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Sample records for power ascension strategy

  1. Power ascension strategy following a reactor trip during EOC coastdown

    SciTech Connect

    Beard, C.L.; Heibel, M.D. ); Lesnick, D.C. )

    1992-01-01

    The difficulties associated with returning a reactor to the pretrip power level following a reactor trip during an end-of-cycle (EOC) power coastdown maneuver, and maintaining it once achieved, have caused utilities to abandon the restart and enter their refueling outages ahead of schedule. The Commonwealth Edison Company (CECo) Braidwood and Byron units have experienced reactor trips during EOC power coastdown maneuvers and have successfully performed restarts. The installation of the BEACON core monitoring system, which provides core monitoring, measurement reduction, core analysis and follow, and core prediction capability utilizing a very fast and accurate three-dimensional nodal code, at the CECo Byron, Braidwood, and Zion stations allows the reactor engineers at these units to accurately determine reactor response. The capabilities of the BEACON system allow an optimal return to power strategy to be developed and continuously updated. This paper presents a method for establishing the optimal return to power strategy utilizing the BEACON system.

  2. Final Report: Phase II Geothermal Exploration and Geothermal Power Plant Update for Ascension Island, South Atlantic Ocean

    SciTech Connect

    Nielson, D.L.; Sibbett, B.S.; Shane, M.K.; Whitbeck, J.F.

    1984-07-01

    The Phase I study of the geothermal potential of Ascension Island concluded that the possibility of a geothermal resource existing under the island was excellent. This conclusion was based on the presence of young volcanic rocks (a heat source close to the surface), an ample supply of water from the sea, and high permeability of many of the rocks which make up the island. The assumption was made that the resource would be similar to geothermal systems in the Azores or Japan, and a conceptual design of a power plant to utilize the resource was prepared upon which cost estimates and an economic analysis were subsequently performed. The results of the economic analysis were very favorable, and the Air Force decided to proceed into Phase II of the project. Under Phase II, an exploration program was designed and carried out. The purpose of the program was to ascertain whether or not a geothermal resource existed beneath Ascension island and, to the extent possible, to evaluate the quality of that resource. The exploration involved a detailed aeromagnetic survey of the island, reconnaissance and detailed electrical resistivity surveys, and drilling of holes for the measurement of temperatures. These methods have confirmed the existence of geothermal activity beneath Ascension. Measured temperature gradients and bottom hole temperatures as well as chemical geothermometers indicate temperatures sufficient for the generation of electricity within reasonable drilling depths. This report documents those conclusions and the supporting data. This report also documents the results of the power plant update with new data supplied from the Phase II exploration activities on the island. The power plant scenario has been changed to reflect the fact that the resource temperature may not be as high as that originally assumed in the Phase I study, the location of the production wells will in all likelihood be farther from the existing Air Force facilities--either north of Grazing

  3. Six Months in Ascension

    NASA Astrophysics Data System (ADS)

    Black Gill, Isobel Sarah; Gill, David

    2010-06-01

    Introduction David Gill; 1. Why we went; 2. The voyage; 3. St. Helena; 4. What Ascension looked like; 5. Ascension past and present; 6. Round about Garrison; 7. A night on the Clinker; 8. Change and check; 9. Mars Bay; 10. A Sunday scene; 11. The opposition of Mars; 12. The sea-shore and the rollers; 13. Green Mountain; 14. Sunday at the mountain; 15. Why we had only a gallon of water; 16. Trips from Garden Cottage; 17. Mars Bay without a cook; 18. Wide-awake fair; 19. Last days at Mars Bay; 20. Christmas in Garrison; 21. About the Kroomen; 22. Clinker Cemeteries; 23. Christmas holidays; 24. The Devil's riding school; 25. Homeward bound.

  4. Possessor Ascension in Dakota Sioux.

    ERIC Educational Resources Information Center

    Pinson, Thomas M.

    A study of Dakota Sioux presents evidence for Possessor Ascension. In this construction, a nominal that is semantically a possessor is syntactically not a constituent of the noun phrase but a constituent of the clause. The report first discusses the universal characterization of Possessor Ascension in the framework of relational grammar, and…

  5. Sponsorship transformation at Ascension Health.

    PubMed

    Sr Barbara A Moore

    2007-01-01

    Two Catholic health systems, the Daughters of Charity National Health System and the Sisters of St. Joseph Health System, came together to create St. Louis-based Ascension Health in 1999. A third organization, Carondelet Health System, then merged with Ascension Health in December 2002. Ascension Health is sponsored by four provinces of the Daughters of Charity, the Sisters of St. Joseph of Nazareth, and the Sisters of St. Joseph of Carondelet. Ascension Health operates according to a concept it calls "sponsorship of the whole," which has been defined as follows: "The sponsors of Ascension Health exercise canonical responsibility to ensure that the health ministry sustains and strengthens Catholic identity while expressing the charisms of the present and future sponsors. The sponsors act as stewards of Ascension Health's mission and resources, and commit, in partnership with others, to educate, influence, nurture, and develop the combined health ministry to further the healing ministry of Jesus." After several years of serving together on the Sponsors Council-and following much prayer, theological reflection, and in-depth discussion-the sponsors decided to accept the "Sponsorship of the Whole" document. The document challenges sponsors to open their hearts and arms to embrace all of Ascension Health's local health ministries. When Ascension Health was formed in November 1999, it was with the intention of adding laypeople to the Sponsors Council. In late 2005, the system created a work group to explore key areas pertinent to the appointment of lay members to the council. The Sponsors Council then engaged in a rigorous identification and selection process, after which, on July 1, 2006, it welcomed two lay members. Ascension Health will continue to develop its own preferred culture and identity. As the system's metamorphosis unfolds, personal conversion, a new way of relating to others, and changes in both attitudes and values will be necessary. PMID:17274573

  6. Geothermal potential of Ascension Island, south Atlantic. Phase I. Preliminary examination

    SciTech Connect

    Sibbett, B.S.; Neilson, D.L.; Ramsthaler, J.H.; Shane, M.K.

    1982-09-01

    A preliminary evaluation of the potential for an economic geothermal resource at Ascension Island was completed. It is concluded that there is a high potential for the presence of a geothermal resource under the Island. A conceptual plant has been designed assuming the resource potential located near Gannet Hill is developed. A 7% discounted payback of 5.9 years was calculated for the baseline geothermal plant. Geothermal development can be easily integrated into the Ascension Island power system in that a selection of small, portable, skid mounted, turn key power geothermal generating systems are commercially available. Geologic findings and plant analysis are summarized.

  7. A comparison of TEC fluctuations and scintillations at Ascension Island

    NASA Astrophysics Data System (ADS)

    Basu, S.; Groves, K. M.; Quinn, J. M.; Doherty, P.

    1999-11-01

    With increasing reliance on space-based platforms for global navigation and communication, concerns about the impact of ionospheric scintillation on these systems have become a high priority. Recently, the Air Force Research Laboratory (AFRL) performed amplitude scintillation measurements of L1 (1.575 MHz) signals from GPS satellites at Ascension Island (14.45° W, 7.95° S; magnetic latitude 16° S) during February-April, 1998, to compare amplitude scintillations with fluctuations of the total electron content (TEC). Ascension Island is located in the South Atlantic under the southern crest of the equatorial anomaly of F2 ionization where scintillations will be much enhanced during the upcoming solar maximum period. Ascension Island is included in the global network of the International GPS Service (IGS) and the GPS receivers in this network report the carrier to noise (C/N) ratio, the dual frequency carrier phase and pseudorange data at 30-s intervals. Such data with a sampling interval of 30 s were analyzed to determine TEC, the rate of change of TEC (ROT) and also ROTI, defined as the standard deviation of ROT. The spatial scale of ROTI, sampled at 30 s interval, will correspond to 6 km when the vector sum of the ionospheric projection of the satellite velocity and the irregularity drift orthogonal to the propagation path is of the order of 100 m/s. On the other hand, the scale-length of the amplitude scintillation index corresponds to the Fresnel dimension which is about 400 m for the GPS L1 frequency and an ionospheric height of 400 km. It is shown that, in view of the co-existence of large and small scale irregularities in equatorial irregularity structures, during the early evening hours, and small magnitude of irregularity drifts, ROTI measurements can be used to predict the presence of scintillation causing irregularities. The quantitative relationship between ROTI and S4, however, varies considerably due to variations of the ionospheric projection of the

  8. Geothermal Gradient Drilling and Measurements Ascension Island, South Atlantic Ocean

    SciTech Connect

    Sibbett, B.S.; Nielson, D.L.; Adams, M.C.

    1984-07-01

    This technical report on the Phase II geothermal exploration of Ascension Island documents the data collected during thermal gradient drilling and the subsequent thermal and fluid chemical investigations. It also documents the completion of the Phase II exploration strategy which was proposed at the end of the Phase I--Preliminary Examination of Ascension Island. The thermal gradient drilling resulted in seven holes which range from 206 to 1750 ft (53-533 m) deep, with a cumulative footage of 6563 ft (2000 m). The drilling procedure and the problems encountered during the drilling have been explained in detail to provide information valuable for any subsequent drilling program on the island. In addition, the subsurface geology encountered in the holes has been documented and, where possible, correlated with other holes or the geology mapped on the surface of the island. Temperatures measured in the holes reach a maximum of 130 F (54.4 C) at 1285 ft (391.7 m) in hole GH-6. When the temperatures of all holes are plotted against elevation, the holes can be classed into three distinct groups, those which have no thermal manifestations, those with definite geothermal affinities, and one hole which is intermediate between the other two. From consideration of this information, it is clear that the highest geothermal potential on the island is in the Donkey Flat area extending beneath Middleton Ridge, and in the Cricket Valley area. Because of the greater drilling depths and the remote nature of the Cricket Valley area, it is recommended that future exploration concentrate in the area around Middleton Ridge.

  9. Strategies for power scaling VECSELs

    NASA Astrophysics Data System (ADS)

    Wang, Tsuei-Lian; Kaneda, Yushi; Hader, Jörg; Moloney, Jerome V.; Kunert, Bernardette; Stolz, Wolfgang; Koch, Stephan W.

    2012-03-01

    Strategies for power scaling VECSELs, including improving thermal management, increasing the quantum well gain/micro-cavity detuning that increases the threshold but increases roll-over temperature, and double-passing the excess pump via reflection from a metalized reflector at the back of a transparent distributed Bragg reflector (DBR) were studied. The influence of the heat spreader thickness and the pump profile on the temperature rise inside the active region was investigated using commercial finite element analysis software. Improvement was observed in optical efficiency of the VECSEL devices with a transparent DBR by double passing the pump light. Higher dissipated power at maximum output power was found in devices with larger spectral detuning between the quantum well gain and the micro-cavity detuning.

  10. Global power: Markets and strategies

    SciTech Connect

    Poirer, J.L.

    1998-07-01

    The author will first present an updated view of the global power market activity, including opportunities in power generation, transmission and distribution. This will include a review of the trends in closings and transaction flowed by type of activity and geographic area. Estimates will be based on Hagler Bailly's comprehensive database on global power transactions and project announcements. The firm has also worked with dozens of global power companies since 1990. Second, the author will review trends in terms of regulatory changes, project cost trends, developers' project experiences, and financing issues. This systematic review will be the foundation for projection of future market activity (e.g., number of closing by type of project through 2000). A forecast of future greenfield and privatization activity will be provided and the key markets will be highlighted. Third, the author will present an updated view of the competition in the global power market (including the various types of competitors and changes in their respective market posture). Finally, the author will discuss the various types of strategies and business models that are followed by key global power players.

  11. Deploying the NASA Meter Class Autonomous Telescope (MCAT) on Ascension Island

    NASA Technical Reports Server (NTRS)

    Lederer, S. M.; Pace, L.; Hickson, P.; Cowardin, H. M.; Frith, J.; Buckalew, B.; Glesne, T.; Maeda, R.; Douglas, D.; Nishimoto, D.

    2015-01-01

    NASA has successfully constructed the 1.3m Meter Class Autonomous Telescope (MCAT) facility on Ascension Island in the South Atlantic Ocean. MCAT is an optical telescope designed specifically to collect ground-based data for the statistical characterization of orbital debris ranging from Low Earth Orbit (LEO) through Middle Earth Orbits (MEO) and beyond to Geo Transfer and Geosynchronous Orbits (GTO/GEO). The location of Ascension Island has two distinct advantages. First, the near-equatorial location fills a significant longitudinal gap in the Ground-based Electro-Optical Deep Space Surveillance (GEODSS) network of telescopes, and second, it allows access to objects in Low Inclination Low-Earth Orbits (LILO). The MCAT facility will be controlled by a sophisticated software suite that operates the dome and telescope, assesses sky and weather conditions, conducts all necessary calibrations, defines an observing strategy (as dictated by weather, sky conditions and the observing plan for the night), and carries out the observations. It then reduces the collected data via four primary observing modes ranging from tracking previously cataloged objects to conducting general surveys for detecting uncorrelated debris. Nightly observing plans, as well as the resulting text file of reduced data, will be transferred to and from Ascension, respectively, via a satellite connection. Post-processing occurs at NASA Johnson Space Center. Construction began in September, 2014 with dome and telescope installation occurring in April through early June, 2015. First light was achieved in June, 2015. Acceptance testing, full commissioning, and calibration of this soon-to-be fully autonomous system commenced in summer 2015. The initial characterization of the system from these tests is presented herein.

  12. Deploying the NASA Meter Class Autonomous Telescope (MCAT) on Ascension Island

    NASA Astrophysics Data System (ADS)

    Lederer, S.; Pace, L. F.; Hickson, P.; Glesne, T.; Cowardin, H. M.; Frith, J. M.; Buckalew, B.; Maeda, R.; Douglas, D.; Nishimoto, D.

    NASA has successfully constructed the 1.3m Meter Class Autonomous Telescope (MCAT) facility on Ascension Island in the South Atlantic Ocean. MCAT is an optical telescope designed specifically to collect ground-based data for the statistical characterization of orbital debris ranging from Low Earth Orbit (LEO) through Middle Earth Orbits (MEO) and beyond to Geo Transfer and Geosynchronous Orbits (GTO/GEO). The location of Ascension Island has two distinct advantages. First, the near-equatorial location fills a significant longitudinal gap in the Ground-based Electro-Optical Deep Space Surveillance (GEODSS) network of telescopes, and second, it allows access to objects in Low Inclination Low-Earth Orbits (LILO). The MCAT facility will be controlled by a sophisticated software suite that operates the dome and telescope, assesses sky and weather conditions, conducts all necessary calibrations, defines an observing strategy (as dictated by weather, sky conditions, and the observing plan for the night), and carries out the observations. It then reduces the collected data via four primary observing modes ranging from tracking previously cataloged objects to conducting general surveys for detecting uncorrelated debris. Nightly observing plans, as well as the resulting text file of reduced data, will be transferred to and from Ascension, respectively, via a satellite connection. Post-processing occurs at NASA Johnson Space Center. Construction began in September, 2014 with dome and telescope installation occurring in April through early June, 2015. First light was achieved in June, 2015. Acceptance testing, full commissioning, and calibration of this soon-to-be fully autonomous system commenced in summer 2015. The initial characterization of the system from these tests is presented herein.

  13. Space nuclear power: a strategy for tomorrow

    SciTech Connect

    Buden, D.; Angelo, J. Jr.

    1981-01-01

    Energy: reliable, portable, abundant and low cost will be a most critical factor, perhaps the sine qua non, for the unfolding of man's permanent presence in space. Space-based nuclear power, in turn, is a key technology for developing such space platforms and the transportation systems necessary to service them. A strategy for meeting space power requirements is the development of a 100-kW(e) nuclear reactor system for high earth orbit missions, transportation from Shuttle orbits to geosynchronous orbit, and for outer planet exploration. The component technology for this nuclear power plant is now underway at the Los Alamos National Laboratory. As permanent settlements are established on the Moon and in space, multimegawatt power plants will be needed. This would involve different technology similar to terrestrial nuclear power plants.

  14. Integrated Surface Power Strategy for Mars

    NASA Technical Reports Server (NTRS)

    Rucker, Michelle

    2015-01-01

    A National Aeronautics and Space Administration (NASA) study team evaluated surface power needs for a conceptual crewed 500-day Mars mission. This study had four goals: 1. Determine estimated surface power needed to support the reference mission; 2. Explore alternatives to minimize landed power system mass; 3. Explore alternatives to minimize Mars Lander power self-sufficiency burden; and 4. Explore alternatives to minimize power system handling and surface transportation mass. The study team concluded that Mars Ascent Vehicle (MAV) oxygen propellant production drives the overall surface power needed for the reference mission. Switching to multiple, small Kilopower fission systems can potentially save four to eight metric tons of landed mass, as compared to a single, large Fission Surface Power (FSP) concept. Breaking the power system up into modular packages creates new operational opportunities, with benefits ranging from reduced lander self-sufficiency for power, to extending the exploration distance from a single landing site. Although a large FSP trades well for operational complexity, a modular approach potentially allows Program Managers more flexibility to absorb late mission changes with less schedule or mass risk, better supports small precursor missions, and allows a program to slowly build up mission capability over time. A number of Kilopower disadvantages-and mitigation strategies-were also explored.

  15. Experimentally Determined Coordinates for Three MILS Hydrophones Near Ascension Island

    SciTech Connect

    Harben, P. E.; Hollfelder, J. R.; Rodgers, A. J.

    1999-11-19

    We conducted an airgun survey in the waters of Ascension Island in May 1999 to determine new locations and depths for three Missile Impact Location System (MILS) hydrophones (ASC23, ASC24, and ASC26) currently in use by the Prototype International Data Center (PIDC) and the National Data Center (NDC). The nominal and new locations are summarized in Table 1. Although not rigorous, errors in the new locations and depths are conservatively estimated to be less than 100 m. The hydrophones are either on or near the ocean bottom in all three cases. The new depths are consistent with the following: Direct-phase airgun arrivals; Bathymetry determined along the track of the ship used for this airgun survey; Reflected phases from the airgun data; and Depths given in the original hydrophone installation report.

  16. The NASA Meter Class Autonomous Telescope: Ascension Island

    NASA Technical Reports Server (NTRS)

    Lederer, S. M.; Stansbery, E. G.; Cowardin, H. M.; Kervin, P.; Hickson, P.

    2013-01-01

    smaller in size, has been operating in conjunction with this effort until recently in M.ron, Spain. With the M.ron site closing, a significant gap in longitude exists between the New Mexico and Diego Garcia sites. This longitudinal gap is well covered by placing a telescope on Ascension Island (7degrees 58'20" S, 14degrees 24'4"W), in the Atlantic Ocean. Ascension Island offers the benefits of both location and weather. The near equatorial location affords the opportunity to access under-sampled low-inclination orbits and new GEO longitudes, while simultaneously filling in the GEODSS longitudinal gap. Ascension Island is a volcanic, desert island, receiving only 7" of rain per year on average. With consistent trade winds blowing from the SSE direction off Africa, the combination of an island location with consistent winds will create the smooth laminar flow sought after by all astronomical sites, which creates stable atmospheric ('seeing') conditions. Finally, this low population island has minimal lighting, resulting in very dark skies, ideal for an observatory.

  17. The NASA Meter Class Autonomous Telescope: Ascension Island

    NASA Astrophysics Data System (ADS)

    Lederer, S.; Stansbery, E. G.; Cowardin, H. M.; Kervin, P.; Hickson, P.

    2013-09-01

    smaller in size, has been operating in conjunction with this effort until recently in M?ron, Spain. With the M?ron site closing, a significant gap in longitude exists between the New Mexico and Diego Garcia sites. This longitudinal gap is well covered by placing a telescope on Ascension Island (7deg 58' 20" S, 14deg 24' 4"W), in the Atlantic Ocean. Ascension Island offers the benefits of both location and weather. The near equatorial location affords the opportunity to access under-sampled low-inclination orbits and new GEO longitudes, while simultaneously filling in the GEODSS longitudinal gap. Ascension Island is a volcanic, desert island, receiving only 7" of rain per year on average. With consistent trade winds blowing from the SSE direction off Africa, the combination of an island location with consistent winds will create the smooth laminar flow sought after by all astronomical sites, which creates stable atmospheric (‘seeing') conditions. Finally, this low population island has minimal lighting, resulting in very dark skies, ideal for an observatory.

  18. The NASA Meter Class Autonomous Telescope: Ascension Island

    NASA Technical Reports Server (NTRS)

    Lederer, S. M.; Stansbery, E. G.; Cowardin, H. M.; Hickson, P.; Pace, L. F.; Abercromby, K. J.; Kervin, P. W.

    2013-01-01

    The Meter Class Autonomous Telescope (MCAT) is the newest optical sensor dedicated to NASA's mission to characterize the space debris environment. It is the successor to a series of optical telescopes developed and operated by the JSC Orbital Debris Program Office (ODPO) to monitor and assess the debris environment in (1) Low Earth Orbit (LEO), (2) Medium Earth Orbit (MEO), and (3) Geosynchronous Orbit (GEO), with emphasis on LEO and GEO altitudes. A joint NASA - Air Force Research Labs project, MCAT is a 1.3m optical telescope dedicated to debris research. Its optical path and sensor yield a large survey fence at the cutting edge of current detector performance. It has four primary operational observing modes, two of which were not computationally feasible a decade ago. Operations are supported by a sophisticated software suite that monitors clouds and weather conditions, and controls everything from data collection to dome rotation to processing tens of gigabytes of image data nightly. With fainter detection limits, precision detection, acquisition and tracking of targets, multi-color photometry, precision astrometry, automated re-acquisition capability, and the ability to process all data at the acquisition rate, MCAT is capable of producing and processing a volume and quality of data far in excess of any current (or prior) ODPO operations. This means higher fidelity population inputs and eliminating the multi-year backlog from acquisition-to-product typical of optical campaigns. All of this is possible given a suitable observing location. Ascension Island offers numerous advantages. As a British overseas territory with a US Air Force base presence, the necessary infrastructure and support already exists. It is located mid-way between Brazil and Africa at 7.93S latitude and 14.37 W longitude. With the Ground-based Electro-Optical Deep Space Surveillance (GEODSS) asset in Moron, Spain shutting down, this presents access to the sky from a unique latitude

  19. Powering nanorobotic devices: challenges and future strategies

    NASA Astrophysics Data System (ADS)

    Sankar, Krishna Moorthi

    2014-04-01

    Nanotechnology, even after 55 years since its foundation (1959 Richard Feynman's speech - `There is lot of space in the bottom'), is still in its infancy. However, of late, there has been a large increase in the research being done in this field in many prominent Universities and Research institutions across the globe. Nanorobotics is the combination of Nanotechnology and the science of Robotics, to create robots that are only a few nanometres (10-9 metres) in size. Nanobots are yet to be made. But with the current pace of ongoing researches, scientists predict that nanobots will be made a reality by next ten years. The main proposed function of nanobots is to use them in the medical field to interact with cells or intra-cellular substances and prevent or reverse structural and genetical problems and diseases. One of the major challenges faced while creating a nanobot to travel through human body is to power it. Nanobots would require a very small yet highly potential source of energy. There are many hypothesised energy sources for nanobots which are either already available within the human body naturally or which are to be supplied externally. But, all of these energy sources pose a few challenges which need to be addressed if they are to be used to power nanobots. These challenges can be overcome using a number of strategies that can be used to make an economically, ecologically and medically viable energy source.

  20. Power Subscription Strategy: Administrator`s Record of Decision.

    SciTech Connect

    United States. Bonneville Power Administration

    1998-12-01

    The Bonneville Power Administration (BPA) has decided to adopt a Power Subscription Strategy for entering into new power sales contracts with its Pacific Northwest customers. The Strategy equitably distributes the electric power generated by the Federal Columbia River Power System (FCRPS) within the framework of existing law. The Power Subscription Strategy addresses the availability of power; describes power products; lays out strategies for pricing, including risk management; and discusses contract elements. In proceeding with this Subscription Strategy, BPA is guided by and committed to the Fish and Wildlife funding Principles for the BPA announced by the Vice President of the US in September 1998. This Record of Decision (ROD) addresses the issues raised by commenters who responded to BPA`s Power Subscription Strategy Proposal during and after the comment period that began with the release of the Proposal on September 18, 1998. The ROD is organized in approximately the same way as the Proposal and the Power Subscription Strategy that BPA developed based on the comments received. Abbreviations of party names used in citations appear in the section just preceding this introduction; a list of all the commenters follows the text of the ROD.

  1. PAQ Types and Power Strategies Used in Intimate Relationships.

    ERIC Educational Resources Information Center

    Falbo, Toni

    1982-01-01

    Examined kinds of power strategies used by masculine, feminine, androgynous, and undifferentiated people in their intimate relationships. Androgynous people reported using primarily bilateral strategies, such as persuasion. Undifferentiated people reported using primarily unilateral strategies, such as doing what they wanted, regardless of their…

  2. An evolutionary strategy for space nuclear power

    NASA Astrophysics Data System (ADS)

    Bennett, Gary L.

    1996-03-01

    A number of exciting mission opportunities are being considered for the 21st century, including (1) advanced robotic science missions to the outer planets and beyond; (2) advanced space transportation systems; and (3) human exploration of the Moon and Mars. Several of these missions will require some form of nuclear power; however, it is clear that current budgetary constraints preclude developing many different types of space nuclear power systems. This paper reviews the specific civil space missions which have been identified, the power levels and lifetimes required, and the technologies available. From this an evolutionary space nuclear power program is developed which builds upon the experience of radioisotope thermoelectric generators, improved static and dynamic isotope power systems, and space nuclear reactors. It is strongly suggested that not only does this approach make technical and budgetary sense but that it is consistent with the normal development of new technologies.

  3. Purchased power is not a riskless strategy

    SciTech Connect

    Foltz, D.A.; Malko, J.R.; Pumilia, G.J.; Purvenas, T.J.

    1994-12-01

    Purchased power may allow utilities to delay or eliminate plant construction, but our review of credit agencies and impacts on bond yields indicates added risk to the utility that enters into purchased power commitments. The electric utility industry currently is in a state of flux. The traditional relationship of a vertically integrated electric utility providing generation, transmission and distribution of electric power to its customers has changed. Through the Public Utilities Regulatory Policies Act of 1978 (PURPA) and the National Energy Policy Act of 1992 (EPAct), electric utilities now face business competition in electric generation and transmission segments. While the precise risk implications associated with the gradual deregulations of the electric utility industry are still uncertain, electric utilities have begun to feel the negative impact of purchased power through credit rating agency downgradings. The primary purposes of this article are: (1) to highlight the increase in investment risk caused by purchased power contracts in order to demonstrate that purchased power is not a riskless alternative to building, and (2) to attempt to quantify the added cost of purchased power. When discussing the risk implications of purchased power, it is important to understand how the risk of a firm is evaluated. The investment risk of a firm is composed of business risk and financial risk. The business risk of a firm includes all factors that affect its pre-tax operating income (EBIT). The financial risk of a firm is caused by the use of leverage, or borrowed funds, in its capital structure. Purchased power can increase both business and financial risk of an electric utility.

  4. Powerful and Easy Research Strategies Workshop.

    ERIC Educational Resources Information Center

    Whitfield, Gary W.

    Many social workers are anxious about the use of evaluation techniques and are particularly reticent about using statistical research. Strategies for understanding the steps involved in integrating practice and evaluation in a school social work setting, an appreciation for the need of evaluation, and knowledge of various resources on conducting…

  5. Optimal dispatch strategy in remote hybrid power systems

    SciTech Connect

    Barley, C.D.; Winn, C.B.

    1996-10-01

    For small villages in developing countries, local stand-alone power systems are often more cost-effective than utility grid extension. Various combinations of wind turbine generators, photovoltaic arrays, diesel gensets, and batteries - remote hybrid power systems - may be preferred to diesel-only systems. Dispatch strategy is the aspect of control strategy that pertains to energy flows among components. In systems with both batteries and diesel genset(s), dispatch affects the life-cycle cost through both the fuel usage and the battery life. In this study, dispatch strategies are compared using (1) an analysis of cost trade-offs, (2) a simple, quasi-steady-state time-series model, and finally (3) HYBRID2, a more sophisticated stochastic time-series model. An idealized predictive dispatch strategy, based on assumed perfect knowledge of future load and wind conditions, is developed and used as a benchmark in evaluating simple, non-predictive strategies. The results illustrate the nature of the optimal strategy and indicate that one of two simple diesel dispatch strategies - either load-following or full power for a minimum run time - can, in conjunction with the frugal use of stored energy (the Frugal Discharge Strategy), be virtually as cost-effective as the Ideal Predictive Strategy. The optimal choice of these two simple charging strategies is correlated to three dimensionless parameters, yielding a generalized dispatch design chart for an important class of systems. 30 refs., 17 figs., 3 tabs.

  6. Constructing Cultures of Non-Violence: The Peace Power! Strategy.

    ERIC Educational Resources Information Center

    Mattaini, Mark A.; Addams, Jane

    2001-01-01

    This article presents an alternative approach for reducing violence in schools: the development of evidence-based tools that can be used in existing networks to structure systemic changes. The PEACE POWER strategy emphasizes four practices: recognize contributions and successes, act with respect, share power to build community, and make peace.…

  7. Optimal generator bidding strategies for power and ancillary services

    NASA Astrophysics Data System (ADS)

    Morinec, Allen G.

    As the electric power industry transitions to a deregulated market, power transactions are made upon price rather than cost. Generator companies are interested in maximizing their profits rather than overall system efficiency. A method to equitably compensate generation providers for real power, and ancillary services such as reactive power and spinning reserve, will ensure a competitive market with an adequate number of suppliers. Optimizing the generation product mix during bidding is necessary to maximize a generator company's profits. The objective of this research work is to determine and formulate appropriate optimal bidding strategies for a generation company in both the energy and ancillary services markets. These strategies should incorporate the capability curves of their generators as constraints to define the optimal product mix and price offered in the day-ahead and real time spot markets. In order to achieve such a goal, a two-player model was composed to simulate market auctions for power generation. A dynamic game methodology was developed to identify Nash Equilibria and Mixed-Strategy Nash Equilibria solutions as optimal generation bidding strategies for two-player non-cooperative variable-sum matrix games with incomplete information. These games integrated the generation product mix of real power, reactive power, and spinning reserve with the generators's capability curves as constraints. The research includes simulations of market auctions, where strategies were tested for generators with different unit constraints, costs, types of competitors, strategies, and demand levels. Studies on the capability of large hydrogen cooled synchronous generators were utilized to derive useful equations that define the exact shape of the capability curve from the intersections of the arcs defined by the centers and radial vectors of the rotor, stator, and steady-state stability limits. The available reactive reserve and spinning reserve were calculated given a

  8. An evolution strategy for lunar nuclear surface power

    NASA Technical Reports Server (NTRS)

    Mason, Lee S.

    1992-01-01

    The production and transmission of electric power for a permanently inhabited lunar base poses a significant challenge which can best be met through an evolution strategy. Nuclear systems offer the best opportunity for evolution in terms of both life and performance. Applicable nuclear power technology options include isotope systems (either radioisotope thermoelectric generators or dynamic isotope power systems) and reactor systems with either static (thermoelectric or thermionic) or dynamic (Brayton, Stirling, Rankine) conversion. A power system integration approach that takes evolution into account would benefit by reduced development and operations cost, progressive flight experience, and simplified logistics, and would permit unrestrained base expansion. For the purposes of defining a nuclear power system evolution strategy, the lunar base development shall consist of four phases: precursor, emplacement, consolidation, and operations.

  9. Power-amplifying strategy in vibration-powered energy harvesters

    NASA Astrophysics Data System (ADS)

    Ma, Pyung Sik; Kim, Jae Eun; Kim, Yoon Young

    2010-04-01

    A new cantilevered piezoelectric energy harvester (PEH) of which the additional lumped mass is connected to a harmonically oscillating base through an elastic foundation is proposed for maximizing generated power and enlarging its frequency bandwidth. The base motion is assumed to provide a given acceleration level. Earlier, a similar energy harvester employing the concept of the dynamic vibration absorber was developed but the mechanism of the present energy harvester is new because it incorporates a mass-spring system in addition to a conventional cantilevered piezoelectric energy harvesting beam with or without a tip mass. Consequently, the proposed energy harvester actually forms a two-degree-of-freedom system. It will be theoretically shown that the output power can be indeed substantially improved if the fundamental resonant frequencies of each of the two systems in the proposed energy harvester are simultaneously tuned as closely as possible to the input excitation frequency and also if the mass ratio of a piezoelectric energy harvesting beam to the lumped mass is adjusted below a certain value. The performance of the proposed energy harvester is checked by numerical simulation.

  10. Isotope and methane dynamics above and below the Trade Wind Inversion at Ascension Island using UAVs

    NASA Astrophysics Data System (ADS)

    Brownlow, R.; Lowry, D.; Nisbet, E. G.; Fisher, R. E.; France, J.; Lanoisellé, M.; Thomas, R.; Richardson, T.; Greatwood, C.; Freer, J. E.; MacKenzie, A. R.

    2015-12-01

    Ascension Island (8oS, 14 oW) is a South Atlantic background site for atmospheric measurement. Royal Holloway, in collaboration with the UK Met Office, installed a Picarro 1301 CRDS in 2010 for continuous methane monitoring. This has high precision and accuracy, with a 6-gas calibration and target suite, to measure long term methane mole fraction. Regular flask sampling is also carried out for NOAA and RHUL (co-located), to measure δ13CCH4 isotopic trends.Ascension Island experiences near-constant SE Trade winds below the Trade Wind Inversion (TWI), with air from the remote S. Atlantic. In flask samples and in continuous monitoring at the Airhead location, atmospheric methane mole fraction has been increasing since 2007 whilst the δ13CCH4 isotope record has shifted to more depleted values. Above the normally well-defined TWI (1200 - 1800m altitude), variable tropical air masses pass over Ascension. This air last mixed with the boundary layer over Africa or South America. Field work undertaken in September 2014 and July 2015, in collaboration with U. Bristol and U. Birmingham, using UAVs (octocopters) collected samples with Tedlar bags or aluminium flasks from different heights above and below the TWI. The maximum altitude reached was 2700masl. Sample bags were immediately analysed on Ascension for CH4 mole fraction using the Picarro CRDS and subsequently analysed at RHUL for δ13CCH4 using continuous-flow gas chromatography/isotope-ratio mass spectrometry (CF-GC/IRMS). The TWI was clearly identified by an increase in CH4 mole fraction above the TWI. Back trajectory analysis was used to distinguish the origins of the air masses, with air above showing inputs from the land surfaces of equatorial and southern Africa, and from southern S. America.The campaigns have extended the envelope of altitudes accessed by micro-UAVs for atmospheric science, demonstrating their utility for probing the remote free troposphere and for penetrating the TWI. Sampling at Ascension is

  11. The Ascension Island hydroacoustic experiment: purpose, data set features and plans for future analysis

    SciTech Connect

    Harben, P E; Rock, D; Rodgers, A J

    1999-07-23

    Calibration of hydroacoustic and T-phase stations for Comprehensive Nuclear-Test-Ban Treaty (CTBT) monitoring will be an important element in establishing new operational stations and upgrading existing stations. Calibration of hydroacoustic stations is herein defined as precision location of the hydrophones and determination of the amplitude response from a known source energy. T-phase station calibration is herein defined as a determination of station site attenuation as a function of frequency, bearing, and distance for known impulsive energy sources in the ocean. To understand how to best conduct calibration experiments for both hydroacoustic and T-phase stations, an experiment was conducted in May, 1999 at Ascension Island in the South Atlantic Ocean. The experiment made use of a British oceanographic research vessel and collected data that will be used for CTBT issues and for fundamental understanding of the Ascension Island volcanic edifice.

  12. Isotopic composition of lead and strontium from Ascension and Gough Islands

    USGS Publications Warehouse

    Gast, P.W.; Tilton, G.R.; Hedge, C.

    1964-01-01

    Isotopic composition of lead and strontium has been determined in a series of rock samples from two islands on the Mid-Atlantic Ridge. Both inter-and intra-island variations exist in the abundance of radiogenic isotopes of both elements. Lead from basalt of Ascension Island has a Pb206-Pb 204 ratio of 19.5, while the corresponding ratio at Gough Island is only 18.4. The Pb208-Pb204 ratios from the two islands do not differ. Conversely, strontium from basalt of Ascension Island is less radiogenic than that from Gough Island basalts. The trachytes of both islands have lead and strontium that is more radiogenic than that found in the basalts. The inter-island differences indicate the existence of regional variations in the uranium-lead and rubidium-strontium ratios of the upper mantle source of these rocks and show that isotope compositions are a means for investigating chemical heterogeneities in the mantle.

  13. Peace Power for Adolescents: Strategies for a Culture of Nonviolence.

    ERIC Educational Resources Information Center

    Mattaini, Mark A.

    Recent school shootings are only one symptom of a greater problem--a toxic social environment that breeds isolation and rage among children. This book looks at the wide range of risk factors and indicators for violence and translates the findings into an effective prevention and intervention system. The Peace Power strategy is based on four core…

  14. A comparison between the precession-nutation variations in right ascension referred to the CIO and the equinox

    NASA Astrophysics Data System (ADS)

    Husar, Ladislav

    2013-01-01

    The article analyzes the precession-nutation variations in right ascension of stars after the introduction Celestial Intermediate Origin (CIO) as a new origin of the right ascensions. It points out that changes in right ascension depend not only on the motion of the origin, but also on the changes of the pole and hour circles, depending on the position of stars. This explains the apparent paradox that, for certain groups of stars, despite the almost complete elimination of the precession and nutation motion of the CIO on the equator, the magnitude of the variations in right ascension related to the CIO can exceed the magnitude of the classic variations referred to the equinox.

  15. Recent sea beam mapping of Ascension-Monterey Submarine Canyon System

    SciTech Connect

    Greene, H.G. )

    1990-06-01

    Extensive Sea Beam and Bathymetric Swatch Survey System (BS{sup 3}) data covering the Ascension-Monterey Submarine Canyon system and adjoining areas and canyons were collected offshore central California. Many discovered geomorphological features lead to significant new geologic conclusions about the formation and processes of submarine canyons in general and disclose unique sedimentary and tectonic features of the Ascension-Monterey Canyon system. The highly detailed bathymetric maps constructed from the Sea Beam data indicate that the seafloor topographic pattern is influenced by sedimentary and tectonic processes; both remain active along the central California margin. Interpretations of MOAA composite maps, final raw Sea Beam bathymetric maps, and three-dimensional physiographic renditions from bathymetric data indicate a diverse and complex geomorphology for the Ascension-Monterey Submarine Canyon system and adjoining region. Five distinct geomorphologic provinces and four well-defined geographic areas are mapped. Canyons cut by faults and canyon walls actively undergoing mass wasting are prominently displayed in the Sea Beam data. Sedimentary processes illustrating canyon channel capture and the formation of extensive mega-sedimentary wave fields where the canyons debouch onto the abyssal plain are spectacularly well defined. This new tool of seafloor mapping is contributing significant data for the geological interpretation of continental margins and seafloor in the world's oceans.

  16. Amnestus mendeli sp. n., the first burrower bug species (Hemiptera: Heteroptera: Cydnidae) recorded on Ascension Island, central Atlantic Ocean.

    PubMed

    Lis, Jerzy A; Lis, Barbara

    2016-01-01

    A new species of the genus Amnestus Dallas, 1851, Amnestus mendeli, is described from the cloud zone of Green Mountain, Ascension Island, and compared with its closest relatives, the Brazilian Amnestus lenkoi Froeschner, 1975 and Amnestus pequinus Froeschner, 1975. It is the first representative of the family Cydnidae recorded on the island thus far. The species is presumed to be an introduction from the Americas, but the hypothesis that it might be endemic to Ascension Island is also not excluded. PMID:27395576

  17. Robust multivariable strategy and its application to a powered wheelchair.

    PubMed

    Nguyen, Nghia; Nguyen, Hung T; Su, Steven

    2009-01-01

    The paper proposes a systematic robust multivariable control strategy based on combination of systematic triangularization technique and robust control strategies. Two design stages are required. In the first design stage, multivariable control problem is reduced into a series of scalar control problems via triangularization technique. For each specific scalar system, two advanced control strategies are proposed and implemented in the second design stage. The first one is based on Model Predictive Control, which is an iterative, finite horizon optimization procedure. The second control strategy is known as Neuro-Sliding Mode Control, which integrates Sliding Mode Control (SMC) and Neural Network Design to achieve both chattering-free and system robustness. Real-time implementation on a powered wheelchair system confirms that robustness and desired performance of a multivariable system under model uncertainties and unknown external disturbances can indeed be achieved by the combination of triangularization technique and Neuro-Sliding Mode Control. PMID:19963948

  18. Radioisotope-based Nuclear Power Strategy for Exploration Systems Development

    SciTech Connect

    Schmidt, George R.; Houts, Michael G.

    2006-01-20

    Nuclear power will play an important role in future exploration efforts. Its benefits pertain to practically all the different timeframes associated with the Exploration Vision, from robotic investigation of potential lunar landing sites to long-duration crewed missions on the lunar surface. However, the implementation of nuclear technology must follow a logical progression in capability that meets but does not overwhelm the power requirements for the missions in each exploration timeframe. It is likely that the surface power infrastructure, particularly for early missions, will be distributed in nature. Thus, nuclear sources will have to operate in concert with other types of power and energy storage systems, and must mesh well with the power architectures envisioned for each mission phase. Most importantly, they must demonstrate a clear advantage over other non-nuclear options (e.g., solar power, fuel cells) for their particular function. This paper describes a strategy that does this in the form of three sequential system developments. It begins with use of radioisotope generators currently under development, and applies the power conversion technology developed for these units to the design of a simple, robust reactor power system. The products from these development efforts would eventually serve as the foundation for application of nuclear power systems for exploration of Mars and beyond.

  19. Dyadic Power Profiles: Power-Contingent Strategies for Value Creation in Negotiation

    ERIC Educational Resources Information Center

    Olekalns, Mara; Smith, Philip Leigh

    2013-01-01

    Using a simulated employment negotiation, we tested the conditional relationships among dyadic power profiles (symmetric high, symmetric low, and asymmetric), the choice and sequencing of strategies, and value creation. We showed that negotiators in symmetric high, symmetric low, and asymmetric power dyads took distinctly different paths to value…

  20. Synergistic Catalysis: A Powerful Synthetic Strategy for New Reaction Development

    PubMed Central

    Allen, Anna E.; MacMillan, David W. C.

    2012-01-01

    Synergistic catalysis is a synthetic strategy wherein both the nucleophile and the electrophile are simultaneously activated by two separate and distinct catalysts to afford a single chemical transformation. This powerful catalysis strategy leads to several benefits, specifically synergistic catalysis can (i) introduce new, previously unattainable chemical transformations, (ii) improve the efficiency of existing transformations, and (iii) create or improve catalytic enantioselectivity where stereocontrol was previously absent or challenging. This perspective aims to highlight these benefits using many of the successful examples of synergistic catalysis found in the literature. PMID:22518271

  1. Strategies for Radiation Hardness Testing of Power Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Soltis, James V. (Technical Monitor); Patton, Martin O.; Harris, Richard D.; Rohal, Robert G.; Blue, Thomas E.; Kauffman, Andrew C.; Frasca, Albert J.

    2005-01-01

    Plans on the drawing board for future space missions call for much larger power systems than have been flown in the past. These systems would employ much higher voltages and currents to enable more powerful electric propulsion engines and other improvements on what will also be much larger spacecraft. Long term human outposts on the moon and planets would also require high voltage, high current and long life power sources. Only hundreds of watts are produced and controlled on a typical robotic exploration spacecraft today. Megawatt systems are required for tomorrow. Semiconductor devices used to control and convert electrical energy in large space power systems will be exposed to electromagnetic and particle radiation of many types, depending on the trajectory and duration of the mission and on the power source. It is necessary to understand the often very different effects of the radiations on the control and conversion systems. Power semiconductor test strategies that we have developed and employed will be presented, along with selected results. The early results that we have obtained in testing large power semiconductor devices give a good indication of the degradation in electrical performance that can be expected in response to a given dose. We are also able to highlight differences in radiation hardness that may be device or material specific.

  2. Diversity Strategies for Nuclear Power Plant Instrumentation and Control Systems

    SciTech Connect

    Wood, Richard Thomas; Belles, Randy; Cetiner, Mustafa Sacit; Holcomb, David Eugene; Korsah, Kofi; Loebl, Andy; Mays, Gary T; Muhlheim, Michael David; Mullens, James Allen; Poore III, Willis P; Qualls, A L; Wilson, Thomas L; Waterman, Michael E.

    2010-02-01

    This report presents the technical basis for establishing acceptable mitigating strategies that resolve diversity and defense-in-depth (D3) assessment findings and conform to U.S. Nuclear Regulatory Commission (NRC) requirements. The research approach employed to establish appropriate diversity strategies involves investigation of available documentation on D3 methods and experience from nuclear power and nonnuclear industries, capture of expert knowledge and lessons learned, determination of best practices, and assessment of the nature of common-cause failures (CCFs) and compensating diversity attributes. The research described in this report does not provide guidance on how to determine the need for diversity in a safety system to mitigate the consequences of potential CCFs. Rather, the scope of this report provides guidance to the staff and nuclear industry after a licensee or applicant has performed a D3 assessment per NUREG/CR-6303 and determined that diversity in a safety system is needed for mitigating the consequences of potential CCFs identified in the evaluation of the safety system design features. Succinctly, the purpose of the research described in this report was to answer the question, 'If diversity is required in a safety system to mitigate the consequences of potential CCFs, how much diversity is enough?' The principal results of this research effort have identified and developed diversity strategies, which consist of combinations of diversity attributes and their associated criteria. Technology, which corresponds to design diversity, is chosen as the principal system characteristic by which diversity criteria are grouped to form strategies. The rationale for this classification framework involves consideration of the profound impact that technology-focused design diversity provides. Consequently, the diversity usage classification scheme involves three families of strategies: (1) different technologies, (2) different approaches within the same

  3. Power management strategy for vehicular-applied hybrid fuel cell/battery power system

    NASA Astrophysics Data System (ADS)

    Li, Xiangjun; Xu, Liangfei; Hua, Jianfeng; Lin, Xinfan; Li, Jianqiu; Ouyang, Minggao

    In this paper, a control strategy for a hybrid PEM (proton exchange membrane) fuel cell/BES (battery energy system) vehicular power system is presented. The strategy, based on fuzzy logic control, incorporates the slow dynamics of fuel cells and the state of charge (SOC) of the BES. Fuel cell output power was determined according to the driving load requirement and the SOC, using fuzzy dynamic decision-making and fuzzy self-organizing concepts. An analysis of the simulation results was conducted using Matlab/Simulink/Stateflow software in order to verify the effectiveness of the proposed control strategy. It was confirmed that the control scheme can be used to improve the operational efficiency of the hybrid power system.

  4. Maximum wind energy extraction strategies using power electronic converters

    NASA Astrophysics Data System (ADS)

    Wang, Quincy Qing

    2003-10-01

    This thesis focuses on maximum wind energy extraction strategies for achieving the highest energy output of variable speed wind turbine power generation systems. Power electronic converters and controls provide the basic platform to accomplish the research of this thesis in both hardware and software aspects. In order to send wind energy to a utility grid, a variable speed wind turbine requires a power electronic converter to convert a variable voltage variable frequency source into a fixed voltage fixed frequency supply. Generic single-phase and three-phase converter topologies, converter control methods for wind power generation, as well as the developed direct drive generator, are introduced in the thesis for establishing variable-speed wind energy conversion systems. Variable speed wind power generation system modeling and simulation are essential methods both for understanding the system behavior and for developing advanced system control strategies. Wind generation system components, including wind turbine, 1-phase IGBT inverter, 3-phase IGBT inverter, synchronous generator, and rectifier, are modeled in this thesis using MATLAB/SIMULINK. The simulation results have been verified by a commercial simulation software package, PSIM, and confirmed by field test results. Since the dynamic time constants for these individual models are much different, a creative approach has also been developed in this thesis to combine these models for entire wind power generation system simulation. An advanced maximum wind energy extraction strategy relies not only on proper system hardware design, but also on sophisticated software control algorithms. Based on literature review and computer simulation on wind turbine control algorithms, an intelligent maximum wind energy extraction control algorithm is proposed in this thesis. This algorithm has a unique on-line adaptation and optimization capability, which is able to achieve maximum wind energy conversion efficiency through

  5. T-Phase Observations from the May 1999 Ascension Island Experiment

    SciTech Connect

    Rodgers, A; Harben, P

    2000-07-19

    The Comprehensive Nuclear-Test-Ban Treaty (CTBT) specifies that an International Monitoring System (IMS) will be used to detect and locate disturbances that could be related to nuclear testing. In order to monitor disturbances in and near the world's oceans, the IMS will rely on a network of 11 hydroacoustic stations. This hydroacoustic network will be composed of 6 hydrophone stations and 5 T-phase seismic stations. The hydrophone stations will record pressure variations in the ocean. The T-phase stations will record the seismic waves in the solid earth that are excited when an hydroacoustic wave strikes an island or continental margin. The coupling of hydroacoustic-to-seismic energy for the purpose of CTBT monitoring is currently an active area of research. We report observations of hydroacoustic waves and their conversion to seismic waves (T-waves) at the volcanic edifice of Ascension Island. Earthquakes to the south of Ascension Island were recorded by International Monitoring System hydrophones and temporary seismic stations deployed on Ascension Island by LLNL. The hydrophone recordings are rich in high frequency (10-40 Hz) energy. However, the converted seismic waves (T-waves) are dominated by much lower frequencies (2-8 Hz). The T-waves demonstrate amplitude and travel time variations on the Island. We performed two-dimensional finite difference simulations to determine if the amplitude variability is the result of conversion along the complex bathymetry of the island and subsequent propagation to the station or a site effect. These observations suggest that the T-phase stations of the IMS may be useful for detecting and locating events in support of the CTBT provided that T-phase travel times are appropriately calibrated. However on volcanic islands, event identification based on T-phase data, which relies on high frequencies, may be inhibited by strong attenuation and low signal-to-noise.

  6. Wake Mitigation Strategies for Optimizing Wind Farm Power Production

    NASA Astrophysics Data System (ADS)

    Dilip, Deepu; Porté-Agel, Fernando

    2016-04-01

    Although wind turbines are designed individually for optimum power production, they are often arranged into groups of closely spaced turbines in a wind farm rather than in isolation. Consequently, most turbines in a wind farm do not operate in unobstructed wind flows, but are affected by the wakes of turbines in front of them. Such wake interference significantly reduces the overall power generation from wind farms and hence, development of effective wake mitigation strategies is critical for improving wind farm efficiency. One approach towards this end is based on the notion that the operation of each turbine in a wind farm at its optimum efficiency might not lead to optimum power generation from the wind farm as a whole. This entails a down regulation of individual turbines from its optimum operating point, which can be achieved through different methods such as pitching the turbine blades, changing the turbine tip speed ratio or yawing of the turbine, to name a few. In this study, large-eddy simulations of a two-turbine arrangement with the second turbine fully in the wake of the first are performed. Different wake mitigation techniques are applied to the upstream turbine, and the effects of these on its wake characteristics are investigated. Results for the combined power from the two turbines for each of these methods are compared to a baseline scenario where no wake mitigation strategies are employed. Analysis of the results shows the potential for improved power production from such wake control methods. It should be noted, however, that the magnitude of the improvement is strongly affected by the level of turbulence in the incoming atmospheric flow.

  7. Fault Diagnosis Strategies for SOFC-Based Power Generation Plants.

    PubMed

    Costamagna, Paola; De Giorgi, Andrea; Gotelli, Alberto; Magistri, Loredana; Moser, Gabriele; Sciaccaluga, Emanuele; Trucco, Andrea

    2016-01-01

    The success of distributed power generation by plants based on solid oxide fuel cells (SOFCs) is hindered by reliability problems that can be mitigated through an effective fault detection and isolation (FDI) system. However, the numerous operating conditions under which such plants can operate and the random size of the possible faults make identifying damaged plant components starting from the physical variables measured in the plant very difficult. In this context, we assess two classical FDI strategies (model-based with fault signature matrix and data-driven with statistical classification) and the combination of them. For this assessment, a quantitative model of the SOFC-based plant, which is able to simulate regular and faulty conditions, is used. Moreover, a hybrid approach based on the random forest (RF) classification method is introduced to address the discrimination of regular and faulty situations due to its practical advantages. Working with a common dataset, the FDI performances obtained using the aforementioned strategies, with different sets of monitored variables, are observed and compared. We conclude that the hybrid FDI strategy, realized by combining a model-based scheme with a statistical classifier, outperforms the other strategies. In addition, the inclusion of two physical variables that should be measured inside the SOFCs can significantly improve the FDI performance, despite the actual difficulty in performing such measurements. PMID:27556472

  8. The Acceptance Strategy for Nuclear Power Plant In Indonesia

    NASA Astrophysics Data System (ADS)

    Suhaemi, Tjipta; Syaukat, Achmad

    2010-06-01

    THE ACCEPTANCE STRATEGY FOR NUCLEAR POWER PLANT IN INDONESIA. Indonesia has planned to build nuclear power plants. Some feasibility studies have been conducted intensively. However, the processes of NPP introduction are still uncertain. National Energy Plan in Indonesia, which has been made by some governmental agencies, does not yet give positive impact to the government decision to construct the nuclear power plant (NPP). This paper discusses the process of NPP introduction in Indonesia, which has been colored with debate of stakeholder and has delayed decision for go-nuclear. The technology paradigm is used to promote NPP as an alternative of reliable energy resources. This paradigm should be complemented with international politic-economic point of view. The international politic-economic point of view shows that structural powers, consisting of security, production, finance, and knowledge structures, within which the NPP is introduced, have dynamic characteristics. The process of NPP introduction in Indonesia contains some infrastructure development (R&D, legislation, regulation, energy planning, site study, public acceptance efforts, etc), but they need a better coherent NPP implementation program and NPP Acceptance Program. Strategic patterns for NPP acceptance described in this paper are made by considering nuclear regulation development and the interest of basic domestic participation. The first NPP program in Indonesia having proven technology and basic domestic participation is and important milestone toward and optimal national energy-mix.

  9. Unravelling the magmatic processes behind zoned fall units on Ascension Island, South Atlantic

    NASA Astrophysics Data System (ADS)

    Chamberlain, K. J.; Barclay, J.; Preece, K.; Brown, R. J.; Davidson, J.

    2015-12-01

    Ascension Island, an isolated composite volcano in the south Atlantic, has a wide spectrum of explosive and effusive deposits. Eruptions on the island have produced ash and pumice fall deposits, ignimbrites, scoria cones, lava flows and lava domes, which vary in composition from basalt to rhyolite. We report, for the first time, the presence of multiple, zoned pumice fall deposits. These deposits grade upwards (stepwise or gradationally) from pumice to scoria. We present detailed observations of two key deposits which typify the range in zonation observed in the unusual fall units. Forensic examination of these deposits and their petrological and geochemical characteristics provide critical information about the interactions and processes behind the wide spectrum of magma compositions and past eruptive behaviour on Ascension Island. The first deposit changes gradationally from fayalite-bearing trachytic pumice fall (61.1 wt.% SiO2) at the base, to basaltic trachy-andesite scoria fall (54.5 wt.% SiO2) at the top. The second deposit is more complex. It contains mingled pumice-scoria clasts, has a rapid transition from pumice to scoria and no intermediate clasts were observed. New analyses of H2O, CO2 and key trace elements within melt inclusions combined with systematic whole rock and phenocryst analyses enable us to probe the relationship of these co-erupted magmas to other deposits on the island. This has yielded insights into the magma plumbing system; and improved understanding of the roles that fractional crystallisation and magma mixing play in generating the range in compositions observed at this unique ocean island volcano.

  10. Abdicating power for control: a precision timing strategy to modulate function of flight power muscles

    PubMed Central

    Sponberg, S.; Daniel, T. L.

    2012-01-01

    Muscles driving rhythmic locomotion typically show strong dependence of power on the timing or phase of activation. This is particularly true in insects' main flight muscles, canonical examples of muscles thought to have a dedicated power function. However, in the moth (Manduca sexta), these muscles normally activate at a phase where the instantaneous slope of the power–phase curve is steep and well below maximum power. We provide four lines of evidence demonstrating that, contrary to the current paradigm, the moth's nervous system establishes significant control authority in these muscles through precise timing modulation: (i) left–right pairs of flight muscles normally fire precisely, within 0.5–0.6 ms of each other; (ii) during a yawing optomotor response, left—right muscle timing differences shift throughout a wider 8 ms timing window, enabling at least a 50 per cent left–right power differential; (iii) timing differences correlate with turning torque; and (iv) the downstroke power muscles alone causally account for 47 per cent of turning torque. To establish (iv), we altered muscle activation during intact behaviour by stimulating individual muscle potentials to impose left—right timing differences. Because many organisms also have muscles operating with high power–phase gains (Δpower/Δphase), this motor control strategy may be ubiquitous in locomotor systems. PMID:22833272

  11. Ascension Submarine Canyon, California - Evolution of a multi-head canyon system along a strike-slip continental margin

    USGS Publications Warehouse

    Nagel, D.K.; Mullins, H.T.; Greene, H. Gary

    1986-01-01

    Ascension Submarine Canyon, which lies along the strike-slip (transform) dominated continental margin of central California, consists of two discrete northwestern heads and six less well defined southeastern heads. These eight heads coalesce to form a single submarine canyon near the 2700 m isobath. Detailed seismic stratigraphic data correlated with 19 rock dredge hauls from the walls of the canyon system, suggest that at least one of the two northwestern heads was initially eroded during a Pliocene lowstand of sea level ???3.8 m.y. B.P. Paleogeographic reconstructions indicate that at this time, northwestern Ascension Canyon formed the distal channel of nearby Monterey Canyon and has subsequently been offset by right-lateral, strike-slip faulting along the San Gregorio fault zone. Some of the six southwestern heads of Ascension Canyon may also have been initially eroded as the distal portions of Monterey Canyon during late Pliocene-early Pleistocene sea-level lowstands (???2.8 and 1.75 m.y. B.P.) and subsequently truncated and offset to the northwest. There have also been a minimum of two canyon-cutting episodes within the past 750,000 years, after the entire Ascension Canyon system migrated to the northwest past Monterey Canyon. We attribute these late Pleistocene erosional events to relative lowstands of sea level 750,000 and 18,000 yrs B.P. The late Pleistocene and Holocene evolution of the six southeastern heads also appears to have been controlled by structural uplift of the Ascension-Monterey basement high at the southeastern terminus of the Outer Santa Cruz Basin. We believe that uplift of this basement high sufficiently oversteepened submarine slopes to induce gravitational instability and generate mass movements that resulted in the erosion of the canyon heads. Most significantly, though, our results and interpretations support previous proposals that submarine canyons along strike-slip continental margins can originate by tectonic trunction and lateral

  12. Methane at Ascension Island, southern tropical Atlantic Ocean: continuous ground measurement and vertical profiling above the Trade-Wind Inversion

    NASA Astrophysics Data System (ADS)

    Lowry, David; Brownlow, Rebecca; Fisher, Rebecca; Nisbet, Euan; Lanoisellé, Mathias; France, James; Thomas, Rick; Mackenzie, Rob; Richardson, Tom; Greatwood, Colin; Freer, Jim; Cain, Michelle; Warwick, Nicola; Pyle, John

    2015-04-01

    Methane mixing ratios have been rising rapidly worldwide since 2007. At Ascension Island (8oS in the equatorial Atlantic), a sustained rise has occurred. Prior to 2010, growth was comparable to other regions, but in 2010-11, during a strong la Nina event, the increase was 10ppb year-on-year. Reduced growth followed in 2011-12, but in 2012-13 strong growth resumed and continues. This rise has been accompanied by a shift to lighter δ13CCH4 values in 2010-11 in the equatorial tropics. The most likely cause of this shift is emissions from isotopically 'light' biological sources in the equatorial and savanna tropics. Ascension Island is in the Trade Wind belt of the tropical Atlantic, perfectly located to measure the South Atlantic marine boundary layer. The SE Trade Winds are almost invariant, derived from the deep South Atlantic and with little contact with Africa. However, above the Trade Wind Inversion (TWI) at about 1200-2000m asl, the air masses are very different, coming dominantly from tropical Africa and occasionally S. America. Depending on season, air above the TWI is sourced from the African southern savanna grasslands or the equatorial wetlands of Congo and Uganda, with inputs of air also from southern tropical S. America (Brazil, Paraguay, Bolivia). African methane sources are a major contributor to the global methane budget, but although local campaign studies have been made, African emissions are not well studied in bulk. In September 2014, an octocopter was used to retrieve air samples from heights up to 2700m asl on Ascension (see Thomas, R. et al, this volume). This allowed sampling through the marine boundary layer, across the TWI cloud layer, and into the mid-troposphere. Samples were collected in part-filled 5L Tedlar bags, which were analysed for CH4 concentration using Royal Holloway's Picarro 1301 CRDS system at the Met Office, Ascension. This has high precision and accuracy, with a 6-gas calibration suite. Bags were then analysed in the UK for

  13. Covariate Adjustment Strategy Increases Power in the Randomized Controlled Trial With Discrete-Time Survival Endpoints

    ERIC Educational Resources Information Center

    Safarkhani, Maryam; Moerbeek, Mirjam

    2013-01-01

    In a randomized controlled trial, a decision needs to be made about the total number of subjects for adequate statistical power. One way to increase the power of a trial is by including a predictive covariate in the model. In this article, the effects of various covariate adjustment strategies on increasing the power is studied for discrete-time…

  14. Calibration of Hydrophone Stations: Lessons Learned from the Ascension Island Experiment

    SciTech Connect

    Harben, P E; Rodgers, A J

    2000-07-11

    Calibration of hydroacoustic stations for nuclear explosion monitoring is important for increasing monitoring capability and confidence from newly installed stations and from existing stations. Calibration of hydroacoustic stations is herein defined as the near-field precision location of the hydrophones and determination of the amplitude response; and the regional-scale calibration of acoustic traveltimes, bathymetric shadowing, diffraction, and reflection as recorded at a particular station. An important type of calibration not considered here is ocean-basin-scale calibration of a hydroacoustic monitoring system. To understand how to best conduct hydroacoustic station calibrations, an experiment was conducted in May 1999 at Ascension Island in the South Atlantic Ocean. The experiment made use of a British oceanographic research vessel towing an airgun array and collected data over three MILS hydrophones that were in use by the National Data Center and the International Data Center. From the towed airgun data we were able to determine the location for each of the three hydrophones to accuracy better than 100 meters in latitude, longitude, and depth. The agreement with the nominal locations was excellent in depth and to within 1 km in latitude and longitude. The depths determined for the hydrophones and the ocean bottom depths determined from the ship's sonar system force the conclusion that all three hydrophones are located at or near the ocean bottom. Amplitude frequency response of the hydrophones was also calibrated using a calibrated temporarily deployed hydrophone to determine the airgun source function. With the source function known, the amplitude and phase response of the hydrophones could be deconvolved from the recorded waveforms provided a ''pure'' source waveform arrival is identified on the recording. Unfortunately, since the hydrophones are located near the ocean bottom, the recording is contaminated by reflections and scattered energy, making a

  15. Robust neuro-sliding mode multivariable control strategy for powered wheelchairs.

    PubMed

    Nguyen, Tuan Nghia; Su, Steven W; Nguyen, Hung T

    2011-02-01

    This paper proposes an advanced robust multivariable control strategy for a powered wheelchair system. The new control strategy is based on a combination of the systematic triangularization technique and the robust neuro-sliding mode control approach. This strategy effectively copes with parameter uncertainties and external disturbances in real-time in order to achieve robustness and optimal performance of a multivariable system. This novel strategy reduces coupling effects on a multivariable system, eliminates chattering phenomena, and avoids the plant Jacobian calculation problem. Furthermore, the strategy can also achieve fast and global convergence using less computation. The effectiveness of the new multivariable control strategy is verified in real-time implementation on a powered wheelchair system. The obtained results confirm that robustness and desired performance of the overall system are guaranteed, even under parameter uncertainty and external disturbance effects. PMID:20805057

  16. Hydrodynamic theory for reverse brazil nut segregation and the non-monotonic ascension dynamics

    NASA Astrophysics Data System (ADS)

    Alam, Meheboob; Trujillo, L.; Herrmann, H. J.

    2006-08-01

    larger) the intruder, the faster it ascends. The peak on the rise-time curve decreases in height and shifts to a lower density-ratio as we increase the pseudo-thermal buoyancy force. The rise (/sink) time diverges near the threshold density-ratio for reverse-segregation. Our theory offers a unified description for the (reverse) Brazil-nut segregation and the nonmonotonic ascension dynamics of Brazil-nuts.

  17. Description of Alpheus cedrici sp. n., a strikingly coloured snapping shrimp (Crustacea, Decapoda, Alpheidae) from Ascension Island, central Atlantic Ocean

    PubMed Central

    Anker, Arthur; Grave, Sammy De

    2012-01-01

    Abstract Alpheus cedrici sp. n. is described based on two specimens collected under rocks while scuba diving off the coast of Ascension Island, central Atlantic Ocean. The new species belongs to the Alpheus macrocheles (Hailstone, 1835) species complex and appears to be most closely related to the eastern–central Atlantic Alpheus macrocheles, the western Atlantic Alpheus amblyonyx Chace, 1972, and the eastern Pacific Alpheus bellimanus Lockington, 1877 and Alpheus rectus Kim & Abele, 1988. However, it differs from all these species by a combination of morphological characters and by a diagnostic and striking colour pattern. PMID:22573945

  18. Bring Powerful Writing Strategies Into Your Classroom! Why and How

    ERIC Educational Resources Information Center

    Harris, Karen R.; Graham, Steve; Friedlander, Barbara; Laud, Leslie

    2013-01-01

    Learning to write is critical in today's world, yet many students are not developing the writing abilities they need to use writing as a powerful tool for learning and for showing what they know. Research indicates that failure to acquire strong writing abilities restricts opportunities for both post-secondary education and employment. This…

  19. Automation Power Energy Management Strategy for Mobile Telecom Industry

    NASA Astrophysics Data System (ADS)

    Hwang, Jong-Ching; Chen, Jung-Chin; Pan, Jeng-Shyang; Huang, Yi-Chao

    The aim of this research is to study the power energy cost reduction of the mobile telecom industry through the supervisor control and data acquisition (SCADA) system application during globalization and liberalization competition. Yet this management system can be proposed functions: operating monitors, the analysis on load characteristics and dropping the cost of management.

  20. Optimization strategy for element sizing in hybrid power systems

    NASA Astrophysics Data System (ADS)

    del Real, Alejandro J.; Arce, Alicia; Bordons, Carlos

    This paper presents a procedure to evaluate the optimal element sizing of hybrid power systems. In order to generalize the problem, this work exploits the "energy hub" formulation previously presented in the literature, defining an energy hub as an interface among energy producers, consumers and the transportation infrastructure. The resulting optimization minimizes an objective function which is based on costs and efficiencies of the system elements, while taking into account the hub model, energy and power constraints and estimated operational conditions, such as energy prices, input power flow availability and output energy demand. The resulting optimal architecture also constitutes a framework for further real-time control designs. Moreover, an example of a hybrid storage system is considered. In particular, the architecture of a hybrid plant incorporating a wind generator, batteries and intermediate hydrogen storage is optimized, based on real wind data and averaged residential demands, also taking into account possible estimation errors. The hydrogen system integrates an electrolyzer, a fuel cell stack and hydrogen tanks. The resulting optimal cost of such hybrid power plant is compared with the equivalent hydrogen-only and battery-only systems, showing improvements in investment costs of almost 30% in the worst case.

  1. The ELSAM strategy of firing biomass in CFB power plants

    SciTech Connect

    Rasmussen, I.; Clausen, J.C.

    1995-12-31

    The Danish power pool ELSAM has launched a program for developing a coal and biomass-fired CFB concept for future power plants, as an option to achieve a substantial reduction of CO{sub 2} emissions associated with energy generation. The general development of CFB technology abroad and domestic experience gained from small-scale coal and straw firing form the basis for this program. Since January 1992 MIDTKRAFT Power Company has been operating an 80 MWth CFB cogeneration plant located at Grenaa. This plant is fired with a mixture of hard coal and surplus straw from farming. The share of straw ranges from 0-60% on an energy basis. Straw contains much larger amounts of chlorine and potassium than normal fossil fuels, which implies a higher potential of superheater corrosion and combustor fouling. This paper reviews the experience gained during the first 3 years of operation of the CFB plant. The record includes early superheater corrosion and fouling incidents, a heat surface modification and its impact on subsequent plant operation. Apart from operational experience the paper will review the results of the R and D activities executed at the Grenaa plant for further CFB development. Based on the specific experience from Grenaa and the general evolution of the CFB technology ELSAM has initiated a program for development of a 250 MWe CFB power plant concept, firing up to 60% biomass (wood waste and a limited amount of annular crops). USC steam conditions are adopted for the novel concept, implying an expected plant efficiency of 45% (LHV-based). Special emphasis is attached to plant operational flexibility with a view to fulfilling general power plant requirements.

  2. Feedback power control strategies in wireless sensor networks with joint channel decoding.

    PubMed

    Abrardo, Andrea; Ferrari, Gianluigi; Martalò, Marco; Perna, Fabio

    2009-01-01

    In this paper, we derive feedback power control strategies for block-faded multiple access schemes with correlated sources and joint channel decoding (JCD). In particular, upon the derivation of the feasible signal-to-noise ratio (SNR) region for the considered multiple access schemes, i.e., the multidimensional SNR region where error-free communications are, in principle, possible, two feedback power control strategies are proposed: (i) a classical feedback power control strategy, which aims at equalizing all link SNRs at the access point (AP), and (ii) an innovative optimized feedback power control strategy, which tries to make the network operational point fall in the feasible SNR region at the lowest overall transmit energy consumption. These strategies will be referred to as "balanced SNR" and "unbalanced SNR," respectively. While they require, in principle, an unlimited power control range at the sources, we also propose practical versions with a limited power control range. We preliminary consider a scenario with orthogonal links and ideal feedback. Then, we analyze the robustness of the proposed power control strategies to possible non-idealities, in terms of residual multiple access interference and noisy feedback channels. Finally, we successfully apply the proposed feedback power control strategies to a limiting case of the class of considered multiple access schemes, namely a central estimating officer (CEO) scenario, where the sensors observe noisy versions of a common binary information sequence and the AP's goal is to estimate this sequence by properly fusing the soft-output information output by the JCD algorithm. PMID:22291536

  3. A flexible active and reactive power control strategy for a variable speed constant frequency generating system

    SciTech Connect

    Tang, Y.; Xu, L.

    1995-07-01

    Variable-speed constant-frequency generating systems are used in wind power, hydro power, aerospace, and naval power generations to enhance efficiency and reduce friction. In these applications, an attractive candidate is the slip power recovery system comprising of doubly excited induction machine or doubly excited brushless reluctance machine and PWM converters with a dc link. In this paper, a flexible active and reactive power control strategy is developed, such that the optimal torque-speed profile of the turbine can be followed and overall reactive power can be controlled, while the machine copper losses have been minimized. At the same time, harmonics injected into the power network has also been minimized. In this manner, the system can function as both a high-efficient power generator and a flexible reactive power compensator.

  4. The Influence of Gender on the Likelihood of Using Soft Social Power Strategies in School Consultation

    ERIC Educational Resources Information Center

    Getty, Kimberly C.; Erchul, William P.

    2009-01-01

    The social power typology developed originally by French and Raven in 1959 and revised by Raven in 1965 and 1992 was applied to study school consultation. Specifically, we investigated how the gender of school psychologist consultants and teacher consultees influence how likely consultants are to use soft power strategies, identified as those…

  5. Strategies for emission reduction from thermal power plants.

    PubMed

    Prisyazhniuk, Vitaly A

    2006-07-01

    Major polluters of man's environment are thermal power stations (TPS) and power plants, which discharge into the atmosphere the basic product of carbon fuel combustion, CO2, which results in a build-up of the greenhouse effect and global warm-up of our planet's climate. This paper is intended to show that the way to attain environmental safety of the TPS and to abide by the decisions of the Kyoto Protocol lies in raising the efficiency of the heat power stations and reducing their fuel consumption by using nonconventional thermal cycles. Certain equations have been derived to define the quantitative interrelationship between the growth of efficiency of the TPS, decrease in fuel consumption and reduction of discharge of dust, fuel combustion gases, and heat into the environment. New ideas and new technological approaches that result in raising the efficiency of the TPS are briefly covered: magneto-hydrodynamic resonance, the Kalina cycle, and utilizing the ambient heat by using, as the working medium, low-boiling substances. PMID:16338058

  6. Power-aware provisioning strategy with shared path protection in optical WDM networks

    NASA Astrophysics Data System (ADS)

    Bao, Ning-Hai; Li, Le-Min; Yu, Hong-Fang; Zhang, Zhi-Zhong; Luo, Hong-Bin

    2012-03-01

    As the Internet continues to grow, the power consumption of telecommunication networks is rising at a considerable speed, which seriously increases the operational expenditure and greenhouse gas emission. Since optical Wavelength Division Multiplexing (WDM) networks are currently the most promising network infrastructures, power saving issue on these networks has received more attention in recent years. In traditional optical WDM networks, a large amount of power is drained by the redundant idle resources and reserved backup resources although these powered on resources do not carry traffic in most of the time. In order to reduce the network power consumption, turning off the corresponding network components or switching them to a low-power, standby state (or called sleep mode) is a promising greening approach. In this paper, we study the power-aware provisioning strategies and propose a sleep mode based Power-Aware Shared Path Protection (PASPP) heuristic algorithm to achieve the power efficiency of optical WDM networks. By jointly utilizing link-cost and fiber-cost in path routing, resource assignment, and resource release, PASPP makes working paths and backup paths converge on different fibers as much as possible, and switch idle and backup components to sleep mode to realize power saving. Simulation results show that our PASPP can obtain notable power saving and achieve satisfactory tradeoff between power efficiency and blocking probability with respect to Power-Unaware Shared Path Protection (PUSPP).

  7. Power sharing. A transformational strategy for nurse retention, effectiveness, and extra effort.

    PubMed

    Trofino, Joan

    2003-01-01

    Power sharing with staff nurses is an essential strategy for organizational transformation. The current competitive health care environment requires a powerful team of participants, including staff at all levels, to provide health care in mutual partnership. The challenges of today's competitive and global environment call for collegial relationships among nurse executive leadership, middle nurse managers, and staff nurses. Research has demonstrated that middle nurse managers maintain primary responsibility for staff nurse retention. A higher retention rate was reported among nurses who were very satisfied with their nurse managers. Nurses considered favorably nurse managers who value staff contributions, promote information sharing, and exert influence for a stable work environment. Furthermore, as staff nurse satisfaction increased, effectiveness and extra effort also increased when staff nurses perceived transformational leadership strategies. Strategies for power sharing include serving as role models and mentors, energizing staff, resisting attitudes of staff ownership, reducing staff nurse stress of leader presence, and information sharing and commendations at meetings. PMID:14997687

  8. Design of a nonlinear backstepping control strategy of grid interconnected wind power system based PMSG

    NASA Astrophysics Data System (ADS)

    Errami, Y.; Obbadi, A.; Sahnoun, S.; Benhmida, M.; Ouassaid, M.; Maaroufi, M.

    2016-07-01

    This paper presents nonlinear backstepping control for Wind Power Generation System (WPGS) based Permanent Magnet Synchronous Generator (PMSG) and connected to utility grid. The block diagram of the WPGS with PMSG and the grid side back-to-back converter is established with the dq frame of axes. This control scheme emphasises the regulation of the dc-link voltage and the control of the power factor at changing wind speed. Besides, in the proposed control strategy of WPGS, Maximum Power Point Tracking (MPPT) technique and pitch control are provided. The stability of the regulators is assured by employing Lyapunov analysis. The proposed control strategy for the system has been validated by MATLAB simulations under varying wind velocity and the grid fault condition. In addition, a comparison of simulation results based on the proposed Backstepping strategy and conventional Vector Control is provided.

  9. Analysis of a Static Start-up Control Strategy for Pumped Storage Power Plant Unit

    NASA Astrophysics Data System (ADS)

    Wang, Deshun; Yang, Bo; Li, Guanjun; Tao, Yibin; Sang, Bingyu

    A static start-up control strategy for pumped storage power plant unit is presented and the sensor less control to rotor position detecting is analyzed according to voltage and magnetism equations of ideal synchronous motor mathematics model. The simple-to-implement estimation technique of sensor less control to rotor position detecting in which operates over a wide speed range, including zero speed, is presented also. Control strategy of static start-up and its mathematical model is discussed in detail. Based on 500 kW synchronous motor, the test of static start- up control system for pumped storage power plant unit is developed. Test results show that pulse commutation, nature commutation and unit synchronous procedure of static start-up are realized. Then it is proved that the method presented in the paper is a practicable control strategy for static start-up control to pumped storage power plant.

  10. Modeling the conversion of hydroacoustic to seismic energy at island and continental margins: preliminary analysis of Ascension Island data

    SciTech Connect

    Harben, P.; Rodgers, A.

    1999-07-26

    -phase amplitudes. For this paper we will focus on validating the finite difference method for modeling T-phases in the ocean and land environments and on modeling T-phases observed by the May 1999 Ascension Island Experiment. A network of broadband seismometers on Ascension Island recorded a large number of offshore airgun shots. The shots occurred at all azimuths around the island and at ranges from 1-45 km. Measurements of signal amplitude and duration will be made to understand the variability of T-phase behavior on Ascension Island. The sensitivity to topographic slope and island structure will also be investigated.

  11. Powering the Digital Economy Workshop Proceedings: Part 1: Strategies and Planning

    SciTech Connect

    2001-02-01

    Developing ''Internet-compatible'' facilities is critical to the future success of the electric power industry. To optimize their use of the Internet, utilities and their customers need to identify and define relevant issues and problems, focus on economic incentives and solutions, and initiate targeted strategies while planning for future business initiatives. To help meet these needs, EPRI established a workshop series, ''Powering the Digital Economy.''

  12. Control strategies to optimise power output in heave buoy energy convertors

    NASA Astrophysics Data System (ADS)

    Abu Zarim, M. A. U. A.; Sharip, R. M.

    2013-12-01

    Wave energy converter (WEC) designs are always discussed in order to obtain an optimum design to generate the power from the wave. Output power from wave energy converter can be improved by controlling the oscillation in order to acquire the interaction between the WEC and the incident wave.The purpose of this research is to study the heave buoys in the interest to generate an optimum power output by optimising the phase control and amplitude in order to maximise the active power. In line with the real aims of this study which investigate the theory and function and hence optimise the power generation of heave buoys as renewable energy sources, the condition that influence the heave buoy must be understand in which to propose the control strategies that can be use to control parameters to obtain optimum power output. However, this research is in an early stage, and further analysis and technical development is require.

  13. Health assessment for Old Inger, Ascension Parish, Darrow, Louisiana, Region 6. CERCLIS No. LAD980745533. Final report

    SciTech Connect

    Not Available

    1988-10-20

    The Old Inger National Priorities List site is located adjacent to the Mississippi River in Ascension Parish, about 4.5 miles north of Darrow, Louisiana. Surface soils at the site are contaminated with petroleum refinery wastes, spent catalysts, and spent solvents. The site is classified as wetlands and contains a swamp that has also been contaminated with petroleum-refinery wastes. On-site ground waters are contaminated with volatile organic compounds (VOCs) and polynuclear aromatic hydrocarbons that have leached into shallow and intermediate aquifers. Remediation includes provisions that on-site waste oils and heavily contaminated surface waters and the shallow aquifer be treated, that surface structures be torn down and decontaminated, that ungrouted annual space be sealed around an abandoned on-site water well, and that all contaminated soils be placed in a landfill and the landfill capped.

  14. Assessment of United States and Japanese Athletic Trainers' Satisfaction with Current Ascension Pathways and Interest in Future Transnational Certification

    ERIC Educational Resources Information Center

    Presuto, Dax A.

    2013-01-01

    Background: The purpose of this cross-system and cross-cultural study was to investigate the current athletic training systems in the US and Japan, to assess US and Japanese athletic trainers' satisfaction with current athletic training ascension pathways in their respective country and to determine their interest in future transnational…

  15. Ascension Patterns and Experiences of Past and Present Female Trustee Board Chairpersons at Independent Colleges and Universities in a Southern State

    ERIC Educational Resources Information Center

    Ricks Scott, Heather Inez

    2010-01-01

    The purpose of this study was to examine the ascension patterns and experiences of past and present female board of trustee chairpersons at independent institutions in a southeastern state. Although females continue to account for more of the college student population and obtain more degrees than males, females are severely underrepresented in…

  16. Simulation and comparison of different operational strategies for storage utilization in concentrated solar power plants

    NASA Astrophysics Data System (ADS)

    García-Barberena, Javier; Erdocia, Ioseba

    2016-05-01

    The increase of electric power demand and the wish to protect the environment are leading to a change in the energy sources. Conventional energy plants are losing strength against the renewable energy plants and, in particular, solar energy plants have a huge potential to provide clean energy supply for the increasing world's energy demand. Among the existing solar technologies, Concentrating Solar Power (CSP) is one of the most promising technologies. One of the major advantages of CSP plants is the technically feasible and cost-effective integration of Thermal Energy Storage (TES) systems. To increase the plant dispatchability, it is possible to create different operational strategies defining how such TES system is used. In this work, different strategies with different overall goals have been simulated over a complete year and the results are presented and compared here to demonstrate the capabilities of the operational strategies towards an increased dispatchability and plant economic effectiveness. The analysis shows that different strategies may lead to significant differences in the plant annual production, expected economic incomes, number of power block stops, mean efficiency, etc. Specifically, it has been found that the economic incomes of a plant can be increased (+1.3%) even with a decreased total energy production (-1.5%) if the production is scheduled to follow a demand/price curve. Also, dramatic reduction in the number of turbine stops (-67%) can be achieved if the plant is operated towards this objective. The strategies presented in this study have not been optimized towards any specific objective, but only created to show the potential of well designed operational strategies in CSP plants. Therefore, many other strategies as well as optimized versions of the strategies explained below are possible and will be analyzed in future works.

  17. Ultrahigh-Power-Factor Carbon Nanotubes and an Ingenious Strategy for Thermoelectric Performance Evaluation.

    PubMed

    Zhou, Wenbin; Fan, Qingxia; Zhang, Qiang; Li, Kewei; Cai, Le; Gu, Xiaogang; Yang, Feng; Zhang, Nan; Xiao, Zhuojian; Chen, Huiliang; Xiao, Shiqi; Wang, Yanchun; Liu, Huaping; Zhou, Weiya; Xie, Sishen

    2016-07-01

    An ingenious strategy is put forward to evaluate accurately the thermoelectric performance of carbon nanotube (CNT) thin films, including thermal conductivity, electrical conductivity, and Seebeck coefficient in the same direction. The results reveal that the as-prepared CNT interconnected films and CNT fibers possess enormous potential of thermoelectric applications because of their ultrahigh power factors. PMID:27199099

  18. Predictive-model-based dynamic coordination control strategy for power-split hybrid electric bus

    NASA Astrophysics Data System (ADS)

    Zeng, Xiaohua; Yang, Nannan; Wang, Junnian; Song, Dafeng; Zhang, Nong; Shang, Mingli; Liu, Jianxin

    2015-08-01

    Parameter-matching methods and optimal control strategies of the top-selling hybrid electric vehicle (HEV), namely, power-split HEV, are widely studied. In particular, extant research on control strategy focuses on the steady-state energy management strategy to obtain better fuel economy. However, given that multi-power sources are highly coupled in power-split HEVs and influence one another during mode shifting, conducting research on dynamic coordination control strategy (DCCS) to achieve riding comfort is also important. This paper proposes a predictive-model-based DCCS. First, the dynamic model of the objective power-split HEV is built and the mode shifting process is analyzed based on the developed model to determine the reason for the system shock generated. Engine torque estimation algorithm is then designed according to the principle of the nonlinear observer, and the prediction model of the degree of shock is established based on the theory of model predictive control. Finally, the DCCS with adaptation for a complex driving cycle is realized by combining the feedback control and the predictive model. The presented DCCS is validated on the co-simulation platform of AMESim and Simulink. Results show that the shock during mode shifting is well controlled, thereby improving riding comfort.

  19. Carbon Emissions Trading and Combined Heat and Power Strategies: Unintended Consequences

    ERIC Educational Resources Information Center

    Tysseling, John C.; Vosevich, Mary; Boersma, Benjamin R.; Zumwalt, Jefferey A.

    2009-01-01

    Facility professionals continuously search for projects that reduce energy consumption and operating costs so as to directly benefit their bottom line. Many institutions nationwide have contemplated or made investments in combined heat and power (CHP) projects as a life-cycle strategy to minimize operating costs. However, recent sustainability and…

  20. Authority Base, Denomination, Moral Philosophy and the Power Strategies Used by Clergymen.

    ERIC Educational Resources Information Center

    Falbo, Toni; And Others

    Clergymen are regarded by their congregations as having the authority to influence church members and clergymen are expected to exert influence. Three types of clerical authority have been identified: charismatic, traditional, and legal-rational. The common assumption that people select power strategies that are consistent with their perceptions…

  1. Analysis of Strategies for Reducing Multiple Emissions from Electric Power Plants: SO2, Nox, CO2

    EIA Publications

    2001-01-01

    This report responds to a request received from Senator David McIntosh on June 29, 2000 to analyze the impacts on energy consumers and producers of coordinated strategies to reduce emissions of sulfur dioxide, nitrogen oxides, and carbon dioxide at U.S. power plants.

  2. Strategies for development and CO2 abatement in China`s power industry

    SciTech Connect

    Ying, R.

    1996-12-31

    Chinese Government has set a series sustainable energy development policies and strategies to alleviate atmospheric pollution and to mitigate the CO2 emission. Some major policies and measures that will be emphasized in China`s power industrial development will be addressed in this paper.

  3. Investigation of Containment Flooding Strategy for Mark-III Nuclear Power Plant with MAAP4

    SciTech Connect

    Su Weinian; Wang, S.-J.; Chiang, S.-C

    2005-06-15

    Containment flooding is an important strategy for severe accident management of a conventional boiling water reactor (BWR) system. The purpose of this work is to investigate the containment flooding strategy of the Mark-III system after a reactor pressure vessel (RPV) breach. The Kuosheng Power Plant is a typical BWR-6 nuclear power plant (NPP) with Mark-III containment. The Severe Accident Management Guideline (SAMG) of the Kuosheng NPP has been developed based on the BWR Owners Group (BWROG) Emergency Procedure and Severe Accident Guidelines, Rev. 2. Therefore, the Kuosheng NPP is selected as the plant for study, and the MAAP4 code is chosen as the tool for analysis. A postulated specific station blackout sequence for the Kuosheng NPP is cited as a reference case for this analysis. Because of the design features of Mark-III containment, the debris in the reactor cavity may not be submerged after an RPV breach when one follows the containment flooding strategy as suggested in the BWROG generic guideline, and the containment integrity could be challenged eventually. A more specific containment flooding strategy with drywell venting after an RPV breach is investigated, and a more stable plant condition is achieved with this strategy. Accordingly, the containment flooding strategy after an RPV breach will be modified for the Kuosheng SAMG, and these results are applicable to typical Mark-III plants with drywell vent path.

  4. The alternative strategies of the development of the nuclear power industry in the 21st century

    NASA Astrophysics Data System (ADS)

    Goverdovskii, A. A.; Kalyakin, S. G.; Rachkov, V. I.

    2014-05-01

    This paper emphasizes the urgency of scientific-and-technical and sociopolitical problems of the modern nuclear power industry without solving of which the transition from local nuclear power systems now in operation to a large-scale nuclear power industry would be impossible. The existing concepts of the longterm strategy of the development of the nuclear power industry have been analyzed. On the basis of the scenarios having been developed it was shown that the most promising alternative is the orientation towards the closed nuclear fuel cycle with fast neutron reactors (hereinafter referred to as fast reactors) that would meet the requirements on the acceptable safety. It was concluded that the main provisions of "The Strategy of the Development of the Nuclear Power Industry of Russia for the First Half of the 21st Century" approved by the Government of the Russian Federation in the year 2000 remain the same at present as well, although they require to be elaborated with due regard for new realities in the market for fossil fuels, the state of both the Russian and the world economy, as well as tightening of requirements related to safe operation of nuclear power stations (NPSs) (for example, after the severe accident at the Fukushima nuclear power station, Japan) and nonproliferation of nuclear weapons.

  5. Voltage Sag Mitigation Strategies for an Indian Power Systems: A Case Study

    NASA Astrophysics Data System (ADS)

    Goswami, A. K.; Gupta, C. P.; Singh, G. K.

    2014-08-01

    Under modern deregulated environment, both utilities and customers are concerned with the power quality improvement but with different objectives/interests. The utility reconfigure its power network and install mitigation devices, if needed, to improve power quality. The paper presents a strategy for selecting cost-effective solutions to mitigate voltage sags, the most frequent power quality disturbance. In this paper, mitigation device(s) is/are inducted in the optimal network topology at suitable places for their better effectiveness for further improvement in power quality. The optimal placement is looked from utility perspectives for overall benefit. Finally, their performance is evaluated on the basis of reduction in total number of voltage sags, reduction in total number of process trips and reduction in total financial losses due to voltage sags.

  6. Nucléation, ascension et éclatement d'une bulle de champagne

    NASA Astrophysics Data System (ADS)

    Liger-Belair, G.

    2006-03-01

    trains de bulles ainsi qu'à la détermination de la vitesse ascensionnelle des bulles. Les mesures expérimentales du rayon et de la vitesse d'une bulle nous ont permis de déterminer le coefficient de traînée d'une bulle montante qui constitue une mesure indirecte de son état de surface en termes de mobilité interfaciale. Ces mesures nous ont montré que l'interface d'une bulle de champagne conserve une grande mobilité interfaciale pendant sa phase ascensionnelle, à la différence des bulles de taille fixe qui montent dans une solution de macromolécules tensioactives. C'est la faible dilution du champagne en macromolécules tensioactives et le grossissement continu des bulles pendant l'ascension qui assurent aux bulles une faible contamination de leur interface. Pour comparaison, nous avons réalisé le même type de mesures sur des bulles de bière. Le contenu en macromolécules tensioactives étant beaucoup plus important dans une bière, l'effet de dilution du matériel tensioactif à la surface des bulles lié à l'accroissement de la surface des bulles ne compense plus l'adsorption massive des tensioactifs à la surface des bulles. Contrairement aux bulles du champagne, les bulles de bière adoptent vite un comportement de type sphère rigide. Nous avons également discuté l'influence relative de certains paramètres sur la taille des bulles lorsqu'elles parviennent en surface. Il a notamment été montré que le rôle théorique joué par la température du champagne sur la taille des bulles est quasiment négligeable. Pour finir, nous avons proposé d'essayer de faire du train de bulles une sorte d'empreinte digitale du liquide effervescent dans lequel il évolue en analysant la dynamique ascensionnelle des bulles via la mesure de leur coefficient de frottement. Nous avons pu différencier à ce jour par cette méthode trois grandes familles de boissons gazeuses : les vins effervescents au sens large (champagne compris), les bières et les eaux gazeuses

  7. Dynamic modeling and evaluation of solid oxide fuel cell - combined heat and power system operating strategies

    NASA Astrophysics Data System (ADS)

    Nanaeda, Kimihiro; Mueller, Fabian; Brouwer, Jacob; Samuelsen, Scott

    Operating strategies of solid oxide fuel cell (SOFC) combined heat and power (CHP) systems are developed and evaluated from a utility, and end-user perspective using a fully integrated SOFC-CHP system dynamic model that resolves the physical states, thermal integration and overall efficiency of the system. The model can be modified for any SOFC-CHP system, but the present analysis is applied to a hotel in southern California based on measured electric and heating loads. Analysis indicates that combined heat and power systems can be operated to benefit both the end-users and the utility, providing more efficient electric generation as well as grid ancillary services, namely dispatchable urban power. Design and operating strategies considered in the paper include optimal sizing of the fuel cell, thermal energy storage to dispatch heat, and operating the fuel cell to provide flexible grid power. Analysis results indicate that with a 13.1% average increase in price-of-electricity (POE), the system can provide the grid with a 50% operating range of dispatchable urban power at an overall thermal efficiency of 80%. This grid-support operating mode increases the operational flexibility of the SOFC-CHP system, which may make the technology an important utility asset for accommodating the increased penetration of intermittent renewable power.

  8. Adjacency Matrix-Based Transmit Power Allocation Strategies in Wireless Sensor Networks

    PubMed Central

    Consolini, Luca; Medagliani, Paolo; Ferrari, Gianluigi

    2009-01-01

    In this paper, we present an innovative transmit power control scheme, based on optimization theory, for wireless sensor networks (WSNs) which use carrier sense multiple access (CSMA) with collision avoidance (CA) as medium access control (MAC) protocol. In particular, we focus on schemes where several remote nodes send data directly to a common access point (AP). Under the assumption of finite overall network transmit power and low traffic load, we derive the optimal transmit power allocation strategy that minimizes the packet error rate (PER) at the AP. This approach is based on modeling the CSMA/CA MAC protocol through a finite state machine and takes into account the network adjacency matrix, depending on the transmit power distribution and determining the network connectivity. It will be then shown that the transmit power allocation problem reduces to a convex constrained minimization problem. Our results show that, under the assumption of low traffic load, the power allocation strategy, which guarantees minimal delay, requires the maximization of network connectivity, which can be equivalently interpreted as the maximization of the number of non-zero entries of the adjacency matrix. The obtained theoretical results are confirmed by simulations for unslotted Zigbee WSNs. PMID:22346705

  9. An Exploration of Upper-Intermediate Iranian EFL Learners' Perception of Politeness Strategies and Power Relation in Disagreement

    ERIC Educational Resources Information Center

    Niroomand, Masoumeh

    2012-01-01

    The present study was designed to examine the ways power relations influence politeness strategies in disagreement. The study was an attempt to find out whether different power status of people influences the the choice of appropriate politeness strategies and speech act of disagreement by Iranian EFL learners, in a university setting. A Discourse…

  10. Using a Multicomponent Adapted Power Card Strategy to Decrease Latency during Interactivity Transitions for Three Children with Developmental Disabilities

    ERIC Educational Resources Information Center

    Angell, Maureen E.; Nicholson, Joanna K.; Watts, Emily H.; Blum, Craig

    2011-01-01

    An adapted Power Card strategy was examined to determine effectiveness in decreasing latency in responding to teacher cues to initiate interactivity transitions in the classroom among three students, aged 10 to 11 years, with developmental disabilities (i.e., one with autism and two with intellectual disability). The Power Card strategy, a form of…

  11. The Power Card Strategy: Strength-Based Intervention to Increase Direction Following of Children with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Campbell, Abbi; Tincani, Matt

    2011-01-01

    The Power Card strategy is a strength-based intervention to promote social skills of children with autism spectrum disorders (ASD) by capitalizing on their special interests. Although preliminary studies have shown that the Power Card strategy is a promising approach to teach social skills, additional research is needed. The purpose of this study…

  12. Utility-Marketing Partnerships: An Effective Strategy for Marketing Green Power?

    SciTech Connect

    Bird, L. A.; Brown, E. S.

    2006-04-01

    This paper explores whether partnerships between utilities and independent marketers are an effective strategy for marketing green power. We present case studies of voluntary and mandatory partnerships covering green power program design and implementation in both regulated and restructured electricity markets. We also include perspectives (based on interviews) from utilities, marketers, and regulators involved in developing and implementing these partnerships. From these case studies and interviews, we describe lessons learned about developing effective partnerships, including such issues as respective roles in marketing and administration, product branding, and contract and incentive structures. Based on experience to date, strategic partnerships between utilities and marketers can be an effective approach to marketing green power. Partnerships leverage the sales and resource procurement experience of marketers and the utility?s reputation and access to customers. Further, partnerships can create greater incentives for success because marketers have a vested financial interest in maximizing customer participation and green power sales.

  13. Utility-Marketer Partnerships. An Effective Strategy for Marketing Green Power?

    SciTech Connect

    Bird, L. A.; Brown, E. S.

    2006-04-01

    This paper explores whether partnerships between utilities and independent marketers are an effective strategy for marketing green power. We present case studies of voluntary and mandatory partnerships covering green power program design and implementation in both regulated and restructured electricity markets. We also include perspectives (based on interviews) from utilities, marketers, and regulators involved in developing and implementing these partnerships. From these case studies and interviews, we describe lessons learned about developing effective partnerships, including such issues as respective roles in marketing and administration, product branding, and contract and incentive structures. Based on experience to date, strategic partnerships between utilities and marketers can be an effective approach to marketing green power. Partnerships leverage the sales and resource procurement experience of marketers and the utility’s reputation and access to customers. Further, partnerships can create greater incentives for success because marketers have a vested financial interest in maximizing customer participation and green power sales.

  14. [Strategies of power and leadership for the development of nurses' social compromise].

    PubMed

    Alberdi Castell, R

    1998-01-01

    This article presents an analysis about power and leadership regarding the nursing profession in Spain and poses some strategies which, from the aforementioned perspective, allow the compromise nurses have with society to develop. This article has three sections: one which defines terms such as power, leadership, representative, corporation, ...; a second section which analyzes and makes proposals, wherein the current situation of the nursing profession is described in relation with the elements defined as the shapers of professional power, and proposals are posed along the lines of one to demand clear guidelines for nurses' professional role, to act in a "corporational" way, in positive terms, or to recognize the importance "informal" power networks hold; and finally, a section of conclusions. PMID:9739285

  15. 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.

  16. Cyber attacks against state estimation in power systems: Vulnerability analysis and protection strategies

    NASA Astrophysics Data System (ADS)

    Liu, Xuan

    Power grid is one of the most critical infrastructures in a nation and could suffer a variety of cyber attacks. With the development of Smart Grid, false data injection attack has recently attracted wide research interest. This thesis proposes a false data attack model with incomplete network information and develops optimal attack strategies for attacking load measurements and the real-time topology of a power grid. The impacts of false data on the economic and reliable operations of power systems are quantitatively analyzed in this thesis. To mitigate the risk of cyber attacks, a distributed protection strategies are also developed. It has been shown that an attacker can design false data to avoid being detected by the control center if the network information of a power grid is known to the attacker. In practice, however, it is very hard or even impossible for an attacker to obtain all network information of a power grid. In this thesis, we propose a local load redistribution attacking model based on incomplete network information and show that an attacker only needs to obtain the network information of the local attacking region to inject false data into smart meters in the local region without being detected by the state estimator. A heuristic algorithm is developed to determine a feasible attacking region by obtaining reduced network information. This thesis investigates the impacts of false data on the operations of power systems. It has been shown that false data can be designed by an attacker to: 1) mask the real-time topology of a power grid; 2) overload a transmission line; 3) disturb the line outage detection based on PMU data. To mitigate the risk of cyber attacks, this thesis proposes a new protection strategy, which intends to mitigate the damage effects of false data injection attacks by protecting a small set of critical measurements. To further reduce the computation complexity, a mixed integer linear programming approach is also proposed to

  17. Adaptive supervisory control strategy of a fuel cell/battery-powered city bus

    NASA Astrophysics Data System (ADS)

    Xu, Liangfei; Li, Jianqiu; Hua, Jianfeng; Li, Xiangjun; Ouyang, Minggao

    This paper presents an adaptive supervisory control strategy for a fuel cell/battery-powered city bus to fulfill the complex road conditions in Beijing bus routes. An equivalent consumption minimization strategy (ECMS) is firstly proposed to optimize the fuel economy. The adaptive supervisory control strategy is exploited based on this, incorporating an estimating algorithm for the vehicle accessorial power, an algorithm for the battery charge-sustaining and a Recursive Least Squares (RLS) algorithm for fuel cell performance identification. Finally, an adaptive supervisory controller (ASC) considering the fuel consumption minimization, the battery charge-sustaining and the fuel cell durability has been implemented within the hybrid city buses. Results in the "China city bus typical cycle" testing and the demonstrational program of Beijing bus routes are presented, demonstrating that this approach provides an improvement of fuel economy along with robustness and ease of implementation. However, the fuel cell system does not leave much room for the optimal strategy to promote the fuel economy. Benefits may also result in a prolongation of the fuel cell working life, which needs to be verified in future.

  18. A general solution strategy of modified power method for higher mode solutions

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Lee, Hyunsuk; Lee, Deokjung

    2016-01-01

    A general solution strategy of the modified power iteration method for calculating higher eigenmodes has been developed and applied in continuous energy Monte Carlo simulation. The new approach adopts four features: 1) the eigen decomposition of transfer matrix, 2) weight cancellation for higher modes, 3) population control with higher mode weights, and 4) stabilization technique of statistical fluctuations using multi-cycle accumulations. The numerical tests of neutron transport eigenvalue problems successfully demonstrate that the new strategy can significantly accelerate the fission source convergence with stable convergence behavior while obtaining multiple higher eigenmodes at the same time. The advantages of the new strategy can be summarized as 1) the replacement of the cumbersome solution step of high order polynomial equations required by Booth's original method with the simple matrix eigen decomposition, 2) faster fission source convergence in inactive cycles, 3) more stable behaviors in both inactive and active cycles, and 4) smaller variances in active cycles. Advantages 3 and 4 can be attributed to the lower sensitivity of the new strategy to statistical fluctuations due to the multi-cycle accumulations. The application of the modified power method to continuous energy Monte Carlo simulation and the higher eigenmodes up to 4th order are reported for the first time in this paper.

  19. The geochemical signature of fluid-saturated magma determined from silicate melt inclusions in ascension island granite xenoliths

    NASA Astrophysics Data System (ADS)

    Webster, J. D.; Rebbert, C. R.

    2001-01-01

    Silicate glasses in crystal-free to crystal-poor melt inclusions from two coarse-grained granite xenoliths in alkaline volcanic rocks of Ascension Island were analyzed for 29 major, minor, and trace elements. For most constituents, the glass compositions are similar to those of the volcanic whole rocks and the xenoliths; we interpret the glasses to be chemically representative of granite melt. The melt inclusions are silicic; alkaline; contain low S and P abundances; and are enriched in H 2O, Cl, F, and Na relative to K. Inclusions from one xenolith contain 1.3 wt.% F, on average, whereas those from the other xenolith contain half that amount. The melt inclusion compositions allow investigation of the means and extent of granite magma evolution. The presence of magmatic fluid inclusions in close proximity to melt inclusions in the phenocrysts indicates that the granite melt was saturated in one or more volatile phases (Roedder and Coombs, 1967). The Cl and H 2O contents of the melt inclusions are consistent with the exsolution of volatile phase(s) at pressures of 3000 to 2000 bars. The glasses also show trends involving the (Cl/H 2O) ratio and the incompatible trace elements in melt that are indicative of melt evolution via crystal fractionation of volatile phase-saturated melt. These trends should be useful for recognizing volatile phase saturation in other Cl-enriched melts.

  20. Ascending in healthcare. Roman Catholic Ascension Health has made a Fortune 500 name for itself with business acumen, risk-taking and efficiency.

    PubMed

    Evans, Melanie

    2007-05-14

    In less than a decade, Ascension Health has risen to the top tier of U.S. healthcare systems, with operating revenue that bests household names like Google and Amazon.com. Helping lead the system's meteoric rise is CEO Anthony Tersigni, left. "We are a ministry. We're not a business. We do business practices for one basic reason: We have bondholders who are counting on us to repay the bonds." PMID:17542301

  1. Combined heat and power in the draft of the new Russian energy strategy

    NASA Astrophysics Data System (ADS)

    Makarova, A. S.; Pankrushina, T. G.; Urvantseva, L. V.; Khorshev, A. A.

    2015-06-01

    Comparison of combined heat and power development trends in Russia and other countries allowed us to assess world CHP development trends for different regions of Russia. The paper presents a methodological approach to a comprehensive assessment of the effectiveness and extent of the CHP development proposed by ERI RAS. This approach is based on a unified representation of both energy consumption of all Russian cities and the sources of their supply. In addition, combined heat and power is considered in a complex relationship with other types of power generators and fuel industries. The applicability of this approach for the study of the development prospects of diverse CHP plants was shown. The presented methodical approach was used to develop draft scenarios of the Energy Strategy of Russia until 2035. The performed assessment of preferred application areas and effective extent of CHP development indicated the reasonability of continuing growth of CHP capacity and their role in the district heating system in Russia.

  2. Wireless power and data transmission strategies for next-generation capsule endoscopes

    NASA Astrophysics Data System (ADS)

    Puers, R.; Carta, R.; Thoné, J.

    2011-05-01

    Capsular endoscopy is becoming increasingly popular as an alternative to traditional gastro-intestinal (GI) examination techniques. However, the breakthrough of these devices is hindered by the limited amount of power that can be stored in a tiny pill. Most commercial devices use two watch batteries that can only provide an average power of 25 mW for about 6 h, certainly not sufficient for advanced robotic features. A dedicated inductive powering system, operating at 1 MHz to limit the human body absorption, has been developed which was proven to support the transfer of over 300 mW. The system relies on a condensed set of orthogonal ferrite coils, embedded in the capsule, and an external unit based on a Helmholtz coil driven by a class E amplifier. Control data can be sent through the inductive link by modulating the power carrier, whereas a dedicated high data rate RF link is used to transfer the images from the capsule to the base station. Besides evaluating the compatibility with radio transmission, several demonstrators were assembled combining the wireless powering system with various locomotion strategies and LED illumination. This paper describes the design and implementation of the inductive powering system, its combination with data transmission techniques and the testing activity with other capsule-dedicated modules.

  3. Power consumption evaluation of different fed-batch strategies for enzymatic hydrolysis of sugarcane bagasse.

    PubMed

    Corrêa, Luciano Jacob; Badino, Alberto Colli; Cruz, Antonio José Gonçalves

    2016-05-01

    The minimization of costs in the distillation step of lignocellulosic ethanol production requires the use of a high solids loading during the enzymatic hydrolysis to obtain a more concentrated glucose liquor. However, this increase in biomass can lead to problems including increased mass and heat transfer resistance, decreased cellulose conversion, and increased apparent viscosity with the associated increase in power consumption. The use of fed-batch operation offers a promising way to circumvent these problems. In this study, one batch and four fed-batch strategies for solids and/or enzyme feeding during the enzymatic hydrolysis of sugarcane bagasse were evaluated. Determinations of glucose concentration, power consumption, and apparent viscosity were made throughout the experiments, and the different strategies were compared in terms of energy efficiency (mass of glucose produced according to the energy consumed). The best energy efficiency was obtained for the strategy in which substrate and enzyme were added simultaneously (0.35 kg(glucose) kWh⁻¹). This value was 52% higher than obtained in batch operation. PMID:26899602

  4. Development and commercialization strategy for piezoelectric energy-harvesting power sources for gun-fired munitions

    NASA Astrophysics Data System (ADS)

    Rastegar, J.; Murray, R.

    2010-04-01

    A novel class of piezoelectric-based energy-harvesting power sources has been developed for gun-fired munitions and similar high-G applications. The power sources are designed to harvest energy primarily from the firing acceleration, but from in-flight vibratory motions as well. During the firing, a spring-mass element reacts to the axial acceleration, deforming and storing mechanical potential energy. After the projectile has exited the muzzle, the spring-mass element is free to vibrate, and the energy of the vibration is harvested using piezoelectric materials. These piezoelectric-based devices have been shown to produce enough electrical energy for many applications such as fuzing, and are able to eliminate the need for chemical batteries in many applications. When employed in fuzing applications, the developed power sources have the added advantage of providing augmented safety, since the fuzing electronics are powered only after the projectile has exited the muzzle and traveled a safe distance from the weapon platform. An overview of the development of these novel power sources is provided, especially designing and packaging for the high-G environment. Extensive laboratory and field testing has been performed on various prototypes; the methods and results of these experiments are presented. In addition to presenting the development and validation of this technology, methods for integrating the generators into different classes of projectiles are discussed along with strategies for manufacturing. This technology is currently validated to the extent that prototype devices have been successfully fired on-board actual gun-fired projectiles, demonstrating survivability and indicating performance. Strategies for designing the devices for a particular round and transitioning to commercialization are also discussed.

  5. Study of energy efficient supercritical coal-fired power plant dynamic responses and control strategies

    NASA Astrophysics Data System (ADS)

    Mohamed, Omar R. Ibrahim

    The world is facing the challenge of global warming and environment protection. On the other hand, the demand of electricity is growing fast due to economic growth and increase in population. Since the growth in demand is also a heavy factor in energy equations, then the renewable energy alone is not able to generate enough electricity to fill the gap within a short time of period. Therefore, fossil fuel such as coal fired power plants cannot be ruled out immediately due to their generation capacity and flexibility in load following. However, any new coal fired stations should be cleaner compared with traditional power plants. Supercritical power plants are one of the most suitable choices for environmental enhancement and higher efficiency. However, there has been an issue of whether or not to adopt this technology in the UK because it is not clear whether the performance for SC plants can satisfy the British Grid Code requirement. This thesis reports a study of dynamic responses of SC power plants through mathematical modelling, and simulation for Grid Code compliance. It also presents a new control strategy based on an alternative configuration of generalized predictive control for power plant control..

  6. Strategy for advancement of IRP in public power, Volume 2: Technical appendices

    SciTech Connect

    Garrick, C.J.

    1995-10-01

    NREL and subcontractor Garrick & Associates are conducting the Advancement of integrated resource planning (IRP) in Public Power Program, sponsored by DOE. The program is intended to develop a consistent strategy for DOE to advance IRP practices in the publicly and cooperatively owned utility sector. The IRP advancement program includes two major tasks: key participant involvement and strategy development. The Program`s initial task is to involve key public and cooperative utility organizations and their constituents in the development of the IRP advancement strategy. Key Participant Involvement is accomplished through two distinct subtasks: Needs Assessment and Steering Committee Involvement. The Needs Assessment identifies key participant needs, expectations, common interests, issues, and divergences that must be addressed by the IRP program. The results of this effort, which are presented in this {open_quotes}Needs Assessment Summary Report,{close_quotes} provide a foundation for the specific strategy development efforts conducted later in the IRP project. The remaining sections of this report present the approach to the Needs Assessment subtask and summarize the findings of this effort.

  7. Power and Energy Management Strategy for Solid State Transformer Interfaced DC Microgrid

    NASA Astrophysics Data System (ADS)

    Yu, Xunwei

    As a result of more and more applications of renewable energy into our ordinary life, how to construct a microgrid (MG) based on the distributed renewable energy resources and energy storages, and then to supply a reliable and flexible power to the conventional power system are the hottest topics nowadays. Comparing to the AC microgrid (AC MG), DC microgrid (DC MG) gets more attentions, because it has its own advantages, such as high efficiency, easy to integrate the DC energy sources and energy storages, and so on. Furthermore, the interaction between DC MG system and the distribution system is also an important and practical issue. In Future Renewable Electric Energy Delivery and Management Systems Center (FREEDM), the Solid State Transformer (SST) is built, which can transform the distribution system to the low AC and DC system directly (usually home application level). Thus, the SST gives a new promising solution for low voltage level MG to interface the distribution level system instead of the traditional transformer. So a SST interfaced DC MG is proposed. However, it also brings new challenges in the design and control fields for this system because the system gets more complicated, which includes distributed energy sources and storages, load, and SST. The purpose of this dissertation is to design a reliable and flexible SST interfaced DC MG based on the renewable energy sources and energy storages, which can operate in islanding mode and SST-enabled mode. Dual Half Bridge (DHB) is selected as the topology for DC/DC converter in DC MG. The DHB operation procedure and average model are analyzed, which is the basis for the system modeling, control and operation. Furthermore, two novel power and energy management strategies are proposed. The first one is a distributed energy management strategy for the DC MG operating in the SST-enabled mode. In this method, the system is not only in distributed control to increase the system reliability, but the power sharing

  8. Power and Energy Management Strategy for Solid State Transformer Interfaced DC Microgrid

    NASA Astrophysics Data System (ADS)

    Yu, Xunwei

    As a result of more and more applications of renewable energy into our ordinary life, how to construct a microgrid (MG) based on the distributed renewable energy resources and energy storages, and then to supply a reliable and flexible power to the conventional power system are the hottest topics nowadays. Comparing to the AC microgrid (AC MG), DC microgrid (DC MG) gets more attentions, because it has its own advantages, such as high efficiency, easy to integrate the DC energy sources and energy storages, and so on. Furthermore, the interaction between DC MG system and the distribution system is also an important and practical issue. In Future Renewable Electric Energy Delivery and Management Systems Center (FREEDM), the Solid State Transformer (SST) is built, which can transform the distribution system to the low AC and DC system directly (usually home application level). Thus, the SST gives a new promising solution for low voltage level MG to interface the distribution level system instead of the traditional transformer. So a SST interfaced DC MG is proposed. However, it also brings new challenges in the design and control fields for this system because the system gets more complicated, which includes distributed energy sources and storages, load, and SST. The purpose of this dissertation is to design a reliable and flexible SST interfaced DC MG based on the renewable energy sources and energy storages, which can operate in islanding mode and SST-enabled mode. Dual Half Bridge (DHB) is selected as the topology for DC/DC converter in DC MG. The DHB operation procedure and average model are analyzed, which is the basis for the system modeling, control and operation. Furthermore, two novel power and energy management strategies are proposed. The first one is a distributed energy management strategy for the DC MG operating in the SST-enabled mode. In this method, the system is not only in distributed control to increase the system reliability, but the power sharing

  9. Power allocation strategies to minimize energy consumption in wireless body area networks.

    PubMed

    Kailas, Aravind

    2011-01-01

    The wide scale deployment of wireless body area networks (WBANs) hinges on designing energy efficient communication protocols to support the reliable communication as well as to prolong the network lifetime. Cooperative communications, a relatively new idea in wireless communications, offers the benefits of multi-antenna systems, thereby improving the link reliability and boosting energy efficiency. In this short paper, the advantages of resorting to cooperative communications for WBANs in terms of minimized energy consumption are investigated. Adopting an energy model that encompasses energy consumptions in the transmitter and receiver circuits, and transmitting energy per bit, it is seen that cooperative transmission can improve energy efficiency of the wireless network. In particular, the problem of optimal power allocation is studied with the constraint of targeted outage probability. Two strategies of power allocation are considered: power allocation with and without posture state information. Using analysis and simulation-based results, two key points are demonstrated: (i) allocating power to the on-body sensors making use of the posture information can reduce the total energy consumption of the WBAN; and (ii) when the channel condition is good, it is better to recruit less relays for cooperation to enhance energy efficiency. PMID:22254777

  10. FERMI magnet power supplies: design strategies and five years of operational experience

    NASA Astrophysics Data System (ADS)

    Visintini, Roberto

    2015-05-01

    FERMI is the FEL-based light source in operation for external users since 2011 at the Elettra Research Center in Trieste, Italy. FERMI@Elettra is the name of the project for the construction and commissioning of this source. The design strategies adopted in the project had to consider the extremely close presence and the routine operation for users of the synchrotron-based source Elettra. There are more than 350 magnets and coils distributed along the linear accelerator, the two chains of undulators and the electron beam dump. Almost each magnetic element requires a dedicated DC power supply. Magnets, power supplies, and the connecting cables constitute a system, strongly interconnected with the remote control system, the machine and personnel safety system, and the infrastructure. All this has to fulfill the requirements from the particle physics specialists. We adopted a "systemic" approach in the design of new magnets and the re-use of the old ones, as well as the choice and the design of the associated power supplies. The commissioning of the systems started early 2010 and almost all magnet power supplies are in operation since then. During these 5 years, we introduced few minor upgrades and patches while the adopted solutions proved their soundness in terms of performance and reliability, causing very little downtime to the FERMI operations.

  11. Simple strategies for minimization of cooling water usage in binary power plants

    SciTech Connect

    Bliem, C.J.; Mines, G.L. )

    1989-01-01

    The geothermal resources which could be used for the production of electrical power in the United States are located for the most part in the semi-arid western regions of the country. The availability of ground or surface water in the quantity or quality desired for a conventional wet'' heat rejections system represents a barrier to the development of these resources with the binary cycle technology. This paper investigates some simple strategies to minimize the cooling water usage of binary power plants. The cooling water usage is reduced by increasing the thermal efficiency of the plant. Three methods of accomplishing this are considered here: increasing the average source temperature, by increasing the geofluid outlet temperature; decreasing pinch points on the heat rejection heat exchangers, increasing their size; and using internal recuperation within the cycle. In addition to the impact on water usage, the impact on cost-of-electricity is determined. The paper shows that some of these strategies can reduce the cooling water requirements 20 to 30% over that for a plant similar to the Heber Binary Plant, with a net reduction in the cost-of-electricity of about 15%. 13 refs., 4 figs., 3 tabs.

  12. Federal strategies to increase the implementation of combined heat and power technologies in the United States

    SciTech Connect

    Laitner, J.; Parks, W.; Schilling, J.; Scheer, R.

    1999-07-01

    Recent interest in combined heat and power (CHP) is providing momentum to efforts aimed at increasing the capacity of this highly-efficient technology. Factors driving this increase in interest include the need to increase the efficiency of the nation's electricity generation infrastructure, DOE Assistant Secretary Dan Reicher's challenge to double the capacity of CHP by 2010, the success of DOE's Advanced Turbine Systems Program in supporting ultra-efficient CHP technologies, and the necessity of finding cost-effective solutions to address climate change and air quality issues. The federal government is committed to increasing the penetration of CHP technologies in the US. The ultimate goal is to build a competitive market for CHP in which policies and regulations support the implementation of a full suite of technologies for multiple applications. Specific actions underway at the federal level include technology strategies to improve CHP data collection and assessment and work with industry to encourage the development of advanced CHP technologies. Policy strategies include changes to federal environmental permitting procedures including CHP-friendly strategies in federal restructuring legislation, supporting tax credits and changes to depreciation requirements as economic incentives to CHP, working with industry to leverage resources in the development of advanced CHP technologies, educating state officials about the things they can do to encourage CHP, and increasing awareness about the benefits of CHP and the barriers limiting its increased implementation.

  13. A new coordinated control strategy for boiler-turbine system of coal-fired power plant

    SciTech Connect

    Li, S.Y.; Liu, H.B.; Cai, W.J.; Soh, Y.C.; Xie, L.H.

    2005-11-01

    This paper presents the new development of the boiler-turbine coordinated control strategy using fuzzy reasoning and autotuning techniques. The boiler-turbine system is a very complex process that is a multivariable, nonlinear, slowly time-varying plant with large settling time and a lot of uncertainties. As there exist strong couplings between the main steam pressure control loop and the power output control loop in the boiler-turbine unit with large time-delay and uncertainties, automatic coordinated control of the two loops is a very challenging problem. This paper presents a new coordinated control strategy (CCS) which is organized into two levels: a basic control level and a high supervision level. Proportional-integral derivative (PID) type controllers are used in the basic level to perform basic control functions while the decoupling between two control loops can be realized in the high level. A special subclass of fuzzy inference systems, called the Gaussian partition with evenly (GPE) spaced midpoints systems, is used to self-tune the main steam pressure PID controller's parameters online based on the error signal and its first difference, aimed at overcoming the uncertainties due to changing fuel calorific value, machine wear, contamination of the boiler heating surfaces and plant modeling errors. For the large variation of operating condition, a supervisory control level has been developed by autotuning technique. The developed CCS has been implemented in a power plant in China, and satisfactory industrial operation results demonstrate that the proposed control strategy has enhanced the adaptability and robustness of the process. Indeed, better control performance and economic benefit have been achieved.

  14. Coping with Stress and Types of Burnout: Explanatory Power of Different Coping Strategies

    PubMed Central

    Montero-Marin, Jesus; Prado-Abril, Javier; Piva Demarzo, Marcelo Marcos; Gascon, Santiago; García-Campayo, Javier

    2014-01-01

    Background Burnout occurs when professionals use ineffective coping strategies to try to protect themselves from work-related stress. The dimensions of ‘overload’, ‘lack of development’ and ‘neglect’, belonging to the ‘frenetic’, ‘under-challenged’ and ‘worn-out’ subtypes, respectively, comprise a brief typological definition of burnout. The aim of the present study was to estimate the explanatory power of the different coping strategies on the development of burnout subtypes. Methods This was a cross-sectional survey with a random sample of university employees, stratified by occupation (n = 429). Multivariate linear regression models were constructed between the ‘Burnout Clinical Subtypes Questionnaire’, with its three dimensions –overload, lack of development and neglect– as dependent variables, and the ‘Coping Orientation for Problem Experiences’, with its fifteen dimensions, as independent variables. Adjusted multiple determination coefficients and beta coefficients were calculated to evaluate and compare the explanatory capacity of the different coping strategies. Results The ‘Coping Orientation for Problem Experiences’ subscales together explained 15% of the ‘overload’ (p<0.001), 9% of the ‘lack of development’ (p<0.001), and 21% of the ‘neglect’ (p<0.001). ‘Overload’ was mainly explained by ‘venting of emotions’ (Beta = 0.34; p<0.001); ‘lack of development’ by ‘cognitive avoidance’ (Beta = 0.21; p<0.001); and ‘neglect’ by ‘behavioural disengagement’ (Beta = 0.40; p<0.001). Other interesting associations were observed. Conclusions These findings further our understanding of the way in which the effectiveness of interventions for burnout may be improved, by influencing new treatments and preventive programmes using features of the strategies for handling stress in the workplace. PMID:24551223

  15. Implementation strategies for load center automation on the space station module/power management and distribution testbed

    NASA Technical Reports Server (NTRS)

    Watson, Karen

    1990-01-01

    The Space Station Module/Power Management and Distribution (SSM/PMAD) testbed was developed to study the tertiary power management on modules in large spacecraft. The main goal was to study automation techniques, not necessarily develop flight ready systems. Because of the confidence gained in many of automation strategies investigated, it is appropriate to study, in more detail, implementation strategies in order to find better trade-offs for nearer to flight ready systems. These trade-offs particularly concern the weight, volume, power consumption, and performance of the automation system. These systems, in their present implementation are described.

  16. Adaptive Control for Buck Power Converter Using Fixed Point Inducting Control and Zero Average Dynamics Strategies

    NASA Astrophysics Data System (ADS)

    Hoyos Velasco, Fredy Edimer; García, Nicolás Toro; Garcés Gómez, Yeison Alberto

    In this paper, the output voltage of a buck power converter is controlled by means of a quasi-sliding scheme. The Fixed Point Inducting Control (FPIC) technique is used for the control design, based on the Zero Average Dynamics (ZAD) strategy, including load estimation by means of the Least Mean Squares (LMS) method. The control scheme is tested in a Rapid Control Prototyping (RCP) system based on Digital Signal Processing (DSP) for dSPACE platform. The closed loop system shows adequate performance. The experimental and simulation results match. The main contribution of this paper is to introduce the load estimator by means of LMS, to make ZAD and FPIC control feasible in load variation conditions. In addition, comparison results for controlled buck converter with SMC, PID and ZAD-FPIC control techniques are shown.

  17. Simulation of gas and water management strategies in PEM fuel cells for UAV power

    NASA Astrophysics Data System (ADS)

    Wade, Nasir; Smith, Sonya

    2008-11-01

    Proton exchange membrane fuel cells (PEMFC) a involve a number of complex fluid phenomena that are not well understood. The focus of this research is to design a fuel cell that addresses the issues of gas and water management for the power requirements for an Unmanned Arial Vehicle (UAV). Often in conventional stack design, PEM fuel cells are connected electrically in series to create the desired voltage and feed from a common fuel or oxidant stream. This method of fueling, often leads to an uneven distribution of fluid within the stack, causing issues such as cell flooding, dehydration of membrane and inevitably poor fuel cell performance. Generally, fuel cell designers and developers incorporate higher stoichiometric gas flow rates and use flow field designs with high pressure drops in order to counter this phenomenon, ensuring even gas distribution. This method, although effective for water removal, leads to added cost and higher levels of wasted fuel. Using a simulation based approach we demonstrate the feasibility and effectiveness of an individual fuel and oxidant flow distribution, integrated with an individual sequential exhaust technique for a 6-8 cell stack which outputs 300-500 Watts of power. Using varied exhaust configurations the most optimal active gas management strategy will be outlined and recommended to give the best stack performance.

  18. Xenon Acquisition Strategies for High-Power Electric Propulsion NASA Missions

    NASA Technical Reports Server (NTRS)

    Herman, Daniel A.; Unfried, Kenneth G.

    2015-01-01

    The benefits of high-power solar electric propulsion (SEP) for both NASA's human and science exploration missions combined with the technology investment from the Space Technology Mission Directorate have enabled the development of a 50kW-class SEP mission. NASA mission concepts developed, including the Asteroid Redirect Robotic Mission, and those proposed by contracted efforts for the 30kW-class demonstration have a range of xenon propellant loads from 100's of kg up to 10,000 kg. A xenon propellant load of 10 metric tons represents greater than 10% of the global annual production rate of xenon. A single procurement of this size with short-term delivery can disrupt the xenon market, driving up pricing, making the propellant costs for the mission prohibitive. This paper examines the status of the xenon industry worldwide, including historical xenon supply and pricing. The paper discusses approaches for acquiring on the order of 10 MT of xenon propellant considering realistic programmatic constraints to support potential near-term NASA missions. Finally, the paper will discuss acquisitions strategies for mission campaigns utilizing multiple high-power solar electric propulsion vehicles requiring 100's of metric tons of xenon over an extended period of time where a longer term acquisition approach could be implemented.

  19. Advanced management strategies for remote-area power-supply systems

    NASA Astrophysics Data System (ADS)

    Newnham, R. H.; Baldsing, W. G. A.

    An operating strategy based on partial-state-of-charge (PSoC) operation has been developed for a remote-area power-supply (RAPS) system in Peru. The facility will power an entire village and comprises a photovoltaic array, a bank of gel valve-regulated lead-acid (VRLA) batteries, a diesel generator, and a sophisticated control system. The PSoC schedule involves operation below a full state-of-charge (SoC) for 28 days, followed by an equalization charge. The schedule has been evaluated by operating a 24 V battery bank under simulated RAPS conditions in the laboratory. It is found that operation between 58 and 83% SoC causes the negative-plate potentials to move to significantly more negative values during charging as the PSoC duty progresses. This behaviour is undesirable, because it can lead to the activation of a preset limit and a subsequent reduction in system efficiency. Lowering the PSoC window to 47-72% SoC or 40-65% SoC during the 28-day cycle is found to stabilize the negative-plate potentials. The behaviour of the negative plates in gel batteries is very similar to that observed for absorptive glass mat (AGM) designs of VRLA batteries operated in hybrid electric vehicles.

  20. The global rise in methane 2007-present: isotopic constraints from Ascension and Alert. Is a significant change occurring?

    NASA Astrophysics Data System (ADS)

    Nisbet, Euan G.; Manning, Martin R.; Lowry, David; Fisher, Rebecca E.; France, James; Brownlow, Rebecca

    2016-04-01

    Since 2007, atmospheric methane has risen globally by about 6 ppb a year (NOAA data), though with strong year to year variations, after a prolonged approach to equilibrium in the 1980s and 1990s. Much of this growth has been driven from the tropics, especially in the Southern Hemisphere, though with brief episodes of strong growth also in the Arctic in 2007, and in the Northern Hemisphere's low temperate latitudes. Global growth was about 13±1 ppb in 2014 and continued strongly through 2015 (NOAA data). The renewed growth in total methane burden has been accompanied by a significant shift in δ13CCH4 ratio to more 13C depleted values, which began simultaneously with the start of the rise, and has been broadly sustained, although there have also been large short term positive anomalies in δ13CCH4 occurring in both hemispheres. On Ascension island (8oS), δ13CCH4 values through into 2015 have stabilised around 0.2‰ more negative than in 2007-8. Measurements from Cape Point (34oS), and Alert (82oN) show similar patterns, as do NOAA-INSTAAR results from S. Pole. This isotopic trend is quite different from the trend of the 20th century, and implies current growth is driven by biogenic sources, not direct anthropogenic emissions. A budget analysis of both methane mole fraction and δ13CCH4 ratio has been used to investigate patterns. It is unlikely that the growth was driven by reductions in the OH sink, as such scenarios are hard to reconcile with the isotopic record. Increased anthropogenic emissions, from coal and gas leaks or fires, would tend to shift isotopic values to less 13C depleted values, the opposite of observations. The most likely explanation for the change is thus sustained growth in low latitude and southern biogenic sources, probably mainly from tropical wetlands, forests and savannas, with a possible contribution also from ruminants. In total, over the 9 year 2007- 2015 period, methane growth has been about 50-60 ppb, and continuing. The broad

  1. An Investigation of Iranian EFL Learners' Use of Politeness Strategies and Power Relations in Disagreement across Different Proficiency Levels

    ERIC Educational Resources Information Center

    Behnam, Biook; Niroomand, Masoumeh

    2011-01-01

    The speech act of disagreement has been one of the speech acts that receives the least attention in the field of pragmatics. This study investigates the ways power relations influence politeness strategies in disagreement. In order to determine whether and to what extent the realization of the speech act of disagreeing and the of appropriate…

  2. Power and Liberty: A Long-Term Course Planning Strategy to Encourage the Contextualization of Events in American History

    ERIC Educational Resources Information Center

    Endacott, Jason L.

    2011-01-01

    Applying a consistent historical theme throughout a social studies course is an effective long-term planning strategy that can promote student engagement, retention of information, and contextualized knowledge of history's continuity and change. This article demonstrates how one such theme, power and liberty, might be incorporated into a secondary…

  3. Evaluations of a Date Rape Situation: Effects of Victim's Power Strategy, Rape Outcome, and Sex of Subject.

    ERIC Educational Resources Information Center

    Stevens, Laura E.; DeLamarter, William A.

    According to a recent study a rape occurs every 7 minutes and 60% of those rapes happen on dates. This study examined the impact of assault outcomes (rape, avoidance) and victim's power strategy (direct/bilateral, indirect/unilateral) on male and female evaluations of a date rape situation. College students (N=121) listened to a taped dialogue and…

  4. Anatomy of power system blackouts and preventive strategies by rational supervision and control of protection systems

    SciTech Connect

    Phadke, A.G.; Horowitz, S.H.; Thorp, J.S.

    1995-01-01

    This report establishes the concept of hidden failures in relays and associated devices used for the protection of electric power systems. A hidden failure is a defect such as a component failure, inappropriate setting or incorrect external connection that remains undetected until some other system event causes the hidden failure to initiate a cascading outage. Associated with the study of hidden failures, this report examines the impact such defects might have by defining regions of vulnerability. A region of vulnerability is the area of the system in which a hidden failure will be activated. To determine such areas we have established criteria associated with load flows and steady-state stability, such as lack of convergence, and employed a technique known as importance sampling in which the simulation is done with the probabilities altered so that the rare event happens more frequently. Our purpose is to provide a framework for further research into relay vulnerability, possibly using adaptive techniques to eliminate hidden defects. We believe control strategies can be developed to prevent cascading normal operations from developing into severe outages by extending the present criteria using steady-state stability and load flow studies into the area of transient stability, and further research into importance sampling would provide significant benefits in evaluating corrective actions.

  5. Using System Dynamics to Define, Study, and Implement Smart Control Strategies on the Electric Power Grid

    SciTech Connect

    Lyle G. Roybal; Robert F Jeffers

    2013-07-01

    The United States electric power grid is the most complex and expansive control system in the world. Local generation control occurs at individual units based on response time and unit economics, larger regional control coordinates unit response to error conditions, and high level large-area regional control is ultimately administered by a network of humans guided by economic and resiliency related factors. Under normal operating conditions, the grid is a relatively slow moving entity that exhibits high inertia to outside stimuli, and behaves along repeatable diurnal and seasonal patterns. However, that paradigm is quickly changing because of the increasing implementation of renewable generation sources. Renewable generators by nature cannot be tightly controlled or scheduled. They appear like a negative load to the system with all of the variability associated with load on a larger scale. Also, grid-reactive loads (i.e. smart devices) can alter their consumption based on price or demand rules adding more variability to system behavior. This paper demonstrates how a systems dynamic modeling approach capable of operating over multiple time scales, can provide valuable insight into developing new “smart-grid” control strategies and devices needed to accommodate renewable generation and regulate the frequency of the grid.

  6. Practical strategies for leading an effective group. Balancing power, participation, and problem-solving.

    PubMed

    Matejka, K; South, J

    1989-01-01

    How can you more effectively lead your group? In today's world of rapid technological and social change, where Thriving on Chaos is the best-selling management book, group work is not a luxury, but a necessity. Although some employees naturally prefer working alone, we all must function effectively in group settings. To lead a group well, the leader needs to be sensitive to three critical variables: participation, power, and problem-solving. Balancing these processes becomes the key to effective performance. The leader must pay close attention to what is happening within the group and make specific interventions to more effectively distribute the skills and energies of the members. Making every group member a significant contributor takes skill but results in more accurate decisions and greater commitment. The group leader is the facilitator, charged with managing the problem-solving process and leading the group to the most productive, objective outcome. This article supplies many practical, corrective strategies for moving your group in a more positive direction. PMID:10303698

  7. Strategy for Migration of Traditional to Hybrid Control Boards in a Nuclear Power Plant

    SciTech Connect

    Boring, Ronald Laurids; Joe, Jeffrey Clark; Ulrich, Thomas Anthony

    2014-07-01

    This strategy document describes the NUREG-0711 based human factors engineering (HFE) phases and associated elements required to support design, verification and validation (V&V), and implementation of new digital control room elements in a legacy analog main control room (MCR). Information from previous planning and analysis work serves as the foundation for creating a human-machine interface (HMI) specification for distributed control systems (DCSs) to be implemented as part of nuclear power plant (NPP) modernization. This document reviews ways to take the HMSI specification and use it when migrating legacy displays or designing displays with new functionality. These displays undergo iterative usability testing during the design phase and then an integrated system validation (ISV) in the full-scope control room training simulator. Following successful demonstration of operator performance using the systems during the ISV, the new DCS is implemented at the plant, first in the training simulator and then in the MCR. This document concludes with a sample project plan, including a 15-month timeline from DCS design through implementation. Included is a discussion of how the U.S. Department of Energy’s Human System Simulation Laboratory (HSSL) can be used to support design and V&V activities. This report completes a Level 4 (M4) milestone under the U.S. Department of Energy’s (DOE’s) Light Water Reactor Sustainability (LWRS) Program.

  8. Interplay between magmatic accretion, spreading asymmetry and detachment faulting at a segment end: Crustal structure south of the Ascension Fracture Zone

    NASA Astrophysics Data System (ADS)

    Bialas, Jörg; Dannowski, Anke; Reston, Timothy J.

    2015-12-01

    A wide-angle seismic section across the Mid-Atlantic Ridge just south of the Ascension transform system reveals laterally varying crustal thickness, and to the east a strongly distorted Moho that appears to result from slip along a large-offset normal fault, termed an oceanic detachment fault. Gravity modelling supports the inferred crustal structure. We investigate the interplay between magmatism, detachment faulting and the changing asymmetry of crustal accretion, and consider several possible scenarios. The one that appears most likely is remarkably simple: an episode of detachment faulting which accommodates all plate divergence and results in the westward migration of the ridge axis, is interspersed with dominantly magmatic and moderately asymmetric (most on the western side) spreading which moves the spreading axis back towards the east. Following the runaway weakening of a normal fault and its development into an oceanic detachment fault, magma both intrudes the footwall to the fault, producing a layer of gabbro (subsequently partially exhumed).

  9. New high proper motion stars with declinations between -5(deg) and -30(deg) , and right ascensions between 13h 30m and 24h

    NASA Astrophysics Data System (ADS)

    Wroblewski, H.; Costa, E.

    1999-10-01

    Proper motions, positions, finding charts and magnitudes are given for 293 newly discovered stars with proper motions larger than 0.15 arcsec/year. They are located between -5(deg) and -30(deg) in declination, and 13h 30m and 24h in right ascension. Their blue photographic magnitudes range from approximately 13.0 to 18.5. Six stars of the above sample have proper motions larger than 0.4 (0.401 to 0.534) arcsec/year. An estimated precision level between 7 and 13 mas/year was achieved for the proper motions. Table~2 is only available in electronic form at the CDS via anonymous ftp 130.79.128.5 or http://cdsweb.u-strasbg.fr/Abstract.html and figures~2 are available in the on-line edition of the journal at http://www.edpsciences.com

  10. Development of energy management system based on a power sharing strategy for a fuel cell-battery-supercapacitor hybrid tramway

    NASA Astrophysics Data System (ADS)

    Li, Qi; Chen, Weirong; Liu, Zhixiang; Li, Ming; Ma, Lei

    2015-04-01

    A hybrid powertrain configuration based on a proton exchange membrane (PEMFC), a battery and a supercapacitor (SC) is designed without grid connection for the LF-LRV tramway. In order to avoid rapid changes of power demand and achieve high efficiency without degrading the mechanism performance, a power sharing strategy based on a combination of fuzzy logic control (FLC) and Haar wavelet transform (Haar-WT) is proposed for an energy management system of the hybrid tramway. The results demonstrate that the proposed energy management system is able to ensure the major positive portion of the low frequency components of power demand can be deals with the PEMFC. The battery can help provide a portion of the positive low frequency components of power demand to reduce the PEMFC burden while the SC bank can supply all the high frequency components which could damage the PEMFC membrane. Therefore, the energy management system of high-power hybrid tramway is able to guarantee a safe operating condition with transient free for the PEMFC and extend the lifetime of each power source. Finally, the comparisons with other control strategies verify that the proposed energy management system can achieve better energy efficiency of the overall hybrid tramway.

  11. Strategies for the Use of Tidal Stream Currents for Power Generation

    NASA Astrophysics Data System (ADS)

    Orhan, Kadir; Mayerle, Roberto

    2015-04-01

    Indonesia is one of the priority countries in Southeast Asia for the development of ocean renewable energy facilities and The National Energy Council intends to increase the role of ocean energy significantly in the energy mix for 2010-2050. To this end, the joint German-Indonesian project "Ocean Renewable Energy ORE-12" aims at the identification of marine environments in the Indonesian Archipelago, which are suitable for the efficient generation of electric power by converter facilities. This study, within the ORE-12 project, is focused on the tidal stream currents on the straits between the Indian Ocean and Flores Sea to estimate the energy potentials and to develop strategies for producing renewable energy. FLOW module of Delft3D has been used to run hydrodynamic models for site assessment and design development. In site assessment phase, 2D models have been operated for a-month long periods and with a resolution of 500 m. Later on, in design development phase, detailed 3D models have been developed and operated for three-month long periods and with a resolution of 50 m. Bathymetric data for models have been obtained from the GEBCO_08 Grid and wind data from the Global Forecast System of NOAA's National Climatic Data Center. To set the boundary conditions of models, tidal forcing with 11 harmonic constituents was supplied from TPXO Indian Ocean Atlas (1/12° regional model) and data from HYCOM+NCODA Global 1/12° Analysis have been used to determine salinity and temperature on open boundaries. After the field survey is complete, water level time-series supplied from a tidal gauge located in the domain of interest (8° 20΄ 9.7" S, 122° 54΄ 51.9" E) have been used to verify the models and then energy potentials of the straits have been estimated. As a next step, correspondence between model outputs and measurements taken by the radar system of TerraSAR-X satellite (DLR) will be analysed. Also for the assessment of environmental impacts caused by tidal stream

  12. Condom Use Negotiation in Heterosexual African-American Adults: Responses to Types of Social Power-Based Strategies

    PubMed Central

    Otto-Salaj, Laura L.; Reed, Barbara; Brondino, Michael J.; Gore-Felton, Cheryl; Kelly, Jeffrey A.; Stevenson, L. Yvonne

    2009-01-01

    Little research has been performed on how people respond to different strategies to negotiate condom use in sexual situations, and whether certain strategies tend to be perceived as more or less effective in condom use negotiation. This study examined gender differences and preferences in the use of and response to six different styles of condom use negotiation with a hypothetical sexual partner of the opposite gender. Participants were 51 heterosexually-active African-American men and women between the ages of 18 and 35, attending an inner-city community center. Study participants completed a semi-structured qualitative interview in which they were presented with six negotiation strategies —coercive, reward, legitimate, expert, referent, and informational--based on Raven’s 1992 Power/Interaction Model of Interpersonal Influence. Results showed that women participants responded best to referent, reward, and legitimate strategies, and worst to informational tactics. Men participants responded best to reward strategies, and worst to coercion to use condoms. Further, responses given by a subset of both women—and, to a greater extent, men--indicated that use of negotiation tactics involving coercion to use condoms may result in negative or angry reactions. Finally, response to strategies may vary with the value of the relationship as viewed by the target of negotiation. Implications for HIV prevention programs and media campaigns are discussed. PMID:18569536

  13. General volume sizing strategy for thermal storage system using phase change material for concentrated solar thermal power plant

    DOE PAGESBeta

    Xu, Ben; Li, Peiwen; Chan, Cholik; Tumilowicz, Eric

    2014-12-18

    With an auxiliary large capacity thermal storage using phase change material (PCM), Concentrated Solar Power (CSP) is a promising technology for high efficiency solar energy utilization. In a thermal storage system, a dual-media thermal storage tank is typically adopted in industry for the purpose of reducing the use of the heat transfer fluid (HTF) which is usually expensive. While the sensible heat storage system (SHSS) has been well studied, a dual-media latent heat storage system (LHSS) still needs more attention and study. The volume sizing of the thermal storage tank, considering daily cyclic operations, is of particular significance. In thismore » paper, a general volume sizing strategy for LHSS is proposed, based on an enthalpy-based 1D transient model. One example was presented to demonstrate how to apply this strategy to obtain an actual storage tank volume. With this volume, a LHSS can supply heat to a thermal power plant with the HTF at temperatures above a cutoff point during a desired 6 hours of operation. This general volume sizing strategy is believed to be of particular interest for the solar thermal power industry.« less

  14. General volume sizing strategy for thermal storage system using phase change material for concentrated solar thermal power plant

    SciTech Connect

    Xu, Ben; Li, Peiwen; Chan, Cholik; Tumilowicz, Eric

    2014-12-18

    With an auxiliary large capacity thermal storage using phase change material (PCM), Concentrated Solar Power (CSP) is a promising technology for high efficiency solar energy utilization. In a thermal storage system, a dual-media thermal storage tank is typically adopted in industry for the purpose of reducing the use of the heat transfer fluid (HTF) which is usually expensive. While the sensible heat storage system (SHSS) has been well studied, a dual-media latent heat storage system (LHSS) still needs more attention and study. The volume sizing of the thermal storage tank, considering daily cyclic operations, is of particular significance. In this paper, a general volume sizing strategy for LHSS is proposed, based on an enthalpy-based 1D transient model. One example was presented to demonstrate how to apply this strategy to obtain an actual storage tank volume. With this volume, a LHSS can supply heat to a thermal power plant with the HTF at temperatures above a cutoff point during a desired 6 hours of operation. This general volume sizing strategy is believed to be of particular interest for the solar thermal power industry.

  15. An alternative strategy for low specific power reactors to power interplanetary spacecraft, based on exploiting lasers and lunar resources

    SciTech Connect

    Logan, B.G.

    1989-02-02

    A key requirement setting the minimum electric propulsion performance (specific power ..cap alpha../sub e/ = kW/sub e//kg) for manned missions to Mars is the maximum allowable radiation dose to the crew during the long transits between Earth and Mars. Penetrating galactic cosmic rays and secondary neutron showers give about 0.1-rem/day dose, which only massive shielding (e.g., a meter of concrete) can reduce significantly. With a humane allowance for cabin space, the shielding mass becomes so large that it prohibitively escalates the propellant consumption required for reasonable trip times. This paper covers various proposed methods for using reactor power to propel spacecraft. 7 refs., 6 figs., 1 tab.

  16. Light Water Reactor Sustainability Program Power Uprate Research and Development Strategy

    SciTech Connect

    Hongbin Zhang

    2011-09-01

    The economic incentives for low-cost electricity generation will continue to drive more plant owners to identify safe and reliable methods to increase the electrical power output of the current nuclear power plant fleet. A power uprate enables a nuclear power plant to increase its electrical output with low cost. However, power uprates brought new challenges to plant owners and operators. These include equipment damage or degraded performance, and unanticipated responses to plant conditions, etc. These problems have arisen mainly from using dated design and safety analysis tools and insufficient understanding of the full implications of the proposed power uprate or from insufficient attention to detail during the design and implementation phase. It is essential to demonstrate that all required safety margins have been properly retained and the existing safety level has been maintained or even increased, with consideration of all the conditions and parameters that have an influence on plant safety. The impact of the power uprate on plant life management for long term operation is also an important issue. Significant capital investments are required to extend the lifetime of an aging nuclear power plant. Power uprates can help the plant owner to recover the investment costs. However, plant aging issues may be aggravated by the power uprate due to plant conditions. More rigorous analyses, inspections and monitoring systems are required.

  17. Dynamic analysis of the Maglev system using controlled-PM electromagnets and robust zero-power-control strategy

    SciTech Connect

    Tzeng, Y.K.; Wang, T.C.

    1995-11-01

    This paper presents a rigorous dynamic analysis for the Maglev system with controlled-PM electromagnets and robust zero-power-control strategy. A variable structure control (VSC) theory using new reaching law method is applied to the robust controller synthesis for reducing the control-voltage chattering and enhancing the suspension stability. Analytical expressions of the rms gap variation and the average regulation power loss under the excitation of random guideway irregularity are derived on the basis of this new control scheme by using frequency-domain approach. The power spectral density (PSD) method and the discrete frequency method of modelling the guideway roughness are both adopted to evaluate the overall vehicle ride dynamics. Numerical results gained from both approaches verify the feasibility and the superiority of applying this novel Maglev scheme to high speed transportation.

  18. A decision tree-based on-line preventive control strategy for power system transient instability prevention

    NASA Astrophysics Data System (ADS)

    Xu, Yan; Dong, Zhao Yang; Zhang, Rui; Wong, Kit Po

    2014-02-01

    Maintaining transient stability is a basic requirement for secure power system operations. Preventive control deals with modifying the system operating point to withstand probable contingencies. In this article, a decision tree (DT)-based on-line preventive control strategy is proposed for transient instability prevention of power systems. Given a stability database, a distance-based feature estimation algorithm is first applied to identify the critical generators, which are then used as features to develop a DT. By interpreting the splitting rules of DT, preventive control is realised by formulating the rules in a standard optimal power flow model and solving it. The proposed method is transparent in control mechanism, on-line computation compatible and convenient to deal with multi-contingency. The effectiveness and efficiency of the method has been verified on New England 10-machine 39-bus test system.

  19. Impact of power allocation strategies in long-haul few-mode fiber transmission systems.

    PubMed

    Rafique, Danish; Sygletos, Stylianos; Ellis, Andrew D

    2013-05-01

    We report for the first time on the limitations in the operational power range of few-mode fiber based transmission systems, employing 28 Gbaud quadrature phase shift keying transponders, over 1,600 km. It is demonstrated that if an additional mode is used on a preexisting few-mode transmission link, and allowed to optimize its performance, it will have a significant impact on the pre-existing mode. In particular, we show that for low mode coupling strengths (weak coupling regime), the newly added variable power mode does not considerably impact the fixed power existing mode, with performance penalties less than 2dB (in Q-factor). On the other hand, as mode coupling strength is increased (strong coupling regime), the individual launch power optimization significantly degrades the system performance, with penalties up to ~6 dB. Our results further suggest that mutual power optimization, of both fixed power and variable power modes, reduces power allocation related penalties to less than 3 dB, for any given coupling strength, for both high and low differential mode delays. PMID:23669937

  20. Fuzzy based power factor improvement strategy for a multiple connected AC-DC converter fed drive

    NASA Astrophysics Data System (ADS)

    Radhakrishnan, N.; Muthiah, Ramaswamy

    2012-01-01

    The main focus of this paper is to design a Fuzzy based control algorithm to realize an improvement in the input power factor of a multiple connected AC-DC converter fed drive system. It incorporates the role of fuzzy inference principles to generate appropriate PWM pulses for the power switches at the second stage of the power module. The philosophy is developed, with a view to reshape the input current phasor and enables it to align with the supply voltage wave in the perspective of improving the input power factor. The closed loop scheme evaluated using MATLAB based simulation exhibits an enhancement in supply power factor over a range of operating loads in addition to illustrating the speed regulating capability of the drive.

  1. Toward the last frontier - A strategy for the evolutionary development of space nuclear power systems

    NASA Technical Reports Server (NTRS)

    Bennett, Gary L.

    1992-01-01

    A number of exciting mission opportunities are being considered for the 21st century, including advanced robotic science missions to the outer planets and beyond, human exploration of the Moon and Mars, and advanced space transportation systems. All of these missions will require some form of nuclear power; however, it is clear that current budgetary constraints preclude developing many different types of space nuclear power systems. This paper reviews the specific civil space missions which have been identified, the power levels and lifetimes required, and the technologies available. From this an evolutionary space nuclear power program is developed which builds upon the experience of radioisotope thermoelectric generators, dynamic isotope power systems, and space nuclear reactors. It is strongly suggested that not only does this approach make technical and budgetary sense but that it is consistent with the normal development of new technologies.

  2. Conceptual Design and Optimal Power Control Strategy for AN Eco-Friendly Hybrid Vehicle

    NASA Astrophysics Data System (ADS)

    Nasiri, N. Mir; Chieng, Frederick T. A.

    2011-06-01

    This paper presents a new concept for a hybrid vehicle using a torque and speed splitting technique. It is implemented by the newly developed controller in combination with a two degree of freedom epicyclic gear transmission. This approach enables optimization of the power split between the less powerful electrical motor and more powerful engine while driving a car load. The power split is fundamentally a dual-energy integration mechanism as it is implemented by using the epicyclic gear transmission that has two inputs and one output for a proper power distribution. The developed power split control system manages the operation of both the inputs to have a known output with the condition of maintaining optimum operating efficiency of the internal combustion engine and electrical motor. This system has a huge potential as it is possible to integrate all the features of hybrid vehicle known to-date such as the regenerative braking system, series hybrid, parallel hybrid, series/parallel hybrid, and even complex hybrid (bidirectional). By using the new power split system it is possible to further reduce fuel consumption and increase overall efficiency.

  3. Comparison of speech processing strategies for the design of an ultra low-power analog bionic ear.

    PubMed

    Sawigun, Chutham; Ngamkham, Wannaya; Serdijn, Wouter A

    2010-01-01

    Miniaturizing area and power consumptions of cochlear prosthetic devices is strongly required for full implantation. In this paper, several speech encoding strategies are studied and compared in order to find a compact speech processor that allows for full implantation and is able to convey both time and frequency components of the incoming speech to a set of electrical pulse stimuli. The study covers the widely recognized continuous time interleaved sampling (CIS) and strategies that convey the temporal fine structure (TFS), including race-to-spike asynchronous interleaved sampling (AIS), phase-locking (PL) using zero-crossing detection (ZCD), and PL using a peak-picking (PP) technique. To estimate the performances of the four systems, a spike-based reconstruction algorithm is employed to retrieve the original sounds after being processed by different strategies. The correlation factors between the reconstructed and original signals imply that strategies that convey TFS outperform CIS. Among them, the peak picking technique combines good performance with great compactness since envelope detectors are not required. PMID:21096335

  4. About the strategy for development of the Russian power engineering (after ten years)

    NASA Astrophysics Data System (ADS)

    Batenin, V. M.; Zeigarnik, Yu. A.; Maslennikov, V. M.

    2012-04-01

    The situation that arose in the Russian power industry after restructuring the RAO UES of Russia is briefly analyzed. Special emphasis is placed on the fact that it is almost impossible to introduce innovations. Insolvency of directly copying foreign trends in development of power engineering is demonstrated. Several particular proposals aimed at improving the existing situation are stated that suggest raising the role of the State in managing the energy sector of the national economy.

  5. Optimization strategies for the vulnerability analysis of the electric power grid.

    SciTech Connect

    Meza, Juan C.; Pinar, Ali; Lesieutre, Bernard; Donde, Vaibhav

    2009-03-01

    Identifying small groups of lines, whose removal would cause a severe blackout, is critical for the secure operation of the electric power grid. We show how power grid vulnerability analysis can be studied as a mixed integer nonlinear programming (minlp) problem. Our analysis reveals a special structure in the formulation that can be exploited to avoid nonlinearity and approximate the original problem as a pure combinatorial problem. The key new observation behind our analysis is the correspondence between the Jacobian matrix (a representation of the feasibility boundary of the equations that describe the flow of power in the network) and the Laplacian matrix in spectral graph theory (a representation of the graph of the power grid). The reduced combinatorial problem is known as the network inhibition problem, for which we present a mixed integer linear programming formulation. Our experiments on benchmark power grids show that the reduced combinatorial model provides an accurate approximation, to enable vulnerability analyses of real-sized problems with more than 10,000 power lines.

  6. Optimization Strategies for the Vulnerability Analysis of the Electric Power Grid

    SciTech Connect

    Pinar, A.; Meza, J.; Donde, V.; Lesieutre, B.

    2007-11-13

    Identifying small groups of lines, whose removal would cause a severe blackout, is critical for the secure operation of the electric power grid. We show how power grid vulnerability analysis can be studied as a mixed integer nonlinear programming (MINLP) problem. Our analysis reveals a special structure in the formulation that can be exploited to avoid nonlinearity and approximate the original problem as a pure combinatorial problem. The key new observation behind our analysis is the correspondence between the Jacobian matrix (a representation of the feasibility boundary of the equations that describe the flow of power in the network) and the Laplacian matrix in spectral graph theory (a representation of the graph of the power grid). The reduced combinatorial problem is known as the network inhibition problem, for which we present a mixed integer linear programming formulation. Our experiments on benchmark power grids show that the reduced combinatorial model provides an accurate approximation, to enable vulnerability analyses of real-sized problems with more than 10,000 power lines.

  7. Becoming a Great Teacher of Reading: Achieving High Rapid Reading Gains with Powerful, Differentiated Strategies

    ERIC Educational Resources Information Center

    Carbo, Marie

    2007-01-01

    Literacy expert Marie Carbo pairs identifying each learner's unique reading style with a wide range of differentiated strategies to help all learners experience greater reading success. Using these research-based methods, both novice and experienced teachers can increase reading achievement with all learners, including those who are at-risk,…

  8. History Alive! Six Powerful Teaching Strategies. Manual for Engaging ALL Learners in the Diverse Classroom.

    ERIC Educational Resources Information Center

    Teachers' Curriculum Inst., Mountain View, CA.

    This book is used as a two-day workshop for teachers in how to use the "History Alive!" program. The three premises of the program include: (1) cooperative interaction; (2) multiple intelligences; and (3) the spiral curriculum. The strategies developed focus upon: (1) Interactive Slide Lectures; (2) Social Studies Skill Builders; (3) Experiential…

  9. School Power: Study Skill Strategies for Succeeding in School. Revised and Updated Edition.

    ERIC Educational Resources Information Center

    Schumm, Jeanne Shay

    This self-help book is aimed at middle school students who are learning to cope with different teachers' styles and rules, as well as learning how to follow a schedule. It provides tips, techniques, and strategies on how to read faster; take better notes in class; become a better writer; improve study skills; and ways to ask for help when needed.…

  10. The Power of ROFO Principle Together with Companywide Training in Executing Lean Production Strategy

    ERIC Educational Resources Information Center

    Goh, Ah Bee; Chakpitak, Nopasit; Sureephong, Pradorn

    2015-01-01

    This paper reports the findings of the case study conducted at Schaffner Thailand (ST) factory regarding the application of the ROFO principle coupled with companywide training on the execution of Lean Production (LP) strategy. The case study was motivated by 3 main objectives: 1) to examine the effectiveness of the ROFO principle and companywide…

  11. The Einstein Observatory catalog of IPC x ray sources. Volume 7E: Right ascension range 20h 00m to 23h 59m

    NASA Technical Reports Server (NTRS)

    Harris, D. E.; Forman, W.; Gioia, I. M.; Hale, J. A.; Harnden, F. R., Jr.; Jones, C.; Karakashian, T.; Maccacaro, T.; Mcsweeney, J. D.; Primini, F. A.

    1993-01-01

    The Einstein Observatory (HEAO-2, launched November 13, 1978) achieved radically improved sensitivity over previous x-ray missions through the use of focusing optics which simultaneously afforded greatly reduced background and produced true images. During its 2.5-yr mission, the Einstein X-Ray Telescope was pointed toward some 5,000 celestial targets, most of which were detected, and discovered several thousand additional 'serendipitous' sources in the observed fields. This catalog contains contour diagrams and source data, obtained with the imaging proportional counter in the 0.16 to 3.5 keV energy band, and describes methods for recovering upper limits for any sky position within the observed images. The main catalog consists of six volumes (numbered 2 through 7) of right ascension ordered pages, each containing data for one observation. Along with the primary documentation describing how the catalog was constructed, volume 1 contains a complete source list, results for merged fields, a reference system to published papers, and data useful for calculating upper limits and fluxes.

  12. The Einstein Observatory catalog of IPC x ray sources. Volume 4E: Right ascension range 08h 00m to 11h 59m

    NASA Technical Reports Server (NTRS)

    Harris, D. E.; Forman, W.; Gioia, I. M.; Hale, J. A.; Harnden, F. R., Jr.; Jones, C.; Karakashian, T.; Maccacaro, T.; Mcsweeney, J. D.; Primini, F. A.

    1993-01-01

    The Einstein Observatory (HEAO-2, launched November 13, 1978) achieved radically improved sensitivity over previous x-ray missions through the use of focusing optics which simultaneously afforded greatly reduced background and produced true images. During its 2.5-yr mission, the Einstein X-Ray Telescope was pointed toward some 5,000 celestial targets, most of which were detected, and discovered several thousand additional 'serendipitous' sources in the observed fields. This catalog contains contour diagrams and source data, obtained with the imaging proportional counter in the 0.16 to 3.5 keV energy band, and describes methods for recovering upper limits for any sky position within the observed images, The main catalog consists of six volumes (numbered 2 through 7) of right ascension ordered pages, each containing data for one observation. Along with the primary documentaion describing how the catalog was constructed, volume 1 contains a complete source list, results for merged fields, a reference system to published papers, and data useful for calculating upper limits and fluxes.

  13. The Einstein Observatory catalog of IPC x ray sources. Volume 3E: Right ascension range 04h 00m to 07h 59m

    NASA Technical Reports Server (NTRS)

    Harris, D. E.; Forman, W.; Gioia, I. M.; Hale, J. A.; Harnden, F. R., Jr.; Jones, C.; Karakashian, T.; Maccacaro, T.; Mcsweeney, J. D.; Primini, F. A.

    1993-01-01

    The Einstein Observatory (HEAO-2, launched November 13, 1978) achieved radically improved sensitivity over previous x-ray missions through the use of focusing optics which simultaneously afforded greatly reduced background and produced true images. During its 2.5-yr mission, the Einstein X-Ray Telescope was pointed toward some 5,000 celestial targets, most of which were detected, and discovered several thousand additional 'serendipitous' sources in the observed fields. This catalog contains contour diagrams and source data, obtained with the imaging proportional counter in the 0.16 to 3.5 keV energy band, and describes methods for recovering upper limits for any sky position within the observed images. The main catalog consists of six volumes (numbered 2 through 7) of right ascension ordered pages, each containing data for one observation. Along with the primary documentation describing how the catalog was constructed, volume 1 contains a complete source list, results for merged fields, a reference system to published papers and data useful for calculating upper limits and fluxes.

  14. The Einstein Observatory catalog of IPC x ray sources. Volume 5E: Right ascension range 12h 00m to 15h 59m

    NASA Technical Reports Server (NTRS)

    Harris, D. E.; Forman, W.; Gioia, I. M.; Hale, J. A.; Harnden, F. R., Jr.; Jones, C.; Karakashian, T.; Maccacaro, T.; Mcsweeney, J. D.; Primini, F. A.

    1993-01-01

    The Einstein Observatory (HEAO-2, launched November 13, 1978) achieved radically improved sensitivity over previous x-ray missions through the use of focusing optics, which simultaneously afforded greatly reduced background and produced true images. During its 2.5-yr mission, the Einstein X-Ray Telescope was pointed toward some 5,000 celestial targets, most of which were detected, and discovered several thousand additional 'serendipitous' sources in the observed fields. This catalog contains contour diagrams and source data, obtained with the imaging proportional counter in the 0.16 to 3.5 keV energy band, and describes methods for recovering upper limits for any sky position within the observed images. The main catalog consists of six volumes (numbered 2 through 7) of right ascension ordered pages, each containing data for one observation. Along with the primary documentation describing how the catalog was constructed, volume 1 contains a complete source list, results for merged fields, a reference system to published papers, and data useful for calculating upper limits and fluxes.

  15. The Einstein Observatory catalog of IPC x ray sources. Volume 6E: Right ascension range 16h 00m to 19h 59m

    NASA Technical Reports Server (NTRS)

    Harris, D. E.; Forman, W.; Gioia, I. M.; Hale, J. A.; Harnden, F. R., Jr.; Jones, C.; Karakashian, T.; Maccacaro, T.; Mcsweeney, J. D.; Primini, F. A.

    1993-01-01

    The Einstein Observatory (HEAO-2 launched November 13, 1978) achieved radically improved sensitivity over previous x-ray missions through the use of focusing optics, which simultaneously afforded greatly reduced background and produced true images. During its 2.5-yr mission, the Einstein X-Ray Telescope was pointed toward some 5,000 celestial targets, most of which were detected, and discovered several thousand additional 'serendipitous' sources in the observed fields. This catalog contains contour diagrams and source data, obtained with the imaging proportional counter in the 0.16 to 3.5 keV energy band, and describes methods for recovering upper limits for any sky position within the observed images. The main catalog consists of six volumes (numbered 2 through 7) of right ascension ordered pages, each containing data for one observation. Along with the primary documentation describing how the catalog was constructed, volume 1 contains a complete source list, results for merged fields, a reference system to published papers, and data useful for calculating upper limits and fluxes.

  16. The Einstein Observatory catalog of IPC x ray sources. Volume 2E: Right ascension range 00h 00m to 03h 59m

    NASA Technical Reports Server (NTRS)

    Harris, D. E.; Forman, W.; Gioia, I. M.; Hale, J. A.; Harnden, F. R., Jr.; Jones, C.; Karakashian, T.; Maccacaro, T.; Mcsweeney, J. D.; Primini, F. A.

    1993-01-01

    The Einstein Observatory (HEAO-2, launched November 13, 1978) achieved radically improved sensitivity over previous x-ray missions through the use of focusing optics which simultaneously afforded greatly reduced background and produced true images. During its 2.5-yr mission, the Einstein X-Ray Telescope was pointed toward some 5,000 celestial targets, most of which were detected, and discovered several thousand additional 'serendipitous' sources in the observed fields. This catalog contains contour diagrams and source data, obtained with the imaging proportional counter in the 0.16 to 3.5 keV energy band, and describes methods for recovering upper limits for any sky position within the observed images. The main catalog consists of six volumes (numbered 2 through 7) of right ascension ordered pages, each containing data for one observation. Along with the primary documentation describing how the catalog was constructed, volume 1 contains a complete source list, results for merged fields, a reference system to published papers and data useful for calculating upper limits and fluxes.

  17. Effects of Attentional Focusing Strategies on Muscular Power in Older Women.

    PubMed

    Makaruk, Hubert; Porter, Jared M; Dlugolecka, Barbara; Parnicka, Urszula; Makaruk, Beata

    2015-07-01

    The purpose of this study was to evaluate the effects of different foci of attention on parameters related to maximum muscular power in older women. Using a counterbalanced within-participant design, 23 physically active young-old women (age 59-69) completed a maximum effort cycle ergometer test following three types of verbal instructions. The external instruction (EXF) was designed to focus attention on moving the pedals as fast as possible, internal instruction (INF) directed attention toward moving the legs as fast as possible, and a control condition (CON) was created in which participants were instructed to perform the task to the best of their abilities. Results indicated that the EXF and CON conditions resulted in greater muscular power compared with the INF condition. Results also indicated that directing attention internally hindered muscular power performance in older women, which is consistent with the predictions of the constrained action hypothesis. PMID:24956607

  18. Evaluation of operational control strategies applicable to solar chimney power plants

    SciTech Connect

    Bernardes, Marco Aurelio dos Santos; von Backstroem, Theodor W.

    2010-02-15

    Numerical simulations are carried out to study the performance of two schemes of power output control applicable to solar chimney power plants. Either the volume flow or the turbine pressure drop is used as independent control variable. Values found in the literature for the optimum ratio of turbine pressure drop to pressure potential vary between 2/3 and 0.97. It is shown that the optimum ratio is not constant during the whole day and it is dependent of the heat transfer coefficients applied to the collector. This study is a contribution towards understanding solar chimney power plant performance and control and may be useful in the design of solar chimney turbines. (author)

  19. Systems and methods for providing power to a load based upon a control strategy

    DOEpatents

    Perisic, Milun; Kajouke, Lateef A; Ransom, Ray M

    2013-12-24

    Systems and methods are provided for an electrical system. The electrical system includes a load, an interface configured to receive a voltage from a voltage source, and a controller configured to receive the voltage from the voltage source through the interface and to provide a voltage and current to the load. Wherein, when the controller is in a constant voltage mode, the controller provides a constant voltage to the load, when the controller is in a constant current mode, the controller provides a constant current to the load, and when the controller is in a constant power mode, the controller provides a constant power to the load.

  20. Delivery of Terrigenous Material to Submarine Fans: Biological Evidence of Local, Staged, and Possibly Full Canyon Sediment Transport Down the Ascension-Monterey Canyon System Off Central California, USA

    NASA Astrophysics Data System (ADS)

    McGann, M.

    2014-12-01

    Submarine canyons are instrumental in transporting sediment from coastal regions to deep-sea fans. Mean grain size, distribution, and sorting have been used to characterize these deposits, but they provide little information on where sediment transport was initiated or the delivery processes involved. Fortunately, the entrained biological constituents have unique environmental signatures that are more precise proxies for source areas than are mineral grains alone. They may identify a single biofacies deposit (SBD) resulting from local sediment transport such as storm waves, peak river discharge, breaking of internal waves, canyon wall sloughing, or hemipelagic deposition, or a displaced, multiple biofacies deposit (MBD) containing several biofacies where sediment is transported from one biofacies to another, is caught behind a slump that acts as a dam, remains there long enough for the local fauna to become established, and then this combined assemblage is transported further downslope when the dam breaks. Multiple episodes of this "staged" storage-and-release process occur sequentially so as to move the sediment progressively down the canyon. Rarely, exceptionally large triggers such as earthquakes, intense storm disturbances, and catastrophic failure of canyon walls result in full canyon flushing events, entraining numerous biofacies during a single rapid descent. These events can be differentiated in recent deposits by the presence of living specimens representing distinct biofacies or in historic records by dating individual biofacies within a turbidite. A 19,000 year record from the Ascension-Monterey Canyon system (core S3-15G, 36°23.53'N, 123°20.52'W; 3491 m) captured hemipelagic mud interspersed with turbiditic sand and silt transported to lower bathyal depths. The relative abundance of displaced benthic foraminifera was found to correlate positively with grain size (75% in cross-bedded turbiditic sands, 39% in laminated turbiditic sands, and 15% in

  1. The Power of Teacher Teams: With Cases, Analyses, and Strategies for Success

    ERIC Educational Resources Information Center

    Troen, Vivian; Boles, Katherine C.

    2012-01-01

    While most educators believe working in teams is valuable, not all team efforts lead to instructional improvement. Through richly detailed case studies, "The Power of Teacher Teams" demonstrates how schools can transform their teams into more effective learning communities that foster teacher leadership. The benefits of successful teacher teams…

  2. Synergistic mercury removal by conventional pollutant control strategies for coal-fired power plants in China.

    PubMed

    Wang, Shuxiao; Zhang, Lei; Wu, Ye; Ancora, Maria Pia; Zhao, Yu; Hao, Jiming

    2010-06-01

    China's 11th 5-yr plan has regulated total sulfur dioxide (SO2) emissions by installing flue gas desulfurization (FGD) devices and shutting down small thermal power units. These control measures will not only significantly reduce the emission of conventional pollutants but also benefit the reduction of mercury emissions from coal-fired power plants. This paper uses the emission factor method to estimate the efficiencies of these measures on mercury emission abatement. From 2005 to 2010, coal consumption in power plants will increase by 59%; however, the mercury emission will only rise from 141 to 155 t, with an increase of 10%. The average emission rate of mercury from coal burning will decrease from 126 mg Hg/t of coal to 87 mg Hg/t of coal. The effects of the three desulfurization measures were assessed and show that wet FGD will play an important role in mercury removal. Mercury emissions in 2015 and 2020 are also projected under different policy scenarios. Under the most probable scenario, the total mercury emission in coal-fired power plants in China will decrease to 130 t by 2020, which will benefit from the rapid installation of fabric filters and selective catalytic reduction. PMID:20564998

  3. Enhancing Specific Energy and Power in Asymmetric Supercapacitors - A Synergetic Strategy based on the Use of Redox Additive Electrolytes.

    PubMed

    Singh, Arvinder; Chandra, Amreesh

    2016-01-01

    The strategy of using redox additive electrolyte in combination with multiwall carbon nanotubes/metal oxide composites leads to a substantial improvements in the specific energy and power of asymmetric supercapacitors (ASCs). When the pure electrolyte is optimally modified with a redox additive viz., KI, ~105% increase in the specific energy is obtained with good cyclic stability over 3,000 charge-discharge cycles and ~14.7% capacitance fade. This increase is a direct consequence of the iodine/iodide redox pairs that strongly modifies the faradaic and non-faradaic type reactions occurring on the surface of the electrodes. Contrary to what is shown in few earlier reports, it is established that indiscriminate increase in the concentration of redox additives will leads to performance loss. Suitable explanations are given based on theoretical laws. The specific energy or power values being reported in the fabricated ASCs are comparable or higher than those reported in ASCs based on toxic acetonitrile or expensive ionic liquids. The paper shows that the use of redox additive is economically favorable strategy for obtaining cost effective and environmentally friendly ASCs. PMID:27184260

  4. Enhancing Specific Energy and Power in Asymmetric Supercapacitors - A Synergetic Strategy based on the Use of Redox Additive Electrolytes

    PubMed Central

    Singh, Arvinder; Chandra, Amreesh

    2016-01-01

    The strategy of using redox additive electrolyte in combination with multiwall carbon nanotubes/metal oxide composites leads to a substantial improvements in the specific energy and power of asymmetric supercapacitors (ASCs). When the pure electrolyte is optimally modified with a redox additive viz., KI, ~105% increase in the specific energy is obtained with good cyclic stability over 3,000 charge-discharge cycles and ~14.7% capacitance fade. This increase is a direct consequence of the iodine/iodide redox pairs that strongly modifies the faradaic and non-faradaic type reactions occurring on the surface of the electrodes. Contrary to what is shown in few earlier reports, it is established that indiscriminate increase in the concentration of redox additives will leads to performance loss. Suitable explanations are given based on theoretical laws. The specific energy or power values being reported in the fabricated ASCs are comparable or higher than those reported in ASCs based on toxic acetonitrile or expensive ionic liquids. The paper shows that the use of redox additive is economically favorable strategy for obtaining cost effective and environmentally friendly ASCs. PMID:27184260

  5. Enhancing Specific Energy and Power in Asymmetric Supercapacitors - A Synergetic Strategy based on the Use of Redox Additive Electrolytes

    NASA Astrophysics Data System (ADS)

    Singh, Arvinder; Chandra, Amreesh

    2016-05-01

    The strategy of using redox additive electrolyte in combination with multiwall carbon nanotubes/metal oxide composites leads to a substantial improvements in the specific energy and power of asymmetric supercapacitors (ASCs). When the pure electrolyte is optimally modified with a redox additive viz., KI, ~105% increase in the specific energy is obtained with good cyclic stability over 3,000 charge-discharge cycles and ~14.7% capacitance fade. This increase is a direct consequence of the iodine/iodide redox pairs that strongly modifies the faradaic and non-faradaic type reactions occurring on the surface of the electrodes. Contrary to what is shown in few earlier reports, it is established that indiscriminate increase in the concentration of redox additives will leads to performance loss. Suitable explanations are given based on theoretical laws. The specific energy or power values being reported in the fabricated ASCs are comparable or higher than those reported in ASCs based on toxic acetonitrile or expensive ionic liquids. The paper shows that the use of redox additive is economically favorable strategy for obtaining cost effective and environmentally friendly ASCs.

  6. Settler colonial power and the American Indian sovereignty movement: forms of domination, strategies of transformation.

    PubMed

    Steinman, Erich

    2012-01-01

    The article extends the multi-institutional model of power and change through an analysis of the American Indian Sovereignty Movement. Drawing upon cultural models of the state, and articulating institutionalist conceptions of political opportunities and resources, the analysis demonstrates that this framework can be applied to challenges addressing the state as well as nonstate fields. The rational-legal diminishment of tribal rights, bureaucratic paternalism, commonsense views of tribes as racial/ethnic minorities, and the binary construction of American and Indian as oppositional identities diminished the appeal of "contentious" political action. Instead, to establish tribes' status as sovereign nations, tribal leaders aggressively enacted infrastructural power, transposed favorable legal rulings across social fields to legitimize sovereignty discourses, and promoted a pragmatic coexistence with state and local governments. Identifying the United States as a settler colonial society, the study suggests that a decolonizing framework is more apt than racial/ethnicity approaches in conceptualizing the struggle of American Indians. PMID:22594118

  7. An effective control strategy to maximize power extraction from wind turbines

    NASA Astrophysics Data System (ADS)

    Mouhadjer, Samir; Benmedjahed, Miloud; Neçaïbia, Ammar

    2016-07-01

    Among the various identifiable renewable energies sources, one holds the attention in this study for its important potential in the world; it's about wind energy. Our objective in this present work is to contribute a share to the research solution to the problems of coupling between this energy source and the load; it's about the transfer of the maximum power to the latter which often suffers from a bad matching. In order to maximize the wind power extraction, this work describes design of a PWM rectifier controller for wind turbines. Generic PWM rectifier is used and PICl6F876 Microcontroller is proposed. The goal of the controller is to keep operating point as close to the maximum efficiency as possible.

  8. Photoenergy storage and power amplification strategy in membrane-less photoelectrochemical biofuel cells.

    PubMed

    Yu, You; Xu, Miao; Dong, Shaojun

    2016-05-10

    The photoelectrochemical biofuel cell (PBFC) has drawn great attention because of its potential in the conversion of both photoenergy and chemical energy from biomass into electricity. Herein, we proposed a novel integrated PBFC by insetting a third electrode with high efficiency energy storage and release between the bioelectrode and the photoelectrode, resulting in a higher power output than that of the original PBFC. PMID:27117777

  9. Control Strategies for Smoothing of Output Power of Wind Energy Conversion Systems

    NASA Astrophysics Data System (ADS)

    Pratap, Alok; Urasaki, Naomitsu; Senju, Tomonobu

    2013-10-01

    This article presents a control method for output power smoothing of a wind energy conversion system (WECS) with a permanent magnet synchronous generator (PMSG) using the inertia of wind turbine and the pitch control. The WECS used in this article adopts an AC-DC-AC converter system. The generator-side converter controls the torque of the PMSG, while the grid-side inverter controls the DC-link and grid voltages. For the generator-side converter, the torque command is determined by using the fuzzy logic. The inputs of the fuzzy logic are the operating point of the rotational speed of the PMSG and the difference between the wind turbine torque and the generator torque. By means of the proposed method, the generator torque is smoothed, and the kinetic energy stored by the inertia of the wind turbine can be utilized to smooth the output power fluctuations of the PMSG. In addition, the wind turbines shaft stress is mitigated compared to a conventional maximum power point tracking control. Effectiveness of the proposed method is verified by the numerical simulations.

  10. Designing Effective Persuasive Systems Utilizing the Power of Entanglement: Communication Channel, Strategy and Affect

    NASA Astrophysics Data System (ADS)

    Li, Haiqing; Chatterjee, Samir

    With rapid advances in information and communication technology, computer-mediated communication (CMC) technologies are utilizing multiple IT platforms such as email, websites, cell-phones/PDAs, social networking sites, and gaming environments. However, no studies have compared the effectiveness of a persuasive system using such alternative channels and various persuasive techniques. Moreover, how affective computing impacts the effectiveness of persuasive systems is not clear. This study proposes (1) persuasive technology channels in combination with persuasive strategies will have different persuasive effectiveness; (2) Adding positive emotion to a message that leads to a better overall user experience could increase persuasive effectiveness. The affective computing or emotion information was added to the experiment using emoticons. The initial results of a pilot study show that computer-mediated communication channels along with various persuasive strategies can affect the persuasive effectiveness to varying degrees. These results also shows that adding a positive emoticon to a message leads to a better user experience which increases the overall persuasive effectiveness of a system.

  11. The Northeastern United States Energy-Water Nexus: Climate Change Impacts and Alternative Water Management Strategies for the Power Sector

    NASA Astrophysics Data System (ADS)

    Miara, A.; Macknick, J.; Vorosmarty, C. J.; Cohen, S. M.; Rosenzweig, B.

    2014-12-01

    The Northeastern United States (NE) relies heavily on thermoelectric power plants (90% of total capacity) to provide electricity to more than 70 million people. This region's power plants require consistent, large volumes of water at sufficiently cold temperatures to generate electricity efficiently, and withdraw approximately 10.5 trillion gallons of water annually. Previous findings indicate that assessments of future electricity pathways must account for water availability, water temperature and the changing climate, as changes in these conditions may limit operational efficiency in the future. To account for such electric system vulnerabilities, we have created a link between an electricity system capacity expansion model (ReEDS) and a hydrologic model that is coupled to a power plant simulation model (FrAMES-TP2M) that allows for a new approach to analyze electricity system development, performance, and environmental impacts. Together, these coupled tools allow us to estimate electricity development and operations in the context of a changing climate and impacts on the seasonal spatial and temporal variability of water resources, downstream thermal effluents that cause plant-to-plant interferences and harm aquatic habitat, economic costs of water conservation methods and associated carbon emissions. In this study, we test and compare a business-as-usual strategy with three alternative water management scenarios that include changes in cooling technologies and water sources utilized for the years 2014-2050. Results of these experiments can provide useful insight into the feasibility of the electricity expansion scenarios in terms of associated water use and thermal impacts, carbon emissions, the cost of generating electricity, and also highlight the importance of accounting for water resources in future power sector planning and performance assessments.

  12. Nash equilibrium strategy in the deregulated power industry and comparing its lost welfare with Iran wholesale electricity market

    NASA Astrophysics Data System (ADS)

    Mousavi, Seyed Hosein; Nazemi, Ali; Hafezalkotob, Ashkan

    2016-07-01

    With the increasing use of different types of auctions in market designing, modeling of participants' behaviors to evaluate the market structure is one of the main discussions in the studies related to the deregulated power industries. In this article, we apply an approach of the optimal bidding behavior to the Iran wholesale electricity market as a restructured electric power industry and model how the participants of the market bid in the spot electricity market. The problem is formulated analytically using the Nash equilibrium concept composed of large numbers of players having discrete and very large strategy spaces. Then, we compute and draw supply curve of the competitive market in which all generators' proposed prices are equal to their marginal costs and supply curve of the real market in which the pricing mechanism is pay-as-bid. We finally calculate the lost welfare or inefficiency of the Nash equilibrium and the real market by comparing their supply curves with the competitive curve. We examine 3 cases on November 24 (2 cases) and July 24 (1 case), 2012. It is observed that in the Nash equilibrium on November 24 and demand of 23,487 MW, there are 212 allowed plants for the first case (plants are allowed to choose any quantity of generation except one of them that should be equal to maximum Power) and the economic efficiency or social welfare of Nash equilibrium is 2.77 times as much as the real market. In addition, there are 184 allowed plants for the second case (plants should offer their maximum power with different prices) and the efficiency or social welfare of Nash equilibrium is 3.6 times as much as the real market. On July 24 and demand of 42,421 MW, all 370 plants should generate maximum energy due to the high electricity demand that the economic efficiency or social welfare of the Nash equilibrium is about 2 times as much as the real market.

  13. Monitored Natural Attenuation as a Remediation Strategy for Nuclear Power Plant Applications

    NASA Astrophysics Data System (ADS)

    Kim, K.; Bushart, S.

    2009-12-01

    A NRC Information Notice (IN 2006-13) was produced to inform holders of nuclear operating licenses “of the occurrence of radioactive contamination of ground water at multiple facilities due to undetected leakage from facility structures, systems, or components (SSCs) that contain or transport radioactive fluids” so that they could consider actions, as appropriate, to avoid similar problems. To reinforce their commitment to environmental stewardship the nuclear energy industry has committed to improving management of situations that have the potential to lead to the inadvertent release of radioactive fluids. This Industry Groundwater Protection Initiative, finalized in June 2007 as [NEI 07-07], calls for implementation and improvement of on-site groundwater monitoring programs and enhanced communications with stakeholders and regulators about situations related to inadvertent releases. EPRI developed its Groundwater Protection Program to provide the nuclear energy industry with the technical support needed to implement the Industry Groundwater Initiative. An objective of the EPRI Groundwater Protection Program is to provide the nuclear industry with technically sound guidance for implementing and enhancing on-site groundwater monitoring programs. EPRI, in collaboration with the EPRI Groundwater Protection Committee of utility members, developed the EPRI Groundwater Protection Guidelines for Nuclear Power Plants (EPRI Report 1015118, November 2007), which provides site-specific guidance for implementing a technically sound groundwater monitoring program. The guidance applies a graded approach for nuclear plants to tailor a technically effective and cost efficient groundwater monitoring program to the site’s hydrogeology and risk for groundwater contamination. As part of the Groundwater Protection Program, EPRI is also investigating innovative remediation technologies for addressing low-level radioactive contamination in soils and groundwater at nuclear power

  14. Coping with carbon: a near-term strategy to limit carbon dioxide emissions from power stations.

    PubMed

    Breeze, Paul

    2008-11-13

    Burning coal to generate electricity is one of the key sources of atmospheric carbon dioxide emissions; so, targeting coal-fired power plants offers one of the easiest ways of reducing global carbon emissions. Given that the world's largest economies all rely heavily on coal for electricity production, eliminating coal combustion is not an option. Indeed, coal consumption is likely to increase over the next 20-30 years. However, the introduction of more efficient steam cycles will improve the emission performance of these plants over the short term. To achieve a reduction in carbon emissions from coal-fired plant, however, it will be necessary to develop and introduce carbon capture and sequestration technologies. Given adequate investment, these technologies should be capable of commercial development by ca 2020. PMID:18757277

  15. Investigation of neural-net based control strategies for improved power system dynamic performance

    SciTech Connect

    Sobajic, D.J.

    1995-12-31

    The ability to accurately predict the behavior of a dynamic system is of essential importance in monitoring and control of complex processes. In this regard recent advances in neural-net base system identification represent a significant step toward development and design of a new generation of control tools for increased system performance and reliability. The enabling functionality is the one of accurate representation of a model of a nonlinear and nonstationary dynamic system. This functionality provides valuable new opportunities including: (1) The ability to predict future system behavior on the basis of actual system observations, (2) On-line evaluation and display of system performance and design of early warning systems, and (3) Controller optimization for improved system performance. In this presentation, we discuss the issues involved in definition and design of learning control systems and their impact on power system control. Several numerical examples are provided for illustrative purpose.

  16. Power politics: National energy strategies of the nuclear newly independent states of Armenia, Lithuania and Ukraine

    NASA Astrophysics Data System (ADS)

    Sabonis-Chafee, Theresa Marie

    The successor states of Armenia, Lithuania and Ukraine arrived at independence facing extraordinary challenges in their energy sectors. Each state was a net importer, heavily dependent on cheap energy supplies, mostly from Russia. Each state also inherited a nuclear power complex over which it had not previously exercised full control. In the time period 1991--1996, each state attempted to impose coherence on the energy sector, selecting a new course for the pieces it had inherited from a much larger, highly integrated energy structure. Each state attempted to craft national energy policies in the midst of severe supply shocks and price shocks. Each state developed institutions to govern its nuclear power sector. The states' challenges were made even greater by the fact that they had few political or economic structures necessary for energy management, and sought to create those structures at the same time. This dissertation is a systematic, non-quantitative examination of how each state's energy policies developed during the 1991--1996 time period. The theoretical premise of the analysis (drawn from Statist realism) is that systemic variables---regional climate and energy vulnerability---provide the best explanations for the resulting energy policy decisions. The dependent variable is defined as creation and reform of energy institutions. The independent variables include domestic climate, regional climate, energy vulnerability and transnational assistance. All three states adopted rhetoric and legislation declaring energy a strategic sector. The evidence suggests that two of the states, Armenia and Lithuania, which faced tense regional climates and high levels of energy vulnerability, succeeded in actually treating energy strategically, approaching energy as a matter of national security or "high politics." The third state, Ukraine, failed to do so. The evidence presented suggests that the systemic variables (regional climate and energy vulnerability) provided a

  17. In-vessel melt retention as a severe accident management strategy for the Loviisa Nuclear Power Plant

    SciTech Connect

    Kymaelaeinen, O.; Tuomisto, H.; Theofanous, T.G.

    1997-02-01

    The concept of lower head coolability and in-vessel retention of corium has been approved as a basic element of the severe accident management strategy for IVO`s Loviisa Plant (VVER-440) in Finland. The selected approach takes advantage of the unique features of the plant such as low power density, reactor pressure vessel without penetrations at the bottom and ice-condenser containment which ensures flooded cavity in all risk significant sequences. The thermal analyses, which are supported by experimental program, demonstrate that in Loviisa the molten corium on the lower head of the reactor vessel is coolable externally with wide margins. This paper summarizes the approach and the plant modifications being implemented. During the approval process some technical concerns were raised, particularly with regard to thermal loadings caused by contact of cool cavity water and hot corium with the reactor vessel. Resolution of these concerns is also discussed.

  18. A hybrid interval-parameter fuzzy robust programming method and its application to filter management strategy in fluid power systems

    NASA Astrophysics Data System (ADS)

    Nie, S. L.; Ji, H.; Huang, Y. Q.; Li, Y. P.; Huang, G. H.

    2014-01-01

    An interval-parameter fuzzy robust programming (IFRP) method is developed for the assessment of filter allocation and replacement strategies in a fluid power system (FPS) under uncertainty. The developed IFRP can effectively handle the uncertainties expressed as fuzzy sets, interval values, and their combinations, which exist in contaminant ingression/generation of the system and contaminant-holding capacity of filter without making assumptions on their probabilistic distributions. The fuzzy decision space can be delimited into a more robust one with the uncertainties being specified through dimensional enlargement of the original fuzzy constraints, leading to enhanced robustness for the optimization process. Results indicate that the developed IFRP can not only help decision-maker to identify optimal filter allocation and replacement strategies to control the contamination level of FPS with a minimized system-cost and system-failure risk under multiple uncertainties, but also mitigate uncertainties through abating interval widths of the replacement periods and service life under different contamination ingression/generation rates.

  19. Quantifying the efficiency and equity implications of power plant air pollution control strategies in the United States

    SciTech Connect

    Levy, J.I.; Wilson, A.M.; Zwack, L.M.

    2007-05-15

    We modeled the public health benefits and the change in the spatial inequality of health risk for a number of hypothetical control scenarios for power plants in the United States to determine optimal control strategies. We simulated various ways by which emission reductions of sulfur dioxide (SO{sub 2}), nitrogen oxides, and fine particulate matter (PM2.5) could be distributed to reach national emissions caps. We applied a source-receptor matrix to determine the PM2.5 concentration changes associated with each control scenario and estimated the mortality reductions. We estimated changes in the spatial inequality of health risk using the Atkinson index and other indicators, following previously derived axioms for measuring health risk inequality. In our baseline model, benefits ranged from 17,000-21,000 fewer premature deaths per year across control scenarios. Scenarios with greater health benefits also tended to have greater reductions in the spatial inequality of health risk, as many sources with high health benefits per unit emissions of SO{sub 2} were in areas with high background PM2.5 concentrations. Sensitivity analyses indicated that conclusions were generally robust to the choice of indicator and other model specifications. Our analysis demonstrates an approach for formally quantifying both the magnitude and spatial distribution of health benefits of pollution control strategies, allowing for joint consideration of efficiency and equity.

  20. Two-trait-locus linkage analysis: A powerful strategy for mapping complex genetic traits

    SciTech Connect

    Schork, N.J.; Boehnke, M. ); Terwilliger, J.D.; Ott, J. )

    1993-11-01

    Nearly all diseases mapped to date follow clear Mendelian, single-locus segregation patterns. In contrast, many common familial diseases such as diabetes, psoriasis, several forms of cancer, and schizophrenia are familial and appear to have a genetic component but do not exhibit simple Mendelian transmission. More complex models are required to explain the genetics of these important diseases. In this paper, the authors explore two-trait-locus, two-marker-locus linkage analysis in which two trait loci are mapped simultaneously to separate genetic markers. The authors compare the utility of this approach to standard one-trait-locus, one-marker-locus linkage analysis with and without allowance for heterogeneity. The authors also compare the utility of the two-trait-locus, two-marker-locus analysis to two-trait-locus, one-marker-locus linkage analysis. For common diseases, pedigrees are often bilineal, with disease genes entering via two or more unrelated pedigree members. Since such pedigrees often are avoided in linkage studies, the authors also investigate the relative information content of unilineal and bilineal pedigrees. For the dominant-or-recessive and threshold models that the authors consider, the authors find that two-trait-locus, two-marker-locus linkage analysis can provide substantially more linkage information, as measured by expected maximum lod score, than standard one-trait-locus, one-marker-locus methods, even allowing for heterogeneity, while, for a dominant-or-dominant generating model, one-locus models that allow for heterogeneity extract essentially as much information as the two-trait-locus methods. For these three models, the authors also find that bilineal pedigrees provide sufficient linkage information to warrant their inclusion in such studies. The authors discuss strategies for assessing the significance of the two linkages assumed in two-trait-locus, two-marker-locus models. 37 refs., 1 fig., 4 tabs.

  1. Xenon Acquisition Strategies for High-Power Electric Propulsion NASA Missions

    NASA Technical Reports Server (NTRS)

    Herman, Daniel A.; Unfried, Kenneth G.

    2015-01-01

    Solar electric propulsion (SEP) has been used for station-keeping of geostationary communications satellites since the 1980s. Solar electric propulsion has also benefitted from success on NASA Science Missions such as Deep Space One and Dawn. The xenon propellant loads for these applications have been in the 100s of kilograms range. Recent studies performed for NASA's Human Exploration and Operations Mission Directorate (HEOMD) have demonstrated that SEP is critically enabling for both near-term and future exploration architectures. The high payoff for both human and science exploration missions and technology investment from NASA's Space Technology Mission Directorate (STMD) are providing the necessary convergence and impetus for a 30-kilowatt-class SEP mission. Multiple 30-50- kilowatt Solar Electric Propulsion Technology Demonstration Mission (SEP TDM) concepts have been developed based on the maturing electric propulsion and solar array technologies by STMD with recent efforts focusing on an Asteroid Redirect Robotic Mission (ARRM). Xenon is the optimal propellant for the existing state-of-the-art electric propulsion systems considering efficiency, storability, and contamination potential. NASA mission concepts developed and those proposed by contracted efforts for the 30-kilowatt-class demonstration have a range of xenon propellant loads from 100s of kilograms up to 10,000 kilograms. This paper examines the status of the xenon industry worldwide, including historical xenon supply and pricing. The paper will provide updated information on the xenon market relative to previous papers that discussed xenon production relative to NASA mission needs. The paper will discuss the various approaches for acquiring on the order of 10 metric tons of xenon propellant to support potential near-term NASA missions. Finally, the paper will discuss acquisitions strategies for larger NASA missions requiring 100s of metric tons of xenon will be discussed.

  2. Theoretical proof of edge search strategy applied to power plant start-up scheduling.

    PubMed

    Kamiya, A; Kawai, K; Ono, I; Kobayashi, S

    2002-01-01

    Power plant start-up scheduling is aimed at minimizing the start-up time while limiting maximum turbine rotor stresses. This scheduling problem is highly nonlinear and has a number of local optima. In our previous research, we proposed an efficient search model: genetic algorithms (GAs) with enforcement operation to focus the search along the edge of the feasible space where the optimal schedule is supposed to stay. Based on a nonlinear dynamic simulation and a linear inverse calculation with the iteration method, the enforcement operation is applied to move schedules generated by GA toward the edge. We prove that the optimal schedule lies on the edge, ensuring that searching along the edge instead of the entire space can improve the search efficiency significantly without missing the optimum. Furthermore, we provide a theoretical setting equation for the inverse enforcement gains of the linear inverse calculation, intended to move schedules closer to the edge at each iteration of the enforcement operation. The theoretical setting equation is verified and discussed with the test results. We propose the theoretical setting equation with the test results as a guideline for the use of our proposed search model: GA with enforcement operation. PMID:18238130

  3. Hybrid Electric Power Train and Control Strategies Automotive Technology Education (GATE) Program

    SciTech Connect

    Andrew Frank

    2006-05-31

    Plug-in hybrid electric vehicles (PHEV) offer societal benefits through their ability to displace the use of petroleum fuels. Petroleum fuels represent a polluting and politically destabilizing energy carrier. PHEV technologies can move transportation away from petroleum fuel sources by enabling domestically generated electricity and liquids bio-fuels to serve as a carrier for transportation energy. Additionally, the All-Electric-Range (AER) offered by PHEVs can significantly reduce demand for expensive and polluting liquid fuels. The GATE funding received during the 1998 through 2004 funding cycle by the UC Davis Hybrid Electric Vehicle Center (HEVC) was used to advance and train researchers in PHEV technologies. GATE funding was used to construct a rigorous PHEV curriculum, provide financial support for HEVC researchers, and provide material support for research efforts. A rigorous curriculum was developed through the UC Davis Mechanical and Aeronautical Engineering Department to train HEVC researchers. Students' research benefited from this course work by advancing the graduate student researchers' understanding of key PHEV design considerations. GATE support assisted HEVC researchers in authoring technical articles and producing patents. By supporting HEVC researchers multiple Master's theses were written as well as journal articles and publications. The topics from these publications include Continuously Variable Transmission control strategies and PHEV cross platform controls software development. The GATE funding has been well used to advance PHEV systems. The UC Davis Hybrid Electric Vehicle Center is greatly appreciative for the opportunities GATE funding provided. The goals and objectives for the HEVC GATE funding were to nourish engineering research in PHEV technologies. The funding supplied equipment needed to allow researchers to investigate PHEV design sensitivities and to further optimize system components. Over a dozen PHEV researchers benefited

  4. Hydro-economic performances of streamflow withdrawal strategies: the case of small run-of-river power plants

    NASA Astrophysics Data System (ADS)

    Basso, Stefano; Lazzaro, Gianluca; Schirmer, Mario; Botter, Gianluca

    2014-05-01

    River flows withdrawals to supply small run-of-river hydropower plants have been increasing significantly in recent years - particularly in the Alpine area - as a consequence of public incentives aimed at enhancing energy production from renewable sources. This growth further raised the anthropic pressure in areas traditionally characterized by an intense exploitation of water resources, thereby triggering social conflicts among local communities, hydropower investors and public authorities. This brought to the attention of scientists and population the urgency for novel and quantitative tools for assessing the hydrologic impact of these type of plants, and trading between economic interests and ecologic concerns. In this contribution we propose an analytical framework that allows for the estimate of the streamflow availability for hydropower production and the selection of the run-of-river plant capacity, as well as the assessment of the related profitability and environmental impacts. The method highlights the key role of the streamflow variability in the design process, by showing the significance control of the coefficient of variation of daily flows on the duration of the optimal capacity of small run-of-river plants. Moreover, the analysis evidences a gap between energy and economic optimizations, which may result in the under-exploitation of the available hydropower potential at large scales. The disturbances to the natural flow regime produced between the intake and the outflow of run-of-river power plants are also estimated within the proposed framework. The altered hydrologic regime, described through the probability distribution and the correlation function of streamflows, is analytically expressed as a function of the natural regime for different management strategies. The deviations from pristine conditions of a set of hydrologic statistics are used, jointly with an economic index, to compare environmental and economic outcomes of alternative plant

  5. Real-time combined heat and power operational strategy using a hierarchical optimization algorithm

    SciTech Connect

    Yun, K.; Cho, H.; Luck, R.; Mago, P. J.

    2011-06-01

    Existing attempts to optimize the operation of combined heat and power (CHP) systems for building applications have two major limitations: the electrical and thermal loads are obtained from historical weather profiles; and the CHP system models ignore transient responses by using constant equipment efficiencies. This article considers the transient response of a building combined with a hierarchical CHP optimal control algorithm to obtain a real-time integrated system that uses the most recent weather and electric load information. This is accomplished by running concurrent simulations of two transient building models. The first transient building model uses current as well as forecast input information to obtain short-term predictions of the thermal and electric building loads. The predictions are then used by an optimization algorithm (i.e. a hierarchical controller that decides the amount of fuel and of electrical energy to be allocated at the current time step). In a simulation, the actual physical building is not available and, hence, to simulate a real-time environment, a second, building model with similar but not identical input loads are used to represent the actual building. A state-variable feedback loop is completed at the beginning of each time step by copying (i.e. measuring, the state variable from the actual building and restarting the predictive model using these ‘measured’ values as initial conditions). The simulation environment presented in this article features non-linear effects such as the dependence of the heat exchanger effectiveness on their operating conditions. Finally, the results indicate that the CHP engine operation dictated by the proposed hierarchical controller with uncertain weather conditions has the potential to yield significant savings when compared with conventional systems using current values of electricity and fuel prices.

  6. Strategies to Bulk Half-Heusler Nanocomposites with Simultaneously Enhanced Power Factor and Reduced Thermal Conductivity

    NASA Astrophysics Data System (ADS)

    Poudeu, Pierre Ferdinand

    2011-03-01

    Among promising thermoelectric materials for power generation, half-Heusler (HH) phases with general compositions TNiSn and TCoSb (T = Ti, Zr, Hf) have attracted tremendous attention not only because they involve abundant and environmentally friendly elements, but also due to their combination of large Seebeck coefficients with moderately low electrical resistivities. However, the ability to synthesize HH based materials with decent figures of merit (ZT> 1) hasbeenjeopardizedbytheirverylargethermalconductivities . StrategiestoreducethethermalconductivityofHHphasesfocusingonmassfluctuationphononscatteringviasolidsolutionalloyingorphononscatteringatgrainboundariesandinterfacesinHHphaseswithembeddedpre - synthesizednanoparticleshavefailedtogeneratematerialswithhighfiguresofmeritduetosimultaneousreductionsinthepowerfactor . Here , weintroduceinnovativeapproachestorevolutionaryincreasesinthefigureofmeritofHHbasedmaterialsthroughsimultaneouslargeenhancementofthepowerfactoranddrasticreductioninthethermalconductivity . Ourstrategyisfocusedonatomic - scalestructuralengineeringoftheHHmatrixthroughtheconfinementoffull - Heusler (FH) inclusionphasesonthelatticeconstantlength - scale . Emphasiswillbeplacedonthen - typeZr 0.25 Hf 0.75 Ni 1+x Sn 1-y Pn y andTi 0.5 Zr 0.5 Ni 1+x Sn 1-y Pn y aswellasthep - typeTi 0.5 Zr 0.5 Co 1+x Pn 1-y Sn y , (Pn = Sb, Bi) nanocomposites. We will discuss the underlying mechanism for the formation of half-Heusler/full-Heusler (HH/FH) nanocomposites with coherent matrix/inclusion interfaces. The role of synthetic and processing methods; and size, dispersion and mole fraction of the FH inclusions on the thermoelectric performance of bulk HH/FH nanocomposites will be assessed by combining transmission electron microscopy studies with thermal and electronic charge transport data. Financial support from DARPA contract # HR 0011-08-1-0084 is greatly acknowledged. This work made use of the laser flash diffusivity apparatus (Netzsch-LFA457) purchased with

  7. Waste Management Strategy for Dismantling Waste to Reduce Costs for Power Plant Decommissioning - 13543

    SciTech Connect

    Larsson, Arne; Lidar, Per; Bergh, Niklas; Hedin, Gunnar

    2013-07-01

    Decommissioning of nuclear power plants generates large volumes of radioactive or potentially radioactive waste. The proper management of the dismantling waste plays an important role for the time needed for the dismantling phase and thus is critical to the decommissioning cost. An efficient and thorough process for inventorying, characterization and categorization of the waste provides a sound basis for the planning process. As part of comprehensive decommissioning studies for Nordic NPPs, Westinghouse has developed the decommissioning inventories that have been used for estimations of the duration of specific work packages and the corresponding costs. As part of creating the design basis for a national repository for decommissioning waste, the total production of different categories of waste packages has also been predicted. Studsvik has developed a risk based concept for categorization and handling of the generated waste using six different categories with a span from extremely small risk for radiological contamination to high level waste. The two companies have recently joined their skills in the area of decommissioning on selected market in a consortium named 'ndcon' to further strengthen the proposed process. Depending on the risk for radiological contamination or the radiological properties and other properties of importance for waste management, treatment routes are proposed with well-defined and proven methods for on-site or off-site treatment, activity determination and conditioning. The system is based on a graded approach philosophy aiming for high confidence and sustainability, aiming for re-use and recycling where found applicable. The objective is to establish a process where all dismantled material has a pre-determined treatment route. These routes should through measurements, categorization, treatment, conditioning, intermediate storage and final disposal be designed to provide a steady, un-disturbed flow of material to avoid interruptions. Bottle

  8. Limnological and ecological methods: approaches, and sampling strategies for middle Xingu River in the area of influence of future Belo Monte Power Plant.

    PubMed

    Tundisi, J G; Matsumura-Tundisi, T; Tundisi, J E M; Faria, C R L; Abe, D S; Blanco, F; Rodrigues Filho, J; Campanelli, L; Sidagis Galli, C; Teixeira-Silva, V; Degani, R; Soares, F S; Gatti Junior, P

    2015-08-01

    In this paper the authors describe the limnological approaches, the sampling methodology, and strategy adopted in the study of the Xingu River in the area of influence of future Belo Monte Power Plant. The river ecosystems are characterized by unidirectional current, highly variable in time depending on the climatic situation the drainage pattern an hydrological cycle. Continuous vertical mixing with currents and turbulence, are characteristic of these ecosystems. All these basic mechanisms were taken into consideration in the sampling strategy and field work carried out in the Xingu River Basin, upstream and downstream the future Belo Monte Power Plant Units. PMID:26691072

  9. Global History. A Curriculum Guide. Third Semester. Theme VI: Nineteenth Century Imperialism Affected the Imperial Powers and the Colonies. Teacher Strategies. Experimental Edition.

    ERIC Educational Resources Information Center

    New York City Board of Education, Brooklyn, NY. Div. of Curriculum and Instruction.

    Designed to assist teachers and supervisors in the implementation of the global history course, this bulletin presents learning activities which include the rationale, performance objectives, and teaching strategies related to Theme VI entitled, "Nineteenth Century Imperialism Affected the Imperial Powers and the Colonies." This theme has seven…

  10. Joint US/Russian study on the development of a decommissioning strategy plan for RBMK-1000 unit No. 1 at the Leningrad Nuclear Power Plant

    SciTech Connect

    1997-12-01

    The objective of this joint U.S./Russian study was to develop a safe, technically feasible, economically acceptable strategy for decommissioning Leningrad Nuclear Power Plant (LNPP) Unit No. 1 as a representative first-generation RBMK-1000 reactor. The ultimate goal in developing the decommissioning strategy was to select the most suitable decommissioning alternative and end state, taking into account the socioeconomic conditions, the regulatory environment, and decommissioning experience in Russia. This study was performed by a group of Russian and American experts led by Kurchatov Institute for the Russian efforts and by the Pacific Northwest National Laboratory for the U.S. efforts and for the overall project.

  11. Optimal design and control strategies for novel combined heat and power (CHP) fuel cell systems. Part I of II, datum design conditions and approach.

    SciTech Connect

    Colella, Whitney G.

    2010-06-01

    Energy network optimization (ENO) models identify new strategies for designing, installing, and controlling stationary combined heat and power (CHP) fuel cell systems (FCSs) with the goals of (1) minimizing electricity and heating costs for building owners and (2) reducing emissions of the primary greenhouse gas (GHG) - carbon dioxide (CO{sub 2}). A goal of this work is to employ relatively inexpensive simulation studies to discover more financially and environmentally effective approaches for installing CHP FCSs. ENO models quantify the impact of different choices made by power generation operators, FCS manufacturers, building owners, and governments with respect to two primary goals - energy cost savings for building owners and CO{sub 2} emission reductions. These types of models are crucial for identifying cost and CO{sub 2} optima for particular installations. Optimal strategies change with varying economic and environmental conditions, FCS performance, the characteristics of building demand for electricity and heat, and many other factors. ENO models evaluate both 'business-as-usual' and novel FCS operating strategies. For the scenarios examined here, relative to a base case of no FCSs installed, model results indicate that novel strategies could reduce building energy costs by 25% and CO{sub 2} emissions by 80%. Part I of II articles discusses model assumptions and methodology. Part II of II articles illustrates model results for a university campus town and generalizes these results for diverse communities.

  12. Analysis of Strategies for Multiple Emissions from Electric Power SO2, NOX, CO2, Mercury and RPS

    EIA Publications

    2001-01-01

    At the request of the Subcommittee, the Energy Information Administration prepared an initial report that focused on the impacts of reducing power sector NOx, SO2, and CO2 emissions. The current report extends the earlier analysis to add the impacts of reducing power sector mercury emissions and introducing renewable portfolio standard (RPS) requirements.

  13. Increasing Parent Involvement Knowledge and Strategies at the Preservice Level: The Power in Using a Systematic Professional Development Approach

    ERIC Educational Resources Information Center

    Ferrara, Margaret M.

    2009-01-01

    This study describes various strategies used by a university educator to integrate parent involvement curriculum into pre-existing teacher preparation courses. This curriculum infusion was not only effective in increasing preservice teacher knowledge but also in raising course instructors' level of awareness about the importance and necessity of…

  14. A New Vision for Teacher Professional Growth & Support: Six Steps to a More Powerful School System Strategy

    ERIC Educational Resources Information Center

    Education Resource Strategies, 2013

    2013-01-01

    One of a series of Education Resource Strategies (ERS) publications and tools, this paper explores important ways to organize and invest in Professional Growth & Support that strengthen teaching capacity and effectiveness at the system level. It draws on research, ERS experience with urban school systems nationwide, and detailed analyses of…

  15. Definitional Hegemony as a Public Relations Strategy: The Rhetoric of the Nuclear Power Industry after Three Mile Island.

    ERIC Educational Resources Information Center

    Dionisopoulos, George N.; Crable, Richard E.

    1988-01-01

    Examines (1) definitional hegemony as one of several rhetorical options available to issue managers; (2) the post-accident rhetorical context of the Three Mile Island nuclear crisis; and (3) the specific strategies utilized to deal with this crisis. Assesses the nuclear industry's public relations efforts. (MS)

  16. Identifying/Quantifying Environmental Trade-offs Inherent in GHG Reduction Strategies for Coal-Fired Power.

    PubMed

    Schivley, Greg; Ingwersen, Wesley W; Marriott, Joe; Hawkins, Troy R; Skone, Timothy J

    2015-07-01

    Improvements to coal power plant technology and the cofired combustion of biomass promise direct greenhouse gas (GHG) reductions for existing coal-fired power plants. Questions remain as to what the reduction potentials are from a life cycle perspective and if it will result in unintended increases in impacts to air and water quality and human health. This study provides a unique analysis of the potential environmental impact reductions from upgrading existing subcritical pulverized coal power plants to increase their efficiency, improving environmental controls, cofiring biomass, and exporting steam for industrial use. The climate impacts are examined in both a traditional-100 year GWP-method and a time series analysis that accounts for emission and uptake timing over the life of the power plant. Compared to fleet average pulverized bed boilers (33% efficiency), we find that circulating fluidized bed boilers (39% efficiency) may provide GHG reductions of about 13% when using 100% coal and reductions of about 20-37% when cofiring with 30% biomass. Additional greenhouse gas reductions from combined heat and power are minimal if the steam coproduct displaces steam from an efficient natural gas boiler. These upgrades and cofiring biomass can also reduce other life cycle impacts, although there may be increased impacts to water quality (eutrophication) when using biomass from an intensely cultivated source. Climate change impacts are sensitive to the timing of emissions and carbon sequestration as well as the time horizon over which impacts are considered, particularly for long growth woody biomass. PMID:26001040

  17. Youth Development from the Trenches: A Practitioner Examines the Research, His Experience, and Discovers a Powerful New Youth Development Strategy

    ERIC Educational Resources Information Center

    Miller, Rick

    2012-01-01

    "You can mess all you want with instruction, curriculum, policy, and program strategies, and while all that is important, it doesn't substitute for the basics. We need adults who care about us as people and believe in us when no one else does, even when we don't seem to care about ourselves." Why do some children excel and some struggle? Why are…

  18. Electric power 2007

    SciTech Connect

    2007-07-01

    Subjects covered include: power industry trends - near term fuel strategies - price/quality/delivery/opportunity; generating fleet optimization and plant optimization; power plant safety and security; coal power plants - upgrades and new capacity; IGCC, advanced combustion and CO{sub 2} capture technologies; gas turbine and combined cycle power plants; nuclear power; renewable power; plant operations and maintenance; power plant components - design and operation; environmental; regulatory issues, strategies and technologies; and advanced energy strategies and technologies. The presentations are in pdf format.

  19. Biodiesel Drives Florida Power & Light's EPAct Alternative Compliance Strategy; EPAct Alternative Fuel Transportation Program: Success Story (Fact Sheet)

    SciTech Connect

    Not Available

    2010-05-01

    This success story highlights how Florida Power & Light Company has successfully complied with the Energy Policy Act of 1992 (EPAct) through Alternative Compliance using biodiesel technologies and how it has become a biofuel leader, reducing petroleum use and pollutant emissions throughout Florida.

  20. Reducing start-up time and minimizing energy losses of Microbial Fuel Cells using Maximum Power Point Tracking strategy

    NASA Astrophysics Data System (ADS)

    Molognoni, Daniele; Puig, Sebastià; Balaguer, M. Dolors; Liberale, Alessandro; Capodaglio, Andrea G.; Callegari, Arianna; Colprim, Jesús

    2014-12-01

    Microbial Fuel Cells (MFCs) are considered to be an environmental friendly energy conversion technology. The main limitations that delay their industrialization include low current and power densities achievable and long start-up times. Maximum Power Point Tracking (MPPT) has been proposed as a method to enhance MFCs electrical performances. However, the specialized literature is still lacking of experimental works on scaled-up reactors and/or real wastewater utilization. This study evaluates the impact of a MPPT system applied to MFCs treating swine wastewater in terms of start-up time and long-term performance. For this purpose, two replicate cells were compared, one with applied MPPT control and one working with fixed resistance. Both MFCs were continuously fed with swine wastewater to validate the control system under real and dynamic conditions. The study demonstrated that the automatic resistance control was able to reduce the start-up time of about one month. Moreover, MPPT system increased of 40% the Coulombic efficiency at steady-state conditions, reduced energy losses associated with anode and cathode reactions and limited methanogenic activity in the anode chamber. A power density of 5.0 ± 0.2 W m-3 NAC was achieved feeding the system at an organic loading rate of 10 kg COD m-3 d-1.

  1. Planning for future uncertainties in electric power generation; An analysis of transitional strategies for reduction of carbon and sulfur emissions

    SciTech Connect

    Tabors, R.D.; Monroe, B.L. III . Lab. for Electromagnetic and Electronic Systems)

    1991-11-01

    The objective of this paper is to identify strategies for the U.S. electric utility industry for reduction of both acid rain producing and global warming gasses. The research used the EPRI Electric Generation Expansion Analysis System (EGEAS) utility optimization/simulation modeling structure and the EPRI developed regional utilities. It focuses on the North East and East Central region of the U.S. Strategies identified were fuel switching -- predominantly between coal and natural gas, mandated emission limits, and a carbon tax. The overall conclusions of the study are that using less (conservation) will always benefit Carbon Emissions but may or may not benefit Acid Rain emissions by the off setting forces of improved performance of new plant as opposed to reduced overall consumption of final product. Results of the study are highly utility and regional demand specific. The study showed, however, that significant reductions in both acid rain and global warming gas production could be achieved with relatively small increases in the overall cost of production of electricity and that the current dispatch logics available to the utility control rooms were adequate to reschedule dispatch to meet these objectives.

  2. Hybrid Stochastic Search Technique based Suboptimal AGC Regulator Design for Power System using Constrained Feedback Control Strategy

    NASA Astrophysics Data System (ADS)

    Ibraheem, Omveer, Hasan, N.

    2010-10-01

    A new hybrid stochastic search technique is proposed to design of suboptimal AGC regulator for a two area interconnected non reheat thermal power system incorporating DC link in parallel with AC tie-line. In this technique, we are proposing the hybrid form of Genetic Algorithm (GA) and simulated annealing (SA) based regulator. GASA has been successfully applied to constrained feedback control problems where other PI based techniques have often failed. The main idea in this scheme is to seek a feasible PI based suboptimal solution at each sampling time. The feasible solution decreases the cost function rather than minimizing the cost function.

  3. State strategies of governance in biomedical innovation: aligning conceptual approaches for understanding 'Rising Powers' in the global context

    PubMed Central

    2011-01-01

    Background 'Innovation' has become a policy focus in its own right in many states as they compete to position themselves in the emerging knowledge economies. Innovation in biomedicine is a global enterprise in which 'Rising Power' states figure prominently, and which undoubtedly will re-shape health systems and health economies globally. Scientific and technological innovation processes and policies raise difficult issues in the domains of science/technology, civil society, and the economic and healthcare marketplace. The production of knowledge in these fields is complex, uncertain, inter-disciplinary and inter-institutional, and subject to a continuing political struggle for advantage. As part of this struggle, a wide variety of issues - regulation, intellectual property, ethics, scientific boundaries, healthcare market formation - are raised and policy agendas negotiated. Methods A range of social science disciplines and approaches have conceptualised such innovation processes. Against a background of concepts such as the competition state and the developmental state, and national innovation systems, we give an overview of a range of approaches that have potential for advancing understanding of governance of global life science and biomedical innovation, with special reference to the 'Rising Powers', in order to examine convergences and divergences between them. Conceptual approaches that we focus on include those drawn from political science/political economy, sociology of technology; Innovation Studies and Science & Technology Studies. The paper is part of a project supported by the UK ESRC's Rising Powers programme. Results We show convergences and complementarities between the approaches discussed, and argue that the role of the national state itself has become relatively neglected in much of the relevant theorising. Conclusions We conclude that an approach is required that enables innovation and governance to be seen as 'co-producing' each other in a multi

  4. Evaluation of steroidomics by liquid chromatography hyphenated to mass spectrometry as a powerful analytical strategy for measuring human steroid perturbations.

    PubMed

    Jeanneret, Fabienne; Tonoli, David; Rossier, Michel F; Saugy, Martial; Boccard, Julien; Rudaz, Serge

    2016-01-22

    This review presents the evolution of steroid analytical techniques, including gas chromatography coupled to mass spectrometry (GC-MS), immunoassay (IA) and targeted liquid chromatography coupled to mass spectrometry (LC-MS), and it evaluates the potential of extended steroid profiles by a metabolomics-based approach, namely steroidomics. Steroids regulate essential biological functions including growth and reproduction, and perturbations of the steroid homeostasis can generate serious physiological issues; therefore, specific and sensitive methods have been developed to measure steroid concentrations. GC-MS measuring several steroids simultaneously was considered the first historical standard method for analysis. Steroids were then quantified by immunoassay, allowing a higher throughput; however, major drawbacks included the measurement of a single compound instead of a panel and cross-reactivity reactions. Targeted LC-MS methods with selected reaction monitoring (SRM) were then introduced for quantifying a small steroid subset without the problems of cross-reactivity. The next step was the integration of metabolomic approaches in the context of steroid analyses. As metabolomics tends to identify and quantify all the metabolites (i.e., the metabolome) in a specific system, appropriate strategies were proposed for discovering new biomarkers. Steroidomics, defined as the untargeted analysis of the steroid content in a sample, was implemented in several fields, including doping analysis, clinical studies, in vivo or in vitro toxicology assays, and more. This review discusses the current analytical methods for assessing steroid changes and compares them to steroidomics. Steroids, their pathways, their implications in diseases and the biological matrices in which they are analysed will first be described. Then, the different analytical strategies will be presented with a focus on their ability to obtain relevant information on the steroid pattern. The future technical

  5. 'Supramolecular wrapping chemistry' by helix-forming polysaccharides: a powerful strategy for generating diverse polymeric nano-architectures.

    PubMed

    Numata, Munenori; Shinkai, Seiji

    2011-02-21

    We have exploited novel supramolecular wrapping techniques by helix-forming polysaccharides, β-1,3-glucans, which have strong tendency to form regular helical structures on versatile nanomaterials in an induced-fit manner. This approach is totally different from that using the conventional interpolymer interactions seen in both natural and synthetic polymeric architectures, and therefore has potential to create novel polymeric architectures with diverse and unexpected functionalities. The wrapping by β-1,3-glucans enforces the entrapped guest polymer to adopt helical or twisted conformations through the convergent interpolymer interactions. On the contrary, the wrapping by chemically modified semi-artificial β-1,3-glucans can bestow the divergent self-assembling abilities on the entrapped guest polymer to create hierarchical polymeric architectures, where the polymer/β-1,3-glucan composite acts as a huge one-dimensional building block. Based on the established wrapping strategy, we have further extended the wrapping techniques toward the creation of three-dimensional polymeric architectures, in which the polymer/β-1,3-glucan composite behaves as a sort of amphiphilic block copolymers. The present wrapping system would open several paths to accelerate the development of the polymeric supramolecular assembly systems, giving the strong stimuli to the frontier of polysaccharide-based functional chemistry. PMID:21246150

  6. Socio-economic and scientific premises for forming the strategies against malaria in Russia under Soviet power.

    PubMed

    Tchesnova, L

    1998-06-01

    The rapid spread of malaria in the 1920s-early '30s in the USSR was a result of Stalin's social and demographic policy. The Soviet government needed to elaborate the special complex of organisational and applied scientific measures concerning the eradication of malaria. The Central Malaria Commission and a network of antimalaria stations were created. In the 1930s and '40s malaria studies were institutionalised. A system of Medical Research Institutes was set up in the Soviet Union. Antimalaria congresses and periodical special issues helped coordinate their activities. Russian parasitologists worked out new approaches and methods of the comprehensive control of malaria foci. During World War II (1941-1945), the epidemiological situation was aggravated and antimalaria measures reduced. In the years 1945-1960 Beklemishev with his scientific school worked out the concept of landscape malariology and of "vital scheme of the species". This concept formed the basis for realising the malaria eradication strategy. In 1961 the WHO Malaria Eradication Department ascertained the liquidation of all types of malaria in Russia as epidemics. PMID:9653737

  7. Photon harvesting, coloring and polarizing in photovoltaic cell integrated color filters: efficient energy routing strategies for power-saving displays.

    PubMed

    Wen, Long; Chen, Qin; Song, Shichao; Yu, Yan; Jin, Lin; Hu, Xin

    2015-07-01

    We describe the integral electro-optical strategies that combine the functionalities of photovoltaic (PV) electricity generation and color filtering as well as polarizing to realize more efficient energy routing in display technology. Unlike the conventional pigment-based filters and polarizers, which absorb substantial amounts of unwanted spectral components and dissipate them in the form of heat, we propose converting the energy of those photons into electricity by constructing PV cell-integrated color filters based on a selectively transmitting aluminum (Al) rear electrode perforated with nanoholes (NHs). Combining with a dielectric-metal-dielectric (DMD) front electrode, the devices were optimized to enable efficient cavity-enhanced photon recycling in the PV functional layers. We perform a comprehensive theoretical and numerical analysis to explore the extraordinary optical transmission (EOT) through the Al NHs and identify basic design rules for achieving structural coloring or polarizing in our PV color filters. We show that the addition of thin photoactive polymer layers on the symmetrically configured Al NH electrode narrows the bandwidth of the EOT-assisted high-pass light filtering due to the strongly damped anti-symmetric coupling of the surface modes excited on the front and rear surface of the Al NHs, which facilitates the whole visible coloring with relatively high purity for the devices. By engineering the cut-off characteristics of the plasmonic waveguide mode supported by the circular or ellipsoidal Al NHs, beyond the photon recycling capacity, PV color filters and PV polarizing color filters that allow polarization-insensitive and strong polarization-anisotropic color filtering were demonstrated. The findings presented here may shed some light on expanding the utilization of PV electricity generation across new-generation energy-saving electrical display devices. PMID:26062682

  8. Photon harvesting, coloring and polarizing in photovoltaic cell integrated color filters: efficient energy routing strategies for power-saving displays

    NASA Astrophysics Data System (ADS)

    Wen, Long; Chen, Qin; Song, Shichao; Yu, Yan; Jin, Lin; Hu, Xin

    2015-07-01

    We describe the integral electro-optical strategies that combine the functionalities of photovoltaic (PV) electricity generation and color filtering as well as polarizing to realize more efficient energy routing in display technology. Unlike the conventional pigment-based filters and polarizers, which absorb substantial amounts of unwanted spectral components and dissipate them in the form of heat, we propose converting the energy of those photons into electricity by constructing PV cell-integrated color filters based on a selectively transmitting aluminum (Al) rear electrode perforated with nanoholes (NHs). Combining with a dielectric-metal-dielectric (DMD) front electrode, the devices were optimized to enable efficient cavity-enhanced photon recycling in the PV functional layers. We perform a comprehensive theoretical and numerical analysis to explore the extraordinary optical transmission (EOT) through the Al NHs and identify basic design rules for achieving structural coloring or polarizing in our PV color filters. We show that the addition of thin photoactive polymer layers on the symmetrically configured Al NH electrode narrows the bandwidth of the EOT-assisted high-pass light filtering due to the strongly damped anti-symmetric coupling of the surface modes excited on the front and rear surface of the Al NHs, which facilitates the whole visible coloring with relatively high purity for the devices. By engineering the cut-off characteristics of the plasmonic waveguide mode supported by the circular or ellipsoidal Al NHs, beyond the photon recycling capacity, PV color filters and PV polarizing color filters that allow polarization-insensitive and strong polarization-anisotropic color filtering were demonstrated. The findings presented here may shed some light on expanding the utilization of PV electricity generation across new-generation energy-saving electrical display devices.

  9. Strategy making and power in environmental assessments. Lessons from the establishment of an out-of-town shopping centre in Vaesteras, Sweden

    SciTech Connect

    Isaksson, Karolina; Storbjoerk, Sofie

    2012-04-15

    This paper seeks to provide deeper insights into how EA ineffectiveness is produced in land use planning practice. This is explored in a study of local development planning in the city of Vaesteras, Sweden. The case in question is the development of a large out-of-town shopping centre, propelled by the establishment of a new IKEA furniture store. The Healey (2007) framework of planning as strategy making is applied as an analytical framework, together with a focus on power-knowledge relations. In the analysis, we identify a range of mechanisms that produced ineffectiveness by limiting the role of environmental knowledge throughout the planning process. The specific mechanisms we identified were related to the overall consensus perspective in local development strategies and plans, a lack of concretisation and integration of various policies and strategies, a range of exclusion mechanisms and an overall focus on mitigation and benefits of the process in question. In practice, these mechanisms were closely intertwined. Our main conclusion is, consequently, that increased effectiveness of EA would require fundamental transformation of the norms, frameworks and routines that implicitly and explicitly guide land use planning in practice. - Highlights: Black-Right-Pointing-Pointer We analyse how EA-ineffectiveness is produced in land use planning practice. Black-Right-Pointing-Pointer Several mechanisms produce EA-ineffectiveness throughout the whole planning process. Black-Right-Pointing-Pointer These mechanisms are often closely intertwined and mutually reinforcing each other. Black-Right-Pointing-Pointer Enhancing EA-effectiveness requires a fundamental shift of the norms, frameworks and routines shaping planning practice.

  10. Membrane fouling and anti-fouling strategies using RO retentate from a municipal water recycling plant as the feed for osmotic power generation.

    PubMed

    Chen, Si Cong; Amy, Gary L; Chung, Tai-Shung

    2016-01-01

    RO retentate from a municipal water recycling plant is considered as a potential feed stream for osmotic power generation in this paper. The feasibility of using RO retentate from a municipal water recycling plant was examined from two aspects: (a) the membrane fouling propensity of RO retentate, and (b) the efficacy of anti-fouling strategies. The membranes used in this study were the inner selective thin film composite polyethersulfone (TFC/PES) hollow fiber membranes, which possessed a high water permeability and good mechanical strength. Scaling by phosphate salts was found to be one possible inorganic fouling on the innermost layer of the PES membrane, whereas silica fouling was observed to be the governing fouling on the outmost surface of the PES membrane. Two anti-fouling pretreatments, i.e., pH adjustment and anti-scalant pre-treatment for the feed stream, were studied and found to be straightforward and effective. Using RO retentate at pH 7.2 as the feed and 1 M NaCl as the draw solution, the average power density was 7.3 W/m(2) at 20 bar. The average power density increased to 12.6 W/m(2) by modifying RO retentate with an initial pH value of 5.5 using HCl and to 13.4 W/m(2) by adding 1.1 mM ethylenediaminetetraacetic acid (EDTA). Moreover, the flux recovery of the fouled membranes, without the indicated pretreatments, reached 84.9% using deionized (DI) water flushing and 95.0% using air bubbling under a high crossflow velocity of 23.3 cm/s (Re = 2497) for 30 min. After pretreatment by pH adjustment, the flux recovery increased to 94.6% by DI water flushing and 100.0% by air bubbling. After pretreatment by adding 1.1 mM EDTA into RO retentate, flux was almost fully restored by physical cleaning by DI water flushing and air bubbling. These results provide insight into developing an effective pretreatment by either pH adjustment or EDTA addition before PRO and physical cleaning methods by DI water flushing and air bubbling for membrane used in

  11. A lab-in-a-droplet bioassay strategy for centrifugal microfluidics with density difference pumping, power to disc and bidirectional flow control.

    PubMed

    Wang, Guanghui; Ho, Ho-Pui; Chen, Qiulan; Yang, Alice Kar-Lai; Kwok, Ho-Chin; Wu, Shu-Yuen; Kong, Siu-Kai; Kwan, Yiu-Wa; Zhang, Xuping

    2013-09-21

    In this paper, we present a lab-in-a-droplet bioassay strategy for a centrifugal microfluidics or lab-on-a-disc (LOAD) platform with three important advancements including density difference pumping, power to disc and bidirectional flow control. First, with the water based bioassay droplets trapped in a micro-channel filled with mineral oil, centrifugal force due to the density difference between the water and oil phases actuates droplet movement while the oil based medium remains stationary. Second, electricity is coupled to the rotating disc through a split-core transformer, thus enabling on-chip real-time heating in selected areas as desired and wireless programmable functionality. Third, an inertial mechanical structure is proposed to achieve bidirectional flow control within the spinning disc. The droplets can move back and forth between two heaters upon changing the rotational speed. Our platform is an essential and versatile solution for bioassays such as those involving DNA amplification, where localized temperature cycling is required. Finally, without the loss of generality, we demonstrate the functionality of our platform by performing real-time polymerase chain reaction (RT-PCR) in a linear microchannel made with PTFE (Teflon) micro-tubing. PMID:23881222

  12. Improving Motor Activity Assessment in Depression: Which Sensor Placement, Analytic Strategy and Diurnal Time Frame Are Most Powerful in Distinguishing Patients from Controls and Monitoring Treatment Effects

    PubMed Central

    Deuschle, Michael; Gilles, Maria; Hill, Holger; Limberger, Matthias F.; Ebner-Priemer, Ulrich W.

    2015-01-01

    Background Abnormalities in motor activity represent a central feature in major depressive disorder. However, measurement issues are poorly understood, limiting the use of objective measurement of motor activity for diagnostics and treatment monitoring. Methods To improve measurement issues, especially sensor placement, analytic strategies and diurnal effects, we assessed motor activity in depressed patients at the beginning (MD; n=27) and after anti-depressive treatment (MD-post; n=18) as well as in healthy controls (HC; n=16) using wrist- and chest-worn accelerometers. We performed multiple analyses regarding sensor placements, extracted features, diurnal variation, motion patterns and posture to clarify which parameters are most powerful in distinguishing patients from controls and monitoring treatment effects. Results Whereas most feature-placement combinations revealed significant differences between groups, acceleration (wrist) distinguished MD from HC (d=1.39) best. Frequency (vertical axis chest) additionally differentiated groups in a logistic regression model (R2=0.54). Accordingly, both amplitude (d=1.16) and frequency (d=1.04) showed alterations, indicating reduced and decelerated motor activity. Differences between MD and HC in gestures (d=0.97) and walking (d=1.53) were found by data analysis from the wrist sensor. Comparison of motor activity at the beginning and after MD-treatment largely confirms our findings. Limitations Sample size was small, but sufficient for the given effect sizes. Comparison of depressed in-patients with non-hospitalized controls might have limited motor activity differences between groups. Conclusions Measurement of wrist-acceleration can be recommended as a basic technique to capture motor activity in depressed patients as it records whole body movement and gestures. Detailed analyses showed differences in amplitude and frequency denoting that depressed patients walked less and slower. PMID:25885258

  13. A Passive Heat Maintenance Strategy Implemented during a Simulated Half-Time Improves Lower Body Power Output and Repeated Sprint Ability in Professional Rugby Union Players

    PubMed Central

    Russell, Mark; West, Daniel J.; Briggs, Marc A.; Bracken, Richard M.; Cook, Christian J.; Giroud, Thibault; Gill, Nicholas; Kilduff, Liam P.

    2015-01-01

    Reduced physical performance has been observed following the half-time period in team sports players, likely due to a decrease in muscle temperature during this period. We examined the effects of a passive heat maintenance strategy employed between successive exercise bouts on core temperature (Tcore) and subsequent exercise performance. Eighteen professional Rugby Union players completed this randomised and counter-balanced study. After a standardised warm-up (WU) and 15 min of rest, players completed a repeated sprint test (RSSA 1) and countermovement jumps (CMJ). Thereafter, in normal training attire (Control) or a survival jacket (Passive), players rested for a further 15 min (simulating a typical half-time) before performing a second RSSA (RSSA 2) and CMJ’s. Measurements of Tcore were taken at baseline, post-WU, pre-RSSA 1, post-RSSA 1 and pre-RSSA 2. Peak power output (PPO) and repeated sprint ability was assessed before and after the simulated half-time. Similar Tcore responses were observed between conditions at baseline (Control: 37.06±0.05°C; Passive: 37.03±0.05°C) and for all other Tcore measurements taken before half-time. After the simulated half-time, the decline in Tcore was lower (-0.74±0.08% vs. -1.54±0.06%, p<0.001) and PPO was higher (5610±105 W vs. 5440±105 W, p<0.001) in the Passive versus Control condition. The decline in PPO over half-time was related to the decline in Tcore (r = 0.632, p = 0.005). In RSSA 2, best, mean and total sprint times were 1.39±0.17% (p<0.001), 0.55±0.06% (p<0.001) and 0.55±0.06% (p<0.001) faster for Passive versus Control. Passive heat maintenance reduced declines in Tcore that were observed during a simulated half-time period and improved subsequent PPO and repeated sprint ability in professional Rugby Union players. PMID:25785393

  14. A passive heat maintenance strategy implemented during a simulated half-time improves lower body power output and repeated sprint ability in professional Rugby Union players.

    PubMed

    Russell, Mark; West, Daniel J; Briggs, Marc A; Bracken, Richard M; Cook, Christian J; Giroud, Thibault; Gill, Nicholas; Kilduff, Liam P

    2015-01-01

    Reduced physical performance has been observed following the half-time period in team sports players, likely due to a decrease in muscle temperature during this period. We examined the effects of a passive heat maintenance strategy employed between successive exercise bouts on core temperature (Tcore) and subsequent exercise performance. Eighteen professional Rugby Union players completed this randomised and counter-balanced study. After a standardised warm-up (WU) and 15 min of rest, players completed a repeated sprint test (RSSA 1) and countermovement jumps (CMJ). Thereafter, in normal training attire (Control) or a survival jacket (Passive), players rested for a further 15 min (simulating a typical half-time) before performing a second RSSA (RSSA 2) and CMJ's. Measurements of Tcore were taken at baseline, post-WU, pre-RSSA 1, post-RSSA 1 and pre-RSSA 2. Peak power output (PPO) and repeated sprint ability was assessed before and after the simulated half-time. Similar Tcore responses were observed between conditions at baseline (Control: 37.06±0.05°C; Passive: 37.03±0.05°C) and for all other Tcore measurements taken before half-time. After the simulated half-time, the decline in Tcore was lower (-0.74±0.08% vs. -1.54±0.06%, p<0.001) and PPO was higher (5610±105 W vs. 5440±105 W, p<0.001) in the Passive versus Control condition. The decline in PPO over half-time was related to the decline in Tcore (r = 0.632, p = 0.005). In RSSA 2, best, mean and total sprint times were 1.39±0.17% (p<0.001), 0.55±0.06% (p<0.001) and 0.55±0.06% (p<0.001) faster for Passive versus Control. Passive heat maintenance reduced declines in Tcore that were observed during a simulated half-time period and improved subsequent PPO and repeated sprint ability in professional Rugby Union players. PMID:25785393

  15. Identifying/Quantifying Environmental Trade-offs Inherent in GHG Reduction Strategies for Coal-Fired Power. Environmental Science and Technology

    EPA Science Inventory

    Improvements to coal power plant technology and the co-fired combustion of biomass promise direct greenhouse gas (GHG) reductions for existing coal-fired power plants. Questions remain as to what the reduction potentials are from a life cycle perspective and if it will result in ...

  16. A new balancing three level three dimensional space vector modulation strategy for three level neutral point clamped four leg inverter based shunt active power filter controlling by nonlinear back stepping controllers.

    PubMed

    Chebabhi, Ali; Fellah, Mohammed Karim; Kessal, Abdelhalim; Benkhoris, Mohamed F

    2016-07-01

    In this paper is proposed a new balancing three-level three dimensional space vector modulation (B3L-3DSVM) strategy which uses a redundant voltage vectors to realize precise control and high-performance for a three phase three-level four-leg neutral point clamped (NPC) inverter based Shunt Active Power Filter (SAPF) for eliminate the source currents harmonics, reduce the magnitude of neutral wire current (eliminate the zero-sequence current produced by single-phase nonlinear loads), and to compensate the reactive power in the three-phase four-wire electrical networks. This strategy is proposed in order to gate switching pulses generation, dc bus voltage capacitors balancing (conserve equal voltage of the two dc bus capacitors), and to switching frequency reduced and fixed of inverter switches in same times. A Nonlinear Back Stepping Controllers (NBSC) are used for regulated the dc bus voltage capacitors and the SAPF injected currents to robustness, stabilizing the system and to improve the response and to eliminate the overshoot and undershoot of traditional PI (Proportional-Integral). Conventional three-level three dimensional space vector modulation (C3L-3DSVM) and B3L-3DSVM are calculated and compared in terms of error between the two dc bus voltage capacitors, SAPF output voltages and THDv, THDi of source currents, magnitude of source neutral wire current, and the reactive power compensation under unbalanced single phase nonlinear loads. The success, robustness, and the effectiveness of the proposed control strategies are demonstrated through simulation using Sim Power Systems and S-Function of MATLAB/SIMULINK. PMID:27018144

  17. Current strategies against invasive fungal infections in patients with aplastic anemia, strong power and weak weapon, a case report and review of literature.

    PubMed

    Zekavat, Omid Reza; Amanati, Ali; Saleh, Fazl; Abdolkarimi, Babak; Fathpour, Gholamreza; Badiee, Parisa; Geramizadeh, Bita

    2016-03-01

    We report an 18 year old boy with Aplastic anemia complicated by serious fungal rhinosinusitis. Despite prompt treatment and early repeated surgical debridements, he died after about more than 6 weeks of hard challenges with fungal infections. Current strategies against invasive fungal infections (IFIs) in patients with Aplastic anemia may be inadequate for the management of serious complications. Antifungal prophylaxis is highly recommended in pre-transplant period for severe form of Aplastic anemia. PMID:27047751

  18. Ephemeris Generation for ETS-VI and Its Effects on Pointing Strategies Adopted for Daytime Acquisition and Tracking

    NASA Astrophysics Data System (ADS)

    Owen, W. M., Jr.; Gillam, S. D.; Young, J. W.; Mayes, D. L.

    1996-10-01

    Critical to the success of the Ground/Orbiter Lasercomm Demonstration (GOLD) was the ability of the two telescopes at the Table Mountain Facility (TMF) to track the Japanese Engineering Test Satellite (ETS-VI). This article describes the process of generating pointing predictions from the satellite's orbital elements, experiments to determine the inherent pointing accuracy of the TMF telescopes, and the strategies developed for overcoming errors in the satellite's ephemeris. The combination of ephemeris precision, telescope-pointing precision, and low satellite contrast against the bright sky made daytime satellite acquisition a serious challenge. Inherent telescope-pointing error in right ascension, end play in the declination axis worm gear, and pointing error induced by the statistical errors in the ephemeris were thought to be the main sources of error in the telescope pointing.

  19. ALEGRA-HEDP validation strategy.

    SciTech Connect

    Garasi, Christopher Joseph; Mehlhorn, Thomas Alan; Trucano, Timothy Guy

    2006-01-01

    This report presents a initial validation strategy for specific SNL pulsed power program applications of the ALEGRA-HEDP radiation-magnetohydrodynamics computer code. The strategy is written to be (1) broadened and deepened with future evolution of particular specifications given in this version; (2) broadly applicable to computational capabilities other than ALEGRA-HEDP directed at the same pulsed power applications. The content and applicability of the document are highly constrained by the R&D thrust of the SNL pulsed power program. This means that the strategy has significant gaps, indicative of the flexibility required to respond to an ongoing experimental program that is heavily engaged in phenomena discovery.

  20. Real-Time Implementation of Type-2 FLC-Based Shunt Active Filter Control Strategies (p-q and Id-Iq) with Different Fuzzy MFs for Power Quality Improvement

    NASA Astrophysics Data System (ADS)

    Mikkili, Suresh; Panda, Anup Kumar

    2014-06-01

    This research article proposes the shunt active filter (SHAF) control strategies (p-q and Id-Iq), which are used to improve the power quality of the electrical network by mitigating the harmonics with the help of Type-2 fuzzy logic controller (Type-2 FLC) different membership functions (MFs). Three-phase reference current waveforms generated by proposed scheme are tracked by the three-phase voltage source converter in a hysteresis band control scheme. The performance of the proposed control strategies has been evaluated in terms of harmonic mitigation and DC link voltage regulation under various source conditions. In order to maintain DC link voltage constant and to generate the compensating reference currents, we have developed Type-2 FLC with different fuzzy MFs (trapezoidal, triangular and Gaussian). The SHAF with proposed Type-2 FLC using Gaussian MF is able to eliminate the uncertainty in the system and SHAF gains outstanding compensation abilities. The detailed real-time results using real-time digital simulator are presented to support the feasibility of proposed control strategies.

  1. Leyte `A` geothermal project optimization: Review of improved resource performance and power generation strategies for the greater Tongonan field. Export trade information

    SciTech Connect

    1992-11-01

    The Consultant Team (the team) visited the Philippines the weeks of October 24 and November 9, 1992, in order to review and discuss the resource and power generation optimization work underway for the Greater Tongonan Geothermal field on the island of Leyte being developed by the Philippine National Oil Company - Energy Development Corporation (PNOC-EDC). The team`s work is managed by PNOC-EDC and funded by the United States Trade and Development Program (USTDP).

  2. Conformal Coating Strategy Comprising N-doped Carbon and Conventional Graphene for Achieving Ultrahigh Power and Cyclability of LiFePO4.

    PubMed

    Zhang, Kan; Lee, Jeong-Taik; Li, Ping; Kang, Byoungwoo; Kim, Jung Hyun; Yi, Gi-Ra; Park, Jong Hyeok

    2015-10-14

    Surface carbon coating to improve the inherent poor electrical conductivity of lithium iron phosphate (LiFePO4, LFP) has been considered as most efficient strategy. Here, we also report one of the conventional methods for LFP but exhibiting a specific capacity beyond the theoretical value, ultrahigh rate performance, and excellent long-term cyclability: the specific capacity is 171.9 mAh/g (70 μm-thick electrode with ∼10 mg/cm(2) loading mass) at 0.1 C (17 mA/g) and retains 143.7 mAh/g at 10 C (1.7 A/g) and 95.8% of initial capacity at 10 C after 1000 cycles. It was found that the interior conformal N-C coating enhances the intrinsic conductivity of LFP nanorods (LFP NR) and the exterior reduced graphene oxide coating acts as an electrically conducting secondary network to electrically connect the entire electrode. The great electron transport mutually promoted with shorten Li diffusion length on (010) facet exposed LFP NR represents the highest specific capacity value recorded to date at 10 C and ultralong-term cyclability. This conformal carbon coating approach can be a promising strategy for the commercialization of LFP cathode in lithium ion batteries. PMID:26389552

  3. Power for nursing education.

    PubMed

    Glen, S

    1990-11-01

    The topic of power and politics is a recurrent theme in the nursing literature, but not, I wish to suggest, in the nursing educational literature. This paper introduces the topic of power as a nursing educational issue. It is divided into three sections: (a) what a concept of power might mean for nursing education; (b) the nature and form of power relationships within nursing education; and (c) the nature, form and efficacy of the current professional strategies to gain power. First, two definitions of power for nursing education are explored: (a) the power inherent in organizational structures; and (b) the notion of practising nursing education as an empowering profession. Next, a theoretical framework is applied to specific examples of power relationships within nursing education. Two views of power and their inter-relationship with decision-making in curriculum matters are described: 'overt conflict' and 'control of the institution's agenda'. It is argued that these still fail to pick up important instances of the strategies to gain power. Finally, examples of strategies used to gain power in colleges of nursing are made explicit. Concurrently, questions are raised in relation to their efficacy and alternative strategies more congruent with the role of professional educator are advocated. It is argued that nursing education's most lasting form of power will rest in the development of pedagogical knowledge expertise and a research basis: in essence, the development of an academic identity in nursing education. PMID:2269757

  4. Strategies for success

    SciTech Connect

    Burr, M.T.

    1993-04-01

    Some 30 companies are developing a majority of the private power facilities worldwide. Attributes such as financial strength, a proven track record, experience in related markets, and a well developed business strategy are keys to success in this complex marketplace. Key executives from four of these companies were interviewed for their perspective in this industry.

  5. Immunoaffinity capillary electrophoresis as a powerful strategy for the quantification of low-abundance biomarkers, drugs, and metabolites in biological matrices

    PubMed Central

    Guzman, Norberto A.; Blanc, Timothy; Phillips, Terry M.

    2009-01-01

    In the last few years, there has been a greater appreciation by the scientific community of how separation science has contributed to the advancement of biomedical research. Despite past contributions in facilitating several biomedical breakthroughs, separation sciences still urgently need the development of improved methods for the separation and detection of biological and chemical substances. In particular, the challenging task of quantifying small molecules and biomolecules, found in low abundance in complex matrices (e.g., serum), is a particular area in need of new high-efficiency techniques. The tandem or on-line coupling of highly selective antibody capture agents with the high-resolving power of CE is being recognized as a powerful analytical tool for the enrichment and quantification of ultra-low abundance analytes in complex matrices. This development will have a significant impact on the identification and characterization of many putative biomarkers and on biomedical research in general. Immunoaffinity CE (IACE) technology is rapidly emerging as the most promising method for the analysis of low-abundance biomarkers; its power comes from a three-step procedure: (i) bioselective adsorption and (ii) subsequent recovery of compounds from an immobilized affinity ligand followed by (iii) separation of the enriched compounds. This technology is highly suited to automation and can be engineered to as a multiplex instrument capable of routinely performing hundreds of assays per day. Furthermore, a significant enhancement in sensitivity can be achieved for the purified and enriched affinity targeted analytes. Thus, a compound that exists in a complex biological matrix at a concentration far below its LOD is easily brought to well within its range of quantification. The present review summarizes several applications of IACE, as well as a chronological description of the improvements made in the fabrication of the analyte concentrator-microreactor device leading

  6. Investigation of the Potential for Biofuel Blends in Residual Oil-Fired Power Generation Units as an Emissions Reduction Strategy for New York State

    SciTech Connect

    Krishna, C.R.; McDonald, R.

    2009-05-01

    There is a significant amount of oil, about 12.6 million barrels per year, used for power generation in New York State. The majority of it is residual oil. The primary reason for using residual oil probably is economic, as these fuels are cheaper than distillates. However, the stack emissions from the use of such fuels, especially in densely populated urban areas, can be a cause for concern. The emissions of concern include sulfur and nitrogen oxides and particulates, particularly PM 2.5. Blending with distillate (ASTM No.2) fuels may not reduce some or all of these emissions. Hence, a case can be made for blending with biofuels, such as biodiesel, as they tend to have very little fuel bound sulfur and nitrogen and have been shown in prior work at Brookhaven National Laboratory (BNL) to reduce NOx emissions as well in small boilers. Some of the research carried out at CANMET in Canada has shown potential reductions in PM with blending of biodiesel in distillate oil. There is also the benefit obtaining from the renewable nature of biofuels in reducing the net carbon dioxide emitted thus contributing to the reduction of green house gases that would otherwise be emitted to the atmosphere. The present project was conceived to examine the potential for such benefits of blending biofuels with residual oil. A collaboration was developed with personnel at the New York City Poletti Power Plant of the New York Power Authority. Their interest arose from an 800 MW power plant that was using residual oil and which was mandated to be shut down in 2010 because of environmental concerns. A blend of 20% biodiesel in residual oil had also been tested for a short period of about two days in that boiler a couple of years back. In this project, emission measurements including particulate measurements of PM2.5 were made in the commercial boiler test facility at BNL described below. Baseline tests were done using biodiesel as the blending biofuel. Biodiesel is currently and probably in

  7. Optimal operational strategies for a day-ahead electricity market in the presence of market power using multi-objective evolutionary algorithms

    NASA Astrophysics Data System (ADS)

    Rodrigo, Deepal

    2007-12-01

    This dissertation introduces a novel approach for optimally operating a day-ahead electricity market not only by economically dispatching the generation resources but also by minimizing the influences of market manipulation attempts by the individual generator-owning companies while ensuring that the power system constraints are not violated. Since economic operation of the market conflicts with the individual profit maximization tactics such as market manipulation by generator-owning companies, a methodology that is capable of simultaneously optimizing these two competing objectives has to be selected. Although numerous previous studies have been undertaken on the economic operation of day-ahead markets and other independent studies have been conducted on the mitigation of market power, the operation of a day-ahead electricity market considering these two conflicting objectives simultaneously has not been undertaken previously. These facts provided the incentive and the novelty for this study. A literature survey revealed that many of the traditional solution algorithms convert multi-objective functions into either a single-objective function using weighting schemas or undertake optimization of one function at a time. Hence, these approaches do not truly optimize the multi-objectives concurrently. Due to these inherent deficiencies of the traditional algorithms, the use of alternative non-traditional solution algorithms for such problems has become popular and widely used. Of these, multi-objective evolutionary algorithms (MOEA) have received wide acceptance due to their solution quality and robustness. In the present research, three distinct algorithms were considered: a non-dominated sorting genetic algorithm II (NSGA II), a multi-objective tabu search algorithm (MOTS) and a hybrid of multi-objective tabu search and genetic algorithm (MOTS/GA). The accuracy and quality of the results from these algorithms for applications similar to the problem investigated here

  8. Strategies for steam handling and H/sub 2/S abatement at geothermal power plants in The Geysers area of northern California

    SciTech Connect

    Morris, W.F.; Stephens, F.B.

    1981-08-05

    Strict limitations on the emission of H/sub 2/S from new geothermal power plants in The Geysers area of northern California have been imposed by Lake and Northern Sonoma County Air Pollution Control Districts. Lake County, under new source review rules, has stipulated that specific technologies shall be utilized to limit H/sub 2/S emissions to 5 lb/h as a condition for determination of compliance. The status of these technologies as well as other ongoing technology development efforts to conserve steam and abate H/sub 2/S are evaluated. Although projections indicate that it may be possible to meet the 5 lb/h limit, there is no firm assurance of achievement at this time because of the unproven, full-scale performance status of some key technologies specified by the air pollution control districts.

  9. Leadership Strategies for Managing Conflict.

    ERIC Educational Resources Information Center

    Kormanski, Chuck

    1982-01-01

    Discusses the impact of conflict in small group development theory. Views conflict as a positive, normally occurring behavior and presents leadership strategies involving withdrawal, suppression, integration, compromise, and power. Examines situational contingencies and presents a rationale for strategy selection and intervention. (Author)

  10. Soil sampling and analytical strategies for mapping fallout in nuclear emergencies based on the Fukushima Dai-ichi Nuclear Power Plant accident.

    PubMed

    Onda, Yuichi; Kato, Hiroaki; Hoshi, Masaharu; Takahashi, Yoshio; Nguyen, Minh-Long

    2015-01-01

    The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident resulted in extensive radioactive contamination of the environment via deposited radionuclides such as radiocesium and (131)I. Evaluating the extent and level of environmental contamination is critical to protecting citizens in affected areas and to planning decontamination efforts. However, a standardized soil sampling protocol is needed in such emergencies to facilitate the collection of large, tractable samples for measuring gamma-emitting radionuclides. In this study, we developed an emergency soil sampling protocol based on preliminary sampling from the FDNPP accident-affected area. We also present the results of a preliminary experiment aimed to evaluate the influence of various procedures (e.g., mixing, number of samples) on measured radioactivity. Results show that sample mixing strongly affects measured radioactivity in soil samples. Furthermore, for homogenization, shaking the plastic sample container at least 150 times or disaggregating soil by hand-rolling in a disposable plastic bag is required. Finally, we determined that five soil samples within a 3 m × 3-m area are the minimum number required for reducing measurement uncertainty in the emergency soil sampling protocol proposed here. PMID:24965965

  11. In-vessel Retention Strategy for High Power Reactors - K-INERI Final Report (includes SBLB Test Results for Task 3 on External Reactor Vessel Cooling (ERVC) Boiling Data and CHF Enhancement Correlations)

    SciTech Connect

    F. B. Cheung; J. Yang; M. B. Dizon; J. Rempe

    2005-01-01

    In-vessel retention (IVR) of core melt is a key severe accident management strategy adopted by some operating nuclear power plants and proposed for some advanced light water reactors (ALWRs). If there were inadequate cooling during a reactor accident, a significant amount of core material could become molten and relocate to the lower head of the reactor vessel, as happened in the Three Mile Island Unit 2 (TMI-2) accident. If it is possible to ensure that the vessel head remains intact so that relocated core materials are retained within the vessel, the enhanced safety associated with these plants can reduce concerns about containment failure and associated risk. For example, the enhanced safety of the Westinghouse Advanced 600 MWe PWR (AP600), which relied upon External Reactor Vessel Cooling (ERVC) for IVR, resulted in the U.S. Nuclear Regulatory Commission (US NRC) approving the design without requiring certain conventional features common to existing LWRs. However, it is not clear that currently proposed external reactor vessel cooling (ERVC) without additional enhancements could provide sufficient heat removal for higher-power reactors (up to 1500 MWe). Hence, a collaborative, three-year, U.S. - Korean International Nuclear Energy Research Initiative (INERI) project was completed in which the Idaho National Engineering and Environmental Laboratory (INEEL), Seoul National University (SNU), Pennsylvania State University (PSU), and the Korea Atomic Energy Research Institute (KAERI) investigated the performance of ERVC and an in-vessel core catcher (IVCC) to determine if IVR is feasible for reactors up to 1500 MWe.

  12. Literacy Strategies.

    ERIC Educational Resources Information Center

    North Carolina State Dept. of Public Instruction, Raleigh. Instructional Services.

    The literacy strategies in this guide provide practical suggestions for teachers, regardless of discipline, to help middle school and high school students move to Levels III and IV on the North Carolina End-of-Grade Reading/Competency Tests. The strategies in the guide are designed for use with "inefficient" readers (not nonreaders). After an…

  13. A new clustering strategy

    NASA Astrophysics Data System (ADS)

    Feng, Jian-xin; Tang, Jia-fu; Wang, Guang-xing

    2007-04-01

    On the basis of the analysis of clustering algorithm that had been proposed for MANET, a novel clustering strategy was proposed in this paper. With the trust defined by statistical hypothesis in probability theory and the cluster head selected by node trust and node mobility, this strategy can realize the function of the malicious nodes detection which was neglected by other clustering algorithms and overcome the deficiency of being incapable of implementing the relative mobility metric of corresponding nodes in the MOBIC algorithm caused by the fact that the receiving power of two consecutive HELLO packet cannot be measured. It's an effective solution to cluster MANET securely.

  14. Methods and Strategies: Talk Strategies

    ERIC Educational Resources Information Center

    Shea, Lauren M.; Shanahan, Therese B.

    2011-01-01

    This article discusses how to promote oral language development through science. The authors describe how they incorporate academic "talk strategies" into science lessons in a nonintrusive and meaningful manner. These talk strategies are adapted from the "Avenues" (2007) curriculum for English learners (ELs), which gives examples of cooperative…

  15. PowerSat: A technology demonstration of a solar power satellite

    NASA Technical Reports Server (NTRS)

    Sigler, Douglas L. (Editor); Riedman, John; Duracinski, Jon; Edwards, Joe; Brown, Garry; Webb, Ron; Platzke, Mike; Yuan, Xiaolin; Rogers, Pete; Khan, Afsar

    1994-01-01

    PowerSat is a preliminary design strategy for microwave wireless power transfer of solar energy. Solar power satellites convert solar power into microwave energy and use wireless power transmission to transfer the power to the Earth's surface. The PowerSat project will show how new developments in inflatable technology can be used to deploy solar panels and phased array antennas.

  16. Cetacean Strategies.

    ERIC Educational Resources Information Center

    Gilliland, Denise DelGrosso

    1991-01-01

    Suggested are activities about whales for children in schools not near the ocean. Activities designed to pique students' interest in whales and to investigate the size, breathing, buoyancy, and feeding strategies of whales are discussed. (CW)

  17. Self-powered sensors.

    PubMed

    Arechederra, Robert L; Minteer, Shelley D

    2011-06-01

    One of the problems associated with miniaturization and portability of sensors is the power supply. Power supplies, such as batteries, are difficult to miniaturize and require a sensor design that allows for easy replacement or recharging. This review describes the field of self-powered sensing, where the sensor itself provides the power for the sensing device. Most self-powered-sensing strategies employ either nuclear energy conversion or electrochemical energy conversion. Nuclear energy conversion is employed for radioisotope or nuclear reactor sensing. Electrochemical energy conversion is employed for chemical and biological sensing. This review details the common strategies for self-powered nuclear, chemical, and biological sensing and discusses the future of the technology. PMID:21359574

  18. Powerful Pedagogical Strategies in Initial Teacher Education

    ERIC Educational Resources Information Center

    Wilson, Elaine

    2005-01-01

    The development of beginning teachers' practice during a school placement is a multiplicity of mediated interaction between university and school based systems. Both systems have the common aim of training effective teachers. However day-to-day internal institution matters can cause tension between the learning goals set out for the beginning…

  19. History Alive! Six Powerful Constructivist Strategies.

    ERIC Educational Resources Information Center

    Bower, Bert; Lobdell, Jim

    1998-01-01

    Describes six activities from the "History Alive" program. These include an interactive slide lecture on the Great Depression, a photographic analysis regarding Mexican and Southwest culture, an experiential exercise concerning life on the assembly line, collages on Chinese belief systems, a response group on women's rights, and poetry writing.…

  20. [Potentiation strategies].

    PubMed

    Doumy, Olivier; Bennabi, Djamila; El-Hage, Wissam; Allaïli, Najib; Bation, Rémy; Bellivier, Frank; Holtzmann, Jérôme; Bubrovszky, Maxime; Camus, Vincent; Charpeaud, Thomas; Courvoisier, Pierre; d'Amato, Thierry; Garnier, Marion; Haesebaert, Frédéric; Bougerol, Thierry; Lançon, Christophe; Moliere, Fanny; Nieto, Isabel; Richieri, Raphaëlle; Saba, Ghassen; Courtet, Philippe; Vaiva, Guillaume; Leboyer, Marion; Llorca, Pierre-Michel; Aouizerate, Bruno; Haffen, Emmanuel

    2016-03-01

    Lithium is among the most classically recommended add-on therapeutic strategy for the management of depressive patients showing unsuccessful response to standard antidepressant medications. The effectiveness of the add-on strategy with lithium requires achieving plasma levels above 0.5 mEq/L. Mood-stabilizing antiepileptic drugs such as carbamazepine, valproate derivatives or lamotrigine have not demonstrated conclusive therapeutic effects for the management of depressive patients showing unsuccessful response to standard antidepressant medications. Thyroid hormones are considered among the currently recommended add-on therapeutic strategy for the management of depressive patients showing unsuccessful response to standard antidepressant medications. The effectiveness of the add-on strategy with thyroid hormones requires achieving plasma concentration of TSH close to the lower limits at the normal range (0.4 μUI/L) or even below it. Second-generation antipsychotics such as aripiprazole or quetiapine have consistently demonstrated significant therapeutic effects for the management of depressive patients showing unsuccessful response to standard antidepressant medications. Second-generation antipsychotics however require the careful monitoring of both cardiovascular and metabolic adverse effects. PMID:26970936

  1. New strategies in O M

    SciTech Connect

    Seeley, R.S.

    1993-10-01

    Companies that provide operations and maintenance (O M) services to independent power plants are changing their strategies in response to increasing cost pressures on owners. O M contractors are fine-tuning their approaches in several ways. Global contracts, new controls, and computerization are some of their strategies they are using. With these new approaches O M contractors can improve their services and project owners bottom lines.

  2. Strategy under uncertainty.

    PubMed

    Courtney, H; Kirkland, J; Viguerie, P

    1997-01-01

    At the heart of the traditional approach to strategy lies the assumption that by applying a set of powerful analytic tools, executives can predict the future of any business accurately enough to allow them to choose a clear strategic direction. But what happens when the environment is so uncertain that no amount of analysis will allow us to predict the future? What makes for a good strategy in highly uncertain business environments? The authors, consultants at McKinsey & Company, argue that uncertainty requires a new way of thinking about strategy. All too often, they say, executives take a binary view: either they underestimate uncertainty to come up with the forecasts required by their companies' planning or capital-budging processes, or they overestimate it, abandon all analysis, and go with their gut instinct. The authors outline a new approach that begins by making a crucial distinction among four discrete levels of uncertainty that any company might face. They then explain how a set of generic strategies--shaping the market, adapting to it, or reserving the right to play at a later time--can be used in each of the four levels. And they illustrate how these strategies can be implemented through a combination of three basic types of actions: big bets, options, and no-regrets moves. The framework can help managers determine which analytic tools can inform decision making under uncertainty--and which cannot. At a broader level, it offers executives a discipline for thinking rigorously and systematically about uncertainty and its implications for strategy. PMID:10174798

  3. Overview paper on nuclear power

    SciTech Connect

    Spiewak, I.; Cope, D.F.

    1980-09-01

    This paper was prepared as an input to ORNL's Strategic Planning Activity, ORNL National Energy Perspective (ONEP). It is intended to provide historical background on nuclear power, an analysis of the mission of nuclear power, a discussion of the issues, the technology choices, and the suggestion of a strategy for encouraging further growth of nuclear power.

  4. Space Station power system

    SciTech Connect

    Baraona, C.R.

    1984-04-01

    The strategies, reasoning, and planning guidelines used in the development of the United States Space Station Program are outlined. The power required to support Space Station missions and housekeeping loads is a key driver in overall Space Station design. conversely, Space Station requirements drive the power technology. Various power system technology options are discussed. The mission analysis studies resulting in the required Space Station capabilities are also discussed. An example of Space Station functions and a concept to provide them is presented. The weight, area, payload and altitude requirements on draft and mass requirements are described with a summary and status of key power systems technology requirements and issues.

  5. Space Station Power System

    NASA Technical Reports Server (NTRS)

    Baraona, C. R.

    1984-01-01

    The strategies, reasoning, and planning guidelines used in the development of the United States Space Station Program are outlined. The power required to support Space Station missions and housekeeping loads is a key driver in overall Space Station design. conversely, Space Station requirements drive the power technology. Various power system technology options are discussed. The mission analysis studies resulting in the required Space Station capabilities are also discussed. An example of Space Station functions and a concept to provide them is presented. The weight, area, payload and altitude requirements on draft and mass requirements are described with a summary and status of key power systems technology requirements and issues.

  6. Intracellular Parasite Invasion Strategies

    NASA Astrophysics Data System (ADS)

    Sibley, L. D.

    2004-04-01

    Intracellular parasites use various strategies to invade cells and to subvert cellular signaling pathways and, thus, to gain a foothold against host defenses. Efficient cell entry, ability to exploit intracellular niches, and persistence make these parasites treacherous pathogens. Most intracellular parasites gain entry via host-mediated processes, but apicomplexans use a system of adhesion-based motility called ``gliding'' to actively penetrate host cells. Actin polymerization-dependent motility facilitates parasite migration across cellular barriers, enables dissemination within tissues, and powers invasion of host cells. Efficient invasion has brought widespread success to this group, which includes Toxoplasma, Plasmodium, and Cryptosporidium.

  7. Space station power management and distribution

    NASA Technical Reports Server (NTRS)

    Teren, F.

    1985-01-01

    The power system architecture is presented by a series of schematics which illustrate the power management and distribution (PMAD) system at the component level, including converters, controllers, switchgear, rotary power transfer devices, power and data cables, remote power controllers, and load converters. Power distribution options, reference power management, and control strategy are also outlined. A summary of advanced development status and plans and an overview of system test plans are presented.

  8. Theory P: Strategies for Keeping Peace.

    ERIC Educational Resources Information Center

    Sisley, Becky L.

    1988-01-01

    Four strategies are presented which physical education department administrators should employ in their roles as people managers and peacemakers: employing effective people skills, creating trust through positioning, harmonizing objectives, and generating followership through effective use of power. (IAH)

  9. Hashing strategies for the Cray XMT.

    SciTech Connect

    Scherrer, Chad; Haglin, David; Goodman, Eric L.; Feo, John; Mogill, Jace; Chavarria-Miranda, Daniel

    2010-04-01

    Two of the most commonly used hashing strategies - linear probing and hashing with chaining - are adapted for efficient execution on a Cray XMT. These strategies are designed to minimize memory contention. Datasets that follow a power law distribution cause significant performance challenges to shared memory parallel hashing implementations. Experimental results show good scalability up to 128 processors on two power law datasets with different data types: integer and string. These implementations can be used in a wide range of applications.

  10. The Unseen Power Loss: Stemming the Flow.

    ERIC Educational Resources Information Center

    Gillett, Raphael

    2002-01-01

    Outlined an estimate-substitution strategy for a test comparing two means and developed an expected-power formula for the test. Demonstrated that for empirically representative distributions of effect size in psychology, the expected power deficit is large. (SLD)