Science.gov

Sample records for advanced variable cycle

  1. Variable cycle engines for advanced supersonic transports

    NASA Technical Reports Server (NTRS)

    Howlett, R. A.; Kozlowski, H.

    1975-01-01

    Variable Cycle Engines being studied for advanced commercial supersonic transports show potential for significant environmental and economic improvements relative to 1st generation SST engines. The two most promising concepts are: a Variable Stream Control Engine and a Variable Cycle Engine with a rear flow-control valve. Each concept utilizes variable components and separate burners to provide independent temperature and velocity control for two coannular flow streams. Unique fuel control techniques are combined with cycle characteristics that provide low fuel consumption, similar to a turbojet engine, for supersonic operation. This is accomplished while retaining the good subsonic performance features of a turbofan engine. A two-stream coannular nozzle shows potential to reduce jet noise to below FAR Part 36 without suppressors. Advanced burner concepts have the potential for significant reductions in exhaust emissions. In total, these unique engine concepts have the potential for significant overall improvements to the environmental and economic characteristics of advanced supersonic transports.

  2. Advanced supersonic propulsion study, phases 3 and 4. [variable cycle engines

    NASA Technical Reports Server (NTRS)

    Allan, R. D.; Joy, W.

    1977-01-01

    An evaluation of various advanced propulsion concepts for supersonic cruise aircraft resulted in the identification of the double-bypass variable cycle engine as the most promising concept. This engine design utilizes special variable geometry components and an annular exhaust nozzle to provide high take-off thrust and low jet noise. The engine also provides good performance at both supersonic cruise and subsonic cruise. Emission characteristics are excellent. The advanced technology double-bypass variable cycle engine offers an improvement in aircraft range performance relative to earlier supersonic jet engine designs and yet at a lower level of engine noise. Research and technology programs required in certain design areas for this engine concept to realize its potential benefits include refined parametric analysis of selected variable cycle engines, screening of additional unconventional concepts, and engine preliminary design studies. Required critical technology programs are summarized.

  3. Advanced Engine Cycles Analyzed for Turbofans With Variable-Area Fan Nozzles Actuated by a Shape Memory Alloy

    NASA Technical Reports Server (NTRS)

    Berton, Jeffrey J.

    2002-01-01

    Advanced, large commercial turbofan engines using low-fan-pressure-ratio, very high bypass ratio thermodynamic cycles can offer significant fuel savings over engines currently in operation. Several technological challenges must be addressed, however, before these engines can be designed. To name a few, the high-diameter fans associated with these engines pose a significant packaging and aircraft installation challenge, and a large, heavy gearbox is often necessary to address the differences in ideal operating speeds between the fan and the low-pressure turbine. Also, the large nacelles contribute aerodynamic drag penalties and require long, heavy landing gear when mounted on conventional, low wing aircraft. Nevertheless, the reduced fuel consumption rates of these engines are a compelling economic incentive, and fans designed with low pressure ratios and low tip speeds offer attractive noise-reduction benefits. Another complication associated with low-pressure-ratio fans is their need for variable flow-path geometry. As the design fan pressure ratio is reduced below about 1.4, an operational disparity is set up in the fan between high and low flight speeds. In other words, between takeoff and cruise there is too large a swing in several key fan parameters-- such as speed, flow, and pressure--for a fan to accommodate. One solution to this problem is to make use of a variable-area fan nozzle (VAFN). However, conventional, hydraulically actuated variable nozzles have weight, cost, maintenance, and reliability issues that discourage their use with low-fan-pressure-ratio engine cycles. United Technologies Research, in cooperation with NASA, is developing a revolutionary, lightweight, and reliable shape memory alloy actuator system that can change the on-demand nozzle exit area by up to 20 percent. This "smart material" actuation technology, being studied under NASA's Ultra-Efficient Engine Technology (UEET) Program and Revolutionary Concepts in Aeronautics (Rev

  4. Variable cycle engine

    SciTech Connect

    Adamson, A.P.; Sprunger, E.V.

    1980-09-16

    A variable cycle turboshaft engine includes a remote fan system and respective high and low pressure systems for selectively driving the fan system in such a manner as to provide VTOL takeoff capability and minimum specific fuel consumption (SFC) at cruise and loiter conditions. For takeoff the fan system is primarily driven by the relatively large low pressure system whose combustor receives the motive fluid from a core bypass duct and, for cruise and loiter conditions, the fan system is driven by both a relatively small high pressure core and the low pressure system with its combustor inoperative. A mixer is disposed downstream of the high pressure system for mixing the relatively cold air from the bypass duct and the relatively hot air from the core prior to its flow to the low pressure turbine.

  5. Supersonic variable-cycle engines

    NASA Technical Reports Server (NTRS)

    Willis, E. A.; Welliver, A. D.

    1976-01-01

    The evolution and current status of selected recent variable cycle engine (VCE) studies are reviewed, and how the results were influenced by airplane requirements is described. Promising VCE concepts are described, their designs are simplified and the potential benefits in terms of aircraft performance are identified. This includes range, noise, emissions, and the time and effort it may require to ensure technical readiness of sufficient depth to satisfy reasonable economic, performance, and environmental constraints. A brief overview of closely related, ongoing technology programs in acoustics and exhaust emissions is also presented. Realistic technology advancements in critical areas combined with well matched aircraft and selected VCE concepts can lead to significantly improved economic and environmental performance relative to first generation SST predictions.

  6. Low-speed wind-tunnel tests of a large scale blended arrow advanced supersonic transport model having variable cycle engines and vectoring exhaust nozzles

    NASA Technical Reports Server (NTRS)

    Parlett, L. P.; Shivers, J. P.

    1976-01-01

    A low-speed wind-tunnel investigation was conducted in a full-scale tunnel to determine the performance and static stability and control characteristics of a large-scale model of a blended-arrow advanced supersonic transport configuration incorporating variable-cycle engines and vectoring exhaust nozzles. Configuration variables tested included: (1) engine mode (cruise or low-speed), (2) engine exit nozzle deflection, (3) leading-edge flap geometry, and (4) trailing-edge flap deflection. Test variables included values of C sub micron from 0 to 0.38, values of angle of attack from -10 degrees to 30 degrees, values of angle of sideslip, from -5 degrees to 5 degrees, and values of Reynolds number, from 3.5 million to 6.8 million.

  7. Variable mixer propulsion cycle

    NASA Technical Reports Server (NTRS)

    Rundell, D. J.; Mchugh, D. P.; Foster, T.; Brown, R. H. (Inventor)

    1978-01-01

    A design technique, method and apparatus are delineated for controlling the bypass gas stream pressure and varying the bypass ratio of a mixed flow gas turbine engine in order to achieve improved performance. The disclosed embodiments each include a mixing device for combining the core and bypass gas streams. The variable area mixing device permits the static pressures of the core and bypass streams to be balanced prior to mixing at widely varying bypass stream pressure levels. The mixed flow gas turbine engine therefore operates efficiently over a wide range of bypass ratios and the dynamic pressure of the bypass stream is maintained at a level which will keep the engine inlet airflow matched to an optimum design level throughout a wide range of engine thrust settings.

  8. A preliminary design and analysis of an advanced heat-rejection system for an extreme altitude advanced variable cycle diesel engine installed in a high-altitude advanced research platform

    NASA Technical Reports Server (NTRS)

    Johnston, Richard P.

    1992-01-01

    Satellite surveillance in such areas as the Antarctic indicates that from time to time concentration of ozone grows and shrinks. An effort to obtain useful atmospheric data for determining the causes of ozone depletion would require a flight capable of reaching altitudes of at least 100,000 ft and flying subsonically during the sampling portion of the mission. A study of a heat rejection system for an advanced variable cycle diesel (AVCD) engine was conducted. The engine was installed in an extreme altitude, high altitude advanced research platform. Results indicate that the waste heat from an AVCD engine propulsion system can be rejected at the maximum cruise altitude of 120,000 ft. Fifteen performance points, reflecting the behavior of the engine as the vehicle proceeded through the mission, were used to characterize the heat exchanger operation. That portion of the study is described in a appendix titled, 'A Detailed Study of the Heat Rejection System for an Extreme Altitude Atmospheric Sampling Aircraft,' by a consultant, Mr. James Bourne, Lytron, Incorporated.

  9. Advanced Nuclear Fuel Cycle Options

    SciTech Connect

    Roald Wigeland; Temitope Taiwo; Michael Todosow; William Halsey; Jess Gehin

    2010-06-01

    A systematic evaluation has been conducted of the potential for advanced nuclear fuel cycle strategies and options to address the issues ascribed to the use of nuclear power. Issues included nuclear waste management, proliferation risk, safety, security, economics and affordability, and sustainability. The two basic strategies, once-through and recycle, and the range of possibilities within each strategy, are considered for all aspects of the fuel cycle including options for nuclear material irradiation, separations if needed, and disposal. Options range from incremental changes to today’s implementation to revolutionary concepts that would require the development of advanced nuclear technologies.

  10. Variable cycle gas turbine engines

    NASA Technical Reports Server (NTRS)

    Johnson, J. E.; Foster, T. (Inventor)

    1977-01-01

    A technique, method, and apparatus were designed for varying the bypass ratio and modulating the flow of a gas turbine engine in order to achieve improved mixed mission performance. Embodiments include gas flow control system for management of core and bypass stream pressure comprising diverter valve means downstream of the core engine to selectively mix or separate the core and bypass exhaust streams. The flow control system may also include variable geometry means for maintaining the engine inlet airflow at a matched design level at all flight velocities. Earth preferred embodiment thus may be converted from a high specific thrust mixed flow cycle at supersonic velocities to a lower specific thrust separated flow turbofan system at subsonic velocities with a high degree of flow variability in each mode of operation.

  11. Variable-cycle engines for supersonic cruise aircraft

    NASA Technical Reports Server (NTRS)

    Willis, E.

    1976-01-01

    Progress and the current status of the Variable Cycle Engine (VCE) study are reviewed with emphasis placed on the impact of technology advancements and design specifications. A large variety of VCE concepts are also examined.

  12. Advanced Fuel Cycle Cost Basis

    SciTech Connect

    D. E. Shropshire; K. A. Williams; W. B. Boore; J. D. Smith; B. W. Dixon; M. Dunzik-Gougar; R. D. Adams; D. Gombert; E. Schneider

    2008-03-01

    This report, commissioned by the U.S. Department of Energy (DOE), provides a comprehensive set of cost data supporting a cost analysis for the relative economic comparison of options for use in the Advanced Fuel Cycle Initiative (AFCI) Program. The report describes the AFCI cost basis development process, reference information on AFCI cost modules, a procedure for estimating fuel cycle costs, economic evaluation guidelines, and a discussion on the integration of cost data into economic computer models. This report contains reference cost data for 25 cost modules—23 fuel cycle cost modules and 2 reactor modules. The cost modules were developed in the areas of natural uranium mining and milling, conversion, enrichment, depleted uranium disposition, fuel fabrication, interim spent fuel storage, reprocessing, waste conditioning, spent nuclear fuel (SNF) packaging, long-term monitored retrievable storage, near surface disposal of low-level waste (LLW), geologic repository and other disposal concepts, and transportation processes for nuclear fuel, LLW, SNF, transuranic, and high-level waste.

  13. Advanced Fuel Cycle Cost Basis

    SciTech Connect

    D. E. Shropshire; K. A. Williams; W. B. Boore; J. D. Smith; B. W. Dixon; M. Dunzik-Gougar; R. D. Adams; D. Gombert

    2007-04-01

    This report, commissioned by the U.S. Department of Energy (DOE), provides a comprehensive set of cost data supporting a cost analysis for the relative economic comparison of options for use in the Advanced Fuel Cycle Initiative (AFCI) Program. The report describes the AFCI cost basis development process, reference information on AFCI cost modules, a procedure for estimating fuel cycle costs, economic evaluation guidelines, and a discussion on the integration of cost data into economic computer models. This report contains reference cost data for 26 cost modules—24 fuel cycle cost modules and 2 reactor modules. The cost modules were developed in the areas of natural uranium mining and milling, conversion, enrichment, depleted uranium disposition, fuel fabrication, interim spent fuel storage, reprocessing, waste conditioning, spent nuclear fuel (SNF) packaging, long-term monitored retrievable storage, near surface disposal of low-level waste (LLW), geologic repository and other disposal concepts, and transportation processes for nuclear fuel, LLW, SNF, and high-level waste.

  14. Advanced Fuel Cycle Cost Basis

    SciTech Connect

    D. E. Shropshire; K. A. Williams; W. B. Boore; J. D. Smith; B. W. Dixon; M. Dunzik-Gougar; R. D. Adams; D. Gombert; E. Schneider

    2009-12-01

    This report, commissioned by the U.S. Department of Energy (DOE), provides a comprehensive set of cost data supporting a cost analysis for the relative economic comparison of options for use in the Advanced Fuel Cycle Initiative (AFCI) Program. The report describes the AFCI cost basis development process, reference information on AFCI cost modules, a procedure for estimating fuel cycle costs, economic evaluation guidelines, and a discussion on the integration of cost data into economic computer models. This report contains reference cost data for 25 cost modules—23 fuel cycle cost modules and 2 reactor modules. The cost modules were developed in the areas of natural uranium mining and milling, conversion, enrichment, depleted uranium disposition, fuel fabrication, interim spent fuel storage, reprocessing, waste conditioning, spent nuclear fuel (SNF) packaging, long-term monitored retrievable storage, near surface disposal of low-level waste (LLW), geologic repository and other disposal concepts, and transportation processes for nuclear fuel, LLW, SNF, transuranic, and high-level waste.

  15. Variable pressure power cycle and control system

    DOEpatents

    Goldsberry, Fred L.

    1984-11-27

    A variable pressure power cycle and control system that is adjustable to a variable heat source is disclosed. The power cycle adjusts itself to the heat source so that a minimal temperature difference is maintained between the heat source fluid and the power cycle working fluid, thereby substantially matching the thermodynamic envelope of the power cycle to the thermodynamic envelope of the heat source. Adjustments are made by sensing the inlet temperature of the heat source fluid and then setting a superheated vapor temperature and pressure to achieve a minimum temperature difference between the heat source fluid and the working fluid.

  16. Study of an advanced variable-cycle diesel as applied to an RPV (remotely piloted vehicles). Final report, 11 August 1988-28 February 1989

    SciTech Connect

    Johnston, R.P.

    1989-05-01

    A variable-cycle diesel is examined for use in an unmanned long-endurance RPV. Engine-configuration studies are made and a possible installation arrangement developed. Installed performance projections are made, and a long endurance RPV mission fuel, installed engine weight and propeller performance estimates made along with several aircraft-installation drawings. It was found that the final engine configuration performed the specified mission with a total fuel and installed engine weight fraction of only 24% of the vehicle Take Off Gross Weight. The mission was evaluated at a cruise altitude of 65000 feet and an engine configuration suitable for use at 85000 feet was also investigated.

  17. Uncertainty Analyses of Advanced Fuel Cycles

    SciTech Connect

    Laurence F. Miller; J. Preston; G. Sweder; T. Anderson; S. Janson; M. Humberstone; J. MConn; J. Clark

    2008-12-12

    The Department of Energy is developing technology, experimental protocols, computational methods, systems analysis software, and many other capabilities in order to advance the nuclear power infrastructure through the Advanced Fuel Cycle Initiative (AFDI). Our project, is intended to facilitate will-informed decision making for the selection of fuel cycle options and facilities for development.

  18. Advanced regenerative absorption refrigeration cycles

    DOEpatents

    Dao, Kim

    1990-01-01

    Multi-effect regenerative absorption cycles which provide a high coefficient of performance (COP) at relatively high input temperatures. An absorber-coupled double-effect regenerative cycle (ADR cycle) (10) is provided having a single-effect absorption cycle (SEA cycle) (11) as a topping subcycle and a single-effect regenerative absorption cycle (1R cycle) (12) as a bottoming subcycle. The SEA cycle (11) includes a boiler (13), a condenser (21), an expansion device (28), an evaporator (31), and an absorber (40), all operatively connected together. The 1R cycle (12) includes a multistage boiler (48), a multi-stage resorber (51), a multisection regenerator (49) and also uses the condenser (21), expansion device (28) and evaporator (31) of the SEA topping subcycle (11), all operatively connected together. External heat is applied to the SEA boiler (13) for operation up to about 500 degrees F., with most of the high pressure vapor going to the condenser (21) and evaporator (31) being generated by the regenerator (49). The substantially adiabatic and isothermal functioning of the SER subcycle (12) provides a high COP. For higher input temperatures of up to 700 degrees F., another SEA cycle (111) is used as a topping subcycle, with the absorber (140) of the topping subcycle being heat coupled to the boiler (13) of an ADR cycle (10). The 1R cycle (12) itself is an improvement in that all resorber stages (50b-f) have a portion of their output pumped to boiling conduits (71a-f) through the regenerator (49), which conduits are connected to and at the same pressure as the highest pressure stage (48a) of the 1R multistage boiler (48).

  19. Stage-by-Stage and Parallel Flow Path Compressor Modeling for a Variable Cycle Engine, NASA Advanced Air Vehicles Program - Commercial Supersonic Technology Project - AeroServoElasticity

    NASA Technical Reports Server (NTRS)

    Kopasakis, George; Connolly, Joseph W.; Cheng, Larry

    2015-01-01

    This paper covers the development of stage-by-stage and parallel flow path compressor modeling approaches for a Variable Cycle Engine. The stage-by-stage compressor modeling approach is an extension of a technique for lumped volume dynamics and performance characteristic modeling. It was developed to improve the accuracy of axial compressor dynamics over lumped volume dynamics modeling. The stage-by-stage compressor model presented here is formulated into a parallel flow path model that includes both axial and rotational dynamics. This is done to enable the study of compressor and propulsion system dynamic performance under flow distortion conditions. The approaches utilized here are generic and should be applicable for the modeling of any axial flow compressor design accurate time domain simulations. The objective of this work is as follows. Given the parameters describing the conditions of atmospheric disturbances, and utilizing the derived formulations, directly compute the transfer function poles and zeros describing these disturbances for acoustic velocity, temperature, pressure, and density. Time domain simulations of representative atmospheric turbulence can then be developed by utilizing these computed transfer functions together with the disturbance frequencies of interest.

  20. Advanced Fuel Cycle Economic Sensitivity Analysis

    SciTech Connect

    David Shropshire; Kent Williams; J.D. Smith; Brent Boore

    2006-12-01

    A fuel cycle economic analysis was performed on four fuel cycles to provide a baseline for initial cost comparison using the Gen IV Economic Modeling Work Group G4 ECON spreadsheet model, Decision Programming Language software, the 2006 Advanced Fuel Cycle Cost Basis report, industry cost data, international papers, the nuclear power related cost study from MIT, Harvard, and the University of Chicago. The analysis developed and compared the fuel cycle cost component of the total cost of energy for a wide range of fuel cycles including: once through, thermal with fast recycle, continuous fast recycle, and thermal recycle.

  1. Physics challenges for advanced fuel cycle assessment

    SciTech Connect

    Giuseppe Palmiotti; Massimo Salvatores; Gerardo Aliberti

    2014-06-01

    Advanced fuel cycles and associated optimized reactor designs will require substantial improvements in key research area to meet new and more challenging requirements. The present paper reviews challenges and issues in the field of reactor and fuel cycle physics. Typical examples are discussed with, in some cases, original results.

  2. Variable-cycle reciprocating internal combustion engine

    SciTech Connect

    Johnston, R.P.

    1989-08-15

    This patent describes a variable cycle internal combustion engine. It comprises: a block the block having at least one cylinder chamber disposed therein; a pair of opposed pistons mounted in the cylinder chamber; a first rotating crankshaft and a second rotating crankshaft, each crankshaft connected to a different one of the pistons; means for synchronizing the speed and relative phase relationship of the crankshaft, the synchronizing means connected to at least one of the crankshafts; a harmonic gear drive assembly for selectively adjusting the rotation phase relationship between the crankshaft during operation of the engine. The harmonic gear drive assembly being connected to the synchronizing means.

  3. Mass transfer cycles in cataclysmic variables

    NASA Technical Reports Server (NTRS)

    King, A. R.; Frank, J.; Kolb, U.; Ritter, H.

    1995-01-01

    It is well known that in cataclysmic variables the mass transfer rate must fluctuate about the evolutionary mean on timescales too long to be directly observable. We show that limit-cycle behavior can occur if the radius change of the secondary star is sensitive to the instantaneous mass transfer rate. The only reasonable way in which such a dependence can arise is through irradiation of this star by the accreting component. The system oscillates between high states, in which irradiation causes slow expansion of the secondary and drives an elevated transfer rate, and low states, in which this star contracts.

  4. Systems Analyses of Advanced Brayton Cycles

    SciTech Connect

    A.D. Rao; D.J. Francuz; J.D. Maclay; J. Brouwer; A. Verma; M. Li; G.S. Samuelsen

    2008-09-30

    The main objective is to identify and assess advanced improvements to the Brayton Cycle (such as but not limited to firing temperature, pressure ratio, combustion techniques, intercooling, fuel or combustion air augmentation, enhanced blade cooling schemes) that will lead to significant performance improvements in coal based power systems. This assessment is conducted in the context of conceptual design studies (systems studies) that advance state-of-art Brayton cycles and result in coal based efficiencies equivalent to 65% + on natural gas basis (LHV), or approximately an 8% reduction in heat rate of an IGCC plant utilizing the H class steam cooled gas turbine. H class gas turbines are commercially offered by General Electric and Mitsubishi for natural gas based combined cycle applications with 60% efficiency (LHV) and it is expected that such machine will be offered for syngas applications within the next 10 years. The studies are being sufficiently detailed so that third parties will be able to validate portions or all of the studies. The designs and system studies are based on plants for near zero emissions (including CO{sub 2}). Also included in this program is the performance evaluation of other advanced technologies such as advanced compression concepts and the fuel cell based combined cycle. The objective of the fuel cell based combined cycle task is to identify the desired performance characteristics and design basis for a gas turbine that will be integrated with an SOFC in Integrated Gasification Fuel Cell (IGFC) applications. The goal is the conceptualization of near zero emission (including CO{sub 2} capture) integrated gasification power plants producing electricity as the principle product. The capability of such plants to coproduce H{sub 2} is qualitatively addressed. Since a total systems solution is critical to establishing a plant configuration worthy of a comprehensive market interest, a baseline IGCC plant scheme is developed and used to study

  5. Variability of Clouds Over a Solar Cycle

    NASA Technical Reports Server (NTRS)

    Yung, Yuk L.

    2002-01-01

    One of the most controversial aspects of climate studies is the debate over the natural and anthropogenic causes of climate change. Historical data strongly suggest that the Little Ice Age (from 1550 to 1850 AD when the mean temperature was colder by about 1 C) was most likely caused by variability of the sun and not greenhouse molecules (e.g., CO2). However, the known variability in solar irradiance and modulation of cosmic rays provides too little energy, by many orders of magnitude, to lead to climate changes in the troposphere. The conjecture is that there is a 'trigger mechanism'. This idea may now be subjected to a quantitative test using recent global datasets. Using the best available modern cloud data from International Satellite Cloud Climatology Project (ISCCP), Svensmark and Friis-Christensen found a correlation of a large variation (3-4%) in global cloud cover with the solar cycle. The work has been extended by Svensmark and Marsh and Svensmark. The implied forcing on climate is an order of magnitude greater than any previous claims. Are clouds the long sought trigger mechanism? This discovery is potentially so important that it should be corroborated by an independent database, and, furthermore, it must be shown that alternative explanations (i.e., El Nino) can be ruled out. We used the ISCCP data in conjunction with the Total Ozone Mapping Spectrometer (TOMS) data to carry out in in depth study of the cloud trigger mechanism.

  6. Advanced Nuclear Fuel Cycle Transitions: Optimization, Modeling Choices, and Disruptions

    NASA Astrophysics Data System (ADS)

    Carlsen, Robert W.

    Many nuclear fuel cycle simulators have evolved over time to help understan the nuclear industry/ecosystem at a macroscopic level. Cyclus is one of th first fuel cycle simulators to accommodate larger-scale analysis with it liberal open-source licensing and first-class Linux support. Cyclus also ha features that uniquely enable investigating the effects of modeling choices o fuel cycle simulators and scenarios. This work is divided into thre experiments focusing on optimization, effects of modeling choices, and fue cycle uncertainty. Effective optimization techniques are developed for automatically determinin desirable facility deployment schedules with Cyclus. A novel method fo mapping optimization variables to deployment schedules is developed. Thi allows relationships between reactor types and scenario constraints to b represented implicitly in the variable definitions enabling the usage o optimizers lacking constraint support. It also prevents wasting computationa resources evaluating infeasible deployment schedules. Deployed power capacit over time and deployment of non-reactor facilities are also included a optimization variables There are many fuel cycle simulators built with different combinations o modeling choices. Comparing results between them is often difficult. Cyclus flexibility allows comparing effects of many such modeling choices. Reacto refueling cycle synchronization and inter-facility competition among othe effects are compared in four cases each using combinations of fleet of individually modeled reactors with 1-month or 3-month time steps. There are noticeable differences in results for the different cases. The larges differences occur during periods of constrained reactor fuel availability This and similar work can help improve the quality of fuel cycle analysi generally There is significant uncertainty associated deploying new nuclear technologie such as time-frames for technology availability and the cost of buildin advanced reactors

  7. Recent Advances in GEO Water Cycle Activities

    NASA Astrophysics Data System (ADS)

    Lawford, R. G.

    2009-12-01

    Over the past few years GEO (Group on Earth Observations) efforts within the Water Societal Benefit Area (SBA) have been coordinated by the Science Committee of the former Integrated Global Observing Strategy Partnership (IGOS-P) IGWCO (Integrated Global Water Cycle Observations) theme. Within this framework a number of projects related to data system design, product development, and capacity building are being carried out. GEO has recently consolidated the Water SBA activities into three tasks, namely Droughts, Floods and Water Resource Management; Capacity Building for Water Resource Management (in Asia, Africa and the Americas); and Integrated Products for Water Resource Management and Research. In order to strengthen interactions with the GEO and its User Interface Committee, a Water Cycle Community of Practice (COP) was initiated. In addition, within the past year, the IGWCO Science Committee has decided to also function as a Community of Practice in collaboration with the existing Water Cycle COP. This overview will provide background and an update on the GEO Water SBA activities with an emphasis of the way in which these activities are being integrated within the three tasks. It will also describe activities that are planned for 2010 to facilitate this integration. Recent advances related to drought monitoring, capacity and network building, and observational and data systems will be highlighted. New water-related activities arising from collaborations between US GEO and Canada GEO, and through activities within the GEO Architecture and Data Committee, will also be described. This presentation will conclude with a longer-term outlook for water within the GEO framework and provide some guidance for interested experts on how they can become involved in helping to implement these plans.

  8. Fuel cell and advanced turbine power cycle

    SciTech Connect

    White, D.J.

    1995-10-19

    Solar Turbines, Incorporated (Solar) has a vested interest in the integration of gas turbines and high temperature fuel cells and in particular, solid oxide fuel cells (SOFCs). Solar has identified a parallel path approach to the technology developments needed for future products. The primary approach is to move away from the simple cycle industrial machines of the past and develop as a first step more efficient recuperated engines. This move was prompted by the recognition that the simple cycle machines were rapidly approaching their efficiency limits. Improving the efficiency of simple cycle machines is and will become increasingly more costly. Each efficiency increment will be progressively more costly than the previous step.

  9. A new data architecture for advancing life cycle assessment

    EPA Science Inventory

    IntroductionLife cycle assessment (LCA) has a technical architecture that limits data interoperability, transparency, and automated integration of external data. More advanced information technologies offer promise for increasing the ease with which information can be synthesized...

  10. Interannual variability in biochemistry of partially mixed estuaries: Dissolved silicate cycles in northern San Francisco Bay

    USGS Publications Warehouse

    Peterson, David H.; Cayan, Daniel R.; Festa, John F.

    1986-01-01

    Much of the interannual variability in partially mixed estuaries in dissolved inorganic nutrient and dissolved oxygen patterns results from an enhancement or reduction of their annual cycle (generally via climatic forcing). In northern San Francisco Bay estuary the annual cycle of dissolved silicate supply peaks in spring and the effect of phytoplankton removal peaks in fall. Because riverine silicate sources are enhanced in wet years and reduced in dry years, the annual silicate cycle is modified accordingly. Effects of phytoplankton removal are reduced and delayed in wet years and enhanced and advanced (seen earlier) in dry years. Similar reasoning can apply to interpreting and understanding other mechanisms and rates.

  11. Carbon cycle in advanced coal chemical engineering.

    PubMed

    Yi, Qun; Li, Wenying; Feng, Jie; Xie, Kechang

    2015-08-01

    This review summarizes how the carbon cycle occurs and how to reduce CO2 emissions in highly efficient carbon utilization from the most abundant carbon source, coal. Nowadays, more and more attention has been paid to CO2 emissions and its myriad of sources. Much research has been undertaken on fossil energy and renewable energy and current existing problems, challenges and opportunities in controlling and reducing CO2 emission with technologies of CO2 capture, utilization, and storage. The coal chemical industry is a crucial area in the (CO2 value chain) Carbon Cycle. The realization of clean and effective conversion of coal resources, improving the utilization and efficiency of resources, whilst reducing CO2 emissions is a key area for further development and investigation by the coal chemical industry. Under a weak carbon mitigation policy, the value and price of products from coal conversion are suggested in the carbon cycle. PMID:25978270

  12. Modeling and analysis of advanced binary cycles

    SciTech Connect

    Gawlik, K.

    1997-12-31

    A computer model (Cycle Analysis Simulation Tool, CAST) and a methodology have been developed to perform value analysis for small, low- to moderate-temperature binary geothermal power plants. The value analysis method allows for incremental changes in the levelized electricity cost (LEC) to be determined between a baseline plant and a modified plant. Thermodynamic cycle analyses and component sizing are carried out in the model followed by economic analysis which provides LEC results. The emphasis of the present work is on evaluating the effect of mixed working fluids instead of pure fluids on the LEC of a geothermal binary plant that uses a simple Organic Rankine Cycle. Four resources were studied spanning the range of 265{degrees}F to 375{degrees}F. A variety of isobutane and propane based mixtures, in addition to pure fluids, were used as working fluids. This study shows that the use of propane mixtures at a 265{degrees}F resource can reduce the LEC by 24% when compared to a base case value that utilizes commercial isobutane as its working fluid. The cost savings drop to 6% for a 375{degrees}F resource, where an isobutane mixture is favored. Supercritical cycles were found to have the lowest cost at all resources.

  13. Recent Advances on Solar Global Magnetism and Variability

    NASA Astrophysics Data System (ADS)

    Brun, A. S.; Browning, M. K.; Dikpati, M.; Hotta, H.; Strugarek, A.

    2015-12-01

    We discuss recent observational, theoretical and numerical progress made in understanding the solar global magnetism and its short and long term variability. We discuss the physical process thought to be at the origin of the solar magnetic field and its 22-yr cycle, namely dynamo action, and the nonlinear interplay between convection, rotation, radiation and magnetic field, yielding modulations of the solar constant or of the large scale flows such as the torsional oscillations. We also discuss the role of the field parity and dynamo families in explaining the complex multipolar structure of the solar global magnetic field. We then present some key MHD processes acting in the deep radiative interior and discuss the probable topology of a primordial field there. Finally we summarize how helioseismology has contributed to these recent advances and how it could contribute to resolving current unsolved problems in solar global dynamics and magnetism.

  14. Current Comparison of Advanced Nuclear Fuel Cycles

    SciTech Connect

    Steven Piet; Trond Bjornard; Brent Dixon; Robert Hill; Gretchen Matthern; David Shropshire

    2007-04-01

    This paper compares potential nuclear fuel cycle strategies – once-through, recycling in thermal reactors, sustained recycle with a mix of thermal and fast reactors, and sustained recycle with fast reactors. Initiation of recycle starts the draw-down of weapons-usable material and starts accruing improvements for geologic repositories and energy sustainability. It reduces the motivation to search for potential second geologic repository sites. Recycle in thermal-spectru

  15. Solar Ultraviolet Irradiance Variability During the Decline of Cycle 23

    NASA Astrophysics Data System (ADS)

    Snow, M. A.; McClintock, W. E.; Woods, T. N.; Harder, J. W.; Richard, E. C.

    2010-12-01

    Observations from the SOLar-STellar Irradiance Comparision Experiment (SOLSTICE) on the SOlar Radiation and Climate Experiment (SORCE) began in 2003 and continue through the present. This time period includes the decline of solar cycle 23 through solar minimum. SOLSTICE measures solar irradiance from 115 nm to 300 nm with a spectral resolution of 0.1 nm. The variability seen by SORCE SOLSTICE is greater than the variability recorded by the instruments on the Upper Atmosphere Research Satellite(UARS). This poster will describe the magnitude and uncertainty of solar irradiance variability in the ultraviolet part of the spectrum during the SORCE mission with comparisons to irradiance models based on UARS measurements.

  16. Advanced Supercritical Carbon Dioxide Brayton Cycle Development

    SciTech Connect

    Anderson, Mark; Sienicki, James; Moisseytsev, Anton; Nellis, Gregory; Klein, Sanford

    2015-10-21

    Fluids operating in the supercritical state have promising characteristics for future high efficiency power cycles. In order to develop power cycles using supercritical fluids, it is necessary to understand the flow characteristics of fluids under both supercritical and two-phase conditions. In this study, a Computational Fluid Dynamic (CFD) methodology was developed for supercritical fluids flowing through complex geometries. A real fluid property module was implemented to provide properties for different supercritical fluids. However, in each simulation case, there is only one species of fluid. As a result, the fluid property module provides properties for either supercritical CO2 (S-CO2) or supercritical water (SCW). The Homogeneous Equilibrium Model (HEM) was employed to model the two-phase flow. HEM assumes two phases have same velocity, pressure, and temperature, making it only applicable for the dilute dispersed two-phase flow situation. Three example geometries, including orifices, labyrinth seals, and valves, were used to validate this methodology with experimental data. For the first geometry, S-CO2 and SCW flowing through orifices were simulated and compared with experimental data. The maximum difference between the mass flow rate predictions and experimental measurements is less than 5%. This is a significant improvement as previous works can only guarantee 10% error. In this research, several efforts were made to help this improvement. First, an accurate real fluid module was used to provide properties. Second, the upstream condition was determined by pressure and density, which determines supercritical states more precise than using pressure and temperature. For the second geometry, the flow through labyrinth seals was studied. After a successful validation, parametric studies were performed to study geometric effects on the leakage rate. Based on these parametric studies, an optimum design strategy for the see

  17. Assessment for advanced fuel cycle options in CANDU

    SciTech Connect

    Morreale, A.C.; Luxat, J.C.; Friedlander, Y.

    2013-07-01

    The possible options for advanced fuel cycles in CANDU reactors including actinide burning options and thorium cycles were explored and are feasible options to increase the efficiency of uranium utilization and help close the fuel cycle. The actinide burning TRUMOX approach uses a mixed oxide fuel of reprocessed transuranic actinides from PWR spent fuel blended with natural uranium in the CANDU-900 reactor. This system reduced actinide content by 35% and decreased natural uranium consumption by 24% over a PWR once through cycle. The thorium cycles evaluated used two CANDU-900 units, a generator and a burner unit along with a driver fuel feedstock. The driver fuels included plutonium reprocessed from PWR, from CANDU and low enriched uranium (LEU). All three cycles were effective options and reduced natural uranium consumption over a PWR once through cycle. The LEU driven system saw the largest reduction with a 94% savings while the plutonium driven cycles achieved 75% savings for PWR and 87% for CANDU. The high neutron economy, online fuelling and flexible compact fuel make the CANDU system an ideal reactor platform for many advanced fuel cycles.

  18. Brayton cycle solarized advanced gas turbine

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Described is the development of a Brayton Engine/Generator Set for solar thermal to electrical power conversion, authorized under DOE/NASA Contract DEN3-181. The objective was to design, fabricate, assemble, and test a small, hybrid, 20-kW Brayton-engine-powered generator set. The latter, called a power conversion assembly (PCA), is designed to operate with solar energy obtained from a parobolic dish concentrator, 11 meters in diameter, or with fossil energy supplied by burning fuels in a combustor, or by a combination of both (hybrid model). The CPA consists of the Brayton cycle engine, a solar collector, a belt-driven 20-kW generator, and the necessary control systems for automatic operation in solar-only, fuel-only, and hybrid modes to supply electrical power to a utility grid. The original configuration of the generator set used the GTEC Model GTP36-51 gas turbine engine for the PCA prime mover. However, subsequent development of the GTEC Model AGT101 led to its selection as the powersource for the PCA. Performance characteristics of the latter, thermally coupled to a solar collector for operation in the solar mode, are presented. The PCA was successfully demonstrated in the fuel-only mode at the GTEC Phoenix, Arizona, facilities prior to its shipment to Sandia National Laboratory in Albuquerque, New Mexico, for installation and testing on a test bed concentractor (parabolic dish). Considerations relative to Brayton-engine development using the all-ceramic AGT101 when it becomes available, which would satisfy the DOE heat engine efficiency goal of 35 to 41 percent, are also discussed in the report.

  19. Variable Cycle Engine Technology Program Planning and Definition Study

    NASA Technical Reports Server (NTRS)

    Westmoreland, J. S.; Stern, A. M.

    1978-01-01

    The variable stream control engine, VSCE-502B, was selected as the base engine, with the inverted flow engine concept selected as a backup. Critical component technologies were identified, and technology programs were formulated. Several engine configurations were defined on a preliminary basis to serve as demonstration vehicles for the various technologies. The different configurations present compromises in cost, technical risk, and technology return. Plans for possible variably cycle engine technology programs were formulated by synthesizing the technology requirements with the different demonstrator configurations.

  20. Component test program for variable-cycle engines

    NASA Technical Reports Server (NTRS)

    Powers, A. G.; Whitlow, J. B.; Stitt, L. E.

    1976-01-01

    Variable cycle engine (VCE) concepts for a supersonic cruise aircraft were studied. These VCE concepts incorporate unique critical components and flow path arrangements that provide good performance at both supersonic and subsonic cruise and appear to be economically and environmentally viable. Certain technologies were identified as critical to the successful development of these engine concepts and require considerable development and testing. The feasibility and readiness of the most critical VCE technologies, was assessed, a VCE component test program was initiated. The variable stream control engine (VSCE) component test program, tested and evaluated an efficient low emission duct burner and a quiet coannular ejector nozzle at the rear of a rematched F100 engine.

  1. Advanced Turbine System Program: Phase 2 cycle selection

    SciTech Connect

    Latcovich, J.A. Jr.

    1995-10-01

    The objectives of the Advanced Turbine System (ATS) Phase 2 Program were to define a commercially attractive ATS cycle and to develop the necessary technologies required to meet the ATS Program goals with this cycle. This program is part of an eight-year Department of Energy, Fossil Energy sponsored ATS Program to make a significant improvement in natural gas-fired power generation plant efficiency while providing an environmentally superior and cost-effective system.

  2. Coupled G-Mode Intersections and Solar-Cycle Variability

    NASA Astrophysics Data System (ADS)

    Juckett, David A.

    2010-03-01

    Wolff ( Astrophys. J. 193, 721, 1974) introduced the concept of g-mode coupling within the solar interior. Subsequently, Wolff developed a more quantitative model invoking a reciprocal interaction between coupled g modes and burning in the solar core. Coupling is proposed to occur for constant values of the spherical harmonic degree [ ℓ] creating rigidly rotating structures denoted as sets( ℓ). Power would be concentrated near the core and the top of radiative zone [RZ] in narrow intervals of longitude on opposite sides of the Sun. Sets( ℓ) would migrate retrograde in the RZ as function of ℓ and their intersections would deposit extra energy at the top of the RZ. It is proposed that this enhances sunspot eruptions at particular longitudes and at regular time intervals. Juckett and Wolff ( Solar Phys. 252, 247, 2008) detected this enhancement by viewing selected spherical harmonics of sunspot patterns within stackplots twisted into the relative rotational frames of various sets( ℓ). In subsequent work, the timings of the set( ℓ) intersections were compared to the sub-decadal variability of the sunspot cycle. Seventeen sub-decadal intersection frequencies (0.63 - 7.0 year) were synchronous with 17 frequencies in the sunspot time-series with a mean correlation of 0.96. Six additional non-11-year frequencies (periods of 8.0 to 28.7 year) are now shown to be nearly synchronous between sunspot variability and the model. Two additional intersections have the same frequency as the solar cycle itself and peak during the rising phase of the solar cycle. This may be partly responsible for cycle asymmetry. These results are evidence that some of the solar-cycle variability may be attributable to deterministic components that are intermixed with a broad-spectrum stochastic and long-term chaotic background.

  3. Evolution dynamics of tropical ocean-atmosphere annual cycle variability

    SciTech Connect

    Nigam, S.; Chao, Y.

    1996-12-01

    The structure of ocean-atmosphere annual cycle variability is extracted from the revised Comprehensive Ocean-Atmosphere Data Set SSTs, surface winds, and the latent heat (LH) and net shortwave (SW) surface fluxes using the covariance-based rotated principal component analysis method. The coupled annual cycle variability is concisely described using two modes that are in temporal quadrature. The first, peaking in June/July (and December/January), represents monsoonal flow onto Indochina, Central America, and western Africa. The second mode peaks in September/October and March/April when it represents the extreme phases of the SST annual cycle in the eastern oceans. Analysis of the surface momentum balance in the Pacific cold tongue core shows the equatorial flow, and in particular the zonal wind, to be dynamically consistent with the SST gradient during both the cold tongue`s nascent (June/July) and mature (September/October) phases; the dynamical consistency improves when the impact of nearsurface static stability variation on horizontal momentum dissipation is also considered. Evolution structure of the extracted annual cycle, moreover, shows the easterly wind tendency to lead SST cooling in the off-coastal zone. Taken together, these findings suggest that the Pacific cold tongue westward expansion results from local interaction of the zonal wind and zonal SST gradient, as encapsulated in the proposed {open_quotes}westward expansion hypothesis{close_quotes} - a simple analytic model of which is also presented. 29 refs., 10 figs.

  4. Evaluation of undeveloped rocket engine cycle applications to advanced transportation

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Undeveloped pump-fed, liquid propellant rocket engine cycles were assessed and evaluated for application to Next Manned Transportation System (NMTS) vehicles, which would include the evolving Space Transportation System (STS Evolution), the Personnel Launch System (PLS), and the Advanced Manned Launch System (AMLS). Undeveloped engine cycles selected for further analysis had potential for increased reliability, more maintainability, reduced cost, and improved (or possibly level) performance when compared to the existing SSME and proposed STME engines. The split expander (SX) cycle, the full flow staged combustion (FFSC) cycle, and a hybrid version of the FFSC, which has a LOX expander drive for the LOX pump, were selected for definition and analysis. Technology requirements and issues were identified and analyses of vehicle systems weight deltas using the SX and FFSC cycles in AMLS vehicles were performed. A strawman schedule and cost estimate for FFSC subsystem technology developments and integrated engine system demonstration was also provided.

  5. Advances in Understanding Decadal Climate Variability

    NASA Technical Reports Server (NTRS)

    Busalacchi, Antonio J.

    1999-01-01

    Recently, a joint Brazil-France-U.S. program, known as PIRATA (Pilot Research moored Array in the Tropical Atlantic), was proposed to begin the deployment of moored measurement platforms in the tropical Atlantic in order to enhance the existing observational data base and subsequent understanding of the processes by which the ocean and atmosphere couple in key regions of the tropical Atlantic Ocean. Empirical studies have suggested that there are strong relationships between tropical Atlantic upper ocean variability, SST, ocean-atmosphere coupling and regional climate variability. During the early 1980's a coordinated set of surface wind, subsurface thermal structure, and subsurface current observations were obtained as part of the U.S.-France SEQUAL-FOCAL process experiment designed to observe the seasonal response of the tropical Atlantic Ocean to surface forcing. Since that time, however, the observational data base for the tropical Atlantic Ocean has disintegrated to a few ship-tracks measuring ocean temperatures and a small collection of tide gauge stations measuring sea level. A more comprehensive set of observations, modeling and empirical studies is now in order to make progress on understanding the regional climate variability. The proposed PIRATA program will use mooring platforms similar to the tropical Pacific Ocean TAO array to measure surface fluxes of momentum and heat and the corresponding changes in the upper ocean thermal structure. It is anticipated that the oceanic data from this monitoring array will also be used in a predictive mode for initialization studies of regional coupled climate models. Of particular interest are zonal and meridional modes of ocean-atmosphere variability within the tropical Atlantic basin that have significant impacts on the regional climate of the bordering continents.

  6. Advances in Understanding Decadal Climate Variability

    NASA Technical Reports Server (NTRS)

    Busalaacchi, Antonio J.

    1998-01-01

    Recently, a joint Brazil-France-U.S. program, known as PIRATA (Pilot Research moored Array in the Tropical Atlantic), was proposed to begin the deployment of moored measurement platforms in the tropical Atlantic in order to enhance the existing observational data base and subsequent understanding of the processes by which the ocean and atmosphere couple in key regions of the tropical Atlantic Ocean. Empirical studies have suggested that there are strong relationships between tropical Atlantic upper ocean variability, SST, ocean-atmosphere coupling and regional climate variability. During the early 1980's a coordinated set of surface wind, subsurface thermal structure, and subsurface current observations were obtained as part of the U.S.-France SEQUAL- FOCAL process experiment designed to observe the seasonal response of the tropical Atlantic Ocean to surface forcing. Since that time, however, the observational data base for the tropical Atlantic Ocean has disintegrated to a few shiptracks measuring ocean temperatures and a small collection of tide gauge stations measuring sea level. A more comprehensive set of observations, modeling and empirical studies is now in order to make progress on understanding the regional climate variability. The proposed PIRATA program will use mooring platforms similar to the tropical Pacific Ocean TAO array to measure surface fluxes of momentum and heat and the corresponding changes in the upper ocean thermal structure. It is anticipated that the oceanic data from this monitoring array will also be used in a predictive mode for initialization studies of regional coupled climate models. Of particular interest are zonal and meridional modes of ocean-atmosphere variability within the tropical Atlantic basin that have significant impacts on the regional climate of the bordering continents.

  7. Experimental investigation of an advanced adsorption refrigeration cycle

    SciTech Connect

    Saha, B.B.; Kashiwagi, Takao

    1997-12-31

    Experimental measurements are made for a silica gel-water advanced absorption refrigeration chiller (1.2-kW [4,095-Btu/h] cooling capacity) to evaluate its performance under different temperature and adsorption/desorption cycle time conditions. This paper describes the operating principle of the chiller, outlines the experimental hardware, and discusses results obtained by varying the cooling and hot water inlet temperatures and adsorption/desorption cycle times, as well as their agreement with the simulated results given by a lumped parameter model. The chiller performance is analyzed in terms of cooling capacity and coefficient of performance (COP). Excellent qualitative agreement was obtained between the experimental data and simulated results. The results showed the advanced three-stage cycle to be particularly well suited for operation with low-grade-temperature waste heat as the driving source, since it worked with small regenerating temperature lifts (heat source-heat sink temperature) of 10 to 30 K.

  8. Steam turbine development for advanced combined cycle power plants

    SciTech Connect

    Oeynhausen, H.; Bergmann, D.; Balling, L.; Termuehlen, H.

    1996-12-31

    For advanced combined cycle power plants, the proper selection of steam turbine models is required to achieve optimal performance. The advancements in gas turbine technology must be followed by advances in the combined cycle steam turbine design. On the other hand, building low-cost gas turbines and steam turbines is desired which, however, can only be justified if no compromise is made in regard to their performance. The standard design concept of two-casing single-flow turbines seems to be the right choice for most of the present and future applications worldwide. Only for very specific applications it might be justified to select another design concept as a more suitable option.

  9. "ATLAS" Advanced Technology Life-cycle Analysis System

    NASA Technical Reports Server (NTRS)

    Lollar, Louis F.; Mankins, John C.; ONeil, Daniel A.

    2004-01-01

    Making good decisions concerning research and development portfolios-and concerning the best systems concepts to pursue - as early as possible in the life cycle of advanced technologies is a key goal of R&D management This goal depends upon the effective integration of information from a wide variety of sources as well as focused, high-level analyses intended to inform such decisions Life-cycle Analysis System (ATLAS) methodology and tool kit. ATLAS encompasses a wide range of methods and tools. A key foundation for ATLAS is the NASA-created Technology Readiness. The toolkit is largely spreadsheet based (as of August 2003). This product is being funded by the Human and Robotics The presentation provides a summary of the Advanced Technology Level (TRL) systems Technology Program Office, Office of Exploration Systems, NASA Headquarters, Washington D.C. and is being integrated by Dan O Neil of the Advanced Projects Office, NASA/MSFC, Huntsville, AL

  10. Steady-State Analysis Model for Advanced Fuel Cycle Schemes.

    2008-03-17

    Version 00 SMAFS was developed as a part of the study, "Advanced Fuel Cycles and Waste Management", which was performed during 2003-2005 by an ad-hoc expert group under the Nuclear Development Committee in the OECD/NEA. The model was designed for an efficient conduct of nuclear fuel cycle scheme cost analyses. It is simple, transparent and offers users the capability to track down cost analysis results. All the fuel cycle schemes considered in the model aremore » represented in a graphic format and all values related to a fuel cycle step are shown in the graphic interface, i.e., there are no hidden values embedded in the calculations. All data on the fuel cycle schemes considered in the study including mass flows, waste generation, cost data, and other data such as activities, decay heat and neutron sources of spent fuel and high-level waste along time are included in the model and can be displayed. The user can easily modify values of mass flows and/or cost parameters and see corresponding changes in the results. The model calculates: front-end fuel cycle mass flows such as requirements of enrichment and conversion services and natural uranium; mass of waste based on the waste generation parameters and the mass flow; and all costs.« less

  11. Highly Variable Cycle Exhaust Model Test (HVC10)

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda; Wernet, Mark; Podboy, Gary; Bozak, Rick

    2010-01-01

    Results from acoustic and flow-field studies using the Highly Variable Cycle Exhaust (HVC) model were presented. The model consisted of a lobed mixer on the core stream, an elliptic nozzle on the fan stream, and an ejector. For baseline comparisons, the fan nozzle was replaced with a round nozzle and the ejector doors were removed from the model. Acoustic studies showed far-field noise levels were higher for the HVC model with the ejector than for the baseline configuration. Results from Particle Image Velocimetry (PIV) studies indicated that large flow separation regions occurred along the ejector doors, thus restricting flow through the ejector. Phased array measurements showed noise sources located near the ejector doors for operating conditions where tones were present in the acoustic spectra.

  12. Waste Management Planned for the Advanced Fuel Cycle Facility

    SciTech Connect

    Soelberg

    2007-09-01

    The U.S. Department of Energy (DOE) Global Nuclear Energy Partnership (GNEP) program has been proposed to develop and employ advanced technologies to increase the proliferation resistance of spent nuclear fuels, recover and reuse nuclear fuel resources, and reduce the amount of wastes requiring permanent geological disposal. In the initial GNEP fuel cycle concept, spent nuclear fuel is to be reprocessed to separate re-useable transuranic elements and uranium from waste fission products, for fabricating new fuel for fast reactors. The separated wastes would be converted to robust waste forms for disposal. The Advanced Fuel Cycle Facility (AFCF) is proposed by DOE for developing and demonstrating spent nuclear fuel recycling technologies and systems. The AFCF will include capabilities for receiving and reprocessing spent fuel and fabricating new nuclear fuel from the reprocessed spent fuel. Reprocessing and fuel fabrication activities will generate a variety of radioactive and mixed waste streams. Some of these waste streams are unique and unprecedented. The GNEP vision challenges traditional U.S. radioactive waste policies and regulations. Product and waste streams have been identified during conceptual design. Waste treatment technologies have been proposed based on the characteristics of the waste streams and the expected requirements for the final waste forms. Results of AFCF operations will advance new technologies that will contribute to safe and economical commercial spent fuel reprocessing facilities needed to meet the GNEP vision. As conceptual design work and research and design continues, the waste management strategies for the AFCF are expected to also evolve.

  13. Variable C : N : P stoichiometry of dissolved organic matter cycling in the Community Earth System Model

    DOE PAGESBeta

    Letscher, R. T.; Moore, J. K.; Teng, Y. -C.; Primeau, F.

    2015-01-12

    Dissolved organic matter (DOM) plays an important role in the ocean's biological carbon pump by providing an advective/mixing pathway for ~ 20% of export production. DOM is known to have a stoichiometry depleted in nitrogen (N) and phosphorus (P) compared to the particulate organic matter pool, a fact that is often omitted from biogeochemical ocean general circulation models. However the variable C : N : P stoichiometry of DOM becomes important when quantifying carbon export from the upper ocean and linking the nutrient cycles of N and P with that of carbon. Here we utilize recent advances in DOM observationalmore » data coverage and offline tracer-modeling techniques to objectively constrain the variable production and remineralization rates of the DOM C : N : P pools in a simple biogeochemical-ocean model of DOM cycling. The optimized DOM cycling parameters are then incorporated within the Biogeochemical Elemental Cycling (BEC) component of the Community Earth System Model (CESM) and validated against the compilation of marine DOM observations. The optimized BEC simulation including variable DOM C : N : P cycling was found to better reproduce the observed DOM spatial gradients than simulations that used the canonical Redfield ratio. Global annual average export of dissolved organic C, N, and P below 100 m was found to be 2.28 Pg C yr-1 (143 Tmol C yr-1, 16.4 Tmol N yr-1, and 1 Tmol P yr-1, respectively, with an average export C : N : P stoichiometry of 225 : 19 : 1 for the semilabile (degradable) DOM pool. Dissolved organic carbon (DOC) export contributed ~ 25% of the combined organic C export to depths greater than 100 m.« less

  14. Variable C : N : P stoichiometry of dissolved organic matter cycling in the Community Earth System Model

    DOE PAGESBeta

    Letscher, R. T.; Moore, J. K.; Teng, Y. -C.; Primeau, F.

    2014-06-16

    Dissolved organic matter (DOM) plays an important role in the ocean's biological carbon pump by providing an advective/mixing pathway for ~ 20% of export production. DOM is known to have a stoichiometry depleted in nitrogen (N) and phosphorus (P) compared to the particulate organic matter pool, a~fact that is often omitted from biogeochemical-ocean general circulation models. However the variable C : N : P stoichiometry of DOM becomes important when quantifying carbon export from the upper ocean and linking the nutrient cycles of N and P with that of carbon. Here we utilize recent advances in DOM observational data coveragemore » and offline tracer-modeling techniques to objectively constrain the variable production and remineralization rates of the DOM C / N / P pools in a simple biogeochemical-ocean model of DOM cycling. The optimized DOM cycling parameters are then incorporated within the Biogeochemical Elemental Cycling (BEC) component of the Community Earth System Model and validated against the compilation of marine DOM observations. The optimized BEC simulation including variable DOM C : N : P cycling was found to better reproduce the observed DOM spatial gradients than simulations that used the canonical Redfield ratio. Global annual average export of dissolved organic C, N, and P below 100 m was found to be 2.28 Pg C yr-1 (143 Tmol C yr-1), 16.4 Tmol N yr-1, and 1 Tmol P yr-1, respectively with an average export C : N : P stoichiometry of 225 : 19 : 1 for the semilabile (degradable) DOM pool. DOC export contributed ~ 25% of the combined organic C export to depths greater than 100 m.« less

  15. Advanced combustion turbines and cycles: An EPRI perspective

    SciTech Connect

    Touchton, G.; Cohn, A.

    1995-10-01

    EPRI conducts a broad program of research in combustion turbine technology on behalf of its funders which is directed toward improving their competitive positions through lower cost of generation and risk mitigation. The major areas of EPRI interest are: (1) Combustion Turbine Technology Development, Assessment, and Procurement Information and Products. (2) Risk mitigation of emerging combustion turbines through durability surveillance. (3) Existing Fleet Management and Improvement Technology. In the context of the DOE ATS Review, the present paper will address new advanced turbines and cycles and durability surveillance, of emerging combustion turbines. It will touch on existing fleet management and improvement technology as appropriate.

  16. High efficiency fuel cell/advanced turbine power cycles

    SciTech Connect

    Morehead, H.

    1995-10-19

    An outline of the Westinghouse high-efficiency fuel cell/advanced turbine power cycle is presented. The following topics are discussed: The Westinghouse SOFC pilot manufacturing facility, cell scale-up plan, pressure effects on SOFC power and efficiency, sureCell versus conventional gas turbine plants, sureCell product line for distributed power applications, 20 MW pressurized-SOFC/gas turbine power plant, 10 MW SOFC/CT power plant, sureCell plant concept design requirements, and Westinghouse SOFC market entry.

  17. Life-cycle cost analysis of advanced design mixer pump

    SciTech Connect

    Hall, M.N., Westinghouse Hanford

    1996-07-23

    This analysis provides cost justification for the Advanced Design Mixer Pump program based on the cost benefit to the Hanford Site of 4 mixer pump systems defined in terms of the life-cycle cost.A computer model is used to estimate the total number of service hours necessary for each mixer pump to operate over the 20-year retrieval sequence period for single-shell tank waste. This study also considered the double-shell tank waste retrieved prior to the single-shell tank waste which is considered the initial retrieval.

  18. A Hydrological Perspective to Advance Understanding of the Water Cycle

    NASA Astrophysics Data System (ADS)

    Berghuijs, W.

    2014-12-01

    In principle hydrologists are scientists that study relationships within the water cycle. Yet, current technology makes it tempting for hydrology students to lose their "hydrological perspective" and become instead full-time computer programmers or statisticians. I assert that students should ensure their hydrological perspective thrives, notwithstanding the importance and possibilities of current technology. This perspective is necessary to advance the science of hydrology. As other hydrologists have pondered similar views before, I make no claims of originality here. I just hope that in presenting my perspective on this issue I may spark the interest of other early career hydrologists.

  19. Carbon Cycle Variability Due to the Atlantic Meridional Overturning Circulation

    NASA Astrophysics Data System (ADS)

    McKinley, G. A.; Breeden, M.

    2014-12-01

    The North Atlantic is the most intense region of CO2 uptake by the world oceans. Though characterization of the mean sink is robust across methodologies [1], a detailed understanding of variability remains lacking, seriously complicating interpretation of observations [2,3]. We investigate the causes of decadal scale variability in the North Atlantic carbon cycle using a regional numerical simulation driven by realistic climate for 1948-2013 and preindustrial atmospheric pCO2. Modeled decadal-timescale variability in air-sea CO2 fluxes and surface ocean pCO2 are dominantly controlled by basin-averaged sea surface temperature (SST). This SST signal is composed of two parts: the Atlantic Multidecadal Oscillation (AMO), associated with the model AMOC, and a positive trend. AMO dominates long-term pCO2 variability, with positive AMO leading to pCO2 declines in the subpolar gyre and pCO2 increases in the subtropical gyre. Decomposition of pCO2 into chemical (pCO2-chem) and temperature (pCO2-SST) drivers is instructive. Maximum positive AMO causes subpolar pCO2-SST to increase by ~10 uatm, but also for pCO2-chem to decline by ~20 uatm. Reduced subpolar pCO2-chem is due to reduced supply of dissolved inorganic carbon (DIC) by winter deep mixing and to enhanced DIC horizontal divergence. On net, positive AMO substantially depresses subpolar North Atlantic pCO2. AMO had maximum negative amplitude in the 1980s and maximum positive amplitude in the mid-2000s, which coincides with the observed record of surface ocean pCO2 [2]. This model suggests that the changing sign of AMO drove trends in the natural component of surface ocean pCO2 of approximately -7 uatm / decade in the subpolar gyre since the 1980s. This trend is significant in comparison to observed changes in surface ocean pCO2 [3], and thus impacts our understanding of the changing ocean carbon sink in this critical region. [1] Schuster et at 2013 [2] McKinley et al. 2011, McKinley and Fay 2013 [3] Metzl et al. 2010

  20. Energy Conversion Advanced Heat Transport Loop and Power Cycle

    SciTech Connect

    Oh, C. H.

    2006-08-01

    The Department of Energy and the Idaho National Laboratory are developing a Next Generation Nuclear Plant (NGNP) 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. Many aspects of the NGNP must be researched and developed in order to make recommendations on the final design of the plant. Parameters such as working conditions, cycle components, working fluids, and power conversion unit configurations must be understood. Three configurations of the power conversion unit were demonstrated in this study. A three-shaft design with 3 turbines and 4 compressors, a combined cycle with a Brayton top cycle and a Rankine bottoming cycle, and a reheated cycle with 3 stages of reheat were investigated. An intermediate heat transport loop for transporting process heat to a High Temperature Steam Electrolysis (HTSE) hydrogen production plant was used. Helium, CO2, and an 80% nitrogen, 20% helium mixture (by weight) were studied to determine the best working fluid in terms cycle efficiency and development cost. In each of these configurations the relative component size were estimated for the different working fluids. The relative size of the turbomachinery was measured by comparing the power input/output of the component. For heat exchangers the volume was computed and compared. Parametric studies away from the baseline values of the three-shaft and combined cycles were performed to determine the effect of varying conditions in the cycle. This gives some insight into the sensitivity of these cycles to various

  1. Continuously variable transmission: Assessment of applicability to advance electric vehicles

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.; Parker, R. J.

    1981-01-01

    A brief historical account of the evolution of continuously variable transmissions (CVT) for automotive use is given. The CVT concepts which are potentially suitable for application with electric and hybrid vehicles are discussed. The arrangement and function of several CVT concepts are cited along with their current developmental status. The results of preliminary design studies conducted on four CVT concepts for use in advanced electric vehicles are discussed.

  2. Advanced Fuel Cycle Economic Tools, Algorithms, and Methodologies

    SciTech Connect

    David E. Shropshire

    2009-05-01

    The Advanced Fuel Cycle Initiative (AFCI) Systems Analysis supports engineering economic analyses and trade-studies, and requires a requisite reference cost basis to support adequate analysis rigor. In this regard, the AFCI program has created a reference set of economic documentation. The documentation consists of the “Advanced Fuel Cycle (AFC) Cost Basis” report (Shropshire, et al. 2007), “AFCI Economic Analysis” report, and the “AFCI Economic Tools, Algorithms, and Methodologies Report.” Together, these documents provide the reference cost basis, cost modeling basis, and methodologies needed to support AFCI economic analysis. The application of the reference cost data in the cost and econometric systems analysis models will be supported by this report. These methodologies include: the energy/environment/economic evaluation of nuclear technology penetration in the energy market—domestic and internationally—and impacts on AFCI facility deployment, uranium resource modeling to inform the front-end fuel cycle costs, facility first-of-a-kind to nth-of-a-kind learning with application to deployment of AFCI facilities, cost tradeoffs to meet nuclear non-proliferation requirements, and international nuclear facility supply/demand analysis. The economic analysis will be performed using two cost models. VISION.ECON will be used to evaluate and compare costs under dynamic conditions, consistent with the cases and analysis performed by the AFCI Systems Analysis team. Generation IV Excel Calculations of Nuclear Systems (G4-ECONS) will provide static (snapshot-in-time) cost analysis and will provide a check on the dynamic results. In future analysis, additional AFCI measures may be developed to show the value of AFCI in closing the fuel cycle. Comparisons can show AFCI in terms of reduced global proliferation (e.g., reduction in enrichment), greater sustainability through preservation of a natural resource (e.g., reduction in uranium ore depletion), value from

  3. Advanced fusion MHD power conversion using the CFAR (compact fusion advanced Rankine) cycle concept

    SciTech Connect

    Hoffman, M.A.; Campbell, R.; Logan, B.G.; Lawrence Livermore National Lab., CA )

    1988-10-01

    The CFAR (compact fusion advanced Rankine) cycle concept for a tokamak reactor involves the use of a high-temperature Rankine cycle in combination with microwave superheaters and nonequilibrium MHD disk generators to obtain a compact, low-capital-cost power conversion system which fits almost entirely within the reactor vault. The significant savings in the balance-of-plant costs are expected to result in much lower costs of electricity than previous concepts. This paper describes the unique features of the CFAR cycle and a high- temperature blanket designed to take advantage of it as well as the predicted performance of the MHD disk generators using mercury seeded with cesium. 40 refs., 8 figs., 3 tabs.

  4. Discovery of Cycle-to-cycle Modulated Spectral Line Variability and Velocity Gradients in Long-period Cepheids

    NASA Astrophysics Data System (ADS)

    Anderson, Richard I.

    2016-08-01

    This work reports the discovery of cycle-to-cycle modulated spectral line and atmospheric velocity gradient variability in long-period Cepheids based on 925 high-resolution optical spectra of ℓ Carinae (P ˜ 35.5 d) recorded during three heavy duty-cycle monitoring campaigns (in 2014, 2015, and 2016). Spectral line variability is investigated via cross-correlation functions (CCFs) computed using three sets of spectral lines (weak, solar, strong). A metallic line velocity gradient, δvr(t), is computed as the difference between weak and strong-line RVs. CCF shape indicators BIS (asymmetry), FWHM, and depth all exhibit clear phase-dependent variability patterns that differ from one pulsation cycle to the next. Weak-line CCFs exhibit these effects more clearly than strong-line CCFs. BIS exhibits the most peculiar modulated variability and can be used to identify the presence of cycle-to-cycle modulated line profile variations. δvr(t) clearly exhibits cycle-to-cycle differences that correlate very closely with modulated BIS variability, suggesting perturbations of the atmospheric velocity field as the cause for modulated spectral line variability. These perturbations are most significant during contraction and are not in phase with the pulsation, transmitting information between consecutive pulsation cycles. This work shows RV curve modulation to be a consequence of atmospheric velocity gradient perturbations. Possible origins of these perturbations and their impact on Cepheid RV measurements as well as the projection factor used in Baade-Wesselink-type distance determinations are discussed.

  5. A thermionic topping cycle for advanced gas turbines

    SciTech Connect

    Paramonov, D.V.; Carelli, M.D.

    1998-07-01

    Thermionic energy converters (TICs) operate at high temperatures (1300--2300 K) and appear to be attractive for topping cycle (TC) applications of terrestrial fossil power plants where such high temperatures exist in combustion chambers. Thermionic TCs had been considered earlier for various types of gas and steam turbine power plants and cogeneration plants. The idea of the thermionic TC is follows: hot gases in the combustion chamber heat the TIC emitters (typically up to approximately 1600--2000 K), and collectors are cooled (approximately 900--1000 K) with air which is returned into the combustion chamber. Work performed in the early 80's under the DOE thermionic technology program had demonstrated that the use of thermionic TC on a GT might increase the overall efficiency and power output by several percentage points with an incremental efficiency of 70--88 %. In this paper the feasibility of increasing conversion efficiency of advanced GT plants (particularly Westinghouse 501ATS) using state-of-the-art and advanced thermionic technology is assessed. Four TIC types were considered in application to the GT TC. They include: conventional Cs ignited mode TIC; TIC with oxygenated electrodes; high temperature Cs-Ba TIC operating in Knudsen mode, and microgap TIC. The Westinghouse 501ATS was used as the basis for the TC analysis.

  6. Advanced continuously variable transmissions for electric and hybrid vehicles

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.

    1980-01-01

    A brief survey of past and present continuously variable transmissions (CVT) which are potentially suitable for application with electric and hybrid vehicles is presented. Discussion of general transmission requirements and benefits attainable with a CVT for electric vehicle use is given. The arrangement and function of several specific CVT concepts are cited along with their current development status. Lastly, the results of preliminary design studies conducted under a NASA contract for DOE on four CVT concepts for use in advanced electric vehicles are reviewed.

  7. The Adoption of Advanced Fuel Cycle Technology Under a Single Repository Policy

    SciTech Connect

    Paul Wilson

    2009-11-02

    Develops the tools to investiage the hypothesis that the savings in repository space associated with the implementation of advanced nuclear fuel cycles can result in sufficient cost savings to offset the higher costs of those fuel cycles.

  8. Sensitivity of Amazonian TOA flux diurnal cycle composite monthly variability to choice of reanalysis

    NASA Astrophysics Data System (ADS)

    Dodson, J. Brant; Taylor, Patrick C.

    2016-05-01

    Amazonian deep convection experiences a strong diurnal cycle driven by the cycle in surface sensible heat flux, which contributes to a significant diurnal cycle in the top of the atmosphere (TOA) radiative flux. Even when accounting for seasonal variability, the TOA flux diurnal cycle varies significantly on the monthly timescale. Previous work shows evidence supporting a connection between variability in the convective and radiative cycles, likely modulated by variability in monthly atmospheric state (e.g., convective instability). The hypothesized relationships are further investigated with regression analysis of the radiative diurnal cycle and atmospheric state using additional meteorological variables representing convective instability and upper tropospheric humidity. The results are recalculated with three different reanalyses to test the reliability of the results. The radiative diurnal cycle sensitivity to upper tropospheric humidity is about equal in magnitude to that of convective instability. In addition, the results are recalculated with the data subdivided into the wet and dry seasons. Overall, clear-sky radiative effects have a dominant role in radiative diurnal cycle variability during the dry season. Because of this, even in a convectively active region, the clear-sky radiative effects must be accounted for in order to fully explain the monthly variability in diurnal cycle. Finally, while there is general agreement between the different reanalysis-based results when examining the full data time domain (without regard to time of year), there are significant disagreements when the data are divided into wet and dry seasons. The questionable reliability of reanalysis data is a major limitation.

  9. On-Going Comparison of Advanced Fuel Cycle Options

    SciTech Connect

    Steven J. Piet; Ralph G. Bennett; Brent W. Dixon; J. Stephen Herring; David E. Shropshire; Mark Roth; J. D. Smith; Robert Hill; James Laidler; Kemal Pasamehmetoglu

    2004-10-01

    The Advanced Fuel Cycle Initiative (AFCI) program is addressing key issues associated with critical national needs. This paper compares the major options with these major “outcome” objectives - waste geological repository capacity and cost, energy security and sustainability, proliferation resistance, fuel cycle economics, and safety as well as “process” objectives associated with readiness to proceed and adaptability and robustness in the face of uncertainties. Working together, separation, transmutation, and fuel technologies provide complete energy systems that can improve waste management compared to the current “once-through/no separation” approach. Future work will further increase confidence in potential solutions, optimize solutions for the mixtures of objectives, and develop attractive development and deployment paths for selected options. This will allow the nation to address nearer-term issues such as avoiding the need for additional geological repositories while making nuclear energy a more sustainable energy option for the long-term. While the Generation IV Initiative is exploring multiple reactor options for future nuclear energy for both electricity generation and additional applications, the AFCI is assessing fuel cycles options for either a continuation or expansion of nuclear energy in the United States. This report compares strategies and technology options for managing the associated spent fuel. There are four major potential strategies, as follows: · The current U.S. strategy is once through: standard nuclear power plants, standard fuel burnup, direct geological disposal of spent fuel. Variants include higher burnup fuels in water-cooled power plants, once-through gas-cooled power plants, and separation (without recycling) of spent fuel to reduce the number and cost of geological waste packages. · The second strategy is thermal recycle, recycling some fuel components in thermal reactors. This strategy extends the useful life of

  10. Variable cycle stirling engine and gas leakage control system therefor

    SciTech Connect

    Otters, J.

    1984-12-25

    An improved thermal engine of the type having a displacer body movable between the hot end and the cold end of a chamber for subjecting a fluid within that chamber to a thermodynamic cycle and having a work piston driven by the fluid for deriving a useful work output. The work piston pumps a hydraulic fluid and a hydraulic control valve is connected in line with the hydraulic output conduit such that the flow of hydraulic fluid may be restricted to any desired degree or stopped altogether. The work piston can therefore be controlled by means of a controller device independently from the movement of the displacer such that a variety of engine cycles can be obtained for optimum engine efficiency under varying load conditions. While a Stirling engine cycle is particularly contemplated, other engine cycles may be obtained by controlling the movement of the displacer and work pistons. Also disclosed are a working gas recovery system for controlling leakage of working gas from the displacer chamber, and a compound work piston arrangement for preventing leakage of hydraulic fluid around the work piston into the displacer chamber.

  11. [Research advances in soil nitrogen cycling models and their simulation].

    PubMed

    Tang, Guoyong; Huang, Daoyou; Tong, Chengli; Zhang, Wenju; Wu, Jinshui

    2005-11-01

    Nitrogen is one of the necessary nutrients for plant, and also a primary element leading to environmental pollution. Many researches have been concerned about the contribution of agricultural activities to environmental pollution by nitrogenous compounds, and the focus is how to simulate soil nitrogen cycling processes correctly. In this paper, the primary soil nitrogen cycling processes were reviewed in brief, with 13 cycling models and 6 simulated cycling processes introduced, and the parameterization of models discussed. PMID:16471369

  12. Generic Repository Concepts and Thermal Analysis for Advanced Fuel Cycles

    SciTech Connect

    Hardin, Ernest; Blink, James; Carter, Joe; Massimiliano, Fratoni; Greenberg, Harris; Howard, Rob L

    2011-01-01

    The current posture of the used nuclear fuel management program in the U.S. following termination of the Yucca Mountain Project, is to pursue research and development (R&D) of generic (i.e., non-site specific) technologies for storage, transportation and disposal. Disposal R&D is directed toward understanding and demonstrating the performance of reference geologic disposal concepts selected to represent the current state-of-the-art in geologic disposal. One of the principal constraints on waste packaging and emplacement in a geologic repository is management of the waste-generated heat. This paper describes the selection of reference disposal concepts, and thermal management strategies for waste from advanced fuel cycles. A geologic disposal concept for spent nuclear fuel (SNF) or high-level waste (HLW) consists of three components: waste inventory, geologic setting, and concept of operations. A set of reference geologic disposal concepts has been developed by the U.S. Department of Energy (DOE) Used Fuel Disposition Campaign, for crystalline rock, clay/shale, bedded salt, and deep borehole (crystalline basement) geologic settings. We performed thermal analysis of these concepts using waste inventory cases representing a range of advanced fuel cycles. Concepts of operation consisting of emplacement mode, repository layout, and engineered barrier descriptions, were selected based on international progress and previous experience in the U.S. repository program. All of the disposal concepts selected for this study use enclosed emplacement modes, whereby waste packages are in direct contact with encapsulating engineered or natural materials. The encapsulating materials (typically clay-based or rock salt) have low intrinsic permeability and plastic rheology that closes voids so that low permeability is maintained. Uniformly low permeability also contributes to chemically reducing conditions common in soft clay, shale, and salt formations. Enclosed modes are associated

  13. Cenozoic carbon cycle imbalances and a variable weathering feedback

    NASA Astrophysics Data System (ADS)

    Caves, Jeremy K.; Jost, Adam B.; Lau, Kimberly V.; Maher, Kate

    2016-09-01

    The long-term stability of Earth's climate and the recovery of the ocean-atmosphere system after carbon cycle perturbations are often attributed to a stabilizing negative feedback between silicate weathering and climate. However, evidence for the operation of this feedback over million-year timescales and in response to tectonic and long-term climatic change remains scarce. For example, the past 50 million years of the Cenozoic Era are characterized by long-term cooling and declining atmospheric CO2 (pCO2). During this interval, constant or decreasing carbon fluxes from the solid Earth to the atmosphere suggest that stable or decreasing weathering fluxes are needed to balance the carbon cycle. In contrast, marine isotopic proxies of weathering (i.e., 87Sr/86Sr, δ7 Li , and 187Os/188Os) are interpreted to reflect increasing weathering fluxes. Here, we evaluate the existence of a negative feedback by reconstructing the imbalance in the carbon cycle during the Cenozoic using the surface inventories of carbon and alkalinity. Only a sustained 0.25-0.5% increase in silicate weathering is necessary to explain the long-term decline in pCO2 over the Cenozoic. We propose that the long-term decrease in pCO2 is due to an increase in the strength of the silicate weathering feedback (i.e., the constant of proportionality between the silicate weathering flux and climate), rather than an increase in the weathering flux. This increase in the feedback strength, which mirrors the marine isotope proxies, occurs as transient, <1 million year increases in the weathering flux, which remove CO2. As runoff and temperature decline in response, the integrated weathering flux over >1 million year timescales remains invariant to match the long-term inputs of carbon. Over the Cenozoic, this results in stable long-term weathering fluxes even as pCO2 decreases. We attribute increasing feedback strength to a change in the type and reactivity of rock in the weathering zone, which collectively has

  14. Orbit transfer vehicle advanced expander cycle engine point design study. Volume 2: Study results

    NASA Technical Reports Server (NTRS)

    Diem, H. G.

    1980-01-01

    The design characteristics of the baseline engine configuration of the advanced expander cycle engine are described. Several aspects of engine optimization are considered which directly impact the design of the baseline thrust chamber. Four major areas of the power cycle optimization are emphasized: main turbine arrangement; cycle engine source; high pressure pump design; and boost pump drive.

  15. Solar Cycle Variability in New Merge Satellite Ozone Datasets

    NASA Astrophysics Data System (ADS)

    Kuchar, A.; Pisoft, P.

    2014-12-01

    Studies using coupled chemistry climate model simulations of the solar cycle in the ozone field reveal agreement with the observed "double-peaked" ozone anomaly in the original satellite observations represented by SBUV(/2), HALOE and SAGE datasets. The motivation of our analysis is to examine whether the solar signal in the last generation of reanalyzed datasets (i.e. MERRA and ERA-INTERIM) is consistent with the observed double-peaked ozone anomaly extracted from satellite measurements. Since an analysis of the solar cycle response requires long-term and temporal homogeneous time series of the ozone profile and no single satellite instrument has covered the entire period since 1984, satellite measurements in our study are represented by new merged satellite ozone datasets, i.e. GOZCARDS, SBUV MOD and SWOOSH datasets. The results of the presented study are based on the attribution analysis using multiple nonlinear techniques besides traditional linear approach based on the multiple linear models. The study results are supplemented by a frequency analysis using the pseudo-2D wavelet transform algorithms.

  16. Rapid-cycling synchrotron with variable momentum compaction

    SciTech Connect

    Alexahin, Y.; Summers, D.J.; /Mississippi U.

    2010-05-01

    There are conflicting requirements on the value of the momentum compaction factor during energy ramping in a synchrotron: at low energies it should be positive and sufficiently large to make the slippage factor small so that it is possible to work closer to the RF voltage crest and ensure sufficient RF bucket area, whereas at higher energies it should be small or negative to avoid transition crossing. In the present report we propose a lattice with a variable momentum compaction factor and consider the possibility of using it in a high repetition rate proton driver for a muon collider and neutrino factory.

  17. On-Going Comparison of Advanced Fuel Cycle Options

    SciTech Connect

    Piet, S.J.; Bennett, R.G.; Dixon, B.W.; Herring, J.S.; Shropshire, D.E.; Roth, M.; Smith, J.D.; Finck, P.; Hill, R.; Laidler, J.; Pasamehmetoglu, K.

    2004-10-03

    This paper summarizes the current comprehensive comparison of four major fuel cycle strategies: once-through, thermal recycle, thermal+fast recycle, fast recycle. It then proceeds to summarize comparison of the major technology options for the key elements of the fuel cycle that can implement each of the four strategies - separation processing, transmutation reactors, and fuels.

  18. Advanced nuclear fuel cycles - Main challenges and strategic choices

    SciTech Connect

    Le Biez, V.; Machiels, A.; Sowder, A.

    2013-07-01

    A graphical conceptual model of the uranium fuel cycles has been developed to capture the present, anticipated, and potential (future) nuclear fuel cycle elements. The once-through cycle and plutonium recycle in fast reactors represent two basic approaches that bound classical options for nuclear fuel cycles. Chief among these other options are mono-recycling of plutonium in thermal reactors and recycling of minor actinides in fast reactors. Mono-recycling of plutonium in thermal reactors offers modest savings in natural uranium, provides an alternative approach for present-day interim management of used fuel, and offers a potential bridging technology to development and deployment of future fuel cycles. In addition to breeder reactors' obvious fuel sustainability advantages, recycling of minor actinides in fast reactors offers an attractive concept for long-term management of the wastes, but its ultimate value is uncertain in view of the added complexity in doing so,. Ultimately, there are no simple choices for nuclear fuel cycle options, as the selection of a fuel cycle option must reflect strategic criteria and priorities that vary with national policy and market perspectives. For example, fuel cycle decision-making driven primarily by national strategic interests will likely favor energy security or proliferation resistance issues, whereas decisions driven primarily by commercial or market influences will focus on economic competitiveness.

  19. High-Level Functional and Operational Requirements for the Advanced Fuel Cycle Facilty

    SciTech Connect

    Charles Park

    2006-12-01

    High-Level Functional & Operational Requirements for the AFCF -This document describes the principal functional and operational requirements for the proposed Advanced Fuel Cycle Facility (AFCF). The AFCF is intended to be the world's foremost facility for nuclear fuel cycle research, technology development, and demonstration. The facility will also support the near-term mission to develop and demonstrate technology in support of fuel cycle needs identified by industry, and the long-term mission to retain and retain U.S. leadership in fuel cycle operations. The AFCF is essential to demonstrate a more proliferation-resistant fuel cycle and make long-term improvements in fuel cycle effectiveness, performance and economy.

  20. Low emission advanced power cycle. Final CRADA report.

    SciTech Connect

    Tentner, A.; Nuclear Engineering Division

    2010-07-13

    Today's gas turbines are based on the Brayton Cycle in which heat is added to the working fluid at constant pressure. An alternate approach, the Humphrey cycle, provides a higher theoretical thermal efficiency by adding heat at constant, or near constant volume. A few practical examples of such engines appeared in the mid 1900's, but they were largely superseded by the Brayton engine. Although the conventional gas turbine has been developed to a high level of efficiency and reliability, significant improvements in performance are becoming increasingly costly to obtain. Efficiencies of compressors, turbines and combustors are approaching theoretical limits. Cooling and materials technologies continue to improve but higher cycle temperatures may be limited by NOx emissions. While heat exchangers, intercoolers and other features improve cycle efficiency they add significantly to the cost, weight and volume of the basic engine and for flight applications may always be impractical. For these reasons there has been renewed interest in recent years in the constant volume Humphrey cycle focusing mainly on pulsing systems in which heat is added by a rapid series of detonations. Variations on this basic scheme are being evaluated for aircraft propulsions systems. General Electric has established a joint program with several Russian organizations to explore devices based on pressure rise combustion cycle and to make fundamental measurements of detonation properties of mixtures of hydrocarbon fuels and air.

  1. Computational Fluid Dynamics Modeling of a Supersonic Nozzle and Integration into a Variable Cycle Engine Model

    NASA Technical Reports Server (NTRS)

    Connolly, Joseph W.; Friedlander, David; Kopasakis, George

    2015-01-01

    This paper covers the development of an integrated nonlinear dynamic simulation for a variable cycle turbofan engine and nozzle that can be integrated with an overall vehicle Aero-Propulso-Servo-Elastic (APSE) model. A previously developed variable cycle turbofan engine model is used for this study and is enhanced here to include variable guide vanes allowing for operation across the supersonic flight regime. The primary focus of this study is to improve the fidelity of the model's thrust response by replacing the simple choked flow equation convergent-divergent nozzle model with a MacCormack method based quasi-1D model. The dynamic response of the nozzle model using the MacCormack method is verified by comparing it against a model of the nozzle using the conservation element/solution element method. A methodology is also presented for the integration of the MacCormack nozzle model with the variable cycle engine.

  2. Computational Fluid Dynamics Modeling of a Supersonic Nozzle and Integration into a Variable Cycle Engine Model

    NASA Technical Reports Server (NTRS)

    Connolly, Joseph W.; Friedlander, David; Kopasakis, George

    2014-01-01

    This paper covers the development of an integrated nonlinear dynamic simulation for a variable cycle turbofan engine and nozzle that can be integrated with an overall vehicle Aero-Propulso-Servo-Elastic (APSE) model. A previously developed variable cycle turbofan engine model is used for this study and is enhanced here to include variable guide vanes allowing for operation across the supersonic flight regime. The primary focus of this study is to improve the fidelity of the model's thrust response by replacing the simple choked flow equation convergent-divergent nozzle model with a MacCormack method based quasi-1D model. The dynamic response of the nozzle model using the MacCormack method is verified by comparing it against a model of the nozzle using the conservation element/solution element method. A methodology is also presented for the integration of the MacCormack nozzle model with the variable cycle engine.

  3. Life-cycle modification in open oceans accounts for genome variability in a cosmopolitan phytoplankton.

    PubMed

    von Dassow, Peter; John, Uwe; Ogata, Hiroyuki; Probert, Ian; Bendif, El Mahdi; Kegel, Jessica U; Audic, Stéphane; Wincker, Patrick; Da Silva, Corinne; Claverie, Jean-Michel; Doney, Scott; Glover, David M; Flores, Daniella Mella; Herrera, Yeritza; Lescot, Magali; Garet-Delmas, Marie-José; de Vargas, Colomban

    2015-06-01

    Emiliania huxleyi is the most abundant calcifying plankton in modern oceans with substantial intraspecific genome variability and a biphasic life cycle involving sexual alternation between calcified 2N and flagellated 1N cells. We show that high genome content variability in Emiliania relates to erosion of 1N-specific genes and loss of the ability to form flagellated cells. Analysis of 185 E. huxleyi strains isolated from world oceans suggests that loss of flagella occurred independently in lineages inhabiting oligotrophic open oceans over short evolutionary timescales. This environmentally linked physiogenomic change suggests life cycling is not advantageous in very large/diluted populations experiencing low biotic pressure and low ecological variability. Gene loss did not appear to reflect pressure for genome streamlining in oligotrophic oceans as previously observed in picoplankton. Life-cycle modifications might be common in plankton and cause major functional variability to be hidden from traditional taxonomic or molecular markers. PMID:25461969

  4. Life-cycle modification in open oceans accounts for genome variability in a cosmopolitan phytoplankton

    PubMed Central

    von Dassow, Peter; John, Uwe; Ogata, Hiroyuki; Probert, Ian; Bendif, El Mahdi; Kegel, Jessica U; Audic, Stéphane; Wincker, Patrick; Da Silva, Corinne; Claverie, Jean-Michel; Doney, Scott; Glover, David M; Flores, Daniella Mella; Herrera, Yeritza; Lescot, Magali; Garet-Delmas, Marie-José; de Vargas, Colomban

    2015-01-01

    Emiliania huxleyi is the most abundant calcifying plankton in modern oceans with substantial intraspecific genome variability and a biphasic life cycle involving sexual alternation between calcified 2N and flagellated 1N cells. We show that high genome content variability in Emiliania relates to erosion of 1N-specific genes and loss of the ability to form flagellated cells. Analysis of 185 E. huxleyi strains isolated from world oceans suggests that loss of flagella occurred independently in lineages inhabiting oligotrophic open oceans over short evolutionary timescales. This environmentally linked physiogenomic change suggests life cycling is not advantageous in very large/diluted populations experiencing low biotic pressure and low ecological variability. Gene loss did not appear to reflect pressure for genome streamlining in oligotrophic oceans as previously observed in picoplankton. Life-cycle modifications might be common in plankton and cause major functional variability to be hidden from traditional taxonomic or molecular markers. PMID:25461969

  5. Indonesian Throughflow variability over the last glacial cycle (Invited)

    NASA Astrophysics Data System (ADS)

    Holbourn, A. E.; Kuhnt, W.; Regenberg, M.; Xu, J.; Hendrizan, M.; Schröder, J.

    2013-12-01

    The transfer of surface and intermediate waters from the Pacific Ocean to the Indian Ocean through the Indonesian archipelago (Indonesian Throughflow: ITF) strongly influences the heat and freshwater budgets of tropical water masses, in turn affecting global climate. Key areas for monitoring past ITF variations through this critical gateway are the narrow passages through the Makassar Strait and Flores Sea and the main outflow area within the Timor Sea. Here, we integrate high-resolution sea surface temperature and salinity reconstructions (based on paired planktic foraminiferal Mg/Ca and δ18O) with X-ray fluorescence runoff data and benthic isotopes from marine sediment cores retrieved in these regions during several cruises with RV'Sonne' and RV'Marion Dufresne'. Our results show that high latitude climate variability strongly influenced ITF intensity on millennial to centennial timescales as well as on longer glacial-interglacial timescales. Marked declines in ITF strength occurred during Heinrich events and the Younger Dryas, most likely related to slowdown of the global thermohaline circulation during colder northern hemisphere climate spells, when deep water production decreased and the deep ocean became more stratified. Additionally, the surface component of the ITF strongly reflects regional windstress and rainfall patterns, and thus the spatial extent and intensity of the tropical convection over the Indonesian archipelago. Our runoff and salinity estimates reveal that the development of the tropical convection was intricately linked to the latitudinal migration of the Inter Tropical Convergence Zone (ITCZ). In particular, our data show that the Australian monsoon intensified during the major deglacial atmospheric CO2 rise through the Younger Dryas and earliest Holocene (12.9-10 ka). This massive intensification of the Australian monsoon coincided with a southward shift of the ITCZ, linked to southern hemisphere warming and enhanced greenhouse forcing

  6. Advances in open-cycle solid desiccant cooling

    SciTech Connect

    Penney, T R; Maclaine-cross, I

    1985-05-01

    Of the solar cooling options available open cycle solid desiccant cooling looks very promising. A brief review of the experimental and analytical efforts to date shows that within the last 10 years thermal performance has doubled. Research centers have been developed to explore new materials and geometry options and to improve and validate mathematical models that can be used by design engineers to develop new product lines. Typical results from the Solar Energy Research Institute's (SERI) Desiccant Cooling Research Program are shown. Innovative ideas for new cycles and spinoff benefits provide incentives to continue research in this promising field.

  7. On multi-timescale variability of temperature in China in modulated annual cycle reference frame

    NASA Astrophysics Data System (ADS)

    Qian, Cheng; Wu, Zhaohua; Fu, Congbin; Zhou, Tianjun

    2010-09-01

    The traditional anomaly (TA) reference frame and its corresponding anomaly for a given data span changes with the extension of data length. In this study, the modulated annual cycle (MAC), instead of the widely used climatological mean annual cycle, is used as an alternative reference frame for computing climate anomalies to study the multi-timescale variability of surface air temperature (SAT) in China based on homogenized daily data from 1952 to 2004. The Ensemble Empirical Mode Decomposition (EEMD) method is used to separate daily SAT into a high frequency component, a MAC component, an interannual component, and a decadal-to-trend component. The results show that the EEMD method can reflect historical events reasonably well, indicating its adaptive and temporally local characteristics. It is shown that MAC is a temporally local reference frame and will not be altered over a particular time span by an extension of data length, thereby making it easier for physical interpretation. In the MAC reference frame, the low frequency component is found more suitable for studying the interannual to longer timescale variability (ILV) than a 13-month window running mean, which does not exclude the annual cycle. It is also better than other traditional versions (annual or summer or winter mean) of ILV, which contains a portion of the annual cycle. The analysis reveals that the variability of the annual cycle could be as large as the magnitude of interannual variability. The possible physical causes of different timescale variability of SAT in China are further discussed.

  8. Weekly cycles in precipitation and other meteorological variables in a polluted region of Europe

    NASA Astrophysics Data System (ADS)

    Stjern, C. W.

    2011-05-01

    Weekly cycles in aerosol concentration and corresponding cycles in precipitation have been reported over Europe, but results are conflicting. To obtain a large potential effect of aerosols on precipitation the focus will here be on a highly polluted region on the borders between Germany, Poland and the Czech Republic. Meteorological parameters from 30 surface stations in a mix of urban, rural and remote locations were analyzed for the time period 1983-2008, using three different tests: the Kruskal-Wallis test, a spectral analysis and a comparison of the regular 7-day week to constructed 6- and 8-day weeks. A clear and statistically significant weekly cycle will be expected to pass all three tests. Precipitation amount as well as meteorological variables associated with convective conditions, such as the frequency of heavy precipitation events and observations of rain showers, showed two-peak weekly cycles with maxima on Tuesdays and during weekends. The amplitudes of the weekly cycles were in many cases larger for the heavily polluted 1983-1987 period than for the cleaner 2004-2008 period, but were equally often largest in the cleaner period. Moreover, of all the variables, periods and seasons investigated, the weekly cycles were statistically significant only for summertime values of light precipitation frequency and cloud amount, and only by one of the three tests applied (the Kruskal-Wallis test). Conclusively, clear weekly cycles in meteorological variables were not found in this polluted region of Europe.

  9. Acoustic and aerodynamic performance investigation of inverted velocity profile coannular plug nozzles. [variable cycle engines

    NASA Technical Reports Server (NTRS)

    Knott, P. R.; Blozy, J. T.; Staid, P. S.

    1981-01-01

    The results of model scale parametric static and wind tunnel aerodynamic performance tests on unsuppressed coannular plug nozzle configurations with inverted velocity profile are discussed. The nozzle configurations are high-radius-ratio coannular plug nozzles applicable to dual-stream exhaust systems typical of a variable cycle engine for Advanced Supersonic Transport application. In all, seven acoustic models and eight aerodynamic performance models were tested. The nozzle geometric variables included outer stream radius ratio, inner stream to outer stream ratio, and inner stream plug shape. When compared to a conical nozzle at the same specific thrust, the results of the static acoustic tests with the coannular nozzles showed noise reductions of up to 7 PNdB. Extensive data analysis showed that the overall acoustic results can be well correlated using the mixed stream velocity and the mixed stream density. Results also showed that suppression levels are geometry and flow regulation dependent with the outer stream radius ratio, inner stream-to-outer stream velocity ratio and inner stream velocity ratio and inner stream plug shape, as the primary suppression parameters. In addition, high-radius ratio coannular plug nozzles were found to yield shock associated noise level reductions relative to a conical nozzle. The wind tunnel aerodynamic tests showed that static and simulated flight thrust coefficient at typical takeoff conditions are quite good - up to 0.98 at static conditions and 0.974 at a takeoff Mach number of 0.36. At low inner stream flow conditions significant thrust loss was observed. Using an inner stream conical plug resulted in 1% to 2% higher performance levels than nozzle geometries using a bent inner plug.

  10. Advanced Electrochemical Technologies for Hydrogen Production by Alternative Thermochemical Cycles

    SciTech Connect

    Lvov, Serguei; Chung, Mike; Fedkin, Mark; Lewis, Michele; Balashov, Victor; Chalkova, Elena; Akinfiev, Nikolay; Stork, Carol; Davis, Thomas; Gadala-Maria, Francis; Stanford, Thomas; Weidner, John; Law, Victor; Prindle, John

    2011-01-06

    Hydrogen fuel is a potentially major solution to the problem of climate change, as well as addressing urban air pollution issues. But a key future challenge for hydrogen as a clean energy carrier is a sustainable, low-cost method of producing it in large capacities. Most of the world's hydrogen is currently derived from fossil fuels through some type of reforming processes. Nuclear hydrogen production is an emerging and promising alternative to the reforming processes for carbon-free hydrogen production in the future. This report presents the main results of a research program carried out by a NERI Consortium, which consisted of Penn State University (PSU) (lead), University of South Carolina (USC), Tulane University (TU), and Argonne National Laboratory (ANL). Thermochemical water decomposition is an emerging technology for large-scale production of hydrogen. Typically using two or more intermediate compounds, a sequence of chemical and physical processes split water into hydrogen and oxygen, without releasing any pollutants externally to the atmosphere. These intermediate compounds are recycled internally within a closed loop. While previous studies have identified over 200 possible thermochemical cycles, only a few have progressed beyond theoretical calculations to working experimental demonstrations that establish scientific and practical feasibility of the thermochemical processes. The Cu-Cl cycle has a significant advantage over other cycles due to lower temperature requirements – around 530 °C and below. As a result, it can be eventually linked with the Generation IV thermal power stations. Advantages of the Cu-Cl cycle over others include lower operating temperatures, ability to utilize low-grade waste heat to improve energy efficiency, and potentially lower cost materials. Another significant advantage is a relatively low voltage required for the electrochemical step (thus low electricity input). Other advantages include common chemical agents and

  11. Orbit Transfer Vehicle (OTV) advanced expander cycle engine point design study. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The objective of the study was to generate the system design of a performance-optimized, advanced LOX/hydrogen expander cycle space engine. The engine requirements are summarized, and the development and operational experience with the expander cycle RL10 engine were reviewed. The engine development program is outlined.

  12. Advanced Low Temperature Geothermal Power Cycles (The ENTIV Organic Project) Final Report

    SciTech Connect

    Mugerwa, Michael

    2015-11-18

    Feasibility study of advanced low temperature thermal power cycles for the Entiv Organic Project. Study evaluates amonia-water mixed working fluid energy conversion processes developed and licensed under Kalex in comparison with Kalina cycles. Both cycles are developed using low temperature thermal resource from the Lower Klamath Lake Geothermal Area. An economic feasibility evaluation was conducted for a pilot plant which was deemed unfeasible by the Project Sponsor (Entiv).

  13. Gas Foil Bearing Technology Advancements for Closed Brayton Cycle Turbines

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.; Bruckner, Robert J.; DellaCorte, Christopher; Radil, Kevin C.

    2007-01-01

    Closed Brayton Cycle (CBC) turbine systems are under consideration for future space electric power generation. CBC turbines convert thermal energy from a nuclear reactor, or other heat source, to electrical power using a closed-loop cycle. The operating fluid in the closed-loop is commonly a high pressure inert gas mixture that cannot tolerate contamination. One source of potential contamination in a system such as this is the lubricant used in the turbomachine bearings. Gas Foil Bearings (GFB) represent a bearing technology that eliminates the possibility of contamination by using the working fluid as the lubricant. Thus, foil bearings are well suited to application in space power CBC turbine systems. NASA Glenn Research Center is actively researching GFB technology for use in these CBC power turbines. A power loss model has been developed, and the effects of a very high ambient pressure, start-up torque, and misalignment, have been observed and are reported here.

  14. Solar Cycle Induced Variability in Middle Atmospheric HOx — Abundances and Partitioning

    NASA Astrophysics Data System (ADS)

    Wang, S.; Millan Valle, L. F.; Li, K. F.; Sander, S. P.; Yung, Y. L.; Livesey, N. J.; Santee, M. L.; Liang, M. C.

    2014-12-01

    Solar UV irradiance variability during the 11-year solar cycle has strong impacts on Earth's atmospheric composition and climate. The odd hydrogen species HOx (primarily OH and HO2), which plays a key role in controlling middle atmospheric ozone, are expected to show distinct variability following the solar cycle. Previous investigations based on total OH abundances from long-term ground-based observation and 5.5 year Aura/Microwave Limb Sounder (MLS) OH data and model calculations suggest that the HOx solar cycle variability may dominate the ozone solar cycle variability above 40 km. In the present study, we expand the investigation to both HO2 and OH, as well as the partitioning between them, which is important in the catalytic HOx cycle. With the newly developed MLS offline HO2 product that has significantly improved data quality and better vertical and diurnal coverage, we examine the vertical and latitudinal distribution of the solar cycle signals in HO2 (~10 year data) and compare it with OH. Model simulations using the Caltech/JPL 1-D photochemical model are used to understand the detailed mechanisms controlling the variability in HOx abundances and partitioning. The results of using different solar spectral irradiance (SSI) variabilities in models and the comparison with observations will be discussed. In addition, while the continuous MLS OH data record is only 5.5 year, the MLS THz sub-system was turned back on for a 30-day OH measurement in every August since 2011. Using the most recent version of MLS retrieval software (v4.1x, to be released), some first OH data for selected months will be presented, suggesting reliable quality of the "THz restart" observations and making it promising to combine such OH data with earlier OH data to build a longer-term record.

  15. AeroPropulsoServoElasticity: Dynamic Modeling of the Variable Cycle Propulsion System

    NASA Technical Reports Server (NTRS)

    Kopasakis, George

    2012-01-01

    This presentation was made at the 2012 Fundamental Aeronautics Program Technical Conference and it covers research work for the Dynamic Modeling of the Variable cycle Propulsion System that was done under the Supersonics Project, in the area of AeroPropulsoServoElasticity. The presentation covers the objective for the propulsion system dynamic modeling work, followed by the work that has been done so far to model the variable Cycle Engine, modeling of the inlet, the nozzle, the modeling that has been done to model the affects of flow distortion, and finally presenting some concluding remarks and future plans.

  16. The seasonal cycle and variability of sea level in the South China Sea

    NASA Astrophysics Data System (ADS)

    Amiruddin, A. M.; Haigh, I. D.; Tsimplis, M. N.; Calafat, F. M.; Dangendorf, S.

    2015-08-01

    The spatial and temporal characteristics of the seasonal sea level cycle in the South China Sea (SCS) and its forcing mechanisms are investigated using tide gauge records and satellite altimetry observations along with steric and meteorological data. The coastal mean annual amplitude of the seasonal cycle varies between zero and 24 cm, reaching a maximum between July and January. The maximum mean semiannual amplitude is 7 cm, peaking between March and June. Along the coast, the seasonal cycle accounts for up to 92% of the mean monthly sea level variability. Atmospheric pressure explains a significant portion of the seasonal cycle with dominant annual signals in the northern SCS, the Gulf of Thailand and the north-western Philippines Sea. The wind forcing is dominant on the shelf areas of the SCS and the Gulf of Thailand where a simple barotropic model forced by the local wind shows annual amplitudes of up to 27 cm. In the deep basin of the SCS, the Philippines Sea and the shallow Malacca Strait, the steric component is the major contributor with the maximum annual amplitudes reaching 15 cm. Significant variability in the seasonal cycle is found on a year-to-year basis. The annual and semiannual amplitudes vary by up to 63% and 45% of the maximum values, 15 cm and 11 cm, respectively. On average, stepwise regression analysis of contribution of different forcing factors accounts for 66% of the temporal variability of the annual cycle. The zonal wind was found to exert considerable influence in the Malacca Strait.

  17. Effects of bolus size and hardness on within-subject variability of chewing cycle kinematics.

    PubMed

    Wintergerst, Ana M; Throckmorton, Gaylord S; Buschang, Peter H

    2008-04-01

    This study analysed how bolus hardness and size affect within-subject variability of chewing cycle kinematics. Two independent prospective studies were performed; both tracked chin movements using an optoelectronic recording system. Computer programs identified each subject's ten most representative cycles, and multilevel modelling procedures were used to estimate variances. One study evaluated 38 subjects who chewed 1, 2, 4 or 8 g of gum presented in random order. The second study evaluated 26 subjects who chewed approximately 2.5 g of harder (670 g) or softer (440 g) gum, also presented in random order. In terms of bolus size, the 2g and 1g boluses produced the least and greatest relative within-subject variability, respectively; the largest differences were found for cycle duration and excursions. Within-subject variability when chewing the harder gum was consistently greater than when chewing the softer gum, except for lateral movement towards the balancing side. Because bolus hardness and bolus size influence within-subject variability differently, they must be taken into consideration when designing experiments to study masticatory kinematics. We conclude that a 2g bolus of soft gum should be used in studies of chewing cycle kinematics in order to reduce within-subject variability and increase statistical power. PMID:18093571

  18. Design study and performance analysis of a high-speed multistage variable-geometry fan for a variable cycle engine

    NASA Technical Reports Server (NTRS)

    Sullivan, T. J.; Parker, D. E.

    1979-01-01

    A design technology study was performed to identify a high speed, multistage, variable geometry fan configuration capable of achieving wide flow modulation with near optimum efficiency at the important operating condition. A parametric screening study of the front and rear block fans was conducted in which the influence of major fan design features on weight and efficiency was determined. Key design parameters were varied systematically to determine the fan configuration most suited for a double bypass, variable cycle engine. Two and three stage fans were considered for the front block. A single stage, core driven fan was studied for the rear block. Variable geometry concepts were evaluated to provide near optimum off design performance. A detailed aerodynamic design and a preliminary mechanical design were carried out for the selected fan configuration. Performance predictions were made for the front and rear block fans.

  19. Identification of essential Alphaproteobacterial genes reveals operational variability in conserved developmental and cell cycle systems

    PubMed Central

    Curtis, Patrick D.; Brun, Yves V.

    2014-01-01

    Summary The cell cycle of Caulobacter crescentus is controlled by a complex signaling network that coordinates events. Genome sequencing has revealed many C. crescentus cell cycle genes are conserved in other Alphaproteobacteria, but it is not clear to what extent their function is conserved. As many cell cycle regulatory genes are essential in C. crescentus, the essential genes of two Alphaproteobacteria, Agrobacterium tumefaciens (Rhizobiales) and Brevundimonas subvibrioides (Caulobacterales), were elucidated to identify changes in cell cycle protein function over different phylogenetic distances as demonstrated by changes in essentiality. The results show the majority of conserved essential genes are involved in critical cell cycle processes. Changes in component essentiality reflect major changes in lifestyle, such as divisome components in A. tumefaciens resulting from that organism’s different growth pattern. Larger variability of essentiality was observed in cell cycle regulators, suggesting regulatory mechanisms are more customizable than the processes they regulate. Examples include variability in the essentiality of divJ and divK spatial cell cycle regulators, and non-essentiality of the highly conserved and usually essential DNA methyltransferase CcrM. These results show that while essential cell functions are conserved across varying genetic distance, much of a given organism’s essential gene pool is specific to that organism. PMID:24975755

  20. Towards the understanding of cyclic variability in a spark ignited engine using multi-cycle LES

    SciTech Connect

    Vermorel, O.; Richard, S.; Colin, O.; Angelberger, C.; Benkenida, A.; Veynante, D.

    2009-08-15

    Large-Eddy Simulation (LES) has been used to analyze the occurrence and the causes of cycle-to-cycle combustion variations in a spark ignited four-valve single cylinder engine fueled with a homogeneous propane-air mixture. The combustion modeling combines an Eulerian model derived from the RANS AKTIM model that mimics the spark ignition and the Extended Coherent Flame Model (ECFM-LES) that describes the flame propagation. The motion of piston and valves is accounted for using an Arbitrary Eulerian Lagrangian (ALE) technique with body-fitted meshes. The computation covers nine consecutive complete four-stroke cycles following an initialization cycle. The obtained LES results are compared with experimental measurements. Although the number of computed cycles is fairly low, LES is shown to be able to reproduce both quantitatively and qualitatively the cyclic variability observed experimentally. The investigation of the possible causes of variability illustrates the unprecedented possibility LES offers for understanding cycle-to-cycle variations. (author)

  1. Orbital transfer vehicle advanced expander cycle engine point design study

    NASA Technical Reports Server (NTRS)

    Martinez, A.

    1979-01-01

    A detailed computer model of the expander cycle engine system steady-state operation was developed. Payload performance data for the expander cycle engine for 100K pounds and 65K pounds Space Shuttle missions were examined to establish peak payload thrusts. It was found that peak payload for the 100K pound gross weight single engine case occurred at nearly 15,000 pounds thrust for both engine mixture ratios of 6:1 and 7:1. Peak payload at engine mixture ratio of 6:1 was 4 percent greater than at 7:1 mixture ratio. The two engine configuration peak paYloads occurred at engine thrust below 7,500 pounds (extrapolated) and were lower than single engine payloads. For the 65K pound gross weight mission, peak payloads for the single engine configuration occurred at nearly 10,000 pounds for both mixture ratios. Mixture ratio of 7:1 payloads were 5 percent lower than 6:1 payloads. Two engine configuration payloads occurred at engine thrusts considerably below 10K pounds.

  2. EXPERIMENTAL AND THEORETICAL INVESTIGATIONS OF NEW POWER CYCLES AND ADVANCED FALLING FILM HEAT EXCHANGERS

    SciTech Connect

    Arsalan Razani; Kwang J. Kim

    2001-12-01

    The final report for the DOE/UNM grant number DE-FG26-98FT40148 discusses the accomplishments of both the theoretical analysis of advanced power cycles and experimental investigation of advanced falling film heat exchangers. This final report also includes the progress report for the third year (period of October 1, 2000 to September 30, 2001). Four new cycles were studied and two cycles were analyzed in detail based on the second law of thermodynamics. The first cycle uses a triple combined cycle, which consists of a topping cycle (Brayton/gas), an intermediate cycle (Rankine/steam), and a bottoming cycle (Rankine/ammonia). This cycle can produce high efficiency and reduces the irreversibility of the Heat Recovery Steam Generator (HRSC) of conventional combined power cycles. The effect of important system parameters on the irreversibility distribution of all components in the cycle under reasonable practical constraints was evaluated. The second cycle is a combined cycle, which consists of a topping cycle (Brayton/gas) and a bottoming cycle (Rankine/ammonia) with integrated compressor inlet air cooling. This innovative cycle can produce high power and efficiency. This cycle is also analyzed and optimized based on the second the second law to obtain the irreversibility distribution of all components in the cycle. The results of the studies have been published in peer reviewed journals and ASME conference proceeding. Experimental investigation of advanced falling film heat exchangers was conducted to find effective additives for steam condensation. Four additives have been selected and tested in a horizontal tube steam condensation facility. It has been observed that heat transfer additives have been shown to be an effective way to increase the efficiency of conventional tube bundle condenser heat exchangers. This increased condensation rate is due to the creation of a disturbance in the liquid condensate surround the film. The heat transfer through such a film has

  3. Variability in Cadence During Forced Cycling Predicts Motor Improvement in Individuals With Parkinson’s Disease

    PubMed Central

    Ridgel, Angela L.; Abdar, Hassan Mohammadi; Alberts, Jay L.; Discenzo, Fred M.; Loparo, Kenneth A.

    2014-01-01

    Variability in severity and progression of Parkinson’s disease symptoms makes it challenging to design therapy interventions that provide maximal benefit. Previous studies showed that forced cycling, at greater pedaling rates, results in greater improvements in motor function than voluntary cycling. The precise mechanism for differences in function following exercise is unknown. We examined the complexity of biomechanical and physiological features of forced and voluntary cycling and correlated these features to improvements in motor function as measured by the Unified Parkinson’s Disease Rating Scale (UPDRS). Heart rate, cadence, and power were analyzed using entropy signal processing techniques. Pattern variability in heart rate and power were greater in the voluntary group when compared to forced group. In contrast, variability in cadence was higher during forced cycling. UPDRS Motor III scores predicted from the pattern variability data were highly correlated to measured scores in the forced group. This study shows how time series analysis methods of biomechanical and physiological parameters of exercise can be used to predict improvements in motor function. This knowledge will be important in the development of optimal exercise-based rehabilitation programs for Parkinson’s disease. PMID:23144045

  4. Fabrication of functionally gradient nanocomposite coatings by plasma electrolytic oxidation based on variable duty cycle

    NASA Astrophysics Data System (ADS)

    Aliofkhazraei, M.; Rouhaghdam, A. Sabour

    2012-01-01

    Plasma electrolytic oxidation (PEO) was applied on the surface of commercially pure titanium substrates in a mixed aluminate-phosphate electrolyte in the presence of silicon nitride nanoparticles as suspension in the electrolyte in order to fabricate nanocomposite coatings. Pulsed current was applied based on variable duty cycle in order to synthesize functionally gradient coatings (FGC). Different rates of variable duty cycle (3, 1.5 and 1%/min), applied current densities (0.06-0.14 A/cm2) and concentrations of nanoparticles in the electrolyte (2, 4, 6, 8 and 10 g l-1) were investigated. The nanopowder and coated samples were analyzed by atomic force microscope, scanning electron microscope and transmission electron microscope. The influence of different rates of variable duty cycle (or treatment times) on the growth rate of nanocomposite coatings and their microhardness values was investigated. The experimental results revealed that the content of Si3N4 nanoparticulates in the layer increases with the increase of its concentration in the plasma electrolysis bath. Nanocomposite coatings fabricated with lower rate of variable duty cycle have higher microhardness with smoother microhardness profile.

  5. Grouped actinide separation in advanced nuclear fuel cycles

    SciTech Connect

    Glatz, J.P.; Malmbeck, R.; Ougier, M.; Soucek, P.; Murakamin, T.; Tsukada, T.; Koyama, T.

    2013-07-01

    Aiming at cleaner waste streams (containing only the short-lived fission products) a partitioning and transmutation (P-T) scheme can significantly reduce the quantities of long-lived radionuclides consigned to waste. Many issues and options are being discussed and studied at present in view of selecting the optimal route. The choice is between individual treatment of the relevant elements and a grouped treatment of all actinides together. In the European Collaborative Project ACSEPT (Actinide recycling by Separation and Transmutation), grouped separation options derived from an aqueous extraction or from a dry pyroprocessing route were extensively investigated. Successful demonstration tests for both systems have been carried out in the frame of this project. The aqueous process called GANEX (Grouped Actinide Extraction) is composed of 2 cycles, a first one to recover the major part of U followed by a co-extraction of Np, Pu, Am, and Cm altogether. The pyro-reprocessing primarily applicable to metallic fuels such as the U-Pu-Zr alloy originally developed by the Argonne National Laboratory (US) in the mid 1980s, has also been applied to the METAPHIX fuels containing up to 5% of minor actinides and 5% of lanthanides (e.g. U{sub 60}Pu{sub 20}-Zr{sub 10}Am{sub 2}Nd{sub 3.5}Y{sub 0.5}Ce{sub 0.5}Gd{sub 0.5}). A grouped actinide separation has been successfully carried out by electrorefining on solid Al cathodes. At present the recovery of the actinides from the alloy formed with Al upon electrodeposition is under investigation, because an efficient P-T cycle requires multiple re-fabrication and re-irradiation. (authors)

  6. Climatology and natural variability of the global hydrologic cycle in the GLA atmospheric general circulation model

    NASA Technical Reports Server (NTRS)

    Lau, K.-M.; Mehta, V. M.; Sud, Y. C.; Walker, G. K.

    1994-01-01

    Time average climatology and low-frequency variabilities of the global hydrologic cycle (GHC) in the Goddard Laboratory for Atmospheres (GLA) general circulation model (GCM) were investigated in the present work. A 730-day experiment was conducted with the GLA GCM forced by insolation, sea surface temperature, and ice-snow undergoing climatological annual cycles. Ifluences of interactive soil moisture on time average climatology and natural variability of the GHC were also investigated by conducting 365-day experiments with and without interactive soil moisture. Insolation, sea surface temperature, and ice-snow were fixed at their July levels in the latter two experiments. Results show that the model's time average hydrologic cycle variables for July in all three experiments agree reasonably well with observations. Except in the case of precipitable water, the zonal average climates of the annual cycle experiment and the two perpetual July experiments are alike, i.e., their differences are within limits of the natural variability of the model's climate. Statistics of various components of the GHC, i.e., water vapor, evaporation, and precipitation, are significantly affected by the presence of interactive soil moisture. A long-term trend is found in the principal empirical modes of variability of ground wetness, evaporation, and sensible heat. Dominant modes of variability of these quantities over land are physically consistent with one another and with land surface energy balance requirements. The dominant mode of precipitation variability is found to be closely related to organized convection over the tropical western Pacific Ocean. The precipitation variability has timescales in the range of 2 to 3 months and can be identified with the stationary component of the Madden-Julian Oscillation. The precipitation mode is not sensitive to the presence of interactive soil moisture but is closely linked to both the rotational and divergent components of atmospheric

  7. Method and system to estimate variables in an integrated gasification combined cycle (IGCC) plant

    DOEpatents

    Kumar, Aditya; Shi, Ruijie; Dokucu, Mustafa

    2013-09-17

    System and method to estimate variables in an integrated gasification combined cycle (IGCC) plant are provided. The system includes a sensor suite to measure respective plant input and output variables. An extended Kalman filter (EKF) receives sensed plant input variables and includes a dynamic model to generate a plurality of plant state estimates and a covariance matrix for the state estimates. A preemptive-constraining processor is configured to preemptively constrain the state estimates and covariance matrix to be free of constraint violations. A measurement-correction processor may be configured to correct constrained state estimates and a constrained covariance matrix based on processing of sensed plant output variables. The measurement-correction processor is coupled to update the dynamic model with corrected state estimates and a corrected covariance matrix. The updated dynamic model may be configured to estimate values for at least one plant variable not originally sensed by the sensor suite.

  8. Advanced heat pump cycle for district heating and cooling systems

    SciTech Connect

    Radermacher, R.

    1991-07-01

    A bread board heat pump was designed and built to test the performance of a vapor compression heat pump with two stage ammonia-water solution circuits. The design was updated based on the experience gained with the single stage version of this heat pump. A major improvement was obtained by eliminating the rectifier. The new scheme was first investigated by computer simulation and then incorporated in the experimental setup. Water balance in the high and low temperature circuits is now maintained by bleeding up to 2.5% of the weak solution flow from one solution circuit to the other. The advantages of this scheme are reduced first cost, simplified design and control, 20--30% improvement in cooling coefficient of performance and 10--15% increase in cooling capacity as compared to the cycle with a rectifier. Coefficients of performance in the range of 0.84 to 1.03 were obtained experimentally for a temperature lift of 100-K. The pressure ratios encountered were in the range of 7.6 to 9.9, which are 35 to 50% of the pressure ratio expected for a conventional heat pump. Thus the results demonstrate that high temperature lifts can be achieved at pressure ratios which are less than half as large as for conventional systems. The cooling capacities were in the range of 2.79 to 4.21 kW. 13 refs., 5 figs., 2 tabs.

  9. Thermal Cycling of Advanced Compressive Seals for Solid Oxide Fuel Cells

    SciTech Connect

    Chou, Y S.; Stevenson, Jeffry W.; CA Lewisohn; M Singh; RE Loehman

    2003-08-25

    Thermal cycling was conducted on the compressive mica seals at 800 degrees C in air. Thin ({approx}0.1 mm) Muscovite mica was pressed between a metal tube and an alumina substrate and tested for leak rates at a stress of 100 psi in the advanced design and the plain design. The advanced design involves adding two glass interlayers and was found to greatly reduce the leak rates. Two metals (Inconcl No.600 and SS430) with high and low coefficients of thermal expansion (CTE) were used to evaluate the effect of CTE mismatch on thermal cycling. The results showed that the leak rates were lower for the advanced design than the plain micas. In addition, using the lower CTE (SS430) metal tube resulted in lower leak rates as compared to Inconel No.600 metal (high CTE). In general, the leak rates abruptly increased during the first couple of cycles, and the

  10. Orbit Transfer Vehicle (OTV) advanced expander cycle engine point design study. Task 7: Engine data summary

    NASA Technical Reports Server (NTRS)

    Christensen, K. L.

    1980-01-01

    A performance optimized engine system design for a man-rated advanced LOX/hydrogen expander cycle engine was investigated. The data are presented in tables, figures, and drawings. The following categories of data for the advanced expander cycle engine are presented: engine operating specification and pressure schedule; engine system layout drawing; major component layout drawings, including thrust chamber and nozzle, extendible nozzle actuating mechanism and seal, LOX turbopump, LOX boost pump, hydrogen turbopump, hydrogen boost pump, and propellant control valves; engine performance and service life prediction; engine weight; and engine envelope. The data represent updates based upon current results from the design and analyses tasks performed under contract. Futher iterations in the designs and data can be expected as the advanced expander cycle engine design matures.

  11. Sensitivity of global terrestrial carbon cycle dynamics to variability in satellite-observed burned area

    NASA Astrophysics Data System (ADS)

    Poulter, Benjamin; Cadule, Patricia; Cheiney, Audrey; Ciais, Philippe; Hodson, Elke; Peylin, Philippe; Plummer, Stephen; Spessa, Allan; Saatchi, Sassan; Yue, Chao; Zimmermann, Niklaus E.

    2015-02-01

    Fire plays an important role in terrestrial ecosystems by regulating biogeochemistry, biogeography, and energy budgets, yet despite the importance of fire as an integral ecosystem process, significant advances remain to improve its prognostic representation in carbon cycle models. To recommend and to help prioritize model improvements, this study investigates the sensitivity of a coupled global biogeography and biogeochemistry model, LPJ, to observed burned area measured by three independent satellite-derived products, GFED v3.1, L3JRC, and GlobCarbon. Model variables are compared with benchmarks that include pantropical aboveground biomass, global tree cover, and CO2 and CO trace gas concentrations. Depending on prescribed burned area product, global aboveground carbon stocks varied by 300 Pg C, and woody cover ranged from 50 to 73 Mkm2. Tree cover and biomass were both reduced linearly with increasing burned area, i.e., at regional scales, a 10% reduction in tree cover per 1000 km2, and 0.04-to-0.40 Mg C reduction per 1000 km2. In boreal regions, satellite burned area improved simulated tree cover and biomass distributions, but in savanna regions, model-data correlations decreased. Global net biome production was relatively insensitive to burned area, and the long-term land carbon sink was robust, ~2.5 Pg C yr-1, suggesting that feedbacks from ecosystem respiration compensated for reductions in fuel consumption via fire. CO2 transport provided further evidence that heterotrophic respiration compensated any emission reductions in the absence of fire, with minor differences in modeled CO2 fluxes among burned area products. CO was a more sensitive indicator for evaluating fire emissions, with MODIS-GFED burned area producing CO concentrations largely in agreement with independent observations in high latitudes. This study illustrates how ensembles of burned area data sets can be used to diagnose model structures and parameters for further improvement and also

  12. Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 2: Advanced energy conversion systems. Part 1: Open-cycle gas turbines

    NASA Technical Reports Server (NTRS)

    Brown, D. H.; Corman, J. C.

    1976-01-01

    Ten energy conversion systems are defined and analyzed in terms of efficiency. These include: open-cycle gas turbine recuperative; open-cycle gas turbine; closed-cycle gas turbine; supercritical CO2 cycle; advanced steam cycle; liquid metal topping cycle; open-cycle MHD; closed-cycle inert gas MHD; closed-cycle liquid metal MHD; and fuel cells. Results are presented.

  13. Conventional and Advanced Silicagel-water Adsorption Cycles Driven by Near - environmental Temperature Heat

    NASA Astrophysics Data System (ADS)

    Boelman, Elisa; B. Saha, Bidyut; Tanaka, Aiharu; Kashiwagi, Takao

    This work aims at clarifying the possible operating temperature ranges for silica gel-water adsorption refrigeration cycles driven by near-environmental temperature heat sources (between 50°C and 85°C), with relatively small regenerating temperature lifts (10 K to 65 K). A newly developed three stage advanced silica gel-water cycle, which is operational with 50°C driving heat source and 30°C cooling source is introduced and compared with a conventional single stage cycle. The cycles are evaluated in terms of cooling capacity, COP and the viability of operation with near-environmental temperature driving heat sources. The analysis is based on experimental and cycle simulation work. The results showed the advanced three stage cycle to be particularly suited for operation with low grade waste heat driving sources, since it worked with small regenerating temperature lifts (ΔTregen)of 10K to 30K. Another significant advantage of operation with small ΔTregen is the possibility to reduce irreversible heat losses from batched cycle operation. Experiments carried out on full-size machine suggested that, even with smallΔTregen, adsorber /desorber heat exchanger improvements such as higher thermal conductance and smaller heat capacitance can contribute to reduce heat losses while improving cycle performance in terms of cooling capacity and COP.

  14. Advanced reactors and associated fuel cycle facilities: safety and environmental impacts.

    PubMed

    Hill, R N; Nutt, W M; Laidler, J J

    2011-01-01

    The safety and environmental impacts of new technology and fuel cycle approaches being considered in current U.S. nuclear research programs are contrasted to conventional technology options in this paper. Two advanced reactor technologies, the sodium-cooled fast reactor (SFR) and the very high temperature gas-cooled reactor (VHTR), are being developed. In general, the new reactor technologies exploit inherent features for enhanced safety performance. A key distinction of advanced fuel cycles is spent fuel recycle facilities and new waste forms. In this paper, the performance of existing fuel cycle facilities and applicable regulatory limits are reviewed. Technology options to improve recycle efficiency, restrict emissions, and/or improve safety are identified. For a closed fuel cycle, potential benefits in waste management are significant, and key waste form technology alternatives are described. PMID:21399407

  15. Advanced Fuel Cycle Initiative - Projected Linear Heat Generation Rate and Burnup Calculations

    SciTech Connect

    Richard G. Ambrosek; Gray S. Chang; Debbie J. Utterbeck

    2005-02-01

    This report provides documentation of the physics analysis performed to determine the linear heat generation rate (LHGR) and burnup calculations for the Advanced Fuel Cycle Initiative (AFCI) tests, AFC-1D, AFC-1H, and AFC-1G. The AFC-1D and AFC-1H tests consists of low-fertile metallic fuel compositions and the AFC-1G test consists of non-fertile and low-fertile nitride compositions. These tests will be irradiated in the East Flux Trap (EFT) positions E1, E2, and E3, respectively, during Advanced Test Reactor (ATR) Cycle 135B.

  16. Recovery of Information from the Fast Flux Test Facility for the Advanced Fuel Cycle Initiative

    SciTech Connect

    Nielsen, Deborah L.; Makenas, Bruce J.; Wootan, David W.; Butner, R. Scott; Omberg, Ronald P.

    2009-09-30

    The Fast Flux Test Facility is the most recent Liquid Metal Reactor to operate in the United States. Information from the design, construction, and operation of this reactor was at risk as the facilities associated with the reactor are being shut down. The Advanced Fuel Cycle Initiative is a program managed by the Office of Nuclear Energy of the U.S. Department of Energy with a mission to develop new fuel cycle technologies to support both current and advanced reactors. Securing and preserving the knowledge gained from operation and testing in the Fast Flux Test Facility is an important part of the Knowledge Preservation activity in this program.

  17. Repowering with an integrated gasification-cascaded humidified advanced turbine (IG-CHAT) cycle

    SciTech Connect

    Freier, M.D.; Goldstein, H.N.; Swensen, E.C.

    1998-12-31

    This paper presents the results of an evaluation of repowering a typical US based coal fired power plant with a combination of coal gasification and advanced turbine technologies. In this case, an oxygen blown, fixed bed gasifier (based on British Gas-Lurgi technology) generates clean, low temperature, medium Btu gas which is fired in an advanced type of power cycle; namely, the Cascaded Humidified Advanced Turbine, or CHAT cycle which is defined and described below. This conceptual site repowering follows the same methodology and uses the same design parameters as in a recent evaluation of plant repowering utilizing a broad suite of advanced technologies, many of which are currently being demonstrated in the Clean Coal Technology Demonstration Program.

  18. Solar Cycle Variability in Mean Thermospheric Composition and Temperature Induced by Atmospheric Tides

    NASA Astrophysics Data System (ADS)

    Jones, M., Jr.; Forbes, J. M.; Hagan, M. E.

    2015-12-01

    Vertically-propagating atmospheric thermal tides whose origins lie in Earth's lower atmosphere are now widely recognized as one of the dominant "meteorological" drivers of space weather. Many prior research efforts have focused on documenting and understanding the role that dissipating tides play in determining the longitudinal and seasonal variability associated with lower thermospheric winds, temperature, and constituent densities. However, considerably less attention has focused on understanding the potential solar cycle variability in the mean thermospheric state induced by the tides. In this paper we utilize the National Center for Atmospheric Research Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM), forced with observationally-based tides at the model lower boundary from the Climatological Tidal Model of the Thermosphere (CTMT, from Oberheide et al. [2011]), to elucidate how the dissipating tides induce variations of up to 30 K in the zonal-mean thermosphere temperature between solar minimum and maximum. Numerical experiments are performed for the month of September and for solar minimum, medium, and maximum conditions in order to quantify the solar cycle variability associated with the different terms in the thermodynamic energy, major and minor neutral constituent continuity equations. Our analysis indicates that solar cycle variability in neutral temperatures results from a combination of net eddy heat transport effects and tidal modulation of net nitric oxide (NO) cooling. The chemical and dynamical pathways through which dissipating tides affect mean NO cooling differently at solar minimum and maximum are diagnosed.

  19. Diurnal variability of the hydrologic cycle in a general circulation model

    NASA Technical Reports Server (NTRS)

    Randall, David A.; Dazlich, Donald A.; HARSHVARDHAN

    1991-01-01

    In the present Colorado State University GCM simulation-based analysis of the diurnal and semidiurnal variability of precipitation, precipitable water, evaporation, cloudiness, horizontal moisture flux convergence, and cloud radiative forcing, a realistic afternoon precipitation maximum is obtained over land in warm rainy regions, as well as an early morning maximum over the oceans. The model has been further used to investigate the bases for the oceanic diurnal-precipitation cycle; the results thus obtained indicate that such an oceanic cycle occurs even in the absence of neighboring continents, and tends to have a morning maximum, although the observed phenomenon is generally stronger than the results indicate.

  20. Recent X-ray Observations of Stellar Cycles and Long Term Variability

    NASA Astrophysics Data System (ADS)

    Peres, G.; Micela, G.; et al.

    2006-08-01

    We will discuss some aspects relevant to the detection of coronal activity cycles in late-type stars. The effects of the activity solar cycle manifest themselves in many bands, and most notably in the X-ray band. Since strong X-ray emission and other forms of activity are very evident in active late-type stars, one would expect detection of analogous X-ray cycles on these stars. However this is not the case. So to which extent can we apply the Solar-stellar connection in the coronal context? Certainly the Sun fits in the general late-type-stars "trend" of activity vs. rotation, age, temperature, flux etc.; on the other side extreme stellar activity shows "saturation" in rapidly rotating stars and the above "trend" may change significantly or break for very active stars, suggesting the action of a mechanism different from the solar-type dynamo. In this context, proving the presence of coronal solar-like cycles and determining their characteristics, hopefully for a large stellar sample, would provide fundamental tests. Detecting stellar coronal cycles is difficult, given the limited availability of present day X-ray telescopes for this purpose. Also, since X-ray observations aimed at cycle determinations cover time intervals much shorter than cycles themselves, and separated by years, it is hard to disentangle the mix of short term variability and cycles. Nonetheless there is some evidence of long term variability in some samples and in relatively old solar-mass stars (but not in young solar-mass stars neither in M stars). Some projects dedicated to find X-ray cycles using present day telescopes (e.g. those driven by Schmitt and by Favata) have started yielding results. A possibly more fruitful approach to detecting X-ray cycles is devising a relatively small X-ray satellite entirely dedicated to a long observing program to monitor active stars, like SADE (recently proposed by P. Martens and collaborators). One of the important goals of this research would be tracing

  1. Advanced Fuel Cycle Economic Analysis of Symbiotic Light-Water Reactor and Fast Burner Reactor Systems

    SciTech Connect

    D. E. Shropshire

    2009-01-01

    The Advanced Fuel Cycle Economic Analysis of Symbiotic Light-Water Reactor and Fast Burner Reactor Systems, prepared to support the U.S. Advanced Fuel Cycle Initiative (AFCI) systems analysis, provides a technology-oriented baseline system cost comparison between the open fuel cycle and closed fuel cycle systems. The intent is to understand their overall cost trends, cost sensitivities, and trade-offs. This analysis also improves the AFCI Program’s understanding of the cost drivers that will determine nuclear power’s cost competitiveness vis-a-vis other baseload generation systems. The common reactor-related costs consist of capital, operating, and decontamination and decommissioning costs. Fuel cycle costs include front-end (pre-irradiation) and back-end (post-iradiation) costs, as well as costs specifically associated with fuel recycling. This analysis reveals that there are large cost uncertainties associated with all the fuel cycle strategies, and that overall systems (reactor plus fuel cycle) using a closed fuel cycle are about 10% more expensive in terms of electricity generation cost than open cycle systems. The study concludes that further U.S. and joint international-based design studies are needed to reduce the cost uncertainties with respect to fast reactor, fuel separation and fabrication, and waste disposition. The results of this work can help provide insight to the cost-related factors and conditions needed to keep nuclear energy (including closed fuel cycles) economically competitive in the U.S. and worldwide. These results may be updated over time based on new cost information, revised assumptions, and feedback received from additional reviews.

  2. Rolls-Royce Low Noise Highly Variable Cycle Nozzle for Next Generation Supersonic Aircraft

    NASA Technical Reports Server (NTRS)

    Sokhey, Jack S.; Kube-McDowell, Matthew

    2008-01-01

    An overview of the work performed by Rolls-Royce under contract NNL08AA29C is presented. The work includes computational fluid dynamic (CFD) analysis for, and design of, a highly variable cycle exhaust model for the Supersonic project (NRA NN06ZEA001N). The CFD analysis shows that the latest design improvements to the clam shell doors have increased flow through the ejector over that achieved with previous designs.

  3. Assessment of Variable-cycle Engines for Mach 2.7 Supersonic Transports

    NASA Technical Reports Server (NTRS)

    Morris, S. J.; Foss, W. E., Jr.; Russell, J. W.

    1976-01-01

    Three proposed SCAR propulsion systems in terms of aircraft range for a fixed payload and take-off gross weight with a design cruise Mach number 2.7 are evaluated. The effects of various noise and operational restraints are determined and sensitivities to some of the more important performance variables are presented for the most probable design noise and operational restraint case. Critical areas requiring new or improved technology for each cycle are delineated.

  4. Thermodynamic modeling and performance analysis of the variable-temperature heat reservoir absorption heat pump cycle

    NASA Astrophysics Data System (ADS)

    Qin, Xiaoyong; Chen, Lingen; Ge, Yanlin; Sun, Fengrui

    2015-10-01

    For practical absorption heat pump (AHP) plants, not all external heat reservoir heat capacities are infinite. External heat reservoir heat capacity should be an effect factor in modeling and performance analysis of AHP cycles. A variable-temperature heat reservoir AHP cycle is modeled, in which internal working substance is working in four temperature levels and all irreversibility factors are considered. The irreversibility includes heat transfer irreversibility, internal dissipation irreversibility and heat leakage irreversibility. The general equations among coefficient of performance (COP), heating load and some key characteristic parameters are obtained. The general and optimal characteristics are obtained by using numerical calculations. Besides, the influences of heat capacities of heat reservoirs, internal dissipation irreversibility, and heat leakage irreversibility on cycle performance are analyzed. The conclusions can offer some guidelines for design and operation of AHP plants.

  5. Analysis of life cycle costs for electric vans with advanced battery systems

    SciTech Connect

    Marr, W.W.; Walsh, W.J.; Miller, J.F.

    1988-11-01

    The performance of advanced Zn/Br/sub 2/, LiAl/FeS, Na/S, Ni/Fe, and Fe/Air batteries in electric vans was compared to that of tubular lead-acid technology. The MARVEL computer analysis system evaluated these batteries for the G-Van and IDSEP vehicles over two driving schedules. Each of the advanced batteries exhibited the potential for major improvements in both range and life cycle cost compared with tubular lead-acid. A sensitivity analysis revealed specific energy, battery initial cost, and cycle life to be the dominant factors in reducing life cycle cost for the case of vans powered by tubular lead-acid batteries. 5 refs., 8 figs., 2 tabs.

  6. Analysis of life cycle costs for electric vans with advanced battery systems

    SciTech Connect

    Marr, W.W.; Walsh, W.J.; Miller, J.F.

    1989-01-01

    The performance of advanced Zn/Br/sub 2/, LiAl/FeS, Na/S, Ni/Fe, and Fe/Air batteries in electric vans was compared to that of tubular lead-acid technology. The MARVEL computer analysis system evaluated these batteries for the G-Van and IDSEP vehicles over two driving schedules. Each of the advanced batteries exhibited the potential for major improvements in both range and life cycle cost compared with tubular lead-acid. A sensitivity analysis reveals specific energy, battery initial cost, and cycle life to be the dominant factors in reducing life cycle cost for the case of vans powered by tubular lead-acid batteries.

  7. Closing the US Fuel Cycle: Siting Considerations for the Global Nuclear Energy Partnership Facilities - Siting the Advanced Fuel Cycle Facility

    SciTech Connect

    Griffith, A.; Boger, J.; Perry, J.

    2008-07-01

    The Global Nuclear Energy Partnership (GNEP), launched in February, 2006, proposes to introduce used nuclear fuel recycling in the United States (U.S.) with improved proliferation-resistance and a more effective waste management approach. This program is evaluating ways to close the fuel cycle in a manner that introduces the most advanced technologies of today and builds on recent breakthroughs in U.S. national laboratories while drawing on international and industry partnerships. Central to moving this advanced fuel recycling technology from the laboratory to commercial implementation is the development and siting of three proposed GNEP facilities: the Consolidated Fuel Treatment Center (CFTC), the Advanced Burner Reactor (ABR), and the Advanced Fuel Cycle Facility (AFCF). These three projects are envisioned to introduce used fuel separations, advanced fuel fabrication, and fast reactor technology in a manner that efficiently recycles material, produces the most energy out of the existing inventory of used fuel, and improves our ability to manage nuclear waste. The CFTC and ABR are sited under GNEP but will depend on industry involvement and will not be covered by this paper. This paper will cover considerations for siting the AFCF. The AFCF will provide the U.S. with the capabilities required to evaluate technologies that separate used fuel into reusable material and waste in a proliferation-resistant manner. The separations technology demonstration capability is coupled with a remote transmutation fuel fabrication demonstration capability in an integrated manner that demonstrates advanced safeguard technologies. In conclusion: As a flexible, multi-purpose demonstration facility, the AFCF will provide the U.S. with a powerful and unique capability to quickly bring innovative nuclear fuel recycling technology from the laboratory to the commercial market with high confidence. The siting of AFCF capabilities at one or more of the six DOE laboratories being evaluated

  8. Advanced oxidation degradation kinetics as a function of ultraviolet LED duty cycle.

    PubMed

    Duckworth, Kelsey; Spencer, Michael; Bates, Christopher; Miller, Michael E; Almquist, Catherine; Grimaila, Michael; Magnuson, Matthew; Willison, Stuart; Phillips, Rebecca; Racz, LeeAnn

    2015-01-01

    Ultraviolet (UV) light emitting diodes (LEDs) may be a viable option as a UV light source for advanced oxidation processes (AOPs) utilizing photocatalysts or oxidizing agents such as hydrogen peroxide. The effect of UV-LED duty cycle, expressed as the percentage of time the LED is powered, was investigated in an AOP with hydrogen peroxide, using methylene blue (MB) to assess contaminant degradation. The UV-LED AOP degraded the MB at all duty cycles. However, adsorption of MB onto the LED emitting surface caused a linear decline in reactor performance over time. With regard to the effect of duty cycle, the observed rate constant of MB degradation, after being adjusted to account for the duty cycle, was greater for 5 and 10% duty cycles than higher duty cycles, providing a value approximately 160% higher at 5% duty cycle than continuous operation. This increase in adjusted rate constant at low duty cycles, as well as contaminant fouling of the LED surface, may impact design and operational considerations for pulsed UV-LED AOP systems. PMID:25945855

  9. Clinical Significance of CA125 Level after the First Cycle of Chemotherapy on Survival of Patients with Advanced Ovarian Cancer

    PubMed Central

    Lee, Maria; Chang, Min Young; Yoo, Hanna; Lee, Kyung Eun; Chay, Doo Byung; Cho, Hanbyoul; Kim, Young Tae

    2016-01-01

    Purpose To determine the most powerful cancer antigen 125 (CA125)-related prognostic factor for advanced epithelial ovarian cancer (EOC) and to identify cut-off values that distinguish patients with a poor prognosis from those with a good prognosis. Materials and Methods We included 223 patients who received staging laparotomy and were diagnosed with stage IIC–IV serous EOC. Cox regression analysis was used to determine the most significant prognostic factor among the following variables: serum CA125 before surgery and after the first, second, and sixth cycles of chemotherapy; the nadir CA125 value; the relative percentage change in CA125 levels after the first and second cycles of chemotherapy compared to baseline CA125; CA125 half-life; time to nadir; and time to normalization of the CA125 level. Results The CA125 level after the first chemotherapy cycle was the most significant independent prognostic factor for overall survival (OS). Time to normalization (p=0.028) and relative percentage change between CA125 levels at baseline and after the first chemotherapy cycle (p=0.021) were additional independent prognostic factors in terms of OS. The CA125 level after the first chemotherapy cycle (p=0.001) and time to normalization (p<0.001) were identified as independent prognostic factors for progression free survival (PFS). Conclusion Among well-established CA125-related prognostic factors, serum CA125 levels after the first cycle of chemotherapy and time to normalization were the most significant prognostic factors for both OS and PFS. PMID:26996555

  10. Geomorphic and substrate controls on spatial variability in river solute transport and biogeochemical cycling

    NASA Astrophysics Data System (ADS)

    Blaen, Phillip; Kurz, Marie; Knapp, Julia; Mendoza-Lera, Clara; Lee-Cullin, Joe; Klaar, Megan; Drummond, Jen; Jaeger, Anna; Zarnetske, Jay; Lewandowski, Joerg; Marti, Eugenia; Ward, Adam; Fleckenstein, Jan; Datry, Thibault; Larned, Scott; Krause, Stefan

    2016-04-01

    Nutrient concentrations in surface waters and groundwaters are increasing in many agricultural catchments worldwide as a result of anthropogenic activities. Increasing geomorphological heterogeneity in river channels may help to attenuate nutrient pollution by facilitating water exchange fluxes with the hyporheic zone; a site of intense microbial activity where biogeochemical transformation rates (e.g. denitrification) can be high. However, the controls on spatial variability in biogeochemical cycling, particularly at scales relevant for river managers, are not well understood. Here, we aimed to assess: 1) how differences in geomorphological heterogeneity control river solute transport and rates of biogeochemical cycling at sub-reach scales (102 m); and 2) the relative magnitude of these differences versus those relating to reach scale substrate variability (103 m). We used the reactive 'smart' tracer resazurin (Raz), a weakly fluorescent dye that transforms to highly fluorescent resorufin (Rru) under mildly reducing conditions, as a proxy to assess rates of biogeochemical cycling in a lowland river in southern England. Solute tracer tests were conducted in two reaches with contrasting substrates: one sand-dominated and the other gravel-dominated. Each reach was divided into sub-reaches that varied in geomorphic complexity (e.g. by the presence of pool-riffle sequences or the abundance of large woody debris). Slug injections of Raz and the conservative tracer fluorescein were conducted in each reach during baseflow conditions (Q ≈ 80 L/s) and breakthrough curves monitored using in-situ fluorometers. Preliminary results indicate overall Raz:Rru transformation rates in the gravel-dominated reach were more than 50% higher than those in the sand-dominated reach. However, high sub-reach variability in Raz:Rru transformation rates and conservative solute transport parameters suggests small-scale targeted management interventions to alter geomorphic heterogeneity may be

  11. Ecological controls on water-cycle response to climate variability in deserts.

    PubMed

    Scanlon, B R; Levitt, D G; Reedy, R C; Keese, K E; Sully, M J

    2005-04-26

    The impact of climate variability on the water cycle in desert ecosystems is controlled by biospheric feedback at interannual to millennial timescales. This paper describes a unique field dataset from weighing lysimeters beneath nonvegetated and vegetated systems that unequivocally demonstrates the role of vegetation dynamics in controlling water cycle response to interannual climate variability related to El Nino southern oscillation in the Mojave Desert. Extreme El Nino winter precipitation (2.3-2.5 times normal) typical of the U.S. Southwest would be expected to increase groundwater recharge, which is critical for water resources in semiarid and arid regions. However, lysimeter data indicate that rapid increases in vegetation productivity in response to elevated winter precipitation reduced soil water storage to half of that in a nonvegetated lysimeter, thereby precluding deep drainage below the root zone that would otherwise result in groundwater recharge. Vegetation dynamics have been controlling the water cycle in interdrainage desert areas throughout the U.S. Southwest, maintaining dry soil conditions and upward soil water flow since the last glacial period (10,000-15,000 yr ago), as shown by soil water chloride accumulations. Although measurements are specific to the U.S. Southwest, correlations between satellite-based vegetation productivity and elevated precipitation related to El Nino southern oscillation indicate this model may be applicable to desert basins globally. Understanding the two-way coupling between vegetation dynamics and the water cycle is critical for predicting how climate variability influences hydrology and water resources in water-limited landscapes. PMID:15837922

  12. ENSO variability from mid- to late Holocene and the Seasonal Cycle of SST off Peru

    NASA Astrophysics Data System (ADS)

    Loubere, Paul; Volk, Kate; Cumpston, Jennifer

    2010-05-01

    The El-Nino Southern Oscillation impacts environmental conditions across the tropical Pacific and, via teleconnection, feeds into climate across the globe. The degree to which ENSO is variable, and how this relates to global climate conditions, is a key issue for regional climate dynamics, marine biological resources and feedback analysis within the planetary climate system. The response of ENSO to global warming remains an open question. ENSO variability has been linked, in theoretical work, to both atmospheric dynamics and thermocline circulation in the eastern equatorial Pacific. Key factors are the seasonal cycle in strength of the meridional SST gradient in the eastern equatorial Pacific, and temperature and depth of the thermocline. These feed into an annual cycle which provides the trigger for ENSO state switching. There are various theories about the way that the key factors interact to control ENSO activity. We test these theories with an analysis of upwelling temperatures, and their seasonal cycle, for selected time intervals from the mid-Holocene of Peru. Lake records of El Nino frequency from Ecuador indicate that ENSO activity has varied on the millennial to centennial timescale from the mid-Holocene to the Present. We identify three time periods when ENSO variability was apparently minimized, in an intermediate state, and maximized. We examine these time intervals using sub-annual sampling of the stable isotopes of mollusk shell growth bands. We test whether the changes in El Nino frequency inferred from the lake deposits are supported by independent records from coastal Peru, and we test whether changes in annual cycle of SST and/or thermocline temperatures can account for the differences in El Nino activity as expected from theoretical considerations.

  13. Advanced Multi-Effect Distillation System for Desalination Using Waste Heat fromGas Brayton Cycles

    SciTech Connect

    Haihua Zhao; Per F. Peterson

    2012-10-01

    Generation IV high temperature reactor systems use closed gas Brayton Cycles to realize high thermal efficiency in the range of 40% to 60%. The waste heat is removed through coolers by water at substantially greater average temperature than in conventional Rankine steam cycles. This paper introduces an innovative Advanced Multi-Effect Distillation (AMED) design that can enable the production of substantial quantities of low-cost desalinated water using waste heat from closed gas Brayton cycles. A reference AMED design configuration, optimization models, and simplified economics analysis are presented. By using an AMED distillation system the waste heat from closed gas Brayton cycles can be fully utilized to desalinate brackish water and seawater without affecting the cycle thermal efficiency. Analysis shows that cogeneration of electricity and desalinated water can increase net revenues for several Brayton cycles while generating large quantities of potable water. The AMED combining with closed gas Brayton cycles could significantly improve the sustainability and economics of Generation IV high temperature reactors.

  14. Modeling Menstrual Cycle Length and Variability at the Approach of Menopause Using Hierarchical Change Point Models

    PubMed Central

    Huang, Xiaobi; Elliott, Michael R.; Harlow, Siobán D.

    2013-01-01

    SUMMARY As women approach menopause, the patterns of their menstrual cycle lengths change. To study these changes, we need to jointly model both the mean and variability of cycle length. Our proposed model incorporates separate mean and variance change points for each woman and a hierarchical model to link them together, along with regression components to include predictors of menopausal onset such as age at menarche and parity. Additional complexity arises from the fact that the calendar data have substantial missingness due to hormone use, surgery, and failure to report. We integrate multiple imputation and time-to event modeling in a Bayesian estimation framework to deal with different forms of the missingness. Posterior predictive model checks are applied to evaluate the model fit. Our method successfully models patterns of women’s menstrual cycle trajectories throughout their late reproductive life and identifies change points for mean and variability of segment length, providing insight into the menopausal process. More generally, our model points the way toward increasing use of joint mean-variance models to predict health outcomes and better understand disease processes. PMID:24729638

  15. Neuromuscular and physiological variables evolve independently when running immediately after cycling.

    PubMed

    Walsh, Joel A; Stamenkovic, Alexander; Lepers, Romuald; Peoples, Gregory; Stapley, Paul J

    2015-12-01

    During the early period of running after cycling, EMG patterns of the leg are modified in only some highly trained triathletes. The majority of studies have analysed muscle EMG patterns at arbitrary, predetermined time points. The purpose of this study was to examine changes to EMG patterns of the lower limb at physiologically determined times during the cycle-run transition period to better investigate neuromuscular adaptations. Six highly trained triathletes completed a 10 m in isolated run (IR), 30 min of rest, then a 20 min cycling procedure, before a 10 min transition run (C-R). Surface EMG activity of eight lower limb muscles was recorded, normalised and quantified at four time points. Oxygen uptake and heart rate values were also collected. Across all muscles, mean (± SD) EMG patterns, demonstrated significant levels of reproducibility for each participant at all four time points (α < 0.05; r = 0.52-0.97). Mean EMG patterns during C-R correlated highly with the IR patterns (α < 0.05). These results show that EMG patterns during subsequent running are not significantly affected by prior cycling. However, variability of muscle recruitment activity does appear to increase during C-R transition when compared to IR. PMID:26542485

  16. A prospective study of variability in mammographic density during the menstrual cycle.

    PubMed

    Morrow, Monica; Chatterton, Robert T; Rademaker, Alfred W; Hou, Nanjiang; Jordan, V Craig; Hendrick, R Edward; Khan, Seema A

    2010-06-01

    Mammographic breast density has been proposed as a surrogate endpoint in breast cancer prevention studies, but little is known about its variability over time, particularly in relation to menstrual cycle phase. The purpose of this study was to assess variation in breast density on digital mammograms using quantitative and qualitative density measures. Menstrual cycle phase was determined by salivary estradiol and progesterone assays. 73 healthy subjects with regular menses had 1-3 mammograms with paired saliva collection during a 12-month period. The mean difference in density as a percentage of the mean density was calculated for follicular-luteal (n = 50), luteal-luteal (n = 26) and follicular-follicular (n = 23) pairs in the same woman using the same breast. Two density measures (measurement of dense area and BIRADS) were used. The mean luteal density exceeded the mean follicular density by 7.1-9.2%, but density differences between luteal pairs and follicular pairs did not exceed 5%. The intraclass correlation for measurement of dense area was greater than 85% in all phases of the menstrual cycle, but was below 50% for BIRADS for luteal-follicular and follicular-follicular pairs. Our study provides estimates of the amount of variation in mammographic density during the menstrual cycle, and that inherent in repeated density measurement in premenopausal women, and suggests that menstrual phase of mammographic evaluation should be controlled for in intervention studies where density is being used as a surrogate measure. PMID:19669673

  17. Sensitivity of Northern Hemisphere ice sheets to AMOC variability during the last glacial cycle

    NASA Astrophysics Data System (ADS)

    Heinemann, Malte; Timmermann, Axel; Friedrich, Tobias; Pollard, David

    2016-04-01

    The ocean played an instrumental role during the last glacial cycle, not only as a carbon trap but also during Dansgaard-Oeschger and Heinrich events. But did the variability of the ocean circulation on timescales of hundreds to a few thousand years also affect the long-term evolution of the Northern Hemisphere ice sheets? We address this question using stand-alone ice sheet - ice shelf model simulations of the last glacial cycle. The boundary conditions for these simulations are derived from simulations with the intermediate complexity earth system model LOVECLIM, and from an estimate of past Atlantic meridional overturning circulation (AMOC) changes based on SST reconstructions. First ice model results suggest that interruptions of the AMOC may have supported the ice sheet build-up during the glacial inception. In particular, during Marine Isotope Stage 3, the AMOC interruptions may have stabilised the Laurentide ice sheet via surface cooling, rather than destabilised it via subsurface warming.

  18. Definition study of a Variable Cycle Experimental Engine (VCEE) and associated test program and test plan

    NASA Technical Reports Server (NTRS)

    Allan, R. D.

    1978-01-01

    The Definition Study of a Variable Cycle Experimental Engine (VCEE) and Associated Test Program and Test Plan, was initiated to identify the most cost effective program for a follow-on to the AST Test Bed Program. The VCEE Study defined various subscale VCE's based on different available core engine components, and a full scale VCEE utilizing current technology. The cycles were selected, preliminary design accomplished and program plans and engineering costs developed for several program options. In addition to the VCEE program plans and options, a limited effort was applied to identifying programs that could logically be accomplished on the AST Test Bed Program VCE to extend the usefulness of this test hardware. Component programs were provided that could be accomplished prior to the start of a VCEE program.

  19. Comparison of intergrated coal gasification combined cycle power plants with current and advanced gas turbines

    SciTech Connect

    Banda, B.M.; Evans, T.F.; McCone, A.I.; Westisik, J.H.

    1984-08-01

    Two recent conceptual design studies examined ''grass roots'' integrated gasification-combined cycle (IGCC) plants for the Albany Station site of Niagara Mohawk Power Corporation. One of these studies was based on the Texaco Gasifier and the other was developed around the British Gas Co.-Lurgi slagging gasifier. Both gasifiers were operated in the ''oxygen-blown'' mode, producing medium Btu fuel gas. The studies also evaluated plant performance with both current and advanced gas turbines. Coalto-busbar efficiencies of approximately 35 percent were calculated for Texaco IGCC plants using current technology gas turbines. Efficiencies of approximately 39 percent were obtained for the same plant when using advanced technology gas turbines.

  20. Advanced Rankine and Brayton cycle power systems: Materials needs and opportunities

    NASA Technical Reports Server (NTRS)

    Grisaffe, S. J.; Guentert, D. C.

    1974-01-01

    Conceptual advanced potassium Rankine and closed Brayton power conversion cycles offer the potential for improved efficiency over steam systems through higher operating temperatures. However, for utility service of at least 100,000 hours, materials technology advances will be needed for such high temperature systems. Improved alloys and surface protection must be developed and demonstrated to resist coal combustion gases as well as potassium corrosion or helium surface degradation at high temperatures. Extensions in fabrication technology are necessary to produce large components of high temperature alloys. Long time property data must be obtained under environments of interest to assure high component reliability.

  1. Advanced Rankine and Brayton cycle power systems - Materials needs and opportunities

    NASA Technical Reports Server (NTRS)

    Grisaffe, S. J.; Guentert, D. C.

    1974-01-01

    Conceptual advanced potassium Rankine and closed Brayton power conversion cycles offer the potential for improved efficiency over steam systems through higher operating temperatures. However, for utility service of at least 100,000 hours, materials technology advances will be needed for such high temperature systems. Improved alloys and surface protection must be developed and demonstrated to resist coal combustion gases as well as potassium corrosion or helium surface degradation at high temperatures. Extensions in fabrication technology are necessary to produce large components of high temperature alloys. Long-time property data must be obtained under environments of interest to assure high component reliability.

  2. Nuclear Systems Enhanced Performance Program, Maintenance Cycle Extension in Advanced Light Water Reactor Design

    SciTech Connect

    Professor Neill Todreas

    2001-10-01

    A renewed interest in new nuclear power generation in the US has spurred interest in developing advanced reactors with features which will address the public's concerns regarding nuclear generation. However, it is economic performance which will dictate whether any new orders for these plants will materialize. Economic performance is, to a great extent, improved by maximizing the time that the plant is on-line generating electricity relative to the time spent off-line conducting maintenance and refueling. Indeed, the strategy for the advanced light water reactor plant IRIS (International Reactor, Innovative and Secure) is to utilize an eight year operating cycle. This report describes a formalized strategy to address, during the design phase, the maintenance-related barriers to an extended operating cycle. The top-level objective of this investigation was to develop a methodology for injecting component and system maintainability issues into the reactor plant design process to overcome these barriers. A primary goal was to demonstrate the applicability and utility of the methodology in the context of the IRIS design. The first step in meeting the top-level objective was to determine the types of operating cycle length barriers that the IRIS design team is likely to face. Evaluation of previously identified regulatory and investment protection surveillance program barriers preventing a candidate operating PWR from achieving an extended (48 month) cycle was conducted in the context of the IRIS design. From this analysis, 54 known IRIS operating cycle length barriers were identified. The resolution methodology was applied to each of these barriers to generate design solution alternatives for consideration in the IRIS design. The methodology developed has been demonstrated to narrow the design space to feasible design solutions which enable a desired operating cycle length, yet is general enough to have broad applicability. Feedback from the IRIS design team indicates

  3. Effect of Different Phases of Menstrual Cycle on Heart Rate Variability (HRV)

    PubMed Central

    Singh, K. D.; Kumar, Avnish

    2015-01-01

    Background Heart Rate Variability (HRV), which is a measure of the cardiac autonomic tone, displays physiological changes throughout the menstrual cycle. The functions of the ANS in various phases of the menstrual cycle were examined in some studies. Aims and Objectives The aim of our study was to observe the effect of menstrual cycle on cardiac autonomic function parameters in healthy females. Materials and Methods A cross-sectional (observational) study was conducted on 50 healthy females, in the age group of 18-25 years. Heart Rate Variability (HRV) was recorded by Physio Pac (PC-2004). The data consisted of Time Domain Analysis and Frequency Domain Analysis in menstrual, proliferative and secretory phase of menstrual cycle. Data collected was analysed statistically using student’s pair t-test. Results The difference in mean heart rate, LF power%, LFnu and HFnu in menstrual and proliferative phase was found to be statistically significant. The difference in mean RR, Mean HR, RMSSD (the square root of the mean of the squares of the successive differences between adjacent NNs.), NN50 (the number of pairs of successive NNs that differ by more than 50 ms), pNN50 (the proportion of NN50 divided by total number of NNs.), VLF (very low frequency) power, LF (low frequency) power, LF power%, HF power %, LF/HF ratio, LFnu and HFnu was found to be statistically significant in proliferative and secretory phase. The difference in Mean RR, Mean HR, LFnu and HFnu was found to be statistically significant in secretory and menstrual phases. Conclusion From the study it can be concluded that sympathetic nervous activity in secretory phase is greater than in the proliferative phase, whereas parasympathetic nervous activity is predominant in proliferative phase. PMID:26557512

  4. Study on the variable cycle engine modeling techniques based on the component method

    NASA Astrophysics Data System (ADS)

    Zhang, Lihua; Xue, Hui; Bao, Yuhai; Li, Jijun; Yan, Lan

    2016-01-01

    Based on the structure platform of the gas turbine engine, the components of variable cycle engine were simulated by using the component method. The mathematical model of nonlinear equations correspondeing to each component of the gas turbine engine was established. Based on Matlab programming, the nonlinear equations were solved by using Newton-Raphson steady-state algorithm, and the performance of the components for engine was calculated. The numerical simulation results showed that the model bulit can describe the basic performance of the gas turbine engine, which verified the validity of the model.

  5. Quasiperiodicity in cataclysmic variable stars caused by solar-type magnetic cycles

    NASA Technical Reports Server (NTRS)

    Warner, Brian

    1988-01-01

    Cyclical variations of orbital periods, quiescent magnitudes and outburst intervals in the activity of cataclysmic variable binary stars are inter-related and are ascribed to variations in radii of the secondaries, caused by solar-type (sunspot) magnetic cycles. In the nova remnant DQ Herculis the observed variations in orbital period and quiescent magnitude are consistent with this mechanism. But accretion onto the white dwarf, from an accretion disk acquired from its companion, cannot explain the observed variation of the 71-second oscillations.

  6. Advancing Variable Star Astronomy: The Centennial History of the American Association of Variable Star Observers

    NASA Astrophysics Data System (ADS)

    Williams, Thomas R.; Saladyga, Michael

    2011-05-01

    Preface; Part I. Pioneers in Variable Star Astronomy Prior to 1909: 1. The emergence of variable star astronomy - a need for observations; 2. A need for observers; Part II. The Founding of the AAVSO - The William Tyler Olcott Era: 3. The amateur's amateur; 4. Amateurs in the service of science; Part III. The Leon Campbell Era: 5. Leon Campbell to the rescue; 6. Formalizing relationships; 7. The Pickering Memorial Endowment; 8. Fading of the Old Guard; 9. Growing pains and distractions; Part IV. The Service Bureau - The Margaret Mayall Era: 10. Learning about independence; 11. Eviction from Harvard College Observatory; 12. Actions and reactions; 13. In search of a home; 14. Survival on Brattle Street; 15. AAVSO achievements; 16. Breathing room on Concord Avenue; Part V. Analysis and Science: The Janet Mattei Era: 17. The growth of a director; 18. Learning the ropes the hard way; 19. Managing with renewed confidence; 20. Expanding the scientific charter; Part VI. Accelerating Observational Science - The Arne Henden Era: 21. Bridging the gap; 22. Accelerating the science - the Henden era begins; Epilogue; Appendices; Index.

  7. Advanced Launch Technology Life Cycle Analysis Using the Architectural Comparison Tool (ACT)

    NASA Technical Reports Server (NTRS)

    McCleskey, Carey M.

    2015-01-01

    Life cycle technology impact comparisons for nanolauncher technology concepts were performed using an Affordability Comparison Tool (ACT) prototype. Examined are cost drivers and whether technology investments can dramatically affect the life cycle characteristics. Primary among the selected applications was the prospect of improving nanolauncher systems. As a result, findings and conclusions are documented for ways of creating more productive and affordable nanolauncher systems; e.g., an Express Lane-Flex Lane concept is forwarded, and the beneficial effect of incorporating advanced integrated avionics is explored. Also, a Functional Systems Breakdown Structure (F-SBS) was developed to derive consistent definitions of the flight and ground systems for both system performance and life cycle analysis. Further, a comprehensive catalog of ground segment functions was created.

  8. Advanced Fuel Cycles for Fusion Reactors: Passive Safety and Zero-Waste Options

    NASA Astrophysics Data System (ADS)

    Zucchetti, Massimo; Sugiyama, Linda E.

    2006-05-01

    Nuclear fusion is seen as a much ''cleaner'' energy source than fission. Most of the studies and experiments on nuclear fusion are currently devoted to the Deuterium-Tritium (DT) fuel cycle, since it is the easiest way to reach ignition. The recent stress on safety by the world's community has stimulated the research on other fuel cycles than the DT one, based on 'advanced' reactions, such as the Deuterium-Helium-3 (DHe) one. These reactions pose problems, such as the availability of 3He and the attainment of the higher plasma parameters that are required for burning. However, they have many advantages, like for instance the very low neutron activation, while it is unnecessary to breed and fuel tritium. The extrapolation of Ignitor technologies towards a larger and more powerful experiment using advanced fuel cycles (Candor) has been studied. Results show that Candor does reach the passive safety and zero-waste option. A fusion power reactor based on the DHe cycle could be the ultimate response to the environmental requirements for future nuclear power plants.

  9. The Role of Data Assimilation in the Study of Regional and Global Variability of the Hydrological Cycle

    NASA Technical Reports Server (NTRS)

    Schubert, Siegfried; Chang, Yehui; Chen, Tsing-Chang

    1999-01-01

    In the coming years, researchers will have at their disposal a host of new observations from advanced space-based sensors (e.g. the Tropical Rainfall Measuring Mission, EOS Terra and PM missions) providing, among other things, a more complete and accurate description of various components of the Earth's hydrological cycle. Also, increasingly more sophisticated and comprehensive geophysical models will provide researchers better tools for simulating the hydrological cycle, and for carrying out mechanistic studies of the role of moist processes in the climate system. In addition, new data sets generated with global four-dimensional data assimilation (4DDA) systems will provide comprehensive and complete information on both the state and forcing of the climate system. Ideally, the 4DDA systems optimally incorporate all relevant information from the observations together with a first guess from a state-of-the-art geophysical model to produce a "best" estimate of the climate state. Furthermore, to the extent that the assimilating models are realistic and are constrained by the observations, they should provide reliable estimates of the associated physical processes or climate forcing fields. While operational weather centers now have a considerable history of providing reliable estimates of the basic atmospheric state variables, the associated processes or diagnostic fields (which are less well constrained by the observations and sensitive to errors in the model's physical parameterizations) are still considered experimental and of uncertain quality. In this study we will examine the current generation of reanalysis products to assess the capabilities of 4DDA systems to represent components of the hydrological cycle. The focus is on the role of the model in providing consistent estimates of moist processes. We will also assess whether current observations provide sufficient constraints on these model- generated fields.

  10. Life-Cycle Assessment of Advanced Nutrient Removal Technologies for Wastewater Treatment.

    PubMed

    Rahman, Sheikh M; Eckelman, Matthew J; Onnis-Hayden, Annalisa; Gu, April Z

    2016-03-15

    Advanced nutrient removal processes, while improving the water quality of the receiving water body, can also produce indirect environmental and health impacts associated with increases in usage of energy, chemicals, and other material resources. The present study evaluated three levels of treatment for nutrient removal (N and P) using 27 representative treatment process configurations. Impacts were assessed across multiple environmental and health impacts using life-cycle assessment (LCA) following the Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI) impact-assessment method. Results show that advanced technologies that achieve high-level nutrient removal significantly decreased local eutrophication potential, while chemicals and electricity use for these advanced treatments, particularly multistage enhanced tertiary processes and reverse osmosis, simultaneously increased eutrophication indirectly and contributed to other potential environmental and health impacts including human and ecotoxicity, global warming potential, ozone depletion, and acidification. Average eutrophication potential can be reduced by about 70% when Level 2 (TN = 3 mg/L; TP = 0.1 mg/L) treatments are employed instead of Level 1 (TN = 8 mg/L; TP = 1 mg/L), but the implementation of more advanced tertiary processes for Level 3 (TN = 1 mg/L; TP = 0.01 mg/L) treatment may only lead to an additional 15% net reduction in life-cycle eutrophication potential. PMID:26871301

  11. Multi-objective optimization of combined Brayton and inverse Brayton cycles using advanced optimization algorithms

    NASA Astrophysics Data System (ADS)

    Venkata Rao, R.; Patel, Vivek

    2012-08-01

    This study explores the use of teaching-learning-based optimization (TLBO) and artificial bee colony (ABC) algorithms for determining the optimum operating conditions of combined Brayton and inverse Brayton cycles. Maximization of thermal efficiency and specific work of the system are considered as the objective functions and are treated simultaneously for multi-objective optimization. Upper cycle pressure ratio and bottom cycle expansion pressure of the system are considered as design variables for the multi-objective optimization. An application example is presented to demonstrate the effectiveness and accuracy of the proposed algorithms. The results of optimization using the proposed algorithms are validated by comparing with those obtained by using the genetic algorithm (GA) and particle swarm optimization (PSO) on the same example. Improvement in the results is obtained by the proposed algorithms. The results of effect of variation of the algorithm parameters on the convergence and fitness values of the objective functions are reported.

  12. Simulated and observed trends in key variables of the Arctic marine carbon cycle

    NASA Astrophysics Data System (ADS)

    Goris, Nadine; Heinze, Christoph; Lauvset, Siv; Petrenko, Dmitry; Pozdnyakov, Dmitry; Schwinger, Jörg

    2013-04-01

    For the Arctic region, a thorough monitoring of the marine carbon cycle is important, as the general "polar amplification" of climate change also translates into the biogeochemical realm. As compared to the global ocean, the sink for human-produced CO2 is fairly small in the Arctic Ocean itself. Nevertheless, it is important to follow up this Arctic sink as a further control of the regional carbon budget and to record changes in the marine carbon cycle on the way towards a "blue Arctic". Since observations on the Arctic are rare, the EU FP7 MONARCH-A project tries to enable adequate descriptions of the status and evolution of the Arctic region Earth system components by generating time series of observation datasets and model hindcasts. In terms of the marine carbon cycle, this analysis focuses mainly on the key variables pCO2 and primary productivity. For oceanic pCO2, the comprehensive data-sets SOCAT and LDEO were combined, while measurements of atmospheric CO2 were collected from the GLOBALVIEW-CO2 data integration project. Monthly Primary Production fields were retrieved from the sensors MODIS and SeaWiFs. In order to get an overall picture of the behavior and trends of those key variables, in addition the physical-biogeochemical model MICOM-HAMOCC-M was employed. The investigation showed that both oceanic and atmospheric pCO2 are consistent variables which have a regular annual cycle and a similar behaviour all over the Arctic for both model and data. In contrast, primary production shows an irregular annual cycle in both range and form, varying over the Arctic. While a few well distributed measurement stations with continuous observations are sufficient to get a comprehensive picture for consistent variables like pCO2, it is relatively difficult and costly to get a comprehensive record of non-consistent variables. Since the provided data-set for primary production covers a relatively short time-scale, it was neither possible to confidently validate the model

  13. A supersonic fan equipped variable cycle engine for a Mach 2.7 supersonic transport

    NASA Technical Reports Server (NTRS)

    Tavares, T. S.

    1985-01-01

    The concept of a variable cycle turbofan engine with an axially supersonic fan stage as powerplant for a Mach 2.7 supersonic transport was evaluated. Quantitative cycle analysis was used to assess the effects of the fan inlet and blading efficiencies on engine performance. Thrust levels predicted by cycle analysis are shown to match the thrust requirements of a representative aircraft. Fan inlet geometry is discussed and it is shown that a fixed geometry conical spike will provide sufficient airflow throughout the operating regime. The supersonic fan considered consists of a single stage comprising a rotor and stator. The concept is similar in principle to a supersonic compressor, but differs by having a stator which removes swirl from the flow without producing a net rise in static pressure. Operating conditions peculiar to the axially supersonic fan are discussed. Geometry of rotor and stator cascades are presented which utilize a supersonic vortex flow distribution. Results of a 2-D CFD flow analysis of these cascades are presented. A simple estimate of passage losses was made using empirical methods.

  14. Intercellular Variability in Protein Levels from Stochastic Expression and Noisy Cell Cycle Processes

    PubMed Central

    Soltani, Mohammad; Vargas-Garcia, Cesar A.; Antunes, Duarte; Singh, Abhyudai

    2016-01-01

    Inside individual cells, expression of genes is inherently stochastic and manifests as cell-to-cell variability or noise in protein copy numbers. Since proteins half-lives can be comparable to the cell-cycle length, randomness in cell-division times generates additional intercellular variability in protein levels. Moreover, as many mRNA/protein species are expressed at low-copy numbers, errors incurred in partitioning of molecules between two daughter cells are significant. We derive analytical formulas for the total noise in protein levels when the cell-cycle duration follows a general class of probability distributions. Using a novel hybrid approach the total noise is decomposed into components arising from i) stochastic expression; ii) partitioning errors at the time of cell division and iii) random cell-division events. These formulas reveal that random cell-division times not only generate additional extrinsic noise, but also critically affect the mean protein copy numbers and intrinsic noise components. Counter intuitively, in some parameter regimes, noise in protein levels can decrease as cell-division times become more stochastic. Computations are extended to consider genome duplication, where transcription rate is increased at a random point in the cell cycle. We systematically investigate how the timing of genome duplication influences different protein noise components. Intriguingly, results show that noise contribution from stochastic expression is minimized at an optimal genome-duplication time. Our theoretical results motivate new experimental methods for decomposing protein noise levels from synchronized and asynchronized single-cell expression data. Characterizing the contributions of individual noise mechanisms will lead to precise estimates of gene expression parameters and techniques for altering stochasticity to change phenotype of individual cells. PMID:27536771

  15. Intercellular Variability in Protein Levels from Stochastic Expression and Noisy Cell Cycle Processes.

    PubMed

    Soltani, Mohammad; Vargas-Garcia, Cesar A; Antunes, Duarte; Singh, Abhyudai

    2016-08-01

    Inside individual cells, expression of genes is inherently stochastic and manifests as cell-to-cell variability or noise in protein copy numbers. Since proteins half-lives can be comparable to the cell-cycle length, randomness in cell-division times generates additional intercellular variability in protein levels. Moreover, as many mRNA/protein species are expressed at low-copy numbers, errors incurred in partitioning of molecules between two daughter cells are significant. We derive analytical formulas for the total noise in protein levels when the cell-cycle duration follows a general class of probability distributions. Using a novel hybrid approach the total noise is decomposed into components arising from i) stochastic expression; ii) partitioning errors at the time of cell division and iii) random cell-division events. These formulas reveal that random cell-division times not only generate additional extrinsic noise, but also critically affect the mean protein copy numbers and intrinsic noise components. Counter intuitively, in some parameter regimes, noise in protein levels can decrease as cell-division times become more stochastic. Computations are extended to consider genome duplication, where transcription rate is increased at a random point in the cell cycle. We systematically investigate how the timing of genome duplication influences different protein noise components. Intriguingly, results show that noise contribution from stochastic expression is minimized at an optimal genome-duplication time. Our theoretical results motivate new experimental methods for decomposing protein noise levels from synchronized and asynchronized single-cell expression data. Characterizing the contributions of individual noise mechanisms will lead to precise estimates of gene expression parameters and techniques for altering stochasticity to change phenotype of individual cells. PMID:27536771

  16. Linking the lytic and lysogenic bacteriophage cycles to environmental conditions, host physiology and their variability in coastal lagoons.

    PubMed

    Maurice, C F; Bouvier, C; de Wit, R; Bouvier, T

    2013-09-01

    Changes in environmental conditions and prokaryote physiology can strongly affect the dynamics of both the lysogenic and lytic bacteriophage replication cycles in aquatic systems. However, it remains unclear whether it is the nature, amplitude or frequency of these changes that alter the phage replication cycles. We performed an annual survey of three Mediterranean lagoons with contrasting levels of chlorophyll a concentration and salinity to explore how these cues and their variability influence either replication cycle. The lytic cycle was always detected and showed seasonal patterns, whereas the lysogenic cycle was often undetected and highly variable. The lytic cycle was influenced by environmental and prokaryotic physiological cues, increasing with concentrations of dissolved organic carbon, chlorophyll a, and the proportion of respiring cells, and decreasing with the proportion of damaged cells. In contrast, lysogeny was not explained by the magnitude of any environmental or physiological parameter, but increased with the amplitude of change in prokaryote physiology. Our study suggests that both cycles are regulated by distinct factors: the lytic cycle is dependent on environmental parameters and host physiology, while lysogeny is dependent on the variability of prokaryote physiology. This could lead to the contrasting patterns observed between both cycles in aquatic systems. PMID:23581698

  17. The Path to Sustainable Nuclear Energy. Basic and Applied Research Opportunities for Advanced Fuel Cycles

    SciTech Connect

    Finck, P.; Edelstein, N.; Allen, T.; Burns, C.; Chadwick, M.; Corradini, M.; Dixon, D.; Goff, M.; Laidler, J.; McCarthy, K.; Moyer, B.; Nash, K.; Navrotsky, A.; Oblozinsky, P.; Pasamehmetoglu, K.; Peterson, P.; Sackett, J.; Sickafus, K. E.; Tulenko, J.; Weber, W.; Morss, L.; Henry, G.

    2005-09-01

    The objective of this report is to identify new basic science that will be the foundation for advances in nuclear fuel-cycle technology in the near term, and for changing the nature of fuel cycles and of the nuclear energy industry in the long term. The goals are to enhance the development of nuclear energy, to maximize energy production in nuclear reactor parks, and to minimize radioactive wastes, other environmental impacts, and proliferation risks. The limitations of the once-through fuel cycle can be overcome by adopting a closed fuel cycle, in which the irradiated fuel is reprocessed and its components are separated into streams that are recycled into a reactor or disposed of in appropriate waste forms. The recycled fuel is irradiated in a reactor, where certain constituents are partially transmuted into heavier isotopes via neutron capture or into lighter isotopes via fission. Fast reactors are required to complete the transmutation of long-lived isotopes. Closed fuel cycles are encompassed by the Department of Energy?s Advanced Fuel Cycle Initiative (AFCI), to which basic scientific research can contribute. Two nuclear reactor system architectures can meet the AFCI objectives: a ?single-tier? system or a ?dual-tier? system. Both begin with light water reactors and incorporate fast reactors. The ?dual-tier? systems transmute some plutonium and neptunium in light water reactors and all remaining transuranic elements (TRUs) in a closed-cycle fast reactor. Basic science initiatives are needed in two broad areas: ? Near-term impacts that can enhance the development of either ?single-tier? or ?dual-tier? AFCI systems, primarily within the next 20 years, through basic research. Examples: Dissolution of spent fuel, separations of elements for TRU recycling and transmutation Design, synthesis, and testing of inert matrix nuclear fuels and non-oxide fuels Invention and development of accurate on-line monitoring systems for chemical and nuclear species in the nuclear

  18. Variability of mesospheric water vapor above Bern in relation to the 27-day solar rotation cycle

    NASA Astrophysics Data System (ADS)

    Lainer, Martin; Hocke, Klemens; Kämpfer, Niklaus

    2016-04-01

    We investigate the solar-terrestrial response of mesospheric water vapor from a mid-latitudinal observation site at the 27-day solar rotation cycle time scale. Eight years of water vapor profile measurements above Bern (46.88°N/7.46°E) by the microwave radiometer MIAWARA are used to study prominent oscillation features. The spectral data analyses shows enhanced oscillations in the 27-day period band above 0.1hPa during the rising sunspot activity of solar cycle 24. Aura MLS observations of H2O support these results by showing a similar behavior. The relationship between mesospheric H2O and the solar Lyman-α flux (FLyα) is studied by comparing the similarity of their temporal oscillations. The H2O oscillation is negatively correlated to FLyα oscillation with a correlation coefficient of up to ‑0.3 to ‑0.4, and the phase lag is 6-10 days on 0.04hPa. The confidence level of the correlation is ≥ 99%. Additionally we compute wavelet power spectra, cross-wavelet transform and wavelet coherence (WTC). The latter shows significant (two σ level) correlations occurring intermittently in the 27 and 13-day band with variable phase lock behavior. Large FLyα oscillations appeared after the solar superstorm in July 2012 and the H2O oscillations show a well pronounced anti-correlation. The competition between advective transport and photo-dissociation loss of mesospheric H2O may explain the sometimes variable phase relationship of mesospheric H2O and FLyα oscillations. Generally, the WTC analysis indicates that solar variability causes observable photochemical and dynamical processes in the mid-latitude mesosphere.

  19. Variable stream control engine concept for advanced supersonic aircraft: Features and benefits

    NASA Technical Reports Server (NTRS)

    Howlett, R. A.

    1976-01-01

    The Variable Stream Control Engine is studied for advanced supersonic cruise aircraft. Significant environmental and performance improvements relative to first generation supersonic turbojet engines are cited. Two separate flow streams, each with independent burner and nozzle systems are incorporated within the engine. By unique control of the exhaust temperatures and velocities in two coannular streams, significant reduction in jet noise is obtained.

  20. Development and proof-testing of advanced absorption refrigeration cycle concepts

    SciTech Connect

    Modahl, R.J.; Hayes, F.C. . Applied Unitary/Refrigeration Systems Div.)

    1992-03-01

    The overall objectives of this project are to evaluate, develop, and proof-test advanced absorption refrigeration cycles that are applicable to residential and commercial heat pumps for space conditioning. The heat pump system is to be direct-fired with natural gas and is to use absorption working fluids whose properties are known. Target coefficients of performance (COPs) are 1.6 at 47{degrees}F and 1.2 at 17{degrees} in the heating mode, and 0.7 at 95{degree}F in the cooling mode, including the effect of flue losses. The project is divided into three phases. Phase I entailed the analytical evaluation of advanced cycles and included the selection of preferred concepts for further development. Phase II involves the development and testing of critical components and of a complete laboratory breadboard version of the selected system. Phase III calls for the development of a prototype unit and is contingent on the successful completion of Phase II. This report covers Phase I work on the project. In Phase 1, 24 advanced absorption cycle/fluid combinations were evaluated, and computer models were developed to predict system performance. COP, theoretical pump power, and internal heat exchange were calculated for each system, and these calculations were used as indicators of operating and installed costs in order to rank the relative promise of each system. The highest ranking systems involve the cycle concept of absorber/generator heat exchange, generator heat exchanger/absorber heat exchange, regeneration, and resorption/desorption, in combination with the NH{sub 3}/H{sub 2}O/LiBr ternary absorption fluid mixture or with the NH{sub 3}/H{sub 2}O binary solution. Based upon these conclusions, the recommendation was made to proceed to Phase II, the laboratory breadboard proof-of- concept.

  1. Seasonal cycles and variability of O3 and H2O in the UT/LMS during SPURT

    NASA Astrophysics Data System (ADS)

    Krebsbach, M.; Schiller, C.; Brunner, D.; Günther, G.; Hegglin, M. I.; Mottaghy, D.; Riese, M.; Spelten, N.; Wernli, H.

    2005-08-01

    Airborne high resolution in situ measurements of a large set of trace gases including ozone (O3) and total water (H2O) in the upper troposphere and the lowermost stratosphere (UT/LMS) have been performed above Europe within the SPURT project. With its innovative campaign concept, SPURT provides an extensive data coverage of the UT/LMS in each season within the time period between November 2001 and July 2003. Ozone volume mixing ratios in the LMS show a distinct spring maximum and autumn minimum, whereas the O3 seasonal cycle in the UT is shifted by 2 to 3 month later towards the end of the year. The more variable H2O measurements reveal a maximum during spring/summer and a minimum during autumn/winter with no phase shift between the two atmospheric compartments. For a comprehensive insight into trace gas composition and variability in the UT/LMS several statistical methods are applied using chemical, thermal and dynamical vertical coordinates. In particular, 2-dimensional probability distribution functions serve as a tool to transform localised aircraft data to a more comprehensive view of the probed atmospheric region. It appears that both trace gases, O3 and H2O, reveal the most compact arrangement and are best correlated in the view of potential vorticity (PV) and distance to the local tropopause, indicating an advanced mixing state on these surfaces. Thus, strong gradients of PV seem to act as a transport barrier both in the vertical and the horizontal direction. The alignment of trace gas isopleths reflects the existence of a year-round extra-tropical tropopause transition layer. The SPURT measurements reveal that this layer is mainly affected by stratospheric air during winter/spring and by tropospheric air during autumn/summer. Mixing entropy values for O3 and H2O in the LMS appear to be maximal during spring and summer, respectively, indicating highest variability of these trace gases during the respective seasons.

  2. Solar cycles or random processes? Evaluating solar variability in Holocene climate records.

    PubMed

    Turner, T Edward; Swindles, Graeme T; Charman, Dan J; Langdon, Peter G; Morris, Paul J; Booth, Robert K; Parry, Lauren E; Nichols, Jonathan E

    2016-01-01

    Many studies have reported evidence for solar-forcing of Holocene climate change across a range of archives. These studies have compared proxy-climate data with records of solar variability (e.g. (14)C or (10)Be), or have used time series analysis to test for the presence of solar-type cycles. This has led to some climate sceptics misrepresenting this literature to argue strongly that solar variability drove the rapid global temperature increase of the twentieth century. As proxy records underpin our understanding of the long-term processes governing climate, they need to be evaluated thoroughly. The peatland archive has become a prominent line of evidence for solar forcing of climate. Here we examine high-resolution peatland proxy climate data to determine whether solar signals are present. We find a wide range of significant periodicities similar to those in records of solar variability: periods between 40-100 years, and 120-140 years are particularly common. However, periodicities similar to those in the data are commonly found in random-walk simulations. Our results demonstrate that solar-type signals can be the product of random variations alone, and that a more critical approach is required for their robust interpretation. PMID:27045989

  3. Time variability in the annual cycle of sea ice thickness in the Transpolar Drift

    NASA Astrophysics Data System (ADS)

    Hansen, E.; Gerland, S.; Høyland, K. V.; Pavlova, O.; Spreen, G.

    2015-12-01

    The annual cycle of modal and mean sea ice thickness was derived from upward looking sonar ice thickness observations (1990-2011) in Fram Strait. The average annual peak-to-trough amplitude of the mode of 0.54 m is superimposed on interannual variability with peak-to-trough amplitudes of 0.73 m on time scales of 6-8 years, which again is superimposed on a long-term trend of -0.55 m/decade over the observation period. The long-term trend is stronger for April than for August, the average months of maximum and minimum modal thickness. As a result, the annual peak-to-trough modal thickness amplitude was reduced by 30% between the 1990s and the 2000s. The average annual peak-to-trough amplitude of the mean ice thickness of 1.20 m is also superimposed on interannual variability, with as much as 0.97 m thickness change over only 3 years. These two modes of variability are superimposed on a long-term trend of -0.35 m/decade through the entire data set. In contrast to the modal thickness, the long-term trend is weaker for the average month of maximum mean thickness (June), than for the average month of minimum (September). Therefore, the annual peak-to-trough amplitude of the mean ice thickness increased by 14% between the 1990s and the 2000s.

  4. Solar cycles or random processes? Evaluating solar variability in Holocene climate records

    PubMed Central

    Turner, T. Edward; Swindles, Graeme T.; Charman, Dan J.; Langdon, Peter G.; Morris, Paul J.; Booth, Robert K.; Parry, Lauren E.; Nichols, Jonathan E.

    2016-01-01

    Many studies have reported evidence for solar-forcing of Holocene climate change across a range of archives. These studies have compared proxy-climate data with records of solar variability (e.g. 14C or 10Be), or have used time series analysis to test for the presence of solar-type cycles. This has led to some climate sceptics misrepresenting this literature to argue strongly that solar variability drove the rapid global temperature increase of the twentieth century. As proxy records underpin our understanding of the long-term processes governing climate, they need to be evaluated thoroughly. The peatland archive has become a prominent line of evidence for solar forcing of climate. Here we examine high-resolution peatland proxy climate data to determine whether solar signals are present. We find a wide range of significant periodicities similar to those in records of solar variability: periods between 40–100 years, and 120–140 years are particularly common. However, periodicities similar to those in the data are commonly found in random-walk simulations. Our results demonstrate that solar-type signals can be the product of random variations alone, and that a more critical approach is required for their robust interpretation. PMID:27045989

  5. Variability of oceanic carbon cycle in the North Pacific from seasonal to decadal scales

    NASA Astrophysics Data System (ADS)

    Xiu, Peng; Chai, Fei

    2014-08-01

    Variability of upper-ocean carbon cycle in the North Pacific during 1958-2010 period is investigated using a physical-biogeochemical model. Comparisons with in situ data from five different oceanographic environments in the South China Sea, Monterey Bay, North Pacific gyre, northwestern Pacific, and Gulf of Alaska indicate that the model usually captures observed seasonal and interannual variability in both sea surface pCO2 and sea-air CO2 flux. Seasonal variability of pCO2 and CO2 flux in the North Pacific follows the change in sea surface temperature (SST) closely with high and low values in summer and winter, respectively. Total CO2 modifies pCO2 seasonal pattern in an opposite manner with respect to SST, and surface wind speed modifies the magnitude of CO2 flux variations. On interannual and decadal time scales, sea surface pCO2 is primarily controlled by anthropogenic CO2, followed by modulations by the El Niño-Southern Oscillation and the Pacific Decadal Oscillation (PDO), while sea-air CO2 flux is significantly regulated by the PDO and the North Pacific Gyre Oscillation (NPGO). We show that anthropogenic CO2 tends to amplify the influence on CO2 flux from the PDO but to damp the influence from the NPGO.

  6. The effect of time trial cycling position on physiological and aerodynamic variables.

    PubMed

    Fintelman, D M; Sterling, M; Hemida, H; Li, F-X

    2015-01-01

    To reduce aerodynamic resistance cyclists lower their torso angle, concurrently reducing Peak Power Output (PPO). However, realistic torso angle changes in the range used by time trial cyclists have not yet been examined. Therefore the aim of this study was to investigate the effect of torso angle on physiological parameters and frontal area in different commonly used time trial positions. Nineteen well-trained male cyclists performed incremental tests on a cycle ergometer at five different torso angles: their preferred torso angle and at 0, 8, 16 and 24°. Oxygen uptake, carbon dioxide expiration, minute ventilation, gross efficiency, PPO, heart rate, cadence and frontal area were recorded. The frontal area provides an estimate of the aerodynamic drag. Overall, results showed that lower torso angles attenuated performance. Maximal values of all variables, attained in the incremental test, decreased with lower torso angles (P < 0.001). The 0° torso angle position significantly affected the metabolic and physiological variables compared to all other investigated positions. At constant submaximal intensities of 60, 70 and 80% PPO, all variables significantly increased with increasing intensity (P < 0.0001) and decreasing torso angle (P < 0.005). This study shows that for trained cyclists there should be a trade-off between the aerodynamic drag and physiological functioning. PMID:25658151

  7. EXPERIMENTAL AND THEORETICAL INVESTIGATIONS OF NEW POWER CYCLES AND ADVANCED FALLING FILM HEAT EXCHANGERS

    SciTech Connect

    Arsalan Razani; Kwang J. Kim

    2000-10-28

    The annual progress report for the period of October 1, 1999 to September 30, 2000 on DOE/UNM grant number DE-FG26-98FT40148 discusses the progress on both the theoretical analysis of advanced power cycles and the experimental investigation of advanced falling film heat exchangers. The previously developed computer program for the triple cycle, based on the air standard cycle assumption, was modified to include actual air composition (%77.48 N{sub 2}, %20.59 O{sub 2}, %1.9 H{sub 2}O, and %0.03 CO{sub 2}). The actual combustion products were used in exergy analysis of the triple cycle. The effect of steam injection into the combustion chamber on its irreversibility, and the irreversibility of the entire cycle, was evaluated. A more practical fuel inlet condition and a better position of the feedwater heater in the steam cycle were used in the modified cycle. The effect of pinch point and the temperature difference between the combustion products, as well as the steam in the heat recovery steam generator on irreversibility of the cycle were evaluated. Design, construction, and testing of the multitube horizontal falling film condenser facility were completed. Two effective heat transfer additives (2-ethyl-1-hexanol and alkyl amine) were identified and tested for steam condensation. The test results are included. The condenser was designed with twelve tubes in an array of three horizontals and four verticals, with a 2-inch horizontal and 1.5-inch vertical in-line pitch. By using effective additives, the condensation heat transfer rate can be augmented as much as 30%, as compared to a heat transfer that operated without additives under the same operating condition. When heat transfer additives function effectively, the condensate-droplets become more dispersed and have a smaller shape than those produced without additives. These droplets, unlike traditional turbulence, start at the top portion of the condenser tubes and cover most of the tubes. Such a flow behavior can

  8. Advances in Understanding Global Water Cycle with Advent of Global Precipitation Measurement (GPM) Mission

    NASA Technical Reports Server (NTRS)

    Smith, Eric A.; Starr, David (Technical Monitor)

    2002-01-01

    Within this decade the internationally organized Global Precipitation Measurement (GPM) Mission will take an important step in creating a global precipitation observing system from space. One perspective for understanding the nature of GPM is that it will be a hierarchical system of datastreams beginning with very high caliber combined dual frequency radar/passive microwave (PMW) rain-radiometer retrievals, to high caliber PMW rain-radiometer only retrievals, and then on to blends of the former datastreams with additional lower-caliber PMW-based and IR-based rain retrievals. Within the context of the now emerging global water & energy cycle (GWEC) programs of a number of research agencies throughout the world, GPM serves as a centerpiece space mission for improving our understanding of the global water cycle from a global measurement perspective. One of the salient problems within our current understanding of the global water and energy cycle is determining whether a change in the rate of the water cycle is accompanying changes in climate, e.g., climate warming. As there are a number of ways in which to define a rate-change of the global water cycle, it is not entirely clear as to what constitutes such a determination. This paper presents an overview of the GPM Mission and how its observations can be used within the framework of the oceanic and continental water budget equations to determine whether a given perturbation in precipitation is indicative of an actual rate change in the global water cycle, consistent with required responses in water storage and/or water flux transport processes, or whether it is the natural variability of a fixed rate cycle.

  9. Advances In Understanding Global Water Cycle With Advent of GPM Mission

    NASA Technical Reports Server (NTRS)

    Smith, Eric A.

    2002-01-01

    variability of a fixed rate cycle.

  10. Advanced Fuel Cycle Initiative (AFCI) Repository Impact Evaluation FY-05 Progress Report

    SciTech Connect

    Halsey, W G

    2005-09-12

    An important long-term objective of advanced nuclear fuel cycle (AFC) technologies is to provide improvement in the long-term management of radioactive waste. Compared to a once-thru fuel cycle, it is possible to generate far less waste, and potentially easier waste to manage, with advanced fuel cycles. However, the precise extent and value of these benefits are complex and difficult to quantify. This document presents a status report of efforts within AFCI Systems Analysis to define and quantify the AFC benefits to geologic disposal, development of cooperative efforts with the US repository program, and participation with international evaluations of AFC impacts on waste management. The primary analysis of repository benefits is conducted by ANL. This year repository impact evaluations have included: (1) Continued evaluation of LWR recycle benefits in support of scenario analysis. (2) Extension of repository analyses to consider long-term dose reductions. (3) Developing the opportunity for cooperation with the U.S. repository program. (4) International cooperation with OECD-NEA.

  11. Climate variability related to the 11 year solar cycle as represented in different spectral solar irradiance reconstructions

    NASA Astrophysics Data System (ADS)

    Kruschke, Tim; Kunze, Markus; Misios, Stergios; Matthes, Katja; Langematz, Ulrike; Tourpali, Kleareti

    2016-04-01

    Advanced spectral solar irradiance (SSI) reconstructions differ significantly from each other in terms of the mean solar spectrum, that is the spectral distribution of energy, and solar cycle variability. Largest uncertainties - relative to mean irradiance - are found for the ultraviolet range of the spectrum, a spectral region highly important for radiative heating and chemistry in the stratosphere and troposphere. This study systematically analyzes the effects of employing different SSI reconstructions in long-term (40 years) chemistry-climate model (CCM) simulations to estimate related uncertainties of the atmospheric response. These analyses are highly relevant for the next round of CCM studies as well as climate models within the CMIP6 exercise. The simulations are conducted by means of two state-of-the-art CCMs - CESM1(WACCM) and EMAC - run in "atmosphere-only"-mode. These models are quite different with respect to the complexity of the implemented radiation and chemistry schemes. CESM1(WACCM) features a chemistry module with considerably higher spectral resolution of the photolysis scheme while EMAC employs a radiation code with notably higher spectral resolution. For all simulations, concentrations of greenhouse gases and ozone depleting substances, as well as observed sea surface temperatures (SST) are set to average conditions representative for the year 2000 (for SSTs: mean of decade centered over year 2000) to exclude anthropogenic influences and differences due to variable SST forcing. Only the SSI forcing differs for the various simulations. Four different forcing datasets are used: NRLSSI1 (used as a reference in all previous climate modeling intercomparisons, i.e. CMIP5, CCMVal, CCMI), NRLSSI2, SATIRE-S, and the SSI forcing dataset recommended for the CMIP6 exercise. For each dataset, a solar maximum and minimum timeslice is integrated, respectively. The results of these simulations - eight in total - are compared to each other with respect to their

  12. Effect of LEO cycling on 125 Ah advanced design IPV nickel-hydrogen battery cells

    NASA Technical Reports Server (NTRS)

    Smithrick, John J.; Hall, Stephen W.

    1990-01-01

    An advanced 125 Ah individual pressure vessel (IPV) nickel-hydrogen cell was designed. The primary function of the advanced cell is to store and deliver energy for long-term, low earth-orbit (LEO) spacecraft missions. The new features of this design are: (1) use of 26 percent rather than 31 percent potassium hydroxide (KOH) electrolyte, (2) use of a patented catalyzed wall wick, (3) use of serrated-edge separators to facilitate gaseous oxygen and hydrogen flow within the cell, while still maintaining physical contact with the wall wick for electrolyte management, and (4) use of a floating rather than a fixed stack (state-of-the-art) to accommodate nickel electrode expansion. Six 125-Ah flight cells based on this design were fabricated by Eagle-Picher. Three of the cells contain all of the advanced features (test cells) and three are the same as the test cells except they don't have catalyst on the wall wick (control cells). All six cells are in the process of being evaluated in a LEO cycle life test. The cells have accumulated about 4700 LEO cycles (60 percent DOD 10 C). There have been no cell failures; the catalyzed wall wick cells, however, are performing better.

  13. Effect of LEO cycling on 125 Ah advanced design IPV nickel-hydrogen battery cells

    NASA Technical Reports Server (NTRS)

    Smithrick, John J.; Hall, Stephen W.

    1990-01-01

    An advanced 125 Ah individual pressure vessel (IPV) nickel-hydrogen cell was designed. The primary function of the advanced cell, is to store and deliver energy for long term, low earth-orbit (LEO) spacecraft missions. The new features of this design are: (1) use of 26 percent rather than 31 percent potassium hydroxide (KOH) electrolyte, (2) use of a patented catalyzed wall wick, (3) use of serrated edge separators to facilitate gaseous oxygen and hydrogen flow within the cell, while still maintaining physical contact with the wall wick for electrolyte management, and (4) use of a floating rather than a fixed stack (state-of-the-art) to accommodate nickel electrode expansion. Six 125 Ah flight cells based on this design were fabricated by Eagle-Picher. Three of the cells contain all of the advanced features (test cells) and three are the same as the test cells except they don't have catalyst on the wall wick (control cells). All six cells are in the process of being evaluated in a LEO cycle life test. The cells have accumulated about 4700 LEO cycles (60 percent DOD 10 C). There have been no cell failures, the catalyzed wall wick cells however, are performing better.

  14. Solar cycle variation of the statistical distribution of the solar wind ɛ parameter and its constituent variables

    NASA Astrophysics Data System (ADS)

    Tindale, E.; Chapman, S. C.

    2016-06-01

    We use 20 years of Wind solar wind observations to investigate the solar cycle variation of the solar wind driving of the magnetosphere. For the first time, we use generalized quantile-quantile plots to compare the statistical distribution of four commonly used solar wind coupling parameters, Poynting flux, B2, the ɛ parameter, and vB, between the maxima and minima of solar cycles 23 and 24. We find the distribution is multicomponent and has the same functional form at all solar cycle phases; the change in distribution is captured by a simple transformation of variables for each component. The ɛ parameter is less sensitive than its constituent variables to changes in the distribution of extreme values between successive solar maxima. The quiet minimum of cycle 23 manifests only in lower extreme values, while cycle 24 was less active across the full distribution range.

  15. Badhwar-O'Neil 2007 Galactic Cosmic Ray (GCR) Model Using Advanced Composition Explorer (ACE) Measurements for Solar Cycle 23

    NASA Technical Reports Server (NTRS)

    ONeill, P. M.

    2007-01-01

    Advanced Composition Explorer (ACE) satellite measurements of the galactic cosmic ray flux and correlation with the Climax Neutron Monitor count over Solar Cycle 23 are used to update the Badhwar O'Neill Galactic Cosmic Ray (GCR) model.

  16. Stage-by-Stage and Parallel Flow Path Compressor Modeling for a Variable Cycle Engine

    NASA Technical Reports Server (NTRS)

    Kopasakis, George; Connolly, Joseph W.; Cheng, Larry

    2015-01-01

    This paper covers the development of stage-by-stage and parallel flow path compressor modeling approaches for a Variable Cycle Engine. The stage-by-stage compressor modeling approach is an extension of a technique for lumped volume dynamics and performance characteristic modeling. It was developed to improve the accuracy of axial compressor dynamics over lumped volume dynamics modeling. The stage-by-stage compressor model presented here is formulated into a parallel flow path model that includes both axial and rotational dynamics. This is done to enable the study of compressor and propulsion system dynamic performance under flow distortion conditions. The approaches utilized here are generic and should be applicable for the modeling of any axial flow compressor design.

  17. Premix fuels study applicable to duct burner conditions for a variable cycle engine

    NASA Technical Reports Server (NTRS)

    Venkataramani, K. S.

    1978-01-01

    Emission levels and performance of a premixing Jet-A/air duct burner were measured at reference conditions representative of take-off and cruise for a variable cycle engine. In a parametric variation sequence of tests, data were obtained at inlet temperatures of 400, 500 and 600K at equivalence ratios varying from 0.9 to the lean stability limit. Ignition was achieved at all the reference conditions although the CO levels were very high. Significant nonuniformity across the combustor was observed for the emissions at the take-off condition. At a reference Mach number of 0.117 and an inlet temperature of 600K, corresponding to a simulated cruise condition, the NOx emission level was approximately 1 gm/kg-fuel.

  18. Experimental Evaluation of a Low Emissions High Performance Duct Burner for Variable Cycle Engines (VCE)

    NASA Technical Reports Server (NTRS)

    Lohmann, R. P.; Mador, R. J.

    1979-01-01

    An evaluation was conducted with a three stage Vorbix duct burner to determine the performance and emissions characteristics of the concept and to refine the configuration to provide acceptable durability and operational characteristics for its use in the variable cycle engine (VCE) testbed program. The tests were conducted at representative takeoff, transonic climb, and supersonic cruise inlet conditions for the VSCE-502B study engine. The test stand, the emissions sampling and analysis equipment, and the supporting flow visualization rigs are described. The performance parameters including the fuel-air ratio, the combustion efficiency/exit temperature, thrust efficiency, and gaseous emissions calculations are defined. The test procedures are reviewed and the results are discussed.

  19. Definition study for variable cycle engine testbed engine and associated test program

    NASA Technical Reports Server (NTRS)

    Vdoviak, J. W.

    1978-01-01

    The product/study double bypass variable cycle engine (VCE) was updated to incorporate recent improvements. The effect of these improvements on mission range and noise levels was determined. This engine design was then compared with current existing high-technology core engines in order to define a subscale testbed configuration that simulated many of the critical technology features of the product/study VCE. Detailed preliminary program plans were then developed for the design, fabrication, and static test of the selected testbed engine configuration. These plans included estimated costs and schedules for the detail design, fabrication and test of the testbed engine and the definition of a test program, test plan, schedule, instrumentation, and test stand requirements.

  20. Diagnosis of Thermal Efficiency of Advanced Combined Cycle Power Plants Using Optical Torque Sensors

    NASA Astrophysics Data System (ADS)

    Umezawa, Shuichi

    A new optical torque measurement method was applied to diagnosis of thermal efficiency of advanced combined cycle, i.e. ACC, plants. Since the ACC power plant comprises a steam turbine and a gas turbine and both of them are connected to the same generator, it is difficult to identify which turbine in the plant deteriorates the performance when the plant efficiency is reduced. The sensor measures axial distortion caused by power transmission by use of He-Ne laser beams, small stainless steel reflectors having bar-code patterns, and a technique of signal processing featuring high frequency. The sensor was applied to the ACC plants of TOKYO ELECTRIC POWER COMPANY, TEPCO, following the success in the application to the early combined cycle plants of TEPCO. The sensor performance was inspected over a year. After an improvement related to the signal process, it is considered that the sensor performance has reached a practical use level.

  1. Fuel-cycle greenhouse gas emissions impacts of alternative transportation fuels and advanced vehicle technologies.

    SciTech Connect

    Wang, M. Q.

    1998-12-16

    At an international conference on global warming, held in Kyoto, Japan, in December 1997, the United States committed to reduce its greenhouse gas (GHG) emissions by 7% over its 1990 level by the year 2012. To help achieve that goal, transportation GHG emissions need to be reduced. Using Argonne's fuel-cycle model, I estimated GHG emissions reduction potentials of various near- and long-term transportation technologies. The estimated per-mile GHG emissions results show that alternative transportation fuels and advanced vehicle technologies can help significantly reduce transportation GHG emissions. Of the near-term technologies evaluated in this study, electric vehicles; hybrid electric vehicles; compression-ignition, direct-injection vehicles; and E85 flexible fuel vehicles can reduce fuel-cycle GHG emissions by more than 25%, on the fuel-cycle basis. Electric vehicles powered by electricity generated primarily from nuclear and renewable sources can reduce GHG emissions by 80%. Other alternative fuels, such as compressed natural gas and liquefied petroleum gas, offer limited, but positive, GHG emission reduction benefits. Among the long-term technologies evaluated in this study, conventional spark ignition and compression ignition engines powered by alternative fuels and gasoline- and diesel-powered advanced vehicles can reduce GHG emissions by 10% to 30%. Ethanol dedicated vehicles, electric vehicles, hybrid electric vehicles, and fuel-cell vehicles can reduce GHG emissions by over 40%. Spark ignition engines and fuel-cell vehicles powered by cellulosic ethanol and solar hydrogen (for fuel-cell vehicles only) can reduce GHG emissions by over 80%. In conclusion, both near- and long-term alternative fuels and advanced transportation technologies can play a role in reducing the United States GHG emissions.

  2. Seasonal and solar cycle variability in F-region vertical plasma drifts over Ouagadougou

    NASA Astrophysics Data System (ADS)

    Oyekola, O. S.; Ojo, Akin; Akinrimisi, J.; dePaula, E. R.

    2007-12-01

    F-region vertical drifts were made using ionosonde for the Africa equatorial station Ouagadougou (12°N, 1.5°W 5.9°N dip) from 3 a of data during January 1987 to December 1989 for solar cycle minimum, medium, and maximum conditions (F10.7 = 85, 141, and 214, respectively) under geomagnetic quiet-time. The variations are found to be dominated by the characteristics morning peak and evening prereversal enhancement (PRE) velocities. Seasonal and solar cycle effects are prominent near the dusk sector with an increase of PRE from solar minimum to maximum. The average equinoctial evening prereversal enhancement increases by almost a factor of three from low to high flux. On the average, the values of daytime and nighttime ionosonde-derived vertical drifts are smaller by about a factor of four than the magnitude often mentioned in publication for equatorial regions from other experimental techniques. In addition, the morning peak velocities maximize between about 0830-0930 LT with typical values of 12-18 m/s. In contrast, PRE have largest amplitude between about 1700-2200 LT with typical values of 5-10 m/s. The morning reversal times do not reveal any dependence on season and solar cycle; but the most probable time of occurrence is around 0530 LT. The evening reversal times are in excellent agreements for the three levels of solar activity periods apart from June solstice that exhibit considerable variations. The most likely time of occurrence is near 2000 LT. Of importance, the link between the onset / inhibition parameters of postsunset irregularities over Ouagadougou indicate anti-correlations with solar variability.

  3. Recent Advances in SRS on Hydrogen Isotope Separation Using Thermal Cycling Absorption Process

    DOE PAGESBeta

    Xiao, Xin; Sessions, Henry T.; Heung, L. Kit

    2015-02-01

    The recent Thermal Cycling Absorption Process (TCAP) advances at Savannah River Site (SRS) include compressor-free concept for heating/cooling, push and pull separation using an active inverse column, and compact column design. The new developments allow significantly higher throughput and better reliability from 1/10th of the current production system’s footprint while consuming 60% less energy. Various versions are derived in the meantime for external customers to be used in fusion energy projects and medical isotope production.

  4. A study of engine variable geometry systems for an advanced high subsonic long range commercial aircraft

    NASA Technical Reports Server (NTRS)

    Compagnon, M. A.

    1973-01-01

    Several variable geometry high Mach inlet concepts, aimed at meeting a system noise objective of 15 EPNdB below FAR part 36, for a long range, Mach 0.9 advanced commercial transport are assessed and compared to a fixed geometry inlet with multiple splitters. The effects of a variable exhaust nozzle (mixed exhaust engine) on noise, inlet geometry requirements, and economics are also presented. The best variable geometry inlet configuration identified is a variable cowl design which relies on a high throat Mach number for additional inlet noise suppression only at takeoff, and depends entirely on inlet wall treatment for noise suppression at approach power. Relative economic penalties as a function of noise level are also presented.

  5. Long-term efficacy of intensive cycle ergometer exercise training program for advanced COPD patients

    PubMed Central

    Pothirat, Chaicharn; Chaiwong, Warawut; Phetsuk, Nittaya; Liwsrisakun, Chalerm; Bumroongkit, Chaiwat; Deesomchok, Athavudh; Theerakittikul, Theerakorn; Limsukon, Atikun

    2015-01-01

    Background Exercise training has been incorporated into the international guidelines for the treatment of chronic obstructive pulmonary disease (COPD). However, the long-term efficacy of the training program for patients with advanced COPD has never been evaluated in Thailand. Purpose To determine the long-term efficacy of intensive cycle ergometer exercise program on various clinical parameters of patients with advanced COPD. Materials and methods The patients with advanced COPD were separated into two groups: the intensive ergometer exercise program group and the control group. The clinical parameters of all the patients were assessed at baseline, every month for the first 3 months, and then every 3 months until they had completed the 24-month follow-up. Mann–Whitney U test was used to compare baseline mean differences between the groups. Repeated measure analysis was applied to determine the progress in all parameters during the entire follow-up period. Mean incase imputation method was applied to estimate the parameters of dropout cases. Results A total of 41 patients were enrolled: 27 in the intensive ergometer exercise program group and 14 in the control group. The intensive cycle ergometer exercise program group showed statistically significant improvements in muscle strength (from month 1 till the end of the study, month 24), endurance time (from month 1 till the end of measurement, month 12) and clinically significant improvements in 6-minute walk distance (from month 2 until month 9), dyspnea severity by transitional dyspnea index (from month 1 till the end of the study, month 24), and quality of life (from month 1 till the end of the study, month 24). There was no significant difference in survival rates between the groups. Conclusion The intensive ergometer exercise training program revealed meaningful long-term improvements in various clinical parameters for up to 2 years. These promising results should encourage health care professionals to promote

  6. Integrated safeguards testing laboratories in support of the advanced fuel cycle initiative

    SciTech Connect

    Santi, Peter A; Demuth, Scott F; Klasky, Kristen L; Lee, Haeok; Miller, Michael C; Sprinkle, James K; Tobin, Stephen J; Williams, Bradley

    2009-01-01

    A key enabler for advanced fuel cycle safeguards research and technology development for programs such as the Advanced Fuel Cycle Initiative (AFCI) is access to facilities and nuclear materials. This access is necessary in many cases in order to ensure that advanced safeguards techniques and technologies meet the measurement needs for which they were designed. One such crucial facility is a hot cell based laboratory which would allow developers from universities, national laboratories, and commercial companies to perform iterative research and development of advanced safeguards instrumentation under realistic operating conditions but not be subject to production schedule limitations. The need for such a facility arises from the requirement to accurately measure minor actinide and/or fission product bearing nuclear materials that cannot be adequately shielded in glove boxes. With the contraction of the DOE nuclear complex following the end of the cold war, many suitable facilities at DOE sites are increasingly costly to operate and are being evaluated for closure. A hot cell based laboratory that allowed developers to install and remove instrumentation from the hot cell would allow for both risk mitigation and performance optimization of the instrumentation prior to fielding equipment in facilities where maintenance and repair of the instrumentation is difficult or impossible. These benefits are accomplished by providing developers the opportunity to iterate between testing the performance of the instrumentation by measuring realistic types and amounts of nuclear material, and adjusting and refining the instrumentation based on the results of these measurements. In this paper, we review the requirements for such a facility using the Wing 9 hot cells in the Los Alamos National Laboratory's Chemistry and Metallurgy Research facility as a model for such a facility and describe recent use of these hot cells in support of AFCI.

  7. Hot carbon corona in Mars' upper thermosphere and exosphere: 2. Solar cycle and seasonal variability

    NASA Astrophysics Data System (ADS)

    Lee, Yuni; Combi, Michael R.; Tenishev, Valeriy; Bougher, Stephen W.

    2014-12-01

    This work presents the variability over seasons (i.e., orbital position) and solar cycle of the Martian upper atmosphere and hot carbon corona. We investigate the production and distribution of energetic carbon atoms and the impacts on the total global hot carbon loss from dominant photochemical processes at five different cases: AL (aphelion and low solar activity), EL (equinox and low solar activity), EH (equinox and high solar activity), PL (perihelion and low solar activity), and PH (perihelion and high solar activity). We compare our results with previously published results but only on the limited cases due to the dearth of studies on solar EUV flux and seasonal variabilities. Photodissociation of CO and dissociative recombination of CO+ are generally regarded as the two most important source reactions for the production of hot atomic carbon. Of these two, photodissociation of CO is found to be the dominant source in all cases considered. To describe self-consistently the exosphere and the upper thermosphere, a 3-D kinetic particle simulator, the Adaptive Mesh Particle Simulator, and the 3-D Mars Thermosphere General Circulation Model are one-way coupled. The basic description of this hot carbon calculation can be found in the companion paper to this one. The spatial distributions and profiles of density and temperature and atmospheric loss rates are discussed for the cases considered. Finally, our computed global escape rate of hot carbon ranges from 5.28 × 1023 s-1 (AL) to 55.1 × 1023 s-1 (PL).

  8. Satellite-based Dust Source Identification over North Africa: Diurnal Cycle, Meteorological Controls, and Interannual Variability

    NASA Astrophysics Data System (ADS)

    Schepanski, Kerstin; Tegen, Ina; Macke, Andreas

    2010-05-01

    Mineral dust aerosol emitted from arid and semi-arid areas impacts on the weather and climate system by affecting e.g. radiation fluxes and nutrient cycles. To estimate the effect of dust aerosol, detailed knowledge on the spatio-temporal distribution of active dust sources is necessary. For a better representation of dust-related processes in numerical models and climate change projections the knowledge on the natural variability of dust source activity has to be improved. As dust sources are mostly located over remote areas satellite observations are suitable for identifying active dust sources. The accuracy of dust source identification using such an indirect method is limited by the temporal resolution and the ambiguities of the retrieval. Here, a data set on the spatial (1°x1°) and temporal (3-hourly) distribution of dust source activations (DSA) over North Africa is compiled by analyzing 15-minute Meteosat Second Generation (MSG) infra-red (IR) dust index images since March 2006. The index is designed using radiances measured by the Spinning Enhanced Visible and Infra-Red Imager (SEVIRI) on-board MSG at 8.7 µm, 10.8 µm and 12.0 µm which are converted to brightness temperatures (BTs). To strengthen the dust signal, differences of BTs are used to compute RGB-composite images. This newly data set providing information on the diurnal cycle of dust emission has been used (1) to identify most active dust source areas, and (2) to investigate on the temporal distribution of DSAs. Over the Sahara Desert 65% of dust sources become active during 06-09 UTC pointing towards an important role of the break-down of the nocturnal low-level jet (LLJ) for dust mobilization besides other meteorological features like density currents, haboobs, and cyclones. Furthermore the role of the nocturnal LLJs for dust mobilization over the Sahara is investigated by weather observations and a regional modeling study. Four years of DSA observations indicate an interannual variability in

  9. The Hydroclimate of East Africa: Seasonal cycle, Decadal Variability, and Human-induced Climate Change

    NASA Astrophysics Data System (ADS)

    Yang, Wenchang

    The hydroclimate of East Africa shows distinctive variabilities on seasonal to decadal time scales and poses a great challenge to climatologists attempting to project its response to anthropogenic emissions of greenhouse gases (GHGs). Increased frequency and intensity of droughts over East Africa in recent decades raise the question of whether the drying trend will continue into the future. To address this question, we first examine the decadal variability of the East African rainfall during March--May (MAM, the major rainy season in East Africa) and assess how well a series of models simulate the observed features. Observational results show that the drying trend during MAM is associated with decadal natural variability of sea surface temperature (SST) variations over the Pacific Ocean. The multimodel mean of the SST-forced, Coupled Model Intercomparison Project Phase 5 (CMIP5) AMIP experiment models reproduces both the climatological annual cycle and the drying trend in recent decades. The fully coupled models from the CMIP5 historical experiment, however, have systematic errors in simulating the East African rainfall annual cycle by underestimating the MAM rainfall while overestimating the October--December (OND, the second rainy season in East Africa) rainfall. The multimodel mean of the historical coupled runs of the MAM rainfall anomalies, which is the best estimate of the radiatively-forced change, shows a weak wetting trend associated with anthropogenic forcing. However, the SST anomaly pattern associated with the MAM rainfall has large discrepancies with the observations. The errors in simulating the East African hydroclimate with coupled models raise questions about how reliable model projections of future East African climate are. This motivates a fundamental study of why East African climate is the way it is and why coupled models get it wrong. East African hydroclimate is characterized by a dry annual mean climatology compared to other deep tropical

  10. CA125-related tumor cell kinetics variables after chemotherapy in advanced ovarian cancer: a systematic review.

    PubMed

    Colloca, G; Venturino, A; Governato, I

    2016-08-01

    Various kinetic parameters, based on a minimum of two time points, have been built with CA125 determinations. The aim of this study is to review studies about the clinical application of CA125-related tumor cell kinetics variables in patients with advanced ovarian cancer (AOC) receiving chemotherapy. A literature search for studies about CA125-related variables in patients with AOC was undertaken on three databases, by predefined search criteria, and a selection of studies was performed. Sixty-two studies were selected. CA125-related variables were summarized in three groups: response-related, time-to-event, and other CA125-related tumor cell kinetics variables. Even though CA125 changes and half-life after chemotherapy were the most studied, other variables and two models have been well defined, and often showed an interesting power to predict survival. These kinetics variables are related to the CA125 regression curve, pre- and post-chemotherapy kinetics, or are variables inferred from a population model of CA125 kinetics. PMID:26546024

  11. Optimizing advanced propeller designs by simultaneously updating flow variables and design parameters

    NASA Technical Reports Server (NTRS)

    Rizk, Magdi H.

    1988-01-01

    A scheme is developed for solving constrained optimization problems in which the objective function and the constraint function are dependent on the solution of the nonlinear flow equations. The scheme updates the design parameter iterative solutions and the flow variable iterative solutions simultaneously. It is applied to an advanced propeller design problem with the Euler equations used as the flow governing equations. The scheme's accuracy, efficiency and sensitivity to the computational parameters are tested.

  12. Aerodynamic optimization by simultaneously updating flow variables and design parameters with application to advanced propeller designs

    NASA Technical Reports Server (NTRS)

    Rizk, Magdi H.

    1988-01-01

    A scheme is developed for solving constrained optimization problems in which the objective function and the constraint function are dependent on the solution of the nonlinear flow equations. The scheme updates the design parameter iterative solutions and the flow variable iterative solutions simultaneously. It is applied to an advanced propeller design problem with the Euler equations used as the flow governing equations. The scheme's accuracy, efficiency and sensitivity to the computational parameters are tested.

  13. Mercury in freshwater ecosystems of the Canadian Arctic: recent advances on its cycling and fate.

    PubMed

    Chételat, John; Amyot, Marc; Arp, Paul; Blais, Jules M; Depew, David; Emmerton, Craig A; Evans, Marlene; Gamberg, Mary; Gantner, Nikolaus; Girard, Catherine; Graydon, Jennifer; Kirk, Jane; Lean, David; Lehnherr, Igor; Muir, Derek; Nasr, Mina; Poulain, Alexandre J; Power, Michael; Roach, Pat; Stern, Gary; Swanson, Heidi; van der Velden, Shannon

    2015-03-15

    The Canadian Arctic has vast freshwater resources, and fish are important in the diet of many Northerners. Mercury is a contaminant of concern because of its potential toxicity and elevated bioaccumulation in some fish populations. Over the last decade, significant advances have been made in characterizing the cycling and fate of mercury in these freshwater environments. Large amounts of new data on concentrations, speciation and fluxes of Hg are provided and summarized for water and sediment, which were virtually absent for the Canadian Arctic a decade ago. The biogeochemical processes that control the speciation of mercury remain poorly resolved, including the sites and controls of methylmercury production. Food web studies have examined the roles of Hg uptake, trophic transfer, and diet for Hg bioaccumulation in fish, and, in particular, advances have been made in identifying determinants of mercury levels in lake-dwelling and sea-run forms of Arctic char. In a comparison of common freshwater fish species that were sampled across the Canadian Arctic between 2002 and 2009, no geographic patterns or regional hotspots were evident. Over the last two to four decades, Hg concentrations have increased in some monitored populations of fish in the Mackenzie River Basin while other populations from the Yukon and Nunavut showed no change or a slight decline. The different Hg trends indicate that the drivers of temporal change may be regional or habitat-specific. The Canadian Arctic is undergoing profound environmental change, and preliminary evidence suggests that it may be impacting the cycling and bioaccumulation of mercury. Further research is needed to investigate climate change impacts on the Hg cycle as well as biogeochemical controls of methylmercury production and the processes leading to increasing Hg levels in some fish populations in the Canadian Arctic. PMID:24993511

  14. Incorporation of a risk analysis approach for the nuclear fuel cycle advanced transparency framework.

    SciTech Connect

    Mendez, Carmen Margarita; York, David L.; Inoue, Naoko; Kitabata, Takuya; Vugrin, Eric D.; Vugrin, Kay White; Rochau, Gary Eugene; Cleary, Virginia D.

    2007-05-01

    Proliferation resistance features that reduce the likelihood of diversion of nuclear materials from the civilian nuclear power fuel cycle are critical for a global nuclear future. A framework that monitors process information continuously can demonstrate the ability to resist proliferation by measuring and reducing diversion risk, thus ensuring the legitimate use of the nuclear fuel cycle. The automation of new nuclear facilities requiring minimal manual operation makes this possible by generating instantaneous system state data that can be used to track and measure the status of the process and material at any given time. Sandia National Laboratories (SNL) and the Japan Atomic Energy Agency (JAEA) are working in cooperation to develop an advanced transparency framework capable of assessing diversion risk in support of overall plant transparency. The ''diversion risk'' quantifies the probability and consequence of a host nation diverting nuclear materials from a civilian fuel cycle facility. This document introduces the details of the diversion risk quantification approach to be demonstrated in the fuel handling training model of the MONJU Fast Reactor.

  15. Determination of Anaerobic Threshold by Heart Rate or Heart Rate Variability using Discontinuous Cycle Ergometry

    PubMed Central

    PARK, SUNG WOOK; BRENNEMAN, MICHAEL; COOKE, WILLIAM H.; CORDOVA, ALBERTO; FOGT, DONOVAN

    2014-01-01

    The purpose was to determine if heart rate (HR) and heart rate variability (HRV) responses would reflect anaerobic threshold (AT) using a discontinuous, incremental, cycle test. AT was determined by ventilatory threshold (VT). Cyclists (30.6±5.9y; 7 males, 8 females) completed a discontinuous cycle test consisting of 7 stages (6 min each with 3 min of rest between). Three stages were performed at power outputs (W) below those corresponding to a previously established AT, one at W corresponding to AT, and 3 at W above those corresponding to AT. The W at the intersection of the trend lines was considered each metric’s “threshold”. The averaged stage data for Ve, HR, and time- and frequency-domain HRV metrics were plotted versus W. The W at the “threshold” for the metrics of interest were compared using correlation analysis and paired-sample t-test. In all, several heart rate-related parameters accurately reflected AT with significant correlations (p≤0.05) were observed between AT W and HR, mean RR interval (MRR), low and high frequency spectral energy (LF and HR, respectively), high frequency peak (fHF), and HFxfHF metrics’ threshold W (i.e., MRRTW, etc.). Differences in HR or HRV metric threshold W and AT for all subjects were less than 14 W. The steady state data from discontinuous protocols may allow for a true indication of steady-state physiologic stress responses and corresponding W at AT, compared to continuous protocols using 1–2 min exercise stages. PMID:27182400

  16. SOLAR CYCLE VARIABILITY AND SURFACE DIFFERENTIAL ROTATION FROM Ca II K-LINE TIME SERIES DATA

    SciTech Connect

    Scargle, Jeffrey D.; Worden, Simon P.; Keil, Stephen L.

    2013-07-01

    Analysis of over 36 yr of time series data from the NSO/AFRL/Sac Peak K-line monitoring program elucidates 5 components of the variation of the 7 measured chromospheric parameters: (a) the solar cycle (period {approx} 11 yr), (b) quasi-periodic variations (periods {approx} 100 days), (c) a broadband stochastic process (wide range of periods), (d) rotational modulation, and (e) random observational errors, independent of (a)-(d). Correlation and power spectrum analyses elucidate periodic and aperiodic variation of these parameters. Time-frequency analysis illuminates periodic and quasi-periodic signals, details of frequency modulation due to differential rotation, and in particular elucidates the rather complex harmonic structure (a) and (b) at timescales in the range {approx}0.1-10 yr. These results using only full-disk data suggest that similar analyses will be useful for detecting and characterizing differential rotation in stars from stellar light curves such as those being produced by NASA's Kepler observatory. Component (c) consists of variations over a range of timescales, in the manner of a 1/f random process with a power-law slope index that varies in a systematic way. A time-dependent Wilson-Bappu effect appears to be present in the solar cycle variations (a), but not in the more rapid variations of the stochastic process (c). Component (d) characterizes differential rotation of the active regions. Component (e) is of course not characteristic of solar variability, but the fact that the observational errors are quite small greatly facilitates the analysis of the other components. The data analyzed in this paper can be found at the National Solar Observatory Web site http://nsosp.nso.edu/cak{sub m}on/, or by file transfer protocol at ftp://ftp.nso.edu/idl/cak.parameters.

  17. Solar Cycle Variability and Surface Differential Rotation from Ca II K-line Time Series Data

    NASA Astrophysics Data System (ADS)

    Scargle, Jeffrey D.; Keil, Stephen L.; Worden, Simon P.

    2013-07-01

    Analysis of over 36 yr of time series data from the NSO/AFRL/Sac Peak K-line monitoring program elucidates 5 components of the variation of the 7 measured chromospheric parameters: (a) the solar cycle (period ~ 11 yr), (b) quasi-periodic variations (periods ~ 100 days), (c) a broadband stochastic process (wide range of periods), (d) rotational modulation, and (e) random observational errors, independent of (a)-(d). Correlation and power spectrum analyses elucidate periodic and aperiodic variation of these parameters. Time-frequency analysis illuminates periodic and quasi-periodic signals, details of frequency modulation due to differential rotation, and in particular elucidates the rather complex harmonic structure (a) and (b) at timescales in the range ~0.1-10 yr. These results using only full-disk data suggest that similar analyses will be useful for detecting and characterizing differential rotation in stars from stellar light curves such as those being produced by NASA's Kepler observatory. Component (c) consists of variations over a range of timescales, in the manner of a 1/f random process with a power-law slope index that varies in a systematic way. A time-dependent Wilson-Bappu effect appears to be present in the solar cycle variations (a), but not in the more rapid variations of the stochastic process (c). Component (d) characterizes differential rotation of the active regions. Component (e) is of course not characteristic of solar variability, but the fact that the observational errors are quite small greatly facilitates the analysis of the other components. The data analyzed in this paper can be found at the National Solar Observatory Web site http://nsosp.nso.edu/cak_mon/, or by file transfer protocol at ftp://ftp.nso.edu/idl/cak.parameters.

  18. Renovation of Chemical Processing Facility for Development of Advanced Fast Reactor Fuel Cycle System in JNC

    SciTech Connect

    Atsushi Aoshima; Shigehiko Miyachi; Takashi Suganuma; Shinichi Nemoto

    2002-07-01

    The CPF had 4 laboratories (operation room A, laboratory A, laboratory C and analysis laboratory) in connection with reprocessing technology. The main laboratory, operation room A, has 5 hot cells. Since equipment in the main cell had been designed for small-scale verification of existing reprocessing steps, it was hardly able to respond flexibly to experimental studies on advanced technology. It was decided to remodel the cell according to the design that was newly laid out in order to ensure the function and space to conduct various basic tests. The other laboratories had no glove boxes for conducting basic experiments of important elements in the advanced reprocessing, such as actinides except U and Pu, lanthanides and so on. In order to meet various requirements of innovative technologies on advanced fuel cycle development, one laboratory is established more for study on dry reprocessing, and glove boxes, hoods and analytical equipment such as NMR, FT-IR, TI-MS are newly installed in the other laboratories in this renovation. After the renovation, hot tests in the CPF will be resumed from April 2002. (authors)

  19. Moraine formation during an advance/retreat cycle at a temperate alpine glacier

    NASA Astrophysics Data System (ADS)

    Brook, M.; Quincey, D.; Winkler, S.

    2012-04-01

    Mountain glaciers are highly sensitive to variations in temperature and precipitation, and so moraine records from such systems are strong indicators of climate change. Due to the prevailing trend of retreat of the majority of mountain glaciers globally over the last few decades, there are limited opportunities to observe moraine formation, especially at temperate alpine glaciers. In the Southern Alps of New Zealand, while glaciers have all experienced a major retreat since the late 19th century, within this loss of ice mass, there has been a distinct variance in individual glacier response. Indeed, while Tasman Glacier, the longest glacier in the Southern Alps has thinned and entered into the current phase of calving retreat in the early 1990s, the steeper, more responsive glaciers to the west of the Main Divide, such as Franz Josef and Fox Glacier have experienced more elaborate advance/retreat phases. We focus on moraine formation at Fox Glacier, a c. 12.5 km long valley glacier terminating at 300 m above sea level. Fox Glacier retreated substantially since the 1930s, before advancing 800 m between the mid-1980s and 1999. A minor retreat then followed until 2005, succeeded by a 300 m re-advance until 2007-8. Continued retreat and down-wasting has since followed. Superimposed on this alternating advance/retreat cycle, have been minor winter re-advances. Sedimentological and morphological information were combined with detailed observations, historical photos and recent time-lapse photography of the terminus. Characteristics of several modes of moraine formation have been observed: (1) the late 20th century advance culminated in a broad <5 m high terminal moraine, formed by an admixture of "bulldozed" proglacial sediments and dumping of supraglacial material; (2) the 21st century short-lived advances were characterized by 1-2 m high (often multi-crested) ridges with a "saw-tooth" plan-form controlled by longitudinal crevasses outcropping at the terminus; (3) time

  20. Seismic Cycle Variability in Space and Time: The Sumatran Sunda Megathrust as a Behavior Catalog

    NASA Astrophysics Data System (ADS)

    Philibosian, B.; Sieh, K.; Natawidjaja, D. H.; Avouac, J. P.; Chiang, H. W.; WU, C. C.; Shen, C. C.; Perfettini, H.; Daryono, M. R.; Suwargadi, B. W.

    2015-12-01

    Thanks to the great success of the coral microatoll technique for paleoseismology and paleogeodesy, as well as many recent ruptures, the Sumatran Sunda megathrust has emerged from obscurity to become one of the best-studied faults in the world. Though the reliable historical record is short compared to other areas such as Japan or South America, seismic cycle deformation with high spatial resolution has been reconstructed over multiple cycles based on coral records. This unique level of detail has revealed many complexities that would be difficult to discern using other methods. Some of these features may be specific to the Sumatran case, but it is likely that many other subduction megathrusts and other fault systems exhibit similar behaviors. The low elevations of Holocene corals throughout the outer arc islands indicate little or no active permanent upper plate deformation, suggesting that the Sunda megathrust behaves almost purely elastically. At first order, the fault behavior is well-described by the classical model of fault segmentation with quasi-periodic characteristic ruptures along each segment. Two well-defined segment boundaries, barriers to rupture that persist over multiple seismic cycles, have been identified. However, within each segment there are potentially multiple fault asperities that may rupture individually or combine to form larger events. The Nias-Simeulue segment is relatively short and appears dominated by single end-to-end ruptures, while the longer Mentawai segment characteristically exhibits supercycles. In the supercycle case, each long interseismic period culminates in a temporal cluster of partially overlapping ruptures that in summation relieve stress over the entire segment. Each rupture sequence in our record evolved uniquely, likely indicating that fault slip is controlled by variations in fault frictional properties at spatial scales of ~100 km and temporal scales of a decade. The megathrust is also segmented along dip: the

  1. Variability of space climate and its extremes with successive solar cycles

    NASA Astrophysics Data System (ADS)

    Chapman, Sandra; Hush, Phillip; Tindale, Elisabeth; Dunlop, Malcolm; Watkins, Nicholas

    2016-04-01

    Auroral geomagnetic indices coupled with in situ solar wind monitors provide a comprehensive data set, spanning several solar cycles. Space climate can be considered as the distribution of space weather. We can then characterize these observations in terms of changing space climate by quantifying how the statistical properties of ensembles of these observed variables vary between different phases of the solar cycle. We first consider the AE index burst distribution. Bursts are constructed by thresholding the AE time series; the size of a burst is the sum of the excess in the time series for each time interval over which the threshold is exceeded. The distribution of burst sizes is two component with a crossover in behaviour at thresholds ≈ 1000 nT. Above this threshold, we find[1] a range over which the mean burst size is almost constant with threshold for both solar maxima and minima. The burst size distribution of the largest events has a functional form which is exponential. The relative likelihood of these large events varies from one solar maximum and minimum to the next. If the relative overall activity of a solar maximum/minimum can be estimated, these results then constrain the likelihood of extreme events of a given size for that solar maximum/minimum. We next develop and apply a methodology to quantify how the full distribution of geomagnetic indices and upstream solar wind observables are changing between and across different solar cycles. This methodology[2] estimates how different quantiles of the distribution, or equivalently, how the return times of events of a given size, are changing. [1] Hush, P., S. C. Chapman, M. W. Dunlop, and N. W. Watkins (2015), Robust statistical properties of the size of large burst events in AE, Geophys. Res. Lett.,42 doi:10.1002/2015GL066277 [2] Chapman, S. C., D. A. Stainforth, N. W. Watkins, (2013) On estimating long term local climate trends , Phil. Trans. Royal Soc., A,371 20120287 DOI:10.1098/rsta.2012.0287

  2. Uncertainties in Life Cycle Greenhouse Gas Emissions from Advanced Biomass Feedstock Logistics Supply Chains in Kansas

    SciTech Connect

    Cafferty, Kara G.; Searcy, Erin M.; Nguyen, Long; Spatari, Sabrina

    2014-11-01

    To meet Energy Independence and Security Act (EISA) cellulosic biofuel mandates, the United States will require an annual domestic supply of about 242 million Mg of biomass by 2022. To improve the feedstock logistics of lignocellulosic biofuels and access available biomass resources from areas with varying yields, commodity systems have been proposed and designed to deliver on-spec biomass feedstocks at preprocessing “depots”, which densify and stabilize the biomass prior to long-distance transport and delivery to centralized biorefineries. The harvesting, preprocessing, and logistics (HPL) of biomass commodity supply chains thus could introduce spatially variable environmental impacts into the biofuel life cycle due to needing to harvest, move, and preprocess biomass from multiple distances that have variable spatial density. This study examines the uncertainty in greenhouse gas (GHG) emissions of corn stover logisticsHPL within a bio-ethanol supply chain in the state of Kansas, where sustainable biomass supply varies spatially. Two scenarios were evaluated each having a different number of depots of varying capacity and location within Kansas relative to a central commodity-receiving biorefinery to test GHG emissions uncertainty. Monte Carlo simulation was used to estimate the spatial uncertainty in the HPL gate-to-gate sequence. The results show that the transport of densified biomass introduces the highest variability and contribution to the carbon footprint of the logistics HPL supply chain (0.2-13 g CO2e/MJ). Moreover, depending upon the biomass availability and its spatial density and surrounding transportation infrastructure (road and rail), logistics HPL processes can increase the variability in life cycle environmental impacts for lignocellulosic biofuels. Within Kansas, life cycle GHG emissions could range from 24 to 41 g CO2e/MJ depending upon the location, size and number of preprocessing depots constructed. However, this

  3. Contribution of semi-arid ecosystems to interannual variability of the global carbon cycle.

    PubMed

    Poulter, Benjamin; Frank, David; Ciais, Philippe; Myneni, Ranga B; Andela, Niels; Bi, Jian; Broquet, Gregoire; Canadell, Josep G; Chevallier, Frederic; Liu, Yi Y; Running, Steven W; Sitch, Stephen; van der Werf, Guido R

    2014-05-29

    The land and ocean act as a sink for fossil-fuel emissions, thereby slowing the rise of atmospheric carbon dioxide concentrations. Although the uptake of carbon by oceanic and terrestrial processes has kept pace with accelerating carbon dioxide emissions until now, atmospheric carbon dioxide concentrations exhibit a large variability on interannual timescales, considered to be driven primarily by terrestrial ecosystem processes dominated by tropical rainforests. We use a terrestrial biogeochemical model, atmospheric carbon dioxide inversion and global carbon budget accounting methods to investigate the evolution of the terrestrial carbon sink over the past 30 years, with a focus on the underlying mechanisms responsible for the exceptionally large land carbon sink reported in 2011 (ref. 2). Here we show that our three terrestrial carbon sink estimates are in good agreement and support the finding of a 2011 record land carbon sink. Surprisingly, we find that the global carbon sink anomaly was driven by growth of semi-arid vegetation in the Southern Hemisphere, with almost 60 per cent of carbon uptake attributed to Australian ecosystems, where prevalent La Niña conditions caused up to six consecutive seasons of increased precipitation. In addition, since 1981, a six per cent expansion of vegetation cover over Australia was associated with a fourfold increase in the sensitivity of continental net carbon uptake to precipitation. Our findings suggest that the higher turnover rates of carbon pools in semi-arid biomes are an increasingly important driver of global carbon cycle inter-annual variability and that tropical rainforests may become less relevant drivers in the future. More research is needed to identify to what extent the carbon stocks accumulated during wet years are vulnerable to rapid decomposition or loss through fire in subsequent years. PMID:24847888

  4. The JRC-ITU approach to the safety of advanced nuclear fuel cycles

    SciTech Connect

    Fanghaenel, T.; Rondinella, V.V.; Somers, J.; Konings, R.; Erdmann, N.; Uffelen, P. van; Glatz, J.P.

    2013-07-01

    The JRC-ITU safety studies of advanced fuels and cycles adopt two main axes. First the full exploitation of still available and highly relevant knowledge and samples from past fuel preparation and irradiation campaigns (complementing the limited number of ongoing programmes). Secondly, the shift of focus from simple property measurement towards the understanding of basic mechanisms determining property evolution and behaviour of fuel compounds during normal, off-normal and accident conditions. The final objective of the second axis is the determination of predictive tools applicable to systems and conditions different from those from which they were derived. State of the art experimental facilities, extensive networks of partnerships and collaboration with other organizations worldwide, and a developing programme for training and education are essential in this approach. This strategy has been implemented through various programs and projects. The SUPERFACT programme constitutes the main body of existing knowledge on the behavior in-pile of MOX fuel containing minor actinides. It encompassed all steps of a closed fuel cycle. Another international project investigating the safety of a closed cycle is METAPHIX. In this case a U-Pu19-Zr10 metal alloy containing Np, Am and Cm constitutes the fuel. 9 test pins have been prepared and irradiated. In addition to the PIE (Post Irradiation Examination), pyrometallurgical separation of the irradiated fuel has been performed, to demonstrate all the steps of a multiple recycling closed cycle and characterize their safety relevant aspects. Basic studies like thermodynamic fuel properties, fuel-cladding-coolant interactions have also been carried out at JRC-ITU.

  5. Shoulder Pain and Cycle to Cycle Kinematic Spatial Variability during Recovery Phase in Manual Wheelchair Users: A Pilot Investigation

    PubMed Central

    Jayaraman, Chandrasekaran; Moon, Yaejin; Rice, Ian M.; Hsiao Wecksler, Elizabeth T.; Beck, Carolyn L.; Sosnoff, Jacob J.

    2014-01-01

    Wheelchair propulsion plays a significant role in the development of shoulder pain in manual wheelchair users (MWU). However wheelchair propulsion metrics related to shoulder pain are not clearly understood. This investigation examined intra-individual kinematic spatial variability during semi-circular wheelchair propulsion as a function of shoulder pain in MWU. Data from 10 experienced adult MWU with spinal cord injury (5 with shoulder pain; 5 without shoulder pain) were analyzed in this study. Participants propelled their own wheelchairs on a dynamometer at 3 distinct speeds (self-selected, 0.7 m/s, 1.1 m/s) for 3 minutes at each speed. Motion capture data of the upper limbs were recorded. Intra-individual kinematic spatial variability of the steady state wrist motion during the recovery phase was determined using principal component analysis (PCA). The kinematic spatial variability was calculated at every 10% intervals (i.e at 11 interval points, from 0% to 100%) along the wrist recovery path. Results Overall, spatial variability was found to be highest at the start and end of the recovery phase and lowest during the middle of the recovery path. Individuals with shoulder pain displayed significantly higher kinematic spatial variability than individuals without shoulder pain at the start (at 10% interval) of the recovery phase (p<.004). Conclusions Analysis of intra-individual kinematic spatial variability during the recovery phase of manual wheelchair propulsion distinguished between those with and without shoulder pain. Variability analysis of wheelchair propulsion may offer a new approach to monitor the development and rehabilitation of shoulder pain. PMID:24614232

  6. Seasonal cycles and variability of O3 and H2O in the UT/LMS during SPURT

    NASA Astrophysics Data System (ADS)

    Krebsbach, M.; Schiller, C.; Brunner, D.; Günther, G.; Hegglin, M. I.; Mottaghy, D.; Riese, M.; Spelten, N.; Wernli, H.

    2006-01-01

    Airborne high resolution in situ measurements of a large set of trace gases including ozone (O3) and total water (H2O) in the upper troposphere and the lowermost stratosphere (UT/LMS) have been performed above Europe within the SPURT project. SPURT provides an extensive data coverage of the UT/LMS in each season within the time period between November 2001 and July 2003.

    In the LMS a distinct spring maximum and autumn minimum is observed in O3, whereas its annual cycle in the UT is shifted by 2-3 months later towards the end of the year. The more variable H2O measurements reveal a maximum during summer and a minimum during autumn/winter with no phase shift between the two atmospheric compartments.

    For a comprehensive insight into trace gas composition and variability in the UT/LMS several statistical methods are applied using chemical, thermal and dynamical vertical coordinates. In particular, 2-dimensional probability distribution functions serve as a tool to transform localised aircraft data to a more comprehensive view of the probed atmospheric region. It appears that both trace gases, O3 and H2O, reveal the most compact arrangement and are best correlated in the view of potential vorticity (PV) and distance to the local tropopause, indicating an advanced mixing state on these surfaces. Thus, strong gradients of PV seem to act as a transport barrier both in the vertical and the horizontal direction. The alignment of trace gas isopleths reflects the existence of a year-round extra-tropical tropopause transition layer. The SPURT measurements reveal that this layer is mainly affected by stratospheric air during winter/spring and by tropospheric air during autumn/summer.

    Normalised mixing entropy values for O3 and H2O in the LMS appear to be maximal during spring and summer, respectively, indicating highest variability of these trace gases during the respective seasons.

  7. The spatial and temporal variability of the seasonal mean sea level cycle in the South China Sea

    NASA Astrophysics Data System (ADS)

    Muhaimin Amiruddin, Abd; Haigh, Ivan; Tsimplis, Mikis; Calafat, Francisco; Dangendorf, Soenke

    2015-04-01

    The seasonal cycle is the most energetic component of mean sea level variability and changes in either its amplitude or phase can seriously impact the risk of coastal flooding. Here, tide gauge records and satellite altimetry observations, along with steric and meteorological data are used to investigate the spatial and temporal variability of the seasonal cycle in the South China Sea (SCS) and its forcing mechanisms. The coastal annual amplitude varies significantly from region to region with values ranging from 2 cm to 24 cm, and generally peaks between July and January. The coastal semi-annual amplitude has maximum values of 7 cm, and it peaks between March and June. Along the coast, the seasonal cycle accounts on average for 60% with maximum values of up to 92% of the mean monthly sea level variability. Atmospheric pressure fluctuations explain a significant portion of the seasonal cycle with dominant annual signals in the northern SCS, the Gulf of Thailand and the north-western Philippines Sea. The wind forcing is dominant on the shelf areas of the SCS and the Gulf of Thailand where a simple barotropic model forced by local wind shows amplitudes of up to 27 cm. In the deep basin of the SCS, the Philippines Sea and the shallow Malacca Strait, the steric component is the major contributor with maximum annual amplitudes of up to 15 cm. Significant variability in the annual and semi-annual cycle is found on a year-to-year basis. The annual and semi-annual amplitudes vary by up to 63% and 45% of the maximum values, 15 cm and 11 cm, respectively. On average, stepwise regression analysis of contribution of different forcing factors accounts for 69% of the temporal variability of the annual cycle. The zonal wind and the cross-shore wind were found to exert considerable influence in the Malacca Strait and the northern SCS respectively.

  8. Segmentation of EUV spectroheliograms to track and measure solar EUVI variability within a solar cycle

    NASA Astrophysics Data System (ADS)

    Martinez-Galarce, D. S.; Slater, G. L.; Mcintosh, S. W.

    2011-12-01

    of ~1.3 solar cycles (~16 years). Using this segmented imaging approach the goal of the study is to determine solar EUVI variability observed in each EIT bandpass, as a function of areal identification (e.g., active vs. coronal hole EUV variability), over the entire period of observations.

  9. Ice surface temperatures: seasonal cycle and daily variability from in-situ and satellite observations

    NASA Astrophysics Data System (ADS)

    Madsen, Kristine S.; Dybkjær, Gorm; Høyer, Jacob L.; Nielsen-Englyst, Pia; Rasmussen, Till A. S.; Tonboe, Rasmus T.

    2016-04-01

    Surface temperature is an important parameter for understanding the climate system, including the Polar Regions. Yet, in-situ temperature measurements over ice- and snow covered regions are sparse and unevenly distributed, and atmospheric circulation models estimating surface temperature may have large biases. To change this picture, we will analyse the seasonal cycle and daily variability of in-situ and satellite observations, and give an example of how to utilize the data in a sea ice model. We have compiled a data set of in-situ surface and 2 m air temperature observations over land ice, snow, sea ice, and from the marginal ice zone. 2523 time series of varying length from 14 data providers, with a total of more than 13 million observations, have been quality controlled and gathered in a uniform format. An overview of this data set will be presented. In addition, IST satellite observations have been processed from the Metop/AVHRR sensor and a merged analysis product has been constructed based upon the Metop/AVHRR, IASI and Modis IST observations. The satellite and in-situ observations of IST are analysed in parallel, to characterize the IST variability on diurnal and seasonal scales and its spatial patterns. The in-situ data are used to estimate sampling effects within the satellite observations and the good coverage of the satellite observations are used to complete the geographical variability. As an example of the application of satellite IST data, results will be shown from a coupled HYCOM-CICE ocean and sea ice model run, where the IST products have been ingested. The impact of using IST in models will be assessed. This work is a part of the EUSTACE project under Horizon 2020, where the ice surface temperatures form an important piece of the puzzle of creating an observationally based record of surface temperatures for all corners of the Earth, and of the ESA GlobTemperature project which aims at applying surface temperatures in models in order to

  10. Variability of mesospheric water vapor above Bern in relation to the 27-day solar rotation cycle

    NASA Astrophysics Data System (ADS)

    Lainer, Martin; Hocke, Klemens; Kämpfer, Niklaus

    2016-06-01

    Many studies investigated solar-terrestrial responses (thermal state, O3, OH, H2O) with emphasis on the tropical upper atmosphere. In this paper the focus is switched to water vapor in the mesosphere at a mid-latitudinal location. Eight years of water vapor profile measurements above Bern (46.88 ° N / 7.46 ° E) are investigated to study oscillations with the focus on periods between 10 and 50 days. Different spectral analyses revealed prominent features in the 27-day oscillation band, which are enhanced in the upper mesosphere (above 0.1 hPa, ∼ 64 km) during the rising sunspot activity of solar cycle 24. Local as well as zonal mean Aura MLS observations support these results by showing a similar behavior. The relationship between mesospheric water and the solar Lyman-α flux is studied by comparing the similarity of their temporal oscillations. The H2O oscillation is negatively correlated to solar Lyman-α oscillation with a correlation coefficient of up to - 0.3 to - 0.4, and the phase lag is 6-10 days at 0.04 hPa. The confidence level of the correlation is ≥ 99 %. This finding supports the assumption that the 27-day oscillation in Lyman-α causes a periodical photodissociation loss in mesospheric water. Wavelet power spectra, cross-wavelet transform and wavelet coherence analysis (WTC) complete our study. More periods of high common wavelet power of H2O and solar Lyman-α are present when amplitudes of the Lyman-α flux increase. Since this is not a measure of physical correlation a more detailed view on WTC is necessary, where significant (two sigma level) correlations occur intermittently in the 27 and 13-day band with variable phase lock behavior. Large Lyman-α oscillations appeared after the solar superstorm in July 2012 and the H2O oscillations show a well pronounced anti-correlation. The competition between advective transport and photodissociation loss of mesospheric water vapor may explain the sometimes variable phase relationship of mesospheric H2

  11. Highly Variable Cycle Nozzle Concept: Validation of Flow and Noise Predictions

    NASA Technical Reports Server (NTRS)

    Halbig, Michael C.

    2011-01-01

    Results from experimental and numerical studies of highly Variable Cycle (HVC) exhaust model were presented. The model was designed and fabricated under a Supersonics NRA awarded to Rolls-Royce. The model had a lobed mixer for the core stream nozzle, and elliptic fan stream nozzle, and an ejector. Experiments included far-field acoustic array, phased array, and Particle Image Velocimetry (PIV) measurements. Numerical studies included flow simulations using the WIND-US code and far-field acoustic solutions using an acoustic analogy developed by Goldstein (2003) and Leib and Goldstein (2011). Far-field acoustic measurements showed increased noise levels over the round baseline nozzle when using non-static forward flight conditions. Phased array measurements showed noise sources near the ejector doors when tones were produced for small ejector door positions. Ejector door separation identified in the experiments was reproduced in the numerical flow simulations. Acoustic solutions were unable to match levels measured in the peak jet noise direction indicating additional development work is needed to predict noise from highly three-dimensional flows.

  12. Air core notch-coil magnet with variable geometry for fast-field-cycling NMR.

    PubMed

    Kruber, S; Farrher, G D; Anoardo, E

    2015-10-01

    In this manuscript we present details on the optimization, construction and performance of a wide-bore (71 mm) α-helical-cut notch-coil magnet with variable geometry for fast-field-cycling NMR. In addition to the usual requirements for this kind of magnets (high field-to-power ratio, good magnetic field homogeneity, low inductance and resistance values) a tunable homogeneity and a more uniform heat dissipation along the magnet body are considered. The presented magnet consists of only one machined metallic cylinder combined with two external movable pieces. The optimal configuration is calculated through an evaluation of the magnetic flux density within the entire volume of interest. The magnet has a field-to-current constant of 0.728 mT/A, allowing to switch from zero to 0.125 T in less than 3 ms without energy storage assistance. For a cylindrical sample volume of 35 cm(3) the effective magnet homogeneity is lower than 130 ppm. PMID:26367321

  13. Impacts of climate variability and extreme events on the terrestrial carbon cycle of the Amazon basin

    NASA Astrophysics Data System (ADS)

    Harper, A. B.; Cox, P.; Wiltshire, A.; Friedlingstein, P.; Jones, C. D.; Mercado, L.; Groenendijk, M.; Sitch, S.

    2013-12-01

    Several climate models predict reduced dry season rainfall in the Amazon region as a consequence of climate change. Drier dry seasons could have profound negative consequences for the forest, since soil moisture levels are already near their lower limit during this time of the year. Two recent dry season droughts (during 2005 and 2010) could provide insight into the future of the region. These droughts were associated with sea surface temperature anomalies in the tropical North Atlantic Ocean. Additionally, El Niño-related temperature anomalies in the tropical Pacific Ocean can lead to drought in the northern Amazon. In this work, we use a land surface model with updated physiology and vegetation dynamics to investigate responses of the Amazon terrestrial carbon cycle to recent droughts. JULES (the Joint UK Land-Environment Simulator) is the land surface model in the Hadley Centre Earth System Model. Several recent model developments have improved its ability to replicate seasonal cycles of land fluxes in tropical forests, such as new plant functional types, plant trait-based physiological parameters, and a multi-layer canopy with two-stream radiation and sunfleck penetration. In addition, several non-standard updates to JULES can improve the model in this region: including a representation of deeper soils and efficient roots, and parameter optimization. The soil and rooting adjustments are based on previous work with the Simple Biosphere (SiB3) model, which has been tested extensively in the Amazon. SiB3 can include a climate-derived, spatially varying predictor of forest drought resistance, which enabled it to simulate forest response to persistent soil moisture deficits during two rainfall exclusion projects in the Amazon. We ran JULES from pre-industrial to present day, forced with observed climate, atmospheric CO2, and land use. A mixture of satellite- and ground-based observations was used to validate JULES seasonal cycles of surface fluxes, phenology

  14. Systems Analysis of an Advanced Nuclear Fuel Cycle Based on a Modified UREX+3c Process

    SciTech Connect

    E. R. Johnson; R. E. Best

    2009-12-28

    The research described in this report was performed under a grant from the U.S. Department of Energy (DOE) to describe and compare the merits of two advanced alternative nuclear fuel cycles -- named by this study as the “UREX+3c fuel cycle” and the “Alternative Fuel Cycle” (AFC). Both fuel cycles were assumed to support 100 1,000 MWe light water reactor (LWR) nuclear power plants operating over the period 2020 through 2100, and the fast reactors (FRs) necessary to burn the plutonium and minor actinides generated by the LWRs. Reprocessing in both fuel cycles is assumed to be based on the UREX+3c process reported in earlier work by the DOE. Conceptually, the UREX+3c process provides nearly complete separation of the various components of spent nuclear fuel in order to enable recycle of reusable nuclear materials, and the storage, conversion, transmutation and/or disposal of other recovered components. Output of the process contains substantially all of the plutonium, which is recovered as a 5:1 uranium/plutonium mixture, in order to discourage plutonium diversion. Mixed oxide (MOX) fuel for recycle in LWRs is made using this 5:1 U/Pu mixture plus appropriate makeup uranium. A second process output contains all of the recovered uranium except the uranium in the 5:1 U/Pu mixture. The several other process outputs are various waste streams, including a stream of minor actinides that are stored until they are consumed in future FRs. For this study, the UREX+3c fuel cycle is assumed to recycle only the 5:1 U/Pu mixture to be used in LWR MOX fuel and to use depleted uranium (tails) for the makeup uranium. This fuel cycle is assumed not to use the recovered uranium output stream but to discard it instead. On the other hand, the AFC is assumed to recycle both the 5:1 U/Pu mixture and all of the recovered uranium. In this case, the recovered uranium is reenriched with the level of enrichment being determined by the amount of recovered plutonium and the combined amount

  15. Holocene climate dynamics, biogeochemical cycles and ecosystem variability in the eastern Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Schmiedl, Gerhard; Adloff, Fanny; Emeis, Kay; Grimm, Rosina; Maier-Reimer, Ernst; Mikolajewicz, Uwe; Möbius, Jürgen; Müller-Navarra, Katharina

    2013-04-01

    The past variability of biogeochemical processes and marine ecosystems of the eastern Mediterranean Sea (EMS) is documented in the form of organic-rich sapropels that occurred at northern hemisphere insolation maxima. In order to understand the processes leading from deglacial and Holocene climate variability to the formation of sapropel S1 via changed biogeochemical cycling in the EMS, we integrated results from global and regional Earth system model experiments with biogeochemical and micropaleontological proxy records. Our results suggest a high spatiotemporal variability of deep-water oxygenation and biogeochemical processes at the sea floor during the late glacial and early Holocene. Changes in trophic conditions of bathyal ecosystems along ocean margins are closely linked to the hydrology of the EMS borderlands; they reflect orbital and sub-orbital climate variations of the high northern latitudes and the African monsoon system. Local trophic conditions were particularly variable in the northern Aegean Sea as a response to changes in riverine runoff and Black Sea outflow. During the time of S1 deposition, average oxygen levels decreased exponentially with increasing water depth, suggesting a basin-wide shallowing of vertical convection superimposed by local signals. In the northernmost Aegean Sea, deep-water ventilation persisted during the early period of S1 formation, owing to temperature-driven local convection and the absence of low-salinity Black Sea outflow. At the same time, severe temporary dysoxia or even short anoxia occurred in the eastern Levantine basin at water depths as shallow as 900 m. This area was likely influenced by enhanced nutrient input of the Nile river that resulted in high organic matter fluxes and related high oxygen-consumption rates in the water column. In contrast, abyssal ecosystems of the Levantine and Ionian basins lack eutrophication during the early Holocene suggesting that enhanced productivity did not play a crucial role

  16. High-speed limnology: using advanced sensors to investigate spatial variability in biogeochemistry and hydrology.

    PubMed

    Crawford, John T; Loken, Luke C; Casson, Nora J; Smith, Colin; Stone, Amanda G; Winslow, Luke A

    2015-01-01

    Advanced sensor technology is widely used in aquatic monitoring and research. Most applications focus on temporal variability, whereas spatial variability has been challenging to document. We assess the capability of water chemistry sensors embedded in a high-speed water intake system to document spatial variability. This new sensor platform continuously samples surface water at a range of speeds (0 to >45 km h(-1)) resulting in high-density, mesoscale spatial data. These novel observations reveal previously unknown variability in physical, chemical, and biological factors in streams, rivers, and lakes. By combining multiple sensors into one platform, we were able to detect terrestrial-aquatic hydrologic connections in a small dystrophic lake, to infer the role of main-channel vs backwater nutrient processing in a large river and to detect sharp chemical changes across aquatic ecosystem boundaries in a stream/lake complex. Spatial sensor data were verified in our examples by comparing with standard lab-based measurements of selected variables. Spatial fDOM data showed strong correlation with wet chemistry measurements of DOC, and optical NO3 concentrations were highly correlated with lab-based measurements. High-frequency spatial data similar to our examples could be used to further understand aquatic biogeochemical fluxes, ecological patterns, and ecosystem processes, and will both inform and benefit from fixed-site data. PMID:25406073

  17. Recent advances in SRS on hydrogen isotope separation using thermal cycling absorption process

    SciTech Connect

    Xiao, X.; Kit Heung, L.; Sessions, H.T.

    2015-03-15

    TCAP (Thermal Cycling Absorption Process) is a gas chromatograph in principle using palladium in the column packing, but it is unique in the fact that the carrier gas, hydrogen, is being isotopically separated and the system is operated in a semi-continuous manner. TCAP units are used to purify tritium. The recent TCAP advances at Savannah River Site (SRS) include compressor-free concept for heating/cooling, push and pull separation using an active inverse column, and compact column design. The new developments allow significantly higher throughput and better reliability from 1/10 of the current production system's footprint while consuming 60% less energy. Various versions are derived in the meantime for external customers to be used in fusion energy projects.

  18. Enterprise SRS: leveraging ongoing operations to advance nuclear fuel cycles research and development programs

    SciTech Connect

    Murray, A.M.; Marra, J.E.; Wilmarth, W.R.; McGuire, P.W.; Wheeler, V.B.

    2013-07-01

    The Savannah River Site (SRS) is re-purposing its vast array of assets (including H Canyon - a nuclear chemical separation plant) to solve issues regarding advanced nuclear fuel cycle technologies, nuclear materials processing, packaging, storage and disposition. The vehicle for this transformation is Enterprise SRS which presents a new, radical view of SRS as a united endeavor for 'all things nuclear' as opposed to a group of distinct and separate entities with individual missions and organizations. Key among the Enterprise SRS strategic initiatives is the integration of research into SRS facilities but also in other facilities in conjunction with on-going missions to provide researchers from other national laboratories, academic institutions, and commercial entities the opportunity to demonstrate their technologies in a relevant environment and scale prior to deployment. To manage that integration of research demonstrations into site facilities, a center for applied nuclear materials processing and engineering research has been established in SRS.

  19. How does complex terrain influence responses of carbon and water cycle processes to climate variability and climate change?

    EPA Science Inventory

    We are pursuing the ambitious goal of understanding how complex terrain influences the responses of carbon and water cycle processes to climate variability and climate change. Our studies take place in H.J. Andrews Experimental Forest, an LTER (Long Term Ecological Research) site...

  20. Comparison of maximum usable frequency (MUF) variability over Peninsular Malaysia with IRI model during the rise of solar cycle 24

    NASA Astrophysics Data System (ADS)

    Malik, R. A.; Abdullah, M.; Abdullah, S.; Homam, M. J.

    2016-02-01

    The aim of this paper is to study maximum usable frequency (MUF) variability over Peninsular Malaysia (112.5°E, 2.5°N) which is located in the equatorial region during the rise of Solar Cycle 24 (2009-2011). The MUF Test data was obtained from high frequency (HF) transmission tests that were conducted from April 2009 to September 2011. Relative variability VR was used to compute the relative variability of MUF. Variability of diurnal, seasonal and sunspot effect on MUF of test was compared to International Reference Ionosphere (IRI) version of 2012. The results show that: (a) MUF from the IRI model is higher than the MUF Test but the magnitude for the MUF Test and IRI are similar; (b) from the diurnal analysis, MUF is more vulnerable to variability during the nighttime than the daytime where the variability range for MUF Test and IRI during daytime is 4-12% compared to the nighttime range of 10-30%; (c) seasonal variability for MUF Test in 2011 indicates no clear trend for all seasons, and the seasonal and monthly variability for both MUF VR in 2011 is lower compared to 2009 and 2010; and (d) when sunspot number increases, MUF VR decreases. This result complements the variability in the equatorial and low latitude regions in that when solar activity increases, variability decreases.

  1. Analysis of R&D Strategy for Advanced Combined Cycle Power Systems

    NASA Astrophysics Data System (ADS)

    Akimoto, Keigo; Hayashi, Ayami; Kosugi, Takanobu; Tomoda, Toshimasa

    This article analyzes and evaluates the R&D strategy for advanced power generation technologies, such as natural gas combined cycles, IGCCs (Integrated coal Gasification Combined Cycles), and large-scale fuel cell power generation systems with a mixed-integer programming model. The R&D processes are explicitly formulated in the model through GERT (Graphical Evaluation and Review Technique), and the data on each required time of R&D was collected through questionnaire surveys among the experts. The obtained cost-effective strategy incorporates the optimum investment allocation among the developments of various elemental technologies, and at the same time, it incorporates the least-cost expansion planning of power systems in Japan including other power generation technologies such as conventional coal, oil, and gas fired, and hydro and wind power. The simulation results show the selection of the cost-effective technology developments and the importance of the concentrated investments in them. For example, IGCC, which has a relatively high thermal efficiency, and LNG-CCs of the assumed two efficiencies are the cost-effective investment targets in the no-CO2-regulation case.

  2. Solar-Cycle Variability of Magnetosheath Fluctuations at Earth and Venus

    NASA Astrophysics Data System (ADS)

    Dwivedi, N. K.; Narita, Y.; Kovacs, P.

    2014-12-01

    The magnetosheath is a region between the bow-shock and magnetopause and the magnetosheath plasma is mostly in the turbulent state. In the present investigation we put an effort to closely examine the magnetosheath fluctuations dependency on the solar-cycles (solar-maximum and solar minimum) at the magnetized planetary body (Earth) and their comparison with the un-magnetized planetary body (Venus) for the solar minimum. We use the CLUSTER FGM data for the solar-maximum (2001-2002), solar-minimum (2006-2008) and Venus fluxgate magnetometer data for the solar-minimum (2006-2008) to perform a comparative statistical study on the energy spectra and probability density function (PDF) and asses the spectral features of the magnetic fluctuations of the both planetary bodies. In the comparison we study the relation between the inertial ranges of the spectra and the temporal scales of non-Gaussian magnetic fluctuations derived from PDF analyses. The first can refer to turbulent cascade dynamics, while the latter may indicate intermittency. We first transformed the magnetic field data into mean field aligned coordinate system with respect to the large-scale magnetic field direction and then after we compute the power spectral density with the help of Welch algorithm. The computed energy spectra of Earth's magnetosheath show a moderate variability with the solar-cycles and have a broader inertial range. However the estimated energy spectra for the solar-minimum at Venus give the clear evidence of the existence of the break point in the vicinity of the ion gyroradius. After the break-point the energy spectra become steeper and show a distinctive spectral scales which is interpreted as the realization of the begging of the energy cascade. We also briefly address the influence of turbulence on the plasma transport and wave dynamics responsible for the spectral break and predict spectral features of the energy spectra for the solar-maximum at Venus based on the results obtained

  3. Analysis of advanced european nuclear fuel cycle scenarios including transmutation and economical estimates

    SciTech Connect

    Merino Rodriguez, I.; Alvarez-Velarde, F.; Martin-Fuertes, F.

    2013-07-01

    In this work the transition from the existing Light Water Reactors (LWR) to the advanced reactors is analyzed, including Generation III+ reactors in a European framework. Four European fuel cycle scenarios involving transmutation options have been addressed. The first scenario (i.e., reference) is the current fleet using LWR technology and open fuel cycle. The second scenario assumes a full replacement of the initial fleet with Fast Reactors (FR) burning U-Pu MOX fuel. The third scenario is a modification of the second one introducing Minor Actinide (MA) transmutation in a fraction of the FR fleet. Finally, in the fourth scenario, the LWR fleet is replaced using FR with MOX fuel as well as Accelerator Driven Systems (ADS) for MA transmutation. All scenarios consider an intermediate period of GEN-III+ LWR deployment and they extend for a period of 200 years looking for equilibrium mass flows. The simulations were made using the TR-EVOL code, a tool for fuel cycle studies developed by CIEMAT. The results reveal that all scenarios are feasible according to nuclear resources demand (U and Pu). Concerning to no transmutation cases, the second scenario reduces considerably the Pu inventory in repositories compared to the reference scenario, although the MA inventory increases. The transmutation scenarios show that elimination of the LWR MA legacy requires on one hand a maximum of 33% fraction (i.e., a peak value of 26 FR units) of the FR fleet dedicated to transmutation (MA in MOX fuel, homogeneous transmutation). On the other hand a maximum number of ADS plants accounting for 5% of electricity generation are predicted in the fourth scenario (i.e., 35 ADS units). Regarding the economic analysis, the estimations show an increase of LCOE (Levelized cost of electricity) - averaged over the whole period - with respect to the reference scenario of 21% and 29% for FR and FR with transmutation scenarios respectively, and 34% for the fourth scenario. (authors)

  4. Trends and variability of the South American hydrological cycle for the last 2000 years

    NASA Astrophysics Data System (ADS)

    Evangelista, Heitor; Gonzalez Arango, Catalina; Nogueira, Juliana; Monteiro, Leonardo; von Gunten, Lucien; Khodri, Myriam; Neukom, Raphael

    2016-04-01

    The South American continent encloses two of the largest global river basins: The Amazon basin and the La Plata basin. Its hydrological cycle is highly dependent on the water vapour transport advected from tropical-equatorial Atlantic as well as the polar advections. The Pacific Ocean contribution in the continental water budget is largely restricted to the western Andes region. Nevertheless, moderate-to-intense ENSO periods strongly affect more than half of the South American hydrology, influencing the availability of water resources from mountainous regions that are vital to ecosystems and the human economy and wellbeing. Intense droughts and floods observed continentally during the modern epoch have pointed to the need of better understanding the regional climate related issue. Recent paleoclimate advances, especially the creation of high-standard regional proxy record databases, allow describing the South American climate from a new perspective. However, large areas of tropical South America are still underrepresented in those databases. Here we present an effort of the South American PAGES 2k paleo-community LOTRED-SA to fill this gap. The group aims at producing a South American hydro-climate reconstruction from 267 proxy records (mostly tree rings, ice cores, pollen, instrumental precipitation and river flow) and 14 high resolved speleothems data covering the common era. For this study we plan to reanalyse new and existing tree ring and pollen data with respect to instrumental climate data. The well calibrated tree-ring index will be compared to an independently developed hydro-climate reconstruction for the last 2K based on speleothem records (Khodri et al., in prep) using coherence and singular spectral analyses to depict the temporal evolution of the dominant cyclicities the time series. For the more recent period, we will also use long-term instrumental data of precipitation, river flow and air temperature.

  5. Identification of Diurnal, Seasonal and Inter-Annual Variability Across SE Asian Field Observations of key Water Cycle Variables: Rainfall, net Radiation, Total Evaporation and River Discharge

    NASA Astrophysics Data System (ADS)

    Solera García, M. A.; Tych, W.; Chappell, N.

    2007-12-01

    The identification of periodic patterns in water cycle variables is critical to the understanding of land-atmosphere interactions, climate change and the evaluation of General Circulation Model (GCM) output. SE Asia in particular plays a very important role on the global climate because it is a large source of energy and water fluxes into the upper atmosphere. Cycle identification is carried out following the Data Based Mechanistic (DBM) philosophy, which focuses on the use of parsimonious, rigorous models which are characterised by lack of a priori assumptions, built in uncertainty analysis and final model acceptance dependent on the physical interpretation of the results. The DBM tool used here is the Unobserved Component - Dynamic Harmonic Regression (UC-DHR) model, which is a statistical method that allows the identification of variability in time series by introducing Time Variable Parameter (TVP) estimation of harmonic components. UC-DHR is not scale dependent and was thus applied to both hourly (to investigate diurnal variation) and fortnightly datasets (for intra- and inter-annual variability). The data used in the analysis has been gathered from existing catchment datasets for three regions of tropical SE Asia, namely Northern Thailand, Central Peninsular Malaysia and Northeast Borneo. These regions were chosen because they represent the hydro-climatic gradient (seasonal to equatorial) present within the tropics and because SE Asia has the most extensive set of catchment/plot studies within the humid tropics. Results show modeling tools were able to quantify the main patterns present in the observations throughout different time scales (diurnal, intra-annual and inter-annual) and the strength of the correlation pattern between the four hydro-climatic variables. The subsequent discussion focuses on the physical processes behind those patterns (e.g. diurnal variability caused by local convection due to solar heating; impact of El Niño Southern Oscillation

  6. Rocket-Based Combined Cycle Activities in the Advanced Space Transportation Program Office

    NASA Technical Reports Server (NTRS)

    Hueter, Uwe; Turner, James

    1999-01-01

    NASA's Office of Aero-Space Technology (OAST) has established three major goals, referred to as, "The Three Pillars for Success". The Advanced Space Transportation Program Office (ASTP) at the NASA's Marshall Space Flight Center (MSFC) in Huntsville, Ala. focuses on future space transportation technologies Under the "Access to Space" pillar. The Core Technologies Project, part of ASTP, focuses on the reusable technologies beyond those being pursued by X-33. One of the main activities over the past two and a half years has been on advancing the rocket-based combined cycle (RBCC) technologies. In June of last year, activities for reusable launch vehicle (RLV) airframe and propulsion technologies were initiated. These activities focus primarily on those technologies that support the decision to determine the path this country will take for Space Shuttle and RLV. This year, additional technology efforts in the reusable technologies will be awarded. The RBCC effort that was completed early this year was the initial step leading to flight demonstrations of the technology for space launch vehicle propulsion.

  7. Propulsion/ASME Rocket-Based Combined Cycle Activities in the Advanced Space Transportation Program Office

    NASA Technical Reports Server (NTRS)

    Hueter, Uwe; Turner, James

    1998-01-01

    NASA's Office Of Aeronautics and Space Transportation Technology (OASTT) has establish three major coals. "The Three Pillars for Success". The Advanced Space Transportation Program Office (ASTP) at the NASA's Marshall Space Flight Center in Huntsville,Ala. focuses on future space transportation technologies under the "Access to Space" pillar. The Advanced Reusable Technologies (ART) Project, part of ASTP, focuses on the reusable technologies beyond those being pursued by X-33. The main activity over the past two and a half years has been on advancing the rocket-based combined cycle (RBCC) technologies. In June of last year, activities for reusable launch vehicle (RLV) airframe and propulsion technologies were initiated. These activities focus primarily on those technologies that support the year 2000 decision to determine the path this country will take for Space Shuttle and RLV. In February of this year, additional technology efforts in the reusable technologies were awarded. The RBCC effort that was completed early this year was the initial step leading to flight demonstrations of the technology for space launch vehicle propulsion. Aerojet, Boeing-Rocketdyne and Pratt & Whitney were selected for a two-year period to design, build and ground test their RBCC engine concepts. In addition, ASTROX, Pennsylvania State University (PSU) and University of Alabama in Huntsville also conducted supporting activities. The activity included ground testing of components (e.g., injectors, thrusters, ejectors and inlets) and integrated flowpaths. An area that has caused a large amount of difficulty in the testing efforts is the means of initiating the rocket combustion process. All three of the prime contractors above were using silane (SiH4) for ignition of the thrusters. This follows from the successful use of silane in the NASP program for scramjet ignition. However, difficulties were immediately encountered when silane (an 80/20 mixture of hydrogen/silane) was used for rocket

  8. Linking Rainfall Variability and Carbon Cycling in a Green Roof Ecosystem

    NASA Astrophysics Data System (ADS)

    Potts, D. L.; Warren, R. J., II; Ivancic, T. A.

    2015-12-01

    Whereas green roof hydrology is well-studied, these systems present a novel opportunity to examine plant-mediated linkages between rainfall and carbon cycling. For example, green roofs experience dramatic fluctuations in soil moisture because they have limited soil water holding capacity and high rates of evaporation. Stonecrop (Sedum spp.) is widely planted in green roofs and its traits reflect an overall strategy of water conservation. In addition to succulent leaves and a slow growth rate, several stonecrop species possess inducible CAM photosynthesis. We made continuous measurements of ecosystem CO2 exchange, soil temperature (T), and volumetric soil moisture (θ) using a chamber-based automated monitoring system installed on a 3-year old green roof located in Buffalo, New York. Concurrent measurements of net ecosystem CO2 exchange (NEE) and ecosystem respiration (Re) allowed us to estimate gross ecosystem CO2 exchange (GEE). We predicted that CAM photosynthesis by stonecrop would be induced by high T and low θ and would manifest at the ecosystem scale by a reductions in both reduced midday CO2 uptake associated with stomatal closure and nighttime net CO2 efflux as CAM-driven assimilation offset respiratory losses. Not surprisingly, increased T and decreased θ negatively influenced GEE while Re increased in response to increased T and θ. During a period of unusually hot, dry conditions the responses of GEE and Re were reflected in a decline in daytime NEE. However, this decline in NEE was not associated with a similar reduction in nighttime Re suggesting that these conditions were insufficient to induce CAM photosynthesis. Future ecohydrological investigations of green roofs may provide new insights into how rainfall variability interacts with plant traits, community diversity, and edaphic factors to shape ecosystem function.

  9. Environmental life cycle assessment of grain maize production: An analysis of factors causing variability.

    PubMed

    Boone, Lieselot; Van Linden, Veerle; De Meester, Steven; Vandecasteele, Bart; Muylle, Hilde; Roldán-Ruiz, Isabel; Nemecek, Thomas; Dewulf, Jo

    2016-05-15

    To meet the growing demand, high yielding, but environmentally sustainable agricultural plant production systems are desired. Today, life cycle assessment (LCA) is increasingly used to assess the environmental impact of these agricultural systems. However, the impact results are very diverse due to management decisions or local natural conditions. The impact of grain maize is often generalized and an average is taken. Therefore, we studied variation in production systems. Four types of drivers for variability are distinguished: policy, farm management, year-to-year weather variation and innovation. For each driver, scenarios are elaborated using ReCiPe and CEENE (Cumulative Exergy Extraction from the Natural Environment) to assess the environmental footprint. Policy limits fertilisation levels in a soil-specific way. The resource consumption is lower for non-sandy soils than for sandy soils, but entails however more eutrophication. Farm management seems to have less influence on the environmental impact when considering the CEENE only. But farm management choices such as fertiliser type have a large effect on emission-related problems (e.g. eutrophication and acidification). In contrast, year-to-year weather variation results in large differences in the environmental footprint. The difference in impact results between favourable and poor environmental conditions amounts to 19% and 17% in terms of resources and emissions respectively, and irrigation clearly is an unfavourable environmental process. The best environmental performance is obtained by innovation as plant breeding results in a steadily increasing yield over 25 years. Finally, a comparison is made between grain maize production in Flanders and a generically applied dataset, based on Swiss practices. These very different results endorse the importance of using local data to conduct LCA of plant production systems. The results of this study show decision makers and farmers how they can improve the

  10. A {approx} 40 YEAR VARIABILITY CYCLE IN THE LUMINOUS BLUE VARIABLE/WOLF-RAYET BINARY SYSTEM HD 5980?

    SciTech Connect

    Koenigsberger, Gloria; Hillier, D. John; Morrell, Nidia; Gamen, Roberto E-mail: georgiev@astro.unam.m E-mail: nmorrell@lco.c E-mail: rgamen@gmail.co

    2010-06-15

    The massive Wolf-Rayet stellar system HD 5980 in the Small Magellanic Cloud entered a sudden and brief {approx} 1-3 mag eruptive state in the mid-1990s. The cause of the instability is not yet understood, but mechanisms similar to those in luminous blue variables are suspected. Using a previously unreported set of spectroscopic data obtained in 1955-1967 and recently acquired optical and HST/STIS spectra, we find that (1) the brief eruptions of 1993 and 1994 occurred at the beginning of an extended ({approx} decades) high state of activity characterized by large emission-line intensities; (2) the level of activity is currently subsiding; and (3) another strong emission-line episode appears to have occurred between 1960 and 1965, suggesting the possibility that the long-term cyclical variability may be recurrent on a {approx} 40 year timescale. These characteristics suggest the possible classification of HD 5980 as an S Doradus-type variable. The effects due to binary interactions in the system are discussed, and we tentatively suggest that the short duration and relatively hot spectral type (WN11/B1.5I) observed during maximum in the visual light curve may be attributed to these interactions.

  11. Connecting Satellite Observations with Water Cycle Variables Through Land Data Assimilation: Examples Using the NASA GEOS-5 LDAS

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf H.; De Lannoy, Gabrielle J. M.; Forman, Barton A.; Draper, Clara S.; Liu, Qing

    2013-01-01

    A land data assimilation system (LDAS) can merge satellite observations (or retrievals) of land surface hydrological conditions, including soil moisture, snow, and terrestrial water storage (TWS), into a numerical model of land surface processes. In theory, the output from such a system is superior to estimates based on the observations or the model alone, thereby enhancing our ability to understand, monitor, and predict key elements of the terrestrial water cycle. In practice, however, satellite observations do not correspond directly to the water cycle variables of interest. The present paper addresses various aspects of this seeming mismatch using examples drawn from recent research with the ensemble-based NASA GEOS-5 LDAS. These aspects include (1) the assimilation of coarse-scale observations into higher-resolution land surface models, (2) the partitioning of satellite observations (such as TWS retrievals) into their constituent water cycle components, (3) the forward modeling of microwave brightness temperatures over land for radiance-based soil moisture and snow assimilation, and (4) the selection of the most relevant types of observations for the analysis of a specific water cycle variable that is not observed (such as root zone soil moisture). The solution to these challenges involves the careful construction of an observation operator that maps from the land surface model variables of interest to the space of the assimilated observations.

  12. Effect of LEO cycling on 125 Ah advanced design IPV nickel-hydrogen flight cells. An update

    NASA Technical Reports Server (NTRS)

    Smithrick, John J.; Hall, Stephen W.

    1991-01-01

    Validation testing of the NASA Lewis 125 Ah advanced design individual pressure vessel (IPV) nickel-hydrogen flight cells was conducted. Work consisted of characterization, storage, and cycle life testing. There was no capacity degradation after 52 days of storage with the cells in the discharged state, an open circuit, 0 C, and a hydrogen pressure of 14.5 psia. The catalyzed wall wick cells were cycled for over 11,000 cycles with no cell failures in the continuing test. One of the noncatalyzed wall wick cells failed.

  13. Recent variability in the hydrological cycle of tropical Asia from oxygen isotopes of tree cellulose

    NASA Astrophysics Data System (ADS)

    Zhu, Mengfan

    This dissertation investigates hydrological variability within tropical Asia over the past several few centuries as reflected in the stable oxygen isotope composition of atmospheric moisture. High-resolution water isotope records are developed from trees collected from northern Thailand, southern Cambodia, and eastern part of the Tibetan Plateau. These records are examined to assess whether and how the 20th century is unique in terms of the hydrological conditions in tropical Asia under the influences of both monsoon and ENSO with the observed temperature changes. In northern Thailand, the oxygen isotopic composition (δ 18O) of tree cellulose samples of Pinus kesiya from a montane forest has been analyzed in subannual resolution for the past 80 years. The cellulose δ18O values exhibit a distinctive annual cycle with an amplitude of up to 12 ‰, which is interpreted to reflect primarily the seasonal cycle of precipitation δ18 O. The cellulose δ18O annual mean values correlate significantly with the amount of summer monsoon precipitation over the India subcontinent, corroborating recent studies that suggest the so-called "isotope amount effect" in the tropical precipitation δ18O reflects the hydrological processes of the upstream or the moisture source regions instead of the rainfall amount at the local site. No obvious trend in the summer monsoon precipitation is detected from the cellulose δ 18O record. However, the record does suggest a temporal weakening relationship between the Indian Monsoon and ENSO over the 20th century. The annual maxima in the cellulose δ18O values are representative of the moisture balance during the winter dry season, and possibly document a decreasing trend in the isotopically-distinct fog water input during the dry season because of the warming in the 20th century. Isotope chronologies of Pinus merkusii from a coastal lowland forest in Cambodia have been generated to investigate hydrological variability over the Indo

  14. Enterprise SRS: Leveraging Ongoing Operations To Advance Nuclear Fuel Cycles Research And Development Programs

    SciTech Connect

    Murray, Alice M.; Marra, John E.; Wilmarth, William R.; Mcguire, Patrick W.; Wheeler, Vickie B.

    2013-07-03

    assets will continue to accomplish DOE's critical nuclear material missions (e.g., processing in H-Canyon and plutonium storage in K-Area). Thus, the demonstration can be accomplished by leveraging the incremental cost of performing demonstrations without needing to cover the full operational cost of the facility. Current Center activities have been focused on integrating advanced safeguards monitoring technologies demonstrations into the SRS H-Canyon and advanced location technologies demonstrations into K-Area Materials Storage. These demonstrations are providing valuable information to researchers and customers as well as providing the Center with an improved protocol for demonstration management that can be exercised across the entire SRS (as well as to offsite venues) so that future demonstrations can be done more efficiently and provide an opportunity to utilize these unique assets for multiple purposes involving national laboratories, academia, and commercial entities. Key among the envisioned future demonstrations is the use of H-Canyon to demonstrate new nuclear materials separations technologies critical for advancing the mission needs DOE-Nuclear Energy (DOE-NE) to advance the research for next generation fuel cycle technologies. The concept is to install processing equipment on frames. The frames are then positioned into an H-Canyon cell and testing in a relevant radiological environment involving prototypic radioactive materials can be performed.

  15. Diurnal Cycle Variability of Rainfall Over the Indian Region: Perspectives From the TRMM Satellite

    NASA Astrophysics Data System (ADS)

    Sahany, S.; Venugopal, V.; Nanjundiah, R. S.

    2008-12-01

    Using the TRMM 3-hourly, 0.25x0.25 degree 3B42 rainfall product for nine years (1999-2007), we characterise the summer season (JJAS) diurnal cycle of rainfall over the Indian land and its neighbouring oceans (10S to 35N, 60E to 100E). Most previous studies have provided an analysis of a single or few years of satellite- or station-based rainfall data (e.g., Basu, 2007; Yang and Smith, 2006; Nesbitt and Zipser, 2003) and, to our knowledge, this is one of the first studies that aims to exhaustively characterise the diurnal scale statistical characteristics of rainfall over the Indian and surrounding regions. Using harmonic analysis, we extract, at each grid point, every year, the signal corresponding to time periods smaller than 1 day, i.e., the signal that relates to diurnal and sub-diurnal variability. Subsequently, the time of rainfall peak for this filtered signal, referred to as the "peak hour," is estimated, with care taken to eliminate spurious peaks arising out of Gibbs oscillations. Our analysis suggests that the mode of the peak hour (of the diurnal-scale rainfall) over a significant part of Indian land is at 12 UTC (i.e. 5:30PM local time), a finding similar to that reported in previous studies (e.g., Liu and Zipser, 2008; Krishnamurti and Kishtawal, 2000). The Himalayan foothills were found to have a mode of peak hour at 21 UTC (i.e. 2:30AM local time), whereas over the Burmese mountains the rainfall peaks at 9 to 12 UTC (i.e. 3:30 PM to 6:30 PM local time). In addition, over the Bay of Bengal, there is a stratified spatial structure of mode of the peak hour of diurnal rainfall at 6, 9 and 12 UTC from North central to South Bay. This finding, not reported before, could be seen to be consistent with southward propagation of the diurnal rainfall pattern (e.g., Hoyos and Webster, 2007; Zuidema, 2003). We also find that the Arabian sea (to the east of 65E and north of the Equator, along a region where it rains for more than 50% of the time) shows a peak hour

  16. Arctic sea-ice melting: Effects on hydroclimatic variability and on UV-induced carbon cycling

    NASA Astrophysics Data System (ADS)

    Sulzberger, Barbara

    2016-04-01

    change on biogeochemical cycling: interactions and feedbacks, Photochemical & Photobiological Sciences, 14(1), 127-148. Francis, J. A., S. J. Vavrus (2012), Evidence linking Arctic amplification to extreme weather in mid-latitudes, Geophysical Research Letters, 39, doi: 10.1029/2012GL051000. Haaland, S., D. Hongve, H. Laudon, G. Riise, R. D. Vogt (2010), Quantifying the drivers of the increasing colored organic matter in boreal surface waters, Environmental Science & Technology, 44(8), 2975-2980. IPCC Climate Change 2013 - The Physical Science Bases (2013). Schubert, S., H. Wang, M. Suarez (2011), Warm season subseasonal variability and climate extremes in the Northern Hemisphere: The role of stationary Rossby waves, Journal of Climate, 24(18), 4773-4792. Screen, J. A. (2013), Influence of Arctic sea ice on European summer precipitation, Environmental Research Letters, 8(4), doi: 10.1088/1748-9326/8/4/044015. Sulzberger, B., E. Durisch-Kaiser (2009), Chemical characterization of dissolved organic matter (DOM): A prerequisite for understanding UV-induced changes of DOM absorption properties and bioavailability, Aquatic Sciences, 71(2), 104-126.

  17. Experimental aerodynamic and acoustic model testing of the Variable Cycle Engine (VCE) testbed coannular exhaust nozzle system: Comprehensive data report

    NASA Technical Reports Server (NTRS)

    Nelson, D. P.; Morris, P. M.

    1980-01-01

    The component detail design drawings of the one sixth scale model of the variable cycle engine testbed demonstrator exhaust syatem tested are presented. Also provided are the basic acoustic and aerodynamic data acquired during the experimental model tests. The model drawings, an index to the acoustic data, an index to the aerodynamic data, tabulated and graphical acoustic data, and the tabulated aerodynamic data and graphs are discussed.

  18. Increased winter soil temperature variability enhances nitrogen cycling and soil biotic activity in temperate heathland and grassland mesocosms

    NASA Astrophysics Data System (ADS)

    Schuerings, J.; Jentsch, A.; Hammerl, V.; Lenz, K.; Henry, H. A. L.; Malyshev, A. V.; Kreyling, J.

    2014-12-01

    Winter air temperatures are projected to increase in the temperate zone, whereas snow cover is projected to decrease, leading to increased soil temperature variability, and potentially to changes in nutrient cycling. Here, we experimentally evaluated the effects of increased winter soil temperature variability on selected aspects of the N-cycle in mesocosms containing different plant community compositions. The experiment was replicated at two sites, a colder mountainous upland site with high snow accumulation and a warmer and drier lowland site. Increased soil temperature variability enhanced soil biotic activity for both sites during winter, as indicated by 35% higher nitrogen (N) availability in the soil solution, 40% higher belowground decomposition and a 25% increase in the potential activity of the enzyme cellobiohydrolase. The mobilization of N differed between sites, and the 15N signal in leaves was reduced by 31% in response to winter warming pulses, but only at the cold site, with significant reductions occurring for three of four tested plant species at this site. Furthermore, there was a trend of increased N leaching in response to the recurrent winter warming pulses. Overall, projected winter climate change in the temperate zone, with less snow and more variable soil temperatures, appears important for shifts in ecosystem functioning (i.e. nutrient cycling). While the effects of warming pulses on plant N mobilization did not differ among sites, reduced plant 15N incorporation at the colder temperate site suggests that frost damage may reduce plant N uptake in a warmer world, with important implications for nitrogen cycling and nitrogen losses from ecosystems.

  19. The variable pressure supercritical Rankine cycle for integrated natural gas and power production from the geopressured geothermal resource

    NASA Astrophysics Data System (ADS)

    Goldsberry, F. L.

    1982-03-01

    A small-scale power plant cycle that utilizes both a variable pressure vaporizer (heater) and a floating pressure (and temperature) air-cooled condenser is described. Further, it defends this choice on the basis of classical thermodynamics and minimum capital cost by supporting these conclusions with actual comparative examples. The application suggested is for the geopressured geothermal resource. The arguments cited in this application apply to any process (petrochemical, nuclear, etc.) involving waste heat recovery.

  20. Continued Development of the Rapid Cycle Amine (RCA) System for Advanced Extravehicular Activity Systems

    NASA Technical Reports Server (NTRS)

    Papale, William; Chullen, Cinda; Campbell, Colin; Conger, Bruce; McMillin, Summer; Jeng, Frank

    2014-01-01

    Development activities related to the Rapid Cycle Amine (RCA) Carbon Dioxide (CO2) and Humidity control system have progressed to the point of integrating the RCA into an advanced Primary Life Support System (PLSS 2.0) to evaluate the interaction of the RCA among other PLSS components in a ground test environment. The RCA 2.0 assembly (integrated into PLSS 2.0) consists of a valve assembly with commercial actuator motor, a sorbent canister, and a field-programmable gate array (FPGA)-based process node controller. Continued design and development activities for RCA 3.0 have been aimed at optimizing the canister size and incorporating greater fidelity in the valve actuator motor and valve position feedback design. Further, the RCA process node controller is envisioned to incorporate a higher degree of functionality to support a distributed PLSS control architecture. This paper will describe the progression of technology readiness levels of RCA 1.0, 2.0 and 3.0 along with a review of the design and manufacturing successes and challenges for 2.0 and 3.0 units. The anticipated interfaces and interactions with the PLSS 2.0/2.5/3.0 assemblies will also be discussed.

  1. Maintaining Adequate CO2 Washout for an Advanced EMU via a New Rapid Cycle Amine Technology

    NASA Technical Reports Server (NTRS)

    Chullen, Cinda; Conger, Bruce

    2012-01-01

    Over the past several years, NASA has realized tremendous progress in Extravehicular Activity (EVA) technology development. This has been evidenced by the progressive development of a new Rapid Cycle Amine (RCA) system for the Advanced Extravehicular Mobility Unit (AEMU) Portable Life Support Subsystem (PLSS). The PLSS is responsible for the life support of the crew member in the spacesuit. The RCA technology is responsible for carbon dioxide (CO2) and humidity control. Another aspect of the RCA is that it is on-back vacuum-regenerable, efficient, and reliable. The RCA also simplifies the PLSS schematic by eliminating the need for a condensing heat exchanger for humidity control in the current EMU. As development progresses on the RCA, it is important that the sizing be optimized so that the demand on the PLSS battery is minimized. As well, maintaining the CO2 washout at adequate levels during an EVA is an absolute requirement of the RCA and associated ventilation system. Testing has been underway in-house at NASA Johnson Space Center and analysis has been initiated to evaluate whether the technology provides exemplary performance in ensuring that the CO2 is removed sufficiently and the ventilation flow is adequate for maintaining CO2 washout in the AEMU spacesuit helmet of the crew member during an EVA. This paper will review the recent developments of the RCA unit, testing planned in-house with a spacesuit simulator, and the associated analytical work along with insights from the medical aspect on the testing. 1

  2. Waste Classification based on Waste Form Heat Generation in Advanced Nuclear Fuel Cycles Using the Fuel-Cycle Integration and Tradeoffs (FIT) Model

    SciTech Connect

    Denia Djokic; Steven J. Piet; Layne F. Pincock; Nick R. Soelberg

    2013-02-01

    This study explores the impact of wastes generated from potential future fuel cycles and the issues presented by classifying these under current classification criteria, and discusses the possibility of a comprehensive and consistent characteristics-based classification framework based on new waste streams created from advanced fuel cycles. A static mass flow model, Fuel-Cycle Integration and Tradeoffs (FIT), was used to calculate the composition of waste streams resulting from different nuclear fuel cycle choices. This analysis focuses on the impact of waste form heat load on waste classification practices, although classifying by metrics of radiotoxicity, mass, and volume is also possible. The value of separation of heat-generating fission products and actinides in different fuel cycles is discussed. It was shown that the benefits of reducing the short-term fission-product heat load of waste destined for geologic disposal are neglected under the current source-based radioactive waste classification system , and that it is useful to classify waste streams based on how favorable the impact of interim storage is in increasing repository capacity.

  3. Waste Classification based on Waste Form Heat Generation in Advanced Nuclear Fuel Cycles Using the Fuel-Cycle Integration and Tradeoffs (FIT) Model - 13413

    SciTech Connect

    Djokic, Denia; Piet, Steven J.; Pincock, Layne F.; Soelberg, Nick R.

    2013-07-01

    This study explores the impact of wastes generated from potential future fuel cycles and the issues presented by classifying these under current classification criteria, and discusses the possibility of a comprehensive and consistent characteristics-based classification framework based on new waste streams created from advanced fuel cycles. A static mass flow model, Fuel-Cycle Integration and Tradeoffs (FIT), was used to calculate the composition of waste streams resulting from different nuclear fuel cycle choices. This analysis focuses on the impact of waste form heat load on waste classification practices, although classifying by metrics of radiotoxicity, mass, and volume is also possible. The value of separation of heat-generating fission products and actinides in different fuel cycles is discussed. It was shown that the benefits of reducing the short-term fission-product heat load of waste destined for geologic disposal are neglected under the current source-based radioactive waste classification system, and that it is useful to classify waste streams based on how favorable the impact of interim storage is in increasing repository capacity. (authors)

  4. Variable localization” in an ensemble Kalman filter: Application to the carbon cycle data assimilation

    NASA Astrophysics Data System (ADS)

    Kang, Ji-Sun; Kalnay, Eugenia; Liu, Junjie; Fung, Inez; Miyoshi, Takemasa; Ide, Kayo

    2011-05-01

    In ensemble Kalman filter, space localization is used to reduce the impact of long-distance sampling errors in the ensemble estimation of the forecast error covariance. When two variables are not physically correlated, their error covariance is still estimated by the ensemble and, therefore, it is dominated by sampling errors. We introduce a "variable localization" method, zeroing out such covariances between unrelated variables to the problem of assimilating carbon dioxide concentrations into a dynamical model using the local ensemble transform Kalman filter (LETKF) in an observing system simulation experiments (OSSE) framework. A system where meteorological and carbon variables are simultaneously assimilated is used to estimate surface carbon fluxes that are not directly observed. A range of covariance structures are explored for the LETKF, with emphasis on configurations allowing nonzero error covariance between carbon variables and the wind field, which affects transport of atmospheric CO2, but not between CO2 and the other meteorological variables. Such variable localization scheme zeroes out the background error covariance among prognostic variables that are not physically related, thus reducing sampling errors. Results from the identical twin experiments show that the performance in the estimation of surface carbon fluxes obtained using variable localization is much better than that using a standard full covariance approach. The relative improvement increases when the surface fluxes change with time and model error becomes significant.

  5. Advances in Urea cycle Neuroimaging: Proceedings from the 4th International symposium on Urea cycle disorders, Barcelona, Spain, September 2013

    PubMed Central

    Pacheco-Colon, Ileana; Fricke, Stanley; VanMeter, John; Gropman, M.D.

    2014-01-01

    Our previous imaging research performed as part of a Urea Cycle Rare Disorders Consortium (UCRDC) grant, has identified specific biomarkers of neurologic injury in ornithine transcarbamylase deficiency, OTCD. While characterization of mutations can be achieved in most cases, this information does not necessarily predict the severity of the underlying neurological syndrome. The biochemical consequences of any mutation may be modified additionally by a large number of factors, including contributions of other enzymes and transport systems that mediate flux through the urea cycle, diet and other environmental factors. These factors likely vary from one patient to another, and they give rise to heterogeneity of clinical severity. Affected cognitive domains include non-verbal learning, fine motor processing, reaction time, visual memory, attention, and executive function. Deficits in these capacities may be seen in symptomatic patients, as well as asymptomatic carriers with normal IQ and correlate with variances in brain structure and function in these patients. Using neuroimaging we can identify biomarkers that reflect the downstream impact of UCDs on cognition. This manuscript is a summary of the presentation from the 4th International Consortium on Urea cycle disorders held in, Barcelona, Spain, September 2, 2014. PMID:25066103

  6. Enterprise SRS: Leveraging Ongoing Operations to Advance Nuclear Fuel Cycle Programs - 12579

    SciTech Connect

    Marra, J.E.; Griffin, J.C.; Murray, A.M.; Wilmarth, W.R.

    2012-07-01

    The international leadership in nuclear technology development and deployment long held by the United States has eroded due to the lack of clear national strategies for advanced reactor fuel cycle concepts and for nuclear materials management, as well as to the recent policy decision that halts work on the nuclear fuel repository at Yucca Mountain. Although no national consensus on strategy has yet been reached, a number of recent high-profile reviews and workshops have clearly highlighted a national need for robust research, development and deployment (RD and D) programs in key areas of nuclear technology, especially nuclear separations science and engineering. Collectively, these reviews and workshops provide a picture of the nuclear separations mission needs for three major program offices: Department of Energy Office of-Environmental Management), DOE Office of Nuclear Energy), and the National Nuclear Security Administration (NNSA). While the individual program needs differ significantly in detail and timing, they share common needs in two critical areas of RD and D: - The need for access to and use of multi-purpose engineering-scale demonstration test facilities that can support testing with radioactive material, and - The need for collaborative research enterprises that encompass government research organizations (i.e., national laboratories), commercial industry and the academic community. Such collaborative enterprises effectively integrate theory and modeling with the actual experimental work at all scales, as well as strengthen the technical foundation for research in critical areas. The arguments for engineering-scale collaborative research facilities are compelling. Processing history has shown that test programs and demonstrations conducted with actual nuclear materials are essential to program success. It is widely recognized, however, that such facilities are expensive to build and maintain; creating an imposing, if not prohibitive, financial burden

  7. Inter-individual variability of forces and modular muscle coordination in cycling: a study on untrained subjects.

    PubMed

    De Marchis, Cristiano; Schmid, Maurizio; Bibbo, Daniele; Bernabucci, Ivan; Conforto, Silvia

    2013-12-01

    The aim of this study was to investigate the muscle coordination underlying pedaling in untrained subjects by using the muscle synergies paradigm, and to connect it with the inter-individual variability of EMG patterns and applied forces. Nine subjects performed a pedaling exercise on a cycle-simulator. Applied forces were recorded by means of instrumented pedals able to measure two force components. EMG signals were recorded from eight muscles of the dominant leg, and Nonnegative Matrix Factorization was applied to extract muscle synergy vectors W and time-varying activation coefficients H. Inter-individual variability was assessed for EMG patterns, force profiles, and H. Four modules were sufficient to reconstruct the muscle activation repertoire for all the subjects (variance accounted for >90% for each muscle). These modules were found to be highly similar between subjects in terms of W (mean r=.89), while most of the variability in force profiles and EMG patterns was reflected, in the muscle synergy structure, in the variability of H. These four modules have a functional interpretation when related to force distribution along the pedaling cycle, and the structure of W is shared with that present in human walking, suggesting the existence of a modular motor control in humans. PMID:24060224

  8. Causes of daily cycle variability of atmospheric pollutants in a western Mediterranean urban site (DAURE campaign)

    NASA Astrophysics Data System (ADS)

    Reche, Cristina; Moreno, Teresa; Viana, Mar; Querol, Xavier; Alastuey, Andrés.; Jimenez, Jose L.; Pandolfi, Marco; Amato, Fulvio; Pérez, Noemí; Moreno, Natalia

    2010-05-01

    The 2009 DAURE Aerosol Campaign (23-February-2009 to 27-March-2009 and 1-July to 31-July) (see Presentation: Pandolfi et al., section AS3.2) had the objective of characterising the main sources and chemical processes controlling atmospheric pollution due to particulate matter in the Mediterranean site of Barcelona (Spain). An urban and a rural background site were selected in order to describe both kinds of pollution setting. Several parameters were taken into consideration, including the variability of mass concentration in the coarse and fine fractions, particle number, amount of black carbon and the concentration of gaseous pollutants (SO2, H2S, NO, NO2, CO, O3) present. Comparisons between the chemical composition of ambient atmospheric particles during day versus night were made using twelve-hour PM samples. The data shown here are focused on results obtained for the urban site where two main atmospheric settings were distinguishable in winter, namely Atlantic advection versus local air mass recirculation. During the warmer months Saharan dust intrusions added a third important influence on PM background. The data demonstrate that superimposed upon these background influences on city air quality are important local contributions from road traffic, construction-demolition works and shipping. There is also a major local contribution of secondary aerosols, with elevated number of particles occurring at midday (and especially in summer) when nucleation processes are favoured by photochemistry. Concentrations of SO2 peak at different times to the other gaseous pollutants due to regular daytime onshore south-easterly breezes bringing harbour emissions into the city. Road traffic in Barcelona also has a great impact on air quality, as demonstrated by daily and weekly cycles of gaseous pollutants, black carbon and the finer fraction of PM, with peaks being coincident with traffic rush-hours (8-10h and 20-22h), levels of pollution increasing from Monday to Friday, and

  9. Effects of the Menstrual Cycle on Lung Function Variables in Women with Asthma

    PubMed Central

    Farha, Samar; Asosingh, Kewal; Laskowski, Daniel; Hammel, Jeffrey; Dweik, Raed A.; Wiedemann, Herbert P.; Erzurum, Serpil C.

    2009-01-01

    Rationale: Angiogenesis is a defining pathologic feature of airway remodeling and contributes to asthma severity. Women experience changes in asthma control over the menstrual cycle, a time when vessels routinely form and regress under the control of angiogenic factors. One vital function modulated over the menstrual cycle in healthy women is gas transfer, and this has been related to angiogenesis and cyclic expansion of the pulmonary vascular bed. Objectives: We hypothesized that changes in gas transfer and the pulmonary vascular bed occur in women with asthma over the menstrual cycle and are associated with worsening airflow obstruction. Methods: Twenty-three women, 13 with asthma and 10 healthy control subjects, were evaluated over the menstrual cycle with weekly measures of spirometry, gas transfer, nitric oxide, hemoglobin, factors affecting hemoglobin binding affinity, and proangiogenic factors. Measurements and Main Results: Airflow and lung diffusing capacity varied over the menstrual cycle with peak levels during menses that subsequently declined to nadir in early luteal phase. In contrast to healthy women, changes in lung diffusing capacity (DlCO) were associated with changes in membrane diffusing capacity and DlCO was not related to proangiogenic factors. DlCO did not differ between the two groups, although methemoglobin and carboxyhemoglobin were higher in women with asthma than in healthy women. Conclusions: Women with asthma experience cyclic changes in airflow as well as gas transfer and membrane diffusing capacity supportive of a hormonal effect on lung function. PMID:19520904

  10. Maxillomandibular Advancement in Obstructive Sleep Apnea Syndrome Patients: a Restrospective Study on the Sagittal Cephalometric Variables

    PubMed Central

    Ronchi, Paolo; Ambrosoli, Alessandro; Caprioglio, Alberto

    2013-01-01

    ABSTRACT Objectives The present retrospective study analyzes sagittal cephalometric changes in patients affected by obstructive sleep apnea syndrome submitted to maxillomandubular advancement. Material and Methods 15 adult sleep apnea syndrome (OSAS) patients diagnosed by polysomnography (PSG) and treated with maxillomandubular advancement (MMA) were included in this study. Pre- (T1) and postsurgical (T2) PSG studies assessing the apnea/hypopnea index (AHI) and the lowest oxygen saturation (LSAT) level were compared. Lateral cephalometric radiographs at T1 and T2 measuring sagittal cephalometric variables (SNA, SNB, and ANB) were analyzed, as were the amount of maxillary and mandibular advancement (Co-A and Co-Pog), the distance from the mandibular plane to the most anterior point of the hyoid bone (Mp-H), and the posterior airway space (PAS). Results Postoperatively, the overall mean AHI dropped from 58.7 ± 16 to 8.1 ± 7.8 events per hour (P < 0.001). The mean preoperative LSAT increased from 71% preoperatively to 90% after surgery (P < 0.001). All the patients in our study were successfully treated (AHI < 20 or reduced by 50%). Cephalometric analysis performed after surgery showed a statistically significant correlation between the mean SNA variation and the decrease in the AHI (P = 0.01). The overall mean SNA increase was 6°. Conclusions Our findings suggest that the improvement observed in the respiratory symptoms, namely the apnea/hypopnea episodes, is correlated with the SNA increase after surgery. This finding may help maxillofacial surgeons to establish selective criteria for the surgical approach to sleep apnea syndrome patients. PMID:24422033

  11. Statistically Optimal Approximations of Astronomical Signals: Implications to Classification and Advanced Study of Variable Stars

    NASA Astrophysics Data System (ADS)

    Andronov, I. L.; Chinarova, L. L.; Kudashkina, L. S.; Marsakova, V. I.; Tkachenko, M. G.

    2016-06-01

    We have elaborated a set of new algorithms and programs for advanced time series analysis of (generally) multi-component multi-channel observations with irregularly spaced times of observations, which is a common case for large photometric surveys. Previous self-review on these methods for periodogram, scalegram, wavelet, autocorrelation analysis as well as on "running" or "sub-interval" local approximations were self-reviewed in (2003ASPC..292..391A). For an approximation of the phase light curves of nearly-periodic pulsating stars, we use a Trigonometric Polynomial (TP) fit of the statistically optimal degree and initial period improvement using differential corrections (1994OAP.....7...49A). For the determination of parameters of "characteristic points" (minima, maxima, crossings of some constant value etc.) we use a set of methods self-reviewed in 2005ASPC..335...37A, Results of the analysis of the catalogs compiled using these programs are presented in 2014AASP....4....3A. For more complicated signals, we use "phenomenological approximations" with "special shapes" based on functions defined on sub-intervals rather on the complete interval. E. g. for the Algol-type stars we developed the NAV ("New Algol Variable") algorithm (2012Ap.....55..536A, 2012arXiv1212.6707A, 2015JASS...32..127A), which was compared to common methods of Trigonometric Polynomial Fit (TP) or local Algebraic Polynomial (A) fit of a fixed or (alternately) statistically optimal degree. The method allows determine the minimal set of parameters required for the "General Catalogue of Variable Stars", as well as an extended set of phenomenological and astrophysical parameters which may be used for the classification. Totally more that 1900 variable stars were studied in our group using these methods in a frame of the "Inter-Longitude Astronomy" campaign (2010OAP....23....8A) and the "Ukrainian Virtual Observatory" project (2012KPCB...28...85V).

  12. Renovation of CPF (Chemical Processing Facility) for Development of Advanced Fast Reactor Fuel Cycle System

    SciTech Connect

    Shinichi Aose; Takafumi Kitajima; Kouji Ogasawara; Kazunori Nomura; Shigehiko Miyachi; Yoshiaki Ichige; Tadahiro Shinozaki; Shinichi Ohuchi

    2008-01-15

    system. The in-cell crane in CA-5 was renovated to increase driving efficiency. At the renovation for the in-cell crane, full scale mockup test and 3D simulation test had been executed in advance. After the renovation, hot tests in the CPF had been resumed from JFY 2002. New equipments such as dissolver, extractor, electrolytic device, etc. were installed in CA-3 conformably to the new design laid out in order to ensure the function and space. Glove boxes in the analysis laboratory were renewed in order to let it have flexibility from the viewpoint of conducting basic experiments (ex. U crystallization). Glove boxes and hoods were newly installed in the laboratory A for basic research and analysis, especially on MA chemistries. One laboratory (the laboratory C) was established to research about dry reprocessing. The renovation of the CPF has been executed in order to contribute to the development on the advanced fast reactor fuel cycle system, which will give us many sort of technical subject and experimental theme to be solved in the 2. Generation of the CPF.

  13. Maintaining Adequate CO2 Washout for an Advanced EMU via a New Rapid Cycle Amine Technology

    NASA Technical Reports Server (NTRS)

    Chullen, Cinda

    2011-01-01

    Over the past several years, NASA has realized tremendous progress in Extravehicular Activity (EVA) technology development. This has been evidenced by the progressive development of a new Rapic Cycle Amine (RCA) system for the Advanced Extravehicular Mobility Unit (AEMU) Portable Life Support Subsystem (PLSS). The PLSS is responsible for the life support of the crew member in the spacesuit. The RCA technology is responsible for carbon dioxide (CO2) and humidity control. Another aspect of the RCA is that it is on-back vacuum-regenerable, efficient, and reliable. The RCA also simplifies the PLSS schematic by eliminating the need for a condensing heat exchanger for humidity control in the current EMU. As development progresses on the RCA, it is important that the sizing be optimized so that the demand on the PLSS battery is minimized. As well, maintaining the CO2 washout at adequate levels during an EVA is an absolute requirement of the RCA and associated ventilation system. Testing has been underway in-house at NASA Johnson Space Center and analysis has been initiated to evaluate whether the technology provides exemplary performance in ensuring that the CO2 is removed sufficiently enough and the ventilation flow is adequate enough to maintain CO2 1 Project Engineer, Space Suit and Crew Survival Systems Branch, Crew and Thermal Systems Division, 2101 NASA Parkway, Houston, TX 77058/EC5. washout in the AEMU spacesuit helmet of the crew member during an EVA. This paper will review the recent developments of the RCA unit, the testing results performed in-house with a spacesuit simulator, and the associated analytical work along with insights from the medical aspect on the testing.

  14. Development of Advanced Life Cycle Costing Methods for Technology Benefit/Cost/Risk Assessment

    NASA Technical Reports Server (NTRS)

    Yackovetsky, Robert (Technical Monitor)

    2002-01-01

    The overall objective of this three-year grant is to provide NASA Langley's System Analysis Branch with improved affordability tools and methods based on probabilistic cost assessment techniques. In order to accomplish this objective, the Aerospace Systems Design Laboratory (ASDL) needs to pursue more detailed affordability, technology impact, and risk prediction methods and to demonstrate them on variety of advanced commercial transports. The affordability assessment, which is a cornerstone of ASDL methods, relies on the Aircraft Life Cycle Cost Analysis (ALCCA) program originally developed by NASA Ames Research Center and enhanced by ASDL. This grant proposed to improve ALCCA in support of the project objective by updating the research, design, test, and evaluation cost module, as well as the engine development cost module. Investigations into enhancements to ALCCA include improved engine development cost, process based costing, supportability cost, and system reliability with airline loss of revenue for system downtime. A probabilistic, stand-alone version of ALCCA/FLOPS will also be developed under this grant in order to capture the uncertainty involved in technology assessments. FLOPS (FLight Optimization System program) is an aircraft synthesis and sizing code developed by NASA Langley Research Center. This probabilistic version of the coupled program will be used within a Technology Impact Forecasting (TIF) method to determine what types of technologies would have to be infused in a system in order to meet customer requirements. A probabilistic analysis of the CER's (cost estimating relationships) within ALCCA will also be carried out under this contract in order to gain some insight as to the most influential costs and the impact that code fidelity could have on future RDS (Robust Design Simulation) studies.

  15. Advanced Fuel Cycle Initiative AFC-1D, AFC-1G and AFC-1H Irradiation Report

    SciTech Connect

    Debra J. Utterbeck; Gray Chang

    2005-09-01

    The U. S. Advanced Fuel Cycle Initiative (AFCI) seeks to develop and demonstrate the technologies needed to transmute the long-lived transuranic actinide isotopes contained in spent nuclear fuel into shorter-lived fission products, thereby dramatically decreasing the volume of material requiring disposition and the long-term radiotoxity and heat load of high-level waste sent to a geologic repository. The AFC-1 irradiation experiments on transmutation fuels are expected to provide irradiation performance data on non-fertile and low-fertile fuel forms specifically, irradiation growth and swelling, helium production, fission gas release, fission product and fuel constituent migration, fuel phase equilibria, and fuel-cladding chemical interaction. Contained in this report are the to-date physics evaluations performed on three of the AFC-1 experiments; AFC-1D, AFC-1G and AFC-1H. The AFC-1D irradiation experiment consists of metallic non-fertile fuel compositions with minor actinides for potential use in accelerator driven systems and AFC-1G and AFC-1H irradiation experiments are part of the fast neutron reactor fuel development effort. These experiments are high burnup analogs to previously irradiated experiments and are to be irradiated to = 20 atom % burnup. Results of the evaluations show that AFC-1D will remain in the ATR for approximately 100 additional effective full power days (EFPDs), and AFC-1G and AFC-1H for approximately 300 additional EFPDs in order to reach the desired programmatic burnup. The specific irradiation schedule for these tests will be determined based on future physics evaluations and all results will be documented in subsequent reports.

  16. Radioactive Waste Partitioning and Transmutation within Advanced Fuel Cycles: Achievements and Challenges

    SciTech Connect

    M. Salvatores; G. Palmiotti

    2011-01-01

    If nuclear power should become a sustainable source of energy, a safe, robust and acceptable solution must be pursued for existing and projected inventories of high-activity, long-lived radioactive waste. Remarkable progress in the last two decades has been made in the field of geological disposal. Some countries have reached important milestones and geological disposal (of spent fuel) is expected to start in 2020 in Finland and in 2022 in Sweden and in fact the licensing of the geological repositories in both countries is now entering into their final phases. In France disposal of Intermediate Level Wastes (ILW) and vitrified High Level Wastes (HLW) is expected to start around 2025, according to the roadmap defined by a Parliament Act in 2006. In this context, transmutation of part of the waste through use of advanced fuel cycles, probably feasible in the coming decades, has the potential of reducing the burden on the geological repository. This article presents the physical principle of transmutation and reviews several strategies of P&T (Partitioning and Transmutation). Many recent studies have demonstrated that the impact of P&T on geological disposal concepts is not overwhelmingly high. However, by reducing waste heat production a more efficient utilization of repository space is likely. Moreover, even if radionuclide release from the waste to the environment and related calculated doses to the population are only partially reduced by P&T, it is important to point out that a clear reduction of the actinide inventory in the High Level Waste definitely reduces risks arising from less probable evolutions of a repository, i.e. increase of actinide mobility in certain geochemical situations and radiological impact by human intrusion.

  17. Radioactive waste partitioning and transmutation within advanced fuel cycles: Achievements and challenges

    NASA Astrophysics Data System (ADS)

    Salvatores, M.; Palmiotti, G.

    2011-01-01

    If nuclear power becomes a sustainable source of energy, a safe, robust, and acceptable solution must be pursued for existing and projected inventories of high-activity, long-lived radioactive waste. Remarkable progress in the field of geological disposal has been made in the last two decades. Some countries have reached important milestones, and geological disposal (of spent fuel) is expected to start in 2020 in Finland and in 2022 in Sweden. In fact, the licensing of the geological repositories in both countries is now entering into its final phase. In France, disposal of intermediate-level waste (ILW) and vitrified high-level waste (HLW) is expected to start around 2025, according to the roadmap defined by an Act of Parliament in 2006. In this context, transmutation of part of the waste through use of advanced fuel cycles, probably feasible in the coming decades, can reduce the burden on the geological repository. This article presents the physical principle of transmutation and reviews several strategies of partitioning and transmutation (P&T). Many recent studies have demonstrated that the impact of P&T on geological disposal concepts is not overwhelmingly high. However, by reducing waste heat production, a more efficient utilization of repository space is likely. Moreover, even if radionuclide release from the waste to the environment and related calculated doses to the population are only partially reduced by P&T, it is important to point out that a clear reduction of the actinide inventory in the HLW definitely reduces risks arising from less probable evolutions of a repository (i.e., an increase of actinide mobility in certain geochemical situations and radiological impact by human intrusion).

  18. Influence of Short-Term Solar UV Variability on the Determination of Solar Cycle Minimum

    NASA Technical Reports Server (NTRS)

    Cebula, Richard P.; DeLand, Matthew T.

    1997-01-01

    Smoothing solar UV data on rotational timescale (approx. 27 days) improves identification of solar minimum. Smoothing intervals which are not multiples of rotational period (e.g. 35 days) can leave measurable residual signal. No evidence found for periodic behavior on intermediate (50-250 days) time scales during Cycle 22, based on data from three solar UV instruments.

  19. Variability of Respiration and Metabolism: Responses to Submaximal Cycling and Running.

    ERIC Educational Resources Information Center

    Armstrong, Lawrence E.; Costill, David L.

    1985-01-01

    This investigation examined day-to-day variations in metabolic measurements during submaximal running and cycling. Significant differences were found in the oxygen uptake (VO2) of runners and cyclists and the minute ventilation (VE) of cyclists while running, but blood lactic acid (HLA) did not differ day to day. (Author/MT)

  20. Reproductive cycle of Ensis magnus in the Ría de Pontevedra (NW Spain): Spatial variability and fisheries management implications

    NASA Astrophysics Data System (ADS)

    Hernández-Otero, A.; Martínez-Castro, C.; Vázquez, E.; Macho, G.

    2014-08-01

    Mesoscale differences in the reproductive cycle of the commercial sword razor clam Ensis magnus (Schumacher, 1817) were studied in six shellfish beds in the Ría de Pontevedra (NW Spain) between March 2008 and July 2010. The GCI accurately described the reproductive cycle as indicated by the histological analysis. Both methods showed that the reproductive cycle was similar at different sites and was characterized by a resting stage during summer and early autumn, initiation of gametogenesis in autumn and a period of successive spawning interspersed with gonad recovery during winter and spring. However, a 15-day to one month delay in advanced stages of gametogenesis and maturation was observed between the inner and the outermost site of the ria, as well as an extended spawning period in the outermost area. Lower bottom seawater temperatures at the outermost sites appeared to delay maturation and to prolong the spawning periods, whereas salinity fluctuations at the innermost sites appeared to reduce the length of the cycle. This study provides the first estimation of the size at which E. magnus reaches sexual maturity in the Iberian Peninsula, determined in 79 mm, and it is also the first work in determining the mesoscale variation in gonadal development of any species of the superfamily Solenoidea. The results highlight the importance of carrying out mesoscale studies of the reproductive biology in coastal fisheries resources. Some of the findings of the present study have already been applied in the rotation scheme of the fishery harvesting plan.

  1. The Lunar Nodal Cycle and the Bidecadal Climate Variability in Precipitation and Tropospheric Circulation Over Southern South America

    NASA Astrophysics Data System (ADS)

    Agosta, E.

    2013-05-01

    The present work will show for first time some statistical evidences that the lunar nodal cycle can influence the low-frequency variability of summer rainfalls in the plains to the east of subtropical Andes, a region known as 'Nuevo Cuyo' (NC) in South America. The link can be established through the sea surface temperature (SST) modulation that is induced by the nodal amplitudes of diurnal tides over the southwestern South Atlatnci (SWSA) region. In years of strong (weak) diurnal tides, nodal tide-induced diapycnical mixing makes SST cooler (warmer) that are accompanied by negative (positive) sea level pressure (SLP) anomalies affecting the mid-latitudes low-level tropospheric circulation. The SST variations would presumably affect the lower tropospheric baroclinicity in the surroundings of the Malvinas/Falklands Islands in the SWSA, which in turn would induce shifts of mid-latitude stormtracks. Tropospheric circulation anomalies being located over the SWSA directly affect the interannual variability of summer rainfalls in NC. It is further shown that such an influence can be extended to the bidecadal variability observed in the summer rainfalls owing to the nodal modulation effect. The identification of the nodal periodicity in the NC summer rainfall variability is statistically robust. Although the 1976/77 climate shift has mitigated the bidecadal component of the summer rainfalls until the early 2000s, the nodal cycle has always been present. Hence it could improve the interdecadal predictability of the mean conditions of summer rainfalls and of those socio-economic variables being sensitive to precipitation such as grape yield in the Mendoza Province.

  2. Persistent millennial-scale climate variability in the eastern tropical North Pacific over the last two glacial cycles

    NASA Astrophysics Data System (ADS)

    Arellano-Torres, Elsa; Ganeshram, Raja S.; Pichevin, Laetitia E.; Salas-de-Leon, David Alberto

    2015-06-01

    High-resolution sediment records from the eastern tropical North Pacific (ETNP) spanning the last ~240 ka B.P. were studied to document the nature of millennial-scale climatic events in the tropical Pacific and to investigate teleconnection mechanisms. We present organic carbon (%OC) and diffuse spectral reflectivity records as indicative of upwelling and productivity changes off NW Mexico over the middle to late Pleistocene. The new productivity records document the persistence of abrupt millennial-scale changes over the last two glacial cycles. Detailed spectral and wavelet time series analyses show the predominance of longer climatic cycles (2-6 ka) during the last and the penultimate glacial periods. The persistence of millennial variability during the penultimate glacial, in absence of large ice rafted debris events in the North Atlantic, suggests that freshwater input through ice sheet dynamics is not essential for millennial-scale climate variability. Given the worldwide emerging picture of remarkable similar millennial-scale records over long time periods, we suggest that the pacing of this climate variability may represent a natural resonance in the climate system, amplified by a tightly coupled oceanic and atmospheric teleconnection processes. We present a schematic scenario of millennial-scale climate change depicting the role of the tropical Pacific in this global teleconnection system by linking productivity and upwelling changes in the ETNP with shifts in the position of the Intertropical Convergence Zone and the strength of the subtropical North Pacific High.

  3. Time scales of the European surface air temperature variability: The role of the 7-8 year cycle

    NASA Astrophysics Data System (ADS)

    Jajcay, Nikola; Hlinka, Jaroslav; Kravtsov, Sergey; Tsonis, Anastasios A.; Paluš, Milan

    2016-01-01

    Air temperature variability on different time scales exhibits recurring patterns and quasi-oscillatory phenomena. Climate oscillations with the period about 7-8 years have been observed in many instrumental records in Europe. Although these oscillations are weak if considering their amplitude, they might have nonnegligible influence on temperature variability on shorter time scales due to cross-scale interactions recently observed by Paluš (2014). In order to quantify the cross-scale influence, we propose a simple conditional mean approach which estimates the effect of the cycle with the period close to 8 years on the amplitude of the annual cycle in surface air temperature (SAT) in the range 0.7-1.4°C and the effect on the overall variability of the SAT anomalies (SATA) leads to the changes 1.5-1.7°C in the annual SATA means. The strongest effect in the winter SATA means reaches 4-5°C in central European station and reanalysis data.

  4. Interannual Variability of Snow and Ice and Impact on the Carbon Cycle

    NASA Technical Reports Server (NTRS)

    Yung, Yuk L.

    2004-01-01

    The goal of this research is to assess the impact of the interannual variability in snow/ice using global satellite data sets acquired in the last two decades. This variability will be used as input to simulate the CO2 interannual variability at high latitudes using a biospheric model. The progress in the past few years is summarized as follows: 1) Albedo decrease related to spring snow retreat; 2) Observed effects of interannual summertime sea ice variations on the polar reflectance; 3) The Northern Annular Mode response to Arctic sea ice loss and the sensitivity of troposphere-stratosphere interaction; 4) The effect of Arctic warming and sea ice loss on the growing season in northern terrestrial ecosystem.

  5. Variability of radiatively forced diurnal cycle of intense convection in the tropical west pacific

    SciTech Connect

    Gray, W.M.; Sheaffer, J.D.; Thorson, W.B.

    1996-04-01

    Strong differences occur in daytime versus nighttime (DVN) net radiative cooling in clear versus cloudy areas of the tropical atmosphere. Daytime average cooling is approximately -0.7{degrees}C/day, whereas nighttime net tropospheric cooling rates are about -1.5{degrees}C/day, an approximately two-to-one difference. The comparatively strong nocturnal cooling in clear areas gives rise to a diurnally varying vertical circulation and horizontal convergence cycle. Various manifestations of this cyclic process include the observed early morning heavy rainfall maxima over the tropical oceans. The radiatively driven DVN circulation appears to strongly modulate the resulting diurnal cycle of intense convection which creates the highest, coldest cloudiness over maritime tropical areas and is likely a fundamental mechanism governing both small and large scale dynamics over much of the tropical environment.

  6. Use of Multiple Reheat Helium Brayton Cycles to Eliminate the Intermediate Heat Transfer Loop for Advanced Loop Type SFRs

    SciTech Connect

    Haihua Zhao; Hongbin Zhang; Samuel E. Bays

    2009-05-01

    The sodium intermediate heat transfer loop is used in existing sodium cooled fast reactor (SFR) plant design as a necessary safety measure to separate the radioactive primary loop sodium from the water of the steam Rankine power cycle. However, the intermediate heat transfer loop significantly increases the SFR plant cost and decreases the plant reliability due to the relatively high possibility of sodium leakage. A previous study shows that helium Brayton cycles with multiple reheat and intercooling for SFRs with reactor outlet temperature in the range of 510°C to 650°C can achieve thermal efficiencies comparable to or higher than steam cycles or recently proposed supercritical CO2 cycles. Use of inert helium as the power conversion working fluid provides major advantages over steam or CO2 by removing the requirement for safety systems to prevent and mitigate the sodium-water or sodium-CO2 reactions. A helium Brayton cycle power conversion system therefore makes the elimination of the intermediate heat transfer loop possible. This paper presents a pre-conceptual design of multiple reheat helium Brayton cycle for an advanced loop type SFR. This design widely refers the new horizontal shaft distributed PBMR helium power conversion design features. For a loop type SFR with reactor outlet temperature 550°C, the design achieves 42.4% thermal efficiency with favorable power density comparing with high temperature gas cooled reactors.

  7. Test summary for advanced H2 cycle NI-CD cell

    NASA Technical Reports Server (NTRS)

    Miller, Lee

    1987-01-01

    To improve operational tolerances and mass, the H2 gas recombination design provisions of the Ni-H2 system were incorporated into the sealed Ni-Cd system. Produced is a cell design capable of operating on the H2 cycle versus the normal O2 cycle. Three test cells have now completed approximately 4,330 LEO (90 minute) cycles at 20 percent depth of discharge (DOD). Performance remains stable although one cell exhibited a temporary pressure anomaly.

  8. Refrigerator with variable capacity compressor and cycle priming action through capacity control and associated methods

    DOEpatents

    Gomes, Alberto Regio; Litch, Andrew D.; Wu, Guolian

    2016-03-15

    A refrigerator appliance (and associated method) that includes a condenser, evaporator and a multi-capacity compressor. The appliance also includes a pressure reducing device arranged within an evaporator-condenser refrigerant circuit, and a valve system for directing or restricting refrigerant flow through the device. The appliance further includes a controller for operating the compressor upon the initiation of a compressor ON-cycle at a priming capacity above a nominal capacity for a predetermined or calculated duration.

  9. Entanglement in continuous-variable systems: recent advances and current perspectives

    NASA Astrophysics Data System (ADS)

    Adesso, Gerardo; Illuminati, Fabrizio

    2007-07-01

    We review the theory of continuous-variable entanglement with special emphasis on foundational aspects, conceptual structures and mathematical methods. Much attention is devoted to the discussion of separability criteria and entanglement properties of Gaussian states, for their great practical relevance in applications to quantum optics and quantum information, as well as for the very clean framework that they allow for the study of the structure of nonlocal correlations. We give a self-contained introduction to phase-space and symplectic methods in the study of Gaussian states of infinite-dimensional bosonic systems. We review the most important results on the separability and distillability of Gaussian states and discuss the main properties of bipartite entanglement. These include the extremal entanglement, minimal and maximal, of two-mode mixed Gaussian states, the ordering of two-mode Gaussian states according to different measures of entanglement, the unitary (reversible) localization and the scaling of bipartite entanglement in multimode Gaussian states. We then discuss recent advances in the understanding of entanglement sharing in multimode Gaussian states, including the proof of the monogamy inequality of distributed entanglement for all Gaussian states. Multipartite entanglement of Gaussian states is reviewed by discussing its qualification by different classes of separability, and the main consequences of the monogamy inequality, such as the quantification of genuine tripartite entanglement in three-mode Gaussian states, the promiscuous nature of entanglement sharing in symmetric Gaussian states and the possible coexistence of unlimited bipartite and multipartite entanglement. We finally review recent advances and discuss possible perspectives on the qualification and quantification of entanglement in non-Gaussian states, a field of research that is to a large extent yet to be explored.

  10. Inter-subject variability modulates phonological advance planning in the production of adjective-noun phrases.

    PubMed

    Michel Lange, Violaine; Laganaro, Marina

    2014-01-01

    The literature on advance phonological planning in adjective-noun phrases (NPs) presents diverging results: while many experimental studies suggest that the entire NP is encoded before articulation, other results favor a span of encoding limited to the first word. Although cross-linguistic differences in the structure of adjective-NPs may account for some of these contrasting results, divergences have been reported even among similar languages and syntactic structures. Here we examined whether inter-individual differences account for variability in the span of phonological planning in the production of French NPs, where previous results indicated encoding limited to the first word. The span of phonological encoding is tested with the picture-word interference (PWI) paradigm using phonological distractors related to the noun or to the adjective of the NPs. In Experiment 1, phonological priming effects were limited to the first word in adjective NPs whichever the position of the adjective (pre-nominal or post-nominal). Crucially, phonological priming effects on the second word interacted with speakers' production speed suggesting different encoding strategies for participants. In Experiment 2, we tested this hypothesis further with a larger group of participants. Results clearly showed that slow and fast initializing participants presented different phonological priming patterns on the last element of adjective-NPs: while the first word was primed by a distractor for all speakers, only the slow speaker group presented a priming effect on the second element of the NP. These results show that the span of phonological encoding is modulated by inter-individual strategies: in experimental paradigms some speakers plan word by word whereas others encode beyond the initial word. We suggest that the diverging results reported in the literature on advance phonological planning may partly be reconciled in light of the present results. PMID:24550866

  11. Inter-subject variability modulates phonological advance planning in the production of adjective-noun phrases

    PubMed Central

    Michel Lange, Violaine; Laganaro, Marina

    2014-01-01

    The literature on advance phonological planning in adjective-noun phrases (NPs) presents diverging results: while many experimental studies suggest that the entire NP is encoded before articulation, other results favor a span of encoding limited to the first word. Although cross-linguistic differences in the structure of adjective-NPs may account for some of these contrasting results, divergences have been reported even among similar languages and syntactic structures. Here we examined whether inter-individual differences account for variability in the span of phonological planning in the production of French NPs, where previous results indicated encoding limited to the first word. The span of phonological encoding is tested with the picture-word interference (PWI) paradigm using phonological distractors related to the noun or to the adjective of the NPs. In Experiment 1, phonological priming effects were limited to the first word in adjective NPs whichever the position of the adjective (pre-nominal or post-nominal). Crucially, phonological priming effects on the second word interacted with speakers' production speed suggesting different encoding strategies for participants. In Experiment 2, we tested this hypothesis further with a larger group of participants. Results clearly showed that slow and fast initializing participants presented different phonological priming patterns on the last element of adjective-NPs: while the first word was primed by a distractor for all speakers, only the slow speaker group presented a priming effect on the second element of the NP. These results show that the span of phonological encoding is modulated by inter-individual strategies: in experimental paradigms some speakers plan word by word whereas others encode beyond the initial word. We suggest that the diverging results reported in the literature on advance phonological planning may partly be reconciled in light of the present results. PMID:24550866

  12. The Need for Technology Maturity of Any Advanced Capability to Achieve Better Life Cycle Cost (LCC)

    NASA Technical Reports Server (NTRS)

    Robinson, John W.; Levack, Daniel J. H.; Rhodes, Russel E.; Chen, Timothy T.

    2009-01-01

    Programs such as space transportation systems are developed and deployed only rarely, and they have long development schedules and large development and life cycle costs (LCC). They have not historically had their LCC predicted well and have only had an effort to control the DDT&E phase of the programs. One of the factors driving the predictability, and thus control, of the LCC of a program is the maturity of the technologies incorporated in the program. If the technologies incorporated are less mature (as measured by their Technology Readiness Level - TRL), then the LCC not only increases but the degree of increase is difficult to predict. Consequently, new programs avoid incorporating technologies unless they are quite mature, generally TRL greater than or equal to 7 (system prototype demonstrated in a space environment) to allow better predictability of the DDT&E phase costs unless there is no alternative. On the other hand, technology development programs rarely develop technologies beyond TRL 6 (system/subsystem model or prototype demonstrated in a relevant environment). Currently the lack of development funds beyond TRL 6 and the major funding required for full scale development leave little or no funding available to prototype TRL 6 concepts so that hardware would be in the ready mode for safe, reliable and cost effective incorporation. The net effect is that each new program either incorporates little new technology or has longer development schedules and costs, and higher LCC, than planned. This paper presents methods to ensure that advanced technologies are incorporated into future programs while providing a greater accuracy of predicting their LCC. One method is having a dedicated organization to develop X-series vehicles or separate prototypes carried on other vehicles. The question of whether such an organization should be independent of NASA and/or have an independent funding source is discussed. Other methods are also discussed. How to make the

  13. Mercury cycling in aquatic ecosystems and trophic state-related variables--implications from structural equation modeling.

    PubMed

    Pollman, Curtis D

    2014-11-15

    Structural equation modeling (SEM) provides a framework that can more properly handle complex variable interactions inherent in mercury cycling and its bioaccumulation compared to more traditional regression-based methods. SEM was applied to regional data sets for three different types of aquatic ecosystems within Florida, USA--lakes, streams, and the Everglades--to evaluate the underlying nature (i.e., indirect and direct) of the relationships between fish mercury concentrations and trophic state related variables such as nutrients, dissolved organic carbon (DOC), sulfate, and alkalinity. The modeling results indicated some differences in key variable relationships--for example, the effect of nutrients on fish mercury in lakes and streams was uniformly negative through direct and indirect pathways consistent with biodilution or eutrophication-associated effects on food web structure. Somewhat surprisingly, however, was that total phosphorus did not serve as a meaningful variable in the Everglades model, apparently because its effects were masked or secondary to the effects of DOC. What is perhaps a more important result were two key similarities across the three systems. First, the modeling clearly indicates that the dominant influence on fish tissue mercury concentrations in all three systems is related to variations in the methylmercury signal. Second, the modeling demonstrated that the effect of DOC on fish mercury concentrations was exerted through multiple and antagonistic pathways, including facilitated transport of total mercury and methylmercury, enhanced rates of methylation, and limitations imposed on bioavailability. Indeed, while the individual DOC pathways in the models were all highly significant (generally p<0.001), the net effect of DOC in each model was greatly reduced or insignificant. These results can help explain contradictory results obtained previously by other researchers in other systems, and illustrate the importance of SEM as a modeling

  14. Regional Variability and Uncertainty of Electric Vehicle Life Cycle CO₂ Emissions across the United States.

    PubMed

    Tamayao, Mili-Ann M; Michalek, Jeremy J; Hendrickson, Chris; Azevedo, Inês M L

    2015-07-21

    We characterize regionally specific life cycle CO2 emissions per mile traveled for plug-in hybrid electric vehicles (PHEVs) and battery electric vehicles (BEVs) across the United States under alternative assumptions for regional electricity emission factors, regional boundaries, and charging schemes. We find that estimates based on marginal vs average grid emission factors differ by as much as 50% (using National Electricity Reliability Commission (NERC) regional boundaries). Use of state boundaries versus NERC region boundaries results in estimates that differ by as much as 120% for the same location (using average emission factors). We argue that consumption-based marginal emission factors are conceptually appropriate for evaluating the emissions implications of policies that increase electric vehicle sales or use in a region. We also examine generation-based marginal emission factors to assess robustness. Using these two estimates of NERC region marginal emission factors, we find the following: (1) delayed charging (i.e., starting at midnight) leads to higher emissions in most cases due largely to increased coal in the marginal generation mix at night; (2) the Chevrolet Volt has higher expected life cycle emissions than the Toyota Prius hybrid electric vehicle (the most efficient U.S. gasoline vehicle) across the U.S. in nearly all scenarios; (3) the Nissan Leaf BEV has lower life cycle emissions than the Prius in the western U.S. and in Texas, but the Prius has lower emissions in the northern Midwest regardless of assumed charging scheme and marginal emissions estimation method; (4) in other regions the lowest emitting vehicle depends on charge timing and emission factor estimation assumptions. PMID:26125323

  15. Solar Cycle Effects on Equatorial Electrojet Strength and Low Latitude Ionospheric Variability (P10)

    NASA Astrophysics Data System (ADS)

    Veenadhari, B.; Alex, S.

    2006-11-01

    veena_iig@yahoo.co.in The most obvious indicators of the activity of a solar cycle are sunspots, flares, plages, and soon. These are intimately linked to the solar magnetic fields, heliospheric processes which exhibit complex but systematic variations. The changes in geomagnetic activity, as observed in the ground magnetic records follow systematic correspondence with the solar activity conditions. Thus the transient variations in the magnetic field get modified by differing solar conditions. Also the solar cycle influences the Earth causing changes in geomagnetic activity, the magnetosphere and the ionosphere. Daily variations in the ground magnetic field are produced by different current systems in the earth’s space environment flowing in the ionosphere and magnetosphere which has a strong dependence on latitude and longitude of the location. The north-south (Horizontal) configuration of the earth’s magnetic field over the equator is responsible for the narrow band of current system over the equatorial latitudes and is called the Equatorial electrojet (EEJ) and is a primary driver for Equatorial Ionization anomaly (EIA). Equatorial electric fields and plasma drifts play the fundamental roles on the morphology of the low latitude ionosphere and strongly vary during geomagnetically quiet and disturbed periods. Quantitative study is done to illustrate the development process of EEJ and its influence on ionospheric parameters. An attempt is also made to examine and discuss the response of the equatorial electrojet parameters to the fast varying conditions of solar wind and interplanetary parameters.

  16. Chromatin Proteomics Reveals Variable Histone Modifications during the Life Cycle of Trypanosoma cruzi.

    PubMed

    de Jesus, Teresa Cristina Leandro; Nunes, Vinícius Santana; Lopes, Mariana de Camargo; Martil, Daiana Evelin; Iwai, Leo Kei; Moretti, Nilmar Silvio; Machado, Fabrício Castro; de Lima-Stein, Mariana L; Thiemann, Otavio Henrique; Elias, Maria Carolina; Janzen, Christian; Schenkman, Sergio; da Cunha, Julia Pinheiro Chagas

    2016-06-01

    Histones are well-conserved proteins that form the basic structure of chromatin in eukaryotes and undergo several post-translational modifications, which are important for the control of transcription, replication, DNA damage repair, and chromosome condensation. In early branched organisms, histones are less conserved and appear to contain alternative sites for modifications, which could reveal evolutionary unique functions of histone modifications in gene expression and other chromatin-based processes. Here, by using high-resolution mass spectrometry, we identified and quantified histone post-translational modifications in two life cycle stages of Trypanosoma cruzi, the protozoan parasite that causes Chagas disease. We detected 44 new modifications, namely: 18 acetylations, seven monomethylations, seven dimethylations, seven trimethylations, and four phosphorylations. We found that replicative (epimastigote stage) contains more histone modifications than nonreplicative and infective parasites (trypomastigote stage). Acetylations of lysines at the C-terminus of histone H2A and methylations of lysine 23 of histone H3 were found to be enriched in trypomastigotes. In contrast, phosphorylation in serine 23 of H2B and methylations of lysine 76 of histone H3 predominates in proliferative states. The presence of one or two methylations in the lysine 76 was found in cells undergoing mitosis and cytokinesis, typical of proliferating parasites. Our findings provide new insights into the role of histone modifications related to the control of gene expression and cell-cycle regulation in an early divergent organism. PMID:27108550

  17. Energy cycle associated with inter-member variability in a large ensemble of simulations with the Canadian RCM (CRCM5)

    NASA Astrophysics Data System (ADS)

    Nikiéma, Oumarou; Laprise, René

    2016-01-01

    In an ensemble of Regional Climate Model (RCM) simulations where different members are initialised at different times but driven by identical lateral boundary conditions, the individual members provide different, but equally acceptable, weather sequences. In others words, RCM simulations exhibit the phenomenon of Internal Variability (or inter-member variability—IV), defined as the spread between members in an ensemble of simulations. Our recent studies reveal that RCM's IV is associated with energy conversions similar to those taking place in weather systems. By analogy with the classical work on global energetics of weather systems, a formulation of an energy cycle for IV has been developed that is applicable over limited-area domains. Prognostic equations for ensemble-mean kinetic energy and available enthalpy are decomposed into contributions due to ensemble-mean variables and those due to deviations from the ensemble mean (IV). Together these equations constitute an energy cycle for IV in ensemble simulations of an RCM. A 50-member ensemble of 1-year simulations that differ only in their initial conditions was performed with the fifth-generation Canadian RCM (CRCM5) over an eastern North America domain. The various energy reservoirs of IV and exchange terms between reservoirs were evaluated; the results show a remarkably close parallel between the energy conversions associated with IV in ensemble simulations of RCM and the energy conversions taking place in weather systems in the real atmosphere.

  18. Orbit Transfer Vehicle Engine Study. Phase A, extension 1: Advanced expander cycle engine optimization

    NASA Technical Reports Server (NTRS)

    Mellish, J. A.

    1979-01-01

    The performance optimization of expander cycle engines at vacuum thrust levels of 10K, 15K, and 20K lb is discussed. The optimization is conducted for a maximum engine length with an extendible nozzle in the retracted position of 60 inches and an engine mixture ratio of 6.0:1. The thrust chamber geometry and cycle analyses are documented. In addition, the sensitivity of a recommended baseline expander cycle to component performance variations is determined and chilldown/start propellant consumptions are estimated.

  19. Advances in modeling of the bovine estrous cycle: synchronization with PGF2α.

    PubMed

    Stötzel, C; Plöntzke, J; Heuwieser, W; Röblitz, S

    2012-10-15

    Our model of the bovine estrous cycle is a set of ordinary differential equations which generates hormone profiles of successive estrous cycles with several follicular waves per cycle. It describes the growth and decay of the follicles and the corpus luteum, as well as the change of the key reproductive hormones, enzymes and processes over time. In this work we describe recent developments of this model towards the administration of prostaglandin F2α. We validate our model by showing that the simulations agree with observations from synchronization studies and with measured progesterone data after single dose administrations of synthetic prostaglandin F2α. PMID:22980082

  20. Systems Analyses of Advanced Brayton Cycles For High Efficiency Zero Emission Plants

    SciTech Connect

    A. D. Rao; J. Francuz; A. Verma; G. S. Samuelsen

    2006-10-30

    The ultimate goal of this program is to identify the power block cycle conditions and/or configurations which could increase the overall thermal efficiency of the Baseline IGCC by about 8% on a relative basis (i.e., 8% on a heat rate basis). This document presents the cycle conditions and/or the configurations for evaluation in an initial screening analysis. These cycle conditions and/or configurations for investigation in the screening analysis are identified by literature searches and brain storming sessions. The screening analysis in turn narrows down the number of promising cases for detailed analysis.

  1. Development and proof-testing of advanced absorption refrigeration cycle concepts. Report on Phases 1 and 1A

    SciTech Connect

    Modahl, R.J.; Hayes, F.C.

    1992-03-01

    The overall objectives of this project are to evaluate, develop, and proof-test advanced absorption refrigeration cycles that are applicable to residential and commercial heat pumps for space conditioning. The heat pump system is to be direct-fired with natural gas and is to use absorption working fluids whose properties are known. Target coefficients of performance (COPs) are 1.6 at 47{degrees}F and 1.2 at 17{degrees} in the heating mode, and 0.7 at 95{degree}F in the cooling mode, including the effect of flue losses. The project is divided into three phases. Phase I entailed the analytical evaluation of advanced cycles and included the selection of preferred concepts for further development. Phase II involves the development and testing of critical components and of a complete laboratory breadboard version of the selected system. Phase III calls for the development of a prototype unit and is contingent on the successful completion of Phase II. This report covers Phase I work on the project. In Phase 1, 24 advanced absorption cycle/fluid combinations were evaluated, and computer models were developed to predict system performance. COP, theoretical pump power, and internal heat exchange were calculated for each system, and these calculations were used as indicators of operating and installed costs in order to rank the relative promise of each system. The highest ranking systems involve the cycle concept of absorber/generator heat exchange, generator heat exchanger/absorber heat exchange, regeneration, and resorption/desorption, in combination with the NH{sub 3}/H{sub 2}O/LiBr ternary absorption fluid mixture or with the NH{sub 3}/H{sub 2}O binary solution. Based upon these conclusions, the recommendation was made to proceed to Phase II, the laboratory breadboard proof-of- concept.

  2. Response of the benthic methane cycle to climate variability: insights from reaction-transport simulations

    NASA Astrophysics Data System (ADS)

    Regnier, P.; Dale, A.; Arndt, S.; Tsandev, I.; Ridgwell, A.

    2012-04-01

    Methanogenesis by microorganisms within anoxic sediments is a very slow process of CH4 production. Yet, over thousands or millions of years methanogenesis has resulted in vast CH4 accumulation, either dissolved in the interstitial water, in the form of gas bubbles, or condensed as gas hydrates (Buffett and Archer, 2004). On a global scale, sediments are thus the largest methane reservoir on Earth (Buffett and Archer, 2004), and they may exert a significant influence on the carbon cycle and Earth climate. For instance, CH4 release due to destabilization of gas hydrates has resulted in significant increases in atmospheric CH4 concentration during Earth's history (e.g. Dickens, 2003). Geochemical and microbiological evidence, together with mass balance calculations, nonetheless suggest that currently, up to 90% of the methane produced globally in marine sediments is consumed in situ before reaching the seafloor by the biogeochemical process of anaerobic oxidation of methane (AOM). Yet, the extent to which the efficiency of this methane sink could be affected by climate change remains essentially unknown. This contribution reviews how recent model developments, including improved representations of the physical, chemical and biological components of the benthic system, have led to novel insights into the transient response of the benthic methane cycle at the centennial timescale. Reactive-transport model simulations combined with high resolution data are used to quantify present-day rates of methanogenesis and methanotrophy in shelf sediments where free methane gas is widespread. Results reveal that in passive sediments AOM is currently a very efficient subsurface barrier against both the aqueous and gaseous methane flux migrating towards the seafloor. Numerical experiments are then carried out to forecast the evolution of the methane cycle over the next century, triggered by changes in climate. Simulations predict that the gaseous methane inventory will increase, but

  3. A new chronology and probabilistic assessment of sea-level variability over five glacial cycles

    NASA Astrophysics Data System (ADS)

    Grant, Katharine M.; Rohling, Eelco J.; Bronk Ramsey, Christopher; Cheng, Hai; Edwards, R. Lawrence; Florindo, Fabio; Heslop, David; Marra, Fabrizio; Roberts, Andrew P.; Tamisiea, Mark E.; Williams, Felicity

    2015-04-01

    On geological timescales, changes in sea level give an indication of the global glaciation state. To fully portray how Earth's glaciation state varied in the past, we need to consider the timing and amplitude of sea-level changes during both glacial and interglacial intervals. Ideally, we also need to consider such changes over several glacial-interglacial cycles, so that i) any systematic sea-level/ice-volume relationships can be discerned, and ii) more reliable estimates of sea-level change rates under different boundary conditions can be determined. While an increasing number of well-dated sea-level records exists for periods within the last glacial cycle, older time intervals are much less represented. For example, available reconstructions of sea level prior to the last interglacial tend to be discontinuous or of low resolution, contain large sea-level uncertainties, or have orbitally tuned chronologies that are biased by assumptions about climate: ice-volume phasings. To address these issues, we have developed a robust, radiometrically constrained timescale for continuous and centennial-resolution records of sea level and rates of sea-level change, over the last five glacial cycles (~500,000 years). Our method is based on synchronisation of Red Sea dust and relative sea-level (RSL) records to a speleothem δ18O record from Sanbao Cave (China). We have also used Bayesian and Monte Carlo-style methods to assess chronological and sea-level uncertainties, which has resulted in the first probabilistic records of sea level and sea-level change rates for periods before the last interglacial. This provides an opportunity for detailed comparisons with existing sea-level/ice-volume reconstructions, and for validating models of sea-level rise and ice-sheet dynamics. Finally, to illustrate an implication of our new sea-level records, we explored the relationship between natural (pre-anthropogenic forcing) sea-level rise rates and 'glaciation state', where the latter is

  4. Cell division of cycle of Bacillus subtilis: evidence of variability in period D.

    PubMed Central

    Holmes, M; Rickert, M; Pierucci, O

    1980-01-01

    In Bacillus subtilis the deoxyribonucleic acid content and the extent of cell division during inhibition of chromosome replication increased as a function of the average cell mass, independent of the growth rate. At each growth rate, mass, deoxyribonucleic acid, and residual division varied in different cultures. The variation is consistent with a large variability in the D period. At growth rates higher than 1.5 doublings per h at 37 degrees C, the change in D accounts for the growth rate dependence of the mass and deoxyribonucleic acid content. PMID:6768710

  5. Stratospheric and solar cycle effects on long-term variability of mesospheric ice clouds

    NASA Astrophysics Data System (ADS)

    Lübken, F.-J.; Berger, U.; Baumgarten, G.

    2009-01-01

    Model results of mesospheric ice layers and background conditions at 69°N from 1961 to 2008 are analyzed. The model nudges to European Centre for Medium-Range Weather Forecasts data below ˜45 km. Greenhouse gas concentrations in the mesosphere are kept constant. At polar mesospheric cloud (PMC) altitudes (83 km) temperatures decrease until the mid 1990s by -0.08 K/yr resulting in trends of PMC brightness, occurrence rates, and, to a lesser extent, in PMC altitudes (-0.0166 km/yr). Ice layer trends are consistent with observations by ground-based and satellite instruments. Water vapor increases at PMC heights and decreases above due to increased freeze-drying caused by the temperature trend. Temperature trends in the mesosphere mainly come from shrinking of the stratosphere and from dynamical effects. A solar cycle modulation of H2O is observed in the model consistent with satellite observations. The effect on ice layers is reduced because of redistribution of H2O by freeze-drying. The accidental coincidence of low temperatures and solar cycle minimum in the mid 1990s leads to an overestimation of solar effects on ice layers. A strong correlation between temperatures and PMC altitudes is observed. Applied to historical measurements this gives negligible temperature trends at PMC altitudes (˜0.01-0.02 K/yr). Strong correlations between PMC parameters and background conditions deduced from the model confirm the standard scenario of PMC formation. The PMC sensitivity on temperatures, water vapor, and Ly-α is investigated. PMC heights show little variation with background parameters whereas brightness and occurrence rates show large variations. None of the background parameters can be ignored regarding its influence on ice layers.

  6. Stratospheric and solar cycle effects on long-term variability of mesospheric ice clouds

    NASA Astrophysics Data System (ADS)

    Lübken, F.-J.; Berger, U.; Baumgarten, G.

    2009-11-01

    Model results of mesospheric ice layers and background conditions at 69°N from 1961 to 2008 are analyzed. The model nudges to European Centre for Medium-Range Weather Forecasts data below ˜45 km. Greenhouse gas concentrations in the mesosphere are kept constant. At polar mesospheric cloud (PMC) altitudes (83 km) temperatures decrease until the mid 1990s by -0.08 K/yr resulting in trends of PMC brightness, occurrence rates, and, to a lesser extent, in PMC altitudes (-0.0166 km/yr). Ice layer trends are consistent with observations by ground-based and satellite instruments. Water vapor increases at PMC heights and decreases above due to increased freeze-drying caused by the temperature trend. Temperature trends in the mesosphere mainly come from shrinking of the stratosphere and from dynamical effects. A solar cycle modulation of H2O is observed in the model consistent with satellite observations. The effect on ice layers is reduced because of redistribution of H2O by freeze-drying. The accidental coincidence of low temperatures and solar cycle minimum in the mid 1990s leads to an overestimation of solar effects on ice layers. A strong correlation between temperatures and PMC altitudes is observed. Applied to historical measurements this gives negligible temperature trends at PMC altitudes (˜0.01-0.02 K/yr). Strong correlations between PMC parameters and background conditions deduced from the model confirm the standard scenario of PMC formation. The PMC sensitivity on temperatures, water vapor, and Ly-α is investigated. PMC heights show little variation with background parameters whereas brightness and occurrence rates show large variations. None of the background parameters can be ignored regarding its influence on ice layers.

  7. Advanced technology cogeneration system conceptual design study: Closed cycle gas turbines

    NASA Technical Reports Server (NTRS)

    Mock, E. A. T.; Daudet, H. C.

    1983-01-01

    The results of a three task study performed for the Department of Energy under the direction of the NASA Lewis Research Center are documented. The thermal and electrical energy requirements of three specific industrial plants were surveyed and cost records for the energies consumed were compiled. Preliminary coal fired atmospheric fluidized bed heated closed cycle gas turbine and steam turbine cogeneration system designs were developed for each industrial plant. Preliminary cost and return-on-equity values were calculated and the results compared. The best of the three sites was selected for more detailed design and evaluation of both closed cycle gas turbine and steam turbine cogeneration systems during Task II. Task III involved characterizing the industrial sector electrical and thermal loads for the 48 contiguous states, applying a family of closed cycle gas turbine and steam turbine cogeneration systems to these loads, and conducting a market penetration analysis of the closed cycle gas turbine cogeneration system.

  8. Orbit Transfer Vehicle (OTV) advanced expander cycle engine point design study. Volume 3: Engine data summary

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The engine operating characteristics were examined. Inlet pressure effects, tank pressurization effects, steady-state specific impulse, and the steady-state cycle were studied. The propellant flow schematic and operating sequence are presented. Engine hardware drawings are included.

  9. The role of microstructural variability on the very high cycle fatigue lifetime variability of the alpha + beta titanium alloy, Ti-6246

    NASA Astrophysics Data System (ADS)

    Szczepanski, Christopher J.

    2008-12-01

    The fatigue behavior of structural components in the regime of very high cycle fatigue (VHCF) (106-109 cycles) has been attracting increased commercial interest as components are increasingly being called upon to perform in this regime of lifetimes. In VHCF, the applied stresses relative to the yield stress are very low. Therefore, it is presumed that a substantial portion of fatigue lifetime is consumed by the fatigue crack initiation process, and that cyclic plasticity only accumulates in microstructural neighborhoods that are susceptible to fatigue damage accumulation. Thus, microstructural heterogeneity is believed to significantly effect the fatigue lifetime variability. The very high cycle fatigue behavior of Ti-6246 has been investigated using ultrasonic fatigue techniques, and lifetimes ranging from 10 6-109 cycles have been observed. Fatigue cracks initiate by facet formation within alphap grains. It has been found that the facets form in grains that are slightly larger than average and that the facets appear to form by a process of slip since the facet plane normals are oriented approximately 35-55° with respect to the tensile axis. Three characteristic fatigue crack initiation sites have been identified. These initiation sites, ranked in order of increasing fatigue resistance are: surface, subsurface with isolated facets, and subsurface with contiguous transgranular faceting. The texture of the material in these initiation regions is favorable for basal and prism slip. This texture is derived from the prior beta texture, and a mechanism of fatigue crack initiation resulting from strain incompatibility has been proposed. Fatigue crack growth experiments have been completed to measure the influence of local texture on the ease of fatigue crack initiation and the resulting fatigue crack growth rates. These experiments have found that the controlling microstructural dimension is on the order of 20-25 mum. The texture appears to affect initiation of fatigue

  10. Menstrual cycles continue into advanced old age in the common chimpanzee (Pan troglodytes).

    PubMed

    Lacreuse, Agnès; Chennareddi, Lakshmi; Gould, Kenneth G; Hawkes, Kristen; Wijayawardana, Sameera R; Chen, Jian; Easley, Kirk A; Herndon, James G

    2008-09-01

    A long postreproductive lifespan may distinguish women from all other female primates. A long-held consensus among reproductive scientists has been that our closest living relative, the chimpanzee (Pan troglodytes), experiences menstrual cycles until death. However, a recent study of biannual assessments of gonadotropins, but lacking observations of menstruation, concluded that menopause occurs in chimpanzees between 35 and 40 yr of age. A separate report, but on wild chimpanzees, documented fertility through the 40-44 age range in all populations studied. These contradictory reports pose questions about differences between wild and captive populations and about assessments of menopause. The present study revisits this controversy by analyzing longitudinal records of anogenital swelling and menstruation in 89 female chimpanzees aged 6 to 59 yr (n = 2386 records on cycle length), monitored for most of their adult lives at the Yerkes National Primate Research Center. Twenty of these chimpanzees were observed past 39 yr of age; all 20 displayed menstrual cycles beyond this age, as confirmed by at least two observations of menses about 35 days apart. Three of these were older than 50 yr and still displayed menstrual cycles. Only the oldest female appeared menopausal, with cycles of anogenital swelling ceasing 2 yr prior to her death at age 59. Random-effects statistical modeling reveals a slight decrease in cycle length until 20 yr of age and a slight lengthening thereafter. Mean cycle length across the lifespan is 35.4 days. Our findings, based upon actual observations of menstrual cycles, suggest that menopause in the chimpanzee is rare, occurring near the end of the lifespan. PMID:18495682

  11. A Novel Variable Field System for Field-Cycled Dynamic Nuclear Polarization Spectroscopy

    PubMed Central

    Shet, Keerthi; Caia, George L.; Kesselring, Eric; Samouilov, Alexandre; Petryakov, Sergey; Lurie, David J.; Zweier, Jay L.

    2014-01-01

    Dynamic nuclear polarization (DNP) is an NMR-based technique which enables detection and spectral characterization of endogenous and exogenous paramagnetic substances measured via transfer of polarization from the saturated unpaired electron spin system to the NMR active nuclei. A variable field system capable of performing DNP spectroscopy with NMR detection at any magnetic field in the range 0 - 0.38 T is described. The system is built around a clinical open-MRI system. To obtain EPR spectra via DNP, partial cancellation of the detection field B0NMR is required to alter the evolution field B0EPR at which the EPR excitation is achieved. The addition of resistive actively shielded field cancellation coils in the gap of the primary magnet provides this field offset in the range of 0–100 mT. A description of the primary magnet, cancellation coils, power supplies, interfacing hardware, RF electronics and console are included. Performance of the instrument has been evaluated by acquiring DNP spectra of phantoms with aqueous nitroxide solutions (TEMPOL) at three NMR detection fields of 97 G, 200 G and 587 G corresponding to 413 kHz, 851.6 kHz and 2.5 MHz respectively and fixed EPR evolution field of 100 G corresponding to an irradiation frequency of 282.3 MHz. This variable field DNP system offers great flexibility for the performance of DNP spectroscopy with independent optimum choice of EPR excitation and NMR detection fields. PMID:20570197

  12. Assessing Global Water Storage Variability from GRACE: Trends, Seasonal Cycle, Subseasonal Anomalies and Extremes

    NASA Astrophysics Data System (ADS)

    Humphrey, Vincent; Gudmundsson, Lukas; Seneviratne, Sonia I.

    2016-03-01

    Throughout the past decade, the Gravity Recovery and Climate Experiment (GRACE) has given an unprecedented view on global variations in terrestrial water storage. While an increasing number of case studies have provided a rich overview on regional analyses, a global assessment on the dominant features of GRACE variability is still lacking. To address this, we survey key features of temporal variability in the GRACE record by decomposing gridded time series of monthly equivalent water height into linear trends, inter-annual, seasonal, and subseasonal (intra-annual) components. We provide an overview of the relative importance and spatial distribution of these components globally. A correlation analysis with precipitation and temperature reveals that both the inter-annual and subseasonal anomalies are tightly related to fluctuations in the atmospheric forcing. As a novelty, we show that for large regions of the world high-frequency anomalies in the monthly GRACE signal, which have been partly interpreted as noise, can be statistically reconstructed from daily precipitation once an adequate averaging filter is applied. This filter integrates the temporally decaying contribution of precipitation to the storage changes in any given month, including earlier precipitation. Finally, we also survey extreme dry anomalies in the GRACE record and relate them to documented drought events. This global assessment sets regional studies in a broader context and reveals phenomena that had not been documented so far.

  13. Development of advanced off-design models for supercritical carbon dioxide power cycles

    SciTech Connect

    Dyreby, J. J.; Klein, S. A.; Nellis, G. F.; Reindl, D. T.

    2012-07-01

    In the search for increased efficiency of utility-scale electricity generation, Brayton cycles operating with supercritical carbon dioxide (S-CO{sub 2}) have found considerable interest. There are two main advantages of a S-CO{sub 2} Brayton cycle compared to a Rankine cycle: 1) equal or greater thermal efficiencies can be realized using significantly smaller turbomachinery, and 2) heat rejection is not limited by the saturation temperature of the working fluid, which has the potential to reduce or completely eliminate the need for cooling water and instead allow dry cooling. While dry cooling is especially advantageous for power generation in arid climates, a reduction of water consumption in any location will be increasingly beneficial as tighter environmental regulations are enacted in the future. Because daily and seasonal weather variations may result in a plant operating away from its design point, models that are capable of predicting the off-design performance of S-CO{sub 2} power cycles are necessary for characterizing and evaluating cycle configurations and turbomachinery designs on an annual basis. To this end, an off-design model of a recuperated Brayton cycle was developed based on the radial turbomachinery currently being investigated by Sandia National Laboratory. (authors)

  14. Recurrence pattern in patients with locally advanced renal cell carcinoma: The implications of clinicopathological variables

    PubMed Central

    Sameh, Wael M.; Hashad, Mohammed M.; Eid, Ahmed A.; Abou Yousif, Tamer A.; Atta, Mohammed A.

    2012-01-01

    Objectives Recurrence rates for patients with locally advanced renal cell carcinoma (LARCC) remain high. To date the predictors of recurrence in those patients remain controversial. The aim of the present study was to assess the relapse pattern in those patients and identify predictors for recurrence. Patients and methods We evaluated retrospectively 112 consecutive patients who underwent surgery for LARCC (T3–T4N0M0) between January 2000 and December 2010. Clinical and pathological data were collected from hospital medical records and compiled into a computerized database. Studied variables were age, mode of presentation, Tumour-Node-Metastasis (TNM) stage, Fuhrman nuclear grade, histological subtype, tumour size, venous thrombus level, collecting-system invasion and sarcomatoid differentiation. Recurrence-free survival (RFS) was estimated using the Kaplan–Meier method. Univariate and multivariate analyses were conducted. Results Patients were followed for a mean and median follow-up of 33 and 24 months, respectively, after surgery. During the follow-up, recurrences (distant and/or local) were recorded in 58 patients, representing 52% of the cohort. The mean and median times to recurrence were 25 and 13 months, respectively. Sites of recurrence were multiple in 36 patients (62%), lung only in 14 (24%), and local in eight (14%). RFS rates at 1, 2, and 5 years were 50%, 43% and 34%, respectively, while the median RFS was 23.7 months. Using univariate analysis, RFS after nephrectomy was significantly shorter in patients aged <70 years, symptomatic at presentation, with larger tumours, higher nuclear grade, collecting-system invasion, and/or sarcomatoid differentiation. After multivariate analysis, T-stage, nuclear grade and sarcomatoid differentiation retained their power as independent predictors of RFS (P = 0.032, <0.001 and 0.003, respectively). Conclusions For patients with LARCC, T-stage, grade and sarcomatoid differentiation independently dictate the

  15. Generic Repository Concepts and Thermal Analysis for Advanced Fuel Cycles - 12477

    SciTech Connect

    Hardin, Ernest; Blink, James; Carter, Joe; Fratoni, Massimiliano; Greenberg, Harris; Sutton, Mark; Howard, Robert

    2012-07-01

    A geologic disposal concept for spent nuclear fuel (SNF) or high-level waste (HLW) consists of three components: waste inventory, geologic setting, and concept of operations. A set of reference geologic disposal concepts has been developed by the U.S. Department of Energy (DOE), Used Fuel Disposition campaign. Reference concepts are identified for crystalline rock, clay/shale, bedded salt, and deep borehole (crystalline basement) geologic settings. These were analyzed for waste inventory cases representing a range of waste types that could be produced by advanced nuclear fuel cycles. Concepts of operation consisting of emplacement mode, repository layout, and engineered barrier descriptions, were selected based on international progress. All of these disposal concepts are enclosed emplacement modes, whereby waste packages are in direct contact with encapsulating engineered or natural materials. Enclosed modes have less capacity to dissipate heat than open modes such as that proposed for a repository at Yucca Mountain. Thermal analysis has identified important relationships between waste package size and capacity, and the duration of surface decay storage needed to meet temperature limits for different disposal concepts. For the crystalline rock and clay/shale repository concepts, a waste package surface temperature limit of 100 deg. C was assumed to prevent changes in clay-based buffer material or clay-rich host rock. Surface decay storage of 50 to 100 years is needed for disposal of high-burnup LWR SNF in 4-PWR packages, or disposal of HLW glass from reprocessing LWR uranium oxide (UOX) fuel. High-level waste (HLW) from reprocessing of metal fuel used in a fast reactor could be disposed after decay storage of 50 years or less. For disposal in salt the rock thermal conductivity is significantly greater, and higher temperatures (200 deg. C) can be tolerated at the waste package surface. Decay storage of 10 years or less is needed for high-burnup LWR SNF in 4-PWR

  16. CONCEPTUAL DESIGN AND ECONOMICS OF THE ADVANCED CO2 HYBRID POWER CYCLE

    SciTech Connect

    A. Nehrozoglu

    2004-12-01

    Research has been conducted under United States Department of Energy Contract DEFC26-02NT41621 to analyze the feasibility of a new type of coal-fired plant for electric power generation. This new type of plant, called the Advanced CO{sub 2} Hybrid Power Plant, offers the promise of efficiencies nearing 36 percent, while concentrating CO{sub 2} for 100% sequestration. Other pollutants, such as SO{sub 2} and NOx, are sequestered along with the CO{sub 2} yielding a zero emissions coal plant. The CO{sub 2} Hybrid is a gas turbine-steam turbine combined cycle plant that uses CO{sub 2} as its working fluid to facilitate carbon sequestration. The key components of the plant are a cryogenic air separation unit (ASU), a pressurized circulating fluidized bed gasifier, a CO{sub 2} powered gas turbine, a circulating fluidized bed boiler, and a super-critical pressure steam turbine. The gasifier generates a syngas that fuels the gas turbine and a char residue that, together with coal, fuels a CFB boiler to power the supercritical pressure steam turbine. Both the gasifier and the CFB boiler use a mix of ASU oxygen and recycled boiler flue gas as their oxidant. The resulting CFB boiler flue gas is essentially a mixture of oxygen, carbon dioxide and water. Cooling the CFB flue gas to 80 deg. F condenses most of the moisture and leaves a CO{sub 2} rich stream containing 3%v oxygen. Approximately 30% of this flue gas stream is further cooled, dried, and compressed for pipeline transport to the sequestration site (the small amount of oxygen in this stream is released and recycled to the system when the CO{sub 2} is condensed after final compression and cooling). The remaining 70% of the flue gas stream is mixed with oxygen from the ASU and is ducted to the gas turbine compressor inlet. As a result, the gas turbine compresses a mixture of carbon dioxide (ca. 64%v) and oxygen (ca. 32.5%v) rather than air. This carbon dioxide rich mixture then becomes the gas turbine working fluid and

  17. THE MISSION AND ACCOMPLISHMENTS FROM DOE’S FUEL CYCLE RESEARCH AND DEVELOPMENT (FCRD) ADVANCED FUELS CAMPAIGN

    SciTech Connect

    J. Carmack; L. Braase; F. Goldner

    2015-09-01

    The mission of the Advanced Fuels Campaign (AFC) is to perform Research, Development, and Demonstration (RD&D) activities for advanced fuel forms (including cladding) to enhance the performance and safety of the nation’s current and future reactors, enhance proliferation resistance of nuclear fuel, effectively utilize nuclear energy resources, and address the longer-term waste management challenges. This includes development of a state of the art Research and Development (R&D) infrastructure to support the use of a “goal oriented science based approach.” AFC uses a “goal oriented, science based approach” aimed at a fundamental understanding of fuel and cladding fabrication methods and performance under irradiation, enabling the pursuit of multiple fuel forms for future fuel cycle options. This approach includes fundamental experiments, theory, and advanced modeling and simulation. One of the most challenging aspects of AFC is the management, integration, and coordination of major R&D activities across multiple organizations. AFC interfaces and collaborates with Fuel Cycle Technologies (FCT) campaigns, universities, industry, various DOE programs and laboratories, federal agencies (e.g., Nuclear Regulatory Commission [NRC]), and international organizations. Key challenges are the development of fuel technologies to enable major increases in fuel performance (safety, reliability, power and burnup) beyond current technologies, and development of characterization methods and predictive fuel performance models to enable more efficient development and licensing of advanced fuels. Challenged with the research and development of fuels for two different reactor technology platforms, AFC targeted transmutation fuel development and focused ceramic fuel development for Advanced LWR Fuels.

  18. Interannual Variability of the Tropical Water Cycle: Capabilities in the TRMM Era and Challenges for GPM

    NASA Technical Reports Server (NTRS)

    Robertson, Franklin R.

    2003-01-01

    Considerable uncertainty surrounds the issue of whether precipitation over the tropical oceans (30" NE) systematically changes with interannual sea-surface temperature (SST) anomalies that accompany El Nino (warm) and La Nina (cold) events. Although it is well documented that El Nino-Southern Oscillation (ENSO) events with marked SST changes over the tropical oceans, produce significant regional changes in precipitation, water vapor, and radiative fluxes in the tropics, we still cannot yet adequately quantify the associated net integrated changes to water and heat balance over the entire tropical oceanic or land sectors. Robertson et al., [2001 GRL] for example, showed that substantial disagreement exists among contemporary satellite estimates of interannual variations in tropical rainfall that are associated with SST changes. Berg et al., [2002 J. Climate] have documented the distinct differences between precipitation structure over the eastern and western Pacific ITCZ and noted how various satellite precipitation algorithms may respond quite differently to ENSO modulations of these precipitation regimes. Resolving this uncertainty is important since precipitation and latent heat release variations over land and ocean sectors are key components of the tropical heat balance in its most aggregated form. Rainfall estimates from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) averaged over the tropical oceans have not solved this issue and, in fact, show marked differences with estimates from two TRMM Microwave Imager (TMI) passive microwave algorithms. In this paper we will focus on findings that uncertainties in microphysical assumptions necessitated by the single-frequency PR measurement pose difficulties for detecting climate-related precipitation signals. Recent work has shown that path-integrated attenuation derived from the effects of precipitation on the radar return from the ocean surface exhibits interannual variability that agrees

  19. Short time variability of solar corona during recent solar cycle minimum

    NASA Astrophysics Data System (ADS)

    Siarkowski, Marek; Gryciuk, Magdalena; Gburek, Szymon; Sylwester, Janusz; Sylwester, Barbara; Kepa, Anna; Buczkowska, Agnieszka; Kowalinski, Miroslaw

    Sphinx is the X-ray spectrophotometer designed to measure X-ray emission from the Sun in the energy range between 0.8 keV and 15 keV. The instrument is placed onboard Russian KORONAS-PHOTON satellite launched on January 30, 2009. In this paper we present the observations of coronal emission obtained between March-April and August-September 2009, i.e. the times towards the end of the last, very prolonged and deep minimum of solar activity. Prompt analysis of SphinX spectra reveal the variability of the average coronal plasma charac-teristics like the temperature and emission measure. These data are used to compare SphinX and GOES measurements, for selected times. Examples of many sub/microflare events with maxima of the X-ray flux, observed much below the GOES sensitivity threshold level will be presented.

  20. Environmental Variability and Fluctuation of Coccidioidomycosis (Valley Fever) In California: Based on a New Framework Involving Fungal Life Cycle

    NASA Astrophysics Data System (ADS)

    Jia, S.; Okin, G. S.; Shafir, S. C.

    2013-12-01

    Coccidioidomycosis (valley fever), caused by inhalation of spores from pathogenic fungus includingCoccidiodes immitis (C. immitis) and Coccidioides posadasii (C. posadasii), is a disease endemic to arid regions in the southwest US, as well as parts of Central and South America. With a projected increase of drought in this region, an improved understanding of environmental factors behind the outbreaks of coccidioidomycosis will enable the prediction of coccidioidomycosis in a changing climate regime. Previous research shows the infections correlate with climate conditions including precipitation, temperature, and dust. However, most studies focus only on the environmental conditions of fungus growth, which is the first stage in the fungal life cycle. In contrast, we extend the analysis to the following two stages in the life cycle, arthrospore formation and dispersal, to form a better model to predict the disease outbreaks. Besides climate conditions, we use relative spectral mixture analysis (RSMA) based on MODIS MOD43 nadir BRDF adjusted reflectance (NBAR) data to derive the relative dynamics of green vegetation, non-photosynthetic vegetation and bare soil coverage as better indicators of soil moisture, which is important for arthospore formation and dispersal. After detecting the hotspots of disease outbreaks, we correlate seasonal incidence from 2000 to 2010 with the environmental variables zero to eight seasons before to obtain candidates for stepwise regression. Regression result shows a seasonal difference in the leading explanatory variables. Such difference indicates the different seasonal main influential process from fungal life cycle. C. immitis (fungus responsible for coccidioidomycosis outbreaks in California) growth explains outbreaks in winter and fall better than other two stages in the life cycle, while arthospore formation is more responsible for spring and summer outbreaks. As the driest season, summer has the largest area related with arthospore

  1. The nature of millennial-scale climate variability during the last two glacial cycles

    NASA Astrophysics Data System (ADS)

    Skinner, Luke; Margari, Vasiliki; Tzedakis, Chronis; Ganopolski, Andrey; Vautravers, Maryline; Shackleton, Nicholas

    2010-05-01

    During the last glacial period, iceberg discharges into the North Atlantic led to a disruption of the Atlantic Meridional Overturning Circulation (AMOC), a cooling of the Northern Hemisphere, and a warming of Antarctica. This asymmetric response has been explained in terms of a bipolar seesaw mechanism, whereby changes in the strength of the AMOC result in changes in interhemispheric heat transport. However, it remains unclear to what extent the response of the AMOC and the operation of the bipolar seesaw may depend on background climate conditions, or the magnitude/delivery of freshwater flux to the North Atlantic. Here we present foraminiferal isotope and pollen records from the Portuguese margin from the last and penultimate glacial periods. A comparison of our records with temperature reconstructions from Antarctica indicates that the bipolar seesaw was a characteristic feature of both glacial periods. However, our comparison also underlines the dependence of the bipolar seesaw on background climate as well as the magnitude of iceberg discharge. Our results suggest that an intensified hydrological cycle may lead to a weaker overturning circulation with a smaller disruption threshold and extended North Atlantic stadial durations.

  2. Nitrate variability in coastal North Carolina rainwater and its impact on the nitrogen cycle in rain

    SciTech Connect

    Kieber, R.J.; Rhines, M.F.; Willey, J.D.; Avery, G.B. Jr.

    1999-02-01

    The concentration range for nitrite (NO{sub 2}{sup {minus}}) in 115 rain samples collected in Wilmington, NC, from June 1996 through February 1998 was 0.022--0.603 {micro}M. Nitrite concentrations did not correlate with precipitation volume, suggesting a continuous supply of nitrite during rain events possibly by slow scavenging of gas-phase material such as HONO(g) or NO{sub 2}(g) or in-cloud oxidation of other reduced forms of nitrogen. Nitrite levels exhibited no seasonal oscillations, which is in contrast to other rainwater parameters at this site such as pH, nitrate, non-seasalt sulfate (NSS) and ammonium. Concentrations of nitrite did not correlate with concentrations of pollutant indicators (pH, nitrate, and NSS). The concentration of nitrite in both winter El Nino rains and summer tropical rains was less than half its concentration in non-El Nino or non-tropical events, suggesting a possible terrestrial source of nitrite or nitrite precursor. Controlled laboratory studies demonstrated that hydrogen peroxide can oxidize nitrite in rainwater at environmentally relevant H{sup +}, H{sub 2}O{sub 2}, and NO{sub 2}{sup {minus}} concentrations. Nitrite oxidation by H{sub 2}O{sub 2} in the aqueous phase has important ramifications with respect to N cycling and acid generation within the troposphere.

  3. Variability of prediction of maximal oxygen concumption on the cycle ergometer using standard equations

    NASA Technical Reports Server (NTRS)

    Greenisen, Michael C.; Fortney, Suzanne M.; Lee, Stuart M. C.; Moore, Alan D.; Barrows, Linda H.

    1993-01-01

    Several investigations within the Exercise Countermeasures Project at the NASA Johnson Space Center focused on the assessment of maximum oxygen consumption (VO2(sub max)) within the Astronaut Corps pre- and postspace flight. Investigations during the Apollo era suggested that there was a significant decrease in postflight VO2(sub max) when compared to preflight values, and current studies have documented that this trend continues in the Space Shuttle era. It is generally accepted and was confirmed in our laboratory that VO2(sub max) can be predicted from submaximal measures taken during graded exercise tests on the cycle ergometer with respect to populations. However, previous work had not examined the effect of day-to-day variations in the physiologic responses that might alter these predictions for individuals. Stability of individual submaximal data over serial tests is important so that predicted changes in VO2(sub max) are reflective of actual VO2(sub max) changes. Therefore, the purpose of this investigation was to determine which of the accepted equations to predict VO2(sub max) would be less affected by normal daily physiologic changes.

  4. How to quantify uncertainty and variability in life cycle assessment: the case of greenhouse gas emissions of gas power generation in the US

    NASA Astrophysics Data System (ADS)

    Hauck, M.; Steinmann, Z. J. N.; Laurenzi, I. J.; Karuppiah, R.; Huijbregts, M. A. J.

    2014-07-01

    This study quantified the contributions of uncertainty and variability to the range of life-cycle greenhouse gas (LCGHG) emissions associated with conventional gas-fired electricity generation in the US. Whereas uncertainty is defined as lack of knowledge and can potentially be reduced by additional research, variability is an inherent characteristic of supply chains and cannot be reduced without physically modifying the system. The life-cycle included four stages: production, processing, transmission and power generation, and utilized a functional unit of 1 kWh of electricity generated at plant. Technological variability requires analyses of life cycles of individual power plants, e.g. combined cycle plants or boilers. Parameter uncertainty was modeled via Monte Carlo simulation. Our approach reveals that technological differences are the predominant cause for the range of LCGHG emissions associated with gas power, primarily due to variability in plant efficiencies. Uncertainties in model parameters played a minor role for 100 year time horizon. Variability in LCGHG emissions was a factor of 1.4 for combined cycle plants, and a factor of 1.3 for simple cycle plants (95% CI, 100 year horizon). The results can be used to assist decision-makers in assessing factors that contribute to LCGHG emissions despite uncertainties in parameters employed to estimate those emissions.

  5. Impact of climate variability on N and C flux within the life cycle of biofuels produced from crop residues

    NASA Astrophysics Data System (ADS)

    Pourhashem, G.; Block, P. J.; Adler, P. R.; Spatari, S.

    2013-12-01

    Biofuels from agricultural feedstocks (lignocellulose) are under development to meet national policy objectives for producing domestic renewable fuels. Using crop residues such as corn stover as feedstock for biofuel production can minimize the risks associated with food market disruption; however, it demands managing residue removal to minimize soil carbon loss, erosion, and to ensure nutrient replacement. Emissions of nitrous oxide and changes to soil organic carbon (SOC) are subject to variability in time due to local climate conditions and cultivation practices. Our objective is to investigate the effect of climate inputs (precipitation and temperature) on biogeochemical greenhouse gas (GHG) emissions (N2O and SOC expressed as CO2) within the life cycle of biofuels produced from agricultural residues. Specifically, we investigate the impact of local climate variability on soil carbon and nitrogen fluxes over a 20-year biorefinery lifetime where biomass residue is used for lignocellulosic ethanol production. We investigate two cases studied previously (Pourhashem et al, 2013) where the fermentable sugars in the agricultural residue are converted to ethanol (biofuel) and the lignin byproduct is used in one of two ways: 1) power co-generation; or 2) application to land as a carbon/nutrient-rich amendment to soil. In the second case SOC losses are mitigated through returning the lignin component to land while the need for fertilizer addition is also eliminated, however in both cases N2O and SOC are subject to variability due to variable climate conditions. We used the biogeochemical model DayCent to predict soil carbon and nitrogen fluxes considering soil characteristics, tillage practices and local climate (e.g. temperature and rainfall). We address the impact of climate variability on the soil carbon and nitrogen fluxes by implementing a statistical bootstrap resampling method based on a historic data set (1980 to 2000). The ensuing probabilistic outputs from the

  6. Topographic variability and the influence of soil erosion on the carbon cycle

    NASA Astrophysics Data System (ADS)

    Dialynas, Yannis G.; Bastola, Satish; Bras, Rafael L.; Billings, Sharon A.; Markewitz, Daniel; Richter, Daniel deB.

    2016-05-01

    Soil erosion, particularly that caused by agriculture, is closely linked to the global carbon (C) cycle. There is a wide range of contrasting global estimates of how erosion alters soil-atmosphere C exchange. This can be partly attributed to limited understanding of how geomorphology, topography, and management practices affect erosion and oxidation of soil organic C (SOC). This work presents a physically based approach that stresses the heterogeneity at fine spatial scales of SOC erosion, SOC burial, and associated soil-atmosphere C fluxes. The Holcombe's Branch watershed, part of the Calhoun Critical Zone Observatory in South Carolina, USA, is the case study used. The site has experienced some of the most serious agricultural soil erosion in North America. We use SOC content measurements from contrasting soil profiles and estimates of SOC oxidation rates at multiple soil depths. The methodology was implemented in the tRIBS-ECO (Triangulated Irregular Network-based Real-time Integrated Basin Simulator-Erosion and Carbon Oxidation), a spatially and depth-explicit model of SOC dynamics built within an existing coupled physically based hydro-geomorphic model. According to observations from multiple soil profiles, about 32% of the original SOC content has been eroded in the study area. The results indicate that C erosion and its replacement exhibit significant topographic variation at relatively small scales (tens of meters). The episodic representation of SOC erosion reproduces the history of SOC erosion better than models that use an assumption of constant erosion in space and time. The net atmospheric C exchange at the study site is estimated to range from a maximum source of 14.5 g m-2 yr-1 to a maximum sink of -18.2 g m-2 yr-1. The small-scale complexity of C erosion and burial driven by topography exerts a strong control on the landscape's capacity to serve as a C source or a sink.

  7. Gait variability and basal ganglia disorders: stride-to-stride variations of gait cycle timing in Parkinson's disease and Huntington's disease

    NASA Technical Reports Server (NTRS)

    Hausdorff, J. M.; Cudkowicz, M. E.; Firtion, R.; Wei, J. Y.; Goldberger, A. L.

    1998-01-01

    The basal ganglia are thought to play an important role in regulating motor programs involved in gait and in the fluidity and sequencing of movement. We postulated that the ability to maintain a steady gait, with low stride-to-stride variability of gait cycle timing and its subphases, would be diminished with both Parkinson's disease (PD) and Huntington's disease (HD). To test this hypothesis, we obtained quantitative measures of stride-to-stride variability of gait cycle timing in subjects with PD (n = 15), HD (n = 20), and disease-free controls (n = 16). All measures of gait variability were significantly increased in PD and HD. In subjects with PD and HD, gait variability measures were two and three times that observed in control subjects, respectively. The degree of gait variability correlated with disease severity. In contrast, gait speed was significantly lower in PD, but not in HD, and average gait cycle duration and the time spent in many subphases of the gait cycle were similar in control subjects, HD subjects, and PD subjects. These findings are consistent with a differential control of gait variability, speed, and average gait cycle timing that may have implications for understanding the role of the basal ganglia in locomotor control and for quantitatively assessing gait in clinical settings.

  8. Advances in Global Water Cycle Science Made Possible by Global Precipitation Mission (GPM)

    NASA Technical Reports Server (NTRS)

    Smith, Eric A.; Starr, David OC. (Technical Monitor)

    2001-01-01

    Within this decade the internationally sponsored Global Precipitation Mission (GPM) will take an important step in creating a global precipitation observing system from space. One perspective for understanding the nature of GPM is that it will be a hierarchical system of datastreams from very high caliber combined dual frequency radar/passive microwave (PMW) rain-radiometer retrievals, to high caliber PMW rain-radiometer only retrievals, and on to blends of the former datastreams with other less-high caliber PMW-based and IR-based rain retrievals. Within the context of NASA's role in global water cycle science and its own Global Water & Energy Cycle (GWEC) program, GPM is the centerpiece mission for improving our understanding of the global water cycle from a space-based measurement perspective. One of the salient problems within our current understanding of the global water and energy cycle is determining whether a change in the rate of the water cycle is accompanying changes in global temperature. As there are a number of ways in which to define a rate-change of the global water cycle, it is not entirely clear as to what constitutes such a determination, This paper presents an overview of the Global Precipitation Mission and how its datasets can be used in a set of quantitative tests within the framework of the oceanic and continental water budget equations to determine comprehensively whether substantive rate changes do accompany perturbations in global temperatures and how such rate changes manifest themselves in both water storage and water flux transport processes.

  9. Advanced glycation end products are mitogenic signals and trigger cell cycle reentry of neurons in Alzheimer's disease brain.

    PubMed

    Kuhla, Angela; Ludwig, Sophie C; Kuhla, Björn; Münch, Gerald; Vollmar, Brigitte

    2015-02-01

    Neurons that reenter the cell cycle die rather than divide, a phenomenon that is associated with neurodegeneration in Alzheimer's disease (AD). Reexpression of cell-cycle related genes in differentiated neurons in AD might be rooted in aberrant mitogenic signaling. Because microglia and astroglia proliferate in the vicinity of amyloid plaques, it is likely that plaque components or factors secreted from plaque-activated glia induce neuronal mitogenic signaling. Advanced glycation end products (AGEs), protein-bound oxidation products of sugar, might be one of those mitogenic compounds. Cyclin D1 positive neurons are colocalized with AGEs or directly surrounded by extracellular AGE deposits in AD brain. However, a direct proof of DNA replication in these cells has been missing. Here, we report by using fluorescent in situ hybridization that consistent with the expression of cell cycle proteins, hyperploid neuronal cells are in colocalization with AGE staining in AD brains but not in nondemented controls. To complement human data, we used apolipoprotein E-deficient mice as model of neurodegeneration and showed that increased oxidative stress caused an intensified neuronal deposition of AGEs, being accompanied by an activation of the MAPK cascade via RAGE. This cascade, in turn, induced the expression of cyclin D1 and DNA replication. In addition, reduction of oxidative stress by application of α-lipoic acid decreased AGE accumulations, and this decrease was accompanied by a reduction in cell cycle reentry and a more euploid neuronal genome. PMID:25448604

  10. Metabolic engineering in the biotechnological production of organic acids in the tricarboxylic acid cycle of microorganisms: Advances and prospects.

    PubMed

    Yin, Xian; Li, Jianghua; Shin, Hyun-Dong; Du, Guocheng; Liu, Long; Chen, Jian

    2015-11-01

    Organic acids, which are chemically synthesized, are also natural intermediates in the metabolic pathways of microorganisms, among which the tricarboxylic acid (TCA) cycle is the most crucial route existing in almost all living organisms. Organic acids in the TCA cycle include citric acid, α-ketoglutaric acid, succinic acid, fumaric acid, l-malic acid, and oxaloacetate, which are building-block chemicals with wide applications and huge markets. In this review, we summarize the synthesis pathways of these organic acids and review recent advances in metabolic engineering strategies that enhance organic acid production. We also propose further improvements for the production of organic acids with systems and synthetic biology-guided metabolic engineering strategies. PMID:25902192

  11. The Measurement of the Solar Spectral Irradiance Variability during the Solar Cycle 24 using SOLAR/SOLSPEC on ISS

    NASA Astrophysics Data System (ADS)

    Bolsée, David; Pereira, Nuno; Pandey, Praveen; Cessateur, Gaël; Gillotay, Didier; Foujols, Thomas; Hauchecorne, Alain; Bekki, Slimane; Marchand, Marion; Damé, Luc; Meftah, Mustapha; Bureau, Jerôme

    2016-04-01

    Since April 2008, SOLAR/SOLSPEC measures the Solar Spectral Irradiance (SSI) from 166 nm to 3088 nm. The instrument is a part of the Solar Monitoring Observatory (SOLAR) payload, externally mounted on the Columbus module of the International Space Station. As the SSI is a key input for the validation of solar physics models, together with playing a role in the climate system and photochemistry of the Earth atmosphere, SOLAR/SOLSPEC spectral measurements becomes important. In this study, the in-flight operations and performances of the instrument -including the engineering corrections- will be presented for seven years of the SOLAR mission. Following an accurate absolute calibration, the SSI variability in the UV as measured by SOLAR/SOLSPEC in the course of the solar cycle 24 will be presented and compared to other instruments. The accuracy of these measurements will be also discussed here.

  12. International Solar Cycle Studies [ISCS] Working Group 2: solar magnetic field variability - from the lower atmosphere through the inner corona

    NASA Astrophysics Data System (ADS)

    Harrison, Richard A.; Michels, Donald

    This report is a summary of activities and plans relating to the International Solar Cycle Studies (ISCS) Working Group 2, which is concerned with solar magnetic field variability, from the lower atmosphere through the inner corona. Whilst the Working Group carries a rather general title, the activities are focusing on several well defined topics - in particular the onset of coronal mass ejection events. Recognising the large number of scientific meetings worldwide, the working style of this group is aimed at improving communication, information exchange and collaboration making use of existing meetings and with a minimum of red tape. The core of the activity is through the use of the World Wide Web and e-mail. In this way, this Working Group does not introduce extra effort, but provides a better focus for on-going projects.

  13. Hydrobiology in the Cabo Frio (Brazil) upwelling: two-dimensional structure and variability during a wind cycle

    NASA Astrophysics Data System (ADS)

    Valentin, Jean L.; Andre, Dalmo L.; Jacob, Salvador A.

    1987-01-01

    A study of the variability of hydrobiological parameters in a vertical section during .. wind cycle allowed us to investigate the structure and dynamics of the upwelling ecosystem at Cabo Frio (Brazil). This coastal upwelling system is extremely sensitive to wind changes with nutrient-rich water reaching the surface under NE winds along a coastal belt less than 5 km wide. This narrow strip is dominated by great hydrological instability. Above the continental shelf the upwelling of cold water is characterized by the inclination of the thermocline, whose vertical oscillation determines the main factors of planktonic fluctuations through the water column. After reaching the surface the deep water induces new production which spreads up to 20 km offshore. From a general point of view, pigment richness would fit a quadratic function of general hydrologic conditions. However, this function is only useful at the given collecting point, and within the limits of the amplitude of the hydrological variations.

  14. Beat-to-beat cycle length variability of spontaneously beating guinea pig sinoatrial cells: relative contributions of the membrane and calcium clocks.

    PubMed

    Zaniboni, Massimiliano; Cacciani, Francesca; Lux, Robert L

    2014-01-01

    The heartbeat arises rhythmically in the sino-atrial node (SAN) and then spreads regularly throughout the heart. The molecular mechanism underlying SAN rhythm has been attributed by recent studies to the interplay between two clocks, one involving the hyperpolarization activated cation current If (the membrane clock), and the second attributable to activation of the electrogenic NaCa exchanger by spontaneous sarcoplasmic releases of calcium (the calcium clock). Both mechanisms contain, in principle, sources of beat-to-beat cycle length variability, which can determine the intrinsic variability of SAN firing and, in turn, contribute to the heart rate variability. In this work we have recorded long sequences of action potentials from patch clamped guinea pig SAN cells (SANCs) perfused, in turn, with normal Tyrode solution, with the If inhibitor ivabradine (3 µM), then back to normal Tyrode, and again with the ryanodine channels inhibitor ryanodine (3 µM). We have found that, together with the expected increase in beating cycle length (+25%), the application of ivabradine brought about a significant and dramatic increase in beat-to-beat cycle length variability (+50%). Despite the similar effect on firing rate, ryanodine did not modify significantly beat-to-beat cycle length variability. Acetylcholine was also applied and led to a 131% increase of beating cycle length, with only a 70% increase in beat-to-beat cycle length variability. We conclude that the main source of inter-beat variability of SANCs firing rate is related to the mechanism of the calcium clock, whereas the membrane clock seems to act in stabilizing rate. Accordingly, when the membrane clock is silenced by application of ivabradine, stochastic variations of the calcium clock are free to make SANCs beating rhythm more variable. PMID:24940609

  15. Beat-to-Beat Cycle Length Variability of Spontaneously Beating Guinea Pig Sinoatrial Cells: Relative Contributions of the Membrane and Calcium Clocks

    PubMed Central

    Zaniboni, Massimiliano; Cacciani, Francesca; Lux, Robert L.

    2014-01-01

    The heartbeat arises rhythmically in the sino-atrial node (SAN) and then spreads regularly throughout the heart. The molecular mechanism underlying SAN rhythm has been attributed by recent studies to the interplay between two clocks, one involving the hyperpolarization activated cation current If (the membrane clock), and the second attributable to activation of the electrogenic NaCa exchanger by spontaneous sarcoplasmic releases of calcium (the calcium clock). Both mechanisms contain, in principle, sources of beat-to-beat cycle length variability, which can determine the intrinsic variability of SAN firing and, in turn, contribute to the heart rate variability. In this work we have recorded long sequences of action potentials from patch clamped guinea pig SAN cells (SANCs) perfused, in turn, with normal Tyrode solution, with the If inhibitor ivabradine (3 µM), then back to normal Tyrode, and again with the ryanodine channels inhibitor ryanodine (3 µM). We have found that, together with the expected increase in beating cycle length (+25%), the application of ivabradine brought about a significant and dramatic increase in beat-to-beat cycle length variability (+50%). Despite the similar effect on firing rate, ryanodine did not modify significantly beat-to-beat cycle length variability. Acetylcholine was also applied and led to a 131% increase of beating cycle length, with only a 70% increase in beat-to-beat cycle length variability. We conclude that the main source of inter-beat variability of SANCs firing rate is related to the mechanism of the calcium clock, whereas the membrane clock seems to act in stabilizing rate. Accordingly, when the membrane clock is silenced by application of ivabradine, stochastic variations of the calcium clock are free to make SANCs beating rhythm more variable. PMID:24940609

  16. Mode change of millennial CO2 variability during the last glacial cycle associated with a bipolar marine carbon seesaw.

    PubMed

    Bereiter, Bernhard; Lüthi, Dieter; Siegrist, Michael; Schüpbach, Simon; Stocker, Thomas F; Fischer, Hubertus

    2012-06-19

    Important elements of natural climate variations during the last ice age are abrupt temperature increases over Greenland and related warming and cooling periods over Antarctica. Records from Antarctic ice cores have shown that the global carbon cycle also plays a role in these changes. The available data shows that atmospheric CO(2) follows closely temperatures reconstructed from Antarctic ice cores during these variations. Here, we present new high-resolution CO(2) data from Antarctic ice cores, which cover the period between 115,000 and 38,000 y before present. Our measurements show that also smaller Antarctic warming events have an imprint in CO(2) concentrations. Moreover, they indicate that during Marine Isotope Stage (MIS) 5, the peak of millennial CO(2) variations lags the onset of Dansgaard/Oeschger warmings by 250 ± 190 y. During MIS 3, this lag increases significantly to 870 ± 90 y. Considerations of the ocean circulation suggest that the millennial variability associated with the Atlantic Meridional Overturning Circulation (AMOC) undergoes a mode change from MIS 5 to MIS 4 and 3. Ocean carbon inventory estimates imply that during MIS 3 additional carbon is derived from an extended mass of carbon-enriched Antarctic Bottom Water. The absence of such a carbon-enriched water mass in the North Atlantic during MIS 5 can explain the smaller amount of carbon released to the atmosphere after the Antarctic temperature maximum and, hence, the shorter lag. Our new data provides further constraints for transient coupled carbon cycle-climate simulations during the entire last glacial cycle. PMID:22675123

  17. Thermocline temperature variability in the Timor Strait over the last two glacial cycles

    NASA Astrophysics Data System (ADS)

    Lo Giudice Cappelli, E.; Holbourn, A. E.; Kuhnt, W.; Regenberg, M.; Garbe-Schoenberg, C.

    2012-12-01

    ), corresponding to a temperature difference of ±0.9°C. The amplitude of the temperature change during deglaciation is ~2°C between MIS2 and the Holocene and ~3°C between MIS6 and MIS5e. In contrast, the highest amplitude variability (~6.5°C) is detected during MIS3, suggesting transient shutdown of the Indonesian Throughflow leading to thermocline warming.

  18. Microstructural Features Controlling the Variability in Low-Cycle Fatigue Properties of Alloy Inconel 718DA at Intermediate Temperature

    NASA Astrophysics Data System (ADS)

    Texier, Damien; Gómez, Ana Casanova; Pierret, Stéphane; Franchet, Jean-Michel; Pollock, Tresa M.; Villechaise, Patrick; Cormier, Jonathan

    2016-03-01

    The low-cycle fatigue behavior of two direct-aged versions of the nickel-based superalloy Inconel 718 (IN718DA) was examined in the low-strain amplitude regime at intermediate temperature. High variability in fatigue life was observed, and abnormally short lifetimes were systematically observed to be due to crack initiation at (sub)-surface non-metallic inclusions. However, crack initiation within (sub)-surface non-metallic inclusions did not necessarily lead to short fatigue life. The macro- to micro-mechanical mechanisms of deformation and damage have been examined by means of detailed microstructural characterization, tensile and fatigue mechanical tests, and in situ tensile testing. The initial stages of crack micro-propagation from cracked non-metallic particles into the surrounding metallic matrix occupies a large fraction of the fatigue life and requires extensive local plastic straining in the matrix adjacent to the cracked inclusions. Differences in microstructure that influence local plastic straining, i.e., the δ-phase content and the grain size, coupled with the presence of non-metallic inclusions at the high end of the size distribution contribute strongly to the fatigue life variability.

  19. Advanced Shock Position Control for Mode Transition in a Turbine Based Combined Cycle Engine Inlet Model

    NASA Technical Reports Server (NTRS)

    Csank, Jeffrey T.; Stueber, Thomas J.

    2013-01-01

    A dual flow-path inlet system is being tested to evaluate methodologies for a Turbine Based Combined Cycle (TBCC) propulsion system to perform a controlled inlet mode transition. Prior to experimental testing, simulation models are used to test, debug, and validate potential control algorithms. One simulation package being used for testing is the High Mach Transient Engine Cycle Code simulation, known as HiTECC. This paper discusses the closed loop control system, which utilizes a shock location sensor to improve inlet performance and operability. Even though the shock location feedback has a coarse resolution, the feedback allows for a reduction in steady state error and, in some cases, better performance than with previous proposed pressure ratio based methods. This paper demonstrates the design and benefit with the implementation of a proportional-integral controller, an H-Infinity based controller, and a disturbance observer based controller.

  20. The use of advanced mass spectrometry to dissect the life-cycle of photosystem II

    DOE PAGESBeta

    Weisz, Daniel A.; Gross, Michael L.; Pakrasi, Himadri B.

    2016-05-10

    Photosystem II (PSII) is a photosynthetic membrane-protein complex that undergoes an intricate, tightly regulated cycle of assembly, damage, and repair. The available crystal structures of cyanobacterial PSII are an essential foundation for understanding PSII function, but nonetheless provide a snapshot only of the active complex. To study aspects of the entire PSII life-cycle, mass spectrometry (MS) has emerged as a powerful tool that can be used in conjunction with biochemical techniques. In this article, we present the MS-based approaches that are used to study PSII composition, dynamics, and structure, and review the information about the PSII life-cycle that has beenmore » gained by these methods. This information includes the composition of PSII subcomplexes, discovery of accessory PSII proteins, identification of post-translational modifications and quantification of their changes under various conditions, determination of the binding site of proteins not observed in PSII crystal structures, conformational changes that underlie PSII functions, and identification of water and oxygen channels within PSII. Lastly, we conclude with an outlook for the opportunity of future MS contributions to PSII research.« less

  1. The Use of Advanced Mass Spectrometry to Dissect the Life-Cycle of Photosystem II.

    PubMed

    Weisz, Daniel A; Gross, Michael L; Pakrasi, Himadri B

    2016-01-01

    Photosystem II (PSII) is a photosynthetic membrane-protein complex that undergoes an intricate, tightly regulated cycle of assembly, damage, and repair. The available crystal structures of cyanobacterial PSII are an essential foundation for understanding PSII function, but nonetheless provide a snapshot only of the active complex. To study aspects of the entire PSII life-cycle, mass spectrometry (MS) has emerged as a powerful tool that can be used in conjunction with biochemical techniques. In this article, we present the MS-based approaches that are used to study PSII composition, dynamics, and structure, and review the information about the PSII life-cycle that has been gained by these methods. This information includes the composition of PSII subcomplexes, discovery of accessory PSII proteins, identification of post-translational modifications and quantification of their changes under various conditions, determination of the binding site of proteins not observed in PSII crystal structures, conformational changes that underlie PSII functions, and identification of water and oxygen channels within PSII. We conclude with an outlook for the opportunity of future MS contributions to PSII research. PMID:27242823

  2. The Use of Advanced Mass Spectrometry to Dissect the Life-Cycle of Photosystem II

    PubMed Central

    Weisz, Daniel A.; Gross, Michael L.; Pakrasi, Himadri B.

    2016-01-01

    Photosystem II (PSII) is a photosynthetic membrane-protein complex that undergoes an intricate, tightly regulated cycle of assembly, damage, and repair. The available crystal structures of cyanobacterial PSII are an essential foundation for understanding PSII function, but nonetheless provide a snapshot only of the active complex. To study aspects of the entire PSII life-cycle, mass spectrometry (MS) has emerged as a powerful tool that can be used in conjunction with biochemical techniques. In this article, we present the MS-based approaches that are used to study PSII composition, dynamics, and structure, and review the information about the PSII life-cycle that has been gained by these methods. This information includes the composition of PSII subcomplexes, discovery of accessory PSII proteins, identification of post-translational modifications and quantification of their changes under various conditions, determination of the binding site of proteins not observed in PSII crystal structures, conformational changes that underlie PSII functions, and identification of water and oxygen channels within PSII. We conclude with an outlook for the opportunity of future MS contributions to PSII research. PMID:27242823

  3. Application of a Tractive Energy Analysis to Quantify the Benefits of Advanced Efficiency Technologies Using Characteristic Drive Cycle Data

    SciTech Connect

    LaClair, Tim J

    2012-01-01

    Accurately predicting the fuel savings that can be achieved with the implementation of various technologies developed for fuel efficiency can be very challenging, particularly when considering combinations of technologies. Differences in the usage of highway vehicles can strongly influence the benefits realized with any given technology, which makes generalizations about fuel savings inappropriate for different vehicle applications. A model has been developed to estimate the potential for reducing fuel consumption when advanced efficiency technologies, or combinations of these technologies, are employed on highway vehicles, particularly medium- and heavy-duty trucks. The approach is based on a tractive energy analysis applied to drive cycles representative of the vehicle usage, and the analysis specifically accounts for individual energy loss factors that characterize the technologies of interest. This tractive energy evaluation is demonstrated by analyzing measured drive cycles from a long-haul trucking fleet and the results of an assessment of the fuel savings potential for combinations of technologies are presented. The results of this research will enable more reliable estimates of the fuel savings benefits that can be realized with particular technologies and technology combinations for individual trucking applications so that decision makers can make informed investment decisions for the implementation of advanced efficiency technologies.

  4. Safeguards and Non-proliferation Issues as Related to Advanced Fuel Cycle and Advanced Fast Reactor Development with Processing of Reactor Fuel

    SciTech Connect

    Rahmat Aryaeinejad; Jerry D. Cole; Mark W. Drigert; Dee E. Vaden

    2006-10-01

    The goal of this work is to establish basic data and techniques to enable safeguards appropriate to a new generation of nuclear power systems that will be based on fast spectrum reactors and mixed actinide fuels containing significant quantities of "minor" actinides, possibly due to reprocessing, and determination of what new radiation signatures and parameters need to be considered. The research effort focuses on several problems associated with the use of fuel having significantly different actinide inventories that current practice and on the development of innovative techniques using new radiation signatures and other parameters useful for safeguards and monitoring. In addition, the development of new distinctive radiation signatures as an aid in controlling proliferation of nuclear materials has parallel applications to support Gen-IV and current advanced fuel cycle initiative (AFCI) goals as well as the anticipated Global Nuclear Energy Partnership (GNEP).

  5. A Comparative Analysis of Dietary Habits on Sensory Motor Association and Heart Rate Variability during Menstrual Cycle

    PubMed Central

    Alam, Tanwir; Jiwane, Rekha; Kishanrao, Sadawarte Sahebrao

    2016-01-01

    Introduction Dietary habits can make a big difference on both physical and mental aspects of the body. Menstrual disorder frequently affects the quality of life of adolescent and young adult women. Menstrual cycle irregularities may be associated with psychological stress, and endocrine disturbances. Monitoring of sensory-motor association and cardiovascular activity across the menstrual cycle has not been evaluated with dietary habits. Aim The present study was carried out to bridge the relationship between dietary habits and endogenous sex hormone mediated sensory motor association and heart rate variability (HRV) among young females during different phases of menstrual cycle. Materials and Methods The present study was carried out on healthy volunteered 100 female medical students in the age group of 19-25 years with regular menstrual cycle. Group I (n=45) vegetarians, Group II (n=25) eggetarians and Group III (n= 30) non-vegetarians, where n denotes the number of individuals in each group. Sensory-motor association (reaction time) and cardiovascular activity (HRV) was evaluated. Results We observed among all the dietary habits (vegetarians, eggetarians and non-vegetarians) the reaction time and HRV was comparable in follicular and menstrual phase, however it was significantly altered in luteal phase when compared to follicular and menstrual phase. Moreover, among all the dietary habits, non-vegetarians showed more significant alteration of reaction time and HRV in luteal phase when compared to vegetarians and eggetarians, as well as there was positive correlation between visual and auditory reaction time and negative correlation between LF and HF in luteal phase, among all the dietary habits. Conclusion We concluded sensorimotor association and regulation of autonomic tone is modified in luteal phase comparable to follicular phase and menstrual phase; however non-vegetarian had showed more significant alterations as compared to eggetarians and vegetarians

  6. The Semantico-Functional Variability of Words and the Teaching of Vocabulary to advanced ESL Students.

    ERIC Educational Resources Information Center

    Kerim-Zade, Irina; Pavlov, Vladimir

    1989-01-01

    Attempts to explore one of the aspects of the systematic organization of the English lexicon: semantico-functional variability. It is concluded that the teaching of English vocabulary should include the teaching of rules concerning the semantico-functional variability of words. (Author/VWL)

  7. Prior Knowledge or Advance Organizers as Effective Variables in Chemical Learning

    ERIC Educational Resources Information Center

    Fensham, P. J.; West, L. H. T.

    1976-01-01

    This report describes an attempt to apply a critical empirical test to some predictions from Ausubel's theory concerning the subsuming role of advance organizers. Alternative explanations are proposed and subsequent predictions tested. (BT)

  8. An assessment of the effect on Olkiluoto repository capacity achievable with advanced fuel cycles

    SciTech Connect

    Juutilainen, P.; Viitanen, T.

    2013-07-01

    Previously a few scenarios have been simulated for transition from thermal to fast reactor fleet in Finland in order to determine how much the transuranic inventory could be reduced with the partitioning and transmutation (P-T) technologies. Those calculations, performed with COSI6 code developed by CEA, are extended in the present study, in which the effect of P-T on the capacity of the planned final disposal repository at Olkiluoto (Finland) is evaluated by taking into account the created fission products and transuranic residuals from the reprocessing operations. The decay heat is assumed to be the most restrictive factor in defining the waste disposal packing density. The repository capacity evaluation of this study is based on the comparison of the decay heats produced by the deposited waste in various scenarios. The reference scenario of this article involves only Light Water Reactors (LWR) in an open fuel cycle. The capacity requirement of the geological repository is estimated in a few closed fuel cycle scenarios, all including actinide transmutation with Fast Reactors (FR). The comparison between the P-T scenarios and reference is based on the decay heat production of the deposited waste. The COSI6 code is used for simulations to provide the repository decay heat curves. Applying the closed fuel cycle would change the disposal concept and schedule, because of which it is not quite straightforward to assess the impact of P-T on the capacity. However, it can be concluded that recycling the transuranic nuclides probably decreases the required volume for the disposal, but thermal dimensioning analysis is needed for more specific conclusions.

  9. FURTHER ASSESSMENTS OF THE ATTRACTIVENESS OF MATERIALS IN ADVANCED NUCLEAR FUEL CYCLES FROM A SAFEGUARDS PERSPECTIVE

    SciTech Connect

    Bathke, C. G.; Jarvinen, G. D.; Wallace, R. K.; Ireland, J. R.; Johnson, M. W.; Sleaford, Brad W.; Ebbinghaus, B. B.; Bradley, Keith S.; Collins, Brian A.; Smith, Brian W.; Prichard, Andrew W.

    2008-10-01

    This paper summarizes the results of an extension to an earlier study [ ] that examined the attractiveness of materials mixtures containing special nuclear materials (SNM) associated with the PUREX, UREX+, and COEX reprocessing schemes. This study focuses on the materials associated with the UREX, COEX, THOREX, and PYROX reprocessing schemes. This study also examines what is required to render plutonium as “unattractive.” Furthermore, combining the results of this study with those from the earlier study permits a comparison of the uranium and thorium based fuel cycles on the basis of the attractiveness of the SNM associated with each fuel cycle. Both studies were performed at the request of the United States Department of Energy (DOE), and are based on the calculation of “attractiveness levels” that has been couched in terms chosen for consistency with those normally used for nuclear materials in DOE nuclear facilities [ ]. The methodology and key findings will be presented. Additionally, how these attractiveness levels relate to proliferation resistance (e.g. by increasing impediments to the diversion, theft, undeclared production of SNM for the purpose of acquiring a nuclear weapon), and how they could be used to help inform policy makers, will be discussed.

  10. Advanced Fuel Cycle Initiative AFC-1D, AFC-1G and AFC-1H End of FY-06 Irradiation Report

    SciTech Connect

    Advanced Fuel Cycle Initiative AFC-1D, AFC-1G and

    2006-09-01

    The U. S. Advanced Fuel Cycle Initiative (AFCI) seeks to develop and demonstrate the technologies needed to transmute the long-lived transuranic actinide isotopes contained in spent nuclear fuel into shorter-lived fission products, thereby dramatically decreasing the volume of material requiring disposition and the long-term radiotoxity and heat load of high-level waste sent to a geologic repository. The AFC-1 irradiation experiments on transmutation fuels are expected to provide irradiation performance data on non-fertile and low-fertile fuel forms specifically, irradiation growth and swelling, helium production, fission gas release, fission product and fuel constituent migration, fuel phase equilibria, and fuel-cladding chemical interaction. Contained in this report are the to-date physics evaluations performed on three of the AFC-1 experiments; AFC-1D, AFC-1G and AFC-1H. The AFC-1D irradiation experiment consists of metallic non-fertile fuel compositions with minor actinides for potential use in accelerator driven systems and AFC-1G and AFC-1H irradiation experiments are part of the fast neutron reactor fuel development effort. The metallic fuel experiments and nitride experiment are high burnup analogs to previously irradiated experiments and are to be irradiated to = 40 at.% burnup and = 25 at.% burnup, respectively. Based on the results of the physics evaluations it has been determined that the AFC-1D experiment will remain in the ATR for approximately 4 additional cycles, the AFC-1G experiment for an additional 4-5 cycles, and the AFC-1H experiment for approximately 8 additional cycles, in order to reach the desired programmatic burnup. The specific irradiation schedule for these tests will be determined based on future physics evaluations and all results will be documented in subsequent reports.

  11. A record of the variability of climate transitions between the last four glacial cycles from high-precision speleothem chronology

    NASA Astrophysics Data System (ADS)

    Polyak, V. J.; Asmerom, Y.; Lachniet, M. S.; Lapointe, Z. C.

    2011-12-01

    Speleothem growth in Fort Stanton Cave, central New Mexico in southwestern North America (SWNA), occurred predominantly during glacial periods for the last four glacial cycles, with some, but little growth spilling over into the glacial termination events. Given that lacustrine records show that glacial periods are pluvial periods in SWNA, Fort Stanton Cave speleothem growth seems to be a faithful indicator of periods of greater effective moisture for SWNA. Likewise, Asmerom et al. (2010) provided the first stable isotope record from a Fort Stanton stalagmite (FS-2) and reported an oxygen isotope record between 11.4 and 56 ka that closely mimicked the Greenland ice core oxygen records over much of the last glacial period. The δ18O variation in FS-2 reflected changes in the amount of winter precipitation, which in turn reflected the position of the Polar Jet Stream in response to changes in Northern Hemisphere temperature gradient. In contrast, variations in δ13C primarily reflect changes in the amount and type of vegetation which is linked to changes in local aridity. The stalagmites from this cave have high uranium, high δ234U and low detritus thorium and are thus ideally suited for dating using the uranium-series technique. Here we present a record of climate variability for the previous four ice ages. Based on growth of multiple stalagmites, we define the period from ~60 to 14.5 ka as speleothem-based pluvial 1 (SWNA-P1). Speleothems FS-5, FS-6, TR-2, TR-3 and HH-1 grew during glacial cycles 2-4, which we define as pluvials 2, 3, & 4 (SWNA-P2, P3, and P4) where preliminary results suggest that SWNA-P2 lasted from 170 to 130 ka, SWNA-P3 from 265 to 242 ka, and SWNA-P4 from 352 to 336 ka. Growth hiatuses and the carbon isotope records indicate the timing of pluvial terminations. Overall, SWNA-P3 is more similar to SWNA-P1, showing events that may have been more complex, with both exhibiting stadial- and interstadial-like climatic signals, while SWNA-P2 and P4

  12. Life cycle assessment of advanced bioethanol production from pulp and paper sludge.

    PubMed

    Sebastião, Diogo; Gonçalves, Margarida S; Marques, Susana; Fonseca, César; Gírio, Francisco; Oliveira, Ana C; Matos, Cristina T

    2016-05-01

    This work evaluates the environmental performance of using pulp and paper sludge as feedstock for the production of second generation ethanol. An ethanol plant for converting 5400 tons of dry sludge/year was modelled and evaluated using a cradle-to-gate life cycle assessment approach. The sludge is a burden for pulp and paper mills that is mainly disposed in landfilling. The studied system allows for the valorisation of the waste, which due to its high polysaccharide content is a valuable feedstock for bioethanol production. Eleven impact categories were analysed and the results showed that enzymatic hydrolysis and neutralisation of the CaCO3 are the environmental hotspots of the system contributing up to 85% to the overall impacts. Two optimisation scenarios were evaluated: (1) using a reduced HCl amount in the neutralisation stage and (2) co-fermentation of xylose and glucose, for maximal ethanol yield. Both scenarios displayed significant environmental impact improvements. PMID:26926202

  13. Air Evaporation closed cycle water recovery technology - Advanced energy saving designs

    NASA Technical Reports Server (NTRS)

    Morasko, Gwyndolyn; Putnam, David F.; Bagdigian, Robert

    1986-01-01

    The Air Evaporation water recovery system is a visible candidate for Space Station application. A four-man Air Evaporation open cycle system has been successfully demonstrated for waste water recovery in manned chamber tests. The design improvements described in this paper greatly enhance the system operation and energy efficiency of the air evaporation process. A state-of-the-art wick feed design which results in reduced logistics requirements is presented. In addition, several design concepts that incorporate regenerative features to minimize the energy input to the system are discussed. These include a recuperative heat exchanger, a heat pump for energy transfer to the air heater, and solar collectors for evaporative heat. The addition of the energy recovery devices will result in an energy reduction of more than 80 percent over the systems used in earlier manned chamber tests.

  14. Advanced Technology Inlet Design, NRA 8-21 Cycle II: DRACO Flowpath Hypersonic Inlet Design

    NASA Technical Reports Server (NTRS)

    Sanders, Bobby W.; Weir, Lois J.

    1999-01-01

    The report outlines work performed in support of the flowpath development for the DRACO engine program. The design process initiated to develop a hypersonic axisymmetric inlet for a Mach 6 rocket-based combined cycle (RBCC) engine is discussed. Various design parametrics were investigated, including design shock-on-lip Mach number, cone angle, throat Mach number, throat angle. length of distributed compression, and subsonic diffuser contours. Conceptual mechanical designs consistent with installation into the D-21 vehicle were developed. Additionally, program planning for an intensive inlet development program to support a Critical Design Review in three years was performed. This development program included both analytical and experimental elements and support for a flight-capable inlet mechanical design.

  15. The Variability of Solar Spectral Irradiance and Solar Surface Indices Through the Solar Activity Cycles 21-23

    NASA Astrophysics Data System (ADS)

    Deniz Goker, Umit

    2016-07-01

    A study of variations of solar spectral irradiance (SSI) in the wavelength ranges 121.5 nm-300.5 nm for the period 1981-2009 is presented. We used various data for ultraviolet (UV) spectral lines and international sunspot number (ISSN) from interactive data centers as SME (NSSDC), UARS (GDAAC), SORCE (LISIRD) and SIDC, respectively. We developed a special software for extracting the data and reduced this data by using the MATLAB. In this respect, we revealed negative correlations of intensities of UV (289.5 nm-300.5 nm) emission lines originating in the solar chromosphere with the ISSN index during the unusually prolonged minimum between the solar cycles (SCs) 23 and 24. We also compared our results with the ground-based telescopes as Solar Irradiance Platform, Stanford Data (SFO), Kodaikanal Data (KKL) and NGDC Homepage (Rome and Learmonth Solar Observatories). We studied the variations of total solar irradiance (TSI), magnetic field, sunspots/sunspot groups, Ca II K-flux, faculae and plage areas data with these ground-based telescopes, respectively. We reduced the selected data using the Phyton programming language and plot with the IDL programme. Therefore, we found that there was a decrease in the area of bright faculae and chromospheric plages while the percentage of dark faculae and plage decrease, as well. However, these decreases mainly occurred in small sunspots, contrary to this, these terms in large sunspot groups were comparable to previous SCs or even larger. Nevertheless, negative correlations between ISSN and SSI data indicate that these emissions are in close connection with the classes of sunspots/sunspot groups and "PLAGE" regions. Finally, we applied the time series of the chemical elements correspond to the wavelengths 121.5 nm-300.5 nm and compared with the ISSN data. We found an unexpected increasing in the 298.5 nm for the Fe II element. The variability of Fe II (298.5 nm) is in close connection with the plage regions and the sizes of the

  16. Contracts, grants and funding summary of supersonic cruise research and variable-cycle engine technology programs, 1972 - 1982

    NASA Technical Reports Server (NTRS)

    Hoffman, S.; Varholic, M. C.

    1983-01-01

    NASA-SCAR (AST) program was initiated in 1972 at the direct request of the Executive Office of the White House and Congress following termination of the U.S. SST program. The purpose of SCR was to conduct a focused research and technology program on those technology programs which contributed to the SST termination and, also, to provide an expanded data base for future civil and military supersonic transport aircraft. Funding for the Supersonic Cruise Research (SCR) Program was initiated in fiscal year 1973 and terminated in fiscal year 1981. The program was implemented through contracts and grants with industry, universities, and by in-house investigations at the NASA/OAST centers. The studies included system studies and five disciplines: propulsion, stratospheric emissions impact, materials and structures, aerodynamic performance, and stability and control. The NASA/Lewis Variable-Cycle Engine (VCE) Component Program was initiated in 1976 to augment the SCR program in the area of propulsion. After about 2 years, the title was changed to VCE Technology program. The total number of contractors and grantees on record at the AST office in 1982 was 101 for SCR and 4 for VCE. This paper presents a compilation of all the contracts and grants as well as the funding summaries for both programs.

  17. Experimental aerodynamic and acoustic model testing of the Variable Cycle Engine (VCE) testbed coannular exhaust nozzle system

    NASA Technical Reports Server (NTRS)

    Nelson, D. P.; Morris, P. M.

    1980-01-01

    Aerodynamic performance and jet noise characteristics of a one sixth scale model of the variable cycle engine testbed exhaust system were obtained in a series of static tests over a range of simulated engine operating conditions. Model acoustic data were acquired. Data were compared to predictions of coannular model nozzle performance. The model, tested with an without a hardwall ejector, had a total flow area equivalent to a 0.127 meter (5 inch) diameter conical nozzle with a 0.65 fan to primary nozzle area ratio and a 0.82 fan nozzle radius ratio. Fan stream temperatures and velocities were varied from 422 K to 1089 K (760 R to 1960 R) and 434 to 755 meters per second (1423 to 2477 feet per second). Primary stream properties were varied from 589 to 1089 K (1060 R to 1960 R) and 353 to 600 meters per second (1158 to 1968 feet per second). Exhaust plume velocity surveys were conducted at one operating condition with and without the ejector installed. Thirty aerodynamic performance data points were obtained with an unheated air supply. Fan nozzle pressure ratio was varied from 1.8 to 3.2 at a constant primary pressure ratio of 1.6; primary pressure ratio was varied from 1.4 to 2.4 while holding fan pressure ratio constant at 2.4. Operation with the ejector increased nozzle thrust coefficient 0.2 to 0.4 percent.

  18. Prediction Model for Prevalence and Incidence of Advanced Age-Related Macular Degeneration Based on Genetic, Demographic, and Environmental Variables

    PubMed Central

    Seddon, Johanna M.; Reynolds, Robyn; Maller, Julian; Fagerness, Jesen A.; Daly, Mark J.; Rosner, Bernard

    2013-01-01

    Purpose The joint effects of genetic, ocular, and environmental variables were evaluated and predictive models for prevalence and incidence of AMD were assessed. Methods Participants in the multicenter Age-Related Eye Disease Study (AREDS) were included in a prospective evaluation of 1446 individuals, of which 279 progressed to advanced AMD (geographic atrophy or neovascular disease) and 1167 did not progress during 6.3 years of follow-up. For prevalent AMD, 509 advanced cases were compared with 222 controls. Covariates for the incidence analysis included age, sex, education, smoking, body mass index (BMI), baseline AMD grade, and the AREDS vitamin–mineral treatment assignment. DNA specimens were evaluated for six variants in five genes related to AMD. Unconditional logistic regression analyses were performed for prevalent and incident advanced AMD. An algorithm was developed and receiver operating characteristic curves and C statistics were calculated to assess the predictive ability of risk scores to discriminate progressors from nonprogressors. Results All genetic polymorphisms were independently related to prevalence of advanced AMD, controlling for genetic factors, smoking, BMI, and AREDS treatment. Multivariate odds ratios (ORs) were 3.5 (95% confidence interval [CI], 1.7–7.1) for CFH Y402H; 3.7 (95% CI, 1.6 – 8.4) for CFH rs1410996; 25.4 (95% CI, 8.6 –75.1) for LOC387715 A69S (ARMS2); 0.3 (95% CI, 0.1– 0.7) for C2 E318D; 0.3 (95% CI, 0.1– 0.5) for CFB; and 3.6 (95% CI, 1.4 –9.4) for C3 R102G, comparing the homozygous risk/protective genotypes to the referent genotypes. For incident AMD, all these variants except CFB were significantly related to progression to advanced AMD, after controlling for baseline AMD grade and other factors, with ORs from 1.8 to 4.0 for presence of two risk alleles and 0.4 for the protective allele. An interaction was seen between CFH402H and treatment, after controlling for all genotypes. Smoking was independently

  19. Advanced air separation for coal gasification-combined-cycle power plants: Final report

    SciTech Connect

    Kiersz, D.F.; Parysek, K.D.; Schulte, T.R.; Pavri, R.E.

    1987-08-01

    Union Carbide Corporation (UCC) and General Electric Company (GE) conducted a study to determine the benefits associated with extending the integration of integrated coal gasification-combined cycle (IGCC) systems to include the air separation plant which supplies oxygen to the gasifiers. This is achieved by extracting air from the gas turbine air compressors to feed the oxygen plant and returning waste nitrogen to the gas turbine. The ''Radiant Plus Convective Design'' (59/sup 0/F ambient temperature case) defined in EPRI report AP-3486 was selected as a base case into which the oxygen plant-gas turbine integration was incorporated and against which it was compared. General Electric Company's participation in evaluating gas turbine and power block performance ensured consistency between EPRI report AP-3486 and this study. Extending the IGCC integration to include an integrated oxygen plant-gas turbine results in a rare combination of benefits - higher efficiency and lower capital costs. Oxygen plant capital costs are over 20% less and the power requirement is reduced significantly. For the IGCC system, the net power output is higher for the same coal feed rate; this results in an overall improvement in heat rate of about 2% coupled with a reduction in capital costs of 2 to 3%. 6 refs., 11 figs., 7 tabs.

  20. THE ATTRACTIVENESS OF MATERIALS IN ADVANCED NUCLEAR FUEL CYCLES FOR VARIOUS PROLIFERATION AND THEFT SCENARIOS

    SciTech Connect

    Bathke, C. G.; Ebbinghaus, Bartley B.; Collins, Brian A.; Sleaford, Brad W.; Hase, Kevin R.; Robel, Martin; Wallace, R. K.; Bradley, Keith S.; Ireland, J. R.; Jarvinen, G. D.; Johnson, M. W.; Prichard, Andrew W.; Smith, Brian W.

    2012-08-29

    We must anticipate that the day is approaching when details of nuclear weapons design and fabrication will become common knowledge. On that day we must be particularly certain that all special nuclear materials (SNM) are adequately accounted for and protected and that we have a clear understanding of the utility of nuclear materials to potential adversaries. To this end, this paper examines the attractiveness of materials mixtures containing SNM and alternate nuclear materials associated with the plutonium-uranium reduction extraction (Purex), uranium extraction (UREX), coextraction (COEX), thorium extraction (THOREX), and PYROX (an electrochemical refining method) reprocessing schemes. This paper provides a set of figures of merit for evaluating material attractiveness that covers a broad range of proliferant state and subnational group capabilities. The primary conclusion of this paper is that all fissile material must be rigorously safeguarded to detect diversion by a state and must be provided the highest levels of physical protection to prevent theft by subnational groups; no 'silver bullet' fuel cycle has been found that will permit the relaxation of current international safeguards or national physical security protection levels. The work reported herein has been performed at the request of the U.S. Department of Energy (DOE) and is based on the calculation of 'attractiveness levels' that are expressed in terms consistent with, but normally reserved for, the nuclear materials in DOE nuclear facilities. The methodology and findings are presented. Additionally, how these attractiveness levels relate to proliferation resistance and physical security is discussed.

  1. Advanced electrolysis development for hydrogen-cycle peak shaving for electric utilities

    SciTech Connect

    Fernandes, R.A.; Nuttall, L.J.

    1982-09-01

    Meeting peak power demands can impose limiting conditions on generation, transmission, and distribution equipment in the electric utility network--especially around urban areas. Utilization of a cost-effective energy storage system capable of being located near the load centers could improve load factors and maximize utilization of installed capital equipment. A hydrogen-cycle peak-shaving system (HCPS) can be sited in populated areas, imposing no environmental concerns, and providing considerable flexibility not only in meeting peak load demands, but also in helping to meet varying system load-growth patterns. Several possible configurations for an HCPS are described, together with a summary of the features and benefits. An alternate ''dispersed'' HCPS system is also described for use by a combined electric and gas utility. One of the key elements in an HCPS system is an efficient, cost-effective water electrolysis unit. The General Electric Company has been working with the Niagara Mohawk Power Company, and others, since 1976 on the development of a unique solid-polymer electrolyte (SPE) electrolysis system which offers considerably higher efficiencies and potentially lower capital cost as compared with conventional commercial alkaline electrolyzers. The current status of this development program is discussed.

  2. Concentrating solar power (CSP) power cycle improvements through application of advanced materials

    NASA Astrophysics Data System (ADS)

    Siefert, John A.; Libby, Cara; Shingledecker, John

    2016-05-01

    Concentrating solar power (CSP) systems with thermal energy storage (TES) capability offer unique advantages to other renewable energy technologies in that solar radiation can be captured and stored for utilization when the sun is not shining. This makes the technology attractive as a dispatchable resource, and as such the Electric Power Research Institute (EPRI) has been engaged in research and development activities to understand and track the technology, identify key technical challenges, and enable improvements to meet future cost and performance targets to enable greater adoption of this carbon-free energy resource. EPRI is also involved with technically leading a consortium of manufacturers, government labs, and research organizations to enable the next generation of fossil fired power plants with advanced ultrasupercritical (A-USC) steam temperatures up to 760°C (1400°F). Materials are a key enabling technology for both of these seemingly opposed systems. This paper discusses how major strides in structural materials for A-USC fossil fired power plants may be translated into improved CSP systems which meet target requirements.

  3. Performance of the fissionTPC and the Potential to Advance the Thorium Fuel Cycle

    NASA Astrophysics Data System (ADS)

    Towell, Rusty; Niffte Collaboration

    2014-09-01

    The NIFFTE fission Time Projection Chamber (fissionTPC) is a powerful tool that is being developed to take precision measurements of neutron-induced fission cross sections of transuranic elements. During the last run at the Los Alamos Neutron Science Center (LANSCE) the fully instrumented TPC took data for the first time. The exquisite tracking capabilities of this device allow the full reconstruction of charged particles produced by neutron beam induced fissions from a thin central target. The wealth of information gained from this approach will allow cross section systematics to be controlled at the level of 1%. The fissionTPC performance from this run will be shared. These results are critical to the development of advanced uranium-fueled reactors. However, there are clear advantages to developing thorium-fueled reactors including the abundance of thorium verses uranium, minimizing radioactive waste, improved reactor safety, and enhanced proliferation resistance. The potential for using the fissionTPC to measure needed cross sections important to the development of thorium fueled nuclear reactors will also be discussed.

  4. Advanced Monitoring to Improve Combustion Turbine/Combined Cycle Reliability, Availability & Maintainability

    SciTech Connect

    Leonard Angello

    2005-09-30

    Power generators are concerned with the maintenance costs associated with the advanced turbines that they are purchasing. Since these machines do not have fully established Operation and Maintenance (O&M) track records, power generators face financial risk due to uncertain future maintenance costs. This risk is of particular concern, as the electricity industry transitions to a competitive business environment in which unexpected O&M costs cannot be passed through to consumers. These concerns have accelerated the need for intelligent software-based diagnostic systems that can monitor the health of a combustion turbine in real time and provide valuable information on the machine's performance to its owner/operators. EPRI, Impact Technologies, Boyce Engineering, and Progress Energy have teamed to develop a suite of intelligent software tools integrated with a diagnostic monitoring platform that, in real time, interpret data to assess the 'total health' of combustion turbines. The 'Combustion Turbine Health Management System' (CTHMS) will consist of a series of 'Dynamic Link Library' (DLL) programs residing on a diagnostic monitoring platform that accepts turbine health data from existing monitoring instrumentation. CTHMS interprets sensor and instrument outputs, correlates them to a machine's condition, provide interpretative analyses, project servicing intervals, and estimate remaining component life. In addition, the CTHMS enables real-time anomaly detection and diagnostics of performance and mechanical faults, enabling power producers to more accurately predict critical component remaining useful life and turbine degradation.

  5. Cycle Life Studies of Advanced Technology Development Program Gen 1 Lithium Ion Batteries

    SciTech Connect

    Wright, Randy Ben; Motloch, Chester George

    2001-03-01

    This report presents the test results of a special calendar-life test conducted on 18650-size, prototype, lithium-ion battery cells developed to establish a baseline chemistry and performance for the Advanced Technology Development Program. As part of electrical performance testing, a new calendar-life test protocol was used. The test consisted of a once-per-day discharge and charge pulse designed to have minimal impact on the cell yet establish the performance of the cell over a period of time such that the calendar life of the cell could be determined. The calendar life test matrix included two states of charge (i.e., 60 and 80%) and four temperatures (40, 50, 60, and 70°C). Discharge and regen resistances were calculated from the test data. Results indicate that both discharge and regen resistance increased nonlinearly as a function of the test time. The magnitude of the discharge and regen resistance depended on the temperature and state of charge at which the test was conducted. The calculated discharge and regen resistances were then used to develop empirical models that may be useful to predict the calendar life or the cells.

  6. Variables in Second Language Attrition: Advancing the State of the Art

    ERIC Educational Resources Information Center

    Bardovi-Harlig, Kathleen; Stringer, David

    2010-01-01

    This article provides a comprehensive synthesis of research on language attrition to date, with a view to establishing a theoretically sound basis for future research in the domain of second language (L2) attrition. We identify the variables that must be tracked in populations who experience language loss, and we develop a general model for the…

  7. Cultural Background Variables in Dance Talent Development: Findings from the UK Centres for Advanced Training

    ERIC Educational Resources Information Center

    Sanchez, Erin N.; Aujla, Imogen J.; Nordin-Bates, Sanna

    2013-01-01

    This study is a qualitative enquiry into cultural background variables--social support, values, race/ethnicity and economic means--in the process of dance talent development. Seven urban dance students in pre-vocational training, aged 15-19, participated in semi-structured interviews. Interviews were inductively analysed using QSR International…

  8. Nonlinguistic Variables in Advanced Second Language Reading: Learners' Self-Assessment and Enjoyment

    ERIC Educational Resources Information Center

    Brantmeier, Cindy

    2005-01-01

    The present study on second language (L2) reading and individual difference variables (IDVs) examines learners' self-assessed ability level and enjoyment and the effects of these factors on two different measures of comprehension. The investigation controls for topic familiarity differences by gender and the study utilizes the authentic short…

  9. Advanced Nonlinear Latent Variable Modeling: Distribution Analytic LMS and QML Estimators of Interaction and Quadratic Effects

    ERIC Educational Resources Information Center

    Kelava, Augustin; Werner, Christina S.; Schermelleh-Engel, Karin; Moosbrugger, Helfried; Zapf, Dieter; Ma, Yue; Cham, Heining; Aiken, Leona S.; West, Stephen G.

    2011-01-01

    Interaction and quadratic effects in latent variable models have to date only rarely been tested in practice. Traditional product indicator approaches need to create product indicators (e.g., x[superscript 2] [subscript 1], x[subscript 1]x[subscript 4]) to serve as indicators of each nonlinear latent construct. These approaches require the use of…

  10. Mountain glacier velocity variation during a retreat-advance cycle quantified using high-precision analysis of ASTER images

    NASA Astrophysics Data System (ADS)

    Anderson, B.; Herman, F.; Leprince, S.

    2009-12-01

    Analysis of optical satellite imagery (ASTER) has revealed the contrasting response of mountain glaciers to similar climatic forcing. High-resolution and near-complete coverage of ice velocities in the central part of the Southern Alps, New Zealand, has been obtained from feature tracking using repeat imagery in 2002 and 2006. Precise orthorectification, co-registration and correlation is carried out using the freely available software COSI-corr. This analysis, combined with short time windows, has enabled velocities to be captured even in the accumulation areas, where velocities are lowest and surface features ephemeral. The results indicate large dynamic changes in some glaciers have occurred between 2002 and 2006. The steep and more responsive Fox and Franz Josef Glaciers increased speed by factors of as much as three during the period, while the low-angled and debris covered Tasman Glacier showed no measurable velocity change. Velocity increases on the steeper glaciers are the result of an observed thickening and steepening of the glacier tongues as the glaciers moved from a retreat phase in 2002 to an advance phase in 2006. This contrasting behaviour is consistent with observed terminus position changes - the steeper glaciers have undergone several advance/retreat cycles during the period of observation (1894 - present) while the low-angled glacier showed little terminus response until retreat resulting from the accelerating growth of a pro-glacial lake in 1983.

  11. Advances in Acid Concentration Membrane Technology for the Sulfur-Iodine Thermochemical Cycle

    SciTech Connect

    Frederick F. Stewart; Christopher J. Orme

    2006-11-01

    One of the most promising cycles for the thermochemical generation of hydrogen is the Sulfur-Iodine (S-I) process, where aqueous HI is thermochemically decomposed into H2 and I2 at approximately 350 degrees Celsius. Regeneration of HI is accomplished by the Bunsen reaction (reaction of SO2, water, and iodine to generate H2SO4 and HI). Furthermore, SO2 is regenerated from the decomposition of H2SO4 at 850 degrees Celsius yielding the SO2 as well as O2. Thus, the cycle actually consists of two concurrent oxidation-reduction loops. As HI is regenerated, co-produced H2SO4 must be separated so that each may be decomposed. Current flowsheets employ a large amount (~83 mol% of the entire mixture) of elemental I2 to cause the HI and the H2SO4 to separate into two phases. To aid in the isolation of HI, which is directly decomposed into hydrogen, water and iodine must be removed. Separation of iodine is facilitated by removal of water. Sulfuric acid concentration is also required to facilitate feed recycling to the sulfuric acid decomposer. Decomposition of the sulfuric acid is an equilibrium limited process that leaves a substantial portion of the acid requiring recycle. Distillation of water from sulfuric acid involves significant corrosion issues at the liquid-vapor interface. Thus, it is desirable to concentrate the acid without boiling. Recent efforts at the INL have concentrated on applying pervaporation through Nafion-117, Nafion-112, and sulfonated poly(etheretherketone) (S-PEEK) membranes for the removal of water from HI/water and HI/Iodine/water feedstreams. In pervaporation, a feed is circulated at low pressure across the upstream side of the membrane, while a vacuum is applied downstream. Selected permeants sorb into the membrane, transport through it, and are vaporized from the backside. Thus, a concentration gradient is established, which provides the driving force for transport. In this work, membrane separations have been performed at temperatures as high as

  12. The need for a characteristics-based approach to radioactive waste classification as informed by advanced nuclear fuel cycles using the fuel-cycle integration and tradeoffs (FIT) model

    SciTech Connect

    Djokic, D.; Piet, S.; Pincock, L.; Soelberg, N.

    2013-07-01

    This study explores the impact of wastes generated from potential future fuel cycles and the issues presented by classifying these under current classification criteria, and discusses the possibility of a comprehensive and consistent characteristics-based classification framework based on new waste streams created from advanced fuel cycles. A static mass flow model, Fuel-Cycle Integration and Tradeoffs (FIT), was used to calculate the composition of waste streams resulting from different nuclear fuel cycle choices. Because heat generation is generally the most important factor limiting geological repository areal loading, this analysis focuses on the impact of waste form heat load on waste classification practices, although classifying by metrics of radiotoxicity, mass, and volume is also possible. Waste streams generated in different fuel cycles and their possible classification based on the current U.S. framework and international standards are discussed. It is shown that the effects of separating waste streams are neglected under a source-based radioactive waste classification system. (authors)

  13. Analytical Investigation of Cycle Characteristics for Advanced Turboelectric Space Power Systems

    NASA Technical Reports Server (NTRS)

    Moffitt, Thomas P.; Klag, Frederick W.

    1960-01-01

    An investigation was made of the relative influence of turbine inlet temperature, radiator temperature, and turbine efficiency on radiator area for Rankine cycles with rubidium, potassium, and sodium as working fluids. It was determined that, whereas turbine inlet temperature and turbine efficiency have gross effects on radiator size for a given inlet temperature a considerable latitude in the selection of radiator temperature may be accepted with only minor effects on required radiator size. Also investigated was the influence on turbine efficiency and design of the factors that distinguish alkali-metal vapor turbines from conventional gas turbines. The turbine configuration was determined to be a function of the involved working fluids and rotor blade speed. For a given blade speed, the number of stages required for high turbine efficiency was found to vary directly with turbine specific work output, and therefore to vary in the ratio 5 to 2.5 to 1 for sodium, potassium, and rubidium, respectively. Lower blade speeds than employed in conventional gas turbines may be required to satisfy critical stress considerations resulting from the elevated temperatures involved and the criterion of long-duration reliability. This will increase the number of turbine stages necessary to obtain high turbine efficiency and consequently increase turbine weight. The question of moisture formation was discussed and a calculation was made to indicate the nature of the aerodynamic losses due to moisture content. Various means of reducing moisture content were considered, including mechanical removal, increased radiator temperature, inefficient expansion, superheat, and reheat. Sample calculations were made in most cases to indicate their comparative effectiveness and resultant penalty in required radiator area.

  14. Development and Utilization of mathematical Optimization in Advanced Fuel Cycle Systems Analysis

    SciTech Connect

    Turinsky, Paul; Hays, Ross

    2011-09-02

    Over the past sixty years, a wide variety of nuclear power technologies have been theorized, investigated and tested to various degrees. These technologies, if properly applied, could provide a stable, long-term, economical source of CO2-free electric power. However, the recycling of nuclear fuel introduces a degree of coupling between reactor systems which must be accounted for when making long term strategic plans. This work investigates the use of a simulated annealing optimization algorithm coupled together with the VISION fuel cycle simulation model in order to identify attractive strategies from economic, evironmental, non-proliferation and waste-disposal perspectives, which each have associated an objective function. The simulated annealing optimization algorithm works by perturbing the fraction of new reactor capacity allocated to each available reactor type (using a set of heuristic rules) then evaluating the resulting deployment scenario outcomes using the VISION model and the chosen objective functions. These new scenarios, which are either accepted or rejected according the the Metropolis Criterion, are then used as the basis for further perturbations. By repeating this process several thousand times, a family of near-optimal solutions are obtained. Preliminary results from this work using a two-step, Once-through LWR to Full-recycle/FRburner deployment scenario with exponentially increasing electric demand indicate that the algorithm is capable of nding reactor deployment pro les that reduce the long-term-heat waste disposal burden relative to an initial reference scenario. Further work is under way to re ne the current results and to extend them to include the other objective functions and to examine the optimization trade-o s that exist between these di erent objectives.

  15. Seismic Stratigraphy of Ice Sheet Advance-Retreat Cycles on the Sabrina Coast Continental Shelf, East Antarctica

    NASA Astrophysics Data System (ADS)

    Frederick, B. C.; Gulick, S. P. S.; Saustrup, S.; Fernandez-Vasquez, R. A.; Domack, E. W.; Lavoie, C.; Blankenship, D. D.; Leventer, A.; Shevenell, A.

    2014-12-01

    2D multichannel seismic (MCS), multibeam and CHIRP data were collected as part of the recent R/V Nathaniel B. Palmer (NBP1402) cruise to investigate the marine record of cryosphere-ocean dynamics on the continental shelf between the Dalton Ice Tongue and Totten Glacier systems. Outlet glaciers and ice shelves along this coastline drain a catchment area extending across the Aurora Subglacial Basin (ASB) whose topography lies below sea level and contains an ice volume of approximately 6.9m of sea level rise equivalent. Analysis of over 750km of high-resolution MCS data has revealed the preservation of extensive tilted fluvial-deltaic shelf sedimentation and the first evidence of polythermal glacial advance in this region with well-preserved subglacial meltwater channels and tunnel valley systems. This expansive fluvial to glacial sedimentary section is separated by a regional unconformity from a series of irregular, localized unconformities preserved in an otherwise seismically transparent facies. We interpret these transparent facies as subglacial diamictites deposited over several glacial cycles. Detailed seismic stratigraphic analysis of the glacial sequences above the regional unconformity identified at least 4 glacial cycles illustrated by grounding zone wedge moraine deposits recorded in both MCS and multibeam bathymetric data. Distinct differences were evident in the stratigraphic architecture of polar versus polythermal glaciations including greater preservation of till deposits above the regional unconformity proximal to the exposed bedrock boundary and the present-day ice front. Sedimentary sequence preservation here appears dictated by the geometry of local ice advance and allied basement structure controls. Integration of marine geology, high resolution CHIRP and multibeam bathymetry data with MCS sequence geometry and acoustic facies mapping has led to improved constraints on rates, styles and patterns of glacial retreat. Such improvements to deformable

  16. Advanced Camera for Surveys Instrument Handbook for Cycle 21 v. 12.0

    NASA Astrophysics Data System (ADS)

    Ubeda, L.; et al.

    2012-12-01

    The Advanced Camera for Surveys (ACS), a third-generation instrument, was installed in the Hubble Space Telescope during Servicing Mission 3B, on March 7, 2002 (http://www.stsci.edu/hst/HST_overview/servicing_missions). Its primary purpose was to increase HST imaging discovery efficiency by about a factor of 10, with a combination of detector area and quantum efficiency that surpasses previous instruments. ACS has three independent cameras that have provided wide-field, high resolution, and ultraviolet imaging capabilities respectively, using a broad assortment of filters designed to address a large range of scientific goals. In addition, coronagraphic, polarimetric, and grism capabilities have made the ACS a versatile and powerful instrument. The ACS Instrument Handbook, which is maintained by the ACS/WFPC2 Team at STScI, describes the instrument properties, performance, operations, and calibration. It is the basic technical reference manual for the instrument, and should be used with other documents (listed in Table 1.1) for writing Phase I proposals, detailed Phase II programs, and for data analysis. (See Figure 1.1). In May 2009, Servicing Mission 4 (SM4) successfully restored the ACS Wide Field Camera (WFC) to regular service after its failure in January 2007. Unfortunately, the ACS High Resolution Camera (HRC) was not restored to operation during SM4, so it cannot be proposed for new observations. Nevertheless, this handbook retains description of the HRC to support analysis of archived observations. The ACS Solar Blind Channel (SBC) was unaffected by the January 2007 failure of WFC and HRC. The SBC has remained in steady operation, and was not serviced during SM4. It remains available for new observations.

  17. Thermal and hydrodynamic variability within a gravel bar of an Alpine stream and its link to hyporheic carbon cycling

    NASA Astrophysics Data System (ADS)

    Boodoo, Kyle; Schelker, Jakob; Fasching, Christina; Ulseth, Amber; Battin, Tom

    2015-04-01

    In-stream bodies of fluvial sediment such as gravel bars (GB), form an active interface between streamwater and the adjacent groundwater body. The hydrodynamic exchange, that is, the varying contributions of different water sources to this mixing zone, control the GB physical and biogeochemical conditions, including water temperature, as well as nutrient and carbon availability, likely impacting carbon turnover. We present high frequency data for hydraulic head and water temperature in addition to event based measurements of electric conductivity, nutrients and dissolved organic carbon (DOC) concentration and composition within a GB of an Alpine cold water stream (Oberer Seebach, Austria) for a range of different flow conditions. The highest vertical temperature differences and hydraulic head variability occurred at the head and shoulder - largest raised area perpendicular to surface water flow (downwelling) and tail (upwelling) of the gravel bar. At baseflow, high spatial variability of temperature (up to 4° C difference among sites within the same horizontal plane) and hydraulic head was observed within the GB. In contrast, floods resulted in markedly lower overall hyporheic zone temperatures (average 2° C difference among sites within the same horizontal plane) and spatial hydraulic head variability, compared to baseflow conditions. Similarly, the relative difference between surface water and GB nutrient and DOC concentrations and the overall spatial variability within the GB decreased with increasing surface water discharge. For example, at baseflow surface water average DOC and nitrate (NO3) concentrations were 1.40 mgL-1and 810 μgL-1respectively, and 1.97 mgL-1 and 779 μgL-1 respectively at intermediate flow. Meanwhile, DOC and NO3 concentrations in the GB ranged from 1.40 - 3.60 mgL-1 and 150 - 950 μgL-1respectively during baseflow and 1.48 -2.25 mgL-1 and 560 -840 μgL-1 respectively during moderate flows. Furthermore, DOC and NH4 concentrations

  18. Power fade and capacity fade resulting from cycle-life testing of Advanced Technology Development Program lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Wright, R. B.; Christophersen, J. P.; Motloch, C. G.; Belt, J. R.; Ho, C. D.; Battaglia, V. S.; Barnes, J. A.; Duong, T. Q.; Sutula, R. A.

    This paper presents the test results and analysis of the power and capacity fade resulting from the cycle-life testing using PNGV (now referred to as FreedomCAR) test protocols at 25 and 45 °C of 18650-size Li-ion batteries developed by the US Department of Energy sponsored Advanced Technology Development (ATD) Program. Two cell chemistries were studied, a Baseline chemistry that had a cathode composition of LiNi 0.8Co 0.15Al 0.05O 2 with binders, that was cycle-life tested at 25 and 45 °C, and a Variant C chemistry with a cathode composition of LiNi 0.8Co 0.10Al 0.10O 2 with binders, that was tested only at 45 °C. The 300 Wh power, and % power fade were determined as a function of test time, i.e. the number of test cycles for up to 44 weeks (369,600 test cycles) for the Baseline cells, and for 24 weeks (201,600 test cycles) for the Variant C cells. The C/1 and C/25 discharge capacity and capacity fade were also determined during the course of these studies. The results of this study indicate that the 300 Wh power for the Baseline cells tested at 25 °C (up to 44 weeks of testing) decreased as a linear function of test time. The % power fade for these cells increased as a linear function of test time. The Baseline cells tested at 45 °C (up to 44 weeks of testing) displayed a decrease in their power proportional to the square root of the test time, with a faster rate of decrease of the power occurring at ˜28 weeks of testing. The % power fade for these cells also increased as the square root of the test time, and exhibited an increase in the % power fade rate at ˜28 weeks of testing. The 45 °C tested Baseline cells' power decreased, and their % power fade increased at a greater rate than the 25 °C tested Baseline cells. The power fade was greater for the Variant C cells. The power of the Variant C cells (tested at 45 °C) decreased as the square root of the test time, and their % power fade was also found to be a function of the square root of the test time

  19. Guidelines for Reporting Articles on Psychiatry and Heart rate variability (GRAPH): recommendations to advance research communication.

    PubMed

    Quintana, D S; Alvares, G A; Heathers, J A J

    2016-01-01

    The number of publications investigating heart rate variability (HRV) in psychiatry and the behavioral sciences has increased markedly in the last decade. In addition to the significant debates surrounding ideal methods to collect and interpret measures of HRV, standardized reporting of methodology in this field is lacking. Commonly cited recommendations were designed well before recent calls to improve research communication and reproducibility across disciplines. In an effort to standardize reporting, we propose the Guidelines for Reporting Articles on Psychiatry and Heart rate variability (GRAPH), a checklist with four domains: participant selection, interbeat interval collection, data preparation and HRV calculation. This paper provides an overview of these four domains and why their standardized reporting is necessary to suitably evaluate HRV research in psychiatry and related disciplines. Adherence to these communication guidelines will help expedite the translation of HRV research into a potential psychiatric biomarker by improving interpretation, reproducibility and future meta-analyses. PMID:27163204

  20. Evaluation of terrestrial carbon cycle models for their response to climate variability and to CO2 trends.

    PubMed

    Piao, Shilong; Sitch, Stephen; Ciais, Philippe; Friedlingstein, Pierre; Peylin, Philippe; Wang, Xuhui; Ahlström, Anders; Anav, Alessandro; Canadell, Josep G; Cong, Nan; Huntingford, Chris; Jung, Martin; Levis, Sam; Levy, Peter E; Li, Junsheng; Lin, Xin; Lomas, Mark R; Lu, Meng; Luo, Yiqi; Ma, Yuecun; Myneni, Ranga B; Poulter, Ben; Sun, Zhenzhong; Wang, Tao; Viovy, Nicolas; Zaehle, Soenke; Zeng, Ning

    2013-07-01

    The purpose of this study was to evaluate 10 process-based terrestrial biosphere models that were used for the IPCC fifth Assessment Report. The simulated gross primary productivity (GPP) is compared with flux-tower-based estimates by Jung et al. [Journal of Geophysical Research 116 (2011) G00J07] (JU11). The net primary productivity (NPP) apparent sensitivity to climate variability and atmospheric CO2 trends is diagnosed from each model output, using statistical functions. The temperature sensitivity is compared against ecosystem field warming experiments results. The CO2 sensitivity of NPP is compared to the results from four Free-Air CO2 Enrichment (FACE) experiments. The simulated global net biome productivity (NBP) is compared with the residual land sink (RLS) of the global carbon budget from Friedlingstein et al. [Nature Geoscience 3 (2010) 811] (FR10). We found that models produce a higher GPP (133 ± 15 Pg C yr(-1) ) than JU11 (118 ± 6 Pg C yr(-1) ). In response to rising atmospheric CO2 concentration, modeled NPP increases on average by 16% (5-20%) per 100 ppm, a slightly larger apparent sensitivity of NPP to CO2 than that measured at the FACE experiment locations (13% per 100 ppm). Global NBP differs markedly among individual models, although the mean value of 2.0 ± 0.8 Pg C yr(-1) is remarkably close to the mean value of RLS (2.1 ± 1.2 Pg C yr(-1) ). The interannual variability in modeled NBP is significantly correlated with that of RLS for the period 1980-2009. Both model-to-model and interannual variation in model GPP is larger than that in model NBP due to the strong coupling causing a positive correlation between ecosystem respiration and GPP in the model. The average linear regression slope of global NBP vs. temperature across the 10 models is -3.0 ± 1.5 Pg C yr(-1) °C(-1) , within the uncertainty of what derived from RLS (-3.9 ± 1.1 Pg C yr(-1) °C(-1) ). However, 9 of 10 models overestimate the regression slope of NBP vs. precipitation

  1. Does thermal variability experienced at the egg stage influence life history traits across life cycle stages in a small invertebrate?

    PubMed

    Xing, Kun; Hoffmann, Ary A; Ma, Chun-Sen

    2014-01-01

    Although effects of thermal stability on eggs have often been considered in vertebrates, there is little data thermal stability in insect eggs even though these eggs are often exposed in nature to widely fluctuating ambient conditions. The modularity of development in invertebrates might lead to compensation across life cycle stages but this remains to be tested particularly within the context of realistic temperature fluctuations encountered in nature. We simulated natural temperate fluctuations on eggs of the worldwide cruciferous insect pest, the diamondback moth (DBM), Plutella xylostella (L.), while maintaining the same mean temperature (25°C±0°C, 25±4°C, 25±6°C, 25±8°C, 25±10°C, 25±12°C) and assessed egg development, survival and life history traits across developmental stages. Moderate fluctuations (25±4°C, 25±6°C) did not influence performance compared to the constant temperature treatment, and none of the treatments influenced egg survival. However the wide fluctuating temperatures (25±10°C, 25±12°C) slowed development time and led to an increase in pre-pupal mass, although these changes did not translate into any effects on longevity or fecundity at the adult stage. These findings indicate that environmental effects can extend across developmental stages despite the modularity of moth development but also highlight that there are few fitness consequences of the most variable thermal conditions likely to be experienced by Plutella xylostella. PMID:24911213

  2. Efficiency optimization of a closed indirectly fired gas turbine cycle working under two variable-temperature heat reservoirs

    NASA Astrophysics Data System (ADS)

    Ma, Zheshu; Wu, Jieer

    2011-08-01

    Indirectly or externally fired gas turbines (IFGT or EFGT) are interesting technologies under development for small and medium scale combined heat and power (CHP) supplies in combination with micro gas turbine technologies. The emphasis is primarily on the utilization of the waste heat from the turbine in a recuperative process and the possibility of burning biomass even "dirty" fuel by employing a high temperature heat exchanger (HTHE) to avoid the combustion gases passing through the turbine. In this paper, finite time thermodynamics is employed in the performance analysis of a class of irreversible closed IFGT cycles coupled to variable temperature heat reservoirs. Based on the derived analytical formulae for the dimensionless power output and efficiency, the efficiency optimization is performed in two aspects. The first is to search the optimum heat conductance distribution corresponding to the efficiency optimization among the hot- and cold-side of the heat reservoirs and the high temperature heat exchangers for a fixed total heat exchanger inventory. The second is to search the optimum thermal capacitance rate matching corresponding to the maximum efficiency between the working fluid and the high-temperature heat reservoir for a fixed ratio of the thermal capacitance rates of the two heat reservoirs. The influences of some design parameters on the optimum heat conductance distribution, the optimum thermal capacitance rate matching and the maximum power output, which include the inlet temperature ratio of the two heat reservoirs, the efficiencies of the compressor and the gas turbine, and the total pressure recovery coefficient, are provided by numerical examples. The power plant configuration under optimized operation condition leads to a smaller size, including the compressor, turbine, two heat reservoirs and the HTHE.

  3. Radioactive waste partitioning and transmutation within advanced fuel cycles: Achievements and Challenges

    SciTech Connect

    M. Salvatores; G. Palmiotti

    2011-01-01

    to be loaded with fuels with potentially very different mixtures of Pu and minor actinides (MA), according to the chosen approach and the objective of the P&T strategy, and this without affecting its safety or penalizing its operability. A major issue of any P&T implementation strategy is a detailed evaluation of the impact of each strategy on the different features and installations of the fuel cycle, and a discussion of this issue will be provided in chapter 6. Chapter 7 will tackle the problem of nuclear data uncertainties and their impact on the nominal performances of the different transmutation systems. Finally, in chapter 8 it will be discussed in more detail the role of the different types of fast reactors described in the previous chapters, according to the different P&T objectives and implementation scenarios.

  4. The Potential of the MAGIC TOM Parental Accessions to Explore the Genetic Variability in Tomato Acclimation to Repeated Cycles of Water Deficit and Recovery.

    PubMed

    Ripoll, Julie; Urban, Laurent; Bertin, Nadia

    2015-01-01

    Episodes of water deficit (WD) during the crop cycle of tomato may negatively impact plant growth and fruit yield, but they may also improve fruit quality. Moreover, a moderate WD may induce a plant "memory effect" which is known to stimulate plant acclimation and defenses for upcoming stress episodes. The objective of this study was to analyze the positive and negative impacts of repeated episodes of WD at the plant and fruit levels. Three episodes of WD (-38, -45, and -55% of water supply) followed by three periods of recovery ("WD treatments"), were applied to the eight parents of the Multi-Parent Advanced Generation Inter-Cross population which offers the largest allelic variability observed in tomato. Predawn and midday water potentials, chlorophyll a fluorescence, growth and fruit quality traits [contents in sugars, acids, carotenoids, and ascorbic acid (AsA)] were measured throughout the experiment. Important genotypic variations were observed both at the plant and fruit levels and variations in fruit and leaf traits were found not to be correlated. Overall, the WD treatments were at the origin of important osmotic regulations, reduction of leaf growth, acclimation of photosynthetic functioning, notably through an increase in the chlorophyll content and in the quantum yield of the electron transport flux until PSI acceptors (J 0 (RE1)/J (ABS)). The effects on fruit sugar, acid, carotenoid and AsA contents on a dry matter basis ranged from negative to positive to nil depending on genotypes and stress intensity. Three small fruit size accessions were richer in AsA on a fresh matter basis, due to concentration effects. So, fruit quality was improved under WD mainly through concentration effects. On the whole, two accessions, LA1420 and Criollo appeared as interesting genetic resources, cumulating adaptive traits both at the leaf and fruit levels. Our observations show that the complexity involved in plant responses, when considering a broad range of

  5. The Potential of the MAGIC TOM Parental Accessions to Explore the Genetic Variability in Tomato Acclimation to Repeated Cycles of Water Deficit and Recovery

    PubMed Central

    Ripoll, Julie; Urban, Laurent; Bertin, Nadia

    2016-01-01

    Episodes of water deficit (WD) during the crop cycle of tomato may negatively impact plant growth and fruit yield, but they may also improve fruit quality. Moreover, a moderate WD may induce a plant “memory effect” which is known to stimulate plant acclimation and defenses for upcoming stress episodes. The objective of this study was to analyze the positive and negative impacts of repeated episodes of WD at the plant and fruit levels. Three episodes of WD (–38, –45, and –55% of water supply) followed by three periods of recovery (“WD treatments”), were applied to the eight parents of the Multi-Parent Advanced Generation Inter-Cross population which offers the largest allelic variability observed in tomato. Predawn and midday water potentials, chlorophyll a fluorescence, growth and fruit quality traits [contents in sugars, acids, carotenoids, and ascorbic acid (AsA)] were measured throughout the experiment. Important genotypic variations were observed both at the plant and fruit levels and variations in fruit and leaf traits were found not to be correlated. Overall, the WD treatments were at the origin of important osmotic regulations, reduction of leaf growth, acclimation of photosynthetic functioning, notably through an increase in the chlorophyll content and in the quantum yield of the electron transport flux until PSI acceptors (J0RE1/JABS). The effects on fruit sugar, acid, carotenoid and AsA contents on a dry matter basis ranged from negative to positive to nil depending on genotypes and stress intensity. Three small fruit size accessions were richer in AsA on a fresh matter basis, due to concentration effects. So, fruit quality was improved under WD mainly through concentration effects. On the whole, two accessions, LA1420 and Criollo appeared as interesting genetic resources, cumulating adaptive traits both at the leaf and fruit levels. Our observations show that the complexity involved in plant responses, when considering a broad range of

  6. The Climate Variability & Predictability (CVP) Program at NOAA - DYNAMO Recent Project Advancements

    NASA Astrophysics Data System (ADS)

    Lucas, S. E.; Todd, J. F.; Higgins, W.

    2013-12-01

    The Climate Variability & Predictability (CVP) Program supports research aimed at providing process-level understanding of the climate system through observation, modeling, analysis, and field studies. This vital knowledge is needed to improve climate models and predictions so that scientists can better anticipate the impacts of future climate variability and change. To achieve its mission, the CVP Program supports research carried out at NOAA and other federal laboratories, NOAA Cooperative Institutes, and academic institutions. The Program also coordinates its sponsored projects with major national and international scientific bodies including the World Climate Research Programme (WCRP), the International Geosphere-Biosphere Programme (IGBP), and the U.S. Global Change Research Program (USGCRP). The CVP program sits within the Earth System Science (ESS) Division at NOAA's Climate Program Office. Dynamics of the Madden-Julian Oscillation (DYNAMO): The Indian Ocean is one of Earth's most sensitive regions because the interactions between ocean and atmosphere there have a discernable effect on global climate patterns. The tropical weather that brews in that region can move eastward along the equator and reverberate around the globe, shaping weather and climate in far-off places. The vehicle for this variability is a phenomenon called the Madden-Julian Oscillation, or MJO. The MJO, which originates over the Indian Ocean roughly every 30 to 90 days, is known to influence the Asian and Australian monsoons. It can also enhance hurricane activity in the northeast Pacific and Gulf of Mexico, trigger torrential rainfall along the west coast of North America, and affect the onset of El Niño. CVP-funded scientists participated in the DYNAMO field campaign in 2011-12. Results from this international campaign are expected to improve researcher's insights into this influential phenomenon. A better understanding of the processes governing MJO is an essential step toward

  7. Economic Analyiss of "Symbiotic" Light Water Reactor/Fast Burner Reactor Fuel Cycles Proposed as Part of the U.S. Advanced Fuel Cycle Initiative (AFCI)

    SciTech Connect

    Williams, Kent Alan; Shropshire, David E.

    2009-01-01

    A spreadsheet-based 'static equilibrium' economic analysis was performed for three nuclear fuel cycle scenarios, each designed for 100 GWe-years of electrical generation annually: (1) a 'once-through' fuel cycle based on 100% LWRs fueled by standard UO2 fuel assemblies with all used fuel destined for geologic repository emplacement, (2) a 'single-tier recycle' scenario involving multiple fast burner reactors (37% of generation) accepting actinides (Pu,Np,Am,Cm) from the reprocessing of used fuel from the uranium-fueled LWR fleet (63% of generation), and (3) a 'two-tier' 'thermal+fast' recycle scenario where co-extracted U,Pu from the reprocessing of used fuel from the uranium-fueled part of the LWR fleet (66% of generation) is recycled once as full-core LWR MOX fuel (8% of generation), with the LWR MOX used fuel being reprocessed and all actinide products from both UO2 and MOX used fuel reprocessing being introduced into the closed fast burner reactor (26% of generation) fuel cycle. The latter two 'closed' fuel cycles, which involve symbiotic use of both thermal and fast reactors, have the advantages of lower natural uranium requirements per kilowatt-hour generated and less geologic repository space per kilowatt-hour as compared to the 'once-through' cycle. The overall fuel cycle cost in terms of $ per megawatt-hr of generation, however, for the closed cycles is 15% (single tier) to 29% (two-tier) higher than for the once-through cycle, based on 'expected values' from an uncertainty analysis using triangular distributions for the unit costs for each required step of the fuel cycle. (The fuel cycle cost does not include the levelized reactor life cycle costs.) Since fuel cycle costs are a relatively small percentage (10 to 20%) of the overall busbar cost (LUEC or 'levelized unit electricity cost') of nuclear power generation, this fuel cycle cost increase should not have a highly deleterious effect on the competitiveness of nuclear power. If the reactor life cycle

  8. Impact of the ocean diurnal cycle on the intraseasonnal variability of Sea Surface Temperatures in the mid-latitudes Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Guemas, V.; Salas-Mélia, D.; Kageyama, M.; Giordani, H.; Voldoire, A.

    2009-04-01

    Some recent studies have shown that the ocean diurnal cycle could increase the intraseasonal variability of the Sea Surface Temperatures (SST) in the tropics (Shinoda and Hendon, 1998; Bernie et al, 2005; Shinoda, 2005). This study aims at extending these analyses to the mid-latitudes. To conduct these analyses, the CNRMOM1D 1-dimensional ocean model is forced with ERA40 reanalysis data with a 1 hour frequency in solar heat flux ( 6h hours for the other forcing fields ). The turbulent vertical mixing scheme (Gaspar et al., 1988) is based on the parameterisation of the second-order turbulent moments expressed as a function of the turbulent kinetic energy. The model has 124 vertical levels with a vertical resolution of 1m near the surface and 500m at the bottom. This high vertical resolution combined with a high temporal forcing resolution allows to simulate a realistic diurnal cycle of the oceanic upper-layers. This experiment is compared with one forced on a daily time-step. By comparing both experiments, the impact of the ocean diurnal cycle on the intraseasonnal variability of sea surface temperature anomalies is assessed. We show that the phase of the SST variability is affected and this impact is strongly associated with the non-linear interactions between the diurnal cycle in mixed layer depth and surface forcings.

  9. A Damage Model for the Simulation of Delamination in Advanced Composites under Variable-Mode Loading

    NASA Technical Reports Server (NTRS)

    Turon, A.; Camanho, P. P.; Costa, J.; Davila, C. G.

    2006-01-01

    A thermodynamically consistent damage model is proposed for the simulation of progressive delamination in composite materials under variable-mode ratio. The model is formulated in the context of Damage Mechanics. A novel constitutive equation is developed to model the initiation and propagation of delamination. A delamination initiation criterion is proposed to assure that the formulation can account for changes in the loading mode in a thermodynamically consistent way. The formulation accounts for crack closure effects to avoid interfacial penetration of two adjacent layers after complete decohesion. The model is implemented in a finite element formulation, and the numerical predictions are compared with experimental results obtained in both composite test specimens and structural components.

  10. Subsurface N cycling under variable paddy flood management: what role does it play in N2O emissions?

    NASA Astrophysics Data System (ADS)

    Verhoeven, Elizabeth; Pierreux, Sofie; Decock, Charlotte; Romani, Marco; Sleutel, Steven; Six, Johan

    2016-04-01

    There is increasing pressure to grow rice with less water in order to save water and mitigate methane (CH4) emissions. However, there is frequently a trade-off with yield declines and increased nitrous oxide (N2O) emissions, potentially increasing the global warming potential of the system. A field trial in Northern Italy was established with two water regimes: continuously flooded (flooded) and alternate wetting and drying (AWD), to investigate the impact of such water management on N2O emissions and N cycling along a depth profile. Surface gas fluxes were complimented by depth profile measurements of soil gas, inorganic N, DOC, dissolved gas concentrations, redox potential and moisture. Sampling was concentrated around two periods during the 2015 growing season which were hypothesized to show significant variation in N dynamics; a fertilization event and final season drainage. For N cycling and N2O emissions, stable isotope measurements were taken to obtain process-level information in situ. During the first field campaign, maximum mean daily N2O emissions did not peak at fertilization but rather a week earlier, demonstrating a greater response to soil conditions (i.e. higher redox and lower moisture) than inorganic N concentrations. This was especially the case in the AWD treatment where emissions peaked at 82.3 ± 126.0 g N2O-N ha-1 d-1 relative to a peak of 2.83 ± 1.1 g N2O-N ha-1 d-1 in the flooded treatment. Considering the upper depths (0-15 cm), peak emissions corresponded well to higher redox potentials in the AWD treatment (72-406 mV versus -100 to -12 mV for AWD and flooded treatments, respectively). These emissions also correlated well to pore space N2O concentrations at 5 and 12.5 cm, suggesting important production of N2O at these depths and subsequent diffusion to the soil surface. Pore space and dissolved N2O concentrations were much lower in the flooded treatment and no such spikes were observed. No significant N2O emissions were observed in

  11. Trophic ecology of Lampanyctus crocodilus on north-west Mediterranean Sea slopes in relation to reproductive cycle and environmental variables.

    PubMed

    Fanelli, E; Papiol, V; Cartes, J E; Rodriguez-Romeu, O

    2014-06-01

    This study examined the population structure, reproductive cycle and feeding pattern of the lanternfish Lampanyctus crocodilus in the Balearic Basin (north-west Mediterranean Sea) from a depth of 450 to 1800 m and at a seasonal scale. Juveniles were mainly located at shallower depths, but also at deepest stations in autumn, while adults mostly inhabited intermediate depths with their centre of population density (CPD) located at 800-1000 m of depth. The migration of adults to deeper depths was detected in late summer to autumn, probably linked to the occurrence of nepheloid layers at c. 1200 m, which in turn enhances the biomass of the zooplankton prey. The diet was mainly based on euphausiids and mysids, with marked seasonal variations both on the upper (450-800 m) and lower (1000-1800 m), where suprabenthic gammariids and pelagic decapods were also dominant. Stomach fullness increased from winter to autumn on the US, while it had a maximum in spring on the LS, in parallel with high consumption of gelatinous zooplankton, which is probably more available after the phytoplankton bloom in late winter. Reproduction occurred in winter, confirmed by the higher percentage of mature females and high gonadosomatic indices (I(G)) at both depth ranges. Hepatosomatic indices (I(H)) showed an inverse trend to I(G) on the US, except in autumn, and was almost parallel on the LS, probably attributable to the migration of adults, which determined different temporal schemes in energy use and storage for reproduction on the US v. LS. Consistent with the different patterns observed at the two depth ranges, environmental drivers of fullness (i.e. feeding intensity) and I(G) (as a proxy of reproductive cycle) differed on the US and LS. The biomass of mysids and euphausiids was the greatest explanatory variables of fullness on the US and LS, pointing to the increasing feeding intensity when a resource was more available. I(H) also explained fullness, suggesting that greater

  12. [Variability of the duration of the cell cycle in pig embryo kidney cells in monolayer culture and correlation of the cycle duration in sister cells].

    PubMed

    Blokhin, A V; Voronkova, L N; Sakharov, V N

    1985-07-01

    The distribution of generation time of sister cells for the exponentially proliferating monolayer SPEV culture was obtained with time lapse cinemicrographic technique. The distribution is characterized by the average generation time equal to 24.3 hour, with the variation coefficient, asymmetry coefficient and correlation coefficient for sister pair cell being, respectively, 17%, 0.2 and 0.78. The results obtained are compared with the prediction of "a random transition" in the cell cycle. PMID:3901449

  13. Effect of LEO cycling on 125 Ah advanced design IPV nickel-hydrogen flight cells - An update

    NASA Technical Reports Server (NTRS)

    Smithrick, John J.; Hall, Stephen W.

    1991-01-01

    An update of validation test results confirming the breakthrough in LEO cycle life of nickel-hydrogen cells containing 26 percent potassium hydroxide (KOH) electrolyte is presented. A breakthrough in the LEO cycle life of individual pressure vessel nickel-hydrogen cells is reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40,000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH.

  14. Processes driving sea ice variability in the Bering Sea in an eddying ocean/sea ice model: Mean seasonal cycle

    NASA Astrophysics Data System (ADS)

    Li, Linghan; McClean, Julie L.; Miller, Arthur J.; Eisenman, Ian; Hendershott, Myrl C.; Papadopoulos, Caroline A.

    2014-12-01

    The seasonal cycle of sea ice variability in the Bering Sea, together with the thermodynamic and dynamic processes that control it, are examined in a fine resolution (1/10°) global coupled ocean/sea-ice model configured in the Community Earth System Model (CESM) framework. The ocean/sea-ice model consists of the Los Alamos National Laboratory Parallel Ocean Program (POP) and the Los Alamos Sea Ice Model (CICE). The model was forced with time-varying reanalysis atmospheric forcing for the time period 1970-1989. This study focuses on the time period 1980-1989. The simulated seasonal-mean fields of sea ice concentration strongly resemble satellite-derived observations, as quantified by root-mean-square errors and pattern correlation coefficients. The sea ice energy budget reveals that the seasonal thermodynamic ice volume changes are dominated by the surface energy flux between the atmosphere and the ice in the northern region and by heat flux from the ocean to the ice along the southern ice edge, especially on the western side. The sea ice force balance analysis shows that sea ice motion is largely associated with wind stress. The force due to divergence of the internal ice stress tensor is large near the land boundaries in the north, and it is small in the central and southern ice-covered region. During winter, which dominates the annual mean, it is found that the simulated sea ice was mainly formed in the northern Bering Sea, with the maximum ice growth rate occurring along the coast due to cold air from northerly winds and ice motion away from the coast. South of St Lawrence Island, winds drive the model sea ice southwestward from the north to the southwestern part of the ice-covered region. Along the ice edge in the western Bering Sea, model sea ice is melted by warm ocean water, which is carried by the simulated Bering Slope Current flowing to the northwest, resulting in the S-shaped asymmetric ice edge. In spring and fall, similar thermodynamic and dynamic

  15. Carbonate and lignite cycles in the Ptolemais Basin: Orbital control and suborbital variability (Late Neogene, northern Greece)

    NASA Astrophysics Data System (ADS)

    Weber, M. E.; Tougiannidis, N.; Ricken, W.; Rolf, C.; Kleineder, M.; Bertram, N.; Antoniadis, P.

    2009-04-01

    We recently commenced a project to investigate deep drillings as well as outcrops in the Ptolemais Basin, northern Greece, for paleoenvironmental and paleoclimate change. Specific attention is paid to mining sites Achlada, Vevi, Vegora, Amynteon, North Field, South Field, and Lava. The sediment archive comprises Upper Miocene to Quaternary continental lake deposits (up to 800 m thick) with an extended Lower Pliocene section. The Upper Miocene sections are composed of diatomaceous mud and gray marls. Pliocene lake sediments commence with the Kyrio member (lignite/grey marl), followed by the Theodoxus member (beige marl/lignite), and the Notio member (marl with intercalated sand /lignite). The limnic deposits show striking rhythmic bedding of (mostly) carbonates and lignites, reflecting orbital-induced humidity and temperature changes in this small NW-SE elongated continental basin. First, we retrieved chronometric information by determining magnetic polarity changes on three sites as independent stratigraphic ground-truth in combination with palynological evidence and published data. Then we conducted a number of high-resolution (1 - 6 cm increment), non-destructive measurements to obtain paleoclimate proxies: photospectrometry (colors L, a, b), magnetic susceptibility, and natural gamma. Accordingly, we achieved a multi-proxy insight into paleoclimate and paleoenvironmental evolution at unprecedented temporal resolution (up to a few decades!) over long time series and at a number of key sites. Using the newly-developed ESALab software, we conducted spectral and evolutionary spectral analysis to evaluate the cyclo-stratigraphic development. As for orbital variability, spectral power is concentrated on precession, hemi-precession, and eccentricity, with only minor impact of orbital tilt. We used this information to increase the temporal resolution of our age models by tuning as many precession (insolation) maxima as possible to carbonate minima (lignite maxima

  16. Advanced Control of Permanent Magnet Synchronous Generators for Variable Speed Wind Energy Conversion Systems

    NASA Astrophysics Data System (ADS)

    Hostettler, Jacob

    Various environmental and economic factors have lead to increased global investment in alternative energy technologies such as solar and wind power. Although methodologies for synchronous generator control are well researched, wind turbines present control systems challenges not presented by traditional generation. The varying nature of wind makes achieving synchronism with the existing electrical power grid a greater challenge. Departing from early use of induction machines, permanent magnet synchronous generators have become the focus of power systems and control systems research into wind energy systems. This is due to their self excited nature, along with their high power density. The problem of grid synchronism is alleviated through the use of high performance power electronic converters. In achievement of the optimal levels of efficiency, advanced control systems techniques oer promise over more traditional approaches. Research into sliding mode control, and linear matrix inequalities with nite time boundedness and Hinfinity performance criteria, when applied to the dynamical models of the system, demonstrate the potential of these control methodologies as future avenues for achieving higher levels of performance and eciency in wind energy.

  17. Impact of the modulated annual cycle and intraseasonal oscillation on daily-to-interannual rainfall variability across monsoonal India

    NASA Astrophysics Data System (ADS)

    Moron, Vincent; Robertson, Andrew W.; Ghil, Michael

    2012-06-01

    Variability of the Indian summer monsoon is decomposed into an interannually modulated annual cycle (MAC) and a northward-propagating, intraseasonal (30-60-day) oscillation (ISO). To achieve this decomposition, we apply multi-channel singular spectrum analysis (M-SSA) simultaneously to unfiltered daily fields of observed outgoing long-wave radiation (OLR) and to reanalyzed 925-hPa winds over the Indian region, from 1975 to 2008. The MAC is essentially given by the year-to-year changes in the annual and semi-annual components; it displays a slow northward migration of OLR anomalies coupled with an alternation between the northeast winter and southwest summer monsoons. The impact of these oscillatory modes on rainfall is then analyzed using a 1-degree gridded daily data set, focusing on Monsoonal India (north of 17°N and west of 90°E) during the months of June to September. Daily rainfall variability is partitioned into three states using a Hidden Markov Model. Two of these states are shown to agree well with previous classifications of "active" and "break" phases of the monsoon, while the third state exhibits a dipolar east-west pattern with abundant rainfall east of about 77°E and low rainfall to the west. Occurrence of the three rainfall states is found to be an asymmetric function of both the MAC and ISO components. On average, monsoon active phases are favored by large positive anomalies of MAC, and breaks by negative ones. ISO impact is decisive when the MAC is near neutral values during the onset and withdrawal phases of the monsoon. Active monsoon spells are found to require a synergy between the MAC and ISO, while the east-west rainfall dipole is less sensitive to interactions between the two. The driest years, defined from spatially averaged June-September rainfall anomalies, are found to be mostly a result of breaks occurring during the onset and withdrawal stages of the monsoon, e.g., mid-June to mid-July, and during September. These breaks are in turn

  18. Performance Diagnosis using Optical Torque Sensor for Selection of a Steam Supply Plant among Advanced Combined Cycle Power Plants

    NASA Astrophysics Data System (ADS)

    Umezawa, Shuichi

    A newly developed optical torque sensor was applied to select a steam supply plant among advanced combined cycle, i.e. ACC, power plants of the Tokyo Electric Power Company. The sensor uses laser beams focused on small stainless steel reflectors having bar-code patterns attached on the surface of the rotating shaft, and a technique of signal processing using a correlation function featuring high frequency. The plant that supplied steam was selected on the basis of diagnosis of each steam turbine performance of the plants. Heat balance program was developed to analyze steam turbine performance using data of turbine output measured by the torque sensor and data measured by existing instruments of the power station. The steam turbine that supplied steam was determined by the present method using the optical torque sensor. The accuracy of the method to determine the steam supply plant was analyzed. It was then confirmed that the accuracy was greatly improved as compared with that of existing method.

  19. Realization of the Atkinson-Miller cycle in spark-ignition engine by means of the fully variable inlet valve control system

    NASA Astrophysics Data System (ADS)

    Żmudka, Zbigniew; Postrzednik, Stefan; Przybyła, Grzegorz

    2014-09-01

    The theoretical analysis of the charge exchange process in a spark ignition engine has been presented. This process has significant impact on the effectiveness of engine operation because it is related to the necessity of overcoming the flow resistance, followed by the necessity of doing a work, so-called the charge exchange work. The flow resistance caused by the throttling valve is especially high during the part load operation. The open Atkinson-Miller cycle has been assumed as a model of processes taking place in the engine. Using fully variable inlet valve timing the A-M cycle can be realized according to two systems: system with late inlet valve closing and system with early inlet valve closing. The systems have been analysed individually and comparatively with the open Seiliger-Sabathe cycle which is a theoretical cycle for the classical throttle governing of the engine load. Benefits resulting from application of the systems with independent inlet valve control have been assessed on the basis of the selected parameters: fuel dose, cycle work, charge exchange work and a cycle efficiency. The use of the analysed systems to governing of the SI engine load will enable to eliminate a throttling valve from the system inlet and reduce the charge exchange work, especially within the range of part load operation.

  20. Advances in catchment scale bank erosion modelling - quantifying the improved representation of temporal and spatial variability

    NASA Astrophysics Data System (ADS)

    Janes, Victoria; Holman, Ian; O'Donnell, Greg; Birkinshaw, Stephen; Kilsby, Chris

    2015-04-01

    Channel bank erosion processes are influenced by numerous factors resulting in high spatial and temporal variability of sediment production. The representation of channel bank erosion is overly simplistic within most catchment models, despite its significance to catchment sediment budgets. Within this study, the physically-based distributed SHETRAN model is modified to incorporate bank vegetation and channel sinuosity factors that influence spatial and temporal bank erosion rates. The modified model simulates the temporal variation of bank erosion in response to high magnitude events with the potential to remove bank vegetation and de-stabilise banks, thereby increasing erodibility. As vegetation re-establishes, simulated bank erodibility decreases. During the recovery period, banks have increased vulnerability to further high magnitude events that will result in increased bank erosion. This enables the model to represent the impact of flood clustering on sediment generation. The modified model also represents the spatial variation of bank erosion as a result of varying channel planform. Channel geometry has also been linked to bank erosion rates as a result of flow circulation within channels. Channel sinuosity shows a non-linear relationship with bank erosion, with bank erosion increasing up to a threshold value of sinuosity and decreasing as sinuosity increases above this point. The original and modified models have been applied to the Eden catchment in north east England. Bank erosion data derived from a GIS overlay methodology covering 150 years has been used to validate the models, indicating annual sediment generation from bank erosion processes within the catchment is 410-4500 t yr-1, equivalent to 2-11% of the catchment sediment budget. Comparison of the original and modified models highlights the improved ability of the modified model to simulate annual variation of bank eroded sediment production; annual sediment production from the original model ranged

  1. Advancements in the Quantification of the Crystal Structure of ZNS Materials Produced in Variable Gravity

    NASA Astrophysics Data System (ADS)

    Castillo, Martin

    2016-07-01

    Screens and displays consume tremendous amounts of power. Global trends to significantly consume less power and increase battery life have led to the reinvestigation of electroluminescent materials. The state of the art in ZnS materials has not been furthered in the past 30 years and there is much potential in improving electroluminescent properties of these materials with advanced processing techniques. Self-propagating high temperature synthesis (SHS) utilises a rapid exothermic process involving high energy and nonlinearity coupled with a high cooling rate to produce materials formed outside of normal equilibrium boundaries thus possessing unique properties. The elimination of gravity during this process allows capillary forces to dominate mixing of the reactants which results in a superior and enhanced homogeneity in the product materials. ZnS type materials have been previously conducted in reduced gravity and normal gravity. It has been claimed in literature that a near perfect phases of ZnS wurtzite was produced. Although, the SHS of this material is possible at high pressures, there has been no quantitative information on the actual crystal structures and lattice parameters that were produced in this work. Utilising this process with ZnS doped with Cu, Mn, or rare earth metals such as Eu and Pr leads to electroluminescence properties, thus making this an attractive electroluminescent material. The work described here will revisit the synthesis of ZnS via high pressure SHS and will re-examine the work performed in both normal gravity and in reduced gravity within the ZARM drop tower facility. Quantifications in the lattice parameters, crystal structures, and phases produced will be presented to further explore the unique structure-property performance relationships produced from the SHS of ZnS materials.

  2. Advances in Understanding Top-of-Atmosphere Radiation Variability from Satellite Observations

    NASA Astrophysics Data System (ADS)

    Loeb, Norman G.; Kato, Seiji; Su, Wenying; Wong, Takmeng; Rose, Fred G.; Doelling, David R.; Norris, Joel R.; Huang, Xianglei

    2012-07-01

    This paper highlights how the emerging record of satellite observations from the Earth Observation System (EOS) and A-Train constellation are advancing our ability to more completely document and understand the underlying processes associated with variations in the Earth's top-of-atmosphere (TOA) radiation budget. Large-scale TOA radiation changes during the past decade are observed to be within 0.5 Wm-2 per decade based upon comparisons between Clouds and the Earth's Radiant Energy System (CERES) instruments aboard Terra and Aqua and other instruments. Tropical variations in emitted outgoing longwave (LW) radiation are found to closely track changes in the El Niño-Southern Oscillation (ENSO). During positive ENSO phase (El Niño), outgoing LW radiation increases, and decreases during the negative ENSO phase (La Niña). The coldest year during the last decade occurred in 2008, during which strong La Nina conditions persisted throughout most of the year. Atmospheric Infrared Sounder (AIRS) observations show that the lower temperatures extended throughout much of the troposphere for several months, resulting in a reduction in outgoing LW radiation and an increase in net incoming radiation. At the global scale, outgoing LW flux anomalies are partially compensated for by decreases in midlatitude cloud fraction and cloud height, as observed by Moderate Resolution Imaging Spectrometer and Multi-angle Imaging SpectroRadiometer, respectively. CERES data show that clouds have a net radiative warming influence during La Niña conditions and a net cooling influence during El Niño, but the magnitude of the anomalies varies greatly from one ENSO event to another. Regional cloud-radiation variations among several Terra and A-Train instruments show consistent patterns and exhibit marked fluctuations at monthly timescales in response to tropical atmosphere-ocean dynamical processes associated with ENSO and Madden-Julian Oscillation.

  3. Dissecting genealogy and cell cycle as sources of cell-to-cell variability in MAPK signaling using high-throughput lineage tracking

    PubMed Central

    Ricicova, Marketa; Hamidi, Mani; Quiring, Adam; Niemistö, Antti; Emberly, Eldon; Hansen, Carl L.

    2013-01-01

    Cells, even those having identical genotype, exhibit variability in their response to external stimuli. This variability arises from differences in the abundance, localization, and state of cellular components. Such nongenetic differences are likely heritable between successive generations and can also be influenced by processes such as cell cycle, age, or interplay between different pathways. To address the contribution of nongenetic heritability and cell cycle in cell-to-cell variability we developed a high-throughput and fully automated microfluidic platform that allows for concurrent measurement of gene expression, cell-cycle periods, age, and lineage information under a large number of temporally changing medium conditions and using multiple strains. We apply this technology to examine the role of nongenetic inheritance in cell heterogeneity of yeast pheromone signaling. Our data demonstrate that the capacity to respond to pheromone is passed across generations and that the strength of the response correlations between related cells is affected by perturbations in the signaling pathway. We observe that a ste50Δ mutant strain exhibits highly heterogeneous response to pheromone originating from a unique asymmetry between mother and daughter response. On the other hand, fus3Δ cells were found to exhibit an unusually high correlation between mother and daughter cells that arose from a combination of extended cell-cycle periods of fus3Δ mothers, and decreased cell-cycle modulation of the pheromone pathway. Our results contribute to the understanding of the origins of cell heterogeneity and demonstrate the importance of automated platforms that generate single-cell data on several parameters. PMID:23803859

  4. Variability, heritability and genetic advance in some agronomic and forage quality characters of spring triticale in western Canada.

    PubMed

    Aljarrah, Mazen; Oatway, Lori; Albers, Susan; Bergen, Colin

    2014-01-01

    The aim of this study was to estimate variability, broad sense heritability, and genetic advance for dry matter yield (DMY), days to anthesis (ANTH), plant height (HT), in-vitro fiber digestibility-30h (IVFD), lignin (LIGN), starch (STAR %), crude protein content (CP %), acid detergent fiber (ADF) and neutral detergent fiber (NDF) in spring triticale genotypes. Eighteen genotypes were tested at the Field Crop Development Centre (FCDC) in Lacombe, Alberta in 2010-2011 and 2011-2012 growing season. The experimental design was randomized complete block design with 3 replicates. Combined analysis of variance was carried out using SAS Enterprise 4.2 statistical package. Heritability was estimated following the variance component method. Simple correlation coefficients were determined among all traits using two years average data. The genotype mean squares were significant (P ≤ 0.05) for DMY, ANTH, HT, IFVD, ADF, NDF, STAR %, LIGN, and CP %. The effect of year was also highly significant on all studied traits. The phenotypic coefficient of variation was higher than the genetic coefficient of variation for all traits, indicating high influence of the environment on these traits. The significant genetic variability and the high heritability combined with high genetic advance of HT, STAR% and ADF in triticale genotypes suggested that selection could be successfully practiced for those traits. Correlation analysis showed significant and positive correlation of DMY with ANTH and HT, indicating that late and tall genotypes are more suitable as a forage type and they tend to produce more biomass yield. However, DMY did not show any significant correlation with the digestibility. IVFD and STAR % were negatively correlated with LIGN. In general, these results indicated that breeding for low lignin and high starch content will improve the digestibility in triticale genotypes. The preliminary results of this study were promising. Further research must include more diverse

  5. Supercharged two-cycle engines employing novel single element reciprocating shuttle inlet valve mechanisms and with a variable compression ratio

    NASA Technical Reports Server (NTRS)

    Wiesen, Bernard (Inventor)

    2008-01-01

    This invention relates to novel reciprocating shuttle inlet valves, effective with every type of two-cycle engine, from small high-speed single cylinder model engines, to large low-speed multiple cylinder engines, employing spark or compression ignition. Also permitting the elimination of out-of-phase piston arrangements to control scavenging and supercharging of opposed-piston engines. The reciprocating shuttle inlet valve (32) and its operating mechanism (34) is constructed as a single and simple uncomplicated member, in combination with the lost-motion abutments, (46) and (48), formed in a piston skirt, obviating the need for any complex mechanisms or auxiliary drives, unaffected by heat, friction, wear or inertial forces. The reciprocating shuttle inlet valve retains the simplicity and advantages of two-cycle engines, while permitting an increase in volumetric efficiency and performance, thereby increasing the range of usefulness of two-cycle engines into many areas that are now dominated by the four-cycle engine.

  6. Effect of physical property of supporting media and variable hydraulic loading on hydraulic characteristics of advanced onsite wastewater treatment system.

    PubMed

    Sharma, Meena Kumari; Kazmi, Absar Ahmad

    2015-01-01

    A laboratory-scale study was carried out to investigate the effects of physical properties of the supporting media and variable hydraulic shock loads on the hydraulic characteristics of an advanced onsite wastewater treatment system. The system consisted of two upflow anaerobic reactors (a septic tank and an anaerobic filter) accommodated within a single unit. The study was divided into three phases on the basis of three different supporting media (Aqwise carriers, corrugated ring and baked clay) used in the anaerobic filter. Hydraulic loadings were based on peak flow factor (PFF), varying from one to six, to simulate the actual conditions during onsite wastewater treatment. Hydraulic characteristics of the system were identified on the basis of residence time distribution analyses. The system showed a very good hydraulic efficiency, between 0.86 and 0.93, with the media of highest porosity at the hydraulic loading of PFF≤4. At the higher hydraulic loading of PFF 6 also, an appreciable hydraulic efficiency of 0.74 was observed. The system also showed good chemical oxygen demand and total suspended solids removal efficiency of 80.5% and 82.3%, respectively at the higher hydraulic loading of PFF 6. Plug-flow dispersion model was found to be the most appropriate one to describe the mixing pattern of the system, with different supporting media at variable loading, during the tracer study. PMID:25428652

  7. Carbon cycle. The dominant role of semi-arid ecosystems in the trend and variability of the land CO₂ sink.

    PubMed

    Ahlström, Anders; Raupach, Michael R; Schurgers, Guy; Smith, Benjamin; Arneth, Almut; Jung, Martin; Reichstein, Markus; Canadell, Josep G; Friedlingstein, Pierre; Jain, Atul K; Kato, Etsushi; Poulter, Benjamin; Sitch, Stephen; Stocker, Benjamin D; Viovy, Nicolas; Wang, Ying Ping; Wiltshire, Andy; Zaehle, Sönke; Zeng, Ning

    2015-05-22

    The growth rate of atmospheric carbon dioxide (CO2) concentrations since industrialization is characterized by large interannual variability, mostly resulting from variability in CO2 uptake by terrestrial ecosystems (typically termed carbon sink). However, the contributions of regional ecosystems to that variability are not well known. Using an ensemble of ecosystem and land-surface models and an empirical observation-based product of global gross primary production, we show that the mean sink, trend, and interannual variability in CO2 uptake by terrestrial ecosystems are dominated by distinct biogeographic regions. Whereas the mean sink is dominated by highly productive lands (mainly tropical forests), the trend and interannual variability of the sink are dominated by semi-arid ecosystems whose carbon balance is strongly associated with circulation-driven variations in both precipitation and temperature. PMID:25999504

  8. Ecotypic variability in the metabolic response of seeds to diurnal hydration-dehydration cycles and its relationship to seed vigor.

    PubMed

    Bai, Bing; Sikron, Noga; Gendler, Tanya; Kazachkova, Yana; Barak, Simon; Grafi, Gideon; Khozin-Goldberg, Inna; Fait, Aaron

    2012-01-01

    Seeds in the seed bank experience diurnal cycles of imbibition followed by complete dehydration. These conditions pose a challenge to the regulation of germination. The effect of recurring hydration-dehydration (Hy-Dh) cycles were tested on seeds from four Arabidopsis thaliana accessions [Col-0, Cvi, C24 and Ler]. Diurnal Hy-Dh cycles had a detrimental effect on the germination rate and on the final percentage of germination in Col-0, Cvi and C24 ecotypes, but not in the Ler ecotype, which showed improved vigor following the treatments. Membrane permeability measured by ion conductivity was generally increased following each Hy-Dh cycle and was correlated with changes in the redox status represented by the GSSG/GSH (oxidized/reduced glutathione) ratio. Among the ecotypes, Col-0 seeds displayed the highest membrane permeability, whilst Ler was characterized by the greatest increase in electrical conductivity following Hy-Dh cycles. Following Dh 2 and Dh 3, the respiratory activity of Ler seeds significantly increased, in contrast to the other ecotypes, indicative of a dramatic shift in metabolism. These differences were associated with accession-specific content and patterns of change of (i) cell wall-related laminaribiose and mannose; (ii) fatty acid composition, specifically of the unsaturated oleic acid and α-linoleic acid; and (iii) asparagine, ornithine and the related polyamine putrescine. Furthermore, in the Ler ecotype the content of the tricarboxylic acid (TCA) cycle intermediates fumarate, succinate and malate increased in response to dehydration, in contrast to a decrease in the other three ecotypes. These findings provide a link between seed respiration, energy metabolism, fatty acid β-oxidation, nitrogen mobilization and membrane permeability and the improved germination of Ler seeds following Hy-Dh cycles. PMID:22156384

  9. Zirconia-magnesia inert matrix fuel and waste form: Synthesis, characterization and chemical performance in an advanced fuel cycle

    NASA Astrophysics Data System (ADS)

    Holliday, Kiel Steven

    There is a significant buildup in plutonium stockpiles throughout the world, because of spent nuclear fuel and the dismantling of weapons. The radiotoxicity of this material and proliferation risk has led to a desire for destroying excess plutonium. To do this effectively, it must be fissioned in a reactor as part of a uranium free fuel to eliminate the generation of more plutonium. This requires an inert matrix to volumetrically dilute the fissile plutonium. Zirconia-magnesia dual phase ceramic has been demonstrated to be a favorable material for this task. It is neutron transparent, zirconia is chemically robust, magnesia has good thermal conductivity and the ceramic has been calculated to conform to current economic and safety standards. This dissertation contributes to the knowledge of zirconia-magnesia as an inert matrix fuel to establish behavior of the material containing a fissile component. First, the zirconia-magnesia inert matrix is synthesized in a dual phase ceramic containing a fissile component and a burnable poison. The chemical constitution of the ceramic is then determined. Next, the material performance is assessed under conditions relevant to an advanced fuel cycle. Reactor conditions were assessed with high temperature, high pressure water. Various acid solutions were used in an effort to dissolve the material for reprocessing. The ceramic was also tested as a waste form under environmental conditions, should it go directly to a repository as a spent fuel. The applicability of zirconia-magnesia as an inert matrix fuel and waste form was tested and found to be a promising material for such applications.

  10. Advanced Fuel Cycle Initiative AFC-1D, AFC-1G, and AFC-1H End of FY-07 Irradiation Report

    SciTech Connect

    Debra J Utterbeck; Gray S Chang; Misit A Lillo

    2007-09-01

    The purpose of the U.S. Advanced Fuel Cycle Initiative (AFCI), now within the broader context of the Global Nuclear Energy Partnership (GNEP), is to develop and demonstrate the technologies needed to transmute the long-lived transuranic isotopes contained in spent nuclear fuel into shorter-lived fission products. Success in this undertaking could potentially dramatically decrease the volume of material requiring disposal with attendant reductions in long-term radio-toxicity and heat load of high-level waste sent to a geologic repository. One important component of the technology development is investigation of irradiation/transmutation effects on actinide-bearing metallic fuel forms containing plutonium, neptunium, americium (and possibly curium) isotopes. Goals of this initiative include addressing the limited irradiation performance data available on metallic fuels with high concentrations of Pu, Np and Am, as are envisioned for use as actinide transmutation fuels. The AFC-1 irradiation experiments of transmutation fuels are expected to provide irradiation performance data on non-fertile and low-fertile fuel forms specifically, irradiation growth and swelling, helium production, fission gas release, fission product and fuel constituent migration, fuel phase equilibria, and fuel-cladding chemical interaction. Contained in this report are the to-date physics evaluations performed on three of the AFC-1 experiments; AFC-1D, AFC-1G and AFC-1H. The AFC-1D irradiation experiment consists of metallic non-fertile fuel compositions with minor actinides for potential use in accelerator driven systems and AFC-1G and AFC-1H irradiation experiments are part of the fast neutron reactor fuel development effort. The metallic fuel experiments and nitride experiment are high burnup analogs to previously irradiated experiments and are to be irradiated to = 40 at.% burnup.

  11. Zeolite Y adsorbents with high vapor uptake capacity and robust cycling stability for potential applications in advanced adsorption heat pumps

    SciTech Connect

    Li, XS; Narayanan, S; Michaelis, VK; Ong, TC; Keeler, EG; Kim, H; Mckay, IS; Griffin, RG; Wang, EN

    2015-01-01

    Modular and compact adsorption heat pumps (AHPs) promise an energy-efficient alternative to conventional vapor compression based heating, ventilation and air conditioning systems. A key element in the advancement of AHPs is the development of adsorbents with high uptake capacity, fast intracrystalline diffusivity and durable hydrothermal stability. Herein, the ion exchange of NaY zeolites with ingoing Mg2+ ions is systematically studied to maximize the ion exchange degree (IED) for improved sorption performance. It is found that beyond an ion exchange threshold of 64.1%, deeper ion exchange does not benefit water uptake capacity or characteristic adsorption energy, but does enhance the vapor diffusivity. In addition to using water as an adsorbate, the uptake properties of Mg, Na-Y zeolites were investigated using 20 wt.% MeOH aqueous solution as a novel anti-freeze adsorbate, revealing that the MeOH additive has an insignificant influence on the overall sorption performance. We also demonstrated that the lab-scale synthetic scalability is robust, and that the tailored zeolites scarcely suffer from hydrothermal stability even after successive 108-fold adsorption/desorption cycles. The samples were analyzed using N-2 sorption, Al-27/Si-29 MAS NMR spectroscopy, ICP-AES, dynamic vapor sorption, SEM, Fick's 2nd law and D-R equation regressions. Among these, close examination of sorption isotherms for H2O and N-2 adsorbates allows us to decouple and extract some insightful information underlying the complex water uptake phenomena. This work shows the promising performance of our modified zeolites that can be integrated into various AHP designs for buildings, electronics, and transportation applications. (C) 2014 Elsevier Inc. All rights reserved.

  12. Calendar-Life and Cycle-Life Studies of Advanced Technology Development Program Generation 1 Lithium-Ion Batteries

    SciTech Connect

    Wright, Randy Ben; Motloch, Chester George; Belt, Jeffrey R; Christophersen, Jon Petter; Ho, Chinh Dac; Richardson, Roger Allen; Bloom, I.; Jones, S. A.; Battaglia, Vincent S.; Henriksen, G. L.; Unkelhaeuser, T.; Ingersoll, D.; Case, H. L.; Rogers, S. A.; Sutula, R. A.

    2002-08-01

    This paper presents the test results and life modeling of special calendar- and cycle-life tests conducted on 18650-size generation 1 (Gen 1) lithium-ion battery cells (nominal capacity of 0.9 Ah; 3.0–4.1 V rating) developed to establish a baseline chemistry and performance for the Department of Energy sponsored advanced technology development (ATD) program. Electrical performance testing was conducted at the Argonne National Laboratory (ANL), Sandia National Laboratory (SNL) and the Idaho National Engineering and Environmental Laboratory (INEEL). As part of the electrical performance testing, a new calendar-life test protocol was used. The test consisted of a once per day discharge and charge pulse designed to have minimal impact on the cell yet establish its performance over a period of time such that the calendar-life of the cell could be determined. The calendar-life test matrix included two states-of-charge (SOCs) (i.e. 60 and 80%) and four test temperatures (40, 50, 60 and 70 °C). Discharge and regen resistances were calculated from the test data. Results indicate that both the discharge and regen resistances increased non-linearly as a function of the test time. The magnitude of the resistances depended on the temperature and SOC at which the test was conducted. Both resistances had a non-linear increase with respect to time at test temperature. The discharge resistances are greater than the regen resistances at all of the test temperatures of 40, 50, 60 and 70 °C. For both the discharge and regen resistances, generally the higher the test temperature, the lower the resistance.

  13. Development of Cesium and Strontium Separation and Immobilization Technologies in Support of an Advanced Nuclear Fuel Cycle

    SciTech Connect

    Jack D. Law; Troy G. Garn; R. Scott Herbst; David H. Meikrantz; Dean R. Peterman; Catherine L. Riddle; Terry A. Todd; Julie L. Tripp

    2006-02-01

    As part of the Advanced Fuel Cycle Initiative, two solvent extraction technologies are being developed at the Idaho National Laboratory to simultaneously separate cesium and strontium from dissolved spent nuclear fuel. The chlorinated cobalt dicarbollide/polyethylene glycol (CCD/PEG) process utilizes a solvent consisting of chlorinated cobalt dicarbollide for the extraction of Cs and polyethylene glycol for the synergistic extraction of Sr in a phenyltrifluoromethyl sulfone diluent. Countercurrent flowsheets have been designed and tested on simulated and actual spent nuclear fuel feed streams with both cesium and strontium removal efficiencies of greater than 99%. The Fission Product Extraction (FPEX) process is based on two highly-specific extractants: 4,4',(5')-Di-(t-butyldicyclo-hexano)-18-crown-6 (DtBuCH18C6) for the extraction of Sr and Calix[4]arene-bis-(tert-octylbenzo-crown-6) (BOBCalixC6) for the extraction of Cs. Laboratory test results of the FPEX process, using simulated feed solution spiked with radiotracers, indicate good Cs and Sr extraction and stripping performance. A preliminary solvent extraction flowsheet for the treatment of spent nuclear fuel with the FPEX process has been developed, and testing of the flowsheet with simulated spent nuclear fuel solutions is planned in the near future. Steam reforming is currently being developed for stabilization of the Cs/Sr product stream because it can produce a solid waste form while retaining the Cs and Sr in the solid, destroy the nitrates and organics present in these aqueous solutions, and convert the Cs and Sr into leach resistant aluminosilicate minerals. A bench-scale steam reforming pilot plant has been operated with several potential feed compositions and steam reformed product has been generated and analyzed.

  14. Zeolite Y Adsorbents with High Vapor Uptake Capacity and Robust Cycling Stability for Potential Applications in Advanced Adsorption Heat Pumps

    PubMed Central

    Li, Xiansen; Narayanan, Shankar; Michaelis, Vladimir K.; Ong, Ta-Chung; Keeler, Eric G.; Kim, Hyunho; McKay, Ian S.; Griffin, Robert G.; Wang, Evelyn N.

    2014-01-01

    Modular and compact adsorption heat pumps (AHPs) promise an energy-efficient alternative to conventional vapor compression based heating, ventilation and air conditioning systems. A key element in the advancement of AHPs is the development of adsorbents with high uptake capacity, fast intracrystalline diffusivity and durable hydrothermal stability. Herein, the ion exchange of NaY zeolites with ingoing Mg2+ ions is systematically studied to maximize the ion exchange degree (IED) for improved sorption performance. It is found that beyond an ion exchange threshold of 64.1%, deeper ion exchange does not benefit water uptake capacity or characteristic adsorption energy, but does enhance the vapor diffusivity. In addition to using water as an adsorbate, the uptake properties of Mg,Na-Y zeolites were investigated using 20 wt.% MeOH aqueous solution as a novel anti-freeze adsorbate, revealing that the MeOH additive has an insignificant influence on the overall sorption performance. We also demonstrated that the labscale synthetic scalability is robust, and that the tailored zeolites scarcely suffer from hydrothermal stability even after successive 108-fold adsorption/desorption cycles. The samples were analyzed using N2 sorption, 27Al/29Si MAS NMR spectroscopy, ICP-AES, dynamic vapor sorption, SEM, Fick’s 2nd law and D-R equation regressions. Among these, close examination of sorption isotherms for H2O and N2 adsorbates allows us to decouple and extract some insightful information underlying the complex water uptake phenomena. This work shows the promising performance of our modified zeolites that can be integrated into various AHP designs for buildings, electronics, and transportation applications. PMID:25395877

  15. Zeolite Y Adsorbents with High Vapor Uptake Capacity and Robust Cycling Stability for Potential Applications in Advanced Adsorption Heat Pumps.

    PubMed

    Li, Xiansen; Narayanan, Shankar; Michaelis, Vladimir K; Ong, Ta-Chung; Keeler, Eric G; Kim, Hyunho; McKay, Ian S; Griffin, Robert G; Wang, Evelyn N

    2015-01-01

    Modular and compact adsorption heat pumps (AHPs) promise an energy-efficient alternative to conventional vapor compression based heating, ventilation and air conditioning systems. A key element in the advancement of AHPs is the development of adsorbents with high uptake capacity, fast intracrystalline diffusivity and durable hydrothermal stability. Herein, the ion exchange of NaY zeolites with ingoing Mg(2+) ions is systematically studied to maximize the ion exchange degree (IED) for improved sorption performance. It is found that beyond an ion exchange threshold of 64.1%, deeper ion exchange does not benefit water uptake capacity or characteristic adsorption energy, but does enhance the vapor diffusivity. In addition to using water as an adsorbate, the uptake properties of Mg,Na-Y zeolites were investigated using 20 wt.% MeOH aqueous solution as a novel anti-freeze adsorbate, revealing that the MeOH additive has an insignificant influence on the overall sorption performance. We also demonstrated that the labscale synthetic scalability is robust, and that the tailored zeolites scarcely suffer from hydrothermal stability even after successive 108-fold adsorption/desorption cycles. The samples were analyzed using N2 sorption, (27)Al/(29)Si MAS NMR spectroscopy, ICP-AES, dynamic vapor sorption, SEM, Fick's 2(nd) law and D-R equation regressions. Among these, close examination of sorption isotherms for H2O and N2 adsorbates allows us to decouple and extract some insightful information underlying the complex water uptake phenomena. This work shows the promising performance of our modified zeolites that can be integrated into various AHP designs for buildings, electronics, and transportation applications. PMID:25395877

  16. Advanced heat pump for the recovery of volatile organic compounds. Phase 1, Conceptual design of an advanced Brayton cycle heat pump for the recovery of volatile organic compounds: Final report

    SciTech Connect

    Not Available

    1992-03-01

    Emissions of Volatile Organic Compounds (VOC) from stationary industrial and commercial sources represent a substantial portion of the total US VOC emissions. The ``Toxic-Release Inventory`` of The US Environmental Protection Agency estimates this to be at about 3 billion pounds per year (1987 estimates). The majority of these VOC emissions are from coating processes, cleaning processes, polymer production, fuel production and distribution, foam blowing,refrigerant production, and wood products production. The US Department of Energy`s (DOE) interest in the recovery of VOC stems from the energy embodied in the recovered solvents and the energy required to dispose of them in an environmentally acceptable manner. This Phase I report documents 3M`s work in close working relationship with its subcontractor Nuclear Consulting Services (Nucon) for the preliminary conceptual design of an advanced Brayton cycle heat pump for the recovery of VOC. Nucon designed Brayton cycle heat pump for the recovery of methyl ethyl ketone and toluene from coating operations at 3M Weatherford, OK, was used as a base line for the work under cooperative agreement between 3M and ODE. See appendix A and reference (4) by Kovach of Nucon. This cooperative agreement report evaluates and compares an advanced Brayton cycle heat pump for solvent recovery with other competing technologies for solvent recovery and reuse. This advanced Brayton cycle heat pump is simple (very few components), highly reliable (off the shelf components), energy efficient and economically priced.

  17. Effect of deception and expected exercise duration on psychological and physiological variables during treadmill running and cycling.

    PubMed

    Eston, Roger; Stansfield, Ralph; Westoby, Paul; Parfitt, Gaynor

    2012-04-01

    Effects of deception and expected duration on the rating of perceived exertion (RPE), affect, and heart rate (HR) were examined during treadmill (n=12) and cycling (n=8) exercise. Participants completed three conditions: (1) 20 MIN-exercise for 20 min, stop after 20 min; (2) 10 MIN-exercise for 10 min, in 10th min be told to exercise for 10 min more; and (3) UNKNOWN-no information about duration. Intensities were set at 70% and 65% of peak oxygen uptake for treadmill and cycling, respectively. RPE increased (treadmill) and affect decreased (treadmill and cycling) in the absence of changes in HR and oxygen uptake in the 10 MIN conditions. These changes suggest a disruption to a feed-forward/feedback system. The lower HR in the UNKNOWN conditions suggests a subconscious attempt to conserve energy when the duration of the exercise task is unknown. PMID:22220852

  18. Development of a 1-week cycle menu for an Advanced Life Support System (ALSS) utilizing practical biomass production data from the Closed Ecology Experiment Facilities (CEEF).

    PubMed

    Masuda, Tsuyoshi; Arai, Ryuuji; Komatsubara, Osamu; Tako, Yasuhiro; Harashima, Emiko; Nitta, Keiji

    2005-01-01

    Productivities of 29 crops in the Closed Ecology Experiment Facilities (CEEF) were measured. Rice and soybean showed higher productivities than these given by the Advanced Life Support System Modeling and Analysis Project Baseline Values and Assumption Document (BVAD), but productivities of some other crops, such as potato and sweet potato, were lower. The cultivation data were utilized to develop a 1-week cycle menu for Closed Habitation Experiment. The menu met most of the nutritional requirements. Necessary cultivation area per crew was estimated to be 255 m2. Results from this study can be used to help design the future Advanced Life Support System (ALSS) including the CEEF. PMID:15742533

  19. Information transfer across the scales of climate variability: The effect of the 7-8 year cycle on the annual and interannual scales

    NASA Astrophysics Data System (ADS)

    Palus, Milan; Jajcay, Nikola; Hlinka, Jaroslav; Kravtsov, Sergey; Tsonis, Anastasios

    2016-04-01

    Complexity of the climate system stems not only from the fact that it is variable over a huge range of spatial and temporal scales, but also from the nonlinear character of the climate system that leads to interactions of dynamics across scales. The dynamical processes on large time scales influence variability on shorter time scales. This nonlinear phenomenon of cross-scale causal interactions can be observed due to the recently introduced methodology [1] which starts with a wavelet decomposition of a multi-scale signal into quasi-oscillatory modes of a limited bandwidth, described using their instantaneous phases and amplitudes. Then their statistical associations are tested in order to search for interactions across time scales. An information-theoretic formulation of the generalized, nonlinear Granger causality [2] uncovers causal influence and information transfer from large-scale modes of climate variability with characteristic time scales from years to almost a decade to regional temperature variability on short time scales. In analyses of air temperature records from various European locations, a quasioscillatory phenomenon with the period around 7-8 years has been identified as the factor influencing variability of surface air temperature (SAT) on shorter time scales. Its influence on the amplitude of the SAT annual cycle was estimated in the range 0.7-1.4 °C and the effect on the overall variability of the SAT anomalies (SATA) leads to the changes 1.5-1.7 °C in the annual SATA means. The strongest effect of the 7-8 year cycle was observed in the winter SATA means where it reaches 4-5 °C in central European station and reanalysis data [3]. This study is supported by the Ministry of Education, Youth and Sports of the Czech Republic within the Program KONTAKT II, Project No. LH14001. [1] M. Palus, Phys. Rev. Lett. 112 078702 (2014) [2] M. Palus, M. Vejmelka, Phys. Rev. E 75, 056211 (2007) [3] N. Jajcay, J. Hlinka, S. Kravtsov, A. A. Tsonis, M. Palus, Time

  20. Climatology, Natural Cycles, and Modes of Interannual Variability of the Great Plains Low-Level Jet as Assimilated by the GEOS-1 Data Analysis System

    NASA Technical Reports Server (NTRS)

    Helfand, H. M.; Schubert, S. D.; Atlas, Robert (Technical Monitor)

    2002-01-01

    Despite the fact that the low-level jet of the southern Great Plains (the GPLLJ) of the U.S. is primarily a nocturnal phenomenon that virtually vanishes during the daylight hours, it is one of the most persistent and stable features of the low-level continental flow during the warm-season months, May through August. We have first used significant-level data to validate the skill of the GEOS-1 Data Assimilation System (DAS) in realistically detecting this jet and inferring its structure and evolution. We have then carried out a 15-year reanalysis with the GEOS-1 DAS to determine and validate its climatology and mean diurnal cycle and to study its interannual variability. Interannual variability of the GPLLJ is much smaller than mean diurnal and random intraseasonal variability and comparable in magnitude, but not location, to mean seasonal variability. There are three maxima of interannual low-level meridional flow variability of the GPLLJ over the upper Great Plains, southeastern Texas, and the western Gulf of Mexico. Cross-sectional profiles of mean southerly wind through the Texas maximum remain relatively stable and recognizable from year to year with only its eastward flank showing significant variability. This variability, however, exhibits a distinct, biennial oscillation during the first six years of the reanalysis period and only then. Each of the three variability maxima corresponds to a spatially coherent, jet-like pattern of low-level flow interannual variability. There are three prominent modes of interannual. variability. These include the intermittent biennial oscillation (IBO), local to the Texas maximum. Its signal is evident in surface pressure, surface temperature, ground wetness and upper air flow, as well. A larger-scale continental convergence pattern (CCP) of covariance, exhibiting strong anti-correlation between the flow near the Texas and the upper Great Plains variability maxima, is revealed only when the IBO is removed from the interannual

  1. Relations of Cognitive and Motivational Variables with Students' Human Circulatory System Achievement in Traditional and Learning Cycle Classrooms

    ERIC Educational Resources Information Center

    Sadi, Özlem; Çakiroglu, Jale

    2014-01-01

    This study is aimed at investigating the relationships among students' relevant prior knowledge, meaningful learning orientation, reasoning ability, self-efficacy, locus of control, attitudes toward biology and achievement with the human circulatory system (HCS) using the learning cycle (LC) and the traditional classroom setting. The study…

  2. Calendar- and cycle-life studies of advanced technology development program generation 1 lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Wright, R. B.; Motloch, C. G.; Belt, J. R.; Christophersen, J. P.; Ho, C. D.; Richardson, R. A.; Bloom, I.; Jones, S. A.; Battaglia, V. S.; Henriksen, G. L.; Unkelhaeuser, T.; Ingersoll, D.; Case, H. L.; Rogers, S. A.; Sutula, R. A.

    This paper presents the test results and life modeling of special calendar- and cycle-life tests conducted on 18650-size generation 1 (Gen 1) lithium-ion battery cells (nominal capacity of 0.9 Ah; 3.0-4.1 V rating) developed to establish a baseline chemistry and performance for the Department of Energy sponsored advanced technology development (ATD) program. Electrical performance testing was conducted at the Argonne National Laboratory (ANL), Sandia National Laboratory (SNL) and the Idaho National Engineering and Environmental Laboratory (INEEL). As part of the electrical performance testing, a new calendar-life test protocol was used. The test consisted of a once per day discharge and charge pulse designed to have minimal impact on the cell yet establish its performance over a period of time such that the calendar-life of the cell could be determined. The calendar-life test matrix included two states-of-charge (SOCs) (i.e. 60 and 80%) and four test temperatures (40, 50, 60 and 70 °C). Discharge and regen resistances were calculated from the test data. Results indicate that both the discharge and regen resistances increased non-linearly as a function of the test time. The magnitude of the resistances depended on the temperature and SOC at which the test was conducted. Both resistances had a non-linear increase with respect to time at test temperature. The discharge resistances are greater than the regen resistances at all of the test temperatures of 40, 50, 60 and 70 °C. For both the discharge and regen resistances, generally the higher the test temperature, the lower the resistance. The measured resistances were then used to develop an empirical model that was used to predict the calendar-life of the cells. This model accounted for the time, temperature and SOC of the batteries during the calendar-life test. The functional form of the model is given by: R( t, T,SOC)= A( T, SOC) F( t)+ B( T, SOC), where t is the time at test temperature, T the test temperature

  3. Interannual variability of the Arctic freshwater cycle in the second half of the twentieth century in a regionally coupled climate model

    NASA Astrophysics Data System (ADS)

    Niederdrenk, Anne Laura; Sein, Dmitry V.; Mikolajewicz, Uwe

    2016-03-01

    We use a regionally coupled ocean-sea ice-atmosphere-hydrological discharge model to investigate the influence of changes in the atmospheric large-scale circulation on the interannual variability of the Arctic freshwater (FW) components. This model includes all sinks and sources of FW and allows for the analysis of a closed FW cycle in the Arctic. We show that few atmospheric winter modes explain large parts of the interannual variability of the Arctic FW cycle. A strong Icelandic low causing anomalous strong westerlies over the North Atlantic leads to warmer and wetter conditions over Eurasia. The ocean circulation is then characterized by a strong transpolar drift leading to increased export of FW in liquid and solid form into the North Atlantic. In contrast to this, a weaker than usual Icelandic low and a strong Siberian high is associated with a strong Beaufort Gyre and thus an accumulation of FW within the Arctic Ocean. Not only specific winter conditions but also increased precipitation in late spring and summer, caused by enhanced cyclone activity over land, lead to increased Eurasian runoff, which is responsible for most of the variability in Arctic river runoff.

  4. The study of TeV variability and the duty cycle of Mrk 421 from 3 Yr of observations with the milagro observatory

    SciTech Connect

    Abdo, A. A.; Abeysekara, A. U.; Barber, A. S.; Allen, B. T.; Chen, C.; Delay, R. S.; Aune, T.; Berley, D.; Braun, J.; Goodman, J. A.; Christopher, G. E.; DeYoung, T.; Dingus, B. L.; Hoffman, C. M.; Imran, A.; Ellsworth, R. W.; Fraija, N.; González, M. M.; Hays, E.; Hüntemeyer, P. H.; and others

    2014-02-20

    TeV-flaring activity with timescales as short as tens of minutes and an orphan TeV flare have been observed from the blazar Markarian 421 (Mrk 421). The TeV emission from Mrk 421 is believed to be produced by leptonic synchrotron self-Compton (SSC) emission. In this scenario, correlations between the X-ray and the TeV fluxes are expected, TeV orphan flares are hardly explained, and the activity (measured as duty cycle) of the source at TeV energies is expected to be equal to or less than that observed in X-rays if only SSC is considered. To estimate the TeV duty cycle of Mrk 421 and to establish limits on its variability at different timescales, we continuously observed Mrk 421 with the Milagro observatory. Mrk 421 was detected by Milagro with a statistical significance of 7.1 standard deviations between 2005 September 21 and 2008 March 15. The observed spectrum is consistent with previous observations by VERITAS. We estimate the duty cycle of Mrk 421 for energies above 1 TeV for different hypotheses of the baseline flux and for different flare selections and we compared our results with the X-ray duty cycle estimated by Resconi et al. The robustness of the results is discussed.

  5. The Study of TeV Variability and the Duty Cycle of Mrk 421 from 3 Yr of Observations with the Milagro Observatory

    NASA Technical Reports Server (NTRS)

    Abdo, A. A.; Abeysekara, A. U.; Allen, B. T.; Aune, T.; Barber, A. S.; Berley, D.; Braun, J.; Chen, C.; Hays, E.; McEnery, J. E.

    2014-01-01

    TeV-flaring activity with timescales as short as tens of minutes and an orphan TeV flare have been observed from the blazar Markarian 421 (Mrk 421). The TeV emission from Mrk 421 is believed to be produced by leptonic synchrotron self-Compton (SSC) emission. In this scenario, correlations between the X-ray and the TeV fluxes are expected, TeV orphan flares are hardly explained, and the activity (measured as duty cycle) of the source at TeV energies is expected to be equal to or less than that observed in X-rays if only SSC is considered. To estimate the TeV duty cycle of Mrk 421 and to establish limits on its variability at different timescales, we continuously observed Mrk 421 with the Milagro observatory. Mrk 421 was detected by Milagro with a statistical significance of 7.1 standard deviations between 2005 September 21 and 2008 March 15. The observed spectrum is consistent with previous observations by VERITAS. We estimate the duty cycle of Mrk 421 for energies above 1 TeV for different hypotheses of the baseline flux and for different flare selections and we compared our results with the X-ray duty cycle estimated by Resconi et al. The robustness of the results is discussed.

  6. The Study of TeV Variability and the Duty Cycle of Mrk 421 from 3 yr of Observations with the Milagro Observatory

    NASA Astrophysics Data System (ADS)

    Abdo, A. A.; Abeysekara, A. U.; Allen, B. T.; Aune, T.; Barber, A. S.; Berley, D.; Braun, J.; Chen, C.; Christopher, G. E.; Delay, R. S.; DeYoung, T.; Dingus, B. L.; Ellsworth, R. W.; Fraija, N.; González, M. M.; Goodman, J. A.; Hays, E.; Hoffman, C. M.; Hüntemeyer, P. H.; Imran, A.; Kolterman, B. E.; Linnemann, J. T.; Marinelli, A.; McEnery, J. E.; Morgan, T.; Mincer, A. I.; Nemethy, P.; Patricelli, B.; Pretz, J.; Ryan, J. M.; Saz Parkinson, P. M.; Schneider, M.; Shoup, A.; Sinnis, G.; Smith, A. J.; Vasileiou, V.; Walker, G. P.; Williams, D. A.; Yodh, G. B.

    2014-02-01

    TeV-flaring activity with timescales as short as tens of minutes and an orphan TeV flare have been observed from the blazar Markarian 421 (Mrk 421). The TeV emission from Mrk 421 is believed to be produced by leptonic synchrotron self-Compton (SSC) emission. In this scenario, correlations between the X-ray and the TeV fluxes are expected, TeV orphan flares are hardly explained, and the activity (measured as duty cycle) of the source at TeV energies is expected to be equal to or less than that observed in X-rays if only SSC is considered. To estimate the TeV duty cycle of Mrk 421 and to establish limits on its variability at different timescales, we continuously observed Mrk 421 with the Milagro observatory. Mrk 421 was detected by Milagro with a statistical significance of 7.1 standard deviations between 2005 September 21 and 2008 March 15. The observed spectrum is consistent with previous observations by VERITAS. We estimate the duty cycle of Mrk 421 for energies above 1 TeV for different hypotheses of the baseline flux and for different flare selections and we compared our results with the X-ray duty cycle estimated by Resconi et al. The robustness of the results is discussed.

  7. T-R CYCLE CHARACTERIZATION AND IMAGING: ADVANCED DIAGNOSTIC METHODOLOGY FOR PETROLEUM RESERVOIR AND TRAP DETECTION AND DELINEATION

    SciTech Connect

    Ernest A. Mancini

    2004-06-01

    The principal research effort for Year 1 of the project is T-R cycle characterization and modeling. The research focus for the first nine (9) months of Year 1 is on outcrop study, well log analysis, seismic interpretation and data integration and for the remainder of the year the emphasis is on T-R cycle model development.

  8. T-R CYCLE CHARACTERIZATION AND IMAGING: ADVANCED DIAGNOSTIC METHODOLOGY FOR PETROLEUM RESERVOIR AND TRAP DETECTION AND DELINEATION

    SciTech Connect

    Ernest A. Mancini; William C. Parcell; Bruce S. Hart

    2004-03-05

    The principal research effort for Year 1 of the project is T-R cycle characterization and modeling. The research focus for the first nine (9) months of Year 1 is on outcrop study, well log analysis, seismic interpretation and data integration and for the remainder of the year the emphasis is on T-R cycle model development.

  9. Variability of foF2 over Rome and Gibilmanna during three solar cycles (1976-2000)

    NASA Astrophysics Data System (ADS)

    Pietrella, M.; Pezzopane, M.; Scotto, C.

    2012-05-01

    Hourly validated values of the F2-layer critical frequency (foF2) recorded at Rome, Italy (geographic coordinates 41.8°N, 12.5°E geomagnetic coordinates 42.0°N, 93.8°E), and Gibilmanna, Italy (geographic coordinates 37.6°N, 14.0°E geomagnetic coordinates 38.1°N, 93.6°E), along with the hourly quiet time reference values of foF2 (foF2QTRV) were considered around periods of minimum and maximum solar activity over the years 1976-2000. The foF2 data set was specifically organized in order to obtain an overall trend both for low and high solar activity, and different dispersion indices were used. The results obtained show that (1) at Rome, the foF2 variability is always greater during periods of high solar activity (HSA) in the hourly ranges 00:00-02:00 UT and 20:00-23:00 UT during winter months, and in the hourly ranges 00:00-10:00 UT and 04:00-16:00 UT during equinoctial and summer months respectively; (2) on the whole, around midday, for low solar activity (LSA), the foF2 variability is smaller at the equinoxes than at the solstices; for HSA, it is greater at equinoxes than at solstices; (3) for LSA, at Gibilmanna the foF2 variability is in general larger than at Rome, especially in summer, and it is characterized by a number of relative minimums and maximums greater than those observed at Rome; (4) at Rome, for both LSA and HSA, the passage of solar terminator at sunset significantly affects ionospheric variability in January, April, August, and November, at Gibilmanna in August, September, and November; (5) several variability peaks before sunrise and after sunset are observed in both stations; (6) on a monthly basis, for both LSA and HSA, a semiannual variation of foF2 variability is observed at both Rome and Gibilmanna; and (7) evidence of ionospheric variability at the typical heights of the F region, connected to upward propagating gravity waves triggered by solar terminator, is observed at Rome during some days characterized by HSA in the equinoctial

  10. Exploratory Analysis of the Effects of Anxiety on Specific Quantifiable Variables of African-American High School Students Enrolled in Advanced Academics

    ERIC Educational Resources Information Center

    James, Carmela N.

    2013-01-01

    The purpose of this study was to examine the attrition rate of the African American high school student enrolled in advanced academics by looking at the effects of specific quantifiable variables on state-trait anxiety scores. More specifically, this study was concerned with the influence of demographic and school related factors on the…

  11. Glacial-Interglacial, Orbital and Millennial-Scale Climate Variability for the Last Glacial Cycle at Shackleton Site U1385 based on Dinoflagellate Cysts

    NASA Astrophysics Data System (ADS)

    Datema, M.

    2015-12-01

    The Shackleton Site (IODP Expedition 339 Site U1385), located off the West-Portuguese Margin, preserves a continuous high-fidelity record of millennial-scale climate variability for the last several glacial cycles (~1.4 Myr) that can be correlated precisely to patterns observed in polar ice cores. In addition, rapid delivery of terrestrial material to the deep-sea environment allows the correlation of these marine records to European terrestrial climate records. This unique marine-ice-terrestrial linkage makes the Shackleton Site the ideal reference section for studying Quaternary abrupt climate change. The main objective of studying Site U1385 is to establish a marine reference section of Pleistocene climate change. We generated (sub)millennial-scale (~600 year interval) dinoflagellate cyst (dinocyst) assemblage records from Shackleton Site U1385 (IODP Expedition 339) to reconstruct sea surface temperature (SST) and productivity/upwelling over the last 152 kyrs. In addition, our approach allows for detailed land-sea correlations, because we also counted assemblages of pollen and spores from higher plants. Dinocyst SST and upwelling proxies, as well as warm/cold pollen proxies from Site U1385 show glacial-interglacial, orbital and stadial-interstadial climate variability and correlate very well to Uk'37, planktic foraminifer δ18O and Ca/Ti proxies of previously drilled Shackleton Sites and Greenland Ice Core δ18O. The palynological proxies capture (almost) all Dansgaard-Oeschger events of the last glacial cycle, also before ~70 ka, where millennial-scale variability is overprinted by precession. We compare the performance and results of the palynology of Site U1385 to proxies of previously drilled Shackleton Sites and conclude that palynology strengthens the potential of this site to form a multi-proxy reference section for millennial scale climate variability across the Pleistocene-Holocene. Finally, we will present a long-term paleoceanographic perspective down

  12. Damage accumulation in advanced metal-matrix composites under thermal cycling. Final report, 1 Oct 87-15 Oct 90

    SciTech Connect

    Taya, M.; Ramulu, M.; Armstrong, W.; Dunn, M.

    1991-02-25

    This research investigates the response to thermal cycling of a set of W-1%THO2 reinforced Fe-25CR-8Al-50Y superalloy matrix composites. During this research, unique composite materials were produced by powder metallurgical processing. These materials were three aligned composites of differing reinforcement aspect ratio, and a hierarchic composite which included fine diameter Al2O3 fibers. After hot isostatic pressing processing, specimen blanks were cut from the HIP billets by abrasive water jets after which specimens were turned using a conventional engine lathe. The specimens were then thermal sprayed with an oxidation resistant FeCrAlY coating identical to the matrix material. The specimens were then thermal cycled between 1100 C and 352 c and between 1100 C and 534 C for 100,500, or 750 cycles on a specially built thermal cycling machine. The dimensional change of each specimen was measured. It was found that the initial longitudinal growth per thermal cycle was small. After many thermal cycles however the longitudinal growth per thermal cycle became much larger. A severe growth of fiber-matrix interfacial damage was documented with scanning electron microscopy. The growth of two interfacial reaction phases was determined with a KEVEX dispersive x-ray analysis. The mechanical properties of the interfacial material were investigated with a Vickers microhardness test. Finally, the basic mechanical response of the material was investigated with room temperature tensile testing.

  13. Aqueous Iron-Sulfide Clusters in Variably Saturated Soil Systems: Implications for Iron Cycling and Fluid Flow

    NASA Astrophysics Data System (ADS)

    McGuire, J. T.; Hansen, D. J.; Mohanty, B. P.

    2008-12-01

    Iron and sulfur cycling is an important control on contaminant fate and transport, the availability of micronutrients and the physics of water flow. This study explores the effects of soil structure (i.e. layers, lenses, macropores, or fractures) on linked biogeochemical and hydrological processes involving Fe and S cycling in the vadose zone using packed soil columns. Three laboratory soil columns were constructed: a homogenized medium-grained sand, homogenized organic-rich loam, and a sand-over-loam layered column. Both upward and downward infiltration of water was evaluated during experiments to simulate rising water table and rainfall events respectively. Water samples extracted by lysimeter were analyzed for reduced species (including total sulfide, Fe(II), and FeSaq) voltammetrically using a mercury drop electrode. In addition to other reduced species, aqueous FeS clusters (FeSaq) were observed in two of the columns, with the greatest concentrations of FeSaq occurring in close proximity to the soil interface in the layered column. To our knowledge, this is the first documentation of aqueous FeS clusters in partially saturated sediments. The aqueous nature of FeSaq allows it to be transported instead of precipitating and suggests that current conceptual models of iron-sulfur cycling may need to be adapted to account for an aqueous phase. The presence of iron-rich soil aggregates near the soil interface may indicate that FeS clusters played a critical role in the formation of soil aggregates that subsequently caused up to an order of magnitude decrease in hydraulic conductivity.

  14. Advances in variable selection methods II: Effect of variable selection method on classification of hydrologically similar watersheds in three Mid-Atlantic ecoregions

    EPA Science Inventory

    Hydrological flow predictions in ungauged and sparsely gauged watersheds use regionalization or classification of hydrologically similar watersheds to develop empirical relationships between hydrologic, climatic, and watershed variables. The watershed classifications may be based...

  15. T-R CYCLE CHARACTERIZATION AND IMAGING: ADVANCED DIAGNOSTIC METHODOLOGY FOR PETROLEUM RESERVOIR AND TRAP DETECTION AND DELINEATION

    SciTech Connect

    Ernest A. Mancini

    2004-09-24

    The principal research effort for Year 1 of the project has been T-R cycle characterization and modeling. The research focus for the first nine (9) months of Year 1 was on outcrop study, well log analysis, seismic interpretation and data integration and for the remainder of the year the emphasis has been on T-R cycle model development. Information regarding the characteristics of T-R cycles has been assembled from the study of outcrops, from well log analyses, and from seismic reflection interpretation. From these studies, stratal boundaries separating T-R cycles have been found to be useful for the recognition and delineation of these cycles. The key stratal surfaces include subaerial unconformities, shoreface ravinement surfaces, transgressive surfaces, surfaces of maximum regression, and surfaces of maximum transgression. These surfaces can be identified and mapped in surface exposures and can be recognized in well log signatures and seismic reflection profiles as discontinuities. The findings from the study of outcrop, well log, and seismic reflection data are being integrated into a database for use in constructing a model for T-R cycle development.

  16. Inter-annual Variability of Biomass Burning Aerosol Optical Depth in Southern Amazonia, and the Impact of These Aerosols on the Diurnal Cycle of Solar Flux Reduction

    NASA Astrophysics Data System (ADS)

    Eck, T. F.; Holben, B. N.; Schafer, J. S.; Artaxo, P.; Yamasoe, M. A.; Procopio, A. S.; Prins, E. M.; Feltz, J. M.; Smirnov, A.; Dubovik, O.; Reid, J. S.

    2002-12-01

    The inter-annual variability of the magnitude of biomass burning in southern Amazonia has been relatively large over the last decade. The extent of the burning in the latter half of a given dry season (July-October) depends largely on the rainfall amount and timing, with drought years exhibiting many more fires and smoke than average. Additionally, new regulations aimed at controlling burning may also affect inter-annual variability. We present measurements of aerosol optical depth (AOD) from biomass burning smoke as measured by AERONET sites in Rondonia and Mato Grosso from 1993-2002. These AOD measurements are shown to follow similar inter-annual variability as the fire counts determined by the multi-spectral radiance measurements obtained with GOES-8. However, the AOD at these sites exhibit relatively little diurnal variation despite a very large diurnal cycle in satellite detected fire counts. In order to quantify the changes in the diurnal cycle of solar flux reduction as a result of aerosol attenuation at the peak of the burning season, we model the diurnal cycle of total shortwave (SW; 300-4000 nm), photosynthetically active radiation (PAR; 400-700 nm), and Ultraviolet- A (UVA; 320-400 nm) fluxes in mid-September using the AERONET monthly average AOD measurements (AOD(550 nm) = 1.11). These average diurnal cycle flux reductions show significant temporal delays in the morning for equivalent flux levels in all three spectral bands, of ~50 min to 2 hr 15 min at mid-morning (midpoint between sunrise and solar noon). The largest time delays in flux occur in the UVA band and the smallest in the total SW broadband due to a rapid decrease in AOD as wavelength increases for the accumulation mode smoke aerosols. The time delays in solar flux have implications for possible delay of the onset of cumulus convection, the shortening of the photo-period when plants photosynthesize, and reduced time interval for UVA fluxes which may have implications for photochemical

  17. Reproductive variables of Urotrygon rogersi (Batoidea: Urotrygonidae): a species with a triannual reproductive cycle in the eastern tropical Pacific Ocean.

    PubMed

    Mejía-Falla, P A; Navia, A F; Cortés, E

    2012-04-01

    Reproductive aspects of the round ray Urotrygon rogersi were studied based on 2005 specimens obtained in the artisanal shrimp fishery operating on the Colombian Pacific coast. Females reached greater maximum total length (L(T) ), disc width (W(D) ) and mass (M) (38·0 cm, 19·9 cm and 348 g) than males (32·5 cm, 17·0 cm and 165 g). Sex ratio of juveniles and adults was 1:1. Clasper length increased rapidly between 10·0 and 12·5 cm W(D) . The smallest mature male measured 10·5 cm W(D) and the largest immature individual 13·7 cm W(D) . Male first maturity was reached at 61·8% of maximum W(D) , and estimated W(D50) was between 11·5 and 11·8 cm. The smallest mature female measured 10·5 cm W(D) ; the size at first maturity was 52·8% of maximum W(D) , and estimated W(D50) was between 11·8 and 12·3 cm. Embryos were found in females ≥ 10·5 cm W(D) and maximum fecundity was three embryos per female (mode = 1) and varied with maternal size. Embryos were found in all months, but three birthing peaks per year were identified and a gestation period of 4-5 months estimated. Based on ovulation time, embryonic growth and parturition dates, a triannual reproductive cycle was inferred for this species, with overlapping ovarian and uterine cycles. These results suggest that U. rogersi has a reproductive strategy based on low fecundity, a rapid reproductive cycle (short ovulation and gestation time), three birth peaks per year and large embryos. This strategy probably allows U. rogersi to withstand the fishing pressure they are subject to on the Colombian Pacific coast. The results also suggest that the study area is an important nursery and reproductive area for this species. PMID:22497382

  18. Modeling effects of inter-annual variability in meteorological and land use conditions on coupled water and energy cycling in the cultivated African Sahel

    NASA Astrophysics Data System (ADS)

    Velluet, C.; Demarty, J.; Cappelaere, B.; Braud, I.; Boulain, N.; Favreau, G.; Charvet, G.; Ramier, D.; Issoufou, H.; Boucher, M.; Mainassara, I.; Chazarin, J.; Oï, M.; Yahou, H.; Benarrosh, N.; Ibrahim, M.

    2012-12-01

    In the dry tropics in general and in the African Sahel in particular, hydro-ecosystems are very sensitive to climate variability and land management. In the Niamey region of South-West Niger, a severe multi-decadal drought together with large-scale vegetation clearing coincided with an unexpected increase in surface and ground water resources. Such an apparent paradoxical situation illustrates the complex way in which climate and land cover interactions control the Sahelian water cycle dynamics. This stresses the importance of understanding and reliably modeling water/energy transfers in the local soil-plant-atmosphere system, under contrasted meteorological and surface conditions. This study investigates the effects of the inter-annual variability of meteorological and land use conditions on the coupled water and energy cycles in the cultivated Sahel over a 5-year period. This is based on a comprehensive multi-year field dataset acquired for a millet crop field and a fallow savannah, the two main land cover types of South-West Niger (Wankama catchment in the mesoscale AMMA-CATCH Niger observatory, part of the French-initiated RBV network). It includes atmospheric forcing, seasonal course of vegetation phenology, soil properties and model validation variables (net radiation, turbulent fluxes, soil heat/water profiles), for the two fields. The study area is typical of Central Sahel conditions, with 400-600 mm annual rainfall concentrated in the 4-5 month wet season. Soils are mainly sandy and prone to surface crusting, leading to a strong vertical contrast in hydrodynamic properties. The SiSPAT process-based model used solves the 1D mass and heat transfer system of equations in the soil, including vapor phase and coupled with a two-component (bare soil and vegetation) water and energy budget at the surface-atmosphere interface. The study explores whether such a model can be accurately calibrated and validated for the two sites using realistic-parameter values. The

  19. Simulating Lake-Groundwater Interactions During Decadal Climate Cycles: Accounting For Variable Lake Area In The Watershed

    NASA Astrophysics Data System (ADS)

    Virdi, M. L.; Lee, T. M.

    2009-12-01

    The volume and extent of a lake within the topo-bathymetry of a watershed can change substantially during wetter and drier climate cycles, altering the interaction of the lake with the groundwater flow system. Lake Starr and other seepage lakes in the permeable sandhills of central Florida are vulnerable to climate changes as they rely exclusively on rainfall and groundwater for inflows in a setting where annual rainfall and recharge vary widely. The groundwater inflow typically arrives from a small catchment area bordering the lake. The sinkhole origin of these lakes combined with groundwater pumping from underlying aquifers further complicate groundwater interactions. Understanding the lake-groundwater interactions and their effects on lake stage over multi-decadal climate cycles is needed to manage groundwater pumping and public expectation about future lake levels. The interdependence between climate, recharge, changing lake area and the groundwater catchment pose unique challenges to simulating lake-groundwater interactions. During the 10-year study period, Lake Starr stage fluctuated more than 13 feet and the lake surface area receded and expanded from 96 acres to 148 acres over drier and wetter years that included hurricanes, two El Nino events and a La Nina event. The recently developed Unsaturated Zone Flow (UZF1) and Lake (LAK7) packages for MODFLOW-2005 were used to simulate the changing lake sizes and the extent of the groundwater catchment contributing flow to the lake. The lake area was discretized to occupy the largest surface area at the highest observed stage and then allowed to change size. Lake cells convert to land cells and receive infiltration as receding lake area exposes the underlying unsaturated zone to rainfall and recharge. The unique model conceptualization also made it possible to capture the dynamic size of the groundwater catchment contributing to lake inflows, as the surface area and volume of the lake changed during the study

  20. A Review of Thorium Utilization as an option for Advanced Fuel Cycle--Potential Option for Brazil in the Future

    SciTech Connect

    Maiorino, J.R.; Carluccio, T.

    2004-10-03

    Since the beginning of Nuclear Energy Development, Thorium was considered as a potential fuel, mainly due to the potential to produce fissile uranium 233. Several Th/U fuel cycles, using thermal and fast reactors were proposed, such as the Radkwoski once through fuel cycle for PWR and VVER, the thorium fuel cycles for CANDU Reactors, the utilization in Molten Salt Reactors, the utilization of thorium in thermal (AHWR), and fast reactors (FBTR) in India, and more recently in innovative reactors, mainly Accelerator Driven System, in a double strata fuel cycle. All these concepts besides the increase in natural nuclear resources are justified by non proliferation issues (plutonium constrain) and the waste radiological toxicity reduction. The paper intended to summarize these developments, with an emphasis in the Th/U double strata fuel cycle using ADS. Brazil has one of the biggest natural reserves of thorium, estimated in 1.2 millions of tons of ThO{sub 2}, as will be reviewed in this paper, and therefore R&D programs would be of strategically national interest. In fact, in the past there was some projects to utilize Thorium in Reactors, as the ''Instinto/Toruna'' Project, in cooperation with France, to utilize Thorium in Pressurized Heavy Water Reactor, in the mid of sixties to mid of seventies, and the thorium utilization in PWR, in cooperation with German, from 1979-1988. The paper will review these initiatives in Brazil, and will propose to continue in Brazil activities related with Th/U fuel cycle.

  1. Restricted daytime feeding attenuates reentrainment of the circadian melatonin rhythm after an 8-h phase advance of the light-dark cycle.

    PubMed

    Kalsbeek, A; Barassin, S; van Heerikhuize, J J; van der Vliet, J; Buijs, R M

    2000-02-01

    It is well established that in the absence of photic cues, the circadian rhythms of rodents can be readily phase-shifted and entrained by various nonphotic stimuli that induce increased levels of locomotor activity (i.e., benzodiazepines, a new running wheel, and limited food access). In the presence of an entraining light-dark (LD) cycle, however, the entraining effects of nonphotic stimuli on (parts of) the circadian oscillator are far less clear. Yet, an interesting finding is that appropriately timed exercise after a phase shift can accelerate the entrainment of circadian rhythms to the new LD cycle in both rodents and humans. The present study investigated whether restricted daytime feeding (RF) (1) induces a phase shift of the melatonin rhythm under entrained LD conditions and (2) accelerates resynchronization of circadian rhythms after an 8-h phase advance. Animals were adapted to RF with 2-h food access at the projected time of the new dark onset. Before and at several time points after the 8-h phase advance, nocturnal melatonin profiles were measured in RF animals and animals on ad libitum feeding (AL). In LD-entrained conditions, RF did not cause any significant changes in the nocturnal melatonin profile as compared to AL. Unexpectedly, after the 8-h phase advance, RF animals resynchronized more slowly to the new LD cycle than AL animals. These results indicate that prior entrainment to a nonphotic stimulus such as RF may "phase lock" the circadian oscillator and in that way hinder resynchronization after a phase shift. PMID:10677017

  2. Rapid phase adjustment of melatonin and core body temperature rhythms following a 6-h advance of the light/dark cycle in the horse

    PubMed Central

    Murphy, Barbara A; Elliott, Jeffrey A; Sessions, Dawn R; Vick, Mandi M; Kennedy, Erin L; Fitzgerald, Barry P

    2007-01-01

    Background Rapid displacement across multiple time zones results in a conflict between the new cycle of light and dark and the previously entrained program of the internal circadian clock, a phenomenon known as jet lag. In humans, jet lag is often characterized by malaise, appetite loss, fatigue, disturbed sleep and performance deficit, the consequences of which are of particular concern to athletes hoping to perform optimally at an international destination. As a species renowned for its capacity for athletic performance, the consequences of jet lag are also relevant for the horse. However, the duration and severity of jet lag related circadian disruption is presently unknown in this species. We investigated the rates of re-entrainment of serum melatonin and core body temperature (BT) rhythms following an abrupt 6-h phase advance of the LD cycle in the horse. Methods Six healthy, 2 yr old mares entrained to a 12 h light/12 h dark (LD 12:12) natural photoperiod were housed in a light-proofed barn under a lighting schedule that mimicked the external LD cycle. Following baseline sampling on Day 0, an advance shift of the LD cycle was accomplished by ending the subsequent dark period 6 h early. Blood sampling for serum melatonin analysis and BT readings were taken at 3-h intervals for 24 h on alternate days for 11 days. Disturbances to the subsequent melatonin and BT 24-h rhythms were assessed using repeated measures ANOVA and analysis of Cosine curve fitting parameters. Results We demonstrate that the equine melatonin rhythm re-entrains rapidly to a 6-h phase advance of an LD12:12 photocycle. The phase shift in melatonin was fully complete on the first day of the new schedule and rhythm phase and waveform were stable thereafter. In comparison, the advance in the BT rhythm was achieved by the third day, however BT rhythm waveform, especially its mesor, was altered for many days following the LD shift. Conclusion Aside from the temperature rhythm disruption, rapid

  3. Ten years' experience with four cycles of bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone, procarbazine (BEACOPP)-escalated followed by four cycles of baseline-dose BEACOPP in patients with advanced stage Hodgkin lymphoma: a single-center, retrospective study.

    PubMed

    Belada, David; Štěpánková, Pavla; Sýkorová, Alice; Žák, Pavel; Smolej, Lukáš

    2015-07-01

    The HD-9 trial showed that eight cycles of BEACOPP (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone, procarbazine)-escalated led to significant improvements in response rate, progression-free survival and overall survival over COPP/ABVD (cyclophosphamide, vincristine, prednisone, procarbazine/doxorubicin, bleomycin, vinblastine, dacarbazine) therapy. This monocentric retrospective study was performed to evaluate 10 years of experience with four cycles of BEACOPP-escalated and four cycles of BEACOPP-baseline outside of clinical trials. The outcomes were assessed in 78 patients with newly diagnosed advanced stage Hodgkin lymphoma. A complete response after chemotherapy ± radiotherapy was achieved in 75 patients (96%). At the median follow-up of 74 months, the actuarial 5- and 10-year freedom from treatment failure (FFTF) rates were 91% and 89%, and actuarial 5- and 10-year overall survival rates for the entire group were 93% and 90%, respectively. These results suggest that the combination of escalated and baseline BEACOPP chemotherapy is feasible in routine practice with good efficacy and acceptable toxicity. PMID:25330440

  4. Can a variable alpha induce limit cycle behavior and exponential luminosity decay in transient soft x ray sources?

    NASA Technical Reports Server (NTRS)

    Meirellesfilho, C.; Liang, Edison P.

    1994-01-01

    There has been, recently, a revival of the stability problem of accretion disks. Much of this renewed interest is due to recent observational data on transient soft X-ray novae, which are low-mass X-ray binaries. It is widely believed that nonsteady mass transfer from the secondary onto the compact primary, through an accretion disk, is the reason for the observed spectacular events in the form of often repetitive outbursts, with recurrence times ranging from 1 to 60 yr and duration time on the scale of months. Though not having reached yet a consensus about the nature of the mechanism that regulates the mass transfer, the disk thermal instability model seems to be favored by the fact that the rise in the hard X-ray luminosity is prior to the rise in the soft X-ray luminosity, while the mass transfer instability model seems to be hindered by the fact that the luminosity during quiescence is unable to trigger the thermal instability. However, it should be stressed that, remarkably, the X-ray light curves of these X-ray novae all show overall exponential decays, a feature quite difficult to reproduce in the framework of the viscous disk model, which yields powerlike luminosity decay. Taking into account this observational constraint, we have studied the temporal evolution of perturbations in the accretion rate, under the assumption that alpha is radial and parameter dependent. The chosen dependence is such that the model can reproduce limit cycle behavior (the system is locally unstable but globally stable). However, the kind of dependence we are looking for in alpha does not allow us to use the usual Shakura and Sunyaev procedure in the sense that we no longer can obtain a linearized continuity equation without explicit dependence on the accretion rate. This is so because now we cannot eliminate the accretion rate by using the angular momentum conservation equation.

  5. T-R Cycle Characterization and Imaging: Advanced Diagnostic Methodology for Petroleum Reservoir and Trap Detection and Delineation

    SciTech Connect

    Ernest A. Mancini

    2006-08-30

    Characterization of stratigraphic sequences (T-R cycles or sequences) included outcrop studies, well log analysis and seismic reflection interpretation. These studies were performed by researchers at the University of Alabama, Wichita State University and McGill University. The outcrop, well log and seismic characterization studies were used to develop a depositional sequence model, a T-R cycle (sequence) model, and a sequence stratigraphy predictive model. The sequence stratigraphy predictive model developed in this study is based primarily on the modified T-R cycle (sequence) model. The T-R cycle (sequence) model using transgressive and regressive systems tracts and aggrading, backstepping, and infilling intervals or sections was found to be the most appropriate sequence stratigraphy model for the strata in the onshore interior salt basins of the Gulf of Mexico to improve petroleum stratigraphic trap and specific reservoir facies imaging, detection and delineation. The known petroleum reservoirs of the Mississippi Interior and North Louisiana Salt Basins were classified using T-R cycle (sequence) terminology. The transgressive backstepping reservoirs have been the most productive of oil, and the transgressive backstepping and regressive infilling reservoirs have been the most productive of gas. Exploration strategies were formulated using the sequence stratigraphy predictive model and the classification of the known petroleum reservoirs utilizing T-R cycle (sequence) terminology. The well log signatures and seismic reflector patterns were determined to be distinctive for the aggrading, backstepping and infilling sections of the T-R cycle (sequence) and as such, well log and seismic data are useful for recognizing and defining potential reservoir facies. The use of the sequence stratigraphy predictive model, in combination with the knowledge of how the distinctive characteristics of the T-R system tracts and their subdivisions are expressed in well log patterns

  6. The Measurement of the Solar Spectral Irradiance Variability at 782 nm during the Solar Cycle 24 using the SES on-board PICARD

    NASA Astrophysics Data System (ADS)

    Meftah, Mustapha; Hauchecorne, Alain; Irbah, Abdanour; Bekki, Slimane

    2016-04-01

    A Sun Ecartometry Sensor (SES) was developed to provide the stringent pointing requirements of the PICARD satellite. The SES sensor produced an image of the Sun at 782+/-5 nm. From the SES data, we obtained a new time series of the solar spectral irradiance at 782nm from 2010 to 2014. SES observations provided a qualitatively consistent evolution of the solar spectral irradiance variability at 782 nm during the solar cycle 24. Comparisons will be made with Spectral And Total Irradiance REconstruction for the Satellite era (SATIRE-S) semi-empirical model and with the Spectral Irradiance Monitor instrument (SIM) on-board the Solar Radiation and Climate Experiment satellite (SORCE). These data will help to improve the representation of the solar forcing in the IPSL Global Circulation Model.

  7. Intraannual cycles of NMVOCs in the tropical troposphere and their use for interpreting seasonal variability in CO

    NASA Astrophysics Data System (ADS)

    Read, K.; Carpenter, L.; Lewis, A.; Lee, J.; Neves, L.; Faria, B.

    2009-04-01

    18 month's data of non-methane volatile organic compound (NMVOC) and carbon monoxide (CO) concentrations obtained from the Cape Verde Atmospheric Observatory (Observatório Atmosferico de Cabo Verde: Humberto Duarte Fonseca CVAO, 16,848°N, 24.871°W) in the tropical Atlantic Ocean are presented here. The CO measurements demonstrate the expected sinusoidal curve driven by its loss reaction with OH, but with a smaller amplitude than modelling studies would suggest for this region. Simultaneous ethane measurements were used to derive the seasonal variation in the "nominal hydroxyl radical (OH) concentration (n[OH])" experienced along the air mass trajectory of ethane, by assuming a fixed ethane emission rate. The n[OH] represents the variability in OH concentration assuming there are no intraannual changes in ethane emissions, and was subsequently used to create seasonal fits of CO concentrations, allowing interpretation of differing sources and sinks from those of ethane. Deviation of the measured CO concentrations from their "n[OH] fit" indicates that summer sources of CO are approximately 60% higher than winter, assuming that ethane is not lost through reactions with chlorine or bromine atoms. Evidence suggests that the production of CO from the oxidation of CH4 and NMVOC and in particular from methanol, acetone and acetaldehyde (from both terrestrial and oceanic sources) is increased in this region in summer and this could be an explanation for the observations. Other NMVOC measurements are presented here as indicators of potential conflicting halogen chemistry and of alternative emission sources. Longer-term measurements of NMVOC and CO, such as those presented in this paper, are essential for our understanding of the oxidation capacity, atmospheric processes and composition of the atmosphere.

  8. Unraveling the Drivers of Spatial and Temporal Variability in Biogeochemical Cycling at Aquifer-River Interfaces - The LEVERHULME Hyporheic Zone Research Network

    NASA Astrophysics Data System (ADS)

    Krause, Stefan

    2015-04-01

    While there has been substantial improvement of understanding hyporheic exchange flow and residence time controls on biogeochemical turnover rates, there is little knowledge of the actual drivers of the spatial and temporal variability of interlinked biogeochemical cycles. Previous research has mainly focused on bedform controlled hyporheic exchange and the transformation of surface solutes along a hyporheic flow path but failed to explain observations of spatially and temporally variable nutrient turnover in streambeds with higher structural heterogeneity and autochthonous carbon and nitrogen sources. The "Leverhulme Hyporheic Zone Research Network" has developed an interdisciplinary strategy for investigating the physical controls on hyporheic exchange fluxes and residence time distributions, heat and reactive solute transport along biogeographical and catchment gradients. This strategy combines smart tracer applications with distributed sensor networks in multi-scale nested monitoring schemes and numerical model studies to investigate the interactions between physico-chemical process dynamics and hyporheic microbial, invertebrate and macrophyte ecology. Investigations integrating the process knowledge from mesocosms to artificial channels and stream reaches highlight the impact of small-scale streambed structure on spatial patterns of hyporheic exchange flow, residence time distribution and the development of biogeochemical hotspots. Manipulation studies inhibiting flow through dominant hyporheic exchange flow paths allowed to quantify the functional significance, sensitivity and resilience of biogeochemical, microbial and ecological functioning of identified hyporheic hotspots to environmental change. Further discharge and stage manipulations proved to not only control in-channel macrophyte growth but also temperature patterns and residence time distributions as well as microbial metabolic activity and biogeochemical processing rates, highlighting the potential

  9. Unraveling the Drivers of Spatial and Temporal Variability in Biogeochemical Cycling at Aquifer-River Interfaces - The LEVERHULME Hyporheic Zone Research Network

    NASA Astrophysics Data System (ADS)

    Krause, S.; Ward, A. S.; Zarnetske, J. P.; Martí Roca, E.; Larned, S.; Milner, A.; Datry, T.; Fleckenstein, J. H.; Schmidt, C.; Blaen, P.; Kurz, M. J.; Klaar, M. J.; Drummond, J. D.; Knapp, J.; Folegot, S.; Hannah, D. M.; Romeijn, P.; Blume, T.; Lewandowski, J.; Maruedo, A.; Ledger, M.; Lee-Cullin, J. A.; O'Callaghan, M.; Keller, T.; Vieweg, M.

    2014-12-01

    While there has been substantial improvement of understanding hyporheic exchange flow and residence time controls on biogeochemical turnover rates, there is little knowledge of the actual drivers of the spatial and temporal variability of interlinked biogeochemical cycles. Previous research has mainly focused on bedform controlled hyporheic exchange and the transformation of surface solutes along a hyporheic flow path but failed to explain observations of spatially and temporally variable nutrient turnover in streambeds with higher structural heterogeneity and autochthonous carbon and nitrogen sources. The "Leverhulme Hyporheic Zone Research Network" has developed an interdisciplinary strategy for investigating the physical controls on hyporheic exchange fluxes and residence time distributions, heat and reactive solute transport along biogeographical and catchment gradients. This strategy combines smart tracer applications with distributed sensor networks in multi-scale nested monitoring schemes and numerical model studies to investigate the interactions between physico-chemical process dynamics and hyporheic microbial, invertebrate and macrophyte ecology. Investigations integrating the process knowledge from mesocosms to artificial channels and stream reaches highlight the impact of small-scale streambed structure on spatial patterns of hyporheic exchange flow, residence time distribution and the development of biogeochemical hotspots. Manipulation studies inhibiting flow through dominant hyporheic exchange flow paths allowed to quantify the functional significance, sensitivity and resilience of biogeochemical, microbial and ecological functioning of identified hyporheic hotspots to environmental change. Further discharge and stage manipulations proved to not only control in-channel macrophyte growth but also temperature patterns and residence time distributions as well as microbial metabolic activity and biogeochemical processing rates, highlighting the potential

  10. T-R CYCLE CHARACTERIZATION AND IMAGING: ADVANCED DIAGNOSTIC METHODOLOGY FOR PETROLEUM RESERVOIR AND TRAP DETECTION AND DELINEATION

    SciTech Connect

    Ernest A. Mancini

    2005-06-01

    The principal research effort for Year 2 of the project is on stratigraphic model assessment and development. The research focus for the first six (6) months of Year 2 is on T-R cycle model development. The emphasis for the remainder of the year is on assessing the depositional model and developing a sequence stratigraphy model. Outcrop study and data integration will continue throughout Year 2.

  11. Fluidized-bed technology enabling the integration of high temperature solar receiver CSP systems with steam and advanced power cycles

    DOE PAGESBeta

    Sakadjian, B.; Hu, S.; Maryamchik, M.; Flynn, T.; Santelmann, K.; Ma, Z.

    2015-06-05

    Solar Particle Receivers (SPR) are under development to drive concentrating solar plants (CSP) towards higher operating temperatures to support higher efficiency power conversion cycles. The novel high temperature SPR-based CSP system uses solid particles as the heat transfer medium (HTM) in place of the more conventional fluids such as molten salt or steam used in current state-of-the-art CSP plants. The solar particle receiver (SPR) is designed to heat the HTM to temperatures of 800 °C or higher which is well above the operating temperatures of nitrate-based molten salt thermal energy storage (TES) systems. The solid particles also help overcome somemore » of the other challenges associated with molten salt-based systems such as freezing, instability and degradation. The higher operating temperatures and use of low cost HTM and higher efficiency power cycles are geared towards reducing costs associated with CSP systems. This paper describes the SPR-based CSP system with a focus on the fluidized-bed (FB) heat exchanger and its integration with various power cycles. Furthermore, the SPR technology provides a potential pathway to achieving the levelized cost of electricity (LCOE) target of $0.06/kWh that has been set by the U.S. Department of Energy's SunShot initiative.« less

  12. Fluidized-bed technology enabling the integration of high temperature solar receiver CSP systems with steam and advanced power cycles

    SciTech Connect

    Sakadjian, B.; Hu, S.; Maryamchik, M.; Flynn, T.; Santelmann, K.; Ma, Z.

    2015-06-05

    Solar Particle Receivers (SPR) are under development to drive concentrating solar plants (CSP) towards higher operating temperatures to support higher efficiency power conversion cycles. The novel high temperature SPR-based CSP system uses solid particles as the heat transfer medium (HTM) in place of the more conventional fluids such as molten salt or steam used in current state-of-the-art CSP plants. The solar particle receiver (SPR) is designed to heat the HTM to temperatures of 800 °C or higher which is well above the operating temperatures of nitrate-based molten salt thermal energy storage (TES) systems. The solid particles also help overcome some of the other challenges associated with molten salt-based systems such as freezing, instability and degradation. The higher operating temperatures and use of low cost HTM and higher efficiency power cycles are geared towards reducing costs associated with CSP systems. This paper describes the SPR-based CSP system with a focus on the fluidized-bed (FB) heat exchanger and its integration with various power cycles. Furthermore, the SPR technology provides a potential pathway to achieving the levelized cost of electricity (LCOE) target of $0.06/kWh that has been set by the U.S. Department of Energy's SunShot initiative.

  13. Report on the workshop "Decay spectroscopy at CARIBU: advanced fuel cycle applications, nuclear structure and astrophysics". 14-16 April 2011, Argonne National Laboratory, USA.

    SciTech Connect

    Kondev, F.; Carpenter, M.P.; Chowdhury, P.; Clark, J.A.; Lister, C.J.; Nichols, A.L.; Swewryniak, D.

    2011-10-06

    A workshop on 'Decay Spectroscopy at CARIBU: Advanced Fuel Cycle Applications, Nuclear Structure and Astrophysics' will be held at Argonne National Laboratory on April 14-16, 2011. The aim of the workshop is to discuss opportunities for decay studies at the Californium Rare Isotope Breeder Upgrade (CARIBU) of the ATLAS facility with emphasis on advanced fuel cycle (AFC) applications, nuclear structure and astrophysics research. The workshop will consist of review and contributed talks. Presentations by members of the local groups, outlining the status of relevant in-house projects and availabile equipment, will also be organized. time will also be set aside to discuss and develop working collaborations for future decay studies at CARIBU. Topics of interest include: (1) Decay data of relevance to AFC applications with emphasis on reactor decay heat; (2) Discrete high-resolution gamma-ray spectroscopy following radioactive decya and related topics; (3) Calorimetric studies of neutron-rich fission framgents using Total ABsorption Gamma-Ray Spectrometry (TAGS) technique; (4) Beta-delayed neutron emissions and related topics; and (5) Decay data needs for nuclear astrophysics.

  14. Explaining streamflow variability of the Gila and Rio Grande rivers : Pacific teleconnections and catchment-scale interaction of the hydrological cycle with vegetation and soil moisture

    NASA Astrophysics Data System (ADS)

    Pascolini-Campbell, M.; Seager, R.

    2015-12-01

    The streamflows of the Gila River, N.M. and the upper Rio Grande, with headwaters in Colorado are influenced by a range of drivers including the El Nino-Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), the Atlantic Multidecadal Oscillation (AMO) and, for the Gila, the North American Monsoon. At the catchment scale, runoff to the river is modulated by the interaction of snowmelt, rainfall, evapotranspiration, soil moisture and vegetation. A simple eco-hydological model is used to explain the seasonal cycles of flow of the Gila (strong spring peak, weak summer peak) and upper Rio Grande (single spring peak) in terms of precipitation, snowpack, and evapotranspiration. We then examine the drivers of streamflow variability using USGS gages located upstream of human extraction, precipitation and temperature data from PRISM, and SST data from ERSST. High spring streamflow tends to occur in response to prior winter El Nino but not all high and low streamflow events can be explained by the Pacific teleconnection. Decadal variations, including low flows in the Gila and upper Rio Grande since the mid 1990s, are explained in terms of the Pacific and Atlantic Ocean decadal variability.

  15. Some Investigations on Hardness of Investment Casting Process After Advancements in Shell Moulding for Reduction in Cycle Time

    NASA Astrophysics Data System (ADS)

    Singh, R.; Mahajan, V.

    2014-07-01

    In the present work surface hardness investigations have been made on acrylonitrile butadiene styrene (ABS) pattern based investment castings after advancements in shell moulding for replication of biomedical implants. For the present study, a hip joint, made of ABS material, was fabricated as a master pattern by fused deposition modelling (FDM). After preparation of master pattern, mold was prepared by deposition of primary (1°), secondary (2°) and tertiary (3°) coatings with the addition of nylon fibre (1-2 cm in length of 1.5D). This study outlines the surface hardness mechanism for cast component prepared from ABS master pattern after advancement in shell moulding. The results of study highlight that during shell production, fibre modified shells have a much reduced drain time. Further the results are supported by cooling rate and micro structure analysis of casting.

  16. T-R Cycle Characterization and Imaging: Advanced Diagnostic Methodology for Petroleum Reservoir and Trap Detection and Delineation

    SciTech Connect

    Ernest A. Mancini; William C. Parcell; Bruce S. Hart

    2005-09-19

    The principal research effort for Year 2 of the project is on stratigraphic model assessment and development. The research focus for the first six (6) months of Year 2 is on T-R cycle model development. The emphasis for the remainder of the year is on assessing the depositional model and developing and testing a sequence stratigraphy model. The development and testing of the sequence stratigraphy model has been accomplished through integrated outcrop, well log and seismic studies of Mesozoic strata in the Gulf of Mexico, North Atlantic and Rocky Mountain areas.

  17. Advances in understanding the genesis and evolution solar energetic particle events over the last two solar cycles

    NASA Astrophysics Data System (ADS)

    Vainio, Rami

    2016-04-01

    I will review the observational and modeling efforts related to solar energetic particle (SEP) events over the 23rd and 24th solar cycles. I will concentrate on large SEP events related to coronal mass ejections (CMEs), but discuss observations related to the possible role of flares in the acceleration of particles in those events, as well. The possible roles of various acceleration and transport processes in understanding the characteristics of the events will be discussed. This work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 637324 (HESPERIA).

  18. Reactor applications of the Compact Fusion Advanced Rankine (CFAR) cycle for a D-T tokamak fusion reactor

    NASA Astrophysics Data System (ADS)

    Hoffman, H. A.; Logan, B. G.; Campbell, R. B.

    1988-03-01

    A preliminary design of a D-T fusion reactor blanket and MHD power conversion system is made based on the CFAR concept, and it was found that performance and costs for the reference cycle are very attractive. While much remains to be done, the potential advantage of liquid metal Rankine cycles for fusion applications are much clearer now. These include low pressures and mass flow rates, a nearly isothermal module shell which minimizes problems of thermal distortion and stresses, and an insensitivity to pressure losses in the blanket so that the two-phase MHD pressure drops in the boiling part of the blanket and the ordinary vapor pressure drops in the pebble-bed superheating zones are acceptable (the direct result of pumping a liquid rather than having to compress a gas). There are no moving parts in the high-temperature MHD power generators, no steam bottoming plant is required, only small vapor precoolers and condensers are needed because of the high heat rejection temperatures, and only a relatively small natural-draft heat exchanger is required to reject the heat to the atmosphere. The net result is a very compact fusion reactor and power conversion system which fit entirely inside an 18 meter radius reactor vault. Although a cost analysis has not yet been performed, preliminary cost estimates indicate low capital costs and a very attractive cost of electricity.

  19. Expression of cell cycle markers is predictive of the response to primary systemic therapy of locally advanced breast cancer.

    PubMed

    Tőkés, Tímea; Tőkés, Anna-Mária; Szentmártoni, Gyöngyvér; Kiszner, Gergő; Madaras, Lilla; Kulka, Janina; Krenács, Tibor; Dank, Magdolna

    2016-06-01

    We aimed to analyze to what extent expression of four cell cycle regulation markers-minichromosome maintenance protein (MCM2), Ki-67, cyclin A, and phosphohistone-H3 (PHH3)-predict response to primary systemic therapy in terms of pathological complete remission (pCR). In search of an accurate and reproducible scoring method, we compared computer-assisted (CA) and routine visual assessment (VA) of immunoreactivity. We included 57 patients with breast cancer in the study. The cell cycle markers were detected using immunohistochemistry on pre-therapy core biopsy samples. Parallel CA (validated by manual labeling) and standard VA were performed and compared for diagnostic agreement and predictive value for pCR. CA and VA results were dichotomized based on receiver operating characteristic analysis defined optimal cut-off values. "High" was defined by staining scores above the optimal cut-off, while "low" had staining scores below the optimal cut-off. The CA method resulted in significantly lower values for Ki-67 and MCM2 compared to VA (mean difference, -3.939 and -4.323). Diagnostic agreement was highest for cyclin A and PHH3 (-0.586 and -0.666, respectively). Regardless of the method (CA/VA) used, all tested markers were predictive of pCR. Optimal cut-off-based dichotomization improved diagnostic agreement between the CA and VA methods for every marker, in particular for MCM2 (κ = 1, p < 0.000). Cyclin A displayed excellent agreement (κ = 0.925; p < 0.000), while Ki-67 and PHH3 showed good agreement (κ = 0.789, p < 0.000 and κ = 0.794, p < 0.000, respectively). We found all cell cycle markers (Ki-67, MCM2, cyclin A, and PHH3) predictive of pCR. Diagnostic agreement between CA and VA was better at lower staining scores but improved after optimal cut-off-based dichotomization. PMID:27026269

  20. South China Sea Surface Waters During the Late Pleistocene: Records of the Relationship Between South East Asian Monsoon Variability and Glacial-Interglacial Cycles

    NASA Astrophysics Data System (ADS)

    McIntyre, K.; Oppo, D.

    2001-05-01

    One of the major goals of Ocean Drilling Program Leg 184 in the South China Sea was to recover sediment records that could be used to examine the history of the South East Asian monsoon relative to external variation in the global climate, on both orbital and millennial timescales. Examinations of how monsoonal variability in this region interacts with larger changes in global climate speak to the ongoing debate about the role of the tropical and equatorial regions in climate change. In order to reconstruct this interaction we have generated a new 700 kyr record of planktonic foraminiferal (G. ruber) oxygen and carbon isotopes from Ocean Drilling Program site 1145 in the South China Sea (19° 35.04'N, 117° 37.86'E, 3175 m. water depth). The oxygen isotope record reflects both global ice volume and a composite of sea surface salinity and temperature that varies in response to monsoonally driven changes in sea surface circulation and regional precipitation. The carbon isotopic record reflects changes in local productivity and global changes in the carbon budget. Since our record has both a strong 100-kyr glacial component and a strong precessional component, it allows us to examine the interaction between high-latitude glacial influence and local precessional influence on the South East Asian monsoon. As seen at other sites in the South China Sea, there is an overall increase in sedimentation rates coming toward the present. Sedimentation rates at this site decrease threefold at 400 Ka, with sedimentation rates ~6 cm/kyr prior to this time and rates of ~20 cm/kyr after. As a consequence, temporal resolution for the latter part of the record varies between 400 and 1000 years, and is >2000 years before 400 ka. We find that sub-Milankovitch variability in both oxygen and carbon isotopes is consistently high throughout glacial-interglacial cycles, +/-0.6 ‰ in δ 18O and +/-0.4 ‰ in δ 13C. Over the last 400 kyrs we find both variability on 3-4 kyr timescales and on

  1. High-temperature, low-cycle fatigue of advanced copper-base alloys for rocket nozzles. Part 1: Narloy Z

    NASA Technical Reports Server (NTRS)

    Conway, J. B.; Stentz, R. H.; Berling, J. T.

    1974-01-01

    Short-term tensile and low-cycle fatigue data are reported for Narloy Z, a centrifugally cast, copper-base alloy. Tensile tests were performed at room temperature in air and in argon at 482, 538 and 593 C using an axial strain rate of .002/sec to the -1 power. In addition tensile tests were performed at 538 C in an evaluation of tensile properties at strain rates of .004 and .01/sec to the -1 power. Ultimate and yield strength values of about 315 and 200 MN/sq m respectively were recorded at room temperature and these decreased to about 120 and 105 respectively as the temperature was increased to 593 C. Reduction in area values were recorded in the range from 40 to 50% with some indication of a minimum ductility point at 538 C.

  2. The Advanced Learner's Sociolinguistic Profile: On Issues of Individual Differences, Second Language Exposure Conditions, and Type of Sociolinguistic Variable

    ERIC Educational Resources Information Center

    Howard, Martin

    2012-01-01

    Situated within the recent new wave of second language acquisition studies investigating the acquisition of sociolinguistic variation, this article draws on a longitudinal database of advanced French interlanguage to explore a number of issues that have not yet been extensively investigated. They concern the issue of individual variation in the…

  3. Nutrient cycling.

    PubMed

    Bormann, F H; Likens, G E

    1967-01-27

    The small-watershed approach to problems of nutrient cycling has these advantages. (i) The small watershed is a natural unit of suitable size for intensive study of nutrient cycling at the ecosystem level. (ii) It provides a means of reducing to a minimum, or virtually eliminating, the effect of the difficult-to-measure variables of geologic input and nutrient losses in deep seepage. Control of these variables makes possible accurate measurement of nutrient input and output (erosion) and therefore establishes the relationship of the smaller ecosystem to the larger biospheric cycles. (iii) The small-watershed approach provides a method whereby such important parameters as nutrient release from minerals (weathering) and annual nutrient budgets may be calculated. (iv) It provides a means of studying the interrelationships between the biota and the hydrologic cycle, various nutrient cycles, and energy flow in a single system. (v) Finally, with the small-watershed system we can test the effect of various land-management practices or environmental pollutants on nutrient cycling in natural systems. PMID:17737551

  4. Solar Cycle 23: An Anomalous Cycle?

    NASA Astrophysics Data System (ADS)

    de Toma, G.; White, O. R.; Chapman, G. A.; Walton, S. R.; Preminger, D. G.; Cookson, A. M.

    2004-05-01

    We discuss the importance of solar cycle 23 as a magnetically simpler cycle and a variant from recent cycles. We see a significant decrease in sunspot activity in cycle 23 relative to cycle 22, but the strength of the total solar irradiance (TSI) cycle did not change significantly. The latest SOHO/VIRGO TSI time series is analyzed using new solar variability measures obtained from full-disk solar images made at the San Fernando Observatory and the MgII 280nm index. The TSI record for the period 1986 to the present is reproduced within about 130ppm RMS using only two indices representing photospheric and chromospheric sources of variability due to magnetic regions. This is in spite of the difference in magnetic activity between the two cycles. Our results show the continuing improvement in TSI measurements and surrogates containing information necessary to account for irradiance variability.

  5. Development of advanced process-based model towards evaluation of boundless biogeochemical cycles in terrestrial-aquatic continuum

    NASA Astrophysics Data System (ADS)

    Nakayama, Tadanobu; Maksyutov, Shamil

    2014-05-01

    Recent research shows inland water may play some role in continental biogeochemical cycling though its contribution has remained uncertain due to a paucity of data (Battin et al. 2009). The author has developed process-based National Integrated Catchment-based Eco-hydrology (NICE) model (Nakayama, 2008a-b, 2010, 2011a-b, 2012a-c, 2013; Nakayama and Fujita, 2010; Nakayama and Hashimoto, 2011; Nakayama and Shankman, 2013a-b; Nakayama and Watanabe, 2004, 2006, 2008a-b; Nakayama et al., 2006, 2007, 2010, 2012), which incorporates surface-groundwater interactions, includes up- and down-scaling processes between local, regional and global scales, and can simulate iteratively nonlinear feedback between hydrologic, geomorphic, and ecological processes. In this study, NICE was extended to evaluate global hydrologic cycle by using various global datasets. The simulated result agreed reasonably with that in the previous research (Fan et al., 2013) and extended to clarify further eco-hydrological process in global scale. Then, NICE was further developed to incorporate the biogeochemical cycle including the reaction between inorganic and organic carbons (DOC, POC, DIC, pCO2, etc.) in the biosphere (terrestrial and aquatic ecosystems including surface water and groundwater). The model simulated the carbon cycle, for example, CO2 evasion from inland water in global scale, which is relatively in good agreement in that estimated by empirical relation using the previous pCO2 data (Aufdenkampe et al., 2011; Global River Chemistry Database, 2013). This simulation system would play important role in identification of full greenhouse gas balance of the biosphere and spatio-temporal hot spots in boundless biogeochemical cycle (Cole et al. 2007; Frei et al. 2012). References; Aufdenkampe, A.K., et al., Front. Ecol. Environ., doi:10.1890/100014, 2011. Battin, T.J., et al., Nat. Geosci., 2, 598-600, 2009. Cole, J.J. et al., Ecosystems, doi:10.1007/s10021-006-9013-8, 2007. Fan, Y. et al

  6. Sustainability Efficiency Factor: Measuring Sustainability in Advanced Energy Systems through Exergy, Exergoeconomic, Life Cycle, and Economic Analyses

    NASA Astrophysics Data System (ADS)

    Boldon, Lauren

    The Encyclopedia of Life Support Systems defines sustainability or industrial ecology as "the wise use of resources through critical attention to policy, social, economic, technological, and ecological management of natural and human engineered capital so as to promote innovations that assure a higher degree of human needs fulfilment, or life support, across all regions of the world, while at the same time ensuring intergenerational equity" (Encyclopedia of Life Support Systems 1998). Developing and integrating sustainable energy systems to meet growing energy demands is a daunting task. Although the technology to utilize renewable energies is well understood, there are limited locations which are ideally suited for renewable energy development. Even in areas with significant wind or solar availability, backup or redundant energy supplies are still required during periods of low renewable generation. This is precisely why it would be difficult to make the switch directly from fossil fuel to renewable energy generation. A transition period in which a base-load generation supports renewables is required, and nuclear energy suits this need well with its limited life cycle emissions and fuel price stability. Sustainability is achieved by balancing environmental, economic, and social considerations, such that energy is produced without detriment to future generations through loss of resources, harm to the environment, etcetera. In essence, the goal is to provide future generations with the same opportunities to produce energy that the current generation has. This research explores sustainability metrics as they apply to a small modular reactor (SMR)-hydrogen production plant coupled with wind energy and storage technologies to develop a new quantitative sustainability metric, the Sustainability Efficiency Factor (SEF), for comparison of energy systems. The SEF incorporates the three fundamental aspects of sustainability and provides SMR or nuclear hybrid energy system

  7. Effects of an advanced temperature cycle on smolt development and endocrinology indicate that temperature is not a zeitgeber for smolting in Atlantic salmon

    USGS Publications Warehouse

    McCormick, S.D.; Shrimpton, J.M.; Moriyama, S.; Bjornsson, Bjorn Thrandur

    2002-01-01

    Atlantic salmon (Salmo salar) juveniles were reared under simulated conditions of normal photoperiod (LDN) or short days (LD 9:15) and ambient temperature (AMB: normal temperature increases in April) or an advanced temperature cycle (ADV: temperature increases in February). Under both photoperiod conditions, the timing of increased and peak levels of gill Na+,K+-ATPase activity were not altered by temperature, although the rate of increase was initially greater under ADV. ADV/LD 9:15 resulted in peak gill Na+,K+-ATPase activity that was half of that seen under normal photoperiod and temperature conditions. Plasma growth hormone (GH) levels increased threefold in late March under ADV/LDN, but not under ADV/LD 9:15, indicating that there is a photoperiod-dependent effect of temperature on levels of this hormone. Plasma insulin-like growth factor I (IGF-I) increased in spring in all groups, with increases occurring significantly earlier in the ADV/LDN group. In each photoperiod condition, the advanced temperature cycle resulted in large decreases in plasma thyroxine (T4) levels in March, which subsequently recovered, whereas plasma 3,5,3???-triiodo-L-thyronine (T3) levels were not substantially affected by either photoperiod or temperature. There was no consistent pattern of change in plasma cortisol levels. The results do not provide support for the role of temperature as a zeitgeber, but do indicate that temperature has a role in the timing of smolting by affecting the rate of development and interacting with the photoperiod.

  8. The relationship between an inflammation‐based prognostic score (Glasgow Prognostic Score) and changes in serum biochemical variables in patients with advanced lung and gastrointestinal cancer

    PubMed Central

    Brown, D J F; Milroy, R; Preston, T; McMillan, D C

    2007-01-01

    Background The Glasgow Prognostic Score (GPS), an inflammation‐based prognostic score formed from standard thresholds of C reactive protein (CRP) and albumin, has prognostic value in patients with advanced cancer. Little is known about the general biochemical disturbance associated with the systemic inflammatory response in cancer. Aim To examine the relationship between the GPS and blood biochemistry in patients with advanced lung and gastrointestinal cancer. Methods The GPS (albumin <35 g/l = 1 and CRP >10 mg/l = 1 combined to form a prognostic score of 0 (normal) and 1 or 2 (abnormal)) and a variety of biochemical variables were examined in patients (n = 50) with advanced lung or gastrointestinal cancer and in a healthy control group (n = 13). Results The GPS was normal in all the controls, but abnormal in 78% of the cancer group. Serum levels of sodium, chloride, creatine kinase, zinc and vitamin D were lower in the cancer group (all p<0.01), whereas levels of calcium, copper (both p<0.05), alkaline phosphatase, γ‐glutamyl transferase (both p<0.001) and lactate dehydrogenase (p<0.10) were raised. In the patient group, with increasing GPS, there was a median reduction in Karnofsky Performance Status (25%), haemoglobin (22%), sodium (3%), zinc (15%) and survival (93%, all p<0.05) and a median increase in white cell count (129%), alkaline phosphatase (217%), γ‐glutamyl transferase (371%) and lactate dehydrogenase (130%, all p<0.05). CRP levels were strongly and similarly correlated with alkaline phosphatase and γ‐glutamyl transferase, accounting for more than 25% of the variation in their activities. Conclusion Several correlations were seen between biochemical variables and increasing GPS. In particular, chronic activation of the systemic inflammatory response in cancer was associated with increase in γ‐glutamyl transferase and alkaline phosphatase activity in patients with advanced lung and gastrointestinal cancer. PMID:16644880

  9. Proportional Reasoning and Control of Variables in Seven Countries. Advancing Education Through Science-Oriented Programs, Report ID-25.

    ERIC Educational Resources Information Center

    Karplus, Robert; And Others

    Reported are the results of a study of the Piagetian formal thought range of 3600 students, 13 to 15 years old, in seven countries: Denmark, Sweden, Italy, United States, Austria, Germany, and Great Britain. Cognitive measurement was obtained by group administration of two tasks to assess proportional reasoning and control of variables. Overall…

  10. Individual Learner Variables and Their Effect on Mathematics Achievement as Students Advance from Fifth to Sixth Grade

    ERIC Educational Resources Information Center

    Shores, Melanie L.; Shannon, David M.; Smith, Tommy G.

    2010-01-01

    A total of 761 students (58.1% female) from selected fifth- and sixth-grade mathematics classrooms in Alabama were examined to investigate the relationships between individual learner variables (gender, ethnicity, socioeconomic status [SES]) and mathematics performance. Specifically, this portion of the study examined individual learner variables…

  11. Advances in life cycle assessment and emergy evaluation with case studies in gold mining and pineapple production

    NASA Astrophysics Data System (ADS)

    Ingwersen, Wesley W.

    Life cycle assessment (LCA) is an internationally standardized framework for assessing the environmental impacts of products that is rapidly evolving to improve understanding and quantification of how complex product systems depend upon and affect the environment. This dissertation contributes to that evolution through the development of new methods for measuring impacts, estimating the uncertainty of impacts, and measuring ranges of environmental performance, with a focus on product systems in non-OECD countries that have not been well characterized. The integration of a measure of total energy use, emergy, is demonstrated in an LCA of gold from the Yanacocha mine in Peru in the second chapter. A model for estimating the accuracy of emergy results is proposed in the following chapter. The fourth chapter presents a template for LCA-based quantification of the range of environmental performance for tropical agricultural products using the example of fresh pineapple production for export in Costa Rica that can be used to create product labels with environmental information. The final chapter synthesizes how each methodological contribution will together improve the science of measuring product environmental performance.

  12. ADVANCED NUCLEAR FUEL CYCLE EFFECTS ON THE TREATMENT OF UNCERTAINTY IN THE LONG-TERM ASSESSMENT OF GEOLOGIC DISPOSAL SYSTEMS - EBS INPUT

    SciTech Connect

    Sutton, M; Blink, J A; Greenberg, H R; Sharma, M

    2012-04-25

    in borosilicate glass. Because the heat load of the glass was much less than the PWR and BWR assemblies, the glass waste form was able to be co-disposed with the open cycle waste, by interspersing glass waste packages among the spent fuel assembly waste packages. In addition, the Yucca Mountain repository was designed to include some research reactor spent fuel and naval reactor spent fuel, within the envelope that was set using the commercial reactor assemblies as the design basis waste form. This milestone report supports Sandia National Laboratory milestone M2FT-12SN0814052, and is intended to be a chapter in that milestone report. The independent technical review of this LLNL milestone was performed at LLNL and is documented in the electronic Information Management (IM) system at LLNL. The objective of this work is to investigate what aspects of quantifying, characterizing, and representing the uncertainty associated with the engineered barrier are affected by implementing different advanced nuclear fuel cycles (e.g., partitioning and transmutation scenarios) together with corresponding designs and thermal constraints.

  13. Feasibility study for an advanced coal fired heat exchanger/gas turbine topping cycle for a high efficiency power plant. Final report

    SciTech Connect

    Solomon, P.R.; Zhao, Y.; Pines, D.; Buggeln, R.C.; Shamroth, S.J.

    1993-11-01

    Significant improvements in efficiency for the conversion of coal into electricity can be achieved by cycles which employ a high temperature gas turbine topping cycle. The objective of this project is the development of an externally fired gas turbine system. The project computationally tested a new concept for a High Temperature Advanced Furnace (HITAF) and high temperature heat exchanger with a proprietary design to reduce the problems associated with the harsh coal environment. The program addressed two key technology issues: (1) the HITAF/heat exchanger heat transfer through a 2-D computer analysis of the HITAF configuration; (2) 3-D Computational Fluid Dynamics (CFD) model application to simulate the exclusion of particles and corrosive gases from the heat exchanger surface. The basic concept of this new combustor design was verified through the 2D and 3D modeling. It demonstrated that the corrosion and erosion of the exchanger material caused by coal and ash particles can be largely reduced by employing a specially designed firing scheme. It also suggested that a proper combustion geometry design is necessary to maximize the cleaning effect.

  14. Targeting human immunodeficiency virus type 1 reverse transcriptase by intracellular expression of single-chain variable fragments to inhibit early stages of the viral life cycle.

    PubMed Central

    Shaheen, F; Duan, L; Zhu, M; Bagasra, O; Pomerantz, R J

    1996-01-01

    Novel molecular approaches to inhibit human immunodeficiency virus type 1 (HIV-1) infection have received increasing attention because of the lack of effective antiviral drug therapies in vivo. We now demonstrate that cells can be intracellularly immunized by cytoplasmic expression of single-chain variable antibody fragments (SFv) which bind to the HIV-1 reverse transcriptase (RT) enzyme. The expression of anti-RT SFv in T-lymphocytic cells specifically neutralizes the RT activity in the preintegration stage and affects the reverse transcription process, an early event of the HIV-1 life cycle. Blocking the virus at these early stages dramatically decreased HIV-1 propagation, as well as the HIV-1-induced cytopathic effects in susceptible human T lymphocytes, by impeding the formation of the proviral DNA. These data also demonstrate that intracellular, complete SFvs may gain access to viral proteins of the HIV-1 preintegration complex. These SFvs will provide a tool with which to better understand the molecular mechanisms involved in restricting viral replication in HIV-1-infected cells. PMID:8648670

  15. Test Requirements and Conceptual Design for a Potassium Test Loop to Support an Advanced Potassium Rankine Cycle Power Conversion Systems

    SciTech Connect

    Yoder, JR.G.L.

    2006-03-08

    Parameters for continuing the design and specification of an experimental potassium test loop are identified in this report. Design and construction of a potassium test loop is part of the Phase II effort of the project ''Technology Development Program for an Advanced Potassium Rankine Power Conversion System''. This program is supported by the National Aeronautics and Space Administration. Design features for the potassium test loop and its instrumentation system, specific test articles, and engineered barriers for ensuring worker safety and protection of the environment are described along with safety and environmental protection requirements to be used during the design process. Information presented in the first portion of this report formed the basis to initiate the design phase of the program; however, the report is a living document that can be changed as necessary during the design process, reflecting modifications as additional design details are developed. Some portions of the report have parameters identified as ''to be determined'' (TBD), reflecting the early stage of the overall process. In cases where specific design values are presently unknown, the report attempts to document the quantities that remain to be defined in order to complete the design of the potassium test loop and supporting equipment.

  16. ADVANCED MONITORING TO IMPROVE COMBUSTION TURBINE/COMBINED CYCLE CT/(CC) RELIABILITY, AVAILABILITY AND MAINTAINABILITY (RAM)

    SciTech Connect

    Leonard Angello

    2004-09-30

    Power generators are concerned with the maintenance costs associated with the advanced turbines that they are purchasing. Since these machines do not have fully established operation and maintenance (O&M) track records, power generators face financial risk due to uncertain future maintenance costs. This risk is of particular concern, as the electricity industry transitions to a competitive business environment in which unexpected O&M costs cannot be passed through to consumers. These concerns have accelerated the need for intelligent software-based diagnostic systems that can monitor the health of a combustion turbine in real time and provide valuable information on the machine's performance to its owner/operators. EPRI, Impact Technologies, Boyce Engineering, and Progress Energy have teamed to develop a suite of intelligent software tools integrated with a diagnostic monitoring platform that will, in real time, interpret data to assess the ''total health'' of combustion turbines. The Combustion Turbine Health Management System (CTHM) will consist of a series of dynamic link library (DLL) programs residing on a diagnostic monitoring platform that accepts turbine health data from existing monitoring instrumentation. The CTHM system will be a significant improvement over currently available techniques for turbine monitoring and diagnostics. CTHM will interpret sensor and instrument outputs, correlate them to a machine's condition, provide interpretative analyses, project servicing intervals, and estimate remaining component life. In addition, it will enable real-time anomaly detection and diagnostics of performance and mechanical faults, enabling power producers to more accurately predict critical component remaining useful life and turbine degradation.

  17. Hydrological partitioning in the critical zone: Recent advances and opportunities for developing transferable understanding of water cycle dynamics

    NASA Astrophysics Data System (ADS)

    Brooks, Paul D.; Chorover, Jon; Fan, Ying; Godsey, Sarah E.; Maxwell, Reed M.; McNamara, James P.; Tague, Christina

    2015-09-01

    Hydrology is an integrative discipline linking the broad array of water-related research with physical, ecological, and social sciences. The increasing breadth of hydrological research, often where subdisciplines of hydrology partner with related sciences, reflects the central importance of water to environmental science, while highlighting the fractured nature of the discipline itself. This lack of coordination among hydrologic subdisciplines has hindered the development of hydrologic theory and integrated models capable of predicting hydrologic partitioning across time and space. The recent development of the concept of the critical zone (CZ), an open system extending from the top of the canopy to the base of groundwater, brings together multiple hydrological subdisciplines with related physical and ecological sciences. Observations obtained by CZ researchers provide a diverse range of complementary process and structural data to evaluate both conceptual and numerical models. Consequently, a cross-site focus on "critical zone hydrology" has potential to advance the discipline of hydrology and to facilitate the transition of CZ observatories into a research network with immediate societal relevance. Here we review recent work in catchment hydrology and hydrochemistry, hydrogeology, and ecohydrology that highlights a common knowledge gap in how precipitation is partitioned in the critical zone: "how is the amount, routing, and residence time of water in the subsurface related to the biogeophysical structure of the CZ?" Addressing this question will require coordination among hydrologic subdisciplines and interfacing sciences, and catalyze rapid progress in understanding current CZ structure and predicting how climate and land cover changes will affect hydrologic partitioning.

  18. ADVANCED MONITORING TO IMPROVE COMBUSTION TURBINE/COMBINED CYCLE CT/(CC) RELIABILITY, AVAILABILITY AND MAINTAINABILITY (RAM)

    SciTech Connect

    Leonard Angello

    2004-03-31

    Power generators are concerned with the maintenance costs associated with the advanced turbines that they are purchasing. Since these machines do not have fully established operation and maintenance (O&M) track records, power generators face financial risk due to uncertain future maintenance costs. This risk is of particular concern, as the electricity industry transitions to a competitive business environment in which unexpected O&M costs cannot be passed through to consumers. These concerns have accelerated the need for intelligent software-based diagnostic systems that can monitor the health of a combustion turbine in real time and provide valuable information on the machine's performance to its owner/operators. EPRI, Impact Technologies, Boyce Engineering, and Progress Energy have teamed to develop a suite of intelligent software tools integrated with a diagnostic monitoring platform that will, in real time, interpret data to assess the ''total health'' of combustion turbines. The Combustion Turbine Health Management System (CTHM) will consist of a series of dynamic link library (DLL) programs residing on a diagnostic monitoring platform that accepts turbine health data from existing monitoring instrumentation. The CTHM system will be a significant improvement over currently available techniques for turbine monitoring and diagnostics. CTHM will interpret sensor and instrument outputs, correlate them to a machine's condition, provide interpretative analyses, project servicing intervals, and estimate remaining component life. In addition, it will enable real-time anomaly detection and diagnostics of performance and mechanical faults, enabling power producers to more accurately predict critical component remaining useful life and turbine degradation.

  19. Sustainability Efficiency Factor: Measuring Sustainability in Advanced Energy Systems through Exergy, Exergoeconomic, Life Cycle, and Economic Analyses

    NASA Astrophysics Data System (ADS)

    Boldon, Lauren

    The Encyclopedia of Life Support Systems defines sustainability or industrial ecology as "the wise use of resources through critical attention to policy, social, economic, technological, and ecological management of natural and human engineered capital so as to promote innovations that assure a higher degree of human needs fulfilment, or life support, across all regions of the world, while at the same time ensuring intergenerational equity" (Encyclopedia of Life Support Systems 1998). Developing and integrating sustainable energy systems to meet growing energy demands is a daunting task. Although the technology to utilize renewable energies is well understood, there are limited locations which are ideally suited for renewable energy development. Even in areas with significant wind or solar availability, backup or redundant energy supplies are still required during periods of low renewable generation. This is precisely why it would be difficult to make the switch directly from fossil fuel to renewable energy generation. A transition period in which a base-load generation supports renewables is required, and nuclear energy suits this need well with its limited life cycle emissions and fuel price stability. Sustainability is achieved by balancing environmental, economic, and social considerations, such that energy is produced without detriment to future generations through loss of resources, harm to the environment, etcetera. In essence, the goal is to provide future generations with the same opportunities to produce energy that the current generation has. This research explores sustainability metrics as they apply to a small modular reactor (SMR)-hydrogen production plant coupled with wind energy and storage technologies to develop a new quantitative sustainability metric, the Sustainability Efficiency Factor (SEF), for comparison of energy systems. The SEF incorporates the three fundamental aspects of sustainability and provides SMR or nuclear hybrid energy system

  20. Dissolved Silver in Marine Waters: Reviewing Three Decades of Advances in Analytical Techniques and Understanding its Biogeochemical Cycling

    NASA Astrophysics Data System (ADS)

    Ndungu, K.; Flegal, A. R., Jr.

    2015-12-01

    Although billions of dollars have been spent over the past half-century to reduce contamination of U.S. waters, quantifying parts-per-billion reductions in surface water concentration since has been relatively unsuccessful. The reasons for the failure in identifying the benefits of these remediative efforts include: (i) historic (pre-1980) problems in accurately sampling and analyzing trace element concentrations at parts-per-billion level, so that temporal reductions in trace metal contamination reflected improved sampling and analytical accuracy rather than real decreases in those concentrations; (ii) limited seasonal and long term research. Silver in its ionic form is more toxic to aquatic organisms than any other metal except Hg. Because Ag is not common naturally in the environment, its elevated presence in water, sediment or biological tissues is usually indicative of anthropogenic influences. However, there is very little published data on Ag levels in both water and sediment. The published studies include Ag levels in a few U.S. estuarine waters, including detailed and time series studies for the San Francisco Estuary system by the WIGS lab at UC Santa Cruz. In the open Ocean, Ag measurements are limited to a few studies in the North and South Pacific, The North and South Atlantic. However, as Gallon and Flegal recently noted, there is no available data on Ag concentrations from the Indian Ocean! Most of the dissolved Ag data from the Atlantic was made in WIGS lab at UC Santa Cruz Analytical determination of Ag in seawater has come a long way since Murozumi reported the first dissolved Ag measurements from the N. Pacific in 1981 using isotope dilution MS after solvent extraction. In this presentation I will review analytical developments for Ag determination in the last three decades. I will also highlight the missing data gaps and present new tentative data on dissolved Ag concentration and cycling in polar regions including the Antarctic (Amundsen Sea

  1. The sea surface temperature field in the Eastern Mediterranean from advanced very high resolution radiometer (AVHRR) data. Part II. Interannual variability

    NASA Astrophysics Data System (ADS)

    Marullo, S.; Santoleri, R.; Malanotte-Rizzoli, P.; Bergamasco, A.

    1999-04-01

    A ten-year dataset of AVHRR-SST (Sea Surface Temperature) with 18 km space resolution and weekly frequency has been analyzed in the Eastern Mediterranean. In Part I of the present study, we examined the seasonal variability of the basin and we defined the time and space scales of the monthly climatologies of the sea surface temperature distributions. A detailed and quantitative comparison was also carried out between the SST distribution of September 1987 and the surface temperature map of the corresponding hydrological survey of the POEM (Physical Oceanography of the Eastern Mediterranean) Programme. In this second part, we extend the analysis to examine and quantify the interannual variabilities. We summarize our results as follows. The analysis reveals the presence of an interannual cycle in the Ionian basin in the decade 1983-1992. The climatological pattern of the isotherms oscillates between two main states corresponding to the winter (zonal) and the summer (meridional) distributions. The apparent interannual cycle appears in the SST distribution only in winter and only in the Ionian basin, while the Levantine basin shows only fluctuations around the climatology. Thus, the interannual signal in our dataset is present but is much less important than the seasonal one. To confirm and quantify the above conclusions, we evaluate the Empirical Orthogonal Function of the SST time series. Gradient EOF's modes show the presence of a very strong yearly signal explaining 60% of the variance and a less intense seasonal signal that account for 16% of the variance. No interannual variability is represented by EOF gradient modes even though it can be observed in the increasing trend of the time varying amplitude of the first EOF mode. To observe the interannual variability signal, a seasonal temperature cycle was subtracted from each image instead of the ensemble (spatial) mean. A new EOF mode that accounts for 20% of the variance emerges between the first and second

  2. ADVANCED MONITORING TO IMPROVE COMBUSTION TURBINE/COMBINED CYCLE CT/(CC) RELIABILITY, AVAILABILITY AND MAINTAINABILITY (RAM)

    SciTech Connect

    Leonard Angello

    2003-09-30

    Power generators are concerned with the maintenance costs associated with the advanced turbines that they are purchasing. Since these machines do not have fully established operation and maintenance (O&M) track records, power generators face financial risk due to uncertain future maintenance costs. This risk is of particular concern, as the electricity industry transitions to a competitive business environment in which unexpected O&M costs cannot be passed through to consumers. These concerns have accelerated the need for intelligent software-based diagnostic systems that can monitor the health of a combustion turbine in real time and provide valuable information on the machine's performance to its owner/operators. Such systems would interpret sensor and instrument outputs, correlate them to the machine's condition, provide interpretative analyses, forward projections of servicing intervals, estimate remaining component life, and identify faults. EPRI, Impact Technologies, Boyce Engineering, and Progress Energy have teamed to develop a suite of intelligent software tools integrated with a diagnostic monitoring platform that will, in real time, interpret data to assess the ''total health'' of combustion turbines. The Combustion Turbine Health Management System (CTHM) will consist of a series of dynamic link library (DLL) programs residing on a diagnostic monitoring platform that accepts turbine health data from existing monitoring instrumentation. The CTHM system will be a significant improvement over currently available techniques for turbine monitoring and diagnostics. CTHM will interpret sensor and instrument outputs, correlate them to a machine's condition, provide interpretative analyses, project servicing intervals, and estimate remaining component life. In addition, it will enable real-time anomaly detection and diagnostics of performance and mechanical faults, enabling power producers to more accurately predict critical component remaining useful life and

  3. Model aerodynamic test results for two variable cycle engine coannular exhaust systems at simulated takeoff and cruise conditions. [Lewis 8 by 6-foot supersonic wind tunnel tests

    NASA Technical Reports Server (NTRS)

    Nelson, D. P.

    1980-01-01

    Wind tunnel tests were conducted to evaluate the aerodynamic performance of a coannular exhaust nozzle for a proposed variable stream control supersonic propulsion system. Tests were conducted with two simulated configurations differing primarily in the fan duct flowpaths: a short flap mechanism for fan stream control with an isentropic contoured flow splitter, and an iris fan nozzle with a conical flow splitter. Both designs feature a translating primary plug and an auxiliary inlet ejector. Tests were conducted at takeoff and simulated cruise conditions. Data were acquired at Mach numbers of 0, 0.36, 0.9, and 2.0 for a wide range of nozzle operating conditions. At simulated supersonic cruise, both configurations demonstrated good performance, comparable to levels assumed in earlier advanced supersonic propulsion studies. However, at subsonic cruise, both configurations exhibited performance that was 6 to 7.5 percent less than the study assumptions. At take off conditions, the iris configuration performance approached the assumed levels, while the short flap design was 4 to 6 percent less.

  4. Reactor physics studies for the Advanced Fuel Cycle Initiative (AFCI) Reactor-Accelerator Coupling Experiments (RACE) Project

    NASA Astrophysics Data System (ADS)

    Stankovskiy, Evgeny Yuryevich

    In the recently completed RACE Project of the AFCI, accelerator-driven subcritical systems (ADS) experiments were conducted to develop technology of coupling accelerators to nuclear reactors. In these experiments electron accelerators induced photon-neutron reactions in heavy-metal targets to initiate fission reactions in ADS. Although the Idaho State University (ISU) RACE ADS was constructed only to develop measurement techniques for advanced experiments, many reactor kinetics experiments were conducted there. In the research reported in this dissertation, a method was developed to calculate kinetics parameters for measurement and calculation of the reactivity of ADS, a safety parameter that is necessary for control and monitoring of power production. Reactivity is measured in units of fraction of delayed versus prompt neutron from fission, a quantity that cannot be directly measured in far-subcritical reactors such as the ISU RACE configuration. A new technique is reported herein to calculate it accurately and to predict kinetic behavior of a far-subcritical ADS. Experiments conducted at ISU are first described and experimental data are presented before development of the kinetic theory used in the new computational method. Because of the complexity of the ISU ADS, the Monte-Carlo method as applied in the MCNP code is most suitable for modeling reactor kinetics. However, the standard method of calculating the delayed neutron fraction produces inaccurate values. A new method was developed and used herein to evaluate actual experiments. An advantage of this method is that its efficiency is independent of the fission yield of delayed neutrons, which makes it suitable for fuel with a minor actinide component (e.g. transmutation fuels). The implementation of this method is based on a correlated sampling technique which allows the accurate evaluation of delayed and prompt neutrons. The validity of the obtained results is indicated by good agreement between experimental

  5. Solar Cycle 23: An Anomalous Cycle?

    NASA Astrophysics Data System (ADS)

    de Toma, Giuliana; White, Oran R.; Chapman, Gary A.; Walton, Stephen R.; Preminger, Dora G.; Cookson, Angela M.

    2004-07-01

    The latest SOHO VIRGO total solar irradiance (TSI) time series is analyzed using new solar variability measures obtained from full-disk solar images made at the San Fernando Observatory and the Mg II 280 nm index. We discuss the importance of solar cycle 23 as a magnetically simpler cycle and a variant from recent cycles. Our results show the continuing improvement in TSI measurements and surrogates containing information necessary to account for irradiance variability. Use of the best surrogate for irradiance variability due to photospheric features (sunspots and faculae) and chromospheric features (plages and bright network) allows fitting the TSI record to within an rms difference of 130 ppm for the period 1986 to the present. Observations show that the strength of the TSI cycle did not change significantly despite the decrease in sunspot activity in cycle 23 relative to cycle 22. This points to the difficulty of modeling TSI back to times when only sunspot observations were available.

  6. Variable neutron star free precession in Hercules X-1 from evolution of RXTE X-ray pulse profiles with phase of the 35-d cycle

    NASA Astrophysics Data System (ADS)

    Postnov, K.; Shakura, N.; Staubert, R.; Kochetkova, A.; Klochkov, D.; Wilms, J.

    2013-10-01

    Accretion of matter on to the surface of a freely precessing neutron star (NS) with a complex non-dipole magnetic field can explain the change of X-ray pulse profiles of Her X-1 observed by RXTE with the phase of the 35-d cycle. We demonstrate this using all available measurements of X-ray pulse profiles in the 9-13 keV energy range obtained with the RXTE/Proportional Counter Array (PCA). The measured profiles guided the elaboration of a geometrical model and the definition of locations of emitting poles, arcs and spots on the NS surface which satisfactorily reproduce the observed pulse profiles and their dependence on free precession phase. We have found that the observed trend of the times of the 35-d turn-ons on the O-C diagram, which can be approximated by a collection of consecutive linear segments around the mean value, can be described by our model by assuming a variable free precession period, with a fractional period change of about a few per cent. Under this assumption and using our model, we have found that the times of phase zero of the NS free precession (which we identify with the maximum separation of the brightest spot on the NS surface with the NS spin axis) occur about 1.6 d after the mean turn-on times inside each `stable' epoch, producing a linear trend on the O-C diagram with the same slope as the observed times of turn-ons. We propose that the 2.5 per cent changes in the free precession period that occur on time scales of several to tens of 35-d cycles can be related to wandering of the principal inertia axis of the NS body due to variations in the patterns of accretion on to the NS surface. The closeness of periods of the disc precession and the NS free precession can be explained by the presence of a synchronization mechanism in the system, which modulates the dynamical interaction of the gas streams and the accretion disc with the NS free precession period.

  7. Simulation and experimental design of a new advanced variable step size Incremental Conductance MPPT algorithm for PV systems.

    PubMed

    Loukriz, Abdelhamid; Haddadi, Mourad; Messalti, Sabir

    2016-05-01

    Improvement of the efficiency of photovoltaic system based on new maximum power point tracking (MPPT) algorithms is the most promising solution due to its low cost and its easy implementation without equipment updating. Many MPPT methods with fixed step size have been developed. However, when atmospheric conditions change rapidly , the performance of conventional algorithms is reduced. In this paper, a new variable step size Incremental Conductance IC MPPT algorithm has been proposed. Modeling and simulation of different operational conditions of conventional Incremental Conductance IC and proposed methods are presented. The proposed method was developed and tested successfully on a photovoltaic system based on Flyback converter and control circuit using dsPIC30F4011. Both, simulation and experimental design are provided in several aspects. A comparative study between the proposed variable step size and fixed step size IC MPPT method under similar operating conditions is presented. The obtained results demonstrate the efficiency of the proposed MPPT algorithm in terms of speed in MPP tracking and accuracy. PMID:26337741

  8. The impact of surface dust source exhaustion on the martian dust cycle, dust storms and interannual variability, as simulated by the MarsWRF General Circulation Model

    NASA Astrophysics Data System (ADS)

    Newman, Claire E.; Richardson, Mark I.

    2015-09-01

    Observations of albedo on Mars suggest a largely invariant long-term mean surface dust distribution, but also reveal variations on shorter (seasonal to annual) timescales, particularly associated with major dust storms. We study the impact of finite surface dust availability on the dust cycle in the MarsWRF General Circulation Model (GCM), which uses radiatively active dust with parameterized 'dust devil' and wind stress dust lifting to enable the spontaneous production of dust storms, and tracks budgets of dust lifting, deposition, and total surface dust inventory. We seek a self-consistent, long-term 'steady state' dust cycle for present day Mars, consisting of (a) a surface dust distribution that varies from year to year but is constant longer-term and in balance with current dust redistribution processes, and (b) a fixed set of dust lifting parameters that continue to produce major storms for this distribution of surface dust. We relax the GCM's surface dust inventory toward this steady state using an iterative process, in which dust lifting rate parameters are increased as progressively more surface sites are exhausted of dust. Late in the equilibration process, the GCM exhibits quasi-steady state behavior in which few new surface grid points are exhausted during a 60 year period with constant dust lifting parameters. Complex regional-scale dust redistribution occurs on time-scales from less than seasonal to decadal, and the GCM generates regional to global dust storms with many realistic features. These include merging regional storms, cross-equatorial storms, and the timing and location of several storm types, though very early major storms and large amounts of late storm activity are not reproduced. Surface dust availability in key onset and growth source regions appears vital for 'early' major storms, with replenishment of these regions required before another large storm can occur, whereas 'late' major storms appear primarily dependent on atmospheric

  9. The study of variability of TEC over mid-latitude American regions during the ascending phase of solar cycle 24 (2009-2011)

    NASA Astrophysics Data System (ADS)

    Asmare Tariku, Yekoye

    2016-08-01

    This paper deals with the pattern of the variability of the Global Positioning System vertical total electron content (GPS VTEC) and the modeled vertical total electron content (IRI 2012 TEC) over American mid-latitude regions during the rising phase of solar cycle 24 (2009-2011). This has been conducted employing ground-based dual frequency GPS receiver installed at Mississippi County Airport (geographic lat. 36.85°N and long. 270.64°E). In this work, the monthly and seasonal variations in the measured VTEC have been analyzed and compared with the VTEC inferred from IRI-2012 model. It has been shown that the monthly and seasonal mean VTEC values get decreased mostly between 05:00 and 10:00 UT and reach their minimal nearly at around 10:00 UT for both the experimental and the model. The VTEC values then get increased and reach the peak values at around 20:00 UT and decrease again. Moreover, it is depicted that the model better estimates both the monthly and seasonal mean hourly VTEC values mostly between 15:00 and 20:00 UT. The modeled monthly and seasonal VTEC values are smaller than the corresponding measured values as the solar activity decreases when all options for the topside electron density are used. However, as the Sun goes from a very low to a high solar activity, the overestimation performance of the VTEC values derived from the model increases. The overall results show that it is generally better to use the model with IRI-2000 option for the topside electron density in estimating the monthly and seasonal VTEC variations, especially when the activity of the Sun decreases.

  10. Production dynamics and life cycle of dominant chironomids (diptera, chironomidae) in a subtropical stream in China: adaptation to variable flow conditions in summer and autumn

    NASA Astrophysics Data System (ADS)

    Yan, Yunjun; Li, Xiaoyu

    2007-07-01

    The production dynamics and trophic basis of 7 dominant species of chironomids were investigated in the area of a second-order river of the Hanjiang River basin, in central China from June 2003 to June 2004. The results showed that Tvetenia discoloripes was by far the most abundant chironomid, dominating the overall standing stock of the taxa. In terms of lif ecycle, Chaetocladius sp., Eukiefferiella potthasti and T. discoloripes developed 1 generation a year, whereas Microtendipes sp. and Pagastia sp. developed two, while Pentaneura sp. and Polypedilum sp. developed three. T. discoloripes was the most productive chironomid with 120.305 8 g/m2. a, Pentaneura sp. and E. potthasti had relatively high production values of >17 g/m2.a, and the rest were <10 g/m2.a. All the production temporal variation tended to follow biomass patterns. T. discoloripes, Chaetocladius sp. and Pagastia sp. concentrated most of their production in winter, whereas E. potthasti, Pentaneura sp. and Polypedilum sp. had relatively higher production throughout the year. Only Microtendipes sp. had a production that peaked in summer. The overlap in temporal distribution of production among the chironomid species was generally high (>0.5), especially for filter-collectors Microtendipes sp., Chaetocladius sp., Chaetocladius sp., T. discoloripes and Pagastia sp. All species except Pentaneura sp. consumed a large portion of amorphous detritus, constituting more than 90% of their diets, and contributing nearly 90% to their secondary production. All the 7 chironomids represent obvious adaptation to local highly variable climate in summer and autumn in life cycle pattern, production dynamics, and food type.

  11. Advanced embedded nonlinear observer design and HIL validation using a Takagi-Sugeno approach with unmeasurable premise variables

    NASA Astrophysics Data System (ADS)

    Olteanu, S. C.; Aitouche, A.; Belkoura, L.

    2014-12-01

    The article's goals are to illustrate the feasibility of implementing a Takagi Sugeno state observer on an embedded microcontroller based platform and secondly to present a methodology for validating a physical embedded system using a Hardware In The Loop architecture, where a simulation software replaces the process. As an application, a three water tank system was chosen. For the validation part, LMS AMESim software is employed to reproduce the process behaviour. The interface to the embedded platform is assured by Simulink on a Windows operating system, chosen as it is the most commonly used operating system. The lack of real time behaviour of the operating system is compensated by a real time kernel that manages to offer deterministic response times. The Takagi-Sugeno observer in the case of this process has the complex form that considers the premise variables to be unmeasurable. The embedded system consists of two Arduino boards connected in parallel, thus offering distributed resources.

  12. Using System Mass (SM), Equivalent Mass (EM), Equivalent System Mass (ESM) or Life Cycle Mass (LCM) in Advanced Life Support (ALS) Reporting

    NASA Technical Reports Server (NTRS)

    Jones, Harry

    2003-01-01

    The Advanced Life Support (ALS) has used a single number, Equivalent System Mass (ESM), for both reporting progress and technology selection. ESM is the launch mass required to provide a space system. ESM indicates launch cost. ESM alone is inadequate for technology selection, which should include other metrics such as Technology Readiness Level (TRL) and Life Cycle Cost (LCC) and also consider perfom.arxe 2nd risk. ESM has proven difficult to implement as a reporting metric, partly because it includes non-mass technology selection factors. Since it will not be used exclusively for technology selection, a new reporting metric can be made easier to compute and explain. Systems design trades-off performance, cost, and risk, but a risk weighted cost/benefit metric would be too complex to report. Since life support has fixed requirements, different systems usually have roughly equal performance. Risk is important since failure can harm the crew, but it is difficult to treat simply. Cost is not easy to estimate, but preliminary space system cost estimates are usually based on mass, which is better estimated than cost. Amass-based cost estimate, similar to ESM, would be a good single reporting metric. The paper defines and compares four mass-based cost estimates, Equivalent Mass (EM), Equivalent System Mass (ESM), Life Cycle Mass (LCM), and System Mass (SM). EM is traditional in life support and includes mass, volume, power, cooling and logistics. ESM is the specifically defined ALS metric, which adds crew time and possibly other cost factors to EM. LCM is a new metric, a mass-based estimate of LCC measured in mass units. SM includes only the factors of EM that are originally measured in mass, the hardware and logistics mass. All four mass-based metrics usually give similar comparisons. SM is by far the simplest to compute and easiest to explain.

  13. Linear variable differential transformer (LVDT)-based elongation measurements in Advanced Test Reactor high temperature irradiation testing

    SciTech Connect

    D. L. Knudson; J. L. Rempe

    2012-02-01

    New materials are being considered for fuel, cladding, and structures in next generation and existing nuclear reactors. These materials can undergo significant dimensional and physical changes during high temperature irradiations. Currently, such changes are determined by repeatedly irradiating a specimen for a specified period of time in the Advanced Test Reactor (ATR) and then removing it from the reactor for evaluation. The labor and time to remove, examine, and return irradiated samples for each measurement makes this approach very expensive. In addition, such techniques provide limited data and may disturb the phenomena of interest. To resolve these issues, an instrumented creep testing capability is being developed for specimens irradiated in pressurized water reactor (PWR) coolant conditions in the ATR at the Idaho National Laboratory (INL). This paper reports the status of INL efforts to develop this testing capability. In addition to providing an overview of in-pile creep test capabilities available at other test reactors, this paper focuses on efforts to design and evaluate a prototype test rig in an autoclave at INL's High Temperature Test Laboratory (HTTL).

  14. Linear variable differential transformer (LVDT)-based elongation measurements in Advanced Test Reactor high temperature irradiation testing

    SciTech Connect

    D. L. Knudson; J. L. Rempe

    2012-02-01

    New materials are being considered for fuel, cladding and structures in next generation and existing nuclear reactors. These materials can undergo significant dimensional and physical changes during high temperature irradiations. Currently, such changes are determined by repeatedly irradiating a specimen for a specified period of time in the Advanced Test Reactor (ATR) and then removing it from the reactor for evaluation. The labor and time to remove, examine and return irradiated samples for each measurement make this approach very expensive. In addition, such techniques provide limited data and may disturb the phenomena of interest. To resolve these issues, an instrumented creep testing capability is being developed for specimens irradiated under pressurized water reactor coolant conditions in the ATR at the Idaho National Laboratory (INL). This paper reports the status of INL efforts to develop this testing capability. In addition to providing an overview of in-pile creep test capabilities available at other test reactors, this paper focuses on efforts to design and evaluate a prototype test rig in an autoclave at INL’s High Temperature Test Laboratory.

  15. Outdoor test stand performance of a convertible engine with variable inlet guide vanes for advanced rotorcraft propulsion

    NASA Technical Reports Server (NTRS)

    Mcardle, Jack G.

    1986-01-01

    A variable inlet guide van (VIGV) type convertible engine that could be used to power future high-speed rotorcraft was tested on an outdoor stand. The engine ran stably and smoothly in the turbofan, turboshaft, and dual (combined fan and shaft) power modes. In the turbofan mode with the VIGV open fuel consumption was comparable to that of a conventional turbofan engine. In the turboshaft mode with the VIGV closed fuel consumption was higher than that of present turboshaft engines because power was wasted in churning fan-tip airflow. In dynamic performance tests with a specially built digital engine control and using a waterbrake dynamometer for shaft load, the engine responded effectively to large steps in thrust command and shaft torque. Previous mission analyses of a conceptual X-wing rotorcraft capable of 400-knot cruise speed were revised to account for more fan-tip churning power loss than was originally estimated. The new calculations confirm that using convertible engines rather than separate lift and cruise engines would result in a smaller, lighter craft with lower fuel use and direct operating cost.

  16. Recent advances in microprocessor control and variable speed drive strategies for small wood-fired boilers: A case study

    SciTech Connect

    Clunie, R.; Guibord, R.; Gregoire, R.

    1994-01-01

    Saunders Brothers' wood products company has watched the steady growth of its neighboring community in Westbrook to the point where neighborhood housing is now within a few feet of the plant property. The Saunders Brothers' boiler plant consists of two HRT boilers which burn only bark and wood sawmill wastes and shavings generated by the manufacturing plant. Although technically in compliance with State of Maine environmental laws, Saunders Brothers was concerned with the visible emissions and fly ash emanating from the plant site. Wishing to maintain its status as a good neighbor, in 1989 Saunders Brothers' boiler plant was extensively renovated. Part of these modifications consisted of changing over to automatic microprocessor combustion controls and installing AC variable frequency drives on the combustion air fans and fuel feed screws. The purpose of adopting the microprocessor-based combustion control approach to solve the air pollution problem at Saunders Brothers was two-fold. The control package takes complete control of the fuel feed and combustion processes. By accurately metering the fuel supply and the air supply to the firebox, usual large air volumes and resultant velocities are reduced and controlled. At the same time all particulate emissions are greatly reduced, and all visible emissions are eliminated. A side benefit of installing the new combustion control system was an expected fuel savings of approximately 20% to 25%.

  17. Development of Technologies for the Simultaneous Separation of Cesium and Strontium from Spent Nuclear Fuel as Part of an Advanced Fuel Cycle

    SciTech Connect

    Jack D. Law; R. Scott HErbst; David H. Meikrantz; Dean R. Peterman; Catherine L. Riddle; Richard D. Tillotson; Terry A. Todd

    2005-04-01

    As part of the Advanced Fuel Cycle Initiative, two solvent extraction technologies are being developed to simultaneously separate cesium and strontium from dissolved spent nuclear fuel. The first process utilizes a solvent consisting of chlorinated cobalt dicarbollide and polyethylene glycol extractants in a phenyltrifluoromethyl sulfone diluent. Recent improvements to the process include development of a new, non-nitroaromatic diluent and development of new stripping reagents, including a regenerable strip reagent that can be recovered and recycled. Countercurrent flowsheets have been designed and tested on simulated and actual spent nuclear fuel feed streams with both cesium and strontium removal efficiencies of greater than 99 %. The second process developed to simultaneously separate cesium and strontium from spent nuclear fuel is based on two highly-specific extractants: 4,4',(5')-Di-(t-butyldicyclo-hexano)-18-crown-6 (DtBuCH18C6) and Calix[4]arene-bis-(tert-octylbenzo-crown-6) (BOBCalixC6). The DtBuCH18C6 extractant is selective for strontium and the BOBCalixC6 extractant is selective for cesium. A solvent composition has been developed that enables both elements to be removed together and, in fact, a synergistic effect was observed with strontium distributions in the combined solvent that are much higher that in the strontium extraction (SREX) process. Initial laboratory test results of the new combined cesium and strontium extraction process indicate good extraction and stripping performance. A flowsheet for treatment of spent nuclear fuel is currently being developed.

  18. A variable geometry combustor for broadened properties fuels

    NASA Technical Reports Server (NTRS)

    Dodds, W. J.; Fear, J. S.

    1987-01-01

    A program was conducted to design and develop a variable geometry combustor, sized for the cycle and envelope of a large commercial turbofan engine. The combustor uses a variable area swirl cup to control stoichiometry in the primary combustion zone. Potential advantages of this design include improved capability to burn non-standard fuels, short system length, and increased operating temperature range for advanced high performance engine cycles. After considerable development, key program emissons and performance goals were met with the variable geometry combustor. Primary development efforts were to evolve improved variable swirl cup configurations. In particular, air leakage through the variable<