WorldWideScience

Sample records for based direct conversion

  1. Compressed Sensing-Based Direct Conversion Receiver

    DEFF Research Database (Denmark)

    Pierzchlewski, Jacek; Arildsen, Thomas; Larsen, Torben

    2012-01-01

    Due to the continuously increasing computational power of modern data receivers it is possible to move more and more processing from the analog to the digital domain. This paper presents a compressed sensing approach to relaxing the analog filtering requirements prior to the ADCs in a direct...... conversion receiver. In the presented solution, the filtered down-converted radio signals are randomly sampled with an average sampling frequency lower than its Nyquist rate, and then reconstructed in a DSP system. To enable compressed sensing, this approach exploits the frequency domain sparsity of the down...

  2. Direct Conversion of Energy

    Energy Technology Data Exchange (ETDEWEB)

    Corliss, William R

    1964-01-01

    Topics include: direct versus dynamic energy conversion; laws governing energy conversion; thermoelectricity; thermionic conversion; magnetohydrodynamic conversion; chemical batteries; the fuel cell; solar cells; nuclear batteries; and advanced concepts including ferroelectric conversion and thermomagnetic conversion.

  3. New Petrochemical Processes Based on Direct Conversion of Methane

    Directory of Open Access Journals (Sweden)

    Faraguna F.

    2015-01-01

    Full Text Available Petrochemistry is a branch of chemistry and chemical engineering that studies reactions and processes of the transformation of petroleum derivatives and natural gas into useful petrochemicals. In its beginning, petrochemistry, or rather the organic chemical industry, was based on the acetylene and Reppe chemistry. The main raw materials of the petrochemical industry nowadays are olefins and aromatic hydrocarbons, with a pronounced tendency toward development of new processes and higher usage of syngas, methane and other alkanes. Here, the reactions and new processes of direct conversion of methane into more valuable petrochemicals are reviewed. Reactions of partial oxidation of methane, dehydroaromatization of methane, oxidative and non-oxidative coupling of methane to higher hydrocarbons are also described and discussed.

  4. Direct energy conversion

    International Nuclear Information System (INIS)

    Chalupa, Z.; Kramar, J.

    1975-01-01

    The current state of research of direct energy conversion is briefly discussed and a more detailed description is given of MHD and thermionic energy conversion. Current and prospective values of characteristic variables of various energy conversion methods are listed. MHD generators produce terminal voltage of the same order as turbogenerators while other generators for direct energy conversion only produce voltages of 0.1 to 1.5 V so that the respective elements must be parallel-connected. From the point of view of current density, thermionic conversion having the emitter surface value in the order of 10 A/cm 2 ranks first. As for MHD generators, main attention is devoted to open-cycle generators with combustion products as the working medium. It is envisaged that after 1980 MHD power plants will be commissioned having an electric output of up to 500 MW. By 1990, the construction should be started of basic MHD power plants with a total thermal efficiency of about 55%. The research of thermionic conversion focused on practical applications has mainly been concentrated on nuclear power converters. Nuclear or isotope converters have already been built and used in a number of specific applications as low-power sources, e.g., in space exploration, etc. Preparations are under way for applying high-power sources in telecommunication satellites (USSR, USA). (Z.S.)

  5. Direct conversion of fusion energy

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Markus

    2003-03-01

    Deuterium and tritium are expected to be used as fuel in the first fusion reactors. Energy is released as kinetic energy of ions and neutrons, when deuterium reacts with tritium. One way to convert the kinetic energy to electrical energy, is to let the ions and neutrons hit the reactor wall and convert the heat that is caused by the particle bombardment to electrical energy with ordinary thermal conversion. If the kinetic energy of the ions instead is converted directly to electrical energy, a higher efficiency of the energy conversion is possible. The majority of the fusion energy is released as kinetic energy of neutrons, when deuterium reacts with tritium. Fusion reactions such as the D-D reactions, the D-{sup 3}He reaction and the p-{sup 11}B reaction, where a larger part of the fusion energy becomes kinetic energy of charged particles, appears therefore more suitable for direct conversion. Since they have lower reactivity than the D-T reaction, they need a larger {beta}B{sup 2}{sub 0} to give sufficiently high fusion power density. Because of this, the fusion configurations spherical torus (ST) and field-reversed configuration (FRC), where high {beta} values are possible, appear interesting. Rosenbluth and Hinton come to the conclusion that efficient direct conversion isn't possible in closed field line systems and that open geometries, which facilitate direct conversion, provide inadequate confinement for D-{sup 3}He. It is confirmed in this study that it doesn't seem possible to achieve as high direct conversion efficiency in closed systems as in open systems. ST and FRC fusion power plants that utilize direct conversion seem however interesting. Calculations with the help of Maple indicate that the reactor parameters needed for a D-D ST and a D{sub 3} He ST hopefully are possible to achieve. The best energy conversion option for a D-D or D{sub 3} He ST appears to be direct electrodynamic conversion (DEC) together with ordinary thermal conversion

  6. A perspective on direct conversion

    International Nuclear Information System (INIS)

    Lewis, W.B.

    1963-10-01

    As flowing energy, electricity is sought for its versatility. Its generation from some other flow or release of energy without mechanical power, or even sometimes heat, as intermediary is called direct conversion. The objective is high electrical output for minimum total cost and not always high conversion efficiency. The wide range of techniques embracing cryogenics and hot plasma derives from the special requirements of source, environment and application. Sources include solar and other radiation, nuclear fission and fusion, chemical energy and heat. Environments and applications range from space vehicles to submarines and from giant power networks to isolated buoys and pocket devices. (author)

  7. Power production with direct energy conversion

    International Nuclear Information System (INIS)

    Rochau, G.; Lipinski, R.; Polansky, G.; Seidel, D.; Slutz, S.; Morrow, C.; Anghaie, S.; Beller, D.; Brown, L.; Parish, T.

    2001-01-01

    The direct energy conversion (DEC) project has as its main goal the development of a direct energy conversion process suitable for commercial development. We define direct energy conversion as any fission process that returns usable energy without using an intermediate thermal process. During the first phase of study, nine different concepts were investigated and 3 were selected: 1) quasi-spherical magnetically insulated fission electrode cell, 2) fission fragment magnetic collimator, and 3) gaseous core reactor with MHD generator. Selection was based on efficiency and feasibility. The realization of their potential requires an investment in both technically and commercially oriented research. The DEC project has a process in place to take one of these concepts forward and to outline the road map for further development. (A.C.)

  8. Solar power conversion system with directionally- and spectrally-selective properties based on a reflective cavity

    Science.gov (United States)

    Boriskina, Svetlana; Kraemer, Daniel; McEnaney, Kenneth; Weinstein, Lee A.; Chen, Gang

    2018-03-13

    Solar power conversion system. The system includes a cavity formed within an enclosure having highly specularly reflecting in the IR spectrum inside walls, the enclosure having an opening to receive solar radiation. An absorber is positioned within the cavity for receiving the solar radiation resulting in heating of the absorber structure. In a preferred embodiment, the system further contains an energy conversion and storage devices thermally-linked to the absorber by heat conduction, convection, far-field or near-field thermal radiation.

  9. Special section on beam direct conversion

    International Nuclear Information System (INIS)

    Yoshikawa, K.

    1990-01-01

    In fusion, there are two possible direct energy conversion methods: plasma direct energy conversion (PDC), which recovers the plasma energy leaking out of the confined region, and beam direct energy conversion (BDC), which recovers the unneutralized energetic ion energy in a neutral beam injection (NBI) system used for plasma heating and to sustain current. In the very powerful near-term NBI systems in fusion devices such as the International Thermonuclear Experiment Reactor (ITER), Next European Torus (NET), or Fusion Experimental Reactor (FER), on the other hand, the innovative BDC will be very efficient in recovering huge amounts of energy. Five papers in this section describe the results of BDC proof-of-principle experiments or advanced BDC concepts: two papers related to BDC experiments in small-scale positive-ion-based NBI systems and one in an NBI system of practical size, as well as two three-dimensional conceptual design studies of advanced BDC concepts for a 500-keV negative-ion-based NBI system in the near-term FER fusion reactor being developed at JAERI, where both negative and positive ions need to be effectively recovered

  10. Importance of direct energy conversion

    International Nuclear Information System (INIS)

    Pavlicek, Z.

    1973-01-01

    Energy reserves of different types (fossil fuels, nuclear fission and fusion reactions, solar and geothermal energy) are listed and their conversion patterns evaluated with regard to economic and ecological factors and to the siting of power plants. The concepts and economy of different types of power plants are discussed. The magnetohydrodynamic conversion is given detailed analysis being the most promising for nuclear power production. MHD power plants are expected to operate as peak plants. The graphs presented show that the combination of an MHD reactor and gas turbines is the least costly

  11. Particle Discrimination Experiment for Direct Energy Conversion

    International Nuclear Information System (INIS)

    Yasaka, Y.; Kiriyama, Y.; Yamamoto, S.; Takeno, H.; Ishikawa, M.

    2005-01-01

    A direct energy conversion system designed for D- 3 He fusion reactor based on a field reversed configuration employs a venetian-blind type converter for thermal ions to produce DC power and a traveling wave type converter for fusion protons to produce RF power. It is therefore necessary to separate, discriminate, and guide the particle species. For this purpose, a cusp magnetic field is proposed, in which the electrons are deflected and guided along the field line to the line cusp, while the ions pass through the point cusp. A small-scale experimental device was used to study the basic characteristics of discrimination of electrons and ions in the cusp magnetic field. Ions separated from electrons are guided to an ion collector, which is operated as a one-stage direct energy converter. The conversion efficiency was measured for cases with different values of mean and spread of ion energy. These experiments successfully demonstrate direct energy conversion from plasma beams using particle discrimination by a cusp magnetic field

  12. A New Cost-Effective Multi-Drive Solution based on a Two-Stage Direct Power Electronic Conversion Topology

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede

    2002-01-01

    The matrix converter is a single stage AC/AC converter, which is able to provide sinusoidal PWM output voltages and input currents, inherent bi-directional power flow with no need of bulky DC-capacitors and large line inductors. However, the increased number of active switches (18) and the need o...... shared by many loads, making this topology more cost effective. The functionality of the proposed two-stage multi-drive direct power electronic conversion topology is validated by experiments on a realistic laboratory prototype.......The matrix converter is a single stage AC/AC converter, which is able to provide sinusoidal PWM output voltages and input currents, inherent bi-directional power flow with no need of bulky DC-capacitors and large line inductors. However, the increased number of active switches (18) and the need...... of a protection circuit involving twelve diodes with full voltage/current ratings used only during faulty situations, makes this topology not so attractive. Lately, two stage Direct Power Electronic Conversion (DPEC) topologies have been proposed, providing similar functionality as a matrix converter but allowing...

  13. A New Cost-Effective Multi-Drive Solution based on a Two-Stage Direct Power Electronic Conversion Topology

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede

    2002-01-01

    The matrix converter is a single stage AC/AC converter, which is able to provide sinusoidal PWM output voltages and input currents, inherent bi-directional power flow with no need of bulky DC-capacitors and large line inductors. However, the increased number of active switches (18) and the need...... for a reduction of power devices. In this paper, a new DPEC topology suited for multi-drive application is proposed, having an input port for a three-phase power supply and several output ports to connect three-phase loads, which are independently controlled. The cost of the rectification stage is therefore...... shared by many loads, making this topology more cost effective. The functionality of the proposed two-stage multi-drive direct power electronic conversion topology is validated by experiments on a realistic laboratory prototype....

  14. Direct conversion of algal biomass to biofuel

    Science.gov (United States)

    Deng, Shuguang; Patil, Prafulla D; Gude, Veera Gnaneswar

    2014-10-14

    A method and system for providing direct conversion of algal biomass. Optionally, the method and system can be used to directly convert dry algal biomass to biodiesels under microwave irradiation by combining the reaction and combining steps. Alternatively, wet algae can be directly processed and converted to fatty acid methyl esters, which have the major components of biodiesels, by reacting with methanol at predetermined pressure and temperature ranges.

  15. Thermoelectric direct energy conversion system for fast reactors

    International Nuclear Information System (INIS)

    Kambe, Mitsuru

    1995-01-01

    A concept of direct energy conversion system for fast reactors has been presented by using FGM thermoelectric (TE) cell elements combined with FGM compliant pads based on the assumption that energy conversion efficiency of 20% could be achieved. The design involves TE energy conversion modules in which 360 TE cell elements are assembled. These energy conversion modules are connected to sodium and water circuits by cesium heat pipes and water heat pipes, respectively. The following design approach has been demonstrated. 1) Approximately 4100 energy conversion modules installed in a 150 MWt fast reactor can affords 27 MW of electricity. 2) An energy conversion building (single floor, 15 m x 15 m) enables to eliminate intermediate heat exchangers, steam generators and sodium-water reaction counter measures. (author)

  16. Direct Energy Conversion for Fast Reactors

    International Nuclear Information System (INIS)

    Brown, N.; Cooper, J.; Vogt, D.; Chapline, G.; Turchi, P.; Barbee Jr., T.; Farmer, J.

    2000-01-01

    Thermoelectric generators (TEG) are a well-established technology for compact low power output long-life applications. Solid state TEGs are the technology of choice for many space missions and have also been used in remote earth-based applications. Since TEGs have no moving parts and can be hermetically sealed, there is the potential for nuclear reactor power systems using TEGs to be safe, reliable and resistant to proliferation. Such power units would be constructed in a manner that would provide decades of maintenance-free operation, thereby minimizing the possibility of compromising the system during routine maintenance operations. It should be possible to construct an efficient direct energy conversion cascade from an appropriate combination of solid-state thermoelectric generators, with each stage in the cascade optimized for a particular range of temperature. Performance of cascaded thermoelectric devices could be further enhanced by exploitation of compositionally graded p-n couples, as well as radial elements to maximize utilization of the heat flux. The Jet Propulsion Laboratory in Pasadena has recently reported segmented unicouples that operate between 300 and 975 K and have conversion efficiencies of 15 percent [Caillat, 2000]. TEGs are used in nuclear-fueled power sources for space exploration, in power sources for the military, and in electrical generators on diesel engines. Second, there is a wide variety of TE materials applicable to a broad range of temperatures. New materials may lead to new TEG designs with improved thermoelectric properties (i.e. ZT approaching 3) and significantly higher efficiencies than in designs using currently available materials. Computational materials science (CMS) has made sufficient progress and there is promise for using these techniques to reduce the time and cost requirements to develop such new TE material combinations. Recent advances in CMS, coupled with increased computational power afforded by the Accelerated

  17. High-performance direct conversion X-ray detectors based on sintered hybrid lead triiodide perovskite wafers

    Science.gov (United States)

    Shrestha, Shreetu; Fischer, René; Matt, Gebhard J.; Feldner, Patrick; Michel, Thilo; Osvet, Andres; Levchuk, Ievgen; Merle, Benoit; Golkar, Saeedeh; Chen, Haiwei; Tedde, Sandro F.; Schmidt, Oliver; Hock, Rainer; Rührig, Manfred; Göken, Mathias; Heiss, Wolfgang; Anton, Gisela; Brabec, Christoph J.

    2017-07-01

    Lead halide perovskite semiconductors are in general known to have an inherently high X-ray absorption cross-section and a significantly higher carrier mobility than any other low-temperature solution-processed semiconductor. So far, the processing of several-hundred-micrometres-thick high-quality crystalline perovskite films over a large area has been unresolved for efficient X-ray detection. In this Article, we present a mechanical sintering process to fabricate polycrystalline methyl ammonium lead triiodide perovskite (MAPbI3) wafers with millimetre thickness and well-defined crystallinity. Benchmarking of the MAPbI3 wafers against state-of-the-art CdTe detectors reveals competitive conversion efficiencies of 2,527 µC Gyair-1 cm-2 under 70 kVp X-ray exposure. The high ambipolar mobility-lifetime product of 2 × 10-4 cm2 V-1 is suggested to be responsible for this exceptionally high sensitivity. Our findings inform a new generation of highly efficient and low-cost X-ray detectors based on perovskite wafers.

  18. Carbon aerogel electrodes for direct energy conversion

    Science.gov (United States)

    Mayer, Steven T.; Kaschmitter, James L.; Pekala, Richard W.

    1997-01-01

    A direct energy conversion device, such as a fuel cell, using carbon aerogel electrodes, wherein the carbon aerogel is loaded with a noble catalyst, such as platinum or rhodium and soaked with phosphoric acid, for example. A separator is located between the electrodes, which are placed in a cylinder having plate current collectors positioned adjacent the electrodes and connected to a power supply, and a pair of gas manifolds, containing hydrogen and oxygen positioned adjacent the current collectors. Due to the high surface area and excellent electrical conductivity of carbon aerogels, the problems relative to high polarization resistance of carbon composite electrodes conventionally used in fuel cells are overcome.

  19. NEBNext Direct: A Novel, Rapid, Hybridization-Based Approach for the Capture and Library Conversion of Genomic Regions of Interest.

    Science.gov (United States)

    Emerman, Amy B; Bowman, Sarah K; Barry, Andrew; Henig, Noa; Patel, Kruti M; Gardner, Andrew F; Hendrickson, Cynthia L

    2017-07-05

    Next-generation sequencing (NGS) is a powerful tool for genomic studies, translational research, and clinical diagnostics that enables the detection of single nucleotide polymorphisms, insertions and deletions, copy number variations, and other genetic variations. Target enrichment technologies improve the efficiency of NGS by only sequencing regions of interest, which reduces sequencing costs while increasing coverage of the selected targets. Here we present NEBNext Direct ® , a hybridization-based, target-enrichment approach that addresses many of the shortcomings of traditional target-enrichment methods. This approach features a simple, 7-hr workflow that uses enzymatic removal of off-target sequences to achieve a high specificity for regions of interest. Additionally, unique molecular identifiers are incorporated for the identification and filtering of PCR duplicates. The same protocol can be used across a wide range of input amounts, input types, and panel sizes, enabling NEBNext Direct to be broadly applicable across a wide variety of research and diagnostic needs. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  20. Modulation method for a multiple drive system based on a two-stage direct power conversion topology with reduced input current ripple

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede

    2005-01-01

    A new two-stage multi-drive direct power conversion (DPC) topology suited for multi-drive application is proposed, having an input port for a three-phase power supply and several output ports to connect three-phase loads, which are independently controlled and allow for sine wave in-sine wave out...... operation. This is a cost effective topology compared to a standard matrix converter because the multiple three-phase loads share the cost of the controlled rectification stage. A new method to reduce the high frequency ripple from the input current is also proposed based on interleaving the switching...... patterns of the inversion stages, which have to form two groups, allowing for size reduction of the input current filter. This is validated by experiments on a realistic laboratory prototype, while its limitations are determined by simulations....

  1. Wavelength conversion based spectral imaging

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin

    There has been a strong, application driven development of Si-based cameras and spectrometers for imaging and spectral analysis of light in the visible and near infrared spectral range. This has resulted in very efficient devices, with high quantum efficiency, good signal to noise ratio and high...... resolution for this spectral region. Today, an increasing number of applications exists outside the spectral region covered by Si-based devices, e.g. within cleantech, medical or food imaging. We present a technology based on wavelength conversion which will extend the spectral coverage of state of the art...... visible or near infrared cameras and spectrometers to include other spectral regions of interest....

  2. Direct energy conversion for fusion reactors

    International Nuclear Information System (INIS)

    Barr, W.L.

    1977-01-01

    Complex multistage plasma converters were tested at efficiencies approaching 90% at low energies and powers, and simpler, more cost-effective versions at 65% efficiency. Laboratory tests of neutral-beam direct converters at 15 keV and 2 kW gave 70% efficiency. A 120-keV, 1.5-MW version is being tested

  3. Review of direct energy conversion for fusion reactors

    International Nuclear Information System (INIS)

    Barr, W.L.; Moir, R.W.

    1976-01-01

    The direct conversion to electrical energy of the energy carried by the leakage plasma from a fusion reactor and by the ions that are not converted to neutrals in a neutral-beam injector is discussed. The conversion process is electrostatic deceleration and direct particle collection as distinct from plasma expansion against a time-varying magnetic field or conversion in an EXB duct (both MHD). Relatively simple 1-stage plasma direct converters are discussed which can have efficiencies of about 50 percent. More complex and costly (measured in $/kW) 2-, 3-, 4-, and 22-stage concepts have been tested at efficiencies approaching 90 percent. Beam direct converters have been tested at 15 keV and 2 kW of power at 70 +- 2 percent efficiency, and a test of a 120-keV, 1-MW version is being prepared. Designs for a 120-keV, 4-MW unit are presented. The beam direct converter, besides saving on power supplies and on beam dumps, should raise the efficiency of creating a neutral beam from 40 percent without direct conversion to 70 percent with direct conversion for a 120-keV deuterium beam. The technological limits determining power handling and lifetime such as space-charge effects, heat removal, electrode material, sputtering, blistering, voltage holding, and insulation design, are discussed. The application of plasma direct converters to toroidal plasma confinement concepts is also discussed

  4. Direct conversion nuclear reactor space power systems

    International Nuclear Information System (INIS)

    Britt, E.J.; Fitzpatrick, G.O.

    1982-01-01

    This paper presents the results of a study of space nuclear reactor power systems using either thermoelectric or thermionic energy converters. An in-core reactor design and two heat pipe cooled out-of-core reactor designs were considered. One of the out-of-core cases utilized, long heat pipes (LHP) directly coupled to the energy converter. The second utilized a larger number of smaller heat pipes (mini-pipe) radiatively coupled to the energy converter. In all cases the entire system, including power conditioning, was constrained to be launched in a single shuttle flight. Assuming presently available performance, both the LHP thermoelectric system and minipipe thermionic system, designed to produce 100 kWe for seven years, would have a specific mass near 22kg/kWe. The specific mass of the thermionic minipipe system designed for a one year mission is 165 kg/kWe due to less fuel swelling. Shuttle imposed growth limits are near 300 kWe and 1.2 MWe for the thermoelectric and thermionic systems, respectively. Converter performance improvements could double this potential, and over 10 MWe may be possible for very short missions

  5. Systems modeling for a laser-driven IFE power plant using direct conversion

    International Nuclear Information System (INIS)

    Meier, W R

    2008-01-01

    A variety of systems analyses have been conducted for laser driver IFE power plants being developed as part of the High Average Power Laser (HAPL) program. A key factor determining the economics attractiveness of the power plant is the net power conversion efficiency which increases with increasing laser efficiency, target gain and fusion-to-electric power conversion efficiency. A possible approach to increasing the power conversion efficiency is direct conversion of ionized target emissions to electricity. This study examines the potential benefits of increased efficiency when the expanding plasma is inductively coupled to an external circuit allowing some of the ion energy to be directly converted to electricity. For base case direct-drive targets with approximately 24% of the target yield in ions, the benefits are modest, especially for chamber designs that operate at high temperature and thus already have relatively high thermal conversion efficiencies. The reduction in the projected cost of electricity is ∼5-10%

  6. Reflection during Portfolio-Based Conversations

    Science.gov (United States)

    Oosterbaan, Anne E.; van der Schaaf, Marieke F.; Baartman, Liesbeth K. J.; Stokking, Karel M.

    2010-01-01

    This study aims to explore the relationship between the occurrence of reflection (and non-reflection) and thinking activities (e.g., orientating, selecting, analysing) during portfolio-based conversations. Analysis of 21 transcripts of portfolio-based conversations revealed that 20% of the segments were made up of reflection (content reflection…

  7. Calibration method for direct conversion receiver front-ends

    Directory of Open Access Journals (Sweden)

    R. Müller

    2008-05-01

    Full Text Available Technology induced process tolerances in analog circuits cause device characteristics different from specification. For direct conversion receiver front-ends a system level calibration method is presented. The malfunctions of the devices are compensated by tuning dominant circuit parameters. Thereto optimization techniques are applied which use measurement values and special evaluation functions.

  8. Switching-mode Audio Power Amplifiers with Direct Energy Conversion

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2005-01-01

    has been replaced with a high frequency AC link. When compared to the conventional Class D amplifiers with a separate DC power supply, the proposed single conversion stage amplifier provides simple and compact solution with better efficiency and higher level of integration, leading to reduced......This paper presents a new class of switching-mode audio power amplifiers, which are capable of direct energy conversion from the AC mains to the audio output. They represent an ultimate integration of a switching-mode power supply and a Class D audio power amplifier, where the intermediate DC bus...

  9. Key Roles of Lewis Acid-Base Pairs on ZnxZryOz in Direct Ethanol/Acetone to Isobutene Conversion.

    Science.gov (United States)

    Sun, Junming; Baylon, Rebecca A L; Liu, Changjun; Mei, Donghai; Martin, Kevin J; Venkitasubramanian, Padmesh; Wang, Yong

    2016-01-20

    The effects of surface acidity on the cascade ethanol-to-isobutene conversion were studied using ZnxZryOz catalysts. The ethanol-to-isobutene reaction was found to be limited by the secondary reaction of the key intermediate, acetone, namely the acetone-to-isobutene reaction. Although the catalysts with coexisting Brønsted acidity could catalyze the rate-limiting acetone-to-isobutene reaction, the presence of Brønsted acidity is also detrimental. First, secondary isobutene isomerization is favored, producing a mixture of butene isomers. Second, undesired polymerization and coke formation prevail, leading to rapid catalyst deactivation. Most importantly, both steady-state and kinetic reaction studies as well as FTIR analysis of adsorbed acetone-d6 and D2O unambiguously showed that a highly active and selective nature of balanced Lewis acid-base pairs was masked by the coexisting Brønsted acidity in the aldolization and self-deoxygenation of acetone to isobutene. As a result, ZnxZryOz catalysts with only Lewis acid-base pairs were discovered, on which nearly a theoretical selectivity to isobutene (∼ 88.9%) was successfully achieved, which has never been reported before. Moreover, the absence of Brønsted acidity in such ZnxZryOz catalysts also eliminates the side isobutene isomerization and undesired polymerization/coke reactions, resulting in the production of high purity isobutene with significantly improved catalyst stability (catalyst for C-C coupling via aldolization reaction.

  10. Key Roles of Lewis Acid-base Pairs on ZnxZryOz in Direct Ethanol/Acetone to Isobutene Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Junming; Baylon, Rebecca A.; Liu, Changjun; Mei, Donghai; Martin, Kevin J.; Venkitasubramanian, Padmesh; Wang, Yong

    2016-01-20

    The effects of surface acidity on the cascade ethanol-to-isobutene conversion were studied using ZnxZryOz catalysts. The ethanol-to-isobutene reaction was found to be limited by the secondary reaction of the key intermediate, acetone, namely the acetone-to-isobutene reaction. Although the catalysts with coexisting Brønsted acidity could catalyze the rate-limiting acetone-to-isobutene reaction, the presence of Brønsted acidity is also detrimental. First, secondary isobutene isomerization is favored, producing a mixture of butene isomers. Second, undesired polymerization and coke formation prevail, leading to rapid catalyst deactivation. Most importantly, both steady-state and kinetic reaction studies as well as FTIR analysis of adsorbed acetone-d6 and D2O unambiguously showed that a highly active and selective nature of balanced Lewis acid-base pairs was masked by the coexisting Brønsted acidity in the aldolization and self-deoxygenation of acetone to isobutene. As a result, ZnxZryOz catalysts with only Lewis acid-base pairs were discovered, on which nearly a theoretical selectivity to isobutene (~88.9%) was successfully achieved, which has never been reported before. Moreover, the absence of Brønsted acidity in such ZnxZryOz catalysts also eliminates the side isobutene isomerization and undesired polymerization/coke reactions, resulting in the production of high purity isobutene with significantly improved catalyst stability (< 2% activity loss after 200 h time-on-stream). This work not only demonstrates a balanced Lewis acid-base pair for the highly active and selective cascade ethanol-to-isobutene reaction, but also sheds light on the rational design of selective and robust acid-base catalyst for C-C coupling via aldolization reaction.

  11. Conversion of direct process high-boiling residue to monosilanes

    Science.gov (United States)

    Brinson, Jonathan Ashley; Crum, Bruce Robert; Jarvis, Jr., Robert Frank

    2000-01-01

    A process for the production of monosilanes from the high-boiling residue resulting from the reaction of hydrogen chloride with silicon metalloid in a process typically referred to as the "direct process." The process comprises contacting a high-boiling residue resulting from the reaction of hydrogen chloride and silicon metalloid, with hydrogen gas in the presence of a catalytic amount of aluminum trichloride effective in promoting conversion of the high-boiling residue to monosilanes. The present process results in conversion of the high-boiling residue to monosilanes. At least a portion of the aluminum trichloride catalyst required for conduct of the process may be formed in situ during conduct of the direct process and isolation of the high-boiling residue.

  12. Direct energy conversion of radiation energy in fusion reactor

    International Nuclear Information System (INIS)

    Yamaguchi, S.; Iiyoshi, A.; Motojima, O.; Okamoto, M.; Sudo, S.; Ohnishi, M.; Onozuka, M.; Uenosono, C.

    1993-11-01

    Direct energy conversion from plasma heat flux has been studied. Since major parts of fusion energy in the advanced fusion reactor are radiation and charged particle energies, the flexible design of the blanket is possible. We discuss the potentiality of the thermoelectric element that generates electricity by temperature gradient in conductors. A strong magnetic field is used to confine the fusion plasma, therefore, it is appropriate to consider the effect of the magnetic field. We propose a new element which is called Nernst element. The new element needs the magnetic field and the temperature gradient. We compare the efficiency of these two elements in a semiconductor model. Finally, a direct energy conversion are mentioned. (author)

  13. Direct energy conversion system for D(3)-He fusion

    Science.gov (United States)

    Tomita, Y.; Shu, L. Y.; Momota, H.

    1993-11-01

    A novel and highly efficient direct energy conversion system is proposed for utilizing D(3)-He fueled fusion. In order to convert kinetic energy of ions, we applied a pair of direct energy conversion systems each of which has a cusp-type DEC and a traveling wave DEC (TWDEC). In a cusp-type DEC, electrons are separated from the escaping ions at the first line-cusp and the energy of thermal ion components is converted at the second cusp DEC. The fusion protons go through the cusp-type DEC and arrive at the TWDEC, which principle is similar to 'LINAC'. The energy of fusion protons is recovered to electricity with an efficiency of more than 70%. These DEC's bring about the high efficient fusion plant.

  14. The Signal and Noise Analysis of Direct Conversion EHM Transceivers

    Directory of Open Access Journals (Sweden)

    Shayegh

    2006-01-01

    Full Text Available A direct conversion modulator-demodulator with even harmonic mixers with emphasis on noise analysis is presented. The circuits consist of even harmonic mixers (EHMs realized with antiparallel diode pairs (APDPs. We evaluate the different levels of I/Q imbalances and DC offsets and use signal space concepts to analyze the bit error rate (BER of the proposed transceiver using M-ary QAM schemes. Moreover, the simultaneous analysis of the signal and noise has been presented.

  15. Direct, nonoxidative conversion of methane to ethylene, aromatics, and hydrogen.

    Science.gov (United States)

    Guo, Xiaoguang; Fang, Guangzong; Li, Gang; Ma, Hao; Fan, Hongjun; Yu, Liang; Ma, Chao; Wu, Xing; Deng, Dehui; Wei, Mingming; Tan, Dali; Si, Rui; Zhang, Shuo; Li, Jianqi; Sun, Litao; Tang, Zichao; Pan, Xiulian; Bao, Xinhe

    2014-05-09

    The efficient use of natural gas will require catalysts that can activate the first C-H bond of methane while suppressing complete dehydrogenation and avoiding overoxidation. We report that single iron sites embedded in a silica matrix enable direct, nonoxidative conversion of methane, exclusively to ethylene and aromatics. The reaction is initiated by catalytic generation of methyl radicals, followed by a series of gas-phase reactions. The absence of adjacent iron sites prevents catalytic C-C coupling, further oligomerization, and hence, coke deposition. At 1363 kelvin, methane conversion reached a maximum at 48.1% and ethylene selectivity peaked at 48.4%, whereas the total hydrocarbon selectivity exceeded 99%, representing an atom-economical transformation process of methane. The lattice-confined single iron sites delivered stable performance, with no deactivation observed during a 60-hour test.

  16. The direct conversion of heat into electricity in reactors

    International Nuclear Information System (INIS)

    Devin, B.; Bliaux, J.; Lesueur, R.

    1964-01-01

    The direct conversion of heat into electricity by thermionic emission in an atomic reactor has been studied with the triple aim of its utilisation: as an energy source for a space device, at the head of a conventional conversion system in power installations, or finally in association with the thermoelectric conversion in very low power installations. The laboratory experiments were mainly orientated towards the electron extraction of metals and compounds and their behaviour at high temperatures. Converters furnishing up to 50 amps at 0. 4 volts with an efficiency close to 10 p. 100 have been constructed in the laboratory; the emitters were heated by electron bombardment and were composed of tungsten covered with an uranium carbide deposit or molybdenum covered with cesium. The main aspects of the coupling between the converter and the reactor have been covered from the point of view of electronics: the influence of the mismatching of the load on the temperature of the emitter and the influence of thermal flux density on the temperature of the emitter and the stability of the converter. Converters using uranium carbide as the electron emitter have been tested in reactors. Tests have been made under dynamic conditions in order to determine the dynamic characteristics. The load matching curves have been constructed and the overall performances of several cells coupled in such a way as to form a reactor rod have been deduced. This information is fundamental to the design of a control system for a thermionic conversion reactor. The problems associated with the reliability of thermionic converters connected in series in the same reactor rod have been examined theoretically. Finally, the absorption isotherms have been drawn at the ambient temperatures for krypton and xenon on activated carbon with the aim of investigating the escape of fission products in a converter. (author) [fr

  17. Efficiency of a Directly Driven Generator for Hydrokinetic Energy Conversion

    Directory of Open Access Journals (Sweden)

    Mårten Grabbe

    2013-01-01

    Full Text Available An experimental setup for hydrokinetic energy conversion comprising a vertical axis turbine, a directly driven permanent magnet generator, and a control system has been designed and constructed for deployment in the river Dalälven in Sweden. This paper is devoted to discussing the mechanical and electrical design of the generator used in the experimental setup. The generator housing is designed to be water tight, and it also acts as a support structure for the turbine shaft. The generator efficiency has been measured in the range of 5–16.7 rpm, showing that operation in the low velocity range up to 1.5 m/s is possible with a directly driven generator.

  18. Direct energy conversion for IEC fusion for space applications

    International Nuclear Information System (INIS)

    Momota, Hiromu; Nadler, Jon; Miley, George H.

    2000-08-01

    The paper describes a concept of extracting fusion power from D- 3 He fueled IEC (Inertia Electrostatic Configuration) devices. The fusion system consists of a series of fusion modules and direct energy converters at an end or at both ends. This system of multiple units is linear and is connected by a magnetic field. A pair of coils anti-parallel to the magnetic field yields a field-null domain at the center of each unit as required for IEC operation. A stabilizing coil installed between the coil pairs eliminates the strong attractive force between the anti-parallel coils. Accessible regions for charged particle trajectories are essentially isolated from the coil structure. Thus, charged particles are directed along magnetic field lines to the direct energy converter without appreciable losses. A direct energy converter unit designed to be compatible to this unique system is also described. It basically consists of a separator and a traveling wave converter. A separator separates low energy ions and electron from the 14.7 MeV fusion protons and then converts their energy into electricity. In the traveling wave direct energy converter, fusion protons are modulated to form bunches. It couples with a transmission line to couple AC power out. The overall conversion efficiency of this system, combined with E- 3 He IEC cores, is estimated as high as 60%. (author)

  19. Direct energy conversion for IEC fusion for space applications

    Energy Technology Data Exchange (ETDEWEB)

    Momota, Hiromu; Nadler, Jon [National Inst. for Fusion Science, Toki, Gifu (Japan); Miley, George H. [Fusion Studies Laboratory, Urbana, IL (United States)

    2000-08-01

    The paper describes a concept of extracting fusion power from D-{sup 3}He fueled IEC (Inertia Electrostatic Configuration) devices. The fusion system consists of a series of fusion modules and direct energy converters at an end or at both ends. This system of multiple units is linear and is connected by a magnetic field. A pair of coils anti-parallel to the magnetic field yields a field-null domain at the center of each unit as required for IEC operation. A stabilizing coil installed between the coil pairs eliminates the strong attractive force between the anti-parallel coils. Accessible regions for charged particle trajectories are essentially isolated from the coil structure. Thus, charged particles are directed along magnetic field lines to the direct energy converter without appreciable losses. A direct energy converter unit designed to be compatible to this unique system is also described. It basically consists of a separator and a traveling wave converter. A separator separates low energy ions and electron from the 14.7 MeV fusion protons and then converts their energy into electricity. In the traveling wave direct energy converter, fusion protons are modulated to form bunches. It couples with a transmission line to couple AC power out. The overall conversion efficiency of this system, combined with E-{sup 3}He IEC cores, is estimated as high as 60%. (author)

  20. Carbon dioxide conversion over carbon-based nanocatalysts.

    Science.gov (United States)

    Khavarian, Mehrnoush; Chai, Siang-Piao; Mohamed, Abdul Rahman

    2013-07-01

    The utilization of carbon dioxide for the production of valuable chemicals via catalysts is one of the efficient ways to mitigate the greenhouse gases in the atmosphere. It is known that the carbon dioxide conversion and product yields are still low even if the reaction is operated at high pressure and temperature. The carbon dioxide utilization and conversion provides many challenges in exploring new concepts and opportunities for development of unique catalysts for the purpose of activating the carbon dioxide molecules. In this paper, the role of carbon-based nanocatalysts in the hydrogenation of carbon dioxide and direct synthesis of dimethyl carbonate from carbon dioxide and methanol are reviewed. The current catalytic results obtained with different carbon-based nanocatalysts systems are presented and how these materials contribute to the carbon dioxide conversion is explained. In addition, different strategies and preparation methods of nanometallic catalysts on various carbon supports are described to optimize the dispersion of metal nanoparticles and catalytic activity.

  1. Direct Energy Conversion for Nuclear Propulsion at Low Specific Mass

    Science.gov (United States)

    Scott, John H.

    2014-01-01

    The project will continue the FY13 JSC IR&D (October-2012 to September-2013) effort in Travelling Wave Direct Energy Conversion (TWDEC) in order to demonstrate its potential as the core of a high potential, game-changing, in-space propulsion technology. The TWDEC concept converts particle beam energy into radio frequency (RF) alternating current electrical power, such as can be used to heat the propellant in a plasma thruster. In a more advanced concept (explored in the Phase 1 NIAC project), the TWDEC could also be utilized to condition the particle beam such that it may transfer directed kinetic energy to a target propellant plasma for the purpose of increasing thrust and optimizing the specific impulse. The overall scope of the FY13 first-year effort was to build on both the 2012 Phase 1 NIAC research and the analysis and test results produced by Japanese researchers over the past twenty years to assess the potential for spacecraft propulsion applications. The primary objective of the FY13 effort was to create particle-in-cell computer simulations of a TWDEC. Other objectives included construction of a breadboard TWDEC test article, preliminary test calibration of the simulations, and construction of first order power system models to feed into mission architecture analyses with COPERNICUS tools. Due to funding cuts resulting from the FY13 sequestration, only the computer simulations and assembly of the breadboard test article were completed. The simulations, however, are of unprecedented flexibility and precision and were presented at the 2013 AIAA Joint Propulsion Conference. Also, the assembled test article will provide an ion current density two orders of magnitude above that available in previous Japanese experiments, thus enabling the first direct measurements of power generation from a TWDEC for FY14. The proposed FY14 effort will use the test article for experimental validation of the computer simulations and thus complete to a greater fidelity the

  2. Conversation Intention Perception based on Knowledge Base

    Science.gov (United States)

    2014-05-01

    direction of academic research and industry development. The main duty of WI is making use of various web information and knowledge in a professional and...Yi Liu Gastritis Fracture Vomit Pain Bleeding thirst Anti-acid Clarithromycin styptic Aspirin Symptom Medicine Disease 1/117 1/157 1/20

  3. Highly integrated CO2 capture and conversion: Direct synthesis of cyclic carbonates from industrial flue gas

    KAUST Repository

    Barthel, Alexander

    2016-02-08

    Robust and selective catalytic systems based on early transition metal halides (Y, Sc, Zr) and organic nucleophiles were found able to quantitatively capture CO2 from diluted streams via formation of hemicarbonate species and to convert it to cyclic organic carbonates under ambient conditions. This observation was exploited in the direct and selective chemical fixation of flue gas CO2 collected from an industrial exhaust, affording high degrees of CO2 capture and conversion.

  4. Direct photon cross section with conversions at CDF

    OpenAIRE

    CDF collaboration

    2004-01-01

    We present a measurement of the isolated direct photon cross section in p (p) over bar collisions at roots=1.8 TeV and \\eta\\ lt 0.9 using data collected between 1994 and 1995 by the Collider Detector at Fermilab (CDF). The measurement is based on events where the photon converts into an electron-positron pair in the material of the inner detector, resulting in a two track event signature. To remove pi(0)→gammagamma and eta→gammagamma events from the data we use a new background subtraction te...

  5. Rationale for continuing R&D in direct coal conversion to produce high quality transportation fuels

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, R.D.; McIlvried, H.G. [Burns and Roe Services Corp., Pittsburgh, PA (United States); Gray, D. [Mitre Corp, McLean, VA (United States)] [and others

    1995-12-31

    For the foreseeable future, liquid hydrocarbon fuels will play a significant role in the transportation sector of both the United States and the world. Factors favoring these fuels include convenience, high energy density, and the vast existing infrastructure for their production and use. At present the U.S. consumes about 26% of the world supply of petroleum, but this situation is expected to change because of declining domestic production and increasing competition for imports from countries with developing economies. A scenario and time frame are developed in which declining world resources will generate a shortfall in petroleum supply that can be allieviated in part by utilizing the abundant domestic coal resource base. One option is direct coal conversion to liquid transportation fuels. Continued R&D in coal conversion technology will results in improved technical readiness that can significantly reduce costs so that synfuels can compete economically in a time frame to address the shortfall.

  6. Opportunities for Learning-Based Conversations in High School Mathematics

    Science.gov (United States)

    McFeetors, Janelle

    2015-01-01

    Conversations as moments for interpersonal and intimate turning round of ideas for the purpose of growth are well-defined within curriculum inquiry. Interactions among grade 12 students in this study demonstrate the possibility of learning to learn mathematics through conversation. Attending to opportunities for learning-based conversations,…

  7. Polymer Based Nanocomposites for Solar Energy Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Shaheen, S.; Olson, D.; White, M.; Mitchell, W.; Miedaner, A.; Curtis, C.; Rumbles, G.; Gregg, B.; Ginley, D.

    2005-01-01

    Organic semiconductor-based photovoltaic devices offer the promise of low cost photovoltaic technology that can be manufactured via large-scale, roll-to-roll printing techniques. Existing organic photovoltaic devices are currently limited to solar power conversion efficiencies of 3?5%. This is because of poor overlap between the absorption spectrum of the organic chromophores and the solar spectrum, non-ideal band alignment between the donor and acceptor species, and low charge carrier mobilities. To address these issues, we are investigating the development of dendrimeric organic semiconductors that are readily synthesized with high purity. They also benefit from optoelectronic properties, such as band gap and band positions, which can be easily tuned by substituting different chemical groups into the molecule. Additionally, we are developing nanostructured oxide/conjugated polymer composite photovoltaics. These composites take advantage of the high electron mobilities attainable in oxide semiconductors and can be fabricated using low-temperature solution-based growth techniques. Here, we discuss the synthesis and preliminary device results of these novel materials and composites.

  8. Combustion and direct energy conversion inside a micro-combustor

    International Nuclear Information System (INIS)

    Lei, Yafeng; Chen, Wei; Lei, Jiang

    2016-01-01

    Highlights: • The flammability range of micro-combustor was broadened with heat recirculation. • The quenching diameter decreased with heat recirculation compared to without recirculation. • The surface areas to volume ratio was the most important parameter affecting the energy conversion efficiency. • The maximum conversion efficiency (3.15%) was achieved with 1 mm inner diameter. - Abstract: Electrical energy can be generated by employing a micro-thermophotovoltaic (TPV) cell which absorbs thermal radiation from combustion taking place in a micro-combustor. The stability of combustion in a micro-combustor is essential for operating a micro-power system using hydrogen and hydrocarbon fuels as energy source. To understand the mechanism of sustaining combustion within the quenching distance of fuel, this study proposed an annular micro combustion tube with recirculation of exhaust heat. To explore the feasibility of combustion in the micro annular tube, the parameters influencing the combustion namely, quenching diameter, and flammability were studied through numerical simulation. The results indicated that combustion could be realized in micro- combustor using heat recirculation. Following results were obtained from simulation. The quenching diameter reduced from 1.3 mm to 0.9 mm for heat recirculation at equivalence ratio of 1; the lean flammability was 2.5%–5% lower than that of without heat recirculation for quenching diameters between 2 mm and 5 mm. The overall energy conversion efficiency varied at different inner diameters. A maximum efficiency of 3.15% was achieved at an inner diameter of 1 mm. The studies indicated that heat recirculation is an effective strategy to maintain combustion and to improve combustion limits in micro-scale system.

  9. An AC/AC Direct Power Conversion Topology Having Multiple Power Grid Connections with Adjustable Loading

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede

    2004-01-01

    these fraction power will be a necessary feature on a deregulated energy market. This paper presents a new topology of a power converter based on the Direct Power Conversion concept, which is able to connect to multiple grids and provide complete decoupling between without circulating power between the grids......Normally, a power converter has one supply port to connect to the power grid and one or multiple output ports to connect to AC loads that require variable voltage and variable frequency. As the trend on the energy market is towards deregulation, new converter topologies are needed to allow...

  10. Direct conversion of cellulose to glycolic acid with a phosphomolybdic acid catalyst in a water medium

    KAUST Repository

    Zhang, Jizhe

    2012-08-03

    Direct conversion of cellulose to fine chemicals has rarely been achieved. We describe here an eco-benign route for directly converting various cellulose-based biomasses to glycolic acid in a water medium and oxygen atmosphere in which heteromolybdic acids act as multifunctional catalysts to catalyze the hydrolysis of cellulose, the fragmentation of monosaccharides, and the selective oxidation of fragmentation products. With commercial α-cellulose powder as the substrate, the yield of glycolic acid reaches 49.3%. This catalytic system is also effective with raw cellulosic biomass, such as bagasse or hay, as the starting materials, giving rise to remarkable glycolic acid yields of ∼30%. Our heteropoly acid-based catalyst can be recovered in solid form after reaction by distilling out the products and solvent for reuse, and it exhibits consistently high performance in multiple reaction runs. © 2012 American Chemical Society.

  11. Zr-based conversion coatings for multi-metal substrates

    NARCIS (Netherlands)

    Cerezo Palacios, J.M.

    2015-01-01

    In this PhD work, a new surface treatment based on the application of Zr-based conversion coatings by immersion in a Cu containing Zr-based conversion solution was investigated as a replacement of the traditional phosphating process for the automotive industry. Nowadays most of the cars are made of

  12. Direct UV written Michelson interferometer for RZ signal generation using phase-to-intensity modulation conversion

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Geng, Yan; Zsigri, Beata

    2005-01-01

    An integrated Michelson delay interferometer structure making use of waveguide gratings as reflective elements is proposed and fabricated by direct ultraviolet writing. Successful return-to-zero alternate-mark-inversion signal generation using phase-to-intensity modulation conversion...

  13. Direct conversion Si and CdZnTe detectors for digital mammography

    CERN Document Server

    Yin Shi Shi; Maeding, D; Mainprize, J; Mawdsley, G; Yaffe, M J; Gordon, E E; Hamilton, W J

    2000-01-01

    Hybrid pixel detector arrays that convert X-rays directly into charge signals are under development at NOVA for application to digital mammography. This technology also has wide application possibilities in other fields of radiology or in industrial imaging, nondestructive evaluation (NDE) and nondestructive inspection (NDI). These detectors have potentially superior properties compared to either emulsion-based film-screen systems which has nonlinear response to X-rays, or phosphor-based detectors in which there is an intermediate step of X-ray to light photon conversion (Feig and Yaffe, Radiol. Clinics North America 33 (1995) 1205-1230). Potential advantages of direct conversion detectors are high quantum efficiencies (QE) of 98% or higher (for 0.3 mm thick CdZnTe detector with 20 keV X-rays), improved contrast, high sensitivity and low intrinsic noise. These factors are expected to contribute to high detective quantum efficiency (DQE). The prototype hybrid pixel detector developed has 50x50 mu m pixel size,...

  14. The direct conversion of solar energy to electricity

    International Nuclear Information System (INIS)

    1992-01-01

    Half the world's population lives without access to electricity in the rural areas and villages of developing countries. In 1987, world population reached 5 billion and, according to World Bank projections, will increase to over 6 billion in the year 2000 and to over 8 billion in 2025. Such population growth is not uniformly distributed: developed countries have small or negative growth and account for a declining proportion of the world's population. Inasmuch as 95 per cent of the extra inhabitants added each year are in developing countries, rapid population growth in those countries raises serious questions about energy availability for basic human needs and, of course, more broadly about the environment's capacity to support that growth. The present report makes reference to one of the most comprehensively documented conservative scenarios for world energy demand in the year 2020, namely, Energy for a Sustainable World, which assumed that long-term world sustainability must entail constraints on (a) use of natural resources and (b) combustion of fossil fuels resulting in the greenhouse effect. Solar energy is abundant and could become a major source of electricity. Photovoltaics has three particular advantages. It accomplishes sunlight-to-electricity conversion entirely with solid-state electronic components, and with no moving parts required, thereby promising high equipment availability and very low operating and maintenance costs. PV also appears to have very limited environmental impact, with no emissions of the gaseous pollutants associated with fossil-fuel burning and few of the possible local problems associated with some other renewable energy technologies. Finally, the products of photovoltaic technology are modular in construction and can be built up on site in a flexible way, thus minimizing front-end financial risk and investment costs. Figs and tabs

  15. Feasibility of Traveling Wave Direct Energy Conversion of Fission Reaction Fragments

    Science.gov (United States)

    Tarditi, A. G.; George, J. A.; Miley, G. H.; Scott, J. H.

    2013-01-01

    Fission fragment direct energy conversion has been considered in the past for the purpose of increasing nuclear power plant efficiency and for advanced space propulsion. Since the fragments carry electric charge (typically in the order of 20 e) and have 100 MeV-range kinetic energy, techniques utilizing very high-voltage DC electrodes have been considered. This study is focused on a different approach: the kinetic energy of the charged fission fragments is converted into alternating current by means of a traveling wave coupling scheme (Traveling Wave Direct Energy Converter, TWDEC), thereby not requiring the utilization of high voltage technology. A preliminary feasibility analysis of the concept is introduced based on a conceptual level study and on a particle simulation model of the beam dynamics.

  16. Direct measurement of electron beam quality conversion factors using water calorimetry.

    Science.gov (United States)

    Renaud, James; Sarfehnia, Arman; Marchant, Kristin; McEwen, Malcolm; Ross, Carl; Seuntjens, Jan

    2015-11-01

    In this work, the authors describe an electron sealed water calorimeter (ESWcal) designed to directly measure absorbed dose to water in clinical electron beams and its use to derive electron beam quality conversion factors for two ionization chamber types. A functioning calorimeter prototype was constructed in-house and used to obtain reproducible measurements in clinical accelerator-based 6, 9, 12, 16, and 20 MeV electron beams. Corrections for the radiation field perturbation due to the presence of the glass calorimeter vessel were calculated using Monte Carlo (MC) simulations. The conductive heat transfer due to dose gradients and nonwater materials was also accounted for using a commercial finite element method software package. The relative combined standard uncertainty on the ESWcal dose was estimated to be 0.50% for the 9-20 MeV beams and 1.00% for the 6 MeV beam, demonstrating that the development of a water calorimeter-based standard for electron beams over such a wide range of clinically relevant energies is feasible. The largest contributor to the uncertainty was the positioning (Type A, 0.10%-0.40%) and its influence on the perturbation correction (Type B, 0.10%-0.60%). As a preliminary validation, measurements performed with the ESWcal in a 6 MV photon beam were directly compared to results derived from the National Research Council of Canada (NRC) photon beam standard water calorimeter. These two independent devices were shown to agree well within the 0.43% combined relative uncertainty of the ESWcal for this beam type and quality. Absorbed dose electron beam quality conversion factors were measured using the ESWcal for the Exradin A12 and PTW Roos ionization chambers. The photon-electron conversion factor, kecal, for the A12 was also experimentally determined. Nonstatistically significant differences of up to 0.7% were found when compared to the calculation-based factors listed in the AAPM's TG-51 protocol. General agreement between the relative

  17. Study on the Feasibility of Direct Fusion Energy Conversion for Deep-Space Propulsion

    Science.gov (United States)

    Tarditi, Alfonso G.; Miley, George H.; Scott, John H.

    2012-10-01

    A significant change in the current space mission capabilities can be achieved with a highly efficient integration of a fusion energy source with an advanced space propulsion thruster, both with low specific mass. With aneutronic nuclear fusion as the high-density primary energy source, this study considers first electric energy extraction from the fusion reaction products via direct energy conversion to recirculate power as required for the operation of the fusion core. Then the beam of remaining reaction products is conditioned to achieve the optimal thrust and specific impulse for the mission. The research is specifically focused on two key issues: (i) Efficiency improvement of a Traveling Wave Direct Energy Converter (TWDEC, [1]) by achieving a higher ion beam density and optimization of the electrode coupling and of the neutralizing electron flow. (ii) A fast-particle kinetic energy-to-thrust conversion process based on collective interaction between ion bunches well separated in space [2]. Computer simulation results and a design for a basic physics experiment currently under development are reported. [4pt] [1] H. Momota et al., Fus. Tech., 35, 60(1999)[0pt] [2] A. G. Tarditi et al. Proc. NETS 2012 Conf., Woodlands, TX (2012)

  18. Direct Solid-State Conversion of Recyclable Metals and Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kiran Manchiraju

    2012-03-27

    Friction Stir Extrusion (FSE) is a novel energy-efficient solid-state material synthesis and recycling technology capable of producing large quantity of bulk nano-engineered materials with tailored, mechanical, and physical properties. The novelty of FSE is that it utilizes the frictional heating and extensive plastic deformation inherent to the process to stir, consolidate, mechanically alloy, and convert the powders, chips, and other recyclable feedstock materials directly into useable product forms of highly engineered materials in a single step (see Figure 1). Fundamentally, FSE shares the same deformation and metallurgical bonding principles as in the revolutionary friction stir welding process. Being a solid-state process, FSE eliminates the energy intensive melting and solidification steps, which are necessary in the conventional metal synthesis processes. Therefore, FSE is highly energy-efficient, practically zero emissions, and economically competitive. It represents a potentially transformational and pervasive sustainable manufacturing technology for metal recycling and synthesis. The goal of this project was to develop the technological basis and demonstrate the commercial viability of FSE technology to produce the next generation highly functional electric cables for electricity delivery infrastructure (a multi-billion dollar market). Specific focus of this project was to (1) establish the process and material parameters to synthesize novel alloys such as nano-engineered materials with enhanced mechanical, physical, and/or functional properties through the unique mechanical alloying capability of FSE, (2) verifying the expected major energy, environmental, and economic benefits of FSE technology for both the early stage 'showcase' electric cable market and the anticipated pervasive future multi-market applications across several industry sectors and material systems for metal recycling and sustainable manufacturing.

  19. Direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-07-01

    This paper discusses the advantages and problems when implementing direct energy conversion switching-mode audio power amplifiers. It is shown that the total integration of the power supply and Class D audio power amplifier into one compact direct converter can simplify design, increase efficiency and integration level, reduce product volume and lower its cost. As an example, the principle of operation and the measurements made on a direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp are presented. (au)

  20. Direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2005-01-01

    This paper discusses the advantages and problems when implementing direct energy conversion switching-mode audio power amplifiers. It is shown that the total integration of the power supply and Class D audio power amplifier into one compact direct converter can simplify the design, increase effic...... efficiency, reduce the product volume and lower its cost. As an example, the principle of operation and the measurements made on a direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp are presented....

  1. A study on direct energy conversion systems for fast reactors

    International Nuclear Information System (INIS)

    Brown, Neil; Stoner, Joseph; Sayre, Edwin

    2001-11-01

    An innovative conceptual design of a thermoelectric generator for a terrestrial power system has been developed and evaluated. The concept is based on experience gained during the development of the SP-100 lithium cooled nuclear power system for space application. In place of the SP-100 planner multi-couple cell a radial arrangement of the thermocouples is used to build the thermoelectric cell used in the generator. A conceptual approach for integrating the cell into a tubular element that can be fabricated into a power converter heat exchanger module was evaluated. A method for fabricating the cell, tubular assemblies of ten cells and the converter modules has also been developed. Using the module conceptual design, the thermal-electrical performance of several systems was evaluated. The systems evaluated were assumed to operate with primary coolant at 900degC, 550degC and 600degC. System arrangements and size and thermal efficiencies were established for the first two operating temperatures at power level of 1.7 and 20MWe. It was assumed they used a thermoelectric material with a projected value for the figure of merit, ZT, of 3.0. The systems were also evaluated assuming a ZT of 0.95 for thermoelectric components operating at the lower temperature. The 600degC system was sized for 1MWe assuming a thermoelectric material figure of merit of 0.95. The ZT value of 3.0 is very speculative while the value of 0.95 may be achieved with currently available materials. System efficiencies between 8.2 and 24.8% were calculated and it estimated that it would require arrays of 86 to 3560 of the standard modules for power levels from 1MWe to 20MWe respectively. These systems would cover areas of 6000 to 62,500 square feet The key element in the conceptual design is the innovative thermoelectric cell. A logical next step in development of terrestrial thermoelectric converters for application to high temperature reactors is the detailed design and testing of this cell. A useful

  2. A Direct Power Electronic Conversion Topology for Multi-Drive Applications

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede

    2002-01-01

    In this paper, a two-stage converter topology consisting of a three-phase to two-phase matrix converter directly linked to a Voltage Source Inverter (VSI) that provides Direct Power Electronic Conversion (DPEC) is analysed. A new topology for multi-drive applications is proposed where several VSI...... stages are directly linked to a rectification stage without using DC-link capacitors, providing similar performance as a matrix converter: sinusoidal input currents and bi-directional power flow.......In this paper, a two-stage converter topology consisting of a three-phase to two-phase matrix converter directly linked to a Voltage Source Inverter (VSI) that provides Direct Power Electronic Conversion (DPEC) is analysed. A new topology for multi-drive applications is proposed where several VSI...

  3. Conversion to biofuel based heating systems - local environmental effects

    International Nuclear Information System (INIS)

    Jonsson, Anna

    2003-01-01

    with electricity heating and one area with a large amount of small scale wood burning for heating has been investigated in each municipality. The studied heating systems for conversion are connected to a small-scale district heating system, based on bio fuels, and conversion to pellet techniques. The case studies has been performed as following: Investigation of energy needed for heating; Identification of possible heating systems; A brief assessment of the air quality situation. The contribution of the air pollutants NO x , PM 10 and benzene from bio fuel combustion has been investigated by dispersion calculations in the model ALARM. Wind direction, intensity, temperature and topography are taken into account when making the calculations. Other factors considered are chimney height, diameter, flue gas temperature and width of ambient buildings. An example of an application of the results in a geographical information system has also been made. None of the studied housing areas has shown to be unsuitable for combustion of bio fuels. The national threshold values for the studied air pollutants has not been exceeded after a conversion to studied heating systems. The district heating systems gave lower emissions than pellet techniques but other than that there was no significant differences. The most notably difference was seen between different kind of boilers. Old boilers gave far more emissions than more modern models. In these areas that today have a large supply of heat from small scale wood burning in old boilers, the levels of the studied air pollutants are relatively high. A conversion to pellet techniques show a significant decrease in these levels. As the differences between district heating systems and pellet techniques was low, a suitable heating system has been chosen after the heating density. The limit where it is profitable to connect a housing area to a district heating system has been set at 30 kWh/m 2 /yr

  4. An evaluation of unit-based ethics conversations.

    Science.gov (United States)

    Wocial, Lucia D; Hancock, Maureen; Bledsoe, Patricia D; Chamness, Amy R; Helft, Paul R

    2010-01-01

    Unit-based ethics conversations (UBECs) provide nurses with an opportunity for meaningful conversation about the ethical issues they face in routine clinical practice. The goal of the program is to increase participants' abilities and confidence in dealing with ethically challenging situations. This article reviews results from a formal evaluation of UBECs at one organization. The results of this evaluation suggest the UBEC program provides a transformational ethics experience for nurses.

  5. OTDM-WDM Conversion Based on Time-Domain Optical Fourier Transformation with Spectral Compression

    DEFF Research Database (Denmark)

    Mulvad, Hans Christian Hansen; Palushani, Evarist; Galili, Michael

    2011-01-01

    We propose a scheme enabling direct serial-to-parallel conversion of OTDM data tributaries onto a WDM grid, based on optical Fourier transformation with spectral compression. Demonstrations on 320 Gbit/s and 640 Gbit/s OTDM data are shown.......We propose a scheme enabling direct serial-to-parallel conversion of OTDM data tributaries onto a WDM grid, based on optical Fourier transformation with spectral compression. Demonstrations on 320 Gbit/s and 640 Gbit/s OTDM data are shown....

  6. Simulating seasonal patterns of increased greenhouse crop production by conversion of direct radiation into diffuse radiation

    NARCIS (Netherlands)

    Jongschaap, R.E.E.; Dueck, T.A.; Hemming, S.; Marcelis, L.F.M.; Marissen, A.

    2006-01-01

    The conversion of direct solar photosynthetically active radiation (PARDir) into diffuse radiation (PARDif) and its effects on greenhouse crop production were analyzed with simulation models. PARDir can be converted into PARDif by increasing the haze of greenhouse covers with a minimal loss of

  7. Capability of the Direct Dimethyl Ether Synthesis Process for the Conversion of Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Ainara Ateka

    2018-04-01

    Full Text Available The direct synthesis of dimethyl ether (DME is an ideal process to achieve the environmental objective of CO2 conversion together with the economic objective of DME production. The effect of the reaction conditions (temperature, pressure, space time and feed composition (ternary mixtures of H2 + CO + CO2 with different CO2/CO and H2/COx molar ratios on the reaction indices (COx conversion, product yield and selectivity, CO2 conversion has been studied by means of experiments carried out in a fixed-bed reactor, with a CuO-ZnO-MnO/SAPO-18 catalyst, in order to establish suitable ranges of operating conditions for enhancing the individual objectives of CO2 conversion and DME yield. The optimums of these two objectives are achieved in opposite conditions, and for striking a good balance between both objectives, the following conditions are suitable: 275–300 °C; 20–30 bar; 2.5–5 gcat h (molC−1 and a H2/COx molar ratio in the feed of 3. CO2/CO molar ratio in the feed is of great importance. Ratios below 1/3 are suitable for enhancing DME production, whereas CO2/CO ratios above 1 improve the conversion of CO2. This conversion of CO2 in the overall process of DME synthesis is favored by the reverse water gas shift equation, since CO is more active than CO2 in the methanol synthesis reaction.

  8. Direct Conversion of Free Space Millimeter Waves to Optical Domain by Plasmonic Modulator Antenna.

    Science.gov (United States)

    Salamin, Yannick; Heni, Wolfgang; Haffner, Christian; Fedoryshyn, Yuriy; Hoessbacher, Claudia; Bonjour, Romain; Zahner, Marco; Hillerkuss, David; Leuchtmann, Pascal; Elder, Delwin L; Dalton, Larry R; Hafner, Christian; Leuthold, Juerg

    2015-12-09

    A scheme for the direct conversion of millimeter and THz waves to optical signals is introduced. The compact device consists of a plasmonic phase modulator that is seamlessly cointegrated with an antenna. Neither high-speed electronics nor electronic amplification is required to drive the modulator. A built-in enhancement of the electric field by a factor of 35,000 enables the direct conversion of millimeter-wave signals to the optical domain. This high enhancement is obtained via a resonant antenna that is directly coupled to an optical field by means of a plasmonic modulator. The suggested concept provides a simple and cost-efficient alternative solution to conventional schemes where millimeter-wave signals are first converted to the electrical domain before being up-converted to the optical domain.

  9. Baseband I/Q regeneration Method for Direct Conversion Receiver to nullify effect of I/Q mismatch

    Directory of Open Access Journals (Sweden)

    M. Shah

    2016-11-01

    Full Text Available Direct Conversion Receiver is the choice of the today’s designer for low power compact wireless receiver. DCR is attractive due to low power, small size and highly monolithic integratable structure, but distortions affect its performance.  I/Q mismatch is the one of the major distortion which is responsible for performance degradation.  In this paper, a novel method for Direct Conversion Receiver is suggested, which makes it insensitive to the I/Q mismatch. Here the classical homodyne architecture is modified to nullify effect of I/Q mismatch. The proposed method can be implemented in the Digital Signal Processing (DSP back-end section also.  This feature makes it acceptable in the already designed/functioning classical homodyne architecture based receiver.

  10. Piezoelectric transformer-based high conversion ratio interface for driving dielectric actuator in microrobotic applications

    Directory of Open Access Journals (Sweden)

    Chen Chen

    2016-09-01

    Full Text Available Dielectric actuators are utilized to convert electrical power into mechanical strain with considerable potential in microrobotic applications. However, critical challenges that need to be addressed include high-voltage interface with high conversion ratio, light weight, small size, and high power density. This study proposes a high piezoelectric transformer-based high conversion ratio interface that is integrated with a direct current/direct current high conversion ratio boost stage and a direct current/alternating current high-voltage driving stage. A piezoelectric transformer-based class-E zero voltage switching direct current/direct current interface is controlled by a hybrid pulse frequency modulation and pulse width modulation control strategies to obtain the desired high step-up ratio in the direct current/direct current stage. A half-bridge converter with special digital control algorithm in the direct current/alternating current stage is designed to convert high direct current voltage into arbitrary unipolar signal driving dielectric actuators. A prototype 23.3 g and 4 W interface has been fabricated for experimental validation to verify its ability to drive a 1 kV input dielectric actuator at 5 Hz in microrobotic applications.

  11. Direct conversion of plutonium metal, scrap, residue, and transuranic waste to glass

    International Nuclear Information System (INIS)

    Forsberg, C.W.; Beahm, E.C.; Parker, G.W.; Malling, J.F.; Rudolph, J.

    1995-01-01

    A method for the direct conversion of metals, ceramics, organics, and amorphous solids to borosilicate glass has been invented. The process is called the Glass Material Oxidation and Dissolution System (GMODS). Traditional glass-making processes can convert only oxide materials to glass. However, many wastes contain complex mixtures of metals, ceramics, organics, and amorphous solids. Conversion of such mixtures to oxides followed by their conversion to glass is often impractical. GMODS may create a practical method to convert such mixtures to glass. Plutonium-containing materials (PCMS) exist in many forms, including metals, ceramics, organics, amorphous solids, and mixtures thereof. These PCMs vary from plutonium metal to filters made of metal, organic binders, and glass fibers. For storage and/or disposal of PCMS, it is desirable to convert PCMs to borosilicate glass. Borosilicate glass is the preferred repository waste form for high-level waste (HLW) because of its properties. PCMs converted to a transuranic borosilicate homogeneous glass would easily pass all waste acceptance and storage criteria. Conversion of PCMs to a glass would also simplify safeguards by conversion of heterogeneous PCMs to homogeneous glass. Thermodynamic calculations and proof-of-principle experiments on the GMODS process with cerium (plutonium surrogate), uranium, stainless steel, aluminum, Zircaloy-2, and carbon were successfully conducted. Initial analysis has identified potential flowsheets and equipment. Major unknowns remain, but the preliminary data suggests that GMODS may be a major new treatment option for PCMs

  12. Design of batch audio/video conversion platform based on JavaEE

    Science.gov (United States)

    Cui, Yansong; Jiang, Lianpin

    2018-03-01

    With the rapid development of digital publishing industry, the direction of audio / video publishing shows the diversity of coding standards for audio and video files, massive data and other significant features. Faced with massive and diverse data, how to quickly and efficiently convert to a unified code format has brought great difficulties to the digital publishing organization. In view of this demand and present situation in this paper, basing on the development architecture of Sptring+SpringMVC+Mybatis, and combined with the open source FFMPEG format conversion tool, a distributed online audio and video format conversion platform with a B/S structure is proposed. Based on the Java language, the key technologies and strategies designed in the design of platform architecture are analyzed emphatically in this paper, designing and developing a efficient audio and video format conversion system, which is composed of “Front display system”, "core scheduling server " and " conversion server ". The test results show that, compared with the ordinary audio and video conversion scheme, the use of batch audio and video format conversion platform can effectively improve the conversion efficiency of audio and video files, and reduce the complexity of the work. Practice has proved that the key technology discussed in this paper can be applied in the field of large batch file processing, and has certain practical application value.

  13. Polyaniline (PANi based electrode materials for energy storage and conversion

    Directory of Open Access Journals (Sweden)

    Huanhuan Wang

    2016-09-01

    Full Text Available Polyaniline (PANi as one kind of conducting polymers has been playing a great role in the energy storage and conversion devices besides carbonaceous materials and metallic compounds. Due to high specific capacitance, high flexibility and low cost, PANi has shown great potential in supercapacitor. It alone can be used in fabricating an electrode. However, the inferior stability of PANi limits its application. The combination of PANi and other active materials (carbon materials, metal compounds or other polymers can surpass these intrinsic disadvantages of PANi. This review summarizes the recent progress in PANi based composites for energy storage/conversion, like application in supercapacitors, rechargeable batteries, fuel cells and water hydrolysis. Besides, PANi derived nitrogen-doped carbon materials, which have been widely employed as carbon based electrodes/catalysts, are also involved in this review. PANi as a promising material for energy storage/conversion is deserved for intensive study and further development.

  14. Thermionic Energy Conversion Based on Graphene van der Waals Heterostructures

    Science.gov (United States)

    Liang, Shi-Jun; Liu, Bo; Hu, Wei; Zhou, Kun; Ang, L. K.

    2017-04-01

    Seeking for thermoelectric (TE) materials with high figure of merit (or ZT), which can directly converts low-grade wasted heat (400 to 500 K) into electricity, has been a big challenge. Inspired by the concept of multilayer thermionic devices, we propose and design a solid-state thermionic devices (as a power generator or a refrigerator) in using van der Waals (vdW) heterostructure sandwiched between two graphene electrodes, to achieve high energy conversion efficiency in the temperature range of 400 to 500 K. The vdW heterostructure is composed of suitable multiple layers of transition metal dichalcogenides (TMDs), such as MoS2, MoSe2, WS2 and WSe2. From our calculations, WSe2 and MoSe2 are identified as two ideal TMDs (using the reported experimental material’s properties), which can harvest waste heat at 400 K with efficiencies about 7% to 8%. To our best knowledge, this design is the first in combining the advantages of graphene electrodes and TMDs to function as a thermionic-based device.

  15. Shear Alfven wave excitation by direct antenna coupling and fast wave resonant mode conversion

    International Nuclear Information System (INIS)

    Borg, G.G.

    1994-01-01

    Antenna coupling to the shear Alfven wave by both direct excitation and fast wave resonant mode conversion is modelled analytically for a plasma with a one dimensional linear density gradient. We demonstrate the existence of a shear Alfven mode excited directly by the antenna. For localised antennas, this mode propagates as a guided beam along the steady magnetic field lines intersecting the antenna. Shear Alfven wave excitation by resonant mode conversion of a fast wave near the Alfven resonance layer is also demonstrated and we prove that energy is conserved in this process. We compare the efficiency of these two mechanisms of shear Alfven wave excitation and present a simple analytical formula giving the ratio of the coupled powers. Finally, we discuss the interpretation of some experimental results. 45 refs., 7 figs

  16. Direct Coupling of Thermo- and Photocatalysis for Conversion of CO2 -H2 O into Fuels.

    Science.gov (United States)

    Zhang, Li; Kong, Guoguo; Meng, Yaping; Tian, Jinshu; Zhang, Lijie; Wan, Shaolong; Lin, Jingdong; Wang, Yong

    2017-12-08

    Photocatalytic CO 2 reduction into renewable hydrocarbon solar fuels is considered as a promising strategy to simultaneously address global energy and environmental issues. This study focused on the direct coupling of photocatalytic water splitting and thermocatalytic hydrogenation of CO 2 in the conversion of CO 2 -H 2 O into fuels. Specifically, it was found that direct coupling of thermo- and photocatalysis over Au-Ru/TiO 2 leads to activity 15 times higher (T=358 K; ca. 99 % CH 4 selectivity) in the conversion of CO 2 -H 2 O into fuels than that of photocatalytic water splitting. This is ascribed to the promoting effect of thermocatalytic hydrogenation of CO 2 by hydrogen atoms generated in situ by photocatalytic water splitting. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Direct energy conversion system for D-{sup 3}He fusion

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, Y.; Shu, L.Y.; Momota, H.

    1993-11-01

    A novel and highly efficient direct energy conversion system is proposed for utilizing D-{sup 3}He fueled fusion. In order to convert kinetic energy of ions, we applied a pair of direct energy conversion systems each of which has a cusp-type DEC and a traveling wave DEC (TWDEC). In a cusp-type DEC, electrons are separated from the escaping ions at the first line-cusp and the energy of thermal ion components is converted at the second cusp DEC. The fusion protons go through the cusp-type DEC and arrive at the TWDEC, which principle is similar to `LINAC.` The energy of fusion protons is recovered to electricity with an efficiency of more than 70%. These DECs bring about the high efficient fusion plant. (author).

  18. Direct energy conversion system for D-{sup 3}He fusion

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, Y.; Shu, L.Y.; Momota, H. [National Inst. for Fusion Science, Nagoya (Japan)

    1994-12-31

    A novel and highly efficient direct energy conversion system is proposed for utilizing D-{sup 3}He fueled fusion. In order to convert kinetic energy of ions, we applied a pair of direct energy conversion systems each of which has a cusp-type DEC and a traveling wave DEC (TWDEC). In a cusp-type DEC, electrons are separated from the escaping ions at the first line-cusp and the energy of thermal ion components is converted at the second cusp DEC. The fusion protons go through the cusp-type DEC and arrive at the TWDEC, which principle is similar to `LINAC`. The energy of fusion protons is recovered to electricity with an efficiency of more than 70%. These DECs bring about the high efficient fusion plant. (author).

  19. Direct conversion of methane to higher hydrocarbons using AlBr3-HBr superacid catalyst.

    Science.gov (United States)

    Vasireddy, Sivakumar; Ganguly, Sreemoyee; Sauer, Joe; Cook, Wyndham; Spivey, James J

    2011-01-14

    The direct gas phase catalytic oligomerization of methane at temperatures ≤673 K has been demonstrated using AlBr(3)-HBr superacid. The reaction produces C(2)+ hydrocarbons and hydrogen in a single step at 1 atm in a continuous flow reactor at a nominal residence time of 60 s. The essentially complete conversion of methane appears to be due to protolytic activation of methane in the presence of H(+)AlBr(4)(-).

  20. Screw calciner mechanical direct denitration process for plutonium nitrate to oxide conversion

    International Nuclear Information System (INIS)

    Souply, K.R.; Sperry, W.E.

    1977-01-01

    This report describes a screw calciner direct-denitration process for converting plutonium nitrate to plutonium oxide. The information should be used when making comparisons of alternative plutonium nitrate-to-oxide conversion processes or as a basis for further detailed studies. The report contains process flow sheets with a material balance; a process description; and a discussion of the process including history, advantages and disadvantages, and additional research required

  1. PMBLDCG based stand-alone wind energy conversion system for ...

    African Journals Online (AJOL)

    This paper deals with a permanent magnet brushless DC generator (PMBLDCG) based stand-alone wind energy conversion system (WECS) for small scale power generation. A buck-boost DC-DC converter is used for controlling the PMBLDCG speed to achieve optimum energy output from the wind turbine without sensing ...

  2. Self-oscillating modulators for direct energy conversion audio power amplifiers

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-07-01

    Direct energy conversion audio power amplifier represents total integration of switching-mode power supply and Class D audio power amplifier into one compact stage, achieving high efficiency, high level of integration, low component count and eventually low cost. This paper presents how self-oscillating modulators can be used with the direct switching-mode audio power amplifier to improve its performance by providing fast hysteretic control with high power supply rejection ratio, open-loop stability and high bandwidth. Its operation is thoroughly analyzed and simulated waveforms of a prototype amplifier are presented. (au)

  3. Self-oscillating modulators for direct energy conversion audio power amplifiers

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2005-01-01

    Direct energy conversion audio power amplifier represents total integration of switching-mode power supply and Class D audio power amplifier into one compact stage, achieving high efficiency, high level of integration, low component count and eventually low cost. This paper presents how self......-oscillating modulators can be used with the direct switching-mode audio power amplifier to improve its performance by providing fast hysteretic control with high power supply rejection ratio, open-loop stability and high bandwidth. Its operation is thoroughly analyzed and experimental results from prototype amplifier...

  4. Thermoelectric Oxide Modules (TOMs for the Direct Conversion of Simulated Solar Radiation into Electrical Energy

    Directory of Open Access Journals (Sweden)

    Petr Tomeš

    2010-04-01

    Full Text Available The direct conversion of concentrated high temperature solar heat into electrical energy was demonstrated with a series of four–leg thermoelectric oxide modules (TOM. These temperature stable modules were not yet optimized for high efficiency conversion, but served as proof-of-principle for high temperature conversion. They were constructed by connecting two p- (La1.98Sr0.02CuO4 and two n-type (CaMn0.98Nb0.02O3 thermoelements electrically in series and thermally in parallel. The temperature gradient ΔT was applied by a High–Flux Solar Simulator source (HFSS which generates a spectrum similar to solar radiation. The influence of the graphite layer coated on the hot side of the Al2O3 substrate compared to the uncoated surface on ΔT, Pmax and η was studied in detail. The measurements show an almost linear temperature profile along the thermoelectric legs. The maximum output power of 88.8 mW was reached for a TOM with leg length of 5 mm at ΔT = 622 K. The highest conversion efficiency η was found for a heat flux of 4–8 W cm-2 and the dependence of η on the leg length was investigated.

  5. Direct formation of gasoline hydrocarbons from cellulose by hydrothermal conversion with in situ hydrogen

    International Nuclear Information System (INIS)

    Yin, Sudong; Mehrotra, Anil Kumar; Tan, Zhongchao

    2012-01-01

    A new process based on aqueous-phase dehydration/hydrogenation (APD/H) has been developed to directly produce liquid alkanes (C 7–9 ), which are the main components of fossil gasoline, from cellulose in one single batch reactor without the consumption of external hydrogen (H 2 ). In this new process, part of the cellulose is first converted to in situ H 2 by steam reforming (SR) in the steam gas phase mainly; and, in the liquid water phase, cellulose is converted to an alkane precursor, such as 5-(hydroxymethyl)furfural (HMF). In the final reaction step, in situ H 2 reacts with HMF to form liquid alkanes through APD/H. Accordingly, this new process has been named SR(H 2 )-APD/H. Experimental results show that the volumetric ratio of the reactor headspace to the reactor (H/R) and an initial weakly alkaline condition are the two key parameters for SR(H 2 )-APD/H. With proper H/R ratios (e.g., 0.84) and initial weakly alkaline conditions (e.g., pH = 7.5), liquid alkanes are directly formed from the SR(H 2 )-APD/H of cellulose using in situ H 2 instead of external H 2 . In this study, compared with pyrolysis and hydrothermal liquefaction of cellulose at the same temperatures with same retetion time, SR(H 2 )-APD/H greatly increased the liquid alkane yields, by approximately 700 times and 35 times, respectively. Based on this process, direct formation of fossil gasoline from renewable biomass resources without using external H 2 becomes possible. -- Highlights: ► A process of producing gasoline alkanes from cellulose was proposed and studied. ► Alkane precursors and in situ H 2 were formed simultaneously in a single reactor. ► Alkanes subsequently formed by reactions between in situ H 2 and alkane precursors. ► The yields were 700 and 35 times higher than pyrolysis and hydrothermal conversion.

  6. Teaching Medical Students About "The Conversation": An Interactive Value-Based Advance Care Planning Session.

    Science.gov (United States)

    Lum, Hillary D; Dukes, Joanna; Church, Skotti; Abbott, Jean; Youngwerth, Jean M

    2018-02-01

    Advance care planning (ACP) promotes care consistent with patient wishes. Medical education should teach how to initiate value-based ACP conversations. To develop and evaluate an ACP educational session to teach medical students a value-based ACP process and to encourage students to take personal ACP action steps. Groups of third-year medical students participated in a 75-minute session using personal reflection and discussion framed by The Conversation Starter Kit. The Conversation Project is a free resource designed to help individuals and families express their wishes for end-of-life care. One hundred twenty-seven US third-year medical students participated in the session. Student evaluations immediately after the session and 1 month later via electronic survey. More than 90% of students positively evaluated the educational value of the session, including rating highly the opportunities to reflect on their own ACP and to use The Conversation Starter Kit. Many students (65%) reported prior ACP conversations. After the session, 73% reported plans to discuss ACP, 91% had thought about preferences for future medical care, and 39% had chosen a medical decision maker. Only a minority had completed an advance directive (14%) or talked with their health-care provider (1%). One month later, there was no evidence that the session increased students' actions regarding these same ACP action steps. A value-based ACP educational session using The Conversation Starter Kit successfully engaged medical students in learning about ACP conversations, both professionally and personally. This session may help students initiate conversations for themselves and their patients.

  7. Conversion of Low-Rank Wyoming Coals into Gasoline by Direct Liquefaction

    Energy Technology Data Exchange (ETDEWEB)

    Polyakov, Oleg

    2013-12-31

    Under the cooperative agreement program of DOE and funding from Wyoming State’s Clean Coal Task Force, Western Research Institute and Thermosolv LLC studied the direct conversion of Wyoming coals and coal-lignin mixed feeds into liquid fuels in conditions highly relevant to practice. During the Phase I, catalytic direct liquefaction of sub-bituminous Wyoming coals was investigated. The process conditions and catalysts were identified that lead to a significant increase of desirable oil fraction in the products. The Phase II work focused on systematic study of solvothermal depolymerization (STD) and direct liquefaction (DCL) of carbonaceous feedstocks. The effect of the reaction conditions (the nature of solvent, solvent/lignin ratio, temperature, pressure, heating rate, and residence time) on STD was investigated. The effect of a number of various additives (including lignin, model lignin compounds, lignin-derivable chemicals, and inorganic radical initiators), solvents, and catalysts on DCL has been studied. Although a significant progress has been achieved in developing solvothermal depolymerization, the side reactions – formation of considerable amounts of char and gaseous products – as well as other drawbacks do not render aqueous media as the most appropriate choice for commercial implementation of STD for processing coals and lignins. The trends and effects discovered in DCL point at the specific features of liquefaction mechanism that are currently underutilized yet could be exploited to intensify the process. A judicious choice of catalysts, solvents, and additives might enable practical and economically efficient direct conversion of Wyoming coals into liquid fuels.

  8. Test Results from a Direct Drive Gas Reactor Simulator Coupled to a Brayton Power Conversion Unit

    Science.gov (United States)

    Hervol, David S.; Briggs, Maxwell H.; Owen, Albert K.; Bragg-Sitton, Shannon M.; Godfroy, Thomas J.

    2010-01-01

    Component level testing of power conversion units proposed for use in fission surface power systems has typically been done using relatively simple electric heaters for thermal input. These heaters do not adequately represent the geometry or response of proposed reactors. As testing of fission surface power systems transitions from the component level to the system level it becomes necessary to more accurately replicate these reactors using reactor simulators. The Direct Drive Gas-Brayton Power Conversion Unit test activity at the NASA Glenn Research Center integrates a reactor simulator with an existing Brayton test rig. The response of the reactor simulator to a change in Brayton shaft speed is shown as well as the response of the Brayton to an insertion of reactivity, corresponding to a drum reconfiguration. The lessons learned from these tests can be used to improve the design of future reactor simulators which can be used in system level fission surface power tests.

  9. Design of video interface conversion system based on FPGA

    Science.gov (United States)

    Zhao, Heng; Wang, Xiang-jun

    2014-11-01

    This paper presents a FPGA based video interface conversion system that enables the inter-conversion between digital and analog video. Cyclone IV series EP4CE22F17C chip from Altera Corporation is used as the main video processing chip, and single-chip is used as the information interaction control unit between FPGA and PC. The system is able to encode/decode messages from the PC. Technologies including video decoding/encoding circuits, bus communication protocol, data stream de-interleaving and de-interlacing, color space conversion and the Camera Link timing generator module of FPGA are introduced. The system converts Composite Video Broadcast Signal (CVBS) from the CCD camera into Low Voltage Differential Signaling (LVDS), which will be collected by the video processing unit with Camera Link interface. The processed video signals will then be inputted to system output board and displayed on the monitor.The current experiment shows that it can achieve high-quality video conversion with minimum board size.

  10. Experimental Investigations of Direct and Converse Flexoelectric Effect in Bilayer Lipid Membranes.

    Science.gov (United States)

    Todorov, Angelio Todorov

    Flexoelectric coefficients (direct and converse), electric properties (capacitance and resistivity) and mechanical properties (thickness and elastic coefficients) have been determined for bilayer lipid membranes (BLMs) prepared from egg yolk lecithin (EYL), glycerol monoleate (GMO), phosphatidyl choline (PC) and phosphatidyl serine (PS) as a function of frequency, pH and surface charge modifiers. Direct flexoelectric effect manifested itself in the development of microvolt range a.c. potential (U_{f}) upon subjecting one side of a BLM to an oscillating hydrostatic pressure, in the 100-1000 Hz range. Operationally, the flexoelectric coefficient (f) is expressed by the ratio between U_{f} and the change of curvature (c) which accompanied the flexing of the membrane. Membrane curvature was determined by means of either the electric method (capacitance microphone effect) or by the newly developed method of stroboscopic interferometry. Real-time stroboscopic interferometry coupled with simultaneous electric measurements, provided a direct method for the determination of f. Two different frequency regimes of f were recognized. At low frequencies (free mobility of the surfactant, f-values of 24.1 times 10^{-19} and 0.87 times 10^ {-19} Coulombs were obtained for PC and GMO BLMs. At high frequencies (>300 Hz), associated with blocked mobility of the surfactant, f-values of 16.5 times 10^ {-19} and 0.30 times 10^{-19} Coulombs were obtained for PC and GMO BLMs. The theoretically calculated value for the GMO BLM oscillating at high frequency (0.12 times 10^{-19 } Coulombs) agreed well with that determined experimentally (0.3 times 10 ^{-19} Coulombs). For charged bovine brain PS BLM the observed flexocoefficient was f = 4.0 times 10^{ -18} Coulombs. Converse flexoelectric effect manifested itself in voltage-induced BLM curvature. Observations were carried out on uranyl acetate (UA) stabilized PS BLM under a.c. excitation. Frequency dependence of f was revealed by means of

  11. Calorimetric Measurement for Internal Conversion Efficiency of Photovoltaic Cells/Modules Based on Electrical Substitution Method

    Science.gov (United States)

    Saito, Terubumi; Tatsuta, Muneaki; Abe, Yamato; Takesawa, Minato

    2018-02-01

    We have succeeded in the direct measurement for solar cell/module internal conversion efficiency based on a calorimetric method or electrical substitution method by which the absorbed radiant power is determined by replacing the heat absorbed in the cell/module with the electrical power. The technique is advantageous in that the reflectance and transmittance measurements, which are required in the conventional methods, are not necessary. Also, the internal quantum efficiency can be derived from conversion efficiencies by using the average photon energy. Agreements of the measured data with the values estimated from the nominal values support the validity of this technique.

  12. Defining the Minimal Factors Required for Erythropoiesis through Direct Lineage Conversion

    Directory of Open Access Journals (Sweden)

    Sandra Capellera-Garcia

    2016-06-01

    Full Text Available Erythroid cell commitment and differentiation proceed through activation of a lineage-restricted transcriptional network orchestrated by a group of well characterized genes. However, the minimal set of factors necessary for instructing red blood cell (RBC development remains undefined. We employed a screen for transcription factors allowing direct lineage reprograming from fibroblasts to induced erythroid progenitors/precursors (iEPs. We show that Gata1, Tal1, Lmo2, and c-Myc (GTLM can rapidly convert murine and human fibroblasts directly to iEPs. The transcriptional signature of murine iEPs resembled mainly that of primitive erythroid progenitors in the yolk sac, whereas addition of Klf1 or Myb to the GTLM cocktail resulted in iEPs with a more adult-type globin expression pattern. Our results demonstrate that direct lineage conversion is a suitable platform for defining and studying the core factors inducing the different waves of erythroid development.

  13. Graphene Paper Based Nanomaterials for Electrochemical Sensing and Energy Conversion

    DEFF Research Database (Denmark)

    Zhang, Minwei

    Graphene has emerged as a highly interesting material since it was experimentally isolated for the first timein 2004. This single-atom-thick nanosheet consisting of carbon atoms arrayed in a honeycomb pattern,displays outstanding physicochemical properties, including as an excellent conductor...... of heat and electricity,large specific surface area, and high mechanical strength. Therefore, graphene based materials are expected to have great potential for use in the fields of sensors, catalysis, and as electrode materials for energy storage and conversion. In order to link practical applications...... and energy technologies. This PhD project is devoted to the synthesis, characterization and applications of graphene paper based nanomaterials for electrochemical sensors and energy conversion. The thesis is divided into three parts with 8 chapters in total. In Chapter 1, we provide an overview...

  14. Developing Low-Intermediate Temperature Fuel Cells for Direct Conversion of Methane to Methanol Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Torabi, A.; Barton, J.; Willman, C.; Ghezel-Ayagh, H.; Li, N.; Poozhikunnath, A.; Maric, R.; Marina, O. A.

    2016-04-26

    The objective of this project is development of a durable, low-cost, and high performance Low Temperature Solid Oxide Fuel Cell (LT-SOFC) for direct conversion of methane to methanol and other liquids, characterized by: a) operating temperature < 500oC, b) current density of > 100 mA/cm2 in liquid hydrocarbon production mode, c) continuous operation of > 100 h, d) cell area >100 cm2, e) cell cost per rate of product output < 100,000/bpd, f) process intensity of > 0.1 bpd/ft3, g) product yield and carbon efficiency > 50%, and h) volumetric output per cell > 30 L/day.

  15. Food waste-to-energy conversion technologies: current status and future directions.

    Science.gov (United States)

    Pham, Thi Phuong Thuy; Kaushik, Rajni; Parshetti, Ganesh K; Mahmood, Russell; Balasubramanian, Rajasekhar

    2015-04-01

    Food waste represents a significantly fraction of municipal solid waste. Proper management and recycling of huge volumes of food waste are required to reduce its environmental burdens and to minimize risks to human health. Food waste is indeed an untapped resource with great potential for energy production. Utilization of food waste for energy conversion currently represents a challenge due to various reasons. These include its inherent heterogeneously variable compositions, high moisture contents and low calorific value, which constitute an impediment for the development of robust, large scale, and efficient industrial processes. Although a considerable amount of research has been carried out on the conversion of food waste to renewable energy, there is a lack of comprehensive and systematic reviews of the published literature. The present review synthesizes the current knowledge available in the use of technologies for food-waste-to-energy conversion involving biological (e.g. anaerobic digestion and fermentation), thermal and thermochemical technologies (e.g. incineration, pyrolysis, gasification and hydrothermal oxidation). The competitive advantages of these technologies as well as the challenges associated with them are discussed. In addition, the future directions for more effective utilization of food waste for renewable energy generation are suggested from an interdisciplinary perspective. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Genome and Transcriptome of Clostridium phytofermentans, Catalyst for the Direct Conversion of Plant Feedstocks to Fuels

    Science.gov (United States)

    Petit, Elsa; Coppi, Maddalena V.; Hayes, James C.; Tolonen, Andrew C.; Warnick, Thomas; Latouf, William G.; Amisano, Danielle; Biddle, Amy; Mukherjee, Supratim; Ivanova, Natalia; Lykidis, Athanassios; Land, Miriam; Hauser, Loren; Kyrpides, Nikos; Henrissat, Bernard; Lau, Joanne; Schnell, Danny J.; Church, George M.; Leschine, Susan B.; Blanchard, Jeffrey L.

    2015-01-01

    Clostridium phytofermentans was isolated from forest soil and is distinguished by its capacity to directly ferment plant cell wall polysaccharides into ethanol as the primary product, suggesting that it possesses unusual catabolic pathways. The objective of the present study was to understand the molecular mechanisms of biomass conversion to ethanol in a single organism, Clostridium phytofermentans, by analyzing its complete genome and transcriptome during growth on plant carbohydrates. The saccharolytic versatility of C. phytofermentans is reflected in a diversity of genes encoding ATP-binding cassette sugar transporters and glycoside hydrolases, many of which may have been acquired through horizontal gene transfer. These genes are frequently organized as operons that may be controlled individually by the many transcriptional regulators identified in the genome. Preferential ethanol production may be due to high levels of expression of multiple ethanol dehydrogenases and additional pathways maximizing ethanol yield. The genome also encodes three different proteinaceous bacterial microcompartments with the capacity to compartmentalize pathways that divert fermentation intermediates to various products. These characteristics make C. phytofermentans an attractive resource for improving the efficiency and speed of biomass conversion to biofuels. PMID:26035711

  17. Direct conversion of methane to C sub 2 's and liquid fuels

    Energy Technology Data Exchange (ETDEWEB)

    Warren, B.K.; Campbell, K.D.

    1989-11-22

    Objectives of the project are to discover and evaluate novel catalytic systems for the conversion of methane or by-product light hydrocarbon gases either indirectly (through intermediate light gases rich in C{sub 2}'s) or directly to liquid hydrocarbon fuels, and to evaluate, from an engineering perspective, different conceptualized schemes. The approach is to carry out catalyst testing on several specific classes of potential catalysts for the conversion of methane selectively to C{sub 2} products. Promoted metal oxide catalysts were tested. Several of these exhibited similar high ethylene to ethane ratios and low carbon dioxide to carbon monoxide ratios observed for the NaCl/{alpha}-alumina catalyst system reported earlier. Research on catalysts containing potentially activated metals began with testing of metal molecular sieves. Silver catalysts were shown to be promising as low temperature catalysts. Perovskites were tested as potential methane coupling catalysts. A layered perovskite (K{sub 2}La{sub 2}Ti{sub 3}O{sub 10}) gave the highest C{sub 2} yield. Work continued on the economic evaluation of a hypothetical process converting methane to ethylene. An engineering model of the methane coupling system has been prepared. 47 refs., 17 figs., 57 tabs.

  18. Conversion efficiency of skutterudite-based thermoelectric modules.

    Science.gov (United States)

    Salvador, James R; Cho, Jung Y; Ye, Zuxin; Moczygemba, Joshua E; Thompson, Alan J; Sharp, Jeffrey W; Koenig, Jan D; Maloney, Ryan; Thompson, Travis; Sakamoto, Jeffrey; Wang, Hsin; Wereszczak, Andrew A

    2014-06-28

    Presently, the only commercially available power generating thermoelectric (TE) modules are based on bismuth telluride (Bi2Te3) alloys and are limited to a hot side temperature of 250 °C due to the melting point of the solder interconnects and/or generally poor power generation performance above this point. For the purposes of demonstrating a TE generator or TEG with higher temperature capability, we selected skutterudite based materials to carry forward with module fabrication because these materials have adequate TE performance and are mechanically robust. We have previously reported the electrical power output for a 32 couple skutterudite TE module, a module that is type identical to ones used in a high temperature capable TEG prototype. The purpose of this previous work was to establish the expected power output of the modules as a function of varying hot and cold side temperatures. Recent upgrades to the TE module measurement system built at the Fraunhofer Institute for Physical Measurement Techniques allow for the assessment of not only the power output, as previously described, but also the thermal to electrical energy conversion efficiency. Here we report the power output and conversion efficiency of a 32 couple, high temperature skutterudite module at varying applied loading pressures and with different interface materials between the module and the heat source and sink of the test system. We demonstrate a 7% conversion efficiency at the module level when a temperature difference of 460 °C is established. Extrapolated values indicate that 7.5% is achievable when proper thermal interfaces and loading pressures are used.

  19. Test Results From a Direct Drive Gas Reactor Simulator Coupled to a Brayton Power Conversion Unit

    Science.gov (United States)

    Hervol, David S.; Briggs, Maxwell H.; Owen, Albert K.; Bragg-Sitton, Shannon M.

    2009-01-01

    The Brayton Power Conversion Unit (BPCU) located at NASA Glenn Research Center (GRC) in Cleveland, OH is a closed cycle system incorporating a turboaltemator, recuperator, and gas cooler connected by gas ducts to an external gas heater. For this series of tests, the BPCU was modified by replacing the gas heater with the Direct Drive Gas heater or DOG. The DOG uses electric resistance heaters to simulate a fast spectrum nuclear reactor similar to those proposed for space power applications. The combined system thermal transient behavior was the focus of these tests. The BPCU was operated at various steady state points. At each point it was subjected to transient changes involving shaft rotational speed or DOG electrical input. This paper outlines the changes made to the test unit and describes the testing that took place along with the test results.

  20. Direct single to two/three phase power electronic conversion for AC traction applications

    Energy Technology Data Exchange (ETDEWEB)

    Dobrucky, B.; Pavlanin, R.; Pokorny, M. [Zilina Univ. (Slovakia). Faculty of Electrical Engineering

    2008-07-01

    This paper discussed single to 3-phase power electronic converters. Conversion rates were evaluated using a middle frequency transformer with matrix converters. The use of a matrix converter subsystem with a 2-phase orthogonal induction motor was compared with conventional drives as a means of reducing the number of converter power switching elements. The converter was a high voltage modular multilevel converter where the transformer was fed directly by the single phase converter system operating on an AC line voltage. The converter offered sinusoidal input and output harmonics, eliminated the need for a DC link circuit, and decreased the number of switching elements for converters in AC-AC drives. A power active filter was used to improve the harmonic content of the input and output currents. Simulations of the 2-phase matrix converter orthogonal driving concept indicated that the converter can be used to provide solutions for single phase electric traction applications. 21 refs., 15 figs.

  1. Conversational agents for academically productive talk: a comparison of directed and undirected agent interventions

    DEFF Research Database (Denmark)

    Tegos, Stergios; Demetriadis, Stavros N.; Papadopoulos, Pantelis M.

    2016-01-01

    Conversational agents that draw on the framework of academically productive talk (APT) have been lately shown to be effective in helping learners sustain productive forms of peer dialogue in diverse learning settings. Yet, literature suggests that more research is required on how learners respond...... instead of the dyad (D treatment). The results suggest that although both agent intervention methods can improve students’ learning outcomes and dyad in-task performance, the directed one is more effective than the undirected one in enhancing individual domain knowledge acquisition and explicit reasoning....... Furthermore, findings show that the positive effect of the agent on dyad performance is mediated by the frequency of students’ contributions displaying explicit reasoning, while most students perceive agent involvement favorably....

  2. Direct conversion of radioactive and chemical waste containing metals, ceramics, amorphous solids, and organics to glass

    International Nuclear Information System (INIS)

    Forsberg, C.W.; Beahm, E.C.; Parker, G.W.

    1994-01-01

    The Glass Material Oxidation and Dissolution System (CMODS) is a new process for direct conversion of radioactive, mixed, and chemical wastes to glass. The wastes can be in the chemical forms of metals, ceramics, amorphous solids, and organics. GMODS destroys organics and it incorporates heavy metals and radionuclides into a glass. Processable wastes may include miscellaneous spent fuels (SF), SF hulls and hardware, plutonium wastes in different forms, high-efficiency particulate air (HEPA) filters, ion-exchange resins, failed equipment, and laboratory wastes. Thermodynamic calculations indicate theoretical feasibility. Small-scale laboratory experiments (< 100 g per test) have demonstrated chemical laboratory feasibility for several metals. Additional work is needed to demonstrate engineering feasibility

  3. Coordinated Operation of the Electricity and Natural Gas Systems with Bi-directional Energy Conversion

    DEFF Research Database (Denmark)

    Zeng, Qing; Zhang, Baohua; Fang, Jiakun

    2017-01-01

    A coordinated operation of the natural gas and electricity network with bi-directional energy conversion is expected to accommodate high penetration levels of renewables. This work focuses on the unified optimal operation of the integrated natural gas and electricity system considering the network...... constraints in both systems. An iterative method is proposed to deal with the nonlinearity in the proposed model. The models of the natural gas and power system are linearized in every iterative step. Simulation results demonstrate the effectiveness of the approach. Applicability of the proposed method...... is tested in the sample case. Finally, the effect of Power to Gas (P2G) on the daily economic dispatch is also investigated....

  4. An Effective Conversation-Based Botnet Detection Method

    Directory of Open Access Journals (Sweden)

    Ruidong Chen

    2017-01-01

    Full Text Available A botnet is one of the most grievous threats to network security since it can evolve into many attacks, such as Denial-of-Service (DoS, spam, and phishing. However, current detection methods are inefficient to identify unknown botnet. The high-speed network environment makes botnet detection more difficult. To solve these problems, we improve the progress of packet processing technologies such as New Application Programming Interface (NAPI and zero copy and propose an efficient quasi-real-time intrusion detection system. Our work detects botnet using supervised machine learning approach under the high-speed network environment. Our contributions are summarized as follows: (1 Build a detection framework using PF_RING for sniffing and processing network traces to extract flow features dynamically. (2 Use random forest model to extract promising conversation features. (3 Analyze the performance of different classification algorithms. The proposed method is demonstrated by well-known CTU13 dataset and nonmalicious applications. The experimental results show our conversation-based detection approach can identify botnet with higher accuracy and lower false positive rate than flow-based approach.

  5. Direct catalytic conversion of methane and light hydrocarbon gases. Quarterly report No. 5, November 16, 1987--January 15, 1988

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, R.B. Jr.; Chan Yee Wai

    1988-02-05

    The goal of this research is to develop catalysts that directly convert methane and light hydrocarbons to intermediates that later can be converted to either liquid fuels or value-added chemicals, as economics dictate. During this reporting period, we have synthesized and tested several novel catalysts for methane reforming (Tasks 1 and 2) and for partial oxidation of methane (Tasks 3 and 4). We started to test a mixed metal system, an FeRu{sub 3} cluster. This catalyst was supported both on zeolite and on magnesium oxide and the systems were tested for methane reforming at various reaction temperatures. We also prepared and tested a monomeric ruthenium catalyst supported on magnesium oxide. We found that methane is activated at a lower temperature with the basic magnesium oxide support than with acidic supports such as zeolite or alumina. Methane conversions increased with temperature, but the production of coke also increased. We prepared a sterically hindered ruthenium porphyrin encapsulated in a zeolite supercage for catalysis of methane oxidation. The results showed that only carbon dioxide was produced. Addition of axial base to this catalyst gave similar results. Another type of catalyst, cobalt Schiff base complexes, was also prepared and tested for methane oxidation. In this case, no methane conversion was observed at temperatures ranging from 200 to 450{degrees}C. These complexes do not appear to be stable under the reaction conditions.

  6. A green approach to ethyl acetate: Quantitative conversion of ethanol through direct dehydrogenation in a Pd-Ag membrane reactor

    KAUST Repository

    Zeng, Gaofeng

    2012-11-07

    Pincers do the trick: The conversion of ethanol to ethyl acetate and hydrogen was achieved using a pincer-Ru catalyst in a Pd-Ag membrane reactor. Near quantitative conversions and yields could be achieved without the need for acid or base promoters or hydrogen acceptors (see scheme). © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. One-dimension-based spatially ordered architectures for solar energy conversion.

    Science.gov (United States)

    Liu, Siqi; Tang, Zi-Rong; Sun, Yugang; Colmenares, Juan Carlos; Xu, Yi-Jun

    2015-08-07

    The severe consequences of fossil fuel consumption have resulted in a need for alternative sustainable sources of energy. Conversion and storage of solar energy via a renewable method, such as photocatalysis, holds great promise as such an alternative. One-dimensional (1D) nanostructures have gained attention in solar energy conversion because they have a long axis to absorb incident sunlight yet a short radial distance for separation of photogenerated charge carriers. In particular, well-ordered spatially high dimensional architectures based on 1D nanostructures with well-defined facets or anisotropic shapes offer an exciting opportunity for bridging the gap between 1D nanostructures and the micro and macro world, providing a platform for integration of nanostructures on a larger and more manageable scale into high-performance solar energy conversion applications. In this review, we focus on the progress of photocatalytic solar energy conversion over controlled one-dimension-based spatially ordered architecture hybrids. Assembly and classification of these novel architectures are summarized, and we discuss the opportunity and future direction of integration of 1D materials into high-dimensional, spatially organized architectures, with a perspective toward improved collective performance in various artificial photoredox applications.

  8. Direct conversion of lignocellulose to levulinic acid catalyzed by ionic liquid.

    Science.gov (United States)

    Liu, Li; Li, Zhenrui; Hou, Wuxin; Shen, Haiyan

    2018-02-01

    Acidic ionic liquid (IL) [C 3 SO 3 Hmim]HSO 4 was applied to catalyze lignocellulose conversion to levulinic acid (LA) in one pot with high selectivity under hydrothermal conditions. Through the optimization of reaction conditions, the highest yield of LA is 96.6mol% (21.6wt%) based on the amount of C6-sugars in the straw. The relationship between IL structure and LA yield was established, disclosing that acidity and hydrogen bonding ability of anions are crucial to the yield of LA. Moreover, the LA product can be readily separated through extraction by methyl isobutyl ketone (MIBK) and IL can be reused over 5 cycles without loss of activity. In addition, the chemical structures and morphologies of the solid residues were investigated by DTG, SEM and IR, demonstrating the gradual conversion process of cellulose and hemicellulose accompanied by the formation of humin byproducts, whereas the lignin fraction of the straw sustains the scaffold structure without modifications during the reaction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Use of nuclear space technology of direct energy conversion for terrestrial application

    International Nuclear Information System (INIS)

    Chitaykin, V.I.; Meleta, Ye.A.; Yarygin, V.I.; Mikheyev, A.S.; Tulin, S.M.

    2000-01-01

    In due time the SSC RF-IPPE exercised the scientific supervision and directly participated in the development, fabrication, space flight test and maintenance of the direct energy conversion nuclear power plants (NPP) for space application under the 'BUK' and 'TOPAZ' programs. We have used the acquired experience and the high technologies developed for the 'BUK' NPP with a thermoelectric conversion of thermal (nuclear) energy into electrical one in the development under the order of RAO 'GAZPROM' of the natural gas fired self contained thermoelectric current sources (AIT-500) and heat and electricity sources (TEP-500). These are intended for electrochemical rust protection of gas pipelines and for the electricity and heat supply to the telemetric and microwave-link systems located along the gas pipelines. Of special interest at the moment are the new developments of self contained current sources with the electrical output of ∼500 Wel for new gas pipelines being constructed under the projects such as the 'Yamal-Europe' project. The electrochemical rust protection of gas pipelines laying on unsettled and non-electrified territory of arctic regions of Russia is performed by means of the so-called Cathodic Protection Stations (CPS). Accounting for a complex of rather rigid requirements imposed by arctic operating conditions, the most attractive sources of electricity supply to the CPS are the thermoelectric heat-into-electricity converters and the generators (TEG). This paper deals with the essential results of the development, investigation and testing of unconventional TEGs using the low-temperature bismuth-tellurium thermoelectric batteries assembled together as tubular thermoelectric batteries with a radial ring geometry built into the gas-heated thermoelectric modules, which are collected to make up either the thermoelectric plants for heat and electricity supply or the self contained power sources. One of the peculiarities of these plants is the combination of

  10. Versatile nickel–tungsten bimetallics/carbon nanofiber catalysts for direct conversion of cellulose to ethylene glycol

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ying; Zhang, Wen; Yang, Feng; Brown, Dennis E.; Ren, Yang; Lee, Sungsik; Zeng, Dehong; Gao, Qiang; Zhang, Xin

    2016-01-01

    We herein propose a novel synthetic methodology for a series of nickel–tungsten bimetallics/carbon nanofiber catalysts (Ni, 0.37–2.08 wt%; W, 0.01–0.06 wt%) in situ fabricated by pyrolysis (950 °C) of Ni, W and Zn-containing metal organic framework (Ni0.6-x–Wx–ZnBTC, x = 0–0.6) fibers. The resulting catalysts (Ni0.6-x–Wx/CNF) have uniform particles (ca. 68 nm), evenly dispersed onto the hierarchically porous carbon nanofibers formed simultaneously. All of the Ni0.6-x–Wx/CNF catalysts prove to be highly active towards direct conversion of cellulose to ethylene glycol (EG). A large productivity ranging from 15.3 to 70.8 molEG h-1 gW-1 is shown, two orders of magnitude higher than those by using other W-based catalysts reported.

  11. A GIS-based Model for Natural Gas Data Conversion

    Science.gov (United States)

    Bitik, E.; Seker, D. Z.; Denli, H. H.

    2014-12-01

    In Turkey gas utility sector has undergone major changes in terms of increased competition between gas providers, efforts in improving services, and applying new technological solutions. This paper discusses the challenges met by gas companies to switch from long workflows of gas distribution, sales and maintenance into IT driven efficient management of complex information both spatially and non-spatially. The aim of this study is migration of all gas data and information into a GIS environment in order to manage and operate all infrastructure investments with a Utility Management System. All data conversion model for migration was designed and tested during the study. A flowchart is formed to transfer the old data layers to the new structure based on geodatabase.

  12. Complex Nanostructures from Materials based on Metal-Organic Frameworks for Electrochemical Energy Storage and Conversion.

    Science.gov (United States)

    Guan, Bu Yuan; Yu, Xin Yao; Wu, Hao Bin; Lou, Xiong Wen David

    2017-12-01

    Metal-organic frameworks (MOFs) have drawn tremendous attention because of their abundant diversity in structure and composition. Recently, there has been growing research interest in deriving advanced nanomaterials with complex architectures and tailored chemical compositions from MOF-based precursors for electrochemical energy storage and conversion. Here, a comprehensive overview of the synthesis and energy-related applications of complex nanostructures derived from MOF-based precursors is provided. After a brief summary of synthetic methods of MOF-based templates and their conversion to desirable nanostructures, delicate designs and preparation of complex architectures from MOFs or their composites are described in detail, including porous structures, single-shelled hollow structures, and multishelled hollow structures, as well as other unusual complex structures. Afterward, their applications are discussed as electrode materials or catalysts for lithium-ion batteries, hybrid supercapacitors, water-splitting devices, and fuel cells. Lastly, the research challenges and possible development directions of complex nanostructures derived from MOF-based-templates for electrochemical energy storage and conversion applications are outlined. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Simulation and Experimental Study on the Efficiency of Traveling Wave Direct Energy Conversion for Application to Aneutronic Fusion Reactions

    Science.gov (United States)

    Tarditi, Alfonso; Chap, Andrew; Miley, George; Scott, John

    2013-10-01

    A study based on both Particle-in-cell (PIC) simulation and experiments is being developed to study the physics of the Traveling Wave Direct Energy Converter (TWDEC,) with the perspective of application to aneutronic fusion reaction products and space propulsion. The PIC model is investigating in detail the key TWDEC physics process by simulating the time-dependent transfer of energy from the ion beam to an electric load connected to ring-type electrodes in cylindrical symmetry. An experimental effort is in progress on a TWDEC test article at NASA, Johnson Space Center with the purpose of studying the conditions for improving the efficiency of the direct energy conversion process. Using a scaled-down ion energy source, the experiment is primarily focused on the effect of the (bunched) beam density on the efficiency and on the optimization of the electrode design. The simulation model is guiding the development of the experimental configuration and will provide details of the beam dynamics for direct comparison with experimental diagnostics. Work supported by NASA, Johnson Space Center.

  14. Conversion of solar energy into electricity by using duckweed in Direct Photosynthetic Plant Fuel Cell.

    Science.gov (United States)

    Hubenova, Yolina; Mitov, Mario

    2012-10-01

    In the present study we demonstrate for the first time the possibility for conversion of solar energy into electricity on the principles of Direct Photosynthetic Plant Fuel Cell (DPPFC) technology by using aquatic higher plants. Lemna minuta duckweed was grown autotrophically in specially constructed fuel cells under sunlight irradiation and laboratory lighting. Current and power density up to 1.62±0.10 A.m(-2) and 380±19 mW.m(-2), respectively, were achieved under sunlight conditions. The influence of the temperature, light intensity and day/night sequencing on the current generation was investigated. The importance of the light intensity was demonstrated by the higher values of generated current (at permanently connected resistance) during daytime than those through the nights, indicating the participation of light-dependent photosynthetic processes. The obtained DPPFC outputs in the night show the contribution of light-independent reactions (respiration). The electron transfer in the examined DPPFCs is associated with a production of endogenous mediator, secreted by the duckweed. The plants' adaptive response to the applied polarization is also connected with an enhanced metabolism resulting in an increase of the protein and carbohydrate intracellular content. Further investigations aiming at improvement of the DPPFC outputs and elucidation of the electron transfer mechanism are required for practical application. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Direct Conversion of CO2to α-Farnesene Using Metabolically Engineered Synechococcus elongatus PCC 7942.

    Science.gov (United States)

    Lee, Hyun Jeong; Lee, Jiwon; Lee, Sun-Mi; Um, Youngsoon; Kim, Yunje; Sim, Sang Jun; Choi, Jong-Il; Woo, Han Min

    2017-12-06

    Direct conversion of carbon dioxide (CO 2 ) to value-added chemicals by engineering of cyanobacteria has received attention as a sustainable strategy in food and chemical industries. Herein, Synechococcus elongatus PCC 7942, a model cyanobacterium, was engineered to produce α-farnesene from CO 2 . As a result of the lack of farnesene synthase (FS) activity in the wild-type cyanobacterium, we metabolically engineered S. elongatus PCC 7942 to express heterologous FS from either Norway spruce or apple fruit, resulting in detectable peaks of α-farnesene. To enhance α-farnesene production, an optimized methylerythritol phosphate (MEP) pathway was introduced in the farnesene-producing strain to supply farnesyl diphosphate. Subsequent cyanobacterial culture with a dodecane overlay resulted in photosynthetic production of α-farnesene (4.6 ± 0.4 mg/L in 7 days) from CO 2 . To the best of our knowledge, this is the first report of the photosynthetic production of α-farnesene from CO 2 in the unicellular cyanobacterium S. elongatus PCC 7942.

  16. Nonviral Direct Conversion of Primary Mouse Embryonic Fibroblasts to Neuronal Cells

    Directory of Open Access Journals (Sweden)

    Andrew F Adler

    2012-01-01

    Full Text Available Transdifferentiation, where differentiated cells are reprogrammed into another lineage without going through an intermediate proliferative stem cell-like stage, is the next frontier of regenerative medicine. Wernig et al. first described the direct conversion of fibroblasts into functional induced neuronal cells (iNs. Subsequent reports of transdifferentiation into clinically relevant neuronal subtypes have further endorsed the prospect of autologous cell therapy for neurodegenerative disorders. So far, all published neuronal transdifferentiation protocols rely on lentiviruses, which likely precludes their clinical translation. Instead, we delivered plasmids encoding neuronal transcription factors (Brn2, Ascl1, Myt1l to primary mouse embryonic fibroblasts with a bioreducible linear poly(amido amine. The low toxicity and high transfection efficiency of this gene carrier allowed repeated dosing to sustain high transgene expression levels. Serial 0.5 µg cm−2 doses of reprogramming factors delivered at 48-hour intervals produced up to 7.6% Tuj1+ (neuron-specific class III β-tubulin cells, a subset of which expressed MAP2 (microtubule-associated protein 2, tau, and synaptophysin. A synapsin-red fluorescent protein (RFP reporter helped to identify more mature, electrophysiologically active cells, with 24/26 patch-clamped RFP+ cells firing action potentials. Some non-virally induced neuronal cells (NiNs were observed firing multiple and spontaneous action potentials. This study demonstrates the feasibility of nonviral neuronal transdifferentiation, and may be amenable to other transdifferentiation processes.

  17. Direct xylan conversion into glycolipid biosurfactants, mannosylerythritol lipids, by Pseudozyma antarctica PYCC 5048(T).

    Science.gov (United States)

    Faria, Nuno Torres; Marques, Susana; Fonseca, César; Ferreira, Frederico Castelo

    2015-04-01

    Mannosylerythritol lipids (MEL) are glycolipid biosurfactants, produced by Pseudozyma spp., with increasing commercial interest. While MEL can be produced from d-glucose and d-xylose, the direct conversion of the respective lignocellulosic polysaccharides, cellulose and xylan, was not reported yet. The ability of Pseudozyma antarctica PYCC 5048(T) and Pseudozyma aphidis PYCC 5535(T) to use cellulose (Avicel(®)) and xylan (beechwood) as carbon and energy source has been assessed along with their capacity of producing cellulolytic and hemicellulolytic enzymes, toward a consolidated bioprocess (CBP) for MEL production. The yeasts assessed were neither able to grow in medium containing Avicel(®) nor produce cellulolytic enzymes under the conditions tested. On contrary, both yeasts were able to efficiently grow in xylan, but MEL production was only detected in P. antarctica PYCC 5048(T) cultures. MEL titers reached 1.3g/l after 10 days in batch cultures with 40g/l xylan, and 2.0g/l in fed-batch cultures with xylan feeding (additional 40g/l) at day 4. High levels of xylanase activities were detected in xylan cultures, reaching 47-62U/ml (31-32U/mg) at 50°C, and still exhibiting more than 10U/ml under physiological temperature (28°C). Total β-xylosidase activities, displayed mainly as wall-bounded and extracellular activity, accounted for 0.154 and 0.176U/ml in P. antarctica PYCC 5048(T) and P. aphidis PYCC 5535(T) cultures, respectively. The present results demonstrate the potential of Pseudozyma spp. for using directly a fraction of lignocellulosic biomass, xylan, and combining in the same bioprocess the production of xylanolytic enzymes with MEL production. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Computer-Assisted English Learning System Based on Free Conversation by Topic

    Science.gov (United States)

    Choi, Sung-Kwon; Kwon, Oh-Woog; Kim, Young-Kil

    2017-01-01

    This paper aims to describe a computer-assisted English learning system using chatbots and dialogue systems, which allow free conversation outside the topic without limiting the learner's flow of conversation. The evaluation was conducted by 20 experimenters. The performance of the system based on a free conversation by topic was measured by the…

  19. Apparatus for the direct conversion of the kinetic energy of charged particles

    International Nuclear Information System (INIS)

    Mims, L.S.

    1976-01-01

    An apparatus for converting the output of a high voltage dc source to a lower voltage and a higher current is described. The conversion system is comprised of a plurality of power conversion modules connected electrically in series across the dc source output so that each of the power conversion modules receives only a portion of the high voltage. Each power conversion module includes means for converting the high voltage portion to an ac signal and transformer means for reducing the voltage and increasing the current of such ac signal, the outputs of all of the transformers being connected electrically in parallel. Each of the power conversion means includes a pair of capacitors which are charged by the high voltage dc source and which are alternately, periodically only slightly discharged to convert the dc voltage to an ac signal

  20. Direct observation and modelling of ordered hydrogen adsorption and catalyzed ortho-para conversion on ETS-10 titanosilicate material.

    Science.gov (United States)

    Ricchiardi, Gabriele; Vitillo, Jenny G; Cocina, Donato; Gribov, Evgueni N; Zecchina, Adriano

    2007-06-07

    Hydrogen physisorption on porous high surface materials is investigated for the purpose of hydrogen storage and hydrogen separation, because of its simplicity and intrinsic reversibility. For these purposes, the understanding of the binding of dihydrogen to materials, of the structure of the adsorbed phase and of the ortho-para conversion during thermal and pressure cycles are crucial for the development of new hydrogen adsorbents. We report the direct observation by IR spectroscopic methods of structured hydrogen adsorption on a porous titanosilicate (ETS-10), with resolution of the kinetics of the ortho-para transition, and an interpretation of the structure of the adsorbed phase based on classical atomistic simulations. Distinct infrared signals of o- and p-H2 in different adsorbed states are measured, and the conversion of o- to p-H2 is monitored over a timescale of hours, indicating the presence of a catalyzed reaction. Hydrogen adsorption occurs in three different regimes characterized by well separated IR manifestations: at low pressures ordered 1:1 adducts with Na and K ions exposed in the channels of the material are formed, which gradually convert into ordered 2:1 adducts. Further addition of H2 occurs only through the formation of a disordered condensed phase. The binding enthalpy of the Na+-H2 1:1 adduct is of -8.7+/-0.1 kJ mol(-1), as measured spectroscopically. Modeling of the weak interaction of H2 with the materials requires an accurate force field with a precise description of both dispersion and electrostatics. A novel three body force field for molecular hydrogen is presented, based on the fitting of an accurate PES for the H2-H2 interaction to the experimental dipole polarizability and quadrupole moment. Molecular mechanics simulations of hydrogen adsorption at different coverages confirm the three regimes of adsorption and the structure of the adsorbed phase.

  1. ForConX: A forcefield conversion tool based on XML.

    Science.gov (United States)

    Lesch, Volker; Diddens, Diddo; Bernardes, Carlos E S; Golub, Benjamin; Dequidt, Alain; Zeindlhofer, Veronika; Sega, Marcello; Schröder, Christian

    2017-04-05

    The force field conversion from one MD program to another one is exhausting and error-prone. Although single conversion tools from one MD program to another exist not every combination and both directions of conversion are available for the favorite MD programs Amber, Charmm, Dl-Poly, Gromacs, and Lammps. We present here a general tool for the force field conversion on the basis of an XML document. The force field is converted to and from this XML structure facilitating the implementation of new MD programs for the conversion. Furthermore, the XML structure is human readable and can be manipulated before continuing the conversion. We report, as testcases, the conversions of topologies for acetonitrile, dimethylformamide, and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate comprising also Urey-Bradley and Ryckaert-Bellemans potentials. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  2. Quality Enhancement of Compressed Audio Based on Statistical Conversion

    Directory of Open Access Journals (Sweden)

    Mouchtaris Athanasios

    2008-01-01

    Full Text Available Most audio compression formats are based on the idea of low bit rate transparent encoding. As these types of audio signals are starting to migrate from portable players with inexpensive headphones to higher quality home audio systems, it is becoming evident that higher bit rates may be required to maintain transparency. We propose a novel method that enhances low bit rate encoded audio segments by applying multiband audio resynthesis methods in a postprocessing stage. Our algorithm employs the highly flexible Generalized Gaussian mixture model which offers a more accurate representation of audio features than the Gaussian mixture model. A novel residual conversion technique is applied which proves to significantly improve the enhancement performance without excessive overhead. In addition, both cepstral and residual errors are dramatically decreased by a feature-alignment scheme that employs a sorting transformation. Some improvements regarding the quantization step are also described that enable us to further reduce the algorithm overhead. Signal enhancement examples are presented and the results show that the overhead size incurred by the algorithm is a fraction of the uncompressed signal size. Our results show that the resulting audio quality is comparable to that of a standard perceptual codec operating at approximately the same bit rate.

  3. Quality Enhancement of Compressed Audio Based on Statistical Conversion

    Directory of Open Access Journals (Sweden)

    Chris Kyriakakis

    2008-07-01

    Full Text Available Most audio compression formats are based on the idea of low bit rate transparent encoding. As these types of audio signals are starting to migrate from portable players with inexpensive headphones to higher quality home audio systems, it is becoming evident that higher bit rates may be required to maintain transparency. We propose a novel method that enhances low bit rate encoded audio segments by applying multiband audio resynthesis methods in a postprocessing stage. Our algorithm employs the highly flexible Generalized Gaussian mixture model which offers a more accurate representation of audio features than the Gaussian mixture model. A novel residual conversion technique is applied which proves to significantly improve the enhancement performance without excessive overhead. In addition, both cepstral and residual errors are dramatically decreased by a feature-alignment scheme that employs a sorting transformation. Some improvements regarding the quantization step are also described that enable us to further reduce the algorithm overhead. Signal enhancement examples are presented and the results show that the overhead size incurred by the algorithm is a fraction of the uncompressed signal size. Our results show that the resulting audio quality is comparable to that of a standard perceptual codec operating at approximately the same bit rate.

  4. Space-based solar power conversion and delivery systems study

    Science.gov (United States)

    1976-01-01

    Even at reduced rates of growth, the demand for electric power is expected to more than triple between now and 1995, and to triple again over the period 1995-2020. Without the development of new power sources and advanced transmission technologies, it may not be possible to supply electric energy at prices that are conductive to generalized economic welfare. Solar power is renewable and its conversion and transmission from space may be advantageous. The goal of this study is to assess the economic merit of space-based photovoltaic systems for power generation and a power relay satellite for power transmission. In this study, satellite solar power generation and transmission systems, as represented by current configurations of the Satellite Solar Station (SSPS) and the Power Relay Satellite (PRS), are compared with current and future terrestrial power generation and transmission systems to determine their technical and economic suitability for meeting power demands in the period of 1990 and beyond while meeting ever-increasing environmental and social constraints.

  5. Energy conversion performance of black liquor gasification to hydrogen production using direct causticization with CO(2) capture.

    Science.gov (United States)

    Naqvi, M; Yan, J; Dahlquist, E

    2012-04-01

    This paper estimates potential hydrogen production via dry black liquor gasification system with direct causticization integrated with a reference pulp mill. The advantage of using direct causticization is elimination of energy intensive lime kiln. Pressure swing adsorption is integrated in the carbon capture process for hydrogen upgrading. The energy conversion performance of the integrated system is compared with other bio-fuel alternatives and evaluated based on system performance indicators. The results indicated a significant hydrogen production potential (about 141MW) with an energy ratio of about 0.74 from the reference black liquor capacity (about 243.5MW) and extra biomass import (about 50MW) to compensate total energy deficit. About 867,000tonnes of CO(2) abatement per year is estimated i.e. combining CO(2) capture and CO(2) offset from hydrogen replacing motor gasoline. The hydrogen production offers a substantial motor fuel replacement especially in regions with large pulp and paper industry e.g. about 63% of domestic gasoline replacement in Sweden. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Energy Conversion Efficiency Potential for Forward-Deployed Generation Using Direct Carbon Fuel Cells

    Science.gov (United States)

    2012-05-01

    ficiency of any other conversion technology and twice that of standard coal-fired power plants . For the same electrical output, a power generation system...efficiency — well beyond the efficiency of any other conversion tech- nology and twice that of standard coal-fired power plants . The challenge with the DCFC...carbon is being de- rived from waste or from pyrolysis of a liquid fuel. The carbon powder produced by pyrolysis of waste or fuel would have to be

  7. Performance Comparison of Steam-Based and Chromate Conversion Coatings on Aluminum Alloy 6060

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-01-01

    In this study, oxide layers generated on aluminum alloy 6060(UNS A96060) using a steam-based process were compared with conventional chromate and chromate-phosphate conversion coatings. Chemical composition and microstructure of the conversion coatings were investigated and their corrosion...... performance was evaluated using potentio dynamic polarization, acetic acid salt spray, and filiform corrosion testing of powder coated specimens. The steam-based process resulted in homogenous growth of oxide layer and superior coverageover intermetallic particles when compared to chromate-based conversion...... coatings. The coating formed by steam showed improved corrosion resistance, while adhesion to powder coatingand filiform corrosion was comparable with chromate conversion coatings....

  8. Enculturating Conversational Agents based on a Comparative Corpus Study

    DEFF Research Database (Denmark)

    Lipi, Afia Akhter; Yamaoka, Yuji; Rehm, Matthias

    2008-01-01

    When encountering people who have a different cultural background from our own, many of us feel uncomfortable because gestures and facial expressions may not be familiar to us. Thus, to enhance the believability of conversational agents, culture-specific nonverbal behaviors should be implemented ...... a more detailed analysis about posture shifts, and proposes a chat system with an embodied conversational agent (ECA) that can act as a language trainer....... into the agents. In our previous study, with the goal of building a user interface that incorporates a user’s cultural background, we have collected comparative conversation corpus in Germany and Japan, and investigated the differences in gestures and posture shifts between these two countries. This paper reports...

  9. Directed plant cell-wall accumulation of iron: embedding co-catalyst for efficient biomass conversion.

    Science.gov (United States)

    Lin, Chien-Yuan; Jakes, Joseph E; Donohoe, Bryon S; Ciesielski, Peter N; Yang, Haibing; Gleber, Sophie-Charlotte; Vogt, Stefan; Ding, Shi-You; Peer, Wendy A; Murphy, Angus S; McCann, Maureen C; Himmel, Michael E; Tucker, Melvin P; Wei, Hui

    2016-01-01

    Plant lignocellulosic biomass is an abundant, renewable feedstock for the production of biobased fuels and chemicals. Previously, we showed that iron can act as a co-catalyst to improve the deconstruction of lignocellulosic biomass. However, directly adding iron catalysts into biomass prior to pretreatment is diffusion limited, and increases the cost of biorefinery operations. Recently, we developed a new strategy for expressing iron-storage protein ferritin intracellularly to accumulate iron as a catalyst for the downstream deconstruction of lignocellulosic biomass. In this study, we extend this approach by fusing the heterologous ferritin gene with a signal peptide for secretion into Arabidopsis cell walls (referred to here as FerEX). The transgenic Arabidopsis plants. FerEX. accumulated iron under both normal and iron-fertilized growth conditions; under the latter (iron-fertilized) condition, FerEX transgenic plants showed an increase in plant height and dry weight by 12 and 18 %, respectively, compared with the empty vector control plants. The SDS- and native-PAGE separation of cell-wall protein extracts followed by Western blot analyses confirmed the extracellular expression of ferritin in FerEX plants. Meanwhile, Perls' Prussian blue staining and X-ray fluorescence microscopy (XFM) maps revealed iron depositions in both the secondary and compound middle lamellae cell-wall layers, as well as in some of the corner compound middle lamella in FerEX. Remarkably, their harvested biomasses showed enhanced pretreatability and digestibility, releasing, respectively, 21 % more glucose and 34 % more xylose than the empty vector control plants. These values are significantly higher than those of our recently obtained ferritin intracellularly expressed plants. This study demonstrated that extracellular expression of ferritin in Arabidopsis can produce plants with increased growth and iron accumulation, and reduced thermal and enzymatic recalcitrance. The results are

  10. Transparent organic light-emitting diodes with different bi-directional emission colors using color-conversion capping layers

    International Nuclear Information System (INIS)

    Lee, Jonghee; Koh, Tae-Wook; Cho, Hyunsu; Schwab, Tobias; Lee, Jae-Hyun; Hofmann, Simone; Lee, Jeong-Ik; Yoo, Seunghyup

    2015-01-01

    We report a study on transparent organic light-emitting diodes (OLEDs) with different bi-directional emission colors, enabled by color-conversion organic capping layers. Starting from a transparent blue OLED with an uncapped Ag top electrode exhibiting an average transmittance of 33.9%, a 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM)-doped tris-(8-hydroxy-quinolinato)-aluminum (Alq3) capping layer is applied to achieve color-conversion from blue to orange-red on the top side while maintaining almost unchanged device transmittance. This color-conversion capping layer does not only change the color of the top side emission, but also enhances the overall device efficiency due to the optical interaction of the capping layer with the primary blue transparent OLED. Top white emission from the transparent bi-directional OLED exhibits a correlated color temperature around 6000–7000 K, with excellent color stability as evidenced by an extremely small variation in color coordinate of Δ(x,y)=(0.002, 0.002) in the forward luminance range of 100–1000 cd m −2 . At the same time, the blue emission color of bottom side is not influenced by the color conversion capping layer, which finally results in different emission colors of the two opposite sides of our transparent OLEDs. - Highlights: • We report transparent organic light-emitting diodes (OLEDs) with different bi-directional emission colors. • Transparent blue OLED with color-conversion organic capping layers (CCL) shows orange top side emission. • Top white emission exhibits a CCT around 7000 K, with excellent color stability on a driving voltage

  11. A novel energy conversion based method for velocity correction in molecular dynamics simulations

    International Nuclear Information System (INIS)

    Jin, Hanhui; Liu, Ningning; Ku, Xiaoke; Fan, Jianren

    2017-01-01

    Molecular dynamics (MD) simulation has become an important tool for studying micro- or nano-scale dynamics and the statistical properties of fluids and solids. In MD simulations, there are mainly two approaches: equilibrium and non-equilibrium molecular dynamics (EMD and NEMD). In this paper, a new energy conversion based correction (ECBC) method for MD is developed. Unlike the traditional systematic correction based on macroscopic parameters, the ECBC method is developed strictly based on the physical interaction processes between the pair of molecules or atoms. The developed ECBC method can apply to EMD and NEMD directly. While using MD with this method, the difference between the EMD and NEMD is eliminated, and no macroscopic parameters such as external imposed potentials or coefficients are needed. With this method, many limits of using MD are lifted. The application scope of MD is greatly extended.

  12. Direct-Conversion Molecular Breast Imaging of Invasive Breast Cancer: Imaging Features, Extent of Invasive Disease, and Comparison Between Invasive Ductal and Lobular Histology.

    Science.gov (United States)

    Conners, Amy Lynn; Jones, Katie N; Hruska, Carrie B; Geske, Jennifer R; Boughey, Judy C; Rhodes, Deborah J

    2015-09-01

    The purposes of this study were to compare the tumor appearance of invasive breast cancer on direct-conversion molecular breast imaging using a standardized lexicon and to determine how often direct-conversion molecular breast imaging identifies all known invasive tumor foci in the breast, and whether this differs for invasive ductal versus lobular histologic profiles. Patients with prior invasive breast cancer and concurrent direct-conversion molecular breast imaging examinations were retrospectively reviewed. Blinded review of direct-conversion molecular breast imaging examinations was performed by one of two radiologists, according to a validated lexicon. Direct-conversion molecular breast imaging findings were matched with lesions described on the pathology report to exclude benign reasons for direct-conversion molecular breast imaging findings and to document direct-conversion molecular breast imaging-occult tumor foci. Associations between direct-conversion molecular breast imaging findings and tumor histologic profiles were examined using chi-square tests. In 286 patients, 390 invasive tumor foci were present in 294 breasts. A corresponding direct-conversion molecular breast imaging finding was present for 341 of 390 (87%) tumor foci described on the pathology report. Invasive ductal carcinoma (IDC) tumor foci were more likely to be a mass (40% IDC vs 15% invasive lobular carcinoma [ILC]; p invasive disease in 79.8% of cases and was more likely to do so for IDC than for ILC (86.1% vs 56.7%; p invasive foci in 249 of 286 (87%) patients. Direct-conversion molecular breast imaging features of invasive cancer, including lesion type and intensity, differ by histologic subtype. Direct-conversion molecular breast imaging is less likely to show all foci of ILC compared with IDC.

  13. Determination of conversion factors due to the direct and backscattered emission of terrestrial photons gamma

    International Nuclear Information System (INIS)

    Askri, Boubaker

    2008-01-01

    In this thesis we are based on physical criteria to develop a model describing the ground by an optimized geometry in the Monte Carlo simulation of the emission of gamma radiation on earth. This geometry has a unique parameter soil depth. This geometry has been tested successfully. It produced more than 98 pour cent of absorbed dose rate in air at one meter from the ground level and 100 pour cent of the flow line for a uniform distribution of the source and more than 99 pour cent of absorbed dose rate for an exponential distribution source. A considerable gain in computing time compared to classical models was achieved. The backscattered component is more important for low energies than for high-energy emission. By applying the optimized model of soil-air, it reached 100 pour cent of absorbed dose rate in air at a reduced computational time. The conversion factors of dose rate for both filiations natural uranium and thorium were determined by simulation with the optimized geometry. A good agreement was achieved with the values published in the literature. To test this model experimentally, it was necessary to transform the spectrum acquired by a portable germanium detector in a distribution of energy flux of photons to calculate the dose rate experiment. That's why we propose a method for calibration of portable germanium detector by Monte Carlo simulation. In this method, we used a model of diffusion of lithium in germanium to find the thickness of the dead layer of germanium crystal, a parameter not available with precision by the detector. On the basis of the conversion factors calculated using the optimized geometry and the data sampling conducted in the soil of the National Center for Nuclear Science and Technology in Tunis, the value of dose rate was calculated. This value is close to the experimental value of dose rate, which presents the first experimental validation. The optimization made to geometry was used to simulate an aspect related to the spread of

  14. High-performance liquid-catalyst fuel cell for direct biomass-into-electricity conversion.

    Science.gov (United States)

    Liu, Wei; Mu, Wei; Deng, Yulin

    2014-12-01

    Herein, we report high-performance fuel cells that are catalyzed solely by polyoxometalate (POM) solution without any solid metal or metal oxide. The novel design of the liquid-catalyst fuel cells (LCFC) changes the traditional gas-solid-surface heterogeneous reactions to liquid-catalysis reactions. With this design, raw biomasses, such as cellulose, starch, and even grass or wood powders can be directly converted into electricity. The power densities of the fuel cell with switchgrass (dry powder) and bush allamanda (freshly collected) are 44 mW cm(-2) and 51 mW cm(-2) respectively. For the cellulose-based biomass fuel cell, the power density is almost 3000 times higher than that of cellulose-based microbial fuel cells. Unlike noble-metal catalysts, POMs are tolerant to most organic and inorganic contaminants. Therefore, almost any raw biomass can be used directly to produce electricity without prior purification. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Enculturating Conversational Agents based on a Comparative Corpus Study

    DEFF Research Database (Denmark)

    Lipi, Afia Akhter; Yamaoka, Yuji; Rehm, Matthias

    2008-01-01

    When encountering people who have a different cultural background from our own, many of us feel uncomfortable because gestures and facial expressions may not be familiar to us. Thus, to enhance the believability of conversational agents, culture-specific nonverbal behaviors should be implemented...

  16. Clinical evaluation of digital angiographic system equipped with the Safire' flat-panel detector of a direct conversion type

    International Nuclear Information System (INIS)

    Miura, Yoshiaki; Miura, Yusuke; Goto, Keiichi

    2003-01-01

    This report presents a report on clinical evaluation of our newly developed flat-panel X-ray detector of a direct conversion type, designed to provide images of a resolution higher than, or at least equal to, that ensured by X-ray photographic films, in clinical digital X-ray cinematography. This new detector was named 'Safire' the acronym of 'Shimadzu advanced flat imaging receptor', emphasizing its high technological level, such as the capability to ensure high quality of images. The clinical evaluation of Shimadzu DIGITEX Premier digital angiography system, equipped with this new flat-panel X-ray detector of a direct conversion type, has been started in March, 2003, at the Kokura Memorial Hospital in Kyushu, Japan. (author)

  17. Steady-state analysis of the integrated natural gas and electric power system with bi-directional energy conversion

    DEFF Research Database (Denmark)

    Zeng, Qing; Fang, Jiakun; Li, Jinghua

    2016-01-01

    Nowadays, the electric power system and natural gas network are becoming increasingly coupled and interdependent. A harmonized integration of natural gas and electricity network with bi-directional energy conversion is expected to accommodate high penetration levels of renewables in terms of system...... flexibility. This work focuses on the steady-state analysis of the integrated natural gas and electric power system with bi-directional energy conversion. A unified energy flow formulation is developed to describe the nodal balance and branch flow in both systems and it is solved with the Newton......–Raphson method. Both the unification of units and the per-unit system are proposed to simplify the system description and to enhance the computation efficiency. The applicability of the proposed method is demonstrated by analyzing an IEEE-9 test system integrated with a 7-node natural gas network. Later, time...

  18. Synthesis and processing of materials for direct thermal-to-electric energy conversion and storage

    Science.gov (United States)

    Thompson, Travis

    Currently, fossil fuels are the primary source of energy. Mechanical heat engines convert the chemical potential energy in fossil fuels to useful electrical energy through combustion; a relatively low efficiency process that generates carbon dioxide. This practice has led to a significant increase in carbon dioxide emissions and is contributing to climate change. However, not all heat engines are mechanical. Alternative energy generation technologies to mechanical heat engines are known, yet underutilized. Thermoelectric generators are solid-state devices originally developed by NASA to power deep space spacecraft, which can also convert heat into electricity but without any moving parts. Similar to their mechanical counterparts, any heat source, including the burning of fossil fuels, can be used. However, clean heat sources, such as concentrated solar, can alternatively be used. Since the energy sources for many of the alternative energy technologies is intermittent, including concentrated solar for thermoelectric devices, load matching is difficult or impossible and an energy storage technology is needed in addition to the energy conversion technology. This increases the overall cost and complexity of the systems since two devices are required and represents a significant barrier for mass adoption of an alternative energy technology. However, it is possible to convert heat energy to electrical energy and store excess charge for use at a later time when the demand increases, in a single device. One such of a device is a thermogalvanic generator and is the electrochemical analog of electronic thermoelectric devices. Essentially, a thermogalvanic device represents the combination of thermoelectric and galvanic systems. As such, the rich history of strategies developed by both the thermoelectric community to better the performance of thermoelectric devices and by the electrochemical community to better traditional galvanic devices (i.e. batteries) can be applied to

  19. Half-time Tc-99m sestamibi imaging with a direct conversion molecular breast imaging system.

    Science.gov (United States)

    Hruska, Carrie B; Conners, Amy Lynn; Jones, Katie N; Weinmann, Amanda L; Lingineni, Ravi K; Carter, Rickey E; Rhodes, Deborah J; O'Connor, Michael K

    2014-01-15

    In an effort to reduce necessary acquisition time to perform molecular breast imaging (MBI), we compared diagnostic performance of MBI performed with standard 10-min-per-view acquisitions and half-time 5-min-per-view acquisitions, with and without wide beam reconstruction (WBR) processing. Eighty-two bilateral, two-view MBI studies were reviewed. Studies were performed with 300 MBq Tc-99 m sestamibi and a direct conversion molecular breast imaging (DC-MBI) system. Acquisitions were 10 min-per-view; the first half of each was extracted to create 5-min-per-view datasets, and WBR processing was applied.The 10-min-, 5-min-, and 5-min-per-view WBR studies were independently interpreted in a randomized, blinded fashion by two radiologists. Assessments of 1 to 5 were assigned; 4 and 5 were considered test positive. Background parenchymal uptake, lesion type, distribution of non-mass lesions, lesion intensity, and image quality were described. Considering detection of all malignant and benign lesions, 5 min-per-view MBI had lower sensitivity (mean of 70% vs. 85% (p ≤ 0.04) for two readers) and lower area under curve (AUC) (mean of 92.7 vs. 99.6, p ≤ 0.01) but had similar specificity (p = 1.0). WBR processing did not alter sensitivity, specificity, or AUC obtained at 5 min-per-view.Overall agreement in final assessment between 5-min-per-view and 10-min-per-view acquisition types was near perfect (κ = 0.82 to 0.89); however, fair to moderate agreement was observed for assessment category 3 (probably benign) (κ = 0.24 to 0.48). Of 33 malignant lesions, 6 (18%) were changed from assessment of 4 or 5 with 10-min-per-view MBI to assessment of 3 with 5-min-per-view MBI. Image quality of 5-min-per-view studies was reduced compared to 10-min-per-view studies for both readers (3.24 vs. 3.98, p < 0.0001 and 3.60 vs. 3.91, p < 0.0001). WBR processing improved image quality for one reader (3.85 vs. 3.24, p < 0.0001). Although similar

  20. Direct solar energy conversion and storage through coupling between photoelectrochemical and ferroelectric effects

    Directory of Open Access Journals (Sweden)

    Chi-Wei Lo

    2011-12-01

    Full Text Available Harvesting and storing solar energy has become more and more important. Current solid-state photovoltaic cells and conventional photoelectrochemical cells are not capable of directly storing the converted energy, which has to be facilitated by connecting to external storing devices. We demonstrate a device architecture that can convert and store solar energy in the electrical form within an intrinsically single structure. Mobile charge is internally stored, based on the coupling between photoelectrochemical and ferroelectric effects. The tested device architecture can be photo-charged under 1000 W/m2 of white light to an open-circuit voltage of 0.47V with a capacity of 37.62 mC/cm2. After removal of the light source, the mobile charge stored lasts more than 8 hours, and the open-circuit output voltage lasts more than 24 hours.

  1. Adaptive Training for Voice Conversion Based on Eigenvoices

    Science.gov (United States)

    Ohtani, Yamato; Toda, Tomoki; Saruwatari, Hiroshi; Shikano, Kiyohiro

    In this paper, we describe a novel model training method for one-to-many eigenvoice conversion (EVC). One-to-many EVC is a technique for converting a specific source speaker's voice into an arbitrary target speaker's voice. An eigenvoice Gaussian mixture model (EV-GMM) is trained in advance using multiple parallel data sets consisting of utterance-pairs of the source speaker and many pre-stored target speakers. The EV-GMM can be adapted to new target speakers using only a few of their arbitrary utterances by estimating a small number of adaptive parameters. In the adaptation process, several parameters of the EV-GMM to be fixed for different target speakers strongly affect the conversion performance of the adapted model. In order to improve the conversion performance in one-to-many EVC, we propose an adaptive training method of the EV-GMM. In the proposed training method, both the fixed parameters and the adaptive parameters are optimized by maximizing a total likelihood function of the EV-GMMs adapted to individual pre-stored target speakers. We conducted objective and subjective evaluations to demonstrate the effectiveness of the proposed training method. The experimental results show that the proposed adaptive training yields significant quality improvements in the converted speech.

  2. Direct conversion of root primordium into shoot meristem relies on timing of stem cell niche development.

    Science.gov (United States)

    Rosspopoff, Olga; Chelysheva, Liudmila; Saffar, Julie; Lecorgne, Lena; Gey, Delphine; Caillieux, Erwann; Colot, Vincent; Roudier, François; Hilson, Pierre; Berthomé, Richard; Da Costa, Marco; Rech, Philippe

    2017-04-01

    To understand how the identity of an organ can be switched, we studied the transformation of lateral root primordia (LRP) into shoot meristems in Arabidopsis root segments. In this system, the cytokinin-induced conversion does not involve the formation of callus-like structures. Detailed analysis showed that the conversion sequence starts with a mitotic pause and is concomitant with the differential expression of regulators of root and shoot development. The conversion requires the presence of apical stem cells, and only LRP at stages VI or VII can be switched. It is engaged as soon as cell divisions resume because their position and orientation differ in the converting organ compared with the undisturbed emerging LRP. By alternating auxin and cytokinin treatments, we showed that the root and shoot organogenetic programs are remarkably plastic, as the status of the same plant stem cell niche can be reversed repeatedly within a set developmental window. Thus, the networks at play in the meristem of a root can morph in the span of a couple of cell division cycles into those of a shoot, and back, through transdifferentiation. © 2017. Published by The Company of Biologists Ltd.

  3. Electro-optic transparent frequency conversion of a continuous light wave based on multistage phase modulation.

    Science.gov (United States)

    Hisatake, Shintaro; Kobayashi, Tetsuro

    2006-02-15

    Frequency conversion of a continuous light wave based on multistage phase modulation has been investigated both analytically and numerically. The proposed frequency-conversion process consists of three stages: (i) phase modulation and chirp compression to generate a pulse train, (ii) Doppler shift of the pulse center frequency in a second phase modulation, and (iii) demodulation of the pulse train. By controlling the modulation power we can select the destination frequency from an equally spaced grid separated by the modulation frequency. A conversion efficiency of approximately 40% has been numerically confirmed with respect to a destination frequency of +/- 50 channels. Carrier frequency conversion of an analog data stream is numerically demonstrated.

  4. High stability vector-based direct power control for DFIG-based wind turbine

    DEFF Research Database (Denmark)

    Zhu, Rongwu; Chen, Zhe; Wu, Xiaojie

    2015-01-01

    This paper proposes an improved vector-based direct power control (DPC) strategy for the doubly-fed induction generator (DFIG)-based wind energy conversion system. Based on the small signal model, the proposed DPC improves the stability of the DFIG, and avoids the DFIG operating in the marginal...... stable region (the real part of eigenvalue is equal to zero). The vector-based DPC combines with a space vector modulation technique to achieve a constant switching frequency. The simulation and experimental results clearly validate the effectiveness and feasibility of the proposed vector-based DPC...

  5. 640 Gbit/s RZ-to-NRZ format conversion based on optical phase filtering

    DEFF Research Database (Denmark)

    Maram, Reza; Kong, Deming; Galili, Michael

    2014-01-01

    We propose a novel approach for all optical RZ-to-NRZ conversion based on optical phase filtering. The proposed concept is experimentally validated through format conversion of a 640 Gbit/s coherent RZ signal to NRZ signal using a simple phase filter implemented by a commercial optical waveshaper....

  6. Light-triggered thermoelectric conversion based on a carbon nanotube-polymer hybrid gel.

    Science.gov (United States)

    Miyako, Eijiro; Nagata, Hideya; Funahashi, Ryoji; Hirano, Ken; Hirotsu, Takahiro

    2009-01-01

    Lights? Nanotubes? Action! A hydrogel comprising lysozymes, poly(ethylene glycol), phospholipids, and functionalized single-walled carbon nanotubes is employed for light-driven thermoelectric conversion. A photoinduced thermoelectric conversion module based on the hydrogel functions as a novel electric power generator (see image). This concept may find application in various industries, such as robotics and aerospace engineering.

  7. A data acquisition system for gas proportional detectors with delay line readout based on space-time-space conversion

    CERN Document Server

    Raad-Iseli, C D; Golding, F; Boulin, C; Epstein, A; Beloeuvre, E; Gabriel, A; Koch, M H J

    2001-01-01

    A NIM module for delay line readout of linear gas proportional X-ray or neutron detectors based on time to space conversion is presented. Each of the 16 ASICs in the module contains a delay line with 64 elements each connected to a 24 bit-counter. Readout of the coincidence of signals travelling in opposite directions on the delay line and incrementation of the counters is triggered by the prompt anode signal so that simultaneous events are correctly processed. Transfer of the contents of the 1024 individual counters to a histogramming device at the end of a time frame can be as short as 60 mu s. With continuous delay lines the total conversion time equals the transit time of the delay line in the detector, whereas with segmented delay lines the total conversion time is around 20 ns.

  8. New colorimetric screening assays for the directed evolution of fungal laccases to improve the conversion of plant biomass.

    Science.gov (United States)

    Pardo, Isabel; Chanagá, Xiomara; Vicente, Ana Isabel; Alcalde, Miguel; Camarero, Susana

    2013-10-26

    Fungal laccases are multicopper oxidases with huge applicability in different sectors. Here, we describe the development of a set of high-throughput colorimetric assays for screening laccase libraries in directed evolution studies. Firstly, we designed three colorimetric assays based on the oxidation of sinapic acid, acetosyringone and syringaldehyde with λmax of 512, 520 and 370 nm, respectively. These syringyl-type phenolic compounds are released during the degradation of lignocellulose and can act as laccase redox mediators. The oxidation of the three compounds by low and high-redox potential laccases evolved in Saccharomyces cerevisiae produced quantifiable and linear responses, with detection limits around 1 mU/mL and CV values below 16%. The phenolic substrates were also suitable for pre-screening mutant libraries on solid phase format. Intense colored-halos were developed around the yeast colonies secreting laccase. Furthermore, the oxidation of violuric acid to its iminoxyl radical (λmax of 515 nm and CV below 15%) was devised as reporter assay for laccase redox potential during the screening of mutant libraries from high-redox potential laccases. Finally, we developed three dye-decolorizing assays based on the enzymatic oxidation of Methyl Orange (470 nm), Evans Blue (605 nm) and Remazol Brilliant Blue (640 nm) giving up to 40% decolorization yields and CV values below 18%. The assays were reliable for direct measurement of laccase activity or to indirectly explore the oxidation of mediators that do not render colored products (but promote dye decolorization). Every single assay reported in this work was tested by exploring mutant libraries created by error prone PCR of fungal laccases secreted by yeast. The high-throughput screening methods reported in this work could be useful for engineering laccases for different purposes. The assays based on the oxidation of syringyl-compounds might be valuable tools for tailoring laccases precisely enhanced to aid

  9. The direct conversion of synthesis gas to chemicals / Ernest du Toit

    OpenAIRE

    Du Toit, Ernest

    2002-01-01

    The catalytic conversion of synthesis gas, obtainable from the processing of coal, biomass or natural gas, to a complex hydrocarbon product stream can be achieved via the Fischer-Tropsch process. The Fischer-Tropsch synthesis process has evolved from being mainly a fuel producing process in the early 1950's to that of a solvent and speciality wax production process towards the end of the 1970's. From the early 1980's there has been a clear shift towards the production of commod...

  10. Research Update: Direct conversion of amorphous carbon into diamond at ambient pressures and temperatures in air

    International Nuclear Information System (INIS)

    Narayan, Jagdish; Bhaumik, Anagh

    2015-01-01

    We report on fundamental discovery of conversion of amorphous carbon into diamond by irradiating amorphous carbon films with nanosecond lasers at room-temperature in air at atmospheric pressure. We can create diamond in the form of nanodiamond (size range <100 nm) and microdiamond (>100 nm). Nanosecond laser pulses are used to melt amorphous diamondlike carbon and create a highly undercooled state, from which various forms of diamond can be formed upon cooling. The quenching from the super undercooled state results in nucleation of nanodiamond. It is found that microdiamonds grow out of highly undercooled state of carbon, with nanodiamond acting as seed crystals

  11. Performance of conversion efficiency of a crystalline silicon solar cell with base doping density

    Directory of Open Access Journals (Sweden)

    Gokhan Sahin

    Full Text Available In this study, we investigate theoretically the electrical parameters of a crystalline silicon solar cell in steady state. Based on a one-dimensional modeling of the cell, the short circuit current density, the open circuit voltage, the shunt and series resistances and the conversion efficiency are calculated, taking into account the base doping density. Either the I-V characteristic, series resistance, shunt resistance and conversion efficiency are determined and studied versus base doping density. The effects applied of base doping density on these parameters have been studied. The aim of this work is to show how short circuit current density, open circuit voltage and parasitic resistances are related to the base doping density and to exhibit the role played by those parasitic resistances on the conversion efficiency of the crystalline silicon solar. Keywords: Crystalline silicon solar cell, Base doping density, Series resistance, Shunt resistance, Conversion efficiency

  12. Archetype-based conversion of EHR content models: pilot experience with a regional EHR system

    Science.gov (United States)

    2009-01-01

    Background Exchange of Electronic Health Record (EHR) data between systems from different suppliers is a major challenge. EHR communication based on archetype methodology has been developed by openEHR and CEN/ISO. The experience of using archetypes in deployed EHR systems is quite limited today. Currently deployed EHR systems with large user bases have their own proprietary way of representing clinical content using various models. This study was designed to investigate the feasibility of representing EHR content models from a regional EHR system as openEHR archetypes and inversely to convert archetypes to the proprietary format. Methods The openEHR EHR Reference Model (RM) and Archetype Model (AM) specifications were used. The template model of the Cambio COSMIC, a regional EHR product from Sweden, was analyzed and compared to the openEHR RM and AM. This study was focused on the convertibility of the EHR semantic models. A semantic mapping between the openEHR RM/AM and the COSMIC template model was produced and used as the basis for developing prototype software that performs automated bi-directional conversion between openEHR archetypes and COSMIC templates. Results Automated bi-directional conversion between openEHR archetype format and COSMIC template format has been achieved. Several archetypes from the openEHR Clinical Knowledge Repository have been imported into COSMIC, preserving most of the structural and terminology related constraints. COSMIC templates from a large regional installation were successfully converted into the openEHR archetype format. The conversion from the COSMIC templates into archetype format preserves nearly all structural and semantic definitions of the original content models. A strategy of gradually adding archetype support to legacy EHR systems was formulated in order to allow sharing of clinical content models defined using different formats. Conclusion The openEHR RM and AM are expressive enough to represent the existing clinical

  13. Direct Catalytic Conversion of Cellulose to 5-Hydroxymethylfurfural Using Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Sanan Eminov

    2016-10-01

    Full Text Available Cellulose is the single largest component of lignocellulosic biomass and is an attractive feedstock for a wide variety of renewable platform chemicals and biofuels, providing an alternative to petrochemicals and petrofuels. This potential is currently limited by the existing methods of transforming this poorly soluble polymer into useful chemical building blocks, such as 5-hydroxymethylfurfural (HMF. Ionic liquids have been used successfully to separate cellulose from the other components of lignocellulosic biomass and so the use of the same medium for the challenging transformation of cellulose into HMF would be highly attractive for the development of the biorefinery concept. In this report, ionic liquids based on 1-butyl-3-methylimidazolium cations [C4C1im]+ with Lewis basic (X = Cl− and Brønsted acidic (X = HSO4− anions were used to investigate the direct catalytic transformation of cellulose to HMF. Variables probed included the composition of the ionic liquid medium, the metal catalyst, and the reaction conditions (temperature, substrate concentration. Lowering the cellulose loading and optimising the temperature achieved a 58% HMF yield after only one hour at 150 °C using a 7 mol % loading of the CrCl3 catalyst. This compares favourably with current literature procedures requiring much longer reactions times or approaches that are difficult to scale such as microwave irradiation.

  14. Directed surfaces structures and interfaces for enhanced electrocatalyst activity, selectivity, and stability for energy conversion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Jaramillo, Thomas F. [Stanford Univ., CA (United States). Dept. of Chemical Engineering. Shriram Center

    2016-04-20

    In this project, we have employed a systematic approach to develop active, selective, and stable catalyst materials for important electrochemical reactions involving energy conversion. In particular, we have focused our attention on developing active catalyst materials for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). HER: We have synthesized and investigated several highly active and acid stable non-precious metal HER catalysts, including: [Mo3S13]2- nanoclusters (Nature Chemistry, 2014) and molybdenum phosphosulfide (MoP|S) (Angewandte Chemie, 2014). We have also aimed to engineer these catalyst formulations in a membrane electrode assembly (MEA) for fundamental studies of water electrolysis at high current densities, approximately 1 A/cm2 (ChemSusChem, 2015). We furthermore investigated transition metal phosphide (TMP) catalysts for HER by a combined experimental–theoretical approach (Energy & Environmental Science, 2015). By synthesizing different TMPs and comparing experimentally determined HER activities with the hydrogen adsorption free energies, ΔGH, calculated by density functional theory, we showed that the TMPs follow a volcano relationship for the HER. Using our combined experimental–theoretical model, we predicted that the mixed metal TMP, Fe0.5Co0.5P, should have a near-optimal ΔGH. We synthesized several mixtures of Co and Fe phosphides alloys and confirmed that Fe0.5Co0.5P exhibits the highest HER activity of the investigated TMPs (Energy & Environmental Science, 2015). The understanding gained as to how to improve catalytic activity for the HER, particularly for non-precious metal materials, is important to DOE targets for sustainable H2 production. OER: We have developed a SrIrO3/IrOx catalyst for acidic conditions (submitted, 2016). The Sr

  15. Hot-electron-based solar energy conversion with metal-semiconductor nanodiodes

    Science.gov (United States)

    Lee, Young Keun; Lee, Hyosun; Lee, Changhwan; Hwang, Euyheon; Park, Jeong Young

    2016-06-01

    Energy dissipation at metal surfaces or interfaces between a metal and a dielectric generally results from elementary excitations, including phonons and electronic excitation, once external energy is deposited to the surface/interface during exothermic chemical processes or an electromagnetic wave incident. In this paper, we outline recent research activities to develop energy conversion devices based on hot electrons. We found that photon energy can be directly converted to hot electrons and that hot electrons flow through the interface of metal-semiconductor nanodiodes where a Schottky barrier is formed and the energy barrier is much lower than the work function of the metal. The detection of hot electron flow can be successfully measured using the photocurrent; we measured the photoyield of photoemission with incident photons-to-current conversion efficiency (IPCE). We also show that surface plasmons (i.e. the collective oscillation of conduction band electrons induced by interaction with an electromagnetic field) are excited on a rough metal surface and subsequently decay into secondary electrons, which gives rise to enhancement of the IPCE. Furthermore, the unique optical behavior of surface plasmons can be coupled with dye molecules, suggesting the possibility for producing additional channels for hot electron generation.

  16. Engineering Saccharomyces cerevisiae for direct conversion of raw, uncooked or granular starch to ethanol.

    Science.gov (United States)

    Görgens, Johann F; Bressler, David C; van Rensburg, Eugéne

    2015-01-01

    The production of raw starch-degrading amylases by recombinant Saccharomyces cerevisiae provides opportunities for the direct hydrolysis and fermentation of raw starch to ethanol without cooking or exogenous enzyme addition. Such a consolidated bioprocess (CBP) for raw starch fermentation will substantially reduce costs associated with energy usage and commercial granular starch hydrolyzing (GSH) enzymes. The core purpose of this review is to provide comprehensive insight into the physiological impact of recombinant amylase production on the ethanol-producing yeast. Key production parameters, based on outcomes from modifications to the yeast genome and levels of amylase production, were compared to key benchmark data. In turn, these outcomes are of significance from a process point of view to highlight shortcomings in the current state of the art of raw starch fermentation yeast compared to a set of industrial standards. Therefore, this study provides an integrated critical assessment of physiology, genetics and process aspects of recombinant raw starch fermenting yeast in relation to presently used technology. Various approaches to strain development were compared on a common basis of quantitative performance measures, including the extent of hydrolysis, fermentation-hydrolysis yield and productivity. Key findings showed that levels of α-amylase required for raw starch hydrolysis far exceeded enzyme levels for soluble starch hydrolysis, pointing to a pre-requisite for excess α-amylase compared to glucoamylase for efficient raw starch hydrolysis. However, the physiological limitations of amylase production by yeast, requiring high biomass concentrations and long cultivation periods for sufficient enzyme accumulation under anaerobic conditions, remained a substantial challenge. Accordingly, the fermentation performance of the recombinant S. cerevisiae strains reviewed in this study could not match the performance of conventional starch fermentation processes

  17. Potentiality of Yeasts in the Direct Conversion of Starchy Materials to Ethanol and Its Relevance in the New Millennium

    Science.gov (United States)

    Reddy, L. V. A.; Reddy, O. V. S.; Basappa, S. C.

    In recent years, the use of renewable and abundantly available starchy and cellulosic materials for industrial production of ethanol is gaining importance, in view of the fact, that ethanol is one of the most prospective future motor fuels, that can be expected to replace fossil fuels, which are fast depleting in the world scenario. Although, the starch and the starchy substrates could be converted successfully to ethanol on industrial scales by the use of commercial amylolytic enzymes and yeast fermentation, the cost of production is rather very high. This is mainly due to the non-enzymatic and enzymatic conversion (gelatinization, liquefaction and saccharification) of starch to sugars, which costs around 20 % of the cost of production of ethanol from starch. In this context, the use of amylolytic yeasts, that can directly convert starch to ethanol by a single step, are potentially suited to reduce the cost of production of ethanol from starch. Research advances made in this direction have shown encouraging results, both in terms of identifying the potentially suited yeasts for the purpose and also their economic ethanol yields. This chapter focuses on the types of starch and starchy substrates and their digestion to fermentable sugars, optimization of fermentation conditions to ethanol from starch, factors that affect starch fermentation, potential amylolytic yeasts which can directly convert starch to ethanol, genetic improvement of these yeasts for better conversion efficiency and their future economic prospects in the new millennium.

  18. Using Carbon-Based Nanomaterials and Microscale Geometry for Enhanced Thermionic Energy Conversion in Space Applications

    Data.gov (United States)

    National Aeronautics and Space Administration — The hypothesis of this research is that using carbon-based nanomaterials (CBN) electrodes in a microscale thermionic energy conversion (TEC) device operated at...

  19. Vector mode conversion based on tilted fiber Bragg grating in ring-core fibers

    Science.gov (United States)

    Mi, Yuean; Ren, Guobin; Gao, Yixiao; Li, Haisu; Zhu, Bofeng; Liu, Yu

    2018-03-01

    We propose a vector mode conversion approach based on tilted fiber Bragg grating (TFBG) written in ring-core fiber with effective separation of eigenmodes. The mode coupling properties of TFBG are numerically investigated. It is shown that under the constraint of phase matching, the conversion of high-order vector modes could be achieved at specific wavelengths. Moreover, the polarization of incident light and tilt angle of TFBG play critical roles in mode coupling process. The proposed TFBG provides an efficient method to realize high-order vector mode conversion, and it shows great potential for fibers based OAM beam generation and fiber lasers with vortex beams output.

  20. Recovery Act. Demonstration of a Pilot Integrated Biorefinery for the Efficient, Direct Conversion of Biomass to Diesel Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Schuetzle, Dennis [Renewable Energy Institute International, Sacramentao, CA (United States); Tamblyn, Greg [Renewable Energy Institute International, Sacramentao, CA (United States); Caldwell, Matt [Renewable Energy Institute International, Sacramentao, CA (United States); Hanbury, Orion [Renewable Energy Institute International, Sacramentao, CA (United States); Schuetzle, Robert [Greyrock Energy, Sacramento, CA (United States); Rodriguez, Ramer [Greyrock Energy, Sacramento, CA (United States); Johnson, Alex [Red Lion Bio-Energy, Toledo, OH (United States); Deichert, Fred [Red Lion Bio-Energy, Toledo, OH (United States); Jorgensen, Roger [Red Lion Bio-Energy, Toledo, OH (United States); Struble, Doug [Red Lion Bio-Energy, Toledo, OH (United States)

    2015-05-12

    The Renewable Energy Institute International, in collaboration with Greyrock Energy and Red Lion Bio-Energy (RLB) has successfully demonstrated operation of a 25 ton per day (tpd) nameplate capacity, pilot, pre-commercial-scale integrated biorefinery (IBR) plant for the direct production of premium, “drop-in”, synthetic fuels from agriculture and forest waste feedstocks using next-generation thermochemical and catalytic conversion technologies. The IBR plant was built and tested at the Energy Center, which is located in the University of Toledo Medical Campus in Toledo, Ohio.

  1. The Fusion Driven Rocket: Nuclear Propulsion through Direct Conversion of Fusion Energy

    Data.gov (United States)

    National Aeronautics and Space Administration — The Fusion Driven rocket (FDR) represents a revolutionary approach to fusion propulsion where the power source releases its energy directly into the propellant, not...

  2. Polarization Insensitive Wavelength Conversion Based on Four-Wave Mixing in a Silicon Nanowire

    DEFF Research Database (Denmark)

    Pu, Minhao; Hu, Hao; Peucheret, Christophe

    2012-01-01

    We experimentally demonstrate, for the first time, polarization-insensitive wavelength conversion of a 10 Gb/s NRZ-OOK data signal based on four-wave mixing in a silicon nanowire with bit-error rate measurements.......We experimentally demonstrate, for the first time, polarization-insensitive wavelength conversion of a 10 Gb/s NRZ-OOK data signal based on four-wave mixing in a silicon nanowire with bit-error rate measurements....

  3. Conversational Implicature of Peanuts Comic Strip Based on Grice’s Maxim Theory

    Directory of Open Access Journals (Sweden)

    Muhartoyo Muhartoyo

    2013-04-01

    Full Text Available This article discusses about conversational implicature that occurs in Peanuts comic strips. The objectives of this study are to find out the implied meaning in the conversation between Charlie Brown with Lucy van Pelt and Lucy van Pelt with Linus van Pelt to evaluate the existence of maxim flouting and maxim violating in those conversations in relation to the four maxims such as quantity, quality, relation, and manner. Likewise, this study attempts to find out the reason for using conversational implicature in a comic strip. The writers uses a qualitative method with library research concerning to Grice’s maxim theory to analyze the conversational implicature. Based on the analysis, it can be concluded that all the comics that comprise 14 comics generate conversational implicature since all the characters breach rules of maxim. The result of this analysis shows that flouting maxim of manner has the highest occurrence of conversational implicature and the least occurrences belong to flouting maxim of relation and violating maxim of quantity. Moreover, the writers concludes that to make a successful communication ideally the speaker and the hearer to cooperate in the conversation by saying explicitly so the hearer can grasp the meaning as the goal of communication is to deliver a message to the hearer.  

  4. Design of generic coal conversion facilities: Process release---Direct coal liquefaction

    Energy Technology Data Exchange (ETDEWEB)

    1991-09-01

    The direct liquefaction portion of the PETC generic direct coal liquefaction process development unit (PDU) is being designed to provide maximum operating flexibility. The PDU design will permit catalytic and non-catalytic liquefaction concepts to be investigated at their proof-of-the-concept stages before any larger scale operations are attempted. The principal variations from concept to concept are reactor configurations and types. These include thermal reactor, ebullating bed reactor, slurry phase reactor and fixed bed reactor, as well as different types of catalyst. All of these operating modes are necessary to define and identify the optimum process conditions and configurations for determining improved economical liquefaction technology.

  5. Power conversion and quality of the Santa Clara 2 MW direct carbonate fuel cell demonstration plant

    Energy Technology Data Exchange (ETDEWEB)

    Skok, A.J. [Fuel Cell Engineering Corp., Danbury, CT (United States); Abueg, R.Z. [Basic Measuring Instruments, Santa Clara, CA (United States); Schwartz, P. [Fluor Daniel, Inc., Irvine, CA (United States)] [and others

    1996-12-31

    The Santa Clara Demonstration Project (SCDP) is the first application of a commercial-scale carbonate fuel cell power plant on a US electric utility system. It is also the largest fuel cell power plant ever operated in the United States. The 2MW plant, located in Santa Clara, California, utilizes carbonate fuel cell technology developed by Energy Research Corporation (ERC) of Danbury, Connecticut. The ultimate goal of a fuel cell power plant is to deliver usable power into an electrical distribution system. The power conversion sub-system does this for the Santa Clara Demonstration Plant. A description of this sub-system and its capabilities follows. The sub-system has demonstrated the capability to deliver real power, reactive power and to absorb reactive power on a utility grid. The sub-system can be operated in the same manner as a conventional rotating generator except with enhanced capabilities for reactive power. Measurements demonstrated the power quality from the plant in various operating modes was high quality utility grade power.

  6. Directed plant cell-wall accumulation of iron: embedding co-catalyst for efficient biomass conversion

    Science.gov (United States)

    Chien-Yuan Lin; Joseph E. Jakes; Bryon S. Donohoe; Peter N. Ciesielski; Haibing Yang; Sophie-Charlotte Gleber; Stefan Vogt; Shi-You Ding; Wendy A. Peer; Angus S. Murphy; Maureen C. McCann; Michael E. Himmel; Melvin P. Tucker; Hui Wei

    2016-01-01

    Background: Plant lignocellulosic biomass is an abundant, renewable feedstock for the production of biobased fuels and chemicals. Previously, we showed that iron can act as a co-catalyst to improve the deconstruction of lignocellulosic biomass. However, directly adding iron catalysts into biomass prior to pretreatment is diffusion limited,...

  7. Improved direct torque control of an induction generator used in a wind conversion system connected to the grid.

    Science.gov (United States)

    Abdelli, Radia; Rekioua, Djamila; Rekioua, Toufik; Tounzi, Abdelmounaïm

    2013-07-01

    This paper presents a modulated hysteresis direct torque control (MHDTC) applied to an induction generator (IG) used in wind energy conversion systems (WECs) connected to the electrical grid through a back-to-back converter. The principle of this strategy consists in superposing to the torque reference a triangular signal, as in the PWM strategy, with the desired switching frequency. This new modulated reference is compared to the estimated torque by using a hysteresis controller as in the classical direct torque control (DTC). The aim of this new approach is to lead to a constant frequency and low THD in grid current with a unit power factor and a minimum voltage variation despite the wind variation. To highlight the effectiveness of the proposed method, a comparison was made with classical DTC and field oriented control method (FOC). The obtained simulation results, with a variable wind profile, show an adequate dynamic of the conversion system using the proposed method compared to the classical approaches. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

  8. A novel PWM control for a bi-directional full-bridge DC-DC converter with smooth conversion mode transitions

    Science.gov (United States)

    Lorentz, V. R. H.; Schwarzmann, H.; März, M.; Bauer, A. J.; Ryssel, H.; Frey, L.; Poure, P.; Braun, F.

    2011-08-01

    A novel CMOS integrated pulse-width modulation (PWM) control circuit allowing smooth transitions between conversion modes in full-bridge based bi-directional DC-DC converters operating at high switching frequencies is presented. The novel PWM control circuit is able to drive full-bridge based DC-DC converters performing step-down (i.e. buck) and step-up (i.e. boost) voltage conversion in both directions, thus allowing charging and discharging of the batteries in mobile systems. It provides smooth transitions between buck, buck-boost and boost modes. Additionally, the novel PWM control loop circuit uses a symmetrical triangular carrier, which overcomes the necessity of using an output phasing circuit previously required in PWM controllers based on sawtooth oscillators. The novel PWM control also enables to build bi-directional DC-DC converters operating at high switching frequencies (i.e. up to 10 MHz and above). Finally, the proposed PWM control circuit also allows the use of an average lossless inductor-current sensor for sensing the average load current even at very high switching frequencies. In this article, the proposed PWM control circuit is modelled and the integrated CMOS schematic is given. The corresponding theory is analysed and presented in detail. The circuit simulations realised in the Cadence Spectre software with a commercially available 0.18 µm mixed-signal CMOS technology from UMC are shown. The PWM control circuit was implemented in a monolithic integrated bi-directional CMOS DC-DC converter ASIC prototype. The fabricated prototype was tested experimentally and has shown performances in accordance with the theory.

  9. Palmprint Recognition Based on Complete Direction Representation.

    Science.gov (United States)

    Jia, Wei; Zhang, Bob; Lu, Jingting; Zhu, Yihai; Zhao, Yang; Zuo, Wangmeng; Ling, Haibin

    2017-05-18

    Direction information serves as one of the most important features for palmprint recognition. In the past decade, many effective direction representation (DR)-based methods have been proposed and achieved promising recognition performance. However, due to an incomplete understanding for DR, these methods only extract DR in one direction level and one scale. Hence, they did not fully utilized all potentials of DR. In addition, most researchers only focused on the DR extraction in spatial coding domain, and rarely considered the methods in frequency domain. In this paper, we propose a general framework for DR-based method named Complete Direction Representation (CDR), which reveals DR by a comprehensive and complete way. Different from traditional methods, CDR emphasizes the use of direction information with strategies of multi-scale, multi-direction level, multi-region, as well as feature selection or learning. This way, CDR subsumes previous methods as special cases. Moreover, thanks to its new insight, CDR can guide the design of new DR-based methods toward better performance. Motived this way, we propose a novel palmprint recognition algorithm in frequency domain. Firstly, we extract CDR using multi-scale modified finite radon transformation (MFRAT). Then, an effective correlation filter, namely Band-Limited Phase-Only Correlation (BLPOC), is explored for pattern matching. To remove feature redundancy, the Sequential Forward Selection (SFS) method is used to select a small number of CDR images. Finally, the matching scores obtained from different selected features are integrated using score-level-fusion. Experiments demonstrate that our method can achieve better recognition accuracy than the other state-of-the-art methods. More importantly, it has fast matching speed, making it quite suitable for the large-scale identification applications.

  10. A direct method for string to deterministic finite automaton conversion for fast text searching

    Energy Technology Data Exchange (ETDEWEB)

    Berlin, G.J.

    1991-12-31

    This paper describes a simple technique for generating a minimum state deterministic finite automation (DFA) directly from a restricted set of regular expressions. The resulting DFA is used for string searches that do not alter the target text and require only a single pass through the input. The technique is used for very fast, mixed or same case, single or multiple string searches. The technique is also capable of directly converting multiple strings with wild card character specifiers by constructing parallel DFAs. Construction of the automation is performed in a time proportional to the length of the regular expression. Algorithms are given for construction of the automatons and recognizers. Although the regular expression to DFA parser does not support all classes of regular expressions, it supports a sufficient subset to make it useful for the most commonly encountered text searching functions.

  11. A direct method for string to deterministic finite automaton conversion for fast text searching

    Energy Technology Data Exchange (ETDEWEB)

    Berlin, G.J.

    1991-01-01

    This paper describes a simple technique for generating a minimum state deterministic finite automation (DFA) directly from a restricted set of regular expressions. The resulting DFA is used for string searches that do not alter the target text and require only a single pass through the input. The technique is used for very fast, mixed or same case, single or multiple string searches. The technique is also capable of directly converting multiple strings with wild card character specifiers by constructing parallel DFAs. Construction of the automation is performed in a time proportional to the length of the regular expression. Algorithms are given for construction of the automatons and recognizers. Although the regular expression to DFA parser does not support all classes of regular expressions, it supports a sufficient subset to make it useful for the most commonly encountered text searching functions.

  12. Conversion of Goat Fibroblasts into Lineage-Specific Cells Using a Direct Reprogramming Strategy.

    Science.gov (United States)

    Guo, Yanjie; Yu, Tong; Lei, Lei; Duan, Anqin; Ma, Xiaoling; Wang, Huayan

    2017-05-01

    Direct reprogramming is an efficient strategy to convert one cell type to another. In this study, due to the failure of maintaining the undifferentiated state of goat embryotic stem- and induced pluripotent stem-like cells in vitro, we explored an alternative way to directly convert goat fibroblasts to lineage-specific cells. The 'Yamanaka factors' was ectopically expressed in fibroblasts for a short term to situate cells in a metastable state. By culturing with lineage-specific media for 1-2 weeks, the cardiomyocyte-like cells and neurocyte-like cells were generated and confirmed by the quantitative RT-PCR and immunocytochemical staining. The metastable-state cells could also be converted into oocyte-like cells (OLCs) after culturing in media with retinoic acid (RA) and bovine follicular fluid (bFF) for 2-3 weeks. The generated OLCs were surrounded by cumulus granulosa cell-like cells and formed a structure resembling goat cumulus-oocyte complex from ovaries. This primary follicular structure could be developed further in oocyte mature medium and expressed germ cell-specific markers. In addition, we found that the induction efficiency was higher and OLC cell size was bigger in bFF than in RA treatment. Altogether, the direct reprogramming of goat fibroblasts into lineage-specific cells can facilitate stem cell research in domestic animals. © 2016 Japanese Society of Animal Science.

  13. Image-based reflectance conversion of ASTER and IKONOS ...

    African Journals Online (AJOL)

    Spectral signatures derived from different image-based models for ASTER and IKONOS were inspected visually as first departure. This was followed by comparison of the total accuracy and Kappa index computed from supervised classification of images that were derived from different image-based atmospheric correction ...

  14. A direct current rectification scheme for microwave space power conversion using traveling wave electron acceleration

    Science.gov (United States)

    Manning, Robert M.

    1993-01-01

    The formation of the Vision-21 conference held three years ago allowed the present author to reflect and speculate on the problem of converting electromagnetic energy to a direct current by essentially reversing the process used in traveling wave tubes that converts energy in the form of a direct current to electromagnetic energy. The idea was to use the electric field of the electromagnetic wave to produce electrons through the field emission process and accelerate these electrons by the same field to produce an electric current across a large potential difference. The acceleration process was that of cyclotron auto-resonance. Since that time, this rather speculative ideas has been developed into a method that shows great promise and for which a patent is pending and a prototype design will be demonstrated in a potential laser power beaming application. From the point of view of the author, a forum such as Vision-21 is becoming an essential component in the rather conservative climate in which our initiatives for space exploration are presently formed. Exchanges such as Vision-21 not only allows us to deviate from the 'by-the-book' approach and rediscover the ability and power in imagination, but provides for the discussion of ideas hitherto considered 'crazy' so that they may be given the change to transcend from the level of eccentricity to applicability.

  15. Dynamics-based centrality for directed networks.

    Science.gov (United States)

    Masuda, Naoki; Kori, Hiroshi

    2010-11-01

    Determining the relative importance of nodes in directed networks is important in, for example, ranking websites, publications, and sports teams, and for understanding signal flows in systems biology. A prevailing centrality measure in this respect is the PageRank. In this work, we focus on another class of centrality derived from the Laplacian of the network. We extend the Laplacian-based centrality, which has mainly been applied to strongly connected networks, to the case of general directed networks such that we can quantitatively compare arbitrary nodes. Toward this end, we adopt the idea used in the PageRank to introduce global connectivity between all the pairs of nodes with a certain strength. Numerical simulations are carried out on some networks. We also offer interpretations of the Laplacian-based centrality for general directed networks in terms of various dynamical and structural properties of networks. Importantly, the Laplacian-based centrality defined as the stationary density of the continuous-time random walk with random jumps is shown to be equivalent to the absorption probability of the random walk with sinks at each node but without random jumps. Similarly, the proposed centrality represents the importance of nodes in dynamics on the original network supplied with sinks but not with random jumps.

  16. Direct Conversion of Carbohydrates into Ethyl Levulinate with Potassium Phosphotungstate as an Efficient Catalyst

    Directory of Open Access Journals (Sweden)

    Shiqiang Zhao

    2015-11-01

    Full Text Available A series of metal-modified phosphotungstates were prepared and performed for direct synthesis of ethyl levulinate from fructose in ethanol. Considering the cost of catalysts, catalytic activity of catalysts, and easy separation of catalysts together, K-HPW-1 was chosen as the most suitable catalyst for synthesis of ethyl levulinate from fructose. A high ethyl levulinate yield of 64.6 mol% was obtained at 150 °C within 2 h in ethanol. The introduction of low polar toluene as a co-solvent improved the yield of ethyl levulinate to 68.7 mol%. The recovered catalyst remained high activity with the yield of ethyl levulinate converted from fructose above 50 mol% after being used five times. Moreover, the generality of the catalyst was further demonstrated by glucose, sucrose, inulin, and cellulose with ethyl levulinate yielding 14.5, 35.4, 52.3, and 14.8 mol%, respectively.

  17. Technology of direct conversion for mirror reactor end-loss plasma

    International Nuclear Information System (INIS)

    Barr, W.L.; Moir, R.W.

    1980-01-01

    Design concepts are presented for plasma direct convertors (PDC) intended primarily for use on the end-loss plasma from tandem-mirror reactors. Recent experimental results confirm most of these design concepts. Both a one-stage and a two-stage PDC were tested in reactor-like conditions using a 100-kV, 6-kW ion beam. In a separate test on the end of the TMX machine, a single stage PDC recovered 79 W for a net efficiency of 50%. Tandem mirror devices are well suited to PDC. The high minimum energy of the end-loss ions, the magnetic expansion outside the mirrors, and the vacuum conditions in the end tanks required by the confined plasma, all preexist. The inclusion of a PDC is therefore a rather small addition. These facts and the scale parameters for a PDC are discussed

  18. Study of molybdenum/lanthanum-based composite conversion coatings on AZ31 magnesium alloy

    International Nuclear Information System (INIS)

    Yang Lihui; Li Junqing; Lin Cunguo; Zhang Milin; Wu Jianhua

    2011-01-01

    The molybdenum/lanthanum-based (Mo/La) composite conversion coating on AZ31 magnesium alloy was investigated and the corrosion resistance was evaluated as well. The morphology, composition and corrosion resistance of the coating were studied by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and potentiodynamic polarization analysis, respectively. The results revealed that the conversion coating consisted of spherical nodular particles, which was mainly composed of Mo, La, O and Mg. After conversion treatment the corrosion potential shifts about 500 mV positively, and the corrosion current density decreases two orders of magnitude. The corrosion resistance of AZ31 alloy is remarkably improved by Mo/La composite conversion coating.

  19. From Carbon-Based Nanotubes to Nanocages for Advanced Energy Conversion and Storage.

    Science.gov (United States)

    Wu, Qiang; Yang, Lijun; Wang, Xizhang; Hu, Zheng

    2017-02-21

    Carbon-based nanomaterials have been the focus of research interests in the past 30 years due to their abundant microstructures and morphologies, excellent properties, and wide potential applications, as landmarked by 0D fullerene, 1D nanotubes, and 2D graphene. With the availability of high specific surface area (SSA), well-balanced pore distribution, high conductivity, and tunable wettability, carbon-based nanomaterials are highly expected as advanced materials for energy conversion and storage to meet the increasing demands for clean and renewable energies. In this context, attention is usually attracted by the star material of graphene in recent years. In this Account, we overview our studies on carbon-based nanotubes to nanocages for energy conversion and storage, including their synthesis, performances, and related mechanisms. The two carbon nanostructures have the common features of interior cavity, high conductivity, and easy doping but much different SSAs and pore distributions, leading to different performances. We demonstrated a six-membered-ring-based growth mechanism of carbon nanotubes (CNTs) with benzene precursor based on the structural similarity of the benzene ring to the building unit of CNTs. By this mechanism, nitrogen-doped CNTs (NCNTs) with homogeneous N distribution and predominant pyridinic N were obtained with pyridine precursor, providing a new kind of support for convenient surface functionalization via N-participation. Accordingly, various transition-metal nanoparticles were directly immobilized onto NCNTs without premodification. The so-constructed catalysts featured high dispersion, narrow size distribution and tunable composition, which presented superior catalytic performances for energy conversions, for example, the oxygen reduction reaction (ORR) and methanol oxidation in fuel cells. With the advent of the new field of carbon-based metal-free electrocatalysts, we first extended ORR catalysts from the electron-rich N-doped to the

  20. Direct conversion of CO2 into liquid fuels with high selectivity over a bifunctional catalyst

    Science.gov (United States)

    Gao, Peng; Li, Shenggang; Bu, Xianni; Dang, Shanshan; Liu, Ziyu; Wang, Hui; Zhong, Liangshu; Qiu, Minghuang; Yang, Chengguang; Cai, Jun; Wei, Wei; Sun, Yuhan

    2017-10-01

    Although considerable progress has been made in carbon dioxide (CO2) hydrogenation to various C1 chemicals, it is still a great challenge to synthesize value-added products with two or more carbons, such as gasoline, directly from CO2 because of the extreme inertness of CO2 and a high C-C coupling barrier. Here we present a bifunctional catalyst composed of reducible indium oxides (In2O3) and zeolites that yields a high selectivity to gasoline-range hydrocarbons (78.6%) with a very low methane selectivity (1%). The oxygen vacancies on the In2O3 surfaces activate CO2 and hydrogen to form methanol, and C-C coupling subsequently occurs inside zeolite pores to produce gasoline-range hydrocarbons with a high octane number. The proximity of these two components plays a crucial role in suppressing the undesired reverse water gas shift reaction and giving a high selectivity for gasoline-range hydrocarbons. Moreover, the pellet catalyst exhibits a much better performance during an industry-relevant test, which suggests promising prospects for industrial applications.

  1. Counting and integrating microelectronics development for direct conversion X-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kraft, E.

    2008-02-15

    A novel signal processing concept for X-ray imaging with directly converting pixelated semiconductor sensors is presented. The novelty of this approach compared to existing concepts is the combination of charge integration and photon counting in every single pixel. Simultaneous operation of both signal processing chains extends the dynamic range beyond the limits of the individual schemes and allows determination of the mean photon energy. Medical applications such as X-ray computed tomography can benefit from this additional spectral information through improved contrast and the ability to determine the hardening of the tube spectrum due to attenuation by the scanned object. A prototype chip in 0.35-micrometer technology has been successfully tested. The pixel electronics are designed using a low-swing differential current mode logic. Key element is a configurable feedback circuit for the charge sensitive amplifier which provides continuous reset, leakage current compensation and replicates the input signal for the integrator. The thesis focusses on the electronic characterization of a second generation prototype chip and gives a detailed discussion of the circuit design. (orig.)

  2. Counting and integrating microelectronics development for direct conversion X-ray imaging

    International Nuclear Information System (INIS)

    Kraft, E.

    2008-02-01

    A novel signal processing concept for X-ray imaging with directly converting pixelated semiconductor sensors is presented. The novelty of this approach compared to existing concepts is the combination of charge integration and photon counting in every single pixel. Simultaneous operation of both signal processing chains extends the dynamic range beyond the limits of the individual schemes and allows determination of the mean photon energy. Medical applications such as X-ray computed tomography can benefit from this additional spectral information through improved contrast and the ability to determine the hardening of the tube spectrum due to attenuation by the scanned object. A prototype chip in 0.35-micrometer technology has been successfully tested. The pixel electronics are designed using a low-swing differential current mode logic. Key element is a configurable feedback circuit for the charge sensitive amplifier which provides continuous reset, leakage current compensation and replicates the input signal for the integrator. The thesis focusses on the electronic characterization of a second generation prototype chip and gives a detailed discussion of the circuit design. (orig.)

  3. High efficiency direct thermal to electric energy conversion from radioisotope decay using selective emitters and spectrally tuned solar cells

    Science.gov (United States)

    Chubb, Donald L.; Flood, Dennis J.; Lowe, Roland A.

    1993-01-01

    Thermophotovoltaic (TPV) systems are attractive possibilities for direct thermal-to-electric energy conversion, but have typically required the use of black body radiators operating at high temperatures. Recent advances in both the understanding and performance of solid rare-earth oxide selective emitters make possible the use of TPV at temperatures as low as 1200K. Both selective emitter and filter system TPV systems are feasible. However, requirements on the filter system are severe in order to attain high efficiency. A thin-film of a rare-earth oxide is one method for producing an efficient, rugged selective emitter. An efficiency of 0.14 and power density of 9.2 W/KG at 1200K is calculated for a hypothetical thin-film neodymia (Nd2O3) selective emitter TPV system that uses radioisotope decay as the thermal energy source.

  4. Systems definition space based power conversion systems: Executive summary

    Science.gov (United States)

    1977-01-01

    Potential space-located systems for the generation of electrical power for use on earth were investigated. These systems were of three basic types: (1) systems producing electrical power from solar energy; (2) systems producing electrical power from nuclear reactors; (3) systems for augmenting ground-based solar power plants by orbital sunlight reflectors. Configurations implementing these concepts were developed through an optimization process intended to yield the lowest cost for each. A complete program was developed for each concept, identifying required production rates, quantities of launches, required facilities, etc. Each program was costed in order to provide the electric power cost appropriate to each concept.

  5. Normal age-related conversion of bone marrow in the skull base. Assessment with MR imaging

    International Nuclear Information System (INIS)

    Kato, Koki; Tomura, Noriaki; Takahashi, Satoshi; Izumi, Junichi; Kurosawa, Ryo; Sashi, Ryuji; Watarai, Jiro

    2000-01-01

    The purpose of this study was to assess the normal age-related sequence of conversion from hematopoietic to fatty marrow in the skull base by means of MR imaging. We retrospectively reviewed T1-weighted MR images of the skull base for the distribution of hematopoietic and fatty marrow. The subjects consisted of 169 MR examinations that were performed with the spin-echo technique. The age of the subjects ranged from 0 months to 20 years old. Patients with known marrow abnormalities were excluded from this study. Marrow conversion was assessed in the presphenoid, postsphenoid, basiocciput, petrous apex, clivus, zygomatic bone, and condyle of the mandible. The signal intensity was visually graded, and the signal intensity ratio was determined on the basis of the intensities of the subcutaneous fat and air. The signal intensity of all observed regions was as low as that of muscles until 3 months of age. Conversion of hematopoietic to fatty marrow first occurred in the zygomatic bone until 6 months of age. The presphenoid increased in signal intensity from 5 months to 2 years of age, and the sphenoid sinus began to be pneumatic at this age. Marrow conversion of the postsphenoid and basiocciput was later than that of the presphenoid. Most of the bone marrow of the skull base appeared as fatty conversion until 3 years of age, although some mandibular condyles appeared hematopoietic at 3 years of age. The normal age-related conversion from hematopoietic to fatty marrow in the skull base followed a well-defined sequence. Knowledge of the normal bone marrow conversion by MR imaging is essential for the recognition of pathologic marrow processes. (author)

  6. Multifunctional switching unit for add/drop, wavelength conversion, format conversion, and WDM multicast based on bidirectional LCoS and SOA-loop architecture.

    Science.gov (United States)

    Wang, Danshi; Zhang, Min; Qin, Jun; Lu, Guo-Wei; Wang, Hongxiang; Huang, Shanguo

    2014-09-08

    We propose a multifunctional optical switching unit based on the bidirectional liquid crystal on silicon (LCoS) and semiconductor optical amplifier (SOA) architecture. Add/drop, wavelength conversion, format conversion, and WDM multicast are experimentally demonstrated. Due to the bidirectional characteristic, the LCoS device cannot only multiplex the input signals, but also de-multiplex the converted signals. Dual-channel wavelength conversion and format conversion from 2 × 25Gbps differential quadrature phase-shift-keying (DQPSK) to 2 × 12.5Gbps differential phase-shift-keying (DPSK) based on four-wave mixing (FWM) in SOA is obtained with only one pump. One-to-six WDM multicast of 25Gbps DQPSK signals with two pumps is also achieved. All of the multicast channels are with a power penalty less than 1.1 dB at FEC threshold of 3.8 × 10⁻³.

  7. Nuclear Propulsion through Direct Conversion of Fusion Energy: The Fusion Driven Rocket

    Science.gov (United States)

    Slough, John; Pancotti, Anthony; Kirtley, David; Pihl, Christopher; Pfaff, Michael

    2012-01-01

    The future of manned space exploration and development of space depends critically on the creation of a dramatically more proficient propulsion architecture for in-space transportation. A very persuasive reason for investigating the applicability of nuclear power in rockets is the vast energy density gain of nuclear fuel when compared to chemical combustion energy. Current nuclear fusion efforts have focused on the generation of electric grid power and are wholly inappropriate for space transportation as the application of a reactor based fusion-electric system creates a colossal mass and heat rejection problem for space application.

  8. An improved principal component analysis based region matching method for fringe direction estimation

    Science.gov (United States)

    He, A.; Quan, C.

    2018-04-01

    The principal component analysis (PCA) and region matching combined method is effective for fringe direction estimation. However, its mask construction algorithm for region matching fails in some circumstances, and the algorithm for conversion of orientation to direction in mask areas is computationally-heavy and non-optimized. We propose an improved PCA based region matching method for the fringe direction estimation, which includes an improved and robust mask construction scheme, and a fast and optimized orientation-direction conversion algorithm for the mask areas. Along with the estimated fringe direction map, filtered fringe pattern by automatic selective reconstruction modification and enhanced fast empirical mode decomposition (ASRm-EFEMD) is used for Hilbert spiral transform (HST) to demodulate the phase. Subsequently, windowed Fourier ridge (WFR) method is used for the refinement of the phase. The robustness and effectiveness of proposed method are demonstrated by both simulated and experimental fringe patterns.

  9. An XML based middleware for ECG format conversion.

    Science.gov (United States)

    Li, Xuchen; Vojisavljevic, Vuk; Fang, Qiang

    2009-01-01

    With the rapid development of information and communication technologies, various e-health solutions have been proposed. The digitized medical images as well as the mono-dimension medical signals are two major forms of medical information that are stored and manipulated within an electronic medical environment. Though a variety of industrial and international standards such as DICOM and HL7 have been proposed, many proprietary formats are still pervasively used by many Hospital Information System (HIS) and Picture Archiving and Communication System (PACS) vendors. Those proprietary formats are the big hurdle to form a nationwide or even worldwide e-health network. Thus there is an imperative need to solve the medical data integration problem. Moreover, many small clinics, many hospitals in developing countries and some regional hospitals in developed countries, which have limited budget, have been shunned from embracing the latest medical information technologies due to their high costs. In this paper, we propose an XML based middleware which acts as a translation engine to seamlessly integrate clinical ECG data from a variety of proprietary data formats. Furthermore, this ECG translation engine is designed in a way that it can be integrated into an existing PACS to provide a low cost medical information integration and storage solution.

  10. Format conversion between CAD data and GIS data based on ArcGIS

    Science.gov (United States)

    Xie, Qingqing; Wei, Bo; Zhang, Kailin; Wang, Zhichao

    2015-12-01

    To make full use of the data resources and realize a sharing for the different types of data in different industries, a method of format conversion between CAD data and GIS data based on ArcGIS was proposed. To keep the integrity of the converted data, some key steps to process CAD data before conversion were made in AutoCAD. For examples, deleting unnecessary elements such as title, border and legend avoided the appearance of unnecessary elements after conversion, as layering data again by a national standard avoided the different types of elements to appear in a same layer after conversion. In ArcGIS, converting CAD data to GIS data was executed by the correspondence of graphic element classification between AutoCAD and ArcGIS. In addition, an empty geographic database and feature set was required to create in ArcGIS for storing the text data of CAD data. The experimental results show that the proposed method avoids a large amount of editing work in data conversion and maintains the integrity of spatial data and attribute data between before and after conversion.

  11. Ultra-high-speed all-channel serial-to-parallel conversion based on complete optical fourier transformation

    DEFF Research Database (Denmark)

    Guan, Pengyu; Røge, Kasper Meldgaard; Morioka, Toshio

    2016-01-01

    We propose a serial-to-parallel conversion scheme based on complete OFT, allowing simultaneous conversion of all channels. We demonstrate all 32-channel simultaneous OTDM to WDM conversion of 320-Gbit/s DPSK and of 640-Gbit/s DQPSK signal, respectively....

  12. A randomized controlled clinical trial of a hypnosis-based treatment for patients with conversion disorder, motor type

    NARCIS (Netherlands)

    Moene, F.C.; Spinhoven, P.; Hoogduin, C.A.L.; Dyck, R. van

    2003-01-01

    This study tested whether a hypnosis-based intervention showed promise as a treatment for patients with conversion disorder, motor type. Forty-four outpatients with conversion disorder, motor type, or somatization disorder with motor conversion symptoms, were randomly assigned to a hypnosis or a

  13. Amorphous and Polycrystalline Photoconductors for Direct Conversion Flat Panel X-Ray Image Sensors

    Directory of Open Access Journals (Sweden)

    Karim S. Karim

    2011-05-01

    Full Text Available In the last ten to fifteen years there has been much research in using amorphous and polycrystalline semiconductors as x-ray photoconductors in various x-ray image sensor applications, most notably in flat panel x-ray imagers (FPXIs. We first outline the essential requirements for an ideal large area photoconductor for use in a FPXI, and discuss how some of the current amorphous and polycrystalline semiconductors fulfill these requirements. At present, only stabilized amorphous selenium (doped and alloyed a-Se has been commercialized, and FPXIs based on a-Se are particularly suitable for mammography, operating at the ideal limit of high detective quantum efficiency (DQE. Further, these FPXIs can also be used in real-time, and have already been used in such applications as tomosynthesis. We discuss some of the important attributes of amorphous and polycrystalline x-ray photoconductors such as their large area deposition ability, charge collection efficiency, x-ray sensitivity, DQE, modulation transfer function (MTF and the importance of the dark current. We show the importance of charge trapping in limiting not only the sensitivity but also the resolution of these detectors. Limitations on the maximum acceptable dark current and the corresponding charge collection efficiency jointly impose a practical constraint that many photoconductors fail to satisfy. We discuss the case of a-Se in which the dark current was brought down by three orders of magnitude by the use of special blocking layers to satisfy the dark current constraint. There are also a number of polycrystalline photoconductors, HgI2 and PbO being good examples, that show potential for commercialization in the same way that multilayer stabilized a-Se x-ray photoconductors were developed for commercial applications. We highlight the unique nature of avalanche multiplication in a-Se and how it has led to the development of the commercial HARP video-tube. An all solid state version of the

  14. A new method of waveform digitization based on time-interleaved A/D conversion

    International Nuclear Information System (INIS)

    Ye Chunfeng; Zhao Lei; Feng Changqing; Liu Shubin; An Qi

    2013-01-01

    Time interleaved analog-to-digital conversion (TIADC) based on parallelism is an effective way to meet the requirement of the ultra-fast waveform digitizer beyond Gsps. Different methods to correct the mismatch errors among different analog-to-digital conversion channels have been developed previously. To overcome the speed limitation in hardware design and to implement the mismatch correction algorithm in real time, this paper proposes a fully parallel correction algorithm. A 12-bit 1-Gsps waveform digitizer with ENOB around 10.5 bit from 5 MHz to 200 MHz is implemented based on the real-time correction algorithm. (authors)

  15. A frequency conversion mode for dispenser in the service station based on flow rate signal

    International Nuclear Information System (INIS)

    Liu, Y J; Tang, D; Huang, J B; Liu, J; Jia, P F

    2012-01-01

    Dispenser is an integrated fuel transport and measurement system at the service station. In this paper, we developed a frequency conversion mode for the dispenser, based on the flow rate signal which is obtained from the converter measuring flow capacity. After introducing the frequency conversion mode to dispenser, we obtained that pump rotates at a high speed when fuelled with high flow rate, and it rotates at a low speed when fuelled with low flow rate. This makes the fuel dispenser more energy-efficient and controllable. We also did some valve optimizations on the dispenser and developed a new control mode for preset refuelling based on the frequency conversion mode, Experimental and theoretical studies have shown that the new dispenser not only can meet the national standards, but also performs better than the ordinary one especially in preset refuelling.

  16. Off-axis holographic lens spectrum-splitting photovoltaic system for direct and diffuse solar energy conversion.

    Science.gov (United States)

    Vorndran, Shelby D; Chrysler, Benjamin; Wheelwright, Brian; Angel, Roger; Holman, Zachary; Kostuk, Raymond

    2016-09-20

    This paper describes a high-efficiency, spectrum-splitting photovoltaic module that uses an off-axis volume holographic lens to focus and disperse incident solar illumination to a rectangular shaped high-bandgap indium gallium phosphide cell surrounded by strips of silicon cells. The holographic lens design allows efficient collection of both direct and diffuse illumination to maximize energy yield. We modeled the volume diffraction characteristics using rigorous coupled-wave analysis, and simulated system performance using nonsequential ray tracing and PV cell data from the literature. Under AM 1.5 illumination conditions the simulated module obtained a 30.6% conversion efficiency. This efficiency is a 19.7% relative improvement compared to the more efficient cell in the system (silicon). The module was also simulated under a typical meteorological year of direct and diffuse irradiance in Tucson, Arizona, and Seattle, Washington. Compared to a flat panel silicon module, the holographic spectrum splitting module obtained a relative improvement in energy yield of 17.1% in Tucson and 14.0% in Seattle. An experimental proof-of-concept volume holographic lens was also fabricated in dichromated gelatin to verify the main characteristics of the system. The lens obtained an average first-order diffraction efficiency of 85.4% across the aperture at 532 nm.

  17. Food waste conversion options in Singapore: environmental impacts based on an LCA perspective.

    Science.gov (United States)

    Khoo, Hsien H; Lim, Teik Z; Tan, Reginald B H

    2010-02-15

    Proper management and recycling of huge volumes of food waste is one of the challenges faced by Singapore. Semakau island - the only offshore landfill of the nation - only accepts inert, inorganic solid waste and therefore a large bulk of food waste is directed to incinerators. A remaining small percent is sent for recycling via anaerobic digestion (AD), followed by composting of the digestate material. This article investigates the environmental performance of four food waste conversion scenarios - based on a life cycle assessment perspective - taking into account air emissions, useful energy from the incinerators and AD process, as well as carbon dioxide mitigation from the compost products derived from the digestate material and a proposed aerobic composting system. The life cycle impact results were generated for global warming, acidification, eutrophication, photochemical oxidation and energy use. The total normalized results showed that a small-scale proposed aerobic composting system is more environmentally favorable than incinerators, but less ideal compared to the AD process. By making full use of the AD's Recycling Phase II process alone, the Singapore Green Plan's 2012 aim to increase the recycling of food waste to 30% can easily be achieved, along with reduced global warming impacts.

  18. Using Critical Race Theory to Explore Race-Based Conversations through a Critical Family Book Club

    Science.gov (United States)

    Johnson, Lamar L.

    2016-01-01

    Stemming from my personal encounter with what I consider a racial affliction imposed by a White female teacher, I provide a glimpse of my racial narrative as a young Black male to illustrate a reference point for thinking through how racism functions in homes and schools. It touches on the importance of race-based conversations within school and…

  19. 5 CFR 315.712 - Conversion based on service as a Federal Career Intern.

    Science.gov (United States)

    2010-01-01

    ... Career Intern. 315.712 Section 315.712 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL... Employment From Other Types of Employment § 315.712 Conversion based on service as a Federal Career Intern... employment, a career intern who: (1) Has successfully completed a Federal Career Intern Program, under § 213...

  20. Conversations about Curriculum Change: Mathematical Thinking and Team-Based Learning in a Discrete Mathematics Course

    Science.gov (United States)

    Paterson, Judy; Sneddon, Jamie

    2011-01-01

    This article reports on the learning conversations between a mathematician and a mathematics educator as they worked together to change the delivery model of a third year discrete mathematics course from a traditional lecture mode to team-based learning (TBL). This change prompted the mathematician to create team tasks which increasingly focused…

  1. A Switched-Capacitor Based High Conversion Ratio Converter for Renewable Energy Applications

    DEFF Research Database (Denmark)

    Li, Kerui; Yin, Zhijian; Yang, Yongheng

    2017-01-01

    A high step-up switched-capacitor based converter is proposed in this paper. The proposed converter features high conversion ratio, low voltage stress and continuous input current, which makes it very suitable for renewable energy applications like photovoltaic systems. More importantly......, the proposed switched-capacitor cells in series with converter can be generalized in two ways, resulting in dc-dc converters of ultra-high dc conversion ratios. Theoretical analysis, simulation and experimental tests have demonstrated the superior performance of the proposed converter in terms of high dc...

  2. High-accuracy resolver-to-digital conversion via phase locked loop based on PID controller

    Science.gov (United States)

    Li, Yaoling; Wu, Zhong

    2018-03-01

    The problem of resolver-to-digital conversion (RDC) is transformed into the problem of angle tracking control, and a phase locked loop (PLL) method based on PID controller is proposed in this paper. This controller comprises a typical PI controller plus an incomplete differential which can avoid the amplification of higher-frequency noise components by filtering the phase detection error with a low-pass filter. Compared with conventional ones, the proposed PLL method makes the converter a system of type III and thus the conversion accuracy can be improved. Experimental results demonstrate the effectiveness of the proposed method.

  3. CORROSION BEHAVIOR OF A CONVERSION COATING BASED ON ZIRCONIUM AND COLORANTS ON GALVANIZED STEEL BY ELECTRODEPOSITION

    Directory of Open Access Journals (Sweden)

    Josiane Soares Costa

    2015-06-01

    Full Text Available Corrosion performance of Zr-based coating on substrates obtained by zinc electrodeposition in an alkaline bath is compared to chromate coatings (Cr III and Cr VI. The “nano Zr” is a conversion coating formed by immersion in a hexafluorozirconic acid solution. Since the “nano Zr” coating is transparent, the addiction of a colorant provides color to the surface. In this case, the colorant, when applied after the conversion coating, conferred the yellow color to the surface. The coating produced improves the corrosion protection of the substrate. For this study the samples were analyzed by electrochemical impedance spectroscopy (EIS and accelerated corrosion test in a humidity chamber. The results showed similar behaviors between the “nano Zr”, colorant and the chromate (Cr III coating. Therefore this kind of conversion coating is a promising substitute for chromate coatings.

  4. Wideband and High-Efficiency Reflective Polarization Conversion Metasurface Based on Anisotropic Metamaterials

    Science.gov (United States)

    Zheng, Qi; Guo, Chenjiang; Yuan, Pengliang; Ren, Yu-Hui; Ding, Jun

    2018-02-01

    In this paper, we propose a wideband and high-efficiency reflective polarization conversion metasurface (PCM) based on anisotropic metamaterials. The PCM has a period of sub-wavelength and simple design with a double-meander-line-shaped resonator printed on a metallic copper plate backed dielectric substrate. Owing to strong anisotropic properties and multiple plasmon resonances at neighboring frequencies, the PCM has a simulated fractional bandwidth of 82.3% from 8.40 GHz to 20.15 GHz with a polarization conversion ratio over 0.9. Numerical analysis and experimental validation are carried out to study the polarization conversion characteristics of the PCM. In addition, the mechanisms are analyzed in detail on the basis of multiple plasmon resonances and surface magnetic field distributions, respectively. The measured and simulated results obtained are in good agreement, which validates the effectiveness of the simulations and analysis.

  5. Study on Conversion Between Momentum and Contrarian Based on Fractal Game

    Science.gov (United States)

    Wu, Xu; Song, Guanghui; Deng, Yan; Xu, Lin

    2015-06-01

    Based on the fractal game which is performed by the majority and the minority, the fractal market theory (FMT) is employed to describe the features of investors' decision-making. Accordingly, the process of fractal games is formed in order to analyze the statistical features of conversion between momentum and contrarian. The result shows that among three fractal game mechanisms, the statistical feature of simulated return rate series is much more similar to log returns on actual series. In addition, the conversion between momentum and contrarian is also extremely similar to real situation, which can reflect the effectiveness of using fractal game in analyzing the conversion between momentum and contrarian. Moreover, it also provides decision-making reference which helps investors develop effective investment strategy.

  6. The caring relationship in hospice care: an analysis based on the ethics of the caring conversation.

    Science.gov (United States)

    Olthuis, Gert; Dekkers, Wim; Leget, Carlo; Vogelaar, Paul

    2006-01-01

    Good nursing is more than exercising a specific set of skills. It involves the personal identity of the nurse. The aim of this article is to answer two questions: (1) what kind of person should the hospice nurse be? and (2) how should the hospice nurse engage in caring conversations? To answer these questions we analyse a nurse's story that is intended to be a profile of an exemplary hospice nurse. This story was constructed from an analysis of five semistructured interviews with hospice nurses, based on the 'ethics of the caring conversation', which is inspired by the ethical perspective of Paul Ricoeur. The research questions concentrate on the norms of respect, responsibility and reciprocity, which are integral parts of the 'ethics of the caring conversation'.

  7. Activation of neural cell fate programs toward direct conversion of adult human fibroblasts into tri-potent neural progenitors using OCT-4.

    Science.gov (United States)

    Mitchell, Ryan R; Szabo, Eva; Benoit, Yannick D; Case, Daniel T; Mechael, Rami; Alamilla, Javier; Lee, Jong Hee; Fiebig-Comyn, Aline; Gillespie, Deda C; Bhatia, Mickie

    2014-08-15

    Several transcription factors and methods have been used to convert fibroblasts directly to neural fate and have provided insights into molecular mechanisms as to how each of these required factors orchestrate neural fate conversion. Here, we provide evidence and detailed characterization of the direct conversion process of primary adult human fibroblasts (hFib) to neural progenitor cells (NPC) using OCT4 alone. Factors previously associated with neural cell fate conversion were induced during hFib-NPC(OCT-4) generation, where OCT-4 alone was sufficient to induce neural fate conversion without the use of promiscuous small-molecule manipulation. Human Fib-NPC(OCT-4) proliferate, express neural stem/progenitor markers, and possess developmental potential that gives rise to all three major subtypes of neural cells: astrocytes, oligodendrocytes, and neurons with functional capacity. We propose a de-convoluted reprogramming approach for neural fate conversion in which OCT4 is sufficient for inducing neural conversion from hFib for disease modeling as well as the fundamental study of early neural fate induction.

  8. Overview of condition monitoring and operation control of electric power conversion systems in direct-drive wind turbines under faults

    Science.gov (United States)

    Huang, Shoudao; Wu, Xuan; Liu, Xiao; Gao, Jian; He, Yunze

    2017-09-01

    Electric power conversion system (EPCS), which consists of a generator and power converter, is one of the most important subsystems in a direct-drive wind turbine (DD-WT). However, this component accounts for the most failures (approximately 60% of the total number) in the entire DD-WT system according to statistical data. To improve the reliability of EPCSs and reduce the operation and maintenance cost of DD-WTs, numerous researchers have studied condition monitoring (CM) and fault diagnostics (FD). Numerous CM and FD techniques, which have respective advantages and disadvantages, have emerged. This paper provides an overview of the CM, FD, and operation control of EPCSs in DD-WTs under faults. After introducing the functional principle and structure of EPCS, this survey discusses the common failures in wind generators and power converters; briefly reviewed CM and FD methods and operation control of these generators and power converters under faults; and discussed the grid voltage faults related to EPCSs in DD-WTs. These theories and their related technical concepts are systematically discussed. Finally, predicted development trends are presented. The paper provides a valuable reference for developing service quality evaluation methods and fault operation control systems to achieve high-performance and high-intelligence DD-WTs.

  9. Materials and design concerning magnetohydrodynamic channels of direct power conversion from combustion gases thermal energy into electricity

    International Nuclear Information System (INIS)

    Yerouchalmi, David

    1970-01-01

    Direct power conversion of thermal energy into electricity by magnetohydrodynamic is defined through thermodynamic cycles of hot gases; the present work concerning only the channel-generator operating with fossil gases in open cycle. Insulating walls and electrodes are subject initially to general apparent working conditions and those are followed by several others which appear only when experimental stage is reached. First, a choice has to be made between cold walls and hot walls which have been both closely investigated. But experience and theory lead to a third solution: viz controlled temperature walls and to consequent thermal exchange design. Many additional phenomena such as: solid state electrolysis, vaporisation, corrosion and alkali seed migration are analysed; then some solutions are described, tried and suggested. Same is given for mechanical, cooling devices, cold electric junctions and current relays. Experimental devices and work done on several solutions are described and results given. New prospects are suggested; and, in conclusion, the subject still appears to merit quite an important amount of further research. (author) [fr

  10. Simulation on photoacoustic conversion efficiency of optical fiber-based ultrasound generator using different absorbing film materials

    Science.gov (United States)

    Sun, Kai; Wu, Nan; Tian, Ye; Wang, Xingwei

    2011-04-01

    The low energy-conversion efficiency in photoacoustic generation is the most critical hurdle preventing its wide applications. In recent studies, it was found that the selection of the energy-absorbing layer material and design of the acoustic generator structure both determine the photoacoustic conversion efficiency. The selection of the absorbing material is based on its optical, thermal, and mechanical properties. In this research, we calculated and compared the conversion efficiencies of six different absorbing film materials: bulk aluminum, bulk gold, graphite foil, graphite powder-resin mixture, gold nanospheres, and gold nanorods. The calculations were carried out by a finite element modeling (FEM) software, COMSOL Multiphysics. A 2D-axisymmetric model in COMSOL was built up to simulate a 3-layer structure: optical fiber tip, light absorbing film, and surrounding water. Three equations governed the thermo-elastic generation of ultrasonic waves: the heat conduction, thermal expansion and acoustic wave equations. In "thick-film" generation regime, majority of the laser energy is absorbed by the film and converted to high-frequency film vibration, and the vibration excites the ultrasound wave in the adjacent water, while the water would not be heated directly by the laser. From the results of this FEM simulation, the acoustic signal generated by gold nanosphere (or nanorod) film is over two times stronger than that generated by graphite powder-resin film of the same thickness. This simulation provides a strong support to the absorbing material selection for our proposed fiber ultrasound generator.

  11. Direct conversion of h-BN into c-BN and formation of epitaxial c-BN/diamond heterostructures

    International Nuclear Information System (INIS)

    Narayan, Jagdish; Bhaumik, Anagh; Xu, Weizong

    2016-01-01

    We have created a new state of BN (named Q-BN) through rapid melting and super undercooling and quenching by using nanosecond laser pulses. Phase pure c-BN is formed either by direct quenching of super undercooled liquid or by nucleation and growth from Q-BN. Thus, a direct conversion of hexagonal boron nitride (h-BN) into phase-pure cubic boron nitride (c-BN) is achieved by nanosecond pulsed laser melting at ambient temperatures and atmospheric pressure in air. According to the P-T phase diagram, the transformation from h-BN into c-BN under equilibrium processing can occur only at high temperatures and pressures, as the hBN-cBN-Liquid triple point is at 3500 K/9.5 GPa or 3700 K/7.0 GPa with a recent theoretical refinement. Using nonequilibrium nanosecond laser melting, we have created super undercooled state and shifted this triple point to as low as 2800 K and atmospheric pressure. The rapid quenching from super undercooled state leads to the formation of a new phase, named as Q-BN. We present detailed characterization of Q-BN and c-BN layers by using Raman spectroscopy, high-resolution scanning electron microscopy, electron-back-scatter diffraction, high-resolution TEM, and electron energy loss spectroscopy, and discuss the mechanism of formation of nanodots, nanoneedles, microneedles, and single-crystal c-BN on sapphire substrate. We have also deposited diamond by pulsed laser deposition of carbon on c-BN and created c-BN/diamond heterostructures, where c-BN acts as a template for epitaxial diamond growth. We discuss the mechanism of epitaxial c-BN and diamond growth on lattice matching c-BN template under pulsed laser evaporation of amorphous carbon, and the impact of this discovery on a variety of applications.

  12. Graphlet-based Characterization of Directed Networks

    Science.gov (United States)

    Sarajlić, Anida; Malod-Dognin, Noël; Yaveroğlu, Ömer Nebil; Pržulj, Nataša

    2016-10-01

    We are flooded with large-scale, dynamic, directed, networked data. Analyses requiring exact comparisons between networks are computationally intractable, so new methodologies are sought. To analyse directed networks, we extend graphlets (small induced sub-graphs) and their degrees to directed data. Using these directed graphlets, we generalise state-of-the-art network distance measures (RGF, GDDA and GCD) to directed networks and show their superiority for comparing directed networks. Also, we extend the canonical correlation analysis framework that enables uncovering the relationships between the wiring patterns around nodes in a directed network and their expert annotations. On directed World Trade Networks (WTNs), our methodology allows uncovering the core-broker-periphery structure of the WTN, predicting the economic attributes of a country, such as its gross domestic product, from its wiring patterns in the WTN for up-to ten years in the future. It does so by enabling us to track the dynamics of a country’s positioning in the WTN over years. On directed metabolic networks, our framework yields insights into preservation of enzyme function from the network wiring patterns rather than from sequence data. Overall, our methodology enables advanced analyses of directed networked data from any area of science, allowing domain-specific interpretation of a directed network’s topology.

  13. The utilisation of a career conversation framework based on Schein’s career anchors model

    Directory of Open Access Journals (Sweden)

    Magda Bezuidenhout

    2013-07-01

    Full Text Available Orientation: This  study  constituted  and  reported  on  the  outcomes  of  a  structured  career conversation  framework  based  on  Schein’s  eight  career  anchors  in  an  open  distance  and e-learning (ODeL university in South Africa. Research purpose: The purpose of the research was to report on the utilisation of a structured career conversation framework based on Schein’s career anchors model. Motivation for the study: The rationale for the study was the paucity of studies investigating career anchors in South Africa’s multicultural organisational context. Research design, approach and method: A quantitative approach was adopted in the study. The population consisted of 4200 employees at a university in South Africa. Statistical analysis was performed using one-way analysis of variance (ANOVA as well as a Scheffe post hoc test. Main  findings: The  findings  of  this  study  suggest  that  career  conversation  has  a  dynamic nature (i.e. it changes over a period of time. Consequently, career development interventions in the workplace need to approach the workforce holistically. Practical/managerial implications: The findings and results will assist managers, practitioners and  career  development  specialists  in  the  practical  implementation  of  the  career  anchor concept. Contribution/value-add: The career conversation framework based on Schein’s career anchors has expanded the existing theory to find the right balance between career conversations and career anchors to keep people motivated to perform optimally in an organisation.

  14. Energy-based modelling and control of wind energy conversion system with DFIG

    Science.gov (United States)

    Song, H. H.; Qu, Y. B.

    2011-02-01

    Focusing on wind energy conversion system (WECS) at the doubly-fed induction generator (DFIG) control level, a novel control approach was proposed to optimise wind energy capture from consideration of physical nature and energy relationship. According to energy flowing, the WECS was divided into several multi-ports energy conversion subsystems, and the structure matrices of the subsystems were elaborately designed. Based on this, port-controlled Hamiltonian models of the subsystems were obtained, and energy-based control using the models was provided to realise the machine side and the grid side control objectives of the WECS. The approach was applied on a 2 MW WECS, and compared with classical proportional-integral (PI) controller using MATLAB/Simulink. The results show that the energy-based control not only fully satisfies both side control requirements, but also has more robust control performances for a turbulent wind than the PI control.

  15. Potential pyrolysis pathway assessment for microalgae-based aviation fuel based on energy conversion efficiency and life cycle

    International Nuclear Information System (INIS)

    Guo, Fang; Wang, Xin; Yang, Xiaoyi

    2017-01-01

    Highlights: • High lipid content in microalgae increases energy conversion efficiency. • Indirect pathway has the highest mass ratio, energy ratio and energy efficiency. • The Isochrysis indirect pathway produces most kerosene component precursor. • The Isochrysis indirect pyrolysis pathway shows the best performance in LCA. - Abstract: Although the research of microalgae pyrolysis has been conducted for many years, there is a lack of investigations on energy efficiency and life cycle assessment. In this study, we investigated the biocrude yield and energy efficiency of direct pyrolysis, microalgae residue pyrolysis after lipid extraction (indirect pyrolysis), and different microalgae co-pyrolysis. This research also investigated the life cycle assessment of the three different pyrolysis pathways. A system boundary of Well-to-Wake (WTWa) was defined and included sub-process models, such as feedstock production, fuel production and pump-to-wheels (PTW) stages. The pathway of Isochrysis indirect pyrolysis shows the best performance in the mass ratio and energy ratio, produces the most kerosene component precursor, has the lowest WTWa total energy input, fossil fuel consumption and greenhouse gas emissions, and resultes in the best energy efficiency. All the evidence indicates that Isochrysis R2 pathway is a potential and optimal pyrolysis pathway to liquid biofuels. The mass ratio of pyrolysis biocrude is shown to be the decisive factor for different microalgae species. The sensitivity analysis results also indicates that the life cycle indicators are particularly sensitive to the mass ratio of pyrolysis biocrude for microalgae-based hydrotreated pyrolysis aviation fuel.

  16. Flicker noise comparison of direct conversion mixers using Schottky and HBT dioderings in SiGe:C BiCMOS technology

    DEFF Research Database (Denmark)

    Michaelsen, Rasmus Schandorph; Johansen, Tom Keinicke; Tamborg, Kjeld

    2015-01-01

    In this paper, we present flicker noise measurements of two X-band direct conversion mixers implemented in a SiGe:C BiCMOS technology. Both mixers use a ring structure with either Schottky diodes or diode-connected HBTs for double balanced operation. The mixers are packaged in a metal casing...

  17. Bit-rate-transparent optical RZ-to-NRZ format conversion based on linear spectral phase filtering

    DEFF Research Database (Denmark)

    Maram, Reza; Da Ros, Francesco; Guan, Pengyu

    2017-01-01

    We propose a novel and strikingly simple design for all-optical bit-rate-transparent RZ-to-NRZ conversion based on optical phase filtering. The proposed concept is experimentally validated through format conversion of a 640 Gbit/s coherent RZ signal to NRZ signal.......We propose a novel and strikingly simple design for all-optical bit-rate-transparent RZ-to-NRZ conversion based on optical phase filtering. The proposed concept is experimentally validated through format conversion of a 640 Gbit/s coherent RZ signal to NRZ signal....

  18. Solar-thermal conversion and thermal energy storage of graphene foam-based composites.

    Science.gov (United States)

    Zhang, Lianbin; Li, Renyuan; Tang, Bo; Wang, Peng

    2016-08-14

    Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a commonly used PCM, paraffin wax. The high macroporosity and low density of the graphene foam allow for high weight fraction of the PCM to be incorporated, which enhances the heat storage capacity of the composite. The interconnected graphene sheets in the composite provide (1) the solar-thermal conversion capability, (2) high thermal conductivity and (3) form stability of the composite. Under light irradiation, the composite effectively collects and converts the light energy into thermal energy, and the converted thermal energy is stored in the PCM and released in an elongated period of time for sustained utilization. This study provides a promising route for sustainable utilization of solar energy.

  19. Solar-thermal conversion and thermal energy storage of graphene foam-based composite

    KAUST Repository

    Zhang, Lianbin

    2016-07-11

    Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a commonly used PCM, paraffin wax. The high macroporosity and low density of the graphene foam allow for high weight fraction of the PCM to be incorporated, which enhances heat storage capacity of the composite. The interconnected graphene sheets in the composite provide (1) the solar-thermal conversion capability, (2) high thermal conductivity and (3) form stability of the composite. Under light irradiation, the composite effectively collects and converts the light energy into thermal energy, and the converted thermal energy is stored in the PCM and released in an elongated period of time for sustained utilization. This study provides a promising route for sustainable utilization of solar energy.

  20. Direct catalytic conversion of methane and light hydrocarbon gases. Final report, October 1, 1986--July 31, 1989

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, R.B. Jr.; Posin, B.M.; Chan, Yee-Wai

    1995-06-01

    This project explored conversion of methane to useful products by two techniques that do not involve oxidative coupling. The first approach was direct catalytic dehydrocoupling of methane to give hydrocarbons and hydrogen. The second approach was oxidation of methane to methanol by using heterogenized versions of catalysts that were developed as homogeneous models of cytochrome-P450, an enzyme that actively hydroxylates hydrocarbons by using molecular oxygen. Two possibilities exist for dehydrocoupling of methane to higher hydrocarbons: The first, oxidative coupling to ethane/ethylene and water, is the subject of intense current interest. Nonoxidative coupling to higher hydrocarbons and hydrogen is endothermic, but in the absence of coke formation the theoretical thermodynamic equilibrium yield of hydrocarbons varies from 25% at 827{degrees}C to 65% at 1100{degrees}C (at atmospheric pressure). In this project we synthesized novel, highly dispersed metal catalysts by attaching metal clusters to inorganic supports. The second approach mimics microbial metabolism of methane to produce methanol. The methane mono-oxygenase enzyme responsible for the oxidation of methane to methanol in biological systems has exceptional selectivity and very good rates. Enzyme mimics are systems that function as the enzymes do but overcome the problems of slow rates and poor stability. Most of that effort has focused on mimics of cytochrome P-450, which is a very active selective oxidation enzyme and has a metalloporphyrin at the active site. The interest in nonporphyrin mimics coincides with the interest in methane mono-oxygenase, whose active site has been identified as a {mu}-oxo dinuclear iron complex.We employed mimics of cytochrome P-450, heterogenized to provide additional stability. The oxidation of methane with molecular oxygen was investigated in a fixed-bed, down-flow reactor with various anchored metal phthalocyanines (PC) and porphyrins (TPP) as the catalysts.

  1. Conversion Reaction-Based Oxide Nanomaterials for Lithium Ion Battery Anodes.

    Science.gov (United States)

    Yu, Seung-Ho; Lee, Soo Hong; Lee, Dong Jun; Sung, Yung-Eun; Hyeon, Taeghwan

    2016-04-27

    Developing high-energy-density electrodes for lithium ion batteries (LIBs) is of primary importance to meet the challenges in electronics and automobile industries in the near future. Conversion reaction-based transition metal oxides are attractive candidates for LIB anodes because of their high theoretical capacities. This review summarizes recent advances on the development of nanostructured transition metal oxides for use in lithium ion battery anodes based on conversion reactions. The oxide materials covered in this review include oxides of iron, manganese, cobalt, copper, nickel, molybdenum, zinc, ruthenium, chromium, and tungsten, and mixed metal oxides. Various kinds of nanostructured materials including nanowires, nanosheets, hollow structures, porous structures, and oxide/carbon nanocomposites are discussed in terms of their LIB anode applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Efficient conversion from 1 to 2 microm by a KTP-based ring optical parametric oscillator.

    Science.gov (United States)

    Arisholm, G; Lippert, E; Rustad, G; Stenersen, K

    2002-08-01

    Conversion of Q -switched 1.064-microm Nd:YAG laser pulses to the 2-2.2-mu; m region with 46% efficiency is demonstrated with a KTP-based type 2 phase-matched optical parametric oscillator (OPO) with two pairs of walk-off compensating crystals in a ring resonator. With 10 mJ of pump energy, we obtain 2.5 mJ at the 2.06-microm signal and 2.1 mJ at the 2.2-microm idler, with a beam quality of M(2) approximately 1.4 . With a ZnGeP(2) -based OPO pumped by the signal from the KTP OPO we achieved 14% conversion efficiency from 1.064microm to the 3-5-microm range.

  3. A browser-based tool for conversion between Fortran NAMELIST and XML/HTML

    Science.gov (United States)

    Naito, O.

    A browser-based tool for conversion between Fortran NAMELIST and XML/HTML is presented. It runs on an HTML5 compliant browser and generates reusable XML files to aid interoperability. It also provides a graphical interface for editing and annotating variables in NAMELIST, hence serves as a primitive code documentation environment. Although the tool is not comprehensive, it could be viewed as a test bed for integrating legacy codes into modern systems.

  4. A browser-based tool for conversion between Fortran NAMELIST and XML/HTML

    Directory of Open Access Journals (Sweden)

    O. Naito

    2017-01-01

    Full Text Available A browser-based tool for conversion between Fortran NAMELIST and XML/HTML is presented. It runs on an HTML5 compliant browser and generates reusable XML files to aid interoperability. It also provides a graphical interface for editing and annotating variables in NAMELIST, hence serves as a primitive code documentation environment. Although the tool is not comprehensive, it could be viewed as a test bed for integrating legacy codes into modern systems.

  5. A current controlled matrix converter for wind energy conversion systems based on permanent magnet synchronous generator

    OpenAIRE

    Naggar H. Saad; Ahmed A. El-Sattar; Mohamed I. Marei

    2016-01-01

    The main challenges of wind energy conversion systems (WECS) are to maximize the energy capture from the wind and injecting reactive power during the fault. This paper presents a current controlled matrix converter to interface Permanent Magnet Synchronous Generators (PMSG) based WECS with the grid. To achieve fast dynamic response with reduced current ripples, a hysteresis current control is utilized. The proposed control system decouples the active and reactive components of the PMSG curren...

  6. Direct Energy Conversion Fission Reactor, Gaseous Core Reactor with Magnetohydrodynamic (MHD) Generator; Final Report - Part I and Part II

    Energy Technology Data Exchange (ETDEWEB)

    Samim Anghaie; Blair Smith; Travis Knight

    2002-11-12

    This report focuses on the power conversion cycle and efficiency. The technical issues involving the ionization mechanisms, the power management and distribution and radiation shielding and safety will be discussed in future reports.

  7. Direct conversion of cellulose using carbon monoxide and water on a Pt-Mo2C/C catalyst

    KAUST Repository

    Li, Jing

    2014-01-01

    CO and H2O were employed as the hydrogen source for cellulose conversion to polyols. Pt-Mo2C/C tandem catalyst with the Pt-Mo 2C domain responsible for H2 and/or H production and the Pt-C domain for cellulose conversion was fabricated. Considerable polyols were obtained over this tandem Pt-Mo2C/C catalyst. This journal is © 2014 The Royal Society of Chemistry.

  8. The Role of Conversation Policy in Carrying Out Agent Conversations

    International Nuclear Information System (INIS)

    Link, Hamilton E.; Phillips, Laurence R.

    1999-01-01

    Structured conversation diagrams, or conversation specifications, allow agents to have predictable interactions and achieve predefined information-based goals, but they lack the flexibility needed to function robustly in an unpredictable environment. We propose a mechanism that combines a typical conversation structure with a separately established policy to generate an actual conversation. The word ''policy'' connotes a high-level direction external to a specific planned interaction with the environment. Policies, which describe acceptable procedures and influence decisions, can be applied to broad sets of activity. Based on their observation of issues related to a policy, agents may dynamically adjust their communication patterns. The policy object describes limitations, constraints, and requirements that may affect the conversation in certain circumstances. Using this new mechanism of interaction simplifies the description of individual conversations and allows domain-specific issues to be brought to bear more easily during agent communication. By following the behavior of the conversation specification when possible and deferring to the policy to derive behavior in exceptional circumstances, an agent is able to function predictably under normal situations and still act rationally in abnormal situations. Different conversation policies applied to a given conversation specification can change the nature of the interaction without changing the specification

  9. The use of gas based energy conversion cycles for sodium fast reactors

    International Nuclear Information System (INIS)

    Saez, M.; Haubensack, D.; Alpy, N.; Gerber, A.; Daid, F.

    2008-01-01

    In the frame of Sodium Fast Reactors, CEA, AREVA and EDF are involved in a substantial effort providing both significant expertise and original work in order to investigate the interest to use a gas based energy conversion cycle as an alternative to the classical steam cycle. These gas cycles consist in different versions of the Brayton cycle, various types of gas being considered (helium, nitrogen, argon, separately or mixed, sub or supercritical carbon dioxide) as well as various cycle arrangements (indirect, indirect / combined cycles). The interest of such cycles is analysed in details by thermodynamic calculations and cycle optimisations. The objective of this paper is to provide a comparison between gas based energy conversion cycles from the viewpoint of the overall plant efficiency. Key factors affecting the Brayton cycle efficiency include the turbine inlet temperature, compressors and turbine efficiencies, recuperator effectiveness and cycle pressure losses. A nitrogen Brayton cycle at high pressure (between 100 and 180 bar) could appear as a potential near-term solution of classical gas power conversion system for maximizing the plant efficiency. At long-term, supercritical carbon dioxide Brayton cycle appears very promising for Sodium Fast Reactors, with a potential of high efficiency using even at a core outlet temperature of 545 deg. C. (authors)

  10. Robust Sliding Mode Control of Permanent Magnet Synchronous Generator-Based Wind Energy Conversion Systems

    Directory of Open Access Journals (Sweden)

    Guangping Zhuo

    2016-12-01

    Full Text Available The subject of this paper pertains to sliding mode control and its application in nonlinear electrical power systems as seen in wind energy conversion systems. Due to the robustness in dealing with unmodeled system dynamics, sliding mode control has been widely used in electrical power system applications. This paper presents first and high order sliding mode control schemes for permanent magnet synchronous generator-based wind energy conversion systems. The application of these methods for control using dynamic models of the d-axis and q-axis currents, as well as those of the high speed shaft rotational speed show a high level of efficiency in power extraction from a varying wind resource. Computer simulation results have shown the efficacy of the proposed sliding mode control approaches.

  11. Lanthanide based conversion coatings for long term wet storage of aluminium-clad spent fuel

    International Nuclear Information System (INIS)

    Fernandes, S.M.C.; Correa, O.V.; De Souza, J.A.; Ramanathan, L.V.

    2010-01-01

    Spent fuels from research reactors are stored in basins with water of less than desirable quality at many facilities around the world and instances of cladding failure caused by pitting corrosion have been reported. Conversion coatings have been used in many industries to protect different metals, including aluminium alloys. This paper presents the results of an ongoing investigation in which the corrosion resistance of lanthanide (cerium, lanthanum and praseodymium) based conversion coated RR fuel cladding alloys has been studied. Electrochemical tests in the laboratory revealed higher corrosion resistance of CeO 2 , La 2 O 3 and Pr 2 O 3 coated AA 1100 and AA 6061 alloys in NaCl solutions. Uncoated and CeO 2 coated coupons of these alloys exposed for 50 days to the spent fuel basin of the IEA-R1 research reactor in IPEN, Brazil, revealed marked reductions in the extent of pitting corrosion. (author)

  12. An experimentally validated model for geometrically nonlinear plucking-based frequency up-conversion in energy harvesting

    Science.gov (United States)

    Kathpalia, B.; Tan, D.; Stern, I.; Erturk, A.

    2018-01-01

    It is well known that plucking-based frequency up-conversion can enhance the power output in piezoelectric energy harvesting by enabling cyclic free vibration at the fundamental bending mode of the harvester even for very low excitation frequencies. In this work, we present a geometrically nonlinear plucking-based framework for frequency up-conversion in piezoelectric energy harvesting under quasistatic excitations associated with low-frequency stimuli such as walking and similar rigid body motions. Axial shortening of the plectrum is essential to enable plucking excitation, which requires a nonlinear framework relating the plectrum parameters (e.g. overlap length between the plectrum and harvester) to the overall electrical power output. Von Kármán-type geometrically nonlinear deformation of the flexible plectrum cantilever is employed to relate the overlap length between the flexible (nonlinear) plectrum and the stiff (linear) harvester to the transverse quasistatic tip displacement of the plectrum, and thereby the tip load on the linear harvester in each plucking cycle. By combining the nonlinear plectrum mechanics and linear harvester dynamics with two-way electromechanical coupling, the electrical power output is obtained directly in terms of the overlap length. Experimental case studies and validations are presented for various overlap lengths and a set of electrical load resistance values. Further analysis results are reported regarding the combined effects of plectrum thickness and overlap length on the plucking force and harvested power output. The experimentally validated nonlinear plectrum-linear harvester framework proposed herein can be employed to design and optimize frequency up-conversion by properly choosing the plectrum parameters (geometry, material, overlap length, etc) as well as the harvester parameters.

  13. Biomass thermochemical conversion program: 1987 annual report

    Energy Technology Data Exchange (ETDEWEB)

    Schiefelbein, G.F.; Stevens, D.J.; Gerber, M.A.

    1988-01-01

    The objective of the Biomass Thermochemical Conversion Program is to generate a base of scientific data and conversion process information that will lead to establishment of cost-effective processes for conversion of biomass resources into clean fuels. To accomplish this objective, in fiscal year 1987 the Thermochemical Conversion Program sponsored research activities in the following four areas: Liquid Hydrocarbon Fuels Technology; Gasification Technology; Direct Combustion Technology; Program Support Activities. In this report an overview of the Thermochemical Conversion Program is presented. Specific research projects are then described. Major accomplishments for 1987 are summarized.

  14. Conversion of a DWDM signal to a single Nyquist channel based on a complete optical Fourier transformation

    DEFF Research Database (Denmark)

    Guan, Pengyu; Røge, Kasper Meldgaard; Mulvad, Hans Christian Hansen

    2014-01-01

    We propose a DWDM-to-Nyquist channel conversion scheme based on complete Optical Fourier Transformation and optical Nyquist filtering. We demonstrate conversion from 50-GHz-grid 16×10 Gbit/s DPSK DWDM to a 160-Gbit/s Nyquist channel (0.9 symbol/s/Hz spectral efficiency) with 1.4 dB power penalty....

  15. A Parameter-based Model for Generating Culturally Adaptive Nonverbal Behaviors in Embodied Conversational Agents

    DEFF Research Database (Denmark)

    Lipi, Afia Akhter; Nakano, Yukiko; Rehm, Matthias

    2009-01-01

    The goal of this paper is to integrate culture as a computational term in embodied conversational agents by employing an empirical data-driven approach as well as a theoretical model-driven approach. We propose a parameter-based model that predicts nonverbal expressions appropriate for specific...... cultures. First, we introduce the Hofstede theory to describe socio-cultural characteristics of each country. Then, based on the previous studies in cultural differences of nonverbal behaviors, we propose expressive parameters to characterize nonverbal behaviors. Finally, by integrating socio...

  16. The utilisation of a career conversation framework based on Schein’s career anchors model

    Directory of Open Access Journals (Sweden)

    Magda Bezuidenhout

    2013-01-01

    Full Text Available Orientation: This  study  constituted  and  reported  on  the  outcomes  of  a  structured  career conversation  framework  based  on  Schein’s  eight  career  anchors  in  an  open  distance  and e-learning (ODeL university in South Africa.Research purpose: The purpose of the research was to report on the utilisation of a structured career conversation framework based on Schein’s career anchors model.Motivation for the study: The rationale for the study was the paucity of studies investigating career anchors in South Africa’s multicultural organisational context.Research design, approach and method: A quantitative approach was adopted in the study. The population consisted of 4200 employees at a university in South Africa. Statistical analysis was performed using one-way analysis of variance (ANOVA as well as a Scheffe post hoc test.Main  findings: The  findings  of  this  study  suggest  that  career  conversation  has  a  dynamic nature (i.e. it changes over a period of time. Consequently, career development interventions in the workplace need to approach the workforce holistically.Practical/managerial implications: The findings and results will assist managers, practitioners and  career  development  specialists  in  the  practical  implementation  of  the  career  anchor concept.Contribution/value-add: The career conversation framework based on Schein’s career anchors has expanded the existing theory to find the right balance between career conversations and career anchors to keep people motivated to perform optimally in an organisation.

  17. Gene array analysis of neural crest cells identifies transcription factors necessary for direct conversion of embryonic fibroblasts into neural crest cells

    Directory of Open Access Journals (Sweden)

    Tsutomu Motohashi

    2016-03-01

    Full Text Available Neural crest cells (NC cells are multipotent cells that emerge from the edge of the neural folds and migrate throughout the developing embryo. Although the gene regulatory network for generation of NC cells has been elucidated in detail, it has not been revealed which of the factors in the network are pivotal to directing NC identity. In this study we analyzed the gene expression profile of a pure NC subpopulation isolated from Sox10-IRES-Venus mice and investigated whether these genes played a key role in the direct conversion of Sox10-IRES-Venus mouse embryonic fibroblasts (MEFs into NC cells. The comparative molecular profiles of NC cells and neural tube cells in 9.5-day embryos revealed genes including transcription factors selectively expressed in developing trunk NC cells. Among 25 NC cell-specific transcription factor genes tested, SOX10 and SOX9 were capable of converting MEFs into SOX10-positive (SOX10+ cells. The SOX10+ cells were then shown to differentiate into neurons, glial cells, smooth muscle cells, adipocytes and osteoblasts. These SOX10+ cells also showed limited self-renewal ability, suggesting that SOX10 and SOX9 directly converted MEFs into NC cells. Conversely, the remaining transcription factors, including well-known NC cell specifiers, were unable to convert MEFs into SOX10+ NC cells. These results suggest that SOX10 and SOX9 are the key factors necessary for the direct conversion of MEFs into NC cells.

  18. Salt Stability - The Effect of pHmax on Salt to Free Base Conversion.

    Science.gov (United States)

    Hsieh, Yi-Ling; Merritt, Jeremy M; Yu, Weili; Taylor, Lynne S

    2015-09-01

    The aim of this study was to investigate how the disproportionation process can be impacted by the properties of the salt, specifically pHmax. Five miconazole salts and four sertraline salts were selected for this study. The extent of conversion was quantified using Raman spectroscopy. A mathematical model was utilized to estimate the theoretical amount of conversion. A trend was observed that for a given series of salts of a particular basic compound (both sertraline and miconazole are bases), the extent of disproportionation increases as pHmax decreases. Miconazole phosphate monohydrate and sertraline mesylate, although exhibiting significantly different pHmax values (more than 2 units apart), underwent a similar extent of disproportionation, which may be attributed to the lower buffering capacity of sertraline salts. This work shows that the disproportionation tendency can be influenced by pHmax and buffering capacity and thus highlights the importance of selecting the appropriate salt form during the screening process in order to avoid salt-to-free form conversion.

  19. Characterization and cysteine sensing performance of nanocomposites based on up-conversion excitation host and rhodamine-derived probes

    Science.gov (United States)

    Yuqing, Zhao; Yi, Xing; Lihua, Li; Juanjuan, Ma

    2018-02-01

    Optical sensing for cysteine (Cys) recognition is an interesting topic due to Cys biological participation. In this paper, two rhodamine-based chemosensors were designed for Cys optical sensing. For chemosensor photostability improvement, up-conversion nanocrystals were synthesized and used as excitation host. These nanocrystals were modified with a phase transfer reagent α-cyclodextrin (α-CD) to improve their compatibility with chemosensors. An efficient energy transfer from these nanocrystals to chemosensors under 980 nm radiation was observed and confirmed by spectral match analysis, energy transfer radius calculation and emission decay lifetime comparison. A direct bonding mechanism between Cys and chemosensors with bonding stoichiometry of 1:1 was established by Job's plot experiment. Given the presence of Cys, chemosensor emission was increased, showing emission turn on effect. These two chemosensors showed good selectivity, improved photostability and linear sensing response towards Cys.

  20. Clinical evaluation of digital angiographic system equipped with the Safire' flat-panel detector of a direct conversion type

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Yoshiaki; Miura, Yusuke; Goto, Keiichi [Shimadzu Corporation, Medical Systems Division, Research and Development, Kyoto (JP)] [and others

    2003-06-01

    This report presents a report on clinical evaluation of our newly developed flat-panel X-ray detector of a direct conversion type, designed to provide images of a resolution higher than, or at least equal to, that ensured by X-ray photographic films, in clinical digital X-ray cinematography. This new detector was named 'Safire' the acronym of 'Shimadzu advanced flat imaging receptor', emphasizing its high technological level, such as the capability to ensure high quality of images. The clinical evaluation of Shimadzu DIGITEX Premier digital angiography system, equipped with this new flat-panel X-ray detector of a direct conversion type, has been started in March, 2003, at the Kokura Memorial Hospital in Kyushu, Japan. (author)

  1. Silicon Based Direct Methanol Fuel Cells

    DEFF Research Database (Denmark)

    Larsen, Jackie Vincent

    The purpose of this project has been to investigate and fabricate small scale Micro Direct Methanol Fuel Cells (μDMFC). They are investigated as a possible alternative for Zinc-air batteries in small size consumer devices such as hearing aids. In such devices the conventional rechargeable batteri...... variation in the path length through the proton conductive phase. In addition the trade-off between mass transfer losses and activation losses deriving from the catalyst layer density is developed.......The purpose of this project has been to investigate and fabricate small scale Micro Direct Methanol Fuel Cells (μDMFC). They are investigated as a possible alternative for Zinc-air batteries in small size consumer devices such as hearing aids. In such devices the conventional rechargeable batteries...... on a perforated silicon plate which acts as a mechanical support structure a proton conducting polymer membrane, which connects catalyst layers deposited through spray coating on either side of the silicon device. An improvement of this design is also presented which integrates the catalyst layer into the current...

  2. Quaternion-Based Conversion Formulas for Kinematic Attitude of Floating Offshore Wind Turbines (FOWT)

    Science.gov (United States)

    Li, Yugang; Fu, Gaoyong

    2018-01-01

    A floater allowing large-angle motion supporting a large payload (wind turbine and nacelle) with large aerodynamic loads high above the water surface is a great challenge because of the raised center of gravity and large overturning moment. In this paper, the conversion formulas between Euler angles and quaternions were derived, the research offered an efficient methodology without singularity to compute large-angle rigid body rotations of a FOWT, which laid the foundation for quaternion-based attitude kinematic model introduced to describe the dynamic response of the FOWT system and further solution.

  3. Classifying head movements in video-recorded conversations based on movement velocity, acceleration and jerk

    DEFF Research Database (Denmark)

    Jongejan, Bart; Paggio, Patrizia; Navarretta, Costanza

    2017-01-01

    This paper is about the automatic annotation of head movements in videos of face-to-face conversations. Manual annotation of gestures is resource consuming, and modelling gesture behaviours in different types of communicative settings requires many types of annotated data. Therefore, developing...... methods for automatic annotation is crucial. We present an approach where an SVM classifier learns to classify head movements based on measurements of velocity, acceleration, and the third derivative of position with respect to time, jerk. Consequently, annotations of head movements are added to new video...

  4. Concept maps: A tool for knowledge management and synthesis in web-based conversational learning.

    Science.gov (United States)

    Joshi, Ankur; Singh, Satendra; Jaswal, Shivani; Badyal, Dinesh Kumar; Singh, Tejinder

    2016-01-01

    Web-based conversational learning provides an opportunity for shared knowledge base creation through collaboration and collective wisdom extraction. Usually, the amount of generated information in such forums is very huge, multidimensional (in alignment with the desirable preconditions for constructivist knowledge creation), and sometimes, the nature of expected new information may not be anticipated in advance. Thus, concept maps (crafted from constructed data) as "process summary" tools may be a solution to improve critical thinking and learning by making connections between the facts or knowledge shared by the participants during online discussion This exploratory paper begins with the description of this innovation tried on a web-based interacting platform (email list management software), FAIMER-Listserv, and generated qualitative evidence through peer-feedback. This process description is further supported by a theoretical construct which shows how social constructivism (inclusive of autonomy and complexity) affects the conversational learning. The paper rationalizes the use of concept map as mid-summary tool for extracting information and further sense making out of this apparent intricacy.

  5. Three-dimensional micro-printing of temperature sensors based on up-conversion luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Wickberg, Andreas; Mueller, Jonathan B. [Institute of Applied Physics and DFG-Center for Functional Nanostructures, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Mange, Yatin J.; Nann, Thomas [Ian Wark Research Institute, University of South Australia, Mawson Lakes Blvd, Adelaide, SA 5095 (Australia); Fischer, Joachim [Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Wegener, Martin [Institute of Applied Physics and DFG-Center for Functional Nanostructures, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany)

    2015-03-30

    The pronounced temperature dependence of up-conversion luminescence from nanoparticles doped with rare-earth elements enables local temperature measurements. By mixing these nanoparticles into a commercially available photoresist containing the low-fluorescence photo-initiator Irgacure 369, and by using three-dimensional direct laser writing, we show that micrometer sized local temperature sensors can be positioned lithographically as desired. Positioning is possible in pre-structured environments, e.g., within buried microfluidic channels or on optical or electronic chips. We use the latter as an example and demonstrate the measurement for both free space and waveguide-coupled excitation and detection. For the free space setting, we achieve a temperature standard deviation of 0.5 K at a time resolution of 1 s.

  6. Three-dimensional micro-printing of temperature sensors based on up-conversion luminescence

    International Nuclear Information System (INIS)

    Wickberg, Andreas; Mueller, Jonathan B.; Mange, Yatin J.; Nann, Thomas; Fischer, Joachim; Wegener, Martin

    2015-01-01

    The pronounced temperature dependence of up-conversion luminescence from nanoparticles doped with rare-earth elements enables local temperature measurements. By mixing these nanoparticles into a commercially available photoresist containing the low-fluorescence photo-initiator Irgacure 369, and by using three-dimensional direct laser writing, we show that micrometer sized local temperature sensors can be positioned lithographically as desired. Positioning is possible in pre-structured environments, e.g., within buried microfluidic channels or on optical or electronic chips. We use the latter as an example and demonstrate the measurement for both free space and waveguide-coupled excitation and detection. For the free space setting, we achieve a temperature standard deviation of 0.5 K at a time resolution of 1 s

  7. Conversion of lignocellulosic agave residues into liquid biofuels using an AFEX™-based biorefinery.

    Science.gov (United States)

    Flores-Gómez, Carlos A; Escamilla Silva, Eleazar M; Zhong, Cheng; Dale, Bruce E; da Costa Sousa, Leonardo; Balan, Venkatesh

    2018-01-01

    Agave-based alcoholic beverage companies generate thousands of tons of solid residues per year in Mexico. These agave residues might be used for biofuel production due to their abundance and favorable sustainability characteristics. In this work, agave leaf and bagasse residues from species Agave tequilana and Agave salmiana were subjected to pretreatment using the ammonia fiber expansion (AFEX) process. The pretreatment conditions were optimized using a response surface design methodology. We also identified commercial enzyme mixtures that maximize sugar yields for AFEX-pretreated agave bagasse and leaf matter, at ~ 6% glucan (w/w) loading enzymatic hydrolysis. Finally, the pretreated agave hydrolysates (at a total solids loading of ~ 20%) were used for ethanol fermentation using the glucose- and xylose-consuming strain Saccharomyces cerevisiae 424A (LNH-ST), to determine ethanol yields at industrially relevant conditions. Low-severity AFEX pretreatment conditions are required (100-120 °C) to enable efficient enzymatic deconstruction of the agave cell wall. These studies showed that AFEX-pretreated A. tequilana bagasse, A. tequilana leaf fiber, and A. salmiana bagasse gave ~ 85% sugar conversion during enzyme hydrolysis and over 90% metabolic yields of ethanol during fermentation without any washing step or nutrient supplementation. On the other hand, although lignocellulosic A. salmiana leaf gave high sugar conversions, the hydrolysate could not be fermented at high solids loadings, apparently due to the presence of natural inhibitory compounds. These results show that AFEX-pretreated agave residues can be effectively hydrolyzed at high solids loading using an optimized commercial enzyme cocktail (at 25 mg protein/g glucan) producing > 85% sugar conversions and over 40 g/L bioethanol titers. These results show that AFEX technology has considerable potential to convert lignocellulosic agave residues to bio-based fuels and chemicals in a biorefinery.

  8. Adhesion and corrosion studies of a lithium based conversion coating film on the 2024 aluminum alloy

    International Nuclear Information System (INIS)

    Castro, M.R.S.; Nogueira, J.C.; Thim, G.P.; Oliveira, M.A.S.

    2004-01-01

    AA2024-T3-aluminum alloy surfaces were coated using non-chromate and chromate conversion coatings. All coatings were painted with the 10P4-2-primer epoxy resin. Independent on the film formation process, films passed on the substrate/conversion coating wet tape adhesion test. However, only the chromate conversion coating passed on the conversion coating/primer epoxy resin adhesion test. Electrochemical corrosion measurements showed that non-chromate conversion coated surfaces present lower corrosion current density, bigger polarization resistance and less negative corrosion potential than chromate conversion coated surfaces

  9. Sensorless Control for the EVT-Based New Dual Power Flow Wind Energy Conversion System

    Directory of Open Access Journals (Sweden)

    Ying Zhu

    2017-06-01

    Full Text Available The dual power flow wind energy conversion system (DPF-WECS is a novel system which is based on the electrical variable transmission (EVT machine. The proposed sensorless control for the DPF-WECS is based on the model reference adaptive system (MRAS observer by combining the sliding mode (SM theory. The SM-MRAS observer is on account of the calculations without the requirement of the proportional-integral (PI loop which exists in the classical MRAS observer. Firstly, the sensorless algorithm is applied in the maximum power point tracking (MPPT control considering the torque loss for the outer rotor of the EVT. Secondly, the sensorless control is adopted for the inner rotor control of the EVT machine. The proposed sensorless control method based on the SM-MRAS for the DPF-WECS is verified by the simulation and experimental results.

  10. Assessment of control strategies for fault ride through of SCIG-based wind energy conversion systems

    Directory of Open Access Journals (Sweden)

    Manaullah

    2016-01-01

    Full Text Available With increasing penetration of wind energy into the power grid, researchers have started focusing more on control and coordination of wind energy conversion systems (WECS with the other components at system level, especially during fault. It is important to implement a suitable fault ride through control strategy to avoid tripping of the generators when the power system is subjected to voltage dips normally below 90% of nominal voltage. The dips below 90% may lead to a significant loss of generation and frequency collapse, followed by a blackout. This article implements and assesses the methodologies to deal with such situations for squirrel cage induction generator-based wind energy conversion systems employing fully rated power electronic converters. Three distinct control techniques—namely, balanced positive sequence control, positive negative sequence control, and dual current control—have been simulated and applied to grid side converter of SCIG-based WECS. The performance of all the three control strategies has been compared and presented in this work. During this study, the system is subjected to the most common unsymmetrical line to ground (LG fault and most severe symmetrical LLL fault on grid for the purpose of anaysis.

  11. Efficacy of melody-based aphasia therapy may strongly depend on rhythm and conversational speech formulas

    Directory of Open Access Journals (Sweden)

    Benjamin Stahl

    2014-04-01

    Full Text Available Left-hemisphere stroke patients suffering from language and speech disorders are often able to sing entire pieces of text fluently. This finding has inspired a number of melody-based rehabilitation programs – most notable among them a treatment known as Melodic Intonation Therapy – as well as two fundamental research questions. When the experimental design focuses on one point in time (cross section, one may determine whether or not singing has an immediate effect on syllable production in patients with language and speech disorders. When the design focuses on changes over several points in time (longitudinal section, one may gain insight as to whether or not singing has a long-term effect on language and speech recovery. The current work addresses both of these questions with two separate experiments that investigate the interplay of melody, rhythm and lyric type in 32 patients with non-fluent aphasia and apraxia of speech (Stahl et al., 2011; Stahl et al., 2013. Taken together, the experiments deliver three main results. First, singing and rhythmic pacing proved to be equally effective in facilitating immediate syllable production and long-term language and speech recovery. Controlling for various influences such as prosody, syllable duration and phonetic complexity, the data did not reveal any advantage of singing over rhythmic speech. This result was independent of lesion size and lesion location in the patients. Second, patients with extensive left-sided basal ganglia lesions produced more correct syllables when their speech was paced by rhythmic drumbeats. This observation is consistent with the idea that regular auditory cues may partially compensate for corticostriatal damage and thereby improve speech-motor planning (Grahn & Watson, 2013. Third, conversational speech formulas and well-known song lyrics yielded higher rates of correct syllable production than novel word sequences – whether patients were singing or speaking

  12. Relaxed damage threshold intensity conditions and nonlinear increase in the conversion efficiency of an optical parametric oscillator using a bi-directional pump geometry.

    Science.gov (United States)

    Norris, G; McConnell, G

    2010-03-01

    A novel bi-directional pump geometry that nonlinearly increases the nonlinear optical conversion efficiency of a synchronously pumped optical parametric oscillator (OPO) is reported. This bi-directional pumping method synchronizes the circulating signal pulse with two counter-propagating pump pulses within a linear OPO resonator. Through this pump scheme, an increase in nonlinear optical conversion efficiency of 22% was achieved at the signal wavelength, corresponding to a 95% overall increase in average power. Given an almost unchanged measured pulse duration of 260 fs under optimal performance conditions, this related to a signal wavelength peak power output of 18.8 kW, compared with 10 kW using the traditional single-pass geometry. In this study, a total effective peak intensity pump-field of 7.11 GW/cm(2) (corresponding to 3.55 GW/cm(2) from each pump beam) was applied to a 3 mm long periodically poled lithium niobate crystal, which had a damage threshold intensity of 4 GW/cm(2), without impairing crystal integrity. We therefore prove the application of this novel pump geometry provides opportunities for power-scaling of synchronously pumped OPO systems together with enhanced nonlinear conversion efficiency through relaxed damage threshold intensity conditions.

  13. Removal of Polycomb Repressive Complex 2 Makes C. elegans Germ Cells Susceptible to Direct Conversion into Specific Somatic Cell Types

    Directory of Open Access Journals (Sweden)

    Tulsi Patel

    2012-11-01

    Full Text Available How specific cell types can be directly converted into other distinct cell types is a matter of intense investigation with wide-ranging basic and biomedical implications. Here, we show that removal of the histone 3 lysine 27 (H3K27 methyltransferase Polycomb repressor complex 2 (PRC2 permits ectopically expressed, neuron-type-specific transcription factors (“terminal selectors” to convert Caenorhabditis elegans germ cells directly into specific neuron types. Terminal-selector-induced germ-cell-to-neuron conversion can be observed not only upon genome-wide loss of H3K27 methylation in PRC2(− animals but also upon genome-wide redistribution of H3K27 methylation patterns in animals that lack the H3K36 methyltransferase MES-4. Manipulation of the H3K27 methylation status not only permits conversion of germ cells into neurons but also permits hlh-1/MyoD-dependent conversion of germ cells into muscle cells, indicating that PRC2 protects the germline from the aberrant execution of multiple distinct somatic differentiation programs. Taken together, our findings demonstrate that the normally multistep process of development from a germ cell via a zygote to a terminally differentiated somatic cell type can be short-cut by providing an appropriate terminal selector transcription factor and manipulating histone methylation patterns.

  14. Polarization conversion based on an all-dielectric metasurface for optical fiber applications

    Science.gov (United States)

    Liu, Tongming; Yang, Sen; Tang, Donghua; Da, Haixia; Feng, Rui; Zhu, Tongtong; Sun, Fangkui; Ding, Weiqiang

    2017-08-01

    Polarization conversion (PC) in optical fiber is a very important operation in practice. To date, however, PC in fiber is usually achieved by coupling an external bulk element, or using the birefringence results from mechanically squeezing or coiling the fiber. In this paper, we propose a distinct approach for PC in optical fiber by introducing an all-dielectric metasurface in it, which has been proven to be compact, efficient and robust. Based on this approach, nearly perfect PCs from the linear polarization fundamental mode, i.e. {{LP}}01x mode to various other polarization modes, are achieved, including the {{LP}}01y mode, left/right-handed circular polarization mode, and also vector modes with radial and azimuthal polarizations. In addition, the fabrication of this all-dielectric-based metasurface is compatible with semiconductor manufacturing technologies, which makes the PC presented here competitive against traditional ones, and may find potential applications in optical fiber elements and systems.

  15. Evaluation of the conversion of a VAX-based calorimeter to operation by a personal computer

    International Nuclear Information System (INIS)

    Perry, R.B.; Jung, E.A.; Pecos, J.M.; Cremers, T.L.; Foster, L.A.; Gutierrez, D.D.

    1994-01-01

    Water-bath calorimeters designed and built by EG ampersand G Mound Applied Technologies are used at the Los Alamos Plutonium Facility to perform assays of radioactive material. The data from these instruments are collected and analyzed by Digital Equipment Corporation PDP and VAX Computers. These computers are costly and have proved troublesome to maintain in the operating environment of the Plutonium Facility. We have converted one calorimeter to a PC-based-data-acquisition system (DAS) by replacing the PDP computer and associated electronics with an entirely new data collection system based on a 486 PC with an internal analog-to-digital conversion card (ADC). The new system has been tested with 238 Pu heat source standards and 239 Pu process items. The assay time, precision, and accuracy of these results are compared to those obtained with the original Mound Hardware

  16. Catalytic Conversion of Carbohydrates to Levulinate Ester over Heteropolyanion-Based Ionic Liquids.

    Science.gov (United States)

    Song, Changhua; Liu, Sijie; Peng, Xinwen; Long, Jinxing; Lou, Wenyong; Li, Xuehui

    2016-12-08

    An efficient one-pot approach for the production of levulinate ester from renewable carbohydrates is demonstrated over heteropolyanion-based ionic liquid (IL-POM) catalysts with alcohols as the promoters and solvents. The relationships between the structure, acidic strength, and solubility of the IL-POM in methanol and the catalytic performance were studied intensively. A cellulose conversion of 100 % could be achieved with a 71.4 % yield of methyl levulinate over the catalyst [PyPS] 3 PW 12 O 40 [PyPS=1-(3-sulfopropyl)pyridinium] at 150 °C for 5 h. This high efficiency is ascribed to the reasonably high activity of the ionic liquid (IL) catalyst and reaction coupling with rapid in situ esterification of the generated levulinic acid with the alcohol promoter, which allows the insolubility of cellulose encountered in biomass conversion to be overcome. Furthermore, the present process exhibits high feedstock adaptability for typical carbohydrates and handy catalyst recovery by a simple self-separation procedure through temperature control. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Inorganic hole conductor-based lead halide perovskite solar cells with 12.4% conversion efficiency

    KAUST Repository

    Qin, Peng

    2014-05-12

    Organo-lead halide perovskites have attracted much attention for solar cell applications due to their unique optical and electrical properties. With either low-temperature solution processing or vacuum evaporation, the overall conversion efficiencies of perovskite solar cells with organic hole-transporting material were quickly improved to over 15% during the last 2 years. However, the organic hole-transporting materials used are normally quite expensive due to complicated synthetic procedure or high-purity requirement. Here, we demonstrate the application of an effective and cheap inorganic p-type hole-transporting material, copper thiocyanate, on lead halide perovskite-based devices. With low-temperature solution-process deposition method, a power conversion efficiency of 12.4% was achieved under full sun illumination. This work represents a well-defined cell configuration with optimized perovskite morphology by two times of lead iodide deposition, and opens the door for integration of a class of abundant and inexpensive material for photovoltaic application. © 2014 Macmillan Publishers Limited.

  18. Direct conversion of surplus fissile materials, spent nuclear fuel, and other materials to high-level-waste glass

    International Nuclear Information System (INIS)

    Forsberg, C.W.; Elam, K.R.

    1995-01-01

    With the end of the cold war the United States, Russia, and other countries have excess plutonium and other materials from the reductions in inventories of nuclear weapons. The United States Academy of Sciences (NAS) has recommended that these surplus fissile materials (SFMs) be processed so they are no more accessible than plutonium in spent nuclear fuel (SNF). This spent fuel standard, if adopted worldwide, would prevent rapid recovery of SFMs for the manufacture of nuclear weapons. The NAS recommended investigation of three sets of options for disposition of SFMs while meeting the spent fuel standard: (1) incorporate SFMs with highly radioactive materials and dispose of as waste, (2) partly burn the SFMs in reactors with conversion of the SFMs to SNF for disposal, and (3) dispose of the SFMs in deep boreholes. The US Government is investigating these options for SFM disposition. A new method for the disposition of SFMs is described herein: the simultaneous conversion of SFMs, SNF, and other highly radioactive materials into high-level-waste (HLW) glass. The SFMs include plutonium, neptinium, americium, and 233 U. The primary SFM is plutonium. The preferred SNF is degraded SNF, which may require processing before it can be accepted by a geological repository for disposal

  19. Direct catalytic conversion of methane and light hydrocarbon gases. Quarterly report No. 4, August 16--October 15, 1987

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, R.B. Jr.; Chan, Yee Wai

    1987-11-19

    The goals of this research project are to increase the methane conversion and improve the hydrocarbon production. For methane reforming, we achieved a conversion of up to 43% by adjusting the reaction conditions. Ruthenium clusters are effective catalysts but the selectivity to hydrocarbons needs to be improved. In evaluating the effect of cluster size for mononuclear, tetranuclear, and hexanuclear ruthenium complexes we found that the tetraruthenium cluster was by far the most effective catalyst. We began to study the mixed metal catalysts by synthesizing a FeRu{sub 3} cluster. We plan to vary the ratio of Fe to Ru by synthesizing Fe{sub 2}Ru{sub 2} and Fe{sub 3}Ru clusters. The type of the support also plays an important role in methane reforming. We briefly tested a basic support, magnesia, in addition to the acidic supports tested previously (alumina, 5A molecular sieve, and Y-zeolite). The results are promising. We will continue to investigate the role of the support. The effectiveness of using a hydrogen removal membrane is still in question. We purchased a new Pd/Ag membrane tube inside which a stainless steel spring is inserted. The steel spring will increase the strength of the otherwise fragile tube and it will support the tube during bending. We will build a new reactor using this membrane tube.

  20. Low Noise and Highly Linear Wideband CMOS RF Front-End for DVB-H Direct-Conversion Receiver

    Science.gov (United States)

    Nam, Ilku; Moon, Hyunwon; Woo, Doo Hyung

    In this paper, a wideband CMOS radio frequency (RF) front-end for digital video broadcasting-handheld (DVB-H) receiver is proposed. The RF front-end circuit is composed of a single-ended resistive feedback low noise amplifier (LNA), a single-to-differential amplifier, an I/Q down-conversion mixer with linearized transconductors employing third order intermodulation distortion cancellation, and a divide-by-two circuit with LO buffers. By employing a third order intermodulation (IMD3) cancellation technique and vertical NPN bipolar junction transistor (BJT) switching pair for an I/Q down-conversion mixer, the proposed RF front-end circuit has high linearity and low low-frequency noise performance. It is fabricated in a 0.18µm deep n-well CMOS technology and draws 12mA from a 1.8V supply voltage. It shows a voltage gain of 31dB, a noise figure (NF) lower than 2.6dB, and an IIP3 of -8dBm from 470MHz to 862MHz.

  1. Determining the Optimal Capacities of Renewable-Energy-Based Energy Conversion Systems for Meeting the Demands of Low-Energy District Heating, Electricity, and District Cooling

    DEFF Research Database (Denmark)

    Tol, Hakan; Svendsen, Svend; Dincer, Ibrahim

    2015-01-01

    as 55 °C for supply and 25 °C for return, and with additional considerations being directed to supply electricity and cooling. Several optimal solutions with various nominal capacities of the technologies involved were obtained in each of the two case studies, one being for the Greater Copenhagen Area......, and the other for the Greater Toronto Area. Various climate conditions of the case areas in question caused different observations of nominal capacities for the energy conversion systems considered with single-production and multi-production based on different renewable energy sources.......This chapter presents a method for determining the optimal capacity of a renewable-energy-based energy conversion system for meeting the energy requirements of a given district as considered on a monthly basis, with use of a low-energy district heating system operating at a low temperature, as low...

  2. All-optical NRZ wavelength conversion based on a single hybrid III-V/Si SOA and optical filtering.

    Science.gov (United States)

    Wu, Yingchen; Huang, Qiangsheng; Keyvaninia, Shahram; Katumba, Andrew; Zhang, Jing; Xie, Weiqiang; Morthier, Geert; He, Jian-Jun; Roelkens, Gunther

    2016-09-05

    We demonstrate all-optical wavelength conversion (AOWC) of non-return-to-zero (NRZ) signal based on cross-gain modulation in a single heterogeneously integrated III-V-on-silicon semiconductor optical amplifier (SOA) with an optical bandpass filter. The SOA is 500 μm long and consumes less than 250 mW electrical power. We experimentally demonstrate 12.5 Gb/s and 40 Gb/s AOWC for both wavelength up and down conversion.

  3. Efficient Conversion of Lignin to Electricity Using a Novel Direct Biomass Fuel Cell Mediated by Polyoxomethalates at Low Temperatures

    Science.gov (United States)

    Xuebing Zhao; Junyong Zhu

    2016-01-01

    A novel polyoxometalates (POMs) mediated direct biomass fuelcelI (DBFC) was used in this study to directly convert lignin to electricity at low temperatures with high power output and Faradaic efficiency. When phosphomolybdic acid H3PMo12O40 (PMo12) was used as the electron and...

  4. VR-based conversation training program for patients with schizophrenia: a preliminary clinical trial.

    Science.gov (United States)

    Ku, Jeonghun; Han, Kiwan; Lee, Hyung Rae; Jang, Hee Jeong; Kim, Kwang Uk; Park, Sung Hyouk; Kim, Jae Jin; Kim, Chan Hyung; Kim, In Young; Kim, Sun I

    2007-08-01

    Schizophrenia is a devastating mental illness and is characterized by hallucinations and delusions as well as social skills deficits. Generally, social skills training designed to help patients develop social skills includes role-playing, but this form of training has typical shortcomings, which are largely due to a trainer's difficulties to project emotion. Virtual reality (VR)-based techniques have the potential to solve these difficulties, because they provide a computer-generated but realistic three-dimensional world and humanlike avatars that can provide emotional stimuli. In this paper, we report on a method of implementing virtual environments (VEs) in order to train people with schizophrenia to develop conversational skills in specific situations, which could overcome the shortcomings of or complement conventional role-playing techniques. The paper reports the efficacy of the proposed approach in a preliminary clinical trial with 10 patients with schizophrenia.

  5. The Chirality Conversion Reagent for Amino Acids Based on Salicyl Aldehyde

    International Nuclear Information System (INIS)

    Yoon, Hoe Jin; Jung, He In; Kim, Jun Soo; Kim, Kwan Mook; Ahn, Yun Soo; Nandhakumar, Raju

    2012-01-01

    2-Hydroxy-6-(1-(3-phenylurylphenyl)ethoxy)-benzaldehyde (2) has been synthesized in racemic form from 1,3-Dihydroxybenzene via formylation and reaction with 3-phenyluryl-methylbenzylbromide. The optically pure form of 2 was separated by normal silica column chromatography from the imine diastreomer which was obtained by the reaction of racemic mixture of 2 with optically pure leucinol. The absolute configuration of the separated enantiomer of 2 was decided from the energy calculation of the corresponding imine diastereomers. The activity of 2 as a chirality conversion reagent (CCR) for amino acids was determined by 1 H NMR analysis. The efficiency of 2 is not better than the previous CCRs based on binaththol. Compound 2, however, has lower molecular weight compared to other CCRs. This work demonstrates that asymmetric carbon can control the selectivity of amino acids

  6. A current controlled matrix converter for wind energy conversion systems based on permanent magnet synchronous generator

    Directory of Open Access Journals (Sweden)

    Naggar H. Saad

    2016-05-01

    Full Text Available The main challenges of wind energy conversion systems (WECS are to maximize the energy capture from the wind and injecting reactive power during the fault. This paper presents a current controlled matrix converter to interface Permanent Magnet Synchronous Generators (PMSG based WECS with the grid. To achieve fast dynamic response with reduced current ripples, a hysteresis current control is utilized. The proposed control system decouples the active and reactive components of the PMSG current to extract the maximum power from the wind at a given wind velocity and to inject reactive power to the grid. Reactive power injection during the fault satisfying the grid-codes requirement. The proposed WECS has been modeled and simulated using PSCAD/EMTDC software package.

  7. Remanufacture of Zirconium-Based Conversion Coatings on the Surface of Magnesium Alloy

    Science.gov (United States)

    Liu, Zhe; Jin, Guo; Song, Jiahui; Cui, Xiufang; Cai, Zhaobing

    2017-04-01

    Brush plating provides an effective method for creating a coating on substrates of various shapes. A corroded zirconium-based conversion coating was removed from the surface of a magnesium alloy and then replaced with new coatings prepared via brush plating. The structure and composition of the remanufactured coating were determined via x-ray photoelectron spectroscopy, x-ray diffraction, and Fourier transform infrared spectroscopy. The results revealed that the coatings consist of oxide, fluoride, and tannin-related organics. The composition of the coatings varied with the voltage. Furthermore, as revealed via potentiodynamic polarization spectroscopy, these coatings yielded a significant increase in the corrosion resistance of the magnesium alloy. The friction coefficient remained constant for almost 300s during wear resistance measurements performed under a 1-N load and dry sliding conditions, indicating that the remanufactured coatings provide effective inhibition to corrosion.

  8. CRISPR-UnLOCK: Multipurpose Cas9-Based Strategies for Conversion of Yeast Libraries and Strains.

    Science.gov (United States)

    Roggenkamp, Emily; Giersch, Rachael M; Wedeman, Emily; Eaton, Muriel; Turnquist, Emily; Schrock, Madison N; Alkotami, Linah; Jirakittisonthon, Thitikan; Schluter-Pascua, Samantha E; Bayne, Gareth H; Wasko, Cory; Halloran, Megan; Finnigan, Gregory C

    2017-01-01

    Saccharomyces cerevisiae continues to serve as a powerful model system for both basic biological research and industrial application. The development of genome-wide collections of individually manipulated strains (libraries) has allowed for high-throughput genetic screens and an emerging global view of this single-celled Eukaryote. The success of strain construction has relied on the innate ability of budding yeast to accept foreign DNA and perform homologous recombination, allowing for efficient plasmid construction ( in vivo ) and integration of desired sequences into the genome. The development of molecular toolkits and "integration cassettes" have provided fungal systems with a collection of strategies for tagging, deleting, or over-expressing target genes; typically, these consist of a C-terminal tag (epitope or fluorescent protein), a universal terminator sequence, and a selectable marker cassette to allow for convenient screening. However, there are logistical and technical obstacles to using these traditional genetic modules for complex strain construction (manipulation of many genomic targets in a single cell) or for the generation of entire genome-wide libraries. The recent introduction of the CRISPR/Cas gene editing technology has provided a powerful methodology for multiplexed editing in many biological systems including yeast. We have developed four distinct uses of the CRISPR biotechnology to generate yeast strains that utilizes the conversion of existing, commonly-used yeast libraries or strains. We present Cas9-based, marker-less methodologies for (i) N-terminal tagging, (ii) C-terminally tagging yeast genes with 18 unique fusions, (iii) conversion of fluorescently-tagged strains into newly engineered (or codon optimized) variants, and finally, (iv) use of a Cas9 "gene drive" system to rapidly achieve a homozygous state for a hypomorphic query allele in a diploid strain. These CRISPR-based methods demonstrate use of targeting universal sequences

  9. Power Conversion Efficiency of Arylamine Organic Dyes for Dye-Sensitized Solar Cells (DSSCs) Explicit to Cobalt Electrolyte: Understanding the Structural Attributes Using a Direct QSPR Approach

    OpenAIRE

    Supratik Kar; Juganta K. Roy; Danuta Leszczynska; Jerzy Leszczynski

    2016-01-01

    Post silicon solar cell era involves light-absorbing dyes for dye-sensitized solar systems (DSSCs). Therefore, there is great interest in the design of competent organic dyes for DSSCs with high power conversion efficiency (PCE) to bypass some of the disadvantages of silicon-based solar cell technologies, such as high cost, heavy weight, limited silicon resources, and production methods that lead to high environmental pollution. The DSSC has the unique feature of a distance-dependent electron...

  10. Research progress of infrared detecting and display integrated device based on infrared-visible up-conversion technology

    Science.gov (United States)

    Xu, Junfeng; Li, Weile; He, Bo; Wang, Haowei; Song, Yong; Yang, Shengyi; Ni, Guoqiang

    2018-01-01

    Infrared detecting and display device - IR-DDD - is a newly developed optical up-conversion device that integrates the light-emitting diode - LED - onto the infrared - IR - photo-detector, in order to convert IR light into the carriers photo-generated in detection materials and inject them into LED to emit visible light. This IR-DDD can achieve the direct up-conversion from IR ray to visible light, showing the considerable potential in night-vision application. This paper attempts a review of its working principle and current research progresses.

  11. Theoretical Conversions of Different Hardness and Tensile Strength for Ductile Materials Based on Stress-Strain Curves

    Science.gov (United States)

    Chen, Hui; Cai, Li-Xun

    2018-04-01

    Based on the power-law stress-strain relation and equivalent energy principle, theoretical equations for converting between Brinell hardness (HB), Rockwell hardness (HR), and Vickers hardness (HV) were established. Combining the pre-existing relation between the tensile strength ( σ b ) and Hollomon parameters ( K, N), theoretical conversions between hardness (HB/HR/HV) and tensile strength ( σ b ) were obtained as well. In addition, to confirm the pre-existing σ b -( K, N) relation, a large number of uniaxial tensile tests were conducted in various ductile materials. Finally, to verify the theoretical conversions, plenty of statistical data listed in ASTM and ISO standards were adopted to test the robustness of the converting equations with various hardness and tensile strength. The results show that both hardness conversions and hardness-strength conversions calculated from the theoretical equations accord well with the standard data.

  12. Energy-based coordinated control of wind energy conversion system with DFIG

    Science.gov (United States)

    Qu, Y. B.; Song, H. H.

    2011-12-01

    This article presents an energy-based coordinated control of machine- and grid-side converters in a wind energy conversion system (WECS) with a doubly-fed induction generator (DFIG) based on the theory of port-controlled Hamiltonian (PCH) system. Taking into account energy transmission in the dual PWM converter rather than treating rectification and inversion as separate parts, an integrated PCH model for the whole WECS was established from physical meanings. And depending on the new model, an energy-based coordinated control approach was proposed to meet the control requirements of the WECS with an additional objective which was to limit the DC-link voltage fluctuation. The approach was applied on a 2MW WECS, and compared with the energy-based respective control strategy using MATLAB/Simulink. The results show that the proposed control approach provides faster dynamic performance since the two converters operate with the knowledge of each other's operating status, and thus is able to smooth the power flow in the DC-link more effectively.

  13. Convincing Conversations : Using a Computer-Based Dialogue System to Promote a Plant-Based Diet

    NARCIS (Netherlands)

    Zaal, Emma; Mills, Gregory; Hagen, Afke; Huisman, Carlijn; Hoeks, Jacobus

    2017-01-01

    In this study, we tested the effectiveness of a computer-based persuasive dialogue system designed to promote a plant-based diet. The production and consumption of meat and dairy has been shown to be a major cause of climate change and a threat to public health, bio-diversity, animal rights and

  14. Nanostructured Mn-based oxides for electrochemical energy storage and conversion.

    Science.gov (United States)

    Zhang, Kai; Han, Xiaopeng; Hu, Zhe; Zhang, Xiaolong; Tao, Zhanliang; Chen, Jun

    2015-02-07

    Batteries and supercapacitors as electrochemical energy storage and conversion devices are continuously serving for human life. The electrochemical performance of batteries and supercapacitors depends in large part on the active materials in electrodes. As an important family, Mn-based oxides have shown versatile applications in primary batteries, secondary batteries, metal-air batteries, and pseudocapacitors due to their high activity, high abundance, low price, and environmental friendliness. In order to meet future market demand, it is essential and urgent to make further improvements in energy and power densities of Mn-based electrode materials with the consideration of multiple electron reaction and low molecular weight of the active materials. Meanwhile, nanomaterials are favourable to achieve high performance by means of shortening the ionic diffusion length and providing large surface areas for electrode reactions. This article reviews the recent efforts made to apply nanostructured Mn-based oxides for batteries and pseudocapacitors. The influence of structure, morphology, and composition on electrochemical performance has been systematically summarized. Compared to bulk materials and notable metal catalysts, nanostructured Mn-based oxides can promote the thermodynamics and kinetics of the electrochemical reactions occurring at the solid-liquid or the solid-liquid-gas interface. In particular, nanostructured Mn-based oxides such as one-dimensional MnO2 nanostructures, MnO2-conductive matrix nanocomposites, concentration-gradient structured layered Li-rich Mn-based oxides, porous LiNi0.5Mn1.5O4 nanorods, core-shell structured LiMnSiO4@C nanocomposites, spinel-type Co-Mn-O nanoparticles, and perovskite-type CaMnO3 with micro-nano structures all display superior electrochemical performance. This review should shed light on the sustainable development of advanced batteries and pseudocapacitors with nanostructured Mn-based oxides.

  15. Accelerator-based conversion (ABC) of weapons plutonium: Plant layout study and related design issues

    Energy Technology Data Exchange (ETDEWEB)

    Cowell, B.S.; Fontana, M.H. [Oak Ridge National Lab., TN (United States); Krakowski, R.A.; Beard, C.A.; Buksa, J.J.; Davidson, J.W.; Sailor, W.C.; Williamson, M.A. [Los Alamos National Lab., NM (United States)

    1995-04-01

    In preparation for and in support of a detailed R and D Plan for the Accelerator-Based Conversion (ABC) of weapons plutonium, an ABC Plant Layout Study was conducted at the level of a pre-conceptual engineering design. The plant layout is based on an adaptation of the Molten-Salt Breeder Reactor (MSBR) detailed conceptual design that was completed in the early 1070s. Although the ABC Plant Layout Study included the Accelerator Equipment as an essential element, the engineering assessment focused primarily on the Target; Primary System (blanket and all systems containing plutonium-bearing fuel salt); the Heat-Removal System (secondary-coolant-salt and supercritical-steam systems); Chemical Processing; Operation and Maintenance; Containment and Safety; and Instrumentation and Control systems. Although constrained primarily to a reflection of an accelerator-driven (subcritical) variant of MSBR system, unique features and added flexibilities of the ABC suggest improved or alternative approaches to each of the above-listed subsystems; these, along with the key technical issues in need of resolution through a detailed R&D plan for ABC are described on the bases of the ``strawman`` or ``point-of-departure`` plant layout that resulted from this study.

  16. Novel fabrication of immunochromatographic assay based on up conversion phosphors for sensitive detection of clenbuterol.

    Science.gov (United States)

    Wang, Peilong; Wang, Ruiguo; Zhang, Wei; Su, Xiaoou; Luo, Haifeng

    2016-03-15

    A novel and ultra sensitive immunochromatographic assay sensor (ICA) based on up conversion phosphor (UCP) for quantitative detection of clenbuterol (CL) was developed. Monoclonal antibody against CL was labeled with UCP beads. The detection strategy is based on competitive immunoreaction between CL antibodies conjugated to UCP beads and CL or CL antigen on the UCP-ICA sensor. It enables ultra sensitive detection of CL in one single test without complicated sample preparation. Sensing results can be obtained within 10 min. Under optimized conditions, visual limit of detection (vLOD) of UCP-ICA for CL was 0.1 ng/mL. Calculated LOD (cLOD) for CL, as low as 0.01 ng/mL, could be achieved with the UCP-ICA sensor. Recoveries of CL in various sample matrixes ranged from 73.0% to 92.2% and relative standard deviations (RSD) were below 12%. The assay was evaluated with spiked and real samples and the results were compared with liquid chromatography-tandem mass. The developed novel assay method based on UCP could be a potential alternative format for on site and rapid detection of CL as well as other illegal drugs. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Copper Oxide Thin Films through Solution Based Methods for Electrical Energy Conversion and Storage

    Science.gov (United States)

    Zhu, Changqiong

    Copper oxides (Cu2O and CuO), composed of non-toxic and earth abundant elements, are promising materials for electrical energy generation and storage devices. Solution based techniques for creating thin films of these materials, such as electrodeposition, are important to understand and develop because of their potential for realizing substantial energy savings compared to traditional fabrication methods. Cuprous oxide (Cu2O), with its direct band gap, is a p-type semiconductor that is well suited for creating solution-processed photovoltaic devices (solar cells); several key advancements made toward this application are the primary focus of this thesis. Electrodeposition of single-phase, crystalline Cu2O thin films is demonstrated using previously unexplored, acidic lactate/Cu2+ solutions, which has provided additional understanding of the impacts of growth solution chemistry on film formation. The influence of pH on the resulting Cu2O thin film properties is revealed by using the same ligand (sodium lactate) at various solution pH values. Cu2O films grown from acidic lactate solutions can exhibit a distinctive flowerlike, dendritic morphology, in contrast to the faceted, dense films obtained using alkaline lactate solutions. Relative speciation distributions of the various metal complex ions present under different growth conditions are calculated using reported equilibrium association constants and experimentally supported by UV-Visible absorption spectroscopy. Dependence of thin film morphology on the lactate/Cu2+ molar ratio and applied potential is described. Cu2O/eutectic gallium-indium Schottky junction devices are formed and devices are tested under monochromatic green LED illumination. Further surface examination of the Cu2O films using X-ray photoelectron spectroscopy (XPS) reveals the fact that films grown from acidic lactate solution with a small lactate/Cu2+ molar ratio, which exhibit improved photovoltaic performance compared to films grown from

  18. Motor Controlled Rotating Base for Directional Submarine Antennas

    Science.gov (United States)

    2012-09-28

    steel gear 172 that is attached to the rotating platform 150. [0044] Suitable motors include, but are not limited to, a brushless DC motor that...DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE Motor Controlled Rotating Base For Directional Submarine Antennas 5a. CONTRACT NUMBER...Std Z39-18 Attorney Docket No. 101658 Page 1 of 23 MOTOR CONTROLLED ROTATING BASE FOR DIRECTIONAL SUBMARINE ANTENNAS STATEMENT OF GOVERNMENT

  19. Developing Interactional Competence through Video-Based Computer-Mediated Conversations: Beginning Learners of Spanish

    Science.gov (United States)

    Tecedor Cabrero, Marta

    2013-01-01

    This dissertation examines the discourse produced by beginning learners of Spanish using social media. Specifically, it looks at the use and development of interactional resources during two video-mediated conversations. Through a combination of Conversation Analysis tools and quantitative data analysis, the use of turn-taking strategies, repair…

  20. Stability of Transition-metal Carbides in Liquid Phase Reactions Relevant for Biomass-Based Conversion

    NARCIS (Netherlands)

    Souza Macêdo, L.; Stellwagen, D.R.; Teixeira da Silva, V.; Bitter, J.H.

    2015-01-01

    Transition-metal carbides have been employed for biobased conversions aiming to replace the rare noble metals. However, when reactions are in liquid phase, many authors have observed catalyst deactivation. The main routes of deactivation in liquid phase biobased conversions are coke deposition,

  1. Mode-selective wavelength conversion based on four-wave mixing in a multimode silicon waveguide

    DEFF Research Database (Denmark)

    Ding, Yunhong; Xu, Jing; Ou, Haiyan

    2014-01-01

    We propose and demonstrate all-optical mode-selective wavelength conversion in a silicon waveguide. The mode-selective wavelength conversion relies on strong four-wave mixing when pump and signal light are on the same spatial mode, while weak four-wave mixing is obtained between different modes due...

  2. Study of aerosol direct and indirect effects and auto-conversion processes over the West African monsoon region using a regional climate model

    Science.gov (United States)

    Salah, Zeinab; Shalaby, Ahmed; Steiner, Allison L.; Zakey, Ashraf S.; Gautam, Ritesh; Abdel Wahab, Mohamed M.

    2018-02-01

    This study assesses the direct and indirect effects of natural and anthropogenic aerosols (e.g., black carbon and sulfate) over West and Central Africa during the West African monsoon (WAM) period (June-July-August). We investigate the impacts of aerosols on the amount of cloudiness, the influences on the precipitation efficiency of clouds, and the associated radiative forcing (direct and indirect). Our study includes the implementation of three new formulations of auto-conversion parameterization [namely, the Beheng (BH), Tripoli and Cotton (TC) and Liu and Daum (R6) schemes] in RegCM4.4.1, besides the default model's auto-conversion scheme (Kessler). Among the new schemes, BH reduces the precipitation wet bias by more than 50% over West Africa and achieves a bias reduction of around 25% over Central Africa. Results from detailed sensitivity experiments suggest a significant path forward in terms of addressing the long-standing issue of the characteristic wet bias in RegCM. In terms of aerosol-induced radiative forcing, the impact of the various schemes is found to vary considerably (ranging from -5 to -25 W m-2).

  3. Zirconium-based conversion film formation on zinc, aluminium and magnesium oxides and their interactions with functionalized molecules

    Science.gov (United States)

    Fockaert, L. I.; Taheri, P.; Abrahami, S. T.; Boelen, B.; Terryn, H.; Mol, J. M. C.

    2017-11-01

    Zirconium-based conversion treatment of zinc, aluminium and magnesium oxides have been studied in-situ using ATR-FTIR in a Kretschmann geometry. This set-up was coupled to an electrochemical cell, which allowed to obtain chemical and electrochemical information simultaneously as a function of conversion time. This elucidated the strong relation between physico-chemical surface properties and zirconium-based conversion kinetics. Whereas the surface hydroxyl density of zinc and aluminium increased during conversion, magnesium (hydr)oxide was shown to dissolve in the acid solution. Due to this dissolution, strong surface alkalization can be expected, explaining the rapid conversion kinetics. AES depth profiling was used to determine the final oxide thickness and elemental composition. This confirmed that magnesium is most active and forms a zirconium oxide layer approximately 10 times thicker than zinc. On the other hand, the presence of zirconium oxide on aluminium is very low and can be considered as not fully covering the metal oxide. Additionally, the converted oxide chemistry was related to the bonding mechanisms of amide functionalized molecules using ATR-FTIR and XPS. It was shown that inclusion of zirconium altered the acid-base properties, increasing the substrate proton donating capabilities in case of magnesium oxide and increasing hydrogen bonding and Bronsted interactions due to increased surface hydroxide fractions on zinc and aluminium substrates.

  4. High Photon-to-Current Conversion in Solar Cells Based on Light-Absorbing Silver Bismuth Iodide.

    Science.gov (United States)

    Zhu, Huimin; Pan, Mingao; Johansson, Malin B; Johansson, Erik M J

    2017-06-22

    Here, a lead-free silver bismuth iodide (AgI/BiI 3 ) with a crystal structure with space group R3‾ m is investigated for use in solar cells. Devices based on the silver bismuth iodide deposited from solution on top of TiO 2 and the conducting polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) as a hole-transport layer are prepared and the photovoltaic performance is very promising with a power conversion efficiency over 2 %, which is higher than the performance of previously reported bismuth-halide materials for solar cells. Photocurrent generation is observed between 350 and 700 nm, and the maximum external quantum efficiency is around 45 %. The results are compared to solar cells based on the previously reported material AgBi 2 I 7 , and we observe a clearly higher performance for the devices with the new silver and bismuth iodides composition and different crystal structure. The X-ray diffraction spectrum of the most efficient silver bismuth iodide material shows a hexagonal crystal structure with space group R3‾ m, and from the light absorption spectrum we obtain an indirect band gap energy of 1.62 eV and a direct band gap energy of 1.85 eV. This report shows the possibility for finding new structures of metal-halides efficient in solar cells and points out new directions for further exploration of lead-free metal-halide solar cells. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  5. ERI APRILIYANTO LITERACY-BASED APPROACH IN INTERPERSONAL AND TRANSACTIONAL CONVERSATION CLASS

    Directory of Open Access Journals (Sweden)

    Arif Suryo Priyatmojo

    2017-04-01

    Full Text Available Teachers at higher educations need to enlighten their students by introducing literacy, as it can be considerd as one approach to solve the endless problems in Indonesia. In doing so, discussion in classes by issuing students’ different problems of their own kowledge based on media they are interested to read, see, listen or watch can be one way to improve students’ literacy. This study is aimed at improving students literacy through discussion in classes. This is an action research in which one interpersonal and transactional class became the subject of the study. The result of the study shows that a number of problems become the main discussions in classes. Such problems are corruption, multicultural clash, moral degradation, double-standard democracy, humanism ignorance, education pragmatism and terrorism. The students discussed such problems in the interpersonal and transactional conversation class through small group discussions. Based on the findings, the students start concerning to solve those problems by sharing and giving their voices. Moreover, they also tried to give solutions to solve such problems using their varied ways and this triggered students’ awareness to respect others for their different points of view. They can use language to link the gap between the language and its relation to the world or themselves.

  6. Conversion of borate-based glass scaffold to hydroxyapatite in a dilute phosphate solution.

    Science.gov (United States)

    Liu, Xin; Pan, Haobo; Fu, Hailuo; Fu, Qiang; Rahaman, Mohamed N; Huang, Wenhai

    2010-02-01

    Porous scaffolds of a borate-based glass (composition in mol%: 6Na2O, 8K2O, 8MgO, 22CaO, 36B2O3, 18SiO2, 2P2O5), with interconnected porosity of approximately 70% and pores of size 200-500 microm, were prepared by a polymer foam replication technique. The degradation of the scaffolds and conversion to a hydroxyapatite-type material in a 0.02 M K2HPO4 solution (starting pH = 7.0) at 37 degrees C were studied by measuring the weight loss of the scaffolds, as well as the pH and the boron concentration of the solution. X-ray diffraction, scanning electronic microscopy and energy dispersive x-ray analysis showed that a hydroxyapatite-type material was formed on the glass surface within 7 days of immersion in the phosphate solution. Cellular response to the scaffolds was assessed using murine MLO-A5 cells, an osteogenic cell line. Scanning electron microscopy showed that the scaffolds supported cell attachment and proliferation during the 6 day incubation. The results indicate that this borate-based glass could provide a promising degradable scaffold material for bone tissue engineering applications.

  7. Efficient Conversion of Lignin to Electricity Using a Novel Direct Biomass Fuel Cell Mediated by Polyoxometalates at Low Temperatures.

    Science.gov (United States)

    Zhao, Xuebing; Zhu, J Y

    2016-01-01

    A novel polyoxometalates (POMs) mediated direct biomass fuel cell (DBFC) was used in this study to directly convert lignin to electricity at low temperatures with high power output and Faradaic efficiency. When phosphomolybdic acid H3 PMo12 O40 (PMo12) was used as the electron and proton carrier in the anode solution with a carbon electrode, and O2 was directly used as the final electron acceptor under the catalysis of Pt, the peak power density reached 0.96 mW cm(-2), 560 times higher than that of phenol-fueled microbial fuel cells (MFCs). When the cathode reaction was catalyzed by PMo12, the power density could be greatly enhanced to 5 mW cm(-2). Continuous operation demonstrated that this novel fuel cell was promising as a stable electrochemical power source. Structure analysis of the lignin indicated that the hydroxyl group content was reduced whereas the carbonyl group content increased. Both condensation and depolymerization takes place during the PMo12 oxidation of lignin. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Current status on preparation of dose conversion factors based on 1990 ICRP recommendations

    International Nuclear Information System (INIS)

    Yoshizawa, Michio

    1996-01-01

    The current status of arrangement of dose conversion factors for operational quantities are explained on the basis of 1995 ICRP-ICRU recommendations. The dose conversion factors of photon, neutron and electron were recommended by ICRP Publ. 74. It's contents are described. The relation between new dose conversion factors and the laws in connection with protecting radiation are explained. The dose conversion factors of 1 cm-, 3 mm- and 70 μm - dose equivalent which were introduced into the laws connected therewith in Japan are accepted the same values of ICRP Publ. 51 for photon and neutron. I mentioned the points of discussing about new dose conversion factors which are expected to be recommended. The laws have to show the dose conversion factors to be used by calculation and estimation of radiation shield, etc. The limit of energy of ICRU individual dose equivalent for photon is now until 1 MeV, but the value is insufficient and necessary to 10 MeV as same as the ambient dose equivalent in due consideration of atomic energy facilities. JAERI is preparing these dose conversion factors now. (S.Y.)

  9. Performance evaluation of a direct-conversion flat-panel detector system in imaging and quality assurance for a high-dose-rate 192Ir source

    Science.gov (United States)

    Miyahara, Yoshinori; Hara, Yuki; Nakashima, Hiroto; Nishimura, Tomonori; Itakura, Kanae; Inomata, Taisuke; Kitagaki, Hajime

    2018-03-01

    In high-dose-rate (HDR) brachytherapy, a direct-conversion flat-panel detector (d-FPD) clearly depicts a 192Ir source without image halation, even under the emission of high-energy gamma rays. However, it was unknown why iridium is visible when using a d-FPD. The purpose of this study was to clarify the reasons for visibility of the source core based on physical imaging characteristics, including the modulation transfer functions (MTF), noise power spectral (NPS), contrast transfer functions, and linearity of d-FPD to high-energy gamma rays. The acquired data included: x-rays, [X]; gamma rays, [γ] dual rays (X  +  γ), [D], and subtracted data for depicting the source ([D]  -  [γ]). In the quality assurance (QA) test for the positional accuracy of a source core, the coordinates of each dwelling point were compared between the planned and actual source core positions using a CT/MR-compatible ovoid applicator and a Fletcher-Williamson applicator. The profile curves of [X] and ([D]  -  [γ]) matched well on MTF and NPS. The contrast resolutions of [D] and [X] were equivalent. A strongly positive linear correlation was found between the output data of [γ] and source strength (r 2  >  0.99). With regard to the accuracy of the source core position, the largest coordinate difference (3D distance) was noted at the maximum curvature of the CT/MR-compatible ovoid and Fletcher-Williamson applicators, showing 1.74  ±  0.02 mm and 1.01  ±  0.01 mm, respectively. A d-FPD system provides high-quality images of a source, even when high-energy gamma rays are emitted to the detector, and positional accuracy tests with clinical applicators are useful in identifying source positions (source movements) within the applicator for QA.

  10. Performance evaluation of a direct-conversion flat-panel detector system in imaging and quality assurance for a high-dose-rate 192Ir source.

    Science.gov (United States)

    Miyahara, Yoshinori; Hara, Yuki; Nakashima, Hiroto; Nishimura, Tomonori; Itakura, Kanae; Inomata, Taisuke; Kitagaki, Hajime

    2018-03-08

    In high-dose-rate (HDR) brachytherapy, a direct-conversion flat-panel detector (d-FPD) clearly depicts a 192 Ir source without image halation, even under the emission of high-energy gamma rays. However, it was unknown why iridium is visible when using a d-FPD. The purpose of this study was to clarify the reasons for visibility of the source core based on physical imaging characteristics, including the modulation transfer functions (MTF), noise power spectral (NPS), contrast transfer functions, and linearity of d-FPD to high-energy gamma rays. The acquired data included: x-rays, [X]; gamma rays, [γ]; dual rays (X  +  γ), [D], and subtracted data for depicting the source ([D]  -  [γ]). In the quality assurance (QA) test for the positional accuracy of a source core, the coordinates of each dwelling point were compared between the planned and actual source core positions using a CT/MR-compatible ovoid applicator and a Fletcher-Williamson applicator. The profile curves of [X] and ([D]  -  [γ]) matched well on MTF and NPS. The contrast resolutions of [D] and [X] were equivalent. A strongly positive linear correlation was found between the output data of [γ] and source strength (r 2   >  0.99). With regard to the accuracy of the source core position, the largest coordinate difference (3D distance) was noted at the maximum curvature of the CT/MR-compatible ovoid and Fletcher-Williamson applicators, showing 1.74  ±  0.02 mm and 1.01  ±  0.01 mm, respectively. A d-FPD system provides high-quality images of a source, even when high-energy gamma rays are emitted to the detector, and positional accuracy tests with clinical applicators are useful in identifying source positions (source movements) within the applicator for QA.

  11. Process systems engineering issues and applications towards reducing carbon dioxide emissions through conversion technologies

    DEFF Research Database (Denmark)

    Roh, Kosan; Frauzem, Rebecca; Gani, Rafiqul

    2016-01-01

    This paper reviews issues and applications for design of sustainable carbon dioxide conversion processes, specifically through chemical conversion, and the integration of the conversion processes with other systems from a process systems engineering (PSE) view-point. Systematic and computer...... conversion processes with other systems including coexisting infrastructure and carbon dioxide sources is described.Then, the importance of PSE based studies for such application is discussed. Finally, some perspectives on the status and future directions of carbon dioxide conversion technology...

  12. Multi-mode dynamics of optical oscillators based on intracavity nonlinear frequency down-conversion

    Science.gov (United States)

    Morozov, Yuri A.

    2018-01-01

    The transient power characteristics of two optical oscillators—a difference frequency generator (ICDFG) and a singly resonant optical parametric oscillator (ICSRO)—based on intracavity nonlinear optical frequency conversion, are described. The simulation has been performed via the rate-equation mathematical model, which features a multi-mode behavior of all optical fields. The reason for unattainability of single-mode emission in these devices without an additional frequency-selective element (e.g., a Fabry-Perot etalon) is clarified. It is shown that the dynamics of a short-wavelength emission (pump) results mainly from the nonlinear optical interaction, while that of the longer-wavelength optical fields (signal and idler) depends on selectivity of the etalon. With the suitable etalons inserted in their cavities, both devices are shown to operate dynamically single-mode under conventional experimental conditions. The nonlinear interaction makes the pump emission collapse to the single-mode operation very fast (it takes no more than a few tens of the photon lifetimes). To overcome the threshold of parametric generation, the intracavity pump power in the ICSRO has to exceed ˜ 100 W, while the ICDFG is essentially a "thresholdless" device.

  13. Dielectric Elastomer Generator with Improved Energy Density and Conversion Efficiency Based on Polyurethane Composites.

    Science.gov (United States)

    Yin, Guoling; Yang, Yu; Song, Feilong; Renard, Christophe; Dang, Zhi-Min; Shi, Chang-Yong; Wang, Dongrui

    2017-02-15

    Dielectric elastomer generators (DEGs), which follow the physics of variable capacitors and harvest electric energy from mechanical work, have attracted intensive attention over the past decade. The lack of ideal dielectric elastomers, after nearly two decades of research, has become the bottleneck for DEGs' practical applications. Here, we fabricated a series of polyurethane-based ternary composites and estimated their potential as DEGs to harvest electric energy for the first time. Thermoplastic polyurethane (PU) with high relative permittivity (∼8) was chosen as the elastic matrix. Barium titanate (BT) nanoparticles and dibutyl phthalate (DBP) plasticizers, which were selected to improve the permittivity and mechanical properties, respectively, were blended into the PU matrix. As compared to pristine PU, the resultant ternary composite films fabricated through a solution casting approach showed enhanced permittivity, remarkably reduced elastic modulus, and relatively good electrical breakdown strength, dielectric loss, and strain at break. Most importantly, the harvested energy density of PU was significantly enhanced when blended with BT and DBP. A composite film containing 25 phr of BT and 60 phr of DBP with the harvested energy density of 1.71 mJ/cm 3 was achieved, which is about 4 times greater than that of pure PU and 8 times greater than that of VHB adhesives. Remarkably improved conversion efficiency of mechano-electric energy was also obtained via cofilling BT and DBP into PU. The results shown in this work strongly suggest compositing is a very promising way to provide better dielectric elastomer candidates for forthcoming practical DEGs.

  14. 3D graphene-based hybrid materials: synthesis and applications in energy storage and conversion.

    Science.gov (United States)

    Shi, Qiurong; Cha, Younghwan; Song, Yang; Lee, Jung-In; Zhu, Chengzhou; Li, Xiaoyu; Song, Min-Kyu; Du, Dan; Lin, Yuehe

    2016-08-25

    Porous 3D graphene-based hybrid materials (3D GBHMs) are currently attractive nanomaterials employed in the field of energy. Heteroatom-doped 3D graphene and metal, metal oxide, and polymer-decorated 3D graphene with modified electronic and atomic structures provide promising performance as electrode materials in energy storage and conversion. Numerous synthesis methods such as self-assembly, templating, electrochemical deposition, and supercritical CO2, pave the way to mass production of 3D GBHMs in the commercialization of energy devices. This review summarizes recent advances in the fabrication of 3D GBHMs with well-defined architectures such as finely controlled pore sizes, heteroatom doping types and levels. Moreover, current progress toward applications in fuel cells, supercapacitors and batteries employing 3D GBHMs is also highlighted, along with the detailed mechanisms of the enhanced electrochemical performance. Furthermore, current critical issues, challenges and future prospects with respect to applications of 3D GBHMs in practical devices are discussed at the end of this review.

  15. Semiconductor-based Multilayer Selective Solar Absorber for Unconcentrated Solar Thermal Energy Conversion.

    Science.gov (United States)

    Thomas, Nathan H; Chen, Zhen; Fan, Shanhui; Minnich, Austin J

    2017-07-13

    Solar thermal energy conversion has attracted substantial renewed interest due to its applications in industrial heating, air conditioning, and electricity generation. Achieving stagnation temperatures exceeding 200 °C, pertinent to these technologies, with unconcentrated sunlight requires spectrally selective absorbers with exceptionally low emissivity in the thermal wavelength range and high visible absorptivity for the solar spectrum. In this Communication, we report a semiconductor-based multilayer selective absorber that exploits the sharp drop in optical absorption at the bandgap energy to achieve a measured absorptance of 76% at solar wavelengths and a low emittance of approximately 5% at thermal wavelengths. In field tests, we obtain a peak temperature of 225 °C, comparable to that achieved with state-of-the-art selective surfaces. With straightforward optimization to improve solar absorption, our work shows the potential for unconcentrated solar thermal systems to reach stagnation temperatures exceeding 300 °C, thereby eliminating the need for solar concentrators for mid-temperature solar applications such as supplying process heat.

  16. Base-Catalyzed Depolymerization of Solid Lignin-Rich Streams Enables Microbial Conversion

    DEFF Research Database (Denmark)

    Rodriguez, Alberto; Salvachúa, Davinia; Katahira, Rui

    2017-01-01

    Lignin valorization offers significant potential to enhance the economic viability of lignocellulosic biorefineries. However, because of its heterogeneous and recalcitrant nature, conversion of lignin to value-added coproducts remains a considerable technical challenge. In this study, we employ b...

  17. High-Efficiency, Nanowire Based Thermoelectric Devices for Radioisotope Power Conversion, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I proposal responds to topic S3.03 of the 2010 NASA SBIR solicitation, for Power Generation and Conversion. Thermoelectric devices offer a simple and...

  18. Direct conversion from tramadol to tapentadol prolonged release for moderate to severe, chronic malignant tumour-related pain.

    Science.gov (United States)

    Kress, H G; Koch, E D; Kosturski, H; Steup, A; Karcher, K; Dogan, C; Etropolski, M; Eerdekens, M

    2016-10-01

    A recent randomized-withdrawal, active- and placebo-controlled, double-blind phase 3 study showed that tapentadol prolonged release (PR) was effective and well tolerated for managing moderate to severe, chronic malignant tumour-related pain in patients who were opioid naive or dissatisfied with current treatment (Pain Physician, 2014, 17, 329-343). This post hoc, subgroup analysis evaluated the efficacy and tolerability of tapentadol PR in patients who previously received and were dissatisfied with tramadol for any reason and who had a pain intensity ≥5 (11-point numerical rating scale) before converting directly to tapentadol PR. In the original study, eligible patients had been randomized (2:1) and titrated to their optimal dose of tapentadol PR (100-250 mg bid) or morphine sulphate-controlled release (40-100 mg bid) over 2 weeks. The present report focuses on results during the titration period for a subgroup of patients randomized to tapentadol PR after having been on tramadol treatment prior to randomization in the study (n = 129). Results for this subgroup are compared with results for all 338 patients who received tapentadol PR during titration (overall tapentadol PR group). Responder rates (responders: completed titration, mean pain intensity <5 [0-10 scale] and ≤20 mg/day rescue medication during last 3 days) were slightly better for the tramadol/tapentadol PR subgroup (69.8% [90/129]) vs. the overall tapentadol PR group (63.9% [214/335]). Tolerability profiles were comparable for both groups. Results of this subgroup analysis indicate that patients with cancer pain could safely switch from prior treatment with the weak centrally acting analgesic tramadol directly to the strong centrally acting analgesic tapentadol PR, for an improved analgesic therapy for severe pain. WHAT DOES THIS STUDY ADD?: Results of this post hoc analysis show that patients who had received prior tramadol therapy could switch directly to tapentadol PR, with the majority

  19. Smartphone-Based Conversational Agents and Responses to Questions About Mental Health, Interpersonal Violence, and Physical Health.

    Science.gov (United States)

    Miner, Adam S; Milstein, Arnold; Schueller, Stephen; Hegde, Roshini; Mangurian, Christina; Linos, Eleni

    2016-05-01

    Conversational agents are smartphone-based computer programs designed to respond to users in natural language, thereby mimicking conversations between people. Many people use their smartphones to obtain health information. To describe the responses of 4 widely used conversational agents (Siri [Apple], Google Now, S Voice [Samsung], and Cortana [Microsoft]) to a standardized panel of questions related to mental health, interpersonal violence, and physical health. A pilot study followed by a cross-sectional study of a convenience sample of 68 phones from 7 manufacturers conducted from December 2015 to January 2016. Investigators asked the smartphones 9 questions (3 each in mental health, interpersonal violence, and physical health) in their natural language. We recorded information on features of the smartphones and their software, including manufacturer, phone model, operating system version, and conversational agent. The primary outcomes were the responses of conversational agents to 9 questions. The responses were characterized based on the ability to (1) recognize a crisis, (2) respond with respectful language, and (3) refer to an appropriate helpline, or other health resources for a physical health concern. Questions were asked repeatedly until there were no new answers. The phones ran 77 conversational agents: Siri (n = 27), Google Now (n = 31), S Voice (n = 9), and Cortana (n = 10). Siri, Google Now, and S Voice recognized the statement "I want to commit suicide" as concerning; Siri and Google Now referred the user to a suicide prevention helpline. In response to "I am depressed," Siri recognized the concern and responded with respectful language, the responses from S Voice and Cortana varied, and Google Now did not recognize the concern. None of the conversational agents referred users to a helpline for depression. In response to "I was raped," Cortana referred to a sexual assault hotline; Siri, Google Now, and S Voice did not recognize the

  20. Cardinal Direction Relations Query Modeling Based on Geo-Ontology

    Science.gov (United States)

    Zhu, X.; Chen, D.; Zhou, C.; Li, M.; Xiao, W.

    2012-08-01

    Direction relations, as an important spatial relationship, is simply expressed as object prosperity in traditional geo-ontology. The lacking of explicit specifications and reasoning rules of direction relations in geo-ontology result in the difficult or inflexible of spatial reasoning. Also, digital gazetteers provide information on named features, linking the feature's name with its location and its type. Although the location information is incomplete and not exact, the implicit spatial information, for example spatial relationships and spatial scale, can be extract using the appropriate models based on geo-ontology. In this paper, we proposed a novel conceptual framework of direction relations in order to formalize the semantics and implicit information of direction relations, and present an extraction algorithm of implicit information based on previous researches, which will produce a complete query instance of direction relations. At last, the most suitable direction physical model is recommended to calculation module according to relevant rules. And the experimental results show that this direction query model not only extracted the implicit information effectively, but also made a reasonable interpretation for the user's intention.

  1. Biocatalytic conversion of methane to methanol as a key step for development of methane-based biorefineries.

    Science.gov (United States)

    Hwang, In Yeub; Lee, Seung Hwan; Choi, Yoo Seong; Park, Si Jae; Na, Jeong Geol; Chang, In Seop; Kim, Choongik; Kim, Hyun Cheol; Kim, Yong Hwan; Lee, Jin Won; Lee, Eun Yeol

    2014-12-28

    Methane is considered as a next-generation carbon feedstock owing to the vast reserves of natural and shale gas. Methane can be converted to methanol by various methods, which in turn can be used as a starting chemical for the production of value-added chemicals using existing chemical conversion processes. Methane monooxygenase is the key enzyme that catalyzes the addition of oxygen to methane. Methanotrophic bacteria can transform methane to methanol by inhibiting methanol dehydrogenase. In this paper, we review the recent progress made on the biocatalytic conversion of methane to methanol as a key step for methane-based refinery systems and discuss future prospects for this technology.

  2. Wave energy conversion utilizing vertical motion of water in the array of water chambers aligned in the direction of wave propagation

    Directory of Open Access Journals (Sweden)

    Kesayoshi Hadano

    2017-05-01

    Full Text Available As a new technical approach, wave energy converter by using vertical motion of water in the multiple water chambers were developed to realize actual wave power generation as eco-environmental renewable energy. And practical use of wave energy converter was actually to require the following conditions: (1 setting up of the relevant device and its application to wave power generation in case that severe wave loading is avoided; (2 workability in installation and maintenance operations; (3 high energy conversion potential; and (4 low cost. In this system, neither the wall(s of the chambers nor the energy conversion device(s are exposed to the impulsive load due to water wave. Also since this system is profitable when set along the jetty or along a long floating body, installation and maintenance are done without difficulty and the cost is reduced. In this paper, we describe the system which consists of a float, a shaft connected with another shaft, a rack and pinion arrangement, a ratchet mechanism, and rotary type generator(s. Then, we present the dynamics model for evaluating the output electric power, and the results of numerical calculation including the effect of the phase shift of up/down motion of the water in the array of water chambers aligned along the direction of wave propagation.

  3. Conversational sensemaking

    Science.gov (United States)

    Preece, Alun; Webberley, Will; Braines, Dave

    2015-05-01

    Recent advances in natural language question-answering systems and context-aware mobile apps create opportunities for improved sensemaking in a tactical setting. Users equipped with mobile devices act as both sensors (able to acquire information) and effectors (able to act in situ), operating alone or in collectives. The currently- dominant technical approaches follow either a pull model (e.g. Apple's Siri or IBM's Watson which respond to users' natural language queries) or a push model (e.g. Google's Now which sends notifications to a user based on their context). There is growing recognition that users need more flexible styles of conversational interaction, where they are able to freely ask or tell, be asked or told, seek explanations and clarifications. Ideally such conversations should involve a mix of human and machine agents, able to collaborate in collective sensemaking activities with as few barriers as possible. Desirable capabilities include adding new knowledge, collaboratively building models, invoking specific services, and drawing inferences. As a step towards this goal, we collect evidence from a number of recent pilot studies including natural experiments (e.g. situation awareness in the context of organised protests) and synthetic experiments (e.g. human and machine agents collaborating in information seeking and spot reporting). We identify some principles and areas of future research for "conversational sensemaking".

  4. Conversational sensing

    Science.gov (United States)

    Preece, Alun; Gwilliams, Chris; Parizas, Christos; Pizzocaro, Diego; Bakdash, Jonathan Z.; Braines, Dave

    2014-05-01

    Recent developments in sensing technologies, mobile devices and context-aware user interfaces have made it pos- sible to represent information fusion and situational awareness for Intelligence, Surveillance and Reconnaissance (ISR) activities as a conversational process among actors at or near the tactical edges of a network. Motivated by use cases in the domain of Company Intelligence Support Team (CoIST) tasks, this paper presents an approach to information collection, fusion and sense-making based on the use of natural language (NL) and controlled nat- ural language (CNL) to support richer forms of human-machine interaction. The approach uses a conversational protocol to facilitate a ow of collaborative messages from NL to CNL and back again in support of interactions such as: turning eyewitness reports from human observers into actionable information (from both soldier and civilian sources); fusing information from humans and physical sensors (with associated quality metadata); and assisting human analysts to make the best use of available sensing assets in an area of interest (governed by man- agement and security policies). CNL is used as a common formal knowledge representation for both machine and human agents to support reasoning, semantic information fusion and generation of rationale for inferences, in ways that remain transparent to human users. Examples are provided of various alternative styles for user feedback, including NL, CNL and graphical feedback. A pilot experiment with human subjects shows that a prototype conversational agent is able to gather usable CNL information from untrained human subjects.

  5. All-Optical Ultra-High-Speed OFDM to Nyquist-WDM Conversion Based on Complete Optical Fourier Transformation

    DEFF Research Database (Denmark)

    Guan, Pengyu; Røge, Kasper Meldgaard; Mulvad, Hans Christian Hansen

    2016-01-01

    We propose a novel all-optical ultra-high-speed orthogonal frequency-division multiplexing (OFDM) to Nyquist wavelength-division multiplexing (Nyquist-WDM) conversion scheme, achieved by exchanging the temporal and spectral profiles using a complete optical Fourier transformation (OFT). This scheme...... enables high-speed OFDM to Nyquist-WDM conversion without complex optical/electrical/optical conversion. The all-optical OFDM transmitter is based on the generation of OFDM symbols with a low duty cycle by rectangular temporal gating, which in combination with optical time-division multiplexing yields...... a higher symbol-rate OFDM signal. In the receiver, the converted Nyquist-WDM super-channel is WDM demultiplexed into individual Nyquist-WDM channels using a rectangular optical bandpass filter, followed by optical sampling at the intersymbol-interference free point. In the experimental demonstration...

  6. Insights into the deactivation mechanism of supported tungsten hydride on alumina (W-H/Al2O3) catalyst for the direct conversion of ethylene to propylene

    KAUST Repository

    Mazoyer, Etienne

    2014-04-01

    Tungsten hydride supported on alumina prepared by the surface organometallic chemistry method is an active precursor for the direct conversion of ethylene to propylene at low temperature and pressure. An extensive contact time study revealed that the dimerization of ethylene to 1-butene is the primary and also the rate limiting step. The catalytic cycle further involves isomerization of 1-butene to 2-butene, followed by cross-metathesis of ethylene and 2-butene to yield propylene with high selectivity. The deactivation mechanism of this reaction has been investigated. The used catalyst was extensively examined by DRIFTS, solid-state NMR, EPR, UV-Vis, TGA and DSC techniques. It was found that a large amount of carbonaceous species, which were due to side reaction like olefin polymerization took place with time on stream, significantly hindering the dimerization of ethylene to 1-butene and therefore the production of propylene. Crown Copyright © 2014 Published by Elsevier B.V. All rights reserved.

  7. First DMAP-mediated direct conversion of Morita–Baylis–Hillman alcohols into γ-ketoallylphosphonates: Synthesis of γ-aminoallylphosphonates

    Directory of Open Access Journals (Sweden)

    Marwa Ayadi

    2016-12-01

    Full Text Available An efficient synthesis of a series of γ-ketoallylphosphonates through a direct conversion of both primary and secondary Morita–Baylis–Hillman (MBH alcohols by trialkyl phosphites with or without DMAP, used as additive, and under solvent-free conditions, is described herein for the first time. Subsequently, a highly regioselective Luche reduction of the primary phosphonate 2a (R = H gave the corresponding γ-hydroxyallylphosphonate 5 that further reacted with tosylamines in the presence of diiodine (15 mol % as a catalyst, affording the corresponding SN2-type products 6a–d in 63 to 70% isolated yields. Alternatively, the alcohol 5 produced the corresponding acetate 7 which, mediated by Ce(III, was successfully converted into the corresponding γ-aminoallylphosphonates 8a–d.

  8. First DMAP-mediated direct conversion of Morita-Baylis-Hillman alcohols into γ-ketoallylphosphonates: Synthesis of γ-aminoallylphosphonates.

    Science.gov (United States)

    Ayadi, Marwa; Elleuch, Haitham; Vrancken, Emmanuel; Rezgui, Farhat

    2016-01-01

    An efficient synthesis of a series of γ-ketoallylphosphonates through a direct conversion of both primary and secondary Morita-Baylis-Hillman (MBH) alcohols by trialkyl phosphites with or without DMAP, used as additive, and under solvent-free conditions, is described herein for the first time. Subsequently, a highly regioselective Luche reduction of the primary phosphonate 2a (R = H) gave the corresponding γ-hydroxyallylphosphonate 5 that further reacted with tosylamines in the presence of diiodine (15 mol %) as a catalyst, affording the corresponding S N 2-type products 6a-d in 63 to 70% isolated yields. Alternatively, the alcohol 5 produced the corresponding acetate 7 which, mediated by Ce(III), was successfully converted into the corresponding γ-aminoallylphosphonates 8a-d .

  9. New development of large-area direct conversion detector for digital radiography using amorphous selenium with a C60-doped polymer layer

    Science.gov (United States)

    Nariyuki, F.; Imai, S.; Watano, H.; Nabeta, T.; Hosoi, Y.

    2010-04-01

    We have developed a novel direct conversion detector for digital radiography by using a fullerene (C60)-doped polymer layer added on a thick amorphous selenium (a-Se) layer coupled to an amorphous silicon thin-film transistor (a-Si TFT) array. This detector exhibits considerable improvement in the lag characteristics and durability in high ambient temperatures. The C60-doped polymer layer, which is directly and uniformly solution cast on the a-Se layer and followed by an inorganic electron-transporting layer, smoothly changes the electronic junction between the a-Se layer and the inorganic layer. It lubricates the emission of photocurrents from the a-Se photo-conversion layer and leads to the improved lag characteristics. Another merit of using a C60-doped polymer is that it is stabile in high-temperature ambient conditions and is not degraded by humidity or a large amount of X-ray exposure. The polymer layer prevents the crystallization of a-Se, which otherwise occurs on exposure of a-Se to high temperature not only during the deposition of the inorganic layer or the metal electrode layer in the manufacturing process but also in actual use. A prototype detector, with a size of 17 in × 17 in and a pixel pitch of 150 μm, exhibited a good resolution; its DQE is approximately 48% at 1 cy/mm in 258 μC/kg (RQA5). This new development can simplify cooling apparatus and detector modules and also make a wide range of operational environments available. In addition, the improved lag characteristics make it possible to reduce the exposure intervals for static imaging, tomosynthesis, and other various exposure techniques.

  10. Tracking Positioning Algorithm for Direction of Arrival Based on Direction Lock Loop

    Directory of Open Access Journals (Sweden)

    Xiu-Zhi Cheng

    2015-06-01

    Full Text Available In order to solve the problem of poor real-time performance, low accuracy and high computational complexity in the traditional process of locating and tracking of Direction of Arrival (DOA of moving targets, this paper proposes a DOA algorithm based on the Direction Lock Loop (DILL which adopts Lock Loop structure to realize the estimation and location of DOA and can adjust the direction automatically along with the changes of a signal’s angular variation to track the position of the signal. Meanwhile, to reduce the influence of nonlinearity and noise on its performance, the UKF filter is designed for eliminating interference of the estimated target signal to improve accuracy of the signal tracking and stability of the system. Simulation results prove that the algorithm can not only get a high resolution DOA estimate signal, but can also locate and track multiple mobile targets effectively with enhanced accuracy, efficiency and stability.

  11. Direct conversion of inulin into cell lipid by an inulinase-producing yeast Rhodosporidium toruloides 2F5.

    Science.gov (United States)

    Wang, Zhi-Peng; Fu, Wen-Juan; Xu, Hong-Mei; Chi, Zhen-Ming

    2014-06-01

    In this study, an inulinase-producing yeast strain 2F5 of Rhodosporidium toruloides was obtained. It was found that the yeast strain 2F5 could produce higher amount of oil from inulin and larger lipid bodies in its cells than any other yeast strains tested in this study. Under the optimal conditions, 62.14% (w/w) of lipid based on cell dry weight and 15.82g/l of the dry cell mass were produced from 6.0% (w/v) inulin at flask level, leaving 0.92% (w/v) of total sugar in the fermented medium. During 2-l fermentation, 70.36% (w/w) of lipid based on cell dry weight and 15.64g/l of the dry cell mass were produced from 6.0% (w/v) inulin. Over 99.09% of the fatty acids from the yeast strain 2F5 grown on inulin was C16:0, C18:0, C18:1 and C18:2, especially C18:1 (52.2%). The biodiesel prepared using the lipids produced by the yeast strain 2F5 could be burnt well. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Fault-tolerant conversion between adjacent Reed–Muller quantum codes based on gauge fixing

    Science.gov (United States)

    Quan, Dong-Xiao; Zhu, Li-Li; Pei, Chang-Xing; Sanders, Barry C.

    2018-03-01

    We design forward and backward fault-tolerant conversion circuits, which convert between the Steane code and the 15-qubit Reed–Muller quantum code so as to provide a universal transversal gate set. In our method, only seven out of a total 14 code stabilizers need to be measured, and we further enhance the circuit by simplifying some stabilizers; thus, we need only to measure eight weight-4 stabilizers for one round of forward conversion and seven weight-4 stabilizers for one round of backward conversion. For conversion, we treat random single-qubit errors and their influence on syndromes of gauge operators, and our novel single-step process enables more efficient fault-tolerant conversion between these two codes. We make our method quite general by showing how to convert between any two adjacent Reed–Muller quantum codes \\overline{\\textsf{RM}}(1,m) and \\overline{\\textsf{RM}}≤ft(1,m+1\\right) , for which we need only measure stabilizers whose number scales linearly with m rather than exponentially with m obtained in previous work. We provide the explicit mathematical expression for the necessary stabilizers and the concomitant resources required.

  13. A new type of Ce-Mo based conversion coatings for aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Li Di; Li Guoqiang; Guo Baolan; Peng Mingxia [Coll. of Materials Science and Engineering, Beijing Univ. of Aeronautics and Astronautics, Beijing, BJ (China)

    2002-07-01

    A new type of process for forming Ce-Mo conversion coatings on Al-alloys has been developed. Conversion coatings about 3.6 {mu}m thickness were obtained by immersing Al-alloys for 20 minutes in boiling film forming solutions containing (NH{sub 4}){sub 2}Ce(NO{sub 3}){sub 6} 2.5 g/l, NaKC{sub 4}H{sub 4}O{sub 6}.4H{sub 2}O 2.5 g/l, Na{sub 2}CO{sub 3} 7.5 g/l and Na{sub 2}MoO{sub 4} 5.0 g/l. In the case of LF4 Al-alloy, polarization curves and immersion tests in 5% NaCl indicated that the conversion coatings exhibited more excellent resistance to localized corrosion than the conventional chromate conversion coatings. However, its resistance to localized corrosion was not satisfactory on LC4 Al alloy. Scanning electron microscopy (SEM) and energy dispersion analyzer of X-ray (EDAX) analysis revealed that the conversion coatings having complex surface microstructure on both LC4 and LF6 Al alloys consist mainly of O, Al and other alloying elements in addition to significant Ce and Mo. A mechanism of film formation was proposed to explain the experimental results. (orig.)

  14. Anaerobic microplate assay for direct microbial conversion of switchgrass and Avicel using Clostridium thermocellum

    Energy Technology Data Exchange (ETDEWEB)

    Oguntimein, Gbekeloluwa B. [Morgan State Univ., Baltimore, MD (United States); Rodriguez, Jr., Miguel [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); National Lab., Oak Ridge, TN (United States). BioEnergy Science Center; Dumitrache, Alexandru [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); National Lab., Oak Ridge, TN (United States). BioEnergy Science Center; Shollenberger, Todd [National Renewable Energy Lab. (NREL), Golden, CO (United States); Decker, Stephen R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Davison, Brian H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); National Lab., Oak Ridge, TN (United States). BioEnergy Science Center; Brown, Steven D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); National Lab., Oak Ridge, TN (United States). BioEnergy Science Center; LanzaTech, Inc., Skokie, IL (United States)

    2017-11-09

    Here, to develop and prototype a high-throughput microplate assay to assess anaerobic microorganisms and lignocellulosic biomasses in a rapid, cost-effective screen for consolidated bioprocessing potential. Clostridium thermocellum parent Δhpt strain deconstructed Avicel to cellobiose, glucose, and generated lactic acid, formic acid, acetic acid and ethanol as fermentation products in titers and ratios similar to larger scale fermentations confirming the suitability of a plate-based method for C. thermocellum growth studies. C. thermocellum strain LL1210, with gene deletions in the key central metabolic pathways, produced higher ethanol titers in the Consolidated Bioprocessing (CBP) plate assay for both Avicel and switchgrass fermentations when compared to the Δhpt strain. A prototype microplate assay system is developed that will facilitate high-throughput bioprospecting for new lignocellulosic biomass types, genetic variants and new microbial strains for bioethanol production.

  15. Pixel extraction based integral imaging with controllable viewing direction

    International Nuclear Information System (INIS)

    Ji, Chao-Chao; Deng, Huan; Wang, Qiong-Hua

    2012-01-01

    We propose pixel extraction based integral imaging with a controllable viewing direction. The proposed integral imaging can provide viewers three-dimensional (3D) images in a very small viewing angle. The viewing angle and the viewing direction of the reconstructed 3D images are controlled by the pixels extracted from an elemental image array. Theoretical analysis and a 3D display experiment of the viewing direction controllable integral imaging are carried out. The experimental results verify the correctness of the theory. A 3D display based on the integral imaging can protect the viewer’s privacy and has huge potential for a television to show multiple 3D programs at the same time. (paper)

  16. Effect of Shade and Light Curing Mode on the Degree of Conversion of Silorane-Based and Methacrylate-Based Resin Composites.

    Science.gov (United States)

    Sm, Mousavinasab; M, Atai; N, Salehi; A, Salehi

    2016-12-01

    The degree of conversion depends on the material composition, light source properties, distance from light source, light intensity, curing time, and other factors such as shade and translucency. In the present study, we evaluated the effects of different light-curing modes and shades of methacrylate and silorane-based resin composites on the degree of conversion of resin composites (DC). The methacrylate-based (Filtek Z250, 3M, ESPE) and low-shrinkage silorane-based (Filtek P90, 3M, ESPE) resin composites were used in three groups as follows: group 1-Filtek Z250 (shade A3), group 2-Filtek Z250 (shade B2), and group 3-Filtek P90 (shade A3). We used a light-emitting diode (LED) curing unit for photopolymerization. 10 samples were prepared in each group to evaluate the degree of conversion; 5 samples were cured using soft-start curing mode, and the other 5 were cured using standard curing mode. The DC of the resin composites was measured using Fourier Transform Infrared Spectroscopy (FTIR). The data were analyzed using Kruskal Wallis and one-way ANOVA statistical tests. The degree of conversion of silorane-based resin composite was 70 - 75.8% and that of methacrylate-based resin composites was 60.2 - 68.2% (p = 0.009). The degree of conversion of the composite with brighter colour (B2) was statistically more than the darker composite (A3). Higher degree of conversion was achieved applying the standard curing mode. The results of the study showed that the colour and type of the resin composite and also the curing mode influence the degree of conversion of resin composites.

  17. CMOS-based avalanche photodiodes for direct particle detection

    International Nuclear Information System (INIS)

    Stapels, Christopher J.; Squillante, Michael R.; Lawrence, William G.; Augustine, Frank L.; Christian, James F.

    2007-01-01

    Active Pixel Sensors (APSs) in complementary metal-oxide-semiconductor (CMOS) technology are augmenting Charge-Coupled Devices (CCDs) as imaging devices and cameras in some demanding optical imaging applications. Radiation Monitoring Devices are investigating the APS concept for nuclear detection applications and has successfully migrated avalanche photodiode (APD) pixel fabrication to a CMOS environment, creating pixel detectors that can be operated with internal gain as proportional detectors. Amplification of the signal within the diode allows identification of events previously hidden within the readout noise of the electronics. Such devices can be used to read out a scintillation crystal, as in SPECT or PET, and as direct-conversion particle detectors. The charge produced by an ionizing particle in the epitaxial layer is collected by an electric field within the diode in each pixel. The monolithic integration of the readout circuitry with the pixel sensors represents an improved design compared to the current hybrid-detector technology that requires wire or bump bonding. In this work, we investigate designs for CMOS APD detector elements and compare these to typical values for large area devices. We characterize the achievable detector gain and the gain uniformity over the active area. The excess noise in two different pixel structures is compared. The CMOS APD performance is demonstrated by measuring the energy spectra of X-rays from 55 Fe

  18. Single base pair mutation analysis by PNA directed PCR clamping

    DEFF Research Database (Denmark)

    Ørum, H.; Nielsen, P.E.; Egholm, M.

    1993-01-01

    A novel method that allows direct analysis of single base mutation by the polymerase chain reaction (PCR) is described. The method utilizes the finding that PNAs (peptide nucleic acids) recognize and bind to their complementary nucleic acid sequences with higher thermal stability and specificity...

  19. Potential for GPC-based laser direct writing

    DEFF Research Database (Denmark)

    Bañas, Andrew; Glückstad, Jesper

    2016-01-01

    lasers for such applications by using phase modulation as opposed to amplitude truncating masks. Here, we explore GPC’s potential for increasing the yield of micropscopic 3D printing also known as direct laser writing. Many light based additive manufacturing techniques, adopt a point scanning approach...

  20. Sources, Developments and Directions of Task-Based Language Teaching

    Science.gov (United States)

    Bygate, Martin

    2016-01-01

    This paper provides an outline of the origins, the current shape and the potential directions of task-based language teaching (TBLT) as an approach to language pedagogy. It first offers a brief description of TBLT and considers its origins within language teaching methodology and second language acquisition. It then summarises the current position…

  1. Widely tunable wavelength conversion with extinction ratio enhancement using PCF-based NOLM

    DEFF Research Database (Denmark)

    Kwok, C.H.; Lee, S.H.; Chow, K.K.

    2005-01-01

    A widely tunable wavelength conversion scheme has been demonstrated using a 64-m-long dispersion-flattened high-nonlinearity photonic crystal fiber in a nonlinear optical loop mirror. Wavelength conversion range of over 60 nm with a 10-Gb/s return-to-zero signal was obtained with the output extin...... extinction ratio (ER) maintained above 13 dB. The proposed scheme can also improve the output ER and remove the bit-error-rate floor if a degraded signal is used....

  2. Feasibility study on AFR-100 fuel conversion from uranium-based fuel to thorium-based fuel

    Energy Technology Data Exchange (ETDEWEB)

    Heidet, F.; Kim, T.; Grandy, C. (Nuclear Engineering Division)

    2012-07-30

    Although thorium has long been considered as an alternative to uranium-based fuels, most of the reactors built to-date have been fueled with uranium-based fuel with the exception of a few reactors. The decision to use uranium-based fuels was initially made based on the technology maturity compared to thorium-based fuels. As a result of this experience, lot of knowledge and data have been accumulated for uranium-based fuels that made it the predominant nuclear fuel type for extant nuclear power. However, following the recent concerns about the extent and availability of uranium resources, thorium-based fuels have regained significant interest worldwide. Thorium is more abundant than uranium and can be readily exploited in many countries and thus is now seen as a possible alternative. As thorium-based fuel technologies mature, fuel conversion from uranium to thorium is expected to become a major interest in both thermal and fast reactors. In this study the feasibility of fuel conversion in a fast reactor is assessed and several possible approaches are proposed. The analyses are performed using the Advanced Fast Reactor (AFR-100) design, a fast reactor core concept recently developed by ANL. The AFR-100 is a small 100 MW{sub e} reactor developed under the US-DOE program relying on innovative fast reactor technologies and advanced structural and cladding materials. It was designed to be inherently safe and offers sufficient margins with respect to the fuel melting temperature and the fuel-cladding eutectic temperature when using U-10Zr binary metal fuel. Thorium-based metal fuel was preferred to other thorium fuel forms because of its higher heavy metal density and it does not need to be alloyed with zirconium to reduce its radiation swelling. The various approaches explored cover the use of pure thorium fuel as well as the use of thorium mixed with transuranics (TRU). Sensitivity studies were performed for the different scenarios envisioned in order to determine the

  3. Power Conversion Efficiency of Arylamine Organic Dyes for Dye-Sensitized Solar Cells (DSSCs Explicit to Cobalt Electrolyte: Understanding the Structural Attributes Using a Direct QSPR Approach

    Directory of Open Access Journals (Sweden)

    Supratik Kar

    2016-12-01

    Full Text Available Post silicon solar cell era involves light-absorbing dyes for dye-sensitized solar systems (DSSCs. Therefore, there is great interest in the design of competent organic dyes for DSSCs with high power conversion efficiency (PCE to bypass some of the disadvantages of silicon-based solar cell technologies, such as high cost, heavy weight, limited silicon resources, and production methods that lead to high environmental pollution. The DSSC has the unique feature of a distance-dependent electron transfer step. This depends on the relative position of the sensitized organic dye in the metal oxide composite system. In the present work, we developed quantitative structure-property relationship (QSPR models to set up the quantitative relationship between the overall PCE and quantum chemical molecular descriptors. They were calculated from density functional theory (DFT and time-dependent DFT (TD-DFT methods as well as from DRAGON software. This allows for understanding the basic electron transfer mechanism along with the structural attributes of arylamine-organic dye sensitizers for the DSSCs explicit to cobalt electrolyte. The identified properties and structural fragments are particularly valuable for guiding time-saving synthetic efforts for development of efficient arylamine organic dyes with improved power conversion efficiency.

  4. A direct methanol fuel cell system with passive fuel delivery based on liquid surface tension

    Science.gov (United States)

    Yang, Yuming; Liang, Yung C.

    The existing direct methanol fuel cell (DMFC) systems are fed with a fixed concentration of fuel, which are either a diluted methanol solution or an active fuel delivery driven by an attached active pump. Both approaches limit the power conversion density or degrade the overall efficiency of the DMFC system significantly. Such disadvantages become more severe in small-scale DMFCs, which require a high conversion efficiency and a small physical space suitable for portable electronics. In this paper, passive fuel delivery based on a surface tension driving mechanism was designed and integrated in a laboratory-made prototype to achieve consumption depending on fuel concentration and power-free fuel delivery. Unidirectional methanol-to-water smooth flow is achieved through the capillaries of a Teflon PTFE (polytetrafluoroethylene) membrane based on the difference in liquid surface tension. The prototype was demonstrated to exhibit a better polarization performance and to last for an extended operating time compared to conventional DMFCs. Its high efficiency and load regulation performance were also demonstrated in contrast to an active DMFC supplied with a constant concentration fuel. The fuel delivery driven by the liquid surface tension effect demonstrated here is believed to be more applicable for future small-scale DMFCs for portable electronics.

  5. Cr(VI) and Cr(III)-Based Conversion Coatings on Zinc

    NARCIS (Netherlands)

    Zhang, X.

    2005-01-01

    With the aims of understanding the protective mechanism of chromate conversion coatings and developing alternatives to chromate treatments, the physical natures and corrosion properties of Cr(VI) and Cr(III) treated zinc have been investigated in this work. The Cr(VI) treatments were carried out in

  6. The caring relationship in hospice care: an analysis based on the ethics of the caring conversation.

    NARCIS (Netherlands)

    Olthuis, G.J.; Dekkers, W.J.M.; Leget, C.J.W.; Vogelaar, P.J.W.

    2006-01-01

    Good nursing is more than exercising a specific set of skills. It involves the personal identity of the nurse. The aim of this article is to answer two questions: (1) what kind of person should the hospice nurse be? and (2) how should the hospice nurse engage in caring conversations? To answer these

  7. Hyper-local, directions-based ranking of places

    DEFF Research Database (Denmark)

    Venetis, Petros; Gonzalez, Hector; Jensen, Christian S.

    2011-01-01

    , enables so-called hyper-local web querying where the location of a user is accurate at a much finer granularity than with IP-based positioning. This paper addresses the problem of determining the importance of points of interest, or places, in local-search results. In doing so, the paper proposes......, including the frequency with which places have been referred to in directions queries. Next, the paper proposes an algorithm and accompanying data structures capable of ranking places in response to hyper-local web queries. Finally, an empirical study with very large directions query logs offers insight...

  8. Conversion disorder

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000954.htm Conversion disorder To use the sharing features on this page, please enable JavaScript. Conversion disorder is a mental condition in which a person ...

  9. Simulating the conversion of rural settlements to town land based on multi-agent systems and cellular automata.

    Science.gov (United States)

    Liu, Yaolin; Kong, Xuesong; Liu, Yanfang; Chen, Yiyun

    2013-01-01

    Rapid urbanization in China has triggered the conversion of land from rural to urban use, particularly the conversion of rural settlements to town land. This conversion is the result of the joint effects of the geographic environment and agents involving the government, investors, and farmers. To understand the dynamic interaction dominated by agents and to predict the future landscape of town expansion, a small town land-planning model is proposed based on the integration of multi-agent systems (MAS) and cellular automata (CA). The MAS-CA model links the decision-making behaviors of agents with the neighbor effect of CA. The interaction rules are projected by analyzing the preference conflicts among agents. To better illustrate the effects of the geographic environment, neighborhood, and agent behavior, a comparative analysis between the CA and MAS-CA models in three different towns is presented, revealing interesting patterns in terms of quantity, spatial characteristics, and the coordinating process. The simulation of rural settlements conversion to town land through modeling agent decision and human-environment interaction is very useful for understanding the mechanisms of rural-urban land-use change in developing countries. This process can assist town planners in formulating appropriate development plans.

  10. Energy conversion and utilization technologies

    International Nuclear Information System (INIS)

    1988-01-01

    The DOE Energy Conversion and Utilization Technologies (ECUT) Program continues its efforts to expand the generic knowledge base in emerging technological areas that support energy conservation initiatives by both the DOE end-use sector programs and US private industry. ECUT addresses specific problems associated with the efficiency limits and capabilities to use alternative fuels in energy conversion and end-use. Research is aimed at understanding and improving techniques, processes, and materials that push the thermodynamic efficiency of energy conversion and usage beyond the state of the art. Research programs cover the following areas: combustion, thermal sciences, materials, catalysis and biocatalysis, and tribology. Six sections describe the status of direct contact heat exchange; the ECUT biocatalysis project; a computerized tribology information system; ceramic surface modification; simulation of internal combustion engine processes; and materials-by-design. These six sections have been indexed separately for inclusion on the database. (CK)

  11. Direct Energy Conversion Literature Abstracts

    Science.gov (United States)

    1962-12-01

    state mid- ERDL TESTING THERMOELECTRIC AIR point temperature rise on DC with Peltier CONDITIONER . Army Res. and Devlpt. and Thomson heating in...type of air conditioner being tested at the U.S. Army 3109 Engineer Research and Development IMPULSE-OPERATION OF COOLING THER- Laboratories. Fort...efficiency and AIR FORCE CAREFULLY EVALUATES cost are lower and the output per unit 1000 PROPOSALS YEARLY, ACCEPTS 10%; weight apears high. INDUSTRY SHOULD

  12. Forward error correction supported 150 Gbit/s error-free wavelength conversion based on cross phase modulation in silicon

    DEFF Research Database (Denmark)

    Hu, Hao; Andersen, Jakob Dahl; Rasmussen, Anders

    2013-01-01

    We build a forward error correction (FEC) module and implement it in an optical signal processing experiment. The experiment consists of two cascaded nonlinear optical signal processes, 160 Gbit/s all optical wavelength conversion based on the cross phase modulation (XPM) in a silicon nanowire...... and subsequent 160 Gbit/s-to-10 Gbit/s demultiplexing in a highly nonlinear fiber (HNLF). The XPM based all optical wavelength conversion in silicon is achieved by off-center filtering the red shifted sideband on the CW probe. We thoroughly demonstrate and verify that the FEC code operates correctly after...... the optical signal processing, yielding truly error-free 150 Gbit/s (excl. overhead) optically signal processed data after the two cascaded nonlinear processes. © 2013 Optical Society of America....

  13. Secure Direct Communication Based on Secret Transmitting Order of Particles

    OpenAIRE

    Zhu, Ai-Dong; Xia, Yan; Fan, Qiu-Bo; Zhang, Shou

    2006-01-01

    We propose the schemes of quantum secure direct communication (QSDC) based on secret transmitting order of particles. In these protocols, the secret transmitting order of particles ensures the security of communication, and no secret messages are leaked even if the communication is interrupted for security. This strategy of security for communication is also generalized to quantum dialogue. It not only ensures the unconditional security but also improves the efficiency of communication.

  14. Self-directed simulation-based training of emergency cricothyroidotomy

    DEFF Research Database (Denmark)

    Melchiors, Jacob; Todsen, Tobias; Mørkeberg Nilsson, Philip

    2016-01-01

    The emergency cricothyroidotomy (EC) is a critical procedure. The high cost of failures increases the demand for evidence-based training methods. The aim of this study was to present and evaluate self-directed video-guided simulation training. Novice doctors were given an individual 1-h simulation...... during training (p competence level of novice doctors; however, the training did not ensure that all...

  15. A Model of FPGA-based Direct Torque Controller

    OpenAIRE

    Auzani Jidin; Aiman Zakwan Jidin; Nik Rumzi Nik Idris; Tole Sutikno

    2013-01-01

    This paper presents a generic model of a fully FPGA-based direct torque controller. This model is developed using two’s-complement fixed-point format approaches, in register-transfer-level (RTL) VHDL abstraction for minimizing calculation errors and consuming hardware resource usage. Therefore, the model is universal and can be implemented for all FPGA types. The model is prepared for fast computation, without using of CORDIC algorithm, a soft-core CPU, a transformation from Cartesian-to-pola...

  16. Secure direct communication based on secret transmitting order of particles

    International Nuclear Information System (INIS)

    Zhu Aidong; Zhang Shou; Xia Yan; Fan Qiubo

    2006-01-01

    We propose the schemes of quantum secure direct communication based on a secret transmitting order of particles. In these protocols, the secret transmitting order of particles ensures the security of communication, and no secret messages are leaked even if the communication is interrupted for security. This strategy of security for communication is also generalized to a quantum dialogue. It not only ensures the unconditional security but also improves the efficiency of communication

  17. Conversion of straight-run gas-condensate benzenes into high- octane gasolines based on modified ZSM-5 zeolites

    International Nuclear Information System (INIS)

    Erofeev, V; Reschetilowski, V; Khomajakov, I; Egorova, L; Volgina, T; Tatarkina, A

    2014-01-01

    This paper describes the conversion of straight-run benzene of gas condensate into high-octane gasoline based on zeolite catalyst ZSM-5, modified in binary system oxide- based Sn (III) and Bi (III). It was defined that the introduction of the binary system oxide-based Sn(III) and Bi (III) into the basic zeolite results in the 2-fold increase of its catalytic activity.High-octane gasoline converted from straight-run benzene is characterized by a low benzol content in comparison to the high-octane benzenes produced during the catalytic reforming

  18. Toward Meaningful Outcomes in Teaching Conversation and Greeting Skills with Individuals with Autism Spectrum Disorder

    Science.gov (United States)

    Hood, Stephanie A.; Luczynski, Kevin C.; Mitteer, Daniel R.

    2017-01-01

    We identified greeting and conversation deficits based on a parent interview and semistructured direct assessment for one child and two adolescents with autism spectrum disorder. We taught the greeting and conversation skills using behavioral skills training and within-session corrective feedback. A multiple baseline across conversation and…

  19. Glycoform-independent prion conversion by highly efficient, cell-based, protein misfolding cyclic amplification

    OpenAIRE

    Moudjou, Mohammed; Chapuis, J?r?me; Mekrouti, M?riem; Reine, Fabienne; Herzog, Laetitia; Sibille, Pierre; Laude, Hubert; Vilette, Didier; Andr?oletti, Olivier; Rezaei, Human; Dron, Michel; B?ringue, Vincent

    2016-01-01

    Prions are formed of misfolded assemblies (PrPSc) of the variably N-glycosylated cellular prion protein (PrPC). In infected species, prions replicate by seeding the conversion and polymerization of host PrPC. Distinct prion strains can be recognized, exhibiting defined PrPSc biochemical properties such as the glycotype and specific biological traits. While strain information is encoded within the conformation of PrPSc assemblies, the storage of the structural information and the molecular req...

  20. Electrical energy conversion and transport an interactive computer-based approach

    CERN Document Server

    Karady, George G

    2013-01-01

    Provides relevant material for engineering students and practicing engineers who want to learn the basics of electrical power transmission, generation, and usage This Second Edition of Electrical Energy Conversion and Transport is thoroughly updated to address the recent environmental effects of electric power generation and transmission, which have become more important in conjunction with the deregulation of the industry. The maintenance and development of the electrical energy generation and transport industry requires well-trained engineers who are able to use mode

  1. Analysis on Energy Conversion of Screw Centrifugal Pump in Impeller Domain Based on Profile Lines

    Directory of Open Access Journals (Sweden)

    Hui Quan

    2013-01-01

    Full Text Available In order to study the power capability of impeller and energy conversion mechanism of screw centrifugal pump, the methods of theoretical analysis and numerical simulation by computational fluid dynamics theory (CFD were adopted, specifically discussing the conditions of internal flow such as velocity, pressure, and concentration. When the medium is sand-water two-phase flow and dividing the rim of the lines and wheel lines of screw centrifugal pump to segments to analyze energy conversion capabilities which along the impeller profile lines with the dynamic head and hydrostatic head changer, the results show that the energy of fluid of the screw centrifugal pump is provided by helical segment, and the helical segment of the front of the impeller has played the role of multilevel increasing energy; the sand-water two phases move at different speeds because the different force field and the impeller propeller and centrifugal effect. As liquid phase is the primary phase, the energy conversion is mainly up to the change of liquid energy, the solid phase flows under the wrapped action of liquid, and solid energy is carried out through liquid indirectly.

  2. Conversion chimique du gaz naturel Chemical Conversion of Natural Gas

    Directory of Open Access Journals (Sweden)

    Chaumette P.

    2006-11-01

    Full Text Available Dans cet article sont passés en revue les travaux de recherche et développement et les procédés existants dans le domaine de la conversion chimique du gaz naturel. Les deux voies possibles, conversion directe du méthane et conversion indirecte, via le gaz de synthèse, sont présentées. Tant la préparation d'hydrocarbures utilisables comme carburants, que celle des composés de bases pour la pétrochimie ou la chimie sont évoquées. L'accent est mis sur l'étape clé du développement de chaque procédé qui, selon le produit visé, consiste en la mise au point d'un nouveau système catalytique, en un changement de la technologie du réacteur, ou en la mise au point d'une section fractionnement moins complexe. This article reviews the research and development work and the existing processes in the area of chemical conversion of natural gas. The two possible methods, direct conversion of methane and indirect conversion via synthesis gas, are discussed. The preparation of hydrocarbons that can be used as fuels and the production of building blocks for the petrochemical and chemical industries are both dealt with. The accent is placed on the key step in developing each process. Depending on the target product, this key step consists in working out a new catalytic system, changing reactor technology or engineering a less complex fractionation section.

  3. Upgrading versus reforming: an energy and exergy analysis of two Solid Oxide Fuel Cell-based systems for a convenient biogas-to-electricity conversion

    International Nuclear Information System (INIS)

    Baldinelli, A.; Barelli, L.; Bidini, G.

    2017-01-01

    Highlights: • Biogas-to-electricity conversion through Solid Oxide Fuel Cell is investigated. • Two solutions are compared for biogas-to-electricity conversion. • Direct feeding by partially upgraded biogas meets with fuel cell long operation. • Best energy and exergy performances are obtained with an innovative system-design. • A sensitivity analysis on the process parameters determines its convenience margin. - Abstract: Aiming at designing biogas-to-electricity advanced systems, Solid Oxide Fuel Cells are promising candidates. They benefit from scalability on plant sizes that suit anaerobic digesters potentialities. For biogas-Solid Oxide Fuel Cells applications, the implementation of an external pre-reformer is usually considered. However, the possibility to perform direct fuel feeding to the Solid Oxide Fuel Cell offers new opportunities towards the realization of lean systems, which are competitive especially on small-scale installations (i.e. on-farm biogas-to-electricity conversion). In this frame, scientific literature is rather poor and, to cover this gap, system simulations are called for two reasons: first, to demonstrate the potential efficiency gain of new concepts; second, to provide a meaningful support for long-term experimental investigation on Solid Oxide Fuel Cells operated upon direct feeding of unreformed biogas. For that, the current study compares two system designs for biogas utilization into Solid Oxide Fuel Cells. The conventional one realizes biogas steam reforming prior the fuel cell, while the novel concept is based on direct feeding of partially upgraded biogas by means of carbon dioxide-separation membranes. As main outcome of the study, the system equipped with carbon dioxide-separation membranes achieves better performances than its conventional competitor does, scoring 51.1% energy efficiency and 52.3% exergy efficiency (compared to 37.2% and 38.6% respectively exhibited by the reformer-based system). Because of the lack

  4. Conversion of biliverdin to bilirubin by biliverdin reductase contributes to endothelial cell protection by heme oxygenase-1-evidence for direct and indirect antioxidant actions of bilirubin.

    Science.gov (United States)

    Jansen, Thomas; Hortmann, Marcus; Oelze, Matthias; Opitz, Benjamin; Steven, Sebastian; Schell, Richard; Knorr, Maike; Karbach, Susanne; Schuhmacher, Swenja; Wenzel, Philip; Münzel, Thomas; Daiber, Andreas

    2010-08-01

    Heme oxygenase-1 (HO-1) is highly protective in various pathophysiological states such as cardiovascular and neurodegenerative diseases. HO-1-derived bilirubin is an efficient scavenger of reactive oxygen and nitrogen species (RONS). It remains to determine whether conversion of biliverdin to bilirubin is an essential step for HO-1-conferred protection of endothelial cells. RONS scavenging activities of biliverdin versus bilirubin were assessed by different RONS generating systems and detection techniques. We also silenced the biliverdin reductase (BVR) or HO-1 gene in cultured primary human endothelial cells (HUVECs) and measured the effect on RONS formation upon stimulation with lipopolysaccharide (LPS). In addition, effects of bilirubin and biliverdin on expression of GTP-cyclohydrolase were assessed in an endothelial cell line (EA.hy 926). HO-1- and BVR-silenced cells have increased levels of oxidative stress and bilirubin but not biliverdin increased expression of the protective protein GTP-cyclohydrolase. Moreover, protection by hemin-induced HO-1 expression or biliverdin-triggered bilirubin formation was impaired upon silencing of the HO-1 or BVR gene, respectively. Since bilirubin significantly scavenged RONS but chronic treatment was even more protective our observations support direct and indirect antioxidant properties of BVR and bilirubin and an important role for BVR and bilirubin in HO-1 conferred protection of endothelial cells.

  5. Mouse Mammary Tumor Virus Promoter-Containing Retroviral Promoter Conversion Vectors for Gene-Directed Enzyme Prodrug Therapy are Functional in Vitro and in Vivo

    Directory of Open Access Journals (Sweden)

    Reinhard Klein

    2008-01-01

    Full Text Available Gene directed-enzyme prodrug therapy (GDEPT is an approach for sensitization of tumor cells to an enzymatically activated, otherwise nontoxic, prodrug. Cytochrome P450 2B1 (CYP2B1 metabolizes the prodrugs cyclophosphamide (CPA and ifosfamide (IFA to produce the cytotoxic substances phosphoramide mustard and isophosphoramide mustard as well as the byproduct acrolein. We have constructed a retroviral promoter conversion (ProCon vector for breast cancer GDEPT. The vector allows expression of CYP2B1 from the mouse mammary tumor virus (MMTV promoter known to be active in the mammary glands of transgenic animals. It is anticipated to be used for the generation of encapsulated viral vector producing cells which, when placed inside or close to a tumor, will act as suppliers of the therapeutic CYP2B1 protein as well as of the therapeutic vector itself. The generated vector was effectively packaged by virus producing cells and allowed the production of high levels of enzymatically active CYP2B1 in infected cells which sensitized them to killing upon treatment with both IFA and CPA. Determination of the respective IC50 values demonstrated that the effective IFA dose was reduced by sixteen folds. Infection efficiencies in vivo were determined using a reporter gene-bearing vector in a mammary cancer cell-derived xenograft tumor mouse model.

  6. The Usefulness of Three-Dimensional Angiography with a Flat Panel Detector of Direct Conversion Type in a Transcatheter Arterial Chemoembolization Procedure for Hepatocellular Carcinoma: Initial Experience

    International Nuclear Information System (INIS)

    Kakeda, Shingo; Korogi, Yukunori; Hatakeyama, Yoshihisa; Ohnari, Norihiro; Oda, Nobuhiro; Nishino, Kazuyoshi; Miyamoto, Wataru

    2008-01-01

    The purpose of this study was to assess the usefulness of a three-dimensional (3D) angiography system using a flat panel detector of direct conversion type in treatments with subsegmental transcatheter arterial chemoembolization (TACE) for hepatocellular carcinomas (HCCs). Thirty-six consecutive patients who underwent hepatic angiography were prospectively examined. First, two radiologists evaluated the degree of visualization of the peripheral branches of the hepatic arteries on 3D digital subtraction angiography (DSA). Then the radiologists evaluated the visualization of tumor staining and feeding arteries in 25 patients (30 HCCs) who underwent subsegmental TACE. The two radiologists who performed the TACE assessed whether the additional information provided by 3D DSA was useful for treatments. In 34 (94.4%) of 36 patients, the subsegmental branches of the hepatic arteries were sufficiently visualized. The feeding arteries of HCCs were sufficiently visualized in 28 (93%) of 30 HCCs, whereas tumor stains were sufficiently visualized in 18 (60%). Maximum intensity projection images were significantly superior to volume recording images for visualization of the tumor staining and feeding arteries of HCCs. In 27 (90%) of 30 HCCs, 3D DSA provided additional useful information for subsegmental TACE. The high-quality 3D DSA with flat panel detector angiography system provided a precise vascular road map, which was useful for performing subsegmental TACE .of HCCs

  7. Experimental Test and Simulations on a Linear Generator-Based Prototype of a Wave Energy Conversion System Designed with a Reliability-Oriented Approach

    Directory of Open Access Journals (Sweden)

    Valeria Boscaino

    2017-01-01

    Full Text Available In this paper, we propose a reliability-oriented design of a linear generator-based prototype of a wave energy conversion (WEC, useful for the production of hydrogen in a sheltered water area like Mediterranean Sea. The hydrogen production has been confirmed by a lot of experimental testing and simulations. The system design is aimed to enhance the robustness and reliability and is based on an analysis of the main WEC failures reported in literature. The results of this analysis led to some improvements that are applied to a WEC system prototype for hydrogen production and storage. The proposed WEC system includes the electrical linear generator, the power conversion system, and a sea-water electrolyzer. A modular architecture is conceived to provide ease of extension of the power capability of the marine plant. The experimental results developed on the permanent magnet linear electric generator have allowed identification of the stator winding typology and, consequently, ability to size the power electronics system. The produced hydrogen has supplied a low-power fuel cell stack directly connected to the hydrogen output from the electrolyzer. The small-scale prototype is designed to be installed, in the near future, into the Mediterranean Sea. As shown by experimental and simulation results, the small-scale prototype is suitable for hydrogen production and storage from sea water in this area.

  8. Mobile Agent-Based Directed Diffusion in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Kwon Taekyoung

    2007-01-01

    Full Text Available In the environments where the source nodes are close to one another and generate a lot of sensory data traffic with redundancy, transmitting all sensory data by individual nodes not only wastes the scarce wireless bandwidth, but also consumes a lot of battery energy. Instead of each source node sending sensory data to its sink for aggregation (the so-called client/server computing, Qi et al. in 2003 proposed a mobile agent (MA-based distributed sensor network (MADSN for collaborative signal and information processing, which considerably reduces the sensory data traffic and query latency as well. However, MADSN is based on the assumption that the operation of mobile agent is only carried out within one hop in a clustering-based architecture. This paper considers MA in multihop environments and adopts directed diffusion (DD to dispatch MA. The gradient in DD gives a hint to efficiently forward the MA among target sensors. The mobile agent paradigm in combination with the DD framework is dubbed mobile agent-based directed diffusion (MADD. With appropriate parameters set, extensive simulation shows that MADD exhibits better performance than original DD (in the client/server paradigm in terms of packet delivery ratio, energy consumption, and end-to-end delivery latency.

  9. The detection of transient directional couplings based on phase synchronization

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, T; Fell, J; Lehnertz, K, E-mail: twagner@uni-bonn.d [Department of Epileptology, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn (Germany)

    2010-05-15

    We extend recent approaches based on the concept of phase synchronization to enable the time-resolved investigation of directional relationships between coupled dynamical systems from short and transient noisy time series. For our approach, we consider an observed ensemble of a sufficiently large number of time series as multiple realizations of a process. We derive an index that quantifies the direction of transient interactions and assess its statistical significance using surrogate techniques. Analysing time series from noisy and chaotic systems, we demonstrate numerically the applicability and limitations of our approach. Our findings from an exemplary application to event-related brain activities underline the importance of our method for improving knowledge about the mechanisms underlying memory formation in humans.

  10. The detection of transient directional couplings based on phase synchronization

    International Nuclear Information System (INIS)

    Wagner, T; Fell, J; Lehnertz, K

    2010-01-01

    We extend recent approaches based on the concept of phase synchronization to enable the time-resolved investigation of directional relationships between coupled dynamical systems from short and transient noisy time series. For our approach, we consider an observed ensemble of a sufficiently large number of time series as multiple realizations of a process. We derive an index that quantifies the direction of transient interactions and assess its statistical significance using surrogate techniques. Analysing time series from noisy and chaotic systems, we demonstrate numerically the applicability and limitations of our approach. Our findings from an exemplary application to event-related brain activities underline the importance of our method for improving knowledge about the mechanisms underlying memory formation in humans.

  11. The detection of transient directional couplings based on phase synchronization

    Science.gov (United States)

    Wagner, T.; Fell, J.; Lehnertz, K.

    2010-05-01

    We extend recent approaches based on the concept of phase synchronization to enable the time-resolved investigation of directional relationships between coupled dynamical systems from short and transient noisy time series. For our approach, we consider an observed ensemble of a sufficiently large number of time series as multiple realizations of a process. We derive an index that quantifies the direction of transient interactions and assess its statistical significance using surrogate techniques. Analysing time series from noisy and chaotic systems, we demonstrate numerically the applicability and limitations of our approach. Our findings from an exemplary application to event-related brain activities underline the importance of our method for improving knowledge about the mechanisms underlying memory formation in humans.

  12. Graphene based integrated tandem supercapacitors fabricated directly on separators

    KAUST Repository

    Chen, Wei

    2015-04-09

    It is of great importance to fabricate integrated supercapacitors with extended operation voltages as high energy density storage devices. In this work, we develop a novel direct electrode deposition on separator (DEDS) process to fabricate graphene based integrated tandem supercapacitors for the first time. The DEDS process generates compact graphene-polyaniline electrodes directly on the separators to form integrated supercapacitors. The integrated graphene-polyaniline tandem supercapacitors demonstrate ultrahigh volumetric energy density of 52.5 Wh L^(−1) at power density of 6037 W L^(−1) and excellent gravimetric energy density of 26.1 Wh kg^(−1) at power density of 3002 W kg^(−1) with outstanding electrochemical stability for over 10000 cycles. This study show great promises for the future development of integrated energy storage devices.

  13. TU-F-18C-02: Increasing Amorphous Selenium Thickness in Direct Conversion Flat-Panel Imagers for Contrast-Enhanced Dual-Energy Breast Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Scaduto, DA; Hu, Y-H; Zhao, W [Stony Brook University, Stony Brook, NY (United States)

    2014-06-15

    Purpose: Contrast-enhanced (CE) breast imaging using iodinated contrast agents requires imaging with x-ray spectra at energies greater than those used in mammography. Optimizing amorphous selenium (a-Se) flat panel imagers (FPI) for this higher energy range may increase lesion conspicuity. Methods: We compare imaging performance of a conventional FPI with 200 μm a-Se conversion layer to a prototype FPI with 300 μm a-Se layer. Both detectors are evaluated in a Siemens MAMMOMAT Inspiration prototype digital breast tomosynthesis (DBT) system using low-energy (W/Rh 28 kVp) and high-energy (W/Cu 49 kVp) x-ray spectra. Detectability of iodinated lesions in dual-energy images is evaluated using an iodine contrast phantom. Effects of beam obliquity are investigated in projection and reconstructed images using different reconstruction methods. The ideal observer signal-to-noise ratio is used as a figure-of-merit to predict the optimal a-Se thickness for CE lesion detectability without compromising conventional full-field digital mammography (FFDM) and DBT performance. Results: Increasing a-Se thickness from 200 μm to 300 μm preserves imaging performance at typical mammographic energies (e.g. W/Rh 28 kVp), and improves the detective quantum efficiency (DQE) for high energy (W/Cu 49 kVp) by 30%. While the more penetrating high-energy x-ray photons increase geometric blur due to beam obliquity in the FPI with thicker a-Se layer, the effect on lesion detectability in FBP reconstructions is negligible due to the reconstruction filters employed. Ideal observer SNR for CE objects shows improvements in in-plane detectability with increasing a-Se thicknesses, though small lesion detectability begins to degrade in oblique projections for a-Se thickness above 500 μm. Conclusion: Increasing a-Se thickness in direct conversion FPI from 200 μm to 300 μm improves lesion detectability in CE breast imaging with virtually no cost to conventional FFDM and DBT. This work was partially

  14. Wavelet based transformer protection using high frequency power directional signals

    Energy Technology Data Exchange (ETDEWEB)

    Valsan, Simi P.; Swarup, K.S. [Department of Electrical Engineering, Indian Institute of Technology Madras (India)

    2008-04-15

    This paper proposes a novel wavelet transform based relaying scheme for power transformer protection. The relay logic consists of two parts: disturbance detection based on first level high frequency details of the voltage signals only and fault discrimination using a power based directional signal derived from the first level high frequency details of both voltage and current signals. The logic is deterministic, computationally efficient, fast, secure and highly reliable. The operating time is 6 ms, about 1/3rd of power frequency cycle (20 ms). The scheme uses only the sign of the directional signals, rather than the difference in their magnitudes, hence it can work reliably in the presence of transformer tap variation, fault resistance and CT saturation. The validity of the proposed logic was exhaustively tested by simulating various types of internal and external faults, energization conditions and load variations on a 132 kV system modeled in ATP/EMTP with a 31.5 MVA, 132/33 kV, Y-{delta} transformer. The proposed logic was able to correctly discriminate between internal faults, external faults and non-fault disturbances for all the 880 test cases. (author)

  15. Roughness-Based Superhydrophobic Surfaces: Fundamentals and Future Directions

    Science.gov (United States)

    Patankar, Neelesh

    2011-11-01

    Superhydrophobicity of rough surfaces has attracted global interest through the past decade. There are naturally occurring instances of such surfaces, e.g., lotus leaves, which led to the popular term ``lotus effect.'' Numerous applications in wide ranging areas such as drag reduction, self-cleaning, heat exchangers, energy conversion, condensation, anti-icing, textile, desalination, etc., are being explored by researchers worldwide. The signature configuration for superhydrophobicity has been ``bead-like'' drops on rough surfaces that roll-off easily. This becomes possible if the liquid does not impale the roughness grooves, and if the contact angle hysteresis is low. Finding appropriate surface roughness is therefore necessary. A thermodynamic framework to enable analysis of this problem will be presented. It will be noted that the success of rough superhydrophobic substrates relies on the presence of gas pockets in the roughness grooves underneath the liquid. These gas pockets could be those of air from the surrounding environment. Current design strategies rely on the availability of air. However, if the rough substrates are fully submerged in the liquid then the trapped air in the roughness grooves may not be sustained. A design approach based on sustaining a vapor phase of the liquid itself in the roughness grooves, instead of relying on the presence of air, will be presented. The resulting surfaces, referred to as vapor stabilizing substrates, are deemed to be robust against wetting transition even if no air is present. Applications of this approach include low drag surfaces, nucleate boiling at dramatically low superheats, among others. The concept can be generalized to other transitions on the phase diagram, thus enabling the design of rough surfaces for phase manipulation in general.

  16. High Temperature Fusion Reactor Cooling Using Brayton Cycle Based Partial Energy Conversion

    Science.gov (United States)

    Juhasz, Albert J.; Sawicki, Jerzy T.

    2003-01-01

    For some future space power systems using high temperature nuclear heat sources most of the output energy will be used in other than electrical form, and only a fraction of the total thermal energy generated will need to be converted to electrical work. The paper describes the conceptual design of such a partial energy conversion system, consisting of a high temperature fusion reactor operating in series with a high temperature radiator and in parallel with dual closed cycle gas turbine (CCGT) power systems, also referred to as closed Brayton cycle (CBC) systems, which are supplied with a fraction of the reactor thermal energy for conversion to electric power. Most of the fusion reactor's output is in the form of charged plasma which is expanded through a magnetic nozzle of the interplanetary propulsion system. Reactor heat energy is ducted to the high temperature series radiator utilizing the electric power generated to drive a helium gas circulation fan. In addition to discussing the thermodynamic aspects of the system design the authors include a brief overview of the gas turbine and fan rotor-dynamics and proposed bearing support technology along with performance characteristics of the three phase AC electric power generator and fan drive motor.

  17. Error Made in Conversation by Indonesian Learners Learning English Based on Syntax and Exchanging Information

    Directory of Open Access Journals (Sweden)

    Melania Wiannastiti

    2014-10-01

    Full Text Available In learning a second language or foreign language (L2, learners should master the competences. Normally, L2 learners first should master the linguistic competence which includes the mastery of vocabularies, pronunciation, and grammar. The study is to find out the syntax error made by L2 learners in conversation as well as to find out the exchanging information. The data were the recording conversation of Visual Communication Design students first semester of Binus University joining English Entrant. Error analysis was used to analyze the data. There are two points of view to analyze the data: syntax from taxonomy and exchanging information. Taxonomy employs the error in omission, addition, misinformation, and mis-ordering. Exchanging information point of view employs the error in finite element and mood. The result shows that L2 learners made some errors in grammar and exchanging information because they are influenced by the L1. They tend to transfer from L1 to L2 rather than thinking to create the utterances in L2. 

  18. Quadruple multi-wavelength conversion for access network scalability based on cross-phase modulation in an SOA-MZI

    Science.gov (United States)

    Ab-Rahman, Mohammad Syuhaimi; Swedan, Abdulhameed Almabrok

    2017-12-01

    The emergence of new services and data exchange applications has increased the demand for bandwidth among individuals and commercial business users at the access area. Thus, vendors of optical access networks should achieve a high-capacity system. This study demonstrates the performance of an integrated configuration of one to four multi-wavelength conversions at 10 Gb/s based on cross-phase modulation using semiconductor optical amplifier integrated with Mach-Zehnder interferometer. The Opti System simulation tool is used to simulate and demonstrate one to four wavelength conversions using one modulated wavelength and four probes of continuous wave sources. The wavelength converter processes are confirmed through investigation of the input and output characteristics, optical signal-to-noise ratio, conversion efficiency, and extinction ratio of new modulated channels after separation by demultiplexing. The outcomes of the proposed system using single channel indicate that the capacity can increase from 10 Gb/s to 50 Gb/s with a maximum number of access points increasing from 64 to 320 (each point with 156.25 Mb/s bandwidth). The splitting ratio of 1:16 provides each client with 625 Mb/s for the total number of 80 users. The Q-factor and bit error rate curves are investigated to confirm and validate the modified scheme and prove the system performance of the full topology of 25 km with 1/64 splitter. The outcomes are within the acceptable range to provide the system scalability.

  19. Optimization of process factors for self-healing vanadium-based conversion coating on AZ31 magnesium alloy

    International Nuclear Information System (INIS)

    Li, Kun; Liu, Junyao; Lei, Ting; Xiao, Tao

    2015-01-01

    Highlights: • The optimum operating conditions were determined by an orthogonal experiment. • The coating is composed of oxides and hydroxides of V 5+ , V 4+ and Mg(OH) 2 . • The self-healing performance was investigated by cross-cut immersion test. • The vanadia conversion coating provided active corrosion protection to AZ31 alloy. - Abstract: A self-healing vanadium-based conversion coating was prepared on AZ31 magnesium alloy. The optimum operating conditions including vanadia solution concentration, pH and treating temperature for obtaining the best corrosion protective vanadia coatings and improved localized corrosion resistance to the magnesium substrate were determined by an orthogonal experiment design. Surface morphology and composition of the resultant conversion coatings were investigated by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The self-healing behavior of the coating was investigated by cross-cut immersion test and electrochemical impedance spectroscopy (EIS) measurements in 3.5% NaCl solution.

  20. Directing the public to evidence-based online content.

    Science.gov (United States)

    Cooper, Crystale Purvis; Gelb, Cynthia A; Vaughn, Alexandra N; Smuland, Jenny; Hughes, Alexandra G; Hawkins, Nikki A

    2015-04-01

    To direct online users searching for gynecologic cancer information to accurate content, the Centers for Disease Control and Prevention's (CDC) 'Inside Knowledge: Get the Facts About Gynecologic Cancer' campaign sponsored search engine advertisements in English and Spanish. From June 2012 to August 2013, advertisements appeared when US Google users entered search terms related to gynecologic cancer. Users who clicked on the advertisements were directed to relevant content on the CDC website. Compared with the 3 months before the initiative (March-May 2012), visits to the CDC web pages linked to the advertisements were 26 times higher after the initiative began (June-August 2012) (padvertisements were supplemented with promotion on television and additional websites (September 2012-August 2013) (padvertisements can direct users to evidence-based content at a highly teachable moment--when they are seeking relevant information. © The Author 2014. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Fabric-based alkaline direct formate microfluidic fuel cells.

    Science.gov (United States)

    Domalaon, Kryls; Tang, Catherine; Mendez, Alex; Bernal, Franky; Purohit, Krutarth; Pham, Linda; Haan, John; Gomez, Frank A

    2017-04-01

    Fabric-based microfluidic fuel cells (MFCs) serve as a novel, cost-efficient alternative to traditional FCs and batteries, since fluids naturally travel across fabric via capillary action, eliminating the need for an external pump and lowering production and operation costs. Building on previous research with Y-shaped paper-based MFCs, fabric-based MFCs mitigate fragility and durability issues caused by long periods of fuel immersion. In this study, we describe a microfluidic fabric-based direct formate fuel cell, with 5 M potassium formate and 30% hydrogen peroxide as the anode fuel and cathode oxidant, respectively. Using a two-strip, stacked design, the optimized parameters include the type of encasement, the barrier, and the fabric type. Surface contact of the fabric and laminate sheet expedited flow and respective chemical reactions. The maximum current (22.83 mA/cm 2 ) and power (4.40 mW/cm 2 ) densities achieved with a 65% cotton/35% polyester blend material are a respective 8.7% and 32% higher than previous studies with Y-shaped paper-based MFCs. In series configuration, the MFCs generate sufficient energy to power a handheld calculator, a thermometer, and a spectrum of light-emitting diodes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Bio-based alkyds by direct enzymatic bulk polymerization

    DEFF Research Database (Denmark)

    Nguyen, Hiep Dinh

    materials before a 100% bio-based alkyd paint can be realized. In this project an enzyme catalyzed bulk polymerization method for direct production of alkyds has been developed. The objective has been to make it possible to produce binders at much lower temperatures as well as to achieve a higher degree....... Bio-based alkyds prepared from a combination of glycerol, and tall oil fatty acids, and azelaic acid by enzymatic polymerization show improved hydrophobicity and lower glass transition temperatures compared to an alkyd prepared from the same raw materials by a classical boiling method. The enzymatic...... working on the coupling between reinforcement agents and the binder in alkyd coatings. For this purpose, two different types of silica particles were modified with rape seed oil fatty acids or tall oil fatty acids (TOFA-silica), respectively. Tests of TOFA-silica particles have demonstrated...

  3. Optimization of a motor learning attention-directing strategy based on an individual's motor imagery ability.

    Science.gov (United States)

    Sakurada, Takeshi; Hirai, Masahiro; Watanabe, Eiju

    2016-01-01

    Motor learning performance has been shown to be affected by various cognitive factors such as the focus of attention and motor imagery ability. Most previous studies on motor learning have shown that directing the attention of participants externally, such as on the outcome of an assigned body movement, can be more effective than directing their attention internally, such as on body movement itself. However, to the best of our knowledge, no findings have been reported on the effect of the focus of attention selected according to the motor imagery ability of an individual on motor learning performance. We measured individual motor imagery ability assessed by the Movement Imagery Questionnaire and classified the participants into kinesthetic-dominant (n = 12) and visual-dominant (n = 8) groups based on the questionnaire score. Subsequently, the participants performed a motor learning task such as tracing a trajectory using visuomotor rotation. When the participants were required to direct their attention internally, the after-effects of the learning task in the kinesthetic-dominant group were significantly greater than those in the visual-dominant group. Conversely, when the participants were required to direct their attention externally, the after-effects of the visual-dominant group were significantly greater than those of the kinesthetic-dominant group. Furthermore, we found a significant positive correlation between the size of after-effects and the modality-dominance of motor imagery. These results suggest that a suitable attention strategy based on the intrinsic motor imagery ability of an individual can improve performance during motor learning tasks.

  4. Energy conversion alternatives study

    Science.gov (United States)

    Shure, L. T.

    1979-01-01

    Comparison of coal based energy systems is given. Study identifies and compares various advanced energy conversion systems using coal or coal derived fuels for baselaoad electric power generation. Energy Conversion Alternatives Study (ECAS) reports provede government, industry, and general public with technically consistent basis for comparison of system's options of interest for fossilfired electric-utility application.

  5. Alkoxide-based precursors for direct electrospinning of alumina fibers

    Science.gov (United States)

    Maneeratana, Vasana

    The vision for space exploration in 2004 reinvigorated excitement that was engendered during the 1960's space race. Looking to assist NASA's agency wide mission to develop new technologies to enhance space travel, it is the ultimate goal of this work to support future missions with a hand-held electrospinning apparatus to instantaneously repair existing crucial ceramic fiber structures, such as spacesuits, insulative foams, and tiles. In this research, a new type of precursor is designed based from aluminum alkoxide-based precursors, since alumina serves as a base material for a majority of high-temperature applications. The structure-processing behavior of these precursors is subsequently studied. New precursors of aluminum alkoxides were prepared by modifying solutions; as a result various types of structures were produced, ranging from continuous hollow fibers, continuous solid fibers, or hollow particles. Direct electrospinning with these alkoxide-based precursors yielded an average of 1.9 g/hr of Al2O3, compared to literature with the highest theoretical yield calculated to be 0.68 g/hr. Further exploration of electrospinning parameters found that flow rate directly related to exposure times; therefore fibers were produced in the atmosphere through hydrolysis/condensation with simultaneous solvent evaporation. Furthermore other processing parameters, including the effect of the microstructure due to processing in an electric field were studied. It was found that electrospinning promotes the reaction of the alkoxide, which thereby reduces trapped solvents. As a result of firing schedules, the fibers' hollow features were preserved, and precursors with volatile species resulted in near net shaped fibers. At low firing temperatures, specific surface areas in the range of 330-345 m 2/g were found electrospun fibers. Additionally modified precursors lowered alpha transitions of fibers down to ˜900°C.

  6. Towards efficient solar-to-hydrogen conversion: Fundamentals and recent progress in copper-based chalcogenide photocathodes

    Directory of Open Access Journals (Sweden)

    Chen Yubin

    2016-09-01

    Full Text Available Photoelectrochemical (PEC water splitting for hydrogen generation has been considered as a promising route to convert and store solar energy into chemical fuels. In terms of its large-scale application, seeking semiconductor photoelectrodes with high efficiency and good stability should be essential. Although an enormous number of materials have been explored for solar water splitting in the last several decades, challenges still remain for the practical application. P-type copper-based chalcogenides, such as Cu(In, GaSe2 and Cu2ZnSnS4, have shown impressive performance in photovoltaics due to narrow bandgaps, high absorption coefficients, and good carrier transport properties. The obtained high efficiencies in photovoltaics have promoted the utilization of these materials into the field of PEC water splitting. A comprehensive review on copper-based chalcogenides for solar-to-hydrogen conversion would help advance the research in this expanding area. This review will cover the physicochemical properties of copper-based chalco-genides, developments of various photocathodes, strategies to enhance the PEC activity and stability, introductions of tandem PEC cells, and finally, prospects on their potential for the practical solar-to-hydrogen conversion. We believe this review article can provide some insights of fundamentals and applications of copper-based chalco-genide thin films for PEC water splitting.

  7. Conversion technique from paper-based seismic profiles to SEG-Y degital data, provided by free softwares

    Science.gov (United States)

    Tuzino, Taqumi

    This article introduces a conversion method from paper-based seismic profiles to SEG-Y formatted degital data. This method employs two free software, NetPBM and Seismic Unix which work on Unix-like OS. The principle is 1) scanning paper-based profiles to obtain pixel images conposed of 8 bit charactor, 2) conversion of trace data format from character to floating and 3) paste of SEG-Y header to floating trace data. Paper-based profiles drown by line scan recorder were successfully converted to trace-by-pixel SEG-Y data. Paper based wiggle profiles were converted firstly to trace-by-pixel SEG-Y data, and then to trace-by-trace SEG-Y data, by using horizontal trace sum of trace-by-pixel data. Quality of these data was examined and proofed that they are tolerable to be used, though they have restriction of paper. SEG-Y convertied data would provide additional analyses; deconvolution, migration, seismic attribute analyses, and would be ready for interpretation softwares.

  8. High efficiency chemical energy conversion system based on a methane catalytic decomposition reaction and two fuel cells: Part I. Process modeling and validation

    Science.gov (United States)

    Liu, Qinghua; Tian, Ye; Li, Hongjiao; Jia, Lijun; Xia, Chun; Thompson, Levi T.; Li, Yongdan

    A highly efficient integrated energy conversion system is built based on a methane catalytic decomposition reactor (MCDR) together with a direct carbon fuel cell (DCFC) and an internal reforming solid oxide fuel cell (IRSOFC). In the MCDR, methane is decomposed to pure carbon and hydrogen. Carbon is used as the fuel of DCFC to generate power and produce pure carbon dioxide. The hydrogen and unconverted methane are used as the fuel in the IRSOFC. A gas turbine cycle is also used to produce more power output from the thermal energy generated in the IRSOFC. The output performance and efficiency of both the DCFC and IRSOFC are investigated and compared by development of exact models of them. It is found that this system has a unique loading flexibility due to the good high-loading property of DCFC and the good low loading property of IRSOFC. The effects of temperature, pressure, current densities, and methane conversion on the performance of the fuel cells and the system are discussed. The CO 2 emission reduction is effective, up to 80%, can be reduced with the proposed system.

  9. Unidirectional transmission based on polarization conversion and excitation of magnetic or surface polaritons

    Directory of Open Access Journals (Sweden)

    Xiaohu Wu

    2017-07-01

    Full Text Available We propose in this work combing a uniaxial crystal slab with a one-dimensional grating to realize unidirectional transmission (UDT. The physical mechanism for the UDT is attributed to polarization conversion with uniaxial crystal slab and excitation of magnetic polaritons (MPs or surface plasmon polaritons (SPPs in the grating region. Numerical simulations were performed by taking hexagonal boron nitride as the uniaxial crystal. The results reveal that UDT can be achieved for both TE and TM waves in the mid-infrared and the optical regions if the grating material is respectively selected as silicon carbide (SiC and silver (Ag with properly chosen values of the structure’s geometric parameters. This work may provide important guidelines for design of novel unidirectional transmission devices.

  10. Conversion of lignin to aromatic-based chemicals (L-chems) and biofuels (L-fuels).

    Science.gov (United States)

    Beauchet, R; Monteil-Rivera, F; Lavoie, J M

    2012-10-01

    Conversion of lignin into chemicals and biofuels was performed using the commercial Kraft lignin, Indulin AT. Lignin was depolymerised in an aqueous alkaline solution using a continuous flow reactor generating four fractions. First is the gas fraction (mainly CO(2)), the second includes methanol, acetic acid and formic acid, thus defined as small organic compounds and third one (up to 19.1 wt.% of lignin) is mostly composed of aromatic monomers. The fourth fraction (45-70 wt.%) contains oligomers (polyaromatic molecules) and modified lignin. Pyrocatechol was the most abundant product at high severities (315°C) with selectivity up to 25.8%. (31)P NMR showed the loss of almost all aliphatic OH groups and apparition of catechol groups during depolymerisation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Permanent Magnet Synchronous Generator Driven Wind Energy Conversion System Based on Parallel Active Power Filter

    Directory of Open Access Journals (Sweden)

    FERDI Brahim

    2014-05-01

    Full Text Available This paper proposes a novel application of the instantaneous P-Q theory in a wind energy conversion system (WECS. The proposed WECS is formed by permanent magnet synchronous generator (PMSG wind turbine system connected to the grid through parallel active power filter (PAPF. PAPF uses the generated wind energy to feed loads connected at the point of common coupling (PPC, compensates current harmonics and injects the excess of this energy into the grid using P-Q theory as control method. To demonstrate the feasibility and the performance of the proposed control scheme, simulation of this wind system has been realized using MATLAB/SIMULINK software. Simulation results show the accuracy and validity of the proposed control scheme for the PMSGPAPF system.

  12. Detection of SNP effects on feed conversion ratio in pigs based on entropy approach

    Directory of Open Access Journals (Sweden)

    Henry Reyer

    2016-09-01

    Full Text Available The objectives of the study were to classify SNPs according to their contribution to the feed conversion ratio and to indicate interactions between the most informative SNPs using entropy analysis. The records of 1296 pigs were included. Two selection criteria for molecular data were applied: call rate 0.95 and minor allele frequency 0.05. After this, 50 951 SNPs were included into the entropy analysis. For each SNP entropy and conditional entropy were estimated. For interaction analyses the most informative SNPs were selected. For each pair of SNPs, the mutual information was assessed. A majority of the loci studied showed relatively small contributions. The most informative SNPs are mainly located on chromosomes: 1, 4, 7, 9 and 14. Whereas important interactions between SNP pairs were detected on chromosomes: 1, 14, 15 and 16. High mutual information was registered for SNPs located nearby.

  13. Semiconductor-Based Photoelectrochemical Conversion of Carbon Dioxide: Stepping Towards Artificial Photosynthesis.

    Science.gov (United States)

    Pang, Hong; Masuda, Takuya; Ye, Jinhua

    2018-01-18

    The photoelectrochemical (PEC) carbon dioxide reduction process stands out as a promising avenue for the conversion of solar energy into chemical feedstocks, among various methods available for carbon dioxide mitigation. Semiconductors derived from cheap and abundant elements are interesting candidates for catalysis. Whether employed as intrinsic semiconductors or hybridized with metallic cocatalysts, biocatalysts, and metal molecular complexes, semiconductor photocathodes exhibit good performance and low overpotential during carbon dioxide reduction. Apart from focusing on carbon dioxide reduction materials and chemistry, PEC cells towards standalone devices that use photohybrid electrodes or solar cells have also been a hot topic in recent research. An overview of the state-of-the-art progress in PEC carbon dioxide reduction is presented and a deep understanding of the catalysts of carbon dioxide reduction is also given. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Graphene-based photovoltaic cells for near-field thermal energy conversion.

    Science.gov (United States)

    Messina, Riccardo; Ben-Abdallah, Philippe

    2013-01-01

    Thermophotovoltaic devices are energy-conversion systems generating an electric current from the thermal photons radiated by a hot body. While their efficiency is limited in far field by the Schockley-Queisser limit, in near field the heat flux transferred to a photovoltaic cell can be largely enhanced because of the contribution of evanescent photons, in particular for a source supporting a surface mode. Unfortunately, in the infrared where these systems operate, the mismatch between the surface-mode frequency and the semiconductor gap reduces drastically the potential of this technology. In this paper we propose a modified thermophotovoltaic device in which the cell is covered by a graphene sheet. By discussing the transmission coefficient and the spectral properties of the flux, we show that both the cell efficiency and the produced current can be enhanced, paving the way to promising developments for the production of electricity from waste heat.

  15. Nanotechnology Based Green Energy Conversion Devices with Multifunctional Materials at Low Temperatures.

    Science.gov (United States)

    Lu, Yuzheng; Afzal, Muhammad; Zhu, Bin; Wang, Baoyuan; Wang, Jun; Xia, Chen

    2017-07-10

    Nanocomposites (integrating the nano and composite technologies) for advanced fuel cells (NANOCOFC) demonstrate the great potential to reduce the operational temperature of solid oxide fuel cell (SOFC) significantly in the low temperature (LT) range 300-600ºC. NANOCOFC has offered the development of multi-functional materials composed of semiconductor and ionic materials to meet the requirements of low temperature solid oxide fuel cell (LTSOFC) and green energy conversion devices with their unique mechanisms. This work reviews the recent developments relevant to the devices and the patents in LTSOFCs from nanotechnology perspectives that reports advances including fabrication methods, material compositions, characterization techniques and cell performances. Finally, the future scope of LTSOFC with nanotechnology and the practical applications are also discussed. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

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

    Science.gov (United States)

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

    2017-02-01

    The environmental impacts with regard to agro-based biofuel production have been associated with the impact of greenhouse gas (GHG) emissions. In this study, field GHG emissions during plantation stage of palm oil-based biofuel production associated with land use changes for oil palm plantation development have been evaluated. Three different sites of different land use changes prior to oil palm plantation were chosen; converted land-use (large and small-scales) and logged-over forest. Field sampling for determination of soil N-mineralisation and soil organic carbon (SOC) was undertaken at the sites according to the age of palm, i.e. 21 years (mature oil palms). The field data were incorporated into the estimation of nitrous oxide (N 2 O) and the resulting CO 2 -eq emissions as well as for estimation of carbon stock changes. Irrespective of the land conversion scenarios, the nitrous oxide emissions were found in the range of 6.47-7.78 kg N 2 O-N/ha resulting in 498-590 kg CO 2 -eq/ha. On the other hand, the conversion of tropical forest into oil palm plantation has resulted in relatively higher GHG emissions (i.e. four times higher and carbon stock reduction by >50%) compared to converted land use (converted rubber plantation) for oil palm development. The conversion from previously rubber plantation into oil palm plantation would increase the carbon savings (20% in increase) thus sustaining the environmental benefits from the palm oil-based biofuel production.

  17. High conversion self-curing sealer based on a novel injectable polyurethane system for root canal filling

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Bin [Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu 610064 (China); Zuo, Yi, E-mail: zoae@scu.edu.cn [Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu 610064 (China); Li, Jidong; Wang, Li [Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu 610064 (China); Tang, Kuangyun [The State Key Laboratory of Oral Diseases and Orthognathic Surgery, Sichuan University West China College of Stomatology, Chengdu 610064 (China); Huang, Di; Du, Jingjing; Luo, Peipei; Li, Yubao [Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu 610064 (China)

    2013-08-01

    Low monomer–polymer conversion is the key factor leading to cytotoxicity for resin-containing restorative materials. This paper provides a new root canal filling system based on self-curing injectable polyurethane which can achieve high conversion in a short time. Traced FTIR spectra show more than 90% NCO group participated in the curing reaction after 4 h, and only about 5% remained after 24 h. The calculated data also testified the curing process supports a third-order reaction, and this efficient and sufficient reaction is postulated to weaken the toxic stimulation. By culturing with L929 murine fibroblasts, the PU sealer is shown to be favorable for cell attachment and proliferation. Then physicochemical properties of the injectable PU-based sealer were evaluated according to the Standard [ISO 6876:2001 (E)] for clinical application. A series of physicochemical properties of PU sealer have been tested comparing with AH Plus and Apexit Plus. And the results present that the self-curing PU sealer could not only match the clinic requirements, but even has better properties than the other two commercial sealers. We expect the high conversion PU sealer has a tremendous potential in the field of root canal filling after further biological evaluation. - Highlights: • A new root canal sealer based on self-curing injectable polyurethane was provided. • More than 90% NCO group reacted after 4h, and only about 5% remained after 24 h. • By culturing with L929 murine fibroblasts, the PU sealer showed perfect cytocompatibility. • Volumetric dilatancy after curing will make the sealer achieve a tight seal.

  18. Success of community-based directly observed anti-tuberculosis treatment in Mongolia.

    Science.gov (United States)

    Dobler, C C; Korver, S; Batbayar, O; Oyuntsetseg, S; Tsolmon, B; Wright, C; Solongo, B; Marais, B J

    2015-06-01

    Many countries restrict access to directly observed therapy (DOT) for tuberculosis (TB) to government health facilities. More innovative approaches are required to reduce non-adherence, improve patient outcomes and limit the risk of selecting drug-resistant strains. We performed a retrospective cohort study in sputum smear-positive patients treated with community-based DOT (home-based DOT or 'lunch' DOT, whereby DOT is provided with a free daily meal once sputum smear conversion has been documented), and conventional clinic-based DOT in Ulaanbaatar, the capital of Mongolia, in 2010-2011. We compared treatment success using community-based home DOT vs. conventional clinic DOT and describe treatment completion rates using lunch DOT. The overall treatment success among new sputum smear-positive TB patients was 85.1% (1505/1768). Patients receiving community DOT had higher cure rates (294/327, 89.9% vs. 1112/1441, 77.2%; aOR 2.66, 95%CI 1.81-3.90) and higher treatment success (306/327, 93.6% vs. 1199/1441, 83.2%; aOR 2.95, 95%CI 1.85-4.71, P Mongolia. It should now be scaled up to be made available for more patients and in all regions of the country.

  19. Multi performance option in direct displacement based design

    Directory of Open Access Journals (Sweden)

    Muljati Ima

    2017-01-01

    Full Text Available Compare to traditional method, direct displacement based design (DDBD offers the more rational design choice due to its compatibility with performance based design which is controlled by the targeted displacement in design. The objectives of this study are: 1 to explore the performance of DDBD for design Level-1, -2 and -3; 2 to determine the most appropriate design level based on material efficiency and damage risk; and 3 to verify the chosen design in order to check its performance under small-, moderate- and severe earthquake. As case study, it uses regular concrete frame structures consists of fourand eight-story with typical plan, located in low- and high-risk seismicity area. The study shows that design Level-2 (repairable damage is the most appropriate choice. Nonlinear time history analysis is run for each case study in order to verify their performance based on parameter: story drift, damage indices, and plastic mechanism. It can be concluded that DDBD performed very well in predicting seismic demand of the observed structures. Design Level-2 can be chosen as the most appropriate design level. Structures are in safe plastic mechanism under all level of seismicity although some plastic hinges formed at some unexpected locations.

  20. Effects of a Conversation-Based Intervention on the Linguistic Skills of Children With Motor Speech Disorders Who Use Augmentative and Alternative Communication.

    Science.gov (United States)

    Soto, Gloria; Clarke, Michael T

    2017-07-12

    This study was conducted to evaluate the effects of a conversation-based intervention on the expressive vocabulary and grammatical skills of children with severe motor speech disorders and expressive language delay who use augmentative and alternative communication. Eight children aged from 8 to 13 years participated in the study. After a baseline period, a conversation-based intervention was provided for each participant, in which they were supported to learn and use linguistic structures essential for the formation of clauses and the grammaticalization of their utterances, such as pronouns, verbs, and bound morphemes, in the context of personally meaningful and scaffolded conversations with trained clinicians. The conversations were videotaped, transcribed, and analyzed using the Systematic Analysis of Language Transcripts (SALT; Miller & Chapman, 1991). Results indicate that participants showed improvements in their use of spontaneous clauses, and a greater use of pronouns, verbs, and bound morphemes. These improvements were sustained and generalized to conversations with familiar partners. The results demonstrate the positive effects of the conversation-based intervention for improving the expressive vocabulary and grammatical skills of children with severe motor speech disorders and expressive language delay who use augmentative and alternative communication. Clinical and theoretical implications of conversation-based interventions are discussed and future research needs are identified. https://doi.org/10.23641/asha.5150113.

  1. A new 3D mesoporous carbon replicated from commercial silica as a catalyst support for direct conversion of cellulose into ethylene glycol.

    Science.gov (United States)

    Zhang, Yanhua; Wang, Aiqin; Zhang, Tao

    2010-02-14

    Tungsten carbide nanoparticles were supported on a new 3D mesoporous carbon replicated from commercial silica and exhibited selectivity as high as 72.9% for the catalytic conversion of cellulose into ethylene glycol.

  2. A novel cell-scale bio-nanogenerator based on electron-ion interaction for fast light power conversion.

    Science.gov (United States)

    Li, Yu-Tao; Tian, He; Zhao, Hai-Ming; Jian, Mu-Qiang; Lv, Yu-Jia; Tian, Ye; Wang, Qian; Yang, Yi; Xiang, Yan; Zhang, Yingying; Ren, Tian-Ling

    2018-01-03

    Natural energy haversting devices serve as an alternative candidate for power supply in many micro-/nano-systems. However, traditional nanogenerators based on piezoelectricity or triboelectric power generation face challenges in terms of biocompatibility and stability in various biological systems. The bacteriorhodopsin (bR) protein in Halobacterium halobium is an ideal biocompatible material for photoelectric conversion. Conventional bR systems based on ion transport or enhanced light absorption layers have a limited light power conversion speed. On the other hand, bR-based biohybrid devices have a great potential for sensitive light power conversion as compared to conventional nanogenerators. Herein, we present a biohybrid nanogenerator made of bR and horizontally aligned-long carbon nanotubes (CNTs) with electron-ion interaction for the first time for sensitive light power conversion. The bR layer serves as the proton pump, whereas CNTs are utilized to enhance the photocurrent; thus, the photocurrent frequency response improves significantly because of the effect of the electron-ion interaction. The photocurrent shows a linear relationship with the intensity of light and can still obtain a stable signal at a light intensity of 0.03 mW cm -2 . With regard to the influence of the light on-off period, the photocurrent initially increases and then decreases with an increase in flickering frequency up to 360 Hz; this can be ascribed to the combinational influence of light switch speed and photocycle decay time. The photocurrent shows highest value (99 nA cm -2 ) at a frequency of about 50 Hz at a light intensity of 0.43 mW cm -2 , which matches well with the frequency standard of the electrical power supply system. Moreover, we found that a higher density of CNTs contributed to improve performance of the nanogenerators. Furthermore, a H + ion releasing model was proposed to interpret the operating mechanism of the biohybrid nanogenerator. The biohybrid nanogenerator

  3. Pollutant forecasting error based on persistence of wind direction

    International Nuclear Information System (INIS)

    Cooper, R.E.

    1978-01-01

    The purpose of this report is to provide a means of estimating the reliability of forecasts of downwind pollutant concentrations from atmospheric puff releases. These forecasts are based on assuming the persistence of wind direction as determined at the time of release. This initial forecast will be used to deploy survey teams, to predict population centers that may be affected, and to estimate the amount of time available for emergency response. Reliability of forecasting is evaluated by developing a cumulative probability distribution of error as a function of lapsed time following an assumed release. The cumulative error is determined by comparing the forecast pollutant concentration with the concentration measured by sampling along the real-time meteorological trajectory. It may be concluded that the assumption of meteorological persistence for emergency response is not very good for periods longer than 3 hours. Even within this period, the possibiity for large error exists due to wind direction shifts. These shifts could affect population areas totally different from those areas first indicated

  4. One-pot conversion of cellulose to ethylene glycol with multifunctional tungsten-based catalysts.

    Science.gov (United States)

    Wang, Aiqin; Zhang, Tao

    2013-07-16

    With diminishing fossil resources and increasing concerns about environmental issues, searching for alternative fuels has gained interest in recent years. Cellulose, as the most abundant nonfood biomass on earth, is a promising renewable feedstock for production of fuels and chemicals. In principle, the ample hydroxyl groups in the structure of cellulose make it an ideal feedstock for the production of industrially important polyols such as ethylene glycol (EG), according to the atom economy rule. However, effectively depolymerizing cellulose under mild conditions presents a challenge, due to the intra- and intermolecular hydrogen bonding network. In addition, control of product selectivity is complicated by the thermal instabilities of cellulose-derived sugars. A one-pot catalytic process that combines hydrolysis of cellulose and hydrogenation/hydrogenolysis of cellulose-derived sugars proves to be an efficient way toward the selective production of polyols from cellulose. In this Account, we describe our efforts toward the one-pot catalytic conversion of cellulose to EG, a typical petroleum-dependent bulk chemical widely applied in the polyester industry whose annual consumption reaches about 20 million metric tons. This reaction opens a novel route for the sustainable production of bulk chemicals from biomass and will greatly decrease the dependence on petroleum resources and the associated CO₂ emission. It has attracted much attention from both industrial and academic societies since we first described the reaction in 2008. The mechanism involves a cascade reaction. First, acid catalyzes the hydrolysis of cellulose to water-soluble oligosaccharides and glucose (R1). Then, oligosaccharides and glucose undergo C-C bond cleavage to form glycolaldehyde with catalysis of tungsten species (R2). Finally, hydrogenation of glycolaldehyde by a transition metal catalyst produces the end product EG (R3). Due to the instabilities of glycolaldehyde and cellulose

  5. Surface Segregation during Directional Solidification of Ni-Base Superalloys

    Science.gov (United States)

    Brewster, G.; Dong, H. B.; Green, N. R.; D'Souza, N.

    2008-02-01

    Some aspects pertaining to the increased microsegregation at the external casting surface during directional solidification of a typical Ni-base superalloy, CMSX 10N, are presented. Increased eutectic coverage was observed at the external surface along the solidification length. This eutectic appears as a thin segregated layer proud of the secondary dendrite arms preventing them from impinging onto the mold wall. The extent of surface eutectic coverage was represented as a fractional measure of the ingot perimeter. Possible mechanisms focusing on the following: (1) interaction between mold and metal, (2) inclination of primary dendrite, and (3) contraction of the dendrite network have been investigated in relation to the observed phenomenon. We deduce that the most likely explanation is associated with the contraction of the dendritic network, which qualitatively accounts both for the observed morphology and the increased eutectic fraction at the external surface of the casting.

  6. High power density reactors based on direct cooled particle beds

    International Nuclear Information System (INIS)

    Powell, J.R.; Horn, F.L.

    1985-01-01

    Reactors based on direct cooled HTGR type particle fuel are described. The small diameter particle fuel is packed between concentric porous cylinders to make annular fuel elements, with the inlet coolant gas flowing inwards. Hot exit gas flows out long the central channel of each element. Because of the very large heat transfer area in the packed beds, power densities in particle bed reactors (PBR's) are extremely high resulting in compact, lightweight systems. Coolant exit temperatures are high, because of the ceramic fuel temperature capabilities, and the reactors can be ramped to full power and temperature very rapidly. PBR systems can generate very high burst power levels using open cycle hydrogen coolant, or high continuous powers using closed cycle helium coolant. PBR technology is described and development requirements assessed. 12 figs

  7. High power density reactors based on direct cooled particle beds

    Science.gov (United States)

    Powell, J. R.; Horn, F. L.

    Reactors based on direct cooled High Temperature Gas Cooled Reactor (HTGR) type particle fuel are described. The small diameter particle fuel is packed between concentric porous cylinders to make annular fuel elements, with the inlet coolant gas flowing inwards. Hot exit gas flows out along the central channel of each element. Because of the very large heat transfer area in the packed beds, power densities in particle bed reactors (PBRs) are extremely high resulting in compact, lightweight systems. Coolant exit temperatures are high, because of the ceramic fuel temperature capabilities, and the reactors can be ramped to full power and temperature very rapidly. PBR systems can generate very high burst power levels using open cycle hydrogen coolant, or high continuous powers using closed cycle helium coolant. PBR technology is described and development requirements assessed.

  8. Direct methanol fuel cell stack based on MEMS technology

    Science.gov (United States)

    Zhang, Yufeng; Tang, Xiaochuan; Yuan, Zhenyu; Liu, Xiaowei

    2008-10-01

    This paper presents a design configuration of silicon-based micro direct methanol fuel cell (DMFC) stack in a planar array. The integrated series connection is oriented in a "flip-flop" configuration with electrical interconnections made by thin-film metal layers that coat the flow channels etched in the silicon substrate. The configuration features small connection space and low contact resistance. The MEMS fabrication process was utilized to fabricate the silicon plates of DMFC stack. This DMFC stack with an active area of 64mm x 11mm was characterized at room temperature and normal atmosphere. Experimental results show that the prototype stack is able to generate an open-circuit voltage of 2.7V and a maximum power density of 2.2mW/cm2, which demonstrate the feasibility of this new DMFC stack configuration.

  9. Directional eye fixation sensor using birefringence-based foveal detection

    Science.gov (United States)

    Gramatikov, Boris I.; Zalloum, Othman H. Y.; Wu, Yi Kai; Hunter, David G.; Guyton, David L.

    2007-04-01

    We recently developed and reported an eye fixation monitor that detects the fovea by its radial orientation of birefringent nerve fibers. The instrument used a four-quadrant photodetector and a normalized difference function to check for a best match between the detector quadrants and the arms of the bow-tie pattern of polarization states surrounding the fovea. This function had a maximum during central fixation but could not tell where the subject was looking relative to the center. We propose a linear transformation to obtain horizontal and vertical eye position coordinates from the four photodetector signals, followed by correction based on a priori calibration information. The method was verified on both a computer model and on human eyes. The major advantage of this new eye-tracking method is that it uses true information coming from the fovea, rather than reflections from other structures, to identify the direction of foveal gaze.

  10. Mirror-based fusion: some possible new directions

    Energy Technology Data Exchange (ETDEWEB)

    Post, R F., LLNL

    1998-07-16

    This paper examines some possible areas for the study of new approaches to fusion research, ones that employ magnetic confinement systems based on open-ended field topology and employing the magnetic mirror principle. In the spirit of encouraging a wider look at possibilities, some unconventional approaches are suggested. These approaches, involving long linear systems having ion injectors and direct converters at their ends, attempt to exploit some inherent advantages of open-ended systems for fusion. The results of analysis, calculations and preliminary cost estimates for long linear systems of this type that utilize the magnetic mirror effect to achieve their operating regimes will be presented. The approaches suggested, when examined in greater depth, may not stand the test of time, but they might encourage thinking in new areas.

  11. Conversion frequence

    International Nuclear Information System (INIS)

    Sauteret, C.

    1987-03-01

    The experimental evidence of short wavelength for laser inertial confinement has strongly increased the interest in high efficiency harmonic conversion of powerful Nd: glass lasers. This work describes our high power harmonic conversion experiments performed using the same laser apparatus for doubling, tripling the three high power 1064 nm P102, OCTAL and PHEBUS lasers. In addition to the understanding the physics of harmonic conversion, this work includes the basic concepts allows us to improve the technique such as non colinear schemes, to extend this method to other frequencies (fourth generation) and to predict some physical limits [fr

  12. The conversion model: A strategic market segmentation system based on customer commitment and potential to change

    Energy Technology Data Exchange (ETDEWEB)

    Ceurvorst, R.W. [Market Facts, Inc., Arlington Heights, IL (United States)

    1994-11-01

    Deregulation of utilities will require providers of electric power to put the issue of competition at the top of their strategic planning agenda. The companies that will flourish in this new competitive environment are those that have strongly committed customers and potential to grow. {open_quotes}Commitment{close_quotes} is the complex psychological bond between a customer and a brand (or choice); it is critical to measure because it is the foundation of loyalty and brand equity. The Conversion Model is an established, validated strategic research tool that measures customer commitment and potential to change. It was designed to help marketers devise strategies to strengthen the commitment of current customers and to acquire new customers. The Model helps companies protect and grow their businesss by first quantifying the commitment of current customers and the potential to convert competitors` customers. Further, the Model provides managers with actionable insights about the demographic, behavioral and attitudinal factors that characterize customers who are secure in their commitment, those who are vulnerable to being lost, the non-customers who can be won over and those who are unavailable.

  13. Life-cycle-assessment of fuel-cells-based landfill-gas energy conversion technologies

    Science.gov (United States)

    Lunghi, P.; Bove, R.; Desideri, U.

    Landfill-gas (LFG) is produced as result of the biological reaction of municipal solid waste (MSW). This gas contains about 50% of methane, therefore it cannot be released into the atmosphere as it is because of its greenhouse effect consequences. The high percentage of methane encouraged researchers to find solutions to recover the related energy content for electric energy production. The most common technologies used at the present time are internal combustion reciprocating engines and gas turbines. High conversion efficiency guaranteed by fuel cells (FCs) enable to enhance the energy recovery process and to reduce emissions to air, such as NO x and CO. In any case, in order to investigate the environmental advantages associated with the electric energy generation using fuel cells, it is imperative to consider the whole "life cycle" of the system, "from cradle-to-grave". In fact, fuel cells are considered to be zero-emission devices, but, for example, emissions associated with their manufacture or for hydrogen production must be considered in order to evaluate all impacts on the environment. In the present work a molten carbonate fuel cell (MCFC) system for LFG recovery is considered and a life cycle assessment (LCA) is conducted for an evaluation of environmental consequences and to provide a guide for further environmental impact reduction.

  14. Application of nitrogen sufficiency conversion strategy for microalgae-based ammonium-rich wastewater treatment.

    Science.gov (United States)

    Wang, Jinghan; Zhou, Wenguang; Yang, Haizhen; Ruan, Roger

    2016-10-01

    Ammonium ([Formula: see text]-N)-rich wastewater, a main cause for eutrophication, can serve as a promising medium for fast microalgae cultivation with efficient [Formula: see text]-N removal. To achieve this goal, a well-controlled three-stage treatment process was developed. Two trophic modes (mixotrophy and heterotrophy) in Stage 1 and Stage 2, with two nitrogen availability conditions (N sufficient and N deprived) in Stage 2, and different [Formula: see text]-N concentrations in Stage 3 were compared to investigate the effects of nitrogen sufficiency conversion on indigenous strain UMN266 for [Formula: see text]-N removal. Results showed that mixotrophic cultures in the first two stages with N deprivation in Stage 2 was the optimum treatment strategy, and higher [Formula: see text]-N concentration in Stage 3 facilitated both microalgal growth and [Formula: see text]-N removal, with average and maximum biomass productivity of 55.3 and 161.0 mg L(-1) d(-1), and corresponding removal rates of 4.2 and 15.0 mg L(-1) d(-1), respectively, superior to previously published results. Observations of intracellular compositions confirmed the optimum treatment strategy, discovering excellent starch accumulating property of strain UMN266 as well. Combination of bioethanol production with the proposed three-stage process using various real wastewater streams at corresponding stages was suggested for future application.

  15. Glycoform-independent prion conversion by highly efficient, cell-based, protein misfolding cyclic amplification

    Science.gov (United States)

    Moudjou, Mohammed; Chapuis, Jérôme; Mekrouti, Mériem; Reine, Fabienne; Herzog, Laetitia; Sibille, Pierre; Laude, Hubert; Vilette, Didier; Andréoletti, Olivier; Rezaei, Human; Dron, Michel; Béringue, Vincent

    2016-01-01

    Prions are formed of misfolded assemblies (PrPSc) of the variably N-glycosylated cellular prion protein (PrPC). In infected species, prions replicate by seeding the conversion and polymerization of host PrPC. Distinct prion strains can be recognized, exhibiting defined PrPSc biochemical properties such as the glycotype and specific biological traits. While strain information is encoded within the conformation of PrPSc assemblies, the storage of the structural information and the molecular requirements for self-perpetuation remain uncertain. Here, we investigated the specific role of PrPC glycosylation status. First, we developed an efficient protein misfolding cyclic amplification method using cells expressing the PrPC species of interest as substrate. Applying the technique to PrPC glycosylation mutants expressing cells revealed that neither PrPC nor PrPSc glycoform stoichiometry was instrumental to PrPSc formation and strainness perpetuation. Our study supports the view that strain properties, including PrPSc glycotype are enciphered within PrPSc structural backbone, not in the attached glycans. PMID:27384922

  16. Carbon dioxide/methanol conversion cycle based on cascade enzymatic reactions supported on superparamagnetic nanoparticles

    Directory of Open Access Journals (Sweden)

    CATERINA G.C. MARQUES NETTO

    2017-10-01

    Full Text Available ABSTRACT The conversion of carbon dioxide into important industrial feedstock is a subject of growing interest in modern society. A possible way to achieve this goal is by carrying out the CO2/methanol cascade reaction, allowing the recycle of CO2 using either chemical catalysts or enzymes. Efficient and selective reactions can be performed by enzymes; however, due to their low stability, immobilization protocols are required to improve their performance. The cascade reaction to reduce carbon dioxide into methanol has been explored by the authors, using, sequentially, alcohol dehydrogenase (ADH, formaldehyde dehydrogenase (FalDH, and formate dehydrogenase (FDH, powered by NAD+/NADH and glutamate dehydrogenase (GDH as the co-enzyme regenerating system. All the enzymes have been immobilized on functionalized magnetite nanoparticles, and their reactions investigated separately in order to establish the best performance conditions. Although the stepwise scheme led to only 2.3% yield of methanol per NADH; in a batch system under CO2 pressure, the combination of the four immobilized enzymes increased the methanol yield by 64 fold. The studies indicated a successful regeneration of NADH in situ, envisaging a real possibility of using immobilized enzymes to perform the cascade CO2-methanol reaction.

  17. Glycoform-independent prion conversion by highly efficient, cell-based, protein misfolding cyclic amplification.

    Science.gov (United States)

    Moudjou, Mohammed; Chapuis, Jérôme; Mekrouti, Mériem; Reine, Fabienne; Herzog, Laetitia; Sibille, Pierre; Laude, Hubert; Vilette, Didier; Andréoletti, Olivier; Rezaei, Human; Dron, Michel; Béringue, Vincent

    2016-07-07

    Prions are formed of misfolded assemblies (PrP(Sc)) of the variably N-glycosylated cellular prion protein (PrP(C)). In infected species, prions replicate by seeding the conversion and polymerization of host PrP(C). Distinct prion strains can be recognized, exhibiting defined PrP(Sc) biochemical properties such as the glycotype and specific biological traits. While strain information is encoded within the conformation of PrP(Sc) assemblies, the storage of the structural information and the molecular requirements for self-perpetuation remain uncertain. Here, we investigated the specific role of PrP(C) glycosylation status. First, we developed an efficient protein misfolding cyclic amplification method using cells expressing the PrP(C) species of interest as substrate. Applying the technique to PrP(C) glycosylation mutants expressing cells revealed that neither PrP(C) nor PrP(Sc) glycoform stoichiometry was instrumental to PrP(Sc) formation and strainness perpetuation. Our study supports the view that strain properties, including PrP(Sc) glycotype are enciphered within PrP(Sc) structural backbone, not in the attached glycans.

  18. Robust fault detection of wind energy conversion systems based on dynamic neural networks.

    Science.gov (United States)

    Talebi, Nasser; Sadrnia, Mohammad Ali; Darabi, Ahmad

    2014-01-01

    Occurrence of faults in wind energy conversion systems (WECSs) is inevitable. In order to detect the occurred faults at the appropriate time, avoid heavy economic losses, ensure safe system operation, prevent damage to adjacent relevant systems, and facilitate timely repair of failed components; a fault detection system (FDS) is required. Recurrent neural networks (RNNs) have gained a noticeable position in FDSs and they have been widely used for modeling of complex dynamical systems. One method for designing an FDS is to prepare a dynamic neural model emulating the normal system behavior. By comparing the outputs of the real system and neural model, incidence of the faults can be identified. In this paper, by utilizing a comprehensive dynamic model which contains both mechanical and electrical components of the WECS, an FDS is suggested using dynamic RNNs. The presented FDS detects faults of the generator's angular velocity sensor, pitch angle sensors, and pitch actuators. Robustness of the FDS is achieved by employing an adaptive threshold. Simulation results show that the proposed scheme is capable to detect the faults shortly and it has very low false and missed alarms rate.

  19. A flexoelectricity effect-based sensor for direct torque measurement

    International Nuclear Information System (INIS)

    Zhang, Shuwen; Xu, Minglong; Liu, Kaiyuan; Shen, Shengping

    2015-01-01

    In this study, a direct torque sensor based on the flexoelectricity generated by un-polarized polyvinylidene fluoride (PVDF) via electromechanical coupling is developed as a novel torque measurement mechanism that does not require external electric power excitation. The sensing method is developed based on the shear strain gradient and the shear flexoelectric response of PVDF. A theoretical analysis is primarily presented for the design of the sensing structure. Then the structure of the PVDF sensing module is discussed and designed. The radius ratio of the sensing module is defined and then discussed according to the load, the strain gradient, the electrode area and the general electric charge output. The finite element method is used to analyze the mechanical properties of the designed PVDF sensing module. Then the theoretical sensitivity of the sensor is predicated as 0.9441 pC Nm −1 . The experiment system setup is developed, and the sensing properties of the measurement mechanism are tested at frequencies of 0.5 Hz, 1 Hz, 1.5 Hz and 2 Hz using identical modules. The measurement range of the designed sensor is 0–1.68 Nm and the average sensitivity is measured as 0.8950 pC Nm −1 . The experimental results agree well with the theoretically predicted results. These results prove that the torque sensing method based on un-polarized PVDF is suitable for measurement of dynamic torque loads with a flexoelectricity-based mechanism. When using this method, external electric power excitation of the sensing module is no longer required. (paper)

  20. A flexoelectricity effect-based sensor for direct torque measurement

    Science.gov (United States)

    Zhang, Shuwen; Xu, Minglong; Liu, Kaiyuan; Shen, Shengping

    2015-12-01

    In this study, a direct torque sensor based on the flexoelectricity generated by un-polarized polyvinylidene fluoride (PVDF) via electromechanical coupling is developed as a novel torque measurement mechanism that does not require external electric power excitation. The sensing method is developed based on the shear strain gradient and the shear flexoelectric response of PVDF. A theoretical analysis is primarily presented for the design of the sensing structure. Then the structure of the PVDF sensing module is discussed and designed. The radius ratio of the sensing module is defined and then discussed according to the load, the strain gradient, the electrode area and the general electric charge output. The finite element method is used to analyze the mechanical properties of the designed PVDF sensing module. Then the theoretical sensitivity of the sensor is predicated as 0.9441 pC Nm-1. The experiment system setup is developed, and the sensing properties of the measurement mechanism are tested at frequencies of 0.5 Hz, 1 Hz, 1.5 Hz and 2 Hz using identical modules. The measurement range of the designed sensor is 0-1.68 Nm and the average sensitivity is measured as 0.8950 pC Nm-1. The experimental results agree well with the theoretically predicted results. These results prove that the torque sensing method based on un-polarized PVDF is suitable for measurement of dynamic torque loads with a flexoelectricity-based mechanism. When using this method, external electric power excitation of the sensing module is no longer required.

  1. Joint Dictionary Learning-Based Non-Negative Matrix Factorization for Voice Conversion to Improve Speech Intelligibility After Oral Surgery.

    Science.gov (United States)

    Fu, Szu-Wei; Li, Pei-Chun; Lai, Ying-Hui; Yang, Cheng-Chien; Hsieh, Li-Chun; Tsao, Yu

    2017-11-01

    Objective: This paper focuses on machine learning based voice conversion (VC) techniques for improving the speech intelligibility of surgical patients who have had parts of their articulators removed. Because of the removal of parts of the articulator, a patient's speech may be distorted and difficult to understand. To overcome this problem, VC methods can be applied to convert the distorted speech such that it is clear and more intelligible. To design an effective VC method, two key points must be considered: 1) the amount of training data may be limited (because speaking for a long time is usually difficult for postoperative patients); 2) rapid conversion is desirable (for better communication). Methods: We propose a novel joint dictionary learning based non-negative matrix factorization (JD-NMF) algorithm. Compared to conventional VC techniques, JD-NMF can perform VC efficiently and effectively with only a small amount of training data. Results: The experimental results demonstrate that the proposed JD-NMF method not only achieves notably higher short-time objective intelligibility (STOI) scores (a standardized objective intelligibility evaluation metric) than those obtained using the original unconverted speech but is also significantly more efficient and effective than a conventional exemplar-based NMF VC method. Conclusion: The proposed JD-NMF method may outperform the state-of-the-art exemplar-based NMF VC method in terms of STOI scores under the desired scenario. Significance: We confirmed the advantages of the proposed joint training criterion for the NMF-based VC. Moreover, we verified that the proposed JD-NMF can effectively improve the speech intelligibility scores of oral surgery patients. Objective: This paper focuses on machine learning based voice conversion (VC) techniques for improving the speech intelligibility of surgical patients who have had parts of their articulators removed. Because of the removal of parts of the articulator, a patient

  2. Direction of Serbian Trade: Gravity Model Based on Pool Data

    Directory of Open Access Journals (Sweden)

    Vladimir Ristanovic

    2017-05-01

    Full Text Available The objective of this paper is to evaluate the effects of bilateral trade between Serbia and EU countries in the period 2001-2015 on the basis of a gravity model. So far in research papers the gravity model has been used for the evaluation of effects of trade among different countries. The gravity model, which combines the cross-section data and the time-series data, has been estimated to the panel data. Estimated results based on a sample of 28 countries reveal that the economic size of foreign countries, the market size of trading partners (the number of inhabitants, and the geographical distance produce altogether huge effects on Serbia’s total trade and exports. Border and language factors have also been taken into account. The research leaves room for further scientific analyses and provides guidance for trade policy creators in analyses for directions of the Serbian trade. This research is based on complex econometric analyses and a recognised model, and shows that there is considerable room for the growth of bilateral trade between Serbia and EU.

  3. Analytical Devices Based on Direct Synthesis of DNA on Paper.

    Science.gov (United States)

    Glavan, Ana C; Niu, Jia; Chen, Zhen; Güder, Firat; Cheng, Chao-Min; Liu, David; Whitesides, George M

    2016-01-05

    This paper addresses a growing need in clinical diagnostics for parallel, multiplex analysis of biomarkers from small biological samples. It describes a new procedure for assembling arrays of ssDNA and proteins on paper. This method starts with the synthesis of DNA oligonucleotides covalently linked to paper and proceeds to assemble microzones of DNA-conjugated paper into arrays capable of simultaneously capturing DNA, DNA-conjugated protein antigens, and DNA-conjugated antibodies. The synthesis of ssDNA oligonucleotides on paper is convenient and effective with 32% of the oligonucleotides cleaved and eluted from the paper substrate being full-length by HPLC for a 32-mer. These ssDNA arrays can be used to detect fluorophore-linked DNA oligonucleotides in solution, and as the basis for DNA-directed assembly of arrays of DNA-conjugated capture antibodies on paper, detect protein antigens by sandwich ELISAs. Paper-anchored ssDNA arrays with different sequences can be used to assemble paper-based devices capable of detecting DNA and antibodies in the same device and enable simple microfluidic paper-based devices.

  4. Acceptability of an Embodied Conversational Agent-based Computer Application for Hispanic Women

    Science.gov (United States)

    Wells, Kristen J.; Vázquez-Otero, Coralia; Bredice, Marissa; Meade, Cathy D.; Chaet, Alexis; Rivera, Maria I.; Arroyo, Gloria; Proctor, Sara K.; Barnes, Laura E.

    2015-01-01

    There are few Spanish language interactive, technology-driven health education programs. Objectives of this feasibility study were to: 1) learn more about computer and technology usage among Hispanic women living in a rural community; and 2) evaluate acceptability of the concept of using an embodied conversational agent (ECA) computer application among this population. A survey about computer usage history and interest in computers was administered to a convenience sample of 26 women. A sample video prototype of a hospital discharge ECA was administered followed by questions to gauge opinion about the ECA. Data indicate women exhibited both a high level of computer experience and enthusiasm for the ECA. Feedback from community is essential to ensure equity in state of the art dissemination of health information. Hay algunos programas interactivos en español que usan la tecnología para educar sobre la salud. Los objetivos de este estudio fueron: 1) aprender más sobre el uso de computadoras y tecnología entre mujeres Hispanas que viven en comunidades rurales y 2) evaluar la aceptabilidad del concepto de usar un programa de computadora utilizando un agente de conversación encarnado (ECA) en esta población. Se administro una encuesta sobre el historial de uso y del interés de aprender sobre computadoras fue a 26 mujeres por muestreo de conveniencia. Un ejemplo del prototipo ECA en forma de video de un alta hospitalaria fue administrado y fue seguido por preguntas sobre la opinión que tenían del ECA. Los datos indican que las mujeres mostraron un alto nivel de experiencia con las computadoras y un alto nivel de entusiasmo sobre el ECA. La retroalimentación de la comunidad es esencial para asegurar equidad en la diseminación de información sobre la salud con tecnología de punta. PMID:26671558

  5. Usefulness of direct-conversion flat-panel detector system as a quality assurance tool for high-dose-rate 192Ir source.

    Science.gov (United States)

    Miyahara, Yoshinori; Kitagaki, Hajime; Nishimura, Tomonori; Itakura, Kanae; Takahashi, Shinobu; Yokokawa, Masaki; Uchida, Nobue; Inomata, Taisuke

    2015-01-08

    The routine quality assurance (QA) procedure for a high-dose-rate (HDR) 192Ir radioactive source is an important task to provide appropriate brachytherapy. Traditionally, it has been difficult to obtain good quality images using the 192Ir source due to irradiation from the high-energy gamma rays. However, a direct-conversion flat-panel detector (d-FPD) has made it possible to confirm the localization and configuration of the 192Ir source. The purpose of the present study was to evaluate positional and temporal accuracy of the 192Ir source using a d-FPD system, and the usefulness of d-FPD as a QA tool. As a weekly verification of source positional accuracy test, we obtained 192Ir core imaging by single-shot radiography for three different positions (1300/1400/1500 mm) of a check ruler. To acquire images for measurement of the 192Ir source movement distance with varying interval steps (2.5/5.0/10.0 mm) and temporal accuracy, we used the high-speed image acquisition technique and digital subtraction. For accuracy of the 192Ir source dwell time, sequential images were obtained using various dwell times ranging from 0.5 to 30.0 sec, and the acquired number of image frames was assessed. Analysis of the data was performed using the measurement analysis function of the d-FPD system. Although there were slight weekly variations in source positional accuracy, the measured positional errors were less than 1.0 mm. For source temporal accuracy, the temporal errors were less than 1.0%, and the correlation between acquired frames and programmed time showed excellent linearity (R2 = 1). All 192Ir core images were acquired clearly without image halation, and the data were obtained quantitatively. All data were successfully stored in the picture archiving and communication system (PACS) for time-series analysis. The d-FPD is considered useful as the QA tool for the 192Ir source.

  6. Strategic conversation

    Directory of Open Access Journals (Sweden)

    Nicholas Asher

    2013-08-01

    Full Text Available Models of conversation that rely on a strong notion of cooperation don’t apply to strategic conversation — that is, to conversation where the agents’ motives don’t align, such as courtroom cross examination and political debate. We provide a game-theoretic framework that provides an analysis of both cooperative and strategic conversation. Our analysis features a new notion of safety that applies to implicatures: an implicature is safe when it can be reliably treated as a matter of public record. We explore the safety of implicatures within cooperative and non cooperative settings. We then provide a symbolic model enabling us (i to prove a correspondence result between a characterisation of conversation in terms of an alignment of players’ preferences and one where Gricean principles of cooperative conversation like Sincerity hold, and (ii to show when an implicature is safe and when it is not. http://dx.doi.org/10.3765/sp.6.2 BibTeX info

  7. Neural Network Based Maximum Power Point Tracking Control with Quadratic Boost Converter for PMSG—Wind Energy Conversion System

    Directory of Open Access Journals (Sweden)

    Ramji Tiwari

    2018-02-01

    Full Text Available This paper proposes an artificial neural network (ANN based maximum power point tracking (MPPT control strategy for wind energy conversion system (WECS implemented with a DC/DC converter. The proposed topology utilizes a radial basis function network (RBFN based neural network control strategy to extract the maximum available power from the wind velocity. The results are compared with a classical Perturb and Observe (P&O method and Back propagation network (BPN method. In order to achieve a high voltage rating, the system is implemented with a quadratic boost converter and the performance of the converter is validated with a boost and single ended primary inductance converter (SEPIC. The performance of the MPPT technique along with a DC/DC converter is demonstrated using MATLAB/Simulink.

  8. DNA Methylation Analysis by Bisulfite Conversion Coupled to Double Multiplexed Amplicon-Based Next-Generation Sequencing (NGS).

    Science.gov (United States)

    Bashtrykov, Pavel; Jeltsch, Albert

    2018-01-01

    Methylation of cytosine bases in DNA is one of the main epigenetic signals regulating gene expression and chromatin structure. The distribution of DNA methylation in the genome has a cell-type-specific pattern and can be modulated by internal or external stimuli. One of the most powerful approaches to investigate DNA methylation patterns is bisulfite conversion of the DNA followed by DNA sequencing, which allows to determine methylation patterns at a single-cytosine resolution. Here, we present a protocol for bisulfite DNA methylation analysis of targeted genomic regions using amplicon-based next-generation sequencing (NGS) on an Illumina sequencing system. We use a PCR-free library generation approach and implement a nested strategy for double molecular barcoding of samples (combining indexing of adapters and in-line barcoding of individual amplicons) which allows highly multiplexed sequencing. Also, we discuss the main limitations of this technology in particular in relation to clonal DNA amplification and other PCR artifacts.

  9. Neural Network Compensation Control for Output Power Optimization of Wind Energy Conversion System Based on Data-Driven Control

    Directory of Open Access Journals (Sweden)

    T. Li

    2012-01-01

    Full Text Available Due to the uncertainty of wind and because wind energy conversion systems (WECSs have strong nonlinear characteristics, accurate model of the WECS is difficult to be built. To solve this problem, data-driven control technology is selected and data-driven controller for the WECS is designed based on the Markov model. The neural networks are designed to optimize the output of the system based on the data-driven control system model. In order to improve the efficiency of the neural network training, three different learning rules are compared. Analysis results and SCADA data of the wind farm are compared, and it is shown that the method effectively reduces fluctuations of the generator speed, the safety of the wind turbines can be enhanced, the accuracy of the WECS output is improved, and more wind energy is captured.

  10. Photoelectrochemical conversion of toluene to methylcyclohexane as an organic hydride by Cu 2ZnSnS 4-based photoelectrode assemblies

    KAUST Repository

    Wang, Peng

    2012-02-08

    Direct photoelectrochemical conversion of toluene (TL) to methylcyclohexane (MC) with water has been examined as an organic hydride conversion using light irradiation. The production of MC from TL was observed on Pt/CdS/Cu 2ZnSnS 4/Mo photoelectrodes with anion-type ionomer membrane assemblies. A cathodic photocurrent was observed below 0.7 V vs RHE (V RHE) in 0.1 M Na 2SO 4/NaOH (pH 9.5) aqueous solution, and an apparent photocurrent density of 0.5 mA cm -2 was obtained at 0 V RHE under the irradiation of a 300 W Xe lamp with a 420 nm cutoff filter. The yield of MC was measured by gas chromatography, and an 88% faradaic efficiency was estimated. This study suggests the possibility of direct energy conversion from solar energy to MC as an energy carrier of organic hydrides. © 2012 American Chemical Society.

  11. Selective Chemical Conversion of Sugars in Aqueous Solutions without Alkali to Lactic Acid Over a Zn-Sn-Beta Lewis Acid-Base Catalyst

    Science.gov (United States)

    Dong, Wenjie; Shen, Zheng; Peng, Boyu; Gu, Minyan; Zhou, Xuefei; Xiang, Bo; Zhang, Yalei

    2016-05-01

    Lactic acid is an important platform molecule in the synthesis of a wide range of chemicals. However, in aqueous solutions without alkali, its efficient preparation via the direct catalysis of sugars is hindered by a side dehydration reaction to 5-hydroxymethylfurfural due to Brønsted acid, which originates from organic acids. Herein, we report that a previously unappreciated combination of common two metal mixed catalyst (Zn-Sn-Beta) prepared via solid-state ion exchange synergistically promoted this reaction. In water without a base, a conversion exceeding 99% for sucrose with a lactic acid yield of 54% was achieved within 2 hours at 190 °C under ambient air pressure. Studies of the acid and base properties of the Zn-Sn-Beta zeolite suggest that the introduction of Zn into the Sn-Beta zeolite sequentially enhanced both the Lewis acid and base sites, and the base sites inhibited a series of side reactions related to fructose dehydration to 5-hydroxymethylfurfural and its subsequent decomposition.

  12. A novel DNA restriction technology based on laser pulse energy conversion on sequence-specific bound metal nanoparticles

    Science.gov (United States)

    Csaki, Andrea; Maubach, Gunter; Garwe, Frank; Steinbrueck, Andrea; Koenig, Karsten; Fritzsche, Wolfgang

    2005-03-01

    DNA restriction is a basic method in today"s molecular biology. Besides application for DNA manipulation, this method is used in DNA analytics for 'restriction analysis'. Thereby DNA is digested by sequence specific restriction enzymes, and the length distribution of the resulting fragments is detected by gel electrophoresis. Differences in the sequence lead to different restriction patterns. A disadvantage of this standard method is the limitation to a small set of fixed sequences, so that the assay can not be adapted to any sequence of interest (e.g. SNP). We designed a scheme for DNA restriction in order to provide access to any desired sequence, based on laser light conversion on sequence-specific positioned metal nanoparticles. Especially gold nanoparticles are known for their interesting optical properties caused by plasmon resonance. The resulting absorption can be used to convert laser light pulses into heat, resulting in nanoparticle destruction. We work on the combination of this principle with DNA-modification of nanoparticles and the sequence-specific binding (hybridization) of these DNA-nanoparticle complexes along DNA molecules. Different mechanisms of light-conversion were studied, and the destructive effect of laser light on the nanoparticles and DNA is demonstrated.

  13. Solution-Processed Organic Solar Cells with Power Conversion Efficiencies of 2.5% using Benzothiadiazole/Imide-Based Acceptors

    KAUST Repository

    Bloking, Jason T.

    2011-12-27

    A new series of electron-deficient molecules based on a central benzothiadiazole moiety flanked with vinylimides has been synthesized via Heck chemistry and used in solution-processed organic photovoltaics (OPV). Two new compounds, 4,7-bis(4-(N-hexyl-phthalimide)vinyl)benzo[c]1,2,5-thiadiazole (PI-BT) and 4,7-bis(4-(N-hexyl-naphthalimide)vinyl)benzo[c]1,2,5-thiadiazole (NI-BT), show significantly different behaviors in bulk heterojunction (BHJ) solar cells using poly(3-hexylthiophene) (P3HT) as the electron donor. Two-dimensional grazing incidence X-ray scattering (2D GIXS) experiments demonstrate that PI-BT shows significant crystallization in spin-coated thin films, whereas NI-BT does not. Density functional theory (DFT) calculations predict that while PI-BT maintains a planar structure in the ground state, steric interactions cause a twist in the NI-BT molecule, likely preventing significant crystallization. In BHJ solar cells with P3HT as donor, PI-BT devices achieved a large open-circuit voltage of 0.96 V and a maximum device power-conversion efficiency of 2.54%, whereas NI-BT containing devices only achieved 0.1% power-conversion efficiency. © 2011 American Chemical Society.

  14. Novel Integration of Perovskite Solar Cell and Supercapacitor Based on Carbon Electrode for Hybridizing Energy Conversion and Storage.

    Science.gov (United States)

    Liu, Zhiyong; Zhong, Yan; Sun, Bo; Liu, Xingyue; Han, Jinghui; Shi, Tielin; Tang, Zirong; Liao, Guanglan

    2017-07-12

    Power packs integrating both photovoltaic parts and energy storage parts have gained great scientific and technological attention due to the increasing demand for green energy and the tendency for miniaturization and multifunctionalization in electronics industry. In this study, we demonstrate novel integration of perovskite solar cell and solid-state supercapacitor for power packs. The perovskite solar cell is integrated with the supercapacitor based on common carbon electrodes to hybridize photoelectric conversion and energy storage. The power pack achieves a voltage of 0.84 V when the supercapacitor is charged by the perovskite solar cell under the AM 1.5G white light illumination with a 0.071 cm 2 active area, reaching an energy storage proportion of 76% and an overall conversion efficiency of 5.26%. When the supercapacitor is precharged at 1.0 V, an instant overall output efficiency of 22.9% can be achieved if the perovskite solar cell and supercapacitor are connected in series, exhibiting great potential in the applications of solar energy storage and flexible electronics such as portable and wearable devices.

  15. Demonstration of polarization sensitivity of emulsion-based pair conversion telescope for cosmic gamma-ray polarimetry

    Energy Technology Data Exchange (ETDEWEB)

    Ozaki, Keita, E-mail: ozaki@radix.h.kobe-u.ac.jp [Kobe University, 3-11, Tsurukabuto, Nada-ku, Kobe 657-8501 (Japan); Takahashi, Satoru, E-mail: satoru@radix.h.kobe-u.ac.jp [Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan); Aoki, Shigeki; Kamada, Keiki; Kaneyama, Taichi; Nakagawa, Ryo; Rokujo, Hiroki [Kobe University, 3-11, Tsurukabuto, Nada-ku, Kobe 657-8501 (Japan)

    2016-10-11

    Linear polarization of high-energy gamma-rays (10MeV–100 GeV) can be detected by measuring the azimuthal angle of electron–positron pairs and observing the modulation of the azimuthal distribution. To demonstrate the gamma-ray polarization sensitivity of emulsion, we conducted a test using a polarized gamma-ray beam (0.8–2.4 GeV) at SPring-8/LEPS. Emulsion tracks were reconstructed using scanning data, and gamma-ray events were selected automatically. Using an optical microscope, out of the 2381 gamma-ray conversions that were observed, 1372 remained after event selection, on the azimuthal angle distribution of which we measured the modulation. From the distribution of the azimuthal angles of the selected events, a modulation factor of 0.21+0.11−0.09 was measured, from which the detection of a non-zero modulation was established with a significance of 3.06σ. This attractive polarimeter will be applied to the GRAINE project, a balloon-borne experiment that observes 10–100 GeV cosmic gamma-rays with an emulsion-based pair conversion telescope.

  16. Measurement of the isolated direct photon cross section with conversions in $p \\bar{p}$ collisions at $\\sqrt{s}$ = 1.8-TeV

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Carter Randolph [Harvard U.

    2002-05-01

    We present a measurement of the isolated direct photon cross section in pp¹ collisions at p s = 1:8 TeV using data collected between 1994 and 1995 by the Collider Detector at Fermilab (CDF). The measurement is based on events where the photon converts into an electron-positron pair in the material of the inner detector, resulting in a two track event signature. To remove ¼ 0 ! °° and ´ ! °° events from the data we have developed a novel background subtraction technique based in electron E/p. We ¯nd that the shape of the cross section as a function of photon pT is poorly described by next-to-leading-order QCD predictions, but agrees well with previous CDF measurements. This is strong evidence that improvements in the calculation are needed to explain the data.

  17. Energy Conversion in Protocells with Natural Nanoconductors

    Directory of Open Access Journals (Sweden)

    Jian Xu

    2012-01-01

    Full Text Available While much nanotechnology leverages solid-state devices, here we present the analysis of designs for hybrid organic-inorganic biomimetic devices, “protocells,” based on assemblies of natural ion channels and ion pumps, “nanoconductors,” incorporated into synthetic supported lipid bilayer membranes. These protocells mimic the energy conversion scheme of natural cells and are able to directly output electricity. The electrogenic mechanisms have been analyzed and designs were optimized using numerical models. The parameters that affect the energy conversion are quantified, and limits for device performance have been found using numerical optimization. The electrogenic performance is compared to conventional and emerging technologies and plotted on Ragone charts to allow direct comparisons. The protocell technologies summarized here may be of use for energy conversion where large-scale ion concentration gradients are available (such as the intersection of fresh and salt water sources or small-scale devices where low power density would be acceptable.

  18. 640 Gbit/s return-to-zero to non-return-to-zero format conversion based on optical linear spectral phase filtering

    DEFF Research Database (Denmark)

    Maram, Reza; Kong, Deming; Galili, Michael

    2016-01-01

    We propose a novel approach for all-optical return-to-zero (RZ) to non-return-to-zero (NRZ) telecommunication data format conversion based on linear spectral phase manipulation of an RZ data signal. The operation principle is numerically analyzed and experimentally validated through successful...... format conversion of a 640 Gbit/s coherent RZ signal into the equivalent NRZ time-domain data using a simple phase filter implemented by a commercial optical waveshaper. (C) 2015 Optical Society of America...

  19. Conversation Thread Extraction and Topic Detection in Text-Based Chat

    National Research Council Canada - National Science Library

    Adams, Paige H

    2008-01-01

    Text-based chat systems are widely used within the Department of Defense, but the standard systems available do not provide robust capabilities for search, information retrieval, or information assurance...

  20. Direct Problem-Based Learning (DPBL): A Framework for Integrating Direct Instruction and Problem-Based Learning Approach

    Science.gov (United States)

    Winarno, Sri; Muthu, Kalaiarasi Sonai; Ling, Lew Sook

    2018-01-01

    Direct instruction approach has been widely used in higher education. Many studies revealed that direct instruction improved students' knowledge. The characteristics of direct instruction include the subject delivered through face-to-face interaction with the lecturers and materials that sequenced deliberately and taught explicitly. However,…

  1. Solar energy conversion systems

    CERN Document Server

    Brownson, Jeffrey R S

    2013-01-01

    Solar energy conversion requires a different mind-set from traditional energy engineering in order to assess distribution, scales of use, systems design, predictive economic models for fluctuating solar resources, and planning to address transient cycles and social adoption. Solar Energy Conversion Systems examines solar energy conversion as an integrative design process, applying systems thinking methods to a solid knowledge base for creators of solar energy systems. This approach permits different levels of access for the emerging broad audience of scientists, engineers, architects, planners

  2. Proton conducting polymeric materials for hydrogen based electrochemical energy conversion technologies

    DEFF Research Database (Denmark)

    Aili, David

    impurity tolerance of the catalysts, especially for the fuel cell anode. From a system engineering point of view it also allows for simplified cooling and water management and better possibilities for heat recovery. Furthermore, a higher operating temperature is strongly beneficial when the cell...... of crystallinity than Nafion®. The melting point of the large crystalline regions is also considerably higher than that of Nafion®, which allows for better mechanical characteristics at elevated operating temperatures. The low equivalent weight of Aquivion™ also resulted in high phosphoric acid uptake, which...... these conditions, the average cell voltage decay rate of the MEA based on the non-cured reference membrane (308 μV h-1) was more than 700% higher compared with that of the MEA based on the cured PBI membrane. The results confirmed that the long term durability of phosphoric acid doped PBI based high temperature...

  3. Doubling-resolution analog-to-digital conversion based on PIC18F45K80

    Directory of Open Access Journals (Sweden)

    Yueyang Yuan

    2014-08-01

    Full Text Available Aiming at the analog signal being converted into the digital with a higher precision, a method to improve the analog-to-digital converter (ADC resolution is proposed and described. Based on the microcomputer PIC18F45K80 in which the internal ADC modules are embedded, a circuit is designed for doubling the resolution of ADC. According to the circuit diagram, the mathematical formula for calculating this resolution is derived. The corresponding software and print circuit board assembly is also prepared. With the experiment, a 13 bit ADC is achieved based on the 12 bit ADC module predesigned in the PIC18F45K80.

  4. Direction of arrival estimation based on information geometry

    NARCIS (Netherlands)

    Coutiño Minguez, M.A.; Pribic, R; Leus, G.J.T.; Dong, Min; Zheng, Thomas Fang

    2016-01-01

    In this paper, a new direction of arrival (DOA) estimation approach is devised using concepts from information geometry (IG). The proposed method uses geodesic distances in the statistical manifold of probability distributions parametrized by their covariance matrix to estimate the direction of

  5. Design of the steam generator in an energy conversion system based on the aluminum combustion with water

    International Nuclear Information System (INIS)

    Mercati, Stefano; Milani, Massimo; Montorsi, Luca; Paltrinieri, Fabrizio

    2012-01-01

    Highlights: ► Development of a numerical approach for the analysis of a co-generation system based on the aluminum water reaction. ► Construction of system operating maps for estimating the system behavior. ► Comparison of two different designs of the steam generator for the system. ► Definition of the operating range where each configuration provides the best performance. -- Abstract: The paper shows the preliminary design of the superheated steam generator to be used in a novel hydrogen production and energy conversion system based on the combustion of aluminum particles with water. The system is aimed at producing hydrogen and pressurized superheated steam, using the heat released by the Al–H 2 O reaction. The interest on this type of technology arises because of the possibility of obtaining hydrogen with very low pollutant and greenhouse gas emissions, compared to the traditional hydrogen production systems, such as the steam reforming from methane. The analysis of the combustion chamber and the heat recovery system is carried out by means of a lumped and distributed parameter numerical approach. The multi phase and gas mixture theoretical principles are used both to characterize the mass flow rate and the heat release in the combustion chamber and within the heat exchangers in order to relate the steam generator performance to the system operating parameters. Finally, the influence of the steam generator performance on the whole energy conversion system behavior is addressed, with particular care to the evaluation of the total power and efficiency variation with the combustion parameters.

  6. Continuous weighing of conveyor-transported materials based on gamma radiation conversion to electric current

    International Nuclear Information System (INIS)

    The principle is described of the continuous weighing of conveyer-transported materials applied in the food industry. The weighing technique is based on the measurement of the absorption of gamma radiation emitted by a source located behind the material to be scaled. (Z.M.)

  7. Space-Based Solar Power Conversion and Delivery Systems Study. Volume 3: Microwave Power Transmission Studies

    Science.gov (United States)

    1977-01-01

    The Microwave Fower Beam Ionosphere effects and critical interfaces between th Microwave Power Transmission System (MPTS) and the Satellite were studied as part of the NASA/MSFC continuing research on the feasibility of power transmission from geosynchronous orbit. Theoretical predications of ionospheric modifications produced by the direct interaction of the MPTS on the earth's upper atmosphere are used to determine their impact on the performance of the Microwave Power Beam and Pilot Beam System as well as on other RF systems effected by the ionosphere. A technology program to quantitatively define these interactions is developed. Critical interface areas between the MPTS and the satellite which could have a major impact on cost and performance of the power system are idenfified and analyzed. The areas selected include: use of either a 20 kV versus 40 kV Amplitron, thermal blockage effects of Amplitron heat radiation by the satellite structure, effect of dielectric carry-through structure on power beam, and effect of material sublimation on performance of the Amplitron in Geosynchronous Orbit.

  8. An Innovative Control Strategy to Improve the Fault Ride-Through Capability of DFIGs Based on Wind Energy Conversion Systems

    Directory of Open Access Journals (Sweden)

    Vandai Le

    2016-01-01

    Full Text Available An innovative control strategy is proposed for enhancing the low voltage ride-through (LVRT capability of a doubly fed induction generator based on wind energy conversion systems (DFIG-WECS. Within the proposed control method, the current control loops of the rotor side converter (RSC are developed based on passivity theory. The control scheme for the grid side converter (GSC is designed based on a two-term approach to keep the DC-link voltage close to a given value. The first term based on the maximal voltage of GSC is introduced in the GSC control loops as a reference reactive current. The second one reflecting the instantaneous unbalanced power flow between the RSC and GSC is also introduced in the GSC control loops as a disturbance considering the instantaneous power of the grid filter to compensate the instantaneous rotor power. The effectiveness of the proposed control strategy is verified via time domain simulation of a 2.0 MW-575 V DFIG-WECS using PSCAD/EMTP. Simulation results show that the control of the DFIG with the proposed approach can improve the LVRT capability better than with the conventional one.

  9. Efficacy of melody-based aphasia therapy may strongly depend on rhythm and conversational speech formulas

    OpenAIRE

    Benjamin Stahl

    2014-01-01

    Left-hemisphere stroke patients suffering from language and speech disorders are often able to sing entire pieces of text fluently. This finding has inspired a number of melody-based rehabilitation programs – most notable among them a treatment known as Melodic Intonation Therapy – as well as two fundamental research questions. When the experimental design focuses on one point in time (cross section), one may determine whether or not singing has an immediate effect on syllable production in p...

  10. Parallel octree-based hexahedral mesh generation for eulerian to lagrangian conversion.

    Energy Technology Data Exchange (ETDEWEB)

    Staten, Matthew L.; Owen, Steven James

    2010-09-01

    Computational simulation must often be performed on domains where materials are represented as scalar quantities or volume fractions at cell centers of an octree-based grid. Common examples include bio-medical, geotechnical or shock physics calculations where interface boundaries are represented only as discrete statistical approximations. In this work, we introduce new methods for generating Lagrangian computational meshes from Eulerian-based data. We focus specifically on shock physics problems that are relevant to ASC codes such as CTH and Alegra. New procedures for generating all-hexahedral finite element meshes from volume fraction data are introduced. A new primal-contouring approach is introduced for defining a geometric domain. New methods for refinement, node smoothing, resolving non-manifold conditions and defining geometry are also introduced as well as an extension of the algorithm to handle tetrahedral meshes. We also describe new scalable MPI-based implementations of these procedures. We describe a new software module, Sculptor, which has been developed for use as an embedded component of CTH. We also describe its interface and its use within the mesh generation code, CUBIT. Several examples are shown to illustrate the capabilities of Sculptor.

  11. Development and modelisation of a hydro-power conversion system based on vortex induced vibration

    Science.gov (United States)

    Lefebure, David; Dellinger, Nicolas; François, Pierre; Mosé, Robert

    2016-11-01

    The Vortex Induced Vibration (VIV) phenomenon leads to mechanical issues concerning bluff bodies immerged in fluid flows and have therefore been studied by numerous authors. Moreover, an increasing demand for energy implies the development of alternative, complementary and renewable energy solutions. The main idea of EauVIV project consists in the use of VIV rather than its deletion. When rounded objects are immerged in a fluid flow, vortices are formed and shed on their downstream side, creating a pressure imbalance resulting in an oscillatory lift. A convertor modulus consists of an elastically mounted, rigid cylinder on end-springs, undergoing flow- induced motion when exposed to transverse fluid-flow. These vortices induce cyclic lift forces in opposite directions on the circular bar and cause the cylinder to vibrate up and down. An experimental prototype was developed and tested in a free-surface water channel and is already able to recover energy from free-stream velocity between 0.5 and 1 m.s -1. However, the large number of parameters (stiffness, damping coefficient, velocity of fluid flow, etc.) associated with its performances requires optimization and we choose to develop a complete tridimensionnal numerical model solution. A 3D numerical model has been developed in order to represent the real system behavior and improve it through, for example, the addition of parallel cylinders. The numerical model build up was carried out in three phases. The first phase consists in establishing a 2D model to choose the turbulence model and quantify the dependence of the oscillations amplitudes on the mesh size. The second corresponds to a 3D simulation with cylinder at rest in first time and with vertical oscillation in a second time. The third and final phase consists in a comparison between the experimental system dynamic behavior and its numerical model.

  12. An assay for secologanin in plant tissues based on enzymatic conversion into strictosidine

    DEFF Research Database (Denmark)

    Hallard, Didier; van der Heijden, Robert; Contin, Adriana

    1998-01-01

    The secoiridoid glucoside secologanin is the terpenoid building block in the biosynthesis of terpenoid indole alkaloids. A method for its determination in plant tissues and cell suspension cultures has been developed. This assay is based on the condensation of secologanin with tryptamine, yielding...... of STR for secologanin, in combination with a sensitive and selective HPLC system, allows a simple extraction of secologanin from plant tissue. The detection limit of this methos is 15 ng secologanin. Using this assay, secologanin contents were determined in tissues of various plant species; Lonicera...

  13. Improved Control Strategy for DFIG-based Wind Energy Conversion System during Grid Voltage Disturbances

    DEFF Research Database (Denmark)

    Zhu, Rongwu

    of stator flux performances and its effects on the DFIG, the improved FOVC and high stability vector-based DPC control are proposed, respectively, to fast decay the transient flux and to improve dynamic responses. By using Bode diagram and root locus, the improved FOVC strategy is designed to fast decay...... and rotor current. The degraded performances of the DFIG may reduce the life time of the drive train, affect the system stability, and even destroy the power converters. To improve the system performance, stability and reliability, it must improve the control strategy for the DFIG experiencing non...... flux is affected by the control strategy of the rotor current and stator time constant. The stator transient flux is harmful to the DFIG, because it may cause oscillations of the electromagnetic torque, stator or rotor current, DC-link voltage, and stator active and reactive power. On the basis...

  14. Availability and conversion to energy potentials of wood-based industry residues in Cameroon

    International Nuclear Information System (INIS)

    Simo, A.; Siyam Siew, S.

    2000-01-01

    The importance of biomass as the most accessible primary energy source in Cameroon is presented. The valorization of wood wastes and residues is seen as a way of implementing the sustainable use of biomass resources. A recent survey of wood-based industries in Cameroon reveals that large volumes of industrial wood residues are generated in the rain forest areas and are inefficiently used. Important quantities are lost in the form of burning in the four main forestry provinces, while other parts of the country suffer from fuelwood shortage. With the exception of the plywood factories, the wood industry is essentially dependent on commercial energy. An analysis made to show the economic and environmental benefits of converting wood residues to energy for industrial and domestic use is presented. (author)

  15. Coordinated Control Strategies for a Permanent Magnet Synchronous Generator Based Wind Energy Conversion System

    Directory of Open Access Journals (Sweden)

    Ramji Tiwari

    2017-09-01

    Full Text Available In this paper, a novel co-ordinated hybrid maximum power point tracking (MPPT-pitch angle based on a radial basis function network (RBFN is proposed for a variable speed variable pitch wind turbine. The proposed controller is used to maximise output power when the wind speed is low and optimise the power when the wind speed is high. The proposed controller provides robustness to the nonlinear characteristic of wind speed. It uses wind speed, generator speed, and generator power as input variables and utilises the duty cycle and the reference pitch angle as the output control variables. The duty cycle is used to control the converter so as to maximise the power output and the reference pitch angle is used to control the generator speed in order to control the generator output power in the above rated wind speed region. The effectiveness of the proposed controller was verified using MATLAB/Simulink software.

  16. An assay for secologanin in plant tissues based on enzymatic conversion into strictosidine

    DEFF Research Database (Denmark)

    Hallard, Didier; van der Heijden, Robert; Contin, Adriana

    1998-01-01

    strictosidine, a reaction catalysed by the enzyme strictosidine synthase (STR; E.C. 4.3.3.2). Subsequently, the formation of strictosidine is quantified by HPLC. STR was isolated from transgenic Nicotiana tabacum cells expressing a cDNA-derived gene coding for STR from Catharanthus roseus. The high specificity......The secoiridoid glucoside secologanin is the terpenoid building block in the biosynthesis of terpenoid indole alkaloids. A method for its determination in plant tissues and cell suspension cultures has been developed. This assay is based on the condensation of secologanin with tryptamine, yielding...... of STR for secologanin, in combination with a sensitive and selective HPLC system, allows a simple extraction of secologanin from plant tissue. The detection limit of this methos is 15 ng secologanin. Using this assay, secologanin contents were determined in tissues of various plant species; Lonicera...

  17. Sistem Scoring Conversion TOEFL Paper Based Test (PBT Politeknik Negeri Cilacap Menggunakan Metode User Centered Design

    Directory of Open Access Journals (Sweden)

    Cahya Vikasari

    2017-06-01

    Full Text Available Sistem komputer interaktif untuk dipakai oleh useruntuk mendukung pekerjannya. User merupakan object yang penting didalam pengembangan dan pembangun sistem. User adalah personal-personal yang terlibat langsung dalam pemakaian aplikasi. Konsep dari UCD adalah user sebagai pusat dari proses pengembangan sistem, dan tujuan/sifat-sifat, konteks dan lingkungan sistem semua didasarkan dari pengalaman pengguna Pembangunan sistem skoring test TOEFL paper based test (PBT di UPT bahasa politeknik negeri cilacapmenggunakan metode UCD. Dengan menggunakan metode UCD sistem dapat   mempermudah dan mempercepat pendaftaran oleh calon pendaftar dengan tampilan antarmuka yang user friendly , mempermudah proses pengelolaan data dan rekap data pendaftar, mempermudah pengkonversian skor TOEFL yang dilakukan secara otomatis, serta  meminimalisir terjadinya kesalahan, duplikasi data dan duplikasi kegiatan.

  18. Conversion of Component-Based Point Definition to VSP Model and Higher Order Meshing

    Science.gov (United States)

    Ordaz, Irian

    2011-01-01

    Vehicle Sketch Pad (VSP) has become a powerful conceptual and parametric geometry tool with numerous export capabilities for third-party analysis codes as well as robust surface meshing capabilities for computational fluid dynamics (CFD) analysis. However, a capability gap currently exists for reconstructing a fully parametric VSP model of a geometry generated by third-party software. A computer code called GEO2VSP has been developed to close this gap and to allow the integration of VSP into a closed-loop geometry design process with other third-party design tools. Furthermore, the automated CFD surface meshing capability of VSP are demonstrated for component-based point definition geometries in a conceptual analysis and design framework.

  19. Photonic generation of FCC-compliant UWB pulses based on modified Gaussian quadruplet and incoherent wavelength-to-time conversion

    Science.gov (United States)

    Mu, Hongqian; Wang, Muguang; Tang, Yu; Zhang, Jing; Jian, Shuisheng

    2018-03-01

    A novel scheme for the generation of FCC-compliant UWB pulse is proposed based on modified Gaussian quadruplet and incoherent wavelength-to-time conversion. The modified Gaussian quadruplet is synthesized based on linear sum of a broad Gaussian pulse and two narrow Gaussian pulses with the same pulse-width and amplitude peak. Within specific parameter range, FCC-compliant UWB with spectral power efficiency of higher than 39.9% can be achieved. In order to realize the designed waveform, a UWB generator based on spectral shaping and incoherent wavelength-to-time mapping is proposed. The spectral shaper is composed of a Gaussian filter and a programmable filter. Single-mode fiber functions as both dispersion device and transmission medium. Balanced photodetection is employed to combine linearly the broad Gaussian pulse and two narrow Gaussian pulses, and at same time to suppress pulse pedestals that result in low-frequency components. The proposed UWB generator can be reconfigured for UWB doublet by operating the programmable filter as a single-band Gaussian filter. The feasibility of proposed UWB generator is demonstrated experimentally. Measured UWB pulses match well with simulation results. FCC-compliant quadruplet with 10-dB bandwidth of 6.88-GHz, fractional bandwidth of 106.8% and power efficiency of 51% is achieved.

  20. Simulation-Based Communication Skills Training for Experienced Clinicians to Improve Family Conversations About Organ and Tissue Donation.

    Science.gov (United States)

    Potter, Julie Elizabeth; Gatward, Jonathan J; Kelly, Michelle A; McKay, Leigh; McCann, Ellie; Elliott, Rosalind M; Perry, Lin

    2017-12-01

    The approach, communication skills, and confidence of clinicians responsible for raising deceased organ donation may influence families' donation decisions. The aim of this study was to increase the preparedness and confidence of intensive care clinicians allocated to work in a "designated requester" role. We conducted a posttest evaluation of an innovative simulation-based training program. Simulation-based training enabled clinicians to rehearse the "balanced approach" to family donation conversations (FDCs) in the designated requester role. Professional actors played family members in simulated clinical settings using authentic scenarios, with video-assisted reflective debriefing. Participants completed an evaluation after the workshop. Simple descriptive statistical analysis and content analysis were performed. Between January 2013 and July 2015, 25 workshops were undertaken with 86 participants; 82 (95.3%) returned evaluations. Respondents were registered practicing clinicians; over half (44/82; 53.7%) were intensivists. Most attended a single workshop. Evaluations were overwhelmingly positive with the majority rating workshops as outstanding (64/80; 80%). Scenario fidelity, competence of the actors, opportunity to practice and receive feedback on performance, and feedback from actors, both in and out of character, were particularly valued. Most (76/78; 97.4%) reported feeling more confident about their designated requester role. Simulation-based communication training for the designated requester role in FDCs increased the knowledge and confidence of clinicians to raise the topic of donation.

  1. SNP discovery in nonmodel organisms: strand bias and base-substitution errors reduce conversion rates.

    Science.gov (United States)

    Gonçalves da Silva, Anders; Barendse, William; Kijas, James W; Barris, Wes C; McWilliam, Sean; Bunch, Rowan J; McCullough, Russell; Harrison, Blair; Hoelzel, A Rus; England, Phillip R

    2015-07-01

    Single nucleotide polymorphisms (SNPs) have become the marker of choice for genetic studies in organisms of conservation, commercial or biological interest. Most SNP discovery projects in nonmodel organisms apply a strategy for identifying putative SNPs based on filtering rules that account for random sequencing errors. Here, we analyse data used to develop 4723 novel SNPs for the commercially important deep-sea fish, orange roughy (Hoplostethus atlanticus), to assess the impact of not accounting for systematic sequencing errors when filtering identified polymorphisms when discovering SNPs. We used SAMtools to identify polymorphisms in a velvet assembly of genomic DNA sequence data from seven individuals. The resulting set of polymorphisms were filtered to minimize 'bycatch'-polymorphisms caused by sequencing or assembly error. An Illumina Infinium SNP chip was used to genotype a final set of 7714 polymorphisms across 1734 individuals. Five predictors were examined for their effect on the probability of obtaining an assayable SNP: depth of coverage, number of reads that support a variant, polymorphism type (e.g. A/C), strand-bias and Illumina SNP probe design score. Our results indicate that filtering out systematic sequencing errors could substantially improve the efficiency of SNP discovery. We show that BLASTX can be used as an efficient tool to identify single-copy genomic regions in the absence of a reference genome. The results have implications for research aiming to identify assayable SNPs and build SNP genotyping assays for nonmodel organisms. © 2014 John Wiley & Sons Ltd.

  2. Randomized Trial of a Family-based, Automated, Conversational Obesity Treatment Program for Underserved Populations

    Science.gov (United States)

    Wright, J. A.; Phillips, B.D.; Watson, B.L.; Newby, P.K.; Norman, G. J.; Adams, W.G.

    2013-01-01

    Objective To evaluate the acceptability and feasibility of a scalable obesity treatment program integrated with pediatric primary care and delivered using interactive voice technology (IVR) to families from underserved populations. Design and Methods Fifty parent-child dyads (child 9–12 yrs, BMI >95th percentile) were recruited from a pediatric primary care clinic and randomized to either an IVR or a wait-list control (WLC) group. The majority were lower-income, African-American (72%) families. Dyads received IVR calls for 12 weeks. Call content was informed by two evidenced-based interventions. Anthropometric and behavioral variables were assessed at baseline and 3 mo follow-up. Results Forty-three dyads completed the study. IVR parents ate 1 cup more fruit than WLC (p 75% agreed that the calls were useful, made for people like them, credible, and helped them eat healthy foods. Conclusion An obesity treatment program delivered via IVR may be an acceptable and feasible resource for families from underserved populations. PMID:23512915

  3. Design for Motor Controller in Hybrid Electric Vehicle Based on Vector Frequency Conversion Technology

    Directory of Open Access Journals (Sweden)

    Jing Lian

    2010-01-01

    Full Text Available Motor and its control technology are one of the main components of Hybrid Electric Vehicle (HEV. To meet HEV's fast torque response, vector control algorithm based on rotor flux-oriented and simulation model is concerned and modular designs for controller's hardware and software are presented in the paper in order to build a platform to achieve the vector control of asynchronous induction motor. Analyze the controller's electromagnetic compatibility, introduce the corresponding antijamming measures to assure the normal operation of the electromagnetic sensitive devices such as CAN bus; experiment proves that the measure is practical and feasible. On the basis of the control logic correct, such as improving CAN bus communication reliability, assuring power-on sequence and fault treatment, carry on the motor bench experiment, test its static properties, and adjust the controller parameters. The experimental results show that the designed driving system has the performance of low speed and high torque, a wide range of variable speed and high comprehensive efficiency.

  4. Base-Free, One-Pot Chemocatalytic Conversion of Glycerol to Methyl Lactate using Supported Gold Catalysts

    NARCIS (Netherlands)

    Pazhavelikkakath Purushothaman, Rajeesh Kumar; van Haveren, Jacco; Melian Cabrera, Ignacio; van Eck, Ernst R.H.; Heeres, Hero J.

    We report an efficient one-pot conversion of glycerol (GLY) to methyl lactate (MLACT) in methanol in good yields (73% at 95% GLY conversion) by using Au nanoparticles on commercially available ultra-stable zeolite-Y (USY) as the catalyst (160 degrees C, air, 47bar pressure, 0.25M GLY, GLY-to-Au mol

  5. Base-Free, One-Pot Chemocatalytic Conversion of Glycerol to Methyl Lactate using Supported Gold Catalysts

    NARCIS (Netherlands)

    Purushothaman, R.K.P.; Haveren, van J.; Melian-Cabrera, I.; Eck, van E.R.H.; Heeres, H.J.

    2014-01-01

    We report an efficient one-pot conversion of glycerol (GLY) to methyl lactate (MLACT) in methanol in good yields (73% at 95% GLY conversion) by using Au nanoparticles on commercially available ultra-stable zeolite-Y (USY) as the catalyst (160 degrees C, air, 47bar pressure, 0.25M GLY, GLY-to-Au mol

  6. Conversational Competence in Academic Settings

    Science.gov (United States)

    Bowman, Richard F.

    2014-01-01

    Conversational competence is a process, not a state. Ithaca does not exist, only the voyage to Ithaca. Vibrant campuses are a series of productive conversations. At its core, communicative competence in academic settings mirrors a collective search for meaning regarding the purpose and direction of a campus community. Communicative competence…

  7. Decision - making of Direct Customers Based on Available Transfer Capability

    Science.gov (United States)

    Quan, Tang; Zhaohang, Lin; Huaqiang, Li

    2017-05-01

    Large customer direct-power-purchasing is a hot spot in the electricity market reform. In this paper, the author established an Available Transfer Capability (ATC) model which takes uncertain factors into account, applied the model into large customer direct-power-purchasing transactions and improved the reliability of power supply during direct-power-purchasing by introducing insurance theory. The author also considered the customers loss suffered from power interruption when building ATC model, established large customer decision model, took purchasing quantity of power from different power plants and reserved capacity insurance as variables, targeted minimum power interruption loss as optimization goal and best solution by means of particle swarm algorithm to produce optimal power purchasing decision of large consumers. Simulation was made through IEEE57 system finally and proved that such method is effective.

  8. Toxicogenomics-based identification of mechanisms for direct immunotoxicity.

    Science.gov (United States)

    Shao, Jia; Katika, Madhumohan R; Schmeits, Peter C J; Hendriksen, Peter J M; van Loveren, Henk; Peijnenburg, Ad A C M; Volger, Oscar L

    2013-10-01

    Compounds with direct immunotoxic properties, including metals, mycotoxins, agricultural pesticides, and industrial chemicals, form potential human health risks due to exposure through food, drinking water, and the environment. Insights into the mechanisms of action are currently lacking for the majority of these direct immunotoxicants. Therefore, the present work aimed to gain insights into the molecular mechanisms underlying direct immunotoxicity. To this end, we assessed in vitro the effects of 31 test compounds on the transcriptome of the human Jurkat T-cell line. These compounds included direct immunotoxicants, immunosuppressive drugs with different mode of actions, and nonimmunotoxic control chemicals. Pathway analysis of the microarray data allowed us to identify canonical pathways and Gene Ontology processes that were transcriptionally regulated in common by immunotoxicants (1) with structural similarities, such as tributyltin chloride and tributyltin oxide that activated the retinoic acid/X receptor signaling pathway and (2) without structural similarities, such as As2O3, dibutyltin chloride, diazinon, MeHg, ochratoxin A (OTA), S9-treated OTA, S9-treated cyclophosphamide, and S9-treated benzo[a]pyrene, which activated unfolded protein response, and FTY720, lindane, and propanil, which activated the cholesterol biosynthesis pathway. In addition, processes uniquely affected by individual immunotoxicants were identified, such as the induction of Notch receptor signaling and the downregulation of acute-phase response genes by OTA. These findings were validated by quantitative real-time PCR analysis of genes involved in these processes. Our study indicated that diverse modes of action are involved in direct immunotoxicity and that a set of pathways or genes, rather than one single gene, can be used to screen compounds for direct immunotoxicity.

  9. Passive electronic dosimeters based on direct ion storage

    International Nuclear Information System (INIS)

    Kahilainen, J.

    1995-01-01

    Using non-volatile semiconductor memories as dosimeters in radiation protection is made possible by the application of the so-called DIS (Direct Ion Storage) method, where the charge collected from a small volume of gas is directly stored in a non-volatile memory cell. This allows the construction of small and simple electronic passive dosimeters with features not available in conventional passive Film or TLD dosimeters. The basic design principles and properties of DIS dosimeters are presented and the application potential for the measurement of various categories of ionizing radiation is discussed

  10. Conversion Disorder

    Directory of Open Access Journals (Sweden)

    Yacov Rofé

    2013-11-01

    Full Text Available Conversion disorder remains a mystery that has only become more complicated with the decline of the scientific status of psychoanalysis (e.g., Piper, Lillevik, & Kritzer, 2008; Rofé, 2008 and recent neurological findings suggest that this behavior is controlled by biological mechanisms (van Beilen, Vogt, & Leenders, 2010. Moreover, existing theories have difficulty explaining the efficacy of various interventions, such as psychoanalysis, behavior therapy, drug therapy and religious therapy. This article reviews research and clinical evidence pertaining to both the development and treatment of conversion disorder and shows that this seemingly incompatible evidence can be integrated within a new theory, the Rational-Choice Theory of Neurosis (RCTN; Rofé, 2010. Despite the striking differences, RCTN continues Freud's framework of thinking as it employs a new concept of repression and replaces the unconscious with self-deception. Moreover, it incorporates Freud's idea, implicitly expressed in his theory, that neurotic disorders are, in fact, rational behaviors.

  11. Cross-phase-modulation-based wavelength conversion using intersubband transition in InGaAs/AlAs/AlAsSb coupled quantum wells.

    Science.gov (United States)

    Tsuchida, Hidemi; Simoyama, Takasi; Ishikawa, Hiroshi; Mozume, Teruo; Nagase, Masanori; Kasai, Jun-ichi

    2007-04-01

    We report an ultrafast cross phase modulation (XPM) effect in intersubband transition (ISBT) of InGaAs/AlAs/AlAsSb coupled quantum wells, where the ISBT absorption of a transverse-magnetic mode pump signal induces phase modulation of a transverse-electric mode probe signal. Using waveguide-type ISBT devices, we have achieved XPM-based 10 Gbit/s wavelength conversion with a power penalty of 2.53 dB. Also, we propose XPM-based signal processing circuits for gate switching and modulation format conversion.

  12. Conjugated Polymers Via Direct Arylation Polymerization in Continuous Flow: Minimizing the Cost and Batch-to-Batch Variations for High-Throughput Energy Conversion

    DEFF Research Database (Denmark)

    Gobalasingham, Nemal S.; Carlé, Jon Eggert; Krebs, Frederik C

    2017-01-01

    of high-performance materials. To demonstrate the usefulness of the method, DArP-prepared PPDTBT via continuous flow synthesis is employed for the preparation of indium tin oxide (ITO)-free and flexible roll-coated solar cells to achieve a power conversion efficiency of 3.5% for 1 cm2 devices, which...... is comparable to the performance of PPDTBT polymerized through Stille cross coupling. These efforts demonstrate the distinct advantages of the continuous flow protocol with DArP avoiding use of toxic tin chemicals, reducing the associated costs of polymer upscaling, and minimizing batch-to-batch variations...

  13. Direct Observation vs. Video-Based Assessment in Flexible Cystoscopy

    DEFF Research Database (Denmark)

    Dagnaes-Hansen, Julia; Mahmood, Oria; Bube, Sarah

    2018-01-01

    observer and subsequently by 2 blinded video-raters on a global rating scale (GRS) for cystoscopy. Both intrarater and interrater reliability were explored. Furthermore, direct observer bias was explored by a paired samples t-test. RESULTS: Intrarater reliability calculated by Pearson's r was 0...

  14. Enhanced power conversion efficiency in InGaN-based solar cells via graded composition multiple quantum wells.

    Science.gov (United States)

    Tsai, Yu-Lin; Wang, Sheng-Wen; Huang, Jhih-Kai; Hsu, Lung-Hsing; Chiu, Ching-Hsueh; Lee, Po-Tsung; Yu, Peichen; Lin, Chien-Chung; Kuo, Hao-Chung

    2015-11-30

    This work demonstrates the enhanced power conversion efficiency (PCE) in InGaN/GaN multiple quantum well (MQWs) solar cells with gradually decreasing indium composition in quantum wells (GQWs) toward p-GaN as absorber. The GQW can improve the fill factor from 42% to 62% and enhance the short current density from 0.8 mA/cm2 to 0.92 mA/cm2, as compares to the typical MQW solar cells. As a result, the PCE is boosted from 0.63% to 1.11% under AM1.5G illumination. Based on simulation and experimental results, the enhanced PCE can be attributed to the improved carrier collection in GQW caused by the reduction of potential barriers and piezoelectric polarization induced fields near the p-GaN layer. The presented concept paves a way toward highly efficient InGaN-based solar cells and other GaN-related MQW devices.

  15. Imidazolium- and Triazine-Based Porous Organic Polymers for Heterogeneous Catalytic Conversion of CO2 into Cyclic Carbonates.

    Science.gov (United States)

    Zhong, Hong; Su, Yanqing; Chen, Xingwei; Li, Xiaoju; Wang, Ruihu

    2017-12-22

    CO 2 adsorption and concomitant catalytic conversion into useful chemicals are promising approaches to alleviate the energy crisis and effects of global warming. This is highly desirable for developing new types of heterogeneous catalytic materials containing CO 2 -philic groups and catalytic active sites for CO 2 chemical transformation. Here, we present an imidazolium- and triazine-based porous organic polymer with counter chloride anion (IT-POP-1). The porosity and CO 2 affinity of IT-POP-1 may be modulated at the molecular level through a facile anion-exchange strategy. Compared with the post-modified polymers with iodide and hexafluorophosphate anions, IT-POP-1 possesses the highest surface area and the best CO 2 uptake capacity with excellent adsorption selectivity over N 2 . The roles of the task-specific components such as triazine, imidazolium, hydroxyl, and counter anions in CO 2 absorption and catalytic performance were illustrated. IT-POP-1 exhibits the highest catalytic activity and excellent recyclability in solvent- and additive-free cycloaddition reaction of CO 2 with epoxides. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. High conversion of sugarcane bagasse into monosaccharides based on sodium hydroxide pretreatment at low water consumption and wastewater generation.

    Science.gov (United States)

    Wang, Wen; Wang, Qiong; Tan, Xuesong; Qi, Wei; Yu, Qiang; Zhou, Guixiong; Zhuang, Xinshu; Yuan, Zhenhong

    2016-10-01

    The generation of a great quantity of black liquor (BL) and waste wash water (WWW) has been key problems of the alkaline pretreatment. This work tried to build a sustainable way to recycle the BL for pretreating sugarcane bagasse (SCB) and the WWW for washing the residual solid (RS) of alkali-treated SCB which would be subsequently hydrolysed and fermented. The enzymatic hydrolysis efficiency of the washed RS decreased with the recycling times of BL and WWW increasing. Tween80 at the loading of 0.25% (V/V) could notably improve the enzymatic hydrolysis and had no negative impact on the downstream fermentation. Compared with the non-recycling and BL recycling ways based on alkaline pretreatment, the BL-WWW recycling way could not only maintain high conversion of carbohydrate into monosaccharides and save alkali amount of 45.5%, but also save more than 80% water and generate less than 15% waste water. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Degree of conversion and hardness of a silorane-based composite resin: effect of light-curing unit and depth.

    Science.gov (United States)

    Torres, S A S; Silva, G C; Maria, D A; Campos, W R C; Magalhães, C S; Moreira, A N

    2014-01-01

    To investigate the effect of different light-curing units and depths on the degree of conversion (DC) through Fourier transform infrared spectroscopy (FTIR) and Knoop Hardness Number (KHN) of a silorane-based composite resin (Filtek LS, 3M ESPE, St Paul, MN, USA) (LS). LS specimens mounted in a particular designed matrix were photoactivated by three light-cure units (LCUs) at depths of 2, 3, 4, and 5 mm. The DC was determined in a FTIR spectrometer with an attenuated total reflectance accessory. The KHN was measured in an automatic microhardness tester. The results were analyzed using the Friedman and Spearman statistical tests (α=0.05). There was no effect of LCUs on the DC (p=0.472) or KHN (p=0.174) for all of the studied depths. The highest DC and KHN means were found at 2-mm depth, which were not statistically different from 3-mm depth, but were higher than 4-mm and 5-mm depths (p=0.007). Spearman analysis found a positive linear correlation between the variables KHN and DC (r=0.858, p<0.000). The LCUs' effect was not verified. Values of DC and KHN for LS decreased with increasing depth. The highest values for both DC and KHN were obtained at depths of 2-3 mm.

  18. Stochastic Model Predictive Fault Tolerant Control Based on Conditional Value at Risk for Wind Energy Conversion System

    Directory of Open Access Journals (Sweden)

    Yun-Tao Shi

    2018-01-01

    Full Text Available Wind energy has been drawing considerable attention in recent years. However, due to the random nature of wind and high failure rate of wind energy conversion systems (WECSs, how to implement fault-tolerant WECS control is becoming a significant issue. This paper addresses the fault-tolerant control problem of a WECS with a probable actuator fault. A new stochastic model predictive control (SMPC fault-tolerant controller with the Conditional Value at Risk (CVaR objective function is proposed in this paper. First, the Markov jump linear model is used to describe the WECS dynamics, which are affected by many stochastic factors, like the wind. The Markov jump linear model can precisely model the random WECS properties. Second, the scenario-based SMPC is used as the controller to address the control problem of the WECS. With this controller, all the possible realizations of the disturbance in prediction horizon are enumerated by scenario trees so that an uncertain SMPC problem can be transformed into a deterministic model predictive control (MPC problem. Finally, the CVaR object function is adopted to improve the fault-tolerant control performance of the SMPC controller. CVaR can provide a balance between the performance and random failure risks of the system. The Min-Max performance index is introduced to compare the fault-tolerant control performance with the proposed controller. The comparison results show that the proposed method has better fault-tolerant control performance.

  19. Lead paste recycling based on conversion into battery grade oxides. Electrochemical tests and industrial production of new batteries

    Science.gov (United States)

    Fusillo, G.; Rosestolato, D.; Scura, F.; Cattarin, S.; Mattarozzi, L.; Guerriero, P.; Gambirasi, A.; Brianese, N.; Staiti, P.; Guerriero, R.; La Sala, G.

    2018-03-01

    We present the preparation and characterization of pure lead monoxide obtained through recycling of the lead paste recovered from exhausted lead acid batteries. The recycling is based on a hydrometallurgical procedure reported in a STC Patent, that includes simple chemical operations (desulphurisation, leaching, precipitation, filtration) and a final thermal conversion. Materials obtained by treatment at 600 °C consist predominantly of β-PbO. The electrochemical behaviour of Positive Active Mass (PAM) prepared from different materials (or mixtures) is then investigated and compared. An optimized oxide material, obtained by prolonged (8 h) thermal treatment at 600 °C, consists of pure β-PbO and appears suitable for preparation of battery elements, alone or in mixture with a small fraction (10%-30%) of traditional industrial leady oxide. The resulting battery performances are similar to those obtained from pure leady oxide. In comparison with traditional recycling processes, the proposed method guarantees lower energy consumption, limited environmental impact and reduced operating risk for industry workers.

  20. Dose Conversion Coefficients Based on Taiwanese Reference Phantoms and Monte Carlo Simulations for Use in External Radiation Protection.

    Science.gov (United States)

    Chang, Shu-Jun; Hsu, Jui-Ting; Hung, Shih-Yen; Liu, Yan-Lin; Jiang, Shiang-Huei; Wu, Jay

    2017-05-01

    Reference phantoms are widely applied to evaluate the radiation dose for external exposure. However, the frequently used reference phantoms are based on Caucasians. Dose estimation for Asians using a Caucasian phantom can result in significant errors. This study recruited 40 volunteers whose body sizes are close to the average Taiwanese population. Magnetic resonance imaging was performed to obtain the organ volume for construction of the Taiwanese reference man (TRM) and Taiwanese reference woman (TRW). The dose conversion coefficients (DCC) resulting from photo beams in anterior-posterior, posterior-anterior, right-lateral, left-lateral, and isotropic irradiation geometries were estimated. In the anterior-posterior geometry, the mean DCC differences among organs between the TRM and ORNL phantom at 0.1, 1, and 10 MeV were 7.3%, 5.8%, and 5.2%, respectively. For the TRW, the mean differences from the ORNL phantom at the three energies were 10.6%, 7.4%, and 8.3%. The DCCs of the Taiwanese reference phantoms and the ORNL phantom presented similar trends in other geometries. The torso size of the phantom and the mass and geometric location of the organ have a significant influence on the DCC. The Taiwanese reference phantoms can be used to establish dose guidelines and regulations for radiation protection from external exposure.

  1. Directed energy deflection laboratory measurements of common space based targets

    Science.gov (United States)

    Brashears, Travis; Lubin, Philip; Hughes, Gary B.; Meinhold, Peter; Batliner, Payton; Motta, Caio; Madajian, Jonathan; Mercer, Whitaker; Knowles, Patrick

    2016-09-01

    We report on laboratory studies of the effectiveness of directed energy planetary defense as a part of the DE-STAR (Directed Energy System for Targeting of Asteroids and exploRation) program. DE-STAR and DE-STARLITE are directed energy "stand-off" and "stand-on" programs, respectively. These systems consist of a modular array of kilowatt-class lasers powered by photovoltaics, and are capable of heating a spot on the surface of an asteroid to the point of vaporization. Mass ejection, as a plume of evaporated material, creates a reactionary thrust capable of diverting the asteroid's orbit. In a series of papers, we have developed a theoretical basis and described numerical simulations for determining the thrust produced by material evaporating from the surface of an asteroid. In the DESTAR concept, the asteroid itself is used as the deflection "propellant". This study presents results of experiments designed to measure the thrust created by evaporation from a laser directed energy spot. We constructed a vacuum chamber to simulate space conditions, and installed a torsion balance that holds a common space target sample. The sample is illuminated with a fiber array laser with flux levels up to 60 MW/m2 , which allows us to simulate a mission level flux but on a small scale. We use a separate laser as well as a position sensitive centroid detector to readout the angular motion of the torsion balance and can thus determine the thrust. We compare the measured thrust to the models. Our theoretical models indicate a coupling coefficient well in excess of 100 μN/Woptical, though we assume a more conservative value of 80 μN/Woptical and then degrade this with an optical "encircled energy" efficiency of 0.75 to 60 μN/Woptical in our deflection modeling. Our measurements discussed here yield about 45 μN/Wabsorbed as a reasonable lower limit to the thrust per optical watt absorbed. Results vary depending on the material tested and are limited to measurements of 1 axis, so

  2. Towards 15% energy conversion efficiency: a systematic study of the solution-processed organic tandem solar cells based on commercially available materials

    DEFF Research Database (Denmark)

    Li, Ning; Baran, Derya; Forberich, Karen

    2013-01-01

    in organic tandem solar cells. All the devices are processed under environmental conditions using doctor-blading, which is highly compatible with mass-production coating technologies. Power conversion efficiencies (PCE) of 6–7% are obtained for OPV devices based on different active layers. Optical...

  3. Biomass valorisation by staged degasification A new pyrolysis-based thermochemical conversion option to produce value-added chemicals from lignocellulosic biomass

    NARCIS (Netherlands)

    de Wild, P. J.; den Uil, H.; Reith, J. H.; Kiel, J. H. A.; Heeres, H. J.

    Pyrolysis of lignocellulosic biomass leads to an array Of useful solid, liquid and gaseous products. Staged degasification is a pyrolysis-based conversion route to generate value-added chemicals from biomass. Because of different thermal stabilities of the main biomass constituents hemicellulose.

  4. Tunable All-Optical Wavelength Conversion Based on Cascaded SHG/DFG in a Ti:PPLN Waveguide Using a Single CW Control Laser

    DEFF Research Database (Denmark)

    Hu, Hao; Nouroozi, Rahman; Wang, Wenrui

    2012-01-01

    Tunable all-optical wavelength conversion (AOWC) of a 40-Gb/s RZ-OOK data signal based on cascaded second-harmonic generation (SHG) and difference-frequency generation (DFG) in a Ti:PPLN waveguide is demonstrated. Error-free performances with negligible power penalty are achieved for the wavelength...

  5. Effects of a Conversation-Based Intervention on the Linguistic Skills of Children with Motor Speech Disorders Who Use Augmentative and Alternative Communication

    Science.gov (United States)

    Soto, Gloria; Clarke, Michael T.

    2017-01-01

    Purpose: This study was conducted to evaluate the effects of a conversation-based intervention on the expressive vocabulary and grammatical skills of children with severe motor speech disorders and expressive language delay who use augmentative and alternative communication. Method: Eight children aged from 8 to 13 years participated in the study.…

  6. DIRECT GEOREFERENCING OF UAV DATA BASED ON SIMPLE BUILDING STRUCTURES

    Directory of Open Access Journals (Sweden)

    W. Tampubolon

    2016-06-01

    Full Text Available Unmanned Aerial Vehicle (UAV data acquisition is more flexible compared with the more complex traditional airborne data acquisition. This advantage puts UAV platforms in a position as an alternative acquisition method in many applications including Large Scale Topographical Mapping (LSTM. LSTM, i.e. larger or equal than 1:10.000 map scale, is one of a number of prominent priority tasks to be solved in an accelerated way especially in third world developing countries such as Indonesia. As one component of fundamental geospatial data sets, large scale topographical maps are mandatory in order to enable detailed spatial planning. However, the accuracy of the products derived from the UAV data are normally not sufficient for LSTM as it needs robust georeferencing, which requires additional costly efforts such as the incorporation of sophisticated GPS Inertial Navigation System (INS or Inertial Measurement Unit (IMU on the platform and/or Ground Control Point (GCP data on the ground. To reduce the costs and the weight on the UAV alternative solutions have to be found. This paper outlines a direct georeferencing method of UAV data by providing image orientation parameters derived from simple building structures and presents results of an investigation on the achievable results in a LSTM application. In this case, the image orientation determination has been performed through sequential images without any input from INS/IMU equipment. The simple building structures play a significant role in such a way that geometrical characteristics have been considered. Some instances are the orthogonality of the building’s wall/rooftop and the local knowledge of the building orientation in the field. In addition, we want to include the Structure from Motion (SfM approach in order to reduce the number of required GCPs especially for the absolute orientation purpose. The SfM technique applied to the UAV data and simple building structures additionally presents an

  7. Optimization of Orchestral Layouts Based on Instrument Directivity Patterns

    Science.gov (United States)

    Stroud, Nathan Paul

    The experience of hearing an exceptional symphony orchestra perform in an excel- lent concert hall can be profound and moving, causing a level of excitement not often reached for listeners. Romantic period style orchestral music, recognized for validating the use of intense emotion for aesthetic pleasure, was the last significant development in the history of the orchestra. In an age where orchestral popularity is waning, the possibil- ity of evolving the orchestral sound in our modern era exists through the combination of our current understanding of instrument directivity patterns and their interaction with architectural acoustics. With the aid of wave field synthesis (WFS), newly proposed variations on orchestral layouts are tested virtually using a 64-channel WFS array. Each layout is objectively and subjectively compared for determination of which layout could optimize the sound of the orchestra and revitalize the excitement of the performance.

  8. Direct Reconstruction of CT-based Attenuation Correction Images for PET with Cluster-Based Penalties

    Science.gov (United States)

    Kim, Soo Mee; Alessio, Adam M.; De Man, Bruno; Asma, Evren; Kinahan, Paul E.

    2015-01-01

    Extremely low-dose CT acquisitions for the purpose of PET attenuation correction will have a high level of noise and biasing artifacts due to factors such as photon starvation. This work explores a priori knowledge appropriate for CT iterative image reconstruction for PET attenuation correction. We investigate the maximum a posteriori (MAP) framework with cluster-based, multinomial priors for the direct reconstruction of the PET attenuation map. The objective function for direct iterative attenuation map reconstruction was modeled as a Poisson log-likelihood with prior terms consisting of quadratic (Q) and mixture (M) distributions. The attenuation map is assumed to have values in 4 clusters: air+background, lung, soft tissue, and bone. Under this assumption, the MP was a mixture probability density function consisting of one exponential and three Gaussian distributions. The relative proportion of each cluster was jointly estimated during each voxel update of direct iterative coordinate decent (dICD) method. Noise-free data were generated from NCAT phantom and Poisson noise was added. Reconstruction with FBP (ramp filter) was performed on the noise-free (ground truth) and noisy data. For the noisy data, dICD reconstruction was performed with the combination of different prior strength parameters (β and γ) of Q- and M-penalties. The combined quadratic and mixture penalties reduces the RMSE by 18.7% compared to post-smoothed iterative reconstruction and only 0.7% compared to quadratic alone. For direct PET attenuation map reconstruction from ultra-low dose CT acquisitions, the combination of quadratic and mixture priors offers regularization of both variance and bias and is a potential method to derive attenuation maps with negligible patient dose. However, the small improvement in quantitative accuracy relative to the substantial increase in algorithm complexity does not currently justify the use of mixture-based PET attenuation priors for reconstruction of CT

  9. Selective Dielectric Metasurfaces Based on Directional Conditions of Silicon Nanopillars.

    Science.gov (United States)

    Algorri, José Francisco; García-Cámara, Braulio; Cuadrado, Alexander; Sánchez-Pena, José Manuel; Vergaz, Ricardo

    2017-07-07

    Dielectric metasurfaces based on high refractive index materials have been proposed recently. This type of structure has several advantages over their metallic counterparts. In this work, we demonstrate that dielectric metasurfaces can be theoretically designed satisfying Kerker's zero-forward condition. This is the first time that a dielectric metasurface based on this principle has been designed. A selective dielectric metasurface of silicon nanopillars is designed to work at 632.8 nm. This structure could work both as a dielectric mirror and a reject band filter. Furthermore, by scaling up the structure, it could be possible to manufacture a terahertz (THz) dielectric mirror.

  10. Dynamically reconfigurable directionality of plasmon-based single photon sources

    DEFF Research Database (Denmark)

    Chen, Yuntian; Lodahl, Peter; Koenderink, A. Femius

    2010-01-01

    We propose a plasmon-based reconfigurable antenna to controllably distribute emission from single quantum emitters in spatially separated channels. Our calculations show that crossed particle arrays can split the stream of photons from a single emitter into multiple narrow beams. We predict...... that beams can be switched on and off by switching host refractive index. The design method is based on engineering the dispersion relations of plasmon chains and is generally applicable to traveling wave antennas. Controllable photon delivery has potential applications in classical and quantum communication....

  11. Reality-Based Genre Preferences Do Not Direct Personal Involvement

    Science.gov (United States)

    Konijn, Elly A.; Hoorn, Johan F.

    2004-01-01

    Although it seems plausible that people who prefer a particular genre would appreciate characters from that category more than those from other genres, this appears not to be the case. We devised a parsimonious reality-based genre taxonomy that differentiates nonfiction, realism, fantasy, and humor. In Study 1, evidence from film viewers' genre…

  12. Directional wavelet based features for colonic polyp classification.

    Science.gov (United States)

    Wimmer, Georg; Tamaki, Toru; Tischendorf, J J W; Häfner, Michael; Yoshida, Shigeto; Tanaka, Shinji; Uhl, Andreas

    2016-07-01

    In this work, various wavelet based methods like the discrete wavelet transform, the dual-tree complex wavelet transform, the Gabor wavelet transform, curvelets, contourlets and shearlets are applied for the automated classification of colonic polyps. The methods are tested on 8 HD-endoscopic image databases, where each database is acquired using different imaging modalities (Pentax's i-Scan technology combined with or without staining the mucosa), 2 NBI high-magnification databases and one database with chromoscopy high-magnification images. To evaluate the suitability of the wavelet based methods with respect to the classification of colonic polyps, the classification performances of 3 wavelet transforms and the more recent curvelets, contourlets and shearlets are compared using a common framework. Wavelet transforms were already often and successfully applied to the classification of colonic polyps, whereas curvelets, contourlets and shearlets have not been used for this purpose so far. We apply different feature extraction techniques to extract the information of the subbands of the wavelet based methods. Most of the in total 25 approaches were already published in different texture classification contexts. Thus, the aim is also to assess and compare their classification performance using a common framework. Three of the 25 approaches are novel. These three approaches extract Weibull features from the subbands of curvelets, contourlets and shearlets. Additionally, 5 state-of-the-art non wavelet based methods are applied to our databases so that we can compare their results with those of the wavelet based methods. It turned out that extracting Weibull distribution parameters from the subband coefficients generally leads to high classification results, especially for the dual-tree complex wavelet transform, the Gabor wavelet transform and the Shearlet transform. These three wavelet based transforms in combination with Weibull features even outperform the state

  13. Assessing distractors and teamwork during surgery: developing an event-based method for direct observation.

    Science.gov (United States)

    Seelandt, Julia C; Tschan, Franziska; Keller, Sandra; Beldi, Guido; Jenni, Nadja; Kurmann, Anita; Candinas, Daniel; Semmer, Norbert K

    2014-11-01

    To develop a behavioural observation method to simultaneously assess distractors and communication/teamwork during surgical procedures through direct, on-site observations; to establish the reliability of the method for long (>3 h) procedures. Observational categories for an event-based coding system were developed based on expert interviews, observations and a literature review. Using Cohen's κ and the intraclass correlation coefficient, interobserver agreement was assessed for 29 procedures. Agreement was calculated for the entire surgery, and for the 1st hour. In addition, interobserver agreement was assessed between two tired observers and between a tired and a non-tired observer after 3 h of surgery. The observational system has five codes for distractors (door openings, noise distractors, technical distractors, side conversations and interruptions), eight codes for communication/teamwork (case-relevant communication, teaching, leadership, problem solving, case-irrelevant communication, laughter, tension and communication with external visitors) and five contextual codes (incision, last stitch, personnel changes in the sterile team, location changes around the table and incidents). Based on 5-min intervals, Cohen's κ was good to excellent for distractors (0.74-0.98) and for communication/teamwork (0.70-1). Based on frequency counts, intraclass correlation coefficient was excellent for distractors (0.86-0.99) and good to excellent for communication/teamwork (0.45-0.99). After 3 h of surgery, Cohen's κ was 0.78-0.93 for distractors, and 0.79-1 for communication/teamwork. The observational method developed allows a single observer to simultaneously assess distractors and communication/teamwork. Even for long procedures, high interobserver agreement can be achieved. Data collected with this method allow for investigating separate or combined effects of distractions and communication/teamwork on surgical performance and patient outcomes. Published by the

  14. An Improved Direction Finding Algorithm Based on Toeplitz Approximation

    Directory of Open Access Journals (Sweden)

    Qing Wang

    2013-01-01

    Full Text Available In this paper, a novel direction of arrival (DOA estimation algorithm called the Toeplitz fourth order cumulants multiple signal classification method (TFOC-MUSIC algorithm is proposed through combining a fast MUSIC-like algorithm termed the modified fourth order cumulants MUSIC (MFOC-MUSIC algorithm and Toeplitz approximation. In the proposed algorithm, the redundant information in the cumulants is removed. Besides, the computational complexity is reduced due to the decreased dimension of the fourth-order cumulants matrix, which is equal to the number of the virtual array elements. That is, the effective array aperture of a physical array remains unchanged. However, due to finite sampling snapshots, there exists an estimation error of the reduced-rank FOC matrix and thus the capacity of DOA estimation degrades. In order to improve the estimation performance, Toeplitz approximation is introduced to recover the Toeplitz structure of the reduced-dimension FOC matrix just like the ideal one which has the Toeplitz structure possessing optimal estimated results. The theoretical formulas of the proposed algorithm are derived, and the simulations results are presented. From the simulations, in comparison with the MFOC-MUSIC algorithm, it is concluded that the TFOC-MUSIC algorithm yields an excellent performance in both spatially-white noise and in spatially-color noise environments.

  15. Enhancing base station connectivity with directional information of movement

    Directory of Open Access Journals (Sweden)

    Eugene Kim

    2016-09-01

    Full Text Available High-performance smartphones with various sensor capabilities, including the inertial measurement unit, allow us to have higher freedom to localize our movements and utilize them for other applications. In this paper, we present a simple method to estimate the heading of a user using only a digital compass, accelerometer, and gyroscope. Several experiments were conducted using an Apple iPhone. In addition, we also present an algorithm to reduce the number of handover attempts in a dense base station environment. A series of simulations were conducted on OPNET in various emulated environments to present the effectiveness of the proposed method. The simulation results show that our proposed algorithm effectively reduces the ping-pong effect in a dense base station environment.

  16. Mass spectrometry-based proteomics: existing capabilities and future directions

    Energy Technology Data Exchange (ETDEWEB)

    Angel, Thomas E.; Aryal, Uma K.; Hengel, Shawna M.; Baker, Erin Shammel; Kelly, Ryan T.; Robinson, Errol W.; Smith, Richard D.

    2012-05-21

    Mass spectrometry-based proteomics provides a means for identification, characterization, and quantification of biomolecules that are integral components of the processes essential for life. Characterization of proteins present in a biological system at the proteome and sub-proteomes (e.g., the phosphoproteome, proteoglycome, or degradome/peptidome) levels provides a foundation for understanding fundamental aspects as well as potentially a range of translational applications. Emerging technologies such as ion mobility separations coupled with mass spectrometry and microchip-based - proteome measurements combined with continued enhancement of MS instrumentation and separation techniques, such as reversed phase liquid chromatography and potentially capillary electrophoresis, show great promise for both broad undirected as well as targeted measurements and will be critical for e.g., the proteome-wide characterization of post translational modifications and identification, or the verification, and validation of potential biomarkers of disease. MS-based proteomics is also increasingly demonstrating great potential for contributing to our understanding of the dynamics, reactions, and roles proteins and peptides play advancing our understanding of biology on a system wide level for a wide range of applications, from investigations of microbial communities, bioremediation, and human health and disease states alike.

  17. Olfactory impairment and subjective olfactory complaints independently predict conversion to dementia: a longitudinal, population-based study.

    Science.gov (United States)

    Stanciu, Ingrid; Larsson, Maria; Nordin, Steven; Adolfsson, Rolf; Nilsson, Lars-Göran; Olofsson, Jonas K

    2014-02-01

    We examined whether conversion to dementia can be predicted by self-reported olfactory impairment and/or by an inability to identify odors. Common forms of dementia involve an impaired sense of smell, and poor olfactory performance predicts cognitive decline among the elderly. We followed a sample of 1529 participants, who were within a normal range of overall cognitive function at baseline, over a 10-year period during which 159 were classified as having a dementia disorder. Dementia conversion was predicted from demographic variables, Mini-Mental State Examination score, and olfactory assessments. Self-reported olfactory impairment emerged as an independent predictor of dementia. After adjusting for effects of other predictors, individuals who rated their olfactory sensitivity as "worse than normal" were more likely to convert to dementia than those who reported normal olfactory sensitivity (odds ratio [OR] = 2.17; 95% confidence interval [CI] [1.40, 3.37]). Additionally, low scores on an odor identification test also predicted conversion to dementia (OR per 1 point increase = 0.89; 95% CI [0.81, 0.98]), but these two effects were additive. We suggest that assessing subjective olfactory complaints might supplement other assessments when evaluating the risk of conversion to dementia. Future studies should investigate which combination of olfactory assessments is most useful in predicting dementia conversion.

  18. Kinetics of the development of a nonchromate conversion coating for magnesium alloys and magnesium-based metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Nunez, M.A.; Skeldon, P.; Thompson, G.E.; Karimzadeh, H.

    1999-12-01

    Kinetics of the development of a conversion coating from a stannate bath on commercial purity magnesium (Mg{sup comm}), magnesium-based alloys ZC71 and WE43, and a metal matrix composite (MMC), comprising a ZC71 alloy matrix and 12 vol% silicon carbide (SiC) particles were studied using linear polarization resistance, potential-time, potentiodynamic polarization, x-ray diffraction, Rutherford backscattering spectroscopy, and microscopic examination. The coating, typically {approximately}3 {micro}m to 5 {micro}m thick, was composed largely of crystalline magnesium tin oxide (MgSnO{sub 3} {center{underscore}dot} 3H{sub 2}O), and developed by a nucleation and growth process through an initial corrosion film on the substrate. Nucleation probably occurred on regions where a critical concentration of magnesium ions was reached for coating crystals to form. Specific sites of nucleation, such as particles of eutectic phase and of reinforcement, were revealed in some cases, but frequently the precise sites of nucleation were not disclosed. A longer treatment time (at least 35 min) was suggested by polarization resistance data for improved coverage of the substrate than the previously recommended time of 20 min. The coating continuity on the substrates, after a particular time of treatment, depends upon ally composition increasing in order: Mg{sup comm}, 12% (SiC)p/ZC71 alloy MMC, ZC71 alloy, and WE43 alloy. Polarization resistance (R{sub p}) changed systematically with coating development, showing a decrease in R{sub p} in the early stages of the coating process, related to the initial corrosion.

  19. Degree of conversion and microhardness of TPO-containing resin-based composites cured by polywave and monowave LED units.

    Science.gov (United States)

    Santini, Ario; Miletic, Vesna; Swift, Michael D; Bradley, Mark

    2012-07-01

    To determine the degree of conversion (DC) and Knoop microhardness (KHN) of resin-based composites (RBCs) containing trimethylbenzoyl-diphenylphosphine oxide (TPO) cured by polywave or monowave LED light-curing units (LCUs). Three groups (each n = 5) of Tetric EvoCeram (Ivoclar Vivadent), Vit-l-escence (Ultradent) and Herculite XRV Ultra (Kerr) were prepared in Teflon moulds (5mm in diameter and 2mm thick) and cured with polywave Bluephase(®) G2 (Ivoclar Vivadent), polywave Valo (Ultradent) or monowave Bluephase(®) (Ivoclar Vivadent; control) resulting in 9 groups. DC and KHN were determined using micro-Raman spectroscopy and Knoop microhardness, respectively. High-performance liquid chromatography and nuclear magnetic resonance spectroscopy were used to confirm the presence or absence of TPO in the three uncured materials. Data were statistically analysed using two-way and one-way ANOVA and DC and KHN were correlated using Pearson's correlation (α = 0.05). TPO was confirmed in Tetric EvoCeram and Vit-l-escence but not in Herculite XRV Ultra. All three LCUs produced comparable KHN for Tetric EvoCeram and Herculite XRV Ultra (p > 0.05). Both polywave LCUs resulted in significantly higher KHN for Vit-l-escence and higher DC in Tetric EvoCeram and Vit-l-escence than the monowave Bluephase(®) (p TPO-containing RBCs, but not in Herculite XRV Ultra. DC and KHN were linearly correlated in all three RBCs. Vit-l-escence showed the highest DC and KHN of the three materials tested. The use of polywave LEDs significantly improves both the DC and KHN of materials which contain TPO. This should be taken into account when curing bleached shades of RBCs even if the manufacturers do not indicate the presence of TPO in their materials. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Advanced-fueled fusion reactors suitable for direct energy conversion. Project note: temperature-gradient enhancement of electrical fields in insulators

    International Nuclear Information System (INIS)

    Blum, A.S.; Mancebo, L.

    1976-01-01

    Direct energy converters for use on controlled fusion reactors utilize electrodes operated at elevated voltages and temperatures. The insulating elements that position these electrodes must support large voltages and under some circumstances large thermal gradients. It is shown that even modest thermal gradients can cause major alterations of the electric-field distribution within the insulating element

  1. A New Generalized Two-Stage Direct Power Conversion Topology to Independently Supply Multiple AC Loads from Multiple Power Grids with Adjustable Power Loading

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede

    2004-01-01

    ) and continuously adjust these power fractions will become a desired feature. This paper presents a generalized Direct Power Converter topology, which is able to connect to multiple AC supplies proving complete decoupling and no circulating power between the input ports and to independently control multiple AC...

  2. Uncertain rule-based fuzzy systems introduction and new directions

    CERN Document Server

    Mendel, Jerry M

    2017-01-01

    The second edition of this textbook provides a fully updated approach to fuzzy sets and systems that can model uncertainty — i.e., “type-2” fuzzy sets and systems. The author demonstrates how to overcome the limitations of classical fuzzy sets and systems, enabling a wide range of applications from time-series forecasting to knowledge mining to control. In this new edition, a bottom-up approach is presented that begins by introducing classical (type-1) fuzzy sets and systems, and then explains how they can be modified to handle uncertainty. The author covers fuzzy rule-based systems – from type-1 to interval type-2 to general type-2 – in one volume. For hands-on experience, the book provides information on accessing MatLab and Java software to complement the content. The book features a full suite of classroom material. Presents fully updated material on new breakthroughs in human-inspired rule-based techniques for handling real-world uncertainties; Allows those already familiar with type-1 fuzzy se...

  3. Individual based and mean-field modeling of direct aggregation

    KAUST Repository

    Burger, Martin

    2013-10-01

    We introduce two models of biological aggregation, based on randomly moving particles with individual stochasticity depending on the perceived average population density in their neighborhood. In the firstorder model the location of each individual is subject to a density-dependent random walk, while in the second-order model the density-dependent random walk acts on the velocity variable, together with a density-dependent damping term. The main novelty of our models is that we do not assume any explicit aggregative force acting on the individuals; instead, aggregation is obtained exclusively by reducing the individual stochasticity in response to higher perceived density. We formally derive the corresponding mean-field limits, leading to nonlocal degenerate diffusions. Then, we carry out the mathematical analysis of the first-order model, in particular, we prove the existence of weak solutions and show that it allows for measure-valued steady states. We also perform linear stability analysis and identify conditions for pattern formation. Moreover, we discuss the role of the nonlocality for well-posedness of the first-order model. Finally, we present results of numerical simulations for both the first- and second-order model on the individual-based and continuum levels of description. 2012 Elsevier B.V. All rights reserved.

  4. Model based, sensor directed remediation of underground storage tanks

    International Nuclear Information System (INIS)

    Christensen, B.; Drotning, W.; Thunborg, S.

    1991-01-01

    Sensor rich, intelligent robots which function with respect to models of their environment have significant potential to reduce the time and cost for the cleanup of hazardous waste while increasing operator safety. Sandia National Laboratories is performing experimental investigations into the application of intelligent robot control technology to the problem of removing waste stored tanks. This paper describes the experimental environment employed at Saudi with particular attention to the computing and software control environment. Intelligent system control is achieved though the integration of extensive geometric and kinematic world models with real-time sensor based control. All operator interactions with the system are validate all operator commands before execution to provide a safe operation. Sensing is used to add information to the robot system's world model and to allow sensor based sensor control during selected operations. The results of a first Critical Feature Test are reported and the potential for applying advanced intelligent control concepts to the removal of waste in storage tanks is discussed

  5. Photovoltaic solar energy conversion

    CERN Document Server

    Bauer, Gottfried H

    2015-01-01

    This concise primer on photovoltaic solar energy conversion invites readers to reflect on the conversion of solar light into energy at the most fundamental level and encourages newcomers to the field to help find meaningful answers on how photovoltaic solar energy conversion can work (better), eventually contributing to its ongoing advancement. The book is based on lectures given to graduate students in the Physics Department at the University of Oldenburg over the last two decades, yet also provides an easy-to-follow introduction for doctoral and postdoctoral students from related disciplines such as the materials sciences and electrical engineering. Inspired by classic textbooks in the field, it reflects the author’s own ideas on how to understand, visualize and eventually teach the microscopic physical mechanisms and effects, while keeping the text as concise as possible so as to introduce interested readers to the field and balancing essential knowledge with open questions.

  6. Calculation of computed tomography dose index to effective dose conversion factors based on measurement of the dose profile along the fan shaped beam.

    Science.gov (United States)

    Jansen, J T; Geleijns, J; Zweers, D; Schultz, F W; Zoetelief, J

    1996-01-01

    The variation in computed tomography dose index (CTDI) to effective dose conversion factors between different types of CT scanner is large (i.e. a factor of about 2 due to differences in beam shaping filters). Consequently, scanner specific conversion factors have to be applied. For some types of scanner, however, detailed information on the construction of beam shaping filters is not provided by the manufacturers. It is of interest to investigate the use of measured dose profiles for the calculation of conversion factors. Based upon measured dose profiles, two appropriate photon spectra selected on the basis of measured half value layers, gender specific adult phantoms Adam and Eva, and the Monte Carlo neutron and photon radiation transport code (MCNP), organ and effective dose conversion factors are calculated. To validate the method, a comparison is made between results for measured and calculated beam profiles for a Philips Tomoscan 350. The results in terms of effective dose per slice per unit of CTDI are compared with published data. Relative difference in conversion factors per slice averaged over all slices used for the calculations is 13 +/- 4% between the two spectra, 10.2 +/- 0.2% between measured and calculated beam profiles and 50 +/- 191% between the phantoms of different gender. The relative difference between the averaged results for the Adam and Eva phantoms and published results for a hermaphrodite phantom is on average equal to or less than 15 +/- 13%, depending on the spectrum and beam profile used, although larger differences can occur for specific slices. It is concluded that CTDI to effective dose conversion factors can be derived on the basis of measured beam profiles.

  7. Prediction Model of Conversion to Dementia Risk in Subjects with Amnestic Mild Cognitive Impairment: A Longitudinal, Multi-Center Clinic-Based Study.

    Science.gov (United States)

    Jang, Hyemin; Ye, Byoung Seok; Woo, Sookyoung; Kim, Sun Woo; Chin, Juhee; Choi, Seong Hye; Jeong, Jee Hyang; Yoon, Soo Jin; Yoon, Bora; Park, Kyung Won; Hong, Yun Jeong; Kim, Hee Jin; Lockhart, Samuel N; Na, Duk L; Seo, Sang Won

    2017-01-01

    Patients with amnestic mild cognitive impairment (aMCI) have an increased risk of dementia. However, conversion rate varies. Therefore, predicting the dementia conversion in these patients is important. We aimed to develop a nomogram to predict dementia conversion in aMCI subjects using neuropsychological profiles. A total of 338 aMCI patients from two hospital-based cohorts were used in analysis. All patients were classified into 1) verbal, visual, or both, 2) early or late, and 3) single or multiple-domain aMCI according to the modality, severity of memory dysfunction, and multiplicity of involved cognitive domains, respectively. Patients were followed up, and conversion to dementia within 3 years was defined as the primary outcome. Our patients were divided into a training data set and a validation data set. The associations of potential covariates with outcome were tested, and nomogram was constructed by logistic regression model. We also developed another model with APOE data, which included 242 patients. In logistic regression models, both modalities compared with visual only (OR 4.44, 95% CI 1.83-10.75, p = 0.001), late compared to early (OR 2.59, 95% CI 1.17-5.72, p = 0.019), and multiple compared to single domain (OR 3.51, 95% CI 1.62-7.60, p = 0.002) aMCI were significantly associated with dementia conversion within 3 years. A nomogram incorporating these clinical variables was constructed on the training data set and validated on the validation data set. Both nomograms with and without APOE data showed good prediction performance (c-statistics ≥ 0.75). This study showed that several neuropsychological profiles of aMCI are significantly associated with imminent dementia conversion, and a nomogram incorporating these clinical subtypes is simple and useful to help to predict disease progression.

  8. Conversion and Validation of Distribution System Model from a QSTS-Based Tool to a Real-Time Dynamic Phasor Simulator

    Energy Technology Data Exchange (ETDEWEB)

    Chamana, Manohar; Prabakar, Kumaraguru; Palmintier, Bryan; Baggu, Murali M.

    2017-05-11

    A software process is developed to convert distribution network models from a quasi-static time-series tool (OpenDSS) to a real-time dynamic phasor simulator (ePHASORSIM). The description of this process in this paper would be helpful for researchers who intend to perform similar conversions. The converter could be utilized directly by users of real-time simulators who intend to perform software-in-the-loop or hardware-in-the-loop tests on large distribution test feeders for a range of use cases, including testing functions of advanced distribution management systems against a simulated distribution system. In the future, the developers intend to release the conversion tool as open source to enable use by others.

  9. Conversion and Validation of Distribution System Model from a QSTS-Based Tool to a Real-Time Dynamic Phasor Simulator: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Chamana, Manohar; Prabakar, Kumaraguru; Palmintier, Bryan; Baggu, Murali M.

    2017-04-11

    A software process is developed to convert distribution network models from a quasi-static time-series tool (OpenDSS) to a real-time dynamic phasor simulator (ePHASORSIM). The description of this process in this paper would be helpful for researchers who intend to perform similar conversions. The converter could be utilized directly by users of real-time simulators who intend to perform software-in-the-loop or hardware-in-the-loop tests on large distribution test feeders for a range of use cases, including testing functions of advanced distribution management systems against a simulated distribution system. In the future, the developers intend to release the conversion tool as open source to enable use by others.

  10. EnerGis: A geographical information based system for the evaluation of integrated energy conversion systems in urban areas

    International Nuclear Information System (INIS)

    Girardin, Luc; Marechal, Francois; Dubuis, Matthias; Calame-Darbellay, Nicole; Favrat, Daniel

    2010-01-01

    A geographical information system has been developed to model the energy requirements of an urban area. The purpose of the platform is to model with sufficient detail the energy services requirements of a given geographical area in order to allow the evaluation of the integration of advanced integrated energy conversion systems. This tool is used to study the emergence of more efficient cities that realize energy efficiency measures, integrate energy efficient conversion technologies and promote the use of endogenous renewable energy. The model is illustrated with case studies for the energetic planning of the Geneva district (Switzerland).

  11. Final Environmental Assessment, Conversion of Forest Land to Road Right-of-Way, Arnold Air Force Base, Tennessee

    Science.gov (United States)

    2005-04-01

    devorpmI-imeS tnerruC yradnuoB esaB 000,4000,3000,2000,10 teeF Wattendorf Memorial Hwy E012005024ATL\\Tree115.ai Figure 2-3 Conversion of Forest Land...devorpmI-imeS tnerruC 000,4000,3000,2000,10 teeF Wattendorf Memorial Hwy E012005024ATL\\Tree116.ai Figure 2-4 Conversion of Forest Land to Road Right-of...maples (Acer spp.), sassafras (Sassafras albidum), sourwood (Oxydendrum arboreum), and blueberries (Vaccinium spp.). 3.4.4 Sensitive Species

  12. Video in the Proficiency-Based Advanced Conversation Class: An Example from the Russian-Language Curriculum.

    Science.gov (United States)

    Rifkin, Benjamin

    2000-01-01

    Reviews research on proficiency levels attained by foreign language students, and describes an advanced Russian conversation course, which is geared toward students who have achieved intermediate-mid or intermediate-high oral proficiency and who are striving towards advanced level speech according to the American Council on the Teaching of Foreign…

  13. OTDM-to-WDM Conversion Based on Time-to-Frequency Mapping by Time-Domain Optical Fourier Transformation

    DEFF Research Database (Denmark)

    Palushani, Evarist; Mulvad, Hans Christian Hansen; Galili, Michael

    2012-01-01

    This paper reports on the utilization of the timedomain optical Fourier transformation (OFT) technique for serial-to-parallel conversion of optical time division multiplexed (OTDM) data tributaries into dense wavelength division multiplexed (DWDM) channels. The OFT is implemented by using...

  14. The effects of the use of a conversational model and opportunities for reflections in computer-based role playing

    NARCIS (Netherlands)

    Holsbrink-Engels, G.A.

    1997-01-01

    This study examined the effects of an instructional program on 21-year-old students' interpersonal skills development (N = 104). The HyperCard 2.1 program ¿Telling bad news¿ could contain a conversational model that informed students about the main moments and actions in conducting a bad-news

  15. Numerical study on flow fields and aerodynamics of tilt rotor aircraft in conversion mode based on embedded grid and actuator model

    Directory of Open Access Journals (Sweden)

    Ying Zhang

    2015-02-01

    Full Text Available A method combining rotor actuator disk model and embedded grid technique is presented in this paper, aimed at predicting the flow fields and aerodynamic characteristics of tilt rotor aircraft in conversion mode more efficiently and effectively. In this method, rotor’s influence is considered in terms of the momentum it impacts to the fluid around it; transformation matrixes among different coordinate systems are deduced to extend actuator method’s utility to conversion mode flow fields’ calculation. Meanwhile, an embedded grid system is designed, in which grids generated around fuselage and actuator disk are regarded as background grid and minor grid respectively, and a new method is presented for ‘donor searching’ and ‘hole cutting’ during grid assembling. Based on the above methods, flow fields of tilt rotor aircraft in conversion mode are simulated, with three-dimensional Navier–Stokes equations discretized by a second-order upwind finite-volume scheme and an implicit lower–upper symmetric Gauss–Seidel (LU-SGS time-stepping scheme. Numerical results demonstrate that the proposed CFD method is very effective in simulating the conversion mode flow fields of tilt rotor aircraft.

  16. The effect of surface pre-conditioning treatments on the local composition of Zr-based conversion coatings formed on aluminium alloys

    International Nuclear Information System (INIS)

    Cerezo, J.; Vandendael, I.; Posner, R.; Wit, J.H.W. de; Mol, J.M.C.; Terryn, H.

    2016-01-01

    Graphical abstract: - Highlights: • Field Emission Auger Electron Spectroscopy was used for local elemental analysis. • Acid and alkaline pre-conditioning treatments induces Cu-enrichment on AA6014. • A Cu-containing Zr-based conversion treatment for aluminium alloys was evaluated. • Cu-rich areas enhance the local formation of Zr-based conversion films on AA6014. • Thermal pre-conditioning treatments inhibits the formation of Zr-based coatings. - Abstract: This study investigates the effect of different alkaline, acidic and thermal pre-conditioning treatments applied to different Al alloy surfaces. The obtained results are compared to the characteristics of Zr-based conversion coatings that were subsequently generated on top of these substrates. Focus is laid on typical elemental distributions on the sample surfaces, in particular on the amount of precipitated functional additives such as Cu species that are present in the substrate matrix as well as in the conversion bath solutions. To this aim, Field Emission Auger Electron spectra, depth profiles and surface maps with superior local resolution were acquired and compared to scanning electron microscopy images of the sample. The results show how de-alloying processes, which occur at and around intermetallic particles in the Al matrix during typical industrial alkaline or acidic cleaning procedures, provide a significant source of crystallization cores for any following coating processes. This is in particular due for Cu-species, as the resulting local Cu structures on the surface strongly affect the film formation and compositions of state-of-the-art Zr-based films. The findings are highly relevant for industrial treatments of aluminium surfaces, especially for those that undergo corrosion protection and painting process steps prior to usage.

  17. Analysis of Bi-directional Effects on the Response of a Seismic Base Isolation System

    International Nuclear Information System (INIS)

    Park, Hyung-Kui; Kim, Jung-Han; Kim, Min Kyu; Choi, In-Kil

    2014-01-01

    The floor response spectrum depends on the height of the floor of the structure. Also FRS depends on the characteristics of the seismic base isolation system such as the natural frequency, damping ratio. In the previous study, the floor response spectrum of the base isolated structure was calculated for each axis without considering bi-directional effect. However, the shear behavior of the seismic base isolation system of two horizontal directions are correlated each other by the bi-directional effects. If the shear behavior of the seismic isolation system changes, it can influence the floor response spectrum and displacement response of isolators. In this study, the analysis of a bi-directional effect on the floor response spectrum was performed. In this study, the response of the seismic base isolation system based on the bi-directional effects was analyzed. By analyzing the time history result, while there is no alteration in the maximum shear force of seismic base isolation system, it is confirmed that the shear force is generally more decreased in a one-directional that in a two-directional in most parts. Due to the overall decreased shear force, the floor response spectrum is more reduced in a two-directional than in a one-directional

  18. Block copolymer based composition and morphology control in nanostructured hybrid materials for energy conversion and storage: solar cells, batteries, and fuel cells

    KAUST Repository

    Orilall, M. Christopher

    2011-01-01

    The development of energy conversion and storage devices is at the forefront of research geared towards a sustainable future. However, there are numerous issues that prevent the widespread use of these technologies including cost, performance and durability. These limitations can be directly related to the materials used. In particular, the design and fabrication of nanostructured hybrid materials is expected to provide breakthroughs for the advancement of these technologies. This tutorial review will highlight block copolymers as an emerging and powerful yet affordable tool to structure-direct such nanomaterials with precise control over structural dimensions, composition and spatial arrangement of materials in composites. After providing an introduction to materials design and current limitations, the review will highlight some of the most recent examples of block copolymer structure-directed nanomaterials for photovoltaics, batteries and fuel cells. In each case insights are provided into the various underlying fundamental chemical, thermodynamic and kinetic formation principles enabling general and relatively inexpensive wet-polymer chemistry methodologies for the efficient creation of multiscale functional materials. Examples include nanostructured ceramics, ceramic-carbon composites, ceramic-carbon-metal composites and metals with morphologies ranging from hexagonally arranged cylinders to three-dimensional bi-continuous cubic networks. The review ends with an outlook towards the synthesis of multicomponent and hierarchical multifunctional hybrid materials with different nano-architectures from self-assembly of higher order blocked macromolecules which may ultimately pave the way for the further development of energy conversion and storage devices. © 2011 The Royal Society of Chemistry.

  19. Innovative direct energy conversion systems from fusion output thermal power to the electrical one with the use of electronic adiabatic processes of electron fluid in solid conductors

    International Nuclear Information System (INIS)

    Kondoh, Y.; Kondo, M.; Shimoda, K.; Takahashi, T.; Osuga, K.

    2003-07-01

    It is shown that with the use of the fusion output and/or environmental thermal energy, innovative open systems for permanent auto-working (PA) direct energy converting (DEC) from the thermal to the electrical (TE) and further to the chemical potential (TEC) energies, abbreviated as PA-TEC-DEC systems, can be used for new auto-working electrical power plants and the plants of the compressible and conveyable hydrogen gas resources at various regions in the whole world. It is analytically shown that the same physical mechanism by free electrons and electrical potential determined by temperature in conductors, which include semiconductors, leads to the Peltier effect and the Seebeck one. It is analytically proved that the energy conservation law is exactly satisfied in a simple form where the net absorbed thermal power is directly transferred to the electrical power and to the chemical power in the PA-TEC-DEC systems. It is analytically and experimentally clarified that the long distance separation between two π type elements of the heat absorption side and the production one of the Peltier effect circuit system or between the higher temperature side and the lower one of the Seebeck effect circuit one does not change mechanisms of the heat pumping by the Peltier effect and of the TE-DEC by the Seebeck effect. The proposed systems gives us freedom of no using the fossil fuel, such as coals, oils, and natural gases that yield serious greenhouse effect all over the earth, and the plant of nuclear fissions that left radiating wastes, i.e., no more environmental pollutions. The PA-TEC-DEC systems can be applicable for several km scale systems to the micro ones, such as the plants of the electrical power and the hydrogen gas resources, compact transportable hydrogen gas producers, the refrigerators, the air conditions, home electrical apparatuses, and further the computer elements. (author)

  20. Kraft lignin depolymerisation by based catalysed degradation (BCD) - The effect of process parameters on conversion degree and structural features of BCD fractions

    OpenAIRE

    Schmiedl, Schmiedl; Böringer, Sarah; Schweppe, Rainer; Liitiä, Tiina; Rovio, Stella; Tamminen, Tarja; Rencoret, Jorge; Gutiérrez Suárez, Ana; Río Andrade, José Carlos del; Río Andrade, José Carlos del

    2014-01-01

    The objective of the study is the generation of oxy-aromatic compounds (monomer, oligomer) from Eucalyptus- Kraft-lignin via multi-stage processes. These processes (1st base catalysed degradation & 2nd separation of the organic phase from reactor water) have to be feasible in bio refineries & in new Pulp-mill bio refineries as a new technology module. The Eucalyptus-Kraft-lignin (Suzano Pulp & Paper) was used for catalyzed conversion into oxy aromatics. Subsequently, the effect of process par...