WorldWideScience

Sample records for ac transit fuel

  1. Alameda-Contra Costa Transit District (AC Transit) Fuel Cell Transit Buses: Preliminary Evaluation Results

    Chandler, K.; Eudy, L.

    2007-03-01

    This report provides an evaluation of three prototype fuel cell-powered transit buses operating at AC Transit in Oakland, California, and six baseline diesel buses similar in design to the fuel cell buses.

  2. National Fuel Cell Bus Program: Accelerated Testing Evaluation Report and Appendices, Alameda-Contra Costa Transit District (AC Transit)

    Chandler, K.; Eudy, L.

    2009-01-01

    This is an evaluation of hydrogen fuel cell transit buses operating at AC Transit in revenue service since March 20, 2006 compared to similar diesel buses operating from the same depot. This evaluation report includes results from November 2007 through October 2008. Evaluation results include implementation experience, fueling station operation, fuel cell bus operations at Golden Gate Transit, and evaluation results at AC Transit (bus usage, availability, fuel economy, maintenance costs, and roadcalls).

  3. National Fuel Cell Bus Program: Accelerated Testing Evaluation Report #2, Alameda-Contra Costa Transit District (AC Transit) and Appendices

    Eudy, L.; Chandler, K.

    2010-06-01

    This is an evaluation of hydrogen fuel cell transit buses operating at AC Transit in revenue service since March 20, 2006, comparing similar diesel buses operating from the same depot. It covers November 2007 through February 2010. Results include implementation experience, fueling station operation, evaluation results at AC Transit (bus usage, availability, fuel economy, maintenance costs, and road calls), and a summary of achievements and challenges encountered during the demonstration.

  4. AC power generation from microbial fuel cells

    Lobo, Fernanda Leite; Wang, Heming; Forrestal, Casey; Ren, Zhiyong Jason

    2015-11-01

    Microbial fuel cells (MFCs) directly convert biodegradable substrates to electricity and carry good potential for energy-positive wastewater treatment. However, the low and direct current (DC) output from MFC is not usable for general electronics except small sensors, yet commercial DC-AC converters or inverters used in solar systems cannot be directly applied to MFCs. This study presents a new DC-AC converter system for MFCs that can generate alternating voltage in any desired frequency. Results show that AC power can be easily achieved in three different frequencies tested (1, 10, 60 Hz), and no energy storage layer such as capacitors was needed. The DC-AC converter efficiency was higher than 95% when powered by either individual MFCs or simple MFC stacks. Total harmonic distortion (THD) was used to investigate the quality of the energy, and it showed that the energy could be directly usable for linear electronic loads. This study shows that through electrical conversion MFCs can be potentially used in household electronics for decentralized off-grid communities.

  5. DC and AC biasing of a transition edge sensor microcalorimeter

    We are developing AC-biased transition edge sensor (TES) microcalorimeters for use in large arrays with frequency-domain multiplexing. Using DC bias, we have achieved a resolution of 17 eV FWHM at 2.6 keV with a decay time of 90 μs and an effective detector diameter of 300 μm. We have successfully measured thermal pulses with a TES microcalorimeter operated with an AC bias. We present here preliminary results from a single pixel detector operated under DC and AC bias conditions

  6. Stimulated Raman clock transition without a differential ac Stark

    We considered a stimulated Raman clock transition between the ground hyperfine states of an alkali atom by using the second-order perturbation theory and the spherical tensor formalism. When the light fields are circularly polarized and properly detuned, the differential ac Stark shift of the clock transition vanishes with non-vanishing transition amplitude. With a two-zone Raman Ramsey method and a slow atomic beam, the proposed scheme should result in a clock with a systematic shift of the order of a few mHz for the case of cesium. (author)

  7. Connecticut Transit (CTTRANSIT) Fuel Cell Transit Bus: Preliminary Evaluation Results

    Chandler, K.; Eudy, L.

    2008-10-01

    This report provides preliminary results from a National Renewable Energy Laboratory evaluation of a protoptye fuel cell transit bus operating at Connecticut Transit in Hartford. Included are descriptions of the planned fuel cell bus demonstration and equipment; early results and agency experience are also provided.

  8. Checklist for transition to new highway fuel(s).

    Risch, C.; Santini, D.J. (Energy Systems)

    2011-12-15

    Transportation is vital to the U.S. economy and society. As such, U.S. Presidents have repeatedly stated that the nation needs to reduce dependence on petroleum, especially for the highway transportation sector. Throughout history, highway transportation fuel transitions have been completed successfully both in United States and abroad. Other attempts have failed, as described in Appendix A: Historical Highway Fuel Transitions. Planning for a transition is critical because the changes can affect our nation's ability to compete in the world market. A transition will take many years to complete. While it is tempting to make quick decisions about the new fuel(s) of choice, it is preferable and necessary to analyze all the pertinent criteria to ensure that correct decisions are made. Doing so will reduce the number of changes in highway fuel(s). Obviously, changes may become necessary because of occurrences such as significant technology breakthroughs or major world events. With any and all of the possible transitions to new fuel(s), the total replacement of gasoline and diesel fuels is not expected. These conventional fuels are envisioned to coexist with the new fuel(s) for decades, while the revised fuel and vehicle infrastructures are implemented. The transition process must analyze the needs of the primary 'players,' which consist of the customers, the government, the fuel industry, and the automotive industry. To maximize the probability of future successes, the prime considerations of these groups must be addressed. Section 2 presents a succinct outline of the Checklist. Section 3 provides a brief discussion about the groupings on the Checklist.

  9. Effects of oxygenated fuels are questioned at ACS meeting

    The oxygenated fuels business is again under attack. A trio of scientific teams charges that atmospheric monitoring suggests reformulated gasoline is not significantly cutting carbon monoxide (CO) levels and could be raising ambient concentrations of such compounds as formaldehyde and nitrogen oxides. The results, presented at last week's meeting of the American Chemical Society (ACS) in Denver, come less than a month after heightened public concerns about the health effects of methyl tert-butyl ether (MTBE). The scientists reporting at the ACS meeting separately measured air pollution in Denver; Albuquerque, NM; and Brazil-areas that have used oxygenated fuels for several years. The preliminary results, they say, show oxygenates use has little impact on carbon monoxide. And the researchers say they have found relatively high levels of acetaldehyde, formaldehyde, and related compounds, including the mutagen peroxyacetyl nitrate (PAN), in the atmosphere. According to Daniel Grosjean, of environmental research firm DGA (Ventura, Ca), measured levels of acetaldehyde in three Brazilian cities - which began using ethanol fuels in the late 1970s - appear to be among the highest in the world. The findings could cast serious doubts on the ambitious U.S. oxygenates program, which is increasingly requiring cities to use reformulated fuels. In 1988, Denver became the first U.S. city which mandated oxygenated fuels requirements. The region now uses oxygenates-mainly MTBE-for four months each year. But, says Larry G. Anderson, a chemist at the University of Colorado (Denver), we have seen no statistical effect on CO in the air. He points to a predicted 15%-20% drop in ambient CO by 1993. There is considerable evidence formaldehyde increased, Anderson says

  10. Dynamic Analysis of Fuel Cycle Transitioning

    Dixon, B.W.; Piet, S.J.; Shropshire, D.E.; Matthern, G.E. [Idaho National Laboratory, Brent Dixon, P.O.Box 1625, Idaho Falls, Idaho 83415 (United States)

    2009-06-15

    This paper examines the time-dependent dynamics of transitioning from a once-through fuel cycle to a closed fuel cycle. The once-through system involves only Light Water Reactors (LWRs) operating on uranium oxide fuel UOX), while the closed cycle includes both LWRs and fast spectrum reactors (FRs) in either a single-tier system or two-tier fuel system. The single-tier system includes full transuranic recycle in FRs while the two-tier system adds one pass of mixed oxide uranium-plutonium (MOX U-Pu) fuel in the LWR. While the analysis primarily focuses on burner fast reactors, transuranic conversion ratios up to 1.07 are assessed and many of the findings apply to any fuel cycle transitioning from a thermal once-through system to a synergistic thermal-fast recycle system. These findings include uranium requirements for a range of nuclear electricity growth rates, the importance of back end fuel cycle facility timing and magnitude, the impact of employing a range of fast reactor conversion ratios, system sensitivity to used fuel cooling time prior to recycle, impacts on a range of waste management indicators, and projected electricity cost ranges for once-through, single-tier and two-tier systems. The paper summarizes a comprehensive study conducted in 2008 by the Systems Analysis campaign of the U. S. Department of Energy's Advanced Fuel Cycle Initiative. The study assessed a range of issues associated with the U.S. transitioning to a closed recycle system before mid-century. The study focused on the dynamic behavior of the system during the transition period, including introduction of initial fast reactors and recycle facilities, work-off of stores of used fuel and the eventual stabilization of the ratio of fast reactors to thermal reactors in a dynamic equilibrium by the end of the century. Sensitivity studies were used to increase understanding of the impact of several key assumptions. The study confirmed that significant waste management benefits can be

  11. Design and fuel fabrication processes for the AC-3 mixed-carbide irradiation test

    The AC-3 test was a cooperative U.S./Swiss irradiation test of 91 wire-wrapped helium-bonded U-20% Pu carbide fuel pins irradiated to 8.3 at % peak burnup in the Fast Flux Test Facility. The test consisted of 25 pins that contained spherepac fuel fabricated by the Paul Scherrer Institute (PSI) and 66 pins that contained pelletized fuel fabricated by the Los Alamos National Laboratory. Design of AC-3 by LANL and PSI was begun in 1981, the fuel pins were fabricated from 1983 to 1985, and the test was irradiated from 1986 to 1988. The principal objective of the AC-3 test was to compare the irradiation performance of mixed-carbide fuel pins that contained either pelletized or sphere-pac fuel at prototypic fluence and burnup levels for a fast breeder reactor

  12. Dynamic Analysis of Fuel Cycle Transitioning

    Brent Dixon; Steve Piet; David Shropshire; Gretchen Matthern

    2009-09-01

    This paper examines the time-dependent dynamics of transitioning from a once-through fuel cycle to a closed fuel cycle. The once-through system involves only Light Water Reactors (LWRs) operating on uranium oxide fuel UOX), while the closed cycle includes both LWRs and fast spectrum reactors (FRs) in either a single-tier system or two-tier fuel system. The single-tier system includes full transuranic recycle in FRs while the two-tier system adds one pass of mixed oxide uranium-plutonium (MOX U-Pu) fuel in the LWR. While the analysis primarily focuses on burner fast reactors, transuranic conversion ratios up to 1.0 are assessed and many of the findings apply to any fuel cycle transitioning from a thermal once-through system to a synergistic thermal-fast recycle system. These findings include uranium requirements for a range of nuclear electricity growth rates, the importance of back end fuel cycle facility timing and magnitude, the impact of employing a range of fast reactor conversion ratios, system sensitivity to used fuel cooling time prior to recycle, impacts on a range of waste management indicators, and projected electricity cost ranges for once-through, single-tier and two-tier systems. The study confirmed that significant waste management benefits can be realized as soon as recycling is initiated, but natural uranium savings are minimal in this century. The use of MOX in LWRs decouples the development of recycle facilities from fast reactor fielding, but also significantly delays and limits fast reactor deployment. In all cases, fast reactor deployment was significantly below than predicted by static equilibrium analyses.

  13. Transition Towards a Sustainable Nuclear Fuel Cycle

    To support the evaluation of R and D needs and relevant technology requirements for future nuclear fuel cycles, the OECD/NEA WPFC Expert Group on Advanced Fuel Cycle Scenarios was created in 2010, replacing the WPFC Expert Group on Fuel Cycle Transition Scenario Studies (1) to assemble, organise and understand the scientific issues of advanced fuel cycles and (2) to provide a framework for assessing specific national needs related to the implementation of advanced fuel cycles. In this framework, a simulation of world transition scenarios towards possible future fuel cycles with fast reactors has been performed, using both a homogeneous and a heterogeneous approach involving different world regions. In fact, it has been found that a crucial feature of any world scenario study is to provide not only trends for an idealised 'homogeneous' description of the world, but also trends for different regions in the world, selected with simple criteria (mostly of geographical type), in order to apply different hypotheses to energy demand growth, different fuel cycle strategies and different reactor types implementation in the different regions. This approach was an attempt to avoid focusing on selected countries, in particular on those where no new spectacular energy demand growth is expected, but to provide trends and conclusions that account for the features of countries that will be major future players in the world's energy development. The heterogeneous approach considered a subdivision of the world in four main macro-regions (where countries have been grouped together according to their economic development dynamics). An original global electricity production envelope was used in simulations and a specific regional energy share was defined. In the regional approach two different fuel cycles were analysed: a once-through LWR cycle was used as the reference and a transition to fast reactor closed cycle to enable a better management of resources and minimisation of waste

  14. Fuel Cell Buses in U.S. Transit Fleets: Current Status 2015

    Eudy, Leslie [National Renewable Energy Lab. (NREL), Golden, CO (United States); Post, Matthew [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gikakis, Christina [Federal Transit Administration, Washington, DC (United States)

    2015-12-11

    This report, published annually, summarizes the progress of fuel cell electric bus (FCEB) development in the United States and discusses the achievements and challenges of introducing fuel cell propulsion in transit. Various stakeholders, including FCEB developers, transit agencies, and system integrators, have expressed the value of this annual status report, which provides a summary of results from evaluations performed by the National Renewable Energy Laboratory. The annual status report tracks the progress of the FCEB industry toward meeting technical targets, documents the lessons learned, and discusses the path forward for commercial viability of fuel cell technology for transit buses. The 2015 summary results primarily focus on the most recent year for each demonstration, from August 2014 through July 2015. The results for these buses account for more than 1,045,000 miles traveled and 83,000 hours of fuel cell power system operation. The primary results presented in the report are from two demonstrations of fuel-cell-dominant bus designs: the Zero Emission Bay Area Demonstration Group led by Alameda-Contra Costa Transit District (AC Transit) in California and the American Fuel Cell Bus Project at SunLine Transit Agency in California.

  15. Fuel Cell Buses in U.S. Transit Fleets: Current Status 2010

    Eudy, L.; Chandler, K.; Gigakis, C.

    2010-11-01

    This status report, fourth in a series of annual status reports from the U.S. Department of Energy's National Renewable Energy Laboratory, summarizes progress and accomplishments from demonstrations of fuel cell transit buses in the United States. This year's assessment report provides the results from the fifth year of operation of five Van Hool, ISE, and UTC Power fuel cell buses operating at AC Transit, SunLine, and CTTRANSIT. The achievements and challenges of this bus design, implementation, and operating are presented, with a focus on the next steps for implementing larger numbers and new and different designs of fuel cell buses. The major positive result from nearly five years of operation is the dramatic increase in reliability experienced for the fuel cell power system.

  16. Calculation of transition probabilities and ac Stark shifts in two-photon laser transitions of antiprotonic helium

    HORI, MASAKI; Korobov, Vladimir I.

    2010-01-01

    Numerical ab initio variational calculations of the transition probabilities and ac Stark shifts in two-photon transitions of antiprotonic helium atoms driven by two counter-propagating laser beams are presented. We found that sub-Doppler spectroscopy is in principle possible by exciting transitions of the type (n,L)->(n-2,L-2) between antiprotonic states of principal and angular momentum quantum numbers n~L-1~35, first by using highly monochromatic, nanosecond laser beams of intensities 10^4...

  17. Core and transition fuel assembly for a nuclear reactor

    A core and a transition fuel assembly for a nuclear reactor are described. They have a first fuel assembly including structure for laterally spacing parallel and coextending fuel rods positioned at preselected core elevations and also a second fuel assembly including lateral spacing structure at preselected core elevations at least one of which is different than the elevations of the spacing structure of the first fuel assembly. The transition fuel assembly is positioned between the first and second assemblies and includes lateral spacing structure positioned at each core elevation where the first and second fuel assemblies have a spacing structure. The transition fuel assembly ensures that contact among the fuel assemblies of the core is through the spacing structures. 9 claims

  18. Calculation of transition probabilities and ac Stark shifts in two-photon laser transitions of antiprotonic helium

    Numerical ab initio variational calculations of the transition probabilities and ac Stark shifts in two-photon transitions of antiprotonic helium atoms driven by two counter-propagating laser beams are presented. We found that sub-Doppler spectroscopy is, in principle, possible by exciting transitions of the type (n,L)→(n-2,L-2) between antiprotonic states of principal and angular momentum quantum numbers n∼L-1∼35, first by using highly monochromatic, nanosecond laser beams of intensities 104-105 W/cm2, and then by tuning the virtual intermediate state close (e.g., within 10-20 GHz) to the real state (n-1,L-1) to enhance the nonlinear transition probability. We expect that ac Stark shifts of a few MHz or more will become an important source of systematic error at fractional precisions of better than a few parts in 109. These shifts can, in principle, be minimized and even canceled by selecting an optimum combination of laser intensities and frequencies. We simulated the resonance profiles of some two-photon transitions in the regions n=30-40 of the p4He+ and p3He+ isotopes to find the best conditions that would allow this.

  19. An overview of power electronics applications in fuel cell systems: DC and AC converters.

    Ali, M S; Kamarudin, S K; Masdar, M S; Mohamed, A

    2014-01-01

    Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter. PMID:25478581

  20. Non-linear response of ac conductivity in narrow YBCO film strips at the superconducting transition

    Measurements of higher harmonics of the ac voltage response in YBCO thin film strips under low amplitude and low frequency harmonic excitation, as a function of temperature, show a non linear response of the conductivity in the superconducting transition interval. The third and fifth harmonics of the local voltage as a function of T exhibit a peak near Tc and their amplitudes seem to be closely related to the T-derivative of the first harmonic. The peaks are linearly dependent on the current amplitude and do not depend on frequency. The observed data are partially interpreted in terms of ac current induced thermal modulation of the sample temperature added to strong thermally activated fluctuations in the transition region. The fit of the model to the data gives information of some sample properties such as zero temperature critical current, zero onset resistance and thermal boundary conductance

  1. Benchmark Study on Nuclear Fuel Cycle Transition Scenarios - Analysis Codes

    Under the auspices of the NEA Nuclear Science Committee (NSC), the Working Party on Scientific Issues of the Fuel Cycle (WPFC) has been established to co-ordinate scientific activities regarding various existing and advanced nuclear fuel cycles, including advanced reactor systems, associated chemistry and flowsheets, development and performance of fuel and materials, accelerators and spallation targets. The WPFC has different expert groups to cover a wide range of scientific fields in the nuclear fuel cycle. The Expert Group on Fuel Cycle Transition Scenarios Studies was created in 2003 to study R and D needs and relevant technology for an efficient transition from current to future advanced reactor fuel cycles. The objectives of the expert group are to (1) assemble and organise institutional, technical, and economics information critical to the understanding of the issues involved in transitioning from current fuel cycles to long-term sustainable fuel cycles or a phase-out of the nuclear enterprise and (2) provide a framework for assessing specific national needs related to that transition. After reviewing national, regional or worldwide transition scenarios, the expert group performed a benchmark study to compare the existing codes in terms of capabilities, modelling and results. The benchmark was conducted in two phases: (1) depletion calculations for PWR UOX, PWR MOX and fast reactor calculations and (2) transition calculation using various scenario codes (COSI, FAMILY21, VISION, EVOLCODE and DESAE) using three different transition scenarios (once-through, limited plutonium recycling in LWRs and plutonium and minor actinides recycling in fast reactors). The comparison mainly focused on the mass flow and the composition of heavy elements depending on time, i.e. natural uranium needs, enrichment needs, fresh fuel fabrication needs, fuel irradiation, inventory of spent fuel and nuclear materials, reprocessing needs, etc

  2. Metal-to-insulator transition in thin-film polymeric AC60

    We present an electron spectroscopy study of phase-pure AC60 thin films (A= Rb, Cs) in their monomer (face-centred cubic (fcc)) and polymer phases. A surface electronic reconstruction is observed in polymeric RbC60, analogous to that reported for the fcc phase. As for pristine C60, the occupied electronic states of AC60 fullerides are not dramatically affected by polymerization. The energy separation between the leading feature in photoemission and inverse photoemission is similar in both stable AC60 phases. These observations suggest that electron correlation effects are similar in the two phases, and that their different electronic behaviour is mainly related to the reduction of degeneracy of the polymer frontier states. Photoemission and electron-energy loss spectroscopy data show that the thin-film form of the RbC60 polymer is metallic at room temperature, and that it undergoes a metal-insulator transition at around 100 K. This transition temperature is much higher than that reported for the corresponding bulk phase and signals a poorer screening of Coulomb interactions at the film surface.

  3. Fuel cycle transition - A Belgian implementation scenario

    At the end of 2002 the total installed electric power in Belgium was 16,200 MWe of which 40% (6485 MWe) corresponds to the seven nuclear power plants installed on the two Belgian sites of Doel (4 power plants) and Tihange (3 power plants) and the 25% participation in the two French Units B1 and B2 at Chooz at the Belgian-French border. The nuclear installed power in Belgium is 5800 MWe. In 2003, the government decided to phase out the nuclear energy progressively by closing the Belgian NPPs after 40 years of operation. This means that the first generation units (Doel 1, Doel 2 and Tihange 1) will be closed in 2015 and the four other remaining units in 2022-2025. Nevertheless, this phase out is subject to various conditions: the guarantee of energy independence should not be affected and the engagement to respect the Kyoto agreement (reducing the CO2 production by 7.5% in 2010 as compared to the 1990 production). Thus the phase-out decision can be re-opened if the above mentioned conditions are not met. The paper has the following contents: 1. Introduction; 2. Actual fuel cycle; 3. Transition fuel cycle; 4. Calculations; 4.1. PWR modelling; 4.2. ADS modelling; 4.3. Calculation code; 5. Results; 5.1. PWR/EPR; 5.2. ADS; 6. Conclusions. In conclusion it is shown that the evaluated stock pile of waste in Belgium (with no increase of electricity demand) coming from the thermal reactors park is 4380 tons (52 t Pu, 9 t MA, 217 t FP) with phase out (i.e. between 1975, first PWR and 2025, last PWR) and 7825 tons (84 t Pu, 20 t MA, 381 t FP) without phase out (i.e. between 1975, first PWR and 2075, last EPR). According to this study, Belgium should keep all its first generation Pu for the eventual starting of the self burning FR. Indeed, the Pu needed to start the self burning FR is evaluated between 60 t and 90 t (based on 10 t to 15 t per GWe). With an homogeneous core loading, 54% of the MA could be eliminated after 24 years in three 600 MWth industrial ADS (corresponding

  4. BC Transit Fuel Cell Bus Project: Evaluation Results Report

    Eudy, L.; Post, M.

    2014-02-01

    This report evaluates a fuel cell electric bus demonstration led by British Columbia Transit (BC Transit) in Whistler, Canada. BC Transit is collaborating with the California Air Resources Board and the U.S. Department of Energy's National Renewable Energy Laboratory to evaluate the buses in revenue service. This evaluation report covers two years of revenue service data on the buses from April 2011 through March 2013.

  5. Nuclear fuel cycles of WWER-1000 at Kozloduy NPP: a program for transition to advanced fuel

    A systematical approach for WWER nuclear fuel utilization improvement is applied at the Kozloduy NPP while observing safety requirements. The fuel assemblies utilization for 4 years, higher burnup and reducing of high-activity radioactive waste will be achieved by realization of Activities program for transition of Units 5 and 6 of Kozloduy NPP to operating with Alternative Fuel Assemblies (AFA). The specified results from advanced fuel introduction also will improve the economic indices of Units 5 and 6 operation at Kozloduy NPP

  6. DC Smart Grid Connected with Fuel Charging Station and AC Load by Hybrid MLI

    Naveen Kumar

    2013-07-01

    Full Text Available This paper presents the Solar (photo voltaic power Plant and Windmill plant with DC Smart Grid connected with an DC Fuel Charging Station For Electric Vehicle (EV, Plug in Hybrid Electric Vehicle (PHEV and converted to AC load for Consumer single or Three phase ac load by means of Hybrid Multilevel Inverter (MLI. Solar Energy which store energy in lithium-ion battery and connected to Smart Grid .Wind Energy which get stored in Lithium-ion battery that Fixed DC Voltage connected with DC Smart Grid. Smart Grid which are Connected with DC Fuel Charging Station in Ring Topology with a certain distance for charging of Electric Vehicle (EV and Plug-in Hybrid Electric Vehicle with On-Board (Integrated Charger for faster charging of EV. In Power demand for Consumer the DC load from smart grid converted into an ac load by Hybrid Multilevel Inverter. In Consumers Place the small wind mill and PV panel are installed that energy can be used for consumers load at peak time or power Shutdown .Other than the power shutdown or peak time in the consumers place, stored DC Energy can be fed to Smart Grid. A major development in distribution automation is deployment of smart meters as a gateway between the utility and customer. With such capabilities the smart meter becomes not only a point of measurement of consumed kWh but also a controller capable of bidirectional communications with both the customer and utility.

  7. Fuel Cell Buses in U.S. Transit Fleets: Current Status 2009

    Eudy, L.; Chandler, K.; Gikakis, C.

    2009-10-01

    This report documents progress in meeting the technological challenges of fuel cell propulsion for transportation based on current fuel cell transit bus demonstrations and plans for more fuel cell transit buses and hydrogen infrastructure.

  8. Core analysis during transition from 37-element fuel to CANFLEX-NU fuel in CANDU 6

    Jeong, Chang Joon; Suk, Ho Chun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    An 1200-day time-dependent fuel-management for the transition from 37-element fuel to CANFLEX-NU fuel in a CANDU 6 reactor has been simulated to show the compatibility of the CANFLEX-NU fuel with the reactor operation. The simulation calculations were carried out with the RFSP code, provided by cell averaged fuel properties obtained from the POWDERPUFS-V code. The refueling scheme for both fuels was an eight bundle shift at a time. The simulation results show that the maximum channel and bundle powers were maintained below the license limit of the CANDU 6. This indicates that the CANFLEX-NU fuel bundle is compatible with the CANDU 6 reactor operation during the transition period. 3 refs., 2 figs., 1 tab. (Author)

  9. Modeling a reversible solid oxide fuel cell as a storage device within AC power networks

    Ren, J.; Roscoe, A.J.; Burt, G. [Department of Electronic and Electrical Engineering, Royal College, University of Strathclyde, Glasgow (United Kingdom); Gamble, S.R.; Irvine, J.T.S. [School of Chemistry, University of St. Andrews, Purdie Building, St. Andrews (United Kingdom)

    2012-10-15

    A reversible solid oxide fuel cell (RSOFC) system, consisting of a RSOFC stack, heat store, and electrical inverters to convert DC to AC power, is shown by computer modeling to have the potential to efficiently store electrical energy. This paper describes the modeling of a single RSOFC, based on a proposed cell geometry, empirical data on the resistivities of the components, and calculation of activation and diffusion polarization resistances from electrochemical theory. Data from ac impedance spectroscopy measurements on symmetrical cells are used to model RSOFC impedance. A RSOFC stack is modeled by electrically linking the individual cells inside a pressurized vessel. A phase change heat store is added to improve energy storage efficiency. The model is implemented in MATLAB {sup registered} /Simulink {sup registered}. Two competing inverter control schemes are compared, trading off DC bus ripple against AC power quality. It is found that selection of appropriate DC bus capacitance is important in certain scenarios, with potential system cost implications. It is shown that the system can store electrical energy at an efficiency of 64% over a single discharge-charge cycle, i.e., hydrogen to electricity and heat to hydrogen. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Connecticut Transit (CTTRANSIT) Fuel Cell Transit Bus: Third Evaluation Report and Appendices

    Chandler, K.; Eudy, L.

    2010-01-01

    This report describes operations at Connecticut Transit (CTTRANSIT) in Hartford for one prototype fuel cell bus and three new diesel buses operating from the same location. The prototype fuel cell bus was manufactured by Van Hool and ISE Corp. and features an electric hybrid drive system with a UTC Power PureMotion 120 Fuel Cell Power System and ZEBRA batteries for energy storage. The fuel cell bus started operation in April 2007, and evaluation results through October 2009 are provided in this report.

  11. Stick-Slip to Sliding Transition of Dynamic Contact Lines under AC Electrowetting.

    't Mannetje, D J C M; Mugele, F; van den Ende, D

    2013-12-01

    We show that at low velocities the dynamics of a contact line of a water drop moving over a Teflon-like surface under ac electrowetting must be described as stick-slip motion, rather than one continuous movement. At high velocities we observe a transition to a slipping regime. In the slipping regime the observed dependence of the contact angle is well described by a linearization of both the hydrodynamic and the molecular-kinetic model for the dynamic contact line behavior. The overall geometry of the drop also has a strong influence on the contact angle: if the drop is confined to a disk-like shape with radius R, much larger than the capillary length, and height h, smaller than the capillary length, the advancing angle increases steeper with velocity as the aspect ratio h/R is smaller. Although influence of the flow field near a contact line on the contact angle behavior has also been observed in other experiments, these observations do not fit either model. Finally, in our ac experiments no sudden increase of the hysteresis beyond a certain voltage and velocity was observed, as reported by other authors for a dc voltage, but instead we find with increasing voltage a steady decrease of the hysteresis. PMID:24219094

  12. BC Transit Fuel Cell Bus Project Evaluation Results: Second Report

    Eudy, L.; Post, M.

    2014-09-01

    Second report evaluating a fuel cell electric bus (FCEB) demonstration led by British Columbia Transit (BC Transit) in Whistler, Canada. BC Transit is collaborating with the California Air Resources Board and the U.S. Department of Energy's National Renewable Energy Laboratory to evaluate the buses in revenue service. NREL published its first report on the demonstration in February 2014. This report is an update to the previous report; it covers 3 full years of revenue service data on the buses from April 2011 through March 2014 and focuses on the final experiences and lessons learned.

  13. Transition cycle fuel management problems of NPP Krsko

    Transition cycle fuel management problems are described and illustrated using results and experience attained during core reload design of NPP Krsko. Improved version of computer code package PSU-LEOPARD/Mcrac is successfully applied to NPP Krsko loading pattern design. (author)

  14. Speeding the transition: Designing a fuel-cell hypercar

    Williams, B.D.; Moore, T.C.; Lovins, A.B. [Rocky Mountain Inst., Snowmass, CO (United States). Hypercar Center

    1997-12-31

    A rapid transformation now underway in automotive technology could accelerate the transition to transportation powered by fuel cells. Ultralight, advanced-composite, low-drag, hybrid-electric hypercars--using combustion engines--could be three- to fourfold more efficient and one or two orders of magnitude cleaner than today`s cars, yet equally safe, sporty, desirable, and (probably) affordable. Further, important manufacturing advantages--including low tooling and equipment costs, greater mechanical simplicity, autobody parts consolidation, shorter product cycles, and reduced assembly effort and space--permit a free-market commercialization strategy. This paper discusses a conceptual hypercar powered by a proton-exchange-membrane fuel cell (PEMFC). It outlines the implications of platform physics and component selection for the vehicle`s mass budget and performance. The high fuel-to-traction conversion efficiency of the hypercar platform could help automakers overcome the Achilles` heel of hydrogen-powered vehicles: onboard storage. Moreover, because hypercars would require significantly less tractive power, and even less fuel-cell power, they could adopt fuel cells earlier, before fuel cells` specific cost, mass, and volume have fully matured. In the meantime, commercialization in buildings can help prepare fuel cells for hypercars. The promising performance of hydrogen-fueled PEMFC hypercars suggests important opportunities in infrastructure development for direct-hydrogen vehicles.

  15. Dysprosia doped uranium dioxide fuel and the Lambda transition

    Thermodynamic properties of solid and liquid UO2, at temperatures above 2500 K, are rare and difficult to interpret. Low Void Reactivity Fuel (LVRF) employs Dysprosia in the originally natural Uranium fuel, but sufficient knowledge of solubility at all temperatures is still deficient. This paper describes research into the physical chemistry of UO2-Dy2O3 mixtures, and includes an assessment of Dy2O3 effects on UO2 at high temperatures. Specifically, research was conducted on the Lambda transition occurring at approximately 2670 K. The crystal structure determined by neutron diffraction and its effect on thermodynamic properties is discussed. (author)

  16. Leveraging Fuel Subsidy Reform for Transition in Yemen

    Olivier Ecker

    2012-10-01

    Full Text Available Yemen is currently undergoing a major political transition, yet many economic challenges—including fuel subsidy reform—remain highly relevant. To inform the transition process with respect to a potential subsidy reform, we use a dynamic computable general equilibrium and microsimulation model for Yemen; we show that overall growth effects of subsidy reduction are positive in general, but poverty can increase or decrease depending on reform design. A promising strategy for a successful reform combines fuel subsidy reduction with direct income transfers to the poorest one-third of households during reform, and productivity-enhancing investment in infrastructure, plus fiscal consolidation. Public investments should be used for integrating economic spaces and restructuring of agricultural, industrial and service value chains in order to create a framework that encourages private-sector-led and job-creating growth.

  17. Connecticut Transit (CTTRANSIT) Fuel Cell Transit Bus: Second Evaluation Report and Appendices

    Chandler, K.; Eudy, L.

    2009-05-01

    This report describes operations at Connecticut Transit (CTTRANSIT) in Hartford for one prototype fuel cell bus and three new diesel buses operating from the same location. The evaluation period in this report (January 2008 through February 2009) has been chosen to coincide with a UTC Power propulsion system changeout that occurred on January 15, 2008.

  18. Transition to integrated safeguards at nuclear fuel fabrication plants

    Full-text: This paper presents the improvements in efficiency and effectiveness of the safeguards approach applied at depleted, natural and low enriched uranium (DNLEU) conversion and fuel fabrication plants (FFPs) following a transition from traditional safeguards (TS) to integrated safeguards1 (IS). The paper will explain the relationship between the Agency drawing a broader conclusion for a State and the implementation of IS, highlight how the transition from TS to IS can be accomplished, and describe a process by which IS can be introduced through a combination of good IAEA-National Authority cooperation and field trials. For demonstration purposes, a comparison of the onsite safeguards activities before and after the introduction of IS at a fuel fabrication plant which manufactures both PWR (Pressurized Water Reactors) fuel assemblies and CANDU fuel bundles will be examined. It is expected that this will provide a good reference baseline on the safeguards improvements made possible by the introduction of IS at fuel fabrication facilities without mixed oxide fuels (MOX). The paper will also show the operational and logistical differences between the TS and IS regimes and highlight some of the advantages to a State for which a broader conclusion has been drawn by the Agency. The paper will offer technical insight to safeguards coverage of nuclear material borrowing scenarios and implementation of other safeguards measures such as the introduction of short notice random inspections (SNRI), use of a secure mailbox system at the FFP, and implementation of random interim inspections (RIIs) at LWRs (Light Water Reactors) and CANDU power reactors. (author)

  19. Dielectric permittivity, ac conductivity and phase transition in hydroxyl ammonium sulfate

    Abdel Kader, M M; Aboud, A I; Abdelmonem, H [Department of Physics, Faculty of Science, Cairo University (Egypt); Elzayat, M Y [Department of Physics, Faculty of Science, Fayoum University (Egypt); Hammad, T R, E-mail: mmahmodakader@yahoo.com [Department of Physics, Faculty of Science, Helwan University (Egypt)

    2011-03-15

    The complex dielectric permittivity ({epsilon}*={epsilon}'-j{epsilon}'') and ac conductivity {sigma} ({omega}, T) as a function of temperature (90-375 K) and frequency (0.4 kHz to {approx}100 kHz) were measured in this work for polycrystalline samples of hydroxyl ammonium sulfate, (NH{sub 3}OH){sub 2}SO{sub 4}. The measured electrical parameters revealed the existence of a structural phase transition at T{approx}312 K, which was further confirmed by a differential thermal analysis thermogram, where a clear endothermic peak centered at {approx}312 K is observed. Regarding the charge transport mechanism, it is likely that the behavior of frequency-dependent conductivity follows the universal dynamic response {sigma} ({omega},T)=A(T) {omega}{sup s(T)}. Moreover, the temperature dependence of the frequency exponent s (0{<=}s{<=}1) suggests the quantum mechanical tunneling model to be the most likely one that describes the electrical transport mechanism. The data correlate with the crystal structure and the hydrogen-bonding system.

  20. Spin density wave (SDW) transition in Ru doped BaFeAs2 investigated by AC steady state calorimetry

    Heat capacity measurements were done on sub-micron sized BaFe2−xRuxAs2 single crystals using thin film membrane based the AC steady state calorimetry technique. Noticeable thermal hysteresis is observed in the heat capacity of the BaFe2−xRuxAs2 during cooling and warming cycles, indicating first order nature of the SDW transition

  1. Safety evaluation of a hydrogen fueled transit bus

    Coutts, D.A.; Thomas, J.K.; Hovis, G.L.; Wu, T.T. [Westinghouse Savannah River Co., Aiken, SC (United States)

    1997-12-31

    Hydrogen fueled vehicle demonstration projects must satisfy management and regulator safety expectations. This is often accomplished using hazard and safety analyses. Such an analysis has been completed to evaluate the safety of the H2Fuel bus to be operated in Augusta, Georgia. The evaluation methods and criteria used reflect the Department of Energy`s graded approach for qualifying and documenting nuclear and chemical facility safety. The work focused on the storage and distribution of hydrogen as the bus motor fuel with emphases on the technical and operational aspects of using metal hydride beds to store hydrogen. The safety evaluation demonstrated that the operation of the H2Fuel bus represents a moderate risk. This is the same risk level determined for operation of conventionally powered transit buses in the United States. By the same criteria, private passenger automobile travel in the United States is considered a high risk. The evaluation also identified several design and operational modifications that resulted in improved safety, operability, and reliability. The hazard assessment methodology used in this project has widespread applicability to other innovative operations and systems, and the techniques can serve as a template for other similar projects.

  2. Reducing transit bus emissions: Alternative fuels or traffic operations?

    Alam, Ahsan; Hatzopoulou, Marianne

    2014-06-01

    In this study, we simulated the operations and greenhouse gas (GHG) emissions of transit buses along a busy corridor and quantified the effects of two different fuels (conventional diesel and compressed natural gas) as well as a set of driving conditions on emissions. Results indicate that compressed natural gas (CNG) reduces GHG emissions by 8-12% compared to conventional diesel, this reduction could increase to 16% with high levels of traffic congestion. However, the benefits of switching from conventional diesel to CNG are less apparent when the road network is uncongested. We also investigated the effects of bus operations on emissions by applying several strategies such as transit signal priority (TSP), queue jumper lanes, and relocation of bus stops. Results show that in congested conditions, TSP alone can reduce GHG emissions by 14% and when combined with improved technology; a reduction of 23% is achieved. The reduction benefits are even more apparent when other transit operational improvements are combined with TSP. Finally a sensitivity analysis was performed to investigate the effect of operational improvements on emissions under varying levels of network congestion. We observe that under “extreme congestion”, the benefits of TSP decrease.

  3. Prediction of temperature and water level in a spent fuel pit during loss of all AC power supplies

    A prediction method for water temperature in a spent fuel pit of a pressurized water reactor (PWR) has been developed to calculate the increase in water temperature during the shutdown of cooling systems. In this study, the prediction method was extended to calculate the water level in a spent fuel pit during loss of all AC power supplies, and predicted results were compared with measured values of spent fuel pools in the Fukushima Daiichi Nuclear Power Station. The calculations gave reasonable results, but overestimated the decreasing rate of the water level and the water temperature. This indicated that decay heat was overestimated and evaporation heat transfer from the water surface was underestimated. Results of calculations with 80% decay heat and 155% (Unit 4 pool) or 230% (Unit 2 pool) evaporation heat flux were in good agreement with measured values. The data-fitted evaporation heat fluxes agreed rather well with the evaporation heat transfer correlation proposed by Fujii et al. (author)

  4. Prediction of temperature and water level in a spent fuel pit during loss of all AC powers

    A prediction method for water temperature in a spent fuel pit of a PWR has been developed to calculate the increase in water temperature during the shutdown of cooling systems. In this study, the prediction method was extended to calculate the water level in a spent fuel pit during loss of all AC powers, and predicted results were compared with data of spent fuel pools in the Fukushima Daiichi Nuclear Power Station. The calculations gave reasonable results, but overestimated the decreasing rate of the water level and water temperature. This result indicated that decay heat was overestimated and evaporation heat transfer from the water surface was underestimated. Results of calculations with 80% decay heat and 155% (No. 4 pool) or 230% (No. 2 pool) evaporation heat flux were in good agreement with data. The data-fitted evaporation heat fluxes agreed rather well with the evaporation heat transfer correlation proposed by Fujii et al. (author)

  5. Fuel Cell Buses in U.S. Transit Fleets: Current Status 2013

    Eudy, L.; Gikakis, C.

    2013-12-01

    This report is the seventh in an annual series of reports that summarize the progress of fuel cell electric bus (FCEB) development in the United States and discuss the achievements and challenges of introducing fuel cell propulsion in transit. The report also provides a snapshot of current FCEB performance results from August 2012 through July 2013 for five FCEB demonstrations at four transit agencies.

  6. ac Stark shift measurements of the clock transition in cold Cs atoms: Scalar and tensor light shifts of the D2 transition

    Costanzo, G. A.; Micalizio, S.; Godone, A.; Camparo, J. C.; Levi, F.

    2016-06-01

    The ac Stark shift, or light shift, is a physical phenomenon that plays a fundamental role in many applications ranging from basic atomic physics to applied quantum electronics. Here, we discuss experiments testing light-shift theory in a cold-atom cesium fountain clock for the Cs D2 transition (i.e., 6 2S1 /2→6 2P3 /2 at 852 nm). Cold-atom fountains represent a nearly ideal system for the study of light shifts: (1) The atoms can be perturbed by a field of arbitrary character (e.g., coherent field or nonclassical field); (2) there are no trapping fields to complicate data interpretation; (3) the probed atoms are essentially motionless in their center-of-mass reference frame, T ˜ 1 μK; and (4) the atoms are in an essentially collisionless environment. Moreover, in the present work the resolution of the Cs excited-state hyperfine splittings implies that the D2 ac Stark shift contains a nonzero tensor polarizability contribution, which does not appear in vapor phase experiments due to Doppler broadening. Here, we test the linearity of the ac Stark shift with field intensity, and measure the light shift as a function of field frequency, generating a "light-shift curve." We have improved on the previous best test of theory by a factor of 2, and after subtracting the theoretical scalar light shift from the experimental light-shift curves, we have isolated and tested the tensor light shift for an alkali D2 transition.

  7. New aspects in the Bragg Glass-Disordered phase transition: an analysis based on the 3rd harmonics of the AC magnetic susceptibility

    Adesso*, M. G.; Flukiger, R.; Giamarchi, T.; Goldacker, W.; H.; Kupfer; Pace, S.; Polichetti, M.; Uglietti, D.

    2007-01-01

    We analyse the phase transition between the Bragg Glass and the Disordered phase in the vortex lattice in type-II superconductors, both by analytical computations and experimental investigations. It is known that if the Peak Effect can be detected, a Bragg Glass/Disordered phase transition takes place. We show that, in some conditions, this transition can occur without the observation of the Peak Effect Phenomenon. We introduce a method based on the 3rd harmonics of the AC magnetic susceptibi...

  8. Transition Analysis of Promising U.S. Future Fuel Cycles Using ORION

    Sunny, Eva E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Worrall, Andrew [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Peterson, Joshua L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Powers, Jeffrey J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gehin, Jess C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gregg, Robert [Preston Laboratory, Springfields Works (United Kingdom)

    2015-01-01

    The US Department of Energy Office of Fuel Cycle Technologies performed an evaluation and screening (E&S) study of nuclear fuel cycle options to help prioritize future research and development decisions. Previous work for this E&S study focused on establishing equilibrium conditions for analysis examples of 40 nuclear fuel cycle evaluation groups (EGs) and evaluating their performance according to a set of 22 standardized metrics. Following the E&S study, additional studies are being conducted to assess transitioning from the current US fuel cycle to future fuel cycle options identified by the E&S study as being most promising. These studies help inform decisions on how to effectively achieve full transition, estimate the length of time needed to undergo transition from the current fuel cycle, and evaluate performance of nuclear systems and facilities in place during the transition. These studies also help identify any barriers to achieve transition. Oak Ridge National Laboratory (ORNL) Fuel Cycle Options Campaign team used ORION to analyze the transition pathway from the existing US nuclear fuel cycle—the once-through use of low-enriched-uranium (LEU) fuel in thermal-spectrum light water reactors (LWRs) —to a new fuel cycle with continuous recycling of plutonium and uranium in sodium fast reactors (SFRs). This paper discusses the analysis of the transition from an LWR to an SFR fleet using ORION, highlights the role of lifetime extensions of existing LWRs to aid transition, and discusses how a slight delay in SFR deployment can actually reduce the time to achieve an equilibrium fuel cycle.

  9. Thermal-Hydraulic Design of Mixed Transition Core for FCM Fuel Assembly

    Kwon, Hyuk; Seo, K. W; Kim, S. J.; Park, J. P; Hwang, D. H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, W. J [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    A fully ceramic micro-encapsulated(FCM) fuel based on the dispersed particle fuel concept was considered on the one of accident tolerant fuel(ATF). A mixed core is established using the FCM fuel in the existing LWR core where UO2 fuel pellet was loaded. In order to demonstrate the thermal-hydraulic compatibility of the FCM fuel in the existing LWR core, pin by pin analysis is performed for transition period from mixed core with FCM fuel and UO2 fuel to the FCM fuel only. Parallelized MATRA code using MPI is developed for pin by pin calculation. Pin by pin analysis on mixed transition core for FCM fuel and reference UO2 fuel was performed on a quarter core with 13310 subchannels in assistance with the parallel algorithm with MPI with 20 cores. The thermal margin for the pin by pin model was evaluated by employing a quarter-core power distribution data provided by MASTER code that is nodal code. The pin by pin model shows the feasibility of mixed transition core of FCM fuel assembly based on the MDNBR results.

  10. Dual role of an ac driving force and the underlying two distinct order–disorder transitions in the vortex phase diagram of Ca3Ir4Sn13

    Highlights: • This work pertains to new findings related to a broad SMP anomaly. • Broad SMP prima facie encompasses two phase transformations in vortex matter. • We demarcated two phase boundaries pertaining to order–disorder transitions which have quasi first-order nature. - Abstract: We present distinct demarcation of the Bragg glass (BG) to multi-domain vortex glass (VG) transition line and the eventual amorphization of the VG phase in a weakly pinned single crystal of the superconducting compound Ca3Ir4Sn13 on the basis of comprehension of the different yields about the second magnetization peak (SMP) anomaly in the dc magnetization and the corresponding anomalous feature in the ac susceptibility measurements. The shaking by a small ac magnetic field, inevitably present in the ac susceptibility measurements, is seen to result in contrasting responses in two different portions of the field-temperature (H, T) phase space of the multi-domain VG. In one of the portions, embracing the BG to VG transition across the onset of the SMP anomaly, the ac drive is surprisingly seen to assist the transformation of the well ordered BG phase to a lesser ordered VG phase. The BG phase exists as a superheated state over a small portion of the VG space and this attests to the first order nature of the BG to VG transition

  11. Bay Area Transit Agencies Propel Fuel Cell Buses Toward Commercialization (Fact Sheet)

    2010-07-01

    This fact sheet describes the Zero Emission Bay Area (ZEBA) demonstration of the next generation of fuel cells buses. Several transit agencies in the San Francisco Bay Area are participating in demonstrating the largest single fleet of fuel cell buses in the United States.

  12. Fuel Cell Buses in U.S. Transit Fleets: Current Status 2012

    Eudy, Leslie [National Renewable Energy Lab. (NREL), Golden, CO (United States); Chandler, Kevin [Battelle, Columbus, OH (United States); Gikakis, Christina [Federal Transit Administration, Washington, DC (United States)

    2012-11-01

    This report is the sixth in an annual series of reports that summarize the progress of fuel cell electric bus (FCEB) development in the United States and discuss the achievements and challenges of introducing fuel cell propulsion in transit. The report also provides a snapshot of current FCEB performance results over the last year.

  13. Enhancement of adhesion by a transition layer: Deposition of a-C film on ultrahigh molecular weight polyethylene (UHMWPE) by magnetron sputtering

    He, F. F.; Bai, W. Q.; Li, L. L.; Wang, X. L.; Xie, Y. J.; Jin, G.; Tu, J. P.

    2016-02-01

    An amorphous carbon (a-C) film is deposited on the plasma-treated UHMWPE substrate using a closed field unbalanced magnetron sputtering to improve its tribological properties. During the plasma treatment period, a transition layer is prepared by high energy ion bombardment at a bias voltage of -500 V to enhance the adhesion between the a-C film and the substrate. The mechanical and tribological properties of the a-C film were evaluated by nano-indentation and ball-on-disk tribometer. After deposition of a-C film with a thickness 900 nm, the nano-hardness of UHMWPE significantly increases from 47 MPa to 720 MPa and the wear rate decreases from 9.82 × 10-15 m3 N-1 m-1 to 4.78 × 10-15 m3 N-1 m-1 in bovine calf serum solution. The formation of the transition layer is believed to be the reason why the vertical adhesion between the a-C film and the UHMWPE substrate is enhanced.

  14. Electrochemical characterization and modeling of fuel cells via AC impedance and residence time distribution

    Payne, Robert R. U.

    The performance of commercially available fuel cells was tested under a variety of test conditions and models were formulated to explain the experimental results. Several techniques were applied to single cells and groups of cells, each probing a different phenomenon responsible for limiting the power output of the cells. Nonuiformity of fuel cells in a stack can drastically affect the total power output, because a stack of cells in series can only provide as much electrical current as the weakest cell. Uniformity of polymer electrolyte membrane (PEM) fuel cell voltage was measured for each cell of the 47 cells in a Nexa(TM) stack operating with 0 W and 800W supplied to an external load. Manufacturing consistency was assessed by comparing the mean cell potential of 10 different stacks. To minimize the cost of operating a stack, PEM fuel cells must be capable of withstanding higher impurity concentrations, which was accomplished by adding a manual purge line into the fuel exhaust line of a Nexa(TM) stack. The critical flow rate of the anode exhaust was determined by feeding gas diluted with up to 7% N2 to a stack supplying up to 200 W to an external load. The residence time distribution (RTD) of impurities in the stack was evaluated by injecting a pulse of inert gas and simultaneously measuring the time dependent voltage of each cell in the stack. A number of different compartmental flow models were developed to replicate the experimental data, but with minimal success; however, the added exhaust line successfully improved the impurity tolerance of the stack. Determining which and to what extent physical processes limit the electrical output of fuel cells is critical for evaluating system designs and performing diagnostics. Impedance spectroscopy was applied to cells to test the dynamic response of fuel cells and stacks thereof. Equivalent circuit models were fitted to the data, with each circuit element representing a different physical phenomenon. Data were

  15. Superconducting transition in ruthenocuprate RuSr2GdCu2O8 viewed from the studies of the imaginary part of ac susceptibility

    Zivkovic, I.; Drobac, D.; Ariosa, D.; Berger, H.; Pavuna, D.; Prester, M.

    2002-12-01

    We have measured two structurally similar superconducting systems, RuSr2GdCu2O8 and GdBa2Cu3O7 by means of high-resolution ac susceptibility. The real and the imaginary part of ac susceptibility of both bulk-ceramic and powdered samples have been studied down to the very small magnetic-field levels. We show that there are significant differences in the evolution of superconductivity in the two studied superconducting systems. In particular, we show that the superconducting transition in the grains in RuSr2GdCu2O8 system is masked with intrinsic magnetism of complex origin.

  16. SunLine Transit Agency Advanced Technology Fuel Cell Bus Evaluation: Fourth Results Report

    Eudy, L.; Chandler, K.

    2013-01-01

    SunLine Transit Agency, which provides public transit services to the Coachella Valley area of California, has demonstrated hydrogen and fuel cell bus technologies for more than 10 years. In May 2010, SunLine began demonstrating the advanced technology (AT) fuel cell bus with a hybrid electric propulsion system, fuel cell power system, and lithium-based hybrid batteries. This report describes operations at SunLine for the AT fuel cell bus and five compressed natural gas buses. The U.S. Department of Energy's National Renewable Energy Laboratory (NREL) is working with SunLine to evaluate the bus in real-world service to document the results and help determine the progress toward technology readiness. NREL has previously published three reports documenting the operation of the fuel cell bus in service. This report provides a summary of the results with a focus on the bus operation from February 2012 through November 2012.

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

    Carlsen, Robert W.

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

  18. SunLine Transit Agency Advanced Technology Fuel Cell Bus Evaluation: First Results Report

    Eudy, L.; Chandler, K.

    2011-03-01

    This report describes operations at SunLine Transit Agency for their newest prototype fuel cell bus and five compressed natural gas (CNG) buses. In May 2010, SunLine began operating its sixth-generation hydrogen fueled bus, an Advanced Technology (AT) fuel cell bus that incorporates the latest design improvements to reduce weight and increase reliability and performance. The agency is collaborating with the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) to evaluate the bus in revenue service. This report provides the early data results and implementation experience of the AT fuel cell bus since it was placed in service.

  19. Development of a New Class of Low Cost, High Frequency Link Direct DC to AC Converters for Solid Oxide Fuel Cells (SOFC)

    Prasad Enjeti; J.W. Howze

    2003-12-01

    This project proposes to design and develop a new class of power converters (direct DC to AC) to drastically improve performance and optimize the cost, size, weight and volume of the DC to AC converter in SOFC systems. The proposed topologies employ a high frequency link; direct DC to AC conversion approach. The direct DC to AC conversion approach is more efficient and operates without an intermediate dc-link stage. The absence of the dc-link, results in the elimination of bulky, aluminum electrolytic capacitors, which in turn leads to a reduction in the cost, volume, size and weight of the power electronic converter. The feasibility of two direct DC to AC converter topologies and their suitability to meet SECA objectives will be investigated. Laboratory proto-type converters (3-5kW) will be designed and tested in Phase-1. A detailed design trade-off study along with the test results will be available in the form of a report for the evaluation of SECA Industrial partners. This project proposes to develop a new and innovative power converter technology suitable for Solid Oxide Fuel Cell (SOFC) power systems in accordance with SECA objectives. The proposed fuel cell inverter (FCI) employs state of the art power electronic devices configured in two unique topologies to achieve direct conversion of DC power (24-48V) available from a SOFC to AC power (120/240V, 60Hz) suitable for utility interface and powering stand alone loads. The primary objective is to realize cost effective fuel cell converter, which operates under a wide input voltage range, and output load swings with high efficiency and improved reliability.

  20. Fuel Cell Transit Bus Evaluations: Joint Evaluation Plan for the U.S. Department of Energy and the Federal Transit Administration (Report and Appendix)

    Eudy, L.; Chandler, K.

    2010-11-01

    This document describes the fuel cell transit bus evaluations performed by the National Renewable Energy Laboratory (NREL) and funded by the U.S. Department of Energy (DOE) and the U.S. Department of Transportation's Federal Transit Administration (FTA). This document provides a description of the demonstration sites, funding sources, and data collection activities for fuel cell transit bus evaluations currently planned from FY10 through FY12.

  1. Fuel Cell Buses in U.S. Transit Fleets: Current Status 2012

    Eudy, L.; Chander, K.; Gikakis, C.

    2012-11-01

    This report is the sixth in an annual series of reports that summarize the progress of fuel cell electric bus (FCEB) development in the United States and discuss the achievements and challenges of introducing fuel cell propulsion in transit. The report also provides a snapshot of current FCEB performance results over the last year. There are 25 active FCEBs in demonstrations this year at eight locations.

  2. Transition challenges for alternative fuel vehicle and transportation systems

    Jeroen Struben; John D. Sterman

    2008-01-01

    Automakers are now developing alternatives to internal combustion engines (ICE), including hydrogen fuel cells and ICE – electric hybrids. Adoption dynamics for alternative vehicles are complex, owing to the size and importance of the auto industry and vehicle installed base. Diffusion of alternative vehicles is both enabled and constrained by powerful positive feedbacks arising from scale and scope economies, research and development, learning by doing, driver experience, word of mouth, and ...

  3. Optimization analysis of the nuclear fuel cycle transition to the last core

    Rebollo, L.; Blanco, J. [Union Fenosa Generacion, Madrid (Spain)

    2001-07-01

    The Zorita NPP was the first Spanish commercial nuclear reactor connected to the grid. It is a 160 MW one loop PWR, Westinghouse design, owned by UFG, in operation since 1968. The configuration of the reactor core is based on 69 fuel elements type 14 x 14, the standard reload of the present equilibrium cycle being based on 16 fuel elements with 3.6% enrichment in {sup 235}U. In order to properly plan the nuclear fuel management of the transition cycles to its end of life, presently foreseen by 2008, an based on the non-reprocessing option required by the policy of the Spanish Administration, a technical-economical optimization analysis has been performed. As a result, a fuel management strategy has been defined looking for getting simultaneously the minimum integral fuel cost of the transition from the present equilibrium cycle to the last core, as well as the minimum residual worth of the fuel remaining in the core after the final outage. Based on the ''lessons learned'' derived from the study, the time margin for the decision making has been determined, and a planning of the nuclear fuel supply for the transition reloads, specifying both the number of fuel elements and their enrichment in {sup 235}U, as been prepared. Finally, based on the calculated economical worth of the partially burned fuel of the last core, after the end of its operation cycle, a financial cover for yearly compensation from now on of the foreseen final lost has been elaborated. Most of the conceptual conclusions obtained are applicable to the other commercial nuclear reactors in operation owned by UFG, so that they are understood to be of general interest and broad application to commercial PWR. (author)

  4. Optimization analysis of the nuclear fuel cycle transition to the last core

    The Zorita NPP was the first Spanish commercial nuclear reactor connected to the grid. It is a 160 MW one loop PWR, Westinghouse design, owned by UFG, in operation since 1968. The configuration of the reactor core is based on 69 fuel elements type 14 x 14, the standard reload of the present equilibrium cycle being based on 16 fuel elements with 3.6% enrichment in 235U. In order to properly plan the nuclear fuel management of the transition cycles to its end of life, presently foreseen by 2008, an based on the non-reprocessing option required by the policy of the Spanish Administration, a technical-economical optimization analysis has been performed. As a result, a fuel management strategy has been defined looking for getting simultaneously the minimum integral fuel cost of the transition from the present equilibrium cycle to the last core, as well as the minimum residual worth of the fuel remaining in the core after the final outage. Based on the ''lessons learned'' derived from the study, the time margin for the decision making has been determined, and a planning of the nuclear fuel supply for the transition reloads, specifying both the number of fuel elements and their enrichment in 235U, as been prepared. Finally, based on the calculated economical worth of the partially burned fuel of the last core, after the end of its operation cycle, a financial cover for yearly compensation from now on of the foreseen final lost has been elaborated. Most of the conceptual conclusions obtained are applicable to the other commercial nuclear reactors in operation owned by UFG, so that they are understood to be of general interest and broad application to commercial PWR. (author)

  5. Diffusion and Gas Conversion Analysis of Solid Oxide Fuel Cells at Loads via AC Impedance

    Robert U. Payne

    2011-01-01

    Full Text Available Impedance measurements were conducted under practical load conditions in solid oxide fuel cells of differing sizes. For a 2 cm2 button cell, impedance spectra data were separately measured for the anode, cathode, and total cell. Improved equivalent circuit models are proposed and applied to simulate each of measured impedance data. Circuit elements related to the chemical and physical processes have been added to the total-cell model to account for an extra relaxation process in the spectra not measured at either electrode. The processes to which elements are attributed have been deduced by varying cell temperature, load current, and hydrogen concentration. Spectra data were also obtained for a planar stack of five 61 cm2 cells and the individual cells therein, which were fitted to a simplified equivalent circuit model of the total button cell. Similar to the button cell, the planar cells and stack exhibit a pronounced low-frequency relaxation process, which has been attributed to concentration losses, that is, the combined effects of diffusion and gas conversion. The simplified total-cell model approximates well the dynamic behavior of the SOFC cells and the whole stack.

  6. Proliferation resistant fuel cycle system for the transition from light water reactors to fast reactors

    Full text: Introduction of commercial fast reactors (FR) is predicted to start around 2050 in Japan. Effective utilization of plutonium in FR is important for the sustainable electricity generation by nuclear. Successive replacement of light water reactors (LWR) to FR will take more than 60-years and reasonable fuel cycle management is necessary during this period. The transition scenario has various unpredictable factors such as introduction speed and time of FR, and flexible fuel cycle system was proposed to respond to these factors. The system consists of LWR and FR spent fuels reprocessing for reduction of LWR spent fuel volume and FR fuel fabrication. LWR fuel reprocessing only carries out about 90% uranium removal from LWR spent fuel, then the composition of residual spent fuel called recycle material is about 50% uranium, 15% plutonium and 35% fission products + minor actinides. Recycle material is transferred to FR fuel reprocessing to recover plutonium and uranium followed by mixed oxide (MOX) fuel fabrication for FR with radioactive impurities. Depending on the introduction time of FR, recycle material (about 1/10 volume of original spent fuel) may be stored for future use. The system has some characteristics compared with ordinary system that consists of full reprocessing facilities for LWR and FR spent fuels to produce FR fresh fuels. The LWR reprocessing facility becomes much smaller due to no Pu-U recovery and fabrication. The recycle materials can supply higher content of plutonium to FR and be compactly stored in case of FR introduction delay. Plutonium always contains uranium and impurities (fission products and minor actinides), thus the system maintains high proliferation resistance. The plutonium balance was calculated under several conditions, which revealed that the system could supply enough and no excess plutonium to FR

  7. Thermal-hydraulic effects of transition to improved System 80TM fuel

    ABB CE's improved System 80TM PWR fuel design includes GUARDIAN debris-resistant features and laser-welded Zircaloy grids. The GUARDIAN features include an Inconel grid with debris-filtering features located just above the Lower End Fitting, and a solid fuel rod bottom end cap that extends above the filtering features. Tests and analyses were done to establish the impact of these design improvements on fuel assembly hydraulic performance. Further analysis was done to determine the mixed core thermal-hydraulic performance as the transition is made over two fuel cycles to a full core of the improved System 80TM fuel. Results confirm that the Thermal-Hydraulic (T-H) effects of the reduction in hydraulic resistance between the improved and resident fuel due to the laser-welded Zircaloy grids offsets the effects of the increased resistance GUARDIAN grid. Therefore, the mechanically improved System 80TM fuel can be implemented with no net impact on Departure from Nucleate Boiling (DNB) margin in transition cores. (author)

  8. Considerations for the transition from fuel cell R ampersand D to manufacturing

    There are a growing number of contractors within the present fuel cell community who have the potential of becoming high volume manufacturers of fuel cell power plants or components. Many are transitioning from basic research operations to manufacturing for the first time. Moving a product from the R ampersand D stage to a viable commercial product depends upon many factors. Some companies are more successful at it than others. We believe there is an underlying transition process from invention to market that is much the same for large, well established firms, as it is for start-ups. How well the process is understood and executed often determines the winners and losers in product commercialization. This paper presents a viewpoint on considerations for transitioning a new technology into commercial production and discusses some affects on organizational development

  9. Flame spread over electrical wire with AC electric fields: Internal circulation, fuel vapor-jet, spread rate acceleration, and molten insulator dripping

    Lim, Seungjae

    2015-04-01

    The effect of electric field on the characteristics of flame spread along a polyethylene (PE) insulated electrical wire was investigated experimentally by varying the AC frequency and voltage applied to the wire. The results showed that the flame spread rate was accelerated due to the convergence of electric flux near the end of wire, having three distinct regimes depending on applied voltage. In each regime, several subregimes could be identified depending on AC frequency. Flame shape (height and width) and slanted direction of the spreading flame were influenced differently. Fuel-vapor jets were ejected from the molten PE surface even for the baseline case without the application of an electric field; this could be attributed to the bursting of fuel vapor bubbles generated from internal boiling at the molten PE surface. An internal circulation of molten-PE was also observed as a result of non-uniform heating by the spreading flame. In the high voltage regime with a high AC frequency, excessive dripping of molten PE led to flame extinction.

  10. Timing is everything : along the fossil fuel transition pathway.

    Kobos, Peter Holmes; Walker, La Tonya Nicole; Malczynski, Leonard A.

    2013-10-01

    People save for retirement throughout their career because it is virtually impossible to save all you'll need in retirement the year before you retire. Similarly, without installing incremental amounts of clean fossil, renewable or transformative energy technologies throughout the coming decades, a radical and immediate change will be near impossible the year before a policy goal is set to be in place. Therefore, our research question is,To meet our desired technical and policy goals, what are the factors that affect the rate we must install technology to achieve these goals in the coming decades?' Existing models do not include full regulatory constraints due to their often complex, and inflexible approaches to solve foroptimal' engineering instead ofrobust' and multidisciplinary solutions. This project outlines the theory and then develops an applied software tool to model the laboratory-to-market transition using the traditional technology readiness level (TRL) framework, but develops subsequent and a novel regulatory readiness level (RRL) and market readiness level (MRL). This tool uses the ideally-suited system dynamics framework to incorporate feedbacks and time delays. Future energy-economic-environment models, regardless of their programming platform, may adapt this software model component framework ormodule' to further vet the likelihood of new or innovative technology moving through the laboratory, regulatory and market space. The prototype analytical framework and tool, called the Technology, Regulatory and Market Readiness Level simulation model (TRMsim) illustrates the interaction between technology research, application, policy and market dynamics as they relate to a new or innovative technology moving from the theoretical stage to full market deployment. The initial results that illustrate the model's capabilities indicate for a hypothetical technology, that increasing the key driver

  11. Zero Emission Bay Area (ZEBA) Fuel Cell Bus Demonstration Results. Fourth Report

    Eudy, Leslie [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Post, Matthew [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2015-07-02

    This report presents results of a demonstration of fuel cell electric buses (FCEB) operating in Oakland, California. Alameda-Contra Costa Transit District (AC Transit) leads the Zero Emission Bay Area (ZEBA) demonstration, which includes 12 advanced-design fuel cell buses and two hydrogen fueling stations. The FCEBs in service at AC Transit are 40-foot, low-floor buses built by Van Hool with a hybrid electric propulsion system that includes a US Hybrid fuel cell power system and EnerDel lithium-based energy storage system. The buses began revenue service in May 2010.

  12. One-region model predicting water temperature and level in a spent fuel pit during loss of all AC power supplies

    A prediction system with a one-region model was developed to predict water temperature in a spent fuel pit (SFP) after the shutdown of its cooling systems based on three-dimensional (3D) thermal hydraulic behavior calculated by using the CFD software, FLUENT 6.3.26. The system was extended to calculate the water level in the SFP during loss of all AC power supplies. In the prediction system, decay heat calculated by using the burn-up calculation software, ORIGEN 2.2, and the previously proposed correlation for evaporation heat fluxes from the water surface to air were used. Predicted results were compared with 3D calculations and measured temperatures for the shutdown of cooling systems and with the water temperature and level measured in SFPs at the Fukushima Daiichi Nuclear Power Station for loss of all AC power supplies. As a result, the predicted temperatures were found to agree well with the 3D calculations and it was confirmed that ORIGEN 2.2 well predicted decay heat for fuel assemblies with large decay heat which had been taken relatively recently from the shutdown reactor core. However, it was shown that decay heat predicted by ORIGEN 2.2 was overestimated for longtime cooled fuel assemblies with small decay heat and the previously proposed evaporation heat flux correlation overestimated the water temperature in the SFP, too. (author)

  13. Advances in simulating non-congruent phase transitions of hyperstoichiometric uranium dioxide fuel

    A model is being developed to simulate UO2 at very high temperatures incorporating the effects of non-congruent phase transitions. In particular, the melting transformation and the possible 'Λ-transition' is being investigated to help support the design and analysis of experimental work being conducted as part of nuclear safety research. This work includes the interpretation of the behaviour of operating CANDU fuel under upset conditions, where centerline melting may potentially occur (particularly if the fuel is oxidized). The model presented here numerically solves a system of coupled nonlinear differential equations as derived from fundamental principles. The results of the model present here compare well against laser flash experiments in recently published literature. (author)

  14. Simulations of the Fuel Economy and Emissions of Hybrid Transit Buses over Planned Local Routes

    Gao, Zhiming [ORNL; LaClair, Tim J [ORNL; Daw, C Stuart [ORNL; Smith, David E [ORNL; Franzese, Oscar [ORNL

    2014-01-01

    We present simulated fuel economy and emissions city transit buses powered by conventional diesel engines and diesel-hybrid electric powertrains of varying size. Six representative city drive cycles were included in the study. In addition, we included previously published aftertreatment device models for control of CO, HC, NOx, and particulate matter (PM) emissions. Our results reveal that bus hybridization can significantly enhance fuel economy by reducing engine idling time, reducing demands for accessory loads, exploiting regenerative braking, and shifting engine operation to speeds and loads with higher fuel efficiency. Increased hybridization also tends to monotonically reduce engine-out emissions, but trends in the tailpipe (post-aftertreatment) emissions involve more complex interactions that significantly depend on motor size and drive cycle details.

  15. Solar Electricity and Solar Fuels: Status and Perspectives in the Context of the Energy Transition.

    Armaroli, Nicola; Balzani, Vincenzo

    2016-01-01

    The energy transition from fossil fuels to renewables is already ongoing, but it will be a long and difficult process because the energy system is a gigantic and complex machine. Key renewable energy production data show the remarkable growth of solar electricity technologies and indicate that crystalline silicon photovoltaics (PV) and wind turbines are the workhorses of the first wave of renewable energy deployment on the TW scale around the globe. The other PV alternatives (e.g., copper/indium/gallium/selenide (CIGS) or CdTe), along with other less mature options, are critically analyzed. As far as fuels are concerned, the situation is significantly more complex because making chemicals with sunshine is far more complicated than generating electric current. The prime solar artificial fuel is molecular hydrogen, which is characterized by an excellent combination of chemical and physical properties. The routes to make it from solar energy (photoelectrochemical cells (PEC), dye-sensitized photoelectrochemical cells (DSPEC), PV electrolyzers) and then synthetic liquid fuels are presented, with discussion on economic aspects. The interconversion between electricity and hydrogen, two energy carriers directly produced by sunlight, will be a key tool to distribute renewable energies with the highest flexibility. The discussion takes into account two concepts that are often overlooked: the energy return on investment (EROI) and the limited availability of natural resources-particularly minerals-which are needed to manufacture energy converters and storage devices on a multi-TW scale. PMID:26584653

  16. The energy transition in action: urban domestic fuel choices in a changing Zimbabwe

    Two questionnaire surveys of fuel use by low-income households in Zimbabwe were conducted in four small towns in 1994, and in these towns plus four larger towns in 1999. An energy transition from wood through kerosene to electricity occurred (a) with rising household income, (b) with increasing electrification status among towns and (c) over time in the smaller towns, in spite of falling household incomes in two of the towns. Increasing discrepancy in the incomes of higher and lower income groups over time was not associated with greater divergence in their fuel choices. By 1999 electricity was used by almost all households in towns with good electricity supplies, while use of firewood in these towns was infrequent. However, even the wealthiest households continued to combine electricity with other fuels, usually kerosene. Electricity use by less affluent households is apparently limited by lack of connections in the home and by access to appliances, while fuel prices, which are subject to government subsidies and fell in real terms over 5 years, have been less important. Zimbabwe's urban domestic energy policy has had considerable success in terms of equity, but this is increasingly difficult to maintain given present economic and political uncertainty

  17. Droplet entrainment and deposition rate models for determination of boiling transition in BWR fuel assembly

    Droplet entrainment and deposition rates are of vital importance for mechanistic determination of critical power and location of boiling transition in a BWR fuel assembly. Data from high-pressure, high-temperature steam-water adiabatic experiments conducted in very tall test sections are used to develop a combination of equilibrium entrainment-deposition rate. Application of this combination to the heated tests conducted in a shorter test section of typical height of a BWR fuel assembly shows that correct split of total liquid in form of the film and droplets at the onset of annular-mist flow regime is also important to obtain good prediction of film flow rates/entrainment fraction. The improved model is then applied to simulate critical power tests in annulus and rod bundles. (author)

  18. Fast reactor core design studies to cope with TRU fuel composition changes in the LWR-to-FBR transition period

    As part of the Fast Reactor Cycle Technology Development Project (FaCT Project), sodium-cooled fast reactor core design efforts have been made to cope with the TRU fuel composition changes expected during LWR-to-FBR transition period, in which a various kind of TRU fuel compositions are available depending on the characteristics of the LWR spent fuels and a way of recycling them. A 750 MWe mixed-oxide fuel core is firstly defined as a FaCT medium-size reference core and its neutronics characteristics are determined. The core is a high internal conversion type and has an average burnup of 150 GWD/T. The reference TRU fuel composition is assumed to come from the FBR equilibrium state. Compared to the LWR-to-FBR transition period, the TRU fuels in the FBR equilibrium period are multi-recycled through fast reactors and have a different composition. An available TRU fuel composition is determined by fast reactor spent fuel multi-recycling scenarios. Then the FaCT core corresponding to the TRU fuel with different compositions is set according to the TRU fuel composition changes in LWR-to-FBR transition period, and the key core neutronics characteristics are assessed. It is shown that among the core neutronics characteristics, the burnup reactivity and the safety parameters such as sodium void reactivity and Doppler coefficient are significantly influenced by the TRU fuel composition changes. As a result, a general characteristic in the FaCT core design to cope with TRU fuel composition changes is grasped and the design envelopes are identified in terms of the burnup reactivity and the safety parameters. (author)

  19. Dual role of an ac driving force and the underlying two distinct order–disorder transitions in the vortex phase diagram of Ca{sub 3}Ir{sub 4}Sn{sub 13}

    Kumar, Santosh, E-mail: santoshkumar@phy.iitb.ac.in [Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076 (India); Singh, Ravi P.; Thamizhavel, A. [Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400005 (India); Tomy, C.V., E-mail: tomy@phy.iitb.ac.in [Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076 (India); Grover, A.K. [Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400005 (India); Department of Physics, Panjab University, Chandigarh 160014 (India)

    2014-11-15

    Highlights: • This work pertains to new findings related to a broad SMP anomaly. • Broad SMP prima facie encompasses two phase transformations in vortex matter. • We demarcated two phase boundaries pertaining to order–disorder transitions which have quasi first-order nature. - Abstract: We present distinct demarcation of the Bragg glass (BG) to multi-domain vortex glass (VG) transition line and the eventual amorphization of the VG phase in a weakly pinned single crystal of the superconducting compound Ca{sub 3}Ir{sub 4}Sn{sub 13} on the basis of comprehension of the different yields about the second magnetization peak (SMP) anomaly in the dc magnetization and the corresponding anomalous feature in the ac susceptibility measurements. The shaking by a small ac magnetic field, inevitably present in the ac susceptibility measurements, is seen to result in contrasting responses in two different portions of the field-temperature (H, T) phase space of the multi-domain VG. In one of the portions, embracing the BG to VG transition across the onset of the SMP anomaly, the ac drive is surprisingly seen to assist the transformation of the well ordered BG phase to a lesser ordered VG phase. The BG phase exists as a superheated state over a small portion of the VG space and this attests to the first order nature of the BG to VG transition.

  20. Transition from ignition to flame spread over thick fuels in a simulated microgravity environment

    Wang, Shuangfeng; Lu, Zhanbin

    Ignition of solid fuels and subsequent transition to flame spread is of fundamental interest and practical importance for spacecraft fire safety. Most previous reseach on microgravity flame spread has involved purely opposed or purely concurrent flow, i.e. ignition occurs at one end of the fuel sample. In this study, a narrow channel apparatus is employed to investigate the phenomenon of flame spread over a thermally thick PMMA sheet in narrow gaps that essentially suppress buoyancy and produce a low-gravity flame spread environment. The ignition is initiated in the middle of the sample, and the focus is to determine the effects of atmosphere oxygen concentration and flow velocity on flame spread behavior in microgravity. Experimental results show that a single flame propagates upstream when oxygen concentration and flow velocity are relatively low. As oxygen and flow velocity are increased to levels high enough, however, the flame may propagate upstream and also downstream. Based on oxygen side diffusion, oxygen shadowing, and fuel depletion effect, the various observed flame behaviors are explained.

  1. Cost Probability Analysis of China's Nuclear Fuel Cycle Transition

    The Chinese government has already determined to develop the closed nuclear fuel cycle, its long-term roadmap of spent fuel management has not been decided yet. Currently, it seems that China's booming economy gives abundant financial assurance to develop nuclear programs in full play according to its near-term national plans. However, the viability and sustainability of nuclear power always depends critically on its economics. Therefore, it is necessary to conduct a well focused cost-benefit and objective analysis of China's ongoing nuclear power programs with the future prospects. In this study, we conduct a comparative analysis of electricity generation cost in four reference nuclear fuel cycle transition scenarios by 2050. Direct disposal is assumed to produce the cheapest LCT as low as 62.688 mills/kWh compared to the other options. However, after performing a relative uncertainty study, the results show that the capital cost of reactor is the key cost component which leads to the cost gap

  2. High temperature phase transitions in nuclear fuels of the fourth generation

    Understanding the behaviour of nuclear materials in extreme conditions is of prime importance for the analysis of the operation limits of nuclear fuels, and prediction of possible nuclear reactor accidents, relevant to the general objectives of nuclear safety research. The main purpose of this thesis is the study of high temperature phase transitions in nuclear materials, with special attention to the candidate fuel materials for the reactors of the 4. Generation. In this framework, material properties need to be investigated at temperatures higher than 2500 K, where equilibrium conditions are difficult to obtain. Laser heating combined with fast pyrometer is the method used at the European Institute for Transuranium Elements (JRC - ITU). It is associated to a novel process used to determine phase transitions, based on the detection, via a suited low-power (mW) probe laser, of changes in surface reflectivity that may accompany solid/liquid phase transitions. Fast thermal cycles, from a few ms up to the second, under almost container-free conditions and control atmosphere narrow the problem of vaporisation and sample interactions usually meet with traditional method. This new experimental approach has led to very interesting results. It confirmed earlier research for material systems known to be stable at high temperature (such as U-C) and allowed a refinement of the corresponding phase diagrams. But it was also feasible to apply this method to materials highly reactive, thus original results are presented on PuO2, NpO2, UO2-PuO2 and Pu-C systems. (author)

  3. Technical Approach and Plan for Transitioning Spent Nuclear Fuel (SNF) Project Facilities to the Environmental Restoration Program

    SKELLY, W.A.

    1999-10-06

    This document describes the approach and process in which the 100-K Area Facilities are to be deactivated and transitioned over to the Environmental Restoration Program after spent nuclear fuel has been removed from the K Basins. It describes the Transition Project's scope and objectives, work breakdown structure, activity planning, estimated cost, and schedule. This report will be utilized as a planning document for project management and control and to communicate details of project content and integration.

  4. Technical Approach and Plan for Transitioning Spent Nuclear Fuel (SNF) Project Facilities to the Environmental Restoration Program

    This document describes the approach and process in which the 100-K Area Facilities are to be deactivated and transitioned over to the Environmental Restoration Program after spent nuclear fuel has been removed from the K Basins. It describes the Transition Project's scope and objectives, work breakdown structure, activity planning, estimated cost, and schedule. This report will be utilized as a planning document for project management and control and to communicate details of project content and integration

  5. Performance of Frequency Division Multiplexing Readout System for AC-Biased Transition-Edge Sensor X-ray Microcalorimeters

    Yamamoto, R.; Sakai, K.; Takei, Y.; Yamasaki, N. Y.; Mitsuda, K.

    2014-08-01

    Frequency division multiplexing (FDM) is a promising approach to read out a large format transition-edge sensor (TES) array for future astrophysical missions. We constructed a four channel FDM readout system using baseband feedback in the MHz band. We demonstrated the principle of our FDM method with an actual TES array, a multiplexing SQUID and LC band-pass filters under 100 mK. The resonant frequencies of LC filters were consistent with the design value with an accuracy of better than 3 %. We successfully obtained X-ray pulses from two TESs simultaneously but the energy resolution was degraded to about 100 eV at 5.9 keV and crosstalk effects were observed. The origin of the crosstalk effects is investigated by modified setups. Based on comparative experiments and numerical calculations, we conclude that the non-linearity of the SQUID is the cause of some of the crosstalk effects. Unlike the regular crosstalk effect from the adjoining channels, the crosstalk effect due to non-linearity observed in this paper occurs in all channels. Solving these problems will help us to obtain FDM readout with sufficient energy resolution.

  6. Transition costs to the closed nuclear fuel cycle with fast reactors and their impact on the strategies of its introduction

    The paper presents results of the study on economic aspects of the transition from the current nuclear energy system (NS) overwhelmingly based on the open nuclear fuel cycle (NFC) with thermal reactors to the NS with substantial inclusion of the closed NFC and balanced fleet of thermal and fast reactors. This transition will require pre-commercial investments (transition costs) which include R and D cost, investments in prototype/demonstration facilities, non-recurring NPP deployment costs, etc. Assessments made in the countries that were leading in the development of fast reactors and associated fuel cycle have shown that the scale of transition costs is rather high. The approach used in the study includes analysis of scenarios for technological structure of nuclear power development in the 21. century by taking into account (i) two groups of counties; group one develops closed NFC with fast reactors (CNFCFR) while other does not; (ii) need for nuclear energy for the two group over the next 100 years; (iii) uranium resource availability and costs; (iv) the construction and operation costs of nuclear reactors and fuel cycle facilities; (v) R and D investments and timings for development of CNFC-FR technologies; etc. The study demonstrates that the transition costs have significant impact on economic viability of the CNFC-FR systems. In some cases, the timings and amount of investments necessary for transition to CNFC-FR do not fit to the expected returns from new nuclear capacity deployments and thus exclude the CNFC-FR from optimal capacity expansion strategies. In general, transition costs formulate additional rules with regard to building of the optimal architecture of the global nuclear fuel cycle and their accounting leads to many important conclusions as discussed in the paper. (authors)

  7. Assessment of alternative fuel and powertrain transit bus options using real-world operations data: Life-cycle fuel and emissions modeling

    Highlights: • We present a practical fuel and emissions modeling tool for alternative fuel buses. • The model assesses well-to-wheels emissions impacts of bus fleet decisions. • Mode-based approach is used to account for duty cycles and local conditions. • A case study using real-world operations data from Atlanta, GA is presented. • Impacts of alternative bus options depend on operating and geographic features. - Abstract: Hybrid and electric powertrains and alternative fuels (e.g., compressed natural gas (CNG), biodiesel, or hydrogen) can often reduce energy consumption and emissions from transit bus operations relative to conventional diesel. However, the magnitude of these energy and emissions savings can vary significantly, due to local conditions and transit operating characteristics. This paper introduces the transit Fuel and Emissions Calculator (FEC), a mode-based life-cycle emissions modeling tool for transit bus and rail technologies that compares the performance of multiple alternative fuels and powertrains across a range of operational characteristics and conditions. The purpose of the FEC is to provide a practical, yet technically sophisticated tool for regulatory agencies and policy analysts in assessing transit fleet options. The FEC’s modal modeling approach estimates emissions as a function of engine load, which in turn is a function of transit service parameters, including duty cycle (idling and speed-acceleration profile), road grade, and passenger loading. This approach allows for customized assessments that account for local conditions. Direct emissions estimates are derived from the scaled tractive power (STP) operating mode bins and emissions factors employed in the U.S. EPA’s MOVES (MOtor Vehicle Emissions Simulator) model. Life-cycle emissions estimates are calculated using emissions factors from the GREET (Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation) model. The case study presented in this paper

  8. Storage Free Smart Energy Management for Frequency Control in a Diesel-PV-Fuel Cell-Based Hybrid AC Microgrid.

    Sekhar, P C; Mishra, S

    2016-08-01

    This paper proposes a novel, smart energy management scheme for a microgrid, consisting of a diesel generator and power electronic converter interfaced renewable energy-based generators, such as photovoltaic (PV) and fuel cell, for frequency regulation without any storage. In the proposed strategy, output of the PV is controlled in coordination with other generators using neurofuzzy controller, either only for transient frequency regulation or for both transient and steady-state frequency regulation, depending on the load demand, thereby eliminating the huge storage requirements. The option of demand response control is also explored along with the generation control. For accurate and quick tracking of maximum power point and its associated reserve power from the PV generator, this paper also proposes a novel adaptive-predictor-corrector-based tracking mechanism. PMID:26011895

  9. Public perception related to a hydrogen hybrid internal combustion engine transit bus demonstration and hydrogen fuel

    Hydrogen has been widely considered as a potentially viable alternative to fossil fuels for use in transportation. In addition to price competitiveness with fossil fuels, a key to its adoption will be public perceptions of hydrogen technologies and hydrogen fuel. This paper examines public perceptions of riders of a hydrogen hybrid internal combustion engine bus and hydrogen as a fuel source

  10. Fuel cycle: the transition between the third and the fourth generation of reactors

    Many challenges arrive today for the french research and development on the fuel cycle: promote the industrial technologies, improve the world increase of the nuclear and adapt the fuel cycle technologies to the future reactors. In this framework the report presents after a recall on the fuel cycle, the researches on the fuel, the optimization of the recycling, the wastes management, the simulation and Phenix an experimentation tool for the fuel. (A.L.B.)

  11. Critical factors in transitioning from fuel cell to cold fusion technology

    The fuel cell industry possesses much of the required manufacturing equipment and knowledge-base (e.g., proton conduction and hydrogen safety) necessary to develop cold fusion systems. Key factors in making a transition to cold fusion technology are discussed. Loading of reaction material can be provided by electrolytic charging and high gas over-pressure. Effective pressures over 10,000 atmospheres are required in cold fusion systems, giving a loading of H/M = 1; and a combination of loading methods is highly desirable. Systems must be designed to provide continuous flow of hydrogen ions (muchgt1017/sec for ten kilowatts), with an input power source of 50 watts (est.). Cold fusion experiments have shown that helium is formed during the reaction, and physical changes occur in the reaction material. These revelations impact design and operation of cold fusion systems, as the reaction material must be replaced periodically, while the systems must maintain integrity during operation. Safety and cost are also highly important considerations

  12. Fuel poverty is facing a data challenge - Which strategies to struggle against fuel poverty? Propositions for an ecologic and social transition policy

    The authors address three main questions: how are structured the network of actors and the tools for the struggle against fuel poverty, what are the specific data challenges faced by the actors and the possible responses, and which lessons can be learned for the governance of energy transition in its whole. After a presentation of the context of fuel poverty (analysis of tools for the struggle against fuel poverty, the use of social-energetic data), this study, based on about forty interviews of various actors and on a workshop, proposes an analysis framework which distinguishes six steps in the definition and implementation of policies of struggle against fuel poverty. After a description of the current status and an identification of required improvements for each step, the authors propose a set of recommendations, draw lessons for urban policies aimed at an ecologic transformation and a modernisation of the social protection system in terms of level of intervention, scope of actions, and ownership and access to data bases. These recommendations more particularly address the definition of fuel poverty, its diagnosis at the national and at the territorial level, a better identification of concerned households, and an assessment of existing arrangements

  13. Optimization of fuel cell membrane electrode assemblies for transition metal ion-chelating ordered mesoporous carbon cathode catalysts

    Johanna K. Dombrovskis; Cathrin Prestel; Anders E. C. Palmqvist

    2014-01-01

    Transition metal ion-chelating ordered mesoporous carbon (TM-OMC) materials were recently shown to be efficient polymer electrolyte membrane fuel cell (PEMFC) catalysts. The structure and properties of these catalysts are largely different from conventional catalyst materials, thus rendering membrane electrode assembly (MEA) preparation parameters developed for conventional catalysts not useful for applications of TM-OMC catalysts. This necessitates development of a methodology to incorporate...

  14. Heating of the fuel mixture due to viscous stress ahead of accelerating flames in deflagration-to-detonation transition

    Valiev, Damir; Bychkov, Vitaly; Akkerman, V'yacheslav; Eriksson, Lars-Erik; Marklund, Mattias

    2008-01-01

    The role of viscous stress in heating of the fuel mixture in deflagration-to-detonation transition in tubes is studied both analytically and numerically. The analytical theory is developed in the limit of low Mach number; it determines temperature distribution ahead of an accelerating flame with maximum achieved at the walls. The heating effects of viscous stress and the compression wave become comparable at sufficiently high values of the Mach number. In the case of relatively large Mach num...

  15. Green trucks: transitioning the freight truck industry to low and zero emission fuel systems

    Kalthoff, Jarrett Reid

    2012-01-01

    The freight truck industry in Canada is the lifeblood of many communities throughout the country. These communities rely upon overland freight for everything from food to fuel. The continued operation of this industry is fundamentally dependent on the consumption of fossil fuels. This dependence leads to two challenges facing the freight industry: (1) fossil fuels are expensive, finite resources that are prone to dramatic surges in price; and, (2) the consumption and combustion of fossil fuel...

  16. Hopes, Hypes and Disappointments: On the role of expectations for sustainability transitions : A case study on hydrogen and fuel cell technology for transport

    Budde, B

    2015-01-01

    The aim of this thesis is to better understand the role of (changing) expectations for innovation and transition processes. It aims to gain insights in the processes leading to periods of hypes, followed by disappointment and the effects of such expectation dynamics on transitions. Empirically this thesis focusses on fuel cell technology. Already during the 1990s fuel cell technology became one of the most promising technologies to power the car of the future. Early optimistic expectations ho...

  17. Transitions in Zr, Hf, Ta, W, Re, Hg, Ac and U ions with high sensitivity to variation of the fine-structure constant

    Berengut, J. C.; Dzuba, V. A.; Flambaum, V. V.

    2011-01-01

    We study transitions between ground and low-energy excited states of heavy ions corresponding to s-d single-electron transitions or s^2-d^2 double-electron transitions. The large nuclear charge Z and significant change in angular momentum of electron orbitals make these transitions highly sensitive to a potential variation in the fine-structure constant, alpha. The transitions may be considered as candidates for laboratory searches for space-time variation of alpha.

  18. Nuclear Energy R and D Imperative 3: Enable a Transition Away from Fossil Fuel in the Transportation and Industrial Sectors

    As described in the Department of Energy Office of Nuclear Energy's Nuclear Energy R and D Roadmap, nuclear energy can play a significant role in supplying energy for a growing economy while reducing both our dependence on foreign energy supplies and emissions from the burning of fossil fuels. The industrial and transportation sectors are responsible for more than half of the greenhouse gas emissions in the U.S., and imported oil supplies 70% of the energy used in the transportation sector. It is therefore important to examine the various ways nuclear energy can facilitate a transition away from fossil fuels to secure environmentally sustainable production and use of energy in the transportation and manufacturing industry sectors. Imperative 3 of the Nuclear Energy R and D Roadmap, entitled 'Enable a Transition Away from Fossil Fuels by Producing Process Heat for use in the Transportation and Industrial Sectors', addresses this need. This document presents an Implementation Plan for R and D efforts related to this imperative. The expanded use of nuclear energy beyond the electrical grid will contribute significantly to overcoming the three inter-linked energy challenges facing U.S. industry: the rising and volatile prices for premium fossil fuels such as oil and natural gas, dependence on foreign sources for these fuels, and the risks of climate change resulting from carbon emissions. Nuclear energy could be used in the industrial and transportation sectors to: (1) Generate high temperature process heat and electricity to serve industrial needs including the production of chemical feedstocks for use in manufacturing premium fuels and fertilizer products, (2) Produce hydrogen for industrial processes and transportation fuels, and (3) Provide clean water for human consumption by desalination and promote wastewater treatment using low-grade nuclear heat as a useful additional benefit. Opening new avenues for nuclear energy will significantly enhance our nation

  19. Nuclear Energy R&D Imperative 3: Enable a Transition Away from Fossil Fuel in the Transportation and Industrial Sectors

    David Petti; J. Stephen Herring

    2010-03-01

    As described in the Department of Energy Office of Nuclear Energy’s Nuclear Energy R&D Roadmap, nuclear energy can play a significant role in supplying energy for a growing economy while reducing both our dependence on foreign energy supplies and emissions from the burning of fossil fuels. The industrial and transportation sectors are responsible for more than half of the greenhouse gas emissions in the U.S., and imported oil supplies 70% of the energy used in the transportation sector. It is therefore important to examine the various ways nuclear energy can facilitate a transition away from fossil fuels to secure environmentally sustainable production and use of energy in the transportation and manufacturing industry sectors. Imperative 3 of the Nuclear Energy R&D Roadmap, entitled “Enable a Transition Away from Fossil Fuels by Producing Process Heat for use in the Transportation and Industrial Sectors”, addresses this need. This document presents an Implementation Plan for R&D efforts related to this imperative. The expanded use of nuclear energy beyond the electrical grid will contribute significantly to overcoming the three inter-linked energy challenges facing U.S. industry: the rising and volatile prices for premium fossil fuels such as oil and natural gas, dependence on foreign sources for these fuels, and the risks of climate change resulting from carbon emissions. Nuclear energy could be used in the industrial and transportation sectors to: • Generate high temperature process heat and electricity to serve industrial needs including the production of chemical feedstocks for use in manufacturing premium fuels and fertilizer products, • Produce hydrogen for industrial processes and transportation fuels, and • Provide clean water for human consumption by desalination and promote wastewater treatment using low-grade nuclear heat as a useful additional benefit. Opening new avenues for nuclear energy will significantly enhance our nation’s energy

  20. Transition from HEU to LEU fuel in Romania`s 14-MW TRIGA reactor

    Bretscher, M.M.; Snelgrove, J.L.

    1991-12-31

    The 14-MW TRIGA steady state reactor (SSR) located in Pitesti, Romania, first went critical in the fall of 1979. Initially, the core configuration for full power operation used 29 fuel clusters each containing a 5 {times} 5 square array of HEU (10 wt%) -- ZrH -- Er (2.8 wt%) fuel-moderator rods (1.295 cm o.d.) clad in Incology. With a total inventory of 35 HEU fuel clusters, burnup considerations required a gradual expansion of the core from 29 to 32 and finally to 35 clusters before the reactor was shut down because of insufficient excess reactivity. At this time each of the original 29 fuel clusters had an overage {sup 235}U burnup in the range from 50 to 62%. Because of the US policy regarding the export of highly enriched uranium, fresh HEU TRIGA replacement fuel is not available. After a number of safety-related measurements, the SSR is expected to resume full power operation in the near future using a mixed core containing five LEU TRIGA clusters of the same geometry as the original fuel but with fuel-moderator rods containing 45 wt% U (19.7% {sup 235}U enrichment) and 1.1 wt% Er. Rods for 14 additional LEU fuel clusters will be fabricated by General Atomics. In support of the SSR mixed core operation numerous neutronic calculations have been performed. This paper presents some of the results of those calculations.

  1. Transition from HEU to LEU fuel in Romania's 14-MW TRIGA reactor

    Bretscher, M.M.; Snelgrove, J.L.

    1991-01-01

    The 14-MW TRIGA steady state reactor (SSR) located in Pitesti, Romania, first went critical in the fall of 1979. Initially, the core configuration for full power operation used 29 fuel clusters each containing a 5 {times} 5 square array of HEU (10 wt%) -- ZrH -- Er (2.8 wt%) fuel-moderator rods (1.295 cm o.d.) clad in Incology. With a total inventory of 35 HEU fuel clusters, burnup considerations required a gradual expansion of the core from 29 to 32 and finally to 35 clusters before the reactor was shut down because of insufficient excess reactivity. At this time each of the original 29 fuel clusters had an overage {sup 235}U burnup in the range from 50 to 62%. Because of the US policy regarding the export of highly enriched uranium, fresh HEU TRIGA replacement fuel is not available. After a number of safety-related measurements, the SSR is expected to resume full power operation in the near future using a mixed core containing five LEU TRIGA clusters of the same geometry as the original fuel but with fuel-moderator rods containing 45 wt% U (19.7% {sup 235}U enrichment) and 1.1 wt% Er. Rods for 14 additional LEU fuel clusters will be fabricated by General Atomics. In support of the SSR mixed core operation numerous neutronic calculations have been performed. This paper presents some of the results of those calculations.

  2. Energy access and transition to cleaner cooking fuels and technologies in Sri Lanka: Issues and policy limitations

    Easy energy access is a trigger for human, social, and economic development. A research project was undertaken in Sri Lanka to broaden the understanding of human dimension of energy access and technologies. A questionnaire survey, covering 2269 households, gathered data on socio-economic contexts and issues influencing a transition towards clean cooking facilities. The findings reveal that the transition is impeded by four factors: the lack of motivation and the pressure for switching over to cleaner facilities, the lack of modern energy technology options, the financial risks, and the lack of financing and other support. The paper describes the delicate two-way interrelation between women earning wages and the transitions to cleaner cooking fuels and technologies. The findings suggest the need for a policy framework involving the stakeholders, financing and standardised technologies. To make a change it is proposed to introduce a national, integrated policy incorporating financing and energy governance. - Highlights: ► Households in Sri Lanka lack access to modern energy technology options for cooking. ► Cooking with fuel wood and residues is the norm in Sri Lanka, particularly in rural households. ► A survey of rural households revealed that most cannot afford to switch to cleaner cooking options. ► Most households have little awareness of the health impacts of biomass cooking. ► Women in regular formal employment are more likely to value cleaner cooking options that save time.

  3. Nuclear structure of $^{231}$Ac

    Boutami, R; Mach, H; Kurcewicz, W; Fraile, L M; Gulda, K; Aas, A J; García-Raffi, L M; Løvhøiden, G; Martínez, T; Rubio, B; Taín, J L; Tengblad, O

    2008-01-01

    The low-energy structure of 231Ac has been investigated by means of gamma ray spectroscopy following the beta-decay of 231Ra. Multipolarities of 28 transitions have been established by measuring conversion electrons with a mini-orange electron spectrometer. The decay scheme of 231Ra --> 231Ac has been constructed for the first time. The Advanced Time Delayed beta-gamma-gamma(t) method has been used to measure the half-lives of five levels. The moderately fast B(E1) transition rates derived suggest that the octupole effects, albeit weak, are still present in this exotic nucleus.

  4. Fuel Pellets from Wheat Straw: The Effect of Lignin Glass Transition and Surface Waxes on Pelletizing Properties

    Stelte, Wolfgang; Clemons, Craig; Holm, Jens K.;

    2012-01-01

    The utilization of wheat straw as a renewable energy resource is limited due to its low bulk density. Pelletizing wheat straw into fuel pellets of high density increases its handling properties but is more challenging compared to pelletizing woody biomass. Straw has a lower lignin content and a...... high concentration of hydrophobic waxes on its outer surface that may limit the pellet strength. The present work studies the impact of the lignin glass transition on the pelletizing properties of wheat straw. Furthermore, the effect of surface waxes on the pelletizing process and pellet strength are...... effect is observed at elevated temperatures. Fuel pellets made from extracted wheat straw have a slightly higher compression strength which might be explained by a better interparticle adhesion in the absence of hydrophobic surface waxes....

  5. Transition core DNBR penalty determination for Angra-1 nuclear power plant mixed cores consisting of standard and advanced fuel assemblies

    When two (or more) types of Fuel Assemblies (FA) are inserted in a nuclear reactor core, a flow redistribution occurs, due to the different hydraulic resistances of these assemblies. This way, the FA's with higher hydraulic resistance will get a Departure from Nucleate Boiling Ratio (DNBR) penalty since a part of the total flow will diverge to the FA's with lower hydraulic resistance. Regarding Angra-1 Nuclear Power Plant (NPP), it is planned in a next cycle to insert a new Advanced FA that is a result from a joint-venture project of the companies INB - Industrias Nucleares do Brasil, WEC - Westinghouse Electric Company and KNF - Korean Nuclear Fuel. Therefore, the purpose of this article is to show the work done to determine the DNBR penalty to be applied to the Advanced FA's present in a mixed (or transition) core consisting of Advanced and Standard FA's. (author)

  6. Heating of the fuel mixture due to viscous stress ahead of accelerating flames in deflagration-to-detonation transition

    Valiev, Damir; Akkerman, V'yacheslav; Eriksson, Lars-Erik; Marklund, Mattias

    2008-01-01

    The role of viscous stress in heating of the fuel mixture in deflagration-to-detonation transition in tubes is studied both analytically and numerically. The analytical theory is developed in the limit of low Mach number; it determines temperature distribution ahead of an accelerating flame with maximum achieved at the walls. The heating effects of viscous stress and the compression wave become comparable at sufficiently high values of the Mach number. In the case of relatively large Mach number, viscous heating is investigated by direct numerical simulations. The simulations were performed on the basis of compressible Navier-Stokes gas-dynamic equations taking into account chemical kinetics. In agreement with the theory, viscous stress makes heating and explosion of the fuel mixture preferential at the walls. The explosion develops in an essentially multi-dimensional way, with fast spontaneous reaction spreading along the walls and pushing inclined shocks. Eventually, the combination of explosive reaction an...

  7. Fast breeder reactor core concept consistent with fuel cycle system during the transition period from LWR to FBR cycles in Japan

    During the transition period from the LWR cycle to a FBR cycle, the Pu needed for FBR start-up will be obtained from the next reprocessing facility. Therefore, from the economic viewpoint, it would be better if the FBR core in the next reprocessing facility had a lower Pu inventory. A design concept study was carried out for an FBR core with a lower Pu inventory that is consistent with the fuel cycle system during the transition period. The Pu from LWR spent fuel will be used for FBR start-up at least for the initial core cycle and succeeding first few cycles during the transition period. An FBR core loaded with Pu from LWR spent fuel has higher burnup reactivity than one loaded with Pu from FBR multi-recycling fuel composition. The increased burnup reactivity may reduce the cycle length of the FBR core. We chose loading of minor actinides (MAs) into the FBR MOX fuel as the countermeasure to the increased burnup reactivity from the viewpoint of utilizing nuclear characteristics of the MAs. The maximum MA content in the MOX fuel was set to 5% on the basis of irradiation test results. MAs recovered from the LWR spent fuel that provides Pu for FBR start-up are loaded into the initial loading fuel assemblies and exchanged fuel assemblies for several cycles until equilibriumis reached. The average MA content of the initially loaded fuel was assumed to be 3%, and that of the exchanged fuel was assumed to be 5%. The core performance including burnup characteristics and reactivity coefficient were also evaluated, and it was confirmed that the transient core from the initial loading until the equilibrium cycle for loaded Pu from LWR spent fuels could maintain performance neary equal to that of an FBR multi-recycling core. (author)

  8. Synthesis and phase transition of Li-Mn-O spinels with high Li/Mn ratio by thermo-decomposition of LiMnC2O4(Ac)

    LiMnC2O4(Ac) precursor in which Li+ and Mn2+ were amalgamated in one molecule was prepared by solid-state reaction at room-temperature using manganese acetate, lithium hydroxide and oxalic acid as raw materials. By thermo-decomposition of LiMnC2O4(Ac) at various temperatures, a series of Li1+y[Mn2-xLix]16dO4 spinels were prepared with Li2MnO3 as impurities. The structure and phase transition of these spinels were investigated by XRD, TG/DTA, average oxidation state of Mn and cyclic voltammeric techniques. Results revealed that the Li-Mn-O spinels with high Li/Mn ratio were unstable at high temperature, and the phase transition was associated with the transfer of Li+ from octahedral 16c sites to 16d sites. With the sintering temperature increasing from 450 to 850 deg. C, the phase structure varied from lithiated-spinel Li2Mn2O4 to Li4Mn5O12-like to LiMn2O4-like and finally to rock-salt LiMnO2-like. A way of determining x with average oxidation state of Mn and the content of Li2MnO3 was also demonstrated

  9. Some conditions and prospects of transition to closed fuel cycle in Russia

    Nuclear policy of Russia is based on the necessity of closure of nuclear fuel cycle. But at the same time schedule of such a going is not defined. In this study some conditions and possible time-frames of going the nuclear fuel cycle of Russia to closure are discussed. Naturally, the main condition is revival of Russian economy wherein nuclear power will turn to be necessary in a number of Russian regions. But the question is whether closure of nuclear cycle strategy will be implemented in the near future or nuclear power will develop based on open fuel cycle over a long period of time? at present economic circumstances in Russia has formed in such a way that economics of current projects is not favourable to going to closure of cycle due to high capital investment cost and low fuel component of costs, due to low cost of natural uranium. Ecological analysis performed within the framework of external cost model also does not suggest that closed cycle has essential advantages at present, but also in sight. The authors have considered a model including not only external costs but also total resources expenditures with long-term power development. In the framework of such a method it can be demonstrated that closed fuel cycle has some important advantages taking into account not only tasks of immediate future, but power development strategy for the period of 30-50 years. Under conditions of nuclear capacities increase (to 30-50 GW) limitation of cheap uranium resources available in Russia will assume a new significance. Approach of prices at the back-end stages of nuclear fuel cycle to West Europe level also will favour to going to a closed fuel cycle. More severe ecological requirements answering to a sustainable development concept also will make a contribution. Closure of fuel cycle can be significantly accelerated in the case of implementation of weapon plutonium utilization program. The factors mentioned above facilitate evenly to going to a closed nuclear fuel

  10. Climate and Fuel Controls on North American Paleofires: Smoldering to Flaming in the Late-glacial-Holocene Transition

    Han, Y. M.; Peteet, D. M.; Arimoto, R.; Cao, J. J.; An, Z. S.; Sritrairat, S.; Yan, B. Z.

    2016-02-01

    Smoldering and flaming fires, which emit different proportions of organic (OC) and black carbon (BC, in the form of char and soot), have long been recognized in modern wildfire observations but never in a paleo-record, and little is known about their interactions with climate. Here we show that in the late glacial-early Holocene transition period, when the climate was moist, relatively high quantities of char were deposited in Linsley Pond, Connecticut, USA while soot was more abundant during the warmer and drier early Holocene interval. The highest soot mass accumulation rates (MARs) occurred at the beginning of the Holocene as fuel availability increased through the climatic transition when boreal forests were locally extirpated. These variations with time are related to the different formation pathways of char and soot, which are governed by combustion efficiency. This study provides an approach for differentiating smoldering from flaming combustion in paleo-wildfire reconstructions. Our results suggest that climate and fuel loads control the occurrence of different wildfire types and precipitation may play a key role.

  11. Dynamics and ferroelectric phase transition of (C3N2H5)5Bi2Br11 by means of ac calorimetry and 1H NMR relaxometry

    Przesławski, J.; Medycki, W.; Piecha, A.; Jakubas, R.; Kruk, D.

    2013-01-01

    A quite uncommon type of heat anomaly has been disclosed by calorimetric experiments in ferroelectric crystal (C3N2H5)5Bi2Br11 close to the paraelectric-ferroelectric transition. Thermal parameters (such as the excess enthalpy (ΔH) and the excess entropy (ΔS)) of the continuous ferroelectric phase transition at ca. 155 K have been estimated and discussed. The entropy transition accompanying the ferroelectric phase transition (PT) of the order of 35 J/mol K confirms an 'order-disorder' mechanism. The ferroelectric-paraelectric PT has been described by the Landau model using the specific heat data.1H spin-lattice relaxation at 25 MHz has been measured for this crystal in a very broad temperature range 90-420 K, covering two phase transitions (at 155 and 355 K). The relaxation data have been interpreted in terms of different dynamical properties of imidazolium cations put in structurally different environments.

  12. 78 FR 29519 - Physical Protection of Irradiated Reactor Fuel in Transit

    2013-05-20

    ... shipments of naval SNF under the Naval Nuclear Propulsion Program and highway shipment of classified... Measures for the Transportation of Spent Nuclear Fuel Greater than 100 Grams,'' (67 FR 63167; October 10... Register (44 FR 34466) an interim final rule that established requirements for the physical protection...

  13. Phase transition between the Bragg Glass and a disordered Phase in Nb3Sn, detected by 3rd harmonics of the AC magnetic susceptibility

    Adesso, Maria G.; Uglietti, Davide; Flukiger, Rene; Polichetti, Massimiliano; Pace, Sandro

    2005-01-01

    We report additional experimental evidences about the presence of an universal behavior in the Field-Temperature Phase Diagram of Type II Superconductors. This behavior is characterized by a phase transition in the vortex matter between the disordered and the Bragg Glass phase. The experimental detection of a Peak Effect phenomenon has been proved to be strictly connected to the existence of this phase transition. In this paper, we show the first observation of a Peak Effect in the compound N...

  14. Dynamics and ferroelectric phase transition of (C3N2H5)5Bi2Br11 by means of ac calorimetry and 1H NMR relaxometry

    Highlights: ► The excess entropy clearly confirms an ‘order–disorder’ mechanism assigned to the dynamics of the imidazolium cations. ► 1H NMR conformed dynamical heterogeneity of the imidazolium cations in low temperature phases. ► The paraelectric-ferroelectric transition at 155 K is close to the tricritical one. -- Abstract: A quite uncommon type of heat anomaly has been disclosed by calorimetric experiments in ferroelectric crystal (C3N2H5)5Bi2Br11 close to the paraelectric-ferroelectric transition. Thermal parameters (such as the excess enthalpy (ΔH) and the excess entropy (ΔS)) of the continuous ferroelectric phase transition at ca. 155 K have been estimated and discussed. The entropy transition accompanying the ferroelectric phase transition (PT) of the order of 35 J/mol K confirms an ‘order–disorder’ mechanism. The ferroelectric–paraelectric PT has been described by the Landau model using the specific heat data.1H spin–lattice relaxation at 25 MHz has been measured for this crystal in a very broad temperature range 90–420 K, covering two phase transitions (at 155 and 355 K). The relaxation data have been interpreted in terms of different dynamical properties of imidazolium cations put in structurally different environments.

  15. Optimization of fuel cell membrane electrode assemblies for transition metal ion-chelating ordered mesoporous carbon cathode catalysts

    Johanna K. Dombrovskis

    2014-12-01

    Full Text Available Transition metal ion-chelating ordered mesoporous carbon (TM-OMC materials were recently shown to be efficient polymer electrolyte membrane fuel cell (PEMFC catalysts. The structure and properties of these catalysts are largely different from conventional catalyst materials, thus rendering membrane electrode assembly (MEA preparation parameters developed for conventional catalysts not useful for applications of TM-OMC catalysts. This necessitates development of a methodology to incorporate TM-OMC catalysts in the MEA. Here, an efficient method for MEA preparation using TM-OMC catalyst materials for PEMFC is developed including effects of catalyst/ionomer loading and catalyst/ionomer-mixing and application procedures. An optimized protocol for MEA preparation using TM-OMC catalysts is described.

  16. Optimization of fuel cell membrane electrode assemblies for transition metal ion-chelating ordered mesoporous carbon cathode catalysts a

    Dombrovskis, Johanna K.; Prestel, Cathrin; Palmqvist, Anders E. C.

    2014-12-01

    Transition metal ion-chelating ordered mesoporous carbon (TM-OMC) materials were recently shown to be efficient polymer electrolyte membrane fuel cell (PEMFC) catalysts. The structure and properties of these catalysts are largely different from conventional catalyst materials, thus rendering membrane electrode assembly (MEA) preparation parameters developed for conventional catalysts not useful for applications of TM-OMC catalysts. This necessitates development of a methodology to incorporate TM-OMC catalysts in the MEA. Here, an efficient method for MEA preparation using TM-OMC catalyst materials for PEMFC is developed including effects of catalyst/ionomer loading and catalyst/ionomer-mixing and application procedures. An optimized protocol for MEA preparation using TM-OMC catalysts is described.

  17. Fire Behavior Modeling - Experiment on Surface Fire Transition to the Elevated Live Fuel

    Omodan, Sunday

    2015-01-01

    ABSTRCT OF THE THESISFire Behavior Modeling - Experiment on Surface Fire Transition to the Elevated Live Fuelby Sunday OmodanMaster of Science, Graduate Program in Mechanical EngineeringUniversity of California, Riverside, June 2015Dr. Marko Princevac, ChairpersonRecent increase in the number of wildfires globally over the last decade has made fire behavior modelling a major subject of scientific concern. Although, there have been wildfire studies since the beginning of 19th century, and thi...

  18. Zero Emission Bay Area (ZEBA) Fuel Cell Bus Demonstration: First Results Report

    Chandler, K.; Eudy, L.

    2011-08-01

    This report documents the early implementation experience for the Zero Emission Bay Area (ZEBA) Demonstration, the largest fleet of fuel cell buses in the United States. The ZEBA Demonstration group includes five participating transit agencies: AC Transit (lead transit agency), Santa Clara Valley Transportation Authority (VTA), Golden Gate Transit (GGT), San Mateo County Transit District (SamTrans), and San Francisco Municipal Railway (Muni). The ZEBA partners are collaborating with the U.S. Department of Energy (DOE) and DOE's National Renewable Energy Laboratory (NREL) to evaluate the buses in revenue service.

  19. Zero Emission Bay Area (ZEBA) Fuel Cell Bus Demonstration Results: Fifth Report

    Eudy, Leslie [National Renewable Energy Lab. (NREL), Golden, CO (United States); Post, Matthew [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jeffers, Matthew [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-06-01

    This report presents results of a demonstration of fuel cell electric buses (FCEB) operating in Oakland, California. Alameda-Contra Costa Transit District (AC Transit) leads the Zero Emission Bay Area (ZEBA) demonstration, which includes 13 advanced-design fuel cell buses and two hydrogen fueling stations. The ZEBA partners are collaborating with the U.S. Department of Energy (DOE) and DOE's National Renewable Energy Laboratory (NREL) to evaluate the buses in revenue service. NREL has published four previous reports describing operation of these buses. This report presents new and updated results covering data from January 2015 through December 2015.

  20. Mechanisms of disease: epithelial-mesenchymal transition and back again: does cellular plasticity fuel neoplastic progression?

    Bissell, Mina J; Turley, Eva A.; Veiseh, Mandana; Radisky, Derek C.; Bissell, Mina J.

    2008-02-13

    Epithelial-mesenchymal transition (EMT) is a conversion that facilitates organ morphogenesis and tissue remodeling in physiological processes such as embryonic development and wound healing. A similar phenotypic conversion is also detected in fibrotic diseases and neoplasia, which is associated with disease progression. EMT in cancer epithelial cells often seems to be an incomplete and bi-directional process. In this Review, we discuss the phenomenon of EMT as it pertains to tumor development, focusing on exceptions to the commonly held rule that EMT promotes invasion and metastasis. We also highlight the role of the RAS-controlled signaling mediators, ERK1, ERK2 and PI3-kinase, as microenvironmental responsive regulators of EMT.

  1. Sub-Doppler Spectra of Infrared Hyperfine Transitions of Nitric Oxide Using a Pulse Modulated Quantum Cascade Laser: Rapid Passage, Free Induction Decay and the AC Stark Effect

    Duxbury, Geoffrey; Kelly, James F.; Blake, Thomas A.; Langford, Nigel

    2012-05-07

    Using a low power, rapid (nsec) pulse-modulated quantum cascade (QC) laser, collective coherent effects in the 5 {micro}m spectrum of nitric oxide have been demonstrated by the observation of sub-Doppler hyperfine splitting and also Autler-Townes splitting of Doppler broadened lines. For nitrous oxide, experiments and model calculations have demonstrated that two main effects occur with ulsemodulated (chirped) quantum cascade lasers: free induction decay signals, and signals induced by rapid passage during the laser chirp. In the open shell molecule, NO, in which both {Lambda}-doubling splitting and hyperfine structure occur, laser field-induced coupling between the hyperfine levels of the two {Lambda}-doublet components can induce a large AC Stark effect. This may be observed as sub-Doppler structure, field-induced splittings, or Autler-Townes splitting of a Doppler broadened line. These represent an extension of the types of behaviour observed in the closed shell molecule nitrous oxide, using the same apparatus, when probed with an 8 {micro}m QC laser.

  2. Fuel fabrication processes, design and experimental conditions for the joint US-Swiss mixed carbide test in FFTF (AC-3 test)

    The preparation of mixed carbide fuel for a joint (US-Swiss) irradiation test in the US Fast Flux Test Facility (FFTF) is described, together with the experiment design and the irradiation conditions. Two fabrication routes were compared. The US produced 66 fuel pins containing pellet fuel via the powder-pellet (dry) route, and the Swiss group produced 25 sphere pac pins of mixed carbide using the internal gelation (wet) route. Both sets of fuel met all t the requirements of the specifications concerning soichiometry, chemical composition and structure. The pin designs were as similar as possible. The test operated successfully in the FFTF for 620 effective full power days until October 1988 and reached over 8% burn up with peak powers of around 80 kW/m. The conclusions were that the choice of sphere pac or pellet fuel for reactor application is dependent on preferred differences in fabrication (e.g. economics and environmental factors) and not on differences in irradiation behaviour. (orig.)

  3. Durable transition-metal-carbide-supported Pt-Ru anodes for direct methanol fuel cells

    Nishanth, K.G.; Sridhar, P.; Pitchumani, S. [CSIR-Central Electrochemical Research Institute, Madras Unit, CSIR Madras Complex, Chennai (India); Shukla, A.K. [Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore (India)

    2012-02-15

    Molybdenum carbide (MoC) and tungsten carbide (WC) are synthesized by direct carbonization method. Pt-Ru catalysts supported on MoC, WC, and Vulcan XC-72R are prepared, and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy in conjunction with electrochemistry. Electrochemical activities for the catalysts towards methanol electro-oxidation are studied by cyclic voltammetry. All the electro-catalysts are subjected to accelerated durability test (ADT). The electrochemical activity of carbide-supported electro-catalysts towards methanol electro-oxidation is found to be higher than carbon-supported catalysts before and after ADT. The study suggests that Pt-Ru/MoC and Pt-Ru/WC catalysts are more durable than Pt-Ru/C. Direct methanol fuel cells (DMFCs) with Pt-Ru/MoC and Pt-Ru/WC anodes also exhibit higher performance than the DMFC with Pt-Ru/C anode. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Star-Forming Brightest Cluster Galaxies at 0.25 < z < 1.25: A Transitioning Fuel Supply

    McDonald, M.; Stalder, B.; Bayliss, M.; Allen, S. W.; Applegate, D. E.; Ashby, M. L. N.; Bautz, M.; Benson, B. A.; Bleem, L. E.; Brodwin, M.; Carlstrom, J. E.

    2016-02-01

    We present a multi-wavelength study of 90 brightest cluster galaxies (BCGs) in a sample of galaxy clusters selected via the Sunyaev Zel'dovich effect by the South Pole Telescope, utilizing data from various ground- and space-based facilities. We infer the star formation rate (SFR) for the BCG in each cluster, based on the UV and IR continuum luminosity, as well as the [O II] emission line luminosity in cases where spectroscopy is available, finding 7 systems with SFR > 100 Msun/yr. We find that the BCG SFR exceeds 10 Msun/yr in 31 of 90 (34%) cases at 0.25 < z < 1.25, compared to ~1-5% at z ~ 0 from the literature. At z > 1, this fraction increases to 92(+6)(-31)%, implying a steady decrease in the BCG SFR over the past ~9 Gyr. At low-z, we find that the specific star formation rate in BCGs is declining more slowly with time than for field or cluster galaxies, most likely due to the replenishing fuel from the cooling ICM in relaxed, cool core clusters. At z > 0.6, the correlation between cluster central entropy and BCG star formation - which is well established at z ~ 0 - is not present. Instead, we find that the most star-forming BCGs at high-z are found in the cores of dynamically unrelaxed clusters. We investigate the rest-frame near-UV morphology of a subsample of the most star-forming BCGs using data from the Hubble Space Telescope, finding complex, highly asymmetric UV morphologies on scales as large as ~50-60 kpc. The high fraction of star-forming BCGs hosted in unrelaxed, non-cool core clusters at early times suggests that the dominant mode of fueling star formation in BCGs may have recently transitioned from galaxy-galaxy interactions to ICM cooling.

  5. High performance ceramic interconnect material for solid oxide fuel cells (SOFCs): Ca- and transition metal-doped yttrium chromite

    Yoon, Kyung Joong; Stevenson, Jeffrey W.; Marina, Olga A.

    2011-10-01

    The effect of transition metal substitution on thermal and electrical properties of Ca-doped yttrium chromite was investigated in relation to use as a ceramic interconnect in high temperature solid oxide fuel cells (SOFCs). 10 at.% Co, 4 at.% Ni, and 1 at.% Cu substitution on B-site of 20 at.% Ca-doped yttrium chromite led to a close match of thermal expansion coefficient (TEC) with that of 8 mol% yttria-stabilized zirconia (YSZ), and a single phase Y0.8Ca0.2Cr0.85Co0.1Ni0.04Cu0.01O3 remained stable between 25 and 1100 °C over a wide oxygen partial pressure range. Doping with Cu significantly facilitated densification of yttrium chromite. Ni dopant improved both electrical conductivity and dimensional stability in reducing environments, likely through diminishing the oxygen vacancy formation. Substitution with Co substantially enhanced electrical conductivity in oxidizing atmosphere, which was attributed to an increase in charge carrier density and hopping mobility. Electrical conductivity of Y0.8Ca0.2Cr0.85Co0.1Ni0.04Cu0.01O3 at 900 °C is 57 S cm-1 in air and 11 S cm-1 in fuel (pO2 = 5 × 10-17 atm) environments. Chemical compatibility of doped yttrium chromite with other cell components was verified at the processing temperatures. Based on the chemical and dimensional stability, sinterability, and thermal and electrical properties, Y0.8Ca0.2Cr0.85Co0.1Ni0.04Cu0.01O3 is suggested as a promising SOFC ceramic interconnect to potentially overcome technical limitations of conventional acceptor-doped lanthanum chromites.

  6. Star-forming Brightest Cluster Galaxies at 0.25 > z > 1.25: A Transitioning Fuel Supply

    McDonald, M.; Stalder, B.; Bayliss, M.; Allen, S. W.; Applegate, D. E.; Ashby, M. L. N.; Bautz, M.; Benson, B. A.; Bleem, L. E.; Brodwin, M.; Carlstrom, J. E.; Chiu, I.; Desai, S.; Gonzalez, A. H.; Hlavacek-Larrondo, J.; Holzapfel, W. L.; Marrone, D. P.; Miller, E. D.; Reichardt, C. L.; Saliwanchik, B. R.; Saro, A.; Schrabback, T.; Stanford, S. A.; Stark, A. A.; Vieira, J. D.; Zenteno, A.

    2016-02-01

    We present a multiwavelength study of the 90 brightest cluster galaxies (BCGs) in a sample of galaxy clusters selected via the Sunyaev Zel’dovich effect by the South Pole Telescope, utilizing data from various ground- and space-based facilities. We infer the star-formation rate (SFR) for the BCG in each cluster—based on the UV and IR continuum luminosity, as well as the [O ii]λλ3726,3729 emission line luminosity in cases where spectroscopy is available—and find seven systems with SFR > 100 M⊙ yr-1. We find that the BCG SFR exceeds 10 M⊙ yr-1 in 31 of 90 (34%) cases at 0.25 BCG SFR over the past ˜9 Gyr. At low-z, we find that the specific SFR in BCGs is declining more slowly with time than for field or cluster galaxies, which is most likely due to the replenishing fuel from the cooling ICM in relaxed, cool core clusters. At z ≳ 0.6, the correlation between the cluster central entropy and BCG star formation—which is well established at z ˜ 0—is not present. Instead, we find that the most star-forming BCGs at high-z are found in the cores of dynamically unrelaxed clusters. We use data from the Hubble Space Telescope to investigate the rest-frame near-UV morphology of a subsample of the most star-forming BCGs, and find complex, highly asymmetric UV morphologies on scales as large as ˜50-60 kpc. The high fraction of star-forming BCGs hosted in unrelaxed, non-cool core clusters at early times suggests that the dominant mode of fueling star formation in BCGs may have recently transitioned from galaxy-galaxy interactions to ICM cooling.

  7. Dynamic Thermal Loads and Cooling Requirements Calculations for V ACs System in Nuclear Fuel Processing Facilities Using Computer Aided Energy Conservation Models

    In terms of nuclear safety, the most important function of ventilation air conditioning (VAC) systems is to maintain safe ambient conditions for components and structures important to safety inside the nuclear facility and to maintain appropriate working conditions for the plant's operating and maintenance staff. As a part of a study aimed to evaluate the performance of VAC system of the nuclear fuel cycle facility (NFCF) a computer model was developed and verified to evaluate the thermal loads and cooling requirements for different zones of fuel processing facility. The program is based on transfer function method (TFM) and it is used to calculate the dynamic heat gain by various multilayer walls constructions and windows hour by hour at any orientation of the building. The developed model was verified by comparing the obtained calculated results of the solar heat gain by a given building with the corresponding calculated values using finite difference method (FDM) and total equivalent temperature different method (TETD). As an example the developed program is used to calculate the cooling loads of the different zones of a typical nuclear fuel facility the results showed that the cooling capacities of the different cooling units of each zone of the facility meet the design requirements according to safety regulations in nuclear facilities.

  8. Hydrogen and Fuel Cell Transit Bus Evaluations: Joint Evaluation Plan for the U.S. Department of Energy and the Federal Transit Administration (Report and Appendix)

    Eudy, L.; Chandler, K.

    2008-05-01

    This document describes the hydrogen transit bus evaluations performed by the National Renewable Energy Laboratory (NREL) and funded by the U.S. Department of Energy (DOE) and the U.S. Department of Transportation's Federal Transit Administration (FTA).

  9. Investigation of structural and chemical transitions in copper oxide microstructures produced by combustion waves in a mixture of CuO-Cu2O-Cu and fuel

    Hwang, Hayoung; Lee, Kang Yeol; Yeo, Taehan; Choi, Wonjoon

    2015-12-01

    The application of micro/nanostructured materials to combustion enables distinctive chemical reactions that can be used to modulate the reaction rates. Simultaneously, combustion is capable of changing the intrinsic properties of micro/nanostructured materials based on chemical interactions in high-temperature conditions. In this work, we investigate the structural-chemical transition of copper oxide microstructures exposed to interfacially driven combustion waves. The high thermal energy and exchange of chemical compounds resulting from the instant combustion waves cause direct transition without any further processes. The precise characterization of the structural and chemical transitions in the copper oxide microstructures and chemical fuels confirm that the self-propagating combustion waves in the layered composites of Cu/Cu2O/CuO microparticle-based films and the chemical fuel layers yield the direct synthesis of Cu(OH)2 flower-like structures and nanowires. The propagation of combustion waves at the interface induces an increase of the surface temperatures over 650 °C and the direct interaction between the copper oxide and chemical compounds of the fuel layers. Further application of these interfacially driven combustion waves will contribute to the development of one-step, fast, low-cost methods for the synthesis of micro/nanostructured materials.

  10. Oxygen starvation induced cell potential decline and corresponding operating state transitions of a direct methanol fuel cell in galvanostatic regime

    Graphical abstract: - Highlights: • A DMFC converts from current reversal to cell potential reversal with reduced air flow. • Operation state transitions can be indicated by the cell potential decline. • Voltage variation with oxygen stoichiometry is characterized into three stages. • Existence of high localized anode potential leads to Ru dissolution. - Abstract: Air maldistribution is frequently encountered in direct methanol fuel cell (DMFC) stacks. To understand the characteristics of different single cells at air maldistribution, the effect of the oxygen stoichiometry (OS) on the behavior of a single DMFC in galvanostatic operation is investigated both experimentally and numerically. Special attention is paid to the cell potential dependence on the OS, based on which the OS is characterized into three distinct ranges. The cell potential varies little in range 1, but decreases dramatically with the OS in range 2, and becomes negative in range 3. The cell characteristics in each range are highlighted in detail. The entire cell acts as a normal DMFC in range 1, but turns to bi-functional mode in range 2 with parasitic hydrogen evolution from the negative electrode (NE) due to partial oxygen depletion. Extremely high current density arises near the air inlet when the cell potential approaches zero, which can lead to high electrode potential in the NE and induce serious ruthenium dissolution. When the OS decreases further to range 3, hydrogen evolution starts to occur in the positive electrode (PE), and the evolved hydrogen can be re-oxidized upstream, leading to coexistence of four electrochemical half-reactions in the PE

  11. ACAC Converters for UPS

    Rusalin Lucian R. Păun

    2008-05-01

    Full Text Available This paper propose a new control technique forsingle – phase ACAC converters used for a on-line UPSwith a good dynamic response, a reduced-partscomponents, a good output characteristic, a good powerfactorcorrection(PFC. This converter no needs anisolation transformer. A power factor correction rectifierand an inverter with the proposed control scheme has beendesigned and simulated using Caspoc2007, validating theconcept.

  12. GRID-CONNECTECD DOUBLE-STAGE AC-AC POWER CONVERTER FOR CSP RENEWABLE ENERGY SYSTEMS

    Sorrentino, Vincenzo

    2015-01-01

    In the last years the renewable energy sources have known a state of their advanced diffusion considering their advantages compared to the traditional energy sources like fossil fuels. For this reason the combined heat and power (CHP) plant fueled by renewable sources are widely used. The purpose of this Ph.D. thesis is the design of a new Grid-connected Double-Stage AC-DC/DC-AC Power Converter (DSACPC) for a Concentrating Solar plant for Combined generation of Heat and Power (CS-CHP), th...

  13. Transition from non-renewable to renewable energy sources: fuel cells in Antarctica as an economically attractive niche

    There is a growing amount of evidence that indicates that fuel cells might be commercially attractive in several market niches in Latin America; however, political approval of demonstration projects has been elusive. In this paper, the results of an economic study carried out on the assumption of introducing an environmentally friendly fuel, such as methanol, for feeding fuel cell systems for electricity generation and heat production in the six bases that Argentina has in Antarctica are reported. It is seen that, in this particular case, there is a net cost benefit, even if the assets resulting from diminishing pollution in Antarctica are not taken into account. (Author)

  14. Analysis of the Transition to Hydrogen Fuel Cell Vehicles and the Potential Hydrogen Energy Infrastructure Requirements, March 2008

    Greene, David L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Leiby, Paul N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); James, Brian [Directed Technologies, Inc., Youngstown, OH (United States); Perez, Julie [Directed Technologies, Inc., Youngstown, OH (United States); Melendez, Margo [National Renewable Energy Lab. (NREL), Golden, CO (United States); Milbrandt, Anelia [National Renewable Energy Lab. (NREL), Golden, CO (United States); Unnash, Stefan [Life Cycle Associates, Portola Valley, CA (United States); Rutherford, Daniel [Life Cycle Associates, Portola Valley, CA (United States); Hooks, Matthew [TIAX, LLC, Lexingtion, MA (United States)

    2008-03-14

    Achieving a successful transition to hydrogen-powered vehicles in the U.S. automotive market will require strong and sustained commitment by hydrogen producers, vehicle manufacturers, transporters and retailers, consumers, and governments. The interaction of these agents in the marketplace will determine the real costs and benefits of early market transformation policies, and ultimately the success of the transition itself.

  15. Contribution to the study of 233U production with MOX-ThPu fuel in PWR reactor. Transition scenarios towards Th/233U iso-generating concepts in thermal spectrum. Development of the MURE fuel evolution code

    If nuclear power is to provide a significant fraction of the growing world energy demand, only through the breeding concept can the development of sustainable nuclear energy become a reality. The study of such a transition, from present-day nuclear technologies to future breeding concepts is therefore pertinent. Among these future concepts, those using the thorium cycle Th/U-233 in a thermal neutron spectrum are of particular interest; molten-salt type thermal reactors would allow for breeding while requiring comparatively low initial inventories of U-233. The upstream production of U-233 can be obtained through the use of thorium-plutonium mixed oxide fuel in present-day light water reactors. This work presents, firstly, the development of the MURE evolution code system, a C++ object-oriented code that allows the study, through Monte Carlo (M.C.) simulation, of nuclear reactors and the evolution of their fuel under neutron irradiation. The M.C. methods are well-suited for the study of any reactor, whether it'd be an existing reactor using a new kind of fuel or a future concept altogether, the simulation is only dependent on nuclear data. Exact and complex geometries can be simulated and continuous energy particle transport is performed. MURE is an interface with MCNP, the well-known and validated transport code, that allows, among other functionalities, to simulate constant power and constant reactivity evolutions. Secondly, the study of MOX ThPu fuel in a conventional light water reactor (REP) is presented; it explores different plutonium concentrations and isotopic qualities in order to evaluate their safety characteristics. Simulation of their evolution allows us to quantify the production of U-233 at the end of burnup. Last, different french scenarios validating a possible transition towards a park of thermal Th/U-233 breeders, are presented. In these scenarios, U-233 is produced in ThPu moxed light water reactors. (author)

  16. Electrochemical study of lithiated transition metal oxide composite as symmetrical electrode for low temperature ceramic fuel cells

    Fan, Liangdong; Zhang, Hongjuan; Chen, Mingming; Wang, Chengyang; Wang, Hao; Singh, Manish; Zhu, Bin

    2013-01-01

    In this work, Lithiated NiCuZnOx (LNCZO) composite is synthesized and evaluated as a potential symmetrical electrode for ceria-carbonate composite electrolyte based low temperature ceramic fuel cells. Its crystal structures, the hydrogen oxidation/oxygen reduction electrochemical activities and fuel cell performances are systematically examined on the symmetrical cell configuration. Nano crystallite particles in the form of composite are observed for these oxides. The LNCZO shows relatively h...

  17. Hydrogen Scenario Analysis Summary Report: Analysis of the Transition to Hydrogen Fuel Cell Vehicles and the Potential Hydrogen Energy Infrastructure Requirements

    Greene, David L [ORNL; Leiby, Paul Newsome [ORNL; James, Brian [Directed Technologies, Inc.; Perez, Julie [Directed Technologies, Inc.; Melendez, Margo [National Renewable Energy Laboratory (NREL); Milbrandt, Anelia [National Renewable Energy Laboratory (NREL); Unnasch, Stefan [Life Cycle Associates; Rutherford, Daniel [TIAX, LLC; Hooks, Matthew [TIAX, LLC

    2008-03-01

    Achieving a successful transition to hydrogen-powered vehicles in the U.S. automotive market will require strong and sustained commitment by hydrogen producers, vehicle manufacturers, transporters and retailers, consumers, and governments. The interaction of these agents in the marketplace will determine the real costs and benefits of early market transformation policies, and ultimately the success of the transition itself. The transition to hydrogen-powered transportation faces imposing economic barriers. The challenges include developing and refining a new and different power-train technology, building a supporting fuel infrastructure, creating a market for new and unfamiliar vehicles, and achieving economies of scale in vehicle production while providing an attractive selection of vehicle makes and models for car-buyers. The upfront costs will be high and could persist for a decade or more, delaying profitability until an adequate number of vehicles can be produced and moved into consumer markets. However, the potential rewards to the economy, environment, and national security are immense. Such a profound market transformation will require careful planning and strong, consistent policy incentives. Section 811 of the Energy Policy Act (EPACT) of 2005, Public Law 109-59 (U.S. House, 2005), calls for a report from the Secretary of Energy on measures to support the transition to a hydrogen economy. The report was to specifically address production and deployment of hydrogen-fueled vehicles and the hydrogen production and delivery infrastructure needed to support those vehicles. In addition, the 2004 report of the National Academy of Sciences (NAS, 2004), The Hydrogen Economy, contained two recommendations for analyses to be conducted by the U.S. Department of Energy (DOE) to strengthen hydrogen energy transition and infrastructure planning for the hydrogen economy. In response to the EPACT requirement and NAS recommendations, DOE's Hydrogen, Fuel Cells and

  18. Current status of the Japanese nuclear fuel cycle - outline of the Japanese nuclear fuel cycle strategy and transition scenario to FR cycle

    The G8 leaders declared, at the Hokkaido Toyako Summit in 2008, 'to seek to share with all Parties to the UNFCC the vision of, and together with them to consider and adopt in the UNFCCC negotiations, the goal of achieving at least 50% reduction of global emissions by 2050' [1]. They also referred to nuclear energy as 'a means to addressing climate change and energy security concerns and as an essential instrument in reducing dependence on fossil fuels and hence green gas emissions in a growing number of countries.' Japan has been aggressively utilising nuclear energy as one of the major electric power sources to fulfil its domestic energy demand, by currently operating more than 50 nuclear power plants with the total capacity of ca. 50 GWe. This energy source highly depends on the imports of natural uranium from foreign countries to supply fuel to the nuclear power plants. Since nuclear energy use is growing throughout the world; meaning much more uranium resources are to be required in the future, it is rather difficult for Japan alone to maintain the stable supply of uranium resources on a longer-term range. Therefore, the establishment of nuclear fuel cycle with plutonium recycling is indispensable to realise the efficient use of natural uranium resources. Moreover, commercialisation of fast reactors and related fuel cycle (FR cycle) system is aimed at improving drastically the efficiency of natural uranium utilisation and at the same time minimising our environmental concern on geological disposal of high-level radioactive waste. The establishment of closed FR cycle technologies is hoped to secure the long-term sustainable and stable energy supply and to help prevent global warming through reduction of greenhouse gas emissions. This paper describes the current status of nuclear energy and the scenario for the sustainable nuclear energy in Japan. (authors)

  19. AC power supply systems

    An ac power supply system includes a rectifier fed by a normal ac supply, and an inverter connected to the rectifier by a dc link, the inverter being effective to invert the dc output of the receiver at a required frequency to provide an ac output. A dc backup power supply of lower voltage than the normal dc output of the rectifier is connected across the dc link such that the ac output of the rectifier is derived from the backup supply if the voltage of the output of the inverter falls below that of the backup supply. The dc backup power may be derived from a backup ac supply. Use in pumping coolant in nuclear reactor is envisaged. (author)

  20. AcEST: DK950971 [AcEST

    Full Text Available optera acutorost... 37 0.66 tr|B1ACS6|B1ACS6_BALBN DMP1 (Fragment) OS=Balaenoptera ...bonaerens... 37 0.66 tr|B1ACS5|B1ACS5_BALED DMP1 (Fragment) OS=Balaenoptera edeni... GN=... 37 0.66 tr|B1ACS4|B1ACS4_BALBO DMP1 (Fragment) OS=Balaenoptera borealis ... 37 0.66 tr|B1ACS3|B1ACS3..._BALMU DMP1 (Fragment) OS=Balaenoptera musculus ... 37 0.86 tr|B1ACS1|B1ACS1_MEGNO DMP1 (Fragment) OS=Megapt...1ACS2_BALPH DMP1 (Fragment) OS=Balaenoptera physalus ... 37 1.1 tr|B1ACT6|B1ACT6_MESPE DMP1 (Fragment) OS=Me

  1. A Core design study on the fuel displacement options for an effective transition between breakeven and TRU burning fast reactors

    A core design study to convert a breakeven core into a TRU burner is performed for a 600 MWe rated fast reactor. No change in the core and subassembly layouts is assumed, which only allows geometry variations within the fuel rods. Investigated alternatives are to use variable cladding thicknesses, smearing fraction adjustments and annular fuel rod concepts with a central liner of a variable diameter consisting of void, Zr, B4C, Al, W, etc. The variable cladding thickness concept could not be employed due to too high a clad inner wall temperature. A smearing fraction adjustment below a typical fraction of 75% leads to a moderate TRU burning and reduced sodium void worth, but to a relatively high burnup swing. Placing a central non-fuel rod with the fuel arranged in an annular ring affects the core performance and reactivity coefficients, depending on whether it is a moderator or an absorber. In general, candidate materials of high atomic numbers contribute to large positive sodium void worths, but enhanced negative expansion effects. Among the light elements, vanadium reveals a favourable performance with a comparable TRU burning and a reduced sodium void worth, suggesting this material can be regarded as a solid substitute for sodium. (authors)

  2. AC1 Wing

    Adrian DOBRE

    2010-03-01

    Full Text Available The AC1 wing replaces the old wing of the wind tunnel model AEROTAXI, which has been made at scale 1:9. The new wing is part of CESAR program and improves the aerodynamic characteristics of the old one. The geometry of the whole wing was given by FOI Sweden and position of AC1 wing must coincide with the structure of the AEROTAXI model.

  3. AC1 Wing

    Adrian DOBRE

    2010-01-01

    The AC1 wing replaces the old wing of the wind tunnel model AEROTAXI, which has been made at scale 1:9. The new wing is part of CESAR program and improves the aerodynamic characteristics of the old one. The geometry of the whole wing was given by FOI Sweden and position of AC1 wing must coincide with the structure of the AEROTAXI model.

  4. Assessing the potential of fuel saving and emissions reduction of the bus rapid transit system in Curitiba, Brazil

    Dreier, Dennis

    2015-01-01

    The transport sector contributes significantly to global energy use and emissions due to its traditional dependency on fossil fuels. Climate change, security of energy supply and increasing mobility demand is mobilising governments around the challenges of sustainable transport. Immediate opportunities to reduce emissions exist through the adoption of new bus technologies, e.g. advanced powertrains. This thesis analysed energy use and carbon dioxide (CO2) emissions of conventional, hybrid-ele...

  5. Physical characterization of fine particulate matter inside the public transit buses fueled by biodiesel in Toledo, Ohio

    This study presents the physical characteristics of fine particulate matter (PM) collected inside the urban-public transit buses in Toledo, OH. These buses run on 20% biodiesel blended with ultra-low sulfur diesel (ULSD) (B20). For risk analysis, it is crucial to know the modality of the size distribution and the shape factor of PM collected inside the bus. The number-size distribution, microstructure, and aspect ratio of fine PM filter samples collected in the urban-public transit buses were measured for three years (2007-2009), using an environmental scanning electron microscope (ESEM) coupled with energy dispersive X-ray spectrometry (EDX). Only the reproducible results from repeated experiments on ESEM and size distribution obtained by the GRIMM dust monitor were used in this study. The size distribution was found bi-modal in the winter and fall months and was primarily uni-modal during spring and summer. The aspect ratio for different filter samples collected inside the bus range from 2.4 to 3.6 in average value, with standard deviation ranging from 0.9 to 7.4. The square-shaped and oblong-shaped particles represent the single inhalable particle's morphology characteristics in the air of the Toledo transit buses.

  6. The dose to an individual as a result of the incident-free transit of a spent fuel transport vehicle

    Code of Federal Regulations restrictions make it possible to predict the maximum dose equivalent to an individual along the path of a passing spent fuel transport vehicle. These calculations utilize cylindrical geometry and include air attenuation and buildup but neglect individual shielding. The dose equivalents tabulated vary from 1.2 x 10-4 mrem for a transport vehicle moving at 55 mph at a distance of 100 feet to 2.10 x 10-3 mrem for a transport vehicle moving at 10 mph at a distance of 35 feet. The calculations may be duplicated on micro-computer systems. (Auth.)

  7. Transition to hydrogen-based transportation in China: Lessons learned from alternative fuel vehicle programs in the United States and China

    This paper examines the experience of existing alternative fuel vehicle (AFV) programs in the US and China to provide insights into appropriate strategies for developing hydrogen vehicles and infrastructure in China. Although an increasing number of AFVs have been deployed in recent years, various factors have limited this progress, such as large sunk investments in conventional technologies, limited networks of refueling stations, the typically higher cost of AFVs, and the relatively low price of oil. Given these barriers, and additional barriers specific to hydrogen, a transition to hydrogen will be a slow process, and must be supported by both near- and long-term policies that have clear and measurable goals that take hydrogen beyond fleet applications into broader vehicle markets. Because a transition to hydrogen vehicles will not occur quickly, it is necessary for the government to have consistent and integrated transportation policies combining short- and long-term goals. These policies should draw upon resources from both governments and multinational companies to provide incentives for vehicle purchases, promote investment in infrastructure, and disseminate information to raise public awareness. Multinationals may find China to be an ideal testing ground for innovative hydrogen vehicles with appropriate incentive policies and programs

  8. Dynamics of a nanowire superlattice in an ac electric field

    Zhang, Aizhen; Voon, L. C. Lew Yan; M. Willatzen

    2005-01-01

    With a one-band envelope function theory, we investigate the dynamics of a finite nanowire superlattice driven by an ac electric field by solving numerically the time-dependent Schroedinger equation. We find that for an ac electric field resonant with two energy levels located in two different minibands, the coherent dynamics in nanowire superlattices is much more complex as compared to the standard two-level description. Depending on the energy levels involved in the transitions, the coheren...

  9. ac bidirectional motor controller

    Schreiner, K.

    1988-01-01

    Test data are presented and the design of a high-efficiency motor/generator controller at NASA-Lewis for use with the Space Station power system testbed is described. The bidirectional motor driver is a 20 kHz to variable frequency three-phase ac converter that operates from the high-frequency ac bus being designed for the Space Station. A zero-voltage-switching pulse-density-modulation technique is used in the converter to shape the low-frequency output waveform.

  10. Feasibility study of recycle material storage facility in the flexible fuel cycle system during transition from LWR cycle to FBR cycle

    In order to establish the future ideal FBR fuel cycle system from the current LWR fuel cycle, we proposed the Flexible Fuel Cycle Initiative (FFCI) as a suitable transition system. The FFCI removes about 90% of the U present in LWR spent fuel and the residual material, designated as recycle material (RM), is temporarily stored in a facility, such as the vitrified high-level waste (HLW) storage facility. Decay heat of the RM is removed with natural convection of air. In this paper, feasibility of the RM storage facility was studied from viewpoints of heat removal performance and critical safety. Maximum temperature of the RM and the containment pipe were evaluated for the variable density value which depends on the RM filling ratio. Because the heat density of the RM is larger than that of vitrified HLW, we made the diameter of the canister 15cm which is about one third the diameter of a vitrified HLW canister. To improve economy, we evaluated the safety of the storage facility in which three canisters surrounded by an outer pipe identical to the air pipe used in the HLW storage facility. Each canister is surrounded by an containment pipe and an pipe. The points of the feasibility study for the RM storage facility were summarized as follows. 1) The thermal analysis of the storage facility was done by regarding RM as a granule material and basically consisting of uranium oxide. Temperature at the center of the RM was evaluated with various thermal conductivity models in relation to RM filling ratio. 2) Temperature of the RM storage facility was also evaluated preliminarily with thermal properties of simulated oxide RM. Temperature at the center of a canister slightly exceeded a limit value of 1000degC for the RM produced in an air atmosphere. But it can be de reduced within the limit for the RM produced in a helium atmosphere. 3) Critical safety was also investigated for RM storage and it was found that sub-criticality could be achieved even in the hypothetical

  11. VVER-1000 at KNPP - nuclear fuel cycle

    Information about the realized fuel cycles in the Kozloduy NPP units 5 and 6 is presented - fuel assemblies, fuel maps, transition from 2 years fuel cycle to 3 years fuel cycle, main characteristics of the fueling, combustion depth. Some possibilities for improvements of the campaigns and usage of fuels are discussed

  12. Waveform control of fuel-cell inverter systems

    Zhu, GR; Wang, KW; Tse, CK; Tan, SC

    2012-01-01

    Fuel-cell power systems comprising single-phase DC/AC inverters draw low-frequency AC ripple currents at twice the output frequency from the fuel cell. Such a 100/120 Hz ripple current may create instability in the fuel cell system, lowers its efficiency, and shortens the lifetime of fuel cell stack. This paper1 presents a waveform control method that can mitigate such a low-frequency ripple current from being drawn from the fuel cell while the fuel-cell system delivers AC power to the load t...

  13. AC/RF Superconductivity

    Ciovati, Gianluigi [JLAB

    2015-02-01

    This contribution provides a brief introduction to AC/RF superconductivity, with an emphasis on application to accelerators. The topics covered include the surface impedance of normal conductors and superconductors, the residual resistance, the field dependence of the surface resistance, and the superheating field.

  14. AC/RF Superconductivity

    Ciovati, G.

    2015-01-01

    This contribution provides a brief introduction to AC/RF superconductivity, with an emphasis on application to accelerators. The topics covered include the surface impedance of normal conductors and superconductors, the residual resistance, the field dependence of the surface resistance, and the superheating field.

  15. Star-Forming Brightest Cluster Galaxies at 0.25 < z < 1.25: A Transitioning Fuel Supply

    McDonald, M; Bayliss, M; Allen, S W; Applegate, D E; Ashby, M L N; Bautz, M; Benson, B A; Bleem, L E; Brodwin, M; Carlstrom, J E; Chiu, I; Desai, S; Gonzalez, A H; Hlavacek-Larrondo, J; Holzapfel, W L; Marrone, D P; Miller, E D; Reichardt, C L; Saliwanchik, B R; Saro, A; Schrabback, T; Stanford, S A; Stark, A A; Vieira, J D; Zenteno, A

    2015-01-01

    We present a multi-wavelength study of 90 brightest cluster galaxies (BCGs) in a sample of galaxy clusters selected via the Sunyaev Zel'dovich effect by the South Pole Telescope, utilizing data from various ground- and space-based facilities. We infer the star formation rate (SFR) for the BCG in each cluster, based on the UV and IR continuum luminosity, as well as the [O II] emission line luminosity in cases where spectroscopy is available, finding 7 systems with SFR > 100 Msun/yr. We find that the BCG SFR exceeds 10 Msun/yr in 31 of 90 (34%) cases at 0.25 1, this fraction increases to 92(+6)(-31)%, implying a steady decrease in the BCG SFR over the past ~9 Gyr. At low-z, we find that the specific star formation rate in BCGs is declining more slowly with time than for field or cluster galaxies, most likely due to the replenishing fuel from the cooling ICM in relaxed, cool core clusters. At z > 0.6, the correlation between cluster central entropy and BCG star formation - which is well established at z ~ 0 - i...

  16. Fuel cycle: the transition between the third and the fourth generation of reactors; Cycle du combustible: faire la transition vers les 3eme et 4eme generations de reacteurs

    NONE

    2008-07-01

    Many challenges arrive today for the french research and development on the fuel cycle: promote the industrial technologies, improve the world increase of the nuclear and adapt the fuel cycle technologies to the future reactors. In this framework the report presents after a recall on the fuel cycle, the researches on the fuel, the optimization of the recycling, the wastes management, the simulation and Phenix an experimentation tool for the fuel. (A.L.B.)

  17. Dynamics and ferroelectric phase transition of (C{sub 3}N{sub 2}H{sub 5}){sub 5}Bi{sub 2}Br{sub 11} by means of ac calorimetry and {sup 1}H NMR relaxometry

    Przeslawski, J. [Institute of Experimental Physics, University of Wroclaw, 9 Max Born Square, 50-204 Wroclaw (Poland); Medycki, W. [Institute of Molecular Physics, PAS, M. Smoluchowskiego 17, 60-179 Poznan (Poland); Piecha, A. [Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw (Poland); Jakubas, R., E-mail: ryszard.jakubas@chem.uni.wroc.pl [Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw (Poland); Kruk, D. [Faculty of Mathematics and Computer Science, University of Warmia and Mazury in Olsztyn, 10-710 Olsztyn (Poland)

    2013-01-02

    Highlights: Black-Right-Pointing-Pointer The excess entropy clearly confirms an 'order-disorder' mechanism assigned to the dynamics of the imidazolium cations. Black-Right-Pointing-Pointer {sup 1}H NMR conformed dynamical heterogeneity of the imidazolium cations in low temperature phases. Black-Right-Pointing-Pointer The paraelectric-ferroelectric transition at 155 K is close to the tricritical one. -- Abstract: A quite uncommon type of heat anomaly has been disclosed by calorimetric experiments in ferroelectric crystal (C{sub 3}N{sub 2}H{sub 5}){sub 5}Bi{sub 2}Br{sub 11} close to the paraelectric-ferroelectric transition. Thermal parameters (such as the excess enthalpy ({Delta}H) and the excess entropy ({Delta}S)) of the continuous ferroelectric phase transition at ca. 155 K have been estimated and discussed. The entropy transition accompanying the ferroelectric phase transition (PT) of the order of 35 J/mol K confirms an 'order-disorder' mechanism. The ferroelectric-paraelectric PT has been described by the Landau model using the specific heat data.{sup 1}H spin-lattice relaxation at 25 MHz has been measured for this crystal in a very broad temperature range 90-420 K, covering two phase transitions (at 155 and 355 K). The relaxation data have been interpreted in terms of different dynamical properties of imidazolium cations put in structurally different environments.

  18. Increased Ac excision (iae): Arabidopsis thaliana mutations affecting Ac transposition

    The maize transposable element Ac is highly active in the heterologous hosts tobacco and tomato, but shows very much reduced levels of activity in Arabidopsis. A mutagenesis experiment was undertaken with the aim of identifying Arabidopsis host factors responsible for the observed low levels of Ac activity. Seed from a line carrying a single copy of the Ac element inserted into the streptomycin phosphotransferase (SPT) reporter fusion, and which displayed typically low levels of Ac activity, were mutagenized using gamma rays. Nineteen mutants displaying high levels of somatic Ac activity, as judged by their highly variegated phenotypes, were isolated after screening the M2 generation on streptomycin-containing medium. The mutations fall into two complementation groups, iae1 and iae2, are unlinked to the SPT::Ac locus and segregate in a Mendelian fashion. The iae1 mutation is recessive and the iae2 mutation is semi-dominant. The iae1 and iae2 mutants show 550- and 70-fold increases, respectively, in the average number of Ac excision sectors per cotyledon. The IAE1 locus maps to chromosome 2, whereas the SPT::Ac reporter maps to chromosome 3. A molecular study of Ac activity in the iae1 mutant confirmed the very high levels of Ac excision predicted using the phenotypic assay, but revealed only low levels of Ac re-insertion. Analyses of germinal transposition in the iae1 mutant demonstrated an average germinal excision frequency of 3% and a frequency of independent Ac re-insertions following germinal excision of 22%. The iae mutants represents a possible means of improving the efficiency of Ac/Ds transposon tagging systems in Arabidopsis, and will enable the dissection of host involvement in Ac transposition and the mechanisms employed for controlling transposable element activity

  19. Hermetisk AC-Krets

    Hirsch, Carl; Smirnoff, Alexander

    2007-01-01

    Under sex månader våren 2007 har ett samarbete mellan Volvo Lastvagnar och två studenter från KTH, inriktning Integrerad produktutveckling vid institutionen för maskinkonstruktion, pågått i form av ett examensarbete på 20 poäng. Dagens AC-system i Volvos lastbilar avger 20-40 g/år av köldmediet R134a som är en kraftfull växthusgas. Detta sker främst genom diffusion via slangar och tätningsmaterial. Syftet med detta examensarbete är att ta fram förslag på tekniska lösningar på ett nytt AC-syst...

  20. AC susceptibility of polycrystalline (Bi-Pb 2223 superconductors

    H. Salamati

    2004-06-01

    Full Text Available   The temperature dependence of ac susceptibility of (Bi-Pb2223 polycrystalline samples was measured as a function of frequency and ac field amplitude. Analysis of the temperature dependence of the AC susceptibility near the transition temperature (Tc has been done employing Bean’s critical state model. The observed variation of intergranular critical current densities (Jc with temperature indicates that the weak links are superconductor- normal metal-superconductor (SNS type for this sample. The frequency effect on AC susceptibility was also measured. As the frequency increases, (TP shifts to higher temperatures. This effect can be interpreted in terms of flux creep. The temperature T, and field, , dependence of activation energy obtained from the Arrhenius plot for the frequency ( f and ( TP , can be described as: U(Hac,T=U0(1-T/TCHac-0.18

  1. Energy saving measures for automotive air conditioning (AC) system in the tropics

    Subiantoro, Alison; Ooi, Kim Tiow; Stimming, Ulrich

    2014-01-01

    Air conditioning (AC) is an integral component of modern cars in the tropics. However, AC usage in this region consumes a large amount of energy. In conventional internal combustion engine cars, it consumes up to 30% of the fuel, while in battery electric cars, AC may reduce the battery range by up to 40%. Fortunately, there are various ways to improve the efficiency of automotive ACs in the tropics. In this paper, three energy saving measures are discussed. These include a higher indoor temp...

  2. High performance AC drives

    Ahmad, Mukhtar

    2010-01-01

    This book presents a comprehensive view of high performance ac drives. It may be considered as both a text book for graduate students and as an up-to-date monograph. It may also be used by R & D professionals involved in the improvement of performance of drives in the industries. The book will also be beneficial to the researchers pursuing work on multiphase drives as well as sensorless and direct torque control of electric drives since up-to date references in these topics are provided. It will also provide few examples of modeling, analysis and control of electric drives using MATLAB/SIMULIN

  3. Superconducting ac cable

    The components of a superconducting 110 kV ac cable for power ratings >= 2000 MVA have been developed. The cable design especially considered was of the semiflexible type, with a rigid cryogenic envelope and flexible hollow coaxial cable cores pulled into the former. The cable core consists of spirally wound Nb-Al composite wires and a HDPE-tape wrapped electrical insulation. A 35 m long single phase test cable with full load terminations for 110 kV and 10 kA was constructed and successfully tested. The results obtained prove the technical feasibility and capability of our cable design. (orig.)

  4. Ac Hybrid Charge Controller

    Shalini S. Durgam

    2015-03-01

    Full Text Available One of the primary needs for socio-economic development in any nation in the world is the provision of reliable electricity supply systems with lower carbon footprint levels. The purpose of this work is the development of a hybrid Power system that harnesses the renewable energy in sun and electricity to generate electricity. The working model can able to run on dual mode- solar and electricity. It can also be driven independently either by solar or electricity. The battery can be charge from solar panel (40W or by power supply. The household single phase A.C. power supply of 230V is converted into 12V D.C. using step down transformer and rectifying circuit. The working model can achieve energy saving, low carbon emission, environmental protection for the upcoming future of human life.

  5. AcEST: BP920072 [AcEST

    Full Text Available YMU001_000132_F11 525 Adiantum capillus-veneris mRNA. clone: YMU001_000132_F11. BP920072 - Show ... YGMYGEGEKALETFADMEKSGIVPDSVVFIAII 617 Query: 139 NACSR SCLFHECHSYFEAMSTHHGIVPCLEHHSCVV 32 ACS S L E + FE M ... KLMTRDVVSWNTLIAGYAQVGQNEGLFCTFSDMLGQRVKPDLITFVIVLNACSR ... 125 VF+ + +D VSWN++I+GY Q G F M+ + D IT++++++ +R S ... YGVHGYGKKAIQIFEEMLANGASP 384 Query: 166 DLITFVIVLNACSR SCLFHECHSYFEAMSTHHGIVPCLEHHSCVV 32 +TFV VL ACS L E ... KLMTRDVVSWNTLIAGYAQVGQNEGLFCTFSDMLGQRVKPDLITFVIVLNACSR S 122 +VFDK R + WN L G E + + M V+ D T+ VL AC S Sbjc ...

  6. Induction Motor Control through AC/DC/AC Converters

    Elfadili, Abderrahim; Giri, Fouad; Ouadi, Hamid; El Magri, Abdelmounime; Dugard, Luc; Abouloifa, Abdelmajid

    2010-01-01

    We consider the problem of controlling inductions motors driven through AC/DC rectifiers and DC/AC inverters. The control objectives are threefold: (i) forcing the motor speed to track a reference signal, (ii) regulating the DC Link voltage, (iii) assuring a satisfactory power factor correction (PFC) with respect to the power supply net. First, a nonlinear model of the whole controlled system is developed in the Park-coordinates. Then, a nonlinear multi-loop controller is synthesized using th...

  7. AcEST: BP920905 [AcEST

    Full Text Available EM + + D ++S L AC Sbjct: 374 NSAYKLFERMPKKNVVAWNAIISGYSQHGHPHEALALFIEMQAQGIKPDSFAIVSVLPAC 433 Query: 71 SHSSTLNDGKLIHFYILMNNFE...EM++ ++ + V + S L +C Sbjct: 255 SSERIFEKIAKKNAVSWTAMISSYNRGEFSEKALRSFSEMIKSGIEPNLVTLYSVLSSCG 314 Query: 68 HSSTLNDGKLIHFYILMNNFE...VVVMSCLKACS 69 ++ +F RRD VTW A+I GYA HG E A+ LF+ M+ EN+ + V +S L+AC+ Sbjct: 656 DSRLMFEKSLRRDFVTWNAMICGYAHHGKGEEAIQLFERMILEN...ELEKMHNKRLQEMCVSWNSIISGYVMKEQSEDAQMLFTRMME 596 Query: 122 ENVDTDGVVVMSCLKACSHSSTLNDGKLIHFYILMNNFE ...FCEADT-NVITWNAMIASYVHCEQSEKAIALFDRMVSENFKPSSITLVTLLMAC 543 Query: 71 SHSSTLNDGKLIHFYILMNNFEL 3 ++ +L G++

  8. AcEST: DK950147 [AcEST

    Full Text Available TST38A01NGRL0007_O05 706 Adiantum capillus-veneris mRNA. clone: TST38A01NGRL0007_O05. 5' end seq ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... OS=Medicago truncatula GN=MtrDRAFT_AC149576g3v2 PE ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... (Fragment) OS=Medicago truncatula GN=MtrDRAFT_AC14 ...

  9. AcEST: DK959344 [AcEST

    Full Text Available TST39A01NGRL0004_G23 714 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0004_G23. 5' end seq ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... OS=Medicago truncatula GN=MtrDRAFT_AC149576g3v2 PE ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... (Fragment) OS=Medicago truncatula GN=MtrDRAFT_AC14 ...

  10. AcEST: DK949716 [AcEST

    Full Text Available TST38A01NGRL0006_L20 613 Adiantum capillus-veneris mRNA. clone: TST38A01NGRL0006_L20. 5' end seq ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... OS=Medicago truncatula GN=MtrDRAFT_AC149576g3v2 PE ... _MEDTR Peptidase, trypsin-like serine and cysteine proteases ... (Fragment) OS=Medicago truncatula GN=MtrDRAFT_AC14 ...

  11. AC Motor Drive Fed by Renewable Energy Sources with PWM

    J. Pavalam

    2014-01-01

    Full Text Available In this fast aproaching nature of technology the ned of Electricity becomes a mandatory in developing technology. The ned of Electricity increases the power demand where the power demand met by the conventional sources of energy has some disadvantage of polution, this disadvantage can be decreased by the use of the Renewable energy sources like Fuel Cel and available solar energy. When a FUEL cel produces AC power, basicaly two stages are required for conversion first a bosting stage and second is inversion stage. In this paper the Bost inverter topology is achieved where in the conventional methods the normal DC - AC power conversion method is used where as in this paper the PWM based DC - AC inverter has ben used which is useful in reducing the harmonics in the output of the Inverter. The voltage controled output is produced in the bost inverter the curent controled output is taken from dc-dc bidirectional converter. The Fuel cel canot be relied as a whole so a Solar PV module is conected acros the Load so while the Sunlight days the PV arays generate power and in the night time the Fuel cel is used to generate power for the load. Since, the Fuel cel and PV arays can generate power in Partial load they are prefered than any other sources. When the output from the Solar PV aray is low or when the sunlight available is not eficient in generating the power a automatic switch over is provided in the junction betwen the Solar PV aray and Fuel cel so that whenever it hapens the switch automaticaly switch over to another source. The simulation results are presented to confirm the operational feature of the proposed system.

  12. AC drives for industrial plants. Plant kudoyo AC drive sochi

    Miyazaki, M.; Shibata, M.; Yamada, S. (Toshiba Corp., Tokyo (Japan))

    1992-08-01

    Features and product series of AC drives for industrial plants were outlined. Configurations and features of various types of AC drives were briefly discussed which are put into market to meet various requirements for industrial plants and wide ranges of output voltage and capacity. The following product series were outlined; the power bipolar transistor inverter for 3.5-600 kVA in output capacity, IGBT inverter for AC 400 V in output voltage and 1,000 kVA or less, GTO inverter for AC 600 V and 700-2,000 kVA, and cycloconverter for AC 1,000-3,000 V and 1,000 kW-20 MW. The following subjects were outlined as current technical trends of AC drives for industrial plants; increasing in capacity of voltage-source PWM inverters, downsizing of converters through highly efficient cooling and highly dense mounting, spreading of sensorless vector controls, and development of high-voltage large-capacity PWM inverters. 6 figs., 2 tabs.

  13. Djungle power. A more remote AC bus

    Boehnke, Heinz W. [Technosol, Jork (Germany)

    2010-07-01

    The Dzanga-Sangha Reserve in the Central African Republic is probably one of the world's most remote protected rainforest areas, much to the benefit of the rare species of lowland gorilla, forest elephant and local pygmy population Ba'Aka. The park is co-managed by the ''WWF-World Wide Fund for Nature'' with sponsoring from the German Regenwald-Stiftung. In 2008 wwf decided to switch from the old, failing generator supply to a solar hybrid mini-grid, along with stringent measures of energy conservation and management. After a careful energy audit Technosol designed an AC-bus system with a 22 kWp PV generator which should overcome the dependency on the old generators and their fuel demands. For 15 buildings, an entirely new distribution network was installed, state of the art energy saving devices introduced and an energy metering system deviced. The installation is operating since August 2009. In such remote locations, the reliability of the AC-bus over other generator-based solutions will be demonstrated and with the support of international organisations like the wwf the practical application of solar hybrid supply becomes a landmark of sustainable energy concepts. (orig.)

  14. Operation and Control of Grid Connected Hybrid AC/DC Microgrid using various RES

    Kodanda Ram R B P U S B

    2014-10-01

    Full Text Available This paper proposes a Hybrid AC/DC Microgrid in alliance with Photo Voltaic (PV energy, Wind Energy and Proton Exchange Membrane (PEM Fuel cells. Microgrids are becoming increasingly attractive to the researchers because of the less greenhouse gases, low running cost, and flexibility to operate in connection with utility grid. The Hybrid AC/DC Microgrid constitutes independent AC and DC subgrids, where all the corresponding sources and loads are connected to their respective buses and these buses are interfaced using an interfacing converter. The Hybrid AC/DC Microgrid increases system efficiency by reducing the multiple reverse conversions involved in conventional RES integration to grid. A Small Hybrid AC/DC Microgrid in grid connected mode was modeled and simulated in MATLAB-SIMULINK environment. The simulation results proves the stable operation considering the uncertainty of generations and loads.

  15. Turning Atucha-1 PHWR from natural to slightly enriched uranium fuel operation: reassessing power limits for the first phase of transition

    Main features of Atucha-1 PHWR design and actual operation, using natural Uranium fuel, are outlined. The low exit burnup of this fuel, with its impact on the electricity generating cost, led to the implementation of a major change in the operation of this rather aged NPP, namely, the use of slightly enriched Uranium fuel. The original safety limits established for natural Uranium operation were focused on limits to power values for the central core region, with less well defined limits for the rest of the core, where the new fuel assemblies will soon be loaded. Recently, a number of assumptions were adopted and thermal-hydraulic calculations with Cobra-4 code were carried out in order to established consistent power limits for all of the core's radial hydraulic zones under different operating conditions. Finally, other margins were included in order to link the thermal-hydraulic limits to the final power limits to be applied in neutronic calculations, either for operation follow-up or in-core fuel management. (author)

  16. AcEST: DK955197 [AcEST

    Full Text Available TST39A01NGRL0022_H07 532 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0022_H07. 5' end seq ... KDEVTALPLLK 192 Query: 194 RFAFGIACELLMSRYEKEEQEMLEEPF TTMMKGILQLPIKLPGTRFSKAIVAANMLRARF 373 R+ F +AC+L S ... KDEVMALPLLK 192 Query: 194 RFAFGIACELLMSRYEKEEQEMLEEPF TTMMKGILQLPIKLPGTRFSKAIVAANMLRARF 373 R+ F +AC+L S ... KDEVKVLP 189 Query: 185 LMKRFAFGIACELLMSRYEKEEQEMLEEPF TTMMKGILQLPIKLPGTRFSKAIVAANMLR 364 L++ F IA L + +Q+ ... KDEATVLP 177 Query: 185 LMKRFAFGIACELLMSRYEKEEQEMLEEPF TTMMKGILQLPIKLPGTRFSKAIVAANMLR 364 L+K F +A L E+ QE ...

  17. AcEST: BP915640 [AcEST

    Full Text Available YMU001_000074_A01 462 Adiantum capillus-veneris mRNA. clone: YMU001_000074_A01. BP915640 CL3685C ... y: 462 GPLILRACLVYMQGAPVGSLAEDGIVSAATGKDMEQSTVGFRLMLAKI IHRLIAAFKEVG 283 G IL+AC YM+G +GSL +D V ++VGF+LMLAK ... : 1032 GYYILKACDAYMKGYLIGSLTKDASVIDERSS-ANSTSVGFKLMLAKI APKLFSALSEVG 1090 Query: 282 AYCDAYE 262 A C+ ++ Sb ... uery: 453 ILRACLVYMQGAPVGSLAEDGIVSAATGKDMEQSTVGFRLMLAKI IHRLIAAFKEVGAYC 274 +L AC YM+G PVGS A G ST GF++ML+K ... ame = -1 Query: 423 GAPVGSLAEDGIVSAATGKDMEQSTVGFRLMLAKI I----HRLIAAFKEVGAYCD 271 G P+ L D +S GK + S RL + L+ ...

  18. Speed Control of DC Motor using AC/AC/DC Converter Based on Intelligent Techniques

    Rakan Kh Antar

    2013-05-01

    Full Text Available    This paper describes the application of ac/ac/dc and ac/dc converters to control the speed of a separately excited DC motor. Artificial neural network and PI controller are trained to select the desired values of firing angles for triggering thyristors of the ac/ac/dc and ac/dc bridge converters in order to control the speed of the dc motor at a desired value with constant and different load torques in order to obtain the best speed response. Simulation results show that the rising time for ac/dc and ac/ac/dc converters at 250rpm are reduced about 79% and 89% respectively, while delay time it reduced about 69% and 64% respectively. Therefore, speed response of the dc motor is more efficient for closed loop system compared with open loop also the response of ac/ac/dc converter is better than ac/dc converter.

  19. Cracked fuel mechanics

    Fuel pellets undergo thermally induced cracking during normal reactor operation. Some fuel performance codes have included models that address the effects of fuel cracking on fuel rod thermal and mechanical behavior. However, models that rely too heavily on continuum mechanics formulations (annular gaps and solid cylindrical pellets) characteristically do not adequately predict cladding axial elongations. Calculations of bamboo ridging generally require many assumptions concerning fuel geometry, and some of the methods used are too complex and expensive to employ on a routine basis. Some of these difficulties originate from a lack of definition of suitable parameters which describe the cracked fuel medium. The methodology is being improved by models that describe cracked fuel behavior utilizing parameters with stronger physical foundations instead of classical continuum formulations. This paper presents a modelling concept and a set of measurable parameters that have been shown to improve the prediction of the mechanical behavior of cracked fuel/cladding systems without added computational expense. The transition from classical annular gap/cylindrical pellet models to modified bulk properties and further to local behavior for cracked fuel systems is discussed. The results of laboratory experiments to verify these modelling parameters are shown. Data are also presented from laboratory experiments on unirradiated and irradiated rods which show that fuel rod mechanical response depends on fuel fragment size. The impact of these data on cracked fuel behavior and failure modelling is also discussed. (author)

  20. AcEST: BP920800 [AcEST

    Full Text Available DLNLALQVHSRMVRFGFNAEVEACGALINMYGKCGKVLYAQRVFDDT 298 Query: 206 RQQDVISWNDIISACAQRGHGTEALENFSQMLHEGIVPNSMTFTSVMQA---CNSIEGG...G L +A S F ++ +D+ISW +I +Q EA+ F Sbjct: 217 SEKNEATSNCLINGYMGLGNLEQAESLFNQMPVKDIISWTTMIKGYSQNKRYREAIAVFY 276 Query: 119 QMLHEG...EKAWRIFDGVSCKNLPSWNAIITGCVQGGLLEEAIDLYRHMK 281 Query: 110 HEGIVPNSMTFTSVMQAC---NSIEGGR 36 + + PN +T +V+ AC +...N IIS AQ G +EA+E ++ M Sbjct: 383 DITIGNAVVVMYAKLGLVDSARAVFNWLPNTDVISWNTIISGYAQNGFASEAIEMYNIME 442 Query: 110 HEG...EIDLGEQIHSLSVKTGFESDMYVSGVLIDMYSKYGWLEKARRVLEML 406 Query: 206 RQQDVISWNDIISACAQRGHGTEALENFSQMLHEGIVPNSMTFTSVMQACNSIEGG

  1. AcEST: DK945549 [AcEST

    Full Text Available AGGCGATTTCATCTTTTCTGAGAACCCTGATTTTGTGATTGTGTAATTACA ACTGTGGAACAGAAGGATGAGAAGTCTACTGACACAACAAGATATCTCTGGAGAGGAGA...A AATTGAGAAGGTTTGAGTTCTCAACAATGGGCTATGAGGCAATAATGGGAAGGCACCGAT TGTGGGCTTGTATAGGTTTTGAC...LCTG 239 L++R+LRR + + ++ G AC+ DP +P PLC+G Sbjct: 108 LQQRELRRKLLADSGALNTNSVNGPRNWKACVQQDPSSRPGTPLCSG 154 >sp|A6UUY8|RNZ_META3...49 Tissue type young leaves Developmental stage sporophyte Contig ID CL454Contig1 Sequence GATGAGCGA...CCACCTGTGCAACCGTCAGCGCCTTTGTGCACTGGTG CAATGTCCTGTGGTTACCTTGTTTGGAATCTTAATTGTTCTCATGTAT

  2. AcEST: BP917632 [AcEST

    Full Text Available YMU001_000103_D10 554 Adiantum capillus-veneris mRNA. clone: YMU001_000103_D10. BP917632 - Show ... YSKCKIHQKALELLVLML 154 Query: 466 KDSLEPDEVTYLNVLKACARE EDLKV 543 +D++ P+ TY +VL++C D+++ Sbjct: 155 RDNVRPN ... 185 Query: 415 GHSDSS--KEALKLLTQMRKDSLEPDEVTYLNVLKACARE EDLK 540 + EA KL +M+ ++ PDE+ N++ AC R +++ Sbjct: 18 ...

  3. AcEST: DK961189 [AcEST

    Full Text Available OS=A... 127 7e-29 sp|Q94B08|GCP1_ARATH Germination-specific cysteine protease 1 OS... 125 2e-28 sp|P00785|AC...IRNSWGLNWGDSGYVKLQRNIDDPFGKCGIAMMPSYP 347 >sp|Q94B08|GCP1_ARATH Germination-specific cysteine protease 1 OS=

  4. AcEST: DK946687 [AcEST

    Full Text Available YMU02A01NGRL0013_G11 544 Adiantum capillus-veneris mRNA. clone: YMU02A01NGRL0013_G11. 5' end seq ... + G P+ TY+ + AC+ E Sbjct: 97 YSFNYMIRGLTNTWN-------DHEA ---ALSLYRRMKFSGLKPDKFTYNFVFIACAKLE 146 Query: 214 A ... Sbjct: 71 LIPKAVELGDFNYSSFLFSVTEEPNHYSFNYMIRGLTNTWNDHEA ALSLYRRMKFSGLKP 130 Query: 469 DGATFSCVLRACGNVGALDV ...

  5. AcEST: DK949372 [AcEST

    Full Text Available TST38A01NGRL0005_N02 627 Adiantum capillus-veneris mRNA. clone: TST38A01NGRL0005_N02. 5' end seq ... 363 DQLREKTC-GVDKFDDIVMACXXXXXXXXXXXXXXXXXXKARVHAYGVCD DPEYFYDYVQ 539 Q++EK G+ FDDIV+AC KA+VHA+ VCD DP+YFYD ... 264 QQVQEKKVPGITFFDDIVVACGSGGSIAGLSLGSYLSNLKAKVHAFAVCD DPDYFYDYTQ 323 Query: 540 GLLDGMNANIASRDIVNVIDAKGLG ...

  6. Effects of AC Electric Field on Small Laminar Nonpremixed Flames

    Xiong, Yuan

    2015-04-01

    Electric field can be a viable method in controlling various combustion properties. Comparing to traditional actuators, an application of electric field requires very small power consumption. Especially, alternating current (AC) has received attention recently, since it could modulate flames appreciably even for the cases when direct current (DC) has minimal effects. In this study, the effect of AC electric fields on small coflow diffusion flames is focused with applications of various laser diagnostic techniques. Flow characteristics of baseline diffusion flames, which corresponds to stationary small coflow diffusion flames when electric field is not applied, were firstly investigated with a particular focus on the flow field in near-nozzle region with the buoyancy force exerted on fuels due to density differences among fuel, ambient air, and burnt gas. The result showed that the buoyancy force exerted on the fuel as well as on burnt gas significantly distorted the near-nozzle flow-fields. In the fuels with densities heavier than air, recirculation zones were formed very close to the nozzle exit. Nozzle heating effect influenced this near-nozzle flow-field particularly among lighter fuels. Numerical simulations were also conducted and the results showed that a fuel inlet boundary condition with a fully developed velocity profile for cases with long fuel tubes should be specified inside the fuel tube to obtain satisfactory agreement in both the flow and temperature fields with those from experiment. With sub-critical AC applied to the baseline flames, particle image velocimetry (PIV), light scattering, laser-induced incandescence (LII), and laser-induced fluores- cence (LIF) techniques were adopted to identify the flow field and the structures of OH, polycyclic aromatic hydrocarbons (PAHs), soot zone. Under certain AC condi- tions of applied voltage and frequency, the distribution of PAHs and the flow field near the nozzle exit were drastically altered from the

  7. Fuel cycle. Fuel reprocessing

    Reprocessing includes mechanical and chemical operations on spent fuel for extraction of valuable materials. These operations are a part of the fuel cycle. In this paper are given technical data on spent fuels, transport, storage, decladding, dissolution, Purex process, elaboration of U and Pu and reprocessing engineering. This article is completed by 106 references

  8. Analysis of Russian transition scenarios to innovative nuclear energy system based on thermal and fast reactors with closed nuclear fuel cycle using INPRO methodology

    This paper presents the results of the analysis of modeling of Russian nuclear energy (NE) scenarios on the basis of thermal and fast reactors with closed nuclear fuel cycle (NFC). Modeling has been carried out with use of CYCLE code (SSC RF IPPE's tool) designed for analysis of Nuclear Energy System (NES) with closed NFC taking into account plutonium and minor actinides (MA) isotopic composition change during multi-recycling of fuel in fast reactors. When considering fast reactor introduction scenarios, one of important questions is to define optimal time for their introduction and related NFC's facilities. Analysis of the results obtained has been fulfilled using the key INPRO indicators for sustainable energy development. It was shown that a delay in fast reactor introduction led to serious ecological, social and finally economic risks for providing energy security and sustainable development of Russia in long-term prospects and loss of knowledge and experience in mastering innovative technologies of fast reactors and related nuclear fuel cycle. (author)

  9. Energy saving in ac generators

    Nola, F. J.

    1980-01-01

    Circuit cuts no-load losses, without sacrificing full-load power. Phase-contro circuit includes gate-controlled semiconductor switch that cuts off applied voltage for most of ac cycle if generator idling. Switch "on" time increases when generator is in operation.

  10. Apuntes de Acústica

    Martín Domingo, Agustín

    2014-01-01

    Esta publicacion contiene unos apuntes para la parte de Acústica de las asignaturas de la ETSAM, junto con cierta cantidad de material adicional que excede el ámbito del curso. Aunque está lejos de ser completa y de estar libre de errores, el autor espera sea útil.

  11. SSTI Clark ACS Technology Demonstrations

    Freesland, Douglas

    1997-01-01

    SSTI Clark, one of two spacecraft built under NASA's Small Satellite Technology Initiative, includes seven ACS technology demonstrations. The technologies redefine the performance cost envelope, providing improved sensor and actuator performance at reduced costs. Six sensing technologies are being flown consisting of both hardware and algorithmic demonstrations: autonomous star tracker, hemispherical resonating gyro, GPS attitude determination, miniature horizon sensors, low cost course sun s...

  12. Validation of ion chromatography for the determination of transition metal ions along with alkali, alkaline earth metal elements for uranium oxide fuel

    The present report describes the use of Ion chromatography (IC) methods with spectrophotometric and direct conductivity detection for the determination of transition metal elements and alkali alkaline earth metal ions in UO2 pellets. Transmet analytical column and Metrosep- cation 1-2 column were used for the separation of transition metal elements and alkali and alkaline earth metal elements respectively. Oxalic acid and mixture of pyridine 2,6-dicarboxylic acid (PDCA), Na2SO4 and NaCl were used as mobile phase for the separation of transition metal ions and monitored after post - column reaction with 4,2-pyridylazo resorcinol (PAR) at 520nm spectrophotometrically. In the determination of alkali and alkaline earth metal ions the interference of transition metals are removed by complexing them with PDCA. Mixture of tartaric acid and PDCA employed in the separation of alkali and alkaline earth metal ions and monitored on direct conductivity detector. Mobile phase composition was optimised for the base line separation. Calibration plots of Fe3+, Cu2+, Ni2+, Co2+, Cd2+, Mn2+, Li+, Na+, K+, Mg2+, Ca2+ and Sr2+ were linear over a wide dynamic range with regression coefficient better than 0.999. Detection limit of above ions were between 5-30ppb. To prevent the overloading of the cation exchange column, uranium matrix was removed from UO2 sample by solvent extraction with 30% TBP - TOPO/CCl4. Ten sintered UO2 pellets of same lot were analysed and R.S.D. ±10% was obtained. These methods were validated by analysis of ILCE standards of UO2. (author)

  13. AcEST: DK950895 [AcEST

    Full Text Available |A7SFA3|A7SFA3_NEMVE Predicted protein OS=Nematostella vectens... 210 5e-53 tr|Q0CVA9|Q0CVA9_ASPTN ATP-citrate synthase subunit...stX Result : Swiss-Prot sp_hit_id Q54YA0 Definition sp|Q54YA0|ACLY_DICDI Probable ATP-citrate synthase OS=Dictyos...PIDYSWAQELGLIRKPAAFISTI 404 >sp|Q8X097|ACL1_NEUCR Probable ATP-citrate synthase subunit 1 OS=Neurospora cras...IRKPASFMTSI 844 >sp|Q9P7W3|ACL1_SCHPO Probable ATP-citrate synthase subunit 1 OS=Schizosaccharomyces pombe G....done Score E Sequences producing significant alignments: (bits) Value sp|Q54YA0|ACLY_DICDI Probable ATP-citrate synthase OS=Dictyos

  14. AcEST: BP914304 [AcEST

    Full Text Available IDEHTFVFTLRAC 4 V+ NA++ Y G+ E A++ + +M+ E++ + TF+ LRAC Sbjct: 670 VTWNAMICGYAHHGKGEEAIQLFERMILENIKPNHVTFISI...KSLRRDFVTWNAMICGYAHHGKGEEAIQLFERMILENIKPN 703 Query: 339 NLTYVSLFKACGNVLDFGQG-RTIHGEARANGFSSDRFICTTLI...TFVFTLRAC 4 +F + + V+ N ++ +YV A +++M + D TL+AC Sbjct: 484 QIFERMCDRDNVTWNTIIGSYVQDENESEAFDLFKRMNLCGIVSDGACL...K + A+Q+ + R + +W++MI++ +A + ++ M Sbjct: 93 LGNSLINFYSKFEDVASAEQVFRRMTLRDVVTWSSMIAAYAGNNHPAKAFDTFERMTDAN 152... + R + +W++MI++ +A + ++ M Sbjct: 93 LGNSLINFYSKFEDVASAEQVFRRMTLRDVVTWSSMIAAYAGNNHPAKAFDTFERM

  15. AcEST: BP911793 [AcEST

    Full Text Available + +VSWN +++ Y QHG + ++L+ M+AE T N + + A Sbjct: 58 EAKFVFERIQNKDVVSWNCIINGYSQHGPSGSSHVMELFQRMRAENTAPNAHTFAGVF... N + + A Sbjct: 58 EAKFVFERIQNKDVVSWNCIINGYSQHGPSGSSHVMELFQRMRAENTAPNAHTFAGVFTA 117 Query: 359 CIQTGNLELCKQM...D VT S+LSACSH G + +G YF Sbjct: 602 IIGGSAQHGRGQDALQLFERMKMEGVKPDIVTFVSLLSACSHAGLLEEGRRYF 654 Score = 115 bit...53 QTGNLELCKQMHFNIVSAGNELNPSLASSLIRTYGNCGSMLDAHAVFDSLPLPDIVSWNV 174 Q +E+ K++ F+++ N S +++I Y CG + +A +FD +P D VSW Sbjct: 324 QGERME... L+ M +E + I+LV +L AC+ TG+LE + +H Sbjct: 498 VITWNAMIASYVHCEQSEKAIALFDRMVSENFKPSSITLVTLLMACVNTGSLER

  16. AcEST: BP921649 [AcEST

    Full Text Available 40 + ++LV YAK L + ++ +P R W+ +I+ + + ++E AL+ + M+ G Sbjct: 144 VASSLVGMYAKFNLFENSLQVFDEMPERDVASWNTVISCFYQSGEAEKALELFGRME...LDCYKEM 52 ++L +GNALVD YAKCG L A ++ +R+ R V W+ +I Y + E A D +K M Sbjct: 461 KNLFVGNALVDMYAKCGALEDARQIFERMCDRDNVTWNTIIGSYVQDEN...RD+ WNA+I Sbjct: 237 LEQGKQIHCYAIRSG-IESDVLVVNGLVNMYAKCGNVNTAHKLFERMPIRDVASWNAIIG 295 Query: 411 GYVNHGRAEVALDCFGKME...SNDVV-GNALVNMYAKCGNVNSAYKLFERMPKKNVVAWNAIIS 396 Query: 411 GYVNHGRAEVALDCFGKME... HGR + AL F +M+ EG PD +TF +L AC G + + + + Sbjct: 603 IGGSAQHGRGQDALQLFERMKMEGVKPDIVTFVSLLSACSHAGLLEEGRRYFCSM

  17. AcEST: BP919669 [AcEST

    Full Text Available D + RDV SW ++S + + G+ ++F M G +P+ Sbjct: 148 LVGMYAKFNLFENSLQVFDEMPERDVASWNTVISCFYQSGEAEKALELFGRMESSGFEPN 20...+ +++AC L + +G+E+H + K+G EL V Sbjct: 190 EKALELFGRMESSGFEPNSVSLTVAISACSRLLWLERGKE...F Sbjct: 468 IY---VVNSLIDSYGKCSHVEDAERIFEECTIGDLVSFTSMITAYAQYGQGEEALKLFLE 524 Query: 226 MVGEGTKPDSISLLVVLRA-YNF...+ IR DV W +LMSGY+K D ++F ++ Sbjct: 44 SLINVYFTCKDHCSARHVFENFDIRSDVYIWNSLMSGYSKNSMFHDTLEVFKRLLNCSIC 103 Query: 208 KPDSISLLVVLRAYNF...KPD Sbjct: 261 VDMYAKCGCIETAVEVFEKLTRRNVFSWAALIGGYAAYGYAKKATTCLDRIEREDGIKPD 320 Query: 199 SISLLVVLRAYNFLGFP

  18. AcEST: DK957916 [AcEST

    Full Text Available PQKQPVPAVSHSPQKSSTPPTPAATKPKEEPSVPKEVPKLQQGKLEKT 967 Query: 577 --TTEASQGIPVEEG...G E+ P+ P Sbjct: 1974 QEQGRAPSQDQEAPSPEALPSPGQEPAAGASPRRGELRRGSSAESALPRAGP 2025 >sp|Q05175|BASP_RAT Brain ac... +P AP P Sbjct: 388 ERETAASAGPQG----AFPEPRPAQPSAGPEPRPAQPSAGPEPRPAQPSAAPEPRP---- 439 Query: 571 GQTTE... L ++ +A+ +E AP Sbjct: 406 IVTTPEPEGSGEEDVPKPDEIPEKEVTEEELIKVSTAAPAKASPEEEVVKATTLAPSEED 465 Query: 550 VSPYIASGQTTE... Query: 424 KGQAYEAIPDPHVDPAAGVHERLAQLQLGDEPEATKPKEAPG-VSPYI--ASGQTTEASQ 594 K A E P + + G E + E EA P A G +P

  19. AcEST: DK956923 [AcEST

    Full Text Available CCATAGTCTCAA CAGCGATAAGCAGGAAATGCATGCAGTGACCATGGGTAAGAAAAGGGTCATGGTGGGCGC CATTAACACGATACTTATCCTA...CTCCTCTTGCAGTTTATGAAGCAATGTTCTTCCTCTTC TAGTCATGATGATGATGGCGATGCCTTTGCGGATGACACTCTAAGCAGACGCAACGAT...AC GGTCGAGTCTGCTCCTCGACATTGGCCAAGGCGAATGCTGGGCAGCCAAGAACCTGCCTC CAACAAGACTTCATATGGTATTCCTGAT...H At1g73965 (CLE13 / CLAVATA3/ESR-Related 13) (CLE13) OS=Arabidopsis thaliana Align length 25 Sco...icant alignments: (bits) Value tr|Q6NMF0|Q6NMF0_ARATH At1g73965 (CLE13 / CLAVATA3/ESR-Related 1... 49 3e-04

  20. AcEST: BP921492 [AcEST

    Full Text Available + AL +G+ +H Sbjct: 286 DVASWNAIIGGYSLNSQHHEALAFFNRMQVRGIKPNSITMVSVLPACAHLFAL... ++ L +GK +H Sbjct: 178 NLVSWTAMVSGYAQGGFADEALRMFYEMQGEDVKANYVTVASVLPACAQLSDLQQGKEIH 237 Query: 153 AC...FDRMPEK 171 Query: 333 DVVSWSAMIAMYGQQGCGKEAFQLFQEMACEGGMPNRVTYVSILDACASVAALPEGKLVH 154 +V+W+++++ + Q G EA Q+F +M G P+ T+VS+L ACA...333 DVVSWSAMIAMYGQQGCGKEAFQLFQEMACE-GGMPNRVTYVSILDACASVAALPEGKLV 157 +V +W+AMI+ YG G G++A +LF +M + G +PN VT+V++L ACA...SKL 85 Query: 288 GCGKEAFQLFQEMACEGGMPNRVTYVSILDACASVAALPEGKLVHACFMESELELDVVVG 109 ++ M P+ T+ S++ +CA ++AL G

  1. Transition Planning

    Statfeld, Jenna L.

    2011-01-01

    Post-school transition is the movement of a child with disabilities from school to activities that occur after the completion of school. This paper provides information about: (1) post-school transition; (2) transition plan; (3) transition services; (4) transition planning; (5) vocational rehabilitation services; (6) services that are available…

  2. Electricity generation analyses in an oil-exporting country: Transition to non-fossil fuel based power units in Saudi Arabia

    In Saudi Arabia, fossil-fuel is the main source of power generation. Due to the huge economic and demographic growth, the electricity consumption in Saudi Arabia has increased and should continue to increase at a very fast rate. At the moment, more than half a million barrels of oil per day is used directly for power generation. Herein, we assess the power generation situation of the country and its future conditions through a modelling approach. For this purpose, we present the current situation by detailing the existing generation mix of electricity. Then we develop a optimization model of the power sector which aims to define the best production and investment pattern to reach the expected demand. Subsequently, we will carry out a sensitivity analysis so as to evaluate the robustness of the model's by taking into account the integration variability of the other alternative (non-fossil fuel based) resources. The results point out that the choices of investment in the power sector strongly affect the potential oil's exports of Saudi Arabia. (authors)

  3. Monitoring colloidal stability of polymer-coated magnetic nanoparticles using AC susceptibility measurements.

    Herrera, Adriana P; Barrera, Carola; Zayas, Yashira; Rinaldi, Carlos

    2010-02-15

    The application of the response of magnetic nanoparticles to oscillating magnetic fields to probe transitions in colloidal state and structure of polymer-coated nanoparticles is demonstrated. Cobalt ferrite nanoparticles with narrow size distribution were prepared and shown to respond to oscillating magnetic fields through a Brownian relaxation mechanism, which is dependent on the mechanical coupling between the particle dipoles and the surrounding matrix. These nanoparticles were coated with covalently-attached poly(N-isopropylacrylamide) (pNIPAM) or poly(N-isopropylmethacrylamide) (pNIPMAM) through free radical polymerization. The temperature induced transitions of colloidal suspensions of these nanoparticles were studied through a combination of differential scanning calorimetry (DSC), dynamic light scattering (DLS), and AC susceptibility measurements. In the pNIPAM coated nanoparticles excellent agreement was found for a transition temperature of approximately 30 degrees C by all three methods, although the AC susceptibility measurements indicated aggregation which was not evident from the DLS results. Small-angle neutron scattering (SANS) results obtained for pNIPAM coated nanoparticles confirmed that aggregation indeed occurs above the lower critical transition temperature of pNIPAM. For the pNIPMAM coated nanoparticles DLS and AC susceptibility measurements indicated aggregation at a temperature of approximately 33-35 degrees C, much lower than the transition temperature peak at 40 degrees C observed by DSC. However, the transition observed by DSC is very broad, hence it is possible that aggregation begins to occur at temperatures lower than the peak, as indicated by the AC susceptibility and DLS results. These experiments and observations demonstrate the possibility of using AC susceptibility measurements to probe transitions in colloidal suspensions induced by external stimuli. Because magnetic measurements do not require optical transparency, these

  4. Development of ac corona discharge modes at atmospheric pressure

    Corona discharges in gases exist under several distinctive forms. In this paper, a survey study has been made of ac corona discharge modes generated in some different gases fed in a wire-duct reactor with a constant rate of flowing at atmospheric pressure. The properties of different corona modes are analyzed under some condition transitions from Trichel pulses to a steady glow. In the course of the presented experimental work, numerous apparent contradictions with earlier observations necessitated further study and are given to provide more information on the physical mechanisms of the ac corona discharges. Furthermore, we have gained insight into some new technologies and applications of the environmentally friendly corona and plasma discharges.

  5. Performance of AC/graphite capacitors at high weight ratios of AC/graphite

    Wang, Hongyu [IM and T Ltd., Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan); Yoshio, Masaki [Advanced Research Center, Department of Applied Chemistry, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan)

    2008-03-01

    The effect of negative to positive electrode materials' weight ratio on the electrochemical performance of both activated carbon (AC)/AC and AC/graphite capacitors has been investigated, especially in the terms of capacity and cycle-ability. The limited capacity charge mode has been proposed to improve the cycle performance of AC/graphite capacitors at high weight ratios of AC/graphite. (author)

  6. Simultaneous distribution of AC and DC power

    Polese, Luigi Gentile

    2015-09-15

    A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.

  7. Assessing the allelotypic effect of two aminocyclopropane carboxylic acid synthase-encoding genes MdACS1 and MdACS3a on fruit ethylene production and softening in Malus

    Dougherty, Laura; Zhu, Yuandi; Xu, Kenong

    2016-01-01

    Phytohormone ethylene largely determines apple fruit shelf life and storability. Previous studies demonstrated that MdACS1 and MdACS3a, which encode 1-aminocyclopropane-1-carboxylic acid synthases (ACS), are crucial in apple fruit ethylene production. MdACS1 is well-known to be intimately involved in the climacteric ethylene burst in fruit ripening, while MdACS3a has been regarded a main regulator for ethylene production transition from system 1 (during fruit development) to system 2 (during fruit ripening). However, MdACS3a was also shown to have limited roles in initiating the ripening process lately. To better assess their roles, fruit ethylene production and softening were evaluated at five time points during a 20-day post-harvest period in 97 Malus accessions and in 34 progeny from 2 controlled crosses. Allelotyping was accomplished using an existing marker (ACS1) for MdACS1 and two markers (CAPS866 and CAPS870) developed here to specifically detect the two null alleles (ACS3a-G289V and Mdacs3a) of MdACS3a. In total, 952 Malus accessions were allelotyped with the three markers. The major findings included: The effect of MdACS1 was significant on fruit ethylene production and softening while that of MdACS3a was less detectable; allele MdACS1–2 was significantly associated with low ethylene and slow softening; under the same background of the MdACS1 allelotypes, null allele Mdacs3a (not ACS3a-G289V) could confer a significant delay of ethylene peak; alleles MdACS1–2 and Mdacs3a (excluding ACS3a-G289V) were highly enriched in M. domestica and M. hybrid when compared with those in M. sieversii. These findings are of practical implications in developing apples of low and delayed ethylene profiles by utilizing the beneficial alleles MdACS1-2 and Mdacs3a. PMID:27231553

  8. DC and AC transport properties on La0.8Sr0.2MnO3

    Zhantao Wei; Xinsheng Yang; Li Lv; Min Zhang; Yong Zhang

    2014-01-01

    Magnetoresistive sensor can be widely used in modern transportation field, such as the vehicle positioning and navigation system, vehicle detection system, and intelligent transportation system. In order to improve the efficiency of magnetoresistive sensor, we synthesized La0.8Sr0.2MnO3 polycrystalline bulks at different sintering temperatures and investigated their DC and AC transport properties in this work. As a result, all samples showed insulator-metal (I-M) phase transition, and the transition temperature (TI-M) shifted to higher temperature with the increase of sintering temperature. The TI-M measured at different AC frequencies was smaller than that measured at DC condition, which implied that the I-M phase transition was suppressed at AC frequencies. The resistivity mea-sured at high AC frequencies was larger than that measured at low AC frequencies, which could be attributed to the change of the magnetic penetration depth (d). However, the room-temperature AC-magnetoresistance (MR) at low frequencies was much larger than that at high frequencies and room-temperature DC-MR. These findings demon-strate that reducing the AC frequency is an effective way for enhancing the room-temperature MR, which can be used to promote the efficiency of magnetoresistive sensor.

  9. Electricity generation analyses in an oil-exporting country: Transition to non-fossil fuel based power units in Saudi Arabia

    In Saudi Arabia, fossil-fuel is the main source of power generation. Due to the huge economic and demographic growth, the electricity consumption in Saudi Arabia has increased and should continue to increase at a very fast rate. At the moment, more than half a million barrels of oil per day is used directly for power generation. Herein, we assess the power generation situation of the country and its future conditions through a modelling approach. For this purpose, we present the current situation by detailing the existing generation mix of electricity. Then we develop an optimization model of the power sector which aims to define the best production and investment pattern to reach the expected demand. Subsequently, we will carry out a sensitivity analysis so as to evaluate the robustness of the model's by taking into account the integration variability of the other alternative (non-fossil fuel based) resources. The results point out that the choices of investment in the power sector strongly affect the potential oil's exports of Saudi Arabia. For instance, by decarbonizing half of its generation mix, Saudi Arabia can release around 0.5 Mb/d barrels of oil equivalent per day from 2020. Moreover, total power generation cost reduction can reach up to around 28% per year from 2030 if Saudi Arabia manages to attain the most optimal generation mix structure introduced in the model (50% of power from renewables and nuclear power plants and 50% from the fossil power plants). - Highlights: • We model the current and future power generation situation of Saudi Arabia. • We take into account the integration of the other alternative resources. • We consider different scenarios of power generation structure for the country. • Optimal generation mix can release considerable amount of oil for export

  10. Fuel cell development for transportation: Catalyst development

    Doddapaneni, N. [Sandia National Lab., Albuquerque, NM (United States)

    1996-04-01

    Fuel cells are being considered as alternate power sources for transportation and stationary applications. With proton exchange membrane (PEM) fuel cells the fuel crossover to cathodes causes severe thermal management and cell voltage drop due to oxidation of fuel at the platinized cathodes. The main goal of this project was to design, synthesize, and evaluate stable and inexpensive transition metal macrocyclic catalysts for the reduction of oxygen and be electrochemically inert towards anode fuels such as hydrogen and methanol.

  11. Fuel and control for an integrated fuel cell system

    The OS/IES (On-Site Integrated Energy System) comprises a phosphoric acid fuel cell driven total energy package that produces electrical energy in the form of AC power (when the DC voltage from the fuel cell is inverted), and heat energy in the form of hot water. The fuel cell prefers a fuel high in hydrogen therefore it becomes necessary to convert as much of the fuel, i.e. natural or pipeline gas into hydrogen as possible using a fuel reformer. Fuel reforming is an endothermic process and in this case waste energy in the form of ''spent'' fuel from the fuel cell is used to supply heat to the reformer. Fuel cell waste heat is also used to raise the steam used in the reforming process. The OS/IES fuel processing system comprises five interrelated subsystems. Each subsystem is controlled independently through a microprocessor but a change in any subsystem function could have an effect on the operation of any or several other subsystems. Thus the controller receives a signal indicating electrical demand and proceeds to balance the subsystems as well as the fuel and air flow to each of the fuel cells. The controller also responds to a number of alarm signals and is capable of starting and stopping the complete OS/IES. It is assisted by a tie to the utility line which can dispense electrical energy for startup or instantaneous load following and accept excess generated power in case of load loss. In this paper we review fuel cell operation and requirements, the components and interactions that make up the reformer system, and the microprocessor control required to integrate the OS/IES

  12. AcEST: DK948526 [AcEST

    Full Text Available TST38A01NGRL0003_I19 675 Adiantum capillus-veneris mRNA. clone: TST38A01NGRL0003_I19. 5' end seq ... IAMVRTTTPVYV 214 Query: 542 ALALFNQARVSSLPIIDDNGSLIDIY ARSDITALARDDTY 661 AL +F Q RVS+LP++D+ G ++DIY ++ D+ ... LA + TY Sbjct: 215 ALGIFVQHRVSALPVVDEKGRVVDIY SKFDVINLAAEKTY 254 >sp|Q09138|AAKG1_PIG 5'-AMP-acti ... IAMVRTTTPVYV 215 Query: 542 ALALFNQARVSSLPIIDDNGSLIDIY ARSDITALARDDTY 661 AL +F Q RVS+LP++D+ G ++DIY ++ D+ ... LA + TY Sbjct: 216 ALGIFVQHRVSALPVVDEKGRVVDIY SKFDVINLAAEKTY 255 >sp|O54950|AAKG1_MOUSE 5'-AMP-ac ...

  13. AcEST: DK962916 [AcEST

    Full Text Available TST39A01NGRL0015_C06 596 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0015_C06. 5' end seq ... NA. clone: TST39A01NGRL0015_C06. 5' end sequence. Acce ssion DK962916 Tissue type prothallia with plantlet ... 2 Query: 317 MPKSKEPCSQEACDIQTCLVKNNFITERCFPVIEALQACCE K 442 MP+ K+PC ++AC+IQ CL NN++ +C VI+ L+ CC + Sbjct ... me = +2 Query: 335 PCSQEACDIQTCLVKNNFITERCFPVIEALQACCE K 442 PC +EAC IQ CL+ + + +C VI+ L CC K Sbjct: 4 PCQ ... = +2 Query: 326 SKEPCSQEACDIQTCLVKNNFITERCFPVIEALQACCE KCNSK 454 + E C+ CD +TC +K F +C AL CCE KC K Sbjct: 4 ...

  14. AcEST: DK955705 [AcEST

    Full Text Available TST39A01NGRL0023_N02 635 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0023_N02. 5' end seq ... NA. clone: TST39A01NGRL0023_N02. 5' end sequence. Acce ssion DK955705 Tissue type prothallia with plantlet ... 2 Query: 296 MPKSKEPCSQEACDIQTCLVKNNFITERCFPVIEALQACCE K 421 MP+ K+PC ++AC+IQ CL NN++ +C VI+ L+ CC + Sbjct ... me = +2 Query: 314 PCSQEACDIQTCLVKNNFITERCFPVIEALQACCE K 421 PC +EAC IQ CL+ + + +C VI+ L CC K Sbjct: 4 PCQ ... = +2 Query: 305 SKEPCSQEACDIQTCLVKNNFITERCFPVIEALQACCE KCNSK 433 + E C+ CD +TC +K F +C AL CCE KC K Sbjct: 4 ...

  15. AcEST: DK961330 [AcEST

    Full Text Available FWVPCMHTPIKQEKHTHA 405 +AR P W +++PI+ ++C++ P + AK+ PL DVTH+F+V + +QE Sbjct: 61 VARRTRP-SWHEDNPINYVQCDISDPDD...+IL +D PGGPWKVYG Sbjct: 4 WWAGAIGAAKKKLEEDDAPPKHS---SVALIVGVTGIIGNSLAEILPLADTPGGP...AWHEDNPINYIQCDISDPDDSLAKLSPLTDVTHVFYVTCANR--STEPENCE 117 Query: 406 MATHMFENIIGVLLTHAPNLQHVCMQTSDKHY-... : Swiss-Prot sp_hit_id Q7MXT7 Definition sp|Q7MXT7|LPXD_PORGI UDP-3-O-[3-hydroxymyristoyl] glucosamine N-ac...lue sp|Q7MXT7|LPXD_PORGI UDP-3-O-[3-hydroxymyristoyl] glucosamine N-... 34 0.62 sp|P60369|KR103_HUMAN Kerati

  16. AcEST: BP913772 [AcEST

    Full Text Available N VT V L C+ G G+ H Sbjct: 350 NVVTWSAVIAGYAQRGLGFEALDVFRQMRLCGSEPNVVTLVSLLSGCALAGTLLHGKETH 409 Query: 376 IEIER--RGLLEVDP-...VFNKLSVQDIVSW 236 + + A ++G+++H I RRGL + PV+ + LV MY R G L Q VF+++ +D+VSW Sbjct: 296 ASLAALEQGKLIHGYILRRGLDSILPVI-S... TF M+ +PN+VT V VL+AC+ + Q + Sbjct: 250 SWSAMIACYAKNGKAFEALRTFREMMRETKDSSPNSVTMVSVLQACASLA...MIEGGVAPNAVTFVVVLRACSQTGSYSQSQTFFEAMSKNF 50 + G A G + F+ M + GV PNAVTFV VLR CS G + Q F++M F Sbjct: 312 ALNGLAMNGFGEKCLELFSL...L YA G + + +F++ D+ +TA + + Sbjct: 48 IHAAILRHNLLLHPRYPVLNLKLHRAYASHGKIRHSLALFHQTIDP

  17. AcEST: DK952954 [AcEST

    Full Text Available TST38A01NGRL0015_H21 616 Adiantum capillus-veneris mRNA. clone: TST38A01NGRL0015_H21. 5' end seq ... LIHAHIVCSCNDVDNFVRSTLVNLYSKCGSIEDAHNVFAKLATRRSVDWSMMIS ... 541 ++ Q K +HA I + D + V + L+++Y+KCGSI DA F +++T+ ... LIHAHIVCSCNDVDNFVRSTLVNLYSKCGSIEDAHNVFAKLATRRSVDWSMMIS GS 547 + + IHA S D ++ LV LYS+CG IE+++ F + ++ W+ ++S ... LIHAHIVCSCNDVDNFVRSTLVNLYSKCGSIEDAHNVFAKLATRRSVDWSMMIS ... 541 DL + IH+ I+ + ++ +V S L+++Y+K G ++ A ++ + A + ... EA+ LF +M G+ P + + L AC Sbjct: 243 RVFDGLRLKDHSSWVAMIS GLSKNECEAEAIRLFCDMYVLGIMPTPYAFSSVLSACKKIE 302 Query ...

  18. AcEST: BP912540 [AcEST

    Full Text Available YMU001_000020_B03 501 Adiantum capillus-veneris mRNA. clone: YMU001_000020_B03. BP912540 - Show ... 2 EELTVHHTASVGDVEALKALLAEGADKDEKDSEGRTALHFACGYGEVMCAE VLLEAGVAV 181 EE VH TAS+GDVE LKA LA G +KDE+DSEGRTAL ... ry: 14 VHHTASVGDVEALKALLAEGADKDEKDSEGRTALHFACGYGEVMCAE VLLEAGVAVDAVD 193 +H A V ++ LL GAD KD G LH AC YG AE ... uery: 26 ASVGDVEALKALLAEGADKDEKDSEGR--TALHFACGYGEVMCAE VLLEAGVAVDAVDKN 199 + GD+E +K L + + + +D EGR T LHFA ... ry: 14 VHHTASVGDVEALKALLAEGADKDEKDSEGRTALHFACGYGEVMCAE VLLEAGVAVDAVD 193 +H A ++E + LL GAD + +D G LH A YG ...

  19. Long-Term Performance of Chemically and Physically Modified Activated Carbons in Air Cathodes of Microbial Fuel Cells

    Zhang, Xiaoyuan

    2014-07-31

    © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Activated carbon (AC) is a low-cost and effective catalyst for oxygen reduction in air cathodes of microbial fuel cells (MFCs), but its performance must be maintained over time. AC was modified by three methods: 1)pyrolysis with iron ethylenediaminetetraacetic acid (AC-Fe), 2)heat treatment (AC-heat), and 3)mixing with carbon black (AC-CB). The maximum power densities after one month with these AC cathodes were 35% higher with AC-Fe (1410±50mW m-2) and AC-heat (1400±20mW m-2), and 16% higher with AC-CB (1210±30mW m-2) than for plain AC (1040±20mW m-2), versus 1270±50mW m-2 for a Pt control. After 16months, the Pt cathodes produced only 250±10mW m-2. However, the AC-heat and AC-CB cathodes still produced 960-970mW m-2, whereas plain AC produced 860±60mW m-2. The performance of the AC cathodes was restored to >85% of the initial maximum power densities by cleaning with a weak acid solution. Based on cost considerations among the AC materials, AC-CB appears to be the best choice for long-term performance.

  20. A catalyst layer optimisation approach using electrochemical impedance spectroscopy for PEM fuel cells operated with pyrolysed transition metal-N-C catalysts

    Malko, Daniel; Lopes, Thiago; Ticianelli, Edson A.; Kucernak, Anthony

    2016-08-01

    The effect of the ionomer to carbon (I/C) ratio on the performance of single cell polymer electrolyte fuel cells is investigated for three different types of non-precious metal cathodic catalysts. Polarisation curves as well as impedance spectra are recorded at different potentials in the presence of argon or oxygen at the cathode and hydrogen at the anode. It is found that a optimised ionomer content is a key factor for improving the performance of the catalyst. Non-optimal ionomer loading can be assessed by two different factors from the impedance spectra. Hence this observation could be used as a diagnostic element to determine the ideal ionomer content and distribution in newly developed catalyst-electrodes. An electrode morphology based on the presence of inhomogeneous resistance distribution within the porous structure is suggested to explain the observed phenomena. The back-pressure and relative humidity effect on this feature is also investigated and supports the above hypothesis. We give a simple flowchart to aid optimisation of electrodes with the minimum number of trials.

  1. Speed Control of DC Motor using AC/AC/DC Converter Based on Intelligent Techniques

    Rakan Kh Antar

    2013-01-01

       This paper describes the application of ac/ac/dc and ac/dc converters to control the speed of a separately excited DC motor. Artificial neural network and PI controller are trained to select the desired values of firing angles for triggering thyristors of the ac/ac/dc and ac/dc bridge converters in order to control the speed of the dc motor at a desired value with constant and different load torques in order to obtain the best speed response. Simulation results show that the rising time fo...

  2. Shape Dependence of Low-Temperature Magnetic Relaxation of Mn12Ac

    LIU Hai-Qing; SU Shao-Kui; JING Xiu-nian; LIU Ying; LI Yan-rong; HE Lun-Hua; GE Pei-Wen; YAN Qi-Wei; WANG Yun-Ping

    2008-01-01

    We report the discovery that the low-temperature magnetic relaxation in Mn,12 Ac single crystals strongly depends on the shape of the samples. The relaxation time exhibits a minimum at the phase transition point between ferromagnetic and antiferromagnetic phases. The shape dependence is attributed to the dipolar interaction between molecular magnets.

  3. Temperature and frequency dependence of AC conductivity of new quaternary Se-Te-Bi-Pb chalcogenide glasses

    Yadav, Preeti; Sharma, Ambika

    2016-05-01

    The aim of the present work is to study the temperature and frequency dependence of ac conductivity of new quaternary Se84-xTe15Bi1.0Pbx chalcogenide glasses. The Se84-xTe15Bi1.0Pbx (x = 2, 6) glassy alloys are prepared by using melt quenching technique. The temperature and frequency dependent behavior of ac conductivity σac(ω) has been carried out in the frequency range 42 Hz to 5 MHz and in the temperature range of 298-323 K below glass transition temperature. The behavior of ac conductivity is described in terms of the power law ωs. The obtained temperature dependence behavior of ac conductivity and frequency component (s) are explained by means of correlated barrier hopping model recommended by Elliot.

  4. Universality of ac conduction in disordered solids

    Dyre, Jeppe; Schrøder, Thomas

    2000-01-01

    non-power-law universalities. It is argued that ac universality reflects an underlying percolation determining dc as well as ac conductivity in the extreme disorder limit. Three analytical approximations to the universal ac conductivities are presented and compared to computer simulations. Finally......The striking similarity of ac conduction in quite different disordered solids is discussed in terms of experimental results, modeling, and computer simulations. After giving an overview of experiment, a macroscopic and a microscopic model are reviewed. For both models the normalized ac conductivity...... as a function of a suitably scaled frequency becomes independent of details of the disorder in the extreme disorder limit, i.e., when the local randomly varying mobilities cover many orders of magnitude. The two universal ac conductivities are similar, but not identical; both are examples of unusual...

  5. Solid Oxide Fuel Cell

    2010-01-01

    The solid oxide fuel cell comprising a metallic support material, an active anode layer consisting of a good hydrocarbon cracking catalyst, an electrolyte layer, an active cathode layer, and a transition layer consisting of preferably a mixture of LSM and a ferrite to the cathode current collector...

  6. Fuel assembly

    Purpose: To improve the thermal and mechanical safety of fuel rods and structural components by making the local power coefficient of jointed fuel rods greater than that of other fuel rods in a fuel assembly. Constitution: In a fuel assembly comprising a plurality of fuel rods bundled by a spacer and held at the upper and the lower positions with tie plates for insertion into a channel, the degree of enrichment of uranium 235 for uranium dioxide fuel pellets charged in jointed fuel rods is adjusted such that the local power coefficient of the jointed fuel rods is made greater than that of the other fuel rods. In the case if the upper tie plate is moved upwardly by the extension of the jointed fuel rods, other fuel rods axially free from the upper tie plate receives no tension, whereby the safety of the fuel assembly can be improved. (Moriyama, K.)

  7. Short term dynamic aperture with AC dipoles

    Mönig, Saskia; Persson, Tobias Hakan Bjorn; Coello De Portugal, Jaime; Langner, Andy; Tomas, Rogelio; CERN. Geneva. ATS Department

    2015-01-01

    The dynamic aperture of an accelerator is determined by its non-linear components and errors. Control of the dynamic aperture is important for a good understanding and operation of the accelerator. The AC dipole, installed in the LHC for the diagnostic of linear and non-linear optics, could serve as a tool for the determination of the dynamic aperture. However, since the AC dipole itself modifies the non-linear dynamics, the dynamic aperture with and without AC dipole are expected to differ. The effect of the AC dipole on the dynamic aperture is studied within this note.

  8. ac electroosmosis in rectangular microchannels.

    Campisi, Michele; Accoto, Dino; Dario, Paolo

    2005-11-22

    Motivated by the growing interest in ac electroosmosis as a reliable no moving parts strategy to control fluid motion in microfluidic devices for biomedical applications, such as lab-on-a-chip, we study transient and steady-state electrokinetic phenomena (electroosmosis and streaming currents) in infinitely extended rectangular charged microchannels. With the aid of Fourier series and Laplace transforms we provide a general formal solution of the problem, which is used to study the time-dependent response to sudden ac applied voltage differences in case of finite electric double layer. The Debye-Huckel approximation has been adopted to allow for an algebraic solution of the Poisson-Boltzmann problem in Fourier space. We obtain the expressions of flow velocity profiles, flow rates, streaming currents, as well as expressions of the complex hydraulic and electrokinetic conductances. We analyze in detail the dependence of the electrokinetic conductance on the extension of linear dimensions relative to the Debye length, with an eye on finite electric double layer effects. PMID:16351310

  9. DESARROLLO RURAL A.C.

    Alfredo Aguilar Valdés

    2015-01-01

    Full Text Available El objetivo de este trabajo fue analizar el diagnostico situacional de una Empresa de Servicios Profesionales en el caso de: Instituto de Promoción Para el Desarrollo Rural A.C., a través de la Metodología “UALAE” así como la oportunidad que como empresa presenta. Este estudio se realizó en el municipio de Saltillo, Coahuila, México. Adoptó esta Metodología UALAE y se difundió su opinión. El Instituto de Promoción Para el Desarrollo Rural A.C., está formado por profesionistas y productores cuya finalidad es la de contribuir al desarrollo del medio rural con proyectos de viabilidad técnica, económica y social, sobre la base de necesidades reales y al aprovechamiento sustentable del potencial de los recursos naturales. Su buen funcionamiento es indispensable e importante para el desarrollo de los productores agropecuarios principalmente, debido a que se ven muy beneficiados con todos los servicios que se les brinda, se han logrado buenos proyectos, buenas capacitaciones y un gran crecimiento de sus productos. Mediante el proceso de asistencia técnica a organizaciones de productores, se induce la formulación adecuada de proyectos viables desde el punto visto del mercado, la rentabilidad económica, las tecnologías disponibles y de la organización social.

  10. High Efficiency Reversible Fuel Cell Power Converter

    Pittini, Riccardo

    traditional unidirectional fuel cell, bidirectional fuel cells have increased operating voltage and current ranges. These characteristics increase the stresses on dc-dc and dc-ac converters in the electrical system, which require proper design and advanced optimization. This work is part of the PhD project......The large scale integration of renewable energy sources requires suitable energy storage systems to balance energy production and demand in the electrical grid. Bidirectional fuel cells are an attractive technology for energy storage systems due to the high energy density of fuel. Compared to...... entitled "High Efficiency Reversible Fuel Cell Power Converter" and it presents the design of a high efficiency dc-dc converter developed and optimized for bidirectional fuel cell applications. First, a brief overview of fuel cell and energy storage technologies is presented. Different system topologies as...

  11. Fuel Pathway Integration Technical Team Roadmap

    None

    2013-06-01

    The Fuel Pathway Integration Technical Team (FPITT) supports the U.S. DRIVE Partnership (the Partnership) in the identification and evaluation of implementation scenarios for fuel cell technology pathways, including hydrogen and fuel cell electric vehicles in the transportation sector, both during a transition period and in the long term.

  12. AcEST: BP920845 [AcEST

    Full Text Available 45|Adiantum capillus-veneris mRNA, clone: YMU001_000142_D08. (514 letters) Database: uniprot_sprot.fasta 412,525 seq...P7 OS=Magnapor... 33 1.0 sp|Q7VF68|SYH_HELHP Histidyl-tRNA synthetase OS=Helicobacter hep... 31 3.8 sp|P1305...90 FTGFLVLHSEPRQQPQVDL 1608 >sp|A4QX49|DBP7_MAGGR ATP-dependent RNA helicase DBP7 OS=Magnaporthe grise...T PT VT+H + T+ AC+ A+TT+ H H Sbjct: 481 PPKETKPTK------PVTNHTESTVGKACYITSAANTTITLHKLH 519 >sp|Q7VF68|SYH_HELHP His...rot_trembl.fasta 7,341,751 sequences; 2,391,615,440 total letters Searching.................................

  13. AcEST: DK960083 [AcEST

    Full Text Available ome P450 71D7 OS=Solanum chacoense ... 96 1e-19 sp|Q9SAB6|C71AI_ARATH Cytochrome ...... 96 2e-19 sp|P93530|C71D6_SOLCH Cytochrome P450 71D6 OS=Solanum chacoense ... 94 5e-19 sp|Q9T0K2|C71AK_AR... paten... 176 1e-42 tr|Q9AXP9|Q9AXP9_POPJC Cinnamate 4-hydroxylase OS=Populus jackii... 176 2e-42 tr|Q40907|Q40907_POPKI Cinnamic ac...8 KVVQQSRGAWEDEALRVIQDLKA 160 >tr|Q9AXP9|Q9AXP9_POPJC Cinnamate 4-hydroxylase OS=Populus jackii GN=C4H PE=2 ...e-42 tr|A9PBZ7|A9PBZ7_POPTR Putative uncharacterized protein OS=Popul... 176 2e-4

  14. AcEST: DK955376 [AcEST

    Full Text Available TST39A01NGRL0022_O23 611 Adiantum capillus-veneris mRNA. clone: TST39A01NGRL0022_O23. 5' end seq ... LMDETRAAGIKL 210 Query: 602 AIC 610 A+C Sbjct: 211 AVC ... 213 >tr|A9SM81|A9SM81_PHYPA Predicted protein OS=P ... C 610 VLELMD A+ KGLKVA+C Sbjct: 196 VLELMDAAREKGLKVAVC ... 213 >tr|Q8L7U1|Q8L7U1_ARATH AT4g39970/T5J17_140 OS ... LKVAIC 610 LMDEA+A G K+A+C Sbjct: 182 RLMDEAKAAGKKLAVC ... 197 >tr|Q680K2|Q680K2_ARATH MRNA, complete cds, cl ... LKVAIC 610 LMDEA+A G K+A+C Sbjct: 182 RLMDEAKAAGKKLAVC ... 197 >tr|Q8LAS1|Q8LAS1_ARATH Putative uncharacteriz ...

  15. AcEST: BP913416 [AcEST

    Full Text Available GCATGTAGTTTGGA CAGAGATG ■■Homology search results ■■ - Swiss-Prot (release 56.9) Link to BlastX Result : Swi...AC_BACFN Uronate isomerase OS=Bacteroides fragilis (... 30 4.5 sp|Q3ITT7|SYA_NATPD Alanyl-tRNA synthetase OS=Natronomonas phar...C++ N IP+ M C Sbjct: 417 LSYPRHEYFRRTLCNLLGCDVENGEIPLSEMERVC 451 >sp|Q3ITT7|SYA_NATPD Alanyl-tRNA synthetase OS=Natronomonas phar...ng, Webb Miller, and David J. Lipman (1997), Gapped BLAST and PSI-BLAST: a new generation of protein database searc...148,809,765 total letters Searching..................................................done Score E Sequences

  16. AcEST: DK947388 [AcEST

    Full Text Available Lipman (1997), Gapped BLAST and PSI-BLAST: a new generation of protein database search programs, Nucleic Ac...ids Res. 25:3389-3402. Query= DK947388|Adiantum capillus-veneris mRNA, clone: YMU02A01NGRL0015_L18, 5' (587 letters) Databa... generation of protein database search programs, Nucleic Acids Res. 25:3389-3402. Query= DK947388|Adiantum c...apillus-veneris mRNA, clone: YMU02A01NGRL0015_L18, 5' (587 letters) Database: uniprot_trembl.fasta...-ribosylation factor 1 OS=Salix bakko GN... 268 1e-71 sp|P49076|ARF_MAIZE ADP-ribosylation factor OS=Zea may

  17. AcEST: BP916217 [AcEST

    Full Text Available inase kinase 7-interacting protein 3 OS=Mus musculus Align length 119 Score (bit) 35.0 E-value 0.16 Report B...visiae GN... 30 6.8 >sp|Q571K4|TAB3_MOUSE Mitogen-activated protein kinase kinase kinase 7-interacting protein 3 OS=Mus musculus...protein kinase kinase kinase 7 interacting protein 3 OS=Mus musculus GN=Map3k7ip3 PE=2 SV=1 Length = 716 Sco...(3)malignant brain tumor-like 2 prot... 31 2.3 sp|P33234|ADIY_ECOLI HTH-type transcriptional regulator adiY ...ZZC3_PSEU2 Membrane protein, putative OS=Pseudomonas... 35 2.5 tr|Q5U7D5|Q5U7D5_9BACI OpuAC OS=Halobacillus trueperi GN=opu

  18. AcEST: DK953324 [AcEST

    Full Text Available |LSRR_PHOLL Transcriptional regulator lsrR OS=Photorhab... 30 6.1 sp|A0JY64|ATPB_ARTS2 ATP synthase subunit beta OS=Arthroba...cter s... 30 6.1 sp|A1R7V3|ATPB_ARTAT ATP synthase subunit beta OS=Arthroba...ATP synthase subunit beta OS=Arthrobacter sp. (strain FB24) GN=atpD PE=3 SV=1 Len...KD 372 Query: 311 HLHFTHRGKQRL 346 H + R KQ L Sbjct: 373 HYNTAVRVKQIL 384 >sp|A1R7V3|ATPB_ARTAT ATP synthase subunit beta OS=Arthroba...T and PSI-BLAST: a new generation of protein database search programs, Nucleic Ac

  19. AcEST: DK945049 [AcEST

    Full Text Available R 148 >sp|Q9X5X3|ATCU_SINMW Copper-transporting P-type ATPase OS=Sinorhizobium medicae (strain WSM419) GN=ac...|Q4EPP8|Q4EPP8_LISMO Heavy metal-binding protein OS=Listeria m... 34 3.2 tr|A6AST1|A6AST1_VIBHA Copper-trans..... 31 2.7 sp|Q4X0S7|DPH1_ASPFU Diphthamide biosynthesis protein 1 OS=Asper... 30 4.5 sp|A2VDJ0|T131L_HUMAN Transmembran...P58342|ATCU2_RHIME Copper-transporting ATPase 2 OS=Rhizobium meliloti Align length 75 Score (bit) 34.7 E-val...sophila ... 30 7.8 >sp|P58342|ATCU2_RHIME Copper-transporting ATPase 2 OS=Rhizobium me

  20. Fessenheim: 30 years of nuclear fuel operation

    Fessenheim units 1 and 2 are the first two 900 MW PWR put into operation in France (1977). This article reviews 30 years of change, optimization and feedback experience from Fessenheim, concerning: -) fuel assemblies (particularly the design of some components like grids, ends and guide tubes), -) the reload fuel management (to get a higher unloading burn-up), -) the refueling machine and tools (heavy modifications to reduce the human factor), and -) work organization (work shifts and staff training). (A.C.)

  1. DIAGNOSTIC FEATURES RESEARCH OF AC ELECTRIC POINT MOTORS

    S. YU. Buryak

    2014-05-01

    Full Text Available Purpose.Considerable responsibility for safety of operation rests on signal telephone and telegraph department of railway. One of the most attackable nodes (both automation systems, and railway in whole is track switches. The aim of this investigation is developing such system for monitoring and diagnostics of track switches, which would fully meet the requirements of modern conditions of high-speed motion and heavy trains and producing diagnostics, collection and systematization of data in an automated way. Methodology. In order to achieve the desired objectives research of a structure and the operating principle description of the switch electric drive, sequence of triggering its main units were carried out. The operating characteristics and settings, operating conditions, the causes of failures in the work, andrequirements for electric drives technology and their service were considered and analyzed. Basic analysis principles of dependence of nature of the changes the current waveform, which flows in the working circuit of AC electric point motor were determined. Technical implementation of the monitoring and diagnosing system the state of AC electric point motors was carried out. Findings. Signals taken from serviceable and defective electric turnouts were researched. Originality. Identified a strong interconnectionbetween the technical condition of the track switchand curve shape that describes the current in the circuit of AC electric point motor during operation which is based on the research processes that have influence on it during operation. Practical value. Shown the principles of the technical approach to the transition from scheduled preventive maintenance to maintenance of real condition for a more objective assessment and thus more rapid response to emerging or failures when they occur gradually, damages and any other shortcomings in the work track switch AC drives.

  2. Alcohol fuels

    1980-01-01

    This issue is devoted almost entirely to alcohol fuels, the following topics being presented: A History of Alcohol Fuels; In the Midwest - Focus on Alcohol Fuels; Gasohol - A DOE Priority; Alcohol Fuels Potential; Gasohol - The Nutritious Fuel; Energy from Agriculture; Alcohol and the Price of Food; A New Look at Economics and Energy Balance in Alcohol Production; Economics of small-scale alcohol producers; Get the Lead Out with Alcohol; Biomass and the Carbon Dioxide Buildup; Federal Agency Activity in Alcohol Fuels; Congressional Activity in Alchol Fuels; Licensing a Small Still; Funding Sources for Alcohol Facilities; Safety in Alcohol Production; Alcohol Fuels Information; State-by-State Guide to Alcohol Activity; Alcohol Fuels Glossary; Alcohol Fuels and Your Car; Alcohol Fuels Training Grants Progam; Citizen Action Plan for Gasohol; and Alcohol Fuels - a Path to Reconciliation.

  3. The Ethylene Biosynthesis Gene CitACS4 Regulates Monoecy/Andromonoecy in Watermelon (Citrullus lanatus)

    Manzano, Susana; Aguado, Encarnación; Martínez, Cecilia; Megías, Zoraida; García, Alicia; Jamilena, Manuel

    2016-01-01

    Monoecious and andromonoecious cultivars of watermelon are characterised by the production of male and female flower or male and hermaphrodite flowers, respectively. The segregation analysis in the offspring of crosses between monoecious and andromonoecious lines has demonstrated that this trait is controlled by a single gene pair, being the monoecious allele M semi-dominant to the andromonoecious allele A. The two studied F1 hybrids (MA) had a predominantly monoecious phenotype since both produced not only female flowers, but also bisexual flowers with incomplete stamens, and hermaphrodite flowers with pollen. Given that in other cucurbit species andromonoecy is conferred by mutations in the ethylene biosynthesis genes CmACS7, CsACS2 and CpACS27A we have cloned and characterised CitACS4, the watermelon gene showing the highest similarity with the formers. CitACS4 encoded for a type ACS type III enzyme that is predominantly expressed in pistillate flowers of watermelon. In the andromonoecious line we have detected a missense mutation in a very conserved residue of CitACS4 (C364W) that cosegregates with the andromonoecious phenotype in two independent F2 populations, concomitantly with a reduction in ethylene production in the floral buds that will develop as hermaphrodite flowers. The gene does not however co-segregates with other sex expression traits regulated by ethylene in this species, including pistillate flowering transition and the number of pistillate flowers per plant. These data indicate that CitAC4 is likely to be involved in the biosynthesis of the ethylene required for stamen arrest during the development of female flowers. The C364W mutation would reduce the production of ethylene in pistillate floral buds, promoting the conversion of female into hermaphrodite flowers, and therefore of monoecy into andromonoecy. PMID:27149159

  4. Fuel assembly

    A fuel assembly of a BWR type reactor comprises a rectangular parallelopiped channel box and fuel bundles contained in the channel box. The fuel bundle comprises an upper tie plate, a lower tie plate, a plurality of spacers a plurality of fuel rods and a water rod. In each fuel rod, the amount of fission products is reduced at upper and lower end regions of an effective fuel portion than that in other regions of the effective fuel region. In a portion of the fuel rods, fuel pellets containing burnable poisons are disposed at the upper and lower end regions. In addition, the upper and lower portions are constituted with natural uranium. Each of the upper and lower end regions is not greater than 15% of the effective fuel length. Since this can enhance reactivity control effect without worsening fuel economy, the control amount for excess reactivity upon long-term cycle operation can be increased. (I.N.)

  5. Hawaiian hydrogen mass transit system

    This paper proposes a joint effort between the scientific and business communities; to create, make and have hydrogen fuel become the primary fuel of the future. Hawaii has abundant, unharnessed renewable resources yet imports almost all of its fuel. Initiating hydrogen production and industrial application in conjunction with a prototype pilot project such as this mass transit system would not only accomplish the joining of science and business but give an environmentally safe energy alternative to the state and people of Hawaii and hopefully the world

  6. SINGLE PHASE HIGH FREQUENCY AC CONVERTER FOR INDUCTION HEATING APPLICATION

    M.A INAYATHULLAAH,; Dr. R. Anita

    2010-01-01

    The proposed topology reduces the total harmonic distortion (THD) of a high frequency AC/AC Converter well below the acceptable limit. This paper deals with a novel single phase AC/DC/AC soft switching utility frequency AC to high frequency AC converter. In this paper a single phase full bridge inverter with Vienna rectifier as front end is used instead of conventional diode bridge rectifier to provide continuous sinusoidal input current with nearly unity power factor at the source side with ...

  7. Structure and relaxation dynamics of poly(amide urethane)s with bioactive transition metal acetyl acetonates in hard blocks.

    Kalogeras, I M; Roussos, M; Vassilikou-Dova, A; Spanoudaki, A; Pissis, P; Savelyev, Y V; Shtompel, V I; Robota, L P

    2005-12-01

    Structural characteristics, thermal transitions and molecular dynamics of selected poly(amide urethane)s with transition metal acetyl acetonates Me(AcAc)(2) (Me = Sn(4+), Zn(2+), Cu(2+), Pb(2+)) as chain extenders, were comparatively investigated using small- and wide-angle X-ray scattering (SAXS, WAXS), differential scanning calorimetry (DSC), and dielectric techniques (dielectric relaxation spectroscopy, DRS; thermally stimulated currents, TSC). We studied the influence of metal chelates on the mixing of the soft-segment (SS) and hard-segment (HS) domains and the related degree of microphase separation (DMS). The reactivity of Me(AcAc)(2) with macrodiisocyanate was found to decrease in the order Sn(AcAc)(2)Cl(2) > Cu(AcAc)(2) > Zn(AcAc)(2) > Pb(AcAc)(2). While Pb(AcAc)(2) shows a higher tendency for crystallisation, both the dielectric and calorimetric results suggest that the corresponding polyurethane has comparatively low DMS. The type of the transition metal has moderate effect on the glass transition temperature and no influence on the shape of the dielectric alpha relaxation signal, indicating weak interactions between metal ions and SS domains. In contrast, structural parameters and the dielectric behaviour of the beta relaxation suggest preference for hydrogen-bonding interactions between Sn(4+) and Cu(2+) metal-chelates and HS domains. The temperature dependence of dc conductivity sigma(dc) is described by the Vogel-Tammann-Fulcher equation and signifies the coupling between the mobility of polymeric chains and charges' motion. It may be expected that the present combination of techniques and particular results with respect to DMS will contribute to the development and testing of novel biodegradation-resistant and antibacterial metal-polyurethanes for biotechnological and industrial applications. PMID:16331340

  8. Electric field in an AC dielectric barrier discharge overlapped with a nanosecond pulse discharge

    Goldberg, Benjamin M.; Shkurenkov, Ivan; Adamovich, Igor V.; Lempert, Walter R.

    2016-08-01

    The effect of ns discharge pulses on the AC barrier discharge in hydrogen in plane-to-plane geometry is studied using time-resolved measurements of the electric field in the plasma. The AC discharge was operated at a pressure of 300 Torr at frequencies of 500 and 1750 Hz, with ns pulses generated when the AC voltage was near zero. The electric field vector is measured by ps four-wave mixing technique, which generates coherent IR signal proportional to the square of electric field. Absolute calibration was done using an electrostatic (sub-breakdown) field applied to the discharge electrodes, when no plasma was generated. The results are compared with one-dimensional kinetic modeling of the AC discharge and the nanosecond pulse discharge, predicting behavior of both individual micro-discharges and their cumulative effect on the electric field distribution in the electrode gap, using stochastic averaging based on the experimental micro-discharge temporal probability distribution during the AC period. Time evolution of the electric field in the AC discharge without ns pulses, controlled by a superposition of random micro-discharges, exhibits a nearly ‘flat top’ distribution with the maximum near breakdown threshold, reproduced quite well by kinetic modeling. Adding ns pulse discharges on top of the AC voltage waveform changes the AC discharge behavior in a dramatic way, inducing transition from random micro-discharges to a more regular, near-1D discharge. In this case, reproducible volumetric AC breakdown is produced at a well-defined moment after each ns pulse discharge. During the reproducible AC breakdown, the electric field in the plasma exhibits a sudden drop, which coincides in time with a well-defined current pulse. This trend is also predicted by the kinetic model. Analysis of kinetic modeling predictions shows that this effect is caused by large-volume ionization and neutralization of surface charges on the dielectrics by ns discharge pulses. The present

  9. Fuel assembly

    Object: To divide fuel rods into several blocks so that fuels may be reversed vertically every block to leave sufficient allowance for reactor stoppage, thus enhancing taking-out combustion quality. Structure: A fuel inserting portion in upper and lower tie plates is designed so that a vertically symmetrical fuel may be inserted. That is, the construction of the fuel rod itself is entirely vertically symmetrical. Fuel regions are symmetrically arranged on uppper and lower ends, and expansion springs are also inserted at upper and lower parts. Outer springs of the fuel rods are always retained at plug portions on upper and lower ends. The fuel rods are of the sub-channel construction consisting of several rods, the fuel rods being separable from one another every sub-channel. Accordingly, the fuel may be reversed every sub-channel. (Kamimura, M.)

  10. Contribution to the study of {sup 233}U production with MOX-ThPu fuel in PWR reactor. Transition scenarios towards Th/{sup 233}U iso-generating concepts in thermal spectrum. Development of the MURE fuel evolution code; Contribution a l'etude de la production d'{sup 233}U en combustible MOX-ThPu en reacteur a eau sous pression. Scenarios de transition vers des concepts isogenerateurs Th/{sup 233}U en spectre thermique. Developpement du code MURE d'evolution du combustible

    Michel-Sendis, F

    2006-12-15

    If nuclear power is to provide a significant fraction of the growing world energy demand, only through the breeding concept can the development of sustainable nuclear energy become a reality. The study of such a transition, from present-day nuclear technologies to future breeding concepts is therefore pertinent. Among these future concepts, those using the thorium cycle Th/U-233 in a thermal neutron spectrum are of particular interest; molten-salt type thermal reactors would allow for breeding while requiring comparatively low initial inventories of U-233. The upstream production of U-233 can be obtained through the use of thorium-plutonium mixed oxide fuel in present-day light water reactors. This work presents, firstly, the development of the MURE evolution code system, a C++ object-oriented code that allows the study, through Monte Carlo (M.C.) simulation, of nuclear reactors and the evolution of their fuel under neutron irradiation. The M.C. methods are well-suited for the study of any reactor, whether it'd be an existing reactor using a new kind of fuel or a future concept altogether, the simulation is only dependent on nuclear data. Exact and complex geometries can be simulated and continuous energy particle transport is performed. MURE is an interface with MCNP, the well-known and validated transport code, that allows, among other functionalities, to simulate constant power and constant reactivity evolutions. Secondly, the study of MOX ThPu fuel in a conventional light water reactor (REP) is presented; it explores different plutonium concentrations and isotopic qualities in order to evaluate their safety characteristics. Simulation of their evolution allows us to quantify the production of U-233 at the end of burnup. Last, different french scenarios validating a possible transition towards a park of thermal Th/U-233 breeders, are presented. In these scenarios, U-233 is produced in ThPu moxed light water reactors. (author)

  11. 78 FR 3853 - Retrievability, Cladding Integrity and Safe Handling of Spent Fuel at an Independent Spent Fuel...

    2013-01-17

    ... Independent Spent Fuel Storage Installation and During Transportation AGENCY: Nuclear Regulatory Commission... transport of spent nuclear fuel are separate from requirements for storage of spent nuclear fuel. Because... transition from storage to transport by potentially minimizing future handling of spent fuel and......

  12. Characterization of AcMNPV with a deletion of ac69 gene

    Jianhao Ke

    2011-07-01

    Full Text Available ORF69 (Ac69 of Autographa californica multiple nucleopolyhedrovirus (AcMNPV is conserved in some baculovirus genomes. Although it has been shown that Ac69 has cap 0-dependent methyltransferase activity and is not required for budded virus production in Spodoptera frugiperda Sf-9 cells, its role in occlusion-derived virus synthesis and virus oral infectivity is not known. This paper describes generation of an ac69 knockout AcMNPV bacmid mutant and analyses of the influence of ac69 deletion on the viral infectivity in Sf-9 cells and Trichoplusia ni larvae so as to investigate the role of ac69 in the viral life cycle. Results indicated that ac69 deletion has little effect on the production rates and morphogenesis of budded virus and occlusion-derived virus in Sf-9 cells. In addition, animal experiment revealed that the deletion mutant did not affect AcMNPV infectivity for Trichoplusia ni larvae in LD50 and LT50 bioassay when administered orally. These results suggest that ac69 may be dispensable for viral infectivity both in vitro and in vivo.

  13. Novel power electronic interface for grid-connected fuel cell power generation system

    Highlights: • A fuel cell power generation system was composed of a DC–DC power converter and a DC–AC inverter. • A voltage doubler based topology was adopted to configure the DC–DC power converter. • A dual buck power converter and a full-bridge power converter were applied to the DC–AC inverter. • The DC–AC inverter outputs a five-level voltage. • The DC–AC inverter performs the functions of DC–AC power conversion and active power filter. - Abstract: A novel power electronic interface for the grid-connected fuel cell power generation system is proposed in this paper. This power electronic interface is composed of a DC–DC power converter and a DC–AC inverter. A voltage doubler based topology is adopted to configure the DC–DC power converter to perform high step-up gain for boosting the output voltage of the fuel cell to a higher voltage. Moreover, the input current ripple of the fuel cell is suppressed by controlling the DC–DC power converter. The DC–AC inverter is configured by a dual buck power converter and a full-bridge power converter to generate a five-level AC output voltage. The DC–AC inverter can perform the functions of DC–AC power conversion and active power filtration. A 1.2 kW hardware prototype is developed to verify the performance of the proposed power electronic interface for the grid-connected fuel cell power generation system. The experimental results show that the proposed power electronic interface for the grid-connected fuel cell power generation system has the expected performance

  14. Examining hydrogen transitions.

    Plotkin, S. E.; Energy Systems

    2007-03-01

    This report describes the results of an effort to identify key analytic issues associated with modeling a transition to hydrogen as a fuel for light duty vehicles, and using insights gained from this effort to suggest ways to improve ongoing modeling efforts. The study reported on here examined multiple hydrogen scenarios reported in the literature, identified modeling issues associated with those scenario analyses, and examined three DOE-sponsored hydrogen transition models in the context of those modeling issues. The three hydrogen transition models are HyTrans (contractor: Oak Ridge National Laboratory), MARKAL/DOE* (Brookhaven National Laboratory), and NEMS-H2 (OnLocation, Inc). The goals of these models are (1) to help DOE improve its R&D effort by identifying key technology and other roadblocks to a transition and testing its technical program goals to determine whether they are likely to lead to the market success of hydrogen technologies, (2) to evaluate alternative policies to promote a transition, and (3) to estimate the costs and benefits of alternative pathways to hydrogen development.

  15. A French fuel cell prototype

    A French prototype of a fuel cell based on the PEM (proton exchange membrane) technology has been designed by Helion, a branch of Technicatome, this fuel cell delivers 300 kW and will be used in naval applications and terrestrial transport. The main advantages of fuel cell are: 1) no contamination, even if the fuel used is natural gas the quantities of CO2 and CO emitted are respectively 17 and 75 times as little as the maximal quantities allowed by European regulations, 2) efficiency, the electric yield is up to 60 % and can reach 80 % if we include the recovery of heat, 3) silent, the fuel cell itself does not make noise. The present price of fuel cell is the main reason that hampers its industrial development, this price is in fact strongly dependant on the cost of its different components: catalyzers, membranes, bipolar plates and the hydrogen supply. This article gives the technical characteristics of the Helion's fuel cell. (A.C.)

  16. Josephson effects in an alternating current biased transition edge sensor

    Gottardi, Luciano; Akamatsu, Hiroki; van der Kuur, Jan; Bruijn, Marcel P; Hartog, Roland H den; Hijmering, Richard; Khosropanah, Pourya; Lambert, Colin; van der Linden, Anton J; Ridder, Marcel L; Suzuki, Toyo; Gao, Jan R

    2016-01-01

    We report the experimental evidence of the ac Josephson effect in a transition edge sensor (TES) operating in a frequency domain multiplexer and biased by ac voltage at MHz frequencies. The effect is observed by measuring the non-linear impedance of the sensor. The TES is treated as a weakly linked superconducting system and within the resistively shunted junction model framework. We provide a full theoretical explanation of the results by finding the analytic solution of the non-inertial Langevian equation of the system and calculating the non-linear response of the detector to a large ac bias current in the presence of noise.

  17. Magnetic images of the disintegration process of tablets in the human stomach by ac biosusceptometry

    Corá, L. A.; Andreis, U.; Romeiro, F. G.; Américo, M. F.; Oliveira, R. B.; Baffa, O.; Miranda, J. R. A.

    2005-12-01

    Oral administration of solid dosage forms is usually preferred in drug therapy. Conventional imaging methods are essential tools to investigate the in vivo performance of these formulations. The non-invasive technique of ac biosusceptometry has been introduced as an alternative in studies focusing on gastrointestinal motility and, more recently, to evaluate the behaviour of magnetic tablets in vivo. The aim of this work was to employ a multisensor ac biosusceptometer system to obtain magnetic images of disintegration of tablets in vitro and in the human stomach. The results showed that the transition between the magnetic marker and the magnetic tracer characterized the onset of disintegration (t50) and occurred in a short time interval (1.1 ± 0.4 min). The multisensor ac biosusceptometer was reliable to monitor and analyse the in vivo performance of magnetic tablets showing accuracy to quantify disintegration through the magnetic images and to characterize the profile of this process.

  18. Magnetic images of the disintegration process of tablets in the human stomach by ac biosusceptometry

    Oral administration of solid dosage forms is usually preferred in drug therapy. Conventional imaging methods are essential tools to investigate the in vivo performance of these formulations. The non-invasive technique of ac biosusceptometry has been introduced as an alternative in studies focusing on gastrointestinal motility and, more recently, to evaluate the behaviour of magnetic tablets in vivo. The aim of this work was to employ a multisensor ac biosusceptometer system to obtain magnetic images of disintegration of tablets in vitro and in the human stomach. The results showed that the transition between the magnetic marker and the magnetic tracer characterized the onset of disintegration (t50) and occurred in a short time interval (1.1 ± 0.4 min). The multisensor ac biosusceptometer was reliable to monitor and analyse the in vivo performance of magnetic tablets showing accuracy to quantify disintegration through the magnetic images and to characterize the profile of this process

  19. Logarithmic ac response in the heavy-fermion superconductor URu2Si2

    Ac-magnetic-susceptibility χac(T) measurements as a function of frequency f and excitation field hac have been performed on a single crystal of the heavy-fermion superconductor URu2Si2 in magnetic fields H up to 30 kOe applied along the c axis. The apparent superconducting transition temperature Tc shows an unexpected and approximately logarithmic increase (decrease) with f (hac) that is enhanced with H, which suggests the existence of an irreversibility line below the upper critical field Hc2(T) in URu2Si2. Isothermal χac vs H sweeps were used to define Hc2(T) which was independent of f and hac

  20. Noise reduction in AC-coupled amplifiers

    Serrano Finetti, Roberto Ernesto; Pallàs Areny, Ramon

    2014-01-01

    AC-coupled amplifiers are noisier than dc-coupled amplifiers because of the thermal noise of the resistor(s) in the ac-coupling network and the increased contribution of the amplifier input noise current i(n). Both contributions, however, diminish if the corner frequency f(c) of the high-pass filter observed by the signal is lowered, the cost being a longer transient response. At the same time, the presence of large resistors in the ac-coupling network suggests that the use of FET-input ampli...

  1. Today's innovation in the fuel cycle

    This brief article reviews the main recent technical innovations in the fuel cycle. We can quote: -) the enrichment through ultra-centrifugation, -) new transport casks for Mox spent fuels, -) the use of the cold melting pot technology for waste vitrification, or -) the recycling of Pu in EPR cores. An efficient innovation policy relies on 3 axis: first a good understanding of the physics of events and their impact on the fuel cycle, secondly an optimized organization of humane resource in order to get a pool of adequate experts, and thirdly to identify the right technical issues to be studied and coordinate research works. (A.C.)

  2. Structure and Control Strategies of Fuel Cell Vehicle

    宋建国; 张承宁; 孙逢春; 钟秋海

    2004-01-01

    The structure and kinds of the fuel cell vehicle (FCV) and the mathematical model of the fuel cell processor are discussed in detail. FCV includes many parts: the fuel cell thermal and water management, fuel supply, air supply and distribution, AC motor drive, main and auxiliary power management, and overall vehicle control system. So it requires different kinds of control strategies, such as the PID method, zero-pole method, optimal control method, fuzzy control and neural network control. Along with the progress of control method, the fuel cell vehicle's stability and reliability is up-and-up. Experiment results show FCV has high energy efficiency.

  3. Fault Tolerant Three-Phase AC Motor Drive Topologies:A Comparison of Features, Cost, and Limitations

    2005-01-01

    THE RELIABILITY of adjustables peed ac motor drives is an area of great interest for all members of the drives community and marketplace. This is particularly the case for the military, aerospace and automotive industries that are increasingly adopting variable speed drives in order to improve overall system efficiency and performance. There are certain safety critical applications such as steering, fuel pumps,

  4. Nuclear fuels

    Beauvy, M.; Berthoud, G.; Defranceschi, M.; Ducros, G.; Guerin, Y.; Limoge, Y.; Madic, Ch.; Santarini, G.; Seiler, J.M.; Sollogoub, P.; Vernaz, E.; Guillet, J.L.; Ballagny, A.; Bechade, J.L.; Bonin, B.; Brachet, J.Ch.; Delpech, M.; Dubois, S.; Ferry, C.; Freyss, M.; Gilbon, D.; Grouiller, J.P.; Iracane, D.; Lansiart, S.; Lemoine, P.; Lenain, R.; Marsault, Ph.; Michel, B.; Noirot, J.; Parrat, D.; Pelletier, M.; Perrais, Ch.; Phelip, M.; Pillon, S.; Poinssot, Ch.; Vallory, J.; Valot, C.; Pradel, Ph.; Bonin, B.; Bouquin, B.; Dozol, M.; Lecomte, M.; Vallee, A.; Bazile, F.; Parisot, J.F.; Finot, P.; Roberts, J.F

    2009-07-01

    Fuel is one of the essential components in a reactor. It is within that fuel that nuclear reactions take place, i.e. fission of heavy atoms, uranium and plutonium. Fuel is at the core of the reactor, but equally at the core of the nuclear system as a whole. Fuel design and properties influence reactor behavior, performance, and safety. Even though it only accounts for a small part of the cost per kilowatt-hour of power provided by current nuclear power plants, good utilization of fuel is a major economic issue. Major advances have yet to be achieved, to ensure longer in-reactor dwell-time, thus enabling fuel to yield more energy; and improve ruggedness. Aside from economics, and safety, such strategic issues as use of plutonium, conservation of resources, and nuclear waste management have to be addressed, and true technological challenges arise. This Monograph surveys current knowledge regarding in-reactor behavior, operating limits, and avenues for R and D. It also provides illustrations of ongoing research work, setting out a few noteworthy results recently achieved. Content: 1 - Introduction; 2 - Water reactor fuel: What are the features of water reactor fuel? 9 (What is the purpose of a nuclear fuel?, Ceramic fuel, Fuel rods, PWR fuel assemblies, BWR fuel assemblies); Fabrication of water reactor fuels (Fabrication of UO{sub 2} pellets, Fabrication of MOX (mixed uranium-plutonium oxide) pellets, Fabrication of claddings); In-reactor behavior of UO{sub 2} and MOX fuels (Irradiation conditions during nominal operation, Heat generation, and removal, The processes involved at the start of irradiation, Fission gas behavior, Microstructural changes); Water reactor fuel behavior in loss of tightness conditions (Cladding, the first containment barrier, Causes of failure, Consequences of a failure); Microscopic morphology of fuel ceramic and its evolution under irradiation; Migration and localization of fission products in UOX and MOX matrices (The ceramic under

  5. The Effect of the Feedback Controller on Superconducting Tokamak AC Losses + AC-CRPP user manual

    Superconducting coils in a Tokamak are subject to AC losses when the field transverse to the coil current varies. A simple model to evaluate the AC losses has been derived and benchmarked against a complete model used in the ITER design procedure. The influence of the feedback control strategy on the AC losses is examined using this model. An improved controller is proposed, based on this study. (author)

  6. Guiding Principles in Selecting AC To DC Converters For Power Factor Corrections in AC Transmission System

    Ibekwe B.E

    2014-10-01

    Full Text Available The ac to dc converters’ power factors correction in ac transmission system were investigated. The studies include: phase-controlled converter; pulse width modulated (PWM converter and ac input current shaped converter. Using Fourier series, power factors of these converters were calculated and simulated using MATLAB. The resulting curves are displayed in the hard copies for practical guides in the choice of converters; and comparatively, current shaped type is the best.

  7. Energy Transition Initiative: Islands Playbook (Book)

    2015-01-01

    The Island Energy Playbook (the Playbook) provides an action-oriented guide to successfully initiating, planning, and completing a transition to an energy system that primarily relies on local resources to eliminate a dependence on one or two imported fuels. It is intended to serve as a readily available framework that any community can adapt to organize its own energy transition effort.

  8. Alternating parity bands in doubly odd 218Ac129 and octupole instability in the light actinide region

    High-spin states of doubly odd 218Ac129 have been investigated using in-beam α, γ and conversion electron spectroscopy techniques through the 209Bi(12(13)C,3(4)n) fusion-evaporation reactions. The level scheme of 218Ac shows three interconnected, alternating parity structures, each one linked by strong E1 transitions. Two of these bands are strikingly similar to the known scheme of the isotone 217Ra and this analogy is shown to persist for the pair 220Ac, 219Ra. The relation between the structure of 218Ac and its neighbors is thoroughly discussed showing that the first signals of octupole collectivity appear for N = 129. (orig.)

  9. Transition joint

    A transition joint is disclosed for joining together tubular pieces formed respectively from a low alloy or carbon steel and a high temperature alloy composition having substantially different characteristics such as coefficient of thermal expansion, the transition joint including a plurality of tubular parts interconnected with each other by means of friction weld joints formed at an angle of 900 to the axis of the transition joint, the tubular parts at opposite ends of the transition joint being selected to facilitate in situ welding to the low alloy or carbon steel and high temperature alloy respectively. This friction welded transition joint can be used whenever different tubular pieces need to be joined together so that the joint can withstand high temperatures, for instance in heat exchangers and the such like. (Auth.)

  10. Micro pumping methods based on AC electrokinetics and Electrorheologically actuated PDMS valves

    Soni, Gaurav; Squires, Todd; Meinhart, Carl

    2006-11-01

    We have developed 2 different micropumping methods for transporting ionic fluids through microchannels. The first method is based on Induced Charge Electroosmosis (ICEO) and AC flow field-effect. We used an AC electric field to produce a symmetric ICEO flow on a planar electrode, called `gate'. In order to break the symmetry of ICEO, we applied an additional AC voltage to the gate electrode. Such modulation of the gate potential is called field effect and produces a unidirectional pumping over the gate surface. We used micro PIV to measure pumping velocities for a range of ionic concentration, AC frequency and gate voltage. We have also conducted numerical simulations to understand the deteriorating effect of lateral conduction of surface charge on the pumping velocities. The second method is based on vibration of a flexible PDMS diaphragm actuated by an electrorheological (ER) fluid. ER fluid is a colloidal suspension exhibiting a reversible liquid-to-solid transition under an electric field. This liquid-to-solid transition can yield very high shear stress and can be used to open and close a PDMS valve. Three such valves were fabricated and actuated in a peristaltic fashion in order to achieve positive displacement pumping of fluids.

  11. A Simple Load Power Estimator For Quasi-Direct AC-AC Converter System

    Marian GAICEANU; Emil ROSU

    2003-01-01

    In this paper a simple load power estimator for the three-phase quasi-direct acac converter system is reported. Since the ac-ac converter control by means of pulsewidth modulation (PWM) is based on the power balance concept, its load power should be known. Two control boards, based on the dSMC (digital Smart Motion Controller) 30 MIPS 32-bit fixed-point digital signal processor (DSP), were involved in the ac-ac system driving. By using the power balance control, the DC link voltage variation ...

  12. Dynamic Stark effect and forbidden-transition spectrallineshapes

    Stalnaker, Jason E.; Budker, D.; Freedman, S.J.; Guzman, J.S.; Rochester, S.M.; Yashchuk, V.V.

    2005-12-15

    We report on an experimental and theoretical study of thedynamic (ac) Stark effect on a for bidden transition. A general frameworkfor parameterizing and describing off-resonant ac-Stark shifts ispresented. A model is developed to calculate spectral line shapesresulting from resonant excitation of atoms in an intense standinglight-wave in the presence of off-resonant ac-Stark shifts. The model isused in the analysis and interpretation of a measurement of the ac-Starkshifts of the static-electric-field-induced 6s2 1S0 -->5d6s 3D1transition at 408 nm in atomic Yb. The results are in agreement withestimates of the ac-Stark shift of the transition under the assumptionthat the shift is dominated by that of the 6s2 1S0 ground state. Adetailed description of the experiment and analysis is presented. Abi-product of this work is an ind ependent determination (from thesaturation behavior of the 408-nm transition) of the Stark transitionpolarizability, which is found to be in agreement with our earliermeasurement. This work is part of the ongoing effort aimed at a precisionmeasurement of atomic parity-violation effects in Yb.

  13. Consistent behaviour of AC susceptibility and transport properties in magnetic superconductor RuSr{sub 2}GdCu{sub 2}O{sub 8}

    Ocko, M. E-mail: ocko@ifs.hr; Zivkovic, I.; Prester, M.; Drobac, Dj.; Ariosa, D.; Berger, H.; Pavuna, D

    2004-02-01

    We report on AC susceptibility, resistivity, thermopower and measurements of sintered magnetic superconductor RuSr{sub 2}GdCu{sub 2}O{sub 8}. The antiferromagnetic phase transition at 133 K is seen clearly in the AC susceptibility as well as in the derivative of resistivity and thermopower. Above the antiferromagnetic transition, we have found some new evidences of the similarity between HTC compounds and the magnetic superconductor. The onset of superconductivity is observed by both transport methods at 46 K, and an explanation why it is not seen in the AC susceptibility data is given. The end of the SC transition occurs at about 24 K in all measured properties. We discuss the steps of broad SC transition, especially the maximum in susceptibility at 34 K, and compare our results with related studies reported in the literature.

  14. Consistent behaviour of AC susceptibility and transport properties in magnetic superconductor RuSr 2GdCu 2O 8

    Očko, M.; Živkovic, I.; Prester, M.; Drobac, Dj.; Ariosa, D.; Berger, H.; Pavuna, D.

    2004-02-01

    We report on AC susceptibility, resistivity, thermopower and measurements of sintered magnetic superconductor RuSr 2GdCu 2O 8. The antiferromagnetic phase transition at 133 K is seen clearly in the AC susceptibility as well as in the derivative of resistivity and thermopower. Above the antiferromagnetic transition, we have found some new evidences of the similarity between HTC compounds and the magnetic superconductor. The onset of superconductivity is observed by both transport methods at 46 K, and an explanation why it is not seen in the AC susceptibility data is given. The end of the SC transition occurs at about 24 K in all measured properties. We discuss the steps of broad SC transition, especially the maximum in susceptibility at 34 K, and compare our results with related studies reported in the literature.

  15. Transport AC losses in YBCO coated conductors

    Majoros, M [Ohio State University, Columbus, OH 43210 (United States); Ye, L [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Velichko, A V [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Coombs, T A [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Sumption, M D [Ohio State University, Columbus, OH 43210 (United States); Collings, E W [Ohio State University, Columbus, OH 43210 (United States)

    2007-09-15

    Transport AC loss measurements have been made on YBCO-coated conductors prepared on two different substrate templates-RABiTS (rolling-assisted biaxially textured substrate) and IBAD (ion-beam-assisted deposition). RABiTS samples show higher losses compared with the theoretical values obtained from the critical state model, with constant critical current density, at currents lower than the critical current. An origin of this extra AC loss was demonstrated experimentally by comparison of the AC loss of two samples with different I-V curves. Despite a difference in I-V curves and in the critical currents, their measured losses, as well as the normalized losses, were practically the same. However, the functional dependence of the losses was affected by the ferromagnetic substrate. An influence of the presence of a ferromagnetic substrate on transport AC losses in YBCO film was calculated numerically by the finite element method. The presence of a ferromagnetic substrate increases transport AC losses in YBCO films depending on its relative magnetic permeability. The two loss contributions-transport AC loss in YBCO films and ferromagnetic loss in the substrate-cannot be considered as mutually independent.

  16. AcEST: DK948877 [AcEST

    Full Text Available .. 37 0.13 sp|Q3ZBT1|TERA_BOVIN Transitional endoplasmic reticulum ATPase O... 37 0.13 sp|Q07844|RIX7_YEAST Ribosome biog... 0.70 tr|Q9W4W8|Q9W4W8_DROME CG2658, isoform A OS=Drosophila melanogas... 38 0.70 tr|Q8MT03|Q8MT03_DROME CG2...658, isoform B OS=Drosophila melanogas... 38 0.70 tr|Q5CRP4|Q5CRP4_CRYPV Nuclear VCP like protein with 2 AAA ATpas..., Zheng Zhang, Webb Miller, and David J. Lipman (1997), Gapped BLAST and PSI-BLAST: a new generation of protein database search prog...it OS=Pyrob... 36 0.17 sp|Q67WJ2|FTSH6_ORYSJ Cell division protease ftsH homolog

  17. AcEST: BP917101 [AcEST

    Full Text Available sis cinerea ... 34 4.7 tr|Q7NTE5|Q7NTE5_CHRVO Type-4 fimbrial biogenesis PilV transmemb... 34 4.8 tr|Q062K5|...L+ Sbjct: 664 QIYLVFAFWQWLRGDSW-VPDMLAAILLVIYLV 695 >tr|A6UDY7|A6UDY7_SINMW ABC transporter related OS=Sinorhizobium medicae (stra...T Sbjct: 787 PTELVSSPPMEPPSSSFSLLSQPSSASLE---ENEGGDAMTTDTTVPPASTAPPT 838 >tr|Q7NTE5|Q7NTE5_CHRVO Type-4 fimbrial biogenesis PilV tran...cterized protein OS=Ustil... 36 1.3 tr|A6UDY7|A6UDY7_SINMW ABC transporter related...6.6 sp|P11101|STP2_RAT Nuclear transition protein 2 OS=Rattus norveg... 30 8.5 sp|P08855|ICAL_RABIT Calpasta

  18. Fuel cycles

    AECL publications, from the open literature, on fuels and fuel cycles used in CANDU reactors are listed in this bibliography. The accompanying index is by subject. The bibliography will be brought up to date periodically

  19. The AC Stark, Stern-Gerlach, and Quantum Zeno Effects in Interferometric Qubit Readout

    Sidles, J A

    1996-01-01

    This article describes the AC Stark, Stern-Gerlach, and Quantum Zeno effects as they are manifested during continuous interferometric measurement of a two-state quantum system (qubit). A simple yet realistic model of the interferometric measurement process is presented, and solved to all orders of perturbation theory in the absence of thermal noise. The statistical properties of the interferometric Stern-Gerlach effect are described in terms of a Fokker-Plank equation, and a closed-form expression for the Green's function of this equation is obtained. Thermal noise is added in the form of a externally-applied Langevin force, and the combined effects of thermal noise and measurement are considered. Optical Bloch equations are obtained which describe the AC Stark and Quantum Zeno effects. Spontaneous qubit transitions are shown to be observationally equivalent to transitions induced by external Langevin forces. The effects of delayed choice are discussed. Practical experiments involving trapped ions are suggest...

  20. Wetting transitions

    When a liquid droplet is put onto a surface, two situations distinguishable by the contact angle may result. If the contact angle is zero, the droplet spreads across the surface, a situation referred to as complete wetting. On the other hand, if the contact angle is between 0 deg. and 180 deg., the droplet does not spread, a situation called partial wetting. A wetting transition is a surface phase transition from partial wetting to complete wetting. We review the key experimental findings on this transition, together with simple theoretical models that account for the experiments. The wetting transition is generally first order (discontinuous), implying a discontinuity in the first derivative of the surface free energy. In this case, if one measures the thickness of the adsorbed film beside the droplet, at the wetting transition a discontinuous jump in film thickness occurs from a microscopically thin to a thick film. We show that this can lead to the observation of metastable surface states and an accompanying hysteresis. The observed hysteresis poses, in turn, a number of questions concerning the nucleation of wetting films that we also consider here. In addition, we consider the equilibrium wetting film thickness that results from a competition between the long-range van der Waals forces and gravity. Finally, the first-order character of the wetting transition can lead to a similar transition even when the phase that does the wetting is not (yet) stable in the bulk. For such prewetting transitions, a discontinuous thin-to-thick film transition occurs off bulk coexistence. We show that, for the large variety of systems for which prewetting transitions have been observed, the behaviour is surprisingly uniform, and can be mapped onto a simple generic phase diagram. The second part of the review deals with the exceptions to the first-order nature of the wetting transition. Two different types of continuous or critical wetting transition have been reported, for which

  1. Fossil Fuels.

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with fossil fuels. Some topics covered are historic facts, development of fuels, history of oil production, current and future trends of the oil industry, refining fossil fuels, and environmental problems. Material in each unit may…

  2. Phase transitions

    Solé, Ricard V

    2011-01-01

    Phase transitions--changes between different states of organization in a complex system--have long helped to explain physics concepts, such as why water freezes into a solid or boils to become a gas. How might phase transitions shed light on important problems in biological and ecological complex systems? Exploring the origins and implications of sudden changes in nature and society, Phase Transitions examines different dynamical behaviors in a broad range of complex systems. Using a compelling set of examples, from gene networks and ant colonies to human language and the degradation o

  3. AC impedance studies of V2O5 containing glasses

    Glasses with composition V2O5-BaO-MO-B2O3(MO=SiO2,GeO2,P2O5) were studied using AC impedance analyzer. The measurements show that conductivities increase with V2O5 contents, and the P2O5 containing glasses have higher conductivities. The electric modulus was analyzed based on the Kohlrausch-Williams-Watts (KWW) relaxation function, φ(t)=exp[-(t/τ0)1-n]. The exponent n increases with V2O5 content. In addition, as the temperature approaches glass transition temperature, n increases with temperature. The results are interpreted in terms of Ngai's coupling model when applied to polaron conductivity relaxation

  4. Delocalization of Phase Perturbations and the Stability of AC Electricity Grids

    Kettemann, S.

    2015-01-01

    The energy transition towards an increased supply of renewable energy raises concerns that existing electricity grids, built to connect few centralized large power plants with consumers, may become more difficult to control and stabilized with a rising number of decentralized small scale generators. Here, we aim to study therefore, how local phase perturbations which may be caused by local power fluctuations, affect the AC grid stability. To this end, we start from nonlinear power balance equ...

  5. Fuel choices for fuel-cell vehicles : well-to-wheel energy and emission impacts

    Because of their high energy efficiencies and low emissions, fuel-cell vehicles (FCVs) are undergoing extensive research and development. While hydrogen will likely be the ultimate fuel to power fuel-cell vehicles, because of current infrastructure constraints, hydrogen-carrying fuels are being investigated as transitional fuel-cell fuels. A complete well-to-wheels (WTW) evaluation of fuel-cell vehicle energy and emission effects that examines (1) energy feedstock recovery and transportation; (2) fuel production, transportation, and distribution; and (3) vehicle operation must be conducted to assist decision makers in selecting the fuel-cell fuels that achieve the greatest energy and emission benefits. A fuel-cycle model developed at Argonne National Laboratory--called the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model--was used to evaluate well-to-wheels energy and emission impacts of various fuel-cell fuels. The results show that different fuel-cell fuels can have significantly different energy and greenhouse gas emission effects. Therefore, if fuel-cell vehicles are to achieve the envisioned energy and emission reduction benefits, pathways for producing the fuels that power them must be carefully examined.

  6. Economic aspects of Dukovany NPP fuel cycle

    The paper discusses some aspects of high burnup program implementation at Dukovany NPP and its influence on the fuel cycle costs. Dukovany internal fuel cycle is originally designed as a three years cycle of the Out-In-In fuel reloading patterns. These reloads are not only uneconomical but they additionally increased the radiation load of the reactor pressure vessel due to high neutron leakage typical for Out-In-In loading pattern. To avoid the high neutron leakage from the core a transition to 4-year fuel cycle is started in 1987. The neutron leakage from the core is sequentially decreased by insertion of older fuel assemblies at the core periphery. Other developments in fuel cycle are: 1) increasing of enrichment in control assemblies (3.6% of U-235); 2) improvement in fuel assembly design (reduce the assembly shroud thickness from 2.1 to 1.6 mm); 3) introduction of Zr spacer grid instead of stainless steel; 4) introduction of new type of assembly with profiled enrichment with average value of 3.82%. Due to increased reactivity of the new assemblies the transition to the partial 5-year fuel cycle is required. Typical fuel loading pattern for 3, 3.5, 4 and 5-year cycles are shown in the presented paper. An evaluation of fuel cost is also discussed by using comparative analysis of different fuel cycle options. The analysis shows that introduction of the high burnup program has decrease relative fuel cycle costs

  7. The Sloan Lens ACS Survey. V. The full ACS strong-lens sample

    Bolton, Adam S.; Burles, Scott; Koopmans, Leon V. E.; Treu, Tommaso; Gavazzi, Raphael; Moustakas, Leonidas A.; Wayth, Randall; Schlegel, David J.

    2008-01-01

    We present the definitive data for the full sample of 131 strong gravitational lens candidates observed with the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope by the Sloan Lens ACS (SLACS) Survey. All targets were selected for higher redshift emission lines and lower redshift c

  8. Irradiated fuel transport emergency arrangements

    For over 30 years spent nuclear fuel has been transported by road and rail. In that time, there has never been an accident involving the release of radioactivity. Notwithstanding this excellent record it is both necessary and desirable to have contingency plans for any emergency situation. The Irradiated Fuel Transport Flask Emergency Plan for England and Wales (IFTFEP) has been developed and administered by Nuclear Electric plc to set out the detailed response by the nuclear industry to a mishap involving an irradiated fuel flask in transit. (author)

  9. Fuel distribution

    Tison, R.R.; Baker, N.R.; Blazek, C.F.

    1979-07-01

    Distribution of fuel is considered from a supply point to the secondary conversion sites and ultimate end users. All distribution is intracity with the maximum distance between the supply point and end-use site generally considered to be 15 mi. The fuels discussed are: coal or coal-like solids, methanol, No. 2 fuel oil, No. 6 fuel oil, high-Btu gas, medium-Btu gas, and low-Btu gas. Although the fuel state, i.e., gas, liquid, etc., can have a major impact on the distribution system, the source of these fuels (e.g., naturally-occurring or coal-derived) does not. Single-source, single-termination point and single-source, multi-termination point systems for liquid, gaseous, and solid fuel distribution are considered. Transport modes and the fuels associated with each mode are: by truck - coal, methanol, No. 2 fuel oil, and No. 6 fuel oil; and by pipeline - coal, methane, No. 2 fuel oil, No. 6 oil, high-Btu gas, medium-Btu gas, and low-Btu gas. Data provided for each distribution system include component makeup and initial costs.

  10. Fuel assembly

    A fuel assembly is composed of a fuel bundle surrounded by a channel box. The fuel bundle comprises a large number of fuel rods and a water rod secured to upper and lower tie plate by way of a plurality of fuel spacers. Grooves (libretti) are formed in the direction along the flowing direction of coolants to at least one of the surface of the fuel rods, the inner surface of the channel box, the surface of the water rod and spacer constituting components. In this case, the lateral width of the libretto in the flowing direction is determined as the minimum thickness of the bottom layer of a layered flow determined by a coolant flow rate. With such a constitution, abrasion resistance relative to coolants is reduced to reduce the pressure loss of fuel assemblies. (I.N.)

  11. AC losses in filamentary YBCO/hastelloy

    Full text: The AC hysteresis loss of a long YBCO thin-film superconducting strip in a perpendicular AC magnetic field can be reduced by subdividing the film into narrow parallel strips (filaments). The hysteresis loss depends on the film critical current density Jc, the film thickness d, the filament width 2a and the lateral spacing L between filaments as well as on the AC magnetic field amplitude Hm. In addition, if the film is deposited onto a YSZ/hastelloy substrate to form a flexible tape, eddy current loss occurs in the hastelloy metal. The eddy current loss depends on the resistivity p of the hastelloy, the width 2w and thickness dm of the hastelloy substrate as well as on the frequency f and amplitude Hm. We have calculated the hysteresis and eddy current losses as a function of Jc, d, 2a, L, p, w, dm, f, and Hm to find optimal design parameters for a YBCO/hastelloy tape. As the AC loss is related to the loss component X'' of the AC susceptibility, we have measured X'' at different frequencies f and amplitudes Hm for several filamentary designs of YBCO/hastelloy tapes and compared our experimental results with our model calculations

  12. VISION: Verifiable Fuel Cycle Simulation Model

    Jacob J. Jacobson; Abdellatif M. Yacout; Gretchen E. Matthern; Steven J. Piet; David E. Shropshire

    2009-04-01

    The nuclear fuel cycle is a very complex system that includes considerable dynamic complexity as well as detail complexity. In the nuclear power realm, there are experts and considerable research and development in nuclear fuel development, separations technology, reactor physics and waste management. What is lacking is an overall understanding of the entire nuclear fuel cycle and how the deployment of new fuel cycle technologies affects the overall performance of the fuel cycle. The Advanced Fuel Cycle Initiative’s systems analysis group is developing a dynamic simulation model, VISION, to capture the relationships, timing and delays in and among the fuel cycle components to help develop an understanding of how the overall fuel cycle works and can transition as technologies are changed. This paper is an overview of the philosophy and development strategy behind VISION. The paper includes some descriptions of the model and some examples of how to use VISION.

  13. TMI Fuel Characteristics for Disposal Criticality Analysis

    Larry L. Taylor

    2003-09-01

    This report documents the reported contents of the Three Mile Island Unit 2 (TMI-2) canisters. proposed packaging, and degradation scenarios expected in the repository. Most fuels within the U.S. Department of Energy spent nuclear fuel inventory deal with highly enriched uranium, that in most cases require some form of neutronic poisoning inside the fuel canister. The TMI-2 fuel represents a departure from these fuel forms due to its lower enrichment (2.96% max.) values and the disrupted nature of the fuel itself. Criticality analysis of these fuel canisters has been performed over the years to reflect conditions expected during transit from the reactor to the Idaho National Engineering and Environmental Laboratory, water pool storage,1 and transport/dry-pack storage at Idaho Nuclear Technology and Engineering Center.2,3 None of these prior analyses reflect the potential disposal conditions for this fuel inside a postclosure repository.

  14. AC susceptibility of Sr2RuO4-Sr3Ru2O7 eutectics: Dependence on AC field strength and frequency

    The low-field AC susceptibility of a eutectic crystal of the Sr2RuO4-Sr3Ru2O7 system exhibits superconducting transition features at three temperatures. We investigate the dependence on AC field strength from 0.021 to 2.1 Oe-rms and frequency from 17 to 3 kHz. The two lower-temperature peaks in the imaginary part originate in the Sr3Ru2O7 part. The lowest-temperature peak is exceedingly sensitive to the field amplitude and shifts to lower temperatures with increasing amplitude. By contrast, it slightly shifts to higher temperatures with increasing frequency. These results support that the sensitive features involve weak links forming the screening paths

  15. AC loss performance of CS insert coil

    The ITER Central Solenoid (CS) model coil and the CS insert coil were fabricated, and the test was carried out. The AC loss measurement of the coil is one of the most important tests to determine coil performance. The AC loss of a short sample conductor for the CS insert coil was measured by using the calorimetric method, and the coupling time constants of the conductor were estimated to be 30 ms and 20 ms for pulse and discharge tests, respectively. The AC loss of the CS insert coil was measured by using the calorimetric method for pulse and discharge tests. The coupling time constant estimated from the result of the pulse tests was 34 ms and almost equal to that of the short sample. The coupling time constant for the discharge test was estimated to be 140 ms and about 4 times that of the pulse test. (author)

  16. ac propulsion system for an electric vehicle

    Geppert, S.

    1980-01-01

    It is pointed out that dc drives will be the logical choice for current production electric vehicles (EV). However, by the mid-80's, there is a good chance that the price and reliability of suitable high-power semiconductors will allow for a competitive ac system. The driving force behind the ac approach is the induction motor, which has specific advantages relative to a dc shunt or series traction motor. These advantages would be an important factor in the case of a vehicle for which low maintenance characteristics are of primary importance. A description of an EV ac propulsion system is provided, taking into account the logic controller, the inverter, the motor, and a two-speed transmission-differential-axle assembly. The main barrier to the employment of the considered propulsion system in EV is not any technical problem, but inverter transistor cost.

  17. Transition? What transition? : Changing energy systems in an increasingly carbon constrained world

    Mc Cahery, J.A.; Lopez de Silanes, Florencio; de Roode, Alexander

    2014-01-01

    Energy transitions have been taking place continuously since the Industrial Revolution. These transitions primarily involve national energy mixes. In general, countries keep moving up the energy ladder, meaning that they integrate larger and larger proportions of specialized fuels into their energy

  18. AC loss in superconducting tapes and cables

    Oomen, Marijn Pieter

    High-temperature superconductors are developed for use in power-transmission cables, transformers and motors. The alternating magnetic field in these devices causes AC loss, which is a critical factor in the design. The study focuses on multi-filament Bi-2223/Ag tapes exposed to a 50-Hz magnetic field at 77 K. The AC loss is measured with magnetic, electric and calorimetric methods. The results are compared to theoretical predictions based mainly on the Critical-State Model. The loss in high- temperature superconductors is affected by their characteristic properties: increased flux creep, high aspect ratio and inhomogeneties. Filament intergrowths and a low matrix resistivity cause a high coupling-current loss especially when the filaments are fully coupled. When the wide side of the tape is parallel to the external magnetic field, the filaments are decoupled by twisting. In a perpendicular field the filaments can be decoupled only by combining a short twist pitch with a transverse resistivity much higher than that of silver. The arrangement of the inner filaments determines the transverse resistivity. Ceramic barriers around the filaments cause partial decoupling in perpendicular magnetic fields at power frequencies. The resultant decrease in AC loss is greater than the accompanying decrease in critical current. With direct transport current in alternating magnetic field, the transport-current loss is well described with a new model for the dynamic resistance. The Critical- State Model describes well the magnetisation and total AC loss in parallel magnetic fields, at transport currents up to 0.7 times the critical current. When tapes are stacked face-to-face in a winding, the AC-loss density in perpendicular fields is greatly decreased due to the mutual shielding of the tapes. Coupling currents between the tapes in a cable cause an extra AC loss, which is reduced by a careful cable design. The total AC loss in complex devices with many tapes is generally well

  19. ACS air bearing test-bed design

    Glitt, Sascha

    2010-01-01

    This thesis is about the construction and design of a new air bearing test-bed to verify the programmed ACS attitude control algorithm and to validate the ACS MATLAB/SimuLink¬ model of NPSAT1, the second small satellite currently under development at the Naval Postgraduate School Space Systems Academic Group. The software was already verified and validated using a comparable air bearing test-bed. But due to changes in hardware from commercial magnetic torque rods to custom, NPS-built, magneti...

  20. The Effective AC Response of Nonlinear Composites

    WEI En-Bo; GU Guo-Qing

    2001-01-01

    A perturbative approach is used to study the AC response of nonlinear composite media, which obey a current-field relation of the form J = σ E + χ|E|2 E with components having nonlinear response at finite frequencies. For a sinusoidal applied field, we extend the local potential in terms of sinusoidal components at fundamental frequency and high-order harmonic frequencies to treat the nonlinear composites. For nonlinear composite media vith a low concentrations of spherical inclusions, we give the formulae of the nonlinear effective AC susceptibility χ*3ω at the third harmonic frequency.

  1. Modelling and control of hybrid renewable energy system connected to AC grid

    Sami Younsi

    2011-12-01

    Full Text Available This paper discusses the development of new control and supervision method for the optimum operation of hybrid renewable energy system (HRES connected to AC grid. The hybrid system consists of wind generator (WG, diesel generator (DG, and flywheel energy storage system (FESS. These subsystems are based on permanent magnet synchronous machines (PMSM which are controlled by sliding mode control. A supervisor control is designed to determine the energy transfer type of flywheel energy storage system (charging / discharging / no transfer energy, to take decision on diesel generators ON/OFF status, and to determine the reference powers for these two subsystems. The supervisor inputs are the power requested by AC grid, the power generated by wind generator, and the energy stored in flywheel. The objectives of the control and supervision for hybrid renewable energy system are to satisfy the power requested by AC grid, to manage the energy transfer between hybrid system and AC grid, to optimize the use of wind energy, and to reduce fuel of diesel generator. The system is simulated with Matlab – Simulink software and it gave good results.

  2. YBCO thin films in ac and dc films

    Shahzada, S

    2001-01-01

    We report studies on the dc magnetization of YBCO thin films in simultaneously applied dc and ac fields. The effect of the ac fields is to decrease the irreversible magnetization drastically leading to complete collapse of the hysteresis loops for relatively small ac fields (250e). The magnitude of the decrease depends on the component of the ac field parallel to the c-axis. The decrease is non-linear with ac amplitude and is explained in the framework of the critical state response of ultra thin films in perpendicular geometry. The ac fields increase the relaxation rapidly at short times while the long time response appears unaffected. (author)

  3. SINGLE PHASE HIGH FREQUENCY AC CONVERTER FOR INDUCTION HEATING APPLICATION

    M.A INAYATHULLAAH,

    2010-12-01

    Full Text Available The proposed topology reduces the total harmonic distortion (THD of a high frequency AC/AC Converter well below the acceptable limit. This paper deals with a novel single phase AC/DC/AC soft switching utility frequency AC to high frequency AC converter. In this paper a single phase full bridge inverter with Vienna rectifier as front end is used instead of conventional diode bridge rectifier to provide continuous sinusoidal input current with nearly unity power factor at the source side with extremely low distortion.. This power converter is more suitable and acceptable for cost effective high frequency (HF consumer induction heating applications.

  4. AcsA-AcsB: The core of the cellulose synthase complex from Gluconacetobacter hansenii ATCC23769.

    McManus, John B; Deng, Ying; Nagachar, Nivedita; Kao, Teh-hui; Tien, Ming

    2016-01-01

    The gram-negative bacterium, Gluconacetobacter hansenii, produces cellulose of exceptionally high crystallinity in comparison to the cellulose of higher plants. This bacterial cellulose is synthesized and extruded into the extracellular medium by the cellulose synthase complex (CSC). The catalytic component of this complex is encoded by the gene AcsAB. However, several other genes are known to encode proteins critical to cellulose synthesis and are likely components of the bacterial CSC. We have purified an active heterodimer AcsA-AcsB from G. hansenii ATCC23769 to homogeneity by two different methods. With the purified protein, we have determined how it is post-translationally processed, forming the active heterodimer AcsA-AcsB. Additionally, we have performed steady-state kinetic studies on the AcsA-AcsB complex. Finally through mutagenesis studies, we have explored the roles of the postulated CSC proteins AcsC, AcsD, and CcpAx. PMID:26672449

  5. Use of Pyrolyzed Iron Ethylenediaminetetraacetic Acid Modified Activated Carbon as Air–Cathode Catalyst in Microbial Fuel Cells

    Xia, Xue

    2013-08-28

    Activated carbon (AC) is a cost-effective catalyst for the oxygen reduction reaction (ORR) in air-cathode microbial fuel cells (MFCs). To enhance the catalytic activity of AC cathodes, AC powders were pyrolyzed with iron ethylenediaminetetraacetic acid (FeEDTA) at a weight ratio of FeEDTA:AC = 0.2:1. MFCs with FeEDTA modified AC cathodes and a stainless steel mesh current collector produced a maximum power density of 1580 ± 80 mW/m2, which was 10% higher than that of plain AC cathodes (1440 ± 60 mW/m 2) and comparable to Pt cathodes (1550 ± 10 mW/m2). Further increases in the ratio of FeEDTA:AC resulted in a decrease in performance. The durability of AC-based cathodes was much better than Pt-catalyzed cathodes. After 4.5 months of operation, the maximum power density of Pt cathode MFCs was 50% lower than MFCs with the AC cathodes. Pyridinic nitrogen, quaternary nitrogen and iron species likely contributed to the increased activity of FeEDTA modified AC. These results show that pyrolyzing AC with FeEDTA is a cost-effective and durable way to increase the catalytic activity of AC. © 2013 American Chemical Society.

  6. Fuel cycle

    The situation of the nuclear fuel cycle for LWR type reactors in France and in the Federal Republic of Germany was presented in 14 lectures with the aim to compare the state-of-the-art in both countries. In addition to the momentarily changing fuilds of fuel element development and fueling strategies, the situation of reprocessing, made interesting by some recent developmnts, was portrayed and differences in ultimate waste disposal elucidated. (orig.)

  7. Fuel Cells

    Smith, Anders; Pedersen, Allan Schrøder

    2014-01-01

    Fuel cells have been the subject of intense research and development efforts for the past decades. Even so, the technology has not had its commercial breakthrough yet. This entry gives an overview of the technological challenges and status of fuel cells and discusses the most promising applications...... of the different types of fuel cells. Finally, their role in a future energy supply with a large share of fluctuating sustainable power sources, e.g., solar or wind, is surveyed....

  8. Candu fuel and fuel cycles

    A primary rationale for Indonesia to proceed with a nuclear power program is to diversity its energy sources and achieve freedom from future resource constraints. While other considerations, such as economy of power supply, hedging against potential future increases in the price of fossil fuels, fostering the technological development of the Indonesia economy and minimizing greenhouse and other gaseous emissions are important, the strategic resource issue is key. In considering candidate nuclear power technologies upon which to base such a program, a major consideration will be the potential for those technologies to be economically sustained in the face of large future increases in demand for nuclear fuels. The technology or technologies selected should be amenable to evaluation in a rapidly changing technical, economic, resource and environmental policy. The world's proven uranium resources which can be economically recovered represent a fairly modest energy resource if utilization is based on the currently commercialized fuel cycles, even with the use of recovered plutonium in mixed oxide fuels. In the long term, fuel cycles relying solely on the use of light water reactors will encounter increasing fuel supply constraints. Because of its outstanding neutron economy and the flexibility of on-power refueling, CANDU reactors are the most fuel resource efficient commercial reactors and offer the potential for accommodating an almost unlimited variety of advanced and even more fuel efficient cycles. Most of these cycles utilize nuclear fuels which are too low grade to be used in light water reactors, including many products now considered to be waste, such as spent light water reactor fuel and reprocessing products such as recovered uranium. The fuel-cycle flexibility of the CANDU reactor provides a ready path to sustainable energy development in both the short and the long terms. Most of the potential CANDU fuel cycle developments can be accommodated in existing

  9. Nuclear fuel

    All stages of nuclear fuel cycle are analysed with respect to the present situation and future perspectives of supply and demand of services; the prices and the unitary cost estimation of these stages for the international fuel market are also mentioned. From the world resources and projections of uranium consumption, medium-and long term analyses are made of fuel availability for several strategies of use of different reactor types. Finally, the cost of nuclear fuel in the generation of electric energy is calculated to be used in the energetic planning of the electric sector. (M.A.)

  10. Fuel assembly

    Fuel rods enriched with plutonium and fuel rods formed by incorporating combustible poisons in enriched uranium are arranged in square lattice like structure. MOX fuel pellets comprise PuO2 as a fuel material and contain 239Pu, 241Pu as fission products. The gadolinia-incorporated uranium fuel pellets comprise UO2 as a fuel material and gadolinia as a burnable poison incorporated therein and contains 235U as a fuel material. The axial distribution of the concentration of gadolinia contained in the uranium fuel rods is axially divided into three regions in a region less than 1/2 of a fuel effective length, and the concentration of gadolinia is highest at the lowest region, and the concentration of gadolinia is made lower toward the upper regions. With such a constitution, the degree of downward distortion of the axial power distribution is suppressed in a reactor core of a BWR type reactor having a large MOX loading rate. (I.N.)

  11. Fuel assembly

    Izutsu, Sadayuki; Fujita, Satoshi [Hitachi Engineering Co. Ltd., Ibaraki (Japan); Fujimaki, Shingo; Sasagawa, Masaru; Kaneto, Kunikazu; Mochida, Takaaki; Aoyama, Motoo; Shimada, Hidemitsu

    1997-09-09

    Fuel rods enriched with plutonium and fuel rods formed by incorporating combustible poisons in enriched uranium are arranged in square lattice like structure. MOX fuel pellets comprise PuO{sub 2} as a fuel material and contain {sup 239}Pu, {sup 241}Pu as fission products. The gadolinia-incorporated uranium fuel pellets comprise UO{sub 2} as a fuel material and gadolinia as a burnable poison incorporated therein and contains {sup 235}U as a fuel material. The axial distribution of the concentration of gadolinia contained in the uranium fuel rods is axially divided into three regions in a region less than 1/2 of a fuel effective length, and the concentration of gadolinia is highest at the lowest region, and the concentration of gadolinia is made lower toward the upper regions. With such a constitution, the degree of downward distortion of the axial power distribution is suppressed in a reactor core of a BWR type reactor having a large MOX loading rate. (I.N.)

  12. Transitional Shelter

    Shiozaki, Yoshimitsu; TANAKA, Yasuo; Hokugo, Akihiko; Bettencourt, Sofia

    2013-01-01

    Transitional shelter can play a crucial role in housing reconstruction following a mega disaster. Reconstruction of permanent housing cannot move forward until a number of complex issues are settled, such as relocation planning and removal of debris. Even after plans are agreed on and reconstruction begins, it may take several years for permanent housing to be completed. In this context, a...

  13. Ac Stark splitting in multiphoton excitation of atomic hydrogen in flames: Abnormal peak asymmetry due to pressure broadening

    A theory of ac Stark (or Autler-Townes) splitting occurring in double optical resonances, one of which is a two-photon transition is developed. Both laser bandwidth and collisional broadening effects are included. Theoretical results are in excellent agreement with Goldsmith's observation of two-peaked structures in the multiphoton excitation spectra of atomic hydrogen in atmospheric-pressure flames. This is believed to be the first study demonstrating that the peak asymmetry in an ac Stark doublet can be reversed due to pressure broadening

  14. Performance of Halbach magnetized brushless AC motors

    Zhu, Z.Q.; Xia, Z.P.; Shi, Y.F.; Howe, D.; Pride, A.; X. J. Chen

    2003-01-01

    The steady-state performance of Halbach magnetized brushless ac machines when operated in constant torque and flux-weakening modes is investigated both theoretically and experimentally, with particular emphasis on the influence of cross-coupling magnetic saturation on the torque capability.

  15. Ac-dc converter firing error detection

    Each of the twelve Booster Main Magnet Power Supply modules consist of two three-phase, full-wave rectifier bridges in series to provide a 560 VDC maximum output. The harmonic contents of the twelve-pulse ac-dc converter output are multiples of the 60 Hz ac power input, with a predominant 720 Hz signal greater than 14 dB in magnitude above the closest harmonic components at maximum output. The 720 Hz harmonic is typically greater than 20 dB below the 500 VDC output signal under normal operation. Extracting specific harmonics from the rectifier output signal of a 6, 12, or 24 pulse ac-dc converter allows the detection of SCR firing angle errors or complete misfires. A bandpass filter provides the input signal to a frequency-to-voltage converter. Comparing the output of the frequency-to-voltage converter to a reference voltage level provides an indication of the magnitude of the harmonics in the ac-dc converter output signal

  16. AC loss in superconducting tapes and cables

    Oomen, Marijn Pieter

    2000-01-01

    The present study discusses the AC loss in high-temperature superconductors. Superconducting materials with a relatively high critical temperature were discovered in 1986. They are presently developed for use in large-scale power-engineering devices such as power-transmission cables, transformers an

  17. A novel wireless power and data transmission AC to DC converter for an implantable device.

    Liu, Jhao-Yan; Tang, Kea-Tiong

    2013-01-01

    This article presents a novel AC to DC converter implemented by standard CMOS technology, applied for wireless power transmission. This circuit combines the functions of the rectifier and DC to DC converter, rather than using the rectifier to convert AC to DC and then supplying the required voltage with regulator as in the transitional method. This modification can reduce the power consumption and the area of the circuit. This circuit also transfers the loading condition back to the external circuit by the load shift keying(LSK), determining if the input power is not enough or excessive, which increases the efficiency of the total system. The AC to DC converter is fabricated with the TSMC 90nm CMOS process. The circuit area is 0.071mm(2). The circuit can produce a 1V DC voltage with maximum output current of 10mA from an AC input ranging from 1.5V to 2V, at 1MHz to 10MHz. PMID:24110077

  18. AC Conductivity and Dielectric Relaxation Behavior of Sb2S3 Bulk Material

    Abd El-Rahman, K. F.; Darwish, A. A. A.; Qashou, Saleem I.; Hanafy, T. A.

    2016-07-01

    The Sb2S3 bulk material was used for next-generation anode for lithium-ion batteries. Alternative current (AC) conductivity, dielectric properties and electric modulus of Sb2S3 have been investigated. The measurements were carried out in the frequency range from 40 Hz to 5 MHz and temperature range from 293 K to 453 K. The direct current (DC) conductivity, σ DC, shows an activated behavior and the calculated activation energy is 0.50 eV. The AC conductivity, σ AC, was found to increase with the increase of temperature and frequency. The conduction mechanism of σ AC was controlled by the correlated barrier hopping model. The behavior of the dielectric constant, ɛ', and dielectric loss index, ɛ'', reveal that the polarization process of Sb2S3 is dipolar in nature. The behavior of both ɛ' and ɛ'' reveals that bulk Sb2S3 has no ferroelectric or piezoelectric phase transition. The dielectric modulus, M, gives a simple method for evaluating the activation energy of the dielectric relaxation. The calculated activation energy from M is 0.045 eV.

  19. Application of PEI–K2CO3/AC for capturing CO2 from flue gas after combustion

    Highlights: • A novel PEI–K2CO3/AC sorbent was prepared with the co-impregnation method. • The coupling characteristics of PEI and K2CO3 in the sorbent are expounded. • Both PEI and K2CO3 contribute to the total CO2 capture capacity of PEI–K2CO3/AC. • PEI–K2CO3/AC presents high CO2 capture capacity and long-term stability. • PEI–K2CO3/AC should be considered as a new option for post-combustion CO2 capture. - Abstract: The capture of CO2 from flue gas after combustion using solid sorbents is one of the efficient options for reducing CO2 emissions from fossil fuel-fired power plants. To satisfy the requirement of large quantities flue gas treatment, the CO2 capture capacities of the solid sorbents must be focused on. In order to obtain a sorbent with high CO2 capture capacity, a novel PEI–K2CO3/AC sorbent was prepared by impregnating potassium carbonate (K2CO3) and polyethylenimine (PEI) on activated carbon (AC) in this work. The CO2 capture performance of this sorbent was investigated using a fixed bed reactor system. The CO2 capture capacity of PEI–K2CO3/AC with the total K2CO3 and PEI loadings of 50 wt% was measured as 3.60 mmol CO2/g under the condition of 60 °C, 8% CO2 + 10% H2O. In addition, this sorbent is proved to be regenerable and stable during 5 cycle CO2 sorption–desorption tests. Compared with K2CO3/AC (loading of 58 wt%) and PEI/AC (loading of 43 wt%), PEI–K2CO3/AC presents higher CO2 capture capacity and long-term stability. Therefore, PEI–K2CO3/AC should be considered as a new option for capturing CO2 from flue gas after combustion

  20. Nuclear fuel

    It is expected that nuclear power generation will reach 49 million kW in 1985 and 129 million kW in 1995, and the nuclear fuel having to be supplied and processed will increase in proportion to these values. The technical problems concerning nuclear fuel are presented on the basis of the balance between the benefit for human beings and the burden on the human beings. Recently, especially the downstream of nuclear fuel attracts public attention. Enriched uranium as the raw material for light water reactor fuel is almost monopolized by the U.S., and the technical information has not been published for fear of the diversion to nuclear weapons. In this paper, the present situations of uranium enrichment, fuel fabrication, transportation, reprocessing and waste disposal and the future problems are described according to the path of nuclear fuel cycle. The demand and supply of enriched uranium in Japan will be balanced up to about 1988, but afterwards, the supply must rely upon the early establishment of the domestic technology by centrifugal separation method. No problem remains in the fabrication of light water reactor fuel, but for the fabrication of mixed oxide fuel, the mechanization of the production facility and labor saving are necessary. The solution of the capital risk for the construction of the second reprocessing plant is the main problem. Japan must develop waste disposal techniques with all-out efforts. (Kako, I.)

  1. Fuel cells:

    Sørensen, Bent

    2013-01-01

    A brief overview of the progress in fuel cell applications and basic technology development is presented, as a backdrop for discussing readiness for penetration into the marketplace as a solution to problems of depletion, safety, climate or environmental impact from currently used fossil and...... nuclear fuel-based energy technologies....

  2. Digital model for harmonic interactions in AC/DC/AC systems

    Guarini, A.P.; Rangel, R.D.; Pilotto, L.A.S.; Pinto, R.J.; Passos Junior, R. [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)

    1994-12-31

    The main purpose of this paper is to present a model for calculation of HVdc converter harmonics taking into account the influence of the harmonic interactions between the ac systems in dc link transmissions. The ideas and methodologies used in the model development take into account the dc current ripple and ac voltage distortion in the ac systems. The theory of switching functions is applied to contemplate for the frequency conversions between the ac and dc sides, in an iterative process. It is possible then to obtain, even in balanced situations, non-characteristic harmonics that are produced by frequencies originated in the other terminal, which can be significant in a strongly coupled system, such as back-to-back configuration. (author) 9 refs., 3 figs.

  3. A Comparison Between Two Average Modelling Techniques of AC-AC Power Converters

    Pawel Szczesniak

    2015-03-01

    Full Text Available In this paper, a comparative evaluation of two modelling tools for switching AC-AC power converters is presented. Both of them are based on average modelling techniques. The first approach is based on the circuit averaging technique and consists in the topological manipulations, applied to a converters states. The second approach makes use of state-space averaged model of the converter and is based on analytical manipulations using the different state representations of a converter. The two modelling techniques are applied to a same AC-AC converter called matrix-reactance frequency converter based on buck-boost topology. These techniques are compared on the basis of their rapidity, quantity of calculations and transformations and its limitations.

  4. High voltage AC/AC electrochemical capacitor operating at low temperature in salt aqueous electrolyte

    Abbas, Qamar; Béguin, François

    2016-06-01

    We demonstrate that an activated carbon (AC)-based electrochemical capacitor implementing aqueous lithium sulfate electrolyte in 7:3 vol:vol water/methanol mixture can operate down to -40 °C with good electrochemical performance. Three-electrode cell investigations show that the faradaic contributions related with hydrogen chemisorption in the negative AC electrode are thermodynamically unfavored at -40 °C, enabling the system to work as a typical electrical double-layer (EDL) capacitor. After prolonged floating of the AC/AC capacitor at 1.6 V and -40°C, the capacitance, equivalent series resistance and efficiency remain constant, demonstrating the absence of ageing related with side redox reactions at this temperature. Interestingly, when temperature is increased back to 24 °C, the redox behavior due to hydrogen storage reappears and the system behaves as a freshly prepared one.

  5. Kadanoff-Baym approach to time-dependent quantum transport in AC and DC fields

    We have developed a method based on the embedded Kadanoff-Baym equations to study the time evolution of open and inhomogeneous systems. The equation of motion for the Green's function on the Keldysh contour is solved using different conserving many-body approximations for the self-energy. Our formulation incorporates basic conservation laws, such as particle conservation, and includes both initial correlations and initial embedding effects, without restrictions on the time-dependence of the external driving field. We present results for the time-dependent density, current and dipole moment for a correlated tight binding chain connected to one-dimensional non-interacting leads exposed to DC and AC biases of various forms. We find that the self-consistent 2B and GW approximations are in extremely good agreement with each other at all times, for the long-range interactions that we consider. In the DC case we show that the oscillations in the transients can be understood from interchain and lead-chain transitions in the system and find that the dominant frequency corresponds to the HOMO-LUMO transition of the central wire. For AC biases with odd inversion symmetry odd harmonics to high harmonic order in the driving frequency are observed in the dipole moment, whereas for asymmetric applied bias also even harmonics have considerable intensity. In both cases we find that the HOMO-LUMO transition strongly mixes with the harmonics leading to harmonic peaks with enhanced intensity at the HOMO-LUMO transition energy.

  6. Rapid cycling synchrotron magnet with separate ac and dc circuit

    In present rapid cycling synchrotron magnets ac and dc currents flow in the same coil to give the desired field. The circuit reactance is made zero at dc and the operating frequency by running the magnet in series with an external parallel resonant LC current. We propose to return the ac flux in a gap next to the synchrotron. The dc coil encloses the ac magnetic circuit and thus links no ac flux. A shorted turn between the dc coil and ac flux enhances the separation of the two circuits. Several interesting developments are possible. The dc coil could be a stable superconductor to save power. The ac flux return gap could be identical with the synchrotron gap and contain a second synchrotron. This would double the output of the system. If the return flux gap were used for a booster, the ac coil power could be greatly reduced or radiation hardening of the ac coil could be simplified

  7. 76 FR 49525 - Advisory Circular 20-24C, Approval of Propulsion Fuels and Lubricating Oils

    2011-08-10

    ... adding fuels and oils to type certificates as engine, aircraft, or auxiliary power unit (APU) operating... adding fuels and oils as engine, aircraft, or APU operating limitations. These established methods..., aircraft, or APU operating limitations in lieu of the methods described in the AC. However, the EPD...

  8. Development of a 200kW multi-fuel type PAFC power plant

    Take, Tetsuo; Kuwata, Yutaka; Adachi, Masahito; Ogata, Tsutomu [NTT Integrated Information & Energy System Labs., Tokyo (Japan)

    1996-12-31

    Nippon Telegraph and Telephone Corporation (NFT) has been developing a 200 kW multi-fuel type PAFC power plant which can generate AC 200 kW of constant power by switching fuel from pipeline town gas to liquefied propane gas (LPG) and vice versa. This paper describes the outline of the demonstration test plant and test results of its fundamental characteristics.

  9. Design of Three Phase Matrix Converter AC-AC Utility Power Supply using SPWM Technique

    Sagar.S.Pawar; Prakash.T.Patil

    2015-01-01

    This paper describes the control analysis and design of an three phase matrix AC-AC utility power supply .The SPWM modulation techniques is used to control the desired output voltage and gives the control output voltage and reduced input harmonic distortions .In this Matrix converter Input is directly connected to output no DC link components is required. Simulation had been done using mat lab simulink and Simulated results are observed

  10. Design of Three Phase Matrix Converter AC-AC Utility Power Supply using SPWM Technique

    Sagar. S. Pawar

    2015-04-01

    Full Text Available This paper describes the control analysis and design of an three phase matrix AC-AC utility power supply .The SPWM modulation techniques is used to control the desired output voltage and gives the control output voltage and reduced input harmonic distortions .In this Matrix converter Input is directly connected to output no DC link components is required. Simulation had been done using mat lab simulink and Simulated results are observed

  11. A Comparison Between Two Average Modelling Techniques of AC-AC Power Converters

    Pawel Szczesniak

    2015-01-01

    In this paper, a comparative evaluation of two modelling tools for switching AC-AC power converters is presented. Both of them are based on average modelling techniques. The first approach is based on the circuit averaging technique and consists in the topological manipulations, applied to a converters states. The second approach makes use of state-space averaged model of the converter and is based on analytical manipulations using the different state representations of a converter. The two m...

  12. Approaches to building single-stage AC/AC conversion switch-mode audio power amplifiers

    Ljusev, P.; Andersen, Michael A.E.

    2005-07-01

    This paper discusses the possible topologies and promising approaches towards direct single-phase AC-AC conversion of the mains voltage for audio applications. When compared to standard Class-D switching audio power amplifiers with a separate power supply, it is expected that direct conversion will provide better efficiency and higher level of integration, leading to lower component count, volume and cost, but at the expense of a minor performance deterioration. (au)

  13. Implementation of Low Frequency Ac to High Frequency Ac with Single Stage Zvs-Pwm Inverter

    S. Arumugam S. Ramareddy M. Sridhar

    2011-01-01

    This paper presents a novel soft-switching pulse width modulation (PWM) utility frequency AC to high frequency (HF) AC power conversion circuit incorporating boost-active clamp single stage inverter topology. This power converter is more suitable and acceptable for cost effective HF consumer induction heating applications. Its operating principle is presented. The operating performances of this high frequency inverter using the latest insulated gate bipolar transistors are illustrated, which ...

  14. Adaptive Nonlinear Control of Induction Motors through AC/DC/AC Converters

    Elfadili, Abderrahim; Giri, Fouad; El Magri, Abdelmounime; Dugard, Luc; Chaoui, Fatima Zara

    2012-01-01

    The problem of controlling induction motors, together with associated AC/DC rectifiers and DC/AC inverters, is addressed. The control objectives are threefold: (i) the motor speed should track any reference signal despite mechanical parameter uncertainties and variations; (ii) the DC Link voltage must be tightly regulated; (iii) the power factor correction (PFC) w.r.t. the power supply net must be performed in a satisfactory way. First, a nonlinear model of the whole controlled system is deve...

  15. Robust control of synchronous motors through AC/DC/AC converters

    El Magri, Abdelmounime; Giri, Fouad; Abouloifa, Abdelmajid; Chaoui, Fatima Zara

    2010-01-01

    The problem of controlling synchronous motors, driven through AC/DC rectifiers and DC/AC inverters is addressed. The control objectives are three fold: (i) forcing the motor speed to track a varying reference signal in presence of motor parameter uncertainties;(ii) regulating the DC Link voltage; (iii )assuring a satisfactory power factor correction (PFC) with respect to the power supply net .First, a nonlinear model of the whole controlled system is developed in the Park-coordinates. Then, a...

  16. A new class of hybrid AC/AC direct power converters

    Klumpner, Christian; Wijekoon, Thiwanka; Wheeler, Patrick

    2005-01-01

    Variable voltage and variable frequency conversion of electrical energy from an AC source to an AC load is done in traditional power converters via a DC-link where an energy storage element (electrolytic capacitors) is situated. Despite its well-known benefits, it has the disadvantage of being bulky and to limit the converter lifetime. On the other hand, Direct Power Conversion (DPC) is an attractive concept, which doesn’t need an energy storage buffer, but has two main disadvantages: reduced...

  17. Approaches to building single-stage AC/AC conversion switch-mode audio power amplifiers

    Ljusev, Petar; Andersen, Michael Andreas E.

    2004-01-01

    This paper discusses the possible topologies and promising approaches towards direct single-phase AC-AC conversion of the mains voltage for audio applications. When compared to standard Class-D switching audio power amplifiers with a separate power supply, it is expected that direct conversion...... will provide better efficiency and higher level of integration, leading to lower component count, volume and cost, but at the expense of a minor performance deterioration....

  18. AC losses in a HTS coil carrying DC current in AC external magnetic field

    We electrically measured AC losses in a Bi2223/Ag-sheathed pancake coil excited by a DC current in AC external magnetic field. Losses in the coil contain two kinds of loss components that are the magnetization losses and dynamic resistance losses. In the measurement, current leads to supply a current to the coil were specially arranged to suppress electromagnetic coupling between the coil current and the AC external magnetic field. A double pick-up coils method was used to suppress a large inductive voltage component contained in voltage signal for measuring the magnetization losses. It was observed that the magnetization losses were dependent on the coil current and that a peak of a curve of the loss factor vs. amplitude of the AC external magnetic field shifted to lower amplitude of the AC magnetic field as the coil current increased. This result suggests the full penetration magnetic field of the coil tape decreases as the coil current increases. The dynamic resistance losses were measured by measuring a DC voltage appearing between the coil terminals. It was observed that the DC voltage appearing in the coil subject to the AC external magnetic field was much larger than that in the coil subject to DC magnetic field

  19. 21 CFR 880.5500 - AC-powered patient lift.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered patient lift. 880.5500 Section 880.5500... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either fixed or mobile, used to lift and transport patients in the horizontal or...

  20. [Humanitarian transition].

    Mattei, Jean-François; Troit, Virginie

    2016-02-01

    In two centuries, modern humanitarian action has experienced several fractures often linked to crises. Although its professionalism and intervention force remain indisputable, it faces, since the 2000s, a new context that limits its ability to act and confronts it with new dilemmas, even though it must deal with needs for aid of unprecedented scale. These difficulties reveal a humanitarian transition period that was not anticipated. This transition period reflects the change from a dominant paradigm of North-South solidarity of Western origin to a much more complex model. This article provides a summary of the current mutations that are dominated by the States' assertion of sovereignty. Among the possible solutions, it argues for an ethical approach and a better integration of the research carried out in the Global South, prerequisites for building a true partnership and placing the victims at the heart of the operations which involve them. PMID:26936180

  1. AC LED的研究现状与发展%Current research and development of AC LED

    满瑞; 李秋俊

    2012-01-01

    介绍了AC LED的特征及其工作原理,分析了AC LED相比于DC LED的优缺点,概述了AC LED在国内外的研究进展及其应用现状,讨论了AC LED技术发展过程中面临的挑战,并展望了其发展趋势.%The characteristics and operation principles of AC LED were presented.The advantages and disadvantages of AC LED compared with the DC LED were analyzed.The development and the latest application of AC LED were described.The challenges of the competition with the traditional light source were discussed,as well as the development trend of AC LED.

  2. Biodiesel/ULSD blend ratios by analysis of fuel properties

    Biodiesel is an alternative fuel that is made from vegetable oil or animal fat. Biodiesel is often blended with ultra low sulfur diesel (ULSD; 15 mg/kg maximum sulfur content) in volumetric ratios (VBD) of up to 20 vol% (B20). Government tax credits and other regulatory requirements may depend on ac...

  3. Dicty_cDB: FCL-AC08 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC08 (Link to dictyBase) - - - Contig-U15080-1 FCL-AC08P ...(Link to Original site) FCL-AC08F 616 FCL-AC08Z 291 FCL-AC08P 907 - - Show FCL-AC08 Library FCL (Link to library) Clone ID FCL-...-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-AC08Q....Seq.d/ Representative seq. ID FCL-AC08P (Link to Original site) Representative DNA sequence >FCL-AC08 (FCL-AC08Q) /CSM/FCL/FCL-...ignificant alignments: (bits) Value FCL-AC08 (FCL-AC08Q) /CSM/FCL/FCL-AC/FCL-AC08Q.Seq.d/ 1322 0.0 SFA226 (S

  4. Germany: energy transition or revolution

    Germany has decided to phase out nuclear power by 2022 but it wants also to get rid of fossil energies by 2050. Those ambitious goals imply to be able to cut by half the demand for primary energy by 2050 which will be only possible if the need for building heating is cut by 80%, the constraint on transport is less important: one million of electrical vehicles will have to be on the road by 2020 and 3 millions 10 years later. In 2012 the production of electricity was made mainly from coal (44.7%), renewable energies (21.9%), nuclear energy (16%), natural gas (11.3%) and other energies (fuel...) (6.1%). Today the renewable energy sector is a major industrial sector in Germany, it represents about 382000 jobs directly or indirectly, it means more than the sector of conventional energies. (A.C.)

  5. Standard Fire Behavior Fuel Models : A Comprehensive Set for Use with Rothermel's Surface Fire Spread Model

    Scott, Joe H; Burgan, Robert E

    2005-01-01

    This report describes a new set of standard fire behavior fuel models for use with Rothermel’s surface fire spread model and the relationship of the new set to the original set of 13 fire behavior fuel models. To assist with transition to using the new fuel models, a fuel model selection guide, fuel model crosswalk, and set of fuel model photos are provided.

  6. A nuclear reactor core fuel reload optimization using Artificial-Ant-Colony Connective Networks

    A Pressurized Water Reactor core must be reloaded every time the fuel burnup reaches a level when it is not possible to sustain nominal power operation. The nuclear core fuel reload optimization consists in finding a burned-up and fresh-fuel-assembly pattern that maximizes the number of full operational days. This problem is NP-hard, meaning that complexity grows exponentially with the number of fuel assemblies in the core. Besides that, the problem is non-linear and its search space is highly discontinual and multimodal. In this work a parallel computational system based on Ant Colony System (ACS) called Artificial-Ant-Colony Networks is introduced to solve the nuclear reactor core fuel reload optimization problem. ACS is a system based on artificial agents that uses the reinforcement learning technique and was originally developed to solve the Traveling Salesman Problem, which is conceptually similar to the nuclear fuel reload problem. (author)

  7. Fractional ac Josephson effect in unconventional superconductors

    For certain orientations of Josephson junctions between two px-wave or two d-wave superconductors, the subgap Andreev bound states produce a 4π-periodic relation between the Josephson current I and the phase difference ψ: I propor to sin(ψ/2) . Consequently, the ac Josephson current has the fractional frequency eV/h where V is the dc voltage. In the tunneling limit, the Josephson current is proportional to the first power (not square) of the electron tunneling amplitude. Thus, the Josephson current between unconventional superconductors is carried by single electrons, rather than by Cooper pairs. The fractional ac Josephson effect can be observed experimentally by measuring frequency spectrum of microwave radiation from the junction

  8. AC motor drive system for electric cars

    Morohoshi, Yukinobu; Yoshinori, Naoto; Naito, Hironobu (Fuji Electric Co., Ltd., Tokyo, (Japan))

    1989-08-10

    Various main circuit equipment with large capacity GTO thyristors are outlined for AC and DC electric cars. The configuration of a PWM converter system is presented for the AC main motor drive system of the Shinkansen trains, and its following features are described: the high power factor control capable of keeping a power factor 100% constantly, energy saving by power regenerative braking, the small triple structure with large capacity reverse-conducting GTO thyristors of 4,500V/3,000A, and the reduction of equivalent interfering current and harmonic current by three phase-triple phase difference operation. Furthermore, a control logic equipment with 16 bit MPU and a main transformer are outlined, and the verification test results of the control logic equipment by an analog model simulation and the combinational test results of the commercial equipment are reported. Prototype VVVF inverter system for DC electric cars is also presented. 6 refs., 13 figs., 3 tabs.

  9. β-delayed fission from 230Ac

    ThO2 is irradiated with 60 MeV/u 18O beams. 230Ra is produced via the multi-nucleon transfer and dissipative fragmentation reactions of the target. 230Ra is radio-chemical separated from ThO2 and the other reaction products. The thin Ra sources are prepared. The mica fission track detectors are exposed to the Ra sources. γ-rays of Ra decay in the sources are measured by a HPGe detector. The mica foil is etched in HF solution. The etched mica foil is scanned with an optical microscope. The fission tracks that should come from β-delayed fission of 230Ac are observed. The β-delayed fission probability of 230Ac is determined to be (1.19 +- 0.85) x 10-8

  10. Technological Change during the Energy Transition

    van der Meijden, Gerard; Smulders, Sjak

    2014-01-01

    The energy transition from fossil fuels to alternative energy sources has important consequences for technological change and resource extraction. We examine these consequences by incorporating a non-renewable resource and an alternative energy source in a market economy model of endogenous growth through expanding varieties. During the energy transition, technological progress is non-monotonic over time: it declines initially, starts increasing when the economy approaches the regime shift, a...

  11. Fuel cells

    D. N. Srivastava

    1962-05-01

    Full Text Available The current state of development of fuel cells as potential power sources is reviewed. Applications in special fields with particular reference to military requirements are pointed out.

  12. AC Dielectrophoresis Using Elliptic Electrode Geometry

    S. M. Rezaul Hasan; Aanan Khurma

    2011-01-01

    This paper presents negative AC dielectrophoretic investigations using elliptic electrode geometry. Simulations of the electric field gradient variation using various ratios of the semimajor and the semiminor axis were carried out to determine the optimum elliptic geometry for the dielectrophoretic electrokinetics of specimen in an assay with laminar (low Reynolds number) fluid flow. Experimental setup of the elliptic electrode assembly using PCB fabrication and electrokinetic accumulation of...

  13. Lazy AC-Pattern Matching for Rewriting

    Belkhir, Walid; 10.4204/EPTCS.82.3

    2012-01-01

    We define a lazy pattern-matching mechanism modulo associativity and commutativity. The solutions of a pattern-matching problem are stored in a lazy list composed of a first substitution at the head and a non-evaluated object that encodes the remaining computations. We integrate the lazy AC-matching in a strategy language: rewriting rule and strategy application produce a lazy list of terms.

  14. Entropy production in ac-calorimetry

    Garden, Jean-Luc; Richard, Jacques

    2007-01-01

    In calorimetry and particularly in heat capacity measurements, different characteristic relaxation time constants may perturb the experiment which cannot be considered at thermodynamic equilibrium. In this case, thermodynamics of irreversible processes has to be taken into account and the calorimetric measurements must be considered as dynamic. In a temperature modulated experiment, such as ac-calorimetry, these non-equilibrium experiments give rise to the notion of frequency dependent comple...

  15. Transit space

    Raahauge, Kirsten Marie

    2008-01-01

    This article deals with representations of one specific city, Århus, Denmark, especially its central district. The analysis is based on anthropological fieldwork conducted in Skåde Bakker and Fedet, two well-off neighborhoods. The overall purpose of the project is to study perceptions of space...... and the interaction of cultural, social, and spatial organizations, as seen from the point of view of people living in Skåde Bakker and Fedet. The focus is on the city dwellers’ representations of the central district of Århus with specific reference to the concept of transit space. When applied to various Århusian...

  16. Fuel assembly

    Purpose: To reconstruct a BWR type reactor into a high conversion reactor with no substantial changes for the reactor inner structure such as control rod structure. Constitution: The horizontal cross sectional shape of a channel box is reformed into a square configuration and the arrangement of fuel rods is formed as a trigonal lattice-like configuration. As a method of improving the conversion ratio, there is considered to use a dense lattice by narrowing the distance between fuel rods and trigonal lattice arrangement for fuel rod is advantageous therefor. A square shape cross sectional configuration having equal length both in the lateral and longitudinal directions is suitable for the channel box as a guide upon movement of the control rod. Fuel rods can be arranged with no loss by the trigonal lattice configuration, by which it is possible to improve the neutron moderation, increase the reactor core reactivity and conduct effective fuel combustion. In this way, it is possible to attain the object by inserting the follower portion of the control rod at the earier half and extracting the same at the latter half during the operation period in the reactor core comprising fuel assemblies suitable to a high conversion BWR type reactor having average conversion ratio of about 0.8. (Kamimura, M.)

  17. Fuel assembly

    The object of the present invention is to improve the hydrodynamic stability in the fuel channels of BWR type reactors and effectively utilize the coolant driving power corresponding to the reduction due to pressure loss. That is, in a fuel assembly having usual fuel rods and, in addition, water rods and short fuel rods, the structures of water rods, upper tie plates and the spacers are designed from a hydrodynamic point of view, to reduce the pressure loss. On the other hand, a lattice-like flow channel resistance member is disposed to a lower tie plate. The bundle flow rate is made uniform by the flow channel resistance member, and the pressure loss of the tie plate is increased by the reduction of the pressure loss by the arrangement of the short fuel rod and the reduction of the pressure loss described above. Since this increases the ratio of the single phase stream pressure loss in the total reactor core pressure loss, the hydrodynamic stability in the fuel channel is improved. (I.J.)

  18. About the transportation of WWER-type reactor spent nuclear fuel

    An intensive transition of existing NPPs with WWER-type reactors to new types of nuclear fuel and, therefore, to new fuel cycles, can be observed. New fuel cycles increase the burnup of nuclear fuel, and it increases the cost-effectiveness of its utilization

  19. Transitioning to Biofuels: A System-of-Systems Perspective; Preprint

    Riley, C.; Sandor, D.

    2008-06-01

    Using the existing fuel supply chain infrastructure as a framework, this paper discusses a vision for transitioning to a larger biofuels industry and the challenges associated with a massive market and infrastructure transformation.

  20. Development of a hardware-based AC microgrid for AC stability assessment

    Swanson, Robert R.

    As more power electronic-based devices enable the development of high-bandwidth AC microgrids, the topic of microgrid power distribution stability has become of increased interest. Recently, researchers have proposed a relatively straightforward method to assess the stability of AC systems based upon the time-constants of sources, the net bus capacitance, and the rate limits of sources. In this research, a focus has been to develop a hardware test system to evaluate AC system stability. As a first step, a time domain model of a two converter microgrid was established in which a three phase inverter acts as a power source and an active rectifier serves as an adjustable constant power AC load. The constant power load can be utilized to create rapid power flow transients to the generating system. As a second step, the inverter and active rectifier were designed using a Smart Power Module IGBT for switching and an embedded microcontroller as a processor for algorithm implementation. The inverter and active rectifier were designed to operate simultaneously using a synchronization signal to ensure each respective local controller operates in a common reference frame. Finally, the physical system was created and initial testing performed to validate the hardware functionality as a variable amplitude and variable frequency AC system.

  1. Dynamic Systems Analysis Report for Nuclear Fuel Recycle

    Brent Dixon; Sonny Kim; David Shropshire; Steven Piet; Gretchen Matthern; Bill Halsey

    2008-12-01

    This report examines the time-dependent dynamics of transitioning from the current United States (U.S.) nuclear fuel cycle where used nuclear fuel is disposed in a repository to a closed fuel cycle where the used fuel is recycled and only fission products and waste are disposed. The report is intended to help inform policy developers, decision makers, and program managers of system-level options and constraints as they guide the formulation and implementation of advanced fuel cycle development and demonstration efforts and move toward deployment of nuclear fuel recycling infrastructure.

  2. SQUID-based AC magnetometry down to 0.5 K made available on a widely-accessible platform

    In order to enable AC magnetometry with the 3He insert that has been designed for Quantum Design's MPMS SQUID magnetometer, we have calibrated the phase shift caused by the insert. Using gadolinium gallium garnet (GGG) as a zero-phase reference, we have succeeded in determining the phase contribution from the 3He insert down to about 0.5K, below which GGG develops a spin-glass-like transition. This means that AC magnetometry is now feasible down to 0.5 K for frequencies at least up to 100Hz on the common MPMS platform. At lower frequencies (≤ 1 Hz) virtually no phase shift is added by the 3He insert to the existing shift due to the MPMS sample tube. The sensitivity of the AC magnetization amplitude is estimated to be about 2 x 10-7 emu, although the AC susceptibility of the order of 1 x 10-4 emu shifted by ca. -2 x 10-6 emu when it was measured with the 3He insert, as compared to the normal measurement. This development is expected to facilitate studies of time-dependent magnetic phenomena, such as spin-glass transitions and quantum magnetization tunnelings of single-molecule magnets.

  3. Investigations on the flux pinning and an irreversibility line in different YBCO modifications by ac susceptibility measurements

    On polycrystalline specimens, melt grown thick films and sputtered thin films of YBa2Cu3O7-x we have investigated the imaginary part (χ'') of the ac susceptibility in dependence of frequency (1-50) kHz and ac amplitude (1 mOe-25 Oe). For the melt grown thick films and the sputtered thin films the observed loss-peak temperature (Tp) shifts only slightly to lower temperatures with increasing ac amplitude. This behavior is due to a strong flux-pinning mechanism. For the polycrystalline specimen the intergranular Tp decreases strongly with increasing ac amplitude above 1.5 Oe, resulting in a strong temperature dependence of the intergranular critical current density Jcj. With increasing frequency we observe an enhancement of Tp for all investigated YBCO modifications. From the frequency dependence of Tp we determine the flux pinning potential U0(T=0, HAC=0) to some eV. A irreversibility line was derived from the Tp dependence of the ac amplitude and will be discussed in terms of a phase transition from flux glass to flux flow. (orig.)

  4. Higher harmonics of ac voltage response in narrow strips of YBa2Cu3O7 thin films: evidence for strong thermal fluctuations

    We report on measurements of higher harmonics of the ac voltage response in strips of YBa2Cu3O7-δ thin films as a function of temperature, frequency and ac current amplitude. The third (fifth) harmonic of the local voltage is found to exhibit a negative (positive) peak at the superconducting transition temperature and their amplitudes are closely related to the slope (derivative) of the first (ohmic) harmonic. The peaks practically do not depend on frequency and no even (second or fourth) harmonics are detected. The observed data can be interpreted in terms of ac current induced thermal modulation of the sample temperature added to strong thermally activated fluctuations in the transition region

  5. Analysis and Comparison of Si and SiC Power Devices on a Grid-Tie Fuel Cell Energy Storage System

    Pittini, Riccardo; Anthon, Alexander; Zhang, Zhe;

    2014-01-01

    signif- icantly reduced switching and conduction losses in dc-dc and dc-ac converters allowing efficiencies above 98%. This paper analyzes the efficiency improvement that is achieved by the introduction of SiC power semiconductors in dc-dc and dc-ac converters. The analysis is focuses on fuel cell grid...

  6. Fuel assembly

    Since the neutron flux distribution and the power distribution of a fuel assembly in which short fuel rods vary greatly in the vicinity of a boundary where the distribution of uranium amount is different, the reading value of local power range monitors, having the detectors positioned in the vicinity of the boundary is varied. Then in the present invention, the upper end of the effective axial length of fuel rod is so made as not approaching with the detection position of the local power range monitor in a reactor core. Further, the upper end of the effective axial length of fuel rods in a 4 x 4 fuel rod lattice positioned at the corner on the side of the local power range monitor is so made as not approaching the detection position of the local power range monitor. As a result, the change of the neutron flux distribution and power distribution in the vicinity of the position where the detector of the local power range monitor is situated can be extremely reduced. Accordingly, there is no scattering and fluctuation for the reading value by the local power range monitor, to improve the monitoring performance for thermal characteristics in the reactor core. (N.H.)

  7. The legacy of fossil fuels

    Armaroli, N.; Balzani, V. [CNR, Bologna (Italy)

    2011-03-01

    Currently, over 80% of the energy used by mankind comes from fossil fuels. Harnessing coal, oil and gas, the energy resources contained in the store of our spaceship, Earth, has prompted a dramatic expansion in energy use and a substantial improvement in the quality of life of billions of individuals in some regions of the world. Powering our civilization with fossil fuels has been very convenient, but now we know that it entails severe consequences. We treat fossil fuels as a resource that anyone anywhere can extract and use in any fashion, and Earth's atmosphere, soil and oceans as a dump for their waste products, including more than 30 Gt/y of carbon dioxide. At present, environmental legacy rather than consistence of exploitable reserves, is the most dramatic problem posed by the relentless increase of fossil fuel global demand. Harmful effects on the environment and human health, usually not incorporated into the pricing of fossil fuels, include immediate and short-term impacts related to their discovery, extraction, transportation, distribution, and burning as well as climate change that are spread over time to future generations or over space to the entire planet. In this essay, several aspects of the fossil fuel legacy are discussed, such as alteration of the carbon cycle, carbon dioxide rise and its measurement, greenhouse effect, anthropogenic climate change, air pollution and human health, geoengineering proposals, land and water degradation, economic problems, indirect effects on the society, and the urgent need of regulatory efforts and related actions to promote a gradual transition out of the fossil fuel era. While manufacturing sustainable solar fuels appears to be a longer-time perspective, alternatives energy sources already exist that have the potential to replace fossil fuels as feedstocks for electricity production.

  8. The legacy of fossil fuels.

    Armaroli, Nicola; Balzani, Vincenzo

    2011-03-01

    Currently, over 80% of the energy used by mankind comes from fossil fuels. Harnessing coal, oil and gas, the energy resources contained in the store of our spaceship, Earth, has prompted a dramatic expansion in energy use and a substantial improvement in the quality of life of billions of individuals in some regions of the world. Powering our civilization with fossil fuels has been very convenient, but now we know that it entails severe consequences. We treat fossil fuels as a resource that anyone anywhere can extract and use in any fashion, and Earth's atmosphere, soil and oceans as a dump for their waste products, including more than 30 Gt/y of carbon dioxide. At present, environmental legacy rather than consistence of exploitable reserves, is the most dramatic problem posed by the relentless increase of fossil fuel global demand. Harmful effects on the environment and human health, usually not incorporated into the pricing of fossil fuels, include immediate and short-term impacts related to their discovery, extraction, transportation, distribution, and burning as well as climate change that are spread over time to future generations or over space to the entire planet. In this essay, several aspects of the fossil fuel legacy are discussed, such as alteration of the carbon cycle, carbon dioxide rise and its measurement, greenhouse effect, anthropogenic climate change, air pollution and human health, geoengineering proposals, land and water degradation, economic problems, indirect effects on the society, and the urgent need of regulatory efforts and related actions to promote a gradual transition out of the fossil fuel era. While manufacturing sustainable solar fuels appears to be a longer-time perspective, alternatives energy sources already exist that have the potential to replace fossil fuels as feedstocks for electricity production. PMID:21290608

  9. Sustainable Transition

    Hansen, Ole Erik; Søndergård, Bent

    2014-01-01

    agendas/vision, technologies, actors and institutions in the emergent design of an urban mobility system based on an electric car sharing system. Why. Designing for sustainability is a fundamental challenge for future design practices; designers have to obtain an ability to contribute to sustainable......What. The chapter addresses designing for sustainability as interventions in socio-technical systems and social practices of users and communities. It calls for reflexive design practices challenging dominant regimes and shaping alternative design spaces. The specific case is the reconfiguration of...... including the perspective of structural changes (transition of socio-technical systems and social practices) and Design as metadesign; an reflexivity on contextual framework of the design practice (regimes/design spaces)....

  10. Implementation of Low Frequency Ac to High Frequency Ac with Single Stage Zvs-Pwm Inverter

    S. Arumugam S. Ramareddy M. Sridhar

    2011-12-01

    Full Text Available This paper presents a novel soft-switching pulse width modulation (PWM utility frequency AC to high frequency (HF AC power conversion circuit incorporating boost-active clamp single stage inverter topology. This power converter is more suitable and acceptable for cost effective HF consumer induction heating applications. Its operating principle is presented. The operating performances of this high frequency inverter using the latest insulated gate bipolar transistors are illustrated, which includes HFAC power regulation ranges and actual efficiency characteristics based on zero voltage soft switching operation ranges.. The simulation circuits are models are developed and they are simulated using ORCAD.

  11. Implementation and Control of an AC/DC/AC Converter for Double Wound Flywheel Application

    Oliveira, J. G.; Schettino, H.; Gama, V; Carvalho, R.; H. Bernhoff

    2012-01-01

    An all-electric driveline based on a double wound flywheel, connected in series between main energy storage and a wheel motor, is presented. The flywheel works as a power buffer, allowing the battery to deliver optimized power. It also separates electrically the system in two sides, with the battery connected to the low voltage side and the wheel motor connected to the high voltage side. This paper presents the implementation and control of the AC/DC/AC converter, used to connect the flywheel...

  12. AcEST Contig - AcEST | LSDB Archive [Life Science Database Archive metadata

    Full Text Available [ Credit s ] BLAST Search Image Search Home About Archive Update History Contact us AcEST AcEST C ... c.jp/togodb/view/archive_acestcontig#en Data acquisit ion method - Data analysis method - Number of data ... entries 4,298 entries Data it em Description Contig ID ID of contig sequence of A ... ris Number of clones The number of EST clones constit uting the contig sequence of Adiantum capillus-vene ... ris Definit ion Definit ion Link to clone list In the TogoDB edi ...

  13. Realization of a Direct Soft Switching AC/AC Converter for Wireless Power Transfer Applications

    Vuorsalo, Simo

    2015-01-01

    This thesis describes the design, realization and testing of a three-phase to one-phase direct AC/AC converter, also known as the matrix converter. The switching is using the soft-switching strategy which is also known in the literature as the Zero Current Switching strategy. To achieve ZCS, the circuit needs resonant behavior which is achieved by the transmitter primary side that is an LC circuit. This circuit acts as a tank circuit and the switching frequency is the resonant frequency of th...

  14. Three-Level AC-DC-AC Z-Source Converter Using Reduced Passive Component Count

    Loh, Poh Chiang; Gao, Feng; Tan, Pee-Chin;

    2007-01-01

    This paper presents a three-level ac-dc-ac Z-source converter with output voltage buck-boost capability. The converter is implemented by connecting a low cost front-end diode rectifier to a neutral-point-clamped inverter through a single X-shaped LC impedance network. The inverter is controlled to...... low cost alternative to sensitive applications that need to ride-through frequent input voltage sags. For confirming the converter performance, experimental testing using a constructed laboratory prototype is performed with its captured results presented in a later section of the paper....

  15. Three-Level AC-DC-AC Z-Source Converter Using Reduced Passive Component Count

    Loh, Poh Chiang; Gao, Feng; Tan, Pee-Chin;

    2009-01-01

    This paper presents a three-level ac-dc-ac Z-source converter with output voltage buck-boost capability. The converter is implemented by connecting a low-cost front-end diode rectifier to a neutral-point-clamped inverter through a single X-shaped LC impedance network. The inverter is controlled to...... semiconductor commutations, and hence, no increase in switching losses. The proposed converter therefore offers a low-cost alternative to applications that need to ride through frequent input voltage sags. For confirming the converter performance, experimental testing using a constructed laboratory prototype is...

  16. Canadian power reactor fuel

    The following subjects are covered: the basic CANDU fuel design, the history of the bundle design, the significant differences between CANDU and LWR fuel, bundle manufacture, fissile and structural materials and coolants used in the CANDU fuel program, fuel and material behaviour, and performance under irradiation, fuel physics and management, booster rods and reactivity mechanisms, fuel procurement, organization and industry, and fuel costs. (author)

  17. AC Electric Field Activated Shape Memory Polymer Composite

    Kang, Jin Ho; Siochi, Emilie J.; Penner, Ronald K.; Turner, Travis L.

    2011-01-01

    Shape memory materials have drawn interest for applications like intelligent medical devices, deployable space structures and morphing structures. Compared to other shape memory materials like shape memory alloys (SMAs) or shape memory ceramics (SMCs), shape memory polymers (SMPs) have high elastic deformation that is amenable to tailored of mechanical properties, have lower density, and are easily processed. However, SMPs have low recovery stress and long response times. A new shape memory thermosetting polymer nanocomposite (LaRC-SMPC) was synthesized with conductive fillers to enhance its thermo-mechanical characteristics. A new composition of shape memory thermosetting polymer nanocomposite (LaRC-SMPC) was synthesized with conductive functionalized graphene sheets (FGS) to enhance its thermo-mechanical characteristics. The elastic modulus of LaRC-SMPC is approximately 2.7 GPa at room temperature and 4.3 MPa above its glass transition temperature. Conductive FGSs-doped LaRC-SMPC exhibited higher conductivity compared to pristine LaRC SMP. Applying an electric field at between 0.1 Hz and 1 kHz induced faster heating to activate the LaRC-SMPC s shape memory effect relative to applying DC electric field or AC electric field at frequencies exceeding1 kHz.

  18. AC susceptibility studies of the superconductivity of PrOs4Sb12

    We report the superconducting phase diagram of PrOs4Sb12 deduced from the real-part χ' and the imaginary part χ'' of the AC susceptibility. The double transition at Tc1=1.85K and Tc2=1.75K seen in the specific heat may be related to features in χ' and χ'', where full diamagnetic shielding is observed below Tc2 only. As function of magnetic field the phase bounded by Tc2 displays features reminiscent of the peak effect

  19. Ac susceptibility of Ho (Fe,CO){sub 11}Ti compounds and their hydrides

    Tabatabai Yazdi, Sh. [Department of Physics, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad 91755-1436 (Iran, Islamic Republic of); Motevalizadeh, L., E-mail: lmotevali@mshdiau.ac.ir [Department of Physics, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of)

    2015-04-01

    The structural characterization and ac susceptibility behavior of polycrystalline samples of HoFe{sub 11−x}Co{sub x}TiH{sub y} (x=1, 2, 4, 6, 7, 9, 11 and y=0, 1) intermetallics are investigated. All compounds crystallize in tetragonal ThMn{sub 12}-type structure. The replacement of Fe by Co causes the lattice constants to decrease, while hydrogen insertion leads to cell volume expansion. A spin-reorientation (SR) transition from a uniaxial to cone/planar structure is observed for the HoFe{sub 11−x}Co{sub x}Ti compounds of higher Co content (x>7). By hydrogenation, SR transition appears in all samples due to relative reinforcement of Ho contribution to anisotropy. T{sub SR} values increase by Co-content because of the preferential substitution of Fe by Co atoms and consequently, concentration-dependence of contribution of transition metal sublattice to anisotropy, as well as that of Ho. The concentration-dependence of magnetization direction and hydrogen-induced SR in the studied samples are discussed in the framework of two-magnetic sublattice model by bearing in mind the temperature-dependent competition of their anisotropies and dependence of magnetic anisotropy on crystal field interactions. - Highlights: • Ac susceptibility of HoFe{sub 11−x}Co{sub x}TiH{sub y} (x=1–11 and y=0, 1) intermetallics are investigated. • HoFe{sub 11−x}Co{sub x}Ti compounds of x>7 reveal an SR transition from uniaxial to cone/planar structure. • By hydrogenation, SR transition appears in all samples due to reinforcement of Ho anisotropy. • T{sub SR} values increase by Co-content because of the preferential substitution of Fe by Co atoms.

  20. Structure and AC conductivity of polycrystalline Pb(Cd1/3Nb2/3)O3

    K. Mroczka; K. Wójcik; Kajtoch, C.; W. Bąk

    2008-01-01

    Purpose: Purpose of this work was to determine crystalline structure and ac electric conductivity of polycrystalline sample Pb(Cd1/3Nb2/3)O3 (PCN) in paraelectric phase. Controversies involving uncertainties of phase transition character were the motivation of our experimental investigation: roentgenostructural, electron microscopy (SEM) and dielectric (ε’) as well as electric (σ’) spectroscopy.Design/methodology/approach: Polycrystalline PCN samples were prepared using hot pressing method. X...

  1. Lessons Learned on Fuel Cycle Simulation Dynamics

    Piet, S.J.; Dixon, B.W.; Jacobson, J.J.; Matthern, G.E.; Shropshire, D.E. [Idaho National Laboratory, 2525 North Fremont Mail Stop 3870, Idaho Falls, Idaho 83415-3870 (United States)

    2009-06-15

    Nuclear fuel cycles are inherently dynamic, yet many (if not most) comparisons of nuclear fuel cycle options compare them via static time-independent analyses. Instead, assessments need to consider dynamics in at least three senses - transitions from one fuel cycle strategy to another, how fuel cycles perform with nuclear power growth superimposed with time delays throughout the system, and variability of fuel cycle performance due to perturbations. This paper explains some of what we have learned from dynamic fuel cycle simulations using the VISION model. Dynamic analysis shows details not available through static analysis alone. - The fraction of fast reactors at any point in time will be much lower than predicted by simple 'static equilibrium' calculations due to multiple system constraints that impact the amount of TRU available for fueling new reactors at startup. - TRU management needs to account for both the TRU consumed in fast reactors and the additional TRU generation avoided due to fast reactors replacing some LWRs. - It is difficult to match the timing and size of deployment of reactors, separation plants, and fuel fabrication plants. - The holdup of transuranic material in the system impacts system performance so that short time lags (e.g. when facilities are co-located instead of at different locations) can lead to faster system evolution. - The higher the nuclear power growth rate, the higher the fast reactor TRU conversion ratio should be from the standpoint of uranium usage and the further the fast reactor fraction from static equilibrium. - The impact of transitioning to a closed fuel cycle on waste management is large and depends on processing loss rate and how long the closed fuel cycle has been implemented. - Fuel and separation facilities must accommodate variation in fuel mixture elemental composition. (authors)

  2. Fuel bundle

    This patent describes a method of forming a fuel bundle of a nuclear reactor. The method consists of positioning the fuel rods in the bottom plate, positioning the tie rod in the bottom plate with the key passed through the receptacle to the underside of the bottom plate and, after the tie rod is so positioned, turning the tie rod so that the key is in engagement with the underside of the bottom plate. Thereafter mounting the top plate is mounted in engagement with the fuel rods with the upper end of the tie rod extending through the opening in the top plate and extending above the top plate, and the tie rod is secured to the upper side of sid top plate thus simultaneously securing the key to the underside of the bottom plate

  3. Fuel flowmeters - measurements of fuel consumption

    Nešpor, Martin

    2012-01-01

    This work is devoted to measuring the fuel consumption. Generally deals with factors affecting consumption and fuels. Furthermore, it describes methods of measuring fuel consumption under the driving modes. Finally, the paper deals with the calculations, the actual selection of fuel gauge, economy and efficiency evaluation of fuel consumption. The conclusion of this work summarizes the above findings.

  4. Dicty_cDB: FCL-AC03 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC03 (Link to dictyBase) - - - Contig-U16477-1 FCL-AC03P ...(Link to Original site) FCL-AC03F 538 FCL-AC03Z 570 FCL-AC03P 1108 - - Show FCL-AC03 Library FCL (Link to library) Clone ID FCL-...7-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-AC03Q....Seq.d/ Representative seq. ID FCL-AC03P (Link to Original site) Representative DNA sequence >FCL-AC03 (FCL-AC03Q) /CSM/FCL/FCL-...AC/FCL-AC03Q.Seq.d/ AATTTTTAAAAAAAAAAGAAAATAAAAAAAAAAATAATATTTTATTAGTCATTATAAAAT TGTGAAT

  5. Dicty_cDB: FCL-AC20 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC20 (Link to dictyBase) - - - Contig-U15117-1 FCL-AC20Z ...(Link to Original site) - - FCL-AC20Z 600 - - - - Show FCL-AC20 Library FCL (Link to library) Clone ID FCL-A... http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-AC20Q.Seq.d/ Representative seq. ID FCL-...AC20Z (Link to Original site) Representative DNA sequence >FCL-AC20 (FCL-AC20Q) /CSM/FCL/FCL-AC/FCL-...Homology vs CSM-cDNA Score E Sequences producing significant alignments: (bits) Value FCL-AC20 (FCL-AC20Q) /CSM/FCL/FCL-AC/FCL-

  6. Levantamiento del campo acústico de una fuente sonora subacuática en el tanque hidroacústico del Instituto de Acústica

    Ranz Guerra, Carlos; Cobo, Pedro

    2000-01-01

    6 pp.-- PACS nrs.: 43.30.Jx, 43.30.Sf.-- Comunicación presentada en los siguientes congresos: Acústica 2000, II Congreso Iberoamericano de Acústica. XXXI Congreso Nacional de Acústica: TecniAcústica 2000. II Congreso Ibérico de Acústica. II Jornadas Iberoamericanas de Acústica. EAA Symposium on Architectural Acoustics.

  7. DC injection into low voltage AC networks

    NONE

    2005-07-01

    This report summarises the results of a study investigating the impact of levels of injected DC current injections on a low voltage AC distribution network systems in order to recommend acceptable limits of DC from microgeneration. Relevant literature is reviewed, and the impact of DC levels in distribution transformers, transformer modelling, and instrumental transformers are discussed. The impact of DC in residual current devices (RCD) and in domestic electricity watt hour meters is examined along with DC enhanced corrosion, corrosion failure, and the measurement of DC current injection. Sources of DC injection outlined include DC from computer power supplies, network faults, geomagnetic phenomena, lighting circuits/dimmers, and embedded generators.

  8. Mapa acústico parcial de Benetusser

    MORILLA CASTELLANOS, EMILIO

    2012-01-01

    Se establece el mapa de ruido del municipio de Benetússer para evaluar y conocer su exposición al ruido ambiental y así poder dar cumplimiento a la Directiva Europea sobre Gestión y Evaluación de Ruido Ambiental (2002/49/CE) y a la Ley nacional 37/2003 del Ruido. Los mapas estratégicos de ruido nos aportan la información fundamental para diagnosticar la situación acústica y para la gestión del ruido ambiental.

  9. An ac biased superconducting flux transformer

    The coupled motion of the vortex lattice of two electrically insulated, superimposed, superconducting thin films (primary and secondary) in a perpendicular magnetic field, is predicted to exhibit a Josephson-like behavior. For a dc applied current flowing in the primary film, the voltage difference between the time-averaged primary and secondary flux flow voltages obeys the equations of a resistively shunted junction model. If an ac current is superimposed on the dc current. Shapiro-type steps are predicted in the current-voltage characteristic. In contrast to the conventional Josephson effect, the voltage positions of these steps can be tuned by the applied magnetic field. (orig.)

  10. Flexible AC transmission systems modelling and control

    Zhang, Xiao-Ping; Pal, Bikash

    2012-01-01

    The extended and revised second edition of this successful monograph presents advanced modeling, analysis and control techniques of Flexible AC Transmission Systems (FACTS). The book covers comprehensively a range of power-system control problems: from steady-state voltage and power flow control, to voltage and reactive power control, to voltage stability control, to small signal stability control using FACTS controllers. In the six years since the first edition of the book has been published research on the FACTS has continued to flourish while renewable energy has developed into a mature and

  11. Long Beach Transit: Two-Year Evaluation of Gasoline-Electric Hybrid Transit Buses

    Lammert, M.

    2008-06-01

    This report focuses on a gasoline-electric hybrid transit bus propulsion system. The propulsion system is an alternative to standard diesel buses and allows for reductions in emissions (usually focused on reductions of particulate matter and oxides of nitrogen) and petroleum use. Gasoline propulsion is an alternative to diesel fuel and hybrid propulsion allows for increased fuel economy, which ultimately results in reduced petroleum use.

  12. Energy policy. Framework conditions for the transition from fossil fuels to renewable energies. Ambitions of energy policy in conflict with economic reality?; Energiepolitik. Rahmenbedingungen fuer die Entwicklung von fossilen Brennstoffen zu erneuerbaren Energien. Oekonomische Realitaet im Konflikt zu energiepolitischen Ambitionen?

    Reimer, Simon

    2011-07-01

    It is shown how the future development of individual renewable energy resources depends on whether statutory and other measures make it possible to achieve market penetration in conformity with competition law. Economic promotion of renewable energies is warranted for reasons of climate protection. However it is unclear to what extent renewable resources in their entirety can secure an economically sustainable energy supply. The present study looks at the possible future development of selected fossil fuels and renewable energy resources. It also examines what political framework conditions, instruments and measures might serve to steer this development and achieve envisioned goals.

  13. Transactions of the Second Annual Congress of the Sociedad Nuclear Mexicana A.C

    With no doubt, 1991 has been a good year for Nuclear Energy in Mexico. The record imposed by Laguna Verde Nuclear Power Plant, the first in his type in the world, operating without interruption in its first operating cycle, represents a splendid incentive for we all the nuclear workers. This fact is reflected in the percentage of papers presented in this congress, dealing with several aspects of Laguna Verde Central. This achievement should serve as an impulse for the development of other areas of application of nuclear energy in the country and at the same time be a reflection of the participation of the members of our society with good quality papers. In this Second Congress of Sociedad Nuclear Mexicana A.C., around thirty papers were presented in the technical sessions, in areas as: fuel management, radiation protection, reactor physics, transients analysis, nuclear materials and others. A special section is dedicated to present the experiences of the first fuel reload of Unit 1 in Laguna Verde Nuclear Power Plant,as well as different plenary meetings dedicated to subjects of general interest as advanced reactors, waste disposal and others. It is the wish of all the members of Sociedad Nuclear Mexicana A.C., that this annual meetings will be enriched with the enthusiastic participation of the scholars of nuclear field and that they represent the forum that we all need for the exchange of knowledge and experiences. (Author)

  14. Performance of an X-ray single pixel TES microcalorimeter under DC and AC biasing

    Gottardi, Luciano; de Korte, Piet A J; Hartog, Roland Den; Dirks, Bob; Popescu, Manuela; Hoevers, Henk F C; Bruijn, Marcel; Borderias, Maria Parra; Takei, Y

    2016-01-01

    We are developing Frequency Domain Multiplexing (FDM) for the read-out of TES imaging microcalorimeter arrays for future X-ray missions like IXO. In the FDMconfiguration the TES is AC voltage biased at a well defined frequencies (between 0.3 to 10MHz) and acts as an AM modulating element. In this paper we will present a full comparison of the performance of a TES microcalorimeter under DC bias and AC bias at a frequency of 370kHz. In both cases we measured the current-to-voltage characteristics, the complex impedance, the noise, the X-ray responsivity, and energy resolution. The behaviour is very similar in both cases, but deviations in performances are observed for detector working points low in the superconducting transition (R/RN < 0.5). The measured energy resolution at 5.89keV is 2.7eV for DC bias and 3.7eV for AC bias, while the baseline resolution is 2.8eV and 3.3eV, respectively.

  15. Evaluation of a.c. conductivity behaviour of graphite filled polysulphide modified epoxy composites

    Navin Chand; Deepak Jain

    2004-06-01

    Composites of epoxy resin having different amounts of graphite particles have been prepared by solution casting method. Temperature dependence of dielectric constant, tan and a.c. conductivity was measured in the frequency range, 1–20 kHz, temperature range, 40–180°C for 0.99, 1.96 and 2.91 wt% graphite filled and unfilled epoxy composites. It was observed that the dielectric constant, tan and a.c. conductivity increase with increasing temperature. Near the transition temperature the materials show anomalous behaviour for the observed properties. Peaks of dielectric constant, tan and a.c. conductivity were observed to shift towards lower temperature with increasing frequency. Clear relaxation (tan ) peaks around 169°C were observed in epoxy resin, which shifted to lower temperature side on increasing the frequency. Addition of 2.91 wt% graphite shifted the tan peaks towards higher temperature side by creating hindrances to the rotation of polymer dipoles. Addition of 2.91 wt% graphite leads to an increased relaxation time of dipoles in polysulphide epoxy from 1.44 × 10-5-3.92 × 10-5 (s) at 90°C by creating the hindrance to the rotation of dipoles.

  16. Performance of an X-ray single pixel TES microcalorimeter under DC and AC biasing

    We are developing Frequency Domain Multiplexing (FDM) for the read-out of TES imaging microcalorimeter arrays for future X-ray missions like IXO. In the FDM configuration the TES is AC voltage biased at a well defined frequencies (between 0.3 to 10 MHz) and acts as an AM modulating element. In this paper we will present a full comparison of the performance of a TES microcalorimeter under DC bias and AC bias at a frequency of 370 kHz. In both cases we measured the current-to-voltage characteristics, the complex impedance, the noise, the X-ray responsivity, and energy resolution. The behaviour is very similar in both cases, but deviations in performances are observed for detector working points low in the superconducting transition (R/RN<0.5). The measured energy resolution at 5.89 keV is 2.7 eV for DC bias and 3.7 eV for AC bias, while the baseline resolution is 2.8 eV and 3.3 eV, respectively.

  17. Transition from Training to Surgical Practice.

    Cogbill, Thomas H; Shapiro, Stephen B

    2016-02-01

    Surgical training graduates require a period of adjustment as they transform from trainees to experienced surgeons. Making a smooth transition is important for patient safety and new surgeon success. A subset of current graduates does not feel confident to enter directly into practice. Residency design with curriculum refocus, credentialing to encourage graded responsibility, and increased operative exposure is necessary. Onboarding programs should include formal mentoring, career counseling, proctoring by senior surgeons, and objective review of outcomes. The ACS developed a one-year TTP program to provide independent decision-making, operative autonomy, mentoring by senior surgeons, and practice management experience. PMID:26612017

  18. Reprogramming carcinoma associated fibroblasts by AC1MMYR2 impedes tumor metastasis and improves chemotherapy efficacy.

    Ren, Yu; Zhou, Xuan; Liu, Xia; Jia, Huan-Huan; Zhao, Xiao-Hui; Wang, Qi-Xue; Han, Lei; Song, Xin; Zhu, Zhi-Yan; Sun, Ting; Jiao, Hong-Xiao; Tian, Wei-Ping; Yang, Yu-Qi; Zhao, Xiu-Lan; Zhang, Lun; Mei, Mei; Kang, Chun-Sheng

    2016-04-28

    Carcinoma associated fibroblasts (CAFs) produce a nutrient-rich microenvironment to fuel tumor progression and metastasis. Reactive oxygen species (ROS) levels and the inflammation pathway co-operate to transform CAFs. Therefore, elucidating the mechanism mediating the activity of CAFs might identify novel therapies. Abnormal miR-21 expression was reported to be involved in the conversion of resident fibroblasts to CAFs, yet the factor that drives transformation was poorly understood. Here, we reported that high miR-21 expression was strongly associated with lymph node metastasis in breast cancer, and the activation of the miR-21/NF-кB was required for the metastatic promoting effect of CAFs. AC1MMYR2, a small molecule inhibitor of miR-21, attenuated NF-кB activity by directly targeting VHL, thereby blocking the co-precipitation of NF-кB and ß-catenin and nuclear translocation. Taxol failed to constrain the aggressive behavior of cancer cells stimulated by CAFs, whereas AC1MMYR2 plus taxol significantly suppressed tumor migration and invasion ability. Remodeling and depolarization of F-actin, decreased levels of β-catenin and vimentin, and increased E-cadherin were also detected in the combination therapy. Furthermore, reduced levels of FAP-α and α-SMA were observed, suggesting that AC1MMYR2 was competent to reprogram CAFs via the NF-кB/miR-21/VHL axis. Strikingly, a significant reduction of tumor growth and lung metastasis was observed in the combination treated mice. Taken together, our findings identified miR-21 as a critical mediator of metastasis in breast cancer through the tumor environment. AC1MMYR2 may be translated into the clinic and developed as a more personalized and effective neoadjuvant treatment for patients to reduce metastasis and improve the chemotherapy response. PMID:26872723

  19. Transition time

    Carlos Renato Zacharias

    2013-03-01

    Full Text Available 2013 is going to be an interesting year for the High Dilution research field. There is a tendency to revise basic concepts and common beliefs, while refining models and theories. The fundamental research team seems to be open to deeper discussions, aiming to reinforce some hypothesis and discharge others. In somehow, we are stuck in a vicious way of think, trying to manage and describe an informational phenomenon into a molecular framework. The challenge offered to those researchers involved with basic science is to figure out how to deal with such phenomenon, since previous theories and models have not shown to be matched! In the other hand, there is a tendency to explore the HD phenomenon in its technological branch. While basic research is important to describe how things work, the applied research has a more intense social and economic appeal. To develop technology based on HD means to give a different kind of visibility to the field, attracting sponsors, companies, entrepreneurs, always committed to the market regulatory laws. I am expecting for this year some important movements, both in the basic and applied research. Of course, it will be only a new beginning, as these changes require a lot of work, discussions and insights. But this transition time is very welcome!

  20. Transport fuel

    Ronsse, Frederik; Jørgensen, Henning; Schüßler, Ingmar;

    2014-01-01

    Worldwide, the use of transport fuel derived from biomass increased four-fold between 2003 and 2012. Mainly based on food resources, these conventional biofuels did not achieve the expected emission savings and contributed to higher prices for food commod - ities, especially maize and oilseeds...

  1. Fuel assembly

    Fuel rods are arranged in a lattice-like structure by way of a plurality of spacers and the lower ends thereof are fixed to a lower tie plate for assembling a fuel rod bundle. The outer circumference is surrounded by a basket having a plurality of openings and the basket is surrounded by a channel box. The basket is connected to a handle at the upper end and to a lower tie plate at the lower end and, further, defined with a scraper at each of openings. Coolants flown from the lower tie plate to the channel box flow the channels between the channel box and the basket and a fuel rod bundle, uprise while forming a two-phase flow and flow out from the upper end of the channel box. Since no upper tie plate is present, pressure loss of coolants flow is reduced, and liquid membranes of coolants are peeled off by the scraper disposed at the opening of the basket, which contributes to the improvement of the limit power. In addition, fuel rods are inspected and cleaned easily. (N.H.)

  2. Characterization of the 309 fuel examination facility

    Greenhalgh, W.O.; Cornwell, B.C.

    1997-07-09

    This document identifies radiological, chemical and physical conditions inside the Fuel Examination Facility. It is located inside the Plutonium Recycle Test Reactor containment structure (309 Building.) The facility was a hot cell used for examination of PRTR fuel and equipment during the 1960`s. Located inside the cell is a PRTR shim rod assembly, reported are radiological conditions of the sample. The conditions were assessed as part of overall 309 Building transition.

  3. Characterization of the 309 fuel examination facility

    This document identifies radiological, chemical and physical conditions inside the Fuel Examination Facility. It is located inside the Plutonium Recycle Test Reactor containment structure (309 Building.) The facility was a hot cell used for examination of PRTR fuel and equipment during the 1960's. Located inside the cell is a PRTR shim rod assembly, reported are radiological conditions of the sample. The conditions were assessed as part of overall 309 Building transition

  4. Estudio acústico del Conservatorio de Piles

    VILLA MORANT, SARA

    2014-01-01

    El objetivo de este proyecto es realizar un estudio acústico general de la "Casa de la Cultura" de Piles, sobre todo de los recintos que más lo requieren, como la sala principal de música. El edificio, al tratarse de una construcción antigua, no reúne las especificaciones acústicas establecidas en el Código Técnico vigente en la actualidad. En primer lugar, se realiza el estudio del acondicionamiento acústico de la sala principal, entendiéndose como acondicionamiento acústico la definición de...

  5. AC Own Motion Percentage of Randomly Sampled Cases

    Social Security Administration — Longitudinal report detailing the numbers and percentages of Appeals Council (AC) own motion review actions taken on un-appealed favorable hearing level decisions...

  6. AC electric motors control advanced design techniques and applications

    Giri, Fouad

    2013-01-01

    The complexity of AC motor control lies in the multivariable and nonlinear nature of AC machine dynamics. Recent advancements in control theory now make it possible to deal with long-standing problems in AC motors control. This text expertly draws on these developments to apply a wide range of model-based control designmethods to a variety of AC motors. Contributions from over thirty top researchers explain how modern control design methods can be used to achieve tight speed regulation, optimal energetic efficiency, and operation reliability and safety, by considering online state var

  7. Study of AC electrical conduction mechanisms in an epoxy polymer

    Jilani, Wissal; Mzabi, Nissaf; Gallot-Lavallée, Olivier; Fourati, Najla; Zerrouki, Chouki; Zerrouki, Rachida; Guermazi, Hajer

    2015-11-01

    The AC conductivity of an epoxy resin was investigated in the frequency range 10^{-1} - 106 Hz at temperatures ranging from -100 to 120 °C. The frequency dependence of σ_{ac} was described by the law: σ_{ac}=ω \\varepsilon0\\varepsilon^''_{HN}+Aωs. The study of temperature variation of the exponent (s) reveals two conduction models: the AC conduction dependence upon temperature is governed by the small polaron tunneling mechanism (SPTM) at low temperature (-100 -60 °C) and the correlated barrier hopping (CHB) model at high temperature (80-120 °C).

  8. An improved AC-amplifier for electrophysiology

    Jorgovanović Nikola

    2009-01-01

    Full Text Available We present the design, simulation and test results of a new AC amplifier for electrophysiological measurements based on a three op-amp instrumentation amplifier (IA. The design target was to increase the common mode rejection ratio (CMRR, thereby improving the quality of the recorded physiological signals in a noisy environment. The new amplifier actively suppresses the DC component of the differential signal and actively reduces the common mode signal in the first stage of the IA. These functions increase the dynamic range of the amplifier's first stage of the differential signal. The next step was the realization of the amplifier in a single chip technology. The design and tests of the new AC amplifier with a differential gain of 79.2 dB, a CMRR of 130 dB at 50 Hz, a high-pass cutoff frequency at 0.01 Hz and common mode reduction in the first stage of the 49.8 dB are presented in this paper.

  9. Fuel cells technologies for fuel processing

    Shekhawat, Dushyant, II; Berry, David A, I

    2014-01-01

    Fuel Cells: Technologies for Fuel Processing provides an overview of the most important aspects of fuel reforming to the generally interested reader, researcher, technologist, teacher, student, or engineer. The topics covered include all aspects of fuel reforming: fundamental chemistry, different modes of reforming, catalysts, catalyst deactivation, fuel desulfurization, reaction engineering, novel reforming concepts, thermodynamics, heat and mass transfer issues, system design, and recent research and development. While no attempt is made to describe the fuel cell itself, there is sufficient

  10. Hydrogen: energy transition under way

    Written by a representative of Air Liquide with the help of a free lance journalist, this book proposes an overview of the technological developments for the use of hydrogen as a clean energy with its ability to store primary energy (notably that produced by renewable sources), and its capacity of energy restitution in combination with a fuel cell with many different applications (notably mobility-related applications). The authors outline that these developments are very important in a context of energy transition. They also outline what is left to be done, notably economically and financially, for hydrogen to play its role in the energy revolution which is now under way

  11. Dicty_cDB: FCL-AC29 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC29 (Link to dictyBase) - - - Contig-U15392-1 FCL-AC29P ...(Link to Original site) FCL-AC29F 104 FCL-AC29Z 591 FCL-AC29P 695 - - Show FCL-AC29 Library FCL (Link to library) Clone ID FCL-...-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-AC29Q....Seq.d/ Representative seq. ID FCL-AC29P (Link to Original site) Representative DNA sequence >FCL-AC29 (FCL-AC29Q) /CSM/FCL/FCL-...roducing significant alignments: (bits) Value VSC293 (VSC293Q) /CSM/VS/VSC2-D/VSC293Q.Seq.d/ 1063 0.0 FCL-AC29 (FCL-

  12. Fuel review: fuel design data

    Tables of data are provided which give the specifications of fuel designs from a number of fabricators. The reactor types covered are: PWR; VVER; BWR; and Heavy Water. One or two illustrations of representative designs for each manufacturer are included. An address list of suppliers is appended. (UK)

  13. A Non-linear Controller for Single-Phase AC-AC Power Converter to meet UPS Performance Index

    Abdelhafid Ait Elmahjoub

    2012-07-01

    Full Text Available This article focuses on AC-AC power converter that can be used for uninterruptible power supply (UPS. The converter is built on two stages: a AC-DC input stage and a DC-AC output stage. The two blocks are connected by an intermediate DC bus. The aim of control is threefold: i power factor correction ii regulation of DC bus iii generating a sinusoidal voltage at the output. The synthesis of controllers has been achieved through the technique of nonlinear backstepping control. A detailed analysis of the stability control system is presented. The performances of regulators have been validated by numerical simulation in MATLAB / SIMULINK.

  14. Advanced passive PWR AC-600: Development orientation of nuclear power reactors in China for the next century

    Based on Qinshan II Nuclear Power Plant that is designed and constructed by way of self-reliance, China has developed advanced passive PWR AC-600. The design concept of AC-600 not only takes the real situation of China into consideration, but also follows the developing trend of nuclear power in the world. The design of AC-600 has the following technical characteristics: Advanced reactor: 18-24 month fuel cycle, low neutron leakage, low power density of the core, no any penetration in the RPV below the level of the reactor coolant nozzles; Passive safety systems: passive emergency residual heat removal system, passive-active safety injection system, passive containment cooling system and main control room habitability system; System simplified and the number of components reduced; Digital I and C; Modular construction. AC-600 inherits the proven technology China has mastered and used in Qirtshan 11, and absorbs advanced international design concepts, but it also has a distinctive characteristic of bringing forth new ideas independently. It is suited to Chinese conditions and therefore is expected to become an orientation of nuclear power development by self-reliance in China for the next century. (author)

  15. Effect of electric fields on the stabilization of premixed laminar bunsen flames at low AC frequency: Bi-ionic wind effect

    Kim, Minkuk

    2012-03-01

    The stabilization characteristics of laminar premixed bunsen flames have been investigated experimentally by applying AC electric fields at low frequency below 60. Hz together with DC in the single electrode configuration. The blowoff velocity has been measured for varying AC voltage and frequency. A transition frequency between low and high frequency regimes has been identified near 40-50. Hz, where AC electric fields have minimal effect on flame stabilization. In the low frequency regime, the blowoff velocity decreased linearly with AC voltage such that the flames became less stable. This was consistent with the DC result, implying the influence of the ionic wind effect. The variation of blowoff velocity with AC frequency showed a non-monotonic behavior in that the velocity decreased and then increased, exhibiting minimum blowoff velocity near 6-8. Hz. Based on the molecular kinetic theory, the developing degree of ionic wind was derived. By considering the ionic wind effects arising from both positive and negative ions in a flame zone, the bi-ionic wind effect successfully explained the non-monotonic behavior of blowoff velocity with AC frequency in the low frequency regime. © 2011 The Combustion Institute.

  16. [Intestinal occlusion and abdominal compartment syndrome (ACS)].

    Stagnitti, Franco

    2009-01-01

    Intestinal occlusion is defined as an independent predictive factor of intra-abdominal hypertension (IAH) which represents an independent predictor of mortality. Baggot in 1951 classified patients operated with intestinal occlusion as being at risk for IAH ("abdominal blow-out"), recommending them for open abdomen surgery proposed by Ogilvie. Abdominal surgery provokes IAH in 44.7% of cases with mortality which, in emergency, triples with respect to elective surgery (21.9% vs 6.8%). In particular, IAH is present in 61.2% of ileus and bowel distension and is responsible for 52% of mortality (54.8% in cases with intra-abdominal infection). These patients present with an increasing intra-abdominal pressure (IAP) which, over 20-25 mmHg, triggers an Abdominal Compartment Syndrome (ACS) with altered functions in some organs arriving at Multiple Organ Dysfunction Syndrome (MODS). The intestine normally covers 58% of abdominal volume but when there is ileus distension, intestinal pneumatosis develops (third space) which can occupy up to 90% of the entire cavity. At this moment, Gastro Intestinal Failure (GIF) can appear, which is a specific independent risk factor of mortality, motor of "Organ Failure". The pathophysiological evolution has many factors in 45% of cases: intestinal pneumatosis is associated with mucosal and serous edema, capillary leakage with an increase in extra-cellular volume and peritoneal fluid collections (fourth space). The successive loss of the mucous barrier permits a bacterial translocation which includes bacteria, toxins, pro-inflammatory factors and oxygen free radicals facilitating the passage from an intra-abdominal to inter-systemic vicious cyrcle. IAH provokes the raising of the diaphragm, and vascular and visceral compressions which induce hypertension in the various spaces with compartmental characteristics. These trigger hypertension in the renal, hepatic, pelvic, thoracic, cardiac, intracranial, orbital and lower extremity areas, giving

  17. Fuel trading

    A first part of this report proposes an overview of trends and predictions. After a synthesis on the sector changes and trends, it indicates and comments the most recent predictions for the consumption of refined oil products and for the turnover of the fuel wholesale market, reports the main highlights concerning the sector's life, and gives a dashboard of the sector activity. The second part proposes the annual report on trends and competition. It presents the main operator profiles and fuel categories, the main determining factors of the activity, the evolution of the sector context between 2005 and 2015 (consumptions, prices, temperature evolution). It analyses the evolution of the sector activity and indicators (sales, turnovers, prices, imports). Financial performances of enterprises are presented. The economic structure of the sector is described (evolution of the economic fabric, structural characteristics, French foreign trade). Actors are then presented and ranked in terms of turnover, of added value, and of result

  18. Enhanced Activated Carbon Cathode Performance for Microbial Fuel Cell by Blending Carbon Black

    Zhang, Xiaoyuan

    2014-02-04

    Activated carbon (AC) is a useful and environmentally sustainable catalyst for oxygen reduction in air-cathode microbial fuel cells (MFCs), but there is great interest in improving its performance and longevity. To enhance the performance of AC cathodes, carbon black (CB) was added into AC at CB:AC ratios of 0, 2, 5, 10, and 15 wt % to increase electrical conductivity and facilitate electron transfer. AC cathodes were then evaluated in both MFCs and electrochemical cells and compared to reactors with cathodes made with Pt. Maximum power densities of MFCs were increased by 9-16% with CB compared to the plain AC in the first week. The optimal CB:AC ratio was 10% based on both MFC polarization tests and three electrode electrochemical tests. The maximum power density of the 10% CB cathode was initially 1560 ± 40 mW/m2 and decreased by only 7% after 5 months of operation compared to a 61% decrease for the control (Pt catalyst, 570 ± 30 mW/m2 after 5 months). The catalytic activities of Pt and AC (plain or with 10% CB) were further examined in rotating disk electrode (RDE) tests that minimized mass transfer limitations. The RDE tests showed that the limiting current of the AC with 10% CB was improved by up to 21% primarily due to a decrease in charge transfer resistance (25%). These results show that blending CB in AC is a simple and effective strategy to enhance AC cathode performance in MFCs and that further improvement in performance could be obtained by reducing mass transfer limitations. © 2014 American Chemical Society.

  19. Transitions: A Personal Perspective.

    Wood, Ann Stace

    1995-01-01

    Distinguishes between unchosen transitions (children maturing and leaving, parents aging, companies downsizing) and chosen ones (moving, divorce, marriage, career changes). Describes the steps one goes through: uneasiness, renewed energy, complaining, exploration, partial transition, and the completed transition. (JOW)

  20. Transition to Adulthood

    ... Parent Center PTACs Workspaces Log-in Search for: Transition to Adulthood Link-checked, June 2016 A legacy ... Resources of more info _________________________ A Quick Summary of Transition Transition services are intended to prepare students to ...

  1. Fuel assembly

    The cross section of a fuel assembly is divided to a first region containing corner portions at which channel fasteners are situated and a second region not containing corner portions. The average enrichment degree of plutonium in the first region is decreased than that of the second region, and the number of fuel rods containing burnable poisons is increased at the first region than that of the second region. In the first region of the fuel assembly, the effect of moderating neutrons is enhanced since the cross section of a moderator flow channel at the outer side of the channel box is large. Therefore, local power peaking is increased in the first region while it is decreased in the second region that opposes to a narrow gap. The average enrichment degree of plutonium in the first region is decreased and that in the second region is increased by so much, to flatten the power distribution. Then, the reduction of the reactivity worth of gadolinia, as burnable poisons, can be suppressed. (N.H.)

  2. Fuel assembly

    The present invention concerns a fuel assembly of a BWR type reactor, and prevents aging change of flow rate of coolants leaked from a gap between a lower tie plate and a channel box. That is, in the fuel assembly, a great number of fuel rods and a plurality of water rods are bundled by a plurality of spacers, the upper and the lower ends thereof are supported by upper and lower tie plates, and they are contained in a channel box. Plate-like protrusions are disposed rotatably to the lower tie plate at a position corresponding to the lower end of the channel box. In addition, through holes are disposed on the side wall of the lower tie plate. With such a constitution, the protrusions rotate at a connection portion by hydraulic pressure of leaking coolants, and urge the channel box by the other end to control leakage of coolants. Further, since the through holes are disposed on the side wall of the lower tie plate, pressure difference is caused between the upper and the lower surfaces of the plate of the protrusion, to rotate the protrusions at the connection portion, and the other end of the protrusions presses the channel box to obtain the same effect. (I.S.)

  3. Fuel rod

    The present invention provide a fuel rod used in a BWR type reactor, preventing the occurrence of defects of weld portions and improving the operationability of test and assembling operation to improve the quality of weld portions. Namely, the fuel rod is formed by loading a plurality of fuel pellets in a cladding tube. The outer diameter of a groove portion of a tightly sealing end plug to be inserted and welded to the open end of the cladding tube is made substantially identical with the inner diameter of the cladding tube. A neck portion having a diameter smaller than the outer diameter of the groove portion is disposed between an end plug main body and the groove portion. As a result, since the outer diameter of the groove portion is substantially identical with the inner diameter of the cladding tube, the positioning is facilitated. Since the neck portion having a smaller diameter than the outer diameter of the groove portion is disposed in the groove portion, a gap is formed in the welded portion thereby enabling to facilitate the confirmation of weld sag for confirming integrity of the weld by a non-destructive test. (I.S.)

  4. Cooperative Frequency Control for Autonomous AC Microgrids

    Shafiee, Qobad; Quintero, Juan Carlos Vasquez; Guerrero, Josep M.; Nasirian, Vahidreza; Davoudi, Ali

    2015-01-01

    Distributed secondary control strategies have been recently studied for frequency regulation in droop-based AC Microgrids. Unlike centralized secondary control, the distributed one might fail to provide frequency synchronization and proportional active power sharing simultaneously, due to having...... different control parameters. This paper introduces a cooperative algorithm that regulates the system frequency while maintaining the power sharing properties of droop control. Dynamic consensus protocol is used to estimate the average of normalized active powers in the entire MG. This estimation is then...... added to primary control, compensating the frequency drop caused by the droop mechanism. The proposed controller is fully distributed, meaning that each source exchange information with only its direct neighbors through a sparse communication network. This controller has a unique feature that it does...

  5. Mapa Acústico del Gran Madrid

    Santiago Páez, José Salvador; Perera, P

    2006-01-01

    El desarrollo urbanístico de Madrid desde los años 1980 a finales de la década de los 90 hizo que su Ayuntamiento, que ya había promovido la realización entre 1985 y 1991 de un Mapa Acústico parcial de la ciudad, pensase en extender el ámbito de éste a todo el término municipal. Siguiendo el mismo criterio anterior, se superpuso una cuadrícula sobre el plano de Madrid, y se llevaron a cabo registros sonoros de 5 minutos en cada vértice de la misma, en los puntos de medición fuera del área ant...

  6. Josephson arrays for dc and ac metrology

    Large series arrays of underdamped SIS tunnel junctions are the basic element of the primary dc voltage standards used at present. The development of versatile quantum voltmeters for dc and ac metrology requires the preparation of large and perfect series arrays of overdamped Josephson junctions. Overdamped junctions can be realized by externally shunted SIS junctions or by internally shunted SNS or SINIS junctions. Arrays of up to 8000 SINIS junctions or 30000 SNS junctions were successfully operated at the 1 V dc level. In addition to being used in large arrays for voltage metrology and oscillators, the described junction types may become very useful for the preparation of highly integrated single-flux-quantum digital devices. (author)

  7. An ac bridge readout for bolometric detectors

    Rieke, F. M.; Lange, A. E.; Beeman, J. W.; Haller, E. E.

    1989-01-01

    The authors have developed a bolometer readout circuit which greatly improves the low-frequency stability of bolometric detectors. The circuit uses an ac bias voltage and two matched bolometers and allows stable dc bolometer operation for integration times greater than 10 s. In astronomical applications the readout allows for qualitatively different observation modes (e.g. staring or slow-drift scanning) which are particularly well suited for space observations and for the use of arrays. In many applications the readout can increase sensitivity. The authors present noise spectra for 4He temperature bolometers with no excess noise at frequencies greater than 0.1 Hz. The measured optical responsivity of a bolometer operated with the present readout is the same as that of a bolometer operated with a conventional readout.

  8. Composite Based EHV AC Overhead Transmission Lines

    Sørensen, Thomas Kjærsgaard

    Overhead lines at transmission level are the backbone of any national power grid today. New overhead line projects however are at the same time subject to ever greater public resistance due to the lines environmental impact. As full undergrounding of transmission lines at extra high voltage (EHV......) levels are still not seen as possibility, the future expansion of transmission grids are dependent on new solutions with lessened environment impact, especially with regard to the visual impact. In the present Thesis, composite materials and composite based overhead line components are presented and...... analysed with regard to the possibilities, limitations and risks widespread application of composite materials on EHV AC overhead transmission lines may present. To form the basis for evaluation of the useability of composite materials, dierent overhead line projects aimed at reducing the environmental...

  9. Effective ac response in weakly nonlinear composites

    Wei Enbo [Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China); Yang Zidong [College of Power Engineering, University of Shanghai Science and Technology, Shanghai 200093 (China); Gu Guoqing [Information College of Science and Technology, East China Normal University, Shanghai 200062 (China)

    2004-01-07

    The perturbation method is developed to deal with the problem of determining the effective nonlinear conductivity of Kerr-like nonlinear media under an external ac electric field. As an example, we have considered the cylindrical inclusion embedded in a host under the sinusoidal external field E{sub 1} sin (<{omega}t) + E{sub 3} sin (3<{omega}t) with frequencies{omega} and 3{omega}. The potentials of composites at higher harmonics are derived in both local inclusion particle and host regions. The effective responses of bulk nonlinear composites at basic frequency and harmonics are given for cylindrical composites in the dilute limit. Moreover, the relationships between the nonlinear effective responses at the basic frequency and the third harmonics are derived.

  10. Modeling of long High Voltage AC Underground

    Gudmundsdottir, Unnur Stella; Bak, Claus Leth; Wiechowski, W. T.

    2010-01-01

    This paper presents the work and findings of a PhD project focused on accurate high frequency modelling of long High Voltage AC Underground cables. The project is cooperation between Aalborg University and Energinet.dk. The objective of the project is to investigate the accuracy of most up to date...... cable models, perform highly accurate field measurements for validating the model and identifying possible disadvantages of the cable model. Furthermore the project suggests and implements improvements and validates them against several field measurements. It is shown in this paper how a new method for...... calculating the frequency dependent cables impedance greatly improves the modeling procedure and gives a highly accurate result for high frequency simulations....

  11. Nonlinear ac conductivity of interacting 1d electron systems

    Rosenow, Bernd; Nattermann, Thomas

    2004-01-01

    We consider low energy charge transport in one-dimensional (1d) electron systems with short range interactions under the influence of a random potential. Combining RG and instanton methods, we calculate the nonlinear ac conductivity and discuss the crossover between the nonanalytic field dependence of the electric current at zero frequency and the linear ac conductivity at small electric fields and finite frequency.

  12. Flexible AC transmission systems: the state of the art

    Edris, Abdel-Aty [Electric Power Research Inst., Palo Alto, CA (United States). Electric Systems Division

    1994-12-31

    Flexible AC transmission systems (FACTS) is a concept promoting the use of power electronic controllers to enhance the controllability and usable capacity of AC transmission. This paper presents the state of the art of FACTS and the status of the current projects for the application of the FACTS controllers in transmission systems. (author) 8 refs., 8 figs.

  13. 78 FR 39345 - ACS Wireless, Inc.; Notice of Application

    2013-07-01

    ... will transfer to AWN all remaining tangible and intangible assets owned, leased or held by ACS Wireless.... \\6\\ ACS Group will cause certain of its other subsidiaries to transfer wireless spectrum licenses and...'' as the power to exercise a controlling influence over the management or policies of a company,...

  14. Operation of AC Adapters Visualized Using Light-Emitting Diodes

    Regester, Jeffrey

    2016-01-01

    A bridge rectifier is a diamond-shaped configuration of diodes that serves to convert alternating current(AC) into direct current (DC). In our world of AC outlets and DC electronics, they are ubiquitous. Of course, most bridge rectifiers are built with regular diodes, not the light-emitting variety, because LEDs have a number of disadvantages. For…

  15. Search for β-delayed fission of 228Ac

    Radium was radiochemically separated from natural thorium. Thin 228Ra→β-228Ac sources were prepared and exposed to mica fission track detectors, and measured by an HPGe γ-ray detector. The β-delayed fission events of 228Ac were observed and its β-delayed fission probability was found to be (5±2)x10-12

  16. To Evaluate Zero Emission Propulsion and Support Technology for Transit Buses

    Kevin Chandler; Leslie Eudy

    2006-11-01

    This report provides evaluation results for prototype fuel cell transit buses operating at Santa Clara Valley Transportation Authority (VTA) in San Jose, California, in partnership with the San Mateo County Transit District in San Carlos, California. VTA has been operating three fuel cell transit buses in extra revenue service since February 28, 2005. This report provides descriptions of the equipment used, early experiences, and evaluation results from the operation of the buses and the supporting hydrogen infrastructure from March 2005 through July 2006.

  17. Energy Transitions, Economic Growth and Structural Change: Portugal in a Long-run Comparative Perspective

    Henriques, Sofia

    2011-01-01

    This book analyses, in an international comparative context, Portugal´s energy transition from organic sources to fossil fuels in the period 1856-2006. It investigates the role that energy played in the industrialization of the country and how the relationship between energy and economic growth changed with the transition from an industrial to a service society. A unique dataset of energy quantities and prices reveals that Portugal´s transition to fossil fuels and high-energy quantities wa...

  18. Improved Design Methods for Robust Single- and Three-Phase ac-dc-ac Power Converters

    Qin, Zian

    proposed new active power decoupling method, the ripple power in the converter can be compensated in a more efficient and more compact way. Then, Chapter 5 changes the scope of the thesis to three-phase converters, and the nine-switch converter, as a reduced switch version of two three-phase full......-bridges connected back-to-back, is studied. Application criteria of the nine-switch converter are investigated for reducing the relatively high stress introduced by the less number of switches. In Chapter 6 a rotating speed controller design method is proposed for improving the thermal loading of the three...... to users. Their performances including cost, efficiency, reliability, and so on, therefore are more important concerns than they were. The objective of this thesis is to study and propose advanced design methods for robust ac-dc-ac converters, which are widely used interfaces in energy conversion...

  19. 40 CFR 86.162-00 - Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2.

    2010-07-01

    ... Procedures § 86.162-00 Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2. The alternative air conditioning test procedures AC1 and AC2 are approved by the Administrator... requirements of paragraph (a) of this section and meet the requirements of § 86.163-00. Air conditioning...

  20. The modeling and simulation of thermal based modified solid oxide fuel cell (SOFC) for grid-connected systems

    Ayetül Gelen; Tankut Yalcinoz

    2015-01-01

    This paper presents a thermal based modified dynamic model of a Solid Oxide Fuel Cell (SOFC) for grid-connected systems. The proposed fuel cell model involves ohmic, activation and concentration voltage losses, thermal dynamics, methanol reformer, fuel utilization factor and power limiting module. A power conditioning unit (PCU), which consists of a DC-DC boost converter and a DC-AC voltage-source inverter (VSI), their controller, transformer and filter, is designed for grid-connected systems...

  1. High frequency link DC/AC converter using a three-phase output PWM controlled cycloconverter. Sanso shutsuryoku PWM seigyo cycloconverter wo mochiita koshuha link DC/AC converter

    Inagaki, K. (Toshiba Corp., Tokyo (Japan)); Okuma, S. (Nagoya University, Nagoya (Japan))

    1992-06-20

    The main circuit configuration and control method were proposed of the high-frequency link DC/AC converter using a three-phase output cycloconverter for UPSs (uninterruptible power supply). The control function approach of the previously proposed PWM controlled cycloconverter was applied to control of the proposed cycloconverter which converts single-phase high-frequency power into three-phase commercial frequency one. The proposed converter could not only charge DC power supplies from a power system but also compensate enough instantaneous reactive power for loads. The circuit configuration was, in particular, effective for such DC power supplies as fuel cell and solar cell which are possible to generate electric power and necessary to be insulated electrically against a power system. The isolated operation and cooperative one of the proposed DC/AC converter were verified by simulation and experiments. 4 refs., 14 figs., 1 tab.

  2. Determination for β-delayed fission probability of 230Ac

    袁双贵; 杨维凡; 徐岩冰; 肖永厚; 罗亦孝

    2002-01-01

    The 230Ra has been produced via 232Th-2p reaction induced by 60 MeV/u 18O ion irradia-tion of natural thorium. The radium was radiochemically separated from the mixture of thorium andreaction products. Thin Ra sources in which 230Ac was got through 230Ra β- → 230Ac were pre-pared for observing fission fragments from β-delayed fission of 230Ac. The sources were exposedto the mica fission track detectors and measured by the HPGe γ detector. The precursor 230Ac wasidentified by means of observed two fission events as well as γ spectra, and the β-delayed fissionprobability of 230Ac was obtained to be (1.19±0.85) × 10-8.

  3. Development of YBCO HTS cable with low AC loss

    High temperature superconducting (HTS) cables using YBCO tapes are expected to be more economical because AC losses will be much smaller than conventional cables. To reduce AC loss, 10 mm wide YBCO tapes were divided into five strips using a YAG laser. Using narrower strips and optimizing the space between the strips were effective in reducing AC loss. A 1 m conductor was fabricated, and AC loss was 0.048 W/m at 1 kA and 50 Hz. Based on the successful AC loss reduction in the 1 m conductor, we will fabricate a 10 m HTS cable with a three-layer HTS conductor, electrical insulation, and a one-layer HTS shield and cupper protection layer for overcurrent. In addition, we have developed a prototype of the HTS cable joint that can withstand an overcurrent condition of 31.5 kA for 2 s

  4. Importance of Attenuation Correction (AC) for Small Animal PET Imaging

    El Ali, Henrik H.; Bodholdt, Rasmus Poul; Jørgensen, Jesper Tranekjær;

    2012-01-01

    performed. Methods: Ten NMRI nude mice with subcutaneous implantation of human breast cancer cells (MCF-7) were scanned consecutively in small animal PET and CT scanners (MicroPETTM Focus 120 and ImTek’s MicroCATTM II). CT-based AC, PET-based AC and uniform AC methods were compared. Results: The activity...... bladder 18 ± 3% (15–21%). The FBP reconstructed images showed almost the same attenuation levels as the MAP reconstructed images for all organs. Conclusions: The annihilation photons are suffering attenuation even in small subjects. Both PET-based and CT-based are adequate as AC methods. The amplitude of...... the AC recovery could be overestimated using the uniform map. Therefore, application of a global attenuation factor on PET data might not be accurate for attenuation correction....

  5. Ac response of a coupled double quantum dot

    Xu Jie; W.Z. Shangguan; Zhan Shi-Chang

    2005-01-01

    The effect of phase-breaking process on the ac response of a coupled double quantum dot is studied in this paper based on the nonequilibrium Green function formalism. A general expression is derived for the ac current in the presence of electron-phonon interaction. The ac conductance is numerically computed and the results are compared with those in [Anatram M P and Datts S 1995 Phys. Rev. B 51 7632]. Our results reveal that the inter-dot electron tunnelling interplays with that between dots and electron reservoirs, and contributes prominently to the ac current when inter-dot tunnelling coupling is much larger than the tunnelling coupling between dots and electron reservoirs. In addition, the phase-breaking process is found to have a significant effect on the ac transport through the coupled double dot.

  6. A Simple Load Power Estimator For Quasi-Direct AC-AC Converter System

    Marian GAICEANU

    2003-12-01

    Full Text Available In this paper a simple load power estimator for the three-phase quasi-direct acac converter system is reported. Since the ac-ac converter control by means of pulsewidth modulation (PWM is based on the power balance concept, its load power should be known. Two control boards, based on the dSMC (digital Smart Motion Controller 30 MIPS 32-bit fixed-point digital signal processor (DSP, were involved in the ac-ac system driving. By using the power balance control, the DC link voltage variation at the load changes can be reduced. In this way a small DC link capacitor is required to handle the dc voltage error control. The feed-forward (Sul and Lipo, 1990 current component provides fast correction of the reference control to load power variation. In order to obtain the feed-forward current component, the load power must to be known. In this paper the load power is estimated from the dc link, indirectly, through a dc load current estimator. In this way the author overcomes the use of the serial communication between control boards (Gaiceanu, 2004 in order to deliver the load power information from the inverter side. The load current estimator is based on the DC link voltage and on the load current of the supply converter. This method presents certain advantages instead of using measured method, which requires a low pass filter: no time delay, the feed-forward current component has no ripple, no additional hardware, and more fast control response. Through simulation and experimental results the performances of the proposed load current estimator scheme are demonstrated.

  7. BWXT commercialization activities for GTRI LEU U-Mo fuels

    BWX Technologies (BWXT), the United States' research reactor fuel supplier for plate type fuel, has been contracted to provide commercialization support activities under the Global Threat Reduction Initiative (GTRI) program to develop and qualify low enrichment uranium (LEU), high density fuels suitable for most of the world's research reactors by the end of 2010. The program's main effort has been testing of uranium-molybdenum alloy fuels (U-Mo), and in light of recent fuel failures with dispersion type fuels, emphasis has now been placed on developing modified and alternative fuels. BWXT's contract scope entails identifying requirements and planning the transition to the new LEU fuels. As there is no clearly preferred fuel technology at this point, multiple commercialization paths must be evaluated. Our baseline approach assumes the fuel is monolithic U-10Mo, and the fuel meat and aluminum alloy plate are hot isostatic pressed (HIP) together. Preliminary results are supportive of this method, however, there is potential for significant interaction between the fuel meat and aluminum alloy plate during the HIP process. Alternative bonding methods, e.g. friction stir welding are being evaluated, as well as modifying the baseline HIP parameters. Additionally, modified dispersed fuel systems are considered. Aspects of each fuel technology and their manufacturing impact are presented and discussed. (author)

  8. HVDC-AC system interaction from AC harmonics. Volume 1. Harmonic impedance calculations. Final report

    Breuer, G D; Chow, J H; Lindh, C B; Miller, N W; Numrich, F H; Price, W W; Turner, A E; Whitney, R R

    1982-09-01

    Improved methods are needed to characterize ac system harmonic behavior for ac filter design for HVDC systems. The purpose of this General Electric Company RP1138 research is to evaluate the present filter design practice and to investigate methods for calculating system harmonic impedances. An overview of ac filter design for HVDC systems and a survey of literature related to filter design have been performed. Two methods for calculating system harmonic impedances have been investigated. In the measurement method, an instrumentation system for measuring system voltage and current has been assembled. Different schemes of using the measurements to calculate system harmonic impedances have been studied. In the analytical method, a procedure to include various operating conditions has been proposed. Computer programs for both methods have been prepared, and the results of the measurement and analytical methods analyzed. A conclusion of the project is that the measurement and analytical methods both provided reasonable results. There are correlations between the measured and analytical results for most harmonics, although there are discrepancies between the assumptions used in the two methods. A sensitivity approach has been proposed to further correlate the results. From the results of the analysis, it is recommended that both methods should be tested further. For the measurement method, more testing should be done to cover different system operating conditions. In the analytical method, more detailed models for representing system components should be studied. In addition, alternative statistical and sensitivity approaches should be attempted.

  9. Sustainable AC/AC hybrid electrochemical capacitors in aqueous electrolyte approaching the performance of organic systems

    Abbas, Qamar; Babuchowska, Paulina; Frąckowiak, Elżbieta; Béguin, François

    2016-09-01

    A high energy hybrid AC/AC electrochemical capacitor has been realized in aqueous Li2SO4+KI electrolyte mixture. Owing to the redox processes associated with the 2I-/I2 system, the positive electrode operates in narrow potential range and displays high capacity. During prolonged potentiostatic floating at 1.6 V, the hybrid cell demonstrates remarkably stable capacitance and resistance. Analyses by temperature programmed desorption after floating at 1.6 V proved that oxidation of the positive AC electrode is prevented by the use of Li2SO4+KI, which enables the maximum potential of this electrode to be shifted below the water oxidation potential. When charged at 0.2 A g-1 up to U = 1.6 V, the hybrid cell displays a high capacitance of 75 F g-1 (300 F g-1 per mass of one electrode) compared to 47 F g-1 (188 F g-1 per mass of one electrode) for a symmetric cell in Li2SO4. At 0.2 A g-1 up to 1.6 V, the hybrid capacitor in Li2SO4+KI displays an energy density of 26 Wh kg-1 which approaches the energy density of 30.9 Wh kg-1 measured when the same carbon is implemented in a capacitor using TEABF4/ACN electrolyte and charged up to 2.5 V.

  10. ESBWR response to an extended station blackout/loss of all AC power

    U.S. federal regulations require light water cooled nuclear power plants to cope with Station Blackouts for a predetermined amount of time based on design factors for the plant. U.S. regulations define Station Blackout (SBO) as a loss of the offsite electric power system concurrent with turbine trip and unavailability of the onsite emergency AC power system. According to U.S. regulations, typically the coping period for an SBO is 4 hours and can be as long as 16 hours for currently operating BWR plants. Being able to cope with an SBO and loss of all AC power is required by international regulators as well. The U.S. licensing basis for the ESBWR is a coping period of 72 hours for an SBO based on U.S. NRC requirements for passive safety plants. In the event of an extended SBO (viz., greater than 72 hours), the ESBWR response shows that the design is able to cope with the event for at least 7 days without AC electrical power or operator action. ESBWR is a Generation III+ reactor design with an array of passive safety systems. The ESBWR primary success path for mitigation of an SBO event is the Isolation Condenser System (ICS). The ICS is a passive, closed loop, safety system that initiates automatically on a loss of power. Upon Station Blackout or loss of all AC power, the ICS begins removing decay heat from the Reactor Pressure Vessel (RPV) by (i) condensing the steam into water in heat exchangers located in pools of water above the containment, and (ii) transferring the decay heat to the atmosphere. The condensed water is then returned by gravity to cool the reactor again. The ICS alone is capable of maintaining the ESBWR in a safe shutdown condition after an SBO for an extended period. The fuel remains covered throughout the SBO event. The ICS is able to remove decay heat from the RPV for at least 7 days and maintains the reactor in a safe shutdown condition. The water level in the RPV remains well above the top of active fuel for the duration of the SBO event

  11. Safe-commutation principle for direct single-phase AC-AC converters for use in audio power amplification

    Ljusev, Petar; Andersen, Michael Andreas E.

    2004-01-01

    This paper presents an alternative safe commutation principle for a single phase bidirectional bridge, for use in the new generation of direct single-stage AC-AC audio power amplifiers. As compared with the bridge commutation with load current or source voltage sensing, in this approach it is not...

  12. La acústica submarina y su desarrollo desde la creación del Instituto de Acústica

    Ranz Guerra, Carlos; Cobo, Pedro; Carbó, Rafael; Santiago Páez, José Salvador; Soler, A. M.; Briones, J. M.; Jimeno, I.; Muñoz, N; Camarasa, M.; Recuero López, Manuel

    2000-01-01

    PACS: 43.30.Xm; 43.30.Yj; 43.30.Vh; 43.30.Nb; 43.30.Ma.-- Publicado en el Vol. XXXI, núm. 3-4, tercer y cuarto trimestre 2000 de la Revista de Acústica: Número especial dedicado al XXV Aniversario del Instituto de Acústica del C.S.I.C.

  13. Variable valve actuation and dual-fuel combustion

    Törmänen, Juhani

    2015-01-01

    The constantly increasing interest in alternative fuels in transportation has given birth to new strategies in the internal combustion engine technology. The tightening emissions regulations further boost this development. The dual-fuel technology is one of the most promising new concepts for natural gas-fuelled engines and it has already been widely adopted by the marine and power generation industry. However, the transition from Diesel to dual-fuel engines in road and off-road traffic has n...

  14. LMFBR fuel component costs

    A significant portion of the cost of fabricating LMFBR fuels is in the non-fuel components such as fuel pin cladding, fuel assembly ducts and end fittings. The contribution of these to fuel fabrication costs, based on FFTF experience and extrapolated to large LMFBR fuel loadings, is discussed. The extrapolation considers the expected effects of LMFBR development programs in progress on non-fuel component costs

  15. Synthetic and Biomass Alternate Fueling in Aviation

    Hendricks, Robert C.; Bushnell, Dennis M.

    2009-01-01

    Must use earth's most abundant natural resources - Biomass, Solar, Arid land (43%), Seawater (97%) with nutrients (80%) plus brackish waters and nutrients resolve environmental triangle of conflicts energy-food-freshwater and ultrafine particulate hazards. Requires Paradigm Shift - Develop and Use Solar* for energy; Biomass for aviation and hybrid-electric-compressed air mobility fueling with transition to hydrogen long term.

  16. Thermophysical properties of fast reactor fuel

    This paper identifies the fuel properties for which more data are needed for fast-reactor safety analysis. In addition, a brief review is given of current research on the vapor pressure over liquid UO2 and (U,PU)O/sub 2-x/, the solid-solid phase transition in actinide oxides, and the thermal conductivity of molten urania

  17. Design study and evaluation of advanced fuel fabrication systems for FBR fuel cycle

    The conceptual design study for advanced FBR fuel fabrication system has been performed for the purpose that the feature of small-scale fabrication system in the transition stage from LWR to FBR fuel cycle. On the small-scale of 50 ton heavy metal per year fabrication system, dry type fabrication systems have superior cost performance than the wet type, although waste amount is larger. (authors)

  18. Numerical estimation of AC loss in superconductors with ripple current

    Highlights: •The loss energy density with ripple current is numerically calculated. •Irie–Yamafuji model is used for magnetic field dependence of critical current. •Calculated result of cylindrical superconductor agrees with theoretical result. •AC loss of strip superconductor becomes large at small ripple current amplitude. •Strip superconductor should be used as a form of hollow cylinder to reduce AC loss. -- Abstract: The loss energy density (AC loss) with ripple current is numerically calculated by finite element method for cylindrical and strip superconductors based on Irie–Yamafuji model in which the magnetic field dependence of the critical current density is taken into account for design of DC transmission cable system. It is confirmed that calculated result of the AC loss in the cylindrical superconductor with the ripple current agrees well with theoretical estimation which was reported in the previous work. On the contrary, the AC loss in the strip superconductor with the ripple current is obtained only by numerical calculation. It is found that the AC loss in the strip superconductor of the ripple current becomes larger than that without DC current at small ripple current amplitude, since the penetration depth of magnetic field becomes large. Therefore, it is recommended that strip superconductor is better to use as cylindrical hollow superconductor for DC transmission cable system to reduce the AC loss

  19. Importance of Attenuation Correction (AC for Small Animal PET Imaging

    Henrik H. El Ali

    2012-10-01

    Full Text Available The purpose of this study was to investigate whether a correction for annihilation photon attenuation in small objects such as mice is necessary. The attenuation recovery for specific organs and subcutaneous tumors was investigated. A comparison between different attenuation correction methods was performed. Methods: Ten NMRI nude mice with subcutaneous implantation of human breast cancer cells (MCF-7 were scanned consecutively in small animal PET and CT scanners (MicroPETTM Focus 120 and ImTek’s MicroCATTM II. CT-based AC, PET-based AC and uniform AC methods were compared. Results: The activity concentration in the same organ with and without AC revealed an overall attenuation recovery of 9–21% for MAP reconstructed images, i.e., SUV without AC could underestimate the true activity at this level. For subcutaneous tumors, the attenuation was 13 ± 4% (9–17%, for kidneys 20 ± 1% (19–21%, and for bladder 18 ± 3% (15–21%. The FBP reconstructed images showed almost the same attenuation levels as the MAP reconstructed images for all organs. Conclusions: The annihilation photons are suffering attenuation even in small subjects. Both PET-based and CT-based are adequate as AC methods. The amplitude of the AC recovery could be overestimated using the uniform map. Therefore, application of a global attenuation factor on PET data might not be accurate for attenuation correction.

  20. Analytical description of AC losses for high temperature superconductors

    Full text: AC losses for high temperature superconductors have been calculated by considering the effects of the temperature distribution and the flux flow resistance. Maxwell's equations and thermal diffusion equation are used to calculate the distribution of magnetic field and the temperature inside the superconductors, respectively. The flux flow effect on the AC losses is calculated by using the extended critical state model. An analytical expression of the AC losses is obtained using a superposition approximation in which the cases of complete and incomplete magnetic field penetration have been distinguished. The expression can well explain the experimental observations of the frequency dependence of the AC losses per cycle in high temperature superconductors. It is clearly shown from the analytical expression that the effect of the thermal distribution inside the superconductors is different from the effect caused by flux flow resistance. In the case of incomplete magnetic penetration, the temperature distribution results in the increase of the AC losses per cycle upon frequency whereas the flux flow leads to the decrease of the AC losses per cycle upon frequency. In the case of complete magnetic penetration the results are opposite to those in the previous case. Due to the extremely strong flux flow in high temperature superconducting materials, the effect of the flux flow on the AC losses is dominant, and the overall dependence of AC losses per cycle upon frequency is controlled by the flux flow. On the other hand, because the inhomogeneous distribution of the temperature inside the superconductors which is normal higher in the center than near the edge, there is an upper limit for the frequency beyond which the superconductivity will be totally destroyed by AC losses. Analytical expressions for the critical frequency, distributions of magnetic field and critical current density are also obtained

  1. Sustainability of Fossil Fuels

    Lackner, K. S.

    2002-05-01

    For a sustainable world economy, energy is a bottleneck. Energy is at the basis of a modern, technological society, but unlike materials it cannot be recycled. Energy or more precisely "negentropy" (the opposite of entropy) is always consumed. Thus, one either accepts the use of large but finite resources or must stay within the limits imposed by dilute but self-renewing resources like sunlight. The challenge of sustainable energy is exacerbated by likely growth in world energy demand due to increased population and increased wealth. Most of the world still has to undergo the transition to a wealthy, stable society with the near zero population growth that characterizes a modern industrial society. This represents a huge unmet demand. If ten billion people were to consume energy like North Americans do today, world energy demand would be ten times higher. In addition, technological advances while often improving energy efficiency tend to raise energy demand by offering more opportunity for consumption. Energy consumption still increases at close to the 2.3% per year that would lead to a tenfold increase over the course of the next century. Meeting future energy demands while phasing out fossil fuels appears extremely difficult. Instead, the world needs sustainable or nearly sustainable fossil fuels. I propose the following definition of sustainable under which fossil fuels would well qualify: The use of a technology or resource is sustainable if the intended and unintended consequences will not force its abandonment within a reasonable planning horizon. Of course sustainable technologies must not be limited by resource depletion but this is only one of many concerns. Environmental impacts, excessive land use, and other constraints can equally limit the use of a technology and thus render it unsustainable. In the foreseeable future, fossil fuels are not limited by resource depletion. However, environmental concerns based on climate change and other environmental

  2. Gifts from Exoplanetary Transits

    Narita, Norio

    2009-01-01

    The discovery of transiting extrasolar planets has enabled us a number of interesting stduies. Transit photometry reveals the radius and the orbital inclination of transiting planets, and thereby we can learn the true mass and the density of respective planets by the combined information of radial velocity measurements. In addition, follow-up observations of transiting planets such as secondary eclipse, transit timing variations, transmission spectroscopy, and the Rossiter-McLaughlin effect p...

  3. Terminology used for renewable liquid and gaseous fuels based on the conversion of electricity: a review

    Ridjan, Iva; Mathiesen, Brian Vad; Connolly, David

    2016-01-01

    As the transport sector transitions away from fossil fuels and renewable fuels shift into focus, it is important that the terminology around renewable fuels is clarified. A number of terms such as synthetic fuel and electrofuel are used to describe both renewable and alternative fuels. The aim of...... results confirm that the term synthetic fuel is used generically in the majority of articles, without providing information about the production process of the fuel or differentiating between fossil-based and renewable-based synthetic fuels. The majority of the articles use the term synthetic fuel to...... describe fuels produced with coal-, gas- and biomass-to-liquid (xTL) technologies. However, a number of articles use the term beyond this definition. Results for the term electrofuel gave a similar outcome, as it was not clear which processes were used for the fuel production. In some cases, both synthetic...

  4. Characterization of the 309 building fuel transfer pit and storage basin

    This document identifies radiological, chemical and physical conditions inside the Fuel Transfer Pit and Fuel Storage Basins. These spaces are located inside the Plutonium Recycle Test Reactor structure (309 Building.) The fuel handling and storage feature of the PRTR were primarily located in these spaces. The conditions were assessed as part of overall 309 Building transition

  5. High performance, high durability non-precious metal fuel cell catalysts

    Wood, Thomas E.; Atanasoski, Radoslav; Schmoeckel, Alison K.

    2016-03-15

    This invention relates to non-precious metal fuel cell cathode catalysts, fuel cells that contain these catalysts, and methods of making the same. The fuel cell cathode catalysts are highly nitrogenated carbon materials that can contain a transition metal. The highly nitrogenated carbon materials can be supported on a nanoparticle substrate.

  6. Consolidated Fuel Reprocessing Program. Progress report, January 1 to March 31, 1979

    Unger, W.E. (comp.)

    1979-06-01

    On Oct. 1, 1978, a transition phase was begun to concentrate all US fuel reprocessing research in one major program, the Consolidated Fuel Reprocessing Program (CFRP). The CFRP is organized into the following: process R and D, engineering research, engineering systems, technical support, HTGR fuel reprocessing, and pyrochemical and dry processing methods. Progress is reported in each area. (DLC)

  7. Fuel-cycle costs for alternative fuels

    This paper compares the fuel cycle cost and fresh fuel requirements for a range of nuclear reactor systems including the present day LWR without fuel recycle, an LWR modified to obtain a higher fuel burnup, an LWR using recycle uranium and plutonium fuel, an LWR using a proliferation resistant 233U-Th cycle, a heavy water reactor, a couple of HTGRs, a GCFR, and several LMFBRs. These reactor systems were selected from a set of 26 developed for the NASAP study and represent a wide range of fuel cycle requirements

  8. Operation of AC Adapters Visualized Using Light-Emitting Diodes

    Regester, Jeffrey

    2016-01-01

    A bridge rectifier is a diamond-shaped configuration of diodes that serves to convert alternating current (AC) into direct current (DC). In our world of AC outlets and DC electronics, they are ubiquitous. Of course, most bridge rectifiers are built with regular diodes, not the light-emitting variety, because LEDs have a number of disadvantages. For educational purposes, however, an LED-based rectifier is ideal because it allows students to literally see the rectifier operating. Here I'll discuss the practical aspects of building a full AC adapter incorporating an LED-based rectifier and ideas on how to use it in class.

  9. Theoretical analysis of ac losses in high temperature superconducting bulks

    Ac loss behavior in HTS bulk materials is studied by developing an analytic method. The self-heating effect on the distributions of temperature in HTS bulks has been calculated. A critical frequency which sets the upper limit for driving frequency of the external field in sustaining a superconducting state is obtained. Our model provides useful information of understanding the experimental phenomena, including an anomalous ac loss behavior, a retardation of the inner field respect to the external ac field, etc., in HTS bulk materials

  10. Advanced DC/AC inverters applications in renewable energy

    Luo, Fang Lin

    2013-01-01

    DC/AC inversion technology is of vital importance for industrial applications, including electrical vehicles and renewable energy systems, which require a large number of inverters. In recent years, inversion technology has developed rapidly, with new topologies improving the power factor and increasing power efficiency. Proposing many novel approaches, Advanced DC/AC Inverters: Applications in Renewable Energy describes advanced DC/AC inverters that can be used for renewable energy systems. The book introduces more than 100 topologies of advanced inverters originally developed by the authors,

  11. Analysis of Input and Output Ripples of PWM AC Choppers

    Pekik Argo Dahono

    2008-11-01

    Full Text Available This paper presents an analysis of input and output ripples of PWM AC choppers. Expressions of input and output current and voltage ripples of single-phase PWM AC choppers are first derived. The derived expressions are then extended to three-phase PWM AC choppers. As input current and output voltage ripples specification alone cannot be used to determine the unique values of inductance and capacitance of the LC filters, an additional criterion based on the minimum reactive power is proposed. Experimental results are included in this paper to show the validity of the proposed analysis method.

  12. An Improved AC-BM Algorithm for Monitoring Watch List

    Mo Yiwen

    2013-07-01

    Full Text Available With the expanding of database of the watch list of anti-money laundering, improving the speed in matching between the watch list and the database of account holders and clients’ transaction is especially important. This paper proposes an improved AC-BM Algorithm, a matching algorithm of subsection, to improve the speed of matching. Experiment results show the time performance of the improved algorithm is better than traditional BM algorithm, AC algorithm and the AC-BM algorithm. It can improve the efficiency of on-line monitoring of anti-money laundering.  

  13. Study on radioimmunoassay of Bt Cry1Ac protein

    Bt Cry1Ac protein was extracted from incubation of Bacillus thuringiensis HD-73, and cutting into more specific protein segment with high insect-resistance. High-affinity multi-colonial antibodies of Bt Cry1 Ac protein were obtained after injected it into New Zealand rabbits. By 125I labeling of Bt Cry1 Ac protein, a RIA kit was established. In this method, centrifuge for separation was not necessary due to the use of magnetic micro-particle and the specifications of the kit were found equal to those of imported ELISA. (authors)

  14. Stochastic Dynamics of DC and AC Driven Dislocation Kinks

    Vardanyan, A.; Kteyan, A.

    2013-02-01

    Dynamics of a pinned dislocation kink controlled by the acting DC and AC forces is studied analytically. The motion of the kink, described by sine-Gordon (sG) equation, is explored within the framework of McLaughlin-Scott perturbation theory. Assuming weakness of the acting AC force, the equation of motion of the dislocation kink in the pinning potential is linearized. Based on the equations derived, we study stochastic behavior of the kink, and determine the probability of its depinning. The dependencies of the depinning probability on DC and AC forces are analyzed in detail.

  15. Observation of β-delayed fission from 230Ac

    β-delayed fission for 230Ac was searched. 230Ra was produced via multinucleon transfer reaction by 60 MeV/u 18O ion irradiation of 232Th target. Thin 230Ra→230Ac sources of 108 atoms were acquired through radiochemical separations. The mica track detectors were used to record the fission events. The β-delayed fission nucleus 230Ac was identified via the observed two fission events and the measured γ-ray spectra. Its β-delayed fission probability was obtained to be (1.19 +- 0.85) x 10-8

  16. Dynamic Simulations of Advanced Fuel Cycles

    Steven J. Piet; Brent W. Dixon; Jacob J. Jacobson; Gretchen E. Matthern; David E. Shropshire

    2011-03-01

    Years of performing dynamic simulations of advanced nuclear fuel cycle options provide insights into how they could work and how one might transition from the current once-through fuel cycle. This paper summarizes those insights from the context of the 2005 objectives and goals of the U.S. Advanced Fuel Cycle Initiative (AFCI). Our intent is not to compare options, assess options versus those objectives and goals, nor recommend changes to those objectives and goals. Rather, we organize what we have learned from dynamic simulations in the context of the AFCI objectives for waste management, proliferation resistance, uranium utilization, and economics. Thus, we do not merely describe “lessons learned” from dynamic simulations but attempt to answer the “so what” question by using this context. The analyses have been performed using the Verifiable Fuel Cycle Simulation of Nuclear Fuel Cycle Dynamics (VISION). We observe that the 2005 objectives and goals do not address many of the inherently dynamic discriminators among advanced fuel cycle options and transitions thereof.

  17. Spectroscopy of nuclei 215Fr and 219 Ac: a contribution to the study of the nuclear structure of light actinides

    Using α-particle and γ-ray spectroscopy, it has been possible to establish the high spin pattern in 215Fr and propose a decay scheme up to Iπ = (47/2+) containing six isomeric states. These results are interpreted using the recent version of the deformed Woods-Saxon model and the Strutinsky normalisation technique. A similar study in 219 Ac has revealed the existence of two quasi-bands each formed of states of alternating parity and connected by strong E1 transitions. This data for 219Ac fits better with the stable octupole deformation model, mainly because of the high-spin parity doublets observed for the first time, than with the α-cluster model

  18. The investigation of the decay of the deformed 167Yb, 164Tm, 225Ac, 221Fr nuclei. Beta-spectrograph with positional-sensitive detector

    The decay of the deformed 167Yb, 164Tm, 225Ac,221Fr nuclei is investigated in this work. For 167Yb and 164Tm decays the specters of the conversion electrons were measured. 32 γ-transitions were found for 167 Yb decay, 6 of which were found for the first time. The multipolarities for 9 γ-transitions were found. For 164Tm decay 23 new γ-transitions were found. The theoretical investigations of the collective states in the nucleus were carried out. Octupole-rotatory line with k=1- was found in the measurement of conversion electrons specters of the short-life nuclei. Device' nonlinearity was 0,04%. Resolution was Δβρ/βρ 0,11%. Effective light yield was 1-2 %. The decay of 225Ac and 221Fr nuclei were investigated. The investigations of α-γ -coincidence, α-γ - rays were carried out. 24 new γ -transitions for 225Ac and 13 ones for 221Fr were found. The new levels and their intensities were defined more precisely. Intensity balance calculations were carried out and the full populations of the nuclear levels were calculated. (author). 3 tabs.; 10 figs

  19. Enhanced Oxygen and Hydroxide Transport in a Cathode Interface by Efficient Antibacterial Property of a Silver Nanoparticle-Modified, Activated Carbon Cathode in Microbial Fuel Cells.

    Li, Da; Qu, Youpeng; Liu, Jia; Liu, Guohong; Zhang, Jie; Feng, Yujie

    2016-08-17

    A biofilm growing on an air cathode is responsible for the decreased performance of microbial fuel cells (MFCs). For the undesired biofilm to be minimized, silver nanoparticles were synthesized on activated carbon as the cathodic catalyst (Ag/AC) in MFCs. Ag/AC enhanced maximum power density by 14.6% compared to that of a bare activated carbon cathode (AC) due to the additional silver catalysis. After operating MFCs over five months, protein content on the Ag/AC cathode was only 38.3% of that on the AC cathode, which resulted in a higher oxygen concentration diffusing through the Ag/AC cathode. In addition, a lower pH increment (0.2 units) was obtained near the Ag/AC catalyst surface after biofouling compared to 0.8 units of the AC cathode, indicating that less biofilm on the Ag/AC cathode had a minor resistance on hydroxide transported from the catalyst layer interfaces to the bulk solution. Therefore, less decrements of the Ag/AC activity and MFC performance were obtained. This result indicated that accelerated transport of oxygen and hydroxide, benefitting from the antibacterial property of the cathode, could efficiently maintain higher cathode stability during long-term operation. PMID:27441786

  20. Cryogenic fuel tank

    A fuel tank is provided for the automotive transport of a cryogenic liquid fuel which in the course of transport is being consumed by an engine or the like. The fuel tank consists essentially of two containers, one for the cryogenic fuel and the other for a secondary cryogenic liquid which is used to cool the fuel during storage when no fuel is being consumed. By the method of the invention the build up of fuel vapor pressure during storage is avoided and the vapor pressure maintained at a predetermined level. The fuel tank described herein was two distinct modes of operation, namely, the fuel storage mode and the fuel supply mode. In the fuel storage mode the cryogenic fuel is being stored for later use while the secondary fluid is being used as a heat sink for the heat absorbed by the tank from the environment. In the fuel supply mode fuel is being supplied by the tank for consumption both as a liquid and as a gas while the secondary fluid is being restored to its initial state of lower temperature by the use of a refrigerator which employs the fuel as a heat sink. The two containers are thermally insulated from the outside environment as well as from each other. The fuel container and the secondary fluid container are connected by a heat transfer bridge which permits heat flow from the fuel to the secondary fluid only during the storage mode of operation. The fuel container has two fuel discharge connections, one carrying the liquid fuel the other carrying gaseous fuel which is vaporized within the fuel container. The pressure in the fuel container is maintained at an adequate level for the fuel supply to proceed without the need for a fuel pump

  1. Neurinoma central do nervo acústico

    Paulo Pinto Pupo

    1950-03-01

    Full Text Available O autor apresenta o caso de uma paciente com 45 anos, com hipertensão arterial, queixando-se de tonturas e surdez progressiva à esquerda que, ao exame neurológico, apresentava síndrome protuberancial, com hemi-anestesia táctil e dolorosa à direita respeitando a face, hemiparesia direita, ataxia de tipo sensitivo nos membros da direita, paralisia facial de tipo periférico, hipoacusia, paresia de motor ocular externo à esquerda, síndrome vertiginosa e nistagmo horizontal ao olhar para a direita. À necrópsia foi encontrado um tumor na hemicalota protuberancial esquerda e foco malácico adjacente, secundário a distúrbio circulatório. O tumor, intimamente dependente das raízes intraprotuberanciais do nervo acústico, se apresentava com as características histológicas dos neurinomas. Além dessas particularidades, a lesão do feixe central da calota e conseqüente degeneração "hipertrófica" da oliva bulbar constituem outro aspecto de grande interêsse dêste caso.

  2. AC Impedance Behaviour of Black Diamond Films

    Haitao YE; Olivier GAUDIN; Richard B.JACKMAN

    2005-01-01

    The first measurement of impedance on free-standing diamond films from 0.1 Hz to 10 MHz up to 300℃ were reported. A wide range of chemical vapour deposition (CVD) materials were investigated, but here we concentrate are well fitted to a RC parallel circuit model and the equivalent resistance and capacitance for the diamond films have been estimated using the Zview curve fitting. The results show only one single semicircle response at each temperature measured. It was found that the resistance decreases from 62 MΩ at room temperature to 4 kΩ at300℃, with an activation energy around 0.51 eV. The equivalent capacitance is maintained at the level of 100 pF up to 300℃ suggesting that the diamond grain boundaries are dominating the conduction. At 400℃, the impedance at low frequencies shows a linear tail, which can be explained that the AC polarization of diamond/Au interface occurs.

  3. Property Rights, Institutions and Source of Fuel Wood in Rural Ethiopia

    Abebe Damte; Steven F. Koc

    2011-01-01

    This study examines the relationship between property rights, defined by land tenure security and the strength of local-level institutions, and household demand for fuel wood, as measured by the source from which fuel wood is collected. A multinomial regression model is applied to survey data collected in rural Ethiopia. Results from the discrete choice model indicate that active local-level institutions increase household dependency on open access forests, while land security reduces open ac...

  4. Dicty_cDB: FCL-AC22 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC22 (Link to dictyBase) - G03266 DDB0186811 Contig-U14995-1 FCL-...AC22P (Link to Original site) FCL-AC22F 430 FCL-AC22Z 521 FCL-AC22P 951 - - Show FCL-AC22 Library FC...L (Link to library) Clone ID FCL-AC22 (Link to dictyBase) Atlas ID - NBRP ID G03266 dictyBase ID DDB0186811 ...Link to Contig Contig-U14995-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-...AC22Q.Seq.d/ Representative seq. ID FCL-AC22P (Link to Original site) Representative DNA sequence >FCL-

  5. Dicty_cDB: FCL-AC23 [Dicty_cDB

    Full Text Available FCL (Link to library) FCL-AC23 (Link to dictyBase) - G01760 DDB0186002 Contig-U16043-1 FCL-...AC23P (Link to Original site) FCL-AC23F 132 FCL-AC23Z 582 FCL-AC23P 714 - - Show FCL-AC23 Library FC...L (Link to library) Clone ID FCL-AC23 (Link to dictyBase) Atlas ID - NBRP ID G01760 dictyBase ID DDB0186002 ...Link to Contig Contig-U16043-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FCL/FCL-AC/FCL-...AC23Q.Seq.d/ Representative seq. ID FCL-AC23P (Link to Original site) Representative DNA sequence >FCL-

  6. Fuel processors for fuel cell APU applications

    Aicher, T.; Lenz, B.; Gschnell, F.; Groos, U.; Federici, F.; Caprile, L.; Parodi, L.

    The conversion of liquid hydrocarbons to a hydrogen rich product gas is a central process step in fuel processors for auxiliary power units (APUs) for vehicles of all kinds. The selection of the reforming process depends on the fuel and the type of the fuel cell. For vehicle power trains, liquid hydrocarbons like gasoline, kerosene, and diesel are utilized and, therefore, they will also be the fuel for the respective APU systems. The fuel cells commonly envisioned for mobile APU applications are molten carbonate fuel cells (MCFC), solid oxide fuel cells (SOFC), and proton exchange membrane fuel cells (PEMFC). Since high-temperature fuel cells, e.g. MCFCs or SOFCs, can be supplied with a feed gas that contains carbon monoxide (CO) their fuel processor does not require reactors for CO reduction and removal. For PEMFCs on the other hand, CO concentrations in the feed gas must not exceed 50 ppm, better 20 ppm, which requires additional reactors downstream of the reforming reactor. This paper gives an overview of the current state of the fuel processor development for APU applications and APU system developments. Furthermore, it will present the latest developments at Fraunhofer ISE regarding fuel processors for high-temperature fuel cell APU systems on board of ships and aircrafts.

  7. Highly sensitive pseudo-differential ac-nanocalorimeter for the study of the glass transition

    Laarraj, Mohcine [Institut NÉEL, CNRS, 25 Avenue des Martyrs, F-38042 Grenoble (France); University Grenoble Alpes, Institut NEEL, F-38042 Grenoble (France); Laboratoire d’Ingénierie et des Matériaux (LIMAT), Université Hassan II de Casablanca, Faculté des Sciences Ben M’Sik, Casablanca Maroc (Morocco); Adhiri, Rahma; Moussetad, Mohamed [Laboratoire d’Ingénierie et des Matériaux (LIMAT), Université Hassan II de Casablanca, Faculté des Sciences Ben M’Sik, Casablanca Maroc (Morocco); Ouaskit, Said [Laboratoire de Physique de la Matière Condensée (LPMC), Université Hassan II de Casablanca, Faculté des Sciences Ben M’Sik, Casablanca Maroc (Morocco); Guttin, Christophe; Richard, Jacques; Garden, Jean-Luc [Institut NÉEL, CNRS, 25 Avenue des Martyrs, F-38042 Grenoble (France); University Grenoble Alpes, Institut NEEL, F-38042 Grenoble (France)

    2015-11-15

    We present a nanocalorimeter designed for the measurement of the dynamic heat capacity of thin films. The microfabricated sensor, the thermal conditioning of the sensor, as well as the highly stable and low noise electronic chain allow measurements of the real and imaginary parts of the complex specific heat with a resolution Δ C/C of about 10{sup −5}. The performances of this quasi-differential nanocalorimeter were tested on a model of polymeric glass-former, the polyvinyl acetate (PVAc). The high stability and low noise of the device are essential for accurate studies on non-equilibrium slow relaxing systems such as glasses.

  8. Comparison of the Accuracy and Speed of Transient Mobile A/C System Simulation Models: Preprint

    Kiss, T.; Lustbader, J.

    2014-03-01

    The operation of air conditioning (A/C) systems is a significant contributor to the total amount of fuel used by light- and heavy-duty vehicles. Therefore, continued improvement of the efficiency of these mobile A/C systems is important. Numerical simulation has been used to reduce the system development time and to improve the electronic controls, but numerical models that include highly detailed physics run slower than desired for carrying out vehicle-focused drive cycle-based system optimization. Therefore, faster models are needed even if some accuracy is sacrificed. In this study, a validated model with highly detailed physics, the 'Fully-Detailed' model, and two models with different levels of simplification, the 'Quasi-Transient' and the 'Mapped- Component' models, are compared. The Quasi-Transient model applies some simplifications compared to the Fully-Detailed model to allow faster model execution speeds. The Mapped-Component model is similar to the Quasi-Transient model except instead of detailed flow and heat transfer calculations in the heat exchangers, it uses lookup tables created with the Quasi-Transient model. All three models are set up to represent the same physical A/C system and the same electronic controls. Speed and results of the three model versions are compared for steady state and transient operation. Steady state simulated data are also compared to measured data. The results show that the Quasi-Transient and Mapped-Component models ran much faster than the Fully-Detailed model, on the order of 10- and 100-fold, respectively. They also adequately approach the results of the Fully-Detailed model for steady-state operation, and for drive cycle-based efficiency predictions

  9. Nuclear reactor fuel elements

    An improved nuclear power reactor fuel element is described which consists of fuel rods, rod guide tubes and an end plate. The system allows direct access to an end of each fuel rod for inspection purposes. (U.K.)

  10. GSPEL - Fuel Cell Laboratory

    Federal Laboratory Consortium — The Fuel Cell Lab (FCL) Provides testing for technology readiness of fuel cell systems The FCL investigates, tests and verifies the performance of fuel-cell systems...

  11. KMRR fuel design

    KMRR fuel rod design criteria on fuel swelling, blistering and oxide spallation have been reexamined. Fuel centerline temperature limit of 250deg C in normal operation condition and fuel swelling limit of 12 % at the end of life have been proposed to prevent fuel failure due to excessive fuel swelling. Fuel temperature limit of 485deg C has been proposed to exclude the possibility of fuel failures during transients or under accident condition. Further analyses are needed to decide the fuel cladding temperature limit to preclude the oxide spallation. Design changes in fuel assembly structure and their effects on related systems have been reviewed from a structural integrity viewpoint. The remained works in fuel mechanical design area have been identified and further efforts of fuel design group will be focused on these aspects. (Author)

  12. Absorption and Attenuation Coefficients Using the WET Labs ac-s in the Mid-Atlantic Bight: Field Measurements and Data Analysis

    Ohi, Nobuaki; Makinen, Carla P.; Mitchell, Richard; Moisan, Tiffany A.

    2008-01-01

    Ocean color algorithms are based on the parameterization of apparent optical properties as a function of inherent optical properties. WET Labs underwater absorption and attenuation meters (ac-9 and ac-s) measure both the spectral beam attenuation [c (lambda)] and absorption coefficient [a (lambda)]. The ac-s reports in a continuous range of 390-750 nm with a band pass of 4 nm, totaling approximately 83 distinct wavelengths, while the ac-9 reports at 9 wavelengths. We performed the ac-s field measurements at nine stations in the Mid-Atlantic Bight from water calibrations to data analysis. Onboard the ship, the ac-s was calibrated daily using Milli Q-water. Corrections for the in situ temperature and salinity effects on optical properties of water were applied. Corrections for incomplete recovery of the scattered light in the ac-s absorption tube were performed. The fine scale of spectral and vertical distributions of c (lambda) and a (lambda) were described from the ac-s. The significant relationships between a (674) and that of spectrophotometric analysis and chlorophyll a concentration of discrete water samples were observed.

  13. Elements of nuclear reactor fueling theory

    Starting with a review of the simple batch size effect, a more general theory of nuclear fueling is derived to describe the behaviour and physical requirements of operating cycle sequences and fueling strategies having practical use in fuel management. The generalized theory, based on linear reactivity modeling, is analytical and represents the effects of multiple-stream, multiple-depletion-batch fueling configurations in systems employing arbitrary, non-integer batch size strategies, and containing fuel with variable energy generation rates. Reactor operating cycles and cycle sequences are represented with realistic structure that includes the effects of variable cycle energy production, cycle lengths, end-of-cycle operating extensions and manoeuvering allowances. Results of the analytical theory are first applied to the special case of degenerate equilibrium cycle sequences, yielding several fundamental principles related to the selection of refueling strategy. Numerical evaluations of degenerate equilibrium cycle sequences are then performed for a typical PWR core, and accompanying fuel cycle costs are calculated. The impact of design and operational limits as constraints on the performance mappings for this reactor are also studied with respect to achieving improved cost performance from the once-through fuel cycle. The dynamics of transition cycle sequences are then examined using the generalized theory. Proof of the existence of non-degenerate equilibrium cycle sequences is presented when the mechanics of the fixed reload batch size strategy are developed analytically for transition sequences. Finally, an analysis of the fixed reload enrichment strategy demonstrates the potential for convergence of the transition sequence to a fully degenerate equilibrium sequence. (author)

  14. Power generation using an activated carbon and metal mesh cathode in a microbial fuel cell

    Zhang, Fang

    2009-11-01

    An inexpensive activated carbon (AC) air cathode was developed as an alternative to a platinum-catalyzed electrode for oxygen reduction in a microbial fuel cell (MFC). AC was cold-pressed with a polytetrafluoroethylene (PTFE) binder to form the cathode around a Ni mesh current collector. This cathode construction avoided the need for carbon cloth or a metal catalyst, and produced a cathode with high activity for oxygen reduction at typical MFC current densities. Tests with the AC cathode produced a maximum power density of 1220 mW/m2 (normalized to cathode projected surface area; 36 W/m3 based on liquid volume) compared to 1060 mW/m2 obtained by Pt catalyzed carbon cloth cathode. The Coulombic efficiency ranged from 15% to 55%. These findings show that AC is a cost-effective material for achieving useful rates of oxygen reduction in air cathode MFCs. © 2009 Elsevier B.V. All rights reserved.

  15. How can we ensure the energy transition? Comment assurer la transition energetique?

    Rojey, Alexandre

    2007-07-01

    With a continuously growing energy demand, the present energy model is clearly unsustainable due to the decline of fossil fuel resources and the risks of climate change A transition towards a sustainable model is therefore needed. However, there are no immediate alternatives leading to a sharp reduction in the use of fossil fuels, which are expected to maintain a major role for many years. The energy transition will therefore require a long time period The risks of climate change will require urgent measures and the 'carbon transition' has to be achieved more rapidly than the energy transition itself. A whole set of solutions will be needed in the technical but also economic and regulatory areas, for achieving a successful transition: energy conservation, diversification of energy . sources, reduction of the carbon content of the energy mix, CO{sub 2}, capture and storage. Hybrid options will be favoured. The paper describes the main features of the upcoming transition and the actions which are required. (auth)

  16. Magic wavelengths for the 5s-18s transition in rubidium

    Goldschmidt, E.A.; Norris, D.G.; Koller, S.B.; Wyllie, R.; Brown, R.C.; Porto, J.; Safronova, M.S.; Safronova, U.I.

    2015-01-01

    Magic wavelengths, for which there is no differential ac Stark shift for the ground and excited state of the atom, allow trapping of excited Rydberg atoms without broadening the optical transition. This is an important tool for implementing quantum gates and other quantum information protocols with

  17. 75 FR 20541 - Homeless Emergency Assistance and Rapid Transition to Housing: Defining “Homeless”

    2010-04-20

    ... the proposal by name and docket number (FR-5333-P-01) and must be sent to: HUD Desk Officer, Office of... URBAN DEVELOPMENT 24 CFR Part 577 RIN 2506-AC26 Homeless Emergency Assistance and Rapid Transition to Housing: Defining ``Homeless'' AGENCY: Office of the Assistant Secretary for Community Planning...

  18. 77 FR 7080 - Changes To Implement Transitional Program for Covered Business Method Patents

    2012-02-10

    ... Flexibility Analysis for Patent-Related Regulations, 71 FR 67109 (Nov. 20, 2006), 1313 Off. Gaz. Pat. Office... Regulations, 71 FR at 67112 (Nov 20, 2006), 1313 Off. Gaz. Pat. Office at 63 (Dec. 12, 2006). As discussed... Patent and Trademark Office 37 CFR Part 42 RIN 0651-AC73 Changes To Implement Transitional Program...

  19. Strongly correlated perovskite fuel cells

    Zhou, You; Guan, Xiaofei; Zhou, Hua; Ramadoss, Koushik; Adam, Suhare; Liu, Huajun; Lee, Sungsik; Shi, Jian; Tsuchiya, Masaru; Fong, Dillon D.; Ramanathan, Shriram

    2016-06-01

    Fuel cells convert chemical energy directly into electrical energy with high efficiencies and environmental benefits, as compared with traditional heat engines. Yttria-stabilized zirconia is perhaps the material with the most potential as an electrolyte in solid oxide fuel cells (SOFCs), owing to its stability and near-unity ionic transference number. Although there exist materials with superior ionic conductivity, they are often limited by their ability to suppress electronic leakage when exposed to the reducing environment at the fuel interface. Such electronic leakage reduces fuel cell power output and the associated chemo-mechanical stresses can also lead to catastrophic fracture of electrolyte membranes. Here we depart from traditional electrolyte design that relies on cation substitution to sustain ionic conduction. Instead, we use a perovskite nickelate as an electrolyte with high initial ionic and electronic conductivity. Since many such oxides are also correlated electron systems, we can suppress the electronic conduction through a filling-controlled Mott transition induced by spontaneous hydrogen incorporation. Using such a nickelate as the electrolyte in free-standing membrane geometry, we demonstrate a low-temperature micro-fabricated SOFC with high performance. The ionic conductivity of the nickelate perovskite is comparable to the best-performing solid electrolytes in the same temperature range, with a very low activation energy. The results present a design strategy for high-performance materials exhibiting emergent properties arising from strong electron correlations.

  20. Direct-hydrogen-fueled proton-exchange-membrane fuel cell system for transportation applications: Conceptual vehicle design report pure fuel cell powertrain vehicle

    Oei, D.; Kinnelly, A.; Sims, R.; Sulek, M.; Wernette, D.

    1997-02-01

    In partial fulfillment of the Department of Energy (DOE) Contract No. DE-AC02-94CE50389, {open_quotes}Direct-Hydrogen-Fueled Proton-Exchange-Membrane (PEM) Fuel Cell for Transportation Applications{close_quotes}, this preliminary report addresses the conceptual design and packaging of a fuel cell-only powered vehicle. Three classes of vehicles are considered in this design and packaging exercise, the Aspire representing the small vehicle class, the Taurus or Aluminum Intensive Vehicle (AIV) Sable representing the mid-size vehicle and the E-150 Econoline representing the van-size class. A fuel cell system spreadsheet model and Ford`s Corporate Vehicle Simulation Program (CVSP) were utilized to determine the size and the weight of the fuel cell required to power a particular size vehicle. The fuel cell power system must meet the required performance criteria for each vehicle. In this vehicle design and packaging exercise, the following assumptions were made: fuel cell power system density of 0.33 kW/kg and 0.33 kg/liter, platinum catalyst loading less than or equal to 0.25 mg/cm{sup 2} total and hydrogen tanks containing gaseous hydrogen under 340 atm (5000 psia) pressure. The fuel cell power system includes gas conditioning, thermal management, humidity control, and blowers or compressors, where appropriate. This conceptual design of a fuel cell-only powered vehicle will help in the determination of the propulsion system requirements for a vehicle powered by a PEMFC engine in lieu of the internal combustion (IC) engine. Only basic performance level requirements are considered for the three classes of vehicles in this report. Each vehicle will contain one or more hydrogen storage tanks and hydrogen fuel for 560 km (350 mi) driving range. Under these circumstances, the packaging of a fuel cell-only powered vehicle is increasingly difficult as the vehicle size diminishes.