Science.gov

Sample records for 111-lavatory oxygen systems

  1. 14 CFR 121.1500 - SFAR No. 111-Lavatory Oxygen Systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false SFAR No. 111-Lavatory Oxygen Systems. 121... § 121.1500 SFAR No. 111—Lavatory Oxygen Systems. (a) Applicability. This SFAR applies to the following... disabled lavatory oxygen systems, modified in accordance with FAA Airworthiness Directive...

  2. 14 CFR 21.700 - SFAR No. 111-Lavatory Oxygen Systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false SFAR No. 111-Lavatory Oxygen Systems. 21.700 Section 21.700 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... No. 111—Lavatory Oxygen Systems. The requirements of § 121.1500 of this chapter also apply to...

  3. 14 CFR 129.201 - SFAR No. 111-Lavatory Oxygen Systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false SFAR No. 111-Lavatory Oxygen Systems. 129.201 Section 129.201 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Special Federal Aviation Regulations § 129.201 SFAR No. 111—Lavatory Oxygen Systems. The requirements...

  4. 14 CFR 129.201 - SFAR No. 111-Lavatory Oxygen Systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false SFAR No. 111-Lavatory Oxygen Systems. 129.201 Section 129.201 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Special Federal Aviation Regulations § 129.201 SFAR No. 111—Lavatory Oxygen Systems. The requirements...

  5. 14 CFR 129.201 - SFAR No. 111-Lavatory Oxygen Systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false SFAR No. 111-Lavatory Oxygen Systems. 129.201 Section 129.201 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Special Federal Aviation Regulations § 129.201 SFAR No. 111—Lavatory Oxygen Systems. The requirements...

  6. 14 CFR 25.1801 - SFAR No. 111-Lavatory Oxygen Systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false SFAR No. 111-Lavatory Oxygen Systems. 25.1801 Section 25.1801 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Regulations § 25.1801 SFAR No. 111—Lavatory Oxygen Systems. The requirements of § 121.1500 of this...

  7. 14 CFR 21.700 - SFAR No. 111-Lavatory Oxygen Systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false SFAR No. 111-Lavatory Oxygen Systems. 21.700 Section 21.700 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... No. 111—Lavatory Oxygen Systems. The requirements of § 121.1500 of this chapter also apply to...

  8. 14 CFR 121.1500 - SFAR No. 111-Lavatory Oxygen Systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false SFAR No. 111-Lavatory Oxygen Systems. 121... § 121.1500 SFAR No. 111—Lavatory Oxygen Systems. (a) Applicability. This SFAR applies to the following persons: (1) All operators of transport category airplanes that are equipped with any chemical...

  9. 14 CFR 25.1801 - SFAR No. 111-Lavatory Oxygen Systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false SFAR No. 111-Lavatory Oxygen Systems. 25.1801 Section 25.1801 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Regulations § 25.1801 SFAR No. 111—Lavatory Oxygen Systems. The requirements of § 121.1500 of this...

  10. 14 CFR 21.700 - SFAR No. 111-Lavatory Oxygen Systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false SFAR No. 111-Lavatory Oxygen Systems. 21.700 Section 21.700 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... No. 111—Lavatory Oxygen Systems. The requirements of § 121.1500 of this chapter also apply to...

  11. 14 CFR 121.1500 - SFAR No. 111-Lavatory Oxygen Systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false SFAR No. 111-Lavatory Oxygen Systems. 121... § 121.1500 SFAR No. 111—Lavatory Oxygen Systems. (a) Applicability. This SFAR applies to the following persons: (1) All operators of transport category airplanes that are equipped with any chemical...

  12. 14 CFR 25.1801 - SFAR No. 111-Lavatory Oxygen Systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false SFAR No. 111-Lavatory Oxygen Systems. 25.1801 Section 25.1801 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Regulations § 25.1801 SFAR No. 111—Lavatory Oxygen Systems. The requirements of § 121.1500 of this...

  13. 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.

  14. 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.

  15. Glovebox oxygen monitoring system

    SciTech Connect

    Haggard, R.

    1993-08-01

    This system is located in the Replacement Tritium Facility (RTF) at the Savannah River Site of the US Department of Energy. The basic system consists of an oxygen sensor module located inside the glovebox and a wall mounted panel located outside the glovebox that contains an electronics package that displays the oxygen level, displays alarms, and sends signals to a facility Distributed Control System (DCS). RTF is a new facility that will be used primarily to load and unload tritium reservoirs, and recycle the tritium for use in existing or new reservoirs. Tritium, an oderless, colorless, gas is a radioactive isotope of hydrogen that is used in modern thermonuclear weapons. Once on-line, RTF will replace other tritium facilities that have been in existence since the 1950`s. Since the entire process at RTF is contained in nitrogen blanketed gloveboxes and features have been provided to recapture fugitive tritium, environmental releases and worker exposure to tritium will be reduced compared to the old facilities.

  16. Tissue oxygen measurement system

    NASA Technical Reports Server (NTRS)

    Soller, Babs R. (Inventor)

    2004-01-01

    A device and method in accordance with the invention for determining the oxygen partial pressure (PO.sub.2) of a tissue by irradiating the tissue with optical radiation such that the light is emitted from the tissue, and by collecting the reflected or transmitted light from the tissue to form an optical spectrum. A spectral processor determines the PO.sub.2 level in tissue by processing this spectrum with a previously-constructed spectral calibration model. The tissue may, for example, be disposed underneath a covering tissue, such as skin, of a patient, and the tissue illuminated and light collected through the skin. Alternatively, direct tissue illumination and collection may be effected with a hand-held or endoscopic probe. A preferred system also determines pH from the same spectrum, and the processor may determine critical conditions and issue warnings based on parameter values.

  17. Advanced Oxygen Systems for Aircraft (Systemes d’Oxygene Avances)

    DTIC Science & Technology

    1996-04-01

    for enhancing aircrew performance at high sustained +GZ accelerations. Finally, increasing attention has been paid over the last two decades to the...comprehensive published review of the design and performance of Advanced Oxygen Systems. It has been written principally by present and past members... performance required of Advanced Oxygen Systems and with the design and assessment of the first and later generations of these systems. The monograph

  18. Hybrid Oxygen System

    DTIC Science & Technology

    1992-10-01

    otherwise in any manner construed, as licensing the holder or any other person or corporation ; or as conveying any rights or permission to manufacture, use...12 Modest Activity 2 12 24 Comnat ane G’s Average 5 32 64 Peak Activity (NATO) 10 50 Instantaneous Peak Flow N/A 150-20W_ Published oxygen flow rates

  19. Mars oxygen production system design

    NASA Technical Reports Server (NTRS)

    Cotton, Charles E.; Pillow, Linda K.; Perkinson, Robert C.; Brownlie, R. P.; Chwalowski, P.; Carmona, M. F.; Coopersmith, J. P.; Goff, J. C.; Harvey, L. L.; Kovacs, L. A.

    1989-01-01

    The design and construction phase is summarized of the Mars oxygen demonstration project. The basic hardware required to produce oxygen from simulated Mars atmosphere was assembled and tested. Some design problems still remain with the sample collection and storage system. In addition, design and development of computer compatible data acquisition and control instrumentation is ongoing.

  20. Guide for Oxygen Compatibility Assessments on Oxygen Components and Systems

    NASA Technical Reports Server (NTRS)

    Rosales, Keisa R.; Shoffstall, Michael S.; Stoltzfus, Joel M.

    2007-01-01

    Understanding and preventing fire hazards is necessary when designing, maintaining, and operating oxygen systems. Ignition risks can be minimized by controlling heat sources and using materials that will not ignite or will not support burning in the end-use environment. Because certain materials are more susceptible to ignition in oxygen-enriched environments, a compatibility assessment should be performed before the component is introduced into an oxygen system. This document provides an overview of oxygen fire hazards and procedures that are consistent with the latest versions of American Society for Testing and Materials (ASTM) Standards G63 (1999) and G94 (2005) to address fire hazards associated with oxygen systems. This document supersedes the previous edition, NASA Technical Memorandum 104823, Guide for Oxygen Hazards Analyses on Components and Systems (1996). The step-by-step oxygen compatibility assessment method described herein (see Section 4) enables oxygen-system designers, system engineers, and facility managers to determine areas of concern with respect to oxygen compatibility and, ultimately, prevent damage to a system or injury to personnel.

  1. 76 FR 12550 - Lavatory Oxygen Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-08

    .... 21-94, 25-133, 121-354, and 129-50; SFAR 111] RIN 2120-AJ92 Lavatory Oxygen Systems AGENCY: Federal... temporarily authorizes variances from existing standards related to the provisioning of supplemental oxygen... oxygen systems inoperative. DATES: This interim rule is effective March 8, 2011 and remains in...

  2. Solid electrolyte oxygen regeneration system

    NASA Technical Reports Server (NTRS)

    Shumar, J. W.; See, G. G.; Schubert, F. H.; Powell, J. D.

    1976-01-01

    A program to design, develop, fabricate and assemble a one-man, self-contained, solid electrolyte oxygen regeneration system (SX-1) incorporating solid electrolyte electrolyzer drums was completed. The SX-1 is a preprototype engineering model designed to produce 0.952 kg (2.1 lb)/day of breathable oxygen (O2) from the electrolysis of metabolic carbon dioxide (CO2) and water vapor. The CO2 supply rate was established based on the metabolic CO2 generation rate for one man of 0.998 kg (2.2 lb)/day. The water supply rate (0.254 kg (0.56 lb)/day) was designed to be sufficient to make up the difference between the 0.952 kg (2.1 lb)/day O2 generation specification and the O2 available through CO2 electrolysis, 0.726 kg (1.6 lb)/day. The SX-1 was successfully designed, fabricated and assembled. Design verification tests (DVT) or the CO Disproportionators, H2 separators, control instrumentation, monitor instrumentation, water feed mechanism were successfully completed. The erratic occurrence of electrolyzer drum leakage prevented the completion of the CO2 electrolyzer module and water electrolyzer module DVT's and also prevented the performance of SX-1 integrated testing. Further development work is required to improve the solid electrolyte cell high temperature seals.

  3. 78 FR 5707 - Lavatory Oxygen Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-28

    ... Administration 14 CFR Part 121 RIN 2120-AK14 Lavatory Oxygen Systems AGENCY: Federal Aviation Administration (FAA... related to the provisioning of supplemental oxygen inside lavatories. This action is necessitated by the publication of Airworthiness Directive 2012-11-09, which mandates actions that restore supplemental oxygen...

  4. Boiler Control Systems Oxygen Trim Systems Manual.

    DTIC Science & Technology

    1983-02-01

    measurement , and how these measurements can be used to improve the boiler efficiency. Section 4.0 identifies the various combustion air trim systems that can...with the oxygen in air to form various gases, the formation of which results in the release of large amounts of heat referred to as the heat of...method of combustion optimization is just as effective. Carbon monoxide concentration is independent of excess air and is a direct measure of

  5. Solar Energy Systems for Lunar Oxygen Generation

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.; Heller, Richard S.; Wong, Wayne A.; Hepp, Aloysius F.

    2010-01-01

    An evaluation of several solar concentrator-based systems for producing oxygen from lunar regolith was performed. The systems utilize a solar concentrator mirror to provide thermal energy for the oxygen production process. Thermal energy to power a Stirling heat engine and photovoltaics are compared for the production of electricity. The electricity produced is utilized to operate the equipment needed in the oxygen production process. The initial oxygen production method utilized in the analysis is hydrogen reduction of ilmenite. Utilizing this method of oxygen production a baseline system design was produced. This baseline system had an oxygen production rate of 0.6 kg/hr with a concentrator mirror size of 5 m. Variations were performed on the baseline design to show how changes in the system size and process (rate) affected the oxygen production rate. An evaluation of the power requirements for a carbothermal lunar regolith reduction reactor has also been conducted. The reactor had a total power requirement between 8,320 to 9,961 W when producing 1000 kg/year of oxygen. The solar concentrator used to provide the thermal power (over 82 percent of the total energy requirement) would have a diameter of less than 4 m.

  6. Additively Manufactured Metals in Oxygen Systems Project

    NASA Technical Reports Server (NTRS)

    Tylka, Jonathan

    2015-01-01

    Metals produced by additive manufacturing methods, such as Powder Bed Fusion Technology, are now mature enough to be considered for qualification in human spaceflight oxygen systems. The mechanical properties of metals produced through AM processes are being systematically studied. However, it is unknown whether AM metals in oxygen applications may present an increased risk of flammability or ignition as compared to wrought metals of the same metallurgical composition due to increased porosity. Per NASA-STD-6001B materials to be used in oxygen system applications shall be based on flammability and combustion test data, followed by a flammability assessment. Without systematic flammability and ignition testing in oxygen there is no credible method for NASA to accurately evaluate the risk of using AM metals in oxygen systems.

  7. Safety Standard for Oxygen and Oxygen Systems: Guidelines for Oxygen System Design, Materials Selection, Operations, Storage, and Transportation

    NASA Technical Reports Server (NTRS)

    1996-01-01

    NASA's standard for oxygen system design, materials selection, operation, and transportation is presented. Minimum guidelines applicable to NASA Headquarters and all NASA Field Installations are contained.

  8. 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.

  9. Oxygen production System Models for Lunar ISRU

    NASA Technical Reports Server (NTRS)

    Santiago-Maldonado, Edgardo

    2007-01-01

    In-Situ Resource Utilization (ISRU) seeks to make human space exploration feasible; by using available resources from a planet or the moon to produce consumables, parts, and structures that otherwise would be brought from Earth. Producing these in situ reduces the mass of such that must be launched and doing so allows more payload mass' for each mission. The production of oxygen from lunar regolith, for life support and propellant, is one of the tasks being studied under ISRU. NASA is currently funding three processes that have shown technical merit for the production of oxygen from regolith: Molten Salt Electrolysis, Hydrogen Reduction of Ilmenite, and Carbothermal Reduction. The ISRU program is currently developing system models of, the , abovementioned processes to: (1) help NASA in the evaluation process to select the most cost-effective and efficient process for further prototype development, (2) identify key parameters, (3) optimize the oxygen production process, (4) provide estimates on energy and power requirements, mass and volume.of the system, oxygen production rate, mass of regolith required, mass of consumables, and other important parameters, and (5) integrate into the overall end-to-end ISRU system model, which could be integrated with mission architecture models. The oxygen production system model is divided into modules that represent unit operations (e.g., reactor, water electrolyzer, heat exchanger). Each module is modeled theoretically using Excel and Visual Basic for Applications (VBA), and will be validated using experimental data from on-going laboratory work. This modularity (plug-n-play) feature of each unit operation allows the use of the same model on different oxygen production systems simulations resulting in comparable results. In this presentation, preliminary results for mass, power, volume will be presented along with brief description of the oxygen production system model.

  10. Design guide for high pressure oxygen systems

    NASA Technical Reports Server (NTRS)

    Bond, A. C.; Pohl, H. O.; Chaffee, N. H.; Guy, W. W.; Allton, C. S.; Johnston, R. L.; Castner, W. L.; Stradling, J. S.

    1983-01-01

    A repository for critical and important detailed design data and information, hitherto unpublished, along with significant data on oxygen reactivity phenomena with metallic and nonmetallic materials in moderate to very high pressure environments is documented. This data and information provide a ready and easy to use reference for the guidance of designers of propulsion, power, and life support systems for use in space flight. The document is also applicable to designs for industrial and civilian uses of high pressure oxygen systems. The information presented herein are derived from data and design practices involving oxygen usage at pressures ranging from about 20 psia to 8000 psia equal with thermal conditions ranging from room temperatures up to 500 F.

  11. Cost analysis of oxygen recovery systems

    NASA Technical Reports Server (NTRS)

    Yakut, M. M.

    1973-01-01

    Report is made of the cost analysis of four leading oxygen recovery subsystems which include two carbon dioxide reduction subsystems and two water electrolysis subsystems, namely, the solid polymer electrolyte and the circulating KOH electrolyte. The four oxygen recovery systems were quantitatively evaluated. System characteristics, including process flows, performance, and physical characteristics were also analyzed. Additionally, the status of development of each of the systems considered and the required advance technology efforts required to bring conceptual and/or pre-prototype hardware to an operational prototype status were defined. Intimate knowledge of the operations, development status, and capabilities of the systems to meet space mission requirements were found to be essential in establishing the cost estimating relationships for advanced life support systems.

  12. Oxygen Compatibility Assessment of Components and Systems

    NASA Technical Reports Server (NTRS)

    Stoltzfus, Joel; Sparks, Kyle

    2010-01-01

    Fire hazards are inherent in oxygen systems and a storied history of fires in rocket engine propulsion components exists. To detect and mitigate these fire hazards requires careful, detailed, and thorough analyses applied during the design process. The oxygen compatibility assessment (OCA) process designed by NASA Johnson Space Center (JSC) White Sands Test Facility (WSTF) can be used to determine the presence of fire hazards in oxygen systems and the likelihood of a fire. This process may be used as both a design guide and during the approval process to ensure proper design features and material selection. The procedure for performing an OCA is a structured step-by-step process to determine the most severe operating conditions; assess the flammability of the system materials at the use conditions; evaluate the presence and efficacy of ignition mechanisms; assess the potential for a fire to breach the system; and determine the reaction effect (the potential loss of life, mission, and system functionality as the result of a fire). This process should be performed for each component in a system. The results of each component assessment, and the overall system assessment, should be recorded in a report that can be used in the short term to communicate hazards and their mitigation and to aid in system/component development and, in the long term, to solve anomalies that occur during engine testing and operation.

  13. U.S. Army Oxygen Generation System Development

    DTIC Science & Technology

    2010-04-01

    Electrochemical Oxygen Generation Oxygen can be produced electrochemically. Simple electrolysis of water produces oxygen at the anode and hydrogen at the...RTO-MP-HFM-182 18 - 1 1U.S. Army Oxygen Generation System Development Mark Arnold Oxygen System Products Manager Mark.Arnold...project in 1985 to develop the capability to generate oxygen at the point of use. Since 2001 the U.S. Army, in partnership with several vendors from

  14. 14 CFR 23.1445 - Oxygen distribution system.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Oxygen distribution system. 23.1445 Section... Equipment § 23.1445 Oxygen distribution system. (a) Except for flexible lines from oxygen outlets to the... used for any oxygen line that is normally pressurized during flight. (b) Nonmetallic...

  15. 14 CFR 23.1445 - Oxygen distribution system.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Oxygen distribution system. 23.1445 Section... Equipment § 23.1445 Oxygen distribution system. (a) Except for flexible lines from oxygen outlets to the... used for any oxygen line that is normally pressurized during flight. (b) Nonmetallic...

  16. 14 CFR 23.1445 - Oxygen distribution system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Oxygen distribution system. 23.1445 Section... Equipment § 23.1445 Oxygen distribution system. (a) Except for flexible lines from oxygen outlets to the... used for any oxygen line that is normally pressurized during flight. (b) Nonmetallic...

  17. 14 CFR 23.1445 - Oxygen distribution system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Oxygen distribution system. 23.1445 Section... Equipment § 23.1445 Oxygen distribution system. (a) Except for flexible lines from oxygen outlets to the... used for any oxygen line that is normally pressurized during flight. (b) Nonmetallic...

  18. Fires in P-3 Aircraft Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Stoltzfus, Joel

    2006-01-01

    Fires in three P3 aircraft oxygen systems have occurred: one in the Royal Australian Air Force (RAAF) in 1984 and two in the U.S. Navy in 1998 and 2003. All three fires started in the aluminum manifold and check valve (MCV) assembly and produced similar damages to the aircraft in which they occurred. This paper discusses a failure analysis conducted by the NASA Johnson Space Center White Sands Test Facility (WSTF) Oxygen Hazards and Testing Team on the 2003 U.S. Navy VP62 fire. It was surmised that the fire started due to heat generated by an oxygen leak past a silicone check valve seal or possibly because of particle impact near the seat of one of the MCV assembly check valves. An additional analysis of fires in several check valve poppet seals from other aircraft is discussed. These burned poppet seals came from P3 oxygen systems that had been serviced at the Naval Air Station (NAS) in Jacksonville following standard fill procedures. It was concluded that these seal fires occurred due to the heat from compression heating, particle impact, or the heat generated by an oxygen leak past the silicone check valve seal. The fact that catastrophic fires did not occur in the case of each check valve seal fire was attributed to the protective nature of the aluminum oxide layer on the check valve poppets. To prevent future fires of this nature, the U.S. and Canadian fleets of P3 aircraft have been retrofitted with MCV assemblies with an upgraded design and more burn-resistant materials.

  19. Imaging of oxygen in microreactors and microfluidic systems

    NASA Astrophysics Data System (ADS)

    Sun, Shiwen; Ungerböck, Birgit; Mayr, Torsten

    2015-09-01

    This review gives an overview on the state-of-the-art of oxygen imaging in microfluidics. Oxygen imaging using optical oxygen sensors based on luminescence is a versatile and powerful tool for obtaining profoundly space-resolved information of oxygen in microreactors and microfluidic systems. We briefly introduce the principle of oxygen imaging and present techniques of oxygen imaging applied in microreactors and microfluidic devices, including selection criteria and demands of sensing material and basic set-up for a 2D oxygen sensing system. A detailed review of oxygen imaging in microreactors and microfluidic systems is given on different applications in oxygen gradient monitoring, cell culturing, single-cell analysis and chemical reactions. Finally, we discuss challenges and trends of oxygen imaging in microfluidic systems.

  20. Spatially monitoring oxygen level in 3D microfabricated cell culture systems using optical oxygen sensing beads.

    PubMed

    Wang, Lin; Acosta, Miguel A; Leach, Jennie B; Carrier, Rebecca L

    2013-04-21

    Capability of measuring and monitoring local oxygen concentration at the single cell level (tens of microns scale) is often desirable but difficult to achieve in cell culture. In this study, biocompatible oxygen sensing beads were prepared and tested for their potential for real-time monitoring and mapping of local oxygen concentration in 3D micro-patterned cell culture systems. Each oxygen sensing bead is composed of a silica core loaded with both an oxygen sensitive Ru(Ph2phen3)Cl2 dye and oxygen insensitive Nile blue reference dye, and a poly-dimethylsiloxane (PDMS) shell rendering biocompatibility. Human intestinal epithelial Caco-2 cells were cultivated on a series of PDMS and type I collagen based substrates patterned with micro-well arrays for 3 or 7 days, and then brought into contact with oxygen sensing beads. Using an image analysis algorithm to convert florescence intensity of beads to partial oxygen pressure in the culture system, tens of microns-size oxygen sensing beads enabled the spatial measurement of local oxygen concentration in the microfabricated system. Results generally indicated lower oxygen level inside wells than on top of wells, and local oxygen level dependence on structural features of cell culture surfaces. Interestingly, chemical composition of cell culture substrates also appeared to affect oxygen level, with type-I collagen based cell culture systems having lower oxygen concentration compared to PDMS based cell culture systems. In general, results suggest that oxygen sensing beads can be utilized to achieve real-time and local monitoring of micro-environment oxygen level in 3D microfabricated cell culture systems.

  1. Oxygen Transfer Characteristics of Miniaturized Bioreactor Systems

    PubMed Central

    Kirk, Timothy V; Szita, Nicolas

    2013-01-01

    Since their introduction in 2001 miniaturized bioreactor systems have made great advances in function and performance. In this article the dissolved oxygen (DO) transfer performance of submilliliter microbioreactors, and 1–10 mL minibioreactors was examined. Microbioreactors have reached kLa values of 460 h-1, and are offering instrumentation and some functionality comparable to production systems, but at high throughput screening volumes. Minibioreactors, aside from one 1,440 h-1 kLa system, have not offered as high rates of DO transfer, but have demonstrated superior integration with automated fluid handling systems. Microbioreactors have been typically limited to studies with E. coli, while minibioreactors have offered greater versatility in this regard. Further, mathematical relationships confirming the applicability of kLa measurements across all scales have been derived, and alternatives to fluorescence lifetime DO sensors have been evaluated. Finally, the influence on reactor performance of oxygen uptake rate (OUR), and the possibility of its real-time measurement have been explored. Biotechnol. Bioeng. 2013; 110: 1005–1019. © 2012 Wiley Periodicals, Inc. PMID:23280578

  2. Environmental Control and Life Support System, Oxygen Generation System

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Environmental Control and Life Support System (ECLSS) Group of the Flight Projects Directorate at the Marshall Space Flight Center (MSFC) in Huntsville, Alabama, is responsible for designing and building the life support systems that will provide the crew of the International Space Station (ISS) a comfortable environment in which to live and work. This is a close-up view of ECLSS Oxygen Generation System (OGS) rack. The ECLSS Group at the MSFC oversees the development of the OGS, which produces oxygen for breathing air for the crew and laboratory animals, as well as for replacing oxygen lost due to experiment use, airlock depressurization, module leakage, and carbon dioxide venting. The OGS consists primarily of the Oxygen Generator Assembly (OGA), provided by the prime contractor, the Hamilton Sundstrand Space Systems, International (HSSSI) in Windsor Locks, Cornecticut and a Power Supply Module (PSM), supplied by the MSFC. The OGA is comprised of a cell stack that electrolyzes (breaks apart the hydrogen and oxygen molecules) some of the clean water provided by the Water Recovery System and the separators that remove the gases from water after electrolysis. The PSM provides the high power to the OGA needed to electrolyze the water.

  3. 14 CFR 23.1445 - Oxygen distribution system.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Oxygen distribution system. 23.1445 Section... Equipment § 23.1445 Oxygen distribution system. Link to an amendment published at 76 FR 75762, December 2, 2011. (a) Except for flexible lines from oxygen outlets to the dispensing units, or where shown to...

  4. ASRDI Oxygen Technological Survey. Volume 9; Oxygen Systems Engineering Review

    NASA Technical Reports Server (NTRS)

    Schmidt, H. W.; Forney, D. E.

    1975-01-01

    The design and safe operation of O2 systems at high pressures and temperatures are discussed. Data cover O2 reactivity with system materials, environmental limits, flow rate, contamination, and physical and chemical stresses of materials.

  5. Cost analysis of oxygen recovery systems

    NASA Technical Reports Server (NTRS)

    Yakut, M. M.

    1973-01-01

    The design and development of equipment for flight use in earth-orbital programs, when optimally approached cost effectively, proceed through the following logical progression: (1) bench testing of breadboard designs, (2) the fabrication and evaluation of prototype equipment, (3) redesign to meet flight-imposed requirements, and (4) qualification and testing of a flight-ready system. Each of these steps is intended to produce the basic design information necessary to progress to the next step. The cost of each step is normally substantially less than that of the following step. An evaluation of the cost elements involved in each of the steps and their impact on total program cost are presented. Cost analyses of four leading oxygen recovery subsystems which include two carbon dioxide reduction subsystem, Sabatier and Bosch, and two water electrolysis subsystems, the solid polymer electrolyte and the circulating KOH electrolyte are described.

  6. 77 FR 11385 - Security Considerations for Lavatory Oxygen Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-27

    ...-94, 25-133, 121-354, 129-50; SFAR 111] RIN 2120-AJ92 Security Considerations for Lavatory Oxygen... (Amendment Nos. 21-94, 25-133, 121-354, 129-50; SFAR 111) on security considerations for lavatory oxygen... oxygen systems installed inside the lavatories of most transport category airplanes. As a result, the...

  7. VASCULAR PLANTS AS ENGINEERS OF OXYGEN IN AQUATIC SYSTEMS

    EPA Science Inventory

    The impact of organisms on oxygen is one of the most dramatic examples of ecosystem engineering on Earth. In aquatic systems, which have much lower oxygen concentrations than the atmosphere, vascular aquatic plants can affect oxygen concentrations significantly not only on long t...

  8. Testing metals and alloys for use in oxygen systems

    NASA Technical Reports Server (NTRS)

    Stoltzfus, Joel M.

    1986-01-01

    When oxygen is present in high concentrations or large quantities, as in oxygen-based life-support systems, the likelihood of combustion and the probable intensity of a conflagration increase, together with the severity of the damage caused. Even stainless steel will burn vigorously when ignited in a 1000-psi oxygen environment. The hazards involved in the use of oxygen increase with system operation at the elevated temperatures typical of propulsion systems. Fires in oxygen systems are generally catastrophic, causing a threat to life in manned vehicles. When mechanical components of a mechanism generate friction heat in the presence of oxygen, many commonly used metal alloys ignite and burn. Attention is presently given to frictional heating, particle impact, and flame propagation tests conducted in oxygen environments.

  9. Safety Analysis for Naval Liquid Oxygen Life Support System

    DTIC Science & Technology

    1982-05-01

    6 2 Inter-tank piping arrangement for the liquid oxygen storage system ......... ................ 9 3 Oxygen flow control...that all explosions in LOX systems actually take place in the gaseous phase because: (a) The rapid " boil -off" rate of LOX forms an oxygen-rich...could be opened admitting GOX to the distribution system . When vaporization of LOX due to thermal in-leak is insufficient to provide the required flow

  10. Clinical tests of noninvasive optoacoustic cerebral venous oxygenation monitoring system

    NASA Astrophysics Data System (ADS)

    Petrov, Y. Y.; Petrova, I. Y.; Esenaliev, R. O.; Prough, D. S.

    2009-02-01

    Monitoring of cerebral venous oxygenation is critically important for management of patients with traumatic brain injury and cardiac surgery patients. At present, there is no technique for noninvasive, accurate monitoring of this important physiologic parameter. We built a compact optoacoustic system for noninvasive, accurate cerebral venous oxygenation monitoring using a novel optoacoustic probe and algorithm that allow for direct probing of sagittal sinus blood with minimal signal contamination from other tissues. We tested the system in large animal and clinical studies and identified wavelengths for accurate measurement of cerebral blood oxygenation. The studies demonstrated that the system may be used for noninvasive, continuous, and accurate monitoring of cerebral venous blood oxygenation.

  11. Visible light optical coherence tomography measures retinal oxygen metabolic response to systemic oxygenation

    PubMed Central

    Yi, Ji; Liu, Wenzhong; Chen, Siyu; Backman, Vadim; Sheibani, Nader; Sorenson, Christine M.; Fawzi, Amani A.; Linsenmeier, Robert A.; Zhang, Hao F.

    2015-01-01

    The lack of capability to quantify oxygen metabolism noninvasively impedes both fundamental investigation and clinical diagnosis of a wide spectrum of diseases including all the major blinding diseases such as age-related macular degeneration, diabetic retinopathy, and glaucoma. Using visible light optical coherence tomography (vis-OCT), we demonstrated accurate and robust measurement of retinal oxygen metabolic rate (rMRO2) noninvasively in rat eyes. We continuously monitored the regulatory response of oxygen consumption to a progressive hypoxic challenge. We found that both oxygen delivery, and rMRO2 increased from the highly regulated retinal circulation (RC) under hypoxia, by 0.28 ± 0.08 μL min−1 (p < 0.001), and 0.20 ± 0.04 μL min−1 (p < 0.001) per 100 mmHg systemic pO2 reduction, respectively. The increased oxygen extraction compensated for the deficient oxygen supply from the poorly regulated choroidal circulation. Results from an oxygen diffusion model based on previous oxygen electrode measurements corroborated our in vivo observations. We believe that vis-OCT has the potential to reveal the fundamental role of oxygen metabolism in various retinal diseases. PMID:26658555

  12. Oxygen cycling in the northern Benguela Upwelling System: Modelling oxygen sources and sinks

    NASA Astrophysics Data System (ADS)

    Schmidt, Martin; Eggert, Anja

    2016-12-01

    This paper elucidates the oxygen dynamics in the northern Benguela Upwelling System by means of process oriented, numerical modelling. Owing to the complex physical-biological interaction in this system, a coupled hydrodynamic-biogeochemical model is required to grasp the various aspects of the oxygen dynamics. We used high-resolution atmospheric fields derived from observations to force our model, available since 1999. The model results represent a 15 years, consistent data set of realistic hydrographic and ecosystem variables, including oxygen distribution patterns. After a concise description of the main aspects of the model, we use the model data to analyse the components contributing to the oxygen dynamics, namely, the ocean circulation, the exchange between ocean and atmosphere as well as the local biogeochemical oxygen cycling in the system. We thoroughly validate the model with available field observations and remote sensing data. The strengths of coastal upwelling, which controls the nutrient supply to the euphotic zone, as well as the poleward undercurrent that carries oxygen and nutrients to the shelf in the northern Benguela Upwelling System are well reproduced in the model. Among the biological oxygen sinks, mineralisation in the sediment, respiration of zooplankton and nitrification in the water column are important. We also found that vertical migration of zooplankton in response to the oxygen conditions provides a regulating feedback, which may prevent a complete deoxygenation of suboxic waters. As long as oxygen or nitrate are available in the bottom waters, the activities of chemolithoautotrophic sulphur bacteria on the sediment surface keep the redoxcline within the sediment and prevent the release of hydrogen sulphide into the water column. By horizontal integration of the simulated ocean-atmosphere oxygen flux, it can be shown that the Kunene upwelling cell between 16 ° S and 18 ° S is a boundary between the equatorial ocean, characterise by

  13. Precision Cleaning of Oxygen Systems and Components

    NASA Technical Reports Server (NTRS)

    McLaughlin, Russell

    2009-01-01

    Currently, NASA uses Dichloropentafluoropropane (HCFC-225), a Class II ozone depleting substance (ODs), to clean contaminated oxygen systems. Starting in 20 15, the Montreal Protocols and Clean Air Act prohibit the production and importation of all hydrochlorofluorocarbons (HCFC), except for limited use in refrigeration applications. Thus, a new non-ozone depleting solvent needs to be developed for use in cleaning. Optimally, such a solvent should also be environmentally benign or green to avoid needing to replace the new solvent with yet another solvent in the future due to other environmental concerns. Work for the first year consisted of two parts. The first part was developing a method of testing the cleaning efficiency of potential solvents. Stainless steel coupons were contaminated with a known weight of various contaminants and contaminant combinations and then immersed in solvent for ten minutes. The coupons were then removed and dried in an oven until all solvent had evaporated. Once dry, the coupons were weighed and the mass of the non-volatile residue (NVR) left on the coupon was determined. The cleaning efficiency of the solvents is reported as percent cleaning, with 100% cleaning being zero NVR left on the test coupon. The second half of the first goal was to use the develop method to perform baseline testing on current solvents. The second part of the work was to begin exploring alternative cleaning solvents. A variety of hydrofluorocarbons (HFCs) were tested. Preliminary testing was also performed with ionic liquids and aqueous surfactant solutions. Once potential solvents were identified, an analysis of the performance and environmental characteristics of each was to be conducted. Four contaminants were specified for use in testing. These are Mil-Spec-H-5606 (5606), a hydraulic fluid, Mil-H-83282B (83282), another hydraulic fluid, diethylhexyl sebacate (Sebacate), and WD-40. The structures of these contaminants are all similar, with long aliphatic

  14. Oxygen liquefaction and zero-loss storage system

    NASA Technical Reports Server (NTRS)

    Lin, F. N.; Bollo, T. R.; Peterson, D. M.

    1997-01-01

    This paper presents an alternative concept that employs existing technologies and off-the-shelf components to liquefy gaseous oxygen from an in-situ propellant production (ISPP) unit and to store the liquid oxygen without boil-off loss. A primary goal is to minimize active components with a secondary goal of designing the active component in a protected or failure-free environment. The resulting design requires only one active component, a compressor operating in a closed and consequently more protected system. The design avoids pumps as active components by employing cryopumping for gaseous oxygen (GOX) and gravity transfer for liquid oxygen (LOX).

  15. Fiber optic oxygen sensor leak detection system for space applications

    NASA Astrophysics Data System (ADS)

    Kazemi, Alex A.; Goswami, Kish; Mendoza, Edgar A.; Kempen, Lothar U.

    2007-09-01

    This paper describes the successful test of a multi-point fiber optic oxygen sensor system during the static firing of an Evolved Expandable Launch Vehicle (EELV)/Delta IV common booster core (CBC) rocket engine at NASA's Stennis Flight Center. The system consisted of microsensors (optrodes) using an oxygen gas sensitive indicator incorporated onto an optically transparent porous substrate. The modular optoelectronics and multiplexing network system was designed and assembled utilizing a multi-channel opto-electronic sensor readout unit that monitored the oxygen and temperature response of the individual optrodes in real-time and communicated this information via a serial communication port to a remote laptop computer. The sensor packaging for oxygen consisted of two optrodes - one doped with an indicator sensitive to oxygen, and the other doped with an indicator sensitive to temperature. The multichannel oxygen sensor system is fully reversible. It has demonstrated a dynamic response to oxygen gas in the range of 0% to 100% with 0.1% resolution and a response time of <=10 seconds. The sensor package was attached to a custom fiber optic ribbon cable, which was then connected to a fiber optic trunk communications cable (standard telecommunications-grade fiber) that connected to the optoelectronics module. Each board in the expandable module included light sources, photo-detectors, and associated electronics required for detecting oxygen and temperature. The paper illustrates the sensor design and performance data under field deployment conditions.

  16. Historic drawing. Oxygen Distribution Piping System, 1944. Photographic copy of ...

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

    Historic drawing. Oxygen Distribution Piping System, 1944. Photographic copy of original. Boston National Historical Park. Charlestown Navy Yard. BOSTS 13520, #631-1 - Charlestown Navy Yard, Oxygen Plant, Midway along northern boundary of Charlestown Navy Yard, on Little Mystic Channel, near junction of Eighteenth Street & Fourth Avenue, Boston, Suffolk County, MA

  17. Visible light optical coherence tomography measure retinal oxygen metabolic response to systemic oxygenation (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Yi, Ji; Liu, Wenzhong; Chen, Siyu; Backman, Vadim; Sheibani, Nader; Sorenson, Christine M.; Fawzi, Amani A.; Linsenmeier, Robert A.; Zhang, Hao F.

    2016-03-01

    The lack of capability to quantify oxygen metabolism noninvasively impedes both fundamental investigation and clinical diagnosis of a wide spectrum of diseases including all the major blinding diseases such as age-related macular degeneration, diabetic retinopathy, and glaucoma. Using visible light optical coherence tomography (vis-OCT), we demonstrated accurate and robust measurement of retinal oxygen metabolic rate (rMRO2) noninvasively in rat eyes. The rMRO2 was calculated by concurrent measurement of blood flow and blood oxygen saturation (sO2). Blood flow was calculated by the principle of Doppler optical coherence tomography, where the phase shift between two closely spaced A-lines measures the axial velocity. The distinct optical absorption spectra of oxy- and deoxy-hemoglobin provided the contrast for sO2 measurement, combined with the spectroscopic analysis of vis-OCT signal within the blood vessels. We continuously monitored the regulatory response of oxygen consumption to a progressive hypoxic challenge. We found that both oxygen delivery, and rMRO2 increased from the highly regulated retinal circulation (RC) under hypoxia, by 0.28+/-0.08 μL/min (p<0.001), and 0.20+/-0.04 μL/min (p<0.001) per 100 mmHg systemic pO2 reduction, respectively. The increased oxygen extraction compensated for the deficient oxygen supply from the poorly regulated choroidal circulation (CC).

  18. Reactive oxygen species in the immune system.

    PubMed

    Yang, Yuhui; Bazhin, Alexandr V; Werner, Jens; Karakhanova, Svetlana

    2013-06-01

    Reactive oxygen species (ROS) are a group of highly reactive chemicals containing oxygen produced either exogenously or endogenously. ROS are related to a wide variety of human disorders, such as chronic inflammation, age-related diseases and cancers. Besides, ROS are also essential for various biological functions, including cell survival, cell growth, proliferation and differentiation, and immune response. At present there are a number of excellent publications including some reviews about functions of these molecules either in normal cell biology or in pathophysiology. In this work, we reviewed available information and recent advances about ROS in the main immune cell types and gave summary about functions of these highly reactive molecules both in innate immunity as conservative defense mechanisms and in essential immune cells involved in adaptive immunity, and particularly in immune suppression.

  19. Full system engineering design and operation of an oxygen plant

    NASA Technical Reports Server (NTRS)

    Colvin, James; Schallhorn, Paul; Ramonhalli, Kumar

    1992-01-01

    The production of oxygen from the indigenous resources on Mars is described. After discussing briefly the project's background and the experimental system design, specific experimental results of the electrolytic cell are presented. At the heart of the oxygen production system is a tubular solid zirconia electrolyte cell that will electrochemically separate oxygen from a high-temperature stream of Coleman grade carbon dioxide. Experimental results are discussed and certain system efficiencies are defined. The parameters varied include (1) the cell operating temperature; (2) the carbon dioxide flow rate; and (3) the voltage applied across the cell. The results confirm our theoretical expectations.

  20. Oxygen Compatibility of Brass-Filled PTFE Compared to Commonly Used Fluorinated Polymers for Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Herald, Stephen D.; Frisby, Paul M.; Davis, Samuel Eddie

    2009-01-01

    Safe and reliable seal materials for high-pressure oxygen systems sometimes appear to be extinct species when sought out by oxygen systems designers. Materials that seal well are easy to find, but these materials are typically incompatible with oxygen, especially in cryogenic liquid form. This incompatibility can result in seals that leak, or much worse, seals that easily ignite and burn during use. Materials that are compatible with oxygen are easy to find, such as the long list of compatible metals, but these metallic materials are limiting as seal materials. A material that seals well and is oxygen compatible has been the big game in the designer's safari. Scientists at the Materials Combustion Research Facility (MCRF), part of NASA/Marshall Space Flight Center (MSFC), are constantly searching for better materials and processes to improve the safety of oxygen systems. One focus of this effort is improving the characteristics of polymers used in the presence of an oxygen enriched environment. Very few systems can be built which contain no polymeric materials; therefore, materials which have good impact resistance, low heat of combustion, high auto-ignition temperature and that maintain good mechanical properties are essential. The scientists and engineers at the Materials Combustion Research Facility, in cooperation with seal suppliers, are currently testing a new formulation of polytetrafluoroethylene (PTFE) with Brass filler. This Brass-filled PTFE is showing great promise as a seal and seat material for high pressure oxygen systems. Early research has demonstrated very encouraging results, which could rank this material as one of the best fluorinated polymers ever tested. This paper will compare the data obtained for Brass-filled PTFE with other fluorinated polymers, such as TFE-Teflon (PTFE) , Kel-F 81, Viton A, Viton A-500, Fluorel , and Algoflon . A similar metal filled fluorinated polymer, Salox-M , was tested in comparison to Brass-filled PTFE to

  1. Postflight Analysis of the Apollo 14 Cryogenic Oxygen System

    NASA Technical Reports Server (NTRS)

    Rule, D. D.

    1972-01-01

    A postflight analysis of the Apollo 14 cryogenic oxygen system is presented. The subjects discussed are: (1) methods of analysis, (2) stratification and heat transfer, (3) flight analysis, (4) postflight analysis, and (5) determination of model parameters.

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

    DOEpatents

    Staiger, Chad L [Albuquerque, NM; Vaughn, Mark R [Albuquerque, NM; Miller, A Keith [Albuquerque, NM; Cornelius, Christopher J [Blackburg, VA

    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.

  3. Evaluation of Solvent Alternatives for Cleaning of Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Beeson, Harold; Biesinger, Paul; Delgado, Rafael; Antin, Neil

    1999-01-01

    The NASA White Sands Test Facility (WSTF) in a joint program with the Naval Sea Systems Command has evaluated a number of solvents as alternatives to the use of chlorofluorocarbons currently utilized for cleaning of oxygen systems. Particular attention has been given to the cleaning of gauges and instrumentation used in oxygen service, since there have been no identified aqueous alternatives. The requirements identified as selection criteria, include toxicity, physical properties consistent with application, flammability, oxygen compatibility, and cleaning ability. This paper provides a summary of results and recommendations for solvents evaluated to date.

  4. A Control System for Oxygen Therapy of Premature Infants

    DTIC Science & Technology

    2007-11-02

    prevented to avoid retinopathy of prematurity , edema of the lungs, and other untoward effects of hyperoxia and oxygen toxicity. Several control systems have... effects of shunt in the lungs, a varying dead space, and prematurity of arterial receptors in infants are included. Lungs, brain, cerebrospinal fluid, and...A CONTROL SYSTEM FOR OXYGEN THERAPY OF PREMATURE INFANTS F. T. Tehrani Department of Electrical Engineering, California State University, Fullerton

  5. Reactive oxygen species and the cardiovascular system.

    PubMed

    Taverne, Yannick J H J; Bogers, Ad J J C; Duncker, Dirk J; Merkus, Daphne

    2013-01-01

    Ever since the discovery of free radicals, many hypotheses on the deleterious actions of reactive oxygen species (ROS) have been proposed. However, increasing evidence advocates the necessity of ROS for cellular homeostasis. ROS are generated as inherent by-products of aerobic metabolism and are tightly controlled by antioxidants. Conversely, when produced in excess or when antioxidants are depleted, ROS can inflict damage to lipids, proteins, and DNA. Such a state of oxidative stress is associated with many pathological conditions and closely correlated to oxygen consumption. Although the deleterious effects of ROS can potentially be reduced by restoring the imbalance between production and clearance of ROS through administration of antioxidants (AOs), the dosage and type of AOs should be tailored to the location and nature of oxidative stress. This paper describes several pathways of ROS signaling in cellular homeostasis. Further, we review the function of ROS in cardiovascular pathology and the effects of AOs on cardiovascular outcomes with emphasis on the so-called oxidative paradox.

  6. Preclinical and clinical validation of a novel oxygenation imaging system

    NASA Astrophysics Data System (ADS)

    Gioux, Sylvain; Mazhar, Amaan; Lee, Bernard T.; Cuccia, David J.; Stockdale, Alan; Oketokoun, Rafiou; Ashitate, Yoshitomo; Durr, Nicholas; Durkin, Anthony J.; Tromberg, Bruce J.; Frangioni, John V.

    2011-02-01

    Introduction: Two major disadvantages of currently available oxygenation probes are the need for contact with the skin and long measurement stabilization times. A novel oxygenation imaging device based on spatial frequency domain and spectral principles has been designed, validated preclinically on pigs, and validated clinically on humans. Importantly, this imaging system has been designed to operate under the rigorous conditions of an operating room. Materials and Methods: Optical properties reconstruction and wavelength selection have been optimized to allow fast and reliable oxyhemoglobin and deoxyhemoglobin imaging under realistic conditions. In vivo preclinical validation against commercially available contact oxygenation probes was performed on pigs undergoing arterial and venous occlusions. Finally, the device was used clinically to image skin flap oxygenation during a pilot study on women undergoing breast reconstruction after mastectomy. Results: A novel illumination head containing a spatial light modulator (SLM) and a novel fiber-coupled high power light source were constructed. Preclinical experiments showed similar values between local probes and the oxygenation imaging system, with measurement times of the new system being < 500 msec. During pilot clinical studies, the imaging system was able to provide near real-time oxyHb, deoxyHb, and saturation measurements over large fields of view (> 300 cm2). Conclusion: A novel optical-based oxygenation imaging system has the potential to replace contact probes during human surgery and to provide quantitative, wide-field measurements in near real-time.

  7. [The Status of Hemostasis System in Hypoxic Nitrogen-Oxygen and Argon-Oxygen Diving Gases].

    PubMed

    Kuzichkin, D S; Markin, A A; Juravlyova, O A; Morukov, B V; Zabolotskaya, I V; Vostrikova, L V

    2015-01-01

    In this study the effect of factors of hermetic chamber with modified gas medium on the hemostasis system is analyzed in order to estimate and to compare different diving breathing gases. The parameters characterizing pro-, anticoagulant as well as fibrinolytic components of hemostasis were determined using clotting, chromogenic and immunological methods. The applied exposure did not affect the activity and regulatory potential of hemostasis significantly; however, the nitrogen-oxygen and argon-oxygen diving gases have a different effect on the hemostasis functioning, especially in the recovery period.

  8. Oxygen Penalty for Waste Oxidation in an Advanced Life Support System: A Systems Approach

    NASA Technical Reports Server (NTRS)

    Pisharody, Suresh; Wignarajah, K.; Fisher, John

    2002-01-01

    Oxidation is one of a number of technologies that are being considered for waste management and resource recovery from waste materials generated on board space missions. Oxidation processes are a very effective and efficient means of clean and complete conversion of waste materials to sterile products. However, because oxidation uses oxygen there is an "oxygen penalty" associated either with resupply of oxygen or with recycling oxygen from some other source. This paper is a systems approach to the issue of oxygen penalty in life support systems and presents findings on the oxygen penalty associated with an integrated oxidation-Sabatier-Oxygen Generation System (OGS) for waste management in an Advanced Life Support System. The findings reveal that such an integrated system can be operated to form a variety of useful products without a significant oxygen penalty.

  9. Emergency Oxygen System Evaluation for Exploration PLSS Applications

    NASA Technical Reports Server (NTRS)

    Heather, Paul; Vonau, Walt, Jr.; Conger, Bruce

    2006-01-01

    The Portable Life Support System (PLSS) emergency oxygen system is being reexamined for the next generation of suits. These suits will be used for transit to Low Earth Orbit, the Moon and to Mars as well as on the surface of the Moon and Mars. Currently, the plan is that there will be two different sets of suits, but there is a strong desire for commonality between them for construction purposes. The main purpose of this paper is to evaluate what the emergency PLSS requirements are and how they might best be implemented. Options under consideration are enlarging the tanks on the PLSS, finding an alternate method of storage/delivery, or providing additional O2 from an external source. The system that shows the most promise is the cryogenic oxygen system with a composite dewar which uses a buddy system to split the necessary oxygen between two astronauts.

  10. System Modeling of Lunar Oxygen Production: Mass and Power Requirements

    NASA Technical Reports Server (NTRS)

    Steffen, Christopher J.; Freeh, Joshua E.; Linne, Diane L.; Faykus, Eric W.; Gallo, Christopher A.; Green, Robert D.

    2007-01-01

    A systems analysis tool for estimating the mass and power requirements for a lunar oxygen production facility is introduced. The individual modeling components involve the chemical processing and cryogenic storage subsystems needed to process a beneficiated regolith stream into liquid oxygen via ilmenite reduction. The power can be supplied from one of six different fission reactor-converter systems. A baseline system analysis, capable of producing 15 metric tons of oxygen per annum, is presented. The influence of reactor-converter choice was seen to have a small but measurable impact on the system configuration and performance. Finally, the mission concept of operations can have a substantial impact upon individual component size and power requirements.

  11. A system using solid ceramic oxygen electrolyte cells to measure oxygen fugacities in gas-mixing systems

    NASA Technical Reports Server (NTRS)

    Williams, R. J.; Mullins, O.

    1976-01-01

    Details are given for the construction and operation of a 101.3 kN/sq m (1 atmosphere) redox control system. A solid ceramic oxygen electrolyte cell is used to monitor the oxygen fugacity in the furnace. The system consists of a vertical quench, gas mixing furnace with heads designed for mounting the electrolyte cell and with facilities for inserting and removing the samples. The system also contains the high input impedance electronics necessary for measurements, a simplified version of a gas mixing apparatus, and devices for experiments under controlled rates of change relative to temperature and redox state. The calibration and maintenance of the system are discussed.

  12. Cavitating Jet Method and System for Oxygenation of Liquids

    NASA Technical Reports Server (NTRS)

    Chahine, Georges L.

    2012-01-01

    Reclamation and re-use of water is critical for space-based life support systems. A number of functions must be performed by any such system including removal of various contaminants and oxygenation. For long-duration space missions, this must be done with a compact, reliable system that requires little or no use of expendables and minimal power. DynaJets cavitating jets can oxidize selected organic compounds with much greater energy efficiency than ultrasonic devices typically used in sonochemistry. The focus of this work was to develop cavitating jets to simultaneously accomplish the functions of oxygenation and removal of contaminants of importance to space-structured water reclamation systems. The innovation is a method to increase the concentration of dissolved oxygen or other gasses in a liquid. It utilizes a particular form of novel cavitating jet operating at low to moderate pressures to achieve a high-efficiency means of transporting and mixing the gas into the liquid. When such a jet is utilized to simultaneously oxygenate the liquid and to oxidize organic compounds within the liquid, such as those in waste water, the rates of contaminant removal are increased. The invention is directed toward an increase in the dissolved gas content of a liquid, in general, and the dissolved oxygen content of a liquid in particular.

  13. Current Status of the Nitrogen Oxygen Recharge System

    NASA Technical Reports Server (NTRS)

    Dick, Brandon

    2011-01-01

    This paper presents an overview of the Nitrogen Oxygen Recharge System (NORS) to date and the current development status of the system. NORS is an element of the International Space Station (ISS) Environmental Control and Life Support Systems (ECLSS) used to resupply the ISS with Nitrogen and Oxygen following the impending retirement of the Space Shuttle. The paper will discuss why NASA is developing NORS, including a summary of other concepts considered, and other related concepts currently being developed by NASA. The current system architecture will be described, along with a summary of the current design of the NORS. The overall programmatic schedule of the NORS in the context of the upcoming shuttle retirement and future launch vehicle development will also be presented. Finally, the paper will examine the significant technical challenges encountered during the requirements and preliminary design phase of NORS development. A key challenge to the development of NORS is the international shipment - and associated regulations - of pressurized Oxygen, which is necessary due to the use of launch vehicles based in Japan and French Guiana to send NORS gasses to the ISS. The storage and use of relatively large quantities of high pressure (41,000 kPa) Oxygen and Nitrogen within the ISS, which is unprecedented both on the ISS and other space vehicles, has had a significant impact on the design and architecture of the system. The high pressure of the system also poses unique thermal considerations, which has led to the development of a heater system for thermal conditioning of high pressure gas to avoid thermal impacts on downstream hardware. The on-orbit envelope allocated to the NORS has changed (gotten smaller) and has impacted both the design and architecture of the system. Finally, the balance of safety considerations associated with these high pressure gasses, particularly high pressure Oxygen, with the functionality of the system has profoundly impacted the form

  14. An evaluation of oxygen systems for treatment of childhood pneumonia

    PubMed Central

    2011-01-01

    Background Oxygen therapy is recommended for all of the 1.5 – 2.7 million young children who consult health services with hypoxemic pneumonia each year, and the many more with other serious conditions. However, oxygen supplies are intermittent throughout the developing world. Although oxygen is well established as a treatment for hypoxemic pneumonia, quantitative evidence for its effect is lacking. This review aims to assess the utility of oxygen systems as a method for reducing childhood mortality from pneumonia. Methods Aiming to improve priority setting methods, The Child Health and Nutrition Research Initiative (CHNRI) has developed a common framework to score competing interventions into child health. That framework involves the assessment of 12 different criteria upon which interventions can be compared. This report follows the proposed framework, using a semi-systematic literature review and the results of a structured exercise gathering opinion from experts (leading basic scientists, international public health researchers, international policy makers and representatives of pharmaceutical companies), to assess and score each criterion as their “collective optimism” towards each, on a scale from 0 to 100%. Results A rough estimate from an analysis of the literature suggests that global strengthening of oxygen systems could save lives of up to 122,000 children from pneumonia annually. Following 12 CHNRI criteria, the experts expressed very high levels of optimism (over 80%) for answerability, low development cost and low product cost; high levels of optimism (60-80%) for low implementation cost, likelihood of efficacy, deliverability, acceptance to end users and health workers; and moderate levels of optimism (40-60%) for impact on equity, affordability and sustainability. The median estimate of potential effectiveness of oxygen systems to reduce the overall childhood pneumonia mortality was ~20% (interquartile range: 10-35%, min. 0%, max. 50%). However

  15. Comparison of the efficacy of a demand oxygen delivery system with continuous low flow oxygen in subjects with stable COPD and severe oxygen desaturation on walking.

    PubMed Central

    Roberts, C. M.; Bell, J.; Wedzicha, J. A.

    1996-01-01

    BACKGROUND: Provision of ambulatory oxygen using an intermittent pulsed flow regulated by a demand oxygen delivery system (DODS) greatly increases the limited supply time of standard portable gaseous cylinders. The efficacy of such a system has not previously been studied during submaximal exercise in subjects with severe chronic obstructive pulmonary disease (COPD) in whom desaturation is likely to be great and where usage is often most appropriate. METHODS: Fifteen subjects with severe COPD and oxygen desaturation underwent six minute walk tests performed in random order to compare the efficacy of a demand oxygen delivery system (DODS) with continuous flow oxygen. Walk distance, breathlessness, oxygen saturation, resting time, and recovery time (objective and subjective) were recorded and compared for each walk. RESULTS: Breathing continuous oxygen compared with baseline air breathing improved mean walk distance (295 m versus 271 m) and recovery time (47 seconds versus 112 seconds), whilst the lowest recorded saturation (81% versus 74%) and time desaturated below 90% (201 seconds versus 299 seconds) were reduced. When the DODS was compared with air breathing only the walk distance changed (283 m versus 271 m). A comparison of the DODS with continuous oxygen breathing showed the DODS to be less effective at oxygenating subjects with inferior lowest saturation (78% versus 81%), time spent below 90% (284 seconds versus 201 seconds), time to objective recovery (83 seconds versus 47 seconds), and walk distance (283 m versus 295 m). CONCLUSIONS: Neither of the delivery systems was able to prevent desaturation in these subjects. The use of continuous flow oxygen, however, was accompanied by improvements in oxygenation, walk distance, and recovery time compared with air breathing. The DODS produced only a small increase in walk distance without elevation of oxygen saturation, but was inferior to continuous flow oxygen in most of the measured variables when compared

  16. A thermodynamic study of the tantalum-oxygen system.

    SciTech Connect

    Hong, H. S.; Kim, Y. S.

    2001-09-07

    An evaluation of the partial thermodynamic functions of the tantalum-oxygen system (up to O/Ta = 2.5) over the temperature range from 873 K to 3120 K is presented. The pressure-composition-temperature (p-C-T) relationship in the single-phase region of solid Ta has been investigated. The relationships for other phases where no data were available from the literature have been proposed by using thermodynamic analysis. The results are presented as the oxygen isobars superimposed on the phase diagram.

  17. On the mean oxygen isotope composition of the Solar System

    NASA Astrophysics Data System (ADS)

    Ozima, M.; Podosek, F. A.; Higuchi, T.; Yin, Q.-Z.; Yamada, A.

    2007-02-01

    Since the first discovery of extraordinary oxygen isotope compositions in carbonaceous meteorites by Clayton et al. [Clayton, R.N., Grossman, L., Mayeda, T.K., 1973. Science 182, 485-488], numerous studies have been done to explain the unusual mass-independent isotope fractionation, but the problem is still unresolved to this day. Clayton's latest interpretation [Clayton, R.N., 2002. Nature 415, 860-861] sheds new light on the problem, and possible hypotheses now seem to be fairly well defined. A key issue is to resolve whether the oxygen isotopes in the Solar System represented by the Sun (solar oxygen) are the same as oxygen isotopes in planetary objects such as bulk meteorites, Mars, Earth, and Moon, or whether the solar oxygen is more similar to the lightest oxygen isotopes observed in CAIs (Calcium Aluminum-rich Inclusions) in primitive meteorites. Here, we examined the problem using oxygen isotope analytical data of about 400 bulk meteorite samples of various classes or types (data compiled by K. Lodders). We used in our discussion exclusively the parameter Δ 17O, a direct measure of the degree of mass-independent isotope fractionation of oxygen isotopes. When Δ 17O is arranged according to a characteristic size of their host planetary object, it shows a systematic trend: (1) Δ 17O values scatter around zero; (2) the scatter from the mean (Δ 17O=0) decreases with increasing representative size of the respective host planetary object. This systematic trend is easily understood on the basis of a hierarchical scenario of planetary formation, that is, larger planetary objects have formed by progressive accretion of planetesimals by random sampling over a wide spectrum of proto-solar materials. If this progressive random sampling of planetesimals were the essential process of planetary formation, the isotopic composition of planetary oxygen should approach that of the solar oxygen. To test this random sampling hypothesis, we applied a multiscale, multistep

  18. Photothermal imaging bundle system for estimating tissue oxygen saturation

    NASA Astrophysics Data System (ADS)

    Milstein, Yonat; Allon, Dror M.; Harrington, James; Bledt, Carlos; Gannot, Israel

    2012-01-01

    The objective of this study is to validate a method for the measurement of tissue oxygen saturation level via a thermal imaging bundle in-vitro and in-vivo. The method consists of a thermal imaging system and an algorithm which estimates the compound concentration according to the temperature rise of the tissue. A temperature rise is obtained by illuminating the tissue in the NIR range and is measured using a thermal camera and a coherent thermal imaging bundle for non-invasive transendoscopic use. The system was validated using agar phantoms of varying concentrations of Methylene Blue and ICG as well as blood samples. The algorithm estimated the Methylene Blue relative amount and the results were compared to the real relative amount. The calculated RMS of the error was 5.12%, a satisfying value for this stage. In the blood samples, for oxygenation levels higher than 50% the RMS of the error was 5.79%. Once the system was verified a portable system was built for clinical use, this system was also evaluated on agar phantoms and the RMS of the error was 10.64%. As a result of the encouraging experiments in-vivo, animal trials were performed. The oxygenation levels of mice were decreased and were estimated respectively using our system. The system determined a small decrease in the tissue oxygen saturation of the mice. These results verify the algorithm's and bundle's suitability for the use in a non-invasive system. They provide motivation for performing more complex in-vitro experiments and moving on to clinical trials.

  19. ISRU System Model Tool: From Excavation to Oxygen Production

    NASA Technical Reports Server (NTRS)

    Santiago-Maldonado, Edgardo; Linne, Diane L.

    2007-01-01

    In the late 80's, conceptual designs for an in situ oxygen production plant were documented in a study by Eagle Engineering [1]. In the "Summary of Findings" of this study, it is clearly pointed out that: "reported process mass and power estimates lack a consistent basis to allow comparison." The study goes on to say: "A study to produce a set of process mass, power, and volume requirements on a consistent basis is recommended." Today, approximately twenty years later, as humans plan to return to the moon and venture beyond, the need for flexible up-to-date models of the oxygen extraction production process has become even more clear. Multiple processes for the production of oxygen from lunar regolith are being investigated by NASA, academia, and industry. Three processes that have shown technical merit are molten regolith electrolysis, hydrogen reduction, and carbothermal reduction. These processes have been selected by NASA as the basis for the development of the ISRU System Model Tool (ISMT). In working to develop up-to-date system models for these processes NASA hopes to accomplish the following: (1) help in the evaluation process to select the most cost-effective and efficient process for further prototype development, (2) identify key parameters, (3) optimize the excavation and oxygen production processes, and (4) provide estimates on energy and power requirements, mass and volume of the system, oxygen production rate, mass of regolith required, mass of consumables, and other important parameters. Also, as confidence and high fidelity is achieved with each component's model, new techniques and processes can be introduced and analyzed at a fraction of the cost of traditional hardware development and test approaches. A first generation ISRU System Model Tool has been used to provide inputs to the Lunar Architecture Team studies.

  20. An Improved Approach for Analyzing the Oxygen Compatibility of Solvents and other Oxygen-Flammable Materials for Use in Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Harper, Susan A.; Juarez, Alfredo; Peralta, Stephen F.; Stoltzfus, Joel; Arpin, Christina Pina; Beeson, Harold D.

    2016-01-01

    Solvents used to clean oxygen system components must be assessed for oxygen compatibility, as incompatible residue or fluid inadvertently left behind within an oxygen system can pose a flammability risk. The most recent approach focused on solvent ignition susceptibility to assess the flammability risk associated with these materials. Previous evaluations included Ambient Pressure Liquid Oxygen (LOX) Mechanical Impact Testing (ASTM G86) and Autogenous Ignition Temperature (AIT) Testing (ASTM G72). The goal in this approach was to identify a solvent material that was not flammable in oxygen. As environmental policies restrict the available options of acceptable solvents, it has proven difficult to identify one that is not flammable in oxygen. A more rigorous oxygen compatibility approach is needed in an effort to select a new solvent for NASA applications. NASA White Sands Test Facility proposed an approach that acknowledges oxygen flammability, yet selects solvent materials based on their relative oxygen compatibility ranking, similar to that described in ASTM G63-99. Solvents are selected based on their ranking with respect to minimal ignition susceptibility, damage and propagation potential, as well as their relative ranking when compared with other solvent materials that are successfully used in oxygen systems. Test methods used in this approach included ASTM G86 (Ambient Pressure LOX Mechanical Impact Testing and Pressurized Gaseous Oxygen (GOX) Mechanical Impact Testing), ASTM G72 (AIT Testing), and ASTM D240 (Heat of Combustion (HOC) Testing). Only four solvents were tested through the full battery of tests for evaluation of oxygen compatibility: AK-225G as a baseline comparison, Solstice PF, L-14780, and Vertrel MCA. Baseline solvent AK-225G exhibited the lowest HOC and highest AIT of solvents tested. Nonetheless, Solstice PF, L-14780, and Vertrel MCA HOCs all fell well within the range of properties that are associated with proven oxygen system materials

  1. Hydrogen-Oxygen PEM Regenerative Fuel Cell Energy Storage System

    NASA Technical Reports Server (NTRS)

    Bents, David J.; Scullin, Vincent J.; Chang, Bei-Jiann; Johnson, Donald W.; Garcia, Christopher P.

    2005-01-01

    An introduction to the closed cycle hydrogen-oxygen polymer electrolyte membrane (PEM) regenerative fuel cell (RFC), recently constructed at NASA Glenn Research Center, is presented. Illustrated with explanatory graphics and figures, this report outlines the engineering motivations for the RFC as a solar energy storage device, the system requirements, layout and hardware detail of the RFC unit at NASA Glenn, the construction history, and test experience accumulated to date with this unit.

  2. Thermochemical Modeling of the Uranium-Cerium-Oxygen System

    SciTech Connect

    Voit, Stewart L; Besmann, Theodore M

    2010-10-01

    The objective of the Fuel Cycle R&D Program, Advanced Fuels campaign is to provide the research and development necessary to develop low loss, high quality nuclear fuels for ultra-high burnup reactor operation. Primary work in this area will be focused on the ceramic and metallic fuel systems. The goal of the current work is to enhance the understanding of ceramic nuclear fuel thermochemistry to support fuel research and development efforts. The thermochemical behavior of oxide nuclear fuel under irradiation is dependent on the oxygen to metal ratio (O:M). In fluorite-structured fuel, the actinide metal cation is bonded with {approx}2 oxygen atoms on a crystal lattice and as the metal atoms fission, fission fragments and free oxygen are created. The resulting fission fragments will contain some oxide forming elements, however these are insufficient to bind to all the liberated oxygen and therefore, there is an average increase in O:M with fuel burnup. Some of the fission products also form species that will migrate to and react with the cladding surface in a phenomenon known as Fuel Clad Chemical Interaction (FCCI). Cladding corrosion is life-limiting so it is desirable to understand influencing factors, such as oxide thermochemistry, which can be used to guide the design and fabrication of higher burn up fuel. A phased oxide fuel thermochemical model development effort is underway within the Advanced Fuels Campaign. First models of binary oxide systems are developed. For nuclear fuel system this means U-O and transuranic systems such as Pu-O, Np-O and Am-O. Next, the binary systems will be combined to form pseudobinary systems such as U-Pu-O, etc. The model development effort requires the use of data to allow optimization based on known thermochemical parameters as a function of composition and temperature. Available data is mined from the literature and supplemented by experimental work as needed. Due to the difficulty of performing fuel fabrication development

  3. Extravehicular mobility unit subcritical liquid oxygen storage and supply system

    NASA Technical Reports Server (NTRS)

    Anderson, John; Martin, Timothy; Hodgson, ED

    1992-01-01

    The storage of life support oxygen in the Extravehicular Mobility Unit in the liquid state offers some advantages over the current method of storing the oxygen as a high pressure gas. Storage volume is reduced because of the increased density associated with liquid. The lower storage and operating pressures also reduce the potential for leakage or bursting of the storage tank. The potential for combustion resulting from adiabatic combustion of the gas within lines and components is substantially reduced. Design constraints on components are also relaxed due to the lower system pressures. A design study was performed to determine the requirements for a liquid storage system and prepare a conceptual design. The study involved four tasks. The first was to identify system operating requirements that influence or direct the design of the system. The second was to define candidate storage system concepts that could possibly satisfy the requirements. An evaluation and comparison of the candidate concepts was conducted in the third task. The fourth task was devoted to preparing a conceptual design of the recommended storage system and to evaluate concerns with integration of the concept into the EMU. The results are presented.

  4. Alkaline static feed electrolyzer based oxygen generation system

    NASA Technical Reports Server (NTRS)

    Noble, L. D.; Kovach, A. J.; Fortunato, F. A.; Schubert, F. H.; Grigger, D. J.

    1988-01-01

    In preparation for the future deployment of the Space Station, an R and D program was established to demonstrate integrated operation of an alkaline Water Electrolysis System and a fuel cell as an energy storage device. The program's scope was revised when the Space Station Control Board changed the energy storage baseline for the Space Station. The new scope was aimed at the development of an alkaline Static Feed Electrolyzer for use in an Environmental Control/Life Support System as an oxygen generation system. As a result, the program was divided into two phases. The phase 1 effort was directed at the development of the Static Feed Electrolyzer for application in a Regenerative Fuel Cell System. During this phase, the program emphasized incorporation of the Regenerative Fuel Cell System design requirements into the Static Feed Electrolyzer electrochemical module design and the mechanical components design. The mechanical components included a Pressure Control Assembly, a Water Supply Assembly and a Thermal Control Assembly. These designs were completed through manufacturing drawing during Phase 1. The Phase 2 effort was directed at advancing the Alkaline Static Feed Electrolyzer database for an oxygen generation system. This development was aimed at extending the Static Feed Electrolyzer database in areas which may be encountered from initial fabrication through transportation, storage, launch and eventual Space Station startup. During this Phase, the Program emphasized three major areas: materials evaluation, electrochemical module scaling and performance repeatability and Static Feed Electrolyzer operational definition and characterization.

  5. Development of a novel electrochemical system for oxygen control (ESOC) to examine dissolved oxygen inhibition on algal activity.

    PubMed

    Keymer, Philip C; Pratt, Steven; Lant, Paul A

    2013-09-01

    The development of an Electrochemical System for Oxygen Control (ESOC) for examining algal photosynthetic activity as a function of dissolved oxygen (DO) is outlined. The main innovation of the tool is coulombic titration in order to balance the electrochemical reduction of oxygen with the oxygen input to achieve a steady DO set-point. ESOC allows quantification of algal oxygen production whilst simultaneously maintaining a desired DO concentration. The tool was validated abiotically by comparison with a mass transfer approach for quantifying oxygenation. It was then applied to quantify oxygen inhibition of algal activity. Five experiments, using an enriched culture of Scenedesmus sp. as the inoculum, are presented. For each experiment, ESOC was used to quantify algal activity at a series of DO set-points. In all experiments substantial oxygen inhibition was observed at DO >30 mgO2 L-1. Inhibition was shown to fit a Hill inhibition model, with a common Hill coefficient of 0.22±0.07 L mg-1 and common log10  CI50 of 27.2±0.7 mg L-1. This is the first time that the oxygen inhibition kinetic parameters have been quantified under controlled DO conditions.

  6. Artificial carrier for oxygen supply in biological systems.

    PubMed

    Dey, E S; Norrlöw, O; Liu, Y

    2004-04-01

    Several poly (dimethylsiloxanes) (PDMS) copolymers of dimethylsiloxane (DMS) with ethylene or propylene oxide were tested as artificial carriers for the delivery of oxygen to biological systems. Copolymers with a DMS content of 33% or lower enhanced glucose oxidation by 200% in contrast to the 25% increase produced by the same concentration of perfluorodecalin. When 0.05% of the copolymer with 18% DMS was included in the growth media of Bacillus thuriginensis, the biomass (growth rate) increased 1.5-fold. With 0.1% of this copolymer, actinorhodin production by Streptomyces coelicolor A3 (2) occurred in half the normal time and with an increased yield. In conclusion, these PDMS copolymers are a good alternative to perfluorodecalin as oxygen carriers in biotechnological processes.

  7. Nitrogen Oxygen Recharge System for the International Space Station

    NASA Technical Reports Server (NTRS)

    Williams, David E.; Dick, Brandon; Cook, Tony; Leonard, Dan

    2009-01-01

    The International Space Station (ISS) requires stores of Oxygen (O2) and Nitrogen (N2) to provide for atmosphere replenishment, direct crew member usage, and payload operations. Currently, supplies of N2/O2 are maintained by transfer from the Space Shuttle. Following Space Shuttle is retirement in 2010, an alternate means of resupplying N2/O2 to the ISS is needed. The National Aeronautics and Space Administration (NASA) has determined that the optimal method of supplying the ISS with O2/N2 is using tanks of high pressure N2/O2 carried to the station by a cargo vehicle capable of docking with the ISS. This paper will outline the architecture of the system selected by NASA and will discuss some of the design challenges associated with this use of high pressure oxygen and nitrogen in the human spaceflight environment.

  8. Oxygen Generation System Laptop Bus Controller Flight Software

    NASA Technical Reports Server (NTRS)

    Rowe, Chad; Panter, Donna

    2009-01-01

    The Oxygen Generation System Laptop Bus Controller Flight Software was developed to allow the International Space Station (ISS) program to activate specific components of the Oxygen Generation System (OGS) to perform a checkout of key hardware operation in a microgravity environment, as well as to perform preventative maintenance operations of system valves during a long period of what would otherwise be hardware dormancy. The software provides direct connectivity to the OGS Firmware Controller with pre-programmed tasks operated by on-orbit astronauts to exercise OGS valves and motors. The software is used to manipulate the pump, separator, and valves to alleviate the concerns of hardware problems due to long-term inactivity and to allow for operational verification of microgravity-sensitive components early enough so that, if problems are found, they can be addressed before the hardware is required for operation on-orbit. The decision was made to use existing on-orbit IBM ThinkPad A31p laptops and MIL-STD-1553B interface cards as the hardware configuration. The software at the time of this reporting was developed and tested for use under the Windows 2000 Professional operating system to ensure compatibility with the existing on-orbit computer systems.

  9. 14 CFR 25.1445 - Equipment standards for the oxygen distributing system.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Equipment standards for the oxygen... Miscellaneous Equipment § 25.1445 Equipment standards for the oxygen distributing system. (a) When oxygen is... crew on duty. (b) Portable walk-around oxygen units of the continuous flow, diluter-demand,...

  10. 14 CFR 25.1445 - Equipment standards for the oxygen distributing system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Equipment standards for the oxygen... Miscellaneous Equipment § 25.1445 Equipment standards for the oxygen distributing system. (a) When oxygen is... crew on duty. (b) Portable walk-around oxygen units of the continuous flow, diluter-demand,...

  11. 14 CFR 25.1445 - Equipment standards for the oxygen distributing system.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Equipment standards for the oxygen... Miscellaneous Equipment § 25.1445 Equipment standards for the oxygen distributing system. (a) When oxygen is... crew on duty. (b) Portable walk-around oxygen units of the continuous flow, diluter-demand,...

  12. 14 CFR 25.1445 - Equipment standards for the oxygen distributing system.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Equipment standards for the oxygen... Miscellaneous Equipment § 25.1445 Equipment standards for the oxygen distributing system. (a) When oxygen is... crew on duty. (b) Portable walk-around oxygen units of the continuous flow, diluter-demand,...

  13. 14 CFR 25.1445 - Equipment standards for the oxygen distributing system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Equipment standards for the oxygen... Miscellaneous Equipment § 25.1445 Equipment standards for the oxygen distributing system. (a) When oxygen is... crew on duty. (b) Portable walk-around oxygen units of the continuous flow, diluter-demand,...

  14. Systemic oxygen delivery and consumption in dogs with heartworm disease.

    PubMed

    Kitagawa, H; Kitoh, K; Yasuda, K; Sasaki, Y

    1995-02-01

    To investigate systemic oxygen (O2) transport, we calculated the oxygen delivery index (Do2I), oxygen consumption index (Vo2I) and oxygen extraction ratio (ER) in dogs with heartworm (HW) disease. The Do2I was 770 +/- 331 ml/min/kg in dogs mildly affected with pulmonary HW disease showing respiratory signs, mild anemia and mild cardiac insufficiency (n = 34); 238 +/- 155 ml/min/kg in dogs with ascitic pulmonary HW disease (n = 7); and 577 +/- 320 ml/min/kg in dogs with caval syndrome (CS) which survived (n = 15) or died (n = 7) after surgical HW removal. The Do2I was lower (P < 0.01) in all HW-infected groups, especially in ascites and CS-non-surviving dogs, than in HW-free dogs (n = 11, 1041 +/- 264 ml/min/kg). The Vo2I was higher in some mildly affected dogs (161 +/- 88 ml/min/kg), and lower (P < 0.01) in ascitic dogs (45 +/- 53 ml/min/kg) than in HW-free dogs (123 +/- 44 ml/min/kg). The ER was higher (P < 0.01) in all HW-infected groups than in HW-free dogs. The Do2I correlated significantly with Vo2I (r = 0.84, P < 0.01), and the Vo2I correlated significantly with ER (r = 0.48, P < 0.01). The Do2I correlated significantly with arterial O2 tension (r = 0.33), serum LDH (r = -0.46) and CK (r = -0.46) activities, serum urea nitrogen (UN, r = -0.32) and lactic acid (LA, r = -0.39) concentrations and cardiac index (r = 0.64).(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Techniques employed by the NASA White Sands Test Facility to ensure oxygen system component safety

    NASA Technical Reports Server (NTRS)

    Stradling, J. S.; Pippen, D. L.; Frye, G. W.

    1983-01-01

    Methods of ascertaining the safety and suitability of a variety of oxygen system components are discussed. Additionally, qualification and batch control requirements for soft goods in oxygen systems are presented. Current oxygen system component qualification test activities in progress at White Sands Test Facility are described.

  16. Integrated hydrogen/oxygen technology applied to auxiliary propulsion systems

    NASA Technical Reports Server (NTRS)

    Gerhardt, David L.

    1990-01-01

    The purpose of the Integrated Hydrogen/Oxygen Technology (IHOT) study was to determine if the vehicle/mission needs and technology of the 1990's support development of an all cryogenic H2/O2 system. In order to accomplish this, IHOT adopted the approach of designing Integrated Auxiliary Propulsion Systems (IAPS) for a representative manned vehicle; the advanced manned launch system. The primary objectives were to develop IAPS concepts which appeared to offer viable alternatives to state-of-the-art (i.e., hypergolic, or earth-storable) APS approaches. The IHOT study resulted in the definition of three APS concepts; two cryogenic IAPS, and a third concept utilizing hypergolic propellants.

  17. An oxygen-sensitive toxin–antitoxin system

    PubMed Central

    Marimon, Oriol; Teixeira, João M. C.; Cordeiro, Tiago N.; Soo, Valerie W. C.; Wood, Thammajun L.; Mayzel, Maxim; Amata, Irene; García, Jesús; Morera, Ainara; Gay, Marina; Vilaseca, Marta; Orekhov, Vladislav Yu; Wood, Thomas K.; Pons, Miquel

    2016-01-01

    The Hha and TomB proteins from Escherichia coli form an oxygen-dependent toxin–antitoxin (TA) system. Here we show that YmoB, the Yersinia orthologue of TomB, and its single cysteine variant [C117S]YmoB can replace TomB as antitoxins in E. coli. In contrast to other TA systems, [C117S]YmoB transiently interacts with Hha (rather than forming a stable complex) and enhances the spontaneous oxidation of the Hha conserved cysteine residue to a -SOxH-containing species (sulfenic, sulfinic or sulfonic acid), which destabilizes the toxin. The nuclear magnetic resonance structure of [C117S]YmoB and the homology model of TomB show that the two proteins form a four-helix bundle with a conserved buried cysteine connected to the exterior by a channel with a diameter comparable to that of an oxygen molecule. The Hha interaction site is located on the opposite side of the helix bundle. PMID:27929062

  18. Comparison of six oxygen delivery systems for COPD patients at rest and during exercise.

    PubMed

    Braun, S R; Spratt, G; Scott, G C; Ellersieck, M

    1992-09-01

    Five different oxygen-conserving devices were tested in each of ten oxygen-dependent patients with COPD who had met the NOTT criteria for continuous oxygen use. They were tested on room air, their prescribed continuous oxygen flow and then on each of the five devices. The devices which delivered a bolus of oxygen during early inspiration or increased oxygen delivery as the respiratory rate increased did better than those devices which delivered oxygen at a normal flow rate during inspiration or a fixed portion of inspiration. In at least one of the subjects each device was associated with desaturation to less than 80 percent during a 12-min walk. It is concluded that oxygen-conserving devices vary in their ability to maintain SaO2 levels during exercise. It is recommended that a home oxygen evaluation include measurement of an exercise SaO2 utilizing the prescribed oxygen delivery system.

  19. Liquid Nitrogen (Oxygen Simulant) Thermodynamic Vent System Test Data Analysis

    NASA Astrophysics Data System (ADS)

    Hedayat, A.; Nelson, S. L.; Hastings, L. J.; Flachbart, R. H.; Tucker, S. P.

    2006-04-01

    In designing systems for the long-term storage of cryogens in low-gravity (space) environments, one must consider the effects of thermal stratification on tank pressure that will occur due to environmental heat leaks. During low-gravity operations, a Thermodynamic Vent System (TVS) concept is expected to maintain tank pressure without propellant resettling. A series of TVS tests was conducted at NASA Marshall Space Flight Center (MSFC) using liquid nitrogen (LN2) as a liquid oxygen (LO2) simulant. The tests were performed at tank fill levels of 90%, 50%, and 25%, and with a specified tank pressure control band. A transient one-dimensional TVS performance program is used to analyze and correlate the test data for all three fill levels. Predictions and comparisons of ullage pressure and temperature and bulk liquid saturation pressure and temperature with test data are presented.

  20. Total hydrocarbon content (THC) testing in liquid oxygen (LOX) systems

    NASA Astrophysics Data System (ADS)

    Meneghelli, B. J.; Obregon, R. E.; Ross, H. R.; Hebert, B. J.; Sass, J. P.; Dirschka, G. E.

    2015-12-01

    The measured Total Hydrocarbon Content (THC) levels in liquid oxygen (LOX) systems at Stennis Space Center (SSC) have shown wide variations. Examples of these variations include the following: 1) differences between vendor-supplied THC values and those obtained using standard SSC analysis procedures; and 2) increasing THC values over time at an active SSC test stand in both storage and run vessels. A detailed analysis of LOX sampling techniques, analytical instrumentation, and sampling procedures will be presented. Additional data obtained on LOX system operations and LOX delivery trailer THC values during the past 12-24 months will also be discussed. Field test results showing THC levels and the distribution of the THC's in the test stand run tank, modified for THC analysis via dip tubes, will be presented.

  1. Liquid Nitrogen (Oxygen Simulant) Thermodynamic Vent System Test Data Analysis

    NASA Technical Reports Server (NTRS)

    Hedayat, A.; Nelson, S. L.; Hastings, L. J.; Flachbart, R. H.; Tucker, S. P.

    2005-01-01

    In designing systems for the long-term storage of cryogens in low-gravity (space) environments, one must consider the effects of thermal stratification on tank pressure that will occur due to environmental heat leaks. During low-gravity operations, a Thermodynamic Vent System (TVS) concept is expected to maintain tank pressure without propellant resettling. A series of TVS tests was conducted at NASA Marshall Space Flight Center (MSFC) using liquid nitrogen (LN2) as a liquid oxygen (LO2) simulant. The tests were performed at tank til1 levels of 90%, 50%, and 25%, and with a specified tank pressure control band. A transient one-dimensional TVS performance program is used to analyze and correlate the test data for all three fill levels. Predictions and comparisons of ullage pressure and temperature and bulk liquid saturation pressure and temperature with test data are presented.

  2. Pressure and Quantity Thresholds for Ignition of Oil Contamination by Rapid Pressurization in Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Tapia, Susana; Smith, Sarah; Peralta, Steve; Stoltzfus, Joel

    2009-01-01

    This slide presentation reviews the problem and solution of oil contamination and increased ignition hazard in oxygen systems. The experiments that were used are reviewed, and the contamination level threshold and the oxygen pressure threshold are reviewed.

  3. Liquid oxygen/liquid hydrogen auxiliary power system thruster investigation

    NASA Technical Reports Server (NTRS)

    Eberle, E. E.; Kusak, L.

    1979-01-01

    The design, fabrication, and demonstration of a 111 newton (25 lb) thrust, integrated auxiliary propulsion system (IAPS) thruster for use with LH2/LO2 propellants is described. Hydrogen was supplied at a temperature range of 22 to 33 K (40 to 60 R), and oxygen from 89 to 122 K (160 to 220 R). The thruster was designed to operate in both pulse mode and steady-state modes for vehicle attitude control, space maneuvering, and as an abort backup in the event of failure of the main propulsion system. A dual-sleeve, tri-axial injection system was designed that utilizes a primary injector/combustor where 100 percent of the oxygen and 8 percent of the hydrogen is introduced; a secondary injector/combustor where 45 percent of the hydrogen is introduced to mix with the primary combustor gases; and a boundary layer injector that uses the remaining 45 percent of the hydrogen to cool the thrust throat/nozzle design. Hot-fire evaluation of this thruster with a BLC injection distance of 2.79 cm (1.10 in.) indicated that a specific impulse value of 390 sec can be attained using a coated molybdenum thrust chamber. Pulse mode tests indicated that a chamber pressure buildup to 90 percent thrust can be achieved in a time on the order of 48 msec. Some problems were encountered in achieving ignition of each pulse during pulse trains. This was interpreted to indicate that a higher delivered spark energy level ( 100 mJ) would be required to maintain ignition reliability of the plasma torch ignition system under the extra 'cold' conditions resulting during pulsing.

  4. Liquid Oxygen/Liquid Methane Integrated Propulsion System Test Bed

    NASA Technical Reports Server (NTRS)

    Flynn, Howard; Lusby, Brian; Villemarette, Mark

    2011-01-01

    In support of NASA?s Propulsion and Cryogenic Advanced Development (PCAD) project, a liquid oxygen (LO2)/liquid methane (LCH4) Integrated Propulsion System Test Bed (IPSTB) was designed and advanced to the Critical Design Review (CDR) stage at the Johnson Space Center. The IPSTB?s primary objectives are to study LO2/LCH4 propulsion system steady state and transient performance, operational characteristics and to validate fluid and thermal models of a LO2/LCH4 propulsion system for use in future flight design work. Two phase thermal and dynamic fluid flow models of the IPSTB were built to predict the system performance characteristics under a variety of operating modes and to aid in the overall system design work. While at ambient temperature and simulated altitude conditions at the White Sands Test Facility, the IPSTB and its approximately 600 channels of system instrumentation would be operated to perform a variety of integrated main engine and reaction control engine hot fire tests. The pressure, temperature, and flow rate data collected during this testing would then be used to validate the analytical models of the IPSTB?s thermal and dynamic fluid flow performance. An overview of the IPSTB design and analytical model development will be presented.

  5. On Orbit ISS Oxygen Generation System Operation Status

    NASA Technical Reports Server (NTRS)

    Diderich, Greg S.; Polis, Pete; VanKeuren, Steven P.; Erickson, Robert; Mason, Richard

    2011-01-01

    The International Space Station (ISS) United States Orbital Segment (USOS) Oxygen Generation System (OGS) has accumulated almost a year of operation at varied oxygen production rates within the US Laboratory Module (LAB) since it was first activated in July 2007. It was operated intermittently through 2009 and 2010, due to filter clogging and acid accumulation in the recirculation loop. Since the installation of a deionizing bed in the recirculation loop in May of 2011 the OGA has been operated continuously. Filters in the recirculation loop have clogged and have been replaced. Hydrogen sensors have drifted apart, and a power failure may have condensed water on a hydrogen sensor. A pump delta pressure sensor failed, and a replacement new spare pump failed to start. Finally, the voltage across the cell stack increased out of tolerance due to cation contamination, and the cell stack was replaced. This paper will discuss the operating experience and characteristics of the OGS, as well as operational issues and their resolution.

  6. Atomic oxygen testing with thermal atom systems - A critical evaluation

    NASA Technical Reports Server (NTRS)

    Koontz, Steven L.; Albyn, Keith; Leger, Lubert J.

    1991-01-01

    The use of thermal atom (kinetic energy near 0.04 eV) test methods as a materials selection and screening technique for LEO spacecraft is critically evaluated in this paper. The physics and chemistry of the thermal atom environments are shown to produce specific mass loss rates (mg/sq cm per min) and reaction efficiencies (Re) radically different from those produced in the LEO environment. A response surface study shows that specific mass loss rates change rapidly with plasma-asher parameters and seldom agree with flight data. FEP Teflon is shown to react by a different mechanism than Kapton, polyethylene, or graphite. The Re (Re = volume of material removed/oxygen atom) of Kapton, polyethylene, Mylar, Tedlar, FEP Teflon, and graphite measured in a flowing afterglow apparatus are 0.001 to 0.0001 those measured with high-energy atoms (kinetic energy 1.5 eV or greater) in beam systems or in LEO. The effect of sample temperature and atom impact energy on Re is discussed. A simple kinetic model describing the reaction of atomic oxygen with polymer surfaces is developed. Guidelines and recommendations for thermal atom testing and interpretation of test results are presented.

  7. Oxygen-hydrogen thrusters for Space Station auxiliary propulsion systems

    NASA Technical Reports Server (NTRS)

    Berkman, D. K.

    1984-01-01

    The feasibility and technology requirements of a low-thrust, high-performance, long-life, gaseous oxygen (GO2)/gaseous hydrogen (GH2) thruster were examined. Candidate engine concepts for auxiliary propulsion systems for space station applications were identified. The low-thrust engine (5 to 100 lb sub f) requires significant departure from current applications of oxygen/hydrogen propulsion technology. Selection of the thrust chamber material and cooling method needed or long life poses a major challenge. The use of a chamber material requiring a minimum amount of cooling or the incorporation of regenerative cooling were the only choices available with the potential of achieving very high performance. The design selection for the injector/igniter, the design and fabrication of a regeneratively cooled copper chamber, and the design of a high-temperature rhenium chamber were documented and the performance and heat transfer results obtained from the test program conducted at JPL using the above engine components presented. Approximately 115 engine firings were conducted in the JPL vacuum test facility, using 100:1 expansion ratio nozzles. Engine mixture ratio and fuel-film cooling percentages were parametrically investigated for each test configuration.

  8. Oxygen discharge and post-discharge kinetics experiments and modeling for the electric oxygen-iodine laser system.

    PubMed

    Palla, A D; Zimmerman, J W; Woodard, B S; Carroll, D L; Verdeyen, J T; Lim, T C; Solomon, W C

    2007-07-26

    Laser oscillation at 1315 nm on the I(2P1/2)-->I(2P3/2) transition of atomic iodine has been obtained by a near resonant energy transfer from O2(a1Delta) produced using a low-pressure oxygen/helium/nitric oxide discharge. In the electric discharge oxygen-iodine laser (ElectricOIL) the discharge production of atomic oxygen, ozone, and other excited species adds levels of complexity to the singlet oxygen generator (SOG) kinetics which are not encountered in a classic purely chemical O2(a1Delta) generation system. The advanced model BLAZE-IV has been introduced to study the energy-transfer laser system dynamics and kinetics. Levels of singlet oxygen, oxygen atoms, and ozone are measured experimentally and compared with calculations. The new BLAZE-IV model is in reasonable agreement with O3, O atom, and gas temperature measurements but is under-predicting the increase in O2(a1Delta) concentration resulting from the presence of NO in the discharge and under-predicting the O2(b1Sigma) concentrations. A key conclusion is that the removal of oxygen atoms by NOX species leads to a significant increase in O2(a1Delta) concentrations downstream of the discharge in part via a recycling process; however, there are still some important processes related to the NOX discharge kinetics that are missing from the present modeling. Further, the removal of oxygen atoms dramatically inhibits the production of ozone in the downstream kinetics.

  9. Evaluation of a Stirling Solar Dynamic System for Lunar Oxygen Production

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.; Wong, Wayne A.

    2006-01-01

    An evaluation of a solar concentrator-based system for producing oxygen from the lunar regolith was performed. The system utilizes a solar concentrator mirror to provide thermal energy for the oxygen production process as well as thermal energy to power a Stirling heat engine for the production of electricity. The electricity produced is utilized to operate the equipment needed in the oxygen production process. The oxygen production method utilized in the analysis was the hydrogen reduction of ilmenite. Utilizing this method of oxygen production a baseline system design was produced. This baseline system had an oxygen production rate of 0.6 kg/hr with a concentrator mirror size of 5 m. Variations were performed on the baseline design to show how changes in the system size and process rate effected the oxygen production rate.

  10. Horizontally rotated cell culture system with a coaxial tubular oxygenator

    NASA Technical Reports Server (NTRS)

    Wolf, David A. (Inventor); Schwarz, Ray P. (Inventor); Trinh, Tinh T. (Inventor)

    1991-01-01

    The present invention relates to a horizontally rotating bioreactor useful for carrying out cell and tissue culture. For processing of mammalian cells, the system is sterilized and fresh fluid medium, microcarrier beads, and cells are admitted to completely fill the cell culture vessel. An oxygen containing gas is admitted to the interior of the permeable membrane which prevents air bubbles from being introduced into the medium. The cylinder is rotated at a low speed within an incubator so that the circular motion of the fluid medium uniformly suspends the microbeads throughout the cylinder during the cell growth period. The unique design of this cell and tissue culture device was initially driven by two requirements imposed by its intended use for feasibility studies for three dimensional culture of living cells and tissues in space by JSC. They were compatible with microgravity and simulation of microgravity in one G. The vessels are designed to approximate the extremely quiescent low shear environment obtainable in space.

  11. Simplified thermochemistry of oxygen in lithium and sodium for liquid metal cooling systems

    NASA Technical Reports Server (NTRS)

    Tower, L. K.

    1972-01-01

    Plots of oxygen chemical potential against composition of lithium-oxygen solutions and sodium-oxygen solutions for a range of temperature were constructed. For each liquid metal two such plots were prepared. For one plot ideal solution behavior was assumed. For the other plot, existing solubility limit data for oxygen in the liquid metal were used to determine a first-order term for departure from ideality. The use of the plots in evaluating the oxygen gettering capability of refractory metals in liquid metal cooling systems is illustrated by a simple example involving lithium, oxygen, and hafnium.

  12. Lunar and Planetary Science XXXV: Special Session: Oxygen in the Solar System, II

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The Special Session: Oxygen in the Solar System, II, included the following reports:Evolution of Oxygen Isotopes in the Solar Nebula; Disequilibrium Melting of Refractory Inclusions: A Mechanism for High-Temperature Oxygen; Isotope Exchange in the Solar Nebula; Oxygen Isotopic Compositions of the Al-rich Chondrules in the CR Carbonaceous Chondrites: Evidence for a Genetic Link to Ca-Al-rich Inclusions and for Oxygen Isotope Exchange During Chondrule Melting; Nebular Formation of Fayalitic Olivine: Ineffectiveness of Dust Enrichment; Water in Terrestrial Planets: Always an Oxidant?; Oxygen Barometry of Basaltic Glasses Based on Vanadium Valence Determination Using Synchrotron MicroXANES; A New Oxygen Barometer for Solar System Basaltic Glasses Based on Vanadium Valence; The Relationship Between Clinopyroxene Fe3+ Content and Oxygen Fugacity ; and Olivine-Silicate Melt Partitioning of Iridium.

  13. Development of modified poly(perfluoropropyleneoxide) urethane systems for use in liquid oxygen and in enriched 100 percent oxygen atmosphere

    NASA Technical Reports Server (NTRS)

    Harrison, E. S.

    1973-01-01

    This program consisted of two separate though related phases. The initial phase was directed toward improving the mechanical and adhesive properties of the very highly fluorinated-polyurethane resin system derived from the hydroxyl-terminated polyperfluoropropylene oxide and 6-chloro-2,4,5-trifluoro-m-phenylene diisocyanate. Various new curing agents for this system were investigated, with the goal of providing a more thermally stable crosslink (cure) mechanism to provide wider applicability and fuller utilization of the outstanding oxygen resistance of the PFPO system. Complete resistance to liquid- and gaseous-oxygen impact at presures as high as 1035 N/sq cm were attained with the use of the PFPO resin castings. The second corollary phase was directed toward investigating the feasibility and optimization of the allophanate cured, urethane extended polymer derived from hydroxyl-terminated polyperfluoropropyleneoxide and 6-chloro-2,4,5-trifluoro-m-phenylene diisocyanate, as the adhesive system for use in a weld-bond configuration for liquid oxygen tankage. The synthesis and application procedures of the adhesive system to insure liquid oxygen compatibility (under 10 kg-m loading), and the development of procedures and techniques to provide high quality weld-bonded joint configurations were studied.

  14. Biochemical oxygen demand measurement by mediator method in flow system.

    PubMed

    Liu, Ling; Bai, Lu; Yu, Dengbin; Zhai, Junfeng; Dong, Shaojun

    2015-06-01

    Using mediator as electron acceptor for biochemical oxygen demand (BOD) measurement was developed in the last decade (BODMed). However, until now, no BOD(Med) in a flow system has been reported. This work for the first time describes a flow system of BOD(Med) method (BOD(Med)-FS) by using potassium ferricyanide as mediator and carbon fiber felt as substrate material for microbial immobilization. The system can determine the BOD value within 30 min and possesses a wider analytical linear range for measuring glucose-glutamic acid (GGA) standard solution from 2 up to 200 mg L(-1) without the need of dilution. The analytical performance of the BOD(Med)-FS is comparable or better than that of the previously reported BOD(Med) method, especially its superior long-term stability up to 2 months under continuous operation. Moreover, the BOD(Med)-FS has same determination accuracy with the conventional BOD5 method by measuring real samples from a local wastewater treatment plant (WWTP).

  15. Extreme oxygen isotope ratios in the early Solar System.

    PubMed

    Aléon, Jérôme; Robert, François; Duprat, Jean; Derenne, Sylvie

    2005-09-15

    The origins of the building blocks of the Solar System can be studied using the isotopic composition of early planetary and meteoritic material. Oxygen isotopes in planetary materials show variations at the per cent level that are not related to the mass of the isotopes; rather, they result from the mixture of components having different nucleosynthetic or chemical origins. Isotopic variations reaching orders of magnitude in minute meteoritic grains are usually attributed to stellar nucleosynthesis before the birth of the Solar System, whereby different grains were contributed by different stars. Here we report the discovery of abundant silica-rich grains embedded in meteoritic organic matter, having the most extreme 18O/16O and 17O/16O ratios observed (both approximately 10(-1)) together with a solar silicon isotopic composition. Both O and Si isotopes indicate a single nucleosynthetic process. These compositions can be accounted for by one of two processes: a single exotic evolved star seeding the young Solar System, or irradiation of the circumsolar gas by high energy particles accelerated during an active phase of the young Sun. We favour the latter interpretation, because the observed compositions are usually not expected from nucleosynthetic processes in evolved stars, whereas they are predicted by the selective trapping of irradiation products.

  16. Liquid Oxygen Thermodynamic Vent System Testing with Helium Pressurization

    NASA Technical Reports Server (NTRS)

    VanDresar, Neil T.

    2014-01-01

    This report presents the results of several thermodynamic vent system (TVS) tests with liquid oxygen plus a test with liquid nitrogen. In all tests, the liquid was heated above its normal boiling point to 111 K for oxygen and 100 K for nitrogen. The elevated temperature was representative of tank conditions for a candidate lunar lander ascent stage. An initial test series was conducted with saturated oxygen liquid and vapor at 0.6 MPa. The initial series was followed by tests where the test tank was pressurized with gaseous helium to 1.4 to 1.6 MPa. For these tests, the helium mole fraction in the ullage was quite high, about 0.57 to 0.62. TVS behavior is different when helium is present than when helium is absent. The tank pressure becomes the sum of the vapor pressure and the partial pressure of helium. Therefore, tank pressure depends not only on temperature, as is the case for a pure liquid-vapor system, but also on helium density (i.e., the mass of helium divided by the ullage volume). Thus, properly controlling TVS operation is more challenging with helium pressurization than without helium pressurization. When helium was present, the liquid temperature would rise with each successive TVS cycle if tank pressure was kept within a constant control band. Alternatively, if the liquid temperature was maintained within a constant TVS control band, the tank pressure would drop with each TVS cycle. The final test series, which was conducted with liquid nitrogen pressurized with helium, demonstrated simultaneous pressure and temperature control during TVS operation. The simultaneous control was achieved by systematic injection of additional helium during each TVS cycle. Adding helium maintained the helium partial pressure as the liquid volume decreased because of TVS operation. The TVS demonstrations with liquid oxygen pressurized with helium were conducted with three different fluid-mixer configurations-a submerged axial jet mixer, a pair of spray hoops in the tank

  17. Space shuttle auxiliary propulsion system design study. Phase D report: Oxygen-hydrogen special RCS studies

    NASA Technical Reports Server (NTRS)

    Baumann, T. L.; Pattern, T. C.; Mckee, H. B.

    1972-01-01

    Two alternate oxygen-hydrogen auxiliary propulsion system concepts for use with the space shuttle vehicle were evaluated. The two concepts considered were: (1) gaseous oxygen-hydrogen systems with electric or hydraulic motor driven pumps to provide system pressure and (2) liquid oxygen-hydrogen systems which delivered propellants to the engines in a liquid state without the need for pumps. The various means of implementing each of the concepts are compared on the basis of weight, technology requirements, and operational considerations. It was determined that the liquid oxygen-hydrogen system concepts have the potential to produce substantial weight reductions in the space shuttle orbiter total impulse range.

  18. Chemical oxygen demand using closed microwave digestion system.

    PubMed

    Dharmadhikari, Dattatray M; Vanerkar, Atul P; Barhate, Nivedita M

    2005-08-15

    A new approach to determine the chemical oxygen demand (COD) using a closed microwave digestion (CMD) system to replace the conventional, time-consuming open reflux (OR) method is proposed. The procedure uses a laboratory-grade closed microwave digestion system (one magnetron) for the digestion of small volume of samples (3.0 mL) in a completely closed (90 mL) Teflon vessel, digesting 10 samples at a time in the range of COD values of 5-1000 mg L(-1). The digestion time required is 15 min as compared to the 2 h required for the conventional OR method. Chloride ion interference can be removed up to 6000 mg of Cl- ions L(-1) as compared to the 2000 mg of Cl- ions L(-1) removed by conventional OR method. The present work reveals that the filtration of effluent samples by membrane filter or homogenization is not essential to obtain reproducible results. The proposed method is cost-effective; saves time, energy, and reagents with providing precise results for both the pure organic compounds and wastewater samples; and is ecofriendly.

  19. Liquid Nitrogen (Oxygen Simulent) Thermodynamic Venting System Test Data Analysis

    NASA Technical Reports Server (NTRS)

    Hedayat, A.; Nelson, S. L.; Hastings, L. J.; Flachbart, R. H.; Tucker, S. P.

    2005-01-01

    In designing systems for the long-term storage of cryogens in low gravity space environments, one must consider the effects of thermal stratification on excessive tank pressure that will occur due to environmental heat leakage. During low gravity operations, a Thermodynamic Venting System (TVS) concept is expected to maintain tank pressure without propellant resettling. The TVS consists of a recirculation pump, Joule-Thomson (J-T) expansion valve, and a parallel flow concentric tube heat exchanger combined with a longitudinal spray bar. Using a small amount of liquid extracted by the pump and passing it though the J-T valve, then through the heat exchanger, the bulk liquid and ullage are cooled, resulting in lower tank pressure. A series of TVS tests were conducted at the Marshall Space Flight Center using liquid nitrogen as a liquid oxygen simulant. The tests were performed at fill levels of 90%, 50%, and 25% with gaseous nitrogen and helium pressurants, and with a tank pressure control band of 7 kPa. A transient one-dimensional model of the TVS is used to analyze the data. The code is comprised of four models for the heat exchanger, the spray manifold and injector tubes, the recirculation pump, and the tank. The TVS model predicted ullage pressure and temperature and bulk liquid saturation pressure and temperature are compared with data. Details of predictions and comparisons with test data regarding pressure rise and collapse rates will be presented in the final paper.

  20. ASRDI oxygen technology survey, Volume 7: Characteristics of metals that influence system safety

    NASA Technical Reports Server (NTRS)

    Pelouch, J. J., Jr.

    1974-01-01

    A literature survey and analysis of the material and process factors affecting the safety of metals in oxygen systems is presented. In addition, the practices of those who specify, build, or use oxygen systems relative to the previous is summarized. Alloys based on iron, copper, nickel, and aluminum were investigated representing the bulk of metals found in oxygen systems. Safety-related characteristics of other miscellaneous metals are summarized. It was found that factors affecting the safety of metals in oxygen systems exit in all phases of the evolutionary process, from smelting and mill techniques through end-production fabrication. The safety of a given metal in an oxygen system was determined to be influenced by the particular service requirement. The metal characteristics should favorably influence fulfillment of these requirements. Thus, no singular metal or alloy could be classified as safest for all types of oxygen service.

  1. Systemic Reprogramming of Translation Efficiencies on Oxygen Stimulus.

    PubMed

    Ho, J J David; Wang, Miling; Audas, Timothy E; Kwon, Deukwoo; Carlsson, Steven K; Timpano, Sara; Evagelou, Sonia L; Brothers, Shaun; Gonzalgo, Mark L; Krieger, Jonathan R; Chen, Steven; Uniacke, James; Lee, Stephen

    2016-02-16

    Protein concentrations evolve under greater evolutionary constraint than mRNA levels. Translation efficiency of mRNA represents the chief determinant of basal protein concentrations. This raises a fundamental question of how mRNA and protein levels are coordinated in dynamic systems responding to physiological stimuli. This report examines the contributions of mRNA abundance and translation efficiency to protein output in cells responding to oxygen stimulus. We show that changes in translation efficiencies, and not mRNA levels, represent the major mechanism governing cellular responses to [O2] perturbations. Two distinct cap-dependent protein synthesis machineries select mRNAs for translation: the normoxic eIF4F and the hypoxic eIF4F(H). O2-dependent remodeling of translation efficiencies enables cells to produce adaptive translatomes from preexisting mRNA pools. Differences in mRNA expression observed under different [O2] are likely neutral, given that they occur during evolution. We propose that mRNAs contain translation efficiency determinants for their triage by the translation apparatus on [O2] stimulus.

  2. Expert systems for automated maintenance of a Mars oxygen production system

    NASA Technical Reports Server (NTRS)

    Ash, Robert L.; Huang, Jen-Kuang; Ho, Ming-Tsang

    1989-01-01

    A prototype expert system was developed for maintaining autonomous operation of a Mars oxygen production system. Normal operation conditions and failure modes according to certain desired criteria are tested and identified. Several schemes for failure detection and isolation using forward chaining, backward chaining, knowledge-based and rule-based are devised to perform several housekeeping functions. These functions include self-health checkout, an emergency shut down program, fault detection and conventional control activities. An effort was made to derive the dynamic model of the system using Bond-Graph technique in order to develop the model-based failure detection and isolation scheme by estimation method. Finally, computer simulations and experimental results demonstrated the feasibility of the expert system and a preliminary reliability analysis for the oxygen production system is also provided.

  3. System and method for air temperature control in an oxygen transport membrane based reactor

    DOEpatents

    Kelly, Sean M

    2016-09-27

    A system and method for air temperature control in an oxygen transport membrane based reactor is provided. The system and method involves introducing a specific quantity of cooling air or trim air in between stages in a multistage oxygen transport membrane based reactor or furnace to maintain generally consistent surface temperatures of the oxygen transport membrane elements and associated reactors. The associated reactors may include reforming reactors, boilers or process gas heaters.

  4. System and method for temperature control in an oxygen transport membrane based reactor

    DOEpatents

    Kelly, Sean M.

    2017-02-21

    A system and method for temperature control in an oxygen transport membrane based reactor is provided. The system and method involves introducing a specific quantity of cooling air or trim air in between stages in a multistage oxygen transport membrane based reactor or furnace to maintain generally consistent surface temperatures of the oxygen transport membrane elements and associated reactors. The associated reactors may include reforming reactors, boilers or process gas heaters.

  5. Design of high pressure oxygen filter for extravehicular activity life support system, volume 1

    NASA Technical Reports Server (NTRS)

    Wilson, B. A.

    1977-01-01

    The experience of the National Aeronautics and Space Administration (NASA) with extravehicular activity life support emergency oxygen supply subsystems has shown a large number of problems associated with particulate contamination. These problems have resulted in failures of high pressure oxygen component sealing surfaces. A high pressure oxygen filter was designed which would (a) control the particulate contamination level in the oxygen system to a five-micron glass bead rating, ten-micron absolute condition (b) withstand the dynamic shock condition resulting from the sudden opening of 8000 psi oxygen system shutoff valve. Results of the following program tasks are reported: (1) contaminant source identification tests, (2) dynamic system tests, (3) high pressure oxygen filter concept evaluation, (4) design, (5) fabrication, (6) test, and (7) application demonstration.

  6. An Inexpensive Electrode and Cell for Measurement of Oxygen Uptake in Chemical and Biochemical Systems.

    ERIC Educational Resources Information Center

    Brunet, Juan E.; And Others

    1983-01-01

    The continuous measurement of oxygen consumption in an enzymatic reaction is a frequent experimental fact and extremely important in the enzymatic activity of oxygenase. An electrochemical system, based on a polarographic method, has been developed to monitor the oxygen uptake. The system developed and electrode used are described. (JN)

  7. Activation of molecular oxygen by infrared laser radiation in pigment-free aerobic systems.

    PubMed

    Krasnovsky, A A; Drozdova, N N; Ivanov, A V; Ambartsumian, R V

    2003-09-01

    With the goal of mimicking the mechanisms of the biological effects of low energy laser irradiation, we have shown that infrared low intensity laser radiation causes oxygenation of the chemical traps of singlet oxygen dissolved in organic media and water saturated by air at normal atmospheric pressure. The photooxygenation rate was directly proportional to the oxygen concentration and strongly inhibited by the singlet oxygen quenchers. The maximum of the photooxygenation action spectrum coincided with the maximum of the oxygen absorption band at 1270 nm. The data provide unambiguous evidence that photooxygenation is determined by the reactive singlet (1)Delta(g )state formed as a result of direct laser excitation of molecular oxygen. Hence, activation of oxygen caused by its direct photoexcitation may occur in natural systems.

  8. Development of a Solid Chlorate Backup Oxygen Delivery System for the International Space Station

    NASA Technical Reports Server (NTRS)

    Graf, John; Dunlap, Cameron; Haas, Jon; Weislogel, Mark; Lewis, John; Meyers, Karen; McKernan, Andrew

    2000-01-01

    The International Space Station (ISS) Program requires that there always be a 45 calendar day contingency supply of breathing oxygen. In the early assembly stages, there is only one flight system, the Russian Solid Fuel Oxygen Generator (SFOG), that can meet that requirement. To better ensure the contingency oxygen supply, the Crew and Thermal Systems Division was directed to develop a flight hardware system that can meet all contingency oxygen requirements for ISS. Such a system, called the Backup Oxygen Candle System (BOCS), has been built and tested. The BOCS consists of 33 chlorate candles, a thermal containment apparatus, support equipment and packaging. The thermal containment apparatus utilizes the O2 produced by the candle as the motive stream in an ejector to passively cool the candle during operation.

  9. Evaluating systems for oxygen service through the use of quantitative fault tree analysis

    NASA Astrophysics Data System (ADS)

    Santay, Anthony J.

    In the event of a process plant upset, systems not normally intended for use in oxygen service may be suddenly subject to an oxygen-enriched atmosphere. If the upset condition occurs frequently, a conservative approach would be to design all components as if they were normally in oxygen service. As an alternative, one could calculate the probability of the upset condition to quantitatively assess the risk and recommend corrective measures to further reduce the risk. Quantified fault tree techniques are used to determine a system's compatibility when exposed to oxygen in this manner.

  10. Hydrogen sulfide and oxygen sensing in the cardiovascular system.

    PubMed

    Olson, Kenneth R; Whitfield, Nathan L

    2010-05-15

    Vertebrate cardiorespiratory homeostasis is inextricably dependent upon specialized cells that provide feedback on oxygen status in the tissues, blood, and on occasion, environment. These "oxygen sensing" cells include chemoreceptors and oxygen-sensitive chromaffin cells that initiate cardiorespiratory reflexes, vascular smooth muscle cells that adjust perfusion to metabolism or ventilation, and other cells that condition themselves in response to episodic hypoxia. Identification of how these cells sense oxygen and transduce this into the appropriate physiological response has enormous clinical applicability, but despite intense research there is no consensus regarding the initial hypoxia-effector coupling mechanism. This review examines an alternative mechanism of oxygen sensing using oxidation of endogenously produced hydrogen sulfide (H(2)S) as the O(2)-sensitive couple. Support for this hypothesis includes the similarity of effects of hypoxia and H(2)S on a variety of tissues, augmentation of hypoxic responses by precursors of H(2)S production and their inhibition by inhibitors of H(2)S synthesis, and the rapid consumption of H(2)S by O(2) in the range of intracellular/mitochondrial Po(2). These studies also indicate that, under normoxic conditions, it is doubtful that free H(2)S has longer than a transient existence in tissue or extracellular fluid.

  11. Status of the Node 3 Regenerative Environmental Cpntrol& Life Support System Water Recovery & Oxygen Generation Systems

    NASA Technical Reports Server (NTRS)

    Carrasquillo, Robyn L.

    2003-01-01

    NASA s Marshall Space Flight Center is providing three racks containing regenerative water recovery and oxygen generation systems (WRS and OGS) for flight on the lnternational Space Station s (ISS) Node 3 element. The major assemblies included in these racks are the Water Processor Assembly (WPA), Urine Processor Assembly (UPA), Oxygen Generation Assembly (OGA), and the Power Supply Module (PSM) supporting the OGA. The WPA and OGA are provided by Hamilton Sundstrand Space Systems lnternational (HSSSI), while the UPA and PSM are being designed and manufactured in-house by MSFC. The assemblies are currently in the manufacturing and test phase and are to be completed and integrated into flight racks this year. This paper gives an overview of the technologies and system designs, technical challenges encountered and solved, and the current status.

  12. Evaluation of oxygen-enrichment system for alternative fuel vehicles

    SciTech Connect

    Poola, R.B.; Sekar, R.R.; Ng, H.K.

    1995-12-01

    This report presents results on the reduction in exhaust emissions achieved by using oxygen-enriched intake air on a flexible fuel vehicle (FFV) that used Indolene and M85 as test fuels. The standard federal test procedure (FTP) and the US Environmental Protection Agency`s (EPA`s) off-cycle (REP05) test were followed. The report also provides a review of literature on the oxygen membrane device and design considerations. It presents information on the sources and contributions of cold-phase emissions to the overall exhaust emissions from light-duty vehicles (LDVs) and on the various emission standards and present-day control technologies under consideration. The effects of oxygen-enriched intake air on FTP and off-cycle emissions are discussed on the basis of test results. Conclusions are drawn from the results and discussion, and different approaches for the practical application of this technology in LDVs are recommended.

  13. Nonintrusive fast response oxygen monitoring system for high temperature flows

    NASA Technical Reports Server (NTRS)

    Oh, Daniel B.; Stanton, Alan C.

    1993-01-01

    A new technique has been developed for nonintrusive in situ measurement of oxygen concentration, gas temperature, and flow velocity of the test media in hypersonic wind tunnels. It is based on absorption of near-infrared radiation from inexpensive GaAlAs laser diodes used in optoelectronics industry. It is designed for simultaneous measurements along multiple lines of sight accessed by fiber optics. Molecular oxygen concentration is measured from the magnitude of absorption signals; rotational gas temperature is measured from the intensity ratio of two oxygen absorption lines; and the flow velocity is measured from the Doppler shift of the absorption line positions. This report describes the results of an extensive series of tests of the prototype instrument in laboratory flames emphasizing assessment of the instruments capabilities for quantitative measurement of O2 concentration (mole fraction) and gas temperature.

  14. System for measuring oxygen consumption rates of mammalian cells in static culture under hypoxic conditions.

    PubMed

    Kagawa, Yuki; Miyahara, Hirotaka; Ota, Yuri; Tsuneda, Satoshi

    2016-01-01

    Estimating the oxygen consumption rates (OCRs) of mammalian cells in hypoxic environments is essential for designing and developing a three-dimensional (3-D) cell culture system. However, OCR measurements under hypoxic conditions are infrequently reported in the literature. Here, we developed a system for measuring OCRs at low oxygen levels. The system injects nitrogen gas into the environment and measures the oxygen concentration by an optical oxygen microsensor that consumes no oxygen. The developed system was applied to HepG2 cells in static culture. Specifically, we measured the spatial profiles of the local dissolved oxygen concentration in the medium, then estimated the OCRs of the cells. The OCRs, and also the pericellular oxygen concentrations, decreased nonlinearly as the oxygen partial pressure in the environment decreased from 19% to 1%. The OCRs also depended on the culture period and the matrix used for coating the dish surface. Using this system, we can precisely estimate the OCRs of various cell types under environments that mimic 3-D culture conditions, contributing crucial data for an efficient 3-D culture system design.

  15. Stabilization of the yeast desaturase system by low levels of oxygen

    NASA Technical Reports Server (NTRS)

    Volkmann, C. M.; Klein, H. P.

    1983-01-01

    The stability of particulate palmitoyl-CoA desaturase preparations from anaerobically grown yeast cells was increased by exposure to low levels of oxygen. The stabilizing effect of oxygen may be based upon the increased amounts of palmitoleic acid and ergosterol that become available to the cells. These results suggest the evolutinary appearance of this system at a time when atmospheric oxygen was at a low level.

  16. Analysis of Risks to Oxygen Systems from Particulate and Fiber Contaminants and Derivation of Cleanliness Requirements

    NASA Technical Reports Server (NTRS)

    Lowrey, Nikki M.

    2016-01-01

    It has been well documented in the literature that contamination within oxygen systems can create significant fire hazards. Cleanliness limits for nonvolatile residues, ranging from 10 to 500 mg/sq m, have been established for various industries and types of oxygen systems to reduce the risk of ignition of flammable organic films. Particulate cleanliness limits used for oxygen systems vary considerably. Maximum allowed particle size, quantity limits, and allocations for fibers or metallic particles are all variables seen in aerospace cleanliness limits. Particles are known to have the potential to ignite within oxygen systems and must be limited to prevent fires. Particulate contamination may also pose risks to the performance of oxygen systems that are unrelated to ignition hazards. An extensive literature search was performed to better understand the relative importance of particle ignition mechanisms versus other deleterious effects of particles on oxygen systems and to identify rationale for derivation of particulate cleanliness limits for specific systems. The identified risks of different types and sizes of particles and fibers were analyzed. This paper summarizes the risks identified and rationale that may be used to derive particulate cleanliness limits for specific oxygen systems.

  17. Analysis of Risks to Oxygen Systems from Particulate and Fiber Contaminants and Derivation of Cleanliness Requirements

    NASA Technical Reports Server (NTRS)

    Lowrey, Nikki M.

    2016-01-01

    It has been well documented in the literature that contamination within oxygen systems can create significant fire hazards. Cleanliness limits for nonvolatile residues, ranging from 10 to 500 milligrams per square meter, have been established for various industries and types of oxygen systems to reduce the risk of ignition of flammable organic films. Particulate cleanliness limits used for oxygen systems, however, vary considerably, notably within the aerospace industry. Maximum allowed particle size, quantity limits, and allocations for fibers or metallic particles are all variables seen in aerospace cleanliness limits. Particles are known to have the potential to ignite within oxygen systems and must be limited to prevent fires. Particulate contamination may also pose risks to the performance of oxygen systems that are unrelated to ignition hazards. An extensive literature search was performed to better understand the relative importance of particle ignition mechanisms versus other deleterious effects of particles on oxygen systems and to identify rationale for derivation of particulate cleanliness limits for specific systems. The identified risks of different types and sizes of particles and fibers were analyzed. This paper summarizes the risks identified and rationale that may be used to derive particulate cleanliness limits for specific oxygen systems.

  18. Evaluation of Additively Manufactured Metals for Use in Oxygen Systems Project

    NASA Technical Reports Server (NTRS)

    Tylka, Jonathan; Cooper, Ken; Peralta, Stephen; Wilcutt, Terrence; Hughitt, Brian; Generazio, Edward

    2016-01-01

    Space Launch System, Commercial Resupply, and Commercial Crew programs have published intent to use additively manufactured (AM) components in propulsion systems and are likely to include various life support systems in the future. Parts produced by these types of additive manufacturing techniques have not been fully evaluated for use in oxygen systems and the inherent risks have not been fully identified. Some areas of primary concern in the SLS process with respect to oxygen compatibility may be the porosity of the printed parts, fundamental differences in microstructure of an AM part as compared to traditional materials, or increased risk of shed metal particulate into an oxygen system. If an ignition were to occur the printed material could be more flammable than components manufactured from a traditional billet of raw material and/or present a significant hazards if not identified and rigorously studied in advance of implementation into an oxygen system.

  19. Oxygen transport as a structure probe for heterogeneous polymeric systems

    NASA Astrophysics Data System (ADS)

    Hu, Yushan

    Although permeability of small molecules is often measured as an important performance property, deeper analysis of the transport characteristics provides insight into polymer structure, especially if used in combination with other characterization techniques. Transport of small gas molecules senses the permeable amorphous structure and probes the nature of free volume. This work focuses on oxygen transport, supplemented with other methods of physical analysis, as a probe for: (1) the nature of free volume and crystalline morphology in the crystallized glassy state, (2) the nature of free volume and hierarchical structure in liquid crystalline polymers, and (3) the role of dispersed polyamide phase geometry on oxygen barrier properties of poly(ethylene terephthalate) (PET)/polyamide blends. In the first part, the improvement in oxygen-barrier properties of glassy polyesters by crystallization was examined. Examples included poly(ethylene naphthalate) (PEN), and a copolymer based on PET in which 55 mol% terephthalate was replaced with 4,4'-bibenzoate. Explanation of the unexpectedly high solubility of crystallized PEN required a two-phase transport model consisting of an impermeable crystalline phase of constant density and a permeable amorphous phase of variable density. The resulting relationship between oxygen solubility and amorphous phase density was consistent with free volume concepts of gas sorption. In the second part, oxygen barrier properties of liquid crystalline (LC) polyesters based on poly(diethylene glycol 4,4'-bibenzoate) (PDEGBB) were studied. This study extended the 2-phase transport model for oxygen transport of non-LC crystalline polymers to a smectic LCP. It was possible to systematically vary the solid state structure of (PDEGBB) from LC glass to crystallized LC glass. The results were consistent with a liquid crystalline state intermediate between the permeable amorphous glass and the impermeable 3-dimensional crystal. In this interpretation

  20. Solid-Phase Equilibria for Metal-Silicon-Oxygen Ternary Systems. II. Sc, Y, and La

    DTIC Science & Technology

    1991-02-28

    Organization: Regents of the University of California TECHNICAL REPORT No. 9 SOLID- PHASE EQUILIBRIA FOR METAL-SILICON-OXYGEN TERNARY SYSTEMS: 11: Sc, Y, AND La...34’ SOLID- PHASE EQUILIBRIA FOR METAL-SILICON-OXYGEN TERNARY SYSTEMS: 11: Sc, Y, AND 1a 13 0911OtiA AUTHORCS) Haojie Yuan and R. Stanley Williams lI" TV...0660te tCLhSSWI=) Solid phase equilibria for metal-silicon-oxygen ternary systems I1: Sc, Y and La Haojie Yuan and R. Stanley Williams Department of

  1. Atomic Oxygen Durability Evaluation of Protected Polymers Using Thermal Energy Plasma Systems

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Rutledge, Sharon K.; Degroh, Kim K.; Stidham, Curtis R.; Gebauer, Linda; Lamoreaux, Cynthia M.

    1995-01-01

    The durability evaluation of protected polymers intended for use in low Earth orbit (LEO) has necessitated the use of large-area, high-fluence, atomic oxygen exposure systems. Two thermal energy atomic oxygen exposure systems which are frequently used for such evaluations are radio frequency (RF) plasma ashers and electron cyclotron resonance plasma sources. Plasma source testing practices such as ample preparation, effective fluence prediction, atomic oxygen flux determination, erosion measurement, operational considerations, and erosion yield measurements are presented. Issues which influence the prediction of in-space durability based on ground laboratory thermal energy plasma system testing are also addressed.

  2. NASA Rocket Propulsion Test Replacement Effort for Oxygen System Cleaner - Hydrochlorofluorocarbon (HCFC) 225

    NASA Technical Reports Server (NTRS)

    DeWitt Burns, H.; Mitchell, Mark A.; Lowrey, Nikki M.; Farner, Bruce R.; Ross, H. Richard

    2014-01-01

    Gaseous and liquid oxygen are extremely reactive materials used in bipropellant propulsion systems. Both flight and ground oxygen systems require a high level of cleanliness to support engine performance, testing, and prevent mishaps. Solvents used to clean and verify the cleanliness of oxygen systems and supporting test hardware must be compatible with the system's materials of construction and effective at removing or reducing expected contaminants to an acceptable level. This paper will define the philosophy and test approach used for evaluating replacement solvents for the current Marshall Space Flight Center/Stennis Space Center baseline HCFC-225 material that will no longer be available for purchase after 2014. MSFC/SSC applications in cleaning / sampling oxygen propulsion components, support equipment, and test system were reviewed then candidate replacement cleaners and test methods selected. All of these factors as well as testing results will be discussed.

  3. 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...

  4. Onboard Inert Gas Generation System/Onboard Oxygen Gas Generation System (OBIGGS/OBOGS) Study. Part 1; Aircraft System Requirements

    NASA Technical Reports Server (NTRS)

    Reynolds, Thomas L.; Bailey, Delbert B.; Lewinski, Daniel F.; Roseburg, Conrad M.; Palaszewski, Bryan (Technical Monitor)

    2001-01-01

    The purpose of this technology assessment is to define a multiphase research study program investigating Onboard Inert Gas Generation Systems (OBIGGS) and Onboard Oxygen Generation Systems (OBOGS) that would identify current airplane systems design and certification requirements (Subtask 1); explore state-of-the-art technology (Subtask 2); develop systems specifications (Subtask 3); and develop an initial system design (Subtask 4). If feasible, consideration may be given to the development of a prototype laboratory test system that could potentially be used in commercial transport aircraft (Subtask 5). These systems should be capable of providing inert nitrogen gas for improved fire cargo compartment fire suppression and fuel tank inerting and emergency oxygen for crew and passenger use. Subtask I of this research study, presented herein, defines current production aircraft certification requirements and design objectives necessary to meet mandatory FAA certification requirements and Boeing design and performance specifications. These requirements will be utilized for baseline comparisons for subsequent OBIGGS/OBOGS application evaluations and assessments.

  5. Cerebral venous blood oxygenation monitoring during hyperventilation in healthy volunteers with a novel optoacoustic system

    NASA Astrophysics Data System (ADS)

    Petrov, Andrey; Prough, Donald S.; Petrov, Irene Y.; Petrov, Yuriy; Deyo, Donald J.; Henkel, Sheryl N.; Seeton, Roger; Esenaliev, Rinat O.

    2013-03-01

    Monitoring of cerebral venous oxygenation is useful to facilitate management of patients with severe or moderate traumatic brain injury (TBI). Prompt recognition of low cerebral venous oxygenation is a key to avoiding secondary brain injury associated with brain hypoxia. In specialized clinical research centers, jugular venous bulb catheters have been used for cerebral venous oxygenation monitoring and have demonstrated that oxygen saturation < 50% (normal range is 55-75%) correlates with poor clinical outcome. We developed an optoacoustic technique for noninvasive monitoring of cerebral venous oxygenation. Recently, we designed and built a novel, medical grade optoacoustic system operating in the near-infrared spectral range for continuous, real-time oxygenation monitoring in the superior sagittal sinus (SSS), a large central cerebral vein. In this work, we designed and built a novel SSS optoacoustic probe and developed a new algorithm for SSS oxygenation measurement. The SSS signals were measured in healthy volunteers during voluntary hyperventilation, which induced changes in SSS oxygenation. Simultaneously, we measured exhaled carbon dioxide concentration (EtCO2) using capnography. Good temporal correlation between decreases in optoacoustically measured SSS oxygenation and decreases in EtCO2 was obtained. Decreases in EtCO2 from normal values (35-45 mmHg) to 20-25 mmHg resulted in SSS oxygenation decreases by 3-10%. Intersubject variability of the responses may relate to nonspecific brain activation associated with voluntary hyperventilation. The obtained data demonstrate the capability of the optoacoustic system to detect in real time minor changes in the SSS blood oxygenation.

  6. Two-level multivariable control system of dissolved oxygen tracking and aeration system for activated sludge processes.

    PubMed

    Piotrowski, Robert

    2015-01-01

    The problem of tracking dissolved oxygen is one of the most complex and fundamental issues related to biological processes. The dissolved oxygen level in aerobic tanks has a significant influence on the behavior and activity of microorganisms. Aerated tanks are supplied with air from an aeration system (blowers, pipes, throttling valves, and diffusers). It is a complex, dynamic system governed by nonlinear hybrid dynamics. Control of the aeration system is also difficult in terms of control of the dissolved oxygen. In this article, a two-level multivariable control system for tracking dissolved oxygen and controlling an aeration system is designed. A nonlinear model predictive control algorithm was applied to design controllers for each level. This overall hierarchical control system was validated by simulation based on real data records provided by a water resource recovery facility located in Kartuzy, Northern Poland. The effect of control system parameters and disturbances was also investigated.

  7. Expert systems for automated maintenance of a Mars oxygen production system

    NASA Astrophysics Data System (ADS)

    Huang, Jen-Kuang; Ho, Ming-Tsang; Ash, Robert L.

    1992-08-01

    Application of expert system concepts to a breadboard Mars oxygen processor unit have been studied and tested. The research was directed toward developing the methodology required to enable autonomous operation and control of these simple chemical processors at Mars. Failure detection and isolation was the key area of concern, and schemes using forward chaining, backward chaining, knowledge-based expert systems, and rule-based expert systems were examined. Tests and simulations were conducted that investigated self-health checkout, emergency shutdown, and fault detection, in addition to normal control activities. A dynamic system model was developed using the Bond-Graph technique. The dynamic model agreed well with tests involving sudden reductions in throughput. However, nonlinear effects were observed during tests that incorporated step function increases in flow variables. Computer simulations and experiments have demonstrated the feasibility of expert systems utilizing rule-based diagnosis and decision-making algorithms.

  8. The Search for Nonflammable Solvent Alternatives for Cleaning Aerospace Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Mitchell, Mark A.; Lowrey, Nikki

    2012-01-01

    To obtain a high degree of cleanliness without risk of corrosion or hazardous reactivity, hydrochlorofluorocarbon (HCFC)-225 is used for cleaning and cleanliness verification of oxygen system components used on NASA fs bipropellant launch vehicles, associated test stands and support equipment. HCFC-225 is a Class II Ozone Depleting Substance (ODS ]II) that was introduced to replace chlorofluorocarbon (CFC)-113, a Class I ODS solvent that is now banned. To meet environmental regulations to eliminate the use of ozone depleting substances, a replacement solvent is required for HCFC ]225 that is effective at removing oils, greases, and particulate from large oxygen system components, is compatible with materials used in the construction of these systems, and is nonflammable and non ]reactive in enriched oxygen environments. A solvent replacement is also required for aviator fs breathing oxygen systems and other related equipment currently cleaned and verified with HCFC ]225 and stockpiled CFC -113. Requirements and challenges in the search for nonflammable replacement solvents are discussed.

  9. Phase diagram of the Pr-Mn-O system in composition-temperature-oxygen pressure coordinates

    NASA Astrophysics Data System (ADS)

    Vedmid', L. B.; Yankin, A. M.; Fedorova, O. M.; Kozin, V. M.

    2016-05-01

    The phase relations in the Pr-Mn-O system were studied by the static method at lowered oxygen pressure in combination with thermal analysis and high-temperature X-ray diffraction. The equilibrium oxygen pressure in dissociation of PrMn2O5 and PrMnO3 was measured, and the thermodynamic characteristics of formation of these compounds from elements were calculated. The P- T- x phase diagram of the Pr-Mn-O system was constructed in the "composition-oxygen pressure-temperature" coordinates.

  10. The Thermodynamics of Thorium-Oxygen and Uranium-Oxygen Systems

    DTIC Science & Technology

    1975-02-19

    i 2 Thermodynamic functions for UO2 (g) .................- 15 3 Thermodynamic functions for TlO(g) --------- ---- - - - -- 25 4 Thermodynamic...The vapor above uranium oxide condensed phases includes U, 110, 蓥 and U03* The composition of the vapor is strongly dependent upon theL0 ratio. In...the three phase system U(L)/U02(s) and vapor (O/U < 1.7) the principal vapor phlast species is UO with smaller amounts of U and to2 vapors. For UO2 a

  11. Hydrogen and Oxygen Gas Monitoring System Design and Operation

    SciTech Connect

    Lee C. Cadwallader; Kevin G. DeWall; J. Stephen Herring

    2007-06-01

    This paper describes pertinent design practices of selecting types of monitors, monitor unit placement, setpoint selection, and maintenance considerations for gas monitors. While hydrogen gas monitors and enriched oxygen atmosphere monitors as they would be needed for hydrogen production experiments are the primary focus of this paper, monitors for carbon monoxide and carbon dioxide are also discussed. The experiences of designing, installing, and calibrating gas monitors for a laboratory where experiments in support of the DOE Nuclear Hydrogen Initiative (NHI) are described along with codes, standards, and regulations for these monitors. Information from the literature about best operating practices is also presented. The NHI program has two types of activities. The first, near-term activity is laboratory and pilot-plant experimentation with different processes in the kilogram per day scale to select the most promising types of processes for future applications of hydrogen production. Prudent design calls for indoor gas monitors to sense any hydrogen leaks within these laboratory rooms. The second, longer-term activity is the prototype, or large-scale plants to produce tons of hydrogen per day. These large, outdoor production plants will require area (or “fencepost”) monitoring of hydrogen gas leaks. Some processes will have oxygen production with hydrogen production, and any oxygen releases are also safety concerns since oxygen gas is the strongest oxidizer. Monitoring of these gases is important for personnel safety of both indoor and outdoor experiments. There is some guidance available about proper placement of monitors. The fixed point, stationary monitor can only function if the intruding gas contacts the monitor. Therefore, monitor placement is vital to proper monitoring of the room or area. Factors in sensor location selection include: indoor or outdoor site, the location and nature of potential vapor/gas sources, chemical and physical data of the

  12. Estimation of biological oxygen demand and chemical oxygen demand for combined sewer systems using synchronous fluorescence spectra.

    PubMed

    Hur, Jin; Lee, Bo-Mi; Lee, Tae-Hwan; Park, Dae-Hee

    2010-01-01

    Real-time monitoring of water quality for sewer system is required for efficient sewer network design because it provides information on the precise loading of pollutant to wastewater treatment facilities and the impact of loading on receiving water. In this study, synchronous fluorescence spectra and its first derivatives were investigated using a number of wastewater samples collected in sewer systems in urban and non-urban areas, and the optimum fluorescence feature was explored for the estimation of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) concentrations of sewer samples. The temporal variations in BOD and COD showed a regular pattern for urban areas whereas they were relatively irregular for non-urban areas. Irrespective of the sewer pipes and the types of the areas, two distinct peaks were identified from the synchronous fluorescence spectra, which correspond to protein-like fluorescence (PLF) and humic-like fluorescence (HLF), respectively. HLF in sewer samples appears to be associated with fluorescent whitening agents. Five fluorescence characteristics were selected from the synchronous spectra and the first-derivatives. Among the selected fluorescence indices, a peak in the PLF region (i.e., Index I) showed the highest correlation coefficient with both BOD and COD. A multiple regression approach based on suspended solid (SS) and Index I used to compensate for the contribution of SS to BOD and COD revealed an improvement in the estimation capability, showing good correlation coefficients of 0.92 and 0.94 for BOD and COD, respectively.

  13. The Search for Nonflammable Solvent Alternatives for Cleaning Aerospace Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Mitchell, Mark; Lowrey, Nikki

    2012-01-01

    Oxygen systems are susceptible to fires caused by particle and nonvolatile residue (NVR) contaminants, therefore cleaning and verification is essential for system safety. . Cleaning solvents used on oxygen system components must be either nonflammable in pure oxygen or complete removal must be assured for system safety. . CFC -113 was the solvent of choice before 1996 because it was effective, least toxic, compatible with most materials of construction, and non ]reactive with oxygen. When CFC -113 was phased out in 1996, HCFC -225 was selected as an interim replacement for cleaning propulsion oxygen systems at NASA. HCFC-225 production phase-out date is 01/01/2015. HCFC ]225 (AK ]225G) is used extensively at Marshall Space Flight Center and Stennis Space Center for cleaning and NVR verification on large propulsion oxygen systems, and propulsion test stands and ground support equipment. . Many components are too large for ultrasonic agitation - necessary for effective aqueous cleaning and NVR sampling. . Test stand equipment must be cleaned prior to installation of test hardware. Many items must be cleaned by wipe or flush in situ where complete removal of a flammable solvent cannot be assured. The search for a replacement solvent for these applications is ongoing.

  14. Hemolytic and thrombocytopathic characteristics of extracorporeal membrane oxygenation systems at simulated flow rate for neonates*

    PubMed Central

    Meyer, Andrew D.; Wiles, Andrew A.; Rivera, Oswaldo; Wong, Edward C.; Freishtat, Robert J.; Rais-Bahrami, Khoydar; Dalton, Heidi J.

    2012-01-01

    Objective A state-of-the-art centrifugal pump combined with hollow-fiber oxygenator for extracorporeal membrane oxygenation has potential advantages such as smaller priming volumes and decreased potential to cause tubing rupture as compared with the traditional roller head/silicone membrane systems. Adoption of these state-of-the-art systems has been slow in neonates as a result of past evidence of severe hemolysis that may lead to renal failure and increased mortality. Extracorporeal systems have also been linked to platelet dysfunction, a contributing factor toward intracranial hemorrhage, a leading cause of infant morbidity. Little data exist comparing the centrifugal systems with the roller systems in terms of hemolysis and platelet aggregation at low flow rates commonly used in neonatal extracorporeal membrane oxygenation. Design Prospective, comparative laboratory study. Setting University research laboratory. Subjects Centrifugal pump, roller pump, hollow-fiber oxygenator, and silicone membrane oxygenator. Interventions Comparative study using two pumps, the centrifugal Jostra Rotaflow (Maquet, Wayne, NJ) and the roller-head (Jostra, Maquet, Wayne, NJ), and two oxygenators, polymethly-pentene Quadrox-D (Maquet) and silicone membrane (Medtronic, Minneapolis, MN). Five test runs of four circuit combinations were examined for hemolysis and platelet aggregation during 6 hrs of continuous use in a simulated in vitro extracorporeal membrane oxygenation circuit circulating whole swine blood at 300 mL/min. Measurements and Main Results Hemolysis was assessed by spectrophometric measurement of plasma-free hemoglobin. Platelet aggregation was evaluated using monoclonal CD61 antibody fluorescent flow cytometry profiles. All of the extracorporeal membrane oxygenation systems created plasma-free hemoglobin at a similar rate compared with static blood control. There was no difference in the mean normalized index of hemolysis of the centrifugal/hollow-fiber oxygenator

  15. First-in-human pilot study of a spatial frequency domain oxygenation imaging system

    NASA Astrophysics Data System (ADS)

    Gioux, Sylvain; Mazhar, Amaan; Lee, Bernard T.; Lin, Samuel J.; Tobias, Adam M.; Cuccia, David J.; Stockdale, Alan; Oketokoun, Rafiou; Ashitate, Yoshitomo; Kelly, Edward; Weinmann, Maxwell; Durr, Nicholas J.; Moffitt, Lorissa A.; Durkin, Anthony J.; Tromberg, Bruce J.; Frangioni, John V.

    2011-08-01

    Oxygenation measurements are widely used in patient care. However, most clinically available instruments currently consist of contact probes that only provide global monitoring of the patient (e.g., pulse oximetry probes) or local monitoring of small areas (e.g., spectroscopy-based probes). Visualization of oxygenation over large areas of tissue, without a priori knowledge of the location of defects, has the potential to improve patient management in many surgical and critical care applications. In this study, we present a clinically compatible multispectral spatial frequency domain imaging (SFDI) system optimized for surgical oxygenation imaging. This system was used to image tissue oxygenation over a large area (16×12 cm) and was validated during preclinical studies by comparing results obtained with an FDA-approved clinical oxygenation probe. Skin flap, bowel, and liver vascular occlusion experiments were performed on Yorkshire pigs and demonstrated that over the course of the experiment, relative changes in oxygen saturation measured using SFDI had an accuracy within 10% of those made using the FDA-approved device. Finally, the new SFDI system was translated to the clinic in a first-in-human pilot study that imaged skin flap oxygenation during reconstructive breast surgery. Overall, this study lays the foundation for clinical translation of endogenous contrast imaging using SFDI.

  16. Biradical vs singlet oxygen photogeneration in suprofen–cholesterol systems

    PubMed Central

    Palumbo, Fabrizio; Bosca, Francisco; Morera, Isabel Maria

    2016-01-01

    Summary Cholesterol (Ch) is an important lipidic building block and a target for oxidative degradation, which can be induced via free radicals or singlet oxygen (1O2). Suprofen (SP) is a nonsteroidal anti-inflammatory drug that contains the 2-benzoylthiophene (BZT) chromophore and has a π,π* lowest triplet excited state. In the present work, dyads (S)- and (R)-SP-α-Ch (1 and 2), as well as (S)-SP-β-Ch (3) have been prepared from β- or α-Ch and SP to investigate the possible competition between photogeneration of biradicals and 1O2, the key mechanistic steps in Ch photooxidation. Steady-state irradiation of 1 and 2 was performed in dichloromethane, under nitrogen, through Pyrex, using a 400 W medium pressure mercury lamp. The spectral analysis of the separated fractions revealed formation of two photoproducts 4 and 5, respectively. By contrast, under the same conditions, 3 did not give rise to any isolable Ch-derived product. These results point to an intramolecular hydrogen abstraction in 1 and 2 from the C7 position of Ch and subsequent C–C coupling of the generated biradicals. Interestingly, 2 was significantly more photoreactive than 1 indicating a clear stereodifferentiation in the photochemical behavior. Transient absorption spectra obtained for 1–3 were very similar and matched that described for the SP triplet excited state (typical bands with maxima at ca. 350 nm and 600 nm). Direct kinetic analysis of the decay traces at 620 nm led to determination of triplet lifetimes that were ca. 4.1 μs for 1 and 2 and 5.8 μs for 3. From these data, the intramolecular quenching rate constants in 1 and 2 were determined as 0.78 × 105 s−1. The capability of dyads 1–3 to photosensitize the production of singlet oxygen was assessed by time-resolved near infrared emission studies in dichloromethane using perinaphthenone as standard. The quantum yields (ΦΔ) were 0.52 for 1 and 2 and 0.56 for 3. In conclusion, SP-α-Ch dyads are unique in the sense that they

  17. Oxygen enrichment and its application to life support systems for workers in high-altitude areas

    PubMed Central

    Li, Yongling; Liu, Yingshu

    2014-01-01

    Background: Workers coming from lowland regions are at risk of developing acute mountain sickness (AMS) when working in low oxygen high-altitude areas. Objectives: The aim of this study was to improve the conditions that lead to hypoxia and ensure the safety of the high-altitude workers. We analyzed the influence of low atmospheric pressure on the oxygen enrichment process in high-altitude areas using an engineering method called low-pressure swing adsorption (LPSA). Methods: Fourteen male subjects were screened and divided into three groups by type of oxygen supply system used: (1) oxygen cylinder group; (2) LPSA oxygen dispersal group; and (3) control group. These tests included arterial oxygen saturation (SaO2), pulse rate (PR), breaths per minute (BPM), and blood pressure (BP). Results: The results showed that after supplying oxygen using the LPSA method at the tunnel face, the SaO2 of workers increased; the incidence of acute mountain sickness, PR, and BPM significantly decreased. Conclusions: The LPSA life support system was found to be a simple, convenient, efficient, reliable, and applicable approach to ensure proper working conditions at construction sites in high-altitude areas. PMID:25000108

  18. Molecular sieve generation of aviator's oxygen: Performance of a prototype system under simulated flight conditions.

    PubMed

    Miller, R L; Ikels, K G; Lamb, M J; Boscola, E J; Ferguson, R H

    1980-07-01

    The molecular sieve method of generating an enriched-oxygen breathing gas is one of several candidate onboard oxygen generation (OBOG) systems under joint Army-Navy-Air Force development for application in tactical aircraft. The performance of a nominal two-man-capacity molecular sieve oxygen generation system was characterized under simulated flight conditions. Data are given on the composition of the molecular sieve-generated breathing gas (oxygen, nitrogen, carbon dioxide, and argon) as a function of inlet air pressure, altitude, breathing gas flow rate, and ambient temperature. The maximum oxygen concentration observed was 95%, with the balance argon. At low demand flow rates and certain conditions of pressure and altitude, the argon enrichment factor exceeded that of oxygen giving a maximum argon concentration of 6.6% with the balance oxygen. The structural integrity of the unit was verified by vibration and centrifuge testing. The performance of the molecular sieve unit is discussed in the context of aircraft operating envelopes using both diluter-demand and 100% delivery subsystems.

  19. An evaluation of a micro programmable logic controller for oxygen monitoring and control in tanks of a recirculating aquaculture system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Control of dissolved gases, especially oxygen is an essential component of recirculating aquaculture systems. The use of pure oxygen in a recirculating aquaculture system creates supersaturated concentrations of dissolved oxygen and can reduce fish production costs by supporting greater fish and fee...

  20. FIELD DEMONSTRATION OF THE LINDE OXYGEN COMBUSTION SYSTEM ON THE EPA MOBILE INCINERATOR

    EPA Science Inventory

    This paper summarizes the various system performance tests and the long-term operating experience of the LINDE Oxygen Combustion System installed on the U.S. Environmental Protection Agency's Mobile Incineration System (MIS) when it was in operation at the Denney Farm site in sou...

  1. A novel Multi-Fiber Optode sensor system (MuFO) for monitoring oxygen

    NASA Astrophysics Data System (ADS)

    Koop-Jakobsen, K.; Fischer, J.; Wenzhöfer, F.

    2012-04-01

    In the marine environment, dissolved oxygen concentrations often vary significantly spatially as well as temporally. Monitoring these variations is essential for our understanding of the biological and chemical processes controlling the oxygen dynamics in water columns and sediments. Such investigations require a high number of measuring points and a high temporal resolution. A Multi-Fiber Optode sensor system (MuFO) was designed to assess these requirements. The MuFO system simultaneously controls 100 fiber optodes enabling continuous monitoring of oxygen in 100 positions within a 5-10m radius. The measurements are based on quenching of an oxygen sensitive luminophore, which is immobilised at the end of each fiber optode. The optical oxygen measurements are based on lifetime-imaging, which are converted into oxygen concentrations using a multipoint calibration. At a constant temperature of 21C, the system overall had a mean accuracy of 1.3%, a precision of 0.2% air saturation, the average 90% response time was 16 seconds and the detection limit was 0.1% air saturation. The MuFO set-up was build into a waterproof titanium casing for marine field applications. The system is battery-powered and has a maximum operational capacity of 15 hours for continuous measurements. The MuFO system was recently used for various research tasks in the marine environment: Mounted on a lander, the in situ MuFO system was used for investigations of oxygen dynamics in marine water columns placing the fiber optodes in a vertical line on a 7m high pole. For studies of oxygen dynamics in marine wetland rhizospheres, the sensing ends of the fiber optodes were covered with a 50cm protective sleeve made from stainless steel tubing, and the sensors were manually pushed into the rhizosphere. For laboratory measurements of sediment oxygen demand, the MuFO system was used to simultaneously monitor the oxygen consumption in multiple sediment slurry incubations. The MuFO system proved to be a

  2. Oxygen dependence of the reduction of nitroimidazoles in a radiolytic model system

    SciTech Connect

    Rauth, A.M.; McClelland, R.A.; Michaels, H.B.; Battistella, R.

    1984-08-01

    Radiation chemical reductions using e/sub aq//sup -/ and CO/sub 2//sup -/ have been carried out in the presence of oxygen with metronidazole, p-nitroacetophenone, misonidazole and three other 2-nitroimidazoles. Low concentrations of oxygen were found to effectively inhibit the reduction of the first two compounds while much higher concentrations of oxygen were required for all of the 2-nitroimidazoles. Kinetic modelling of the radiochemical system suggests that the explanation for the differences lies in different reactions of the nitro radical anions; it appears that the anion derived from metronidazole undergoes disproportionation while that derived from misonidazole undergoes a unimolecular decay.

  3. Biomimetic catalytic system driven by electron transfer for selective oxygenation of hydrocarbon.

    PubMed

    Yang, Guanyu; Ma, Yinfa; Xu, Jie

    2004-09-01

    Hydrocarbon oxyfunctionalization is a crucial industrial process. Most metallic catalysts require higher temperatures and often show lower selectivities. One of the intellectual approaches is the mimicry for bio-oxidation. We have established a biomimetic system with a nonmetallic redox center, composed of anthraquinones, N-hydroxyphthalimide, and zeolite HY, for selective hydrocarbon oxygenation by molecular oxygen. Selectivity of 95.8% for acetophenone and 66.2% conversion were accomplished for oxygenation of ethylbenzene at temperatures as low as 80 degrees C. The redox cycle, driven by one-electron transfer and product orientation by Zeolite HY, opens up the possibility of mimicking bio-oxidation under mild conditions.

  4. On-Orbit Checkout and Activation of the ISS Oxygen Generation System

    NASA Technical Reports Server (NTRS)

    Bagdigian, Robert M.; Prokhorov, Kimberlee S.

    2007-01-01

    NASA has developed and; deployed an Oxygen Generation System (OGS) into the Destiny Module of the International Space Station (ISS). The major. assembly; included in this system is the Oxygen Generator Assembly. (OGA) which was developed under NASA contract by Hamilton Sundstrand Space Systems International (HSSSI), Inc. This paper summarizes the installation of the system into the Destiny Module, its initial checkout and periodic preventative maintenance activities, and its operational activation. Trade studies and analyses that were conducted with the goal of mitigating on-orbit operational risks are also discussed.

  5. An upgraded camera-based imaging system for mapping venous blood oxygenation in human skin tissue

    NASA Astrophysics Data System (ADS)

    Li, Jun; Zhang, Xiao; Qiu, Lina; Leotta, Daniel F.

    2016-07-01

    A camera-based imaging system was previously developed for mapping venous blood oxygenation in human skin. However, several limitations were realized in later applications, which could lead to either significant bias in the estimated oxygen saturation value or poor spatial resolution in the map of the oxygen saturation. To overcome these issues, an upgraded system was developed using improved modeling and image processing algorithms. In the modeling, Monte Carlo (MC) simulation was used to verify the effectiveness of the ratio-to-ratio method for semi-infinite and two-layer skin models, and then the relationship between the venous oxygen saturation and the ratio-to-ratio was determined. The improved image processing algorithms included surface curvature correction and motion compensation. The curvature correction is necessary when the imaged skin surface is uneven. The motion compensation is critical for the imaging system because surface motion is inevitable when the venous volume alteration is induced by cuff inflation. In addition to the modeling and image processing algorithms in the upgraded system, a ring light guide was used to achieve perpendicular and uniform incidence of light. Cross-polarization detection was also adopted to suppress surface specular reflection. The upgraded system was applied to mapping of venous oxygen saturation in the palm, opisthenar and forearm of human subjects. The spatial resolution of the oxygenation map achieved is much better than that of the original system. In addition, the mean values of the venous oxygen saturation for the three locations were verified with a commercial near-infrared spectroscopy system and were consistent with previously published data.

  6. Material Usage in High Pressure Oxygen Systems for the International Space Station

    NASA Technical Reports Server (NTRS)

    Kravchenko, Michael; Sievers, D. Elliott

    2014-01-01

    The Nitrogen/Oxygen Recharge System (NORS) for the International Space Station (ISS) Program was required as part of the Space Shuttle retirement efforts to sustain the ISS life support systems. The system is designed around a 7000 psia Oxygen or Nitrogen Recharge Tank Assembly which is able to be utilized both internally and externally to the ISS. Material selection and usage were critical to ensure oxygen compatibility for the design, while taking into consideration toxicity, weldability, brazability and general fabrication and assembly techniques. The system uses unique hardware items such a composite overwrap pressure vessel (COPV), high pressure mechanical gauges, compact regulators and valves, quick disconnects, metal tubing and flexhoses. Numerous challenges and anomalies were encountered due to the exotic nature of this project which will be discussed in detail. The knowledge gained from these anomalies and failure resolutions can be applied to more than space applications, but can also be applicable to industry pressurized systems.

  7. Imaging Reactive Oxygen Species-Induced Modifications in Living Systems

    PubMed Central

    Maulucci, Giuseppe; Bačić, Goran; Bridal, Lori; Schmidt, Harald H.H.W.; Tavitian, Bertrand; Viel, Thomas; Utsumi, Hideo; Yalçın, A. Süha

    2016-01-01

    Abstract Significance: Reactive Oxygen Species (ROS) may regulate signaling, ion channels, transcription factors, and biosynthetic processes. ROS-related diseases can be due to either a shortage or an excess of ROS. Recent Advances: Since the biological activity of ROS depends on not only concentration but also spatiotemporal distribution, real-time imaging of ROS, possibly in vivo, has become a need for scientists, with potential for clinical translation. New imaging techniques as well as new contrast agents in clinically established modalities were developed in the previous decade. Critical Issues: An ideal imaging technique should determine ROS changes with high spatio-temporal resolution, detect physiologically relevant variations in ROS concentration, and provide specificity toward different redox couples. Furthermore, for in vivo applications, bioavailability of sensors, tissue penetration, and a high signal-to-noise ratio are additional requirements to be satisfied. Future Directions: None of the presented techniques fulfill all requirements for clinical translation. The obvious way forward is to incorporate anatomical and functional imaging into a common hybrid-imaging platform. Antioxid. Redox Signal. 24, 939–958. PMID:27139586

  8. Attrition Rate of Oxygen Carriers in Chemical Looping Combustion Systems

    NASA Astrophysics Data System (ADS)

    Feilen, Harry Martin

    This project developed an evaluation methodology for determining, accurately and rapidly, the attrition resistance of oxygen carrier materials used in chemical looping technologies. Existing test protocols, to evaluate attrition resistance of granular materials, are conducted under non-reactive and ambient temperature conditions. They do not accurately reflect the actual behavior under the unique process conditions of chemical looping, including high temperatures and cyclic operation between oxidizing and reducing atmospheres. This project developed a test method and equipment that represented a significant improvement over existing protocols. Experimental results obtained from this project have shown that hematite exhibits different modes of attrition, including both due to mechanical stresses and due to structural changes in the particles due to chemical reaction at high temperature. The test methodology has also proven effective in providing reactivity changes of the material with continued use, a property, which in addition to attrition, determines material life. Consumption/replacement cost due to attrition or loss of reactivity is a critical factor in the economic application of the chemical looping technology. This test method will allow rapid evaluation of a wide range of materials that are best suited for this technology. The most important anticipated public benefit of this project is the acceleration of the development of chemical looping technology for lowering greenhouse gas emissions from fossil fuel combustion.

  9. Oxygen/hydrogen Space Station propulsion system concept definition for IOC

    NASA Technical Reports Server (NTRS)

    Shoji, J. M.; Meisl, C. J.; Glass, J. F.; Tu, W.-H.; Ebert, S. J.; Evans, S. A.; Jones, L. W.; Campbell, H.

    1986-01-01

    The potential for the reduction in propulsion system life cycle costs through the use of on-board water electrolysis to generate oxygen and hydrogen propellants, as well as the potential advantages of improved system safety and contamination impact, led to a study to evaluate candidate oxygen-/hydrogen-based propulsion systems. In this study a representative set of propulsion system requirements were compiled and candidate oxygen/hydrogen-based propulsion systems synthesized. These candidate concepts were screened and a systems evaluation was performed on the remaining eight candidate concepts. Detailed system schematics were prepared. Operational design conditions were determined and system weight, volume, energy requirements, and costs were calculated. Evaluation results indicated that the oxygen/hydrogen propulsion systems can provide simple, low cost, and viable systems for the IOC Space Station. Based on these data, a relative concept evaluation was conducted using as selection criteria reliability, safety, cost, technical risk, contamination, operational utility, growth potential, and integration potential. Top ranked candidate systems were recommended to NASA/MSFC for consideration for the IOC Space Station.

  10. Reliability of the Gas Supply in the Air Force Emergency Passenger Oxygen System

    DTIC Science & Technology

    2005-10-01

    to be intact. A hypodermic needle was attached to the sampling line of a mass spectrometer (Perkin-El- mer, Model MGA-1100). The needle was inserted...Emergency Passenger Oxygen System (EPOS; Fig. 1) was alleged to have significant numbers of inadequate oxygen cylinders. In theory , this could prevent the...hypothetical analysis demonstrates the disparity between a manufacturing specifi cation of a component and the overall performance of a device. This

  11. Development of 200-channel mapping system for tissue oxygenation measured by near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Niwayama, Masatsugu; Kohata, Daisuke; Shao, Jun; Kudo, Nobuki; Hamaoka, Takatumi; Katsumura, Toshihito; Yamamoto, Katsuyuki

    2000-07-01

    Near-infrared spectroscopy (NIRS) is a very useful technique for noninvasive measurement of tissue oxygenation. Among various methods of NIRS, continuous wave near-infrared spectroscopy (CW- NIRS) is especially suitable for real-time measurement and for practical use. CW-NIRS has recently been applied in vivo reflectance imaging of muscle oxygenation and brain activity. However, conventional mapping systems do not have a sufficient mapping area at present. Moreover, they do not enable quantitative measurement of tissue oxygenation because conventional NIRS is based on the inappropriate assumption that tissue is homogeneous. In this study, we developed a 200-channel mapping system that enables measurement of changes in oxygenation and blood volume and that covers a wider area (30 cm x 20 cm) than do conventional systems. The spatial resolution (source- detector separation) of this system is 15 mm. As for the effcts of tissue inhomogeneity on muscle oxygenation measurement, subcutaneous adipose tissue greatly reduces measurement sensitivity. Therefore, we also used a correction method for influence of the subcutaneous fat layer so that we could obtain quantitative changes in concentrations of oxy- and deoxy- hemoglobin. We conducted exercise tests and measured the changed in hemoglobin concentration in the thigh using the new system. The working muscles in the exercises could be imaged, and the heterogeneity of the muscles was shown. These results demonstrated the new 200-channel mapping system enables observation of the distribution of muscle metabolism and localization of muscle function.

  12. Platelet-Derived Microparticles Generated by Neonatal Extracorporeal Membrane Oxygenation Systems

    PubMed Central

    MEyER, ANDREW D.; GELFOND, JONATHAN A.L.; WILES, ANDREW A.; FREISHTAT, ROBERT J.; RAIS-BAHRAMI, KHOYDAR

    2015-01-01

    Current anticoagulation strategies do not eliminate thromboembolic stroke or limb loss during neonatal extracorporeal membrane oxygenation (ECMO), a form of cardiopulmonary bypass (CPB). In adults, CPB surgery generates prothrombotic platelet-derived microparticles (PMPs), submicron membrane vesicles released from activated platelets. However, information on PMP generation in neonatal ECMO systems is lacking. The objective of this study was to compare PMP generation in five different neonatal ECMO systems, using a simulated circuit with swine blood at 300 ml/min for 4 hours. Systems were composed of both newer components (centrifugal pump and hollow-fiber oxygenator) and traditional components (roller-head pump and silicone membrane oxygenator). Free plasma hemoglobin levels were measured as an indicator of hemolysis and flow cytometry-measured PMP. Hemolysis generated in all ECMO systems was similar to that observed in noncirculated static blood (p = 0.48). There was no difference in net PMP levels between different oxygenators with a given pump. In contrast, net PMP generation in ECMO systems with a centrifugal pump was at least 2.5 times greater than in roller-head pump systems. This was significant when using either a hollow-fiber (p < 0.005) or a silicone membrane (p < 0.05) oxygenator. Future studies are needed to define the relationship between pump-generated PMP and thrombosis. PMID:25303795

  13. Chlorophyll Destruction by the Bisulfite-Oxygen System 1

    PubMed Central

    Peiser, Galen D.; Yang, Shang Fa

    1977-01-01

    Destruction of chlorophyll, as determined by the loss in absorbance at 665 nm, occurred in two in vitro systems in the presence of bisulfite in 76% ethanol. The first system required light and O2 in addition to bisulfite and exhibited an optimum pH of 4. Chlorophyll functioned as a photosensitizer and there was little chlorophyll destruction occurring above pH 5. With 286 μeinsteins m−2 irradiation, approximately 80% of the chlorophyll was destroyed in three minutes. In the second system, chlorophyll destruction in the presence of bisulfite occurred in the dark and required Mn2+, O2, and glycine. Destruction of chlorophyll in this system was much more rapid than in the light system with approximately 70% destruction occurring in two seconds. In both systems, chlorophyll destruction was linked to bisulfite oxidation. The free radical scavengers hydroquinone, butylated hydroxytoluene, 1,2-dihydroxybenzene-3,5-disulfonic acid, and α-tocopherol were effective in inhibiting the destruction of chlorophyll in both systems. The singlet O2 scavengers, 2,5-dimethylfuran and 1,3-diphenylisobenzofuran, were ineffective inhibitors and β-carotene only slightly effective when tested in the light system. The evidence suggests that in these two systems chlorophyll was destroyed by free radicals, probably superoxide radical, which was produced during the aerobic oxidation of bisulfite. PMID:16660075

  14. Modeling oxygenation of an ocean-atmosphere system during the Late Ordovician-Devonian

    NASA Astrophysics Data System (ADS)

    Ozaki, K.

    2013-12-01

    Throughout the Earth's history, the redox state of surface environments, biogeochemical cycles, and biological innovation/extinction have been intimately related. Therefore, understanding the long-term (over millions of years) evolution of the redox state of an ocean-atmosphere system and its controlling factors is one of the fundamental topics of Earth Sciences. In particular, Early Paleozoic is marked by the prominent biological evolution/diversification events (Cambrian explosion and Great Ordovician Biodiversification Event), implying the causal linkage between ocean oxygenation and biological innovation. On the other hand, multiple lines of evidence (such as black shale deposition, low C/S ratio of buried sediments, low molybdenum isotopic value, and iron speciation data) suggest that ocean interior had been kept in low oxygen condition until the Devonian. Dahl et al. (2010) PNAS found an increase in molybdenum isotopic value from ~1.4‰ to ~2.0‰ between ~440 Ma and ~390 Ma, implying the oceanic redox transition to a well-oxygenated condition. It was proposed that this ocean oxygenation event correlates with the diversification of vascular land plants; an enhanced burial of terrigenous organic matter increases the oxygen supply rate to an ocean-atmosphere system. Although this hypothesis for a causal linkage between the diversification of land plants and oxidation event of an ocean-atmosphere system is intriguing, it remains unclear whether the radiation of land plant is necessary to cause such redox transition. Because oxygen is most likely regulated by a combination of several feedbacks in the Earth system, it is essential to evaluate the impact of plant diversification on the oxygenation state of an ocean-atmosphere system by use of a numerical model in which C-N-P-O-S coupled biogeochemical cycles between ocean-atmosphere-sediment systems are take into account. In this study, the paleoredox history of an ocean-atmosphere system during the Paleozoic is

  15. Influence of apnoeic oxygenation in respiratory and circulatory system under general anaesthesia.

    PubMed

    Kolettas, Alexander; Grosomanidis, Vasilis; Kolettas, Vasilis; Zarogoulidis, Paul; Tsakiridis, Kosmas; Katsikogiannis, Nikolaos; Tsiouda, Theodora; Kiougioumtzi, Ioanna; Machairiotis, Nikolaos; Drylis, Georgios; Kesisis, Georgios; Beleveslis, Thomas; Zarogoulidis, Konstantinos

    2014-03-01

    Apnoeic oxygenation is an alternative technique of oxygenation which is recommended in the consecutive oxygen administration with varying flows (2-10 lt/min) through a catheter which is positioned over the keel of the trachea. Apnoeic oxygenation maintains for a significant period of time the oxygenation of blood in breathless conditions. This technique was first applied in 1947 by Draper, Whitehead, and Spencer and it was studied sporadically by other inventors too. However, the international literature shows few studies that have examined closely apnoeic oxygenation and its effects on Hemodynamic image and the respiratory system of the human body. Recently they have begun to arise some studies which deal with the application of this technique in several conditions such as difficult tracheal intubation, ventilation of guinea pigs in campaign conditions where the oxygen supply is limited and calculable, the application of this technique in combination with the use of extracorporeal removal of carbon dioxide (CO2). All the above indicate, the clinical use of this technique.

  16. Influence of apnoeic oxygenation in respiratory and circulatory system under general anaesthesia

    PubMed Central

    Kolettas, Alexander; Grosomanidis, Vasilis; Kolettas, Vasilis; Tsakiridis, Kosmas; Katsikogiannis, Nikolaos; Tsiouda, Theodora; Kiougioumtzi, Ioanna; Machairiotis, Nikolaos; Drylis, Georgios; Kesisis, Georgios; Beleveslis, Thomas; Zarogoulidis, Konstantinos

    2014-01-01

    Apnoeic oxygenation is an alternative technique of oxygenation which is recommended in the consecutive oxygen administration with varying flows (2-10 lt/min) through a catheter which is positioned over the keel of the trachea. Apnoeic oxygenation maintains for a significant period of time the oxygenation of blood in breathless conditions. This technique was first applied in 1947 by Draper, Whitehead, and Spencer and it was studied sporadically by other inventors too. However, the international literature shows few studies that have examined closely apnoeic oxygenation and its effects on Hemodynamic image and the respiratory system of the human body. Recently they have begun to arise some studies which deal with the application of this technique in several conditions such as difficult tracheal intubation, ventilation of guinea pigs in campaign conditions where the oxygen supply is limited and calculable, the application of this technique in combination with the use of extracorporeal removal of carbon dioxide (CO2). All the above indicate, the clinical use of this technique. PMID:24672687

  17. Oxygen Consumption of Tilapia and Preliminary Mass Flows through a Prototype Closed Aquaculture System

    NASA Technical Reports Server (NTRS)

    Muller, Matthew S.; Bauer, Clarence F.

    1994-01-01

    Performance of NASA's prototype CELSS Breadboard Project Closed Aquaculture System was evaluated by estimating gas exchange quantification and preliminary carbon and nitrogen balances. The total system oxygen consumption rate was 535 mg/hr kg/fish (cv = 30%) when stocked with Tilapia aurea populations (fresh weights of 97 +/- 19 to 147 +/- 36 g/fish for various trials). Oxygen consumption by T. aurea (260 mg/hr kg/fish) contributed to approximately one-half of total system demand. Continuous carbon dioxide quantification methods were analyzed using the,relation of carbon dioxide to oxygen consumption. Overall food conversion rates averaged 18.2 +/- 3.2%. Major pathways for nitrogen and carbon in the system were described with preliminary mass closure of 60-80% and 60% for nitrogen and carbon.

  18. Earth System Oxygenation: Toward an Integrated Theory of Earth Evolution

    NASA Astrophysics Data System (ADS)

    Anbar, A. D.

    2015-12-01

    The cause of the progressive oxygenation of Earth's biosphere remains poorly understood. The problem is bounded by the interplay of three irreversible, secular changes: the escape of H to space, which makes the planet more oxidized; the evolution of photoautotrophy - which converts solar energy into redox disequilbrium - and related metabolisms; and the cooling of the planet, which affects the exchange of material between Earth's reduced interior and relatively oxidized surface through a variety of processes. The first of these changes is quantitatively considered elsewhere, and is connected to the other two because H escape depends on atmospheric H2 and CH4 contents. The second of these changes is an area of vigorous research, particularly over the past decade. Important work included efforts to constrain the timing of key evolutionary events using organic geochemical and genomic records, and to understand the timing and tempo of environmental oxidation, particularly preceding the "Great Oxidation Event" (GOE) at ~2.4 Ga. As the community sorts through various debates, evidence is accumulating that the pre-GOE period was a dynamic era of transient "whiffs" of oxidation, most likely due to small amounts of biogenic O2 that appeared as early as ~3.0 Ga. The implication is that O2 sinks generally overwhelmed substantial O2 sources through the first half of Earth history, and that a decrease in sink strength and/or increase in source strength could have resulted in increasing instability of trace pO2 in the runup to the GOE. The most likely sinks are coupled to reductants in Earth's interior, which leads us to the third major change—secular cooling of the planet. It is almost certain that this cooling led to changes in mantle dynamics, rates of plate motion, and melting behaviors, which in turn affected volcanism, crust composition, hydrothermal and metamorphic alteration, ocean nutrient budgets, and recycling at subduction zones. These factors have all been

  19. Fluorinated methacrylamide chitosan hydrogel systems as adaptable oxygen carriers for wound healing.

    PubMed

    Wijekoon, Asanka; Fountas-Davis, Natalie; Leipzig, Nic D

    2013-03-01

    In this study a series of novel, biocompatible hydrogels able to repeatedly takeup and deliver oxygen at beneficial levels have been developed by conjugating various perfluorocarbon (PFC) chains to methacrylamide chitosan via Schiff base nucleophilic substitution, followed by photopolymerization to form hydrogels. The synthesized fluorinated methacrylamide chitosan (MACF) hydrogels were confirmed by high resolution (19)F NMR. Synthesized MACF hydrogels were tested for their ability to takeup and then release oxygen for future use in dermal wound healing. Depending on the PFC substitution type maximum O(2) uptake was observed within 2-6h, followed by complete release to the surrounding environment (5% CO(2)) within 12-120h at oxygen partial pressures of 1-25mm Hg h(-1), providing outstanding system tuning for wound healing and regenerative medicine. MACFs with the most fluorines per substitution showed the greatest uptake and release of oxygen. Interestingly, adding PFC chains with a fluorinated aromatic group considerably enhanced oxygen uptake and extended release compared with a linear PFC chain with the same number of fluorine molecules. MACF hydrogels proved to be readily reloaded with oxygen once release was complete, and regeneration could be performed as long as the hydrogel was intact. Fibroblasts were cultured on MACFs and assays confirmed that materials containing more fluorines per substitution supported the most cells with the greatest metabolic activity. This result was true, even without oxygenation, suggesting PFC-facilitated oxygen diffusion from the culture medium. Finally, MACF gradient hydrogels were created, demonstrating that these materials can control oxygen levels on a spatial scale of millimeters and greatly enhance cellular proliferative and metabolic responses.

  20. Potential and timescales for oxygen depletion in coastal upwelling systems: A box-model analysis

    NASA Astrophysics Data System (ADS)

    Harrison, C. S.; Hales, B.; Siedlecki, S.; Samelson, R. M.

    2016-05-01

    A simple box model is used to examine oxygen depletion in an idealized ocean-margin upwelling system. Near-bottom oxygen depletion is controlled by a competition between flushing with oxygenated offshore source waters and respiration of particulate organic matter produced near the surface and retained near the bottom. Upwelling-supplied nutrients are consumed in the surface box, and some surface particles sink to the bottom where they respire, consuming oxygen. Steady states characterize the potential for hypoxic near-bottom oxygen depletion; this potential is greatest for faster sinking rates, and largely independent of production timescales except in that faster production allows faster sinking. Timescales for oxygen depletion depend on upwelling and productivity differently, however, as oxygen depletion can only be reached in meaningfully short times when productivity is rapid. Hypoxia thus requires fast production, to capture upwelled nutrients, and fast sinking, to deliver the respiration potential to model bottom waters. Combining timescales allows generalizations about tendencies toward hypoxia. If timescales of sinking are comparable to or smaller than the sum of those for respiration and flushing, the steady state will generally be hypoxic, and results indicate optimal timescales and conditions exist to generate hypoxia. For example, the timescale for approach to hypoxia lengthens with stronger upwelling, since surface particle and nutrient are shunted off-shelf, in turn reducing subsurface respiration and oxygen depletion. This suggests that if upwelling winds intensify with climate change the increased forcing could offer mitigation of coastal hypoxia, even as the oxygen levels in upwelled source waters decline.

  1. Development of a digital adaptive control system for PO2 regulation in a membrane oxygenator.

    PubMed

    Allen, J; Fisher, A C; Gaylor, J D; Razieh, A R

    1992-09-01

    Regulation of gas exchange in artificial lungs (oxygenators) during cardiopulmonary bypass is normally achieved by manual control of the gas composition and flow in response to intermittent sampling of the arterial partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2). Manual control often results in abnormal blood gases which have been implicated in patient morbidity as well as influencing perfusion safety. Fine control of PaO2 and PaCO2 may be achieved by a combination of an in-line blood gas monitoring system and a membrane type oxygenator which is automatically regulated. The overall dynamics of the oxygenation process and control system components are complex and have nonlinear, multivariable and time-varying characteristics. Consequently, an adaptive control system approach is necessary. The implementation of a digital self-tuning control regime for PaO2 is described here. The controller is based on an explicit Linear Quadratic Gaussian (LQG) self-tuning control design which is presented using a polynomial equation approach. The controller performance was investigated in in vitro experiments. The self-tuner performed satisfactorily with various sensor/oxygenator combinations for blood flow and temperature load disturbances. In contrast, a nonadaptive (proportional-integral, PI) type of control system was found to be unsuitable.

  2. Replacement of HCFC-225 Solvent for Cleaning NASA Propulsion Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Mitchell, Mark A.; Lowrey, Nikki M.

    2015-01-01

    Since the 1990's, when the Class I Ozone Depleting Substance (ODS) chlorofluorocarbon-113 (CFC-113) was banned, NASA's rocket propulsion test facilities at Marshall Space Flight Center (MSFC) and Stennis Space Center (SSC) have relied upon hydrochlorofluorocarbon-225 (HCFC-225) to safely clean and verify the cleanliness of large scale propulsion oxygen systems. Effective January 1, 2015, the production, import, export, and new use of HCFC-225, a Class II ODS, was prohibited by the Clean Air Act. In 2012 through 2014, leveraging resources from both the NASA Rocket Propulsion Test Program and the Defense Logistics Agency - Aviation Hazardous Minimization and Green Products Branch, test labs at MSFC, SSC, and Johnson Space Center's White Sands Test Facility (WSTF) collaborated to seek out, test, and qualify a replacement for HCFC-225 that is both an effective cleaner and safe for use with oxygen systems. Candidate solvents were selected and a test plan was developed following the guidelines of ASTM G127, Standard Guide for the Selection of Cleaning Agents for Oxygen Systems. Solvents were evaluated for materials compatibility, oxygen compatibility, cleaning effectiveness, and suitability for use in cleanliness verification and field cleaning operations. Two solvents were determined to be acceptable for cleaning oxygen systems and one was chosen for implementation at NASA's rocket propulsion test facilities. The test program and results are summarized. This project also demonstrated the benefits of cross-agency collaboration in a time of limited resources.

  3. 75 FR 3141 - Airworthiness Directives; AVOX Systems and B/E Aerospace Oxygen Cylinder Assemblies, as Installed...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-20

    ... B/E Aerospace Oxygen Cylinder Assemblies, as Installed on Various Transport Airplanes AGENCY... AVOX Systems and B/E Aerospace oxygen cylinder assemblies, as installed on various transport airplanes. That AD currently requires removing certain oxygen cylinder assemblies from the airplane. This...

  4. Diurnal variation of oxygen and carbonate system parameters in Tampa Bay and Florida Bay

    USGS Publications Warehouse

    Yates, K.K.; Dufore, C.; Smiley, N.; Jackson, C.; Halley, R.B.

    2007-01-01

    Oxygen and carbonate system parameters were measured, in situ, over diurnal cycles in Tampa Bay and Florida Bay, Florida. All system parameters showed distinct diurnal trends in Tampa Bay with an average range of diurnal variation of 39.1 μmol kg− 1 for total alkalinity, 165.1 μmol kg− 1 for total CO2, 0.22 for pH, 0.093 mmol L− 1 for dissolved oxygen, and 218.1 μatm for pCO2. Average range of diurnal variation for system parameters in Tampa Bay was 73% to 93% of the seasonal range of variability for dissolved oxygen and pH. All system parameters measured in Florida Bay showed distinct variation over diurnal time-scales. However, clear diurnal trends were less evident. The average range of diurnal variability in Florida Bay was 62.8 μmol kg− 1 for total alkalinity, 130.4 μmol kg− 1 for total CO2, 0.13 for pH, 0.053 mmol L− 1 for dissolved oxygen, and 139.8 μatm for pCO2. The average range of diurnal variation was 14% to 102% of the seasonal ranges for these parameters. Diurnal variability in system parameters was most influenced by primary productivity and respiration of benthic communities in Tampa Bay, and by precipitation and dissolution of calcium carbonate in Florida Bay. Our data indicate that use of seasonal data sets without careful consideration of diurnal variability may impart significant error in calculations of annual carbon and oxygen budgets. These observations reinforce the need for higher temporal resolution measurements of oxygen and carbon system parameters in coastal ecosystems.

  5. Systems for the Storage of Molecular Oxygen - A Study.

    DTIC Science & Technology

    1980-11-25

    perfluorinated sulfonic acid groups ) which is saturated with water. Power is fed to electrodes in contact with either side of the electrolyte sheet and hydrogen is...displacement and partial pressure stripping. The most common adsorbents used are members of a group of crystalline alumi- nosilicates called zeolites...porphyrin systems some are related to biological complexes (39) or use biomolecules as lig- ands (40-43). Other studies have involved phthalocyanines

  6. Altitude Chamber Testing of the Passenger Oxygen System (POS)

    DTIC Science & Technology

    2009-08-01

    altitude chamber flight if you have a cold, sore throat , or congestion. You should inform the medical observer during the pre-flight check of any...the V-22 like cargo, has removable ballistic protection, and requires no aircraft modifications. One or two POS units can be installed in the CV-22...roll-on/roll-off” system to support passengers or paratroopers during high altitude operations and patients during medevac. POS includes a device

  7. LUMOS--A Sensitive and Reliable Optode System for Measuring Dissolved Oxygen in the Nanomolar Range.

    PubMed

    Lehner, Philipp; Larndorfer, Christoph; Garcia-Robledo, Emilio; Larsen, Morten; Borisov, Sergey M; Revsbech, Niels-Peter; Glud, Ronnie N; Canfield, Donald E; Klimant, Ingo

    2015-01-01

    Most commercially available optical oxygen sensors target the measuring range of 300 to 2 μmol L-1. However these are not suitable for investigating the nanomolar range which is relevant for many important environmental situations. We therefore developed a miniaturized phase fluorimeter based measurement system called the LUMOS (Luminescence Measuring Oxygen Sensor). It consists of a readout device and specialized "sensing chemistry" that relies on commercially available components. The sensor material is based on palladium(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorphenyl)-porphyrin embedded in a Hyflon AD 60 polymer matrix and has a KSV of 6.25 x 10-3 ppmv-1. The applicable measurement range is from 1000 nM down to a detection limit of 0.5 nM. A second sensor material based on the platinum(II) analogue of the porphyrin is spectrally compatible with the readout device and has a measurement range of 20 μM down to 10 nM. The LUMOS device is a dedicated system optimized for a high signal to noise ratio, but in principle any phase flourimeter can be adapted to act as a readout device for the highly sensitive and robust sensing chemistry. Vise versa, the LUMOS fluorimeter can be used for read out of less sensitive optical oxygen sensors based on the same or similar indicator dyes, for example for monitoring oxygen at physiological conditions. The presented sensor system exhibits lower noise, higher resolution and higher sensitivity than the electrochemical STOX sensor previously used to measure nanomolar oxygen concentrations. Oxygen contamination in common sample containers has been investigated and microbial or enzymatic oxygen consumption at nanomolar concentrations is presented.

  8. Detection of the oxygen consumption rate of migrating zebrafish by electrochemical equalization systems.

    PubMed

    Yasukawa, Tomoyuki; Koide, Masahiro; Tatarazako, Norihisa; Abe, Ryoko; Shiku, Hitoshi; Mizutani, Fumio; Matsue, Tomokazu

    2014-01-07

    A novel measurement system to determine oxygen consumption rates via respiration in migrating Zebrafish (Danio rerio) has been developed. A signal equalization system was adapted to detect oxygen in a chamber with one fish, because typical electrochemical techniques cannot measure respiration activities for migrating organisms. A closed chamber was fabricated using a pipet tip attached to a Pt electrode, and a columnar Vycor glass tip was used as the salt bridge. Pt electrode, which was attached to the chamber with one zebrafish, and Ag electrode were immersed in 10 mM potassium iodide (KI), and both the electrodes were connected externally to form a galvanic cell. Pt and Ag electrodes act as the cathode and anode to reduce oxygen and oxidize silver, respectively, allowing the deposition of insoluble silver iodide (AgI). The AgI acts as the signal source accumulated on the Ag electrode by conversion of oxygen. The amount of AgI deposited on the Ag electrode was determined by cathodic stripping voltammetry. The presence of zebrafish or its embryo led to a decrease in the stripping currents generated by a 10 min conversion of oxygen to AgI. The conversion of oxygen to AgI is disturbed by the migration of the zebrafish and allows the detection of different equalized signals corresponding to respiration activity. The oxygen consumption rates of the zebrafish and its embryo were estimated and determined to be ∼4.1 and 2.4 pmol·s(-1), respectively. The deposited AgI almost completely disappeared with a single stripping process. The signal equalization system provides a method to determine the respiration activities for migrating zebrafish and could be used to estimate environmental risk and for effective drug screening.

  9. Multimodal optical imaging system for in vivo investigation of cerebral oxygen delivery and energy metabolism

    PubMed Central

    Yaseen, Mohammad A.; Srinivasan, Vivek J.; Gorczynska, Iwona; Fujimoto, James G.; Boas, David A.; Sakadžić, Sava

    2015-01-01

    Improving our understanding of brain function requires novel tools to observe multiple physiological parameters with high resolution in vivo. We have developed a multimodal imaging system for investigating multiple facets of cerebral blood flow and metabolism in small animals. The system was custom designed and features multiple optical imaging capabilities, including 2-photon and confocal lifetime microscopy, optical coherence tomography, laser speckle imaging, and optical intrinsic signal imaging. Here, we provide details of the system’s design and present in vivo observations of multiple metrics of cerebral oxygen delivery and energy metabolism, including oxygen partial pressure, microvascular blood flow, and NADH autofluorescence. PMID:26713212

  10. Novel optoacoustic system for noninvasive continuous monitoring of cerebral venous blood oxygenation

    NASA Astrophysics Data System (ADS)

    Petrov, Yuriy; Petrov, Irene Y.; Prough, Donald S.; Esenaliev, Rinat O.

    2012-02-01

    Traumatic brain injury (TBI) and spinal cord injury are a major cause of death for individuals under 50 years of age. In the USA alone, 150,000 patients per year suffer moderate or severe TBI. Moreover, TBI is a major cause of combatrelated death. Monitoring of cerebral venous blood oxygenation is critically important for management of TBI patients because cerebral venous blood oxygenation below 50% results in death or severe neurologic complications. At present, there is no technique for noninvasive, accurate monitoring of this clinically important variable. We proposed to use optoacoustic technique for noninvasive monitoring of cerebral venous blood oxygenation by probing cerebral veins such as the superior sagittal sinus (SSS) and validated it in animal studies. In this work, we developed a novel, medical grade optoacoustic system for continuous, real-time cerebral venous blood oxygenation monitoring and tested it in human subjects at normal conditions and during hyperventilation to simulate changes that may occur in patients with TBI. We designed and built a highly-sensitive optoacoustic probe for SSS signal detection. Continuous measurements were performed in the near infrared spectral range and the SSS oxygenation absolute values were automatically calculated in real time using a special algorithm developed by our group. Continuous measurements performed at normal conditions and during hyperventilation demonstrated that hyperventilation resulted in approximately 12% decrease of cerebral venous blood oxygenation.

  11. Metal-Oxygen-Hydrogen Solid System of Controlled Composition

    NASA Astrophysics Data System (ADS)

    Ostrovskii, Victore E.

    The process of fine-crystal CuO reduction by successive small portions of H2 was studied through isothermal calorimetric, kinetic, adsorption-desorption, and stoichiometric measurements at 293-520 K and H2 pressures up to 100 Pa under conditions when equilibrium within the solid was achieved at any instant. The CuO studied was in the form of the component of the CuO-ZnO-Al2O3 system. The stoichiometry of the copper component reduced corresponded to Cu4.OH2.

  12. Oxygen isotopes as a tracer of phosphate sources and cycling in aquatic systems (Invited)

    NASA Astrophysics Data System (ADS)

    Young, M. B.; Kendall, C.; Paytan, A.

    2013-12-01

    The oxygen isotopic composition of phosphate can provide valuable information about sources and processes affecting phosphorus as it moves through hydrologic systems. Applications of this technique in soil and water have become more common in recent years due to improvements in extraction methods and instrument capabilities, and studies in multiple aquatic environments have demonstrated that some phosphorus sources may have distinct isotopic compositions within a given system. Under normal environmental conditions, the oxygen-phosphorus bonds in dissolved inorganic phosphate (DIP) can only be broken by enzymatic activity. Biological cycling of DIP will bring the phosphate oxygen into a temperature-dependent equilibrium with the surrounding water, overprinting any existing isotopic source signals. However, studies conducted in a wide range of estuarine, freshwater, and groundwater systems have found that the phosphate oxygen is often out of biological equilibrium with the water, suggesting that it is common for at least a partial isotopic source signal to be retained in aquatic systems. Oxygen isotope analysis on various potential phosphate sources such as synthetic and organic fertilizers, animal waste, detergents, and septic/wastewater treatment plant effluents show that these sources span a wide range of isotopic compositions, and although there is considerable overlap between the source groups, sources may be isotopically distinct within a given study area. Recent soil studies have shown that isotopic analysis of phosphate oxygen is also useful for understanding microbial cycling across different phosphorus pools, and may provide insights into controls on phosphorus leaching. Combining stable isotope information from soil and water studies will greatly improve our understanding of complex phosphate cycling, and the increasing use of this isotopic technique across different environments will provide new information regarding anthropogenic phosphate inputs and

  13. Frequency of Oxygen VI in Intervening QSO Absorption Systems

    NASA Astrophysics Data System (ADS)

    Burles, Scott; Tytler, David

    1994-12-01

    We have conducted the first survey for QSO with O VI lambda lambda 1032,1038 absorption lines. We obtained medium resolution (R ~ 1300), high signal-to-noise (~ 20) spectra of 11 QSOs (0.53<= zem <=2.08) taken with the Faint Object Spectrograph from the Hubble Space Telescope Archive. The O VI doublet is found exclusively in the Lyman-alpha forest. All previous surveys of metal lines in QSO absorption systems were done redward of Lyalpha emission, avoiding blending due to Lyman-alpha forest clouds. The higher density of lines in the Lyman-alpha forest demands new stringent criteria to ensure the identification of the O VI doublet. We used simulated spectra to determine the statistical significance of lines indentified in the Lyman-alpha forest. We found 12 O VI doublets and 9 are expected to be real. Six constitute a uniform sample with both lines exceeding a rest equivalent width of W_r =0.21 Angstroms. The number of O VI doublets per unit redshift is = 1.0 +/-0.6 at a mean absorption redshift of zave = 0.9. For comparable W_r the density of O VI absorbers is similar to Mg II (Tytler et al 1986; Steidel & Sargent 1992) and C IV absorbers (Sargent et al 1988; Bahcall et al 1993). We searched for other common ions in the O VI absorption systems. Out of 8 O VI absorption systems in which C IV is also found, C IV is stronger in all except zabs=1.0828 towards PG1206+459 which we believe is collisionally ionized. A rough estimate of the cosmological mass density of O VI is carried out. If we assume that O VI lines are linear, we get a lower limit of Omega (OVI) >= 3 times 10(-9) h(-1}_{100) . Since O > O VI, if the mean metal abundance were below 0.002 solar, then the accompanying Hydrogen and Helium would account for all baryons in the universe. We conclude that mean abundances are above 0.002 solar, and much greater if the gas is not highly ionized (O >> O VI).

  14. Oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system.

    PubMed

    Meng, Yao; Jost, Carsten; Mumme, Jan; Wang, Kaijun; Linke, Bernd

    2016-07-01

    In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0-431mL O2/gvs were conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431mL O2/gvs increased the methane yield by 82.2%. Aeration intensities of 0-355mL O2/gvs were conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen (DO) of UASS and AF reactors kept around 1.39±0.27 and 0.99±0.38mg/L, respectively. pH was relatively stable around 7.11±0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85±7mL/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity.

  15. Oxygen enriched combustion system performance study. Phase 2: 100 percent oxygen enriched combustion in regenerative glass melters, Final report

    SciTech Connect

    Tuson, G.B.; Kobayashi, H.; Campbell, M.J.

    1994-08-01

    The field test project described in this report was conducted to evaluate the energy and environmental performance of 100% oxygen enriched combustion (100% OEC) in regenerative glass melters. Additional objectives were to determine other impacts of 100% OEC on melter operation and glass quality, and to verify on a commercial scale that an on-site Pressure Swing Adsorption oxygen plant can reliably supply oxygen for glass melting with low electrical power consumption. The tests constituted Phase 2 of a cooperative project between the United States Department of Energy, and Praxair, Inc. Phase 1 of the project involved market and technical feasibility assessments of oxygen enriched combustion for a range of high temperature industrial heating applications. An assessment of oxygen supply options for these applications was also performed during Phase 1, which included performance evaluation of a pilot scale 1 ton per day PSA oxygen plant. Two regenerative container glass melters were converted to 100% OEC operation and served as host sites for Phase 2. A 75 ton per day end-fired melter at Carr-Lowrey Glass Company in Baltimore, Maryland, was temporarily converted to 100% OEC in mid- 1990. A 350 tpd cross-fired melter at Gallo Glass Company in Modesto, California was rebuilt for permanent commercial operation with 100% OEC in mid-1991. Initially, both of these melters were supplied with oxygen from liquid storage. Subsequently, in late 1992, a Pressure Swing Adsorption oxygen plant was installed at Gallo to supply oxygen for 100% OEC glass melting. The particular PSA plant design used at Gallo achieves maximum efficiency by cycling the adsorbent beds between pressurized and evacuated states, and is therefore referred to as a Vacuum/Pressure Swing Adsorption (VPSA) plant.

  16. General overview of an integrated lunar oxygen production/brickmaking system

    NASA Technical Reports Server (NTRS)

    Altemir, D. A.

    1993-01-01

    On the moon, various processing systems would compete for the same resources, most notably power, raw materials, and perhaps human attention. Therefore, it may be advantageous for two or more processes to be combined such that the integrated system would require fewer resources than separate systems working independently. The synergistic marriage of two such processes--lunar oxygen production and the manufacture of bricks from sintered lunar regolith--is considered.

  17. A Physiological and Human Factors Evaluation of a Novel Personal Helicopter Oxygen Delivery System

    DTIC Science & Technology

    2007-09-01

    color vision performance using the Farnsworth- Munsell 15 Hue desaturation test at the 4 moderate altitude of 12,000’. Pulse oximetry is also a widely...below provided capability for oxygen production, charging of the portable system, as well as in-flight use by aircrew. The system was tested for its...compatibility with current Aircrew Assemblies, Night Vision Goggles, aircrew duties, and emergency egress. The system was also tested on pilot

  18. General overview of an integrated lunar oxygen production/brickmaking system

    NASA Astrophysics Data System (ADS)

    Altemir, D. A.

    1993-03-01

    On the moon, various processing systems would compete for the same resources, most notably power, raw materials, and perhaps human attention. Therefore, it may be advantageous for two or more processes to be combined such that the integrated system would require fewer resources than separate systems working independently. The synergistic marriage of two such processes--lunar oxygen production and the manufacture of bricks from sintered lunar regolith--is considered.

  19. An irradiation system for photodynamic therapy with a fiber-optic sensor for measuring tissue oxygen

    NASA Astrophysics Data System (ADS)

    Quintanar, L.; Fabila, D.; Stolik, S.; de la Rosa, J. M.

    2013-11-01

    Photodynamic Therapy is a well known treatment based on the interaction of light of specific wavelength with a photosensitizing drug. In the presence of oxygen molecules, the illumination of the photosensitizer can activate the production of reactive oxygen species, which leads to the death of target cells within the treated tissue. In order to obtain the best therapy response, the tissue oxygen concentration should be measured to adjust the therapy parameters before and during the treatment. In this work, an irradiation system for 5-Aminolevulinic Acid Photodynamic Therapy is presented. It allows the application of visible light radiation of 630 nm using as a light source a high-brightness light emitting diode with an optical-power automatic control considering a light depth-distribution model. A module to measure the tissue oxygen saturation has been implemented into the system. It is based on two light emitting diodes of 660 nm and 940 nm as light sources, a photodiode as a detector and a new handheld fiber optic reflectance pulse oximetry sensor for estimating the blood oxygen saturation within the tissue. The pulse oximetry sensor was modeled through multilayered Monte Carlo simulations to study the behavior of the sensor with changes in skin thickness and melanin content.

  20. Systemic oxygen therapy versus oral enalapril for treatment of diabetic macular ischemia: a randomized controlled trial.

    PubMed

    Sharifipour, Farideh; Razzaghi, Mohammadreza; Ramezani, Alireza; Azarmina, Mohsen; Yaseri, Mehdi; Soheilian, Roham; Soheilian, Masoud

    2016-04-01

    The purpose of this study was to evaluate the structural and functional effects of systemic oxygen therapy and enalapril in patients with diabetic macular ischemia (DMI). This randomized clinical trial consisted of 105 eyes with DMI divided into three groups. Group I received systemic oxygen by face mask at a flow rate of 10 L/min; Group II received 5 mg enalapril daily; and Group III received placebo tablets for 3 months. Best-corrected visual acuity (BCVA), central macular thickness (CMT) measured by optical coherence tomography (OCT), extent of foveal avascular zone (FAZ) on fluorescein angiograms, and electroretinograms (ERG) were obtained at baseline and after 3 and 6 months. Overall, 102 patients completed the study. Baseline characteristics were not significantly different among groups. Significant improvement in BCVA and decrease in CMT and FAZ occurred at months 3 and 6 in oxygen group compared to deterioration in enalapril and control groups (All P values <0.001). ERG parameters were significantly better in oxygen group compared to enalapril group at months 3 and 6 and better than those in control group at month 3. Normobaric oxygen therapy for 3 months in DMI decreased CMT and FAZ and improved BCVA and ERG parameters. Enalapril did not show any favorable effect.

  1. Functional imaging of muscle oxygenation using a 200-channel cw NIRS system

    NASA Astrophysics Data System (ADS)

    Yamamoto, Katsuyuki; Niwayama, Masatsugu; Kohata, Daisuke; Kudo, Nobuki; Hamaoka, Takatumi; Kime, Ryotaro; Katsumura, Toshihito

    2001-06-01

    Functional imaging of muscle oxygenation using NIRS is a promising technique for evaluation of the heterogeneity of muscle function and diagnosis of peripheral vascular disease or muscle injury. We have developed a 200-channel imaging system that can measure the changes in oxygenation and blood volume of muscles and that covers wider area than previously reported systems. Our system consisted of 40 probes, a multiplexer for switching signals to and from the probes, and a personal computer for obtaining images. In each probe, one two-wavelength LED (770 and 830 nm) and five photodiodes were mounted on a flexible substrate. In order to eliminate the influence of a subcutaneous fat layer, a correction method, which we previously developed, was also used in imaging. Thus, quantitative changes in concentrations of oxy- and deoxy-hemoglobin were obtained. Temporal resolution was 1.5 s and spatial resolution was about 20 mm, depending on probe separations. Exercise tests (isometric contraction of 50% MVC) on the thigh with and without arterial occlusion were conducted, and changes in muscle oxygenation were imaged using the developed system. Results showed that the heterogeneity of deoxygenation and reoxygenation during exercise and recovery periods, respectively, were clearly observed. These results suggest that optical imaging of dynamic change in muscle oxygenation using NIRS would be useful not only for basic physiological studies but also for clinical applications with respect to muscle functions.

  2. The diversification of Paleozoic fire systems and fluctuations in atmospheric oxygen concentration

    PubMed Central

    Scott, Andrew C.; Glasspool, Ian J.

    2006-01-01

    By comparing Silurian through end Permian [≈250 million years (Myr)] charcoal abundance with contemporaneous macroecological changes in vegetation and climate we aim to demonstrate that long-term variations in fire occurrence and fire system diversification are related to fluctuations in Late Paleozoic atmospheric oxygen concentration. Charcoal, a proxy for fire, occurs in the fossil record from the Late Silurian (≈420 Myr) to the present. Its presence at any interval in the fossil record is already taken to constrain atmospheric oxygen within the range of 13% to 35% (the “fire window”). Herein, we observe that, as predicted, atmospheric oxygen levels rise from ≈13% in the Late Devonian to ≈30% in the Late Permian so, too, fires progressively occur in an increasing diversity of ecosystems. Sequentially, data of note include: the occurrence of charcoal in the Late Silurian/Early Devonian, indicating the burning of a diminutive, dominantly rhyniophytoid vegetation; an apparent paucity of charcoal in the Middle to Late Devonian that coincides with a predicted atmospheric oxygen low; and the subsequent diversification of fire systems throughout the remainder of the Late Paleozoic. First, fires become widespread during the Early Mississippian, they then become commonplace in mire systems in the Middle Mississippian; in the Pennsylvanian they are first recorded in upland settings and finally, based on coal petrology, become extremely important in many Permian mire settings. These trends conform well to changes in atmospheric oxygen concentration, as predicted by modeling, and indicate oxygen levels are a significant control on long-term fire occurrence. PMID:16832054

  3. The development of a non-cryogenic nitrogen/oxygen supply system

    NASA Technical Reports Server (NTRS)

    Greenough, B. M.

    1972-01-01

    Development of the hydrazine/water electrolysis process in a manned spacecraft to provide metabolic oxygen and both oxygen and nitrogen for cabin leakage makeup was studied. Electrode development efforts were directed to stability, achieved with catalyst additives and improved processing techniques, and a higher hydrazine conversion efficiency, achieved by reducing catalyst loading on the cathodes. Extensive testing of the one-man breadboard N2/02 system provided complete characterization of cabin atmosphere control aspects. A detailed design of a prototype modular N2/02 unit was conducted. The contact heat exchanger which is an integral component of this design was fabricated and sucessfully design-verification tested.

  4. Power System Mass Analysis for Hydrogen Reduction Oxygen Production on the Lunar Surface

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.

    2009-01-01

    The production of oxygen from the lunar regolith requires both thermal and electrical power in roughly similar proportions. This unique power requirement is unlike most applications on the lunar surface. To efficiently meet these requirements, both solar PV array and solar concentrator systems were evaluated. The mass of various types of photovoltaic and concentrator based systems were calculated to determine the type of power system that provided the highest specific power. These were compared over a range of oxygen production rates. Also a hybrid type power system was also considered. This system utilized a photovoltaic array to produce the electrical power and a concentrator to provide the thermal power. For a single source system the three systems with the highest specific power were a flexible concentrator/Stirling engine system, a rigid concentrator/Stirling engine system and a tracking triple junction solar array system. These systems had specific power values of 43, 34, and 33 W/kg, respectively. The hybrid power system provided much higher specific power values then the single source systems. The best hybrid combinations were the triple junction solar array with the flexible concentrator and the rigid concentrator. These systems had a specific power of 81 and 68 W/kg, respectively.

  5. Primo vascular system of murine melanoma and heterogeneity of tissue oxygenation of the melanoma.

    PubMed

    Hong, Minyoung; Park, Sarah S; Do, Hyunkyung; Jhon, Gil-ja; Suh, Minah; Lee, Youngmi

    2011-09-01

    Murine melanoma requires the complex development of lymphatic, vascular, and non-vascular structures. A possible relationship between the primo vascular system (PVS) and the melanoma metastasis has been proposed. In particular, the PVS may be involved in oxygen transport. Vasculogenic-like networks, similar to the PVS, have been found within melanoma tumors, but their functional relationship with the PVS and meridian structures are unclear. Herein, we report on the use of an electrochemical O(2) sensor to study oxygenation levels of melanoma tumors in mice. We consistently found higher tissue oxygenation in specific sites of tumors (n=5). These sites were strongly associated with vascular structures or the PVS. Furthermore, the PVS on the tumor surface was associated with adipose tissue. Our findings suggest that the PVS is involved in the regulation of metastasis.

  6. 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.

  7. In vivo monitoring of blood oxygenation in large veins with a triple-wavelength optoacoustic system.

    PubMed

    Brecht, H P; Prough, D S; Petrov, Y Y; Patrikeev, I; Petrova, I Y; Deyo, D J; Cicenaite, I; Esenaliev, R O

    2007-11-26

    A noninvasive optoacoustic technique could be a clinically useful alternative to existing, invasive methods for cerebral oxygenation monitoring. Recently we proposed to use an optoacoustic technique for monitoring cerebral blood oxygenation by probing large cerebral and neck veins including the superior sagittal sinus and the internal jugular vein. In these studies we used a multi-wavelength optoacoustic system with a nanosecond optical parametric oscillator as a light source and a custom-made optoacoustic probe for the measurement of the optoacoustic signals in vivo from the area of the sheep neck overlying the external jugular vein, which is similar in diameter and depth to the human internal jugular vein. Optoacoustic signals induced in venous blood were measured with high resolution despite the presence of a thick layer of tissues (up to 10 mm) between the external jugular vein and the optoacoustic probe. Three wavelengths were chosen to provide accurate and stable measurements of blood oxygenation: signals at 700 nm and 1064 nm demonstrated high correlation with actual oxygenation measured invasively with CO-Oximeter ("gold standard"), while the signal at 800 nm (isosbestic point) was independent of blood oxygenation and was used for calibration.

  8. Noninvasive cerebral blood oxygenation monitoring: clinical test of multiwavelength optoacoustic system

    NASA Astrophysics Data System (ADS)

    Petrov, Y. Y.; Prough, D. S.; Petrova, I.; Patrikeev, I. A.; Cicenaite, I.; Esenaliev, R. O.

    2007-02-01

    Continuous monitoring of cerebral blood oxygenation is critically important for treatment of patients with life-threatening conditions like severe brain injury or during cardiac surgery. We designed and built a novel multiwavelength optoacoustic system for noninvasive, continuous, and accurate monitoring of cerebral blood oxygenation. We use an Optical Parametric Oscillator as a light source. We successfully tested the system in vitro as well as in vivo in large animals (sheep) through thick tissues overlying blood vessels which drain venous blood out of the brain (e.g., superior sagittal sinus or jugular vein). Here we present the results of clinical tests of the system for continuous noninvasive cerebral blood oxygenation monitoring in the internal jugular vein of healthy volunteers. We applied our custom-built optoacoustic probe (which incorporated a wide-band acoustic transducer and an optical fiber) to the neck area overlying the internal jugular vein. We performed measurements with volunteers at 18 wavelengths in the near-infrared spectral range. Despite a thick layer of overlying connective tissue and low energy used in the experiments, we recorded signals with high signal-to-noise ratios for all volunteers. We found that the temporal (independent of signal amplitude) parameters of recorded profiles for different levels of blood oxygenation correlated well with the spectrum of effective attenuation coefficients of blood.

  9. Oxygen stress reduces zoospore survival of Phytophthora species in a simulated aquatic system

    PubMed Central

    2014-01-01

    Background The genus Phytophthora includes a group of agriculturally important pathogens and they are commonly regarded as water molds. They produce motile zoospores that can move via water currents and on their own locomotion in aquatic environments. However, zoosporic response to dissolved oxygen, an important water quality parameter, is not known. Like other water quality parameters, dissolved oxygen concentration in irrigation reservoirs fluctuates dramatically over time. The aim of this study was to determine whether and how zoospore survival may be affected by elevated and low concentrations of dissolved oxygen in water to better understand the aquatic biology of these pathogens in irrigation reservoirs. Results Zoospores of P. megasperma, P. nicotianae, P. pini and P. tropicalis were assessed for survival in 10% Hoagland’s solution at a range of dissolved concentrations from 0.9 to 20.1 mg L-1 for up to seven exposure times from 0 to 72 h. Zoospore survival was measured by resultant colony counts per ml. Zoospores of these species survived the best in control Hoagland’s solution at dissolved oxygen concentrations of 5.3 to 5.6 mg L-1. Zoospore survival rates decreased with increasing and decreasing concentration of dissolved oxygen, depending upon Phytophthora species and exposure time. Overall, P. megasperma and P. pini are less sensitive than P. nicotianae and P. tropicalis to hyperoxia and hypoxia conditions. Conclusion Zoospores in the control solution declined over time and this natural decline process was enhanced under hyperoxia and hypoxia conditions. These findings suggest that dramatic fluctuations of dissolved oxygen in irrigation reservoirs contribute to the population decline of Phytophthora species along the water path in the same reservoirs. These findings advanced our understanding of the aquatic ecology of these pathogens in irrigation reservoirs. They also provided a basis for pathogen risk mitigation by prolonging the turnover

  10. Hydrogen Purification and Recycling for an Integrated Oxygen Recovery System Architecture

    NASA Technical Reports Server (NTRS)

    Abney, Morgan B.; Greenwood, Zachary; Wall, Terry; Miller, Lee; Wheeler, Ray

    2016-01-01

    The United States Atmosphere Revitalization life support system on the International Space Station (ISS) performs several services for the crew including oxygen generation, trace contaminant control, carbon dioxide (CO2) removal, and oxygen recovery. Oxygen recovery is performed using a Sabatier reactor developed by Hamilton Sundstrand, wherein CO2 is reduced with hydrogen in a catalytic reactor to produce methane and water. The water product is purified in the Water Purification Assembly and recycled to the Oxygen Generation Assembly (OGA) to provide O2 to the crew. This architecture results in a theoretical maximum oxygen recovery from CO2 of approximately 54% due to the loss of reactant hydrogen in Sabatier-produced methane that is currently vented outside of ISS. Plasma Methane Pyrolysis technology (PPA), developed by Umpqua Research Company, provides the capability to further close the Atmosphere Revitalization oxygen loop by recovering hydrogen from Sabatier-produced methane. A key aspect of this technology approach is to purify the hydrogen from the PPA product stream which includes acetylene, unreacted methane and byproduct water and carbon monoxide. In 2015, four sub-scale hydrogen separation systems were delivered to NASA for evaluation. These included two electrolysis single-cell hydrogen purification cell stacks developed by Sustainable Innovations, LLC, a sorbent-based hydrogen purification unit using microwave power for sorbent regeneration developed by Umpqua Research Company, and a LaNi4.6Sn0.4 metal hydride produced by Hydrogen Consultants, Inc. Here we report the results of these evaluations, discuss potential architecture options, and propose future work.

  11. Hydrogen Purification and Recycling for an Integrated Oxygen Recovery System Architecture

    NASA Technical Reports Server (NTRS)

    Abney, Morgan B.; Greenwood, Zachary; Wall, Terry; Nur, Mononita; Wheeler, Richard R., Jr.; Preston, Joshua; Molter, Trent

    2016-01-01

    The United States Atmosphere Revitalization life support system on the International Space Station (ISS) performs several services for the crew including oxygen generation, trace contaminant control, carbon dioxide (CO2) removal, and oxygen recovery. Oxygen recovery is performed using a Sabatier reactor developed by Hamilton Sundstrand, wherein CO2 is reduced with hydrogen in a catalytic reactor to produce methane and water. The water product is purified in the Water Purification Assembly and recycled to the Oxygen Generation Assembly (OGA) to provide O2 to the crew. This architecture results in a theoretical maximum oxygen recovery from CO2 of approx.54% due to the loss of reactant hydrogen in Sabatier-produced methane that is currently vented outside of ISS. Plasma Pyrolysis Assembly (PPA) technology, developed by Umpqua Research Company, provides the capability to further close the Atmosphere Revitalization oxygen loop by recovering hydrogen from Sabatier-produced methane. A key aspect of this technology approach is the need to purify the hydrogen from the PPA product stream which includes acetylene, unreacted methane and byproduct water and carbon monoxide. In 2015, four sub-scale hydrogen separation systems were delivered to NASA for evaluation. These included two electrolysis single-cell hydrogen purification cell stacks developed by Sustainable Innovations, LLC, a sorbent-based hydrogen purification unit using microwave power for sorbent regeneration developed by Umpqua Research Company, and a LaNi4.6Sn0.4 metal hydride produced by Hydrogen Consultants, Inc. Here we report the results of these evaluations to-date, discuss potential architecture options, and propose future work.

  12. Theoretical and Experimental Approaches to Understanding the Anomalous Distribution of Oxygen Isotopes in the Solar System

    NASA Astrophysics Data System (ADS)

    Dominguez, Gerardo; Christensen, Elizabeth; Boyer, Charisa; Park, Manesseh; Benitez, Ezra; Nunn, Morgan; Thiemens, Mark H.; Jackson, Terri

    2016-06-01

    Decades of careful laboratory analysis of primitive meteorites have revealed an intriguing and unexplained pattern in the distribution of oxygen isotopes in the solar system. With the recent analysis of solar wind oxygen by NASA’s Genesis mission, it appears that the Sun has a distinct oxygen isotopic composition from the terrestrial planets, asteroids, and comets. These differences cannot be explained by mass-dependent diffusion and require a physical-chemical mechanism or mechanisms that separate oxygen isotopes in a non-mass dependent manner.Several hypothesis have been proposed to explain the anomalous distribution. Photochemical self-shielding of CO may explain the anomalous distribution, however, this mechanism has key weaknesses including the requirement of a very fine tuned timescale to explain the isotopic differences between the Sun and bulk of the terrestrial planets. Recently, attention has been directed at understanding specific chemical reactions that occur on interstellar dust grains due to their similarities with non-equilibrium photochemical reactions believed to be responsible for the mass-independent isotopic fractionation patterns observed in Earth’s atmosphere. A specific focus has been directed towards understanding the formation of H2O because some of its precursor (HO2, and O3) are well-known to acquire mass-independent isotopic signatures when formed in the gas-phase.In this presentation, I describe a series of laboratory astrophysical experiments whose goal is to understand the distribution of oxygen isotopes in the solar system and perhaps, by extension, the distribution in other planetary systems. Preliminary results for the isotopic composition of O3 formed at 5K will be presented as well as the first, to our knowledge, measurements of the isotopic composition of H2O (18O/16O, 17O/16O, D/H) formed at 32K. We find that H2O formed in the astrophysical conditions we simulated acquired an anomalous isotopic composition with a triple-oxygen

  13. Purge Procedures and Leak Testing for the Morgan Breathing System (MBS) 2000 Closed-Circuit Oxygen Rebreather

    DTIC Science & Technology

    2005-11-30

    AND LEAK TESTING FOR THE MORGAN BREATHING SYSTEM (MBS) 2000 CLOSED - CIRCUIT OXYGEN REBREATHER : by Dr. David Fothergill Released...TITLE AND SUBTITLE Purge Procedures and Leak Testing for the Morgan Breathing System (MBS) 2000 Closed - Circuit Oxygen Rebreather 5a. CONTRACT NUMBER...38 III. REDUCED PURGE VOLUME PROCEDURES USING A MODIFIED MBS 2000 CLOSED - CIRCUIT O2 REBREATHER

  14. Status of the Node 3 Regenerative ECLSS Water Recovery and Oxygen Generation Systems

    NASA Technical Reports Server (NTRS)

    Carrasquillo, Robyn L.; Cloud, Dale; Bedard, Jake

    2004-01-01

    NASA's Marshall Space Flight Center is providing three racks containing regenerative water recovery and oxygen generation systems (WRS and OGS) for flight on the International Space Station's (ISS) Node 3 element. The major assemblies included in these racks are the Water Processor Assembly (WPA), Urine Processor Assembly (UPA), Oxygen Generation Assembly (OGA), and the Power Supply Module (PSM) supporting the OGA. The WPA and OGA are provided by Hamilton Sundstrand Space Systems International (HSSSI), while the UPA and PSM are being designed and manufactured in-house by MSFC. The assemblies are completing the manufacturing phase and are in various stages of ORU and system level testing, to be followed by integration into the flight racks. This paper gives a current status, along with technical challenges encountered and lessons learned.

  15. Multiple electron transfer systems in oxygen reducing biocathodes revealed by different conditions of aeration/agitation.

    PubMed

    Rimboud, Mickaël; Bergel, Alain; Erable, Benjamin

    2016-08-01

    Oxygen reducing biocathodes were formed at -0.2V/SCE (+0.04V/SHE) from compost leachate. Depending on whether aeration was implemented or not, two different redox systems responsible for the electrocatalysis of oxygen reduction were evidenced. System I was observed at low potential (-0.03V/SHE) on cyclic voltammetries (CVs). It appeared during the early formation of the biocathode (few hours) and resisted the hydrodynamic conditions induced by the aeration. System II was observed at higher potential on CV (+0.46V/SHE); it required a longer lag time (up to 10days) and quiescent conditions to produce an electrochemical signal. The hydrodynamic effects produced by the forced aeration led to its extinction. From their different behaviors and examples in the literature, system I was identified as being a membrane-bound cytochrome-related molecule, while system II was identified as a soluble redox mediator excreted by the biofilm. This study highlighted the importance of controlling the local hydrodynamics to design efficient oxygen reducing biocathodes able to operate at high potential.

  16. Study of the primo-vascular system and location-dependent oxygen levels for a mouse embryo.

    PubMed

    Hong, Minyoung; Park, Sarah S; Do, Hyunkyung; Jhon, Gil-Ja; Suh, Minah; Lee, Youngmi

    2012-07-01

    The two major circulatory systems, the lymph system and the blood vessel system, play significant roles in controlling embryonic development. The primo-vascular system (PVS) was recently reported as an additional circulatory system in various animals. In this paper, the PVS in a mouse embryo was investigated. The structural characterization of the PVS in the mouse placenta and umbilical cord, which was visualized with the trypan blue staining technique, was focused on. The PVS was well_developed in the mouse placenta area. Using a nanopore-based amperometric oxygen sensor, the oxygen levels at four different areas of the embryonic brain, placenta, blood vessel, and primo-vessel of the PVS were measured. The relatively higher oxygen levels that were measured at the primo-vessels than at the brain and the placenta, while still lower than the oxygen level that was measured at the blood vessels, may suggest a role of PVS in oxygen transport.

  17. Molecular evolution of the metazoan PHD-HIF oxygen-sensing system.

    PubMed

    Rytkönen, Kalle T; Williams, Tom A; Renshaw, Gillian M; Primmer, Craig R; Nikinmaa, Mikko

    2011-06-01

    Metazoans rely on aerobic energy production, which requires an adequate oxygen supply. During reduced oxygen supply (hypoxia), the most profound changes in gene expression are mediated by transcription factors known as hypoxia-inducible factors (HIFs). HIF alpha proteins are commonly posttranslationally regulated by prolyl-4-hydroxylase (PHD) enzymes, which are direct "sensors" of cellular oxygen levels. We examined the molecular evolution of the metazoan PHD-HIF oxygen-sensing system by constructing complete phylogenies for PHD and HIF alpha genes and used computational tools to characterize the molecular changes underlying the functional divergence of PHD and HIF alpha duplicates. The presence of PHDs in metazoan genomes predates the emergence of HIF alphas. Our analysis revealed an unexpected diversity of PHD genes and HIF alpha sequence characteristics in invertebrates, suggesting that the simple oxygen-sensing systems of Caenorhabditis and Drosophila may not be typical of other invertebrate bilaterians. We studied the early vertebrate evolution of the system by sequencing these genes in early-diverging cartilaginous fishes, elasmobranchs. Cartilaginous fishes appear to have three paralogs of both PHD and HIF alpha. The novel sequences were used as outgroups for a detailed molecular analysis of PHD and HIF alpha duplicates in a major air-breathing vertebrate lineage, the mammals, and a major water-breathing vertebrate lineage, the teleosts. In PHDs, functionally divergent amino acid sites were detected near the HIF alpha-binding channel and beta2beta3 loop that defines its substrate specificity. In HIF alphas, more functional divergence was found in teleosts than in mammals, especially in the HIF-1 alpha PAS domain and HIF-2 alpha oxygen-dependent degradation (ODD) domains, which interact with PHDs. Overall, in the vertebrates, elevated substitution rates in the HIF-2 alpha N-terminal ODD domain, together with a functional divergence associated with the known

  18. The isotopic homogeneity in the early solar system: Revisiting the CAI oxygen isotopic anomaly

    NASA Astrophysics Data System (ADS)

    Ozima, M.; Yamada, A.

    2009-12-01

    Since the first discovery of the mass-independently fractionated oxygen isotopes in anhydrous, high temperature Ca-Al rich inclusion minerals in carbonaceous meteorites (CAIs) by Clayton et al. (1), their common occurrence in primitive meteorites has generally been regarded to reflect some fundamental process prevalent in the early solar nebula. The CAI oxygen isotopic composition is uniquely characterized by (i) large mass independent isotopic fractionation and (ii) their isotopic data in an oxygen three isotope plot (δ17O - δ18O (δ17O ≡ {(17O/16O)/(17O/16O)SMOW - 1} × 1000) yield nearly a straight line with a slope 1.0. In establishing these characteristics, ion microprobe analyses has played a central role, especially an isotopic mapping technique (isotopography) was crucial (e.g., 2). The extraordinary oxygen isotopic ratio in CAIs is widely attributed to the self-shielding absorption of UV radiation in CO, one of the dominant chemical compounds in the early solar nebula (3). However, the self-shielding scenario necessarily leads to the unusual prediction that a mean solar oxygen isotopic composition differs from most of planetary bodies including Earth, Moon, and Mars. If the self-shielding process were indeed responsible to the CAI oxygen isotopic anomaly, this would require a fundamental revision of the current theory of the origin of the solar system, which generally assumes the initial total vaporization of nebula material to give rise to isotopic homogenization. The GENESIS mission launched in 2001(4), which collected oxygen in the solar wind was hoped to resolve the isotopic composition of the Sun. However, because of difficulties in correcting for instrumental and more importantly for intrinsic isotopic fractionation between the SW and the Sun, a final answer is yet to be seen (5). Here, we show on the basis of the oxygen isotopic fractionation systematics that the self shielding hypothesis cannot explain the key characteristics of the CAI oxygen

  19. A foundational methodology for determining system static complexity using notional lunar oxygen production processes

    NASA Astrophysics Data System (ADS)

    Long, Nicholas James

    This thesis serves to develop a preliminary foundational methodology for evaluating the static complexity of future lunar oxygen production systems when extensive information is not yet available about the various systems under consideration. Evaluating static complexity, as part of a overall system complexity analysis, is an important consideration in ultimately selecting a process to be used in a lunar base. When system complexity is higher, there is generally an overall increase in risk which could impact the safety of astronauts and the economic performance of the mission. To evaluate static complexity in lunar oxygen production, static complexity is simplified and defined into its essential components. First, three essential dimensions of static complexity are investigated, including interconnective complexity, strength of connections, and complexity in variety. Then a set of methods is developed upon which to separately evaluate each dimension. Q-connectivity analysis is proposed as a means to evaluate interconnective complexity and strength of connections. The law of requisite variety originating from cybernetic theory is suggested to interpret complexity in variety. Secondly, a means to aggregate the results of each analysis is proposed to create holistic measurement for static complexity using the Single Multi-Attribute Ranking Technique (SMART). Each method of static complexity analysis and the aggregation technique is demonstrated using notional data for four lunar oxygen production processes.

  20. Enhancement of oxygen transfer efficiency in diffused aeration systems using liquid-film-forming apparatus.

    PubMed

    Zhu, H; Imai, T; Tani, K; Ukita, M; Sekine, M; Higuchi, T; Zhang, Z J

    2007-05-01

    Surface transfer and bubble transfer both contribute significantly to oxygen transfer in a diffused aeration system. In the present study, liquid-film-forming apparatus is successfully developed on a laboratory scale to improve considerably the surface transfer via the unique liquid film transfer technique. The experimental results show that the volumetric mass transfer coefficient for liquid-film-forming apparatus alone is found to be as much as 5.3 times higher than that for water surface and that the total volumetric mass transfer coefficient for liquid film aeration system increases by 37 % in comparison with conventional aeration system. Additionally, by tuning finely the structural parameters of the liquid-film-forming apparatus, it can also lead to high dissolved oxygen water with the dissolved oxygen percent saturation greater than 90 %. More importantly, this result is accomplished by simply offering a single-pass aeration at the depth as shallow as 26 cm. As a result, the objective of economical energy consumption in diffused aeration systems can be realized by lowering the aeration depth without sacrificing the aeration efficiency.

  1. Fan Performance Testing and Oxygen Compatibility Assessment Results for Future Space Suit Life Support Systems

    NASA Technical Reports Server (NTRS)

    Jennings, Mallory A.; Paul, Heather L.; Vogel, Matthew

    2008-01-01

    An advanced portable life support system (PLSS) for the space suit will require a small, robust, and energy-efficient system to transport the ventilation gas through the space suit for lunar Extravehicular Activity (EVA) operations. A trade study identified and compared ventilation transport technologies in commercial, military, and space applications to determine which technologies could be adapted for EVA use. Based on the trade study results, five commercially available, 24volt fans were selected for performance testing at various pressures and flow rates. Measured fan parameters included fan delta-pressures, input voltages, input electrical currents, and in some cases motor windings electrical voltages and currents. In addition, a follow-on trade study was performed to identify oxygen compatibility issues and assess their impact on fan design. This paper outlines the results of the fan performance characterization testing, as well as the results from the oxygen compatibility assessment.

  2. Fan Performance Testing and Oxygen Compatibility Assessment Results for Future Space Suit Life Support Systems

    NASA Technical Reports Server (NTRS)

    Paul, Heather L.; Jennings, Mallory A.; Vogel, Matthew

    2009-01-01

    An advanced portable life support system (PLSS) for the space suit will require a small, robust, and energyefficient system to transport the ventilation gas through the space suit for lunar Extravehicular Activity (EVA) operations. A trade study identified and compared ventilation transport technologies in commercial, military, and space applications to determine which technologies could be adapted for EVA use. Based on the trade study results, five commercially available, 24-volt fans were selected for performance testing at various pressures and flow rates. Measured fan parameters included fan delta-pressures, input voltages, input electrical currents, and in some cases motor windings electrical voltages and currents. In addition, a follow-on trade study was performed to identify oxygen compatibility issues and assess their impact on fan design. This paper outlines the results of the fan performance characterization testing, as well as the results from the oxygen compatibility assessment.

  3. Status of the International Space Station Regenerative ECLSS Water Recovery and Oxygen Generation Systems

    NASA Technical Reports Server (NTRS)

    Bagdigian, Robert M.; Cloud, Dale

    2005-01-01

    NASA is developing three racks containing regenerative water recovery and oxygen generation systems (WRS and OGS) for deployment on the International Space Station (ISS). The major assemblies included in these racks are the Water Processor Assembly (WPA), Urine Processor Assembly (UPA), Oxygen Generation Assembly (OGA), and the Power Supply Module (PSM) supporting the OGA. The WPA and OGA are provided by Hamilton Sundstrand Space Systems International (HSSSI), Inc., while the UPA and PSM are developed in- house by the Marshall Space Flight Center (MSFC). The assemblies have completed the manufacturing phase and are in various stages of testing and integration into the flight racks. This paper summarizes the status as of April 2005 and describes some of the technical challenges encountered and lessons learned over the past year.

  4. Advanced Spacesuit Portable Life Support System Oxygen Regulator Development and Testing

    NASA Technical Reports Server (NTRS)

    Campbell, Colin; Vogel, Matt R.; Watts, Carly

    2011-01-01

    The advanced spacesuit portable life support system (PLSS) oxygen regulators represent an evolutionary approach to regulator development. Several technology development prototypes have been produced that borrow much of the mechanical regulator design from the well proven Shuttle/ISS Extravehicular Mobility Unit (EMU) Secondary Oxygen Regulator, but incorporate a motor-settable pressure set-point feature that facilitates significantly greater operational flexibility. For example, this technology would enable EVA to begin at a higher suit pressure, which would reduce pre-breathe time, and then slowly step down to a lower pressure to increase suit mobility for the duration of the EVA. Comprehensive testing of the prototypes was performed on the component level as well as part of the PLSS 1.0 system level testing. Results from these tests characterize individual prototype performance and demonstrate successful operation during multiple nominal and contingency EVA modes

  5. Predicting oxygen transfer of fine bubble diffused aeration systems--model issued from dimensional analysis.

    PubMed

    Gillot, S; Capela-Marsal, S; Roustan, M; Héduit, A

    2005-04-01

    The standard oxygenation performances of fine bubble diffused aeration systems in clean water, measured in 12 cylindrical tanks (water depth from 2.4 to 6.1m), were analysed using dimensional analysis. A relationship was established to estimate the scale-up factor for oxygen transfer, the transfer number (N(T)) The transfer number, which is written as a function of the oxygen transfer coefficient (k(L)a(20)), the gas superficial velocity (U(G)), the kinematic viscosity of water (nu) and the acceleration due to gravity (g), has the same physical meaning as the specific oxygen transfer efficiency. N(T) only depends on the geometry of the tank/aeration system [the total surface of the perforated membrane (S(p)), the surface of the tank (S) or its diameter (D), the total surface of the zones covered by the diffusers ("aerated area", S(a)) and the submergence of the diffusers (h)]. This analysis allowed to better describe the mass transfer in cylindrical tanks. Within the range of the parameters considered, the oxygen transfer coefficient (k(L)a(20)) is an increasing linear function of the air flow rate. For a given air flow rate and a given tank surface area, k(L)a(20) decreases with the water depth (submergence of the diffusers). For a given water depth, k(L)a(20) increases with the number of diffusers, and, for an equal number of diffusers, with the total area of the zones covered by the diffusers. The latter result evidences the superiority of the total floor coverage over an arrangement whereby the diffusers are placed on separate grids. The specific standard oxygen transfer efficiency is independent of the air flow rate and the water depth, the drop in the k(L)a(20) being offset by the increase of the saturation concentration. For a given tank area, the impact of the total surface of the perforated membrane (S(p)) and of the aerated area (S(a)) is the same as on the oxygen transfer coefficient.

  6. Dependence of Initial Oxygen Concentration on Ozone Yield Using Inductive Energy Storage System Pulsed Power Generator

    NASA Astrophysics Data System (ADS)

    Go, Tomio; Tanaka, Yasushi; Yamazaki, Nobuyuki; Mukaigawa, Seiji; Takaki, Koichi; Fujiwara, Tamiya

    Dependence of initial oxygen concentration on ozone yield using streamer discharge reactor driven by an inductive energy storage system pulsed power generator is described in this paper. Fast recovery type diodes were employed as semiconductor opening switch to interrupt a circuit current within 100 ns. This rapid current change produced high-voltage short pulse between a secondary energy storage inductor. The repetitive high-voltage short pulse was applied to a 1 mm diameter center wire electrode placed in a cylindrical pulse corona reactor. The streamer discharge successfully occurred between the center wire electrode and an outer cylinder ground electrode of 2 cm inner diameter. The ozone was produced with the streamer discharge and increased with increasing pulse repetition rate. The ozone yield changed in proportion to initial oxygen concentration contained in the injected gas mixture at 800 ns forward pumping time of the current. However, the decrease of the ozone yield by decreasing oxygen concentration in the gas mixture at 180 ns forward pumping time of the current was lower than the decrease at 800 ns forward pumping time of the current. This dependence of the initial oxygen concentration on ozone yield at 180 ns forward pumping time is similar to that of dielectric barrier discharge reactor.

  7. Increased Oxygen Recovery from Sabatier Systems Using Plasma Pyrolysis Technology and Metal Hydride Separation

    NASA Technical Reports Server (NTRS)

    Greenwood, Zachary W.; Abney, Morgan B.; Perry, Jay L.; Miller, Lee A.; Dahl, Roger W.; Hadley, Neal M.; Wambolt, Spencer R.; Wheeler, Richard R.

    2015-01-01

    State-of-the-art life support carbon dioxide (CO2) reduction technology is based on the Sabatier reaction where less than 50% of the oxygen required for the crew is recovered from metabolic CO2. The reaction produces water as the primary product and methane as a byproduct. Oxygen recovery is constrained by the limited availability of reactant hydrogen. This is further exacerbated when Sabatier methane (CH4) is vented as a waste product resulting in a continuous loss of reactant hydrogen. Post-processing methane with the Plasma Pyrolysis Assembly (PPA) to recover hydrogen has the potential to dramatically increase oxygen recovery and thus drastically reduce the logistical challenges associated with oxygen resupply. The PPA decomposes methane into predominantly hydrogen and acetylene. Due to the highly unstable nature of acetylene, a separation system is necessary to purify hydrogen before it is recycled back to the Sabatier reactor. Testing and evaluation of a full-scale Third Generation PPA is reported and investigations into metal hydride hydrogen separation technology is discussed.

  8. The oxygen transport system of red blood cells during diabetic ketoacidosis and recovery.

    PubMed

    Ditzel, J; Standl, E

    1975-08-01

    Daily evaluations of 8 newly detected ketoacidotic diabetics showed the Bohr-effect of haemoglobin to be decreased by 50% while erythrocyte 2,3-DPG was decreased below 10 mumoles/g Hb. 2,3-DPG correlated strongly with pH during acidosis and with plasma inorganic phosphate (Pi) subsequently to the first insulin administration. Oxygen affinity of haemoglobin, measured as P50 act pH, was unchanged in ketoacidosis compared to the time, however, P50 act pH fell striking (p less than 0.001) and remained decreased up to 7 days depending upon the resynthesis of 2,3-DPG in relation to Pi. The Hill-coefeficient in reflecting the slope of the oxygen dissociation curve was diminished in ketoacidosis (p less than 0.005), and decreased further after pH-normalization (p less than 0.005). There was a close association of n with 2,3-DPG (p less than 0.001) and additionally with Pi at 2,3-DPG-levels below 10 mumoles/g Hb. Based on these findings a decreased erythrocyte oxygen release of one fifth during acidosis and more than one third after pH-correction can be hypothesised. In view of the intimate relation of Pi to the oxygen transport system it is suggesed that treatment of ketoacidosis should include Pi-sugstitution.

  9. Analysis of On-Board Oxygen and Nitrogen Generation Systems for Surface Vessels.

    DTIC Science & Technology

    1983-06-01

    22 3.2 Chemical and Physical Characteristics of Zeolite Molecular Sieves . . . . . . . . .. 25 3.3 Overview of System Components...Basic Element of a 4A Type Synthetic Zeolite . . . 27 10 a Simplified Version of Rotary Valve . ....... 35 11 a-f Comparison Among Oxygen and...carbo-gel, carbonex) . Framework silicates: Zeolites (e.g. Na-Al silicates) In both cases, pressurized air (20-100 psi depending on the appli- cation

  10. Handling and Use of Fluorine and Fluorine - Oxygen Mixtures in Rocket Systems,

    DTIC Science & Technology

    1967-01-01

    formation of chemical complexes by hydrogen fluoride or trace amounts of other system contaminants. Figures 3-5 to 3-9 generally show a film formation in...found to contain car- bon dioxide, oxygen fluoride , silicon tetrafluoride, sulfur hexafluoride , and sulfuryl fluoride . The presence of contaminants in...4 Silicon tetrafluoride -------- ɘ.05 3 Hydrogen fluoride ----------- ɘ.5 4 Sulfur hexafluoride --------- ɘ.1 4 Nitrogen trifluoride

  11. Energy transfer enhancement by oxygen perturbation of spin-forbidden electronic transitions in aromatic systems

    NASA Astrophysics Data System (ADS)

    Monguzzi, A.; Tubino, R.; Salamone, M. M.; Meinardi, F.

    2010-09-01

    Triplet-triplet energy transfer in multicomponent organic systems is usually entirely ascribed to a Dexter-type mechanism involving only short-range donor/acceptor interactions. We demonstrate that the presence of molecular oxygen introduces a perturbation to the electronic structure of one of the involved moieties which can induce a large increase in the spin-forbidden transition oscillator strength so that the otherwise negligible Förster contribution dominates the overall energy transfer rate.

  12. Investigation into the High Voltage Shutdown of the Oxygen Generator System in the International Space Station

    NASA Technical Reports Server (NTRS)

    Carpenter, Joyce E.; Gentry, Gregory J.; Diderich, Greg S.; Roy, Robert J.; Golden, John L.; VanKeuren, Steve; Steele, John W.; Rector, Tony J.; Varsik, Jerome D.; Montefusco, Daniel J.; Wilson, Mark E.; Worthy, Erica S.

    2012-01-01

    The Oxygen Generation System (OGS) Hydrogen Dome Assembly Orbital Replacement Unit (ORU) serial number 00001 suffered a cell stack high-voltage shutdown on July 5, 2010. The Hydrogen Dome Assembly ORU was removed and replaced with the on-board spare ORU serial number 00002 to maintain OGS operation. The Hydrogen Dome Assembly ORU was returned from ISS on STS-133/ULF-5 in March 2011 with test, teardown and evaluation (TT&E) and failure analysis to follow.

  13. Surface Measurements of Oxygen, Carbon Dioxide and Water Vapor Fluxes Using AN Automated Chamber System

    NASA Astrophysics Data System (ADS)

    Fentabil, M. M.; Fazackerley, S.; Nichol, C. F.

    2011-12-01

    The various soil respiration measurements that are available depend on measuring the emitted CO2 flux as organic carbon is respired aerobically. Comparative studies among the four well known methods (the open-flow infra-red gas analyzer method; the closed chamber method; the dynamic closed chamber method; and the alkali absorption method) under field conditions and laboratory experiments show differences. The discrepancies observed in these methods under field conditions could be evaluated by incorporating O2 flux measurement in addition to CO2 flux measurement. However, this is hampered by the absence of suitable equipment for measuring oxygen influx at the soil surface. A system to measure O2 fluxes at the soil surface using chamber methods has been developed. A gas handling subsystem and O2 analyser has been incorporated into an existing non-steady state automated chamber system originally designed for CO2 and H2O flux monitoring. The system consists of four 60 L soil chambers connected to temperature-controlled datalogger housing. During a measurement cycle, the chamber lid closes and the system measures changes of CO2/H2O and depletion of O2in the chamber headspace. Samples for CO2 /H2O circulate in a closed path between the chamber and an IR gas analyser. An air sample for O2 analysis is sub-sampled from this circulating air stream. Air samples for O2 are first dried using a two-stage Nafion drier. Mass flows and pressures are balanced at the pascal level prior to the gas passing into a ppm level fuel-cell oxygen analyser (Sable Systems Oxzilla). The chamber sample airstream is measured against a reference gas identically handled in a parallel air stream. A makeup gas of dry N2 is injected back to the chamber to return equimolar amounts of gas to replace the wet air removed, and hence prevent pressure fluctuation in the headspace of the chamber. The implementation of automated control of gas drying and sampling, pressure balancing, flow regulation and self

  14. Resonance tube hazards in oxygen systems. Ph.D. Thesis - Toledo Univ., 1975

    NASA Technical Reports Server (NTRS)

    Phillips, B. R.

    1982-01-01

    An experimental and analytical program was carried out to determine whether fluid dynamic oscillations could create a hazard in gaseous oxygen flow systems. The particular fluid dynamic oscillation studied was the resonance tube phenomena as it was excited in a tee-shaped configuration characteristic of configurations found in many industrial high pressure gas flow systems. The types of hazards that could be caused by the oscillations were direct heating and ignition of the piping system by the gas, the greatly augmented heating that could occur if inert contaminants were present, and the ignition of metallic contaminants. Asbestos was used as the inert contaminant; titanium, aluminum, magnesium and steel were chosen as ignitable metallic contaminants. The oscillations in the tee-shaped configuration were compared to oscillations driven by choked convergent nozzles and were found to differ markedly. Temperature generated at the end or base of the resonance tube exceeded 1089 K for both gaseous oxygen and nitrogen and reached 1645 K when asbestos was added. Aluminum in both powder and fiber form was readily ignited within the resonance tube when the supply pressures were less than 8270 kPa whereas at higher supply pressures the mixture exploded with enough violence to destory the apparatus in less than 10 sec. In addition to aluminum, magnesium, and titanium, samples of 400 series stainless steels were also ignited within the resonance tube. The ignition occurred within a few seconds after the oxygen flow began.

  15. Effects of slow deep breathing at high altitude on oxygen saturation, pulmonary and systemic hemodynamics.

    PubMed

    Bilo, Grzegorz; Revera, Miriam; Bussotti, Maurizio; Bonacina, Daniele; Styczkiewicz, Katarzyna; Caldara, Gianluca; Giglio, Alessia; Faini, Andrea; Giuliano, Andrea; Lombardi, Carolina; Kawecka-Jaszcz, Kalina; Mancia, Giuseppe; Agostoni, Piergiuseppe; Parati, Gianfranco

    2012-01-01

    Slow deep breathing improves blood oxygenation (Sp(O2)) and affects hemodynamics in hypoxic patients. We investigated the ventilatory and hemodynamic effects of slow deep breathing in normal subjects at high altitude. We collected data in healthy lowlanders staying either at 4559 m for 2-3 days (Study A; N = 39) or at 5400 m for 12-16 days (Study B; N = 28). Study variables, including Sp(O2) and systemic and pulmonary arterial pressure, were assessed before, during and after 15 minutes of breathing at 6 breaths/min. At the end of slow breathing, an increase in Sp(O2) (Study A: from 80.2±7.7% to 89.5±8.2%; Study B: from 81.0±4.2% to 88.6±4.5; both p<0.001) and significant reductions in systemic and pulmonary arterial pressure occurred. This was associated with increased tidal volume and no changes in minute ventilation or pulmonary CO diffusion. Slow deep breathing improves ventilation efficiency for oxygen as shown by blood oxygenation increase, and it reduces systemic and pulmonary blood pressure at high altitude but does not change pulmonary gas diffusion.

  16. Measurement of the oxygen partial pressure and thermodynamic modeling of the U-Nd-O system

    NASA Astrophysics Data System (ADS)

    Lee, Seung Min; Knight, Travis W.; McMurray, Jacob W.; Besmann, Theodore M.

    2016-05-01

    Fission products greatly impact the properties of fuel necessitating a thorough understanding of the thermochemical properties of oxide fuels with fission products. However, thermochemical data for the U-Nd-O system is insufficient even though neodymium is a major fission product. As neodymium will likely be present as a solute in UO2, this research focuses on the study of (U1-yNdy)O2±x. Experimental measurements and analyses of the oxygen partial pressure (pO2)-temperature-oxygen to metal ratio (O/M ratio) relationships were performed using a thermogravimetric analyzer (TGA) and an oxygen analyzer. Thermodynamic computational modeling was performed using the CALPHAD (CALculation of PHAse Diagrams) method with the FactSage software. The Gibbs energy of the (U1-yNdy)O2±x solid solution was described by the compound energy formalism (CEF), which is based on earlier thermodynamic modeling data of the binary U-O system from Guéneau et al.. The thermodynamic and phase diagram data of the U-Nd-O system produced in this work show good agreement with the experimental data.

  17. Influence factors for the oxidation of pyrite by oxygen and birnessite in aqueous systems.

    PubMed

    Qiu, Guohong; Luo, Yao; Chen, Cheng; Lv, Qiang; Tan, Wenfeng; Liu, Fan; Liu, Chengshuai

    2016-07-01

    The oxidation of exposed pyrite causes acid mine drainage, soil acidification, and the release of toxic metal ions. As the important abiotic oxidants in supergene environments, oxygen and manganese oxides participate in the oxidation of pyrite. In this work, the oxidation processes of natural pyrite by oxygen and birnessite were studied in simulated systems, and the influence of pH, Fe(II) and Cr(III) on the intermediates and redox rate was investigated. SO4(2-) and elemental S were formed as the major and minor products, respectively, during the oxidation processes. Ferric (hydr) oxides including Fe(OH)3 and goethite were formed with low degree of crystallinity. Low pH and long-term reaction facilitated the formation of goethite and ferric hydroxide, respectively. The rate of pyrite oxidation by birnessite was enhanced in the presence of air (oxygen), and Fe(II) ions played a key role in the redox process. The addition of Fe(II) ions to the reaction system significantly enhanced the oxidation rate of pyrite; however, the presence of Cr(III) ions remarkably decreased the pyrite oxidation rate in aqueous systems. The introduction of Fe(II) ions to form a Fe(III)/Fe(II) redox couple facilitated the electron transfer and accelerated the oxidation rate of pyrite. The present work suggests that isolation from air and decreasing the concentration of Fe(II) ions in aqueous solutions might be effective strategies to reduce the oxidation rate of pyrite in mining soils.

  18. Chesapeake Bay Forecast System: Oxygen Prediction for the Sustainable Ecosystem Management

    NASA Astrophysics Data System (ADS)

    Mathukumalli, B.; Long, W.; Zhang, X.; Wood, R.; Murtugudde, R. G.

    2010-12-01

    The Chesapeake Bay Forecast System (CBFS) is a flexible, end-to-end expert prediction tool for decision makers that will provide customizable, user-specified predictions and projections of the region’s climate, air and water quality, local chemistry, and ecosystems at days to decades. As a part of CBFS, the long-term water quality data were collected and assembled to develop ecological models for the sustainable management of the Chesapeake Bay. Cultural eutrophication depletes oxygen levels in this ecosystem particularly in summer which has several negative implications on the structure and function of ecosystem. In order to understand dynamics and prediction of spatially-explicit oxygen levels in the Bay, an empirical process based ecological model is developed with long-term control variables (water temperature, salinity, nitrogen and phosphorus). Statistical validation methods were employed to demonstrate usability of predictions for management purposes and the predicted oxygen levels are quite faithful to observations. The predicted oxygen values and other physical outputs from downscaling of regional weather and climate predictions, or forecasts from hydrodynamic models can be used to forecast various ecological components. Such forecasts would be useful for both recreational and commercial users of the bay (for example, bass fishing). Furthermore, this work can also be used to predict extent of hypoxia/anoxia not only from anthropogenic nutrient pollution, but also from global warming. Some hindcasts and forecasts are discussed along with the ongoing efforts at a mechanistic ecosystem model to provide prognostic oxygen predictions and projections and upper trophic modeling using an energetics approach.

  19. Implementation and 8-year follow-up of an uninterrupted oxygen supply system in a hospital in The Gambia

    PubMed Central

    Light, J. D.; Ebonyi, A. O.; N'Jai, P. C.; Ideh, R. C.; Ebruke, B. E.; Nyassi, E.; Peel, D.

    2016-01-01

    SUMMARY SETTING: A 42-bed hospital operated by the Medical Research Council (MRC) Unit in The Gambia. OBJECTIVE: To devise, test and evaluate a cost-efficient uninterrupted oxygen system in the MRC Hospital. DESIGN: Oxygen cylinders were replaced with oxygen concentrators as the primary source of oxygen. An uninterruptable power supply (UPS) ensured continuity of power. Hospital staff were trained on the use of the new system. Eight years post-installation, an analysis of concentrator maintenance needs and costs was conducted and user feedback obtained to assess the success of the system. RESULTS: The new system saved at least 51% of oxygen supply costs compared to cylinders, with savings likely to have been far greater due to cylinder leakages. Users indicated that the system is easier to use and more reliable, although technical support and staff training are still needed. CONCLUSION: Oxygen concentrators offer long-term cost savings and an improved user experience compared to cylinders; however, some technical support and maintenance are needed to upkeep the system. A UPS dedicated to oxygen concentrators is an appropriate solution for settings where power interruptions are frequent but short in duration. This approach can be a model for health systems in settings with similar infrastructure. PMID:27393551

  20. Energy-Related Small Molecule Activation Reactions: Oxygen Reduction and Hydrogen and Oxygen Evolution Reactions Catalyzed by Porphyrin- and Corrole-Based Systems.

    PubMed

    Zhang, Wei; Lai, Wenzhen; Cao, Rui

    2017-02-22

    Globally increasing energy demands and environmental concerns related to the use of fossil fuels have stimulated extensive research to identify new energy systems and economies that are sustainable, clean, low cost, and environmentally benign. Hydrogen generation from solar-driven water splitting is a promising strategy to store solar energy in chemical bonds. The subsequent combustion of hydrogen in fuel cells produces electric energy, and the only exhaust is water. These two reactions compose an ideal process to provide clean and sustainable energy. In such a process, a hydrogen evolution reaction (HER), an oxygen evolution reaction (OER) during water splitting, and an oxygen reduction reaction (ORR) as a fuel cell cathodic reaction are key steps that affect the efficiency of the overall energy conversion. Catalysts play key roles in this process by improving the kinetics of these reactions. Porphyrin-based and corrole-based systems are versatile and can efficiently catalyze the ORR, OER, and HER. Because of the significance of energy-related small molecule activation, this review covers recent progress in hydrogen evolution, oxygen evolution, and oxygen reduction reactions catalyzed by porphyrins and corroles.

  1. SYSTEM DESIGN AND ANALYSIS FOR CONCEPTUAL DESIGN OF OXYGEN-BASED PC BOILER

    SciTech Connect

    Zhen Fan; Andrew Seltzer

    2003-11-01

    The objective of the system design and analysis task of the Conceptual Design of Oxygen-Based PC Boiler study is to optimize the PC boiler plant by maximizing system efficiency. Simulations of the oxygen-fired plant with CO{sub 2} sequestration were conducted using Aspen Plus and were compared to a reference air-fired 460 Mw plant. Flue gas recycle is used in the O{sub 2}-fired PC to control the flame temperature. Parametric runs were made to determine the effect of flame temperature on system efficiency and required waterwall material and thickness. The degree of improvement on system efficiency of various modifications including hot gas recycle, purge gas recycle, flue gas feedwater recuperation, and recycle purge gas expansion were investigated. The selected O{sub 2}-fired design case has a system efficiency of 30.1% compared to the air-fired system efficiency of 36.7%. The design O{sub 2}-fired case requires T91 waterwall material and has a waterwall surface area of only 44% of the air-fired reference case. Compared to other CO{sub 2} sequestration technologies, the O{sub 2}-fired PC is substantially better than both natural gas combined cycles and post CO{sub 2} removal PCs and is slightly better than integrated gasification combined cycles.

  2. 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

  3. A hydrogel system for stimulus-responsive, oxygen-sensitive in situ gelation.

    PubMed

    Goessl, Andreas; Tirelli, Nicola; Hubbell, Jeffrey A

    2004-01-01

    A hydrogel system that is designed to gel due to oxidation by molecular oxygen is described. This is achieved by the use of a branched poly(ethylene glycol) modified with thiol end groups. A stable precursor molecule, starPEG thioacetate, was synthesized by radical addition of thioacetic acid to an intermediate starPEG allyl ether. Rapid deprotection of the thiol can be achieved using a base, e.g. sodium hydroxide, quantitatively liberating a thiol group and a non-toxic acetate ion. This step can be carried out under anaerobic conditions, yielding a solution with known thiol content that can be stored. The reaction with oxygen is accelerated by the use of a catalyst based on Fenton chemistry, which makes the material useful for biomedical applications where in situ polymerization of an injectable material is beneficial. This gelation takes place under near physiological conditions without the need for a cross-linking agent.

  4. Conditions for economic benefit by using lunar oxygen for earth-moon transportation systems

    NASA Astrophysics Data System (ADS)

    Reichert, M.; Lingner, S.; Seboldt, W.

    1992-08-01

    The paper considers the use of MOONLOX, lunar oxygen, for an earth-moon transportation system consisting of an aeroassisted orbital transfer vehicle and a lunar bus for lunar descent/ascent. Conditions for economic benefit are discussed, and the processing concept of a lunar oxygen plant based on fluorination is presented. It is contended that the necessary supply rate from earth from MOONLOX production must be smaller than a critical number for each considered MOONLOX-utilization scenario to yield a saving of mass launched into LEO (compared to a 'reference scenario' with an earth-derived propellant. The MOONLOX production costs must fall below the calculated upper limits (parametrically dependent of launch costs). It is inferred that for the MOONLOX production process by fluorination, fluorine recycling is highly desirable.

  5. Regulation of signal transduction by reactive oxygen species in the cardiovascular system

    PubMed Central

    Brown, David I.; Griendling, Kathy K.

    2015-01-01

    Oxidative stress has long been implicated in cardiovascular disease, but more recently, the role of reactive oxygen species in normal physiological signaling has been elucidated. Signaling pathways modulated by reactive oxygen species (ROS) are complex and compartmentalized, and we are only beginning to identify the molecular modifications of specific targets. Here we review the current literature regarding ROS signaling in the cardiovascular system, focusing on the role of ROS in normal physiology and how dysregulation of signaling circuits contributes to cardiovascular diseases including atherosclerosis, ischemia-reperfusion injury, cardiomyopathy and heart failure. In particular, we consider how ROS modulate signaling pathways related to phenotypic modulation, migration and adhesion, contractility, proliferation and hypertrophy, angiogenesis, endoplasmic reticulum stress, apoptosis and senescence. Understanding the specific targets of ROS may guide the development of the next generation of ROS-modifying therapies to reduce morbidity and mortality associated with oxidative stress. PMID:25634975

  6. An automated system for oxygen-18 water recovery and fluorine-18 delivery

    NASA Astrophysics Data System (ADS)

    Schueller, Michael J.; Ferrieri, Richard A.; Schlyer, David J.

    2005-12-01

    BNL has recently purchased an EBCO TR-19 cyclotron for routine isotope production. A system has been built to recover oxygen-18 enriched water from the fluorine-18 target, and then transport the F-18 a distance of 50 m to a shielded dose splitter. The remotized system provides the operator with feedback on flow rates and radiation levels during processing. Recovery of the 2.6 mL of enriched water and transport of the F-18 to the radiochemistry labs takes under 10 min, with more than 80% of the activity arriving in the chemistry lab.

  7. POGO Instabilities Suppression Evaluation. [from dynamic analysis of liquid oxygen feed system

    NASA Technical Reports Server (NTRS)

    Farrel, E. C.; Fenwick, J. R.

    1973-01-01

    A dynamic (frequency response) analysis was made of a liquid oxygen feed system consisting of a low-speed inducer, a high-speed main pump and a positive displacement pulser utilized for simulating pogo induced pressure oscillations. Based on the results of the analysis, an active control system for suppression of pulser generated pressure oscillations was designed, fabricated and tested. The test results verified that the suppressor was effective in attenuating the generated pressure oscillations over the frequency range from 10 to 30 Hz.

  8. A model for the water-oxidation and recovery systems of the oxygen-evolving complex.

    PubMed

    Yatabe, Takeshi; Kikkawa, Mitsuhiro; Matsumoto, Takahiro; Nakai, Hidetaka; Kaneko, Kenji; Ogo, Seiji

    2014-02-28

    We propose a model for the water-oxidation and recovery systems of the oxygen-evolving complex (OEC) of the photosystem II (PSII) enzyme. The whole system is constructed from two catalytic cycles, conducted as a tandem reaction: (i) a water-oxidation loop uses cerium(IV) ammonium nitrate as an oxidant to activate a dimanganese complex for water-oxidation and thereby liberate a molecule of O2 and (ii) a recovery loop begins with photoinhibition of the dimanganese complex but then uses O2 to reactivate the manganese centre. The net result is a catalytic water-oxidation catalyst that can use self-generated O2 for recovery.

  9. Development and Testing of a Methane/Oxygen Catalytic Microtube Ignition System for Rocket Propulsion

    NASA Technical Reports Server (NTRS)

    Deans, Matthew

    2012-01-01

    This study sought to develop a catalytic ignition advanced torch system with a unique catalyst microtube design that could serve as a low energy alternative or redundant system for the ignition of methane and oxygen rockets. Development and testing of iterations of hardware was carried out to create a system that could operate at altitude and produce a torch. A unique design was created that initiated ignition via the catalyst and then propagated into external staged ignition. This system was able to meet the goals of operating across a range of atmospheric and altitude conditions with power inputs on the order of 20 to 30 watts with chamber pressures and mass flow rates typical of comparable ignition systems for a 100 lbf engine.

  10. Development and Testing of a Methane/Oxygen Catalytic Microtube Ignition System for Rocket Propulsion

    NASA Technical Reports Server (NTRS)

    Deans, Matthew C.; Schneider, Steven J.

    2012-01-01

    This study sought to develop a catalytic ignition advanced torch system with a unique catalyst microtube design that could serve as a low energy alternative or redundant system for the ignition of methane and oxygen rockets. Development and testing of iterations of hardware was carried out to create a system that could operate at altitude and produce a torch. A unique design was created that initiated ignition via the catalyst and then propagated into external staged ignition. This system was able to meet the goals of operating across a range of atmospheric and altitude conditions with power inputs on the order of 20 to 30 watts with chamber pressures and mass flow rates typical of comparable ignition systems for a 100 Ibf engine.

  11. Oxygen transport membrane reactor based method and system for generating electric power

    DOEpatents

    Kelly, Sean M.; Chakravarti, Shrikar; Li, Juan

    2017-02-07

    A carbon capture enabled system and method for generating electric power and/or fuel from methane containing sources using oxygen transport membranes by first converting the methane containing feed gas into a high pressure synthesis gas. Then, in one configuration the synthesis gas is combusted in oxy-combustion mode in oxygen transport membranes based boiler reactor operating at a pressure at least twice that of ambient pressure and the heat generated heats steam in thermally coupled steam generation tubes within the boiler reactor; the steam is expanded in steam turbine to generate power; and the carbon dioxide rich effluent leaving the boiler reactor is processed to isolate carbon. In another configuration the synthesis gas is further treated in a gas conditioning system configured for carbon capture in a pre-combustion mode using water gas shift reactors and acid gas removal units to produce hydrogen or hydrogen-rich fuel gas that fuels an integrated gas turbine and steam turbine system to generate power. The disclosed method and system can also be adapted to integrate with coal gasification systems to produce power from both coal and methane containing sources with greater than 90% carbon isolation.

  12. [Oxygen-transporting function of the blood circulation system in sevoflurane anesthesia during myocardial revascularization under extracorporeal circulation].

    PubMed

    Skopets, A A; Lomivorotov, V V; Karakhalis, N B; Makarov, A A; Duman'ian, E S; Lomivorotova, L V

    2009-01-01

    The purpose of the study was to evaluate the efficiency of oxygen-transporting function of the circulatory system under sevoflurane anesthesia during myocardial revascularization operations under extracorporeal circulation. Twenty-five patients with coronary heart disease were examined. Mean blood pressure, heart rate, cardiac index, total peripheral vascular resistance index, pulmonary pressure, pulmonary wedge pressure, and central venous pressure were measured. Arterial and mixed venous blood oxygen levels, oxygen delivery and consumption index, arteriovenous oxygen difference, and glucose and lactate concentrations were calculated. The study has demonstrated that sevoflurane is an effective and safe anesthetic for myocardial revascularization operations in patients with coronary heart disease. The use of sevoflurane contributes to steady-state oxygen-transporting function of the circulatory system at all surgical stages.

  13. First report of the successful operation of a side stream supersaturation hypolimnetic oxygenation system in a eutrophic, shallow reservoir.

    PubMed

    Gerling, Alexandra B; Browne, Richard G; Gantzer, Paul A; Mobley, Mark H; Little, John C; Carey, Cayelan C

    2014-12-15

    Controlling hypolimnetic hypoxia is a key goal of water quality management. Hypoxic conditions can trigger the release of reduced metals and nutrients from lake sediments, resulting in taste and odor problems as well as nuisance algal blooms. In deep lakes and reservoirs, hypolimnetic oxygenation has emerged as a viable solution for combating hypoxia. In shallow lakes, however, it is difficult to add oxygen into the hypolimnion efficiently, and a poorly designed hypolimnetic oxygenation system could potentially result in higher turbidity, weakened thermal stratification, and warming of the sediments. As a result, little is known about the viability of hypolimnetic oxygenation in shallow bodies of water. Here, we present the results from recent successful tests of side stream supersaturation (SSS), a type of hypolimnetic oxygenation system, in a shallow reservoir and compare it to previous side stream deployments. We investigated the sensitivity of Falling Creek Reservoir, a shallow (Zmax = 9.3 m) drinking water reservoir located in Vinton, Virginia, USA, to SSS operation. We found that the SSS system increased hypolimnetic dissolved oxygen concentrations at a rate of ∼1 mg/L/week without weakening stratification or warming the sediments. Moreover, the SSS system suppressed the release of reduced iron and manganese, and likely phosphorus, from the sediments. In summary, SSS systems hold great promise for controlling hypolimnetic oxygen conditions in shallow lakes and reservoirs.

  14. Oxides of LANTHANUM(1-X) Strontium(x) COBALT(1 - Iron(y) OXYGEN(3) for Oxygen and Electrical Delivery Systems

    NASA Astrophysics Data System (ADS)

    Tai, Lone-Wen Frank

    Perovskite-type compounds in the system La_{1-x}Sr_{x}Co _{1-y}Fe_{y}O_ {3-delta have been considered as potential cathode materials for solid oxide fuel cells. The purpose of this study was to evaluate the structural, electrical, thermochemical properties of these compositions. The first and second papers of this dissertation dealt with the material synthesis, crystal structure, thermal expansion, thermogravimetry, electrical conductivity, and thermoelectricity of La_{0.8 }Sr_{0.2}Co_{1-y}Fe _{y}O_3 (y = 0-1) and La_{1-x}Sr_{x}Co _{0.2}Fe_{0.8}O_3 (x = 0-1) in air, respectively. Electrical conductivities and thermal expansion coefficients for these compositions were found to increase with Sr and Co contents. The unique temperature and composition dependence of the electrical conductivity observed in both systems were semi-empirically modeled by incorporating several mechanisms which include the hopping conduction of small polarons, a thermally activated charge disproportionation of Co^{3+ }, the ionic compensation by oxygen vacancy, and a preferential electronic compensation of acceptor by forming Fe^{4+} over Co^{4+}.. Phase stability, oxygen content, electrical conductivity, and Seebeck coefficient of La_ {1-x}Sr_{x}Co_{0.2 }Fe_{0.8}O_{3-delta } (x = 0, 0.2, 0.4) as function of temperature and oxygen activity were reported in the third paper. Both the oxygen deficiency and phase stability of compositions with y = 0.8 were found considerably high. It has been demonstrated that the degree of oxygen deficiency in these compositions significantly influences their structural and electrical properties, especially in the high temperature region.

  15. Contaminant Removal from Oxygen Production Systems for In Situ Resource Utilization

    NASA Technical Reports Server (NTRS)

    Anthony, Stephen M.; Santiago-Maldonado, Edgardo; Captain, James G.; Pawate, Ashtamurthy S.; Kenis, Paul J. A.

    2012-01-01

    The In Situ Resource Utilization (ISRU) project has been developing technologies to produce oxygen from lunar regolith to provide consumables to a lunar outpost. The processes developed reduce metal oxides in the regolith to produce water, which is then electrolyzed to produce oxygen. Hydrochloic and hydrofluoric acids are byproducts of the reduction processes, as halide minerals are also reduced at oxide reduction conditions. Because of the stringent water quality requirements for electrolysis, there is a need for a contaminant removal process. The Contaminant Removal from Oxygen Production Systems (CROPS) team has been developing a separation process to remove these contaminants in the gas and liquid phase that eliminates the need for consumables. CROPS has been using Nafion, a highly water selective polymeric proton exchange membrane, to recover pure water from the contaminated solution. Membrane thickness, product stream flow rate, and acid solution temperature and concentration were varied with the goal of maximizing water permeation and acid rejection. The results show that water permeation increases with increasing solution temperature and product stream flow rate, while acid rejection increases with decreasing solution temperature and concentration. Thinner membranes allowed for higher water flux and acid rejection than thicker ones. These results were used in the development of the hardware built for the most recent Mars ISRU demonstration project.

  16. Purification of liquid metal systems with sodium coolant from oxygen using getters

    NASA Astrophysics Data System (ADS)

    Kozlov, F. A.; Konovalov, M. A.; Sorokin, A. P.

    2016-05-01

    For increasing the safety and economic parameters of nuclear power stations (NPSs) with sodium coolant, it was decided to install all systems contacting radioactive sodium, including purification systems of circuit I, in the reactor vessel. The performance and capacity of cold traps (CTs) (conventional element of coolant purification systems) in these conditions are limited by their volume. It was proposed to use hot traps (HTs) in circuit I for coolant purification from oxygen. It was demonstrated that, at rated parameters of the installation when the temperature of the coolant streamlining the getter (gas absorber) is equal to 550°C, the hot trap can provide the required coolant purity. In shutdown modes at 250-300°C, the performance of the hot trap is reduced by four orders of magnitude. Possible HT operation regimes for shutdown modes and while reaching rated parameters were proposed and analyzed. Basic attention was paid to purification modes at power rise after commissioning and accidental contamination of the coolant when the initial oxygen concentration in it reached 25 mln-1. It was demonstrated that the efficiency of purification systems can be increased using HTs with the getter in the form of a foil or granules. The possibility of implementing the "fast purification" mode in which the coolant is purified simultaneously with passing over from the shutdown mode to the rated parameters was substantiated.

  17. Oxygen Generator System Mars In-Situ Propellant Production Precursor Flight

    NASA Technical Reports Server (NTRS)

    Sridhar, K. R.; Gottmann, M.; Baird, R. S.

    1999-01-01

    The 2001 Lander to Mars will carry the first ever In situ Resource Utilization (ISRU) payload to Mars. This payload, the Mars In-situ Propellant production Precursor (MIP), will demonstrate a variety of technologies that will be required for future ISRU Mars indigenous material processing plant designs. One of those technologies is that of extracting oxygen from the predominantly carbon dioxide atmosphere of Mars, a prerequisite for future sample return and human missions to Mars. The Oxygen Generator Subsystem (OGS) portion of the MIP will demonstrate this and is the focus of this paper. The primary objective of the OGS is to demonstrate the production of oxygen from Mars atmospheric gases. Secondary objectives are to measure the performance and reliability of oxygen generation hardware in actual mission environments over an extended time. Major constraints on the OGS design came from several sources. The Lander provides power to the system from solar power that is harnessed by photovoltaic arrays. This limited OGS to daytime only operations (six to eight hours) and a maximum power of 15W. The reliance on solar power necessitated thermal cycling of the OGS between Mars ambient and OGS operating temperatures. The Lander also limited the total mass of the MIP payload to 7.5 kg with a correspondingly small volume, and the OGS was one of six experiments in the MIP Mass and volume were to be minimized. Another constraint was cost. Mission funding, as always, was tight. Cost was to be minimized. In short the OGS design had to be low power (<15 Watts), low mass (1 kg), low volume, low cost, and be capable of cyclical operations for an extended stay on Mars. After extensive research, a zirconia based solid oxide electrolyzer design was selected.

  18. Oxygen Generator System Mars In-Situ Propellant Production Precursor Flight

    NASA Technical Reports Server (NTRS)

    Sridhar, K. R.; Gottmann, M.; Baird, R. S.

    1999-01-01

    The 2001 Lander to Mars will carry the first ever ISRU payload to Mars. This payload, the Mars In-situ Propellant production Precursor (MIP), will demonstrate a variety of technologies that will be required for future ISRU Mars indigenous material processing plant designs. One of those technologies is that of extracting oxygen from the predominantly carbon dioxide atmosphere of Mars, a prerequisite for future sample return and human missions to Mars. The Oxygen Generator Subsystem (OGS) portion of the MIP will demonstrate this and is the focus of this paper. The primary objective of the OGS is to demonstrate the production of oxygen from Mars atmospheric gases. Secondary objectives are to measure the performance and reliability of oxygen generation hardware in actual mission environments over an extended time. Major constraints on the OGS design came from several sources. The Lander provides power to the system from solar power that is harnessed by photovoltaic arrays. This limited OGS to daytime only operations (six to eight hours) and a maximum power of 15W. The reliance on solar power necessitated thermal cycling of the OGS between Mars ambient and OGS operating temperatures. The Lander also limited the total mass of the MIP payload to 7.5 kg with a correspondingly small volume, and the OGS was one of six experiments in the MIP. Mass and volume were to be minimized. Another constraint was cost. Mission funding, as always, was tight. Cost was to be minimized. In short the OGS design had to be low power (<15 Watts), low mass (1 kg), low volume, low cost, and be capable of cyclical operations for an extended stay on Mars. After extensive research, a zirconia based solid oxide electrolyzer design was selected.

  19. Female rats are more susceptible to central nervous system oxygen toxicity than male rats

    PubMed Central

    Held, Heather E.; Pilla, Raffaele; Ciarlone, Geoffrey E.; Landon, Carol S.; Dean, Jay B.

    2014-01-01

    Abstract Tonic–clonic seizures typify central nervous system oxygen toxicity (CNS‐OT) in humans and animals exposed to high levels of oxygen, as are encountered during scuba diving. We previously demonstrated that high doses of pseudoephedrine (PSE) decrease the latency to seizure (LS) for CNS‐OT in young male rats. This study investigated whether female rats respond similarly to PSE and hyperbaric oxygen (HBO). We implanted 60 virgin stock (VS) and 54 former breeder (FB) female rats with radio‐telemetry devices that measured brain electrical activity. One week later, rats were gavaged with saline or PSE in saline (40, 80, 120, 160, or 320 mg/kg) before diving to five atmospheres absolute in 100% oxygen. The time between reaching maximum pressure and exhibiting seizure was LS. Vaginal smears identified estrus cycle phase. PSE did not decrease LS for VS or FB, primarily because they exhibited low LS for all conditions tested. VS had shorter LS than males at 0, 40, and 80 mg/kg (−42, −49, and −57%, respectively). FB also had shorter LS than males at 0, 40, and 80 mg/kg (−60, −86, and −73%, respectively). FB were older than VS (286 ± 10 days vs. 128 ± 5 days) and weighed more than VS (299 ± 2.7 g vs. 272 ± 2.1 g). Males tested were younger (88 ± 2 days), heavier (340 ± 4.5 g), and gained more weight postoperatively (7.2 ± 1.6 g) than either VS (−0.4 ± 1.5 g) or FB (−1.6 ± 1.5 g); however, LS correlated poorly with age, body mass, change in body mass, and estrus cycle phase. We hypothesize that differences in sex hormones underlie females' higher susceptibility to CNS‐OT than males. PMID:24771690

  20. Study of liquid oxygen/liquid hydrogen auxiliary propulsion systems for the space tug

    NASA Technical Reports Server (NTRS)

    Nichols, J. F.

    1975-01-01

    Design concepts are considered that permit use of a liquid-liquid (as opposed to gas-gas) oxygen/hydrogen thrust chamber for attitude control and auxiliary propulsion thrusters on the space tug. The best of the auxiliary propulsion system concepts are defined and their principal characteristics, including cost as well as operational capabilities, are established. Design requirements for each of the major components of the systems, including thrusters, are developed at the conceptual level. The competitive concepts considered use both dedicated (separate tanks) and integrated (propellant from main propulsion tanks) propellant supply. The integrated concept is selected as best for the space tug after comparative evaluation against both cryogenic and storable propellant dedicated systems. A preliminary design of the selected system is established and recommendations for supporting research and technology to further the concept are presented.

  1. Development of a non-cryogenic nitrogen/oxygen supply system. [for spacecraft environments

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Modular components were refined or replaced to improve the performance of the electrolysis module in a system which generates both oxygen and hydrogen from hydrazine hydrate. Significant mechanical and electrical performance improvements were achieved in the cathode. Improvements were also made in the phase separation area but at considerable cost in time and money and to the detriment of other investigative areas. Only the pump/bubble separator failed in a manner necessitating redesign. Its failure was, however, due to its being operated above the temperature range for which it was designed. The basic electrolysis cell design was not changed.

  2. Carbon dioxide electrolysis with solid oxide electrolyte cells for oxygen recovery in life support systems

    NASA Technical Reports Server (NTRS)

    Isenberg, Arnold O.; Cusick, Robert J.

    1988-01-01

    The direct electrochemical reduction of carbon dioxide (CO2) is achieved without catalysts and at sufficiently high temperatures to avoid carbon formation. The tubular electrolysis cell consists of thin layers of anode, electrolyte, cathode and cell interconnection. The electrolyte is made from yttria-stabilized zirconia which is an oxygen ion conductor at elevated temperatures. Anode and cell interconnection materials are complex oxides and are electronic conductors. The cathode material is a composite metal-ceramic structure. Cell performance characteristics have been determined using varying feed gas compositions and degrees of electrochemical decomposition. Cell test data are used to project the performance of a three-person CO2-electrolysis breadboard system.

  3. [Laser Tuning Performance Testing and Optimization in TDLAS Oxygen Measuring Systems].

    PubMed

    He, Jun-feng; Hu, Jun; Kan, Rui-feng; Xu, Zhen-yu; Wang, Tao

    2015-03-01

    TDLAS (tunable diode laser absorption spectroscopy) technology, with its unmatched advantages such as high selectivity molecular spectra, fast response, high sensitivity, non-contact measuring, become the preferred scheme for combustion process diagnosis, and can be effectively used for oxygen measuring. DFB (distributed feedback) laser diode with its small size, low power consumption, long service life, narrow linewidth, tunable wavelength has become the main choice of the TDLAS system. Performance of laser tuning characteristics is a key factor restricting TDLAS's measuring performance. According to TDLAS oxygen measuring system's working requirements, a simple experimental method was used to test and analyze tuning characteristics such as wavelength current, power current and wavelength temperature of a 764 nm DFB laser diode in the system. Nonlinear distortion of tuning curves was obvious, which affects oxygen measuring accuracy. The laser spectra's characteristics such as narrow linewidth, high side mode suppression ratio and wide wavelength tuning range are obvious, while its wavelength-current tuning curve with a tuning rate of about 0.023 nm x mA(-1) is not strictly linear. The higher the temperature the greater the threshold current, the PI curve is not strictly linear either. Temperature tuning curve is of good linearity, temperature-wave-length tuning rate keeps constant of about 0.056 nm/DEG C. Temperature tuning nonlinearity can be improved by high temperature control accuracy, and current power nonlinearity can be improved by setting the reference light path. In order to solve the wavelength current tuning nonlinear problems, the method of DA controlling injection current was considered to compensate for non-linear wavelength current tuning according to DFB laser diode tuning mechanism and polynomial fitting of test results. In view of different type of lasers, this method needs only one polynomial fitting process before the system's initial work. The

  4. Testing and Oxygen Assessment Results for a Next Generation Extravehicular Activity Portable Life Support System Fan

    NASA Technical Reports Server (NTRS)

    Paul, Heather L.; Jennings, Mallory A.; Rivera, Fatonia L.; Martin, Devin

    2011-01-01

    NASA is designing a next generation Extravehicular Activity (EVA) Portable Life Support System (PLSS) for use in future surface exploration endeavors. To meet the new requirements for ventilation flow at nominal and buddy modes, a fan has been developed and tested. This paper summarizes the results of the performance and life cycle testing efforts conducted at the NASA Johnson Space Center. Additionally, oxygen compatibility assessment results from an evaluation conducted at White Sands Test Facility (WSTF) are provided, and lessons learned and future recommendations are outlined.

  5. A simplified CARS measurement system for rapid determination of temperature and oxygen concentration

    NASA Technical Reports Server (NTRS)

    Fujii, Shoichi

    1987-01-01

    A new spectroscopic concept for the rapid determination of temperature and oxygen concentration by CARS (Coherent Anti-Stokes Raman Spectroscopy) was described. The ratio of two spectral regions in the broadband Q-branch spectrum was detected by photomultipliers in a monochromator, which ratio depends on temperature and species concentration. The comparison of the measured data with theory was made using a flat flame burner and an electric furnace, with reasonable results. Various optical techniques for alignment were introduced including a highly efficient, stable dye oscillator. The combination of the spectroscopic concept and the optical techniques will make the CARS measurement system rapid in data processing and simple in optical parts.

  6. A Preliminary Study on the Toxic Combustion Products Testing of Polymers Used in High-Pressure Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Hshieh, Fu-Yu; Beeson, Harold D.

    2004-01-01

    One likely cause of polymer ignition in a high-pressure oxygen system is adiabatic-compression heating of polymers caused by pneumatic impact. Oxidative _ pyrolysis or combustion of polymers in a high-pressure oxygen system could generate toxic gases. This paper reports the preliminary results of toxic combustion product testing of selected polymers in a pneumatic-impact test system. Five polymers commonly used in high-pressure oxygen systems, Nylon 6/6, polychlorotrifluoroethylene (CTFE), polytetrafluoroethylene (PTFE), fluoroelastomer (Viton(TradeMark) A), and nitrile rubber (Buna N), were tested in a pneumatic-impact test system at 2500- or 3500-psia oxygen pressure. The polymers were ignited and burned, then combustion products were collected in a stainless-steel sample bottle and analyzed by GC/MS/IRD, GC/FID, and GC/Methanizer/FID. The results of adiabatic-compression tests show that combustion of hydrocarbon polymers, nitrogen-containing polymers, and halogenated polymers in high-pressure oxygen systems are relatively complete. Toxicity of the combustion product gas is presumably much lower than the combustion product gas generated from ambient-pressure oxygen (or air) environments. The NASA-Lewis equilibrium code was used to determine the composition of combustion product gas generated from a simulated, adiabatic-compression test of nine polymers. The results are presented and discussed.

  7. Conceptual design of a lunar oxygen pilot plant Lunar Base Systems Study (LBSS) task 4.2

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The primary objective was to develop conceptual designs of two pilot plants to produce oxygen from lunar materials. A lunar pilot plant will be used to generate engineering data necessary to support an optimum design of a larger scale production plant. Lunar oxygen would be of primary value as spacecraft propellant oxidizer. In addition, lunar oxygen would be useful for servicing nonregenerative fuel cell power systems, providing requirements for life support, and to make up oxygen losses from leakage and airlock cycling. Thirteen different lunar oxygen production methods are described. Hydrogen reduction of ilmenite and extraction of solar-wind hydrogen from bulk lunar soil were selected for conceptual design studies. Trades and sensitivity analyses were performed with these models.

  8. Integrated device for the measurement of systemic and local oxygen transport during physical exercise.

    PubMed

    Pollonini, Luca; Re, Rebecca; Simpson, Richard J; Dacso, Clifford C

    2012-01-01

    Current methods for monitoring exercise exertion rely upon heart rate monitors, which represent a crude and lagging indicator of conditioning. The rationale for the present study is that both systemic and local metabolic mechanisms are responsible for physical performance, and therefore they should be simultaneously quantified to achieve an objective assessment of human conditioning. We propose a compact, wearable near-infrared spectroscopy (NIRS) device integrated with electrocardiography (ECG) and photoplethysmography (PPG) to simultaneously assess the cardiovascular and local response to exercise. The system was tested on subjects performing a graded maximal exercise by comparing our readings with metabolic variables measured with respiratory gas analysis. We found strong correlations between local deoxyhemoglobin concentration [HHb], heart rate and oxygen uptake, as well as between oxyhemoglobin concentration [HbO(2)] and stroke volume. This study shows that combined NIRS, ECG and PPG measurements yield useful information to understand the interplay between systemic and local muscular responses to exercise.

  9. Solid polymer electrolyte water electrolysis system development. [to generate oxygen for manned space station applications

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Solid polymer electrolyte technology used in a water electrolysis system (WES) to generate oxygen and hydrogen for manned space station applications was investigated. A four-man rated, low pressure breadboard water electrolysis system with the necessary instrumentation and controls was fabricated and tested. A six man rated, high pressure, high temperature, advanced preprototype WES was developed. This configuration included the design and development of an advanced water electrolysis module, capable of operation at 400 psig and 200 F, and a dynamic phase separator/pump in place of a passive phase separator design. Evaluation of this system demonstrated the goal of safe, unattended automated operation at high pressure and high temperature with an accumulated gas generation time of over 1000 hours.

  10. Oxygen isotope systematics in an evolving geothermal system: Coso Hot Springs, California

    NASA Astrophysics Data System (ADS)

    Etzel, Thomas M.; Bowman, John R.; Moore, Joseph N.; Valley, John W.; Spicuzza, Michael J.; McCulloch, Jesse M.

    2017-01-01

    Oxygen isotope and clay mineralogy studies have been made on whole rock samples and feldspar separates from three wells along the high temperature West Flank of the Coso geothermal system, California. The reservoir rocks have experienced variable 18O/16O depletion, with δ18O values ranging from primary values of + 7.5‰ down to - 4.6‰. Spatial patterns of clay mineral distributions in the three wells are not closely correlated with the distributions expected from measured, pre-production temperature profiles, but do correlate with spatial patterns of 18O/16O depletion, indicating that the stability of clay minerals in the three wells is a function of fluid-rock interaction in addition to temperature. Detailed δ18O measurements in the three wells identify a limited number of localized intervals of extensive 18O/16O depletion. These intervals document localized zones of higher permeability in the geothermal system that have experienced significant fluid infiltration, water-rock interaction and oxygen isotopic exchange with the geothermal fluids. The local zones of maximum 18O/16O depletion in each well correspond closely with current hot water production zones. Most feldspar separates have measured δ18O values too high to have completely attained oxygen isotope exchange equilibrium with the reservoir fluid at pre-production temperatures. In general, the lower the δ18O value of the feldspar, the closer the feldspar approaches exchange equilibrium with the geothermal fluid. This correlation suggests that fracture-induced increases in permeability increase both fluid infiltration and the surface area of the host rock exposed to geothermal fluid, promoting fluid-rock interaction and oxygen isotope exchange. The two most 18O/16O-depleted feldspar samples have δ18O values too low to be in exchange equilibrium with the pre-production reservoir fluid at pre-production temperatures. These discrepancies suggest that the reservoir fluid in the West Flank of the Coso

  11. Development of a Portable Oxygen Monitoring System for Operations in the International Space Station Airlock

    NASA Technical Reports Server (NTRS)

    Graf, John

    2009-01-01

    NASA is currently engaged in an activity to facilitate effective operations on the International Space Station (ISS) after the Space Shuttle retires. Currently, the Space Shuttle delivers crew and cargo to and from ISS. The Space Shuttle provides the only large scale method of hardware return from ISS to the ground. Hardware that needs to be periodically repaired, refurbished, or recalibrated must come back from ISS on the Shuttle. One example of NASA flight hardware that is used on ISS and refurbished on the ground is the Compound Specific Analyzer for Oxygen (CSA-O2). The CSA-O2 is an electrochemical sensor that is used on orbit for about 12 months (depending on Shuttle launch schedules), then returned to the ground for sensor replacement. The shuttle is scheduled to retire in 2010, and the ISS is scheduled to operate until 2016. NASA needs a hand held sensor that measures oxygen in the ISS environment and has a 5-10 year service life. After conducting a survey of oxygen sensor systems, NASA selected a Tunable Diode Laser Absorption Spectrometer (TDLAS) as the method of measurement that best addresses the needs for ISS. These systems are compact, meet ISS accuracy requirements, and because they use spectroscopic techniques, the sensors are not consumed or altered after making a measurement. TDLAS systems have service life ratings of 5-10 years, based on the lifetime of the laser. NASA is engaged in modifying a commercially available sensor, the Vaisala OMT 355, for the ISS application. The Vaisala OMT 355 requires three significant modifications to meet ISS needs. The commercial sensor uses a wall mount power supply, and the ISS sensor needs to use a rechargeable battery as its source of power. The commercial sensor has a pressure correction setpoint: the sensor can be adjusted to operate at reduced pressure conditions, but the sensor does not self correct dynamically and automatically. The ISS sensor needs to operate in the airlock, and make accurate

  12. Development of a reflected optical fiber system for measuring oxygen saturation in an integrated artificial heart-lung system.

    PubMed

    Yasuda, Toshitaka; Saito, Tomohiko; Kihara, Tatsuya; Takatani, Setsuo; Funakubo, Akio

    2008-03-01

    The purpose of this study was to develop a blood oxygen saturation (OS) monitoring system for use with an integrated artificial heart-lung system (IAHLS). The OS monitoring system consists of two paired optical fiber probes (OFPs) and a measurement system. To investigate the effect of the OFP configuration and incident light wavelength on the relationship between OS and the reflectance ratio for wavelengths of 810 and 645 nm, we performed theoretical analyses of the relationship between OS and R810/R645 using a diffusion equation. The prototype OFP located on the blood outlet port of our IAHLS housing was evaluated using an in vitro test. An OS range of 65-100% was adjusted to supply oxygen and nitrogen gas to the IAHLS. The blood flow rate was maintained at 3 L/min by the rotational speed of an impeller in the IAHLS. The OS-corrected blood from the IAHLS was measured using a commercial gas analyzer. The correlation coefficients (r(2)) between the theoretical ratio of R810/R645 and OS, and between measured OS and the reflectance ratio of R810/R645 were 0.97 and 0.78, respectively. In conclusion, we confirmed that the development of this oximetry system is applicable for IAHLS.

  13. Bus application of oxygen-enrichment technology and diesel-electric hybrid systems

    SciTech Connect

    Sekar, R.R.; Marr, W.W.

    1993-10-01

    The amendments to the Clean Air Act (CAA) mandate very strict limits on particulate, smoke, and other emissions from city buses. The use of alternative fuels, such as compressed natural gas (CNG) or methanol, can help transit operators, such as the Chicago Transit Authority (CTA), meet the mandated limits. However, the capital investment needed to convert the fueling infrastructure and buses is large, as is the expense of training personnel. If a {open_quotes}clean diesel{close_quotes} bus can be implemented with the help of oxygen-enrichment technology or a diesel-electric hybrid system, this large investment could be postponed for many years. The Regional Transportation Authority (RTA) initiated this project to evaluate the possibility of applying these technologies to CTA buses. Argonne National Laboratory (ANL) conducted a limited number of engine tests and computer analyses and concluded that both concepts are practical and will help in a {open_quotes}clean diesel{close_quotes} bus that can meet the mandated limits of the CAA amendments. The oxygen enrichment of combustion air depends on the availability of a compact and economical membrane separator. Because the technology for this critical component is still under development, it is recommended that an actual bus demonstration be delayed until prototype membranes are available. The hybrid propulsion system is ready for the demonstration phase, and it is recommended that the CTA and RTA commence planning for a bus demonstration.

  14. Ammonium Removal by the Oxygen-Limited Autotrophic Nitrification-Denitrification System

    PubMed Central

    Kuai, Linping; Verstraete, Willy

    1998-01-01

    The present lab-scale research reveals the potential of implementation of an oxygen-limited autotrophic nitrification-denitrification (OLAND) system with normal nitrifying sludge as the biocatalyst for the removal of nitrogen from nitrogen-rich wastewater in one step. In a sequential batch reactor, synthetic wastewater containing 1 g of NH4+-N liter−1 and minerals was treated. Oxygen supply to the reactor was double-controlled with a pH controller and a timer. At a volumetric loading rate (Bv) of 0.13 g of NH4+-N liter−1 day−1, about 22% of the fed NH4+-N was converted to NO2−-N or NO3−-N, 38% remained as NH4+-N, and the other 40% was removed mainly as N2. The specific removal rate of nitrogen was on the order of 50 mg of N liter−1 day−1, corresponding to 16 mg of N g of volatile suspended solids−1 day−1. The microorganisms which catalyzed the OLAND process are assumed to be normal nitrifiers dominated by ammonium oxidizers. The loss of nitrogen in the OLAND system is presumed to occur via the oxidation of NH4+ to N2 with NO2− as the electron acceptor. Hydroxylamine stimulated the removal of NH4+ and NO2−. Hydroxylamine oxidoreductase (HAO) or an HAO-related enzyme might be responsible for the loss of nitrogen. PMID:9797314

  15. Replacement of HCFC-225 Solvent for Cleaning NASA Propulsion Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Lowrey, Nikki M.; Mitchell, Mark A.

    2015-01-01

    Since the 1990's, when the Class I Ozone Depleting Substance (ODS) chlorofluorocarbon-113 (CFC-113) was banned, NASA's propulsion test facilities at Marshall Space Flight Center (MSFC) and Stennis Space Center (SSC) have relied upon hydrochlorofluorocarbon-225 (HCFC-225) to safely clean and verify the cleanliness of large scale propulsion oxygen systems. Effective January 1, 2015, the production, import, export, and new use of HCFC-225, a Class II ODS, was prohibited by the Clean Air Act. In 2012 through 2014, leveraging resources from both NASA and the Defense Logistics Agency - Aviation Hazardous Minimization and Green Products Branch, test labs at MSFC, SSC, and Johnson Space Center's White Sands Test Facility (WSTF) collaborated to seek out, test, and qualify a replacement for HCFC-225 that is both an effective cleaner and safe for use with oxygen systems. This presentation summarizes the tests performed, results, and lessons learned. It also demonstrates the benefits of cross-agency collaboration in a time of limited resources.

  16. Design and test status for life support applications of SPE oxygen generation systems. [Solid Polymer Electrolyte

    NASA Technical Reports Server (NTRS)

    Titterington, W. A.; Erickson, A. C.

    1975-01-01

    An advanced six-man rated oxygen generation system has been fabricated and tested as part of a NASA/JSC technology development program for a long lived, manned spacecraft life support system. Details of the design and tests results are presented. The system is based on the Solid Polymer Electrolyte (SPE) water electrolysis technology and its nominal operating conditions are 2760 kN/sq m (400 psia) and 355 K (180 F) with an electrolysis module current density capability up to 350 mA/sq cm (326 ASF). The system is centered on a 13-cell SPE water electrolysis module having a single cell active area of 214 sq cm (33 sq in) and it incorporates instrumentation and controls for single pushbutton automatic startup/shutdown, component fault detection and isolation, and self-contained sensors and controls for automatic safe emergency shutdown. The system has been tested in both the orbital cyclic and continuous mode of operation. Various parametric tests have been completed to define the system capability for potential application in spacecraft environmental systems.

  17. Integrated Pressure-Fed Liquid Oxygen / Methane Propulsion Systems - Morpheus Experience, MARE, and Future Applications

    NASA Technical Reports Server (NTRS)

    Hurlbert, Eric; Morehead, Robert; Melcher, John C.; Atwell, Matt

    2016-01-01

    An integrated liquid oxygen (LOx) and methane propulsion system where common propellants are fed to the reaction control system and main engines offers advantages in performance, simplicity, reliability, and reusability. LOx/Methane provides new capabilities to use propellants that are manufactured on the Mars surface for ascent return and to integrate with power and life support systems. The clean burning, non-toxic, high vapor pressure propellants provide significant advantages for reliable ignition in a space vacuum, and for reliable safing or purging of a space-based vehicle. The NASA Advanced Exploration Systems (AES) Morpheus lander demonstrated many of these key attributes as it completed over 65 tests including 15 flights through 2014. Morpheus is a prototype of LOx/Methane propellant lander vehicle with a fully integrated propulsion system. The Morpheus lander flight demonstrations led to the proposal to use LOx/Methane for a Discovery class mission, named Moon Aging Regolith Experiment (MARE) to land an in-situ science payload for Southwest Research Institute on the Lunar surface. Lox/Methane is extensible to human spacecraft for many transportation elements of a Mars architecture. This paper discusses LOx/Methane propulsion systems in regards to trade studies, the Morpheus project experience, the MARE NAVIS (NASA Autonomous Vehicle for In-situ Science) lander, and future possible applications. The paper also discusses technology research and development needs for Lox/Methane propulsion systems.

  18. Laser-induced contamination of space borne laser systems: impact of organic contamination and mitigation by oxygen

    NASA Astrophysics Data System (ADS)

    Hippler, M.; Wagner, P.; Schroeder, H.; Riede, W.

    2016-09-01

    Laser-induced contamination (LIC) is still a major risk for space based laser systems. In this paper the mitigation of LIC by oxygen is investigated. Tests were performed with a pulsed laser at 355 nm. The partial pressure of the contamination material was in the range of 10-5 -10-4 mbar. The mitigation effect showed a threshold behavior concerning the ratio between contamination and oxygen pressure. Also a cleaning effect was successfully demonstrated: previously created depositions were completely removed by irradiation at several tens Pa oxygen pressure without any remaining degradation of the optical surface.

  19. Computation of Kinetics for the Hydrogen/Oxygen System Using the Thermodynamic Method

    NASA Technical Reports Server (NTRS)

    Marek, C. John

    1996-01-01

    A new method for predicting chemical rate constants using thermodynamics has been applied to the hydrogen/oxygen system. This method is based on using the gradient of the Gibbs free energy and a single proportionality constant D to determine the kinetic rate constants. Using this method the rate constants for any gas phase reaction can be computed from thermodynamic properties. A modified reaction set for the H/O system is determined. A11 of the third body efficiencies M are taken to be unity. Good agreement was obtained between the thermodynamic method and the experimental shock tube data. In addition, the hydrogen bromide experimental data presented in previous work is recomputed with M's of unity.

  20. International Space Station United States Orbital Segment Oxygen Generation System On-Orbit Operational Experience

    NASA Technical Reports Server (NTRS)

    Erickson, Robert J.; Howe, John, Jr.; Kulp, Galen W.; VanKeuren, Steven P.

    2008-01-01

    The International Space Station (ISS) United States Orbital Segment (USOS) Oxygen Generation System (OGS) was originally intended to be installed in ISS Node 3. The OGS rack delivery was accelerated, and it was launched to ISS in July of 2006 and installed in the US Laboratory Module. Various modification kits were installed to provide its interfaces, and the OGS was first activated in July of 2007 for 15 hours, In October of 2007 it was again activated for 76 hours with varied production rates and day/night cycling. Operational time in each instance was limited by the quantity of feedwater in a Payload Water Reservoir (PWR) bag. Feedwater will be provided by PWR bag until the USOS Water Recovery System (WRS) is delivered to SS in fall of 2008. This paper will discuss operating experience and characteristics of the OGS, as well as operational issues and their resolution.

  1. Investigation of singlet oxygen generation in Vit C-Cu2+ -LDL system by chemiluminescence method

    NASA Astrophysics Data System (ADS)

    Wang, Juan; Xing, Da; Tan, Shici; Tang, Yonghong; He, Yonghong

    2002-04-01

    In this study, by chemiluminescence method using a Cypridina luciferin analog, 2-methyl-6-(p-methoxyphenyl)-3,7- dihydroimidazo[1,2-a]pyrazin-3-one (MCLA), as a selective and sensitive chemiluminescence probe, singlet oxygen (1O2) formation was observed in the vit C- LDL-Cu2+ reaction system. Another experimental evidence for the generation of 1O2 was the quenching effect of sodium azide (NaN3) on vit C-induced chemiluminescence in the reaction mixture of LDL- Cu2+-MCLA. Analysis based on the experimental results indicated the plausible reaction mechanism is that vit C converts Cu2+ to its reduced state and vit C becomes vit C radical itself, thereby stimulating the formation of peroxyl radicals, and bimolecular reaction of peroxyl radicals results in 1O2 production in the above systems.

  2. Evolution of oxygen secretion in fishes and the emergence of a complex physiological system.

    PubMed

    Berenbrink, Michael; Koldkjaer, Pia; Kepp, Oliver; Cossins, Andrew R

    2005-03-18

    We have reconstructed the events that led to the evolution of a key physiological innovation underpinning the large adaptive radiation of fishes, namely their unique ability to secrete molecular oxygen (O2). We show that O2 secretion into the swimbladder evolved some 100 million years after another O2-secreting system in the eye. We unravel the likely sequence in which the functional components of both systems evolved. These components include ocular and swimbladder countercurrent exchangers, the Bohr and Root effects, the buffering power and surface histidine content of hemoglobins, and red blood cell Na+/H+ exchange activity. Our synthesis reveals the dynamics of gains and losses of these multiple traits over time, accounting for part of the huge diversity of form and function in living fishes.

  3. Parallel electrochemical treatment system and application for identifying acid-stable oxygen evolution electrocatalysts.

    PubMed

    Jones, Ryan J R; Shinde, Aniketa; Guevarra, Dan; Xiang, Chengxiang; Haber, Joel A; Jin, Jian; Gregoire, John M

    2015-02-09

    Many energy technologies require electrochemical stability or preactivation of functional materials. Due to the long experiment duration required for either electrochemical preactivation or evaluation of operational stability, parallel screening is required to enable high throughput experimentation. Imposing operational electrochemical conditions to a library of materials in parallel creates several opportunities for experimental artifacts. We discuss the electrochemical engineering principles and operational parameters that mitigate artifacts in the parallel electrochemical treatment system. We also demonstrate the effects of resistive losses within the planar working electrode through a combination of finite element modeling and illustrative experiments. Operation of the parallel-plate, membrane-separated electrochemical treatment system is demonstrated by exposing a composition library of mixed-metal oxides to oxygen evolution conditions in 1 M sulfuric acid for 2 h. This application is particularly important because the electrolysis and photoelectrolysis of water are promising future energy technologies inhibited by the lack of highly active, acid-stable catalysts containing only earth abundant elements.

  4. [Changes in the oxidant-antioxidant system activity in patients with hepatic failure treated with hyperbaric oxygenation and actoprotectors].

    PubMed

    Lakhin, R E; Belozerova, L A; Maksimets, V A; Romanov, D M

    1999-01-01

    Effects of hyperbaric oxygenation, bemitil, and solcoseryl used in preoperative treatment of patients with hepatic failure on the oxidant-antioxidant system are studied. Lipid peroxidation (LPO) was assessed from changes in the levels of malonic dialdehyde and diene conjugate and the antioxidant system from the number of SH-groups. Hyperbaric oxygenation led to activation of LPO processes. Bemitil decreased the intensity of LPO by extending the potentialities of the antioxidant system. Antioxidant properties of solcoseryl were not realized through the thiol buffer of the antioxidant system. Only a course of treatment with this drug brings about a stable effect.

  5. Ultra-sensitive optical oxygen sensors for characterisation of nearly anoxic systems

    PubMed Central

    Lehner, Philipp; Staudinger, Christoph; Borisov, Sergey M.; Klimant, Ingo

    2014-01-01

    Oxygen quantification in trace amounts is essential in many fields of science and technology. Optical oxygen sensors proved invaluable tools for oxygen measurements in a broad concentration range but until now neither optical nor electrochemical oxygen sensors were able to quantify oxygen in the sub-nanomolar concentration range. Herein we present new optical oxygen sensing materials with unmatched sensitivity. They rely on the combination of ultra-long decaying (several hundred milliseconds lifetime) phosphorescent boron- and aluminium-chelates and highly oxygen-permeable and chemically stable perfluorinated polymers. The sensitivity of the new sensors is improved up to 20-fold compared to state-of-the-art analogues. The limits of detection are as low as 5 parts per billion, volume in gas phase under atmospheric pressure or 7 picomolar in solution. The sensors enable completely new applications for monitoring of oxygen in previously inaccessible concentration ranges. PMID:25042041

  6. Effect of Operating Parameters on a Dual-Stage High Velocity Oxygen Fuel Thermal Spray System

    NASA Astrophysics Data System (ADS)

    Khan, Mohammed N.; Shamim, Tariq

    2014-08-01

    High velocity oxygen fuel (HVOF) thermal spray systems are being used to apply coatings to prevent surface degradation. The coatings of temperature sensitive materials such as titanium and copper, which have very low melting points, cannot be applied using a single-stage HVOF system. Therefore, a dual-stage HVOF system has been introduced and modeled computationally. The dual-spray system provides an easy control of particle oxidation by introducing a mixing chamber. In addition to the materials being sprayed, the thermal spray coating quality depends to a large extent on flow behavior of reacting gases and the particle dynamics. The present study investigates the influence of various operating parameters on the performance of a dual-stage thermal spray gun. The objective is to develop a predictive understanding of various parameters. The gas flow field and the free jet are modeled by considering the conservation of mass, momentum, and energy with the turbulence and the equilibrium combustion sub models. The particle phase is decoupled from the gas phase due to very low particle volume fractions. The results demonstrate the advantage of a dual-stage system over a single-stage system especially for the deposition of temperature sensitive materials.

  7. Four Components of the Conjugated Redox System in Organisms: Carbon, Nitrogen, Sulfur, Oxygen.

    PubMed

    Tereshina, E V; Laskavy, V N; Ivanenko, S I

    2015-09-01

    C1 compounds participate in various metabolic processes and regulations including DNA methylation. Formaldehyde (FA), a product of methyl group oxidation, is highly cytotoxic. In the cell, there are two pathways of its utilization: assimilation and oxidation. Formaldehyde displays cytotoxicity, and therefore its oxidation is considered as detoxification. The sensitivity to the threshold concentration of FA we regard as an indication of its major role in biosystem functioning. A model of a three-component conjugated redox system is proposed in which the methyl group oxidation pathway is an archaic and conservative donor of protons and electrons, the reduction of O2 serves as an acceptor, and the arginine amino group is used for production of both urea and nitric oxide (the donor and acceptor, respectively). The fourth component of the redox system is glutathione, which maintains redox balance. The three-level system of proton donors includes the oxidation of a methyl group (first level), the oxidation of acetate in mitochondria (second level), and glucose catabolism in the pentose phosphate pathway (third level). The whole redox system is united by the sulfhydryl groups of cysteines, glutathione, thioredoxin, and α-lipoic acid. The central regulatory role in this redox system belongs to glutathione-dependent formaldehyde dehydrogenase, which controls FA binding with tetrahydrofolic acid, arginine methylation, and denitrosation of sulfhydryl groups. The conjugated redox system was formed during evolution as a union of separate redox cycles of carbon, nitrogen, sulfur, and oxygen.

  8. A luminol-based micro-flow-injection electrochemiluminescent system to determine reactive oxygen species.

    PubMed

    Chen, Ming; Wei, Xiuhua; Tu, Yifeng

    2011-09-15

    A flow injection analysis (FIA) system with electrochemiluminescent (ECL) detection has been established. Based on a specially designed flow-through ECL cell with a very simple structure, the system possesses rapid response and high sensitivity. With luminol as the ECL reagent, the response of hydrogen peroxide (H(2)O(2)) was investigated on the developed FIA-ECL system. After optimizing the experimental conditions, such as the electric parameters, the buffer condition and the flow rate, it was demonstrated that the developed FIA-ECL system works well for quantified assays. Compared with reported works, the present results indicate that the developed FIA-ECL system has the lowest limit of detection (S/N=3) of 3.0×10(-9) mol/L for H(2)O(2), which is equal to the level of chemiluminescence (CL). The developed system was successfully used to monitor the yield of reactive oxygen species (ROSs) in water vapour during the work of an ultrasonic humidifier with H(2)O(2) as index. And the amount of ROSs in some other real samples, including tap water, drinking water and river water was detected with recoveries from 92.0% to 106%.

  9. Reference concepts for a space-based hydrogen-oxygen combustion, turboalternator, burst power system

    SciTech Connect

    Edenburn, M.W.

    1990-07-01

    This report describes reference concepts for a hydrogen-oxygen combustion, turboalternator power system that supplies power during battle engagement to a space-based, ballistic missile defense platform. All of the concepts are open''; that is, they exhaust hydrogen or a mixture of hydrogen and water vapor into space. We considered the situation where hydrogen is presumed to be free to the power system because it is also needed to cool the platform's weapon and the situation where hydrogen is not free and its mass must be added to that of the power system. We also considered the situation where water vapor is an acceptable exhaust and the situation where it is not. The combination of these two sets of situations required four different power generation systems, and this report describes each, suggests parameter values, and estimates masses for each of the four. These reference concepts are expected to serve as a baseline'' to which other types of power systems can be compared, and they are expected to help guide technology development efforts in that they suggest parameter value ranges that will lead to optimum system designs. 7 refs., 18 figs., 5 tabs.

  10. Procedure for the selection of materials for use in oxygen systems at the John F. Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Bryan, Coleman J.; Olsen, Melvin G.

    1988-01-01

    This paper describes tests used at the John F. Kennedy Space Center (KSC) in the material selection procedure for evaluating materials suitable for use in oxygen systems. Special attention is given to the basic selection criteria for materials used in oxygen enriched environments. The flow chart for the material selection procedure is presented, and information that must be supplied by vendors requesting batch/lot certification support from KSC is given.

  11. Use of a High-Flow Oxygen Delivery System in a Critically Ill Patient with Dementia

    DTIC Science & Technology

    2008-12-01

    a high oxygen concentration. Key words: high-flow oxygen, palliative care , hypoxemia. [Respir Care 2008;53(12):1739–1743] Introduction We have...The use of supplemental oxygen to relieve dyspnea in palliative care is controversial. It is not clear that supple- mental oxygen actually reduces...rior to conventional nasal cannula and equivalent to nasal continuous positive airway pressure in pediatric patients. In neonatal intensive care unit

  12. Extension of Central Nervous and Visual System Oxygen Tolerance in Physical Work.

    DTIC Science & Technology

    1990-12-31

    possible that patterns of intermittent oxygen exposure that are currently under investigation for practical and effective extension of oxygen tolerance in...it has not been practical to identify susceptible individuals in advance. Most previous studies of exercise effects on CNS oxygen tolerance have...a reliable, preconvulsive index of CNS or visual oxygen toxicity was an absolute handicap to investigation of intermittent hyperoxia as a practical

  13. Effects of diving and oxygen on autonomic nervous system and cerebral blood flow.

    PubMed

    Winklewski, Pawel J; Kot, Jacek; Frydrychowski, Andrzej F; Nuckowska, Magdalena K; Tkachenko, Yurii

    2013-09-01

    Recreational scuba diving is a popular leisure activity with the number of divers reaching several millions worldwide. Scuba diving represents a huge challenge for integrative physiology. In mammalian evolution, physiological reflexes developed to deal with lack of oxygen, rather than with an excess, which makes adaptations to scuba diving more difficult to describe and understand than those associated with breath-hold diving. The underwater environment significantly limits the use of equipment to register the organism's functions, so, in most instances, scientific theories are built on experiments that model real diving to some extent, like hyperbaric exposures, dive reflexes or water immersion. The aim of this review is to summarise the current knowledge related to the influence exerted by physiological conditions specific to diving on the autonomic nervous system and cerebral blood flow. The main factors regulating cerebral blood flow during scuba diving are discussed as follows: 1) increased oxygen partial pressure; 2) immersion-related trigemino-cardiac reflexes and 3) exposure to cold, exercise and stress. Also discussed are the potential mechanisms associated with immersion pulmonary oedema.

  14. [Dangerous complication of transtracheal oxygen therapy with the SCOOP(R) system].

    PubMed

    Rothe, T B; Frey, J G; Ciobanu, T D; Karrer, W

    1996-10-01

    A portable oxygen system in combination with transtracheal O2 delivery (SCOOP(R)) permits patients with respiratory failure optimal mobility and facilitates longterm oxygen therapy. This report describes a 70 year old female with COPD that developed acute respiratory distress 18 days after inserting PRESCOOP(R) and 11 days after changing to SCOOP 1 catheter. Catheter stripping had not revealed any pathology. Flexible bronchoscopy showed a mucus ball at the catheter tip leading to a 80% stenosis of the trachea. Trials to remove the ball with forceps and a loop were not successful until a rigid bronchoscop was inserted. Up to 10% of patients develop mucus ball formation with SCOOP 1 catheter which remains in situ for 6 weeks. In patients with high risk of mucus formation (high O2 flow, viscous mucus, low FEV1) the manufacturers of SCOOP recommend catheter stripping. We consider a control bronchoscopy being safer 1 week after changing from PRESCOOP to SCOOP because one patient has been reported to have died of this complication and our patient has developed a near fatal situation.

  15. Nitric oxide and reactive oxygen species are required for systemic acquired resistance in plants.

    PubMed

    El-Shetehy, Mohamed; Wang, Caixia; Shine, M B; Yu, Keshun; Kachroo, Aardra; Kachroo, Pradeep

    2015-01-01

    Systemic acquired resistance (SAR) is a form of broad-spectrum disease resistance that is induced in response to primary infection and that protects uninfected portions of the plant against secondary infections by related or unrelated pathogens. SAR is associated with an increase in chemical signals that operate in a collective manner to confer protection against secondary infections. These include, the phytohormone salicylic acid (SA), glycerol-3-phosphate (G3P), azelaic acid (AzA) and more recently identified signals nitric oxide (NO) and reactive oxygen species (ROS). NO, ROS, AzA and G3P function in the same branch of the SAR pathway, and in parallel to the SA-regulated branch. NO and ROS function upstream of AzA/G3P and different reactive oxygen species functions in an additive manner to mediate chemical cleavage of the C9 double bond on C18 unsaturated fatty acids to generate AzA. The parallel and additive functioning of various chemical signals provides important new insights in the overlapping pathways leading to SAR.

  16. The Ketogenic Diet and Hyperbaric Oxygen Therapy Prolong Survival in Mice with Systemic Metastatic Cancer

    PubMed Central

    Poff, Angela M.; Ari, Csilla; Seyfried, Thomas N.; D’Agostino, Dominic P.

    2013-01-01

    Introduction Abnormal cancer metabolism creates a glycolytic-dependency which can be exploited by lowering glucose availability to the tumor. The ketogenic diet (KD) is a low carbohydrate, high fat diet which decreases blood glucose and elevates blood ketones and has been shown to slow cancer progression in animals and humans. Abnormal tumor vasculature creates hypoxic pockets which promote cancer progression and further increase the glycolytic-dependency of cancers. Hyperbaric oxygen therapy (HBO2T) saturates tumors with oxygen, reversing the cancer promoting effects of tumor hypoxia. Since these non-toxic therapies exploit overlapping metabolic deficiencies of cancer, we tested their combined effects on cancer progression in a natural model of metastatic disease. Methods We used the firefly luciferase-tagged VM-M3 mouse model of metastatic cancer to compare tumor progression and survival in mice fed standard or KD ad libitum with or without HBO2T (2.5 ATM absolute, 90 min, 3x/week). Tumor growth was monitored by in vivo bioluminescent imaging. Results KD alone significantly decreased blood glucose, slowed tumor growth, and increased mean survival time by 56.7% in mice with systemic metastatic cancer. While HBO2T alone did not influence cancer progression, combining the KD with HBO2T elicited a significant decrease in blood glucose, tumor growth rate, and 77.9% increase in mean survival time compared to controls. Conclusions KD and HBO2T produce significant anti-cancer effects when combined in a natural model of systemic metastatic cancer. Our evidence suggests that these therapies should be further investigated as potential non-toxic treatments or adjuvant therapies to standard care for patients with systemic metastatic disease. PMID:23755243

  17. Liquid Methane/Liquid Oxygen Propellant Conditioning Feed System (PCFS) Test Rigs

    NASA Technical Reports Server (NTRS)

    Skaff, A.; Grasl, S.; Nguyen, C.; Hockenberry S.; Schubert, J.; Arrington, L.; Vasek, T.

    2008-01-01

    As part of their Propulsion and Cryogenic Advanced Development (PCAD) program, NASA has embarked upon an effort to develop chemical rocket engines which utilize non-toxic, cryogenic propellants such as liquid oxygen (LO2) and liquid methane (LCH4). This effort includes the development and testing of a 100 lbf Reaction Control Engine (RCE) that will be used to evaluate the performance of a LO2/LCH4 rocket engine over a broad range of propellant temperatures and pressures. This testing will take place at NASA-Glenn Research Center's (GRC) Research Combustion Laboratory (RCL) test facility in Cleveland, OH, and is currently scheduled to begin in late 2008. While the initial tests will be performed at sea level, follow-on testing will be performed at NASA-GRC's Altitude Combustion Stand (ACS) for altitude testing. In support of these tests, Sierra Lobo, Inc. (SLI) has designed, developed, and fabricated two separate portable propellant feed systems under the Propellant Conditioning and Feed System (PCFS) task: one system for LCH4, and one for LO2. These systems will be capable of supplying propellants over a large range of conditions from highly densified to several hundred pounds per square inch (psi) saturated. This paper presents the details of the PCFS design and explores the full capability of these propellant feed systems.

  18. Oxygenation and perfusion monitoring with a hyperspectral camera system for chemical based tissue analysis of skin and organs.

    PubMed

    Holmer, Amadeus; Tetschke, Florian; Marotz, Jörg; Malberg, Hagen; Markgraf, Wenke; Thiele, Christine; Kulcke, Axel

    2016-11-01

    The monitoring of free flaps, free transplants or organs for transplantation still poses a problem in medicine. Available systems for the measurement of perfusion and oxygenation can only perform localized measurements and usually need contact with the tissue. Contact free hyperspectral imaging and near-infrared spectroscopy (NIRS) for the analysis of tissue oxygenation and perfusion have been used in many scientific studies with good results. But up to now the clinical and scientific application of this technology has been hindered by the lack of hyperspectral measurement systems usable in clinical practice. We will introduce the application of a new hyperspectral camera system for the quick and robust recording of remission spectra in the combined VIS and NIR spectral range with high spectral and spatial resolution. This new system can be applied for the clinical monitoring of free flaps and organs providing high quality oxygenation and perfusion images.

  19. Oxygen transport membrane system and method for transferring heat to catalytic/process reactors

    DOEpatents

    Kelly, Sean M; Kromer, Brian R; Litwin, Michael M; Rosen, Lee J; Christie, Gervase Maxwell; Wilson, Jamie R; Kosowski, Lawrence W; Robinson, Charles

    2014-01-07

    A method and apparatus for producing heat used in a synthesis gas production is provided. The disclosed method and apparatus include a plurality of tubular oxygen transport membrane elements adapted to separate oxygen from an oxygen containing stream contacting the retentate side of the membrane elements. The permeated oxygen is combusted with a hydrogen containing synthesis gas stream contacting the permeate side of the tubular oxygen transport membrane elements thereby generating a reaction product stream and radiant heat. The present method and apparatus also includes at least one catalytic reactor containing a catalyst to promote the stream reforming reaction wherein the catalytic reactor is surrounded by the plurality of tubular oxygen transport membrane elements. The view factor between the catalytic reactor and the plurality of tubular oxygen transport membrane elements radiating heat to the catalytic reactor is greater than or equal to 0.5.

  20. Oxygen transport membrane system and method for transferring heat to catalytic/process reactors

    DOEpatents

    Kelly, Sean M.; Kromer, Brian R.; Litwin, Michael M.; Rosen, Lee J.; Christie, Gervase Maxwell; Wilson, Jamie R.; Kosowski, Lawrence W.; Robinson, Charles

    2016-01-19

    A method and apparatus for producing heat used in a synthesis gas production process is provided. The disclosed method and apparatus include a plurality of tubular oxygen transport membrane elements adapted to separate oxygen from an oxygen containing stream contacting the retentate side of the membrane elements. The permeated oxygen is combusted with a hydrogen containing synthesis gas stream contacting the permeate side of the tubular oxygen transport membrane elements thereby generating a reaction product stream and radiant heat. The present method and apparatus also includes at least one catalytic reactor containing a catalyst to promote the steam reforming reaction wherein the catalytic reactor is surrounded by the plurality of tubular oxygen transport membrane elements. The view factor between the catalytic reactor and the plurality of tubular oxygen transport membrane elements radiating heat to the catalytic reactor is greater than or equal to 0.5

  1. Investigation of packaging systems for shelled walnuts based on oxygen absorbers.

    PubMed

    Jensen, Pernille N; Sørensen, Gitte; Brockhoff, Per; Bertelsen, Grete

    2003-08-13

    Storage of nuts at a high oxygen concentration results in rancid nuts whereas storage at a low oxygen concentration results in fine-tasting nuts. During a 13 month experiment, packaging of walnuts with an oxygen absorber was compared to packaging in nitrogen or atmospheric air. At the same time, the effects of oxygen permeability of the packaging material and storage temperature (11 and 21 degrees C) were investigated by determination of hexanal and rancid taste of the walnuts. The optimal storage condition for walnuts is at 11 degrees C or lower, eventually combined with an oxygen absorber. However, without chilled storage and use of an oxygen absorber, it is possible to obtain an acceptable quality of walnuts with a packaging material having a very low oxygen permeability (e.g., laminate with EVOH) combined with nitrogen flushing. The results also revealed that the development of hexanal during time can be described by a second-order polynomial regression model.

  2. Optical methods and systems for detecting a constituent in a gas containing oxygen in harsh environments

    SciTech Connect

    Carpenter, Michael A.; Sirinakis, George

    2011-01-04

    A method for detecting a gas phase constituent such as carbon monoxide, nitrogen dioxide, hydrogen, or hydrocarbons in a gas comprising oxygen such as air, includes providing a sensing material or film having a metal embedded in a catalytically active matrix such as gold embedded in a yttria stabilized zirconia (YSZ) matrix. The method may include annealing the sensing material at about 900.degree. C., exposing the sensing material and gas to a temperature above 400.degree. C., projecting light onto the sensing material, and detecting a change in the absorption spectrum of the sensing material due to the exposure of the sensing material to the gas in air at the temperature which causes a chemical reaction in the sensing material compared to the absorption spectrum of the sensing material in the absence of the gas. Systems employing such a method are also disclosed.

  3. Regulation of signal transduction by reactive oxygen species in the cardiovascular system.

    PubMed

    Brown, David I; Griendling, Kathy K

    2015-01-30

    Oxidative stress has long been implicated in cardiovascular disease, but more recently, the role of reactive oxygen species (ROS) in normal physiological signaling has been elucidated. Signaling pathways modulated by ROS are complex and compartmentalized, and we are only beginning to identify the molecular modifications of specific targets. Here, we review the current literature on ROS signaling in the cardiovascular system, focusing on the role of ROS in normal physiology and how dysregulation of signaling circuits contributes to cardiovascular diseases, including atherosclerosis, ischemia-reperfusion injury, cardiomyopathy, and heart failure. In particular, we consider how ROS modulate signaling pathways related to phenotypic modulation, migration and adhesion, contractility, proliferation and hypertrophy, angiogenesis, endoplasmic reticulum stress, apoptosis, and senescence. Understanding the specific targets of ROS may guide the development of the next generation of ROS-modifying therapies to reduce morbidity and mortality associated with oxidative stress.

  4. Interhospital Transport System for Critically Ill Patients: Mobile Extracorporeal Membrane Oxygenation without a Ventilator

    PubMed Central

    Yeo, Hye Ju; Cho, Woo Hyun; Park, Jong Myung; Kim, Dohyung

    2017-01-01

    Background Extracorporeal membrane oxygenation (ECMO) has been successfully used as a method for the interhospital transportation of critically ill patients. In South Korea, a well-established ECMO interhospital transport system is lacking due to limited resources. We developed a simplified ECMO transport system without mechanical ventilation for use by public emergency medical services. Methods Eighteen patients utilized our ECMO transport system from December 2011 to September 2015. We retrospectively analyzed the indications for ECMO, the patient status during transport, and the patient outcomes. Results All transport was conducted on the ground by ambulance. The distances covered ranged from 26 to 408 km (mean, 65.9±88.1 km) and the average transport time was 56.1±57.3 minutes (range, 30 to 280 minutes). All patients were transported without adverse events. After transport, 4 patients (22.2%) underwent lung transplantation because of interstitial lung disease. Eight patients who had severe acute respiratory distress syndrome showed recovery of heart and lung function after ECMO therapy. A total of 13 patients (70.6%) were successfully taken off ECMO, and 11 patients (61.1%) survived. Conclusion Our ECMO transport system without mechanical ventilation can be considered a safe and useful method for interhospital transport and could be a good alternative option for ECMO transport in Korean hospitals with limited resources. PMID:28180097

  5. A Brief Study on Toxic Combustion Products of the Polymers Used in High-Pressure Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Hshieh, Fu-Yu; Beeson, Harold D.

    2005-01-01

    One likely cause of polymer ignition in a high-pressure oxygen system is the adiabatic-compression heating of polymers caused by pneumatic impact. Oxidative pyrolysis or combustion of polymers in a high-pressure oxygen system could generate toxic gases. This paper investigates the feasibility of using the NASA pneumatic-impact system to conduct adiabatic-compression combustion tests and determines the toxic combustion products produced from the burning of five selected polymers. Five polymers commonly used in high-pressure oxygen systems, Zytel(Registered TradeMark) 42 (Nylon 6/6), Buna N (nitrile rubber), Witon(Registered TradeMark) A (copolymer of vinylidene fluoride and hexafluoropropylene), Neoflon(Registered TradeMark) (polychlorotrifluoroethylene), and Teflon(Registered TradeMark) (polytetrafluoroethylene), were tested in the NASA pneumatic-impact test system at 17.2-MPa oxygen pressure. The polymers were ignited and burned; combustion products were collected in a stainless-steel sample bottle and analyzed using various methods. The results show that the NASA pneumatic-impact system is an appropriate test system to conduct adiabatic-compression combustion tests and to collect combustion products for further chemical analysis. The composition of the combustion product gas generated from burning the five selected polymers are presented and discussed.

  6. From system to organ to cell: oxygenation and perfusion measurement in anesthesia and critical care.

    PubMed

    Schober, Patrick; Schwarte, Lothar A

    2012-08-01

    Maintenance or restoration of adequate tissue oxygenation is a main goal of anesthesiologic and intensive care patient management. Pathophysiological disturbances which interfere with aerobic metabolism may occur at any stage in the oxygen cascade from atmospheric gas to the mitochondria, and there is no single monitoring modality that allows comprehensive determination of "the oxygenation". To facilitate early detection of tissue hypoxia (or hyperoxia) and to allow a goal directed therapy targeted at the underlying problem, the anesthesiologist and intensive care physician require a thorough understanding of the numerous determinants that influence cellular oxygenation. This article reviews the basic physiology of oxygen uptake and delivery to tissues as well as the options to monitor determinants of oxygenation at different stages from the alveolus to the cell.

  7. Effect of oxygen on reaction mechanisms of interface formation in the Cu-Ti-O/sapphire system

    SciTech Connect

    Camargo, P.R.C.; Liu, S.; Edwards, G.R.

    1994-12-31

    It has been reported that in active metal brazing of sapphire using titanium as the active element, titanium segregates to the sapphire-metal interface and reduces the sapphire, forming an intermediate oxide interphase region. In this work, the effect of oxygen on the reaction mechanisms of interface formation by active metal brazing in the Cu-Ti-O/sapphire (single crystal) system was investigated. Spectroscopically pure copper and titanium were used to prepare, in-situ, copper alloys with two different levels of titanium (1 and 2 at.pct). Three brazing temperatures were investigated: 1100, 1150, and 1200{degrees}C. A scavenging system using copper and niobium as getter materials was used to produce atmospheres with a range of oxygen partial pressures covering 1 x 10{sup -5} to 1 x 10{sup -15}atm. Characterization of the interfaces was performed using four techniques: scanning electron microscopy (SEM), energy dispersive X-ray (EDS), X-ray photoelectron spectroscopy (XPS), and oxygen interstitial analysis. The bulk oxygen concentrations in the copper-active metal alloys were determined by a LECO oxygen analyzer, before and after the brazing operation. Wetting of sapphire by Cu-Ti alloys was characterized as a function of time and temperature. Additionally, the work of adhesion in the Cu-Ti-O/sapphire (single crystal) system was found to better correlate with the oxygen concentration in the alloy than with the titanium content itself. The amount of titanium necessary to promote wetting was also optimized to low levels, commensurate with the oxygen content present in the copper alloy.

  8. Effects of adenosine metabolism in astrocytes on central nervous system oxygen toxicity.

    PubMed

    Chen, Yu-liang; Zhang, Ya-nan; Wang, Zhong-zhuang; Xu, Wei-gang; Li, Run-ping; Zhang, Jun-dong

    2016-03-15

    Hyperbaric oxygen (HBO) is widely used in military operations, especially underwater missions. However, prolonged and continuous inhalation of HBO can cause central nervous system oxygen toxicity (CNS-OT), which greatly limits HBO's application. The regulation of astrocytes to the metabolism of adenosine is involved in epilepsy. In our study, we aimed to observe the effects of HBO exposure on the metabolism of adenosine in the brain. Furthermore, we aimed to confirm the possible mechanism underlying adenosine's mediation of the CNS-OT. Firstly, anesthetized rats exposed to 5 atm absolute HBO for 80 min. The concentrations of extracellular adenosine, ATP, ADP, and AMP were detected. Secondly, free-moving rats were exposed to HBO at the same pressure for 20 min, and the activities of 5'-nucleotidase and ADK in brain tissues were measured. For the mechanism studies, we observed the effects of a series of different doses of drugs related to adenosine metabolism on the latency of CNS-OT. Results showed HBO exposure could increase adenosine content by inhibiting ADK activity and improving 5'-nucleotidase activity. And adenosine metabolism during HBO exposure may be a protective response against HBO-induced CNS-OT. Moreover, the improvement of adenosine concentration, activation of adenosine A1R, or suppression of ADK and adenosine A2AR, which are involved in the prevention of HBO-induced CNS-OT. This is the first study to demonstrate HBO exposure regulated adenosine metabolism in the brain. Adenosine metabolism and adenosine receptors are related to HBO-induced CNS-OT development. These results will provide new potential targets for the termination or the attenuation of CNS-OT.

  9. A new oxygen barometer for solar system basaltic glasses based on vanadium valence

    SciTech Connect

    Karner, J.M.; Sutton, S.R.; Papike, J.J.; Delaney, J.S.; Shearer, C.K.; Newville, M.; Eng, P.; Rivers, M.; Dyar, M.D.

    2004-05-10

    An oxybarometer based on vanadium valence and applicable to basaltic glasses covers eight orders of magnitude in oxygen fugacity. The determination of oxidation conditions for basaltic magmas derived by the melting of planetary mantles is critical to our understanding of the nature and evolution of planetary interiors. Yet, these determinations are compromised in terrestrial and especially extraterrestrial basalts by our analytical and computational methods for estimating oxygen fugacity (fO{sub 2}). For example, mineralogical barometers (1, 2) can be reduced in effectiveness by subsolidus re-equilibration of mineral assemblages, inversion of mineralogical data to melt characteristics, and deviations of the natural mineral compositions from ideal thermodynamic parameters. Likewise, techniques to estimate fO{sub 2} based on the valence state of Fe (i.e. Fe{sup 3+}/Fe{sup 2+}) are ineffective for materials that crystallized at or below the IW buffer, and only contain Fe{sup 2+} and Fe{sup 0} (3). For these reasons, we have developed an oxybarometer based on the valence state of vanadium in basaltic glasses. This oxybarometer has enormous potential because (1) V valence is measured in basaltic glasses that have been quenched at near liquidus temperatures, thereby recording magmatic fO{sub 2} conditions, and (2) V is a multivalent element, existing as V{sup 2+}, V{sup 3+}, V{sup 4+}, and V{sup 5+}, thus allowing for applicability over a range of redox conditions from the most reduced materials in the solar system, (e.g. calcium aluminum rich inclusions in chondritic meteorites [4]) to the most oxidized terrestrial magmas (this work).

  10. Therapeutic ketosis with ketone ester delays central nervous system oxygen toxicity seizures in rats.

    PubMed

    D'Agostino, Dominic P; Pilla, Raffaele; Held, Heather E; Landon, Carol S; Puchowicz, Michelle; Brunengraber, Henri; Ari, Csilla; Arnold, Patrick; Dean, Jay B

    2013-05-15

    Central nervous system oxygen toxicity (CNS-OT) seizures occur with little or no warning, and no effective mitigation strategy has been identified. Ketogenic diets (KD) elevate blood ketones and have successfully treated drug-resistant epilepsy. We hypothesized that a ketone ester given orally as R,S-1,3-butanediol acetoacetate diester (BD-AcAc(2)) would delay CNS-OT seizures in rats breathing hyperbaric oxygen (HBO(2)). Adult male rats (n = 60) were implanted with radiotelemetry units to measure electroencephalogram (EEG). One week postsurgery, rats were administered a single oral dose of BD-AcAc(2), 1,3-butanediol (BD), or water 30 min before being placed into a hyperbaric chamber and pressurized to 5 atmospheres absolute (ATA) O2. Latency to seizure (LS) was measured from the time maximum pressure was reached until the onset of increased EEG activity and tonic-clonic contractions. Blood was drawn at room pressure from an arterial catheter in an additional 18 animals that were administered the same compounds, and levels of glucose, pH, Po(2), Pco(2), β-hydroxybutyrate (BHB), acetoacetate (AcAc), and acetone were analyzed. BD-AcAc(2) caused a rapid (30 min) and sustained (>4 h) elevation of BHB (>3 mM) and AcAc (>3 mM), which exceeded values reported with a KD or starvation. BD-AcAc(2) increased LS by 574 ± 116% compared with control (water) and was due to the effect of AcAc and acetone but not BHB. BD produced ketosis in rats by elevating BHB (>5 mM), but AcAc and acetone remained low or undetectable. BD did not increase LS. In conclusion, acute oral administration of BD-AcAc(2) produced sustained ketosis and significantly delayed CNS-OT seizures by elevating AcAc and acetone.

  11. Analysis of nitrogenous and algal oxygen demand in effluent from a system of aerated lagoons followed by polishing pond.

    PubMed

    Khorsandi, Hassan; Alizadeh, Rahimeh; Tosinejad, Horiyeh; Porghaffar, Hadi

    2014-01-01

    In this descriptive-analytical study, nitrogenous and algal oxygen demand were assessed for effluent from a system of facultative partially mixed lagoons followed by the polishing pond using 120 grab samples over 1 year. Filtered and non-filtered samples of polishing pond effluent were tested in the presence and absence of a nitrification inhibitor. Effective factors, including 5-day biochemical and chemical oxygen demand (BOD and COD), total suspended solids (TSS), dissolved oxygen, chlorophyll A, and temperature, were measured using standard methods for water and wastewater tests. The results were analyzed using repeated measures analysis of variance with SPSS version 16. Findings show that the annual mean of the total 5-day BOD in the effluent from the polishing pond consisted of 44.92% as the algal carbonaceous biochemical oxygen demand (CBOD), 43.61% as the nitrogenous biochemical oxygen demand (NBOD), and 11.47% as the soluble CBOD. According to this study, the annual mean ratios of algal COD and 5-day algal CBOD to TSS were 0.8 and 0.37, respectively. As the results demonstrate, undertaking quality evaluation of the final effluent from the lagoons without considering nitrogenous and algal oxygen demand would undermine effluent quality assessment and interpretation of the performance of the wastewater treatment plant.

  12. 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 ...

  13. A combined photocatalytic determination system for chemical oxygen demand with a highly oxidative reagent.

    PubMed

    Zhang, Aiyong; Zhou, Minghua; Zhou, Qixing

    2011-02-07

    This study focuses on the proposal and validation of a combined photocatalytic (PC) system and a three-parameterized procedure for the determination of chemical oxygen demand (COD; PcCOD(combined)), with a highly oxidative reagent utilized as a photoelectron scavenger and signal indicator. The PcCOD(combined) was the functional combination of photon-efficient thin-layer photocatalytic oxidation, conventional bulk-phase photocatalytic oxidation and photocarrier-efficient high-activity photocatalytic reduction in one single photodigestion system, and consequently, this system possessed high photon-utilization efficiency, automatic stirring function and satisfactory determination characteristics. In comparison with the conventional one-parameterized procedure, the three-parameterized procedure introduces the blank and total photocatalytic reduction responses as two of the three significant analytical parameters. Under the optimized pH value of 3.0-4.5 and a rotating rate of 40 rpm, the representative KMnO(4) species was used for the PcCOD(combined) system as the combined high-activity oxidant, and a narrow and reliable analytical linear range of 0-260 mg L(-1) was achieved during the 10 min duration of the determinations. No observable interference of Cl(-) was found at concentration of the ion up to 2000 mg L(-1). A real sample analysis indicated that the measured values for the PcCOD(combined) were all within a relative deviation below 5% of COD(Cr) of the standard method, which further validates the practical feasibility of the proposed PcCOD(combined) system.

  14. Oxygen chemisorption cryogenic refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor)

    1987-01-01

    The present invention relates to a chemisorption compressor cryogenic refrigerator which employs oxygen to provide cooling at 60 to 100 K. The invention includes dual vessels containing an oxygen absorbent material, alternately heated and cooled to provide a continuous flow of high pressure oxygen, multiple heat exchangers for precooling the oxygen, a Joule-Thomson expansion valve system for expanding the oxygen to partially liquefy it and a liquid oxygen pressure vessel. The primary novelty is that, while it was believed that once oxygen combined with an element or compound the reaction could not reverse to release gaseous oxygen, in this case oxygen will indeed react in a reversible fashion with certain materials and will do so at temperatures and pressures which make it practical for incorporation into a cryogenic refrigeration system.

  15. Management of traumatic brain injury: nursing practice guidelines for cerebral perfusion and brain tissue oxygenation (PbtO2) systems.

    PubMed

    Hession, Diane

    2008-01-01

    Traditional modes of preventing brain cell death in traumatic brain injury (TBI) focus on the enhancement of cerebral perfusion pressure and control of intracranial pressure. Brain tissue oxygenation (PbtO2) monitoring systems are currently available to provide early detection of diminished cerebral oxygenation, and ultimately, ischemia. Research has demonstrated that early detection in PbtO2 is a more delicate measurement of cerebral blood flow and oxygenation. Monitoring PbtO2, in conjunction with cerebral perfusion pressure and intracranial pressure, has been shown to be a better guide to the prevention and treatment of secondary cerebral ischemia. This article reviews TBI, a PbtO2 monitor system description and indications for use, and the importance of nursing practice guidelines and education. With proper guidelines and education, this new technology can be used effectively by bedside clinicians and educators in adult and pediatric intensive care units.

  16. Design and Testing of the Primary and Secondary Oxygen Regulators for the Flexible Portable Life Support System (FlexPLSS)

    NASA Technical Reports Server (NTRS)

    Campbell, Colin; Hepworth, Mark

    2010-01-01

    The next generation space suit requires additional capabilities for controlling and adjusting internal pressure compared to that of historical designs. Although the general configuration of the oxygen systems for the next generation space suit is similar or derived from the Apollo and Shuttle Extravehicular Mobility Unit (EMU) with Primary closed loop life support operation and Secondary sourced open loop life support operations, nearly everything else has evolved with new available technologies. For the case of the primary and secondary regulators, the design has gone away from purely mechanical systems actuated with pull-cords or "bicycle cables" to electro-mechanical hybrids that provide the best of both worlds with respect to power draw, reliability, and versatility. This paper discusses the development and testing of a Secondary Oxygen Regulator bench-top prototype along with comparisons of operation with the various prototypes for the Primary Oxygen Regulator.

  17. Parallel Electrochemical Treatment System and Application for Identifying Acid-Stable Oxygen Evolution Electrocatalysts

    DOE PAGES

    Jones, Ryan J. R.; Shinde, Aniketa; Guevarra, Dan; ...

    2015-01-05

    There are many energy technologies require electrochemical stability or preactivation of functional materials. Due to the long experiment duration required for either electrochemical preactivation or evaluation of operational stability, parallel screening is required to enable high throughput experimentation. We found that imposing operational electrochemical conditions to a library of materials in parallel creates several opportunities for experimental artifacts. We discuss the electrochemical engineering principles and operational parameters that mitigate artifacts int he parallel electrochemical treatment system. We also demonstrate the effects of resistive losses within the planar working electrode through a combination of finite element modeling and illustrative experiments. Operationmore » of the parallel-plate, membrane-separated electrochemical treatment system is demonstrated by exposing a composition library of mixed metal oxides to oxygen evolution conditions in 1M sulfuric acid for 2h. This application is particularly important because the electrolysis and photoelectrolysis of water are promising future energy technologies inhibited by the lack of highly active, acid-stable catalysts containing only earth abundant elements.« less

  18. Parallel Electrochemical Treatment System and Application for Identifying Acid-Stable Oxygen Evolution Electrocatalysts

    SciTech Connect

    Jones, Ryan J. R.; Shinde, Aniketa; Guevarra, Dan; Xiang, Chengxiang; Haber, Joel A.; Jin, Jian; Gregoire, John M.

    2015-01-05

    There are many energy technologies require electrochemical stability or preactivation of functional materials. Due to the long experiment duration required for either electrochemical preactivation or evaluation of operational stability, parallel screening is required to enable high throughput experimentation. We found that imposing operational electrochemical conditions to a library of materials in parallel creates several opportunities for experimental artifacts. We discuss the electrochemical engineering principles and operational parameters that mitigate artifacts int he parallel electrochemical treatment system. We also demonstrate the effects of resistive losses within the planar working electrode through a combination of finite element modeling and illustrative experiments. Operation of the parallel-plate, membrane-separated electrochemical treatment system is demonstrated by exposing a composition library of mixed metal oxides to oxygen evolution conditions in 1M sulfuric acid for 2h. This application is particularly important because the electrolysis and photoelectrolysis of water are promising future energy technologies inhibited by the lack of highly active, acid-stable catalysts containing only earth abundant elements.

  19. Applying the Ce-in-zircon oxygen geobarometer to diverse silicic magmatic systems

    NASA Astrophysics Data System (ADS)

    Claiborne, L. L.; Miller, C. F.

    2012-12-01

    Zircon provides information on age, temperature, and composition of the magma from which it grew. In systems such as Mount St. Helens, where zircon is not coeval with the rest of the crystal cargo, it provides the only accessible record of the extended history of the magmatic system, including cycles of intrusion, crystallization and rejuvenation beneath an active volcano (Claiborne et al., 2010). The rare earth elements, which are present in measureable quantities in zircon, provide information about the composition of the magma from which zircon grew. Unique among the generally trivalent rare earth elements, cerium can exist as either trivalent or tetravalent, depending on the oxidation state of the magma. The tetravalent ion is highly compatible in zircon, in the site that usually hosts tetravalent zirconium, and so the amount of Cerium in zircon relative (relative to what would be expected of trivalent Ce) depends the oxidation state of the magma from which it grew. Trail et al. (2011) proposed a calibration based on experimental data that uses the Ce anomaly in zircon as a direct proxy for magma oxidation (fugacity), describing the relationship between Ce in zircon and magma oxygen fugacity as ln(Ce/Ce*)D = (0.1156±0.0050)xln(fO2)+(13860±708)/T-(6.125±0.484). For systems like Mount St. Helens, where the major minerals record only events in the hundreds to thousands of years leading to eruption, (including the Fe-Ti oxides traditionally relied upon for records of oxidation state of the magmas), this presents a novel approach for understanding more extended histories of oxidation of magmas in the tens and hundreds of thousands of years of magmatism at a volcanic center. This calibration also promises to help us better constrain conditions of crystallization in intrusive portions of volcanic systems, as well as plutonic bodes. We apply this new oxygen geobarometer to natural volcanic and plutonic zircons from a variety of tectonic settings, and compare to

  20. Atomic Oxygen Exposure of Power System and other Spacecraft Materials: Results of the EOIM-3 Experiment

    NASA Technical Reports Server (NTRS)

    Morton, Thomas L.; Ferguson, Dale C.

    1997-01-01

    In order to test their reactivity with Atomic Oxygen, twenty five materials were flown on the EOIM-3 (Evaluation of Oxygen Interactions with Materials) portion of the STS-46 Mission. These materials include refractory metals, candidate insulation materials, candidate radiator coatings, and a selection of miscellaneous materials. This report documents the results of the pre- and post-flight analysis of these materials.

  1. Electrochemical reduction of oxygen in aprotic ionic liquids containing metal cations: Na-O2 system case study.

    PubMed

    Azaceta, Eneko; Lutz, Lukas; Grimaud, Alexis; Vicent-Luna, Jose Manuel; Hamad, Said; Yate, Luis; Cabañero, Geman; Grande, Hans-Jurgen; Anta, Juan Antonio; Tarascon, Jean-Marie; Tena-Zaera, Ramon

    2017-01-19

    Metal-air batteries are intensively studied because of their high theoretical energy storage capability. However, the fundamental science at work dealing with electrodes, electrolytes and reaction products still need to be better understood. In this report, the ionic liquid N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (PYR14TFSI) is chosen to study the influence of a wide range of metal cations (Mn+) on the electrochemical behavior of oxygen.. We demonstrate the relevance of the Lewis hard-soft acid-base (HSAB) theory to predict satisfactorily the reduction potential of the oxygen reduction in electrolytes containing metal cations. Systems with soft and intermediate Mn+ acidity are shown to facilitate oxygen reduction and metal oxide formation, whereas oxygen reduction is hampered by hard acid cations such as sodium (or lithium). Furthermore, the Density Functional Theory calculations on the energy formation of the resulting metal oxides rationalizes the effect of the Mn* on the oxygen reduction. The case study of Na-O2 system is described in detail. We show that, among others, the Na+ electrolyte concentration controls the electrochemical pathway, (solution precipitation vs. surface deposition) by which discharge product growth. All in all, fundamental insights to design advanced electrolytes for metal-air batteries and Na-air ones in particular are provided.

  2. Manned Test and Evaluation of Morgan Breathing System 2000 (MBS 2000) Oxygen Monitoring System

    DTIC Science & Technology

    2010-05-01

    19. ABSTRACT: The MBS 2000 is an O2 rebreather intended for O2 decompression use in a dry chamber. Users purge the breathing loop with O2 at preset...The MBS 2000 is an O2 rebreather intended for use in a dry chamber by submariners removed from a pressurized submarine. Currently, MBS 2000 users...system (OMS) in the MBS 2000 rebreather consists of an O2 sensor that measures O2 partial pressure (PO2), not the fraction of O2 (FO2), in the inspired

  3. In-vivo monitoring of tissue oxygen saturation in deep brain structures using a single fiber optical system

    PubMed Central

    Yu, Linhui; Wu, Ying; Dunn, Jeff F.; Murari, Kartikeya

    2016-01-01

    We propose a single fiber optical system for monitoring tissue oxygen saturation (sO2) based on continuous-wave reflectance spectroscopy in the visible wavelengths. The system is designed for measurements in deep brain structures by stereotaxically implanting the 200 μm-core fiber probe into the tissue of interest. Monte Carlo (MC) simulations were used to estimate the measurement tissue volume between 0.02–0.03 mm3. Experiments in an optical phantom indicated the system had a root mean squared error (RMSE) of 4.21% compared with a commercial fluorescence-based tissue oxygen partial pressure measuring system. Finally, we used the system for continuously monitoring tissue sO2 from a highly-localized volume in anesthetized mice. PMID:27896007

  4. Molecular Photocatalytic Systems for Solar Energy Conversion: Catalysts for the Evolution of Hydrogen and Oxygen from Water

    NASA Astrophysics Data System (ADS)

    Zamaraev, Kirill I.; Parmon, Valentin N.

    1983-09-01

    This review is devoted to recent advances in the development and study of homogeneous and heterogeneous catalysts for the reduction of water to molecular hydrogen and its oxidation to molecular oxygen. The production of micro-heterogeneous systems for photocatalytic charge separation is also discussed. 114 references.

  5. Advanced fluorocarbon-based systems for oxygen and drug delivery, and diagnosis.

    PubMed

    Riess, J G; Krafft, M P

    1997-01-01

    Fluorocarbons and fluorocarbon-derived materials constitute a vast family of synthetic components that have a range of remarkable properties including exceptional chemical and biological inertness, gas-dissolving capacity, low surface tension, high fluidity, excellent spreading characteristics, unique hydro- and lipophobicity, high density, absence of protons, and magnetic susceptibility close to that of water. These properties lead to a diversity of products and applications as illustrated by those products that are already in advanced clinical trials, which comprise: 1) an injectable oxygen carrier, i.e. blood substitute, consisting of a fluorocarbon-in-water emulsion for use in surgery to alleviate the problems raised by the transfusion of homologous blood; the same emulsion is also being evaluated with cardiopulmonary bypass patients; 2) a neat fluorocarbon for treatment of acute respiratory failure by liquid ventilation; and 3) fluorocarbon-based or stabilized gas bubbles to be used as contrast agents for the assessment of heart function and detection of perfusion defects by ultrasound imaging. Proper selection of the fluorocarbon best suited for the intended application, formulation optimization, and advanced stabilization and processing procedures led to effective, ready-for-use products with minimal side-effects. Further highly fluorinated materials, including amphiphiles and various fluorocarbon-based colloidal systems that have potential as pulmonary, topical and ophthalmological drug delivery agents, and as skin protection barriers, are now being investigated. Such systems include drug-in-fluorocarbon suspensions, reverse water-in-fluorocarbon emulsions, oil-in-fluorocarbon emulsions, multiple emulsions, microemulsions, fluorocarbon gels, fluorinated liposomes, fluorinated tubules and other novel supramolecular systems.

  6. Refractory vasculitic ulcer of the toe in adolescent suffering from Systemic Lupus Erythematosus treated successfully with hyperbaric oxygen therapy

    PubMed Central

    2010-01-01

    Skin ulcers are a dangerous and uncommon complication of vasculitis. We describe the case of a teenager suffering from Systemic Lupus Erythematosus with digital ulcer resistant to conventional therapy, treated successfully with Hyperbaric Oxygen Therapy. The application of hyperbaric oxygen, which is used for the treatment of ischemic ulcers, is an effective and safe therapeutic option in patients with ischemic vasculitic ulcers in combination with immunosuppressive drugs. Further studies are needed to evaluate its role as primary therapy for this group of patients. PMID:21040521

  7. The development of a non-cryogenic nitrogen/oxygen supply system. [using hydrazine/water electrolysis

    NASA Technical Reports Server (NTRS)

    Greenough, B. M.; Mahan, R. E.

    1974-01-01

    A hydrazine/water electrolysis process system module design was fabricated and tested to demonstrate component and module performance. This module is capable of providing both the metabolic oxygen for crew needs and the oxygen and nitrogen for spacecraft leak makeup. The component designs evolved through previous R and D efforts, and were fabricated and tested individually and then were assembled into a complete module which was successfully tested for 1000 hours to demonstrate integration of the individual components. A survey was made of hydrazine sensor technology and a cell math model was derived.

  8. System for the measurement of blood flow and oxygenation in tissue applied to neurovascular coupling in brain

    NASA Astrophysics Data System (ADS)

    Kohl-Bareis, Matthias; Leithner, Christoph; Sellien, Heike; Guertler, Roland; Geraskin, Dmitri; Rohrer, Benjamin; Royl, Georg; Dirnagl, Ulrich; Lindauer, Ute

    2005-08-01

    We designed a system incorporating the independent measurement of blood flow and oxygenation of haemoglobin. This is based on laser-Doppler spectroscopy with NIR wavelengths which gives a measure for changes in blood flow or tissue perfusion as well as reflectance spectroscopy in the VIS wavelength range for the calculation of the oxygenated and deoxygenated haemoglobin components. The co-registration of these parameters allows the neurovascular coupling of brain to be investigated. This is demonstrated by recording functional activity of the rat brain during electrical forepaw stimulation.

  9. Iron- and ferritin-dependent reactive oxygen species distribution: impact on Arabidopsis root system architecture.

    PubMed

    Reyt, Guilhem; Boudouf, Soukaina; Boucherez, Jossia; Gaymard, Frédéric; Briat, Jean-Francois

    2015-03-01

    Iron (Fe) homeostasis is integrated with the production of reactive oxygen species (ROS), and distribution at the root tip participates in the control of root growth. Excess Fe increases ferritin abundance, enabling the storage of Fe, which contributes to protection of plants against Fe-induced oxidative stress. AtFer1 and AtFer3 are the two ferritin genes expressed in the meristematic zone, pericycle and endodermis of the Arabidopsis thaliana root, and it is in these regions that we observe Fe stained dots. This staining disappears in the triple fer1-3-4 ferritin mutant. Fe excess decreases primary root length in the same way in wild-type and in fer1-3-4 mutant. In contrast, the Fe-mediated decrease of lateral root (LR) length and density is enhanced in fer1-3-4 plants due to a defect in LR emergence. We observe that this interaction between excess Fe, ferritin, and root system architecture (RSA) is in part mediated by the H2O2/O2·- balance between the root cell proliferation and differentiation zones regulated by the UPB1 transcription factor. Meristem size is also decreased in response to Fe excess in ferritin mutant plants, implicating cell cycle arrest mediated by the ROS-activated SMR5/SMR7 cyclin-dependent kinase inhibitors pathway in the interaction between Fe and RSA.

  10. Climatically-Active Gases in the Eastern Boundary Upwelling and Oxygen Minimum Zone (OMZ) Systems

    NASA Astrophysics Data System (ADS)

    Garbe, C.; Garçon, V.; Butz, A.; Yahia, H.; Sudre, J.; Illig, S.; Dewitte, B.; Paulmier, A.; Dadou, I.

    2012-04-01

    The EBUS (Eastern Boundary Upwelling Systems) and OMZs (Oxygen Minimum Zone) contribute very significantly to the gas exchange between the ocean and the atmosphere, notably with respect to the greenhouse gases (hereafter GHG). From in-situ ocean measurements, the uncertainty of the net global ocean-atmosphere CO2 fluxes is between 20 and 30%, and could be much higher in the EBUS-OMZ. Off Peru, very few in-situ data are available presently, which justifies alternative approaches for assessing these fluxes. GHG air-sea fluxes determination can be inferred from inverse modeling applied to Vertical Column Densities (VCDs) from GOSAT, using state of the art modeling, at low spatial resolution. For accurately linking sources of GHGs to EBUS and OMZs, the resolution of the source regions needs to be increased. This task develops on new non-linear and multiscale processing methods for complex signals to infer a higher spatial resolution mapping of the fluxes and the associated sinks and sources between the atmosphere and the ocean. The use of coupled satellite data (e.g. SST and/or Ocean colour) that carry turbulence information associated to ocean dynamics is taken into account at unprecedented detail level to incorporate turbulence effects in the evaluation of the air-sea fluxes. We will present a framework as described above for determining sources and sinks of GHG from satellite remote sensing with the Peru OMZ as a test bed.

  11. High-temperature phase relations and thermodynamics in the iron-titanium-oxygen system

    SciTech Connect

    Pesl, J.; Eric, R.H.

    1999-08-01

    Phase equilibria and thermodynamics in the FeO-TiO{sub 2}-Ti{sub 2}O{sub 3} ternary system were studied at 1,500 C and 1,600 C. In particular, the liquid slag-phase region and its saturation boundary with respect to metallic iron, titania, and lower titanium oxides was investigated. The liquid slag-phase region extends substantially toward an anosovite (Ti{sub 3}O{sub 5}) composition, and considerable concentrations of divalent iron coexist with trivalent titanium in the liquid-slag phase. This seems to be a consequence of the complete solid solution between ferrous pseudobrookite (FeTi{sub 2}O{sub 5}) and anosovite (Ti{sub 3}O{sub 5}), which exists at subsolidus temperatures. The liquid-slag field is significantly enlarged toward the anosovite composition upon increasing the temperature from 1,500 to 1,600 C. Activities of the components FeO and TiO{sub 2} in the liquid-slag region were determined by Gibbs-Duhem integration of the measured oxygen partial pressures at 1,500 C. The FeO shows moderate negative deviation, while titania shows a slight negative deviation in FeO-rich slags and a positive deviation in high-titania slags. The experimentally measured activity values were modeled using regular and biregular solution models, and good agreement was obtained with the biregular solution model.

  12. Enhanced single-particle brightness and photostability of semiconductor polymer dots by enzymatic oxygen scavenging system

    NASA Astrophysics Data System (ADS)

    Liu, Zhihe; Yang, Yingkun; Sun, Zezhou; Wu, Changfeng

    2016-12-01

    Semiconductor polymer dots (Pdots) are emerging as an excellent fluorescent probe in biology and medicine. However, the photostability of Pdots can't meet the requirements of long term single-particle imaging and tracking applications. Here we describe the enhanced single-particle brightness and photostability of Pdots by using an efficient enzymatic oxygen scavenging system (OSS). Pdots with particle diameters of 21 nm and 43 nm (PFBT21 and PFBT43) were prepared by a nanoprecipitation method. Single-particle imaging and photobleaching were performed to investigate the effect of OSS on the per-particle brightness and photostability of Pdots. Our results indicate that the single-particle brightness of the PFBT21 Pdots in OSS was enhanced nearly two times as compare to the PFBT21 Pdots in water. The photobleaching percentages of PFBT21 and PFBT43 in OSS were determined to be 29% and 33%, respectively. These values are decreased by 2-3 times as compared to those of the same Pdots in water, indicating the significantly improved photostability of Pdots by OSS. This study provides a promising approach for enhancing photostability of Pdots in long term single-particle tracking.

  13. Cardiovascular System Response to Carbon Dioxide and Exercise in Oxygen-Enriched Environment at 3800 m

    PubMed Central

    Liu, Guohui; Liu, Xiaopeng; Qin, Zhifeng; Gu, Zhao; Wang, Guiyou; Shi, Weiru; Wen, Dongqing; Yu, Lihua; Luo, Yongchang; Xiao, Huajun

    2015-01-01

    Background: This study explores the responses of the cardiovascular system as humans exercise in an oxygen-enriched room at high altitude under various concentrations of CO2. Methods: The study utilized a hypobaric chamber set to the following specifications: 3800 m altitude with 25% O2 and different CO2 concentrations of 0.5% (C1), 3.0% (C2) and 5.0% (C3). Subjects exercised for 3 min three times, separated by 30 min resting periods in the above-mentioned conditions, at sea level (SL) and at 3800 m altitude (HA). The changes of heart rate variability, heart rate and blood pressure were analyzed. Results: Total power (TP) and high frequency power (HF) decreased notably during post-exercise at HA. HF increased prominently earlier the post-exercise period at 3800 m altitude with 25% O2 and 5.0% CO2 (C3), while low frequency power (LF) changed barely in all tests. The ratios of LF/HF were significantly higher during post-exercise in HA, and lower after high intensity exercise in C3. Heart rate and systolic blood pressure increased significantly in HA and C3. Conclusions: Parasympathetic activity dominated in cardiac autonomic modulation, and heart rate and blood pressure increased significantly after high intensity exercise in C3. PMID:26393634

  14. Oxygen sensing glucose biosensors based on alginate nano-micro systems

    NASA Astrophysics Data System (ADS)

    Chaudhari, Rashmi; Joshi, Abhijeet; Srivastava, Rohit

    2014-04-01

    Clinically glucose monitoring in diabetes management is done by point-measurement. However, an accurate, continuous glucose monitoring, and minimally invasive method is desirable. The research aims at developing fluorescence-mediated glucose detecting biosensors based on near-infrared radiation (NIR) oxygen sensitive dyes. Biosensors based on Glucose oxidase (GOx)-Rudpp loaded alginate microspheres (GRAM) and GOx-Platinum-octaethylporphyrin (PtOEP)-PLAalginate microsphere system (GPAM) were developed using air-driven atomization and characterized using optical microscopy, CLSM, fluorescence spectro-photometry etc. Biosensing studies were performed by exposing standard solutions of glucose. Uniform sized GRAM and GPAM with size 50+/-10μm were formed using atomization. CLSM imaging of biosensors suggests that Rudpp and PtOEP nanoparticles are uniformly distributed in alginate microspheres. The GRAM and GPAM showed a good regression constant of 0.974 and of 0.9648 over a range of 0-10 mM of glucose with a high sensitivity of 3.349%/mM (625 nm) and 2.38%/mM (645 nm) at 10 mM of glucose for GRAM and GPAM biosensor. GRAM and GPAM biosensors show great potential in development of an accurate and minimally invasive glucose biosensor. NIR dye based assays can aid sensitive, minimally-invasive and interference-free detection of glucose in diabetic patients.

  15. Thermodynamic assessment of the oxygen rich U-Ce-O system

    NASA Astrophysics Data System (ADS)

    McMurray, J. W.; Hirooka, S.; Murakami, T.; Suzuki, K.; White, J. T.; Voit, S. L.; Nelson, A. T.; Slone, B. W.; Besmann, T. M.; McClellan, K. J.; Kato, M.

    2015-12-01

    A thermodynamic assessment of the U-Ce-O system was performed by combining the existing Calphad assessments of the U-O and Ce-O binaries. A compound energy formalism representation for the fluorite U1-yCeyO2±x and a partially ionic two-sublattice liquid model for U-Ce-O melt were developed to describe the ternary solutions. Oxygen potentials for U1-yCeyO2±x for 0.05, 0.20, 0.30, and 0.50 Ce metal fractions were measured from thermogravimetric analysis and used, along with other thermodynamic data reported in the literature, to optimize the adjustable parameters of the models for U1-yCeyO2±x and the U-Ce-O ternary liquid. In addition, the thermochemical behavior of U1-yCeyO2±x and U1-yPuyO2±x was compared in order to assess the suitability of using Ce as a surrogate for Pu in MOX fuel.

  16. A specific c-type cytochrome maturation system is required for oxygenic photosynthesis

    PubMed Central

    Kuras, Richard; Saint-Marcoux, Denis; Wollman, Francis-André; de Vitry, Catherine

    2007-01-01

    Oxygenic photosynthesis is an important bioenergetic process that maintains the Earth's atmosphere and allows carbon fixation. A critical enzyme in this process, the cytochrome b6f complex, differs from other protein complexes of the same family by an unusual covalently attached cofactor chemically defined as a c′ heme. We have identified a set of pioneer proteins that carry the biogenesis of this c′ heme and started their characterization. They are encoded by the genomes of all organisms performing oxygenic photosynthesis, whatever their phylogenetic distances. These proteins are thus among the few that distinguish photosynthetic cells evolving oxygen from other types of living cells. PMID:17535914

  17. A specific c-type cytochrome maturation system is required for oxygenic photosynthesis.

    PubMed

    Kuras, Richard; Saint-Marcoux, Denis; Wollman, Francis-André; de Vitry, Catherine

    2007-06-05

    Oxygenic photosynthesis is an important bioenergetic process that maintains the Earth's atmosphere and allows carbon fixation. A critical enzyme in this process, the cytochrome b(6)f complex, differs from other protein complexes of the same family by an unusual covalently attached cofactor chemically defined as a c' heme. We have identified a set of pioneer proteins that carry the biogenesis of this c' heme and started their characterization. They are encoded by the genomes of all organisms performing oxygenic photosynthesis, whatever their phylogenetic distances. These proteins are thus among the few that distinguish photosynthetic cells evolving oxygen from other types of living cells.

  18. Allocation of supplementary aeration stations in the Chicago waterway system for dissolved oxygen improvement.

    PubMed

    Alp, Emre; Melching, Charles S

    2011-06-01

    The Chicago Waterway System (CWS), used mainly for commercial and recreational navigation and for urban drainage, is a 122.8 km branching network of navigable waterways controlled by hydraulic structures. The CWS receives pollutant loads from 3 of the largest wastewater treatment plants in the world, nearly 240 gravity Combined Sewer Overflows (CSO), 3 CSO pumping stations, direct diversions from Lake Michigan, and eleven tributary streams or drainage areas. Even though treatment plant effluent concentrations meet the applicable standards and most reaches of the CWS meet the applicable water quality standards, Dissolved Oxygen (DO) standards are not met in the CWS during some periods. A Use Attainability Analysis was initiated to evaluate what water quality standards can be achieved in the CWS. The UAA team identified several DO improvement alternatives including new supplementary aeration stations. Because of the dynamic nature of the CWS, the DUFLOW model that is capable of simulating hydraulics and water quality processes under unsteady-flow conditions was used to evaluate the effectiveness of new supplementary aeration stations. This paper details the use of the DUFLOW model to size and locate supplementary aeration stations. In order to determine the size and location of supplemental aeration stations, 90% compliance with a 5 mg/l DO standard was used as a planning target. The simulations showed that a total of four new supplementary aeration stations with oxygen supply capacities ranging from 30 to 80 g/s would be sufficient to meet the proposed target DO concentration for the North Branch and South Branch of the Chicago River. There are several aeration technologies, two of which are already being used in the CWS, available and the UAA team determined that the total capital costs of the alternatives range from $35.5 to $89.9 million with annual operations and maintenance costs ranging from $554,000 to $2.14 million. Supplemental aeration stations have been

  19. Shock tube measurements of growth constants in the branched chain formaldehyde-carbon monoxide-oxygen system

    NASA Technical Reports Server (NTRS)

    Brabbs, T. A.; Brokaw, R. S.

    1982-01-01

    Exponential free radical growth constants were measured for formaldehyde carbon monoxide-oxygen systems by monitoring the growth of oxygen atom concentration as manifested by CO flame band emission. Data were obtained over the temperature range of 1200 to 2000 K. The data were analyzed using a formaldehyde oxidation mechanism involving 12 elementary reaction steps. The computed growth constants are roughly in accord with experimental values, but are much more temperature dependent. The data was also analyzed assuming formaldehyde is rapidly decomposed to carbon monoxide and hydrogen. Growth constants computed for the resulting carbon monoxide hydrogen oxygen mixtures have a temperature dependence similar to experiments; however, for most mixtures, the computed growth constants were larger than experimental values.

  20. Probing Saltern Brines with an Oxygen Electrode: What Can We Learn about the Community Metabolism in Hypersaline Systems?

    PubMed Central

    Oren, Aharon

    2016-01-01

    We have explored the use of optical oxygen electrodes to study oxygenic photosynthesis and heterotrophic activities in crystallizer brines of the salterns in Eilat, Israel. Monitoring oxygen uptake rates in the dark enables the identification of organic substrates that are preferentially used by the community. Addition of glycerol (the osmotic solute synthesized by Dunaliella) or dihydroxyacetone (produced from glycerol by Salinibacter) enhanced respiration rates. Pyruvate, produced from glycerol or from some sugars by certain halophilic Archaea also stimulated community respiration. Fumarate had a sparing effect on respiration, possibly as many halophilic Archaea can use fumarate as a terminal electron acceptor in respiration. Calculating the photosynthetic activity of Dunaliella by monitoring oxygen concentration changes during light/dark incubations is not straightforward as light also affects respiration of some halophilic Archaea and Bacteria due to action of light-driven proton pumps. When illuminated, community respiration of brine samples in which oxygenic photosynthesis was inhibited by DCMU decreased by ~40%. This effect was interpreted as the result of competition between two energy yielding systems: the bacteriorhodopsin proton pump and the respiratory chain of the prokaryotes. These findings have important implications for the interpretation of other published data on photosynthetic and respiratory activities in hypersaline environments. PMID:27338478

  1. Oxygen Limited Bioreactors System For Nitrogen Removal Using Immobilized Mix Culture

    NASA Astrophysics Data System (ADS)

    Pathak, B. K.; Sumino, T.; Saiki, Y.; Kazama, F.

    2005-12-01

    Recently nutrients concentrations especially nitrogen in natural water is alarming in the world wide. Most of the effort is being done on the removal of high concentration of nitrogen especially from the wastewater treatment plants. The removal efficiency is targeted in all considering the effluent discharge standard set by the national environment agency. In many cases, it does not meet the required standard and receiving water is being polluted. Eutrophication in natural water bodies has been reported even if the nitrogen concentration is low and self purification of natural systems itself is not sufficient to remove the nitrogen due to complex phenomenon. In order to recover the pristine water environment, it is very essential to explore bioreactor systems for natural water systems using immobilized mix culture. Microorganism were entrapped in Polyethylene glycol (PEG) prepolymer gel and cut into 3mm cubic immobilized pellets. Four laboratory scale micro bio-reactors having 0.1 L volumes were packed with immobilized pellets with 50% compact ratio. RUN1, RUN2, RUN3 and RUN4 were packed with immobilized pellets from reservoirs sediments, activated sludge (AS), mixed of AS, AG and biodegradable plastic and anaerobic granules (AG) respectively. Water from Shiokawa Reservoirs was feed to all reactors with supplemental ammonia and nitrite nitrogen as specified in the results and discussions. The reactors were operated dark incubated room in continuous flow mode with hydraulic retention time of 12 hours under oxygen limiting condition. Ammonium, nitrate nitrite nitrogen and total organic carbon (TOC) concentrations were measured as described in APWA and AWWA (1998). Laboratory scale four bioreactors containing different combination of immobilized cell were monitored for 218 days. Influent NH4+-N and NO2--N concentration were 2.27±0.43 and 2.05±0.41 mg/l respectively. Average dissolved oxygen concentration and pH in the reactors were 0.40-2.5 mg/l and pH 6

  2. Controlled experimental aquarium system for multi-stressor investigation: carbonate chemistry, oxygen saturation, and temperature

    NASA Astrophysics Data System (ADS)

    Bockmon, E. E.; Frieder, C. A.; Navarro, M. O.; White-Kershek, L. A.; Dickson, A. G.

    2013-02-01

    As the field of ocean acidification has grown, researchers have increasingly turned to laboratory experiments to understand the impacts of increased CO2 on marine organisms. However, other changes such as ocean warming and deoxygenation are occurring concurrently with the increasing CO2 concentrations, complicating the anthropogenic impact on organisms. This experimental aquarium design allows for independent regulation of CO2 concentration, O2 levels, and temperature in a controlled environment to study the impacts of multiple stressors. The system has the flexibility for a wide range of treatment chemistry, seawater volumes, and study organisms. Control of the seawater chemistry is achieved by equilibration of a chosen gas mixture with seawater using a Liqui-Cel® membrane contactor. Included as examples, two experiments performed using the system have shown control of CO2 between approximately 500-1400 μatm and O2 from 80-240 μmol kg-1. Temperature has been maintained to 0.5 °C or better in the range of 10-17 °C. On a weeklong timescale, control results in variability in pH of less than 0.007 pH units and in oxygen concentration less than 3.5 μmol kg-1. Longer experiments, over a month, have been completed with reasonable but lessened control, still better than 0.08 pH units and 13 μmol kg-1 O2. The ability to study the impacts of multiple stressors in the laboratory simultaneously, as well as independently, will be an important part of understanding the response of marine organisms to a high-CO2 world.

  3. Iron release from corroded iron pipes in drinking water distribution systems: effect of dissolved oxygen.

    PubMed

    Sarin, P; Snoeyink, V L; Bebee, J; Jim, K K; Beckett, M A; Kriven, W M; Clement, J A

    2004-03-01

    Iron release from corroded iron pipes is the principal cause of "colored water" problems in drinking water distribution systems. The corrosion scales present in corroded iron pipes restrict the flow of water, and can also deteriorate the water quality. This research was focused on understanding the effect of dissolved oxygen (DO), a key water quality parameter, on iron release from the old corroded iron pipes. Corrosion scales from 70-year-old galvanized iron pipe were characterized as porous deposits of Fe(III) phases (goethite (alpha-FeOOH), magnetite (Fe(3)O(4)), and maghemite (alpha-Fe(2)O(3))) with a shell-like, dense layer near the top of the scales. High concentrations of readily soluble Fe(II) content was present inside the scales. Iron release from these corroded pipes was investigated for both flow and stagnant water conditions. Our studies confirmed that iron was released to bulk water primarily in the ferrous form. When DO was present in water, higher amounts of iron release was observed during stagnation in comparison to flowing water conditions. Additionally, it was found that increasing the DO concentration in water during stagnation reduced the amount of iron release. Our studies substantiate that increasing the concentration of oxidants in water and maintaining flowing conditions can reduce the amount of iron release from corroded iron pipes. Based on our studies, it is proposed that iron is released from corroded iron pipes by dissolution of corrosion scales, and that the microstructure and composition of corrosion scales are important parameters that can influence the amount of iron released from such systems.

  4. A centrifugal pump driven tidal flow extracorporeal membrane oxygenation system tested with neonatal mock circulation.

    PubMed

    Trittenwein, G; Kölbl, R; Trittenwein, H; Golej, J; Burda, G; Hermon, M; Pollak, A

    1999-06-01

    In 1993, Chevalier published his experiences with tidal flow venovenous extracorporeal membrane oxygenation (ECMO) featuring a single lumen cannula, non-occlusive roller pump, and alternating clamps. Using a neonatal mock circulation (NMC), which enables different hemodynamic states for neonatal ECMO research, the tested hypothesis was that it is possible to create a centrifugal pump driven tidal flow neonatal venovenous ECMO system. Additionally, the resulting hemodynamic effects in a condition of circulatory impairment were investigated. The ECMO circuit tested was assembled using a pediatric centrifugal pump head, a distensible reservoir, and a rotary clamp separating drainage from the injection phase. Using the NMC, end tidal volumes, mock circulation flow, and arterial and venous pressures were measured at different pump speeds after the drainage and injection phases. Effective venovenous ECMO flow (evvEF) was calculated. Mock circulation baseline values (ECMO clamped) were compared to values during tidal flow ECMO. At 3,000 rpm, a centrifugal pump speed of 75 ml/kg/min evvEF was reached, and it increased with higher pump speeds. At this point, the end tidal mock circulation flow (representing cardiac output) after drainage differed significantly from that during the injection phase (p < 0.01) but not from the baseline value. The end tidal arterial and venous pressures after the drainage phase were found to be significantly decreased compared to the baselines (p < 0.01). In conclusion, a centrifugal pump driven tidal flow venovenous ECMO system can be created enabling sufficient tidal volumes. Tested in the described NMC simulating posthypoxic circulatory impairment, significant hemodynamic effects could be demonstrated. Animal experiments for confirmation are necessary.

  5. CONTINUOUS, AUTOMATED AND SIMULTANEOUS MEASUREMENT OF OXYGEN UPTAKE AND CARBON DIOXIDE EVOLUTION IN BIOLOGICAL SYSTEMS

    EPA Science Inventory

    Commercial respirometers are capable of continuously and automatically measuring oxygen uptake in bioreactors. A method for continuously and automatically measuring carbon dioxide evolution can be retrofitted to commercial respirometers. Continuous and automatic measurements of...

  6. 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.

  7. Investigation of oxygen vacancies in CeO2/Pt system with synchrotron light techniques

    NASA Astrophysics Data System (ADS)

    Braglia, L.; Bugaev, A. L.; Lomachenko, K. A.; Soldatov, A. V.; Lamberti, C.; Guda, A. A.

    2016-05-01

    A peculiar property of ceria is the ease to form oxygen vacancies, producing reactive sites or facilitating ionic diffusion. For these reasons ceria promotes catalytic activities for a number of important reactions when it is used as a support for transition metals. In our work we study the temporal evolution of oxygen vacancies formation by time-resolved XANES at Ce K- edge and XRD measurements on CeO2/Pt nanoparticles, successfully monitoring the reaction of CO oxidation.

  8. Enzyme-based online monitoring and measurement of antioxidant activity using an optical oxygen sensor coupled to an HPLC system.

    PubMed

    Quaranta, Michela; Nugroho Prasetyo, Endry; Koren, Klaus; Nyanhongo, Gibson S; Murkovic, Michael; Klimant, Ingo; Guebitz, Georg M

    2013-03-01

    It is estimated that up to 50% of the adult population take antioxidant products on a daily basis to promote their health status. Strangely, despite the well-recognized importance of antioxidants, currently there is no international standard index for labeling owing to the lack of standardized methods for antioxidant measurement in complex products. Here, an online high-performance liquid chromatography (HPLC)-based method to detect and measure the total antioxidant capacity of antioxidant samples is presented. In this approach, complex samples containing antioxidants are separated by the HPLC system, which is further coupled to an antioxidant measuring system consisting of an optical oxygen sensor, laccase, and tetramethoxy azobismethylene quinone (TMAMQ). The antioxidants, separated via HPLC, reduce TMAMQ to syringaldazine, which is then reoxidized by laccase while simultaneously consuming O(2). The amount of consumed oxygen is directly proportional to the concentration of antioxidants and is measured by the optical oxygen sensor. The sensor is fabricated by coating a glass capillary with an oxygen-sensitive thin layer made of platinum(II) meso-tetra(4-fluorophenyl)tetrabenzoporphyrin and polystyrene, which makes real-time analysis possible (t(90) = 1.1 s in solution). Four selected antioxidants (3 mM), namely, catechin, ferulic acid, naringenin (used as a control), and Trolox, representing flavonol, hydrocinnamic acid, flavanone, and vitamin E, respectively, were injected into the online antioxidant monitoring system, separated, and then mixed with the TMAMQ/laccase solution, which resulted in oxygen consumption. This study shows that, with the use of such a system, the antioxidant activity of individual antioxidant molecules in a sample and their contribution to the total antioxidant activity of the sample can be correctly assigned.

  9. Novel Wireless Sensor System for Monitoring Oxygen, Temperature and Respiration Rate of Horticultural Crops Post Harvest

    PubMed Central

    Løkke, Mette Marie; Seefeldt, Helene Fast; Edwards, Gareth; Green, Ole

    2011-01-01

    In order to design optimal packages, it is of pivotal importance to determine the rate at which harvested fresh fruits and vegetables consume oxygen. The respiration rate of oxygen (RRO2) is determined by measuring the consumed oxygen per hour per kg plant material, and the rate is highly influenced by temperature and gas composition. Traditionally, RRO2 has been determined at discrete time intervals. In this study, wireless sensor networks (WSNs) were used to determine RRO2 continuously in plant material (fresh cut broccoli florets) at 5 °C, 10 °C and 20 °C and at modified gas compositions (decreasing oxygen and increasing carbon dioxide levels). Furthermore, the WSN enabled concomitant determination of oxygen and temperature in the very close vicinity of the plant material. This information proved a very close relationship between changes in temperature and respiration rate. The applied WSNs were unable to determine oxygen levels lower than 5% and carbon dioxide was not determined. Despite these drawbacks in relation to respiration analysis, the WSNs offer a new possibility to do continuous measurement of RRO2 in post harvest research, thereby investigating the close relation between temperature and RRO2. The conclusions are that WSNs have the potential to be used as a monitor of RRO2 of plant material after harvest, during storage and packaging, thereby leading to optimized consumer products. PMID:22164085

  10. Systems analysis of transcription factor activities in environments with stable and dynamic oxygen concentrations.

    PubMed

    Rolfe, Matthew D; Ocone, Andrea; Stapleton, Melanie R; Hall, Simon; Trotter, Eleanor W; Poole, Robert K; Sanguinetti, Guido; Green, Jeffrey

    2012-07-01

    Understanding gene regulation requires knowledge of changes in transcription factor (TF) activities. Simultaneous direct measurement of numerous TF activities is currently impossible. Nevertheless, statistical approaches to infer TF activities have yielded non-trivial and verifiable predictions for individual TFs. Here, global statistical modelling identifies changes in TF activities from transcript profiles of Escherichia coli growing in stable (fixed oxygen availabilities) and dynamic (changing oxygen availability) environments. A core oxygen-responsive TF network, supplemented by additional TFs acting under specific conditions, was identified. The activities of the cytoplasmic oxygen-responsive TF, FNR, and the membrane-bound terminal oxidases implied that, even on the scale of the bacterial cell, spatial effects significantly influence oxygen-sensing. Several transcripts exhibited asymmetrical patterns of abundance in aerobic to anaerobic and anaerobic to aerobic transitions. One of these transcripts, ndh, encodes a major component of the aerobic respiratory chain and is regulated by oxygen-responsive TFs ArcA and FNR. Kinetic modelling indicated that ArcA and FNR behaviour could not explain the ndh transcript profile, leading to the identification of another TF, PdhR, as the source of the asymmetry. Thus, this approach illustrates how systematic examination of regulatory responses in stable and dynamic environments yields new mechanistic insights into adaptive processes.

  11. Oxygen control with microfluidics.

    PubMed

    Brennan, Martin D; Rexius-Hall, Megan L; Elgass, Laura Jane; Eddington, David T

    2014-11-21

    Cellular function and behavior are affected by the partial pressure of O2, or oxygen tension, in the microenvironment. The level of oxygenation is important, as it is a balance of oxygen availability and oxygen consumption that is necessary to maintain normoxia. Changes in oxygen tension, from above physiological oxygen tension (hyperoxia) to below physiological levels (hypoxia) or even complete absence of oxygen (anoxia), trigger potent biological responses. For instance, hypoxia has been shown to support the maintenance and promote proliferation of regenerative stem and progenitor cells. Paradoxically, hypoxia also contributes to the development of pathological conditions including systemic inflammatory response, tumorigenesis, and cardiovascular disease, such as ischemic heart disease and pulmonary hypertension. Current methods to study cellular behavior in low levels of oxygen tension include hypoxia workstations and hypoxia chambers. These culture systems do not provide oxygen gradients that are found in vivo or precise control at the microscale. Microfluidic platforms have been developed to overcome the inherent limits of these current methods, including lack of spatial control, slow equilibration, and unachievable or difficult coupling to live-cell microscopy. The various applications made possible by microfluidic systems are the topic of this review. In order to understand how the microscale can be leveraged for oxygen control of cells and tissues within microfluidic systems, some background understanding of diffusion, solubility, and transport at the microscale will be presented in addition to a discussion on the methods for measuring the oxygen tension in microfluidic channels. Finally the various methods for oxygen control within microfluidic platforms will be discussed including devices that rely on diffusion from liquid or gas, utilizing on-or-off-chip mixers, leveraging cellular oxygen uptake to deplete the oxygen, relying on chemical reactions in

  12. Oxygen evolution reaction catalysis

    DOEpatents

    Haber, Joel A.; Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Jones, Ryan J.; Guevarra, Dan W.; Shinde, Aniketa A.

    2016-09-06

    An Oxygen Evolution Reaction (OER) catalyst includes a metal oxide that includes oxygen, cerium, and one or more second metals. In some instances, the cerium is 10 to 80 molar % of the metals in the metal oxide and/or the catalyst includes two or more second metals. The OER catalyst can be included in or on an electrode. The electrode can be arranged in an oxygen evolution system such that the Oxygen Evolution Reaction occurs at the electrode.

  13. Replacement of Hydrochlorofluorocarbon (HCFC) -225 Solvent for Cleaning and Verification Sampling of NASA Propulsion Oxygen Systems Hardware, Ground Support Equipment, and Associated Test Systems

    NASA Technical Reports Server (NTRS)

    Mitchell, Mark A.; Lowrey, Nikki M.

    2015-01-01

    Since the 1990's, when the Class I Ozone Depleting Substance (ODS) chlorofluorocarbon-113 (CFC-113) was banned, NASA's rocket propulsion test facilities at Marshall Space Flight Center (MSFC) and Stennis Space Center (SSC) have relied upon hydrochlorofluorocarbon-225 (HCFC-225) to safely clean and verify the cleanliness of large scale propulsion oxygen systems. Effective January 1, 2015, the production, import, export, and new use of HCFC-225, a Class II ODS, was prohibited by the Clean Air Act. In 2012 through 2014, leveraging resources from both the NASA Rocket Propulsion Test Program and the Defense Logistics Agency - Aviation Hazardous Minimization and Green Products Branch, test labs at MSFC, SSC, and Johnson Space Center's White Sands Test Facility (WSTF) collaborated to seek out, test, and qualify a replacement for HCFC-225 that is both an effective cleaner and safe for use with oxygen systems. Candidate solvents were selected and a test plan was developed following the guidelines of ASTM G127, Standard Guide for the Selection of Cleaning Agents for Oxygen Systems. Solvents were evaluated for materials compatibility, oxygen compatibility, cleaning effectiveness, and suitability for use in cleanliness verification and field cleaning operations. Two solvents were determined to be acceptable for cleaning oxygen systems and one was chosen for implementation at NASA's rocket propulsion test facilities. The test program and results are summarized. This project also demonstrated the benefits of cross-agency collaboration in a time of limited resources.

  14. Dynamics of oxygen depletion in the nearshore of a coastal embayment of the southern Benguela upwelling system

    NASA Astrophysics Data System (ADS)

    Pitcher, Grant C.; Probyn, Trevor A.; du Randt, Andre; Lucas, Andrew. J.; Bernard, Stewart; Evers-King, Haley; Lamont, Tarron; Hutchings, Larry

    2014-04-01

    Acquisition of high resolution time series of water column and bottom dissolved oxygen (DO) concentrations inform the dynamics of oxygen depletion in St Helena Bay in the southern Benguela upwelling system at several scales of variability. The bay is characterized by seasonally recurrent hypoxia (<1.42 ml l-1) associated with a deep pool of oxygen-depleted water and episodic anoxia (<0.02 ml l-1) driven by the nearshore (<20 m isobath) decay of red tide. Coastal wind forcing influences DO concentrations in the nearshore through its influence on bay productivity and the development of red tides; through shoreward advection of the bottom pool of oxygen-depleted water as determined by the upwelling-downwelling cycle; and through its control of water column stratification and mixing. A seasonal decline in bottom DO concentrations of ˜1.2 ml l-1 occurs with a concurrent expansion of the bottom pool of oxygen depleted water in St Helena Bay. Upwelling of this water into the nearshore causes severe drops in DO concentration (<0.2 ml l-1), particularly during end-of-season upwelling, resulting in a significant narrowing of the habitable zone. Episodic anoxia through the entire water column is caused by localized degradation of red tides within the confines of the shallow nearshore environment. Oxygenation of the nearshore is achieved by ventilation of the water column particularly with the onset of winter mixing. No notable changes are evident in comparing recent measures of bottom DO concentrations in St Helena Bay to data collected in the late 1950s and early 1960s.

  15. Impact of reactive oxygen species on antioxidant capacity of male reproductive system.

    PubMed

    Riaz, Muhammad; Mahmood, Zahed; Shahid, Muhammad; Saeed, M Usman Qamar; Tahir, Imtiaz Mahmood; Shah, Sm Ali; Munir, Naveed; El-Ghorab, Ahmed

    2016-09-01

    The present research work was aimed to study the mutual interaction of reactive oxygen species (ROS) and basal cells antioxidant capacity in the male reproductive system and to further establish the association between selected heavy metals and stress markers. Total oxidant status (TOS) and total antioxidant status (TAS) of serum and seminal plasma were determined by automated photometric methods. The concentrations of Selenium (Se), Lead (Pb), and Cadmium (Cd) were determined by using atomic absorption spectrophotometer. The TOS was increased significantly (P <0.05) in seminal plasma as well as in the serum of the infertile group when compared with the fertile group. On the other hand, the TAS of the infertile group was found to be noticeably decreased (P <0.05) when compared with the TAS of the fertile group. Among the heavy metals, a noticeably lower concentration of Se was detected in the infertile group whereas markedly elevated levels of Cd and Pb were observed in the infertile group compared with the fertile group. Among the infertile group a significant inverse correlation (r = -0.521, P <0.05) was observed between Se and TOS and between Cd and Pb (r = -0.407, P <0.05). Contrarily among the infertile group a considerable positive relationship was established between Se and TAS (r = 0.507, P <0.05). It was concluded that the oxidant stress reduces the antioxidant activity in infertile men by elevating the production of ROS. A lower concentration of Se and elevated levels of Pb and Cd explain the individual's exposure to these heavy metals. The study also revealed that the heavy metal toxicity contributes significantly to male infertility.

  16. Optical oxygen sensing systems for drug discovery applications: Respirometric Screening Technology (RST)

    NASA Astrophysics Data System (ADS)

    Papkovsky, Dmitri B.; Hynes, James; Fernandes, Richard

    2005-11-01

    Quenched-fluorescence oxygen sensing allows non-chemical, reversible, real-time monitoring of molecular oxygen and rates of oxygen consumption in biological samples. Using this approach we have developed Respirometric Screening Technology (RST); a platform which facilitates the convenient analysis of cellular oxygen uptake. This in turn allows the investigation of compounds and processes which affect respiratory activity. The RST platform employs soluble phosphorescent oxygen-sensitive probes, which may be assessed in standard microtitter plates on a fluorescence plate reader. New formats of RST assays and time-resolved fluorescence detection instrumentation developed by Luxcel provide improvements in assay sensitivity, miniaturization and overall performance. RST has a diverse range of applications in drug discovery area including high throughput analysis of mitochondrial function; studies of mechanisms of toxicity and apoptosis; cell and animal based screening of compound libraries and environmental samples; and, sterility testing. RST has been successfully validated with a range of practical targets and adopted by several leading pharmaceutical companies.

  17. The study of excited oxygen molecule gas species production and quenching on thermal protection system materials

    NASA Technical Reports Server (NTRS)

    Nordine, Paul C.; Fujimoto, Gordon T.; Greene, Frank T.

    1987-01-01

    The detection of excited oxygen and ozone molecules formed by surface catalyzed oxygen atom recombination and reaction was investigated by laser induced fluorescence (LIF), molecular beam mass spectrometric (MBMS), and field ionization (FI) techniques. The experiment used partially dissociated oxygen flows from a microwave discharge at pressures in the range from 60 to 400 Pa or from an inductively coupled RF discharge at atmospheric pressure. The catalyst materials investigated were nickel and the reaction cured glass coating used for Space Shuttle reusable surface insulation tiles. Nonradiative loss processes for the laser excited states makes LIF detection of O2 difficult such that formation of excited oxygen molecules could not be detected in the flow from the microwave discharge or in the gaseous products of atom loss on nickel. MBMS experiments showed that ozone was a product of heterogeneous O atom loss on nickel and tile surfaces at low temperatures and that ozone is lost on these materials at elevated temperatures. FI was separately investigated as a method by which excited oxygen molecules may be conveniently detected. Partial O2 dissociation decreases the current produced by FI of the gas.

  18. Advances in reflective oxygen saturation monitoring with a novel in-ear sensor system: results of a human hypoxia study.

    PubMed

    Venema, Boudewijn; Blanik, Nikolai; Blazek, Vladimir; Gehring, Hartmut; Opp, Alexander; Leonhardt, Steffen

    2012-07-01

    Pulse oximetry is a well-established, noninvasive photoplethysmographic method to monitor vital signs. It allows us to measure cardiovascular parameters, such as heart rate and arterial oxygen saturation, and is considered an essential monitoring tool in clinical routine. However, since many of the conventional systems work in transmission mode, they can only be applied to the thinner or peripheral parts of the body, such as a finger tip. This has the major disadvantage that, in case of shock-induced centralization and a resulting drop in perfusion, such systems cannot ensure valid measurements. Therefore, we developed a reflective in-ear sensor system that can be worn in the ear channel like a headphone. Because the sensor is integrated in an ear mold and positioned very close to the trunk, reliable measurement is expected even in case of centralization. An additional advantage is that the sensor is comfortable to wear and has considerable resistance to motion artifacts. In this paper, we report on hypoxia studies with ten healthy participants which were performed to analyze the system with regard to the detection of heart rate and arterial oxygen saturation. It was shown earlier that, due to the high signal quality, heart rate can easily be detected. Using the conventional calculation principle, based on Beer-Lambert's law combined with a single-point calibration method, we now demonstrate that the detection of arterial oxygen saturation in the human ear canal is possible using reflective saturation sensors.

  19. A sterilization system using ultraviolet photochemical reactions based on nitrous oxide and oxygen gases.

    PubMed

    Ohnishi, Yasutaka; Matsumoto, Hiroyuki; Iwamori, Satoru

    2016-03-01

    Active oxygen species (AOS) generated under ultraviolet (UV) lamps can be applied for various industrial processes owing to extremely strong oxidative abilities. We have already reported on an application of the AOS for a sterilization process of microorganisms. Here, a sterilization method using active oxygen generated under ultraviolet (UV) lamps introducing nitrous oxide (N2O) and oxygen gases into a vacuum chamber was investigated. Nitrogen dioxide (NO2) gas was readily produced from N2O by UV photochemical reactions under the low-pressure mercury lamp and then used to sterilize medical devices. We compared the ability of the N2O gas to sterilize Geobacillus stearothermophilus spores with those of conventional methods. Successful sterilization of spores on various biological indicators was achieved within 60 min, not only in sterilization bags but also in a lumen device.

  20. The system Fe-Si-O: Oxygen buffer calibrations to 1,500K

    NASA Astrophysics Data System (ADS)

    Myers, J.; Eugster, H. P.

    1983-03-01

    The five solid-phase oxygen buffers of the system Fe-Si-O, iron-wuestite (IW), wuestite-magnetite (WM), magnetite-hematite (MH), quartz-iron-fayalite (QIF) and fayalite-magnetite-quartz (FMQ) have been recalibrated at 1 atm pressure and temperatures from 800° 1,300° C, using a thermogravimetric gas mixing furnace. The oxygen fugacity, f_{{text{O}}_{text{2}} } was measured with a CaO-doped ZrO2 electrode. Measurements were made also for wuestite solid solutions in order to determine the redox behavior of wuestites with O/Fe ratios varying from 1.05 to 1.17. For FMQ, additional determinations were carried out at 1 kb over a temperature range of 600° to 800° C, using a modified Shaw membrane. Results agree reasonably well with published data and extrapolations. The reaction parameters K, Δ G {r/o}, Δ H {r/o}, and Δ S {r/o}were calculated from the following log f_{{text{O}}_{text{2}} }/ T relations (T in K): 410_2004_Article_BF00371177_TeX2GIFE1.gif begin{gathered} {text{IW }}log f_{{text{O}}_{text{2}} } = - 26,834.7/T + 6.471left( { ± 0.058} right) \\ {text{ }}left( {{text{800}} - 1,260{text{ C}}} right), \\ {text{WM }}log f_{{text{O}}_{text{2}} } = - 36,951.3/T + 16.092left( { ± 0.045} right) \\ {text{ }}left( {{text{1,000}} - 1,300{text{ C}}} right), \\ {text{MH }}log f_{{text{O}}_{text{2}} } = - 23,847.6/T + 13.480left( { ± 0.055} right) \\ {text{ }}left( {{text{1,040}} - 1,270{text{ C}}} right), \\ {text{QIF }}log f_{{text{O}}_{text{2}} } = - 27,517.5/T + 6.396left( { ± 0.049} right) \\ {text{ }}left( {{text{960}} - 1,140{text{ C}}} right), \\ {text{FMQ }}log f_{{text{O}}_{text{2}} } = - 24,441.9/T + 8.290left( { ± 0.167} right) \\ {text{ }}left( {{text{600}} - 1,140{text{ C}}} right). \\ These experimentally determined reaction parameters were combined with published 298 K data to determine the parameters Gf, Hf, and Sf for the phases wuestite, magnetite, hematite, and fayalite from 298 K to the temperatures of the experiments. The T

  1. Safe-to-Fly Testing of the Guardian Angel Integrated Oxygen System (GAIOS)

    DTIC Science & Technology

    2013-07-01

    Specification : USP Oxygen Sample Eq Ser No : 81A01093 Tank Pressure : l , 200 psi Method Test CGA G- 4.3- 2000 Odor CGA G-4. 3- 2000 Purity...Specification : USP Oxygen Sample Eq Ser No : 82A01093 Tank Pressure : l , 200 psi Method Test CGA G- 4.3- 2000 Odor CGA G-4. 3- 2000 Purity (% vol...82A01093 Tank Pressure : l , 100 psi Method Test CGA G- 4.3- 2000 Odor CGA G-4. 3- 2000 Purity (% vol) CGA G- 4 . 3- 2000 Minor Constituents (By

  2. Results of the Test Program for Replacement of AK-225G Solvent for Cleaning NASA Propulsion Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Lowrey, Nikki M.; Mitchell, Mark A.

    2016-01-01

    Since the 1990's, when the Class I Ozone Depleting Substance chlorofluorocarbon-113 was banned, NASA's propulsion test facilities at Marshall Space Flight Center and Stennis Space Center have relied upon the solvent Asahiklin AK-225 (hydrochlorofluorocarbon-225ca/cb or HCFC-225ca/cb) and, more recently AK-225G (the single isomer form, HCFC-225cb) to safely clean and verify the cleanliness of large scale propulsion oxygen systems. Effective January 1, 2015, the production, import, export, and new use of Class II Ozone Depleting Substances, including AK-225G, was prohibited in the United States by the Clean Air Act. In 2012 through 2014, NASA test labs at MSFC, SSC, and Johnson Space Center's White Sands Test Facility collaborated to seek out, test, and qualify a solvent replacement for AK-225G that is both an effective cleaner and safe for use with oxygen systems. This paper summarizes the tests performed, results, and lessons learned.

  3. A binary concrete crack self-healing system containing oxygen-releasing tablet and bacteria and its Ca(2+)-precipitation performance.

    PubMed

    Zhang, J L; Wang, C G; Wang, Q L; Feng, J L; Pan, W; Zheng, X C; Liu, B; Han, N X; Xing, F; Deng, X

    2016-12-01

    A strategy to supply molecular oxygen for microbial calcium precipitation was developed for the first time. Firstly, a controlled oxygen-releasing tablet (ORT) containing CaO2 and lactic acid with a suitable ratio of 9:1 was developed. It can provide a stable oxygen supply and maintain pH in the range of 9.5-11.0 for 45 days while contacting with water. In the presence of oxygen, a self-healing bacterium H4 spores germinated more effectively and maintained high metabolic activity. Furthermore, H4 vegetative cells induced 50 % more calcium precipitation than that obtained without oxygen supply. Finally, a binary self-healing system containing bacterial spores and ORT was established. The calcium precipitation experiments showed that H4 in the binary self-healing system precipitated 27.5 mM calcium with oxygen supply after 32 days and dissolved oxygen (DO) concentration of the solution decreased from 15 to 4 mg l(-1), while only 6.9 mM calcium precipitation was obtained without oxygen supply. This work can disclose the effect of oxygen on microbial calcium precipitation and further lay a foundation for the establishment of ternary self-healing system containing bacteria, ORT, and nutrients, which will be promising for the self-healing of cracks deep inside the concrete structure.

  4. Organic carbon and dissolved oxygen budgets for a commerical-size, in-pond raceway system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Intensive production of Ictalurid catfish in the United States has increased over the past several years and a better understanding of the amount of organic carbon (OC) and dissolved oxygen (DO) in these culture environments is needed. Budgets for OC and DO were estimated over a production season (M...

  5. The Campylobacter jejuni RacRS system regulates fumarate utilization in a low oxygen environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The natural environment of the human pathogen Campylobacter jejuni is the gastrointestinal tract of warm blooded animals. In the gut, the availability of oxygen is limited; therefore, less efficient electron acceptors such as nitrate or fumarate are used by C. jejuni. C. jejuni has a highly branched...

  6. Oxygen uptake kinetics and energy system's contribution around maximal lactate steady state swimming intensity.

    PubMed

    Pelarigo, Jailton Gregório; Machado, Leandro; Fernandes, Ricardo Jorge; Greco, Camila Coelho; Vilas-Boas, João Paulo

    2017-01-01

    The purpose of this study was to examine the oxygen uptake ([Formula: see text]) kinetics and the energy systems' contribution at 97.5, 100 and 102.5% of the maximal lactate steady state (MLSS) swimming intensity. Ten elite female swimmers performed three-to-five 30 min submaximal constant swimming bouts at imposed paces for the determination of the swimming velocity (v) at 100%MLSS based on a 7 x 200 m intermittent incremental protocol until voluntary exhaustion to find the v associated at the individual anaerobic threshold. [Formula: see text] kinetics (cardiodynamic, primary and slow component phases) and the aerobic and anaerobic energy contributions were assessed during the continuous exercises, which the former was studied for the beginning and second phase of exercise. Subjects showed similar time delay (TD) (mean = 11.5-14.3 s) and time constant (τp) (mean = 13.8-16.3 s) as a function of v, but reduced amplitude of the primary component for 97.5% (35.7 ± 7.3 mL.kg.min-1) compared to 100 and 102.5%MLSS (41.0 ± 7.0 and 41.3 ± 5.4 mL.kg.min-1, respectively), and τp decreased (mean = 9.6-10.8 s) during the second phase of exercise. Despite the slow component did not occur for all swimmers at all swim intensities, when observed it tended to increase as a function of v. Moreover, the total energy contribution was almost exclusively aerobic (98-99%) at 97.5, 100 and 102.5%MLSS. We suggest that well-trained endurance swimmers with a fast TD and τp values may be able to adjust faster the physiological requirements to minimize the amplitude of the slow component appearance, parameter associated with the fatigue delay and increase in exhaustion time during performance, however, these fast adjustments were not able to control the progressive fatigue occurred slightly above MLSS, and most of swimmers reached exhaustion before 30min swam.

  7. Direct Measurements of Oxygen Gradients in Spheroid Culture System Using Electron Parametric Resonance Oximetry

    PubMed Central

    Langan, Laura M.; Dodd, Nicholas J. F.; Owen, Stewart F.; Purcell, Wendy M.; Jackson, Simon K.; Jha, Awadhesh N.

    2016-01-01

    Advanced in vitro culture from tissues of different origin includes three-dimensional (3D) organoid micro structures that may mimic conditions in vivo. One example of simple 3D culture is spheroids; ball shaped structures typically used as liver and tumour models. Oxygen is critically important in physiological processes, but is difficult to quantify in 3D culture: and the question arises, how small does a spheroid have to be to have minimal micro-environment formation? This question is of particular importance in the growing field of 3D based models for toxicological assessment. Here, we describe a simple non-invasive approach modified for the quantitative measurement and subsequent evaluation of oxygen gradients in spheroids developed from a non-malignant fish cell line (i.e. RTG-2 cells) using Electron Paramagnetic Resonance (EPR) oximetry. Sonication of the paramagnetic probe Lithium phthalocyanine (LiPc) allows for incorporation of probe particulates into spheroid during its formation. Spectra signal strength after incorporation of probe into spheroid indicated that a volume of 20 μl of probe (stock solution: 0.10 mg/mL) is sufficient to provide a strong spectra across a range of spheroid sizes. The addition of non-toxic probes (that do not produce or consume oxygen) report on oxygen diffusion throughout the spheroid as a function of size. We provide evidence supporting the use of this model over a range of initial cell seeding densities and spheroid sizes with the production of oxygen distribution as a function of these parameters. In our spheroid model, lower cell seeding densities (∼2,500 cells/spheroid) and absolute size (118±32 μm) allow control of factors such as pre-existing stresses (e.g. ∼ 2% normoxic/hypoxic interface) for more accurate measurement of treatment response. The applied methodology provides an elegant, widely applicable approach to directly characterize spheroid (and other organoid) cultures in biomedical and toxicological

  8. Comparison of Helzel and OxyLite Systems in the Measurements of Tumor Partial Oxygen Pressure (pO2)

    PubMed Central

    Wen, Bixiu; Urano, Muneyasu; Humm, John L.; Seshan, Venkatraman E.; Li, Gloria C.; Ling, C. Clifton

    2009-01-01

    It has been demonstrated in both experimental and human malignancies that hypoxic tumor cells are linked with aggressive disease phenotype. One of the methods to identify these cells is by direct physical measurement of tumor pO2. This study compared pO2 values measured with two systems, the Helzel Hypoximeter (successor of the polarographic Eppen-dorf electrode) and the Oxford-Optronix OxyLite (fiber-optic probe), in R3327-AT and R3327-AT/tkeGFP tumors. Partial oxygen pressure was measured in individual tumors with either system or in the same tumor with both systems. The similarities and discrepancies in pO2 measurements between the two systems were also investigated when tumor-bearing animals were breathing pure oxygen. Our data showed a considerable heterogeneity in pO2 values in each tumor using both the Helzel and OxyLite systems. Similar results were obtained with both systems for the mean and median pO2 values, and the distributions of pO2 values within the interval 0 < pO2 < 40 mmHg (the range important for defining tumor hypoxia) were found to be statistically equivalent However, the frequencies of high pO2 values (>40 mmHg) and zero values measured by the two systems were statistically significantly different. PMID:18159950

  9. Scaling laws for oxygen transport across the space-filling system of respiratory membranes in the human lung

    NASA Astrophysics Data System (ADS)

    Hou, Chen

    Space-filling fractal surfaces play a fundamental role in how organisms function at various levels and in how structure determines function at different levels. In this thesis, we develop a quantitative theory of oxygen transport to and across the surface of the highly branched, space-filling system of alveoli, the fundamental gas exchange unit (acinar airways), in the human lung. Oxygen transport in the acinar airways is by diffusion, and we treat the two steps---diffusion through the branched airways, and transfer across the alveolar membranes---as a stationary diffusion-reaction problem, taking into account that there may be steep concentration gradients between the entrance and remote alveoli (screening). We develop a renormalization treatment of this screening effect and derive an analytic formula for the oxygen current across the cumulative alveolar membrane surface, modeled as a fractal, space-filling surface. The formula predicts the current from a minimum of morphological data of the acinus and appropriate values of the transport parameters, through a number of power laws (scaling laws). We find that the lung at rest operates near the borderline between partial screening and no screening; that it switches to no screening under exercise; and that the computed currents agree with measured values within experimental uncertainties. From an analysis of the computed current as a function of membrane permeability, we find that the space-filling structure of the gas exchanger is simultaneously optimal with respect to five criteria. The exchanger (i) generates a maximum oxygen current at minimum permeability; (ii) 'wastes' a minimum of surface area; (iii) maintains a minimum residence time of oxygen in the acinar airways; (iv) has a maximum fault tolerance to loss of permeability; and (v) generates a maximum current increase when switching from rest to exercise.

  10. Field test of two high-pressure direct-contact downhole steam generators. Volume II. Oxygen/diesel system

    SciTech Connect

    Moreno, J.B.

    1983-07-01

    A field test of an oxygen/diesel fuel, direct contact steam generator has been completed. The field test, which was a part of Project DEEP STEAM and was sponsored by the US Department of Energy, involved the thermal stimulation of a well pattern in the Tar Zone of the Wilmington Oil Field. The activity was carried out in cooperation with the City of Long Beach and the Long Beach Oil Development Company. The steam generator was operated at ground level, with the steam and combustion products delivered to the reservoir through 2022 feet of calcium-silicate insulated tubing. The objectives of the test included demonstrations of safety, operational ease, reliability and lifetime; investigations of reservoir response, environmental impact, and economics; and comparison of those points with a second generator that used air rather than oxygen. The test was extensively instrumented to provide the required data. Excluding interruptions not attributable to the oxygen/diesel system, steam was injected 78% of the time. System lifetime was limited by the combustor, which required some parts replacement every 2 to 3 weeks. For the conditions of this particular test, the use of trucked-in LOX resulted in liess expense than did the production of the equivalent amount of high pressure air using on site compressors. No statistically significant production change in the eight-acre oxygen system well pattern occurred during the test, nor were any adverse effects on the reservoir character detected. Gas analyses during the field test showed very low levels of SOX (less than or equal to 1 ppM) in the generator gaseous effluent. The SOX and NOX data did not permit any conclusion to be drawn regarding reservoir scrubbing. Appreciable levels of CO (less than or equal to 5%) were measured at the generator, and in this case produced-gas analyses showed evidence of significant gas scrubbing. 64 figures, 10 tables.

  11. Effect of oxygen on the per‐cell extracellular electron transfer rate of Shewanella oneidensis MR‐1 explored in bioelectrochemical systems

    PubMed Central

    Lu, Mengqian; Chan, Shirley; Babanova, Sofia

    2016-01-01

    ABSTRACT Extracellular electron transfer (EET) is a mechanism that enables microbes to respire solid‐phase electron acceptors. These EET reactions most often occur in the absence of oxygen, since oxygen can act as a competitive electron acceptor for many facultative microbes. However, for Shewanella oneidensis MR‐1, oxygen may increase biomass development, which could result in an overall increase in EET activity. Here, we studied the effect of oxygen on S. oneidensis MR‐1 EET rates using bioelectrochemical systems (BESs). We utilized optically accessible BESs to monitor real‐time biomass growth, and studied the per‐cell EET rate as a function of oxygen and riboflavin concentrations in BESs of different design and operational conditions. Our results show that oxygen exposure promotes biomass development on the electrode, but significantly impairs per‐cell EET rates even though current production does not always decrease with oxygen exposure. Additionally, our results indicated that oxygen can affect the role of riboflavin in EET. Under anaerobic conditions, both current density and per‐cell EET rate increase with the riboflavin concentration. However, as the dissolved oxygen (DO) value increased to 0.42 mg/L, riboflavin showed very limited enhancement on per‐cell EET rate and current generation. Since it is known that oxygen can promote flavins secretion in S. oneidensis, the role of riboflavin may change under anaerobic and aerobic conditions. Biotechnol. Bioeng. 2017;114: 96–105. © 2016 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc. PMID:27399911

  12. Cold Helium Pressurization for Liquid Oxygen / Liquid Methane Propulsion Systems: Fully-Integrated Initial Hot-Fire Test Results

    NASA Technical Reports Server (NTRS)

    Morehead, R. L.; Atwell, M. J.; Melcher, J. C.; Hurlbert, E. A.

    2016-01-01

    A prototype cold helium active pressurization system was incorporated into an existing liquid oxygen (LOX) / liquid methane (LCH4) prototype planetary lander and hot-fire tested to collect vehicle-level performance data. Results from this hot-fire test series were used to validate integrated models of the vehicle helium and propulsion systems and demonstrate system effectiveness for a throttling lander. Pressurization systems vary greatly in complexity and efficiency between vehicles, so a pressurization performance metric was also developed as a means to compare different active pressurization schemes. This implementation of an active repress system is an initial sizing draft. Refined implementations will be tested in the future, improving the general knowledge base for a cryogenic lander-based cold helium system.

  13. Post-Flight Microbial Analysis of Samples from the International Space Station Water Recovery System and Oxygen Generation System

    NASA Technical Reports Server (NTRS)

    Birmele, Michele N.

    2011-01-01

    The Regenerative, Environmental Control and Life Support System (ECLSS) on the International Space Station (ISS) includes the the Water Recovery System (WRS) and the Oxygen Generation System (OGS). The WRS consists of a Urine Processor Assembly (UPA) and Water Processor Assembly (WPA). This report describes microbial characterization of wastewater and surface samples collected from the WRS and OGS subsystems, returned to KSC, JSC, and MSFC on consecutive shuttle flights (STS-129 and STS-130) in 2009-10. STS-129 returned two filters that contained fluid samples from the WPA Waste Tank Orbital Recovery Unit (ORU), one from the waste tank and the other from the ISS humidity condensate. Direct count by microscopic enumeration revealed 8.38 x 104 cells per mL in the humidity condensate sample, but none of those cells were recoverable on solid agar media. In contrast, 3.32 x lOs cells per mL were measured from a surface swab of the WRS waste tank, including viable bacteria and fungi recovered after S12 days of incubation on solid agar media. Based on rDNA sequencing and phenotypic characterization, a fungus recovered from the filter was determined to be Lecythophora mutabilis. The bacterial isolate was identified by rDNA sequence data to be Methylobacterium radiotolerans. Additional UPA subsystem samples were returned on STS-130 for analysis. Both liquid and solid samples were collected from the Russian urine container (EDV), Distillation Assembly (DA) and Recycle Filter Tank Assembly (RFTA) for post-flight analysis. The bacterium Pseudomonas aeruginosa and fungus Chaetomium brasiliense were isolated from the EDV samples. No viable bacteria or fungi were recovered from RFTA brine samples (N= 6), but multiple samples (N = 11) from the DA and RFTA were found to contain fungal and bacterial cells. Many recovered cells have been identified to genus by rDNA sequencing and carbon source utilization profiling (BiOLOG Gen III). The presence of viable bacteria and fungi from WRS

  14. Onboard Inert Gas Generation System/Onboard Oxygen Gas Generation System (OBIGGS/OBOGS) Study. Part 2; Gas Separation Technology--State of the Art

    NASA Technical Reports Server (NTRS)

    Reynolds, Thomas L.; Eklund, Thor I.; Haack, Gregory A.

    2001-01-01

    This purpose of this contract study task was to investigate the State of the Art in Gas Separation Technologies utilized for separating air into both nitrogen and oxygen gases for potential applications on commercial aircraft. The intended applications included: nitrogen gas for fuel tank inerting, cargo compartment fire protection, and emergency oxygen for passenger and crew use in the event of loss of cabin pressure. The approach was to investigate three principle methods of gas separation: Hollow Fiber Membrane (HFM), Ceramic Membrane (CM), and liquefaction: Total Atmospheric Liquefaction of Oxygen and Nitrogen (TALON). Additional data on the performance of molecular sieve pressure swing adsorption (PSA) systems was also collected and discussed. Performance comparisons of these technologies are contained in the body of the report.

  15. A mathematical model of metabolism and regulation provides a systems-level view of how Escherichia coli responds to oxygen

    PubMed Central

    Ederer, Michael; Steinsiek, Sonja; Stagge, Stefan; Rolfe, Matthew D.; Ter Beek, Alexander; Knies, David; Teixeira de Mattos, M. Joost; Sauter, Thomas; Green, Jeffrey; Poole, Robert K.; Bettenbrock, Katja; Sawodny, Oliver

    2014-01-01

    The efficient redesign of bacteria for biotechnological purposes, such as biofuel production, waste disposal or specific biocatalytic functions, requires a quantitative systems-level understanding of energy supply, carbon, and redox metabolism. The measurement of transcript levels, metabolite concentrations and metabolic fluxes per se gives an incomplete picture. An appreciation of the interdependencies between the different measurement values is essential for systems-level understanding. Mathematical modeling has the potential to provide a coherent and quantitative description of the interplay between gene expression, metabolite concentrations, and metabolic fluxes. Escherichia coli undergoes major adaptations in central metabolism when the availability of oxygen changes. Thus, an integrated description of the oxygen response provides a benchmark of our understanding of carbon, energy, and redox metabolism. We present the first comprehensive model of the central metabolism of E. coli that describes steady-state metabolism at different levels of oxygen availability. Variables of the model are metabolite concentrations, gene expression levels, transcription factor activities, metabolic fluxes, and biomass concentration. We analyze the model with respect to the production capabilities of central metabolism of E. coli. In particular, we predict how precursor and biomass concentration are affected by product formation. PMID:24723921

  16. Theory of Triplet Excitation Transfer in the Donor-Oxygen-Acceptor System: Application to Cytochrome b6f

    PubMed Central

    Petrov, Elmar G.; Robert, Bruno; Lin, Sheng Hsien; Valkunas, Leonas

    2015-01-01

    Theoretical consideration is presented of the triplet excitation dynamics in donor-acceptor systems in conditions where the transfer is mediated by an oxygen molecule. It is demonstrated that oxygen may be involved in both real and virtual intramolecular triplet-singlet conversions in the course of the process under consideration. Expressions describing a superexchange donor-acceptor coupling owing to a participation of the bridging twofold degenerate oxygen’s virtual singlet state are derived and the transfer kinetics including the sequential (hopping) and coherent (distant) routes are analyzed. Applicability of this theoretical description to the pigment-protein complex cytochrome b6f, by considering the triplet excitation transfer from the chlorophyll a molecule to distant β-carotene, is discussed. PMID:26488665

  17. Investigation of the Makeup, Source, and Removal Strategies for Total Organic Carbon in the Oxygen Generation System Recirculation Loop

    NASA Technical Reports Server (NTRS)

    Bowman, Elizabeth M.; Carpenter, Joyce; Roy, Robert J.; Van Keuren, Steve; Wilson, Mark E.

    2015-01-01

    Since 2007, the Oxygen Generation System (OGS) on board the International Space Station (ISS) has been producing oxygen for crew respiration via water electrolysis. As water is consumed in the OGS recirculating water loop, make-up water is furnished by the ISS potable water bus. A rise in Total Organic Carbon (TOC) was observed beginning in February, 2011, which continues through the present date. Increasing TOC is of concern because the organic constituents responsible for the TOC were unknown and had not been identified; hence their impacts on the operation of the electrolytic cell stack components and on microorganism growth rates and types are unknown. Identification of the compounds responsible for the TOC increase, their sources, and estimates of their loadings in the OGA as well as possible mitigation strategies are presented.

  18. Evaluation of alternatives for trichlorotrifluoroethane (CFC-113) to clean and verify liquid oxygen systems

    NASA Technical Reports Server (NTRS)

    Morris, Michelle L.

    1996-01-01

    NASA Langley Research Center (LARC) investigated several alternatives to the use of tri-chloro-tri-fluoroethane(CFC-113) in oxygen cleaning and verification. Alternatives investigated include several replacement solvents, Non-Destructive Evaluation (NDE) and Total Organic Carbon (TOC) analysis. Among the solvents, 1, 1-dichloro-1-fluoroethane (HCFC 141b) and di-chloro-penta-fluoro-propane (HCFC 225) are the most suitable alternatives for cleaning and verification. However, use of HCFC 141b is restricted, HCFC 225 introduces toxicity hazards, and the NDE and TOC methods of verification are not suitable for processes at LaRC. Therefore, the interim recommendation is to sparingly use CFC-113 for the very difficult cleaning tasks where safety is critical and to use HCFC 225 to clean components in a controlled laboratory environment. Meanwhile, evaluation must continue on now solvents and procedures to find one suited to LaRCs oxygen cleaning needs.

  19. When seeing is not believing: Oxygen on Ag(111), a simple adsorption system?

    NASA Astrophysics Data System (ADS)

    Michaelides, Angelos; Reuter, Karsten; Scheffler, Matthias

    2005-11-01

    A number of recent studies indicate that, under the oxygen rich conditions of oxidation catalysis, some transition metal catalysts may be covered by thin oxide overlayers. Moreover, it has been suggested that such ``surface-oxide'' layers are catalytically active, possibly more active than the pure metal surfaces as was traditionally assumed. This contemporary picture can be traced back to Ag catalysis, where over 30 years ago it was suggested that the top layer of Ag(111) reconstructed to an epitaxial Ag2O like overlayer upon exposure to oxygen [Rovida et al., Surf. Sci. 43, 230 (1974)]. Extensive experimental work, including scanning tunneling microscopy studies in which the oxide was apparently imaged with atomic resolution, as well as density-functional theory calculations, largely confirmed this interpretation. However, a review of published experimental data and new density-functional theory results presented here indicate that previous conclusions are significantly incomplete and that the structure of this original surface oxide must be reconsidered.

  20. Oxygen-Accelerated Decompression of Submarine Rescue and Diving Recompression System (SRDRS) Operators and Tenders

    DTIC Science & Technology

    2005-04-01

    gas. Hemoglobin and carboxyhemoglobin concentrations were measured by differential light absorption. All diver subjects completed two pre-dive... measure oxygen effects.16 Suzuki, et al., reported that diffusing capacity (DLco) and diffusing capacity referenced to lung volumes (DLcoNA) were more...Diffusing capacity for carbon monoxide (DLco) by the single-breath method. Alveolar volume (VA) was measured concomitantly using methane as the tracer

  1. Hypoxia tolerance and antioxidant defense system of juvenile jumbo squids in oxygen minimum zones

    NASA Astrophysics Data System (ADS)

    Trübenbach, Katja; Teixeira, Tatiana; Diniz, Mário; Rosa, Rui

    2013-10-01

    Jumbo squid (Dosidicus gigas) is a large oceanic squid endemic off the Eastern Tropical Pacific that undertakes diel vertical migrations into mesopelagic oxygen minimum zones. One of the expected physiological effects of such migration is the generation of reactive oxygen species (ROS) at the surface, promoted by the transition between hypoxia and reoxygenation states. The aim of this study was to investigate the energy expenditure rates and the antioxidant stress strategies of juvenile D. gigas under normoxia and hypoxia, namely by quantifying oxygen consumption rates, antioxidant enzyme activities [including superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST)], heat shock protein expression (Hsp70/Hsc70), and lipid peroxidation [malondialdehyde (MDA) levels]. A high significant decrease (68%) in squid's metabolic rates was observed during hypoxia (p<0.05). This process of metabolic suppression was followed by a significant increase in Hsp70/Hsc70 expression (p<0.05), which may be interpreted as a strategy to prevent post-hypoxic oxidative damage during the squid's night upwards migration to the surface ocean. On the other hand, in normoxia, the higher SOD and CAT activities seemed to be a strategy to cope with the reoxygenation process, and may constitute an integrated stress response at shallower depths. GST activity and MDA concentrations did not change significantly from normoxia to hypoxia (p>0.05), with the latter indicating no enhancement of lipid peroxidation (i.e. cellular damage) at the warmer and normoxic surface waters. The understanding of such physiological strategies that are linked to oxygen deprivation and reoxygenation phases may provide valuable information about how this species is quickly responding to the impacts of environmental stressors coupled with global climate change.

  2. Non-ODC Oxygen Line Cleaning for Use on DOD Weapons Systems

    DTIC Science & Technology

    2007-11-02

    distortion, cracking , crazing , blistering, embrittlement and decomposition temperature shift….refer to Test Methods D 471, D 543, D 1460, and Practice D...surface ships, and submarines. The substrates may be aluminum, stainless steel , or copper. Two alternative technologies were chosen for this project: an...is oxygen line cleaning of aerospace vehicles, surface ships, and submarines. The substrates may be aluminum, stainless steel , or copper. Table 1

  3. Development Status for a Combined Solid Oxide Co-Electrolyzer and Carbon Formation Reactor System for Oxygen Regeneration

    NASA Technical Reports Server (NTRS)

    Green, Robert D.; Matter, Paul H.; Holt, Chris; Beachy, Michael; Gaydos, James; Farmer, Serene C.; Setlock, John

    2016-01-01

    A critical component in spacecraft life support loop closure is the removal of carbon dioxide (CO2, produced by the crew) from the cabin atmosphere and chemical reduction of this CO2 to recover the oxygen. In 2015, we initiated development of an oxygen recovery system for life support applications consisting of a solid oxide co-electrolyzer (SOCE) and a carbon formation reactor (CFR). The SOCE electrolyzes a combined stream of carbon dioxide (CO2) and water (H2O) gas mixtures to produce synthesis gas (e.g., CO and H2 gas) and pure dry oxygen as separate products. This SOCE is being developed from a NASA GRC solid oxide fuel cell and stack design originally developed for aeronautics long-duration power applications. The CFR, being developed by pHMatter LLC, takes the CO and H2 output from the SOCE, and converts it primarily to solid carbon (C(s)) and H2O and CO2. Although the solid carbon accumulates in the CFR, the innovative design allows easy removal of the carbon product, requiring minimal crew member (CM) time and low resupply mass (1.0 kg/year/CM) for replacement of the solid carbon catalyst, a significant improvement over previous Bosch reactor approaches. In this work, we will provide a status of our Phase I efforts in the development and testing of both the SOCE and CFR prototype units, along with an initial assessment of the combined SOCE-CFR system, including a mass and power projections, along with an estimate of the oxygen recovery rate.

  4. Phenol degradation in heterogeneous system generating singlet oxygen employing light activated electropolymerized phenothiazines

    NASA Astrophysics Data System (ADS)

    Piwowar, Katarzyna; Blacha-Grzechnik, Agata; Bernas, Paulina; Zak, Jerzy

    2015-12-01

    Five selected amine-derivatives of phenothiazine were electropolymerized on an ITO/glass substrate and then used in the daylight-activated process to produce in situ singlet oxygen which degrades phenol in a solution. The phenothiazines were immobilized in a simple electrochemical procedure in an acidic solution which led to the formation of an ultrathin transparent polymeric film. All films obtained on the ITO substrate including azure A (AA), azure C (AC), methylene blue (MB), toluidine blue (TBO), and thionine (Th) had a comparable surface coverage at the level of picomoles/cm2. The activity of these materials was then compared and presented in terms of an efficiency of the phenol degradation process in an aqueous solution by photogenerated singlet oxygen. That efficiency was determined by the UV-vis spectroscopy employing a phenol/4-aminoantipyrine complex. All the phenothiazine ultrathin polymeric films were capable of generating the singlet oxygen in the aqueous solution under daylight activation, which was used in the consecutive process of phenol degradation. The highest efficiency at a level of 51.4% and 45.4% was found for the AC/ITO and MB/ITO layers, respectively.

  5. The disulfide relay of the intermembrane space of mitochondria: an oxygen-sensing system?

    PubMed

    Bihlmaier, Karl; Mesecke, Nikola; Kloeppel, Christine; Herrmann, Johannes M

    2008-12-01

    The intermembrane space of mitochondria contains many proteins that lack classical mitochondrial targeting sequences. Instead, these proteins often show characteristic patterns of cysteine residues that are critical for their accumulation in the organelle. Import of these proteins is catalyzed by two essential components, Mia40 and Erv1. Mia40 is a protein in the intermembrane space that directly binds newly imported proteins via disulfide bonds. By reorganization of these bonds, intramolecular disulfide bonds are formed in the imported proteins, which are thereby released from Mia40 into the intermembrane space. Because folded proteins are unable to traverse the import pore of the outer membrane, this leads to a permanent location of these proteins within the mitochondria. During this reaction, Mia40 becomes reduced and needs to be re-oxidized to regain its activity. Oxidation of Mia40 is carried out by Erv1, a conserved flavine adenine dinucleotide (FAD)-binding sulfhydryl oxidase. Erv1 directly interacts with Mia40 and shuttles electrons from reduced Mia40 to oxidized cytochrome c, from whence they flow through cytochrome oxidase to molecular oxygen. The connection of the disulfide relay with the respiratory chain not only significantly increases the efficiency of the oxidase activity, but also prevents the formation of potentially deleterious hydrogen peroxide. The oxidative activity of Erv1 strongly depends on the oxygen concentration in mitochondria. Erv1, therefore, may function as a molecular switch that adapts mitochondrial activities to the oxygen levels in the cell.

  6. Oxy-Mat™ Mattress System Development Utilizing Simultaneous Measurement of Interface Pressure and Deep Tissue Oxygen Saturation.

    PubMed

    Butler, Glenn J; Kenyon, David J; Gorenstein, Scott; Davenport, Thomas; Golembe, Edward; Lee, Bok; Vieweg, Jacques

    2015-05-01

    The development and management of pressure ulcers (PUs) among hospital and nursing home patients is one of the greatest preventable challenges to healthcare worldwide. For over 50 years, pressure mapping and subjective comfort has been the primary indicators for mattress selection. Our research demonstrates that mattress/patient interface pressure and relative blood/oxygen perfusion do not inversely correlate and pressure is not a meaningful, real-time indicator of tissue ischemia and risk of pressure ulcer development. Developed in our research is a real-time sensor system to simultaneously measure and record these parameters over the anatomical sites at risk for PUs. Measurements focused on the heel, sacrum, trochanter, ischium, scapula and occipital. A modified pressure mapping system is used for interface pressure measurements and integrated with multiple near-infrared sensors to measure specific deep tissue hemoglobin saturated oxygen or rSO2. Testing and mattress design development was done during the period of 2008 to present. Over 200 human tests of commercially available mattresses were conducted in supine, 30 degree, and 70 degree positions, ranging in times of up to four hours. During this time period, we utilized 20 test subjects-eight female and 12 male-with ages ranging from 18 to 65 years. The result of this proprietary off-loading device evaluation and design system shows that the new Oxy-Mat™ (Off-Loading Technologies, Tarrytown, NY) Non-Powered Mattress System consistently provides optimized tissue perfusion as measured by natural deep tissue oxygen saturation levels. In extensive laboratory and clinical evaluations, the Oxy-Mat™ was shown to be functionally superior to CMS Group 2 powered mattresses. Another outcome of our research was that a powered mattress system may not be appropriate for most sensate and semi-ambulatory patients. Further research is underway.

  7. Cold Helium Pressurization for Liquid Oxygen/Liquid Methane Propulsion Systems: Fully-Integrated Hot-Fire Test Results

    NASA Technical Reports Server (NTRS)

    Morehead, R. L.; Atwell, M. J.; Melcher, J. C.; Hurlbert, E. A.

    2016-01-01

    Hot-fire test demonstrations were successfully conducted using a cold helium pressurization system fully integrated into a liquid oxygen (LOX) / liquid methane (LCH4) propulsion system (Figure 1). Cold helium pressurant storage at near liquid nitrogen (LN2) temperatures (-275 F and colder) and used as a heated tank pressurant provides a substantial density advantage compared to ambient temperature storage. The increased storage density reduces helium pressurant tank size and mass, creating payload increases of 35% for small lunar-lander sized applications. This degree of mass reduction also enables pressure-fed propulsion systems for human-rated Mars ascent vehicle designs. Hot-fire test results from the highly-instrumented test bed will be used to demonstrate system performance and validate integrated models of the helium and propulsion systems. A pressurization performance metric will also be developed as a means to compare different active pressurization schemes.

  8. Using oxygen at home

    MedlinePlus

    Oxygen - home use; COPD - home oxygen; Chronic obstructive airways disease - home oxygen; Chronic obstructive lung disease - home oxygen; Chronic bronchitis - home oxygen; Emphysema - home oxygen; Chronic respiratory ...

  9. A flowing liquid test system for assessing the linearity and time-response of rapid fibre optic oxygen partial pressure sensors.

    PubMed

    Chen, R; Hahn, C E W; Farmery, A D

    2012-08-15

    The development of a methodology for testing the time response, linearity and performance characteristics of ultra fast fibre optic oxygen sensors in the liquid phase is presented. Two standard medical paediatric oxygenators are arranged to provide two independent extracorporeal circuits. Flow from either circuit can be diverted over the sensor under test by means of a system of rapid cross-over solenoid valves exposing the sensor to an abrupt change in oxygen partial pressure, P O2. The system is also capable of testing the oxygen sensor responses to changes in temperature, carbon dioxide partial pressure P CO2 and pH in situ. Results are presented for a miniature fibre optic oxygen sensor constructed in-house with a response time ≈ 50 ms and a commercial fibre optic sensor (Ocean Optics Foxy), when tested in flowing saline and stored blood.

  10. Is the scatter in nitrogen/oxygen of metal-poor systems real? Do H II regions become significantly self-enriched in oxygen?

    NASA Astrophysics Data System (ADS)

    Nava, Aida Hortensia

    In this dissertation, I addressed two independent problems. Problem 1 was to determine the extent of intrinsic scatter in the log(N/O) versus 12+log(O/H) diagram of dwarf emission-line galaxies with 12+log(O/H) <= 8.1 (hereafter, metal-poor systems), where O/H (oxygen to hydrogen) and N/O (nitrogen to oxygen) are number density ratios derived from the global HII region-like spectra of these systems. In order to assess the extent of intrinsic scatter among these systems, I computed 24 single-star HII region (H IIR) simulations with CLOUDY, using input stellar spectra modeled by D. Casebeer and D. Jevremovic with PHOENIX. The advantages of these simulations are: use of state- of-the-art stellar spectra, log(N/O) and log(C/O) fixed at -1.46 and -0.7 (which are published means of these systems, respectively), self-consistent stellar and nebular chemical compositions, and O/H as low as solar/50, i.e. , lower than any past work. The analysis of the 24 models shows that: (a) the uncertainties in the log(O/H) and log(N/O) derived from collisionally excited forbidden lines are reduced if the temperatures T e (N + ) and T e (O + ), used for deriving N + /H + and O + /H + respectively, are independent parameterizations of T e (O +2 ) [in general, T e (N + ) = T e (O + ) is assumed, but I show that T e (N + ) and T e (O + ) significantly diverge at low metallicity]; and (b) that the ionization correction factor (ICF) for obtaining N/O from N + /O + , is [left angle bracket]ICF[right angle bracket] = 1.08 ± 0.09 (in general, N/O=N + /O + is assumed). Adopting T e (N + ) != T e (O + ), the above ICF, and published de-reddened emission-line strengths, I re-derived the O/H and N/O ratios for a carefully selected sample of 68 metal-poor systems. For these systems: (1) the largest group of objects forms the well- known N/O plateau, with a value for the mean (and its statistical error) of - 1.43 (+.0084/-.0085); (2) the objects are distributed within a range in log(N/ O) of -1.54 to

  11. Multi-channel multi-distance broadband near-infrared spectroscopy system to measure the spatial response of cellular oxygen metabolism and tissue oxygenation

    PubMed Central

    Phan, Phong; Highton, David; Lai, Jonathan; Smith, Martin; Elwell, Clare; Tachtsidis, Ilias

    2016-01-01

    We present a multi-channel, multi-distance broadband near-infrared spectroscopy (NIRS) system with the capability of measuring changes in haemoglobin concentrations (Δ[HbO2], Δ[HHb]), oxidation state of cytochrome-c-oxidase (Δ[oxCCO]) and tissue oxygen saturation (TOI) in the adult human brain. The main components of the instrument are two customized spectrographs and two light sources. Each spectrograph is lens-based to improve light throughput, has a grating enhanced to optimise reflection in the near-infrared (NIR) spectral region and uses a front illuminated cooled CCD camera (−70° C) with a square chip dimension of 12.3 x 12.3 mm (512 x 512 pixels). Each light source uses a 50W halogen bulb with a gold plated mirror to increase the intensity of the NIR light. Each light source was connected to a custom-built bifurcated fibre bundle to create two source fibre bundles (3.2 mm diameter each). Each spectrograph received light input from another custom-built fibre bundle comprised of six individual bundles (one with 0.6 mm diameter and the other five with 1.5 mm diameter). All fibre bundles were fixed on a 3D printed optode holder (two light sources x two fibre bundles each = four probes; and two spectrographs x six fibre bundles each = 12 probes) that allowed 24 multi-distance channels across the forehead (six channels at 20 mm, three channels at 30 mm and 15 channels at 35 mm) and six TOI measurements. We demonstrated the use of the system in a cohort of nine healthy adult volunteers during prefrontal cortex functional activation using the Stroop task. We have observed functional responses identified as significant increase in Δ[HbO2], decrease in Δ[HHb] and increase in Δ[oxCCO] in five channels (out of 12), that overlay the left and right dorsolateral prefrontal cortices. There was no observable TOI functional response and we have shown small variations in TOI across different sites within the same subject and within the same site across subjects. PMID

  12. Multi-channel multi-distance broadband near-infrared spectroscopy system to measure the spatial response of cellular oxygen metabolism and tissue oxygenation.

    PubMed

    Phan, Phong; Highton, David; Lai, Jonathan; Smith, Martin; Elwell, Clare; Tachtsidis, Ilias

    2016-11-01

    We present a multi-channel, multi-distance broadband near-infrared spectroscopy (NIRS) system with the capability of measuring changes in haemoglobin concentrations (Δ[HbO2], Δ[HHb]), oxidation state of cytochrome-c-oxidase (Δ[oxCCO]) and tissue oxygen saturation (TOI) in the adult human brain. The main components of the instrument are two customized spectrographs and two light sources. Each spectrograph is lens-based to improve light throughput, has a grating enhanced to optimise reflection in the near-infrared (NIR) spectral region and uses a front illuminated cooled CCD camera (-70° C) with a square chip dimension of 12.3 x 12.3 mm (512 x 512 pixels). Each light source uses a 50W halogen bulb with a gold plated mirror to increase the intensity of the NIR light. Each light source was connected to a custom-built bifurcated fibre bundle to create two source fibre bundles (3.2 mm diameter each). Each spectrograph received light input from another custom-built fibre bundle comprised of six individual bundles (one with 0.6 mm diameter and the other five with 1.5 mm diameter). All fibre bundles were fixed on a 3D printed optode holder (two light sources x two fibre bundles each = four probes; and two spectrographs x six fibre bundles each = 12 probes) that allowed 24 multi-distance channels across the forehead (six channels at 20 mm, three channels at 30 mm and 15 channels at 35 mm) and six TOI measurements. We demonstrated the use of the system in a cohort of nine healthy adult volunteers during prefrontal cortex functional activation using the Stroop task. We have observed functional responses identified as significant increase in Δ[HbO2], decrease in Δ[HHb] and increase in Δ[oxCCO] in five channels (out of 12), that overlay the left and right dorsolateral prefrontal cortices. There was no observable TOI functional response and we have shown small variations in TOI across different sites within the same subject and within the same site across subjects.

  13. [Spectral analysis of oxygen radical in a synergistic system of pulsed discharge plasma/TiO2].

    PubMed

    Wang, Hui-Juan; Li, Jie; Chu, Jin-Yu

    2011-01-01

    Based on the synergistic effect of pulsed discharge plasma and titanium dioxide (TiO2) photocatalysis, a coupling system of pulsed discharge plasma/TiO2 was set up in the present paper, by using the ultraviolet radiation produced during the pulsed discharge process. TiO2 film immobilized on the glass beads was used as the photocatalyst in the synergistic system. In the research, the synergistic mechanism of pulsed discharge plasma and TiO2 photocatalysis was reviewed by the spectral diagnosis of oxygen radical (* O radical) produced in different reaction systems. The obtained results showed that the characteristic emission spectrum of * O radical could be observed at 777 nm and the corresponding transitions was 3p5 P --> 3s5 S. When air was used as bubbling gas, the relative emission intensity of * O radical recorded in the synergistic system was stronger than that in the plasma alone system, and the same result was also obtained when oxygen (O2) was used as bubbling gas. This result revealed that the photocatalytic activity of the immobilized TiO2 in the synergistic system could be induced by the ultraviolet radiation formed during the pulsed discharge process. In the systems of pulsed discharge plasma alone and pulsed discharge plasma combined with TiO2 photocatalysis, the relative emission intensity of * O radical in distilled water was stronger than that in phenol solutions. The results showed that * O radical was one of responsible radicals for phenol degradation in the pulsed discharge plasma alone system as well as the synergistic system.

  14. [Studies of the blood antioxidant system and oxygen-transporting properties of human erythrocytes during 105-day isolation].

    PubMed

    Brazhe, N A; Baĭzhumanov, A A; Parshina, E Iu; Iusipovich, A I; Akhalaia, M Ia; Iarlykova, Iu V; Labetskaia, O I; Ivanova, S M; Morukov, B V; Maksimov, G V

    2011-01-01

    Effects of strict 105-d isolation on blood antioxidant status, erythrocyte membrane processes and oxygen-binding properties of hemoglobin were studied in 6 male volunteers (25 to 40 y.o.) in ground-based simulation of a mission to Mars (experiment Mars-105). The parameters were measured using venous blood samples collected during BDC, on days 35, 70 and 105 of the experiment and on days 7 and 14-15 after its completion. Methods of biochemistry (determination of enzyme activity and thin-layer chromatography) and biophysical (laser interference microscopy, Raman spectroscopy) showed changes in relative content of lipid and phospholipid fractions suggesting growth of membrane microviscosity and increase in TBA-AP (active products of lipids peroxidation interacting with thiobarbituric acid). A significant increase in glucose-6-phosphate dehydrogenase and superoxide dismutase activities against reduction of catalase activity points to both reparative processes in erythrocytes and disbalance between the number of evolving active forms of oxygen and antioxidant protection mechanisms in cells. Hemoglobin sensitivity of oxygen and blood level of oxyhemoglobin were found to increase, too. It is presumed that adaptation of organism to stresses experienced during and after the experiment may destroy balance of the antioxidant protection systems which is conducive to oxidation of membrane phospholipids, alteration of their content, increase of membrane microviscosity and eventual failure of the gas-exchange function of erythrocytes.

  15. Prompt meningeal reconstruction mediated by oxygen-sensitive AKAP12 scaffolding protein after central nervous system injury

    PubMed Central

    Cha, Jong-Ho; Wee, Hee-Jun; Seo, Ji Hae; Ahn, Bum Ju; Park, Ji-Hyeon; Yang, Jun-Mo; Lee, Sae-Won; Lee, Ok-Hee; Lee, Hyo-Jong; Gelman, Irwin H.; Arai, Ken; Lo, Eng H.; Kim, Kyu-Won

    2015-01-01

    The meninges forms a critical epithelial barrier, which protects the central nervous system (CNS), and therefore its prompt reconstruction after CNS injury is essential for reducing neuronal damage. Meningeal cells migrate into the lesion site after undergoing an epithelial-mesenchymal transition (EMT) and repair the impaired meninges. However, the molecular mechanisms of meningeal EMT remain largely undefined. Here we show that TGF-β1 and retinoic acid (RA) released from the meninges, together with oxygen tension, could constitute the mechanism for rapid meningeal reconstruction. AKAP12 is an effector of this mechanism, and its expression in meningeal cells is regulated by integrated upstream signals composed of TGF-β1, RA and oxygen tension. Functionally, AKAP12 modulates meningeal EMT by regulating the TGF-β1-non-Smad-SNAI1 signalling pathway. Collectively, TGF-β1, RA and oxygen tension can modulate the dynamic change in AKAP12 expression, causing prompt meningeal reconstruction after CNS injury by regulating the transition between the epithelial and mesenchymal states of meningeal cells. PMID:25229625

  16. Fabrication and Characterization of Nanocarbon-Based Nanofluids by Using an Oxygen-Acetylene Flame Synthesis System

    NASA Astrophysics Data System (ADS)

    Teng, Tun-Ping; Wang, Wei-Ping; Hsu, Yu-Chun

    2016-06-01

    In this study, an oxygen-acetylene flame synthesis system was developed to fabricate nanocarbon-based nanofluids (NCBNFs) through a one-step synthesis method. Measured in liters per minute (LPM), the flame's fuel flows combined oxygen and acetylene at four ratios: 1.5/2.5 (P1), 1.0/2.5 (P2), 0.5/2.5 (P3), and 0/2.5 (P4). The flow rate of cooling water (base fluid) was fixed at 1.2 LPM to produce different nanocarbon-based materials (NCBMs) and various concentrations of NCBNFs. Tests and analyses were conducted for determining the morphology of NCBMs, NCBM material, optical characteristics, the production rate, suspension performance, average particle size, zeta potential, and other relevant basic characteristics of NCBNFs to understand the characteristics and materials of NCBNFs produced through different process parameters (P1-P4). The results revealed that the NCBMs mainly had flaky and spherical morphologies and the diameters of the spherical NCBMs measured approximately 20-30 nm. X-ray diffraction and Raman spectroscopy revealed that the NCBMs contained graphene oxide (GO) and amorphous carbon (AC) when the oxygen flow rate was lower than 1.0 LPM. In addition, the NCBMs contained reduced GO, crystalline graphite (graphite-2H), and AC when the oxygen flow rate was higher than 1.0 LPM. The process parameters of P1, P2, P3, and P4 resulted in NCBMs produced at concentrations of 0.010, 0.013, 0.040, and 0.023 wt%, respectively, in NCBNFs. All the NCBNFs exhibited non-Newtonian and shear-thinning rheological properties. The P4 ratio showed the highest enhancement rate of thermal conductivity for NCBNFs, at a rate 4.85 % higher than that of water.

  17. Fabrication and Characterization of Nanocarbon-Based Nanofluids by Using an Oxygen-Acetylene Flame Synthesis System.

    PubMed

    Teng, Tun-Ping; Wang, Wei-Ping; Hsu, Yu-Chun

    2016-12-01

    In this study, an oxygen-acetylene flame synthesis system was developed to fabricate nanocarbon-based nanofluids (NCBNFs) through a one-step synthesis method. Measured in liters per minute (LPM), the flame's fuel flows combined oxygen and acetylene at four ratios: 1.5/2.5 (P1), 1.0/2.5 (P2), 0.5/2.5 (P3), and 0/2.5 (P4). The flow rate of cooling water (base fluid) was fixed at 1.2 LPM to produce different nanocarbon-based materials (NCBMs) and various concentrations of NCBNFs. Tests and analyses were conducted for determining the morphology of NCBMs, NCBM material, optical characteristics, the production rate, suspension performance, average particle size, zeta potential, and other relevant basic characteristics of NCBNFs to understand the characteristics and materials of NCBNFs produced through different process parameters (P1-P4). The results revealed that the NCBMs mainly had flaky and spherical morphologies and the diameters of the spherical NCBMs measured approximately 20-30 nm. X-ray diffraction and Raman spectroscopy revealed that the NCBMs contained graphene oxide (GO) and amorphous carbon (AC) when the oxygen flow rate was lower than 1.0 LPM. In addition, the NCBMs contained reduced GO, crystalline graphite (graphite-2H), and AC when the oxygen flow rate was higher than 1.0 LPM. The process parameters of P1, P2, P3, and P4 resulted in NCBMs produced at concentrations of 0.010, 0.013, 0.040, and 0.023 wt%, respectively, in NCBNFs. All the NCBNFs exhibited non-Newtonian and shear-thinning rheological properties. The P4 ratio showed the highest enhancement rate of thermal conductivity for NCBNFs, at a rate 4.85 % higher than that of water.

  18. Data acquisition and control system with a programmable logic controller (PLC) for a pulsed chemical oxygen-iodine laser

    NASA Astrophysics Data System (ADS)

    Yu, Haijun; Li, Guofu; Duo, Liping; Jin, Yuqi; Wang, Jian; Sang, Fengting; Kang, Yuanfu; Li, Liucheng; Wang, Yuanhu; Tang, Shukai; Yu, Hongliang

    2015-02-01

    A user-friendly data acquisition and control system (DACS) for a pulsed chemical oxygen -iodine laser (PCOIL) has been developed. It is implemented by an industrial control computer,a PLC, and a distributed input/output (I/O) module, as well as the valve and transmitter. The system is capable of handling 200 analogue/digital channels for performing various operations such as on-line acquisition, display, safety measures and control of various valves. These operations are controlled either by control switches configured on a PC while not running or by a pre-determined sequence or timings during the run. The system is capable of real-time acquisition and on-line estimation of important diagnostic parameters for optimization of a PCOIL. The DACS system has been programmed using software programmable logic controller (PLC). Using this DACS, more than 200 runs were given performed successfully.

  19. A hybrid plasma technology life support system for the generation of oxygen on Mars: Considerations on materials and geometry

    NASA Astrophysics Data System (ADS)

    Gruenwald, J.

    2016-06-01

    As there is a growing interest in conducting human missions to Mars, the need for suitable life support systems becomes more and more important. The reliability of such systems has to increase with the duration of manned missions. Furthermore the maintenance requirements have to be low in order to ensure their efficient use over a long period of time. A proposal for a hybrid life support system that is based on plasma technology for the creation of oxygen from the dissociation of carbon dioxide is given in this paper. The main focus lies on geometrical considerations regarding the optimal shape of the main reactor chamber as well as on suitable materials, which are most promising for the construction of such a system.

  20. 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.

  1. Oxygen Therapy

    MedlinePlus

    ... stored as a gas or liquid in special tanks. These tanks can be delivered to your home and contain ... they won’t run out of oxygen. Portable tanks and oxygen concentrators may make it easier for ...

  2. Effects on optical systems from interactions with oxygen atoms in low earth orbits

    NASA Technical Reports Server (NTRS)

    Peters, P. N.; Swann, J. T.; Gregory, J. C.

    1986-01-01

    Modifications of material surface properties due to interactions with ambient atomic oxygen have been observed on surfaces facing the orbital direction in low earth orbits. Some effects are very damaging to surface optical properties while some are more subtle and even beneficial. Most combustible materials are heavily etched, and some coatings, such as silver and osmium, are seriously degraded or removed as volatile oxides. The growth of oxide films on metals and semiconductors considered stable in dry air was measured. Material removal, surface roughness, reflectance, and optical densities are reported. Effects of temperature, contamination, and overcoatings are noted.

  3. A New Oxygen Barometer for Solar System Basaltic Glasses Based on Vanadium Valence

    NASA Technical Reports Server (NTRS)

    Karner, J. M.; Sutton, S. R.; Papike, S. R.; Delaney, J. S.; Shearer, C. K.; Newville, M.; Eng, P.; Rivers, M.; Dyar, M. D.

    2004-01-01

    The determination of oxidation conditions for basaltic magmas derived by the melting of planetary mantles is critical to our understanding of the nature and evolution of planetary interiors. Yet, these determinations are compromised in terrestrial and especially extraterrestrial basalts by our analytical and computational methods for estimating oxygen fugacity (fO2). For example, mineralogical barometers (1, 2) can be reduced in effectiveness by subsolidus re-equilibration of mineral assemblages, inversion of mineralogical data to melt characteristics, and deviations of the natural mineral compositions from ideal thermodynamic parameters.

  4. Pharmacologic synergism of ocular ketorolac and systemic caffeine citrate in rat oxygen-induced retinopathy

    PubMed Central

    Aranda, Jacob V.; Cai, Charles L.; Ahmad, Taimur; Bronshtein, Vadim; Sadeh, Jonathan; Valencia, Gloria B.; Lazzaro, Douglas R.; Beharry, Kay D.

    2016-01-01

    Background: Caffeine or ketorolac decrease the risk of retinopathy of prematurity and may act synergistically to improve beneficial effect. Combination of caffeine (Caff) and ketorolac (Keto) to prevent oxygen-induced retinopathy was studied. Methods: Newborn rats exposed to room air (RA) or intermittent hypoxia (IH) consisting of 12% O2 during hyperoxia (50% O2) from birth (P0) had single daily IP injections of Caff from P0-P13 or saline; and/or ocular Keto (Acuvail, 0.45% ophthalmic solution) administered subcutaneously over the eyes from P5-P7. Pups were studied at P14 or placed in RA for recovery from IH (IHR) until P21. Eyes were examined for neovascularization, histopathology, growth factors, and VEGF-signaling genes. Results: Severe retinal damage noted during IHR in the untreated groups evidenced by hemorrhage, neovascularization, and oxygen-induced retinopathy (OIR) pathologies were prevented with Keto/Caff treatment. Keto and/or Caff treatment in IH also promoted retinal neural development evidenced by eye opening (92%, P < 0.001 vs. 31% in the placebo-treated IH group). No corneal pathologies were noted with Keto. Conclusion. Caff or Keto given individually reduced retinal neovascularization, but the two drugs given together prevented severe OIR. PMID:27438224

  5. Detecting, visualizing and quantitating the generation of reactive oxygen species in an amoeba model system.

    PubMed

    Zhang, Xuezhi; Soldati, Thierry

    2013-11-05

    Reactive oxygen species (ROS) comprise a range of reactive and short-lived, oxygen-containing molecules, which are dynamically interconverted or eliminated either catalytically or spontaneously. Due to the short life spans of most ROS and the diversity of their sources and subcellular localizations, a complete picture can be obtained only by careful measurements using a combination of protocols. Here, we present a set of three different protocols using OxyBurst Green (OBG)-coated beads, or dihydroethidium (DHE) and Amplex UltraRed (AUR), to monitor qualitatively and quantitatively various ROS in professional phagocytes such as Dictyostelium. We optimised the beads coating procedures and used OBG-coated beads and live microscopy to dynamically visualize intraphagosomal ROS generation at the single cell level. We identified lipopolysaccharide (LPS) from E. coli as a potent stimulator for ROS generation in Dictyostelium. In addition, we developed real time, medium-throughput assays using DHE and AUR to quantitatively measure intracellular superoxide and extracellular H2O2 production, respectively.

  6. V-T relaxation of vibrationally excited singlet oxygen molecule in the EOIL systems

    NASA Astrophysics Data System (ADS)

    Torbin, A. P.; Heaven, M. C.; Azyazov, V. N.

    2017-01-01

    Kinetics of vibrationally-excited singlet oxygen O2(a1Δ,v) molecule have been examined using pulsed laser technique.O2(a1Δ,v) molecules were produced by the pulsed 266 nm laser photolysis of ozone. The kinetics of O2(a1Δ) quenching were followed by observing the 1268 nm fluorescence of the O2 a1Δ-X3Σ transition. It has been found that the loss of O2(a1Δ,v) in the O(3P)/O3/N2 mixture is carried out both in chemical and in V-T process. We observed that the vibrational excitation of singlet oxygen molecule enhances the rate of reaction between O2(a1Δ,v) and O3 molecules. The rate constant of this process was estimated to be in the range 10-12-10-11 cm3/s. Rate constant of O2(a,v=1) quenching by CO2 was found to be (1.03±0.07)×10-14 cm3/s.

  7. A mesoporous catalytic membrane architecture for lithium-oxygen battery systems.

    PubMed

    Ryu, Won-Hee; Gittleson, Forrest S; Schwab, Mark; Goh, Tenghooi; Taylor, André D

    2015-01-14

    Controlling the mesoscale geometric configuration of catalysts on the oxygen electrode is an effective strategy to achieve high reversibility and efficiency in Li-O2 batteries. Here we introduce a new Li-O2 cell architecture that employs a catalytic polymer-based membrane between the oxygen electrode and the separator. The catalytic membrane was prepared by immobilization of Pd nanoparticles on a polyacrylonitrile (PAN) nanofiber membrane and is adjacent to a carbon nanotube electrode loaded with Ru nanoparticles. During oxide product formation, the insulating PAN polymer scaffold restricts direct electron transfer to the Pd catalyst particles and prevents the direct blockage of Pd catalytic sites. The modified Li-O2 battery with a catalytic membrane showed a stable cyclability for 60 cycles with a capacity of 1000 mAh/g and a reduced degree of polarization (∼ 0.3 V) compared to cells without a catalytic membrane. We demonstrate the effects of a catalytic membrane on the reaction characteristics associated with morphological and structural features of the discharge products via detailed ex situ characterization.

  8. Impact of an autologous oxygenating matrix culture system on rat islet transplantation outcome.

    PubMed

    Schaschkow, A; Mura, C; Bietiger, W; Peronet, C; Langlois, A; Bodin, F; Dissaux, C; Bruant-Rodier, C; Pinget, M; Jeandidier, N; Juszczak, M T; Sigrist, S; Maillard, E

    2015-06-01

    Disruption of the pancreatic islet environment combined with the decrease in oxygen supply that occurs during isolation leads to poor islet survival. The aim of this study was to validate the benefit of using a plasma-based scaffold supplemented with perfluorodecalin to improve islet transplantation outcome. Rat islets were cultured in three conditions: i) control group, ii) plasma based-matrix (P-matrix), and iii) P-matrix supplemented with emulsified perfluorodecalin. After 24 h culture, matrix/cell contacts (Integrinβ1, p-FAK/FAK, p-Akt/Akt), survival (caspase 3, TUNEL, FDA/PI), function, and HIF-1α translocation were assessed. Afterwards, P-matrices were dissolved and the islets were intraportally transplanted. Graft function was monitored for 31 days with glycaemia and C-peptide follow up. Inflammation was assessed by histology (macrophage and granulocyte staining) and thrombin/anti-thrombin complex measurement. Islet survival correlated with an increase in integrin, FAK, and Akt activation in P-matrices and function was maintained. Perfluorodecalin supplementation decreased translocation of HIF-1α in the nucleus and post-transplantation islet structure was better preserved in P-matrices, but a quicker activation of IBMIR resulted in early loss of graft function. "Oxygenating" P-matrices provided a real benefit to islet survival and resistance in vivo. However, intraportal transplantation is not suitable for this kind of culture due to IBMIR; thus, alternative sites must be explored.

  9. Franck-Condon Factors, R-Centroids Electronic Transition Moments, and Einstein Coefficients for Many Nitrogen and Oxygen Band Systems

    DTIC Science & Technology

    1992-02-01

    Box 92500 P.O. Box 109 Los Angeles, CA 90009 Logan, UT 84321 February 1992 D TIC Technical Report FEB8199U CONTRACT No. DNA 001-88-C- 0046 Approved for...Factors, R-Centroids, Electronic Transition Moments, and Einstein Coefficients for Many Nitrogen and C - DNA 001-88-C- 0046 Oxygen Band Systems PE 62715H 6...5.02E+02 6.56402 7.561+01’ 7.261402 2.30E+02 1.151+02 7.971+02 8.87E+02 4.59E+02 11 .1620 .1675 .1733 .1793 . 1857 .1925 .1997 .2073 .2153 .2239 .2330

  10. Engineering development program of a closed aluminum-oxygen semi-cell system for an unmanned underwater vehicle: An update

    NASA Technical Reports Server (NTRS)

    Gregg, Dane W.; Hall, Susan E.

    1995-01-01

    Most emerging unmanned undersea vehicle (UUV) missions require significantly longer range and endurance than is achievable with existing battery technology. The Aluminum-Oxygen (Al-O2) semi-cell is a candidate technology capable of providing a significant improvement in endurance compared to the silver-zinc battery technology currently used in UUVs and compares favorably to other proposed UUV power systems not only in performance, but also in safety and logistics. An Al-O2 semi-cell system is under development by Loral Defense Systems-Akron (Loral) for the ARPA/Navy 44 in. diameter UUV test vehicle. The power plant consists of a cell stack, gas management, oxygen storage, electrolyte management, coolant and controller subsystems, designed to replace the existing silver-zinc battery and meet existing weight, volume, electrical and thermal requirements, therefore minimizing modifications to the UUV. A detailed system design is complete. A component and material endurance test to evaluate compatibility and reliability of various material arid components is complete. Sub scale (Short stack) system testing is completed. A full-scale demonstration unit is now under construction in the second half of 1995. The full scale demonstration test will simulate environmental conditions of the operational system. This paper summarizes the results of the extensive short stack and endurance test programs, describes the plan for full-scale testing, and concludes with a brief discussions of future directions for this technology. This program is sponsored by ARPA Maritime Systems Technology Office under NASA contract NAS3-26715.

  11. Validity of Outcome Prediction Scoring Systems in Korean Patients with Severe Adult Respiratory Distress Syndrome Receiving Extracorporeal Membrane Oxygenation Therapy.

    PubMed

    Lee, Seunghyun; Yeo, Hye Ju; Yoon, Seong Hoon; Lee, Seung Eun; Cho, Woo Hyun; Jeon, Doo Soo; Kim, Yun Seong; Son, Bong Soo; Kim, Do Hyung

    2016-06-01

    Recently, several prognostic scoring systems for patients with severe acute respiratory distress syndrome (ARDS) requiring extracorporeal membrane oxygenation (ECMO) have been published. The aim of this study was to validate the established scoring systems for outcome prediction in Korean patients. We retrospectively reviewed the data of 50 patients on ECMO therapy in our center from 2012 to 2014. A calculation of outcome prediction scoring tools was performed and the comparison across various models was conducted. In our study, the overall hospital survival was 46% and successful weaning rate was 58%. The Predicting Death for Severe ARDS on V-V ECMO (PRESERVE) score showed good discrimination of mortality prediction for patients on ECMO with AUC of 0.80 (95% CI 0.66-0.90). The respiratory extracorporeal membrane oxygenation survival prediction (RESP) score and simplified acute physiology score (SAPS) II score also showed fair prediction ability with AUC of 0.79 (95% CI 0.65-0.89) and AUC of 0.78 (95% CI 0.64-0.88), respectively. However, the ECMOnet score failed to predict mortality with AUC of 0.51 (95% CI 0.37-0.66). When evaluating the predictive accuracy according to optimal cut-off point of each scoring system, RESP score had a best specificity of 91.3% and 66.7% of sensitivity, respectively. This study supports the clinical usefulness of the prognostic scoring tools for severe ARDS with ECMO therapy when applying to the Korean patients receiving ECMO.

  12. [Apneic oxygenation].

    PubMed

    Alekseev, A V; Vyzhigina, M A; Parshin, V D; Fedorov, D S

    2013-01-01

    Recent technological advances in thoracic and tracheal surgery make the anaesthesiologist use different respiratory techniques during the operation. Apneic oxygenation is a one of alternative techniques. This method is relatively easy in use, does not require special expensive equipment and is the only possible technique in several clinical situations when other respiratory methods are undesirable or cannot be used. However there is no enough information about apneic oxygenation in Russian. This article reviews publications about apneic oxygenation. The review deals with experiments on diffusion respiration in animals, physiological changes during apneic oxygenation in man and defines clinical cases when apneic oxygenation can be used.

  13. 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.

  14. Inhibition of reactive oxygen species in hypothalamic paraventricular nucleus attenuates the renin–angiotensin system and proinflammatory cytokines in hypertension

    SciTech Connect

    Su, Qing; Qin, Da-Nian; Wang, Fu-Xin; Ren, Jun; Li, Hong-Bao; Zhang, Meng; Yang, Qing; Miao, Yu-Wang; Yu, Xiao-Jing; Qi, Jie; Zhu, Zhiming; Zhu, Guo-Qing; Kang, Yu-Ming

    2014-04-15

    Aims: To explore whether reactive oxygen species (ROS) scavenger (tempol) in the hypothalamic paraventricular nucleus (PVN) attenuates renin–angiotensin system (RAS) and proinflammatory cytokines (PICs), and decreases the blood pressure and sympathetic activity in angiotensin II (ANG II)-induced hypertension. Methods and results: Male Sprague–Dawley rats were infused intravenously with ANG II (10 ng/kg per min) or normal saline (NS) for 4 weeks. These rats were treated with bilateral PVN infusion of oxygen free radical scavenger tempol (TEMP, 20 μg/h) or vehicle (artificial cerebrospinal fluid, aCSF) for 4 weeks. ANG II infusion resulted in increased mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA). These ANG II-infused rats also had higher levels of gp91{sup phox} (a subunit of NAD(P)H oxidase), angiotensin-converting enzyme (ACE), and interleukin-1beta (IL-1β) in the PVN than the control animals. Treatment with PVN infusion of TEMP attenuated the overexpression of gp91{sup phox}, ACE and IL-1β within the PVN, and decreased sympathetic activity and MAP in ANG II-infused rats. Conclusion: These findings suggest that ANG II infusion induces elevated PICs and oxidative stress in the PVN, which contribute to the sympathoexcitation in hypertension. Inhibition of reactive oxygen species in hypothalamic paraventricular nucleus attenuates the renin–angiotensin system, proinflammatory cytokines and oxidative stress in ANG II-induced hypertension. - Highlights: • The effect of chronic inhibiting PVN superoxide on hypertension was investigated. • ANG II infusion induced increased proinflammatory cytokines and superoxide in PVN. • ANG II infusion resulted in oxidative stress, sympathoexcitation and hypertension. • Chronic inhibiting PVN superoxide attenuates RAS and cytokines in hypertension.

  15. Thermochemical and Kinetics of Hydrazine Dehydrogenation by an Oxygen Atom in Hydrazine-Rich Systems: A Dimer Model.

    PubMed

    Spada, Rene F K; Ferrão, Luiz F A; Roberto-Neto, Orlando; Lischka, Hans; Machado, Francisco B C

    2015-12-24

    The kinetics of the reaction of N2H4 with oxygen depends sensitively on the initial conditions used. In oxygen-rich systems, the rate constant shows a conventional positive temperature dependence, while in hydrazine-rich setups the dependence is negative in certain temperature ranges. In this study, a theoretical model is presented that adequately reproduces the experimental results trend and values for hydrazine-rich environment, consisting of the hydrogen abstraction from the hydrazine (N2H4) dimer by an oxygen atom. The thermochemical properties of the reaction were computed using two quantum chemical approaches, the coupled cluster theory with single, double, and noniterative triple excitations (CCSD(T)) and the M06-2X DFT approach with the aug-cc-pVTZ and the maug-cc-pVTZ basis sets, respectively. The kinetic data were calculated with the improved canonical variational theory (ICVT) using a dual-level methodology to build the reaction path. The tunneling effects were considered by means of the small curvature tunneling (SCT) approximation. Potential wells on both sides of the reaction ((N2H4)2 + O → N2H4···N2H3 + OH) were determined. A reaction path with a negative activation energy was found leading, in the temperature range of 250-423 K, to a negative dependence of the rate constant on the temperature, which is in good agreement with the experimental measurements. Therefore, the consideration of the hydrazine dimer model provides significantly improved agreement with the experimental data and should be included in the mechanism of the global N2H4 combustion process, as it can be particularly important in hydrazine-rich systems.

  16. Measuring tissue oxygenation

    NASA Technical Reports Server (NTRS)

    Soyemi, Olusola O. (Inventor); Soller, Babs R. (Inventor); Yang, Ye (Inventor)

    2009-01-01

    Methods and systems for calculating tissue oxygenation, e.g., oxygen saturation, in a target tissue are disclosed. In some embodiments, the methods include: (a) directing incident radiation to a target tissue and determining reflectance spectra of the target tissue by measuring intensities of reflected radiation from the target tissue at a plurality of radiation wavelengths; (b) correcting the measured intensities of the reflectance spectra to reduce contributions thereto from skin and fat layers through which the incident radiation propagates; (c) determining oxygen saturation in the target tissue based on the corrected reflectance spectra; and (d) outputting the determined value of oxygen saturation.

  17. Separate and combined effects of Cu and Cd on seedling growth and active oxygen metabolism system of Trifolium repens L.

    PubMed

    Chu, Ling; Liu, Deng-Yi; Wang, You-Bao; Ding, Jia-Hong; Wang, Li-Long

    2006-09-01

    Pot-culture experiments were used to examine the individual and combined effects of Cu and Cd pollutants on Trifolium repens L. seedlings, both on their growth and their active oxygen metabolism system, mainly superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activities. The results showed that the negative action took place at low concentrations of Cu (less than 500 ppm) and Cd (less than 0.5 ppm), which had no obvious effects on the seedlings' growth. However, as the concentrations of Cu and Cd increased (500-3000 ppm and 0.5-50 ppm respectively), synergistic activities was observed, showing obvious negative effects (P less than 0.05). Compared with the control samples, the seedlings affected by Cu and Cd pollutants were shorter and smaller, their fresh/dry weight and content of soluble protein decreased drastically, their leaf electric conductivity increased, and the contents of their leaf pigments decreased. Chlorophyll a was more sensitive than chlorophyll b to Cu and Cd pollutants, and chlorophyll b was more sensitive than carotenoid. It was also shown that the active oxygen metabolism of T. repens seedlings was destroyed by high amounts of Cu and Cd, the balance of the anti-oxidase system was broken, and the CAT and SOD activities noticeably decreased while POD activity evidently increased. Cd had a more noticeable effect on seedling growth than Cu.

  18. Results of the Test Program for Replacement of AK-225G Solvent for Cleaning NASA Propulsion Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Lowrey, Nikki M.; Mitchell, Mark A.

    2016-01-01

    Since the 1990's, when the Class I Ozone Depleting Substance (ODS) chlorofluorocarbon-113 (CFC-113) was banned, NASA's propulsion test facilities at Marshall Space Flight Center (MSFC) and Stennis Space Center (SSC) have relied upon the solvent AsahiKlin AK-225 (hydrochlorofluorocarbon-225ca/cb or HCFC-225ca/cb) and, more recently AK-225G (the single isomer form, HCFC-225cb) to safely clean and verify the cleanliness of large scale propulsion oxygen systems. Effective January 1, 2015, the production, import, export, and new use of Class II Ozone Depleting Substances, including AK-225G, was prohibited in the United States by the Clean Air Act. In 2012 through 2014, NASA test labs at MSFC, SSC, and Johnson Space Center's White Sands Test Facility (WSTF) collaborated to seek out, test, and qualify a solvent replacement for AK-225G that is both an effective cleaner and safe for use with oxygen systems. This paper summarizes the tests performed, results, and lessons learned.

  19. Evaluation of a humidified nasal high-flow oxygen system, using oxygraphy, capnography and measurement of upper airway pressures.

    PubMed

    Ritchie, J E; Williams, A B; Gerard, C; Hockey, H

    2011-11-01

    In this study, we evaluated the performance of a humidified nasal high-flow system (Optiflow, Fisher and Paykel Healthcare) by measuring delivered FiO, and airway pressures. Oxygraphy, capnography and measurement of airway pressures were performed through a hypopharyngeal catheter in healthy volunteers receiving Optiflow humidified nasal high flow therapy at rest and with exercise. The study was conducted in a non-clinical experimental setting. Ten healthy volunteers completed the study after giving informed written consent. Participants received a delivered oxygen fraction of 0.60 with gas flow rates of 10, 20, 30, 40 and 50 l/minute in random order FiO2, F(E)O2, F(E)CO2 and airway pressures were measured. Calculation of FiO2 from F(E)O2 and F(E)CO2 was later performed. Calculated FiO2 approached 0.60 as gas flow rates increased above 30 l/minute during nose breathing at rest. High peak inspiratory flow rates with exercise were associated with increased air entrainment. Hypopharyngeal pressure increased with increasing delivered gas flow rate. At 50 l/minute the system delivered a mean airway pressure of up to 7.1 cm H20. We believe that the high gas flow rates delivered by this system enable an accurate inspired oxygen fraction to be delivered. The positive mean airway pressure created by the high flow increases the efficacy of this system and may serve as a bridge to formal positive pressure systems.

  20. Establishment of a total liquid ventilation system using saline-based oxygen micro/nano-bubble dispersions in rats.

    PubMed

    Kakiuchi, Kenta; Matsuda, Kenichi; Harii, Norikazu; Sou, Keitaro; Aoki, Junko; Takeoka, Shinji

    2015-09-01

    Micro/nano-bubbles are practical nanomaterials designed to increase the gas content in liquids. We attempted to use oxygen micro/nano-bubble dispersions as an oxygen-rich liquid as a means for total liquid ventilation. To determine the oxygen content in the bubble dispersion, a new method based on a spectrophotometric change between oxy- and deoxy-hemoglobin was established. The oxygen micro/nano-bubble dispersion was supplied to an experimental total ventilation liquid in anesthetic rats. Though the amount of dissolving oxygen was as low as 6 mg/L in physiological saline, the oxygen content in the oxygen micro/nano-bubble dispersion was increased to 45 mg/L. The positive correlation between the oxygen content and the life-saving time under liquid ventilation clearly indicates that the life-saving time is prolonged by increasing the oxygen content in the oxygen micro/nano-bubble dispersion. This is the first report indicating that the oxygen micro/nano-bubbles containing a sufficient amount of oxygen are useful in producing oxygen-rich liquid for the process of liquid ventilation.

  1. Singlet oxygen-sensitized delayed emissions from hydrogen peroxide/gallic acid/potassium ferricyanide systems containing organic solvents

    NASA Astrophysics Data System (ADS)

    Ishii, Hiroshi; Tsukino, Kazuo; Sekine, Masahiko; Nakata, Munetaka

    2009-06-01

    Fourier-transform chemiluminescence spectra of H 2O 2/gallic acid/K 3[Fe(CN) 6] systems containing organic solvents were measured. Emission bands with peaks around 530 and 700 nm were observed in systems containing solvents with a carbonyl group such as N, N-dimethylformamide, and those with a hydroxyl group such as methanol, respectively. The relative band intensities depended strongly on the concentration of these organic solvents. The emission species are attributed to gallic acid-ferricyanide complexes excited by energy transfer from singlet oxygen dimol, ( 1O 2) 2. The effects of organic solvents are interpreted in terms of intermolecular interactions of gallic acid-ferricyanide complexes, water molecules and organic solvents.

  2. Type III secretion system expression in oxygen-limited Pseudomonas aeruginosa cultures is stimulated by isocitrate lyase activity

    PubMed Central

    Chung, Jade C. S.; Rzhepishevska, Olena; Ramstedt, Madeleine; Welch, Martin

    2013-01-01

    Pseudomonas aeruginosa is an opportunistic human pathogen and a common cause of chronic infections in individuals with cystic fibrosis (CF). Oxygen limitation was recently reported to regulate the expression of a major virulence determinant in P. aeruginosa, the type III secretion system (T3SS). Here, we show that expression of the T3SS in oxygen-limited growth conditions is strongly dependent on the glyoxylate shunt enzyme, isocitrate lyase (ICL; encoded by aceA), which was previously shown to be highly expressed in CF isolates. ICL-dependent regulation of the T3SS did not alter the expression level of the master transcriptional regulator, ExsA, but did affect expression of the T3 structural proteins, effectors and regulators (ExsC, ExsD and ExsE). An aceA mutant displayed enhanced biofilm formation during anaerobic growth, which suggested that AceA-dependent modulation of type III secretion might impinge upon the RetS/LadS signalling pathways. Indeed, our data suggest that RetS is able to mediate some of its effects through AceA, as expression of aceA in trans partially restored T3SS expression in a retS mutant. Our findings indicate that AceA is a key player in the metabolic regulation of T3SS expression during oxygen-limited growth of P. aeruginosa. To the best of our knowledge, this is the first demonstration that the T3SS can be regulated by factors that do not affect ExsA expression levels. PMID:23363478

  3. Monitoring Cerebral Oxygenation in Neonates: An Update

    PubMed Central

    Dix, Laura Marie Louise; van Bel, Frank; Lemmers, Petra Maria Anna

    2017-01-01

    Cerebral oxygenation is not always reflected by systemic arterial oxygenation. Therefore, regional cerebral oxygen saturation (rScO2) monitoring with near-infrared spectroscopy (NIRS) is of added value in neonatal intensive care. rScO2 represents oxygen supply to the brain, while cerebral fractional tissue oxygen extraction, which is the ratio between rScO2 and systemic arterial oxygen saturation, reflects cerebral oxygen utilization. The balance between oxygen supply and utilization provides insight in neonatal cerebral (patho-)physiology. This review highlights the potential and limitations of cerebral oxygenation monitoring with NIRS in the neonatal intensive care unit. PMID:28352624

  4. Replacement of Hydrochlorofluorocarbon (HCFC) -225 Solvent for Cleaning and Verification Sampling of NASA Propulsion Oxygen Systems Hardware, Ground Support Equipment, and Associated Test Systems

    NASA Technical Reports Server (NTRS)

    Burns, H. D.; Mitchell, M. A.; McMillian, J. H.; Farner, B. R.; Harper, S. A.; Peralta, S. F.; Lowrey, N. M.; Ross, H. R.; Juarez, A.

    2015-01-01

    Since the 1990's, NASA's rocket propulsion test facilities at Marshall Space Flight Center (MSFC) and Stennis Space Center (SSC) have used hydrochlorofluorocarbon-225 (HCFC-225), a Class II ozone-depleting substance, to safety clean and verify the cleanliness of large scale propulsion oxygen systems and associated test facilities. In 2012 through 2014, test laboratories at MSFC, SSC, and Johnson Space Center-White Sands Test Facility collaborated to seek out, test, and qualify an environmentally preferred replacement for HCFC-225. Candidate solvents were selected, a test plan was developed, and the products were tested for materials compatibility, oxygen compatibility, cleaning effectiveness, and suitability for use in cleanliness verification and field cleaning operations. Honewell Soltice (TradeMark) Performance Fluid (trans-1-chloro-3,3, 3-trifluoropropene) was selected to replace HCFC-225 at NASA's MSFC and SSC rocket propulsion test facilities.

  5. Silver phosphate/graphitic carbon nitride as an efficient photocatalytic tandem system for oxygen evolution.

    PubMed

    Yang, Xiaofei; Tang, Hua; Xu, Jingsan; Antonietti, Markus; Shalom, Menny

    2015-04-24

    Herein, we show the facile synthesis of an efficient silver phosphate/graphitic carbon nitride (Ag3 PO4 /g-C3 N4 ) photocatalyst for oxygen production and pollutant degradation by using electrostatically driven assembly and ion-exchange processes. The composite materials demonstrate a sheet-like C3 N4 structure, decorated with different Ag3 PO4 particles sizes. Detailed analysis of the reactions mechanism by electron-spin resonance and radical-capture agents strongly imply the formation of an in situ Z-scheme by the evolution of small silver nanoparticles in the interface of the materials under illumination. The Ag nanoparticles improve charge separation within the composite material by acting as a storage and recombination center for electrons and holes from Ag3 PO4 and C3 N4 , respectively. In addition, the photostability of Ag3 PO4 is enhanced relative to that of the bulk materials, which results in a stabilized heterojunction. We believe that this work provides new insight into the operation mechanism of composite photocatalysts for water splitting and opens the possibility for advanced photocatalysis based on the higher oxidation power of Ag3 PO4 .

  6. Strontium and oxygen isotopic profiles through 3 km of hydrothermally altered oceanic crust in the Reykjanes Geothermal System, Iceland

    NASA Astrophysics Data System (ADS)

    Marks, N. E.; Zierenberg, R. A.; Schiffman, P.

    2010-12-01

    The Iceland Deep Drilling Program well of opportunity RN-17 was drilled 3 km into a section of hydrothermally altered basaltic crust in the Reykjanes geothermal system in Iceland. The system is located on the landward extension of the Mid-Atlantic Ridge, and the circulating hydrothermal fluid is modified seawater, making Reykjanes a useful analogue for mid-oceanic ridge hydrothermal systems. Whole rock oxygen isotope ratios range from -0.13 to 3.61‰, which are significantly depleted relative to fresh MORB (5.8±0.2‰). If oxygen isotope exchange between fluid and rock proceeded under equilibrium in a closed system, the bulk of the exchange must have occurred in the presence of a meteoric- as opposed to seawater-derived fluid. The concentrations of Sr in the altered basalt range from well below to well above concentrations in fresh rock, and appear to be strongly correlated with the dominant alteration mineralogy, although there is no correlation with 87Sr/86Sr isotopic ratios. Whole rock Sr isotopic ratios ranged from 0.70329 in the least altered crystalline basalt, to 0.70609 in the most altered hyaloclastite samples; there is no correlation with depth. Sr isotopic variation in epidote grains measured by laser ablation MC-ICP-MS ranged from 0.70353 to 0.70731. Three depth intervals have distinctive isotopic signatures, at 1000 m, 1350 m, and 2000 m depth, where 87Sr/86Sr ratios are elevated (mean value >0.7050) relative to background levels (mean altered basalt value ~0.7042). These areas are proximal to feed zones, and the 1350 m interval directly overlies the transition from dominantly extrusive to intrusive lithologies. Strontium and oxygen isotope data indicate that the greenschist-altered basalts were in equilibrium with modified hydrothermal fluids at a relatively high mean water/rock mass ratios (generally in the range 1-3), and require the presence of both meteoric- and seawater-derived recharge fluids at various stages in the hydrothermal history.

  7. Meteoric water in normal fault systems: Oxygen and hydrogen isotopic measurements on authigenic phases in brittle fault rocks

    NASA Astrophysics Data System (ADS)

    Haines, S. H.; Anderson, R.; Mulch, A.; Solum, J. G.; Valley, J. W.; van der Pluijm, B. A.

    2009-12-01

    The nature of fluid circulation systems in normal fault systems is fundamental to understanding the nature of fluid movement within the upper crust, and has important implications for the on-going controversy about the strength of faults. Authigenic phases in clay gouges and fault breccias record the isotopic signature of the fluids they formed in equilibrium with, and can be used to understand the ‘plumbing system’ of brittle fault environments. We obtained paired oxygen and hydrogen isotopic measurements on authigenic illite and/or smectite in clay gouge from normal faults in two geologic environments, 1.) low-angle normal faults (Ruby Mountains detachment, NV; Badwater Turtleback, CA; Panamint range-front detachment; CA; Amargosa detachment; CA; Waterman Hills detachment, CA), and 2.) An intracratonic high-angle normal fault (Moab Fault, UT). All authigenic phases in these clay gouges are moderately light isotopically with respect to oxygen (illite δ18O -2.0 - + 11.5 ‰ SMOW, smectite δ18O +3.6 and 17.9 ‰) and very light isotopically with respect to hydrogen (illite δD -148 to -98 ‰ SMOW, smectite δD -147 to -92 ‰). Fluid compositions calculated from the authigenic clays at temperatures of 50 - 130 ○C (as indicated by clay mineralogy) indicate that both illite and smectite in normal fault clay gouge formed in the presence of near-pristine to moderately-evolved meteoric fluids and that igneous or metamorphic fluids are not involved in clay gouge formation in these normal fault settings. We also obtained paired oxygen and hydrogen isotopic measurements on chlorites derived from footwall chlorite breccias in 4 low-angle normal fault detachment systems (Badwater and Mormon Point Turtlebacks, CA, the Chemehuevi detachment, CA, and the Buckskin-Rawhide detachment, AZ). All chlorites are isotopically light to moderately light with respect to oxygen (δ18O +0.29 to +8.1 ‰ SMOW) and very light with respect to hydrogen (δD -97 to -113 ‰) and indicate

  8. 75 FR 12713 - Airworthiness Directives; AVOX Systems and B/E Aerospace Oxygen Cylinders as Installed on Various...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-17

    .../E Aerospace Oxygen Cylinders as Installed on Various 14 CFR Part 23 and CAR 3 Airplanes AGENCY... and B/E Aerospace oxygen cylinders, as installed on various 14 CFR part 23 or CAR 3 airplanes. This proposed AD would require inspecting for and removing substandard oxygen cylinders from the airplane....

  9. Ion Microprobe Measurements of Comet Dust and Implications for Models of Oxygen Isotope Heterogeneity in the Solar System

    NASA Technical Reports Server (NTRS)

    Snead, C. J.; McKeegan, K. D.; Keller, L. P.; Messenger, S.

    2017-01-01

    ]. These studies have been largely focused on the coarse-grained terminal particles extracted from aerogel collectors; hypervelocity capture into aerogel resulted in fine-grained material that was melted and intimately mixed with the SiO2 capture medium. Hypervelocity impacts into Al foils surrounding the aerogel tiles produced impact craters that captured material from the impactor without significant oxygen contamination, allowing for analysis of both the coarse and fine-grained components of the Wild 2 dust. To date, no particles with definitive hydrated mineralogy have been observed in Stardust samples, though this may be a result of alteration due to hypervelocity capture. High-carbon hydrated CS-IDPs have been suggested as resulting from the aqueous alteration of CP-IDPs [7], and may retain evidence for interaction with O-17, O-18-enriched "cometary" water predicted by CO self-shielding. Here we present results of oxygen isotope measurements of twelve Stardust foil craters and four C-rich hydrated IDPs [8, 9], and discuss implications for models of oxygen isotope heterogeneity in the early solar system.

  10. Spontaneous ultraweak photon emission imaging of oxidative metabolic processes in human skin: effect of molecular oxygen and antioxidant defense system

    NASA Astrophysics Data System (ADS)

    Rastogi, Anshu; Pospíšil, Pavel

    2011-09-01

    All living organisms emit spontaneous ultraweak photon emission as a result of cellular metabolic processes. In this study, the involvement of reactive oxygen species (ROS) formed as the byproduct of oxidative metabolic processes in spontaneous ultraweak photon emission was studied in human hand skin. The effect of molecular oxygen and ROS scavengers on spontaneous ultraweak photon emission from human skin was monitored using a highly sensitive photomultiplier tube and charged coupled device camera. When spontaneous ultraweak photon emission was measured under anaerobic conditions, the photon emission was decreased, whereas under hyperaerobic condition the enhancement in photon emission was observed. Spontaneous ultraweak photon emission measured after topical application of glutathione, α-tocopherol, ascorbate, and coenzyme Q10 was observed to be decreased. These results reveal that ROS formed during the cellular metabolic processes in the epidermal cells play a significant role in the spontaneous ultraweak photon emission. It is proposed that spontaneous ultraweak photon emission can be used as a noninvasive tool for the temporal and spatial monitoring of the oxidative metabolic processes and intrinsic antioxidant system in human skin.

  11. n-Propyl gallate activates hypoxia-inducible factor 1 by modulating intracellular oxygen-sensing systems.

    PubMed

    Kimura, Motohide; Takabuchi, Satoshi; Tanaka, Tomoharu; Murata, Miyahiko; Nishi, Kenichiro; Oda, Seiko; Oda, Tomoyuki; Kanai, Michiyuki; Fukuda, Kazuhiko; Kizaka-Kondoh, Shinae; Adachi, Takehiko; Takabayashi, Arimichi; Semenza, Gregg L; Hirota, Kiichi

    2008-04-01

    HIF-1 (hypoxia-inducible factor 1) is a master regulator of cellular adaptive responses to hypoxia. The expression and transcriptional activity of the HIF-1alpha subunit is stringently controlled by intracellular oxygen tension through the action of prolyl and asparaginyl hydroxylases. In the present study we demonstrate that PG (n-propyl gallate) activates HIF-1 and expression of its downstream target genes under normoxic conditions in cultured cells and in mice. The stability and transcriptional activity of HIF-1alpha are increased by PG. PG treatment inhibits the interaction between HIF-1alpha and VHL (von Hippel-Lindau protein) and promotes the interaction between HIF-1alpha and p300, indicating that PG inhibits the activity of both prolyl and asparaginyl HIF-1alpha hydroxylases. We conclude that PG activates HIF-1 and enhances the resultant gene expression by directly affecting the intracellular oxygen sensing system in vitro and in vivo and that PG represents a lead compound for the development of a non-toxic activator of HIF-1.

  12. System-level approach to studying oxygen stress and acclimation of Shewanella oneidensis to growth under aerobic conditions

    NASA Astrophysics Data System (ADS)

    Beliaev, A.

    2008-12-01

    Systems-level approaches have been proven extremely useful in elucidating the mechanisms involved in stress response and acclimation of microorganisms to different environments. Recent studies of Shewanella oneidensis, a dissimilatory metal reducer catalyzing biogeochemical cycling of Fe and Mn, demonstrate that this facultatively aerobic bacterium is inhibited by high concentrations of oxygen. Physiological and genomic studies demonstrated that growth under aerobic conditions triggers autoaggregation of S. oneidensis leading to significant physiological and morphological changes which are consistent with biofilm mode of growth. Global transcriptome profiling of the aggregates revealed coordinated upregulation of various attachment and adhesion factors which is governed through coordinate regulation by the RpoS, SpoIIA, and Crp transcription factors. The aerobic aggregated cells also revealed increased expression of putative anaerobic electron transfer and homologs of metal reduction genes. The experimental evidence indicates that aggregate formation in S. oneidensis may serve as an alternative or an addition to biochemical detoxification to reduce the oxidative stress associated with production of reactive oxygen species during aerobic metabolism while facilitating the development of hypoxic conditions within the aggregate interior.

  13. Zooplankton associated with the oxygen minimum zone system in the northern upwelling region of Chile during March 2000

    NASA Astrophysics Data System (ADS)

    Escribano, Ruben; Hidalgo, Pamela; Krautz, Cristina

    2009-07-01

    Zooplankton in the coastal upwelling region off northern Chile may play a significant biogeochemical role by promoting carbon flux into the subsurface OMZ (oxygen minimum zone). This work identifies the dominant zooplankton species inhabiting the area influenced by the OMZ in March 2000 off Iquique (20°S, northern Chile). Abundance and vertical distribution studies revealed 17 copepod and 9 euphausiid species distributed between the surface and 600 m at four stations sampled both by day and by night. Some abundant species remained in the well-oxygenated upper layer (30 m), with no evidence of diel vertical migration, apparently restricted by a shallow (40-60 m) oxycline. Other species, however, were found closely associated with the OMZ. The large-sized copepod Eucalanus inermis was found below the oxycline and performed diel vertical migrations into the OMZ, whereas the very abundant Euphausia mucronata performed extensive diel vertical migrations between the surface waters and the core of the OMZ (200 m), even crossing it. A complete assessment of copepods and euphausiids revealed that the whole sampled water column (0-600 m) is occupied by distinct species having well-defined habitats, some of them within the OMZ. Ontogenetic migrations were evident in Eucalanidae and E. mucronata. Estimates of species biomass showed a substantial (>75% of total zooplankton biomass) daily exchange of C between the photic layer and the OMZ. Both E. inermis and E. mucronata can actively exchange about 37.8 g C m -2 d -1 between the upper well-oxygenated (0-60 m) layer and the deeper (60-600 m) OMZ layer. This migrant biomass may contribute about 7.2 g C m -2 d -1 to the OMZ system through respiration, mortality, and production of fecal pellets within the OMZ. This movement of zooplankton in and out of the OMZ, mainly as a result of the migratory behavior of E. mucronata, suggests a very efficient mechanism for introducing large amounts of freshly produced carbon into the OMZ

  14. Failure of glutamate dehydrogenase system to predict oxygenation state of human skeletal muscle.

    PubMed

    Katz, A; Spencer, M K; Sahlin, K

    1990-07-01

    In a recent study, the total tissue contents of glutamate (Glu), ammonium (NH+4), and 2-oxoglutarate (2-OG) were used to estimate changes in the mitochondrial redox state ([NAD+]/[NADH]) of contracting skeletal muscle with intact circulation [Am. J. Physiol. 253 (Cell Physiol. 22): C263-C268, 1987]. These metabolites participate in the glutamate dehydrogenase (GDH) reaction, which, based on a number of assumptions, theoretically enables calculation of the mitochondrial redox state as follows (brackets indicate concentrations): [NAD+]/[NADH] = ([NH+4] [2-OG])/[( Glu]Kapp), where Kapp is the apparent equilibrium constant for GDH. The purpose of this study was to determine whether changes in the total tissue contents of Glu, NH+4, and 2-OG could be used to predict a reduction of the mitochondrial redox state in anoxic skeletal muscle. Anoxia was induced in the quadriceps femoris muscle by 10 min of circulatory occlusion (low metabolic rate) and isometric contraction to fatigue (high metabolic rate). The mean (+/- SE) value for the metabolite ratio ([NH+4][2-OG]/[Glu]) at rest was 6 +/- 3 mmol/kg dry wt (x 10(-4]. No significant change occurred after circulatory occlusion (4 +/- 2 x 10(-4); P greater than 0.05), whereas an almost 60-fold increase was observed after isometric contraction (P less than 0.05). Because the muscle was anoxic under both conditions, a significant decrease in the metabolite ratio should have occurred. These data demonstrate that changes in total tissue contents of Glu, NH+4, and 2-OG cannot be used to estimate changes in the redox and oxygenation state of mitochondria in intact human skeletal muscle.

  15. Improvement of tumor response to photodynamic therapy by manipulation of tumor oxygenation in an in-vivo model system

    NASA Astrophysics Data System (ADS)

    Chen, Qun; Huang, Zheng; Chen, Hua; Shapiro, Howard; Beckers, Jill; Hetzel, Fred W.

    2002-09-01

    Photodynamic therapy (PDT) requires molecular oxygen during light irradiation in order to generate reactive oxygen species. Tumor hypoxia, either pre-existing or induced by PDT, can severely hamper the effectiveness of PDT treatment. Lowering the light irradiation dose rate or fractionating a light dose may improve cell kill of PDT induced hypoxic cells, but will have no effect on pre-existing hypoxic cells. In this study, hyper-oxygenation technique was used during PDT to overcome hypoxia. C3H mice with transplanted mammary carcinoma tumors were injected with 12.5 mg/kg Photofrin and irradiated with 630 nm laser light 24 hours later. Tumor oxygenation was manipulated by subjecting the animals to 3 atp hyperbaric oxygen or normobaric oxygen during PDT light irradiation. The results show a significant improvement in tumor response when PDT was delivered during hyper-oxygenation. With hyper-oxygenation, up to 80% of treated tumors showed no re-growth after 60 days. In comparison, only 20% of tumors treated while animals breathed room air did not re-grow. To explore the effect of hyper-oxygenation on tumor oxygenation, tumor pO2 was measured with microelectrodes positioned in pre-existing hypoxic regions before and during the PDT. The results show that hyper-oxygenation may oxygenate pre-existing hypoxic cells and compensate for oxygen depletion induced by PDT light irradiation. In conclusion, hyper-oxygenation may provide effective ways to improve PDT treatment efficiency by oxygenating both pre-existing and treatment induced cell hypoxia.

  16. Phase equilibria, crystal structure and oxygen content of intermediate phases in the Y–Ba–Co–O system

    SciTech Connect

    Urusova, A.S.; Cherepanov, V.A. Aksenova, T.V.; Gavrilova, L.Ya.; Kiselev, E.A.

    2013-06-01

    The phase equilibria in the Y–Ba–Co–O system were systematically studied at 1373 K in air. The intermediate phases formed in the Y–Ba–Co–O system at 1373 K in air were: YBaCo₂O5+δ, YBaCo₄O₇ and BaCo1–yYyO3–δ (0.09≤y≤0.42). It was shown that YBaCo₂O5+δ possesses tetragonal structure with the 3aₚ×3aₚ×2aₚ superstructure (sp. gr. P4/mmm). High-temperature X-ray diffraction analysis of the YBaCo₂O5+δ in the temperature range from 298 K up to 1073 K under Po₂=0.21 atm has not shown any phase transformations. The value of oxygen content for the YBaCo₂O5+δ at room temperature was estimated as 5.40 and at 1323 K it was equal to 5.04. Thermal expansion of sample shows a linear characteristics and the average thermal expansion coefficient (TEC) is about 13.8×10⁻⁶, K⁻¹ in the temperature range 298–1273 K. The homogeneity range and crystal structure of the BaCo1–yYyO3–δ (0.09≤y≤0.42) solid solutions were determined by X-ray diffraction of quenched samples. All BaCo1–yYyO3–δ solid solutions were found to have cubic structure (sp. gr. Pm3m). The unit cell parameters were refined using Rietveld full-profile analysis. Oxygen nonstoichiometry of BaCo1–yYyO3–δ solid solutions with 0.1≤y≤0.4 was measured by means of thermogravimetric technique within the temperature range 298–1373 K in air. Thermal expansion of BaCo1–yYyO3–δ (y=0.0; 0.1; 0.2; 0.3) samples was studied within the temperature range 298–1200 K in air. The projection of isothermal–isobaric phase diagram for the Y–Ba–Co–O system to the compositional triangle of metallic components was presented. - Graphical abstract: A projection of isobaric isothermal phase diagram of the Y–Ba–Co–O system to the metallic components

  17. Shelf life of case-ready beef steaks (Semitendinosus muscle) stored in oxygen-depleted master bag system with oxygen scavengers and CO2/N2 modified atmosphere packaging.

    PubMed

    Limbo, S; Uboldi, E; Adobati, A; Iametti, S; Bonomi, F; Mascheroni, E; Santagostino, S; Powers, T H; Franzetti, L; Piergiovanni, L

    2013-03-01

    This study aims to evaluate the stability of beef from Semitendinosus muscle packaged in oxygen permeable wrapped-tray units and stored in a master bag system, with and without oxygen scavengers. Changes in the atmosphere composition, microbiological indexes, myoglobin forms and color parameters were monitored during the storage in master bag, blooming and display life. The presence of scavengers reduced rapidly the oxygen concentration and maintained it at values not detectable instrumentally. Within few days of storage in master bags, the resolution of the transient discoloration was completed and the meat quality was maintained over the anoxic storage. After the removal from master bags meat bloomed completely reaching OxyMb level and Chroma values higher than those on fresh meat at t(0). During 48 h of display life at 4 °C, quality attributes had a decay slower than samples stored traditionally in air. Without scavengers the oxygen caused the irreversible discoloration within 7 days, due to the formation of metmyoglobin on the surface.

  18. 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…

  19. An evaluation of oxygen/hydrogen propulsion systems for the Space Station

    NASA Technical Reports Server (NTRS)

    Klemetson, R. W.; Garrison, P. W.; Hannum, N. P.

    1985-01-01

    Conceptual designs for O2/H2 chemical and resistojet propulsion systems for the Space Station was developed and evaluated. The evolution of propulsion requirements was considered as the Space Station configuration and its utilization as a space transportation node change over the first decade of operation. The characteristics of candidate O2/H2 auxiliary propulsion systems are determined, and opportunities for integration with the OTV tank farm and the Space Station life support, power and thermal control subsystems are investigated. OTV tank farm boiloff can provide a major portion of the growth station impulse requirements and CO2 from the life support system can be a significant propellant resource, provided it is not denied by closure of that subsystem. Waste heat from the thermal control system is sufficient for many propellant conditioning requirements. It is concluded that the optimum level of subsystem integration must be based on higher level Space Station studies.

  20. An evaluation of oxygen-hydrogen propulsion systems for the Space Station

    NASA Technical Reports Server (NTRS)

    Klemetson, R. W.; Garrison, P. W.; Hannum, N. P.

    1985-01-01

    Conceptual designs for O2/H2 chemical and resistojet propulsion systems for the space station was developed and evaluated. The evolution of propulsion requirements was considered as the space station configuration and its utilization as a space transportation node change over the first decade of operation. The characteristics of candidate O2/H2 auxiliary propulsion systems are determined, and opportunities for integration with the OTV tank farm and the space station life support, power and thermal control subsystems are investigated. OTV tank farm boiloff can provide a major portion of the growth station impulse requirements and CO2 from the life support system can be a significant propellant resource, provided it is not denied by closure of that subsystem. Waste heat from the thermal control system is sufficient for many propellant conditioning requirements. It is concluded that the optimum level of subsystem integration must be based on higher level space station studies.

  1. Design considerations for a 10-kW integrated hydrogen-oxygen regenerative fuel cell system

    NASA Astrophysics Data System (ADS)

    Hoberecht, M. A.; Miller, T. B.; Rieker, L. L.; Gonzalez-Sanabria, O. D.

    Integration of an alkaline fuel cell subsystem with an alkaline electrolysis subsystem to form a regenerative fuel cell (RFC) system for low earth orbit (LEO) applications characterized by relatively high overall round trip electrical efficiency, long life, and high reliability is possible with present state of the art technology. A hypothetical 10 kW system computer modeled and studied based on data from ongoing contractual efforts in both the alkaline fuel cell and alkaline water electrolysis areas. The alkaline fuel cell technology is under development utilizing advanced cell components and standard Shuttle Orbiter system hardware. The alkaline electrolysis technology uses a static water vapor feed technique and scaled up cell hardware is developed. The computer aided study of the performance, operating, and design parameters of the hypothetical system is addressed.

  2. Design considerations for a 10-kW integrated hydrogen-oxygen regenerative fuel cell system

    NASA Technical Reports Server (NTRS)

    Hoberecht, M. A.; Miller, T. B.; Rieker, L. L.; Gonzalez-Sanabria, O. D.

    1984-01-01

    Integration of an alkaline fuel cell subsystem with an alkaline electrolysis subsystem to form a regenerative fuel cell (RFC) system for low earth orbit (LEO) applications characterized by relatively high overall round trip electrical efficiency, long life, and high reliability is possible with present state of the art technology. A hypothetical 10 kW system computer modeled and studied based on data from ongoing contractual efforts in both the alkaline fuel cell and alkaline water electrolysis areas. The alkaline fuel cell technology is under development utilizing advanced cell components and standard Shuttle Orbiter system hardware. The alkaline electrolysis technology uses a static water vapor feed technique and scaled up cell hardware is developed. The computer aided study of the performance, operating, and design parameters of the hypothetical system is addressed.

  3. Design and demonstration of a system for the deposition of atomic-oxygen durable coatings for reflective solar dynamic power system concentrators

    NASA Technical Reports Server (NTRS)

    Mcclure, Donald J.

    1988-01-01

    A system for the vacuum deposition of atomic-oxygen durable coatings for reflective solar dynamic power systems (SDPS) concentrators was designed and demonstrated. The design issues pertinent to SDPS were developed by the Government Aerospace Systems Division of the Harris Corporation and are described in NASA-CR-179489. Both design and demonstration phases have been completed. At the time of this report the deposition system was ready for coating of facets for SDPS concentrators. The materials issue relevant to the coating work were not entirely resolved. These issues can only be resolved when substrates which are comparable to those which will be used in flight hardware are available. The substrates available during the contract period were deficient in the areas of surface roughness and contamination. These issues are discussed more thoroughly in the body of the report.

  4. Color analysis method for estimating the oxygen saturation of hemoglobin using an image-input and processing system.

    PubMed

    Hashimoto, M; Hata, R; Isomoto, A; Tyuma, I; Fukuda, M

    1987-04-01

    A color analysis method which enables both qualitative and quantitative analyses of an object's color was developed. The method uses a color image-input and processing system composed of a 3-tube video camera and a digital image analyzer, which quantizes a color image into values of red, green, and blue brightness, then processes these values. We introduced a spectrophotometric principle by the Beer-Lambert law, and were able to establish a color model to analyze an object's color. In the coordinate space based on our color model, the hue of the object's color is represented by the direction from the origin, and the density by the distance from the origin. This new method was used to analyze the colors of hemoglobin solutions at various oxygen saturations and concentrations. The results agreed with the known conditions, indicating the validity of the model and its usefulness for quantitative as well as qualitative analyses of color.

  5. Materials selection for long life in low earth orbit - A critical evaluation of atomic oxygen testing with thermal atom systems

    NASA Technical Reports Server (NTRS)

    Koontz, S. L.; Albyn, K.; Leger, L.

    1990-01-01

    The use of thermal atom test methods as a materials selection and screening technique for low-earth orbit (LEO) spacecraft is critically evaluated. The chemistry and physics of thermal atom environments are compared with the LEO environment. The relative reactivities of a number of materials determined in thermal atom environments are compared with those observed in LEO and in high-quality LEO simulations. Reaction efficiencies (cu cm/atom) measured in a new type of thermal atom apparatus are one-thousandth to one ten-thousandth those observed in LEO, and many materials showing nearly identical reactivities in LEO show relative reactivities differing by as much as a factor of eight in thermal atom systems. A simple phenomenological kinetic model for the reaction of oxygen atoms with organic materials can be used to explain the differences in reactivity in different environments. Certain speciic thermal atom test environments can be used as reliable materials screening tools.

  6. Novel use of the AngioVac® system to remove thrombus during simultaneous extracorporeal membrane oxygenation life support.

    PubMed

    Griffith, Kevin E; Jenkins, Eric; Copenhaver, William; Williams, David M

    2016-03-01

    Extracorporeal membrane oxygenation (ECMO) was introduced to clinical medicine over 40 years ago. While initially used as a treatment for acute respiratory failure in infants, the use of ECMO has grown to include respiratory and circulatory failure in both children and adults, cardiogenic shock, pulmonary embolism, sepsis, trauma, malignancy, pulmonary hemorrhage and as a treatment for hypothermic drowning.(1) Recent technological improvements in ECMO circuitry make it possible to minimize anticoagulation of the ECMO patient, decreasing the incidence of bleeding. Thrombus deposition within the ECMO circuit can be a life-threating complication. ECMO circuit thrombus can be contained in the circuit, adherent to cannula and deposited within the patient. The ability to remove thrombus while the patient remains on ECMO support could be a life-saving measure for some patients. The present case report outlines use of the AngioVac(®) thrombus removal system in concert with ECMO to remove a large thrombus adherent to an ECMO cannula.

  7. Cratos: A Simple Low Power Excavation and Hauling System for Lunar Oxygen Production and General Excavation Tasks

    NASA Technical Reports Server (NTRS)

    Caruso, John J.; Greer, Lawrence C.; John, Wentworth T.; Spina, Dan C.; Krasowski, Mike J.; Abel, Phillip B.; Prokop, Norman F.; Flatico, Joseph M.; Sacksteder, Kurt R.

    2007-01-01

    The development of a robust excavating and hauling system for lunar and planetary excavation is critical to the NASA mission to the Moon and Mars. Cratos was developed as a low center of gravity, small (.75m x .75m x 0.3m), low power tracked test vehicle. The vehicle was modified to excavate and haul because it demonstrated good performance capabilities in a laboratory and field testing. Tested on loose sand in the SLOPE facility, the vehicle was able to pick up, carry, and dump sand, allowing it to accomplish the standard requirements delivery of material to a lunar oxygen production site. Cratos can pick up and deliver raw material to a production plant, as well as deliver spent tailings to a disposal site. The vehicle can complete many other In-Situ Resource Utilization (ISRU) excavation chores and in conjunction with another vehicle or with additional attachments may be able to accomplish all needed ISRU tasks.

  8. Practical use of chemical probes for reactive oxygen species produced in biological systems by γ-irradiation

    NASA Astrophysics Data System (ADS)

    Lee, Min Hee; Moon, Yu Ran; Chung, Byung Yeoup; Kim, Jae-Sung; Lee, Kang-Soo; Cho, Jae-Young; Kim, Jin-Hong

    2009-05-01

    Application of chemical probes, for detection of reactive oxygen species (ROS), was tested during γ-irradiation. The ethanol/α-(4-pyridyl-1-oxide)- N- tert-butylnitrone (4-POBN) and 3,3'-diaminobenzidine (DAB) were structurally stable enough to detect rad OH and H 2O 2, increasingly generated by γ-irradiation up to 1000 Gy. Interestingly, the production rate of H 2O 2, but not rad OH, during γ-irradiation, was significantly different between in vitro systems of lettuce and spinach. These results suggest that 4-POBN and DAB could be utilized as a semi-quantitative probe to quantify rad OH and H 2O 2, produced by γ-irradiation up to 1000 Gy.

  9. Determination of oxygen saturation of the optic nerve head and overlying artery and vein using a snapshot multi-spectral imaging system

    NASA Astrophysics Data System (ADS)

    Khoobehi, Bahram; Eaton, Alexander; Wafapoor, Hussein; Fournier, Paul; Firn, Kim; Peters, Matt; Rodebeck, Ellie; Templet, Brian

    2012-03-01

    We have developed a snapshot optical imaging system capable of taking multiple images simultaneously and sending them to a CCD detector. Using an innovative lens array design, the beam obtained from the fundus camera is segmented into several different images passed through several different bandpass filters. Each bandpass filter defines a unique spectral region of imaging. The images are taken simultaneously into a large silicone chip with a dynamic range of 16 bits (highly sensitive) and are integrated with a single optical connection to a digital fundus camera. Our algorithm maps blood oxygen saturation of the retina using several wavelengths. These wavelengths are capable of approximating the whole hemoglobin spectrum and have been found from a previously developed hyperspectral algorithm. They include four isosbestic points (522, 548, 569, and 586 nm) and three oxygen-sensitive points (542, 560, and 586 nm) where the difference between fully oxygenated and deoxygenated blood is at a maximum. Using MatLab code, color maps of oxygen saturation are produced. The average value taken from all vein areas was 60.53%, assuming that the artery oxygen saturation value is 98%. Oxygen saturation of the tissue was 75.78%. Oxygen saturations of the temporal/inferior/nasal veins ranged from 61.86% to 63.37%; the superior vein was significantly lower (54.19%). Tissue oxygen saturations in different quadrants of the eye ranged from 74.17% to 76.74%. Our algorithm has been developed for measuring oxygen saturation of the retina clinically. This was done for one subject only; further work can extend the measurements to different pigments.

  10. Elements of a decision support system for real-time management ofdissolved oxygen in the San Joaquin River deep water ship channel

    SciTech Connect

    Quinn, N.W.T.; Jacobs, Karl; Chen, Carl W.; Stringfellow, WilliamT.

    2004-07-15

    A decision support system (DSS) has been designed and will be implemented over the next three years to assist in the control and management of episodes of low dissolved oxygen (DO) in a Deep Water Ship Channel (DWSC), located near Stockton, California. The DSS integrates three information technology functions. The first part is the collection and management of data on flow, pollution loads and water quality. The second part is the simulation model which can forecast the dissolved oxygen sag in the DWSC and determine management actions necessary to improve dissolved oxygen concentrations. The third part is the graphical user interface, which facilitates the computer simulations and posting of the forecasted dissolved oxygen and remedial measures to a stakeholder group for implementations.

  11. Design considerations for a 10-KW integrated hydrogen-oxygen regenerative fuel cell system

    SciTech Connect

    Hoberecht, M.A.; Gonzalez-Sanabria, O.D.; Miller, T.B.; Rieker, L.L.

    1984-08-01

    Integration of an alkaline fuel cell subsystem with an alkaline electrolysis subsystem to form a regenerative fuel cell (RFC) system for low-earth-orbit (LEO) applications characterized by relatively high overall round-trip electrical efficiency, long life, and high reliability is possible with present state-of-the-art technology. A hypothetical 10-kW system is being computer modeled and studied based on data from ongoing contractual efforts in both the alkaline fuel cell and alkaline water electrolysis areas. The alkaline fuel cell technology is being developed under an NASA-LeRC program with United Technologies Corporation (UTC), utilizing advanced cell components and standard Shuttle-Orbiter system hardware. The alkaline electrolysis technology is that of Life Systems, Inc. (LSI), which uses a static water vapor feed technique and scaled-up cell hardware being developed under an NASA-LeRC program. This paper addresses the computeraided study of the performance, operating, and design parameters of the hypothetical system.

  12. Component and System Sensitivity Considerations for Design of a Lunar ISRU Oxygen Production Plant

    NASA Technical Reports Server (NTRS)

    Linne, Diane L.; Gokoglu, Suleyman; Hegde, Uday G.; Balasubramaniam, Ramaswamy; Santiago-Maldonado, Edgardo

    2009-01-01

    Component and system sensitivities of some design parameters of ISRU system components are analyzed. The differences between terrestrial and lunar excavation are discussed, and a qualitative comparison of large and small excavators is started. The effect of excavator size on the size of the ISRU plant's regolith hoppers is presented. Optimum operating conditions of both hydrogen and carbothermal reduction reactors are explored using recently developed analytical models. Design parameters such as batch size, conversion fraction, and maximum particle size are considered for a hydrogen reduction reactor while batch size, conversion fraction, number of melt zones, and methane flow rate are considered for a carbothermal reduction reactor. For both reactor types the effect of reactor operation on system energy and regolith delivery requirements is presented.

  13. Hydrogen from Water in a Novel Recombinant Oxygen-Tolerant Cyanobacterial System (Presentation)

    SciTech Connect

    Xu, Q.; Smith, H. O.; Maness, P.-C.

    2007-05-01

    The objective of this report is to develop an O{sub 2}-tolerant cyanobacterial system for continuous light-driven H{sub 2} production from water. The overall goal is to produce a cyanobacterial recombinant to produce H{sub 2} continuously.

  14. 14 CFR Special Federal Aviation... - Rules for use of portable oxygen concentrator systems on board aircraft

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... concentrator systems on board aircraft Federal Special Federal Aviation Regulation 106 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR... OPERATIONS Pt. 121, SFAR No. 106 Special Federal Aviation Regulation 106—Rules for use of portable...

  15. 14 CFR Special Federal Aviation... - Rules for use of portable oxygen concentrator systems on board aircraft

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... concentrator systems on board aircraft Federal Special Federal Aviation Regulation No. 106 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND... SUPPLEMENTAL OPERATIONS Pt. 121, SFAR No. 106 Special Federal Aviation Regulation No. 106—Rules for use...

  16. 14 CFR Special Federal Aviation... - Rules for use of portable oxygen concentrator systems on board aircraft

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... concentrator systems on board aircraft Federal Special Federal Aviation Regulation No. 106 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND... SUPPLEMENTAL OPERATIONS Pt. 121, SFAR No. 106 Special Federal Aviation Regulation No. 106—Rules for use...

  17. 14 CFR Special Federal Aviation... - Rules for use of portable oxygen concentrator systems on board aircraft

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... concentrator systems on board aircraft Federal Special Federal Aviation Regulation 106 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR... OPERATIONS Pt. 121, SFAR No. 106 Special Federal Aviation Regulation 106—Rules for use of portable...

  18. 14 CFR Special Federal Aviation... - Rules for use of portable oxygen concentrator systems on board aircraft

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... concentrator systems on board aircraft Federal Special Federal Aviation Regulation 106 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR... OPERATIONS Pt. 121, SFAR No. 106 Special Federal Aviation Regulation 106—Rules for use of portable...

  19. Simultaneous Monitoring of Vascular Oxygenation and Tissue Oxygen Tension of Breast Tumors under Hyperbaric Oxygen Exposure

    DTIC Science & Technology

    2006-04-01

    FOXY system, on various rat breast tumor size (months 14- 30). Instead of single-channel NIRS, steady-state diffuse reflectance spectroscopy (SSDRS...combination of normobaric and hyperbaric oxygen interventions) simultaneously monitored by steady-state diffuse reflectance spectroscopy (SSDRS) and...simultaneously by steady-state diffuse reflectance spectroscopy (SSDRS) and FOXY oxygen sensor in response to normobaric and hyperbaric oxygen

  20. Uncoupling High Light Responses from Singlet Oxygen Retrograde Signaling and Spatial-Temporal Systemic Acquired Acclimation1[OPEN

    PubMed Central

    Gordon, Matthew; Havaux, Michel; Albrecht-Borth, Verónica

    2016-01-01

    Distinct ROS signaling pathways initiated by singlet oxygen (1O2) or superoxide and hydrogen peroxide have been attributed to either cell death or acclimation, respectively. Recent studies have revealed that more complex antagonistic and synergistic relationships exist within and between these pathways. As specific chloroplastic ROS signals are difficult to study, rapid systemic signaling experiments using localized high light (HL) stress or ROS treatments were used in this study to uncouple signals required for direct HL and ROS perception and distal systemic acquired acclimation (SAA). A qPCR approach was chosen to determine local perception and distal signal reception. Analysis of a thylakoidal ascorbate peroxidase mutant (tapx), the 1O2-retrograde signaling double mutant (ex1/ex2), and an apoplastic signaling double mutant (rbohD/F) revealed that tAPX and EXECUTER 1 are required for both HL and systemic acclimation stress perception. Apoplastic membrane-localized RBOHs were required for systemic spread of the signal but not for local signal induction in directly stressed tissues. Endogenous ROS treatments revealed a very strong systemic response induced by a localized 1 h induction of 1O2 using the conditional flu mutant. A qPCR time course of 1O2 induced systemic marker genes in directly and indirectly connected leaves revealed a direct vascular connection component of both immediate and longer term SAA signaling responses. These results reveal the importance of an EXECUTER-dependent 1O2 retrograde signal for both local and long distance RBOH-dependent acclimation signaling that is distinct from other HL signaling pathways, and that direct vascular connections have a role in spatial-temporal SAA induction. PMID:27288360

  1. A Microperfusion and In-Bore Oxygenator System Designed for Magnetic Resonance Microscopy Studies on Living Tissue Explants

    PubMed Central

    Flint, Jeremy J.; Menon, Kannan; Hansen, Brian; Forder, John; Blackband, Stephen J.

    2015-01-01

    Spectrometers now offer the field strengths necessary to visualize mammalian cells but were not designed to accommodate imaging of live tissues. As such, spectrometers pose significant challenges—the most evident of which are spatial limitations—to conducting experiments in living tissue. This limitation becomes problematic upon trying to employ commercial perfusion equipment which is bulky and—being designed almost exclusively for light microscopy or electrophysiology studies—seldom includes MR-compatibility as a design criterion. To overcome problems exclusive to ultra-high magnetic field environments with limited spatial access, we have designed microperfusion and in-bore oxygenation systems capable of interfacing with Bruker’s series of micro surface-coils. These devices are designed for supporting cellular resolution imaging in MR studies of excised, living tissue. The combined system allows for precise control of both dissolved gas and pH levels in the perfusate thus demonstrating applicability for a wide range of tissue types. Its compactness, linear architecture, and MR-compatible material content are key design features intended to provide a versatile hardware interface compatible with any NMR spectrometer. Such attributes will ensure the microperfusion rig’s continued utility as it may be used with a multitude of contemporary NMR systems in addition to those which are currently in development. PMID:26666980

  2. Temporal-Spatial Interaction between Reactive Oxygen Species and Abscisic Acid Regulates Rapid Systemic Acclimation in Plants[W][OPEN

    PubMed Central

    Suzuki, Nobuhiro; Miller, Gad; Salazar, Carolina; Mondal, Hossain A.; Shulaev, Elena; Cortes, Diego F.; Shuman, Joel L.; Luo, Xiaozhong; Shah, Jyoti; Schlauch, Karen; Shulaev, Vladimir; Mittler, Ron

    2013-01-01

    Being sessile organisms, plants evolved sophisticated acclimation mechanisms to cope with abiotic challenges in their environment. These are activated at the initial site of exposure to stress, as well as in systemic tissues that have not been subjected to stress (termed systemic acquired acclimation [SAA]). Although SAA is thought to play a key role in plant survival during stress, little is known about the signaling mechanisms underlying it. Here, we report that SAA in plants requires at least two different signals: an autopropagating wave of reactive oxygen species (ROS) that rapidly spreads from the initial site of exposure to the entire plant and a stress-specific signal that conveys abiotic stress specificity. We further demonstrate that SAA is stress specific and that a temporal–spatial interaction between ROS and abscisic acid regulates rapid SAA to heat stress in plants. In addition, we demonstrate that the rapid ROS signal is associated with the propagation of electric signals in Arabidopsis thaliana. Our findings unravel some of the basic signaling mechanisms underlying SAA in plants and reveal that signaling events and transcriptome and metabolome reprogramming of systemic tissues in response to abiotic stress occur at a much faster rate than previously envisioned. PMID:24038652

  3. Removal of chemical oxygen demand and dissolved nutrients by a sunken lawn infiltration system during intermittent storm events.

    PubMed

    Hou, Lizhu; Yang, Huan; Li, Ming

    2014-01-01

    Urban surface water runoff typically contains high but varying amounts of organic matter and nutrients that require removal before reuse. Infiltration systems such as sunken lawns can improve water quality. However, there is currently insufficient information describing the treatment efficiency of lawn-based infiltration systems. In this study, novel sunken lawn infiltration systems (SLISs) were designed and their pollutant removal effectiveness was assessed. The results revealed that SLISs with Poa pratensis and Lolium perenne effectively removed most chemical oxygen demand (CODCr) and dissolved nutrients. Average CODCr, total nitrogen (TN), ammonium-nitrogen (NH4(+)-N) and total phosphorus (TP) concentrations were reduced by 78.93, 66.64, 71.86 and 75.83%, respectively, and the corresponding effluent concentrations met the standard for urban miscellaneous water consumption in China. The NH4(+)-N in the synthetic runoff was shown to be removed by adsorption during the stormwater dosing and nitrification during subsequent dry days, as well as through uptake by plants. Phosphorus was mainly removed by adsorption and chemical precipitation. The NH4(+)-N and phosphorus Langmuir isotherm model fitted the clay loam soil adsorption process better than the Freundlich model. Overall, these results indicate that an SLIS provides an alternative means of removing runoff pollutants owing to its efficiency, easy operation and maintenance.

  4. A Microperfusion and In-Bore Oxygenator System Designed for Magnetic Resonance Microscopy Studies on Living Tissue Explants

    NASA Astrophysics Data System (ADS)

    Flint, Jeremy J.; Menon, Kannan; Hansen, Brian; Forder, John; Blackband, Stephen J.

    2015-12-01

    Spectrometers now offer the field strengths necessary to visualize mammalian cells but were not designed to accommodate imaging of live tissues. As such, spectrometers pose significant challenges—the most evident of which are spatial limitations—to conducting experiments in living tissue. This limitation becomes problematic upon trying to employ commercial perfusion equipment which is bulky and—being designed almost exclusively for light microscopy or electrophysiology studies—seldom includes MR-compatibility as a design criterion. To overcome problems exclusive to ultra-high magnetic field environments with limited spatial access, we have designed microperfusion and in-bore oxygenation systems capable of interfacing with Bruker’s series of micro surface-coils. These devices are designed for supporting cellular resolution imaging in MR studies of excised, living tissue. The combined system allows for precise control of both dissolved gas and pH levels in the perfusate thus demonstrating applicability for a wide range of tissue types. Its compactness, linear architecture, and MR-compatible material content are key design features intended to provide a versatile hardware interface compatible with any NMR spectrometer. Such attributes will ensure the microperfusion rig’s continued utility as it may be used with a multitude of contemporary NMR systems in addition to those which are currently in development.

  5. Development of bovine embryos cultured in CR1aa and IVD101 media using different oxygen tensions and culture systems.

    PubMed

    Somfai, Tamás; Inaba, Yasushi; Aikawa, Yoshio; Ohtake, Masaki; Kobayashi, Shuji; Konishi, Kazuyuki; Nagai, Takashi; Imai, Kei

    2010-12-01

    The aim of the present study was to optimise the culture conditions for the in vitro production of bovine embryos. The development of in vitro fertilised bovine oocytes in CR1aa supplemented with 5% calf serum and IVD101 culture media were compared using traditional microdrops and Well of the Well (WOW) culture systems either under 5% or 20% oxygen tension. After 7 days of culture, a significantly higher blastocyst formation rate was obtained for embryos cultured in CR1aa medium compared to those cultured in IVD101, irrespective of O2 tensions and culture systems. The blastocyst formation in IVD101 was suppressed under 20% O2 compared to 5% O2 . Despite their similar total cell numbers, higher rates of inner cell mass (ICM) cells were observed in blastocysts developed in IVD101 medium than in those developed in CR1aa, irrespective of O2 tensions. There was no significant difference in blastocyst formation, total, ICM and trophectoderm (TE) cell numbers between embryos obtained by microdrop and WOW culture systems irrespective of the culture media and O2 tensions used. In conclusion, CR1aa resulted in higher blastocyst formation rates irrespective of O2 tension, whereas IVD101 supported blastocyst formation only under low O2 levels but enhanced the proliferation of ICM cells.

  6. Transitioning Model Potentials to Real Systems. II. Application to Molecular Oxygen

    DTIC Science & Technology

    2000-09-01

    monatomic liquid. This technique was used to obtain interaction potentials of the Lennard - Jones form that accurately describe argon over its entire...a modified Lennard - Jones potential. Simulations using the resulting optimal set of potential parameters of this system predict densities that are...interaction sites centered at the atomic nuclei. The intermolecular interaction is the sum of all site-site interactions described by a modified Lennard

  7. An improved bifunctional oxygen (air) electrode for reversible alkaline fuel cell systems and for rechargeable metal-air batteries

    NASA Astrophysics Data System (ADS)

    Kordesch, K.; Steininger, K.-H.; Tomantschger, K.

    1988-10-01

    Electrodes with a nickel layer of dual pore structure on the electrolyte side and a PTFE-bonded carbon layer on the oxygen (air) side are discussed, with application to space energy storage. During the electrolyis stage, the oxygen fills the large pores of the porous Ni structure with gas. During the discharge cycle, the iron/air or zinc/air cell of the carbon layer operates as a regular oxygen electrode.

  8. Ex Vivo Machine Perfusion in CTA with a Novel Oxygen Carrier System to Enhance Graft Preservation and Immunologic Outcomes

    DTIC Science & Technology

    2014-10-01

    combination with a newly developed hemoglobin based oxygen carrier (HBOC) solution under subnormothermic (21°C) conditions as a way to enhance organ...static preservation, hemoglobin oxygen carrier solutions, vascularized composite allotransplants, ischemia/reperfusion, superior epigastric artery...Assist Liver Device (OALD) (Figure 8) and the VIR-1 solution, which contains a hemoglobin -based oxygen carrier and BMPS mixed 1:3 ratio, respectively

  9. Reactive oxygen system plays an important role in shrimp Litopenaeus vannamei defense against Vibrio parahaemolyticus and WSSV infection.

    PubMed

    Ji, Pei-Feng; Yao, Cui-Luan; Wang, Zhi-Yong

    2011-08-29

    The present study investigated the in vivo hemocytic and hepatopancreatic response to Vibrio parahaemolyticus and white spot syndrome virus (WSSV) injection in shrimp Litopenaeus vannamei. The proliferation of bacteria and virus in shrimp, animal mortality, total hemocyte counts (THCs), phenoloxidase (PO) activity, respiratory burst, and gene expression of immune factors associated with immune recognition (lectin), prophenoloxidase (proPO) activation, and the anti-microorganism (lysozyme) and active oxygen defense response (including respiratory burst, cytosolic manganese superoxide dismutase [C-MnSOD], and catalase [CAT]) were quantified. Shrimp death rate increased significantly and was time-dependent after V. parahaemolyticus or WSSV injection. The production of superoxide anion, and the gene expression including lectin in hemocytes, proPO in the hepatopancreas, lysozyme, C-MnSOD and CAT could be induced by injection with V parahaemolyticus and WSSV. The highest value of lysozyme was in the hemocytes with 66.59 times (at 3 h) greater expression than in the control group after WSSV injection and 3.69 times (24 h) greater than in the control group after V parahaemolyticus injection. In the hepatopancreas, CAT expression showed a significant increase, with up to 16 times greater expression than in the control group at 6 h postinjection with WSSV and 7.02 times greater expression than in the control group at 48 h postinjection with V parahaemolyticus (p < 0.05). However, significant decreases in PO activity and proPO transcripts in hemocytes and lectin transcripts in the hepatopancreas were detected after V parahaemolyticus and WSSV injection (p < 0.05). The results suggest that lysozyme, the antioxidase system, and reactive oxygen species might play a crucial role in shrimp defense against bacterial and viral infection.

  10. Oxygen safety

    MedlinePlus

    ... with electric motors Electric baseboard or space heaters Wood stoves, fireplaces, candles Electric blankets Hairdryers, electric razors, ... Therapy.aspx . Accessed February 9, 2016. National Fire Protection Association. Medical oxygen. Updated July 2013. www.nfpa. ...

  11. Regenerative Hydrogen-oxygen Fuel Cell-electrolyzer Systems for Orbital Energy Storage

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W.

    1984-01-01

    Fuel cells have found application in space since Gemini. Over the years technology advances have been factored into the mainstream hardware programs. Performance levels and service lives have been gradually improving. More recently, the storage application for fuel cell-electrolyzer combinations are receiving considerable emphasis. The regenerative system application described here is part of a NASA Fuel Cell Program which was developed to advance the fuel cell and electrolyzer technology required to satisfy the identified power generation and energy storage need of the Agency for space transportation and orbital applications to the year 2000.

  12. Critical review of carbon monoxide pressure measurements in the uranium carbon oxygen ternary system

    NASA Astrophysics Data System (ADS)

    Gossé, S.; Guéneau, C.; Chatillon, C.; Chatain, S.

    2006-06-01

    For high temperature reactors (HTR), the high level of fuel operating temperature in normal and accidental conditions requires to predict the possible chemical interactions between the fuel components. Among the concerns of the TRISO fuel particle thermomechanical behavior, it is necessary to better understand the carbon monoxide formation due to chemical interactions at the UO2 kernel and graphite buffer's interface. In a first step, the thermodynamic properties of the U-C-O system have to be assessed. The experimental data from literature on the equilibrium CO gas pressure measurements in the UO2-UC2-C ternary section of the U-C-O system are critically reviewed. Discrepancies between the different determinations can be explained - (i) by the different gaseous flow regimes in the experiments and - (ii) by the location of the measuring pressure gauge away from the reaction site. Experimental values are corrected - (i) from the gaseous flow type (molecular, transition or viscous) defined by the Knudsen number and - (ii) from the thermomolecular effect due to the temperature gradient inside the experimental vessels. Taking account of the selected and corrected values improves greatly the consistency of the original set of measurements.

  13. Phase equilibria, crystal structure and oxygen content of intermediate phases in the Y-Ba-Co-O system

    NASA Astrophysics Data System (ADS)

    Urusova, A. S.; Cherepanov, V. A.; Aksenova, T. V.; Gavrilova, L. Ya.; Kiselev, E. A.

    2013-06-01

    The phase equilibria in the Y-Ba-Co-O system were systematically studied at 1373 K in air. The intermediate phases formed in the Y-Ba-Co-O system at 1373 K in air were: YBaCo2O5+δ, YBaCo4O7 and BaCo1-yYyO3-δ (0.09≤y≤0.42). It was shown that YBaCo2O5+δ possesses tetragonal structure with the 3ap×3ap×2ap superstructure (sp. gr. P4/mmm). High-temperature X-ray diffraction analysis of the YBaCo2O5+δ in the temperature range from 298 K up to 1073 K under Po2=0.21 аtm has not shown any phase transformations. The value of oxygen content for the YBaCo2O5+δ at room temperature was estimated as 5.40 and at 1323 K it was equal to 5.04. Thermal expansion of sample shows a linear characteristics and the average thermal expansion coefficient (TEC) is about 13.8×10-6, K-1 in the temperature range 298-1273 K. The homogeneity range and crystal structure of the BaCo1-yYyO3-δ (0.09≤y≤0.42) solid solutions were determined by X-ray diffraction of quenched samples. All BaCo1-yYyO3-δ solid solutions were found to have cubic structure (sp. gr. Pm3m). The unit cell parameters were refined using Rietveld full-profile analysis. Oxygen nonstoichiometry of BaCo1-yYyO3-δ solid solutions with 0.1≤y≤0.4 was measured by means of thermogravimetric technique within the temperature range 298-1373 K in air. Thermal expansion of BaCo1-yYyO3-δ (у=0.0; 0.1; 0.2; 0.3) samples was studied within the temperature range 298-1200 K in air. The projection of isothermal-isobaric phase diagram for the Y-Ba-Co-O system to the compositional triangle of metallic components was presented.

  14. Efficacy of oxygen-supplying capacity of Azolla in a controlled life support system

    NASA Astrophysics Data System (ADS)

    Chen, Min; Deng, Sufang; Yang, Youquan; Huang, Yibing; Liu, Chongchu

    2012-02-01

    Azolla shows high growth and propagation rates, strong photosynthetic O2-releasing ability and high nutritional value. It is suitable as a salad vegetable and can be cultured on a multi-layered wet bed. Hence, it possesses potential as a fresh vegetable, and to release O2 and absorb CO2 in a Controlled Ecological Life Support System in space. In this study, we investigated the O2-providing characteristics of Azolla in a closed chamber under manned, controlled conditions to lay a foundation for use of Azolla as a biological component in ground simulation experiments for space applications. A closed test chamber, representing a Controlled Ecological Life Support System including an Azolla wet-culture device, was built to measure the changes in atmospheric O2 and CO2 concentrations inside the chamber in the presence of coexisting Azolla, fish and men. The amount of O2 consumed by fish was 0.0805-0.0831 L kg-1 h-1 and the level of CO2 emission was 0.0705-0.0736 L kg-1 h-1; O2 consumption by the two trial volunteers was 19.71 L h-1 and the volume of respiration-released CO2 was 18.90 L h-1. Under 7000-8000 Lx artificial light and Azolla wet-culture conditions, human and fish respiration and Azolla photosynthesis were complementary, thus the atmospheric O2 and CO2 concentrations inside chamber were maintained in equilibrium. The increase in atmospheric CO2 concentration in the closed chamber enhanced the net photosynthesis efficiency of the Azolla colony. This study showed that Azolla has strong photosynthetic O2-releasing ability, which equilibrates the O2 and CO2 concentrations inside the chamber in favor of human survival and verifies the potential of Azolla for space applications.

  15. Liquid Oxygen Rotating Friction Ignition Testing of Aluminum and Titanium with Monel and Inconel for Rocket Engine Propulsion System Contamination Investigation

    NASA Technical Reports Server (NTRS)

    Peralta, S.; Rosales, Keisa R.; Stoltzfus, Joel M.

    2009-01-01

    Metallic contaminant was found in the liquid oxygen (LOX) pre-valve screen of the shuttle main engine propulsion system on two orbiter vehicles. To investigate the potential for an ignition, NASA Johnson Space Center White Sands Test Facility performed (modified) rotating friction ignition testing in LOX. This testing simulated a contaminant particle in the low-pressure oxygen turbo pump (LPOTP) and the high-pressure oxygen turbo pump (HPOTP) of the shuttle main propulsion system. Monel(R) K-500 and Inconel(R) 718 samples represented the LPOTP and HPOTP materials. Aluminum foil tape and titanium foil represented the contaminant particles. In both the Monel(R) and Inconel(R) material configurations, the aluminum foil tape samples did not ignite after 30 s of rubbing. In contrast, all of the titanium foil samples ignited regardless of the rubbing duration or material configuration. However, the titanium foil ignitions did not propagate to the Monel and Inconel materials.

  16. Resonance Raman study of the oxygenation cycle of optically trapped single red blood cells in a microfluidic system

    NASA Astrophysics Data System (ADS)

    Ramser, Kerstin; Logg, Katarina; Enger, Jonas; Goksor, Mattias; Kall, Mikael; Hanstorp, Dag

    2004-10-01

    The average environmental response of red blood cells (RBCs) is routinely measured in ensemble studies, but in such investigations valuable information on the single cell level is obscured. In order to elucidate this hidden information is is important to enable the selection of single cells with certain properties while subsequent dynamics triggered by environmental stimulation are recorded in real time. It is also desirable to manipulate and control the cells under phsyiological conditions. As shown here, this can be achieved by combining optical tweezers with a confocal Raman set-up equipped with a microfluidic system. A micro-Raman set-up is combined with an optical trap with separate optical paths, lasers and objectives, which enables the acquisition of resonance Raman profils of single RBCs. The microfluidic system, giving full control over the media surrounding the cell, consists of a pattern of channels and reservoirs produced by electron beam lithography and moulded in PDMS. Fresh Hepes buffer or buffer containing sodium dithionite are transported through the channels using electro-osmotic flow, while the direct Raman response of the single optically trapped RBC is registered in another reservoir in the middle of the channel. Thus, it is possible to monitor the oxygenation cycle in a single cell and to study photo-induced chemistry. This experimental set-up has high potential for monitoring the drug response or conformational changes caused by other environmental stimuli for many types of single functional cells since "in vivo" conditions can be created.

  17. Nutrients, oxygen dynamics, stable isotopes and fatty acid concentrations of a freshwater tidal system, Washington, D.C.

    PubMed

    MacAvoy, Stephen E; Ewers, Evan C; Bushaw-Newton, Karen L

    2009-09-01

    The Anacostia River in Washington, D.C., USA is an urban waterway contaminated with PAHs, PCBs, metals and sewage. Although several studies have examined the heavy metal geochemistry within the river, no studies have examined basic biogeochemical processes within the Anacostia river system. This study examines nutrients, bacterial biomarkers, organic material, and carbon, nitrogen and sulfur sources in the system. High biological oxygen demand and low nitrogen (0.33-0.56 mg L(-1)) and phosphorus (0.014-0.021 mg L(-1)) concentrations were observed in three areas of the river. Downstream sites had higher nutrient concentrations and dissolved organic matter (up to 13.7 mg L(-1)). Odd-chain length and branched fatty acids (FAs) in the sediments indicated bacterial sources, but long chain FAs indicative of terrestrial primary production were also abundant in some sediments. Sediment carbon stable isotope analyses showed a mix of autochthonous and allochthonous derived materials, but most carbon was derived from terrestrial sources (-23.3 to -31.7 per thousand). Sediment nitrogen stable isotopes ranged from -5.4 to 5.6 per thousand, showing nitrate uptake by plants and also recycling of nitrogen within the river. Sulfur sources were generally between 3 and -5 per thousand, reflecting local sulfate sources and anaerobic sulfate reduction.

  18. Noninvasive monitoring of cerebral blood oxygenation in ovine superior sagittal sinus with novel multi-wavelength optoacoustic system.

    PubMed

    Petrova, I Y; Petrov, Y Y; Esenaliev, R O; Deyo, D J; Cicenaite, I; Prough, D S

    2009-04-27

    Noninvasive monitoring of cerebral blood oxygenation with an optoacoustic technique offers advantages over current invasive and noninvasive methods. We report the results of in vivo studies in the sheep superior sagittal sinus (SSS), a large central cerebral vein. We changed blood oxygenation by increasing and decreasing the inspired fraction of oxygen (FiO(2)). Optoacoustic measurements from the SSS were performed at wavelengths of 700, 800, and 1064 nm using an optical parametric oscillator as a source of pulsed near-infrared light. Actual oxygenation of SSS blood was measured with a CO-Oximeter in blood samples drawn from the SSS through a small craniotomy. The amplitude of the optoacoustic signal induced in the SSS blood at lambda = 1064 nm closely followed the changes in blood oxygenation, at lambda = 800 nm was almost constant, and at lambda = 700 nm was changing in the opposite direction, all in accordance with the absorption spectra of oxy- and deoxyhemoglobin. The optoacoustically predicted oxygenation correlated well with actual blood oxygenation in sheep SSS (R(2) = 0.965 to 0.990). The accuracy was excellent, with a mean difference of 4.8% to 9.3% and a standard deviation of 2.8% to 4.2%. To the best of our knowledge, this paper reports for the first time accurate measurements of cerebral venous blood oxygenation validated against the "gold standard" CO-Oximetry method.

  19. Analysis of reactive oxygen species generating systems in rat epididymal spermatozoa.

    PubMed

    Vernet, P; Fulton, N; Wallace, C; Aitken, R J

    2001-10-01

    Epididymal sperm maturation culminates in the acquisition of functional competence by testicular spermatozoa. The expression of this functional state is dependent upon a redox-regulated, cAMP-mediated signal transduction cascade that controls the tyrosine phosphorylation status of the spermatozoa during capacitation. Analysis of superoxide anion (O2(-.)) generation by rat epididymal spermatozoa has revealed a two-component process involving electron leakage from the sperm mitochondria at complexes I and II and a plasma membrane NAD(P)H oxidoreductase. Following incubation in a glucose-, lactate-, and pyruvate-free medium (-GLP), O2(-.) generation was suppressed by 86% and 96% in caput and cauda spermatozoa, respectively. The addition of lactate, malate, or succinate to spermatozoa incubated in medium -GLP stimulated O2(-.) generation. This increase could be blocked by rotenone and oligomycin (R/O) in the presence of malate or lactate but not succinate. Stimulation with all three substrates, as well as spontaneous O2(-.) production in +GLP medium, was blocked by the flavoprotein inhibitor, diphenylene iodonium. Diphenylene iodonium, but not R/O, suppressed NAD(P)H-induced lucigenin-dependent chemiluminescence. This NAD(P)H-dependent enzyme resided in the sperm plasma membrane and its activity was regulated by zinc and uncharacterized cytosolic factors. Reverse transcription-polymerase chain reaction analysis indicated that the sperm NAD(P)H oxidoreductase complex is quite distinct from the equivalent leukocyte system.

  20. Influence of expiratory flow-limitation during exercise on systemic oxygen delivery in humans.

    PubMed

    Aliverti, A; Dellacà, R L; Lotti, P; Bertini, S; Duranti, R; Scano, G; Heyman, J; Lo Mauro, A; Pedotti, A; Macklem, P T

    2005-10-01

    To determine the effects of exercise with expiratory flow-limitation (EFL) on systemic O(2) delivery, seven normal subjects performed incremental exercise with and without EFL at approximately 0.8 l s(-1) (imposed by a Starling resistor in the expiratory line) to determine maximal power output under control (W'(max,c)) and EFL (W'(max,e)) conditions. W'(max,e) was 62.5% of W'(max,c), and EFL exercise caused a significant fall in the ventilatory threshold. In a third test, after exercising at W'(max,e) without EFL for 4 min, EFL was imposed; exercise continued for 4 more minutes or until exhaustion. O(2) consumption (V'(O)(2)) was measured breath-by-breath for the last 90 s of control, and for the first 90 s of EFL exercise. Assuming that the arterio-mixed venous O(2) content remained constant immediately after EFL imposition, we used V'(O)(2) as a measure of cardiac output (Q'(c)). Q'(c) was also calculated by the pulse contour method with blood pressure measured continuously by a photo-plethysmographic device. Both sets of data showed a decrease of Q'(c) due to a decrease in stroke volume by 10% (p < 0.001 for V'(O)(2)) with EFL and remained decreased for the full 90 s. Concurrently, arterial O(2) saturation decreased by 5%, abdominal, pleural and alveolar pressures increased, and duty cycle decreased by 43%. We conclude that this combination of events led to a decrease in venous return secondary to high expiratory pressures, and a decreased duty cycle which decreased O(2) delivery to working muscles by approximately 15%.

  1. Technical Update: Johnson Space Center system using a solid electrolytic cell in a remote location to measure oxygen fugacities in CO/CO2 controlled-atmosphere furnaces

    NASA Technical Reports Server (NTRS)

    Jurewicz, A. J. G.; Williams, R. J.; Le, L.; Wagstaff, J.; Lofgren, G.; Lanier, A.; Carter, W.; Roshko, A.

    1993-01-01

    Details are given for the design and application of a (one atmosphere) redox-control system. This system differs from that given in NASA Technical Memorandum 58234 in that it uses a single solid-electrolytic cell in a remote location to measure the oxygen fugacities of multiple CO/CO2 controlled-atmosphere furnaces. This remote measurement extends the range of sample-furnace conditions that can be measured using a solid-electrolytic cell, and cuts costs by extending the life of the sensors and by minimizing the number of sensors in use. The system consists of a reference furnace and an exhaust-gas manifold. The reference furnace is designed according to the redox control system of NASA Technical Memorandum 58234, and any number of CO/CO2 controlled-atmosphere furnaces can be attached to the exhaust-gas manifold. Using the manifold, the exhaust gas from individual CO/CO2 controlled atmosphere furnaces can be diverted through the reference furnace, where a solid-electrolyte cell is used to read the ambient oxygen fugacity. The oxygen fugacity measured in the reference furnace can then be used to calculate the oxygen fugacity in the individual CO/CO2 controlled-atmosphere furnace. A BASIC computer program was developed to expedite this calculation.

  2. Technical Note: Controlled experimental aquarium system for multi-stressor investigation of carbonate chemistry, oxygen saturation, and temperature

    NASA Astrophysics Data System (ADS)

    Bockmon, E. E.; Frieder, C. A.; Navarro, M. O.; White-Kershek, L. A.; Dickson, A. G.

    2013-09-01

    As the field of ocean acidification has grown, researchers have increasingly turned to laboratory experiments to understand the impacts of increased CO2 on marine organisms. However, other changes such as ocean warming and deoxygenation are occurring concurrently with the increasing CO2 concentrations, complicating the understanding of the impacts of anthropogenic changes on organisms. This experimental aquarium design allows for independent regulation of CO2 concentration, O2 levels, and temperature in a controlled environment to study the impacts of multiple stressors. The system has the flexibility for a wide range of treatment chemistry, seawater volumes, and study organisms. Control of the seawater chemistry is achieved by equilibration of a chosen gas mixture with seawater using a Liqui-Cel® membrane contactor. Included as examples, two experiments performed using the system have shown control of CO2 at values between approximately 500 and 1400 μatm and O2 at values from 80 to 240 μmol kg-1. Temperature has been maintained to 0.5 °C or better in the range of 10-17 °C. On a weeklong timescale, the system has achieved variability in pH of less than 0.007 pH units and in oxygen concentration of less than 3.5 μmol kg-1. Longer experiments, over a month in duration, have been completed with control to better than 0.08 pH units and 13 μmol kg-1 O2. The ability to study the impacts of multiple stressors in the laboratory simultaneously, as well as independently, will be an important part of understanding the response of marine organisms to a high-CO2 world.

  3. Dissolved oxygen as a factor influencing nitrogen removal rates in a one-stage system with partial nitritation and Anammox process.

    PubMed

    Cema, G; Płaza, E; Trela, J; Surmacz-Górska, J

    2011-01-01

    A biofilm system with Kaldnes biofilm carrier was used in these studies to cultivate bacteria responsible for both partial nitritation and Anammox processes. Due to co-existence of oxygen and oxygen-free zones within the biofilm depth, both processes can occur in a single reactor. Oxygen that inhibits the Anammox process is consumed in the outer layer of the biofilm and in this way Anammox bacteria are protected from oxygen. The impact of oxygen concentration on nitrogen removal rates was investigated in the pilot plant (2.1 m3), supplied with reject water from the Himmerfjärden Waste Water Treatment Plant. The results of batch tests showed that the highest nitrogen removal rates were obtained for a dissolved oxygen (DO) concentration around 3 g O2 m(-3) At a DO concentration of 4 g O2 m(-3), an increase of nitrite and nitrate nitrogen concentrations in the batch reactor were observed. The average nitrogen removal rate in the pilot plant during a whole operating period oscillated around 1.3 g N m(-2)d(-1) (0.3 +/- 0.1 kg N m(-3)d(-1)) at the average dissolved oxygen concentration of 2.3 g O2 m(-3). The maximum value of a nitrogen removal rate amounted to 1.9 g N m(-2)d(-1) (0.47 kg N m(-3)d(-1)) and was observed for a DO concentration equal to 2.5 g O2 m(-3). It was observed that increase of biofilm thickness during the operational period, had no influence on nitrogen removal rates in the pilot plant.

  4. High Selectivity Oxygen Delignification

    SciTech Connect

    Lucian A. Lucia

    2005-11-15

    Project Objective: The objectives of this project are as follows: (1) Examine the physical and chemical characteristics of a partner mill pre- and post-oxygen delignified pulp and compare them to lab generated oxygen delignified pulps; (2) Apply the chemical selectivity enhancement system to the partner pre-oxygen delignified pulps under mill conditions (with and without any predetermined amounts of carryover) to determine how efficiently viscosity is preserved, how well selectivity is enhanced, if strength is improved, measure any yield differences and/or bleachability differences; and (3) Initiate a mill scale oxygen delignification run using the selectivity enhancement agent, collect the mill data, analyze it, and propose any future plans for implementation.

  5. A microfluidic system enabling Raman measurements of the oxygenation cycle in single optically trapped red blood cells.

    PubMed

    Ramser, Kerstin; Enger, Jonas; Goksör, Mattias; Hanstorp, Dag; Logg, Katarina; Käll, Mikael

    2005-04-01

    Using a lab-on-a-chip approach we demonstrate the possibility of selecting a single cell with certain properties and following its dynamics after an environmental stimulation in real time using Raman spectroscopy. This is accomplished by combining a micro Raman set-up with optical tweezers and a microfluidic system. The latter gives full control over the media surrounding the cell, and it consists of a pattern of channels and reservoirs defined by electron beam lithography that is moulded into rubber silicon (PDMS). Different buffers can be transported through the channels using electro-osmotic flow, while the resonance Raman response of an optically trapped red blood cell (RBC) is simultaneously registered. This makes it possible to monitor the oxygenation cycle of the cell in real time and to investigate effects like photo-induced chemistry caused by the illumination. The experimental set-up has high potential for in vivo monitoring of cellular drug response using a variety of spectroscopic probes.

  6. Quantum dots assisted photocatalysis for the chemiluminometric determination of chemical oxygen demand using a single interface flow system.

    PubMed

    Silvestre, Cristina I C; Frigerio, Christian; Santos, João L M; Lima, José L F C

    2011-08-12

    A novel flow method for the determination of chemical oxygen demand (COD) is proposed in this work. It relies on the combination of a fully automated single interface flow system, an on-line UV photocatalytic unit and quantum dot (QD) nanotechnology. The developed approach takes advantage of CdTe nanocrystals capacity to generate strong oxidizing species upon irradiation with UV light, which fostered a fast catalytic degradation of the organic compounds. Luminol was used as a chemiluminescence (CL) probe for indirect COD assessment, since it is easily oxidized by the QD generated species yielding a strong CL emission that is quenched in the presence of the organic matter. The proposed methodology allowed the determination of COD concentrations between 1 and 35 mg L(-1), with good precision (R.S.D.<1.1%, n=3) and a sampling frequency of about 33 h(-1). The procedure was applied to the determination of COD in wastewater certified reference materials and the obtained results showed an excellent agreement with the certified values.

  7. Type VI secretion system contributes to Enterohemorrhagic Escherichia coli virulence by secreting catalase against host reactive oxygen species (ROS)

    PubMed Central

    Ni, Jinjing; Wen, Donghua; Li, Jun; Xiao, Haihan; He, Ping; Ou, Hong-yu; Tao, Jing; Lu, Jie; Wu, Wenjuan

    2017-01-01

    Enterohemorrhagic Escherichia coli (EHEC) is one major type of contagious and foodborne pathogens. The type VI secretion system (T6SS) has been shown to be involved in the bacterial pathogenicity and bacteria-bacteria competition. Here, we show that EHEC could secrete a novel effector KatN, a Mn-containing catalase, in a T6SS-dependent manner. Expression of katN is promoted by RpoS and OxyR and repressed by H-NS, and katN contributes to bacterial growth under oxidative stress in vitro. KatN could be secreted into host cell cytosol after EHEC is phagocytized by macrophage, which leads to decreased level of intracellular reactive oxygen species (ROS) and facilitates the intramacrophage survival of EHEC. Finally, animal model results show that the deletion mutant of T6SS was attenuated in virulence compared with the wild type strain, while the deletion mutant of katN had comparable virulence to the wild type strain. Taken together, our findings suggest that EHEC could sense oxidative stress in phagosome and decrease the host cell ROS by secreting catalase KatN to facilitate its survival in the host cells. PMID:28288207

  8. Simultaneous Laser-induced Fluorescence of Nitric Oxide and Atomic Oxygen in the Hypersonic Materials Environment Test System Arcjet Facility

    NASA Technical Reports Server (NTRS)

    Johansen, Craig; Lincoln, Daniel; Bathel, Brett; Inman, Jennifer; Danehy, Paul

    2014-01-01

    Simultaneous nitric oxide (NO) and atomic oxygen (O) laser induced fluorescence (LIF) experiments were performed in the Hypersonic Materials Environmental Test System (HYMETS) facility at the NASA Langley Research Center. The data serves as an experimental database for validation for chemical and thermal nonequilibrium models used in hypersonic flows. Measurements were taken over a wide range of stagnation enthalpies (6.7 - 18.5 MJ/kg) using an Earth atmosphere simulant with a composition of 75% N2, 20% O2, and 5% Ar (by volume). These are the first simultaneous measurements of NO and O LIF to be reported in literature for the HYMETS facility. The maximum O LIF mean signal intensity was observed at a stagnation enthalpy of approximately 12 MJ/kg while the maximum NO LIF mean signal intensity was observed at a stagnation enthalpy of 6.7 MJ/kg. Experimental results were compared to simple fluorescence model that assumes equilibrium conditions in the plenum and frozen chemistry in the isentropic nozzle expansion (Mach 5). The equilibrium calculations were performed using CANTERA v2.1.1 with 16 species. The fluorescence model captured the correlation in mean O and NO LIF signal intensities over the entire range of stagnation enthalpies tested. Very weak correlations between single-shot O and NO LIF intensities were observed in the experiments at all of the stagnation enthalpy conditions.

  9. Programmable flow system for automation of oxygen radical absorbance capacity assay using pyrogallol red for estimation of antioxidant reactivity.

    PubMed

    Ramos, Inês I; Gregório, Bruno J R; Barreiros, Luísa; Magalhães, Luís M; Tóth, Ildikó V; Reis, Salette; Lima, José L F C; Segundo, Marcela A

    2016-04-01

    An automated oxygen radical absorbance capacity (ORAC) method based on programmable flow injection analysis was developed for the assessment of antioxidant reactivity. The method relies on real time spectrophotometric monitoring (540 nm) of pyrogallol red (PGR) bleaching mediated by peroxyl radicals in the presence of antioxidant compounds within the first minute of reaction, providing information about their initial reactivity against this type of radicals. The ORAC-PGR assay under programmable flow format affords a strict control of reaction conditions namely reagent mixing, temperature and reaction timing, which are critical parameters for in situ generation of peroxyl radical from 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH). The influence of reagent concentrations and programmable flow conditions on reaction development was studied, with application of 37.5 µM of PGR and 125 mM of AAPH in the flow cell, guaranteeing first order kinetics towards peroxyl radicals and pseudo-zero order towards PGR. Peroxyl-scavenging reactivity of antioxidants, bioactive compounds and phenolic-rich beverages was estimated employing the proposed methodology. Recovery assays using synthetic saliva provided values of 90 ± 5% for reduced glutathione. Detection limit calculated using the standard antioxidant compound Trolox was 8 μM. RSD values were <3.4 and <4.9%, for intra and inter-assay precision, respectively. Compared to previous batch automated ORAC assays, the developed system also accounted for high sampling frequency (29 h(-1)), low operating costs and low generation of waste.

  10. Evaluating the ocean biogeochemical components of Earth system models using atmospheric potential oxygen and ocean color data

    NASA Astrophysics Data System (ADS)

    Nevison, C. D.; Manizza, M.; Keeling, R. F.; Kahru, M.; Bopp, L.; Dunne, J.; Tiputra, J.; Ilyina, T.; Mitchell, B. G.

    2015-01-01

    The observed seasonal cycles in atmospheric potential oxygen (APO) at a range of mid- to high-latitude surface monitoring sites are compared to those inferred from the output of six Earth system models (ESMs) participating in the fifth phase of the Coupled Model Intercomparison Project phase 5 (CMIP5). The simulated air-sea O2 fluxes are translated into APO seasonal cycles using a matrix method that takes into account atmospheric transport model (ATM) uncertainty among 13 different ATMs. Three of the ocean biogeochemistry models tested are able to reproduce the observed APO cycles at most sites, to within the large TransCom3-era ATM uncertainty used here, while the other three generally are not. Net primary production (NPP) and net community production (NCP), as estimated from satellite ocean color data, provide additional constraints, albeit more with respect to the seasonal phasing of ocean model productivity than overall magnitude. The present analysis suggests that, of the tested ocean biogeochemistry models, the community ecosystem model (CESM) and the Geophysical Fluid Dynamics Laboratory (GFDL) ESM2M are best able to capture the observed APO seasonal cycle at both northern and southern hemispheric sites. In most models, discrepancies with observed APO can be attributed to the underestimation of NPP, deep ventilation or both in the northern oceans.

  11. Evaluating the ocean biogeochemical components of earth system models using atmospheric potential oxygen (APO) and ocean color data

    NASA Astrophysics Data System (ADS)

    Nevison, C. D.; Manizza, M.; Keeling, R. F.; Kahru, M.; Bopp, L.; Dunne, J.; Tjiputra, J.; Mitchell, B. G.

    2014-06-01

    The observed seasonal cycles in atmospheric potential oxygen (APO) at a range of mid to high latitude surface monitoring sites are compared to those inferred from the output of 6 Earth System Models participating in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). The simulated air-sea O2 fluxes are translated into APO seasonal cycles using a matrix method that takes into account atmospheric transport model (ATM) uncertainty among 13 different ATMs. Half of the ocean biogeochemistry models tested are able to reproduce the observed APO cycles at most sites, to within the current large ATM uncertainty, while the other half generally are not. Net Primary Production (NPP) and net community production (NCP), as estimated from satellite ocean color data, provide additional constraints, albeit more with respect to the seasonal phasing of ocean model productivity than the overall magnitude. The present analysis suggests that, of the tested ocean biogeochemistry models, CESM and GFDL ESM2M are best able to capture the observed APO seasonal cycle at both Northern and Southern Hemisphere sites. In the northern oceans, the comparison to observed APO suggests that most models tend to underestimate NPP or deep ventilation or both.

  12. Evaluation of ASD systems for electric arc furnace and argon oxygen decarburization refiner baghouse fans. Final report

    SciTech Connect

    1997-11-01

    Adjustable speed drive (ASD) control of the baghouse fans for Electric Arc Furnace (EAF) and Argon Oxygen Decarburization Vessel (AOD) can improve operations, reduce the degree of dust generation, and provide significant energy savings. The purpose of the project was to quantify the benefits, both in energy savings and other process improvements and to demonstrate the methodology of applying adjustable speed drives, to two baghouse fans from a system perspective. The report describes the approach to accomplishing the ASD equipment installation, the test procedure and methodology and provides the test results and economic return. The test results indicated that by using ASDs to control the extraction fan air flow for the EAF and AOD, the following benefits would be achieved on an annual basis: EAF annual energy savings, 267,929 kWh valued at $11,575; EAF dust reduction, overall, 2--3%; EAF dust reduction, during the flatbath period, 35%; and AOD annual energy savings, 1,443,078 kWh valued at $62,341.

  13. Materials selection for long life in LEO: A critical evaluation of atomic oxygen testing with thermal atom systems

    NASA Technical Reports Server (NTRS)

    Koontz, S. L.; Kuminecz, J.; Leger, L.; Nordine, P.

    1988-01-01

    The use of thermal atom test methods as a materials selection and screening technique for low-Earth orbit (LEO) spacecraft is critically evaluated. The chemistry and physics of thermal atom environments are compared with the LEO environment. The relative reactivities of a number of materials determined to be in thermal atom environments are compared to those observed in LEO and in high quality LEO simulations. Reaction efficiencies measured in a new type of thermal atom apparatus are one-hundredth to one-thousandth those observed in LEO, and many materials showing nearly identical reactivities in LEO show relative reactivities differing by as much as a factor of 8 in thermal atom systems. A simple phenomenological kinetic model for the reaction of oxygen atoms with organic materials can be used to explain the differences in reactivity in different environments. Certain specific thermal test environments can be used as reliable materials screening tools. Using thermal atom methods to predict material lifetime in LEO requires direct calibration of the method against LEO data or high quality simulation data for each material.

  14. Profiling iron corrosion coating on iron grains in a zerovalent iron system under the influence of dissolved oxygen.

    PubMed

    Zhang, Tian C; Huang, Yong H

    2006-07-01

    Rapid oxidation of Fe(0) by O(2) occurred when Fe(0) grains were bathed in 0.54 mM FeCl(2) solution saturated with dissolved oxygen (DO), forming a substantial corrosion coating on Fe(0) grains. A sonication method was developed to strip the corrosion coating off the iron grains layer by layer. The transformation of the constituents and the morphology of the corrosion coating along its depth and over reaction time were investigated with composition analysis, X-ray diffraction and scanning electron microscopy. Results indicate that the sonication method could consistently recover >90% iron oxides produced by the Fe(0)-DO redox reaction. Magnetite (Fe(3)O(4)) and lepidocrocite (gamma-FeOOH) were identified as the corrosion products. Initially, lepidocrocite was the preferential product in the presence of DO. As the oxide coating thickened, the inner layer transformed to magnetite, which retained as the only stable corrosion product once DO was depleted. The study confirms the phase transformations between gamma-FeOOH and Fe(3)O(4) within a stratified corrosion coating. The sonication technique exemplifies a new approach for investigating more complicated processes in Fe(0)/oxides/contaminants systems.

  15. Oxygen isotope mapping of the Archean Sturgeon Lake caldera complex and VMS-related hydrothermal system, Northwestern Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Holk, Gregory J.; Taylor, Bruce E.; Galley, Alan G.

    2008-08-01

    The hydrothermal and magmatic evolution of the Sturgeon Lake caldera complex is graphically documented by a regional-scale (525 km2) analysis of oxygen isotopes. Spatial variations in whole-rock oxygen isotope compositions provide a thermal map of the cumulative effects of multiple stages of hydrothermal metasomatism before, during, and after volcanogenic massive sulfide (VMS) mineralization. There is a progressive, upward increase in δ18O from less than 2‰ to greater than 15‰ through a 5-km-thick section above the Biedelman Bay subvolcanic intrusive complex. This isotopic trend makes it clear that at least the earlier phases of this intrusive complex were coeval with the overlying VMS-hosting cauldron succession and provided thermal energy to drive a convective hydrothermal circulation system. The sharp contrast in δ18O values between late stage phases of the Biedelman Bay intrusion and immediate hanging wall strata indicates that the main phase of VMS-related hydrothermal activity took place before late-stage resurgence in the cauldron-related magmatic activity. Mineralogical and isotopic evidence indicates the presence of both syn- and postmineralization hydrothermal activity defined by the presence of widespread semiconformable and more restricted discordant alteration zones that affect the pre- and syncauldron strata. The semiconformable alteration zones formed during early stages of hydrothermal circulation and are defined by widespread silicification and carbonatization in association with relatively high δ18O values. The discordant alteration assemblages, containing Al-silicate minerals with chloritoid and/or Fe-rich carbonate or chlorite, centered on synvolcanic faults represent restricted zones of both seawater inflow and hydrothermal fluid upflow. A rapid increase in δ18O values (˜7-9‰) over a short distance (<200 m) suggests marked cooling of hydrothermal fluid from ˜350°C to less than 130°C either just before or during discharge onto the

  16. Effect of the oxygen non-stoichiometry on the damage threshold of the SiO2-δ system optical coatings

    NASA Astrophysics Data System (ADS)

    Guretskii, S. A.; Luginets, A. M.; Kalanda, N. A.; Mashchenko, A. G.; Kutavichyus, U. P.; Zaporozhenko, J. U.; Tushina, C. D.

    2005-04-01

    The results of the coulometric study of the processes of oxygen sorption-desorption in optical coatings (OCs) of the SiO2-δ system deposited by the electron-beam sputtering technique are presented. The character of structural transformations occurring when the coatings under-go polythermal annealing within the temperature range from 200 to 1000°C and at oxygen partial pressures pO2=102-105 Pa has been established. It has been ascertained that the intensity of photoluminescence of the OCs and shift of the absorption edge depends on the annealing condition within the temperature range from 400 to 550°C in the dehydrated oxygen atmosphere that is caused by the coagulation of silicon atoms with their subsequent oxidization. The dependence of the optical damage thresholds of the SiO2-δ on structural defects has been studied.

  17. Enhancing dissolved oxygen control using an on-line hybrid fuzzy-neural soft-sensing model-based control system in an anaerobic/anoxic/oxic process.

    PubMed

    Huang, Mingzhi; Wan, Jinquan; Hu, Kang; Ma, Yongwen; Wang, Yan

    2013-12-01

    An on-line hybrid fuzzy-neural soft-sensing model-based control system was developed to optimize dissolved oxygen concentration in a bench-scale anaerobic/anoxic/oxic (A(2)/O) process. In order to improve the performance of the control system, a self-adapted fuzzy c-means clustering algorithm and adaptive network-based fuzzy inference system (ANFIS) models were employed. The proposed control system permits the on-line implementation of every operating strategy of the experimental system. A set of experiments involving variable hydraulic retention time (HRT), influent pH (pH), dissolved oxygen in the aerobic reactor (DO), and mixed-liquid return ratio (r) was carried out. Using the proposed system, the amount of COD in the effluent stabilized at the set-point and below. The improvement was achieved with optimum dissolved oxygen concentration because the performance of the treatment process was optimized using operating rules implemented in real time. The system allows various expert operational approaches to be deployed with the goal of minimizing organic substances in the outlet while using the minimum amount of energy.

  18. Low oxygen induces the type III secretion system in Pseudomonas aeruginosa via modulation of the small RNAs rsmZ and rsmY.

    PubMed

    O'Callaghan, Julie; Reen, F Jerry; Adams, Claire; O'Gara, Fergal

    2011-12-01

    A steep oxygen gradient within the mucus of the cystic fibrosis (CF) lung combined with the biofilm mode of bacterial growth forces respiratory pathogens to adapt to varying oxygen availability. This study presents the novel finding that the Pseudomonas aeruginosa response to limiting oxygen stress includes induction of its type III secretion system (T3SS), which subsequently contributes towards host cell cytotoxicity. In P. aeruginosa, the global anaerobic response regulator Anr perceives low oxygen and subsequently triggers gene expression of a range of target genes, including the response regulator narL. Here we demonstrate that microaerobic induction of the T3SS is dependent on Anr, and that this is mediated through direct NarL transcriptional repression of the sRNAs rsmY and rsmZ, allowing free RsmA protein to positively regulate the T3SS. This study reveals a novel interplay between the Anr-NarL and RsmAYZ regulatory circuits, and introduces RsmA as an important regulator during P. aeruginosa adaptation to a low-oxygen environment.

  19. Oxygen supplies in disaster management.

    PubMed

    Blakeman, Thomas C; Branson, Richard D

    2013-01-01

    Mass casualty events and disasters, both natural and human-generated, occur frequently around the world and can generate scores of injured or ill victims in need of resources. Of the available medical supplies, oxygen remains the critical consumable resource in disaster management. Strategic management of oxygen supplies in disaster scenarios remains a priority. Hospitals have large supplies of liquid oxygen and a supply of compressed gas oxygen cylinders that allow several days of reserve, but a large influx of patients from a disaster can strain these resources. Most backup liquid oxygen supplies are attached to the main liquid system and supply line. In the event of damage to the main system, the reserve supply is rendered useless. The Strategic National Stockpile supplies medications, medical supplies, and equipment to disaster areas, but it does not supply oxygen. Contracted vendors can deliver oxygen to alternate care facilities in disaster areas, in the form of concentrators, compressed gas cylinders, and liquid oxygen. Planning for oxygen needs following a disaster still presents a substantial challenge, but alternate care facilities have proven to be valuable in relieving pressure from the mass influx of patients into hospitals, especially for those on home oxygen who require only an electrical source to power their oxygen concentrator.

  20. Electrical and Magnetic Properties of the Percolative Yttrium BARIUM(2) COPPER(3) OXYGEN(7-DELTA) - YTTRIUM(2) Barium Copper OXYGEN(5) Systems

    NASA Astrophysics Data System (ADS)

    Sedghi Gamchi, Hassan

    1995-01-01

    The electrical and magnetic behaviour of the mixed two phase, percolative system, YBCO(123)-YBCO(211) has been investigated. The normal-state resistivity of this system is best represented by a variable range hopping (VRH) model in which the electronic states of the system are localized. From this model the localization length, alpha^{-1} and the activation energies involved in the hopping process have been determined. The form of the superconducting resistive transition is shown to depend strongly on the intergranular weak-link structure. The resistivity tails have been interpreted in terms of the phase slip and thermally activated flux creep models with the magnetic field dependence of the activation energies found to follow an inverse power-law relationship. A detailed investigation of the ac magnetic susceptibility of this system has shown that the flux pinning energies were found to decrease rapidly as the Y_ {211} concentration increased. These measurements support the view that the observed pinning is associated with the intergranular weak-link system rather than with the intrinsic crystalline material. Changes in the H-T phase diagram have been established as a function of composition and it is found that the irreversibility line (IL) is consistent with H^{rm q}~ (1-t), while the IL moves to lower temperatures and magnetic fields as the intergranular pinning strengths are decreased. DC field dependent ac susceptibility results have been adequately described by a critical state model in which the critical current density is given by alpha(T)/(H_{rm o} + H_{{dc }})^{rm n}. The functional relationship of the material dependent parameter alpha(T) has been determined. The hysteresis behaviour of chi_{ {ac}} H_ {{dc}} in a cycled dc magnetic field have been measured and the average lower critical field, H_{{clg }} for the superconducting grains has been established and its temperature dependence determined. The internal relationship between the susceptibility