Science.gov

Sample records for addressing gas generation

  1. NEW APPROACH TO ADDRESSING GAS GENERATION IN RADIOACTIVE MATERIAL PACKAGING

    SciTech Connect

    Watkins, R; Leduc, D; Askew, N

    2009-06-25

    Safety Analysis Reports for Packaging (SARP) document why the transportation of radioactive material is safe in Type A(F) and Type B shipping containers. The content evaluation of certain actinide materials require that the gas generation characteristics be addressed. Most packages used to transport actinides impose extremely restrictive limits on moisture content and oxide stabilization to control or prevent flammable gas generation. These requirements prevent some users from using a shipping container even though the material to be shipped is fully compliant with the remaining content envelope including isotopic distribution. To avoid these restrictions, gas generation issues have to be addressed on a case by case basis rather than a one size fits all approach. In addition, SARP applicants and review groups may not have the knowledge and experience with actinide chemistry and other factors affecting gas generation, which facility experts in actinide material processing have obtained in the last sixty years. This paper will address a proposal to create a Gas Generation Evaluation Committee to evaluate gas generation issues associated with Safety Analysis Reports for Packaging material contents. The committee charter could include reviews of both SARP approved contents and new contents not previously evaluated in a SARP.

  2. Liquid propellant gas generators

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The design of gas generators intended to provide hot gases for turbine drive is discussed. Emphasis is placed on the design and operation of bipropellant gas generators because of their wider use. Problems and limitations involved in turbine operation due to temperature effects are analyzed. Methods of temperature control of gas turbines and combustion products are examined. Drawings of critical sections of gas turbines to show their operation and areas of stress are included.

  3. Fastrac Gas Generator Testing

    NASA Technical Reports Server (NTRS)

    Nesman, Tomas E.; Dennis, Jay

    1999-01-01

    A rocket engine gas generator component development test was recently conducted at the Marshall Space Flight Center. This gas generator was intended to power a rocket engine turbopump by the combustion of Lox and RP-1. The testing demonstrated design requirements for start sequence, wall compatibility, performance, and stable combustion. During testing the gas generator injector was modified to improve distribution of outer wall coolant and the igniter boss was modified to investigate the use of a pyrotechnic igniter, Expected chamber pressure oscillations at longitudinal acoustic modes were measured for three different chamber lengths tested. High amplitude discrete oscillations occurred in the chamber-alone configurations when chamber acoustic modes coupled with feed-system acoustics modes. For the full gas generator configuration, which included the turbine inlet manifold simulator, high amplitude oscillations occurred only at off-design very low power levels. This testing led to a successful gas generator design for the Fastrac 60,000 lb thrust engine.

  4. Fastrac Gas Generator Testing

    NASA Technical Reports Server (NTRS)

    Nesman, Tomas E.; Dennis, Jay

    2001-01-01

    A rocket engine gas generator component development test was recently conducted at the Marshall Space Flight Center. This gas generator is intended to power a rocket engine turbopump by the combustion of Lox and RP-1. The testing demonstrated design requirements for start sequence, wall compatibility, performance, and stable combustion. During testing the gas generator injector was modified to improve distribution of outer wall coolant and the igniter boss was modified to investigate the use of a pyrotechnic igniter. Expected chamber pressure oscillations at longitudinal acoustic mode were measured for three different chamber lengths tested. High amplitude discrete oscillations resulted in the chamber-alone configurations when chamber acoustic modes coupled with feed-system acoustics modes. For the full gas generator configuration, which included a turbine inlet manifold, high amplitude oscillations occurred only at off-design very low power levels. This testing led to a successful gas generator design for the Fastrac 60,000 lb thrust engine.

  5. Reducing gas generators and methods for generating a reducing gas

    SciTech Connect

    Scotto, Mark Vincent; Perna, Mark Anthony

    2015-11-03

    One embodiment of the present invention is a unique reducing gas generator. Another embodiment is a unique method for generating a reducing gas. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for generating reducing gas. Further embodiments, forms, features, aspects, benefits, and advantages of the present application will become apparent from the description and figures provided herewith.

  6. Addressing biogenic greenhouse gas emissions from hydropower in LCA.

    PubMed

    Hertwich, Edgar G

    2013-09-01

    The ability of hydropower to contribute to climate change mitigation is sometimes questioned, citing emissions of methane and carbon dioxide resulting from the degradation of biogenic carbon in hydropower reservoirs. These emissions are, however, not always addressed in life cycle assessment, leading to a bias in technology comparisons, and often misunderstood. The objective of this paper is to review and analyze the generation of greenhouse gas emissions from reservoirs for the purpose of technology assessment, relating established emission measurements to power generation. A literature review, data collection, and statistical analysis of methane and CO2 emissions are conducted. In a sample of 82 measurements, methane emissions per kWh hydropower generated are log-normally distributed, ranging from micrograms to 10s of kg. A multivariate regression analysis shows that the reservoir area per kWh electricity is the most important explanatory variable. Methane emissions flux per reservoir area are correlated with the natural net primary production of the area, the age of the power plant, and the inclusion of bubbling emissions in the measurement. Even together, these factors fail to explain most of the variation in the methane flux. The global average emissions from hydropower are estimated to be 85 gCO2/kWh and 3 gCH4/kWh, with a multiplicative uncertainty factor of 2. GHG emissions from hydropower can be largely avoided by ceasing to build hydropower plants with high land use per unit of electricity generated. PMID:23909506

  7. Hydrogen rich gas generator

    NASA Technical Reports Server (NTRS)

    Houseman, J. (Inventor)

    1976-01-01

    A process and apparatus is described for producing a hydrogen rich gas by introducing a liquid hydrocarbon fuel in the form of a spray into a partial oxidation region and mixing with a mixture of steam and air that is preheated by indirect heat exchange with the formed hydrogen rich gas, igniting the hydrocarbon fuel spray mixed with the preheated mixture of steam and air within the partial oxidation region to form a hydrogen rich gas.

  8. Hydrogen rich gas generator

    NASA Technical Reports Server (NTRS)

    Houseman, J.; Rupe, J. H.; Kushida, R. O. (Inventor)

    1976-01-01

    A process and apparatus is described for producing a hydrogen rich gas by injecting air and hydrocarbon fuel at one end of a cylindrically shaped chamber to form a mixture and igniting the mixture to provide hot combustion gases by partial oxidation of the hydrocarbon fuel. The combustion gases move away from the ignition region to another region where water is injected to be turned into steam by the hot combustion gases. The steam which is formed mixes with the hot gases to yield a uniform hot gas whereby a steam reforming reaction with the hydrocarbon fuel takes place to produce a hydrogen rich gas.

  9. New generation of content addressable memories for associative processing

    NASA Astrophysics Data System (ADS)

    Lewis, H. G., Jr.; Giambalov, Paul

    2000-05-01

    Content addressable memories (CAMS) store both key and association data. A key is presented to the CAN when it is searched and all of the addresses are scanned in parallel to find the address referenced by the key. When a match occurs, the corresponding association is returned. With the explosion of telecommunications packet switching protocols, large data base servers, routers and search engines a new generation of dense sub-micron high throughput CAMS has been developed. The introduction of this paper presents a brief history and tutorial on CAMS, their many uses and advantages, and describes the architecture and functionality of several of MUSIC Semiconductors CAM devices. In subsequent sections of the paper we address using Associative Processing to accommodate the continued increase in sensor resolution, number of spectral bands, required coverage, the desire to implement real-time target cueing, and the data flow and image processing required for optimum performance of reconnaissance and surveillance Unmanned Aerial Vehicles (UAVs). To be competitive the system designer must provide the most computational power, per watt, per dollar, per cubic inch, within the boundaries of cost effective UAV environmental control systems. To address these problems we demonstrate leveraging DARPA and DoD funded Commercial Off-the-Shelf technology to integrate CAM based Associative Processing into a real-time heterogenous multiprocessing system for UAVs and other platforms with limited weight, volume and power budgets.

  10. Addressing Benefits, Risks and Consent in Next Generation Sequencing Studies

    PubMed Central

    Meller, R

    2016-01-01

    The sequencing of the human genome and technological advances in DNA sequencing have led to a revolution with respect to DNA sequencing and its potential to diagnose genetic disorders. However, requests for open access to genomic data must be balanced against the guiding principles of the Common Rule for human subject research. Unfortunately, the risks to patients involved in genomic studies are still evolving and as such may not be clear to learned and well-intentioned scientists. Central to this issue are the strategies that enable human participants in such studies to remain anonymous, or de-identified. The wealth of genomic data on the Internet in genomic data repositories and other databases has enabled de-identified data to be broken and research subjects to be identified. The security of de-identification neglects the fact that DNA itself is an identifying element. Therefore, it is questionable whether data security standards can ever truly protect the identity of a patient, under the current conditions or in the future. As Big Data methodologies advance, additional sources of data may enable the re-identification of patients enrolled in next-generation sequencing (NGS) studies. As such, it is time to re-evaluate the risks of sharing genomic data and establish new guidelines for good practices. In this commentary, I address the challenges facing federally funded investigators who need to strike a balance between compliance with federal (US) rules for human subjects and the recent requirement for open access/sharing of data from National Institute for Health (NIH)-funded studies involving human subjects. PMID:27375922

  11. WIPP Gas-Generation Experiments

    SciTech Connect

    Frank S. Felicione; Steven M. Frank; Dennis D. Keiser

    2007-05-01

    An experimental investigation was conducted for gas generation in contact-handled transuranic (CH TRU) wastes subjected for several years to conditions similar to those expected to occur at the Waste Isolation Pilot Plant (WIPP) should the repository eventually become inundated with brine. Various types of actual CH TRU wastes were placed into 12 corrosion-resistant vessels. The vessels were loosely filled with the wastes, which were submerged in synthetic brine having the same chemical composition as that in the WIPP vicinity. The vessels were also inoculated with microbes found in the Salado Formation at WIPP. The vessels were sealed, purged, and the approximately 750 ml headspace in each vessel was pressurized with nitrogen gas to approximately 146 atmospheres to create anoxic conditions at the lithostatic pressure estimated in the repository were it to be inundated. The temperature was maintained at the expected 30°C. The test program objective was to measure the quantities and species of gases generated by metal corrosion, radiolysis, and microbial activity. These data will assist in the specification of the rates at which gases are produced under inundated repository conditions for use in the WIPP Performance Assessment computer models. These experiments were very carefully designed, constructed, instrumented, and performed. Approximately 6 1/2 years of continuous, undisturbed testing were accumulated. Several of the vessels showed significantly elevated levels of generated gases, virtually all of which was hydrogen. Up to 4.2% hydrogen, by volume, was measured. Only small quantities of other gases, principally carbon dioxide, were detected. Gas generation was found to depend strongly on the waste composition. The maximum hydrogen generation occurred in vessels containing carbon steel. Visual examination of carbon-steel coupons confirmed the correspondence between the extent of observable corrosion and hydrogen generation. Average corrosion penetration rates

  12. CLIGEN: Addressing deficiencies in the generator and its databases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    CLIGEN is a stochastic generator that estimates daily temperatures, precipitation and other weather related phenomena. It is an intermediate model used by the Water Erosion Prediction Program (WEPP), the Wind Erosion Prediction System (WEPS), and other models that require daily weather observations....

  13. Hydrazine Gas Generator Program. [space shuttles

    NASA Technical Reports Server (NTRS)

    Kusak, L.; Marcy, R. D.

    1975-01-01

    The design and fabrication of a flight gas generator for the space shuttle were investigated. Critical performance parameters and stability criteria were evaluated as well as a scaling laws that could be applied in designing the flight gas generator. A test program to provide the necessary design information was included. A structural design, including thermal and stress analysis, and two gas generators were fabricated based on the results. Conclusions are presented.

  14. The Chemistry of Flammable Gas Generation

    SciTech Connect

    ZACH, J.J.

    2000-10-30

    The document collects information from field instrumentation, laboratory tests, and analytical models to provide a single source of information on the chemistry of flammable gas generation at the Hanford Site. It considers the 3 mechanisms of formation: radiolysis, chemical reactions, and thermal generation. An assessment of the current models for gas generation is then performed. The results are that the various phenomena are reasonably understood and modeled compared to field data.

  15. Synthesis gas generation complex and process

    SciTech Connect

    Doering, E.L.

    1989-01-17

    A synthesis gas generation complex is described including: (a) a coal gasification plant, including at least one gasifier for the gasification of coal to produce synthesis gas at a temperature of about 2000/sup 0/F to 3000/sup 0/F, the gasifier having heat exchange surfaces adapted for indirect heat exchange with steam and water; (b) a heat exchange section comprising at least one heat exchanger in gas flow communication with the gasifier, the heat exchanger comprising at least one segment adapted to generate superheated steam, and lower temperature heat exchange segments; (c) a gas cleanup section in flow communication with the heat exchanger, the cleanup section comprising means for removing particulates and H/sub 2/S from the synthesis gas; (d) a steam turbine adapted to receive and utilize superheated steam and to produce a low temperature vapor, the steam turbine driving an electrical generator.

  16. F-1 Engine Gas Generator Testing

    NASA Video Gallery

    The gas generator from an F-1 engine is test-fired at the Marshall Space Flight Center in Huntsville, Ala., on Jan. 24, 2013. Data from the 30 second test will be used in the development of advance...

  17. A semiconductor bridge ignited gas generator

    SciTech Connect

    Grubelich, M.C.; Bickes, R.W. Jr.

    1992-06-01

    Compact, lightweight, self-contained gas generator systems are required for a variety of inflation or deployment applications. We designed a generic gas generator employing a semiconductor bridge, SCB, igniter to evaluate the characteristics of the black powder propellant selected. Because of the low ignition energy requirements and rugged design of SCBs, they are ideally suited to the volume, mass and severe environments for the gas generator applications. In our design, an SCB ignited a pyrotechnic (TiH{sub 1.68}KClO{sub 4}) which was used to ignite an end-burning consolidated black powder grain. We evaluated the performance of the gas generator using a computer program developed to simulate the combustion of the end-burning propellant grain. This model is in good agreement with the data from our test firings. In addition, we examined direct SCB ignition of black powder as a function of loading pressure and firing-set current. 3 refs.

  18. A semiconductor bridge ignited gas generator

    SciTech Connect

    Grubelich, M.C.; Bickes, R.W. Jr.

    1992-01-01

    Compact, lightweight, self-contained gas generator systems are required for a variety of inflation or deployment applications. We designed a generic gas generator employing a semiconductor bridge, SCB, igniter to evaluate the characteristics of the black powder propellant selected. Because of the low ignition energy requirements and rugged design of SCBs, they are ideally suited to the volume, mass and severe environments for the gas generator applications. In our design, an SCB ignited a pyrotechnic (TiH{sub 1.68}KClO{sub 4}) which was used to ignite an end-burning consolidated black powder grain. We evaluated the performance of the gas generator using a computer program developed to simulate the combustion of the end-burning propellant grain. This model is in good agreement with the data from our test firings. In addition, we examined direct SCB ignition of black powder as a function of loading pressure and firing-set current. 3 refs.

  19. Generation and delivery device for ozone gas

    NASA Technical Reports Server (NTRS)

    Andrews, Craig C. (Inventor); Murphy, Oliver J. (Inventor)

    2002-01-01

    The present invention provides an ozone generation and delivery system that lends itself to small scale applications and requires very low maintenance. The system preferably includes an anode reservoir and a cathode phase separator each having a hydrophobic membrane to allow phase separation of produced gases from water. The hydrogen gas, ozone gas and water containing ozone may be delivered under pressure.

  20. NEXT GENERATION GAS TURBINE SYSTEMS STUDY

    SciTech Connect

    Benjamin C. Wiant; Ihor S. Diakunchak; Dennis A. Horazak; Harry T. Morehead

    2003-03-01

    Under sponsorship of the U.S. Department of Energy's National Energy Technology Laboratory, Siemens Westinghouse Power Corporation has conducted a study of Next Generation Gas Turbine Systems that embraces the goals of the DOE's High Efficiency Engines and Turbines and Vision 21 programs. The Siemens Westinghouse Next Generation Gas Turbine (NGGT) Systems program was a 24-month study looking at the feasibility of a NGGT for the emerging deregulated distributed generation market. Initial efforts focused on a modular gas turbine using an innovative blend of proven technologies from the Siemens Westinghouse W501 series of gas turbines and new enabling technologies to serve a wide variety of applications. The flexibility to serve both 50-Hz and 60-Hz applications, use a wide range of fuels and be configured for peaking, intermediate and base load duty cycles was the ultimate goal. As the study progressed the emphasis shifted from a flexible gas turbine system of a specific size to a broader gas turbine technology focus. This shift in direction allowed for greater placement of technology among both the existing fleet and new engine designs, regardless of size, and will ultimately provide for greater public benefit. This report describes the study efforts and provides the resultant conclusions and recommendations for future technology development in collaboration with the DOE.

  1. Detonation duct gas generator demonstration program

    NASA Technical Reports Server (NTRS)

    Wortman, A.; Othmer, P.; Rostafinski, W.

    1992-01-01

    An experimental demonstration is presented for the generation of detonation waves that move periodically across high speed channel flow; these waves can compress the outflow from a low pressure compressor, and thereby both reduce the compressor requirements associated with conventional gas turbines and enhance thermodynamic efficiency through isochoric energy addition. By generating transient transverse waves, rather than standing waves, shock-wave losses are reduced by an order of magnitude; the result is a Humphrey cycle augmenting the basic Brayton-cycle gas turbine. Attention is presently given to results from an experimental detonation duct.

  2. Chemical mechanisms for gas generation in Tank 241-SY-101

    SciTech Connect

    Strachan, D.M.; Pederson, L.R.; Bryan, S.A.; Ashby, E.C.; Liotta, C.; Barefield, E.K.; Meisel, D.; Jonah, C.D.; Sauer, M.C. Jr.

    1993-08-01

    The mixing of wastes at Hanford over the years has led to several safety concerns. These safety concerns fall into six categories: wastes that generate flammable gasses or gas mixtures; wastes that contain high concentrations of ferrocyanides or tanks suspected of containing large amounts of ferrocyanides; wastes that contain greater than 3 wt % total organic carbon; wastes from which toxic or noxious vapors are suspected of emanating; wastes that contain high radiolytic heat; and wastes that may contain sufficient fissile material to pose a criticality concern. This report addresses the chemistry associated with the generation of flammable gases.

  3. NNSA Administrator Addresses the Next Generation of Nuclear Security Professionals: Part 1

    SciTech Connect

    Thomas D'Agostino

    2009-07-14

    Administrator Thomas DAgostino of the National Nuclear Security Administration addressed the next generation of nuclear security professionals during the opening session of todays 2009 Department of Energy (DOE) Computational Science Graduate Fellowship Annual Conference. Administrator DAgostino discussed NNSAs role in implementing President Obamas nuclear security agenda and encouraged the computing science fellows to consider careers in nuclear security.

  4. NNSA Administrator Addresses the Next Generation of Nuclear Security Professionals: Part 2

    SciTech Connect

    Thomas D'Agostino

    2009-07-14

    Administrator Thomas DAgostino of the National Nuclear Security Administration addressed the next generation of nuclear security professionals during the opening session of todays 2009 Department of Energy (DOE) Computational Science Graduate Fellowship Annual Conference. Administrator DAgostino discussed NNSAs role in implementing President Obamas nuclear security agenda and encouraged the computing science fellows to consider careers in nuclear security.

  5. NNSA Administrator Addresses the Next Generation of Nuclear Security Professionals: Part 2

    ScienceCinema

    Thomas D'Agostino

    2010-09-01

    Administrator Thomas DAgostino of the National Nuclear Security Administration addressed the next generation of nuclear security professionals during the opening session of todays 2009 Department of Energy (DOE) Computational Science Graduate Fellowship Annual Conference. Administrator DAgostino discussed NNSAs role in implementing President Obamas nuclear security agenda and encouraged the computing science fellows to consider careers in nuclear security.

  6. NNSA Administrator Addresses the Next Generation of Nuclear Security Professionals: Part 1

    ScienceCinema

    Thomas D'Agostino

    2010-09-01

    Administrator Thomas DAgostino of the National Nuclear Security Administration addressed the next generation of nuclear security professionals during the opening session of todays 2009 Department of Energy (DOE) Computational Science Graduate Fellowship Annual Conference. Administrator DAgostino discussed NNSAs role in implementing President Obamas nuclear security agenda and encouraged the computing science fellows to consider careers in nuclear security.

  7. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Inert gas generators. 154.906 Section 154.906 Shipping... Atmospheric Control in Cargo Containment Systems § 154.906 Inert gas generators. The inert gas generator must... sample the discharge of the generator for oxygen content; and (c) Have an audible and visual alarm in...

  8. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Inert gas generators. 154.906 Section 154.906 Shipping... Atmospheric Control in Cargo Containment Systems § 154.906 Inert gas generators. The inert gas generator must... sample the discharge of the generator for oxygen content; and (c) Have an audible and visual alarm in...

  9. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Inert gas generators. 154.906 Section 154.906 Shipping... Atmospheric Control in Cargo Containment Systems § 154.906 Inert gas generators. The inert gas generator must... sample the discharge of the generator for oxygen content; and (c) Have an audible and visual alarm in...

  10. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Inert gas generators. 154.906 Section 154.906 Shipping... Atmospheric Control in Cargo Containment Systems § 154.906 Inert gas generators. The inert gas generator must... sample the discharge of the generator for oxygen content; and (c) Have an audible and visual alarm in...

  11. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Inert gas generators. 154.906 Section 154.906 Shipping... Atmospheric Control in Cargo Containment Systems § 154.906 Inert gas generators. The inert gas generator must... sample the discharge of the generator for oxygen content; and (c) Have an audible and visual alarm in...

  12. Gas Generation from Actinide Oxide Materials

    SciTech Connect

    George Bailey; Elizabeth Bluhm; John Lyman; Richard Mason; Mark Paffett; Gary Polansky; G. D. Roberson; Martin Sherman; Kirk Veirs; Laura Worl

    2000-12-01

    This document captures relevant work performed in support of stabilization, packaging, and long term storage of plutonium metals and oxides. It concentrates on the issue of gas generation with specific emphasis on gas pressure and composition. Even more specifically, it summarizes the basis for asserting that materials loaded into a 3013 container according to the requirements of the 3013 Standard (DOE-STD-3013-2000) cannot exceed the container design pressure within the time frames or environmental conditions of either storage or transportation. Presently, materials stabilized and packaged according to the 3013 Standard are to be transported in certified packages (the certification process for the 9975 and the SAFKEG has yet to be completed) that do not rely on the containment capabilities of the 3013 container. Even though no reliance is placed on that container, this document shows that it is highly likely that the containment function will be maintained not only in storage but also during transportation, including hypothetical accident conditions. Further, this document, by summarizing materials-related data on gas generation, can point those involved in preparing Safety Analysis Reports for Packages (SARPs) to additional information needed to assess the ability of the primary containment vessel to contain the contents and any reaction products that might reasonably be produced by the contents.

  13. Detonation duct gas generator demonstration program

    NASA Technical Reports Server (NTRS)

    Wortman, Andrew; Brinlee, Gayl A.; Othmer, Peter; Whelan, Michael A.

    1991-01-01

    The feasibility of the generation of detonation waves moving periodically across high speed channel flow is experimentally demonstrated. Such waves are essential to the concept of compressing requirements and increasing the engine pressure compressor with the objective of reducing conventional compressor requirements and increasing the engine thermodynamic efficiency through isochoric energy addition. By generating transient transverse waves, rather than standing waves, shock wave losses are reduced by an order of magnitude. The ultimate objective is to use such detonation ducts downstream of a low pressure gas turbine compressor to produce a high overall pressure ratio thermodynamic cycle. A 4 foot long, 1 inch x 12 inch cross-section, detonation duct was operated in a blow-down mode using compressed air reservoirs. Liquid or vapor propane was injected through injectors or solenoid valves located in the plenum or the duct itself. Detonation waves were generated when the mixture was ignited by a row of spark plugs in the duct wall. Problems with fuel injection and mixing limited the air speeds to about Mach 0.5, frequencies to below 10 Hz, and measured pressure ratios of about 5 to 6. The feasibility of the gas dynamic compression was demonstrated and the critical problem areas were identified.

  14. Miniature Gas-Turbine Power Generator

    NASA Technical Reports Server (NTRS)

    Wiberg, Dean; Vargo, Stephen; White, Victor; Shcheglov, Kirill

    2003-01-01

    A proposed microelectromechanical system (MEMS) containing a closed- Brayton-cycle turbine would serve as a prototype of electric-power generators for special applications in which high energy densities are required and in which, heretofore, batteries have been used. The system would have a volume of about 6 cm3 and would operate with a thermal efficiency >30 percent, generating up to 50 W of electrical power. The energy density of the proposed system would be about 10 times that of the best battery-based systems now available, and, as such, would be comparable to that of a fuel cell. The working gas for the turbine would be Xe containing small quantities of CO2, O2, and H2O as gaseous lubricants. The gas would be contained in an enclosed circulation system, within which the pressure would typically range between 5 and 50 atm (between 0.5 and 5 MPa). The heat for the Brayton cycle could be supplied by any of a number of sources, including a solar concentrator or a combustor burning a hydrocarbon or other fuel. The system would include novel heat-transfer and heat-management components. The turbine would be connected to an electric power generator/starter motor. The system would include a main rotor shaft with gas bearings; the bearing surfaces would be made of a ceramic material coated with nanocrystalline diamond. The shaft could withstand speed of 400,000 rpm or perhaps more, with bearing-wear rates less than 10(exp -)4 those of silicon bearings and 0.05 to 0.1 those of SiC bearings, and with a coefficient of friction about 0.1 that of Si or SiC bearings. The components of the system would be fabricated by a combination of (1) three-dimensional xray lithography and (2) highly precise injection molding of diamond-compatible metals and ceramic materials. The materials and fabrication techniques would be suitable for mass production. The disadvantages of the proposed system are that unlike a battery-based system, it could generate a perceptible amount of sound, and

  15. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Inert gas generator: Location. 154.908 Section 154.908... Atmospheric Control in Cargo Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed in paragraph (b) of this section, an inert gas generator must be located in the main...

  16. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Inert gas generator: Location. 154.908 Section 154.908... Atmospheric Control in Cargo Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed in paragraph (b) of this section, an inert gas generator must be located in the main...

  17. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Inert gas generator: Location. 154.908 Section 154.908... Atmospheric Control in Cargo Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed in paragraph (b) of this section, an inert gas generator must be located in the main...

  18. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Inert gas generator: Location. 154.908 Section 154.908... Atmospheric Control in Cargo Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed in paragraph (b) of this section, an inert gas generator must be located in the main...

  19. 46 CFR 154.908 - Inert gas generator: Location.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Inert gas generator: Location. 154.908 Section 154.908... Atmospheric Control in Cargo Containment Systems § 154.908 Inert gas generator: Location. (a) Except as allowed in paragraph (b) of this section, an inert gas generator must be located in the main...

  20. Hydrazine gas generator performance on Space Shuttle

    NASA Technical Reports Server (NTRS)

    Patterson, I. J.; Swink, D. G.

    1983-01-01

    The design, functions, performance, and applications of the hydrazine gas generators (GG) on the STS are detailed. The GGs provide gas horse power for the APUs that drive the hydraulic pumps on the SRBs, which have two cross-linked systems. The Orbiter has three-cross-linked APU systems, used for gimballing the main engine and booster nozzles, actuating the main engine fuel valves and the ET umbilical disconnect, actuation of the control surfaces, and powering the landing gear, brakes, and nose wheel steering. The major design components of the Orbiter GGs are an injector, a catalyst bed, a decomposition chamber, an exhaust nozzle, and an interface structure, with the main structural material being Hasteloy B. Hydrazine injected and dispersed into the catalyst bed decomposes into gas and exits for expansion in an APU turbine. Twenty-six GGs have flown on missions STS-1 through STS-6 with over three tons of hydrazine having been expended over 44 hr of operations, as no refurbishment to that point was necessary.

  1. Dual entry radial turbine gas generator

    SciTech Connect

    Mowill, R.J.

    1987-02-10

    This patent describes a high efficiency, single spool gas turbine gas generator comprising: (a) compressor means for providing an overall pressure ratio of greater than about 15:1, the compressor means including: (i) a first stage, double-entry centrifugal air compressor having a pair of entrances and a common exit, (ii) a second stage, centrifugal air compressor positioned adjacent to the first stage compressor, the second compressor stage having an entrance that is flow-connected to the first stage common exit and also having a second stage exit, and (iii) a shaft assembly for mechanically interconnecting the first and the second stage for rotation at the same angular speed; (b) combustor means operatively connected to the second stage exit for receiving the compressed air and combusting fuel using the compressed air to generate combustion gases; and (c) a single stage radial inflow turbine having an inlet and an outlet, the turbine being operatively connected directly to the shaft assembly drive and also being flow connected to the combustor means for receiving at the turbine inlet, and partially expanding, the combustion gases.

  2. Preliminary Results of Solid Gas Generator Micropropulsion

    NASA Technical Reports Server (NTRS)

    deGroot, Wilhelmus A.; Reed, Brian D.; Brenizer, Marshall

    1999-01-01

    A decomposing solid thruster concept, which creates a more benign thermal and chemical environment than solid propellant combustion, while maintaining, performance similar to solid combustion, is described. A Micro-Electro-Mechanical (MEMS) thruster concept with diode laser and fiber-optic initiation is proposed, and thruster components fabricated with MEMS technology are presented. A high nitrogen content solid gas generator compound is evaluated and tested in a conventional axisymmetric thrust chamber with nozzle throat area ratio of 100. Results show incomplete decomposition of this compound in both low pressure (1 kPa) and high pressure (1 MPa) environments, with decomposition of up to 80% of the original mass. Chamber pressures of 1.1 MPa were obtained, with maximum calculated thrust of approximately 2.7 N. Resistively heated wires and resistively heated walls were used to initiate decomposition. Initiation tests using available lasers were unsuccessful, but infrared spectra of the compound show that the laser initiation tests used inappropriate wavelengths for optimal propellant absorption. Optimal wavelengths for laser ignition were identified. Data presented are from tests currently in progress. Alternative solid gas generator compounds are being evaluated for future tests.

  3. Generating local addresses and communication sets for data-parallel programs

    NASA Technical Reports Server (NTRS)

    Chatterjee, Siddhartha; Gilbert, John R.; Long, Fred J. E.; Schreiber, Robert; Teng, Shang-Hua

    1993-01-01

    Generating local addresses and communication sets is an important issue in distributed-memory implementations of data-parallel languages such as High Performance FORTRAN. We show that, for an array A affinely aligned to a template that is distributed across p processors with a cyclic(k) distribution and a computation involving the regular section A(l:h:s), the local memory access sequence for any processor is characterized by a finite state machine of at most k states. We present fast algorithms for computing the essential information about these state machines, and extend the framework to handle multidimensional arrays. We also show how to generate communication sets using the state machine approach. Performance results show that this solution requires very little run-time overhead and acceptable preprocessing time.

  4. Generating local addresses and communication sets for data-parallel programs

    NASA Technical Reports Server (NTRS)

    Chatterjee, Siddhartha; Gilbert, John R.; Long, Fred J. E.; Schreiber, Robert; Teng, Shang-Hua

    1993-01-01

    Generating local addresses and communication sets is an important issue in distributed-memory implementations of data-parallel languages such as High Performance Fortran. We show that for an array A affinely aligned to a template that is distributed across p processors with a cyclic(k) distribution, and a computation involving the regular section A, the local memory access sequence for any processor is characterized by a finite state machine of at most k states. We present fast algorithms for computing the essential information about these state machines, and extend the framework to handle multidimensional arrays. We also show how to generate communication sets using the state machine approach. Performance results show that this solution requires very little runtime overhead and acceptable preprocessing time.

  5. Method and composition for generating nitrogen gas

    SciTech Connect

    Pietz, J.F.

    1988-01-26

    A solid composition is described for generating nitrogen gas substantially free of noxious and toxic impurities for inflating an air cushion in a vehicle passenger restraint system and capable of substantially fully inflating such cushion in the elapsed time between the occurrence of a primary collision of the vehicle with another object and secondary collisions occurring as a result thereof; comprising a mixture of alkali metal azide and at least a stoichiometric amount of a metal oxide selected from the group consisting of iron, titanium and copper oxides and mixtures thereof. The metal oxide is capable of reacting exothermically with the alkaki metal azide and wherein the metal of the oxide is lower in the electromotive series than the alkali metal of the azide and is a metal other than (the) an alkali metal.

  6. Electric field-free gas breakdown in explosively driven generators

    SciTech Connect

    Shkuratov, Sergey I.; Baird, Jason; Talantsev, Evgueni F.; Altgilbers, Larry L.

    2010-07-15

    All known types of gas discharges require an electric field to initiate them. We are reporting on a unique type of gas breakdown in explosively driven generators that does not require an electric field.

  7. Fuel cell generator containing a gas sealing means

    DOEpatents

    Makiel, J.M.

    1987-02-03

    A high temperature solid electrolyte electrochemical generator is made, operating with flowing fuel gas and oxidant gas, the generator having a thermal insulation layer, and a sealing means contacting or contained within the insulation, where the sealing means is effective to control the contact of the various gases utilized in the generator. 5 figs.

  8. Fuel cell generator containing a gas sealing means

    DOEpatents

    Makiel, Joseph M.

    1987-01-01

    A high temperature solid electrolyte electrochemical generator is made, operating with flowing fuel gas and oxidant gas, the generator having a thermal insulation layer, and a sealing means contacting or contained within the insulation, where the sealing means is effective to control the contact of the various gases utilized in the generator.

  9. Electrothermal gas generator: Development and qualification of the control electronics

    NASA Astrophysics Data System (ADS)

    Matthaeus, G.; Schmitz, H. D.

    1986-07-01

    The development and qualification of an electronic control circuitry for an electrothermal or catalytic hydrazine gas generator system is described. The circuitry, named manual override, controls the gas pressure in a tank using a pressure transducer and the gas generator to keep the pressure constant within narrow tolerances. The present pressure can be varied by ground command, enabling a variable thrust of the gas fed cold gas thrusters. The automatic loop can be switched off and the tank pressure be controlled by ground command. Two manual overrides SN01 and SN02 were qualified.

  10. 21 CFR 866.2580 - Gas-generating device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gas-generating device. 866.2580 Section 866.2580 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2580 Gas-generating...

  11. 21 CFR 866.2580 - Gas-generating device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Gas-generating device. 866.2580 Section 866.2580 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2580 Gas-generating...

  12. 21 CFR 866.2580 - Gas-generating device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Gas-generating device. 866.2580 Section 866.2580 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2580 Gas-generating...

  13. 21 CFR 866.2580 - Gas-generating device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Gas-generating device. 866.2580 Section 866.2580 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2580 Gas-generating...

  14. 21 CFR 866.2580 - Gas-generating device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Gas-generating device. 866.2580 Section 866.2580 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2580 Gas-generating...

  15. Transition metal catalysis in the generation of natural gas

    SciTech Connect

    Mango, F.D.

    1995-12-31

    The view that natural gas is thermolytic, coming from decomposing organic debris, has remained almost unchallenged for nearly half a century. Disturbing contradictions exist, however: Oil is found at great depth, at temperatures where only gas should exist and oil and gas deposits show no evidence of the thermolytic debris indicative of oil decomposing to gas. Moreover, laboratory attempts to duplicate the composition of natural gas, which is typically between 60 and 95+ wt% methane in C{sub 1}-C{sub 4}, have produced insufficient amounts of methane (10 to 60%). It has been suggested that natural gas may be generated catalytically, promoted by the transition metals in carbonaceous sedimentary rocks. This talk will discuss experimental results that support this hypothesis. Various transition metals, as pure compounds and in source rocks, will be shown to generate a catalytic gas that is identical to natural gas. Kinetic results suggest robust catalytic activity under moderate catagenetic conditions.

  16. NEXT GENERATION GAS TURBINE (NGGT) SYSTEMS STUDY

    SciTech Connect

    Unknown

    2001-12-05

    , both in terms of incorporation of technology into current products, as well as to an NGGT product. In summary, potential program costs are shown for development of the candidate systems along with the importance of future DOE enabling participation. Three main conclusions have been established via this study: (1) Rapid recent changes within the power generation regulatory environment and the resulting ''bubble'' of gas turbine orders has altered the timing and relative significance associated with the conclusions of the ADL study upon which the original DOE NGGT solicitation was based. (2) Assuming that the relevant technologies were developed and available for an NGGT market opportunity circa 2010, the top candidate system that meets or exceeds the DOE PRDA requirements was determined to be a hybrid aero-derivative/heavy duty concept. (3) An investment by DOE of approximately $23MM/year to develop NGGT technologies near/mid term for validation and migration into a reasonable fraction of the installed base of GE F-class products could be leveraged into $1.2B Public Benefit, with greatest benefits resulting from RAM improvements. In addition to the monetary Public Benefit, there is also significant benefit in terms of reduced energy consumption, and reduced power plant land usage.

  17. Estimating the Health Effects of Greenhouse Gas Mitigation Strategies: Addressing Parametric, Model, and Valuation Challenges

    PubMed Central

    Hess, Jeremy J.; Ebi, Kristie L.; Markandya, Anil; Balbus, John M.; Wilkinson, Paul; Haines, Andy; Chalabi, Zaid

    2014-01-01

    simultaneously improving health. Citation: Remais JV, Hess JJ, Ebi KL, Markandya A, Balbus JM, Wilkinson P, Haines A, Chalabi Z. 2014. Estimating the health effects of greenhouse gas mitigation strategies: addressing parametric, model, and valuation challenges. Environ Health Perspect 122:447–455; http://dx.doi.org/10.1289/ehp.1306744 PMID:24583270

  18. Addressing Human Variability in Next-Generation Human Health Risk Assessments of Environmental Chemicals

    PubMed Central

    Bois, Frederic Y.; Chiu, Weihsueh A.; Hattis, Dale; Rusyn, Ivan; Guyton, Kathryn Z.

    2012-01-01

    Background: Characterizing variability in the extent and nature of responses to environmental exposures is a critical aspect of human health risk assessment. Objective: Our goal was to explore how next-generation human health risk assessments may better characterize variability in the context of the conceptual framework for the source-to-outcome continuum. Methods: This review was informed by a National Research Council workshop titled “Biological Factors that Underlie Individual Susceptibility to Environmental Stressors and Their Implications for Decision-Making.” We considered current experimental and in silico approaches, and emerging data streams (such as genetically defined human cells lines, genetically diverse rodent models, human omic profiling, and genome-wide association studies) that are providing new types of information and models relevant for assessing interindividual variability for application to human health risk assessments of environmental chemicals. Discussion: One challenge for characterizing variability is the wide range of sources of inherent biological variability (e.g., genetic and epigenetic variants) among individuals. A second challenge is that each particular pair of health outcomes and chemical exposures involves combinations of these sources, which may be further compounded by extrinsic factors (e.g., diet, psychosocial stressors, other exogenous chemical exposures). A third challenge is that different decision contexts present distinct needs regarding the identification—and extent of characterization—of interindividual variability in the human population. Conclusions: Despite these inherent challenges, opportunities exist to incorporate evidence from emerging data streams for addressing interindividual variability in a range of decision-making contexts. PMID:23086705

  19. Gas Generation Testing of Neptunium Oxide at Elevated Temperature

    SciTech Connect

    Duffey, JM

    2004-01-30

    Elevated temperature gas generation tests have been conducted using neptunium dioxide produced on a laboratory scale using the HB-Line Phase II flowsheet. These tests were performed to determine what effect elevated temperatures would have on the neptunium dioxide in comparison to neptunium dioxide tested at ambient temperature. The headspace gas compositions following storage at elevated temperatures associated with normal conditions of transport (NCT) have been measured. These test results show an increase in hydrogen generation rate at elevated temperature and significant removal of oxygen from the headspace gas. The elevated temperature gas generation tests described in this report involved heating small test vessels containing neptunium dioxide and measuring the headspace gas pressure and composition at the end of the test period. Four samples were used in these tests to evaluate the impact of process variables on the gas generation rate. Two samples were calcined to 600 degrees Celsius and two were calcined to 650 degrees Celsius. Each test vessel contained approximately 9.5 g of neptunium dioxide. Following exposure to 75 per cent relative humidity (RH) for five days, these samples were loaded in air and then heated to between 105 and 115 degrees Celsius for about one month. At the conclusion of the test period, the headspace gas of each container was analyzed using a micro-gas chromatograph installed in the glovebox where the experiments were conducted. The pressure, volume, and composition data for the headspace gas samples were used to calculate average H2 generation rates.

  20. Densified biomass can cost-effectively mitigate greenhouse gas emissions and address energy security in thermal applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Determining the life cycle greenhouse gas benefits of biofuels has been critical for quantifying their potential for meeting governmental mitigation targets. Little work has been conducted to determine the life cycle greenhouse gas benefits of using biomass for heat or power generation, even though ...

  1. The greenhouse impact of unconventional gas for electricity generation

    NASA Astrophysics Data System (ADS)

    Hultman, Nathan; Rebois, Dylan; Scholten, Michael; Ramig, Christopher

    2011-10-01

    New techniques to extract natural gas from unconventional resources have become economically competitive over the past several years, leading to a rapid and largely unanticipated expansion in natural gas production. The US Energy Information Administration projects that unconventional gas will supply nearly half of US gas production by 2035. In addition, by significantly expanding and diversifying the gas supply internationally, the exploitation of new unconventional gas resources has the potential to reshape energy policy at national and international levels—altering geopolitics and energy security, recasting the economics of energy technology investment decisions, and shifting trends in greenhouse gas (GHG) emissions. In anticipation of this expansion, one of the perceived core advantages of unconventional gas—its relatively moderate GHG impact compared to coal—has recently come under scrutiny. In this paper, we compare the GHG footprints of conventional natural gas, unconventional natural gas (i.e. shale gas that has been produced using the process of hydraulic fracturing, or 'fracking'), and coal in a transparent and consistent way, focusing primarily on the electricity generation sector. We show that for electricity generation the GHG impacts of shale gas are 11% higher than those of conventional gas, and only 56% that of coal for standard assumptions.

  2. Packaging of large-area individually addressable micromirror arrays for the next generation space telescope

    NASA Astrophysics Data System (ADS)

    Lu, GuoQuan; Calata, J.; Wen, S.; Dutta, Sanghamitra B.; Zheng, Yun; Stahl, C.; Shu, Peter K.

    2002-04-01

    One of NASA's challenging projects for advancing the exploration of space is the development and deployment of the Next Generation Space Telescope (NGST) for superseding the existing Hubble Space Telescope. The NGST will be equipped with several camera/spectrometer systems including a 0.6 to 5 micron Multi-Object-Spectrometer. To selectively direct light rays from different regions of space into the spectrometer, an option is to use individually addressable micro-electro-mechanical-mirror arrays serving as the slit mask for the spectrometer. The NASA team at Goddard Space Flight Center has designed an integrated micro-mirror array/CMOS driver chip that can meet the system requirements. The fabrication and testing of prototype chips have yielded promising results. To build the entire MEMS- based slit mask, a design requires accurate placement and alignment of four large (at least 9 cm X 9 cm) pieces of the integrated chips in a 2X2 mosaic pattern. In addition, the mask will have to function at temperatures below 40 K. These requirements pose a serious challenge to the packaging of these integrated MEMS chips. In this paper, we discuss a concept for attaching and aligning the large- area MEMS chips into the 2X2 mask and interconnecting it to the rest of the system. The concept makes use of the flip-chip technology to bump-bond the large chips onto a silicon substrate such that the concern for global thermo- mechanical stresses due to mismatched coefficients of thermal expansion between chip and substrate is eliminated. It also makes use of the restoring force of the solder bumps during reflow to self-align the chips. A critical experiment involving the use of 'mechanical' chips with two-dimensional arrays of bonding pads was carried out to evaluate the feasibility of the packaging concept. Preliminary results indicate that the chips can be attached to form a closely packed mosaic pattern with a relative tilt angle between the chips to less than 0.05 degree, which is

  3. Gas Generation from K East Basin Sludges - Series II Testing

    SciTech Connect

    Bryan, Samuel A.; Delegard, Calvin H.; Schmidt, Andrew J.; Sell, Rachel L.; Silvers, Kurt L.; Gano, Susan R.; Thornton, Brenda M.

    2001-03-14

    This report describes work to examine the gas generation behavior of actual K East (KE) Basin floor, pit and canister sludge. Mixed and unmixed and fractionated KE canister sludge were tested, along with floor and pit sludges from areas in the KE Basin not previously sampled. The first report in this series focused on gas generation from KE floor and canister sludge collected using a consolidated sampling technique. The third report will present results of gas generation testing of irradiated uranium fuel fragments with and without sludge addition. The path forward for management of the K Basin Sludge is to retrieve, ship, and store the sludge at T Plant until final processing at some future date. Gas generation will impact the designs and costs of systems associated with retrieval, transportation and storage of sludge.

  4. RAETRAD MODEL OF RADON GAS GENERATION, TRANSPORT, AND INDOOR ENTRY

    EPA Science Inventory

    The report describes the theoretical basis, implementation, and validation of the Radon Emanation and Transport into Dwellings (RAETRAD) model, a conceptual and mathematical approach for simulating radon (222Rn) gas generation and transport from soils and building foundations to ...

  5. Lifecycle greenhouse gas emissions of coal, conventional and unconventional natural gas for electricity generation

    EPA Science Inventory

    An analysis of the lifecycle greenhouse gas (GHG) emissions associated with natural gas use recently published by Howarth et al. (2011) stated that use of natural gas produced from shale formations via hydraulic fracturing would generate greater lifecycle GHG emissions than petro...

  6. Coupling Power Generation, Geologic CO2 Storage and Saline Groundwater Desalination to Address Growing Energy Needs in Water Constrained Regions

    NASA Astrophysics Data System (ADS)

    Davidson, C. L.; Wurstner, S. K.; Fortson, L. A.

    2010-12-01

    As humanity works to both minimize climate change and adapt to its early impacts, co-management of energy and water resources will become increasingly important. In some parts of the US, power plants have been denied permits, in part because of the significant burden placed on local water supplies by assigning new water rights for the facility’s entire design life. Water resources may be allocated 30 to 50 years into a future where water availability and quality are uncertain due to supply impacts associated with climate change and increased demand from growing populations, agriculture and industry. In many areas, particularly those with access to seawater, desalination is being employed with increasing frequency to augment conventional sources of fresh water. At the same time, many of the world’s developed nations are moving to reduce greenhouse gas emissions. One key technological option for addressing emissions from the power generation sector is CO2 capture and geologic storage (CCS). This process is both water and energy intensive for many power and industrial facilities, compounding the impact of declining water availability for plants faced with deploying CCS in a CO2-constrained future. However, a unique opportunity may exist to couple power generation and CCS by extracting and desalinating brine from the CO2 storage formation to produce fresh water. While this coupled approach is unlikely to be attractive for most CCS projects, it may represent a viable option in areas where there is demand for additional electricity but conventional water supplies are unable to meet the needs of the power generation and CO2 capture systems, or in areas where brine produced from CCS projects can be desalinated to supplement strained municipal supplies. This paper presents a preliminary analysis of the factors impacting the feasibility of coupled CCS-desalination projects. Several injection / extraction scenarios have been examined via the STOMP geochemical flow model

  7. Roadmapping the Resolution of Gas Generation Issues in Packages Containing Radioactive Waste/Materials

    SciTech Connect

    Luke, Dale Elden; Rogers, Adam Zachary; Hamp, S.

    2001-03-01

    Gas generation issues, particularly hydrogen, have been an area of concern for the transport and storage of radioactive materials and waste in the Department of Energy (DOE) complex. Potentially combustible gases can be generated through a variety of reactions, including chemical reactions and radiolytic decomposition of hydrogen-containing materials. Transportation regulations prohibit shipment of explosives and radioactive materials together. This paper discusses the major gas generation issues within the DOE Complex and the research that has been and is being conducted by the transuranic (TRU) waste, nuclear materials (NM), and spent nuclear fuels (SNF) programs within DOE’s Environmental Management (EM) organization to address gas generation concerns. This paper presents a "program level" roadmap that links technology development to program needs and identifies the probability of success in an effort to understand the programmatic risk associated with the issue of gas generation. This "program level" roadmapping involves linking technology development (and deployment) efforts to the programs’ needs and requirements for dispositioning the material/waste that generates combustible gas through radiolysis and chemical decomposition. The roadmapping effort focused on needed technical & programmatic support to the baselines (and to alternatives to the baselines) where the probability of success is low (i.e., high uncertainty) and the consequences of failure are relatively high (i.e., high programmatic risk). A second purpose for roadmapping was to provide the basis for coordinating sharing of "lessons learned" from research and development (R&D) efforts across DOE programs to increase efficiency and effectiveness in addressing gas generation issues.

  8. Using Blackboard in Library Instruction: Addressing the Learning Styles of Generations X and Y

    ERIC Educational Resources Information Center

    Costello, Barbara; Lenholt, Robert; Stryker, Judson

    2004-01-01

    Studies show that recent generations of college students have a learning style with identifiable characteristics. Library instruction efforts must adapt to these learning styles. Course management software (CMS), such as Blackboard, is one resource available to academic librarians to meet the challenges posed by the ''Net Generation.'' At Stetson…

  9. In Response to Lee Sechrest's 1992 AEA Presidential Address: "Roots: Back to Our First Generations," February 1991, 1-7.

    ERIC Educational Resources Information Center

    Lincoln, Yvonna S.; And Others

    1992-01-01

    Y. S. Lincoln and E. G. Guba consider L. Sechrest's comments on their book "Fourth Generation Evaluation" as less a criticism than an attempt to demolish. D. M. Fetterman also objects to much of Sechrest's address. E. J. Posavac generally agrees with conclusions of Welch and Sternhagen. (SLD)

  10. Modularized architecture of address generation units suitable for real-time processing MR data on an FPGA.

    PubMed

    Li, Limin; Wyrwicz, Alice M

    2016-06-01

    In this paper, we describe a modular approach to the design of an Address Generation Unit (AGU). The approach consists of development of a generic Address Generation Core (AGC) as a basic building block and the construction of an AGU from the AGCs. We illustrate this concept with AGUs capable of handling 2D- and 3D-structured data, and as well as their setup for executing 2D and 3D FFT algorithms on a Field Programmable Gate Array (FPGA). The AGUs developed using our proposed method are simple and easily expandable. Furthermore, they can potentially support irregularly structured data which are often generated from the wide variety of pulse sequences in magnetic resonance imaging. Our experimental results show that these AGUs are capable of generating addresses with a user-predefined pattern automatically at the speed of one address per clock cycle and operate at clock rates up to 80 MHz. They can operate concurrently with other processes and thus do not introduce additional operation latencies. Although we focus on applying the developed AGUs to executing 2D and 3D FFT, we expect that the modular design method should have much wider applications. PMID:27370457

  11. Modularized architecture of address generation units suitable for real-time processing MR data on an FPGA

    NASA Astrophysics Data System (ADS)

    Li, Limin; Wyrwicz, Alice M.

    2016-06-01

    In this paper, we describe a modular approach to the design of an Address Generation Unit (AGU). The approach consists of development of a generic Address Generation Core (AGC) as a basic building block and the construction of an AGU from the AGCs. We illustrate this concept with AGUs capable of handling 2D- and 3D-structured data, and as well as their setup for executing 2D and 3D FFT algorithms on a Field Programmable Gate Array (FPGA). The AGUs developed using our proposed method are simple and easily expandable. Furthermore, they can potentially support irregularly structured data which are often generated from the wide variety of pulse sequences in magnetic resonance imaging. Our experimental results show that these AGUs are capable of generating addresses with a user-predefined pattern automatically at the speed of one address per clock cycle and operate at clock rates up to 80 MHz. They can operate concurrently with other processes and thus do not introduce additional operation latencies. Although we focus on applying the developed AGUs to executing 2D and 3D FFT, we expect that the modular design method should have much wider applications.

  12. Gas-Generator Augmented Expander Cycle Rocket Engine

    NASA Technical Reports Server (NTRS)

    Greene, William D. (Inventor)

    2011-01-01

    An augmented expander cycle rocket engine includes first and second turbopumps for respectively pumping fuel and oxidizer. A gas-generator receives a first portion of fuel output from the first turbopump and a first portion of oxidizer output from the second turbopump to ignite and discharge heated gas. A heat exchanger close-coupled to the gas-generator receives in a first conduit the discharged heated gas, and transfers heat to an adjacent second conduit carrying fuel exiting the cooling passages of a primary combustion chamber. Heat is transferred to the fuel passing through the cooling passages. The heated fuel enters the second conduit of the heat exchanger to absorb more heat from the first conduit, and then flows to drive a turbine of one or both of the turbopumps. The arrangement prevents the turbopumps exposure to combusted gas that could freeze in the turbomachinery and cause catastrophic failure upon attempted engine restart.

  13. Landfill gas generation after mechanical biological treatment of municipal solid waste. Estimation of gas generation rate constants.

    PubMed

    Gioannis, G De; Muntoni, A; Cappai, G; Milia, S

    2009-03-01

    Mechanical biological treatment (MBT) of residual municipal solid waste (RMSW) was investigated with respect to landfill gas generation. Mechanically treated RMSW was sampled at a full-scale plant and aerobically stabilized for 8 and 15 weeks. Anaerobic tests were performed on the aerobically treated waste (MBTW) in order to estimate the gas generation rate constants (k,y(-1)), the potential gas generation capacity (L(o), Nl/kg) and the amount of gasifiable organic carbon. Experimental results show how MBT allowed for a reduction of the non-methanogenic phase and of the landfill gas generation potential by, respectively, 67% and 83% (8 weeks treatment), 82% and 91% (15 weeks treatment), compared to the raw waste. The amount of gasified organic carbon after 8 weeks and 15 weeks of treatment was equal to 11.01+/-1.25kgC/t(MBTW) and 4.54+/-0.87kgC/t(MBTW), respectively, that is 81% and 93% less than the amount gasified from the raw waste. The values of gas generation rate constants obtained for MBTW anaerobic degradation (0.0347-0.0803y(-1)) resemble those usually reported for the slowly and moderately degradable fractions of raw MSW. Simulations performed using a prediction model support the hypothesis that due to the low production rate, gas production from MBTW landfills is well-suited to a passive management strategy. PMID:18954969

  14. Design and Experimental Evaluation of a 3rd Generation Addressable CMOS Piezoresistive Stress Sensing Test Chip

    SciTech Connect

    Sweet, J.N.; Peterson, D.W.; Hsia, A.H.

    1999-04-13

    Piezoresistive stress sensing chips have been used extensively for measurement of assembly related die surface stresses. Although many experiments can be performed with resistive structures which are directly bonded, for extensive stress mapping it is necessary to have a large number of sensor cells which can be addressed using CMOS logic circuitry. Our previous test chip, the ATC04, has 100 cells, each approximately 0.012 in. on a side, on a chip with a side dimension of 0.45 in. When a cell resistor is addressed, it is connected to a four terminal measurement bus through CMOS transmission gates. In theory, the gate resistances do not affect the measurement. In practice, there may be subtle effects which appear when very high accuracy is required. At high temperatures, gate leakage can increase to a point at which the resistor measurement becomes inaccurate. For ATC04 this occurred at or above 50 C. Here, we report on the first measurements obtained with a new prototype test chip, the ATC06. This prototype was fabricated in a 0.5 micron feature size silicided CMOS process using the MOSIS prototyping facility. The cell size was approximately 0.004 in. on a side. In order to achieve piezoresistive behavior for the implanted resistors it was necessary to employ a non-standard silicide ''blocking'' process. The stress sensitivity of both implanted and polysilicon blocked resistors is discussed. Using a new design strategy for the CMOS logic, it was possible to achieve a design in which only 5 signals had to be routed to a cell for addressing vs. 9 for ATC04. With our new design, the resistor under test is more effectively electrically isolated from other resistors on the chip, thereby improving high temperature performance. We present data showing operation up to 140 C.

  15. Next-generation clinical trials: Novel strategies to address the challenge of tumor molecular heterogeneity

    PubMed Central

    Catenacci, Daniel V.T.

    2014-01-01

    The promise of ‘personalized cancer care’ with therapies toward specific molecular aberrations has potential to improve outcomes. However, there is recognized heterogeneity within any given tumor-type from patient to patient (inter-patient heterogeneity), and within an individual (intra-patient heterogeneity) as demonstrated by molecular evolution through space (primary tumor to metastasis) and time (after therapy). These issues have become hurdles to advancing cancer treatment outcomes with novel molecularly targeted agents. Classic trial design paradigms are challenged by heterogeneity, as they are unable to test targeted therapeutics against low frequency genomic ‘oncogenic driver’ aberrations with adequate power. Usual accrual difficulties to clinical trials are exacerbated by low frequencies of any given molecular driver. To address these challenges, there is need for innovative clinical trial designs and strategies implementing novel diagnostic biomarker technologies to account for inter-patient molecular diversity and scarce tissue for analysis. Importantly, there is also need for pre-defined treatment priority algorithms given numerous aberrations commonly observed within any one individual sample. Access to multiple available therapeutic agents simultaneously is crucial. Finally intra-patient heterogeneity through time may be addressed by serial biomarker assessment at the time of tumor progression. This report discusses various ‘next-generation’ biomarker-driven trial designs and their potentials and limitations to tackle these recognized molecular heterogeneity challenges. Regulatory hurdles, with respect to drug and companion diagnostic development and approval, are considered. Focus is on the ‘Expansion Platform Design Types I and II’, the latter demonstrated with a first example, ‘PANGEA: Personalized Anti-Neoplastics for Gastro-Esophageal Adenocarcinoma’. Applying integral medium-throughput genomic and proteomic assays along with

  16. Sand control in wells with gas generator and resin

    SciTech Connect

    Dees, J.M.

    1992-04-07

    This patent describes a method of treating a wellbore having formation perforations for controlling sand and other fine materials. It comprises positioning a quantity of fluid resin material in alignment with the formation perforations of the wellbore; positioning a gas generator in proximity with the fluid resin material; actuating the gas generator to increase wellbore pressure in a substantially instantaneous manner to a pressure substantially in excess of well pressure to force the fluid resin material from the wellbore into the formation perforations; and subsequently polymerizing the resin material to form a consolidated, porous, permeable matrix which retains the sand and other fine materials while permitting the flow of production fluid into the wellbore. This paper also describes a method of treating a wellbore having formation perforations for controlling sand and other fine materials. It comprises positioning a coiled tubing, having a valve and gas generator attached thereto, so that the valve is positioned in a predetermined location relative to the bottom formation perforation; injecting a predetermined amount of fluid resin material through the coiled tubing and valve into the wellbore; raising the gas generator to a position across the formation perforations and in proximity with the fluid resin material; actuating the gas generator to force the fluid resin material into the formation perforations; and thereafter polymerizing the previously fluid resin material to form a consolidated, porous, permeable matrix which retains the sand and other fine materials while permitting the flow of production fluid into the wellbore.

  17. Addressing Next Generation Science Standards: A Method for Supporting Classroom Teachers

    ERIC Educational Resources Information Center

    Pellien, Tamara; Rothenburger, Lisa

    2014-01-01

    The Next Generation Science Standards (NGSS) will define science education for the foreseeable future, yet many educators struggle to see the bridge between current practice and future practices. The inquiry-based methods used by Extension professionals (Kress, 2006) can serve as a guide for classroom educators. Described herein is a method of…

  18. Internet Addressing: The Next Generation. Why It's Changing and Why Librarians Should Care.

    ERIC Educational Resources Information Center

    Wakefield, Kate

    1997-01-01

    Revisions to Internet standards, the Next Generation Internet Protocol (IPng), will be tested with initiatives such as Internet II, a high-speed Internet being developed by a consortium of universities, and the vBNS, a National Science Foundation and MCI project. Argues that librarians should be aware of these changes if they want to participate…

  19. Assessing climate benefits of natural gas and coal electricity generation

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaochun; Myhrvold, Nathan; Caldeira, Ken

    2015-04-01

    A transition from a system of coal electricity generation to near-zero emission electricity generation will be central to any effort to mitigate climate change. Natural gas is increasingly seen as a 'bridge fuel' for transitions form coal to near-zero emission energy sources. However, various studies use different metrics to estimate the climate impact of natural gas utilization, and led to differing conclusions. Thus, there is a need to identify the key factors affecting the climate effects of natural gas and coal electricity production, and to present these climate effects in as clear and transparent a way as possible. Here, we identify power plant efficiency and methane leakage rate as the key factors that explain most of the variance in greenhouse gas emissions by natural gas and coal power plants. We then develop a power plant GHG emission model, apply available life-cycle parameters to calculate associated CO2 and CH4 emissions and assess climate effects. Simple underlying physical changes can be obscured by abstract evaluation metrics, thus we base our discussion on temperature changes over time. We find that, during the period of plant operation, if there is substantial natural gas leakage, natural gas plants can produce greater near-term warming than a coal plant with the same power output. If leakage rates can be made to be low and efficiency high, natural gas plants can produce some reduction in near-term warming. However, without carbon capture and storage natural gas power plants cannot achieve the deep reductions that would be required to avoid substantial contribution to additional global warming. Achieving climate benefits from the use of natural gas depends on building high-efficiency natural gas plants, controlling methane leakage, and on developing a policy environment that assures a transition to future lower-emission technologies. For more information please see http://iopscience.iop.org/1748-9326/9/11/114022/article .

  20. SHAPING A NEW GENERATION OF HISPANIC CLINICAL AND TRANSLATIONAL RESEARCHERS ADDRESSING MINORITY HEALTH AND HEALTH DISPARITIES

    PubMed Central

    Estape, Estela S.; Segarra, Barbara; Baez, Adriana; Huertas, Aracelis; Diaz, Clemente; Frontera, Walter

    2012-01-01

    In 2011, research educators face significant challenges. Training programs in Clinical and Translational Research need to develop or enhance their curriculum to comply with new scientific trends and government policies. Curricula must impart the skills and competencies needed to help facilitate the dissemination and transfer of scientific advances at a faster pace than current health policy and practice. Clinical and translational researchers are facing also the need of new paradigms for effective collaboration, and resource sharing while using the best educational models. Both government and public policy makers emphasize addressing the goals of improving health quality and elimination of health disparities. To help achieve this goal, our academic institution is taking an active role and striving to develop an environment that fosters the career development of clinical and translational researchers. Consonant with this vision, in 2002 the University of Puerto Rico, Medical Sciences Campus School of Health Professions and School of Medicine initiated a multidisciplinary post-doctoral Master of Science in Clinical Research focused in training Hispanics who will address minority health and health disparities research. Recently, we proposed a curriculum revision to enhance this commitment in promoting competency-based curricula for clinician-scientists in clinical and translational sciences. The revised program will be a post-doctoral Master of Science in Clinical and Translational Research (MCTR), expanding its outreach by actively engaging in establishing new collaborations and partnerships that will increase our capability to diversify our educational efforts and make significant contributions to help reduce and eliminate the gap in health disparities. PMID:22263296

  1. A design of three-stage addressing sweep frequency signal generator

    NASA Astrophysics Data System (ADS)

    Liu, Zhihui; Fan, Muwen; Zhou, Luchun

    2015-10-01

    In order to test the working state of adaptive optics system, it is necessary to design an online sweep-frequency circuit module to test the frequency response of the adaptive system. Sweep-frequency signal generator based on Direct Digital frequency Synthesis (DDS) is one of the core components. But the classic DDS technology also has some drawbacks: the truncation error of phase, the truncation error of magnitude (caused by memory FWL) and high occupancy of ROM. These are also the optimization directions in this paper. This paper presents a FPGA-based DDS sweep-frequency signal generator suitable in adaptive optics. It has a low occupancy rate with ROM. And in the case of low-ROM, the paper reduces the noise generated by the truncation error of phase and the truncation error of magnitude of DDS sweepfrequency signal generator by method of linear interpolation. The results show that, when the reference frequency is 100 MHz, the frequency resolution can be as low as 0.025 Hz. It only takes up 0.5 KB ROM with the ROM compression ratio of 64:1 in the optimized scheme in the paper and has higher precision due to the method of linear interpolation than the unoptimized scheme, which can meet the engineering needs. Compared with other schemes, the scheme in the paper improves signal accuracy in the case of reducing the truncation error of phase, the truncation error of magnitude and the occupancy rate with ROM, but only adds a multiplication and division circuit, which is a practical solution.

  2. High order harmonic generation in dual gas multi-jets

    SciTech Connect

    Tosa, Valer E-mail: calin.hojbota@itim-cj.ro; Hojbota, Calin E-mail: calin.hojbota@itim-cj.ro

    2013-11-13

    High order harmonic generation (HHG) in gas media suffers from a low conversion efficiency that has its origins in the interaction of the atom/molecule with the laser field. Phase matching is the main way to enhance the harmonic flux and several solutions have been designed to achieve it. Here we present numerical results modeling HHG in a system of multi-jets in which two gases alternate: the first gas jet (for example Ne) generates harmonics and the second one which ionizes easier, recover the phase matching condition. We obtain configurations which are experimentally feasible with respect to pressures and dimensions of the jets.

  3. Hybrid propulsion based on fluid-controlled solid gas generators

    NASA Technical Reports Server (NTRS)

    Cohen, Norman S.; Strand, Leon D.

    1993-01-01

    The use of fuel-rich solid (gas generator-type) propellants for hybrid propulsion affords some design and utilization efficiency advantages. Both forward and aft liquid injection control concepts are evaluated from the operational standpoints of ballistics, throttling, stability and extinguishment. Steady-state and non-steady ballistics analyses are employed for this evaluation. Stability of solid motor operation is enhanced by fluid injection with adequate injector pressure drop. Efficient throttling and reliable extinguishment are attained through a combination of solid propellant combustion tailoring, grain design, control valves and sensors. Initial results from a laboratory-scale slab combustor, combining a gas generator propellant with gaseous oxygen injection, are also presented.

  4. Tempest: Tools for Addressing the Needs of Next-Generation Climate Models

    NASA Astrophysics Data System (ADS)

    Ullrich, P. A.; Guerra, J. E.; Pinheiro, M. C.; Fong, J.

    2015-12-01

    Tempest is a comprehensive simulation-to-science infrastructure that tackles the needs of next-generation, high-resolution, data intensive climate modeling activities. This project incorporates three key components: TempestDynamics, a global modeling framework for experimental numerical methods and high-performance computing; TempestRemap, a toolset for arbitrary-order conservative and consistent remapping between unstructured grids; and TempestExtremes, a suite of detection and characterization tools for identifying weather extremes in large climate datasets. In this presentation, the latest advances with the implementation of this framework will be discussed, and a number of projects now utilizing these tools will be featured.

  5. Biomass & Natural Gas Based Hydrogen Fuel For Gas Turbine (Power Generation)

    EPA Science Inventory

    Significant progress has been made by major power generation equipment manufacturers in the development of market applications for hydrogen fuel use in gas turbines in recent years. Development of a new application using gas turbines for significant reduction of power plant CO2 e...

  6. Addressing information management and dissemination challenges for the next generation analyst

    NASA Astrophysics Data System (ADS)

    Kovach, Jesse; Sadler, Laurel; Suri, Niranjan; Winkler, Robert

    2015-05-01

    Recent technological advances in the areas of sensors, computation, and storage have led to the development of relatively inexpensive sensors that have been deployed on a wide scale and are able to generate large volumes of data. However, tactical networks have not been able to keep pace in terms of their ability to transfer all of the sensor data from the edge to an operations center for analysis. This paper explores multiple techniques to help bridge this gap, by using a three-pronged approach based on value of information-based dissemination, active sensor query capabilities, and anomaly detection mechanisms. These capabilities are being integrated into an open-source sensor platform deployed in a testbed environment for evaluation purposes.

  7. Harmonization of Initial Estimates of Shale Gas Life Cycle Greenhouse Gas Emissions for Electric Power Generation

    NASA Astrophysics Data System (ADS)

    Heath, G.; O'Donoughue, P.; Arent, D.; Bazilian, M.

    2014-12-01

    Recent technological advances in the recovery of unconventional natural gas, particularly shale gas, have served to dramatically increase domestic production and reserve estimates for the United States and internationally. This trend has led to lowered prices and increased scrutiny on production practices. Questions have been raised as to how greenhouse gas (GHG) emissions from the life cycle of shale gas production and use compares with that of conventionally produced natural gas or other fuel sources such as coal. Recent literature has come to different conclusions on this point, largely due to differing assumptions, comparison baselines, and system boundaries. Through a meta-analytical procedure we call harmonization, we develop robust, analytically consistent, and updated comparisons of estimates of life cycle GHG emissions for electricity produced from shale gas, conventionally produced natural gas, and coal. On a per unit electrical output basis, harmonization reveals that median estimates of GHG emissions from shale gas-generated electricity are similar to those for conventional natural gas, with both approximately half that of the central tendency of coal. Sensitivity analysis on the harmonized estimates indicates that assumptions regarding liquids unloading and estimated ultimate recovery (EUR) of wells have the greatest influence on life cycle GHG emissions, whereby shale gas life cycle GHG emissions could approach the range of best performing coal-fired generation under certain scenarios. Despite clarification of published estimates through harmonization, these initial assessments should be confirmed through methane emissions measurements at components and in the atmosphere and through better characterization of EUR and practices.

  8. Spent Nuclear Fuel Project (SNFP) gas generation from N-Fuel in multi-canister overpacks

    SciTech Connect

    Cooper, T.D.

    1996-08-01

    During the conversion from wet pool storage for spent nuclear fuel at Hanford, gases will be generated from both radiolysis and chemical reactions. The gas generation phenomenon needs to be understood as it applies to safety and design issues,specifically over pressurization of sealed storage containers,and detonation/deflagration of flammable gases. This study provides an initial basis to predict the implications of gas generation on the proposed functional processes for spent nuclear fuel conversion from wet to dry storage. These projections are based upon examination of the history of fuel manufacture at Hanford, irradiation in the reactors, corrosion during wet pool storage, available fuel characterization data and available information from literature. Gas generation via radiolysis and metal corrosion are addressed. The study examines gas generation, the boundary conditions for low medium and high levels of sludge in SNF storage/processing containers. The functional areas examined include: flooded and drained Multi-Canister Overpacks, cold vacuum drying, shipping and staging and long term storage.

  9. Gas Generation from K East Basin Sludges - Series II Testing

    SciTech Connect

    Bryan, Samuel A.; Delegard, Calvin H.; Schmidt, Andrew J.; Sell, Rachel L.; Silvers, Kurt L.; Gano, Susan R.; Thornton, Brenda M.

    2004-04-26

    This report describes work to examine the gas generation behavior of actual K East (KE) Basin floor, pit and canister sludge. Mixed and unmixed and fractionated KE canister sludge were tested, along with floor and pit sludges from areas in the KE Basin not previously sampled. The first report in this series focuses on gas generation from KE floor and canister sludge collected using a consolidated sampling technique. The third report presents results of gas generation testing of irradiated uranium fuel fragments with and without sludge addition. The path forward for management of the K Basin Sludge is to retrieve, ship, and store the sludge at T Plant until final processing at some future date. Gas generation will impact the designs and costs of systems associated with retrieval, transportation and storage of sludge. This report was originally published in March 2001. In January 2004, a transcription error was discovered in the value reported for the uranium metal content of KE North Loadout Pit sample FE-3. This revision of the report corrects the U metal content of FE-3 from 0.0013 wt% to 0.013 wt%.

  10. 33. Lower level, ballistic gas generator at left (opens launcher ...

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

    33. Lower level, ballistic gas generator at left (opens launcher door during launch), LDB panel at right - Ellsworth Air Force Base, Delta Flight, Launch Facility, On County Road T512, south of Exit 116 off I-90, Interior, Jackson County, SD

  11. Generating Apparatus for Gas Heat Pump System using Sensorless-Controlled Permanent Magnet Synchronous Generator

    NASA Astrophysics Data System (ADS)

    Toba, Akio; Fujita, Kouetsu; Maeda, Toshihiro; Kato, Tomohiko

    A unique generating system for Gas heat pump system (GHP) is presented. The GHP is an air-conditioning system, in which the compressors are driven by a gas engine. The proposed system is applied to the outside unit of GHP to feed the electrical equipments inside. The system utilizes a permanent magnet synchronous generator, which is connected to the gas engine, to realize high-efficiency and small-size. The generator is controlled by a converter with sensorless control technology to eliminate the position sensor. Another major topic is the “free-run startup" technique to start the converter when the generator is rotating. The system configuration and principles of the techniques are set forth, followed by experimental results which show that the system works properly and successfully.

  12. Durability Challenges for Next Generation of Gas Turbine Engine Materials

    NASA Technical Reports Server (NTRS)

    Misra, Ajay K.

    2012-01-01

    Aggressive fuel burn and carbon dioxide emission reduction goals for future gas turbine engines will require higher overall pressure ratio, and a significant increase in turbine inlet temperature. These goals can be achieved by increasing temperature capability of turbine engine hot section materials and decreasing weight of fan section of the engine. NASA is currently developing several advanced hot section materials for increasing temperature capability of future gas turbine engines. The materials of interest include ceramic matrix composites with 1482 - 1648 C temperature capability, advanced disk alloys with 815 C capability, and low conductivity thermal barrier coatings with erosion resistance. The presentation will provide an overview of durability challenges with emphasis on the environmental factors affecting durability for the next generation of gas turbine engine materials. The environmental factors include gaseous atmosphere in gas turbine engines, molten salt and glass deposits from airborne contaminants, impact from foreign object damage, and erosion from ingestion of small particles.

  13. Gas Generation from K East Basin Sludges - Series I Testing

    SciTech Connect

    Delegard, Calvin H.; Bryan, Samuel A.; Schmidt, Andrew J.; Bredt, Paul R.; King, Christopher M.; Sell, Rachel L.; Burger, Leland L.; Silvers, Kurt L.

    2000-09-12

    This report describes work to examine the gas generation behavior of actual K East (KE) Basin floor and canister sludge. The path forward for management of the K Basin Sludge is to retrieve, ship, and store the sludge at T Plant until final processing at some future date. Gas generation will impact the designs and costs of systems associated with retrieval, transportation and storage of sludge. The overall goals for this testing were to collect detailed gas generation rate and composition data to ascertain the quantity and reactivity of the metallic uranium (and other reactive species) present in the K Basin sludge. The gas generation evaluation included four large-scale vessels (850 ml) and eight small-scale vessels (30 ml) in an all-metal, leak tight system. The tests were conducted for several thousand hours at ambient and elevated temperatures (32 C, 40 C, 60 C, 80 C, and 95 C) to accelerated the reactions and provide conclusive gas generation data within a reasonable testing period. The sludge used for these tests was collected from the KE Basin floor and canister barrels (containing damaged spent fuel elements) using a consolidated sampling technique (i.e., material from several locations was combined to form ''consolidated samples''). Portions of these samples were sieved to separate particles greater than 250 m (P250) from particle less than 250 m (M250). This separation was performed to mimic the separation operations that are planned during the retrieval of certain K Basin sludge types and to gain a better understanding of how uranium metal is distributed in the sludge. The corrosion rate of the uranium metal particles in the sludge was found to agree reasonably well with corrosion rates reported in the literature.

  14. Revisions to the hydrogen gas generation computer model

    SciTech Connect

    Jerrell, J.W.

    1992-08-31

    Waste Management Technology has requested SRTC to maintain and extend a previously developed computer model, TRUGAS, which calculates hydrogen gas concentrations within the transuranic (TRU) waste drums. TRUGAS was written by Frank G. Smith using the BASIC language and is described in the report A Computer Model of gas Generation and Transport within TRU Waste Drums (DP- 1754). The computer model has been partially validated by yielding results similar to experimental data collected at SRL and LANL over a wide range of conditions. The model was created to provide the capability of predicting conditions that could potentially lead to the formation of flammable gas concentrations within drums, and to assess proposed drum venting methods. The model has served as a tool in determining how gas concentrations are affected by parameters such as filter vent sizes, waste composition, gas generation values, the number and types of enclosures, water instrusion into the drum, and curie loading. The success of the TRUGAS model has prompted an interest in the program`s maintenance and enhancement. Experimental data continues to be collected at various sites on such parameters as permeability values, packaging arrangements, filter designs, and waste contents. Information provided by this data is used to improve the accuracy of the model`s predictions. Also, several modifications to the model have been made to enlarge the scope of problems which can be analyzed. For instance, the model has been used to calculate hydrogen concentrations inside steel cabinets containing retired glove boxes (WSRC-RP-89-762). The revised TRUGAS computer model, H2GAS, is described in this report. This report summarizes all modifications made to the TRUGAS computer model and provides documentation useful for making future updates to H2GAS.

  15. Revisions to the hydrogen gas generation computer model

    SciTech Connect

    Jerrell, J.W.

    1992-08-31

    Waste Management Technology has requested SRTC to maintain and extend a previously developed computer model, TRUGAS, which calculates hydrogen gas concentrations within the transuranic (TRU) waste drums. TRUGAS was written by Frank G. Smith using the BASIC language and is described in the report A Computer Model of gas Generation and Transport within TRU Waste Drums (DP- 1754). The computer model has been partially validated by yielding results similar to experimental data collected at SRL and LANL over a wide range of conditions. The model was created to provide the capability of predicting conditions that could potentially lead to the formation of flammable gas concentrations within drums, and to assess proposed drum venting methods. The model has served as a tool in determining how gas concentrations are affected by parameters such as filter vent sizes, waste composition, gas generation values, the number and types of enclosures, water instrusion into the drum, and curie loading. The success of the TRUGAS model has prompted an interest in the program's maintenance and enhancement. Experimental data continues to be collected at various sites on such parameters as permeability values, packaging arrangements, filter designs, and waste contents. Information provided by this data is used to improve the accuracy of the model's predictions. Also, several modifications to the model have been made to enlarge the scope of problems which can be analyzed. For instance, the model has been used to calculate hydrogen concentrations inside steel cabinets containing retired glove boxes (WSRC-RP-89-762). The revised TRUGAS computer model, H2GAS, is described in this report. This report summarizes all modifications made to the TRUGAS computer model and provides documentation useful for making future updates to H2GAS.

  16. NASA Fastrac Engine Gas Generator Component Test Program and Results

    NASA Technical Reports Server (NTRS)

    Dennis, Henry J., Jr.; Sanders, Tim; Turner, James E. (Technical Monitor)

    2000-01-01

    This presentation consists of viewgraph which review the test program and the results of the tests for the Gas Generator (GG) component for the Fastrac Engine. Included are pictures of the Fastrac (MC-1) Engine and the GG, diagrams of the flight configuration, and schematics of the LOX, and the RP-1 systems and the injector assembly. The normal operating parameters are reviewed, as are the test instrumentation. Also shown are graphs of the hot gas temperature, and the test temperature profiles. The results are summarized.

  17. Addressable, large-field second harmonic generation microscopy based on 2D acousto-optical deflector and spatial light modulator

    PubMed Central

    Shao, Yonghong; Liu, Honghai; Qin, Wan; Qu, Junle; Peng, Xiang; Niu, Hanben

    2013-01-01

    We present an addressable, large-field second harmonic generation microscope by combining a 2D acousto-optical deflector with a spatial light modulator. The SLM shapes an incoming mode-locked, near-infrared Ti:Sapphire laser beam into a multifocus array, which can be rapidly scanned by changing the incident angle of the laser beam using a 2D acousto-optical deflector. Compared to the single-beam-scan technique, the multifocus array scan can increase the scanning rate and the field-of-view size with the multi-region imaging ability. PMID:24307756

  18. Modeling acid-gas generation from boiling chloride brines

    SciTech Connect

    Zhang, Guoxiang; Spycher, Nicolas; Sonnenthal, Eric; Steefel, Carl

    2009-11-16

    This study investigates the generation of HCl and other acid gases from boiling calcium chloride dominated waters at atmospheric pressure, primarily using numerical modeling. The main focus of this investigation relates to the long-term geologic disposal of nuclear waste at Yucca Mountain, Nevada, where pore waters around waste-emplacement tunnels are expected to undergo boiling and evaporative concentration as a result of the heat released by spent nuclear fuel. Processes that are modeled include boiling of highly concentrated solutions, gas transport, and gas condensation accompanied by the dissociation of acid gases, causing low-pH condensate. Simple calculations are first carried out to evaluate condensate pH as a function of HCl gas fugacity and condensed water fraction for a vapor equilibrated with saturated calcium chloride brine at 50-150 C and 1 bar. The distillation of a calcium-chloride-dominated brine is then simulated with a reactive transport model using a brine composition representative of partially evaporated calcium-rich pore waters at Yucca Mountain. Results show a significant increase in boiling temperature from evaporative concentration, as well as low pH in condensates, particularly for dynamic systems where partial condensation takes place, which result in enrichment of HCl in condensates. These results are in qualitative agreement with experimental data from other studies. The combination of reactive transport with multicomponent brine chemistry to study evaporation, boiling, and the potential for acid gas generation at the proposed Yucca Mountain repository is seen as an improvement relative to previously applied simpler batch evaporation models. This approach allows the evaluation of thermal, hydrological, and chemical (THC) processes in a coupled manner, and modeling of settings much more relevant to actual field conditions than the distillation experiment considered. The actual and modeled distillation experiments do not represent

  19. Modeling acid-gas generation from boiling chloride brines

    PubMed Central

    2009-01-01

    Background This study investigates the generation of HCl and other acid gases from boiling calcium chloride dominated waters at atmospheric pressure, primarily using numerical modeling. The main focus of this investigation relates to the long-term geologic disposal of nuclear waste at Yucca Mountain, Nevada, where pore waters around waste-emplacement tunnels are expected to undergo boiling and evaporative concentration as a result of the heat released by spent nuclear fuel. Processes that are modeled include boiling of highly concentrated solutions, gas transport, and gas condensation accompanied by the dissociation of acid gases, causing low-pH condensate. Results Simple calculations are first carried out to evaluate condensate pH as a function of HCl gas fugacity and condensed water fraction for a vapor equilibrated with saturated calcium chloride brine at 50-150°C and 1 bar. The distillation of a calcium-chloride-dominated brine is then simulated with a reactive transport model using a brine composition representative of partially evaporated calcium-rich pore waters at Yucca Mountain. Results show a significant increase in boiling temperature from evaporative concentration, as well as low pH in condensates, particularly for dynamic systems where partial condensation takes place, which result in enrichment of HCl in condensates. These results are in qualitative agreement with experimental data from other studies. Conclusion The combination of reactive transport with multicomponent brine chemistry to study evaporation, boiling, and the potential for acid gas generation at the proposed Yucca Mountain repository is seen as an improvement relative to previously applied simpler batch evaporation models. This approach allows the evaluation of thermal, hydrological, and chemical (THC) processes in a coupled manner, and modeling of settings much more relevant to actual field conditions than the distillation experiment considered. The actual and modeled distillation

  20. Harmonization of initial estimates of shale gas life cycle greenhouse gas emissions for electric power generation

    PubMed Central

    Heath, Garvin A.; O’Donoughue, Patrick; Arent, Douglas J.; Bazilian, Morgan

    2014-01-01

    Recent technological advances in the recovery of unconventional natural gas, particularly shale gas, have served to dramatically increase domestic production and reserve estimates for the United States and internationally. This trend has led to lowered prices and increased scrutiny on production practices. Questions have been raised as to how greenhouse gas (GHG) emissions from the life cycle of shale gas production and use compares with that of conventionally produced natural gas or other fuel sources such as coal. Recent literature has come to different conclusions on this point, largely due to differing assumptions, comparison baselines, and system boundaries. Through a meta-analytical procedure we call harmonization, we develop robust, analytically consistent, and updated comparisons of estimates of life cycle GHG emissions for electricity produced from shale gas, conventionally produced natural gas, and coal. On a per-unit electrical output basis, harmonization reveals that median estimates of GHG emissions from shale gas-generated electricity are similar to those for conventional natural gas, with both approximately half that of the central tendency of coal. Sensitivity analysis on the harmonized estimates indicates that assumptions regarding liquids unloading and estimated ultimate recovery (EUR) of wells have the greatest influence on life cycle GHG emissions, whereby shale gas life cycle GHG emissions could approach the range of best-performing coal-fired generation under certain scenarios. Despite clarification of published estimates through harmonization, these initial assessments should be confirmed through methane emissions measurements at components and in the atmosphere and through better characterization of EUR and practices. PMID:25049378

  1. Harmonization of initial estimates of shale gas life cycle greenhouse gas emissions for electric power generation.

    PubMed

    Heath, Garvin A; O'Donoughue, Patrick; Arent, Douglas J; Bazilian, Morgan

    2014-08-01

    Recent technological advances in the recovery of unconventional natural gas, particularly shale gas, have served to dramatically increase domestic production and reserve estimates for the United States and internationally. This trend has led to lowered prices and increased scrutiny on production practices. Questions have been raised as to how greenhouse gas (GHG) emissions from the life cycle of shale gas production and use compares with that of conventionally produced natural gas or other fuel sources such as coal. Recent literature has come to different conclusions on this point, largely due to differing assumptions, comparison baselines, and system boundaries. Through a meta-analytical procedure we call harmonization, we develop robust, analytically consistent, and updated comparisons of estimates of life cycle GHG emissions for electricity produced from shale gas, conventionally produced natural gas, and coal. On a per-unit electrical output basis, harmonization reveals that median estimates of GHG emissions from shale gas-generated electricity are similar to those for conventional natural gas, with both approximately half that of the central tendency of coal. Sensitivity analysis on the harmonized estimates indicates that assumptions regarding liquids unloading and estimated ultimate recovery (EUR) of wells have the greatest influence on life cycle GHG emissions, whereby shale gas life cycle GHG emissions could approach the range of best-performing coal-fired generation under certain scenarios. Despite clarification of published estimates through harmonization, these initial assessments should be confirmed through methane emissions measurements at components and in the atmosphere and through better characterization of EUR and practices. PMID:25049378

  2. Gas generation and gas migration in deep geological repositories for radioactive waste

    SciTech Connect

    Haijtink, B.

    1996-12-31

    It is generally accepted that there will be some degree of gas generation in deep geological repositories for radioactive waste. This gas generation will depend on a number of factors such as the nature of the waste, the waste container, the buffer material and the near field host rock. In an ideal situation the gas generated would all dissolve in the groundwater and/or be transported away from the deep repository by the mechanisms of advection, diffusion and dispersion. However the sought-after characteristic of a repository host medium of very low permeability, e.g. bentonite buffer material and argillaceous geological media can be problematic when considering gas migration. High gas pressures might be build-up which could lead to potential fracturing of engineered barriers in the near field and enhancing groundwater flow and radionuclide migration. Various theoretical as well as experimental research activities have been undertaken to investigate the different phenomena. Within the framework of R&D programmes on Management and Storage of Radioactive Waste, conducted by the European Commission, some of the research activities are grouped together in a coordinated project named PEGASUS (Project on the Effects of GAS in an Underground Storage facility). In this project a total of about twenty research institutes and laboratories from seven different European countries are involved. This PEGASUS project will be followed up by a new project named PROGRESS (PROject of Research into Gas generation and migration in radioactive waste REpository SystemS). In this paper, an overview is given of the various research activities carried out and results obtained so far.

  3. 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.

  4. Effects of oxygen cover gas and NaOH dilution on gas generation in tank 241-SY-101 waste

    SciTech Connect

    Person, J.C.

    1996-05-30

    Laboratory studies are reported of gas generation in heated waste from tank 241-SY-101. The rates of gas generation and the compositions of product gas were measured. Three types of tests are compared. The tests use: undiluted waste, waste diluted by a 54% addition of 2.5 M NaOH, and undiluted waste with a reactive cover gas of 30% Oxygen in He. The gas generation rate is reduced by dilution, increased by higher temperatures (which determines activation energies), and increased by reactions of Oxygen (these primarily produce H{sub 2}). Gases are generated as reduction products oxidation of organic carbon species by nitrite and oxygen.

  5. Increased capability gas generator for Space Shuttle APU. Development/hot restart test report

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The design, fabrication, and testing of an increased capability gas generator for use in space shuttles are described. Results show an unlimited hot restart capability in the range of feed pressures from 400 psi to 80 psi. Effects of vacuum on hot restart were not addressed, and only beginning-of-life bed conditions were tested. No starts with bubbles were performed. A minimum expected life of 35 hours or more is projected, and the design will maintain a surface temperature of 350 F or more.

  6. Method of generating hydrogen gas from sodium borohydride

    DOEpatents

    Kravitz, Stanley H.; Hecht, Andrew M.; Sylwester, Alan P.; Bell, Nelson S.

    2007-12-11

    A compact solid source of hydrogen gas, where the gas is generated by contacting water with micro-disperse particles of sodium borohydride in the presence of a catalyst, such as cobalt or ruthenium. The micro-disperse particles can have a substantially uniform diameter of 1-10 microns, and preferably about 3-5 microns. Ruthenium or cobalt catalytic nanoparticles can be incorporated in the micro-disperse particles of sodium borohydride, which allows a rapid and complete reaction to occur without the problems associated with caking and scaling of the surface by the reactant product sodium metaborate. A closed loop water management system can be used to recycle wastewater from a PEM fuel cell to supply water for reacting with the micro-disperse particles of sodium borohydride in a compact hydrogen gas generator. Capillary forces can wick water from a water reservoir into a packed bed of micro-disperse fuel particles, eliminating the need for using an active pump.

  7. Leakage Currents and Gas Generation in Advanced Wet Tantalum Capacitors

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2015-01-01

    Currently, military grade, established reliability wet tantalum capacitors are among the most reliable parts used for space applications. This has been achieved over the years by extensive testing and improvements in design and materials. However, a rapid insertion of new types of advanced, high volumetric efficiency capacitors in space systems without proper testing and analysis of degradation mechanisms might increase risks of failures. The specifics of leakage currents in wet electrolytic capacitors is that the conduction process is associated with electrolysis of electrolyte and gas generation resulting in building up of internal gas pressure in the parts. The risk associated with excessive leakage currents and increased pressure is greater for high value advanced wet tantalum capacitors, but it has not been properly evaluated yet. In this work, in Part I, leakages currents in various types of tantalum capacitors have been analyzed in a wide range of voltages, temperatures, and time under bias. Gas generation and the level of internal pressure have been calculated in Part II for different case sizes and different hermeticity leak rates to assess maximal allowable leakage currents. Effects related to electrolyte penetration to the glass seal area have been studied and the possibility of failures analyzed in Part III. Recommendations for screening and qualification to reduce risks of failures have been suggested.

  8. Generation and characterization of gas bubbles in liquid metals

    SciTech Connect

    Eckert, S.; Gerbeth, G.; Witke, W.

    1996-06-01

    There is an ongoing research performed in the RCR on local transport phenomena in turbulent liquid metal (LM) duct flows exposed to external magnetic fields. In this context so-called MHD flow phenomena can be observed, which are unknown in usual hydraulic engineering. The field of interest covers also the influence of magnetic fields on the behaviour of liquid metal - gas mixtures. Profound knowledge on these LMMHD two-phase flow plays an important role in a variety of technological applications, in particular, in the design of Liquid-Metal MHD generators or for several metallurgical processes employing gas-stirred reactors. However, the highly empirical nature of two-phase flow analysis gives little hope for the prediction of MHD two-phase flows without extensive experimental data. A summary is given about the authors research activities focussing on two directions: (a) Momentum transfer between gas and liquid metal in a bubbly flow regime to investigate the influence of the external magnetic field on the velocity slip ration S (b) Peculiarities of the MHD turbulence to use small gas bubbles as local tracers in order to study the turbulent mass transfer.

  9. Department of Energy power generation programs for natural gas

    SciTech Connect

    Bajura, R.A.

    1995-04-01

    The U.S. Department of Energy (DOE) is sponsoring two major programs to develop high efficiency, natural gas fueled power generation technologies. These programs are the Advanced Turbine Systems (ATS) Program and the Fuel Cell Program. While natural gas is gaining acceptance in the electric power sector, the improved technology from these programs will make gas an even more attractive fuel, particularly in urban areas where environmental concerns are greatest. Under the auspices of DOE`s Office of Fossil Energy (DOE/FE) and Office of Energy Efficiency and Renewable Energy (DOE/EE), the 8-year ATS Program is developing and will demonstrate advanced gas turbine power systems for both large central power systems and smaller industrial-scale systems. The large-scale systems will have efficiencies significantly greater than 60 percent, while the industrial-scale systems will have efficiencies with at least an equivalent 15 percent increase over the best 1992-vintage technology. The goal is to have the system ready for commercial offering by the year 2000.

  10. Inhomogeneous feed gas processing in industrial ozone generation.

    PubMed

    Krogh, Fabio; Merz, Reto; Gisler, Rudolf; Müller, Marco; Paolini, Bernhard; Lopez, Jose L; Freilich, Alfred

    2008-01-01

    The synthesis of ozone by means of dielectric barrier discharge (DBD) is extensively used in industry. Ozone generators available on the market differ in ozone production capacities, electrode arrangements and working parameters, but operate with a uniformly distributed filamentary discharge plasma pattern.In the presented work the benefits of inhomogeneous feed gas processing are explored. Causality between power induction, production efficiency and working parameters are investigated. Different electrode arrangements, evenly distributed within a given space parameter, were designed, simulated, manufactured and tested on a representative scale. A finite element model was utilized to simulate an inhomogeneous power induction pattern along the ozone generator tube. The simulation yielded the local power density, the local gas temperature gradient and the relative DBD packing density.Results show that the degree of filamentation turns out to be decisive, indicating a new potential by means of plasma tailoring. An arrangement with a pronounced power induction at the inlet of the ozone generator revealed several advantages over homogeneous plasma processing arrangements, for which an increase in robustness and a reduction in electrical power consumption are achieved. PMID:19092182

  11. Mitigation/remediation concepts for Hanford Site flammable gas generating waste tanks

    SciTech Connect

    Babad, H.; Deichman, J.L.; Johnson, B.M.; Lemon, D.K.; Strachan, D.M.

    1992-04-01

    This report presents a preliminary assessment of concepts for the mitigation and/or remediation of the hydrogen gas generation, storage, and periodic release in Tank 241-SY-101 (101-SY) and 22 other tanks. The 22 other tanks exhibit much less hydrogen generation (volume and concentration of released flammable gases) than Tank 101-SY and have not had the focus nor attention that has been given to Tank 101-SY. These tanks have been listed as potential hydrogen gas-generating tanks from analysis of tank performance and data from flowsheets and Track Radioactive Constituents Reports (TRAC). These lesser hydrogen-generating tanks will also need to be revisited and revalidated. Of the 23 hydrogen class tanks, 5 are double-shell tanks (DST) and 18 are single-shell tanks (SST). Options for mitigation or remediation are different for the two types of tanks because of age, configuration, and waste form. While this document principally focuses on Tank 101-SY, the information presented has been useful to address other tanks containing hydrogen-generating waste.

  12. Combustion Stability Analyses for J-2X Gas Generator Development

    NASA Technical Reports Server (NTRS)

    Hulka, J. R.; Protz, C. S.; Casiano, M. J.; Kenny, R. J.

    2010-01-01

    The National Aeronautics and Space Administration (NASA) is developing a liquid oxygen/liquid hydrogen rocket engine for upper stage and trans-lunar applications of the Ares vehicles for the Constellation program. This engine, designated the J-2X, is a higher pressure, higher thrust variant of the Apollo-era J-2 engine. Development was contracted to Pratt & Whitney Rocketdyne in 2006. Over the past several years, development of the gas generator for the J-2X engine has progressed through a variety of workhorse injector, chamber, and feed system configurations. Several of these configurations have resulted in injection-coupled combustion instability of the gas generator assembly at the first longitudinal mode of the combustion chamber. In this paper, the longitudinal mode combustion instabilities observed on the workhorse test stand are discussed in detail. Aspects of this combustion instability have been modeled at the NASA Marshall Space Flight Center with several codes, including the Rocket Combustor Interaction Design and Analysis (ROCCID) code and a new lumped-parameter MatLab model. To accurately predict the instability characteristics of all the chamber and injector geometries and test conditions, several features of the submodels in the ROCCID suite of calculations required modification. Finite-element analyses were conducted of several complicated combustion chamber geometries to determine how to model and anchor the chamber response in ROCCID. A large suite of sensitivity calculations were conducted to determine how to model and anchor the injector response in ROCCID. These modifications and their ramification for future stability analyses of this type are discussed in detail. The lumped-parameter MatLab model of the gas generator assembly was created as an alternative calculation to the ROCCID methodology. This paper also describes this model and the stability calculations.

  13. Study of compressor systems for a gas-generator engine

    NASA Technical Reports Server (NTRS)

    Sather, Bernard I; Tauschek, Max J

    1950-01-01

    Various methods of providing compressor-capacity and pressure-ratio control in the gas-generator type of compound engine over a range of altitudes from sea level to 50,000 feet are presented. The analytical results indicate that the best method of control is that in which the first stage of compression is carried out in a variable-speed supercharger driven by a hydraulic slip coupling. The constant-speed second stage could be either a mixed-flow rotary compressor or a piston-type compressor. A variable-area turbine nozzle is shown to be unnecessary for cruising operation of the engine.

  14. Gas generation in pure and impure plutonium-bearing materials

    SciTech Connect

    Mason, R.; Allen, T.; Eller, P.G.; Hagan, R.; Horrell, D.; Rink, N.

    1999-07-01

    The Los Alamos National Laboratory's (LANL's) materials identification and surveillance (MIS) project identifies materials to be stored in DOE-STD-3013-96 containers, determines the chemical and physical character of stored materials, and evaluates processing to be used to stabilize materials to meet the standard. The project has completed processing and analysis of 9 Hanford items and 24 Rocky Flats items, representing a substantial portion of the oxides to be packaged for long-term storage. The resultant data provide insight into the physical and chemical characteristics of the materials at the sites. A component of the study was to investigate gas generation for representative materials. These studies included headspace gas measurements over the 9 Hanford items, measurement of gas generation in 10-g surveillance samples of MIS powders, and pressure monitoring. Before examining the Hanford cans, sampling and analysis methods were demonstrated on HRA-905191, an item from the LANL vault. This item was not typical of materials designated to be stored in 3013 cans, as it contained plastic vials, emery cloths, paper towels, and a large percentage of thorium. However, it was one of the items that contained significant hydrogen in the headspace. A mass spectrometer was used to determine the composition of headspace gases. Oxygen was substantially depleted in all cases, and the percent of nitrogen in many items was greater than that found in air. In both cans with a high hydrogen content, the corresponding oxygen content was near zero (HRA905191 and ARF-102-85-365). In some cases, carbon dioxide was generated in the cans. Carbon monoxide was found in item BLO-39-11-85-295. This item has a high americium content, thus higher temperature than other materials examined. The only notable impurities in item BLO-39-11-85-295 were carbon at {approximately}0.1 wt% and chlorides at 0.2 wt%. Seven long-term surveillance vessels each holding {approximately}10 g of MIS powders have

  15. New-generation diesel fuel from coal, natural gas, and other carbonaceous feedstocks

    SciTech Connect

    Winslow, J.C.; Venkataraman, V.K.; Driscoll, D.J.; Nowak, M.; Srivastava, R.D.

    1999-07-01

    The U.S. economic security will continue to be vitally linked to an efficient transportation system of air, rail, and highway vehicles that depend on a continuous supply of liquid fuels at a reasonable price and with characteristics that can help vehicle manufacturers meet increasingly strict environmental regulations. This market offers an important opportunity to improve efficiency and lower emissions. One element of an overall strategy to address this energy security issue and help meet emissions requirements is to produce, via Fischer-Tropsch (F-T) and other synthesis-gas conversion technologies, premium transportation fuels from non-petroleum feedstocks, such as coal, natural gas, and biomass. Significant advances have been, and are continuing to be made, in F-T technology development to achieve the performance and cost targets necessary for commercial deployment. The key drivers, which form the basis for this paper, include capital cost reduction, efficiency improvements, energy optimization, and exploitation of novel, high-quality products generated by the F-T conversion process. The paper discusses the development of the slurry bubble column reactor (SBCR), a critical activity that has led to the successful demonstration of methanol production from coal-derived synthesis gas at Eastman Chemical Company's Kingsport, Tennessee, facilities. Research and development currently in place is building on this success in order to apply the SBCR technology to the production of other high value fuels and fuel additives. A concept for the efficient use of coal and natural gas to coproduce electric power and high quality liquid transportation fuels in one integrated facility has also been proposed. In addition, the development of novel ceramic membrane reactor systems for conversion of natural gas to synthesis gas will be discussed. This novel process holds the potential for reducing the cost of synthesis gas production from natural gas by 25% to 50% over current the

  16. Attosecond pulses generated by the lighthouse effect in Ar gas

    NASA Astrophysics Data System (ADS)

    Tosa, Valer; Lee, Ji Su; Kim, Hyung Taek; Nam, Chang Hee

    2015-05-01

    We numerically investigate harmonic generation in Ar gas under high ionization conditions and demonstrate that a lighthouse effect is present. We examine the structure of the driving field during propagation in temporal, spectral, and spatial domains, and conclude that the complete depletion of neutral Ar on axis gives rise to additional wavelets at off-axis regions. We show that these wavelets propagate with increasing divergence as the radial distances from the axis increase, generating the rotation of the wave front, thus fulfilling a necessary condition for the lighthouse effect. We obtain attosecond bursts of light emitted with different divergences in successive optical half-cycles so that in the far field these bursts arrive at different distances from the beam axis.

  17. Design optimization of gas generator hybrid propulsion boosters

    NASA Technical Reports Server (NTRS)

    Weldon, Vincent; Phillips, Dwight U.; Fink, Lawrence E.

    1990-01-01

    A methodology used in support of a contract study for NASA/MSFC to optimize the design of gas generator hybrid propulsion booster for uprating the National Space Transportation System (NSTS) is presented. The objective was to compare alternative configurations for this booster approach, optimizing each candidate concept on different bases, in order to develop data for a trade table on which a final decision was based. The methodology is capable of processing a large number of independent and dependent variables, adjusting the overall subsystems characteristics to arrive at a best compromise integrated design to meet various specified optimization criteria subject to selected constraints. For each system considered, a detailed weight statement was generated along with preliminary cost and reliability estimates.

  18. Design Optimization of Gas Generator Hybrid Propulsion Boosters

    NASA Technical Reports Server (NTRS)

    Weldon, Vincent; Phillips, Dwight; Fink, Larry

    1990-01-01

    A methodology used in support of a study for NASA/MSFC to optimize the design of gas generator hybrid propulsion booster for uprating the National Space Transportation System (NSTS) is presented. The objective was to compare alternative configurations for this booster approach, optimizing each candidate concept on different bases, in order to develop data for a trade table on which a final decision was based. The methodology is capable of processing a large number of independent and dependent variables, adjusting the overall subsystems characteristics to arrive at a best compromise integrated design to meet various specific optimization criteria subject to selected constraints. For each system considered, a detailed weight statement was generated along with preliminary cost and reliability estimates.

  19. Advanced Combustion Systems for Next Generation Gas Turbines

    SciTech Connect

    Joel Haynes; Jonathan Janssen; Craig Russell; Marcus Huffman

    2006-01-01

    Next generation turbine power plants will require high efficiency gas turbines with higher pressure ratios and turbine inlet temperatures than currently available. These increases in gas turbine cycle conditions will tend to increase NOx emissions. As the desire for higher efficiency drives pressure ratios and turbine inlet temperatures ever higher, gas turbines equipped with both lean premixed combustors and selective catalytic reduction after treatment eventually will be unable to meet the new emission goals of sub-3 ppm NOx. New gas turbine combustors are needed with lower emissions than the current state-of-the-art lean premixed combustors. In this program an advanced combustion system for the next generation of gas turbines is being developed with the goal of reducing combustor NOx emissions by 50% below the state-of-the-art. Dry Low NOx (DLN) technology is the current leader in NOx emission technology, guaranteeing 9 ppm NOx emissions for heavy duty F class gas turbines. This development program is directed at exploring advanced concepts which hold promise for meeting the low emissions targets. The trapped vortex combustor is an advanced concept in combustor design. It has been studied widely for aircraft engine applications because it has demonstrated the ability to maintain a stable flame over a wide range of fuel flow rates. Additionally, it has shown significantly lower NOx emission than a typical aircraft engine combustor and with low CO at the same time. The rapid CO burnout and low NOx production of this combustor made it a strong candidate for investigation. Incremental improvements to the DLN technology have not brought the dramatic improvements that are targeted in this program. A revolutionary combustor design is being explored because it captures many of the critical features needed to significantly reduce emissions. Experimental measurements of the combustor performance at atmospheric conditions were completed in the first phase of the program

  20. Radionuclide Gas Transport through Nuclear Explosion-Generated Fracture Networks

    PubMed Central

    Jordan, Amy B.; Stauffer, Philip H.; Knight, Earl E.; Rougier, Esteban; Anderson, Dale N.

    2015-01-01

    Underground nuclear weapon testing produces radionuclide gases which may seep to the surface. Barometric pumping of gas through explosion-fractured rock is investigated using a new sequentially-coupled hydrodynamic rock damage/gas transport model. Fracture networks are produced for two rock types (granite and tuff) and three depths of burial. The fracture networks are integrated into a flow and transport numerical model driven by surface pressure signals of differing amplitude and variability. There are major differences between predictions using a realistic fracture network and prior results that used a simplified geometry. Matrix porosity and maximum fracture aperture have the greatest impact on gas breakthrough time and window of opportunity for detection, with different effects between granite and tuff simulations highlighting the importance of accurately simulating the fracture network. In particular, maximum fracture aperture has an opposite effect on tuff and granite, due to different damage patterns and their effect on the barometric pumping process. From stochastic simulations using randomly generated hydrogeologic parameters, normalized detection curves are presented to show differences in optimal sampling time for granite and tuff simulations. Seasonal and location-based effects on breakthrough, which occur due to differences in barometric forcing, are stronger where the barometric signal is highly variable. PMID:26676058

  1. Radionuclide Gas Transport through Nuclear Explosion-Generated Fracture Networks.

    PubMed

    Jordan, Amy B; Stauffer, Philip H; Knight, Earl E; Rougier, Esteban; Anderson, Dale N

    2015-01-01

    Underground nuclear weapon testing produces radionuclide gases which may seep to the surface. Barometric pumping of gas through explosion-fractured rock is investigated using a new sequentially-coupled hydrodynamic rock damage/gas transport model. Fracture networks are produced for two rock types (granite and tuff) and three depths of burial. The fracture networks are integrated into a flow and transport numerical model driven by surface pressure signals of differing amplitude and variability. There are major differences between predictions using a realistic fracture network and prior results that used a simplified geometry. Matrix porosity and maximum fracture aperture have the greatest impact on gas breakthrough time and window of opportunity for detection, with different effects between granite and tuff simulations highlighting the importance of accurately simulating the fracture network. In particular, maximum fracture aperture has an opposite effect on tuff and granite, due to different damage patterns and their effect on the barometric pumping process. From stochastic simulations using randomly generated hydrogeologic parameters, normalized detection curves are presented to show differences in optimal sampling time for granite and tuff simulations. Seasonal and location-based effects on breakthrough, which occur due to differences in barometric forcing, are stronger where the barometric signal is highly variable. PMID:26676058

  2. Radionuclide gas transport through nuclear explosion-generated fracture networks

    SciTech Connect

    Jordan, Amy B.; Stauffer, Philip H.; Knight, Earl E.; Rougier, Esteban; Anderson, Dale N.

    2015-12-17

    Underground nuclear weapon testing produces radionuclide gases which may seep to the surface. Barometric pumping of gas through explosion-fractured rock is investigated using a new sequentially-coupled hydrodynamic rock damage/gas transport model. Fracture networks are produced for two rock types (granite and tuff) and three depths of burial. The fracture networks are integrated into a flow and transport numerical model driven by surface pressure signals of differing amplitude and variability. There are major differences between predictions using a realistic fracture network and prior results that used a simplified geometry. Matrix porosity and maximum fracture aperture have the greatest impact on gas breakthrough time and window of opportunity for detection, with different effects between granite and tuff simulations highlighting the importance of accurately simulating the fracture network. In particular, maximum fracture aperture has an opposite effect on tuff and granite, due to different damage patterns and their effect on the barometric pumping process. From stochastic simulations using randomly generated hydrogeologic parameters, normalized detection curves are presented to show differences in optimal sampling time for granite and tuff simulations. In conclusion, seasonal and location-based effects on breakthrough, which occur due to differences in barometric forcing, are stronger where the barometric signal is highly variable.

  3. Radionuclide Gas Transport through Nuclear Explosion-Generated Fracture Networks

    NASA Astrophysics Data System (ADS)

    Jordan, Amy B.; Stauffer, Philip H.; Knight, Earl E.; Rougier, Esteban; Anderson, Dale N.

    2015-12-01

    Underground nuclear weapon testing produces radionuclide gases which may seep to the surface. Barometric pumping of gas through explosion-fractured rock is investigated using a new sequentially-coupled hydrodynamic rock damage/gas transport model. Fracture networks are produced for two rock types (granite and tuff) and three depths of burial. The fracture networks are integrated into a flow and transport numerical model driven by surface pressure signals of differing amplitude and variability. There are major differences between predictions using a realistic fracture network and prior results that used a simplified geometry. Matrix porosity and maximum fracture aperture have the greatest impact on gas breakthrough time and window of opportunity for detection, with different effects between granite and tuff simulations highlighting the importance of accurately simulating the fracture network. In particular, maximum fracture aperture has an opposite effect on tuff and granite, due to different damage patterns and their effect on the barometric pumping process. From stochastic simulations using randomly generated hydrogeologic parameters, normalized detection curves are presented to show differences in optimal sampling time for granite and tuff simulations. Seasonal and location-based effects on breakthrough, which occur due to differences in barometric forcing, are stronger where the barometric signal is highly variable.

  4. Testing and Functions of the J2X Gas Generator

    NASA Technical Reports Server (NTRS)

    Miller, Nicholas

    2009-01-01

    The Ares I, NASA s new solid rocket based crew launch vehicle, is a two stage in line rocket that has made its waytothe forefront of NASA s endeavors. The Ares I s Upper Stage (US) will be propelled by a J-2X engine which is fueled by liquid hydrogen and liquid oxygen. The J-2X is a variation based on two of its predecessor s, the J-2 and J-2S engines. ET50 is providing the design support for hardware required to run tests on the J-2X Gas Generator (GG) that increases the delivery pressure of the supplied combustion fuels that the engine burns. The test area will be running a series of tests using different lengths and curved segments of pipe and different sized nozzles to determine the configuration that best satisfies the thrust, heat, and stability requirements for the engine. I have had to research the configurations that are being tested and gain an understanding of the purpose of the tests. I then had to research the parts that would be used in the test configurations. I was taken to see parts similar to the ones used in the test configurations and was allowed to review drawings and dimensions used for those parts. My job over this summer has been to use the knowledge I have gained to design, model, and create drawings for the un-fabricated parts that are necessary for the J-2X Workhorse Gas Generator Phase IIcTest.

  5. NASA Fastrac Engine Gas Generator Component Test Program and Results

    NASA Technical Reports Server (NTRS)

    Dennis, Henry J., Jr.; Sanders, T.

    2000-01-01

    Low cost access to space has been a long-time goal of the National Aeronautics and Space Administration (NASA). The Fastrac engine program was begun at NASA's Marshall Space Flight Center to develop a 60,000-pound (60K) thrust, liquid oxygen/hydrocarbon (LOX/RP), gas generator-cycle booster engine for a fraction of the cost of similar engines in existence. To achieve this goal, off-the-shelf components and readily available materials and processes would have to be used. This paper will present the Fastrac gas generator (GG) design and the component level hot-fire test program and results. The Fastrac GG is a simple, 4-piece design that uses well-defined materials and processes for fabrication. Thirty-seven component level hot-fire tests were conducted at MSFC's component test stand #116 (TS116) during 1997 and 1998. The GG was operated at all expected operating ranges of the Fastrac engine. Some minor design changes were required to successfully complete the test program as development issues arose during the testing. The test program data results and conclusions determined that the Fastrac GG design was well on the way to meeting the requirements of NASA's X-34 Pathfinder Program that chose the Fastrac engine as its main propulsion system.

  6. Reactive Transport Modeling of Acid Gas Generation and Condensation

    SciTech Connect

    G. Zhahg; N. Spycher; E. Sonnenthal; C. Steefel

    2005-01-25

    Pulvirenti et al. (2004) recently conducted a laboratory evaporation/condensation experiment on a synthetic solution of primarily calcium chloride. This solution represents one potential type of evaporated pore water at Yucca Mountain, Nevada, a site proposed for geologic storage of high-level nuclear waste. These authors reported that boiling this solution to near dryness (a concentration factor >75,000 relative to actual pore waters) leads to the generation of acid condensate (pH 4.5) presumably due to volatilization of HCl (and minor HF and/or HNO{sub 3}). To investigate the various processes taking place, including boiling, gas transport, and condensation, their experiment was simulated by modifying an existing multicomponent and multiphase reactive transport code (TOUGHREACT). This code was extended with a Pitzer ion-interaction model to deal with high ionic strength. The model of the experiment was set-up to capture the observed increase in boiling temperature (143 C at {approx}1 bar) resulting from high concentrations of dissolved salts (up to 8 m CaCl{sub 2}). The computed HCI fugacity ({approx} 10{sup -4} bars) generated by boiling under these conditions is not sufficient to lower the pH of the condensate (cooled to 80 and 25 C) down to observed values unless the H{sub 2}O mass fraction in gas is reduced below {approx}10%. This is because the condensate becomes progressively diluted by H{sub 2}O gas condensation. However, when the system is modeled to remove water vapor, the computed pH of instantaneous condensates decreases to {approx}1.7, consistent with the experiment (Figure 1). The results also show that the HCl fugacity increases, and calcite, gypsum, sylvite, halite, MgCl{sub 2}4H{sub 2}O and CaCl{sub 2} precipitate sequentially with increasing concentration factors.

  7. Counter-Rotatable Fan Gas Turbine Engine with Axial Flow Positive Displacement Worm Gas Generator

    NASA Technical Reports Server (NTRS)

    Giffin, Rollin George (Inventor); Murrow, Kurt David (Inventor); Fakunle, Oladapo (Inventor)

    2014-01-01

    A counter-rotatable fan turbine engine includes a counter-rotatable fan section, a worm gas generator, and a low pressure turbine to power the counter-rotatable fan section. The low pressure turbine maybe counter-rotatable or have a single direction of rotation in which case it powers the counter-rotatable fan section through a gearbox. The gas generator has inner and outer bodies having offset inner and outer axes extending through first, second, and third sections of a core assembly. At least one of the bodies is rotatable about its axis. The inner and outer bodies have intermeshed inner and outer helical blades wound about the inner and outer axes and extending radially outwardly and inwardly respectively. The helical blades have first, second, and third twist slopes in the first, second, and third sections respectively. A combustor section extends through at least a portion of the second section.

  8. Estimating methane gas generation from Devil's swamp landfill using greenhouse gas emission models

    NASA Astrophysics Data System (ADS)

    Adeyemi, Ayodeji Thompson

    Greenhouse gas (GHG) has been a key issue in the study, design, and management of landfills. Landfill gas (LFG) is considered either as a significant source of renewable energy (if extracted and processed accordingly) or significant source of pollution and risk (if not mitigated or processed). A municipal solid waste (MSW) landfill emits a significant amount of methane, a potent GHG. Thus, quantification and mitigation of GHG emissions is an important area of study in engineering and other sciences related to landfill technology and management. The present study will focus on estimating methane generation from Devils swamp landfill (DSLF), a closed landfill in Baton Rouge, LA. The landfill operated for 53 years (1940-1993) and contains both industrial and municipal waste products. Since the Clean Air Act of 1963, landfills are now classified as New Source Performance Standard (NSPS) waste (i.e., waste that will decompose to generate LFG). Currently, the DSLF is being used as source of renewable energy through the "Waste to Energy" program. For this study, to estimate the methane potential in the DSLF, it is important to determine the characteristics and classification of the landfill's wastes. The study uses and compares different GHG modeling tools---LandGEM, a multiphase model, and a simple first-order model---to estimate methane gas emission and compare results with the actual emissions from the DSLF. The sensitivity of the methane generation rate was analyzed by the methane generation models to assess the effects of variables such as initial conditions, specific growth rate, and reaction rate constants. The study concludes that methane (L0) and initial organic concentration in waste (k) are the most important parameters when estimating methane generation using the models.

  9. Densified biomass can cost-effectively mitigate greenhouse gas emissions and address energy security in thermal applications.

    PubMed

    Wilson, Thomas O; McNeal, Frederick M; Spatari, Sabrina; G Abler, David; Adler, Paul R

    2012-01-17

    Regional supplies of biomass are currently being evaluated as feedstocks in energy applications to meet renewable portfolio (RPS) and low carbon fuel standards. We investigate the life cycle greenhouse gas (GHG) emissions and associated abatement costs resulting from using densified switchgrass for thermal and electrical energy. In contrast to the large and positive abatement costs for using biomass in electricity generation ($149/Mg CO(2)e) due to the low cost of coal and high feedstock and power plant operation costs, abatement costs for replacing fuel oil with biomass in thermal applications are large and negative (-$52 to -$92/Mg CO(2)e), resulting in cost savings. Replacing fuel oil with biomass in thermal applications results in least cost reductions compared to replacing coal in electricity generation, an alternative that has gained attention due to RPS legislation and the centralized production model most often considered in U.S. policy. Our estimates indicate a more than doubling of liquid fuel displacement when switchgrass is substituted for fuel oil as opposed to gasoline, suggesting that, in certain U.S. locations, such as the northeast, densified biomass would help to significantly decarbonize energy supply with regionally sourced feedstock, while also reducing imported oil. On the basis of supply projections from the recently released Billion Ton Report, there will be enough sustainably harvested biomass available in the northeast by 2022 to offset the entirety of heating oil demand in the same region. This will save NE consumers between $2.3 and $3.9 billion annually. Diverting the same resource to electricity generation would cost the region $7.7 billion per year. While there is great need for finding low carbon substitutes for coal power and liquid transportation fuels in the U.S., we argue that in certain regions it makes cost- (and GHG mitigation-) effective sense to phase out liquid heating fuels with locally produced biomass first. PMID

  10. Mi-STAR: Designing Integrated Science Curriculum to Address the Next Generation Science Standards and Their Foundations

    NASA Astrophysics Data System (ADS)

    Gochis, E. E.; Huntoon, J. E.

    2015-12-01

    Mi-STAR (Michigan Science Teaching and Assessment Reform, http://mi-star.mtu.edu/) was funded by the Herbert H. and Grace A. Dow Foundation to reform K-12 science education to present science as an integrated body of knowledge that is applied to address societal issues. To achieve this goal, Mi-STAR is developing an integrated science curriculum for the middle grades that will be aligned with the Next Generation Science Standards (NGSS). Similar to the geosciences, the curriculum requires the integration of science, engineering and math content to explore 21st-century issues and demonstrates how these concepts can be used in service of society. The curriculum is based on the Mi-STAR Unit Specification Chart which pairs interdisciplinary themes with bundled NGSS Performance Expectations. Each unit is developed by a collaborative team of K-12 teachers, university STEM content experts and science education experts. Prior to developing a unit, each member on the team attends the on-line Mi-STAR Academy, completing 18+ hours of professional development (PD). This on-line PD program familiarizes teachers and experts with necessary pedagogical and content background knowledge, including NGSS and three-dimensional learning. With this background, teams use a staged, backwards design process to craft a multi-week unit based on a series of performance based tasks, or 'challenges' that engage students in actively doing science and engineering. Each unit includes Disciplinary Core Ideas from multiple disciplines, which focus on local and familiar examples that demonstrate the relevance of science in student's lives. Performance-based assessments are interwoven throughout the unit. Mi-STAR units will go through extensive pilot testing in several school districts across the state of Michigan. Additionally, the Mi-STAR program will develop teacher professional development programs to support implementation of the curriculum and design a pre-service teacher program in integrated

  11. Removal of Dioxin Contamination for Gas Turbine Generator Set Repair

    SciTech Connect

    Fay, W. S.; Borah, R.E.

    2003-02-25

    Decontamination projects are typically undertaken in the interest of reducing disposal costs. This goal can be achieved because decontamination concentrates the contaminant into a smaller volume or changes its form so that a lower cost disposal technology becomes available. Less frequently, decontamination adds value back to the fouled structure or contaminated piece of equipment. This removal of dioxins from a gas turbine generator set is one of the latter cases. A multi-million dollar piece of equipment could have been destined for the scrap pile. Instead, an innovative, non-destructive decontamination technology, developed under EPA and DOE demonstration programs has was employed so that the set could repaired and put back into service. The TechXtractchemical decontamination technology reduced surface dioxin / furan concentrations from as high as 24,000 ng / m2 to less than 25 ng / m2 and below detection limits.

  12. High-pressure LOX/hydrocarbon preburners and gas generators

    NASA Technical Reports Server (NTRS)

    Huebner, A. W.

    1981-01-01

    The objective of the program was to conduct a small scale hardware test program to establish the technology base required for LOX/hydrocarbon preburners and gas generators. The program consisted of six major tasks; Task I reviewed and assessed the performance prediction models and defined a subscale test program. Task II designed and fabricated this subscale hardware. Task III tested and analyzed the data from this hardware. Task IV analyzed the hot fire results and formulated a preliminary design for 40K preburner assemblies. Task V took the preliminary design and detailed and fabricated three 40K size preburner assemblies, one each fuel-rich LOX/CH, and LOX/RP-1 and one oxidizer rich LOX/CH4. Task VI delivered these preburner assemblies to MSFC for subsequent evaluation.

  13. Radionuclide gas transport through nuclear explosion-generated fracture networks

    DOE PAGESBeta

    Jordan, Amy B.; Stauffer, Philip H.; Knight, Earl E.; Rougier, Esteban; Anderson, Dale N.

    2015-12-17

    Underground nuclear weapon testing produces radionuclide gases which may seep to the surface. Barometric pumping of gas through explosion-fractured rock is investigated using a new sequentially-coupled hydrodynamic rock damage/gas transport model. Fracture networks are produced for two rock types (granite and tuff) and three depths of burial. The fracture networks are integrated into a flow and transport numerical model driven by surface pressure signals of differing amplitude and variability. There are major differences between predictions using a realistic fracture network and prior results that used a simplified geometry. Matrix porosity and maximum fracture aperture have the greatest impact on gasmore » breakthrough time and window of opportunity for detection, with different effects between granite and tuff simulations highlighting the importance of accurately simulating the fracture network. In particular, maximum fracture aperture has an opposite effect on tuff and granite, due to different damage patterns and their effect on the barometric pumping process. From stochastic simulations using randomly generated hydrogeologic parameters, normalized detection curves are presented to show differences in optimal sampling time for granite and tuff simulations. In conclusion, seasonal and location-based effects on breakthrough, which occur due to differences in barometric forcing, are stronger where the barometric signal is highly variable.« less

  14. BIOMASS GASIFICATION AND POWER GENERATION USING ADVANCED GAS TURBINE SYSTEMS

    SciTech Connect

    David Liscinsky

    2002-10-20

    A multidisciplined team led by the United Technologies Research Center (UTRC) and consisting of Pratt & Whitney Power Systems (PWPS), the University of North Dakota Energy & Environmental Research Center (EERC), KraftWork Systems, Inc. (kWS), and the Connecticut Resource Recovery Authority (CRRA) has evaluated a variety of gasified biomass fuels, integrated into advanced gas turbine-based power systems. The team has concluded that a biomass integrated gasification combined-cycle (BIGCC) plant with an overall integrated system efficiency of 45% (HHV) at emission levels of less than half of New Source Performance Standards (NSPS) is technically and economically feasible. The higher process efficiency in itself reduces consumption of premium fuels currently used for power generation including those from foreign sources. In addition, the advanced gasification process can be used to generate fuels and chemicals, such as low-cost hydrogen and syngas for chemical synthesis, as well as baseload power. The conceptual design of the plant consists of an air-blown circulating fluidized-bed Advanced Transport Gasifier and a PWPS FT8 TwinPac{trademark} aeroderivative gas turbine operated in combined cycle to produce {approx}80 MWe. This system uses advanced technology commercial products in combination with components in advanced development or demonstration stages, thereby maximizing the opportunity for early implementation. The biofueled power system was found to have a levelized cost of electricity competitive with other new power system alternatives including larger scale natural gas combined cycles. The key elements are: (1) An Advanced Transport Gasifier (ATG) circulating fluid-bed gasifier having wide fuel flexibility and high gasification efficiency; (2) An FT8 TwinPac{trademark}-based combined cycle of approximately 80 MWe; (3) Sustainable biomass primary fuel source at low cost and potentially widespread availability-refuse-derived fuel (RDF); (4) An overall integrated

  15. Radiolytic gas generation in salt cake technical task plan

    SciTech Connect

    Walker, D.D.; Crawford, C.L.; Bibler, N.E.

    1993-08-29

    High-level radioactive wastes are stored in large, steel tanks in the Savannah River Site Tank Farms. The liquid levels in these tanks are monitored to detect leakage of waste out of tanks or leakage of liquids into the tanks. Recent unexplained level fluctuations in high-level waste (HLW) tanks have caused High Level Waste Engineering (HLWE) to develop a program to better understand tank level behavior. Interim Waste Technology (IWT) has been requested by HLWE to obtain data which will lead to a better understanding of the radiolytic generations of gases in salt cake. The task described below will provide data from laboratory experiments with simulated wastes which can be used in tank level fluctuation modeling. The following experimental programs have been formulated to meet the task requirements of the customer: (A) determine whether radiolytically generated gas bubbles can be trapped in salt cake; (B) determine the composition of gases produced by radiolysis; (C) determine the yield of radiolysis gases as a function of radiation dose; (D) determine bubble distribution.

  16. Gas generation phenomena in radioactive waste transportation packaging

    SciTech Connect

    Nigrey, P.J.

    1997-11-01

    The interaction of radiation from radioactive materials with the waste matrix can lead to the deterioration of the waste form resulting in the possible formation of gaseous species. Depending on the type and characteristics of the radiation source, the generation of hydrogen may predominate. Since the interaction of alpha particles with the waste form results in significant energy transfer, other gases such as carbon oxides, methane, nitrogen oxides, oxygen, water, and helium are possible. The type of gases produced from the waste forms is determined by the mechanisms involved in the waste degradation. For transuranic wastes, the identified degradation mechanisms are reported to be caused by radiolysis, thermal decomposition or dewatering, chemical corrosion, and bacterial action. While all these mechanisms may be responsible for the buildup of gases during the storage of wastes, radiolysis and thermal decomposition appear to be the main contributors during waste transport operations. In this paper, the authors provide a review of applicable gas generation data resulting from the degradation of various waste forms under conditions typical for transport. The effects of radiolytic and thermal degradation mechanisms will be discussed in the context of transportation safety.

  17. Roadmapping the Resolution of Gas Generation Issues in Packages Containing Radioactive Waste/Materials - A Status Report

    SciTech Connect

    Luke, D.E.; Hamp, S.

    2002-01-04

    Gas generation issues, particularly hydrogen, have been an area of concern for the transport and storage of radioactive materials and waste in the Department of Energy (DOE) Complex. Potentially combustible gases can be generated through a variety of reactions, including chemical reactions and radiolytic decomposition of hydrogen-containing material. Since transportation regulations prohibit shipment of explosives and radioactive materials together, it was decided that hydrogen generation was a problem that warranted the execution of a high-level roadmapping effort. This paper discusses the major gas generation issues within the DOE Complex and the research that has been and is being conducted by the transuranic (TRU) waste, nuclear materials, and spent nuclear fuels (SNF) programs within DOE's Environmental Management (EM) organizations to address gas generation concerns. This paper presents a ''program level'' roadmap that links technology development to program needs and identifies the probability of success in an effort to understand the programmatic risk associated with the issue of gas generation. This paper also presents the status of the roadmap and follow-up activities.

  18. Roadmapping the Resolution of Gas Generation Issues in Packages Containing Radioactive Waste/Materials - A Status Report

    SciTech Connect

    Luke, Dale Elden; Hamp, S.

    2002-02-01

    Gas generation issues, particularly hydrogen, have been an area of concern for the transport and storage of radioactive materials and waste in the Department of Energy (DOE) Complex. Potentially combustible gases can be generated through a variety of reactions, including chemical reactions and radiolytic decomposition of hydrogen- containing material. Since transportation regulations prohibit shipment of explosives and radioactive materials together, it was decided that hydrogen generation was a problem that warranted the execution of a high-level roadmapping effort. This paper discusses the major gas generation issues within the DOE Complex and the research that has been and is being conducted by the transuranic (TRU) waste, nuclear materials, and spent nuclear fuels (SNF) programs within DOE’s Environmental Management (EM) organizations to address gas generation concerns. This paper presents a "program level" roadmap that links technology development to program needs and identifies the probability of success in an effort to understand the programmatic risk associated with the issue of gas generation. This paper also presents the status of the roadmap and follow-up activities.

  19. Gas-geochemical condition and ecological functions of urban soils in areas with gas generating grounds

    NASA Astrophysics Data System (ADS)

    Mozharova, Nadezhda; Lebed-Sharlevich, Iana; Kulachkova, Svetlana

    2014-05-01

    Rapid urbanization and expansion of city borders lead to development of new areas, often following with relief changes, covering of gully-ravine systems and river beds with technogenic grounds containing construction and municipal waste. Decomposition of organic matter in these grounds is a source of methane and carbon dioxide. Intensive generation and accumulation of CO2 and CH4 into grounds may cause a fire and explosion risk for constructed objects. Gases emission to the atmosphere changes the global balance of GHGs and negatively influences on human health. The aim of this investigation is to study gas-geochemical condition and ecological functions of urban soils in areas with gas generating grounds. Studied areas are the gully-ravine systems or river beds, covered with technogenic grounds during land development. Stratigraphic columns of these grounds are 5-17 meters of man-made loamy material with inclusion of construction waste. Gas generating layer with increased content of organic matter, reductive conditions and high methanogenic activity (up to 1.0 ng*g-1*h-1) is situated at the certain depth. Maximum CH4 and CO2 concentrations in this layer reach dangerous values (2-10% and 11%, respectively) in the current standards. In case of disturbance of ground layer (e.g. well-drilling) methane is rapidly transferred by convective flux to atmosphere. The rate of CH4 emission reaches 100 mg*m-2*h-1 resulting in its atmospheric concentration growth by an order of magnitude compared with background. In normal occurrence of grounds methane gradually diffuses into the upper layers by pore space, consuming on different processes (e.g. formation of organic matter, nitrogen compounds or specific particles of magnetite), and emits to atmosphere. CH4 emission rate varies from 1 to 40 mg*m-2*h-1 increasing with depth of grounds. Carbon dioxide emission is about 100 mg*m-2*h-1. During soil formation on gas generating grounds bacterial oxidation of methane, one of the most

  20. Next Generation * Natural Gas (NG)2 Information Requirements--Executive Summary

    EIA Publications

    2000-01-01

    The Energy Information Administration (EIA) has initiated the Next Generation * Natural Gas (NG)2 project to design and implement a new and comprehensive information program for natural gas to meet customer requirements in the post-2000 time frame.

  1. Greenhouse Gas Abatement with Distributed Generation in California's Commercial Buildings

    SciTech Connect

    Stadler, Michael; Marnay, Chris; Cardoso, Goncalo; Megel, Olivier; Siddiqui, Afzal; Lai, Judy

    2009-08-15

    Lawrence Berkeley National Laboratory (LBL) is working with the California Energy Commission (CEC) to determine the role of distributed generation (DG) in greenhouse gas reductions. The impact of DG on large industrial sites is well known, and mostly, the potentials are already harvested. In contrast, little is known about the impact of DG on commercial buildings with peak electric loads ranging from 100 kW to 5 MW. We examine how DG with combined heat and power (CHP) may be implemented within the context of a cost minimizing microgrid that is able to adopt and operate various smart energy technologies, such as thermal and photovoltaic (PV) on-site generation, heat exchangers, solar thermal collectors, absorption chillers, and storage systems. We use a mixed-integer linear program (MILP) that has the minimization of a site's annual energy costs as objective. Using 138 representative commercial sites in California (CA) with existing tariff rates and technology data, we find the greenhouse gas reduction potential for California's commercial sector. This paper shows results from the ongoing research project and finished work from a two year U.S. Department of Energy research project. To show the impact of the different technologies on CO2 emissions, several sensitivity runs for different climate zones within CA with different technology performance expectations for 2020 were performed. The considered sites can contribute between 1 Mt/a and 1.8 Mt/a to the California Air Resources Board (CARB) goal of 6.7Mt/a CO2 abatement potential in 2020. Also, with lower PV and storage costs as well as consideration of a CO2 pricing scheme, our results indicate that PV and electric storage adoption can compete rather than supplement each other when the tariff structure and costs of electricity supply have been taken into consideration. To satisfy the site's objective of minimizing energy costs, the batteries will be charged also by CHP systems during off-peak and mid-peak hours and

  2. Development and application of an analysis methodology for interpreting ambiguous historical pressure data in the WIPP gas-generation experiments.

    SciTech Connect

    Felicione, F. S.

    2006-01-23

    The potential for generation of gases in transuranic (TRU) waste by microbial activity, chemical interactions, corrosion, and radiolysis was addressed in the Argonne National Laboratory-West (ANL-West) Gas-Generation Experiments (GGE). Data was collected over several years by simulating the conditions in the Waste Isolation Pilot Plant (WIPP) after the eventual intrusion of brine into the repository. Fourteen test containers with various actual TRU waste immersed in representative brine were inoculated with WIPP-relevant microbes, pressurized with inert gases, and kept in an inert-atmosphere environment for several years to provide estimates of the gas-generation rates that will be used in computer models for future WIPP Performance Assessments. Modest temperature variations occurred during the long-term ANL-West experiments. Although the experiment temperatures always remained well within the experiment specifications, the small temperature variation was observed to affect the test container pressure far more than had been anticipated. In fact, the pressure variations were so large, and seemingly erratic, that it was impossible to discern whether the data was even valid and whether the long-term pressure trend was increasing, decreasing, or constant. The result was that no useful estimates of gas-generation rates could be deduced from the pressure data. Several initial attempts were made to quantify the pressure fluctuations by relating these to the measured temperature variation, but none was successful. The work reported here carefully analyzed the pressure measurements to determine if these were valid or erroneous data. It was found that a thorough consideration of the physical phenomena that were occurring can, in conjunction with suitable gas laws, account quite accurately for the pressure changes that were observed. Failure of the earlier attempts to validate the data was traced to the omission of several phenomena, the most important being the variation in

  3. A New Tritium Gas Generator for the Activity Standardization of Tritiated Water by Internal Gas Proportional Counting

    SciTech Connect

    Stanga, D.; Moreau, L.; Picolo, J.L.; Cassette, P

    2005-07-15

    Tritiated water can be standardized by internal gas proportional counting following its chemical reduction, by means of a tritium gas generator, to produce tritiated hydrogen. In this paper a new tritium gas generator is described in detail together with the method of measurement based on the internal gas counting. It has new and improved features and offers the advantage of being simpler and easier to operate than other tritium generators available. Thus, this tritium generator has the following new features: (i) it performs the water reduction at a lower temperature (450 deg. C) than the other generators which need 600 deg. C ; (ii) the reduction yield is always unitary. Also, it has a simple and compact construction by using the same components for water degassing and water reduction. Its simple disassembly and reassembly allow for easy maintenance.

  4. Electrolytic phenomena and massive gas generation around pacemaker electrodes. Clinical presentation of an unusual pacing failure.

    PubMed

    Di Luzio, V; Curzi, G; Capestro, F; Boccanelli, A; Renzi, R

    1975-12-01

    An unexpected clinical presentation of an unusual pacing failure has been observed in two patients who had had recent implantation of a pacemaker model whose electrodes were made of an nonnoble metal alloy. An intermittent current leakage from the output capacitor and possibly from the output transistor accounted for electrolytic corrosion at the anode, premature depletion of the battery, heart muscle damage and for massive gas generation around electrodes, leading to right ventricular perforation, pneumopericardium and subcutaneous thoracic emphysema. The occurrence of this syndrome shows that, if nonnoble metals are used for electrodes, more attention should be addressed to those conditions which add to polarization problems, as is current leakage from the output circuit components. PMID:1193114

  5. TRU waste transportation -- The flammable gas generation problem

    SciTech Connect

    Connolly, M.J.; Kosiewicz, S.T.

    1997-11-01

    The Nuclear Regulatory Commission (NRC) has imposed a flammable gas (i.e., hydrogen) concentration limit of 5% by volume on transuranic (TRU) waste containers to be shipped using the TRUPACT-II transporter. This concentration is the lower explosive limit (LEL) in air. This was done to minimize the potential for loss of containment during a hypothetical 60 day period. The amount of transuranic radionuclide that is permissible for shipment in TRU waste containers has been tabulated in the TRUPACT-II Safety Analysis Report for Packaging (SARP, 1) to conservatively prevent accumulation of hydrogen above this 5% limit. Based on the SARP limitations, approximately 35% of the TRU waste stored at the Idaho National Engineering and Environmental Lab (INEEL), Los Alamos National Lab (LANL), and Rocky Flats Environmental Technology Site (RFETS) cannot be shipped in the TRUPACT-II. An even larger percentage of the TRU waste drums at the Savannah River Site (SRS) cannot be shipped because of the much higher wattage loadings of TRU waste drums in that site`s inventory. This paper presents an overview of an integrated, experimental program that has been initiated to increase the shippable portion of the Department of Energy (DOE) TRU waste inventory. In addition, the authors will estimate the anticipated expansion of the shippable portion of the inventory and associated cost savings. Such projection should provide the TRU waste generating sites a basis for developing their TRU waste workoff strategies within their Ten Year Plan budget horizons.

  6. Gas Generation Testing of Neptunium Oxide Generated Using the HB-Line Phase IIFlowsheet

    SciTech Connect

    Duffey, J

    2003-08-29

    The hydrogen (H{sub 2}) gas generation rate for neptunium dioxide (NpO{sub 2}) samples produced on a laboratory scale using the HB-Line Phase II flowsheet has been measured following exposure to 75% relative humidity (RH). As expected, the observed H{sub 2} generation rates for these samples increase with increasing moisture content. A maximum H{sub 2} generation rate of 1.8 x 10{sup -6} moles per day per kilogram (mol {center_dot} day{sup -1} kg{sup -1}) was observed for NpO{sub 2} samples with approximately one and one-half times (1 1/2 X) the expected specific surface area (SSA) for the HB-Line Phase II product. The SSA of NpO{sub 2} samples calcined at 650 C is similar to plutonium dioxide (PuO{sub 2}) calcined at 950 C according to the Department of Energy (DOE) standard for packaging and storage of PuO{sub 2}. This low SSA of the HB-Line Phase II product limits moisture uptake to less than 0.2 weight percent (wt %) even with extended exposure to 75% RH.

  7. Results of Laboratory and Industrial Tests of Periodic-Type Gas Generators

    NASA Astrophysics Data System (ADS)

    Karp, I. N.; P‧yanykh, K. E.; Antoshchuk, T. A.; Lysenko, A. A.

    2015-05-01

    Results of laboratory and industrial tests of periodic-type gas generators burning various solid biofuels have been presented. The tests were carried out with the aim of obtaining producer gas which could totally or partly replace natural gas in power equipment burning gaseous fuel. The energy and environmental characteristics of a boiler unit burning a mixture of producer gas and natural gas have been assessed.

  8. The South Carolina Amazing Coast Program: Using Ocean Sciences to Address Next Generation Science Standards in Grades 3-5

    NASA Astrophysics Data System (ADS)

    Bell, E. V.; Thomas, C.; Weiss, B.; Bliss, A.; Spence, L.

    2013-12-01

    The Next Generation Science Standards (NGSS) are more inclusive of ocean sciences than the National Science Standards and respective state science standards. In response, the Center for Ocean Sciences Education Excellence-SouthEast (COSEE SE) is piloting the South Carolina's Amazing Coast (SCAC) program: a three-year initiative that incorporates ocean science concepts in grades 3-5 with the goals of addressing NGSS, STEM (science-technology-engineering-math) disciplines, and inquiry skills. The SCAC program targeted two Charleston County, South Carolina elementary schools that were demographically similar: Title 1 status (75% free or reduced lunch), > 90% African American student population, grade level size <55, and proximity to tidal salt marsh or barrier islands (< 2 miles). Fourteen teachers and approximately 240 students participated in the SCAC program between 2010 and 2013. The SCAC framework uses a scaffolding and multi-pronged approach for teacher professional development and student engagement. The scaffolding approach to curriculum implementation focuses on one grade level per year (Year 1 = 3rd; Year 2 = 4th, and Year 3 = 5th), thus building student and teacher literacy in ocean sciences. The coach-mentor model of teacher professional development was also used for the implementation of the program which differs from the traditional 'train the trainer' method in allowing for more frequent and consistent interaction by COSEE SE staff with the students and teachers during the school year. The coach mentor model enabled the creation of a community of practice where teachers served as both learners and practitioners of student learning. Methods for student engagement aligned with the NGSS and included hands-on classroom activities, use of 'hook' species such as loggerhead sea turtles (Caretta caretta), diamondback terrapins (Malaclemys terrapin) and smooth cord grass (Spartina alterniflora), field experiences to explore local ecosystems, interactions with

  9. Investigation of gas generation in regenerative fuel cells by low-energy X-rays

    NASA Astrophysics Data System (ADS)

    Selamet, Omer Faruk; Deevanhxay, Phengxay; Tsushima, Shohji; Hirai, Shuichiro

    2015-11-01

    Gas generation and discharge behaviors in an operating regenerative fuel cell (RFC) are investigated using low-energy X-ray radiography. In situ visualization at high spatial and temporal resolution reveal dynamic and inhomogeneous behaviors of the gas generation in the membrane electrode assembly (MEA) in the RFC. Temporal and spatial variation of the gas thickness in the MEA is quantitatively discussed and shows an intermittent and periodic discharge processes of the gas generated by electrolysis, suggesting that the reaction sites in the catalyst layer and the discharging path of gas bubbles are well established in the MEA for the electrolysis. Larger gas accumulation and discharge in the gas diffusion layer (GDL) under the ribs are identified in comparison with those under the channels, which is attributed to the relatively longer path for accumulated gas under the ribs to be discharged into the flow channels.

  10. DESIGN, FABRICATION, AND TESTING OF AN ADVANCED, NON-POLLUTING TURBINE DRIVE GAS GENERATOR

    SciTech Connect

    Unknown

    2002-03-31

    The objectives of this report period were to complete the development of the Gas Generator design, which was done; fabricate and test of the non-polluting unique power turbine drive gas Gas Generator, which has been postponed. Focus during this report period has been to complete the brazing and bonding necessary to fabricate the Gas Generator hardware, continue making preparations for fabricating and testing the Gas Generator, and continuing the fabrication of the Gas Generator hardware and ancillary hardware in preparation for the test program. Fabrication is more than 95% complete and is expected to conclude in early May 2002. the test schedule was affected by relocation of the testing to another test supplier. The target test date for hot fire testing is now not earlier than June 15, 2002.

  11. Cover and startup gas supply system for solid oxide fuel cell generator

    DOEpatents

    Singh, P.; George, R.A.

    1999-07-27

    A cover and startup gas supply system for a solid oxide fuel cell power generator is disclosed. Hydrocarbon fuel, such as natural gas or diesel fuel, and oxygen-containing gas are supplied to a burner. Combustion gas exiting the burner is cooled prior to delivery to the solid oxide fuel cell. The system mixes the combusted hydrocarbon fuel constituents with hydrogen which is preferably stored in solid form to obtain a non-explosive gas mixture. The system may be used to provide both non-explosive cover gas and hydrogen-rich startup gas to the fuel cell. 4 figs.

  12. Cover and startup gas supply system for solid oxide fuel cell generator

    DOEpatents

    Singh, Prabhakar; George, Raymond A.

    1999-01-01

    A cover and startup gas supply system for a solid oxide fuel cell power generator is disclosed. Hydrocarbon fuel, such as natural gas or diesel fuel, and oxygen-containing gas are supplied to a burner. Combustion gas exiting the burner is cooled prior to delivery to the solid oxide fuel cell. The system mixes the combusted hydrocarbon fuel constituents with hydrogen which is preferably stored in solid form to obtain a non-explosive gas mixture. The system may be used to provide both non-explosive cover gas and hydrogen-rich startup gas to the fuel cell.

  13. Finding Purpose in Pain: Using Logotherapy as a Method for Addressing Survivor Guilt in First-Generation College Students

    ERIC Educational Resources Information Center

    Tate, Kevin A.; Williams, Cyrus, III; Harden, Dia

    2013-01-01

    First-generation college students face a variety of academic and personal challenges, including survivor guilt (Piorkowski, 1983). Survivor guilt for these students involves negative emotions related to leaving family and friends "behind" in difficult contexts and lived experiences. This article provides (a) an overview of first-generation college…

  14. Position paper on gas generation in the Waste Isolation Pilot Plant

    SciTech Connect

    Brush, L.H.

    1994-11-15

    Gas generation by transuranic (TRU) waste is a significant issue because gas will, if produced in significant quantities, affect the performance of the Waste Isolation Pilot Plant (WIPP) with respect to Environmental Protection Agency (EPA) regulations for the long-term isolation of radioactive and chemically hazardous waste. If significant gas production occurs, it will also affect, and will be affected by, other processes and parameters in WIPP disposal rooms. The processes that will produce gas in WIPP disposal rooms are corrosion, microbial activity and radiolysis. This position paper describes these processes and the models, assumptions and data used to predict gas generation in WIPP disposal rooms.

  15. FIRST ORDER KINETIC GAS GENERATION MODEL PARAMETERS FOR WET LANDFILLS

    EPA Science Inventory

    Landfill gas is produced as a result of a sequence of physical, chemical, and biological processes occurring within an anaerobic landfill. Landfill operators, energy recovery project owners, regulators, and energy users need to be able to project the volume of gas produced and re...

  16. Optimization of Gas Generation Testing of Contact-Handled Transuranic Solidified

    SciTech Connect

    Tamara Shokes; Kevin J. Liekhus; Vivian Bowman; Eric Schweinsberg

    2006-05-18

    The Contact-Handled Transuranic Waste Authorized methods for Payload Control (CH-TRAMPAC) requires that drums containing Waste Type IV (solidified organic waste) must be evaluated by gas generation testing (GGT) because a G-value, a measure of gas generation potential, has not been determined for Waste Type IV.

  17. Performance of a Small Gas Generator Using Liquid Hydrogen and Liquid Oxygen

    NASA Technical Reports Server (NTRS)

    Acker, Loren W.; Fenn, David B.; Dietrich, Marshall W.

    1961-01-01

    The performance and operating problems of a small hot-gas generator burning liquid hydrogen with liquid oxygen are presented. Two methods of ignition are discussed. Injector and combustion chamber design details based on rocket design criteria are also given. A carefully fabricated showerhead injector of simple design provided a gas generator that yielded combustion efficiencies of 93 and 96 percent.

  18. Analysis of Turkish High School Chemistry Textbooks and Teacher-Generated Questions about Gas Laws

    ERIC Educational Resources Information Center

    Nakiboglu, Canan; Yildirir, H.

    2011-01-01

    This study presents the results of an analysis of high school chemistry textbooks and teacher-generated questions about gas laws. The materials that were analyzed consisted of 456 questions about gas laws found in seven grade 10 chemistry textbooks and 264 teacher-generated examination questions prepared by seven chemistry teachers from three…

  19. Integrated flue gas cleaning for the next regulatory generation

    SciTech Connect

    Vincent, H.; Jones, G.

    1995-12-31

    Before the end of this decade, utilities and other major power producers burning solid/liquid fuels can expect the promulgation of further regulations mandated by the 1990 Clean Air Act Amendments. In particular, Title III, ``Air Toxics`` provision could profoundly change the manner how power producers will need to evaluate compliance technology options. Integrated gas cleaning concepts will be necessary to achieve compliance, maximize existing gas cleaning assets, and for the avoidance of pollution transfer. The paper describes several integrated gas cleaning concepts for multi-pollutant control for high sulfur coal, low sulfur coal, and oil burning power plants.

  20. Identifying Liquid-Gas System Misconceptions and Addressing Them Using a Laboratory Exercise on Pressure-Temperature Diagrams of a Mixed Gas Involving Liquid-Vapor Equilibrium

    ERIC Educational Resources Information Center

    Yoshikawa, Masahiro; Koga, Nobuyoshi

    2016-01-01

    This study focuses on students' understandings of a liquid-gas system with liquid-vapor equilibrium in a closed system using a pressure-temperature ("P-T") diagram. By administrating three assessment questions concerning the "P-T" diagrams of liquid-gas systems to students at the beginning of undergraduate general chemistry…

  1. Fuel Flexibility: Landfill Gas Contaminant Mitigation for Power Generation

    SciTech Connect

    Storey, John Morse; Theiss, Timothy J; Kass, Michael D; FINNEY, Charles E A; Lewis, Samuel; Kaul, Brian C; Besmann, Theodore M; Thomas, John F; Rogers, Hiram; Sepaniak, Michael

    2014-04-01

    This research project focused on the mitigation of silica damage to engine-based renewable landfill gas energy systems. Characterization of the landfill gas siloxane contamination, combined with characterization of the silica deposits in engines, led to development of two new mitigation strategies. The first involved a novel method for removing the siloxanes and other heavy contaminants from the landfill gas prior to use by the engines. The second strategy sought to interrupt the formation of hard silica deposits in the engine itself, based on inspection of failed landfill gas engine parts. In addition to mitigation, the project had a third task to develop a robust sensor for siloxanes that could be used to control existing and/or future removal processes.

  2. DESIGN, FABRICATION, AND TESTING OF AN ADVANCED, NON-POLLUTING TURBINE DRIVE GAS GENERATOR

    SciTech Connect

    Unknown

    2002-01-31

    The objective of this report period was to continue the development of the Gas Generator design, fabrication and test of the non-polluting unique power turbine drive Gas Generator. Focus during this past report period has been to continue completion the Gas Generator design, completing the brazing and bonding experiments to determine the best method and materials necessary to fabricate the Gas Generator hardware, continuing to making preparations for fabricating and testing this Gas Generator and commencing with the fabrication of the Gas Generator hardware and ancillary hardware. Designs have been completed sufficiently such that Long Lead Items [LLI] have been ordered and upon arrival will be readied for the fabrication process. The keys to this design are the platelet construction of the injectors that precisely measures/meters the flow of the propellants and water all throughout the steam generating process and the CES patented gas generating cycle. The Igniter Assembly injector platelets fabrication process has been completed and bonded to the Igniter Assembly and final machined. The Igniter Assembly is in final assembly and is being readied for testing in the October 2001 time frame. Test Plan dated August 2001, was revised and finalized, replacing Test Plan dated May 2001.

  3. A perfusion bioreactor system efficiently generates cell-loaded bone substitute materials for addressing critical size bone defects.

    PubMed

    Kleinhans, Claudia; Mohan, Ramkumar Ramani; Vacun, Gabriele; Schwarz, Thomas; Haller, Barbara; Sun, Yang; Kahlig, Alexander; Kluger, Petra; Finne-Wistrand, Anna; Walles, Heike; Hansmann, Jan

    2015-09-01

    Critical size bone defects and non-union fractions are still challenging to treat. Cell-loaded bone substitutes have shown improved bone ingrowth and bone formation. However, a lack of methods for homogenously colonizing scaffolds limits the maximum volume of bone grafts. Additionally, therapy robustness is impaired by heterogeneous cell populations after graft generation. Our aim was to establish a technology for generating grafts with a size of 10.5 mm in diameter and 25 mm of height, and thus for grafts suited for treatment of critical size bone defects. Therefore, a novel tailor-made bioreactor system was developed, allowing standardized flow conditions in a porous poly(L-lactide-co-caprolactone) material. Scaffolds were seeded with primary human mesenchymal stem cells derived from four different donors. In contrast to static experimental conditions, homogenous cell distributions were accomplished under dynamic culture. Additionally, culture in the bioreactor system allowed the induction of osteogenic lineage commitment after one week of culture without addition of soluble factors. This was demonstrated by quantitative analysis of calcification and gene expression markers related to osteogenic lineage. In conclusion, the novel bioreactor technology allows efficient and standardized conditions for generating bone substitutes that are suitable for the treatment of critical size defects in humans. PMID:26011163

  4. A perfusion bioreactor system efficiently generates cell‐loaded bone substitute materials for addressing critical size bone defects

    PubMed Central

    Kleinhans, Claudia; Mohan, Ramkumar Ramani; Vacun, Gabriele; Schwarz, Thomas; Haller, Barbara; Sun, Yang; Kahlig, Alexander; Kluger, Petra; Finne‐Wistrand, Anna; Walles, Heike

    2015-01-01

    Abstract Critical size bone defects and non‐union fractions are still challenging to treat. Cell‐loaded bone substitutes have shown improved bone ingrowth and bone formation. However, a lack of methods for homogenously colonizing scaffolds limits the maximum volume of bone grafts. Additionally, therapy robustness is impaired by heterogeneous cell populations after graft generation. Our aim was to establish a technology for generating grafts with a size of 10.5 mm in diameter and 25 mm of height, and thus for grafts suited for treatment of critical size bone defects. Therefore, a novel tailor‐made bioreactor system was developed, allowing standardized flow conditions in a porous poly(L‐lactide‐co‐caprolactone) material. Scaffolds were seeded with primary human mesenchymal stem cells derived from four different donors. In contrast to static experimental conditions, homogenous cell distributions were accomplished under dynamic culture. Additionally, culture in the bioreactor system allowed the induction of osteogenic lineage commitment after one week of culture without addition of soluble factors. This was demonstrated by quantitative analysis of calcification and gene expression markers related to osteogenic lineage. In conclusion, the novel bioreactor technology allows efficient and standardized conditions for generating bone substitutes that are suitable for the treatment of critical size defects in humans. PMID:26011163

  5. Thermal and Radiolytic Gas Generation in Hanford High-Level Waste

    SciTech Connect

    Bryan, Samuel A.; Pederson, Larry R.; King, C. M.

    2000-01-31

    The Hanford Site has 177 underground storage tanks containing radioactive wastes that are complex mixes of radioactive and chemical products. Some of these wastes are known to generate and retain large quantities of flammable gases consisting of hydrogen, nitrous oxide, nitrogen, and ammonia. Because these gases are flammable and have the potential for rapid release, the gas generation rate for each tank must be determined to establish the flammability hazard (Johnson et al. 1997). An understanding of gas generation is important to operation of the waste tanks for several reasons. First, knowledge of the overall rate of generation is needed to verify that any given tank has sufficient ventilation to ensure that flammable gases are maintained at a safe level within the dome space. Understanding the mechanisms for production of the various gases is important so that future waste operations do not create conditions that promote the production of hydrogen, ammonia, and nitrous oxide. Studying the generation of gases also provides important data for the composition of the gas mixture, which in turn is needed to assess the flammability characteristics. Finally, information about generation of gases, including the influence of various chemical constituents, temperature, and dose, would aid in assessing the future behavior of the waste during interim storage, implementation of controls, and final waste treatment. This paper summarizes the current knowledge of gas generation pathways and discusses models used in predicting gas generation rates from actual Hanford radioactive wastes. A comparison is made between measured gas generation rates and rates by the predictive models.

  6. New generation enrichment monitoring technology for gas centrifuge enrichment plants

    SciTech Connect

    Ianakiev, Kiril D; Alexandrov, Boian S.; Boyer, Brian D.; Hill, Thomas R.; Macarthur, Duncan W.; Marks, Thomas; Moss, Calvin E.; Sheppard, Gregory A.; Swinhoe, Martyn T.

    2008-06-13

    The continuous enrichment monitor, developed and fielded in the 1990s by the International Atomic Energy Agency, provided a go-no-go capability to distinguish between UF{sub 6} containing low enriched (approximately 4% {sup 235}U) and highly enriched (above 20% {sup 235}U) uranium. This instrument used the 22-keV line from a {sup 109}Cd source as a transmission source to achieve a high sensitivity to the UF{sub 6} gas absorption. The 1.27-yr half-life required that the source be periodically replaced and the instrument recalibrated. The instrument's functionality and accuracy were limited by the fact that measured gas density and gas pressure were treated as confidential facility information. The modern safeguarding of a gas centrifuge enrichment plant producing low-enriched UF{sub 6} product aims toward a more quantitative flow and enrichment monitoring concept that sets new standards for accuracy stability, and confidence. An instrument must be accurate enough to detect the diversion of a significant quantity of material, have virtually zero false alarms, and protect the operator's proprietary process information. We discuss a new concept for advanced gas enrichment assay measurement technology. This design concept eliminates the need for the periodic replacement of a radioactive source as well as the need for maintenance by experts. Some initial experimental results will be presented.

  7. Development of Micromachine Gas Turbine for Portable Power Generation

    NASA Astrophysics Data System (ADS)

    Isomura, Kousuke; Tanaka, Shuji; Togo, Shinichi; Kanebako, Hideki; Murayama, Motohide; Saji, Nobuyoshi; Sato, Fumihiro; Esashi, Masayoshi

    Micromachine gas turbine with centrifugal impellers of 10mm diameter fabricated by 5-axis micro-milling is under development at Tohoku University, in conjunction with Ishikawajima-Harima Heavy Industries Co., Ltd. (IHI), Tohoku-Gakuin University, and Sankyo Seiki Mfg. Co., Ltd. The development is currently at the stage of proving the feasibility of the gas turbine cycle by component tests. Micro-combustors have been developed for both hydrogen and methane fuel. Over 99.9% of the combustion efficiency has been realized in both combustors and the baseline configuration of the combustor for the gas turbine is set. A compressor of 10mm diameter has been developed as a micromachined turbocharger. The performance test of the micromachined turbocharger has been started, and ran up to 566000rpm, which is approximately 65% of the design speed. Compressor performance has been successfully measured along a constant speed line at 55% of the design speed.

  8. Potential role of gas hydrate decomposition in generating submarine slope failures: Chapter 12

    USGS Publications Warehouse

    Pauli, Charles K.; mUssler, William III; Dillon, William P.

    2003-01-01

    Gas hydrate decomposition is hypothesized to be a factor in generating weakness in continental margin sediments that may help explain some of the observed patterns of continental margin sediment instability. The processes associated with formation and decomposition of gas hydrate can cause the strengthening of sediments in which gas hydrate grow and the weakening of sediments in which gas hydrate decomposes. The weakened sediments may form horizons along which the potential for sediment failure is increased. While a causal relationship between slope failures and gas hydrate decomposition has not been proven, a number of empirical observations support their potential connection.

  9. Efficient gas lasers pumped by generators with inductive energy storage

    NASA Astrophysics Data System (ADS)

    Tarasenko, Victor F.; Panchenko, Alexei N.; Tel'minov, Alexei E.

    2008-05-01

    Laser and discharge parameters in mixtures of rare gases with halogens driven by a pre-pulse-sustainer circuit technique are studied. Inductive energy storage with semiconductor opening switch was used for the high-voltage pre-pulse formation. It was shown that the pre-pulse with a high amplitude and short rise-time along with sharp increase of discharge current and uniform UV- and x-ray preionization allow to form long-lived stable discharge in halogen containing gas mixtures. Improvement of both pulse duration and output energy was achieved for XeCl-, XeF-, KrCl- and KrF excimer lasers. Maximal laser output was as high as 1 J at efficiency up to 4%. Increase both of the radiation power and laser pulse duration were achieved in N2-NF3 (SF6) and He-F2 (NF3) gas mixtures, as well.

  10. Turbulence generated by a gas of electron acoustic solitons

    SciTech Connect

    Dubouloz, N.; Pottelette, R.; Malingre, M.; Treumann, R.A.

    1993-10-01

    The authors consider a gas of electron acoustic solitons propagating in a magnetized plasma, such as the auroral region. They show that such modes can exist, and propagate, and that the velocities and amplitudes of such waves, consistent with measured plasma density and temperature, are capable of explaining the high frequency part of the broadband electrostatic noise observed by the Viking satellite, which is in a spectral region forbidden to linear electrostatic waves.

  11. Gas Foil Bearings for Space Propulsion Nuclear Electric Power Generation

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.; DellaCorte, Christopher

    2006-01-01

    The choice of power conversion technology is critical in directing the design of a space vehicle for the future NASA mission to Mars. One candidate design consists of a foil bearing supported turbo alternator driven by a helium-xenon gas mixture heated by a nuclear reactor. The system is a closed-loop, meaning there is a constant volume of process fluid that is sealed from the environment. Therefore, foil bearings are proposed due to their ability to use the process gas as a lubricant. As such, the rotor dynamics of a foil bearing supported rotor is an important factor in the eventual design. The current work describes a rotor dynamic analysis to assess the viability of such a system. A brief technology background, assumptions, analyses, and conclusions are discussed in this report. The results indicate that a foil bearing supported turbo alternator is possible, although more work will be needed to gain knowledge about foil bearing behavior in helium-xenon gas.

  12. Effects of Globally Waste Disturbing Activities on Gas Generation, Retention, and Release in Hanford Waste Tanks

    SciTech Connect

    Stewart, Charles W.; Fountain, Matthew S.; Huckaby, James L.; Mahoney, Lenna A.; Meyer, Perry A.; Wells, Beric E.

    2005-08-02

    Various operations are authorized in Hanford single- and double-shell tanks that disturb all or a large fraction of the waste. These globally waste-disturbing activities have the potential to release a large fraction of the retained flammable gas and to affect future gas generation, retention, and release behavior. This report presents analyses of the expected flammable gas release mechanisms and the potential release rates and volumes resulting from these activities. The background of the flammable gas safety issue at Hanford is summarized, as is the current understanding of gas generation, retention, and release phenomena. Considerations for gas monitoring and assessment of the potential for changes in tank classification and steady-state flammability are given.

  13. Geothermal energy in the western United States and Hawaii: Resources and projected electricity generation supplies. [Contains glossary and address list of geothermal project developers and owners

    SciTech Connect

    Not Available

    1991-09-01

    Geothermal energy comes from the internal heat of the Earth, and has been continuously exploited for the production of electricity in the United States since 1960. Currently, geothermal power is one of the ready-to-use baseload electricity generating technologies that is competing in the western United States with fossil fuel, nuclear and hydroelectric generation technologies to provide utilities and their customers with a reliable and economic source of electric power. Furthermore, the development of domestic geothermal resources, as an alternative to fossil fuel combustion technologies, has a number of associated environmental benefits. This report serves two functions. First, it provides a description of geothermal technology and a progress report on the commercial status of geothermal electric power generation. Second, it addresses the question of how much electricity might be competitively produced from the geothermal resource base. 19 figs., 15 tabs.

  14. Gas generation mechanism due to electrolyte decomposition in commercial lithium-ion cell

    NASA Astrophysics Data System (ADS)

    Kumai, Kazuma; Miyashiro, Hajime; Kobayashi, Yo; Takei, Katsuhito; Ishikawa, Rikio

    To elucidate the gas generation mechanism due to electrolyte decomposition in commercial lithium-ion cells after long cycling, we developed a device which can accurately determine the volume of generated gas in the cell. Experiments on Li xC 6/Li 1- xCoO 2 cells using electrolytes such as 1 M LiPF 6 in propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are presented and discussed. In the nominal voltage range (4.2-2.5 V), compositional change due mainly to ester exchange reaction occurs, and gaseous products in the cell are little. Generated gas volume and compositional change in the electrolyte are detected largely in overcharged cells, and we discussed that gas generation due to electrolyte decomposition involves different decomposition reactions in overcharged and overdischarged cells.

  15. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: BIOQUELL, INC. CLARIS C HYDROGEN PEROXIDE GAS GENERATOR

    EPA Science Inventory

    The Environmental Technology Verification report discusses the technology and performance of the Clarus C Hydrogen Peroxide Gas Generator, a biological decontamination device manufactured by BIOQUELL, Inc. The unit was tested by evaluating its ability to decontaminate seven types...

  16. Generation and delivery device for ozone gas and ozone dissolved in water

    NASA Technical Reports Server (NTRS)

    Andrews, Craig C. (Inventor); Murphy, Oliver J. (Inventor)

    2004-01-01

    The present invention provides an ozone generation and delivery system that lends itself to small scale applications and requires very low maintenance. The system preferably includes an anode reservoir and a cathode phase separator each having a hydrophobic membrane to allow phase separation of produced gases from water. The hydrogen gas, ozone gas and water containing ozone may be delivered under pressure.

  17. Construction of power-generating gas turbine units with the use of efficient thermal schemes

    NASA Astrophysics Data System (ADS)

    Ermolenko, D. I.; Gusev, A. A.; Zhuravlev, Yu. I.; Lesnichenko, A. Ya.; Tsai, S. S.

    2008-08-01

    The design features of GTE-30 and GTE-50 power-generating gas turbines, the basic thermal circuit of a PGU-90 (150) combined-cycle plant, and a layout solution for a cogeneration station built around a gas-turbine unit are considered.

  18. Unknown exposures: gaps in basic characterization addressed with person-portable gas chromatography-mass spectrometry instrumentation.

    PubMed

    Smith, Philip A; Roe, Marc T A; Sadowski, Charles; Lee, Edgar D

    2011-03-01

    A newly developed person-portable gas chromatography-mass spectrometry (GC-MS) system was used to analyze several solvent standards, contact cement, paint thinner, and polychlorinated biphenyl samples. Passive solid phase microextraction sampling and fast chromatography with a resistively heated low thermal mass GC column were used. Results (combined sampling and analysis) were obtained in <2 min for solvent, contact cement, and paint thinner samples, and in <13 min for the polychlorinated biphenyl sample. Mass spectra produced by the small toroidal ion trap detector used were similar to those produced with heavily used transmission quadrupole mass spectrometers for polychlorinated biphenyl compounds, simple alkanes, and cycloalknes, while mass spectra for benzene and the ketone compounds analyzed showed evidence for ion/molecule reactions in the ion trap. For one of the contact cement samples analyzed, no evidence was found to indicate the presence of n-hexane, although the relevant material safety data sheet listed this ingredient. Specific chemical constituents corresponding to a potentially wide range of petroleum distillate compounds were identifiable from GC-MS analyses. The possibility for an improved basic characterization step in the exposure assessment process exists with the availability of fast, person-portable GC-MS, although work is needed to further refine this tool and understand the best ways it may be used. PMID:21318921

  19. Transition metal catalysis in the generation of petroleum and natural gas. Final report

    SciTech Connect

    Mango, F.D.

    1997-01-21

    This project originated on the premise that natural gas could be formed catalytically in the earth rather than thermally as commonly believed. The intention was to test this hypothetical view and to explore generally the role of sedimentary metals in the generation of light hydrocarbons (C1 - C9). We showed the metalliferous source rocks are indeed catalytic in the generation of natural gas. Various metal compounds in the pure state show the same levels of catalytic activity as sedimentary rocks and the products are identical. Nickel is particularly active among the early transition metals and is projected to remain catalytically robust at all stages of catagenesis. Nickel oxide promotes the formation of n-alkanes in addition to natural gas (NG), demonstrating the full scope of the hypothetical catalytic process: The composition of catalytic gas duplicates the entire range of natural gas, from so-called wet gas to dry gas (60 to 95+ wt % methane), while gas generated thermally is consistently depleted in methane (10 to 60 wt % methane). These results support the view that metal catalysis is a major pathway through which natural gas is formed in the earth.

  20. Keynote address

    SciTech Connect

    Pena, F.

    1999-07-01

    The author discusses the role of energy in the world economy, structural changes in the ever changing US energy sector and responses of the capital markets, and electric deregulation, highlighting the challenges facing the gas processors. He encourages the natural gas processors to continue to be aware of global forces which can rapidly affect the industry.

  1. Life Cycle Greenhouse Gas Emissions from Electricity Generation (Fact Sheet)

    SciTech Connect

    Not Available

    2013-01-01

    Analysts at NREL have developed and applied a systematic approach to review the LCA literature, identify primary sources of variability and, where possible, reduce variability in GHG emissions estimates through a procedure called 'harmonization.' Harmonization of the literature provides increased precision and helps clarify the impacts of specific electricity generation choices, producing more robust results.

  2. Accounting for fuel price risk: Using forward natural gas prices instead of gas price forecasts to compare renewable to natural gas-fired generation

    SciTech Connect

    Bolinger, Mark; Wiser, Ryan; Golove, William

    2003-08-13

    Against the backdrop of increasingly volatile natural gas prices, renewable energy resources, which by their nature are immune to natural gas fuel price risk, provide a real economic benefit. Unlike many contracts for natural gas-fired generation, renewable generation is typically sold under fixed-price contracts. Assuming that electricity consumers value long-term price stability, a utility or other retail electricity supplier that is looking to expand its resource portfolio (or a policymaker interested in evaluating different resource options) should therefore compare the cost of fixed-price renewable generation to the hedged or guaranteed cost of new natural gas-fired generation, rather than to projected costs based on uncertain gas price forecasts. To do otherwise would be to compare apples to oranges: by their nature, renewable resources carry no natural gas fuel price risk, and if the market values that attribute, then the most appropriate comparison is to the hedged cost of natural gas-fired generation. Nonetheless, utilities and others often compare the costs of renewable to gas-fired generation using as their fuel price input long-term gas price forecasts that are inherently uncertain, rather than long-term natural gas forward prices that can actually be locked in. This practice raises the critical question of how these two price streams compare. If they are similar, then one might conclude that forecast-based modeling and planning exercises are in fact approximating an apples-to-apples comparison, and no further consideration is necessary. If, however, natural gas forward prices systematically differ from price forecasts, then the use of such forecasts in planning and modeling exercises will yield results that are biased in favor of either renewable (if forwards < forecasts) or natural gas-fired generation (if forwards > forecasts). In this report we compare the cost of hedging natural gas price risk through traditional gas-based hedging instruments (e

  3. Three-dimensional unsteady flow calculations in an advanced gas generator turbine

    NASA Technical Reports Server (NTRS)

    Rangwalla, Akil A.

    1993-01-01

    This paper deals with the application of a three-dimensional, unsteady Navier-Stokes code for predicting the unsteady flow in a single stage of an advanced gas generator turbine. The numerical method solves the three-dimensional thin-layer Navier-Stokes equations, using a system of overlaid grids, which allow for relative motion between the rotor and stator airfoils. Results in the form of time averaged pressures and pressure amplitudes on the airfoil surfaces will be shown. In addition, instantaneous contours of pressure, Mach number, etc. will be presented in order to provide a greater understanding of the inviscid as well as the viscous aspects of the flowfield. Also, relevant secondary flow features such as cross-plane velocity vectors and total pressure contours will be presented. Prior work in two-dimensions has indicated that for the advanced designs, the unsteady interactions can play a significant role in turbine performance. These interactions affect not only the stage efficiency but can substantially alter the time-averaged features of the flow. This work is a natural extension of the work done in two-dimensions and hopes to address some of the issues raised by the two-dimensional calculations. These calculations are being performed as an integral part of an actual design process and demonstrate the value of unsteady rotor-stator interaction calculations in the design of turbomachines.

  4. FABRICATE AND TEST AN ADVANCED NON-POLLUTING TURBINE DRIVE GAS GENERATOR

    SciTech Connect

    Eugene Baxter; Roger E. Anderson; Stephen E. Doyle

    2003-06-01

    In September 2000 the Department of Energy's National Energy Technology Laboratory (DOE/NETL) contracted with Clean Energy Systems, Inc. (CES) of Sacramento, California to design, fabricate, and test a 20 MW{sub t} (10 MW{sub e}) gas generator. Program goals were to demonstrate a non-polluting gas generator at temperatures up to 3000 F at 1500 psi, and to demonstrate resulting drive gas composition, comprising steam and carbon dioxide substantially free of pollutants. Following hardware design and fabrication, testing, originally planned to begin in the summer of 2001, was delayed by unavailability of the contracted test facility. CES designed, fabricated, and tested the proposed gas generator as originally agreed. The CES process for producing near-zero-emissions power from fossil fuels is based on the near-stoichiometric combustion of a clean gaseous fuel with oxygen in the presence of recycled water, to produce a high-temperature, high-pressure turbine drive fluid comprising steam and carbon dioxide. Tests demonstrated igniter operation over the prescribed ranges of pressure and mixture ratios. Ignition was repeatable and reliable through more than 100 ignitions. Injector design ''A'' was operated successfully at both low power ({approx}20% of rated power) and at rated power ({approx}20 MW{sub t}) in more than 95 tests. The uncooled gas generator configuration (no diluent injectors or cooldown chambers installed) produced drive gases at temperatures approaching 3000 F and at pressures greater than 1550 psia. The fully cooled gas generator configuration, with cooldown chambers and injector ''A'', operated consistently at pressures from 1100 to 1540 psia and produced high pressure, steam-rich turbine drive gases at temperatures ranging from {approx}3000 to as low as 600 F. This report includes description of the intended next steps in the gas generator technology demonstration and traces the anticipated pathway to commercialization for the gas generator technology

  5. New-generation gas turbine helping brewery lighten energy costs

    SciTech Connect

    Brezonick, M.

    1994-10-01

    In nearly any manufacturing industry, the loss of electrical power can have a severe impact on the manufacturing process. The case of Labatt's Ontario Breweries in particular, the loss of electrical service puts a crimp in the brewmaster's art by forcing the company to dump large quantities of it's Labatt's Blue. To solve the problem, the company has installed a gas-turbine-drive cogeneration system to guard against brownout. The new 501-KB7 was developed from the well-established 501-KB5 turbine. It has improved power output over the 501-KB7 design, up from 4025 to 5225 kw, a higher 13.5:1 pressure ratio, and a 32% increased in airflow (20.4 kg/s). The Labatt's installation which became operational in 1993 reduced the Breweries energy cost because of 501-KB7 turbine's higher energy output. 3 figs.

  6. Magnetic Field Generation and Zonal Flows in the Gas Giants

    NASA Astrophysics Data System (ADS)

    Duarte, L.; Wicht, J.; Gastine, T.

    2013-12-01

    The surface dynamics of Jupiter and Saturn is dominated by a banded system of fierce zonal winds. The depth of these winds remains unclear but they are thought to be confined to the very outer envelopes where hydrogen remains molecular and the electrical conductivity is negligible. The dynamo responsible for the dipole dominated magnetic fields of both Gas Giants, on the other hand, likely operates in the deeper interior where hydrogen assumes a metallic state. We present numerical simulations that attempt to model both the zonal winds and the interior dynamo action in an integrated approach. Using the anelastic version of the MHD code MagIC, we explore the effects of density stratification and radial electrical conductivity variations. The electrical conductivity is assumed to remain constant in the thicker inner metallic region and decays exponentially towards the outer boundary throughout the molecular envelope. Our results show that the combination of stronger density stratification (Δρ≈55) and a weaker conducting outer layer is essential for reconciling dipole dominated dynamo action and a fierce equatorial zonal jet. Previous simulations with homogeneous electrical conductivity show that both are mutually exclusive, with solutions either having strong zonal winds and multipolar magnetic fields or weak zonal winds and dipole dominated magnetic fields. The particular setup explored here allows the equatorial jet to remain confined to the weaker conducting region where is does not interfere with the deeper seated dynamo action. The equatorial jet can afford to remain geostrophic and reaches throughout the whole shell. This is not an option for the additional mid to higher latitude jets, however. In dipole dominated dynamo solutions, appropriate for the Gas Giants, zonal flows remain very faint in the deeper dynamo region but increase in amplitude in the weakly conducting outer layer in some of our simulations. This suggests that the mid to high latitude jets

  7. Experimental studies on producer gas generation from wood waste in a downdraft biomass gasifier.

    PubMed

    Sheth, Pratik N; Babu, B V

    2009-06-01

    A process of conversion of solid carbonaceous fuel into combustible gas by partial combustion is known as gasification. The resulting gas, known as producer gas, is more versatile in its use than the original solid biomass. In the present study, a downdraft biomass gasifier is used to carry out the gasification experiments with the waste generated while making furniture in the carpentry section of the institute's workshop. Dalbergia sisoo, generally known as sesame wood or rose wood is mainly used in the furniture and wastage of the same is used as a biomass material in the present gasification studies. The effects of air flow rate and moisture content on biomass consumption rate and quality of the producer gas generated are studied by performing experiments. The performance of the biomass gasifier system is evaluated in terms of equivalence ratio, producer gas composition, calorific value of the producer gas, gas production rate, zone temperatures and cold gas efficiency. Material balance is carried out to examine the reliability of the results generated. The experimental results are compared with those reported in the literature. PMID:19231163

  8. Status and integration of studies of gas generation in Hanford wastes

    SciTech Connect

    Pederson, L.R.; Bryan, S.A.

    1996-10-01

    The purpose of this report is to review recent progress in determining the mechanism, kinetics, and stoichiometry of gas generation in Hanford waste tanks. Information has been gathered from the results of (1) laboratory studies with simulated wastes; (2) laboratory studies with actual waste core samples (Tanks SY-101 and SY-103); (3) studies of thermal and radiolytic reactions in the gas phase; (4) gas solubility evaluations; and (5) in-tank gas composition data. The results of laboratory studies using simulated wastes, which were aimed at determining chemical mechanisms responsible for gas generation, are summarized in Section 2. Emphasized are findings from work performed at the Georgia Institute of Technology (GIT), which was conducted under subcontract to Pacific Northwest National Laboratory (PNNL) and completed in FY 1996. Thermally activated pathways for the decomposition of hydroxyethylethylene-diaminetriacetic acid (HEDTA, trisodium salt) in simulated wastes were established by this work, among other accomplishments.

  9. Numerical study of the generation of runaway electrons in a gas diode with a hot channel

    SciTech Connect

    Lisenkov, V. V.; Shklyaev, V. A.

    2015-11-15

    A new method for increasing the efficiency of runaway electron beam generation in atmospheric pressure gas media has been suggested and theoretically proved. The method consists of creating a hot region (e.g., a spark channel or a laser plume) with a decreased numerical density of gas molecules (N) near the cathode. In this method, the ratio E/N (E—electric field strength) is increased by decreasing N instead of increasing E, as has been done in the past. The numerical model that is used allows the simultaneous calculation of the formation of a subnanosecond gas discharge and the generation of runaway electrons in gas media. The calculations have demonstrated the possibility of obtaining current pulses of runaway electrons with amplitudes of hundred of amperes and durations of more than 100 ps. The influence of the hot channel geometry on the parameters of the generated beam has been investigated.

  10. Molecular nitrogen in natural gas accumulations: Generation from sedimentary organic matter at high temperatures

    SciTech Connect

    Littke, R.; Krooss, B.; Frielingsdorf, J.; Idiz, E.

    1995-03-01

    The occurrence of natural gas accumulations with high percentages (up to 100%) of molecular nitrogen in various hydrocarbon provinces represents a largely unresolved problem and a serious exploration risk. In this context, a geochemical and basin modeling study was performed to evaluate the potential of sedimentary organic matter to generate molecular nitrogen. The masses of nitrogen present in coals - if converted into molecular nitrogen - are sufficient to fill commercial gas reservoirs. A calculation for gas accumulations in northern Germany, where percentages of molecular nitrogen range from less than 5 to greater than 90%, reveals that the molecular nitrogen generated in underlying coal-bearing strata is sufficient to account for the nitrogen gas even in the largest fields. In addition, much of the total nitrogen in clay-rich rock types, such as shales and mudstones, is fixed in sedimentary organic matter and may add to the nitrogen generation capacity of the coals.

  11. Effect of a falling gas-liquid absorption film temperature on entropy generation

    NASA Astrophysics Data System (ADS)

    Chermiti, Imen; Hidouri, Nejib; Brahim, Ammar Ben

    2013-08-01

    In this paper, an analytical study about the effect of a falling gas-liquid absorption film temperature on entropy generation is carried out. Entropy generation formulations due to viscous effects and mass transfer are derived. Results in terms of viscous, mass transfer and total irreversibilities are graphically presented and discussed.

  12. Consolidated, multimedia environmental review and licensing of a landfill gas combustion/electrical generation system in Maryland

    SciTech Connect

    Goldstein, D.R.; Brown, D.H.; Ross, J.B.; Mountain, P.D.

    1999-07-01

    To build a power plant or transmission line in the State of Maryland, a company must obtain a Certificate of Public Convenience and Necessity (CPCN) from the Maryland Public Service Commission (PSC). As part of this licensing process, applicants must address a full range of environmental, engineering, socioeconomic, planning, need, and cost issues. The CPCN constitutes permission to construct and operate the facility, and includes issuance of the required air quality and water appropriations permits. The Maryland Power Plant Research Program (PPRP) serves as the lead agency for the consolidated review of CPCN projects. A recent project in Maryland involved the beneficial use of collected landfill gas from a closed municipal solid waste landfill for the generation of up to 4 Megawatts (MW) of electricity. This electrical generation will be continuously fed into the existing transmission system under a power purchase agreement with the local power company. The project is unique is several aspects: the use of former Rolls Royce aircraft engines fitted with generator sets to produce electricity; the beneficial reuse of landfill gas which is currently being flared at the landfill; and the collaborative environmental review that was conducted for this project that resulted in a streamlined licensing approach. This paper will include: a description of the landfill gas combustion/electrical generation system; an explanation of the review process conducted for the project including New Source Review, ambient air impacts assessed through air dispersion modeling, noise generation impacts, and ecological impacts; background on power plant licensing in Maryland; and a discussion of how the collaborative approach led by PPRP proved to be proactive and environmentally beneficial.

  13. Design and construction of a thermophotovoltaic generator using turbine combustion gas

    SciTech Connect

    Erickson, T.A.; Lindler, K.W.; Harper, M.J.

    1997-07-01

    This US Naval Academy project involves the development of a prototype thermophotovoltaic (TPV) generator that uses a General Electric T-58 helicopter gas turbine as the heat source. The goals of this project were to demonstrate the viability of using TPV and external combustion gases to generate electricity, and develop a system which could also be used for materials testing. The generator was modularly designed so that different materials could be tested at a later date. The combustion gas was tapped from the T-58`s combustor through one of the two igniter ports and extracted through a silicon carbide matrix ceramic composite tube into a similarly constructed ceramic composite radiant emitter. The ceramic radiant emitters is heated by the combustion gas via convection, and then serves the TPV generator by radiating the heat outwards where it can be absorbed by thermophotovoltaic cells and converted directly into electricity. The gas turbine and generator module are monitored by a data acquisition system that performs both data collection and control functions. This paper details the design of the TPV generator. It also gives results of initial tests with the gas turbine.

  14. Drought Resilience of Water Supplies for Shale Gas Extraction and Related Power Generation in Texas

    NASA Astrophysics Data System (ADS)

    Reedy, R. C.; Scanlon, B. R.; Nicot, J. P.; Uhlman, K.

    2014-12-01

    There is considerable concern about water availability to support energy production in Texas, particularly considering that many of the shale plays are in semiarid areas of Texas and the state experienced the most extreme drought on record in 2011. The Eagle Ford shale play provides an excellent case study. Hydraulic fracturing water use for shale gas extraction in the play totaled ~ 12 billion gallons (bgal) in 2012, representing ~7 - 10% of total water use in the 16 county play area. The dominant source of water is groundwater which is not highly vulnerable to drought from a recharge perspective because water is primarily stored in the confined portion of aquifers that were recharged thousands of years ago. Water supply drought vulnerability results primarily from increased water use for irrigation. Irrigation water use in the Eagle Ford play was 30 billion gallons higher in the 2011 drought year relative to 2010. Recent trends toward increased use of brackish groundwater for shale gas extraction in the Eagle Ford also reduce pressure on fresh water resources. Evaluating the impacts of natural gas development on water resources should consider the use of natural gas in power generation, which now represents 50% of power generation in Texas. Water consumed in extracting the natural gas required for power generation is equivalent to ~7% of the water consumed in cooling these power plants in the state. However, natural gas production from shale plays can be overall beneficial in terms of water resources in the state because natural gas combined cycle power generation decreases water consumption by ~60% relative to traditional coal, nuclear, and natural gas plants that use steam turbine generation. This reduced water consumption enhances drought resilience of power generation in the state. In addition, natural gas combined cycle plants provide peaking capacity that complements increasing renewable wind generation which has no cooling water requirement. However, water

  15. Electrical Generation Using Non-Salable Low BTU Natural Gas

    SciTech Connect

    Scott Corsair

    2005-12-01

    High operating costs are a significant problem for independent operators throughout the U.S. Often, decisions to temporarily idle or abandon a well or lease are dictated by these cost considerations, which are often seen as unavoidable. Options for continuing operations on a marginal basis are limited, but must include non-conventional approaches to problem solving, such as the use of alternative sources of lease power, and scrupulous reduction of non-productive operating techniques and costs. The loss of access to marginal oil and gas productive reservoirs is of major concern to the DOE. The twin difficulties of high operating costs and low or marginal hydrocarbon production often force independent operators to temporarily or permanently abandon existing lease facilities, including producing wells. Producing well preservation, through continued economical operation of marginal wells, must be maintained. Reduced well and lease operating costs are expected to improve oil recovery of the Schaben field, in Ness County, Kansas, by several hundred thousands of barrels of oil. Appropriate technology demonstrated by American Warrior, allows the extension of producing well life and has application for many operators throughout the area.

  16. Solid waste generation from oil and gas industries in United Arab Emirates.

    PubMed

    Elshorbagy, Walid; Alkamali, Abdulqader

    2005-04-11

    Solid wastes generated from oil and gas industrial activities are very diverse in their characteristics, large in their amounts and many of which are hazardous in nature. Thus, quantifying and characterizing the generated amounts in association with their types, classes, sources, industrial activities, and their chemical and biological characteristics is an obvious mandate when evaluating the possible management practices. This paper discusses the types, amounts, generation units, and the factors related to solid waste generation from a major oil and gas field in the United Arab Emirates (Asab Field). The generated amounts are calculated based on a 1-year data collection survey and using a database software specially developed and customized for the current study. The average annual amount of total solid waste generated in the studied field is estimated at 4061 t. Such amount is found equivalent to 650 kg/capita, 0.37 kg/barrel oil, and 1.6 kg/m3 of extracted gas. The average annual amount of hazardous solid waste is estimated at 55 t and most of which (73%) is found to be generated from gas extraction-related activities. The majority of other industrial non-hazardous solid waste is generated from oil production-related activities (41%), The present analysis does also provide the estimated generation amounts per waste type and class, amounts of combustible, recyclable, and compostable wastes, and the amounts dumped in uncontrolled way as well as disposed into special hazardous landfill facilities. The results should help the decision makers in evaluating the best alternatives available to manage the solid wastes generated from the oil and gas industries. PMID:15811669

  17. Addressing core challenges for the next generation of type 2 translation research and systems: the translation science to population impact (TSci Impact) framework.

    PubMed

    Spoth, Richard; Rohrbach, Louise A; Greenberg, Mark; Leaf, Philip; Brown, C Hendricks; Fagan, Abigail; Catalano, Richard F; Pentz, Mary Ann; Sloboda, Zili; Hawkins, J David

    2013-08-01

    Evidence-based preventive interventions developed over the past two decades represent great potential for enhancing public health and well-being. Research confirming the limited extent to which these interventions have been broadly and effectively implemented, however, indicates much progress is needed to achieve population-level impact. In part, progress requires Type 2 translation research that investigates the complex processes and systems through which evidence-based interventions are adopted, implemented, and sustained on a large scale, with a strong orientation toward devising empirically-driven strategies for increasing their population impact. In this article, we address two core challenges to the advancement of T2 translation research: (1) building infrastructure and capacity to support systems-oriented scaling up of evidence-based interventions, with well-integrated practice-oriented T2 research, and (2) developing an agenda and improving research methods for advancing T2 translation science. We also summarize a heuristic "Translation Science to Population Impact (TSci Impact) Framework." It articulates key considerations in addressing the core challenges, with three components that represent: (1) four phases of translation functions to be investigated (pre-adoption, adoption, implementation, and sustainability); (2) the multiple contexts in which translation occurs, ranging from community to national levels; and (3) necessary practice and research infrastructure supports. Discussion of the framework addresses the critical roles of practitioner-scientist partnerships and networks, governmental agencies and policies at all levels, plus financing partnerships and structures, all required for both infrastructure development and advances in the science. The article concludes with two sets of recommended action steps that could provide impetus for advancing the next generation of T2 translation science and, in turn, potentially enhance the health and well

  18. Safety aspect concerning radiolytic gas generation in reactors.

    PubMed

    Ramshesh, V

    2001-01-01

    In water cooled and water moderated reactors (H2O in boiling water reactors/pressurised water reactors, D2O in pressurised heavy water reactors) during normal operation, radiolysis is a source of production of hydrogen/deuterium and oxygen. During the progress of a nuclear accident, while there are other important sources of hydrogen/deuterium, the oxygen availability can occur only through radiolysis or direct contact with air. In air saturated with water vapour at room temperature and pressure when H2/D2 concentration exceeds 4 vol % (a conservative estimate), a combustible mixture with oxygen can be formed. It is proposed to examine the basic principles of water radiolysis as far as they pertain to generation of H2/D2 and O2 and try to apply these concepts to reactors both under operating conditions and in accident situations. It is concluded that the possibility of an accident taking place through radiolysis is highly unlikely. PMID:11382138

  19. Evaluating the Climate Effects of Natural Gas Versus Coal Electricity Generation

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Myhrvold, N. P.; Caldeira, K.

    2014-12-01

    Assessing potential climate effects of fossil-fuel electricity generations, especially natural gas versus coal electricity generation is complicated by the large number of factors reported in life cycle assessment studies, compounded by the large number of proposed climate metrics. Thus, there is a need to identify the key factors affecting the climate effects of fossil-fuel electricity generations (especially natural gas and coal based electricity production), and to present these climate effects in as clear and transparent a way as possible. Here, we identify power plant efficiencies and methane emission rates as the factors that explain most of the variance in greenhouse gas emissions by natural gas and coal power plants. Thus, we focus on the roles of these factors in determining the relative merit of natural gas and coal power plants. We develop a simple model with estimating CH4 and CO2 emissions from natural gas and coal power plants and resulting climate effects. Simple underlying physical changes can be obscured by abstract evaluation metrics, thus we base our discussion on temperature changes over time. We find that, during the period of plant operation, if there is substantial natural gas leakage, natural gas plants can produce greater near-term warming than a coal plant with the same power output. However, if leakage rates can be made to be low and efficiency high, natural gas plants can produce some reduction in near-term warming. After several centuries of continuous use, natural gas power plants produce substantial warming, but in most cases substantially less warming than would occur with coal plants.

  20. Investigation of a catalytic gas generator for the Space Shuttle APU. [hydrazine Auxiliary Propulsion Unit

    NASA Technical Reports Server (NTRS)

    Emmons, D. L.; Huxtable, D. D.; Blevins, D. R.

    1974-01-01

    An investigation was conducted to establish the capability of a monopropellant hydrazine catalytic gas generator to meet the requirements specified for the Space Shuttle APU. Detailed analytical and experimental studies were conducted on potential problem areas including long-term nitriding effects on materials, design variables affecting catalyst life, vehicle vibration effects, and catalyst oxidation/contamination. A full-scale gas generator, designed to operate at a chamber pressure of 750 psia and a flow rate of 0.36 lbm/sec, was fabricated and subjected to three separate life test series. The objective of the first test series was to demonstrate the capability of the gas generator to successfully complete 20 simulated Space Shuttle missions in steady-state operation. The gas generator was then refurbished and subjected to a second series of tests to demonstrate the pulse-mode capability of the gas generator during 20 simulated missions. The third series of tests was conducted with a refurbished reactor to further demonstrate pulse-mode capability with a modified catalyst bed.

  1. GREENHOUSE GAS REDUCTION POTENTIAL WITH COMBINED HEAT AND POWER WITH DISTRIBUTED GENERATION PRIME MOVERS - ASME 2012

    SciTech Connect

    Curran, Scott; Theiss, Timothy J; Bunce, Michael

    2012-01-01

    Pending or recently enacted greenhouse gas regulations and mandates are leading to the need for current and feasible GHG reduction solutions including combined heat and power (CHP). Distributed generation using advanced reciprocating engines, gas turbines, microturbines and fuel cells has been shown to reduce greenhouse gases (GHG) compared to the U.S. electrical generation mix due to the use of natural gas and high electrical generation efficiencies of these prime movers. Many of these prime movers are also well suited for use in CHP systems which recover heat generated during combustion or energy conversion. CHP increases the total efficiency of the prime mover by recovering waste heat for generating electricity, replacing process steam, hot water for buildings or even cooling via absorption chilling. The increased efficiency of CHP systems further reduces GHG emissions compared to systems which do not recover waste thermal energy. Current GHG mandates within the U.S Federal sector and looming GHG legislation for states puts an emphasis on understanding the GHG reduction potential of such systems. This study compares the GHG savings from various state-of-the- art prime movers. GHG reductions from commercially available prime movers in the 1-5 MW class including, various industrial fuel cells, large and small gas turbines, micro turbines and reciprocating gas engines with and without CHP are compared to centralized electricity generation including the U.S. mix and the best available technology with natural gas combined cycle power plants. The findings show significant GHG saving potential with the use of CHP. Also provided is an exploration of the accounting methodology for GHG reductions with CHP and the sensitivity of such analyses to electrical generation efficiency, emissions factors and most importantly recoverable heat and thermal recovery efficiency from the CHP system.

  2. Micro- and Nanoscale Energetic Materials as Effective Heat Energy Sources for Enhanced Gas Generators.

    PubMed

    Kim, Sang Beom; Kim, Kyung Ju; Cho, Myung Hoon; Kim, Ji Hoon; Kim, Kyung Tae; Kim, Soo Hyung

    2016-04-13

    In this study, we systematically investigated the effect of micro- and nanoscale energetic materials in formulations of aluminum microparticles (Al MPs; heat source)/aluminum nanoparticles (Al NPs; heat source)/copper oxide nanoparticles (CuO NPs; oxidizer) on the combustion and gas-generating properties of sodium azide microparticles (NaN3 MPs; gas-generating agent) for potential applications in gas generators. The burn rate of the NaN3 MP/CuO NP composite powder was only ∼0.3 m/s. However, the addition of Al MPs and Al NPs to the NaN3 MP/CuO NP matrix caused the rates to reach ∼1.5 and ∼5.3 m/s, respectively. In addition, the N2 gas volume flow rate generated by the ignition of the NaN3 MP/CuO NP composite powder was only ∼0.6 L/s, which was significantly increased to ∼1.4 and ∼3.9 L/s by adding Al MPs and Al NPs, respectively, to the NaN3 MP/CuO NP composite powder. This suggested that the highly reactive Al MPs and NPs, with the assistance of CuO NPs, were effective heat-generating sources enabling the complete thermal decomposition of NaN3 MPs upon ignition. Al NPs were more effective than Al MPs in the gas generators because of the increased reactivity induced by the reduced particle size. Finally, we successfully demonstrated that a homemade airbag with a specific volume of ∼140 mL could be rapidly and fully inflated by the thermal activation of nanoscale energetic material-added gas-generating agents (i.e., NaN3 MP/Al NP/CuO NP composites) within the standard time of ∼50 ms for airbag inflation. PMID:27007287

  3. Addressing Misconceptions

    ERIC Educational Resources Information Center

    Dial, Katrina; Riddley, Diana; Williams, Kiesha; Sampson, Victor

    2009-01-01

    The law of conservation of mass can be counterintuitive for most students because they often think the mass of a substance is related to its physical state. As a result, students may hold a number of alternative conceptions related to this concept, including, for example, the believe that gas has no mass, that solids have greater mass than fluids,…

  4. Generation of ethylene tracer by noncatalytic pyrolysis of natural gas at elevated pressure

    USGS Publications Warehouse

    Lu, Y.; Chen, S.; Rostam-Abadi, M.; Ruch, R.; Coleman, D.; Benson, L.J.

    2005-01-01

    There is a critical need within the pipeline gas industry for an inexpensive and reliable technology to generate an identification tag or tracer that can be added to pipeline gas to identify gas that may escape and improve the deliverability and management of gas in underground storage fields. Ethylene is an ideal tracer, because it does not exist naturally in the pipeline gas, and because its physical properties are similar to the pipeline gas components. A pyrolysis process, known as the Tragen process, has been developed to continuously convert the ???2%-4% ethane component present in pipeline gas into ethylene at common pipeline pressures of 800 psi. In our studies of the Tragen process, pyrolysis without steam addition achieved a maximum ethylene yield of 28%-35% at a temperature range of 700-775 ??C, corresponding to an ethylene concentration of 4600-5800 ppm in the product gas. Coke deposition was determined to occur at a significant rate in the pyrolysis reactor without steam addition. The ?? 13C isotopic analysis of gas components showed a ?? 13C value of ethylene similar to ethane in the pipeline gas, indicating that most of the ethylene was generated from decomposition of the ethane in the raw gas. However, ?? 13C isotopic analysis of the deposited coke showed that coke was primarily produced from methane, rather than from ethane or other heavier hydrocarbons. No coke deposition was observed with the addition of steam at concentrations of > 20% by volume. The dilution with steam also improved the ethylene yield. ?? 2005 American Chemical Society.

  5. Continuous and Pulsed THz generation with molecular gas lasers and photoconductive antennas gated by femtosecond pulses

    NASA Astrophysics Data System (ADS)

    Cruz, Flavio C.; Nogueira, T.; Costa, Leverson F. L.; Jarschel, Paulo F.; Frateschi, Newton C.; Viscovini, Ronaldo C.; Vieira, Bruno R. B.; Guevara, Victor M. B.; Pereira, Daniel

    2008-04-01

    We report THz generation based on two systems: 1) continuous-wave (cw) laser generation in molecular gas lasers, and 2) short pulse generation in photoconductive antennas, gated by femtosecond near-infrared Ti:sapphire lasers. With the first system, we have generated tens of monochromatic cw laser lines over the last years, extending roughly from 40 microns to several hundred microns. This is done by optical pumping of gas lasers based on polar molecules such as methanol and its isotopes. In the second system, under development, pulsed THz radiation is generated by a photoconductive antenna built in a semi-insulating GaAs substrate excited by femtosecond pulses from a near-infrared (800 nm) Ti:sapphire laser.

  6. Recovery Act: Johnston Rhode Island Combined Cycle Electric Generating Plant Fueled by Waste Landfill Gas

    SciTech Connect

    Galowitz, Stephen

    2013-06-30

    The primary objective of the Project was to maximize the productive use of the substantial quantities of waste landfill gas generated and collected at the Central Landfill in Johnston, Rhode Island. An extensive analysis was conducted and it was determined that utilization of the waste gas for power generation in a combustion turbine combined cycle facility was the highest and best use. The resulting project reflected a cost effective balance of the following specific sub-objectives. 1) Meet environmental and regulatory requirements, particularly the compliance obligations imposed on the landfill to collect, process and destroy landfill gas. 2) Utilize proven and reliable technology and equipment. 3) Maximize electrical efficiency. 4) Maximize electric generating capacity, consistent with the anticipated quantities of landfill gas generated and collected at the Central Landfill. 5) Maximize equipment uptime. 6) Minimize water consumption. 7) Minimize post-combustion emissions. To achieve the Project Objective the project consisted of several components. 1) The landfill gas collection system was modified and upgraded. 2) A State-of-the Art gas clean up and compression facility was constructed. 3) A high pressure pipeline was constructed to convey cleaned landfill gas from the clean-up and compression facility to the power plant. 4) A combined cycle electric generating facility was constructed consisting of combustion turbine generator sets, heat recovery steam generators and a steam turbine. 5) The voltage of the electricity produced was increased at a newly constructed transformer/substation and the electricity was delivered to the local transmission system. The Project produced a myriad of beneficial impacts. 1) The Project created 453 FTE construction and manufacturing jobs and 25 FTE permanent jobs associated with the operation and maintenance of the plant and equipment. 2) By combining state-of-the-art gas clean up systems with post combustion emissions control

  7. Thermal analysis of a simple-cycle gas turbine in biogas power generation

    SciTech Connect

    Yomogida, D.E.; Thinh, Ngo Dinh

    1995-09-01

    This paper investigates the technical feasibility of utilizing small simple-cycle gas turbines (25 kW to 125 kW) for biogas power generation through thermal analysis. A computer code, GTPower, was developed to evaluate the performance of small simple-cycle gas turbines specifically for biogas combustion. The 125 KW Solar Gas Turbine (Tital series) has been selected as the base case gas turbine for biogas combustion. After its design parameters and typical operating conditions were entered into GTPower for analysis, GTPower outputted expected values for the thermal efficiency and specific work. For a sensitivity analysis, the GTPower Model outputted the thermal efficiency and specific work. For a sensitivity analysis, the GTPower Model outputted the thermal efficiency and specific work profiles for various operating conditions encountered in biogas combustion. These results will assist future research projects in determining the type of combustion device most suitable for biogas power generation.

  8. Microbial Gas Generation Under Expected Waste Isolation Pilot Plant Repository Conditions: Final Report

    SciTech Connect

    Gillow, J.B.; Francis, A.

    2011-07-01

    Gas generation from the microbial degradation of the organic constituents of transuranic (TRU) waste under conditions expected in the Waste Isolation Pilot Plant (WIPP) was investigated. The biodegradation of mixed cellulosic materials and electron-beam irradiated plastic and rubber materials (polyethylene, polyvinylchloride, hypalon, leaded hypalon, and neoprene) was examined. We evaluated the effects of environmental variables such as initial atmosphere (air or nitrogen), water content (humid ({approx}70% relative humidity, RH) and brine inundated), and nutrient amendments (nitogen phosphate, yeast extract, and excess nitrate) on microbial gas generation. Total gas production was determined by pressure measurement and carbon dioxide (CO{sub 2}) and methane (CH{sub 4}) were analyzed by gas chromatography; cellulose degradation products in solution were analyzed by high-performance liquid chromatography. Microbial populations in the samples were determined by direct microscopy and molecular analysis. The results of this work are summarized.

  9. Gas Generators and Their Potential to Support Human-Scale HIADS (Hypersonic Inflatable Aerodynamic Decelerators)

    NASA Technical Reports Server (NTRS)

    Bodkin, Richard J.; Cheatwood, F. M.; Dillman, Robert A; Dinonno, John M.; Hughes, Stephen J.; Lucy, Melvin H.

    2016-01-01

    As HIAD technology progresses from 3-m diameter experimental scale to as large as 20-m diameter for human Mars entry, the mass penalties of carrying compressed gas has led the HIAD team to research current state-of-the-art gas generator approaches. Summarized below are several technologies identified in this survey, along with some of the pros and cons with respect to supporting large-scale HIAD applications.

  10. Analytical investigation of thermal barrier coatings on advanced power generation gas turbines

    NASA Technical Reports Server (NTRS)

    Amos, D. J.

    1977-01-01

    An analytical investigation of present and advanced gas turbine power generation cycles incorporating thermal barrier turbine component coatings was performed. Approximately 50 parametric points considering simple, recuperated, and combined cycles (including gasification) with gas turbine inlet temperatures from current levels through 1644K (2500 F) were evaluated. The results indicated that thermal barriers would be an attractive means to improve performance and reduce cost of electricity for these cycles. A recommended thermal barrier development program has been defined.

  11. Quality Assurance Project Plan for the Gas Generation Testing Program at the INEL

    SciTech Connect

    1994-10-01

    The data quality objectives (DQOs) for the Program are to evaluate compliance with the limits on total gas generation rates, establish the concentrations of hydrogen and methane in the total gas flow, determine the headspace concentration of VOCs in each drum prior to the start of the test, and obtain estimates of the concentrations of several compounds for mass balance purposes. Criteria for the selection of waste containers at the INEL and the parameters that must be characterized prior to and during the tests are described. Collection of gaseous samples from 55-gallon drums of contact-handled transuranic waste for the gas generation testing is discussed. Analytical methods and calibrations are summarized. Administrative quality control measures described in this QAPjP include the generation, review, and approval of project documentation; control and retention of records; measures to ensure that personnel, subcontractors or vendors, and equipment meet the specifications necessary to achieve the required data quality for the project.

  12. CALCULATION OF DEMONSTRATION BULK VITRIFICATION SYSTEM MELTER INLEAKAGE AND OFF-GAS GENERATION RATE

    SciTech Connect

    MAY TH

    2008-04-16

    The River Protection Project (RPP) mission is to safely store, retrieve, treat, immobilize, and dispose of the Hanford Site tank waste. The Demonstration Bulk Vitrification System (DBVS) is a research and development project whose objective is to demonstrate the suitability of Bulk Vitrification treatment technology waste form for disposing of low-activity waste from the Tank Farms. The objective of this calculation is to determine the DBVS melter inleakage and off-gas generation rate based on full scale testing data from 38D. This calculation estimates the DBVS melter in leakage and gas generation rate based on test data. Inleakage is estimated before the melt was initiated, at one point during the melt, and at the end of the melt. Maximum gas generation rate is also estimated.

  13. Nondestructive Evaluation of the J-2X Direct Metal Laser Sintered Gas Generator Discharge Duct

    NASA Technical Reports Server (NTRS)

    Esther, Elizabeth A.; Beshears, Ronald D.; Lash, Rhonda K.

    2012-01-01

    The J-2X program at NASA's Marshall Space Flight Center (MSFC) procured a direct metal laser sintered (DMLS) gas generator discharge duct from Pratt & Whitney Rocketdyne and Morris Technologies for a test program that would evaluate the material properties and durability of the duct in an engine-like environment. DMLS technology was pursued as a manufacturing alternative to traditional techniques, which used off nominal practices to manufacture the gas generator duct's 180 degree turn geometry. MSFC's Nondestructive Evaluation (NDE) Team performed radiographic, ultrasonic, computed tomographic, and fluorescent penetrant examinations of the duct. Results from the NDE examinations reveal some shallow porosity but no major defects in the as-manufactured material. NDE examinations were also performed after hot-fire testing the gas generator duct and yielded similar results pre and post-test and showed no flaw growth or development.

  14. Multiple Exhaust Nozzle Effects on J-2X Gas Generator Outlet Impedance

    NASA Technical Reports Server (NTRS)

    Kenny, R. Jeremy; Muss, Jeffrey; Hulka, James R.; Casiano, Matthew

    2010-01-01

    The current test setup of the J-2X gas generator system uses a multiple nozzle configuration to exhaust hot gases to drive the propellant supply turbines. Combustion stability assessment of this gas generator design requires knowledge of the impedance effects the multiple nozzle configuration creates on the combustion chamber acoustic modes. Parallel work between NASA and Sierra Engineering is presented, showing two methods used to calculate the effective end impedance resulting from multiple nozzle configurations. The NASA method is a simple estimate of the effective impedance using the long wavelength approximation. Sierra Engineering has developed a more robust numerical integration method implemented in ROCCID to accommodate for multiple nozzles. Analysis using both methods are compared to J-2X gas generator test data collected over the past year.

  15. Addressing healthcare.

    PubMed

    Daly, Rich

    2013-02-11

    Though President Barack Obama has rarely made healthcare references in his State of the Union addresses, health policy experts are hoping he changes that strategy this year. "The question is: Will he say anything? You would hope that he would, given that that was the major issue he started his presidency with," says Dr. James Weinstein, left, of the Dartmouth-Hitchcock health system. PMID:23487896

  16. Spin Start Line Effects on the J2X Gas Generator Chamber Acoustics

    NASA Technical Reports Server (NTRS)

    Kenny, R. Jeremy

    2011-01-01

    The J2X Gas Generator engine design has a spin start line connected near to the turbine inlet vanes. This line provides helium during engine startup to begin turbomachinery operation. The spin start line also acts as an acoustic side branch which alters the chamber's acoustic modes. The side branch effectively creates 'split modes' in the chamber longitudinal modes, in particular below the first longitudinal mode and within the frequency range associated with the injection-coupled response of the Gas Generator. Interaction between the spin start-modified chamber acoustics and the injection-driven response can create a higher system response than without the spin start attached to the chamber. This work reviews the acoustic effects of the spin start line as seen throughout the workhorse gas generator test program. A simple impedance model of the spin start line is reviewed. Tests were run with no initial spin start gas existing in the line, as well as being initially filled with nitrogen gas. Tests were also run with varying spin start line lengths from 0" to 40". Acoustic impedance changes due to different spin start gas constituents and line lengths are shown. Collected thermocouple and static pressure data in the spin start line was used to help estimate the fluid properties along the line length. The side branch impedance model was coupled to a chamber impedance model to show the effects on the overall chamber response. Predictions of the spin start acoustic behavior for helium operation are shown and compared against available data.

  17. A computer model of gas generation and transport within TRU waste drums

    SciTech Connect

    Smith, F.G. III

    1988-06-01

    A computer model has been developed to predict radiolytic gas generation and transport within Transuranic (TRU) waste drums and surrounding enclosures. Gas generation from the radiolytic decomposition of organic material contaminated with plutonium is modeled and the concentrations of gas throughout the waste drum and enclosures are determined using a diffusional transport model. The model accurately reproduces experimentally measured gas concentrations. With polyethylene waste in unvented drums, the model predicts that the concentration of hydrogen gas can exceed 4 mole percent (lower flammable limit) with only about 5 curies of plutonium. If the drum liner is punctured and an unrestricted 0.75-in. carbon composite filter vent is installed in the drum lid, the plutonium loading can be increased to 240 Ci without generating flammable gas mixtures. Larger diameter filters can be used to increase the curie loading. The model has been used to show that shipments of 1000 Ci of plutonium-238 contaminated waste from Savannah River to the WIPP site are feasible using the TRUPACT shipping container. 10 refs., 17 figs., 6 tabs.

  18. Comprehensive Lifecycle Planning and Management System For Addressing Water Issues Associated With Shale Gas Development In New York, Pennsylvania, And West Virginia

    SciTech Connect

    Arthur, J. Daniel

    2012-07-01

    The objective of this project is to develop a modeling system to allow operators and regulators to plan all aspects of water management activities associated with shale gas development in the target project area of New York, Pennsylvania, and West Virginia (target area ), including water supply, transport, storage, use, recycling, and disposal and which can be used for planning, managing, forecasting, permit tracking, and compliance monitoring. The proposed project is a breakthrough approach to represent the entire shale gas water lifecycle in one comprehensive system with the capability to analyze impacts and options for operational efficiency and regulatory tracking and compliance, and to plan for future water use and disposition. It will address all of the major water-related issues of concern associated with shale gas development in the target area, including water withdrawal, transport, storage, use, treatment, recycling, and disposal. It will analyze the costs, water use, and wastes associated with the available options, and incorporate constraints presented by permit requirements, agreements, local and state regulations, equipment and material availability, etc. By using the system to examine the water lifecycle from withdrawals through disposal, users will be able to perform scenario analysis to answer "what if" questions for various situations. The system will include regulatory requirements of the appropriate state and regional agencies and facilitate reporting and permit applications and tracking. These features will allow operators to plan for more cost effective resource production. Regulators will be able to analyze impacts of development over an entire area. Regulators can then make informed decisions about the protections and practices that should be required as development proceeds. This modeling system will have myriad benefits for industry, government, and the public. For industry, it will allow planning all water management operations for a

  19. A decision support tool for landfill methane generation and gas collection.

    PubMed

    Emkes, Harriet; Coulon, Frédéric; Wagland, Stuart

    2015-09-01

    This study presents a decision support tool (DST) to enhance methane generation at individual landfill sites. To date there is no such tool available to provide landfill decision makers with clear and simplified information to evaluate biochemical processes within a landfill site, to assess performance of gas production and to identify potential remedies to any issues. The current lack in understanding stems from the complexity of the landfill waste degradation process. Two scoring sets for landfill gas production performance are calculated with the tool: (1) methane output score which measures the deviation of the actual methane output rate at each site which the prediction generated by the first order decay model LandGEM; and (2) landfill gas indicators' score, which measures the deviation of the landfill gas indicators from their ideal ranges for optimal methane generation conditions. Landfill gas indicators include moisture content, temperature, alkalinity, pH, BOD, COD, BOD/COD ratio, ammonia, chloride, iron and zinc. A total landfill gas indicator score is provided using multi-criteria analysis to calculate the sum of weighted scores for each indicator. The weights for each indicator are calculated using an analytical hierarchical process. The tool is tested against five real scenarios for landfill sites in UK with a range of good, average and poor landfill methane generation over a one year period (2012). An interpretation of the results is given for each scenario and recommendations are highlighted for methane output rate enhancement. Results demonstrate how the tool can help landfill managers and operators to enhance their understanding of methane generation at a site-specific level, track landfill methane generation over time, compare and rank sites, and identify problems areas within a landfill site. PMID:26168873

  20. Corrosion-induced gas generation in a nuclear waste repository: Reactive geochemistry and multiphase flow effect

    SciTech Connect

    Xu, T.; Senger, R.; Finsterle, S.

    2008-10-15

    Corrosion of steel canisters, stored in a repository for spent fuel and high-level nuclear wastes, leads to the generation and accumulation of hydrogen gas in the backfilled emplacement tunnels, which may significantly affect long-term repository safety. Previous studies used H{sub 2} generation rates based on the volume of the waste or canister material and the stoichiometry of the corrosion reaction. However, iron corrosion and H{sub 2} generation rates vary with time, depending on factors such as amount of iron, water availability, water contact area, and aqueous and solid chemistry. To account for these factors and feedback mechanisms, we developed a chemistry model related to iron corrosion, coupled with two-phase (liquid and gas) flow phenomena that are driven by gas-pressure buildup associated with H{sub 2} generation and water consumption. Results indicate that by dynamically calculating H{sub 2} generation rates based on a simple model of corrosion chemistry, and by coupling this corrosion reaction with two-phase flow processes, the degree and extent of gas pressure buildup could be much smaller compared to a model that neglects the coupling between flow and reactive transport mechanisms. By considering the feedback of corrosion chemistry, the gas pressure increases initially at the canister, but later decreases and eventually returns to a stabilized pressure that is slightly higher than the background pressure. The current study focuses on corrosion under anaerobic conditions for which the coupled hydrogeochemical model was used to examine the role of selected physical parameters on the H{sub 2} gas generation and corresponding pressure buildup in a nuclear waste repository. The developed model can be applied to evaluate the effect of water and mineral chemistry of the buffer and host rock on the corrosion reaction for future site-specific studies.

  1. Gas generation from low-level radioactive waste: Concerns for disposal

    SciTech Connect

    Siskind, B.

    1992-04-01

    The Advisory Committee on Nuclear Waste (ACNW) has urged the Nuclear Regulatory Commission (NRC) to reexamine the topic of hydrogen gas generation from low-level radioactive waste (LLW) in closed spaces to ensure that the slow buildup of hydrogen from water-bearing wastes in sealed containers does not become a problem for long-term safe disposal. Brookhaven National Laboratory (BNL) has prepared a report, summarized in this paper, for the NRC to respond to these concerns. The paper discusses the range of values for G(H{sub 2}) reported for materials of relevance to LLW disposal; most of these values are in the range of 0.1 to 0.6. Most studies of radiolytic hydrogen generation indicate a leveling off of pressurization, probably because of chemical kinetics involving, in many cases, the radiolysis of water within the waste. Even if no leveling off occurs, realistic gas leakage rates (indicating poor closure by gaskets on drums and liners) will result in adequate relief of pressure for radiolytic gas generation from the majority of commercial sector LLW packages. Biodegradative gas generation, however, could pose a pressurization hazard even at realistic gas leakage rates. Recommendations include passive vents on LLW containers (as already specified for high integrity containers) and upper limits to the G values and/or the specific activity of the LLW.

  2. Gas generation from low-level radioactive waste: Concerns for disposal

    SciTech Connect

    Siskind, B.

    1992-01-01

    The Advisory Committee on Nuclear Waste (ACNW) has urged the Nuclear Regulatory Commission (NRC) to reexamine the topic of hydrogen gas generation from low-level radioactive waste (LLW) in closed spaces to ensure that the slow buildup of hydrogen from water-bearing wastes in sealed containers does not become a problem for long-term safe disposal. Brookhaven National Laboratory (BNL) has prepared a report, summarized in this paper, for the NRC to respond to these concerns. The paper discusses the range of values for G(H{sub 2}) reported for materials of relevance to LLW disposal; most of these values are in the range of 0.1 to 0.6. Most studies of radiolytic hydrogen generation indicate a leveling off of pressurization, probably because of chemical kinetics involving, in many cases, the radiolysis of water within the waste. Even if no leveling off occurs, realistic gas leakage rates (indicating poor closure by gaskets on drums and liners) will result in adequate relief of pressure for radiolytic gas generation from the majority of commercial sector LLW packages. Biodegradative gas generation, however, could pose a pressurization hazard even at realistic gas leakage rates. Recommendations include passive vents on LLW containers (as already specified for high integrity containers) and upper limits to the G values and/or the specific activity of the LLW.

  3. Genetic algorithm to optimize the design of main combustor and gas generator in liquid rocket engines

    NASA Astrophysics Data System (ADS)

    Son, Min; Ko, Sangho; Koo, Jaye

    2014-06-01

    A genetic algorithm was used to develop optimal design methods for the regenerative cooled combustor and fuel-rich gas generator of a liquid rocket engine. For the combustor design, a chemical equilibrium analysis was applied, and the profile was calculated using Rao's method. One-dimensional heat transfer was assumed along the profile, and cooling channels were designed. For the gas-generator design, non-equilibrium properties were derived from a counterflow analysis, and a vaporization model for the fuel droplet was adopted to calculate residence time. Finally, a genetic algorithm was adopted to optimize the designs. The combustor and gas generator were optimally designed for 30-tonf, 75-tonf, and 150-tonf engines. The optimized combustors demonstrated superior design characteristics when compared with previous non-optimized results. Wall temperatures at the nozzle throat were optimized to satisfy the requirement of 800 K, and specific impulses were maximized. In addition, the target turbine power and a burned-gas temperature of 1000 K were obtained from the optimized gas-generator design.

  4. Generation and delivery device for ozone gas and ozone dissolved in water

    NASA Technical Reports Server (NTRS)

    Andrews, Craig C. (Inventor); Rogers, Thomas D. (Inventor); Murphy, Oliver J. (Inventor)

    1999-01-01

    The present invention provides an ozone generation and delivery system that lends itself to small scale applications and requires very low maintenance. The system includes an anode reservoir and a cathode phase separator each having a hydrophobic membrane to allow phase separation of produced gases from water. The system may be configured to operate passively with no moving parts or in a self-pressurizing manner with the inclusion of a pressure controlling device or valve in the gas outlet of the anode reservoir. The hydrogen gas, ozone gas and water containing ozone may be delivered under pressure.

  5. Generation and delivery device for ozone gas and ozone dissolved in water

    NASA Technical Reports Server (NTRS)

    Andrews, Craig C. (Inventor); Murphy, Oliver J. (Inventor)

    2006-01-01

    The present invention provides an ozone generation and delivery system that lends itself to small scale applications and requires very low maintenance. The system includes an anode reservoir and a cathode phase separator each having a hydrophobic membrane to allow phase separation of produced gases from water. The system may be configured to operate passively with no moving parts or in a self-pressurizing manner with the inclusion of a pressure controlling device or valve in the gas outlet of the anode reservoir. The hydrogen gas, ozone gas and water containing ozone may be delivered under pressure.

  6. Advances in Thermal Spray Coatings for Gas Turbines and Energy Generation: A Review

    NASA Astrophysics Data System (ADS)

    Hardwicke, Canan U.; Lau, Yuk-Chiu

    2013-06-01

    Functional coatings are widely used in energy generation equipment in industries such as renewables, oil and gas, propulsion engines, and gas turbines. Intelligent thermal spray processing is vital in many of these areas for efficient manufacturing. Advanced thermal spray coating applications include thermal management, wear, oxidation, corrosion resistance, sealing systems, vibration and sound absorbance, and component repair. This paper reviews the current status of materials, equipment, processing, and properties' aspects for key coatings in the energy industry, especially the developments in large-scale gas turbines. In addition to the most recent industrial advances in thermal spray technologies, future technical needs are also highlighted.

  7. Development of the Next Generation Gas Trap for the Space Station Internal Thermal Control System

    NASA Technical Reports Server (NTRS)

    Leimkuehler, Thomas O.; Spelbring, Chris; Reeves, Daniel R.; Holt, James M.

    2003-01-01

    The current dual-membrane gas trap is designed to remove non-condensed gases (NCG) from the Internal Thermal Control System (ITCS) coolant on board the International Space Station (ISS). To date it has successfully served its purpose of preventing depriming, overspeed, and shutdown of the ITCS pump. However, contamination in the ITCS coolant has adversely affected the gas venting rate and lifetime of the gas trap, warranting a development effort for a next-generation gas trap. Design goals are to meet or exceed the current requirements to (1) include greater operating ranges and conditions, (2) eliminate reliance on the current hydrophilic tube fabrication process, and (3) increase operational life and tolerance to particulate and microbial growth fouling. In addition, the next generation gas trap will essentially be a 'dropin" design such that no modifications to the ITCS pump package assembly (PPA) will be required, and the implementation of the new design will not affect changes to the ITCS operational conditions, interfaces, or software. This paper will present the initial membrane module design and development work which has included (1) a trade study among several conceptual designs, (2) performance modeling of a hydrophobic-only design, and (3) small-scale development test data for the hydrophobic-only design. Testing has shown that the hydrophobic-only design is capable of performing even better than the current dual-membrane design for both steady-state gas removal and gas slug removal.

  8. Optimal Capacity and Location Assessment of Natural Gas Fired Distributed Generation in Residential Areas

    NASA Astrophysics Data System (ADS)

    Khalil, Sarah My

    With ever increasing use of natural gas to generate electricity, installed natural gas fired microturbines are found in residential areas to generate electricity locally. This research work discusses a generalized methodology for assessing optimal capacity and locations for installing natural gas fired microturbines in a distribution residential network. The overall objective is to place microturbines to minimize the system power loss occurring in the electrical distribution network; in such a way that the electric feeder does not need any up-gradation. The IEEE 123 Node Test Feeder is selected as the test bed for validating the developed methodology. Three-phase unbalanced electric power flow is run in OpenDSS through COM server, and the gas distribution network is analyzed using GASWorkS. The continual sensitivity analysis methodology is developed to select multiple DG locations and annual simulation is run to minimize annual average losses. The proposed placement of microturbines must be feasible in the gas distribution network and should not result into gas pipeline reinforcement. The corresponding gas distribution network is developed in GASWorkS software, and nodal pressures of the gas system are checked for various cases to investigate if the existing gas distribution network can accommodate the penetration of selected microturbines. The results indicate the optimal locations suitable to place microturbines and capacity that can be accommodated by the system, based on the consideration of overall minimum annual average losses as well as the guarantee of nodal pressure provided by the gas distribution network. The proposed method is generalized and can be used for any IEEE test feeder or an actual residential distribution network.

  9. Hydrogen gas generation from refuse-derived fuel (RDF) under wet conditions.

    PubMed

    Sakka, Makiko; Kimura, Tetsuya; Sakka, Kazuo; Ohmiya, Kunio

    2004-02-01

    An explosion has recently occurred at a silo containing refuse-derived fuels (RDF) in Japan. There is a possibility that microorganisms are involved in generation of combustible gas from RDF and this study was aimed at showing the presence of bacteria that can ferment RDF pellets. All RDF samples tested contained a relatively high number of viable bacterial cells, 1.4x10(5) to 3.2x10(6) viable cells/g. These bacteria in the RDF samples fermented them to generate heat and hydrogen gas. PMID:14981319

  10. Life Cycle GHG Emissions from Conventional Natural Gas Power Generation: Systematic Review and Harmonization (Presentation)

    SciTech Connect

    Heath, G.; O'Donoughue, P.; Whitaker, M.

    2012-12-01

    This research provides a systematic review and harmonization of the life cycle assessment (LCA) literature of electricity generated from conventionally produced natural gas. We focus on estimates of greenhouse gases (GHGs) emitted in the life cycle of electricity generation from conventionally produced natural gas in combustion turbines (NGCT) and combined-cycle (NGCC) systems. A process we term "harmonization" was employed to align several common system performance parameters and assumptions to better allow for cross-study comparisons, with the goal of clarifying central tendency and reducing variability in estimates of life cycle GHG emissions. This presentation summarizes preliminary results.

  11. Laboratory and theoretical constraints on the generation and composition of natural gas

    NASA Astrophysics Data System (ADS)

    Seewald, Jeffrey S.; Benitez-Nelson, Bryan C.; Whelan, Jean K.

    1998-05-01

    Hydrous pyrolysis experiments were conducted at 125 to 375°C and 350 bars to constrain factors that regulate the generation and relative abundance of hydrocarbon and nonhydrocarbon gases during thermal maturation of Monterey, Eutaw, and Smackover shale. Thermogenic gas was generated at temperatures as low as 125°C and increased in abundance with increasing temperature. The relative abundance of individual hydrocarbons varied substantially in response to increasing time and temperature reflecting the chemical processes responsible for their formation. The hydrocarbon fraction of low maturity gas produced via primary cracking of kerogen was composed predominantly of methane. With increasing thermal maturity, the onset of bitumen generation produced longer-chain hydrocarbons causing a decrease in the relative abundance of methane. At high levels of thermal maturity, the absolute and relative abundance of methane increased due to decomposition of bitumen. In all experiments at all temperatures, carbon dioxide was the most abundant volatile organic alteration product. Carbon dioxide was produced directly from kerogen at low thermal maturity and via the decomposition of bitumen and/or kerogen at high thermal maturity. During early stage alteration, kerogen likely represents the dominant source of oxygen in carbon dioxide while at high thermal maturities water may represent an abundant and reactive oxygen source. Hydrogen released during the disproportionation of water is likely consumed during hydrocarbon generation. Theoretical reaction path modeling suggests that the precipitation of calcite may effectively remove carbon dioxide from natural gas if a source of Ca is available within the rock. Thus, carbon dioxide-rich natural gas may be relatively pristine while methane-rich natural gas may reflect the occurrence of secondary reactions involving inorganic sedimentary components. Kinetic analysis of the experimental data indicates a narrow range of activation energies

  12. Next Generation Pressurized Oxy-Coal Combustion: High Efficiency and No Flue Gas Recirculation

    SciTech Connect

    Rue, David

    2013-09-30

    The Gas Technology Institute (GTI) has developed a pressurized oxy-coal fired molten bed boiler (MBB) concept, in which coal and oxygen are fired directly into a bed of molten coal slag through burners located on the bottom of the boiler and fired upward. Circulation of heat by the molten slag eliminates the need for a flue gas recirculation loop and provides excellent heat transfer to steam tubes in the boiler walls. Advantages of the MBB technology over other boilers include higher efficiency (from eliminating flue gas recirculation), a smaller and less expensive boiler, modular design leading to direct scalability, decreased fines carryover and handling costs, smaller exhaust duct size, and smaller emissions control equipment sizes. The objective of this project was to conduct techno-economic analyses and an engineering design of the MBB project and to support this work with thermodynamic analyses and oxy-coal burner testing. Techno-economic analyses of GTI’s pressurized oxy-coal fired MBB technology found that the overall plant with compressed CO2 has an efficiency of 31.6%. This is a significant increase over calculated 29.2% efficiency of first generation oxy-coal plants. Cost of electricity (COE) for the pressurized MBB supercritical steam power plant with CO2 capture and compression was calculated to be 134% of the COE for an air-coal supercritical steam power plant with no CO2 capture. This compares positively with a calculated COE for first generation oxy-coal supercritical steam power plants with CO2 capture and compression of 164%. The COE for the MBB power plant is found to meet the U.S. Department of Energy (DOE) target of 135%, before any plant optimization. The MBB power plant was also determined to be simpler than other oxy-coal power plants with a 17% lower capital cost. No other known combustion technology can produce higher efficiencies or lower COE when CO2 capture and compression are included. A thermodynamic enthalpy and exergy analysis

  13. Recovery Act: Brea California Combined Cycle Electric Generating Plant Fueled by Waste Landfill Gas

    SciTech Connect

    Galowitz, Stephen

    2012-12-31

    The primary objective of the Project was to maximize the productive use of the substantial quantities of waste landfill gas generated and collected at the Olinda Landfill near Brea, California. An extensive analysis was conducted and it was determined that utilization of the waste gas for power generation in a combustion turbine combined cycle facility was the highest and best use. The resulting Project reflected a cost effective balance of the following specific sub-objectives: • Meeting the environmental and regulatory requirements, particularly the compliance obligations imposed on the landfill to collect, process and destroy landfill gas • Utilizing proven and reliable technology and equipment • Maximizing electrical efficiency • Maximizing electric generating capacity, consistent with the anticipated quantities of landfill gas generated and collected at the Olinda Landfill • Maximizing equipment uptime • Minimizing water consumption • Minimizing post-combustion emissions • The Project produced and will produce a myriad of beneficial impacts. o The Project created 360 FTE construction and manufacturing jobs and 15 FTE permanent jobs associated with the operation and maintenance of the plant and equipment. o By combining state-of-the-art gas clean up systems with post combustion emissions control systems, the Project established new national standards for best available control technology (BACT). o The Project will annually produce 280,320 MWh’s of clean energy o By destroying the methane in the landfill gas, the Project will generate CO2 equivalent reductions of 164,938 tons annually. The completed facility produces 27.4 MWnet and operates 24 hours a day, seven days a week.

  14. Modeling of gas generation from the Cameo coal zone in the Piceance Basin Colorado

    SciTech Connect

    Zhang, E.; Hill, R.J.; Katz, B.J.; Tang, Y.C.

    2008-08-15

    The gas generative potential of the Cretaceous Cameo coal in the Piceance Basin, northwestern Colorado, was evaluated quantitatively by sealed gold tube pyrolysis. The H/C and O/C elemental ratios show that pyrolyzed Cameo coal samples follow the Van Krevelen humic coal evolution pathway, reasonably simulating natural coal maturation. Kinetic parameters (activation energy and frequency factor) for gas generation and vitrinite reflectance (R{sub o}) changes were calculated from pyrolysis data. Experimental R{sub o} results from this study are not adequately predicted by published R{sub o} kinetics and indicate the necessity of deriving basin-specific kinetic parameters when building predictive basin models. Using derived kinetics for R{sub o}, evolution and gas generation, basin modeling was completed for 57 wells across the Piceance Basin, which enabled the mapping of coal-rank and coalbed gas potential. Quantities of methane generated at approximately 1.2% R{sub o} are about 300 standard cubic feet per ton (scf/ton) and more than 2500 scf/ton (in-situ dry-ash-free coal) at R{sub o}, values reaching 1.9%. Gases generated in both low- and high-maturity coals are less wet, whereas the wetter gas is expected where R{sub o} is approximately 1.4-1.5%. As controlled by regional coal rank and net coal thickness, the largest in-place coalbed gas resources are located in the central part of the basin, where predicted volumes exceed 150 bcf/mi, excluding gases in tight sands.

  15. Evaluating transition-metal catalysis in gas generation from the Permian Kupferschiefer by hydrous pyrolysis

    USGS Publications Warehouse

    Lewan, M.D.; Kotarba, M.J.; Wieclaw, D.; Piestrzynski, A.

    2008-01-01

    Transition metals in source rocks have been advocated as catalysts in determining extent, composition, and timing of natural gas generation (Mango, F. D. (1996) Transition metal catalysis in the generation of natural gas. Org. Geochem.24, 977–984). This controversial hypothesis may have important implications concerning gas generation in unconventional shale-gas accumulations. Although experiments have been conducted to test the metal-catalysis hypothesis, their approach and results remain equivocal in evaluating natural assemblages of transition metals and organic matter in shale. The Permian Kupferschiefer of Poland offers an excellent opportunity to test the hypothesis with immature to marginally mature shale rich in both transition metals and organic matter. Twelve subsurface samples containing similar Type-II kerogen with different amounts and types of transition metals were subjected to hydrous pyrolysis at 330° and 355 °C for 72 h. The gases generated in these experiments were quantitatively collected and analyzed for molecular composition and stable isotopes. Expelled immiscible oils, reacted waters, and spent rock were also quantitatively collected. The results show that transition metals have no effect on methane yields or enrichment. δ13C values of generated methane, ethane, propane and butanes show no systematic changes with increasing transition metals. The potential for transition metals to enhance gas generation and oil cracking was examined by looking at the ratio of the generated hydrocarbon gases to generated expelled immiscible oil (i.e., GOR), which showed no systematic change with increasing transition metals. Assuming maximum yields at 355 °C for 72 h and first-order reaction rates, pseudo-rate constants for methane generation at 330 °C were calculated. These rate constants showed no increase with increasing transition metals. The lack of a significant catalytic effect of transition metals on the extent, composition, and timing of

  16. Evaluating transition-metal catalysis in gas generation from the Permian Kupferschiefer by hydrous pyrolysis

    NASA Astrophysics Data System (ADS)

    Lewan, M. D.; Kotarba, M. J.; Więcław, D.; Piestrzyński, A.

    2008-08-01

    Transition metals in source rocks have been advocated as catalysts in determining extent, composition, and timing of natural gas generation (Mango, F. D. (1996) Transition metal catalysis in the generation of natural gas. Org. Geochem.24, 977-984). This controversial hypothesis may have important implications concerning gas generation in unconventional shale-gas accumulations. Although experiments have been conducted to test the metal-catalysis hypothesis, their approach and results remain equivocal in evaluating natural assemblages of transition metals and organic matter in shale. The Permian Kupferschiefer of Poland offers an excellent opportunity to test the hypothesis with immature to marginally mature shale rich in both transition metals and organic matter. Twelve subsurface samples containing similar Type-II kerogen with different amounts and types of transition metals were subjected to hydrous pyrolysis at 330° and 355 °C for 72 h. The gases generated in these experiments were quantitatively collected and analyzed for molecular composition and stable isotopes. Expelled immiscible oils, reacted waters, and spent rock were also quantitatively collected. The results show that transition metals have no effect on methane yields or enrichment. δ 13C values of generated methane, ethane, propane and butanes show no systematic changes with increasing transition metals. The potential for transition metals to enhance gas generation and oil cracking was examined by looking at the ratio of the generated hydrocarbon gases to generated expelled immiscible oil (i.e., GOR), which showed no systematic change with increasing transition metals. Assuming maximum yields at 355 °C for 72 h and first-order reaction rates, pseudo-rate constants for methane generation at 330 °C were calculated. These rate constants showed no increase with increasing transition metals. The lack of a significant catalytic effect of transition metals on the extent, composition, and timing of

  17. 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.

  18. Method for generating a highly reactive plasma for exhaust gas aftertreatment and enhanced catalyst reactivity

    DOEpatents

    Whealton, John H.; Hanson, Gregory R.; Storey, John M.; Raridon, Richard J.; Armfield, Jeffrey S.; Bigelow, Timothy S.; Graves, Ronald L.

    2001-01-01

    A method for non-thermal plasma aftertreatment of exhaust gases the method comprising the steps of providing short risetime (about 40 ps), high frequency (about 5G hz), high power bursts of low-duty factor microwaves sufficient to generate a dielectric barrier discharge and passing a gas to treated through the discharge so as to cause dissociative reduction of the exhaust gases. The invention also includes a reactor for generating the non-thermal plasma.

  19. Effects of microbial processes on gas generation under expected WIPP repository conditions: Annual report through 1992

    SciTech Connect

    Francis, A.J.; Gillow, J.B.

    1993-09-01

    Microbial processes involved in gas generation from degradation of the organic constituents of transuranic waste under conditions expected at the Waste Isolation Pilot Plant (WIPP) repository are being investigated at Brookhaven National Laboratory. These laboratory studies are part of the Sandia National Laboratories -- WIPP Gas Generation Program. Gas generation due to microbial degradation of representative cellulosic waste was investigated in short-term (< 6 months) and long-term (> 6 months) experiments by incubating representative paper (filter paper, paper towels, and tissue) in WIPP brine under initially aerobic (air) and anaerobic (nitrogen) conditions. Samples from the WIPP surficial environment and underground workings harbor gas-producing halophilic microorganisms, the activities of which were studied in short-term experiments. The microorganisms metabolized a variety of organic compounds including cellulose under aerobic, anaerobic, and denitrifying conditions. In long-term experiments, the effects of added nutrients (trace amounts of ammonium nitrate, phosphate, and yeast extract), no nutrients, and nutrients plus excess nitrate on gas production from cellulose degradation.

  20. The study of gas species on THz generation from laser-induced air plasma

    NASA Astrophysics Data System (ADS)

    Zhao, Ji; Zhang, LiangLiang; Wu, YiJian; Wu, Tong; Yuan, Hui; Zhang, CunLin; Zhao, YueJin

    2015-08-01

    Intense Terahertz waves generated from air-induced plasma and serving as broadband THz source provide a promising broadband source for innovative technology. Terahertz generation in selected gases has attracted more and more researchers' interests in recent years. In this research, the THz emission from different atoms is described, such as nitrogen, argon and helium in Michelson. The THz radiation is detected by a Golay Cell equipped with a 6-mm-diameter diamond-inputting window. It can be seen in the first time that when the pump power lies at a stable level, the THz generation created by the femtosecond laser focusing on the nitrogen is higher than which focusing on the helium, and lower than that produced in the argon gas environment. We believe that the THz intensity is Ar > N > Ne because of its atomic mass, which is Ar > N > Ne as well. It is clear that the Gas molecular decides the release of free electrons ionized from ultra short femtosecond laser through the electronic dynamic analysis. The higher the gas mass is, the stronger the terahertz emission will be. We further explore the THz emission at the different laser power levels, and the experimental results can be commendably quadratic fitted. It can be inferred that THz emission under different gas medium environment still complies with the law of four-wave mixing (FWM) process and has nothing to do with the gas environment: the radiation energy is proportional to the quadratic of incident laser power.

  1. Technology on In-Situ Gas Generation to Recover Residual Oil Reserves

    SciTech Connect

    Sayavur Bakhtiyarov

    2008-02-29

    This final technical report covers the period October 1, 1995 to February 29, 2008. This chapter begins with an overview of the history of Enhanced Oil Recovery techniques and specifically, CO2 flood. Subsequent chapters conform to the manner consistent with the Activities, Tasks, and Sub-tasks of the project as originally provided in Exhibit C1 in the Project Management Plan dated September 20, 1995. These chapters summarize the objectives, status and conclusions of the major project activities performed during the project period. The report concludes by describing technology transfer activities stemming from the project and providing a reference list of all publications of original research work generated by the project team or by others regarding this project. The overall objective of this project was a final research and development in the United States a technology that was developed at the Institute for Geology and Development of Fossil Fuels in Moscow, Russia. Before the technology can be convincingly adopted by United States oil and gas producers, the laboratory research was conducted at Mew Mexico Institute of Mining and Technology. The experimental studies were conducted to measure the volume and the pressure of the CO{sub 2} gas generated according to the new Russian technology. Two experimental devices were designed, built and used at New Mexico Tech facilities for these purposes. The designed setup allowed initiating and controlling the reaction between the 'gas-yielding' (GY) and 'gas-forming' (GF) agents proposed by Russian technology. The temperature was controlled, and the generated gas pressure and volume were recorded during the reaction process. Additionally, the effect of surfactant addition on the effectiveness of the process was studied. An alternative GY reactant was tested in order to increase the efficiency of the CO2 gas generation process. The slim tube and the core flood experimental studies were conducted to define the sweep efficiency

  2. 77 FR 441 - Measurement and Control of Combustible Gas Generation and Dispersal

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-05

    ...The U.S. Nuclear Regulatory Commission (NRC or the Commission) has received a petition for rulemaking (PRM), dated October 14, 2011, from the Natural Resources Defense Council, Inc. (NRDC or the petitioner). The petitioner requests that the NRC amend its regulations regarding the measurement and control of combustible gas generation and dispersal within a power reactor system. The NRC is not......

  3. LOW NOX COMBUSTION CONCEPTS FOR ADVANCED POWER GENERATION SYSTEMS FIRING LOW-BTU GAS

    EPA Science Inventory

    The report gives results of an analysis of several advanced power generating concepts firing low-Btu gasified coal. A combined gas-turbine/steam-cycle power plant with integrated gasifier was the most promising from fuel utilization and economic viewpoints. Two representative com...

  4. Implications of Lower Natural Gas Prices for Electric Generators in the Southeast, The

    EIA Publications

    2009-01-01

    This supplement to the Energy Information Administration's (EIA) May 2009 Short-Term Energy Outlook (STEO) focuses on changes in the utilization of coal- and natural-gas-fired generation capacity in the electric utility sector as the differential between delivered fuel prices narrows.

  5. Saturn V F-1 Engine Gas Generator Blazes Back To Life

    NASA Video Gallery

    On Jan. 10, 2013, a resurrected gas generator from a Saturn V F-1 engine completed two hot-fire tests that are part of a series of tests at Test Stand 116 located in the East Test Area at NASA's Ma...

  6. FLUE GAS DESULFURIZATION SYSTEM CAPABILITIES FOR COAL-FIRED STEAM GENERATORS. VOLUME II. TECHNICAL REPORT

    EPA Science Inventory

    The report discusses the availability of technology for reducing SO2 emissions from coal-fired steam generators using flue gas desulfurization (FGD) systems. Foreign and domestic lime, limestone, double alkali, magnesium slurry, and Wellman-Lord FGD systems are described, and the...

  7. FLUE GAS DESULFURIZATION SYSTEM CAPABILITIES FOR COAL-FIRED STEAM GENERATORS. VOLUME I. EXECUTIVE SUMMARY

    EPA Science Inventory

    The report discusses the availability of technology for reducing SO2 emissions from coal-fired steam generators using flue gas desulfurization (FGD) systems. Foreign and domestic lime, limestone, double alkali, magnesium slurry, and Wellman-Lord FGD systems are described, and the...

  8. Generation and Control of Electrolyte Cathode Atmospheric Glow Discharges using Miniature Gas Flow

    NASA Astrophysics Data System (ADS)

    Shirai, Naoki; Nakazawa, Masato; Ibuka, Shinji; Ishii, Shozo

    Stable electrolyte cathode atmospheric dc glow microdischarges were generated by using a miniature helium gas flow from a nozzle electrode in air. We developed two schemes to control the temporal evolution of the discharge and the interaction between the discharge column and the ambient air. The vaporization of electrolyte solutions takes place and affects the discharge characteristics. It takes time from the start of the discharge. Therefore the discharge was controlled by applying pulse modulated dc voltages. If the voltage was dropped down to zero before the vaporization, the gas discharge developed without the ionization of the components of solution. The helium gas discharge without air developed when the nozzle electrode was placed in a glass capillary. This was confirmed by examining the change in pH of the solution, which usually decreased owing to the generation of nitrogen oxides in the discharge in air.

  9. Generating hydrogen gas from methane with carbon captured as pure spheroidal nanomaterials.

    PubMed

    Cornejo, Andrew; Zhang, Weike; Gao, Lizhen; Varsani, Rahi R; Saunders, Martin; Iyer, K Swaminathan; Raston, Colin L; Chua, Hui Tong

    2011-08-01

    Energy production by using hydrogen gas as a feedstock is considered to be one of the keys to creating clean energy, with the proviso that the gas is generated in a sustainable way with no emissions. A simple, self-sustaining process generating hydrogen gas from methane using inexpensive stainless steel wire-mesh catalysts at elevated temperatures (800 °C) is reported. A theoretical analysis of the production of electricity by this process revealed peak chain energy efficiencies up to 21% (emission free) when using a percentage of the produced hydrogen (approximately 40% of purified yield) as the heat source. In addition, a practical method has been developed to purify the carbon byproduct, affording essentially pure highly graphitic spheroidal carbon for advanced materials applications. PMID:21732440

  10. Advanced gas turbines: The choice for low-cost, environmentally superior electric power generation

    SciTech Connect

    Zeh, C.M.

    1996-08-01

    In July 1993, the US Department of Energy (DOE) initiated an ambitious 8-year program to advance state-of-the-art gas turbine technology for land-based electric power generation. The program, known as the Advanced Turbine System (ATS) Program, is a joint government/industry program with the objective to demonstrate advanced industrial and utility gas turbine systems by the year 2000. The goals of the ATS Program are to develop gas turbine systems capable of providing low-cost electric power, while maintaining environmental superiority over competing power generation options. A progress report on the ATS Program pertaining to program status at DOE will be presented and reviewed in this paper. The technical challenges, advanced critical technology requirements, and systems designs meeting the goals of the program will be described and discussed.

  11. Solid Phase Microextraction On-Fiber Derivatization Using a Stable, Portable, and Reusable Pentafluorophenyl Hydrazine Standard Gas Generating Vial.

    PubMed

    Poole, Justen J; Grandy, Jonathan J; Gómez-Ríos, German A; Gionfriddo, Emanuela; Pawliszyn, Janusz

    2016-07-01

    Solid phase microextraction (SPME) on-fiber derivatization methods have facilitated the achievement of lower detection limits and targeted analysis of various substances that exhibit poor chromatographic behavior, thermal instability, or high reactivity while limiting the use of organic solvents. However, previously developed on-fiber derivatization methods have been hindered by poor loading reproducibility and standard lifetime due to derivatization reagent reactivity. In addition, this reactivity often results in these reagents demonstrating toxic effects, complicating handling and standard formulation. To address this, a reusable standard gas generating vial containing pentafluorophenyl hydrazine (PFPH) has been developed. With this development, SPME fibers can now be reproducibly loaded with derivatization reagent, from an easy to use and safe platform. Validation of the vial using C4-C9 linear aldehyde standards as target analytes demonstrated intrabatch vial reproducibility (2% relative standard deviation (RSD), n = 4), along with PFPH headspace stability over a period of 11 weeks, facilitating reduced reagent consumption due to standard longevity. In addition, reproducibility of the derivatization reaction was observed over 1 week (RSD < 9%), and the linear concentration range was evaluated using headspace extractions from aqueous aldehyde solutions (R(2) > 0.996, 10-200 ppb v/v). Finally, the PFPH-generating vial was applied to the monitoring of volatile aldehydes generated during meat spoilage, as well as an on-site application where the free and total concentration of formaldehyde was determined in car exhaust using a portable GC/MS. To the best of our knowledge, the standard gas generating vial proposed in this work is the first documented device for the long-term storage of reusable headspace standards for a reactive, toxic, and otherwise unstable derivatization reagent standard. PMID:27292013

  12. Generation of electron beams from a laser wakefield acceleration in pure neon gas

    SciTech Connect

    Li, Song; Hafz, Nasr A. M. Mirzaie, Mohammad; Elsied, Ahmed M. M.; Ge, Xulei; Liu, Feng; Sokollik, Thomas; Chen, Min; Sheng, Zhengming; Zhang, Jie; Tao, Mengze; Chen, Liming

    2014-08-15

    We report on the generation of quasimonoenergetic electron beams by the laser wakefield acceleration of 17–50 TW, 30 fs laser pulses in pure neon gas jet. The generated beams have energies in the range 40–120 MeV and up to ∼430 pC of charge. At a relatively high density, we observed multiple electron beamlets which has been interpreted by simulations to be the result of breakup of the laser pulse into multiple filaments in the plasma. Each filament drives its own wakefield and generates its own electron beamlet.

  13. Structured grid generation using a CAD solid model for an aero-gas turbine combustion system

    SciTech Connect

    Eccles, N.C.; Manners, A.P.

    1996-12-31

    An aero-gas turbine combustion system was used to demonstrate the problems of creating a single block structured grid suitable for CFD predictions from a designer`s parametric solid model. The solid model had to be filtered of sub-grid detail and computational fluid volumes generated from the solid model of the metal. Alternative methods of transferring the geometry from the CAD package to the grid generator were considered. The type and method of grid generation was found to influence all stages in manipulating the geometry.

  14. Generation and Migration of Natural Gas in Miocene Strata, Offshore Southeastern Korea

    NASA Astrophysics Data System (ADS)

    Son, Byeong-Kook

    2016-04-01

    Natural gas and condensate are produced from Miocene strata of the Tertiary marine basin, called Ulleung Basin, which is located offshore southeastern Korea. Petroleum system in the basin has not been fully understood, because effective source rocks have not been identified in the area. However, 1-D petroleum system modelling and isotope data indicate that the source rock of the natural gas and condensate might be present at deeper strata than 5,000 m in the basin. In addition, the analysis of diamondoids in the condensate shows that the gas was transformed from type II kerogen. Based on this source rock information and other geological data, 2-D petroleum system modelling was conducted on two cross sections in the southwestern margin of the basin. The 2-D models show two phase generation and migration, which are caused by the geometry of source bed and the maturity level of each pod of the bed. In addition, the accumulation of hydrocarbon is constrained greatly by the timing of development of the regional seal. The first generation and migration of oil and gas begins with a high rate of sedimentation at a deeply and early buried pod of the source bed at 15 Ma. The hydrocarbon, however, migrates upward and diffuses toward the surface. The second generation and migration occurs at around 11 Ma from the other pod of the source bed. This hydrocarbon migrates updip toward anticlines and accumulates into the traps of anticlines. On the other hand, the model shows that the generation and migration is dominated by gas, rather than oil. This model indicates that the accumulation of hydrocarbon can be completed only by the proper and sophisticated combination of the geological elements and the timing of hydrocarbon migration in time and space. This 2-D feature of generation and migration is supported by additional 1-D models of two pseudo-wells drilled on the 2-D section.

  15. Gas-generating polymeric microspheres for long-term and continuous in vivo ultrasound imaging.

    PubMed

    Min, Hyun Su; Kang, Eunah; Koo, Heebeom; Lee, Jaeyoung; Kim, Kwangmeyung; Park, Rang-Woon; Kim, In-San; Choi, Youngseok; Kwon, Ick Chan; Han, Moonhee

    2012-01-01

    Ultrasound (US) imaging is one of the most common biomedical imaging methods, due to the easy assessment and noninvasive way. For more precise and accurate US imaging, many contrast agents have been developed in a form of microbubbles composed of inner gas and shell materials. However, microbubbles showed undesirable short half-life under acoustic field during US imaging and insufficient in vivo stability in blood flow due to diffusion or bubble destruction. Therefore, the improvement of the half-life and stability of microbubbles under in vivo condition is highly needed for long-term in vivo US imaging. Herein, we developed rationally designed gas-generating polymeric microsphere (GGPM) that can produce microbubbles without encapsulation of gas for long-term and continuous US imaging. The poly(cholesteryl γ-butyrolactone-b-propylene oxide), poly(CB-PO), with carbonate side chains was synthesized as gas-generating polymer by ring-opening polymerization of cholestryl γ-butyrolactone (CB) and propylene oxide (PO). As optimal structure for intense US signal generation, porous GGPMs (p-GGPMs) with the average size about 3-5 μm were prepared with poly(CB-PO) by double emulsion method. These p-GGPMs generated continuous US signals over 70 min, while the signals from Sonovue(®), a commercial US contrast agent were completely attenuated within 15 min. This long-term signal duration of p-GGPM was also reproduced when they were subcutaneously injected under the skin of mouse. Moreover, as advanced in vivo application, the fine US imaging of heart in rat was enabled by intravenous injection of p-GGPM. Therefore, these overall results showed the great potential of p-GGPM as gas-generating US contrast agent for in vivo biomedical imaging and diagnosis. PMID:22050793

  16. Inaugural address

    NASA Astrophysics Data System (ADS)

    Joshi, P. S.

    2014-03-01

    From jets to cosmos to cosmic censorship P S Joshi Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India E-mail: psj@tifr.res.in 1. Introduction At the outset, I should like to acknowledge that part of the title above, which tries to capture the main flavour of this meeting, and has been borrowed from one of the plenary talks at the conference. When we set out to make the programme for the conference, we thought of beginning with observations on the Universe, but then we certainly wanted to go further and address deeper questions, which were at the very foundations of our inquiry, and understanding on the nature and structure of the Universe. I believe, we succeeded to a good extent, and it is all here for you in the form of these Conference Proceedings, which have been aptly titled as 'Vishwa Mimansa', which could be possibly translated as 'Analysis of the Universe'! It is my great pleasure and privilege to welcome you all to the ICGC-2011 meeting at Goa. The International Conference on Gravitation and Cosmology (ICGC) series of meetings are being organized by the Indian Association for General Relativity and Gravitation (IAGRG), and the first such meeting was planned and conducted in Goa in 1987, with subsequent meetings taking place at a duration of about four years at various locations in India. So, it was thought appropriate to return to Goa to celebrate the 25 years of the ICGC meetings. The recollections from that first meeting have been recorded elsewhere here in these Proceedings. The research and teaching on gravitation and cosmology was initiated quite early in India, by V V Narlikar at the Banares Hindu University, and by N R Sen in Kolkata in the 1930s. In course of time, this activity grew and gained momentum, and in early 1969, at the felicitation held for the 60 years of V V Narlikar at a conference in Ahmedabad, P C Vaidya proposed the formation of the IAGRG society, with V V Narlikar being the first President. This

  17. Generation and expulsion of petroleum and gas from Almond Formation Coal, Greater Green River Basin, Wyoming

    SciTech Connect

    Garcia-Gonzalez, M.; Surdam, R.C.; Lee, M.L.

    1997-01-01

    Petrographic and geochemical studies of coal from the Almond Formation in the Greater Green River basin demonstrate that the coal contains important volumes of stored liquid petroleum, as well as methane. Modeling indicates that at the basin center, most of the oil generated in the coal has been thermally cracked to gas, whereas at the basin flank the oil-to-gas reaction has barely proceeded. Several new concepts are presented about the mechanism of petroleum generation in coal based on (1) natural maturation trends gleaned form examination of Almond coal samples from different burial depths and (2) similar maturation trends observed in hydrous pyrolysis experiments using immature Almond coal samples. These new concepts show that the oil in the coal was generated during the alteration of desmocollinite and liptinite macerals to exsudatinite (waxy oil) and inertinite solid residue; that the waxy oil was initially stored in porous structures and subsequently in vesicles as the coal matured under increasing temperature; that primary migration of the oil occurred as the generation of a sufficient volume of exsudatinite microfractured the vitrinite-semifusinite vesicles, interconnecting vesicles and pores; and that the thermal cracking of exsudatinite generated a sufficient volume of gas to fracture the vesiculated coal as pore pressure increased and allowed migration of hydrocarbons out of the coal.

  18. Opening addresses.

    PubMed

    Chukudebelu, W O; Lucas, A O; Ransome-kuti, O; Akinla, O; Obayi, G U

    1988-01-01

    The theme of the 3rd International Conference of the Society of Gynecology and Obstetrics of Nigeria (SOGON) held October 26, 1986 in Enugu was maternal morbidity and mortality in Africa. The opening addresses emphasize the high maternal mortality rate in Africa and SOGON's dedication to promoting women's health and welfare. In order to reduce maternal mortality, the scope of this problem must be made evident by gathering accurate mortality rates through maternity care monitoring and auditing. Governments, health professionals, educators, behavioral scientists, and communication specialists have a responsibility to improve maternal health services in this country. By making the population aware of this problem through education, measures can be taken to reduce the presently high maternal mortality rates. Nigerian women are physically unprepared for childbirth; therefore, balanced diets and disease prevention should be promoted. Since about 40% of deliveries are unmanaged, training for traditional birth attendants should be provided. Furthermore, family planning programs should discourage teenage pregnancies, encourage birth spacing and small families, and promote the use of family planning techniques among men. The problem of child bearing and rearing accompanied by hard work should also be investigated. For practices to change so that maternal mortality rates can be reduced, attitudes must be changed such that the current rates are viewed as unacceptable. PMID:12179275

  19. Transition metal catalysis in the generation of petroleum and natural gas. Progress report, [1992--1993

    SciTech Connect

    Mango, F.

    1993-08-01

    A new hypothesis is introduced for the generation of petroleum and natural gas. The transition metals, activated under the reducing conditions of diagenesis, are proposed as catalysts in the generation of light hydrocarbons. The objective of this proposal is to test that hypothesis. Transition metals (Ni, V, Ti, Co, Fe), in kerogen, porphyrins, and as pure compounds, will be tested under catagenic conditions for catalytic activity in the conversion of normal paraffins and hydrogen into light hydrocarbons. If the hypothesis is correct, kerogenous transition metals should become catalytically active under the reducing conditions of diagenesis and catalyze the conversion of paraffins into the light hydrocarbons seen in petroleum. Moreover, the C{sub 1}-C{sub 4} hydrocarbons generated catalytically should be similar in molecular and isotopic compositions to natural gas.

  20. Second-Generation Pressurized Fluidized Bed Combustion: Small gas turbine industrial plant study

    SciTech Connect

    Shenker, J.; Garland, R.; Horazak, D.; Seifert, F.; Wenglarz, R.

    1992-07-01

    Second-Generation Pressurized Fluidized Bed Combustion (PFBC) plants provide a coal-fired, high-efficiency, combined-cycle system for the generation of electricity and steam. The plants use lime-based sorbents in PFB combustors to meet environmental air standards without back-end gas desulfurization equipment. The second-generation system is an improvement over earlier PFBC concepts because it can achieve gas temperatures of 2100{degrees}F and higher for improved cycle efficiency while maintaining the fluidized beds at 1600{degrees}F for enhanced sulfur capture and minimum alkali release. Second-generation PFBC systems are capable of supplying the electric and steam process needs of industrial plants. The basic second-generation system can be applied in different ways to meet a variety of process steam and electrical requirements. To evaluate the potential of these systems in the industrial market, conceptual designs have been developed for six second-generation PFBC plants. These plants cover a range of electrical outputs from 6.3 to 41.5 MWe and steam flows from 46,067 to 442,337 lb/h. Capital and operating costs have been estimated for these six plants and for equivalent (in size) conventional, coal-fired atmospheric fluidized bed combustion cogeneration plants. Economic analyses were conducted to compare the cost of steam for both the second-generation plants and the conventional plants.

  1. Second-Generation Pressurized Fluidized Bed Combustion: Small gas turbine induustrial plant study

    SciTech Connect

    Shenker, J.; Garland, R.; Horazak, D.; Seifert, F.; Wenglarz, R.

    1992-07-01

    Second-Generation Pressurized Fluidized Bed Combustion (PFBC) plants provide a coal-fired, high-efficiency, combined-cycle system for the generation of electricity and steam. The plants use lime-based sorbents in PFB combustors to meet environmental air standards without back-end gas desulfurization equipment. The second-generation system is an improvement over earlier PFBC concepts because it can achieve gas temperatures of 2100[degrees]F and higher for improved cycle efficiency while maintaining the fluidized beds at 1600[degrees]F for enhanced sulfur capture and minimum alkali release. Second-generation PFBC systems are capable of supplying the electric and steam process needs of industrial plants. The basic second-generation system can be applied in different ways to meet a variety of process steam and electrical requirements. To evaluate the potential of these systems in the industrial market, conceptual designs have been developed for six second-generation PFBC plants. These plants cover a range of electrical outputs from 6.3 to 41.5 MWe and steam flows from 46,067 to 442,337 lb/h. Capital and operating costs have been estimated for these six plants and for equivalent (in size) conventional, coal-fired atmospheric fluidized bed combustion cogeneration plants. Economic analyses were conducted to compare the cost of steam for both the second-generation plants and the conventional plants.

  2. Opening Address

    NASA Astrophysics Data System (ADS)

    Yamada, T.

    2014-12-01

    Ladies and Gentlemen, it is my great honor and pleasure to present an opening address of the 3rd International Workshop on "State of the Art in Nuclear Cluster Physics"(SOTANCP3). On the behalf of the organizing committee, I certainly welcome all your visits to KGU Kannai Media Center belonging to Kanto Gakuin University, and stay in Yokohama. In particular, to whom come from abroad more than 17 countries, I would appreciate your participations after long long trips from your homeland to Yokohama. The first international workshop on "State of the Art in Nuclear Cluster Physics", called SOTANCP, was held in Strasbourg, France, in 2008, and the second one was held in Brussels, Belgium, in 2010. Then the third workshop is now held in Yokohama. In this period, we had the traditional 10th cluster conference in Debrecen, Hungary, in 2012. Thus we have the traditional cluster conference and SOTANCP, one after another, every two years. This obviously shows our field of nuclear cluster physics is very active and flourishing. It is for the first time in about 10 years to hold the international workshop on nuclear cluster physics in Japan, because the last cluster conference held in Japan was in Nara in 2003, about 10 years ago. The president in Nara conference was Prof. K. Ikeda, and the chairpersons were Prof. H. Horiuchi and Prof. I. Tanihata. I think, quite a lot of persons in this room had participated at the Nara conference. Since then, about ten years passed. So, this workshop has profound significance for our Japanese colleagues. The subjects of this workshop are to discuss "the state of the art in nuclear cluster physics" and also discuss the prospect of this field. In a couple of years, we saw significant progresses of this field both in theory and in experiment, which have brought better and new understandings on the clustering aspects in stable and unstable nuclei. I think, the concept of clustering has been more important than ever. This is true also in the

  3. Presidential address.

    PubMed

    Vohra, U

    1993-07-01

    The Secretary of India's Ministry of Health and Family Welfare serves as Chair of the Executive Council of the International Institute for Population Sciences in Bombay. She addressed its 35th convocation in 1993. Global population stands at 5.43 billion and increases by about 90 million people each year. 84 million of these new people are born in developing countries. India contributes 17 million new people annually. The annual population growth rate in India is about 2%. Its population size will probably surpass 1 billion by the 2000. High population growth rates are a leading obstacle to socioeconomic development in developing countries. Governments of many developing countries recognize this problem and have expanded their family planning programs to stabilize population growth. Asian countries that have done so and have completed the fertility transition include China, Japan, Singapore, South Korea, and Thailand. Burma, Malaysia, North Korea, Sri Lanka, and Vietnam have not yet completed the transition. Afghanistan, Bangladesh, Iran, Nepal, and Pakistan are half-way through the transition. High population growth rates put pressure on land by fragmenting finite land resources, increasing the number of landless laborers and unemployment, and by causing considerable rural-urban migration. All these factors bring about social stress and burden civic services. India has reduced its total fertility rate from 5.2 to 3.9 between 1971 and 1991. Some Indian states have already achieved replacement fertility. Considerable disparity in socioeconomic development exists among states and districts. For example, the states of Bihar, Madhya Pradesh, Rajasthan, and Uttar Pradesh have female literacy rates lower than 27%, while that for Kerala is 87%. Overall, infant mortality has fallen from 110 to 80 between 1981 and 1990. In Uttar Pradesh, it has fallen from 150 to 98, while it is at 17 in Kerala. India needs innovative approaches to increase contraceptive prevalence rates

  4. Development and commercialization of hot gas filters for power generation applications

    SciTech Connect

    Lippert, T.E.; Bruck, G.J.; Alvin, M.A.; Bachovchin, D.M.; Newby, R.A.

    1995-12-31

    Westinghouse is conducting a broad development program under US Department of Energy (DOE) and corporate program initiatives to commercialize hot gas filtration (HGF) for power generation. Coal and biomass gasification combined cycles (GCC), and Pressurized Fluidized Bed Combustion (PFBC) are advanced power generation cycles that will use HGF to achieve maximum performance. Westinghouse, in conjunction with DOE are participating in several pilot and demonstration test programs in which hot gas filter systems are integrated and operated in coal derived gas streams. This paper reports on HGF testing conducted over the past year in the following pilot plant facilities: At the PFBC Hot Gas Clean Slipstream facility installed at the Tidd 70-MWe bubbling-PFBC Clean Coal Demonstration Plant; at the Ahlstrom 10 Mwt Circulating-PFBC facility located in Karhula, Finland; at the Advanced-PFBC subpilot facility located at the Foster Wheeler Development Corporation Livingston, NJ site; at the Biomass subpilot gasification facility located at the Institute of Gas Technology (IGT). Test results include operating experience on both conventional and advanced candle filter elements.

  5. A Physical Method for Generating the Surface Temperature from Passive Microwave Observations by Addressing the Thermal Sampling Depth for Barren Land

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Zhou, J.; Dai, F.

    2015-12-01

    The land surface temperature (LST) is an important parameter in studying the global and regional climate change. Passive microwave (PMW) remote sensing is less influenced by the atmosphere and has a unique advantage in cloudy regions compared to satellite thermal infrared (TIR) remote sensing. However, the accuracy of LST estimation of many PMW remote sensing models, especially in barren land, is unsatisfactory due to the neglected discrepancy of thermal sampling depth between PMW and TIR. Here, a physical method for PMW remote sensing is proposed to generate the surface temperature, which has the same physically meaning as the TIR surface temperature, by addressing the thermal sampling depth over barren land surface. The method was applied to the Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) data. Validation with the synchronous Moderate Resolution Imaging Spectroradiometer (MODIS) LSTs demonstrates that the method has better performances in estimating LSTs than another two methods that neglect the thermal sampling depth. In Northwest China and a part of Mongolia, the root mean squared errors (RMSEs) the physical method were 3.9 K and 3.7K for daytime and nighttime cases, respectively. In the region of western Namibia, the corresponding RMSEs were 3.8 K and 4.5 K. Further comparison with the in-situ measured LST temperatures at a ground station confirmed the better performance of the proposed method, compared with another two methods. The proposed method will be beneficial for improving the accuracies of the LSTs estimated from PMW observations and integrating the LST products generated from both the TIR and PMW remote sensing.

  6. Gas Generation and Release in Near-Surface Repository at Armenian NPP - 13372

    SciTech Connect

    Grigoryan, G.; Amirjanyan, A.; Hovhannisyan, A.; Gondakyan, Y.

    2013-07-01

    The potential nuclear waste repository at Armenian Nuclear Power Plant (ANPP) can store Low and Intermediate Level Radioactive waste (LL/ILW). In this kind of near-surface repository for radioactive waste, significant quantities of gases may be generated as a result of microbial degradation and corrosion. A discussion is presented of the microbial and chemical degradation of cellulose. For the release of gas, it is assumed that the complete conversion of cellulosic wastes to gases by the action of microbes, is, in principle, permitted. Released radioactive gases such as {sup 14}CO{sub 2} and {sup 14}CH{sub 4} could have a direct pathway to the atmosphere. The potential impact of gas generation, accumulation and migration on the long-term of repository, should therefore be assessed properly. We present here safety assessment result of gas producing radioactive waste disposal by the inhalation dose to a maximally exposed individual above ground, based on some conservative assumptions about release from waste as well as gas generation calculations. (authors)

  7. Storm fronts over galaxy discs: models of how waves generate extraplanar gas and its anomalous kinematics

    NASA Astrophysics Data System (ADS)

    Struck, Curtis; Smith, Daniel C.

    2009-09-01

    The existence of partially ionized, diffuse gas and dust clouds at kiloparsec scale distances above the central planes of edge-on, galaxy discs was an unexpected discovery about 20 years ago. Subsequent observations showed that this extended or extraplanar diffuse interstellar gas (EDIG) has rotation velocities approximately 10-20 per cent lower than those in the central plane, and has been hard to account for. Here, we present results of hydrodynamic models, with radiative cooling and heating from star formation. We find that in models with star formation generated stochastically across the disc, an extraplanar gas layer is generated as long as the star formation is sufficiently strong. However, this gas rotates at nearly the same speed as the midplane gas. We then studied a range of models with imposed spiral or bar waves in the disc. EDIG layers were also generated in these models, but primarily over the wave regions, not over the entire disc. Because of this partial coverage, the EDIG clouds move radially, as well as vertically, with the result that observed kinematic anomalies are reproduced. The implication is that the kinematic anomalies are the result of three-dimensional motions when the cylindrical symmetry of the disc is broken. Thus, the kinematic anomalies are the result of bars or strong waves, and more face-on galaxies with such waves should have an asymmetric EDIG component. The models also indicate that the EDIG can contain a significant fraction of cool gas, and that some star formation can be triggered at considerable heights above the disc mid-plane. We expect all of these effects to be more prominent in young, forming discs, to play a role in rapidly smoothing disc asymmetries and in working to self-regulate disc structure.

  8. Moisture effects on greenhouse gases generation in nitrifying gas-phase compost biofilters.

    PubMed

    Maia, Guilherme D N; Day, George B; Gates, Richard S; Taraba, Joseph L; Coyne, Mark S

    2012-06-01

    Gas-phase compost biofilters are extensively used in concentrated animal feeding operations to remove odors and, in some cases, ammonia from air sources. The expected biochemical pathway for these predominantly aerobic systems is nitrification. However, non-uniform media with low oxygen levels can shift biofilter microbial pathways to denitrification, a source of greenhouse gases. Several factors contribute to the formation of anoxic/anaerobic zones: media aging, media and particle structure, air velocity distribution, compaction, biofilm thickness, and moisture content (MC) distribution. The present work studies the effects of media moisture conditions on ammonia (NH(3)) removal and greenhouse gas generation (nitrous oxide, N(2)O and methane, CH(4)) for gas-phase compost biofilters subject to a 100-day controlled drying process. Continuous recordings were made for the three gases and water vapor (2.21-h sampling cycle, each cycle consisted of three gas species, and water vapor, for a total of 10,050 data points). Media moisture conditions were classified into three corresponding media drying rate (DR) stages: Constant DR (wetter media), falling DR, and stable-dry system. The first-half of the constant DR period (0-750 h; MC=65-52%, w.b.) facilitated high NH(3) removal rates, but higher N(2)O generation and no CH(4) generation. At the drier stages of the constant DR (750-950 h; MC=52-48%, w.b.) NH(3) removal remained high but N(2)O net generation decreased to near zero. In the falling DR stage (1200-1480 h; MC=44-13%) N(2)O generation decreased, CH(4) increased, and NH(3) was no longer removed. No ammonia removal or greenhouse gas generation was observed in the stable-dry system (1500-2500 h; MC=13%). These results indicate that media should remain toward the drier region of the constant DR (in close proximity to the falling DR stage; MC=50%, approx.), to maintain high levels of NH(3) removal, reduced levels of N(2)O generation, and nullify levels of CH(4

  9. The selection of convertible engines with current gas generator technology for high speed rotorcraft

    NASA Technical Reports Server (NTRS)

    Eisenberg, Joseph D.

    1990-01-01

    NASA-Lewis has sponsored two studies to determine the most promising convertible engine concepts for high speed rotorcraft. These studies projected year 2000 convertible technology limited to present gas generator technology. Propulsion systems for utilization on aircraft needing thrust only during cruise and those aircraft needing both power and thrust at cruise were investigated. Mission calculations for the two contractors involved were based upon the fold tilt rotor concept. Analysis and comparison of the General Electric concepts (geared UDF, clutched fan, and VIGV fan), and the Allison Gas Turbine concepts (clutched fan, VIGV fan, variable pitch fan, single rotation tractor propfan, and counter rotation tractor propfan) are presented.

  10. Efficient generation in a chemical oxygen - iodine laser with a low buffer-gas flow rate

    SciTech Connect

    Azyazov, V N; Safonov, V S; Ufimtsev, N I

    2002-09-30

    The efficient generation in a chemical oxygen - iodine laser (COIL) with a low buffer-gas flow rate for Mach numbers M {<=} 1 is demonstrated. The maximum output power of the COIL was 415 W for a molecular chlorine flow rate of 20 mmol s{sup -1}, which corresponds to a chemical efficiency {eta}{sub ch} =23%. It is shown that the substitution of the buffer gas CO{sub 2} for N{sub 2} does not cause any significant variation in the dependence of the output power on the degree of dilution of the active medium. (lasers)

  11. The selection of convertible engines with current gas generator technology for high speed rotorcraft

    NASA Technical Reports Server (NTRS)

    Eisenberg, Joseph D.

    1990-01-01

    NASA-Lewis sponsored two studies to determine the most promising convertible engine concepts for high speed rotorcraft. These studies projected year 2000 convertible technology limited to present gas generator technology. Propulsion systems for utilization on aircraft needing thrust only during cruise and those aircraft needing both power and thrust at cruise were investigated. Mission calculations for the two contractors involved were based upon the fold tilt rotor concept. Analysis and comparison of the General Electric concepts (geared UDF, clutched fan, and Variable Inlet Guide Vane (VIGV) fan), and the Allison Gas Turbine concepts (clutched fan, VIGV fan, variable pitch fan, single rotation tractor propfan, and counter rotation tractor propfan) are presented.

  12. Radiolytic gas generation from cement-based waste hosts for DOE low-level radioactive wastes

    SciTech Connect

    Dole, L.R.; Friedman, H.A.

    1986-01-01

    Using cement-based immobilization binders with simulated radioactive waste containing sulfate, nitrate, nitrite, phosphate, and fluoride anions, the gamma- and alpha-radiolytic gas generation factors (G/sub t/, molecules/100 eV) and gas compositions were measured on specimens of cured grouts. These tests studied the effects of; (1) waste composition; (2) the sample surface-to-volume ratio; (3) the waste slurry particle size; and (4) the water content of the waste host formula. The radiolysis test vessels were designed to minimize the ''dead'' volume and to simulate the configuration of waste packages.

  13. Welcome Address

    NASA Astrophysics Data System (ADS)

    Kiku, H.

    2014-12-01

    Ladies and Gentlemen, It is an honor for me to present my welcome address in the 3rd International Workshop on "State of the Art in Nuclear Cluster Physics"(SOTANCP3), as the president of Kanto Gakuin University. Particularly to those from abroad more than 17 countries, I am very grateful for your participation after long long trips from your home to Yokohama. On the behalf of the Kanto Gakuin University, we certainly welcome your visit to our university and stay in Yokohama. First I would like to introduce Kanto Gakuin University briefly. Kanto Gakuin University, which is called KGU, traces its roots back to the Yokohama Baptist Seminary founded in 1884 in Yamate, Yokohama. The seminary's founder was Albert Arnold Bennett, alumnus of Brown University, who came to Japan from the United States to establish a theological seminary for cultivating and training Japanese missionaries. Now KGU is a major member of the Kanto Gakuin School Corporation, which is composed of two kindergartens, two primary schools, two junior high schools, two senior high schools as well as KGU. In this university, we have eight faculties with graduate school including Humanities, Economics, Law, Sciences and Engineering, Architecture and Environmental Design, Human and Environmental Studies, Nursing, and Law School. Over eleven thousands students are currently learning in our university. By the way, my major is the geotechnical engineering, and I belong to the faculty of Sciences and Engineering in my university. Prof. T. Yamada, here, is my colleague in the same faculty. I know that the nuclear physics is one of the most active academic fields in the world. In fact, about half of the participants, namely, more than 50 scientists, come from abroad in this conference. Moreover, I know that the nuclear physics is related to not only the other fundamental physics such as the elementary particle physics and astrophysics but also chemistry, medical sciences, medical cares, and radiation metrology

  14. Variance Analysis of Wind and Natural Gas Generation under Different Market Structures: Some Observations

    SciTech Connect

    Bush, B.; Jenkin, T.; Lipowicz, D.; Arent, D. J.; Cooke, R.

    2012-01-01

    Does large scale penetration of renewable generation such as wind and solar power pose economic and operational burdens on the electricity system? A number of studies have pointed to the potential benefits of renewable generation as a hedge against the volatility and potential escalation of fossil fuel prices. Research also suggests that the lack of correlation of renewable energy costs with fossil fuel prices means that adding large amounts of wind or solar generation may also reduce the volatility of system-wide electricity costs. Such variance reduction of system costs may be of significant value to consumers due to risk aversion. The analysis in this report recognizes that the potential value of risk mitigation associated with wind generation and natural gas generation may depend on whether one considers the consumer's perspective or the investor's perspective and whether the market is regulated or deregulated. We analyze the risk and return trade-offs for wind and natural gas generation for deregulated markets based on hourly prices and load over a 10-year period using historical data in the PJM Interconnection (PJM) from 1999 to 2008. Similar analysis is then simulated and evaluated for regulated markets under certain assumptions.

  15. The controlling effect of temperature in the application of permeation tube (PT) devices in standard gas generation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, the performance of permeation tube (PT) devices for the generation of VOC calibration gas was examined by successively generating BTX gas at five temperatures (30, 50, 70, 80, and 100C) and two flow rates (400 and 800 mL/min). A distinct relationship was observed between temperatures ...

  16. Design, Fabrication and Performance of Open Source Generation I and II Compliant Hydrodynamic Gas Foil Bearings

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Radil, Kevin C.; Bruckner, Robert J.; Howard, S. Adam

    2007-01-01

    Foil gas bearings are self-acting hydrodynamic bearings made from sheet metal foils comprised of at least two layers. The innermost top foil layer traps a gas pressure film that supports a load while a layer or layers underneath provide an elastic foundation. Foil bearings are used in many lightly loaded, high-speed turbo-machines such as compressors used for aircraft pressurization, and small micro-turbines. Foil gas bearings provide a means to eliminate the oil system leading to reduced weight and enhanced temperature capability. The general lack of familiarity of the foil bearing design and manufacturing process has hindered their widespread dissemination. This paper reviews the publicly available literature to demonstrate the design, fabrication and performance testing of both first and second generation bump style foil bearings. It is anticipated that this paper may serve as an effective starting point for new development activities employing foil bearing technology.

  17. A space-based combined thermophotovoltaic electric generator and gas laser solar energy conversion system

    NASA Technical Reports Server (NTRS)

    Yesil, Oktay

    1989-01-01

    This paper describes a spaceborne energy conversion system consisting of a thermophotovoltaic electric generator and a gas laser. As a power source for the converson, the system utilizes an intermediate blackbody cavity heated to a temperature of 2000-2400 K by concentrated solar radiation. A double-layer solar cell of GaAs and Si forms a cylindrical surface concentric to this blackbody cavity, receiving the blackbody radiation and converting it into electricity with cell conversion efficiency of 50 percent or more. If the blackbody cavity encloses a laser medium, the blackbody radiation can also be used to simultaneously pump a lasing gas. The feasibility of blackbody optical pumping at 4.3 microns in a CO2-He gas mixture was experimentally demonstrated.

  18. Generation and confinement of microwave gas-plasma in photonic dielectric microstructure.

    PubMed

    Debord, B; Jamier, R; Gérôme, F; Leroy, O; Boisse-Laporte, C; Leprince, P; Alves, L L; Benabid, F

    2013-10-21

    We report on a self-guided microwave surface-wave induced generation of ~60 μm diameter and 6 cm-long column of argon-plasma confined in the core of a hollow-core photonic crystal fiber. At gas pressure of 1 mbar, the micro-confined plasma exhibits a stable transverse profile with a maximum gas-temperature as high as 1300 ± 200 K, and a wall-temperature as low as 500 K, and an electron density level of 10¹⁴ cm⁻³. The fiber guided fluorescence emission presents strong Ar⁺ spectral lines in the visible and near UV. Theory shows that the observed combination of relatively low wall-temperature and high ionisation rate in this strongly confined configuration is due to an unprecedentedly wide electrostatic space-charge field and the subsequent ion acceleration dominance in the plasma-to-gas power transfer. PMID:24150390

  19. GAS-GENERATION EXPERIMENTS FOR LONG-TERM STORAGE OF TRU WASTES AT WIPP

    SciTech Connect

    Felicione, F.S.; Carney, K.P.; Dwight, C.C.; Cummings, D.G.; Foulkrod, L.E.

    2003-02-27

    An experimental investigation was conducted for gas generation in contact-handled transuranic (CH-TRU) wastes subjected for several years to conditions similar to those expected to occur at the Waste Isolation Pilot Plant (WIPP) should the repository eventually become inundated with brine. Various types of actual CH-TRU wastes were placed into 12 corrosion-resistant vessels. The vessels were loosely filled with the wastes, which were submerged in synthetic brine having the same chemical composition as that in the WIPP vicinity. The vessels were also inoculated with microbes found in the Salado Formation at WIPP. The vessels were sealed, purged, and the approximately 750-ml headspace was pressurized with nitrogen gas to approximately 146 atmospheres to create anoxic conditions at the lithostatic pressure expected in the repository were it inundated. The temperature was maintained at the expected 30 C. The test program objective was to measure the quantities and species of gases generate d by metal corrosion, radiolysis, and microbial activity. These data will assist in the specification of the rates at which gases are produced under inundated repository conditions for use in the WIPP Performance Assessment computer models. These experiments were very carefully designed, constructed, instrumented, and performed. Approximately 6-1/2 years of continuous, undisturbed testing were accumulated. Several of the vessels showed significantly elevated levels of generated gases, virtually all of which was hydrogen. One vessel measured over 4.2% hydrogen, by volume. Two other vessels generated well over 1% hydrogen, and another was at nearly 1%. Only small quantities of other gases, principally carbon dioxide, were detected. Gas generation was found to depend strongly on the waste composition. The maximum hydrogen generation occurred in tests containing carbon steel. Average corrosion penetration rates in carbon-steel of up to 2.3 microns per year were deduced. Conversion of

  20. Intense terahertz-pulse generation by four-wave mixing process in induced gas plasma

    NASA Astrophysics Data System (ADS)

    Wicharn, S.; Buranasiri, P.

    2015-08-01

    In this article, we have numerically investigated an intense terahertz (THz) pulses generation in gaseous plasma based on the third-order nonlinear effect, four-wave mixing rectification (FWMR). We have proposed that the fundamental fields and second-harmonic field of ultra-short pulse lasers are combined and focused into a very small gas chamber to induce a gaseous plasma, which intense THz pulse is produced. To understand the THz generation process, the first-order multiple-scale perturbation method (MSPM) has been utilized to derive a set of nonlinear coupled-mode equations for interacting fields such as two fundamental fields, a second-harmonic field, and a THz field. Then, we have simulate the intense THz-pulse generation by using split step-beam propagation method (SS-BPM) and calculated output THz intensities. Finally, the output THz intensities generated from induced air, nitrogen, and argon plasma have been compared.

  1. Generation of hydrogen rich gas through fluidized bed gasification of biomass.

    PubMed

    Karmakar, M K; Datta, A B

    2011-01-01

    The objective of this study was to investigate the process of generating hydrogen rich syngas through thermo chemical fluidized bed gasification of biomass. The experiments were performed in a laboratory scale externally heated biomass gasifier. Rice husk had been taken as a representative biomass and, steam had been used as the fluidizing and gasifying media. A thermodynamic equilibrium model was used to predict the gasification process. The work included the parametric study of process parameters such as reactor temperature and steam biomass ratio which generally influence the percentage of hydrogen content in the product gas. Steam had been used here to generate nitrogen free product gas and also to increase the hydrogen concentration in syngas with a medium range heating value of around 12 MJ/Nm3. PMID:20797847

  2. Gas-generator pressurization system experimental development method of the LV propellant tanks

    NASA Astrophysics Data System (ADS)

    Logvinenko, A.

    2009-01-01

    The approved efficient method of experimental development is given in the example of accumulated experience in the gas-generator pressurization system development of the LV propellant tanks. To the present time, acceptable calculated methods has not been created from complexity of thermo-mass-transfer processes. Therefore, under the development of similar systems the main attention is centered to its ground experimental development which requires special benches, corresponding competent structures, great time and material expenditure. The approved method of gas-generator pressurization system experimental development is proposed. It is based on the energy analysis of influenced factors and selection of its limit-possible operation modes. Practical use is allowed to decrease significantly the test volume, to decrease material expenditure and time for pressurization system experimental development under complex assurance of its optimal main characteristics.

  3. A Gas Embedded Z-pinch Driven by SPEED2 Generator

    SciTech Connect

    Soto, Leopoldo; Moreno, Jose; Sylvester, Gustavo; Silva, Patricio; Zambra, Marcelo; Pavez, Cristian; Clausse, Alejandro

    2006-12-04

    A gas embedded Z-pinch has been implemented using the SPEED2 generator (4.1 {mu}F equivalent Marx generator capacity, 300 kV, 4 MA in short circuit, 187 kJ, 400 ns rise time, dI/dt{approx}1013 A/s). Initial conditions to produce a gas embedded z-pinch with enhanced stability by means resistive effects and by finite Larmor radius effects were obtained and electrodes were constructed in order to obtain a double column Z-pinch and a hollow discharge. Experiments were carried out in deuterium at mega amperes currents. Current derivative and voltage signals have been obtained. In addition interferograms have been obatined using a pulse Nd-YAG laser (8ns FWMH at 532nm). Preliminary results on neutron emission were also obtained.

  4. Accounting for fuel price risk when comparing renewable togas-fired generation: the role of forward natural gas prices

    SciTech Connect

    Bolinger, Mark; Wiser, Ryan; Golove, William

    2004-07-17

    Unlike natural gas-fired generation, renewable generation (e.g., from wind, solar, and geothermal power) is largely immune to fuel price risk. If ratepayers are rational and value long-term price stability, then--contrary to common practice--any comparison of the levelized cost of renewable to gas-fired generation should be based on a hedged gas price input, rather than an uncertain gas price forecast. This paper compares natural gas prices that can be locked in through futures, swaps, and physical supply contracts to contemporaneous long-term forecasts of spot gas prices. We find that from 2000-2003, forward gas prices for terms of 2-10 years have been considerably higher than most contemporaneous long-term gas price forecasts. This difference is striking, and implies that comparisons between renewable and gas-fired generation based on these forecasts over this period have arguably yielded results that are biased in favor of gas-fired generation.

  5. Measurement of molecular rotational temperature in a supersonic gas jet with high-order harmonic generation.

    PubMed

    Yoshii, Kazumichi; Miyaji, Godai; Miyazaki, Kenzo

    2009-06-01

    We apply high-order harmonic generation to sensitive measurements of the molecular rotational temperature in a thin supersonic gas beam. The method uses nonresonant pump and probe femtosecond laser pulses to generate harmonic radiation from coherently rotating molecules. The rotational temperature of molecules can be derived accurately with high spatial and temporal resolutions from the Fourier spectrum of time-dependent signals. The validity of this method was tested for an expanding flow of an N(2) beam with a rapid temperature decrease. The results show the versatile applicability of this method. PMID:19488137

  6. A compact repetitive high-voltage nanosecond pulse generator for the application of gas discharge.

    PubMed

    Pang, Lei; Zhang, Qiaogen; Ren, Baozhong; He, Kun

    2011-04-01

    Uniform and stable discharge plasma requires very short duration pulses with fast rise times. A repetitive high-voltage nanosecond pulse generator for the application of gas discharge is presented in this paper. It is constructed with all solid-state components. Two-stage magnetic compression is used to generate a short duration pulse. Unlike in some reported studies, common commercial fast recovery diodes instead of a semiconductor opening switch (SOS) are used in our experiment that plays the role of SOS. The SOS-like effects of four different kinds of diodes are studied experimentally to optimize the output performance. It is found that the output pulse voltage is higher with a shorter reverse recovery time, and the rise time of pulse becomes faster when the falling time of reverse recovery current is shorter. The SOS-like effect of the diodes can be adjusted by changing the external circuit parameters. Through optimization the pulse generator can provide a pulsed voltage of 40 kV with a 40 ns duration, 10 ns rise time, and pulse repetition frequency of up to 5 kHz. Diffuse plasma can be formed in air at standard atmospheric pressure using the developed pulse generator. With a light weight and small packaging the pulse generator is suitable for gas discharge application. PMID:21529005

  7. A compact repetitive high-voltage nanosecond pulse generator for the application of gas discharge

    NASA Astrophysics Data System (ADS)

    Pang, Lei; Zhang, Qiaogen; Ren, Baozhong; He, Kun

    2011-04-01

    Uniform and stable discharge plasma requires very short duration pulses with fast rise times. A repetitive high-voltage nanosecond pulse generator for the application of gas discharge is presented in this paper. It is constructed with all solid-state components. Two-stage magnetic compression is used to generate a short duration pulse. Unlike in some reported studies, common commercial fast recovery diodes instead of a semiconductor opening switch (SOS) are used in our experiment that plays the role of SOS. The SOS-like effects of four different kinds of diodes are studied experimentally to optimize the output performance. It is found that the output pulse voltage is higher with a shorter reverse recovery time, and the rise time of pulse becomes faster when the falling time of reverse recovery current is shorter. The SOS-like effect of the diodes can be adjusted by changing the external circuit parameters. Through optimization the pulse generator can provide a pulsed voltage of 40 kV with a 40 ns duration, 10 ns rise time, and pulse repetition frequency of up to 5 kHz. Diffuse plasma can be formed in air at standard atmospheric pressure using the developed pulse generator. With a light weight and small packaging the pulse generator is suitable for gas discharge application.

  8. Rapid hydrogen gas generation using reactive thermal decomposition of uranium hydride.

    SciTech Connect

    Kanouff, Michael P.; Van Blarigan, Peter; Robinson, David B.; Shugard, Andrew D.; Gharagozloo, Patricia E.; Buffleben, George M.; James, Scott Carlton; Mills, Bernice E.

    2011-09-01

    Oxygen gas injection has been studied as one method for rapidly generating hydrogen gas from a uranium hydride storage system. Small scale reactors, 2.9 g UH{sub 3}, were used to study the process experimentally. Complimentary numerical simulations were used to better characterize and understand the strongly coupled chemical and thermal transport processes controlling hydrogen gas liberation. The results indicate that UH{sub 3} and O{sub 2} are sufficiently reactive to enable a well designed system to release gram quantities of hydrogen in {approx} 2 seconds over a broad temperature range. The major system-design challenge appears to be heat management. In addition to the oxidation tests, H/D isotope exchange experiments were performed. The rate limiting step in the overall gas-to-particle exchange process was found to be hydrogen diffusion in the {approx}0.5 {mu}m hydride particles. The experiments generated a set of high quality experimental data; from which effective intra-particle diffusion coefficients can be inferred.

  9. Organic richness and gas generation potential of Permian Barren Measures from Raniganj field, West Bengal, India

    NASA Astrophysics Data System (ADS)

    Boruah, Annapurna; Ganapathi, S.

    2015-07-01

    The organic geochemistry of shales in terms of its organic richness, hydrocarbon source potential, thermal maturity, depositional environment, etc., are essential stipulations for shale gas resources assessment. In this study, a total of 32 core samples of Permian Barren Measures from four boreholes in Raniganj field of Damodar Basin were analysed to evaluate their gas generation potential using Rock-Eval pyrolysis techniques. Petrographic analysis brings out the lithofacies of Barren Measures as carbonaceous silty shale, iron rich claystone and sand-shale intercalation. The total organic content (TOC) of the shale units of Barren Measures ranges from 3.75 to 20.9 wt%, whereas hydrogen index (HI) ranges from 58.45 to 125.34 mg HC/g TOC. Present study suggests early to late maturated (0.6-1%) organic matters in Barren Measures with gas prone type III kerogen. The study analysed the effect of burial history on the preservation and maturation of organic matters. The organic richness, kerogen type, thermal maturity and petrographic properties of Barren Measures signify fair to excellent gas generation potential.

  10. A liquid turbine generator as a high-temperature attachment to a gas turbine

    NASA Astrophysics Data System (ADS)

    Shershnev, N. A.; Sinenkov, A. N.; Gorin, A. I.

    1984-11-01

    A vortex chamber working with gaseous combustion products effectively retains injected liquid metal in the form of a rotating annular layer, and this is considered as a possible basic component in a liquid generator constituting a high-temperature attachment to a gas-turbine system. It is shown that copper or nickel should be used as the working metal. Model cold experiments have given efficencies for the chamber working with water and air at a level of 0.4-0.45.

  11. Entropy Generation/Availability Energy Loss Analysis Inside MIT Gas Spring and "Two Space" Test Rigs

    NASA Technical Reports Server (NTRS)

    Ebiana, Asuquo B.; Savadekar, Rupesh T.; Patel, Kaushal V.

    2006-01-01

    The results of the entropy generation and availability energy loss analysis under conditions of oscillating pressure and oscillating helium gas flow in two Massachusetts Institute of Technology (MIT) test rigs piston-cylinder and piston-cylinder-heat exchanger are presented. Two solution domains, the gas spring (single-space) in the piston-cylinder test rig and the gas spring + heat exchanger (two-space) in the piston-cylinder-heat exchanger test rig are of interest. Sage and CFD-ACE+ commercial numerical codes are used to obtain 1-D and 2-D computer models, respectively, of each of the two solution domains and to simulate the oscillating gas flow and heat transfer effects in these domains. Second law analysis is used to characterize the entropy generation and availability energy losses inside the two solution domains. Internal and external entropy generation and availability energy loss results predicted by Sage and CFD-ACE+ are compared. Thermodynamic loss analysis of simple systems such as the MIT test rigs are often useful to understand some important features of complex pattern forming processes in more complex systems like the Stirling engine. This study is aimed at improving numerical codes for the prediction of thermodynamic losses via the development of a loss post-processor. The incorporation of loss post-processors in Stirling engine numerical codes will facilitate Stirling engine performance optimization. Loss analysis using entropy-generation rates due to heat and fluid flow is a relatively new technique for assessing component performance. It offers a deep insight into the flow phenomena, allows a more exact calculation of losses than is possible with traditional means involving the application of loss correlations and provides an effective tool for improving component and overall system performance.

  12. Chemical reaction model for oil and gas generation from type 1 and type 2 kerogen

    SciTech Connect

    Braun, R.L.; Burnham, A.K.

    1993-06-01

    A global model for the generation of oil and gas from petroleum source rocks is presented. The model consists of 13 chemical species and 10 reactions, including an alternate-pathway mechanism for kerogen pyrolysis. Reaction rate parameters and stoichiometry coefficients determined from a variety of pyrolysis data are given for both type I and type II kerogen. Use of the chemical reaction model is illustrated for typical geologic conditions.

  13. Effect of Li 2CO 3 additive on gas generation in lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Shin, Jee-Sun; Han, Chi-Hwan; Jung, Un-Ho; Lee, Shung-Ik; Kim, Hyeong-Jin; Kim, Keon

    To elucidate the mechanism of gas generation during charge-discharge cycling of a lithium-ion cell, the generated gases and passive films on the carbon electrode are examined by means of gas chromatography (GC) and Fourier transform infrared (FTIR) spectroscopy. In ethyl carbonate/dimethyl carbonate and ethyl carbonate/diethyl carbonate 1 M LiPF 6 electrolytes, the detected gaseous products are CO 2, CO, CH 4, C 2H 4, C 2H 6, etc. The FTIR spectrum of the surface of the carbon electrode shows bands which correspond to Li 2CO 3, ROCO 2Li, (ROCO 2Li) 2, and RCO 2Li. These results suggest that gas evolution is caused by electrode decomposition, reactive trace impurities, and electrolyte reduction. The surface of the electrode is composed of electrolyte reduction products. When 0.05 M Li 2CO 3 is added as an electrolyte additive, the total volume of generated gases is reduced, and the discharge capacity and the conductivity of lithium-ions are increased. These results can be explained by a more compact and thin 'solid electrolyte interface' film on the carbon electrode formed by Li 2CO 3, which effectively prevents solvent co-intercalation and carbon exfoliation.

  14. An assessment of radiolytic gas generation: Impacts from Rocky Flats Plant residue elimination alternatives. Final report

    SciTech Connect

    Not Available

    1993-02-26

    This report evaluates the Sandia National Laboratory-Albuquerque analytical model that is used to support present wattage limit decisions for various matrix forms from the Residue Elimination Project for Waste Isolation Pilot Plant waste acceptability. This study includes (1) a comparison of the SNL-A model to Rocky Flats Plant models for consistency of assumptions and the phenomena considered in the models, and (2) an evaluation of the appropriateness of the Sandia National Laboratory-Albuquerque model to Rocky Flats Plant residues, considering that the original intent was to model wastes rather than residues. The study draws the following conclusions: (1) only real-time gas generation testing of specific waste streams may provide a sound basis for an increase in the transportation wattage limit of specific waste streams, and (2) the radiolytic gas generation rate from Residue Elimination Project waste emplaced at Waste Isolation Pilot Plant, under worst-case conditions, is not a significant factor in comparison to the total gas generation rate due to radiolysis, microbial degradation, and corrosion.

  15. A three-dimensional algebraic grid generation scheme for gas turbine combustors with inclined slots

    NASA Technical Reports Server (NTRS)

    Yang, S. L.; Cline, M. C.; Chen, R.; Chang, Y. L.

    1993-01-01

    A 3D algebraic grid generation scheme is presented for generating the grid points inside gas turbine combustors with inclined slots. The scheme is based on the 2D transfinite interpolation method. Since the scheme is a 2D approach, it is very efficient and can easily be extended to gas turbine combustors with either dilution hole or slot configurations. To demonstrate the feasibility and the usefulness of the technique, a numerical study of the quick-quench/lean-combustion (QQ/LC) zones of a staged turbine combustor is given. Preliminary results illustrate some of the major features of the flow and temperature fields in the QQ/LC zones. Formation of co- and counter-rotating bulk flow and shape temperature fields can be observed clearly, and the resulting patterns are consistent with experimental observations typical of the confined slanted jet-in-cross flow. Numerical solutions show the method to be an efficient and reliable tool for generating computational grids for analyzing gas turbine combustors with slanted slots.

  16. Effect of Orifice Diameter on Bubble Generation Process in Melt Gas Injection to Prepare Aluminum Foams

    NASA Astrophysics Data System (ADS)

    Yuan, Jianyu; Li, Yanxiang; Wang, Ningzhen; Cheng, Ying; Chen, Xiang

    2016-06-01

    The bubble generation process in conditioned A356 alloy melt through submerged spiry orifices with a wide diameter range (from 0.07 to 1.0 mm) is investigated in order to prepare aluminum foams with fine pores. The gas flow rate and chamber pressure relationship for each orifice is first determined when blowing gas in atmospheric environment. The effects of chamber pressure ( P c) and orifice diameter ( D o) on bubble size are then analyzed separately when blowing gas in melt. A three-dimensional fitting curve is obtained illustrating both the influences of orifice diameter and chamber pressure on bubble size based on the experimental data. It is found that the bubble size has a V-shaped relationship with orifice diameter and chamber pressure neighboring the optimized parameter ( D o = 0.25 mm, P c = 0.4 MPa). The bubble generation mechanism is proposed based on the Rayleigh-Plesset equation. It is found that the bubbles will not be generated until a threshold pressure difference is reached. The threshold pressure difference is dependent on the orifice diameter, which determines the time span of pre-formation stage and bubble growth stage.

  17. Testing marine shales' ability to generate catalytic gas at low temperature

    NASA Astrophysics Data System (ADS)

    Wei, L.; Schimmelmann, A.; Drobniak, A.; Sauer, P. E.; Mastalerz, M.

    2013-12-01

    Hydrocarbon gases are generally thought to originatevia low-temperature microbial or high-temperature thermogenicpathways (Whiticar, 1996) that can be distinguished by compound-specific hydrogen and carbon stable isotope ratios. An alternative low-temperature catalytic pathway for hydrocarbon generation from sedimentary organic matter has been proposed to be active at temperatures as low as 50oC (e.g.,Mango and Jarvie,2009,2010; Mango et al., 2010; Bartholomew et al., 1999). This hypothesis, however, still requires rigoroustesting by independent laboratory experiments.The possibility of catalytic generation of hydrocarbons in some source rocks (most likely in relatively impermeable and organic-rich shales where reduced catalytic centers can be best preserved) would offer an explanation for the finding of gas of non-microbial origin in formations that lack the thermal maturity for generating thermogenic gas.It is unknown whether catalytically generated methane would be isotopically different from thermogenicmethane (δ13CCH4>-50‰, δ2HCH4from -275‰ to -100‰) ormicrobially generated methane (δ13CCH4from -40‰ to -110‰, δ2HCH4from -400‰to -150‰) (Whiticar, 1998). In order to test for catalytic gas generationin water-wet shales and coals, we are conductinglaboratory experiments at three temperatures (60°C, 100°C, 200°C)and three pressures (ambient pressure, 107 Pa, 3x107 Pa)over periods of six months to several years. So far, our longest running experiments have reached one year. We sealed different types of thermally immature, pre-evacuatedshales (Mowry, New Albany, and Mahoganyshales) and coals (SpringfieldCoal and Wilcoxlignite)with isotopically defined waters in gold cells in the absence of elemental oxygen.Preliminary results show that these samples, depending on conditions, can generate light hydrocarbon gases (methane, ethane and propane) and CO2. Methane, CO2, and traces of H2havebeen generated at 60°C, whereas experiments at 100°C and 200

  18. Off-Gas Generation Rate during Chemical Cleaning Operations at the Savannah River Site - 12499

    SciTech Connect

    Wiersma, Bruce J.; Subramanian, Karthik H.; Ketusky, Edward T.

    2012-07-01

    The enhanced chemical cleaning process (ECC) is being developed at the Savannah River Site (SRS) to remove the residual radioactive sludge heel that remains in a liquid waste storage tank. Oxalic acid is the chemical agent utilized for this purpose. However, the acid also corrodes the carbon steel tank wall and cooling coils. If the oxalic acid has little interaction with the sludge, hydrogen gas could conceivably evolve at cathodic areas due to the corrosion of the carbon steel. Scenarios where hydrogen evolution could occur during ECC include the initial filling of the tank prior to agitation and near the end of the process when there is little or no sludge present. The purpose of this activity was to provide a bounding estimate for the hydrogen generation rate during the ECC process. Sealed vessel coupon tests were performed to estimate the hydrogen generation rate due to corrosion of carbon steel by oxalic acid. These tests determined the maximum instantaneous hydrogen generation rate, the rate at which the generation rate decays, and the total hydrogen generated. The tests were performed with polished ASTM A285 Grade C carbon steel coupons. This steel is representative of the Type I and II waste tanks at SRS. Bounding conditions were determined for the solution environment. The oxalic acid concentration was 2.5 wt.% and the test temperature was 75 deg. C. The test solution was agitated and contained no sludge simulant. Duplicate tests were performed and showed excellent reproducibility for the hydrogen generation rate and total hydrogen generated. The results showed that the hydrogen generation rate was initially high, but decayed rapidly within a couple of days. A statistical model was developed to predict the instantaneous hydrogen generation rate as a function of exposure time by combining both sets of data. An upper bound on the maximum hydrogen generation rate was determined from the upper 95% confidence limit. The upper bound limit on the maximum

  19. Compound-specific carbon isotope analysis of instantaneous gas generated from shaly coal during hydrous pyrolysis

    NASA Astrophysics Data System (ADS)

    Tsai, Wen-Yu; Sun, Chih-Hsien; Huang, Wuu-Liang

    2010-05-01

    Isotopes of natural gases have provided important information for indicating their maturation, origins and influencing factors during the generation processes. In order to distinguish compositions of gas generated at different intervals of maturities, the present study investigates the variation of compound-specific carbon isotope (CSI) ratios of hydrocarbon gases from a shaly coal by instantaneous hydrous pyrolysis, during which the earlier generated gas was evacuated before the start of next maturation stage. The experiments were conducted at ten different maturity stages (0.65 to 2.02 % Ro) from a terrestrial shaly coal with 0.48 % Ro. The gas products were analyzed by GC-IR-MS. The results show that, in general, the δ13C values of methane (C1), ethane (C2), propane (C3) slightly increase, then decrease and finally increase with increasing maturities. This reverse phenomenon indicates the heterogeneous and complex compositions of the kerogen. The isotope compositions of gases exhibit three distinct clusters in natural gas plot of δ13C values versus 1/n (where n is carbon number of the gaseous molecule), corresponding to three different groups of maturity stages. By linking the same maturity stage of δ13C values, all lines show nearly parallel in each group with consistently reverse trend of δ13C3 < δ13C2 > δ13C1. These three distinct clusters were also observed in the cross plotting of iC4/nC4 versus iC5/nC5 isomer ratios. This may imply that the kerogen is composed of three discrete structural domains which were progressively cracked at three major groups of maturity stages. The reverse trend was inconsistent with data for gas collected cumulatively in most prior pyrolysis experiments and the linear relationship predicted from kinetic isotope effect (KIE) model. Although the non-linear relationship or reverse trend, δ13C3 < δ13C2, was also reported for some natural gases, it was interpreted as a result of mixing from different source rocks or other

  20. Slurry growth, gas retention, and flammable gas generation by Hanford radioactive waste tanks: Synthetic waste studies, FY 1991

    SciTech Connect

    Bryan, S.A.; Pederson, L.R.; Ryan, J.L.; Scheele, R.D.; Tingey, J.M.

    1992-08-01

    Of 177 high-level waste storage tanks on the Hanford Site, 23 have been placed on a safety watch list because they are suspected of producing flammable gases in flammable or explosive concentrate. One tankin particular, Tank 241-SY-101 (Tank 101-SY), has exhibited slow increases in waste volume followed by a rapid decrease accompanied by venting of large quantities of gases. The purpose of this study is to help determine the processes by which flammable gases are produced, retained, and eventually released from Tank 101-SY. Waste composition data for single- and double-shell waste tanks on the flammable gas watch listare critically reviewed. The results of laboratory studies using synthetic double-shell wastes are summarized, including physical and chemical properties of crusts that are formed, the stoichiometry and rate ofgas generation, and mechanisms responsible for formation of a floating crust.

  1. Design study of an advanced gas generator. [which can be ignited during start-up period of turbine engines

    NASA Technical Reports Server (NTRS)

    Kim, S.; Trinh, H. P.

    1993-01-01

    A gas generator which can be ignited reliably during the initial start-up period and offers fairly uniform gas temperature at the exit was studied numerically. Various sizes and shapes of the mixing enhancement devices and their positions were examined to evaluate the uniformity of the exit gas temperature and the change of internal pressure drop incurred by introducing the mixing enhancement devices. By introducing a turbulence ring and a splash plate with an appropriate size and position, it was possible to obtain fairly uniform gas temperature distributions and a maximum gas temperature that is within the design limit temperature of 1600 R at the generator exit. However, with the geometry studied, the pressure drop across the generator was great, approximately 1150 psi, to satisfy the assigned design limit temperature. If the design limit temperature is increased to 1650 R, the pressure drop across the generator could be lowered by as much as 350 psi.

  2. Theoretical investigation on generating terahertz radiation from gas plasma induced by three-color ultrashort lasers

    NASA Astrophysics Data System (ADS)

    Wang, Cheng-Liang; Yang, Zhen-Gang; Liu, Jin-Song; Wang, Sheng-Lie; Wang, Ke-Jia

    2015-08-01

    Generation of intense broadband terahertz (THz) waves from gas plasma induced by tri-color ultrashort (fundamental (ω), second harmonic (2ω), and third harmonic (3ω)) laser pulses is theoretically investigated. Simulation results show that the 3ω laser pulse can greatly enhance or suppress the generation of THz wave at different values of relative phase (θ 3) between the 3ω and ω fields. Moreover, the polarities of the generated THz waves can be controlled by changing θ 3, with the relative phase θ 2 (between the 2ω and ω fields) fixed to be a certain value. All of our results show that θ 3 plays a key role in the generation process, which promises to control the intensity as well as the polarity of gas plasma-induced THz radiation. Project supported by the Wuhan Applied Basic Research Project, China (Grant No. 20140101010009), the National Natural Science Foundation of China (Grant Nos. 61177095, 61475054, and 61405063), the Natural Science Foundation of Hubei Province, China (Grant Nos. 2012FFA074 and 2013BAA002), the Fundamental Research Funds for the Central Universities, China (Grant Nos. 2013KXYQ004, 2014ZZGH021, and 2014QN023), and the Technology Innovation Foundation from Innovation Institute of Huazhong University of Science and Technology, China (Grant No. CXY13Q015).

  3. Modeling natural gas prices as a random walk: The advantages for generation planning

    SciTech Connect

    Felder, F.A.

    1995-11-01

    Random walk modeling allows decision makers to evaluate risk mitigation strategies. Easily constructed, the random walk provides probability information that long-term fuel forecasts do not. This is vital to meeting the ratepayers` need for low-cost power, the shareholders` financial objectives, and the regulators` desire for straightforward information. Power generation planning depends heavily on long-term fuel price forecasts. This is particularly true for natural gas-fired plants, because fuel expenses are a significant portion of busbar costs and are subject to considerable uncertainty. Accurate forecasts, then, are critical - especially if electric utilities are to take advantage of the current low cost of natural gas technologies and their relatively clean burning characteristics, without becoming overdependent on a fuel that might significantly increase in price. Moreover, the transition to a more competitive generation market requires a more market-driven planning process. Current planning techniques use several long-term fuel forecasts - one serving as an expected case and others for sensitivity analysis - as inputs for modeling production costs. These forecasts are deterministic: For every time interval there is one, and only one projected fuel price - a serious limitation. Further, past natural gas price predictions have been erroneous and may be susceptible to bias. Today, deregulation of the natural gas production industry allows for a new approach in long-term fuel forecasting. Using NYMEX information, a random walk model of natural gas prices can be constructed. A random walk assumes that prices move randomly, and in modeling prices in this context one would be sure to include this all-important price volatility.

  4. Modeling and experiments on differential pumping in linear plasma generators operating at high gas flows

    SciTech Connect

    Eck, H. J. N. van; Koppers, W. R.; Rooij, G. J. van; Goedheer, W. J.; Cardozo, N. J. Lopes; Kleyn, A. W.; Engeln, R.; Schram, D. C.

    2009-03-15

    The direct simulation Monte Carlo (DSMC) method was used to investigate the efficiency of differential pumping in linear plasma generators operating at high gas flows. Skimmers are used to separate the neutrals from the plasma beam, which is guided from the source to the target by a strong axial magnetic field. In this way, the neutrals are prevented to reach the target region. The neutral flux to the target must be lower than the plasma flux to enable ITER relevant plasma-surface interaction (PSI) studies. It is therefore essential to control the neutral gas dynamics. The DSMC method was used to model the expansion of a hot gas in a low pressure vessel where a small discrepancy in shock position was found between the simulations and a well-established empirical formula. Two stage differential pumping was modeled and applied in the linear plasma devices Pilot-PSI and PLEXIS. In Pilot-PSI a factor of 4.5 pressure reduction for H{sub 2} has been demonstrated. Both simulations and experiments showed that the optimum skimmer position depends on the position of the shock and therefore shifts for different gas parameters. The shape of the skimmer has to be designed such that it has a minimum impact on the shock structure. A too large angle between the skimmer and the forward direction of the gas flow leads to an influence on the expansion structure. A pressure increase in front of the skimmer is formed and the flow of the plasma beam becomes obstructed. It has been shown that a skimmer with an angle around 53 deg. gives the best performance. The use of skimmers is implemented in the design of the large linear plasma generator Magnum-PSI. Here, a three stage differentially pumped vacuum system is used to reach low enough neutral pressures near the target, opening a door to PSI research in the ITER relevant regime.

  5. Support and control system of the Waste Isolation Pilot Plant gas generation experiment glovebox

    SciTech Connect

    Benjamin, W.W.; Knight, C.J.; Michelbacher, J.A.; Rosenberg, K.E.

    1997-09-01

    A glovebox was designed and fabricated to house test containers loaded with contact handled transuranic (CH-TRU) waste. The test containers were designed to simulate the environmental characteristics of the caverns at the Waste Isolation Pilot Plant (WIPP). The support and control systems used to operate and maintain the Gas Generation Experiment (GGE) include the following: glovebox atmosphere and pressure control, test container support, glovebox operation support, and gas supply and exhaust systems. The glovebox atmosphere and pressure control systems consist of various components used to control both the pressure and quality of the argon atmosphere inside the glovebox. The glovebox pressure is maintained by three separate pressure control systems. The primary pressure control system is designed to maintain the glovebox at a negative pressure with the other two control systems serving as redundant safety backups. The quality of the argon atmosphere is controlled using a purifying bed system that removes oxygen and moisture. Glovebox atmosphere contaminants that are monitored on a continuous or periodic basis include moisture, oxygen, and nitrogen. The gas generation experiment requires the test containers to be filled with brine, leak tested, maintained at a constant temperature, and the gas head space of the test container sampled on a periodic basis. Test container support systems consisting of a brine addition system, leak test system, heating system, and gas sampling system were designed and implemented. A rupture disk system was constructed to provide pressure relief to the test containers. Operational requirements stipulated that test container temperature and pressure be monitored and collected on a continuous basis. A data acquisition system (DAS) was specifically designed to meet these requirements.

  6. Evaluation of Start Transient Oscillations with the J-2X Engine Gas Generator Assembly

    NASA Technical Reports Server (NTRS)

    Hulka, J. R.; Morgan, C. J.; Casiano, M. J.

    2015-01-01

    During development of the gas generator for the liquid oxygen/liquid hydrogen propellant J-2X rocket engine, distinctive and oftentimes high-amplitude pressure oscillations and hardware vibrations occurred during the start transient of nearly every workhorse gas generator assembly test, as well as during many tests of engine system hardware. These oscillations appeared whether the steady-state conditions exhibited stable behavior or not. They occurred similarly with three different injector types, and with every combustion chamber configuration tested, including chamber lengths ranging over a 5:1 range, several different nozzle types, and with or without a side branch line simulating a turbine spin start gas supply line. Generally, two sets of oscillations occurred, one earlier in the start transient and at higher frequencies, and the other almost immediately following and at lower frequencies. Multiple dynamic pressure measurements in the workhorse combustion chambers indicated that the oscillations were associated with longitudinal acoustic modes of the combustion chambers, with the earlier and higher frequency oscillation usually related to the second longitudinal acoustic mode and the later and lower frequency oscillation usually related to the first longitudinal acoustic mode. Given that several early development gas generator assemblies exhibited unstable behavior at frequencies near the first longitudinal acoustic modes of longer combustion chambers, the start transient oscillations are presumed to provide additional insight into the nature of the combustion instability mechanisms. Aspects of the steadystate oscillations and combustion instabilities from development and engine system test programs have been reported extensively in the three previous JANNAF Liquid Propulsion Subcommittee meetings (see references below). This paper describes the hardware configurations, start transient sequence operations, and transient and dynamic test data during the start

  7. A three-dimensional grid generation method for gas-turbine combustor flow computations

    NASA Astrophysics Data System (ADS)

    Shyy, Wei; Braaten, Mark E.; Sober, Janet S.

    1987-02-01

    A special-purpose code suitable for generating a curvilinear nonorthogonal grid system for gas-turbine combustor flow computations has been produced. The code is capable of handling an arbitrary number of dilution holes with any radii as well as film-cooling slots on the top and bottom surfaces. A zonal approach has been developed to handle the fast length scale variations imposed by the geometric constraints and to minimize the overall computational efforts needed to generate the grids. The code combines partial differential equation and algebraic interpolation methods to generate the grid system. The salient features of the grid characteristics are discussed. Also included are sample results of a 3-D turbulent combusting flow field calculated on the grid system produced by this methodology.

  8. Development of an axial microturbine for a portable gas turbine generator

    NASA Astrophysics Data System (ADS)

    Peirs, Jan; Reynaerts, Dominiek; Verplaetsen, Filip

    2003-07-01

    A miniature gas turbine is under development with the aim of generating electrical energy from fuel. This system consists of a compressor, combustion chamber, turbine and generator. The turbine is a single-stage axial impulse turbine (Laval turbine) with a rotor diameter of 10 mm, made of stainless steel using die-sinking electro-discharge machining. It has been tested with compressed air to speeds up to 160 000 rpm and generates a maximum mechanical power of 28 W with an efficiency of 18.4%. When coupled to a small generator, it generates 16 W of electrical power, which corresponds to an efficiency for the total system of 10.5%. The power density is mainly limited by the maximal speed of the ball bearings. The main losses are the blade profile losses and the exit losses. Higher speeds can considerably reduce the exit losses and therefore increase efficiency and power density. An improved turbine has been tested at temperatures up to 360 °C and generates up to 44 W of electrical energy with a total efficiency of 16%. A 20 mm diameter centrifugal compressor matching the pressure and flow characteristics of the turbine has been designed and is currently under construction.

  9. Piezoelectric transformers for low-voltage generation of gas discharges and ionic winds in atmospheric air

    SciTech Connect

    Johnson, Michael J.; Go, David B.

    2015-12-28

    To generate a gas discharge (plasma) in atmospheric air requires an electric field that exceeds the breakdown threshold of ∼30 kV/cm. Because of safety, size, or cost constraints, the large applied voltages required to generate such fields are often prohibitive for portable applications. In this work, piezoelectric transformers are used to amplify a low input applied voltage (<30 V) to generate breakdown in air without the need for conventional high-voltage electrical equipment. Piezoelectric transformers (PTs) use their inherent electromechanical resonance to produce a voltage amplification, such that the surface of the piezoelectric exhibits a large surface voltage that can generate corona-like discharges on its corners or on adjacent electrodes. In the proper configuration, these discharges can be used to generate a bulk air flow called an ionic wind. In this work, PT-driven discharges are characterized by measuring the discharge current and the velocity of the induced ionic wind with ionic winds generated using input voltages as low as 7 V. The characteristics of the discharge change as the input voltage increases; this modifies the resonance of the system and subsequent required operating parameters.

  10. Piezoelectric transformers for low-voltage generation of gas discharges and ionic winds in atmospheric air

    NASA Astrophysics Data System (ADS)

    Johnson, Michael J.; Go, David B.

    2015-12-01

    To generate a gas discharge (plasma) in atmospheric air requires an electric field that exceeds the breakdown threshold of ˜30 kV/cm. Because of safety, size, or cost constraints, the large applied voltages required to generate such fields are often prohibitive for portable applications. In this work, piezoelectric transformers are used to amplify a low input applied voltage (<30 V) to generate breakdown in air without the need for conventional high-voltage electrical equipment. Piezoelectric transformers (PTs) use their inherent electromechanical resonance to produce a voltage amplification, such that the surface of the piezoelectric exhibits a large surface voltage that can generate corona-like discharges on its corners or on adjacent electrodes. In the proper configuration, these discharges can be used to generate a bulk air flow called an ionic wind. In this work, PT-driven discharges are characterized by measuring the discharge current and the velocity of the induced ionic wind with ionic winds generated using input voltages as low as 7 V. The characteristics of the discharge change as the input voltage increases; this modifies the resonance of the system and subsequent required operating parameters.

  11. Transition metal catalysis in the generation of petroleum and natural gas

    NASA Astrophysics Data System (ADS)

    Mango, Frank D.

    1992-01-01

    Certain ratios of light hydrocarbons remain virtually invariant over the course of petroleum generation, indicating steady-state catalysis rather than thermal cracking as the central feature to the mechanism of petroleum generation. Although the evidence for catalytic intervention is now compelling, the nature of the catalytic agent, its mode of activation and action are not clear. I propose that the transition metals, activated in the lipophilic domains of kerogen, are the catalytic agents in the conversion of normal paraffins into light hydrocarbons and natural gas. The process proceeds through specific catalytic steps involving 3-, 5-, and 6-carbon ring-closures and the cleavage of carbon-carbon bonds in the key steps. This hypothesis is analyzed in the context of published literature on catalysis by Ni, V, Ti, Co, and related transition metals. Activated under anaerobic conditions, these metals express extraordinary catalytic activity in each of the postulated steps. Moreover, metal-catalysis provides a reasonable kinetic pathway through which hydrogen and normal paraffins may combine to form a methane-enriched natural gas. Given the anaerobic conditions of diagenesis and a kerogenous source of hydrogen, it is concluded that the transition metals, under catagenic conditions, are potentially active catalysts in the conversion of hydrogen and paraffins into light hydrocarbons and natural gas.

  12. Methane gas generation from waste water extraction process of crude palm oil in experimental digesters

    NASA Astrophysics Data System (ADS)

    Dillon, A.; Penafiel, R.; Garzón, P. V.; Ochoa, V.

    2015-12-01

    Industrial processes to extract crude palm oil, generates large amounts of waste water. High concentrations of COD, ST, SV, NH4 + and low solubility of O2, make the treatment of these effluents starts with anaerobic processes. The anaerobic digestion process has several advantages over aerobic degradation: lower operating costs (not aeration), low sludge production, methane gas generation. The 4 stages of anaerobic digestion are: hydrolysis, acidogenic, acetogenesis and methanogenesis. Through the action of enzymes synthesized by microbial consortia are met. The products of each step to serve as reagents is conducted as follows. The organic load times and cell hydraulic retention, solids content, nutrient availability, pH and temperature are factors that influence directly in biodigesters. The objectives of this presentation is to; characterize the microbial inoculum and water (from palm oil wasted water) to be used in biodigestores, make specific methanogenic activity in bioassays, acclimatize the microorganisms to produce methane gas using basal mineral medium with acetate for the input power, and to determine the production of methane gas digesters high organic load.

  13. Nitrogen Gas Plasma Generated by a Static Induction Thyristor as a Pulsed Power Supply Inactivates Adenovirus

    PubMed Central

    Sakudo, Akikazu; Toyokawa, Yoichi; Imanishi, Yuichiro

    2016-01-01

    Adenovirus is one of the most important causative agents of iatrogenic infections derived from contaminated medical devices or finger contact. In this study, we investigated whether nitrogen gas plasma, generated by applying a short high-voltage pulse to nitrogen using a static induction thyristor power supply (1.5 kilo pulse per second), exhibited a virucidal effect against adenoviruses. Viral titer was reduced by one log within 0.94 min. Results from detection of viral capsid proteins, hexon and penton, by Western blotting and immunochromatography were unaffected by the plasma treatment. In contrast, analysis using the polymerase chain reaction suggested that plasma treatment damages the viral genomic DNA. Reactive chemical products (hydrogen peroxide, nitrate, and nitrite), ultraviolet light (UV-A) and slight temperature elevations were observed during the operation of the gas plasma device. Viral titer versus intensity of each potential virucidal factor were used to identify the primary mechanism of disinfection of adenovirus. Although exposure to equivalent levels of UV-A or heat treatment did not inactivate adenovirus, treatment with a relatively low concentration of hydrogen peroxide efficiently inactivated the virus. Our results suggest the nitrogen gas plasma generates reactive chemical products that inactivate adenovirus by damaging the viral genomic DNA. PMID:27322066

  14. Transition metal catalysis in the generation of petroleum and natural gas

    SciTech Connect

    Mango, F.D. )

    1992-01-01

    Certain ratios of light hydrocarbons remain virtually invariant over the course of petroleum generation, indicating steady-state catalysis rather than thermal cracking as the central feature to the mechanism of petroleum generation. Although the evidence for catalytic intervention is now compelling, the nature of the catalytic agent, its mode of activation and action are not clear. The author proposes that the transition metals, activated in the lipophilic domains of kerogen, are the catalytic agents in the conversion of normal paraffins into light hydrocarbons and natural gas. The process proceeds through specific catalytic steps involving 3-, 5-, and 6-carbon ring-closures and the cleavage of carbon-carbon bonds in the key steps. This hypothesis is analyzed in the context of published literature on catalysis by Ni, V, Ti, Co, and related transition metals. Activated under anaerobic conditions, these metals express extraordinary catalytic activity in each of the postulated steps. Moreover, metal-catalysis provides a reasonable kinetic pathway through which hydrogen and normal paraffins may combine to form a methane-enriched a natural gas. Given the anaerobic conditions of diagenesis and a kerogenous source of hydrogen, it is concluded that the transition metals, under catagenic conditions, are potentially active catalysts in the conversion of hydrogen and paraffins into light hydrocarbons and natural gas.

  15. Nitrogen Gas Plasma Generated by a Static Induction Thyristor as a Pulsed Power Supply Inactivates Adenovirus.

    PubMed

    Sakudo, Akikazu; Toyokawa, Yoichi; Imanishi, Yuichiro

    2016-01-01

    Adenovirus is one of the most important causative agents of iatrogenic infections derived from contaminated medical devices or finger contact. In this study, we investigated whether nitrogen gas plasma, generated by applying a short high-voltage pulse to nitrogen using a static induction thyristor power supply (1.5 kilo pulse per second), exhibited a virucidal effect against adenoviruses. Viral titer was reduced by one log within 0.94 min. Results from detection of viral capsid proteins, hexon and penton, by Western blotting and immunochromatography were unaffected by the plasma treatment. In contrast, analysis using the polymerase chain reaction suggested that plasma treatment damages the viral genomic DNA. Reactive chemical products (hydrogen peroxide, nitrate, and nitrite), ultraviolet light (UV-A) and slight temperature elevations were observed during the operation of the gas plasma device. Viral titer versus intensity of each potential virucidal factor were used to identify the primary mechanism of disinfection of adenovirus. Although exposure to equivalent levels of UV-A or heat treatment did not inactivate adenovirus, treatment with a relatively low concentration of hydrogen peroxide efficiently inactivated the virus. Our results suggest the nitrogen gas plasma generates reactive chemical products that inactivate adenovirus by damaging the viral genomic DNA. PMID:27322066

  16. Peristaltic Micro-pump Generated from Heating Trapped Gas in a Superhydrophobic Microchannel

    NASA Astrophysics Data System (ADS)

    Hann, Sungyun; Kim, Tae Jin; Hidrovo, Carlos

    2013-11-01

    Study of micro-pumps has been actively pursued as they may be integrated into portable fluidic systems. Since one major application of developing portable fluidic devices is in medical drug delivery systems, the study of valveless micro-peristaltic pumps has attracted many researchers, particularly due to its low contamination risk of the working fluid. However, conventional peristaltic micro-pumps involve complex fabrication steps, including alignment of multiple device layers. The purpose of this research is to design a low cost, single layer peristaltic pump which utilizes thermal expansion of gas bubbles trapped in the microchannel walls. The microchannel walls are corrugated with a high roughness factor to prevent water from protruding into the gaps, thus rendering the surface superhydrophobic. The gas pockets are heated from the side walls, where the microheaters are fabricated by flowing molten metal into satellite microchannels and then solidifying them. We expect that the expanding gas pockets will act as a series of valves and that the fluid flow can be generated by sequentially heating the gas pockets along the microchannel.

  17. Using a Gas-Phase Tracer Test to Characterize the Impact of Landfill Gas Generation on Advective-Dispersive Transport of VOCs in the Vadose Zone

    PubMed Central

    Monger, Gregg R.; Duncan, Candice Morrison; Brusseau, Mark L.

    2015-01-01

    A gas-phase tracer test (GTT) was conducted at a landfill in Tucson, AZ, to help elucidate the impact of landfill gas generation on the transport and fate of chlorinated aliphatic volatile organic contaminants (VOCs). Sulfur hexafluoride (SF6) was used as the non-reactive gas tracer. Gas samples were collected from a multiport monitoring well located 15.2 m from the injection well, and analyzed for SF6, CH4, CO2, and VOCs. The travel times determined for SF6 from the tracer test are approximately two to ten times smaller than estimated travel times that incorporate transport by only gas-phase diffusion. In addition, significant concentrations of CH4 and CO2 were measured, indicating production of landfill gas. Based on these results, it is hypothesized that the enhanced rates of transport observed for SF6 are caused by advective transport associated with landfill gas generation. The rates of transport varied vertically, which is attributed to multiple factors including spatial variability of water content, refuse mass, refuse permeability, and gas generation. PMID:26380532

  18. Development of a dry low-NOx gas turbine combustor for a natural-gas fueled 2MW co-generation system

    SciTech Connect

    Mori, Masaaki; Sato, Hiroshi

    1998-07-01

    A dry low-NOx gas turbine combustor has been developed for natural-gas fueled co-generation systems in the power range of 1--4MW. The combustor. called the Double Swirler Combustor, uses the lean premixed combustion to reduce NOx emission. The combustor is characterized by two staged lean premixed combustion with two coaxial annular burners and a simple fuel control system without the complex variable geometry. Substantially low NOx level has been achieved to meet the strict NOx regulation to co-generation systems in Japan. High combustion efficiency has been obtained for a wide operating range. In 1994, Tokyo Gas and Ishikawajima-Harima Heavy Industries initiated a collaborative program to develop a natural-gas fueled low NOx gas turbine engine for new 2MW class co-generation system, named IM270. The Double Swirler Combustor, originally developed by Tokyo Gas, was introduced into the natural gas fueled version of the IM270. Engine test of the first production unit was successfully conducted to confirm substantially low NOx level of less than 15 ppm (O{sub 2} = 16%) with the output power of more than 2MW. Test for the durability and the reliability of the system is being conducted at Tokyo Gas Negishi LNG Terminal in Kanagawa, Japan and successful results have been so far obtained.

  19. Singlet Oxygen Generation on Porous Superhydrophobic Surfaces: Effect of Gas Flow and Sensitizer Wetting on Trapping Efficiency

    PubMed Central

    2015-01-01

    We describe physical-organic studies of singlet oxygen generation and transport into an aqueous solution supported on superhydrophobic surfaces on which silicon–phthalocyanine (Pc) particles are immobilized. Singlet oxygen (1O2) was trapped by a water-soluble anthracene compound and monitored in situ using a UV–vis spectrometer. When oxygen flows through the porous superhydrophobic surface, singlet oxygen generated in the plastron (i.e., the gas layer beneath the liquid) is transported into the solution within gas bubbles, thereby increasing the liquid–gas surface area over which singlet oxygen can be trapped. Higher photooxidation rates were achieved in flowing oxygen, as compared to when the gas in the plastron was static. Superhydrophobic surfaces were also synthesized so that the Pc particles were located in contact with, or isolated from, the aqueous solution to evaluate the relative effectiveness of singlet oxygen generated in solution and the gas phase, respectively; singlet oxygen generated on particles wetted by the solution was trapped more efficiently than singlet oxygen generated in the plastron, even in the presence of flowing oxygen gas. A mechanism is proposed that explains how Pc particle wetting, plastron gas composition and flow rate as well as gas saturation of the aqueous solution affect singlet oxygen trapping efficiency. These stable superhydrophobic surfaces, which can physically isolate the photosensitizer particles from the solution may be of practical importance for delivering singlet oxygen for water purification and medical devices. PMID:24885074

  20. Effects of Surfactant Contamination on the Next Generation Gas Trap for the ISS Internal Thermal Control System

    NASA Technical Reports Server (NTRS)

    Leimkuehler, Thomas O.; Lukens, Clark; Reeves, Daniel R.; Holt, James M.

    2004-01-01

    The current dual-membrane gas trap is designed to remove non-condensed gas bubbles from the Internal Thermal Control System (ITCS) coolant on board the International Space Station (ISS). To date it has successfully served its purpose of preventing gas bubbles from causing depriming, overspeed, and shutdown of the ITCS pump. However, contamination in the ITCS coolant has adversely affected the gas venting rate and lifetime of the gas trap, warranting a development effort for a next-generation gas trap. Previous testing has shown that a hydrophobic-only design is capable of performing even better than the current dual-membrane design for both steady-state gas removal and gas slug removal in clean deionized water. This paper presents results of testing to evaluate the effects of surfactant contamination on the steady-state performance of the hydrophobic-only design.

  1. Combustion Stability of the Gas Generator Assembly from J-2X Engine E10001 and Powerpack Tests

    NASA Technical Reports Server (NTRS)

    Hulka, J. R.; Kenny, R. L.; Casiano, M. J.

    2013-01-01

    Testing of a powerpack configuration (turbomachinery and gas generator assembly) and the first complete engine system of the liquid oxygen/liquid hydrogen propellant J-2X rocket engine have been completed at the NASA Stennis Space Center. The combustion stability characteristics of the gas generator assemblies on these two systems are of interest for reporting since considerable effort was expended to eliminate combustion instability during early development of the gas generator assembly with workhorse hardware. Comparing the final workhorse gas generator assembly development test data to the powerpack and engine system test data provides an opportunity to investigate how the nearly identical configurations of gas generator assemblies operate with two very different propellant supply systems one the autonomous pressure-fed test configuration on the workhorse development test stand, the other the pump-fed configurations on the powerpack and engine systems. The development of the gas generator assembly and the elimination of the combustion instability on the pressure-fed workhorse test stand have been reported extensively in the two previous Liquid Propulsion Subcommittee meetings 1-7. The powerpack and engine system testing have been conducted from mid-2011 through 2012. All tests of the powerpack and engine system gas generator systems to date have been stable. However, measureable dynamic behavior, similar to that observed on the pressure-fed test stand and reported in Ref. [6] and attributed to an injection-coupled response, has appeared in both powerpack and engine system tests. As discussed in Ref. [6], these injection-coupled responses are influenced by the interaction of the combustion chamber with a branch pipe in the hot gas duct that supplies gaseous helium to pre-spin the turbine during the start transient. This paper presents the powerpack and engine system gas generator test data, compares these data to the development test data, and provides additional

  2. High-harmonic generation in a quantum electron gas trapped in a nonparabolic and anisotropic well

    NASA Astrophysics Data System (ADS)

    Hurst, Jérôme; Lévêque-Simon, Kévin; Hervieux, Paul-Antoine; Manfredi, Giovanni; Haas, Fernando

    2016-05-01

    An effective self-consistent model is derived and used to study the dynamics of an electron gas confined in a nonparabolic and anisotropic quantum well. This approach is based on the equations of quantum hydrodynamics, which incorporate quantum and nonlinear effects in an approximate fashion. The effective model consists of a set of six coupled differential equations (dynamical system) for the electric dipole and the size of the electron gas. Using this model we show that: (i) high harmonic generation is related to the appearance of chaos in the phase space, as attested to by related Poincaré sections; (ii) higher order harmonics can be excited efficiently and with relatively weak driving fields by making use of chirped electromagnetic waves.

  3. Instrument Package Manipulation Through the Generation and Use of an Attenuated-Fluent Gas Fold

    NASA Technical Reports Server (NTRS)

    Breen, Daniel P.

    2012-01-01

    This document discusses a technique that provides a means for suspending large, awkward loads, instrument packages, components, and machinery in a stable, controlled, and precise manner. In the baseplate of the test machine, a pattern of grooves and ports is installed that when pressurized generates an attenuated- fluent gas fold providing a low-cost, near-zero-coefficient-of-friction lubrication boundary layer that supports the object evenly, and in a predictable manner. Package movement control requires minimal force. Aids to repeatable travel and positional accuracy can be added via the addition of simple guide bars and stops to the floor or object being moved. This allows easily regulated three-axis motions. Loads of extreme weight and size can be moved and guided by a single person, or by automated means, using minimal force. Upon removal of the attenuated fluent gas fold, the object returns to a stable resting position without impact forces affecting the object.

  4. An additional uncertainty of the throughput generated by the constant pressure gas flowmeter

    NASA Astrophysics Data System (ADS)

    Peksa, L.; Gronych, T.; Řepa, P.; Wild, J.; Tesař, J.; Pražák, D.; Krajíček, Z.; Vičar, M.

    2008-03-01

    The lower range limit of constant pressure gas flowmeters is about 10-8 Pa×m3/s. Detrimental gas throughputs caused by leaks and gassing from surfaces prevent from its decrease. Even if the flowmeter is entirely vacuum tight the throughput caused by the outgassing from surfaces can be sufficiently reduced only by pumping at elevated temperature. It can be performed with the flowmeters using directly driven bellows or diaphragm bellows in the volume displacers. Despite it, the lower range limit can hardly be decreased more than several ten times with up to now known designs. An additional uncertainty caused by the difference in pressure at the initial and final instant of measurement will increase at generating small throughputs to the extent that it will kill the measurement.

  5. Study on a novel semidry flue gas desulfurization with multifluid alkaline spray generator

    SciTech Connect

    Zhou, Y.G.; Zhang, M.C.; Wang, D.F.; Wang, L.

    2005-11-09

    The advantages and disadvantages of the typical semidry flue gas desulfurization (FGD) processes are analyzed, and a novel semidry FGD process with multifluid alkaline spray generator is first proposed to improve the colliding contact efficiency between sorbent particles and spray water droplets, and to form a large amount of aqueous lime slurry. The experimental results show that the colliding contact efficiency between lime particles and water droplets in the prefix alkaline spray generator may reach about 70%, which is significantly higher than the colliding contact efficiency of 25% in duct sorbent injection. The SO{sub 2} removal efficiency can reach 64.5% when the Ca/S molar ratio is 1.5, the approach to the saturation temperature is 10.3{sup o}C, and the flue gas residence time is 2.25 s. It is higher than that of in-duct sorbent injection under similar conditions, and the sorbent utilization is improved to 43%. Therefore, the FGD process with a prefix alkaline spray generator can greatly improve SO{sub 2} removal efficiency and sorbent utilization and it will be a new, simple and efficient semidry FGD process for industrial application in the future.

  6. Evaluation of an Integrated Gas-Cooled Reactor Simulator and Brayton Turbine-Generator

    NASA Technical Reports Server (NTRS)

    Hissam, David Andy; Stewart, Eric T.

    2006-01-01

    A closed-loop brayton cycle, powered by a fission reactor, offers an attractive option for generating both planetary and in-space electric power. Non-nuclear testing of this type of system provides the opportunity to safely work out integration and system control challenges for a modest investment. Recognizing this potential, a team at Marshall Space Flight Center has evaluated the viability of integrating and testing an existing gas-cooled reactor simulator and a modified commercially available, off-the-shelf, brayton turbine-generator. Since these two systems were developed independently of one another, this evaluation had to determine if they could operate together at acceptable power levels, temperatures, and pressures. Thermal, fluid, and structural analyses show that this combined system can operate at acceptable power levels and temperatures. In addition, pressure drops across the reactor simulator, although higher than desired, are also viewed as acceptable. Three potential working fluids for the system were evaluated: N2, He/Ar, and He/Xe. Other potential issues, such as electrical breakdown in the generator and the operation of the brayton foil bearings using various gas mixtures, were also investigated.

  7. Optimized working conditions for a thermoelectric generator as a topping cycle for gas turbines

    NASA Astrophysics Data System (ADS)

    Brady Knowles, C.; Lee, Hohyun

    2012-10-01

    This paper presents a model for a theoretical maximum efficiency of a thermoelectric generator integrated with a Brayton-cycle engine. The thermoelectric cycle is presented in two configurations as a topping cycle and a preheating topping cycle. For the topping cycle configuration, the thermoelectric generator receives heat from a high-temperature heat source and produces electrical work before rejecting heat to a Brayton cycle. For the preheating topping cycle, the rejected heat from the thermoelectric generator partially heats the compressed working fluid of the Brayton cycle before a secondary heater delivers heat to the working fluid directly from the heat source. The thermoelectric topping cycle efficiency increases as the temperature difference between the hot- and cold-side increases; however, this limits the heat transfer possible to the Brayton cycle, which in turn reduces power generation from the Brayton cycle. This model identifies the optimum operating parameters of the thermoelectric and Brayton cycles to obtain the maximum thermal efficiency of the combined cycle. In both configurations, efficiency gains are larger at low-temperature Brayton cycles. Although a thermoelectric generator (TEG) topping cycle enhances efficiency for a low temperature turbine, efficiency cannot exceed a high temperature gas turbine. Using a TEG topping cycle is limited to cases when space or price for a high temperature turbine cannot be justified. A design to achieve the preheating thermoelectric topping cycle is also presented.

  8. Analyses of Longitudinal Mode Combustion Instability in J-2X Gas Generator Development

    NASA Technical Reports Server (NTRS)

    Hulka, J. R.; Protz, C. S.; Casiano, M. J.; Kenny, R. J.

    2011-01-01

    The National Aeronautics and Space Administration (NASA) and Pratt & Whitney Rocketdyne are developing a liquid oxygen/liquid hydrogen rocket engine for future upper stage and trans-lunar applications. This engine, designated the J-2X, is a higher pressure, higher thrust variant of the Apollo-era J-2 engine. The contract for development was let to Pratt & Whitney Rocketdyne in 2006. Over the past several years, development of the gas generator for the J-2X engine has progressed through a variety of workhorse injector, chamber, and feed system configurations on the component test stand at the NASA Marshall Space Flight Center (MSFC). Several of the initial configurations resulted in combustion instability of the workhorse gas generator assembly at a frequency near the first longitudinal mode of the combustion chamber. In this paper, several aspects of these combustion instabilities are discussed, including injector, combustion chamber, feed system, and nozzle influences. To ensure elimination of the instabilities at the engine level, and to understand the stability margin, the gas generator system has been modeled at the NASA MSFC with two techniques, the Rocket Combustor Interaction Design and Analysis (ROCCID) code and a lumped-parameter MATLAB(TradeMark) model created as an alternative calculation to the ROCCID methodology. To correctly predict the instability characteristics of all the chamber and injector geometries and test conditions as a whole, several inputs to the submodels in ROCCID and the MATLAB(TradeMark) model were modified. Extensive sensitivity calculations were conducted to determine how to model and anchor a lumped-parameter injector response, and finite-element and acoustic analyses were conducted on several complicated combustion chamber geometries to determine how to model and anchor the chamber response. These modifications and their ramification for future stability analyses of this type are discussed.

  9. Conversion of Mixed Oxygenates Generated from Synthesis Gas to Fuel Range Hydrocarbon

    SciTech Connect

    Ramasamy, Karthikeyan K.; Gerber, Mark A.; Lilga, Michael A.; Flake, Matthew D.

    2012-08-19

    The growing dependence in the U.S. on foreign crude oil supplies and increased concerns regarding greenhouse gas emission has generated considerable interest in research to develop renewable and environmentally friendly liquid hydrocarbon transportation fuels. One of the strategies for achieving this is to produce intermediate compounds such as alcohols and other simple oxygenates from biomass generated synthesis gas (mixture of carbon monoxide and hydrogen) and further convert them into liquid hydrocarbons. The focus of this research is to investigate the effects of mixed oxygenates intermediate product compositions on the conversion step to produce hydrocarbon liquids. A typical mixed oxygenate stream is expected to contain water (around 50%), alcohols, such as methanol and ethanol (around 35%), and smaller quantities of oxygenates such as acetaldehyde, acetic acid and ethyl acetate. However the ratio and the composition of the mixed oxygenate stream generated from synthesis gas vary significantly depending on the catalyst used and the process conditions. Zeolite catalyzed deoxygenation of methanol accompanied by chain growth is well understood under Methanol-to-Gasoline (MTG) like reaction conditions using an H-ZSM-5 zeolite as the catalyst6-8. Research has also been conducted to a limited extent in the past with higher alcohols, but not with other oxygenates present9-11. Also there has been little experimental investigation into mixtures containing substantial amounts of water. The latter is of particular interest because water separation from the hydrocarbon product would be less energy intensive than first removing it from the oxygenate intermediate stream prior to hydrocarbon synthesis, potentially reducing overall processing costs.

  10. Effects of Globally Waste-Disturbing Activities on Gas Generation, Retention, and Release in Hanford Waste Tanks

    SciTech Connect

    Stewart, Charles W.; Huckaby, James L.; Meyer, Perry A.

    2003-07-30

    Various operations are authorized in Hanford tanks that disturb all or much of the waste. The globally waste-disturbing activities have the potential to release a large fraction of the retained flammable gas and to affect future gas generation, retention, and release behavior. This report presents analyses of the expected flammable gas release mechanisms and the potential release rates and volumes resulting from these activities. The background of the flammable gas safety issue at Hanford is summarized, as is the current understanding of gas generation, retention, and release phenomena. Considerations for gas monitoring and assessment of the potential for changes in tank classification and steady-state flammability are given. This revision (Rev. 2)incorporates additional comments from Office of River Protection reviewers. An appendix presents the checklist for technical peer review of Revision 1 of this report.

  11. Effects of Globally Waste-Disturbing Activities on Gas Generation, Retention, and Release in Hanford Waste Tanks

    SciTech Connect

    Stewart, Charles W.; Huckaby, James L.; Meyer, Perry A.

    2002-12-18

    Various operations are authorized in Hanford single- and double-shell tanks that disturb all or a large fraction of the waste. These globally waste-disturbing activities have the potential to release a large fraction of the retained flammable gas and to affect future gas generation, retention, and release behavior. This report presents analyses of the expected flammable gas release mechanisms and the potential release rates and volumes resulting from these activities. The background of the flammable gas safety issue at Hanford is summarized, as is the current understanding of gas generation, retention, and release phenomena. Considerations for gas monitoring and assessment of the potential for changes in tank classification and steady-state flammability are given.

  12. Method of making compost and spawned compost, mushroom spawn and generating methane gas

    SciTech Connect

    Stoller, B.B.

    1981-04-28

    Newly designed ribbon-type mixers provide an improved method for making composts, aerating composts, growing mushroom spawn, generating methane gas, and filling conveyors in the mushroom-growing industry. The mixers may be the double-ribbon type for purely mixing operations or the single-ribbon type for moving the material from one place to another. Both types can operate under pressure. In preparing compost for mushroom growing, operators can first use the airtight mixers for a preliminary anaerobic fermentation to produce methane, then by changing the atmosphere to an oxidizing one, complete the compost preparation under the necessary aerobic conditions.

  13. Conceptual design of a direct-contact natural-gas-fired downhole steam generator

    SciTech Connect

    Moreno, J.B.

    1982-06-01

    Conceptual designs are presented for three natural gas fueled, 1500 to 2000 psi, downhole steam generators: a 4 MMBtu/h unit sized for 7-inch casing, an 18.4 MMBtu/h unit sized for 7-inch casing, and an 18.4 MMBtu/h unit sized for 9-5/8-inch casing. Specifications for the support system for each system are outlined, considering both 3650-foot and 7000-foot well depths. Costs for major components and confidence levels for each design are estimated. Design philosophy and procedures are given in sufficient detail to enable extrapolation of or interpolation between the three designs.

  14. Conceptual design of a direct-contact natural-gas-fired downhole steam generator

    NASA Astrophysics Data System (ADS)

    Moreno, J. B.

    1982-06-01

    Conceptual designs are presented for three natural gas fueled, 1500 to 2000 psi, downhole steam generators: a 4 MMBtu/h unit sized for 7-inch casing, an 18.4 MMBtu/h unit sized for 7-inch casing, and an 18.4 MMBtu/h unit sized for 9-5/8 inch casing. Specifications for the support systems for each system are outlined, considering both 3650-foot and 7000-foot well depths. Costs for major components and confidence levels for each design are estimated. Design philosophy and procedures are given in sufficient detail to enable extrapolation of or interpolation between the three designs.

  15. Two-chamber hydrogen generation and application: access to pressurized deuterium gas.

    PubMed

    Modvig, Amalie; Andersen, Thomas L; Taaning, Rolf H; Lindhardt, Anders T; Skrydstrup, Troels

    2014-06-20

    Hydrogen and deuterium gas were produced and directly applied in a two-chamber system. These gaseous reagents were generated by the simple reaction of metallic zinc with HCl in water for H2 and DCl in deuterated water for D2. The setup proved efficient in classical Pd-catalyzed reductions of ketones, alkynes, alkenes, etc. in near-quantitative yields. The method was extended to the synthesis and isotope labeling of quinoline and 1,2,3,4-tetrahydroquinoline derivatives. Finally, CX-546 and Olaparib underwent efficient Ir-catalyzed hydrogen isotope exchange reactions. PMID:24870212

  16. Gas bubble formation in fused silica generated by ultra-short laser pulses.

    PubMed

    Cvecek, Kristian; Miyamoto, Isamu; Schmidt, Michael

    2014-06-30

    During processing of glass using ultra-fast lasers the formation of bubble-like structures can be observed in several glass types such as fused silica. Their formation can be exploited to generate periodic gratings in glasses but for other glass processing techniques such as waveguide-writing or glass welding by ultra-fast lasers the bubble formation proves often detrimental. In this work we present experiments and their results in order to gain understanding of the origins and on the underlying formation and transportation mechanisms of the gas bubbles. PMID:24977843

  17. Method for generating a highly reactive plasma for exhaust gas aftertreatment and enhanced catalyst reactivity

    DOEpatents

    Whealton, John H.; Hanson, Gregory R.; Storey, John M.; Raridon, Richard J.; Armfield, Jeffrey S.; Bigelow, Timothy S.; Graves, Ronald L.

    2002-01-01

    A method for non-thermal plasma aftertreatment of exhaust gases the method comprising the steps of providing short risetime, high frequency, high power bursts of low-duty factor microwaves sufficient to generate a plasma discharge and passing a gas to be treated through the discharge so as to cause dissociative reduction of the exhaust gases and enhanced catalyst reactivity through application of the pulsed microwave fields directly to the catalyst material sufficient to cause a polarizability catastrophe and enhanced heating of the metal crystallite particles of the catalyst, and in the presence or absence of the plasma. The invention also includes a reactor for aftertreatment of exhaust gases.

  18. Size-Dependent High-order Harmonic Generation in Rare-Gas Clusters

    NASA Astrophysics Data System (ADS)

    Park, Hyunwook; Wang, Zhou; Xiong, Hui; Schoun, Stephen B.; Xu, Junliang; Agostini, Pierre; DiMauro, Louis F.

    2014-12-01

    High-order harmonic generation (HHG) is investigated in rare-gas clusters as a function of the cluster size using 0.8 and 1.3 μ m femtosecond lasers. A characteristic, species-dependent knee structure in the single particle response is observed. A 1D recollision model qualitatively reproduces this behavior and associates it to the degree of delocalization of the initial wave function. Small clusters are observed to have a higher efficiency than monomers but rapidly lose this advantage as the size increases. The implications of these findings on the HHG mechanism in clusters are discussed.

  19. Numerical simulation of operation processes in the combustion chamber and gas generator of oxygen-methane liquid rocket engine

    NASA Astrophysics Data System (ADS)

    Kalmykov, G. P.; Larionov, A. A.; Sidlerov, D. A.; Yanchilin, L. A.

    2009-09-01

    The results of numerical simulations of processes in gas generators and combustion chambers operating on oxygen and methane are presented. Specific features of mixing, evaporation, and combustion of propellants have been investigated. The degree of combustion completeness in chambers with three types of injectors - coaxial-jet gas-liquid, liquid-liquid monopropellant, and bipropellant impinging-jets injectors - has been estimated.

  20. Effects of Self-generated Heat on Gas Sensing in Mobile Robots and Olfactory Sensing in Humans

    NASA Astrophysics Data System (ADS)

    Matsukura, Haruka; Wada, Yuta; Ishida, Hiroshi

    2011-09-01

    Mobile robots equipped with gas sensors have been applied to measure gas distributions in given areas. Here we present experimental results to show that the obtained distributions are, at least in some cases, distorted because of upward air currents created by self-generated heat of the robot. The results of CFD simulations show that human olfaction is also affected by upward air currents generated around our bodies.

  1. Life cycle water consumption and wastewater generation impacts of a Marcellus shale gas well.

    PubMed

    Jiang, Mohan; Hendrickson, Chris T; VanBriesen, Jeanne M

    2014-01-01

    This study estimates the life cycle water consumption and wastewater generation impacts of a Marcellus shale gas well from its construction to end of life. Direct water consumption at the well site was assessed by analysis of data from approximately 500 individual well completion reports collected in 2010 by the Pennsylvania Department of Conservation and Natural Resources. Indirect water consumption for supply chain production at each life cycle stage of the well was estimated using the economic input-output life cycle assessment (EIO-LCA) method. Life cycle direct and indirect water quality pollution impacts were assessed and compared using the tool for the reduction and assessment of chemical and other environmental impacts (TRACI). Wastewater treatment cost was proposed as an additional indicator for water quality pollution impacts from shale gas well wastewater. Four water management scenarios for Marcellus shale well wastewater were assessed: current conditions in Pennsylvania; complete discharge; direct reuse and desalination; and complete desalination. The results show that under the current conditions, an average Marcellus shale gas well consumes 20,000 m(3) (with a range from 6700 to 33,000 m(3)) of freshwater per well over its life cycle excluding final gas utilization, with 65% direct water consumption at the well site and 35% indirect water consumption across the supply chain production. If all flowback and produced water is released into the environment without treatment, direct wastewater from a Marcellus shale gas well is estimated to have 300-3000 kg N-eq eutrophication potential, 900-23,000 kg 2,4D-eq freshwater ecotoxicity potential, 0-370 kg benzene-eq carcinogenic potential, and 2800-71,000 MT toluene-eq noncarcinogenic potential. The potential toxicity of the chemicals in the wastewater from the well site exceeds those associated with supply chain production, except for carcinogenic effects. If all the Marcellus shale well wastewater is

  2. Life Cycle Water Consumption and Wastewater Generation Impacts of a Marcellus Shale Gas Well

    PubMed Central

    2013-01-01

    This study estimates the life cycle water consumption and wastewater generation impacts of a Marcellus shale gas well from its construction to end of life. Direct water consumption at the well site was assessed by analysis of data from approximately 500 individual well completion reports collected in 2010 by the Pennsylvania Department of Conservation and Natural Resources. Indirect water consumption for supply chain production at each life cycle stage of the well was estimated using the economic input–output life cycle assessment (EIO-LCA) method. Life cycle direct and indirect water quality pollution impacts were assessed and compared using the tool for the reduction and assessment of chemical and other environmental impacts (TRACI). Wastewater treatment cost was proposed as an additional indicator for water quality pollution impacts from shale gas well wastewater. Four water management scenarios for Marcellus shale well wastewater were assessed: current conditions in Pennsylvania; complete discharge; direct reuse and desalination; and complete desalination. The results show that under the current conditions, an average Marcellus shale gas well consumes 20 000 m3 (with a range from 6700 to 33 000 m3) of freshwater per well over its life cycle excluding final gas utilization, with 65% direct water consumption at the well site and 35% indirect water consumption across the supply chain production. If all flowback and produced water is released into the environment without treatment, direct wastewater from a Marcellus shale gas well is estimated to have 300–3000 kg N-eq eutrophication potential, 900–23 000 kg 2,4D-eq freshwater ecotoxicity potential, 0–370 kg benzene-eq carcinogenic potential, and 2800–71 000 MT toluene-eq noncarcinogenic potential. The potential toxicity of the chemicals in the wastewater from the well site exceeds those associated with supply chain production, except for carcinogenic effects. If all the Marcellus shale well

  3. Transition metal catalysis in the generation of petroleum and natural gas. Final report, September 1, 1992--October 31, 1995

    SciTech Connect

    Mango, F.D.

    1997-01-21

    This project originated on the premise that natural gas could be formed catalytically in the earth rather than thermally as commonly believed. The intention was to test this hypothetical view and to explore generally the role of sedimentary metals in the generation of light hydrocarbons (C1 - C9). We showed the metalliferous source rocks are indeed catalytic in the generation of natural gas. Various metal compounds in the pure state show the same levels of catalytic activity as sedimentary rocks and the products are identical. Nickel is particularly active among the early transition metals and is projected to remain catalytically robust at all stages of catagenesis. Nickel oxide promotes the formation of n-alkanes in addition to natural gas (NG), demonstrating the full scope of the hypothetical catalytic process. The composition of catalytic gas duplicates the entire range of natural gas, from so-called wet gas to dry gas (60 to 95+ wt % methane), while gas generated thermally is consistently depleted in methane (10 to 60 wt % methane). These results support the view that metal catalysis is a major pathway through which natural gas is formed in the earth.

  4. PV output smoothing using a battery and natural gas engine-generator.

    SciTech Connect

    Johnson, Jay; Ellis, Abraham; Denda, Atsushi; Morino, Kimio; Shinji, Takao; Ogata, Takao; Tadokoro, Masayuki

    2013-02-01

    In some situations involving weak grids or high penetration scenarios, the variability of photovoltaic systems can affect the local electrical grid. In order to mitigate destabilizing effects of power fluctuations, an energy storage device or other controllable generation or load can be used. This paper describes the development of a controller for coordinated operation of a small gas engine-generator set (genset) and a battery for smoothing PV plant output. There are a number of benefits derived from using a traditional generation resource in combination with the battery; the variability of the photovoltaic system can be reduced to a specific level with a smaller battery and Power Conditioning System (PCS) and the lifetime of the battery can be extended. The controller was designed specifically for a PV/energy storage project (Prosperity) and a gas engine-generator (Mesa Del Sol) currently operating on the same feeder in Albuquerque, New Mexico. A number of smoothing simulations of the Prosperity PV were conducted using power data collected from the site. By adjusting the control parameters, tradeoffs between battery use and ramp rates could be tuned. A cost function was created to optimize the control in order to balance, in this example, the need to have low ramp rates with reducing battery size and operation. Simulations were performed for cases with only a genset or battery, and with and without coordinated control between the genset and battery, e.g., without the communication link between sites or during a communication failure. The degree of smoothing without coordinated control did not change significantly because the battery dominated the smoothing response. It is anticipated that this work will be followed by a field demonstration in the near future.

  5. The combined application of impinger system and permeation tube for the generation of volatile organic compound standard gas mixtures at varying diluent flow rate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Commercial standard gas generators are often complex and expensive devices. The objective of this research was to assess the performance of a simplified glass impinger system for standard gas generation from a permeation tube (PT) device. The performance of the impinger standard gas generation syst...

  6. Experimental and theoretical studies of particle generation afterlaser ablation of copper with background gas at atmosphericpressure

    SciTech Connect

    Wen, Sy-Bor; Mao, Xianglei; Greif, Ralph; Russo, Richard E.

    2007-05-31

    Laser ablation has proven to be an effective method for generating nanoparticles; particles are produced in the laser induced vapor plume during the cooling stage. To understand the in-situ condensation process, a series of time resolved light scattering images were recorded and analyzed. Significant changes in the condensation rate and the shape of the condensed aerosol plume were observed in two background gases, helium and argon. The primary particle shape and size distribution were measured using a transmission electron microscope (TEM), a scanning electron microscope (SEM) and a differential mobility analyzer (DMA). The gas dynamics simulation included nucleation and coagulation within the vapor plume, heat and mass transfer from the vapor plume to the background gas, and heat transfer to the sample. The experimental data and the calculated evolution of the shape of the vapor plume showed the same trend for the spatial distribution of the condensed particles in both background gases. The simulated particle size distribution also qualitatively agreed with the experimental data. It was determined that the laser energy, the physical properties of the background gas (conductivity, diffusivity and viscosity), and the shape of the ablation system (ablation chamber and the layout of the sample) have strong effects on the condensation process and the subsequent sizes, shapes and degree of aggregation of the particles.

  7. A Petroleum Vapor Intrusion Model Involving Upward Advective Soil Gas Flow Due to Methane Generation.

    PubMed

    Yao, Yijun; Wu, Yun; Wang, Yue; Verginelli, Iason; Zeng, Tian; Suuberg, Eric M; Jiang, Lin; Wen, Yuezhong; Ma, Jie

    2015-10-01

    At petroleum vapor intrusion (PVI) sites at which there is significant methane generation, upward advective soil gas transport may be observed. To evaluate the health and explosion risks that may exist under such scenarios, a one-dimensional analytical model describing these processes is introduced in this study. This new model accounts for both advective and diffusive transport in soil gas and couples this with a piecewise first-order aerobic biodegradation model, limited by oxygen availability. The predicted results from the new model are shown to be in good agreement with the simulation results obtained from a three-dimensional numerical model. These results suggest that this analytical model is suitable for describing cases involving open ground surface beyond the foundation edge, serving as the primary oxygen source. This new analytical model indicates that the major contribution of upward advection to indoor air concentration could be limited to the increase of soil gas entry rate, since the oxygen in soil might already be depleted owing to the associated high methane source vapor concentration. PMID:26322369

  8. Waste drum gas generation sampling program at Rocky Flats during FY 1988

    SciTech Connect

    Roggenthen, D.K.; McFeeters, T.L.; Nieweg, R.G.

    1991-02-11

    Rocky Flats Plant Transuranic Waste Drums were sampled for gas composition. Combustibles, plastics, Raschig rings, solidified organic sludge, and solidified inorganic sludge transuranic waste forms were sampled. Plastic bag material and waste samples were also taken from some solidified sludge waste drums. A vacuum system was used to sample each layer of containment inside a waste drum, including individual waste bags. G values (gas generation) were calculated for the waste drums. Analytical results indicate that very low concentrations of potentially flammable or corrosive gas mixtures will be found in vented drums. G(H{sub 2}) was usually below 1.6, while G(Total) was below 4.0. Hydrogen permeability tests on different types of plastic waste bags used at Rocky Flats were also conducted. Polyvinylchloride was slightly more permeable to hydrogen than polyethylene for new or creased material. Permeability of aged material to hydrogen was slightly higher than for new material. Solidified organic and inorganic sludges were sampled for volatile organics. The analytical results from two drums of solidified organic sludges showed concentrations were above detection limits for four of the 36 volatile organics analyzed. The analytical results for four of the five solidified inorganic sludges show that concentrations were below detection limits for all volatile organics analyzed. 3 refs., 5 figs., 2 tabs.

  9. Simulations of Recent Ar Gas Puff Radiation Sources on the ZR Generator

    NASA Astrophysics Data System (ADS)

    Tangri, Varun; Harvey-Thompson, A. J.; Thornhill, J. W.; Giuliani, J. L.; Ouart, N. D.; Jones, B.; Jennings, C. A.

    2015-11-01

    We present radiation-magnetohydrodynamic simulations of four recent Ar gas puff shots on the refurbished Z generator. The simulations using Mach2-TCRE are calculated in r-z geometry with a tabulated collisional radiative equilibrium model for the non-LTE ionization kinetics and radiation transport. The four shots were designed to study the effects upon the Ar K-shell radiation output due to a change in the initial gas puff distribution. The shots Z2604 and Z2605 had a double shell puff and a central jet. The shots Z2560 and Z2628 did not have a central jet. Calculated yields are close to experimental error-bars. Results will be presented for the impact of the initial gas puff distribution on the K-shell yield. Work supported by the DOE/NNSA. SNL is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the U.S. Department of Energy's NNSA under contract DE-AC04-94AL85000.

  10. Pressure optimization of high harmonic generation in a differentially pumped Ar or H2 gas jet

    NASA Astrophysics Data System (ADS)

    Sayrac, M.; Kolomenskii, A. A.; Anumula, S.; Boran, Y.; Hart, N. A.; Kaya, N.; Strohaber, J.; Schuessler, H. A.

    2015-04-01

    We experimentally studied the dependence of high harmonic generation in argon and molecular hydrogen on pressure changes in a gas jet that cause variations of the phase matching conditions and absorption. The study was performed at a peak laser intensity of ˜1.5 × 1014 W/cm2. To enable measurements over a wide range of pressures, we employed differential pumping with an additional cell (˜20 cm3 volume) enclosing the gas jet. By increasing the pressure in the gas jet up to a maximum of 1.5 bars with argon or 0.5 bars with hydrogen, we observed an increase in the high harmonic (HH) yield until an optimum pressure of 0.2 bars was reached for Ar, beyond which the output began decreasing. For H2, we observed an increase of the HH output up to the maximum pressure of 0.5 bars. This pressure-dependence study allowed us to achieve a tenfold enhancement in the high harmonic yield at the optimum pressure.

  11. Deuterium Gas-Puff Z-Pinch on GIT-12 Generator

    NASA Astrophysics Data System (ADS)

    Klir, Daniel; Kravarik, Jozef; Kubes, Pavel; Rezac, Karel; Shishlov, Alexander; Kokshenev, Vladimir; Ratakhin, Nicolai; Kovalchuk, Boris; Labetsky, Aleksey; Kurmaev, Nikolay; Fursov, Fedor

    2011-10-01

    Deuterium gas-puff experiments have been carried out on the GIT-12 generator at the High Current Electronics Institute in Tomsk. During the initial experiment in May 2011, we used mainly double shell gas puffs with the outer and inner diameter of 100 and 30 mm, respectively. Single shell and shell-on-solid fill gas puffs were, however, also tested. The linear mass density of deuterium varied between 50 and 80 μg/cm. When a plasma-opening-switch (POS) was used, the current reached the peak of above 2.5 MA within 300 ns. The peak neutron yield from D(d,n)3He reactions exceeded 1011. In all shots, the neutron emission started during the stagnation. At the beginning of the neutron production, there was the correlation between the neutron emission and soft X-rays. Nevertheless, the peak of the neutron emission occurred 50 ns after the soft X-ray peak. At this very moment, hard X-rays above 1 MeV were detected. In the case of POS, > 800 keV widths of side-on neutron spectra implied > 200 keV deuterons moving in the radial direction. Work supported by the MSMT grants LA08024, ME09087, LC528.

  12. Impact of phytoplankton-generated surfactants on air-sea gas exchange

    NASA Astrophysics Data System (ADS)

    Frew, Nelson M.; Goldman, Joel C.; Dennett, Mark R.; Johnson, A. Sherwood

    1990-03-01

    The effect of surface-active organic matter generated by seven common species of marine phytoplankton on gas exchange rates under turbulent conditions at the air-water interface was determined. Reductions in oxygen evasion rates ranging from 5 to 50% were observed relative to clean seawater controls. Relative oxygen exchange coefficients (expressed as R = Kw [sample]/Kw [control]) were shown to be sensitive to small changes in total dissolved carbohydrate at concentrations <1 mg C (carbon) L-1 and to asymptotically decrease to a lower limit (R = 55-70%) at concentrations between 2 and 6 mg C L-1. A corresponding relationship was observed in which R decreased with increasing relative surfactant amounts derived from surface pressure-area measurements. However, gas exchange reductions were significant for plankton exudate samples displaying surface pressures ≲1 mN m-1. It thus seems that condensed monolayer films are not a prerequisite for reduced gas exchange and that relatively soluble surfactants derived from phytoplankton can strongly affect the dissipation of near-surface turbulence and lead to changes in the Schmidt number dependency of Kw. Based on detailed analyses of carbohydrate-containing surface-active exudates isolated by solid phase extraction from one of the species, Phaeodactylum tricornutum, it appears that small glucans and heteropolysaccharides associated with proteins and possibly lipids were responsible for the observed reductions in R.

  13. Fiber methane gas detector based on harmonic detection and application in ventilation air methane power generation

    NASA Astrophysics Data System (ADS)

    Li, Yanfang; Wei, Yubin; Shang, Ying; Zhao, Yanjie; Zhang, Tingting; Zhao, Weisong; Wang, Chang; Liu, Tongyu

    2010-10-01

    A fiber methane detector based on spectrum absorption is reported. The methane monitor use a distributed feedback diode lasers(DFB) which is near infrared spectroscopy as the optic source, we realized online harmonic detection of the methane. The advantages of this detector include high precision, elimination of interference from humidity and other gases as well as long recalibration cycle. The detection of CH4 is very important in the methane power generation. Especially the detection of the tail gas with high temperature is the dependence to judge the generator. In this paper, we give some data witch gained from the local of methane power generation. The data reach an agreement with the measurements of the sensor using in mine. And the detector has the function of self reference, so the detector is more depended. This proved that the fiber methane detector can meet the needs of the generator. It have some contribution to the production safety of the mine and the energy saving and emission reduction and the environmental protection.

  14. Modeled occupational exposures to gas-phase medical laser-generated air contaminants.

    PubMed

    Lippert, Julia F; Lacey, Steven E; Jones, Rachael M

    2014-01-01

    Exposure monitoring data indicate the potential for substantive exposure to laser-generated air contaminants (LGAC); however the diversity of medical lasers and their applications limit generalization from direct workplace monitoring. Emission rates of seven previously reported gas-phase constituents of medical laser-generated air contaminants (LGAC) were determined experimentally and used in a semi-empirical two-zone model to estimate a range of plausible occupational exposures to health care staff. Single-source emission rates were generated in an emission chamber as a one-compartment mass balance model at steady-state. Clinical facility parameters such as room size and ventilation rate were based on standard ventilation and environmental conditions required for a laser surgical facility in compliance with regulatory agencies. All input variables in the model including point source emission rates were varied over an appropriate distribution in a Monte Carlo simulation to generate a range of time-weighted average (TWA) concentrations in the near and far field zones of the room in a conservative approach inclusive of all contributing factors to inform future predictive models. The concentrations were assessed for risk and the highest values were shown to be at least three orders of magnitude lower than the relevant occupational exposure limits (OELs). Estimated values do not appear to present a significant exposure hazard within the conditions of our emission rate estimates. PMID:24762065

  15. Self-Assembled Nano-energetic Gas Generators based on Bi2O3

    NASA Astrophysics Data System (ADS)

    Hobosyan, Mkhitar; Trevino, Tyler; Martirosyan, Karen

    2012-10-01

    Nanoenergetic Gas-Generators are formulations that rapidly release a large amount of gaseous products and generate a fast moving thermal wave. They are mainly based on thermite systems, which are pyrotechnic mixtures of metal powders (fuel- Al, Mg, etc.) and metal oxides (oxidizer, Bi2O3, Fe2O3, WO3, MoO3 etc.) that can generate an exothermic oxidation-reduction reaction referred to as a thermite reaction. A thermite reaction releases a large amount of energy and can generate rapidly extremely high temperatures. The intimate contact between the fuel and oxidizer can be enhanced by use of nano instead of micro particles. The contact area between oxidizer and metal particles depends from method of mixture preparation. In this work we utilize the self-assembly processes, which use the electrostatic forces to produce ordered and self-organized binary systems. In this process the intimate contact significantly enhances and gives the ability to build an energetic material in molecular level, which is crucial for thepressure discharge efficiency of nano-thermites. The DTA-TGA, Zeta-size analysis and FTIR technique were performed to characterize the Bi2O3 particles. The self-assembly of Aluminum and Bi2O3 was conducted in sonic bath with appropriate solvents and linkers. The resultant thermite pressure discharge values were tested in modified Parr reactor. In general, the self-assembled thermites give much higher-pressure discharge values than the thermites prepared with conventional roll-mixing technique.

  16. Diagnostics of deuterium gas-puff z-pinch experiments on the GIT-12 generator

    NASA Astrophysics Data System (ADS)

    Cikhardt, J.; Klir, D.; Rezac, K.; Kubes, P.; Kravarik, J.; Batobolotova, B.; Sila, O.; Turek, K.; Shishlov, A.; Labetsky, A.; Kokshenev, V.; Chedizov, R.; Ratakhin, N.; Varlachev, V.; Garapatsky, A.; Dudkin, G.; Padalko, V.; GIT-12 Team

    2014-10-01

    Z-pinch experiments with a deuterium gas-puff and an outer plasma shell generated by plasma guns were carried out on the GIT-12 generator at the IHCE in Tomsk. Using this novel configuration of the load, the neutron yields from the DD reaction were significantly increased from 2×1011 up to 3×1012 neutrons per shot at the current level of about 3 MA. In addition to recent experiments, the threshold activation detectors were used in order to get the information about the energy spectrum of the generated neutrons. The copper, indium, and lead samples were irradiated by the pulse of the neutrons generated during the experimental shot. The decay radiation of the products from the reactions 63Cu(n,2n)62Cu, 115In(n, γ) 116 mIn and 206Pb (n,3n)204mPb was observed using gamma spectrometer. According to the used neutron ToF scintillation detectors, the energy of neutrons reaches up to 20 MeV. The work was supported by the MSMT of the Czech Republic research Programs No. ME090871, No. LG13029, by the GACR Grant No. P205/12/0454, Grant CRA IAEA No. 17088 and RFBR research Project No. 13-08-00479-a.

  17. By-product Generation through Electrical Discharge in CF3I Gas and its Effect to Insulation Characteristics

    NASA Astrophysics Data System (ADS)

    Takeda, Toshinobu; Matsuoka, Shigeyasu; Kumada, Akiko; Hidaka, Kunihiko

    CF3I gas, which is one of promising SF6 substitutions, is investigated from the view point of by-product generated in gas discharge, since its global warming potential (GWP) is quite low and its insulation performance is equivalent or superior to SF6 gas. The insulation performance of CF3I gas is examined through measuring sparkover voltage in various electric fields and flashover voltage on the surface of insulating material together with analyzing by-products of CF3I gas. Gas chromatography analysis shows that C2F6, C2F4, CHF3, C3F8, C3F6, and C2F5I are generated by the sparkover and the flashover. The sparkover voltage after 1300 times sparkover in uniform electric field is decreased by 11%. The flashover voltage for a virgin insulator in CF3I gas is almost equal to that in SF6 gas. The flashover voltage in CF3I gas is, however, 0.6 times lower than that in SF6 gas, when the number of surface flashover is increased.

  18. Generating singlet oxygen bubbles: a new mechanism for gas-liquid oxidations in water.

    PubMed

    Bartusik, Dorota; Aebisher, David; Ghafari, BiBi; Lyons, Alan M; Greer, Alexander

    2012-02-01

    Laser-coupled microphotoreactors were developed to bubble singlet oxygen [(1)O(2) ((1)Δ(g))] into an aqueous solution containing an oxidizable compound. The reactors consisted of custom-modified SMA fiberoptic receptacles loaded with 150 μm silicon phthalocyanine glass sensitizer particles, where the particles were isolated from direct contact with water by a membrane adhesively bonded to the bottom of each device. A tube fed O(2) gas to the reactor chambers. In the presence of O(2), singlet oxygen was generated by illuminating the sensitizer particles with 669 nm light from an optical fiber coupled to the top of the reactor. The generated (1)O(2) was transported through the membrane by the O(2) stream and formed bubbles in solution. In solution, singlet oxygen reacted with probe compounds (9,10-anthracene dipropionate dianion, trans-2-methyl-2-pentanoate anion, N-benzoyl-D,L-methionine, or N-acetyl-D,L-methionine) to give oxidized products in two stages. The early stage was rapid and showed that (1)O(2) transfer occurred via bubbles mainly in the bulk water solution. The later stage was slow; it arose only from (1)O(2)-probe molecule contact at the gas/liquid interface. A mechanism is proposed that involves (1)O(2) mass transfer and solvation, where smaller bubbles provide better penetration of (1)O(2) into the flowing stream due to higher surface-to-volume contact between the probe molecules and (1)O(2). PMID:22260325

  19. Theranostic gas-generating nanoparticles for targeted ultrasound imaging and treatment of neuroblastoma.

    PubMed

    Lee, Jangwook; Min, Hyun-Su; You, Dong Gil; Kim, Kwangmeyung; Kwon, Ick Chan; Rhim, Taiyoun; Lee, Kuen Yong

    2016-02-10

    The development of safe and efficient diagnostic/therapeutic agents for treating cancer in clinics remains challenging due to the potential toxicity of conventional agents. Although the annual incidence of neuroblastoma is not that high, the disease mainly occurs in children, a population vulnerable to toxic contrast agents and therapeutics. We demonstrate here that cancer-targeting, gas-generating polymeric nanoparticles are useful as a theranostic tool for ultrasound (US) imaging and treating neuroblastoma. We encapsulated calcium carbonate using poly(d,l-lactide-co-glycolide) and created gas-generating polymer nanoparticles (GNPs). These nanoparticles release carbon dioxide bubbles under acidic conditions and enhance US signals. When GNPs are modified using rabies virus glycoprotein (RVG) peptide, a targeting moiety to neuroblastoma, RVG-GNPs effectively accumulate at the tumor site and substantially enhance US signals in a tumor-bearing mouse model. Intravenous administration of RVG-GNPs also reduces tumor growth in the mouse model without the use of conventional therapeutic agents. This approach to developing theranostic agents with disease-targeting ability may provide useful strategy for the detection and treatment of cancers, allowing safe and efficient clinical applications with fewer side effects than may occur with conventional agents. PMID:26739549

  20. J-2X Gas Generator Development Testing at NASA Marshall Space Flight Center

    NASA Technical Reports Server (NTRS)

    Reynolds, D. C.; Hormonzian, Carlo

    2010-01-01

    NASA is developing a liquid oxygen/liquid hydrogen rocket engine for upper stage and trans-lunar applications of the Ares vehicles for the Constellation program. This engine, designated the J-2X, is a higher pressure, higher thrust variant of the Apollo-era J-2 engine. Development was contracted to Pratt & Whitney Rocketdyne in 2006. Over the past several years, two phases of testing have been completed on the development of the gas generator for the J-2X engine. The hardware has progressed through a variety of workhorse injector, chamber, and feed system configurations. Several of these configurations have resulted in combustion instability of the gas generator assembly. Development of the final configuration of workhorse hardware (which will ultimately be used to verify critical requirements on a component level) has required a balance between changes in the injector and chamber hardware in order to successfully mitigate the combustion instability without sacrificing other engine system requirements. This paper provides an overview of the two completed test series, performed at NASA s Marshall Space Flight Center. The requirements, facility setup, hardware configurations, and test series progression are detailed. Significant levels of analysis have been performed in order to provide design solutions to mitigate the combustion stability issues, and these are briefly covered. Also discussed are the results of analyses related to either anomalous readings or off-nominal testing throughout the two test series.

  1. Thermoelectric Power Generation System for Future Hybrid Vehicles Using Hot Exhaust Gas

    NASA Astrophysics Data System (ADS)

    Kim, Sun-Kook; Won, Byeong-Cheol; Rhi, Seok-Ho; Kim, Shi-Ho; Yoo, Jeong-Ho; Jang, Ju-Chan

    2011-05-01

    The present experimental and computational study investigates a new exhaust gas waste heat recovery system for hybrid vehicles, using a thermoelectric module (TEM) and heat pipes to produce electric power. It proposes a new thermoelectric generation (TEG) system, working with heat pipes to produce electricity from a limited hot surface area. The current TEG system is directly connected to the exhaust pipe, and the amount of electricity generated by the TEMs is directly proportional to their heated area. Current exhaust pipes fail to offer a sufficiently large hot surface area for the high-efficiency waste heat recovery required. To overcome this, a new TEG system has been designed to have an enlarged hot surface area by the addition of ten heat pipes, which act as highly efficient heat transfer devices and can transmit the heat to many TEMs. As designed, this new waste heat recovery system produces a maximum 350 W when the hot exhaust gas heats the evaporator surface of the heat pipe to 170°C; this promises great possibilities for application of this technology in future energy-efficient hybrid vehicles.

  2. Calculational technique to predict combustible gas generation in sealed radioactive waste containers

    SciTech Connect

    Flaherty, J.E.; Fujita, A.; Deltete, C.P.; Quinn, G.J.

    1986-05-01

    Certain forms of nuclear waste, when subjected to ionizing radiation, produce combustible mixtures of gases. The production of these gases in sealed radioactive waste containers represents a significant safety concern for the handling, shipment and storage of waste. The US Nuclear Regulatory Commission (NRC) acted on this safety concern in September 1984 by publishing an information notice requiring waste generators to demonstrate, by tests or measurements, that combustible mixtures of gases are not present in radioactive waste shipments; otherwise the waste must be vented within 10 days of shipping. A task force, formed by the Edison Electric Institute to evaluate these NRC requirements, developed a calculational method to quantify hydrogen gas generation in sealed containers. This report presents the calculational method along with comparisons to actual measured hydrogen concentrations from EPICOR II liners, vented during their preparation for shipment. As a result of this, the NRC recently altered certain waste shipment Certificates-Of-Compliance to allow calculations, as well as tests and measurements, as acceptable means of determining combustible gas concentration. This modification was due in part to work described herein.

  3. Theoretical and experimental results of a mesoscale electric power generation system from pressurized gas flow

    NASA Astrophysics Data System (ADS)

    Krähenbühl, D.; Zwyssig, C.; Weser, H.; Kolar, J. W.

    2009-09-01

    In many process applications where throttling is used to reduce pressure, the potential to obtain net work output is sacrificed to the throttling process. Examples are throttling valves of gas pipelines and conventional throttles in automotive applications or turbo expanders as used in cryogenic plants. With a new pressure reduction system that produces electricity while expanding the gas, the lost potential to obtain work output can be recovered. To achieve a high power density, this energy generation system requires an increased operating speed of the electrical machine and the turbomachinery. This paper presents a miniature compressed-air-to-electric-power system, based on a radial turbine with a rated rotational speed of 490 000 rpm and a rated electric power output of 150 W. A comprehensive description including turbine, diffuser and permanent magnet (PM) generator is given. Finally, measurements of the compressed-air-to-electric-power system with a maximum rotational speed of over 600 000 rpm, a maximum electric output power of 170 W, a maximum torque of 5.2 mN m and a turbine efficiency of 52% are presented.

  4. Regional jointing and hydrocarbon generation in Big Sandy gas field, Kentucky

    SciTech Connect

    Loar, S.J.

    1986-05-01

    Producing wells in the Big Sandy gas field depend on well-developed subsurface joint systems to enhance migration into the borehole. To examine the joint systems, the surface joints were studied. Statistical analysis revealed eight regional joint sets: N30/sup 0/W, N10/sup 0/W, N20/sup 0/E, N30/sup 0/E, N40/sup 0/E, N60/sup 0/E, N80/sup 0/E, and east-west. These sets have the same orientations as reservoir joints observed in oriented cores, indicating that they are part of the same systems. Field observations suggest that the regional joint sets formed in at least three phases, which can be classified as hydraulic, tectonic, and unloading. The timing of hydrocarbons was calculated from a subsidence curve for Devonian and younger formations, which was constructed on the basis of published isopach, conodont alteration index, and well data. Plotting the maturation of the Ohio Shale with the regional jointing phases shows that the hydraulic joint sets formed before hydrocarbon generation began, and that the tectonic joint sets formed while the Ohio Shale was in the oil window. The oil and wet gas generated from the Ohio Shale have since migrated through the subsurface joint systems into younger reservoirs.

  5. Effect of Propellant Flowrate and Purity on Carbon Deposition in LO2/Methane Gas Generators

    NASA Technical Reports Server (NTRS)

    Bossard, J. A.; Burkhardt, W. M.; Niiya, K. Y.; Braam, F.

    1989-01-01

    The generation and deposition of carbon was studied in the Carbon Deposition Program using subscale hardware with LO2/Liquid Natural Gas (LNG) and LO2/Methane propellants at low mixture ratios. The purpose of the testing was to evaluate the effect of methane purity and full scale injection density on carbon deposition. The LO2/LNG gas generator/preburner testing was performed at mixture ratios between 0.24 and 0.58 and chamber pressures from 5.8 to 9.4 MPa (840 to 1370 psia). A total of seven 200 second duration tests were performed. The LNG testing occurred at low injection densities, similar to the previous LO2/RP-1, LO2/propane, and LO2/methane testing performed on the carbon deposition program. The current LO2/methane test series occurred at an injection density factor of approximately 10 times higher than the previous testing. The high injection density LO2/methane testing was performed at mixture ratios between from 0.23 to 0.81 and chamber pressures from 6.4 to 15.2 MPa (925 to 2210 psia). A total of nine high injection density tests were performed. The testing performed demonstrated that low purity methane (LNG) did not produce any detectable change in carbon deposition when compared to pure methane. In addition, the C* performance and the combustion gas temperatures measured were similar to those obtained for pure methane. Similar results were obtained testing pure methane at higher propellant injection densities with coarse injector elements.

  6. Apples with apples: accounting for fuel price risk in comparisons of gas-fired and renewable generation

    SciTech Connect

    Bolinger, Mark; Wiser, Ryan

    2003-12-18

    For better or worse, natural gas has become the fuel of choice for new power plants being built across the United States. According to the US Energy Information Administration (EIA), natural gas combined-cycle and combustion turbine power plants accounted for 96% of the total generating capacity added in the US between 1999 and 2002--138 GW out of a total of 144 GW. Looking ahead, the EIA expects that gas-fired technology will account for 61% of the 355 GW new generating capacity projected to come on-line in the US up to 2025, increasing the nationwide market share of gas-fired generation from 18% in 2002 to 22% in 2025. While the data are specific to the US, natural gas-fired generation is making similar advances in other countries as well. Regardless of the explanation for (or interpretation of) the empirical findings, however, the basic implications remain the same: one should not blindly rely on gas price forecasts when comparing fixed-price renewable with variable-price gas-fired generation contracts. If there is a cost to hedging, gas price forecasts do not capture and account for it. Alternatively, if the forecasts are at risk of being biased or out of tune with the market, then one certainly would not want to use them as the basis for resource comparisons or investment decisions if a more certain source of data (forwards) existed. Accordingly, assuming that long-term price stability is valued, the most appropriate way to compare the levelized cost of these resources in both cases would be to use forward natural gas price data--i.e. prices that can be locked in to create price certainty--as opposed to uncertain natural gas price forecasts. This article suggests that had utilities and analysts in the US done so over the sample period from November 2000 to November 2003, they would have found gas-fired generation to be at least 0.3-0.6 cents/kWh more expensive (on a levelized cost basis) than otherwise thought. With some renewable resources, in particular wind

  7. Endwall shape modification using vortex generators and fences to improve gas turbine cooling and effectiveness

    NASA Astrophysics Data System (ADS)

    Gokce, Zeki Ozgur

    The gas turbine is one of the most important parts of the air-breathing jet engine. Hence, improving its efficiency and rendering it operable under high temperatures are constant goals for the aerospace industry. Two types of flow within the gas turbine are of critical relevance: The flow around the first row of stator blades (also known as the nozzle guide vane blade - NGV) and the cooling flow inside the turbine blade cooling channel. The subject of this thesis work was to search for methods that could improve the characteristics of these two types of flows, thus enabling superior engine performance. The innovative aspect of our work was to apply an endwall shape modification previously employed by non-aerospace industries for cooling applications, to the gas turbine cooling flow which is vital to aerospace propulsion. Since the costs of investigating the possible benefits of any idea via extensive experiments could be quite high, we decided to use computational fluid dynamics (CFD) followed by experimentation as our methodology. We decided to analyze the potential benefits of using vortex generators (VGs) as well as the rectangular endwall fence. Since the pin-fins used in cooling flow are circular cylinders, and since the boundary layer flow is mainly characterized by the leading edge diameter of the NGV blade, we modeled both the pin-fins and the NGV blade as vertical circular cylinders. The baseline case consisted of the cylinder(s) being subjected to cross flow and a certain amount of freestream turbulence. The modifications we made on the endwall consisted of rectangular fences. In the case of the cooling flow, we used triangular shaped, common flow up oriented, delta winglet type vortex generators as well as rectangular endwall fences. The channel contained singular cylinders as well as staggered rows of multiple cylinders. For the NGV flow, a rectangular endwall fence and a singular cylinder were utilized. Using extensive CFD modeling and analysis, we

  8. Aluminum/ammonia heat pipe gas generation and long term system impact for the Space Telescope's Wide Field Planetary Camera

    NASA Technical Reports Server (NTRS)

    Jones, J. A.

    1983-01-01

    In the Space Telescope's Wide Field Planetary Camera (WFPC) project, eight heat pipes (HPs) are used to remove heat from the camera's inner electronic sensors to the spacecraft's outer, cold radiator surface. For proper device functioning and maximization of the signal-to-noise ratios, the Charge Coupled Devices (CCD's) must be maintained at -95 C or lower. Thermoelectric coolers (TEC's) cool the CCD's, and heat pipes deliver each TEC's nominal six to eight watts of heat to the space radiator, which reaches an equilibrium temperature between -15 C to -70 C. An initial problem was related to the difficulty to produce gas-free aluminum/ammonia heat pipes. An investigation was, therefore, conducted to determine the cause of the gas generation and the impact of this gas on CCD cooling. In order to study the effect of gas slugs in the WFPC system, a separate HP was made. Attention is given to fabrication, testing, and heat pipe gas generation chemistry studies.

  9. Design and assembly of a catalyst bed gas generator for the catalytic decomposition of high concentration hydrogen peroxide propellants and the catalytic combustion of hydrocarbon/air mixtures

    NASA Technical Reports Server (NTRS)

    Lohner, Kevin A. (Inventor); Mays, Jeffrey A. (Inventor); Sevener, Kathleen M. (Inventor)

    2004-01-01

    A method for designing and assembling a high performance catalyst bed gas generator for use in decomposing propellants, particularly hydrogen peroxide propellants, for use in target, space, and on-orbit propulsion systems and low-emission terrestrial power and gas generation. The gas generator utilizes a sectioned catalyst bed system, and incorporates a robust, high temperature mixed metal oxide catalyst. The gas generator requires no special preheat apparatus or special sequencing to meet start-up requirements, enabling a fast overall response time. The high performance catalyst bed gas generator system has consistently demonstrated high decomposition efficiency, extremely low decomposition roughness, and long operating life on multiple test articles.

  10. Windage Power Loss in Gas Foil Bearings and the Rotor-Stator Clearance of High Speed Generators Operating in High Pressure Environments

    NASA Technical Reports Server (NTRS)

    Bruckner, Robert J.

    2009-01-01

    Closed Brayton Cycle (CBC) and Closed Supercritical Cycle (CSC) engines are prime candidates to convert heat from a reactor into electric power for robotic space exploration and habitation. These engine concepts incorporate a permanent magnet starter/generator mounted on the engine shaft along with the requisite turbomachinery. Successful completion of the long-duration missions currently anticipated for these engines will require designs that adequately address all losses within the machine. The preliminary thermal management concept for these engine types is to use the cycle working fluid to provide the required cooling. In addition to providing cooling, the working fluid will also serve as the bearing lubricant. Additional requirements, due to the unique application of these microturbines, are zero contamination of the working fluid and entirely maintenance-free operation for many years. Losses in the gas foil bearings and within the rotor-stator gap of the generator become increasingly important as both rotational speed and mean operating pressure are increased. This paper presents the results of an experimental study, which obtained direct torque measurements on gas foil bearings and generator rotor-stator gaps. Test conditions for these measurements included rotational speeds up to 42,000 revolutions per minute, pressures up to 45 atmospheres, and test gases of nitrogen, helium, and carbon dioxide. These conditions provided a maximum test Taylor number of nearly one million. The results show an exponential rise in power loss as mean operating density is increased for both the gas foil bearing and generator windage. These typical "secondary" losses can become larger than the total system output power if conventional design paradigms are followed. A nondimensional analysis is presented to extend the experimental results into the CSC range for the generator windage.

  11. Effects of current on droplet generation and arc plasma in gas metal arc welding

    NASA Astrophysics Data System (ADS)

    Hu, J.; Tsai, H. L.

    2006-09-01

    In gas metal arc welding (GMAW), a technology using pulsed currents has been employed to achieve the one-droplet-per-pulse (ODPP) metal transfer mode with the advantages of low average currents, a stable and controllable droplet generation, and reduced spatter. In this paper, a comprehensive model was developed to study the effects of different current profiles on the droplet formation, plasma generation, metal transfer, and weld pool dynamics in GMAW. Five types of welding currents were studied, including two constant currents and three wave form currents. In each type, the transient temperature and velocity distributions of the arc plasma and the molten metal, and the shapes of the droplet and the weld pool were calculated. The results showed that a higher current generates smaller droplets, higher droplet frequency, and higher electromagnetic force that becomes the dominant factor detaching the droplet from the electrode tip. The model has demonstrated that a stable ODPP metal transfer mode can be achieved by choosing a current with proper wave form for given welding conditions.

  12. Structure interaction due to thermal bowing of shrouds in steam generator of gas-cooled reactor

    SciTech Connect

    Woo, H.H.

    1981-01-01

    The design of the gas-cooled reactor steam generators includes a tube bundle support plate system which restrains and supports the helical tubes in the steam generator. The support system consists of an array of radially oriented, perforated plates through which the helical tube coils are wound. These support plates have tabs on their edges which fit into vertical slots in the inner and outer shrouds. When the helical tube bundle and support plates are installed in the steam generator, they most likely cannot fit evenly between the inner and outer shrouds. This imperfection leads to different gaps between two extreme sides of the tube bundle and the shrouds. With different gaps through the tube bundle height, the helium flow experiences different cooling effects from the tube bundle. Hence, the temperature distribution in the shrouds will be non-uniform circumferentially since their surrounding helium flow temperatures are varied. These non-uniform temperatures in the shrouds result in the phenomenon of thermal bowing of shrouds.

  13. Intensity Distribution of Laser Induced Plasma Generated at Different Ambient Gas Preassure

    NASA Astrophysics Data System (ADS)

    Sarmiento, Rafael; Cabanzo, Rafael; Mejia-Ospino, Enrique

    2008-04-01

    In this work, intensity distributions of laser induced plasmas have been measured by emission with two-dimensional spatial resolution and temporal resolution. The plasmas have been generated on the surfaces of steel samples at different pressures of air and argon, in the ranges from l*10-6 to 680 Torr. We compare the features of the intensity spatial and temporal distribution in the two ambient studied here. We observed that the maxima values of intensity are obtained when the pressure is maxima. The features of intensity distribution show a significant change with the ambient and gas pressure. Also, we have measured how change the size of the plasma plume with the pressure at two different ambient.

  14. Optimization of a RF-generated CF4/O2 gas plasma sterilization process.

    PubMed

    Lassen, Klaus S; Nordby, Bolette; Grün, Reinar

    2003-05-15

    A sterilization process with the use of RF-generated (13.56 MHz) CF(4)/O(2) gas plasma was optimized in regards to power, flow rate, exposure time, and RF-system type. The dependency of the sporicidal effect on the spore inoculum positioning in the chamber of the RF systems was also investigated. Dried Bacillus stearothermophilus ATCC 7953 endospores were used as test organisms. The treatments were evaluated on the basis of survival curves and corresponding D values. The only parameter found to affect the sterilization process was the power of the RF system. Higher power resulted in higher kill. Finally, when the samples were placed more than 3-8 cm away from a centrally placed electrode in System 2, the sporicidal effect was reduced. The results are discussed and compared to results from the present literature. The RF excitation source is evaluated to be more appropriate for sterilization processes than the MW source. PMID:12687716

  15. Terahertz generation by nonlinear mixing of laser pulses in a clustered gas

    SciTech Connect

    Kumar, Manoj; Tripathi, V. K.

    2011-05-15

    A scheme of terahertz (THz) generation by two collinear laser pulses of finite spot size in a clustered gas is investigated theoretically. The lasers quickly ionize the atoms of the clusters, converting them into plasma balls, and exert a ponderomotive force on the cluster electrons, producing a beat frequency longitudinal current of limited transverse extent. The current acts as an antenna to produce beat frequency terahertz radiation. As the cluster expands under the hydrodynamic pressure, plasma frequency of cluster electrons {omega}{sub pe} decreases and approaches {radical}(3) times the frequency of laser, resonant heating and expansion of clusters occurs. On further expansion of clusters as {omega}{sub pe} approaches {radical}(3) times the terahertz frequency, resonant enhancement in THz radiated power occurs.

  16. A reference protocol for comparing the biocidal properties of gas plasma generating devices

    NASA Astrophysics Data System (ADS)

    Shaw, A.; Seri, P.; Borghi, C. A.; Shama, G.; Iza, F.

    2015-12-01

    Growing interest in the use of non-thermal, atmospheric pressure gas plasmas for decontamination purposes has resulted in a multiplicity of plasma-generating devices. There is currently no universally approved method of comparing the biocidal performance of such devices and in the work described here spores of the Gram positive bacterium Bacillus subtilis (ATCC 6633) are proposed as a suitable reference biological agent. In order to achieve consistency in the form in which the biological agent in question is presented to the plasma, a polycarbonate membrane loaded with a monolayer of spores is proposed. The advantages of the proposed protocol are evaluated by comparing inactivation tests in which an alternative microorganism (methicillin resistant Staphylococcus aureus—MRSA) and the widely-used sample preparation technique of directly pipetting cell suspensions onto membranes are employed. In all cases, inactivation tests with either UV irradiation or plasma exposure were more reproducible when the proposed protocol was followed.

  17. Analyses of Injection-Coupled Combustion Instability from J-2X Gas Generator Development

    NASA Technical Reports Server (NTRS)

    Hulka, James R.; Kenny, R. Jeremy; Protz, Chris; Casiano, Matthew

    2011-01-01

    During development of the gas generator for the liquid oxygen/liquid hydrogen propellant J-2X rocket engine, combustion instabilities were observed near the frequency of the first longitudinal acoustic mode of the hot gas combustion chamber duct. These instabilities were similar to intermediate-frequency or buzz-type instabilities as described in historical programs, except for several aspects: 1) the frequencies were low, in the realm of chug; 2) at times the instability oscillation amplitudes were quite large, with peak-to-peak amplitudes exceeding 50% of the mean chamber pressure along with the appearance of harmonics; 3) the chamber excitation was related to but not exactly at the first longitudinal combustion chamber acoustic mode; and 4) the injector provided mass flow rate oscillations induced by capacitance and inertance effects in the injector rather than by organ pipe resonances of the coaxial oxidizer posts. This type of combustion instability is referred to as "injection coupling" because one critical driving source of the instability is mass flow rate oscillations from the injector. However, the type of injection coupling observed here is different than observed in previous instances of buzz instability with coaxial injectors, because of the lower frequencies and lack of influence from the oxidizer post organ pipe resonances. Test data and preliminary analyses of the initial combustion instabilities were presented in several papers at the 5th Liquid Propulsion Subcommittee meeting. Since that time, additional hot-fire tests with several new hardware configurations have been conducted, and additional analyses have been completed. The analytical models described in previous papers have been updated to include the influences of new geometrical configurations, including a different oxidizer injector manifold configuration and a branch pipe in the hot gas duct that supplies gaseous helium during the start transient to pre-spin the turbine. In addition, the

  18. On-line gas-free electrodialytic eluent generator for capillary ion chromatography.

    PubMed

    Yang, Bingcheng; Takeuchi, Masaki; Dasgupta, Purnendu K

    2008-01-01

    Both low- and high-pressure, gas-free, capillary-scale electrodialytic generators for eluents in ion chromatography are described. While the low-pressure devices rely on planar or tubular membranes, the high-pressure devices rely on ion-exchange beads used both as one-way ionic gates and as ball-on-seat valves to provide sealing. The high-pressure device is easily implemented in the form of a commercial cross fitting and can withstand at least 1400 psi. By design these devices do not produce gas in the eluent channel; hence, it is not necessary to remove gas afterward. With appropriate electrolytes and electrode polarities, such devices can produce either acid or base or salt. In regard to ionic transport, the behavior of these devices fully corresponds to that of a semiconductor diode. To our knowledge, this is the first time such complete equivalence of ion transport through ion-exchange media and with the more familiar example of electron transport through a semiconductor diode under both forward- and reverse-biased conditions have been demonstrated. Reverse bias can be applied to minimize/prevent Donnan-forbidden leakage or ion exchange. Even with 4 M KOH in the electrode compartments and 4 microL/min water flowing through the eluent channel, with a reverse bias of -12 V, the leakage KOH concentration is <30 microM, whereas the KOH concentration with zero voltage applied, herein after termed open circuit penetration (OCP), is 1600 microM. It is suggested that this OCP occurs not as much through Donnan-forbidden leakage but via ion exchange. Chromatograms and reproducibility data are presented for both isocratic and gradient chromatography, using ion-exchange, latex-modified, open tubular and packed monolithic columns. PMID:18062705

  19. Tritium generation and neutron measurements in Pd-Si under high deuterium gas pressure

    SciTech Connect

    Claytor, T.N.; Tuggle, D.G.; Menlove, H.O.

    1991-01-01

    This paper summarizes some of the methods applicable for low level tritium detection needed in the search for anomalous fusion in metal hydrides. It is also intended to further detail our tritium and neutron results that have been obtained with the Pd-Si-D system, originally presented at earlier workshops. A measure of reproducibility that was not evident in our previous work has been achieved partially due to the better detection sensitivity afforded by the use of low tritium deuterium and partially from the fact that the foil-wafer cells can be made with nearly identical electrical characteristics. This reproducibility has allowed us to narrow the optimum conditions for the experiment. While this experiment is rather different from the standard'' electrolytic cell or the Ti gas hydride experiment, similarities exist in that non equilibrium conditions are sought and the tritium generation levels are low and neutron emission is extremely weak. In contrast to many electrochemical cell experiments, the system used in these experiments is completely sealed during operation and uses no electrolyte. The major improvements to the experiment have been the use of vary low tritium deuterium for the hydriding and the replacement of the aluminum neutron counter tubes with ones of stainless steel. These changes have resulted in pronounced improvements to the detection systems since the background tritium level in the gas has been reduced by a factor of 300 and the neutron background has been decreased by a factor of 14. 16 refs., 8 figs., 1 tab.

  20. Slowing of Femtosecond Laser-Generated Nanoparticles in a Background Gas

    DOE PAGESBeta

    Rouleau, Christopher M.; Puretzky, Alexander A.; Geohegan, David B.

    2014-11-25

    The slowing of Pt nanoparticles in argon background gas was characterized by Rayleigh scattering imaging using a plume of nanoparticles generated by femtosecond laser through thin film ablation (fs-TTFA) of 20 nanometers-thick Pt films. The ablation was performed at threshold laser energy fluences for complete film removal to provide a well-defined plume consisting almost entirely of nanoparticles traveling with a narrow velocity distribution, providing a unique system to unambiguously characterize the slowing of nanoparticles during interaction with background gases. Nanoparticles of ~200 nm diameter were found to decelerate in background Ar gas with pressures less than 50 Torr in goodmore » agreement with a linear drag model in the Epstein regime. Based on this model, the stopping distance of small nanoparticles in the plume was predicted and tested by particle collection in an off-axis geometry, and size distribution analysis by transmission electron microscopy. These results permit a basis to interpret nanoparticle propagation through background gases in laser ablation plumes that contain mixed components.« less

  1. Slowing of Femtosecond Laser-Generated Nanoparticles in a Background Gas

    SciTech Connect

    Rouleau, Christopher M.; Puretzky, Alexander A.; Geohegan, David B.

    2014-11-25

    The slowing of Pt nanoparticles in argon background gas was characterized by Rayleigh scattering imaging using a plume of nanoparticles generated by femtosecond laser through thin film ablation (fs-TTFA) of 20 nanometers-thick Pt films. The ablation was performed at threshold laser energy fluences for complete film removal to provide a well-defined plume consisting almost entirely of nanoparticles traveling with a narrow velocity distribution, providing a unique system to unambiguously characterize the slowing of nanoparticles during interaction with background gases. Nanoparticles of ~200 nm diameter were found to decelerate in background Ar gas with pressures less than 50 Torr in good agreement with a linear drag model in the Epstein regime. Based on this model, the stopping distance of small nanoparticles in the plume was predicted and tested by particle collection in an off-axis geometry, and size distribution analysis by transmission electron microscopy. These results permit a basis to interpret nanoparticle propagation through background gases in laser ablation plumes that contain mixed components.

  2. Gas phase dynamics of laser-generated nanoparticle populations and its application to nanomaterials fabrication

    NASA Astrophysics Data System (ADS)

    Bulut, Mevlut

    Naturally occurring materials often derive their outstanding properties from optimal anisotropic arrangements of nanoscale constituents. This requires a hierarchical organization of matter over several length scales, which is difficult to achieve in artificial materials made by conventional physical and chemical methods. This dissertation explores the combination of laser and aerosol processes as a novel approach to make thin film materials with a level of microscopic organization similar to that found in nature. Through a systematic investigation of the behavior of the gas-phase dynamics of nanoparticles generated by laser ablation of solid target materials in background gases and a study of the physical processes involved in gas-phase nanoparticle processing, a new instrument integrating a laser ablation source and an aerosol spectrometer was designed and implemented. Film deposition and nanoparticle deposition processes can be manipulated independently affording greater flexibility for materials fabrication than other laser methods. The integrated laser-aerosol method is very flexible and can be used in the synthesis of a variety of materials. In this dissertation it is applied to the deposition of nanocomposite thin films comprising tetrahedral amorphous carbon (ta-C) with embedded metal nanoparticles. The controlled incorporation of metal nanoparticles enables the modulation of the electrical conductivity of ta-C over four orders of magnitude without significantly or adversely affecting its mechanical properties.

  3. The Case for Natural Gas Fueled Solid Oxide Fuel Cell Power Systems for Distributed Generation

    SciTech Connect

    Chick, Lawrence A.; Weimar, Mark R.; Whyatt, Greg A.; Powell, Michael R.

    2015-02-01

    Natural-gas-fueled solid oxide fuel cell (NGSOFC) power systems yield electrical conversion efficiencies exceeding 60% and may become a viable alternative for distributed generation (DG) if stack life and manufacturing economies of scale can be realized. Currently, stacks last approximately 2 years and few systems are produced each year because of the relatively high cost of electricity from the systems. If mass manufacturing (10,000 units per year) and a stack life of 15 years can be reached, the cost of electricity from an NGSOFC system is estimated to be about 7.7 ¢/kWh, well within the price of commercial and residential retail prices at the national level (9.9-10¢/kWh and 11-12 ¢/kWh, respectively). With an additional 5 ¢/kWh in estimated additional benefits from DG, NGSOFC could be well positioned to replace the forecasted 59-77 gigawatts of capacity loss resulting from coal plant closures due to stricter emissions regulations and low natural gas prices.

  4. Slowing of femtosecond laser-generated nanoparticles in a background gas

    SciTech Connect

    Rouleau, C. M.; Puretzky, A. A.; Geohegan, D. B.

    2014-11-24

    The slowing of Pt nanoparticles in argon background gas was characterized by Rayleigh scattering imaging using a plume of nanoparticles generated by femtosecond laser through thin film ablation of 20 nm-thick Pt films. The ablation was performed at threshold laser energy fluences for complete film removal to provide a well-defined plume consisting almost entirely of nanoparticles traveling with a narrow velocity distribution, providing a unique system to unambiguously characterize the slowing of nanoparticles during interaction with background gases. Nanoparticles of ∼200 nm diameter were found to decelerate in background Ar gas with pressures less than 50 Torr in good agreement with a linear drag model in the Epstein regime. Based on this model, the stopping distance of small nanoparticles in the plume was predicted and tested by particle collection in an off-axis geometry, and size distribution analysis by transmission electron microscopy. These results permit a basis to interpret nanoparticle propagation through background gases in laser ablation plumes that contain mixed components.

  5. Gas Generator Feedline Orifice Sizing Methodology: Effects of Unsteadiness and Non-Axisymmetric Flow

    NASA Technical Reports Server (NTRS)

    Rothermel, Jeffry; West, Jeffrey S.

    2011-01-01

    Engine LH2 and LO2 gas generator feed assemblies were modeled with computational fluid dynamics (CFD) methods at 100% rated power level, using on-center square- and round-edge orifices. The purpose of the orifices is to regulate the flow of fuel and oxidizer to the gas generator, enabling optimal power supply to the turbine and pump assemblies. The unsteady Reynolds-Averaged Navier-Stokes equations were solved on unstructured grids at second-order spatial and temporal accuracy. The LO2 model was validated against published experimental data and semi-empirical relationships for thin-plate orifices over a range of Reynolds numbers. Predictions for the LO2 square- and round-edge orifices precisely match experiment and semi-empirical formulas, despite complex feedline geometry whereby a portion of the flow from the engine main feedlines travels at a right-angle through a smaller-diameter pipe containing the orifice. Predictions for LH2 square- and round-edge orifice designs match experiment and semi-empirical formulas to varying degrees depending on the semi-empirical formula being evaluated. LO2 mass flow rate through the square-edge orifice is predicted to be 25 percent less than the flow rate budgeted in the original engine balance, which was subsequently modified. LH2 mass flow rate through the square-edge orifice is predicted to be 5 percent greater than the flow rate budgeted in the engine balance. Since CFD predictions for LO2 and LH2 square-edge orifice pressure loss coefficients, K, both agree with published data, the equation for K has been used to define a procedure for orifice sizing.

  6. Generating Singlet Oxygen Bubbles: A New Mechanism for Gas-Liquid Oxidations in Water

    PubMed Central

    Bartusik, Dorota; Aebisher, David; Ghafari, BiBi

    2012-01-01

    Laser-coupled microphotoreactors were developed to bubble singlet oxygen [1O2 (1Δg)] into an aqueous solution containing an oxidizable compound. The reactors consisted of custom-modified SMA fiber-optic receptacles loaded with 150-μm silicon phthalocyanine glass sensitizer particles, where the particles were isolated from direct contact with water by a membrane adhesively bonded to the bottom of each device. A tube fed O2 gas to the reactor chambers. In the presence of O2, singlet oxygen was generated by illuminating the sensitizer particles with 669-nm light from an optical fiber coupled to the top of the reactor. The generated 1O2 was transported through the membrane by the O2 stream and formed bubbles in solution. In solution, singlet oxygen reacted with probe compounds (either 9,10-anthracene dipropionate dianion, trans-2-methyl-2-pentanoate anion, N-benzoyl-D,L-methionine, and N-acetyl-D,L-methionine) to give oxidized products in two stages. The early stage was rapid and showed that 1O2 transfer occurred via bubbles mainly in the bulk water solution. The later stage was slow, it arose only from 1O2-probe molecule contact at the gas/liquid interface. A mechanism is proposed that involves 1O2 mass transfer and solvation, where smaller bubbles provide better penetration of 1O2 into the flowing stream due to higher surface-to-volume contact between the probe molecules and 1O2. PMID:22260325

  7. Low NO{sub x} turbine power generation utilizing low Btu GOB gas. Final report, June--August 1995

    SciTech Connect

    Ortiz, I.; Anthony, R.V.; Gabrielson, J.; Glickert, R.

    1995-08-01

    Methane, a potent greenhouse gas, is second only to carbon dioxide as a contributor to potential global warming. Methane liberated by coal mines represents one of the most promising under exploited areas for profitably reducing these methane emissions. Furthermore, there is a need for apparatus and processes that reduce the nitrogen oxide (NO{sub x}) emissions from gas turbines in power generation. Consequently, this project aims to demonstrate a technology which utilizes low grade fuel (CMM) in a combustion air stream to reduce NO{sub x} emissions in the operation of a gas turbine. This technology is superior to other existing technologies because it can directly use the varying methane content gases from various streams of the mining operation. The simplicity of the process makes it useful for both new gas turbines and retrofitting existing gas turbines. This report evaluates the feasibility of using gob gas from the 11,000 acre abandoned Gateway Mine near Waynesburg, Pennsylvania as a fuel source for power generation applying low NO{sub x} gas turbine technology at a site which is currently capable of producing low grade GOB gas ({approx_equal} 600 BTU) from abandoned GOB areas.

  8. Cost and greenhouse gas emission tradeoffs of alternative uses of lignin for second generation ethanol

    NASA Astrophysics Data System (ADS)

    Pourhashem, Ghasideh; Adler, Paul R.; McAloon, Andrew J.; Spatari, Sabrina

    2013-06-01

    Second generation ethanol bioconversion technologies are under demonstration-scale development for the production of lignocellulosic fuels to meet the US federal Renewable Fuel Standards (RFS2). Bioconversion technology utilizes the fermentable sugars generated from the cellulosic fraction of the feedstock, and most commonly assumes that the lignin fraction may be used as a source of thermal and electrical energy. We examine the life cycle greenhouse gas (GHG) emission and techno-economic cost tradeoffs for alternative uses of the lignin fraction of agricultural residues (corn stover, and wheat and barley straw) produced within a 2000 dry metric ton per day ethanol biorefinery in three locations in the United States. We compare three scenarios in which the lignin is (1) used as a land amendment to replace soil organic carbon (SOC); (2) separated, dried and sold as a coal substitute to produce electricity; and (3) used to produce electricity onsite at the biorefinery. Results from this analysis indicate that for life cycle GHG intensity, amending the lignin to land is lowest among the three ethanol production options (-25 to -2 g CO2e MJ-1), substituting coal with lignin is second lowest (4-32 g CO2e MJ-1), and onsite power generation is highest (36-41 g CO2e MJ-1). Moreover, the onsite power generation case may not meet RFS2 cellulosic fuel requirements given the uncertainty in electricity substitution. Options that use lignin for energy do so at the expense of SOC loss. The lignin-land amendment option has the lowest capital cost among the three options due to lower equipment costs for the biorefinery’s thermal energy needs and use of biogas generated onsite. The need to purchase electricity and uncertain market value of the lignin-land amendment could raise its cost compared to onsite power generation and electricity co-production. However, assuming a market value (50-100/dry Mg) for nutrient and soil carbon replacement in agricultural soils, and potentially

  9. Committing to coal and gas: Long-term contracts, regulation, and fuel switching in power generation

    NASA Astrophysics Data System (ADS)

    Rice, Michael

    Fuel switching in the electricity sector has important economic and environmental consequences. In the United States, the increased supply of gas during the last decade has led to substantial switching in the short term. Fuel switching is constrained, however, by the existing infrastructure. The power generation infrastructure, in turn, represents commitments to specific sources of energy over the long term. This dissertation explores fuel contracts as the link between short-term price response and long-term plant investments. Contracting choices enable power plant investments that are relationship-specific, often regulated, and face uncertainty. Many power plants are subject to both hold-up in investment and cost-of-service regulation. I find that capital bias is robust when considering either irreversibility or hold-up due to the uncertain arrival of an outside option. For sunk capital, the rental rate is inappropriate for determining capital bias. Instead, capital bias depends on the regulated rate of return, discount rate, and depreciation schedule. If policies such as emissions regulations increase fuel-switching flexibility, this can lead to capital bias. Cost-of-service regulation can shorten the duration of a long-term contract. From the firm's perspective, the existing literature provides limited guidance when bargaining and writing contracts for fuel procurement. I develop a stochastic programming framework to optimize long-term contracting decisions under both endogenous and exogenous sources of hold-up risk. These typically include policy changes, price shocks, availability of fuel, and volatility in derived demand. For price risks, the optimal contract duration is the moment when the expected benefits of the contract are just outweighed by the expected opportunity costs of remaining in the contract. I prove that imposing early renegotiation costs decreases contract duration. Finally, I provide an empirical approach to show how coal contracts can limit

  10. Evaluation of Characteristics of High Efficiency Power Generation Systems Utilizing Fermentation Gas of Simply Sorted Municipal Refuse

    NASA Astrophysics Data System (ADS)

    Pak, Pyong Sik

    This paper evaluates characteristics of two kinds of power generation systems utilizing fermentation gas of municipal refuse which is generated with use of a fermentation equipment of sorted refuse from ordinary collected garbage. In evaluation, a garbage incineration plant treating refuse of 100 t/d was adopted. The two systems investigated are the following systems: (a) gas engine power generation system (Sys-GE) and (b) steam turbine power generation system with super heater of steam (Sys-SH). The characteristics of two systems have been estimated together with the conventional steam turbine power generation system (Sys-C). It has been estimated that Sys-GE and Sys-SH has 2.11 and 2.55 times greater energy saving and CO2 reduction effect compared with Sys-C, respectively.

  11. Current and future greenhouse gas emissions associated with electricity generation in China: implications for electric vehicles.

    PubMed

    Shen, Wei; Han, Weijian; Wallington, Timothy J

    2014-06-17

    China's oil imports and greenhouse gas (GHG) emissions have grown rapidly over the past decade. Addressing energy security and GHG emissions is a national priority. Replacing conventional vehicles with electric vehicles (EVs) offers a potential solution to both issues. While the reduction in petroleum use and hence the energy security benefits of switching to EVs are obvious, the GHG benefits are less obvious. We examine the current Chinese electric grid and its evolution and discuss the implications for EVs. China's electric grid will be dominated by coal for the next few decades. In 2015 in Beijing, Shanghai, and Guangzhou, EVs will need to use less than 14, 19, and 23 kWh/100 km, respectively, to match the 183 gCO2/km WTW emissions for energy saving vehicles. In 2020, in Beijing, Shanghai, and Guangzhou EVs will need to use less than 13, 18, and 20 kWh/100 km, respectively, to match the 137 gCO2/km WTW emissions for energy saving vehicles. EVs currently demonstrated in China use 24-32 kWh/100 km. Electrification will reduce petroleum imports; however, it will be very challenging for EVs to contribute to government targets for GHGs emissions reduction. PMID:24853334

  12. MOX and MOX with 237Np/241Am Inert Fission Gas Generation Comparison in ATR

    SciTech Connect

    G. S. Chang; M. Robel; W. J. Carmack; D. J. Utterbeck

    2006-06-01

    The treatment of spent fuel produced in nuclear power generation is one of the most important issues to both the nuclear community and the general public. One of the viable options to long-term geological disposal of spent fuel is to extract plutonium, minor actinides (MA), and potentially long-lived fission products from the spent fuel and transmute them into short-lived or stable radionuclides in currently operating light-water reactors (LWR), thus reducing the radiological toxicity of the nuclear waste stream. One of the challenges is to demonstrate that the burnup-dependent characteristic differences between Reactor-Grade Mixed Oxide (RG-MOX) fuel and RG-MOX fuel with MA Np-237 and Am 241 are minimal, particularly, the inert gas generation rate, such that the commercial MOX fuel experience base is applicable. Under the Advanced Fuel Cycle Initiative (AFCI), developmental fuel specimens in experimental assembly LWR-2 are being tested in the northwest (NW) I-24 irradiation position of the Advanced Test Reactor (ATR). The experiment uses MOX fuel test hardware, and contains capsules with MOX fuel consisting of mixed oxide manufactured fuel using reactor grade plutonium (RG-Pu) and mixed oxide manufactured fuel using RG-Pu with added Np/Am. This study will compare the fuel neutronics depletion characteristics of Case-1 RG-MOX and Case-2 RG-MOX with Np/Am.

  13. Singlet oxygen generation in gas discharge for oxygen-iodine laser pumping

    NASA Astrophysics Data System (ADS)

    Lopaev, D. V.; Braginsky, O. V.; Klopovsky, K. S.; Kovalev, A. S.; Mankelevich, Yu. A.; Popov, N. A.; Rakhimov, A. T.; Rakhimova, T. V.; Vasilieva, A. N.

    2004-09-01

    The possibility of development of effective discharged singlet oxygen (SO) generator (DSOG) for oxygen-iodine laser (OIL) is studied in detail. Researches of kinetics of oxygen atoms and oxygen molecules in the lowest metastable singlet states have been carried out in the different discharges and its afterglow (DC discharges, E-beam controlled discharge and RF discharges) in both CW and pulsed mode in a wide range of conditions (pressures, gas mixtures, energy deposits etc.). The models developed for all the discharges have allowed us to analyze SO generation and loss mechanisms and to find out the key-parameters controlling the highest SO yield. It is shown that in addition to spatial plasma uniformity at low E/N and high specific energy deposit per oxygen molecule, DSOG must be oxygen atom free to avoid fast three-body quenching of SO by atomic oxygen with increasing pressure and thereby to provide pressure scaling (in tens Torrs) for applying to real OIL systems.

  14. Deformation and the timing of gas generation and migration in the eastern Brooks Range foothills, Arctic National Wildlife Refuge, Alaska

    USGS Publications Warehouse

    Parris, T.M.; Burruss, R.C.; O'Sullivan, P. B.

    2003-01-01

    Along the southeast border of the 1002 Assessment Area in the Arctic National Wildlife Refuge, Alaska, an explicit link between gas generation and deformation in the Brooks Range fold and thrust belt is provided through petrographic, fluid inclusion, and stable isotope analyses of fracture cements integrated with zircon fission-track data. Predominantly quartz-cemented fractures, collected from thrusted Triassic and Jurassic rocks, contain crack-seal textures, healed microcracks, and curved crystals and fluid inclusion populations, which suggest that cement growth occurred before, during, and after deformation. Fluid inclusion homogenization temperatures (175-250??C) and temperature trends in fracture samples suggest that cements grew at 7-10 km depth during the transition from burial to uplift and during early uplift. CH4-rich (dry gas) inclusions in the Shublik Formation and Kingak Shale are consistent with inclusion entrapment at high thermal maturity for these source rocks. Pressure modeling of these CH4-rich inclusions suggests that pore fluids were overpressured during fracture cementation. Zircon fission-track data in the area record postdeposition denudation associated with early Brooks Range deformation at 64 ?? 3 Ma. With a closure temperature of 225-240??C, the zircon fission-track data overlap homogenization temperatures of coeval aqueous inclusions and inclusions containing dry gas in Kingak and Shublik fracture cements. This critical time-temperature relationship suggests that fracture cementation occurred during early Brooks Range deformation. Dry gas inclusions suggest that Shublik and Kingak source rocks had exceeded peak oil and gas generation temperatures at the time structural traps formed during early Brooks Range deformation. The timing of hydrocarbon generation with respect to deformation therefore represents an important exploration risk for gas exploration in this part of the Brooks Range fold and thrust belt. The persistence of gas high at

  15. Generating and Synthesizing Information about Risks in Unconventional Oil and Gas Development

    NASA Astrophysics Data System (ADS)

    Wiseman, H.

    2013-12-01

    site construction and disclosure of all chemicals used at the well site. Governments should also consider requiring air emissions (including methane) monitoring near well sites. Regardless of who conducts monitoring and testing, states and the federal government should agree on the parameters that would be tested for in all water and air quality samples, and they should require reporting in the same units to allow for cross-state comparison. Finally, we must synthesize data produced by industry or states and organize and summarize it in a manner that is understandable to scientists and non-scientists alike. The risks of unconventional oil and gas development are perhaps most easily understood when organized by the stage of well development, and for each stage, specific risks could be identified. The federal government is, once again, the most likely candidate to produce and synthesize this information. Although nonprofit groups, industry actors, and state government could also aid in this task, certain stakeholders might question whether these entities' motives influenced data summaries. Generating and synthesizing information about the technologies and risks involved in unconventional oil and gas development will not be easy, or cheap. But it will be important if we are to sail forward rapidly through waters that no other country has charted.

  16. Air Quality Impacts of Greenhouse Gas Mitigation Technologies in the Power Generation and Transportation Sectors

    NASA Astrophysics Data System (ADS)

    Mac Kinnon, Michael

    Future efforts to mitigate the harmful impacts of climate change will include transitions to alternative technologies and fuels targeting reductions in greenhouse gas (GHG) emissions. Currently, economic sectors of greatest concern include transportation and power generation, which combined contribute over half of total U.S. GHG emissions. In addition to GHGs, displacement of conventional energy strategies will impact the emissions of various pollutant species with human health and environmental risks due to common generation processes and sources. In order to fully investigate the air quality (AQ) impacts of deploying various GHG mitigation technologies and fuels in coming decades, spatially and temporally resolved pollutant emissions fields are developed and utilized as input for simulations of atmospheric chemistry and transport via an advanced AQ model. Three areas of the U.S. are chosen for regional analyses in the year 2055. In order to characterize the evolution of regional energy sector emission drivers from current levels, a Base Case is developed that is representative of progression in the absence of aggressive GHG mitigation efforts. To facilitate comparison, alternative scenarios are developed to explore the effects of shifts in technologies, fuels, or behavior with the potential to mitigate GHG emissions. Scenarios are represented by generated spatially and temporally resolved emission fields and evaluated for impacts on primary and secondary air pollutant concentrations. Significant variation in energy profiles, demands, and constraints (e.g., regulatory statutes) between study domains yields significant differences in regional impacts. The magnitude of AQ improvements depends on baseline emission levels and spatial and temporal emission patterns. In addition, the current focus on reducing emissions from the targeted sectors increases the importance of emissions from other areas and sectors.

  17. Characterization of Tungsten Inert Gas (TIG) Welding Fume Generated by Apprentice Welders.

    PubMed

    Graczyk, Halshka; Lewinski, Nastassja; Zhao, Jiayuan; Concha-Lozano, Nicolas; Riediker, Michael

    2016-03-01

    Tungsten inert gas welding (TIG) represents one of the most widely used metal joining processes in industry. Its propensity to generate a greater portion of welding fume particles at the nanoscale poses a potential occupational health hazard for workers. However, current literature lacks comprehensive characterization of TIG welding fume particles. Even less is known about welding fumes generated by welding apprentices with little experience in welding. We characterized TIG welding fume generated by apprentice welders (N = 20) in a ventilated exposure cabin. Exposure assessment was conducted for each apprentice welder at the breathing zone (BZ) inside of the welding helmet and at a near-field (NF) location, 60cm away from the welding task. We characterized particulate matter (PM4), particle number concentration and particle size, particle morphology, chemical composition, reactive oxygen species (ROS) production potential, and gaseous components. The mean particle number concentration at the BZ was 1.69E+06 particles cm(-3), with a mean geometric mean diameter of 45nm. On average across all subjects, 92% of the particle counts at the BZ were below 100nm. We observed elevated concentrations of tungsten, which was most likely due to electrode consumption. Mean ROS production potential of TIG welding fumes at the BZ exceeded average concentrations previously found in traffic-polluted air. Furthermore, ROS production potential was significantly higher for apprentices that burned their metal during their welding task. We recommend that future exposure assessments take into consideration welding performance as a potential exposure modifier for apprentice welders or welders with minimal training. PMID:26464505

  18. Life Cycle Greenhouse Gas Emissions of Coal-Fired Electricity Generation: Systematic Review and Harmonization

    SciTech Connect

    Whitaker, M.; Heath, G. A.; O'Donoughue, P.; Vorum, M.

    2012-04-01

    This systematic review and harmonization of life cycle assessments (LCAs) of utility-scale coal-fired electricity generation systems focuses on reducing variability and clarifying central tendencies in estimates of life cycle greenhouse gas (GHG) emissions. Screening 270 references for quality LCA methods, transparency, and completeness yielded 53 that reported 164 estimates of life cycle GHG emissions. These estimates for subcritical pulverized, integrated gasification combined cycle, fluidized bed, and supercritical pulverized coal combustion technologies vary from 675 to 1,689 grams CO{sub 2}-equivalent per kilowatt-hour (g CO{sub 2}-eq/kWh) (interquartile range [IQR]= 890-1,130 g CO{sub 2}-eq/kWh; median = 1,001) leading to confusion over reasonable estimates of life cycle GHG emissions from coal-fired electricity generation. By adjusting published estimates to common gross system boundaries and consistent values for key operational input parameters (most importantly, combustion carbon dioxide emission factor [CEF]), the meta-analytical process called harmonization clarifies the existing literature in ways useful for decision makers and analysts by significantly reducing the variability of estimates ({approx}53% in IQR magnitude) while maintaining a nearly constant central tendency ({approx}2.2% in median). Life cycle GHG emissions of a specific power plant depend on many factors and can differ from the generic estimates generated by the harmonization approach, but the tightness of distribution of harmonized estimates across several key coal combustion technologies implies, for some purposes, first-order estimates of life cycle GHG emissions could be based on knowledge of the technology type, coal mine emissions, thermal efficiency, and CEF alone without requiring full LCAs. Areas where new research is necessary to ensure accuracy are also discussed.

  19. Characterization of Tungsten Inert Gas (TIG) Welding Fume Generated by Apprentice Welders

    PubMed Central

    Graczyk, Halshka; Lewinski, Nastassja; Zhao, Jiayuan; Concha-Lozano, Nicolas; Riediker, Michael

    2016-01-01

    Tungsten inert gas welding (TIG) represents one of the most widely used metal joining processes in industry. Its propensity to generate a greater portion of welding fume particles at the nanoscale poses a potential occupational health hazard for workers. However, current literature lacks comprehensive characterization of TIG welding fume particles. Even less is known about welding fumes generated by welding apprentices with little experience in welding. We characterized TIG welding fume generated by apprentice welders (N = 20) in a ventilated exposure cabin. Exposure assessment was conducted for each apprentice welder at the breathing zone (BZ) inside of the welding helmet and at a near-field (NF) location, 60cm away from the welding task. We characterized particulate matter (PM4), particle number concentration and particle size, particle morphology, chemical composition, reactive oxygen species (ROS) production potential, and gaseous components. The mean particle number concentration at the BZ was 1.69E+06 particles cm−3, with a mean geometric mean diameter of 45nm. On average across all subjects, 92% of the particle counts at the BZ were below 100nm. We observed elevated concentrations of tungsten, which was most likely due to electrode consumption. Mean ROS production potential of TIG welding fumes at the BZ exceeded average concentrations previously found in traffic-polluted air. Furthermore, ROS production potential was significantly higher for apprentices that burned their metal during their welding task. We recommend that future exposure assessments take into consideration welding performance as a potential exposure modifier for apprentice welders or welders with minimal training. PMID:26464505

  20. Centrifugal bubble O{sub 2} ({sup 1{Delta}}) gas generator with a total pressure of 100 Torr

    SciTech Connect

    Zagidulin, M V; Nikolaev, V D; Svistun, M I; Khvatov, N A

    2008-08-31

    A centrifugal bubbling singlet-oxygen gas generator is developed in which chlorine with helium are injected into the rotating layer of the alkali solution of hydrogen peroxide through cylindrical nozzles directed at an angle of 30{sup 0} to the bubbler surface. The concentrations of water vapour and O{sub 2} ({sup 1{Delta}}) and the gas temperature were determined by using the multichannel recording of the emission bands of oxygen at 634, 703, 762 and 1268 nm. For the chlorine and helium flow rates of 60 and 90 mmol s{sup -1}, respectively, the specific chlorine load of 3.2 mmol cm{sup -2}, a total pressure of 100 Torr in the working region of the gas generator and the oxygen partial pressure of 36 Torr, the chlorine utilisation was 90% and the content of O{sub 2} ({sup 1{Delta}}) was {approx}60%. For the ratio of the flow rates of chlorine and the alkali solution of hydrogen peroxide equal to 1 mol L{sup -1}, the water vapour content was {approx}25%. The chemical efficiency of the oxygen-iodine laser with this gas generator achieved 23% for the specific power of 12.7 W cm per 1 cm{sup 3} s{sup -1} per pass of the solution through the gas generator. (laser applications and other topics in quantum electronics)

  1. New concept of power generation analysis for chemical gas turbine in thermodynamic process with heat sources or cooling devices

    SciTech Connect

    Yokogawa, M.; Taniguchi, H.; Yang, W.J.; Nakahara, T.; Arai, N.

    1998-07-01

    Many years ago, a thermodynamic process of power generation was developed for gas turbines, supported by adiabatic expansion and compression. Recently, the possible inlet temperature of gas turbines has increased to 1,500 C, so its blades on the high temperature side have to be cooled by some fluid. If the authors use the actual adiabatic expansion, it is necessary to check the fluid-dynamic friction caused by fluid flow between the blades. In this case, the gas turbine blades have a cooling effect and frictional heat-generating effect, as well. If the authors introduce a new concept, the chemical gas turbine, which creates a reheating effect by heat sources in the expansion process, the outlet temperature of the gas turbine will be increased by this continuous reheating effect. Therefore, when they estimate the performance of a chemical gas turbine, these cooling, frictional and reheating effects have to be checked by theoretical and experimental procedures. The authors here analyze the thermodynamic process with heat sources or cooling devices to illustrate their theoretical approach to estimating these effects. In this study, the definition of the heat-exchange rate is introduced to analyze each heating or cooling process. If the authors introduce this heat-exchange rate into their analysis of the thermodynamic process, it is possible to differentiate between adiabatic, cooling and heating processes in gas turbines and other machines.

  2. A literature review of radiolytic gas generation as a result of the decomposition of sodium nitrate wastes

    SciTech Connect

    Kasten, J.L.

    1991-01-01

    The objective of this literature review is to determine expected chemical reactions and the gas generation associated with radiolytic decomposition of radioactive sodium nitrate wastes such as the wastes stored in the Melton Valley Storage Tanks (MVST) at Oak Ridge National Laboratory (ORNL). The literature survey summarizes expected chemical reactions and identifies the gases expected to be generated as a result of the radiolytic decomposition. The literature survey also identifies G values, which are the expression for radiation chemical yields as molecules of gas formed per 100 eV of absorbed energy, obtained from experimental studies of the radiolytic decomposition of water and sodium nitrate. 2 tabs., 32 refs.

  3. In Situ Analysis of Gas Generation in Lithium-Ion Batteries with Different Carbonate-Based Electrolytes.

    PubMed

    Teng, Xin; Zhan, Chun; Bai, Ying; Ma, Lu; Liu, Qi; Wu, Chuan; Wu, Feng; Yang, Yusheng; Lu, Jun; Amine, Khalil

    2015-10-21

    Gas generation in lithium-ion batteries is one of the critical issues limiting their safety performance and lifetime. In this work, a set of 900 mAh pouch cells were applied to systematically compare the composition of gases generated from a serial of carbonate-based composite electrolytes, using a self-designed gas analyzing system. Among electrolytes used in this work, the composite γ-butyrolactone/ethyl methyl carbonate (GBL/EMC) exhibited remarkably less gassing because of the electrochemical stability of the GBL, which makes it a promising electrolyte for battery with advanced safety and lifetime. PMID:26417916

  4. Addressing challenges of training a new generation of clinician-innovators through an interdisciplinary medical technology design program: Bench-to-Bedside.

    PubMed

    Loftus, Patrick D; Elder, Craig T; D'Ambrosio, Troy; Langell, John T

    2015-01-01

    Graduate medical education has traditionally focused on training future physicians to be outstanding clinicians with basic and clinical science research skills. This focus has resulted in substantial knowledge gains, but a modest return on investment based on direct improvements in clinical care. In today's shifting healthcare landscape, a number of important challenges must be overcome to not only improve the delivery of healthcare, but to prepare future physicians to think outside the box, focus on and create healthcare innovations, and navigate the complex legal, business and regulatory hurdles of bringing innovation to the bedside. We created an interdisciplinary and experiential medical technology design competition to address these challenges and train medical students interested in moving new and innovative clinical solutions to the forefront of medicine. Medical students were partnered with business, law, design and engineering students to form interdisciplinary teams focused on developing solutions to unmet clinical needs. Over the course of six months teams were provided access to clinical and industry mentors, $500 prototyping funds, development facilities, and non-mandatory didactic lectures in ideation, design, intellectual property, FDA regulatory requirements, prototyping, market analysis, business plan development and capital acquisition. After four years of implementation, the program has supported 396 participants, seen the development of 91 novel medical devices, and launched the formation of 24 new companies. From our perspective, medical education programs that develop innovation training programs and shift incentives from purely traditional basic and clinical science research to also include high-risk innovation will see increased student engagement in improving healthcare delivery and an increase in the quality and quantity of innovative solutions to medical problems being brought to market. PMID:25984273

  5. Modeling of gas generation from the Alam El-Bueib formation in the Shoushan Basin, northern Western Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Shalaby, Mohamed Ragab; Hakimi, Mohammed Hail; Abdullah, Wan Hasiah

    2013-01-01

    The Shoushan Basin is an important hydrocarbon province in the northern Western Desert, Egypt, but the burial/thermal histories for most of the source rocks in the basin have not been assigned yet. In this study, subsurface samples from selected wells were collected to characterize the source rocks of Alam El-Bueib Formation and to study thermal history in the Shoushan Basin. The Lower Cretaceous Alam El-Bueib Formation is widespread in the Shoushan Basin, which is composed mainly of shales and sandstones with minor carbonate rocks deposited in a marine environment. The gas generative potential of the Lower Cretaceous Alam El-Bueib Formation in the Shoushan Basin was evaluated by Rock-Eval pyrolysis. Most samples contain sufficient type III organic matter to be considered gas prone. Vitrinite reflectance was measured at eight stratigraphic levels (Jurassic-Cretaceous). Vitrinite reflectance profiles show a general increase of vitrinite reflectance with depth. Vitrinite reflectance values of Alam El-Bueib Formation range between 0.70 and 0.87 VRr %, indicating a thermal maturity level sufficient for hydrocarbon generation. Thermal maturity and burial histories models predict that the Alam El-Bueib source rock entered the mid-mature stage for hydrocarbon generation in the Tertiary. These models indicate that the onset of gas generation from the Alam El-Bueib source rock began in the Paleocene (60 Ma), and the maximum volume of gas generation occurred during the Pliocene (3-2 Ma).

  6. Burial History, Thermal Maturity, and Oil and Gas Generation History of Source Rocks in the Bighorn Basin, Wyoming and Montana

    USGS Publications Warehouse

    Roberts, Laura N.R.; Finn, Thomas M.; Lewan, Michael D.; Kirschbaum, Mark A.

    2008-01-01

    Burial history, thermal maturity, and timing of oil and gas generation were modeled for seven key source-rock units at eight well locations throughout the Bighorn Basin in Wyoming and Montana. Also modeled was the timing of cracking to gas of Phosphoria Formation-sourced oil in the Permian Park City Formation reservoirs at two well locations. Within the basin boundary, the Phosphoria is thin and only locally rich in organic carbon; it is thought that the Phosphoria oil produced from Park City and other reservoirs migrated from the Idaho-Wyoming thrust belt. Other petroleum source rocks include the Cretaceous Thermopolis Shale, Mowry Shale, Frontier Formation, Cody Shale, Mesaverde and Meeteetse Formations, and the Tertiary (Paleocene) Fort Union Formation. Locations (wells) selected for burial history reconstructions include three in the deepest parts of the Bighorn Basin (Emblem Bench, Red Point/Husky, and Sellers Draw), three at intermediate depths (Amoco BN 1, Santa Fe Tatman, and McCulloch Peak), and two at relatively shallow locations (Dobie Creek and Doctor Ditch). The thermal maturity of source rocks is greatest in the deep central part of the basin and decreases to the south, east, and north toward the basin margins. The Thermopolis and Mowry Shales are predominantly gas-prone source rocks, containing a mix of Type-III and Type-II kerogens. The Frontier, Cody, Mesaverde, Meeteetse, and Fort Union Formations are gas-prone source rocks containing Type-III kerogen. Modeling results indicate that in the deepest areas, (1) the onset of petroleum generation from Cretaceous rocks occurred from early Paleocene through early Eocene time, (2) peak petroleum generation from Cretaceous rocks occurred during Eocene time, and (3) onset of gas generation from the Fort Union Formation occurred during early Eocene time and peak generation occurred from late Eocene to early Miocene time. Only in the deepest part of the basin did the oil generated from the Thermopolis and

  7. Assessment of the impact of the next generation solvent on DWPF melter off-gas flammability

    SciTech Connect

    Daniel, W. E.

    2013-02-13

    An assessment has been made to evaluate the impact on the DWPF melter off-gas flammability of replacing the current solvent used in the Modular Caustic-Side Solvent Extraction Process Unit (MCU) process with the Next Generation Solvent (NGS-MCU) and blended solvent. The results of this study showed that the concentrations of nonvolatile carbon and hydrogen of the current solvent in the Slurry Mix Evaporator (SME) product would both be about 29% higher than their counterparts of the NGS-MCU and blended solvent in the absence of guanidine partitioning. When 6 ppm of guanidine (TiDG) was added to the effluent transfer to DWPF to simulate partitioning for the NGS-MCU and blended solvent cases and the concentration of Isopar{reg_sign} L in the effluent transfer was controlled below 87 ppm, the concentrations of nonvolatile carbon and hydrogen of the NGS-MCU and blended solvent were still about 12% and 4% lower, respectively, than those of the current solvent. It is, therefore, concluded that as long as the volume of MCU effluent transfer to DWPF is limited to 15,000 gallons per Sludge Receipt and Adjustment Tank (SRAT)/SME cycle and the concentration of Isopar{reg_sign} L in the effluent transfer is controlled below 87 ppm, using the current solvent assumption of 105 ppm Isopar{reg_sign} L or 150 ppm solvent in lieu of NGS-MCU or blended solvent in the DWPF melter off-gas flammability assessment is conservative for up to an additional 6 ppm of TiDG in the effluent due to guanidine partitioning. This report documents the calculations performed to reach this conclusion.

  8. Microbial gas generation under expected Waste Isolation Pilot Plant repository conditions

    SciTech Connect

    Francis, A.J.; Gillow, J.B.; Giles, M.R.

    1997-03-01

    Gas generation from the microbial degradation of the organic constituents of transuranic waste under conditions expected at the Waste Isolation Pilot Plant (WIPP) repository was investigated at Brookhaven National Laboratory. The biodegradation of mixed cellulosics (various types of paper) and electron-beam irradiated plastic and rubber materials (polyethylene, polyvinylchloride, neoprene, hypalon, and leaded hypalon) was examined. The rate of gas production from cellulose biodegradation in inundated samples incubated for 1,228 days at 30 C was biphasic, with an initial rapid rate up to approximately 600 days incubation, followed by a slower rate. The rate of total gas production in anaerobic samples containing mixed inoculum was as follows: 0.002 mL/g cellulose/day without nutrients; 0.004 mL/g cellulose/day with nutrients; and 0.01 mL/g cellulose/day in the presence of excess nitrate. Carbon dioxide production proceeded at a rate of 0.009 {micro}mol/g cellulose/day in anaerobic samples without nutrients, 0.05 {micro}mol/g cellulose/day in the presence of nutrients, and 0.2 {micro}mol/g cellulose/day with excess nitrate. Adding nutrients and excess nitrate stimulated denitrification, as evidenced by the accumulation of N{sub 2}O in the headspace (200 {micro}mol/g cellulose). The addition of the potential backfill bentonite increased the rate of CO{sub 2} production to 0.3 {micro}mol/g cellulose/day in anaerobic samples with excess nitrate. Analysis of the solution showed that lactic, acetic, propionic, butyric, and valeric acids were produced due to cellulose degradation. Samples incubated under anaerobic humid conditions for 415 days produced CO{sub 2} at a rate of 0.2 {micro}mol/g cellulose/day in the absence of nutrients, and 1 {micro}mol/g cellulose/day in the presence of bentonite and nutrients. There was no evidence of biodegradation of electron-beam irradiated plastic and rubber.

  9. Comparison of Gross Greenhouse Gas Fluxes from Hydroelectric Reservoirs in Brazil with Thermopower Generation

    NASA Astrophysics Data System (ADS)

    Rogerio, J. P.; Dos Santos, M. A.; Matvienko, B.; dos Santos, E.; Rocha, C. H.; Sikar, E.; Junior, A. M.

    2013-05-01

    Widespread interest in human impacts on the Earth has prompted much questioning in fields of concern to the general public. One of these issues is the extent of the impacts on the environment caused by hydro-based power generation, once viewed as a clean energy source. From the early 1990s onwards, papers and studies have been challenging this assumption through claims that hydroelectric dams also emit greenhouse gases, generated by the decomposition of biomass flooded by filling these reservoirs. Like as other freshwater bodies, hydroelectric reservoirs produce gases underwater by biology decomposition of organic matter. Some of these biogenic gases are effective in terms of Global Warming. The decomposition is mainly due by anaerobically regime, emitting methane (CH4), nitrogen (N2) and carbon dioxide (CO2). This paper compare results obtained from gross greenhouse fluxes in Brazilian hydropower reservoirs with thermo power plants using different types of fuels and technology. Measurements were carried in the Manso, Serra da Mesa, Corumbá, Itumbiara, Estreito, Furnas and Peixoto reservoirs, located in Cerrado biome and in Funil reservoir located at Atlantic forest biome with well defined climatologically regimes. Fluxes of carbon dioxide and methane in each of the reservoirs selected, whether through bubbles and/or diffusive exchange between water and atmosphere, were assessed by sampling. The intensity of emissions has a great variability and some environmental factors could be responsible for these variations. Factors that influence the emissions could be the water and air temperature, depth, wind velocity, sunlight, physical and chemical parameters of water, the composition of underwater biomass and the operational regime of the reservoir. Based in this calculations is possible to conclude that the large amount of hydro-power studied is better than thermopower source in terms of atmospheric greenhouse emissions. The comparisons between the reservoirs studied

  10. Autonomous portable pulsed-periodical generator of high-power radiofrequency-pulses based on gas discharge with hollow cathode

    NASA Astrophysics Data System (ADS)

    Bulychev, Sergey V.; Dubinov, Alexander E.; L'vov, Igor L.; Popolev, Vyacheslav L.; Sadovoy, Sergey A.; Sadchikov, Eugeny A.; Selemir, Victor D.; Valiulina, Valeria K.; Vyalykh, Dmitry V.; Zhdanov, Victor S.

    2016-05-01

    Portable autonomous generator of high-power RF-pulses based on the gas discharge with hollow cathode has been designed, fabricated, and tested. Input and output characteristics are the following: discharge current amplitude is 800 A, duration of generated RF-pulses is 350 ns, carrier frequency is ˜90 MHz, power in RF-pulse is 0.5 MW, pulse repetition rate is 0.5 kHz, and device efficiency is ˜25%.

  11. Autonomous portable pulsed-periodical generator of high-power radiofrequency-pulses based on gas discharge with hollow cathode.

    PubMed

    Bulychev, Sergey V; Dubinov, Alexander E; L'vov, Igor L; Popolev, Vyacheslav L; Sadovoy, Sergey A; Sadchikov, Eugeny A; Selemir, Victor D; Valiulina, Valeria K; Vyalykh, Dmitry V; Zhdanov, Victor S

    2016-05-01

    Portable autonomous generator of high-power RF-pulses based on the gas discharge with hollow cathode has been designed, fabricated, and tested. Input and output characteristics are the following: discharge current amplitude is 800 A, duration of generated RF-pulses is 350 ns, carrier frequency is ∼90 MHz, power in RF-pulse is 0.5 MW, pulse repetition rate is 0.5 kHz, and device efficiency is ∼25%. PMID:27250451

  12. Trace Gas Measurements on Mars and Earth using Optical Parametric Generation

    NASA Astrophysics Data System (ADS)

    Numata, K.; Riris, H.; Li, S.; Sun, X.; Abshire, J. B.

    2010-12-01

    Trace gases and their isotopic ratios in planetary atmospheres offer important but subtle clues as to the origins of a planet's atmosphere, hydrology, geology, and potential for biology. An orbiting laser remote sensing instrument is capable of measuring trace gases on a global scale with unprecedented accuracy, and higher spatial resolution that can be obtained by passive instruments. We have developed an active sensing instrument for the remote measurement of trace gases in planetary atmospheres (including Earth). The technique uses widely tunable, seeded optical parametric generation (OPG) to measure methane, CO2, water vapor, and other trace gases in the near and mid-infrared spectral regions. Methane is a strong greenhouse gas on Earth and it is also a potential biogenic marker on Mars and other planets. Methane in the Earth’s atmosphere survives for a shorter time than CO2 but its impact on climate change can be larger than CO2. Methane levels have remained relatively constant over the last decade around 1.78 parts per million (ppm) but recent observations indicate that methane levels may be on the rise. Increasing methane concentrations may trigger a positive feedback loop and a subsequent “runaway” greenhouse effect, where increasing temperatures result in increasing methane levels. The NRC Decadal Survey recognized the importance of global observations of greenhouse gases and called for simultaneous CH4, CO, and CO2 measurements but also underlined the technological limitations for these observations. For Mars, methane measurements are of great interest because of its potential as a strong biogenic marker. A remote sensing instrument that can measure day and night over all seasons and latitudes can identify and localize sources of biogenic gas plumes produced by subsurface chemistry or biology, and aid in the search for extra-terrestrial life. It can identify the dynamics of methane generation over time and latitude and identify future lander mission

  13. Trace Gas Measurements on Mars and Earth Using Optical Parametric Generation

    NASA Technical Reports Server (NTRS)

    Numata, Kenji; Haris, Riris; Li, Steve; Sun, Xiaoli; Abshire, James Brice

    2010-01-01

    Trace gases and their isotopic ratios in planetary atmospheres offer important but subtle clues as to the origins of a planet's atmosphere, hydrology, geology, and potential for biology. An orbiting laser remote sensing instrument is capable of measuring trace gases on a global scale with unprecedented accuracy, and higher spatial resolution that can be obtained by passive instruments. We have developed an active sensing instrument for the remote measurement of trace gases in planetary atmospheres (including Earth). The technique uses widely tunable, seeded optical parametric generation (OPG) to measure methane, CO2, water vapor, and other trace gases in the near and mid-infrared spectral regions. Methane is a strong greenhouse gas on Earth and it is also a potential biogenic marker on Mars and other planets. Methane in the Earth's atmosphere survives for a shorter time than CO2 but its impact on climate change can be larger than CO2. Methane levels have remained relatively constant over the last decade around 1.78 parts per million (ppm) but recent observations indicate that methane levels may be on the rise. Increasing methane concentrations may trigger a positive feedback loop and a subsequent runaway greenhouse effect, where increasing temperatures result in increasing methane levels. The NRC Decadal Survey recognized the importance of global observations of greenhouse gases and called for simultaneous CH4, CO, and CO2 measurements but also underlined the technological limitations for these observations. For Mars, methane measurements are of great interest because of its potential as a strong biogenic marker. A remote sensing instrument that can measure day and night over all seasons and latitudes can identify and localize sources of biogenic gas plumes produced by subsurface chemistry or biology, and aid in the search for extra-terrestrial life. It can identify the dynamics of methane generation over time and latitude and identify future lander mission sites

  14. Generation of gas-phase zirconium fluoroanions by electrospray of an ionic liquid

    SciTech Connect

    Gary S. Groenewold; James E. Delmore; Michael T. Benson; Tetsuya Tsuda; Rika Hagiwara

    2014-06-01

    RATIONALE: When measuring extremely wide isotope ratios (= 1 x 109) accelerator mass spectrometry (AMS) is the instrument of choice, however it requires an anion for injection into the tandem accelerator. Since many elements do not have positive electronegativities they do not form stable negative atomic ions, and hence are not compatible for isotope ratio measurement using AMS. Thus new approaches for forming anions are sought; fluoroanions are particularly attractive because fluorine is monoisotopic, and thus will not have overlapping isobars with the isotope of interest. METHODS: An approach is described for making zirconium fluoroanions using the fluorinating ionic liquid (IL) 1-ethyl-3-methylimidazolium fluorohydrogenate, which was used to generate abundant [ZrF5-] using electrospray ionization. The IL was dissolved in acetonitrile, combined with a dilute solution of either Zr4+ or ZrO2+, and then electrosprayed. Mass analysis and collision induced dissociation were conducted using a time-of-flight mass spectrometer. Cluster structures were predicted using density functional theory calculations. RESULTS: The fluorohydrogenate IL solutions generated abundant [ZrF5-] starting from solutions of both Zr4+ and ZrO2+. The mass spectra also contained IL-bearing cluster ions, whose compositions indicated the presence of [ZrF6]2- in solution, a conclusion supported by the structural calculations. Rinsing out the zirconium-IL solution with acetonitrile decreased the IL clusters, but enhanced [ZrF5]-, which was sorbed by the polymeric electrospray supply capillary, and then released upon rinsing. This reduced the ion background in the mass spectrum. CONCLUSIONS: The fluorohydrogenate-IL solutions are a facile way to form zirconium fluoroanions in the gas phase using electrospray. The approach has potential as a source of fluoroanions for injection into an AMS, which would enable high-sensitivity measurement of minor zirconium isotopes, and benefits from the absence of

  15. Comparison between landfill gas and waste incineration for power generation in Astana, Kazakhstan.

    PubMed

    Inglezakis, Vassilis J; Rojas-Solórzano, Luis; Kim, Jong; Aitbekova, Aisulu; Ismailova, Aizada

    2015-05-01

    The city of Astana, the capital of Kazakhstan, which has a population of 804,474, and has been experiencing rapid growth over the last 15 years, generates approximately 1.39 kg capita(-1) day(-1) of municipal solid waste (MSW). Nearly 700 tonnes of MSW are collected daily, of which 97% is disposed of at landfills. The newest landfill was built using modern technologies, including a landfill gas (LFG) collection system.The rapid growth of Astana demands more energy on its path to development, and the viability analysis of MSW to generate electricity is imperative. This paper presents a technical-economic pre-feasibility study comparing landfill including LFG utilization and waste incineration (WI) to produce electricity. The performance of LFG with a reciprocating engine and WI with steam turbine power technologies were compared through corresponding greenhouse gases (GHG) reduction, cost of energy production (CEP), benefit-cost ratio (BCR), net present value (NPV) and internal rate of return (IRR) from the analyses. Results demonstrate that in the city of Astana, WI has the potential to reduce more than 200,000 tonnes of GHG per year, while LFG could reduce slightly less than 40,000 tonnes. LFG offers a CEP 5.7% larger than WI, while the latter presents a BCR two times higher than LFG. WI technology analysis depicts a NPV exceeding 280% of the equity, while for LFG, the NPV is less than the equity, which indicates an expected remarkable financial return for the WI technology and a marginal and risky scenario for the LFG technology. Only existing landfill facilities with a LFG collection system in place may turn LFG into a viable project. PMID:25819927

  16. A statistical review of the oxygen data from the gas generation tests supporting the revision of the 9975 SARP

    SciTech Connect

    Edwards, T.B.

    2000-01-20

    The Chemical and Hydrogen Technology Section (CHT) of the Savannah River Technology Center (SRTC) has conducted a series of gas generation tests in support of the revision of the safety analysis report for packaging (SARP) for the 9975 container, developed at the Savannah River Site (SRS). The Packaging and Transportation Group of SRTC is coordinating the revision to this SARP. A Task Technical and Quality Assurance Plan directing this work was issued by CHT in February 1999. Initially, the primary interest in this testing was hydrogen generation. From these ``gas generation tests can be tracked in real-time by measuring the pressure of a sealed container of the materials being studied. Because multiple gas phase reactions are produced in the radiation field of the sample, material pressure measurements do not necessarily define the quantity of H{sub 2} generated. However, the change in total molecules of gas can be calculated using the ideal gas law from the pressure measurement, known container volume and sample temperature. A measurement of the actual headspace gases must be completed to calculate the H{sub 2} generation rate for a particular sample.'' As the results from these tests were reviewed, however, questions arose regarding the oxygen in the headspace gases. Specifically, do the data from some tests indicate that oxygen was generated for those tests? And do the data for other tests indicate that the oxygen was depleted for them? A statistical analysis of the oxygen data derived from these tests is provided in this report to help answer these questions.

  17. Dependence of Ozone Generation on Gas Temperature Distribution in AC Atmospheric Pressure Dielectric Barrier Discharge in Oxygen

    NASA Astrophysics Data System (ADS)

    Takahashi, Go; Akashi, Haruaki

    AC atmospheric pressure multi-filament dielectric barrier discharge in oxygen has been simulated using two dimensional fluid model. In the discharge, three kinds of streamers have been obtained. They are primary streamers, small scale streamers and secondary streamers. The primary streamers are main streamers in the discharge and the small scale streamers are formed after the ceasing of the primary streamers. And the secondary streamers are formed on the trace of the primary streamers. In these streamers, the primary and the small scale streamers are very effective to generate O(3P) oxygen atoms which are precursor of ozone. And the ozone is generated mainly in the vicinity of the dielectrics. In high gas temperature region, ozone generation decreases in general. However, increase of the O(3P) oxygen atom density in high gas temperature region compensates decrease of ozone generation rate coefficient. As a result, amount of ozone generation has not changed. But if the effect of gas temperature was neglected, amount of ozone generation increases 10%.

  18. Potential for generation of natural gas in sediments of the convergent margin of the Aleutian Trench Area

    SciTech Connect

    Kvenvolden, K.A.; von Huene, R.

    1983-01-01

    Sediment being subducted in the eastern part of the convergent margin of the Aleutian Trench has a potential to generate large volumes of natural gas, perhaps as much as 2.8 x 10/sup 6/ m/sup 3/ of methane per km/sup 3/ of sediment, even though the content of organic carbon in the sediment is very low, averaging about 0.4%. This high potential for gas generation results primarily from the enormous volume of sediment undergoing subduction. Along the eastern Aleutian Arc-Trench system a 3-km thick sheet of sediment is being subducted at a rate of about 60 km per million years. We estimate, based on considerations of the stability requirements for gas hydrates observed as anomalous reflectors in some of our seismic records, and on one measurement in a deep well, that the geothermal gradient in this region is about 30/sup 0/C/km. Such a gradient suggests a temperature regime in which the maximum gas generation in the subducting sediment occurs beneath the upper slope. Thus the sediment of the upper slope, as opposed to that of the shelf and lower slope, could be the most prospective for gas accumulation if suitable reservoirs are present. 40 refs., 11 figs., 3 tabs.

  19. Efficiency of silane gas generation in high-rate silicon etching by narrow-gap microwave hydrogen plasma

    NASA Astrophysics Data System (ADS)

    Ohmi, Hiromasa; Funaki, Takeshi; Kakiuchi, Hiroaki; Yasutake, Kiyoshi

    2016-01-01

    The silicon (Si) etching characteristics and the related efficiency of the etched Si to generate SiH4 gas in narrow-gap high-pressure microwave H2 plasma have been investigated. It was found that cooling of the Si sample is effective to obtain a high etching rate even under high pressure conditions, and the excess temperature increase of both the gas and Si sample can be suppressed even at an input power density of more than 250 W cm-3, probably because of the narrow plasma gap. The local etching depth monotonically increased with increasing H2 pressure and input plasma power, whereas the etching weight decreased with increasing H2 pressure. By simultaneously increasing the H2 pressure and input power, a maximum Si etching rate of 38 μm min-1 was achieved. This is considered to be related to the high H density generated in the narrow-gap microwave plasma at relatively low temperatures. The energy efficiency of Si etching and the utilization efficiency of the etched Si and H2 gas for SiH4 formation are discussed. Lower input power is favorable for high energy efficiency of Si etching. The Si utilization efficiency, which is defined as the molar ratio of generated SiH4 to etched Si, increases with decreasing average gas residence time in the plasma, whereas H2 utilization efficiency is independent of the gas residence time.

  20. Conceptual design for a kerosene fuel-rich gas-generator of a turbopump-fed liquid rocket engine

    NASA Astrophysics Data System (ADS)

    Son, Min; Koo, Jaye; Cho, Won Kook; Lee, Eun Seok

    2012-10-01

    A design method for a kerosene fuel-rich gas-generator of a liquid rocket engine using turbopumps to supply propellant was performed at a conceptual level. The gas-generator creates hot gases, enabling the turbine to operate the turbopumps. A chemical non-equilibrium analysis and a droplet vaporization model were used for the estimation of the burnt gas properties and characteristic chamber length. A premixed counter-flow flame analysis was performed for the prediction of the burnt gas properties, namely the temperature, the specific heat ratio and heat capacity, and the chemical reaction time. To predict the vaporization time, the Spalding model, using a single droplet in convective condition, was used. The minimum residence time in the chamber and the characteristic length were calculated by adding the reaction time and the vaporization time. Using the characteristic length, the design methods for the fuel-rich gas-generator were established. Finally, a parametric study was achieved for the effects of the O/F ratio, mass flow rate, chamber pressure, initial droplet temperature, initial droplet diameter and initial droplet velocity.

  1. Combustion efficiency: Greenhouse gas emission reductions from the power generation sector

    SciTech Connect

    Kane, R.; South, D.W.; Fish, A.L.

    1993-12-31

    Concern for the possibility of an enhanced greenhouse effect and global climate change (GCC) has often been associated with energy use in general, and fossil fuel combustion in particular, because of associated emissions of CO{sub 2} and other greenhouse gases (GHG). Therefore, energy policies play a significant role in determining greenhouse gas emissions. The generation of electricity and power from more efficient fossil energy technologies provides an opportunity to significantly lower GHG emissions, together with other pollutants. The U.S. government oversees a broad-based program to facilitate the development, demonstration, and deployment of these technologies. Advanced fossil technologies offer other benefits as well, in that they permit continued use of widely available fuels such as coal. An international perspective is critical for assessing the role of these fuels, since countries differ in terms of their ability to maximize these benefits. Often, new technologies are considered the domain of industrialized countries. Yet more efficient technologies may have their greatest potential - to concurrently permit the utilization of indigenous fuels and to lower global GHG emissions in developing countries, especially those in the Asia-Pacific region.

  2. Automated Generation of 3D Volcanic Gas Plume Models for Geobrowsers

    NASA Astrophysics Data System (ADS)

    Wright, T. E.; Burton, M.; Pyle, D. M.

    2007-12-01

    A network of five UV spectrometers on Etna automatically gathers column amounts of SO2 during daylight hours. Near-simultaneous scans from adjacent spectrometers, comprising 210 column amounts in total, are then converted to 2D slices showing the spatial distribution of the gas by tomographic reconstruction. The trajectory of the plume is computed using an automatically-submitted query to NOAA's HYSPLIT Trajectory Model. This also provides local estimates of air temperature, which are used to determine the atmospheric stability and therefore the degree to which the plume is dispersed by turbulence. This information is sufficient to construct an animated sequence of models which show how the plume is advected and diffused over time. These models are automatically generated in the Collada Digital Asset Exchange format and combined into a single file which displays the evolution of the plume in Google Earth. These models are useful for visualising and predicting the shape and distribution of the plume for civil defence, to assist field campaigns and as a means of communicating some of the work of volcano observatories to the public. The Simultaneous Algebraic Reconstruction Technique is used to create the 2D slices. This is a well-known method, based on iteratively updating a forward model (from 2D distribution to column amounts). Because it is based on a forward model, it also provides a simple way to quantify errors.

  3. Dissolution of Uranium Metal Without Hydride Formation or Hydrogen Gas Generation

    SciTech Connect

    Soderquist, Chuck Z.; Oliver, Brian M.; McNamara, Bruce K.

    2008-09-01

    This study shows that metallic uranium will cleanly dissolve in carbonate-peroxide solution without generation of hydrogen gas or uranium hydride. Metallic uranium shot, 0.5 to 1 mm diameter, were reacted with ammonium carbonate - hydrogen peroxide solution ranging in concentration from 0.13M to 1.0M carbonate and 0.50M to 2.0M peroxide. The uranium beads were weighed before and after reacting with the etch solution, and from the weights of the beads, their diameters were calculated, before and after the etch. The etch rate on the beads was then calculated from the reduction in bead diameter, and independently by uranium analysis of the solution. The calculated etch rate ranged from about 4 x 10-4 to 8 x 10-4 cm per hour, dependent primarily on the peroxide concentration. A hydrogen analysis of the etched beads showed that no detectable hydrogen was introduced into the uranium metal by the etching process.

  4. Co-generated fast pyrolysis biochar mitigates green-house gas emissions and increases carbon sequestration in temperate soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar (BC) is a product of thermochemical conversion of biomass via pyrolysis, together with gas (syngas), liquid (bio-oil), and heat. Fast pyrolysis is a promising process for bio-oil generation, which leaves 10-30% of the original biomass as char. When applied to soils, BC may increase soil C s...

  5. 76 FR 36914 - Astoria Generating Company, L.P., NRG Power Marketing LLC, Arthur Kill Power LLC, Astoria Gas...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-23

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Astoria Generating Company, L.P., NRG Power Marketing LLC, Arthur Kill Power LLC, Astoria Gas Turbine Power LLC, Dunkirk Power LLC, Huntley Power LLC, Oswego Harbor Power LLC, TC Ravenswood, LLC, v. New York...

  6. 76 FR 36910 - Astoria Generating Company, L.P., NRG Power Marketing LLC, Arthur Kill Power LLC, Astoria Gas...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-23

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Astoria Generating Company, L.P., NRG Power Marketing LLC, Arthur Kill Power LLC, Astoria Gas Turbine Power LLC, Dunkirk Power LLC, Huntley Power LLC, Oswego Harbor Power LLC, TC Ravenswood, LLC. v. New York...

  7. 76 FR 34692 - Astoria Generating Company, L.P., NRG Power Marketing LLC, Arthur Kill Power LLC, Astoria Gas...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-14

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Astoria Generating Company, L.P., NRG Power Marketing LLC, Arthur Kill Power LLC, Astoria Gas Turbine Power LLC, Dunkirk Power LLC, Huntley Power LLC, Oswego Harbor Power LLC, TC Ravenswood, LLC; v. New York...

  8. Improving the efficiency of high harmonic generation (HHG) by Ne-admixing into a pure Ar gas medium

    NASA Astrophysics Data System (ADS)

    Seo, Hyun Ook; Arion, Tiberiu; Roth, Friedrich; Ramm, Daniel; Lupulescu, Cosmin; Eberhardt, Wolfgang

    2016-04-01

    Laser-based higher-order harmonic generation has been investigated extensively in the past two decades. The current manuscript deals with the high harmonic generation (HHG) outputs from a gas-filled waveguide when using mixtures of two rare gases (Ar and Ne) as nonlinear media. We find that the efficiency of the HHG process can be optimized by changing the pressure or alternatively the mixing ratio of the two gases. This is attributed to the fact that both of these parameters have an effect on the phase-matching in the waveguide. These observations are especially useful when phase matching in a gas jet is concerned, where the absolute local pressure of the gas media cannot be controlled as readily as in a capillary-based HHG setup.

  9. Oil- and gas-generating properties of the Devonian carbonate-terrigenous sediments (north sector of the Timan-Pechora oil- and gas-bearing basin)

    SciTech Connect

    Korchagina, Yu.I.; Fadeeva, N.P.

    1995-05-01

    This paper discusses the oil- and gas-generating properties and potential of Devonian age carbonate rocks in the Timan-Pechora Basin, U.S.S.R. A comprehensive geochemical investigation using rock pyrolysis and other tests of 490 rock samples has been carried out. Geochemical information recorded during this study has provided the possibility for identifying an initial genetic type of organic matter and its role in hydrocarbon generation. The potential productivity of Devonian rocks in the region may be estimated on the basis of their genetic history.

  10. Safety considerations in testing a fuel-rich aeropropulsion gas generator

    NASA Technical Reports Server (NTRS)

    Rollbuhler, R. James; Hulligan, David D.

    1991-01-01

    A catalyst containing reactor is being tested using a fuel-rich mixture of Jet A fuel and hot input air. The reactor product is a gaseous fuel that can be utilized in aeropropulsion gas turbine engines. Because the catalyst material is susceptible to damage from high temperature conditions, fuel-rich operating conditions are attained by introducing the fuel first into an inert gas stream in the reactor and then displacing the inert gas with reaction air. Once a desired fuel-to-air ratio is attained, only limited time is allowed for a catalyst induced reaction to occur; otherwise the inert gas is substituted for the air and the fuel flow is terminated. Because there presently is not a gas turbine combustor in which to burn the reactor product gas, the gas is combusted at the outlet of the test facility flare stack. This technique in operations has worked successfully in over 200 tests.

  11. How to quantify uncertainty and variability in life cycle assessment: the case of greenhouse gas emissions of gas power generation in the US

    NASA Astrophysics Data System (ADS)

    Hauck, M.; Steinmann, Z. J. N.; Laurenzi, I. J.; Karuppiah, R.; Huijbregts, M. A. J.

    2014-07-01

    This study quantified the contributions of uncertainty and variability to the range of life-cycle greenhouse gas (LCGHG) emissions associated with conventional gas-fired electricity generation in the US. Whereas uncertainty is defined as lack of knowledge and can potentially be reduced by additional research, variability is an inherent characteristic of supply chains and cannot be reduced without physically modifying the system. The life-cycle included four stages: production, processing, transmission and power generation, and utilized a functional unit of 1 kWh of electricity generated at plant. Technological variability requires analyses of life cycles of individual power plants, e.g. combined cycle plants or boilers. Parameter uncertainty was modeled via Monte Carlo simulation. Our approach reveals that technological differences are the predominant cause for the range of LCGHG emissions associated with gas power, primarily due to variability in plant efficiencies. Uncertainties in model parameters played a minor role for 100 year time horizon. Variability in LCGHG emissions was a factor of 1.4 for combined cycle plants, and a factor of 1.3 for simple cycle plants (95% CI, 100 year horizon). The results can be used to assist decision-makers in assessing factors that contribute to LCGHG emissions despite uncertainties in parameters employed to estimate those emissions.

  12. Atmospheric pressure glow discharge generated in nitrogen-methane gas mixture: PTR-MS analyzes of the exhaust gas

    NASA Astrophysics Data System (ADS)

    Torokova, Lucie; Mazankova, Vera; Krcma, Frantisek; Mason, Nigel J.; Matejcik, Stefan

    2015-07-01

    This paper reports the results of an extensive study of with the in situ mass spectrometry analysis of gaseous phase species produced by an atmospheric plasma glow discharge in N2-CH4 gas mixtures (with methane concentrations ranging from 1% to 4%). The products are studied using proton-transfer-reaction mass spectrometry (PTR-MS). HCN and CH3CN are identified as the main gaseous products. Hydrazine, methanimine, methyldiazene, ethylamine, cyclohexadiene, pyrazineacetylene, ethylene, propyne and propene are identified as minor compounds. All the detected compounds and their relative abundances are determined with respect to the experimental conditions (gas composition and applied power). The same molecules were observed by the Cassini-Huygens probe in Titan's atmosphere (which has same N2-CH4 gas mixtures). Such, experiments show that the formation of such complex organics in atmospheres containing C, N and H, like that of Titan, could be a source of prebiotic molecules. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  13. Landfill gas cleanup for carbonate fuel cell power generation. Final report

    SciTech Connect

    Steinfield, G.; Sanderson, R.

    1998-02-01

    Landfill gas represents a significant fuel resource both in the US and worldwide. The emissions of landfill gas from existing landfills has become an environmental liability contributing to global warming and causing odor problems. Landfill gas has been used to fuel reciprocating engines and gas turbines, and may also be used to fuel carbonate fuel cells. Carbonate fuel cells have high conversion efficiencies and use the carbon dioxide present in landfill gas as an oxidant. There are, however, a number of trace contaminants in landfill gas that contain chlorine and sulfur which are deleterious to fuel cell operation. Long-term economical operation of fuel cells fueled with landfill gas will, therefore, require cleanup of the gas to remove these contaminants. The overall objective of the work reported here was to evaluate the extent to which conventional contaminant removal processes could be combined to economically reduce contaminant levels to the specifications for carbonate fuel cells. A pilot plant cleaned approximately 970,000 scf of gas over 1,000 hours of operation. The testing showed that the process could achieve the following polished gas concentrations: less than 80 ppbv hydrogen sulfide; less than 1 ppmv (the detection limit) organic sulfur; less than 300 ppbv hydrogen chloride; less than 20--80 ppbv of any individual chlorinated hydrocarbon; and 1.5 ppm sulfur dioxide.

  14. Evaluation of Gas-Cooled Pressurized Phosphoric Acid Fuel Cells for Electric Utility Power Generation

    NASA Technical Reports Server (NTRS)

    Faroque, M.

    1983-01-01

    Gas cooling is a more reliable, less expensive and a more simple alternative to conventional liquid cooling for heat removal from the phosphoric acid fuel cell (PAFC). The feasibility of gas-cooling was already demonstrated in atmospheric pressure stacks. Theoretical and experimental investigations of gas-cooling for pressurized PAFC are presented. Two approaches to gas cooling, Distributed Gas-Cooling (DIGAS) and Separated Gas-Cooling (SGC) were considered, and a theoretical comparison on the basis of cell performance indicated SGC to be superior to DIGAS. The feasibility of SGC was experimentally demonstrated by operating a 45-cell stack for 700 hours at pressure, and determining thermal response and the effect of other related parameters.

  15. Awards and Addresses Summary

    PubMed Central

    2008-01-01

    Each year at the annual ASHG meeting, addresses are given in honor of the society and a number of award winners. A summary of each of these addresses is given below. On the next pages, we have printed the Presidential Address and the addresses for the William Allan Award. The other addresses, accompanied by pictures of the speakers, can be found at www.ashg.org.

  16. Generation, Detection and characterization of Gas-Phase Transition Metal containing Molecules

    SciTech Connect

    Steimle, Timothy

    2015-12-15

    The objective of this project was to generate, detect, and characterize small, gas-phase, metal containing molecules. In addition to being relevant to high temperature chemical environments (e.g. plasmas and combustion), gas-phase experiments on metal containing molecules serve as the most direct link to a molecular-level theoretical model for catalysis. Catalysis (i.e. the addition of a small about of recoverable material to control the rate and direction of a chemical reaction) is critical to the petroleum and pharmaceutical industries as well as environmental remediation. Currently, the majority of catalytic materials are based on very expensive metals such as platinum (Pt), palladium (Pd), iridium (Ir,) rhenium (Re), and rhodium (Rh). For example, the catalyst used for converting linear hydrocarbon molecules (e.g. hexane) to cyclic molecules (e.g. cyclohexane) is a mixture of Pt and Re suspended on alumina. It enables straight chain alkanes to be converted into branched-chain alkanes, cyclohexanes and aromatic hydrocarbons which are used, amongst other things, to enhance the octane number of petrol. A second example is the heterogeneous catalysis used in automobile exhaust systems to: a) decrease nitrogen oxide; b) reduce carbon monoxide; and c) oxidize unburned hydrocarbons. The exhaust is vented through a high-surface area chamber lined with Pt, Pd, and Rh. For example, the carbon monoxide is catalytically converted to carbon dioxide by reaction with oxygen. The research results from this work have been published in readily accessible journals1-28. The ground and excited electronic state properties of small metal containing molecules that we determine were: a) electronic state distributions and lifetimes, b) vibrational frequencies, c) bond lengths and angles, d) hyperfine interactions, e) permanent electric dipole moments, mel, and f) magnetic dipoles, μm. In general terms, μel, gives insight into the charge distribution and mm into

  17. Long-Implosion-Time Z-pinch Experiments with Deuterium Gas-Puffs on the GIT-12 Generator

    NASA Astrophysics Data System (ADS)

    Klir, D.; Kubes, P.; Rezac, K.; Cikhardt, J.; Kravarik, J.; Shishlov, A.; Labetsky, A.; Fursov, F.; Kokshenev, V.; Kovalchuk, B.; Kurmaev, N.; Ratakhin, N.

    2012-10-01

    Experiments with deuterium triple shell gas-puffs have been carried out on the GIT-12 generator at the IHCE in Tomsk. Outer, middle, and inner nozzle diameters were 160 mm, 80 mm and 30 mm, respectively. The influence of the mass of deuterium shells on neutron emission times, neutron yields and neutron spectra was studied. The linear mass density of deuterium varied between 50 and 270 μg/cm. Gas puffs imploded onto the axis before the peak of a generator current at 700-1100 ns. The first neutron peak occurred during the stagnation. Most of the neutrons were emitted during the second neutron pulse after the development of instabilities. In lower mass gas puffs, neutron energies of up to 4.4 MeV gave the evidence of 1 MeV deuterons. The peak neutron yield from D(d,n)^3He reactions reached 3x10^11 on a current level of 2.5 MA. Secondary DT neutrons were measured by BDS-10000 bubble detectors. An average neutron yield ratio Y>10 MeV/Y2.5 MeV exceeded (6±3)x10-4. Ne-Ne-D2 and Ne-D2-D2 gas puffs produced 3 times lower neutron yields but the first neutron pulse during the stagnation was nearly the same as with D2-D2-D2 gas puffs.

  18. Radcalc for windows benchmark study: A comparison of software results with Rocky Flats hydrogen gas generation data

    SciTech Connect

    MCFADDEN, J.G.

    1999-07-19

    Radcalc for Windows Version 2.01 is a user-friendly software program developed by Waste Management Federal Services, Inc., Northwest Operations for the U.S. Department of Energy (McFadden et al. 1998). It is used for transportation and packaging applications in the shipment of radioactive waste materials. Among its applications are the classification of waste per the US. Department of Transportation regulations, the calculation of decay heat and daughter products, and the calculation of the radiolytic production of hydrogen gas. The Radcalc program has been extensively tested and validated (Green et al. 1995, McFadden et al. 1998) by comparison of each Radcalc algorithm to hand calculations. An opportunity to benchmark Radcalc hydrogen gas generation calculations to experimental data arose when the Rocky Flats Environmental Technology Site (RFETS) Residue Stabilization Program collected hydrogen gas generation data to determine compliance with requirements for shipment of waste in the TRUPACT-II (Schierloh 1998). The residue/waste drums tested at RFETS contain contaminated, solid, inorganic materials in polyethylene bags. The contamination is predominantly due to plutonium and americium isotopes. The information provided by Schierloh (1 998) of RFETS includes decay heat, hydrogen gas generation rates, calculated G{sub eff} values, and waste material type, making the experimental data ideal for benchmarking Radcalc. The following sections discuss the RFETS data and the Radcalc cases modeled with the data. Results are tabulated and also provided graphically.

  19. Gamma irradiation test report of simulated grout specimens for gas generation/liquid advection

    SciTech Connect

    Hinman, C.A.

    1994-10-14

    This report presents the results from an irradiation test performed on four specimens of grout that were fabricated from synthetic Double Shell Slurry Feed (DSSF) liquid waste. The objective was to investigate the radiolytic generation of gases and the potential for advective rejection of waste liquids from the grout matrix and to provide experimental information for the validation of the C-Cubed calculated model. It has been demonstrated that a number of gases can be formed within the grout due to radiolytic decomposition of various chemical components that make up the grout. This observation leads to the conjecture that the potential exists for the rejection of a portion of the 60 vol% free liquid from the grout matrix driven by pressurization by these gases. It was found that, for the specimen geometries used in this test series, and for peak radiation dose accumulation rates on the order of 4 to 60 times of the initial rate expected in the grout vaults (300 Rads/hr), no liquid rejection was observed from 2% to 35% of the target exposure expected in the grout vaults (1E+08 Rads). When the irradiation rate exceeded the projected grout vault dose rate by a factor of 200 a small amount of liquid rejection was observed from one of two specimens that had received 20% more than the goal exposure. Because of the differences in the magnitudes of the relative radiation field strengths between this study and an actual grout vault, it is concluded that the potential for liquid rejection by internal gas pressurization from presently configured grout waste forms is very low for the expected conditions.

  20. Generation IV nuclear energy system initiative. Pin core subassembly designfor the Gas-Cooled Fast Reactor.

    SciTech Connect

    Farmer, M. T.; Hoffman, E. A.; Pfeiffer, P. F.; Therios, I. U.

    2006-07-31

    The Gas-Cooled Fast Reactor (GFR) is one of six systems selected for viability assessment in the Generation IV program. It features a closed nuclear fuel cycle, consisting of a high-temperature helium-cooled fast spectrum reactor, coupled to a direct-cycle helium turbine for electricity production. The GFR combines the advances of fast spectrum systems with those of high-temperature systems. It was clear from the very beginning that GFR design should be driven by the objective to offer a complementary approach to liquid metal cooling. On this basis, CEA and the US DOE decided to collaborate on the pre-conceptual design of a GFR. This reactor design will provide a high level of safety and full recycling of the actinides, and will also be highly proliferation resistant and economically attractive. The status of this collaborative project is that two unit sizes, 600 MWt and 2400 MWt were selected as the focus of the design and safety studies. Researchers studied fuel forms, fuel assembly/element designs, core configurations, primary and balance-of-plant layouts, and safety approaches for both of these unit sizes. Results regarding the feasibility of this GFR design are encouraging. For example, sustainability and non-proliferation goals can be met and the proposed concept has attractive safety features. These features take advantage of the helium in terms of its neutronic quasi-transparency as well as the enhanced Doppler effect in connection with candidate fuel and structural materials. The current design trend is to consider high unit power for the GFR (2400 MWt), an attractive level for the power density (100 MW/m{sup 3}), and the implementation of an innovative plate type fuel or pin type sub-assembly with carbide-based actinide compounds and SiC-based structural materials. Work is still needed to refine the safety approach, to select the main system options, and to more definitively establish economic parameters.

  1. Principles and computer simulations of intercooled-turbocharged gas generator/expander engine

    SciTech Connect

    Jeng, Y.L.

    1991-01-01

    An internal combustion engine is proposed that is based on a patent of Dr. L. S. Wang. This engine utilizes a two-stage adiabatic compression with intercooling to reduce exhaust energy loss, and a reciprocating piston-gasifier to raise the cycle peak temperature. Combustion occurs within piston-gasifier to generate high temperature and pressure gases with no brake net work output. The discharge gas expands in turbocharging turbine to drive the two compressors. Further expansion is performed in the power turbine to produce the engine power output. To study the feasibility of the proposed engine, piston-gasifier is designed and computer code was developed to simulate the engine operations. Processes in various system components are described by several submodels which are integrated in the computer code to predict the engine performance. The piston-gasifier model treats manifolds and cylinders as open systems and combustion is described as a one-zone heat release process. Processes including heat transfer and friction are described in sufficient detail to determine the mass and energy transfers in each manifold and master cylinder. The power turbine is described by the modified Stodola Ellipse while other machineries are described by scaled performance maps. Intercoolers are modeled by a combination of analytical solutions and empirical correlations. The predicted quasi-steady performance characteristics of piston-gasifier are studied. And a reference operating point is chosen to select turbomachineries and to design intercoolers. The system performance is obtained by matching the operations of all components. Covering a wide range of operations, the results of engine simulations show that excellent part load performance is obtained by the reduction of exhaust energy loss. Still liable to refinements, discussions are made, pointing out future directions of further improvement.

  2. Formulation and Performance of Novel Energetic Nanocomposites and Gas Generators Prepared by Sol-Gel Methods

    SciTech Connect

    Clapsaddle, B J; Zhao, L; Prentice, D; Pantoya, M L; Gash, A E; Satcher Jr., J H; Shea, K J; Simpson, R L

    2005-03-24

    In the field of composite energetic materials, properties such as ingredient distribution, particle size, and morphology affect both sensitivity and performance. Since the reaction kinetics of composite energetic materials are typically controlled by the mass transport rates between reactants, one would anticipate new and potentially exceptional performance from energetic nanocomposites. We have developed a new method of making nanostructured energetic materials, specifically explosives, propellants, and pyrotechnics, using sol-gel chemistry. A novel sol-gel approach has proven successful in preparing nanostructured metal oxide materials. By introducing a fuel metal, such as aluminum, into the nanostructured metal oxide matrix, energetic materials based on thermite reactions can be fabricated. Two of the metal oxides are tungsten trioxide and iron(III) oxide, both of which are of interest in the field of energetic materials. Due to the versatility of the preparation method, binary oxidizing phases can also be prepared, thus enabling a potential means of controlling the energetic properties of the subsequent nanocomposites. Furthermore, organic additives can also be easily introduced into the nanocomposites for the production of nanostructured gas generators. The resulting nanoscale distribution of all the ingredients displays energetic properties not seen in its micro-scale counterparts due to the expected increase of mass transport rates between the reactants. The unique synthesis methodology, formulations, and performance of these materials will be presented. The degree of control over the burning rate of these nanocomposites afforded by the compositional variation of a binary oxidizing phase will also be discussed. These energetic nanocomposites have the potential for releasing controlled amounts of energy at a controlled rate. Due to the versatility of the synthesis method, a large number of compositions and physical properties can be achieved, resulting in

  3. Life Cycle Greenhouse Gas Emissions of Nuclear Electricity Generation: Systematic Review and Harmonization

    SciTech Connect

    Warner, E. S.; Heath, G. A.

    2012-04-01

    A systematic review and harmonization of life cycle assessment (LCA) literature of nuclear electricity generation technologies was performed to determine causes of and, where possible, reduce variability in estimates of life cycle greenhouse gas (GHG) emissions to clarify the state of knowledge and inform decision making. LCA literature indicates that life cycle GHG emissions from nuclear power are a fraction of traditional fossil sources, but the conditions and assumptions under which nuclear power are deployed can have a significant impact on the magnitude of life cycle GHG emissions relative to renewable technologies. Screening 274 references yielded 27 that reported 99 independent estimates of life cycle GHG emissions from light water reactors (LWRs). The published median, interquartile range (IQR), and range for the pool of LWR life cycle GHG emission estimates were 13, 23, and 220 grams of carbon dioxide equivalent per kilowatt-hour (g CO{sub 2}-eq/kWh), respectively. After harmonizing methods to use consistent gross system boundaries and values for several important system parameters, the same statistics were 12, 17, and 110 g CO{sub 2}-eq/kWh, respectively. Harmonization (especially of performance characteristics) clarifies the estimation of central tendency and variability. To explain the remaining variability, several additional, highly influential consequential factors were examined using other methods. These factors included the primary source energy mix, uranium ore grade, and the selected LCA method. For example, a scenario analysis of future global nuclear development examined the effects of a decreasing global uranium market-average ore grade on life cycle GHG emissions. Depending on conditions, median life cycle GHG emissions could be 9 to 110 g CO{sub 2}-eq/kWh by 2050.

  4. Visualization and velocity measurement of unsteady flow in a gas generator using cold-flow technique

    NASA Astrophysics Data System (ADS)

    Kuppa, Subrahmanyam

    1990-08-01

    Modeling of internal flow fields with hot, compressible fluids and sometimes combustion using cold flow techniques is discussed. The flow in a gas generator was modeled using cold air. The experimental set up was designed and fabricated to simulate the unsteady flow with different configurations of inlet tubes. Tests were run for flow visualization and measurement of axial velocity at different frequencies ranging from 5 to 12 Hz. Flow visualization showed that the incoming flow was a complex jet flow confined to a cylindrical enclosure, while the outgoing flow resembled the venting of a pressurized vessel. The pictures show a complex flow pattern due to the angling of the jet towards the wall for the bent tube configurations and straightened flows with straight tube and other configurations with straighteners. Velocity measurements were made at an inlet Re of 8.1 x 10(exp 4) based on maximum velocity and inlet diameter. Phase averaged mean velocities were observed to be well defined during charging and diminished during venting inside the cylinder. For the straight tube inlet comparison with a steady flow measurement of sudden expansion flow showed a qualitative similarity of the mean axial velocity distribution and centerline velocity decay during the charging phases. For the bent tube inlet case the contour plots showed the flow tendency towards the wall. Two cells were seen in the contours for the 8 and 12 Hz cases. The deviation of the point of occurrence of maximum velocity in a radial profile was found to be about 6.5 degrees. Entrance velocity profiles showed symmetry for the straight tube inlet but were skewed for the bent tube inlet. Contour plots of the phase averaged axial turbulence intensity for bent tube cases showed higher values in the core and near the wall in the region of impingement. Axial turbulence intensity measured for the straight tube case showed features as observed in an axisymmetric sudden expansion flow.

  5. Mitigation of Hydrogen Gas Generation from the Reaction of Water with Uranium Metal in K Basins Sludge

    SciTech Connect

    Sinkov, Sergey I.; Delegard, Calvin H.; Schmidt, Andrew J.

    2010-01-29

    Means to decrease the rate of hydrogen gas generation from the chemical reaction of uranium metal with water were identified by surveying the technical literature. The underlying chemistry and potential side reactions were explored by conducting 61 principal experiments. Several methods achieved significant hydrogen gas generation rate mitigation. Gas-generating side reactions from interactions of organics or sludge constituents with mitigating agents were observed. Further testing is recommended to develop deeper knowledge of the underlying chemistry and to advance the technology aturation level. Uranium metal reacts with water in K Basin sludge to form uranium hydride (UH3), uranium dioxide or uraninite (UO2), and diatomic hydrogen (H2). Mechanistic studies show that hydrogen radicals (H·) and UH3 serve as intermediates in the reaction of uranium metal with water to produce H2 and UO2. Because H2 is flammable, its release into the gas phase above K Basin sludge during sludge storage, processing, immobilization, shipment, and disposal is a concern to the safety of those operations. Findings from the technical literature and from experimental investigations with simple chemical systems (including uranium metal in water), in the presence of individual sludge simulant components, with complete sludge simulants, and with actual K Basin sludge are presented in this report. Based on the literature review and intermediate lab test results, sodium nitrate, sodium nitrite, Nochar Acid Bond N960, disodium hydrogen phosphate, and hexavalent uranium [U(VI)] were tested for their effects in decreasing the rate of hydrogen generation from the reaction of uranium metal with water. Nitrate and nitrite each were effective, decreasing hydrogen generation rates in actual sludge by factors of about 100 to 1000 when used at 0.5 molar (M) concentrations. Higher attenuation factors were achieved in tests with aqueous solutions alone. Nochar N960, a water sorbent, decreased hydrogen

  6. Gas generation and migration studies involving recently generated /sup 238/Pu-contaminated waste for the TRU Waste Sampling Program

    SciTech Connect

    Zerwekh, A.; Warren, J.L.

    1986-07-01

    This study is part of the multicontractor TRU Waste Sampling Program. Radiolytically generated gases were vented through a filtering device to determine its effectiveness in maintaining hydrogen concentrations within acceptably safe levels. In the second part of the study measurements were made to determine the ability of these gases, particularly hydrogen, to migrate through a sealed rigid polyethylene drum liner. Void volumes in these drums were found to be generally in excess of 90%. The carbon composite filter was found to satisfactorily vent hydrogen up to moderately high levels of alpha activity in the waste substrate. The sealed 90-mil liner was found to inhibit, but not prevent, the migration of hydrogen and other radiolytically generated gases.

  7. Bremsstrahlung {gamma}-ray generation by electrons from gas jets irradiated by laser pulses for radiographic testing

    SciTech Connect

    Oishi, Yuji; Nayuki, Takuya; Zhidkov, Alexei; Fujii, Takashi; Nemoto, Koshichi

    2012-07-11

    Electron generation from a gas jet irradiated by low energy femtosecond laser pulses is studied experimentally as a promising source of radiation for radioisotope-free {gamma}-ray imaging systems. The calculated yield of {gamma}-rays in the 0.5-2 MeV range, produced by low-average-power lasers and gas targets, exceeds the yields from solid tape targets up to 60 times. In addition, an effect of quasi-mono energetic electrons on {gamma}-ray imaging is also discussed.

  8. Addressing Learning Strategies for the Next Generation

    NASA Astrophysics Data System (ADS)

    Morris, P. A.; Reiff, P. H.; Sumners, C.

    2009-12-01

    Access to computers and interactive toys such as X Box have had impacts on learning strategies. New types of simulations and entertainment approaches will be increasingly important to reach out and encourage careers in science, technology, engineering and math (STEM) disciplines including space science. Examples of effective tools are planetarium shows and CD’s and DVD’s that can be distributed to teachers, students and the general public. Planetarium shows are no longer restricted to fixed dome venues but are increasingly being adapted to portable domes that have the advantage of transporting the activity to a school, community event or neighborhood center. Groups of individuals who may not normally consider a planetarium show as a family or group event are exposed to a learning experience which is also entertaining. Selected planetarium shows are available in languages other than English, including Spanish. Hands-on interactive activities are available that will enhance the experience of the attendees. Pre and post testing have shown [Sumners et al., 2006, 2008] that these activities are effective for improving STEM knowledge. New planetarium technology includes using a Wii controller for navigating through buildings. These so far have been applied to games but could be applied to a virtual tour of the space station, for example. CD’s and DVD’s are important for augmenting the activities of the planetarium shows as they provide additional learning activities that can be used either in the home, the classroom or as an enhancement for planetarium events. Simulations on the Sun, planetary or solar events, related games such as TIC TAC TOE are easily incorporated. It is important to provide additional support for the teachers that will enable them to incorporate the data into their curriculum and state mandated achievement levels.

  9. ESTIMATION OF RADIOLYTIC GAS GENERATION RATE FOR CYLINDRICAL RADIOACTIVE WASTE PACKAGES - APPLICATION TO SPENT ION EXCHANGE RESIN CONTAINERS

    SciTech Connect

    Husain, A.; Lewis, Brent J.

    2003-02-27

    Radioactive waste packages containing water and/or organic substances have the potential to radiolytically generate hydrogen and other combustible gases. Typically, the radiolytic gas generation rate is estimated from the energy deposition rate and the radiolytic gas yield. Estimation of the energy deposition rate must take into account the contributions from all radionuclides. While the contributions from non-gamma emitting radionuclides are relatively easy to estimate, an average geometry factor must be computed to determine the contribution from gamma emitters. Hitherto, no satisfactory method existed for estimating the geometry factors for a cylindrical package. In the present study, a formulation was developed taking into account the effect of photon buildup. A prototype code, called PC-CAGE, was developed to numerically solve the integrals involved. Based on the selected dimensions for a cylinder, the specified waste material, the photon energy of interest and a value for either the absorption or attenuation coefficient, the code outputs values for point and average geometry factors. These can then be used to estimate the internal dose rate to the material in the cylinder and hence to calculate the radiolytic gas generation rate. Besides the ability to estimate the rates of radiolytic gas generation, PC-CAGE can also estimate the dose received by the container material. This is based on values for the point geometry factors at the surface of the cylinder. PC-CAGE was used to calculate geometry factors for a number of cylindrical geometries. Estimates for the absorbed dose rate in container material were also obtained. The results for Ontario Power Generation's 3 m3 resin containers indicate that about 80% of the source gamma energy is deposited internally. In general, the fraction of gamma energy deposited internally depends on the dimensions of the cylinder, the material within it and the photon energy; the fraction deposited increases with increasing

  10. Evaluation of distributed gas cooling of pressurized PAFC for utility power generation

    NASA Technical Reports Server (NTRS)

    Farooque, M.; Hooper, M.; Maru, H.

    1981-01-01

    A proof-of-concept test for a gas-cooled pressurized phosphoric acid fuel cell is described. After initial feasibility studies in short stacks, two 10 kW stacks are tested. Progress includes: (1) completion of design of the test stations with a recirculating gas cooling loop; (2) atmospheric testing of the baseline stack.

  11. Using seismic reflection surveying to map gas-generated excess pore pressures at Finneidfjord, Norway

    NASA Astrophysics Data System (ADS)

    Baise, L. G.; Morgan, E. C.; Vanneste, M. W.; Longva, O.; Lecomte, I.; McAdoo, B. G.

    2009-12-01

    On the 20th of June, 1996, a multi-phase landslide that initiated under water and retrogressed onto land ultimately killed 4 people, destroyed several houses, and undermined a major highway in Finneidfjord, Norway, an area with a known history of landsliding in the Holocene. Geological and environmental conditions inherent to the 1996 slide include excess fluid/gas pressure (particularly in gas-bearing sediment), lateral and vertical lithological variability, slide-prone sediment layers, and changes in the water table due to heavy rainfall. In this study, we quantify pore pressures within the free gas accumulation at very shallow sub-surface depths using seismic reflection data. The trapped gas is thought to originate from the decomposition of river-deposited organic material. The gas front (a few meters below the seabed) produces a strong, polarity-reversed reflection, dramatically attenuating sub-surface reflections. On X-ray images of cores collected from the 5 km2 large gas zone, gas appears as vesicular spots. We use a previously published method incorporating continuous wavelet transforms to quantify attenuation produced by gas-bearing sediment. Taking the output from this method, and knowing or assuming values for other physical parameters, we invert for in situ pressure and equivalent thickness of the free gas layer. We compare our results to pressure data collected from a single piezometer penetrating the gas front, and then incorporate geostatistical methods to interpolate between our seismic profiles. The end product is a map of excess pore pressure estimates, which can be used in conjunction with bathymetry data and cores for more accurate slope stability analyses, ultimately identifying the more sensitive areas of the fjord.

  12. High harmonic generation in a gas-filled hollow-core photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Heckl, O. H.; Baer, C. R. E.; Kränkel, C.; Marchese, S. V.; Schapper, F.; Holler, M.; Südmeyer, T.; Robinson, J. S.; Tisch, J. W. G.; Couny, F.; Light, P.; Benabid, F.; Keller, U.

    2009-10-01

    High harmonic generation (HHG) of intense infrared laser radiation (Ferray et al., J. Phys. B: At. Mol. Opt. Phys. 21:L31, 1988; McPherson et al., J. Opt. Soc. Am. B 4:595, 1987) enables coherent vacuum-UV (VUV) to soft-X-ray sources. In the usual setup, energetic femtosecond laser pulses are strongly focused into a gas jet, restricting the interaction length to the Rayleigh range of the focus. The average photon flux is limited by the low conversion efficiency and the low average power of the complex laser amplifier systems (Keller, Nature 424:831, 2003; Südmeyer et al., Nat. Photonics 2:599, 2008; Röser et al., Opt. Lett. 30:2754, 2005; Eidam et al., IEEE J. Sel. Top. Quantum Electron. 15:187, 2009) which typically operate at kilohertz repetition rates. This represents a severe limitation for many experiments using the harmonic radiation in fields such as metrology or high-resolution imaging. Driving HHG with novel high-power diode-pumped multi-megahertz laser systems has the potential to significantly increase the average photon flux. However, the higher average power comes at the expense of lower pulse energies because the repetition rate is increased by more than a thousand times, and efficient HHG is not possible in the usual geometry. So far, two promising techniques for HHG at lower pulse energies were developed: external build-up cavities (Gohle et al., Nature 436:234, 2005; Jones et al., Phys. Rev. Lett. 94:193, 2005) and resonant field enhancement in nanostructured targets (Kim et al., Nature 453:757, 2008). Here we present a third technique, which has advantages in terms of ease of HHG light extraction, transverse beam quality, and the possibility to substantially increase conversion efficiency by phase-matching (Paul et al., Nature 421:51, 2003; Ren et al., Opt. Express 16:17052, 2008; Serebryannikov et al., Phys. Rev. E (Stat. Nonlinear Soft Matter Phys.) 70:66611, 2004; Serebryannikov et al., Opt. Lett. 33:977, 2008; Zhang et al., Nat. Phys. 3

  13. Efficient generation of fast neutrons by magnetized deuterons in an optimized deuterium gas-puff z-pinch

    NASA Astrophysics Data System (ADS)

    Klir, D.; Shishlov, A. V.; Kokshenev, V. A.; Kubes, P.; Labetsky, A. Yu; Rezac, K.; Cherdizov, R. K.; Cikhardt, J.; Cikhardtova, B.; Dudkin, G. N.; Fursov, F. I.; Garapatsky, A. A.; Kovalchuk, B. M.; Kravarik, J.; Kurmaev, N. E.; Orcikova, H.; Padalko, V. N.; Ratakhin, N. A.; Sila, O.; Turek, K.; Varlachev, V. A.

    2015-04-01

    Z-pinch experiments with deuterium gas puffs have been carried out on the GIT-12 generator at 3 MA currents. Recently, a novel configuration of a deuterium gas-puff z-pinch was used to accelerate deuterons and to generate fast neutrons. In order to form a homogeneous, uniformly conducting layer at a large initial radius, an inner deuterium gas puff was surrounded by an outer hollow cylindrical plasma shell. The plasma shell consisting of hydrogen and carbon ions was formed at the diameter of 350 mm by 48 plasma guns. A linear mass of the plasma shell was about 5 µg cm-1 whereas a total linear mass of deuterium gas in single or double shell gas puffs was about 100 µg cm-1. The implosion lasted 700 ns and seemed to be stable up to a 5 mm radius. During stagnation, m = 0 instabilities became more pronounced. When a disruption of necks occurred, the plasma impedance reached 0.4 Ω and high energy (>2 MeV) bremsstrahlung radiation together with high energy deuterons were produced. Maximum neutron energies of 33 MeV were observed by axial time-of-flight detectors. The observed neutron spectra could be explained by a suprathermal distribution of deuterons with a high energy tail f≤ft({{E}\\text{d}}\\right)\\propto E\\text{d}-(1.8+/- 0.2) . Neutron yields reached 3.6 × 1012 at a 2.7 MA current. A high neutron production efficiency of 6 × 107 neutrons per one joule of plasma energy resulted from the generation of high energy deuterons and from their magnetization inside plasmas.

  14. Effects of xenon gas on generation and propagation of shock waves in the cavity of excimer laser

    NASA Astrophysics Data System (ADS)

    Kosugi, Shinichiroh; Maeno, Kazuo; Honma, Hiroki

    1993-05-01

    High repetition rate excimer lasers are expected for wide industrial application. The power of excimer laser, however, decreases rapidly in a higher repetition rate operation. Shock or acoustic waves, which are caused by the periodic pulse discharge, may limit the repetition rate of an excimer laser up to 2.5 kHz. Such waves cause inhomogeneity of gas density in the discharge region of the excimer laser. In high repetition rate operation this inhomogeneity remains at the next discharge. Arcing may be generated by this inhomogeneity and the homogeneous excitation of the laser gas is obstructed. Although these phenomena have been reported, the research for the effects of shock waves has remained insufficient. And the relation between these shock waves and discharge phenomena has not been clarified. To resolve this problem, we developed a scaling model chamber of a UV preionized excimer laser cavity with windows for flow visualization. We report the first result by using this model and Schlieren technique in a pure helium gas case. In our experiment three types of shock waves are found in the discharge cavity. Those shock waves are generated from the boundary of the main discharge area, from sparking pin gaps, and from the main electrode surfaces. In this study we focus on the effect of xenon gas on the generation and the propagation of shock waves. Components of the Xe-Cl excimer laser gas are helium, xenon, and hydrogen chloride. In those gases xenon has the largest molecular weight of 131.29. So we conclude xenon plays an important role in the shock wave propagation and in discharge phenomenon.

  15. Graphite oxidation in the Apollo 17 orange glass magma: Implications for the generation of a lunar volcanic gas phase

    NASA Astrophysics Data System (ADS)

    Nicholis, Mike G.; Rutherford, Malcolm J.

    2009-10-01

    An Apollo 17 picritic orange glass composition has been used to experimentally investigate the conditions at which graphite would oxidize to form a CO-rich gas, and ultimately produce lunar fire-fountain eruptions. Isothermal decompression experiments run above the A17 orange glass liquidus temperature (>1350 °C) suggest that the initial CO-rich gas phase produced by graphite oxidation would be generated during magma ascent at a pressure of 40 MPa, ˜8.5 km beneath the lunar surface. Additional experiments with 2000 ppm S and 1000 ppm Cl showed that the presence of these dissolved gas species would not affect the depth of graphite oxidation, verifying that the first volcanic gas phase would be generated by the oxidation of graphite. A simple ideal chemical mixing model for calculating melt FeO activity in a Fe-metal/silicate melt system was tested with a series of 0.1 MPa controlled oxygen fugacity experiments. Agreement between the model and experiments allows the model to be used to calculate oxygen fugacity in picritic lunar glass compositions such as the A17 orange glass. Using this model in a reanalysis of chemical equilibria between the natural A17 orange glass melt and the metal spherules (Fe 85Ni 14Co 1) trapped within the glass beads indicates a log oxygen fugacity of -11.2, 0.7 log units, more oxidized than previous estimates. At the A17 orange glass liquidus temperature (1350 ± 5 °C), this fO2 corresponds to a minimum pressure of 41 MPa on the graphite-C-O surface. The fact that the same critical graphite oxidation pressure was determined in decompression experiments and from the Fe-FeO activity model for the natural A17 orange glass-metal assemblage strongly supports this pressure (8.5 km depth) for volcanic gas formation in lunar basalts. Generation of a gas by oxidation of C in ascending magma is likely to have been important in getting dense lunar magmas to the surface as well as in generating fire-fountain eruptions. The vesicles common in many

  16. Generation of 12 fs deep-ultraviolet pulses by four-wave mixing through filamentation in neon gas.

    PubMed

    Fuji, Takao; Horio, Takuya; Suzuki, Toshinori

    2007-09-01

    Generation of deep-ultraviolet femtosecond pulses by four-wave mixing through filamentation in neon gas was demonstrated. Fundamental (omega) and second-harmonic (2omega) pulses of 25 fs Ti:sapphire amplifier output were focused into neon gas, and 20 microJ pulses with the center wavelength of 260 nm were produced by a four-wave mixing process, 2omega+2omega-omega?3omega through an ~15 cm filament. Additionally, pulses with an energy of 2 microJ at 200 nm were generated, probably by a cascaded process, 3omega+2omega-omega?4omega. The 260 nm pulses were compressed by a grating-based compressor and characterized by a dispersion-free transient grating frequency-resolved optical gating. The estimated pulse width was 12 fs. PMID:17767278

  17. Generation of widely tunable intense far-infrared radiation pulses by stimulated Raman transitions in methylfluoride gas

    SciTech Connect

    Lang, P.T.; Sessler, F.; Werling, U.; Renk, K.F. )

    1989-12-18

    We report on the generation of widely tunable intense far-infrared radiation pulses by stimulated Raman transitions in methylfluoride gas. Using a tunable high-pressure CO{sub 2} laser we achieved, by {ital P}-branch tuning of stimulated Raman transitions in {sup 12}CH{sub 3}F and {sup 13}CH{sub 3}F gases, tunable generation of radiation in a series of intervals in the spectral range from 37 to 72 cm{sup {minus}1} covering 20% of this range. Possibilities of further extension of the tuning regions are also discussed.

  18. Utilizing Gas Filled Cavities for the Generation of an Intense Muon Source

    SciTech Connect

    Stratakis, Diktys; Neuffer, David V.

    2015-05-01

    A key requirement for designing intense muon sources is operating rf cavities in multi-tesla magnetic fields. Recently, a proof-of-principle experiment demonstrated that an rf cavity filed with high pressure hydrogen gas could meet this goal. In this study, rigorous simulation is used to design and evaluate the performance of an intense muon source with gas filled cavities. We present a new lattice design and compare our results with conventional schemes. We detail the influence of gas pressure on the muon production rate.

  19. Utilizing gas-filled cavities for the generation of an intense muon source

    SciTech Connect

    Stratakis, Diktys; Neuffer, David V.

    2015-05-03

    A key requirement for designing intense muon sources is operating rf cavities in multi-tesla magnetic fields. Recently, a proof-of-principle experiment demonstrated that an rf cavity filed with high pressure hydrogen gas could meet this goal. In this study, rigorous simulation is used to design and evaluate the performance of an intense muon source with gas filled cavities. We present a new lattice design and compare our results with conventional schemes. We detail the influence of gas pressure on the muon production rate.

  20. Steam Generator Component Model in a Combined Cycle of Power Conversion Unit for Very High Temperature Gas-Cooled Reactor

    SciTech Connect

    Oh, Chang H; Han, James; Barner, Robert; Sherman, Steven R

    2007-06-01

    The Department of Energy and the Idaho National Laboratory are developing a Next Generation Nuclear Plant (NGNP), Very High Temperature Gas-Cooled Reactor (VHTR) to serve as a demonstration of state-of-the-art nuclear technology. The purpose of the demonstration is two fold 1) efficient low cost energy generation and 2) hydrogen production. Although a next generation plant could be developed as a single-purpose facility, early designs are expected to be dual-purpose. While hydrogen production and advanced energy cycles are still in its early stages of development, research towards coupling a high temperature reactor, electrical generation and hydrogen production is under way. A combined cycle is considered as one of the power conversion units to be coupled to the very high-temperature gas-cooled reactor (VHTR). The combined cycle configuration consists of a Brayton top cycle coupled to a Rankine bottoming cycle by means of a steam generator. A detailed sizing and pressure drop model of a steam generator is not available in the HYSYS processes code. Therefore a four region model was developed for implementation into HYSYS. The focus of this study was the validation of a HYSYS steam generator model of two phase flow correlations. The correlations calculated the size and heat exchange of the steam generator. To assess the model, those calculations were input into a RELAP5 model and its results were compared with HYSYS results. The comparison showed many differences in parameters such as the heat transfer coefficients and revealed the different methods used by the codes. Despite differences in approach, the overall results of heat transfer were in good agreement.

  1. Cost and greenhouse gas emission tradeoffs of alternative uses of lignin for second generation ethanol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Second generation ethanol bioconversion technologies are under demonstration-scale development for producing lignocellulosic fuels to meet the federal Renewable Fuel Standards (RFS2) supply requirements by 2022. Bioconversion technology utilizes the fermentable sugars generated from the cellulosic ...

  2. Hydrogen Gas Generation Model for Fuel-Based Remote-Handled Transuranic Waste Stored at the INEEL

    SciTech Connect

    Khericha, S.; Bhatt, R.; Liekhus, K.

    2003-01-14

    The Idaho National Environmental and Engineering Laboratory (INEEL) initiated efforts to calculate the hydrogen gas generation in remote-handled transuranic (RH-TRU) containers in order to evaluate continued storage of unvented RH-TRU containers in vaults and to identify any potential problems during retrieval and aboveground storage. A computer code is developed to calculate the hydrogen concentration in the stored RH-TRU waste drums for known configuration, waste matrix, and radionuclide inventories as a function of time.

  3. Generation of a nonequlibrium plasma in heterophase atmospheric-pressure gas-liquid media and demonstration of its sterilization ability

    SciTech Connect

    Akishev, Yu. S.; Grushin, M. E.; Karal'nik, V. B.; Monich, A. E.; Pan'kin, M. V.; Trushkin, N. I.; Kholodenko, V. P.; Chugunov, V. A.; Zhirkova, N. A.; Irkhina, I. A.; Kobzev, E. N.

    2006-12-15

    Results are presented from experiments on the generation of a low-temperature nonequilibrium plasma in atmospheric-pressure heterophase gas-liquid media of different compositions: (i) a liquid with air bubbles and (ii) air with liquid aerosol. To illustrate possible application of a low-temperature plasma in a heterophase medium, experiments on the inactivation of some microorganisms by a low-temperature plasma have been performed.

  4. Method for generating a highly reactive plasma for exhaust gas after treatment and enhanced catalyst reactivity

    SciTech Connect

    Whealton, John H.; Hanson, Gregory R.; Storey, John M.; Raridon, Richard J.; Armfield, Jeffrey S.; Bigelow, Timothy S.; Graves, Ronald L.

    2000-07-01

    This patent application describes a method and apparatus of exhaust gas remediation that enhance the reactivity of the material catalysts found within catalytic converters of cars, trucks, and power stations.

  5. Method of generating hydrocarbon reagents from diesel, natural gas and other logistical fuels

    DOEpatents

    Herling, Darrell R.; Aardahl, Chris L.; Rozmiarek, Robert T.; Rappe, Kenneth G.; Wang, Yong; Holladay, Jamelyn D.

    2010-06-29

    The present invention provides a process for producing reagents for a chemical reaction by introducing a fuel containing hydrocarbons into a flash distillation process wherein the fuel is separated into a first component having a lower average molecular weight and a second component having a higher average molecular weight. The first component is then reformed to produce synthesis gas wherein the synthesis gas is reacted catalytically to produce the desire reagent.

  6. Method of Generating Hydrocarbon Reagents from Diesel, Natural Gas and Other Logistical Fuels

    DOEpatents

    Herling, Darrell R [Richland, WA; Aardahl, Chris L [Richland, WA; Rozmiarek, Robert T [Middleton, WI; Rappe, Kenneth G [Richland, WA; Wang, Yong [Richland, WA; Holladay, Jamelyn D [Kennewick, WA

    2008-10-14

    The present invention provides a process for producing reagents for a chemical reaction by introducing a fuel containing hydrocarbons into a flash distillation process wherein the fuel is separated into a first component having a lower average molecular weight and a second component having a higher average molecular weight. The first component is then reformed to produce synthesis gas wherein the synthesis gas is reacted catalytically to produce the desire reagent.

  7. A powerful electrohydrodynamic flow generated by a high-frequency dielectric barrier discharge in a gas

    NASA Astrophysics Data System (ADS)

    Nebogatkin, S. V.; Rebrov, I. E.; Khomich, V. Yu.; Yamshchikov, V. A.

    2016-01-01

    Theoretical and experimental studies of an electrohydrodynamic flow induced by a high-frequency dielectric barrier discharge distributed over a dielectric surface in a gas have been conducted. Dependences of the ion current, the gas flow velocity, and the spatial distributions thereof on the parameters of the power supply of the plasma ion emitter and an external electric field determined by the collector grid voltage have been described.

  8. Research, development and demonstration in the design of sanitary landfill to optimize the generation and capture of compressible gas

    NASA Astrophysics Data System (ADS)

    Nosanov, M. E.; Teeple, F. E.; Buesch, S. C.

    1982-02-01

    The influences of selected factors on the generation and recovery of methane gas from sanitary landfills were investigated. The factors included encapsulation, shredding, air classifying, moisture, and pH. Facilities consisting of six model sanitary landfill cells, each with a capacity of approximately 450 cubic yards of municipal waste, and auxiliary subsystems were constructed. Municipal waste in each cell is contained in a 30-mil thick polyvinly chloride plastic sheeting forming a virtually gas-tight envelope. Two cells were filled with as-collected urban waste, two with shredded waste, and two with shredded and air classified waste, constituting three pairs of cells. One of each pair is a control cell with the other used as an experimental variable. Systems were provided for adding measured amounts of water, removing and recirculating leachate, and for extracting gas and measuring gas flow. During testing, gas production and internal cell characteristics were measured to determine the effects of mechanical processing, moisture content, and leachate pH.

  9. Gas Generation and Hold-Up in Hanford Waste Treatment Plant Process Streams Containing Anti-Foam Agent (AFA)

    SciTech Connect

    Arm, Stuart T.; Poloski, Adam P.; Stewart, Charles W.; Meyer, Perry A.; Kurath, Dean E.

    2007-06-29

    The Waste Treatment and Immobilization Plant (WTP) is being designed and built to pretreat and vitrify defense wastes stored at the DOE Hanford Site near Richland, Washington. Some of the WTP process streams are slurries that exhibit non-Newtonian rheological behavior. Such streams can accumulate hazardous quantities of thermally and radiolytically generated flammable gases. Experiments were performed in a bubble column to measure gas hold-up under various conditions to better understand flammable gas behavior in WTP processes. The two non-Newtonian slurries tested were kaolin-bentonite clay and a chemical surrogate of pretreated high-level waste (HLW) from Hanford Tank AZ-101. The addition of solutes, whether a salt or anti-foaming agent (AFA) decrease the bubble coalescence rate leading to smaller bubbles, lower bubble rise velocity and higher gas holdup. Gas holdup decreased with increasing yield stress and consistency. The impact of AFA on gas holdup in kaolin-bentonite clay was less than in simulated HLW, presumably because the AFA adsorbed onto the clay particles, rendering it unavailable to retard coalescence.

  10. Production efficiencies of U.S. electric generation plants: Effects of data aggregation and greenhouse gas and renewable energy policy

    NASA Astrophysics Data System (ADS)

    Lynes, Melissa Kate

    Over the last few decades there has been a shift in electricity production in the U.S. Renewable energy sources are becoming more widely used. In addition, electric generation plants that use coal inputs are more heavily regulated than a couple decades ago. This shift in electricity production was brought on by changes in federal policy -- a desire for electricity produced in the U.S. which led to policies being adopted that encourage the use of renewable energy. The change in production practices due to policies may have led to changes in the productivity of electric generation plants. Multiple studies have examined the most efficient electric generation plants using the data envelopment analysis (DEA) approach. This study builds on past research to answer three questions: 1) Does the level of aggregation of fuel input variables affect the plant efficiency scores and how does the efficiency of renewable energy input compare to nonrenewable energy inputs; 2) Are policies geared toward directly or indirectly reducing greenhouse gas emissions affecting the production efficiencies of greenhouse gas emitting electric generation plants; and 3) Do renewable energy policies and the use of intermittent energy sources (i.e. wind and solar) affect the productivity growth of electric generation plants. All three analysis, presented in three essays, use U.S. plant level data obtained from the Energy Information Administration to answer these questions. The first two essays use DEA to determine the pure technical, overall technical, and scale efficiencies of electric generation plants. The third essay uses DEA within the Malmquist index to assess the change in productivity over time. Results indicate that the level of aggregation does matter particularly for scale efficiency. This implies that valuable information is likely lost when fuel inputs are aggregated together. Policies directly focused on reducing greenhouse gas emissions may improve the production efficiencies of

  11. Effect of operating and sampling conditions on the exhaust gas composition of small-scale power generators.

    PubMed

    Smits, Marianne; Vanpachtenbeke, Floris; Horemans, Benjamin; De Wael, Karolien; Hauchecorne, Birger; Van Langenhove, Herman; Demeestere, Kristof; Lenaerts, Silvia

    2012-01-01

    Small stationary diesel engines, like in generator sets, have limited emission control measures and are therefore responsible for 44% of the particulate matter (PM) emissions in the United States. The diesel exhaust composition depends on operating conditions of the combustion engine. Furthermore, the measurements are influenced by the used sampling method. This study examines the effect of engine loading and exhaust gas dilution on the composition of small-scale power generators. These generators are used in different operating conditions than road-transport vehicles, resulting in different emission characteristics. Experimental data were obtained for gaseous volatile organic compounds (VOC) and PM mass concentration, elemental composition and nitrate content. The exhaust composition depends on load condition because of its effect on fuel consumption, engine wear and combustion temperature. Higher load conditions result in lower PM concentration and sharper edged particles with larger aerodynamic diameters. A positive correlation with load condition was found for K, Ca, Sr, Mn, Cu, Zn and Pb adsorbed on PM, elements that originate from lubricating oil or engine corrosion. The nitrate concentration decreases at higher load conditions, due to enhanced nitrate dissociation to gaseous NO at higher engine temperatures. Dilution on the other hand decreases PM and nitrate concentration and increases gaseous VOC and adsorbed metal content. In conclusion, these data show that operating and sampling conditions have a major effect on the exhaust gas composition of small-scale diesel generators. Therefore, care must be taken when designing new experiments or comparing literature results. PMID:22442670

  12. Effect of Operating and Sampling Conditions on the Exhaust Gas Composition of Small-Scale Power Generators

    PubMed Central

    Smits, Marianne; Vanpachtenbeke, Floris; Horemans, Benjamin; De Wael, Karolien; Hauchecorne, Birger; Van Langenhove, Herman; Demeestere, Kristof; Lenaerts, Silvia

    2012-01-01

    Small stationary diesel engines, like in generator sets, have limited emission control measures and are therefore responsible for 44% of the particulate matter (PM) emissions in the United States. The diesel exhaust composition depends on operating conditions of the combustion engine. Furthermore, the measurements are influenced by the used sampling method. This study examines the effect of engine loading and exhaust gas dilution on the composition of small-scale power generators. These generators are used in different operating conditions than road-transport vehicles, resulting in different emission characteristics. Experimental data were obtained for gaseous volatile organic compounds (VOC) and PM mass concentration, elemental composition and nitrate content. The exhaust composition depends on load condition because of its effect on fuel consumption, engine wear and combustion temperature. Higher load conditions result in lower PM concentration and sharper edged particles with larger aerodynamic diameters. A positive correlation with load condition was found for K, Ca, Sr, Mn, Cu, Zn and Pb adsorbed on PM, elements that originate from lubricating oil or engine corrosion. The nitrate concentration decreases at higher load conditions, due to enhanced nitrate dissociation to gaseous NO at higher engine temperatures. Dilution on the other hand decreases PM and nitrate concentration and increases gaseous VOC and adsorbed metal content. In conclusion, these data show that operating and sampling conditions have a major effect on the exhaust gas composition of small-scale diesel generators. Therefore, care must be taken when designing new experiments or comparing literature results. PMID:22442670

  13. Direct numerical simulation of interfacial wave generation in turbulent gas-liquid flows in horizontal channels

    NASA Astrophysics Data System (ADS)

    Campbell, Bryce; Hendrickson, Kelli; Liu, Yuming; Subramani, Hariprasad

    2014-11-01

    For gas-liquid flows through pipes and channels, a flow regime (referred to as slug flow) may occur when waves form at the interface of a stratified flow and grow until they bridge the pipe diameter trapping large elongated gas bubbles within the liquid. Slug formation is often accompanied by strong nonlinear wave-wave interactions, wave breaking, and gas entrainment. This work numerically investigates the fully nonlinear interfacial evolution of a two-phase density/viscosity stratified flow through a horizontal channel. A Navier-Stokes flow solver coupled with a conservative volume-of-fluid algorithm is use to carry out high resolution three-dimensional simulations of a turbulent gas flowing over laminar (or turbulent) liquid layers. The analysis of such flows over a range of gas and liquid Reynolds numbers permits the characterization of the interfacial stresses and turbulent flow statistics allowing for the development of physics-based models that approximate the coupled interfacial-turbulent interactions and supplement the heuristic models built into existing industrial slug simulators.

  14. Landfill gas cleanup for carbonate fuel cell power generation. CRADA final report

    SciTech Connect

    Steinfeld, G.; Sanderson, R.

    1998-02-01

    The overall objective of the work reported here was to evaluate the extent to which conventional contaminant removal processes could be combined to economically reduce contaminant levels to the specifications for carbonate fuel cells. The technical effort was conducted by EPRI, consultant David Thimsen, Kaltec of Minnesota, Energy Research Corporation (ERC) and Interpoll Laboratories. The Electric Power Research Institute (EPRI) made available two test skids originally used to test an ERC 30 kW carbonate fuel cell at the Destec Coal Gasification Plan in Plaquemine, LA. EPRI`s carbonate fuel cell pilot plant was installed at the Anoka County Regional Landfill in Ramsey, Minnesota. Additional gas cleaning equipment was installed to evaluate a potentially inexpensive, multi-stage gas cleaning process to remove sulfur and chlorine in the gas to levels acceptable for long-term, economical carbonate fuel cell operation. The pilot plant cleaned approximately 970,000 scf (27,500 Nm{sup 3}) of gas over 1,000 hours of operation. The testing showed that the process could achieve the following polished gas concentrations. Less than 80 ppbv hydrogen sulfide; less than 1 ppmv (the detection limit) organic sulfur; less than 300 ppbv hydrogen chloride; less than 20--80 ppbv of any individual chlorined hydrocarbon; and 1.5 ppm sulfur dioxide. These were the detection limits of the analytical procedures employed. It is probable that the actual concentrations are below these analytical limits.

  15. Molecular alignment allows low-order harmonic generation by circular light in a gas

    NASA Astrophysics Data System (ADS)

    Houzet, J.; Hertz, E.; Billard, F.; Lavorel, B.; Faucher, O.

    2013-08-01

    We experimentally investigate odd-order harmonic generation in molecular gases produced by circularly polarized laser fields. While forbidden in isotropic medium, this effect is allowed by symmetry breaking resulting from nonadiabatic laser-induced molecular alignment. The demonstration is provided by generating the third harmonic in CO2 molecules. Attractive properties and challenging potential applications are discussed in the context of higher-order harmonic generation.

  16. High-order-harmonic generation in gas with a flat-top laser beam

    SciTech Connect

    Boutu, W.; Auguste, T.; Binazon, L.; Gobert, O.; Carre, B.; Boyko, O.; Valentin, C.; Balcou, Ph.; Merdji, H.

    2011-12-15

    We present experimental and numerical results on high-order-harmonic generation with a flat-top laser beam. We show that a simple binary tunable phase plate, made of two concentric glass plates, can produce a flat-top profile at the focus of a Gaussian infrared beam. Both experiments and numerical calculations show that there is a scaling law between the harmonic generation efficiency and the increase of the generation volume.

  17. Optimization of gas path aerodynamics for PK-39 boiler of power generating unit No. 4 of Troitskaya SDPP using numerical simulation of gas flows

    NASA Astrophysics Data System (ADS)

    Prokhorov, V. B.; Grigorev, I. V.; Fomenko, M. V.; Kaverin, A. A.

    2015-12-01

    Power generating unit no. 4 of Troitskaya State District Power Plant (SDPP) is incapable of operating with a nominal load of 278 MW because of high aerodynamic drag of the gas path. At present, the maximum load of the two-boiler single-turbine unit is 210 MW practically without a possibility of adjustment. The results of numerical simulation of the gas flow for the existing gas path from the electrostatic precipitator (EP) to the smoke exhausts (SEs) and two flue designs proposed for renovation of this section are presented. The results of simulation show that the existing flue section has high aerodynamic drag, which is explained by poor, as regards aerodynamics, design. The local loss coefficient, in terms of the dynamic pressure in the sucker pocket of the smoke exhaust is equal to 4.57. The local aerodynamic loss coefficient after renovation at the considered section according to the first version would make 1.48, and according to the second version 1.325, which would reduce losses at this section by more than a factor of three, and ensure the power unit operation with the rated load.

  18. Generation of thin, near critical density gas targets for laser plasma interaction experiments

    NASA Astrophysics Data System (ADS)

    Salehi, Fatholah; Goers, Andy; Hine, George; Feder, Linus; Miao, Bo; Milchberg, Howard

    2015-11-01

    We present the design and characterization of a thin (200µm FWHM), high density pulsed gas jet which we use to study near critical and overcritical laser plasma interactions. We show that cryogenic cooling of the pulsed jet provides the necessary density enhancement for reaching overcritical plasma densities at 800 nm (> 1 . 7 × >102 1 cm-3) with pure hydrogen gas at plenum pressures below 1000 psi. Further, we present 2D and 3D PIC simulations showing the interaction of femtosecond pulses with our experimentally measured near critical gas density profile. The simulations show electron and ion acceleration at drive pulse energies as low as a few tens of millijoules. This work supported by DTRA and the US Department of Energy.

  19. High-sweeping-speed optically synchronized dual-channel terahertz-signal generator for driving a superconducting tunneling mixer and its application to active gas sensing.

    PubMed

    Oh, Kyoung-Hwan; Shimizu, Naofumi; Kohjiro, Satoshi; Kikuchi, Ken'ichi; Wakatsuki, Atsushi; Kukutsu, Naoya; Kado, Yuichi

    2009-10-12

    We propose a high-sweeping-speed optically synchronized dual-channel terahertz (THz) signal generator for an active gas-sensing system with a superconductor-insulator-superconductor (SIS) mixer. The generator can sweep a frequency range from 200 to 500 GHz at a speed of 375 GHz/s and a frequency resolution of 500 MHz. With the developed gas-sensing system, a gas-absorption-line measurement was successfully carried out with N(2)O gas in that frequency range. PMID:20372575

  20. From fighter aircraft to pipeline: The development of the first ''third generation'' aero-derived gas turbine in the 16,000-8,000 HP class

    SciTech Connect

    Rogers, G.N.; Mathers, W.G.

    1987-01-01

    Two totally unrelated sources of hot gas energy the FCCU oil refining process and the aircraft engine - both utilize the same range of basic aerodynamic and machinery design technologies for mechanical drive power recovery. this paper shows how these technologies came together and discusses the development of the Ingersoll-Rand GT-60 gas turbine, the first to use a general Electric LM1600 hot gas generator (from the F404 fighter engine program); it also illustrates how it was possible for the first ''third generation'' aero-derived gas turbine in the 16,000 - 18,000 hp class to be developed in a much shorter than normal lead time.

  1. Generations.

    PubMed

    Chambers, David W

    2005-01-01

    Groups naturally promote their strengths and prefer values and rules that give them an identity and an advantage. This shows up as generational tensions across cohorts who share common experiences, including common elders. Dramatic cultural events in America since 1925 can help create an understanding of the differing value structures of the Silents, the Boomers, Gen Xers, and the Millennials. Differences in how these generations see motivation and values, fundamental reality, relations with others, and work are presented, as are some applications of these differences to the dental profession. PMID:16623137

  2. Determination of antimony in environment samples by gas phase chemiluminescence detection following flow injection hydride generation and cryotrapping.

    PubMed

    Ye, Yousheng; Sang, Jianchi; Ma, Hongbing; Tao, Guanhong

    2010-06-15

    A novel method for the determination of antimony in environmental samples was developed with gas phase chemiluminescence detection following flow injection hydride generation and cryotrapping. The stibine, generated from samples by borohydride reduction of antimony using flow injection technique, was separated by using a new gas-liquid separator, dried with an ice-salt cryogenic bath and concentrated in a glass U-tube immersed in liquid nitrogen. Re-vaporization of stibine based on its boiling point was achieved by allowing the tube to warm at room temperature. A gas phase chemiluminescence signal was produced during the ozonation of the hydride in a reflective chamber. Under optimal conditions, the proposed method was characterized by a wide linear calibration range from 1.0microgL(-1) to 10.0mgL(-1) with a detection limit of 0.18microgL(-1) (n=11). The relative standard deviation for 10.0microgL(-1) antimony was 3.56% (n=11) and the sampling rate was 15 samples h(-1). Blank signal was reduced by the purification of reagents and the interference from transition metal ions was eliminated by the addition of L-cysteine into samples. The method was applied to the determination of antimony in environmental samples with satisfactory results. PMID:20441930

  3. Comparing Statewide Economic Impacts of New Generation from Wind, Coal, and Natural Gas in Arizona, Colorado, and Michigan

    SciTech Connect

    Tegen, S.

    2006-05-01

    With increasing concerns about energy independence, job outsourcing, and risks of global climate change, it is important for policy makers to understand all impacts from their decisions about energy resources. This paper assesses one aspect of the impacts: direct economic effects. The paper compares impacts to states from equivalent new electrical generation from wind, natural gas, and coal. Economic impacts include materials and labor for construction, operations, maintenance, fuel extraction, and fuel transport, as well as project financing, property tax, and landowner revenues. We examine spending on plant construction during construction years, in addition to all other operational expenditures over a 20-year span. Initial results indicate that adding new wind power can be more economically effective than adding new gas or coal power and that a higher percentage of dollars spent on coal and gas will leave the state. For this report, we interviewed industry representatives and energy experts, in addition to consulting government documents, models, and existing literature. The methodology for this research can be adapted to other contexts for determining economic effects of new power generation in other states and regions.

  4. Effect of gas heating on the generation of an ultrashort avalanche electron beam in the pulse-periodic regime

    NASA Astrophysics Data System (ADS)

    Baksht, E. Kh.; Burachenko, A. G.; Lomaev, M. I.; Sorokin, D. A.; Tarasenko, V. F.

    2015-07-01

    The generation of an ultrashort avalanche electron beam (UAEB) in nitrogen in the pulse-periodic regime is investigated. The gas temperature in the discharge gap of the atmospheric-pressure nitrogen is measured from the intensity distribution of unresolved rotational transitions ( C 3Π u , v' = 0) → ( B 3Π g , v″ = 0) in the nitrogen molecule for an excitation pulse repetition rate of 2 kHz. It is shown that an increase in the UAEB current amplitude in the pulse-periodic regime is due to gas heating by a series of previous pulses, which leads to an increase in the reduced electric field strength as a result of a decrease in the gas density in the zone of the discharge formation. It is found that in the pulse-periodic regime and the formation of the diffuse discharge, the number of electrons in the beam increases by several times for a nitrogen pressure of 9 × 103 Pa. The dependences of the number of electrons in the UAEB on the time of operation of the generator are considered.

  5. Comparing Statewide Economic Impacts of New Generation from Wind, Coal, and Natural Gas in Arizona, Colorado, and Michigan: Preprint

    SciTech Connect

    Tegen, S.

    2005-08-01

    With increasing concerns about energy independence, job outsourcing, and risks of global climate change, it is important for policy makers to understand all impacts from their decisions about energy resources. This paper assesses one aspect of the impacts: direct economic effects. The paper compares impacts to states from equivalent new electrical generation from wind, natural gas, and coal. Economic impacts include materials and labor for construction, operations, maintenance, fuel extraction, and fuel transport, as well as project financing, property tax, and landowner revenues. We examine spending on plant construction during construction years, in addition to all other operational expenditures over a 20-year span. Initial results indicate that adding new wind power can be more economically effective than adding new gas or coal power, and that a higher percentage of dollars spent on coal and gas will leave the state. For this report, we interviewed industry representatives and energy experts, in addition to consulting government documents, models, and existing literature. The methodology for this research can be adapted to other contexts for determining economic effects of new power generation in other states and regions.

  6. Impact study on the use of biomass-derived fuels in gas turbines for power generation

    SciTech Connect

    Moses, C A; Bernstein, H

    1994-01-01

    This report evaluates the properties of fuels derived from biomass, both gaseous and liquid, against the fuel requirements of gas turbine systems for gernating electrical power. The report attempts to be quantitative rather than merely qualitative to establish the significant variations in the properties of biomass fuels from those of conventional fuels. Three general categories are covered: performance, durability, and storage and handling.

  7. Role of fluctuations in instability generation in gas-solid suspensions

    NASA Astrophysics Data System (ADS)

    Subramaniam, Shankar; Mehrabadi, Mohammad; Kolakaluri, Ravi; Tenneti, Sudheer

    2013-11-01

    Stability analysis of gas-solid suspensions using kinetic theory (Koch, Phys. Fluids, 1990) relies on a number density function (NDF) that is based on the canonical (constant number) ensemble. Euler-Lagrange simulations of a model problem are used to show that this approach does not accurately represent the scale-dependent interphase coupling between different realizations of the gas velocity field and fluctuations in the number of particles naturally occurring in fluidized beds. The grand-canonical (or variable number) ensemble is better suited to representing this coupling, and it is shown how the NDF can be related to this ensemble. The evolution of the grand-canonical NDF then leads to instabilities and growth of spatial fluctuations in the number density of a homogeneous suspension. This analysis leads to a different explanation for the growth of instabilities in homogeneous gas-solid suspensions that does not require perturbations in the average number density. Rather it is shown that the interaction of different realizations of the gas velocity field with individual realizations of the particle field leads to the growth of instabilities due to the dependence of drag on local volume fraction in each realization, that is extracted from particle-resolved DNS data. This work is partially supported by NSF CBET 1134500.

  8. Analysis of Indirect Emissions Benefits of Wind, Landfill Gas, and Municipal Solid Waste Generation

    EPA Science Inventory

    Techniques are introduced to calculate the hourly indirect emissions benefits of three types of green power resources: wind energy, municipal solid waste (MSW) combustion, and landfill gas (LFG) combustion. These techniques are applied to each of the U.S. EPA's eGRID subregions i...

  9. The effect of exercise and rest duration on the generation of venous gas bubbles at altitude

    NASA Technical Reports Server (NTRS)

    Dervay, Joseph P.; Powell, Michael R.; Butler, Bruce; Fife, Caroline E.

    2002-01-01

    BACKGROUND: Decompression, as occurs with aviators and astronauts undergoing high altitude operations or with deep-sea divers returning to surface, can cause gas bubbles to form within the organism. Pressure changes to evoke bubble formation in vivo during depressurization are several orders of magnitude less than those required for gas phase formation in vitro in quiescent liquids. Preformed micronuclei acting as "seeds" have been proposed, dating back to the 1940's. These tissue gas micronuclei have been attributed to a minute gas phase located in hydrophobic cavities, surfactant-stabilized microbubbles, or arising from musculoskeletal activity. The lifetimes of these micronuclei have been presumed to be from a few minutes to several weeks. HYPOTHESIS: The greatest incidence of venous gas emboli (VGE) will be detected by precordial Doppler ultrasound with depressurization immediately following lower extremity exercise, with progressively reduced levels of VGE observed as the interval from exercise to depressurization lengthens. METHODS: In a blinded cross-over design, 20 individuals (15 men, 5 women) at sea level exercised by performing knee-bend squats (150 knee flexes over 10 min, 235-kcal x h(-1)) either at the beginning, middle, or end of a 2-h chair-rest period without an oxygen prebreathe. Seated subjects were then depressurized to 6.2 psia (6,706 m or 22,000 ft altitude equivalent) for 120 min with no exercise performed at altitude. RESULTS: Of the 20 subjects with VGE in the pulmonary artery, 10 demonstrated a greater incidence of bubbles with exercise performed just prior to depressurization, compared with decreasing bubble grades and incidence as the interval of rest increased prior to depressurization. No decompression illness was reported. CONCLUSIONS: There is a significant increase in decompression-induced bubble formation at 6.2 psia when lower extremity exercise is performed just prior to depressurization as compared with longer rest intervals

  10. Development of traceable precision dynamic dilution method to generate dimethyl sulphide gas mixtures at sub-nanomole per mole levels for ambient measurement.

    PubMed

    Kim, Mi Eon; Kim, Yong Doo; Kang, Ji Hwan; Heo, Gwi Suk; Lee, Dong Soo; Lee, Sangil

    2016-04-01

    Dimethyl sulphide (DMS) is an important compound in global atmospheric chemistry and climate change. Traceable international standards are essential for measuring accurately the long-term global trend in ambient DMS. However, developing accurate gas standards for sub-nanomole per mole (nmol/mol) mole fractions of DMS in a cylinder is challenging, because DMS is reactive and unstable. In this study, a dynamic dilution method that is traceable and precise was developed to generate sub-nmol/mol DMS gas mixtures with a dynamic dilution system based on sonic nozzles and a long-term (>5 years) stable 10 μmol/mol parent DMS primary standard gas mixtures (PSMs). The dynamic dilution system was calibrated with traceable methane PSMs, and its estimated dilution factors were used to calculate the mole fractions of the dynamically generated DMS gas mixtures. A dynamically generated DMS gas mixture and a 6 nmol/mol DMS PSM were analysed against each other by gas chromatography with flame-ionisation detection (GC/FID) to evaluate the dilution system. The mole fractions of the dynamically generated DMS gas mixture determined against a DMS PSM and calculated with the dilution factor agreed within 1% at 6 nmol/mol. In addition, the dynamically generated DMS gas mixtures at various mole fractions between 0.4 and 11.7 nmol/mol were analysed by GC/FID and evaluated for their linearity. The analytically determined mole fractions showed good linearity with the mole fractions calculated with the dilution factors. Results showed that the dynamic dilution method generates DMS gas mixtures ranging between 0.4 nmol/mol and 12 nmol/mol with relative expanded uncertainties of less than 2%. Therefore, the newly developed dynamic dilution method is a promising reference method for generating sub-nmol/mol DMS gas standards for accurate ambient measurements. PMID:26838438

  11. Ionization effects in the generation of wake-fields by ultra-high contrast femtosecond laser pulses in argon gas

    SciTech Connect

    Makito, K.; Shin, J.-H.; Zhidkov, A.; Hosokai, T.; Masuda, S.; Kodama, R.

    2012-10-15

    Difference in mechanisms of wake-field generation and electron self-injection by high contrast femtosecond laser pulses in an initially neutral Argon gas and in pre-ionized plasma without ionization is studied via 2D particle-in-cell simulations including optical ionization of the media. For shorter laser pulses, 40 fs, ionization results only in an increase of the charge of accelerated electrons by factor of {approx}3 with qualitatively the same energy distribution. For longer pulses, 80 fs, a more stable wake field structure is observed in the neutral gas with the maximal energy of the accelerated electrons exceeding that in the fixed density plasma. In higher density Argon, an ionizing laser pulse converts itself to a complex system of solitons at a self-induced, critical density ramp.

  12. Generation and Characterization of a Distonic Biradical Anion Formed from an Enediynone Prodrug in the Gas Phase

    NASA Astrophysics Data System (ADS)

    Yang, Linan; Bekele, Tefsit; Lipton, Mark A.; Kenttämaa, Hilkka I.

    2013-04-01

    A negatively charged biradical intermediate was successfully generated in the gas phase via cyclization of the deprotonated bicyclo[8.3.0]trideca-12-ene-2,7-diyn-1-one precursor. The inherent negative charge of this biradical allows its characterization via collision-activated dissociation and reactions with a variety of neutral substrates in an FT-ICR mass spectrometer. Although the biradical is unreactive toward reagents that usually react rapidly with positively charged biradicals, such as dimethyl disulfide, it reacts with the halogen-containing substrates carbon tetrachloride, carbon tetrabromide, and bromotrichloromethane via bromine or chlorine atom abstraction, which supports its biradical structure. The results presented in this study indicate that cyclizations commonly used in solution to form biradical intermediates from enediyne compounds may also occur in the gas phase. [Figure not available: see fulltext.

  13. Generation and Characterization of a Distonic Biradical Anion Formed from an Enediynone Prodrug in the Gas Phase

    PubMed Central

    Yang, Linan; Bekele, Tefsit; Lipton, Mark A.

    2013-01-01

    A negatively charged biradical intermediate was successfully generated in the gas phase via cyclization of the deprotonated bicyclo[8.3.0]trideca-12-ene-2,7-diyn-1-one precursor. The inherent negative charge of this biradical allows its characterization via collision-activated dissociation and reactions with a variety of neutral substrates in an FT-ICR mass spectrometer. Although the biradical is unreactive toward reagents that usually react rapidly with positively charged biradicals, such as dimethyl disulfide, it reacts with the halogen-containing substrates carbon tetrachloride, carbon tetrabromide and bromotrichloromethane via bromine or chlorine atom abstraction, which supports its biradical structure. The results presented in this study indicate that cyclizations commonly used in solution to form biradical intermediates from enediyne compounds may also occur in the gas phase. PMID:23512422

  14. Status and integration of the gas generation studies performed for the Hydrogen Safety Program. FY 1993, Annual report

    SciTech Connect

    Strachan, D.M.

    1994-04-01

    This document represents the second in a series of documents in which information is summarized and integrated on the chemical mechanisms for gas generation from simulated wastes that mimic the nuclear waste in Tank 241-SY. Over the past year the reliability of the instrumentation that has been installed on Tank 101-SY has been increased dramatically. Gases composed of H{sub 2}, N{sub 2}O, N{sub 2}, and NH{sub 3} are continuously released at low levels and also periodically released from the waste stored in this tank such that the lower flammability limit of 4% H{sub 2} is sometimes exceeded. To better understand the reasons for this phenomenon and with the goal of mitigating the potential safety problem associated with the flammability, instrumentation has been installed on the tank and studies have been carried out to understand the mechanism by which these gases are generated. It is worthwhile to annually summarize this information in a single document, to integrate the information, and to highlight the remaining open questions surrounding the mechanism of gas generation. This is the goal of this document. Information on simulated wastes under thermal and radiation conditions has been collected from work performed at Argonne National Laboratory, Georgia Institute of Technology, and Pacific Northwest Laboratory; this report attempts to correlate the simulated data with that of actual tank waste. This document is lengthier than the former report because so much more information was available this year.

  15. Generating Aromatics From CO2 on Mars or Natural Gas on Earth

    NASA Technical Reports Server (NTRS)

    Muscatello, Anthony C.; Zubrin, Robert; Berggren, Mark

    2006-01-01

    Methane to aromatics on Mars ( METAMARS ) is the name of a process originally intended as a means of converting Martian atmospheric carbon dioxide to aromatic hydrocarbons and oxygen, which would be used as propellants for spacecraft to return to Earth. The process has been demonstrated on Earth on a laboratory scale. A truncated version of the process could be used on Earth to convert natural gas to aromatic hydrocarbon liquids. The greater (relative to natural gas) density of aromatic hydrocarbon liquids makes it more economically feasible to ship them to distant markets. Hence, this process makes it feasible to exploit some reserves of natural gas that, heretofore, have been considered as being "stranded" too far from markets to be of economic value. In the full version of METAMARS, carbon dioxide is frozen out of the atmosphere and fed to a Sabatier reactor along with hydrogen (which, on Mars, would have been brought from Earth). In the Sabatier reactor, these feedstocks are converted to methane and water. The water is condensed and electrolyzed to oxygen (which is liquefied) and hydrogen (which is recycled to the Sabatier reactor). The methane is sent to an aromatization reactor, wherein, over a molybdenum-on-zeolite catalyst at a temperature 700 C, it is partially converted into aromatic hydrocarbons (specifically, benzene, toluene, and naphthalene) along with hydrogen. The aromatics are collected by freezing, while unreacted methane and hydrogen are separated by a membrane. Most of the hydrogen is recycled to the Sabatier reactor, while the methane and a small portion of the hydrogen are recycled to the aromatization reactor. The partial recycle of hydrogen to the aromatization reactor greatly increases the catalyst lifetime and eases its regeneration by preventing the formation of graphitic carbon, which could damage the catalyst. (Moreover, if graphitic carbon were allowed to form, it would be necessary to use oxygen to remove it.) Because the aromatics

  16. Addressing the workforce pipeline challenge

    SciTech Connect

    Leonard Bond; Kevin Kostelnik; Richard Holman

    2006-11-01

    A secure and affordable energy supply is essential for achieving U.S. national security, in continuing U.S. prosperity and in laying the foundations to enable future economic growth. To meet this goal the next generation energy workforce in the U.S., in particular those needed to support instrumentation, controls and advanced operations and maintenance, is a critical element. The workforce is aging and a new workforce pipeline, to support both current generation and new build has yet to be established. The paper reviews the challenges and some actions being taken to address this need.

  17. Climate Change Impacts and Greenhouse Gas Mitigation Effects on U.S. Hydropower Generation

    EPA Science Inventory

    Climate change will have potentially significant effects on hydropower generation due to changes in the magnitude and seasonality of river runoff and increases in reservoir evaporation. These physical impacts will in turn have economic consequences through both producer revenues ...

  18. Superior cost-effectiveness in flue gas desulfurization via high-volume, high value byproduct generation

    SciTech Connect

    Ellison, W.

    1998-07-01

    Current worldwide advancements in application and commercial operation of ammonia-base flue gas desulfurization, (FGD), in electric utility service, motivated in part by significant revenues from ammonium sulfate output, are detailed. This new direction in FGD process selection and in the design of flue gas cleaning installations achieves major performance advancements herein reviewed. Attractive cost effectiveness, achieved in the face of substantial capital cost, is quantified. Favorable process economics, superior to that of all available alternatives for high-capacity, high-sulfur, powerplant service, is made possible through substantial value added in conversion of ammonia reagent consumed to agglomerated byproduct, principally ammonium sulfate. This low-nitrogen-content compound, the poor man's fertilizer of times past, is now in great and growing demand for use as sulfur blending stock in worldwide, commercial NPKS, (nitrogen/phosphorus/ potassium/sulfur), chemical fertilizer manufacture.

  19. Resonant third harmonic generation of KrF laser in Ar gas.

    PubMed

    Rakowski, R; Barna, A; Suta, T; Bohus, J; Földes, I B; Szatmári, S; Mikołajczyk, J; Bartnik, A; Fiedorowicz, H; Verona, C; Verona Rinati, G; Margarone, D; Nowak, T; Rosiński, M; Ryć, L

    2014-12-01

    Investigations of emission of harmonics from argon gas jet irradiated by 700 fs, 5 mJ pulses from a KrF laser are presented. Harmonics conversion was optimized by varying the experimental geometry and the nozzle size. For the collection of the harmonic radiation silicon and solar-blind diamond semiconductor detectors equipped with charge preamplifiers were applied. The possibility of using a single-crystal CVD diamond detector for separate measurement of the 3rd harmonic in the presence of a strong pumping radiation was explored. Our experiments show that the earlier suggested 0.7% conversion efficiency can really be obtained, but only in the case when phase matching is optimized with an elongated gas target length corresponding to the length of coherence. PMID:25554270

  20. Development of the next generation medium-duty natural gas engine

    SciTech Connect

    Podnar, D.J.; Kubesh, J.T.

    2000-02-28

    This report summarizes the work done under this subcontract in the areas of System Design, System Fabrication, and Experimental Program. The report contains the details of the engine development process for achieving throttleless stratified charge spark ignition (SI) engine operation as well as advanced turbocharging strategies. Engine test results showing the potential of the direct-injection stratified charge combustion strategy for increasing part-load engine efficiency on a John Deere 8.1-liter natural gas engine are also included in this report. In addition, steady state and step transient engine data are presented that quantify the performance of a variable geometry turbocharger (VGT) as well as a modified waste-gated turbocharger on the engine. The benefits of the technologies investigated during this project will be realized in the form of increased drive-cycle efficiency to diesel-like levels, while retaining the low emissions characteristics of a lean-burn natural gas engine.