and FTIR experiments show that only lithium oxides and no carbonates are formed when 1NM3 electrolyte is used. In contrast XPS shows that propylene carbonate (PC) in the same cell configuration decomposes to form lithium carbonates during discharge. Density functional calculations of probable decomposition reaction pathways involving solvated oxygen reduction species confirm that oligoether substituted silanes, as well as other ethers, are more stable to the oxygen reduction products than propylene carbonate. These results indicate that the choice of electrolyte plays a key role in the performance of Li-air batteries.

  7. Increased Stability Toward Oxygen Reduction Products for Lithium-Air Batteries with Oligoether-Functionalized Silane Electrolytes

    SciTech Connect

    Zhang, Zhengcheng; Lu, Jun; Assary, Rajeev S.; Du, Peng; Wang, Hsien-Hau; Sun, Yang-Kook; Qin, Yan; Lau, Kah Chun; Greeley, Jeffrey P.; Redfern, Paul C.; Iddir, Hakim; Curtiss, Larry A.; Amine, Khalil

    2011-12-29

    The successful development of Li-air batteries would significantly increase the possibility of extending the range of electric vehicles. There is much evidence that typical organic carbonate based electrolytes used in lithium ion batteries form lithium carbonates from reaction with oxygen reduction products during discharge in lithium-air cells so more stable electrolytes need to be found. This combined experimental and computational study of an electrolyte based on a tri(ethylene glycol)-substituted trimethylsilane (1NM3) provides evidence that the ethers are more stable toward oxygen reduction discharge species. X-ray photoelectron spectroscopy (XPS) and FTIR experiments show that only lithium oxides and no carbonates are formed when 1NM3 electrolyte is used. In contrast XPS shows that propylene carbonate (PC) in the same cell configuration decomposes to form lithium carbonates during discharge. Density functional calculations of probable decomposition reaction pathways involving solvated oxygen reduction species confirm that oligoether substituted silanes, as well as other ethers, are more stable to the oxygen reduction products than propylene carbonate. These results indicate that the choice of electrolyte plays a key role in the performance of Li-air batteries.

  8. Organic carbonyl compounds in Albuquerque, New Mexico, air: A preliminary study of the effects of oxygenated fuel use

    SciTech Connect

    Popp, C.J.; Zhang, Lin; Gaffney, J.S.

    1993-06-01

    A suite of inorganic and organic species were analyzed for four 2--4 day time periods over a year in Albuquerque, New Mexico to determine baseline conditions for organic pollutants under the current air pollution control parameters. Concentrations of low molecular weight carbonyl compounds were relatively high compared with areas such as Los Angeles. Formio acid concentrations in air samples were significant even in winter. In addition, ratios of peroxypropionyl nitrate to peroxyacyetyl nitrate are higher than expected and may be related to the use of oxygenated fuels which are used to mitigate CO concentrations. The number of CO violations in Albuquerque has decreased steadily since 1982 and the downward trend has continued since 1989 when oxygenated fuel use was mandated. It is, therefore, difficult to correlate the drop in CO violations directly to the use of oxygenated fuels when such factors as fleet turnover, woodburning controls, emissions testing and meteorological conditions also may be playing significant roles. More detailed studies are needed to determine the specific relationship between the use of oxygenated fuels and the air quality in Albuquerque, New Mexico and similar urban areas in the western United States.

  9. Enhanced performance of an air-cathode microbial fuel cell with oxygen supply from an externally connected algal bioreactor.

    PubMed

    Kakarla, Ramesh; Kim, Jung Rae; Jeon, Byong-Hun; Min, Booki

    2015-11-01

    An algae bioreactor (ABR) was externally connected to air-cathode microbial fuel cells (MFCs) to increase power generation by supplying a high amount of oxygen to cathode electrode. The MFC with oxygen fed from ABR produced maximum cell voltage and cathode potential at a fixed loading of 459 mV and 10 mV, respectively. During polarization analysis, the MFC displayed a maximum power density of 0.63 W/m(2) (at 2.06 A/m(2)) using 39.2% O2 from ABR, which was approximately 30% higher compared with use of atmospheric air (0.44 W/m(2), 20.8% O2,). The cyclic voltammogram analysis exhibited a higher reduction current of -137 mA with 46.5% O2 compared to atmospheric air (-115 mA). Oxygen supply by algae bioreactor to air-cathode MFC could also maintain better MFC performance in long term operation by minimizing cathode potential drop over time. PMID:26188984

  10. The effectiveness of circulating aeration in air and high purity oxygen systems for control of VOC emissions from aeration basins

    SciTech Connect

    Zhu, H.; Keener, T.C.; Bishop, P.L.; Orton, T.L.; Wang, M.; Siddiqui, K.F.

    1997-12-31

    A simple steady state circulating aeration system (CAS) model has been used to study the effects of volatility and degradability on the fate of VOCs in both air and high purity oxygen (HPO) systems. With increase of circulation ratio in an air CAS, air emissions by stripping can be significantly reduced for compounds of low degradabilities and high volatilities. Enhancement of biodegradation is more significant for compounds of high degradabilities and volatilities. A large portion of VOCs will remain in the wastewater when circulation ratio is high, especially for VOCs that are difficult to degrade. In HPO systems, emissions by stripping are much less than air systems. However, VOCs will remain in the wastewater if they have poor degradabilities. Volatilities of VOCs are not important in HPO systems. Due to their wide range and large uncertainties, degradation rate constants are a major factor determining the effectiveness of a CAS for VOC emission control

  11. Oxygen-Concentrating Cell

    NASA Technical Reports Server (NTRS)

    Buehler, K.

    1986-01-01

    High-purity oxygen produced from breathing air or from propellantgrade oxygen in oxygen-concentrating cell. Operating economics of concentrator attractive: Energy consumption about 4 Wh per liter of oxygen, slightly lower than conventional electrochemical oxygen extractors.

  12. Performance of a hydrogen burner to simulate air entering scramjet combustors. [simulation of total temperature, total pressure, and volume fraction of oxygen of air at flight conditions

    NASA Technical Reports Server (NTRS)

    Russin, W. R.

    1974-01-01

    Tests were conducted to determine the performance of a hydrogen burner used to produce a test gas that simulates air entering a scramjet combustor at various flight conditions. The test gas simulates air in that it duplicates the total temperature, total pressure, and the volume fraction of oxygen of air at flight conditions. The main objective of the tests was to determine the performance of the burner as a function of the effective exhaust port area. The conclusions were: (1) pressure oscillations of the chugging type were reduced in amplitude to plus or minus 2 percent of the mean pressure level by proper sizing of hydrogen, oxygen, and air injector flow areas; (2) combustion efficiency remained essentially constant as the exhaust port area was increased by a factor of 3.4; (3) the mean total temperature determined from integrating the exit radial gas property profiles was within plus or minus 5 percent of the theoretical bulk total temperature; (4) the measured exit total temperature profile had a local peak temperature more than 30 percent greater than the theoretical bulk total temperature; and (5) measured heat transfer to the burner liner was 75 percent of that predicted by theory based on a flat radial temperature profile.

  13. Melting of corrosion-resisting steels using air in bath agitation at the end of oxygen blowing

    NASA Astrophysics Data System (ADS)

    Gizatulin, R. A.; Valuev, D. V.; Valueva, A. V.; Yedesheva, Ch V.

    2014-10-01

    A number of metallurgical plants employ ladle stirring with argon at the end of oxygen blowing during the melting process of corrosion-resisting steels [1, 2]. At the same time, the scarcity and relatively high cost of argon, its low pressure in a shop air pipeline restrain most plants from using argon for corrosion-resisting steel production. Compressed air was used instead of argon to intensify the process of decarbonizing when chromium-nickel stainless steels were made with a 40-ton electric arc furnace at the Kuznetsk Metallurgical Plant.

  14. Nitrogen, oxygen and air broadened widths and relative intensities of N2O lines near 2450/cm

    NASA Technical Reports Server (NTRS)

    Hawkins, R. L.

    1982-01-01

    Spectra of the v sub 1 + 2v sub 2 and the weak underlying v sub 1 + 3v sub 2 - v sub 2 band of N2O near 2450/cm were analyzed by the nonlinear, least squares, whole band technique. The oxygen, nitrogen, and air broadened line widths and the relative line intensities were determined. The air broadened widths, for/m/3, are in agreement with those in the 1980 AFGL line listing and the relative band intensities also agree, within about 20% with the values in this listing.

  15. Water-vapor line broadening and shifting by air, nitrogen, oxygen, and argon in the 720-nm wavelength region

    NASA Technical Reports Server (NTRS)

    Grossmann, Benoist E.; Browell, Edward V.

    1989-01-01

    High-resolution spectroscopic measurements of H2O vapor in the 720-nm wavelength region were conducted to investigate the broadening and shifting of H2O lines by air, nitrogen, oxygen, and argon over a wide range of pressures and temperatures. For each of the buffer gases under study, a linear relationship was found between the widths and the shifts, with the broader lines having the smaller pressure shifts. The pressure shifts measured compared favorably with theoretical values reported by Bykov et al. (1988). The temperature-dependence exponents for air-broadening were found to be J-dependent, with the lower-J lines having the higher exponents.

  16. On the influence of singlet oxygen molecules on the speed of flame propagation in methane-air mixture

    SciTech Connect

    Starik, A.M.; Kozlov, V.E.; Titova, N.S.

    2010-02-15

    The effect of the presence of singlet oxygen molecules O{sub 2}(a{sup 1}{delta}{sub g}) in a CH{sub 4}-air mixture on the speed of laminar flame propagation is considered. The known experimental data on the laminar flame speed and ignition delay are used to validate the developed kinetic model involving electronically excited oxygen molecules O{sub 2}(a{sup 1}{delta}{sub g}) and O{sub 2}(b{sup 1}{sigma}{sub g}{sup +}). Numerical simulation shows that the presence of 10% O{sub 2}(a{sup 1}{delta}{sub g}) in molecular oxygen enables to increase significantly (by a factor of 1.7) the speed of flame propagation in a fuel-lean ({phi}=0.45) methane-air mixture. The main reason for such an acceleration of flame propagation is the intensification of chain reactions due to addition of singlet delta oxygen molecules. For a fuel-rich mixture ({phi}=1.9), the growth in the flame speed is significantly smaller and attains a factor of 1.4. (author)

  17. The amphibious fish Kryptolebias marmoratus uses different strategies to maintain oxygen delivery during aquatic hypoxia and air exposure.

    PubMed

    Turko, Andy J; Robertson, Cayleih E; Bianchini, Kristin; Freeman, Megan; Wright, Patricia A

    2014-11-15

    Despite the abundance of oxygen in atmospheric air relative to water, the initial loss of respiratory surface area and accumulation of carbon dioxide in the blood of amphibious fishes during emersion may result in hypoxemia. Given that the ability to respond to low oxygen conditions predates the vertebrate invasion of land, we hypothesized that amphibious fishes maintain O2 uptake and transport while emersed by mounting a co-opted hypoxia response. We acclimated the amphibious fish Kryptolebias marmoratus, which are able to remain active for weeks in both air and water, for 7 days to normoxic brackish water (15‰, ~21kPa O2; control), aquatic hypoxia (~3.6kPa), normoxic air (~21 kPa) or aerial hypoxia (~13.6kPa). Angiogenesis in the skin and bucco-opercular chamber was pronounced in air- versus water-acclimated fish, but not in response to hypoxia. Aquatic hypoxia increased the O2-carrying capacity of blood via a large (40%) increase in red blood cell density and a small increase in the affinity of hemoglobin for O2 (P50 decreased 11%). In contrast, air exposure increased the hemoglobin O2 affinity (decreased P50) by 25% without affecting the number of red blood cells. Acclimation to aerial hypoxia both increased the O2-carrying capacity and decreased the hemoglobin O2 affinity. These results suggest that O2 transport is regulated both by O2 availability and also, independently, by air exposure. The ability of the hematological system to respond to air exposure independent of O2 availability may allow extant amphibious fishes, and may also have allowed primitive tetrapods to cope with the complex challenges of aerial respiration during the invasion of land. PMID:25267849

  18. Polycyclic aromatic hydrocarbon (PAH) and oxygenated PAH (OPAH) air-water exchange during the deepwater horizon oil spill.

    PubMed

    Tidwell, Lane G; Allan, Sarah E; O'Connell, Steven G; Hobbie, Kevin A; Smith, Brian W; Anderson, Kim A

    2015-01-01

    Passive sampling devices were used to measure air vapor and water dissolved phase concentrations of 33 polycyclic aromatic hydrocarbons (PAHs) and 22 oxygenated PAHs (OPAHs) at four Gulf of Mexico coastal sites prior to, during, and after shoreline oiling from the Deepwater Horizon oil spill (DWH). Measurements were taken at each site over a 13 month period, and flux across the water-air boundary was determined. This is the first report of vapor phase and flux of both PAHs and OPAHs during the DWH. Vapor phase sum PAH and OPAH concentrations ranged between 1 and 24 ng/m(3) and 0.3 and 27 ng/m(3), respectively. PAH and OPAH concentrations in air exhibited different spatial and temporal trends than in water, and air-water flux of 13 individual PAHs were strongly associated with the DWH incident. The largest PAH volatilizations occurred at the sites in Alabama and Mississippi in the summer, each nominally 10,000 ng/m(2)/day. Acenaphthene was the PAH with the highest observed volatilization rate of 6800 ng/m(2)/day in September 2010. This work represents additional evidence of the DWH incident contributing to air contamination, and provides one of the first quantitative air-water chemical flux determinations with passive sampling technology. PMID:25412353

  19. Gas turbine engine adapted for use in combination with an apparatus for separating a portion of oxygen from compressed air

    DOEpatents

    Bland, Robert J.; Horazak, Dennis A.

    2012-03-06

    A gas turbine engine is provided comprising an outer shell, a compressor assembly, at least one combustor assembly, a turbine assembly and duct structure. The outer shell includes a compressor section, a combustor section, an intermediate section and a turbine section. The intermediate section includes at least one first opening and at least one second opening. The compressor assembly is located in the compressor section to define with the compressor section a compressor apparatus to compress air. The at least one combustor assembly is coupled to the combustor section to define with the combustor section a combustor apparatus. The turbine assembly is located in the turbine section to define with the turbine section a turbine apparatus. The duct structure is coupled to the intermediate section to receive at least a portion of the compressed air from the compressor apparatus through the at least one first opening in the intermediate section, pass the compressed air to an apparatus for separating a portion of oxygen from the compressed air to produced vitiated compressed air and return the vitiated compressed air to the intermediate section via the at least one second opening in the intermediate section.

  20. 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 ...

  1. Alterations in resting oxygen consumption in women exposed to 10 days of cold air

    SciTech Connect

    Armstrong, D.W.; Thomas, J.R. )

    1991-03-11

    Repeated exposure to cold air reduces the metabolic response to cold air exposure in man. The purpose of this investigation was to measure the change in resting metabolic rate (RMR) with exposure to 22C air and 4C air during a 12 day period. Four women sat in 22C air for 45 min followed by 45 min in 4C air each day for ten days. The authors measured RMR during a 45 min period in 22C air followed by 45 min in 4C air on four days. All subjects began their morning exposures on a Monday within 2 days of the onset of menses completing the study on a Friday, 12 days later. Subjects dressed in a T-shirt, shorts and cotton socks. During 45 min of exposure to warm air, RMR remained steady at 10% of VO{sub 2peak} on Day 1 and 10% on Day 5. RMR during exposure to warm air significantly increased to 13% of VO{sub 2peak} on Day 8 and remained elevated at 13% on Day 12. During exposure to cold air RMR peaked at 31% of CO{sub 2peak} by the 5th min on Day 1. Peak RMR on Day 5 was significantly lower. Pea RMR in the cold remained lower on Days 8 and 12. During cold exposure RMR peaked and then declined to steady-state during min 15 to 45. Steady-state RMR during cold exposure was significantly lower on Day 5, Day 7 and Day 12 when compared to the 23% of VO{sub 2peak} on Day 1. The authors found that RMR in cold air is significantly attenuated by Day 5 and remains lower through Day 12. RMR during warm air exposure is elevated 3% by Day 8 after five (5) days of repeated cold exposure followed by two (2) days without exposure to cold air, and RMR remains elevated on Day 12.

  2. Creep-to-rupture of the steel P92 at 650 °C in oxygen-controlled stagnant lead in comparison to air

    NASA Astrophysics Data System (ADS)

    Yurechko, Mariya; Schroer, Carsten; Skrypnik, Aleksandr; Wedemeyer, Olaf; Konys, Jürgen

    2013-01-01

    Creep-to-rupture experiments were performed on 9%-Cr ferritic-martensitic steel P92 in the CRISLA facility. The specimens of P92 were examined at 650 °C and static tensile stress between 75 and 325 MPa in both stagnant lead with 10-6 mass% dissolved oxygen and air. The steel showed an insignificant difference in time-to-rupture, tR, and ductile fracture in both environments at >100 MPa, corresponding to tR < 3,442 h. At 75 MPa in Pb (tR = 13,090 h), the steel, however, featured purely brittle fracture pointing to liquid metal embrittlement. Structural changes in the steel and surface oxidation in the different environments were studied using metallographic techniques. The Laves phase that forms during thermal aging at 650 °C was found along prior austenite grain boundaries and martensite laths already after relatively short testing time, along with chromium carbides that are already present in the as-received condition of the steel.

  3. Gas sensing in microplates with optodes: influence of oxygen exchange between sample, air, and plate material.

    PubMed

    Arain, Sarina; Weiss, Svenja; Heinzle, Elmar; John, Gernot T; Krause, Christian; Klimant, Ingo

    2005-05-01

    Microplates with integrated optical oxygen sensors are a new tool to study metabolic rates and enzyme activities. Precise measurements are possible only if oxygen exchange between the sample and the environment is known. In this study we quantify gas exchange in plastic microplates. Dissolved oxygen was detected using either an oxygen-sensitive film fixed at the bottom of each well or a needle-type sensor. The diffusion of oxygen into wells sealed with different foils, paraffin oil, and paraffin wax, respectively, was quantified. Although foil covers showed the lowest oxygen permeability, they include an inevitable gas phase between sample and sealing and are difficult to manage. The use of oil was found to be critical due to the extensive shaking caused by movement of the plates during measurements in microplate readers. Thus, paraffin wax was the choice material because it avoids convection of the sample and is easy to handle. Furthermore, without shaking, significant gradients in pO2 levels within a single well of a polystyrene microplate covered with paraffin oil were detected with the needle-type sensor. Higher pO2 levels were obtained near the surface of the sample as well as near the wall of the well. A significant diffusion of oxygen through the plastic plate material was found using plates based on polystyrene. Thus, the location of a sensor element within the well has an effect on the measured pO2 level. Using a sensor film fixed on the bottom of a well or using a dissolved pO2-sensitive indicator results in pO2 offset and in apparently lower respiration rates or enzyme activities. Oxygen diffusion through a polystyrene microplate was simulated for measurements without convection--that is, for samples without oxygen diffusion through the cover and for unshaken measurements using permeable sealings. This mathematical model allows for calculation of the correct kinetic parameters. PMID:15772950

  4. Histochemical and functional improvement of adipose-derived stem cell-based tissue-engineered cartilage by hyperbaric oxygen/air treatment in a rabbit articular defect model.

    PubMed

    Dai, Niann-Tzyy; Fan, Gang-Yi; Liou, Nien-Hsien; Wang, Yi-Wen; Fu, Keng-Yen; Ma, Kuo-Hsing; Liu, Jiang-Chuan; Chang, Shun-Cheng; Huang, Kun-Lun; Dai, Lien-Guo; Chen, Shyi-Gen; Chen, Tim-Mo

    2015-05-01

    Cartilage is exposed to compression forces during joint loading. Therefore, exogenous stimuli are frequently used in cartilage tissue engineering strategies to enhance chondrocyte differentiation and extracellular matrix (ECM) secretion. In this study, human adipose-derived stem cells were seeded on a gelatin/polycaprolactone scaffold to evaluate the histochemical and functional improvement of tissue-engineered cartilage after hyperbaric oxygen/air treatment in a rabbit articular defect model. Behavior tests showed beneficial effects on weight-bearing and rear leg-supporting capacities after treatment of tissue-engineered cartilage with 2.5 ATA oxygen or air. Moreover, positron emission tomography images and immunohistochemistry staining demonstrated hydroxyapatite formation and increased ECM synthesis, respectively, at the tissue-engineered cartilage graft site after high pressure oxygen/air treatment. Based on these results, we concluded that hyperbaric oxygen and air treatment can improve the quality of tissue-engineered cartilage in vivo by increasing the synthesis of ECM. PMID:25695443

  5. 3D Ordered Mesoporous Bifunctional Oxygen Catalyst for Electrically Rechargeable Zinc-Air Batteries.

    PubMed

    Park, Moon Gyu; Lee, Dong Un; Seo, Min Ho; Cano, Zachary Paul; Chen, Zhongwei

    2016-05-01

    To enhance energy efficiency and durability, a highly active and durable 3D ordered mesoporous cobalt oxide framework has been developed for rechargeable zinc-air batteries. The bifunctional air electrode consisting of 3DOM Co3 O4 having high active surface area and robust structure, results in superior charge and discharge battery voltages, and durable performance for electrically rechargeable zinc-air batteries. PMID:27043451

  6. Analytical chemical kinetic investigation of the effects of oxygen, hydrogen, and hydroxyl radicals on hydrogen-air combustion

    NASA Technical Reports Server (NTRS)

    Carson, G. T., Jr.

    1974-01-01

    Quantitative values were computed which show the effects of the presence of small amounts of oxygen, hydrogen, and hydroxyl radicals on the finite-rate chemical kinetics of premixed hydrogen-air mixtures undergoing isobaric autoignition and combustion. The free radicals were considered to be initially present in hydrogen-air mixtures at equivalence ratios of 0.2, 0.6, 1.0, and 1.2. Initial mixture temperatures were 1100 K, 1200 K, and 1500 K, and pressures were 0.5, 1.0, 2.0, and 4.0 atm. Of the radicals investigated, atomic oxygen was found to be the most effective for reducing induction time, defined as the time to 5 percent of the total combustion temperature rise. The reaction time, the time between 5 percent and 95 percent of the temperature rise, is not decreased by the presence of free radicals in the initial hydrogen-air mixture. Fuel additives which yield free radicals might be used to effect a compact supersonic combustor design for efficient operation in an otherwise reaction-limited combustion regime.

  7. Technology of oxygen production in the membranecryogenic air separation system for a 600 MW oxy-type pulverized bed boiler

    NASA Astrophysics Data System (ADS)

    Berdowska, Sylwia; Skorek-Osikowska, Anna

    2012-09-01

    In this paper the results of the thermodynamic analysis of the oxy-combustion type pulverized bed boiler integrated with a hybrid, membrane- cryogenic oxygen separation installation are presented. For the calculations a 600 MW boiler with live steam parameters at 31.1 MPa /654.9 oC and reheated steam at 6.15 MPa/672.4 oC was chosen. In this paper the hybrid membrane-cryogenic technology as oxygen production unit for pulverized bed boiler was proposed. Such an installation consists of a membrane module and two cryogenic distillation columns. Models of these installations were built in the Aspen software. The energy intensity of the oxygen production process in the hybrid system was compared with the cryogenic technology. The analysis of the influence of membrane surface area on the energy intensity of the process of air separation as well as the influence of oxygen concentration at the inlet to the cryogenic installation on the energy intensity of a hybrid unit was performed.

  8. The diluter-demand oxygen system used during the international Himalayan expedition to Mount Everest.

    NASA Technical Reports Server (NTRS)

    Blume, F. D.; Pace, N.

    1972-01-01

    The diluter-demand regulators are designed in such a way that as the individual inspires he simultaneously draws ambient air and pure oxygen from a tank into his mask. The size of the ambient air orifice is made directly proportional to the barometric pressure by use of a passive aneroid valve. As altitude increases the ambient air orifice is automatically made smaller and the individual inspires a greater proportion of oxygen.

  9. Enriched-air and oxygen gasification of Illinois No. 6 coal in a Texaco coal-gasification unit

    SciTech Connect

    Crouch, W.B.; Richter, G.N.; Dillingham, E.W.

    1982-02-01

    Four runs were made with Illinois No. 6 coal, from Peabody Coal Company River King Mine at Freeburg, Illinois, to demonstrate technology to integrate the Texaco Coal Gasification Process in an environmentally acceptable manner with gas turbines for combined cycle electric power generation. Operability and response of the gasifier and a Selexol acid gas removal unit were demonstrated during load changes utilizing both oxygen and enriched air as oxidants (transient runs). Steady state performance data on the gasifier, Selexol unit and gas turbine combustor were obtained at a variety of oxygen to coal ratios at different production rates utilizing each oxidant (steady state runs). Essentially no effect of charge rate on the syngas quality was noted. Environmental base line data were gathered for both oxidants. Results of the environmental tests and the turbine combustor tests are reported separately.

  10. First-principles study of the oxygen evolution reaction of lithium peroxide in the lithium-air battery

    NASA Astrophysics Data System (ADS)

    Mo, Yifei; Ong, Shyue Ping; Ceder, Gerbrand

    2011-11-01

    The lithium-air chemistry is an interesting candidate for the next-generation batteries with high specific energy. However, this new battery technology is facing substantial challenges, such as a high overpotential upon charging, poor reversibility, and low power density. Using first-principles calculations, we study the oxygen evolution reaction (OER) on the low-index surfaces of lithium peroxide. The elementary reaction steps and the energy profile of the OER are identified on the low-index surfaces of lithium peroxide. We find that the OER processes are kinetically limited by the high energy barrier for the evolution of oxygen molecules and that the rate of the OER processes is highly dependent on the surface orientation.

  11. Effects of Hyperbaric Oxygen at 1.25 Atmospheres Absolute with Normal Air on Macrophage Number and Infiltration during Rat Skeletal Muscle Regeneration

    PubMed Central

    Fujita, Naoto; Ono, Miharu; Tomioka, Tomoka; Deie, Masataka

    2014-01-01

    Use of mild hyperbaric oxygen less than 2 atmospheres absolute (2026.54 hPa) with normal air is emerging as a common complementary treatment for severe muscle injury. Although hyperbaric oxygen at over 2 atmospheres absolute with 100% O2 promotes healing of skeletal muscle injury, it is not clear whether mild hyperbaric oxygen is equally effective. The purpose of the present study was to investigate the impact of hyperbaric oxygen at 1.25 atmospheres absolute (1266.59 hPa) with normal air on muscle regeneration. The tibialis anterior muscle of male Wistar rats was injured by injection of bupivacaine hydrochloride, and rats were randomly assigned to a hyperbaric oxygen experimental group or to a non-hyperbaric oxygen control group. Immediately after the injection, rats were exposed to hyperbaric oxygen, and the treatment was continued for 28 days. The cross-sectional area of centrally nucleated muscle fibers was significantly larger in rats exposed to hyperbaric oxygen than in controls 5 and 7 days after injury. The number of CD68- or CD68- and CD206-positive cells was significantly higher in rats exposed to hyperbaric oxygen than in controls 24 h after injury. Additionally, tumor necrosis factor-α and interleukin-10 mRNA expression levels were significantly higher in rats exposed to hyperbaric oxygen than in controls 24 h after injury. The number of Pax7- and MyoD- or MyoD- and myogenin-positive nuclei per mm2 and the expression levels of these proteins were significantly higher in rats exposed to hyperbaric oxygen than in controls 5 days after injury. These results suggest that mild hyperbaric oxygen promotes skeletal muscle regeneration in the early phase after injury, possibly due to reduced hypoxic conditions leading to accelerated macrophage infiltration and phenotype transition. In conclusion, mild hyperbaric oxygen less than 2 atmospheres absolute with normal air is an appropriate support therapy for severe muscle injuries. PMID:25531909

  12. Investigation into the optoelectrical properties of tungsten oxide thin films annealed in an oxygen air

    SciTech Connect

    Arfaoui, A.; Ouni, B. Touihri, S.; Mannoubi, T.

    2014-12-15

    Tungsten oxide (WO{sub x}) thin film have been deposited onto glass substrates using the thermal vacuum evaporation technique, monitored by an annealing process in a variable oxygen atmosphere. Analysis by X-ray diffraction and Raman spectroscopy showed the structural changes from orthorhombic to monoclinic which depend on the annealing temperature and the oxygen content. AFM study shows that the increase of oxygen content leads to a decrease of the root-mean-square from 94.64 nm to 2 nm. Ellipsometric measurements have been used to evaluate the optical constants. Further, it is found that when the oxygen content increases, the band gap of the annealed layer varies from 3.01 eV to 3.52 eV by against, the Urbach energy decreases. The AC conductivity plot showed a universal power law according to the Jonscher model. Moreover, at high frequency semiconductor-to-metallic behavior has been observed. Finally, the effect of annealing in oxygen atmosphere on their structural modifications, morphological, optical properties and electrical conductivity are reported.

  13. Penguin lungs and air sacs: implications for baroprotection, oxygen stores and buoyancy.

    PubMed

    Ponganis, P J; St Leger, J; Scadeng, M

    2015-03-01

    The anatomy and volume of the penguin respiratory system contribute significantly to pulmonary baroprotection, the body O2 store, buoyancy and hence the overall diving physiology of penguins. Therefore, three-dimensional reconstructions from computerized tomographic (CT) scans of live penguins were utilized to measure lung volumes, air sac volumes, tracheobronchial volumes and total body volumes at different inflation pressures in three species with different dive capacities [Adélie (Pygoscelis adeliae), king (Aptenodytes patagonicus) and emperor (A. forsteri) penguins]. Lung volumes scaled to body mass according to published avian allometrics. Air sac volumes at 30 cm H2O (2.94 kPa) inflation pressure, the assumed maximum volume possible prior to deep dives, were two to three times allometric air sac predictions and also two to three times previously determined end-of-dive total air volumes. Although it is unknown whether penguins inhale to such high volumes prior to dives, these values were supported by (a) body density/buoyancy calculations, (b) prior air volume measurements in free-diving ducks and (c) previous suggestions that penguins may exhale air prior to the final portions of deep dives. Based upon air capillary volumes, parabronchial volumes and tracheobronchial volumes estimated from the measured lung/airway volumes and the only available morphometry study of a penguin lung, the presumed maximum air sac volumes resulted in air sac volume to air capillary/parabronchial/tracheobronchial volume ratios that were not large enough to prevent barotrauma to the non-collapsing, rigid air capillaries during the deepest dives of all three species, and during many routine dives of king and emperor penguins. We conclude that volume reduction of airways and lung air spaces, via compression, constriction or blood engorgement, must occur to provide pulmonary baroprotection at depth. It is also possible that relative air capillary and parabronchial volumes are

  14. Oxygenation of intensive cell-culture system.

    PubMed

    Emery, A N; Jan, D C; al-Rubeai, M

    1995-11-01

    The abilities of various methods of oxygenation to meet the demands of high-cell-density culture were investigated using a spin filter perfusion system in a bench-top bioreactor. Oxygen demand at high cell density could not be met by sparging with air inside a spin filter (oxygen transfer values in this condition were comparable with those for surface aeration). Sparging with air outside a spin filter gave adequate oxygen transfer for the support of cell concentrations above 10(7) ml-1 in fully aerobic conditions but the addition of antifoam to control foaming caused blockage of the spinfilter mesh. Bubble-free aeration through immersed silicone tubing with pure oxygen gave similar oxygen transfer rates to that of sparging with air but without the problems of bubble damage and fouling of the spin filter. A supra-optimal level of dissolved oxygen (478% air saturation) inhibited cell growth. However, cells could recover from this stress and reach high density after reduction of the dissolved oxygen level to 50% air saturation. PMID:8590652

  15. Cooling rates of living and killed chicken and quail eggs in air and in helium-oxygen gas mixture.

    PubMed

    Tazawa, H; Turner, J S; Paganelli, C V

    1988-01-01

    1. In a helium atmosphere, heat is dissipated from a surface 3.5 times faster than it is in air. Eggs in a helium-oxygen atmosphere cool only 1.4 times faster than they cool in air. This signifies that internal resistance to heat flow is a significant factor in the cooling rates of eggs. 2. Heat flow occurs inside an egg in two ways: by conduction through the tissues and in flowing blood. Killing an embryo stops the latter, but not the former. Eggs cool more slowly after they have been killed, signifying that blood flow can be an important component in an egg's internal flows of heat. 3. Blood flow should be a relatively more important component of heat flow in large eggs than in small eggs. The difference in conductance between living and killed eggs is larger in 60 g chicken eggs than it is in 10 g quail eggs. PMID:2900113

  16. Experimental evaluation of oxygen-enriched air and emulsified fuels in a single-cylinder diesel engine

    SciTech Connect

    Sekar, R.R.; Marr, W.W.; Cole, R.L.; Marciniak, T.J.

    1991-11-01

    The performance of a single-cylinder, direct-injection diesel engine was measured with intake oxygen levels of up to 35% and fuel water contents of up to 20%. Because a previous study indicated that the use of a less-expensive fuel would be more economical, two series of tests with No. 4 diesel fuel and No. 2 diesel fuel were conducted. To control the emissions of nitrogen oxides (NO{sub x}), water was introduced into the combustion process in the form of water-emulsified fuel, or the fuel injection timing was retarded. In the first series of tests, compressed oxygen was used; in the second series of tests, a hollow-tube membrane was used. Steady-state engine performance and emissions data were obtained. Test results indicated a large increase in engine power density, a slight improvement in thermal efficiency, and significant reductions in smoke and particulate-matter emissions. Although NO{sub x} emissions increased, they could be controlled by introducing water and retarding the injection timing. The results further indicated that thermal efficiency is slightly increased when moderately water-emulsified fuels are used, because a greater portion of the fuel energy is released earlier in the combustion process. Oxygen-enriched air reduced the ignition delay and caused the heat-release rate and cumulative heat-release rates to change measurably. Even at higher oxygen levels, NO{sub x} emissions decreased rapidly when the timing was retarded, and the amount of smoke and the level of particulate-matter emissions did not significantly increase. The single-cylinder engine tests confirmed the results of an earlier technical assessment and further indicated a need for a low-pressure-drop membrane specifically designed for oxygen enrichment. Extension data set indexed separately. 14 refs.

  17. A system for the disposal of large volumes of air containing oxygen-15

    NASA Astrophysics Data System (ADS)

    Peters, J. M.; Quaglia, L.; del Fiore, G.; Hannay, J.; Fissore, A.

    1991-01-01

    A method is described which permits large volumes of air containing the radionuclide 15O to be vented into the atmosphere. The short half-life of this isotope (124 s) enables use to be made of a large number of small vessels connected in series. Such a device has the effect of increasing the mean transit time. The system as installed results in a reduction of the radioactive concentration in the vented air to levels below the maximum permitted values.

  18. Thermodynamic Properties of Air and Mixtures of Nitrogen, Argon, and Oxygen From 60 to 2000 K at Pressures to 2000 MPa

    NASA Astrophysics Data System (ADS)

    Lemmon, Eric W.; Jacobsen, Richard T.; Penoncello, Steven G.; Friend, Daniel G.

    2000-05-01

    A thermodynamic property formulation for standard dry air based upon available experimental p-ρ-T, heat capacity, speed of sound, and vapor-liquid equilibrium data is presented. This formulation is valid for liquid, vapor, and supercritical air at temperatures from the solidification point on the bubble-point curve (59.75 K) to 2000 K at pressures up to 2000 MPa. In the absence of reliable experimental data for air above 873 K and 70 MPa, air properties were predicted from nitrogen data in this region. These values were included in the determination of the formulation to extend the range of validity. Experimental shock tube measurements on air give an indication of the extrapolation behavior of the equation of state up to temperatures and pressures of 5000 K and 28 GPa. The available measurements of thermodynamic properties of air are summarized and analyzed. Separate ancillary equations for the calculation of dew and bubble-point pressures and densities of air are presented. In the range from the solidification point to 873 K at pressures to 70 MPa, the estimated uncertainty of density values calculated with the equation of state is 0.1%. The estimated uncertainty of calculated speed of sound values is 0.2% and that for calculated heat capacities is 1%. At temperatures above 873 K and 70 MPa, the estimated uncertainty of calculated density values is 0.5% increasing to 1.0% at 2000 K and 2000 MPa. In addition to the equation of state for standard air, a mixture model explicit in Helmholtz energy has been developed which is capable of calculating the thermodynamic properties of mixtures containing nitrogen, argon, and oxygen. This model is valid for temperatures from the solidification point on the bubble-point curve to 1000 K at pressures up to 100 MPa over all compositions. The Helmholtz energy of the mixture is the sum of the ideal gas contribution, the real gas contribution, and the contribution from mixing. The contribution from mixing is given by a single

  19. Co3O4 nanoparticle-modified MnO2 nanotube bifunctional oxygen cathode catalysts for rechargeable zinc-air batteries

    NASA Astrophysics Data System (ADS)

    Du, Guojun; Liu, Xiaogang; Zong, Yun; Hor, T. S. Andy; Yu, Aishui; Liu, Zhaolin

    2013-05-01

    We report the preparation of MnO2 nanotubes functionalized with Co3O4 nanoparticles and their use as bifunctional air cathode catalysts for oxygen reduction reaction and oxygen evolution reaction in rechargeable zinc-air batteries. These hybrid MnO2/Co3O4 nanomaterials exhibit enhanced catalytic reactivity toward oxygen evolution reaction under alkaline conditions compared with that in the presence of MnO2 nanotubes or Co3O4 nanoparticles alone.We report the preparation of MnO2 nanotubes functionalized with Co3O4 nanoparticles and their use as bifunctional air cathode catalysts for oxygen reduction reaction and oxygen evolution reaction in rechargeable zinc-air batteries. These hybrid MnO2/Co3O4 nanomaterials exhibit enhanced catalytic reactivity toward oxygen evolution reaction under alkaline conditions compared with that in the presence of MnO2 nanotubes or Co3O4 nanoparticles alone. Electronic supplementary information (ESI) available: Zinc-air cell device, XPS survey scan and power density of the cell. See DOI: 10.1039/c3nr00300k

  20. The effect of irradiation in air or in hyperbaric oxygen on the Fib/T tumor in WHT mice pretreated with a hypoxic gas mixture

    SciTech Connect

    Hendrikse, A.; Blekkenhorst, G. )

    1991-01-01

    The effect of exposing WHT mice bearing the Fib/T tumor to a low-oxygen environment (8, 10, and 15% oxygen) for 48 h or 72 h before irradiation was compared, using an in vitro colony-forming excision assay, to the effect obtained when mice were pretreated with air. The response of the Fib/T tumor to radiation delivered in air was improved both by a 48-h and by a 72-h exposure of the animals to 8, 10, and 15% oxygen. However, the greatest tumor sensitization was achieved when mice were kept in 8% oxygen for 48 h before irradiation. These results are interpreted and discussed in relation to increases in the 2,3-DPG concentration, which were shown to occur when mice were exposed to a reduced oxygen environment. The relative importance of two models proposed to explain these findings is assessed. If mice pretreated with air were irradiated in hyperbaric oxygen, a similar tumor response was observed compared to that when mice were exposed to 8% oxygen for 48 h and then irradiated in air.

  1. Study of using oxygen-enriched combustion air for locomotive diesel engines

    SciTech Connect

    Poola, R.B.; Sekar, R.; Assanis, D.N.; Cataldi, G.R.

    1996-10-01

    A thermodynamic simulation is used to study effects of O2-enriched intake air on performance and NO emissions of a locomotive diesel engine. Parasitic power of the air separation membrane required to supply the O2-enriched air is also estimated. For a given constraint on peak cylinder pressure, gross and net power output of an engine operating under different levels of O2 enrichment are compared with those obtained when a high-boost turbocharged engine is used. A 4% increase in peak cylinder pressure can result in 13% increase in net engine power when intake air with 28 vol% O2 is used and fuel injection timing retarded by 4 degrees. When the engine is turbocharged to a higher inlet boost, the same increase in peak cylinder pressure can result in only 4% improvement in power. If part of the higher exhaust enthalpies from the O2 enrichment is recovered, the power requirements of the air separator membrane can be met. O2 enrichment with its higher combustion temperatures reduces emissions of particulates and visible smoke but increases NO emissions (by up to 3 times at 26% O2 content). Therefore, exhaust gas after-treatment and heat recovery would be required if the full potential of O2 enrichment for improving the performance of locomotive diesel engines is to be realized.

  2. Out of thin air: Sensory detection of oxygen and carbon dioxide

    PubMed Central

    Scott, Kristin

    2011-01-01

    Oxygen and carbon dioxide levels vary in different environments and locally fluctuate during respiration and photosynthesis. Recent studies in diverse animals have identified sensory neurons that detect these external variations and direct a variety of behaviors. Detection allows animals to stay within a preferred environment as well as identify potential food or dangers. The complexity of sensation is reflected in the fact that neurons compartmentalize detection into increases, decreases, short-range and long-range cues. Animals also adjust their responses to these prevalent signals in context of other cues, allowing for flexible behaviors. In general, the molecular mechanisms for detection suggest that sensory neurons adopted ancient strategies for cellular detection and coupled them to brain activity and behavior. This review highlights the multiple strategies that animals use to extract information about their environment from variations in oxygen and carbon dioxide. PMID:21262460

  3. Economic Evaluations of Energy Recovery options for oxygen- and enriched air-blown Texaco GCC power plants. Final report

    SciTech Connect

    Beckman, R.F.; Coleman, B.S.; Dawkins, R.P.; Rao, A.D.; Ravikumar, R.H.; Smelser, S.C.; Stock, R.M.

    1980-11-01

    This report presents the results of preliminary process design and economic screening studies of seven integrated Texaco-based coal gasification/combined-cycle power plant systems. Previous reports have indicated that the oxidant feed and hot gasifier effluent cooling units are the most costly items in the gasification system and, thus, hold the greatest possibility of being reduced. Therefore, the systems examined reflect combinations of two types of coal oxidant (98 percent oxygen and enriched air containing 35 percent oxygen) and four gas cooling options. Also presented is an eighth process design (without economics) of the most efficient of the seven systems under the more favorable ISO ambient conditions, rather than summer conditions. Except for the gasifiers and associated high-temperature heat recovery equipment, all of the combined-cycle designs in this report use commercially available components, including the gas turbines. The gasifier performances are based on extrapolations of the pilot plant gasifiers from mid- to the late 1980s. The high-temperature heat recovery equipment designs have not been demonstrated as full-sized equipment. The first and major objective was to determine whether or not oxygen-blown Texaco-based gasification combined-cycle power plants employing current technology combustion turbine (2000/sup 0/F), could produce electricity at a competitive cost to that produced in a conventional coal-fired steam plant using limestone scrubbers for SO/sub 2/ removal. When all the cases are compared and referred to earlier studies, it is concluded that oxygen-blown Texaco GCC plants employing current technology (2000/sup 0/F) combustion turbines produce electricity that is cost competitive with electricity produced by a conventional coal-fired steam plant with stack gas scrubbers designed to meet 1978 New Source Performance Standards.

  4. Air-Sea Exchange and Budget of Sulfur and Oxygen-Containing Volatile Organic Compounds in the Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Tanimoto, H.; Omori, Y.; Inomata, S.; Iwata, T.; Kameyama, S.

    2015-12-01

    By combining proton transfer reaction-mass spectrometry (PTR-MS) and gradient flux (GF) technique, in situ measurement of air-sea fluxes of multiple volatile organic compounds (VOCs) was developed and deployed. Starting in 2008, we made in situ observations of air-sea fluxes at 15 locations as well as underway observations of marine air/surface seawater bulk concentrations in the Pacific Ocean, during eight research cruises by R/V Hakuho-Maru. The fluxes of biogenic trace gases, DMS and isoprene, were always positive, with the magnitudes being in accordance with previously reported. In contrast, the fluxes of oxygenated VOCs including acetone and acetaldehyde varied from negative to positive, suggesting that the tropical and subtropical Pacific are a source, while the North Pacific is a sink. A basin-scale budget of VOCs were determined for 4 biogeochemical provinces in the Pacific Ocean, and the role of oceans for VOCs were discussed with respect to physical and biogeochemical processes.

  5. Performance of MnO2 Crystallographic Phases in Rechargeable Lithium-Air Oxygen Cathode

    NASA Astrophysics Data System (ADS)

    Oloniyo, Olubukun; Kumar, Senthil; Scott, Keith

    2012-05-01

    Manganese dioxide (MnO2) has been shown to be effective for improving the efficiency of cathodes in lithium-air cells. Different crystallographic phases including α-, β-, and γ-MnO2 nanowires, α-MnO2 nanospheres, and α-MnO2 nanowires on carbon ( α-MnO2/C) were synthesized using the hydrothermal method. Their physical properties were examined using x-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area measurements, and scanning electron microscopy (SEM) and found to be in agreement with the literature. Electrochemical properties of the synthesized catalyst particles were investigated by fabricating cathodes and testing them in a lithium-air cell with lithium hexafluorophosphate in propylene carbonate (LiPF6/PC) and tetra(ethylene glycol)dimethyl ether (LiTFSi/TEGDME) electrolytes. α-MnO2 had the highest discharge capacity in the LiTFSi/TEGDME electrolyte (2500 mAh/g), whilst α-MnO2/C in LiPF6/PC showed a significantly higher discharge capacity of 11,000 mAh/g based on total mass of the catalytic cathode. However, the latter showed poor capacity retention compared with γ-MnO2 nanowires, which was stable for up to 30 cycles. The reported discharge capacity is higher than recorded in previous studies on lithium-air cells.

  6. Cortical Air Spaces (Aerenchyma) in Roots of Corn Subjected to Oxygen Stress

    PubMed Central

    Drew, Malcolm C.; Chamel, André; Garrec, Jean-Paul; Fourcy, André

    1980-01-01

    When the seminal root system of 14-day-old corn (Zea mays cv. Dekalb 202) was subjected to O2 stress, nodal roots with well developed cortical air spaces (aerenchyma) grew into the deoxygenated solution. Microscopic examination showed that there was extensive breakdown of cells in the midcortex of these roots, while the stele, endodermis, and inner layer of cortical cells remained complete, as did the outer layers of the cortex and the epidermis. Occasional files of intact cells, and the wall residues of collapsed cells, crossed the space between inner and outer cortex. Experiments with short, intact root segments with and without air spaces showed that in the presence of O2 the ability to absorb and translocate 86Rb+, per unit volume or length of root, was little affected by cortical degeneration. The distribution across root sections of recently supplied strontium and rubidium, determined by electron microprobe analysis, indicated that in roots with air spaces the strands of wall residues bridging the cortex could be involved in maintaining the conduction of ions from the outer cortex up to the endodermis. Images PMID:16661224

  7. Oxygen intake in track and treadmill running with observations on the effect of air resistance

    PubMed Central

    Pugh, L. G. C. E.

    1970-01-01

    1. The relation of V̇O2 and speed was measured on seven athletes running on a cinder track and an all-weather track. The results were compared with similar observations on four athletes running on a treadmill. 2. In treadmill running the relation was linear and the zero intercept coincided with resting V̇O2. 3. In track running the relation was curvilinear, but was adequately represented by a linear regression over a range of speeds extending from 8·0 km/hr (2·2 m/sec) to 21·5 km/hr (6·0 m/sec). The slope of this line was substantially steeper than the regression line slope for treadmill running. 4. The influence of air resistance in running was estimated from measurements of V̇O2 on a subject running on a treadmill at constant speed against wind of varying velocity. 5. The extra O2 intake (ΔV̇O2) associated with wind increased as the square of wind velocity. If wind velocity and running velocity are equal, as in running on a track in calm air, ΔV̇O2 will increase as the cube of velocity. 6. It was estimated that the energy cost of overcoming air resistance in track running is about 8% of total energy cost at 21·5 km/hr (5000 m races) and 16% for sprinting 100 m in 10·0 sec. ImagesFig. 4 PMID:5532903

  8. Impairment of Venous Drainage on Extracorporeal Membrane Oxygenation Secondary to Air Trapping in Acute Asphyxial Asthma.

    PubMed

    Niimi, Kevin S; Lewis, Leslie S; Fanning, Jeffrey J

    2015-06-01

    The inability to adequately support a patient on extracorporeal membrane oxygenation (ECMO) due to impaired drainage is not an uncommon occurrence during support. Typically, the causes include hypovolemia, kinks in the circuit, cannula malposition, or inadequate cannula size. In this report we present an uncommon etiology of this problem. A 3-year-old female presented to our hospital in status asthmaticus and pulseless electrical activity (PEA). This was a result of dynamic hyperinflation of the lungs causing physical obstruction of venous return to the heart. Upon initiating venoarterial (VA) ECMO, we experienced inadequate drainage that did not improve despite multiple interventions. This resolved with the addition of an inhaled anesthetic gas to treat this patient's severe bronchospasm. This case illustrates the importance of considering a patient's physiology or disease state and how that may affect the mechanics of ECMO support. PMID:26405359

  9. On the effect of pressure, oxygen concentration, air flow and gravity on simulated pool fires

    NASA Technical Reports Server (NTRS)

    Torero, J. L.; Most, J. M.; Joulain, P.

    1995-01-01

    The initial development of a fire is characterized by the establishment of a diffusion flame over the surface of a the condensed fuel and is particularly influenced by gravity, with most of the gaseous flow induced by natural convection. Low initial momentum of the fuel vapor, strong buoyant flows induced by the hot post-combustion gases and consequently low values of the Froude number (inertia-gravity forces ratio) are typical of this kind of scenario. An experimental study is conducted by using a porous burner to simulate the burning of a horizontal combustible surface. Ethane is used as fuel and different mixtures of oxygen and nitrogen as oxidizer. The magnitude of the fuel injection velocities is restricted to values that will keep the Froude number on the order of 10-5, when calculated at normal gravity and pressure, which are characteristic of condensed fuel burning. Two different burners are used, a circular burner (62 mm diameter) placed inside a cylindrical chamber (0.3 m diameter and 1.0 m height) and a rectangular burner (50 mm wide by 200 mm long) placed in a wind tunnel (350 mm long) of rectangular cross section (120 mm wide and 90 mm height). The first burner is used to study the effect of pressure and gravity in the absence of a forced flow parallel to the surface. The second burner is used to study the effect of a forced flow parallel to the burner surface as well as the effect of oxygen concentration in the oxidizer flow. In this case experiments are also conducted at different gravity levels (micro-gravity, 0.2 g(sub 0), g(sub 0) and 1.8 g(sub 0)) to quantify the relative importance of buoyancy.

  10. Experimental study on transmission of an overdriven detonation wave from propane/oxygen to propane/air

    SciTech Connect

    Li, J.; Lai, W.H.; Chung, K.; Lu, F.K.

    2008-08-15

    Two sets of experiments were performed to achieve a strong overdriven state in a weaker mixture by propagating an overdriven detonation wave via a deflagration-to-detonation transition (DDT) process. First, preliminary experiments with a propane/oxygen mixture were used to evaluate the attenuation of the overdriven detonation wave in the DDT process. Next, experiments were performed wherein a propane/oxygen mixture was separated from a propane/air mixture by a thin diaphragm to observe the transmission of an overdriven detonation wave. Based on the characteristic relations, a simple wave intersection model was used to calculate the state of the transmitted detonation wave. The results showed that a rarefaction effect must be included to ensure that there is no overestimate of the post-transmission wave properties when the incident detonation wave is overdriven. The strength of the incident overdriven detonation wave plays an important role in the wave transmission process. The experimental results showed that a transmitted overdriven detonation wave occurs instantaneously with a strong incident overdriven detonation wave. The near-CJ state of the incident wave leads to a transmitted shock wave, and then the transition to the overdriven detonation wave occurs downstream. The attenuation process for the overdriven detonation wave decaying to a near-CJ state occurs in all tests. After the attenuation process, an unstable detonation wave was observed in most tests. This may be attributed to the increase in the cell width in the attenuation process that exceeds the detonability cell width limit. (author)

  11. Relating surface chemistry and oxygen surface exchange in LnBaCo2O(5+δ) air electrodes.

    PubMed

    Téllez, Helena; Druce, John; Kilner, John A; Ishihara, Tatsumi

    2015-01-01

    The surface and near-surface chemical composition of electroceramic materials often shows significant deviations from that of the bulk. In particular, layered materials, such as cation-ordered LnBaCo2O(5+δ) perovskites (Ln = lanthanide), undergo surface and sub-surface restructuring due to the segregation of the divalent alkaline-earth cation. These processes can take place during synthesis and processing steps (e.g. deposition, sintering or annealing), as well as at temperatures relevant for the operation of these materials as air electrodes in solid oxide fuel cells and electrolysers. Furthermore, the surface segregation in these double perovskites shows fast kinetics, starting at temperatures as low as 400 °C over short periods of time and leading to a decrease in the transition metal surface coverage exposed to the gas phase. In this work, we use a combination of stable isotope tracer labeling and surface-sensitive ion beam techniques to study the oxygen transport properties and their relationship with the surface chemistry in ordered LnBaCo2O(5+δ) perovskites. Time-of-Flight Secondary-Ion Mass Spectrometry (ToF-SIMS) combined with (18)O isotope exchange was used to determine the oxygen tracer diffusion (D*) and surface exchange (k*) coefficients. Furthermore, Low Energy Ion Scattering (LEIS) was used for the analysis of the surface and near surface chemistry as it provides information from the first mono-atomic layer of the materials. In this way, we could relate the compositional modifications (e.g. cation segregation) taking place at the electrochemically-active surface during the exchange at high temperatures and the oxygen transport properties in double perovskite electrode materials to further our understanding of the mechanism of the surface exchange process. PMID:26212446

  12. Creep-to-rupture of 9%Cr steel T91 in air and oxygen-controlled lead at 650 °C

    NASA Astrophysics Data System (ADS)

    Yurechko, Mariya; Schroer, Carsten; Wedemeyer, Olaf; Skrypnik, Aleksandr; Konys, Jürgen

    2011-12-01

    This article reports results of uniaxial creep-to-rupture experiments at static loads ranging from 100 to 200 MPa on ferritic-martensitic steel T91 in stagnant lead at 650 °C and oxygen concentration co in a narrow range around 10 -6 mass%. Respective experiments in stagnant air have been performed for comparison. The steel showed almost no difference in creep performance in oxygen-controlled lead and air at 650 °C. No dissolution attack and no lead penetration were found on the steel.

  13. Formation of reactive oxygen and nitrogen species by repetitive negatively pulsed helium atmospheric pressure plasma jets propagating into humid air

    NASA Astrophysics Data System (ADS)

    Norberg, Seth A.; Johnsen, Eric; Kushner, Mark J.

    2015-06-01

    Atmospheric pressure plasma jets have many beneficial effects in their use in surface treatment and, in particular, plasma medicine. One of these benefits is the controlled production of reactive oxygen and nitrogen species (RONS) in the active discharge through the molecular gases added to the primary noble gas in the input mixture, and through the interaction of reactive species in the plasma effluent with the ambient air. In this computational investigation, a parametric study was performed on the production of RONS in a multiply pulsed atmospheric pressure plasma jet sustained in a He/O2 mixture and flowing into ambient humid air. The consequences of flow rate, O2 fraction, voltage, and repetition rate on reactant densities after a single discharge pulse, after 30 pulses, and after the same total elapsed time were investigated. At the end of the first discharge pulse, voltage has the greatest influence on RONS production. However, the systematic trends for production of RONS depend on repetition rate and flow rate in large part due to the residence time of RONS in the plasma zone. Short residence times result in reactive species produced by the previous pulse still being in the discharge tube or in the path of the ionization wave at the next pulse. The RONS therefore accumulate in the tube and in the near effluent on a pulse-to-pulse basis. This accumulation enables species requiring multiple reactions among the primary RONS species to be produced in greater numbers.

  14. Integrated turbomachine oxygen plant

    DOEpatents

    Anand, Ashok Kumar; DePuy, Richard Anthony; Muthaiah, Veerappan

    2014-06-17

    An integrated turbomachine oxygen plant includes a turbomachine and an air separation unit. One or more compressor pathways flow compressed air from a compressor through one or more of a combustor and a turbine expander to cool the combustor and/or the turbine expander. An air separation unit is operably connected to the one or more compressor pathways and is configured to separate the compressed air into oxygen and oxygen-depleted air. A method of air separation in an integrated turbomachine oxygen plant includes compressing a flow of air in a compressor of a turbomachine. The compressed flow of air is flowed through one or more of a combustor and a turbine expander of the turbomachine to cool the combustor and/or the turbine expander. The compressed flow of air is directed to an air separation unit and is separated into oxygen and oxygen-depleted air.

  15. A sensitive LC-MS/MS method for measurement of organophosphorus pesticides and their oxygen analogs in air sampling matrices.

    PubMed

    Armstrong, Jenna L; Dills, Russell L; Yu, Jianbo; Yost, Michael G; Fenske, Richard A

    2014-01-01

    A rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed for determination of levels of the organophosphorus (OP) pesticides chlorpyrifos (CPF), azinphos methyl (AZM), and their oxygen analogs chlorpyrifos-oxon (CPF-O) and azinphos methyl-oxon (AZM-O) on common active air sampling matrices. XAD-2 resin and polyurethane foam (PUF) matrices were extracted with acetonitrile containing stable-isotope labeled internal standards (ISTD). Analysis was accomplished in Multiple Reaction Monitoring (MRM) mode, and analytes in unknown samples were identified by retention time (±0.1 min) and qualifier ratio (±30% absolute) as compared to the mean of calibrants. For all compounds, calibration linearity correlation coefficients were ≥0.996. Limits of detection (LOD) ranged from 0.15-1.1 ng/sample for CPF, CPF-O, AZM, and AZM-O on active sampling matrices. Spiked fortification recoveries were 78-113% from XAD-2 active air sampling tubes and 71-108% from PUF active air sampling tubes. Storage stability tests also yielded recoveries ranging from 74-94% after time periods ranging from 2-10 months. The results demonstrate that LC-MS/MS is a sensitive method for determining these compounds from two different matrices at the low concentrations that can result from spray drift and long range transport in non-target areas following agricultural applications. In an inter-laboratory comparison, the limit of quantification (LOQ) for LC-MS/MS was 100 times lower than a typical gas chromatography-mass spectrometry (GC-MS) method. PMID:24328542

  16. Hyperbaric oxygen therapy

    MedlinePlus

    Hyperbaric oxygen therapy uses a special pressure chamber to increase the amount of oxygen in the blood. ... outpatient centers. The air pressure inside a hyperbaric oxygen chamber is about two and a half times ...

  17. The injection of air/oxygen bubble into the anterior chamber of rabbits as a treatment for hyphema in patients with sickle cell disease.

    PubMed

    Ayintap, Emre; Keskin, Uğurcan; Sadigov, Fariz; Coskun, Mesut; Ilhan, Nilufer; Motor, Sedat; Semiz, Hilal; Parlakfikirer, Nihan

    2014-01-01

    Purpose. To investigate the changes of partial oxygen pressure (PaO2) in aqueous humour after injecting air or oxygen bubble into the anterior chamber in sickle cell hyphema. Methods. Blood samples were taken from the same patient with sickle cell disease. Thirty-two rabbits were divided into 4 groups. In group 1 (n = 8), there was no injection. Only blood injection constituted group 2 (n = 8), both blood and air bubble injection constituted group 3 (n = 8), and both blood and oxygen bubble injection constituted group 4 (n = 8). Results. The PaO2 in the aqueous humour after 10 hours from the injections was 78.45 ± 9.9 mmHg (Mean ± SD) for group 1, 73.97 ± 8.86 mmHg for group 2, 123.35 ± 13.6 mmHg for group 3, and 306.47 ± 16.5 mmHg for group 4. There was statistically significant difference between group 1 and group 2, when compared with group 3 and group 4. Conclusions. PaO2 in aqueous humour was increased after injecting air or oxygen bubble into the anterior chamber. We offer to leave an air bubble in the anterior chamber of patients with sickle cell hemoglobinopathies and hyphema undergoing an anterior chamber washout. PMID:24808955

  18. Continuous measurement of oxygen tensions in the air-breathing organ of Pacific tarpon (Megalops cyprinoides) in relation to aquatic hypoxia and exercise.

    PubMed

    Seymour, Roger S; Farrell, Anthony P; Christian, Keith; Clark, Timothy D; Bennett, Michael B; Wells, Rufus M G; Baldwin, John

    2007-07-01

    The Pacific tarpon is an elopomorph teleost fish with an air-breathing organ (ABO) derived from a physostomous gas bladder. Oxygen partial pressure (PO(2)) in the ABO was measured on juveniles (238 g) with fiber-optic sensors during exposure to selected aquatic PO(2) and swimming speeds. At slow speed (0.65 BL s(-1)), progressive aquatic hypoxia triggered the first breath at a mean PO(2) of 8.3 kPa. Below this, opercular movements declined sharply and visibly ceased in most fish below 6 kPa. At aquatic PO(2) of 6.1 kPa and swimming slowly, mean air-breathing frequency was 0.73 min(-1), ABO PO(2) was 10.9 kPa, breath volume was 23.8 ml kg(-1), rate of oxygen uptake from the ABO was 1.19 ml kg(-1) min(-1), and oxygen uptake per breath was 2.32 ml kg(-1). At the fastest experimental speed (2.4 BL s(-1)) at 6.1 kPa, ABO oxygen uptake increased to about 1.90 ml kg(-1) min(-1), through a variable combination of breathing frequency and oxygen uptake per breath. In normoxic water, tarpon rarely breathed air and apparently closed down ABO perfusion, indicated by a drop in ABO oxygen uptake rate to about 1% of that in hypoxic water. This occurred at a wide range of ABO PO(2) (1.7-26.4 kPa), suggesting that oxygen level in the ABO was not regulated by intrinsic receptors. PMID:17387483

  19. 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

  20. Twisted partially pure spinors

    NASA Astrophysics Data System (ADS)

    Herrera, Rafael; Tellez, Ivan

    2016-08-01

    Motivated by the relationship between orthogonal complex structures and pure spinors, we define twisted partially pure spinors in order to characterize spinorially subspaces of Euclidean space endowed with a complex structure.

  1. Discharge performance of solid-state oxygen shuttle metal-air battery using Ca-stabilized ZrO2 electrolyte.

    PubMed

    Inoishi, Atsushi; Kim, Hack-Ho; Sakai, Takaaki; Ju, Young-Wan; Ida, Shintaro; Ishihara, Tatsumi

    2015-04-13

    The effects of metal choice on the electrochemical performance of oxygen-shuttle metal-air batteries with Ca-stabilized ZrO2 (CSZ) as the electrolyte and various metals as the anodes were studied at 1073 K. The equilibrium oxygen partial pressure (P O 2) in the anode chamber was governed by the metal used in the anode chamber. A lower-P O 2 environment in the anode decreased the polarization resistance of the anode. The oxidation of oxide ions to oxygen in the anode is drastically enhanced by the n-type conduction generated in the CSZ electrolyte when it is exposed to a reducing atmosphere. A high discharge potential and high capacity can be achieved in an oxygen-shuttle battery with a Li or Mg anode because of the fast anode reaction compared to that of cells with a Zn, Fe, or Sn anode. However, only the mildly reducing metals (Zn, Si, Fe, and Sn) can potentially be used in rechargeable metal-air batteries because the transport number of the CSZ electrolyte must be unity during charge and discharge. Oxygen shuttle rechargeable batteries with Fe, and Sn electrodes are demonstrated. PMID:25727525

  2. Efficiency evaluation of oxygen enrichment in energy conversion processes

    SciTech Connect

    Bomelburg, H.J.

    1983-12-01

    The extent to which energy conversion efficiencies can be increased by using oxygen or oxygen-enriched air for combustion was studied. Combustion of most fuels with oxygen instead of air was found to have five advantages: increases combustion temperature and efficiency, improves heat transfer at high temperatures, reduces nitrous oxide emissions, permits a high ration of exhaust gas recirculation and allows combustion of certain materials not combustible in air. The same advantages, although to a lesser degree, are apparent with oxygen-enriched air. The cost-effectiveness of the process must necessarily be improved by about 10% when using oxygen instead of air before such use could become justifiable on purely economic terms. Although such a modest increase appears to be attainable in real situations, this study ascertained that it is not possible to generally assess the economic gains. Rather, each case requires its own evaluation. For certain processes industry has already proven that the use of oxygen leads to more efficient plant operation. Several ideas for essentially new applications are described. Specifically, when oxygen is used with exhaust gas recirculation in external or internal combustion engines. It appears also that the advantages of pulse combustion can be amplified further if oxygen is used. When burning wet fuels with oxygen, direct steam generation becomes possible. Oxygen combustion could also improve processes for in situ gasification of coals, oil shales, peats, and other wet fuels. Enhanced oil recovery by fire flooding methods might also become more effective if oxygen is used. The cold energy contained in liquid oxygen can be substantially recovered in the low end of certain thermodynamic cycles. Further efforts to develop certain schemes for using oxygen for combustion appear to be justified from both the technical and economic viewpoints.

  3. The relationship between oxygen consumption rate and viability of in vivo-derived pig embryos vitrified by the micro volume air cooling method.

    PubMed

    Sakagami, N; Nishida, K; Misumi, K; Hirayama, Y; Yamashita, S; Hoshi, H; Misawa, H; Akiyama, K; Suzuki, C; Yoshioka, K

    2016-01-01

    The aim of this study was to assess the viability of vitrified-warmed in vivo-derived pig embryos after measuring the oxygen consumption rate. Six days after artificial insemination, blastocysts were collected from gilts and vitrified by the micro volume air cooling method. The oxygen consumption rate was measured in 60 vitrified-warmed embryos, which were then cultured for 48h to assess the viability. The survival (re-expansion) rate of embryos after warming was 85.0%. The average oxygen consumption rate of embryos immediately after warming was greater in embryos which could re-expand during subsequent culture (F=0.75±0.04) than that in those which failed to re-expand (F=0.33±0.05). Moreover, the oxygen consumption rate of vitrified-warmed embryos was greater in the hatched (F=0.88±0.06) than that in the not-hatched group (F=0.53±0.04). When the oxygen consumption rate of the vitrified-warmed embryos and the numbers of viable and dead cells in embryos were determined, there was a positive correlation between the oxygen consumption rate and the number of live cells (P<0.01, r=0.538). A total of 29 vitrified embryos after warming and measuring the oxygen consumption rate were surgically transferred into uterine horns of two recipients. Both of the recipients become pregnant and farrowed 12 healthy piglets. These results demonstrate that the oxygen consumption rate of vitrified-warmed pig embryos can be related to the number of live cells and that the measurement of oxygen consumption of embryos after cryopreservation may be useful for estimating embryo survivability. PMID:26642748

  4. Rotational coherent anti-stokes Raman spectroscopy measurements in a rotating cavity with axial throughflow of cooling air: oxygen concentration measurements.

    PubMed

    Black, J D; Long, C A

    1992-07-20

    In a rotating cavity rig, which models cooling air flow in the spaces between disks of a gas turbine compressor, the buildup of oxygen concentration after the cooling gas was changed from nitrogen to air was monitored using rotational coherent anti-Stokes Raman spectroscopy (CARS). From this information an estimate of the fraction of the throughflow entering the rotating cavity was obtained. This demonstrates that rotational CARS can be applied as a nonintrusive concentration-measurement technique in a rotating engineering test rig. PMID:20725415

  5. Effects of low-pressure air on oxygen contamination and lithium corrosion of a tantalum alloy, T-111, at 980 and 1260 C

    NASA Technical Reports Server (NTRS)

    Gahn, R. F.

    1974-01-01

    The effects were studied of low-pressure air on contamination and corrosion in the tantalum alloy T-111/lithium system at 980 and 1260 C. Capsules of T-111 containing lithium were exposed to six vacuum levels between 1 x 10 to the 8th power and 0.0003 torr by controlled air leakage into a vacuum system. Capsules exposed at 980 C and 0.0002 torr failed from intragranular oxidation. The remainder of the capsules completed the 96-hour tests. The depth of oxygen contamination was greater at 980 C than at 1260 C. Tests made at 0.0001 and 0.00001 torr levels caused large increases in the oxygen content of the T-111. Tests at 0.000001 torr or less produced no significant contamination. No lithium corrosion of the T-111 was observed under any of the conditions.

  6. In situ measurements of change in work function of Pt, Pd and Au surfaces during desorption of oxygen by using photoemission yield spectrometer in air

    NASA Astrophysics Data System (ADS)

    Yamashita, Daisuke; Ishizaki, Atsushi

    2016-02-01

    We investigated the change in work function of Pt, Pd and Au surfaces during desorption of oxygen by using a photoemission yield spectrometer with an open counter. Oxygen coverage was formed by UV/ozone treatment, and then continuous change in work function with exposure to air was observed at various temperatures. Work function of Pt, Pd and Au surfaces decreased during desorption of oxygen, and finally returned to the initial value of untreated surfaces. Furthermore, temperature dependence on the change in work function was found. These characteristics were explained using chemical kinetics scheme. The exponential decay of work function was well reproduced by the first-order reaction rate equation, and it was confirmed that the order of rate constant, kr, is kr(Au) < kr(Pd) < kr(Pt). The activation energy was estimated to be 36, 38 and 28 kJ/mol for Pt, Pd, Au, respectively.

  7. Nickel-Doped La0.8Sr0.2Mn(1-x)Ni(x)O3 Nanoparticles Containing Abundant Oxygen Vacancies as an Optimized Bifunctional Catalyst for Oxygen Cathode in Rechargeable Lithium-Air Batteries.

    PubMed

    Wang, Zhaodong; You, Ya; Yuan, Jing; Yin, Ya-Xia; Li, Yu-Tao; Xin, Sen; Zhang, Dawei

    2016-03-01

    In this work, Ni-doped manganite perovskite oxides (La0.8Sr0.2Mn(1-x)Ni(x)O3, x = 0.2 and 0.4) and undoped La0.8Sr0.2MnO3 were synthesized via a general and facile sol-gel route and used as bifunctional catalysts for oxygen cathode in rechargeable lithium-air batteries. The structural and compositional characterization results showed that the obtained La0.8Sr0.2Mn(1-x)Ni(x)O3 (x = 0.2 and 0.4) contained more oxygen vacancies than did the undoped La0.8Sr0.2MnO3 as well as a certain amount of Ni(3+) (eg = 1) on their surface. The Ni-doped La0.8Sr0.2Mn(1-x)Ni(x)O3 (x = 0.2 and 0.4) was provided with higher bifunctional catalytic activities than that of the undoped La0.8Sr0.2MnO3. In particular, the La0.8Sr0.2Mn0.6Ni0.4O3 had a lower total over potential between the oxygen evolution reaction and the oxygen reduction reaction than that of the La0.8Sr0.2MnO3, and the value is even comparable to that of the commercial Pt/C yet is provided with a much reduced cost. In the lithium-air battery, oxygen cathodes containing the La0.8Sr0.2Mn0.6Ni0.4O3 catalyst delivered the optimized electrochemical performance in terms of specific capacity and cycle life, and a reasonable reaction mechanism was given to explain the improved performance. PMID:26900959

  8. Formation of oxygen vacancies and Ti3+ state in TiO2 thin film and enhanced optical properties by air plasma treatment

    PubMed Central

    Bharti, Bandna; Kumar, Santosh; Lee, Heung-No; Kumar, Rajesh

    2016-01-01

    This is the first time we report that simply air plasma treatment can also enhances the optical absorbance and absorption region of titanium oxide (TiO2) films, while keeping them transparent. TiO2 thin films having moderate doping of Fe and Co exhibit significant enhancement in the aforementioned optical properties upon air plasma treatment. The moderate doping could facilitate the formation of charge trap centers or avoid the formation of charge recombination centers. Variation in surface species viz. Ti3+, Ti4+, O2−, oxygen vacancies, OH group and optical properties was studied using X-ray photon spectroscopy (XPS) and UV-Vis spectroscopy. The air plasma treatment caused enhanced optical absorbance and optical absorption region as revealed by the formation of Ti3+ and oxygen vacancies in the band gap of TiO2 films. The samples were treated in plasma with varying treatment time from 0 to 60 seconds. With the increasing treatment time, Ti3+ and oxygen vacancies increased in the Fe and Co doped TiO2 films leading to increased absorbance; however, the increase in optical absorption region/red shift (from 3.22 to 3.00 eV) was observed in Fe doped TiO2 films, on the contrary Co doped TiO2 films exhibited blue shift (from 3.36 to 3.62 eV) due to Burstein Moss shift. PMID:27572095

  9. Formation of oxygen vacancies and Ti(3+) state in TiO2 thin film and enhanced optical properties by air plasma treatment.

    PubMed

    Bharti, Bandna; Kumar, Santosh; Lee, Heung-No; Kumar, Rajesh

    2016-01-01

    This is the first time we report that simply air plasma treatment can also enhances the optical absorbance and absorption region of titanium oxide (TiO2) films, while keeping them transparent. TiO2 thin films having moderate doping of Fe and Co exhibit significant enhancement in the aforementioned optical properties upon air plasma treatment. The moderate doping could facilitate the formation of charge trap centers or avoid the formation of charge recombination centers. Variation in surface species viz. Ti(3+), Ti(4+), O(2-), oxygen vacancies, OH group and optical properties was studied using X-ray photon spectroscopy (XPS) and UV-Vis spectroscopy. The air plasma treatment caused enhanced optical absorbance and optical absorption region as revealed by the formation of Ti(3+) and oxygen vacancies in the band gap of TiO2 films. The samples were treated in plasma with varying treatment time from 0 to 60 seconds. With the increasing treatment time, Ti(3+) and oxygen vacancies increased in the Fe and Co doped TiO2 films leading to increased absorbance; however, the increase in optical absorption region/red shift (from 3.22 to 3.00 eV) was observed in Fe doped TiO2 films, on the contrary Co doped TiO2 films exhibited blue shift (from 3.36 to 3.62 eV) due to Burstein Moss shift. PMID:27572095

  10. Water Broadening of Oxygen

    NASA Astrophysics Data System (ADS)

    Drouin, Brian J.; Payne, Vivienne; Mlawer, Eli

    2013-06-01

    A need for precise air-mass retrievals utilizing the near-infrared O_2 A-band has motivated measurements of the water-broadening in oxygen. Experimental challenges have resulted in very little water broadened oxygen data, especially in the near-infrared where pressure broadened linewidth must compete with the relatively large thermal linewidth. Existing water broadening data^a for the O_2 A-band is of insufficient precision for application to the atmospheric data. Because of the nature of scattering processes, it is believed that broadening parameters for O_2 from one spectral region may be transferable to other spectral regions - so we investigated the O_2 60 GHz magnetic dipole Q branch which is also used prominently in remote sensing. Atmospheric retrievals of air-mass and temperature that use the 60 GHz magnetic dipole Q branch incorporate a water-broadening parameter that is scaled to self-broadened values, but there is only high temperature data that directly supports this hypothesis.^b We present precise O_2-H_2O broadening measurements for the magnetic dipole Q-branch and the pure-rotational band, measured at room temperature with a Zeeman-modulated absorption cell and a frequency-multiplier spectrometer. Here we will describe the apparatus and the measurement analysis. Inter-comparisons of these and other O_2 broadening data sets confirm the expectation of only minor band-to-band scaling of pressure broadening. The measurement provides a basis for fundamental parameterization of retrieval codes for the long-wavelength atmospheric measurements. Finally, we encourage the application of these measurements for retrievals of air-mass via remote sensing of the oxygen A-band. ^a E.M. Vess et al. J. Phys. Chem. A 116, 4069-4073 (2012). ^b G. Fanjoux et al. J. Chem. Phys. 101(2) 1061-1071 (1994).

  11. Production of Singlet Oxygen within a Flow Discharge

    NASA Astrophysics Data System (ADS)

    Lange, Matthew; Pitz, Greg; Perram, Glen

    2008-10-01

    The Airborne laser program is an Air Force sponsored program to place a laser on the battle field for use as a tactical weapon. The chemical oxygen iodine laser offers the powers necessary for this weapons application, but it requires significant logistical support. The goal of this current research program is to demonstrate an oxygen-iodine laser with electrical discharge production of singlet oxygen. Optical diagnostics have been applied to microwave and radio frequency discharges within a pure oxygen flow. The O2(a) emissions within a discharge are complicated by atomic oxygen emission requiring care in determining gas concentrations from optically measured emissions. Thermal effects also complicate optical emissions. The inclusion of vibrationally excited oxygen as a quencher of the O2(a) state appears to be the limiting rate for production of O2(a) within the electric discharge conditions studied in this research.

  12. 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

  13. 7 CFR 916.16 - Pure grower or pure producer.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Pure grower or pure producer. 916.16 Section 916.16... Order Regulating Handling Definitions § 916.16 Pure grower or pure producer. (a) Pure grower means any...); or (2) Who produces and handles his or her own product; Provided, That a pure grower can pack...

  14. 7 CFR 916.16 - Pure grower or pure producer.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Pure grower or pure producer. 916.16 Section 916.16... Order Regulating Handling Definitions § 916.16 Pure grower or pure producer. (a) Pure grower means any...); or (2) Who produces and handles his or her own product; Provided, That a pure grower can pack...

  15. Quantitative Determination of Density of Ground State Atomic Oxygen from Both TALIF and Emission Spectroscopy in Hot Air Plasma Generated by Microwave Resonant Cavity

    NASA Astrophysics Data System (ADS)

    Marchal, F.; Yousfi, M.; Merbahi, N.; Wattieaux, G.; Piquemal, A.

    2016-03-01

    Two experimental techniques have been used to quantify the atomic oxygen density in the case of hot air plasma generated by a microwave (MW) resonant cavity. The latter operates at a frequency of 2.45 GHz inside a cell of gas conditioning at a pressure of 600 mbar, an injected air flow of 12 L/min and an input MW power of 1 kW. The first technique is based on the standard two photon absorption laser induced fluorescence (TALIF) using xenon for calibration but applied for the first time in the present post discharge hot air plasma column having a temperature of about 4500 K near the axis of the nozzle. The second diagnostic technique is an actinometry method based on optical emission spectroscopy (OES). In this case, we compared the spectra intensities of a specific atomic oxygen line (844 nm) and the closest wavelength xenon line (823 nm). The two lines need to be collected under absolutely the same spectroscopic parameters. The xenon emission is due to the addition of a small proportion of xenon (1% Xe) of this chemically inert gas inside the air while a further small quantity of H2 (2%) is also added in the mixture in order to collect OH(A-X) and NH(A-X) spectra without noise. The latter molecular spectra are required to estimate gas and excitation temperatures. Optical emission spectroscopy measurements, at for instance the position z=12 mm on the axis plasma column that leads to a gas measured temperature equal to 3500 K, an excitation temperature of about 9500 K and an atomic oxygen density 2.09×1017±0.2×1017 cm-3. This is in very good agreement with the TALIF measurement, which is equal to 2.0×1017 cm-3.

  16. In Situ-Grown ZnCo2O4 on Single-Walled Carbon Nanotubes as Air Electrode Materials for Rechargeable Lithium–Oxygen Batteries

    SciTech Connect

    Liu, Bin; Xu, Wu; Yan, Pengfei; Bhattacharya, Priyanka; Cao, Ruiguo; Bowden, Mark E.; Engelhard, Mark H.; Wang, Chong M.; Zhang, Jiguang

    2015-10-12

    Although lithium-oxygen (Li-O2) batteries have great potential to be used as one of the next generation energy storage systems due to their ultrahigh theoretical specific energy, there are still many significant barriers before their practical applications. These barriers include electrolyte and electrode instability, poor ORR/OER efficiency and cycling capability, etc. Development of a highly efficient catalyst will not only enhance ORR/OER efficiency, it may also improve the stability of electrolyte because the reduced charge voltage. Here we report the synthesis of nano-sheet-assembled ZnCo2O4 spheres/single walled carbon nanotubes (ZCO/SWCNTs) composites as high performance air electrode materials for Li-O2 batteries. The ZCO catalyzed SWCNTs electrodes delivered high discharge capacities, decreased the onset of oxygen evolution reaction by 0.9 V during charge processes, and led to more stable cycling stability. These results indicate that ZCO/SWCNTs composite can be used as highly efficient air electrode for oxygen reduction and evolution reactions. The highly enhanced catalytic activity by uniformly dispersed ZnCo2O4 catalyst on nanostructured electrodes is expected to inspire

  17. Demonstration of oxygen-enriched air staging at Owens-Brockway Glass Containers. Technical progress report, August 1, 1995--July 31, 1996

    SciTech Connect

    Rue, D.; Abbasi, H.

    1996-11-01

    The objective of the program is to demonstrate the use of a previously developed combustion modification technology to reduce NO, emissions from sideport regenerative container glass melters. This technology, known as oxygen-enriched air staging (OEAS), has been demonstrated, and is now being commercialized, for endport container glass furnaces. A 17-month development program has been established with specific objectives to: (1) acquire baseline operating data on the host sideport furnace in Vernon, California, (2) evaluate secondary oxidant injection strategies based on earlier endport furnace results and through modeling of a single port pair, (3) retrofit and test one port pair (the test furnace has six port pairs) with a flexible OEAS system, and select the optimal system configuration, (4) use the results from tests with one port pair to design, retrofit, and test OEAS on the entire furnace (six port pairs), and (5) analyze test results, prepare report, and finalize the business plan to commercialize OEAS for sideport furnaces. The host furnace for testing in this program is an Owens-Brockway 6-port pair sideport furnace in Vernon, California producing 325-ton/d of amber container glass. The baseline NO{sub x} level of this optimized furnace is about 4.0 lb/ton of glass. An anticipated NO{sub x}, reduction of 50% will lower the NO{sub x} production level to below 2 lb/ton. Secondary oxidant staging techniques being considered include oxygen-enriched ambient air staging (OEAS) and oxygen staging (OS).

  18. Demonstration of oxygen-enriched air staging at Owens-Brockway glass containers. Quarterly technical progress report, November 1, 1996--January 31, 1997

    SciTech Connect

    Rue, D.; Abbasi, H.

    1997-03-01

    The objective of the program is to demonstrate the use of a previously developed combustion modification technology to reduce NO, emissions from sideport regenerative container glass melters. This technology, known as oxygen-enriched air staging (OEAS), has been demonstrated, and is now being commercialized, for endport container glass furnaces. A 17-month development program has been established with specific objectives to: (1) acquire baseline operating data on the host sideport furnace in Vernon, California, (2) evaluate secondary oxidant injection strategies based on earlier endport furnace results and through modeling of a single port pair, (3) retrofit and test one port pair (the test furnace has six port pairs) with a flexible OEAS system, and select the optimal system configuration, (4) use the results from tests with one port pair to design, retrofit, and test OEAS on the entire furnace (six port pairs), and (5) analyze test results, prepare report, and finalize the business plan to commercialize OEAS for sideport furnaces. The host furnace for testing in this program is an Owens-Brockway 6-port pair sideport furnace in Vernon, California producing 325-ton/d of amber container glass. The baseline NO{sub x} level of this optimized furnace is about 4.0 lb/ton of glass. An anticipated NO{sub x}, reduction of 50% will lower the NO{sub x} production level to below 2 lb/ton. Secondary oxidant staging techniques being considered include oxygen-enriched ambient air staging (OEAS) and oxygen staging (OS).

  19. In Situ-Grown ZnCo2O4 on Single-Walled Carbon Nanotubes as Air Electrode Materials for Rechargeable Lithium-Oxygen Batteries.

    PubMed

    Liu, Bin; Xu, Wu; Yan, Pengfei; Bhattacharya, Priyanka; Cao, Ruiguo; Bowden, Mark E; Engelhard, Mark H; Wang, Chong-Min; Zhang, Ji-Guang

    2015-11-01

    The development of highly efficient catalysts is critical for the practical application of lithium-oxygen (Li-O2) batteries. Nanosheet-assembled ZnCo2O4 (ZCO) microspheres and thin films grown in situ on single-walled carbon nanotube (ZCO/SWCNT) composites as high-performance air electrode materials for Li-O2 batteries are reported. The in situ grown ZCO/SWCNT electrodes delivered high discharge capacities, decreased the onset of the oxygen evolution reaction by 0.9 V during the charging process, and led to longer cycling stability. These results indicate that in situ grown ZCO/SWCNT composites can be used as highly efficient air electrode materials for oxygen reduction and evolution reactions. The enhanced catalytic activity displayed by the uniformly dispersed ZCO catalyst on nanostructured electrodes is expected to inspire further development of other catalyzed electrodes for Li-O2 batteries and other applications. PMID:26457378

  20. Purely lytic osteosarcoma

    SciTech Connect

    De Santos, L.A.; Eideken, B.

    1982-11-01

    The radiographic features of 42 purely lytic osteosarcomas are presented. Purely lytic osteosarcoma is identified as a lytic lesion of bone with no demonstrable osteoid matrix by conventional radiographic modalities. Purely lytic osteosarcoma represented 13.7% of a group of 305 osteosarcomas. The most common presentation was that of a lytic illdefined lesion with a moderate to large extraosseous mass component. Nine lesions presented with benign radiographic features. The differential diagnosis is outlined. The need for awareness of this type of presentation of osteosarcoma is stressed.

  1. Study on the Catalytic Activity of Noble Metal Nanoparticles on Reduced Graphene Oxide for Oxygen Evolution Reactions in Lithium-Air Batteries.

    PubMed

    Jeong, Yo Sub; Park, Jin-Bum; Jung, Hun-Gi; Kim, Jooho; Luo, Xiangyi; Lu, Jun; Curtiss, Larry; Amine, Khalil; Sun, Yang-Kook; Scrosati, Bruno; Lee, Yun Jung

    2015-07-01

    Among many challenges present in Li-air batteries, one of the main reasons of low efficiency is the high charge overpotential due to the slow oxygen evolution reaction (OER). Here, we present systematic evaluation of Pt, Pd, and Ru nanoparticles supported on rGO as OER electrocatalysts in Li-air cell cathodes with LiCF3SO3-tetra(ethylene glycol) dimethyl ether (TEGDME) salt-electrolyte system. All of the noble metals explored could lower the charge overpotentials, and among them, Ru-rGO hybrids exhibited the most stable cycling performance and the lowest charge overpotentials. Role of Ru nanoparticles in boosting oxidation kinetics of the discharge products were investigated. Apparent behavior of Ru nanoparticles was different from the conventional electrocatalysts that lower activation barrier through electron transfer, because the major contribution of Ru nanoparticles in lowering charge overpotential is to control the nature of the discharge products. Ru nanoparticles facilitated thin film-like or nanoparticulate Li2O2 formation during oxygen reduction reaction (ORR), which decomposes at lower potentials during charge, although the conventional role as electrocatalysts during OER cannot be ruled out. Pt-and Pd-rGO hybrids showed fluctuating potential profiles during the cycling. Although Pt- and Pd-rGO decomposed the electrolyte after electrochemical cycling, no electrolyte instability was observed with Ru-rGO hybrids. This study provides the possibility of screening selective electrocatalysts for Li-air cells while maintaining electrolyte stability. PMID:26115340

  2. Gas analysis using Raman spectroscopy demonstrates the presence of intraperitoneal air (nitrogen and oxygen) in a cohort of children undergoing pediatric laparoscopic surgery.

    PubMed

    Taylor, Susan P; Sato, Thomas T; Balcom, Anthony H; Groth, Travis; Hoffman, George M

    2015-02-01

    Clinically significant gas embolism during laparoscopy is a rare but potentially catastrophic event. Case reports suggest that air, in addition to the insufflation gas, may be present. We studied the effects of equipment design and flushing techniques on the composition of gas present under experimental and routine pediatric surgical conditions. Concentrations of nitrogen (N2), oxygen (O2), and carbon dioxide (CO2) were measured by Raman spectroscopy in gas delivered to and retrieved from a mock peritoneum during simulated laparoscopy. We then analyzed the composition of insufflated and recovered gases during elective laparoscopic procedures conducted with CO2-preflushed and unflushed tubing to determine the presence of significant (10%) quantities of air. In vitro, CO2 was not detected at the distal end of insufflator tubing until after delivery of approximately 0.2 L of gas, and N2 persisted until >0.4 L was delivered, with 40% ± 8% (mean ± SD, range 33%-49%) recovered from the mock peritoneum at the termination of initial insufflation. In clinical studies, preflushing reduced the initial concentration of N2 from 78% ± 0.5% to 23% ± 15%, but >10% air was detected in all subsequent samples, regardless of insufflation technique. Laparoscopic equipment and practice routinely permit delivery of air to the insufflated cavity. Purging the equipment with CO2 reduces but does not eliminate air (N2, O2) within the peritoneal cavity during laparoscopy. Thus, when vascular injury occurs, embolized gases will contain variable quantities of N2, O2, and CO2. As the initial insufflation volume diminishes and approaches the volume of the insufflation tubing, which occurs in infants and young pediatric patients, the concentration of N2 will approximate that of room air in an unflushed system. Small insufflation volumes containing high N2 concentrations can contribute to catastrophic air emboli in neonates and small pediatric patients. PMID:25602452

  3. Science: Pure or Applied?

    ERIC Educational Resources Information Center

    Evans, Peter

    1980-01-01

    Through a description of some of the activities which take place in his science classroom, the author makes a strong case for the inclusion of technology, or applied science, rather than pure science in the primary curriculum. (KC)

  4. Pure-quartic solitons.

    PubMed

    Blanco-Redondo, Andrea; de Sterke, C Martijn; Martijn, de Sterke C; Sipe, J E; Krauss, Thomas F; Eggleton, Benjamin J; Husko, Chad

    2016-01-01

    Temporal optical solitons have been the subject of intense research due to their intriguing physics and applications in ultrafast optics and supercontinuum generation. Conventional bright optical solitons result from the interaction of anomalous group-velocity dispersion and self-phase modulation. Here we experimentally demonstrate a class of bright soliton arising purely from the interaction of negative fourth-order dispersion and self-phase modulation, which can occur even for normal group-velocity dispersion. We provide experimental and numerical evidence of shape-preserving propagation and flat temporal phase for the fundamental pure-quartic soliton and periodically modulated propagation for the higher-order pure-quartic solitons. We derive the approximate shape of the fundamental pure-quartic soliton and discover that is surprisingly Gaussian, exhibiting excellent agreement with our experimental observations. Our discovery, enabled by precise dispersion engineering, could find applications in communications, frequency combs and ultrafast lasers. PMID:26822758

  5. Pure-quartic solitons

    PubMed Central

    Blanco-Redondo, Andrea; Martijn, de Sterke C.; Sipe, J.E.; Krauss, Thomas F.; Eggleton, Benjamin J.; Husko, Chad

    2016-01-01

    Temporal optical solitons have been the subject of intense research due to their intriguing physics and applications in ultrafast optics and supercontinuum generation. Conventional bright optical solitons result from the interaction of anomalous group-velocity dispersion and self-phase modulation. Here we experimentally demonstrate a class of bright soliton arising purely from the interaction of negative fourth-order dispersion and self-phase modulation, which can occur even for normal group-velocity dispersion. We provide experimental and numerical evidence of shape-preserving propagation and flat temporal phase for the fundamental pure-quartic soliton and periodically modulated propagation for the higher-order pure-quartic solitons. We derive the approximate shape of the fundamental pure-quartic soliton and discover that is surprisingly Gaussian, exhibiting excellent agreement with our experimental observations. Our discovery, enabled by precise dispersion engineering, could find applications in communications, frequency combs and ultrafast lasers. PMID:26822758

  6. Pure-quartic solitons

    NASA Astrophysics Data System (ADS)

    Blanco-Redondo, Andrea; Martijn, De Sterke C.; Sipe, J. E.; Krauss, Thomas F.; Eggleton, Benjamin J.; Husko, Chad

    2016-01-01

    Temporal optical solitons have been the subject of intense research due to their intriguing physics and applications in ultrafast optics and supercontinuum generation. Conventional bright optical solitons result from the interaction of anomalous group-velocity dispersion and self-phase modulation. Here we experimentally demonstrate a class of bright soliton arising purely from the interaction of negative fourth-order dispersion and self-phase modulation, which can occur even for normal group-velocity dispersion. We provide experimental and numerical evidence of shape-preserving propagation and flat temporal phase for the fundamental pure-quartic soliton and periodically modulated propagation for the higher-order pure-quartic solitons. We derive the approximate shape of the fundamental pure-quartic soliton and discover that is surprisingly Gaussian, exhibiting excellent agreement with our experimental observations. Our discovery, enabled by precise dispersion engineering, could find applications in communications, frequency combs and ultrafast lasers.

  7. Geomorphology: Pure and applied

    SciTech Connect

    Hart, M.G.

    1986-01-01

    The book summarizes the history of intellectual debate in geomorphology and describes modern developments both ''pure'' and ''applied.'' The history begins well before W.M. Davis and follows through to such debates as those concerned with the Pleistocene. Modern developments in pure geomorphology are cast in terms of chapters on form, process, materials, and methods analysis. The applied chapters concentrate on environmental hazards and resources, and their management.

  8. From ketones to esters by a Cu-catalyzed highly selective C(CO)-C(alkyl) bond cleavage: aerobic oxidation and oxygenation with air.

    PubMed

    Huang, Xiaoqiang; Li, Xinyao; Zou, Miancheng; Song, Song; Tang, Conghui; Yuan, Yizhi; Jiao, Ning

    2014-10-22

    The Cu-catalyzed aerobic oxidative esterification of simple ketones via C-C bond cleavage has been developed. Varieties of common ketones, even inactive aryl long-chain alkyl ketones, are selectively converted into esters. The reaction tolerates a wide range of alcohols, including primary and secondary alcohols, chiral alcohols with retention of the configuration, electron-deficient phenols, as well as various natural alcohols. The usage of inexpensive copper catalyst, broad substrate scope, and neutral and open air conditions make this protocol very practical. (18)O labeling experiments reveal that oxygenation occurs during this transformation. Preliminary mechanism studies indicate that two novel pathways are mainly involved in this process. PMID:25251943

  9. Hyperbaric oxygen therapy in chronic vascular wound management.

    PubMed

    Wattel, F; Mathieu, D; Coget, J M; Billard, V

    1990-01-01

    Many nonhealing tissues are hypoxic, with oxygen tensions frequently ranging from 5 to 15 mmHg. In such an environment, the normal wound healing sequence is disrupted or halted and phagocytic killing activity depressed. So the adjunctive use of hyperbaric oxygen (HBO), based on physiologic data and clinical observations, can provide the substrate necessary to initiate and sustain the healing process. During a twelve-month period, 20 patients with a nonhealing wound were referred to the hyperbaric center: chronic arterial insufficiency ulcers in 9 cases, diabetic wounds (foot lesions) in 11 cases. Adjunctive HBO therapy, initiated twice a day, consisted of pure oxygen, 2.5 ATA, 90 min. The average length of sessions was 46 (15-108). Complete healing was observed in 15 of 20 cases. The wound management can be helped with the transcutaneous oxygen measurements under hyperbaric oxygen. The distal TCPO2 at 2.5 ATA pure oxygen is a reliable test to predict final outcome (healing or no change), when these values were not different in normal air and in normobaric oxygen: (table; see text) In hyperbaric oxygen therapy, when the distal TCPO2 value was inferior to 100 mmHg, all patients showed either no improvement or aggravation, and when the value was higher than 100 mmHg, wound healing was achieved with all patients. PMID:2306000

  10. Experimental evaluation of oxygen-enriched air and emulsified fuels in a single-cylinder diesel engine. Volume 1, Concept evaluation

    SciTech Connect

    Sekar, R.R.; Marr, W.W.; Cole, R.L.; Marciniak, T.J.

    1991-11-01

    The performance of a single-cylinder, direct-injection diesel engine was measured with intake oxygen levels of up to 35% and fuel water contents of up to 20%. Because a previous study indicated that the use of a less-expensive fuel would be more economical, two series of tests with No. 4 diesel fuel and No. 2 diesel fuel were conducted. To control the emissions of nitrogen oxides (NO{sub x}), water was introduced into the combustion process in the form of water-emulsified fuel, or the fuel injection timing was retarded. In the first series of tests, compressed oxygen was used; in the second series of tests, a hollow-tube membrane was used. Steady-state engine performance and emissions data were obtained. Test results indicated a large increase in engine power density, a slight improvement in thermal efficiency, and significant reductions in smoke and particulate-matter emissions. Although NO{sub x} emissions increased, they could be controlled by introducing water and retarding the injection timing. The results further indicated that thermal efficiency is slightly increased when moderately water-emulsified fuels are used, because a greater portion of the fuel energy is released earlier in the combustion process. Oxygen-enriched air reduced the ignition delay and caused the heat-release rate and cumulative heat-release rates to change measurably. Even at higher oxygen levels, NO{sub x} emissions decreased rapidly when the timing was retarded, and the amount of smoke and the level of particulate-matter emissions did not significantly increase. The single-cylinder engine tests confirmed the results of an earlier technical assessment and further indicated a need for a low-pressure-drop membrane specifically designed for oxygen enrichment. Extension data set indexed separately. 14 refs.

  11. Development of a 12-Thrust Chamber Kerosene /Oxygen Primary Rocket Sub-System for an Early (1964) Air-Augmented Rocket Ground-Test System

    NASA Technical Reports Server (NTRS)

    Pryor, D.; Hyde, E. H.; Escher, W. J. D.

    1999-01-01

    Airbreathing/Rocket combined-cycle, and specifically rocket-based combined- cycle (RBCC), propulsion systems, typically employ an internal engine flow-path installed primary rocket subsystem. To achieve acceptably short mixing lengths in effecting the "air augmentation" process, a large rocket-exhaust/air interfacial mixing surface is needed. This leads, in some engine design concepts, to a "cluster" of small rocket units, suitably arrayed in the flowpath. To support an early (1964) subscale ground-test of a specific RBCC concept, such a 12-rocket cluster was developed by NASA's Marshall Space Flight Center (MSFC). The small primary rockets used in the cluster assembly were modified versions of an existing small kerosene/oxygen water-cooled rocket engine unit routinely tested at MSFC. Following individual thrust-chamber tests and overall subsystem qualification testing, the cluster assembly was installed at the U. S. Air Force's Arnold Engineering Development Center (AEDC) for RBCC systems testing. (The results of the special air-augmented rocket testing are not covered here.) While this project was eventually successfully completed, a number of hardware integration problems were met, leading to catastrophic thrust chamber failures. The principal "lessons learned" in conducting this early primary rocket subsystem experimental effort are documented here as a basic knowledge-base contribution for the benefit of today's RBCC research and development community.

  12. Oxygen therapy and intraocular oxygenation.

    PubMed Central

    Jampol, L M

    1987-01-01

    When delivered to the corneal surface of rabbits or monkeys, 100% oxygen can significantly increase the pO2 in the aqueous humor. Under hyperbaric conditions (two atmospheres), an observed rise in the aqueous pO2 in rabbits breathing room air can be increased further by exposing the rabbit cornea to 100% oxygen. The high oxygen levels under hyperbaric conditions are mediated by intravascular and transcorneal delivery of oxygen. The increase in the pO2 levels in the aqueous can prevent sickling of intracameral human erythrocytes containing sickle hemoglobin. Thus, oxygen therapy transcorneally or systemically could potentially be used to treat a sickle cell hyphema. The exposure of rabbit eyes to 100% oxygen at the corneal surface is followed by autoregulation (constriction) of the iris vasculature. We could demonstrate no constriction in the eyes of two normal human volunteers or of four patients with chronic stable rubeosis iridis. Preretinal vitreous pO2 levels can be significantly raised by exposing monkeys to hyperbaric 100% oxygen. This procedure may be of value in treating acute, reversible ischemic inner retinal diseases. Transcorneal or vascular delivery of oxygen to the eye under normobaric or hyperbaric conditions may be effective in treating ischemic diseases of the anterior segment, such as anterior segment necrosis or rubeosis iridis, or ischemic inner retinal diseases. Images FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 B FIGURE 5 C FIGURE 5 A FIGURE 6 PMID:3447339

  13. Pure uterine lipoma.

    PubMed

    Erdem, Gulnur; Celik, Onder; Karakas, Hakki Muammer; Alkan, Alpay; Hascalik, Seyma

    2007-10-01

    Lipomatous tumors of the uterus are unusual, benign neoplasms seen in postmenopausal women. Although many of the mixed-type cases such as lipoleiomyoma and fibrolipoma have been reported, pure uterine lipomas are extremely rare. In the literature, a few cases with pure uterine lipoma have been reported. We first present the advanced magnetic resonance findings of pure uterine lipoma, followed by those of ultrasonography (US) and computed tomography (CT). We markedly detected lipid peaks on the magnetic resonance spectroscopy (MRS) and the apparent diffusion coefficient value to be 0.00 due to chemical-shift effects with diffusion-weighted imaging (DWI). Although pelvic lipomatous tumors can be diagnosed with US and CT, in some cases, further workup may be required to localize the lesion. MRI may yield more valuable data for differential diagnosis. MRS and DWI findings provide additional clues on the nature of the lesion. PMID:17905250

  14. Fires and Burns Involving Home Medical Oxygen

    MedlinePlus

    ... nfpa.org Fires and Burns Involving Home Medical Oxygen The air is normally 21% oxygen. Oxygen is not flammable, but fire needs it to burn. ¾ When more oxygen is present, any fire that starts will burn ...

  15. Final report on the project entitled: Highly Preheated Combustion Air System with/without Oxygen Enrichment for Metal Processing Furnaces

    SciTech Connect

    Arvind Atreya

    2007-02-16

    This work develops and demonstrates a laboratory-scale high temperature natural gas furnace that can operate with/without oxygen enrichment to significantly improve energy efficiency and reduce emissions. The laboratory-scale is 5ft in diameter & 8ft tall. This furnace was constructed and tested. This report demonstrates the efficiency and pollutant prevention capabilities of this test furnace. The project also developed optical detection technology to control the furnace output.

  16. Rapid increases in the steady-state concentration of reactive oxygen species in the lungs and heart after particulate air pollution inhalation.

    PubMed Central

    Gurgueira, Sonia A; Lawrence, Joy; Coull, Brent; Murthy, G G Krishna; González-Flecha, Beatriz

    2002-01-01

    In vitro studies suggest that reactive oxygen species contribute to the cardiopulmonary toxicity of particulate air pollution. To evaluate the ability of particulate air pollution to promote oxidative stress and tissue damage in vivo, we studied a rat model of short-term exposure to concentrated ambient particles (CAPs). We exposed adult Sprague-Dawley rats to either CAPs aerosols (group 1; average CAPs mass concentration, 300 +/- 60 micro g/m3) or filtered air (sham controls) for periods of 1-5 hr. Rats breathing CAPs aerosols for 5 hr showed significant oxidative stress, determined as in situ chemiluminescence in the lung [group 1, 41 +/- 4; sham, 24 +/- 1 counts per second (cps)/cm2] and heart (group 1, 45 +/- 4; sham, 24 +/- 2 cps/cm2) but not liver (group 1, 10 +/- 3; sham, 13 +/- 3 cps/cm2). Increases in oxidant levels were also triggered by highly toxic residual oil fly ash particles (lung chemiluminescence, 90 +/- 10 cps/cm2; heart chemiluminescence, 50 +/- 3 cps/cm2) but not by particle-free air or by inert carbon black aerosols (control particles). Increases in chemiluminescence showed strong associations with the CAPs content of iron, manganese, copper, and zinc in the lung and with Fe, aluminum, silicon, and titanium in the heart. The oxidant stress imposed by 5-hr exposure to CAPs was associated with slight but significant increases in the lung and heart water content (approximately 5% in both tissues, p < 0.05) and with increased serum levels of lactate dehydrogenase (approximately 80%), indicating mild damage to both tissues. Strikingly, CAPs inhalation also led to tissue-specific increases in the activities of the antioxidant enzymes superoxide dismutase and catalase, suggesting that episodes of increased particulate air pollution not only have potential for oxidant injurious effects but may also trigger adaptive responses. PMID:12153754

  17. The doping effect on the catalytic activity of graphene for oxygen evolution reaction in a lithium-air battery: a first-principles study.

    PubMed

    Ren, Xiaodong; Wang, Beizhou; Zhu, Jinzhen; Liu, Jianjun; Zhang, Wenqing; Wen, Zhaoyin

    2015-06-14

    A lithium-air battery as an energy storage technology can be used in electric vehicles due to its large energy density. However, its poor rate capability, low power density and large overpotential problems limit its practical usage. In this paper, the first-principles thermodynamic calculations were performed to study the catalytic activity of X-doped graphene (X = B, N, Al, Si, and P) materials as potential cathodes to enhance charge reactions in a lithium-air battery. Among these materials, P-doped graphene exhibits the highest catalytic activity in reducing the charge voltage by 0.25 V, while B-doped graphene has the highest catalytic activity in decreasing the oxygen evolution barrier by 0.12 eV. By combining these two catalytic effects, B,P-codoped graphene was demonstrated to have an enhanced catalytic activity in reducing the O2 evolution barrier by 0.70 eV and the charge voltage by 0.13 V. B-doped graphene interacts with Li2O2 by Li-sited adsorption in which the electron-withdrawing center can enhance charge transfer from Li2O2 to the substrate, facilitating reduction of O2 evolution barrier. In contrast, X-doped graphene (X = N, Al, Si, and P) prefers O-sited adsorption toward Li2O2, forming a X-O2(2-)···Li(+) interface structure between X-O2(2-) and the rich Li(+) layer. The active structure of X-O2(2-) can weaken the surrounding Li-O2 bonds and significantly reduce Li(+) desorption energy at the interface. Our investigation is helpful in developing a novel catalyst to enhance oxygen evolution reaction (OER) in Li-air batteries. PMID:25970821

  18. Production of pure metals

    NASA Technical Reports Server (NTRS)

    Philipp, W. H.; Marsik, S. J.; May, C. E. (Inventor)

    1974-01-01

    A process for depositing elements by irradiating liquids is reported. Ultra pure elements are precipitated from aqueous solutions or suspensions of compounds. A solution of a salt of a metal to be prepared is irradiated, and the insoluble reaction product settles out. Some chemical compounds may also be prepared in this manner.

  19. Dahlbeck and Pure Ontology

    ERIC Educational Resources Information Center

    Mackenzie, Jim

    2016-01-01

    This article responds to Johan Dahlbeck's "Towards a pure ontology: Children's bodies and morality" ["Educational Philosophy and Theory," vol. 46 (1), 2014, pp. 8-23 (EJ1026561)]. His arguments from Nietzsche and Spinoza do not carry the weight he supposes, and the conclusions he draws from them about pedagogy would be…

  20. Evaluation of reactive oxygen species generating AirOcare system for reducing airborne microbial populations in a meat processing plant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The microbial contamination of meat and meat products is of continuing concern to the meat industry and regulatory agencies. Air has been established as a source of microbial contamination in slaughter and processing facilities. The objective of this research was to determine the efficacy of reactiv...

  1. Improvement of oxygen transfer coefficient during Penicillium canescens culture. Influence of turbine design, agitation speed, and air flow rate on xylanase production.

    PubMed

    Gaspar, A; Strodiot, L; Thonart, P

    1998-01-01

    To improve xylanase productivity from Penicillium canescens 10-10c culture, an optimization of oxygen supply is required. Because the strain is sensitive to shear forces, leading to lower xylanase productivity as to morphological alteration, vigorous mixing is not desired. The influence of turbine design, agitation speed, and air flow rate on K1a (global mass transfer coefficient, h(-1)) and enzyme production is discussed. K1a values increased with agitation speed and air flow rate, whatever the impeller, in our assay conditions. Agitation had more influence on K1a values than air flow, when a disk-mounted blade's impeller (DT) is used; an opposite result was obtained with a hub-mounted pitched blade's impeller (PBT). Xylanase production appeared as a function of specific power (W/m3), and an optimum was found in 20 and 100 L STRs fitted with DT impellers. On the other hand, the use of a hub-mounted pitched blade impeller (PBT8), instead of a disk-mounted blade impeller (DT4), reduced the lag time of hemicellulase production and increased xylanase productivity 1.3-fold. PMID:18576019

  2. Behavior of oxide scales on 2. 25Cr-1Mo steel during thermal cycling. I. Scales formed in oxygen and air

    SciTech Connect

    Christl, W.; Rahmel, A.; Schuetze, M.

    1989-02-01

    The acoustic-emission (AE) technique has been applied to study scale-damage processes during thermal cycling of a tube, preferentially between 600 and 300/degree/C in air, oxygen, and air + 0.5% SO/sub 2/. The AE measurements were accompanied by optical and electron-optical investigations on tube rings exposed to the same cycling conditions. During the first period of cycling, a scale rich in hematite is formed. It suffers compressive stresses during cooling. The result is a buckled multilayered scale with separated lamellae. The scaling rate is lower than under isothermal conditions. AE signals start after 175/degree/C cooling. After longer exposure times, the scale contains an increasing amount of magnetite and becomes more compact. The scaling rate increases and is comparable to that under isothermal conditions. AE signals are already observed after 50/degree/C cooling and are correlated with crack formation in the magnetite caused by tensile stresses there. The addition of SO/sub 2/ to air enhances the crack-healing process due to higher Fe diffusion in FeS. The scale is more compact.

  3. Cobaltite oxide nanosheets anchored graphene nanocomposite as an efficient oxygen reduction reaction (ORR) catalyst for the application of lithium-air batteries

    NASA Astrophysics Data System (ADS)

    Gnana kumar, G.; Christy, Maria; Jang, Hosaeng; Nahm, Kee Suk

    2015-08-01

    The graphene/cubic cobaltite oxide nanosheets (rGO/Co3O4) with a face centered cubic crystalline structure are synthesized and are exploited as effective cathode catalysts in high performance Lithium-air batteries. The morphological images enunciate that 220 nm average diameter of Co3O4 nanosheets are effectively anchored over the graphene sheets and the diameter of individual nanoparticles that construct the cubic nanosheets is 5 nm. The growth and composite formation mechanisms of prepared nanostructures are identified from Raman and FT-IR spectroscopic techniques. rGO/Co3O4 composite exhibits a lower voltage, high discharge capacity of 4150 mAh g-1 and displays superior cyclability without any capacity losses, signifying the excellent rechargeability of the fabricated electrodes. The post mortem analysis of electrodes specify the existence of lithium peroxide (Li2O2), lithium oxide (Li2O) and lithium carbonate (Li2CO3) discharge products, revealing the involved electrochemical reaction of Lithium-air batteries. The excellent electrochemical properties of rGO/Co3O4 composite is due to the combination of rapid electrokinetics of electron transport and high electrocatalytic activity toward oxygen reduction reaction given via the synergetic effects of rGO and cubic Co3O4 nanosheets. These findings provide fundamental knowledge on understanding the influence of morphological and structural properties of graphene based nanostructures toward Lithium-air battery performances.

  4. Medical Oxygen Safety

    MedlinePlus

    ... to the air a patient uses to breathe. Fire needs oxygen to burn. If a fire should start in an oxygen-enriched area, the ... Homes where medical oxygen is used need specific fire safety rules to keep people safe from fire ...

  5. A lithium-air fuel cell using copper to catalyze oxygen-reduction based on copper-corrosion mechanism.

    PubMed

    Wang, Yonggang; Zhou, Haoshen

    2010-09-14

    The copper-catalyzed O(2) reduction in aqueous electrolyte and the Li-anode in organic electrolyte were united together by a ceramic Li-ions exchange film to form a lithium-air fuel cell. The achieved results demonstrate the cycle between Cu and Cu(2)O can be used to catalyze O(2) electrochemical reduction based on the copper-corrosion mechanism. PMID:20668776

  6. A metal-free, lithium-ion oxygen battery: a step forward to safety in lithium-air batteries.

    PubMed

    Hassoun, Jusef; Jung, Hun-Gi; Lee, Dong-Ju; Park, Jin-Bum; Amine, Khalil; Sun, Yang-Kook; Scrosati, Bruno

    2012-11-14

    A preliminary study of the behavior of lithium-ion-air battery where the common, unsafe lithium metal anode is replaced by a lithiated silicon-carbon composite, is reported. The results, based on X-ray diffraction and galvanostatic charge-discharge analyses, demonstrate the basic reversibility of the electrochemical process of the battery that can be promisingly cycled with a rather high specific capacity. PMID:23077970

  7. Pure Lovelock Kasner metrics

    NASA Astrophysics Data System (ADS)

    Camanho, Xián O.; Dadhich, Naresh; Molina, Alfred

    2015-09-01

    We study pure Lovelock vacuum and perfect fluid equations for Kasner-type metrics. These equations correspond to a single Nth order Lovelock term in the action in d=2N+1,2N+2 dimensions, and they capture the relevant gravitational dynamics when aproaching the big-bang singularity within the Lovelock family of theories. Pure Lovelock gravity also bears out the general feature that vacuum in the critical odd dimension, d=2N+1, is kinematic, i.e. we may define an analogue Lovelock-Riemann tensor that vanishes in vacuum for d=2N+1, yet the Riemann curvature is non-zero. We completely classify isotropic and vacuum Kasner metrics for this class of theories in several isotropy types. The different families can be characterized by means of certain higher order 4th rank tensors. We also analyze in detail the space of vacuum solutions for five- and six dimensional pure Gauss-Bonnet theory. It possesses an interesting and illuminating geometric structure and symmetries that carry over to the general case. We also comment on a closely related family of exponential solutions and on the possibility of solutions with complex Kasner exponents. We show that the latter imply the existence of closed timelike curves in the geometry.

  8. Determination of Phosphorescence Quantum Yield of Singlet Oxygen O 2( 1Δ g) Photosensitized by Phenalenone in Air-Saturated Carbon Tetrachloride

    NASA Astrophysics Data System (ADS)

    Shimizu, Okiyasu; Watanabe, Jun; Imakubo, Keiichi; Naito, Shizuo

    1998-11-01

    The phosphorescence quantum yield Φ P (=einsteins emitted/einsteins absorbed by sensitizer) of singlet oxygen (1O2) was measured for an air-saturated CCl4 solution of phenalenone (PH) used as a photosensitizer, by means of a photon-counting technique based on the use of a near-IR-sensitive photomultiplier. Employment of steady-state excitation allowed for the determination of the absolute quantum yield of Φ P=(1.38±0.05)×10-3 in CCl4. The result was obtained by direct comparison of the areas under the corrected emission spectra of 1O2 and of quinine bisulfate (QBS) in 1N H2SO4 as a luminescence standard.

  9. Porous nitrogen-doped carbon nanosheet on graphene as metal-free catalyst for oxygen reduction reaction in air-cathode microbial fuel cells.

    PubMed

    Wen, Qing; Wang, Shaoyun; Yan, Jun; Cong, Lijie; Chen, Ye; Xi, Hongyuan

    2014-02-01

    Porous nitrogen-doped carbon nanosheet on graphene (PNCN) was used as an alternative cathode catalyst for oxygen reduction reaction (ORR) in air-cathode microbial fuel cells (MFCs). Here we report a novel, low-cost, scalable, synthetic method for preparation of PNCN via the carbonization of graphite oxide-polyaniline hybrid (GO-PANI), subsequently followed by KOH activation treatment. Due to its high concentration of nitrogen and high specific surface area, PNCN exhibited an excellent catalytic activity for ORR. As a result, the maximum power density of 1159.34mWm(-2) obtained with PNCN catalyst was higher than that of Pt/C catalyst (858.49mWm(-2)) in a MFC. Therefore, porous nitrogen-doped carbon nanosheet could be a good alternative to Pt catalyst in MFCs. PMID:24239870

  10. Effects of negative air ions on oxygen uptake kinetics, recovery and performance in exercise: a randomized, double-blinded study

    NASA Astrophysics Data System (ADS)

    Nimmerichter, Alfred; Holdhaus, Johann; Mehnen, Lars; Vidotto, Claudia; Loidl, Markus; Barker, Alan R.

    2014-09-01

    Limited research has suggested that acute exposure to negatively charged ions may enhance cardio-respiratory function, aerobic metabolism and recovery following exercise. To test the physiological effects of negatively charged air ions, 14 trained males (age: 32 ± 7 years; : 57 ± 7 mL min-1 kg-1) were exposed for 20 min to either a high-concentration of air ions (ION: 220 ± 30 × 103 ions cm-3) or normal room conditions (PLA: 0.1 ± 0.06 × 103 ions cm-3) in an ionization chamber in a double-blinded, randomized order, prior to performing: (1) a bout of severe-intensity cycling exercise for determining the time constant of the phase II response ( τ) and the magnitude of the slow component (SC); and (2) a 30-s Wingate test that was preceded by three 30-s Wingate tests to measure plasma [adrenaline] (ADR), [nor-adrenaline] (N-ADR) and blood [lactate] (BLac) over 20 min during recovery in the ionization chamber. There was no difference between ION and PLA for the phase II τ (32 ± 14 s vs. 32 ± 14 s; P = 0.7) or SC (404 ± 214 mL vs 482 ± 217 mL; P = 0.17). No differences between ION and PLA were observed at any time-point for ADR, N-ADR and BLac as well as on peak and mean power output during the Wingate tests (all P > 0.05). A high-concentration of negatively charged air ions had no effect on aerobic metabolism during severe-intensity exercise or on performance or the recovery of the adrenergic and metabolic responses after repeated-sprint exercise in trained athletes.

  11. Associations of autophagy with lung diffusion capacity and oxygen saturation in severe COPD: effects of particulate air pollution

    PubMed Central

    Lee, Kang-Yun; Chiang, Ling-Ling; Ho, Shu-Chuan; Liu, Wen-Te; Chen, Tzu-Tao; Feng, Po-Hao; Su, Chien-Ling; Chuang, Kai-Jen; Chang, Chih-Cheng; Chuang, Hsiao-Chi

    2016-01-01

    Although traffic exposure has been associated with the development of COPD, the role of particulate matter <10 μm in aerodynamic diameter (PM10) in the pathogenesis of COPD is not yet fully understood. We assessed the 1-year effect of exposure to PM10 on the pathogenesis of COPD in a retrospective cohort study. We recruited 53 subjects with COPD stages III and IV and 15 healthy controls in a hospital in Taiwan. We estimated the 1-year annual mean levels of PM10 at all residential addresses of the cohort participants. Changes in PM10 for the 1-year averages in quintiles were related to diffusion capacity of the lung for carbon monoxide levels (r=−0.914, P=0.029), changes in the pulse oxygen saturation (ΔSaO2; r=−0.973, P=0.005), receptor for advanced glycation end-products (r=−0.881, P=0.048), interleukin-6 (r=0.986, P=0.002), ubiquitin (r=0.940, P=0.017), and beclin 1 (r=0.923, P=0.025) in COPD. Next, we observed that ubiquitin was correlated with ΔSaO2 (r=−0.374, P=0.019). Beclin 1 was associated with diffusion capacity of the lung for carbon monoxide (r=−0.362, P=0.028), ΔSaO2 (r=−0.354, P=0.032), and receptor for advanced glycation end-products (r=−0.471, P=0.004). Autophagy may be an important regulator of the PM10-related pathogenesis of COPD, which could cause deterioration in the lung diffusion capacity and oxygen saturation. PMID:27468231

  12. Oxygen transport resistance at gas diffusion layer - Air channel interface with film flow of water in a proton exchange membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Koz, Mustafa; Kandlikar, Satish G.

    2016-01-01

    Water present as films on the gas diffusion layer-air channel interface in a proton exchange membrane fuel cell (PEMFC) alters the oxygen transport resistance, which is expressed through Sherwood number (Sh). The effect of multiple films along the flow length on Sh is investigated through 3D and stationary simulations. The effects of air Péclet number, non-dimensional film width, length, and spacing are studied. Using the simulation results, non-dimensional correlations are developed for local Sh within a mean absolute percentage error of 9%. These correlations can be used for simulating PEMFC performance over temperature and relative humidity ranges of 20-80 °C and 0-100%, respectively. Sh on the film side can be up to 31% lower than that for a dry channel, while a film may reduce the interfacial width by up to 39%. The corresponding increase in transport resistance results in lowering the voltage by 5 and 8 mV respectively at a current density of 1.5 A cm-2. However, their combined effect leads to a voltage loss of 20 mV due to this additional mass transport resistance. It is therefore important to incorporate the additional resistance introduced by the films while modeling fuel cell performance.

  13. Highly ordered and ultra-long carbon nanotube arrays as air cathodes for high-energy-efficiency Li-oxygen batteries

    NASA Astrophysics Data System (ADS)

    Yu, Ruimin; Fan, Wugang; Guo, Xiangxin; Dong, Shaoming

    2016-02-01

    Carbonaceous air cathodes with rational architecture are vital for the nonaqueous Li-O2 batteries to achieve large energy density, high energy efficiency and long cycle life. In this work, we report the cathodes made of highly ordered and vertically aligned carbon nanotubes grown on permeable Ta foil substrates (VACNTs-Ta) via thermal chemical vapour deposition. The VACNTs-Ta, composed of uniform carbon nanotubes with approximately 240 μm in superficial height, has the super large surface area. Meanwhile, the oriented carbon nanotubes provide extremely outstanding passageways for Li ions and oxygen species. Electrochemistry tests of VACNTs-Ta air cathodes show enhancement in discharge capacity and cycle life compared to those made from short-range oriented and disordered carbon nanotubes. By further combining with the LiI redox mediator that is dissolved in the tetraethylene dimethyl glycol based electrolytes, the batteries exhibit more than 200 cycles at the current density of 200 mA g-1 with a cut-off discharge capacity of 1000 mAh g-1, and their energy efficiencies increase from 50% to 82%. The results here demonstrate the importance of cathode construction for high-energy-efficiency and long-life Li-O2 batteries.

  14. Demonstration of cost-effective NO{sub x} reduction on a regenerative sideport glass furnace using oxygen-enriched air staging

    SciTech Connect

    Mohr, P.; Neff, D.; Rue, D.

    1996-12-31

    The Gas Research Institute (GRI), the U.S. Department of Energy (DOE), and the Southern California Gas Company (SoCal) have joined with the development team of the Institute of Gas Technology (IGT), Combustion Tec, Inc. (CTI), and Air Products and Chemicals, Inc. (APCI) and provided support for extension of the oxygen-enriched air staging (OEAS) NO{sub x} control technology to natural gas-fired sideport regenerative glass melters. In previous demonstrations, the OEAS technology has successfully reduced NO{sub x} emissions by more than 50% on natural gas-fired endport regenerative glass melters without any adverse impacts on furnace performance or glass quality. In the current program, Owens-Brockway (OB) provided operations expertise and a 6 port pair, sideport furnace for field evaluation tests of OEAS. Background and initial test results for a single port pair and the complete furnace are presented along with CFD modeling results for OEAS on a single port pair of the sideport furnace. Modeling results confirm the capacity of OEAS to provide significant NO{sub x} reduction and CO burnout while maintaining or increasing thermal efficiency and furnace production rate.

  15. A comparison of measured and predicted test flow in an expansion tube with air and oxygen test gases

    NASA Technical Reports Server (NTRS)

    Aaggard, K. V.; Goad, W. K.

    1975-01-01

    Simultaneous time-resolved measurements of temperature, density, pitot pressure, and wall pressure in both air and O2 test gases were obtained in the Langley pilot model expansion tube. These tests show nonequilibrium chemical and vibrational relaxation significantly affect the test-flow condition. The use of an electromagnetic device to preopen the secondary diaphragm before the arrival of the primary shock wave resulted in an improvement in the agreement between the measured pitot pressure and the value inferred from measured density and interface velocity. Boundary-layer splitter plates used to reduce the wall boundary layer show that this disagreement in the measured and inferred pitot pressures is not a result of boundary-layer effects.

  16. A case study of air enrichment in rotary kiln incineration

    SciTech Connect

    Melo, G.F.; Lacava, P.T.; Carvalho, J.A. Jr.

    1998-07-01

    This paper presents a case study of air enrichment in an industrial rotary kiln type incineration unit. The study is based on mass and energy balances, considering the combustion reaction of a mixture composed by the residue and the auxiliary fuel with air enriched with oxygen. The steps are shown for the primary chamber (rotary kiln) and secondary chamber (afterburner). The residence times in the primary and secondary chamber are 2.0 and 3.2 sec, respectively. The pressure is atmospheric in both chambers. Based on constant chamber gas residence time and gas temperature, it is shown that the residue input rates can be increased by one order of magnitude as air is substituted by pure oxygen. As the residue consumption rate in the rotary kiln is also dependent on residue physical characteristics (mainly size), the study was also carried out for different percentages of oxygen in the oxidizer gas.

  17. 7 CFR 917.8 - Pure grower or pure producer.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN CALIFORNIA Order Regulating Handling Definitions § 917.8 Pure grower or pure producer. (a) For peaches,...

  18. 7 CFR 917.8 - Pure grower or pure producer.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN CALIFORNIA Order Regulating Handling Definitions § 917.8 Pure grower or pure producer. (a) For peaches,...

  19. Monolithic solid electrolyte oxygen pump

    DOEpatents

    Fee, Darrell C.; Poeppel, Roger B.; Easler, Timothy E.; Dees, Dennis W.

    1989-01-01

    A multi-layer oxygen pump having a one-piece, monolithic ceramic structure affords high oxygen production per unit weight and volume and is thus particularly adapted for use as a portable oxygen supply. The oxygen pump is comprised of a large number of small cells on the order of 1-2 millimeters in diameter which form the walls of the pump and which are comprised of thin, i.e., 25-50 micrometers, ceramic layers of cell components. The cell components include an air electrode, an oxygen electrode, an electrolyte and interconnection materials. The cell walls form the passages for input air and for exhausting the oxygen which is transferred from a relatively dilute gaseous mixture to a higher concentration by applying a DC voltage across the electrodes so as to ionize the oxygen at the air electrode, whereupon the ionized oxygen travels through the electrolyte and is converted to oxygen gas at the oxygen electrode.

  20. A method for estimating the volume of oxygen required by Channel Catfish Ictalurus Punctatus and Blue Catfish Ictalurus Furcatus, during transport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most transporters of live fish provide supplemental aeration by diffusing pure oxygen in hauling tanks. Transporters typically use a thumb rule approach, in which knowledge of a particular species, ambient air temperature, haul tank water temperature, loading density, and transport time are consider...

  1. Pure Autonomic Failure.

    PubMed

    Thaisetthawatkul, Pariwat

    2016-08-01

    Pure autonomic failure (PAF) is a rare sporadic neurodegenerative autonomic disorder characterized by slowly progressive pan autonomic failure without other features of neurologic dysfunctions. The main clinical symptoms result from neurogenic orthostatic hypotension and urinary and gastrointestinal autonomic dysfunctions. Autonomic failure in PAF is caused by neuronal degeneration of pre- and postganglionic sympathetic and parasympathetic neurons in the thoracic spinal cord and paravertebral autonomic ganglia. The presence of Lewy bodies and α-synuclein deposits in these neural structures suggests that PAF is one of Lewy body synucleinopathies, examples of which include multiple system atrophy, Parkinson disease, and Lewy body disease. There is currently no specific treatment to stop progression in PAF. Management of autonomic symptoms is the mainstay of treatment and includes management of orthostatic hypotension and supine hypertension. The prognosis for survival of PAF is better than for the other synucleinopathies. PMID:27338613

  2. Novel Membranes and Processes for Oxygen Enrichment

    SciTech Connect

    Lin, Haiqing

    2011-11-15

    The overall goal of this project is to develop a membrane process that produces air containing 25-35% oxygen, at a cost of $25-40/ton of equivalent pure oxygen (EPO2). Oxygen-enriched air at such a low cost will allow existing air-fueled furnaces to be converted economically to oxygen-enriched furnaces, which in turn will improve the economic and energy efficiency of combustion processes significantly, and reduce the cost of CO{sub 2} capture and sequestration from flue gases throughout the U.S. manufacturing industries. During the 12-month Concept Definition project: We identified a series of perfluoropolymers (PFPs) with promising oxygen/nitrogen separation properties, which were successfully made into thin film composite membranes. The membranes showed oxygen permeance as high as 1,200 gpu and oxygen/nitrogen selectivity of 3.0, and the permeance and selectivity were stable over the time period tested (60 days). We successfully scaled up the production of high-flux PFP-based membranes, using MTR's commercial coaters. Two bench-scale spiral-wound modules with countercurrent designs were made and parametric tests were performed to understand the effect of feed flow rate and pressure, permeate pressure and sweep flow rate on the membrane module separation properties. At various operating conditions that modeled potential industrial operating conditions, the module separation properties were similar to the pure-gas separation properties in the membrane stamps. We also identified and synthesized new polymers [including polymers of intrinsic microporosity (PIMs) and polyimides] with higher oxygen/nitrogen selectivity (3.5-5.0) than the PFPs, and made these polymers into thin film composite membranes. However, these membranes were susceptible to severe aging; pure-gas permeance decreased nearly six-fold within two weeks, making them impractical for industrial applications of oxygen enrichment. We tested the effect of oxygen-enriched air on NO{sub x} emissions using a

  3. Pure autonomic failure.

    PubMed

    Garland, Emily M; Hooper, William B; Robertson, David

    2013-01-01

    A 1925 report by Bradbury and Eggleston first described patients with extreme orthostatic hypotension and a low, steady heart rate. Evidence accumulated over the next two decades that patients with orthostatic hypotension include those with pure autonomic failure (PAF), characterized by isolated peripheral autonomic dysfunction and decreased norepinephrine synthesis; multiple system atrophy (MSA) with symptoms of a central Parkinson-like syndrome and normal resting plasma norepinephrine; and Parkinson's disease (PD), with lesions in postganglionic noradrenergic neurons and signs of autonomic dysfunction. All three disorders are classified as α-synucleinopathies. Insoluble deposits of α-synuclein are found in glia in MSA, whereas they take the form of neuronal cytoplasmic inclusions called Lewy bodies in PAF and PD. The exact relationship between α-synuclein deposits and the pathology remains undetermined. PAF occurs sporadically, and progresses slowly with a relatively good prognosis. However, it has been proposed that some cases of PAF may develop a central neurodegenerative disorder. Differentiation between PAF, MSA, and PD with autonomic failure can be facilitated by a number of biochemical and functional tests and by imaging studies. Cardiac sympathetic innervation is generally intact in MSA but decreased or absent in Parkinson's disease with autonomic failure and PAF. Treatment of PAF is directed at relieving symptoms with nonpharmacological interventions and with medications producing volume expansion and vasoconstriction. Future studies should focus on determining the factors that lead to central rather than solely peripheral neurodegeneration. PMID:24095130

  4. Field evaluation and calibration of a small axial passive air sampler for gaseous and particle bound polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAHs.

    PubMed

    Magnusson, Roger; Arnoldsson, Kristina; Lejon, Christian; Hägglund, Lars; Wingfors, Håkan

    2016-09-01

    Polycyclic aromatic hydrocarbons (PAHs) and their oxygenated analogues (OPAHs) are ubiquitous air pollutants known to cause adverse health effects. PAH air levels are commonly monitored by active sampling but passive sampling has become popular because of its lower cost and simplicity, which facilitate long-term sampling and increased spatial coverage. However, passive samplers are less suitable for short-term sampling and are in general less accurate than active samplers because they require reliable sampling rate (Rs) measurements for individual analytes under diverse environmental conditions. In this study a small passive sampler designed to sample both particle-bound and gaseous compounds was evaluated and calibrated for PAHs and OPAHs in a traffic environment by co-deployment with active samplers for two weeks. Despite the relatively low average air concentrations of PM10 (20 μg/m(3)), PM2.5 (5 μg/m(3)), total PAHs (4.2 ng/m(3)), and OPAHs (2.3 ng/m(3)) at the site, detectable quantities (on average 24 times above blank values) of the full range of PAHs and OPAHs were captured, with low variability (average RSD of 16%). This was accomplished by using a Tenax(®) TA-modified glass fiber substrate that is compatible with highly sensitive thermal desorption GC-MS analysis, which made it possible to achieve detection limits per sample in the pg range. Experiments with inverted samplers revealed that the relative contribution of gravitational settling to the sampling of particles carrying PAHs and OPAHs was around 3.5 times larger than other deposition mechanisms. Average Rs values for individual OPAHs and PAHs were 0.046 ± 0.03 m(3)/day and 0.12 ± 0.07 m(3)/day, respectively, with no appreciable difference between the values for particle-associated and gaseous compounds. Furthermore, the Rs values were competitive with other currently used passive samplers if normalized for substrate area. Overall, the new sampler's performance, simplicity and

  5. Desulfurization of pure coal macerals

    SciTech Connect

    Hippo, E.J. ); Crelling, J.C. )

    1988-06-01

    The objectives of this study were to modify the present density gradient centrifugation (DGC) techniques for coal macerals to obtain 10-20 grams of target maceral concentrates and to determine the reactivity or ease of removing the organic sulfur in the various macerals with supercritical methanol extraction. Although the chemistry needed for this objective is not difficult, the accumulation of 10 to 20 gram quantities of ''pure'' petrographically verified single maceral concentrates has not been possible until now. The results of recent work have demonstrated that the individual macerals can be separated and verified. The accumulation of much larger quantities than have previously been separated was a problem that has been overcome by pre-concentrating target macerals at their density cut points. Supercritical fluid extraction of coals has previously been reported as a method in the production of liquid fuel products from coal under mild conditions and as a medium for selective desulfurization of coal. Alcohols are expected to exhibit greater solubility for polar organic molecules due to hydrogen bonding and dipole attractive forces, also providing the opportunity for chemical reactions during the extraction due to the nucleophilicity of the alcohol oxygen and the tendency to act as a hydrogen donor. In addition, enol rearrangements may play a role in desulfurization. As previously reported different supercritical reaction conditions produced different extents of desulfurization of coals (33.9 - 65.7%). These variable desulfurizations are probably a result of differences in extents of conversion of the pyritic sulfur (to various alteration products, such as pyrrhotite), as well as organic sulfur functionalities (thiophenol, sulfide, and thiopenes) to light gases such as dimethylsulfide, hydrogen sulfide, and methylmercaptons.

  6. Desulfurization of pure coal macerals

    SciTech Connect

    Hippo, E.J.; Crelling, J.C. )

    1988-01-01

    The objectives of this study were to modify the present density gradient centrifugation (DGC) techniques for coal macerals to obtain 10-20 grams of target maceral concentrates and to determine the reactivity or ease of removing the organic sulfur in the various macerals with supercritical methanol extraction. Although the chemistry needed for this objective is not difficult, the accumulation of 10 to 20 gram quantities of pure petrographically verified single maceral concentrates has not been possible until now. The results of recent work have demonstrated that the individual macerals can be separated and verified. The accumulation of much larger quantities than have previously been separated was a problem that has been overcome by pre-concentrating target macerals at their density cut points. Supercritical fluid extraction of coals has previously been reported as a method in the production of liquid fuel products from coal under mild conditions and as a medium for selective desulfurization of coal. Alcohols are expected to exhibit greater solubility for polar organic molecules due to hydrogen bonding and dipole attractive forces, also providing the opportunity for chemical reactions during the extraction due to the nucleophilicity of the alcohol oxygen and the tendency to act as a hydrogen donor. In addition, enol rearrangements may play a role in desulfurization. As previously reported different supercritical reaction conditions produced different extents of desulfurization of coals (33.9 - 65.7%). These variable desulfurizations are probably a result of differences in extents of conversion of the pyritic sulfur (to various alteration products, such as pyrrhotite), as well as organic sulfur functionalities (thiophenol, sulfide, and thiophenes) to light gases such as dimethylsulfide, hydrogen sulfide, and methylmercaptons.

  7. Pure optical photoacoustic microscopy

    PubMed Central

    Xie, Zhixing; Chen, Sung-Liang; Ling, Tao; Guo, L. Jay; Carson, Paul L.; Wang, Xueding

    2011-01-01

    The concept of pure optical photoacoustic microscopy(POPAM) was proposed based on optical rastering of a focused excitation beam and optically sensing the photoacoustic signal using a microring resonator fabricated by a nanoimprinting technique. After the refinements of the microring’s working wavelength and in the resonator structure and mold fabrication, an ultrahigh Q factor of 3.0×105 was achieved which provided high sensitivity with a noise equivalent detectable pressure(NEDP) value of 29Pa. This NEDP is much lower than the hundreds of Pascals achieved with existing optical resonant structures such as etalons, fiber gratings and dielectric multilayer interference filters available for acoustic measurement. The featured high sensitivity allowed the microring resonator to detect the weak photoacoustic signals from micro- or submicroscale objects. The inherent superbroad bandwidth of the optical microring resonator combined with an optically focused scanning beam provided POPAM with high resolution in the axial as well as both lateral directions while the axial resolution of conventional photoacoustic microscopy (PAM) suffers from the limited bandwidth of PZT detectors. Furthermore, the broadband microring resonator showed similar sensitivity to that of our most sensitive PZT detector. The current POPAM system provides a lateral resolution of 5 μm and an axial resolution of 8 μm, comparable to that achieved by optical microscopy while presenting the unique contrast of optical absorption and functional information complementing other optical modalities. The 3D structure of microvasculature, including capillary networks, and even individual red blood cells have been discerned successfully in the proof-of-concept experiments on mouse bladders ex vivo and mouse ears in vivo. The potential of approximately GHz bandwidth of the microring resonator also might allow much higher resolution than shown here in microscopy of optical absorption and acoustic propagation

  8. High-Precision Measurement of The Oxygen Isotopic Composition of Tropospheric O2: Implications for Δ17O of air as a Biosignature

    NASA Astrophysics Data System (ADS)

    Young, E. D.; Ziegler, K.

    2006-05-01

    Here we present high-precision measurements of 18O/16O and 17O/16O in samples of tropospheric O2 using a standard calibrated with measurements of terrestrial and extraterrestrial rock samples. These new data provide a measure of Δ17O on an absolute scale that aids in the interpretation of the cause of the disparity in Δ17O between O2 in the troposphere and terrestrial rocks. We measured the isotopic composition of four separate aliquotes of ground-level air O2. Oxygen was isolated from air cryogenically using molecular sieve substrates. Correction was made for the influence of Ar scattered across the Faraday collectors (~0.06 per mil in δ17O) of the gas- source mass spectrometer. The reference gas used as an internal standard was calibrated against terrestrial rock samples and meteorites analyzed using infrared laser heating fluorination. All results are reported as linearized delta values (signified with a prime superscript symbol). With a mean terrestrial rock Δ17O'of 0.00 ‰ ± 0.02 we obtain Δ17O values of -0.25 ‰ ± 0.04 1σ, -0.22 ‰ ± 0.03, and -0.23 ‰ ± 0.05 for 5 mesosiderite meteorites, 7 pallasites, and 12 HED meteorites, respectively. The latter meteorite data are consistent with results from three other laboratories and serve to establish the absolute scale for the air O2 measurements. Our results for the O2 samples give a mean linearized δ18O' of 23.237 ‰ ± 0.008 1 std err (corresponding to a normal, non-linearized δ18O SMOW value of 23.509 ‰), a mean δ17O' of 11.922 ‰ ± 0.018, and a mean linearized Δ17O' of -0.347 ‰ ± 0.018 based on a rock-water terrestrial fractionation reference line with a slope (β) of 0.528. The latter is the exponent in a normal fractionation law described by the relation α17=(α18)β. This result can be reconciled with the suggestion by Young et al (2002) that the whole of the departure in Δ17O' of tropospheric O2 relative to terrestrial rocks can be attributed to respiration (a Δ17O Dole effect

  9. Batteries: Avoiding oxygen

    NASA Astrophysics Data System (ADS)

    Hardwick, Laurence J.

    2016-08-01

    In the development of lithium–air batteries, managing the phase change between gaseous oxygen and crystalline lithium peroxide is a key challenge. Now, a high-performing sealed battery with an oxygen anion-redox electrode is presented that does not involve any gas evolution.

  10. Who Needs Oxygen Therapy?

    MedlinePlus

    ... a progressive disease in which damage to the air sacs prevents them from moving enough oxygen into the bloodstream. "Progressive" means the disease gets worse over time. Late-stage heart failure . This is a condition in which the heart can't pump enough oxygen-rich blood to meet the body's ...

  11. The effect of collisional quenching of the O 3p 3PJ state on the determination of the spatial distribution of the atomic oxygen density in an APPJ operating in ambient air by TALIF

    NASA Astrophysics Data System (ADS)

    Zhang, S.; van Gessel, A. F. H.; van Grootel, S. C.; Bruggeman, P. J.

    2014-04-01

    The spatial profile of the absolute atomic oxygen density is obtained by two-photon absorption laser-induced fluorescence (TALIF) in an Ar+2% air cold atmospheric pressure plasma jet (APPJ) operating in ambient air. The varying air concentration in the jet effluent which contributes to the collisional quenching of the O 3p 3PJ state, pumped by the laser, strongly influences the recorded TALIF signal under the present experimental conditions. The spatially resolved air densities obtained from Raman scattering measurements have been reported in our previous work (van Gessel et al 2013 Appl. Phys. Lett. 103 064103). These densities allow us to calculate the spatially dependent collisional quenching rate for the O 3p 3PJ state and reconstruct the spatial O density profile from the recorded TALIF signal. Significant differences between the TALIF intensity profile and the actual O density profile for the investigated experimental conditions are found.

  12. Development of ITM oxygen technology for integration in IGCC and other advanced power generation

    SciTech Connect

    Armstrong, Phillip A.

    2015-03-31

    Ion Transport Membrane (ITM) technology is based on the oxygen-ion-conducting properties of certain mixed-metal oxide ceramic materials that can separate oxygen from an oxygen-containing gas, such as air, under a suitable driving force. The “ITM Oxygen” air separation system that results from the use of such ceramic membranes produces a hot, pure oxygen stream and a hot, pressurized, oxygen-depleted stream from which significant amounts of energy can be extracted. Accordingly, the technology integrates well with other high-temperature processes, including power generation. Air Products and Chemicals, Inc., the Recipient, in conjunction with a dozen subcontractors, developed ITM Oxygen technology under this five-phase Cooperative Agreement from the laboratory bench scale to implementation in a pilot plant capable of producing power and 100 tons per day (TPD) of purified oxygen. A commercial-scale membrane module manufacturing facility (the “CerFab”), sized to support a conceptual 2000 TPD ITM Oxygen Development Facility (ODF), was also established and operated under this Agreement. In the course of this work, the team developed prototype ceramic production processes and a robust planar ceramic membrane architecture based on a novel ceramic compound capable of high oxygen fluxes. The concept and feasibility of the technology was thoroughly established through laboratory pilot-scale operations testing commercial-scale membrane modules run under industrial operating conditions with compelling lifetime and reliability performance that supported further scale-up. Auxiliary systems, including contaminant mitigation, process controls, heat exchange, turbo-machinery, combustion, and membrane pressure vessels were extensively investigated and developed. The Recipient and subcontractors developed efficient process cycles that co-produce oxygen and power based on compact, low-cost ITMs. Process economics assessments show significant benefits relative to state

  13. Oxygen Transport Membranes

    SciTech Connect

    S. Bandopadhyay

    2008-08-30

    The focus of this research was to develop new membrane materials by synthesizing different compounds and determining their defect structures, crystallographic structures and electrical properties. In addition to measuring electrical conductivity, oxygen vacancy concentration was also evaluated using thermogravimetry, Neutron diffraction and Moessbauer Spectroscopy. The reducing conditions (CO{sub 2}/CO/H{sub 2} gas mixtures with steam) as encountered in a reactor environment can be expected to have significant influence on the mechanical properties of the oxides membranes. Various La based materials with and without Ti were selected as candidate membrane materials for OTM. The maximum electrical conductivity of LSF in air as a function of temperature was achieved at < 600 C and depends on the concentration of Sr (acceptor dopant). Oxygen occupancy in LSF was estimated using Neutron diffractometry and Moessbauer Spectroscopy by measuring magnetic moment changes depending on the Fe{sup 3+} and Fe{sup 4+} ratio. After extensive studies of candidate materials, lanthanum ferrites (LSF and LSFT) were selected as the favored materials for the oxygen transport membrane (OTM). LSF is a very good material for an OTM because of its high electronic and oxygen ionic conductivity if long term stability and mechanical strength are improved. LSFT not only exhibits p-type behavior in the high oxygen activity regime, but also has n-type conduction in reducing atmospheres. Higher concentrations of oxygen vacancies in the low oxygen activity regime may improve the performance of LSFT as an OTM. The hole concentration is related to the difference in the acceptor and donor concentration by the relation p = [Sr'{sub La}]-[Ti{sm_bullet}{sub Fe}]. The chemical formulation predicts that the hole concentration is, p = 0.8-0.45 or 0.35. Experimental measurements indicated that p is about {approx} 0.35. The activation energy of conduction is 0.2 eV which implies that LSCF conducts via the

  14. Detonability of hydrocarbon fuels in air

    NASA Technical Reports Server (NTRS)

    Beeson, H. D.; Mcclenagan, R. D.; Bishop, C. V.; Benz, F. J.; Pitz, W. J.; Westbrook, C. K.; Lee, J. H. S.

    1991-01-01

    Studies were conducted of the detonation of gas-phase mixtures of n-hexane and JP-4, with oxidizers as varied as air and pure oxygen, measuring detonation velocities and cell sizes as a function of stoichiometry and diluent concentration. The induction length of a one-dimensional Zeldovich-von Neumann-Doering detonation was calculated on the basis of a theoretical model that employed the reaction kinetics of the hydrocarbon fuels used. Critical energy and critical tube diameter are compared for a relative measure of the heavy hydrocarbon fuels studied; detonation sensitivity appears to increase slightly with increasing carbon number.

  15. Oxygenative and Dehydrogenative [3 + 3] Benzannulation Reactions of α,β-Unsaturated Aldehydes and γ-Phosphonyl Crotonates Mediated by Air: Regioselective Synthesis of 4-Hydroxybiaryl-2-carboxylates.

    PubMed

    Joshi, Prabhakar Ramchandra; Nanubolu, Jagadeesh Babu; Menon, Rajeev S

    2016-02-19

    Regioselective synthesis of 4-hydroxybiphenyl-2-carboxylates via the base-mediated oxygenative [3 + 3] benzannulation reaction of α,β-unsaturated aldehydes and γ-phosphonyl crotonates is reported. A hydroxyl group is installed in the final product on the originally phosphorus-bound carbon via a novel oxygenative and dehydrogenative transformation. The reaction proceeds rapidly in an open flask, uses atmospheric oxygen as an oxidant, and affords good yields of substituted biaryl phenols. PMID:26859060

  16. Randomised trial of ambulatory oxygen in oxygen-dependent COPD.

    PubMed

    Lacasse, Y; Lecours, R; Pelletier, C; Bégin, R; Maltais, F

    2005-06-01

    Long-term oxygen therapy may limit a patient's ability to remain active and may be detrimental to the rehabilitation process. This study aimed to determine the effect of ambulatory oxygen on quality of life and exercise capacity in patients with chronic obstructive pulmonary disease fulfilling the usual criteria of long-term oxygen therapy. In a 1-yr, randomised, three-period, crossover trial, 24 patients (mean age 68 yrs; mean arterial partial pressure of oxygen at rest 7.1 kPa (53 mmHg)) were allocated to one of the six possible sequences generated by three interventions: 1) standard therapy (home oxygen therapy with an oxygen concentrator only); 2) standard therapy plus as-needed ambulatory oxygen; and 3) standard therapy plus ambulatory compressed air. The comparison of ambulatory oxygen versus ambulatory compressed air was double blind. The main outcomes were quality of life (Chronic Respiratory Questionnaire), exercise tolerance (6-min walk test) and daily duration of exposure to oxygen therapy. The trial was stopped prematurely after an interim analysis. On average, the patients used few ambulatory cylinders (7.5 oxygen cylinders versus 7.4 compressed air cylinders over a 3-month study period). Ambulatory oxygen had no effect on any of the outcomes. In conclusion, the current results do not support the widespread provision of ambulatory oxygen to patients with oxygen-dependent chronic obstructive pulmonary disease. PMID:15929958

  17. Underwater loudness for pure tones: Duration effects

    NASA Astrophysics Data System (ADS)

    Cudahy, Edward A.; Schwaller, Derek; Fothergill, David; Wolgemuth, Keith

    2003-04-01

    The loudness of underwater pure tones was measured by loudness matching for pure tones from 100 to 16,000 Hz. The standard was a one second tone at 1000 Hz. The signal duration was varied from 20 milliseconds to 5 seconds. Subjects were instructed to match the loudness of the comparison tone at one of the test frequencies to the loudness of the standard tone. Loudness was measured at the threshold, the most comfortable loudness, and the maximum tolerable loudness. The intensity of the standard was varied randomly across the test series. The subjects were bareheaded U.S. Navy divers tested at a depth of 3 meters. All subjects had normal in-air hearing. Tones were presented to the right side of the subject from an array of underwater sound projectors. The sound pressure level was calibrated at the location of the subject's head with the subject absent. Loudness increased and threshold decreased as duration increased. The effect was greatest at the lowest and highest frequencies. The shape of the loudness contours across frequency and duration derived from these measurements are different from in-air measurements. [Research supported by ONR.

  18. Lithium-oxygen batteries-Limiting factors that affect performance

    NASA Astrophysics Data System (ADS)

    Padbury, Richard; Zhang, Xiangwu

    2011-05-01

    Lithium-oxygen batteries have recently received attention due to their extremely high theoretical energy densities, which far exceed that of any other existing energy storage technology. The significantly larger theoretical energy density of the lithium-oxygen batteries is due to the use of a pure lithium metal anode and the fact that the cathode oxidant, oxygen, is stored externally since it can be readily obtained from the surrounding air. Before the lithium-oxygen batteries can be realized as high performance, commercially viable products, there are still many challenges to overcome, from designing their cathode structure, to optimizing their electrolyte compositions and elucidating the complex chemical reactions that occur during charge and discharge. The scientific obstacles that are related to the performance of the lithium-oxygen batteries open up an exciting opportunity for researchers from many different backgrounds to utilize their unique knowledge and skills to bridge the knowledge gaps that exist in current research projects. This article is a summary of the most significant limiting factors that affect the performance of the lithium-oxygen batteries from the perspective of the authors. The article indicates the relationships that form between various limiting factors and highlights the complex yet captivating nature of the research within this field.

  19. Box-modeling of bone and tooth phosphate oxygen isotope compositions as a function of environmental and physiological parameters.

    PubMed

    Langlois, C; Simon, L; Lécuyer, Ch

    2003-12-01

    A time-dependent box model is developed to calculate oxygen isotope compositions of bone phosphate as a function of environmental and physiological parameters. Input and output oxygen fluxes related to body water and bone reservoirs are scaled to the body mass. The oxygen fluxes are evaluated by stoichiometric scaling to the calcium accretion and resorption rates, assuming a pure hydroxylapatite composition for the bone and tooth mineral. The model shows how the diet composition, body mass, ambient relative humidity and temperature may control the oxygen isotope composition of bone phosphate. The model also computes how bones and teeth record short-term variations in relative humidity, air temperature and delta18O of drinking water, depending on body mass. The documented diversity of oxygen isotope fractionation equations for vertebrates is accounted for by our model when for each specimen the physiological and diet parameters are adjusted in the living range of environmental conditions. PMID:14711171

  20. 30 CFR 57.5015 - Oxygen deficiency.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Oxygen deficiency. 57.5015 Section 57.5015..., Physical Agents, and Diesel Particulate Matter Air Quality-Underground Only § 57.5015 Oxygen deficiency. Air in all active workings shall contain at least 19.5 volume percent oxygen....

  1. 30 CFR 57.5015 - Oxygen deficiency.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Oxygen deficiency. 57.5015 Section 57.5015..., Physical Agents, and Diesel Particulate Matter Air Quality-Underground Only § 57.5015 Oxygen deficiency. Air in all active workings shall contain at least 19.5 volume percent oxygen....

  2. 30 CFR 57.5015 - Oxygen deficiency.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Oxygen deficiency. 57.5015 Section 57.5015..., Physical Agents, and Diesel Particulate Matter Air Quality-Underground Only § 57.5015 Oxygen deficiency. Air in all active workings shall contain at least 19.5 volume percent oxygen....

  3. 30 CFR 57.5015 - Oxygen deficiency.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Oxygen deficiency. 57.5015 Section 57.5015..., Physical Agents, and Diesel Particulate Matter Air Quality-Underground Only § 57.5015 Oxygen deficiency. Air in all active workings shall contain at least 19.5 volume percent oxygen....

  4. 30 CFR 57.5015 - Oxygen deficiency.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Oxygen deficiency. 57.5015 Section 57.5015..., Physical Agents, and Diesel Particulate Matter Air Quality-Underground Only § 57.5015 Oxygen deficiency. Air in all active workings shall contain at least 19.5 volume percent oxygen....

  5. Advanced oxygen-separation membranes. Topical report, April 1989-September 1990

    SciTech Connect

    Wright, J.D.; Copeland, R.J.

    1990-09-01

    The value of oxygen in improving the economics of high-temperature, natural-gas-fired processes is calculated, and the size and characteristics of the markets where oxygen-enhanced combustion could improve natural gas utilization are analyzed. Next, the cost of existing oxygen-separation processes is surveyed. Together, these define an economic target which any new production technology must meet if it is to be accepted. The bulk of the report analyzes three membrane based processes for oxygen production: polymeric membranes, porous ceramic membranes, and oxygen ion conducting membranes. Polymeric membranes are a commercially available technology limited to the production of oxygen-enriched air (OEA). Porous ceramic membranes have higher fluxes, higher costs, and are also limited to the production of OEA. Solid electrolyte, oxygen ion conductors produce pure oxygen, are applicable at both the very small and very large scales, and can potentially be less expensive than current technologies. In order to achieve this, better oxygen ion conductors and/or thinner membranes are required and membrane costs must be reduced. Improved conductors and thinner membranes are a target for fundamental research, while reduced costs will come both from improved materials and the general growth of the high-performance ceramics industry.

  6. Synaptic devices based on purely electronic memristors

    NASA Astrophysics Data System (ADS)

    Pan, Ruobing; Li, Jun; Zhuge, Fei; Zhu, Liqiang; Liang, Lingyan; Zhang, Hongliang; Gao, Junhua; Cao, Hongtao; Fu, Bing; Li, Kang

    2016-01-01

    Memristive devices have been widely employed to emulate biological synaptic behavior. In these cases, the memristive switching generally originates from electrical field induced ion migration or Joule heating induced phase change. In this letter, the Ti/ZnO/Pt structure was found to show memristive switching ascribed to a carrier trapping/detrapping of the trap sites (e.g., oxygen vacancies or zinc interstitials) in ZnO. The carrier trapping/detrapping level can be controllably adjusted by regulating the current compliance level or voltage amplitude. Multi-level conductance states can, therefore, be realized in such memristive device. The spike-timing-dependent plasticity, an important Hebbian learning rule, has been implemented in this type of synaptic device. Compared with filamentary-type memristive devices, purely electronic memristors have potential to reduce their energy consumption and work more stably and reliably, since no structural distortion occurs.

  7. Effect of dissolved inorganic carbon on oxygen evolution and uptake by Chlamydomonas reinhardtii suspensions adapted to ambient and CO2-enriched air.

    PubMed

    Sültemeyer, D F; Klug, K; Fock, H P

    1987-01-01

    Mass spectrometric measurements of (16)O2 and (18)O2 isotopes were used to compare the rates of gross O2 evolution (E0), O2 uptake (U0) and net O2 evolution (NET) in relation to different concentrations of dissolved inorganic carbon (DIC) by Chlamydomonas reinhardtii cells grown in air (air-grown), in air enriched with 5% CO2 (CO2-grown) and by cells grown in 5% CO2 and then adapted to air for 6h (air-adapted).At a photon fluence rate (PFR) saturating for photosynthesis (700 μmol photons m(-2) s(-1)), pH=7.0 and 28°C, U0 equalled E0 at the DIC compensation point which was 10μM DIC for CO2-grown and zero for air-grown cells. Both E0 and U0 were strongly dependent on DIC and reached DIC saturation at 480 μM and 70 μM for CO2-grown and air-grown algae respectively. U0 increased from DIC compensation to DIC saturation. The U0 values were about 40 (CO2-grown), 165 (air-adapted) and 60 μmol O2 mg Chl(-1) h(-1) (air-grown). Above DIC compensation the U0/E0 ratios of air-adapted and air-grown algae were always higher than those of CO2-grown cells. These differences in O2 exchange between CO2- and air-grown algae seem to be inducable since air-adapted algae respond similarly to air-grown cells.For all algae, the rates of dark respiratory O2 uptake measured 5 min after darkening were considerably lower than the rates of O2 uptake just before darkening. The contribution of dark respiration, photorespiration and the Mehler reaction to U0 is discussed and the energy requirement of the inducable CO2/HCO3 (-) concentrating mechanism present in air-adapted and air-grown C. reinhardtii cells is considered. PMID:24435578

  8. Nanoporous Au: an unsupported pure gold catalyst?

    SciTech Connect

    Wittstock, A; Neumann, B; Schaefer, A; Dumbuya, K; Kuebel, C; Biener, M; Zielasek, V; Steinrueck, H; Gottfried, M; Biener, J; Hamza, A; B?umer, M

    2008-09-04

    The unique properties of gold especially in low temperature CO oxidation have been ascribed to a combination of various effects. In particular, particle sizes below a few nm and specific particle-support interactions have been shown to play important roles. On the contrary, recent reports revealed that monolithic nanoporous gold (npAu) prepared by leaching a less noble metal, such as Ag, out of the corresponding alloy can also exhibit remarkably high catalytic activity for CO oxidation, even though no support is present. Therefore, it was claimed to be a pure and unsupported gold catalyst. We investigated npAu with respect to its morphology, surface composition and catalytic properties. In particular, we studied the reaction kinetics for low temperature CO oxidation in detail taking mass transport limitation due to the porous structure of the material into account. Our results reveal that Ag, even if removed almost completely from the bulk, segregates to the surface resulting in surface concentrations of up to 10 at%. Our data suggest that this Ag plays a significant role in activation of molecular oxygen. Therefore, npAu should be considered as a bimetallic catalyst rather than a pure Au catalyst.

  9. Electrocatalyst for oxygen reduction

    NASA Technical Reports Server (NTRS)

    Swette, L. L. (Inventor)

    1971-01-01

    The performance and costs of an electrochemical catalyst as compared to a pure platinum catalyst is evaluated. The catalysts are used to reduce oxygen in low temperature alkaline fuel cells. The electrochemical catalyst is composed of silver and platinum and is dispersed in a resinous inert binder to provide a cell electrode. The results indicate the electrochemical catalyst is superior structurally to the platinum one for high current density operation, and is at least as active as the platinum catalyst in other operations.

  10. H.R. 1589: A Bill to amend the Clean Air Act to authorize the Administrator of the Environmental Protection Agency to grant a waiver of the oxygenated fuels requirement, and for other purposes. Introduced in the House of Representatives, One Hundred Third Congress, First Session, April 1, 1993

    SciTech Connect

    1993-12-31

    The report H.R. 1589 is a bill to amend the Clean Air Act to authorize the Administrator of the Environmental Protection Agency to grant a waiver of the oxygenated fuels requirement. The use of methy tertiary butyl ether oxygenated fuels is referred to as M-T-B-E oxygenated fuels and at issue is a risk assessment of the health hazards of these ethanol fuels, particularly at low temperatures.

  11. Rhenium-Oxygen Interactions at High Temperatures

    NASA Technical Reports Server (NTRS)

    Jacobson, Nathan S.; Myers, Dwight L.; Zhu, Dongming; Humphrey, Donald

    2000-01-01

    The reaction of pure rhenium metal with dilute oxygen/argon mixtures was studied from 600 to 1400 C. Temperature, oxygen pressure, and flow rates were systematically varied to determine the rate-controlling steps. At lower temperatures the oxygen/rhenium chemical reaction is rate limiting; at higher temperatures gas-phase diffusion of oxygen through the static boundary layer is rate limiting. At all temperatures post-reaction microstructures indicate preferential attack along certain crystallographic planes and defects.

  12. Make Liquid Oxygen in Your Class

    ERIC Educational Resources Information Center

    French, M. M. J.; Hibbert, Michael

    2010-01-01

    Oxygen is one of the component gases of air at room temperature, making up around 20% of the atmosphere. But can oxygen be liquified? This article details a method for making small amounts of liquid oxygen in the classroom if there is no access to a cylinder of compressed oxygen gas, and two methods for identifying the fact that it is liquid…

  13. Effects of carbon on oxygen reduction and evolution reactions of gas-diffusion air electrodes based on perovskite-type oxides

    NASA Astrophysics Data System (ADS)

    Nishio, Koji; Molla, Sergio; Okugaki, Tomohiko; Nakanishi, Shinji; Nitta, Iwao; Kotani, Yukinari

    2015-12-01

    Electrochemical properties of three perovskite oxides with different B-site elements, LaMnO3, La0.6Sr0.4FeO3 and LaNiO3, are examined with and without carbon using gas-diffusion electrodes, in comparison with our previous results on La0.5Sr0.5CoO3. Cyclic voltammetry studies reveal very low oxygen reduction current density of carbon-free perovskite oxides, indicating their poor catalytic activity on oxygen reduction reactions. By mixing carbon with perovskite oxides, the oxygen reduction current density is increased by about two orders. The results are consistent with the peroxide pathway mechanism in which the perovskite oxide is highly active on either electrochemical reduction or chemical decomposition. Electrochemical properties of a three-layered gas diffusion electrode demonstrate the peroxide pathway mechanism works even the perovskite oxide and the carbon exist in separate layers. Oxygen evolution reactions are prominently dependent on the oxide species and also on an addition of carbon. The electrode based on carbon-free LaNiO3 or La0.5Sr0.5CoO3 show moderate oxygen evolution activity, and the activity is further enhanced by an addition of carbon, while LaMnO3 and La0.6Sr0.4FeO3 show poor activity even with an addition of carbon.

  14. Turbulence in pure superfluid flow

    SciTech Connect

    Ashton, R.A.; Opatowsky, L.B.; Tough, J.T.

    1981-03-09

    A series of experiments is described which provide an unambiguous description of the steady-state properties of turbulence in pure superfluid flow. The turbulence is qualitatively different from that observed in counterflow but comparable to the homogeneous turbulence described by theory.

  15. Production of substantially pure fructose

    DOEpatents

    Hatcher, Herbert J.; Gallian, John J.; Leeper, Stephen A.

    1990-01-01

    A process is disclosed for the production of substantially pure fructose from sucrose-containing substrates. The process comprises converting the sucrose to levan and glucose, purifying the levan by membrane technology, hydrolyzing the levan to form fructose monomers, and recovering the fructose.

  16. NORTH SIDES OF LIQUID OXYGEN TANKS. Looking southwest along railroad ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    NORTH SIDES OF LIQUID OXYGEN TANKS. Looking southwest along railroad track to AF Plant 72 - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Liquid Oxygen & Nitrogen Storage Tank Farm, Intersection of Altair & Jupiter Boulevards, Boron, Kern County, CA

  17. Natural Ores as Oxygen Carriers in Chemical Looping Combustion

    SciTech Connect

    Tian, Hanjing; Siriwardane, Ranjani; Simonyi, Thomas; Poston, James

    2013-08-01

    Chemical looping combustion (CLC) is a combustion technology that utilizes oxygen from oxygen carriers (OC), such as metal oxides, instead of air to combust fuels. The use of natural minerals as oxygen carriers has advantages, such as lower cost and availability. Eight materials, based on copper or iron oxides, were selected for screening tests of CLC processes using coal and methane as fuels. Thermogravimetric experiments and bench-scale fixed-bed reactor tests were conducted to investigate the oxygen transfer capacity, reaction kinetics, and stability during cyclic reduction/oxidation reaction. Most natural minerals showed lower combustion capacity than pure CuO/Fe{sub 2}O{sub 3} due to low-concentrations of active oxide species in minerals. In coal CLC, chryscolla (Cu-based), magnetite, and limonite (Fe-based) demonstrated better reaction performances than other materials. The addition of steam improved the coal CLC performance when using natural ores because of the steam gasification of coal and the subsequent reaction of gaseous fuels with active oxide species in the natural ores. In methane CLC, chryscolla, hematite, and limonite demonstrated excellent reactivity and stability in 50-cycle thermogravimetric analysis tests. Fe{sub 2}O{sub 3}-based ores possess greater oxygen utilization but require an activation period before achieving full performance in methane CLC. Particle agglomeration issues associated with the application of natural ores in CLC processes were also studied by scanning electron microscopy (SEM).

  18. Reactive Oxygen Species and Induction of Lignin Peroxidase in Phanerochaete chrysosporium

    PubMed Central

    Belinky, Paula A.; Flikshtein, Nufar; Lechenko, Sergey; Gepstein, Shimon; Dosoretz, Carlos G.

    2003-01-01

    We studied oxidative stress in lignin peroxidase (LIP)-producing cultures (cultures flushed with pure O2) of Phanerochaete chrysosporium by comparing levels of reactive oxygen species (ROS), cumulative oxidative damage, and antioxidant enzymes with those found in non-LIP-producing cultures (cultures grown with free exchange of atmospheric air [control cultures]). A significant increase in the intracellular peroxide concentration and the degree of oxidative damage to macromolecules, e.g., DNA, lipids, and proteins, was observed when the fungus was exposed to pure O2 gas. The specific activities of manganese superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidase and the consumption of glutathione were all higher in cultures exposed to pure O2 (oxygenated cultures) than in cultures grown with atmospheric air. Significantly higher gene expression of the LIP-H2 isozyme occurred in the oxygenated cultures. A hydroxyl radical scavenger, dimethyl sulfoxide (50 mM), added to the culture every 12 h, completely abolished LIP expression at the mRNA and protein levels. This effect was confirmed by in situ generation of hydroxyl radicals via the Fenton reaction, which significantly enhanced LIP expression. The level of intracellular cyclic AMP (cAMP) was correlated with the starvation conditions regardless of the oxygenation regimen applied, and similar cAMP levels were obtained at high O2 concentrations and in cultures grown with atmospheric air. These results suggest that even though cAMP is a prerequisite for LIP expression, high levels of ROS, preferentially hydroxyl radicals, are required to trigger LIP synthesis. Thus, the induction of LIP expression by O2 is at least partially mediated by the intracellular ROS. PMID:14602606

  19. Eggplant-derived microporous carbon sheets: towards mass production of efficient bifunctional oxygen electrocatalysts at low cost for rechargeable Zn-air batteries.

    PubMed

    Li, Bing; Geng, Dongsheng; Lee, Xinjing Shannon; Ge, Xiaoming; Chai, Jianwei; Wang, Zhijuan; Zhang, Jie; Liu, Zhaolin; Hor, T S Andy; Zong, Yun

    2015-05-25

    We report 2D microporous carbon sheets with high surface area, derived from eggplant via simple carbonization and KOH activation, as low cost yet efficient bifunctional catalysts for high performance rechargeable zinc-air batteries. PMID:25920952

  20. AIR RADIOACTIVITY MONITOR

    DOEpatents

    Bradshaw, R.L.; Thomas, J.W.

    1961-04-11

    The monitor is designed to minimize undesirable background buildup. It consists of an elongated column containing peripheral electrodes in a central portion of the column, and conduits directing an axial flow of radioactively contaminated air through the center of the column and pure air through the annular portion of the column about the electrodes. (AEC)

  1. Calibration Of Oxygen Monitors

    NASA Technical Reports Server (NTRS)

    Zalenski, M. A.; Rowe, E. L.; Mcphee, J. R.

    1988-01-01

    Readings corrected for temperature, pressure, and humidity of air. Program for handheld computer developed to ensure accuracy of oxygen monitors in National Transonic Facility, where liquid nitrogen stored. Calibration values, determined daily, based on entries of data on barometric pressure, temperature, and relative humidity. Output provided directly in millivolts.

  2. Pure-tone birdsong by resonance filtering of harmonic overtones

    PubMed Central

    Beckers, Gabriël J. L.; Suthers, Roderick A.; Cate, Carel ten

    2003-01-01

    Pure-tone song is a common and widespread phenomenon in birds. The mechanistic origin of this type of phonation has been the subject of long-standing discussion. Currently, there are three hypotheses. (i) A vibrating valve in the avian vocal organ, the syrinx, generates a multifrequency harmonic source sound, which is filtered to a pure tone by a vocal tract filter (“source-filter” model, analogous to human speech production). (ii) Vocal tract resonances couple with a vibrating valve source, suppressing the normal production of harmonic overtones at this source (“soprano” model, analogous to human soprano singing). (iii) Pure-tone sound is produced as such by a sound-generating mechanism that is fundamentally different from a vibrating valve. Here we present direct evidence of a source-filter mechanism in the production of pure-tone birdsong. Using tracheal thermistors and air sac pressure cannulae, we recorded sound signals close to the syringeal sound source during spontaneous, pure-tone vocalizations of two species of turtledove. The results show that pure-tone dove vocalizations originate through filtering of a multifrequency harmonic sound source. PMID:12764226

  3. Canonical Thermal Pure Quantum State

    NASA Astrophysics Data System (ADS)

    Sugiura, Sho; Shimizu, Akira

    2013-07-01

    A thermal equilibrium state of a quantum many-body system can be represented by a typical pure state, which we call a thermal pure quantum (TPQ) state. We construct the canonical TPQ state, which corresponds to the canonical ensemble of the conventional statistical mechanics. It is related to the microcanonical TPQ state, which corresponds to the microcanonical ensemble, by simple analytic transformations. Both TPQ states give identical thermodynamic results, if both ensembles do, in the thermodynamic limit. The TPQ states corresponding to other ensembles can also be constructed. We have thus established the TPQ formulation of statistical mechanics, according to which all quantities of statistical-mechanical interest are obtained from a single realization of any TPQ state. We also show that it has great advantages in practical applications. As an illustration, we study the spin-1/2 kagome Heisenberg antiferromagnet.

  4. Electrolysis cell functions as water vapor dehumidifier and oxygen generator

    NASA Technical Reports Server (NTRS)

    Clifford, J. E.

    1971-01-01

    Water vapor is absorbed in hygroscopic electrolyte, and oxygen generated by absorbed water electrolysis at anode is added simultaneously to air stream. Cell applications include on-board aircraft oxygen systems, portable oxygen generators, oxygen concentration requirements, and commercial air conditioning and dehumidifying systems.

  5. Effects of Temperature, Oxygen Level, Ionic Strength, and pH on the Reaction of Benzene with Hydroxyl Radicals at the Air-Water Interface in Comparison to the Bulk Aqueous Phase.

    PubMed

    Heath, Aubrey A; Valsaraj, Kalliat T

    2015-08-01

    Atmospheric aerosols (e.g., fog droplets) are complex, multiphase mediums. Depending on location, time of day, and/or air mass source, there can be considerable variability within these droplets, relating to temperature, pH, and ionic strength. Due to the droplets' inherently small size, the reactions that occur within these droplets are determined by bulk aqueous phase and air-water interfacial conditions. In this study, the reaction of benzene and hydroxyl radicals is examined kinetically in a thin-film flow-tube reactor. By varying the aqueous volume (e.g., film thickness) along the length of the reactor, both bulk and interfacial reaction rates are measured from a single system. Temperature, pH, and ionic strength are varied to model conditions typical of fog events. Oxygen-poor conditions are measured to study oxygen's overall effect on the reaction pathway. Initial rate activation energies and the bulk aqueous phase and interfacial contributions to the overall rate constant are also obtained. PMID:26158391

  6. Screening of Novel Li-Air Battery Catalyst Materials by a Thin Film Combinatorial Materials Approach.

    PubMed

    Hauck, John G; McGinn, Paul J

    2015-06-01

    A combinatorial synthesis and high-throughput screening process was developed for the investigation of potential oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts for use as Li-air battery cathode materials. Libraries of discrete ternary metal alloy compositions were deposited via thin-film sputtering. The samples were electrochemically tested in parallel using cyclic voltammetry in O2-saturated KOH electrolyte. Compositions were ranked by ORR and OER onset potentials with respect to an internal Pt reference. Results from the Pt-Mn-Co, Cr-Mn-Co, Pd-Mn-Co, and Pd-Mn-Ru systems are reported. Many alloy compositions showed marked improvement in catalytic activity compared to pure Pt. Among the systems considered, Pt12Mn44Co44, Pd43Co57 and Pd36Mn28Ru36 in particular exhibited lower overpotentials for oxygen reactions, which occur at the cathode in Li-air batteries. PMID:25965839

  7. Work, heat, and oxygen cost

    NASA Technical Reports Server (NTRS)

    Webb, P.

    1973-01-01

    Human energy is discussed in terms of the whole man. The physical work a man does, the heat he produces, and the quantity of oxygen he takes from the air to combine with food, the fuel source of his energy, are described. The daily energy exchange, work and heat dissipation, oxygen costs of specific activities, anaerobic work, and working in space suits are summarized.

  8. OBSERVATIONS OF THE OXIDATION OF PURE AND SPUTTERED TANTALUM VIA DILATOMETRY

    EPA Science Inventory

    The oxidation of pure and sputtered tantalum foils was observed via dilatometry and weight gain measurements. Specimens were tested in both helium and laboratory air at isothermal temperatures ranging from 300 oC to 850 oC. Based on weight gain measurements of pure tantalum, it...

  9. A novel GC-MS method for rapid determination of headspace oxygen in vials of pharmaceutical formulations.

    PubMed

    Wu, Lianming; Shen, Xue-Ming; Liu, David Q

    2008-09-10

    A novel GC-MS method which requires small injection volumes was developed for fast and selective determination of headspace oxygen in pharmaceutical packages. This method does not require a specific GC column for separation of oxygen from other permanent gases such as nitrogen; instead it offers the advantage of using co-eluting nitrogen as the internal standard for quantifying oxygen in the headspace under electron ionization (EI, 70 eV) conditions. The relative ionization efficiency of oxygen to nitrogen, termed as ionization efficiency correction factor (IECF), can be measured using a control sample with known composition of oxygen and nitrogen such as the standard dry air used in this study. To avoid contamination, it is necessary to flush the syringe with pure helium. The measurements by the method are independent of the variations of sampling volumes. The determined headspace oxygen contents (R.S.D.<1%) in the containers of an investigational intravenous formulation using this method are consistent with the results obtained by an oxygen instrument at the manufacturing facility. The performance of the analytical approach was evaluated in the study of the container closure integrity at various storage conditions including upright and inverted orientations. The results suggest that there is no obvious oxygen penetration over 12 months. This method provides a convenient tool for measuring the levels of HS oxygen in vials of pharmaceutical formulations. PMID:18565713

  10. 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.

  11. Oxygen analyzer

    DOEpatents

    Benner, William H.

    1986-01-01

    An oxygen analyzer which identifies and classifies microgram quantities of oxygen in ambient particulate matter and for quantitating organic oxygen in solvent extracts of ambient particulate matter. A sample is pyrolyzed in oxygen-free nitrogen gas (N.sub.2), and the resulting oxygen quantitatively converted to carbon monoxide (CO) by contact with hot granular carbon (C). Two analysis modes are made possible: (1) rapid determination of total pyrolyzable oxygen obtained by decomposing the sample at 1135.degree. C., or (2) temperature-programmed oxygen thermal analysis obtained by heating the sample from room temperature to 1135.degree. C. as a function of time. The analyzer basically comprises a pyrolysis tube containing a bed of granular carbon under N.sub.2, ovens used to heat the carbon and/or decompose the sample, and a non-dispersive infrared CO detector coupled to a mini-computer to quantitate oxygen in the decomposition products and control oven heating.

  12. pureS2HAT: S 2HAT-based Pure E/B Harmonic Transforms

    NASA Astrophysics Data System (ADS)

    Grain, J.; Stompor, R.; Tristram, M.

    2011-10-01

    The pS2HAT routines allow efficient, parallel calculation of the so-called 'pure' polarized multipoles. The computed multipole coefficients are equal to the standard pseudo-multipoles calculated for the apodized sky maps of the Stokes parameters Q and U subsequently corrected by so-called counterterms. If the applied apodizations fullfill certain boundary conditions, these multipoles correspond to the pure multipoles. Pure multipoles of one type, i.e., either E or B, are ensured not to contain contributions from the other one, at least to within numerical artifacts. They can be therefore further used in the estimation of the sky power spectra via the pseudo power spectrum technique, which has to however correctly account for the applied apodization on the one hand, and the presence of the counterterms, on the other. In addition, the package contains the routines permitting calculation of the spin-weighted apodizations, given an input scalar, i.e., spin-0 window. The former are needed to compute the counterterms. It also provides routines for maps and window manipulations. The routines are written in C and based on the S2HAT library, which is used to perform all required spherical harmonic transforms as well as all inter-processor communication. They are therefore parallelized using MPI and follow the distributed-memory computational model. The data distribution patterns, pixelization choices, conventions etc are all as those assumed/allowed by the S2HAT library.

  13. 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

  14. How pure are your vesicles?

    PubMed

    Webber, Jason; Clayton, Aled

    2013-01-01

    We propose a straightforward method to estimate the purity of vesicle preparations by comparing the ratio of nano-vesicle counts to protein concentration, using tools such as the increasingly available NanoSight platform and a colorimetric protein assay such as the BCA-assay. Such an approach is simple enough to apply to every vesicle preparation within a given laboratory, assisting researchers as a routine quality control step. Also, the approach may aid in comparing/standardising vesicle purity across diverse studies, and may be of particular importance in evaluating vesicular biomarkers. We herein propose some criteria to aid in the definition of pure vesicles. PMID:24009896

  15. Production of substantially pure fructose

    SciTech Connect

    Hatcher, H.J.; Gallian, J.J.; Leeper, S.A.

    1990-05-22

    This patent describes a process for the production of a substantially pure product containing greater than 60% fructose. It comprises: combining a sucrose-containing substrate with effective amounts of a levansucrase enzyme preparation to form levan and glucose; purifying the levan by at least one of the following purification methods: ultrafiltration, diafiltration, hyperfiltration, reverse osmosis, liquid--liquid partition, solvent extraction, chromatography, and precipitation; hydrolyzing the levan to form fructose substantially free of glucose and sucrose; and recovering the fructose by at least one of the following recovery methods: hyperfiltration, reverse osmosis, evaporation, drying, crystallization, and chromatography.

  16. Synthesis of Enantiomerically Pure Anthracyclinones

    NASA Astrophysics Data System (ADS)

    Achmatowicz, Osman; Szechner, Barbara

    The anthracycline antibiotics are among the most important clinical drugs used in the treatment of human cancer. The search for new agents with improved therapeutic efficacy and reduced cardiotoxicity stimulated considerable efforts in the synthesis of new analogues. Since the biological activity of anthracyclines depends on their natural absolute configuration, various strategies for the synthesis of enantiomerically pure anthracyclinones (aglycones) have been developed. They comprise: resolution of racemic intermediate, incorporation of a chiral fragment derived from natural and non-natural chiral pools, asymmetric synthesis with the use of a chiral auxiliary or a chiral reagent, and enantioselective catalysis. Synthetic advances towards enantiopure anthracyclinones reported over the last 17 years are reviewed.

  17. Two-Stage Energy Thermalization Mechanism in Nanosecond Pulse Discharges in Air and Hydrogen-Air Mixtures

    NASA Astrophysics Data System (ADS)

    Shkurenkov, Ivan; Lanier, Suzanne; Adamovich, Igor; Lempert, Walter

    2014-10-01

    Time-resolved and spatially resolved rotational temperature measurements in air and H2-air, by purely rotational Coherent Anti-Stokes Raman Spectroscopy (CARS), are presented. The experimental results demonstrate high accuracy of pure rotational psec CARS for thermometry measurements at low partial pressures of oxygen in nonequilibrium plasmas. The results are compared with modeling calculations using a state-specific master equation kinetic model of reacting hydrogen-air plasmas, showing good agreement. The results demonstrate that energy thermalization and temperature rise in these plasmas occur in two stages, (i) ``rapid'' heating, occurring on the time scale τrapid ~ 0 . 1 --1 μs .atm, caused by collisional quenching of excited electronic states of N2 molecules by O2, and (ii) ``slow'' heating, on the time scale τslow ~ 10 --100 μs .atm, caused primarily by N2 vibrational relaxation by O atoms (in air) and by chemical energy release during partial oxidation of hydrogen (in H2-air. Both energy thermalization mechanisms have major implications for plasma assisted combustion and plasma flow control.

  18. Use of a micro programmable logic controller for oxygen monitoring and control in multiple tanks of a recirculating aquaculture system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In intensive recirculating aquaculture systems the use of supplemental oxygen, specifically pure liquid oxygen, increases the mass of fish that can be supported and eliminates oxygen as a major limiting factor to a system’s carrying capacity. The use of pure oxygen in a recirculating aquaculture sys...

  19. Sulfur recovery plant and process using oxygen

    SciTech Connect

    Palm, J.W.

    1989-07-18

    This patent describes a process for recovery of sulfur from a gaseous stream containing hydrogen sulfide. The process consists the steps of: introducing a thermal reaction mixture comprising the gaseous stream containing hydrogen sulfide, and an oxygen-enriched stream of air or pure oxygen into a combustion zone of a Claus furnace; combusting the thermal reaction mixture in the Claus furnace to thereby produce hot combustion gases comprising hydrogen sulfide, sulfur dioxide, carbon dioxide, water, and elemental sulfur; introducing the hot combustion gases into a Claus catalytic reactor; subjecting the hot combustion gases in the catalytic reactor to Claus reaction conditions in the presence of a Claus catalyst to thereby produce a Claus plant gaseous effluent stream comprising hydrogen sulfide, sulfur dioxide, carbon dioxide, water, and elemental sulfur; introducing the Claus plant gaseous effluent into a condenser to thereby produce liquid sulfur, which is recovered, and a gaseous condenser effluent, which comprises hydrogen sulfide, sulfur dioxide, carbon dioxide and water and which is divided into a recycle portion and a tailgas portion; converting substantially all sulfur species in the recycle portion of the gaseous condenser effluent to hydrogen sulfide to thereby form condenser effluent comprising hydrogen sulfide, carbon dioxide and water; removing water from the recycle portion of the condenser; and moderating the temperature in the Claus furnace by returning at least a portion of the dried recycle condenser, as a diluent stream, to a combustion zone of the Claus furnace.

  20. Sulfur recovery plant and process using oxygen

    SciTech Connect

    Palm, J.W.

    1989-01-17

    This patent describes a process for the recovery of sulfur from a gaseous stream containing hydrogen sulfide, the process comprising the steps of: (a) introducing a thermal reaction mixture comprising (1) the gaseous stream containing hydrogen sulfide, and (2) an oxygen-enriched stream of air or pure oxygen into a combustion zone of a Claus furnace; (b) combusting the thermal reaction mixture in the Claus furnace to thereby produce hot combustion gases comprising hydrogen sulfide, sulfur dioxide, carbon dioxide, water, and elemental sulfur; (c) introducing the hot combustion gases into a Claus catalytic reactor; (d) subjecting the hot combustion gases in the catalytic reactor to Claus reaction conditions in the presence of a Claus catalyst to thereby produce a Claus plant gaseous effluent stream comprising hydrogen sulfide, sulfur dioxide, carbon dioxide, water, and elemental sulfur; (e) introducing the Claus plant gaseous effluent into a condenser to thereby produce liquid sulfur, which is recovered, and a gaseous condenser effluent, which comprises hydrogen sulfide, sulfur dioxide, carbon dioxide and water; (f) converting substantially all sulfur species in the gaseous condenser effluent to hydrogen sulfide, to thereby form a condenser effluent comprising hydrogen sulfide, carbon dioxide and water; (g) removing water from the condenser effluent from step (f); and (h) moderating the temperature in the Claus furnace by returning at least a portion of the dried condenser effluent from step (g), as a diluent stream, to a combustion zone of the Claus furnace in step (a) above.

  1. Oxygen analyzer

    DOEpatents

    Benner, W.H.

    1984-05-08

    An oxygen analyzer which identifies and classifies microgram quantities of oxygen in ambient particulate matter and for quantitating organic oxygen in solvent extracts of ambient particulate matter. A sample is pyrolyzed in oxygen-free nitrogen gas (N/sub 2/), and the resulting oxygen quantitatively converted to carbon monoxide (CO) by contact with hot granular carbon (C). Two analysis modes are made possible: (1) rapid determination of total pyrolyzable obtained by decomposing the sample at 1135/sup 0/C, or (2) temperature-programmed oxygen thermal analysis obtained by heating the sample from room temperature to 1135/sup 0/C as a function of time. The analyzer basically comprises a pyrolysis tube containing a bed of granular carbon under N/sub 2/, ovens used to heat the carbon and/or decompose the sample, and a non-dispersive infrared CO detector coupled to a mini-computer to quantitate oxygen in the decomposition products and control oven heating.

  2. Multiple pure tone noise prediction

    NASA Astrophysics Data System (ADS)

    Han, Fei; Sharma, Anupam; Paliath, Umesh; Shieh, Chingwei

    2014-12-01

    This paper presents a fully numerical method for predicting multiple pure tones, also known as “Buzzsaw” noise. It consists of three steps that account for noise source generation, nonlinear acoustic propagation with hard as well as lined walls inside the nacelle, and linear acoustic propagation outside the engine. Noise generation is modeled by steady, part-annulus computational fluid dynamics (CFD) simulations. A linear superposition algorithm is used to construct full-annulus shock/pressure pattern just upstream of the fan from part-annulus CFD results. Nonlinear wave propagation is carried out inside the duct using a pseudo-two-dimensional solution of Burgers' equation. Scattering from nacelle lip as well as radiation to farfield is performed using the commercial solver ACTRAN/TM. The proposed prediction process is verified by comparing against full-annulus CFD simulations as well as against static engine test data for a typical high bypass ratio aircraft engine with hardwall as well as lined inlets. Comparisons are drawn against nacelle unsteady pressure transducer measurements at two axial locations as well as against near- and far-field microphone array measurements outside the duct. This is the first fully numerical approach (no experimental or empirical input is required) to predict multiple pure tone noise generation, in-duct propagation and far-field radiation. It uses measured blade coordinates to calculate MPT noise.

  3. The absence of ion-regulatory suppression in the gills of the aquatic air-breathing fish Trichogaster lalius during oxygen stress.

    PubMed

    Huang, Chun-Yen; Lin, Hsueh-Hsi; Lin, Cheng-Huang; Lin, Hui-Chen

    2015-01-01

    The strategy for most teleost to survive in hypoxic or anoxic conditions is to conserve energy expenditure, which can be achieved by suppressing energy-consuming activities such as ion regulation. However, an air-breathing fish can cope with hypoxic stress using a similar adjustment or by enhancing gas exchange ability, both behaviorally and physiologically. This study examined Trichogaster lalius, an air-breathing fish without apparent gill modification, for their gill ion-regulatory abilities and glycogen utilization under a hypoxic treatment. We recorded air-breathing frequency, branchial morphology, and the expression of ion-regulatory proteins (Na(+)/K(+)-ATPase and vacuolar-type H(+)-ATPase) in the 1(st) and 4(th) gills and labyrinth organ (LO), and the expression of glycogen utilization (GP, glycogen phosphorylase protein expression and glycogen content) and other protein responses (catalase, CAT; carbonic anhydrase II, CAII; heat shock protein 70, HSP70; hypoxia-inducible factor-1α, HIF-1α; proliferating cell nuclear antigen, PCNA; superoxidase dismutase, SOD) in the gills of T. lalius after 3 days in hypoxic and restricted conditions. No morphological modification of the 1(st) and 4(th) gills was observed. The air-breathing behavior of the fish and CAII protein expression both increased under hypoxia. Ion-regulatory abilities were not suppressed in the hypoxic or restricted groups, but glycogen utilization was enhanced within the groups. The expression of HIF-1α, HSP70 and PCNA did not vary among the treatments. Regarding the antioxidant system, decreased CAT enzyme activity was observed among the groups. In conclusion, during hypoxic stress, T. lalius did not significantly reduce energy consumption but enhanced gas exchange ability and glycogen expenditure. PMID:25194989

  4. Oxygen incorporation into GST phase-change memory matrix

    NASA Astrophysics Data System (ADS)

    Golovchak, R.; Choi, Y. G.; Kozyukhin, S.; Chigirinsky, Yu.; Kovalskiy, A.; Xiong-Skiba, P.; Trimble, J.; Pafchek, R.; Jain, H.

    2015-03-01

    Structural changes in amorphous and crystallized GST-225 films induced by the reaction with oxygen are studied at different depth scales. The mechanism of interaction of the very top surface layers with oxygen is studied with low-energy ion scattering (LEIS) technique, while the modifications of chemistry in the underlying surface layers are investigated with high-resolution X-ray photoelectron spectroscopy (XPS). The changes averaged through the overall film thickness are characterized by micro-Raman spectroscopy. The oxygen exposure leads to a depletion of GST-225 film surfaces in Te and formation of the antimony and germanium oxides. The antimony oxide complexes are found throughout the whole thickness of the films after their prolonged storage in air, whereas no evidence for formation of pure GeO2 phase is found in the volume of the films through Raman spectroscopy. A tendency to form Ge-rich phase within the ∼10 nm surface layer is additionally observed by LEIS profiling during crystallization of GST-225 film at 300 °C in oxygen atmosphere.

  5. Oxidation behavior of V-Cr-Ti alloys in low-partial-pressure oxygen environments

    SciTech Connect

    Natesan, K.; Uz, M.

    1998-09-01

    A test program is in progress at Argonne National Laboratory to evaluate the effect of pO{sub 2} in the exposure environment on oxygen uptake, scaling kinetics, and scale microstructure in V-Cr-Ti alloys. The data indicate that the oxidation process follows parabolic kinetics in all of the environments used in the present study. From the weight change data, parabolic rate constants were evaluated as a function of temperature and exposure environment. The temperature dependence of the parabolic rate constants was described by an Arrhenius relationship. Activation energy for the oxidation process was fairly constant in the oxygen pressure range of 1 {times} 10{sup {minus}6} to 1 {times} 10{sup {minus}1} torr for both the alloys. The activation energy for oxidation in air was significantly lower than in low-pO{sub 2} environments, and for oxidation in pure O{sub 2} at 760 torr was much lower than in low-pO{sub 2} environments. X-ray diffraction analysis of the specimens showed that VO{sub 2} was the dominant phase in low-pO{sub 2} environments, while V{sub 2}O{sub 5} was dominant in air and in pure oxygen at 76f0 torr.

  6. The oxycoal process with cryogenic oxygen supply.

    PubMed

    Kather, Alfons; Scheffknecht, Günter

    2009-09-01

    Due to its large reserves, coal is expected to continue to play an important role in the future. However, specific and absolute CO2 emissions are among the highest when burning coal for power generation. Therefore, the capture of CO2 from power plants may contribute significantly in reducing global CO2 emissions. This review deals with the oxyfuel process, where pure oxygen is used for burning coal, resulting in a flue gas with high CO2 concentrations. After further conditioning, the highly concentrated CO2 is compressed and transported in the liquid state to, for example, geological storages. The enormous oxygen demand is generated in an air-separation unit by a cryogenic process, which is the only available state-of-the-art technology. The generation of oxygen and the purification and liquefaction of the CO2-enriched flue gas consumes significant auxiliary power. Therefore, the overall net efficiency is expected to be lowered by 8 to 12 percentage points, corresponding to a 21 to 36% increase in fuel consumption. Oxygen combustion is associated with higher temperatures compared with conventional air combustion. Both the fuel properties as well as limitations of steam and metal temperatures of the various heat exchanger sections of the steam generator require a moderation of the temperatures during combustion and in the subsequent heat-transfer sections. This is done by means of flue gas recirculation. The interdependencies among fuel properties, the amount and the temperature of the recycled flue gas, and the resulting oxygen concentration in the combustion atmosphere are investigated. Expected effects of the modified flue gas composition in comparison with the air-fired case are studied theoretically and experimentally. The different atmosphere resulting from oxygen-fired combustion gives rise to various questions related to firing, in particular, with regard to the combustion mechanism, pollutant reduction, the risk of corrosion, and the properties of the fly

  7. The oxycoal process with cryogenic oxygen supply

    NASA Astrophysics Data System (ADS)

    Kather, Alfons; Scheffknecht, Günter

    2009-09-01

    Due to its large reserves, coal is expected to continue to play an important role in the future. However, specific and absolute CO2 emissions are among the highest when burning coal for power generation. Therefore, the capture of CO2 from power plants may contribute significantly in reducing global CO2 emissions. This review deals with the oxyfuel process, where pure oxygen is used for burning coal, resulting in a flue gas with high CO2 concentrations. After further conditioning, the highly concentrated CO2 is compressed and transported in the liquid state to, for example, geological storages. The enormous oxygen demand is generated in an air-separation unit by a cryogenic process, which is the only available state-of-the-art technology. The generation of oxygen and the purification and liquefaction of the CO2-enriched flue gas consumes significant auxiliary power. Therefore, the overall net efficiency is expected to be lowered by 8 to 12 percentage points, corresponding to a 21 to 36% increase in fuel consumption. Oxygen combustion is associated with higher temperatures compared with conventional air combustion. Both the fuel properties as well as limitations of steam and metal temperatures of the various heat exchanger sections of the steam generator require a moderation of the temperatures during combustion and in the subsequent heat-transfer sections. This is done by means of flue gas recirculation. The interdependencies among fuel properties, the amount and the temperature of the recycled flue gas, and the resulting oxygen concentration in the combustion atmosphere are investigated. Expected effects of the modified flue gas composition in comparison with the air-fired case are studied theoretically and experimentally. The different atmosphere resulting from oxygen-fired combustion gives rise to various questions related to firing, in particular, with regard to the combustion mechanism, pollutant reduction, the risk of corrosion, and the properties of the fly

  8. Polymeric Materials Resistant to Erosion by Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Kiefer, Richard L.; Thibeault, Sheila A.

    2004-01-01

    Polymer-matrix composites are ideally suited for space vehicles because of high strength to weight ratios. The principal component of the low earth orbit (LEO) is atomic oxygen. Atomic oxygen causes surface erosion to polymeric materials. Polymer films with an organometallic additive showed greater resistance to atomic oxygen than the pure polymer in laboratory experiments and in the OPM/MIR experiment. In MISSE, the film with the organometallic additive was still intact after the pure film had completely eroded.

  9. Mathematical Modeling and Pure Mathematics

    ERIC Educational Resources Information Center

    Usiskin, Zalman

    2015-01-01

    Common situations, like planning air travel, can become grist for mathematical modeling and can promote the mathematical ideas of variables, formulas, algebraic expressions, functions, and statistics. The purpose of this article is to illustrate how the mathematical modeling that is present in everyday situations can be naturally embedded in…

  10. Monte Carlo simulation of electron detachment properties for {{\\text{O}_{2}^{{}}}^{-}} ions in oxygen and oxygen:nitrogen mixtures

    NASA Astrophysics Data System (ADS)

    Ponomarev, A. A.; Aleksandrov, N. L.

    2015-06-01

    Electron detachment properties of {{\\text{O}2{}}-} ions in pure oxygen and oxygen:nitrogen mixtures have been studied by a Monte Carlo technique for the reduced electric fields up to 350 Td (1 Td = 10-17 V·cm2). Swarm parameters were calculated for unexcited and vibrationally excited \\text{O}{{{}2}-} ions taking into account vibrational transfer and relaxation, charge transfer and electron detachment. The cross sections for vibrational transfer and relaxation in collisions between {{\\text{O}2{}}-} ions and O2 molecules were calculated on the basis of the statistical approach that had been successfully used in our previous work to simulate the effect of vibrational excitation and the effect of electric field on electron detachment. Good agreement between the calculated detachment rate and available measurements in oxygen were obtained over a wide range of reduced electric fields without using adjusted parameters. The method was used to calculate detachment rates in air and in some other oxygen:nitrogen mixtures and to study the effect of gas temperature on electron detachment.

  11. Neurological oxygen toxicity.

    PubMed

    Farmery, Scott; Sykes, Oliver

    2012-10-01

    SCUBA diving has several risks associated with it from breathing air under pressure--nitrogen narcosis, barotrauma and decompression sickness (the bends). Trimix SCUBA diving involves regulating mixtures of nitrogen, oxygen and helium in an attempt to overcome the risks of narcosis and decompression sickness during deep dives, but introduces other potential hazards such as hypoxia and oxygen toxicity convulsions. This study reports on a seizure during the ascent phase, its potential causes and management and discusses the hazards posed to the diver and his rescuer by an emergency ascent to the surface. PMID:21900296

  12. Hierarchically Porous Graphene as a Lithium-Air Battery Electrode

    SciTech Connect

    Xiao, Jie; Mei, Donghai; Li, Xiaolin; Xu, Wu; Wang, Deyu; Graff, Gordon L.; Bennett, Wendy D.; Nie, Zimin; Saraf, Laxmikant V.; Aksay, Ilhan A.; Liu, Jun; Zhang, Jiguang

    2011-11-09

    Functionalized graphene sheets (FGS) are successfully utilized as a novel air electrode for Li-O2 batteries. An extremely high capacity of 15,000 mAh/g was achieved by using the as-prepared graphene air electrode at a current density of 0.1 mA/cm2 in the pure oxygen environment. Although there is no pore in the two-dimensional FGS the as-prepared graphene air electrode consists of randomly arranged graphene nano-sheets which automatically form tunnels with different sizes. The large tunnels work as highways for the oxygen to quickly flow into the air electrode while the small pore-like tunnels can be considered as the numerous exits where the discharge products are accumulated. Combined with an appropriate electrolyte, the ideal discharge product Li2O2 is obtained without any carbonates byproducts in this system. Even when operated in ambient environment with a relative humidity of ~20% the specific capacity delivered from the pouch type cell achieves more than 5000 mAh/g making the graphene-based air electrode extremely attractive in the energy storage applications.

  13. Mass spectrometers and atomic oxygen

    NASA Technical Reports Server (NTRS)

    Hunton, D. E.; Trzcinski, E.; Cross, J. B.; Spangler, L. H.; Hoffbauer, M. H.; Archuleta, F. H.; Visentine, J. T.

    1987-01-01

    The likely role of atmospheric atomic oxygen in the recession of spacecraft surfaces and in the shuttle glow has revived interest in the accurate measurement of atomic oxygen densities in the upper atmosphere. The Air Force Geophysics Laboratory is supplying a quadrupole mass spectrometer for a materials interactions flight experiment being planned by the Johnson Space Center. The mass spectrometer will measure the flux of oxygen on test materials and will also identify the products of surface reactions. The instrument will be calibrated at a new facility for producing high energy beams of atomic oxygen at the Los Alamos National Laboratory. The plans for these calibration experiments are summarized.

  14. Simplified Two-Time Step Method for Calculating Combustion Rates and Nitrogen Oxide Emissions for Hydrogen/Air and Hydorgen/Oxygen

    NASA Technical Reports Server (NTRS)

    Molnar, Melissa; Marek, C. John

    2005-01-01

    A simplified single rate expression for hydrogen combustion and nitrogen oxide production was developed. Detailed kinetics are predicted for the chemical kinetic times using the complete chemical mechanism over the entire operating space. These times are then correlated to the reactor conditions using an exponential fit. Simple first order reaction expressions are then used to find the conversion in the reactor. The method uses a two-time step kinetic scheme. The first time averaged step is used at the initial times with smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, temperature, and pressure. The second instantaneous step is used at higher water concentrations (> 1 x 10(exp -20) moles/cc) in the mixture which gives the chemical kinetic time as a function of the instantaneous fuel and water mole concentrations, pressure and temperature (T4). The simple correlations are then compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. This time is regressed over the complete initial conditions using the Excel regression routine. Chemical kinetic time equations for H2 and NOx are obtained for H2/air fuel and for the H2/O2. A similar correlation is also developed using data from NASA s Chemical Equilibrium Applications (CEA) code to determine the equilibrium temperature (T4) as a function of overall fuel/air ratio, pressure and initial temperature (T3). High values of the regression coefficient R2 are obtained.

  15. Summary of Simplified Two Time Step Method for Calculating Combustion Rates and Nitrogen Oxide Emissions for Hydrogen/Air and Hydrogen/Oxygen

    NASA Technical Reports Server (NTRS)

    Marek, C. John; Molnar, Melissa

    2005-01-01

    A simplified single rate expression for hydrogen combustion and nitrogen oxide production was developed. Detailed kinetics are predicted for the chemical kinetic times using the complete chemical mechanism over the entire operating space. These times are then correlated to the reactor conditions using an exponential fit. Simple first order reaction expressions are then used to find the conversion in the reactor. The method uses a two time step kinetic scheme. The first time averaged step is used at the initial times with smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, temperature, and pressure. The second instantaneous step is used at higher water concentrations (greater than l x 10(exp -20)) moles per cc) in the mixture which gives the chemical kinetic time as a function of the instantaneous fuel and water mole concentrations, pressure and temperature (T(sub 4)). The simple correlations are then compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. This time is regressed over the complete initial conditions using the Excel regression routine. Chemical kinetic time equations for H2 and NOx are obtained for H2/Air fuel and for H2/O2. A similar correlation is also developed using data from NASA's Chemical Equilibrium Applications (CEA) code to determine the equilibrium temperature (T(sub 4)) as a function of overall fuel/air ratio, pressure and initial temperature (T(sub 3)). High values of the regression coefficient R squared are obtained.

  16. Pure optical dynamical color encryption.

    PubMed

    Mosso, Fabian; Tebaldi, Myrian; Barrera, John Fredy; Bolognini, Néstor; Torroba, Roberto

    2011-07-18

    We introduce a way to encrypt-decrypt a color dynamical phenomenon using a pure optical alternative. We split the three basic chromatic channels composing the input, and then each channel is processed through a 4f encoding method and a theta modulation applied to the each encrypted frame in every channel. All frames for a single channel are multiplexed. The same phase mask is used to encode all the information. Unlike the usual procedure we do not multiplex the three chromatic channels into a single encoding media, because we want to decrypt the information in real time. Then, we send to the decoding station the phase mask and the three packages each one containing the multiplexing of a single channel. The end user synchronizes and decodes the information contained in the separate channels. Finally, the decoding information is conveyed together to bring the decoded dynamical color phenomenon in real-time. We present material that supports our concepts. PMID:21934738

  17. Pure optical dynamical color encryption

    NASA Astrophysics Data System (ADS)

    Mosso, Fabian; Tebaldi, Myrian; Fredy Barrera, John; Bolognini, Néstor; Torroba, Roberto

    2011-07-01

    We introduce a way to encrypt-decrypt a color dynamical phenomenon using a pure optical alternative. We split the three basic chromatic channels composing the input, and then each channel is processed through a 4f encoding method and a theta modulation applied to the each encrypted frame in every channel. All frames for a single channel are multiplexed. The same phase mask is used to encode all the information. Unlike the usual procedure we do not multiplex the three chromatic channels into a single encoding media, because we want to decrypt the information in real time. Then, we send to the decoding station the phase mask and the three packages each one containing the multiplexing of a single channel. The end user synchronizes and decodes the information contained in the separate channels. Finally, the decoding information is conveyed together to bring the decoded dynamical color phenomenon in real-time. We present material that supports our concepts.

  18. Fuel cell serves as oxygen level detector

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Monitoring the oxygen level in the air is accomplished by a fuel cell detector whose voltage output is proportional to the partial pressure of oxygen in the sampled gas. The relationship between output voltage and partial pressure of oxygen can be calibrated.

  19. 76 FR 69284 - Pure Magnesium From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-08

    ... COMMISSION Pure Magnesium From China Determination On the basis of the record \\1\\ developed in the subject... order on pure magnesium from China would be likely to lead to continuation or recurrence of material... USITC Publication 4274 (October 2011), entitled Pure Magnesium from China: Investigation No....

  20. Mixed oxygen ion/electron-conducting ceramics for oxygen separation

    SciTech Connect

    Stevenson, J.W.; Armstrong, T.R.; Armstrong, B.L.

    1996-08-01

    Mixed oxygen ion and electron-conducting ceramics are unique materials that can passively separate high purity oxygen from air. Oxygen ions move through a fully dense ceramic in response to an oxygen concentration gradient, charge-compensated by an electron flux in the opposite direction. Compositions in the system La{sub 1{minus}x}M{sub x}Co{sub 1{minus}y{minus}z}Fe{sub y}N{sub z}O{sub 3{minus}{delta}}, perovskites where M=Sr, Ca, and Ba, and N=Mn, Ni, Cu, Ti, and Al, have been prepared and their electrical, oxygen permeation, oxygen vacancy equilibria, and catalytic properties evaluated. Tubular forms, disks, and asymmetric membrane structures, a thin dense layer on a porous support of the same composition, have been fabricated for testing purposes. In an oxygen partial gradient, the passive oxygen flux through fully dense structures was highly dependent on composition. An increase in oxygen permeation with increased temperature is attributed to both enhanced oxygen vacancy mobility and higher vacancy populations. Highly acceptor-doped compositions resulted in oxygen ion mobilities more than an order of magnitude higher than yttria-stabilized zirconia. The mixed conducting ceramics have been utilized in a membrane reactor configuration to upgrade methane to ethane and ethylene. Conditions were established to balance selectivity and throughput in a catalytic membrane reactor constructed from mixed conducting ceramics.

  1. Changes in breathing pattern upon 100% oxygen in children at early school age.

    PubMed

    Jost, K; Lenherr, N; Singer, F; Schulzke, S M; Frey, U; Latzin, P; Yammine, S

    2016-07-01

    Nitrogen multiple-breath washout (N2MBW) is an increasingly used tidal breathing test in young children to assess ventilation inhomogeneity. However, the test requires 100% oxygen to perform. We aimed to examine the potential influence of pure oxygen on breathing pattern in school-aged children. We performed tidal breathing measurements under room air followed by N2MBW in 16 former preterm children and 24 healthy controls. We compared tidal volume (VT), coefficient of variation of VT (CVVT), respiratory rate (RR), and minute ventilation (VE) between tidal breathing and N2MBW, and between the start and end of tidal breathing. Mean (range) age was 6.8 (5.9, 9.0) years. VT, RR and VE showed no significant change upon oxygen-exposure, while CVVT significantly decreased by 5% (95% CI: 1.2, 9.0; p=0.012). However CVVT was also the only parameter which significantly decreased during tidal breathing. Overall, pure oxygen has no systematic effect on breathing pattern in young school-aged children. N2MBW can reliably be used as tracer gas in this age group. PMID:26970571

  2. Decryption of pure-position permutation algorithms.

    PubMed

    Zhao, Xiao-Yu; Chen, Gang; Zhang, Dan; Wang, Xiao-Hong; Dong, Guang-Chang

    2004-07-01

    Pure position permutation image encryption algorithms, commonly used as image encryption investigated in this work are unfortunately frail under known-text attack. In view of the weakness of pure position permutation algorithm, we put forward an effective decryption algorithm for all pure-position permutation algorithms. First, a summary of the pure position permutation image encryption algorithms is given by introducing the concept of ergodic matrices. Then, by using probability theory and algebraic principles, the decryption probability of pure-position permutation algorithms is verified theoretically; and then, by defining the operation system of fuzzy ergodic matrices, we improve a specific decryption algorithm. Finally, some simulation results are shown. PMID:15495308

  3. Integrated oxygen recovery system

    NASA Technical Reports Server (NTRS)

    Lee, M. Gene; Davenport, Ronald J.

    1993-01-01

    Life Systems has conceptualized an innovative Integrated Oxygen Recovery System (IORS) applicable to advanced mission air revitalization. The IORS provides the capability to electrochemically generate metabolic oxygen (O2) and recover O2 from the space habitat atmosphere via a carbon dioxide (CO2) reduction process within a single assembly. To achieve this capability, the IORS utilizes a Solid Metal Cathode (SMC) water electrolysis unit that simultaneously serves as the Sabatier CO2 reduction reactor. The IORS enables two major life support systems currently baselined in closed loop air revitalization systems to be combined into one smaller, less complex system. This concept reduces fluidic and electrical interface requirements and eliminates a hydrogen (H2) interface. Life Systems is performing an evaluation of the IORS process directed at demonstrating performance and quantifying key physical characteristics including power, weight, and volume. The results of the checkout, shakedown, and initial parametric tests are summarized.

  4. Integrated oxygen recovery system

    NASA Technical Reports Server (NTRS)

    Lee, M. Gene; Davenport, Ronald J.

    1993-01-01

    Life Systems has conceptualized an innovative Integrated Oxygen Recovery System (IORS) applicable to advanced mission air revitalization. The IORS provides the capability to electrochemically generate metabolic oxygen (O2) and recover O2 from the space habitat atmosphere via a carbon dioxide (CO2) reduction process within a single assembly. To achieve this capability, the IORS utilizes a Solid Metal Cathode (SMC) water electrolysis unit that simultaneously serves as the Sabatier CO2 reduction reactor. The IORS enables two major life support systems currently baselined in closed loop air revitalization systems to be combined into one smaller, less complex system. This concept reduces fluidic and electrical interface requirements and eliminates a hydrogen (H2) interface. Life Systems is performing an evaluation of the IORS process directed at demonstrating performance and quantifying key physical characteristics including power, weight, and volume. Technical progress achieved during the first two months of the program is summarized.

  5. OXYGEN TRANSPORT CERAMIC MEMBRANES

    SciTech Connect

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2003-01-01

    In the present quarter, the possibility of using a more complex interfacial engineering approach to the development of reliable and stable oxygen transport perovskite ceramic membranes/metal seals is discussed. Experiments are presented and ceramic/metal interactions are characterized. Crack growth and fracture toughness of the membrane in the reducing conditions are also discussed. Future work regarding this approach is proposed are evaluated for strength and fracture in oxygen gradient conditions. Oxygen gradients are created in tubular membranes by insulating the inner surface from the reducing environment by platinum foils. Fracture in these test conditions is observed to have a gradient in trans and inter-granular fracture as opposed to pure trans-granular fracture observed in homogeneous conditions. Fracture gradients are reasoned to be due to oxygen gradient set up in the membrane, variation in stoichiometry across the thickness and due to varying decomposition of the parent perovskite. The studies are useful in predicting fracture criterion in actual reactor conditions and in understanding the initial evolution of fracture processes.

  6. Mixtures of maximally entangled pure states

    NASA Astrophysics Data System (ADS)

    Flores, M. M.; Galapon, E. A.

    2016-09-01

    We study the conditions when mixtures of maximally entangled pure states remain entangled. We found that the resulting mixed state remains entangled when the number of entangled pure states to be mixed is less than or equal to the dimension of the pure states. For the latter case of mixing a number of pure states equal to their dimension, we found that the mixed state is entangled provided that the entangled pure states to be mixed are not equally weighted. We also found that one can restrict the set of pure states that one can mix from in order to ensure that the resulting mixed state is genuinely entangled. Also, we demonstrate how these results could be applied as a way to detect entanglement in mixtures of the entangled pure states with noise.

  7. Environmental enhancement of creep crack growth in Inconel 718 by oxygen and water vapor

    SciTech Connect

    Valerio, P.; Gao, M.; Wei, R.P. . Dept. of Mechanical Engineering and Mechanics)

    1994-05-15

    Inconel 718 alloy is widely used in high temperature applications. Because of its sensitivity to environmentally enhanced crack growth at high temperatures, its use has been limited to modest temperatures (i.e., below 973 K). To improve its performance and to better predict its service life, it is important to develop a better understanding of the processes of crack growth at high temperatures in this alloy. It has been shown that the creep crack growth rates (CCGR) in air are at least two orders of magnitude faster than those in vacuum or inert environments. CCGR were also found to depend strongly on temperature. Fractographic studies showed that crack growth was intergranular in air and in vacuum with brittle appearing grain boundary separation in air and extensive cavity formation in vacuum. The increased CCGR in air has been attributed to the enhancement by oxygen; principally through enhanced cavity nucleation and growth by high-pressure carbon monoxide/dioxide formed by the reactions of oxygen that diffused into the material with the grain boundary carbides. The appropriateness of this mechanism, however, may be questioned by the absence of cavitation on the crack surfaces produced in air. As such the mechanism for crack growth needs to be re-examined. Because of the presence of moisture in air, the possible influence of hydrogen needs to be considered as well. In this study, preliminary experiments were conducted to examine the process of environmentally enhanced creep crack growth in Inconel 718 alloy in terms of possible mechanisms and rate controlling processes. Creep crack growth experiments were carried out in air, oxygen (from 2.67 to 100 kPa), moist argon (water vapor) and pure argon at temperatures from 873 to 973 K.

  8. Nitrated and oxygenated derivatives of polycyclic aromatic hydrocarbons in the ambient air of two French alpine valleys Part 2: Particle size distribution

    NASA Astrophysics Data System (ADS)

    Albinet, A.; Leoz-Garziandia, E.; Budzinski, H.; Villenave, E.; Jaffrezo, J.-L.

    The size distribution of polycyclic aromatic hydrocarbons (PAHs) and PAH derivatives was determined during the intensive sampling campaigns of the POVA (Pollution des Vallées Alpines) research programme, in two French alpine valleys, in winter and summer. The size distributions of PAHs, oxygenated PAHs (OPAHs) and nitrated PAHs (NPAHs) present large variations with year time and site type (traffic; suburban and rural). In general, these compounds were mainly associated (60-90%) with fine particles ( Dp<1.3 μm) in agreement with their release from sources (primary and/or secondary). The pollutant distributions with particle size were unimodal and centred at 0.85 μm both in the Chamonix and Maurienne valleys. The summer size distribution of NPAHs was centred at Dp=2.75 μm. PAH, OPAH and NPAH super micrometre fractions were significantly larger in summer for most sites suggesting the existence of a second mode in that particle size range. A possible reason to explain this phenomenon is that aerosol was locally polluted and characterised by fine particles in winter whereas in summer, aerosol was more mixed and older with possibilities of adsorption of gaseous organic compounds at the surface of the pre-exiting particles. In summer, NPAHs were associated to a greater degree with the super micrometre fraction of the aerosol than the other categories of compounds.

  9. Iron- and nitrogen-functionalized graphene as a non-precious metal catalyst for enhanced oxygen reduction in an air-cathode microbial fuel cell

    NASA Astrophysics Data System (ADS)

    Li, Sizhe; Hu, Yongyou; Xu, Qian; Sun, Jian; Hou, Bin; Zhang, Yaping

    2012-09-01

    In this work, iron- and nitrogen-functionalized graphene (Fe-N-G) as a non-precious metal catalyst is synthesized via a facile method of thermal treatment of a mixture of Fe salt, graphitic carbon nitride (g-C3N4) and chemically reduced graphene. The electrocatalytic activity of the prepared catalysts toward oxygen reduction reaction (ORR) evaluated by using linear sweep voltammetry tests shows that the Fe-N-G catalyst has more positive onset potential and increased reduction current densities as compared to the pristine graphene (P-G) catalyst, indicating an enhanced ORR activity of the Fe-N-G catalyst. More importantly, the Fe-N-G-MFC achieves the highest power density of 1149.8 mW m-2, which is ∼2.1 times of that generated with the Pt/C-MFC (561.1 mW m-2) and much higher than that of the P-G-MFC (109 mW m-2). These results demonstrate that the Fe-N-G catalyst can hold the promise of being an excellent alternative to the costly Pt catalyst for practical MFC applications.

  10. Appreciating Oxygen

    ERIC Educational Resources Information Center

    Weiss, Hilton M.

    2008-01-01

    Photosynthetic flora and microfauna utilize light from the sun to convert carbon dioxide and water into carbohydrates and oxygen. While these carbohydrates and their derivative hydrocarbons are generally considered to be fuels, it is the thermodynamically energetic oxygen molecule that traps, stores, and provides almost all of the energy that…

  11. Oxygen safety

    MedlinePlus

    ... Watch out for splattering grease. It can catch fire. Keep children with oxygen away from the stove top and oven. Cooking ... under the bed. Keep liquids that may catch fire away from your oxygen. This includes cleaning products that contain oil, grease, ...

  12. Recovery Act: Novel Oxygen Carriers for Coal-fueled Chemical Looping

    SciTech Connect

    Pan, Wei-Ping; Cao, Yan

    2012-11-30

    Chemical Looping Combustion (CLC) could totally negate the necessity of pure oxygen by using oxygen carriers for purification of CO{sub 2} stream during combustion. It splits the single fuel combustion reaction into two linked reactions using oxygen carriers. The two linked reactions are the oxidation of oxygen carriers in the air reactor using air, and the reduction of oxygen carriers in the fuel reactor using fuels (i.e. coal). Generally metal/metal oxides are used as oxygen carriers and operated in a cyclic mode. Chemical looping combustion significantly improves the energy conversion efficiency, in terms of the electricity generation, because it improves the reversibility of the fuel combustion process through two linked parallel processes, compared to the conventional combustion process, which is operated far away from its thermo-equilibrium. Under the current carbon-constraint environment, it has been a promising carbon capture technology in terms of fuel combustion for power generation. Its disadvantage is that it is less mature in terms of technological commercialization. In this DOE-funded project, accomplishment is made by developing a series of advanced copper-based oxygen carriers, with properties of the higher oxygen-transfer capability, a favorable thermodynamics to generate high purity of CO{sub 2}, the higher reactivity, the attrition-resistance, the thermal stability in red-ox cycles and the achievement of the auto-thermal heat balance. This will be achieved into three phases in three consecutive years. The selected oxygen carriers with final-determined formula were tested in a scaled-up 10kW coal-fueled chemical looping combustion facility. This scaled-up evaluation tests (2-day, 8-hour per day) indicated that, there was no tendency of agglomeration of copper-based oxygen carriers. Only trace-amount of coke or carbon deposits on the copper-based oxygen carriers in the fuel reactor. There was also no evidence to show the sulphidization of oxygen

  13. Bringing Planctomycetes into pure culture

    PubMed Central

    Lage, Olga M.; Bondoso, Joana

    2012-01-01

    Planctomycetes have been known since the description of Planctomyces bekefii by Gimesi at the beginning of the twentieth century (1924), although the first axenic cultures were only obtained in the 1970s. Since then, 11 genera with 14 species have been validly named and five candidatus genera belonging to the anaerobic ammonium oxidation, anammox bacteria have also been discovered. However, Planctomycetes diversity is much broader than these numbers indicate, as shown by environmental molecular studies. In recent years, the authors have attempted to isolate and cultivate additional strains of Planctomycetes. This paper provides a summary of the isolation work that was carried out to obtain in pure culture Planctomycetes from several environmental sources. The following strains of planctomycetes have been successfully isolated: two freshwater strains from the sediments of an aquarium, which were described as a new genus and species, Aquisphaera giovannonii; several Rhodopirellula strains from the sediments of a water treatment recycling tank of a marine fish farm; and more than 140 planctomycetes from the biofilm community of macroalgae. This collection comprises several novel taxa that are being characterized and described. Improvements in the isolation methodology were made in order to optimize and enlarge the number of Planctomycetes isolated from the macroalgae. The existence of an intimate and an important relationship between planctomycetes and macroalgae reported before by molecular studies is therefore supported by culture-dependent methods. PMID:23335915

  14. Isomerically Pure Tetramethylrhodamine Voltage Reporters.

    PubMed

    Deal, Parker E; Kulkarni, Rishikesh U; Al-Abdullatif, Sarah H; Miller, Evan W

    2016-07-27

    We present the design, synthesis, and application of a new family of fluorescent voltage indicators based on isomerically pure tetramethylrhodamines. These new Rhodamine Voltage Reporters, or RhoVRs, use photoinduced electron transfer (PeT) as a trigger for voltage sensing, display excitation and emission profiles in the green to orange region of the visible spectrum, demonstrate high sensitivity to membrane potential changes (up to 47% ΔF/F per 100 mV), and employ a tertiary amide derived from sarcosine, which aids in membrane localization and simultaneously simplifies the synthetic route to the voltage sensors. The most sensitive of the RhoVR dyes, RhoVR 1, features a methoxy-substituted diethylaniline donor and phenylenevinylene molecular wire at the 5'-position of the rhodamine aryl ring, exhibits the highest voltage sensitivity to date for red-shifted PeT-based voltage sensors, and is compatible with simultaneous imaging alongside green fluorescent protein-based indicators. The discoveries that sarcosine-based tertiary amides in the context of molecular-wire voltage indicators prevent dye internalization and 5'-substituted voltage indicators exhibit improved voltage sensitivity should be broadly applicable to other types of PeT-based voltage-sensitive fluorophores. PMID:27428174

  15. Hybrid Air-Electrode for Li/Air Batteries

    SciTech Connect

    Xiao, Jie; Xu, Wu; Wang, Deyu; Zhang, Jiguang

    2010-01-20

    A novel hybrid air-electrode is designed to improve the power density of Li/air batteries operating in an ambient environment. Three lithium insertion materials, MnO2, V2O5, and CFx (x = 1.0 to 1.15), are mixed with activated carbon to prepare different hybrid air-electrodes used in Li/air batteries. When compared with pure carbon-based Li/air batteries, the batteries using hybrid air-electrodes demonstrate significantly improved power capacities, especially for the CFx-based hybrid Li/air batteries. Because it is hydrophobic, CFx also facilitates the formation of air-flow channels in the carbon matrix, and alleviates air-electrode blocking problem during the discharge process. These hybrid air-electrodes provide a promising approach to improve the power density of Li/air batteries.

  16. Nitrated and oxygenated derivatives of polycyclic aromatic hydrocarbons in the ambient air of two French alpine valleys. Part 1: Concentrations, sources and gas/particle partitioning

    NASA Astrophysics Data System (ADS)

    Albinet, A.; Leoz-Garziandia, E.; Budzinski, H.; Villenave, E.; Jaffrezo, J.-L.

    Ambient measurements (gas+particle phases) of 16 polycyclic aromatic hydrocarbons, 17 nitrated PAHs (NPAHs) and eight oxygenated PAHs (OPAHs) were carried out during the winter 2002-2003 and the summer 2003 in two French alpine valleys on various types of sites (traffic, sub-urban, altitude and rural). Atmospheric concentrations of these classes of compounds are of interest because they include potential mutagens and carcinogens. During both summer and winter campaigns, OPAH concentration levels were of the same order of magnitude as PAH ones while NPAH concentrations were one to two orders of magnitude lower. Total particulate PAH, OPAH and NPAH concentrations were higher in the Chamonix valley than in the Maurienne valley. A heavier pollutant accumulation process in the Chamonix valley and geomorphology promoting their dispersion seem to explain such differences. Despite reaching lower atmospheric concentrations, NPAHs seemed to account up to 20% of carcinogenic potency of particulates collected at the sites away from pollution sources. The formation of secondary compounds such as NPAHs increases significantly the carcinogenic risk at the sites away from pollution sources. Study with 2-nitrofluoranthene/1-nitropyrene ratio showed that NPAH gas phase formation was hindered in winter, and when relative contribution from primary sources was higher. Nevertheless, in winter under specific conditions, evidence of secondary NPAH formations was observed at sub-urban and traffic sites (snowfalls) and rural site (accumulation of pollutants and snowfalls). For all sampling sites, the daytime OH initiated reaction seemed to be the dominant gas phase formation pathway over the NO 3 initiated reaction. The fraction of PAHs, OPAHs and NPAHs associated with the particle phase was strongly depending on their vapour pressure and the ambient conditions.

  17. Air oxygenation chemistry of 4-TBC catalyzed by chloro bridged dinuclear copper(II) complexes of pyrazole based tridentate ligands: synthesis, structure, magnetic and computational studies.

    PubMed

    Banerjee, Ishita; Samanta, Pabitra Narayan; Das, Kalyan Kumar; Ababei, Rodica; Kalisz, Marguerite; Girard, Adrien; Mathonière, Corine; Nethaji, M; Clérac, Rodolphe; Ali, Mahammad

    2013-02-01

    Four dinuclear bis(μ-Cl) bridged copper(II) complexes, [Cu(2)(μ-Cl)(2)(L(X))(2)](ClO(4))(2) (L(X) = N,N-bis[(3,5-dimethylpyrazole-1-yl)-methyl]benzylamine with X = H(1), OMe(2), Me(3) and Cl(4)), have been synthesized and characterized by the single crystal X-ray diffraction method. In these complexes, each copper(II) center is penta-coordinated with square-pyramidal geometry. In addition to the tridentate L(X) ligand, a chloride ion occupies the last position of the square plane. This chloride ion is also bonded to the neighboring Cu(II) site in its axial position forming an SP-I dinuclear Cu(II) unit that exhibits small intramolecular ferromagnetic interactions and supported by DFT calculations. The complexes 1-3 exhibit methylmonooxygenase (pMMO) behaviour and oxidise 4-tert-butylcatechol (4-TBCH(2)) with molecular oxygen in MeOH or MeCN to 4-tert-butyl-benzoquinone (4-TBQ), 5-methoxy-4-tert-butyl-benzoquinone (5-MeO-4-TBQ) as the major products along with 6,6'-Bu(t)-biphenyl-3,4,3',4'-tetraol and others as minor products. These are further confirmed by ESI- and FAB-mass analyses. A tentative catalytic cycle has been framed based on the mass spectral analysis of the products and DFT calculations on individual intermediates that are energetically feasible. PMID:23172025

  18. Systemic air embolism causing acute stroke and myocardial infarction after percutaneous transthoracic lung biopsy - a case report.

    PubMed

    Rehwald, Rafael; Loizides, Alexander; Wiedermann, Franz J; Grams, Astrid E; Djurdjevic, Tanja; Glodny, Bernhard

    2016-01-01

    The air embolism in this case was likely to have been caused by positioning the patient in a prone position, which was associated with the lesion to be biopsied being at a maximum height over the left atrium. Due to the resulting negative pressure, air entered through a fistula that formed between the airspace and the pulmonary vein. The air could have been trapped in the left atrium by positioning the patient in left lateral position. The event itself could have been prevented by positioning the patient in an ipsilateral dependent position during the biopsy. In addition to hyperbaric oxygen therapy, the preferred treatment options are positioning maneuvers, administration of pure oxygen, and heparinization. PMID:27154545

  19. Nitrogen transfers and air-sea N2O fluxes in the upwelling off Namibia within the oxygen minimum zone: a 3-D model approach

    NASA Astrophysics Data System (ADS)

    Gutknecht, E.; Dadou, I.; Le Vu, B.; Cambon, G.; Sudre, J.; Garçon, V.; Machu, E.; Rixen, T.; Kock, A.; Flohr, A.; Paulmier, A.; Lavik, G.

    2011-04-01

    As regions of high primary production and being often associated to Oxygen Minimum Zones (OMZs), Eastern Boundary Upwelling Systems (EBUS) represent key regions for the oceanic nitrogen (N) cycle. Indeed, by exporting the Organic Matter (OM) and nutrients produced in the coastal region to the open ocean, EBUS can play an important role in sustaining primary production in subtropical gyres. Losses of fixed inorganic N, through denitrification and anammox processes and through nitrous oxide (N2O) emissions to the atmosphere, take place in oxygen depleted environments such as EBUS, and alleviate the role of these regions as a source of N. In the present study, we developed a 3-D coupled physical/biogeochemical (ROMS/BioBUS) model for investigating the full N budget in the Namibian sub-system of the Benguela Upwelling System (BUS). The different state variables of a climatological experiment have been compared to different data sets (satellite and in situ observations) and show that the model is able to represent this biogeochemical oceanic region. The N transfer is investigated in the Namibian upwelling system using this coupled model, especially in the Walvis Bay area between 22° S and 24° S where the OMZ is well developed (O2 < 0.5 ml O2 l-1). The upwelling process advects 24.2 × 1010 mol N yr-1 of nitrate enriched waters over the first 100 m over the slope and over the continental shelf. The meridional advection by the alongshore Benguela current brings also nutrient-rich waters with 21.1 × 1010 mol N yr-1. 10.5 × 1010 mol N yr-1 of OM are exported outside of the continental shelf (between 0 and 100-m depth). 32.4% and 18.1% of this OM are exported by advection in the form of Dissolved and Particulate Organic Matters (DOM and POM), respectively, however vertical sinking of POM represents the main contributor (49.5%) to OM export outside of the first 100-m depth of the water column on the continental shelf. The continental slope also represents a net N export

  20. Oxygen concentration inside a functioning photosynthetic cell.

    PubMed

    Kihara, Shigeharu; Hartzler, Daniel A; Savikhin, Sergei

    2014-05-01

    The excess oxygen concentration in the photosynthetic membranes of functioning oxygenic photosynthetic cells was estimated using classical diffusion theory combined with experimental data on oxygen production rates of cyanobacterial cells. The excess oxygen concentration within the plesiomorphic cyanobacterium Gloeobactor violaceus is only 0.025 μM, or four orders of magnitude lower than the oxygen concentration in air-saturated water. Such a low concentration suggests that the first oxygenic photosynthetic bacteria in solitary form could have evolved ∼2.8 billion years ago without special mechanisms to protect them against reactive oxygen species. These mechanisms instead could have been developed during the following ∼500 million years while the oxygen level in the Earth's atmosphere was slowly rising. Excess oxygen concentrations within individual cells of the apomorphic cyanobacteria Synechocystis and Synechococcus are 0.064 and 0.25 μM, respectively. These numbers suggest that intramembrane and intracellular proteins in isolated oxygenic photosynthetic cells are not subjected to excessively high oxygen levels. The situation is different for closely packed colonies of photosynthetic cells. Calculations show that the excess concentration within colonies that are ∼40 μm or larger in diameter can be comparable to the oxygen concentration in air-saturated water, suggesting that species forming colonies require protection against reactive oxygen species even in the absence of oxygen in the surrounding atmosphere. PMID:24806920

  1. Surface oxidability of pure liquid metals and alloys

    NASA Astrophysics Data System (ADS)

    Arato, E.; Bernardi, M.; Giuranno, D.; Ricci, E.

    2012-01-01

    The analysis of the oxygen-liquid metal interaction is a topic of particular technological interest. A deep knowledge of the kinetics and transport mechanisms involved in the oxidation phenomena is necessary: the effect of oxidation reactions taking place in the gas phase and the evaporation of oxides must be considered. This paper aims to review our works in order to provide a systematic analysis of the oxidation of pure metals and determine the most likely to keeping oxygen-free the surface in a binary alloy. In addition, the upgrading of this theoretical approach, here briefly described, is addressed to give a contribution to a better understanding of the evolution of oxidation phenomena close to the solid-liquid-gas interfaces.

  2. Selective TNF-α targeting with infliximab attenuates impaired oxygen metabolism and contractile function induced by an acute exposure to air particulate matter.

    PubMed

    Marchini, Timoteo; D'Annunzio, Verónica; Paz, Mariela L; Cáceres, Lourdes; Garcés, Mariana; Perez, Virginia; Tasat, Deborah; Vanasco, Virginia; Magnani, Natalia; Gonzalez Maglio, Daniel; Gelpi, Ricardo J; Alvarez, Silvia; Evelson, Pablo

    2015-11-15

    Inflammation plays a central role in the onset and progression of cardiovascular diseases associated with the exposure to air pollution particulate matter (PM). The aim of this work was to analyze the cardioprotective effect of selective TNF-α targeting with a blocking anti-TNF-α antibody (infliximab) in an in vivo mice model of acute exposure to residual oil fly ash (ROFA). Female Swiss mice received an intraperitoneal injection of infliximab (10 mg/kg body wt) or saline solution, and were intranasally instilled with a ROFA suspension (1 mg/kg body wt). Control animals were instilled with saline solution and handled in parallel. After 3 h, heart O2 consumption was assessed by high-resolution respirometry in left ventricle tissue cubes and isolated mitochondria, and ventricular contractile reserve and lusitropic reserve were evaluated according to the Langendorff technique. ROFA instillation induced a significant decrease in tissue O2 consumption and active mitochondrial respiration by 32 and 31%, respectively, compared with the control group. While ventricular contractile state and isovolumic relaxation were not altered in ROFA-exposed mice, impaired contractile reserve and lusitropic reserve were observed in this group. Infliximab pretreatment significantly attenuated the decrease in heart O2 consumption and prevented the decrease in ventricular contractile and lusitropic reserve in ROFA-exposed mice. Moreover, infliximab-pretreated ROFA-exposed mice showed conserved left ventricular developed pressure and cardiac O2 consumption in response to a β-adrenergic stimulus with isoproterenol. These results provides direct evidence linking systemic inflammation and altered cardiac function following an acute exposure to PM and contribute to the understanding of PM-associated cardiovascular morbidity and mortality. PMID:26386109

  3. The role of oxygen in the photostimulation luminescence process of europium doped potassium chloride

    PubMed Central

    Xiao, Zhiyan; Mazur, Thomas R.; Driewer, Joseph P.; Li, H. Harold

    2015-01-01

    A recent suggestion that europium doped potassium chloride (KCl:Eu2+) has the potential to significantly advance the state-of-the-art in radiation therapy dosimetry has generated a renewed interest in a classic storage phosphor material. The purposes of this work are to investigate the role of oxygen in the photostimulation luminescence (PSL) process and to determine if both increased PSL yield and improved temporal stability could be realized in KCl:Eu2+ by incorporating oxygen in the material fabrication process. Regardless of synthesis atmosphere, air or pure nitrogen, PSL amplitude shows a maximum at 1.0 mol % Eu. Depending on europium concentration, dosimeters fabricated in air exhibit stronger PSL by a factor of 2 to 4 compared to those made in N2. There is no change in PSL stimulation spectrum while noticeable shifts in both photoluminescence and PSL emission spectra are observed for air versus nitrogen. Almost all charge-storage centers are spatially correlated, suggesting oxygen’s stabilization role in the PSL process. However, oxygen alone does not improve material’s temporal stability in the first few hours post irradiation at room temperature, probably because a significant portion of radiation-induced holes are stored in the Vk centers which are mobile. PMID:25897274

  4. Pure and Pseudo-pure Fluid Thermophysical Property Evaluation and the Open-Source Thermophysical Property Library CoolProp

    PubMed Central

    2014-01-01

    Over the last few decades, researchers have developed a number of empirical and theoretical models for the correlation and prediction of the thermophysical properties of pure fluids and mixtures treated as pseudo-pure fluids. In this paper, a survey of all the state-of-the-art formulations of thermophysical properties is presented. The most-accurate thermodynamic properties are obtained from multiparameter Helmholtz-energy-explicit-type formulations. For the transport properties, a wider range of methods has been employed, including the extended corresponding states method. All of the thermophysical property correlations described here have been implemented into CoolProp, an open-source thermophysical property library. This library is written in C++, with wrappers available for the majority of programming languages and platforms of technical interest. As of publication, 110 pure and pseudo-pure fluids are included in the library, as well as properties of 40 incompressible fluids and humid air. The source code for the CoolProp library is included as an electronic annex. PMID:24623957

  5. Subtask 3.12 - Oxygen-Fired CFBC

    SciTech Connect

    Douglas Hajicek; Mark Musich; Ann Henderson

    2007-02-28

    Traditionally, air is used as the source of oxygen for firing a combustion system. A fully oxygen-fired circulating fluidized-bed combustion (CFBC) system would result in the production of a flue gas stream consisting of mostly carbon dioxide and water. The concentrated carbon dioxide stream would be available for sequestering or other purposes. Temperatures in an oxygen-blown CFBC system would be controlled by a combination of flue gas recycle, solids recirculation, and by appropriately sizing and locating the amount of heat-transfer surface required. Flue gas recycle provides the additional gas required for adequate fluidization and circulation of solids replacing the nitrogen that would be present in an air-blown system. The amount of flue gas recycle will determine how much of the remaining heat from the coal combustion will have to be removed. If the amount of flue gas recycle required by increasing solids recirculation and oxygen staging is limited, introducing the pure oxygen at multiple locations in the combustor to result in a more even temperature profile should result in a more compact system, thus reducing initial capital costs for construction. The overall efficiency of the process should be greater than that of an air-blown system since less fuel is required for the creation of the same amount of energy. The Energy & Environmental Research Center (EERC) is in a unique position to advance this technology. It has a world-class CFBC pilot plant, has experience with firing a wide range of fuels in our air-fired CFBC pilot plant, has prior experience with oxygen-firing a slagging furnace system in a pulverized coal-fired mode with a bituminous coal, and has all of the components required for oxygen-firing right next to the CFBC pilot plant already in place. An engineering study was performed to identify methods, an overall appropriate configuration, and an operating strategy for a fully oxygen-fired CFBC pilot plant by: (1) developing a plan to optimize

  6. Oxygen toxicity during artificial ventilation

    PubMed Central

    Brewis, R. A. L.

    1969-01-01

    Repeated pulmonary collapse and changes suggestive of a severe alveolar-capillary diffusion defect were observed over a period of 20 days in a patient who was receiving artificial ventilation because of status epilepticus. Profound cyanosis followed attempts to discontinue assisted ventilation. The Bird Mark 8 respirator employed was found to be delivering approximately 90% oxygen on the air-mix setting and pulmonary oxygen toxicity was suspected. Radiological improvement and progressive resolution of the alveolar-capillary block followed gradual reduction of the inspired concentration over nine days. The management and prevention of this complication are discussed. The inspired oxygen concentration should be routinely monitored in patients receiving intermittent positive pressure ventilation, and the concentration should not be higher than that required to maintain adequate oxygenation. The Bird Mark 8 respirator has an inherent tendency to develop high oxygen concentrations on the air-mix setting, and the machine should therefore be driven from a compressed air source unless high concentrations of oxygen are essential. Images PMID:4900444

  7. Technology advancement of an oxygen generation subsystem

    NASA Technical Reports Server (NTRS)

    Lee, M. K.; Burke, K. A.; Schubert, F. H.; Wynveen, R. A.

    1979-01-01

    An oxygen generation subsystem based on water electrolysis was developed and tested to further advance the concept and technology of the spacecraft air revitalization system. Emphasis was placed on demonstrating the subsystem integration concept and hardware maturity at a subsystem level. The integration concept of the air revitalization system was found to be feasible. Hardware and technology of the oxygen generation subsystem was demonstrated to be close to the preprototype level. Continued development of the oxygen generation technology is recommended to further reduce the total weight penalties of the oxygen generation subsystem through optimization.

  8. Gas transfer velocities for quantifying methane, oxygen and other gas fluxes through the air-water interface of wetlands with emergent vegetation

    NASA Astrophysics Data System (ADS)

    Poindexter, C.; Variano, E. A.

    2012-12-01

    Empirical models for the gas transfer velocity, k, in the ocean, lakes and rivers are fairly well established, but there are few data to predict k for wetlands. We have conducted experiments in a simulated emergent marsh in the laboratory to explore the relationship between k, wind shear and thermal convection. Now we identify the implications of these results for gas transfer in actual wetlands by (1) quantifying the range of wind conditions in emergent vegetation canopies and the range of thermal convection intensities in wetland water columns, and (2) describing the non-linear interaction of these two stirring forces over their relevant ranges in wetlands. We measured mean wind speeds and wind speed variance within the shearless region of a Schoenoplectus-Typha marsh canopy in the Sacramento-San Joaquin Delta (Northern California, USA). The mean wind speed within this region, , is significantly smaller than wind above the canopy. Based on our laboratory experiments, for calm or even average wind conditions in this emergent marsh k600 is only on the order 0.1 cm hr-1 (for neutrally or stably stratified water columns). We parameterize unstable thermal stratification and the resulting thermal convection using the heat flux through the air-water interface, q. We analyzed a water temperature record for the Schoenoplectus-Typha marsh to obtain a long-term heat flux record. We used these heat flux data along with short-term heat flux data from other wetlands in the literature to identify the range of the gas transfer velocity associated with thermal convection in wetlands. The typical range of heat fluxes through water columns shaded by closed emergent canopies (-200 W m-2 to +200 W m-2) yields k600 values of 0.5 - 2.5 cm hr-1 according to the model we developed in the laboratory. Thus for calm or average wind conditions, the gas transfer velocity associated with thermal convection is significantly larger than the gas transfer velocity associated with wind

  9. Cathodic oxygen reduction catalyzed by bacteria in microbial fuel cells.

    PubMed

    Rabaey, Korneel; Read, Suzanne T; Clauwaert, Peter; Freguia, Stefano; Bond, Philip L; Blackall, Linda L; Keller, Jurg

    2008-05-01

    Microbial fuel cells (MFCs) have the potential to combine wastewater treatment efficiency with energetic efficiency. One of the major impediments to MFC implementation is the operation of the cathode compartment, as it employs environmentally unfriendly catalysts such as platinum. As recently shown, bacteria can facilitate sustainable and cost-effective cathode catalysis for nitrate and also oxygen. Here we describe a carbon cathode open to the air, on which attached bacteria catalyzed oxygen reduction. The bacteria present were able to reduce oxygen as the ultimate electron acceptor using electrons provided by the solid-phase cathode. Current densities of up to 2.2 A m(-2) cathode projected surface were obtained (0.303+/-0.017 W m(-2), 15 W m(-3) total reactor volume). The cathodic microbial community was dominated by Sphingobacterium, Acinetobacter and Acidovorax sp., according to 16S rRNA gene clone library analysis. Isolates of Sphingobacterium sp. and Acinetobacter sp. were obtained using H(2)/O(2) mixtures. Some of the pure culture isolates obtained from the cathode showed an increase in the power output of up to three-fold compared to a non-inoculated control, that is, from 0.015+/-0.001 to 0.049+/-0.025 W m(-2) cathode projected surface. The strong decrease in activation losses indicates that bacteria function as true catalysts for oxygen reduction. Owing to the high overpotential for non-catalyzed reduction, oxygen is only to a limited extent competitive toward the electron donor, that is, the cathode. Further research to refine the operational parameters and increase the current density by modifying the electrode surface and elucidating the bacterial metabolism is warranted. PMID:18288216

  10. Eight sages over five centuries share oxygen's discovery.

    PubMed

    Severinghaus, John W

    2016-09-01

    During the last century, historians have discovered that between the 13th and 18th centuries, at least six sages discovered that the air we breathe contains something that we need and use. Ibn al-Nafis (1213-1288) in Cairo and Michael Servetus (1511-1553) in France accurately described the pulmonary circulation and its effect on blood color. Michael Sendivogius (1566-1636) in Poland called a part of air "the food of life" and identified it as the gas made by heating saltpetre. John Mayow (1641-1679) in Oxford found that one-fifth of air was a special gas he called "spiritus nitro aereus." Carl Wilhelm Scheele (1742-1786) in Uppsala generated a gas he named "fire air" by heating several metal calcs. He asked Lavoisier how it fit the phlogiston theory. Lavoisier never answered. In 1744, Joseph Priestley (1733-1804) in England discovered how to make part of air by heating red calc of mercury. He found it brightened a flame and supported life in a mouse in a sealed bottle. He called it "dephlogisticated air." He published and personally told Lavoisier and other chemists about it. Lavoisier never thanked him. After 9 years of generating and studying its chemistry, he couldn't understand whether it was a new element. He still named it "principe oxigene." He was still not able to disprove phlogiston. Henry Cavendish (1731-1810) made an inflammable gas in 1766. He and Priestley noted that its flame made a dew. Cavendish proved the dew was pure water and published this in 1778, but all scientists called it impossible to make water, an element. In 1783, on June 24th, Lavoisier was urged to try it, and, when water appeared, he realized that water was not an element but a compound of two gases, proving that oxygen was an element. He then demolished phlogiston and began the new chemistry revolution. PMID:27458241

  11. The prospects for polarized target materials with pure carbon background

    SciTech Connect

    Hill, D.A.

    1992-10-06

    None of the materials presently in common use for polarized proton targets has a pure carbon nuclear background. The alcohols and diols contain some oxygen, and the ammonia and amine-based materials contain nitrogen and/or other noncarbon species. In the latter cases the noncarbon nuclei are measurably polarized as a concomitant of the process used to polarize the hydrogen nuclei. The relative simplicity of a pure carbon background would be advantageous for most types of scattering experiments and perhaps crucial for some. In addition to simplifying the kinematics of background events, pure carbon is relatively easy to prepare as a ``dummy`` target for background subtraction. Also, in such a target material, {sup 13}C-enrichment would yield a clean polarized {sup 13}C material. In this note I explore the possibilities for such materials, touching upon only what I consider to be the ``high`` points. The subject matter is capable of nearly endless ramification and speculation. In fact, owing to a general lack of relevant experimental data, even this relatively brief note contains much that is speculative to some degree.

  12. The prospects for polarized target materials with pure carbon background

    SciTech Connect

    Hill, D.A.

    1992-10-06

    None of the materials presently in common use for polarized proton targets has a pure carbon nuclear background. The alcohols and diols contain some oxygen, and the ammonia and amine-based materials contain nitrogen and/or other noncarbon species. In the latter cases the noncarbon nuclei are measurably polarized as a concomitant of the process used to polarize the hydrogen nuclei. The relative simplicity of a pure carbon background would be advantageous for most types of scattering experiments and perhaps crucial for some. In addition to simplifying the kinematics of background events, pure carbon is relatively easy to prepare as a dummy'' target for background subtraction. Also, in such a target material, [sup 13]C-enrichment would yield a clean polarized [sup 13]C material. In this note I explore the possibilities for such materials, touching upon only what I consider to be the high'' points. The subject matter is capable of nearly endless ramification and speculation. In fact, owing to a general lack of relevant experimental data, even this relatively brief note contains much that is speculative to some degree.

  13. Method of preparing pure fluorine gas

    DOEpatents

    Asprey, Larned B.

    1976-01-01

    A simple, inexpensive system for purifying and storing pure fluorine is described. The method utilizes alkali metal-nickel fluorides to absorb tank fluorine by forming nickel complex salts and leaving the gaseous impurities which are pumped away. The complex nickel fluoride is then heated to evolve back pure gaseous fluorine.

  14. Retinal oxygen extraction in humans

    NASA Astrophysics Data System (ADS)

    Werkmeister, René M.; Schmidl, Doreen; Aschinger, Gerold; Doblhoff-Dier, Veronika; Palkovits, Stefan; Wirth, Magdalena; Garhöfer, Gerhard; Linsenmeier, Robert A.; Leitgeb, Rainer A.; Schmetterer, Leopold

    2015-10-01

    Adequate function of the retina is dependent on proper oxygen supply. In humans, the inner retina is oxygenated via the retinal circulation. We present a method to calculate total retinal oxygen extraction based on measurement of total retinal blood flow using dual-beam bidirectional Doppler optical coherence tomography and measurement of oxygen saturation by spectrophotometry. These measurements were done on 8 healthy subjects while breathing ambient room air and 100% oxygen. Total retinal blood flow was 44.3 ± 9.0 μl/min during baseline and decreased to 18.7 ± 4.2 μl/min during 100% oxygen breathing (P < 0.001) resulting in a pronounced decrease in retinal oxygen extraction from 2.33 ± 0.51 μl(O2)/min to 0.88 ± 0.14 μl(O2)/min during breathing of 100% oxygen. The method presented in this paper may have significant potential to study oxygen metabolism in hypoxic retinal diseases such as diabetic retinopathy.

  15. Retinal oxygen extraction in humans.

    PubMed

    Werkmeister, René M; Schmidl, Doreen; Aschinger, Gerold; Doblhoff-Dier, Veronika; Palkovits, Stefan; Wirth, Magdalena; Garhöfer, Gerhard; Linsenmeier, Robert A; Leitgeb, Rainer A; Schmetterer, Leopold

    2015-01-01

    Adequate function of the retina is dependent on proper oxygen supply. In humans, the inner retina is oxygenated via the retinal circulation. We present a method to calculate total retinal oxygen extraction based on measurement of total retinal blood flow using dual-beam bidirectional Doppler optical coherence tomography and measurement of oxygen saturation by spectrophotometry. These measurements were done on 8 healthy subjects while breathing ambient room air and 100% oxygen. Total retinal blood flow was 44.3 ± 9.0 μl/min during baseline and decreased to 18.7 ± 4.2 μl/min during 100% oxygen breathing (P < 0.001) resulting in a pronounced decrease in retinal oxygen extraction from 2.33 ± 0.51 μl(O2)/min to 0.88 ± 0.14 μl(O2)/min during breathing of 100% oxygen. The method presented in this paper may have significant potential to study oxygen metabolism in hypoxic retinal diseases such as diabetic retinopathy. PMID:26503332

  16. Retinal oxygen extraction in humans

    PubMed Central

    Werkmeister, René M.; Schmidl, Doreen; Aschinger, Gerold; Doblhoff-Dier, Veronika; Palkovits, Stefan; Wirth, Magdalena; Garhöfer, Gerhard; Linsenmeier, Robert A.; Leitgeb, Rainer A.; Schmetterer, Leopold

    2015-01-01

    Adequate function of the retina is dependent on proper oxygen supply. In humans, the inner retina is oxygenated via the retinal circulation. We present a method to calculate total retinal oxygen extraction based on measurement of total retinal blood flow using dual-beam bidirectional Doppler optical coherence tomography and measurement of oxygen saturation by spectrophotometry. These measurements were done on 8 healthy subjects while breathing ambient room air and 100% oxygen. Total retinal blood flow was 44.3 ± 9.0 μl/min during baseline and decreased to 18.7 ± 4.2 μl/min during 100% oxygen breathing (P < 0.001) resulting in a pronounced decrease in retinal oxygen extraction from 2.33 ± 0.51 μl(O2)/min to 0.88 ± 0.14 μl(O2)/min during breathing of 100% oxygen. The method presented in this paper may have significant potential to study oxygen metabolism in hypoxic retinal diseases such as diabetic retinopathy. PMID:26503332

  17. Oxygen Systems Cleaners for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Davis, Samuel E.; Lowery, Freida

    1997-01-01

    New environmental regulations have forced extensive evaluations of many different cleaning agents for use in oxygen systems. This is no simple process because pure oxygen is a very strong oxidizer, and when placed in contact with a foreign substance, the combination may be explosive. This foreign substance can easily be a cleaning agent residue left over in the oxygen system after cleaning. This paper focuses on the factors that must be considered when selecting a cleaning agent for oxygen systems, as well as the approval processes which are currently being utilized by NASA for oxygen compatibility of materials. This paper will provide a working description of how to begin selecting a cleaning agent for oxygen systems. The paper will present the following: Background information on the necessity of a stringent selection process for oxygen system cleaners; Specifications and regulations concerning cleaning for oxygen service; Changing oxygen cleaning specifications given current environmental concerns; Testing for cleanliness in oxygen systems, Cleaning agents that have been tested for oxygen systems, including an extensive list of some of the newer 'environmentally friendly' cleaning agents; and Test results and conclusions from the testing. The paper will also provide instructions on the proper procedures for obtaining NASA approval on a candidate oxygen systems cleaning agent.

  18. Long-term carbide development in high-velocity oxygen fuel/high-velocity air fuel Cr3C2-NiCr coatings heat treated at 900 °C

    NASA Astrophysics Data System (ADS)

    Matthews, S.; Hyland, M.; James, B.

    2004-12-01

    During the deposition of Cr3C2-NiCr coatings, compositional degradation occurs, primarily through the dissolution of the carbide phase into the matrix. Exposure at an elevated temperature leads to transformations in the compositional distribution and microstructure. While these have been investigated in short-term trials, no systematic investigations of the long-term microstructural development have been presented for high-velocity sprayed coatings. In this work, high-velocity air fuel (HVAF) and high-velocity oxygen fuel (HVOF) coatings were treated at 900 °C for up to 60 days. Rapid refinement of the supersaturated matrix phase occurred, with the degree of matrix phase alloying continuing to decrease over the following 20 to 40 days. Carbide nucleation in the HVAF coatings occurred preferentially on the retained carbide grains, while that in the HVOF coatings developed in the regions of greatest carbide dissolution. This difference resulted in a variation in carbide morphologies. Preferential horizontal growth was evident in both coatings over the first 20 to 30 days of exposure, beyond which spheroidization of the microstructure occurred. After 30 days, the carbide morphology of both coatings was comparable, tending toward an expansive structure of coalesced carbide grains. The development of the carbide phase played a significant role in the microhardness variation of these coatings with time.

  19. Sample Acquisition and Analytical Chemistry Challenges to Verifying Compliance to Aviators Breathing Oxygen (ABO) Purity Specification

    NASA Technical Reports Server (NTRS)

    Graf, John

    2015-01-01

    NASA has been developing and testing two different types of oxygen separation systems. One type of oxygen separation system uses pressure swing technology, the other type uses a solid electrolyte electrochemical oxygen separation cell. Both development systems have been subjected to long term testing, and performance testing under a variety of environmental and operational conditions. Testing these two systems revealed that measuring the product purity of oxygen, and determining if an oxygen separation device meets Aviator's Breathing Oxygen (ABO) specifications is a subtle and sometimes difficult analytical chemistry job. Verifying product purity of cryogenically produced oxygen presents a different set of analytical chemistry challenges. This presentation will describe some of the sample acquisition and analytical chemistry challenges presented by verifying oxygen produced by an oxygen separator - and verifying oxygen produced by cryogenic separation processes. The primary contaminant that causes gas samples to fail to meet ABO requirements is water. The maximum amount of water vapor allowed is 7 ppmv. The principal challenge of verifying oxygen produced by an oxygen separator is that it is produced relatively slowly, and at comparatively low temperatures. A short term failure that occurs for just a few minutes in the course of a 1 week run could cause an entire tank to be rejected. Continuous monitoring of oxygen purity and water vapor could identify problems as soon as they occur. Long term oxygen separator tests were instrumented with an oxygen analyzer and with an hygrometer: a GE Moisture Monitor Series 35. This hygrometer uses an aluminum oxide sensor. The user's manual does not report this, but long term exposure to pure oxygen causes the aluminum oxide sensor head to bias dry. Oxygen product that exceeded the 7 ppm specification was improperly accepted, because the sensor had biased. The bias is permanent - exposure to air does not cause the sensor to

  20. Conformal pure radiation with parallel rays

    NASA Astrophysics Data System (ADS)

    Leistner, Thomas; Nurowski, Paweł

    2012-03-01

    We define pure radiation metrics with parallel rays to be n-dimensional pseudo-Riemannian metrics that admit a parallel null line bundle K and whose Ricci tensor vanishes on vectors that are orthogonal to K. We give necessary conditions in terms of the Weyl, Cotton and Bach tensors for a pseudo-Riemannian metric to be conformal to a pure radiation metric with parallel rays. Then, we derive conditions in terms of the tractor calculus that are equivalent to the existence of a pure radiation metric with parallel rays in a conformal class. We also give analogous results for n-dimensional pseudo-Riemannian pp-waves.

  1. Using oxygen at home

    MedlinePlus

    ... DO NOT use oil-based products, such as petroleum jelly (Vaseline). Ask your oxygen equipment provider about ... oxygen; Hypoxia - home oxygen; Hospice - home oxygen References American Thoracic Society. Why do I need oxygen therapy? ...

  2. Laser-induced generation of pure tensile stresses

    SciTech Connect

    Niemz, M.H.; Lin, C.P.; Pitsillides, C.; Cui, J.; Doukas, A.G.; Deutsch, T.F.

    1997-05-01

    While short compressive stresses can readily be produced by laser ablation, the generation of pure tensile stresses is more difficult. We demonstrate that a 90{degree} prism made of polyethylene can serve to produce short and pure tensile stresses. A compressive wave is generated by ablating a thin layer of strongly absorbing ink on one surface of the prism with a Q-switched frequency-doubled Nd:YAG laser. The compressive wave driven into the prism is reflected as a tensile wave by the polyethylene-air interface at its long surface. The low acoustic impedance of polyethylene makes it ideal for coupling tensile stresses into liquids. In water, tensile stresses up to {minus}200bars with a rise time of the order of 20 ns and a duration of 100 ns are achieved. The tensile strength of water is determined for pure tensile stresses lasting for 100 ns only. The technique has potential application in studying the initiation of cavitation in liquids and in comparing the effect of compressive and tensile stress transients on biological media. {copyright} {ital 1997 American Institute of Physics.}

  3. Intraphagosomal oxygen in stimulated macrophages.

    PubMed

    James, P E; Grinberg, O Y; Michaels, G; Swartz, H M

    1995-05-01

    A new electron paramagnetic resonance (EPR)-based method was developed to obtain selective information on pO2 in a specific intracellular compartment (phagosomes). This method did not require the use of a broadening agent thereby eliminating one of the potential sources of experimental error with EPR oximetry. An oxygen-sensitive probe (4-(Trimethylammonium) 2,2,6,6-tetramethylpiperidine-d17-1-oxyl iodide (d-Cat1)) which has a net positive charge, was incorporated selectively into the phagosomes of macrophages stimulated with zymosan. Extracellular oxygen was measured by addition of a neutral nitroxide (4-oxo-2,2,6,6-tetramethylpiperidine-d16-1-oxyl (15N PDT)) to this same sample. Measurements based on EPR linewidths showed the average intraphagosomal oxygen concentration to be 11.2 +/- 3.4 microM lower than that measured from the extracellular compartment when the sample was perfused with air, and this was increased on stimulation of mitochondrial consumption or by increasing the oxygen concentration in the extracellular compartment. These experiments provide what we believe to be the first reported measurements of the oxygen concentration in a specific intracellular location (intraphagosomal) and its comparison with the oxygen concentration in the extracellular space. The observed gradient cannot be explained in terms of known coefficients of diffusion, and these results are consistent with previous reports that a gradient in oxygen concentration can occur between the average intracellular and extracellular concentration of oxygen. PMID:7706368

  4. 14. DETAIL SHOWING HYDROGEN (LEFT) AND OXYGEN (RIGHT) PREVALVES. Looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. DETAIL SHOWING HYDROGEN (LEFT) AND OXYGEN (RIGHT) PREVALVES. Looking southeast. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  5. 16. DETAIL SHOWING LIQUID OXYGEN TANK FOURTEENINCH BALL VALVE. Looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. DETAIL SHOWING LIQUID OXYGEN TANK FOURTEEN-INCH BALL VALVE. Looking southwest. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  6. 17. DETAIL, FOURTEENINCH LIQUID OXYGEN BALL VALVE. Looking south southeast. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. DETAIL, FOURTEEN-INCH LIQUID OXYGEN BALL VALVE. Looking south southeast. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  7. Test Would Quantify Combustion Oxygen From Different Sources

    NASA Technical Reports Server (NTRS)

    Tapphorn, Ralph M.

    1993-01-01

    Proposed isotope-enrichment scheme enables determination of contributions of dual sources of oxygen for combustion. Liquid oxygen or other artificial stream enriched with O(18) to about 1 percent by weight. Combustion products analyzed by mass spectrometer to measure relative abundances of H2O(18) and H2O(16). From relative abundances of water products measured, one computes relative contribution of oxygen extracted from stream compared to other source of oxygen in combustion process. Used to determine contributions of natural oxygen in air and liquid oxygen supplied in separate stream mixed with air or sent directly into combustion chamber.

  8. Mussel-inspired one-pot synthesis of transition metal and nitrogen co-doped carbon (M/N-C) as efficient oxygen catalysts for Zn-air batteries.

    PubMed

    Li, Bing; Chen, Ye; Ge, Xiaoming; Chai, Jianwei; Zhang, Xiao; Hor, T S Andy; Du, Guojun; Liu, Zhaolin; Zhang, Hua; Zong, Yun

    2016-03-01

    Transition metal and nitrogen co-doping into carbon is an effective approach to promote the catalytic activities towards the oxygen reduction reaction (ORR) and/or oxygen evolution reaction (OER) in the resultant electrocatalysts, M/N-C. The preparation of such catalysts, however, is often complicated and in low yield. Herein we report a robust approach for easy synthesis of M/N-C hybrids in high yield, which includes a mussel-inspired polymerization reaction at room temperature and a subsequent carbonization process. With the introduction of selected transition metal salts into an aqueous solution of dopamine (DA), the obtained mixture self-polymerizes to form metal-containing polydopamine (M-PDA) composites, e.g. Co-PDA, Ni-PDA and Fe-PDA. Upon carbonization at elevated temperatures, these metal-containing composites were converted into M/N-C, i.e. Co-PDA-C, Ni-PDA-C and Fe-PDA-C, respectively, whose morphologies, chemical compositions, and electrochemical performances were fully studied. Enhanced ORR activities were found in all the obtained hybrids, with Co-PDA-C standing out as the most promising catalyst with excellent stability and catalytic activities towards both ORR and OER. This was further proven in Zn-air batteries (ZnABs) in terms of discharge voltage stability and cycling performance. At a discharge-charge current density of 2 mA cm(-2) and 1 h per cycle, the Co-PDA-C based ZnABs were able to steadily cycle up to 500 cycles with only a small increase in the discharge-charge voltage gap which notably outperformed Pt/C; at a discharge current density of 5 mA cm(-2), the battery continuously discharged for more than 540 h with the discharge voltage above 1 V and a voltage drop rate of merely 0.37 mV h(-1). With the simplicity and scalability of the synthetic approach and remarkable battery performances, the Co-PDA-C hybrid catalyst is anticipated to play an important role in practical ZnABs. PMID:26864616

  9. Making Pure Fine-Grained Inorganic Powder

    NASA Technical Reports Server (NTRS)

    Wood, C.

    1985-01-01

    Sustained arc plasma chemical reactor fabricates very-fine-grained inorganic solids having low thermal conductivity. Powder fabrication method, based on plasma tube technique produces pure solids without contamination commonly produced by grinding.

  10. [Biological properties of immunochemically pure tetanus antitoxin].

    PubMed

    Kornilova, A V; Khavkin, Iu A; Batalova, T A; Aleksevich, Ia I; Baschenko, I A

    1983-02-01

    Immunochemically pure tetanus antitoxin obtained from enzyme-treated horse serum is less reactogenic and anaphylactogenic and possesses higher therapeutic properties than antitoxin purified by nonspecific physico-chemical methods and containing ballast antigens. Due to its increased persistence in the recipient's body, the immunochemically pure antitoxin induces passive immunity in considerably lower doses than the preparations purified by the method "Diaferm-3". PMID:6340393

  11. Notes on the ambitwistor pure spinor string

    NASA Astrophysics Data System (ADS)

    Jusinskas, Renann Lipinski

    2016-05-01

    In this work, some aspects of the ambitwistor pure spinor string are investigated. The b ghost is presented and its main properties are derived in a simple way, very similar to the usual pure spinor b ghost construction. The heterotic case is also addressed with a new proposal for the BRST charge. The BRST cohomology is shown to correctly describe the heterotic supergravity spectrum and a semi-composite b ghost is constructed.

  12. Development of a model to determine oxygen consumption when crawling

    PubMed Central

    Pollard, J.P.; Heberger, J.R.; Dempsey, P.G.

    2016-01-01

    During a mine disaster or emergency, underground air can quickly become contaminated. In these circumstances, all underground mine workers are taught to don breathable air supply units at the first sign of an emergency. However, no contemporary oxygen consumption data is available for the purposes of designing breathing air supply equipment specifically for mine escape. Further, it would be useful to quantify the oxygen requirements of breathing air supply users for various escape scenarios. To address this need, 14 participants crawled a distance of 305 m each while their breath-by-breath oxygen consumption measurements were taken. Using these data, linear regression models were developed to determine peak and average oxygen consumption rates as well as total oxygen consumption. These models can be used by manufacturers of breathing air supply equipment to aid in the design of devices that would be capable of producing sufficient on-demand oxygen to allow miners to perform self-escape. PMID:26997858

  13. Rehabilitation of pure alexia: A review

    PubMed Central

    Starrfelt, Randi; Ólafsdóttir, Rannveig Rós; Arendt, Ida-Marie

    2013-01-01

    Acquired reading problems caused by brain injury (alexia) are common, either as a part of an aphasic syndrome, or as an isolated symptom. In pure alexia, reading is impaired while other language functions, including writing, are spared. Being in many ways a simple syndrome, one would think that pure alexia was an easy target for rehabilitation efforts. We review the literature on rehabilitation of pure alexia from 1990 to the present, and find that patients differ widely on several dimensions, such as alexia severity and associated deficits. Many patients reported to have pure alexia in the reviewed studies, have associated deficits such as agraphia or aphasia and thus do not strictly conform to the diagnosis. Few studies report clear and generalisable effects of training, none report control data, and in many cases the reported findings are not supported by statistics. We can, however, tentatively conclude that Multiple Oral Re-reading techniques may have some effect in mild pure alexia where diminished reading speed is the main problem, while Tacile-Kinesthetic training may improve letter identification in more severe cases of alexia. There is, however, still a great need for well-designed and controlled studies of rehabilitation of pure alexia. PMID:23808895

  14. Oxygen Transport Ceramic Membranes

    SciTech Connect

    S. Bandopadhyay; N. Nagabhushana; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

    2005-02-01

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. Thermogravimetric analysis (TGA) was carried out on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} to investigate oxygen deficiency ({delta}) of the sample. The TGA was performed in a controlled atmosphere using oxygen, argon, carbon monoxide and carbon dioxide with adjustable gas flow rates. In this experiment, the weight loss and gain of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} was directly measured by TGA. The weight change of the sample was evaluated at between 600 and 1250 C in air or 1000 C as a function of oxygen partial pressure. The oxygen deficiencies calculated from TGA data as a function of oxygen activity and temperature will be estimated and compared with that from neutron diffraction measurement in air. The LSFT and LSFT/CGO membranes were fabricated from the powder obtained from Praxair Specialty Ceramics. The sintered membranes were subjected to microstructure analysis and hardness analysis. The LSFT membrane is composed of fine grains with two kinds of grain morphology. The grain size distribution was characterized using image analysis. In LSFT/CGO membrane a lot of grain pullout was observed from the less dense, porous phase. The hardness of the LSFT and dual phase membranes were studied at various loads. The hardness values obtained from the cross section of the membranes were also compared to that of the values obtained from the surface. An electrochemical cell has been designed and built for measurements of the Seebeck coefficient as a function of temperature and pressure. Measurements on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} as a function of temperature an oxygen partial pressure are reported. Further analysis of the dilatometry data obtained previously is presented. A series of isotope transients

  15. Tipping point analysis of atmospheric oxygen concentration

    NASA Astrophysics Data System (ADS)

    Livina, Valerie N.; Vaz Martins, Teresa M.; Forbes, Alistair

    2015-04-01

    We apply tipping point analysis to atmospheric oxygen concentration records. We warn that decrease of oxygen concentration from 21% to 19% would lead to significant health problems for humans and other animals, and estimate the time scale of such decline under various antropogenic scenarios. We suggest that society should be careful with introduction of new mass technologies that utilise double sink of atmospheric oxygen by both combustion and air-consuming synthesis in energy generation and product manufacturing.

  16. Diffusion of oxygen (1); isoquinoline (2)

    NASA Astrophysics Data System (ADS)

    Winkelmann, J.

    This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Börnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) oxygen; (2) isoquinoline

  17. Sterilization by oxygen plasma

    NASA Astrophysics Data System (ADS)

    Moreira, Adir José; Mansano, Ronaldo Domingues; Andreoli Pinto, Terezinha de Jesus; Ruas, Ronaldo; Zambon, Luis da Silva; da Silva, Mônica Valero; Verdonck, Patrick Bernard

    2004-07-01

    The use of polymeric medical devices has stimulated the development of new sterilization methods. The traditional techniques rely on ethylene oxide, but there are many questions concerning the carcinogenic properties of the ethylene oxide residues adsorbed on the materials after processing. Another common technique is the gamma irradiation process, but it is costly, its safe operation requires an isolated site and it also affects the bulk properties of the polymers. The use of a gas plasma is an elegant alternative sterilization technique. The plasma promotes an efficient inactivation of the micro-organisms, minimises the damage to the materials and presents very little danger for personnel and the environment. Pure oxygen reactive ion etching type of plasmas were applied to inactivate a biologic indicator, the Bacillus stearothermophilus, to confirm the efficiency of this process. The sterilization processes took a short time, in a few minutes the mortality was complete. In situ analysis of the micro-organisms' inactivating time was possible using emission spectrophotometry. The increase in the intensity of the 777.5 nm oxygen line shows the end of the oxidation of the biologic materials. The results were also observed and corroborated by scanning electron microscopy.

  18. Mussel-inspired one-pot synthesis of transition metal and nitrogen co-doped carbon (M/N-C) as efficient oxygen catalysts for Zn-air batteries

    NASA Astrophysics Data System (ADS)

    Li, Bing; Chen, Ye; Ge, Xiaoming; Chai, Jianwei; Zhang, Xiao; Hor, T. S. Andy; Du, Guojun; Liu, Zhaolin; Zhang, Hua; Zong, Yun

    2016-02-01

    Transition metal and nitrogen co-doping into carbon is an effective approach to promote the catalytic activities towards the oxygen reduction reaction (ORR) and/or oxygen evolution reaction (OER) in the resultant electrocatalysts, M/N-C. The preparation of such catalysts, however, is often complicated and in low yield. Herein we report a robust approach for easy synthesis of M/N-C hybrids in high yield, which includes a mussel-inspired polymerization reaction at room temperature and a subsequent carbonization process. With the introduction of selected transition metal salts into an aqueous solution of dopamine (DA), the obtained mixture self-polymerizes to form metal-containing polydopamine (M-PDA) composites, e.g. Co-PDA, Ni-PDA and Fe-PDA. Upon carbonization at elevated temperatures, these metal-containing composites were converted into M/N-C, i.e. Co-PDA-C, Ni-PDA-C and Fe-PDA-C, respectively, whose morphologies, chemical compositions, and electrochemical performances were fully studied. Enhanced ORR activities were found in all the obtained hybrids, with Co-PDA-C standing out as the most promising catalyst with excellent stability and catalytic activities towards both ORR and OER. This was further proven in Zn-air batteries (ZnABs) in terms of discharge voltage stability and cycling performance. At a discharge-charge current density of 2 mA cm-2 and 1 h per cycle, the Co-PDA-C based ZnABs were able to steadily cycle up to 500 cycles with only a small increase in the discharge-charge voltage gap which notably outperformed Pt/C; at a discharge current density of 5 mA cm-2, the battery continuously discharged for more than 540 h with the discharge voltage above 1 V and a voltage drop rate of merely 0.37 mV h-1. With the simplicity and scalability of the synthetic approach and remarkable battery performances, the Co-PDA-C hybrid catalyst is anticipated to play an important role in practical ZnABs.Transition metal and nitrogen co-doping into carbon is an effective

  19. Mussel-inspired one-pot synthesis of transition metal and nitrogen co-doped carbon (M/N-C) as efficient oxygen catalysts for Zn-air batteries

    NASA Astrophysics Data System (ADS)

    Li, Bing; Chen, Ye; Ge, Xiaoming; Chai, Jianwei; Zhang, Xiao; Hor, T. S. Andy; Du, Guojun; Liu, Zhaolin; Zhang, Hua; Zong, Yun

    2016-02-01

    Transition metal and nitrogen co-doping into carbon is an effective approach to promote the catalytic activities towards the oxygen reduction reaction (ORR) and/or oxygen evolution reaction (OER) in the resultant electrocatalysts, M/N-C. The preparation of such catalysts, however, is often complicated and in low yield. Herein we report a robust approach for easy synthesis of M/N-C hybrids in high yield, which includes a mussel-inspired polymerization reaction at room temperature and a subsequent carbonization process. With the introduction of selected transition metal salts into an aqueous solution of dopamine (DA), the obtained mixture self-polymerizes to form metal-containing polydopamine (M-PDA) composites, e.g. Co-PDA, Ni-PDA and Fe-PDA. Upon carbonization at elevated temperatures, these metal-containing composites were converted into M/N-C, i.e. Co-PDA-C, Ni-PDA-C and Fe-PDA-C, respectively, whose morphologies, chemical compositions, and electrochemical performances were fully studied. Enhanced ORR activities were found in all the obtained hybrids, with Co-PDA-C standing out as the most promising catalyst with excellent stability and catalytic activities towards both ORR and OER. This was further proven in Zn-air batteries (ZnABs) in terms of discharge voltage stability and cycling performance. At a discharge-charge current density of 2 mA cm-2 and 1 h per cycle, the Co-PDA-C based ZnABs were able to steadily cycle up to 500 cycles with only a small increase in the discharge-charge voltage gap which notably outperformed Pt/C; at a discharge current density of 5 mA cm-2, the battery continuously discharged for more than 540 h with the discharge voltage above 1 V and a voltage drop rate of merely 0.37 mV h-1. With the simplicity and scalability of the synthetic approach and remarkable battery performances, the Co-PDA-C hybrid catalyst is anticipated to play an important role in practical ZnABs.Transition metal and nitrogen co-doping into carbon is an effective

  20. Nonflammable organic-base paint for oxygen-rich atmospheres

    NASA Technical Reports Server (NTRS)

    Harwell, R. J.; Key, C. F.; Krupnick, A. C.

    1971-01-01

    New paint formulations, which combine aqueous latex paints with inorganic pigments and additives, produce coatings that are self-extinguishing in pure oxygen at pressures up to twice the partial pressure of atmospheric oxygen. A paint formulation in percent by weight is given and the properties of resultant coatings are discussed.

  1. Oxygen Transport Ceramic Membranes

    SciTech Connect

    S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

    2006-05-01

    In this quarter a systematic analysis on the decomposition behavior of the OTM membranes at air and nitrogen were initiated to understand the structural and stoichiometric changes associated with elevated temperatures. Evaluation of the flexural strengths using 4-point bend test was also started for the dual phase membranes. Initial results on the synthesis of dual phase composite materials have been obtained. The measurements have focused on the compatibility of mixed conductors with the pure ionic conductors yttria stabilized zirconia (YSZ) and gadolinium doped ceria (GDC). The initial results obtained for three different mixed conductors suggest that (GDC) is the better choice. A new membrane permeation system has been designed and tested and sintering studies of biphasic systems are in progress.

  2. A 400 year reconstruction of July relative air humidity for the region Vienna (eastern Austria) based on carbon and oxygen stable isotope ratios in tree-ring latewood cellulose of oaks

    NASA Astrophysics Data System (ADS)

    Haupt, M.; Boettger, T.; Weigl, M.; Grabner, M.

    2009-04-01

    Stable isotope chronologies and correlation to climate. We present the stable isotope chronologies of carbon (^13Clw) and oxygen (^18Olw) for the period from 1600 to 2003 respectively of non-exchangeable hydrogen (^2Hlw) for the last century constructed base upon tree-ring latewood cellulose from oaks (Quercus petraea Matt. Liebl.) grown in the region Vienna (Austria). The stable isotope ratios correspond mainly to the summer climate conditions. For the calibration period (1900-2003) we found high significant correlations (p < 0.001) between ^13Clw and relative air humidity (RH) of July (-0.66), between ^18Olw and RHV I-V II (-0.61) and between ^2Hlw and RHV I-V III(-0.56). In the case of temperatures high significant correlations between the growing season temperature and ^13Clw (0.55), between the annual mean temperatures and ^18Olw ratios (0.45) and between summer mean temperatures (June to August) and ^2Hlw values (0.49) were estimated. Modeling. Various univariate and multivariate linear regressions models were proved for the reconstruction of summer relative air humidity and temperature. We found that establishing of robust models had several uncertainties: - using common linear transfer functions which oversimplify the complexity of relations; - using of pooled material and neglecting of different reactions from individual trees to climate; - high-order autocorrelations in the isotope time series; - climatic trends in the investigated region which are different in the first and in the second half of 20th century; - temporal instability of climate signals in the isotope ratios of tree ring cellulose. In the case of temperature no valid model could be estimated caused by temporal instabilities of signal strength. For relative air humidity two bivariate models RHV II = (-4.3 ± 0.7) * ^13Clw + (-2.8 ± 0.5) * ^18Olw + 44 [1] and RHV II = (-4.7 ± 0.7) * ^13Clw + (-0.35 ± 0.07) * ^2Hlw - 68 [2] were found as verifiable and applicable to reconstruct RHV II

  3. A 400 year reconstruction of July relative air humidity for the region Vienna (eastern Austria) based on carbon and oxygen stable isotope ratios in tree-ring latewood cellulose of oaks

    NASA Astrophysics Data System (ADS)

    Haupt, M.; Boettger, T.; Weigl, M.; Grabner, M.

    2009-04-01

    Stable isotope chronologies and correlation to climate. We present the stable isotope chronologies of carbon (^13Clw) and oxygen (^18Olw) for the period from 1600 to 2003 respectively of non-exchangeable hydrogen (^2Hlw) for the last century constructed base upon tree-ring latewood cellulose from oaks (Quercus petraea Matt. Liebl.) grown in the region Vienna (Austria). The stable isotope ratios correspond mainly to the summer climate conditions. For the calibration period (1900-2003) we found high significant correlations (p < 0.001) between ^13Clw and relative air humidity (RH) of July (-0.66), between ^18Olw and RHV I-V II (-0.61) and between ^2Hlw and RHV I-V III(-0.56). In the case of temperatures high significant correlations between the growing season temperature and ^13Clw (0.55), between the annual mean temperatures and ^18Olw ratios (0.45) and between summer mean temperatures (June to August) and ^2Hlw values (0.49) were estimated. Modeling. Various univariate and multivariate linear regressions models were proved for the reconstruction of summer relative air humidity and temperature. We found that establishing of robust models had several uncertainties: - using common linear transfer functions which oversimplify the complexity of relations; - using of pooled material and neglecting of different reactions from individual trees to climate; - high-order autocorrelations in the isotope time series; - climatic trends in the investigated region which are different in the first and in the second half of 20th century; - temporal instability of climate signals in the isotope ratios of tree ring cellulose. In the case of temperature no valid model could be estimated caused by temporal instabilities of signal strength. For relative air humidity two bivariate models RHV II = (-4.3 ± 0.7) * ^13Clw + (-2.8 ± 0.5) * ^18Olw + 44 [1] and RHV II = (-4.7 ± 0.7) * ^13Clw + (-0.35 ± 0.07) * ^2Hlw - 68 [2] were found as verifiable and applicable to reconstruct RHV II

  4. Oxygen supply in Bacillus thuringiensis fermentations: bringing new insights on their impact on sporulation and δ-endotoxin production.

    PubMed

    Boniolo, Fabrízio Siqueira; Rodrigues, Raphael Cardoso; Prata, Arnaldo Márcio Ramalho; López, Maria Luisa; Jacinto, Tânia; da Silveira, Mauricio Moura; Berbert-Molina, Marília Amorim

    2012-05-01

    The growth kinetics, sporulation, and toxicity of Bacillus thuringiensis var. israelensis were evaluated through the analysis of batch cultures with different dissolved oxygen (DO) profiles. Firstly, DO was maintained constant at 5%, 20%, or 50% throughout fermentation in order to identify the most suitable one to improve the main process parameters. Higher biomass concentration, cell productivity, and cell yield based on glucose were obtained with 50% DO. The higher aeration level also resulted in higher spore counts and markedly improved the toxic activity of the fermentation broth, which was 9-fold greater than that obtained with 5% DO (LC(50) of 39 and 329 mg/L, respectively). Subsequently, using a two-stage oxygen supply strategy, DO was kept at 50% during the vegetative and transition phases until the maximum cell concentration was achieved. Then, DO was changed to 0%, 5%, 20%, or 100% throughout sporulation and cell lysis phases. The interruption of oxygen supply strongly reduced the spore production and thoroughly repressed the toxin synthesis. On the contrary, when DO was raised to 100% of saturation, toxic activity increased approximately four times (LC(50) of 8.2 mg/L) in comparison with the mean values reached with lower DO levels, even though spore counts were lower than that from the 50% DO assay. When pure oxygen was used instead of normal air, it was possible to obtain 70% of the total biomass concentration achieved in the air assays; however, cultures did not sporulate and the toxin synthesis was consequently suppressed. PMID:22395904

  5. Deposition of pure gold thin films from organometallic precursors

    NASA Astrophysics Data System (ADS)

    Parkhomenko, Roman G.; Trubin, Sergey V.; Turgambaeva, Asiya E.; Igumenov, Igor К.

    2015-03-01

    Using metallorganic chemical vapor deposition, pure gold thin films have been obtained from a number of volatile dimethylgold(III) complexes with different types of chelating organic ligands. Deposition was performed in argon (10 Torr) with and without hydrogen and oxygen as reactant gases and with additional VUV (vacuum ultraviolet) stimulation. According to the XRD phase analysis, gold films grow mainly in [111] direction. The influence of precursor structure on the morphology of the deposited layers was demonstrated. It was established that presence of H2 raises the growth rate and porosity of the films significantly with decreased amount of any impurities. With the VUV stimulation, the gold content in the films amounts to >99 at%.

  6. Ab initio charge analysis of pure and hydrogenated perovskites

    NASA Astrophysics Data System (ADS)

    Bork, N.; Bonanos, N.; Rossmeisl, J.; Vegge, T.

    2011-02-01

    We present a density functional theory based Bader analysis of the charge distribution in pure and hydrogenated SrTiO3. We find that the hydrogen defect carries a +0.56e charge and the OH defect carries a +0.50e charge compared to the host oxygen. Calculations on BaNbO3, CaTiO3, and SrZrO3 support these findings. The distribution of the remaining electronic density decays exponentially with distance to the hydrogen defect. Diffusional paths are calculated wherein the hydrogenic species retain a charge between +0.57 and +0.54e showing that hydrogen permeation should not be viewed as consisting of virtually independent protonic and electronic transport processes.

  7. Nokia PureView oversampling technology

    NASA Astrophysics Data System (ADS)

    Vuori, Tero; Alakarhu, Juha; Salmelin, Eero; Partinen, Ari

    2013-03-01

    This paper describes Nokia's PureView oversampling imaging technology as well as the product, Nokia 808 PureView, featuring it. The Nokia PureView imaging technology is the combination of a large, super high resolution 41Mpix with high performance Carl Zeiss optics. Large sensor enables a pixel oversampling technique that reduces an image taken at full resolution into a lower resolution picture, thus achieving higher definition and light sensitivity. One oversampled super pixel in image file is formed by using many sensor pixels. A large sensor enables also a lossless zoom. If a user wants to use the lossless zoom, the sensor image is cropped. However, up-scaling is not needed as in traditional digital zooming usually used in mobile devices. Lossless zooming means image quality that does not have the digital zooming artifacts as well as no optical zooming artifacts like zoom lens system distortions. Zooming with PureView is also completely silent. PureView imaging technology is the result of many years of research and development and the tangible fruits of this work are exceptional image quality, lossless zoom, and superior low light performance.

  8. Oxygen rotational temperature determination using empirical analyses of C(3)Π(v' = 2) ← X(3)Σ(v'' = 0) transitions.

    PubMed

    Adams, Steven F; Wu, Yue; Zhang, Zhili

    2015-09-01

    The spectra of molecular oxygen through C(3)Π(v' = 2) ← X(3)Σ(v'' = 0) transitions have been obtained by coherent microwave Rayleigh scattering (radar) from resonance-enhanced multiphoton ionization (REMPI). Measurements of rotational temperatures of molecular oxygen have been demonstrated based on the empirical analyses of the O2 spectra without the requirement of highly resolved rotational features. Three methods, including (1) linewidth fitting, (2) linear fitting, and (3) area fitting have been investigated for temperature measurements within pure oxygen, ambient air, and H2-air and CH4-air flame environments. The first two methods were applied in a moderately low temperature environment with measurement uncertainties less than 11% and 26%, respectively. The area fitting method covered a wider temperature range, from room temperature (~300 K) to flame temperature (~1700 K), with minimal dependence on the fine structures of the O2 spectra. Less elaborate than Boltzmann plot analyses of ultrafine rotational lines from congested upper rotational energy levels in O2(C(3)Π(v' = 2)), these empirical analyses are predictably sensitive to the thermal distribution of molecular oxygen and have been successfully demonstrated as simple and quick methods for remote gas-phase temperature measurement. PMID:26414523

  9. Double-grating monochromator for a pure rotational Raman lidar

    NASA Astrophysics Data System (ADS)

    Ansmann, Albert; Arshinov, Yuri; Bobrovnikov, Sergey M.; Mattis, Ina; Serikov, Il'ya B.; Wandinger, Ulla

    1999-01-01

    We propose a new optical arrangement of the double grating monochromator (DGRM), intended for use in a pure rotational Raman-lidar. The main idea of the construction proposed is in the use of optical monofibers, to couple two chambers of the DGRM. The coupling with optical monofibers enables isolation of two pairs of spectral portions in the S and O branches of the pure rotational Raman spectra (PRRS) of nitrogen and oxygen symmetric relative to the line of exciting radiation. The use of monofibers provides for optically summing the symmetric portions of the PRRS at the exit of the second monochromator, thus increasing the power of PRRS collected for further temperature retrieval. It is important that this approach provides for better than 107 suppression of the spectral line, due to unshifted Mie+Rayleigh scattering. As calculations and laboratory experiments show the end-to-end transmission of the DGRM, with the account of optical summing mentioned, can compare with the transmission of the interference filters available. At the same time, the DGRM provides better spectral purity of the RRS portions isolated, which is a crucial point of the Raman-lidar temperature measurements. Temperature profiles of the atmosphere acquired with the combined Raman- lidar of the Institute for Tropospheric Research in Leipzig, Germany, equipped with the DGRM proposed, showed a good agreement with the profiles measured with a radiosonge.

  10. All-solid-state lithium-oxygen battery with high safety in wide ambient temperature range

    NASA Astrophysics Data System (ADS)

    Kitaura, Hirokazu; Zhou, Haoshen

    2015-08-01

    There is need to develop high energy storage devices with high safety to satisfy the growing industrial demands. Here, we show the potential to realize such batteries by assembling a lithium-oxygen cell using an inorganic solid electrolyte without any flammable liquid or polymer materials. The lithium-oxygen battery using Li1.575Al0.5Ge1.5(PO4)3 solid electrolyte was examined in the pure oxygen atmosphere from room temperature to 120 °C. The cell works at room temperature and first full discharge capacity of 1420 mAh g-1 at 10 mA g-1 (based on the mass of carbon material in the air electrode) was obtained. The charge curve started from 3.0 V, and that the majority of it lay below 4.2 V. The cell also safely works at high temperature over 80 °C with the improved battery performance. Furthermore, fundamental data of the electrochemical performance, such as cyclic voltammogram, cycle performance and rate performance was obtained and this work demonstrated the potential of the all-solid-state lithium-oxygen battery for wide temperature application as a first step.

  11. Production of NO2/-/ and N2O by nitrifying bacteria at reduced concentrations of oxygen

    NASA Technical Reports Server (NTRS)

    Goreau, T. J.; Kaplan, W. A.; Wofsy, S. C.; Mcelroy, M. B.; Valois, F. W.; Watson, S. W.

    1980-01-01

    The influence of oxygen concentration on the production of NO2(-) and N2O by nitrifying marine bacteria of the genus Nitrosomonas is investigated. Pure cultures of the ammonium-oxiding bacteria isolated from the Western Tropical Atlantic Ocean were grown at oxygen partial pressures from 0.005 to 0.2 atm, and concentrations of N2O in the air above the growth medium and dissolved NO2(-) were determined. Decreasing oxygen concentrations are observed to induce a marked decrease in NO2(-) production rates and increase in N2O evolution, leading to an increase of the relative yield of N2O with respect to NO2(-) from 0.3% to nearly 10%. Similar yields of N2O at atmospheric oxygen levels are found for nitrifying bacteria of the genera Nitrosomonas, Nitrosolobus, Nitrosospira and Nitrosococcus, while nitrite-oxydizing bacteria and a dinoflagellate did not produce detectable quantities of N2O. Results support the view that nitrification is a major source of N2O in the environment.

  12. All-solid-state lithium-oxygen battery with high safety in wide ambient temperature range.

    PubMed

    Kitaura, Hirokazu; Zhou, Haoshen

    2015-01-01

    There is need to develop high energy storage devices with high safety to satisfy the growing industrial demands. Here, we show the potential to realize such batteries by assembling a lithium-oxygen cell using an inorganic solid electrolyte without any flammable liquid or polymer materials. The lithium-oxygen battery using Li1.575Al0.5Ge1.5(PO4)3 solid electrolyte was examined in the pure oxygen atmosphere from room temperature to 120 °C. The cell works at room temperature and first full discharge capacity of 1420 mAh g(-1) at 10 mA g(-1) (based on the mass of carbon material in the air electrode) was obtained. The charge curve started from 3.0 V, and that the majority of it lay below 4.2 V. The cell also safely works at high temperature over 80 °C with the improved battery performance. Furthermore, fundamental data of the electrochemical performance, such as cyclic voltammogram, cycle performance and rate performance was obtained and this work demonstrated the potential of the all-solid-state lithium-oxygen battery for wide temperature application as a first step. PMID:26293134

  13. All-solid-state lithium-oxygen battery with high safety in wide ambient temperature range

    PubMed Central

    Kitaura, Hirokazu; Zhou, Haoshen

    2015-01-01

    There is need to develop high energy storage devices with high safety to satisfy the growing industrial demands. Here, we show the potential to realize such batteries by assembling a lithium-oxygen cell using an inorganic solid electrolyte without any flammable liquid or polymer materials. The lithium-oxygen battery using Li1.575Al0.5Ge1.5(PO4)3 solid electrolyte was examined in the pure oxygen atmosphere from room temperature to 120 °C. The cell works at room temperature and first full discharge capacity of 1420 mAh g−1 at 10 mA g−1 (based on the mass of carbon material in the air electrode) was obtained. The charge curve started from 3.0 V, and that the majority of it lay below 4.2 V. The cell also safely works at high temperature over 80 °C with the improved battery performance. Furthermore, fundamental data of the electrochemical performance, such as cyclic voltammogram, cycle performance and rate performance was obtained and this work demonstrated the potential of the all-solid-state lithium-oxygen battery for wide temperature application as a first step. PMID:26293134

  14. [Study of pure titanium electrolytic polishing].

    PubMed

    Morita, N

    1990-03-01

    This study attempted to polish pure titanium test pieces electrolytically to mirror surface at the size of cast denture frames. Electrolytic polishing of pure titanium could be done on an area of 30 cm2 with a non-aqueous electrolyte. Small pure titanium plates could be polished electrolytically, but a uniformly smooth surface could not be obtained easily with large testpiece. The optimal electrolytic conditions were 30 V for 6 min at 25 degrees C using a solution consisting of 70 ml ethyl alcohol, 30 ml iso-propyl alcohol, 6 g aluminum chloride, and 25 g zinc chloride. The solution was safe and had less restriction of frequency of use. PMID:2135513

  15. Engineering arbitrary pure and mixed quantum states

    SciTech Connect

    Pechen, Alexander

    2011-10-15

    Controlled manipulation by atomic- and molecular-scale quantum systems has attracted a lot of research attention in recent years. A fundamental problem is to provide deterministic methods for controlled engineering of arbitrary quantum states. This work proposes a deterministic method for engineering arbitrary pure and mixed states of a wide class of quantum systems. The method exploits a special combination of incoherent and coherent controls (incoherent and coherent radiation) and has two properties which are specifically important for manipulating by quantum systems: it realizes the strongest possible degree of their state control, complete density matrix controllability, meaning the ability to steer arbitrary pure and mixed initial states into any desired pure or mixed final state, and it is all-to-one, such that each particular control transfers all initial system states into one target state.

  16. Surface vibrational spectroscopy of pure liquids

    SciTech Connect

    Superfine, R.; Huang, J.Y.; Du, Q.; Shen, Y.R.

    1991-03-01

    We report the use of infrared visible sum frequency generation (SFG) to obtain the surface vibrational spectra of pure liquid methanol and water. These are the first surface vibrational spectra ever obtained for pure liquids. We have also deduced from the SFG results the absolute orientations of molecules at the pure liquid/vapor interface. The surface methanol molecules appear to have their CH{sub 3} groups projecting out of the liquid in agreement with the theoretical prediction. For the orientation of surface water molecules, however, different calculations have yielded very different predictions. Our SFG measurement provides clear evidence that the molecules are oriented with an unbonded hydrogen projecting out of the liquid. 9 refs., 3 figs.

  17. Soot formation and temperature structure in small methane-oxygen diffusion flames at subcritical and supercritical pressures

    SciTech Connect

    Joo, Hyun I.; Guelder, Oemer L.

    2010-06-15

    An experimental study was conducted to examine the characteristics of laminar methane-oxygen diffusion flames up to 100 atmospheres. The influence of pressure on soot formation and on the structure of the temperature field was investigated over the pressure range of 10-90 atmospheres in a high-pressure combustion chamber using a non-intrusive, line-of-sight spectral soot emission diagnostic technique. Two distinct zones characterized the appearance of a methane and pure oxygen diffusion flame: an inner luminous zone similar to the methane-air diffusion flames, and an outer diffusion flame zone which is mostly blue. The flame height, marked by the visible soot radiation emission, was reduced by over 50% over the pressure range of 10-100 atmospheres. Between 10 and 40 atmospheres, the soot levels increased with increasing pressure; however, above 40 atmospheres the soot concentrations decreased with increasing pressure. (author)

  18. Pure neuritic leprosy: Current status and relevance.

    PubMed

    Rao, P Narasimha; Suneetha, Sujai

    2016-01-01

    Pure neuritic leprosy has always been an enigma due to its clinical and management ambiguities. Although only the Indian Association of Leprologist's classification recognizes 'pure neuritic leprosy' as a distinct sub group of leprosy, cases nonetheless are reported from various countries of Asia, Africa, South America and Europe, indicating its global relevance. It is important to maintain pure neuritic leprosy as a subgroup as it constitutes a good percentage of leprosy cases reported from India, which contributes to more than half of global leprosy numbers. Unfortunately, a high proportion of these patients present with Grade 2 disability at the time of initial reporting itself due to the early nerve involvement. Although skin lesions are absent by definition, when skin biopsies were performed from the skin along the distribution of the affected nerve, a proportion of patients demonstrated leprosy pathology, revealing sub-clinical skin involvement. In addition on follow-up, skin lesions are noted to develop in up to 20% of pure neuritic leprosy cases, indicating its progression to manifest cutaneous disease. Over the decades, the confirmation of diagnosis of pure neuritic leprosy has been subjective, however, with the arrival and use of high-resolution ultrasonography (HRUS) for nerve imaging, we have a tool not only to objectively measure and record the nerve thickening but also to assess the morphological alterations in the nerve including echo texture, fascicular pattern and vascularity. Management of pure neuritic leprosy requires multidrug therapy along with appropriate dose of systemic corticosteroids, for both acute and silent neuritis. Measures for pain relief, self-care of limbs and physiotherapy are important to prevent as well as manage disabilities in this group of patients. PMID:27088926

  19. Monitoring oxygenation.

    PubMed

    Severinghaus, John W

    2011-06-01

    Cyanosis was used for a century after dentists began pulling teeth under 100% N(2)O in 1844 because brief (2 min) severe hypoxia is harmless. Deaths came with curare and potent anesthetic respiratory arrest. Leland Clark's invention of a polarographic blood oxygen tension electrode (1954) was introduced for transcutaneous PO2 monitoring to adjust PEEP and CPAP PO2 to prevent premature infant blindness from excess O2 (1972). Oximetry for warning military aviators was tried after WW II but not used for routine monitoring until Takuo Aoyagi (1973) discovered an equation to measure SaO2 by the ratio of ratios of red and IR light transmitted through tissue as it changed with arterial pulses. Pulse oximetry (1982) depended on simultaneous technology improvements of light emitting red and IR diodes, tiny cheap solid state sensors and micro-chip computers. Continuous monitoring of airway anesthetic concentration and oxygen also became very common after 1980. Death from anesthesia fell 10 fold between 1985 and 2000 as pulse oximetry became universally used, but no proof of a causative relationship to pulse oximetry exists. It is now assumed that all anesthesiologist became much more aware of the dangers of prolonged hypoxia, perhaps by using the pulse oximeters. PMID:21717228

  20. Effects of oxygen on fracturing fluids

    SciTech Connect

    Walker, M.L.; Shuchart, C.E.; Yaritz, J.G.; Norman, L.R.

    1995-11-01

    The stability of polysaccharide gels at high temperature is limited by such factors as pH, mechanical degradation, and oxidants. Oxygen is unavoidably placed in fracturing fluids through dissolution of air. To prevent premature degradation of the fracturing fluid by this oxidant, oxygen scavengers are commonly used. In this paper, the effects of oxygen and various oxygen scavengers on gel stability will be presented. Mechanical removal of oxygen resulted in surprisingly stable fracturing gels at 275 F. However, chemical removal of oxygen gave mixed results. Test data from sodium thiosulfate, sodium sulfite, and sodium erythorbate used as oxygen scavengers/gel stabilizers showed that the efficiency of oxygen removal from gels did not directly coincide with the viscosity retention of the gel, and large excesses of additives were necessary to provide optimum gel stabilization. The inability of some oxygen scavengers to stabilize the gel was the result of products created from the interaction of oxygen with the oxygen scavenger, which in turn, produced species that degraded the gel. The ideal oxygen scavenger should provide superior gel stabilization without creating detrimental side reaction products. Of the materials tested, sodium thiosulfate appeared to be the most beneficial.

  1. Co(II)1-xCo(0)x/3Mn(III)2x/3S Nanoparticles Supported on B/N-Codoped Mesoporous Nanocarbon as a Bifunctional Electrocatalyst of Oxygen Reduction/Evolution for High-Performance Zinc-Air Batteries.

    PubMed

    Wang, Zilong; Xiao, Shuang; An, Yiming; Long, Xia; Zheng, Xiaoli; Lu, Xihong; Tong, Yexiang; Yang, Shihe

    2016-06-01

    Rechargeable Zn-air battery is an ideal type of energy storage device due to its high energy and power density, high safety, and economic viability. Its large-scale application rests upon the availability of active, durable, low-cost electrocatalysts for the oxygen reduction reaction (ORR) in the discharge process and oxygen evolution reaction (OER) in the charge process. Herein we developed a novel ORR/OER bifunctional electrocatalyst for rechargeable Zn-air batteries based on the codoping and hybridization strategies. The B/N-codoped mesoporous nanocarbon supported Co(II)1-xCo(0)x/3Mn(III)2x/3S nanoparticles exhibit a superior OER performance compared to that of IrO2 catalyst and comparable Zn-air battery performance to that of the Pt-based battery. The rechargeable Zn-air battery shows high discharge peak power density (over 250 mW cm(-2)) and current density (180 mA cm(-2) at 1 V), specific capacity (∼550 mAh g(-1)), small charge-discharge voltage gap of ∼0.72 V at 20 mA cm(-2) and even higher stability than the Pt-based battery. The advanced performance of the bifunctional catalysts highlights the beneficial role of the simultaneous formation of Mn(III) and Co(0) as well as the dispersed hybridization with the codoped nanocarbon support. PMID:27163673

  2. BRST and the pure spinor formalism

    SciTech Connect

    Garcia, J. Antonio

    2008-03-06

    The aim of this talk is to show the relation between the standard BRST approach of the GS superstring with the quantization technics used in the pure spinor approach to superstring. To that end we will use the Batalin-Fradkin-Tyutin (BFT) conversion program of second class constraints to first class constraints in the GS superstring using light cone coordinates. By applying this systematic procedure we were able to obtain a gauge system that is equivalent to the recent model proposed in [1] to relate the GS superstring to the pure spinor formalism.

  3. Ecophysiological and Phylogenetic Studies of Nevskia ramosa in Pure Culture

    PubMed Central

    Stürmeyer, Heike; Overmann, Jörg; Babenzien, Hans-Dietrich; Cypionka, Heribert

    1998-01-01

    During the last 100 years, the neuston bacterium Nevskia ramosa has been described several times. This bacterium forms conspicuous rosette-like microcolonies at the air-water interface. In this study, pure cultures of Nevskia ramosa were obtained for the first time, from a bog lake (strain Soe1, DSMZ 11499T) and a freshwater ditch (strain OL1, DSMZ 11500). The isolates showed special adaptations to life in the epineuston. They formed hydrophobic surface films with a dull appearance. N. ramosa is sensitive to UV radiation but revealed a very effective photorepair mechanism. Exposure to light at a wavelength of 350 nm after UV treatment raised the number of surviving cells by several orders of magnitude. The isolates grew with a broad range of organic substrates. Surface films were formed only in the absence of combined nitrogen; however, nitrogenase activity was not detected. It appears that during growth at the air-water interface the cells benefit from trapping ammonia from the air. The G+C content of the DNA was 67.8 and 69.0 mol% for strains Soe1 and OL1, respectively. The slight difference was confirmed by enterobacterial repetitive intergenic consensus PCR. The 16S rRNA sequences revealed 99.2% similarity. Thus, both isolates belong to the same species. The phylogenetic analysis indicated that Nevskia is a member of the gamma-subclass Proteobacteria that has no known close relatives. PMID:9572968

  4. Effect of oxygen on the ignition of liquid fuels

    NASA Technical Reports Server (NTRS)

    Pahl, H

    1929-01-01

    The ignition temperature, ignition lag, and ignition strength of simple and homogeneous fuels in combustion air of small oxygen content differ from what they are in air of greater oxygen content. In the case of small oxygen content, these fuels behave as if mixed unevenly. In the case of air with a definite oxygen content, the simple fuels have two ignition points, between which ignition takes place within a certain temperature range. The phenomena are explained by pyrogenous decomposition, comparison of the individual heat quantities, and the effect of the walls.

  5. Molecular tectonics: from enantiomerically pure sugars to enantiomerically pure triple stranded helical coordination network.

    PubMed

    Grosshans, Philippe; Jouaiti, Abdelaziz; Bulach, Véronique; Planeix, Jean-Marc; Hosseini, Mir Wais; Nicoud, Jean-François

    2003-06-21

    The self-assembly between a bis-monodentate tecton based on two pyridine units connected to an enantiomerically pure isomannide stereoisomer and HgCl2 leads to the formation of an enantiomerically pure triple stranded helical infinite coordination network which was structurally characterised by X-ray diffraction on single crystal. PMID:12841229

  6. Comparison of airline passenger oxygen systems.

    PubMed

    Byrne, N J

    1995-08-01

    The principal sources of oxygen for inflight passenger use, scheduled and unscheduled, are examined. Present practices of assessment of the passenger's "fitness to fly" are described. Three partner airlines, British Airways, U.S. Air, and Qantas, catering for more than 8000 oxygen requests annually, are compared. Analysis of customer use suggests that medical oxygen requests are frequently not clinically justified. The growth in demand, for both scheduled and unscheduled use of an expensive resource, supports the need for a "recommended best practice" among carriers. Passengers with respiratory disorders who will most benefit from inflight oxygen are vulnerable either to hypoxia or asthma. PMID:7487813

  7. SAFETY ASPECTS OF OXYGEN AERATION ACTIVATED SLUDGE SYSTEMS

    EPA Science Inventory

    This project was carried out to assess the impact of the use of oxygen and oxygen-enriched air for aeration of activated sludge systems on the safety of municipal waste-water treatment plants and their personnel. The tasks included (1) determination of oxygen combustion hazards f...

  8. 114. WEST SIDE OF LIQUID OXYGEN CONTROL ROOM (205). LIQUID ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    114. WEST SIDE OF LIQUID OXYGEN CONTROL ROOM (205). LIQUID NITROGEN (LN2) SUBCOOLER ON LEFT; SKID 8, LIQUID OXYGEN CONTROLLER FOR SWITCHING BETWEEN RAPID-LOAD AND TOPPING ON RIGHT. LIQUID OXYGEN LINE FROM SKID 9A AT RIGHT EDGE OF PHOTO. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  9. Influence of oxygen supply on heptadecane mineralization by Pseudomonas nautica.

    PubMed

    Bonin, P; Bertrand, J C

    2000-11-01

    The influence of different states of oxygen supply on heptadecane mineralization has been investigated in resting cell suspensions of Pseudomonas nautica. The rate of heptadecane biodegraded was constant for oxygen concentrations between 21% and 10% (v/v) (about 100% and 50% of air saturation, 230 and 110 microM, respectively). A decline in biodegradation rates occurred for oxygen concentrations below 10% (about 50% of air saturation, 110 microM) and biodegradation stopped with 0.21% oxygen (2.3 microM). In the presence of 1% (11 microM) of oxygen, no CO2 was produced, showing that complete mineralisation of heptadecane was blocked. PMID:11057567

  10. Research on rechargeable oxygen electrodes.

    NASA Technical Reports Server (NTRS)

    Giner, J.; Holleck, G.; Malachesky, P. A.

    1970-01-01

    A research program is described which consisted of studying the effects of electrode cycling in very pure KOH solutions, with and without controlled additions of impurities, on oxide formation, oxygen evolution kinetics, oxygen reduction kinetics (including hydrogen peroxide formation), and changes in electrode structure. Bright platinum, platinized platinum, and Teflon-bonded platinum black electrodes were studied. Three main problem areas are identified: the buildup of a refractory anodic layer on prolonged cycling, which leads to a degradation of performance; the dissolution and subsequent deposition of dendritic platinum in the separator, leading to short-circuit ing and loss of electrocatalyst; and the disruptive effect of bubbling during gas evolution on charge. Each of these problem areas is analyzed, and remedial solutions are proposed.

  11. Air Pollution

    MedlinePlus

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, dust, ... a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  12. Air Pollution

    MedlinePlus

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, ... Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  13. Temporal Ventriloquism in a Purely Temporal Context

    ERIC Educational Resources Information Center

    Hartcher-O'Brien, Jessica; Alais, David

    2011-01-01

    This study examines how audiovisual signals are combined in time for a temporal analogue of the ventriloquist effect in a purely temporal context, that is, no spatial grounding of signals or other spatial facilitation. Observers were presented with two successive intervals, each defined by a 1250-ms tone, and indicated in which interval a brief…

  14. Thrust Measurement of Pure Magnetic Sail

    NASA Astrophysics Data System (ADS)

    Ueno, Kazuma; Kimura, Toshiyuki; Ayabe, Tomohiro; Funaki, Ikkoh; Yamakawa, Hiroshi; Horisawa, Hideyuki

    A Pure Magnetic Sail is a deep space propulsion system consisting of a coil mounted on a spacecraft. In order to predict the thrust characteristics of a Pure Magnetic Sail in space, thrust measurement and magnetic field measurement were conducted using a scale model in a laboratory. To simulate the solar wind, a magnetoplasmadynamic arcjet provides a high density (2×1019 m-3) and high velocity (47 km/s) plasma flow that impinges on a 20-turn 25-mm-radius coil simulating a Pure Magnetic Sail. When the magnetic cavity size of the scale model (L) is increased from 0.12 to 0.17 m, the thrust increases from 0.47 to 0.92 N. Scaling up, this experiment corresponds to a 300-km diameter Pure Magnetic Sail in space. The thrust also depends on the coil tilt angle, which is the angle between the direction of the solar wind flow and the coil axis. The maximum thrust of 1.5 N is obtained for a tilt angle of 90 degrees.

  15. Implicit Reading in Chinese Pure Alexia

    ERIC Educational Resources Information Center

    Shan, Chunlei; Zhu, Renjing; Xu, Mingwei; Luo, Benyan; Weng, Xuchu

    2010-01-01

    A number of recent studies have shown that some patients with pure alexia display evidence of implicit access to lexical and semantic information about words that they cannot read explicitly. This phenomenon has not been investigated systematically in Chinese patients. We report here a case study of a Chinese patient who met the criteria for pure…

  16. Exploring the simplest purely baryonic decay processes

    NASA Astrophysics Data System (ADS)

    Geng, C. Q.; Hsiao, Y. K.; Rodrigues, Eduardo

    2016-07-01

    Though not considered in general, purely baryonic decays could shed light on the puzzle of the baryon number asymmetry in the universe by means of a better understanding of the baryonic nature of our matter world. As such, they constitute a yet unexplored class of decay processes worth investigating. We propose to search for purely baryonic decay processes at the LHCb experiment. No such type of decay has ever been observed. In particular, we concentrate on the decay Λb0→p p ¯n , which is the simplest purely baryonic decay mode, with solely spin-1 /2 baryons involved. We predict its decay branching ratio to be B (Λb0→p p ¯ n )=(2. 0-0.2+0.3)×10-6 , which is sufficiently large to make the decay mode accessible to LHCb. Our study can be extended to other purely baryonic decays such as Λb0→p p ¯ Λ , Λb0→Λ p ¯ Λ , and Λb0→Λ Λ ¯Λ , as well as to similar decays of antitriplet b baryons such as Ξb0 ,-.

  17. A Pure Theory of Lifelong Learning.

    ERIC Educational Resources Information Center

    Hatton, Michael J.

    Charles Tiebout's Pure Theory of Local Expenditures serves as a helpful framework in examining the emergence of the learning society, communications technologies, freer trade, and the effects these will have on the educational infrastructure. Tiebout argued that the failure of market-type systems of public good at the central government level does…

  18. Underground coal gasification using oxygen and steam

    SciTech Connect

    Yang, L.H.; Zhang, X.; Liu, S.

    2009-07-01

    In this paper, through model experiment of the underground coal gasification, the effects of pure oxygen gasification, oxygen-steam gasification, and moving-point gasification methods on the underground gasification process and gas quality were studied. Experiments showed that H{sub 2} and CO volume fraction in product gas during the pure oxygen gasification was 23.63-30.24% and 35.22-46.32%, respectively, with the gas heating value exceeding 11.00 MJ/m{sup 3}; under the oxygen-steam gasification, when the steam/oxygen ratio stood at 2: 1, gas compositions remained virtually stable and CO + H{sub 2} was basically between 61.66 and 71.29%. Moving-point gasification could effectively improve the changes in the cavity in the coal seams or the effects of roof inbreak on gas quality; the ratio of gas flowing quantity to oxygen supplying quantity was between 3.1:1 and 3.5:1 and took on the linear changes; on the basis of the test data, the reasons for gas quality changes under different gasification conditions were analyzed.

  19. Understanding Moisture and Carbon Dioxide Involved Interfacial Reactions on Electrochemical Performance of Lithium-Air Batteries Catalyzed by Gold/Manganese-Dioxide.

    PubMed

    Wang, Guoqing; Huang, Liliang; Liu, Shuangyu; Xie, Jian; Zhang, Shichao; Zhu, Peiyi; Cao, Gaoshao; Zhao, Xinbing

    2015-11-01

    Lithium-air (Li-air) battery works essentially based on the interfacial reaction of 2Li + O2 ↔ Li2O2 on the catalyst/oxygen-gas/electrolyte triphase interface. Operation of Li-air batteries in ambient air still remains a great challenge despite the recent development, because some side reactions related to moisture (H2O) and carbon dioxide (CO2) will occur on the interface with the formation of some inert byproducts on the surface of the catalyst. In this work, we investigated the effect of H2O and CO2 on the electrochemical performance of Li-air batteries to evaluate the practical operation of the batteries in ambient air. The use of a highly efficient gold/δ-manganese-dioxide (Au/δ-MnO2) catalyst helps to understand the intrinsic mechanism of the effect. We found that H2O has a more detrimental influence than CO2 on the battery performance when operated in ambient air. The battery operated in simulated dry air can sustain a stable cycling up to 200 cycles at 400 mA g(-1) with a relatively low polarization, which is comparable with that operated in pure O2. This work provides a possible method to operate Li-air batteries in ambient air by using optimized catalytic electrodes with a protective layer, for example a hydrophobic membrane. PMID:26466174

  20. Oxygen production using solid-state zirconia electrolyte technology

    NASA Technical Reports Server (NTRS)

    Suitor, Jerry W.; Clark, Douglas J.

    1991-01-01

    High purity oxygen is required for a number of scientific, medical, and industrial applications. Traditionally, these needs have been met by cryogenic distillation or pressure swing adsorption systems designed to separate oxygen from air. Oxygen separation from air via solid-state zirconia electrolyte technology offers an alternative to these methods. The technology has several advantages over the traditional methods, including reliability, compactness, quiet operation, high purity output, and low power consumption.

  1. [Is it necessary to humidify inhaled low-flow oxygen or low-concentration oxygen?].

    PubMed

    Miyamoto, Kenji

    2004-02-01

    In Japan, oxygen is routinely humidified in almost every hospital and clinic. In contrast, in Europe and North America, oxygen is not humidified as long as the oxygen flow is less than 4-5 L/min, according to the guidelines for oxygen therapy announced by the ACCP-NHLBI in 1984 and by AARC in 1992. In this paper, we demonstrate mathematically that: 1) the oxygen received through a nasal cannula at 0.5-4 L/min or through a Venturi mask at 24-40% constitutes only a small percentage of the patient's inspiratory tidal volume (2.4-19% and 3.8-24%, respectively), 2) the humidity deficit caused by inhaling unhumidified oxygen through a nasal cannula at 0.5-4 L/min or through a Venturi mask at 24% to 31% is very small compared with the water content delivered from the airway, and 3) this humidity deficit is easily compensated for by increasing the relative humidity of the room air a little, e.g., by only 4% in case of inhalation of 2 L/min of oxygen through a nasal cannula. Similar results are obtained when a Venturi mask is used to inhale oxygen. From these calculations, we conclude that routine humidification of low-flow oxygen or low-concentration oxygen is not justifiable in patients who need oxygen inhalation, as the humidity of room air is sufficient. PMID:15007913

  2. Effect of cation structure on the oxygen solubility and diffusivity in a range of bis{(trifluoromethyl)sulfonyl}imide anion based ionic liquids for lithium-air battery electrolytes.

    PubMed

    Neale, Alex R; Li, Peilin; Jacquemin, Johan; Goodrich, Peter; Ball, Sarah C; Compton, Richard G; Hardacre, Christopher

    2016-04-28

    This paper reports on the solubility and diffusivity of dissolved oxygen in a series of ionic liquids (ILs) based on the bis{(trifluoromethyl)sulfonyl}imide anion with a range of related alkyl and ether functionalised cyclic alkylammonium cations. Cyclic voltammetry has been used to observe the reduction of oxygen in ILs at a microdisk electrode and chronoamperometric measurements have then been applied to simultaneously determine both the concentration and the diffusion coefficient of oxygen in different ILs. The viscosity of the ILs and the calculated molar volume and free volume are also reported. It is found that, within this class of ILs, the oxygen diffusivity generally increases with decreasing viscosity of the neat IL. An inverse relationship between oxygen solubility and IL free volume is reported for the two IL families implying that oxygen is not simply occupying the available empty space. In addition, it is reported that the introduction of an ether-group into the IL cation structure promotes the diffusivity of dissolved oxygen but reduces the solubility of the gas. PMID:27052672

  3. Ag-Cu nanoalloyed film as a high-performance cathode electrocatalytic material for zinc-air battery

    NASA Astrophysics Data System (ADS)

    Lei, Yimin; Chen, Fuyi; Jin, Yachao; Liu, Zongwen

    2015-04-01

    A novel Ag50Cu50 film electrocatalyst for oxygen reduction reaction (ORR) was prepared by pulsed laser deposition (PLD) method. The electrocatalyst actually is Ag-Cu alloyed nanoparticles embedded in amorphous Cu film, based on transmission electron microscopy (TEM) characterization. The rotating disk electrode (RDE) measurements provide evidence that the ORR proceed via a four-electron pathway on the electrocatalysts in alkaline solution. And it is much more efficient than pure Ag catalyst. The catalytic layer has maximum power density of 67 mW cm-2 and an acceptable cell voltage at 0.863 V when current densities increased up to 100 mA cm-2 in the Ag50Cu50-based primary zinc-air battery. The resulting rechargeable zinc-air battery exhibits low charge-discharge voltage polarization of 1.1 V at 20 mAcm-2 and high durability over 100 cycles in natural air.

  4. Lithium-Air Battery: High Performance Cathodes for Lithium-Air Batteries

    SciTech Connect

    2010-08-01

    BEEST Project: Researchers at Missouri S&T are developing an affordable lithium-air (Li-Air) battery that could enable an EV to travel up to 350 miles on a single charge. Today’s EVs run on Li-Ion batteries, which are expensive and suffer from low energy density compared with gasoline. This new Li-Air battery could perform as well as gasoline and store 3 times more energy than current Li-Ion batteries. A Li-Air battery uses an air cathode to breathe oxygen into the battery from the surrounding air, like a human lung. The oxygen and lithium react in the battery to produce electricity. Current Li-Air batteries are limited by the rate at which they can draw oxygen from the air. The team is designing a battery using hierarchical electrode structures to enhance air breathing and effective catalysts to accelerate electricity production.

  5. The Termite Gut Microflora as an Oxygen Sink: Microelectrode Determination of Oxygen and pH Gradients in Guts of Lower and Higher Termites

    PubMed Central

    Brune, A.; Emerson, D.; Breznak, J. A.

    1995-01-01

    Clark-type oxygen microelectrodes and glass pH microelectrodes, each with a tip diameter of <=10 (mu)m, were used to obtain high-resolution profiles of oxygen concentrations and pH values in isolated termite guts. Radial oxygen profiles showed that oxygen penetrated into the peripheral hindgut contents up to about 150 to 200 (mu)m below the epithelial surface in both the lower termite Reticulitermes flavipes (Kollar) and the higher termite Nasutitermes lujae (Wasmann). Only the central portions (comprising less than 40% of the total volume) of the microbe-packed, enlarged hindgut compartments ("paunches") were completely anoxic, indicating that some members of the hindgut microbiota constitute a significant oxygen sink. From the slopes of the oxygen gradients, we estimated that the entire paunches (gut tissue plus resident microbiota) of R. flavipes and N. lujae accounted for 21 and 13%, respectively, of the respiratory activity of the intact animals. Axial oxygen profiles also confirmed that in general, only the paunches were anoxic in their centers, whereas midguts and posterior hindgut regions contained significant amounts of oxygen (up to about 50 and 30% air saturation, respectively). A remarkable exception to this was the posterior portion of an anterior segment (the P1 segment) of the hindgut of N. lujae, which was completely anoxic despite its small diameter ((apprx=)250 (mu)m). Axial pH profiles of the guts of Nasutitermes nigriceps (Haldeman) and Microcerotermes parvus (Haviland) revealed that there were extreme shifts as we moved posteriorly from the midgut proper (pH (apprx=)7) to the P1 segment of the hindgut (pH >10) and then to the P3 segment (paunch; pH (apprx=)7). The latter transition occurred at the short enteric valve (P2 segment) and within a distance of less than 500 (mu)m. In contrast, R. flavipes, which lacks a readily distinguishable P1 segment, did not possess a markedly alkaline region, and the pH around the midgut-hindgut junction was

  6. Solid-State Compressor for Space Station Oxygen Recovery

    NASA Technical Reports Server (NTRS)

    Finn, John E.

    2002-01-01

    At present, the life support system on the International Space Station Alpha vents overboard the carbon dioxide (CO2) produced by the crew members. Recovering the oxygen contained in the CO2 has the potential to reduce resupply mass by 2000 pounds per year or more, a significant weight that could be used for experimental payloads and other valuable items. The technologies used to remove CO2 from the air and to recover O2 from CO2 are flight-ready; however, the interface between the devices is a problem for the Space Station system. Ames Research Center has developed a new technology that solves the interface issue, possibly allowing closure of the oxygen loop in a spacecraft for the first time. CO2 produced by the crew is removed in the Carbon Dioxide Removal Assembly (CDRA). This device effectively produces a pure CO2 stream, but at a very low pressure. Elsewhere, the oxygen generation system which makes O2 by electrolyzing water produces a hydrogen stream. In principle the CO2 and H2 can react to form methane and water over a suitable catalyst. Water produced in this methane-formation reactor can be returned to the water electrolyzer, where the O2 can be returned to the cabin; however, the methane-formation reactor requires CO2 at a much higher pressure than that produced by the CDRA. Furthermore, the CO2 and H2 are often not available at the same time, due to power management and scheduling on the space station. In order to get the CO2 to the reactor at the right pressure and at the right time, a device or assembly that functions as a vacuum pump, compressor, and storage tank is required.

  7. Device and method for separating oxygen isotopes

    DOEpatents

    Rockwood, Stephen D.; Sander, Robert K.

    1984-01-01

    A device and method for separating oxygen isotopes with an ArF laser which produces coherent radiation at approximately 193 nm. The output of the ArF laser is filtered in natural air and applied to an irradiation cell where it preferentially photodissociates molecules of oxygen gas containing .sup.17 O or .sup.18 O oxygen nuclides. A scavenger such as O.sub.2, CO or ethylene is used to collect the preferentially dissociated oxygen atoms and recycled to produce isotopically enriched molecular oxygen gas. Other embodiments utilize an ArF laser which is narrowly tuned with a prism or diffraction grating to preferentially photodissociate desired isotopes. Similarly, desired mixtures of isotopic gas can be used as a filter to photodissociate enriched preselected isotopes of oxygen.

  8. A Survey of Alternative Oxygen Production Technologies

    NASA Technical Reports Server (NTRS)

    Lueck, Dale E.; Parrish, Clyde F.; Buttner, William J.; Surma, Jan M.; Delgado, H. (Technical Monitor)

    2000-01-01

    Utilization of the Martian atmosphere for the production of fuel and oxygen has been extensively studied. The baseline fuel production process is a Sabatier reactor, which produces methane and water from carbon dioxide and hydrogen. The oxygen produced from the electrolysis of the water is only half of that needed for methane-based rocket propellant, and additional oxygen is needed for breathing air, fuel cells and other energy sources. Zirconia electrolysis cells for the direct reduction of CO2 are being developed as an alternative means of producing oxygen, but present many challenges for a large-scale oxygen production system. The very high operating temperatures and fragile nature of the cells coupled with fairly high operating voltages leave room for improvement. This paper will survey alternative oxygen production technologies, present data on operating characteristics, materials of construction, and some preliminary laboratory results on attempts to implement each.

  9. Pure field theories and MACSYMA algorithms

    NASA Technical Reports Server (NTRS)

    Ament, W. S.

    1977-01-01

    A pure field theory attempts to describe physical phenomena through singularity-free solutions of field equations resulting from an action principle. The physics goes into forming the action principle and interpreting specific results. Algorithms for the intervening mathematical steps are sketched. Vacuum general relativity is a pure field theory, serving as model and providing checks for generalizations. The fields of general relativity are the 10 components of a symmetric Riemannian metric tensor; those of the Einstein-Straus generalization are the 16 components of a nonsymmetric. Algebraic properties are exploited in top level MACSYMA commands toward performing some of the algorithms of that generalization. The light cone for the theory as left by Einstein and Straus is found and simplifications of that theory are discussed.

  10. Effective pure states for bulk quantum computation

    SciTech Connect

    Knill, E.; Chuang, I.; Laflamme, R.

    1997-11-01

    In bulk quantum computation one can manipulate a large number of indistinguishable quantum computers by parallel unitary operations and measure expectation values of certain observables with limited sensitivity. The initial state of each computer in the ensemble is known but not pure. Methods for obtaining effective pure input states by a series of manipulations have been described by Gershenfeld and Chuang (logical labeling) and Corey et al. (spatial averaging) for the case of quantum computation with nuclear magnetic resonance. We give a different technique called temporal averaging. This method is based on classical randomization, requires no ancilla qubits and can be implemented in nuclear magnetic resonance without using gradient fields. We introduce several temporal averaging algorithms suitable for both high temperature and low temperature bulk quantum computing and analyze the signal to noise behavior of each.

  11. Black Hole Attractors and Pure Spinors

    SciTech Connect

    Hsu, Jonathan P.; Maloney, Alexander; Tomasiello, Alessandro

    2006-02-21

    We construct black hole attractor solutions for a wide class of N = 2 compactifications. The analysis is carried out in ten dimensions and makes crucial use of pure spinor techniques. This formalism can accommodate non-Kaehler manifolds as well as compactifications with flux, in addition to the usual Calabi-Yau case. At the attractor point, the charges fix the moduli according to {Sigma}f{sub k} = Im(C{Phi}), where {Phi} is a pure spinor of odd (even) chirality in IIB (A). For IIB on a Calabi-Yau, {Phi} = {Omega} and the equation reduces to the usual one. Methods in generalized complex geometry can be used to study solutions to the attractor equation.

  12. Computing Properties Of Pure And Mixed Fluids

    NASA Technical Reports Server (NTRS)

    Fowler, J. R.; Hendricks, Robert C.

    1993-01-01

    GASPLUS created as two-part code: first designed for use with pure fluids and second designed for use with mixtures of fluids and phases. Offers routines for mathematical modeling of conditions of fluids in pumps, turbines, compressors and other machines. Other routines for calculating performance of para/ortho-hydrogen reactor and heat of para/normal-hydrogen reaction as well as unique convergence routine demonstrates engineering flavor of GASPLUS. Written in FORTRAN 77.

  13. Guide for Oxygen Hazards Analyses on Components and Systems

    NASA Technical Reports Server (NTRS)

    Stoltzfus, Joel M.; Dees, Jesse; Poe, Robert F.

    1996-01-01

    Because most materials, including metals, will burn in an oxygen-enriched environment, hazards are always present when using oxygen. Most materials will ignite at lower temperatures in an oxygen-enriched environment than in air, and once ignited, combustion rates are greater in the oxygen-enriched environment. Many metals burn violently in an oxygen-enriched environment when ignited. Lubricants, tapes, gaskets, fuels, and solvents can increase the possibility of ignition in oxygen systems. However, these hazards do not preclude the use of oxygen. Oxygen may be safely used if all the materials in a system are not flammable in the end-use environment or if ignition sources are identified and controlled. These ignition and combustion hazards necessitate a proper oxygen hazards analysis before introducing a material or component into oxygen service. The objective of this test plan is to describe the White Sands Test Facility oxygen hazards analysis to be performed on components and systems before oxygen is introduced and is recommended before implementing the oxygen component qualification procedure. The plan describes the NASA Johnson Space Center White Sands Test Facility method consistent with the ASTM documents for analyzing the hazards of components and systems exposed to an oxygen-enriched environment. The oxygen hazards analysis is a useful tool for oxygen-system designers, system engineers, and facility managers. Problem areas can be pinpointed before oxygen is introduced into the system, preventing damage to hardware and possible injury or loss of life.

  14. Detection of molecular oxygen on Mars.

    NASA Technical Reports Server (NTRS)

    Carleton, N. P.; Traub, W. A.

    1972-01-01

    Molecular oxygen was detected in Martian spectra near 7635 A and its abundance was measured both during and after the 1971 dust storm. Its column abundance in the clear Martian atmosphere is about 10.4 plus or minus 1.0 cm/amagat, giving a mixing ratio of molecular oxygen to carbon dioxide 0.0013. The mixing ratio of molecular oxygen to carbon monoxide (1.4 plus or minus 0.3) is quite different from the value of 0.5 that would result from the photolysis of a pure carbon dioxide atmosphere, which indicates that there is or was a net source of oxygen relative to carbon (probably water) in the Martian atmosphere.

  15. Effective pure states for bulk quantum computation

    SciTech Connect

    Knill, E.; Chuang, I.; Laflamme, R.

    1998-05-01

    In bulk quantum computation one can manipulate a large number of indistinguishable quantum computers by parallel unitary operations and measure expectation values of certain observables with limited sensitivity. The initial state of each computer in the ensemble is known but not pure. Methods for obtaining effective pure input states by a series of manipulations have been described by Gershenfeld and Chuang (logical labeling) [Science {bold 275}, 350 (1997)] and Cory {ital et al.} (spatial averaging) [Proc. Natl. Acad. Sci. USA {bold 94}, 1634 (1997)] for the case of quantum computation with nuclear magnetic resonance. We give a different technique called temporal averaging. This method is based on classical randomization, requires no ancilla quantum bits, and can be implemented in nuclear magnetic resonance without using gradient fields. We introduce several temporal averaging algorithms suitable for both high-temperature and low-temperature bulk quantum computing and analyze the signal-to-noise behavior of each. Most of these algorithms require only a constant multiple of the number of experiments needed by the other methods for creating effective pure states. {copyright} {ital 1998} {ital The American Physical Society}

  16. On constructing purely affine theories with matter

    NASA Astrophysics Data System (ADS)

    Cervantes-Cota, Jorge L.; Liebscher, D.-E.

    2016-08-01

    We explore ways to obtain the very existence of a space-time metric from an action principle that does not refer to it a priori. Although there are reasons to believe that only a non-local theory can viably achieve this goal, we investigate here local theories that start with Schrödinger's purely affine theory (Schrödinger in Space-time structure. Cambridge UP, Cambridge, 1950), where he gave reasons to set the metric proportional to the Ricci curvature aposteriori. When we leave the context of unified field theory, and we couple the non-gravitational matter using some weak equivalence principle, we can show that the propagation of shock waves does not define a lightcone when the purely affine theory is local and avoids the explicit use of the Ricci tensor in realizing the weak equivalence principle. When the Ricci tensor is substituted for the metric, the equations seem to have only a very limited set of solutions. This backs the conviction that viable purely affine theories have to be non-local.

  17. Graphical calculus for Gaussian pure states

    SciTech Connect

    Menicucci, Nicolas C.; Flammia, Steven T.; Loock, Peter van

    2011-04-15

    We provide a unified graphical calculus for all Gaussian pure states, including graph transformation rules for all local and semilocal Gaussian unitary operations, as well as local quadrature measurements. We then use this graphical calculus to analyze continuous-variable (CV) cluster states, the essential resource for one-way quantum computing with CV systems. Current graphical approaches to CV cluster states are only valid in the unphysical limit of infinite squeezing, and the associated graph transformation rules only apply when the initial and final states are of this form. Our formalism applies to all Gaussian pure states and subsumes these rules in a natural way. In addition, the term 'CV graph state' currently has several inequivalent definitions in use. Using this formalism we provide a single unifying definition that encompasses all of them. We provide many examples of how the formalism may be used in the context of CV cluster states: defining the 'closest' CV cluster state to a given Gaussian pure state and quantifying the error in the approximation due to finite squeezing; analyzing the optimality of certain methods of generating CV cluster states; drawing connections between this graphical formalism and bosonic Hamiltonians with Gaussian ground states, including those useful for CV one-way quantum computing; and deriving a graphical measure of bipartite entanglement for certain classes of CV cluster states. We mention other possible applications of this formalism and conclude with a brief note on fault tolerance in CV one-way quantum computing.

  18. Composite oxygen transport membrane

    SciTech Connect

    Christie, Gervase Maxwell; Lane, Jonathan A.

    2014-08-05

    A method of producing a composite oxygen ion membrane and a composite oxygen ion membrane in which a porous fuel oxidation layer and a dense separation layer and optionally, a porous surface exchange layer are formed on a porous support from mixtures of (Ln.sub.1-xA.sub.x).sub.wCr.sub.1-yB.sub.yO.sub.3-.delta. and a doped zirconia. In the porous fuel oxidation layer and the optional porous surface exchange layer, A is Calcium and in the dense separation layer A is not Calcium and, preferably is Strontium. Preferred materials are (La.sub.0.8Ca.sub.0.2).sub.0.95Cr.sub.0.5Mn.sub.0.5O.sub.3-.delta. for the porous fuel oxidation and optional porous surface exchange layers and (La.sub.0.8Sr.sub.0.2).sub.0.95Cr.sub.0.5Fe.sub.0.5O.sub.3-.delta. for the dense separation layer. The use of such materials allows the membrane to sintered in air and without the use of pore formers to reduce membrane manufacturing costs. The use of materials, as described herein, for forming the porous layers have application for forming any type of porous structure, such as a catalyst support.

  19. Reflection on Teaching and Epistemological Structure: Reflective and Critically Reflective Processes in "Pure/Soft" and "Pure/Hard" Fields

    ERIC Educational Resources Information Center

    Kreber, Carolin; Castleden, Heather

    2009-01-01

    We empirically explored whether academics from pure/soft and pure/hard fields engage in reflective practice on teaching differently and, if so, whether these differences could be partially explained by the epistemological structure of their discipline. Interview data from academics in pure/hard (N = 30) and pure/soft fields (N = 10) were…

  20. Linear air-fuel sensor development

    SciTech Connect

    Garzon, F.; Miller, C.

    1996-12-14

    The electrochemical zirconia solid electrolyte oxygen sensor, is extensively used for monitoring oxygen concentrations in various fields. They are currently utilized in automobiles to monitor the exhaust gas composition and control the air-to-fuel ratio, thus reducing harmful emission components and improving fuel economy. Zirconia oxygen sensors, are divided into two classes of devices: (1) potentiometric or logarithmic air/fuel sensors; and (2) amperometric or linear air/fuel sensors. The potentiometric sensors are ideally suited to monitor the air-to-fuel ratio close to the complete combustion stoichiometry; a value of about 14.8 to 1 parts by volume. This occurs because the oxygen concentration changes by many orders of magnitude as the air/fuel ratio is varied through the stoichiometric value. However, the potentiometric sensor is not very sensitive to changes in oxygen partial pressure away from the stoichiometric point due to the logarithmic dependence of the output voltage signal on the oxygen partial pressure. It is often advantageous to operate gasoline power piston engines with excess combustion air; this improves fuel economy and reduces hydrocarbon emissions. To maintain stable combustion away from stoichiometry, and enable engines to operate in the excess oxygen (lean burn) region several limiting-current amperometric sensors have been reported. These sensors are based on the electrochemical oxygen ion pumping of a zirconia electrolyte. They typically show reproducible limiting current plateaus with an applied voltage caused by the gas diffusion overpotential at the cathode.

  1. Rhenium/Oxygen Interactions at Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Jacobson, Nathan; Myers, Dwight; Zhu, Dong-Ming; Humphrey, Donald

    2000-01-01

    The oxidation of pure rhenium is examined from 600-1400 C in oxygen/argon mixtures. Linear weight loss kinetics are observed. Gas pressures, flow rates, and temperatures are methodically varied to determine the rate controlling steps. The reaction at 600 and 800 C appears to be controlled by a chemical reaction step at the surface; whereas the higher temperature reactions appear to be controlled by gas phase diffusion of oxygen to the rhenium surface. Attack of the rhenium appears to be along grain boundaries and crystallographic planes.

  2. Oxygen inhalation using an oxygen concentrator in a low-pressure environment outside of a hospital.

    PubMed

    Sakaue, Hirokazu; Suto, Takashi; Kimura, Masafumi; Narahara, Sou; Sato, Tomonobu; Tobe, Masaru; Aso, Chizu; Kakinuma, Toshie; Hardy-Yamada, Makiko; Saito, Shigeru

    2008-11-01

    Supplementation with oxygen is fundamental in rescue and emergency medicine. However, transportation of oxygen cylinders or a rigid hyperbaric chamber requires large work forces. Also, oxygen in a cylinder may be completely consumed during a rescue action. The oxygen concentrators, which enrich the oxygen percentage of ambient air, may free rescuers from carrying heavy oxygen cylinders. In the present study, 2 types of oxygen concentrators were tested in a mountain hut located at an altitude of 3776 m. Oxygen concentration of the generated gas was 28.6% +/- 0.8% with the first machine, which was powered by an internal battery. Arterial oxygen saturation of the volunteers inhaling through the machine increased from the original 79% +/- 6% to 82% +/- 6%. When the machine was used with a semi-closed circuit, the value increased further to 90% +/- 3%. The second concentrator, which was powered by an external electric generator, outputted 90% +/- 2% oxygen. Arterial oxygen saturation of the volunteers increased to 95% +/- 1%. It is concluded that both types of oxygen concentrators were efficient at high altitude. PMID:19091263

  3. Lithium-Air Cell Development

    NASA Technical Reports Server (NTRS)

    Reid, Concha M.; Dobley, Arthur; Seymour, Frasier W.

    2014-01-01

    Lithium-air (Li-air) primary batteries have a theoretical specific capacity of 11,400 Wh/kg, the highest of any common metal-air system. NASA is developing Li-air technology for a Mobile Oxygen Concentrator for Spacecraft Emergencies, an application which requires an extremely lightweight primary battery that can discharge over 24 hours continuously. Several vendors were funded through the NASA SBIR program to develop Li-air technology to fulfill the requirements of this application. New catalysts and carbon cathode structures were developed to enhance the oxygen reduction reaction and increase surface area to improve cell performance. Techniques to stabilize the lithium metal anode surface were explored. Experimental results for prototype laboratory cells are given. Projections are made for the performance of hypothetical cells constructed from the materials that were developed.

  4. Living with Oxygen Therapy

    MedlinePlus

    ... page from the NHLBI on Twitter. Living With Oxygen Therapy Oxygen therapy helps many people function better and be ... chronic obstructive pulmonary disease) Although you may need oxygen therapy continuously or for long periods, it doesn' ...

  5. The influence of Kr, CO2, and iso-C4H8 admixtures on the time of the formation of a stable flame front in mixtures of natural gas and isobutylene with oxygen and hydrogen with air under initiation with a spark discharge

    NASA Astrophysics Data System (ADS)

    Rubtsov, N. M.; Seplyarskii, B. S.; Chernysh, V. I.; Tsvetkov, G. I.

    2010-05-01

    High-speed color filming was used to study laminar spherical flame propagation at the initial stage in preliminarily mixed stoichiometric mixtures of natural gas and isobutylene with oxygen containing krypton and carbon dioxide and in hydrogen-air mixtures at atmospheric pressure in a bomb with a constant volume. Under experimental conditions ( T 0 = 298 K, p 0 = 100 torr, spark discharge energy E 0 = 0.91 J), the dilution of mixtures with Kr and CO2 increased the time of formation of a stable flame front by more than 10 times. The introduction of a small chemically active admixture (1.2% isobutylene) into a stoichiometric mixture of hydrogen and air sharply increased the time of formation of a stable flame front, which was evidence of an important role played by the chemical mechanism of the reaction in the formation of the combustion field.

  6. Air Abrasion

    MedlinePlus

    ... delivered directly to your desktop! more... What Is Air Abrasion? Article Chapters What Is Air Abrasion? What Happens? The Pros and Cons Will I Feel Anything? Is Air Abrasion for Everyone? print full article print this ...

  7. Absorption process for producing oxygen and nitrogen and solution therefor

    DOEpatents

    Roman, I.C.; Baker, R.W.

    1990-09-25

    Process for the separation and purification of oxygen and nitrogen is disclosed which utilizes solutions of oxygen carriers to selectively absorb oxygen from a gaseous stream, leaving nitrogen as a byproduct. In the process, an oxygen carrier capable of reversibly binding molecular oxygen is dissolved in a solvent solution, which absorbs oxygen from an oxygen-containing gaseous feed stream such as atmospheric air and desorbs oxygen to a gaseous product stream. The feed stream is maintained at a sufficiently high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, while the product stream is maintained at a sufficiently low oxygen pressure to keep the carrier in its deoxygenated form during desorption. In an alternate mode of operation, the carrier solution is maintained at a sufficiently low temperature and high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, and at a sufficiently high temperature to keep the carrier in its deoxygenated form during desorption. Under such conditions, exceptionally high oxygen concentrations on the order of 95% to 99% are obtained, as well as a long carrier lifetime in excess of 3 months, making the process commercially feasible. 1 figure

  8. Absorption process for producing oxygen and nitrogen and solution therefor

    DOEpatents

    Roman, Ian C.

    1984-01-01

    Process for the separation and purification of oxygen and nitrogen is disclosed which utilizes solutions of oxygen carriers to selectively absorb oxygen from a gaseous stream, leaving nitrogen as a byproduct. In the process, an oxygen carrier capable of reversibly binding molecular oxygen is dissolved in a solvent solution, which absorbs oxygen from an oxygen-containing gaseous feed stream such as atmospheric air and desorbs oxygen to a gaseous product stream. The feed stream is maintained at a sufficiently high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, while the product stream is maintained at a sufficiently low oxygen pressure to keep the carrier in its deoxygenated form during desorption. In an alternate mode of operation, the carrier solution is maintained at a sufficiently low temperature and high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, and at a sufficiently high temperature to keep the carrier in its deoxygenated form during desorption. Under such conditions, exceptionally high oxygen concentrations on the order of 95% to 99% are obtained, as well as a long carrier lifetime in excess of 3 months, making the process commercially feasible.

  9. Absorption process for producing oxygen and nitrogen and solution therefor

    DOEpatents

    Roman, Ian C.; Baker, Richard W.

    1990-09-25

    Process for the separation and purification of oxygen and nitrogen is disclosed which utilizes solutions of oxygen carriers to selectively absorb oxygen from a gaseous stream, leaving nitrogen as a byproduct. In the process, an oxygen carrier capable of reversibly binding molecular oxygen is dissolved in a solvent solution, which absorbs oxygen from an oxygen-containing gaseous feed stream such as atmospheric air and desorbs oxygen to a gaseous product stream. The feed stream is maintained at a sufficiently high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, while the product stream is maintained at a sufficiently low oxygen pressure to keep the carrier in its deoxygenated form during desorption. In an alternate mode of operation, the carrier solution is maintained at a sufficiently low temperature and high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, and at a sufficiently high temperature to keep the carrier in its deoxygenated form during desorption. Under such conditions, exceptionally high oxygen concentrations on the order of 95% to 99% are obtained, as well as a long carrier lifetime in excess of 3 months, making the process commercially feasible.

  10. chemf: A purely functional chemistry toolkit

    PubMed Central

    2012-01-01

    Background Although programming in a type-safe and referentially transparent style offers several advantages over working with mutable data structures and side effects, this style of programming has not seen much use in chemistry-related software. Since functional programming languages were designed with referential transparency in mind, these languages offer a lot of support when writing immutable data structures and side-effects free code. We therefore started implementing our own toolkit based on the above programming paradigms in a modern, versatile programming language. Results We present our initial results with functional programming in chemistry by first describing an immutable data structure for molecular graphs together with a couple of simple algorithms to calculate basic molecular properties before writing a complete SMILES parser in accordance with the OpenSMILES specification. Along the way we show how to deal with input validation, error handling, bulk operations, and parallelization in a purely functional way. At the end we also analyze and improve our algorithms and data structures in terms of performance and compare it to existing toolkits both object-oriented and purely functional. All code was written in Scala, a modern multi-paradigm programming language with a strong support for functional programming and a highly sophisticated type system. Conclusions We have successfully made the first important steps towards a purely functional chemistry toolkit. The data structures and algorithms presented in this article perform well while at the same time they can be safely used in parallelized applications, such as computer aided drug design experiments, without further adjustments. This stands in contrast to existing object-oriented toolkits where thread safety of data structures and algorithms is a deliberate design decision that can be hard to implement. Finally, the level of type-safety achieved by Scala highly increased the reliability of our code

  11. Air liquefaction and enrichment system propulsion in reusable launch vehicles

    SciTech Connect

    Bond, W.H.; Yi, A.C.

    1994-07-01

    A concept is shown for a fully reusable, Earth-to-orbit launch vehicle with horizontal takeoff and landing, employing an air-turborocket for low speed and a rocket for high-speed acceleration, both using liquid hydrogen for fuel. The turborocket employs a modified liquid air cycle to supply the oxidizer. The rocket uses 90% pure liquid oxygen as its oxidizer that is collected from the atmosphere, separated, and stored during operation of the turborocket from about Mach 2 to 5 or 6. The takeoff weight and the thrust required at takeoff are markedly reduced by collecting the rocket oxidizer in-flight. This article shows an approach and the corresponding technology needs for using air liquefaction and enrichment system propulsion in a single-stage-to-orbit (SSTO) vehicle. Reducing the trajectory altitude at the end of collection reduces the wing area and increases payload. The use of state-of-the-art materials, such as graphite polyimide, in a direct substitution for aluminum or aluminum-lithium alloy, is critical to meet the structure weight objective for SSTO. Configurations that utilize `waverider` aerodynamics show great promise to reduce the vehicle weight. 5 refs.

  12. Enhanced oxygen separation through robust freeze-cast bilayered dual-phase membranes.

    PubMed

    Gaudillere, Cyril; Garcia-Fayos, Julio; Balaguer, María; Serra, José M

    2014-09-01

    Dual-phase oxygen-permeable asymmetric membranes with enhanced oxygen permeation were prepared by combining freeze-casting, screen-printing, and constraint-sintering techniques. The membranes were evaluated under oxyfuel operating conditions. The prepared membranes are composed of an original ice-templated La(0.6)Sr(0.4)Co(0.2)Fe(0.8)O(3-δ) support with hierarchically oriented porosity and a top fully densified bilayered coating comprising a 10 μm-thick La(0.6)Sr(0.4)Co(0.2)Fe(0.8)O(3-δ) layer and a top protective 8 μm-thick layer made of an optimized NiFe2O4/Ce(0.8)Tb(0.2)O(2-δ) composite synthesized by the one-pot Pechini method. Preliminary analysis confirmed the thermochemical compatibility of the three involved phases at high temperature without any additional phase detected. This membrane exhibited a promising oxygen permeation value of 4.8 mL min(-1)  cm(-2) at 1000 °C upon using Ar and air as the sweep and feed gases, respectively. Mimicking oxyfuel operating conditions by switching argon to pure CO2 as a sweep gas at 1000 °C and air as feed enabled an oxygen flux value of 5.6 mL min(-1)  cm(-2) to be reached. Finally, under the same conditions and increasing the oxygen partial pressure to 0.1 MPa in the feed, the oxygen permeation reached 12 mL min(-1)  cm(-2). The influence of CO2 content in the sweep gas was studied and its reversible and positive effect over oxygen permeation at temperatures equal to or above 950 °C was revealed. Finally, the membrane stability over a period of 150 h under CO2-rich sweep gas showed a low degradation rate of 2.4×10(-2)  mL min(-1)  cm(-2) per day. PMID:25070608

  13. Hydroxyl X2Pi pure rotational transitions

    NASA Technical Reports Server (NTRS)

    Goorvitch, D.; Goldman, A.; Dothe, Hoang; Tipping, R. H.; Chackerian, C., Jr.

    1992-01-01

    We present a list of frequencies, term values, Einstein A values, and assignments for the pure rotational transitions of the X2Pi state of the OH molecule. This list includes transitions from 3 to 2015/cm for Delta-v = 0, v-double-prime = 0-4, and J-double-prime = 0.5-49.5. The A values were computed using recent advances in calculating wave functions for a coupled system and an experimentally derived electric dipole moment function (Nelson et al., 1990) which exhibits curvature.

  14. Critical speeding up in pure fluids

    NASA Technical Reports Server (NTRS)

    Boukari, Hacene; Shaumeyer, J. N.; Briggs, Matthew E.; Gammon, Robert W.

    1990-01-01

    The extreme compressibility of a pure fluid near its critical point significantly affects its bulk dynamic response to temperature changes through adiabatic processes. Equations that describe the dynamics in the absence of gravity are developed, and the magnitude of the effect is illustrated with numerical solutions in one dimension. The results are remarkable: 5 mm of critical xenon, quenched from 20 to 10 mK above its critical temperature, cools by over 99 percent in less than 5 s. Moreover, adiabatic cooling is faster when the fluid is closer to the critical point.

  15. Pure type I supergravity and DE 10

    NASA Astrophysics Data System (ADS)

    Hillmann, Christian; Kleinschmidt, Axel

    2006-12-01

    We establish a dynamical equivalence between the bosonic part of pure type I supergravity in D = 10 and a D = 1 non-linear σ-model on the Kac Moody coset space DE 10/K(DE 10) if both theories are suitably truncated. To this end we make use of a decomposition of DE 10 under its regular SO(9,9) subgroup. Our analysis also deals partly with the fermionic fields of the supergravity theory and we define corresponding representations of the generalised spatial Lorentz group K(DE 10).

  16. Cold-Sprayed Nanostructured Pure Cobalt Coatings

    NASA Astrophysics Data System (ADS)

    Cavaliere, P.; Perrone, A.; Silvello, A.

    2016-08-01

    Cold-sprayed pure cobalt coatings were deposited on carbon-steel substrate. Submicrometer particles for spraying were produced via cryomilling. Deposits were produced using different processing conditions (gas temperature and pressure, nozzle-to-substrate distance) to evaluate the resulting variations in grain size dimension, microhardness, adhesion strength, and porosity. The coating mechanical properties improved greatly with higher temperature and carrying-gas pressure. The coating microstructure was analyzed as a function of spraying condition by transmission electron microscopy (TEM) observations, revealing many different microstructural features for coatings experiencing low or high strain rates during deposition.

  17. Pure seminoma: a review and update.

    PubMed

    Boujelbene, Noureddine; Cosinschi, Adrien; Boujelbene, Nadia; Khanfir, Kaouthar; Bhagwati, Shushila; Herrmann, Eveleyn; Mirimanoff, Rene-Olivier; Ozsahin, Mahmut; Zouhair, Abderrahim

    2011-01-01

    Pure seminoma is a rare pathology of the young adult, often discovered in the early stages. Its prognosis is generally excellent and many therapeutic options are available, especially in stage I tumors. High cure rates can be achieved in several ways: standard treatment with radiotherapy is challenged by surveillance and chemotherapy. Toxicity issues and the patients' preferences should be considered when management decisions are made. This paper describes firstly the management of primary seminoma and its nodal involvement and, secondly, the various therapeutic options according to stage. PMID:21819630

  18. Pure seminoma: A review and update

    PubMed Central

    2011-01-01

    Pure seminoma is a rare pathology of the young adult, often discovered in the early stages. Its prognosis is generally excellent and many therapeutic options are available, especially in stage I tumors. High cure rates can be achieved in several ways: standard treatment with radiotherapy is challenged by surveillance and chemotherapy. Toxicity issues and the patients' preferences should be considered when management decisions are made. This paper describes firstly the management of primary seminoma and its nodal involvement and, secondly, the various therapeutic options according to stage. PMID:21819630

  19. Are all maximally entangled states pure?

    NASA Astrophysics Data System (ADS)

    Cavalcanti, D.; Brandão, F. G. S. L.; Terra Cunha, M. O.

    2005-10-01

    We study if all maximally entangled states are pure through several entanglement monotones. In the bipartite case, we find that the same conditions which lead to the uniqueness of the entropy of entanglement as a measure of entanglement exclude the existence of maximally mixed entangled states. In the multipartite scenario, our conclusions allow us to generalize the idea of the monogamy of entanglement: we establish the polygamy of entanglement, expressing that if a general state is maximally entangled with respect to some kind of multipartite entanglement, then it is necessarily factorized of any other system.

  20. Are all maximally entangled states pure?

    SciTech Connect

    Cavalcanti, D.; Brandao, F.G.S.L.; Terra Cunha, M.O.

    2005-10-15

    We study if all maximally entangled states are pure through several entanglement monotones. In the bipartite case, we find that the same conditions which lead to the uniqueness of the entropy of entanglement as a measure of entanglement exclude the existence of maximally mixed entangled states. In the multipartite scenario, our conclusions allow us to generalize the idea of the monogamy of entanglement: we establish the polygamy of entanglement, expressing that if a general state is maximally entangled with respect to some kind of multipartite entanglement, then it is necessarily factorized of any other system.