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

    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.

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

    DOEpatents

    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.

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

    PubMed

    Hertwich, Edgar G

    2013-09-03

    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.

  6. 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.

  7. 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.

  8. Modelling gas generation for landfill.

    PubMed

    Chakma, Sumedha; Mathur, Shashi

    2016-09-27

    A methodology was developed to predict the optimum long-term spatial and temporal generation of landfill gases such as methane, carbon dioxide, ammonia, and hydrogen sulphide on post-closure landfill. The model incorporated the chemical and the biochemical processes responsible for the degradation of the municipal solid waste. The developed model also takes into account the effects of heterogeneity with different layers as observed at the site of landfills' morphology. The important parameters for gas generation due to biodegradation such as temperature, pH, and moisture content were incorporated. The maximum and the minimum generations of methane and hydrogen sulphide were observed. The rate of gas generation was found almost same throughout the depth after 30 years of landfill closure. The proposed model would be very useful for landfill engineering in the mining landfill gas and proper design for landfill gas management systems.

  9. Oxygen gas generator and method of manufacturing the gas generator

    SciTech Connect

    Marion, F.A.

    1981-12-01

    A gas generator is capable of being stored in a stable form for long periods of time without deteriorating in quality. The gas generator provides a substantial amount of gases, and particularly oxygen, carbon monoxide or carbon dioxide without producing any harmful or hazardous chemicals. The gas generator includes in some embodiments a minimum of fuel so that a maximum amount of oxygen in the generator is capable of being liberated. The oxygen is liberated by the combustion of a fuel at localized positions in a refractory binder, which has the property of preventing the salt residue from becoming molten and the oxidizer from flowing and thereby preventing the combustion from becoming extinguished. The gas generator includes a suitable refractory material (such as clay) as a binder, a suitable oxidizer such as chlorate and a fuel having properties of combusting with oxygen liberated by the oxidizer and having a granular construction and having relatively poor thermal conductivity through the granules to provide the combustion at localized positions in the refractory material. The fuel may constitute a plant by-product having a cellular structure and a high compression strength. The fuel may specifically constitute dried plant life such as corn cobs. The gas generator is formed by mixing the refractory material, the fuel and the oxidizer without the addition of any water and then compressing the mixture into a suitable form such as briquettes.

  10. 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.

  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. PRESAGE: Protecting Structured Address Generation against Soft Errors

    SciTech Connect

    Sharma, Vishal C.; Gopalakrishnan, Ganesh; Krishnamoorthy, Sriram

    2016-12-28

    Modern computer scaling trends in pursuit of larger component counts and power efficiency have, unfortunately, lead to less reliable hardware and consequently soft errors escaping into application data ("silent data corruptions"). Techniques to enhance system resilience hinge on the availability of efficient error detectors that have high detection rates, low false positive rates, and lower computational overhead. Unfortunately, efficient detectors to detect faults during address generation have not been widely researched (especially in the context of indexing large arrays). We present a novel lightweight compiler-driven technique called PRESAGE for detecting bit-flips affecting structured address computations. A key insight underlying PRESAGE is that any address computation scheme that propagates an already incurred error is better than a scheme that corrupts one particular array access but otherwise (falsely) appears to compute perfectly. Ensuring the propagation of errors allows one to place detectors at loop exit points and helps turn silent corruptions into easily detectable error situations. Our experiments using the PolyBench benchmark suite indicate that PRESAGE-based error detectors have a high error-detection rate while incurring low overheads.

  13. Combustion apparatus and method of generating gas

    SciTech Connect

    Van Berkum, R.A.

    1988-05-31

    A combustion apparatus for converting carbon-based fuels in combustible gas is described comprising: a housing which defines an internal reaction chamber; fuel supply means for supplying fuel to the reaction chamber such that a fuel pile of generally constant configuration is maintained in the reaction chamber; a means for supporting the fuel pile, the fuel pile supporting means being disposed adjacent a bottom of the reaction chamber and permitting the flow of gas therethrough; a gas inlet disposed below the fuel pile supporting means for supplying an oxygen-carrying gas through the supporting means to react chemically with the fuel in the fuel pile to generate the combustible gas; ash removal for removing reaction by-products from adjacent the supporting means; a gas outlet for transporting the generated combustible gas from the housing; and, means for partially combusting the generated combustible gas to inhibit condensation of the vapors from the gas.

  14. 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.

  15. 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

  16. 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.

  17. Photovoltaic energy gas generating apparatus

    SciTech Connect

    Ahuja, O.

    1986-01-21

    This patent describes an apparatus for the recovery and storage of hydrogen, cathode gas, from water. The apparatus consists of: (A) and aquatic float, the float defining: (I) a cathode gas collection chamber, (II) at least one outlet to the collection chamber for withdrawing the collected gas, (III) elongate tubes extending downwardly from the collection chamber and in open communication, (IV) the displacement of the float creating a column of water within each elongate tube, (B) at least one cathode within each elongate tube, the cathodes extending downwardly from the upper ends of the elongate tube to a predetermined level, (C) at least one anode outside the elongate tubes extending downwardly from the float into the water, (D) a photovoltaic panel mounted on the collection chamber and in electrical communication with the cathodes and anodes to electrolyze the water and collect the electrolyzed cathode gas about the cathode within the elongate tubes. The electrolyzed cathode gas rises within the elongate tubes to collect within the collection chamber until the float rises above the predetermined level whereupon the electrolysis is automatically terminated as the cathodes and/or anodes rise above the water.

  18. 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...

  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. 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....

  1. 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.

  2. Fuel cell with storable gas generator

    SciTech Connect

    Iwanciow, B.L.

    1986-12-09

    A system is described for providing gaseous hydrogen and oxygen to a hydrogen/oxygen fuel cell, the combination which comprises: (a) hydrogen/oxygen fuel cell assembly; (b) a hydrogen gas generator having a first heterogeneous mixture comprising lithium borohydride and iron oxide contained therein; (c) a means to initiate the first mixture to generate gaseous hydrogen; (d) a means to feed the gaseous hydrogen to the hydrogen/oxygen fuel cell; (e) an oxygen gas generator having a second heterogeneous mixture comprising sodium chlorate and elemental iron contained therein; (f) a means to initiate the second mixture to generate gaseous oxygen; and (g) a means to feed the gaseous oxygen to the hydrogen/oxygen fuel cell.

  3. Development of a NASA standard gas generator

    NASA Technical Reports Server (NTRS)

    Bement, Laurence J.; Karp, Harold; Schimmel, Morry L.

    1993-01-01

    The goals of the NASA Standard Gas Generator (NSGG) Program are to create a NASA standard gas generating cartridge, characterize its performance, and make it readily available to users. A cartridge within the same envelope as the NASA Standard Initiator (NSI) has the greatest potential use. This potential use is described in viewgraph form. Our approach for NSGG development and qualification was planned to be conducted in several phases. Test methods were developed to evaluate output performance for a variety of potential applications. A feasibility study using modified NSI's was accomplished. Preliminary and final development will be conducted with a delta qualification to evaluate the effects of manufacturing lots and environments. Feasibility study results, feasibility study conclusions, and future plans are presented.

  4. 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...

  5. 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.

  6. 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.

  7. 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

  8. Efficient and Safe Chemical Gas Generators with Nanocomposite Reactive Materials

    DTIC Science & Technology

    2015-11-30

    customized chemical gas generators based on novel energetic materials that will exhibit improved effectiveness, process stability, and fire safety...2015 Approved for Public Release; Distribution Unlimited Final Report: Efficient and Safe Chemical Gas Generators with Nanocomposite Reactive Materials...Building, Room 209 El Paso, TX 79968 -0587 12-Sep-2015 ABSTRACT Final Report: Efficient and Safe Chemical Gas Generators with Nanocomposite Reactive

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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.

  15. 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.

  16. Life-cycle greenhouse gas assessment of Nigerian liquefied natural gas addressing uncertainty.

    PubMed

    Safaei, Amir; Freire, Fausto; Henggeler Antunes, Carlos

    2015-03-17

    Natural gas (NG) has been regarded as a bridge fuel toward renewable sources and is expected to play a greater role in future global energy mix; however, a high degree of uncertainty exists concerning upstream (well-to-tank, WtT) greenhouse gas (GHG) emissions of NG. In this study, a life-cycle (LC) model is built to assess uncertainty in WtT GHG emissions of liquefied NG (LNG) supplied to Europe by Nigeria. The 90% prediction interval of GHG intensity of Nigerian LNG was found to range between 14.9 and 19.3 g CO2 eq/MJ, with a mean value of 16.8 g CO2 eq/MJ. This intensity was estimated considering no venting practice in Nigerian fields. The mean estimation can shift up to 25 g CO2 eq when considering a scenario with a higher rate of venting emissions. A sensitivity analysis of the time horizon to calculate GHG intensity was also performed showing that higher GHG intensity and uncertainty are obtained for shorter time horizons, due to the higher impact factor of methane. The uncertainty calculated for Nigerian LNG, specifically regarding the gap of data for methane emissions, recommends initiatives to measure and report emissions and further LC studies to identify hotspots to reduce the GHG intensity of LNG chains.

  17. 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.

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

    ScienceCinema

    Thomas D'Agostino

    2016-07-12

    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.

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

    ScienceCinema

    Thomas D'Agostino

    2016-07-12

    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.

  20. 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.

  1. 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.

  2. Gas dilution system using critical flow Venturi nozzles for generating primary trace-moisture standards in multiple gas species

    NASA Astrophysics Data System (ADS)

    Amano, Minami; Abe, Hisashi

    2017-02-01

    Gas dilution systems are commonly used to generate calibration gas mixtures for secondary gas standards. However, if a gas dilution system is used to generate gas mixtures for primary trace-moisture standards in multiple gas species, difficulty arises; flow control with relative stability of better than 0.009% is required although the relative uncertainty of the best gas flow meter to date is around 0.3%. In this study, we developed a novel gas dilution system using critical flow Venturi nozzles to address this problem. The developed dilution system can measure and control the flow rates of gases in the range of approximately 0.05 l min-1 to 7 l min-1 (when converted to those measured at 101 325 Pa and 273.15 K) with relative stability of better than 0.007%. Using the dilution system, we developed a magnetic suspension balance/diffusion-tube humidity generator capable of generating trace moisture in N2 in the range of approximately 10 nmol mol-1 to 5 µmol mol-1 in amount fraction. The accuracy of the generated trace-moisture standard was verified by measurement with cavity ring-down spectroscopy.

  3. 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.

  4. 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.

  5. 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.

  6. Addressing Factors that Control Near-Surface Gas Hydrate Stability with Time-Series Measurements

    NASA Astrophysics Data System (ADS)

    Lapham, L.; Wilson, R. M.; Chanton, J.; Riedel, M.

    2015-12-01

    Gas hydrates are sensitive to pressure and temperature changes, based on their thermodynamic properties. In nature, this translates to changes in sealevel and/or ocean water temperature fluctuations. When hydrates outcrop the seafloor, however, they could also be sensitive to physical disturbances, such as earthquakes, and microbial processes (such as sulfate reduction and/or methane oxidation), both of which could lead to their dissolution. To address these factors controlling hydrate stability, we will present in situ methane, sulfate, and chloride concentrations over time, in pore-waters of shallow sediments near gas hydrates in seep systems. Datasets presented will include one 4-month time series from the Northern Gulf of Mexico, Mississippi Canyon 118, and two 9-month records from offshore Vancouver Island, Barkley Canyon and Bubbly Gulch at Bullseye Vent. We will address the following questions: Does regional scale oceanography affect methane flux from the hydrate-containing sediments, are microbial processes playing a role in hydrate stability, and what are in situ hydrate dissolution rates? We will also discuss challenges faced with collecting such data, and ways to move forward. We will show that in some systems, methane is nearly saturated within a few cm of the overlying water, thus stabilizing the hydrate. Yet in other systems, methane is undersaturated with respect to methane hydrate which suggests hydrates will dissolve. We will also present laboratory rates of hydrate dissolution to compare to those gained from the field.

  7. 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...

  8. 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...

  9. 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...

  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. 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.

  13. Gas generation results and venting study for transuranic waste drums

    SciTech Connect

    Kazanjian, A.R.; Arnold, P.M.; Simmons, W.C.; D'Amico, E.L.

    1985-09-23

    Sixteen waste drums, containing six categories of plutonium-contaminated waste, were monitored for venting and gas generation for six months. The venting devices tested appeared adequate to relieve pressure and prevent hydrogen accumulation. Most of the gas generation, primarily H2 and CO2, was due to radiolytic decomposition of the hydrogenous wastes. Comparison of the gas yields with those obtained previously in laboratory tests showed very reasonable agreement with few exceptions.

  14. 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.

  15. 76 FR 58846 - Final Interim Staff Guidance: Review of Evaluation To Address Gas Accumulation Issues in Safety...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-22

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Final Interim Staff Guidance: Review of Evaluation To Address Gas Accumulation Issues in Safety.... Nuclear Regulatory Commission (NRC) staff is issuing its Final Interim Staff Guidance (ISG)...

  16. Dynamics of exhaust gas generated by arc extinction

    NASA Astrophysics Data System (ADS)

    Hayashi, Yasushi; Watanabe, Masato; Okino, Akitoshi; Hotta, Eiki

    2001-11-01

    We report an analytical study on hot gas exhaust process of a SF6 gas circuit breaker (GCB), after current interruption. The behavior of the hot gas has been studied based on measured gas temperature and simulation results of gas composition. We also propose a mechanism of interaction between the hot gas and pressure waves, which causes a self-blocking of the exhaust gas. During the heavy current interruption, the flow model suggests that the dielectric strength of the hot gas is affected by the pressure waves that are generated by the hot gas exhaustion. We believe that the results reported in this article provide guidance for the optimum structure of the exhaust chamber for small size GCB, operating at very high interrupting current.

  17. Thermal and radiolytic gas generation from Tank 241-S-102 waste

    SciTech Connect

    King, C.M.; Pederson, L.R.; Bryan, S.A.

    1997-07-01

    This report summarizes progress in evaluating thermal and radiolytic rate parameters for flammable gas generation in Hanford single-shell tank wastes based on the results of laboratory tests using actual waste from Tank 241-S-102 (S-102). Work described in this report was conducted at Pacific Northwest National Laboratory (PNNL) for the Flammable Gas Safety Project, whose purpose is to develop information to support Fluor Daniel Hanford (FDH) and its Project Management Hanford Contract (PHMC) subcontractors in their efforts to ensure the safe interim storage of wastes at the Hanford Site. This work is related to gas generation studies being performed at Georgia Institute of Technology (GIT) under subcontract to PNNL, using simulated wastes, and to studies being performed at Numatec Hanford Corporation (formerly Westinghouse Hanford Company) using actual wastes. The results of gas generation from Tank S-102 waste under thermal and radiolytic conditions are described in this report. The accurate measurement of gas generation rates in actual waste from highly radioactive waste tanks is needed to assess the potential for producing and storing flammable gases within the waste tanks. This report addresses the gas generation capacity of the waste from Tank S-102, a waste tank listed as high priority by the Flammable Gas Safety Program due to its potential for flammable gas accumulation above the flammability limit.

  18. 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.

  19. 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.

  20. 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.

  1. 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...

  2. 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 ...

  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. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...: (a) Produce an inert gas containing less than 5% oxygen by volume; (b) Have a device to continuously sample the discharge of the generator for oxygen content; and (c) Have an audible and visual alarm in the cargo control station that alarms when the inert gas contains 5% or more oxygen by volume....

  5. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...: (a) Produce an inert gas containing less than 5% oxygen by volume; (b) Have a device to continuously sample the discharge of the generator for oxygen content; and (c) Have an audible and visual alarm in the cargo control station that alarms when the inert gas contains 5% or more oxygen by volume....

  6. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...: (a) Produce an inert gas containing less than 5% oxygen by volume; (b) Have a device to continuously sample the discharge of the generator for oxygen content; and (c) Have an audible and visual alarm in the cargo control station that alarms when the inert gas contains 5% or more oxygen by volume....

  7. 46 CFR 154.906 - Inert gas generators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...: (a) Produce an inert gas containing less than 5% oxygen by volume; (b) Have a device to continuously sample the discharge of the generator for oxygen content; and (c) Have an audible and visual alarm in the cargo control station that alarms when the inert gas contains 5% or more oxygen by volume....

  8. Applications for Solid Propellant Cool Gas Generator Technology

    NASA Astrophysics Data System (ADS)

    van der List, M.; van Vliet, L. D.; Sanders, H. M.; Put, P. A. G.; Elst, J. W. E. C.

    2004-10-01

    In 2002 and 2003, Bradford Engineering B.V. conducted, in corporation with the Dutch research institute TNO Prins Maurits Laboratory (PML) a SME study for ESA-ESTEC for the identification of spaceflight applications and on-ground demonstration of Solid Propellant Cool Gas Generator (SPCGG) technology. This innovative technology has been developed by TNO-PML while Bradford Engineering also brought in its experience in spaceflight hardware development and manufacturing. The Solid Propellant Cool Gas Generator (SPCGG) technology allows for pure gas generation at ambient temperatures, as opposed to conventional solid propellant gas generators. This makes the SPCGG technology interesting for a wide range of terrestrial spaceflight applications. During the first part of the study, a variety of potential applications have been identified and three applications were selected for a more detailed quantitative study. In the third phase a ground demonstration was performed successfully for a cold gas propulsion system application. During the actual demonstration test, 10 cool gas generators were mounted and all operated successfully in sequence, demonstrating good repeatability of the produced amount of gas and pressure.

  9. Radiolytic Gas Generation in Crystalline Silicotitanate Slurries

    SciTech Connect

    WALKER, DARREL

    2004-03-15

    This study measured the impact of crystalline silicotitanate (CST) solids on the rate of formation and composition of radiolytically generated gases in simulated Savannah River Site liquid waste. The tests used IONSIV (TM) IE-911 (UOP LLC, Molecular Sieves Division, Des Planes, IL), the engineered form of CST.

  10. Gas Generation of Heated PBX 9502

    SciTech Connect

    Holmes, Matthew David; Parker, Gary Robert

    2016-10-07

    Uniaxially pressed samples of PBX 9502 were heated until self-ignition (cookoff) in order to collect pressure and temperature data relevant for model development. Samples were sealed inside a small gas-tight vessel, but were mechanically unconfined. Long-duration static pressure rise, as well as dynamic pressure rise during the cookoff event, were recorded. Time-lapse photography of the sample was used to measure the thermal expansion of the sample as a function of time and temperature. High-speed videography qualitatively characterized the mechanical behavior and failure mechanisms at the time of cookoff. These results provide valuable input to modeling efforts, in order to improve the ability to predict pressure output during cookoff as well as the effect of pressure on time-toignition.

  11. 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.

  12. 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

  13. 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.

  14. 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 .

  15. 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...

  16. 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.

  17. Gas generation matrix depletion quality assurance project plan

    SciTech Connect

    1998-05-01

    The Los Alamos National Laboratory (LANL) is to provide the necessary expertise, experience, equipment and instrumentation, and management structure to: Conduct the matrix depletion experiments using simulated waste for quantifying matrix depletion effects; and Conduct experiments on 60 cylinders containing simulated TRU waste to determine the effects of matrix depletion on gas generation for transportation. All work for the Gas Generation Matrix Depletion (GGMD) experiment is performed according to the quality objectives established in the test plan and under this Quality Assurance Project Plan (QAPjP).

  18. 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

    2014-08-05

    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.

  19. 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

  20. EPA Takes First Steps to Address Greenhouse Gas Emissions from Aircraft

    EPA Pesticide Factsheets

    WASHINGTON - The U.S. Environmental Protection Agency (EPA) is proposing to find under the Clean Air Act that greenhouse gas (GHG) emissions from commercial aircraft contribute to the pollution that causes climate change endangering the health and welfare

  1. Thermal Analysis and Testing of Fastrac Gas Generator Design

    NASA Technical Reports Server (NTRS)

    Nguyen, H.

    1998-01-01

    The Fastrac Engine is being developed by the Marshall Space Flight Center (MSFC) to help meet the goal of substantially reducing the cost of access to space. This engine relies on a simple gas-generator cycle, which burns a small amount of RP-1 and oxygen to provide gas to drive the turbine and then exhausts the spent fuel. The Fastrac program envisions a combination of analysis, design and hot-fire evaluation testing. This paper provides the supporting thermal analysis of the gas generator design. In order to ensure that the design objectives were met, the evaluation tests have started on a component level and a total of 15 tests of different durations were completed to date at MSFC. The correlated thermal model results will also be compared against hot-fire thermocouple data gathered.

  2. 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.

  3. 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.

  4. 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.

  5. GE power generation technology challenges for advanced gas turbines

    SciTech Connect

    Cook, C.S.; Nourse, J.G.

    1993-11-01

    The GE Utility ATS is a large gas turbine, derived from proven GEPG designs and integrated GEAE technology, that utilizes a new turbine cooling system and incorporates advanced materials. This system has the potential to achieve ATS objectives for a utility sized machine. Combined with use of advanced Thermal Barrier Coatings (TBC`s), the new cooling system will allow higher firing temperatures and improved cycle efficiency that represents a significant improvement over currently available machines. Developing advances in gas turbine efficiency and emissions is an ongoing process at GEPG. The third generation, ``F`` class, of utility gas turbines offers net combined cycle efficiencies in the 55% range, with NO{sub x} programs in place to reduce emissions to less than 10 ppM. The gas turbines have firing temperatures of 2350{degree}F, and pressure ratios of 15 to 1. The turbine components are cooled by air extracted from the cycle at various stages of the compressor. The heat recovery cycle is a three pressure steam system, with reheat. Throttle conditions are nominally 1400 psi and 1000{degree}F reheat. As part of GEPG`s ongoing advanced power generation system development program, it is expected that a gas fired advanced turbine system providing 300 MW power output greater than 58% net efficiency and < 10 ppM NO{sub x} will be defined. The new turbine cooling system developed with technology support from the ATS program will achieve system net efficiency levels in excess of 60%.

  6. EPA Takes First Steps to Address Greenhouse Gas Emissions from Aircraft

    EPA Pesticide Factsheets

    (06/10/15 -ATLANTA) - The U.S. Environmental Protection Agency (EPA) is proposing to find under the Clean Air Act that greenhouse gas (GHG) emissions from commercial aircraft contribute to the pollution that causes climate change endangering the hea

  7. 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.

  8. 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.

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

    SciTech Connect

    Marnay, Chris; Stadler, Michael; Lipman, Tim; Lai, Judy; Cardoso, Goncalo; Megel, Olivier

    2009-09-01

    The motivation and objective of this research is to determine the role of distributed generation (DG) in greenhouse gas reductions by: (1) applying the Distributed Energy Resources Customer Adoption Model (DER-CAM); (2) using the California Commercial End-Use Survey (CEUS) database for commercial buildings; (3) selecting buildings with electric peak loads between 100 kW and 5 MW; (4) considering fuel cells, micro-turbines, internal combustion engines, gas turbines with waste heat utilization, solar thermal, and PV; (5) testing of different policy instruments, e.g. feed-in tariff or investment subsidies.

  10. Hydrogen Peroxide Gas Generator Cycle with a Reciprocating Pump

    SciTech Connect

    Whitehead, J C

    2002-06-11

    A four-chamber piston pump is powered by decomposed 85% hydrogen peroxide. The performance envelope of the evolving 400 gram pump has been expanded to 172 cc/s water flow at discharge pressures near 5 MPa. A gas generator cycle system using the pump has been tested under similar conditions of pressure and flow. The powerhead gas is derived from a small fraction of the pumped hydrogen peroxide, and the system starts from tank pressures as low as 0.2 MPa. The effects of steam condensation on performance have been evaluated.

  11. Analysis of hypercube cache performance using address traces generated by TRAPEDS

    NASA Technical Reports Server (NTRS)

    Stunkel, Craig B.; Fuchs, W. Kent

    1989-01-01

    The authors utilize a recently developed software method of capturing and analyzing address traces, known as TRAPEDS (TRAce Producing Execution Driven Simulation), to provide address traces for cache performance evaluation on a hypercube multicomputer. Utilizing TRAPEDS user code traces obtained from the implementations of several parallel algorithms on the Intel iPSC/2 hypercube, the authors simulate the cache performance effects of changing cache size, line size, and set associativity. Particular attention is devoted to the effect on cache performance of changing the dimension of the hypercube for a particular program and to the variation in cache statistics among the nodes of the hypercube.

  12. 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…

  13. 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

  14. 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.

  15. 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

  16. Specifying the Concept of Future Generations for Addressing Issues Related to High-Level Radioactive Waste.

    PubMed

    Kermisch, Celine

    2016-12-01

    The nuclear community frequently refers to the concept of "future generations" when discussing the management of high-level radioactive waste. However, this notion is generally not defined. In this context, we have to assume a wide definition of the concept of future generations, conceived as people who will live after the contemporary people are dead. This definition embraces thus each generation following ours, without any restriction in time. The aim of this paper is to show that, in the debate about nuclear waste, this broad notion should be further specified and to clarify the related implications for nuclear waste management policies. Therefore, we provide an ethical analysis of different management strategies for high-level waste in the light of two principles, protection of future generations-based on safety and security-and respect for their choice. This analysis shows that high-level waste management options have different ethical impacts across future generations, depending on whether the memory of the waste and its location is lost, or not. We suggest taking this distinction into account by introducing the notions of "close future generations" and "remote future generations", which has important implications on nuclear waste management policies insofar as it stresses that a retrievable disposal has fewer benefits than usually assumed.

  17. Oxygen rich gas generator design and performance analysis

    NASA Technical Reports Server (NTRS)

    Gloyer, P. W.; Knuth, W. H.; Crawford, R. A.

    1993-01-01

    The present oxygen-rich combustion research investigates oxygen gas generator concepts. The theoretical and modeling aspects of a selected concept are presented, together with a refined concept resulting from the findings of the study. This investigation examined a counter-flow gas generator design for O2/H2 mass ratios of 100-200, featuring a near-stoichiometric combustion zone followed by downstream mixing. The critical technologies required to develop a performance model are analyzed and include the following: (1) oxygen flow boiling; (2) two-phase oxygen flow heat transfer; (3) film-cooling in the combustion zone; (4) oxygen-rich combustion with hydrogen; and (5) mixing and dilution.

  18. Generation of local concentration gradients by gas-liquid contacting.

    PubMed

    de Jong, Jorrit; Verheijden, Pascal W; Lammertink, Rob G H; Wessling, Matthias

    2008-05-01

    We present a generic concept to create local concentration gradients, based on the absorption of gases or vapors in a liquid. A multilayer microfluidic device with crossing gas and liquid channels is fabricated by micromilling and used to generate multiple gas-liquid contacting regions, separated by a hydrophobic membrane. Each crossing can acts as both a microdosing and microstripping region. Furthermore, the liquid and gas flow rate can be controlled independently of each other. The focus of this conceptual article is on the generation of pH gradients, by locally supplying acidic or basic gases/vapors, such as carbon dioxide, hydrochloric acid, and ammonia, visualized by pH-sensitive dyes. Stationary and moving gradients are presented in devices with 500-microm channel width, depths of 200-400 microm, and lengths of multiple centimeters. It is shown that the method allows for multiple consecutive switching gradients in a single microchannel. Absorption measurements in a microcontactor with the model system CO2/water are presented to indicate the dependence of gas absorption rate on channel depth and residence time. Achievable concentration ranges are ultimately limited by the solubility of used components. The reported devices are easy to fabricate, and their application is not limited to pH gradients. Two proof of principles are demonstrated to indicate new opportunities: (i) local crystallization of NaCl using HCl vapor and (ii) consecutive reactions of ammonia with copper(II) ions in solution.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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…

  4. 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…

  5. 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.

  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. 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.

  8. 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.

  9. 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.

  10. Release protocol to address DOE moratorium on shipments of waste generated in radiologically controlled areas

    SciTech Connect

    Rathbun, L A; Boothe, G F

    1992-10-01

    On May 17, 1991 the US DOE Office of Waste Operations issued a moratorium on the shipment of hazardous waste from radiologically contaminated or potentially contaminated areas on DOE sites to offsite facilities not licensed for radiological material. This document describes a release protocol generated by Westinghouse Hanford submitted for US DOE approval. Topics considered include designating Radiological Materials Management Areas (RMMAs), classification of wastes, handling of mixed wastes, detection limits.

  11. 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.

  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. 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

  14. 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.

  15. 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

  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; 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. Gas Generation in Radioactive Wastes - MAGGAS Predictive Life Cycle Model

    SciTech Connect

    Streatfield, R.E.; Hebditch, D.J.; Swift, B.T.; Hoch, A.R.; Constable, M.

    2006-07-01

    Gases may form from radioactive waste in quantities posing different potential hazards throughout the waste package life cycle. The latter includes surface storage, transport, placing in an operating repository, storage in the repository prior to backfill, closure and the post-closure stage. Potentially hazardous situations involving gas include fire, flood, dropped packages, blocked package vents and disruption to a sealed repository. The MAGGAS (Magnox Gas generation) model was developed to assess gas formation for safety assessments during all stages of the waste package life cycle. This is a requirement of the U.K. regulatory authorities and Nirex and progress in this context is discussed. The processes represented in the model include: Corrosion, microbial degradation, radiolysis, solid-state diffusion, chemico-physical degradation and pressurisation. The calculation was split into three time periods. First the 'aerobic phase' is used to model the periods of surface storage, transport and repository operations including storage in the repository prior to backfill. The second and third periods were designated 'anaerobic phase 1' and 'anaerobic phase 2' and used to model the waste packages in the post-closure phase of the repository. The various significant gas production processes are modeled in each phase. MAGGAS (currently Version 8) is mounted on an Excel spreadsheet for ease of use and speed, has 22 worksheets and is operated routinely for assessing waste packages (e.g. for ventilation of stores and pressurisation of containers). Ten operational and decommissioning generic nuclear power station waste streams were defined as initial inputs, which included ion exchange materials, sludges and concentrates, fuel element debris, graphite debris, activated components, contaminated items, desiccants and catalysts. (authors)

  5. 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.

  6. Pulsed x-ray generator for commercial gas lasers

    NASA Astrophysics Data System (ADS)

    Bollanti, S.; Bonfigli, F.; Di Lazzaro, P.; Flora, F.; Giordano, G.; Letardi, T.; Murra, D.; Schina, G.; Zheng, C. E.

    2001-10-01

    We have designed and tested a 1-m-long x-ray diode based on innovative plasma cathodes, which exploit commercial spark plugs as electron emitters. Based on the results of a numerical study, we optimized both diode geometry (e.g., the angle between anode and cathode surfaces, the thickness of the Al window) and electrical circuitry (e.g., the capacitance in series to each spark plug, the peak voltage of the anode) of our x-ray generator. The overall result is a simple and efficient circuitry, giving a total diode current in excess of 2.1 kA with a breakdown voltage of 70 kV, which generates a 50 ns rise-time x-ray pulse with a spatially averaged dosage of up to 6×10-4 Gy when using a Pb-wrapped anode. The double-diode x-ray generator was operated for 1.5×106 shots at a repetition rate of up to 30 Hz, and the lifetime test was interrupted without any fault. During the lifetime test, it was not necessary to adjust any working parameter. At the end of the lifetime test, the x-ray emission uniformity was better than 80% along the longitudinal axis. This x-ray generator has a lifetime, reliability, and cost fitting the requirements of industrial users. Among the broad range of potential applications, this x-ray generator is particularly suitable to ionize discharge pumped gas lasers, like TEA CO2 and excimer lasers, including those operated by x-ray triggered discharges.

  7. Decreasing lateral diffusion of photo-generated carriers for light-addressable potentiometric array by using meshed working electrode

    NASA Astrophysics Data System (ADS)

    Chen, Dong; Liu, ShiBin; Yin, ShiMin; Liang, JinTao

    2016-09-01

    Lateral diffusion of photon-generated carriers is a critical factor affecting the signal stability and spatial resolution of light-addressable potentiometric sensor (LAPS) array. LAPS with meshed working electrode for rejecting lateral diffusion is presented. Simulation shows that using meshed working electrode can resist the lateral distribution. In an experiment, the inhibition of lateral distribution and the signal stability was studied. Results showed, using the meshed working electrode, the ability to reject the lateral distribution and the signal stability is obviously enhanced. Research in this paper may help to enhance spatial resolution and detection stability of LAPS.

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

    PubMed

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

    2012-09-01

    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.

  9. 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

  10. Effects of the Fataki campaign: addressing cross-generational sex in Tanzania by mobilizing communities to intervene.

    PubMed

    Kaufman, Michelle R; Mooney, Alyssa; Kamala, Benjamin; Modarres, Najmeh; Karam, Robert; Ng'wanansabi, Deo

    2013-07-01

    The national multimedia "Fataki" campaign aired in Tanzania from 2008 to 2011 with the goal of addressing cross-generational sex (CGS) by mobilizing communities to intervene in CGS relationships. A cross-sectional household survey was used to evaluate the campaign. Logistic regression analysis found a dose-response relationship between campaign exposure and interpersonal communication about CGS, intervening in CGS relationships, and lower CGS engagement among women. No association was found between campaign exposure and current CGS involvement among men, though longer-term data collection may be needed to assess changes in relationship patterns. Findings indicated that engaging in interpersonal communication about CGS was associated with a higher likelihood of actually intervening. Strategies to generate further discussion surrounding CGS and increase impact, such as through community-based components to supplement campaigns, are discussed.

  11. 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.

  12. 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.

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

    DOE PAGES

    Jordan, Amy B.; Stauffer, Philip H.; Knight, Earl E.; ...

    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. 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

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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...

  7. 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.

  8. 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…

  9. Laboratory Studies of Hydrogen Gas Generation Using the Cobalt Chloride Catalyzed Sodium Borohydride-Water Reaction

    DTIC Science & Technology

    2015-07-01

    TECHNICAL REPORT 2082 July 2015 Laboratory Studies of Hydrogen Gas Generation Using the Cobalt Chloride Catalyzed Sodium ...describes experiments to generate hydrogen gas using the cobalt chloride catalyzed sodium borohydride-water reaction. Space and Naval Warfare Systems...to inflate LTAs. Of the metal hydrides, we chose to explore the sodium borohydride chemistry. We chose this chemistry because of its energy density

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

    SciTech Connect

    Unknown

    2001-10-30

    The objectives of this report period were to continue the development of the Gas Generator design, to complete the hardware and ancillary hardware fabrication, and commence the Test Preparations for the testing of the non-polluting unique power turbine drive gas generator. Focus during this report period has been on testing the Gas Generator. Because of unacceptable delays encountered in a previously competitively selected test site, CES initiated a re-competition of our testing program and selected an alternate test site. Following that selection, CES used all available resources to make preparations for testing the 10 Mw Gas Generator at the new testing site facilities of NTS at Saugus, CA. A substantial portion of this report period was devoted to Testing Preparations, i.e. test facility development, cold- flow testing, calibration testing, performing igniter ignition testing, and then commencement of the completely assembled Gas Generator Assembly Testing, in process at this writing.

  11. 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.

  12. 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

  13. 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.

  14. Fuel prices, emission standards, and generation costs for coal vs natural gas power plants.

    PubMed

    Pratson, Lincoln F; Haerer, Drew; Patiño-Echeverri, Dalia

    2013-05-07

    Low natural gas prices and stricter, federal emission regulations are promoting a shift away from coal power plants and toward natural gas plants as the lowest-cost means of generating electricity in the United States. By estimating the cost of electricity generation (COE) for 304 coal and 358 natural gas plants, we show that the economic viability of 9% of current coal capacity is challenged by low natural gas prices, while another 56% would be challenged by the stricter emission regulations. Under the current regulations, coal plants would again become the dominant least-cost generation option should the ratio of average natural gas to coal prices (NG2CP) rise to 1.8 (it was 1.42 in February 2012). If the more stringent emission standards are enforced, however, natural gas plants would remain cost competitive with a majority of coal plants for NG2CPs up to 4.3.

  15. 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.

  16. Numerical solution of moving boundary problem for deposition process in solid fuel gas generator

    NASA Astrophysics Data System (ADS)

    Volokhov, V. M.; Dorofeenko, S. O.; Sharov, M. S.; Toktaliev, P. D.

    2016-11-01

    Moving boundary problem in application to process of depositions formation in gas generator are considered. Gas generator, as a part of fuel preparation system of high-speed vehicle, convert solid fuel into multicomponent multiphase mixture, which further burned down in combustion chamber. Mathematical model of two-phase “gas-solid particles” flow, including Navier-Stokes equations for turbulent flow in gas generator and mass, impulse conservations laws for elementary depositions layer are proposed. Verification of proposed mathematical model for depositions mass in gas generator conditions is done. Further possible improvements of proposed model, based on more detail accounting of particle-wall interaction and wall's surface adhesion properties are analyzed.

  17. Islip axis gas could support Central England power generation

    SciTech Connect

    Oswald, D.H.

    1996-08-05

    The Islip axis is part of a major structural feature in Central England that reaches its culmination about 4 miles north of Oxford. During Mesozoic time this area lay between the relatively stable London platform in the east and the subsiding Worcester basin in the west. Paleozoic rocks, Cambrian to Devonian, underlie the Mesozoic rocks on the London platform, while to the west Permo-Triassic rocks rest on coal measures. The subsurface structure and stratigraphy of the area have been established by many boreholes drilled in the early years of the century for coal and more recently by the British Gas Council exploring for a porous reservoir for gas storage. The paper discusses the reservoir, cap rock, structure, source rock, oil and gas occurrences, and economic potential.

  18. 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.; Max, Michael D.

    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.

  19. Modeling the final phase of landfill gas generation from long-term observations.

    PubMed

    Tintner, Johannes; Kühleitner, Manfred; Binner, Erwin; Brunner, Norbert; Smidt, Ena

    2012-06-01

    For waste management, methane emissions from landfills and their effect on climate change are of serious concern. Current models for biogas generation that focus on the economic use of the landfill gas are usually based on first order chemical reactions (exponential decay), underestimating the long-term emissions of landfills. The presented study concentrated on the curve fitting and the quantification of the gas generation during the final degradation phase under optimal anaerobic conditions. For this purpose the long-term gas generation (240-1,830 days) of different mechanically biologically treated (MBT) waste materials was measured. In this study the late gas generation was modeled by a log-normal distribution curve to gather the maximum gas generation potential. According to the log-normal model the observed gas sum curve leads to higher values than commonly used exponential decay models. The prediction of the final phase of landfill gas generation by a fitting model provides a basis for CO(2) balances in waste management and some information to which extent landfills serve as carbon sink.

  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. Modeling of gas generation from the Barnett Shale, Fort Worth Basin, Texas

    USGS Publications Warehouse

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

    2007-01-01

    The generative gas potential of the Mississippian Barnett Shale in the Fort Worth Basin, Texas, was quantitatively evaluated by sealed gold-tube pyrolysis. Kinetic parameters for gas generation and vitrinite reflectance (Ro) changes were calculated from pyrolysis data and the results used to estimate the amount of gas generated from the Barnett Shale at geologic heating rates. Using derived kinetics for Ro evolution and gas generation, quantities of hydrocarbon gas generated at Ro ??? 1.1% are about 230 L/t (7.4 scf/t) and increase to more that 5800 L/t (186 scf/t) at Ro ??? 2.0% for a sample with an initial total organic carbon content of 5.5% and Ro = 0.44%. The volume of shale gas generated will depend on the organic richness, thickness, and thermal maturity of the shale and also the amount of petroleum that is retained in the shale during migration. Gas that is reservoired in shales appears to be generated from the cracking of kerogen and petroleum that is retained in shales, and that cracking of the retained petroleum starts by Ro ??? 1.1%. This result suggests that the cracking of petroleum retained in source rocks occurs at rates that are faster than what is predicted for conventional siliciclastic and carbonate reservoirs, and that contact of retained petroleum with kerogen and shale mineralogy may be a critical factor in shale-gas generation. Shale-gas systems, together with overburden, can be considered complete petroleum systems, although the processes of petroleum migration, accumulation, and trap formation are different from what is defined for conventional petroleum systems. Copyright ?? 2007. The American Association of Petroleum Geologists. All rights reserved.

  2. 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.

  3. 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.

  4. 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

  5. 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...

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

    SciTech Connect

    E.W. Baxter

    2002-06-30

    The objective of this report period was to continue the development of the Gas Generator design, completion of the hardware and ancillary hardware fabrication and commence the Test Preparations for the testing of the non-polluting unique power turbine driven Gas Generator. Focus during this report period has been on completing the Gas Generator fabrication of hardware and ancillary hardware, and completion of unit closeout brazing and bonding. Because of unacceptable delays encountered in a previously competitively selected test site, CES initiated a re-competition of our testing program and selected an alternate test site. Following that selection, CES used all available resources to make preparations for testing the 10 Mw Gas Generator at the new testing site facilities of NTS at Saugus, CA.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 2002 Carolyn Sherif Award Address: Gender, Race, and Generation in a Midwest High School: Using Ethnographically Informed Methods in Psychology.

    ERIC Educational Resources Information Center

    Stewart, Abigail J.

    2003-01-01

    Suggests the value of ethnographically informed methods in the psychology of women, emphasizing the role of generation in psychology. Examines evidence from an ongoing, ethnographically informed study of high school graduates in the mid-1950s and late-1960s. The two generations of graduates have distinctive accounts of their experiences, with the…

  12. 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…

  13. 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

  14. 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.

  15. 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

  16. SULFUR REMOVAL FROM PIPE LINE NATURAL GAS FUEL: APPLICATION TO FUEL CELL POWER GENERATION SYSTEMS

    SciTech Connect

    King, David L.; Birnbaum, Jerome C.; Singh, Prabhakar

    2003-11-21

    Pipeline natural gas is being considered as the fuel of choice for utilization in fuel cell-based distributed generation systems because of its abundant supply and the existing supply infrastructure (1). For effective utilization in fuel cells, pipeline gas requires efficient removal of sulfur impurities (naturally occurring sulfur compounds or sulfur bearing odorants) to prevent the electrical performance degradation of the fuel cell system. Sulfur odorants such as thiols and sulfides are added to pipeline natural gas and to LPG to ensure safe handling during transportation and utilization. The odorants allow the detection of minute gas line leaks, thereby minimizing the potential for explosions or fires.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    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.

  3. Life Cycle Greenhouse Gas Emissions from Electricity Generation

    SciTech Connect

    None, None

    2013-01-01

    As clean energy increasingly becomes part of the national dialogue, lenders, utilities, and lawmakers need the most comprehensive and accurate information on GHG emissions from various sources of energy to inform policy, planning, and investment decisions. The National Renewable Energy Laboratory (NREL) recently led the Life Cycle Assessment (LCA) Harmonization Project, a study that gives decision makers and investors more precise estimates of life cycle GHG emissions for renewable and conventional generation, clarifying inconsistent and conflicting estimates in the published literature, and reducing uncertainty.

  4. 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

  5. Timing of oil and gas generation of petroleum systems in the Southwestern Wyoming Province

    USGS Publications Warehouse

    Roberts, L.N.R.; Lewan, M.D.; Finn, T.M.

    2004-01-01

    Burial history, thermal maturity, and timing of petroleum generation were modeled for eight key source-rock horizons at seven locations throughout the Southwestern Wyoming Province. The horizons are the bases of the Lower Permian Phosphoria Formation, the Upper Cretaceous Mowry Shale, Niobrara Formation, Baxter Shale (and equivalents), upper part of the Mesaverde Group, Lewis Shale, Lance Formation, and the Tertiary (Paleocene) Fort Union Formation. Burial history locations include three in the deepest parts of the province (Adobe Town in the Washakie Basin, Eagles Nest in the Great Divide Basin, and Wagon Wheel in the northern Green River Basin); two at intermediate basin depths (Federal 31-1 and Currant, Creek in the central and southern parts of the Green River Basin, respectively); and two relatively shallow locations (Bear 1 on the southeastern margin of the Sand Wash Basin and Bruff 2 on the Moxa arch). An overall ranking of the burial history locations in order of decreasing thermal maturity is Adobe Town > Eagles Nest > Wagon Wheel > Currant Creek > Federal 31-1 > Bear-1 > Bruff 2. The results of the models indicate that peak petroleum generation from Cretaceous oil- and gas-prone source rocks in the deepest parts of the province occurred from Late Cretaceous through middle Eocene. At the modeled locations, peak oil generation from source rocks of the Phosphoria Formation, which contain type-IIS kerogen, occurred in the Late Cretaceous (80 to 73 million years ago (Ma)). Gas generation from the cracking of Phosphoria oil reached a peak in the late Paleocene (57 Ma) only in the deepest parts of the province. The Mowry Shale, Niobrara Formation, and Baxter Shale (and equivalents) contain type-IIS or a mix of type-II and type-III kerogens. Oil generation from these units, in the deepest parts of the province, reached peak rates during the latest Cretaceous to early Paleocene (66 to 61 Ma). Only at these deepest locations did these units reach peak gas

  6. 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.

  7. Centrifugal spray singlet oxygen generator for a COIL with nitrogen as a buffer gas

    NASA Astrophysics Data System (ADS)

    Å palek, Otomar; Jirásek, Vít.; Čenský, Miroslav; Kodymová, Jarmila

    2012-01-01

    A scalable high pressure centrifugal spray generator of singlet oxygen for chemical oxygen-iodine laser (COIL) was developed. This generator uses nitrogen as chlorine diluting gas. Different spray nozzles were tested which could be assembled together and so enable a high chlorine flow rates for a high-power COIL. The designed generator can produce singlet oxygen, O2(1Δg), with reasonable chlorine utilization and O2(1Δg) yield even at very high generator pressures, which cannot be attained by other O2(1Δg) generators. This high-pressure operation is beneficial for a pressure recovery system of the laser. Another advantage of this generator is a very high BHP utilization. The problem of heating of exit gas was solved by introducing additional nitrogen between the separator rotor and stator.

  8. 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.

  9. 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.

  10. Next Generation Thermal Barrier Coatings for the Gas Turbine Industry

    NASA Astrophysics Data System (ADS)

    Curry, Nicholas; Markocsan, Nicolaie; Li, Xin-Hai; Tricoire, Aurélien; Dorfman, Mitch

    2011-01-01

    The aim of this study is to develop the next generation of production ready air plasma sprayed thermal barrier coating with a low conductivity and long lifetime. A number of coating architectures were produced using commercially available plasma spray guns. Modifications were made to powder chemistry, including high purity powders, dysprosia stabilized zirconia powders, and powders containing porosity formers. Agglomerated & sintered and homogenized oven spheroidized powder morphologies were used to attain beneficial microstructures. Dual layer coatings were produced using the two powders. Laser flash technique was used to evaluate the thermal conductivity of the coating systems from room temperature to 1200 °C. Tests were performed on as-sprayed samples and samples were heat treated for 100 h at 1150 °C. Thermal conductivity results were correlated to the coating microstructure using image analysis of porosity and cracks. The results show the influence of beneficial porosity on reducing the thermal conductivity of the produced coatings.

  11. Gas-phase generation of photoacoustic sound in an open environment.

    PubMed

    Yönak, Serdar H; Dowling, David R

    2003-12-01

    The photoacoustic effect is commonly exploited for molecular spectroscopy, nondestructive evaluation, and trace gas detection. Photoacoustic sound is produced when a photoactive material absorbs electromagnetic radiation and converts it to acoustic waves. This article focuses on the generation of photoacoustic sound from thermal expansion of photoactive gases due to unsteady heating from a laser light source, and extends the work of prior studies on photoacoustic sound generation in an open environment. Starting with the forced free-space wave equation, a simple model is constructed for photoacoustic sounds produced by both acoustically distributed and compact gas clouds. The model accounts for laser absorption through the Lambert-Beer law and includes the effects of photoactive gas cloud characteristics (shape, size, and concentration distribution), but does not include molecular diffusion, thermal conduction, convection, or the effects of acoustic propagation through sound-absorbing inhomogeneous media. This model is compared to experimentally measured photoacoustic sounds generated by scanning a 10.6-micron carbon dioxide (CO2) laser beam through small clouds of a photoactive gas, sulfur hexafluoride (SF6). For the current investigation, the photoactive gas clouds are formed either by low flow-rate calibrated leak sources or by a laminar jet emerging from a 1.6-mm-diam tube. Model-measurement comparisons are presented over a 3- to 160-kHz bandwidth. Signal pulse shapes from simple gas cloud geometries are found to match calculated results when unmeasured gas cloud characteristics within the model are adjusted.

  12. 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.

  13. Ultrafine particles and nitrogen oxides generated by gas and electric cooking

    PubMed Central

    Dennekamp, M; Howarth, S; Dick, C; Cherrie, J; Donaldson, K; Seaton, A

    2001-01-01

    OBJECTIVES—To measure the concentrations of particles less than 100 nm diameter and of oxides of nitrogen generated by cooking with gas and electricity, to comment on possible hazards to health in poorly ventilated kitchens.
METHODS—Experiments with gas and electric rings, grills, and ovens were used to compare different cooking procedures. Nitrogen oxides (NOx) were measured by a chemiluminescent ML9841A NOx analyser. A TSI 3934 scanning mobility particle sizer was used to measure average number concentration and size distribution of aerosols in the size range 10-500 nm.
RESULTS—High concentrations of particles are generated by gas combustion, by frying, and by cooking of fatty foods. Electric rings and grills may also generate particles from their surfaces. In experiments where gas burning was the most important source of particles, most particles were in the size range 15-40 nm. When bacon was fried on the gas or electric rings the particles were of larger diameter, in the size range 50-100 nm. The smaller particles generated during experiments grew in size with time because of coagulation. Substantial concentrations of NOX were generated during cooking on gas; four rings for 15 minutes produced 5 minute peaks of about 1000 ppb nitrogen dioxide and about 2000 ppb nitric oxide.
CONCLUSIONS—Cooking in a poorly ventilated kitchen may give rise to potentially toxic concentrations of numbers of particles. Very high concentrations of oxides of nitrogen may also be generated by gas cooking, and with no extraction and poor ventilation, may reach concentrations at which adverse health effects may be expected. Although respiratory effects of exposure to NOx might be anticipated, recent epidemiology suggests that cardiac effects cannot be excluded, and further investigation of this is desirable.


Keywords: cooking fuels; nitrogen oxides; ultrafine particles PMID:11452045

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. 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.

  1. A Simulator for a Hydrocarbon Ramrocket Fuel Gas Generator - First Phase Development

    DTIC Science & Technology

    1989-05-01

    deal of ramburner testing could also be accomplished to determine combustion efficiencies, pressure losses, high temperature materials performance , and...Sampling System 10 7.2.2 Gas Chromatography 11 8. OBSERVATIONS OF TEST HARDWARE PERFORMANCE 11 9. RESULTS AND DISCUSSION 13 9.1 Analysis of Zaccardi...as combuster flow fields would be much easier to perform without the added complication of firing a solid propellant gas generator nearby. A great

  2. 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.

  3. GETRAN: A generic, modularly structured computer code for simulation of dynamic behavior of aero- and power generation gas turbine engines

    NASA Astrophysics Data System (ADS)

    Schobeiri, M. T.; Attia, M.; Lippke, C.

    1994-07-01

    The design concept, the theoretical background essential for the development of the modularly structured simulation code GETRAN, and several critical simulation cases are presented in this paper. The code being developed under contract with NASA Lewis Research Center is capable of simulating the nonlinear dynamic behavior of single- and multispool core engines, turbofan engines, and power generation gas turbine engines under adverse dynamic operating conditions. The modules implemented into GETRAN correspond to components of existing and new-generation aero- and stationary gas turbine engines with arbitrary configuration and arrangement. For precise simulation of turbine and compressor components, row-by-row diabatic and adiabatic calculation procedures are implemented that account for the specific turbine and compressor cascade, blade geometry, and characteristics. The nonlinear, dynamic behavior of the subject engine is calculated solving a number of systems of partial differential equations, which describe the unsteady behavior of each component individually. To identify each differential equation system unambiguously, special attention is paid to the addressing of each component. The code is capable of executing the simulation procedure at four levels, which increase with the degree of complexity of the system and dynamic event. As representative simulations, four different transient cases with single- and multispool thrust and power generation engines were simulated. These transient cases vary from throttling the exit nozzle area, operation with fuel schedule, rotor speed control, to rotating stall and surge.

  4. 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.

  5. 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.

  6. 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.

  7. Gas flow and generation of x ray emission in WR+OB binaries

    NASA Technical Reports Server (NTRS)

    Usov, V. V.

    1991-01-01

    The supersonic flow of the ionized gas in WR+OB binaries and X-ray generation are considered. X-ray emission is caused by gas heating up to temperatures of 10(exp 7) to 10(exp 8) K behind the front of shock waves. These are found in the collision of gas flowing out from the WR star with either the OB star's surface or the gas of the OB star's wind. The distribution of temperature and concentration behind the shock front are obtained. Using these distributions, the spectral power of bremsstrahlung X-ray emission of hot gas is calculated. Possible reasons that lead to a considerable difference between the observed parameters of X-ray emission of the WR binary of V 444 Cygni and the theoretically expected are discussed.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Greenhouse gas emissions during plantation stage of palm oil-based biofuel production addressing different land conversion scenarios in Malaysia.

    PubMed

    Kusin, Faradiella Mohd; Akhir, Nurul Izzati Mat; Mohamat-Yusuff, Ferdaus; Awang, Muhamad

    2017-02-01

    The environmental impacts with regard to agro-based biofuel production have been associated with the impact of greenhouse gas (GHG) emissions. In this study, field GHG emissions during plantation stage of palm oil-based biofuel production associated with land use changes for oil palm plantation development have been evaluated. Three different sites of different land use changes prior to oil palm plantation were chosen; converted land-use (large and small-scales) and logged-over forest. Field sampling for determination of soil N-mineralisation and soil organic carbon (SOC) was undertaken at the sites according to the age of palm, i.e. <5 years (immature), 5-20 and >21 years (mature oil palms). The field data were incorporated into the estimation of nitrous oxide (N2O) and the resulting CO2-eq emissions as well as for estimation of carbon stock changes. Irrespective of the land conversion scenarios, the nitrous oxide emissions were found in the range of 6.47-7.78 kg N2O-N/ha resulting in 498-590 kg CO2-eq/ha. On the other hand, the conversion of tropical forest into oil palm plantation has resulted in relatively higher GHG emissions (i.e. four times higher and carbon stock reduction by >50%) compared to converted land use (converted rubber plantation) for oil palm development. The conversion from previously rubber plantation into oil palm plantation would increase the carbon savings (20% in increase) thus sustaining the environmental benefits from the palm oil-based biofuel production.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. Adaptive interpretation of gas well deliverability tests with generating data of the IPR curve

    NASA Astrophysics Data System (ADS)

    Sergeev, V. L.; Phuong, Nguyen T. H.; Krainov, A. I.

    2017-01-01

    The paper considers topical issues of improving accuracy of estimated parameters given by data obtained from gas well deliverability tests, decreasing test time, and reducing gas emissions into the atmosphere. The aim of the research is to develop the method of adaptive interpretation of gas well deliverability tests with a resulting IPR curve and using a technique of generating data, which allows taking into account additional a priori information, improving accuracy of determining formation pressure and flow coefficients, reducing test time. The present research is based on the previous theoretical and practical findings in the spheres of gas well deliverability tests, systems analysis, system identification, function optimization and linear algebra. To test the method, the authors used the field data of deliverability tests of two wells, run in the Urengoy gas and condensate field, Tyumen Oblast. The authors suggest the method of adaptive interpretation of gas well deliverability tests with the resulting IPR curve and the possibility of generating data of bottomhole pressure and a flow rate at different test stages. The suggested method allows defining the estimates of the formation pressure and flow coefficients, optimal in terms of preassigned measures of quality, and setting the adequate number of test stages in the course of well testing. The case study of IPR curve data processing has indicated that adaptive interpretation provides more accurate estimates on the formation pressure and flow coefficients, as well as reduces the number of test stages.

  9. 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

  10. Ultrasound imaging of oxidative stress in vivo with chemically-generated gas microbubbles.

    PubMed

    Perng, John Kangchun; Lee, Seungjun; Kundu, Kousik; Caskey, Charles F; Knight, Sarah F; Satir, Sarp; Ferrara, Katherine W; Taylor, W Robert; Degertekin, F Levent; Sorescu, Daniel; Murthy, Niren

    2012-09-01

    Ultrasound contrast agents (UCAs) have tremendous potential for in vivo molecular imaging because of their high sensitivity. However, the diagnostic potential of UCAs has been difficult to exploit because current UCAs are based on pre-formed microbubbles, which can only detect cell surface receptors. Here, we demonstrate that chemical reactions that generate gas forming molecules can be used to perform molecular imaging by ultrasound in vivo. This new approach was demonstrated by imaging reactive oxygen species in vivo with allylhydrazine, a liquid compound that is converted into nitrogen and propylene gas after reacting with radical oxidants. We demonstrate that allylhydrazine encapsulated within liposomes can detect a 10 micromolar concentration of radical oxidants by ultrasound, and can image oxidative stress in mice, induced by lipopolysaccharide, using a clinical ultrasound system. We anticipate numerous applications of chemically-generated microbubbles for molecular imaging by ultrasound, given ultrasound's ability to detect small increments above the gas saturation limit, its spatial resolution and widespread clinical use.

  11. [Measurement of regional blood flow using hydrogen gas generated by electrolysis (author's transl)].

    PubMed

    Koshu, K; Endo, S; Takaku, A; Saito, T

    1981-10-01

    Electrolytically generated hydrogen gas used to measure local blood flow by Stosseck et al. The data obtained by their method, however, did not correlated well with that obtained by original Aukland's method, hydrogen clearance method. We have tried to record the concentration of hydrogen gas after electrolytic generation of hydrogen gas at the white matter of the mongrel dogs. As a result, we found that its curves could be approximated to monoexponential curves during the first several minutes. This fact was also noticed in the experiment, in which circulation had been stopped due to cardiac arrest. A simple equation to calculate the regional blood flow was brought out through the approximation mentioned above. The values calculated by this new equation correlated well with that obtained by original hydrogen clearance method. This new method to detect the regional blood flow is simple and easy. Therefore it may contribute to some experiments, especially to the experiments with small animals.

  12. Microfluidic generation of uniform water droplets using gas as the continuous phase.

    PubMed

    Jiang, Kunqiang; Lu, Annie Xi; Dimitrakopoulos, Panagiotis; DeVoe, Don L; Raghavan, Srinivasa R

    2015-06-15

    Microfluidic schemes for forming uniform aqueous microdroplets usually rely on contacting the aqueous liquid (dispersed phase) with an immiscible oil (continuous phase). Here, we demonstrate that the oil can be substituted with gas (nitrogen or air) while still retaining the ability to generate discrete and uniform aqueous droplets. Our device is a capillary co-flow system, with the inner flow of water getting periodically dispersed into droplets by the external flow of gas. The droplet size and different formation modes can be tuned by varying the liquid and gas flow rates. Importantly, we identify the range of conditions that correspond to the "dripping mode", i.e., where discrete droplets are consistently generated with no satellites. We believe this is a significant development that will be beneficial for chemical and biological applications requiring clean and contaminant-free droplets, including DNA amplification, drug encapsulation, and microfluidic cell culture.

  13. Generation of terahertz radiation by focusing femtosecond bichromatic laser pulses in a gas or plasma

    SciTech Connect

    Chizhov, P A; Volkov, Roman V; Bukin, V V; Ushakov, A A; Garnov, Sergei V; Savel'ev-Trofimov, Andrei B

    2013-04-30

    The generation of terahertz radiation by focusing two-frequency femtosecond laser pulses is studied. Focusing is carried out both in an undisturbed gas and in a pre-formed plasma. The energy of the terahertz radiation pulses is shown to reduce significantly in the case of focusing in a plasma. (extreme light fields and their applications)

  14. 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...

  15. 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.

  16. Metathesis in the generation of low-temperature gas in marine shales

    PubMed Central

    2010-01-01

    The recent report of low-temperature catalytic gas from marine shales took on additional significance with the subsequent disclosure of natural gas and low-temperature gas at or near thermodynamic equilibrium in methane, ethane, and propane. It is important because thermal cracking, the presumed source of natural gas, cannot generate these hydrocarbons at equilibrium nor can it bring them to equilibrium over geologic time. The source of equilibrium and the source of natural gas are either the same (generation under equilibrium control) or closely associated. Here we report the catalytic interconversion of hydrocarbons (metathesis) as the source of equilibrium in experiments with Cretaceous Mowry shale at 100°C. Focus was on two metathetic equilibria: methane, ethane, and propane, reported earlier, Q (K = [(C1)*(C3)]/[(C2)2]), and between these hydrocarbons and n-butane, Q* (K = [(C1)*(n-C4)]/[(C2)*(C3)]), reported here for the first time. Two observations stand out. Initial hydrocarbon products are near equilibrium and have maximum average molecular weights (AMW). Over time, products fall from equilibrium and AMW in concert. It is consistent with metathesis splitting olefin intermediates [Cn] to smaller intermediates (fission) as gas generation creates open catalytic sites ([ ]): [Cn] + [ ] → [Cn-m] + [Cm]. Fission rates increasing exponentially with olefin molecular weight could contribute to these effects. AMW would fall over time, and selective fission of [C3] and [n-C4] would draw Q and Q* from equilibrium. The results support metathesis as the source of thermodynamic equilibrium in natural gas. PMID:20142998

  17. Metathesis in the generation of low-temperature gas in marine shales.

    PubMed

    Mango, Frank D; Jarvie, Daniel M

    2010-01-20

    The recent report of low-temperature catalytic gas from marine shales took on additional significance with the subsequent disclosure of natural gas and low-temperature gas at or near thermodynamic equilibrium in methane, ethane, and propane. It is important because thermal cracking, the presumed source of natural gas, cannot generate these hydrocarbons at equilibrium nor can it bring them to equilibrium over geologic time. The source of equilibrium and the source of natural gas are either the same (generation under equilibrium control) or closely associated. Here we report the catalytic interconversion of hydrocarbons (metathesis) as the source of equilibrium in experiments with Cretaceous Mowry shale at 100 degrees C. Focus was on two metathetic equilibria: methane, ethane, and propane, reported earlier, Q (K = [(C(1))*(C(3))]/[(C(2))(2)]), and between these hydrocarbons and n-butane, Q* (K = [(C(1))*(n-C(4))]/[(C(2))*(C(3))]), reported here for the first time. Two observations stand out. Initial hydrocarbon products are near equilibrium and have maximum average molecular weights (AMW). Over time, products fall from equilibrium and AMW in concert. It is consistent with metathesis splitting olefin intermediates [C(n)] to smaller intermediates (fission) as gas generation creates open catalytic sites ([ ]): [C(n)] + [ ] --> [C(n-m)] + [C(m)]. Fission rates increasing exponentially with olefin molecular weight could contribute to these effects. AMW would fall over time, and selective fission of [C(3)] and [n-C(4)] would draw Q and Q* from equilibrium. The results support metathesis as the source of thermodynamic equilibrium in natural gas.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Closed cycle MHD generator with nonuniform gas-plasma flow driving recombinated plasma clots

    SciTech Connect

    Slavin, V.S.; Danilov, V.V.; Sokolov, V.S.

    1996-12-31

    A new concept of a closed cycle MHD generator without alkali seed has been suggested. The essence of it is the phenomenon of frozen conductivity for recombined plasma which appears for noble gas at T{sub e} > 4,000 K. At the inlet of the MHD channel in supersonic flow of noble gas (He or Ar) the plasma clots with electron density about 10{sup 15} cm{sup {minus}3} are formed by pulsed intense electron beam with energy about 300 keV. Gas flow drives these clots in a cross magnetic field along the MHD channel which has electrodes connected with the load by Faraday scheme. The gas flow pushes plasma layers and produces electric power at the expense of enthalpy extraction. The numerical simulation has shown that a supersonic gas flow, containing about 4 plasma layers in the MHD channel simultaneously, is braked without shock waves creation. This type of the MHD generator can provide more than 30% enthalpy extraction ratio and about 80% isentropic efficiency. The advantages of the new concept are the following: (a) possibility of working at higher pressure and lower temperature, (b) operation with alkali seed.

  5. 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.

  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. 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

  8. 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.

  9. Electricity generation from synthesis gas by microbial processes: CO fermentation and microbial fuel cell technology.

    PubMed

    Kim, Daehee; Chang, In Seop

    2009-10-01

    A microbiological process was established to harvest electricity from the carbon monoxide (CO). A CO fermenter was enriched with CO as the sole carbon source. The DGGE/DNA sequencing results showed that Acetobacterium spp. were enriched from the anaerobic digester fluid. After the fermenter was operated under continuous mode, the products were then continuously fed to the microbial fuel cell (MFC) to generate electricity. Even though the conversion yield was quite low, this study proved that synthesis gas (syn-gas) can be converted to electricity with the aid of microbes that do not possess the drawbacks of metal catalysts of conventional methods.

  10. 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.

  11. 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

  12. 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.

  13. Thermal-maturity limit for primary thermogenic-gas generation from humic coals as determined by hydrous pyrolysis

    USGS Publications Warehouse

    Lewan, Michael; Kotarba, M.J.

    2014-01-01

    Hydrous-pyrolysis experiments at 360°C (680°F) for 72 h were conducted on 53 humic coals representing ranks from lignite through anthracite to determine the upper maturity limit for hydrocarbon-gas generation from their kerogen and associated bitumen (i.e., primary gas generation). These experimental conditions are below those needed for oil cracking to ensure that generated gas was not derived from the decomposition of expelled oil generated from some of the coals (i.e., secondary gas generation). Experimental results showed that generation of hydrocarbon gas ends before a vitrinite reflectance of 2.0%. This reflectance is equivalent to Rock-Eval maximum-yield temperature and hydrogen indices (HIs) of 555°C (1031°F) and 35 mg/g total organic carbon (TOC), respectively. At these maturity levels, essentially no soluble bitumen is present in the coals before or after hydrous pyrolysis. The equivalent kerogen atomic H/C ratio is 0.50 at the primary gas-generation limit and indicates that no alkyl moieties are remaining to source hydrocarbon gases. The convergence of atomic H/C ratios of type-II and -I kerogen to this same value at a reflectance of indicates that the primary gas-generation limits for humic coal and type-III kerogen also apply to oil-prone kerogen. Although gas generation from source rocks does not exceed vitrinite reflectance values greater than , trapped hydrocarbon gases can remain stable at higher reflectance values. Distinguishing trapped gas from generated gas in hydrous-pyrolysis experiments is readily determined by of the hydrocarbon gases when a -depleted water is used in the experiments. Water serves as a source of hydrogen in hydrous pyrolysis and, as a result, the use of -depleted water is reflected in the generated gases but not pre-existing trapped gases.

  14. 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.

  15. The DOE/NREL Next Generation Natural Gas Vehicle Program - An Overview

    SciTech Connect

    Kevin Walkowicz; Denny Stephens; Kevin Stork

    2001-05-14

    This paper summarizes the Next Generation Natural Gas Vehicle (NG-NGV) Program that is led by the U.S. Department Of Energy's (DOE's) Office of Heavy Vehicle Technologies (OHVT) through the National Renewable Energy Laboratory (NREL). The goal of this program is to develop and implement one Class 3-6 compressed natural gas (CNG) prototype vehicle and one Class 7-8 liquefied natural gas (LNG) prototype vehicle in the 2004 to 2007 timeframe. OHVT intends for these vehicles to have 0.5 g/bhp-hr or lower emissions of oxides of nitrogen (NOx) by 2004 and 0.2 g/bhp-hr or lower NOx by 2007. These vehicles will also have particulate matter (PM) emissions of 0.01 g/bhp-hr or lower by 2004. In addition to ambitious emissions goals, these vehicles will target life-cycle economics that are compatible with their conventionally fueled counterparts.

  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 Astrophysics Data System (ADS)

    Yesil, Oktay

    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. 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.

  19. 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.

  20. 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.

  1. The California Climate Action Registry: Development of methodologies for calculating greenhouse gas emissions from electricity generation

    SciTech Connect

    Price, Lynn; Marnay, Chris; Sathaye, Jayant; Muritshaw, Scott; Fisher, Diane; Phadke, Amol; Franco, Guido

    2002-08-01

    The California Climate Action Registry, which will begin operation in Fall 2002, is a voluntary registry for California businesses and organizations to record annual greenhouse gas emissions. Reporting of emissions in the Registry by a participant involves documentation of both ''direct'' emissions from sources that are under the entity's control and ''indirect'' emissions controlled by others. Electricity generated by an off-site power source is considered to be an indirect emission and must be included in the entity's report. Published electricity emissions factors for the State of California vary considerably due to differences in whether utility-owned out-of-state generation, non-utility generation, and electricity imports from other states are included. This paper describes the development of three methods for estimating electricity emissions factors for calculating the combined net carbon dioxide emissions from all generating facilities that provide electricity to Californians. We find that use of a statewide average electricity emissions factor could drastically under- or over-estimate an entity's emissions due to the differences in generating resources among the utility service areas and seasonal variations. In addition, differentiating between marginal and average emissions is essential to accurately estimate the carbon dioxide savings from reducing electricity use. Results of this work will be taken into consideration by the Registry when finalizing its guidance for use of electricity emissions factors in calculating an entity's greenhouse gas emissions.

  2. 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.

  3. 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.

  4. 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.

  5. Instantaneous insulation in a micro-slab: A mechanism for flow generation in a rarefied gas

    NASA Astrophysics Data System (ADS)

    Manela, A.; Pogorelyuk, L.

    2016-12-01

    We analyze the response of a gas in a micro-slab, set at an initial pure-conduction state, to instantaneous thermal insulation of its boundaries. In line with ongoing efforts in generating gas flows at the microscale, thermal insulation is suggested as a means for flow excitation with no moving parts. The problem is analyzed in the entire range of gas rarefaction rates and for arbitrary initial temperature differences between the walls. Analytical solutions are obtained in the linearized limit of small temperature differences for large (collisionless) and small (continuum) Knudsen numbers. These solutions are supported by direct simulation Monte Carlo calculations, which are then used to investigate the nonlinear problem with large initial temperature differences. Followed by the system's initial state, boundary insulation results in a series of time-decaying waves, propagating across the slab, and transferring the system between its conductive and adiabatic equilibrium states. While larger initial temperature differences result in higher flow rates, it is found that nonlinear effects reduce the efficiency of flow excitation through boundaries insulation. At high Knudsen numbers, this is rationalized through the system's initial state, in which the gas uniform temperature is lower than the arithmetic mean of walls temperatures. At low Knudsen numbers, the dominant effect of molecular collisions causes thermal dissipation, which in turn results in kinetic energy losses. The analysis may be readily applied to calculate the gas response to arbitrary time variations of the boundary-imposed heat flux.

  6. 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.

  7. 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

  8. 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.

  9. Spatial characterization of extreme ultraviolet plasmas generated by laser excitation of xenon gas targets

    NASA Astrophysics Data System (ADS)

    Kranzusch, Sebastian; Peth, Christian; Mann, Klaus

    2003-02-01

    At Laser-Laboratorium Göttingen laser-plasma sources were tested, which are going to be used for characterization of optical components and sensoric devices in the wavelength region from 11 to 13 nm. In all cases extreme ultraviolet (EUV) radiation is generated by focusing a Q-switched Nd:YAG laser into a pulsed gas puff target. By the use of xenon or oxygen as target gas, broadband as well as narrowband EUV radiation is obtained, respectively. Different types of valves and nozzles were tested in order to optimize the emitted radiation with respect to maximum EUV intensities, small source diameters, and positional stability. The investigation of these crucial source parameters was performed with specially designed EUV pinhole cameras, utilizing evaluation algorithms developed for standardized laser beam characterization. In addition, a rotatable pinhole camera was developed which allows both spatially and angular resolved monitoring of the soft x-ray emission characteristics. With the help of this camera a strong angular dependence of the EUV intensity was found. The data were compared with fluorescence measurements for visualization of the target gas jet. The experimental observations can be explained by reabsorption of the generated EUV radiation in the surrounding target gas, as supported by semiempirical model calculations based on the attenuation in the three-dimensional gas density according to Lambert-Beer's law. As a consequence of the presented investigations, an optimization of the EUV source with respect to intensity, plasma shape, and angular dependence is achieved, resulting in a spherical plasma of 200 μm diameter and a 50% increase of the EUV pulse energy.

  10. 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,…

  11. 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

  12. Hydrogen generation in a microhollow cathode discharge in high-pressure ammonia-argon gas mixtures

    NASA Astrophysics Data System (ADS)

    Qiu, H.; Martus, K.; Lee, W. Y.; Becker, K.

    2004-04-01

    We explored the feasibility of using a single flow-through microhollow cathode discharge (MHCD) as a non-thermal plasma source for hydrogen (H2) production for portable fuel cell applications. The MHCD device consisted of two thin metal electrodes separated by a mica spacer with a single-hole, roughly 100 [mu]m in diameter, through all three layers. The efficiency of the MHCD reactor for H2 generation from NH3 was analyzed by monitoring the products formed in the discharge in a mass spectrometer. Using a gas mixture of up to 10% NH3 in Ar at pressures up to one atmosphere, the MHCD reactor achieved a maximum ammonia conversion of slightly more than 20%. The overall power efficiency of the MHCD reactor reached a peak value of about 11%. The dependence of NH3 conversion and power efficiency on the residence time of the gas in the MHCD plasma was studied. Experiments using pulsed excitation of the MHCD plasma indicated that pulsing can increase the power efficiency. Design and operating criteria are proposed for a microplasma-based H2 generator that can achieve a power efficiency above the break-even point, i.e., a microplasma reactor that requires less electrical power to generate and maintain the plasma than the power that can be obtained from the conversion of the H2 generated in the microplasma reactor.

  13. 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.

  14. 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

  15. 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

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

    2014-12-01

    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.

  16. Ultrasound Imaging of Oxidative Stress In Vivo with Chemically-Generated Gas Microbubbles

    PubMed Central

    Perng, John Kangchun; Lee, Seungjun; Kundu, Kousik; Caskey, Charles F.; Knight, Sarah F.; Satir, Sarp; Ferrara, Katherine W.; Taylor, W. Robert; Degertekin, F. Levent; Sorescu, Daniel; Murthy, Niren

    2014-01-01

    Ultrasound contrast agents (UCAs) have tremendous potential for in vivo molecular imaging because of their high sensitivity. However, the diagnostic potential of UCAs has been difficult to exploit because current UCAs are based on pre-formed microbubbles, which can only detect cell surface receptors. Here, we demonstrate that chemical reactions that generate gas forming molecules can be used to perform molecular imaging by ultrasound in vivo. This new approach was demonstrated by imaging reactive oxygen species in vivo with allylhydrazine, a liquid compound that is converted into nitrogen and propylene gas after reacting with radical oxidants. We demonstrate that allylhydrazine encapsulated within liposomes can detect a 10 micromolar concentration of radical oxidants by ultrasound, and can image oxidative stress in mice, induced by lipopolysaccharide, using a clinical ultrasound system. We anticipate numerous applications of chemically-generated microbubbles for molecular imaging by ultrasound, given ultrasound’s ability to detect small increments above the gas saturation limit, its spatial resolution and widespread clinical use. PMID:22562306

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. The application of a new second-generation highstrength proppant in tight gas reservoirs

    SciTech Connect

    Callanan, M.J.; Cipolla, C.L.; Lewis, P.E.

    1983-03-01

    An analysis is made to illustrate the effectiveness of a new second generation high strength low density proppant as compared to that of sintered bauxite and Ottawa sand in a variety of applications. This is accomplished through the use of a reservoir simulator and a fracture design program. Gas producing formations are simulated which exhibit permeabilities between 0.001 md and 0.1 md and closure stresses up to 9500 psi. In these simulations the second generation proppant and sintered bauxite yield essentially identical production histories. However, the second generation proppant shows far superior performance to Ottawa sand in all applications. Also shown are cases revealing that tail-ins with the second generation proppant can yield a higher return on investment than pumping all high strength proppant. The simulations reveal the importance of non-Darcy flow and conductivity damage considerations in proppant selection. It is shown that these two factors have much less of an effect on the performance of the second generation proppant than on that of sand. With all of this considered the second generation proppant should prove to have a substantial economic advantage over both sintered bauxite and sand in a variety of applications.

  2. 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.

  3. Generation of naphthoquinone radical anions by electrospray ionization: solution, gas-phase, and computational chemistry studies.

    PubMed

    Vessecchi, Ricardo; Naal, Zeki; Lopes, José N C; Galembeck, Sérgio E; Lopes, Norberto P

    2011-06-02

    Radical anions are present in several chemical processes, and understanding the reactivity of these species may be described by their thermodynamic properties. Over the last years, the formation of radical ions in the gas phase has been an important issue concerning electrospray ionization mass spectrometry studies. In this work, we report on the generation of radical anions of quinonoid compounds (Q) by electrospray ionization mass spectrometry. The balance between radical anion formation and the deprotonated molecule is also analyzed by influence of the experimental parameters (gas-phase acidity, electron affinity, and reduction potential) and solvent system employed. The gas-phase parameters for formation of radical species and deprotonated species were achieved on the basis of computational thermochemistry. The solution effects on the formation of radical anion (Q(•-)) and dianion (Q(2-)) were evaluated on the basis of cyclic voltammetry analysis and the reduction potentials compared with calculated electron affinities. The occurrence of unexpected ions [Q+15](-) was described as being a reaction between the solvent system and the radical anion, Q(•-). The gas-phase chemistry of the electrosprayed radical anions was obtained by collisional-induced dissociation and compared to the relative energy calculations. These results are important for understanding the formation and reactivity of radical anions and to establish their correlation with the reducing properties by electrospray ionization analyses.

  4. Hydrogen sulfide generation by reaction of natural gas, sulfur, and steam. Report of investigations/1981

    SciTech Connect

    Crane, S.R.; Crocker, L.; Nissen, W.I.

    1981-07-01

    One Bureau of Mines goal is to minimize the undesirable environmental impacts associated with industrial plants emitting waste gases containing SO/sub 2/. To help meet this goal, a regenerable flue gas desulfurization process was developed. This process, known as the citrate process, uses a buffered weak acid solution to absorb SO/sub 2/ from the waste gas. The absorbed SO/sub 2/ is reacted with H/sub 2/S to precipitate elemental sulfur and regenerate the solution for recycle. The H/sub 2/S feedstock for the process, if not otherwise available, may be produced by reacting two-thirds of the recovered elemental sulfur with natural gas and steam. Laboratory investigations and pilot plant operations were conducted by the Bureau to determine if H2S from the natural gas, sulfur, and steam reaction was suitable for the citrate process. The laboratory investigations, in which an H2S generator was integrated with other citrate process operations, provided a basis for design and operation of the pilot plant. The objective of the pilot plant was primarily to provide H2S for the citrate process pilot plant at the Bunker Hill Co. lead smelter in Kellogg, Idaho.

  5. 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.

  6. Singlet oxygen generation on porous superhydrophobic surfaces: effect of gas flow and sensitizer wetting on trapping efficiency.

    PubMed

    Zhao, Yuanyuan; Liu, Yang; Xu, Qianfeng; Barahman, Mark; Bartusik, Dorota; Greer, Alexander; Lyons, Alan M

    2014-11-13

    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 ((1)O2) 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.

  7. 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

  8. 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.

  9. Gas spark switches with increased operating life for Marx generator of lightning test complex

    NASA Astrophysics Data System (ADS)

    Bykov, Yu. A.; Krastelev, E. G.

    2016-12-01

    A new design of gas spark switches with an increased operating life and stable dynamic characteristics for the Marx generator of the lightning test complex has been developed. The switches are characterized by the following parameters in the mode of operation: voltage up to 80 kV, discharge current up to 50 kA, flowing charge up to 3.5 C/pulse. An increased operating life is achieved by using torus-shaped electrodes with increased working surface area and a trigger electrode in the form of a thick disk with a hole located between them. Low breakdown delay time and high stability of breakdown voltage under dynamic conditions are provided by gas preionization in the spark gap using UV radiation of an additional corona discharge in the axial region.

  10. Generation of tunable octave-spanning mid-infrared pulses by filamentation in gas media.

    PubMed

    Cheng, Mark; Reynolds, Anthony; Widgren, Heather; Khalil, Munira

    2012-06-01

    The continued development of femtosecond mid-infrared (IR) sources with ultrabroad spectral width is critical for probing and controlling complex molecular structural dynamics on an ultrafast timescale. We report on a sub-20 fs, coherent mid-IR source with an octave-spanning spectral bandwidth (>2000 cm(-1)) tunable from 2-8 micrometers (37.5-150 THz), with energy >0.4 μJ/pulse at 1 kHz. The mid-IR pulses are generated by four-wave mixing during the filamentation of intense 800 nm and 400 nm pulses in various gas media. Spectral tunability is achieved by the choice of gas, pressure and input 800 nm pulse energy.

  11. 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

  12. NH4HCO3 gas-generating liposomal nanoparticle for photoacoustic imaging in breast cancer.

    PubMed

    Xia, Jizhu; Feng, Gang; Xia, Xiaorong; Hao, Lan; Wang, Zhigang

    2017-01-01

    In this study, we have developed a biodegradable nanomaterial for photoacoustic imaging (PAI). Its biodegradation products can be fully eliminated from a living organism. It is a gas-generating nanoparticle of liposome-encapsulating ammonium bicarbonate (NH4HCO3) solution, which is safe, effective, inexpensive, and free of side effects. When lasers irradiate these nanoparticles, NH4HCO3 decomposes to produce CO2, which can absorb much of the light energy under laser irradiation with a specific wavelength, and then expand under heat to generate a thermal acoustic wave. An acoustic detector can detect this wave and show it as a photoacoustic signal on a display screen. The intensity of the photoacoustic signal is enhanced corresponding to an increase in time, concentration, and temperature. During in vivo testing, nanoparticles were injected into tumor-bearing nude mice through the caudal vein, and photoacoustic signals were detected from the tumor, reaching a peak in 4 h, and then gradually disappearing. There was no damage to the skin or subcutaneous tissue from laser radiation. Our developed gas-generating nanomaterial, NH4HCO3 nanomaterial, is feasible, effective, safe, and inexpensive. Therefore, it is a promising material to be used in clinical PAI.

  13. 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.

  14. 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.

  15. NH4HCO3 gas-generating liposomal nanoparticle for photoacoustic imaging in breast cancer

    PubMed Central

    Xia, Jizhu; Feng, Gang; Xia, Xiaorong; Hao, Lan; Wang, Zhigang

    2017-01-01

    In this study, we have developed a biodegradable nanomaterial for photoacoustic imaging (PAI). Its biodegradation products can be fully eliminated from a living organism. It is a gas-generating nanoparticle of liposome-encapsulating ammonium bicarbonate (NH4HCO3) solution, which is safe, effective, inexpensive, and free of side effects. When lasers irradiate these nanoparticles, NH4HCO3 decomposes to produce CO2, which can absorb much of the light energy under laser irradiation with a specific wavelength, and then expand under heat to generate a thermal acoustic wave. An acoustic detector can detect this wave and show it as a photoacoustic signal on a display screen. The intensity of the photoacoustic signal is enhanced corresponding to an increase in time, concentration, and temperature. During in vivo testing, nanoparticles were injected into tumor-bearing nude mice through the caudal vein, and photoacoustic signals were detected from the tumor, reaching a peak in 4 h, and then gradually disappearing. There was no damage to the skin or subcutaneous tissue from laser radiation. Our developed gas-generating nanomaterial, NH4HCO3 nanomaterial, is feasible, effective, safe, and inexpensive. Therefore, it is a promising material to be used in clinical PAI. PMID:28293107

  16. 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.

  17. Gas Generation Rates as an Indicator for the Long Term Stability of Radioactive Waste Products

    SciTech Connect

    Steyer, S.; Brennecke, P.; Bandt, G.; Kroger, H.

    2007-07-01

    Pursuant to the 'Act on the Peaceful Utilization of Atomic Energy and the Protection against its Hazards' (Atomic Energy Act) the Federal Office for Radiation Protection (Bundesamt fuer Strahlenschutz, BfS) is legally responsible for the construction and operation of federal facilities for the disposal of radioactive waste. Within the scope of this responsibility, particular due to par. 74(1) Ordinance on Radiation Protection, BfS defines all safety-related requirements on waste packages envisaged for disposal, establishes guidelines for the conditioning of radioactive waste and approves the fulfillment of the waste acceptance requirements within the radioactive waste quality control system. BfS also provides criteria to enable the assessment of methods for the treatment and packaging of radioactive waste to produce waste packages suitable for disposal according to par. 74(2) Ordinance on Radiation Protection. Due to the present non-availability of a repository in Germany, quality control measures for all types of radioactive waste products are carried out prior to interim storage with respect to the future disposal. As a result BfS approves the demonstrated properties of the radioactive waste packages and confirms the fulfillment of the respective requirements. After several years of storage the properties of waste packages might have changed. By proving, that such changes have no significant impact on the quality of the waste product, the effort of requalification could be minimized. Therefore, data on the long-term behavior of radioactive waste products need to be acquired and indicators to prove the long-term stability have to be quantified. Preferably, such indicators can be determined easily with non-destructive methods, even for legacy waste packages. A promising parameter is the gas generation rate. The relationship between gas generation rate and long term stability is presented as first result of an ongoing study on behalf of BfS. Permissible gas

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. A study of the feasibility of directly applying gas generator systems to space shuttle mechanical functions

    NASA Technical Reports Server (NTRS)

    Lake, E. R.

    1974-01-01

    This study examined the current status and potential application of pyrotechnic gas generators and energy convertors for the space shuttle program. While most pyrotechnic devices utilize some form of linear actuation, only limited use of rotary actuators has been observed. This latter form of energy conversion, using a vane-type actuator as optimum, offers considerable potential in the area of servo, as well as non-servo systems, and capitalizes on a means of providing prolonged operating times. Pyrotechnic devices can often be shown to provide the optimum means of attaining a truly redundant back-up to a primary, non-pyrotechnic system.

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. High-order-harmonic generation using gas-phase H{sub 2}O molecules

    SciTech Connect

    Zhao Songfeng; Jin, Cheng; Le, Anh-Thu; Lin, C. D.; Lucchese, R. R.

    2011-03-15

    We investigate high-order-harmonic generation of isotropically distributed gas-phase H{sub 2}O molecules exposed to an intense laser field. The induced dipole of each individual molecule by the laser field is first calculated using the recently developed quantitative rescattering theory. In a thin medium, harmonic spectra generated coherently from all the molecules are then calculated by solving Maxwell's equation of propagation. By using accurate transition dipoles of H{sub 2}O, we show that the harmonics in the lower plateau region are quite different from models that employ the simpler strong-field approximation. We also examine the magnitude and phase of the harmonics and their dependence on laser focusing conditions.

  8. Nonlinear absorption and harmonic generation of laser in a gas with anharmonic clusters

    SciTech Connect

    Kumar, Manoj; Tripathi, V. K.

    2013-02-15

    The nonlinear absorption and harmonic generation of intense short pulse laser in a gas embedded with anharmonic clusters are investigated theoretically. When the laser induced excursion of cluster electrons becomes comparable to cluster radius, the restoration force on electrons no longer remains linearly proportional to the excursion. As a consequence, the plasmon resonance is broadened, leading to broadband laser absorption. It also leads to second and third harmonic generations, at much higher level than the one due to ponderomotive nonlinearity. The harmonic yield is resonantly enhanced at the plasmon resonance {omega}={omega}{sub pe}/{radical}(3), where {omega} is the frequency of the laser and {omega}{sub pe} is the plasma frequency of cluster electrons.

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

    SciTech Connect

    Johnson, Jay Dean; 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.

  10. 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...

  11. Keynote address

    SciTech Connect

    Cheney, D.

    1997-12-31

    March 10th is an anniversary date for Dick Cheney. Eight years ago today President Bush asked him to be his Secretary of Defense. He was his second choice. John Tower was his first. On March 17, 1989, Cheney was confirmed and sworn into the office of Secretary of Defense. He quickly began closing down his office on Capital Hill and he reported to work on March 18. Much changed for him that day, but not everything. He still had constituents. But instead of the residents of Wyoming, he represented the entire Armed forces of the United States of America. For this convention, he was asked to discuss the worldwide reserves and associated development risks, the risks and rewards in the US industry and 21st Century vision for energy within the US. He discusses the Halliburton view on the natural gas energy future, the US role, implications for a new business model, and political risk.

  12. 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.

  13. 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

    2015-10-06

    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.

  14. 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.

  15. [Efficiency of oxidant gas generator cells powered by electric or solar energy].

    PubMed

    Brust Carmona, H; Benitez, A; Zarco, J; Sánchez, E; Mascher, I

    1998-02-01

    Diseases caused by microbial contaminants in drinking water continue to be a serious problem in countries like Mexico. Chlorination, using chlorine gas or chlorine compounds, is one of the best ways to treat drinking water. However, difficulties in handling chlorine gas and the inefficiency of hypochlorite solution dosing systems--due to sociopolitical, economic, and cultural factors--have reduced the utility of these chlorination procedures, especially in far-flung and inaccessible rural communities. These problems led to the development of appropriate technologies for the disinfection of water by means of the on-site generation of mixed oxidant gases (chlorine and ozone). This system, called MOGGOD, operates through the electrolysis of a common salt solution. Simulated system evaluation using a hydraulic model allowed partial and total costs to be calculated. When powered by electrical energy from the community power grid, the system had an efficiency of 90%, and in 10 hours it was able to generate enough gases to disinfect about 200 m3 of water at a cost of approximately N$8 (US $1.30). When the electrolytic cell was run on energy supplied through a photoelectric cell, the investment costs were higher. A system fed by photovoltaic cells could be justified in isolated communities that lack electricity but have a gravity-fed water distribution system.

  16. 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.

  17. 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.

  18. Design/build/mockup of the Waste Isolation Pilot Plant gas generation experiment glovebox

    SciTech Connect

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

    1996-10-01

    A glovebox was designed, fabricated, and mocked-up for the WIPP Gas Generation Experiments (GGE) being conducted at ANL-W. GGE will determine the gas generation rates from materials in contact handled transuranic waste at likely long term repository temperature and pressure conditions. Since the customer`s schedule did not permit time for performing R&D of the support systems, designing the glovebox, and fabricating the glovebox in a serial fashion, a parallel approach was undertaken. As R&D of the sampling system and other support systems was initiated, a specification was written concurrently for contracting a manufacturer to design and build the glovebox and support equipment. The contractor understood that the R&D being performed at ANL-W would add additional functional requirements to the glovebox design. Initially, the contractor had sufficient information to design the glovebox shell. Once the shell design was approved, ANL-W built a full scale mockup of the shell out of plywood and metal framing; support systems were mocked up and resultant information was forwarded to the glovebox contractor to incorporate into the design. This approach resulted in a glovebox being delivered to ANL-W on schedule and within budget.

  19. 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.

  20. 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.

  1. Electric Power Generation Using Low Bandgap TPV Cells in a Gas-fired Heating Furnace

    NASA Astrophysics Data System (ADS)

    Qiu, K.; Hayden, A. C. S.

    2003-01-01

    Low bandgap TPV cells are preferred for electric power generation in TPV cogeneration systems. Recently, significant progress has been made in fabrication of low bandgap semiconductor TPV devices, such as InGaAsSb and InGaAs cells. However, it appears that only limited data are available in the literature with respect to the performance of these TPV cells in combustion-driven TPV systems. In the research presented in this paper, power generation using recently-developed InGaAsSb TPV cells has been investigated in a gas-fired space heating appliance. The combustion performance of the gas burner associated with a broadband radiator was evaluated experimentally. The radiant power density and radiant efficiency of the gas-heated radiator were determined at different degrees of exhaust heat recuperation. Heat recuperation is shown to have a certain effect on the combustion operation and radiant power output. The electric output characteristics of the InGaAsSb TPV devices were investigated under various combustion conditions. It was found that the cell short circuit density was greater than 1 A/cm2 at a radiator temperature of 930°C when an optical filter was used. An electric power density of 0.54 W/cm2 was produced at a radiator temperature of 1190°C. Furthermore, modeling calculations were carried out to reveal the influence of TPV cell bandgap and radiator temperature on power output and conversion efficiency. Finally, the design aspects of combustion-driven TPV systems were analyzed, showing that development of a special combustion device with high conversion level of fuel chemical energy to useful radiant energy is required, to improve further the system efficiency.

  2. 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.

  3. 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

  4. Electron-beam generation in a wide-aperture open gas discharge: A comparative study for different inert gases

    SciTech Connect

    Bokhan, P. A.; Zakrevsky, Dm. E.

    2010-08-30

    In the present study, electron-beam generation by open discharges was examined. The study was performed at gas pressures up to 20 Torr, and covered all inert gases. At voltages up to 8 kV, electron-beam currents up to 1600 A with current density {approx}130 A/cm{sup 2} and a beam generation efficiency in excess of 93% were obtained. The production of electrons from cold cathode was concluded to be of photoemissive nature, enabling the production of high-intensity electron beams in any noble gas or in a mixture of a noble gas with molecular gases irrespective of cathode material.

  5. 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

  6. 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.

  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. Convocation address.

    PubMed

    Kakodkar, A

    1999-07-01

    This convocation addressed by Dr. Anil Kakodkar focuses on the challenges faced by graduating students. In his speech, he emphasized the high level of excellence achieved by the industrial sector; however, he noted that there has been a loss of initiative in maximizing value addition, which was worsened by an increasing population pressure. In facing a stiff competition in the external and domestic markets, it is imperative to maximize value addition within the country in a competitive manner and capture the highest possible market share. To achieve this, high-quality human resources are central. Likewise, family planning programs should become more effective and direct available resources toward national advantage. To boost the domestic market, he suggests the need to search for strengths to achieve leadership position in those areas. First, an insight into the relationship between the lifestyles and the needs of our people and the natural resource endowment must be gained. Second, remodeling of the education system must be undertaken to prepare the people for adding the necessary innovative content in our value addition activities. Lastly, Dr. Kakodkar emphasizes the significance of developing a strong bond between parents and children to provide a sound foundation and allow the education system to grow upon it.

  9. Design and Operation of the Synthesis Gas Generator System for Reformed Propane and Glycerin Combustion

    NASA Astrophysics Data System (ADS)

    Pickett, Derek Kyle

    Due to an increased interest in sustainable energy, biodiesel has become much more widely used in the last several years. Glycerin, one major waste component in biodiesel production, can be converted into a hydrogen rich synthesis gas to be used in an engine generator to recover energy from the biodiesel production process. This thesis contains information detailing the production, testing, and analysis of a unique synthesis generator rig at the University of Kansas. Chapter 2 gives a complete background of all major components, as well as how they are operated. In addition to component descriptions, methods for operating the system on pure propane, reformed propane, reformed glycerin along with the methodology of data acquisition is described. This chapter will serve as a complete operating manual for future students to continue research on the project. Chapter 3 details the literature review that was completed to better understand fuel reforming of propane and glycerin. This chapter also describes the numerical model produced to estimate the species produced during reformation activities. The model was applied to propane reformation in a proof of concept and calibration test before moving to glycerin reformation and its subsequent combustion. Chapter 4 first describes the efforts to apply the numerical model to glycerin using the calibration tools from propane reformation. It then discusses catalytic material preparation and glycerin reformation tests. Gas chromatography analysis of the reformer effluent was completed to compare to theoretical values from the numerical model. Finally, combustion of reformed glycerin was completed for power generation. Tests were completed to compare emissions from syngas combustion and propane combustion.

  10. Monodisperse, submicrometer droplets via condensation of microfluidic-generated gas bubbles.

    PubMed

    Seo, Minseok; Matsuura, Naomi

    2012-09-10

    Microfluidics (MFs) can produce monodisperse droplets with precise size control. However, the synthesis of monodisperse droplets much smaller than the minimum feature size of the microfluidic device (MFD) remains challenging, thus limiting the production of submicrometer droplets. To overcome the minimum micrometer-scale droplet sizes that can be generated using typical MFDs, the droplet material is heated above its boiling point (bp), and then MFs is used to produce monodisperse micrometer-scale bubbles (MBs) that are easily formed in the size regime where standard MFDs have excellent size control. After MBs are formed, they are cooled, condensing into dramatically smaller droplets that are beyond the size limit achievable using the original MFD, with a size decrease corresponding to the density difference between the gas and liquid phases of the droplet material. Herein, it is shown experimentally that monodisperse, submicrometer droplets of predictable sizes can be condensed from a monodisperse population of MBs as generated by MFs. Using perfluoropentane (PFP) as a representative solvent due to its low bp (29.2 °C), it is demonstrated that monodisperse PFP MBs can be produced at MFD temperatures >3.6 °C above the bp of PFP over a wide range of sizes (i.e., diameters from 2 to 200 μm). Independent of initial size, the generated MBs shrink rapidly in size from about 3 to 0 °C above the bp of PFP, corresponding to a phase change from gas to liquid, after which they shrink more slowly to form fully condensed droplets with diameters 5.0 ± 0.1 times smaller than the initial size of the MBs, even in the submicrometer size regime. This new method is versatile and flexible, and may be applied to any type of low-bp solvent for the manufacture of different submicrometer droplets for which precisely controlled dimensions are required.

  11. 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.

  12. 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

  13. 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

  14. Radiological impact of NORM generated by oil and gas industries in the kingdom of Bahrain.

    PubMed

    Husain, Husain; Sakhnini, Lama

    2017-02-01

    A study of the external background radiation in areas affected by NORM generated by oil and gas industrial activities has been performed in the Kingdom of Bahrain. In this framework, two experimental residential areas, Awali and Riffa Views, were selected due to the presence of extensive oil and gas exploration and transportation. Additionally, two control residential areas, Isa Town and Al-Budaiya Village, were selected as they lack any industrial activities that would disrupt the radiation profile. The radiation dose rates were measured using Colibri Very Low Dose radiation survey meter with a built-in GPS. A total of 317 dose rates with their GPS coordinates were acquired. The lowest dose rate was 0.02 μSv/h acquired in Isa Town while the highest dose rate was 0.37 μSv/h acquired in Awali. Since there were no studies performed in the Kingdom to measure the average background radiation, the average external background radiation calculated from the control areas was used in this study which is 0.75 ± 0.31 mSv/y. The measured mean annual equivalent doses above the background radiation levels in Isa Town, Al-Budaiya, Riffa Views and Awali were -0.05 ± 0.05 mSv/y, 0.04 ± 0.04 mSv/y, 0.62 ± 0.13 mSv/y and 1.32 ± 0.35 mSv/y respectively. In other words, the radiation measurements were notably higher in the experimental areas. This was particularly true in south and southwestern Awali where the annual equivalent dose in some areas reached 2.49 mSv/y above average background levels. The geological constituent of the earth crust could be one source that contribute to overall background radiation. However, presence of NORM generated by extensive oil and gas operations and transportation is stronger justification for the higher radiation readings in the experimental areas than geological characteristic factor. Such high radiation values were found only near oil and gas installations and not in other locations of the same areas.

  15. 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.

  16. Estimation of greenhouse gas generation in wastewater treatment plants--model development and application.

    PubMed

    Bani Shahabadi, M; Yerushalmi, L; Haghighat, F

    2010-02-01

    A comprehensive mathematical model has been developed to estimate greenhouse gas (GHG) emissions by wastewater treatment plants (WWTP) resulting from on-site and off-site activities. The contribution of individual processes to the production of GHGs in a typical hybrid treatment system for food processing wastewaters has been determined. The results show that the recovery of biogas and its reuse as fuel have a remarkable impact on GHG emissions and reduce the overall emissions by 1023 kg CO(2)e d(-1) from a total of 7640 kg CO(2)e d(-1) when treating a wastewater at 2000 kg BOD d(-1). Furthermore, the recovery of biogas and its combustion may be used to cover the entire energy needs of the treatment plant for aeration, heating and electricity generation while creating emissions credit equal to 34 kg CO(2)e d(-1). The off-site GHG emissions resulting from the manufacturing of material for on-site usage were identified as the major source of GHG generation in hybrid treatment systems. These emissions account for the generation of 4138 kg CO(2)e d(-1), or 62% of the overall GHG emissions when biogas recovery is carried out. The inclusion of GHG emissions from nutrient removal as well as off-site processes in the overall GHG emissions of WWTPs increased the accuracy and completeness of this estimation, lending support to the novelty of the present study.

  17. 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

  18. 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.

  19. Opening Address

    NASA Astrophysics Data System (ADS)

    Crovini, L.

    1994-01-01

    IMGC this is an extremely valuable opportunity to compare our results with others using combined x-ray and optical interferometry to measure Si lattice spacing and dimensional and mass metrology to determine Si density. The initial impetus for the organization of this workshop was given by several colleagues, and with special emphasis and competence by the late Prof. Peter Seyfried of the PTB. We all mourn the loss of such a distinguished scientist to whom very important achievements in NA determination have to be credited. Prof. Seyfried was well known at the IMGC, some of our scientists having very profitably cooperated with him and his co-workers—a cooperation that is being steadily carried on. I wish to acknowledge the endorsements of the Regione Piemonte, of the CNR, of Turin University, and of the Commission of the European Communities, in terms of grants and other resources without which the workshop could not have been realized. I also wish to very warmly thank my colleagues on the Organizing Committee who have worked so well for this event. Lastly, I am pleased to acknowledge the fruitful cooperation between the IMGC and the Istituto di Fisica Generale "A Avogadro"—not the first case of its kind and, I am convinced, not the last. To conclude, let me draw your attention to an enlargement of an Italian stamp commemorating A Avogadro. The statement reads: "Equal volumes of gas in the same temperature and pressure conditions contain the same number of molecules". He simply stated the existence of such a number, leaving us with the pleasure of measuring it.

  20. 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

  1. 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.

  2. Influence of gas pressure on high-order-harmonic generation of Ar and Ne

    SciTech Connect

    Wang Guoli; Jin Cheng; Le, Anh-Thu; Lin, C. D.

    2011-11-15

    We study the effect of gas pressure on the generation of high-order harmonics where harmonics due to individual atoms are calculated using the recently developed quantitative rescattering theory, and the propagation of the laser and harmonics in the medium is calculated by solving the Maxwell's wave equation. We illustrate that the simulated spectra are very sensitive to the laser focusing conditions at high laser intensity and high pressure since the fundamental laser field is severely reshaped during the propagation. By comparing the simulated results with several experiments we show that the pressure dependence can be qualitatively explained. The lack of quantitative agreement is tentatively attributed to the failure of the complete knowledge of the experimental conditions.

  3. 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.

  4. DC Linked Hybrid Generation System with an Energy Storage Device including a Photo-Voltaic Generation and a Gas Engine Cogeneration for Residential Houses

    NASA Astrophysics Data System (ADS)

    Lung, Chienru; Miyake, Shota; Kakigano, Hiroaki; Miura, Yushi; Ise, Toshifumi; Momose, Toshinari; Hayakawa, Hideki

    For the past few years, a hybrid generation system including solar panel and gas cogeneration is being used for residential houses. Solar panels can generate electronic power at daytime; meanwhile, it cannot generate electronic power at night time. But the power consumption of residential houses usually peaks in the evening. The gas engine cogeneration system can generate electronic power without such a restriction, and it also can generate heat power to warm up house or to produce hot water. In this paper, we propose the solar panel and gas engine co-generation hybrid system with an energy storage device that is combined by dc bus. If a black out occurs, the system still can supply electronic power for special house loads. We propose the control scheme for the system which are related with the charging level of the energy storage device, the voltage of the utility grid which can be applied both grid connected and stand alone operation. Finally, we carried out some experiments to demonstrate the system operation and calculation for loss estimation.

  5. Generation and exploration of the Spin-Orbit coupled Bose gas

    NASA Astrophysics Data System (ADS)

    Pan, Jian-Wei

    2013-03-01

    To generate an artificial gauge field with ultracold quantum gas becomes a very hot topic in last few years and will continue to be attractive for ultracold atomic and condensed matter physics in the coming future. Many interesting and important topics such as Fractional Quantum Hall effect, Spin-orbit coupling and Topological insulator are connected to this topic very closely. Here we present our recent experimental progress of the synthesized gauge potential and the spin-orbit coupled Bose-Einstein condensate (BEC) in optical dipole trap. Raman coupling technique and a bias magnetic field is applied to tune the structure of the gauge potential and spin-orbit coupling. Several fundamental properties of spin-orbit coupled BEC is experimentally studied including the properties of collective dipole oscillation, the stability of excited dressed state, the critical temperature of spin-orbit coupled Bose gas and the formation of magnetic order during evaporative cooling. These studies enrich the knowledge of this field and further explorations are also in planning.

  6. Generation and orientation of organoxenon molecule H-Xe-CCH in the gas phase

    SciTech Connect

    Poterya, Viktoriya; Votava, Ondrej; Farnik, Michal; Oncak, Milan; Slavicek, Petr; Buck, Udo; Friedrich, Bretislav

    2008-03-14

    We report on the first observation of the organoxenon HXeCCH molecule in the gas phase. This molecule has been prepared in a molecular beam experiment by 193 nm photolysis of an acetylene molecule on Xe{sub n} clusters (n{approx_equal}390). Subsequently the molecule has been oriented via the pseudo-first-order Stark effect in a strong electric field of the polarized laser light combined with the weak electrostatic field in the extraction region of a time-of-flight spectrometer. The experimental evidence for the oriented molecule has been provided by measurements of its photodissociation. For comparison, photolysis of C{sub 2}H{sub 2} on Ar{sub n} clusters (n{approx_equal}280) has been measured. Here the analogous rare gas molecule HArCCH could not be generated. The interpretation of our experimental findings has been supported by ab initio calculations. In addition, the experiment together with the calculations reveals information on the photochemistry of the HXeCCH molecule. The 193 nm radiation excites the molecule predominantly into the 2 {sup 1}{sigma}{sup +} state, which cannot dissociate the Xe-H bond directly, but the system evolves along the Xe-C coordinate to a conical intersection of a slightly nonlinear configuration with the dissociative 1 {sup 1}{pi} state, which then dissociates the Xe-H bond.

  7. Generation and orientation of organoxenon molecule H-Xe-CCH in the gas phase

    NASA Astrophysics Data System (ADS)

    Poterya, Viktoriya; Votava, Ondřej; Fárník, Michal; Ončák, Milan; Slavíček, Petr; Buck, Udo; Friedrich, Břetislav

    2008-03-01

    We report on the first observation of the organoxenon HXeCCH molecule in the gas phase. This molecule has been prepared in a molecular beam experiment by 193nm photolysis of an acetylene molecule on Xen clusters (n¯≈390). Subsequently the molecule has been oriented via the pseudo-first-order Stark effect in a strong electric field of the polarized laser light combined with the weak electrostatic field in the extraction region of a time-of-flight spectrometer. The experimental evidence for the oriented molecule has been provided by measurements of its photodissociation. For comparison, photolysis of C2H2 on Arn clusters (n¯≈280) has been measured. Here the analogous rare gas molecule HArCCH could not be generated. The interpretation of our experimental findings has been supported by ab initio calculations. In addition, the experiment together with the calculations reveals information on the photochemistry of the HXeCCH molecule. The 193nm radiation excites the molecule predominantly into the 2Σ+1 state, which cannot dissociate the Xe-H bond directly, but the system evolves along the Xe-C coordinate to a conical intersection of a slightly nonlinear configuration with the dissociative 1Π1 state, which then dissociates the Xe-H bond.

  8. Public health benefits of strategies to reduce greenhouse-gas emissions: low-carbon electricity generation.

    PubMed

    Markandya, Anil; Armstrong, Ben G; Hales, Simon; Chiabai, Aline; Criqui, Patrick; Mima, Silvana; Tonne, Cathryn; Wilkinson, Paul

    2009-12-12

    In this report, the third in this Series on health and climate change, we assess the changes in particle air pollution emissions and consequent effects on health that are likely to result from greenhouse-gas mitigation measures in the electricity generation sector in the European Union (EU), China, and India. We model the effect in 2030 of policies that aim to reduce total carbon dioxide (CO(2)) emissions by 50% by 2050 globally compared with the effect of emissions in 1990. We use three models: the POLES model, which identifies the distribution of production modes that give the desired CO(2) reductions and associated costs; the GAINS model, which estimates fine particulate matter with aerodynamic diameter 2.5 microm or less (PM(2.5)) concentrations; and a model to estimate the effect of PM(2.5) on mortality on the basis of the WHO's Comparative Risk Assessment methods. Changes in modes of production of electricity to reduce CO(2) emissions would, in all regions, reduce PM(2.5) and deaths caused by it, with the greatest effect in India and the smallest in the EU. Health benefits greatly offset costs of greenhouse-gas mitigation, especially in India where pollution is high and costs of mitigation are low. Our estimates are approximations but suggest clear health gains (co-benefits) through decarbonising electricity production, and provide additional information about the extent of such gains.

  9. 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.

  10. Slowing of Femtosecond Laser-Generated Nanoparticles in a Background Gas

    DOE PAGES

    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

  11. Sound waves generated due to the absorption of a pulsed electron beam in gas

    NASA Astrophysics Data System (ADS)

    Pushkarev, A. I.; Pushkarev, M. A.; Remnev, G. E.

    2002-03-01

    The results of an experimental investigation of acoustic vibrations (their frequency, amplitude, and attenuation coefficient) generated in a gas mixture as a result of the injection of a high-current pulsed electron beam into a closed reactor are presented. It is shown that the change in the phase composition of the initial mixture under the action of the electron beam leads to a change in the frequency of the sound waves and to an increase in the attenuation coefficient. By measuring the change in frequency, it is possible to evaluate with sufficient accuracy (about 2%) the degree of conversion of the initial products in the plasmochemical process. Relations describing the dependence of the sound energy attenuation coefficient on the size of the reactor and on the thermal and physical properties of the gases under study are derived. It is shown that a simple experimental setup measuring the parameters of acoustic waves can be used for monitoring the plasmochemical processes initiated by a pulsed excitation of a gas mixture.

  12. 1D simulation of runaway electrons generation in pulsed high-pressure gas discharge

    NASA Astrophysics Data System (ADS)

    Kozhevnikov, V. Yu.; Kozyrev, A. V.; Semeniuk, N. S.

    2015-10-01

    The results of theoretical modelling of runaway electron generation in the high-pressure nanosecond pulsed gas discharge are presented. A novel hybrid model of gas discharge has been successfully built. Hydrodynamic and kinetic approaches are used simultaneously to describe the dynamics of different components of low-temperature discharge plasma. To consider motion of ions and low-energy (plasma) electrons the corresponding equations of continuity with drift-diffusion approximation are used. To describe high-energy (runaway) electrons the Boltzmann kinetic equation is included. As a result of the simulation we obtained spatial and temporal distributions of charged particles and electric field in a pulsed discharge. Furthermore, the energy spectra calculated runaway electrons in different cross-sections, particularly, the discharge gap in the anode plane. It is shown that the average energy of fast electrons (in eV) in the anode plane is usually slightly higher than the instantaneous value of the applied voltage to the gap (in V).

  13. 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.

  14. 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.

  15. Composition, preparation, and gas generation results from simulated wastes of Tank 241-SY-101

    SciTech Connect

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

    1994-08-01

    This document reviews the preparation and composition of simulants that have been developed to mimic the wastes temporarily stored in Tank 241-SY-101 at Hanford. The kinetics and stoichiometry of gases that are generated using these simulants are also compared, considering the roles of hydroxide, chloride, and transition metal ions; the identities of organic constituents; and the effects of dilution, radiation, and temperature. Work described in this report was conducted for the Flammable Gas Safety Program at Pacific Northwest Laboratory, (a) whose purpose is to develop information that is necessary to mitigate potential safety hazards associated with waste tanks at the Hanford Site. The goal of this research and of related efforts at the Georgia Institute of Technology (GIT), Argonne National Laboratory (ANL), and Westinghouse Hanford Company (WHC) is to determine the thermal and thermal/radiolytic mechanisms by which flammable and other gases are produced in Hanford wastes, emphasizing those stored in Tank 241-SY-101. A variety of Tank 241-SY-101 simulants have been developed to date. The use of simulants in laboratory testing activities provides a number of advantages, including elimination of radiological risks to researchers, lower costs associated with experimentation, and the ability to systematically alter simulant compositions to study the chemical mechanisms of reactions responsible for gas generation. The earliest simulants contained the principal inorganic components of the actual waste and generally a single complexant such as N-(2-hydroxyethyl) ethylenediaminetriacetic acid (HEDTA) or ethylenediaminetriacetic acid (EDTA). Both homogeneous and heterogeneous compositional forms were developed. Aggressive core sampling and analysis activities conducted during Windows C and E provided information that was used to design new simulants that more accurately reflected major and minor inorganic components.

  16. 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

  17. 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.

  18. 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

  19. 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

  20. Evaluation of gas turbine and gasifier-based power generation system

    NASA Astrophysics Data System (ADS)

    Zhu, Yunhua

    As a technology in early commercial phase, research work is needed to provide evaluation of the effects of alternative designs and technology advances and provide guidelines for development direction of Integrated Gasification Combined Cycle (IGCC) technology in future. The objective of this study is to evaluate the potential pay-offs as well as risks of technological infeasibility for IGCC systems and to provide insight regarding desired strategies for the future development of advanced IGCC systems. Texaco gasifier process is widely used in power generation. A process simulation model for a base Texaco gasifier-based IGCC system, including performance (e.g., efficiency), emissions, and cost, was implemented in the ASPEN Plus. The model is calibrated and verified based on other design studies. To find out the implications of the effects of coal compositions on IGCC plant, the Illinois No.6, Pittsburgh No.8, and West Kentucky coal are selected for comparison. The results indicate that the ash content and sulfur content of coal have effects on performance, SO2 emissions, and capital cost of IGCC system. As the main component for power generation, the effects of the most advanced Frame 7H and the current widely used Frame 7F gas turbine combined cycles on IGCC system were evaluated. The results demonstrated the IGCC system based on 7H gas turbine (IGCC-7H) has higher efficiency, lower CO2 emission, and lower cost of electricity than the 7FA based system (IGCC-7FA). A simplified spreadsheet model is developed for estimating mass and energy balance of gas turbine combined cycle. It demonstrated that an accurate and sensitive model can be implemented in a spreadsheet. This study implicated the ability to do desktop simulations to support policy analysis. Uncertainty analysis is implemented to find out the risks associated with the IGCC systems, i.e., there is about 80% probability that the uncertain results of the efficiency of IGCC-7FA system are lower than the

  1. 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.

  2. 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.

  3. Development of a hydrogen generator based on the partial oxidation of natural gas integrated with PEFC

    SciTech Connect

    Recupero, V.; Pino, L.; Di Leonardo, R.; Lagana, M.

    1998-12-31

    As is well known, the most acknowledged process for generation of hydrogen for fuel cells is based upon the steam reforming of methane or natural gas. A valid alternative could be a process based on partial oxidation of methane, since the process is mildly exothermic and therefore not energy intensive. Consequently, great interest is expected from conversion of methane into syngas, if an autothermal, low energy intensive, compact and reliable process could be developed. This paper covers the activities, performed by CNR Institute Transformation and Storage of Energy, Messina, Italy, on theoretical and experimental studies for a compact hydrogen generator, via catalytic selective partial oxidation of methane, integrated with a PEFC (Polymer Electrolyte Fuel Cell). In particular, the project focuses the attention on methane partial oxidation via heterogeneous selective catalysts, in order to: demonstrate the basic Catalytic Selective Partial Oxidation of Methane (CSPOM) technology in a subscale prototype, equivalent to a nominal output of 5 kWe; develop the CSPOM technology for its application in electric energy production by means of fuel cells; assess, by a balance of plant analysis, and a techno-economic evaluation, the potential benefits of the CSPOM for different categories of fuel cells.

  4. Generation Performance of a Fuel Cell Using Hydrogen and Di-methyl-ether (DME) Mixed Gas

    NASA Astrophysics Data System (ADS)

    Haraguchi, Tadao; Watanabe, Takashi; Yamashita, Masahiro; Tsutsumi, Yasuyuki; Yamashita, Susumu

    Di-methyl-ether (DME), an oxygenated hydrocarbon, can facilitate hydrogen manufacture by steam reforming reaction at low temperature. Methanol and DME steam reforming at 250-300°C, reforming DME into hydrogen, can be performed easily with small-scale and simple equipment. Whether the hydrogen output from the reformer for supply to the fuel cell includes DME, and how this affects the generation performance has yet to be confirmed. The purpose of this paper is to investigate the supply of a fuel cell with mixtures of DME and H2 in varying proportions and to clarify the effect on generation performance. Conclusions are as follows: (1) For a supply of DME and H2 mixed gas, DME is consumed after the H2 is consumed. By comparing the experimental values with theoretical values of consumption of pure H2, a mixture of DME and H2, and pure DME, it proved to be possible to roughly predict the experimental values by calculation. (2) The voltage value moved to near the DME voltage after the H2 was consumed, the current density increased after the H2 was consumed. (3) During continuous running the voltage load was observed to fluctuate.

  5. 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

  6. 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.

  7. Cell-surface area codes: mobile-element related gene switches generate precise and heritable cell-surface displays of address molecules that are used for constructing embryos.

    PubMed

    Dreyer, W J; Roman-Dreyer, J

    1999-01-01

    We present an updated area code hypothesis supporting the proposal that cell surface display of seven-transmembrane olfactory receptors, protocadherins and other cell surface receptors provide codes that enable cells to find their correct partners as they sculpture embryos. The genetic mechanisms that program the expression of such displays have been largely unknown until very recently. However, increasing evidence now suggests that precise developmental control of the expression of these genes during embryogenesis is achieved in part by permanent and heritable changes in DNA. Using the developing immune system as a model, we discuss two different types of developmentally programmed genetic switches, each of which relies on recombination mechanisms related to mobile elements. We review new evidence suggesting the involvement of mobile element related switch mechanisms in the generation of protocadherin molecules, and their possible involvement in the control of expressions of olfactory receptors. As both recombinase and reverse transcriptase mechanisms play a role in the switching of the immunoglobulin genes, we searched the databases of expressed sequence tags (dbEST) for expression of related genes in other tissues. We present data revealing that transposases and reverse transcriptases are widely expressed in most tissues. We also searched these databases for expression of env (envelope) gene products, stimulated by provocative results suggesting that these molecules might function as cellular address receptors. We found that env genes are also expressed in large numbers in normal human tissues. One must assume that these three different types of mobile-element-related messenger RNA molecules (transposases, reverse transcriptases, and env proteins) are expressed for use in functions of value in the various tissues and have been preserved in the genome because of their selective advantages. We conclude that it is possible that many specific cell lineage decisions

  8. Reductions in greenhouse gas (GHG) generation and energy consumption in wastewater treatment plants.

    PubMed

    Yerushalmi, L; Ashrafi, O; Haghighat, F

    2013-01-01

    Greenhouse gas (GHG) emission and energy consumption by on-site and off-site sources were estimated in two different wastewater treatment plants that used physical-chemical or biological processes for the removal of contaminants, and an anaerobic digester for sludge treatment. Physical-chemical treatment processes were used in the treatment plant of a locomotive repair factory that processed wastewater at 842 kg chemical oxygen demand per day. Approximately 80% of the total GHG emission was related to fossil fuel consumption for energy production. The emission of GHG was reduced by 14.5% with the recovery of biogas that was generated in the anaerobic digester and its further use as an energy source, replacing fossil fuels. The examined biological treatment system used three alternative process designs for the treatment of effluents from pulp and paper mills that processed wastewater at 2,000 kg biochemical oxygen demand per day. The three designs used aerobic, anaerobic, or hybrid aerobic/anaerobic biological processes for the removal of carbonaceous contaminants, and nitrification/denitrification processes for nitrogen removal. Without the recovery and use of biogas, the aerobic, anaerobic, and hybrid treatment systems generated 3,346, 6,554 and 7,056 kg CO(2)-equivalent/day, respectively, while the generated GHG was reduced to 3,152, 6,051, and 6,541 kg CO(2)-equivalent/day with biogas recovery. The recovery and use of biogas was shown to satisfy and exceed the energy needs of the three examined treatment plants. The reduction of operating temperature of the anaerobic digester and anaerobic reactor by 10°C reduced energy demands of the treatment plants by 35.1, 70.6 and 62.9% in the three examined treatment systems, respectively.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. An Integrated microfluidic platform for liquid droplet in gas flow generation with in liquid flow collection and manipulation

    NASA Astrophysics Data System (ADS)

    Tirandazi, Pooyan; Hidrovo, Carlos H.

    2016-11-01

    Discretization of biological samples and chemical reactions within digital droplets is a powerful technique which has rapidly emerged in many biochemical syntheses. The ability to generate, manipulate, and monitor millions of microdroplets in a short time provides great potential for high throughput screening and detection in microbiology. Here we report a microfluidic device for the formation of uniform microdroplets (50 μm-100 μm) using a high speed gas as the continuous phase. Gas-borne droplets are generated in a chip-based flow-focusing device fabricated in PDMS, and travel along the gaseous microchannel and are subsequently captured within a second liquid phase. The droplets are then transferred and collected in a minichamber and move into the manipulation section for further processing operations on the drops. All these steps are performed automatically in a single multilayer chip. This integrated microfluidic platform for generation, collection, and manipulation of the droplets provides great opportunities for monitoring and detection of gas-analytes. Utilizing the generated picoliter airborne droplets feature lower reaction times and higher transfer rates as compared to conventional air sampling techniques. Thus, it can greatly facilitate the investigation of airborne analytes by interrogation of the digital droplets using different analytical techniques. Furthermore, the presented liquid-in-gas generation method can be utilized for production of oil-free microparticles and microcapsules used in the food industry and for drug delivery.

  14. 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

  15. 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.

  16. 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

  17. Enhanced late gas generation potential of petroleum source rocks via recombination reactions: Evidence from the Norwegian North Sea

    NASA Astrophysics Data System (ADS)

    Erdmann, Michael; Horsfield, Brian

    2006-08-01

    Gas generation in the deep reaches of sedimentary basins is usually considered to take place via the primary cracking of short alkyl groups from overmature kerogen or the secondary cracking of petroleum. Here, we show that recombination reactions ultimately play the dominant role in controlling the timing of late gas generation in source rocks which contain mixtures of terrigeneous and marine organic matter. These reactions, taking place at low levels of maturation, result in the formation of a thermally stable bitumen, which is the major source of methane at very high maturities. The inferences come from pyrolysis experiments performed on samples of the Draupne Formation (liptinitic Type II kerogen) and Heather Formation (mixed marine-terrigeneous Type III kerogen), both Upper Jurassic source rocks stemming from the Norwegian northern North Sea Viking Graben system. Non-isothermal closed system micro scale sealed vessel (MSSV) pyrolysis, non-isothermal open system pyrolysis and Rock Eval type pyrolysis were performed on the solvent extracted, concentrated kerogens of the two immature samples. The decrease of C 6+ products in the closed system MSSV pyrolysis provided the basis for the calculation of secondary gas (C 1-5) formation. Subtraction of the calculated secondary gas from the total observed gas yields a "remaining" gas. In the case of the Draupne Formation this is equivalent to primary gas cracked directly from the kerogen, as detected by a comparison with multistep open pyrolysis data. For the Heather Formation the calculated remaining gas formation profile is initially attributable to primary gas but there is a second major gas pulse at very high temperature (>550 °C at 5.0 K min -1) that is not primary. This has been explained by a recondensation process where first formed high molecular weight compounds in the closed system yield a macromolecular material that undergoes secondary cracking at elevated temperatures. The experiments provided the input for

  18. Onboard Plasmatron Generation of Hydrogen rich Gas for Diesel Engine Exhaust Aftertreatment and Other Applications

    SciTech Connect

    Bromberg, L.; Cohn, D.R.; Heywood,J.; Rabinovich, A.

    2002-08-25

    Plasmatron reformers can provide attractive means for conversion of diesel fuel into hydrogen rich gas. The hydrogen rich gas can be used for improved NOx trap technology and other aftertreatment applications.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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%.

  4. Thermal and Radiolytic Gas Generation Tests on Material from Tanks 241-U-103, 241-AW-101, 241-S-106, and 241-S-102: Status Report

    SciTech Connect

    King, C.M.; Bryan, S.A.

    1999-06-17

    This report summarizes progress in evaluating thermal and radiolytic flammable gas generation in actual Hanford single-shell tank wastes. The work described was conducted at Pacific Northwest National Laboratory (PNNL) for the Flammable Gas Safety Project, whose purpose is to develop information to support DE&S Hanford (DESH) and Project Management Hanford Contract (PHMC) subcontractors in their efforts to ensure the safe interim storage of wastes at the Hanford Site. This work is related to gas generation studies performed by Numatec Hanford Corporation (formerly Westinghouse Hanford Company). This report describes the results of laboratory tests of gas generation from actual convective layer wastes from Tank 241-U-103 under thermal and radiolytic conditions. Accurate measurements of gas generation rates from highly radioactive tank wastes are needed to assess the potential for producing and storing flammable gases within the tanks. The gas generation capacity of the waste in Tank 241-U-103 is a high priority for the Flammable Gas Safety Program due to its potential for accumulating gases above the flammability limit (Johnson et al, 1997). The objective of this work was to establish the composition of gaseous degradation products formed in actual tank wastes by thermal and radiolytic processes as a function of temperature. The gas generation tests on Tank 241-U-103 samples focused first on the effect of temperature on the composition and rate of gas generation Generation rates of nitrogen, nitrous oxide, methane, and hydrogen increased with temperature, and the composition of the product gas mixture varied with temperature.

  5. 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.

  6. 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.

  7. Fabrication of stainless steel mesh gas diffusion electrode for power generation in microbial fuel cell.

    PubMed

    You, Shi-Jie; Wang, Xiu-Heng; Zhang, Jin-Na; Wang, Jing-Yuan; Ren, Nan-Qi; Gong, Xiao-Bo

    2011-01-15

    This study reports the fabrication of a new membrane electrode assembly by using stainless steel mesh (SSM) as raw material and its effectiveness as gas diffusion electrode (GDE) for electrochemical oxygen reduction in microbial fuel cell (MFC). Based on feeding glucose (0.5 g L(-1)) substrate to a single-chambered MFC, power generation using SSM-based GDE was increased with the decrease of polytetrafluoroethylene (PTFE) content applied during fabrication, reaching the optimum power density of 951.6 mW m(-2) at 20% PTFE. Repeatable cell voltage of 0.51 V (external resistance of 400 Ω) and maximum power density of 951.6 mW m(-2) produced for the MFC with SSM-based GDE are comparable to that of 0.52 V and 972.6 mW m(-2), respectively obtained for the MFC containing typical carbon cloth (CC)-made GDE. Besides, Coulombic efficiency (CE) is found higher for GDE (SSM or CC) with membrane assembly than without, which results preliminarily from the mitigation of Coulombic loss being associated with oxygen diffusion and substrate crossover. This study demonstrates that with its good electrical conductivity and much lower cost, the SSM-made GDE suggests a promising alternative as efficient and more economically viable material to conventional typical carbon for power production from biomass in MFC.

  8. Effect of process parameters on greenhouse gas generation by wastewater treatment plants.

    PubMed

    Yerushalmi, L; Shahabadi, M Bani; Haghighat, F

    2011-05-01

    The effect of key process parameters on greenhouse gas (GHG) emission by wastewater treatment plants was evaluated, and the governing parameters that exhibited major effects on the overall on- and off-site GHG emissions were identified. This evaluation used aerobic, anaerobic, and hybrid anaerobic/aerobic treatment systems with food processing industry wastewater. The operating temperature of anaerobic sludge digester was identified to have the highest effect on GHG generation in the aerobic treatment system. The total GHG emissions of 2694 kg CO2e/d were increased by 72.5% with the increase of anaerobic sludge digester temperature from 20 to 40 degrees C. The operating temperature of the anaerobic reactor was the dominant controlling parameter in the anaerobic and hybrid treatment systems. Raising the anaerobic reactor's temperature from 25 to 40 degrees C increased the total GHG emissions from 5822 and 6617 kg CO2e/d by 105.6 and 96.5% in the anaerobic and hybrid treatment systems, respectively.

  9. Numerical analysis of heat transfer in the exhaust gas flow in a diesel power generator

    NASA Astrophysics Data System (ADS)

    Brito, C. H. G.; Maia, C. B.; Sodré, J. R.

    2016-09-01

    This work presents a numerical study of heat transfer in the exhaust duct of a diesel power generator. The analysis was performed using two different approaches: the Finite Difference Method (FDM) and the Finite Volume Method (FVM), this last one by means of a commercial computer software, ANSYS CFX®. In FDM, the energy conservation equation was solved taking into account the estimated velocity profile for fully developed turbulent flow inside a tube and literature correlations for heat transfer. In FVM, the mass conservation, momentum, energy and transport equations were solved for turbulent quantities by the K-ω SST model. In both methods, variable properties were considered for the exhaust gas composed by six species: CO2, H2O, H2, O2, CO and N2. The entry conditions for the numerical simulations were given by experimental data available. The results were evaluated for the engine operating under loads of 0, 10, 20, and 37.5 kW. Test mesh and convergence were performed to determine the numerical error and uncertainty of the simulations. The results showed a trend of increasing temperature gradient with load increase. The general behaviour of the velocity and temperature profiles obtained by the numerical models were similar, with some divergence arising due to the assumptions made for the resolution of the models.

  10. Reversible solid oxide fuel cell for natural gas/renewable hybrid power generation systems

    NASA Astrophysics Data System (ADS)

    Luo, Yu; Shi, Yixiang; Zheng, Yi; Cai, Ningsheng

    2017-02-01

    Renewable energy (RE) is expected to be the major part of the future energy. Presently, the intermittence and fluctuation of RE lead to the limitation of its penetration. Reversible solid oxide fuel cell (RSOFC) as the energy storage device can effectively store the renewable energy and build a bidirectional connection with natural gas (NG). In this paper, the energy storage strategy was designed to improve the RE penetration and dynamic operation stability in a distributed system coupling wind generators, internal combustion engine, RSOFC and lithium-ion batteries. By compromising the relative deviation of power supply and demand, RE penetration, system efficiency and capacity requirement, the strategy that no more than 36% of the maximum wind power output is directly supplied to users and the other is stored by the combination of battery and reversible solid oxide fuel cell is optimal for the distributed system. In the case, the RE penetration reached 56.9% and the system efficiency reached 55.2%. The maximum relative deviation of power supply and demand is also lower than 4%, which is significantly superior to that in the wind curtailment case.

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. Size Exclusion High Performance Liquid Chromatography Analysis of a Cellulose Acetate-Ammonium Nitrate Gas Generator Propellant

    DTIC Science & Technology

    1982-06-02

    Problems involving mix-to-mix reproducibility for TAL-704 (a Talley Industries of Arizona cellulose acetate -ammonium nitrate gas generator propellant...correspondingly similar retention volumes (measured by both ultraviolet and refractive index detectors). These peaks were mainly attributed to cellulose acetate (5.51

  16. 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

  17. 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.

  18. Evaluation of the British Gas Corporation/Lurgi slagging gasifier in gasification-combined-cycle power generation. Final report

    SciTech Connect

    delaMora, J.A.; Grisso, J.R.; Klumpe, H.W.; Musso, A.; Roszkowski, T.R.; Thompson, B.H.; Lienhard, H.; Beyer, T.

    1985-03-01

    Plant designs, performance data, cost estimates, and bus-bar power costs were developed for a nominal 500-MW integrated coal gasification, combined-cycle power plant. The British Gas/Lurgi slagging, fixed-bed gasifier was employed to produce a clean fuel gas from coal. The clean fuel gas was fired in near-term, advanced technology combustion gas turbines operating at combustor temperatures of 2200/sup 0/F. Gas turbine exhausts were used to produce steam that was employed in a superheat/reheat main steam turbine generator to produce additional power. Duct burners and external combustors were investigated for the purpose of firing any fuel gas available in excess of that consumed by the gas turbines. The results of the study indicate that the power plant has the potential to provide base-load electricity at a cost that is 10% to 15% lower than the cost of electricity produced by a conventional coal-steam plant. In addition, the plant has the capability for producing very low-cost peak and intermediate load electricity. Harmful emissions from the plant would be considerably reduced in quantity relative to conventional coal-fired plants. 24 figures, 43 tables.

  19. Palladium(II)‐Catalysed Aminocarbonylation of Terminal Alkynes for the Synthesis of 2‐Ynamides: Addressing the Challenges of Solvents and Gas Mixtures

    PubMed Central

    Hughes, N. Louise; Brown, Clare L.; Irwin, Andrew A.; Cao, Qun

    2017-01-01

    Abstract 2‐Ynamides can be synthesised through PdII catalysed oxidative carbonylation, utilising low catalyst loadings. A variety of alkynes and amines can be used to afford 2‐ynamides in high yields, whilst overcoming the drawbacks associated with previous oxidative methods, which rely on dangerous solvents and gas mixtures. The use of [NBu4]I allows the utilisation of the industrially recommended solvent ethyl acetate. O2 can be used as the terminal oxidant, and the catalyst can operate under safer conditions with low O2 concentrations. PMID:27906507

  20. Palladium(II)-Catalysed Aminocarbonylation of Terminal Alkynes for the Synthesis of 2-Ynamides: Addressing the Challenges of Solvents and Gas Mixtures.

    PubMed

    Hughes, N Louise; Brown, Clare L; Irwin, Andrew A; Cao, Qun; Muldoon, Mark J

    2017-02-22

    2-Ynamides can be synthesised through Pd(II) catalysed oxidative carbonylation, utilising low catalyst loadings. A variety of alkynes and amines can be used to afford 2-ynamides in high yields, whilst overcoming the drawbacks associated with previous oxidative methods, which rely on dangerous solvents and gas mixtures. The use of [NBu4 ]I allows the utilisation of the industrially recommended solvent ethyl acetate. O2 can be used as the terminal oxidant, and the catalyst can operate under safer conditions with low O2 concentrations.

  1. 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.

  2. 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

  3. 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.

  4. Evidence for iC3 generation during cardiopulmonary bypass as the result of blood-gas interaction.

    PubMed Central

    Pekna, M; Nilsson, L; Nilsson-Ekdahl, K; Nilsson, U R; Nilsson, B

    1993-01-01

    Earlier we have shown that iC3 is generated at the blood-gas interface in vitro and that the generation of this molecule is independent of complement activation and the composition of the gas. In order to investigate whether iC3 is also generated during cardiopulmonary bypass where blood comes into contact with oxygen bubbles, two bubble oxygenators were incubated at 37 degrees C with human heparinized blood. A continuous increase in the level of iC3 was shown in the oxygen-perfused bubble oxygenator (up to 100 nmol/l after 180 min) in contrast to the unbubbled control. Similarly, in plasma drawn from patients undergoing cardiopulmonary bypass using either bubble or membrane oxygenators, the levels of iC3 were shown to increase continuously during the operation. Furthermore, this form of C3 was found to be susceptible to cleavage by factor I. The formation of iC3 at the blood-gas interface in vivo could be a mechanism by which gas bubbles induce clinical manifestations associated with complement activation, e.g. during cardiopulmonary bypass, adult respiratory distress syndrome and decompression sickness. Images Fig. 3 Fig. 4 PMID:8443963

  5. Comparative life-cycle air emissions of coal, domestic natural gas, LNG, and SNG for electricity generation.

    PubMed

    Jaramillo, Paulina; Griffin, W Michael; Matthews, H Scott

    2007-09-01

    The U.S. Department of Energy (DOE) estimates that in the coming decades the United States' natural gas (NG) demand for electricity generation will increase. Estimates also suggest that NG supply will increasingly come from imported liquefied natural gas (LNG). Additional supplies of NG could come domestically from the production of synthetic natural gas (SNG) via coal gasification-methanation. The objective of this study is to compare greenhouse gas (GHG), SOx, and NOx life-cycle emissions of electricity generated with NG/LNG/SNG and coal. This life-cycle comparison of air emissions from different fuels can help us better understand the advantages and disadvantages of using coal versus globally sourced NG for electricity generation. Our estimates suggest that with the current fleet of power plants, a mix of domestic NG, LNG, and SNG would have lower GHG emissions than coal. If advanced technologies with carbon capture and sequestration (CCS) are used, however, coal and a mix of domestic NG, LNG, and SNG would have very similar life-cycle GHG emissions. For SOx and NOx we find there are significant emissions in the upstream stages of the NG/ LNG life-cycles, which contribute to a larger range in SOx and NOx emissions for NG/LNG than for coal and SNG.

  6. Comparative life-cycle air emissions of coal, domestic natural gas, LNG, and SNG for electricity generation

    SciTech Connect

    Paulina Jaramillo; W. Michael Griffin; H. Scott Matthews

    2007-09-15

    The U.S. Department of Energy (DOE) estimates that in the coming decades the United States' natural gas (NG) demand for electricity generation will increase. Estimates also suggest that NG supply will increasingly come from imported liquefied natural gas (LNG). Additional supplies of NG could come domestically from the production of synthetic natural gas (SNG) via coal gasification-methanation. The objective of this study is to compare greenhouse gas (GHG), SOx, and NOx life-cycle emissions of electricity generated with NG/LNG/SNG and coal. This life-cycle comparison of air emissions from different fuels can help us better understand the advantages and disadvantages of using coal versus globally sourced NG for electricity generation. Our estimates suggest that with the current fleet of power plants, a mix of domestic NG, LNG, and SNG would have lower GHG emissions than coal. If advanced technologies with carbon capture and sequestration (CCS) are used, however, coal and a mix of domestic NG, LNG, and SNG would have very similar life-cycle GHG emissions. For SOx and NOx we find there are significant emissions in the upstream stages of the NG/LNG life-cycles, which contribute to a larger range in SOx and NOx emissions for NG/LNG than for coal and SNG. 38 refs., 3 figs., 2 tabs.

  7. 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.

  8. 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

  9. 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

  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. 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.

  12. 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.

  13. 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.

  14. Enhanced high harmonic generation driven by high-intensity laser in argon gas-filled hollow core waveguide.

    PubMed

    Cassou, Kevin; Daboussi, Sameh; Hort, Ondrej; Guilbaud, Olivier; Descamps, Dominique; Petit, Stéphane; Mével, Eric; Constant, Eric; Kazamias, Sophie

    2014-07-01

    We show that a significant enhancement of the photon flux produced by high harmonic generation can be obtained through guided configuration at high laser intensity largely above the saturation intensity. We identify two regimes. At low pressure, we observe an intense second plateau in the high harmonic spectrum in argon. At relatively high pressure, complex interplay between strongly time-dependent ionization processes and propagation effects leads to important spectral broadening without loss of spectral brightness. We show that the relevant parameter for this physical process is the product of laser peak power by gas pressure. We compare source performances with high harmonic generation using a gas jet in loose focusing geometry and conclude that the source developed is a good candidate for injection devices such as seeded soft x-ray lasers or free electron lasers in the soft x-ray range.

  15. Development of methodologies for calculating greenhouse gas emissions from electricity generation for the California climate action registry

    SciTech Connect

    Price, Lynn; Marnay, Chris; Sathaye, Jayant; Murtishaw, Scott; Fisher, Diane; Phadke, Amol; Franco, Guido

    2002-04-01

    The California Climate Action Registry, which will begin operation in Fall 2002, is a voluntary registry for California businesses and organizations to record annual greenhouse gas emissions. Reporting of emissions in the Registry by a participant involves documentation of both ''direct'' emissions from sources that are under the entity's control and ''indirect'' emissions controlled by others. Electricity generated by an off-site power source is considered to be an indirect emission and must be included in the entity's report. Published electricity emissions factors for the State of California vary considerably due to differences in whether utility-owned out-of-state generation, non-utility generation, and electricity imports from other states are included. This paper describes the development of three methods for estimating electricity emissions factors for calculating the combined net carbon dioxide emissions from all generating facilities that provide electricity to Californians. We fi nd that use of a statewide average electricity emissions factor could drastically under- or over-estimate an entity's emissions due to the differences in generating resources among the utility service areas and seasonal variations. In addition, differentiating between marginal and average emissions is essential to accurately estimate the carbon dioxide savings from reducing electricity use. Results of this work will be taken into consideration by the Registry when finalizing its guidance for use of electricity emissions factors in calculating an entity's greenhouse gas emissions.

  16. 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.

  17. 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.

  18. A powerful electrohydrodynamic flow generated by a high-frequency dielectric barrier discharge in a gas

    SciTech Connect

    Nebogatkin, S. V.; Rebrov, I. E.; Khomich, V. Yu.; Yamshchikov, V. A.

    2016-01-15

    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.

  19. 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.

  20. Demonstration and Verification of a Turbine Power Generation System Utilizing Renewable Fuel: Landfill Gas

    DTIC Science & Technology

    2013-09-01

    landfills, facilities with anaerobic digesters for wastewater treatment, painting or printing operations, volatile organic compound (VOC) remediation...other similar fuel sources (e.g., digester gas). All assumptions and information sources are fully documented to give credibility to the results and...economics of the FP250 per se. For non-LFG fuel sources such as digester gas, extraction system costs are not relevant. Thus, Southern considers that

  1. 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.

  2. 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.

  3. 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 ...

  4. 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.

  5. Chemical gas-generating nanoparticles for tumor-targeted ultrasound imaging and ultrasound-triggered drug delivery.

    PubMed

    Min, Hyun Su; Son, Sejin; You, Dong Gil; Lee, Tae Woong; Lee, Jangwook; Lee, Sangmin; Yhee, Ji Young; Lee, Jaeyoung; Han, Moon Hee; Park, Jae Hyung; Kim, Sun Hwa; Choi, Kuiwon; Park, Kinam; Kim, Kwangmeyung; Kwon, Ick Chan

    2016-11-01

    Although there is great versatility of ultrasound (US) technologies in the real clinical field, one main technical challenge is the compromising of high quality of echo properties and size engineering of ultrasound contrast agents (UCAs); a high echo property is offset by reducing particle size. Herein, a new strategy for overcoming the dilemma by devising chemical gas (CO2) generating carbonate copolymer nanoparticles (Gas-NPs), which are clearly distinguished from the conventional gas-encapsulated micro-sized UCAs. More importantly, Gas-NPs could be readily engineered to strengthen the desirable in vivo physicochemical properties for nano-sized drug carriers with higher tumor targeting ability, as well as the high quality of echo properties for tumor-targeted US imaging. In tumor-bearing mice, anticancer drug-loaded Gas-NPs showed the desirable theranostic functions for US-triggered drug delivery, even after i.v. injection. In this regard, and as demonstrated in the aforementioned study, our technology could serve a highly effective platform in building theranostic UCAs with great sophistication and therapeutic applicability in tumor-targeted US imaging and US-triggered drug delivery.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. Evaluation of British Gas/Lurgi slagging gasifier for combined-cycle power generation

    SciTech Connect

    Roszkowski, T.R.; Klumpe, H.W.; Vierrath, H.; Beyer, T.; Thompson, B.H.

    1985-08-01

    Earlier studies by the Electric Power Research Institute were the basis for the study by British Gas/Lurgi of the slagging gasifier as a source of clean fuel gas for a gasification combined-cycle power plant. The current status of the technology of combustion gas turbine design and manufacture exhibits rapid change, providing additional incentive for the study. The goal was to develop a conceptual design to estimate the performance and the costs of capital, operations and maintenance, and electricity for a nominal 500 MW coal gasification combined-cycle power plant using slagging gasifiers. The authors describe the self-contained plant, and summarize performance, technology status of components, environmental aspects, and economics. 2 figures, 4 tables.

  13. Gas generation over plutonium oxides in the 94-1 shelf-life surveillance program.

    SciTech Connect

    Berg, J. M.; Harradine, D. M.; Hill, D. D.; McFarlan, James T.; Padilla, D. D.; Prenger, F. Coyne; Veirs, D. K.; Worl, L. A.

    2002-01-01

    The Department of Energy (DOE) is embarking upon a program to store large quantities of plutonium-bearing materials for up to fifty years. The Los Alamos National Laboratory Shelf Life Project was established to bound the behavior of plutonium-bearing material meeting the DOE 3013 Standard. The shelf life study monitors temperature, pressure and gas composition over oxide materials in a limited number of large-scale 3013 inner containers and in many small-scale containers. For the large-scale study, baseline plutonium oxides, oxides exposed to high-humidity atmospheres, and oxides containing chloride salt impurities are planned. The first large-scale container represents a baseline and contains dry plutonium oxide prepared according to the 3013 Standard. This container has been observed for pressure, temperature and gas compositional changes for less than a year. Results indicate that no detectable changes in pressure and gas composition are observed.

  14. Gas Generation over Plutonium Oxides in the 94-1 Shelf-Life Surveillance Program.

    SciTech Connect

    Berg, John M.; Hill, Dallas D.; McFarlan, James T.; Padilla, Dennis D.; Prenger, F. Coyne; Veirs, D. Kirk; Worl, Laura A.

    2003-08-13

    The Department of Energy (DOE) is embarking upon a program to store large quantities of plutoniumbearing materials for up to fifty years. The Los Alamos National Laboratory Shelf Life Project was established to bound the behavior of plutoniumbearing material meeting the DOE 3013 Standard. The shelf life study monitors temperature, pressure and gas composition over oxide materials in a limited number of large-scale 3013 inner containers and in many small-scale containers. For the large-scale study, baseline plutonium oxides, oxides exposed to high-humidity atmospheres, and oxides containing chloride salt impurities are planned. The first largescale container represents a baseline and contains dry plutonium oxide prepared according to the 3013 Standard. This container has been observed for pressure, temperature and gas compositional changes for less than a year. Results indicate that no detectable changes in pressure and gas composition are observed.

  15. Threshold curves obtained under various gaseous conditions for free radical generation by burst ultrasound - Effects of dissolved gas, microbubbles and gas transport from the air.

    PubMed

    Okada, Kengo; Kudo, Nobuki; Hassan, Mariame A; Kondo, Takashi; Yamamoto, Katsuyuki

    2009-04-01

    To understand the underlying concepts required for the determination of thresholds for free radical generation, effects of gas dissolution in and microbubble addition to sonicated solutions were investigated. Four solutions with different gaseous conditions, air-saturated and degassed solutions with and without microbubbles of 20 microm in diameter with shells, were studied in the presence of an air-liquid interface. These test solutions were exposed to 1 MHz ultrasound of 0.06 MPa(p-p) at various pulse durations (PDs) from 0.1 to 5 ms and pulse repetition frequencies from 0.1 to 2 kHz. Generation of free radicals was evaluated using the electron spin resonance (ESR) spin trapping method and starch-iodine method. Thresholds of duty ratio (DR) corresponding to temporal average intensity of ultrasound for free radical generation were significantly greater in degassed solutions than in air-saturated solutions. Microbubbles had no significant effects in air-saturated solutions but caused a slight decrease in the threshold in degassed solutions. In all of these results, the DR of a threshold curve against pulse repetition period (PRP) was not constant but linearly decreased with it, suggesting that a balance between bubble growth and shrinkage during the ON and OFF times of burst ultrasound is the primary parameter for the interpretation of thresholds. The effect of an air-liquid interface of the solution was also examined, and it was revealed that gas transport from the air is a predominant factor determining the amount of free radicals.

  16. 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...

  17. 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.

  18. Computational and experimental progress on laser-activated gas avalanche switches for broadband, high-power electromagnetic pulse generation

    SciTech Connect

    Mayhall, D.J.; Yee, J.H. ); Villa, F. )

    1990-09-01

    The gas avalanche switch, a high-voltage, picosecond-speed switch, has been proposed. The basic switch consists of pulse-charged electrodes, immersed in a high-pressure (7--800 atm) gas. An avalanche discharge is induced in the gas between the electrodes by ionization from a picosecond-scale laser pulse. The avalanching electrons move toward the anode, causing the applied voltage to collapse in picoseconds. This voltage collapse, if rapid enough, generates electromagnetic waves. A two-dimensional (2D), finite difference computer code solves Maxwell's equations for transverse magnetic modes for rectilinear electrodes between parallel plate conductors, along with electron conservation equations for continuity, momentum, and energy. Collision frequencies for ionization and momentum and energy transfer to neutral molecules are assumed to scale linearly with neutral pressure. Electrode charging and laser-driven electron deposition are assumed to be instantaneous. Code calculations are done for a pulse generator geometry, consisting of an 0.7 mm wide by 0.8 mm high, beveled, rectangular center electrode between grounded parallel plates at 2 mm spacing in air. 17 refs., 12 figs., 2 tabs.

  19. 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.

  20. 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.

  1. 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.

  2. Evidence for bacterially generated hydrocarbon gas in Canadian shield and fennoscandian shield rocks

    NASA Astrophysics Data System (ADS)

    Sherwood Lollar, B.; Frape, S. K.; Fritz, P.; Macko, S. A.; Welhan, J. A.; Blomqvist, R.; Lahermo, P. W.

    1993-12-01

    Hydrocarbon-rich gases found in crystalline rocks on the Canadian and Fennoscandian shields are isotopically and compositionally similar, suggesting that such gases are a characteristic feature of Precambrian Shield rocks. Gases occure in association with saline groundwaters and brines in pressurized "pockets" formed by sealed fracture systems within the host rocks. When released by drilling activities, gas pressures as high as 5000 kPa have been recorded. Typical gas flow rates for individual boreholes range from 0.25 L/min to 4 L/min. The highest concentrations of CH 4 are found in the deepest levels of the boreholes associated with CaNaCl (and NaCaCl) brines. N 2 is the second major component of the gases and with CH 4 accounts for up to 80 to >90 vol%. Higher hydrocarbon (C 2+) concentrations range from <1 to 10 vol.%, with C1/(C2 = C3) ratios from 10-1000. Isotopically the gases show a wide range of values overall ( σ 13C = -57.5 to -41.1%; σ D = -245 to -470‰ ) but a relatively tight cluster of values within each sampling locality. The Enonkoski Mine methanes are unique with σ 13C values between -65.4 and -67.3‰ and σD values between -297 and -347‰. The shield gases are not readily reconcilable with conventional theories of methanogenesis. The range of C1/(C2 + C3) ratios for the shield gases is too low to be consistent with an entirely bacterial origin. In addition, σD CH 4 values are in general too depleted in the heavy isotope to be produced by thermogenic methanogenesis or by secondary alteration processes such as bacterial oxidation or migration. However, isotopic and compositional evidence indicates that bacterially derived gas can account for a significant component of the gas at all shield sites. Conventional bacterial gas accounts for 75-94 vol% of the occurrences at Enonkoski Mine in Finland. At each of the other shield sites, bacterial gas can account for up to 30-50 vol% of the total gas accumulation. This study and other

  3. 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

  4. 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.

  5. Glucose-Responsive Sequential Generation of Hydrogen Peroxide and Nitric Oxide for Synergistic Cancer Starving-Like/Gas Therapy.

    PubMed

    Fan, Wenpei; Lu, Nan; Huang, Peng; Liu, Yi; Yang, Zhen; Wang, Sheng; Yu, Guocan; Liu, Yijing; Hu, Junkai; He, Qianjun; Qu, Junle; Wang, Tianfu; Chen, Xiaoyuan

    2017-01-24

    Glucose is a key energy supplier and nutrient for tumor growth. Herein, inspired by the glucose oxidase (GOx)-assisted conversion of glucose into gluconic acid and toxic H2 O2 , a novel treatment paradigm of starving-like therapy is developed for significant tumor-killing effects, more effective than conventional starving therapy by only cutting off the energy supply. Furthermore, the generated acidic H2 O2 can oxidize l-Arginine (l-Arg) into NO for enhanced gas therapy. By using hollow mesoporous organosilica nanoparticle (HMON) as a biocompatible/biodegradable nanocarrier for the co-delivery of GOx and l-Arg, a novel glucose-responsive nanomedicine (l-Arg-HMON-GOx) has been for the first time constructed for synergistic cancer starving-like/gas therapy without the need of external excitation, which yields a remarkable H2 O2 -NO cooperative anticancer effect with minimal adverse effect.

  6. 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.

  7. Determination of an acoustic reflection coefficient at the inlet of a model gas turbine combustor for power generation

    NASA Astrophysics Data System (ADS)

    Song, W. J.; Cha, D. J.

    2017-01-01

    A phenomenon that potentially influences the reliability of power generation systems is the presence of thermo-acoustic oscillations in the combustion chamber of a land- based gas turbine. To develop specific measures that prevent the instability, it is essential to predict and/or evaluate the underlying physics of the thermo-acoustics, which requires the acoustic boundary condition at the exit of the burner, that is, at the inlet of the combustor. Here we report a procedure for calculating acoustic reflection coefficients at the burner exit by utilizing two microphone method (TMM) for dynamic pressure signals. The procedure has been verified by comparing its results with reported ones and further successfully employed to determine the acoustic boundary condition of the burner of a partially-premixed model gas turbine combustor.

  8. 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

  9. Final Report - Gas Generation Testing of Uranium Metal in Simulated K Basin Sludge and in Grouted Sludge Waste Forms

    SciTech Connect

    Delegard, Calvin H.; Schmidt, Andrew J.; Sell, Rachel L.; Sinkov, Sergei I.; Bryan, Samuel A.; Gano, Sue; Thornton, Brenda M.

    2004-08-19

    The Waste Isolation Pilot Plant (WIPP) is being considered for the disposal of K Basin sludge as RH-TRU. Because the hydrogen gas concentration in the 55-gallon RH-TRU sealed drums to be transported to WIPP is limited by flammability safety, the number of containers and shipments likely will be driven by the rate of hydrogen generated by the uranium metal-water reaction (U + 2 H{sub 2}O {yields} UO{sub 2} + 2 H{sub 2}) in combination with the hydrogen generated from water and organic radiolysis. Gas generation testing was conducted with uranium metal particles of known surface area, in simulated K West (KW) Basin canister sludge and immobilized in candidate grout solidification matrices. This study evaluated potential for Portland cement and magnesium phosphate grouts to inhibit the reaction of water with uranium metal in the sludge and thereby permit higher sludge loading to the disposed waste form. The best of the grouted waste forms decreased the uranium metal-water reaction by a factor of four.

  10. Dynamic Test Bed Analysis of Gas Energy Balance for a Diesel Exhaust System Fit with a Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Fuc, Pawel; Lijewski, Piotr; Ziolkowski, Andrzej; Dobrzyński, Michal

    2017-02-01

    Analysis of the energy balance for an exhaust system of a diesel engine fit with an automotive thermoelectric generator (ATEG) of our own design has been carried out. A special measurement system and dedicated software were developed to measure the power generated by the modules. The research object was a 1.3-l small diesel engine with power output of 66 kW. The tests were carried out on a dynamic engine test bed that allows reproduction of an actual driving cycle expressed as a function V = f(t), simulating drivetrain (clutch, transmission) operating characteristics, vehicle geometrical parameters, and driver behavior. Measurements of exhaust gas thermodynamic parameters (temperature, pressure, and mass flow) as well as the voltage and current generated by the thermoelectric modules were performed during tests of our own design. Based on the results obtained, the flow of exhaust gas energy in the entire exhaust system was determined along with the ATEG power output. The ideal area of the exhaust system for location of the ATEG was defined to ensure the highest thermal energy recovery efficiency.

  11. Resonant third harmonic generation of KrF laser in Ar gas

    SciTech Connect

    Rakowski, R.; Barna, A.; Suta, T.; Földes, I. B.; Bohus, J.; Szatmári, S.; Mikołajczyk, J.; Bartnik, A.; Fiedorowicz, H.; Verona, C.; Verona Rinati, G.; Margarone, D.; Nowak, T.; and others

    2014-12-15

    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.

  12. Process for Generation of Hydrogen Gas from Various Feedstocks Using Thermophilic Bacteria

    SciTech Connect

    Ooteghem Van, Suellen

    2005-09-13

    A method for producing hydrogen gas is provided comprising selecting a bacteria from the Order Thermotogales, subjecting the bacteria to a feedstock and to a suitable growth environment having an oxygen concentration below the oxygen concentration of water in equilibrium with air; and maintaining the environment at a predetermined pH and at a temperature of at least approximately 45 degrees C. for a time sufficient to allow the bacteria to metabolize the feedstock.

  13. Waste drum gas generation sampling program at Rocky Flats during FY 1989

    SciTech Connect

    Roggenthen, D.K.; Nieweg, R.G.

    1990-10-01

    Rocky Flats Plant transuranic waste drums were sampled for gas composition. Glass, metal, graphite, and solidified inorganic sludge transuranic waste forms were sampled. A vacuum system was used to sample each layer of containment inside a waste drum, including individual waste bags. G values were calculated for the waste drums. G(H{sub 2}) was below 0.6 and G(Total) was below 1.3 for all waste forms discussed in this report. 5 refs., 3 figs., 3 tabs.

  14. Capillary transport of H2 gas generated locally in renal tissue.

    PubMed

    Kirkebø, A; Oien, A H; Aukland, K

    1983-01-01

    Previous measurements by microspheres have shown a higher blood flow in outer cortex and a lower blood flow in inner cortex than found by diffusible tracers. During vasodilation microspheres have indicated a disproportionate increase in deep cortical blood flow, whereas diffusible tracer distributions remained unchanged. These discrepancies could possibly be explained by a variable net inward transport of diffusible tracers in postglomerular vessels, the transport existing in control, but disappearing during vasodilation. To test this hypothesis H2 gas was produced electrolytically for 1 s at a platinum electrode in midcortex and the resulting gas concentration curve measured polarographically at two electrodes placed above and below the source. Analysis of a mathematical model showed that the ratio of the curve maxima at the two electrodes (Cmo/Cmi) would best reveal a radial net transport. Average Cmo/Cmi at 25 positions in 7 clamped dog kidneys was close to unity, but rose to 1.24 at control flow. During acetylcholine infusion Cmo/Cmi rose to 1.68. Local washout rates at the two electrodes increased equally. Calculations indicated a small outwardly directed net transport in control (3 X 10(-4) cm/s), becoming slightly reinforced during vasodilation (5 X 10(-4) cm/s). Thus the control transport direction is opposite to the hypothesis, and the change during vasodilation was estimated to be too small to explain the disparity between diffusible tracer uptake and microsphere distribution in control. H2 concentration maximum was obtained earlier under control flow than in the clamped kidney, indicating an increase in apparent D of the gas in tissue from 3 X 10(-5) cm2/s to 5 X 10(-5) cm2/s, probably due to mixing of H2 gas in the capillary net work.

  15. VUV generation by adiabatically expanded and excited by a DC electrical discharge Argon gas

    SciTech Connect

    Pipergias, K.; Yasemidis, D.; Reppa, E.; Pentaris, D.; Efthimiopoulos, T.; Merlemis, N.; Giannetas, V.

    2010-11-10

    We investigate the emission of Argon (Ar) gas which is adiabatically expanded through a nozzle and excited using a DC electrical discharge. Because of the expansion and the electronic excitation, Ar dimers and clusters are formed, which give radiation in the second (2nd) and in the third (3rd) continua of Ar, centered at about 126 and 254 nm respectively. We particularly focus our study on the 2nd continuum, in order to develop a laser at this wavelength.

  16. Demonstration and Verification of a Turbine Power Generation System Utilizing Renewable Fuel: Landfill Gas

    DTIC Science & Technology

    2013-09-01

    demonstrated at Ft. Benning, the LFG is diluted with ambient air and aspirated directly into the turbine’s compressor with minimal pretreatment (see section...2.1). Some alternative fuel sources (e.g., spent solvent vapors) may require additional gas cleaning, cooling, or pretreatment to avoid excessive...in the air plenum. • Ener-Core reviewed whether flame detectors on the startup system duct burners (E401 warmer and combustor) were required to

  17. Process for generation of hydrogen gas from various feedstocks using thermophilic bacteria

    DOEpatents

    Ooteghem, Suellen Van

    2005-09-13

    A method for producing hydrogen gas is provided comprising selecting a bacteria from the Order Thermotogales, subjecting the bacteria to a feedstock and to a suitable growth environment having an oxygen concentration below the oxygen concentration of water in equilibrium with air; and maintaining the environment at a predetermined pH and at a temperature of at least approximately 45.degree. C. for a time sufficient to allow the bacteria to metabolize the feedstock.

  18. Generation of porphyry copper deposits by gas-brine reaction in volcanic arcs

    NASA Astrophysics Data System (ADS)

    Blundy, J.; Mavrogenes, J.; Tattitch, B.; Sparks, S.; Gilmer, A.

    2015-03-01

    Porphyry copper deposits, that is, copper ore associated with hydrothermal fluids rising from a magma chamber, supply 75% of the world's copper. They are typically associated with intrusions of magma in the crust above subduction zones, indicating a primary role for magmatism in driving mineralization. However, it is not clear that a single, copper-rich magmatic fluid could trigger both copper enrichment and the subsequent precipitation of sulphide ore minerals within a zone of hydrothermally altered rock. Here we draw on observations of modern subduction zone volcanism to propose an alternative process for porphyry copper formation. We suggest that copper enrichment initially involves metalliferous, magmatic hyper-saline liquids, or brines, that exsolve from large, magmatic intrusions assembled in the shallow crust over tens to hundreds of thousands of years. In a subsequent step, sulphide ore precipitation is triggered by the interaction of the accumulated brines with sulphur-rich gases, liberated in short-lived bursts from the underlying mafic magmas. We use high-temperature and high-pressure laboratory experiments to simulate such gas-brine interactions. The experiments yield copper-iron sulphide minerals and hydrogen chloride gas at magmatic temperatures of 700-800 °C, with textural and chemical characteristics that resemble those in porphyry copper deposits. We therefore conclude that porphyry copper ore forms in a two-stage process of brine enrichment followed by gas-induced precipitation.

  19. Combined solid oxide fuel cell and gas turbine systems for efficient power and heat generation

    NASA Astrophysics Data System (ADS)

    Palsson, Jens; Selimovic, Azra; Sjunnesson, Lars

    The Department of Heat and Power Engineering at Lund University in Sweden has been conducting theoretical studies of combined SOFC and gas turbine (SOFC/GT) cycles. The overall goal is an unbiased evaluation of performance prospects and operational behaviour of such systems. The project is part of a Swedish national program on high-temperature fuel cells. Results of continuous studies started earlier by authors are presented. Recent developments in modelling techniques has resulted in a more accurate fuel cell model giving an advantage over previous system studies based on simplified SOFC models. The fuel cell model has been improved by detailed representation of resistive cell losses, reaction kinetics for the reforming reaction and heat conduction through the solid part of the cell. This SOFC model has further been confirmed against the literature and integrated into simulation software, Aspen Plus™. Recent calculations have focused on a system with external pre-reforming and anode gas recirculation for the internal supply of steam. A reference system, sized at 500 kW, has also been analyzed in variants with gas turbine reheat and air compression intercooling. In addition, knowledge of stack and system behaviour has been gained from sensitivity studies. It is shown that the pressure ratio has a large impact on performance and that electrical efficiencies of more than 65% are possible at low pressure ratios.

  20. US Greenhouse Gas (GHG) Emissions and Avoided Emissions and Generation Tool Training (AVERT) (2015 EIC)

    EPA Pesticide Factsheets

    AVERT captures the actual historical behavior of electricity generating units' (EGUs’) operation on an hourly basis to predict how EGUs will operate with additional EE/RE delivered to the electricity grid.

  1. 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 ...

  2. On-Site Renewable Energy Generation: A Guide to Developing and Implementing Greenhouse Gas Reduction Programs

    EPA Pesticide Factsheets

    This guide describes a variety of approaches that local governments can use to advance climate and energy goals by meeting some or all of their electricity needs through on-site renewable energy generation.

  3. Large-scale generation and screening of hypothetical metal-organic frameworks for applications in gas storage and separations.

    PubMed

    Wilmer, Christopher E; Snurr, Randall Q

    2014-01-01

    Metal-organic frameworks (MOFs) are porous crystals that are synthesized in a building-block approach that greatly facilitates rational design. MOFs are promising materials for gas storage and separation applications, but they are also intriguing for their potential use as catalysts, electrodes, and drug delivery vehicles. For these reasons, MOFs have spurred a renewed interest in the concept of "crystal engineering," where the crystal structure of a material is designed to meet application-specific criteria. This chapter reviews recent work in the computational design of MOFs, with an emphasis on high-throughput methods that generate and screen many thousands of candidates automatically.

  4. Plant for preparing and hydrogenating fossil fuels to prepare products low in sulfur content, and employment of these products for combined generation of the electric current and gas

    SciTech Connect

    Schuster, E.; Knizia, K.

    1986-07-01

    A plant is described for producing solid and gaseous desulfurizing fossil fuels for use in a gas turbine power plant and a steam power plant for electric power generation. The plant consists of operatively interconnected components including sequentially in combination: crusher means for crushing the fuel to a particle size not to exceed 0.1 mm., a vapor separator, means for supplying hot, substantially inert, flue gas to the crusher means to convey the crushed fuel to the separator with simultaneous evaporation of moisture therefrom, a preoxidation station, means to convey the fuel to the preoxidation station, means to convey the fuel to the preoxidation station, means to supply heated air to the preoxidation station to oxidize the fuel, a separator for separating the air from the oxidized fuel, a reaction chamber station and means to supply the chamber with the pre-oxidized fuel and in which chamber the gas content of the fuel is adjusted, means for supplying steam to the reaction chamber station to hydrolyze the fuel, a separator station past the reaction chamber station to separate the oxidized fuel from gas, an additional gas driven conveyor and distributor means for distributing the solid product from the reaction chamber station to the steam generator plant, means for extensively desulfurized gas leaving the separator from the reaction chamber station, distributor means for distributing the desulfurized gas to the gas turbine power plant and at least a portion of the gas to the steam generator plant.

  5. Effect of a transverse magnetic field on the generation of electron beams in the gas-filled diode

    NASA Astrophysics Data System (ADS)

    Baksht, E. H.; Burachenko, A. G.; Erofeev, M. V.; Kostyrya, I. D.; Lomaev, M. I.; Rybka, D. V.; Tarasenko, V. F.

    2008-06-01

    The effect of a transverse magnetic field (0.080 and 0.016 T) on generation of an electron beam in the gas-filled diode is experimentally investigated. It is shown that, at voltage U = 25 kV across the diode and a low helium pressure (45 Torr), the transverse magnetic field influences the beam current amplitude behind a foil and its distribution over the foil cross section. At elevated pressures and under the conditions of ultrashort avalanche electron beam formation in helium, nitrogen, and air, the transverse magnetic field (0.080 and 0.016 T) has a minor effect on the amplitude and duration of the beam behind the foil. It is established that, when the voltage of the pulse generator reaches several hundreds of kilovolts, some runaway electrons (including the electrons from the discharge plasma near the cathode) are incident on the side walls of the diode.

  6. Exergy destruction analysis of a vortices generator in a gas liquid finned tube heat exchanger: an experimental study

    NASA Astrophysics Data System (ADS)

    Ghazikhani, M.; Khazaee, I.; Monazzam, S. M. S.; Takdehghan, H.

    2016-11-01

    In the present work, the effect of using different shapes of vortices generator (VG) on a gas liquid finned heat exchanger is investigated experimentally with irreversibility analysis. In this project the ambient air with mass flow rates of 0.047-0.072 kg/s is forced across the finned tube heat exchanger. Hot water with constant flow rate of 240 L/h is circulated inside heat exchanger tubes with inlet temperature range of 45-73 °C. The tests are carried out on the flat finned heat exchanger and then repeated on the VG finned heat exchanger. The results show that using the vortex generator can decrease the ratio of air side irreversibility to heat transfer (ASIHR) of the heat exchanger. Also the results show that the IASIHR is >1.05 for all air mass flow rates, which means that ASIHR for the initial heat exchanger is higher than 5 % greater than that of improved heat exchanger.

  7. Evidence for bacterially generated hydrocarbon gas in Canadian shield and Fennoscandian shield rocks

    SciTech Connect

    Lollar, B.S.; Frape, S.K. ); Fritz, P. ); Macko, S.A. ); Welhan, J.A. ); Blomqvist, R.; Lahermo, P.W. )

    1993-12-01

    Hydrocarbon-rich gases found in crystalline rocks on the Canadian and Fennoscandian shields are isotopically and compositionally similar, suggesting that such gases are a characteristic feature of Precambrian Shields rocks. Gases occur in association with saline groundwaters and brines in pressurized [open quotes]pockets[close quotes] formed by sealed fracture systems within the host rocks. When released by drilling activities, gas pressures as high as 5000 kPa have been recorded. Typical gas flow rates for individual boreholes range from 0.25 L/min to 4 L/min. The highest concentrations of CH[sub 4] are found in the deepest levels of the boreholes associated with Ca-Na-Cl (and Na-Ca-Cl) brines. N[sub 2] is the second major component of the gases and with CH[sub 4] accounts for up to 80 to >90 vol%. Higher hydrocarbon (C[sup +][sub 2]) concentrations range from <1 to 10 vol%, with Cl/(C2 + C3) ratios from 10-1000. Isotopically the gases show a wide range of values overall ([delta][sup 13]C = -57.5 to -41.1%; [delta]D = -245 to -470%) but a relatively tight cluster of values within each sampling locality. The Enonkoski Mine methanes are unique with [delta][sup 13]C values between -65.4 and -67.3% and [delta]D values between -297 and -347%. The shield gases are not readily reconcilable with conventional theories of methanogenesis. The range of C1/(C2 + C3) ratios for the shield gases is too low to be consistent with an entirely bacterial origin. In addition, [delta]D[sub CH4] values are in general too depleted in the heavy isotope to be produced by thermogenic methanogenesis or by secondary alteration processes such as bacterial oxidation or migration. However, isotopic and compositional evidence indicates that bacterially derived gas can account for a significant component of the gas at all shield sites.

  8. Potential benefits of a ceramic thermal barrier coating on large power generation gas turbine

    NASA Technical Reports Server (NTRS)

    Clark, J. S.; Nainiger, J. J.

    1977-01-01

    Thermal barrier coating design option offers benefit in terms of reduced electricity costs when used in utility gas turbines. Options considered include: increased firing temperature, increased component life, reduced cooling air requirements, and increased corrosion resistance (resulting in increased tolerance for dirty fuels). Performance and cost data were obtained. Simple, recuperated and combined cycle applications were considered, and distillate and residual fuels were assumed. The results indicate that thermal barrier coatings could produce large electricity cost savings if these coatings permit turbine operation with residual fuels at distillate-rated firing temperatures. The results also show that increased turbine inlet temperature can result in substantial savings in fuel and capital costs.

  9. Steady Secondary Flows Generated by Periodic Compression and Expansion of an Ideal Gas in a Pulse Tube

    NASA Technical Reports Server (NTRS)

    Lee, Jeffrey M.

    1999-01-01

    This study establishes a consistent set of differential equations for use in describing the steady secondary flows generated by periodic compression and expansion of an ideal gas in pulse tubes. Also considered is heat transfer between the gas and the tube wall of finite thickness. A small-amplitude series expansion solution in the inverse Strouhal number is proposed for the two-dimensional axisymmetric mass, momentum and energy equations. The anelastic approach applies when shock and acoustic energies are small compared with the energy needed to compress and expand the gas. An analytic solution to the ordered series is obtained in the strong temperature limit where the zeroth-order temperature is constant. The solution shows steady velocities increase linearly for small Valensi number and can be of order I for large Valensi number. A conversion of steady work flow to heat flow occurs whenever temperature, velocity or phase angle gradients are present. Steady enthalpy flow is reduced by heat transfer and is scaled by the Prandtl times Valensi numbers. Particle velocities from a smoke-wire experiment were compared with predictions for the basic and orifice pulse tube configurations. The theory accurately predicted the observed steady streaming.

  10. Characterization of airborne particles generated from metal active gas welding process.

    PubMed

    Guerreiro, C; Gomes, J F; Carvalho, P; Santos, T J G; Miranda, R M; Albuquerque, P

    2014-05-01

    This study is focused on the characterization of particles emitted in the metal active gas welding of carbon steel using mixture of Ar + CO2, and intends to analyze which are the main process parameters that influence the emission itself. It was found that the amount of emitted particles (measured by particle number and alveolar deposited surface area) are clearly dependent on the distance to the welding front and also on the main welding parameters, namely the current intensity and heat input in the welding process. The emission of airborne fine particles seems to increase with the current intensity as fume-formation rate does. When comparing the tested gas mixtures, higher emissions are observed for more oxidant mixtures, that is, mixtures with higher CO2 content, which result in higher arc stability. These mixtures originate higher concentrations of fine particles (as measured by number of particles by cm(3) of air) and higher values of alveolar deposited surface area of particles, thus resulting in a more severe worker's exposure.

  11. 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.

  12. A Safe and Easy Classroom Demonstration of the Generation of Acetylene Gas.

    ERIC Educational Resources Information Center

    Cox, Marilyn Blagg; Krause, Paul

    1994-01-01

    In this demonstration of the generation and combustion of acetylene, calcium carbide and water are allowed to react in a latex examination glove. Two student volunteers perform the demonstration with instructor guidance. This safe, popular demonstration, originally intended to illustrate the alkyne family of compounds, can be used with a variety…

  13. Second harmonic generation of spectrally broadened femtosecond ytterbium laser radiation in a gas-filled capillary

    SciTech Connect

    Didenko, N V; Konyashchenko, Aleksandr V; Kostryukov, P V; Losev, Leonid L; Tenyakov, S Yu

    2011-09-30

    A 300-fs radiation pulse of an ytterbium laser with a wavelength of 1030 nm and energy of 150 {mu}J were converted to a 15-fs pulse with a wavelength of 515 nm by broadening the emission spectrum in a capillary filled with xenon and by generating the second harmonic in a KDP crystal. The energy efficiency of the conversion was 30 %.

  14. Soluble Axl is generated by ADAM10-dependent cleavage and associates with Gas6 in mouse serum.

    PubMed

    Budagian, Vadim; Bulanova, Elena; Orinska, Zane; Duitman, Erwin; Brandt, Katja; Ludwig, Andreas; Hartmann, Dieter; Lemke, Greg; Saftig, Paul; Bulfone-Paus, Silvia

    2005-11-01

    Axl receptor tyrosine kinase exists as a transmembrane protein and as a soluble molecule. We show that constitutive and phorbol 12-myristate 13-acetate-induced generation of soluble Axl (sAxl) involves the activity of disintegrin-like metalloproteinase 10 (ADAM10). Spontaneous and inducible Axl cleavage was inhibited by the broad-spectrum metalloproteinase inhibitor GM6001 and by hydroxamate GW280264X, which is capable of blocking ADAM10 and ADAM17. Furthermore, murine fibroblasts deficient in ADAM10 expression exhibited a significant reduction in constitutive and inducible Axl shedding, whereas reconstitution of ADAM10 restored sAxl production, suggesting that ADAM10-mediated proteolysis constitutes a major mechanism for sAxl generation in mice. Partially overlapping 14-amino-acid stretch deletions in the membrane-proximal region of Axl dramatically affected sAxl generation, indicating that these regions are involved in regulating the access of the protease to the cleavage site. Importantly, relatively high circulating levels of sAxl are present in mouse sera in a heterocomplex with Axl ligand Gas6. Conversely, two other family members, Tyro3 and Mer, were not detected in mouse sera and conditioned medium. sAxl is constitutively released by murine primary cells such as dendritic and transformed cell lines. Upon immobilization, sAxl promoted cell migration and induced the phosphorylation of Axl and phosphatidylinositol 3-kinase. Thus, ADAM10-mediated generation of sAxl might play an important role in diverse biological processes.

  15. Soluble Axl Is Generated by ADAM10-Dependent Cleavage and Associates with Gas6 in Mouse Serum†

    PubMed Central

    Budagian, Vadim; Bulanova, Elena; Orinska, Zane; Duitman, Erwin; Brandt, Katja; Ludwig, Andreas; Hartmann, Dieter; Lemke, Greg; Saftig, Paul; Bulfone-Paus, Silvia

    2005-01-01

    Axl receptor tyrosine kinase exists as a transmembrane protein and as a soluble molecule. We show that constitutive and phorbol 12-myristate 13-acetate-induced generation of soluble Axl (sAxl) involves the activity of disintegrin-like metalloproteinase 10 (ADAM10). Spontaneous and inducible Axl cleavage was inhibited by the broad-spectrum metalloproteinase inhibitor GM6001 and by hydroxamate GW280264X, which is capable of blocking ADAM10 and ADAM17. Furthermore, murine fibroblasts deficient in ADAM10 expression exhibited a significant reduction in constitutive and inducible Axl shedding, whereas reconstitution of ADAM10 restored sAxl production, suggesting that ADAM10-mediated proteolysis constitutes a major mechanism for sAxl generation in mice. Partially overlapping 14-amino-acid stretch deletions in the membrane-proximal region of Axl dramatically affected sAxl generation, indicating that these regions are involved in regulating the access of the protease to the cleavage site. Importantly, relatively high circulating levels of sAxl are present in mouse sera in a heterocomplex with Axl ligand Gas6. Conversely, two other family members, Tyro3 and Mer, were not detected in mouse sera and conditioned medium. sAxl is constitutively released by murine primary cells such as dendritic and transformed cell lines. Upon immobilization, sAxl promoted cell migration and induced the phosphorylation of Axl and phosphatidylinositol 3-kinase. Thus, ADAM10-mediated generation of sAxl might play an important role in diverse biological processes. PMID:16227584

  16. PM2.5 and ultrafine particulate matter emissions from natural gas-fired turbine for power generation

    NASA Astrophysics Data System (ADS)

    Brewer, Eli; Li, Yang; Finken, Bob; Quartucy, Greg; Muzio, Lawrence; Baez, Al; Garibay, Mike; Jung, Heejung S.

    2016-04-01

    The generation of electricity from natural gas-fired turbines has increased more than 200% since 2003. In 2007 the South Coast Air Quality Management District (SCAQMD) funded a project to identify control strategies and technologies for PM2.5 and ultrafine emissions from natural gas-fired turbine power plants and test at pilot scale advanced PM2.5 technologies to reduce emissions from these gas turbine-based power plants. This prompted a study of the exhaust from new facilities to better understand air pollution in California. To characterize the emissions from new natural gas turbines, a series of tests were performed on a GE LMS100 gas turbine located at the Walnut Creek Energy Park in August 2013. These tests included particulate matter less than 2.5 μm in diameter (PM2.5) and wet chemical tests for SO2/SO3 and NH3, as well as ultrafine (less than 100 nm in diameter) particulate matter measurements. After turbine exhaust was diluted sevenfold with filtered air, particle concentrations in the 10-300 nm size range were approximately two orders of magnitude higher than those in the ambient air and those in the 2-3 nm size range were up to four orders of magnitude higher. This study also found that ammonia emissions were higher than expected, but in compliance with permit conditions. This was possibly due to an ammonia imbalance entering the catalyst, some flue gas bypassing the catalyst, or not enough catalyst volume. SO3 accounted for an average of 23% of the total sulfur oxides emissions measured. While some of the SO3 is formed in the combustion process, it is likely that the majority formed as the SO2 in the combustion products passed across the oxidizing CO catalyst and SCR catalyst. The 100 MW turbine sampled in this study emitted particle loadings of 3.63E-04 lb/MMBtu based on Methods 5.1/201A and 1.07E-04 lb/MMBtu based on SMPS method, which are similar to those previously measured from turbines in the SCAQMD area (FERCo et al., 2014), however, the turbine

  17. 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.

  18. Evaluation of distributed gas cooling of pressurized PAFC for utility power generation

    NASA Technical Reports Server (NTRS)

    Farooque, M.; Maru, H.; Skok, A.

    1981-01-01

    Two short stacks were pressure tested at 446 kPa (4.4 atm.) and the pressure gains were more than the theoretically predicted gains. Temperature profiles were observed to be independent of operating pressure. The pressure drop was found to be inversely proportional to operating pressure as expected. Continuous pressurized operation of a stack for 1000 hours verified the compatability of the fuel cell component design. A simple pressurization procedure was also developed. Six separate designs, covering two gas cooling schemes (DIGAS and separated) and two cooling channel geometries (straight through and treed), were analysed on the net voltage output basis. Separated cooling with 5 cells per cooler was recognized to be the best among the designs considered.

  19. New high-nitrogen energetic materials for gas generators in space ordnance

    SciTech Connect

    Campbell, M.S.; Lee, Kien-Yin; Hiskey, M.A.

    1995-08-01

    High-nitrogen nitroheterocyclic energetic compounds are used as explosives, propellants, and gas generants when safe, thermally stable, cool-burning energetic materials are desired. A series of compounds are compared for sensitivity properties and calculated burn performance. Thermodynamic equilibrium calculations by NASA/Lewis rocket propellant and Blake gun propellant codes gave flame temperatures, average molecular weight, and identity of the equilibrium burn products for ambient, rocket, and gun pressure environments. These compounds were subjected to calculations both as monopropellants and as 50/50 weight ratio mixtures with ammonium nitrate (AN). Special attention was paid to calculated toxic products such as carbon monoxide and hydrogen cyanide, and how these were affected by the addition of an oxidizer AN. Several compounds were noted for further calculations of a formulation ad experimental evaluation.

  20. Suprathermal Electrons Generated by the Two-Plasmon-Decay Instability in Gas-Filled Hohlraums

    SciTech Connect

    Regan, S P; Seka, W; Stoeckl, C; Glebov, V Y; Sangster, T C; Meyerhofer, D D; McCrory, R L; Meezan, N B; Suter, L J; Glenzer, S H; Strozzi, D J; Meeker, D; Williams, E A; Jones, O S; Callahan, D A; Rosen, M D; Landen, O L; Sorce, C; MacGowan, B J; Kruer, W L

    2008-06-03

    For the first time a burst of suprathermal electrons is observed from the exploding laser-entrance-hole window of gas-filled hohlraums driven with 13.5 kJ of 351-nm laser light. The two-plasmon-decay instability appears to produce up to 20 J of hot electrons with T{sub hot} {approx} 75 keV at early times and has a sharp laser-intensity threshold between 0.3 and 0.5 x 10{sup 15} W/cm{sup 2}. The observed threshold can be exploited to mitigate preheat by window hot electrons in ignition hohlraums for the National Ignition Facility and achieve high-density, high-pressure conditions in indirect drive implosions.

  1. Aerobic biodegradation of sludge with high hydrocarbon content generated by a Mexican natural gas processing facility.

    PubMed

    Roldán-Carrillo, T; Castorena-Cortés, G; Zapata-Peñasco, I; Reyes-Avila, J; Olguín-Lora, P

    2012-03-01

    The biodegradation of oil sludge from Mexican sour gas and petrochemical facilities contaminated with a high content of hydrocarbons, 334.7 ± 7.0 g kg(-1) dry matter (dm), was evaluated. Studies in microcosm systems were carried out in order to determine the capacity of the native microbiota in the sludge to reduce hydrocarbon levels under aerobic conditions. Different carbon/nitrogen/phosphorous (C/N/P) nutrient ratios were tested. The systems were incubated at 30 °C and shaken at 100 rpm. Hydrocarbon removals from 32 to 51% were achieved in the assays after 30 days of incubation. The best assay had C/N/P ratio of 100/1.74/0.5. The results of the Microtox(®) and Ames tests indicated that the original sludge was highly toxic and mutagenic, whereas the best assay gave a final product that did not show toxicity or mutagenicity.

  2. Mechanisms of gas generation from simulated SY tank farm wastes: FY 1995 progress report

    SciTech Connect

    Barefield, E.K.; Boatright, D.; Deshpande, A.; Doctorovich, F.; Liotta, C.L.; Neumann, H.M.; Seymore, S.

    1996-07-01

    The objective of this work is to develop a better understanding of the mechanism of formation of flammable gases in the thermal decomposition of metal complexants such as HEDTA and sodium glycolate in simulated SY tank farm waste mixtures. This report summarizes the results of work done at the Georgia Institute of Technology in fiscal year 1995. Topics discussed are (1) long-term studies of the decomposition of HEDTA in simulated waste mixtures under an argon atmosphere at 90 and 120{degrees}C, including time profiles for disappearance of HEDTA and appearance of products and the quantitative analysis of the kinetic behavior; (2) considerations of hydroxylamine as an intermediate in the production of nitrogen containing gases by HEDTA decomposition; (3) some thoughts on the revision of the global mechanism for thermal decomposition of HEDTA under argon; (4) preliminary long-term studies of the decomposition of HEDTA in simulated waste under an oxygen atmosphere at 120{degrees}C; (5) estimation of the amount of NH{sub 3} in the gas phase above HEDTA reaction mixtures; and (6) further, examination of the interaction of aluminum with nitrite ion using {sup 27}Al NMR spectroscopy. Section 2 of this report describes the work conducted over the last three years at GIT. Section 3 contains a discussion of the kinetic behavior of HEDTA under argon; Section 4 discusses the role of hydroxylamine. Thermal decomposition of HEDTA to ED3A is the subject of Section 5, and decomposition of HEDTA in simulated waste mixtures under oxygen is covered in Section 6. In Section 7 we estimate ammonia in the gas phase; the role of aluminum is discussed in Section 8.

  3. Crackling sound generation during the formation of liquid bridges: A lattice gas model

    NASA Astrophysics Data System (ADS)

    Almeida, Alexandre B.; Buldyrev, Sergey V.; Alencar, Adriano M.

    2013-08-01

    Due to abnormal mechanical instabilities, liquid bridges may form in the small airways blocking airflow. Liquid bridge ruptures during inhalation are the major cause of the crackling adventitious lung sound, which can be heard using a simple stethoscope. Recently, Vyshedskiy and colleagues (2009) [1] described and characterized a crackle sound originated during expiration. However, the mechanism and origin of the expiratory crackle are still controversial. Thus, in this paper, we propose a mechanism for expiratory crackles. We hypothesize that the expiratory crackle sound is a result of the energy released in the form of acoustic waves during the formation of the liquid bridge. The magnitude of the energy released is proportional to the difference in free energy prior and after the bridge formation. We use a lattice gas model to describe the liquid bridge formation between two parallel planes. Specifically, we determine the surface free energy and the conditions of the liquid bridge formation between two parallel planes separated by a distance 2h by a liquid droplet of volume Ω and contact angle Θ, using both Monte Carlo simulation of a lattice gas model and variational calculus based on minimization of the surface area with the volume and the contact angle constrained. We numerically and analytically determine the phase diagram of the system as a function of the dimensionless parameter hΩ and Θ. We can distinguish two different phases: one droplet and one liquid bridge. We observe a hysteresis curve for the energy changes between these two states, and a finite size effect in the bridge formation. We compute the release of free energy during the formation of the liquid bridge and discuss the results in terms of system size. We also calculate the force exerted from liquid bridge on the planes by studying the dependence of the free energy on the separation between the planes 2h. The simulation results are in agreement with the analytical solution.

  4. Optimization of an electromagnetic generator for strong shocks in low pressure gas

    NASA Astrophysics Data System (ADS)

    Larour, Jean; Singh, Raj Laxmi; Stehlé, Chantal; Ciardi, Andrea; Chaulagain, Uddhab; Suzuki-Vidal, Francisco

    2015-12-01

    In this paper, we present the design and optimization of an electromagnetic generator, able to produce strong shocks in noble gases, relevant to astrophysical conditions. It is a powerful accelerating device which ejects a quasi-planar plasma sheath out of a set of coaxial conical electrodes where a pulsed 100-kA current is passing. A simple model is used to optimize the operation parameters. Preliminary experiments show that the generator is capable of launching supersonic shocks in Argon, in the form of a thin plasma layer with the speed of ∼1-30 km/s. A three-dimension MHD simulation gives a description consistent with the model and with the observations.

  5. Optimizing Gas Generator Efficiency in a Forward Operating Base Using an Energy Management System

    DTIC Science & Technology

    2013-06-01

    System IGBT IPM Insulated Gate Bipolar Transistor Integrated Power Module LCD Liquid Crystal Display LED Light-emitting Diode PC Personal Computer...control signals to the functional components on the PCB. These components include the insulated gate bipolar transistor integrated power module (IGBT IPM...PCB Printed Circuit Board RC Resistor-capacitor RMS Root-mean-square SoC State of Charge TQG Tactical Quiet Generator TTL Transistor - transistor

  6. Apparatus and methods of reheating gas turbine cooling steam and high pressure steam turbine exhaust in a combined cycle power generating system

    DOEpatents

    Tomlinson, Leroy Omar; Smith, Raub Warfield

    2002-01-01

    In a combined cycle system having a multi-pressure heat recovery steam generator, a gas turbine and steam turbine, steam for cooling gas turbine components is supplied from the intermediate pressure section of the heat recovery steam generator supplemented by a portion of the steam exhausting from the HP section of the steam turbine, steam from the gas turbine cooling cycle and the exhaust from the HP section of the steam turbine are combined for flow through a reheat section of the HRSG. The reheated steam is supplied to the IP section inlet of the steam turbine. Thus, where gas turbine cooling steam temperature is lower than optimum, a net improvement in performance is achieved by flowing the cooling steam exhausting from the gas turbine and the exhaust steam from the high pressure section of the steam turbine in series through the reheater of the HRSG for applying steam at optimum temperature to the IP section of the steam turbine.

  7. Dilution and permeation standards for the generation of NO, NO2 and SO2 calibration gas mixtures

    NASA Astrophysics Data System (ADS)

    Haerri, H.-P.; Macé, T.; Waldén, J.; Pascale, C.; Niederhauser, B.; Wirtz, K.; Stovcik, V.; Sutour, C.; Couette, J.; Waldén, T.

    2017-03-01

    The evaluation results of the metrological performance of a dilution and a permeation standard for generating SI-traceable calibration gas mixtures of NO, SO2 and NO2 for ambient air measurements are presented. The composition of the in situ produced reference gas mixtures is calculated from the instantaneous values of the input quantities of the generating standards. In a measurement comparison, the calibration and measurement capabilities of five laboratories were evaluated for the three analytes at limiting amount of substance fractions in ambient air between 20 and 150 nmol mol-1. For the upper generated reference values the target relative uncertainties of  ⩽2% (for NO and SO2) and  ⩽3% (for NO2) for evaluating the laboratory results were fulfilled in 12 out of 13 cases. For the analytical results seven out of nine laboratories met the criteria for the upper values for NO and NO2, for SO2 it was one out of four. From the negative degrees of equivalence of all NO2 comparison results it was supposed that the permeation rate of NO2 through the FEP polymer membrane of the permeator was different in air and N2. Subsequent precision permeation measurements with various carrier gases revealed that the permeation rate of NO2 was  ≈0.8% lower in synthetic air compared to N2. With the corrected NO2 reference values for air the degrees of equivalence of the laboratory results were improved and closer to be symmetrically distributed.

  8. Coupled multiphase flow and closure analysis of repository response to waste-generated gas at the Waste Isolation Pilot Plant (WIPP)

    SciTech Connect

    Freeze, G.A.; Larson, K.W.; Davies, P.B.

    1995-10-01

    A long-term assessment of the Waste Isolation Pilot Plant (WIPP) repository performance must consider the impact of gas generation resulting from the corrosion and microbial degradation of the emplaced waste. A multiphase fluid flow code, TOUGH2/EOS8, was adapted to model the processes of gas generation, disposal room creep closure, and multiphase (brine and gas) fluid flow, as well as the coupling between the three processes. System response to gas generation was simulated with a single, isolated disposal room surrounded by homogeneous halite containing two anhydrite interbeds, one above and one below the room. The interbeds were assumed to have flow connections to the room through high-permeability, excavation-induced fractures. System behavior was evaluated by tracking four performance measures: (1) peak room pressure; (2) maximum brine volume in the room; (3) total mass of gas expelled from the room; and (4) the maximum gas migration distance in an interbed. Baseline simulations used current best estimates of system parameters, selected through an evaluation of available data, to predict system response to gas generation under best-estimate conditions. Sensitivity simulations quantified the effects of parameter uncertainty by evaluating the change in the performance measures in response to parameter variations. In the sensitivity simulations, a single parameter value was varied to its minimum and maximum values, representative of the extreme expected values, with all other parameters held at best-estimate values. Sensitivity simulations identified the following parameters as important to gas expulsion and migration away from a disposal room: interbed porosity; interbed permeability; gas-generation potential; halite permeability; and interbed threshold pressure. Simulations also showed that the inclusion of interbed fracturing and a disturbed rock zone had a significant impact on system performance.

  9. Generation of porphyry copper deposits by gas-brine reaction in volcanic arcs

    NASA Astrophysics Data System (ADS)

    Blundy, Jon; Mavrogenes, John; Tattitch, Brian; Sparks, Steve; Gilmer, Amy

    2014-05-01

    Porphyry copper deposits (PCDs) are characterised by a close spatial and temporal association with small, hypabyssal intrusions of silicic magmas in volcanic arcs. PCD formation requires elevated chlorine and water to concentrate copper in magmatic hypersaline liquids (or brines), and elevated sulphur to precipitate copper-rich sulphides. These twin requirements are hard to reconcile with experimental and petrological evidence that voluminous chlorine-rich, hydrous silicic magmas, of the variety favourable to copper enrichment, lack sufficient sulphur to precipitate directly the requisite quantities of sulphides. These features are, however, consistent with observations of active volcanic arcs whereby PCDs can be viewed as roots of dome volcanoes above shallow reservoirs where silicic magmas accumulate over long time spans. During protracted periods of dormancy metal-enriched dense brines accumulate in and above the silicic reservoir through slow, low-pressure degassing. Meanwhile cogenetic volatile-rich mafic magmas and their exsolved, sulphur and CO2-rich fluids accumulate in deeper reservoirs. Periodic destabilisation of these reservoirs leads to short-lived bursts of volcanism liberating sulphurous gases, which react with the shallow-stored brines to form copper-rich sulphides and acidic vapours. We test this hypothesis with a novel set of 'porphyry in a capsule' experiments designed to simulate low-pressure (1-2 kbar) interaction of basalt-derived, sulphur-rich gases with brine-saturated, copper-bearing, but sulphur-free, granite. Experiments were run at 720-850 ° C in cold-seal apparatus with basaltic andesite, loaded with H2O and S, situated below dacite, loaded with H2O, Cl and Cu. At run conditions both compositions are substantially degassed and crystallized. S-rich gas from the basaltic andesite ascends to react with Cu-rich brines exsolved from the dacite, Our experiments reveal the direct precipitation of copper-sulphide minerals, in vugs and veins

  10. ZTEK`s ultra-high efficiency fuel cell/gas turbine system for distributed generation

    SciTech Connect

    Hsu, M.; Nathanson, D.; Bradshaw, D.T.

    1996-12-31

    Ztek`s Planar Solid Oxide Fuel Cell (SOFC) system has exceptional potential for utility electric power generation because of: simplicity of components construction, capability for low cost manufacturing, efficient recovery of very high quality by-product heat (up to 1000{degrees}C), and system integration simplicity. Utility applications of the Solid Oxide Fuel Cell are varied and include distributed generation units (sub-MW to 30MW capacity), repowering existing power plants (i.e. 30MW to 100MW), and multi-megawatt central power plants. A TVA/EPRI collaboration program involved functional testing of the advanced solid oxide fuel cell stacks and design scale-up for distributed power generation applications. The emphasis is on the engineering design of the utility modules which will be the building blocks for up to megawatt scale power plants. The program has two distinctive subprograms: Verification test on a 1 kW stack and 25kW module for utility demonstration. A 1 kW Planar SOFC stack was successfully operated for 15,000 hours as of December, 1995. Ztek began work on a 25kW SOFC Power System for TVA, which plans to install the 25kW SOFC at a host site for demonstration in 1997. The 25kW module is Ztek`s intended building block for the commercial use of the Planar SOFC. Systems of up to megawatt capacity can be obtained by packaging the modules in 2-dimensional or 3-dimensional arrays.

  11. Gap-gate field effect gas sensing device for chemical image generation

    NASA Astrophysics Data System (ADS)

    Filippini, D.; Lundström, I.; Uchida, H.

    2004-04-01

    A field effect chemically sensitive device, specially suited for the generation of scanning light pulse technique chemical images, is demonstrated. The present approach provides a complete separation between the required electrical biasing and chemical sensing functions inherently coupled in all previous systems. The concept is demonstrated by sensing hydrogen with insensitive biasing electrodes, composing a so-called gap gate, combined with discontinuous palladium clusters usually unsuitable for sensing in conventional arrangements. A simple one-dimensional model is used to explain the observed behavior.

  12. State-level Greenhouse Gas Emission Factors for Electricity Generation, Updated

    EIA Publications

    2001-01-01

    To assist reporters in estimating emissions and emission reductions, The Energy Information Administration (EIA) has made available in the instructions to Forms EIA-1605 and EIA-1605EZ emission coefficients for most commonly used fossil fuels and electricity. These coefficients were based on 1992 emissions and generation data. In 1999, updated coefficients were prepared based on the most recent data (1998) then available; however, the updated coefficients were not included in the instructions for the 1999 data year. This year, they have been updated again, but based on three years worth of data (1997, 1998, and 1999) rather than a single year.

  13. Study of hydrogen generation plant coupled to high temperature gas cooled reactor

    NASA Astrophysics Data System (ADS)

    Brown, Nicholas Robert

    Hydrogen generation using a high temperature nuclear reactor as a thermal driving vector is a promising future option for energy carrier production. In this scheme, the heat from the nuclear reactor drives an endothermic water-splitting plant, via coupling, through an intermediate heat exchanger. While both high temperature nuclear reactors and hydrogen generation plants have high individual degrees of development, study of the coupled plant is lacking. Particularly absent are considerations of the transient behavior of the coupled plant, as well as studies of the safety of the overall plant. The aim of this document is to contribute knowledge to the effort of nuclear hydrogen generation. In particular, this study regards identification of safety issues in the coupled plant and the transient modeling of some leading candidates for implementation in the Nuclear Hydrogen Initiative (NHI). The Sulfur Iodine (SI) and Hybrid Sulfur (HyS) cycles are considered as candidate hydrogen generation schemes. Several thermodynamically derived chemical reaction chamber models are coupled to a well-known reference design of a high temperature nuclear reactor. These chemical reaction chamber models have several dimensions of validation, including detailed steady state flowsheets, integrated loop test data, and bench scale chemical kinetics. Eight unique case studies are performed based on a thorough literature review of possible events. The case studies are: (1) feed flow failure from one section of the chemical plant to another, (2) product flow failure (recycle) within the chemical plant, (3) rupture or explosion within the chemical plant, (4) nuclear reactor helium inlet overcooling due to a process holding tank failure, (5) helium inlet overcooling as an anticipated transient without SCRAM, (6) total failure of the chemical plant, (7) parametric study of the temperature in an individual reaction chamber, and (8) control rod insertion in the nuclear reactor. Various parametric

  14. Updated greenhouse gas and criteria air pollutant emission factors and their probability distribution functions for electricity generating units

    SciTech Connect

    Cai, H.; Wang, M.; Elgowainy, A.; Han, J.

    2012-07-06

    Greenhouse gas (CO{sub 2}, CH{sub 4} and N{sub 2}O, hereinafter GHG) and criteria air pollutant (CO, NO{sub x}, VOC, PM{sub 10}, PM{sub 2.5} and SO{sub x}, hereinafter CAP) emission factors for various types of power plants burning various fuels with different technologies are important upstream parameters for estimating life-cycle emissions associated with alternative vehicle/fuel systems in the transportation sector, especially electric vehicles. The emission factors are typically expressed in grams of GHG or CAP per kWh of electricity generated by a specific power generation technology. This document describes our approach for updating and expanding GHG and CAP emission factors in the GREET (Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation) model developed at Argonne National Laboratory (see Wang 1999 and the GREET website at http://greet.es.anl.gov/main) for various power generation technologies. These GHG and CAP emissions are used to estimate the impact of electricity use by stationary and transportation applications on their fuel-cycle emissions. The electricity generation mixes and the fuel shares attributable to various combustion technologies at the national, regional and state levels are also updated in this document. The energy conversion efficiencies of electric generating units (EGUs) by fuel type and combustion technology are calculated on the basis of the lower heating values of each fuel, to be consistent with the basis used in GREET for transportation fuels. On the basis of the updated GHG and CAP emission factors and energy efficiencies of EGUs, the probability distribution functions (PDFs), which are functions that describe the relative likelihood for the emission factors and energy efficiencies as random variables to take on a given value by the integral of their own probability distributions, are updated using best-fit statistical curves to characterize the uncertainties associated with GHG and CAP emissions in life

  15. Geologic studies of deep natural gas resources

    USGS Publications Warehouse

    Dyman, T. S.; Kuuskraa, V.A.

    2001-01-01

    In 1995, the USGS estimated a mean resource of 114 trillion cubic feet of undiscovered technically recoverable natural gas in plays deeper than 15,000 feet/4,572 meters in onshore regions of the United States. This volume summarizes major conclusions of ongoing work. Chapters A and B address the areal extent of drilling and distribution of deep basins in the U.S. Chapter C summarizes distribution of deep sedimentary basins and potential for deep gas in the former Soviet Union. Chapters D and E are geochemical papers addressing source-rock issues and deep gas generation. Chapter F develops a probabilistic method for subdividing gas resources into depth slices, and chapter G analyzes the relative uncertainty of estimates of deep gas in plays in the Gulf Coast Region. Chapter H evaluates the mechanism of hydrogenation of deep, high-rank spent kerogen by water, with subsequent generation of methane-rich HC gas.

  16. New insights on timing of oil and gas generation in the central Gulf Coast interior zone based on hydrous-pyrolysis kinetic parameters

    USGS Publications Warehouse

    Lewan, Michael D.; Dutton, Shirley P.; Ruppel, Stephen C.; Hentz, Tucker F.

    2002-01-01

    Timing of oil and gas generation from Turonian and Smackover source rocks in the central Gulf CoastInterior Zone was determined in one-dimensional burial-history curves (BHCs) using hydrous-pyrolysis kinetic parameters. The results predict that basal Smackover source-rock intervals with Type-IIS kerogen completed oil generation between 121 and 99 Ma, and Turonian source-rocks with Type-II kerogen remain immature over most of the same area. The only exception to the latter occurs in the northwestern part of the Mississippi salt basin, where initial stages of oil generation have started as a result of higher thermal gradients. This maturity difference between Turonian and Smackover source rocks is predicted with present-day thermal gradients. Predicted oil generation prior to the Sabine and Monroe uplifts suggests that a significant amount of the oil emplaced in Cretaceous reservoirs of these uplifts would have been lost during periods of erosion. Hydrous-pyrolysis kineticparameters predict that cracking of Smackover oil to gas started 52 Ma, which postdates major uplift and erosional events of the Sabine and Monroe uplifts. This generated gas would accumulate and persist in these uplift areas as currently observed. The predicted timing of oil and gas generation with hydrous-pyrolysis kinetic parameters is in accordance with the observed scarcity of oil from Turonian source rocks, predominance of gas accumulations on the Sabine and Monroe uplifts, and predominance of oil accumulations along the northern rim of the Interior Zone.

  17. Next-generation polymer-electrolyte-membrane fuel cells using titanium foam as gas diffusion layer.

    PubMed

    Choi, Hyelim; Kim, Ok-Hee; Kim, Minhyoung; Choe, Heeman; Cho, Yong-Hun; Sung, Yung-Eun

    2014-05-28

    In spite of their high conversion efficiency and no emission of greenhouse gases, polymer electrolyte membrane fuel cells (PEMFCs) suffer from prohibitively high cost and insufficient life-span of their core component system, the membrane electrode assembly (MEA). In this paper, we are proposing Ti foam as a promising alternative electrode material in the MEA. Indeed, it showed a current density of 462 mA cm(-2), being ca. 166% higher than that with the baseline Toray 060 gas diffusion layer (GDL) (278 mA cm(-2)) with 200 ccm oxygen supply at 0.7 V, when used as the anode GDL, because of its unique three-dimensional strut structure promoting highly efficient catalytic reactions. Furthermore, it exhibits superior corrosion resistance with almost no thickness and weight changes in the accelerated corrosion test, as opposed to considerable reductions in the weight and thickness of the conventional GDL. We believe that this paper suggests profound implications in the commercialization of PEMFCs, because the metallic Ti foam provides a longer-term reliability and chemical stability, which can reduce the loss of Pt catalyst and, hence, the cost of PEMFCs.

  18. Impact of process design on greenhouse gas (GHG) generation by wastewater treatment plants.

    PubMed

    Bani Shahabadi, M; Yerushalmi, L; Haghighat, F

    2009-06-01

    The overall on-site and off-site greenhouse gas emissions by wastewater treatment plants (WWTPs) of food processing industry were estimated by using an elaborate mathematical model. Three different types of treatment processes including aerobic, anaerobic and hybrid anaerobic/aerobic processes were examined in this study. The overall on-site emissions were 1952, 1992, and 2435 kg CO2e/d while the off-site emissions were 1313, 4631, and 5205 kg CO2e/d for the aerobic, anaerobic and hybrid treatment systems, respectively, when treating a wastewater at 2000 kg BOD/d. The on-site biological processes made the highest contribution to GHG emissions in the aerobic treatment system while the highest emissions in anaerobic and hybrid treatment systems were obtained by off-site GHG emissions, mainly due to on-site material usage. Biogas recovery and reuse as fuel cover the total energy needs of the treatment plants for aeration, heating and electricity for all three types of operations, and considerably reduce GHG emissions by 512, 673, and 988 kg CO2e/d from a total of 3265, 6625, and 7640 kg CO2e/d for aerobic, anaerobic, and hybrid treatment systems, respectively. Considering the off-site GHG emissions, aerobic treatment is the least GHG producing type of treatment contrary to what has been reported in the literature.

  19. A parametric study of a gas-generator airturbo ramjet (ATR)

    NASA Technical Reports Server (NTRS)

    Snyder, C. A.

    1986-01-01

    Parametric engine performance calculations were carried out for an airturbo ramjet (ATR). A LOX-LH2 rocket powered turbine powered the compressor. The engine was flown over a typical flight path up to Mach 5 to show the effect of engine off design operation. The compressor design efficiency, compressor pressure ratio, rocket turbine efficiency, rocket turbine inlet temperature, and rocket chamber pressure were varied to show their effect on engine net thrust and specific impulse at Mach 5 cruise. Estimates of engine weights as a fucntion of the ratio of compressor air to rocket propellant flow and rocket champer pressure are also included. In general, the Mach 5 results indicate that increasing the amount of rocket gas produced increased thrust but decreased the specific impulse. The engine performance was fairly sensitive to rocket chamber pressure, especially at higher compressor pressure ratios. At higher compressor pressure ratios, the engine thrust was sensitive to turbine inlet temperature. At all compressor pressure ratios, the engine performance was not sensitive to compressor or turbine efficiency.

  20. A parametric study of a gas-generator airturbo ramjet (ATR)

    NASA Technical Reports Server (NTRS)

    Snyder, Christopher A.

    1986-01-01

    Parametric engine performance calculations were carried out for an airturbo ramjet (ATR). A LOX-LH2 rocket powered turbine powered the compressor. The engine was flown over a typical flight path up to Mach 5 to show the effect of engine off design operation. The compressor design efficiency, compressor pressure ratio, rocket turbine efficiency, rocket turbine inlet temperature, and rocket chamber pressure were varied to show their effect on engine net thrust and specific impulse at Mach 5 cruise. Estimates of engine weights as a function of the ratio of compressor air to rocket propellant flow and rocket chamber pressure are also included. In general, the Mach 5 results indicate that increasing the amount of rocket gas produced increased thrust but decreased the specific impulse. The engine performance was fairly sensitive to rocket chamber pressure, especially at higher compressor pressure ratios. At higher compressor pressure ratios, the engine thrust was sensitive to turbine inlet temperature. At all compressor pressure ratios, the engine performance was not sensitive to compressor or turbine efficiency.